Xem 1-18 trên 18 kết quả Acycliciti:
  • Consider the problem of finding a large induced acyclic subgraph of a given simple digraph D = (V,E). The decision version of this problem is NP-complete and its optimization is not likely to be approximable within a ratio of O(n) for some  0. We study this problem when D is a random instance. We show that, almost surely, any maximal solution is within an o(ln n) factor from the optimal one. In addition, except when D is very sparse (having n1+o(1) edges), this ratio is in fact O(1). Thus, the optimal solution can be approximated in a much better way over random instances....

    pdf6p thulanh5 12-09-2011 16 3   Download

  • This paper proposes the “Hierarchical Directed Acyclic Graph (HDAG) Kernel” for structured natural language data. The HDAG Kernel directly accepts several levels of both chunks and their relations, and then efficiently computes the weighed sum of the number of common attribute sequences of the HDAGs. We applied the proposed method to question classification and sentence alignment tasks to evaluate its performance as a similarity measure and a kernel function. The results of the experiments demonstrate that the HDAG Kernel is superior to other kernel functions and baseline methods. ...

    pdf8p bunbo_1 17-04-2013 13 1   Download

  • Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học tạp chí toán học quốc tế đề tài: Improved bounds for the number of forests and acyclic orientations in the square lattice

    pdf18p lame_266 12-09-2011 19 3   Download

  • Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học tạp chí Department of Mathematic dành cho các bạn yêu thích môn toán học đề tài: Acyclic sets in k-majority tournaments...

    pdf7p thulanh7 05-10-2011 22 3   Download

  • Tuyển tập các báo cáo nghiên cứu khoa học trên tạp chí toán học quốc tế đề tài: Words avoiding a reflexive acyclic relation...

    pdf32p thulanh5 13-09-2011 19 2   Download

  • TTuyển tập các báo cáo nghiên cứu khoa học ngành toán học tạp chí toán học quốc tế đề tài:the Prism of the Acyclic Orientati...

    pdf6p thulanh3 10-09-2011 16 1   Download

  • Tuyển tập các báo cáo nghiên cứu khoa học trên tạp chí toán học quốc tế đề tài: k-Colour partitions of acyclic tournaments...

    pdf12p thulanh5 13-09-2011 28 1   Download

  • AC/DC I/O interface. A discrete interface that converts alternating current (AC) voltages from field devices into direct current (DC) signals that the processor can use. It can also convert DC signals into proportional AC voltages. action. A set of control instructions prompting a PLC to perform a certain control function during the execution of a sequential function chart step. acyclic message. An unscheduled message transmission. A/D. See analog-to-digital converter. address. (1) The location in a computer’s memory where particular information is stored.

    pdf25p balanghuyen 13-01-2010 77 19   Download

  • Upward planarity testing for ordered sets has the same complexity as for general digraphs (insert dummy vertices on transitive edges) [Kelly 87, Di Battista Tamassia 87]: upward planarity is equivalent to subgraph inclusion in a planar st-digraph (planar acyclic digraph with one source and one sink, both on the external face)

    pdf7p audi123 31-07-2010 61 17   Download

  • In the acyclic peer-to-peer architecture, servers communicate with each other symmetrically as peers, adopting a protocol that allows a bidirectional flow of subscriptions, advertisements, and notifications. Hence we use an undirected graph to represent the topology of this architecture. (As always, the external clients of the service use the standard client/server protocol described in Sec- tion 3.) The configuration of the connections among servers in this architecture is restricted so that the topology forms an acyclic undirected graph.

    pdf29p nhacchovina 22-03-2013 30 5   Download

  • Removing the constraint of acyclicity fromthe acyclic peer-to-peer architecture, we obtain the general peer-to-peer architecture. Like the acyclic peer-to-peer architecture, this architecture allows bidirectional communication between two servers, but the topology can form a general undirected graph, possibly having multiple paths between servers. An example is shown in Figure 7. The advantage of the general peer-to-peer architecture over the previous two architectures is that it requires less coordination and offers more flexi- bility in the configuration of connections among servers.

    pdf30p nhacchovina 22-03-2013 24 5   Download

  • Overview1.Biosynthesis of terpenes2.Biosynthesis of phenols3.Metabolism of fatty acids4.Metabolism of glucose (glycolysis)5.Anabolic pathways of fatty acidsand carbohydrates.Biosynthesis of acyclic terpenoids.Condensation of isoprene units. Formation of acyclic terpenes.Formation of monoterpenes(examples)

    pdf18p nguyenhopgh 24-05-2013 35 5   Download

  • Sensor queries involve stored data and sensor data, i.e. relations and sequences. We define a sensor query as an acyclic graph of relational and sequence operators. The inputs of a relational operator are base relations or the output of another relational operator; the inputs of a sequence operator are base sequences or the output of another sequence operator, i.e. relations are manipulated using relational operators...

    pdf12p yasuyidol 02-04-2013 14 3   Download

  • The search space of Phrase-Based Statistical Machine Translation (PBSMT) systems can be represented under the form of a directed acyclic graph (lattice). The quality of this search space can thus be evaluated by computing the best achievable hypothesis in the lattice, the so-called oracle hypothesis. For common SMT metrics, this problem is however NP-hard and can only be solved using heuristics.

    pdf10p bunthai_1 06-05-2013 24 3   Download

  • This paper presents a dependency language model (DLM) that captures linguistic constraints via a dependency structure, i.e., a set of probabilistic dependencies that express the relations between headwords of each phrase in a sentence by an acyclic, planar, undirected graph. Our contributions are three-fold. First, we incorporate the dependency structure into an n-gram language model to capture long distance word dependency. Second, we present an unsupervised learning method that discovers the dependency structure of a sentence using a bootstrapping procedure. ...

    pdf8p bunbo_1 17-04-2013 16 2   Download

  • We investigate a series of graph-theoretic constraints on non-projective dependency parsing and their effect on expressivity, i.e. whether they allow naturally occurring syntactic constructions to be adequately represented, and efficiency, i.e. whether they reduce the search space for the parser. In particular, we define a new measure for the degree of non-projectivity in an acyclic dependency graph obeying the single-head constraint. The constraints are evaluated experimentally using data from the Prague Dependency Treebank and the Danish Dependency Treebank. ...

    pdf8p bunthai_1 06-05-2013 15 2   Download

  • The osmoregulated periplasmic glucans (OPGs) produced byRhodobacter sphaeroides, a free-living organism, were isolated by trichloracetic acid treatment and gel permeation chromatography. Compounds obtained were characterized by compositional analysis, matrix-assisted laser desorption ionization mass spectrometry and nuclear magnetic resonance.R. sphaeroidespredominantly synthesizes acyclic glucan containing 18 glucose residues that canbe substituted by one to seven succinyl esters residues at the C6position of some of the glucose residues, and by one or two acetyl resi-dues....

    pdf9p research12 29-04-2013 7 1   Download

  • W e propose an apparently minor extension to Kay's (1985} notation for describing directed acyclic graphs (DAGs}. The proposed notation permits concise descriptions of phenomena which would otherwise be difficult to describe, without incurring significant extra computational overheads in the process of unification. W e illustrate the notation with examples from a categorial description of a fragment of English, and discuss the computational properties of unification of DAGs specified in this way. ...

    pdf5p buncha_1 08-05-2013 11 1   Download

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