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Obtaining Solutions in Fuzzy Constraint Networks
 International Journal of Approximate Reasoning
, 1997
"... In this work we propose three methods for obtaining solutions in fuzzy constraint networks and study their application to the problem of ordering fuzzy numbers. The techniques proposed may be classified as defuzzification functions which are applicable to any set of mutually dependant fuzzy numbers ..."
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Cited by 17 (2 self)
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In this work we propose three methods for obtaining solutions in fuzzy constraint networks and study their application to the problem of ordering fuzzy numbers. The techniques proposed may be classified as defuzzification functions which are applicable to any set of mutually dependant fuzzy numbers in which the dependence relationships are represented by means of metric constraints. In the paper we suggest the use of these techniques for ordering linked variables in an efficient manner, and discuss their behavior regarding several quality criteria. The first application realm of these techniques is temporal reasoning.
Uncertainty in soft temporal constraint problems: a general framework and controllability algorithms for the fuzzy case
 Journal of AI Research
, 2006
"... In reallife temporal scenarios, uncertainty and preferences are often essential and coexisting aspects. We present a formalism where quantitative temporal constraints with both preferences and uncertainty can be defined. We show how three classical notions of controllability (that is, strong, weak, ..."
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Cited by 15 (3 self)
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In reallife temporal scenarios, uncertainty and preferences are often essential and coexisting aspects. We present a formalism where quantitative temporal constraints with both preferences and uncertainty can be defined. We show how three classical notions of controllability (that is, strong, weak, and dynamic), which have been developed for uncertain temporal problems, can be generalized to handle preferences as well. After defining this general framework, we focus on problems where preferences follow the fuzzy approach, and with properties that assure tractability. For such problems, we propose algorithms to check the presence of the controllability properties. In particular, we show that in such a setting dealing simultaneously with preferences and uncertainty does not increase the complexity of controllability testing. We also develop a dynamic execution algorithm, of polynomial complexity, that produces temporal plans under uncertainty that are optimal with respect to fuzzy preferences. 1.
Controllability of soft temporal constraint problems
 In Proc. of CP’04, LNCS 3258
, 2004
"... Abstract. In reallife temporal scenarios, uncertainty and preferences are often essential, coexisting aspects. We present a formalism where temporal constraints with both preferences and uncertainty can be defined. We show how three classical notions of controllability (strong, weak and dynamic), w ..."
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Cited by 14 (7 self)
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Abstract. In reallife temporal scenarios, uncertainty and preferences are often essential, coexisting aspects. We present a formalism where temporal constraints with both preferences and uncertainty can be defined. We show how three classical notions of controllability (strong, weak and dynamic), which have been developed for uncertain temporal problems, can be generalised to handle also preferences. We then propose algorithms that check the presence of these properties and we prove that, in general, dealing simultaneously with preferences and uncertainty does not increase the complexity beyond that of the separate cases. In particular, we develop a dynamic execution algorithm, of polynomial complexity, that produces plans under uncertainty that are optimal w.r.t. preference. 1
Fuzziness and uncertainty in temporal reasoning
 Journal of Universal Computer Science
, 2003
"... Abstract: This paper proposes a general discussion of the handling of imprecise and uncertain information in temporal reasoning in the framework of fuzzy sets and possibility theory. The introduction of fuzzy features in temporal reasoning can be related to different issues. First, it can be motivat ..."
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Cited by 14 (0 self)
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Abstract: This paper proposes a general discussion of the handling of imprecise and uncertain information in temporal reasoning in the framework of fuzzy sets and possibility theory. The introduction of fuzzy features in temporal reasoning can be related to different issues. First, it can be motivated by the need of a gradual, linguisticlike description of temporal relations even in the face of complete information. An extension of Allen relational calculus is proposed, based on fuzzy comparators expressing linguistic tolerance. Fuzzy Allen relations are defined from a fuzzy partition made by three possible fuzzy relations between dates (approximately equal, clearly smaller, and clearly greater). Second, the handling of fuzzy or incomplete information leads to pervade classical Allen relations, and more generally fuzzy Allen relations, with uncertainty. The paper provides a detailed presentation of the calculus of fuzzy Allen relations (including the composition table of these relations). Moreover, the paper discusses the patterns for propagating uncertainty about (fuzzy) Allen relations in a possibilistic way.
Fuzzy Temporal/Categorical Information in Diagnosis
 Journal of Intelligent Information Systems
, 1999
"... . This paper proposes a way of incorporating fuzzy temporal reasoning within diagnostic reasoning. Disorders are described as an evolving set of necessary and possible manifestations. Illknown moments in time, e.g. when a manifestation should start or end, are modeled by fuzzy intervals, which are ..."
