Home About us Contact
|
Home About us Contact | ||
|
|
||
Linear Time (linear + time)
Selected AbstractsOn Resolving Conflicts Between ArgumentsCOMPUTATIONAL INTELLIGENCE, Issue 3 2000Nico Roos Argument systems are based on the idea that one can construct arguments for propositions,structured reasons justifying the belief in a proposition. Using defeasible rules, arguments need not be valid in all circumstances, therefore, it might be possible to construct an argument for a proposition as well as its negation. When arguments support conflicting propositions, one of the arguments must be defeated, which raises the question of which (sub-) arguments can be subject to defeat. In legal argumentation, metarules determine the valid arguments by considering the last defeasible rule of each argument involved in a conflict. Since it is easier to evaluate arguments using their last rules, can a conflict be resolved by considering only the last defeasible rules of the arguments involved? We propose a new argument system where, instead of deriving a defeat relation between arguments, arguments for the defeat of defeasible rules are constructed. This system allows us to determine a set of valid (undefeated) arguments in linear time using an algorithm based on a JTMS, allows conflicts to be resolved using only the last rules of the arguments, allows us to establish a relation with Default Logic, and allows closure properties such as cumulativity to be proved. We propose an extension of the argument system based on a proposal for reasoning by cases in default logic. [source] Impulse-based dynamic simulation in linear timeCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 4-5 2007Jan Bender Abstract This paper describes an impulse-based dynamic simulation method for articulated bodies which has a linear time complexity. Existing linear-time methods are either based on a reduced-coordinate formulation or on Lagrange multipliers. The impulse-based simulation has advantages over these well-known methods. Unlike reduced-coordinate methods, it handles nonholonomic constraints like velocity-dependent ones and is very easy to implement. In contrast to Lagrange multiplier methods the impulse-based approach has no drift problem and an additional stabilisation is not necessary. The presented method computes a simulation step in O(n) time for acyclic multi-body systems containing equality constraints. Closed kinematic chains can be handled by dividing the model into different acyclic parts. Each of these parts is solved independently from each other. The dependencies between the single parts are solved by an iterative method. In the same way inequality constraints can be integrated in the simulation process in order to handle collisions and permanent contacts with dynamic and static friction. Copyright © 2007 John Wiley & Sons, Ltd. [source] Deterministic parallel selection algorithms on coarse-grained multicomputersCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 18 2009M. Cafaro Abstract We present two deterministic parallel Selection algorithms for distributed memory machines, under the coarse-grained multicomputer model. Both are based on the use of two weighted 3-medians, that allows discarding at least 1/3 of the elements in each iteration. The first algorithm slightly improves the current experimentally fastest algorithm by Saukas and Song where at least 1/4 of the elements are discarded in each iteration, while the second one is a fast, special purpose algorithm working for a particular class of input, namely an input that can be sorted in linear time using RadixSort. Copyright © 2009 John Wiley & Sons, Ltd. [source] Efficient probabilistic reasoning in BNs with mutual exclusion and context-specific independenceINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 8 2004Carmel Domshlak Prior work has shown that context-specific independence (CSI) in Bayes networks can be exploited to speed up belief updating. We examine how networks with variables exhibiting mutual exclusion (e.g., "selector variables"), as well as CSI, can be efficiently updated. In particular, directed-path singly connected and polytree networks that have an additional common selector variable can be updated in linear time (given null and general conjunctive evidence, respectively), where quadratic time would be needed without the mutual exclusion requirement. The above results have direct applications, as such network topologies can be used in predicting the ramifications of user selection in some multimedia data browsing systems. © 2004 Wiley Periodicals, Inc. Int J Int Syst 19: 703,725, 2004. [source] Mixed search number and linear-width of interval and split graphsNETWORKS: AN INTERNATIONAL JOURNAL, Issue 3 2010Fedor V. Fomin Abstract We show that the mixed search number and the linear-width of interval graphs and of split graphs can be computed in linear time and in polynomial time, respectively. © 2009 Wiley Periodicals, Inc. NETWORKS, 2010 [source] The bi-criteria doubly weighted