1,721,019 research outputs found
Spatial Reasoning with Integrated Qualitative-Metric Fuzzy Constraint Network
No full textQualitative Spatial Reasoning can be greatly improved if metric information can be represented and reasoning can be performed on it; moreover, modelling vagueness and uncertainty in both qualitative and metric relations allows reasoning in a more flexible way about data coming from real world. In this paper Rectangle Algebra is integrated with a bi-dimensional Point Algebra by defining a set of 25 Point-Region relations, in this way a Spatial Qualitative Algebra (SQA) among point and regions is obtained. Besides, SQA is extended to deal with uncertain data by means of the Fuzzy Sets Theory. Fuzzy metric information is represented using pyramidal possibility distributions, and transformation functions that allow passing from qualitative to metric information and vice versa are provided
Fuzzy Disjunctive Temporal Problem with Classes
No full textThis paper describes a framework for temporal reasoning that allows managing a restricted form of disjunctive temporal constraints without making the modelled problems intractable as in the case of general DTPs. This is obtained by assigning classes to the constraints and by allowing only one constraint per class, in order to build a collection of independent STPs that can share sub-problems and therefore allows increasing algorithm efficiency. The model proposed is directly applied to Fuzzy Constraint Satisfaction Problems and can be solved using an extended Fuzzy Path-Consistency algorithm, also presented in the paper. A simple application to medical diagnosis shows its expressive power over previous tractable temporal reasoning models
Applying a Fuzzy Temporal Constraint System to medical diagnoses
No full textIn this paper we present the application of a Fuzzy Temporal Constraint System we have developed to the case of Severe Acute Respiratory Syndrome (SARS). The idea is to schedule the temporal evolutions of symptoms which characterize this ill-known disease by modelling them in a Temporal Constraint Network and then to check their consistency w.r.t patients’ data. In particular, we show how handling both fuzzy qualitative and metric constraints allows us to represent in a flexible way the symptoms in different patients thus making possible to deduce characteristic periods of an unknown disease such as SARS was. A new user interface is proposed for the system
About Tractability of Fuzzy Temporal Qualitative Algebra QAfuz
No full textIn this paper, we study the tractability of the Fuzzy Temporal Qualitative Algebra QAf uz . To this aim, we extend to the fuzzy framework the study presented in [7] where all tractable fragments of the Qualitative Algebra are identified. We don’t directly extend classical proofs to our fuzzy framework, but we generalize the results obtained in the classical case exploiting the notion of α-cut in relating the QAfuz to its classical counterpart QA
Temporal-based medical diagnoses using a Fuzzy Temporal Constraint System
Full text linkWe apply the Fuzzy Temporal Constraint System we have developed to the case of SARS (Severe Acute Respiratory Syndrome). The idea is to characterize the temporal evolution of the symptoms of this ill-known disease by modelling patients' data in a Fuzzy Temporal Constraint Network. We discuss how the system is able to manage both fuzzy qualitative and metric constraints allowing to represent in a flexible manner
the symptoms of different patients. In this way it is possible to
deduce characteristic periods of an ill-known disease such as SARS
was. A new user interface is included into the architecture of the
System
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