ILIAS Seminars

Contact and getting there

ILIAS is the Interdisciplinary Lab for Intelligent and Adaptive Systems at the University of Luxembourg. The ILIAS seminars are held at Campus Kirchberg. The seminars are coordinated by Giovanni Casini, who is also maintaining this web-site. In case of questions, remarks, or suggestions about the seminar or the web-site, feel free to

Incoming talks

October 14, 2016

Seminar room E112, 3pm-4pm

Speaker: Kristijonas Čyras (Imperial College London)

Title: Structured argumentation with preferences: the ABA+ formalism

Abstract: I am going to talk about structured argumentation with preferences. More specifically, I will focus on ABA+, a new formalism that extends with preferences the well established structured argumentation formalism Assumption-Based Argumentation (ABA). ABA+ deals with preferences on the object level (particularly, over assumptions) and incorporates them directly into the attack relation so as to reverse some attacks, as opposed to the majority of argumentation formalisms which use preferences to discard attacks. I will talk about some desirable properties that ABA+ exhibits and its place among other formalisms. In addition, I would like to, and will try to talk about a well known principle of contraposition (on rules) in structured argumentation. More specifically, I will propose Weak Contraposition, a principle that relaxes standard contraposition at the same time concerning contrapositive reasoning in the presence of preferences. I will talk about the role of Weak Contraposition in ABA+, its relation to some other principles of contrapositive reasoning in structured argumentation, and will try to illustrate with interesting examples. I should also like to present the system ABAplus that implements reasoning with ABA+ subject to Weak Contraposition, and will be grateful for any feedback.

Past talks

July 12, 2016

Seminar room E112, 3pm-4pm

Speaker: Jesse Heyninck (Ruhr-Universität Bochum)

Title: Reasoning by Cases in Structured Argumentation*

Abstract: We extend the ASPIC+ framework for structured argumentation so as to allow applications of the reasoning by cases inference scheme for defeasible arguments. Given an argument with conclusion ‘A or B’, an argument based on A with conclusion C, and an argument based on B with conclusion C, we allow the construction of an argument with conclusion C. We show how our framework leads to different results than other approaches in non-monotonic logic for dealing with disjunctive information, such as disjunctive default theory or approaches based in the OR-rule (which allows to derive a defeasible rule ‘If (A or B) then C’, given two defeasible rules ‘If A then C’ and ‘If B then C’). This way, we raise new questions regarding the subtleties of reasoning defeasibly with disjunctive information. This talk is based on joint work with Mathieu Beirlaen and Christian Straßer.

May 26, 2016

Seminar room E112, 4pm-5pm

Speaker: Dimitrios Kampas (Univesity of Luxembourg)

Tryout presentation for Phd thesis defense

Title: Topic Identification Considering Word Order in Markov Chains

Abstract: Automated topic identification of text has gained a significant attention since a vast amount of documents in digital forms are widespread and continuously increasing. Probabilistic topic models are a family of statistical methods that unveil the latent structure of the documents defining the model that generates the text a priori.

They infer about the topic(s) of a document considering the bag-of-words assumption, which is unrealistic considering the sophisticated structure of the language. The result of such a simplification is the extraction of topics that are vague in terms of their interpretability since they disregard any relations among the words that may settle word ambiguity. Topic models miss significant structural information inherent in the word order of a document.

In this thesis we introduce a novel stochastic topic identifier for text data that addresses the above shortcomings. The primary motivation of this work is initiated by the assertion that word order reveals text semantics in a human-like way. Our approach recognizes an on-topic document trained solely on the experience of an on-class corpus. It incorporates the word order in terms of word groups to deal with data sparsity of conventional n-gram language models that usually require a large volume of training data. Markov chains hereby provide a reliable potential to capture short and long range language dependencies for topic identification. Words are deterministically associated with classes to improve the probability estimates of the infrequent ones. We demonstrate our approach and motivate its eligibility on several datasets of different domains and languages. Moreover, we present a pioneering work by introducing a hypothesis testing experiment that strengthens the claim that word order is a significant factor for topic identification. Stochastic topic identifiers are a promising initiative for building more sophisticated topic identification systems in the future.

May 18, 2016

Seminar room E112, 4pm-5pm

Speaker: Souhila Kaci (Université de Montpellier)

Title: On Preferences and Argumentation

Abstract: Preferences are the backbone of various fields as they naturally arise and play an important role in many real-life decisions. Therefore preferences has become a core topic in AI for which we are witnessing plenty of work covering modeling, representing and reasoning with preferences. In this talk I will give an overview of some preference representation languages with a particular emphasis on conditional logics. Then I will present value-based argumentation with conditional logis. Time permitting, I will also present valued preferences-based argumentation.

May 9, 2016

Seminar room E112, 4pm-5pm

Speaker: Gillman Payette (Dalhousie University, Canada)

Title: On Imposing Uniform Responsibility

Abstract: In this talk I explore the effects of imposing van Hees and Braham's notion of uniformity on game forms and an analogous condition on Belnap et al.'s stit models. In the first case, Braham and van Hees have shown that a dictatorship result follows when uniformity is imposed on game forms which also include a probabilistic component for modelling responsibility. In the case of stit theory, I show that the probabilistic component is unnecessary for deriving a dictatorship result. I compare the results, and comment on the use of stit theory for modelling intentions.

March 22, 2016

Seminar room E112, 4pm-5pm

Speaker: Thomas Studer (Univesity of Bern)

Title: Justification logic

Abstract: Traditional modal logics feature formulas of the form K A that stand for 'the agent knows that A'. The classical semantics for these logics is given by possible world models, in which the formula K A is true if A is true in all worlds that the agent considers possible. However, this approach is missing the justified part of Plato's classic characterization of knowledge as justified true belief. Justification logics can fill this gap. Instead of formulas K A, the language of justification logics includes formulas of the form t : A that mean 'the agent knows that A for reason t'. The evidence term t in this expression can represent a formal proof of A or an informal reason why A is known. Moreover, justification logics include operations on these terms to reflect the agent's reasoning power. For instance, if A -> B is known for reason s and A is known for reason t, then B is known for reason s x t, where the binary operation x models the agent's ability to apply modus ponens. In our talk, we give an introduction to justification logic and present some of the main results in this area.

February 17, 2016

Seminar room E112, 4pm-5pm

Speaker: Tommaso Flaminio (Univesità dell'Insubria)

Title: A logical approach to subjective probability theory and its generalizations

Abstract: In this talk we will present a modal fuzzy approach to subjective probability theory. In specific terms, starting from some historical remarks, we will focus on a modal logic introduced by Hàjek, Godo and Estava built upon propositional Lukasiewicz logic and aimed at capturing the rules of probabilistic reasoning. After a brief and rather superficial presentation of some of its generalizations that capture conditional probability, probability of many-valued events and alternative uncertainty measures, we will finally present a purely universal-algebraic approach to probability measures on infinite-valued events.

February 15, 2016

Seminar room E112, 4pm-5pm

Speaker: Sophia Ananiadou (University of Manchester)

Title: Text mining tools and infrastructure for biomedical applications

Abstract: Text mining plays a key role in automatic semantic metadata extraction, driving the extraction of structured information from unstructured documents, which results in annotations in the form of named entities or fine-grained relations between them. However, many text mining resources differ from each other in terms of various dimensions, e.g., subject domain, input/output format, language and semantic representation. The ability to develop complex solutions by combining different text mining resources is thus hindered by issues of incompatibility. I will explain how such issues can be alleviated by NaCTeM's text mining infrastructure, Argo which fosters interoperability of resources by giving its users access to an environment that supports the integration of diverse corpora, terminologies and tools into unified solutions.

I will focus on two application areas: a) the creation of text mining workflows for the automatic extraction of cancer-related events and their interpretation from the scientific literature to support pathway construction as part of the DARPA Big Mechanism programme. Using our reconfigurable text mining infrastructure , interactions were extracted from the literature and mapped to the reactions contained in cancer pathway models to identify new, corroborating or conflicting information with respect to the pathways
b) the development of a search system from historical text archives to support historians of medicine using our modular pipeline approach.

February 3, 2016

Seminar room E112, 4pm-5pm

Speaker: Cesare Bartolini (University of Luxembourg)

Title: Ontology mutation testing

Abstract: Mutation testing is a well-known testing technique which combines error injection and unit testing. Mutation testing is an approach that tests the efficiency of the test suite, but in doing so it also allows to achieve a better understanding of the System Under Test (SUT). This work extends mutation testing techniques to ontologies expressed in the OWL language. Mutation operators on OWL ontologies change the semantics of the ontology, regardless of the syntax in which it is expressed. Mutation testing can assist the designer in the identification of potential flaws and in the maintainance of the ontology.

December 9, 2015

Seminar room E112, 4pm-5pm

Speaker: Christian Straßer (University of Bochum)

Title: Detaching Obligations: An Argumentative Approach

Abstract: We present a general framework for dealing with the detachment of conditional obligations. Given some facts and conditional obligations, the question whether an unconditional obligation holds is determined by considering reasons for and against its detachment. For this, we use a Dung-style argumentation-theoretical semantics. This part of the talk is joint work with Mathieu Beirlaen (RUB). In the second part of the talk I will present a dynamic proof theory for the system. This part of the talk is based on joint work with Jesse Heyninck (RUB).

November 9, 2015

Seminar room E112, 4pm-5pm

Speaker: Joris Hulstijn (Delft University)

Title: Reliability of Electronic Evidence: supervision of a customs warehouse

Abstract: Much legal evidence is being generated by and stored in information systems. In this talk I will discuss quality of evidence from an auditing point of view. I will present an approach called model-based auditing. It is based on a mathematically precise model of the expected relationships between the flow of money and the flow of goods or services. Such equations are used for cross verification of independent sources. To show the usefulness of the approach, I will discuss a case study of the customs warehouse at ASML. Supervision is done by means of electronic periodic declarations (EPD): monthly reports of the customs relevant movements in the warehouse management system. I will discuss in particular how to establish completeness and correctness of these reports.The formal modeling of the notion of knowing-how is important from both an AI perspective and a philosophical perspective. In AI de notion is / should be central in agent programming and practical reasoning. In philosophy, a formal account of the notion can shed some much needed light on the various claims and approaches to understanding and conceptualizing knowing-how. I will present our formalization in strategic stit logic.

October 7, 2015

Seminar room E112, 4pm-5pm

Speaker: Jan Broersen (University of Utrecht)

Title: The Formal Modeling of Knowing-How

Abstract: The formal modeling of the notion of knowing-how is important from both an AI perspective and a philosophical perspective. In AI de notion is / should be central in agent programming and practical reasoning. In philosophy, a formal account of the notion can shed some much needed light on the various claims and approaches to understanding and conceptualizing knowing-how. I will present our formalization in strategic stit logic.

October 6, 2015

Seminar room E112, 4pm-5pm

Speaker: Paolo Turrini (Imperial College London)

Title: Rethinking backwards induction in long extensive games

Abstract: For classical game theory chess is an uninteresting game. It is a finite extensive game of perfect information that can (therefore) be solved by backwards induction, and that's the end of it.

For artificial intelligence - as well as for human beings - chess is a very interesting game. This because, in practice, humans (and even supercomputers) are not able to correctly assess game positions and decide the best thing to do. In other words, they make mistakes.

What I present in this talk is a model of interactive decision-making in chess-like scenarios, where participants are not able to foresee the consequences of their decisions all the way up to the terminal nodes and need to make a judgement call to evaluate intermediate game positions.

On top of that players can form beliefs about what the other players are able to foresee and how they evaluate it, and all higher order variants thereof (beliefs about beliefs of others, beliefs about beliefs about beliefs of others and so forth).

I will introduce and analyse a solution concept to solve these scenarios, which is a generalisation of classical backwards induction, and where players' local decisions are a best response to the (higher-order) beliefs they hold about the other players' foresight and evaluation criteria. In other words, they play rationally against their opponents' believed weaknesses.

I will also show that the potentially unbounded chain of complex beliefs sustaining this solution concept can be computed using a PTIME algorithm.

*This talk builds upon a line of research started with Davide Grossi and being developed further with Davide and Johan van Benthem

**There is no deep game-theoretic background required to understand what I will be saying. It does help though if you played chess, at least once in your life.

September 28, 2015

Seminar room E112, 4pm-5pm

Speaker: Sylwia Polberg (TU Wien)

Title: Intertranslatability of Abstract Argumentation Frameworks

Abstract: At the heart of abstract argumentation lies the Dung argumentation framework. Over the years, many of its extensions were proposed, ranging from the ones employing various strengths and preferences to those that focus on researching new types of relations between arguments. With this amount of available structures, it is natural to ask whether one can move between the frameworks while still preserving the behavior of the semantics, what would be the costs of such a process and what we gain or lose in it. The aim of this work is to introduce new translations between the available frameworks and recall existing ones when possible, thus creating a comprehensive study on the intertranslatability of abstract argumentation frameworks. We also propose a translation classification system and new transformation approaches for structures with support. Finally, we discuss the quality of our translations and show what can or cannot be improved.

May 22, 2015

Seminar room E112, 2pm-3pm

Speaker: Ali Paikan (Istituto Italiano di Tecnologia)

Title: A middle way for robotics middleware

Abstract: Robotics software community is continuing to grow. The amount of software available (and needed) is growing. For better or worse, the glue that holds that software together, the middleware, has a big impact on its viability. Systematically developing high-quality reusable software components is a difficult task and requires careful design to find a proper balance between potential reuse, functionalities and ease of implementation. YARP is a middleware for robotics, with over a decade's continuous use on various humanoid robots. It was designed to help code survive changes, to easily experiment with new code and integrate with other systems. In a world of constant transition, with a steady stream of hardware and software upgrades, YARP helps code last long enough to make a real impact, and avoid premature loss of good code through middleware muddles. In this talk, I review the main features of YARP that support this flexibility, describing those situations in which they have been practically useful. Moreover, I provide an insight into the ongoing research projects within the department of the iCub Facility.

Bio: Ali Paikan is currently a Postdoctoral researcher at the Istituto Italiano di Tecnologia (IIT) in the iCub Facility department. He accomplished his Ph.D. in Robotics at the IIT in 2014 and he received the double M.S. degree from the University of Genova, in 2010, Italy and from the Ecole Centrale de Nantes, France in 2009, within the joint European Master on Advanced Robotics (EMARO). During his research period (2005 - 2007) at the Mechatronics Research Laboratory (MRL), Iran, Ali was actively involved and awarded in various RoboCup competitions. He has an extensive background in robotics and his main research interests include software architectures for robotics, software reusability and real-time systems. Recently, Ali has been involved in different European FP7 projects such as WALK-MAN, XPERIENCE and POETICON++ and has a close collaboration with Karlsruhe Institute of Technology (KIT).Social commitment is a key abstraction for modeling interaction among autonomous parties. In this talk, I will discuss two complementary techniques for computing commitments in settings where agents communicate asynchronously and each agent has its own information store in which it records its communications. One technique concerns how to model expressive information-based commitment specifications and how to track the states of an agent's commitments from the contents of its information store. The other technique concerns the alignment, in other words, the interoperability, of agents with respect to the commitments in their information stores. Informally, agents would be aligned if they agree sufficiently on their commitments. The two techniques yield the design of a middleware for interaction. I will also discuss some interesting directions of research.

April 24, 2015

Seminar room E112, 2:30pm-3:30pm

Speaker: Monica Palmirani

Title: LegalRuleML Standard for modelling Legal Norms

Abstract: The lecture presents the principles of the OASIS LegalRuleML applied to the legal domain and discuss why, how, and when LegalRuleML is well-suited for modelling norms. To provide a framework of reference, we present a comprehensive list of requirements for devising rule interchange languages that capture the peculiarities of legal rule modelling in support of legal reasoning. The lecture comprises syntactic, semantic, and pragmatic foundations (LegalRuleML primer sources online), a comparison with related other approaches, as well as use case examples from the legal domain. Social commitment is a key abstraction for modeling interaction among autonomous parties. In this talk, I will discuss two complementary techniques for computing commitments in settings where agents communicate asynchronously and each agent has its own information store in which it records its communications. One technique concerns how to model expressive information-based commitment specifications and how to track the states of an agent's commitments from the contents of its information store. The other technique concerns the alignment, in other words, the interoperability, of agents with respect to the commitments in their information stores. Informally, agents would be aligned if they agree sufficiently on their commitments. The two techniques yield the design of a middleware for interaction. I will also discuss some interesting directions of research.

March 20, 2015

Seminar room E112, 4pm-5pm

Speaker: Amit Chopra (Lancaster University)

Title: Commitment Computation in Distributed Settings: Information and Alignment

Abstract: Social commitment is a key abstraction for modeling interaction among autonomous parties. In this talk, I will discuss two complementary techniques for computing commitments in settings where agents communicate asynchronously and each agent has its own information store in which it records its communications. One technique concerns how to model expressive information-based commitment specifications and how to track the states of an agent's commitments from the contents of its information store. The other technique concerns the alignment, in other words, the interoperability, of agents with respect to the commitments in their information stores. Informally, agents would be aligned if they agree sufficiently on their commitments. The two techniques yield the design of a middleware for interaction. I will also discuss some interesting directions of research.

Bio: Amit Chopra is a lecturer in the School of Computing and Communications at Lancaster University in the UK. His interests lie broadly at the intersection of multiagent systems, software engineering, and social computing. Amit has a PhD in computer science from North Carolina State University (2008).Gelfond’s epistemic specifications extend the language of ASP by modal operators in order to correctly represent incomplete information in situations when there are multiple answer sets, alias belief sets. We here extend a more general language of here-and-there logic by modal operators of knowledge and belief. We show that the resulting epistemic extension of equilibrium logic embeds epistemic specifications. We also show that we can capture strong equivalence of two epistemic specifications.

November 26, 2014

Seminar room E112, 4pm-5pm

Speaker: Ezgi Iraz Su (Université Paul Sabatier de Toulouse)

Title: From Epistemic Specifications to Epistemic ASP

Abstract: Gelfond’s epistemic specifications extend the language of ASP by modal operators in order to correctly represent incomplete information in situations when there are multiple answer sets, alias belief sets. We here extend a more general language of here-and-there logic by modal operators of knowledge and belief. We show that the resulting epistemic extension of equilibrium logic embeds epistemic specifications. We also show that we can capture strong equivalence of two epistemic specifications.

