Publications
145 results found
Artikis A, Sergot M, Pitt J, 2009, Specifying Norm-Governed Computational Societies, ACM Transactions on Computational Logic, Vol: 10, Pages: 1-42
Barker S, Sergot MJ, Wijesekera D, 2008, Status-Based Access Control, ACM TRANSACTIONS ON INFORMATION AND SYSTEM SECURITY, Vol: 12, ISSN: 1094-9224
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- Citations: 13
Craven R, Sergot MJ, 2008, Agent strands in the action language nC+., Journal of Applied Logic, Vol: 6, Pages: 172-191, ISSN: 1570-8683
Sergot M, 2008, The logic of unwitting collective agency, Departmental Technical Report: 08/6, Publisher: Department of Computing, Imperial College London, 08/6
The paper is about the logic of expressions of the form `agent x bringsit about that A is the case', or `agent x is responsible for its being thecase that A', or `the actions of agent x are the cause of its being thecase that A'. Agents could be deliberative (human or computer) agents,purely reactive agents, or simple computational devices. The `brings itabout' modalities are intended to express unintentional, perhaps even accidental,consequences of an agent's actions, as well as possibly intentional(intended) ones. Since we make no assumptions at all about the reasoningor perceptual capabilities of the agents we refer to this form of agency as`unwitting'; unwitting can mean both inadvertent and unaware. The semanticalframework is a form of labelled transition system extended withan extra component that picks out the actions of a particular agent ina transition, or its `strand' as we call it. We de ne a modal languagefor talking about the actions of individual agents or groups of agents intransitions, including two de ned modalities of the (unwitting) `brings itabout' kind. The novel feature is the switch of attention from talkingabout an agent's bringing it about that a certain state of a airs existsto talking about an agent's bringing it about that a transition has a certainproperty. The middle part of the paper presents axiomatisations ofthe logic, and comments on relationships to other work, in particular onresemblances to Porn's (1977) logic of `brings it about'. The last partis concerned with characterisations of (unwitting) collective agency, thatis, the logic of expressions of the form `the set G of agents, collectivelythough perhaps unwittingly, brings it about that A'.
Artikis A, Sergot M, 2008, Executable specication of open multi-agent systems, Departmental Technical Report: 08/17, Publisher: Department of Computing, Imperial College London, 08/17
Multi-agent systems where the agents are developed by parties with competing interests, and wherethere is no access to an agent's internal state, are often classi ed as `open'. The members of such systems mayinadvertently fail to, or even deliberately choose not to, conform to the system speci cation. Consequently, it isnecessary to specify the normative relations that may exist between the members, such as permission, obligation,and institutional power. We present a framework being developed for executable speci cation of open multi-agentsystems. We adopt a bird's eye view of these systems, as opposed to an agent's perspective whereby it reasonsabout how it should act. This paper is devoted to the presentation of various examples from the NetBill protocolformalised in terms of institutional power, permission and obligation. We express the system speci cation inthe Event Calculus and execute the speci cation by means of a logic programming implementation. We alsogive several example formalisations of sanctions for dealing with violations of permissions and obligations. Wedistinguish between an open multi-agent system and the procedure by which an agent enters and leaves thesystem. We present examples from the speci cation of a role-management protocol for NetBill, and demonstratethe interplay between such a protocol and the corresponding multi-agent system.
Sergot M, 2008, Action and Agency in Norm-Governed Multi-agent Systems, 8th International Workshop on Engineering Societies in the Agents World, Publisher: SPRINGER-VERLAG BERLIN, Pages: 1-54, ISSN: 0302-9743
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- Citations: 12
Artikis A, Sergot M, Pitt JV, 2007, An Executable Specification of a Formal Argumentation Protocol, Artificial Intelligence Journal, Vol: 171, Pages: 776-804
We present a specification, in the action language C+, of Brewka's reconstruction of a theory of formal disputation originally proposed by Rescher. The focus is on the procedural aspects rather than the adequacy of this particular protocol for the conduct of debate and the resolution of disputes. The specification is structured in three separate levels, covering (i) the physical capabilities of the participant agents, (ii) the rules defining the protocol itself, specifying which actions are ‘proper’ and ‘timely’ according to the protocol and their effects on the protocol state, and (iii) the permissions, prohibitions, and obligations of the agents, and the sanctions and enforcement strategies that deal with non-compliance. Also included is a mechanism by which an agent may object to an action by another participant, and an optional ‘silence implies consent’ principle. Although comparatively simple, Brewka's protocol is thus representative of a wide range of other more complex argumentation and dispute resolution procedures that have been proposed. Finally, we show how the ‘Causal Calculator’ implementation of C+ can be used to animate the specification and to investigate and verify properties of the protocol.
