Note: Minimizing the variability of the waiting times in a globally gated elevator polling system

A polling system comprising n queues and a single server is considered. Service is performed according to an elevator scheme under the globally gated regime. The problem of arranging the channels to minimize a measure of the variability of the waiting times is addressed. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 605–611, 1997     

冗余捷联惯组信息容错管理算法

对于单机多表斜置冗余捷联惯组的故障诊断、隔离和重构,提出无迹卡尔曼滤波结合三交叉容错融合方法。考虑各误差项,对不同的冗余配置建立统一数学模型。通过三交叉重构模型的设计可快速隔离一度故障并输出正确结果,对被隔离的故障表各误差系数采用无迹卡尔曼滤波方法标定,可辨识因误差系数改变而引起的软故障。以单机五陀螺的两种误差系数软故障为例仿真验证了冗余捷联惯组信息容错管理算法的正确性。     

聚铝碳硅烷的流变性和纺丝性研究

采用单孔纺丝装置对不同铝含量的聚铝碳硅烷(PACS)的流变性和流变性进行研究.结果表明:随着温度升高,PACS熔体的流体特性逐渐接近牛顿流体;PACS熔体粘度对温度有强烈的依赖性,其软化点在190℃～220℃范围时,其粘流活化能在190～260kJ/mol之间;当PACS的粘度在100Pa·s左右时可纺性好;铝含量对PACS的流变性能和可纺性有重要的影响,随着铝含量的增加,PACS熔体的粘度增大,因而PACS的纺丝温度更高,可纺性变差.     

一款0.18μm CMOS辐射加固差分压控振荡器

基于对称负载压控振荡器(VCO)的单粒子瞬变(SET)失效机理,应用设计加固(RHBD)技术分别改进了偏置电路和环形振荡器,设计和实现了一款0.18μm CMOS辐射加固差分VCO.模拟结果表明:加固VCO的SET敏感性大幅降低,同时还降低了抖动对于电源噪声的敏感性.虽然电路结构变化会导致频率下降,但可以通过调整电路尺寸而解决.此外,加固VCO面积开销有所降低,优于其他加固方法.     

基于Petri网的指挥控制系统仿真

指挥控制系统是一个具有分布、并发、异步等特性的复杂系统,Petri网是描述具有此类特征系统的有效工具.提出了基于Petri网的指挥控制系统仿真平台的具体设计方案.介绍了仿真平台的实现方法和程序的设计思路,实现了对普通Petri网、X1系统的建模,进行了功能和结构上的分析,并对分析结果的现实意义作了进一步的讨论.     

Influence of active constrained layer damping on the coupled vibration response of functionally graded magneto-electro-elastic plates with skewed edges

This article makes the first attempt in assessing the influence of active constrained layer damping (ACLD) treatment towards precise control of frequency responses of functionally graded skew-magneto-electro-elastic (FGSMEE) plates by employing finite element methods. The materials are functionally graded across the thickness of the plate in terms of modest power-law distributions. The principal equations of motion of FGSMEE are derived via Hamilton’s principle and solved using condensation technique. The effect of ACLD patches are modelled by following the complex modulus approach (CMA). Additionally, distinctive emphasis is laid to evaluate the influence of geometrical skewness on the attenuation capabilities of the plate. The accuracy of the current analysis is corroborated with comparison of previous researches of similar kind. Additionally, a complete parametric study is directed to understand the combined impacts of various factors like coupling fields, patch location, fiber orientation of piezoelectric patch in association with skew angle and power-law index.     

当代俄罗斯电子战产品主要研制单位及装备发展综述

作为现代战场的核心内容之一,无线电电子战产品已成为近几十年来发展异常迅速的一类军事装备。俄罗斯的军事装备历经车臣战争、俄格冲突、叙利亚战争和俄乌冲突等众多实战检验并不断得到完善,正逐渐展现出强大的军事威慑力,而电子战设备就是俄罗斯重点发展且成效显著的“不对称”战力方向之一。西方专家普遍认为电子战系统是俄军最危险的武器装备之一,可见其水平已属国际领先水平。本文介绍了当代俄罗斯对无线电电子战内容的理解、俄罗斯电子战产品的主要研制单位和发展现状,重点分析了俄罗斯近30年来最知名的陆、海、空电子战装备的分类、组成、指标和功能等,对俄罗斯电子战未来的技术发展趋势进行了预测,以期为国内电子战装备和技术发展提供借鉴。     

MABAC method for multiple attribute group decision making under q-rung orthopair fuzzy environment

As the generalization of intuitionistic fuzzy set (IFS) and Pythagorean fuzzy set (PFS), the q-rung orthopair fuzzy set (q-ROFS) has emerged as a more meaningful and effective tool to solve multiple attribute group decision making (MAGDM) problems in management and scientific domains. The MABAC (multi-attributive border approximation area comparison) model, which handles the complex and uncertain decision making issues by computing the distance between each alternative and the bored approximation area (BAA), has been investigated by an increasing number of researchers more recent years. In our article, consider the conventional MABAC model and some fundamental theories of q-rung orthopair fuzzy set (q-ROFS), we shall introduce the q-rung orthopair fuzzy MABAC model to solve MADM problems. at first, we briefly review some basic theories related to q-ROFS and conventional MABAC model. Furthermore, the q-rung orthopair fuzzy MABAC model is built and the decision making steps are described. In the end, An actual MADM application has been given to testify this new model and some comparisons between this novel MABAC model and two q-ROFNs aggregation operators are provided to further demonstrate the merits of the q-rung orthopair fuzzy MABAC model.     

Exact analysis of (R,s, S) inventory control systems with lost sales and zero lead time

We study an (R, s, S) inventory control policy with stochastic demand, lost sales, zero lead‐time and a target service level to be satisfied. The system is modeled as a discrete time Markov chain for which we present a novel approach to derive exact closed‐form solutions for the limiting distribution of the on‐hand inventory level at the end of a review period, given the reorder level (s) and order‐up‐to level (S). We then establish a relationship between the limiting distributions for adjacent values of the reorder point that is used in an efficient recursive algorithm to determine the optimal parameter values of the (R, s, S) replenishment policy. The algorithm is easy to implement and entails less effort than solving the steady‐state equations for the corresponding Markov model. Point‐of‐use hospital inventory systems share the essential characteristics of the inventory system we model, and a case study using real data from such a system shows that with our approach, optimal policies with significant savings in inventory management effort are easily obtained for a large family of items.     

The effects of information on a queue with balking and phase‐type service times

This article generalizes the models in Guo and Zipkin, who focus on exponential service times, to systems with phase‐type service times. Each arriving customer decides whether to stay or balk based on his expected waiting cost, conditional on the information provided. We show how to compute the throughput and customers' average utility in each case. We then obtain some analytical and numerical results to assess the effect of more or less information. We also show that service‐time variability degrades the system's performance. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008