November 19, 2014

Seminar room E112, 4pm-5pm

Speaker: Yehia Elrakaiby (Fraunhofer Institute for Experimental Software Engineering)

Title: Security@Runtime: A Framework for the Specification and Enforcement of Usage Control Policies

Abstract: Most organizations today are subject to different regulations. These could be legal requirements such as controls regarding the processing of users’ private information, restrictions for maintaining the integrity of financial systems or simply internal guidelines for the protection of organizations’ sensitive assets. Compliance with these regulations is often mandatory and violations may result in financial or reputation losses for organizations. In this talk, we present the Security@Runtime (S@R) framework for the specification and enforcement of usage control policies. S@R provides an elegant language for the encoding of regulatory requirements in the form of usage policies, and an enforcement architecture to enable a target system to comply with these policies. The presentation will cover the S@R architecture, language, integration aspects and semantics. A use case for the application of the application to secure Java-based systems is presented and, if time allows it, the automated analysis of usage control policy specifications will be discussed.

November 12, 2014

Seminar room E212, 4pm-5pm

Speaker: Sylvain Lagrue (Centre de Recherche en Informatique de Lens)

Title: Incomparability, incommensurability, and collisions in reasoning and belief change

Abstract: Situated in the area of ​​Artificial Intelligence, our works focus on two main research topics: reasoning and deciding from uncertain beliefs and the dynamics of these beliefs. The management of incomparability and incommensurability problems that may arise when sources of information are highly heterogeneous specifically interests us.

We first present some formalisms used when an agent has to reason in the presence of inconsistencies and uncertainty, in a purely ordinal point of view and then in a more numerical way. In the first case, we propose and study different generalizations of well-known methods of reasoning. These generalizations allow us to manage incomparability. In a more numerical context, we extended possibilistic logic for representing the uncertainty associated with the information by means of interval values. We also proposed different methods to improve the productivity of inferences based on the penalty logic in order to avoid collisions.

In the context of dynamics of beliefs, we propose a new set of postulates for revising epistemic states represented by partial preorders. We present different operators, their logical properties and a representation theorem. We are also interested in the generalization of the merging process in the case where agents do not share a single scale, for instance when the weights they provide are incommensurable. We propose different operators for modeling this process, a logical study, as well as an impossibility theorem.

November 10, 2014

Seminar room E212, 4pm-5pm

Speaker: Aditya Ghose (University of Wollongong)

Title: Semantic monitoring and compensation in socio-technical processes: Lessons for the computation of reparations

Abstract: Socio-technical processes are becoming increasingly important, with the growing recognition of the computational limits of full automation, the growth in popularity of crowd sourcing, the complexity and openness of modern organizations etc. A key challenge in managing socio-technical processes is dealing with the flexible, and sometimes dynamic, nature of the execution of human-mediated tasks. It is well-recognized that human execution does not always conform to predetermined coordination models, and is often error-prone. This talk addresses the problem of semantically monitoring the execution of socio-technical processes to check for non-conformance, and the problem of recovering from (or compensating for) non-conformance. I will discuss a semantic solution to the problem, by leveraging semantically annotated process models to detect non-conformance, and using the same semantic annotations to identify compensatory human-mediated tasks. I will also highlight how this holds lessons for the computation of reparations in norm-driven systems.

October 13, 2014

Seminar room E112, 4pm-5pm

Speaker: Srdjan Vesic (Centre de Recherche en Informatique de Lens)

Title: A weakening of independence in judgment aggregation: agenda separability

Abstract: One of the better studied properties for operators in judgment aggregation is independence, which essentially dictates that the collective judgment on one issue should not depend on the individual judgements given on some other issue(s) in the same agenda. Independence is a desirable property for various reasons, but unfortunately it is too strong, as, together with mild additional conditions, it implies dictatorship. We propose a weakening of independence, named agenda separability: a judgment aggregation rule satisfies it if, whenever the agenda is composed of several sub-agendas that are syntactically unrelated to each other, the resulting collective judgment sets can be computed separately for each sub-agenda and then put together. We show that this property is discriminant, in the sense that among judgment aggregation rules so far studied in the literature, some satisfy it and some do not. We also propose several strengthenings of agenda separability that allow the sub-agendas to be partly syntactically related.

July 7, 2014

Seminar room E112, 3pm-4pm

Speaker: Marija Slavkovik (University of Bergen)

Title: A licence to assist - Ethical autonomous systems amenable to certification via formal verification

Abstract: Autonomous systems in existence are designed to either have no ability to cause harm to life and property, or to operate in a controlled environment segregated from people. For example, iRoomba has no power to hurt anyone or anything and autonomous cars, aircraft and trains do not share space with men driven vehicles. For autonomous systems to be cheaper and more useful we need to find a way to integrate them in our society and the necessary step for that is certification. It has been shown that, for hybrid autonomous systems, formal verification can be used to guarantee that the system conforms to societal rules of behaviour. However, an additional dimension to accepting autonomous systems in society, not explicitly specified in rules of behaviour, is ethical behaviour. In this talk I present our current work on incorporating and verifying ethical behaviour within hybrid autonomous systems. I shall also discuss the challenges and open questions that arise from designing ethical behaviour for intelligent agents.

June 30, 2014

Seminar room E112, 3pm-4pm

Speaker: Dragan Doder (University of Luxembourg)

Title: Logics with probability operators

Abstract: Mathematical representation of probabilistic reasoning extends basic logical language with probabilistic operators and probabilistic quantifiers. In this talk, I will present a modal-based approach to probabilistic logic, with unary probability operators. Probabilistic extensions of different underlying logics will be considered. The focus will be on one of the main proof-theoretical problems: providing a strongly complete axiomatic system. This problem originates from the inherent non-compactness of the so called non-restricted real-valued probabilistic logics.

June 26, 2014

Seminar room E112, 11am-12pm

Speaker: Massimiliano Giacomin (Universitá degli Studi di Brescia)

Title: A review of semantics properties in abstract argumentation

Abstract: Dung's framework provides an abstract view of argumentation where the origin and the structure of arguments are left unspecified, and the interaction between them is simply modeled as a binary relation indicating that an argument attacks another one. Despite this simplicity, a great number of semantics have been identified, along with several example-independent criteria for evaluating and comparing such semantics. More recently, some semantics properties -including directionality and SCC-recursiveness- have been exploited to support local and incremental computation of extensions, in order to reduce the computational effort and to manage argumentation dynamics. Furthermore, a recent investigation on the input/output behavior of argumentation frameworks has identified additional semantics properties, including decomposability and transparency. While different properties have been devised with different motivations, some similarities and, sometimes, subtle differences between them can be identified. The talk will review a number of semantics properties focusing on their relationships and on possible directions for future investigation.

June 24, 2014

Seminar room E112, 3pm-4pm

Speaker: Pietro Baroni (Universitá degli Studi di Brescia)

Title: On the uses of numbers in abstract argumentation

Abstract: Interest in the use of numbers in argumentation in general and, in particular, in the context of the formalism of abstract argumentation frameworks is gaining momentum in last years, with a variety of proposals appearing in recent literature where numbers are used in various different ways and sometimes with very different meanings, in spite of possible formal similarities. The lack of a reference framework, explicitly stated assumptions, and shared principles, makes difficult to assess and compare these proposals in a systematic way and also to point out some possibly overlooked potential lines of development for numerical argumentation. The talk will present an ongoing work aimed at laying out a systematic classification of the uses and meanings of numbers in abstract argumentation, with focus on placing some prominent literature proposals in the picture and on discussing directions for future investigation.

June 5, 2014

Seminar room E112, 11am-12pm

Speaker: Matteo Baldoni (Universitá di Torino)

Title: Social Computing with 2COMM

Abstract: Social Computing (SC) requires agents to reason seamlessly both on their social relationships and on their goals, beliefs. We claim the need to explicitly represent the social state and social relationships as resources, available to agents. We built a framework, 2COMM, based on Cartago, where this vision is realized and Social Computing is implemented through social commitments and commitment protocols. Two integrations, one with JADE and one with Jason are also presented

March 31, 2014

Seminar room E112, 4pm-5pm

Speaker: Catalin Dima (Université Paris-Est Créteil)

Title: Safraless synthesis from epistemic temporal specifications

Abstract: We present a novel algorithm for synthesizing strategies satisfying specifications given in a fragment of the Linear Temporal Logic with Knowledge (LTLK) in one-agent-against-environment systems with partial information and perfect recall. Our technique is inspired from recent work on synthesis from LTL specifications using antichain-based algorithms. This allows us to avoid the difficulties that are posed by the implementation of the original algorithms proposed by van der Meyden and Vardi in their Concur'98 paper, algorithms which rely on Safra's construction for complementing Büchi automata, a construction which is well-known to be resistant to efficient implementationns. Our approach has been tested with encouraging results on some case studies, in which our implementation is able to handle tree automata with several thousand states.
We also report on ongoing work towards extending these results to the full LTLK using a new class of automata equivalent with LTLK formulas.

March 20, 2014

Seminar room E112, 4pm-5pm

Speaker: Ringo Baumann (University of Leipzig)

Title: Context-free and Context-sensitive Kernels – Characterizing Update and Deletion Equivalence

Abstract: Notions of equivalence which guarantee intersubstitutability w.r.t. further modifications have received considerable interest in nonmonotonic reasoning. This paper is within the context of abstract argumentation and we focus on the most general form of a dynamic scenarios, so-called updates as well as certain subclasses, namely local, normal and arbitrary deletions. We provide characterization theorems for the corresponding equivalence notions and draw the relations to the recently proposed kinds of expansion equivalence. Many of the results rely on abstract concepts like context-free kernels or semantics satisfying isolate-inclusion. Therefore, the results may apply to future semantics as well as further equivalence notions

March 13, 2014

Salle du Conseil, 10:30-11:30

Speaker: Dov Gabbay (King's College London, University of Luxembourg)

Title: Delegation, Count as, and Security in Talmudic Logic

Abstract: Delegation is a commonplace feature in our society. Individuals give power of attorney to their lawyers to perform certain actions for them (e.g. buy or sell property), institutions delegate to certain employees to sign for them (human resources send letters of appointment) and owners can grant access and administrative rights to other people in relation to their servers.

The logic behind such a system has been studied by several communities. In philosophy this is known as “count as”. X counts as Y in context C. In law there are various rules for power of attorney. In computer science one talks about access control and delegation. This paper examines the approach to delegation in Talmudic Logic.

The current approaches to delegation, mainly study three features
1. Dominance — if several primary sources delegate to secondary sources who carry on delegating then what is the dominance relationship among the chains of delegations
2. Revocation — if some sources revoke the delegation or some change their minds and reinstate, how does this propagate through the chains of delegations?
3. Resilience — if one source revokes delegation do we cancel other delegations from other sources on the grounds that we now do not trust the delegate?

In the literature systems have been constructed which either model or implement a calculus of Delegation-Revocation ( Privilege calculus). Their purpose is to answer the question of whether the chain of delegation and revocations can allow an agent to perform an action and their models are chain update models.

The Talmudic approach is slightly different not only in the details of its model but also in its point view.

The Talmud not only examines the procedure of the actual acts of delegation and revocation and its calculus but also includes the analysis of ordinary actions (not just chain update actions) — their elements of agency, action, deliberation and competence. These attributes have preconditions addressing not only acts but also delegation and revocation chains leading to the actions. The Talmud also addresses cases of delegated agents unable to execute the actions for various reasons, and the possibility of agents going mad or dying during the delegation revocation process, with their repercussions.

February 24, 2014

Seminar room E112, 4pm-5pm

Speaker: Adam Wyner (University of Aberdeen)

Title: Topics on the Linguistics and Logic of Deontic Concepts

Abstract: Linguists and logicians have not, generally, collaborated on research about the deontic concepts of obligations, prohibitions, and permissions. Each 'camp' had a distinct approach: linguists considered linguistic data, syntax, the syntax-semantics interface, and compositional representation; logicians considered modal logical systems. It appeared that there were few common problems, and there was little impact of one on the other. However, it seems that this has begun to change - see the USC Deontic Modality Workshop 2013 and DEON 2014. By way of contributing to and stimulating this development, the talk touches briefly on several topics from the speaker's past research on the language and logic of deontic concepts bearing on: lexical semantics, conditionals and obligations (does Axiom K appear in natural language?), adverbs and obligations, the Good Samaritan Paradox, compositionality of violation conditions and violation markers, and the practical issues associated with knowledge extraction and formalisation from text.

February 21, 2014

Seminar room E112, 10am-11am

Speaker: Clara Smith (University of Bologna)

Title: Reflex Responsibility of Agents

Abstract: There are occasions in which an agent lengthens its own action through the implementation of a foreign activity for its own interests. We focus on the occasional relation between a principal agent and a helper agent. In particular, we are interested in the helper’s harmful performance that has its origin in extra contractual situations e.g. factual and/or occasional situations based on trust or courtesy which may lead to the emergence of an obligation to compensate third parties.

February 10, 2014

Seminar room E112, 10am-11am

Speaker: Ivan José Varzinczak (UKZN/CSIR Meraka Centre for Artificial Intelligence Research, South Africa)

Title: Modal Logics of Defeasibility

Abstract: Historically, approaches to defeasible reasoning have been concerned mostly with one aspect of defeasibility, viz. that of arguments, which is usually characterized by the presence of some notion of ‘conditional’ that fails monotonicity. Research on non-monotonic logics is therefore largely concerned with the defeasibility of argument forms and the associated normality (or abnormality) of its constituents. In this talk we are interested in another aspect of defeasibility, namely that of defeasible modes of inference. These aim to formalize the defeasible aspects of traditional modal notions such as actions, beliefs and knowledge, to name a few. To this end we define a modal logic which provides a general framework within which notions such as normal effects, normal knowledge and many others can be formalized. We do so by enriching the standard possible worlds semantics with a preference ordering on worlds in Kripke models, which allows us to refer to the relative normality of accessible worlds. The preference order informs the meaning of existing modal operators by considering minimality in accessible worlds, where accessibility is determined independently from the preference order. Defining preferential extensions of modal logics turns out to be particularly promising mostly because they are based on one of the most comprehensive and successful frameworks for nonmonotonic reasoning in the propositional case, namely the KLM approach. The resulting preferential modal logics make it possible to elegantly capture, and reason with, aspects of defeasibility heretofore beyond the reach of traditional modal formalisms. We also propose a tableau calculus which is sound and complete with respect to our preferential semantics, and of which the computational complexity remains in the same class as that of the underlying classical modal logic.

February 3, 2014

Seminar room E112, 2pm-3pm

Speaker: Patrick Allo (Vrije Universiteit Brussel)

Title: Is logic special?

Abstract: The traditional idea that logic is specially relevant for reasoning stems from the fact that logic is often conceived as an absolute normative constraint on what we should and should not believe (a synchronous constraint) and as an infallible guide for what we should (or may) come to believe in view of what we already believe (a diachronic constraint). This view is threathened by the existence of rational failures of deductive cogency; belief-states that do not conform to what logic would require, but that are never- theless more rational than any revised belief-state that would be deductively cogent.

The suggestion that belief-states that are not deductively cogent can still be rational depends itself on the view that logical norms like consistency or deductive closure can sometimes be overruled by extra-logical norms. The latter clearly poses a problem for views that grant logic a special role in reasoning. (The underlying idea is that the special role of logic is inconsistent with the presumed defeasible character of logical norms.)

There are many ways of coping with these insights.

  1. 1. One can just accept the conclusion that the received view about logic is wrong,
  2. 2. one can deny the existence of rational failures of deductive cogency, or
  3. 3. one can revise what we mean by logic and/or how we understand it's role in reasoning.

I'm only interested in the last type of response.

In particular, I'd like to focus on strategies that (a) rely on the use of non-classical logics, (b) claim that logic can be used to formalise defeasible reasoning forms, and (c) propose a logical model of belief and belief-revision. While each of these three strategies reduces the gap between logic and reasoning, and even share some of their formal resources, a unified philosophical account of such proposals is still missing.

My aim in this talk is relatively modest. I only want to develop a minimal model that integrates the crucial features of sub-classical logics, with models of belief that rely on defeasible reasoning and allow for belief-revision. The upshot is to distill an account of the special role of logic in reasoning that is consistent with our best formal (logical) models of belief.

The proposed account combines a modal reconstruction of adaptive consequence relations (Allo, 2013b) with a suggestion to adopt the finer distinctions of different types of group-knowledge (and belief) to model single-agent knowledge (and belief) (Allo, 2013a) and a formal model of belief-merge through communication (Baltag & Smets, 2013).

January 30, 2014

Seminar room E112, 4pm-5pm

Speaker: Serena Villata and Elena Cabrio (INRIA Sophia Antipolis)

Title: Argumentation meets Natural Language Processing: results achieved and open challenges

Abstract: In this talk we will present existing approaches coupling Argumentation Theory and Natural Language Processing, and then we will present our contributions in that area, highlighting the remaining open challenges. In order to cut in on a debate on the web, the participants need first to evaluate the opinions of the other users to detect whether they are in favor or against the debated issue. Bipolar argumentation proposes algorithms and semantics to evaluate the set of accepted arguments, given the support and the attack relations among them. Two main problems arise. First, an automated framework to detect the relations among the arguments represented by the natural language formulation of the users’ opinions is needed. Our talk addresses this open issue by proposing and evaluating the use of natural language techniques to identify the arguments and their relations. In particular, we adopt the textual entailment approach, a generic framework for applied semantics, where linguistic objects are mapped by means of semantic inferences at a textual level. Textual entailment is then coupled together with an abstract bipolar argumentation system which allows to identify the arguments that are accepted in the considered online debate. Second, we address the problem of studying and comparing the different proposals put forward for modeling the support relation. The emerging scenario shows that there is not a unique interpretation of the support relation. In particular, different combinations of additional attacks among the arguments involved in a support relation are proposed. We provide a natural language account of the notion of support based on online debates, by discussing and evaluating the support relation among arguments with respect to the more specific notion of textual entailment in the natural language processing field.

January 27, 2014

Seminar room E112, 4pm-5pm

Speaker: Frederik Van De Putte (University of Ghent)

Title: From norms to norm-propositions: modal input/output logics (based in part on joint work with Christian Strasser and Mathieu Beirlaen)

Abstract: We translate input/output-logics (originally developed by Makinson and van der Torre) to reflexive (non-monotonic) modal logics. The resulting reformulation has various advantages. First, we obtain a proof-theoretic (dynamic) characterization of input/output logics. Second, we demonstrate that our modal framework gives naturally rise to useful variants. Third, the modal logics display a gain in expressive power over their original counterparts in the input/output framework. Finally, the adaptive extensions allow us to manage defeasible input and constraints in various ways, within the same overall framework.

