Prediction of the twisting moment and axial force in a circular rubber cylinder for combined extension and torsion based on the logarithmic strain approach

The scope of the present work is the application of a particular class of strain energy function, based on the logarithmic strain, for the prediction of the twisting moment and axial force of a rubber circular cylinder under combined extension and torsion. The strain energy function involves four material parameters three of which are determined by fitting published experimental data from simple tensile and compression tests of natural rubber. One of the parameters of the proposed model has physical meaning, and it is equal to one ninth of the initial modulus of elasticity of the material. Hence, the number of unknown parameters is reduced to three. The logarithmic strain energy function is then applied to a combined extension and torsion problem of a rubber circular cylinder to check its performance for more complicated deformations. The results are compared with corresponding experimental and theoretical solutions available in the literature to validate the proposed model. It is found that the proposed strain energy function apart from predicting the common modes of deformations is also capable to determine more complicated types of deformation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

SARS流行预测分析

表面上突如其来的SARS本质上却有极规律的内在发展演化机制，遵从初始缓慢增长、加速、减速和稳定终止四个阶段总体道路，自然和社会生活领域众多事件演化都符合这一规律，因而可以运用广义的Logistic生长模型进行描述。基于先期流行的广东SARS感染病例数据，以及尚未结束的北京、全国2003年SARS流行统计数据，借助于最优化分析技术，运用广义的Logistic生长模型对该事件演化特征参量进行了辨识；在此基础上，又借助于广义生长模型的特例——Gompertz函数进行了演化过程的预测，并与其他生长模型结果进行了比较。研究表明，生长模型模拟结果均与实际数据有很好的一致性，可以用来预测事件的发生演化过程，此次SARS事件堪称生长模型的经典实例。     

多层砖砌体房屋震害分析及抗震措施

介绍了我国砖砌体房屋历年来遭受震害的程度以及砖砌体的抗震性能，针对一些震害现象，分别从建筑布置和抗震措施加强对砖砌体的抗震性能进行论述。     

矿井串联系统模糊可靠性理论的研究

矿井系统不仅具有随机性，而且同时也具有模糊性，在系统分析与设计过程中应同时考虑这两种不确定性因素的影响。文中提出了模糊故障、模糊功能、系统模糊运营状态和广义可靠度等概念，并在此基础上提出了求单元及串联系统的生产能力、营运费用、应急维修费用、修理时间和广义可靠度等指标的方法，建立了使系统平均生产能力最大的系统最优运营策略的数学模型。     

Homogeneous Lyapunov function for homogeneous continuous vector field

The goal of this article is to provide a construction of a homogeneous Lyapunov function associated with a system of differential equations , under the hypotheses: (1) vanishes at x = 0 and is homogeneous; (2) the zero solution of this system is locally asymptotically stable. Moreover, the Lyapunov function tends to infinity with x, and belongs to , with as large as wanted. As application to the theory of homogeneous systems, we present two well known results of robustness, in a slightly extended form, and with simpler proofs.     

模糊综合评判方法在碳酸盐岩油气勘探中的应用

详细地阐述了模糊综合评判方法的数学原理及其在油气勘探开发中的应用.根据某油田的生产层参数资料,运用MICROSOFT EXCEL软件,在对各参数进行统计研究并了解它们分布规律的基础上,合理地构造出一系列隶属函数,通过编制相应的计算机程序,完成综合评判.评判结果与勘探实际吻合较好.该方法有效地适用于碳酸盐岩油气藏的勘探开发.     

Search for the upper bound of Bayesian estimates of the parameter in an exponential failure model with two known quantiles of an a priori distribution function

A fast exact algorithm of searching for the upper bound of Bayesian estimates for the parameter of the exponential distribution under the condition that an a priori distribution belongs to the class of all distribution functions with two equal quantiles. This problem arises in analyzing the sensitivity of Bayesian estimates to the choice of an a priori distribution in an exponential failure model. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 90–102, January–February 2007.     

Binary rewriting and call interception for efficient runtime protection against buffer overflows

Buffer overflow vulnerabilities are one of the most commonly and widely exploited security vulnerabilities in programs. Most existing solutions for avoiding buffer overflows are either inadequate, inefficient or incompatible with existing code. In this paper, we present a novel approach for transparent and efficient runtime protection against buffer overflows. The approach is implemented by two tools: Type Information Extractor and Depositor (TIED) and LibsafePlus. TIED is first used on a binary executable or shared library file to extract type information from the debugging information inserted in the file by the compiler and reinsert it in the file as a data structure available at runtime. LibsafePlus is a shared library that is preloaded when the program is run. LibsafePlus intercepts unsafe C library calls such as strcpy and uses the type information made available by TIED at runtime to determine whether it would be ‘safe’ to carry out the operation. With our simple design we are able to protect most applications with a performance overhead of less than 10%. Copyright © 2006 John Wiley & Sons, Ltd.     

Distributed architecture for energy management D-structure

Electric power systems are expanding in size and complexity, and the requirement for the energy management system (EMS) is becoming more important. In this computer control system, a single control computer is used mainly as the primary computer and its software is very complicated because of its hugh number of small, quick tasks to obtain high response speed. Therefore, much effort is needed to develop and modify the programs, and the responsiveness of this centralized architecture varies greatly when many faults occur in the power system. This paper describes a new distributed architecture for the EMS. Distributed processors execute the functions cooperatively with periodic access to the common bulletin board database in which information about the power system exist. This architecture facilitates the software development and maintenance, and it also enhances the performance by the parallel processing of the distributed functions.     

试验模态分析技术的进展

本文对试验模态分析技术的进展,特别是80年代发展起来的有关新技术进行了综合评述。主要内容有:试验激振技术、频响函数估计方法、试验测试设备、以及各种模态识别方法,包括单输入/多输出和多输入/多输出识别的时域和频域方法。文中强调了试验模态分析技术各环节之间的相互联系、相互影响,对于80年代已成为模态识别主流的多输入/多输出各种方法(包括作者发展的几种方法),用统一方法作了描述。最后提出了若干值得进一步研究的方向。