Sequencing heuristics for dependent setups in a continuous process industry

In this paper we address the scheduling of Biaxially Oriented Polypropylene (BOPP) film production, which belongs to the plastics industry and is a continuous process. Scheduling problems in BOPP film production involve processing different thickness settings of films on a common facility. Customer orders of the same thickness setting are usually grouped together as a production batch and a setup time is incurred whenever the batch is switched. However, there is usually more than one batch for the same thickness setting because of the due date constraints of the orders. Therefore, there is a need to develop a batching and sequencing scheme that minimizes the total setup time, or equivalently the makespan, under the due date constraint. In this paper heuristics are developed to generate a near-optimal solution for the problem. The heuristics are evaluated by an optimal solution procedure and are tested by using the actual data from a plant making the BOPP film. Comparison of the heuristics with the results of the current system has demonstrated a significant reduction in total setup time.     

中国古代田径运动的形成与演变

田径是人类社会活动的产物,在我国历史悠久,源远流长.它随着社会的发展而逐渐演变为当今的田径运动.探寻、研究我国古代有关田径的起源、形成的历史,正如司马迁所说,在于"究天人之际,通古今之变",对于推进发展田径运动,以增进人们的身体健康,具有一定的积极意义.     

从对景写生到对景创作--浅谈现代山水画写生

写生对学习中国山水画有着很重要的作用,从传统写生方法到现代写生方法,山水写生有了很大的变化。现代山水写生包括对景写生和对景创作由低到高的两个阶段。现代山水写生方法与传统的“目识心记,勾其大要”的写生有了明显的区别,它吸收了西方的造型技巧,能准确反映客观形象,同时又进一步继承发展了传统的笔墨表现方法,使写生作品更具生动性、真实感、和时代感,促进了当代山水画的发展。     

中国近代裁撤厘金与当前税费改革比较研究

虽然任何一种税费制度安排都有其客观原因,但若制度方案的选择出现失误,则必然造成弊端丛生,尾大不掉,从而使制度改革陷入困境.厘金制度和农村税费制度因其"不得已"的安排,引发了农民负担加重等不良后果.当前农民税费制度改革要走出"黄宗羲定律"所述的"历史"怪圈,必须进行从政治体制到财政体制全方位的配套改革.     

百年中国儿童文学

中国儿童文学产生于五四时期。百年中国儿童文学的发展 ,以 1 94 9年为界 ,分属两个时代 6个阶段。新世纪的儿童文学发展面临着机遇与挑战 ,百年来的历史经验与教训可以作为今天的借鉴 ,提醒人们因势利导、扬长避短、创造条件、与时俱进     

庄子的实用观:无用之用

庄子把常人所说的有一般效用之物,称作"小用";把引人进入大道、保人享尽天年等具有非常使用价值的东西,称作"大用"。庄子的学说不能帮助世人争权夺利,求名求荣,却能助人修身养性、延年益寿。庄子毕生所倡导的就是要人们追求这种"大用"。庄子在乱世暴政的特定社会条件下提出了无用之用思想。"无用",指无用于暴政。"之用",指保全自身。通过"不材"、"中道"、"与时俱化",为人们设想了一套处乱世的方法。它体现了庄子对人生命存在的热爱和关注,深藏着一个平民知识分子的愤世精神和对劳动人民的同情。无用之用是应付暴君乱世的权宜之计,切不可不分时代地随便搬用。     

试论马克思主义与时俱进的本质特征

马克思主义具有与时俱进的本质特征:从马克思主义的产生过程看,与时俱进是马克思主义形成的主要特征;从马克思主义的内在要求看,与时俱进是马克思主义的本质属性;从马克思主义的发展历程看,与时俱进是马克思主义的必然要求;从马克思主义的历史使命看,与时俱进是马克思主义的永恒主题。     

Maximum Penalized Likelihood Estimation in a Gamma-Frailty Model

The shared frailty models allow for unobserved heterogeneity or for statistical dependence between observed survival data. The most commonly used estimation procedure in frailty models is the EM algorithm, but this approach yields a discrete estimator of the distribution and consequently does not allow direct estimation of the hazard function. We show how maximum penalized likelihood estimation can be applied to nonparametric estimation of a continuous hazard function in a shared gamma-frailty model with right-censored and left-truncated data. We examine the problem of obtaining variance estimators for regression coefficients, the frailty parameter and baseline hazard functions. Some simulations for the proposed estimation procedure are presented. A prospective cohort (Paquid) with grouped survival data serves to illustrate the method which was used to analyze the relationship between environmental factors and the risk of dementia.     

思想家歌德

歌德的思想涵盖了宇宙、人生、社会、政治、文艺以至自然科学等方方面面 ,丰富、博大、深邃而且超前 ;他以诗剧《浮士德》等一系列作品表现的浮士德精神 ,更集中体现了整个西方的精神亦即近代资本主义精神。以歌德第一个提出的“世界文学”的构想为例 ,阐明歌德思想的超前、博大等重要特质。     

“三个代表”重要思想:时代背景下的深刻思考

"三个代表"重要思想是我们党对当今时代的积极回应和深刻思考。与时俱进,是"三个代表"重要思想的时代精神和时代特征的突出体现;科学判断党的历史方位,是认识"三个代表"重要思想时代背景和时代内容的坚实基础;"四个如何认识",是对"三个代表"重要思想的时代背景、时代要求的进一步思考与阐发;忧患意识、历史使命感和执政意识,是"三个代表"重要思想蕴涵的时代意识的具体体现;发展教育、赢得青年,是"三个代表"重要思想对现代教育事业提出的时代要求。