Search results for "Data structure"
showing 10 items of 441 documents
Numerical approximation of mixed models for digital integrated circuits
1991
To analyse an electrical network many CAD (Computer Aided Design) circuit simulators are available today. The most well-known is probably SPICE -Nagel [1975]. Although this type of simulator is able to precisely compute the transient performances (as delay time), the usage of complete models of devices implies an extremely high time consumption. So, the circuit simulators are unappropriate for the initial stage of VLSI design where a high speed timing analyser (“timing simulator”) is required. To this goal, alternative approaches using either simpler device models or simpler numerical algorithms or easily computable formulae for delay time approximation, have been developed in the past deca…
New Encodings of Pseudo-Boolean Constraints into CNF
2009
International audience; This paper answers affirmatively the open question of the existence of a polynomial size CNF encoding of pseudo-Boolean (PB) constraints such that generalized arc consistency (GAC) is maintained through unit propagation (UP). All previous encodings of PB constraints either did not allow UP to maintain GAC, or were of exponential size in the worst case. This paper presents an encoding that realizes both of the desired properties. From a theoretical point of view, this narrows the gap between the expressive power of clauses and the one of pseudo-Boolean constraints.
Tabu search with strategic oscillation for the quadratic minimum spanning tree
2014
The quadratic minimum spanning tree problem consists of determining a spanning tree that minimizes the sum of costs of the edges and pairs of edges in the tree. Many algorithms and methods have been proposed for this hard combinatorial problem, including several highly sophisticated metaheuristics. This article presents a simple Tabu Search (TS) for this problem that incorporates Strategic Oscillation (SO) by alternating between constructive and destructive phases. The commonalties shared by this strategy and the more recently introduced methodology called iterated greedy search are shown and implications of their differences regarding the use of memory structures are identified. Extensive …
Guided local search for the optimal communication spanning tree problem
2011
This paper considers the optimal communication spanning tree (OCST) problem. Previous work analyzed features of high-quality solutions. Consequently, integrating this knowledge into a metaheuristic increases its performance for the OCST problem. In this paper, we present a guided local search (GLS) approach which dynamically changes the objective function to guide the search process into promising areas. In contrast to traditional approaches which reward promising solution features by favoring edges with low weights pointing towards the tree's center, GLS penalizes low-quality edges with large weights that do not point towards the tree's center.
A novel XML document structure comparison framework based-on sub-tree commonalities and label semantics
2012
International audience; XML similarity evaluation has become a central issue in the database and information communities, its applications ranging over document clustering, version control, data integration and ranked retrieval. Various algorithms for comparing hierarchically structured data, XML documents in particular, have been proposed in the literature. Most of them make use of techniques for finding the edit distance between tree structures, XML documents being commonly modeled as Ordered Labeled Trees. Yet, a thorough investigation of current approaches led us to identify several similarity aspects, i.e., sub-tree related structural and semantic similarities, which are not sufficient…
Longest Common Subsequence from Fragments via Sparse Dynamic Programming
1998
Sparse Dynamic Programming has emerged as an essential tool for the design of efficient algorithms for optimization problems coming from such diverse areas as Computer Science, Computational Biology and Speech Recognition [7,11,15]. We provide a new Sparse Dynamic Programming technique that extends the Hunt-Szymanski [2,9,8] paradigm for the computation of the Longest Common Subsequence (LCS) and apply it to solve the LCS from Fragments problem: given a pair of strings X and Y (of length n and m, resp.) and a set M of matching substrings of X and Y, find the longest common subsequence based only on the symbol correspondences induced by the substrings. This problem arises in an application t…
CONSTRUCTING, BOOTSTRAPPING, AND COMPARING MORPHOMETRIC AND PHYLOGENETIC TREES: A CASE STUDY OF NEW WORLD MONKEYS (PLATYRRHINI, PRIMATES)
2005
Morphometric data sets are often phenetically analyzed by using various kinds of spatial, metric, or nonmetric multivariate analyses. Such methods produce results that are difficult to compare directly with molecular or morphological phylogenetic hypotheses, which are usually expressed by using nonspatial tree representations. Therefore, it is useful in a comparative approach to analyze, and above all to visualize, morphometric pairwise relationships as tree structures. For this purpose, several additive or ultrametric methods exist, which often return different topologies for the same data set. Objective criteria are thus needed to identify the tree-building algorithm (or algorithm family)…
Strategic sharing of a costly network
2012
We study minimum cost spanning tree problems for a set of users connected to a source. Prim’s algorithm provides a way of finding the minimum cost tree mm. This has led to several definitions in the literature, regarding how to distribute the cost. These rules propose different cost allocations, which can be understood as compensations and/or payments between players, with respect to the status quo point: each user pays for the connection she uses to be linked to the source. In this paper we analyze the rationale behind a distribution of the minimum cost by defining an a priori transfer structure. Our first result states the existence of a transfer structure such that no user is willing to …
"Efficiency in the SR3$\ell$ region with $\ell=$$\tau$" of "Search for trilepton resonances from chargino and neutralino pair production in $\sqrt{s}…
2021
The combined $\tilde\chi^{\pm}_{1}\tilde\chi^{\mp}_{1} + \tilde\chi^{\pm}_{1}\tilde\chi^{0}_{1}$ reconstruction efficiencies in the SR3$\ell$ region. Results are given as a function of $\tilde\chi^{\pm}_{1}/\tilde\chi^{0}_{1}$ mass and branching fraction to Z bosons, and are derived separately when requiring that the charged-lepton decays of $\tilde\chi^{\pm}_{1}/\tilde\chi^{0}_{1}$ are into $\tau$-leptons only
"Triangle, Efficiency in SR3$\ell$, $\ell=(e, \mu, \tau)$" of "Search for trilepton resonances from chargino and neutralino pair production in $\sqrt…
2021
The combined $\tilde\chi^{\pm}_{1}\tilde\chi^{\mp}_{1} + \tilde\chi^{\pm}_{1}\tilde\chi^{0}_{1}$ reconstruction efficiencies in the SR3$\ell$ region for $\tilde\chi^{\pm}_{1}/\tilde\chi^{0}_{1}$ masses of 700 GeV. Results are given as a function of the branching fractions to Z and Higgs bosons