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基于Moldflow模拟仿真的结果,结合GA算法优化BP网络的结构,建立了模具温度,熔体温度,保压压力,注射速度等工艺参数与塑件体积收缩率的BP网络模型.获得了最优的工艺参数组合,同时预测结果与实际结果吻合.通过神经网络算法(BP)预测注塑工艺参数对塑件质量的影响,可以有效降低其他建模方法的难度和工作量,方法可以推广到塑件其他质量预测过程中. 相似文献
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Jeong Han Kim 《Random Structures and Algorithms》2003,23(2):111-132
Let ??k(n, p) be the random k‐uniform hypergraph on V = [n] with edge probability p. Motivated by a theorem of Erd?s and Rényi 7 regarding when a random graph G(n, p) = ??2(n, p) has a perfect matching, the following conjecture may be raised. (See J. Schmidt and E. Shamir 16 for a weaker version.) Conjecture. Let k|n for fixed k ≥ 3, and the expected degree d(n, p) = p(). Then (Erd?s and Rényi 7 proved this for G(n, p).) Assuming d(n, p)/n1/2 → ∞, Schmidt and Shamir 16 were able to prove that ??k(n, p) contains a perfect matching with probability 1 ? o(1). Frieze and Janson 8 showed that a weaker condition d(n, p)/n1/3 → ∞ was enough. In this paper, we further weaken the condition to A condition for a similar problem about a perfect triangle packing of G(n, p) is also obtained. A perfect triangle packing of a graph is a collection of vertex disjoint triangles whose union is the entire vertex set. Improving a condition p ≥ cn?2/3+1/15 of Krivelevich 12 , it is shown that if 3|n and p ? n?2/3+1/18, then © 2003 Wiley Periodicals, Inc. Random Struct. Alg., 23: 111–132, 2003 相似文献
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We consider a collection of n independent random subsets of [m] = {1, 2, . . . , m} that are uniformly distributed in the class of subsets of size d, and call any two subsets adjacent whenever they intersect. This adjacency relation defines a graph called the uniform random intersection graph and denoted by G n,m,d . We fix d = 2, 3, . . . and study when, as n,m → ∞, the graph G n,m,d contains a Hamilton cycle (the event denoted \( {G_{n,m,d}} \in \mathcal{H} \)). We show that \( {\mathbf{P}}\left( {{G_{n,m,d}} \in \mathcal{H}} \right) = o(1) \) for d 2 nm ?1 ? lnm ? 2 ln lnm → ?∞ and \( {\mathbf{P}}\left( {{G_{n,m,d}} \in \mathcal{H}} \right) = 1 - o(1) \) for 2nm ?1 ? lnm ? ln lnm → +∞. 相似文献
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Aniello Buonocore Enrica Pirozzi Luigia Caputo 《Statistics & probability letters》2009,79(19):2092-2097
An inductive procedure is used to obtain distributions and probability densities for the sum Sn of independent, non-equally uniform random variables. Some known results are then shown to follow immediately as special cases. Under the assumption of equally uniform random variables some new formulas are obtained for probabilities and means related to Sn. Finally, some new recursive formulas involving distributions are derived. 相似文献
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The smallest number of edges forming an n‐uniform hypergraph which is not r‐colorable is denoted by m(n,r). Erd?s and Lovász conjectured that . The best known lower bound was obtained by Radhakrishnan and Srinivasan in 2000. We present a simple proof of their result. The proof is based on the analysis of a random greedy coloring algorithm investigated by Pluhár in 2009. The proof method extends to the case of r‐coloring, and we show that for any fixed r we have improving the bound of Kostochka from 2004. We also derive analogous bounds on minimum edge degree of an n‐uniform hypergraph that is not r‐colorable. © 2014 Wiley Periodicals, Inc. Random Struct. Alg., 47, 407–413, 2015 相似文献
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Stefan Steinerberger 《Acta Mathematica Hungarica》2011,130(4):321-339
This paper generalizes earlier results on the behaviour of uniformly distributed sequences in the unit interval [0,1] to more
general domains. We devote special attention to the most interesting special case [0,1]
d
. This will naturally lead to a problem in geometric probability theory, where we generalize results by Anderssen, Brent,
Daley and Moran about random chord lengths in high-dimensional unit cubes, thereby answering a question by Bailey, Borwein
and Crandall. 相似文献
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A uniform random intersection graphG(n,m,k) is a random graph constructed as follows. Label each of n nodes by a randomly chosen set of k distinct colours taken from some finite set of possible colours of size m. Nodes are joined by an edge if and only if some colour appears in both their labels. These graphs arise in the study of the security of wireless sensor networks, in particular when modelling the network graph of the well-known key predistribution technique due to Eschenauer and Gligor.The paper determines the threshold for connectivity of the graph G(n,m,k) when n→∞ in many situations. For example, when k is a function of n such that k≥2 and m=⌊nα⌋ for some fixed positive real number α then G(n,m,k) is almost surely connected when
lim infk2n/mlogn>1, 相似文献
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We consider the following model Hr(n, p) of random r-uniform hypergraphs. The vertex set consists of two disjoint subsets V of size | V | = n and U of size | U | = (r − 1)n. Each r-subset of V × (r−1U) is chosen to be an edge of H ε Hr(n, p) with probability p = p(n), all choices being independent. It is shown that for every 0 < < 1 if P = (C ln n)/nr−1 with C = C() sufficiently large, then almost surely every subset V1 V of size | V1 | = (1 − )n is matchable, that is, there exists a matching M in H such that every vertex of V1 is contained in some edge of M. 相似文献
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Based on the analysis of stratification structure on random normed modules, we first present random strict convexity and random uniform convexity in random normed modules. Then, we establish their respective relations to classical strict and uniform convexity: in the process some known important results concerning strict convexity and uniform convexity of Lebesgue-Bochner function spaces can be obtained as a special case of our results. Further, we also give their important applications to the theory of random conjugate spaces as well as best approximation. Finally, we conclude this paper with some remarks showing that the study of geometry of random normed modules will also motivate the further study of geometry of probabilistic normed spaces. 相似文献