Analysis of a finite‐buffer bulk‐service queue with discrete‐Markovian arrival process: D‐MAP/Ga,b/1/N

Discrete‐time queues with D‐MAP arrival process are more useful in modeling and performance analysis of telecommunication networks based on the ATM environment. This paper analyzes a finite‐buffer discrete‐time queue with general bulk‐service rule, wherein the arrival process is D‐MAP and service times are arbitrarily and independently distributed. The distributions of buffer contents at various epochs (departure, random, and prearrival) have been obtained using imbedded Markov chain and supplementary variable methods. Finally, some performance measures such as loss probability and average delay are discussed. Numerical results are also presented in some cases. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 345–363, 2003.     

A bidirectional heuristic for maximizing the net present value of large‐scale projects subject to limited resources

We consider the scheduling of large‐scale projects to maximize the project net present value given temporal and resource constraints. The net present value objective emphasizes the financial aspects of project management. Temporal constraints between the start times of activities make it possible to handle practical problem assumptions. Scarce resources are an expression of rising cost. Since optimization techniques are not expedient to solve such problems and most heuristic methods known from literature cannot deal with general temporal constraints, we propose a new bidirectional priority‐rule based method. Scheduling activities with positive cash flows as early and activities with negative cash flows as late as possible results in a method which is completed by unscheduling techniques to cope with scarce resources. In a computational experiment, we compare the well‐known serial generation scheme where all activities are scheduled as early as possible with the proposed bidirectional approach. On the basis of a comprehensive data set known from literature containing instances with up to 1002 activities, the efficiency of the new approach is demonstrated. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003     

四阶Fibonacci数列的通项及性质

著名的二阶Fibonacci数列有许多通项表达式和性质.文中运用矩阵方法,对四阶Fibonacci数列进行了比较深入的研究,求得了四阶Fibonacci数列的3个通项表达式,并得到了一些与Fibonacci数列相似的性质.     

广义Fibonacci数列的通项及性质

著名的Fibonacci数列有许多通项表达式和性质。利用数学归纳法和特征方程求根的方法对广义Fibonacci数列Rn 1=uRn vRn-1,R0=a,R1=b进行研究,得到了两个通项表达式和一个性质.     

指控系统总体设计中的车电综合设计

围绕指控系统总体设计中的车电综合设计,描述了车电综合设计的概念。以提高指控系统的一致性、互换性、可维修性和可靠性为目标,提出了相关设计原则。从工程应用和技术实现的角度出发,提出了设计过程中应考虑的方舱布局、供电系统、车辆布线、避雷设计、电连接器选型、线缆选型等多方面的因素及其实现方法。最后,提出了在总体设计前期必须重视车电综合设计的观点。     

人手操作的联体计算

机器人的一个重要理论问题是如何控制机械手以获得所需要的运动。本文将人手操作的基本运动,抽象为具有七个构件而有九个自由度的刚体系统,严格地分析了这些运动,并根据实际情况考虑到各构件的重力、控制力和摩擦阻力,因此能完成人手操作的多种功能。而为了便于在计算机上实施运算利用Kane方程建立了以广义坐标表达的运动微分方程,这可作为分析机械手运动的理论依据。     

基于频率补偿的时延估计方法

由于2个测量站的通道幅相不一致而导致送给时延估计器的两路信号的频率有差异,继而影响时延估计和系统定位精度。首先理论推导了频率差异是如何影响广义相关时延估计的,接着应用频域相关函数对频率差异做准确估计和补偿,最后给出了频差补偿后的时延估计方法。以4种常用通信信号为例,仿真验证了不同信噪比下所提出方法的正确性和有效性。     

Some probability functions in reliability and their applications

There has been much research on the general failure model recently. In the general failure model, when the unit fails at its age t, Type I failure (minor failure) occurs with probability 1 ? p(t) and Type II failure (catastrophic failure) occurs with probability p(t). In the previous research, some specific shapes (constant, non‐decreasing, or bathtub‐shape) on the probability function p(t) are assumed. In this article, general results on some probability functions are obtained and applied to study the shapes of p(t). The results are also applied to determining the optimal inspection and allocation policies in maintenance problems. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

试论公安现役本科院校基础课程改革目标

公安现役本科院校基础课程的改革应当确立一定的目标,这种目标的确立应当以其特定的人才培养目标为依据,坚定不移地围绕基础与特色做文章,并逐步构建基础课程的教育平台。     

Designing acceptance sampling schemes for life testing with mixed censoring

Mixed censoring is useful extension of Type I and Type II censoring and combines some advantages of both types of censoring. This paper proposes a general Bayesian framework for designing a variable acceptance sampling scheme with mixed censoring. A general loss function which includes the sampling cost, the time‐consuming cost, the salvage value, and the decision loss is employed to determine the Bayes risk and the corresponding optimal sampling plan. An explicit expression of the Bayes risk is derived. The new model can easily be adapted to create life testing models for different distributions. Specifically, two commonly used distributions including the exponential distribution and the Weibull distribution are considered with a special decision loss function. We demonstrate that the proposed model is superior to models with Type I or Type II censoring. Numerical examples are reported to illustrate the effectiveness of the method proposed. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004