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380
Capacity of MultiChannel Wireless Networks with Random (c, f) Assignment
, 2007
"... With the availability of multiple unlicensed spectral bands, and potential costbased limitations on the capabilities of individual nodes, it is increasingly relevant to study the performance of multichannel wireless networks with channel switching constraints. To this effect, some constraint models ..."
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Cited by 243 (11 self)
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With the availability of multiple unlicensed spectral bands, and potential costbased limitations on the capabilities of individual nodes, it is increasingly relevant to study the performance of multichannel wireless networks with channel switching constraints. To this effect, some constraint models have been recently proposed, and connectivity and capacity results have been formulated for networks of randomly deployed singleinterface nodes subject to these constraints. One of these constraint models is termed random (c, f) assignment, wherein each node is preassigned a random subset of f channels out of c (each having bandwidth W c), and may only switch on these. Previous results for this model established bounds on network capacity, and proved that when c = O(logn), the perprnd f flow capacity is O(W nlogn) and Ω(W cnlogn) (where prnd = 1 −(1 − f f f f 2 c)(1 − c−1)...(1 − c − f+1) ≥ 1 − e − c). In this paper we present a lower bound construction that matches the previous upper prnd bound. This establishes the capacity as Θ(W nlogn). The surprising implication of this result is that when f = Ω ( √ c), random (c, f) assignment yields capacity of the same order as attainable via unconstrained switching. The routing/scheduling procedure used by us to achieve capacity requires synchronized routeconstruction for all flows in the network, leading to the open question of whether it is possible to achieve capacity using asynchronous procedures.
Efficient Routing and Scheduling Algorithms for Optical Networks
"... This paper studies the problems of dedicating routes and scheduling transmissions in optical networks. In optical networks, the vast bandwidth available in an optical fiber is utilized by partitioning it into several channels, each at a different optical wavelength. A connection between two nodes is ..."
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Cited by 79 (4 self)
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This paper studies the problems of dedicating routes and scheduling transmissions in optical networks. In optical networks, the vast bandwidth available in an optical fiber is utilized by partitioning it into several channels, each at a different optical wavelength. A connection between two nodes is assigned a specific wavelength, with the constraint that no two connections sharing a link in the network can be assigned the same wavelength. This paper classifies several models related to optical networks and presents optimal or nearoptimal algorithms for permutation routing and/or scheduling problems in many of these models. some scheduling problems in one specific model.
Computing on anonymous networks, part I: characterizing the solvable cases
 IEEE TRANSACTION ON PARALLEL AND DISTRIBUTED COMPUTING
, 1996
"... In anonymous networks, the processors do not have identity numbers. We investigate the following representative problems on anonymous networks: (a) the leader election problem, (b) the edge election problem, (c) the spanning tree construction problem, and (d) the topology recognition problem. On a g ..."
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Cited by 74 (3 self)
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In anonymous networks, the processors do not have identity numbers. We investigate the following representative problems on anonymous networks: (a) the leader election problem, (b) the edge election problem, (c) the spanning tree construction problem, and (d) the topology recognition problem. On a given network, the above problems may or may not be solvable, depending on the amount of information about the attributes of the network made available to the processors. Some possibilities are: (1) no network attribute information at all is available, (2) an upper bound on the number of processors in the network is available, (3) the exact number of processors in the network is available, and (4) the topology of the network is available. In terms of a new graph property called “symmetricity, ” in each of the four cases (1)–(4) above, we characterize the class of networks on which each of the four problems (a)–(d) is solvable. We then relate the symmetricity of a network to its 1 and 2factors.
Linear Assignment Problems and Extensions
"... This paper aims at describing the state of the art on linear assignment problems (LAPs). Besides sum LAPs it discusses also problems with other objective functions like the bottleneck LAP, the lexicographic LAP, and the more general algebraic LAP. We consider different aspects of assignment problems ..."
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Cited by 54 (0 self)
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This paper aims at describing the state of the art on linear assignment problems (LAPs). Besides sum LAPs it discusses also problems with other objective functions like the bottleneck LAP, the lexicographic LAP, and the more general algebraic LAP. We consider different aspects of assignment problems, starting with the assignment polytope and the relationship between assignment and matching problems, and focusing then on deterministic and randomized algorithms, parallel approaches, and the asymptotic behaviour. Further, we describe different applications of assignment problems, ranging from the well know personnel assignment or assignment of jobs to parallel machines, to less known applications, e.g. tracking of moving objects in the space. Finally, planar and axial threedimensional assignment problems are considered, and polyhedral results, as well as algorithms for these problems or their special cases are discussed. The paper will appear in the Handbook of Combinatorial Optimization to be published
Beyond the Glass Box: Constraints as Objects
, 1995
"... Constraint Logic Programming (CLP) is a very active research area. One reason being that finite domain CLP systems have been successfully applied to various combinatorial optimization problems such as time tabling, scheduling, frequency allocation, manpower planning, production planning. State of th ..."
