Authors: Ji Ruan and Michael Thielscher
School of Computer Science and Engineering, The University of New South Wales, Australia

Abstract: In this paper, we develop a formal framework for analysing the flow of information and knowledge through social networks. More specifically, we propose a multi-agent epistemic logic in which we can represent and reason about communicative actions based on social networks and the resulting knowledge and ignorance of agents. This logic is applied to formally analyse the “Revolt or Stay-at-home” problem where social networks play an important role in agents’ knowledge acquisition and decision-making. We evaluate our work by proving some mathematical properties of our new logic, including the fact that it generalises the existing Logic of Public Announcement.

Accepted and presented at the 24th Australasian Joint Conference on Artificial Intelligence (AI2011), Perth Australia, December 2011.

Download:

• Springer
• Camera Ready Version.

Bibtex:

@inproceedings{DBLP:conf/ausai/RuanT11,
author = {Ji Ruan and
Michael Thielscher},
title = {A Logic for Knowledge Flow in Social Networks},
booktitle = {Australasian Conference on Artificial Intelligence},
year = {2011},
pages = {511-520},
ee = {http://dx.doi.org/10.1007/978-3-642-25832-9_52},
crossref = {DBLP:conf/ausai/2011},
bibsource = {DBLP, http://dblp.uni-trier.de}
}
@proceedings{DBLP:conf/ausai/2011,
editor = {Dianhui Wang and
Mark Reynolds},
title = {AI 2011: Advances in Artificial Intelligence – 24th Australasian
Joint Conference, Perth, Australia, December 5-8, 2011.
Proceedings},
booktitle = {Australasian Conference on Artificial Intelligence},
publisher = {Springer},
series = {Lecture Notes in Computer Science},
volume = {7106},
year = {2011},
isbn = {978-3-642-25831-2},
ee = {http://dx.doi.org/10.1007/978-3-642-25832-9},
bibsource = {DBLP, http://dblp.uni-trier.de}
}

Related posts:

1. Conference paper: The Epistemic Logic Behind the Game Description Language Title: The Epistemic Logic Behind the Game Description Language Authors:...
2. Journal paper: Connecting Dynamic Epistemic and Temporal Epistemic Logics Title: Connecting Dynamic Epistemic and Temporal Epistemic Logics Authors: H.P. van Ditmarsch,...

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Authors: H.P. van Ditmarsch, W. van der Hoek, and J. Ruan.

Abstract: We give a relation between a logic of knowledge and change, with a semantics on Kripke models, and a logic of knowledge and time, with a semantics on interpreted systems. In particular, given an epistemic state (pointed Kripke model with equivalence relations) and a formula in a dynamic epistemic logic (a logic describing the consequences of epistemic actions), we construct an interpreted system relative to that epistemic state and that formula that satisfies the translation of the formula into a temporal epistemic logic. The construction involves that the protocol that is implicit in the dynamic epistemic formula, i.e., the set of sequences of actions being executed to evaluate the formula, is made explicit. We first focus on the logic of knowledge and change that is known as public announcement logic, then generalize our results to a dynamic epistemic logic.

It is published in The Logic Journal of the IGPL.
http://jigpal.oxfordjournals.org/content/early/2011/10/27/jigpal.jzr038.refs

PDF:
http://jigpal.oxfordjournals.org/content/early/2011/10/27/jigpal.jzr038.full.pdf+html

Prepublication version.

It is an extended version of this workshop paper.

The paper was first submitted when I was still at the University of Liverpool (UK) in 2009; the revision was made when I was at the StFX University (Canada) in 2010, and finally accepted when I moved to the current University of New South Wales (Australia) in 2011.

Related posts:

1. Conference paper: The Epistemic Logic Behind the Game Description Language Title: The Epistemic Logic Behind the Game Description Language Authors:...

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Authors:
Ji Ruan and Michael Thielscher
School of Computer Science and Engineering The University of New South Wales, Australia

Abstract:
A general game player automatically learns to play arbitrary new games solely by being told their rules. For this purpose games are specified in the game description language GDL, a variant of Datalog with function symbols and a few known keywords. In its latest version GDL allows to describe nondeterministic games with any number of players who may have imperfect, asymmetric information. We analyse the epistemic structure and expressiveness of this language in terms of epistemic modal logic and present two main results: (1) The operational semantics of GDL entails that the situation at any stage of a game can be characterised by a multi-agent epistemic (i.e., S5-) model; (2) GDL is sufficiently expressive to model any situation that can be described by a (finite) multi- agent epistemic model.

Status:

Presented at the Twenty-Fifth Conference on Artificial Intelligence, AAAI-11. (San Francisco, USA).

Download: Camera Ready Version, AAAI Web Version.

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Download: PDF.

Abstract:

This paper presents an approach to monitor healthcare workflows using a logic-based formal method. We introduce a monitoring architecture with workflows and knowledge bases, and propose a logical language, FO-LTL-K, to express temporal and knowledge properties to be monitored. We formalize some of the norms for palliative care using the proposed logic and characterize the complexity of the model checking problem.

Keywords: Data and knowledge integration, Temporal knowledge representations, Logic-based methods, Ontologies, Complexity.

Accepted by the Second International Workshop on Knowledge Representation for Health Care (KR4HC-2010), Lisbon, Portugal, August 2010.

I presented it on August 17, 2010 in Lisbon. Here is a photo of me:
.

