special section – uncertain reasoning track flairs 2009

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Editorial Special section – Uncertain reasoning track FLAIRS 2009 This section includes extended versions of a selection of the best papers presented at the special track on uncertain rea- soning (UR) at the Florida Artificial Intelligence Research Society Conference (FLAIRS-22), 2009. The UR track is the oldest track in FLAIRS conferences, running annually since 1996; UR’09 was the 14th in the series. UR’09 brought together research- ers working on broad issues related to reasoning under uncertainty. Through rigorous reviews by the program committee, UR’09 accepted 9 full papers and 4 posters from 18 submissions. These papers gave a broad and diverse sample of current work on uncertain reasoning, including theoretical and applied research based on different paradigms. From the papers presented at FLAIRS’09, the UR track chairs selected the best ones and asked the authors to submit extended and updated versions. These went through a second round of a thorough review process, resulting in the four articles included in this special section. The work presented includes developments on propagation in Bayesian networks, multi-agents in dynamic systems, Bayesian knowledge fusion, and belief revision. An overview of the four papers in this special section follows. Efficient inference methods are a critical aspect for practical applications of Bayesian networks. Current direct computa- tions are often based on variable elimination (VE) or arc reversal (AR). Butz and Konkel develop a method that combines both techniques during the inference process, selecting dynamically either VE or AR to build the messages propagated in a join tree. In a pre-processing step they determine the messages to be propagated, and then they select VE or AR according to the type of computation required in each node. In an empirical evaluation they show that selectively applying VA and AR is fas- ter than using only one of these methods. A popular approach to modelling uncertainity in time series data is to use dynamic Bayesian networks (DBNs). In their paper, Xiang, Smith, and Kroes extend the current DBN architecture to use multiply-sectioned Bayesian networks as their underlying model. This new model, called a dynamic multiply sectioned Bayesian network (DMSBN), allows the DBN to be represented as a set of distributed, cooperative agents, each containing potentially proprietary information. Of particular interest is the efficiency and accuracy of this approach: using a real-world domain, the DMSBN was shown to be more accurate than a standard DBN, as well as exponentially faster than a DBN under the assumption of structural time invariance. In certain knowledge representation applications, there are several sources of available information. The information from each source must somehow be combined, and this problem may be further complicated by uncertain information or unreliable sources. The paper by Santos, Wilkinson, and Santos presents a new approach to this problem by representing each information source as a Bayesian knowledge base, and then fusing these knowledge bases together using a novel tech- nique called Bayesian knowledge fusion. This approach allows explicit representation of both uncertainty and reliability using parameters. The model is very flexible, permitting disagreement between information sources on the probabilities and/or causality of events. One particularly attractive property of this approach is that the individual contributions of each information source are preserved in the aggregated model. The process by which an agent revises its beliefs when it receives new evidence is known as belief revision. Throughout this process, the agent accommodates new evidence to reach a set of consistent beliefs. Ma and Liu investigate the case when the new evidence and the current beliefs are not consistent, so that a belief change is required. In particular, they follow the principle in which the outcome of belief change depends on the strength of the new evidence. They develop a set of postu- lates for the role of strengths in determining the outcome of the revision process; and proposed a novel merging operator characterised by this postulates, which solves the belief revision process based on the strength of the evidence. We appreciate the dedication and professional work of all the reviewers of this special section, and the patience and guid- ance of Thierry Denoeux, the Editor in Chief. 0888-613X/$ - see front matter Ó 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.ijar.2011.06.007 International Journal of Approximate Reasoning 52 (2011) 915–916 Contents lists available at ScienceDirect International Journal of Approximate Reasoning journal homepage: www.elsevier.com/locate/ijar

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Page 1: Special section – Uncertain reasoning track FLAIRS 2009

International Journal of Approximate Reasoning 52 (2011) 915–916

Contents lists available at ScienceDirect

International Journal of Approximate Reasoning

journal homepage: www.elsevier .com/locate / i jar

Editorial

Special section – Uncertain reasoning track FLAIRS 2009

This section includes extended versions of a selection of the best papers presented at the special track on uncertain rea-soning (UR) at the Florida Artificial Intelligence Research Society Conference (FLAIRS-22), 2009. The UR track is the oldesttrack in FLAIRS conferences, running annually since 1996; UR’09 was the 14th in the series. UR’09 brought together research-ers working on broad issues related to reasoning under uncertainty.

