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## Distributed Constraint Satisfaction Problems -- A Model and Application (1997)

Citations: | 4 - 1 self |

### Citations

1128 | Temporal constraint networks
- Dechter, Meiri, et al.
- 1991
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Citation Context ...tisfaction problems (CSPs) are problems that require the assignment of values to variables according to some constraints. Problems from many domains, such as computer vision and scheduling problems ((=-=Dechter, 1992-=-), (Haralick and Elliott, 1980)) can be represented as CSPs. We define in this paper a model for distributed constraint satisfaction problems (DCSPs), propose several algorithms for solving DCSPs, and... |

938 | Foundations of Constraint Satisfaction
- Tsang
- 1993
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Citation Context ...few attempts have been made to combine them into a unified framework. The processing of CSPs has been studied extensively in the last decade ((Dechter and Pearl, 1990), (Kumar, 1992),(Prosser, 1993),(=-=Tsang, 1993-=-), usually within the standard model that is sequential: assign values to variables, check constraints, backtrack if necessary. 4 a,b a,c b,b a,c a,a a,c c,a 1 1 1 3 1 2 X X X X 1 4 a,a a,b c,c a,a c,... |

521 |
Increasing tree search efficiency for constraint satisfaction problems
- Haralick, Elliott
- 1980
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Citation Context ...ms (CSPs) are problems that require the assignment of values to variables according to some constraints. Problems from many domains, such as computer vision and scheduling problems ((Dechter, 1992), (=-=Haralick and Elliott, 1980-=-)) can be represented as CSPs. We define in this paper a model for distributed constraint satisfaction problems (DCSPs), propose several algorithms for solving DCSPs, and test these algorithms both on... |

445 | Algorithms for constraint satisfaction problems: A survey
- Kumar
- 1992
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Citation Context ...digms are very powerful, only few attempts have been made to combine them into a unified framework. The processing of CSPs has been studied extensively in the last decade ((Dechter and Pearl, 1990), (=-=Kumar, 1992-=-),(Prosser, 1993),(Tsang, 1993), usually within the standard model that is sequential: assign values to variables, check constraints, backtrack if necessary. 4 a,b a,c b,b a,c a,a a,c c,a 1 1 1 3 1 2 ... |

407 | Network-based heuristics for constraint satisfaction problems - Dechter, Pearl - 1987 |

384 | Dynamic Backtracking
- Ginsberg
- 1993
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Citation Context ...ents may invest a lot of effort in finding an irrelevant solution, due to the failure of another agent. This disadvantage can be reduced if the agents use a method that learns from its failures (cf. (=-=Ginsberg, 1993-=-)). When an agent is looking for an alternative solution, it can be helped by knowledge that is acquired during search. It is easy to modify CFPA and PFCA (described in the next section) to be ExtAll ... |

379 | Hybrid algorithms for the constraint satisfaction problem
- Prosser
- 1993
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Citation Context ... powerful, only few attempts have been made to combine them into a unified framework. The processing of CSPs has been studied extensively in the last decade ((Dechter and Pearl, 1990), (Kumar, 1992),(=-=Prosser, 1993-=-),(Tsang, 1993), usually within the standard model that is sequential: assign values to variables, check constraints, backtrack if necessary. 4 a,b a,c b,b a,c a,a a,c c,a 1 1 1 3 1 2 X X X X 1 4 a,a ... |

280 | Enhancement schemes for constraint processing: Backjumping, learning, and cutset decomposition
- Dechter
- 1990
(Show Context)
Citation Context ...vertheless, in Section 5.1 we use this idea, and propose a limited form of computed expectations as an improvement to our basic algorithms. Some researchers, for example, Dechter & Collin (Collin and =-=Dechter, 1990-=-) or Kasif (Kasif, 1990). have proposed the Parallel way of solving CSP problems. It is important to emphasize that unlike (Collin and Dechter, 1990, Kasif, 1990) our goal is not using parallel proces... |

187 | Trends in cooperative distributed problem solving
- Lesser, Durfee, et al.
- 1989
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Citation Context ...ter checks involve some kind of message passing that the solving algorithm would like to minimize. The above situation leads naturally to a solution architecture which is based on Cooperative agents (=-=Durfee et al., 1989-=-) working individually on sub-problems of the problem. In our model, we assume that the agents are connected by a communication network (i.e., no common memory, just message passing). The number of ag... |

93 | On the Equivalence of Constraint Satisfaction Problems
- Rossi, Petrie, et al.
- 1990
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Citation Context ...alence will not permit addressing canonical and explicit representations of the same problem as equivalent since the canonical representation, as we will see, may have a greater number of nodes). In (=-=Rossi et al., 1990-=-) the equivalence between CSPs (called there the extended equivalence) was defined, for simplicity sake we will use a slightly more restrictive definition. A DCSP/CSP problem A is contained in a DCSP/... |