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Cited by 11 (1 self)
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. This paper proposes a way of incorporating fuzzy temporal reasoning within diagnostic reasoning. Disorders are described as an evolving set of necessary and possible manifestations. Illknown moments in time, e.g. when a manifestation should start or end, are modeled by fuzzy intervals, which are also used to model the elapsed time between events, e.g. the beginning of a manifestation and its end. Patient information about the intensity and times in which manifestations started and ended are also modeled using fuzzy sets. The paper discusses many measures of consistency between the patient's data and the disorder model, and defines when the manifestations of the patient can be explained by a disorder. This work also discusses related issues such as the intensity of manifestations and the speed in which the disorder is evolving, given the patient's data, and how to use that information to make predictions about future and past events. 1. Introduction Temporal information and tempor...
Learning and Solving Soft Temporal Constraints: An Experimental Study
 In Proceedings of the Eighth International Conference on Principles and Practice of Constraint Programming
, 2002
"... Soft temporal constraints problems allow for a natural description of scenarios where events happen over time and preferences are associated with event distances and durations. However, sometimes such local preferences are dicult to set, and it may be easier instead to associate preferences to s ..."
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Cited by 11 (6 self)
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Soft temporal constraints problems allow for a natural description of scenarios where events happen over time and preferences are associated with event distances and durations. However, sometimes such local preferences are dicult to set, and it may be easier instead to associate preferences to some complete solutions of the problem, and then to learn from them suitable preferences over distances and durations.
Computational treatment of temporal notions – the CTTNsystem
 Principles and Practice of Semantic Web Reasoning (PPSWR2005). Volume 3703 of LNCS
, 2005
"... Abstract. The CTTN–system is a computer program which provides advanced processing of temporal notions. The basic data structures of the CTTN–system are time points, crisp and fuzzy time intervals, labelled partitionings of the time line, durations, and calendar systems. The labelled partitionings ..."
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Cited by 5 (4 self)
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Abstract. The CTTN–system is a computer program which provides advanced processing of temporal notions. The basic data structures of the CTTN–system are time points, crisp and fuzzy time intervals, labelled partitionings of the time line, durations, and calendar systems. The labelled partitionings are used to model periodic temporal notions, quite regular ones like years, months etc., partially regular ones like timetables, but also very irregular ones like, for example, dates of a conference series. These data structures can be used in the temporal specification language GeTS (GeoTemporal Specifications). GeTS is a functional specification and programming language with a number of builtin constructs for specifying customised temporal notions. CTTN is implemented as a Web server and as a C++ library. This paper gives a short overview over the current state of the system and its components. 1
Fuzzy Temporal Constraint Logic: A Valid Resolution Principle
, 2001
"... In this work we propose a fuzzy temporal constraint logic. First of all, we provide the formal language which will allow the expression of wellformed formulas related to the temporal events by means of temporal constraints. Secondly, we introduce a valid resolution principle in order to solve the q ..."
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Cited by 3 (0 self)
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In this work we propose a fuzzy temporal constraint logic. First of all, we provide the formal language which will allow the expression of wellformed formulas related to the temporal events by means of temporal constraints. Secondly, we introduce a valid resolution principle in order to solve the queries in this logic. Finally, we will show that this resolution principle is a generalization of the resolution principle proposed for a possibilistic logic with fuzzy predicates (Dubois and Prade, Internat. J. Approx. Reason. 4 (1990) 121). All this will serve to reason within a context of the theoretical model of the temporal reasoning proposed by Mar# #n and Barro (Fuzzy Temporal Constraint Network, FTCN) (Mar# #n et al., Cybernet. Systems 25(2) (1994) 207215). This model underlies a module for the resolution of temporal queries. This module belongs to a diagnostic and intelligent monitoring system of patients, based on temporal reasoning. The system is applied to the patients admitted in the Intensive Care Units with severe ischemic cardiopathy, submitted to continuous monitoring of the electrical and mechanical signals of the heart. However, what is exposed here in this document is not limited to a #eld of application in particular, but instead, it is completely general. c 2001 Elsevier Science B.V. All rights reserved.
A Fuzzy Temporal/Categorical Extension to the Parsimonious Covering Theory
 In The Seventh Conference on Information Processing and Management of Uncertainty in KnowledgeBased Systems (IPMU'98
, 1998
"... This paper proposes a way of incorporating fuzzy temporal reasoning within diagnostic reasoning. Disorders are described as an evolving set of necessary and possible manifestations. The expected duration of each manifestation and the interval of time expected to occur between the beginning of any tw ..."
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Cited by 2 (2 self)
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This paper proposes a way of incorporating fuzzy temporal reasoning within diagnostic reasoning. Disorders are described as an evolving set of necessary and possible manifestations. The expected duration of each manifestation and the interval of time expected to occur between the beginning of any two manifestations are modeled by fuzzy sets. The patient information about the beginning and duration of the manifestations is also described using fuzzy sets and different measures on how well a disorder explains the patient 's manifestations are defined. 1 Introduction Diagnostic problem solving has been an area of intense interest in Artificial Intelligence, and has generated many methodologies, theories and applications over the last two decades. Diagnostic systems vary from rulebased systems [2], setbased theories [12, 11], logic based theories [13, 9, 7], and casebased reasoning [8]. Furthermore, temporal reasoning within diagnosis has long been considered an important part of diagn...