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539
Approximating the SingleSink Link Installation Problem in Network Design
, 1998
"... We initiate the algorithmic study of an important but NPhard problem that arises commonly in network design. The input consists of (1) An undirected graph with one sink node and multiple source nodes, a specified length for each edge, and a specified demand, dem v , for each source node v. (2) ..."
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Cited by 42 (2 self)
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We initiate the algorithmic study of an important but NPhard problem that arises commonly in network design. The input consists of (1) An undirected graph with one sink node and multiple source nodes, a specified length for each edge, and a specified demand, dem v , for each source node v. (2) A small set of cable types, where each cable type is specified by its capacity and its cost per unit length. The cost per unit capacity per unit length of a highcapacity cable may be significantly less than that of a lowcapacity cable, reflecting an economy of scale, i.e., the payoff for buying at bulk may be very high. The goal is to design a minimumcost network that can (simultaneously) route all the demands at the sources to the sink, by installing zero or more copies of each cable type on each edge of the graph. An additional restriction is that the demand of each source must follow a single path. The problem is to find a route from each source node to the sink and to assign ca...
Complexity of scheduling multiprocessor tasks with prespecified processor allocations
 DISCRETE APPLIED MATHEMATICS
, 1994
"... ..."
An Evolutionary Approach to Combinatorial Optimization Problems
 PROCEEDINGS OF THE 22ND ANNUAL ACM COMPUTER SCIENCE CONFERENCE
, 1994
"... The paper reports on the application of genetic algorithms, probabilistic search algorithms based on the model of organic evolution, to NPcomplete combinatorial optimization problems. In particular, the subset sum, maximum cut, and minimum tardy task problems are considered. Except for the fitness ..."
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Cited by 40 (5 self)
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The paper reports on the application of genetic algorithms, probabilistic search algorithms based on the model of organic evolution, to NPcomplete combinatorial optimization problems. In particular, the subset sum, maximum cut, and minimum tardy task problems are considered. Except for the fitness function, no problemspecific changes of the genetic algorithm are required in order to achieve results of high quality even for the problem instances of size 100 used in the paper. For constrained problems, such as the subset sum and the minimum tardy task, the constraints are taken into account by incorporating a graded penalty term into the fitness function. Even for large instances of these highly multimodal optimization problems, an iterated application of the genetic algorithm is observed to find the global optimum within a number of runs. As the genetic algorithm samples only a tiny fraction of the search space, these results are quite encouraging.
Planning UMTS Base Station Location: Optimization Models with Power Control and Algorithms
 IEEE Transactions on Wireless Communications
, 2003
"... Classical coverage models, adopted for secondgeneration cellular systems, are not suited for planning universal mobile telecommunication system (UMTS) base station (BS) location because they are only based on signal predictions and do not consider the traffic distribution, the signal quality requir ..."
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Cited by 38 (7 self)
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Classical coverage models, adopted for secondgeneration cellular systems, are not suited for planning universal mobile telecommunication system (UMTS) base station (BS) location because they are only based on signal predictions and do not consider the traffic distribution, the signal quality requirements, and the power control (PC) mechanism. In this paper, we propose discrete optimization models and algorithms aimed at supporting the decisions in the process of planning where to locate new BSs. These models consider the signaltointerference ratio as quality measure and capture at different levels of detail the signal quality requirements and the specific PC mechanism of the wideband CDMA air interface. Given that these UMTS BS location models are nonpolynomial (NP)hard, we propose two randomized greedy procedures and a tabu search algorithm for the uplink (mobile to BS) direction which is the most stringent one from the traffic point of view in the presence of balanced connections such as voice calls. The different models, which take into account installation costs, signal quality and traffic coverage, and the corresponding algorithms, are compared on families of small to largesize instances generated by using classical propagation models.
A Dynamic Programming Approach for Consistency and Propagation for Knapsack Constraints
 Annals of Operations Research
, 2001
"... Knapsack constraints are a key modeling structure in constraint programming. These constraints are normally handled with simple bounding arguments. We propose a dynamic programming structure to represent these constraints. With this structure, we show how to achieve hyperarc consistency, to determi ..."
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Cited by 38 (0 self)
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Knapsack constraints are a key modeling structure in constraint programming. These constraints are normally handled with simple bounding arguments. We propose a dynamic programming structure to represent these constraints. With this structure, we show how to achieve hyperarc consistency, to determine infeasibility before all variables are set, to generate all solutions quickly, and to update the structure after domain reduction. Preliminary testing on a dicult set of multiple knapsack instances shows signicant reduction in branching, though an eective implementation is needed in order to reduce computation time. Keywords: Global Constraints, Dynamic Programming, Knapsack Constraints 1.
