Optimal (τ, T) opportunistic maintenance of a k‐out‐of‐n:G system with imperfect PM and partial failure

The opportunistic maintenance of a k‐out‐of‐n:G system with imperfect preventive maintenance (PM) is studied in this paper, where partial failure is allowed. In many applications, the optimal maintenance actions for one component often depend on the states of the other components and system reliability requirements. Two new (τ, T) opportunistic maintenance models with the consideration of reliability requirements are proposed. In these two models, only minimal repairs are performed on failed components before time τ and the corrective maintenance (CM) of all failed components are combined with PM of all functioning but deteriorated components after τ; if the system survives to time T without perfect maintenance, it will be subject to PM at time T. Considering maintenance time, asymptotic system cost rate and availability are derived. The results obtained generalize and unify some previous research in this area. Application to aircraft engine maintenance is presented. © 2000 John Wiley & Sons;, Inc. Naval Research Logistics 47: 223–239, 2000     

Computational analysis of MMAP[K]/PH[K]/1 queues with a mixed FCFS and LCFS service discipline

This paper studies a queueing system with a Markov arrival process with marked arrivals and PH‐distribution service times for each type of customer. Customers (regardless of their types) are served on a mixed first‐come‐first‐served (FCFS) and last‐come‐first‐served (LCFS) nonpreemptive basis. That is, when the queue length is N (a positive integer) or less, customers are served on an FCFS basis; otherwise, customers are served on an LCFS basis. The focus is on the stationary distribution of queue strings, busy periods, and waiting times of individual types of customers. A computational approach is developed for computing the stationary distribution of queue strings, the mean of busy period, and the means and variances of waiting times. The relationship between these performance measures and the threshold number N is analyzed in depth numerically. It is found that the variance of the virtual (actual) waiting time of an arbitrary customer can be reduced by increasing N. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 399–421, 2000     

Applying a bootstrap approach for setting reorder points in military supply systems

This paper develops and applies a nonparametric bootstrap methodology for setting inventory reorder points and a simple inequality for identifying existing reorder points that are unreasonably high. We demonstrate that an empirically based bootstrap method is both feasible and calculable for large inventories by applying it to the 1st Marine Expeditionary Force General Account, an inventory consisting of $20–30 million of stock for 10–20,000 different types of items. Further, we show that the bootstrap methodology works significantly better than the existing methodology based on mean days of supply. In fact, we demonstrate performance equivalent to the existing system with a reduced inventory at one‐half to one‐third the cost; conversely, we demonstrate significant improvement in fill rates and other inventory performance measures for an inventory of the same cost. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 459–478, 2000     

涉外型院校实施体育“双语教学”的可行性研究

在社会飞速发展的时代,经济的进步促使知识的日新月异,导致教学模式的不断创新。伴随着我国加入WTO,双语教学应运而生.在体育教学中运用双语教学,是体育教学模式的大胆尝试和教学手段的创新.涉外型院校具有实施体育双语教学得天独厚的条件,双语教学的实施具有重要意义,并有可行性。     

利用数形结合方法求解几类代数问题

数学研究的对象是现实世界的数量关系(数)和空间形式(形)。“数”和“形”常按照一定的条件相互转化。数形结合思想是数学的重要的思想方法之一,并蕴于数学基础知识和基本技能之中,在数学解题中应用十分广泛。其实质是将抽象的数学语言与直观图形结合起来,发挥“数”与“形”两种信息的转化及其优势互补与整合,使逻辑思维与形象思维完美统一起来。对于培养学生的创新意识和创造思维具有积极的促进作用。     

少数民族地区汉语教学面临的问题及对策

这里所说的汉语教学是指少数民族地区对民族班学生所进行的第二语言教学。进行汉语教学,不仅要了解学生的汉语基础,了解母语对汉语学习的负面影响,也要准确把握汉语课的性质,优化汉语学习环境,处理好教学总体目标与具体教学目标之间的关系,并采取符合实际需要的教材和教学方法。     

高等学校办学定位探究

办学定位是高等学校确定发展方向、配置资源、形成特色的基本依据,关系到办学的兴衰成败和人才的培养质量,办学定位包含办学目标定位、办学类型定位、办学水平定位、学科性质定位、人才培养定位、办学规模定位、办学特色定位、服务面向定位等内容,高等学校要从社会需求和自身实际出发,切实把握办学定位的原则,科学合理地确定办学定位。     

论军队院校科研管理资源配置机制建设

分析了目前军队院校科研管理资源配置机制中存在的问题及原因,提出了军队院校建立科学高效优化合理的科研管理资源配置机制的基本思路:建立基于学科的资源优化配置机制;建立和完善资源开放平台和共享机制;建立尊重和适应市场规律、科学合理的人才资源配置机制。     

军队律师若干问题研究

军队律师,是专门为其所在部队、部队官兵及军属提供法律服务,保障依法治军的专业法律工作者,具有军人和律师的双重身份。建立和完善军队律师制度,不仅是完善我国律师制度体系的内在要求,也是依法治军,建设社会主义法治国家的必然要求。     

谐音文化的语用价值

谐音不仅是一种独特的语音现象和重要的表达手段,与汉民族特定的文化心理相结合,它还传递着重要的文化信息,蕴含着丰富的语用价值。从社会语言学的角度,探索了谐音文化的语用价值。