一类固定工件排序问题算法研究

针对一类＂可用机器数有限,存在机器与工件间匹配约束,以机器-工件分配成本最小为目标＂的固定工件排序问题,以固定工件的开始时刻、结束时刻为基准构建网络时序图,将＂机器-工件＂分配过程看成网络时序图中的网络流问题,并设计排序问题的模拟退火算法。通过算例发现：算法平均CPU时间为32.9秒,总成本最大误差为0.07%,时间复杂度为O（M（m3＋mn））,空间复杂度为O（m2n）。结果表明：算法为多项式算法,且可行。     

太原市迎泽公园景观空间分析

太原市迎泽公园位于市中心,是解放后兴建的第一个公共园林,其空间利用率很高。公园空间布局以主轴和副轴相交织形成景观,是传统园林空间布局手法与现代空间理念结合较好的园林。从迎泽公园轴线入手,着重对主轴线、副轴线及轴线上的主要景观空间进行分析。总结迎泽公园景观空间特征,旨在探讨公共园林空间如何能够有效地利用中国传统造园手法更好地表达空间景观,探索新时期下综合性园林空间的布局方法。     

An Asymmetric Kernel Estimator of Density Function for Stationary Associated Sequences

Here, we apply the smoothing technique proposed by Chaubey et al. (2007 Chaubey , Y. P. , Sen , A. , Sen , P. K. ( 2007 ). A new smooth density estimator for non-negative random variables. Technical Report No. 1/07. Department of Mathematics and Statistics, Concordia University, Montreal, Canada . [Google Scholar]) for the empirical survival function studied in Bagai and Prakasa Rao (1991 Bagai , I. , Prakasa Rao , B. L. S. ( 1991 ). Estimation of the survival function for stationary associated processes . Statist. Probab. Lett. 12 : 385 – 391 .[Crossref], [Web of Science ®] , [Google Scholar]) for a sequence of stationary non-negative associated random variables.The derivative of this estimator in turn is used to propose a nonparametric density estimator. The asymptotic properties of the resulting estimators are studied and contrasted with some other competing estimators. A simulation study is carried out comparing the recent estimator based on the Poisson weights (Chaubey et al., 2011 Chaubey , Y. P. , Dewan , I. , Li , J. ( 2011 ). Smooth estimation of survival and density functions for a stationary associated process using poisson weights . Statist. Probab. Lett. 81 : 267 – 276 .[Crossref], [Web of Science ®] , [Google Scholar]) showing that the two estimators have comparable finite sample global as well as local behavior.     

Optimal Halton Sequence via Inversive Scrambling

In this article, we develop the Halton sequence of generating quasi-random numbers to an optimal sequence which has the inversive property. The new constructed quasi-random number generator satisfies the extra uniformity condition on [0, 1]. We finally present the performances of this generator in contrast to the former optimal Halton sequence in Chi et al. (2005 Chi, H., Mascagni, M. and Warnock, T. 2005. On the Optimal Halton Sequences. Math. Comput. in Simul., 70(1): 9–21. [Crossref], [Web of Science ®] , [Google Scholar]) and modified optimal Halton sequence in Fathi et al. (2009 Fathi, B., Samimi, H. and Eskandari, A. 2009. A New Efficient Algorithm for Linear Scrambling Halton Sequence. International Journal of Applied Mathematics, 22(7): 1059–1065.  [Google Scholar]).     

Asymptotic Inference for Waiting Times and Patiences in Queues with Abandonment

Motivated by applications in call center management, we propose a framework based on empirical process techniques for inference about waiting time and patience distributions in multiserver queues with abandonment. The framework rigorises heuristics based on survival analysis of independent and identically distributed observations by allowing correlated waiting times. Assuming a regenerative structure of offered waiting times, we establish asymptotic properties of estimators of limiting distribution functions and derived functionals. We discuss construction of bootstrap confidence intervals and statistical tests, including a simple bootstrap two-sample test for comparing patience distributions. A small simulation study and a real data example are presented.     

Bayesian Estimation of the Parameters of Bivariate Exponential Distributions

In this article, we develop an empirical Bayesian approach for the Bayesian estimation of parameters in four bivariate exponential (BVE) distributions. We have opted for gamma distribution as a prior for the parameters of the model in which the hyper parameters have been estimated based on the method of moments and maximum likelihood estimates (MLEs). A simulation study was conducted to compute empirical Bayesian estimates of the parameters and their standard errors. We use moment estimators or MLEs to estimate the hyper parameters of the prior distributions. Furthermore, we compare the posterior mode of parameters obtained by different prior distributions and the Bayesian estimates based on gamma priors are very close to the true values as compared to improper priors. We use MCMC method to obtain the posterior mean and compared the same using the improper priors and the classical estimates, MLEs.     

On Statistical Properties of Palindromes in DNA

The main aim of this article is to determine the distribution of the number of palindromes of a fixed length in a DNA sequence. Palindrome in DNA is a part of the DNA sequence which is equal to its complementary sequence read backwards (C ～ G, A ～ T). We examine the general case where the distribution of the nucleobases is arbitrary. Further, we determine conditions in which Normal approximation can be used. Special attention is given to coding and non-coding regions in DNA and to the distribution of bases in those parts of DNA.     

Circular success and failure runs in a sequence of exchangeable binary trials

Let X₁,…,X_n be an exchangeable sequence of binary trials arranged on a circle with possible values “1” (success) or “0” (failure). In an exchangeable sequence, the joint distribution of X₁,X₂,…,X_n is invariant under the permutation of its arguments. For the circular sequence, general expressions for the joint distributions of run statistics based on the joint distribution of success and failure run lengths are obtained. As a special case, we present our results for Bernoulli trials. The results presented consist of combinatorial terms and therefore provide easier calculations. For illustration purposes, some numerical examples are given and the reliability of the circular combined k-out-of-n:G and consecutive k_c-out-of-n:G system under stress–strength setup is evaluated.