A Polyhedral Approach to Multicommodity Survivable Network Design
 Numerische Mathematik
, 1993
"... The design of costefficient networks satisfying certain survivability ..."
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Cited by 36 (0 self)
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The design of costefficient networks satisfying certain survivability
An Approach for Quality of Service Management
, 1998
"... We present a translucent QoS management optimization framework for systems that must satisfy application needs along multiple dimensions such as timeliness, reliability, cryptographic security and other applicationspecific quality requirements. The architecture of the system consists of a semantica ..."
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Cited by 35 (1 self)
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We present a translucent QoS management optimization framework for systems that must satisfy application needs along multiple dimensions such as timeliness, reliability, cryptographic security and other applicationspecific quality requirements. The architecture of the system consists of a semantically rich (in terms of customizable and expressiveness) QoS specification interface for multidimensional QoS provisioning, a qualityofservice index model to help the user make the quality tradeo# decision, and a unified QoSbased admission control and resource planning system.The semantically rich QoS specification interface allows the user or system administrator to define finegrained service requests in terms of quality or rate of service. The QoS index model is designed to be flexible and policy driven. The unified QoSbased admission and resource control facilitates the deployment of various QoS policies to meet performance objectives for specific service optimizations. Finally, the ov...
PeertoPeer Data Trading to Preserve Information
 ACM Transactions on Information Systems
"... Data archiving systems rely on replication to preserve information. This paper discusses how a network of autonomousarchiving sites can trade data to achieve the most reliable replication. A series of binary trades among sites produces a peertopeer archiving network. Two trading algorithms are e ..."
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Cited by 35 (8 self)
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Data archiving systems rely on replication to preserve information. This paper discusses how a network of autonomousarchiving sites can trade data to achieve the most reliable replication. A series of binary trades among sites produces a peertopeer archiving network. Two trading algorithms are examined, one based on trading collections (even if they are different sizes) and another based on trading equal sized blocks of space (which can then store collections.) The concept of deeds is introduced; deeds track the blocks of space owned by one site at another. Policies for tuning these algorithms to provide the highest reliability, for example by changing the order in which sites are contacted and offered trades, are discussed. Finally, simulation results are presented that reveal which policies are best. The experiments indicate that a digital archive can achieve the best reliability by trading blocks of space (deeds), and that following certain policies will allow that site to maximize its reliability. Categories and Subject Descriptors: H.3.7 [Information storage and retrieval]: Digital libraries  systems issues; E.5 [Files]: Backup/recovery General Terms: Design, reliability Additional Key Words and Phrases: data replication, fault tolerance, digital archiving, digital library, resource negotiation 1
The ThreeDimensional Bin Packing Problem
 Operations Research
, 2000
"... The problem addressed in this paper is that of orthogonally packing a given set of rectangularshaped boxes into the minimum number of rectangular bins. The problem is strongly NPhard and extremely difficult to solve in practice. Lower bounds are discussed, and it is proved that the asymptotical wo ..."
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Cited by 34 (3 self)
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The problem addressed in this paper is that of orthogonally packing a given set of rectangularshaped boxes into the minimum number of rectangular bins. The problem is strongly NPhard and extremely difficult to solve in practice. Lower bounds are discussed, and it is proved that the asymptotical worstcase performance of the continuous lower bound is 1/8. An exact algorithm for filling a single bin is developed, leading to the definition of a exact branchandbound algorithm for the threedimensional bin packing problem, which also incorporates original approximation algorithms. Extensive computational results, involving instances with up to 60 boxes, are presented: it is shown that many instances can be solved to optimality within a reasonable time limit.
A Cutting Plane Algorithm for Multicommodity Survivable Network Design Problems
, 1995
"... Wepresentacuttingplanealgorithm forsolving thefollowingnetworkdesignproblemintelecommunications: given pointtopointtraffic demandsinanetwork,specified survivabilityrequirementsanda discretecost/capacityfunctionforeachlink, find minimumcostcapacityexpansionssatisfyingthegiven demands. The algori ..."
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Cited by 33 (0 self)
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Wepresentacuttingplanealgorithm forsolving thefollowingnetworkdesignproblemintelecommunications: given pointtopointtraffic demandsinanetwork,specified survivabilityrequirementsanda discretecost/capacityfunctionforeachlink, find minimumcostcapacityexpansionssatisfyingthegiven demands. The algorithm is based onthe polyhedralstudyintheaccompanying paper [16]. We describe the underlying problem,the model and the main ingredients in our algorithm: initial formulation,feasibility test, separation for strong cutting planes and primal heuristics. Computational results for a set of realworld problems are reported.