78 |
Binary constraint satisfaction problems: Some are harder than others
- Prosser
- 1994
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Citation Context ...erformed, and the number of messages sent, which are the two most important measures in such a distributed system. The "random" problem generation method, although very common in the CSP lit=-=erature ((Prosser, 1994-=-, Smith, 1994), does not always reflect reality. In particular, the assumption on the uniform difficulty of a component may not hold. Thus, the division of a DCSP problem to difficult and easy zones, ... |

57 | Dynamic Prioritization of Complex Agents in Distributed Constraint-Satisfaction Problems
- Armstrong, Durfee
- 1997
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Citation Context ...as a group of loosely coupled agents that need to find local solutions that together yield one or more solutions to a collective problem (Durfee et al., 1989, Luo et al., 1993). Armstrong and Durfee (=-=Armstrong and Durfee, 1997-=-) pointed out that a CDPS can be seen as a distributed CSP problem. The most relevant study of distributed CSPs has been made by Yokoo (Yokoo et al., 1990, Yokoo et al., 1992, Yokoo, 1995). A basic as... |

31 |
Resource allocation in distributed factory scheduling
- Sycara, Roth, et al.
- 1991
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Citation Context ...re, and the deep global knowledge needed by the agents in the high levels; make this approach impractical as a general approach to solve DCSPs. In the fields of scheduling and planing, Sycara et al. (=-=Sycara et al., 1991-=-) and (Durfee et al., 1989) built distributed systems. These systems did not use explicit CSP; however the problems solved by them can be easily mapped to CSPs. Their strategy was based on updating es... |

22 | N.: Experiments on Networks of Employee Timetabling Problems. Practice And Theory of Automated Timetabling II: Selected papers. Lecture
- Meisels, Lusternik
(Show Context)
Citation Context ...ving DCSPs, and test these algorithms both on a real life problem and on randomly generated problems. CSPs are often used to solve difficult Resource allocation (Prosser et al., 1992) or Timetabling (=-=Meisels and Lusternik, 1997-=-) problems. In many of these cases, the problem may be naturally partitioned into several components with constraints existing between parts of the components (e.g. the problem of scheduling courses f... |

20 |
A Reactive Scheduling Agent
- Prosser
- 1989
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Citation Context ...e. However in many real life problems such as the NTTT problem (see section 4) this is not the case. The algorithms proposed in this article were designed to overcome these problems. Prosser et. al. (=-=Prosser, 1989-=-, Prosser et al., 1992) built a hierarchical distributed system for job-shop scheduling whose lower level agents were CSP based, and its higher level agents included specific knowledge about the probl... |

19 |
Integer programming vs. expert systems: An experimental comparison
- Dhar, Ranganathan
- 1990
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Citation Context ... 100 1000 0 0.2 0.4 0.45 0.55 0.6 0.8 PFCA enhanced PFCA Figure 17. Messages for p 2 = 45 CSP. In particular, an agent may use techniques that are not constraint-based like Operation Research (e.g., (=-=Dhar and Ranganathan, 1990-=-),) or Knowledge Based methods (e.g., (Slagle and Hamburger, 1985),(Solotorevsky et al., 1994)), for solving its internal CSP. If the internal algorithms used by all the agents are sound and complete,... |

17 |
A constraint maintenance system for the distributed resource allocation problem
- Prosser, Conway, et al.
- 1992
(Show Context)
Citation Context ...s), propose several algorithms for solving DCSPs, and test these algorithms both on a real life problem and on randomly generated problems. CSPs are often used to solve difficult Resource allocation (=-=Prosser et al., 1992-=-) or Timetabling (Meisels and Lusternik, 1997) problems. In many of these cases, the problem may be naturally partitioned into several components with constraints existing between parts of the compone... |

14 | Agent-Based Cooperative Scheduling
- Murthy, Akkiraju, et al.
- 1997
(Show Context)
Citation Context ... whole problem. This differs from the approach used by some multi-agent systems, in which each agent has a global view of the problem which is used for achieving optimal solutions of the CSP problem (=-=Murthy et al., 1997-=-, Anke et al., 1997). 2. A Model for DCSPs Constraint satisfaction problems require the assignments of values to variables according to some constraints. A CSP is composed of a set of variables X 1 ; ... |

12 | Heuristic Search for Distributed Constraint Satisfaction Problems
- Luo, Hendry, et al.
- 1993
(Show Context)
Citation Context ...2. An explicit DCSP 5 CDPS is often seen as a group of loosely coupled agents that need to find local solutions that together yield one or more solutions to a collective problem (Durfee et al., 1989, =-=Luo et al., 1993-=-). Armstrong and Durfee (Armstrong and Durfee, 1997) pointed out that a CDPS can be seen as a distributed CSP problem. The most relevant study of distributed CSPs has been made by Yokoo (Yokoo et al.,... |