Through rigorous reviews by the program committee, UR’09 accepted 9 full papers and 4 posters from 18 submissions.These papers gave a broad and diverse sample of current work on uncertain reasoning, including theoretical and appliedresearch based on different paradigms. From the papers presented at FLAIRS’09, the UR track chairs selected the best onesand asked the authors to submit extended and updated versions. These went through a second round of a thorough reviewprocess, resulting in the four articles included in this special section.

The work presented includes developments on propagation in Bayesian networks, multi-agents in dynamic systems,Bayesian knowledge fusion, and belief revision. An overview of the four papers in this special section follows.

Efficient inference methods are a critical aspect for practical applications of Bayesian networks. Current direct computa-tions are often based on variable elimination (VE) or arc reversal (AR). Butz and Konkel develop a method that combines bothtechniques during the inference process, selecting dynamically either VE or AR to build the messages propagated in a jointree. In a pre-processing step they determine the messages to be propagated, and then they select VE or AR according to thetype of computation required in each node. In an empirical evaluation they show that selectively applying VA and AR is fas-ter than using only one of these methods.

A popular approach to modelling uncertainity in time series data is to use dynamic Bayesian networks (DBNs). In theirpaper, Xiang, Smith, and Kroes extend the current DBN architecture to use multiply-sectioned Bayesian networks astheir underlying model. This new model, called a dynamic multiply sectioned Bayesian network (DMSBN), allows theDBN to be represented as a set of distributed, cooperative agents, each containing potentially proprietary information. Ofparticular interest is the efficiency and accuracy of this approach: using a real-world domain, the DMSBN was shown tobe more accurate than a standard DBN, as well as exponentially faster than a DBN under the assumption of structural timeinvariance.

In certain knowledge representation applications, there are several sources of available information. The informationfrom each source must somehow be combined, and this problem may be further complicated by uncertain informationor unreliable sources. The paper by Santos, Wilkinson, and Santos presents a new approach to this problem by representingeach information source as a Bayesian knowledge base, and then fusing these knowledge bases together using a novel tech-nique called Bayesian knowledge fusion. This approach allows explicit representation of both uncertainty and reliabilityusing parameters. The model is very flexible, permitting disagreement between information sources on the probabilitiesand/or causality of events. One particularly attractive property of this approach is that the individual contributions of eachinformation source are preserved in the aggregated model.

The process by which an agent revises its beliefs when it receives new evidence is known as belief revision. Throughoutthis process, the agent accommodates new evidence to reach a set of consistent beliefs. Ma and Liu investigate the case whenthe new evidence and the current beliefs are not consistent, so that a belief change is required. In particular, they follow theprinciple in which the outcome of belief change depends on the strength of the new evidence. They develop a set of postu-lates for the role of strengths in determining the outcome of the revision process; and proposed a novel merging operatorcharacterised by this postulates, which solves the belief revision process based on the strength of the evidence.

We appreciate the dedication and professional work of all the reviewers of this special section, and the patience and guid-ance of Thierry Denoeux, the Editor in Chief.

0888-613X/$ - see front matter � 2011 Elsevier Inc. All rights reserved.doi:10.1016/j.ijar.2011.06.007

Page 2: Special section – Uncertain reasoning track FLAIRS 2009

916 Editorial / International Journal of Approximate Reasoning 52 (2011) 915–916

Kevin GrantDepartment of Mathematics and Computer Science, University of Lethbridge, Canada

E-mail address: [email protected]

L. Enrique SucarDepartment of Computer Science, National Institute for Astophysics,

Optics and Electronics, MexicoE-mail address: [email protected]

Available online 4 August 2011