Group photo of the workshop:

Link to the full photo album.

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Download: PDF.

Abstract:

In this paper, we propose the use of an agent-based architecture to enhance workflow system capacity to support interprofessional, patient-centred palliative care delivery. This paper outlines the concept of palliative care and describes how agents can be used to assist care providers to address the needs of the patient and family. Our architecture is illustrated in a diagram and the agents are described in terms of the services they provide, and the dependencies among them. The dependencies determine the information flow, which facilitates the communication and collaboration among the patient and care providers.

Keywords: Agent-based Modelling; Patient-centred Healthcare; Palliative Care; Collaboration; Team Approach

Accepted by the Second International Workshop on Collaborative Agents – REsearch and Development (CARE 2010), Toronto, Canada, August 2010.

Here is a photo of me presenting this paper:

Group photo:

Link to the full photo album.

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Authors: Ji Ruan, Wiebe van der Hoek, and Michael Wooldridge

Abstract: The Game Description Language (GDL) is a special purpose declarative language for defining games. GDL is used in the AAAI General Game Playing Competition, which tests the ability of computer programs to play games in general, rather than just the ability to play a specific game. Participants in the competition are provided with a previously unknown game specified in GDL, and are required to dynamically and autonomously determine how best to play this game. Recently, there has been much interest in the use of strategic cooperation logics for reasoning about game-like scenarios – the Alternating-time Temporal Logic (ATL) of Alur, Henzinger, and Kupferman is perhaps the best known example. Such logics are specifically intended to support reasoning about game-theoretic properties of multi-agent systems. In short, the aim of this article is to make a concrete link between ATL and GDL, with the ultimate goal of using ATL to reason about GDL-specified games. We make the following contributions. First, we demonstrate that GDL can be understood as a specification language for ATL models, and prove that the problem of interpreting ATL formulae over propositional GDL descriptions is EXPTIME-complete. Second, we use ATL to characterize a class of ‘fair playability’ conditions, which might or might not hold of various games.

Keywords: Verification, general game playing, game description language, alternating-time temporal logic, model checking.

Link to an online version: http://portal.acm.org/citation.cfm?id=1666968.1666995&coll=&dl=

Bibtex:

@article{RuanHW:2009JLC,
author = {Ruan, Ji and van der Hoek, Wiebe and Wooldridge, Michael},
title = {Verification of Games in the Game Description Language},
journal = {J. Log. and Comput.},
volume = {19},
number = {6},
year = {2009},
issn = {0955-792X},
pages = {1127–1156},
doi = {http://dx.doi.org/10.1093/logcom/exp039},
publisher = {Oxford University Press},
address = {Oxford, UK},
}

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Here is the preview version (final draft). The first version was submitted on 8th August, 2008.

Jane’s notification:

Dear Ji Ruan

I’m writing about the revised version of your submission to the Agents Corner of the Journal of Logic and Computation, ‘Verification of Games in the Game Description Language’,  JLC 08-37.

Both referees have approved the revised version and, therefore, the editors have accepted the paper for publication.

Please will you send me the final files – I will need source file(s) and corresponding pdf, which OUP will prepare for publication.

Sincerely
Jane Spurr

–

Department of Computer Science,            tel: + (0)20 7848 2987
King’s College, Strand,                    fax: + (0)20 7240 1071
London WC2R 2LS.

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Reasoning about Time, Action and Knowledge in Multi-Agent Systems

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jiblog-in-china, originally uploaded by jiruan.

I am now in a netbar in Shanghai. The above screen copy shows my blog is not accessible in China.

The GFW (Great Fire
Wall) is responsible for that. I am glad that we have such a ‘wonderful’ thing in China.

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July 2009 Update: This paper has been accepted by the JLC.

March 2009 Update: The Journal of Logic and Computation (JLC) has sent us back the reviews, and we need a revision before it gets accepted.

–

This is a joint work with my PhD supervisors Wiebe van der Hoek and Michael Wooldridge.

It is submitted to the Journal of Logic and Computation. Comments are very welcomed and please contact ji@jiruan.net ( or j.ruan@csc.liv.ac.uk as listed in the paper).

Abstract:

The Game Description Language (GDL) is a special purpose declarative language for defining games. GDL is used in the AAAI General Game Playing Competition, which tests the ability of computer programs to play games in general, rather than just the ability to play a specific game. Participants in the competition are provided with a previously unknown game specified in GDL, and are required to dynamically and autonomously determine how best to play this game. Recently, there has been much interest in the use of strategic cooperation logics for reasoning about game-like scenarios — the Alternating-time Temporal Logic (ATL) of Alur, Henzinger, and Kupferman is perhaps the best known example. Such logics are specifically intended to support reasoning about game-theoretic properties of multi-agent systems. In short, the aim of this article is to make a concrete link between ATL and GDL, with the ultimate goal of using ATL to reason about GDL-specified games.  We make three main contributions. First, we demonstrate that GDL can be understood as a specification language for ATL models, and prove that the problem of interpreting ATL formulae over propositional GDL descriptions is EXPTIME-complete. Second, we use ATL to characterize a class of “fair playability” conditions, which might or might not hold of various games. Third, we describe an automated tool that transforms a GDL description into RML, the model description language for the Mocha model checker, thereby permitting the use of Mocha for verifying playability properties on the RML description. We also present some experimental results on the use of this tool.

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