December 16, 2013

Seminar room E112, 4pm-5pm

Speaker: Livio Robaldo (University of Turin)

Title: Distributivity, Collectivity, and Cumulativity in terms of (In)dependence and Maximality

Abstract: Among the readings available for NL sentences, those where two or more sets of entities are independent of one another - termed in the talk as Independent Set readings - are particularly challenging. In the literature, examples of those readings are known as Collective and Cumulative readings. A new logical framework for NL quantification, based on Generalized Quantifiers, Skolem-like functional dependencies, and Maximality of the involved sets of entities is proposed. The framework seems to adequately deal with both Independent Set readings and standard linear readings in a scalable, natural, and uniform fashion.

November 14, 2012

Speaker: Guillaume Aucher (IRISA/INRIA)

Title: DEL-sequents for progression, regression and epistemic planning

Abstract: Dynamic Epistemic Logic (DEL) deals with the representation and the study in a multi-agent setting of knowledge and belief change. It can express in a uniform way epistemic statements about: (i) what is true about an initial situation (ii) what is true about an event occurring in this situation (iii) what is true about the resulting situation after the event has occurred. We axiomatize within the DEL framework what we can infer about (iii) given (i) and (ii), what we can infer about (ii) given (i) and (iii), and what we can infer about (i) given (ii) and (iii). These three inference problems are related to classical problems addressed under different guises in artificial intelligence and theoretical computer science, which we call respectively progression, epistemic planning and regression. Given three formulas F(i), F(ii) and F(iii) describing respectively (i), (ii) and (iii), we also show how to build three formulas which capture respectively all the information which can be inferred about (iii) from F(i) and F(ii), all the information which can be inferred about (ii) from F(i) and F(iii), and all the information which can be inferred about (i) from F(ii) and F(iii). We show how our results extend to other modal logics than K.

November 12, 2012

Speaker: Samir Chopra (Brooklyn College of the City University of New York)

Title: Outlines of a legal theory for autonomous artificial agents

Abstract: There is a wide spectrum of abilities and architectures available in the world of artificial agents; it is not an exaggeration to say the world of online commerce and network based governmental services would be crippled if human, corporate or governmental principals did not employ software based artificial agents to conduct business for them. As the number of interactions mediated by artificial agents increases, it will become increasingly important to carve out legal space for the artificial agent in order to do justice to its increasingly autonomous role within our networks of social, political and economic relations. Societal norms and the legal system constrain our interactions with other human beings (our fellow citizens or peoples of other nations), other legal persons (corporations and public bodies) or animal entities. There is, in parallel, a rich philosophical discussion of the normative aspects of these interactions in social, political and moral philosophy, and in epistemology and metaphysics. The law, taking its cues from these traditions, strives to provide structure to these interactions, and attempts to answer questions such as: What rights do our fellow citizens have? How do we judge them liable for their actions? When do we attribute knowledge to them? How do we assess the quality of their decisions? What sorts of responsibilities can, and should be, assigned to them? My recently released book, A Legal Theory for Autonomous Artificial Agents, (with Laurence F. White, University of Michigan Press, 2011) seeks to take forward these parallel legal and philosophical projects in answer to conundrums posed by artificial agents. In it, we seek to apply and extend existing legal and philosophical theories of personhood, knowledge attribution, agency, responsibility, and liability, to the many roles artificial agents can be expected to play and the legal challenges they will pose while so doing. Concentrating on five interconnected areas: personhood for artificial agents; the attribution of knowledge to them, and to their principals; liability and responsibility of, and for, artificial agents; decision-making by artificial agents; and privacy and artificial agents, and building cumulatively on discussions in each, we ask, what are the legal and philosophical strategies available to us in making room for artificial agents, future residents of our polity and society? Drawing upon both contemporary and classical legal and philosophical analysis, we develop a prescriptive legal theory for the legal, philosophical and technical communities to guide our future interactions with artificial agents.

November 2, 2012

Speaker: Eduardo Fermé (Universidade da Madeira)

Title: AGM-25 years (now 28)

Abstract: The 1985 paper by Carlos Alchourrón (1931–1996), Peter Gärdenfors, and David Makinson (AGM), “On the Logic of Theory Change: Partial Meet Contraction and Revision Functions” was the starting-point of a large and rapidly growing literature that employs formal models in the investigation of changes in belief states and databases. In this talk, the first twenty-five years of this development are summarized. The topics covered include equivalent characterizations of AGM operations, extended representations of the belief states, change operators not included in the original framework, iterated change, applications of the model, its connections with other formal frameworks, and criticism of the model.

October 8, 2012

Speaker: Jonathan Ben-Naim (IRIT - CNRS / Université de Toulouse)

Title: Definitions in Metamath

Abstract: The goal of this work is to state conditions guaranteeing that a definition can be replaced by a certain axiom in the proof verifier Metamath. The main axiomatic system developed in Metamath is (, it is based on a hilbert-style proof system of the Zermelo–Fraenkel set theory, and it contains around 300 definitions and 10000 theorems. A limitation of Metamath is that it is impossible for a user to introduce a definition D in an axiomatic system A. On the other hand, a user can extend the language of A and add a new axiom X. Rougly speaking, a theorem induced by A and D is a formula F such that unfolding F with D yields a theorem of A. In parallel, a theorem generated from A and X is a theorem of A', where A' is the system obtained from A by adding X to the axioms. The goal of this work is to state conditions ensuring that the theorems induced by A and D are exactly those generated from A and X.

October 1, 2012

Speaker: Pietro Galliani (Institute for Logic, Language and Computation, Universiteit van Amsterdam)

Title: On the Extensions of Dependence Logic

Abstract: In this talk, I will present Dependence Logic and I will discuss a number of recent results concerning the classification of extensions and variants of this formalism. I will focus in particular on Grädel and Väänänen's Independence Logic, showing that it can be obtained through many different choices of operators and discussing their doxastic interpretations. Furthermore, I will argue that this logic represents a natural cutoff point in the family of first order logics of imperfect information.

July 13, 2012

Speaker: Samy Soares Sá (Universidade Federal do Ceará, Brazil)

Title: Arguments and Dialogues for Group Decision Making

Abstract: In this talk we will discuss Group Decision Making (GDM) and some current research on applying an argumentation approach for it. The problem of GDM involves combining the individual preferences of several agents into group preferences, such as in Social Choice Theory. Most approaches are established as a function over the set of individual preference orderings and produce another preference ordering meant to represent the opinion of the group. However these suffer from several known inconsistencies. We believe argumentation can improve GDM as agents could try to convince the others about what are the better options (in their own opinion), what would lead for some bad options to be discarded and some individual preferences to be updated. For this purpose, we will present Cooperative Dialogues as an important step towards this kind of GDM. In the talk we will therefore discuss some of the basic concepts we have already conceived, the next steps of our research, and some challenges to the current approach.

June 28, 2012

Speaker: Valentin Goranko (Technical University of Denmark)

Title: Preplay negotiations in non-cooperative games (joint work with Paolo Turrini)

Abstract: I will present an extension of strategic normal form games with a phase of negotiations before the actual play of the game, where players can make binding offers for transfer of utilities to other players after the play of the game, in order to provide incentives for each other to play designated strategies. Offers are conditional on the recipients playing the specified strategies and they effect transformations of the payoff matrix of the game by accordingly transferring payoffs between players. I will discuss solution concepts for 2-player normal form games with such preplay offers under various assumptions for the preplay negotiation phase and will mention some results for existence of efficient negotiation strategies of both players. Time permitting, I will then discuss extensions of the framework to coalitional preplay offers in N-player games, as well as to extensive form games with inter-play offers for side payments.

June 18, 2012

Speaker: Matthias Thimm (University of Koblenz)

Title: Classification and Strategical Issues of Argumentation Games on Structured Argumentation Frameworks

Abstract: This talk deals with strategical issues of arguing agents in a multi-agent setting. We investigate different scenarios of such argumentation games that differ in the protocol used for argumentation, i. e. direct, synchronous, and dialectical argumentation protocols, the awareness that agents have on other agents beliefs, and different settings for the preferences of agents. We give a thorough investigation and classification of these scenarios employing structured argumentation frameworks which are an extension to Dung's abstract argumentation frameworks that give a simple inner structure to arguments. We also provide some game theoretical results that characterize a specific argumentation game as strategy-proof and develop some argumentation selection strategies that turn out to be the dominant strategies for other specific argumentation games.

June 12, 2012: Stochastic Meeting

Speaker: Giovanni Peccati (University of Luxembourg)
Title: On probabilistic approximations
Abstract: Motivated by some problems in cosmological data analysis, I will discuss some recent results concerning probabilistic approximations and related convergence theorems. Connections with the notions of concentration and universality will be also discussed.

Speaker: Felix Norman Teferle (University of Luxembourg)
Title: Noise characterization in geodetic time series: Maximum Likelihood Estimation and Monte Carlo Markov Chain Methods

Speaker: Tanja Schiling (University of Luxembourg)
Title: Monte Carlo Simulation in Soft Condensed Matter Physics
Abstract: We present an introduction into Monte Carlo simulation as it is used in soft matter physics, and, in particular to predict materials properties of simple model systems such as hard colloidal particles. As examples we will show recent results on percolation in suspensions of anisotropic particles and on the freezing transition in suspesnions of hard spheres.

June 1, 2012

Speaker: Joanna Kolodziej (University of Bielsko-Biala)

Title: Genetic Search Reinforced by the Population Hierarchy: Hierarchic Genetic Strategy (HGS)

Abstract: As a result of their ability to deliver high quality solutions in reasonable time, Meta-heuristics are usually employed as effective methods to solve the complex multi-objective optimization problems. One class of such meta-heuristics is Hierarchic Genetic Strategy (HGS). A Genetic Algorithm variant, HGS differs from other genetic methods in its capability of searching concurrently the solution space. The HGS efficiency is therefore produced by the simultaneous execution of many dependent evolutionary processes. Every single process is then interpreted as the branch in a tree structure and can be defined as a sequence of evolving populations. The overall dependency relation among processes has a restricted number of levels. In this talk we present the theoretical and experimental evaluation of HGS in solving various complex multi-objective optimisation problems in discrete and continuous domains. In particular, the application of the strategy in scheduling the independent tasks in Computational Grids under various criteria like the time and budget constraints, energy consumption, security scheduling, is highlighted.

Short Bio: Dr Joanna Kolodziej graduated in Theoretical Mathematics from the Jagiellonian University in Cracow (Poland) in 1992, where she also obtained the PhD in Theoretical Computer Science in 2004. She is an associate professor at the Department of Mathematics and Computer Science of the University of Bielsko-Biala (Poland), which she joined in 1997. Evolutionary computation, modelling of stochastic processes, Grid computing and global optimization meta-heuristics are the main topics of her research. She has served and is currently serving as PC Co-Chair, General Co-Chair and IPC member of several international conferences and workshops including PPSN 2010, ECMS 2009-12, CISIS 2011, 3PGCIC 2011, CISSE 2006, CEC 2008, IACS 2008-2009, ICAART 2009-2010. Dr Kolodziej has been awarded for the best MSD Thesis in Theoretical Mathematics by Polish Mathematical Society in 1992 and for the best PhD Thesis in Computer Science, Physics and Mathematics by The Foundation for Polish Science in 2004. She has published in international journals, books and conference proceedings of the research area. She is Managing Editor of IJSSC Journal and serves as a EB member and guest editor of several peer-reviewed international journals.

May 21, 2012

Speaker: Francois Schwarzentruber (ENS Cachan/Bretagne)

Title: One hour trip in the STIT fragments countryside

Abstract: We provide a Kripke semantics for a STIT logic with the 'next' operator. As the atemporal group STIT is undecidable and unaxiomatizable, we are interested in strict fragments of atemporal group STIT. First we prove that the satisability problem of a formula of the fragment made up of individual coalitions plus the grand coalition is also NEXPTIME-complete. We then generalize this result to a fragment where coalitions are in a given lattice. We also prove that if we restrict the language to nested coalitions the satisability problem is NP-complete if the number of agents is fixed and PSPACE-complete if the number of agents is variable. Finally we embed individual STIT with the 'next' operator into a fragment of atemporal group STIT.

May 9, 2012

Speaker: Koen Hindriks (Delft University of Technology)

Title: Agent Programming in GOAL

Abstract: I will introduce and discuss the main concepts of the rule-based agent programming language GOAL (beliefs, goals, rules, and modules), discuss how these agents interact with environments (action and percepts), and communication in a multi-agent system. I'll also present various examples of environments, including classic AI toy problems such as the Blocks and Wumpus World, games such as UT, and robots.

May 2, 2012

Speaker: Marek Bednarczyk (Polish Academy of Sciences)

Title: Hypernets: a formalism to model and reason about mobility

Abstract: The purpose of the talk is to present some results and directions of research in the area of mobility. In particular we present the idea of hypernets in which agents supervise the activities of other agents in hierarchical manner.

The model is based in Petri nets, i.e., an agent is a Petri net. Thus, the formalism falls within the ,,nets-within-nets'' group of frameworks. This has distinctive advantages: under certain assumptions one can translate a hypernet, even with agent creation allowed, to a finite P/T net system with isomorphic state space. Thus, certain important properties, like reachability of a state from a given one, are decidable, although at very high cost. Since non-trivial fragments of temporal logics tend to have undecidable model-checking problem one is also tempted to turn to Petri nets which support invariant analysis as a method to verify interesting properties of systems with possibly infinite state spaces.

April 20, 2012

Speaker: Pierre Manneback (Polytech-Mons)

Title: Exploitation of Parallel Heterogeneous Architectures for multimedia processing

Authors: Sébastien Frémal, Sidi Ahmed Mahmoudi, Pierre Manneback

Abstract: Computers consist mainly on two kinds of processors: Central Processor Unit (CPU) and Graphics Processor Unit (GPU). CPUs are used in personal computers as the main processing unit. GPUs were introduced in the late 1990s to assist central processors in display operations. Moreover, they can be used for accelerating different applications by applying parallel treatments on massive amount of data. Furthermore, there are computers composed of multiple CPUs and GPUs presenting heterogeneous architectures. More particularly, image and video processing algorithms can benefit from these platforms by exploiting effectively their computing units in parallel. We propose a general framework for multimedia processing on parallel (GPU) and heterogeneous architectures. This framework is based on exploiting the full computing power of hybrid platforms (Multi-CPU/Multi-GPU). The proposed framework enables to select firstly the computing units (CPU or/and GPU) for processing, and secondly the methods to be applied depending on the type of media to treat. Indeed, we employ an efficient scheduling strategy based on the history of the computing times of precedent tasks. We exploit also CUDA streams in order to overlap data transfers by kernels executions within multiples GPUs. Experimentations have been conducted using different types of media (HD images, databases of medical images, HD videos) within different applications. These results showed a global speedup ranging from 10 to 50, by comparison with sequential CPU implementations.

March 26, 2012

Speaker: Nils Bulling (Clausthal University of Technology)

Title: How to Achieve and How to Verify Norm Compliance of Resource-Bounded Agents?

Abstract: The verification and modeling of multi-agent systems is an important topic that has attracted much attention in recent years. Resources, however, have only recently been studied as simple extensions of well-known logics. In this talk I explore the question: Where are the limits of what can be verified about resource-bounded agents? I try to answer this question by considering several natural logic-based settings that may arise and prove that verification is usually undecidable apart from bounded or otherwise restricted settings.

In the second part of my talk, I turn to the question of how agents can be incentivised to comply with the norms of a MAS. I show how concepts from mechanism design can be used to formally analyze and verify whether specific normative behaviors can be enforced (or implemented) if agents follow their subjective preferences.

The behavior of agents strongly depends on available resources (incentives themselves can be seen as resources). Hence, a natural question arises: How to achieve and how to verify norm compliance of resource-bounded agents? I would like to address this question in my future research.

March 12, 2012

Speaker: Artur Meski and Maciej Szreter (Polish Academy of Sciences, Warsaw)

Title: Bounded Model Checking Linear Time and Knowledge Using Decision Diagrams

Abstract: In our talk we are going to present a novel approach to verification of multi-agent systems by bounded model checking for Linear Time Temporal Logic extended with the epistemic component (LTLK), which is interpreted over interleaved interpreted systems. Our method is based on binary decision diagrams that are used for representing the verified system. We describe the algorithm and provide its experimental evaluation together with the comparison with another tool. We also provide an overview of other verification tools for multi-agent systems.

February 27, 2012

Speaker: Francois Schwarzentruber (ENS Cachan/Bretagne)

Title: Tableau Method and NEXPTIME-Completeness of DEL-Sequents

Abstract: Dynamic Epistemic Logic (DEL) deals with the representation of situations in a multi-agent and dynamic setting. It can express in a uniform way statements about: (i) what is true about an initial situation (ii) what is true about an event occurring in this situation (iii) what is true about the resulting situation after the event has occurred. After proving that what we can infer about (ii) given (i) and (iii) and what we can infer about (i) given (ii) and (iii) are both reducible to what we can infer about (iii) given (i) and (ii), we provide a tableau method deciding whether such an inference is valid. We implement it in LOTRECscheme and show that this decision problem is NEXPTIME-complete. This contributes to the proof theory and the study of the computational complexity of DEL which have rather been neglected so far.

February 1, 2012

Speaker: Elad Dokow (Bar Ilan University)

Title: Models of Manipulation on Aggregation of Binary Evaluations

Abstract: We study a general aggregation problem in which a society has to determine its position on each of several issues, based on the positions of the members of the society on those issues. There is a prescribed set of feasible evaluations, i.e., permissible combinations of positions on the issues. Among other things, this framework admits the modeling of preference aggregation, judgment aggregation, classification, clustering and facility location. An important notion in aggregation of evaluations is strategy-proofness. In the general framework we discuss here, several definitions of strategy-proofness may be considered. We present here 3 natural general definitions of strategy-proofness and analyze the possibility of designing an annonymous, strategy-proof aggregation rule under these definitions. (Joint work with Dvir Falik)

January 25, 2012

Speaker: Malgorzata Sterna (Poznan University of Technology)

Title: Late Work Scheduling Problems

Abstract: We present scheduling problems with the late work criteria - non classical performance measures. Late work objective functions estimate the quality of a schedule based on durations of late parts of jobs, not taking into account the amount of delay for fully late jobs. We provide a formal definition of the late work parameter and compare the criteria based on it with other classical performance measures. Moreover, a few real world applications of the late work objective function are given. Then we present selected results obtained for late work scheduling problems with a single machine, parallel and dedicated machines.