center-median path problem on a treeNETWORKS: AN INTERNATIONAL JOURNAL, Issue 4 2006J. Puerto Abstract Given a tree network T with n nodes, let ,,L be the subset of all discrete paths whose length is bounded above by a prespecified value L. We consider the location of a path-shaped facility P , ,,L, where customers are represented by the nodes of the tree. We use a bi-criteria model to represent the total transportation cost of the customers to the facility. Each node is associated with a pair of nonnegative weights: the center-weight and the median-weight. In this doubly weighted model, a path P is assigned a pair of values (MAX(P),SUM(P)), which are, respectively, the maximum center-weighted distance and the sum of the median-weighted distances from P to the nodes of the tree. Viewing ,,L and the planar set {(MAX(P),SUM(P)) : P , ,,L} as the decision space and the bi-criteria or outcome space respectively, we focus on finding all the nondominated points of the bi-criteria space. We prove that there are at most 2n nondominated outcomes, even though the total number of efficient paths can be ,(n2), and they can all be generated in O(n log n) optimal time. We apply this result to solve the cent-dian model, whose objective is a convex combination of the weighted center and weighted median functions. We also solve the restricted models, where the goal is to minimize one of the two functions MAX or SUM, subject to an upper bound on the other one, both with and without a constraint on the length of the path. All these problems are solved in linear time, once the set of nondominated outcomes has been obtained, which in turn, results in an overall complexity of O(n log n). The latter bounds improve upon the best known results by a factor of O(log n). © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 47(4), 237,247 2006 [source] Flexibility of Steiner trees in uniform orientation metricsNETWORKS: AN INTERNATIONAL JOURNAL, Issue 3 2005M. Brazil Abstract We present some fundamental flexibility properties for minimum length networks (known as Steiner minimum trees) interconnecting a given set of points in an environment in which edge segments are restricted to , uniformly oriented directions. These networks are referred to as ,-SMTs. They promise to play an increasingly important role in the future of optimal wire routing in VLSI physical design, particularly for the next generation of VLSI circuits. In this article we develop the concept of a flexibility polygon for a ,-SMT, which is a region representing the union of all ,-SMTs with the same topology on a given set of points. We show that this polygon can be constructed, for a given point set and given topology, in linear time. We discuss some of the future applications of this polygon, which can be thought of as a geometric representation of the amount of flexibility inherent in a given ,-SMT. © 2005 Wiley Periodicals, Inc. NETWORKS, Vol. 46(3), 142,153 2005 [source] Robust location problems with pos/neg weights on a treeNETWORKS: AN INTERNATIONAL JOURNAL, Issue 2 2001Rainer E. Burkard Abstract In this paper, we consider different aspects of robust 1-median problems on a tree network with uncertain or dynamically changing edge lengths and vertex weights which can also take negative values. The dynamic nature of a parameter is modeled by a linear function of time. A linear algorithm is designed for the absolute dynamic robust 1-median problem on a tree. The dynamic robust deviation 1-median problem on a tree with n vertices is solved in O(n2 ,(n) log n) time, where ,(n) is the inverse Ackermann function. Examples show that both problems do not possess the vertex optimality property. The uncertainty is modeled by given intervals, in which each parameter can take a value randomly. The absolute robust 1-median problem with interval data, where vertex weights might also be negative, can be solved in linear time. The corresponding deviation problem can be solved in O(n2) time. © 2001 John Wiley & Sons, Inc. [source] A strategy for high-resolution protein identification in surface-enhanced laser desorption/ionization mass spectrometry: Calgranulin A and chaperonin 10 as protein markers for endometrial carcinomaPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 7 2005Jingzhong Guo Abstract Surface-enhanced laser desorption/ionization-mass spectrometry (SELDI-MS) has conventionally been practiced on linear time of flight (TOF) which has low mass accuracy and resolution. Here we demonstrate in an examination of both malignant and nonmalignant endometrial tissue homogenates that high mass accuracy and resolution in the MS stage are crucial. Using a commercially available quadrupole/TOF (QqTOF), we were able to resolve two potential cancer markers, subsequently identified off-line as chaperonin 10 and calgranulin A, that differ by 8 Da in mass. Two off-line protein identification protocols were developed: the first was based on size-exclusion chromatography (SEC), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), protein