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Idwalk : A candidate list strategy with a simple diversification device
- CP 2004: Lecture Notes in Computer Science
, 2004
"... Abstract. This paper presents a new optimization metaheuristic called ID Walk (Intensification/Diversification Walk) that offers advantages for combining simplicity with effectiveness. In addition to the number S of moves, ID Walk uses only one parameter Max which is the maximum number of candidate ..."
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Cited by 9 (4 self)
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Abstract. This paper presents a new optimization metaheuristic called ID Walk (Intensification/Diversification Walk) that offers advantages for combining simplicity with effectiveness. In addition to the number S of moves, ID Walk uses only one parameter Max which is the maximum number of candidate neighbors studied in every move. This candidate list strategy manages the Max candidates so as to obtain a good tradeoff between intensification and diversification. A procedure has also been designed to tune the parameters automatically. We made experiments on several hard combinatorial optimization problems, and ID Walk compares favorably with correspondingly simple instances of leading metaheuristics, notably tabu search, simulated annealing and Metropolis. Thus, among algorithmic variants that are designed to be easy to program and implement, ID Walk has the potential to become an interesting alternative to such recognized approaches. Our automatic tuning tool has also allowed us to compare several variants of ID Walk and tabu search to analyze which devices (parameters) have the greatest impact on the computation time. A surprising result shows that the specific diversification mechanism embedded in ID Walk is very significant, which motivates examination of additional instances in this new class of “dynamic ” candidate list strategies. 1
Algorithms for the Radio Link Frequency Assignment Problem
, 1999
"... The radio link frequency assignment problem occurs when a network of radio links has to be established. Each link must be assigned an operating frequency from a given domain. The assignment has to satisfy certain restrictions so as to limit the interference between links. The number of frequencie ..."
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The radio link frequency assignment problem occurs when a network of radio links has to be established. Each link must be assigned an operating frequency from a given domain. The assignment has to satisfy certain restrictions so as to limit the interference between links. The number of frequencies used is to be minimized. Problems of this type were investigated by a consortium consisting of research groups from Delft, Eindhoven, London, Maastricht, Norwich, and Toulouse. The participants developed optimization algorithms based on branch-and-cut and constraint satisfaction, and approximation techniques including a variety of local search methods, genetic algorithms, neural networks, and potential reduction. These algorithms were tested and compared on a set of real-life instances.
Lower bounds for Minimum Interference Frequency Assignment Problems
, 1999
"... In this paper we describe a new lower bound procedure for the minimum interference frequency assignment problem (MI-FAP). In the MI-FAP we have to assign frequencies to transmitter-receiver pairs in suchaway that the cumulativeinterference in the communication network is minimized. Mainly due to the ..."
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Cited by 7 (2 self)
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In this paper we describe a new lower bound procedure for the minimum interference frequency assignment problem (MI-FAP). In the MI-FAP we have to assign frequencies to transmitter-receiver pairs in suchaway that the cumulativeinterference in the communication network is minimized. Mainly due to the fairly large number of available frequencies, exact methods fail to solve the more difficult instances. In this paper we describe a procedure that produces a non-decreasing sequence of lower bounds. In each iteration of the algorithm we have to solve MI-FAPs that are substantially smaller than the original instance. These subproblems can be solved with either integer programming techniques or a dynamic programming algorithm based on a tree decomposition of the underlying graph. Computational results show that integer programming and dynamic programming supply very good results.
Frequency planning and ramification of coloring
, 2002
"... This paper surveys frequency assignment problems coming up in planning wireless communication services. It particularly focuses on cellular mobile phone systems such as GSM, a technology that revo lutionizes communication. Traditional vertex coloring provides a con ceptual framework for the mathemat ..."
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Cited by 4 (0 self)
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This paper surveys frequency assignment problems coming up in planning wireless communication services. It particularly focuses on cellular mobile phone systems such as GSM, a technology that revo lutionizes communication. Traditional vertex coloring provides a con ceptual framework for the mathematical modeling of many frequency planning problems. This basic form, however, needs various exten sions to cover technical and organizational side constraints. Among these ramifications are T-coloring and list coloring. To model all the subtleties, the techniques of integer programming have proven to be very useful. The ability to produce good frequency plans in practice is essential for the quality of mobile phone networks. The present algorithmic solution methods employ variants of some of the traditional coloring heuristics as well as more sophisticated machinery from mathematical programming. This paper will also address this issue. Finally, this paper discusses several practical frequency assignment problems in detail, states the associated mathematical models, and also points to public electronic libraries of frequency assignment problems from practice. The associated graphs have up to several thousand vertices and range form rather sparse to almost complete.
Models and methods for frequency allocation with cumulative interference constraints
"... We consider a realistic modelling of interferences for frequency allocation in hertzian telecommunication networks. In contrast with traditional interference models based only on binary interference constraints, this new approach considers the case of a receiver disrupted simultaneously by several ..."
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Cited by 3 (2 self)
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We consider a realistic modelling of interferences for frequency allocation in hertzian telecommunication networks. In contrast with traditional interference models based only on binary interference constraints, this new approach considers the case of a receiver disrupted simultaneously by several senders yielding cumulative disruptions that are modelled through a unique non-binary constraint. To deal with these complex constraints, we propose extensions of classical integer linear programming formulations. On a set of realistic instances provided by the CELAR, we propose several exact and heuristic solution methods including branch and cut, constraint programming, and large neighbourhood search. We also compare the performances of our best methods with those of existing heuristics and we show how the end-user benefits from using the cumulative model instead of the traditional one.
Models and methods for frequency assignment with cumulative interference constraints
"... Abstract: In this paper, a realistic modeling of interferences for frequency assignment in hertzian telecom-munication networks is presented. In contrast with traditional interference models based only on binary interference constraints involving two frequencies, this new approach considers the case ..."
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Abstract: In this paper, a realistic modeling of interferences for frequency assignment in hertzian telecom-munication networks is presented. In contrast with traditional interference models based only on binary interference constraints involving two frequencies, this new approach considers the case of cumulative disruptions that are modeled through a unique non-binary constraint. To deal with these complex constraints, we propose extensions of classical integer linear programming formulations. On a set of realistic instances, we propose hybrid constraint programming and large neighborhood search solution methods to solve minimum interference and minimum span frequency assignment problems. We compare their performances with those of existing heuristics. Finally, we show how the end-user benefits from using the cumulative model instead of the traditional one.
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"... Domination analysis of greedy heuristics for the frequency assignment problem A.E. Koller∗ † and S.D. Noble† We introduce the greedy expectation algorithm for the fixed spectrum version of the frequency assignment problem. This algorithm was previously studied for the travelling salesman problem. We ..."
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Domination analysis of greedy heuristics for the frequency assignment problem A.E. Koller∗ † and S.D. Noble† We introduce the greedy expectation algorithm for the fixed spectrum version of the frequency assignment problem. This algorithm was previously studied for the travelling salesman problem. We show that the domination number of this algorithm is at least σn−⌈log2 n⌉−1 where σ is the available span and n the number of vertices in the constraint graph. In contrast to this we show that the standard greedy algorithm has domination number strictly less than σne− 5(n−1) 144 for large n and fixed σ.