Malgorzata Sterna earned Master degree in Computer Science (Distributed Computer Systems) at Poznan University of Technology in 1996. At the same University, she got Ph.D. degree and Habilitation in Computer Science (Scheduling Theory, Theory of Algorithms) in 2000 and 2007 respectively. Malgorzata Sterna is an assistant professor at the Faculty of Computing and Information Science at Poznan University of Technology and associate professor at the Institute of Computing Science at State Higher Vocational School in Gniezno. Her fields of interest include scheduling theory, complexity theory, algorithms design, selected aspects of graph theory, combinatorial optimization and bioinformatics. Malgorzata Sterna got the stipend of the Foundation for Polish Science in 2000 and award of the Polish Academy of Sciences from the IV Division of Technical Sciences in the field of Computer Science in 2008. She has collaborated with Université Joseph Fourier (Grenoble), Otto-von-Guericke-Universitat (Magdeburg), Universitat Bonn, Autonomous University of Baja California (Tijuana) and University of Nottingham. Malgorzata Sterna is a reviewer for 14 journals from ISI Master Journal List and for the Polish Ministry of Science and Higher Education. She is a member of Polish Accreditation Committee.

January 23, 2012

Speaker: Jean-Yves Beziau (Universite de Neuchatel)

Title: The Power of the Hexagon

Abstract: In this lecture I will present and discuss the hexagon of opposition, an improvement of the square of opposition due to Robert Blanche. The hexagon of Blanché is made of a triangle of contrariety and a triangle of subcontrariety linked together by the relations of contradiction and subalternation. This hexagon includes the traditional square and can be extended to three dimensional objects giving a better understanding of modalities and negations. I will also show how this simple logical structure based on three oppositions can be applied to many different concepts ranging from logic to music, through metalogic, economy and semiotics.

Decemember 8, 2011 (joint ILIAS/SRM seminar)

Speaker: Laurent Doyen (CNRS Cachan)

Title: Partial-Observation Stochastic Games: How to Win when Belief Fails

Abstract: We consider two-player stochastic games played on finite graphs with reachability (and Buechi) objectives where the first player tries to ensure a target state to be visited (or visited infinitely often) almost-surely, i.e., with probability 1, or positively, i.e., with positive probability, no matter the strategy of the second player.

We classify such games according to the information and to the power of randomization available to the players. On the basis of information, the game can be one-sided with either (a) player 1, or (b) player 2 having partial observation, or two-sided with (c) both players having partial observation.

On the basis of randomization, (a) the players may not be allowed to use randomization (pure strategies), or (b) they may choose a probability distribution over actions but the actual random choice is external and not visible to the player (actions invisible), or (c) they may use full randomization.

Our main results for pure strategies are as follows: (1) For one-sided games with player 2 perfect observation we show that (in contrast to full randomized strategies) belief-based strategies are not sufficient, and we present an exponential upper bound on memory both for almost-sure and positive winning strategies; we show that the problem of deciding the existence of almost-sure and positive winning strategies for player 1 is EXPTIME-complete. (2) For one-sided games with player 1 perfect observation we show that non-elementary memory is both necessary and sufficient for both almost-sure and positive winning strategies. (3) We show that for the general (two-sided) case finite-memory strategies are sufficient for both positive and almost-sure winning, and at least non-elementary memory is required.

We establish the equivalence of the almost-sure winning problems for pure strategies and for randomized strategies with actions invisible. Our equivalence result exhibits serious flaws in previous results in the literature: we show a non-elementary memory lower bound for almost-sure winning whereas an exponential upper bound was previously claimed.

September 19, 2011

Speaker: Chiaki Sakama (Wakayama University, Japan)

Title: A Logical Account of Lying

Abstract: The current work aims at providing a formal account of lying - a dishonest attitude of human beings. We first formulate lying under propositional modal logic and present basic properties for it. We then investigate why one engages in lying and how one reasons about lying. We distinguish between offensive and defensive lies, or deductive and abductive lies, based on intention behind the act. We also study two weak forms of dishonesty, bullshit and deception, and provide their logical features in contrast to lying. We finally argue dishonesty postulates that agents should try to satisfy for both moral and self-interested reasons. (Joint work with Martin Caminada and Andreas Herzig.)

About the speaker: Chiaki Sakama graduated from Kyoto University in 1985 and received a Dr. Eng. degree in computer science in 1995. He worked at Toshiba and joined the Fifth Generation Computer Project in Japan. He has been at Wakayama University since 1995 and is currently a Professor in the Department of Computer and Communication Sciences. He has been engaged in research on logic programming, nonmonotonic reasoning, and machine learning. His recent research interests involve in theoretical foundations of multiagent systems and social intelligence.

July 1, 2011

Speaker: Llio Humphreys (University of Turin)

Title: Eunomos, a legal document management system based on legislative XML and ontologies

Abstract: This talk will discuss the ongoing work and future developments on the Eunomos software, an advanced legal document management system that enables users to research laws and legal concepts, and make sure they comply with their legal obligations. Eunomos is based on legislative XML representation of laws which are retrieved automatically from institutional legislative portals, and is complemented by a tool for building legal ontologies called Legal Taxonomy Syllabus. The software can help law firms, in-house legal offices and law scholars by offering them an environment which makes laws easier to navigate, annotate and understand, using automatically generated hyperlinks to referenced legislation, an extensible and updatable ontology which provides current and previous definitions for norms and concepts within any specific context, and an alert system that specifies existing legislation affected by new legislation. It is intended that the system will be used in the first instance by banks and insurance companies to help them comply with strict regulatory duties in a highly complex and constantly evolving area of law.

May 23, 2011

Speaker: Srdjan Vesic (IRIT Toulouse)

Title: A New Approach for Preference-Based Argumentation Frameworks

Abstract: Dung's argumentation framework consists of a set of arguments and an attack relation among them. Arguments are evaluated and acceptable sets of them, called extensions, are computed using a given semantics. In the literature, several proposals have extended this framework in a way to take into account the strength of arguments. The basic idea is to ignore an attack if the attacked argument is stronger than (or preferred to) its attacker. Semantics are then applied using only the remaining attacks.

In this talk, we show that those proposals behave correctly when the attack relation is symmetric. However, when it is asymmetric, conflicting extensions may be returned leading to unintended conclusions. We propose an approach that guarantees conflict-free extensions. This approach presents two novelties: the first one is that it takes into account preferences at the semantics level rather than the attack level. The idea is to extend existing semantics with preferences. In case preferences are not available or do not conflict with the attacks, the extensions of the new semantics coincide with those of the basic ones. The second novelty of our approach is that a semantics is defined as a dominance relation on the power set of the set of arguments. The extensions (under a semantics) are the maximal elements of a dominance relation. Such an approach allows not only to compute the extensions of a framework but also to compare its non-extensions.

We start by proposing three dominance relations that generalize respectively stable, preferred and grounded semantics with preferences. Then, we focus on stable semantics and provide a full characterization of its dominance relations and that of its generalized versions. Complexity results are also provided. Finally, we show that an instance of the proposed framework retrieves the preferred sub-theories which were proposed in the context of handling inconsistency in weighted knowledge bases.

April 28, 2011

Speaker: Nan Li (Autonomous University of Barcelona)

Title: A Liberal Impossibility of Abstract Argumentation

Abstract: In abstract argumentation, where arguments are viewed as abstract entities with a binary defeat relation among them, a set of agents may assign individual members the right to determine the collective defeat relation on some pairs of arguments. I prove that even under a minimal condition of rationality, the assignment of rights to two or more agents is inconsistent with the unanimity principle, whereby unanimously accepted defeat or defend relation among arguments are collectively accepted. This result expands the domain of liberal impossibility beyond preference aggregation and judgment aggregation, and highlights this impossibility as an inherent tension between individual rights and collective consensus.

April 4, 2011

Speaker: Henning Schnoor (University of Kiel)

Title: Epistemic, Probabilistic ATL* with an Application to Security

Abstract: ATL(*) is a well-established logic to reason about strategic properties of games. Recently, epistemic variations of ATL have been introduced that take into account that players in games often only have partial information on which they can base their decisions, and in addition allow to explicitly express knowledge-based properties of games. Additionally, extensions of ATL to probabilistic contexts have been investigated.

We present QAPI, a new variant of ATL which incorporates the above features, and allows explicit reasoning about strategies in the object language. This leads to a very expressive logic that can express complex strategic properties as equilibria. We obtain bisimulation relations and model checking complexity results.

As application, we show how to use QAPI to express security properties of state-observed systems as well as cryptographic protocols. This implies new decidability results in cryptographic protocol verification.

March 14, 2011

Speaker: Paolo Turrini (Utrecht University)

Title: Turning competition into cooperation and cooperation into competition

Abstract: The present talk discusses the classical problem of transforming a strategic game into a cooperative one and answers two questions:

1) can strategic games be characterized in terms of cooperative ones?
2) are there alternative ways to build up cooperative interactions from strategic ones?

The first part of the talk, result of joint work with Wojtek Jamroga and Valentin Goranko, revisits the issue of correspondence between strategic games, objects of study of noncooperative game-theory, and effectivity functions, object of study of cooperative game theory. The second one, result of joint work with Davide Grossi, proposes a new approach to cooperative interaction, where players cooperate only in presence of an appropriate interdependence. The resulting structures can be nicely analyzed with classical tools.

March 11, 2011

Speaker: Rohit Parikh (City University of New York)

Title: The Logic of Campaigning (joint work with Walter Dean)

Abstract: There is a great deal of existing work on changes in belief states when a public announcement is made. How is this work relevant to campaigning? In the US, while a presidential election typically takes a single day, the processs of campaigning starts more than a year in advance, with various candidates trying to influence public opinion. We offer a simple propositional logic based model for this process. We assume that the various issues are represented by certain propositions which may become true or false as the result of a particular candidate becoming elected. We also assume that various groups of voters of different sizes have wishes as to whether they want a particular proposition to be true or false and who also have a degree of passion for each such proposition representing how much they care. The candidate has already made some statements indicating how she will act if elected but her positions on some issues may be unclear. How should she speak now in order to increase her chances of being elected?

March 11, 2011

Speaker: Nicolas Troquard (University of Essex)

Title: Logics of agents with small models

Abstract: Possible worlds and relational semantics are commonly used to model multi-agent systems. However, describing a complex system in terms of possible worlds is often unpractical. For instance, in MOCHA (a model checker for ATL), reactive modules are used to overcome this difficulty: the powers of agents and coalitions are derived from the ability to control some variables. In this talk, I will provide evidences that interesting logics with small models are attainable for a variety of notions: coalitional ability, dynamicity and imperfect information.

Coalition Logic of Propositional Control (CL-PC) (van der Hoek & Wooldridge 2005), whose models are directly inspired by reactive modules, is an example of logics of agents with small models. I will also present Dynamic Logic of Propositional Assignments (DL-PA) that is evaluated wrt. simple propositional models. I will show how DL-PA can simulate CL-PC. Finally, time permitting, I will present one or two epistemic variants of CL-PC. Axiomatisations, and complexities of model checking and satisfiability checking will be discussed.

Contains joint work with Wiebe van der Hoek, Michael Wooldridge (epistemic CL-PC) and Andreas Herzig (DL-PA).

February 14, 2011

Speaker: Ulle Endriss (University of Amsterdam)

Title: Complexity of Judgment Aggregation

Abstract: Aggregating the judgments of a group of agents regarding a set of interdependent propositions, expressed in propositional logic, can lead to inconsistent outcomes. This paradox of judgment aggregation has recently sparked a good deal of interest in Legal Theory, Philosophy, Economics, Logic, and Computer Science. In this talk, I will first give a short introduction to judgment aggregation and then report on our ongoing work aimed at better understanding this problem domain from a computational point of view. Specifically, we have analysed the computational complexity of several problems that naturally arise in the context of judgment aggregation: computing a collective judgment, strategic manipulation, and deciding whether a given class of aggregation problems can be guaranteed not to lead to paradoxical outcomes. This is joint work with Umberto Grandi and Daniele Porello. I will explain how this work fits into the broader research agenda of Computational Social Choice (COMSOC).

February 23, 2011

Speaker: Pierre Del Moral (INRIA Bordeaux Sud-Ouest/IMB, France)

Title: Concentration inequalities for mean field particle models (joint work with Emmanuel Rio)

Abstract: This lecture is concerned with the fluctuations and the concentration properties of a general class of discrete generation and mean field particle interpretations of non linear measure valued processes. We combine an original stochastic perturbation analysis with a concentration analysis for triangular arrays of conditionally independent random sequences, which may be of independent interest. Under some additional stability properties of the limiting measure valued processes, uniform concentration properties with respect to the time parameter are also derived. The concentration inequal ities presented here generalize the classical Hoeffding, Bernstein and Bennett inequalities for independent random sequences to interacting particle systems, yielding very new results for this class of models. We illustrate these results in the context of McKean Vlasov type diffusion models, McKean collision type models of gases, and of a class of Feynman-Kac distribution fl ows arising in stochastic engineering sciences and in molecular chemistry.

January 12, 2011

Speaker: Tom Gordon (Fraunhofer Institute Berlin)

Title: The Carneades Argumentation System

Abstract: Carneades is an argument mapping and analysis application, with a graphical user interface, and a software library for building applications supporting various argumentation tasks. Carneades provides tools supporting a variety of argumentation tasks, including:

Carneades will be demonstrated using a prototype application for helping software developers to analyse Open Source licensing issues, which was developed in the European Qualipso project. The presentation will focus on the underlying computational model of argument.

November 22, 2010

Speaker: Mustafa Ali Turker (Middle East Technical University Ankara)

Title: Mindful Evolution

Abstract: Let's define an evolutionary process as varying and assessing options on the face of challenges, selecting and expressing the choice, repeating this until a solution construct emerges. It readily follows that a good many collective and cognitive processes fits to this description. However random the choice outcomes may be, only in retrospect their totality is recalled as one meaningful narrative: a consistent chain of causal events. Could it be possible to improve such processes while experiencing them? How can evolution be improved at all while control points are spread wide, internally and externally? Autonomous learning is one such evolutionary cognitive process, where the variety of options increased dramatically thanks to the Web and ICT support. In this seminar, we will dicuss how can the evolutionary flow of the study experience be objectifed using phenomenological principles. A spatio-temporal computer visualisation will be proposed to mediate the flow on-the-fly. The learner can mindfully appraise the construct towards which the flow is currently oriented; guide and redirect. Cognitive Dimensions of Notations framework is used to evaluate the resulting increase in affordance.

October 27, 2010

Speaker: Inanc Seylan, University of Bozen/Bolzano

Title: Proving Interpolation in Description Logics Using Mosaic and Axiom Instantiation Techniques

Abstract: Many description logics have the tree model property, i.e., satisfiable concepts always admit tree shaped models. In this talk I will first show how to draw trees using small but meaningful pieces called mosaics. Then I will use the mosaic and axiom instantiation techniques to prove polynomial reductions from more expressive description logics to less expressive ones. Finally I will discuss how these reductions can be used to prove interpolation theorems. Interpolation itself has applications in query rewriting over databases using ontologies, obtaining acyclic TBoxes from general ones, and signature decompositions.

October 21, 2010

Speaker: David Makinson, London School of Economics

Title: Intuitionistic logic, elementary rules, classical logic

Abstract: The interplay of introduction and elimination rules for the propositional connectives is often seen as suggesting a distinguished role for intuitionistic logic in preference to classical. We prove a formal result that helps clarify this perspective: intuitionistic consequence is the least consequence relation over a suitable language that satisfies all classically correct elementary rules, and discuss its significance. (joint work with Lloyd Humberstone, Monash)

October 18, 2010

Speaker: David Makinson, London School of Economics

Title: Proto-probability functions

Abstract: In recent years, the study of qualitative uncertain inference has given rise to the notion of probabilistically sound consequence relations. They are rather like preferential consequence relations in that they may fail monotony, but satisfy only conditions that are, in a natural sense, probabilistically sound. A syntactic account was given by Hawthorne, although the question of its completeness remains open. The study of such consequence relations leads naturally to a generalization of existing accounts of conditional probability itself, such as the standard ratio/unit definition and the less well known intrinsically conditional systems of Hosiasson-Lindenbaum, Popper, and van Fraassen. The idea is to articulate a weakest notion of conditional probability that suffices to validate the postulates of Hawthorne's system for probabilistic consequence. We do this in purely-order theoretic terms, calling it proto-probability, and begin a study of its behaviour.

September 29, 2010

Speaker: Chattrakul Sombattheera, Mahasarakham University

Title: Optimal Coalition Structure in Humanoid Robots

Abstract: Optimal coalition structure has gained much attention in multi-agent systems research recently. The problem itself is more of an optimization problem but is also an important ingredient in solving multiple research problems in multi-agent systems. The problem is known an NP-hard problem. The research on the problem so far has focuses on the theoretical part and assumes some certain computational power. It is a challenge to solve this problem in bounded-rational agents, as in humanoid robots.

This talk will present an attempt to bridge the theory background of the problem, which is mainly what I have done in my thesis, and the practical world as in "Nao" humanoid robots. The first part will be how can we solve the problem in characteristic function game. The second part is solving the problem in more practical domains, including linear, non-linear and supply chains. The last part will be the on-going work here in Luxembourg: solving the problem in humanoid robots.

September 8, 2010

Speaker: Nils Bulling, Clausthal University of Technology

Title: On the Complexity of Verifying Agents With and Without Memory: A Comparison

Abstract: In this talk I give an overview of the model checking problems for various strategic logics. Besides the standard logics ATL and ATL*, we discuss ATL+ and show that it is the minimal well-known fragment for which model checking under the perfect recall semantics is harder than for the memoryless semantics. We prove that the model checking problem for this logic under perfect recall is PSPACE-complete.

July 26, 2010

Speaker: Artur d'Avila Garcez

Title: Neurosymbolic Cognitive Computation

Abstract: Three notable hallmarks of intelligent cognition are the ability to draw rational conclusions, the ability to make plausible assumptions, and the ability to generalise from experience. Although human cognition often involves the interaction of these three abilities, in artificial intelligence they are typically studied in isolation. In our research programme, we seek to integrate the three abilities within neural computation, offering a unified framework for learning and reasoning that exploits the parallelism and robustness of connectionism. A neural network can be the machine for computation, inductive learning and effective reasoning, while logic provides rigour, modularity and explanation capability to the network. We call such systems, combining a connectionist learning component with a logical reasoning component, "neural-symbolic learning systems". In this talk, I review the work on neural-symbolic learning systems, starting with logic programming, which has already provided contributions to problems in bioinformatics and engineering. I then look at how to represent modal logic and other forms of non-classical reasoning in neural networks. The model consists of a network ensemble, each network representing the knowledge of an agent at a time-point. Networks can be combined to represent and learn relations between objects, with interesting potential applications in graph mining and link analysis in biology and social networks. We claim that this powerful yet simple structure offers a basis for an expressive and computationally tractable cognitive model.

