Alessio Lomuscio

Automated Negotiation: Prospects, Methods and Challenges

An increasing number of computer systems are being viewed in terms of autonomous agents. There are two main drivers to this trend. Firstly, agents are being advocated as a next generation model for engineering complex, distributed systems (Jennings 2000; Wooldridge 1997). Secondly, agents are being used as an overarching framework for bringing together the component AI subdisciplines that are necessary to design and build intelligent entities (Nilsson 1998; Russel and Norvig 1995). While there is still much debate about the precise nature of agenthood, an increasing number of researchers find the following characterisation useful (Wooldridge 1997):

MCMAS: A Model Checker for the Verification of Multi-Agent Systems

While temporal logic in its various forms has proven essential to reason about reactive systems, agent-based scenarios are typically specified by considering high-level agents attitudes. In particular, specification languages based on epistemic logic [7], or logics for knowledge, have proven useful in a variety of areas including robotics, security protocols, web-services, etc. For example, security specifications involving anonymity [4] are known to be naturally expressible in epistemic formalisms as they explicitly state the lack of different kinds of knowledge of the principals.

A Classification Scheme for Negotiation in Electronic Commerce

In the last few years we have witnessed a surge of business-to-consumer and business-to-business commerce operated on the Internet. However, most current electronic commerce systems are little more than electronic catalogues that allow a user to purchase a product under predetermined and inflexible terms and conditions. We believe that in the next few years we will see a new generation of electronic commerce systems emerge, based on automated negotiation. In this paper, we identify the main parameters on which any automated negotiation depends. To show the applicability of our classification framework, we use it to categorise a representative sample of some of the most prominent negotiation models that exist in the literature.

Deontic interpreted systems

We investigate an extension of the formalism of interpreted systems by Halpern and colleagues to model the correct behaviour of agents. The semantical model allows for the representation and reasoning about states of correct and incorrect functioning behaviour of the agents, and of the system as a whole. We axiomatise this semantic class by mapping it into a suitable class of Kripke models. The resulting logic, KD45ni-j, is a stronger version of KD, the system often referred to as Standard Deontic Logic. We extend this formal framework to include the standard epistemic notions defined on interpreted systems, and introduce a new doubly-indexed operator representing the knowledge that an agent would have if it operates under the assumption that a group of agents is functioning correctly. We discuss these issues both theoretically and in terms of applications, and present further directions of work.

MCMAS: a model checker for multi-agent systems

This paper presents mcmas, a model checker for Multi-Agent Systems (MAS). Differently from traditional model checkers, mcmas permits the automatic verification of specifications that use epistemic, correctness, and cooperation modalities, in addition to the standard temporal modalities. These additional modalities are used to capture properties of various scenarios (including communication and security protocols, games, etc.) that may be difficult or unnatural to express with temporal operators only; a small number of applications are presented in Section[4]. Agents are described in mcmas by means of the dedicated programming language ISPL (Interpreted Systems Programming Language). The approach is symbolic and uses ordered binary decision diagrams (obdds), thereby extending standard techniques for temporal logic to other modalities distinctive of agents. mcmas and all the examples presented in this paper are available for download [14] under the terms of the GPL license.

Automatic verification of multi-agent systems by model checking via ordered binary decision diagrams

We present a methodology for the verification of multi-agent systems, whose properties are specified by means of a modal logic that includes a temporal, an epistemic, and a modal operator to reason about correct behaviour of agents. The verification technique relies on model checking via ordered binary decision diagrams. We present an implementation and report on experimental results for two scenarios: the bit transmission problem with faults and the protocol of the dining cryptographers.

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.

Model Checking and Artificial Intelligence

A Symbolic Model Checking Framework for Safety Analysis, Diagnosis, and Synthesis.- Verifying Space and Time Requirements for Resource-Bounded Agents.- Automated Creation of Pattern Database Search Heuristics.- Using Predicate Abstraction to Generate Heuristic Functions in UPPAAL.- Real-Time Model Checking on Secondary Storage.- Checking Liveness Properties of Concurrent Systems by Reinforcement Learning.- Bounded Model Checking Real-Time Multi-agent Systems with Clock Differences: Theory and Implementation.- Symbolic Model Checking of Logics with Actions.- A Framework for Model Checking Institutions.- SAT-Based Verification of Security Protocols Via Translation to Networks of Automata.- Distributed Extended Beam Search for Quantitative Model Checking.

Model checking knowledge, strategies, and games in multi-agent systems

We present an OBDD-based methodology for verifying time, knowledge, and strategies in multi-agent systems specified by the formalism of interpreted systems. To this end, we investigate the interpretation of ATL and epistemic formulae in various classes of interpreted systems, we present model checking algorithms and their implementation, and report experimental results.

Towards verifying contract regulated service composition

We report on a novel approach to (semi-)automatically compile and verify contract-regulated service compositions implemented as multi-agent systems. We model web service behaviours and the contracts governing them as WSBPEL specification. We use the formalism of temporal-epistemic logic, suitably extended to deal with compliance/violations of contracts, to specify properties of service compositions. We compile the WSBPEL behaviours into a specialised system description language ISPL, to be used with the model checker MCMAS to verify the behaviours automatically. We illustrate these concepts using a motivating example whose state space is approximately 106 and discuss experimental results.