Single machine scheduling with a restricted rate‐modifying activity

In this paper we consider the problem of scheduling a set of jobs on a single machine on which a rate‐modifying activity may be performed. The rate‐modifying activity is an activity that changes the production rate of the machine. So the processing time of a job is a variable, which depends on whether it is scheduled before or after the rate‐modifying activity. We assume that the rate‐modifying activity can take place only at certain predetermined time points, which is a constrained case of a similar problem discussed in the literature. The decisions under consideration are whether and when to schedule the rate‐modifying activity, and how to sequence the jobs in order to minimize some objectives. We study the problems of minimizing makespan and total completion time. We first analyze the computational complexity of both problems for most of the possible versions. The analysis shows that the problems are NP‐hard even for some special cases. Furthermore, for the NP‐hard cases of the makespan problem, we present a pseudo‐polynomial time optimal algorithm and a fully polynomial time approximation scheme. For the total completion time problem, we provide a pseudo‐polynomial time optimal algorithm for the case with agreeable modifying rates. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005     

Probabilistic analysis of an asymptotically optimal solution for the completion time variance problem

Scheduling a set of n jobs on a single machine so as to minimize the completion time variance is a well‐known NP‐hard problem. In this paper, we propose a sequence, which can be constructed in O(n log n) time, as a solution for the problem. Our primary concern is to establish the asymptotical optimality of the sequence within the framework of probabilistic analysis. Our main result is that, when the processing times are randomly and independently drawn from the same uniform distribution, the sequence is asymptotically optimal in the sense that its relative error converges to zero in probability as n increases. Other theoretical results are also derived, including: (i) When the processing times follow a symmetric structure, the problem has 2^{⌊(n−1)/2⌋} optimal sequences, which include our proposed sequence and other heuristic sequences suggested in the literature; and (ii) when these 2^{⌊(n−1)/2⌋} sequences are used as approximate solutions for a general problem, our proposed sequence yields the best approximation (in an average sense) while another sequence, which is commonly believed to be a good approximation in the literature, is interestingly the worst. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 373–398, 1999     

深入学习实践科学发展观:中国新一轮发展的强大推动力——学习胡锦涛总书记9月19日重要讲话

认真学习胡锦涛总书记9月19日重要讲话精神,切实搞好深入学习实践科学发展观活动,是推动中国新一轮发展的强大动力。通过深入学习实践科学发展观活动,提高全党的思想理论水平,为推动科学发展提供强大思想动力;努力解决群众反映强烈、影响和制约科学发展的突出问题,为推动科学发展提供强大社会合力;构建有利于科学发展的体制机制,为推动科学发展提供制度保证;提高党的执政能力,为推动科学发展提供坚强组织保证;努力在改进作风上取得新成效,为推动科学发展提供更和谐的环境。     

谈《林教头风雪山神庙》中关于“风雪”、“酒”、“火”的描写

<正>《林教头风雪山神庙》(见高中语文第四册)的“风雪”描写向来为人称道,其中关于“酒”的细节描写,却为人所忽视;至于“火”的描写,论者虽不少,但也只是在分析情节时一笔带过.笔者认为,“酒”、“火”同“风雪”一样,都是施耐庵苦心经营且独具匠心的象征物.本文试略作分析,以祈向同行请教.     

任意信号FFT频谱显示误差及消除方法

分析了任意信号FFT、变换频谱在计算机显示中产生误差的原因,介绍了频率轴坐标标定和显示引起的误差对高精度频谱图的影响,指出了无误差显示应满足的条件,并给出了相应的无误差频谱显示程序。     

变窗长秩排序统计滤波器与噪声图象滤波

基于信号分解理论,在非线性秩排序统计滤波器基础上,提出一种新型的非线性滤波器结构——二值秩排序统计滤波器。主要工作包括:(1)提出了滤波器的定义和实现结构;(2)实现算法;(3)滤波特性分析;(4)噪声图象滤波的计算机仿真。理论分析和实验结果表明,本文提出的滤波器具有良好的脉冲干扰抑制能力和边缘保持特性,硬件实现简单。     

不对称再入弹头滚动共振特性的研究

本文研究不对称再入弹头滚动共振特性。将运动方程、建立在不随弹头慢旋的坐标系上,利用线性化方法进行近似研究。研究了不对称弹头由于慢旋对滚动共振的影响,给出避免发生滚动共振的慢旋角速度公式,并研究了当慢旋角速度较小时,慢旋引起的可能发生持续滚动共振区域的变化。     

关于课程评估模式和原则

通过对典型的教育评估模式的探讨,论述了课程评估的概念、地位和作用,提出了包括确定评估模式,建立指标体系,实施评估在内的全部课程评估工作应遵循的原则,在综合性评估模式中加入了课程制定评估,使评估模式更趋于完整、科学、合理。     

火炮射击精度的灰色系统预测

本文应用灰色系统预测的理论与方法,建立了射击精度的子系统与系统的预测模型,为从微观、宏观上控制误差,提高射击效果,提出了一种科学的预测方法。     

区域掩护高射炮最佳配置的数量分析

本文根据军事运筹学的有关理论,以现装备的高射炮作为主要的防空武器,针对实施区域掩护时为取得良好的掩护效果,从数量上对兵力兵器作了系统分析。