July 1, 2010

Speaker: Mehdi Dastani (Utrecht University)

Title: Strategic Executions of Choreographed Timed Normative Multi-Agent Systems

Abstract: This talk presents a combined mechanism for coordinating agents in timed normative multi-agent systems. Timing constraints in a multi-agent system make it possible to force action execution to happen before certain time invariants are violated. In such multiagent systems we achieve coordination at two orthogonal levels with respect to states and actions. On the one hand, the behaviour of individual agents is regulated by means of social and organisational inspired concepts like norms and sanctions. On the other hand, the behaviour of sets of agents is restricted according to action-based coordination mechanisms called choreographies. In both cases, the resulting behaviour is constrained by time.

July 1, 2010

Speaker: Koen Hindriks (TU Delft)

Title: Preference Reasoning

Abstract: We are interested in qualitative models of preferences in the context of negotiation. We are after a preference framework that supports reasoning with multiple issues and that is able to handle incomplete information. In this talk I present an argumentation-based framework for the modeling of and automated reasoning about multi-issue preferences of a qualitative nature. The framework presents preferences according to the lexicographic ordering that is both intuitive and well-understood by humans. We discuss some of the issues involved when only incomplete information about preferences is available. We then proceed and discuss a second issue related to incomplete information, namely the absence of objective knowledge from which preferences are derived.

June 24, 2010

Speaker: Olivier Pietquin (Supelec, Metz)

Title: Information, Multimodality and Signals

Abstract: In this talk will be presented the research activities of the Supelec's IMS group. Supelec is an French engineering school based on 3 campuses (Gif-sur-Yvette, Metz, Rennes) and IMS is one of the two research groups of its Metz campus. IMS focuses its research on a situated approach to information processing. This approach mixes signal processing, machine learning and distributed computing and aims at building autonomous machines. IMS applies its research to robotics, man-machine interfaces and intelligent environments. After a general presentation of the group's research activities, the talk will focus on typical applications and projects in which IMS is currently involved. We expect this talk to be an opportunity for fruitful discussions.

Olivier Pietquin obtained an Electrical Engineering degree from the Faculty of Engineering, Mons (FPMs, Belgium) in June 1999 and a PhD degree in April 2004. He joined the FPMs Signal Processing department (TCTS Lab.) in September 1999. In 2001, he has been a visiting researcher at the Speech and Hearing lab of the University of Sheffield (UK). Between 2004 and 2005, he was a Marie-Curie Fellow at the Philips Research lab in Aachen (Germany). Now he is an Associate Professor at the Metz campus of Supelec (France), and heads the "Information, Multimodality & Signal" (IMS) research group. His research interests include spoken dialog systems evaluation, simulation and automatic optimisation, machine learning as well as image, multimedia and biomedical signal processing.

June 21, 2010

Speaker: Valentin Goranko (Technical University of Denmark, Copenhagen)

Title: A Logical Framework for Capturing the Dynamics of Information and Abilities of Players in Multi-Player Games (joint work with Peter Hawke)

Abstract: I will discuss first steps towards a more realistic treatment and logical formalization of the abilities of players to achieve objectives in multi-player games under incomplete, imperfect, or simply wrong information that they may have about the game and about the course of the play. In this talk, after some motivating examples I will introduce a variation of the multi-agent logic ATL as a logical framework for capturing the interplay between the dynamics of information and the dynamics of abilities of players. This framework takes into account both the a priori information of players with respect to the game structure and the empirical information that players develop over the course of an actual play. It associate with them respective information relations and notions of `a priori' and `empirical' strategies and strategic abilities. I will discuss the problem of model checking of statements formalized in the new logic under different assumptions about the abilities of the players to observe, remember, and reason.

June 17, 2010

Speaker: Célia Pereira (University of Milano)

Title: An Integrated Possibilistic Framework for Goal Generation in Cognitive Agents

Abstract: In this talk I will present an integrated theoretical framework, grounded in possibility theory, to account for all the aspects involved in representing and changing beliefs, representing and generating justified desires, and selecting goals based on current and uncertain beliefs about the world, and the preferences of the agent. Beliefs and desires of a cognitive agent are represented as (two distinct) possibility distributions. In such a framework: (i) the possibility distribution representing the qualitative utilities associated with desires are the result of a rule-based deliberative process, that is, they depend on the mental state of the agent and are not given a priori; and (ii) the criteria for choosing goals take into account not only the fact that goals must be consistent in the logical sense, but also in the cognitive sense.

June 14, 2010

Speaker: Sujata Ghosh (University of Groningen)

Title: On strategy composition and game composition

Abstract: We argue that it is useful to reason not only about the existence of strategies for players (in reasoning about games), but also about what these strategies are, and how players select and construct them. We study extensive form games and suggest that this can be carried out in two ways: one by considering a single game, and studying composition of ``local'' strategies; the other, by looking at the compositional structure of a given game (in terms of subgames) and associating strategies that are ``global'' within these subgames. In each case, we study a propostional modal logic in which such reasoning is carried out, and present complete axiomatizations of valid formulas.

June 10, 2010

Speaker: Paolo Turrini (Utrecht University)

Title: Dependence Theory via Game Theory

Abstract: The talk will discuss the relation between two independent research threads in the study of social interaction within multiagent systems: Game Theory and Dependence Theory. While the former lies on solid mathematical foundations, for the latter several informal accounts exist, but no unified formal theory. It will be maintained that the fundamental relation of Dependence Theory, "agent i depends on agent j for the realization of goal p", can be given a natural gametheoretical semantics. Most importantly, it will be observed how cycles arising from dependence relations and equilibrium outcomes in games can be related. This allows for the study of 'agreements', structural transformations of the strategic interaction, that 'solve' dependence relations, giving rise to a new class of coalitional games. The unification presented provides Dependence Theory with the sort of mathematical foundations which still lacks, and shows how Game Theory can incorporate dependence-theoretic considerations in a fully formal manner. The talk is based on joint work with Davide Grossi (ILLC, Amsterdam).

May 31, 2010

Speaker: Nicolas Schwind (Universite d'Artois)

Title: Merging Qualitative Constraint Networks Using Propositional Logic

Abstract: Spatial or temporal reasoning is an important task for many applications in Artificial Intelligence, such as space scheduling, navigation of robots, geographic information systems, computer vision, planification. Several qualitative approaches have been proposed to represent spatial and temporal entities and their relations. These approaches consider the qualitative aspects of the relations only, disregarding any quantitative measurement. In some applications, e.g. multi-agent systems, spatial or temporal information concerning a set of objects may be conflicting. In this talk I will highlight the problem of merging spatial or temporal qualitative constraint networks (QCNs). I will present a rational merging procedure which, starting from a set of possibly conflicting QCNs, returns a non-empty set of spatial or temporal information representing the result of the merging. It is based on translations of QCNs into propositional formulas and takes advantage of propositional merging operators.

May 27, 2010

Speaker: Lionel Daniel

Title: Paraconsistent probabilistic reasoning: application to high-level data fusion in multimodal biometrics

Abstract: In multimodal biometrics, data of several biometric sensors (classifiers) must be aggregated to decide on the authenticity of an individual. Such data are usually high-level since most commercial biometric classifiers only provide information at score, ranking, or decision levels. I suggest to fuse these high-level data by applying a theory that deals with contradictory information: paraconsistent probabilistic reasoning. Such a theory can also be applied to problems from voting theory.

Keywords: decision making, paraconsistency, common sense, voting theory.

May 20, 2010

Speaker: Pietro Baroni and Massimiliano Giacomin (University of Brescia)

Title: Attacks to attacks in abstract argumentation

Abstract: Encompassing attacks to attacks is a significant conceptual extension of Dung's abstract argumentation framework motivated by modelling needs in various contexts including reasoning about preferences, coalition formation, meta-argumentation. Several alternative approaches to encompassing attacks to attacks in abstract argumentation have been recently proposed in the literature. By reviewing and comparing these proposals, the talk aims at presenting a general perspective and technical analysis on the main conceptual and formal issues related to encompassing attacks to attacks in abstract argumentation.

April 29, 2010

Speaker: Thomas Ågotnes (University of Bergen)

Title: Group Announcements: Logic and Games

Abstract: Public announcement logic is used to reason about the epistemic pre- and post-conditions of actions in the form of public announcements. In the first part of the talk I will present Group announcement logic (GAL), an extension of public announcement logic with constructs (well known from coalition logic) of the form phi, where G is a group of agents. In GAL, the meaning of phi is that there exists an announcement that the members of G can jointly and truthfully make, and after that announcement is made public phi will be true. After introducing GAL I will discuss how it can be used to express properties such as "there is a sequence of truthful public announcements by agents in G, after which phi is true"; the distinction between "agent i knows *that* phi can be achieved by a public announcement" and "agent i knows *how* phi can be achieved by a public announcement"; and meta-logical properties such as axiomatisation, expressivity and the complexity of the model checking problem. In the second part of the talk I will discuss the question of which announcements the agents actually will make, assuming that they are rational. I consider situations where each agent has a goal in the form of a (typically epistemic) formula that she would like to become true (e.g., Bob learns my secret without Cat learning it). What will each agent announce, assuming common knowledge of the situation? The truth of the goal formula after the agent's announcement depends on the announcements made by other agents, hence we have a game theoretic scenario.

April 19, 2010

Speaker: Nick Tinnemeier (Utrecht University)

Title: Programming Norm Change

Abstract: Computational frameworks using normative concepts (e.g. obligations and prohibitions) have been widely adopted for regulating the observable behavior of (software) agents. To adequately deal with the unpredictable and dynamic environments these normative frameworks are typically deployed in, mechanisms for modifying the norms at runtime are crucial. In this talk I present the syntax and operational semantics of generic programming constructs to facilitate runtime norm modification, allowing a programmer to specify when and how the norms may be changed by external agents or by the normative framework. In particular, I present rule-based constructs for runtime modification of the norms (conditional obligations and prohibitions), the detached obligations and prohibitions they instantiate (norm instances), and a mechanism for automatically updating the instances when their underlying norms change.

April 1, 2010

Speaker: Eric Pacuit (University of Tilburg)

Title: Revising Intentions and Beliefs

Abstract: While there is an extensive literature developing logical models to reason about informational attitudes (e.g. belief, knowledge, certainty) in a dynamic environment, other mental states have received relatively less attention. (A notable exception here is work on logics of preferences and preference change.) However, this is changing with recent articles developing a theory of intention revision (see, for example, two recent articles: Towards a Theory of Intention Revision by van der Hoek, Jamroga and Wooldridge and A Logic of Intention and Attempt by Lorini and Herzig). These papers take as a starting point logical frameworks derived from Cohen and Levesque's seminal paper aimed at formalizing Bratman's planning theory of intention. In this talk, I will discuss a number of recent dynamic logics of intention and beliefs. In the process we will reexamine a number of foundational issues surrounding so-called BDI-logics.
I will also discuss a recent paper on ``joint revision of belief and intention" (with Yoav Shoham and Thomas Icard) where we present a formal semantical model to capture action, belief and intention, based on the “database perspective” of (Logical Theories of Intention and the Database Perspective, Journal of Philosophical Logic, 2009, by Yoav Shoham). We provide postulates for belief and intention revision, and state a representation theorem relating our postulates to the formal model. Our belief postulates are in the spirit of the AGM theory; the intention postulates stand in rough correspondence with the belief postulates.

March 26, 2010

Speaker: Pablo Noriega (Artificial Intelligence Research Institute)

Title: mWater as a normative MAS

Abstract: The "mWater" system is a demonstrator of the Spanish "Agreement Technologies" (AT) project currently in construction. The problem domain is the normative aspects that affect water demand in a basin. In particular, the trading of water usage rights and the conflicts associated with trading and exploitation of those rights. We are currently designing the ground institutional framework where exchange of rights and conflicts may take place. The objective is to establish and implement the constitutive conventions (and the ground domain ontology) of a normative MAS. The purpose of this MAS is to provide AT researchers with a convenient virtual environment, where several activities may be regulated in different ways, conducive to a rich interplay between theoretical and engineering issues associated with agreement topics. My presentation would be a description of the framework and an exploration of normative issues that might be interesting to address.

March 11, 2010

Speaker: Francesca Toni (Imperial College)

Title: Combining statistics and arguments to compute trust

Abstract: We propose a method for constructing Dempster-Shafer belief functions modeling the trust of a given agent (the evaluator) in another (the target) by combining statistical information concerning the past behaviour of the target and arguments concerning the target's expected behaviour. These arguments are built from current and past contracts between evaluator and target. We prove that our method extends a standard computational method for trust that relies upon statistical information only. We observe experimentally that the two methods have identical predictive performance when the evaluator is highly "cautious", but our method gives a significant increase when the evaluator is not or is only moderately "cautious". Finally, we observe experimentally that target agents are more motivated to honour contracts when evaluated using our model of trust than when trust is computed on a purely statistical basis.

March 10, 2010

Speaker: Andreas Herzig (IRIT)

Title: The dynamic logic of propositional control

Abstract: Along the lines of Coalition Logic of Propositional Control (CLPC), we propose a dynamic logic of propositional control DLPC. It extends classical propositional logic by a variety of modal operators of assignment, and modal operators of transfer of control over a propositional variable. We also present an epistemic extension. We establish the relationship of these logics with the existing CLPC and with its extension by control transfer DCLPC. We study their complexity and their proof theory.

February 25, 2010

Speaker: Jan Broersen (Utrecht University)

Title: A stit-logic analysis of intentional action

Abstract: We study intentional action in stit-logic. The formal logic study of intentional action appears to be new, since most logical studies of intention concern intention as a static mental state. We model an intended action as an action that possibly deviates from the actual action conducted by an agent. First, an actual action may deviate from an intended action because the agent is not able to carry out the intended action, and the actual action is used as a means to achieve the goal of the intended action. This explains differences such as the one between the actions `murder' and `manslaughter', and problems like the `dentist's' scenario of Cohen and Levesque. Second, an actual action may deviate from an intended action because the agent's environment behaves unexpectedly and the result of an action is not the one envisaged by the agent. So, the action is unexpectedly unsuccessful. We show how to deal with the distinction between successful and non-successful action by weakening the notion of `knowingly doing' to its `belief' equivalent. Finally, we briefly consider weakening the epistemic attitude towards action performance even further by discussing opportunities to model the notion of `attempt'.

January 28, 2010

Speaker: Hans van Ditmarsch (University of Sevilla)

Title: Security protocols using card deals

Abstract: In the mid-19th century, Thomas Kirkman and Jacob Steiner gave birth to what later became known as design theory, a subdiscipline of combinatorial mathematics. Tools and techniques from that area can be used to design unconditionally secure (communicative) protocols. The epistemic logician can also focus on the epistemic properties of such protocols, or reformulate their specifications (such as security requirements) in such terms. Individual, common and distributed knowledge all play a role. Following original contributions from the 1980s onward by Winkler, Fischer, Wright and others, we focus on the case of computationally unlimited agents using card deals. Given various agents or players, two among them (sender and receiver, say, but note that they both send and receive) may wish to communicate a secret. We present some results for the restricted case where secrets concern card ownership, and for the general case where any secret bit can be exchanged by means of such card deals.

January 21, 2010

Speaker: Emiliano Lorini (IRIT)

Title: Epistemic Games in Modal Logic: from individual rationality to social preferences

Abstract: I present in this work a sound and complete modal logic called EDLA (Epistemic Dynamic Logic of Agency) integrating the concepts of joint action, preference and knowledge and enabling to reason about epistemic games in strategic form. I provide complexity results for EDLA. In the second part of the paper, I study in EDLA the epistemic and rationality conditions of some classical solution concepts like Nash equilibrium and Iterated Deletion of Strictly Dominated Strategies (IDSDS). Moreover, I combine EDLA with Dynamic Epistemic Logic (DEL) in order to model epistemic game dynamics. In the conclusion, I show how EDLA can used to model social preferences and group/team reasoning.

About the speaker: Emiliano Lorini has received a PhD in Cognitive Sciences from the University of Siena (2007). In 2007-2009, he was a post-doctoral researcher at the Institut de Recherche en Informatique de Toulouse (IRIT), France. He is actually a CNRS researcher at the university of Toulouse and at IRIT. He is working on several topics in the area of logic, multi-agent systems and cognitive sciences: theory of intentional action, theory of emotions, logical foundations of game theory, deontic logic, theory of institutions and organizations, theory of collective action and collective intentionality.

November 19, 2009

Speaker: Tony Hunter (University College London )

Title: Computational Models of Argumentation for Richer Logics

Abstract: Abstract argumentation provides a natural starting point for modelling argumentation. In abstract argumentation, a graph is used to represent a constellation of arguments and the conflict between them. Each argument is represented by a node, and the attack of one argument on another is represented by a directed arc. Proposals by Phan Minh Dung and others then give principled ways for determining which arguments are acceptable based on the structure of the graph. However, abstract argumentation assumes the existence of such graphs and does not provide means for generating them. To address this, Henry Prakken and others, have shown how logic can be used to generate arguments and to identify conflict between arguments. However, most proposals for using logic, assume a simple defeasible logic. Yet, elsewhere in artificial intelligence, there is the need to use richer logics such as classical logics, description logics, modal logics, temporal logics, and probabilistic logics. In this talk, we consider a framework for harnessing richer logics in computational models of argument.

November 5, 2009

Speaker: Alexandru Baltag (Oxford University)

Title: Iterated Belief-Revision with Higher-Level Information: from doxastic cycles to learning the truth

Abstract: I investigate and compare the long term-behavior of various belief-revision "methods" (or "belief-revision policies", or "belief upgrades", as they are sometimes called), under learning of higher-level doxastic information. By "learning" I mean iterated belief revision with new truthful information. By "higher-level doxastic information" I mean sentences that may refer to the agent's own beliefs, or to her belief-revision plans (her conditional beliefs), even if they also convey factual information. "The long-term behavior" refers to whether or not the agent's beliefs stabilize eventually, converging to a fixed point, or keep changing forever, in infinite cycles. If they do stabilize, we are interested to find natural conditions ensuring they converge to true beliefs (or even to true and complete beliefs).
The methods I consider are the following: conditioning; the "conservative upgrade" or "minimal revision" of Boutilier; a variant of minimal revision (re)formulated in terms of Spohn ordinals; lexicographic (or "radical") upgrade (initially proposed, and rejected, by Spohn, then generalized by Nayak, and justified by Glaister based on symmetry reasons, and by Baltag and Smets as a special case of the "Action-Priority Update Rule"); Spohn's ordinal analogue of Jeffrey conditioning; Darwiche and Pearl's natural modification of Spohn's method (called the "ratched method" by Kelly); Goldszmidt and Pearl's method etc.
My results are in general negative, with two exceptions: when starting with an initial finite Spohn model, the only methods that guarantee convergence of (simple) beliefs are conditioning and lexicographic upgrade (as well as its Nayak generalization). For these two types of upgrades, one can easily find natural conditions ensuring that a stream of upgrades converges to true and complete beliefs (the condition is to have a "maximally informative upgrade stream"). The positive result for lexicographic upgrades is non-trivial. I also give characterizations of the fixed points reached eventually (if reached), of the 2-cycles, 3-cycles etc.
In the end, I relate this discussion to Learning Theory, to the Surprise Examination Puzzle and (time-permitting) to the issue of belief merge via persuasive communication within a group, with applications to rationality announcements in games of perfect information.
This talk is based on joint work with Sonja Smets.

