Magdalena Kacprzak

Verification of Multiagent Systems via Unbounded Model Checking

We present an approach to the problem of verification of epistemic properties of multi-agent systems by means of symbolic model checking. In particular, it is shown how to extend the technique of unbounded model checking from a purely temporal setting to a temporal-epistemic one. In order to achieve this, we base our discussion on interpreted systems semantics, a popular semantics used in multi-agent systems literature.We give details of the technique and show how it can be applied to the well-known train, gate and controller problem.

Unbounded Model Checking for Alternating-Time Temporal Logic

This paper deals with the problem of verification of game-like structures by means of symbolic model checking. Alternating-time Temporal Logic (ATL) is used for expressing properties of multi-agent systems represented by concurrent game structures. Unbounded model checking (a SAT based technique) is applied for the first time for verification of ATL. An example is given to show an application of the technique.

On lattice structure and implications on ordered fuzzy numbers

Ordered fuzzy numbers (OFN) invented by the second author and his two coworkers in 2002 make possible to utilize the fuzzy arithmetic and to construct the Abelian group of fuzzy numbers and then an ordered ring. The definition of OFN uses the extension of the parametric representation of convex fuzzy numbers. Fuzzy implication is proposed with the help of algebraic operations and a lattice structure defined on OFN.

Proving Propositional Tautologies in a Natural Dialogue

The paper proposes a dialogue system LND which brings together and unifies two traditions in studying dialogue as a game: the dialogical logic introduced by Lorenzen; and persuasion dialogue games as specified by Prakken. The first approach allows the representation of formal dialogues in which the validity of argument is the topic discussed. The second tradition has focused on natural dialogues examining, e.g., informal fallacies typical in real-life communication. Our goal is to unite these two approaches in order to allow communicating agents to benefit from the advantages of both, i.e., to equip them with the ability not only to persuade each other about facts, but also to prove that a formula used in an argument is a classical propositional tautology. To this end, we propose a new description of the dialogical logic which meets the requirements of Prakkens generic specification for natural dialogues, and we introduce rules allowing to embed a formal dialogue in a natural one. We also show the correspondence result between the original and the new version of the dialogical logic, i.e., we show that a winning strategy for a proponent in the original version of the dialogical logic means a winning strategy for a proponent in the new version, and conversely.

Perseus. Software for Analyzing Persuasion Process

The aim of the paper is to present the software tool Perseus and show how it can be used to examine multi-agent systems where the ability to persuade is specified. Especially we want to study the issues such as: what arguments individuals use to successfully convince others, what type of a persuader guarantees a victory etc. This work describes implementation of the tool and discusses what questions about persuasion process Perseus can answer and how it is done.

Fully Symbolic Unbounded Model Checking for Alternating-time Temporal Logic1

Alternating-time Temporal Logic (ATL) is typically applied for specifying properties of multi-agent systems modelled by game-like structures. This paper deals with verification of ATL by means of a fully symbolic model checking. Unbounded model checking (a SAT-based technique) is applied for the first time to verification of AT. Several examples are given in order to present an application of the technique.

New Approach to Decision Making

The aim of this work is to propose a new methodology for representation and processing of imprecise ideas like good hotel, good food, etc. As an example we consider the problem of verification of a hotel’s features, to choose the best place for a conference. In this approach, a vague term of a good hotel for a conference is modeled in paradigm of metasets, which involves splitting it into a tree-like hierarchy of related sub-concepts. Then, the techniques of Opinion Mining are used to determine the polarity and the intensity of opinions available on the Internet, that concern specific hotels. Finally, the membership grades for the sample hotels are calculated. These grades reflect each hotel’s total capabilities and represent the degree to which the vague idea is satisfied by each. The result is a new system that helps in decision making.

Strategies in Dialogues: A Game-Theoretic Approach

The aim of the paper is to propose a game-theoretic description of strate- gies available to players in dialogues. We show how existing dialogical systems can be formalized as Nash-style games, and how the game-theoretic concept of so- lutions (dominant strategies, Nash equilibrium) can be used to analyse these sys- tems. Our first study, discussed in this article, describes the game DC introduced by Mackenzie.

Metasets and Opinion Mining in New Decision Support System

The paper is devoted to the problem of modeling human attitudes towards imprecise ideas. A metaset is used for representing an imprecise concept and Opinion Mining techniques are applied to build a preference function which reflects someones attitude towards the idea. The preferences are then evaluated as real numbers for the sake of comparison and selection of the best matching instance. The core of the idea of repre- senting any imprecise concept with a metaset lies in splitting it into a tree- like hierarchy of related sub-concepts. The nodes of the tree determine the membership degrees for metaset members and they are natural language terms which also describe reasons for some particular member to satisfy the represented idea. The Opinion Mining allows for automatic gathering and evaluation of opinions from the Internet. The proposed mechanism is applied to solve the problem of selecting the car best matching the impre- cise idea of a good car for a lady. This approach can be applied in a decision support systems that helps both marketers and customers.

Verifying multi-agent systems via unbounded model checking

We present an approach to the problem of verification of epistemic properties in multi-agent systems by means of symbolic model checking. In particular, it is shown how to extend the technique of unbounded model checking from a purely temporal setting to a temporal-epistemic one. In order to achieve this, we base our discussion on interpreted systems semantics, a popular semantics used in multi-agent systems literature. We give details of the technique and show how it can be applied to the well known train, gate and controller problem.