Search results for "ARCHITECTURE"
showing 10 items of 3706 documents
Branch-and-cut algorithms for the vehicle routing problem with trailers and transshipments
2013
This article studies the vehicle routing problem with trailers and transshipments VRPTT, a practically relevant, but challenging, generalization of the classical vehicle routing problem. The article makes three contributions: i Building on a nontrivial network representation, two mixed-integer programming formulations for the VRPTT are proposed. ii Based on these formulations, five different branch-and-cut algorithms are developed and implemented. iii The computational behavior of the algorithms is analyzed in an extensive computational study, using a large number of test instances designed to resemble real-world VRPTTs.Copyright © 2013 Wiley Periodicals, Inc. NETWORKS, Vol. 631, 119-133 20…
Circuit-Elimination based Link-State Routing in Mobile Ad-hoc Networks
2007
Circuit-elimination based connected dominating set formation is an efficient technique for reducing routing overhead in mobile ad hoc networks. In this paper, we propose a new message dissemination algorithm which utilizes such techniques to reduce the number of nodes that generate or forward link state advertisements in link state routing protocols. Simulation results with both static and dynamic network topologies demonstrate the potential of the proposed algorithm to reduce routing overhead, compared with a benchmark link state routing protocol, OLSR.
Simulating spin models on GPU
2010
Over the last couple of years it has been realized that the vast computational power of graphics processing units (GPUs) could be harvested for purposes other than the video game industry. This power, which at least nominally exceeds that of current CPUs by large factors, results from the relative simplicity of the GPU architectures as compared to CPUs, combined with a large number of parallel processing units on a single chip. To benefit from this setup for general computing purposes, the problems at hand need to be prepared in a way to profit from the inherent parallelism and hierarchical structure of memory accesses. In this contribution I discuss the performance potential for simulating…
On the analysis of a random walk-jump chain with tree-based transitions and its applications to faulty dichotomous search
2018
Random Walks (RWs) have been extensively studied for more than a century [1]. These walks have traditionally been on a line, and the generalizations for two and three dimensions, have been by extending the random steps to the corresponding neighboring positions in one or many of the dimensions. Among the most popular RWs on a line are the various models for birth and death processes, renewal processes and the gambler’s ruin problem. All of these RWs operate “on a discretized line”, and the walk is achieved by performing small steps to the current-state’s neighbor states. Indeed, it is this neighbor-step motion that renders their analyses tractable. When some of the transitions are to non-ne…
A heuristic method for estimating attribute importance by measuring choice time in a ranking task
2012
The evaluation of a product or service in terms of its attributes has been broadly studied in marketing, management and decision sciences. However, methods for finding important attributes have theoretical and practical limitations. The former are related to the selection of the most appropriate model; the latter are due to large number of variables that affect the specific experimental context. This study aims to present a new methodology that captures attribute preferences from a respondent and in particular, by using the choice time in a ranking task, it allows to indirectly obtain the importance weights for several tested attributes through a simple, fast and inexpensive procedure. More…
Selfish vs. Unselfish Optimization of Network Creation
2005
We investigate several variants of a network creation model: a group of agents builds up a network between them while trying to keep the costs of this network small. The cost function consists of two addends, namely (i) a constant amount for each edge an agent buys and (ii) the minimum number of hops it takes sending messages to other agents. Despite the simplicity of this model, various complex network structures emerge depending on the weight between the two addends of the cost function and on the selfish or unselfish behaviour of the agents.
The 1970 US Draft Lottery Revisited: A Spatial Analysis
2004
Summary We revise the result of the 1970 selective service draft lottery in the USA following an open question that was suggested by Fienberg in a paper published in Science in 1971. The result of the drawings can be viewed as a particular spatial pattern which can be analysed by using general spatial tools adapted to our context. Approaches for assessing the complete spatial randomness for this spatial process on a finite support are proposed. More specifically, these approaches involve the number of events in a square window and a k(r)-based function used to analyse stationary spatial point processes.
DRUDIT: Web-based DRUgs DIscovery Tools to design small molecules as modulators of biological targets
2019
Abstract Motivation New in silico tools to predict biological affinities for input structures are presented. The tools are implemented in the DRUDIT (DRUgs DIscovery Tools) web service. The DRUDIT biological finder module is based on molecular descriptors that are calculated by the MOLDESTO (MOLecular DEScriptors TOol) software module developed by the same authors, which is able to calculate more than one thousand molecular descriptors. At this stage, DRUDIT includes 250 biological targets, but new external targets can be added. This feature extends the application scope of DRUDIT to several fields. Moreover, two more functions are implemented: the multi- and on/off-target tasks. These tool…
TESF Methodology for Statistics Education Improvement
2010
The need for universities to achieve excellence in the services they provide has been the subject of research for several decades. The idea of involving students and recognizing the importance of their opinions has led to the creation of various models and tools. This paper focuses on teaching, a central service from which improvement actions of an academic institution should always begin. The article reviews and updates the previously developed Teaching Experiments and Student Feedback methodology. The methodology, which is primarily addressed to statistics teachers, allows practical aspects to be organized and decisions to be made based on data that has been collected from students and sc…
Gossip: The Architecture of SpreadPlots
2003
A spreadplot is a visualization that simultaneously shows several different views of a dataset or model. The individual views can be dynamic, can support high-interaction direct manipulation, and can be algebraically linked with each other, possibly via an underlying statistical model. Thus, when a data analyst changes the information shown in one view of a statistical model, the changes can be processed by the model and instantly represented in the other views. Spreadplots simplify the analyst's task when many different plots are relevant to the analysis at hand, as is the case in regression analysis, where there are many plots that can be used for model building and diagnosis. On the othe…