龙榆生创办《词学季刊》的宗旨与举措

现代词学家龙榆生创办《词学季刊》,将其定位成以词学研究为主的专业性期刊,在确定作者人选范围、确立与读者取得沟通方式的编辑思想主导下,推出＂创刊号＂,实现他的编辑意旨;而后着力搞好编辑与作者间的协作,以利于期刊的持续发展;为读者着想,争取读者参与到期刊编辑工作中来。《词学季刊》的出版,为词学研究期刊编辑史上留下了风采的一笔。     

元器件性能退化信息的系统性能可靠性评估

性能可靠性方法为解决现代工程实际中的高可靠、长寿命、小子样产品的可靠性建模分析提供了途径.目前的性能可靠性研究主要是针对元器件开展的,对系统性能可靠性进行研究时通常需要将其看作一个元器件,需要得到系统的性能退化数据,在某些情况下,得到系统的性能退化数据比较困难.实际上,由于元器件的性能退化导致系统性能的变化,因而可以利...     

A novel formulation of material nonlinear analysis in structural mechanics

This article demonstrates a novel approach for material nonlinear analysis. This analysis procedure eliminates tedious and lengthy step by step incremental and then iterative procedure adopted classically and gives direct results in the linear as well as in nonlinear range of the material behavior. Use of elastic moduli is eliminated. Instead, stress and strain functions are used as the material input in the analysis procedure. These stress and strain functions are directly derived from the stress-strain behavior of the material by the method of curve fitting. This way, the whole stress-strain diagram is utilized in the analysis which naturally exposes the response of structure when loading is in nonlinear range of the material behavior. It is found that it is an excellent computational procedure adopted so far for material nonlinear analysis which gives very accurate results, easy to adopt and simple in calculations. The method eliminates all types of linearity assumptions in basic derivations of equations and hence, eliminates all types of possibility of errors in the analysis procedure as well. As it is required to know stress distribution in the structural body by proper modelling and structural idealization, the proposed analysis approach can be regarded as stress-based analysis procedure. Basic problems such as uniaxial problem, beam bending, and torsion problems are solved. It is found that approach is very suitable for solving the problems of fracture mechanics. Energy release rate for plate with center crack and double cantilever beam specimen is also evaluated. The approach solves the fracture problem with relative ease in strength of material style calculations. For all problems, results are compared with the classical displacement-based liner theory.     

Replicated batch means for steady‐state simulations

This paper studies a new steady‐state simulation output analysis method called replicated batch means in which a small number of replications are conducted and the observations in these replications are grouped into batches. This paper also introduces and compares methods for selecting the initial state of each replication. More specifically, we show that confidence intervals constructed by the replicated batch means method are valid for large batch sizes and derive expressions for the expected values and variances of the steady‐state mean and variance estimators for stationary processes and large sample sizes. We then use these expressions, analytical examples, and numerical experiments to compare the replicated batch means method with the standard batch means and multiple replications methods. The numerical results, which are obtained from an AR(1) process and a small, nearly‐decomposable Markov chain, show that the multiple replications method often gives confidence intervals with poorer coverage than the standard and replicated batch means methods and that the replicated batch means method, implemented with good choices of initialization method and number of replications, provides confidence interval coverages that range from being comparable with to being noticeably better than coverages obtained by the standard batch means method. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

概念模型验证方法研究综述

概念模型验证是保证和提高仿真可信性的重要手段,是建模与仿真VV＆A中的重点和难点．首先将概念模型的验证方法划分为非形式化方法、静态方法、动态方法和形式化方法4类,并提出了一种基于本体推理的概念模型验证方法,然后对各种方法的基本思想、基本原理、基本过程、适用对象、优缺点进行全面的分析总结,明确了各种方法的优缺点和适用范围,为如何选用各种验证方法提供参考,也明确了下一步应重点研究的问题．     

Nonparametric bayesian lifetime data analysis using dirichlet process lognormal mixture model

We propose a nonparametric Bayesian lifetime data analysis method using the Dirichlet process mixture model with a lognormal kernel. A simulation‐based algorithm that implements the Gibbs sampling is developed to fit the Dirichlet process lognormal mixture (DPLNM) model using rightly censored failure time data. Five examples are used to illustrate the proposed method, and the DPLNM model is compared to the Dirichlet process Weibull mixture (DPWM) model. Results indicate that the DPLNM model is capable of estimating different lifetime distributions. The DPLNM model outperforms the DPWM model in all the examples, and the DPLNM model shows promising potential to be applied to analyze failure time data when an appropriate parametric model for the data cannot be specified. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

目标毁伤效果评估技术研究进展

目标毁伤效果评估作为目标保障的一项重要内容,对精确打击作战情报保障起到了核心作用,是现代精确打击体系的一个重要环节和关键步骤。文章从评估方法、评估模型和评估系统三个方面入手,梳理了国内外目标毁伤效果评估技术的最新研究进展,并对目前各类评估方法、模型及系统的优缺点分别进行了评述。最后,指出了该领域今后的研究方向。     

Analysis of a machine repair problem with an unreliable server and phase type repairs and services

In this paper we study a machine repair problem in which a single unreliable server maintains N identical machines. The breakdown times of the machines are assumed to follow an exponential distribution. The server is subject to failure and the failure times are exponentially distributed. The repair times of the machine and the service times of the repairman are assumed to be of phase type. Using matrix‐analytic methods, we perform steady state analysis of this model. The time spent by a failed machine in service and the total time in the repair facility are shown to be of phase type. Several performance measures are evaluated. An optimization problem to determine the number of machines to be assigned to the server that will maximize the expected total profit per unit time is discussed. An illustrative numerical example is presented. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 462–480, 2003     

基于扩展标记变迁模型的时钟同步协议正确性验证

时钟同步协议是时间触发网络的一个重要组成部分，是时间触发网络实时性和确定性的关键。本文基于扩展标记变迁模型对时钟同步协议进行建模，基于模型检测方法对协议是否满足正确性属性进行验证。验证结果证明了在不同启动场景下时钟同步网络协议的正确性，也表明了扩展标记变迁模型对于协议验证的有效性。     

防火涂料性能要求及测试方法探讨

介绍了饰面型防火涂料、电缆防火涂料、钢结构防火涂料以及混凝土防火涂料的理化性能要求及防火性能要求。重点阐述了这些防火涂料防火性能的测试方法。