extraction, trypsin digestion, and matrix-assisted laser desorption/ionization-tandem MS (MALDI-MS/MS); the second on SEC and shotgun nano-liquid chromatography (nanoLC)-MS/MS. Analyses on a cohort of 44 endometrial homogenates showed 22 out of 23 nonmalignant samples had nondetectable to very low abundance of chaperonin 10 and calgranulin A; 17 of the 21 malignant samples had detectable to abundant levels of both proteins. Immunohistochemical staining of a tissue microarray of 32 samples showed that approximately half of malignant endometrial tissues exhibited positive staining for calgranulin A in the malignant epithelium, while 9 out of 10 benign tissues exhibited negative epithelial staining. In addition, macrophages/granulocytes in malignant as well as nonmalignant tissues showed positive staining. No immunostaining occurred in stroma or myometrium. Calgranulin A, in combination with chaperonin 10 and other proteins, may eventually constitute a panel of markers to permit diagnosis and screening of endometrial cancer. [source] Uniform random sampling of planar graphs in linear time,RANDOM STRUCTURES AND ALGORITHMS, Issue 4 2009Éric Fusy Abstract This article introduces new algorithms for the uniform random generation of labelled planar graphs. Its principles rely on Boltzmann samplers, as recently developed by Duchon, Flajolet, Louchard, and Schaeffer. It combines the Boltzmann framework, a suitable use of rejection, a new combinatorial bijection found by Fusy, Poulalhon, and Schaeffer, as well as a precise analytic description of the generating functions counting planar graphs, which was recently obtained by Giménez and Noy. This gives rise to an extremely efficient algorithm for the random generation of planar graphs. There is a preprocessing step of some fixed small cost; and the expected time complexity of generation is quadratic for exact-size uniform sampling and linear for uniform approximate-size sampling. This greatly improves on the best previously known time complexity for exact-size uniform sampling of planar graphs with n vertices, which was a little over O(n7). © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2009 [source] A simple and linear time randomized algorithm for computing sparse spanners in weighted graphs,RANDOM STRUCTURES AND ALGORITHMS, Issue 4 2007Surender Baswana Abstract Let G = (V,E) be an undirected weighted graph on |V | = n vertices and |E| = m edges. A t -spanner of the graph G, for any t , 1, is a subgraph (V,ES), ES , E, such that the distance between any pair of vertices in the subgraph is at most t times the distance between them in the graph G. Computing a t -spanner of minimum size (number of edges) has been a widely studied and well-motivated problem in computer science. In this paper we present the first linear time randomized algorithm that computes a t -spanner of a given weighted graph. Moreover, the size of the t -spanner computed essentially matches the worst case lower bound implied by a 43-year old girth lower bound conjecture made independently by Erd,s, Bollobás, and Bondy & Simonovits. Our algorithm uses a novel clustering approach that avoids any distance computation altogether. This feature is somewhat surprising since all the previously existing algorithms employ computation of some sort of local or global distance information, which involves growing either breadth first search trees up to ,(t)-levels or full shortest path trees on a large fraction of vertices. The truly local approach of our algorithm also leads to equally simple and efficient algorithms for computing spanners in other important computational environments like distributed, parallel, and external memory. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2007 [source] The use of the past and the present in the clinical setting Pasts and presentsTHE INTERNATIONAL JOURNAL OF PSYCHOANALYSIS, Issue 6 2006JANINE PUGET The author provides a brief summary of Latin American literature concerning temporality. She shows that a common theme throughout all these papers is that the analytical relationship is considered to be bipersonal and symmetrical, thus demonstrating a concern for establishing the basis by which social subjectivity can be reconsidered. This literature displaces the idea of linear time from its central position and introduces other measures of time. The analytical relationship takes place not only in the past but also in a newly created present. This is the ongoing present, of what is happening now, instantaneous and without a prior history attached to it. This leads the author to suggest that there is a present to one's history and a history to one's present. She then analyses the consequences of this proposition by examining some clinical material where she attempts to pinpoint those instances in which the analyst may have reacted defensively, tending to position himself in the analysand's past instead of being able to take action in the present. Clinical material from the IJP is used. [source] | |||||||||||||