Extending Fuzzy Constraint Satisfaction Problems

Author(s):  
Yasuhiro Sudo ◽  
◽  
Masahito Kurihara ◽  
Tamotsu Mitamura ◽  
◽  
...  

This paper propose a new type of Fuzzy CSP (Constraint Satisfaction Problem) that have a mixture of discrete and continuous domains, and a Spread-Repair algorithm. In traditional CSP and Fuzzy CSP, values for the variables are chosen from the discrete domains. However, this is often inconvenient when one wants to express real world problems. We show that this model, called HDFCSP (Hybrid Domain Fuzzy CSP), can be solved by Spread-Repair, an extension of the well known iterative improvement algorithms. Experimental results on some test problems show that the algorithm actually has an ability of finding partial approximate solutions with high probability in a computation time much shorter than the traditional, discrete-domain FCSP.

Author(s):  
Vicenç Torra I Reventós

Several real-world applications (e.g., scheduling, configuration, …) can be formulated as Constraint Satisfaction Problems (CSP). In these cases, a set of variables have to be settled to a value with the requirement that they satisfy a set of constraints. Classical CSPs are defined only by means of crisp (Boolean) constraints. However, as sometimes Boolean constraints are too strict in relation to human reasoning, fuzzy constraints were introduced. When fuzzy constraints are considered, human reasoning usually performs some compensation between alternatives. Thus other operators than t-norms are advisable. Besides of that, not all constraints can be considered with equal importance. In this paper we show that the WOWA operator can consider both aspects: compensation between constraints and constraints of different importance.


Author(s):  
Takuto Yanagida ◽  
◽  
Masahito Kurihara ◽  
Hidetoshi Nonaka

This paper presents a software tool to intuitively comprehend and analyze fuzzy constraint satisfaction problems (FCSPs) through effective visualization with animation. FCSPs are an extension of constraint satisfaction problems (CSPs), which are used for formulating problems in real-world information systems. Once we formulate a problem as an FCSP, it can be solved (in principle) by any existing general-purpose FCSP solvers developed so far. However, the formulation is sometimes difficult because it requires high abstraction of real-world problems and affects the performance of the solvers. The authors believe that the tool will improve this situation by increasing the visibility of the behavior of the solvers.


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