Farrell ADH, Sergot MJ, 2007, Formalising workflow: A CCS-inspired characterisation of the YAWL workflow patterns, 11th FMEC Workshop 2005, Publisher: SPRINGER, Pages: 213-254, ISSN: 0926-2644
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- Citations: 8
Lomuscio A, Qu H, Sergot M, et al., 2007, Verifying temporal and epistemic properties of web service compositions, 5th International Conference on Service-Oriented Computing (ICSOC 2007), Publisher: SPRINGER-VERLAG BERLIN, Pages: 456-+, ISSN: 0302-9743
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- Citations: 6
Sergot M, Craven RA, 2006, The Deontic Component of Action Language nC+, DEON 2006, Pages: 222-237
Sergot M, Craven RA, 2006, The Deontic Component of Action Language nC+, DEON 2006, Pages: 222-237
Jefferys BR, Kelley LA, Sergot MJ, et al., 2006, Capturing expert knowledge with argumentation: a case study in bioinformatics, BIOINFORMATICS, Vol: 22, Pages: 924-933, ISSN: 1367-4803
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- Citations: 12
Gaertner D, Clark K, Sergot M, 2006, Ballroom etiquette: a case study for norm-governed multi-agent systems, Coordination, Organization, Institutions and Norms in Agent Systems, Publisher: International Conference on Autonomous agents multi-agent systems
Gaertner D, Clark K, Sergot M, 2006, Ballroom etiquette: a case study for norm-governed multi-agent systems, Coordination, Organization, Institutions and Norms in Agent Systems, Publisher: International Conference on Autonomous agents multi-agent systems
Pitt J, Kamara L, Sergot M, et al., 2006, Voting in multi-agent systems, COMPUTER JOURNAL, Vol: 49, Pages: 156-170, ISSN: 0010-4620
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- Citations: 37
Huntley D, Baldo A, Johri S, et al., 2006, SEAN: SNP prediction and display program utilizing EST sequence clusters, BIOINFORMATICS, Vol: 22, Pages: 495-496, ISSN: 1367-4803
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- Citations: 28
Artikis A, Sergot M, Pitt J, 2006, Specifying norm-governed computational societies, Departmental Technical Report: 06/5, Publisher: Department of Computing, Imperial College London, 06/5
Electronic markets, dispute resolution and negotiation protocols are three typesof application domains that can be viewed as open agent societies. Key characteristicsof such societies are agent heterogeneity, conflicting individual goals andunpredictable behaviour. Members of such societies may fail to, or even choosenot to, conform to the norms governing their interactions. It has been argued thatsystems of this type should have a formal, declarative, verifiable, and meaningfulsemantics. We present a theoretical and computational framework being developedfor the executable specification of open agent societies. We adopt an externalperspective and view societies as instances of normative systems. In this paperwe demonstrate how the framework can be applied to specifying and executinga contract-net protocol. The specification is formalised in two action languages,the C+ language and the Event Calculus, and executed using respective softwareimplementations, the Causal Calculator and the Society Visualiser. We evaluateour executable specification in the light of the presented case study, discussing thestrengths and weaknesses of the employed action languages for the specification ofopen agent societies.
Rissanen E, Firozabadi BS, Sergot M, 2006, Towards a mechanism for discretionary overriding of access control, 12th International Workshop on Security Protocols, Publisher: SPRINGER-VERLAG BERLIN, Pages: 312-323, ISSN: 0302-9743
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- Citations: 7
Kamara L, Pitt J, Sergot M, 2005, Towards norm-governed self-organising networks, Pages: 137-148
Ad hoc networks may be viewed as computational systems whose members may fail to, or choose not to, comply with the rules governing participation. From this perspective, there is a need for mechanisms to model, monitor and manage interactions in these networks in order to promote their smooth running and correct operation. We propose a norm-governed approach to satisfy these requirements, comprising an agent architecture with an objective reasoning capacity (allowing agents to reason about normative positions) and a suite of protocols for network management. In this paper, we describe a corresponding system architecture that, if successful, will lead to ad hoc networks capable of demonstrating self-organising behaviour in accordance with external system and normative specifications.
Pitt J, Kamara L, Sergot M, et al., 2005, Formalization of a voting protocol for virtual organizations, Pages: 511-518
A voting protocol for decision-making in virtual organizations is presented. In an agent-based virtual organization the functions of formation, management and dissolution of the organization are passed to software processes. Each phase in this life-cycle requires decision making: An ostensibly fair way for independent agents to make decisions is to take a vote. Accordingly, this paper formalizes a protocol for voting. The emphasis is on characterising the powers, permissions, obligations and even sanctions of the voters, using a norm-governed approach to agent societies. The specification language is the Event Calculus, and its animation is informative with respect to a full implementation. It is wellknown that various types of ad hoc alliance of autonomous entities require voting procedures, and a normative specification of the interactions is therefore beneficial for many aspects of self-organization and self-management. Copyright 2005 ACM.
