CONSTRUCTION OF RESOLVABLE ROW-COLUMN DESIGNS BASED ON CONTRACTIONS

This paper defines the contraction of a resolvable row‐column design for more than two replicates. It shows that the (M,S)‐optimality criterion for the row‐column designs can be expressed simply in terms of the elements of the row and column incidence matrices of the contraction. This allows the development of a very fast algorithm to construct optimal or near‐optimal resolvable row‐column designs. The performance of such an algorithm is compared with an existing algorithm.     

Exchange algorithms for constructing large spatial designs

Exchange algorithms are widely used for optimizing design criteria and have proven to be highly effective. However, application of these algorithms can be computationally prohibitive for very large design problems, and in situations for which the design criterion is sufficiently complex so as to prevent efficient evaluation strategies. This paper reports on several modifications to exchange algorithms that lead to large reductions in the computational burden associated with optimizing any given design criterion. A small study indicates that these modifications do not significantly impact the quality of designs, while reductions in effort of over 90% can be achieved.     

Algorithms for the construction of optimizing distributions

We will consider the following problem.Maximise Φ(p)over P={p=(p₁,P₂,…,p_j):P_j≧0,∑p_j=1}". We require to calcute an optimizing distribution. Examples arise in optimal regression design,maximum likelihood estimation and stratified sazmpling problems. A class of multiplicative algorithms, indexed by functions which depend on the derivatives of Φ(·)is considered for solving this problem.Iterations are of the form:p_j ^(r+1)αp_j ^(r)f(x_j ^(r)), where x_{j (r)}=d_j ^(r) or F_j ^(r)and d_j ^(r)=?Φ/?p_j While F_j ^(r)=D_j ^(r)?∑p_i ^(r)d_i ^(r) (a directional derivative)at p=p^(r)f(·)satisfies some suitable properties and may depend on one or more free parameters. These iterations neatly submit to the constraints ofv the problem. Some results will be reported and extensions to problems dependin on two or more distributions and to problems with additional constraints will be considered.     

Bayesian Analysis of the Censored Regression Model with an AEPD Error Term

We present the censored regression model with the error term following the asymmetric exponential power distribution. We propose three Markov chain Monte Carlo (MCMC) algorithms: the first one uses the probability integral transformation; the second one uses a combination of the probability integral transformation and random walk draws; while the third one uses random walk draws. Using simulated data we compare the performance of the three MCMC algorithms. Then we compare the posterior means, or Bayes estimates, with maximum likelihood estimates. We estimate the stock option portion of executive compensation as an example of the empirical application.     

Online control by attributes in the presence of classification errors with variable inspection interval

ABSTRACT

The procedure for online control by attribute consists of inspecting a single item at every m items produced (m ≥ 2). On each inspection, it is determined whether the fraction of the produced conforming items decreased. If the inspected item is classified as non conforming, the productive process is adjusted so that the conforming fraction returns to its original status. A generalization observed in the literature is to consider inspection errors and vary the inspection interval. This study presents an extension of this model by considering that the inspected item can be rated independently r (r ≥ 1) times. The process is adjusted every time the number of conforming classifications is less than a, 1 ≤ a ≤ r. This method uses the properties of an ergodic Markov chain to obtain the expression for the average cost of this control system. The genetic algorithm methodology is used to search for the optimal parameters that minimize the expected cost. The procedure is illustrated by a numerical example.     

"白马非马"与"窜改词义"谬误--从与冯友兰不同的视角批判公孙龙

不少今哲颇褒公孙龙的"白马非马"(P)论题,而冯友兰大师则较为跟随古哲,颇贬P.本文赞同后者.公孙龙说"白马非马"(P),或"懒(不捕鼠的)猫非猫"(Q),人们都把P、R的"非"解作"不是"而不能解作"异于"、"不等于",因语言乃"约定俗成",所以P、Q皆假.至于"鲸鱼非鱼"(R),在"鱼"的词义未被"理性修订"之前,R也是假句.虽然公孙龙从论据正确地建立"白马异于马",但当他再从"异于"推论"白马非马"时,推论明显不正确,犯"窜改词义"谬误.     

A 2-approximation for the preceding-and-crossing structured 2-interval pattern problem

The 2-interval pattern problem over its various models and restrictions was proposed by Vialette (2004) for the application of RNA secondary structure prediction. We present an O(n ³logn)-time 2-approximation algorithm for the problem of finding a largest { < ,-structured subset of 2-intervals given an input 2-interval set of size n. This greatly improves the previous best approximation ratio of 6 by Crochemore et al. (2005).     

基于遗传算法的三级逆向物流网络设计模型研究

建立初始回收点以方便客户、提高回收速度以及建立集中回收中心以负责产品的收回、分拣并统一运送到相应的生产商或分销商修理地点是一种节约、有效的多层次产品回收模式。本文在即存研究基础之上,加入了考虑初始点回收成本、回收产品中再销售品的收益和可再利用品的收益等变量,提出了能够优化连接客户、集中回收中心和生产商三级逆向物流网络数学模型,最后灵敏度分析表明遗传算法对于求解这类问题是一种有效的方法。     

基于遗传算法的生产批量优化问题

针对生产费用、生产准备费用和库存费用综合指标最小的、最优的能力约束生产批量问题,建立基于遗传算法的数学模型,通过模拟试验及实际问题计算,验证算法的可行性。     

Close Approximations of Minimum Rectangular Coverings

We consider the problem of covering arbitrary polygons with rectangles. The rectangles must lie entirely within the polygon. (This requires that the interior angles of the polygon are all greater than or equal to 90 degrees.) We want to cover the polygon with as few rectangles as possible. This problem has an application in fabricating masks for integrated circuits.In this paper we will describe the first polynomial algorithm, guaranteeing an O(log n) approximation factor, provided that the n vertices of the input polygon are given as polynomially bounded integer coordinates. By the same technique we also obtain the first algorithm producing a covering which is within a constant factor of the optimal in exponential time (compared to the doubly-exponential known before).