About the speaker:
1989: Masters in Mathematics, University of Bucharest.
1990-1992: Journalist.
1992-1993: Researcher at the Institute of Mathematics of the Romanian Academy.
1993-1998: Fulbright research fellowship at Indiana University.
1998: PhD in Mathematics, Indiana University, under the supervision of Jon Barwise and Larry Moss.
1998-2001: Post-doctoral Researcher, at CWI and ILLC (Amsterdam).
2001-present: University Lecturer, Oxford University Computing Laboratory.
modal logic, dynamic logic, epistemic logic, temporal logic;
belief revision, models for multi-agent information flow;
quantum logic and quantum information flow;
coalgebras, non-well-founded sets, Universal Set Theory, models for self-reference, circularity and fixed-points;
rationality and action in Game Theory;
Epistemology, Philosophy of Information and Philosophy of Science.

October 22, 2009

Speaker: Juan Antonio Rodriguez (IIIA, Spain)

Title: On the emergence of social conventions in multi-agent complex networks

Abstract: Distributed mechanisms that regulate the behavior of autonomous agents in open multi-agent systems (MAS) are of high interest since we cannot employ centralized approaches relying on global knowledge. In actual-world societies, the balance between personal and social interests is self-regulated through social conventions that emerge in a decentralized manner. As such, a computational mechanism that allows to engineer the emergence of social conventions in MAS can become a highly promising tool to endow open MAS with self-regulating capabilities. To this end we propose a computational self-adapting mechanism that facilitates agents to distributively evolve their social behavior to reach the best social conventions. Our approach borrows from the social contagion phenomenon: social conventions are akin to infectious diseases that spread themselves through members of the society. We will experimentally show that our mechanism helps a MAS to regulate itself by searching and establishing (better) social conventions on a wide range of interaction topologies and dynamic environments. Moreover, we will also show that the mechanism can cope with large convention spaces. Finally, we will turn our attention to the robust emergence of social conventions. Current computational models for the emergence of conventions assume that there is no uncertainty regarding the information exchanged between agents. However, this assumption is too strong when unreliable information might be exchanged because agents may: (i) deliberately lie; (ii) make wrong assessments or misjudgements; or (iii) communicate through noisy channels. Hence, within these settings conventions may fail to emerge. We will show how to extend our mechanism for the emergence of conventions to help agents reach global consensus on conventions despite information uncertainty. The extension is based on allowing agents to self-protect against unreliable information.

September 24, 2009

Speaker: Guillaume Aucher (ILIAS)

Title: BMS revisited

Abstract: In knowledge representation, the insight of the BMS logical framework (proposed by Baltag, Moss and Solecki) is to representhow an event is perceived by several agents very similarly to the way one represents how a static situation is perceived by them: by means of a Kripke model. There are however some differences between the definitions of an epistemic model (representing the static situation) and an event model. In this talk I will restore the symmetry. Unlike any other logical framework, this one allows to express statements about ongoing events, which are very useful in knowledge representation. It also models the fact that our perception of events (and not only of the static situation) can also be updated due to other events. I axiomatize it and prove its decidability. Finally, I show that it embeds the BMS one (if one adds common belief operators).

About the speaker: Guillaume Aucher is one of the ICR team members.

September 16, 2009

Speaker: Angela Bovo (ONERA Toulouse)

Title: Validity of a speech reported by several consecutive sources

Abstract: We are trying to determine the degree of trust we can give to a speech that has been reported by several consecutive sources, in a multi-agent, non-cooperative context. We propose a modal logic modeling for reported speech. We then define its properties of validity and invalidity, and the criteria for validity. In addition, we will show how this work relates to the Agent Communication Languages (ACLs). This work has possible applications in intelligence.

About the speaker: Angela Bovo is a master student in artificial intelligence. She studied in the University of Toulouse 3 and in the engineering school Ecole Nationale Superieure de l'Aeronautique et de l'Espace. She is currently working in the ONERA (Toulouse) for her master internship. She is currently working on language modelling, epistemic and doxastic logic as well as non cooperative agent communication languages. Angela would like to work on cognitive sciences and possibly spiking neural networks in the future.

July 30, 2009

Speaker: Alexander Artikis (Demokritos, Athens)

Title: Dynamic Protocols for Open Agent Systems

Abstract: Multi-agent systems where the members are developed by parties with competing interests, and where there is no access to a member's internal state, are often classified as 'open'. The specification of protocols for open agent systems of this sort is largely seen as a design-time activity. Moreover, there is no support for run-time specification modification.
Due to environmental, social, or other conditions, however, it is often required to revise the specification during the protocol execution. To address this requirement, we present an infrastructure for 'dynamic' protocol specifications, that is, specifications that may be modified at run-time by agents. The infrastructure consists of well-defined procedures for proposing a modification of the 'rules of the game' as well as decision-making over and enactment of proposed modifications. We evaluate proposals for rule modification by modelling dynamic specifications as metric spaces. Furthermore, we constrain the enactment of proposals that do not meet the evaluation criteria.

About the Speaker: Alexander Artikis is a research associate at the National Centre for Scientific Research "Demokritos", in Athens, Greece, and a visiting researcher at Imperial College London. He was awarded his PhD in Computing (Multi-Agent Systems) from Imperial College London in 2003. His research interests lie in the areas of temporal representation and reasoning, and distributed artificial intelligence. He has been publishing papers in related conferences and journals, such as the Artificial Intelligence Journal, and the ACM Transactions on Computational Logic.

July 28, 2009

Speaker: Piotr Kazmierczak, University of Warsaw

Title: On tableau systems for some modal logics

Abstract: This paper is an attempt to present and compare two different tableau systems for modal logic K. First we present general philosophical ideas behind theorem proving and modal logics, then we briefly describe tableau for PC, and further tableaux for modal logics. Tableau systems are indeterminate, but with some additional regulations they can be turned into decision procedures—we show how is it achieved. We also present a somewhat innovative way to construct a labelled tableau for K, and at the end we show implementations of theorem provers for PC and K written in SWI Prolog. What is yet to be presented in the paper (not yet written) is an efficienct comparison between two different tableaux for K. It will be a strictly practical comparison (like a benchmark), showing strenghts and weaknesses of these systems.

June 18, 2009

Speaker: Xavier Parent (ILIAS, ICR)

Title: Remedial interchange, contrary-to-duty obligation, and commutation

Abstract: The talk will focus on the relation between deontic logic and the study of conversational interactions. Special attention will be given to the notion of remedial interchange introduced by E. Goffman into the literature on conversational interactions. This notion appears to be close to the one of contrary-to-duty (reparational) obligation, which deontic logicians have been studying in its own right. I will investigate the question of whether some of the aspects of conversational interactions can fruitfully be described using formal tools originally developed in the study of iterated belief change. I will adapt the latter tools to deontic logic, and attempt an account of remedial interchange (and, more generally, contrary-to-duty reasoning) in terms of commutation. This account brings the dynamics of obligations to the fore.

About the speaker: Xavier Parent is a research associate in the Individual and Collective Reasoning (ICR) group at the University of Luxembourg. His current research interests are focused upon both fundamental and applied research related to deontic logic, with a special focus on dyadic deontic logic and the like. He obtained a Ph.D in philosophy with his thesis ``Non-monotonic Logics and Modes of Argumentation. The case of conditional obligation". Prior to joining the ICR group in Luxembourg, he was a research associate at the Computer Science Department of the King's College London, UK.

April 29, 2009

Speaker: Matteo Baldoni (University of Turino)

Title: Choice, Interoperability, and Conformance in Interaction Protocols and Service Choreographies (a joint work with C. Baroglio, A. K. Chopra, N. Desai, V. Patti, M. P. Singh)

Abstract: Many real-world applications of multiagent systems require independently designed (heterogeneous) and operated (autonomous) agents to interoperate. We consider agents who offer business services and collaborate in interesting business service engagements. We formalize notions of interoperability and conformance, which appropriately support agent heterogeneity and autonomy. With respect to autonomy, our approach considers the choices that each agent has, and how their choices are coordinated so that at any time one agent leads and its counterpart follows, but with initiative fluidly shifting among the participants. With respect to heterogeneity, we characterize the variations in the agents' designs, and show how an agent may conform to a specification or substitute for another agent. Our approach addresses a challenging problem with multiparty interactions that existing approaches cannot solve. Further, we introduce a set of edit operations by which to modify an agent design so as to ensure its conformance with others.

About the Speaker: Matteo Baldoni is an associate professor at the Department of Computer Science of the University of Torino since 2006 where he took his Ph.D. in Computer Science in May 1998. From July 1999 through September 2005 he has been researcher at the Department of Computer Science of the University of Torino. He has a background in computational logic, modal and non-monotonic extensions of logic programming, multimodal logics, reasoning by actions and change. His current research interests include issues in communication protocol design and implementation, conformance and interoperability for agents and web services, agent programming languages, web services and service oriented architecture, personalization by reasoning in the semantic web, e-learning.

April 2, 2009

Speaker: Hans Rott (University of Regensburg)

Title: The Ramsey Test for Conditionals and Iterated Theory Change

Abstract: According to the Ramsey Test, conditionals reflect changes of theories (or beliefs): A>B is accepted in T iff B is accepted in the minimal revision of T necessary to accommodate A. More than 20 years ago, the Ramsey test has come under heavy attack. A series of impossibility theorems ("triviality theorems") seemed to show that given standard models of theory change, the Ramsey test cannot serve as a viable analysis of conditionals. Other authors have come to its defence, arguing that it is rather the standard AGM-type model of theory change that is mistaken. In this talk I argue that an overly postulational approach to the semantics of (nested) conditionals should be avoided and that one should instead turn to an analysis in terms of constructive models of (iterated) theory change.

A crucial question is whether it is possible to use the Ramsey Test for the interpretation of conditionals and still respect the Preservation Condition according to which the original theory T should be fully retained after a revision by information that is consistent with T. Among the four most natural models for iterated belief change, I identify two solutions that indeed allow us to combine the Ramsey test with Preservation in languages containing only non-nested conditionals of the form A>B. These solutions, however, violate Preservation for nested conditionals of the form A>(B>C). I argue that by looking at the constructve models, we can understand why it has been wrong to expect that Preservation holds in languages containing nested conditionals.

March 12, 2009

Speaker: Dov Gabbay (King's College / University of Luxembourg)

Title: Matrix Abduction with Applications to Argumentation Theory and Paradoxes of Voting

Abstract We motivate and introduce a new method of abduction: Matrix Abduction. Given a matrix A with entries in {0, 1}, we allow for one or more blank squares in the matrix, say ai,j = ?. The method allows us to decide whether to declare ai,j = 0 or ai,j = 1 or ai,j = ? undecided. This algorithmic method is then applied to modelling several legal and practical reasoning situations including the Talmudic rule of Kal-Vachomer. We show that this new method can also be applied to the analysis of paradoxes in voting and judgement aggregation. In fact we have here a general method for executing non-deductive inferences. The method also offers a non deductive realisation of argumentation networks, where arguments are abduction matrices and the form of attack is matrix expansion.

About the Speaker: Dov Gabbay is one of the godfathers of the field of formal logic.

March 5, 2009

Speaker: Martin Caminada and Gabriella Pigozzi (ILIAS)

Title: On Judgement Aggregation in Abstract Argumentation

Abstract We present a paper that we have recently written for the special issue on computational social choice of the Journal of Autonomous Agents and Multi-Agent systems (JAAMAS). The topic is applying judgement aggregation to abstract argumentation

January 15, 2009

Speaker: Catherine Pelachaud (CNRS, TELECOM ParisTech)

Title: Virtual humanoid listener

Abstract Communicating with virtual humanoids imply they should have the capability to speak and to listen. In the past years we have concentrated our effort on creating a virtual humanoid able to communicate not only through speech but also through its nonverbal behaviours. It can display facial expression of emotion, it can gaze at a person, it can describe an object or show a point in space, etc. Lately we have started to work on a listener model. In a conversation not only the speaker but also the listener are active participants. Both interactants send verbal and nonverbal messages. Trough facial expression, head movement, or even gaze, the listener indicates what are its attitudes toward the speaker’s say, if it likes or dislikes, agrees or disagrees, understands or not, etc. In this talk we will present on-going work on the creation of a virtual humanoid able to communicate with human users. In particular we will describe our model of a virtual listener able to react to speaker’s speech and to indicate its mental state in real-time.

About the speaker Catherine Pelachaud is a Director of Research at CNRS in the laboratory LTCI, TELECOM ParisTech. In 1991 she obtained her PhD in Computer Graphics at the University of Pennsylvania. During 1993 and 1994 she was postdoc with a National Science Foundation grant, involved in the production of a system which automatically generates and animates conversations between multiple human-like agents with appropriate and synchronized speech, intonation, facial expressions, and hand gestures. Her current reserach topics are:

Catherine Pelachaud is member of the Ph.D. committee of Patrice Caire.

December 8, 2008

Speaker: Martin Rehak (Department of Cybernetics, Czech Technical University, Prague)

Title: CAMNEP: Collaborative Reduction of False Positives in Network Intrusion Detection

Abstract: Current network behavior analysis methods based on anomaly detection approaches suffer from comparatively higher error rate and low performance. We propose a framework system which addresses these issues by (i) using hardware-accelerated probes to collect unsampled NetFlow/IPFIX data from gigabit-speed network links and (ii) combining several anomaly detection algorithms by means of collective trust modeling, a multi-agent data fusion method. The data acquired on the network is preprocessed in the collector database and then passed to several anomaly detection methods to obtain several independent anomaly opinions for each flow. Each of these methods uses a distinct set of aggregate traffic features to determine the anomaly of each flow, which is determined by comparing the observed flows with a method-specific traffic prediction and/or a set of rules. The anomaly data is passed to several trust models to aggregate the current anomalies with past experience. Each of the trust models represents the flows in a high dimensional feature space, and progressively builds flow clusters which represent typical traffic behaviors. The clusters are labeled with the typical anomaly of the flow in the cluster, and this trustfulness (i.e. the anomaly aggregated over a long term) is used to evaluate the current flows, instead of the immediate anomaly determined for this flow. The trustfulness values provided by trust models based on different features are integrated into the final result and compared with a dynamically-defined threshold. Our experiments performed on real university and WAN networks suggest that the framework significantly improves the error rate while being computationally efficient, and is able to process the network speeds up to 1Gbps in online mode. Depending on the specific network, it can remove up to 95% of false positives when compared to individual anomaly detection methods, and up to 75% of false positives when compared to simple average of flow anomalies.

About the speaker: Martin Rehak holds engineering degree from Ecole Centrale Paris. He is currently researcher at Agent Technology Group of the Gerstner laboratory and in the same time pursues his PhD studies at the Department of Cybernetics of the Czech Technical University. His current research interests are security, network intrusion detection, trust modeling and task allocation in adversarial environments.
Prior to his current position, Martin was member of the Mobile Communication Operations team of Schlumberger Smartcards (now Axalto), where he was working on definition, design and integration of novel location-based and other value added services for major European and African operators. Before obtaining his degree, he was a freelance contractor to diverse Czech and French companies, including General Electric Medical Systems. Martin is a 2005 McKinsey Scholar, and a member of AAMAS’06-08 program committee. In 2006, he was a visiting researcher with National Institute of Informatics, Tokyo.

December 4, 2008

Speaker: Davide Grossi (ILIAS)

Title: Correspondences in the theory of aggregation

Abstract In this talk I will investigate some interrelationships between the social-theoretic problems of preference and judgment aggregation from the perspective of formal logic. On the one hand, preference aggregation will be shown to be equivalent to the aggregation of some special types of judgments (logical formulae). On the other hand, the judgment aggregation problem will be proven equivalent to the aggregation problem of specific types of preferences. As a result, a detailed map of aggregation problems is obtained which highlights differences and similarities between the two research fields of preference and judgment aggregation, which allows the cross import of impossibility results between them, and which makes a systematization of the two fields possible.

About the speaker Davide Grossi has been a member of our ICR research group in 2008 and will soon start to work at the ILLC in Amsterdam.

October 22, 2008

Speaker: Juliana Bueno-Soler (UNICAMP, Brazil)

Title: Anodic and cathodic modalities: managing negatons in modal logic

Abstract: I will discuss the role of negaton in the domain of anodic logics (modal logics withouth negation) and cathodic logics (paraconsistent modal logics with some kind of negation). Motivations for studying such logics as connected to some deontic paradoxes will be given. Some difficulties about completeness for anodic logics will be emphasized, and completeness results, as well as an incompleteness result, will be sketched. This is a work in progress, and questions, problems and research lines wil be also assessed.

About the speaker: Juliana Bueno-Soler is a visiting PhD student from the Department of Philosophy and CLE at UNICAMP, Brazil.

October 16, 2008

Speaker: Jonathan Ben-Naim (IRIT)

Title:Evaluating Trustworthiness from Past Performances: Interval-based Approaches (joint work with Henri Prade)

Abstract: In many multi-agent systems, the user has to decide whether he (or she) sufficiently trusts a certain agent to achieve a certain goal. To help users to make such decisions, an increasing number of trust systems have been developed. By trust system, we mean a system that gathers information about an agent and evaluates its trustworthiness from this information. The aim of the present paper is to develop new trust systems that overcome limitations of existing ones. This is a challenging problem that raises questions such as: how trustworthiness may be represented, and from which information it may be estimated? We assume that a set of grades describing the past performances of the agent is given. With this common basis, two approaches are proposed. In the first one, the aim is to construct an interval that summarizes the grades. Such an interval gives a good account of the trustworthiness of the agent. We establish axioms that should be satisfied by summarizing methods, devise a particular method based on pulling, and check that it satisfies the axioms, which provides theoretical justifications for it. In the second approach, which is more briefly presented, a level of trust as the certainty that a future grade will be good, and a level of distrust as the fear that a future grade may be bad, are computed on the basis of the past grades. This approach is based on possibility theory and provides, thanks to the two levels, another view of trustworthiness, as well as summarizing intervals.

About the speaker: Jonathan Ben-Naim has received a PhD in Computer Science from the University of Aix-Marseille (2006). In 2006-2007, he was a post-doctoral researcher at the University of Luxembourg. Since October 2007, he is a CNRS researcher at the university of Toulouse. He is currently working on the development and the axiomatization of trust and reputation systems.