Craven RA, Sergot M, 2005, Distant causation in C+, Studia Logica, Vol: 79, Pages: 73-96, ISSN: 0039-3215
Papatheodorou I, Kakas A, Sergot M, 2005, Inference of gene relations from microarray data by abduction, Departmental Technical Report: 05/3, Publisher: Department of Computing, Imperial College London, 05/3
We describe an application of Abductive Logic Programming(ALP) to the analysis of an important class of DNA microarrayexperiments. These experiments measure di erences in expression levelsof whole genomes in di ering environmental conditions and/or afterdeletion or overexpression of one or more genes. Their aim is to obtaininsights about gene interactions and gene pathways. We developan ALP theory that provides a simple and general model of how geneinteractions can cause changes in observable expression levels of genes.Input to the procedure are the observed microarray results; output arehypotheses about possible gene interactions that explain the observede ects. A key feature of the model are parameters that encode di erentbiological assumptions and provide a means of constraining the searchfor possible hypotheses. We have applied and evaluated our approach onmicroarray experiments on M.tuberculosis and on S.cerevisiae (yeast).Comparison of inferred hypotheses against known gene regulation networksand known gene functions in the biological literature provide aform of independent validation of the model.
Craven R, Sergot M, 2005, Logical properties of nonmonotonic causal theories and the action language C+, Departmental Technical Report: 05/5, Publisher: Department of Computing, Imperial College London, 05/5
The formalism of nonmonotonic causal theories (Giunchiglia, Lee, Lifschitz,McCain, Turner, 2004) provides a general-purpose formalism for nonmonotonicreasoning and knowledge representation, as well as a higher level,special-purpose notation, the action language C+, for specifying and reasoningabout the e ects of actions and the persistence (`inertia') of factsover time. In this paper we investigate some logical properties of these formalisms.There are two motivations. From the technical point of view, weseek to gain additional insights into the properties of the languages whenviewed as a species of conditional logic. From the practical point of view,we are seeking to nd conditions under which two di erent causal theories,or two di erent action descriptions in C+, can be said to be equivalent, withthe further aim of helping to decide between alternative formulations whenconstructing practical applications.A condensed version of this paper appeared as `Some logical properties ofnonmonotonic causal theories', Proc. Eighth International Conference onLogic Programming and Non-Monotonic Reasoning, LNCS, Springer.
Pitt JV, Kamara LD, Sergot MJ, et al., 2005, Formalization of a voting protocol for virtual organizations, 4th international joint conference on Autonomous agents and multiagent systems (AAMAS 2005), 25 - 29 July 2005, The Netherlands, Publisher: ACM Press, Pages: 373-380
Papatheodorou I, Kakas A, Sergot M, 2005, Inference of gene relations from microarray data by abduction, Berlin, 8th International Conference on Logic Programming and Nonmonotonic Reasoning, 5 - 8 September 2005, Diamante, Italy, Publisher: Springer-Verlag, Pages: 389-393
Sergot M, 2005, Modelling unreliable and untrustworthy agent behaviour, Berlin, International workshop on monitoring, security, and rescue technique in multiagent systems, Plock, Poland, 7 - 9 June 2004, Publisher: Springer-Verlag, Pages: 161-177
Artikis A, Kamara L, Pitt J, et al., 2005, A protocol for resource sharing in norm-governed ad hoc networks, 2nd International Workshop on Declarative Agent Languages and Technologies, Publisher: SPRINGER-VERLAG BERLIN, Pages: 221-238, ISSN: 0302-9743
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- Citations: 18
Pitt JV, Kamara LD, Sergot MJ, et al., 2005, Voting in online deliberative assemblies, International conference on artificial intelligence (ICAIL 05), 6-11 June 2005, Spain, Pages: 195-204
Pitt JV, Kamara LD, Sergot MJ, et al., 2005, Formalization of a voting protocol for virtual organizations, 4th international joint conference on Autonomous agents and multiagent systems (AAMAS 2005), 25 - 29 July 2005, The Netherlands, Publisher: ACM Press, Pages: 373-380
Sergot M, Craven R, 2005, Some logical properties of nonmonotonic causal theories, Berlin, 8th International Conference on Logic Programming and Nonmonotonic Reasoning, 5 - 8 September 2005, Diamante, Italy, Publisher: Springer-Verlag, Pages: 198-210
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