We show that for arbitrary positive integers a(1),..., a(m), with probability 6/pi(2) + o(1), the gcd of two linear combinations of these integers with rather small random integer coefficients coincides with gcd(a(1),...
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We show that for arbitrary positive integers a(1),..., a(m), with probability 6/pi(2) + o(1), the gcd of two linear combinations of these integers with rather small random integer coefficients coincides with gcd(a(1),..., a(m)). This naturally leads to a probabilistic algorithm for computing the gcd of several integers, with probability 6/pi(2) + o(1), via just one gcd of two numbers with about the same size as the initial data ( namely the above linear combinations). This algorithm can be repeated to achieve any desired confidence level.
In the job shop scheduling problem (JSP), a finite set of jobs is processed on a finite set of machines under certain constraints, such that the maximum completion time of the jobs is minimized. In this paper, we desc...
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In the job shop scheduling problem (JSP), a finite set of jobs is processed on a finite set of machines under certain constraints, such that the maximum completion time of the jobs is minimized. In this paper, we describe a parallel greedy randomized adaptive search procedure (GRASP) with path-relinking for the JSP. Independent and cooperative parallelization strategies are described and implemented. Computational experience on a large set of standard test problems indicates that the parallel GRASP with path-relinking finds good-quality approximate solutions of the JSP. (C) 2003 Elsevier Science B.V. All rights reserved.
This paper presents an algorithm for the traveling salesman problem in k-dimensional Euclidean space. For n points independently uniformly distributed in a set $\mathbb{E}$, we show that, for any choice of a function ...
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This paper presents an algorithm for the traveling salesman problem in k-dimensional Euclidean space. For n points independently uniformly distributed in a set $\mathbb{E}$, we show that, for any choice of a function $\sigma $ of n increasing to infinity with n more slowly than n, we can adjust the algorithm so that, in probability, the time taken by the algorithm will be of order less than that of $n\sigma (n)$ as $n \to \infty $. The algorithm puts the n points in a cyclic order, and we also show that, with probability one, the length of the corresponding tour (that is, the sum of the n distances between adjacent points in the order given) will be asymptotic to the minimal tour length as $n \to \infty $. The latter is known (also with probability one) to be asymptotic to $\beta _k v(\mathbb{E})^p n^q $, where $\beta _k $ is a constant depending only on the dimension k, $v(\mathbb{E})$ is the volume of the set $\mathbb{E}$, $p = 1/k$, and $q = 1 - p$. Our result is stronger, and the algorithm is faster, than any other we have been able to find in the literature.
Background:The reconstruction of clonal haplotypes and their evolutionary history in evolving populations is a common problem in both microbial evolutionary biology and cancer *** clonal theory of evolution provides a...
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Background:The reconstruction of clonal haplotypes and their evolutionary history in evolving populations is a common problem in both microbial evolutionary biology and cancer *** clonal theory of evolution provides a theoretical framework for modeling the evolution of ***:In this paper,we review the theoretical framework and assumptions over which the clonal reconstruction problem is *** formally define the problem and then discuss the complexity and solution space of the *** methods have been proposed to find the phylogeny that best explains the observed *** categorize these methods based on the type of input data that they use(space-resolved or time-resolved),and also based on their computational formulation as either combinatorial or *** is crucial to understand the different types of input data because each provides essential but distinct information for drastically reducing the solution space of the clonal reconstruction *** information provided by single cell sequencing or from whole genome sequencing of randomly isolated clones can also improve the accuracy of clonal *** briefly review the existing algorithms and their *** we summarize the tools that are developed for either directly solving the clonal reconstruction problem or a related computational ***:In this review,we discuss the various formulations of the problem of inferring the clonal evolutionary history from allele frequeny data,review existing algorithms and catergorize them according to their problem formulation and solution *** note that most of the available clonal inference algorithms were developed for elucidating tumor evolution whereas clonal reconstruction for unicellular genomes are less *** conclude the review by discussing more open problems such as the lack of benchmark datasets and comparison of performance between available tools.
Due to deep automation, the configuration of many Cloud infrastructures is static and homogeneous, which, while easing administration, significantly decreases a potential attacker's uncertainty on a deployed Cloud...
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ISBN:
(纸本)9781479920037
Due to deep automation, the configuration of many Cloud infrastructures is static and homogeneous, which, while easing administration, significantly decreases a potential attacker's uncertainty on a deployed Cloud-based service and hence increases the chance of the service being compromised. Moving-target defense (MTD) is a promising solution to the configuration staticity and homogeneity problem. This paper presents our findings on whether and to what extent MTD is effective in protecting a Cloud-based service with heterogeneous and dynamic attack surfaces-these attributes, which match the reality of current Cloud infrastructures, have not been investigated together in previous works on MTD in general network settings. We 1) formulate a Cloud-based service security model that incorporates Cloud-specific features such as VM migration/snapshotting and the diversity/compatibility of migration, 2) consider the accumulative effect of the attacker's intelligence on the target service's attack surface, 3) model the heterogeneity and dynamics of the service's attack surfaces, as defined by the (dynamic) probability of the service being compromised, as an S-shaped generalized logistic function, and 4) propose a probabilistic MTD service deployment strategy that exploits the dynamics and heterogeneity of attack surfaces for protecting the service against attackers. Through simulation, we identify the conditions and extent of the proposed MTD strategy's effectiveness in protecting Cloud-based services. Namely, 1) MTD is more effective when the service deployment is dense in the replacement pool and/or when the attack is strong, and 2) attack-surface heterogeneity-and-dynamics awareness helps in improving MTD's effectiveness.
This paper deals with the design of scheduling logics for Networked Control Systems (NCSs) whose communication networks have limited capacity. We assume that only a subset of the plants can communicate with their cont...
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This paper deals with the design of scheduling logics for Networked Control Systems (NCSs) whose communication networks have limited capacity. We assume that only a subset of the plants can communicate with their controllers at any time instant. Our contributions are twofold. First, we present a probabilistic algorithm to design scheduling logics that, under certain conditions on the plant and controller dynamics and the capacity of the network, ensure stochastic stability of each plant in an NCS. Second, given the plant dynamics and the capacity of the network, we design static state-feedback controllers such that the conditions for stability under our scheduling logics are satisfied. The main apparatus for our analysis is a Markovian jump linear system representation of the individual plants in an NCS. Our stability conditions involve sets of matrix inequalities. We present numerical experiments to demonstrate our results. Copyright (C) 2022 The Authors.
A fractal is a pattern that emerges from the repetition of natural rules at various sizes. Fractal dimension, typically referred to as the space-filling property, offers a basis for evaluating surface roughness. The s...
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We study testing of nonlinear operators;we want to test whether an implementation operator conforms to a specification operator. The problem is difficult, since there can be infinitely many possible inputs but we can ...
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