October 9, 2008

Speaker: Walter Carnelli (State University of Campinas, Brazil)

Title: Possible-Translations Semantics and Logics of Formal Inconsistency

Abstract: Besides its great importance for mathematical reasoning, standard logic, sometimes called "classical logic", cannot be seriously accepted as a basis for rationality. Indeed, rationally acceptable statements are not coincident with true statements, and contradictions in reasoning sometimes play a most important role. So, for instance, only contradictory allegations can make a judge decide whether there is any false statement around--there is no other reason why, in justice, people are interviewed in separate. Much to the contrary to what some philosophers maintain, in informal reasoning the use of contradictions is inherent and contradictions may contain precious information. It is a task of logic to offer a suitable formal model for the perfectly licit act of reasoning under contradictions, and paraconsistent logic accomplishes this. In particular, the wide family of "ogics of formal inconsistency" (LFI's) achieve this in a remarkably natural and elegant way. The possible-translations semantics (PTS's) were devised in 1990 in order to offer a palatable interpretation to some non-classical logics, and are very well adapted to LFI's. PTS's depart from the notion of translations as morphisms between logics (maps preserving their consequence relations). If translations are thought as different "world views", the concept of possible-translations semantics offer a way to interpret a given logic L as the combination of all possible "world views", technically viewed as an appropriate set of translations of the formulas of L into a class of "simpler" logics with known semantic characterization. In this way LFI's give a very natural account of understanding the phenomenon of a sentence and its negation being both true. However, PTS's can be given to non-paraconsistent logics as well, and also serve as a powerful tool to decompose logics in the spirit of the program of combining logics. Several examples will be discussed and some research directions will be suggested.

About the speaker: Walter Carnielli is professor of the Department of Philosophy and of the Centre for Logic, Epistemology and the History of Science at the University of Campinas, Brazil. He has a Master degree in Algebra (1978) and a Ph.D. in Logic (1982) from the University of Campinas, with post-doc positions at the University of California, Berkeley and in Germany (Münster and Bonn) as Alexander von Humboldt grantee. Carnielli's research is focused on foundations of non-classical logics and applications to common-sense reasoning and computation. He is presently visiting the Individual and Collective Reasoning group at CSC- University of Luxembourg on an FNR research grant.

July 31, 2008

Speaker: Mehdi Dastani (Utrecht Univerity)

Title: Normative Multi-Agent Programs and Their Logics

Abstract: Multi-agent systems are viewed as consisting of individual agents whose behaviors are regulated by an organization artefact. This paper presents a simplified version of a programming language that is designed to implement norm-based artefacts. Such artefacts are specified in terms of norms being enforced by monitoring, regimenting and sanctioning mechanisms. The syntax and operational semantics of the programming language are introduced and discussed. A logic is presented that can be used to specify and verify properties of programs developed in this language.

About the speaker: Mehdi Dastani is a lecturer in computer science at the Utrecht University. He has received his master degrees in computer science (1991) and philosophy (1992) from the University of Amsterdam and obtained his PhD degree (1998) at the institute for logic, language and computation, University of Amsterdam. He is currently working in the area of multi-agent systems, multi-agent programming, and agent logics for the last ten years and has published many papers on these subjects.

July 31, 2008

Speaker: Odinaldo Rodrigues (King's College)

Title: A multi-level framework for information change

Abstract: In belief revision, it is often the case that preference and consistency are intertwined concepts. The most general view is that of an input formula which is preferred to an old belief set when together they are inconsistent (in the classical logic sense). This is not always adequate for several reasons and many variations of belief revision techniques have been proposed to address specific issues, e.g., iteration of the revision process.

In this talk, we argue that a relaxation and separation of some the key concepts is issential for any practical application of belief revision. We then propose a multi-level model in which different aspects of the problem can be represented and dealt with separately according to the application area's particular needs. We illustrate the technique with an example used in the modelling of requirements specification in software engineering.

About the speaker: Odinaldo Rodrigues has a BSc in Informatics from the University of Fortaleza, a MSc in Systems Engineering and Computation from the Federal University of Rio and a PhD in Computing from Imperial College London. He is currently a member of the Group of Logic, Language and Computation in King's College London. His research concentrates on the formalisation of common-sense reasoning, theory change and Artificial Intelligence techniques and their applications to computer science.

July 24, 2008

Speaker: Maria Biryukov (ILIAS, MINE)

Title: Language Classification of Personal Names with Application to DBLP

Abstract: We propose a new perspective for the data analysis in digital libraries, bibliographic and other databases containing personal names. Knowing language/cultural background of a person can be beneficial in many applications, however this information is often not present explicitly in the databases. We present in this talk a statistical tool for the automatic language detection of personal names. Our system does not require a dictionary of names for training and handles 14 different languages so far. General purpose corpora for all Western European, Chinese, Japanese and Turkish languages are used in order to build simple statistical models of the languages. The system is fine tuned to achieve precision and recall above 90% for many languages. On an example of a bibliographical database DBLP we show how our system can be used in tasks such as data cleaning and discovery of trends. In the second part of the talk we demonstrate how the co-author network, which is built from the bibliographic records, an be incorporated into the process of personal name language classification. Testing the model on the DBLP data set shows that the extension of the language classification process with the co-author network may help to refine the classification obtained from the author names considered independently. It may also lead to the discovery of dependencies between the elements of the co-author network, or participation of authors in scientific communities.

About the speaker: Maria has graduated in Master in Artificial Intelligence program from K.U. Leuven in September 2004. In 2005-2006 Maria was working in the University of Namur where she was involved in the project aiming at development and implementation of a domain independent tool for creation of question answering systems. In January 2007 Maria joined the University of Luxembourg as a Ph.D student and is working in the MINE group under the supervision of Prof. Christoph Schommer.

July 21, 2008

Speaker: Thierry Mamer

Title: Improving the use of ILP for Biological Grammar Acquisition

Abstract: This talk will present some of the recent work done in my PhD studies. In the first part of the talk, some basic principles of Inductive Logic Programming (ILP), Biological Grammar Learning and Minimum Description Length will be introduced. The second part will identify a shortcoming of a standard positive-only clause evaluation function within the context of learning biological grammars and explain how we propose to overcome it. We will describe L-modification, a modification to this evaluation function such that the lengths of individual examples in the training data are considered. We will show, among other things, that using L-modification to learn from a protein family called Neuropeptide Precursors results in induced grammars that have a better performance than that achieved when using the standard positive-only clause evaluation function.

About the speaker: Thierry is a research student at the Robert Gordon University in Aberdeen, Scotland. He has graduated with an honours degree in Computer Science (Artificial Intelligence) in 2005. He is currently conducting his last experiments and hopes to start writing up his PhD thesis soon. His current interests lie in the area of Machine Learning, Inductive Logic Programming, Bioinformatics, and loosely in Data Compression.

July 10, 2008

Speaker: Sascha Kaufmann (CSC)

Title: Making Web Portals Convivial

Abstract: In this talk, we want to motivate the idea of conviviality in web portals and argue that a convivial social being deeply depends on the implicit and explicit co-operation and co-laboration of natural users inside a community. Our belief is that an individual conviviality can benefit from the wisdom of the crowd, meaning that a continuously and dynamic understanding of the user's behaviour can heavily influences the inidividual well-being.

For this, we introduce the system CUBA, which stands for "Conviviality and User Behavior Analysis". The purpose of CUBA is to find novel ways to support users during their visits while discovering their interests. In this respect, CUBA comes up with certain recommendations and suggestions, which are partially based on a common behavior of participants in general. For example, concepts like time, space, and diverse user-based actions are taken into account. The talk closes with a report about the current state of the project.

About the speaker: Sascha Kaufmann received his diploma in Computer Science from the JW Goethe-University in Frankfurt/Main. He is now a doctoral student at the MINE Group, ILIAS Laboratory.

July 7, 2008

Speaker: Yining Wu (ILIAS)

Title: Towards an Argument Game for Stable Semantics

Abstract: We present a discussion game for argumentation under stable semantics. Our work is inspired by Vreeswijk and Prakken, who have defined a similar game for preferred semantics. We restate Vreeswijk and Prakken’s work using the approach of argument labellings and then show how it can be adjusted for stable semantics. The nature of the resulting argument game is somewhat unusual, since stable semantics does not satisfy the property of relevance.

The current presentation is a try-out for a talk at the CMNA workshop (Computational Models of Natural Argument) at the end of July.

About the speaker: Yining Wu has obtained a Master's degree of Computational Logic at the Technische Universität Dresden and is currently doing a PhD on Argumentation and Trust at the ILIAS group of the University of Luxembourg.

July 3, 2008

Speaker: Manfred Jaeger (Aalborg University)

Title: Probabilistic modeling and learning in relational domains

Abstract: In the last few years we have seen the emergence of the new field of "Statistical Relational Learning", also called "Probabilistic Logic Learning", or "Relational Data Mining". The plethora of labels results from the fact that this field is a confluence of several quite distinct strands of research: one line of research is the combination of probabilistic graphical models with more abstract, logic-based, knowledge representation languages. A second line of research contributing to the new field are probabilistic extensions of inductive logic programming techniques. Finally (and perhaps most significantly), probabilistic logic learning joins together these AI traditions with those areas in machine learning that are concerned with learning from structured data (graphs, sequences, relational databases, ...).

In this talk I will first introduce Probabilistic Logic Models as a formal semantic basis for a wide range of models and representation languages used in statistical relational learning, especially the language of Relational Bayesian Networks, which will also be described. Finally, I will present recent developments on parameter learning for Relational Bayesian Networks, and on relational feature discovery using Type Extension Trees.

About the speaker: Manfred Jaeger obtained a Diploma in Mathematics from Freiburg University in 1991, and a PhD in Computer Science from the University Saarbrücken in 1995. From 1995 to 2003 he was research associate at the Max-Planck Institute for Computer Science in Saarbrücken, and also spent time as postdoctoral researcher at Stanford University, Helsinki University, and Freiburg University. In 2003 he joined the Machine Intelligence group at Aalborg University as Associate Professor. His research centers around the integration of probabilistic and logical reasoning in Artificial Intelligence and Machine Learning.

May 26, 2008

Speaker: Jean-François Raskin (Université Libre de Bruxelles)

Title: An introduction to games played on graphs

Abstract: In this talk, I will review the fundamental notions underlying the notion of games played on a graph. I will consider both turn-based and concurrent games, different notions of strategies, winning conditions, and the foundations for algorithms to solve those games.

About the speaker: Jean-François Raskin was born in Belgium, in 1972. He received his master and Ph.D. degrees in computer science from the Université de Namur, Belgium, in june 1995 and april 1999, respectively. After long research stays at the University of California at Berkeley, Max-Planck Institute for Computer Science (Saarbrucken), and ENS Paris, he is now Associate Professor (chargé de cours) at the computer science department of the Université Libre de Bruxelles (ULB), Belgium. His research interests are the formal methods for the verification of concurrent, real-time, and hybrid systems. At the ULB, he teaches subjects in theoretical computer science : automatic proofs and proofs of programs, logic in computer science, computability and complexity, and analysis of hybrid systems. He is also the secretary of the Belgian F.N.R.S. contact group on Theoretical Computer Science.

May 22, 2008

Speaker: Henry Prakken (University of Utrecht / University of Groningen, the Netherlands)

Title: Integrating Different Modes of Reasoning

Abstract: Many reasoning problems involve subproblems of different kinds, which can be solved in different ways. In this talk an abstract formalism will be presented in which any set of specific problem solving methods satisfying some weak conditions can be combined. The formalism makes it possible to formally express dependencies between different subproblems, to define an overall solution on the basis of solutions to subproblems, and, most importantly, to manage alternative, incompatible solutions to (sub)problems. The formalism will be illustrated with a legal example that combines standard first-order logic, Bayesian probability theory and two versions of default logic.

About the speaker: Henry Prakken is a lecturer in the Intelligent Systems group of the computer science department at Utrecht University, and professor of Law and ICT at the law faculty of the University of Groningen. He has master degrees in law (1985) and philosophy (1988) from the University of Groningen. In 1993 he obtained his PhD degree at the Free University Amsterdam with a thesis titled Logical Tools for Modelling Legal Argument. Prakken's research concerns logical foundations of common-sense reasoning and argumentation, and the application of Artificial Intelligence and advanced IT to legal reasoning, dispute resolution, group decision making and negotiation.

April 10, 2008

Speaker: Martin Mozina (University of Ljubljana, Slovenia)

Title: Integration of Machine Learning and Argumentation

Abstract: Machine learning is concerned with development of algorithms for extracting implicit knowledge from data. As these algorithms need to select among several alternative explanations of data, the resulting models often seem incomprehensible to domain experts. On the other hand, since argumentation studies and formalises common-sense reasoning and can be therefore used to represent experts' knowledge in a natural way, we can expect that their integration would yield benefits in both areas. During my talk I will introduce basics of machine learning and point out several possible combinations of machine learning and argumentation. The focus will be on recently developed approach Argument Based Machine Learning (ABML), which uses arguments provided by experts to guide machine learning algorithms towards comprehensible explanations of data.

About the speaker: Martin Mozina has received a BSc degree in computer science at the Faculty of computer and information science in Ljubljana in year 2003, and is since a PhD student at the Artificial Intelligence Laboratory. In years 2004-2007 he worked as a reasearcher on european project ASPIC (Argumentation Service Platform with Integrated Components) and currently he works now on X-Media project (Large scale knowledge sharing and reuse across media). His research mainly includes machine learning, the use of argumentation in machine learning algorithms, visualization of learned models, and programs for automatic tutoring.

March 20, 2008

Speaker: Nikos Vlassis (Dept. of Production Engineering and Management Technical University of Crete, Greece)

Title: Distributed Decision Making for Large Teams of Agents

Abstract: We address the problem of optimal action selection and coordination of a large team of collaborative agents. We view the problem as a combinatorial optimization problem where we need to maximize a payoff function that is additively decomposed over a graph. We first review a dynamic programming approach that finds the optimal solution but has exponential worst-case time complexity. We then describe an approximate message-passing algorithm for action selection, similar to belief propagation for Bayesian networks, that exhibits a very good runtime/performance trade-off. We discuss extensions to distributed stochastic optimal control, and outline possible applications.

About the speaker: Nikos Vlassis received a diploma in Electrical and Computer Engineering in 1993, and a PhD in 1998, both from the National Technical University of Athens, Greece. In 1999 he was visiting researcher at the Electro-Technical Laboratory in Tsukuba, Japan. From 2000 until 2006 he held an Assistant Professor position at the University of Amsterdam, The Netherlands. Since 2007 he holds an Assistant Professor position at the Technical University of Crete, Greece. He has published one monograph on multiagent systems and several papers in the fields of robotics and machine learning. His current research interests include robotics, multiagent systems, machine learning, and stochastic optimal control.

January 24, 2008

Speaker: Andreas Herzig

Title: Grounding power on actions and mental attitudes

Abstract: The main objective of this work is to develop a logical framework called IAL (Intentional Agency Logic) in which we can reason about mental states of agents, action occurrences, agentive and group powers. IAL will be exploited for a formal analysis of different forms of power such as an agent's power of achieving a certain result, an agent's power to do a certain action and an agent's power over another agent.

December 19, 2007

Speaker: Régis Riveret

Title: Argumentation: Game Theory as Heuristics.

Abstract: Over the years many dialogue games for argumentation have been proposed to shed light on questions such as which conclusions are (defeasibly) justified, or how procedures for debate and conflict resolution should be structured to arrive at a fair and just outcome. An aspect of debates which has not yet received much attention is the common sense observation that the outcome does not solely depend on the premises of a case, but also on the strategies that parties in a dispute actually adopt. The focus is on adjudication debates in which two participants aim to persuade each other to adopt a certain opinion and, a neutral third party (for example, a judge) must decide at the end whether to accept the statements that the opposing parties have made during the debate. In this presentation, the problem studied is how to use game theory to determine optimal strategies in dialogue games for argumentation. To do so, the main notions of Prakken's abstract argument games are interpreted in game theory, and optimal strategies are defined accordingly. Then, a specification of the expected utility of a strategy is provided by combining the probability of success of arguments with their associated costs and benefits. The presentation will also discusses some related work and, suggest future investigations.

December 13, 2007

Speaker: Carlos Ribeiro.

Title: Research on Multi-agent Systems and Complex Social Networks at the Technological Institute of Aeronautics.

Abstract: In this talk I will first present some aspects of the Technological Institute of Aeronautics (ITA) in the broad context of the Air Industry. ITA is the main centre for research and education on Aerospace, Aeronautics and Air Force issues in Brazil. Founded in 1950, it is one of the main responsibles for the important role the brazilian aeronautics industry has today, with its main company—Embraer—having produced more than 4,100 aircrafts which operate in 69 countries.
The talk will then switch to the research carried out at the Artificial Intelligence and Robotics Group at ITA, particularly in the topics on Multi-Agent Systems and Complex Social Networks. On Multi-Agent Systems, I will present our research on the design of overlay networks for incident (failures and attacks) detection in a network model. The purpose of this research is to devise mechanisms for topology control that considers na autonomous negotiation process based on a consensus among nodes in a hierarchical structure. Still in the context of Multi-Agent Systems, we present a method for pairwise combination of partial robotic maps based on paraconsistent logics which can be adapted for a consensus-based mobile robotic network. Finally, we explore the issue of Social Network Analysis regarding both its technological and theoretical aspects: a project on fraud and irregularity detection for the Brazilian Inland Revenue and the Brazilian Air Force) and the analysis of metrics for evaluating small-world properties in large social networks.

December 7, 2007

Speaker: Mozhgan Tavakolifard

Title: A Distributed and Statistical based Trust and Reputation Management Framework

Abstract: The rapidly changing environments of the internet suffer from problems such a fragile trustworthiness of millions active entities on the internet, e.g. human and mobile agent. This problem is nontrivial as more and more commercial transactions get carried out over the internet. Therefore, devising an effective way for verifying the trustworthiness entity in such complex environments is essential. To this end, Ntropi framework was designed to facilitate the exchange of trust and reputation in information/business environments. The trust mechanism plays a key role in security of multi-agent systems. Also the trust establishment is nontrivial, since the traditional and social means of trust cannot be applied directly to virtual settings of these environments. Because, in many cases the involved parties have not interacted before. Therefore, the reputation techniques must be used to estimate the good qualities and behaviors in online markets and communities, and also sanction the poor qualities and bad behaviors of this. The Ntropi has classified the trust into direct (explicit) and recommended classes. The direct class is divided into five agent-based sections called "very trustworthy", "trustworthy", "moderate", "untrustworthy", and "very untrustworthy". But the recommended trustworthy is derived from word-of-mouth (e.g., opinions), which is called reputation, and can be translated to direct or regular trusts. This paper presents an automated and autonomous trust system using Bayesian inference and improved Dirichlet distribution. Also a re-trusting mechanism (forgiveness) is devised and incorporated into Ntropi framework. This simulation results indicate the effectiveness of our model and the percentage of improvements.

