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Results 1 - 10
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202
Using global constraints for rectangle packing
- In Proceedings of the first Workshop on Bin Packing and Placement Constraints BPPC’08
, 2008
"... Abstract. In this paper we solve the optimal rectangle packing problem using Cumulative and Disjoint2 constraints in SICStus Prolog with a novel decomposition method, together with a specialized search routine and various model enhancements. We improve the best known runtimes by up to a factor of 30 ..."
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Cited by 4 (0 self)
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Abstract. In this paper we solve the optimal rectangle packing problem using Cumulative and Disjoint2 constraints in SICStus Prolog with a novel decomposition method, together with a specialized search routine and various model enhancements. We improve the best known runtimes by up to a factor
On the Combination of Symbolic Constraints, Solution Domains, and Constraint Solvers
- In Proceedings of the First International Conference on Principles and Practice of Constraint Programming
"... When combining languages for symbolic constraints, one is typically faced with the problem of how to treat "mixed" constraints. The two main problems are (1) how to define a combined solution structure over which these constraints are to be solved, and (2) how to combine the constraint sol ..."
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Cited by 25 (3 self)
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When combining languages for symbolic constraints, one is typically faced with the problem of how to treat "mixed" constraints. The two main problems are (1) how to define a combined solution structure over which these constraints are to be solved, and (2) how to combine the constraint
Near-optimal hardness results and approximation algorithms for edge-disjoint paths and related problems
- Journal of Computer and System Sciences
, 1999
"... We study the approximability of edge-disjoint paths and related problems. In the edge-disjoint paths problem (EDP), we are given a network G with source-sink pairs (si, ti), 1 ≤ i ≤ k, and the goal is to find a largest subset of source-sink pairs that can be simultaneously connected in an edge-disjo ..."
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Cited by 108 (12 self)
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concerns EDP with the additional constraint that the routing paths be of bounded length. We show that, for any ɛ> 0, bounded length EDP is hard to approximate within m 1/2−ɛ even in undirected networks, and give an O ( √ m)-approximation algorithm for it. For directed networks, we show that even
Revisiting the tree Constraint
- In Principles and Practice of Constraint Programming, CP
"... Abstract. This paper revisits the tree constraint introduced in [2] which partitions the nodes of a n-nodes, m-arcs directed graph into a set of node-disjoint anti-arborescences for which only certain nodes can be tree roots. We introduce a new filtering algorithm that enforces gen-eralized arc-cons ..."
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Cited by 3 (1 self)
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Abstract. This paper revisits the tree constraint introduced in [2] which partitions the nodes of a n-nodes, m-arcs directed graph into a set of node-disjoint anti-arborescences for which only certain nodes can be tree roots. We introduce a new filtering algorithm that enforces gen-eralized arc
Necessary condition for path partitioning constraints
- In Proceedings of CP-AI-OR’07, volume 4510 of LNCS
, 2007
"... Abstract. Given a directed graph G, the K node-disjoint paths problem consists in finding a partition of G into K node-disjoint paths, such that each path ends up in a given subset of nodes in G. This article provides a necessary condition for the K node-disjoint paths problem which combines (1) the ..."
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Cited by 4 (1 self)
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Abstract. Given a directed graph G, the K node-disjoint paths problem consists in finding a partition of G into K node-disjoint paths, such that each path ends up in a given subset of nodes in G. This article provides a necessary condition for the K node-disjoint paths problem which combines (1
Tverberg’s theorem with constraints
- J. Combinatorial Theory, Ser. A
, 2008
"... The topological Tverberg theorem claims that for any continuous map of the (q − 1)(d + 1)-simplex σ (d+1)(q−1) to R d there are q disjoint faces of σ (d+1)(q−1) such that their images have a non-empty intersection. This has been proved for affine maps, and if q is a prime power, but not in general. ..."
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Cited by 7 (1 self)
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. The proof is based on connectivity results of chessboard-type complexes. Moreover, Tverberg’s theorem with constraints implies new lower bounds for the number of Tverberg partitions. As a consequence, we prove Sierksma’s conjecture for d = 2, and q = 3. 1
Packing Under Tolerance Constraints
, 1996
"... Let N = f1; 2; : : : ; ng and c 2 R n : A k-tuple (t 1 ; : : : ; t k ) of elements in N is called an acceptable cell if \Gamma1 k X i=1 c t i 1: We consider the problems of (i) finding the set T of all acceptable cells efficiently (ii) finding a maximum number of mutually disjoint acceptabl ..."
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Let N = f1; 2; : : : ; ng and c 2 R n : A k-tuple (t 1 ; : : : ; t k ) of elements in N is called an acceptable cell if \Gamma1 k X i=1 c t i 1: We consider the problems of (i) finding the set T of all acceptable cells efficiently (ii) finding a maximum number of mutually disjoint
Competitive Local Routing with Constraints?
, 2015
"... Let P be a set of n vertices in the plane and S a set of non-crossing line segments between vertices in P, called constraints. Two vertices are visible if the straight line segment connecting them does not properly intersect any constraints. The constrained θm-graph is constructed by partitioning th ..."
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the plane around each vertex into m disjoint cones with aperture θ = 2pi/m, and adding an edge to the ‘closest ’ visible vertex in each cone. We consider how to route on the constrained θ6-graph. We first show that no deterministic 1-local routing algorithm is o( n)-competitive on all pairs of vertices
On the inapproximability of disjoint paths and minimum steiner forest with bandwidth constraints
- Journal of Computer and Systems Sciences
"... In this paper, we study the inapproximability of several well-known optimization problems in network optimization. We show-that the max directed vertex-disjoint paths problem cannot be approximated within ratio 2 log1& = n unless NP DTIME[2 polylog n], the max directed edge-disjoint paths proble ..."
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Cited by 15 (1 self)
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In this paper, we study the inapproximability of several well-known optimization problems in network optimization. We show-that the max directed vertex-disjoint paths problem cannot be approximated within ratio 2 log1& = n unless NP DTIME[2 polylog n], the max directed edge-disjoint paths
Bound Consistency for Binary Length-Lex Set Constraints
- In Proceedings of the National Conference on Artificial Intelligence (AAAI
, 2008
"... The length-lex representation has been recently proposed for representing sets in Constraint Satisfaction Problems. The length-lex representation directly captures cardinality information, provides a total ordering for sets, and allows bound consistency on unary constraints to be enforced in time Õ( ..."
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Cited by 8 (5 self)
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(c), where c is the cardinality of the set. However, no algorithms were given to enforce bound consistency on binary constraints. This paper addresses this open issue. It presents algorithms to enforce bound consistency on disjointness and cardinality constraints in time O(c 3). Moreover, it presents a
Results 1 - 10
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202
