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We present several new standard and differential approximation results for the P 4 -partition problem using the Hassin and Rubinstein algorithm [Information Processing Letters 63 (1997) 63-67]. ... Those results concern both minimization and maximization versions of the problem. ... Acknowledgements Many thanks to two anonymous referees for pertinent and useful comments and suggestions. ...doi:10.1016/j.jda.2007.01.006 fatcat:3znqtvs27zb4rj2r4hrit3aizm
The resulting method is suitable for scientific computations like irregular finite elements or differences performed on hypercube or mesh architecture machines. ... This algorithm allows for arbitrary nonnegative weights on both vertices and edges to model inhomogeneous computation and communication. ... The ideas in this paper have evolved through discussions with many people including Horst Simon, Alex Pothen, Louis Romero, Ray Tuminaro, John Shadid, and Steve Plimpton. ...doi:10.1137/0916028 fatcat:p2bhchy7urhcbaodf2sdsgiziu
Using l-l correspondence between ultrametric partitions of a weighted complete graph K(w) on a finite set X and ultrametrics on X, the computational complexity of the approximation of w by means of an ... As a main result. a polynomial algorithm that solves the problem under some 'min-max' criterion is developed. ... We shall show that the same result is valid for problem (P4).3.6. Theorem. Problem (P4) is NP-complete.Proof. Clearly, problem (P4) is in the class NP. Now we shall exhibit a polynomial ). ...doi:10.1016/0020-0190(88)90090-7 fatcat:6qvnct5sczghfop5tcdzmcgoqu
Summary: “We give the first approximation algorithm for the node-weighted Steiner tree problem. Its performance guarantee is within a constant factor of the best possible unless P > NP. ... This improves previous bounds for the problem. ...
98m:68211 98m:68211 68R10 68Q25 Jansen, Klaus (D-TRR; Trier) Approximation results for the optimum cost chromatic partition problem. ... Summary: “In this paper, we study the optimum cost chromatic partition (OCCP) problem for several graph classes. ...
For those hard problems, we provide a pseudo polynomial time algorithm. An FPTAS for obtaining an approximate e¢ cient schedule is provided as well. ... Four di¤erent problem variations for dealing with the two criteria are studied. ... Methodology and Main Results Polynomial Time Solution for the P1 Problem Analysis of Problems P2-P4 For the P2-P4 variations, we show that the problems are N P-hard for any given set of positional ...doi:10.1007/s10878-010-9350-6 fatcat:zii5psuq3fd2vauzk4wngt2q5a
Summary: “Given arbitrary positive weights associated with edges, the maximum cut problem is to find a cut of the maximum cardinality (or weight in general) that partitions the graph G into X and XY. ... The bound on maxcut k- coloring is also extended to find an approximation bound for the maximum k-covering problem. ...
We propose a new concept called Compact Steiner Tree (CSTree), which can be used to approximate the Steiner tree problem for answering top-k keyword queries efficiently. ... The experimental results show that our method achieves high search efficiency and result quality comparing to existing state-of-the-art approaches. ... To address the above-mentioned problems, we propose in this paper a polynomial time approximate solution for the minimum Steiner tree problem with a theoretical bound. ...doi:10.1109/icde.2009.196 dblp:conf/icde/LiZFW09 fatcat:4jvtfsz2crdyjeeo5zhjy4m6j4
Lecture Notes in Computer Science
The problem to be solved is the design of Radial Basis Function Neural Networks (RBFNNs) that approximate a function. ... The experiments will show how, as in the real world, if the different island evolve specific aspects of the RBFNNs, the results are improved. ... of the Structuring the European Research Area programme, contract number RII3-CT-2003-506079. ...doi:10.1007/11941439_135 fatcat:672vnzrj2bbb3mzfsotqvgxjoe
In contrast to the non-parametric case the resulting smooth curve is invariant under rotation of the co-ordinate system. ... Moreover, for a certain choice of the parameters (defining the functional to be minimized) it may be interpreted as a minimizer of the strain energy. ... In all cases (with exception of the "3") 5 points PO , ... . P4 were given, with P4 = P0 for the "0" and P4 = P1 for the "6" and the "9", respectively. ...doi:10.4171/zaa/449 fatcat:nqyi2ofep5ho3btcxuohkdwfli
Besides probabilistic databases, these results can also benefit the problem of approximate query evaluation in relational databases, since the bounds expressed by queries can be computed in polynomial ... This paper investigates the problem of approximating conjunctive queries without self-joins on probabilistic databases by lower and upper bounds that can be computed more efficiently. ... This research was funded by the FP7 ERC grant agreement FOX number FP7-ICT-233599. ...doi:10.1145/1938551.1938575 dblp:conf/icdt/FinkO11 fatcat:b3dzgi4aifbe5dg36g25ux53ai
Computers & Fluids
In both cases, flow quantities of interest from the simulation results compare favorably with the reference data and near-perfect linear parallel scaling is achieved. ... The RBVMS formulation and its suitability and accuracy for turbulent flow in a moving domain are presented. ... Acknowledgement We thank the Texas Advanced Computing Center (TACC) at the University of Texas at Austin for providing HPC resources that have contributed to the research results reported within this paper ...doi:10.1016/j.compfluid.2011.05.002 fatcat:62r6gmafvjf5fb2anqisl55saq
We formulate this partition assignment problem into a balanced edge partitioning problem, and evaluate it with simulations on realistic topologies. ... Bloom-filter based source-routed multicast remedies this problem by moving the state from the routers to the packets. ... For this, we formulate the XBF design problem into a balanced edge partition problem, and present an intelligent partition algorithm that adopts the traffic-aware weighting scheme in order to minimise ...arXiv:1602.05853v1 fatcat:ypvclbaaajbgbnyz7jdors2dq4
Physical Review D
We propose a method to calculate the canonical partition function by fixing the total quark number introducing approximations allowed in the low density region. ... We discuss the nature of the phase transition for lattice QCD at finite temperature and density. ... I also wish to thank the Sumitomo Foundation for their financial assistance (No. 050408). ...doi:10.1103/physrevd.78.074507 fatcat:meurikzyovbhfm4vqazmgnchju
To tackle the latter, we introduce a novel physically-inspired, virtual-voltage approximation that leads to provable lower and upper bounds on the solution of the original problem. ... We adopt a semidefinite programming formulation for the OPF problem which, however, remains nonconvex due to the presence of discrete variables and bilinear products between the decision variables. ... Even though this recursive spectral partitioning does not in general lead to an n-optimal partition, we can characterize a lower bound for the sum of weights for each iteration l of the recursive partitioning ...arXiv:1710.02970v3 fatcat:3ofcqx6fffdk7ddrbxqraln56e
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