November 22, 2007

Speaker: Denis Zampunieris

Location: Room E012

Title: e-Learning and Proactive Computing

Abstract: Learning Management Systems (LMS) or e-learning platforms are dedicated software tools intended to offer a virtual educational and/or training environment online. Although there are already a large number of functions for a variety of different users acting specific roles in these environments, current LMS are fundamentally limited tools. Indeed, they are only reactive software developed like classical, user-action oriented software. These tools wait for an instruction, most probably given through a graphical user interface, and then react to the user request.
Students using these online systems could imagine and hope for more help and assistance tools, especially because those users are often inexperienced ones and expect some guidelines (what to do and how to do it) from the system instead of a static user interface. LMS should tend to offer to these students some personal, immediate and appropriate support based on an intelligent analysis of their (lack of) actions, like teachers do in classrooms.
Moreover, certain users like e-tutors have to peruse lots of data in order to try to efficiently manage other users' needs and expect some clues (where to search and what to look for) from the system instead of a passive database.
We introduce a new kind of Learning Management Systems: Proactive LMS, designed to improve their users' online interactions by providing programmable, automatic and continuous analyses of users (inter-) actions augmented with appropriate actions initiated by the LMS itself.
Proactive systems [D. Tennenhouse, "Proactive Computing", Communications of the ACM, 43 (5), 2000, pp. 43–50] adhere to two premises: working on behalf of, or pro, the user, and acting on their own initiative, without user's explicit command. Proactive behaviors are intended to cause changes, rather than just to react to changes. This is a major change from interactive computing, in which we lock a system into operating at exactly the same frequency as humans do.
Our proactive LMS can, for example, automatically and continuously help and take care of e-users with respect to previously defined procedures rules, and even flag other users, like an e-tutor, if something "wrong" is detected in their behaviors; it can also automatically verify that awaited behaviors of e-users have been carried out, and it can react if these actions did not happen.

November 8, 2007

Speaker: Eugen Staab

Location: Room A02

Title: Excusableness for Failing Agents or False Negatives in Trust Assessment

Abstract: To estimate how much an agent can be trusted, its trustworthiness needs to be assessed. Usually, poor performance of an agent leads to a decrease of trust in that agent. This is not always reasonable. If the environment interferes with the performance, the agent is possibly not to blame for the failure. We examine which failures can be called excusable and hence must not be seen as bad performances. Knowledge about these failures makes assessments of trustworthiness more accurate. In order to approach a formal definition of excusableness, we introduce a generic formalism for describing environments of Multi-Agent Systems. This formalism provides a basis for the definition of environmental interference. We identify the remaining criteria for excusableness and give a formal definition for it. Our analysis reveals that environmental interference and a strong commitment of the performing agent do not suffice to make a failure excusable.

October 18, 2007

Speaker: Paul Harrenstein

Location: Room A02

Title: Dominance in Social Choice and Coalitional Game Theory

Abstract: We consider dominance relations for social choice as based on the pairwise majority rule on the one hand and cooperative games with non-transferable utility (coalitional NTU games) on the other. As these dominance relations may fail to be transitive and even contain cycles, the notion of maximality becomes untenable as an analytical tool. Both in social choice theory and cooperative game theory, a number of concepts have been proposed to take over the role of maximality in the absence of transitivity. In 1953 McGarvey showed that any irreflexive and anti-symmetric relation can be obtained by the majority rule. In this paper, we address the analogous issue for finite NTU games. We find any irreflexive relation over a finite set can be obtained as the dominance relation of some ordinary, monotonic, and simple NTU coalitional game. We also show that any dominance relation can be induced by a non-cooperative game via beta-effectivity. Furthermore, we obtain a partial result for the case in which alpha-effectivity is used and consider the formal interrelationships between Smith sets, Schwartz sets, stable sets and the core in finite NTU games.

October 11, 2007

Speaker: Girma Berhe

Title: Autonomic management for distributed systems: Example of DIET

Abstract: Today's increasingly complex architectures and distributed computing infrastructures require highly skilled IT professionals to install, configure, operate, tune and maintain them. This impedes effective and efficient execution of business processes and the delivery of services that relay on the IT infrastructure. In particular, IT management has become too complex and costly. Moreover, the fact that management tasks are performed by humans leads to many configuration errors and low reactivity. Autonomic computing helps to address these problems by providing self-managing capabilities to IT systems. In this presentation, the foucs is on the use of JADE, a middleware for self-management of distributed software environments.
The main principle is to wrap legacy systems(or software elements) in components in order to provide a uniform management interface, thus allowing the deployment of distributed applications and reconfigure them autonomously as required. A particular use case and experiments in using JADE will be presented.

October 4, 2007

Speaker: Sanjay Modgil

Title: Reasoning about Preferences in Argumentation Frameworks

Abstract: A Dung argumentation framework consists of a set of arguments related by a conflict based binary attack relation. A 'calculus of opposition' is then applied to determine the justified or 'winning' arguments under different extensional semantics. The framework abstracts from the underlying logic in which the arguments and attack relation are defined. Dung's seminal theory of argumentation has thus become established as a general framework for non-monotonic reasoning, and, more generally, reasoning in the presence of conflict.
To determine a unique set of justified arguments invariably requires that a preference relation on arguments is available. However, preference information is often itself defeasible, conflicting and so subject to argumentation based reasoning. In this talk I will describe my work on extending Dung's framework to include arguments that claim preferences between other arguments. Specifically, the framework is extended to include a second attack relation such that an argument that claims a preference between two other arguments, attacks the binary attack between these two conflicting arguments. I will describe how the the justified arguments of an extended framework are evaluated under the full range of Dung's extensional semantics, and discuss how the core results for Dung frameworks scale up to extended frameworks. I will therefore propose that the extended semantics provides a general a framework for non-monotonic reasoning formalisms that accommodate defeasible reasoning about as well as with preference information. To substantiate this proposal I will show how existing reasoning formalisms can be formalised and extended in the framework, and will illustrate with examples demonstrating agent reasoning over beliefs goals and actions.

September 13, 2007

Speaker: Kittichai Lavangnanda

Location: Room C02

Title: Introduction to Evolutionary Computation and an application in knowledge discovery (a data mining program SARG)

Abstract: Evolutionary Computation is one of the most popular techniques used in a sub-field of Artificial Intelligence (AI) known as Soft Computing or Computational Intelligence. Evolutionary Computation are used to offer solutions to problems where no known conventional methods or algorithms can guarantee optimal/best solution. Knowledge Discovery (or Data Mining) is a broad term which is used to describe techniques in discovering useful patterns hidden in a given dataset. One such techniques is to generate rules which discover these patterns by relating or associating one set of attributes to another hidden in the dataset. These set of rules are commonly known as Association Rules. The problem of generating efficient association rules can seen as search problem since many different sets of rules are possible from a given set of instances. As the application of evolutionary computation in searching is well studied, it is possible to utilize evolutionary computation in mining for efficient association rules.
In this presentation, Evolutionary Computation and its applications will be introduced in order to realize its potential. A program known as Self-adjusting Association Rules Generator (SARG) is described. SARG is a data mining program which can generate association rules for classification. It is an improvement of the data mining program called Genetic Programming for Inductive learning (GPIL). It has been tested on several benchmark data sets available in the public domain. Comparison between GPIL and SARG revealed that SARG achieved better performance and was able to classify these datasets with higher accuracy. The presentation will also discusses relevant aspects of SARG and suggest directions for future work.

September 6, 2007

Speaker: Maria Fasli

Location: Room B02

Title: Accounting for Social Order in Multi-agent Systems

Abstract: As agents are required to inhabit and operate in increasingly complex environments and interact with other agents as elements of larger systems, some means of regulating their behaviour to avoid disruption and to ensure smooth performance, fairness and stability is needed. To this end, theoretical research and in particular agent theories need to address issues such as stable group activity, regulation of behaviour and elements that contribute to social order in multi-agent systems. In this talk we will describe a formal framework that accounts for social order within a multi-agent system based on organizational and normative concepts. The fundamental building blocks of multi-agent systems are social agents whose structure can be formally characterized in terms of roles and relationships between them including authority relations. Social agents are bound together via commitments and different types of social agents may be bound by commitments in different ways. Agents are autonomous and may decide to deviate from prescribed behaviour and violate their commitments and obligations, but as a consequence they may have to face the sanctions as a result of the other agents exercising their rights.

August 23, 2007

Speaker: Richard Booth (Joint work with T. Meyer)

Location: Room B02

Title: On the dynamics of total preorders—Revising abstract interval orders

Abstract: Total preorders (tpos) are often used in belief revision to encode an agent's strategy for revising its belief set in response to new information. Thus the problem of tpo-revision is of critical importance to the problem of iterated belief revision. In a previouswork (with T. Meyer and K-S. Wong) we provided a useful framework for revising tpos which adds extra structure to guide the revision of the initial tpo. However, one shortcoming of this framework is that ith andles *single-step* tpo-revision only. In this talk I will briefly review this framework, before giving a way to extend it to consider *double-step* tpo-revision. This extension employs a new way to represent the structure required to revise a tpo, based on *abstract interval orders*.

July 13, 2007

Speaker: Mario Paolucci

Title: Repage—Reputation and Image for Partner Selection in Simple Markets

Abstract: Reputation is a fundamental instrument of partner selection. Developed within the domain of electronic auctions, reputation technology isbeing been imported into other applications, from social networks to institutional evaluation. Its impact on trust enforcement isuncontroversial and its management is of primary concern for entrepreneurs and other economic operators.
In this talk, I will introduce Repage, a computational system that adopts a cognitive theory of reputation, based on theoretical research performed at LABSS in the course of several years. One of the main proposals is a fundamental difference between image (agents' believed evaluation of a target) and reputation (circulating evaluation, without reference to the evaluation source), which suggests a way out from the paradox of sociality, i.e. the trade-off between agents' autonomy and their need to adapt to social environment. On one hand, agents are autonomous if they select partners based on their social evaluations (images). On the other, they need to update evaluations by taking into account others'. Hence, social evaluations must circulate and be represented as "reported evaluations" (reputation), before and in order for agents to decide whether to accept them or not.
To represent this level of cognitive detail in artificial agents' design, there is a need for a specialised subsystem, which we have developed for the public domain.
After presenting the system, I will shortly report upon simulation-based studies on the role of reputation as a more tolerant form of social capital than familiarity networks. Whereas the latter exclude non-trustworthy partners, reputation is a more inclusive mechanism upon which larger and more dynamic networks are constructed.In the simulation, we model the spreading of information in a simple market with the presence of liars and the possibility of retaliation. While fear of retaliation inhibits the spreading of image, the detached character of reputation can be a cause of inaccuracy; The two forces could balance indifferent settings.
Final remarks and ideas for future works will conclude the paper, with special attention on the choice of developing the system algorithmically and not within a formal logic. I will also shorty present the current lines of development in the "eRep—Social Knowledge for e-Governance" project.

July 12, 2007

Speaker: Marcello D'Agostino (joint work with Corrado Sinigaglia)

Title: Forecasting Accuracy and Subjective Probability

Abstract: De Finetti's favourite justification of the probability laws, within his "subjectivist" account of probability theory, was in terms of "scoring rules". These are rules that are often employed in evaluating the accuracy of probabilistic forecasters and measuring their predictive success. De Finetti showed that if a specific scoring rule is adopted, the so-called Brier's rule, consisting in taking the mean squared error over a time series of predictions, then the score of a forecaster whose predictions are in accordance with the probabilistic laws dominates that of any forecaster whose predictions violate them. If this has to be read as a subjectivist justification of the probability rules, a natural question to ask is: why Brier's rule? Why couldn't we measure forecasting accuracy by means of any other reasonable rule, such as the one based on the mean absolute error? Several attempts have been made in the literature to characterize Brier's rule as the only proper scoring rule satisfying some general, more or less compelling, properties. In this talk we take a different approach. We embed the scoring problem into the general problem of measuring the distance between two times series of predictions and present a set of natural properties that a distance function between such time series should satisfy. We then show that these properties uniquely determine a metric which, coincides with Brier's scoring rule in the special case in which one of the two series is generated by an "infallible" forecaster. We then argue that, in this way, De Finetti's subjectivist approach to the justification of the probabilistic laws can be accomplished without appealing to the, somewhat misleading and inconclusive, arguments based on the elicitation problem and on the notion of "proper scoring rule" which have so far been the main, if not exclusive, concern of the literature.

June 28, 2007

Speaker: Wojtek Jamroga

Title: A Logic for Reasoning about Rational Agents (joint work with Nils Bulling)

Abstract: Game theory identifies a number of solution concepts (e.g., Nash equilibrium, undominated strategies, Pareto optimality) that can be used to define rationality of players. Then, the notion of rationality can be employed to discard "less sensible" behavior of players, and determine what should happen had the game been played by ideal agents. Game-theoretical solution concepts have been also characterized invarious modal logics, including dynamic logic, dynamic epistemic logic, and alternating-time temporal logic (ATL). On the other hand, modal logics of time, action and strategies are a natural choice when one wants to reason about behavior of arbitrary agents. In this work, we try to bridge these two concepts, and propose a logic for reasoning about the behavior of agents under rationality assumptions. In particular, we do not want to commit to any particular notion of rationality; instead, we prefer to allow for "plugging in" rationality assumptions in a flexible way.

June 14, 2007

Speaker: Stijn Vanderlooy

Title: The ROC Isometrics approach.

Abstract: A wide variety of state-of-the-art machine-learning classifiers areavailable to be used in practice. Nevertheless, only few classifiers areemployed in application domains with high misclassification costs, e.g.,medical diagnosis and law enforcement.
In this talk I will outline the ROC isometrics approach. The approachprovides a framework to extend classifiers such that their performancecan be set by the user prior to classification. Hence, classifiersbecome reliable. I will show that the ROC isometrics approach ispractically useful and does not have strong assumptions. An extensiveempirical evaluation of the approach will verify the analysis.
From the analysis and experimental evaluation we may conclude that theROC isometrics approach results in classifiers that can safely beapplied in any domain.

May 3, 2007

Speaker: Jerome Lang.

Title: Sequential voting rules and multiple elections paradoxes (joint work with Lirong Xia and Mingsheng Ying).

Abstract: Multiple election paradoxes arise when voting separately on eachissue from a set of related issues results in an obviouslyundesirable outcome. Several authors have argued that a sufficient condition for avoiding multiple election paradoxes is the assumption that voters have separable preferences. We show that this extremely demanding restriction can be relaxed into the much more reasonable one: there exists a linear order x1 > ... > xp on the set of issues such that for each voter, every issue xi is preferentially independent of xi+1, ..., xp given x1, ..., xi-1. This leads us to define a family of sequential voting rules, defined as the sequential composition of local voting rules. These rules relate to the setting of conditional preference networks (CP-nets) recently developed in the Artificial Intelligence literature. We study in detail how these sequential rules inherit, or do not inherit, the properties of their local components. We focus on the case of multiple referenda, corresponding to multiple elections with binary issues.

March 22, 2007

Speakers: Foued Melakessou and Zdzislaw Suchanecki.

Title: On The Road Towards The Comprehension Of The Internet Traffic Behavior: Simulation And Analysis Of An End-To-End Connection With NS-2.

Abstract: This contribution is attempting to address the problem of understanding how different aspects of networks—physical topology and routes on that topology—along with packet arrival models lead to congestion and other observed network characteristics as its fractal and periodic behavior. We reveal topology and routing effects on data transmissions between two routers linked by a connection path in a well-defined network environment. Our statistical approach is based on log-normal distributions. We show that the fractal behavior of a network node traffic can be viewed as a consequence of the topology and routingeffects. This work is based on random simulations performed by the network simulator ns-2. We have shown that the longer the connection path, the more log-normal is the inter-arrival time distribution at the destination node. Moreover a spectrum analysis has been performed in order to emphasize the traffic periodic behavior rising from the most used transfer protocol TCP/Reno.

March 6, 2007

Speaker: Glenn Lawyer.

Title: Subtypes of controls and schizophrenia patients based on brain cortical thickness.

Abstract: Given the broad range of symptoms and known brain morphological disturbances in patients with schizophrenia, it is a priori possible that subtypes of the disease could be identified in localized cortical thickness measures. Recent advances in magnetic resonance imaging allow invivo measurement of cortical thickness at each vertex in a 1mm grid covering the entire cortex. Measurements were made on 106 patients and 96 controls. At each vertex, the number of clusters of individuals best explaining the data was determined. This was done for the patient group,the control group, and the two groups combined. It was found that the patients were primarily homogeneous with regard to cortical thickness. Exceptions were found in regions where the controls were also heterogeneous. This implies that these regions of heterogeneity are common to humanity. When the method was applied to the combined data, it largely agreed with findings of group difference previously established by significance testing.

February 22, 2007

Speaker: Marcin Seredynski.

Title: Evolution of a Strategy Driven Behavior in Ad Hoc Networks.

Abstract: We propose a strategy driven approach which aims at enforcing cooperation between network participants. Each node is using a strategy that defines conditions under which packets are being forwarded. Such strategy is based on the notion of trust and activity of the source node of the packet. These way network participants are enforced to forward packets and to reduce the amount of time of being in a sleep mode. To evaluate strategies we use a new game theory based model of an ad hoc network. This model also includes a simple reputation collection and trust evaluation mechanisms. A geneticalgorithm (GA) is applied to find good strategies.

February 8, 2007

Speaker: Bram Roth.

Title: How to preserve deterrence whilst abstaining from strategies?

Abstract: Deterrence is a relation that holds between strategies of players involvedin a game. Informally one strategy is deterrent vis-a-vis another if it canreasonably be played and there are reasonable alternatives to the deterredstrategy. More formally the reasonableness of strategies is captured by a notioncalled playability. Three systematic procedures are discussed for solving gamesof deterrence by abstaining from strategies, in order to find the playability ofeach strategy. The conditions are explored under which these procedures arevalid and their intuitive interpretations are provided. Abstaining from what iscalled a harmless strategy, for instance, is shown to be valid only if theharmless strategy does not happen to be the only safe strategy available to aplayer. An efficient algorithm for solving games is proposed on the basis of theiterative application of the procedures, and ways are suggested to explore themultiplicity of playability solutions to games of deterrence.