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Cited by 50 (2 self)
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Constraint Logic Programming (CLP) is a very active research area. One reason being that finite domain CLP systems have been successfully applied to various combinatorial optimization problems such as time tabling, scheduling, frequency allocation, manpower planning, production planning. State of the art finite domain CLP languages offer programming constructs that gives access to the state of the constraint solver. With these constructs, new constraints can be defined in the CLP language directly, hence the name "glassbox". However, current glass box approaches do not give access to the constraints themselves. This prevents the use of sophisticated constraint solving techniques borrowed from Operations Research. In order to overcome this limitation, we propose to give acces to the constraints as first class citizen of the CLP language. We implemented this approach into an object oriented language, where constraints are explicitly represented by objects. We provide both theoretical and experimental evidence of the interest of our approach. In particular, we show that some of our extensions provide speedups of more than one order of magnitude over current glass box constraint solvers.
Advanced Algorithms for Fast and Scalable Deep Packet Inspection
, 2006
"... Modern deep packet inspection systems use regular expressions to define various patterns of interest in network data streams. Deterministic Finite Automata (DFA) are commonly used to parse regular expressions. DFAs are fast, but can require prohibitively large amounts of memory for patterns arising ..."
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Cited by 44 (1 self)
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Modern deep packet inspection systems use regular expressions to define various patterns of interest in network data streams. Deterministic Finite Automata (DFA) are commonly used to parse regular expressions. DFAs are fast, but can require prohibitively large amounts of memory for patterns arising in network applications. Traditional DFA table compression only slightly reduces the memory required and requires an additional memory access per input character. Alternative representations of regular expressions, such as NFAs and Delayed Input DFAs (D 2 FA) require less memory but sacrifice throughput. In this paper we introduce the Content Addressed Delayed Input DFA (CD 2 FA), which provides a compact representation of regular expressions that match the throughput of traditional uncompressed DFAs. A CD 2 FA addresses successive states of a D 2 FA using their content, rather than a “contentless ” identifier. This makes selected information available earlier in the state traversal process, which makes it possible to avoid unnecessary memory accesses. We demonstrate that such contentaddressing can be effectively used to obtain automata that are very compact and can achieve high throughput. Specifically, we show that for an application using thousands of patterns defined by regular expressions, CD 2 FAs use as little as 10 % of the space required by a conventional compressed DFA, and match the throughput of an uncompressed DFA.
The alldifferent Constraint: A Survey
, 2001
"... The constraint of difference is known to the constraint programming community since Lauriere introduced Alice in 1978. Since then, several strategies have been designed to solve the alldifferent constraint. This paper surveys the most important developments over the years regarding the alldifferent ..."
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Cited by 43 (1 self)
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The constraint of difference is known to the constraint programming community since Lauriere introduced Alice in 1978. Since then, several strategies have been designed to solve the alldifferent constraint. This paper surveys the most important developments over the years regarding the alldifferent constraint. First we summarize the underlying concepts and results from graph theory and integer programming. Then we give an overview and an abstract comparison of different solution strategies. In addition, the symmetric alldifferent constraint is treated. Finally, we show how to apply costbased filtering to the alldifferent constraint.
A simple algorithm for finding maximal network flows and an application to the Hitchcock problem
 CANADIAN JOURNAL OF MATHEMATICS
, 1957
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Probabilistic data exchange
 In Proc. ICDT
, 2010
"... The work reported here lays the foundations of data exchange in the presence of probabilistic data. This requires rethinking the very basic concepts of traditional data exchange, such as solution, universal solution, and the certain answers of target queries. We develop a framework for data exchange ..."
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Cited by 41 (6 self)
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The work reported here lays the foundations of data exchange in the presence of probabilistic data. This requires rethinking the very basic concepts of traditional data exchange, such as solution, universal solution, and the certain answers of target queries. We develop a framework for data exchange over probabilistic databases, and make a case for its coherence and robustness. This framework applies to arbitrary schema mappings, and finite or countably infinite probability spaces on the source and target instances. After establishing this framework and formulating the key concepts, we study the application of the framework to a concrete and practical setting where probabilistic databases are compactly encoded by means of annotations formulated over random Boolean variables. In this setting, we study the problems of testing for the existence of solutions and universal solutions, materializing such solutions, and evaluating target queries (for unions of conjunctive queries) in both the exact sense and the approximate sense. For each of the problems, we carry out a complexity analysis based on properties of the annotation, in various classes of dependencies. Finally, we show that the framework and results easily and completely generalize to allow not only the data, but also the schema mapping itself to be probabilistic.