12 |
An Expert System for a Resource Allocation Problem
- Slagle, Hamburger
- 1985
(Show Context)
Citation Context ...7. Messages for p 2 = 45 CSP. In particular, an agent may use techniques that are not constraint-based like Operation Research (e.g., (Dhar and Ranganathan, 1990),) or Knowledge Based methods (e.g., (=-=Slagle and Hamburger, 1985-=-),(Solotorevsky et al., 1994)), for solving its internal CSP. If the internal algorithms used by all the agents are sound and complete, then all the algorithms presented in this paper have the same pr... |

10 |
RAPS: A rule-based language specifying resource allocation and time-tabling problems
- Solotorevsky, Gudes, et al.
- 1994
(Show Context)
Citation Context ... In particular, an agent may use techniques that are not constraint-based like Operation Research (e.g., (Dhar and Ranganathan, 1990),) or Knowledge Based methods (e.g., (Slagle and Hamburger, 1985),(=-=Solotorevsky et al., 1994-=-)), for solving its internal CSP. If the internal algorithms used by all the agents are sound and complete, then all the algorithms presented in this paper have the same property. The experimental res... |

9 |
Phase Transition and the Mushy Region in CSP
- Smith
- 1994
(Show Context)
Citation Context ...he number of messages sent, which are the two most important measures in such a distributed system. The "random" problem generation method, although very common in the CSP literature ((Pross=-=er, 1994, Smith, 1994-=-), does not always reflect reality. In particular, the assumption on the uniform difficulty of a component may not hold. Thus, the division of a DCSP problem to difficult and easy zones, does not alwa... |

8 |
A distributed solution to the network consistency problem. Methodoiog. ics for Intelligent Systems
- Collin, Dechter
- 1990
(Show Context)
Citation Context ...tations. Nevertheless, in Section 5.1 we use this idea, and propose a limited form of computed expectations as an improvement to our basic algorithms. Some researchers, for example, Dechter & Collin (=-=Collin and Dechter, 1990-=-) or Kasif (Kasif, 1990). have proposed the Parallel way of solving CSP problems. It is important to emphasize that unlike (Collin and Dechter, 1990, Kasif, 1990) our goal is not using parallel proces... |

7 | A cooperative repair method for a distributed scheduling system
- Neiman, Lesser
- 1996
(Show Context)
Citation Context ...hm PFCA is applied as usual (without using value ordering heuristics). A difference between our approach and approaches based on estimations suggested in the field of scheduling (Sycara et al., 1991, =-=Neiman and Lesser, 1996-=-) is that our method is based on a priori estimations that aren't updated during the solution process. The reason for this is that in the context of CSPs partial assignments change very often, much of... |

5 | Bayes Networks for estimating the number of solutions to a CSP
- Meisels, Shimony, et al.
(Show Context)
Citation Context ...nment of values to some (or all) of its nodes that participate in external constraints. Such a method was first suggested by Pearl and Dechter in (Dechter and Pearl, 1990), and later improved by us ((=-=Meisels et al., 1997-=-),(Solotorevsky et al., 1998)). Our method is based on representing the CSP as a Bayes network and then calculating approximations to the value of the network (this calculation requires a low polynomi... |

3 | Producing and Improving Time Tables by Means of Constraint and Multiagent Systems
- Anke, Staudte, et al.
- 1997
(Show Context)
Citation Context ...differs from the approach used by some multi-agent systems, in which each agent has a global view of the problem which is used for achieving optimal solutions of the CSP problem (Murthy et al., 1997, =-=Anke et al., 1997-=-). 2. A Model for DCSPs Constraint satisfaction problems require the assignments of values to variables according to some constraints. A CSP is composed of a set of variables X 1 ; X 2 ; :::; Xn with ... |

2 | Distributed Medical Evacuation Planning: What Problem Should Each Agent Solve
- Saks, Braidic, et al.
- 1997
(Show Context)
Citation Context ...rses for multiple departments in the same university). A strong requirement in such cases is that local autonomy and control requires the preserving of the natural partition of the problem (see e.g. (=-=Saks et al., 1997-=-)). The existence of such problems motivates the model and application in this paper. 2 The real life problem that is presented and solved in this paper is the problem of constructing a weekly time-ta... |

1 |
From Evaluating Upper Bounds of the Complexity of Solving CSPs to finding All the Solutions of CSPs
- Solotorevsky
- 1996
(Show Context)
Citation Context ...thms is the backtracking order. Since to guarantee completeness this order is fixed, its initial determination is important. In theory we may use estimations on the complexity of the CSP subproblems (=-=Solotorevsky, 1996-=-) as an indication, however in practice because of CPU and communication in-balances, this order is determined at run-time as the algorithm proceeds (last to arrive last to backtrack). In terms of Per... |

1 | Distributed constraint satisfaction for dai problems - al - 1990 |