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231.
We consider a stochastic counterpart of the well-known earliness-tardiness scheduling problem with a common due date, in which n stochastic jobs are to be processed on a single machine. The processing times of the jobs are independent and normally distributed random variables with known means and known variances that are proportional to the means. The due dates of the jobs are random variables following a common probability distribution. The objective is to minimize the expectation of a weighted combination of the earliness penalty, the tardiness penalty, and the flow-time penalty. One of our main results is that an optimal sequence for the problem must be V-shaped with respect to the mean processing times. Other characterizations of the optimal solution are also established. Two algorithms are proposed, which can generate optimal or near-optimal solutions in pseudopolynomial time. The proposed algorithms are also extended to problems where processing times do not satisfy the assumption in the model above, and are evaluated when processing times follow different probability distributions, including general normal (without the proportional relation between variances and means), uniform, Laplace, and exponential. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44, 531–557, 1997. 相似文献
232.
热得快火灾危险性分析及火因鉴别方法的研究 总被引:2,自引:0,他引:2
本文以热得快火灾模拟试验为基础,结合其结构特点和实际火灾案例,分析了热得快火灾的形成原因,着重对如何鉴别热得快火灾残留物进行研究,归纳总结出根据热得快火灾残留物进行火灾原因鉴别的判定依据,建立了热得快火灾原因的鉴别方法,并提出了热得快火灾的预防措施。 相似文献
233.
We study stochastic clearing systems with a discrete-time Markovian input process, and an output mechanism that intermittently and instantaneously clears the system partially or completely. The decision to clear the system depends on both quantities and delays of outstanding inputs. Clearing the system incurs a fixed cost, and outstanding inputs are charged a delay penalty, which is a general increasing function of the quantities and delays of individual inputs. By recording the quantities and delays of outstanding inputs in a sequence, we model the clearing system as a tree-structured Markov decision process over both a finite and infinite horizon. We show that the optimal clearing policies, under realistic conditions, are of the on-off type or the threshold type. Based on the characterization of the optimal policies, we develop efficient algorithms to compute parameters of the optimal policies for such complex clearing systems for the first time. We conduct a numerical analysis on the impact of the nonlinear delay penalty cost function, the comparison of the optimal policy and the classical hybrid policy (ie, quantity and age thresholds), and the impact of the state of the input process. Our experiments demonstrate that (a) the classical linear approximation of the cost function can lead to significant performance differences; (b) the classical hybrid policy may perform poorly (as compared to the optimal policies); and (c) the consideration of the state of the input process makes significant improvement in system performance. 相似文献
235.
CHENG Hong 《国防科技》2018,39(1):001-004
坚持向科技创新要战斗力,落实到国防动员建设领域,就是要紧紧围绕党在新形势下的强军目标,积极适应现代战争形态新变化、世界军事变革新趋势、总体国家安全新要求和军队使命任务新拓展,加强高技术力量平战一体国防动员,搭建起高技术力量在经济与军事、地方与军队、潜力与实力、平时与战时的桥梁和纽带,全面提升国防动员战时应战、急时应急、平时服务能力,为保障军队能打仗、打胜仗提供强大科技支撑。 相似文献
236.
237.
应用色谱/质谱联用技术对提取93#汽油燃烧烟尘及残留物特征组分的五种萃取剂进行了对比研究。在确保制样过程中汽油组分提取量尽可能一致性的条件下,以提取出的有机特征组分的种类和相对峰面积为标准,利用总离子流色谱图和质量色谱图定性分析了五种萃取剂的萃取效果。 相似文献
238.
239.
在军队油料消耗预测中以直线趋势外推预测法、季节指数预测法和灰色预测法构成组合预测模型,以此为基础引入层次分析法来确定各自权重,按各项预测的重要程度求出组合预测结果。组合预测结果精度较高,并且通过对该组合预测模型中的判断矩阵灵活调整,从而可得到一组适合对应单位的油料消耗组合预测权系数,具有良好通用性,在部队中具有较好的推广价值。 相似文献
240.