CORBA安全综述

1 CORBA规范特点公共对象请求代理结构CORBA是对象管理组OMG在其对象管理结构OMA框架之下以对象请求代理ORB为核心制定的分布式对象处理标准,它定义了对象之间通过ORB透明地发送请求接收响应的机制,保证在分布异构环境下对象之间的互操作性。OMG是一个拥有800多个成员(包括IBM、HP、SUN、DEC等)的国际性组织。OMA参考模型结构如图1所     

基于CHECK方式的联锁仿真系统的设计与实现

针对城市轨道交通包括地铁、轻轨等的过渡信号系统的特点,研制了CHECK方式的列车运行控制系统1。文章在分析基于CHECK方式的联锁与闭塞系统的工作原理的基础上,给出了联锁仿真系统的数学模型,提出了用“事件调度法”这一仿真技术实现CHECK方式的联锁系统的仿真,并予以实现,满足了实际应用的需要。     

一种基于信标控制的安全通信机制及其应用

提出了一种以信标控制为基础、基于 ＴＣＰ／ＩＰ协议的、用于 Ｉｎｔｅｒｎｅｔ上证券交易的安全通信机制,可以实现保密与认证,具有防伪造、防重放、防抵赖功能。     

一种分布式网络指纹识别系统

文章介绍了一种分布式网络指纹识别系统NBFIS(Network-BasedFingerprintIdentifyingSystem)。首先提出模型框架,并对其关键技术特别是指纹图像处理技术及面向对象的数据库技术进行讨论。实现了NBFIS系统的原型并给出实验和性能测试结果。     

Optimal Average Case Estimation in Hilbert Norms

In contrast to the worst case approach, the average case setting provides less conservative insight into the quality of estimation algorithms. In this paper we consider two local average case error measures of algorithms based on noisy information, in Hilbert norms in the problem element and information spaces. We define the optimal algorithm and provide formulas for its two local errors, which explicitly exhibit the influence of factors such as information, information (measurement) errors, norms in the considered spaces, a subset where approximations are allowed, and “unmodeled dynamics.” Based on the error expression, we formulate in algebraic language the problem of selecting the optimal approximating subspace. The solution is given along with the specific formula for the error, which depends on the eigenvalues of a certain matrix defined by information and norms under consideration. Date received: November 25, 1999. Date revised: May 30, 2000.     

基于.net的安全性验证

采用自定义主体Principal和身份Identity实现基于窗体的安全验证,构建了一个灵活方便的安全权限管理系统,综合使用了数据库技术、面向对象设计技术、操作系统权限管理、NET框架中基于代码访问安全性和基于角色访问安全性等多方面技术。该方案可以用于多数WEB系统中,作为通用的安全权限管理模块。     

一种灵活的RFID事件规则管理框架*

射频识别（Radio Frequency Identification,RFID）技术的快速发展,使RFID中间件已经成为业界关注的焦点。初步探讨了RFID中间件中事件规则管理的内容,并提出一种灵活的RFID事件规则管理框架,全面介绍了RFID事件编码、模式过滤、目标事件识别以及业务规则定义四个环节的内容,重点阐述了一种基于XML语言的业务规则定义方法及其执行引擎的底层实现,从而为构建更加具有个性化和扩展能力的RFID应用奠定了基础。     

Identification and control of open-loop unstable processes by relay methods

This paper describes a reliable automatic PID tuning method for open-loop unstable processes. Identification with low order models is performed by means of two relay tests, one with an additional delay, which does not require a priori knowledge about the process, with the only necessary condition being that the process be gain stabilisable. This paper provides an overview of the method, states conditions that need to be satisfied for its successful implementation, and demonstrates its application on a number of examples.     

暂态能量校正和临界群识别：三论暂态能量函数直接法

当前流行的直接法都采用了基于两群模式的暂态能量函数,认为多机系统的暂态稳定性仅取决于该特定扰动下的两个互补机群间的相对运动,并据此对群内的能量进行了校正。显然,校正中的不一致性将会引入误差。另一方面,群际能量并不是封闭的,它和群内能量之间的互相转换是这类直接法的又一个重要误差源。当同一群内的各机动态响应相差甚远时,这种情况可能变得十分严峻。本文综合分析了暂态能量的校正问题,并介绍了在保持EEAC言简意赅特点的前提下尽量减少此类误差方面所取得的最新成果。 在所有针对群内动能或势能进行校正的直接法中,临界群和余下群的速度或功角对暂态能量的作用是相反的。正确识别临界群是直接法成功的基本前提,而有效地推荐候选的临界群,使需要试探的候选群数目尽量减少则关系到直接法的速度优势。这个长期困扰着直接法的问题最近也被出色地解决了。本文对有关的成果和下一步需要解决的问题进行了讨论。     

Ignitable Liquid Classification and Identification Using the Summed-Ion Mass Spectrum

Abstract

The mass spectra calculated by summing the intensities of each nominal mass over all chromatographic times, the summed ion spectra, were calculated for a set of 440 commercially available ignitable liquids that had been analyzed by gas chromatography–mass spectrometry. Each ignitable liquid is generally comprised of a mixture of chemicals, and the mixtures may be very complex in some cases, e.g., petroleum distillates, gasoline, etc. The summed ion spectra were evaluated to determine if they contained sufficient information content to allow their use for rapid and accurate identification of the ignitable liquid in a database or library. The summed ion nominal mass spectra were encoded in one bit per channel at 1% transition intensity and a set of 96,580 unique pairwise comparisons were made between spectra, resulting in an average of approximately 50 differing channels per comparison. A subset of 62 summed ion spectra were further compared by a similarity metric and found by cluster analysis to group closely along the ASTM ignitable liquid classification scheme. Receiver operator characteristic analysis of the use of the similarity index in combination with the summed ion spectra was shown to provide 99% probability of correct liquid identification and 95% probability of correct ASTM classification by primary and sub-class. Interlaboratory tests found 95% probability of correct liquid identification and 85% probability of correct ASTM classification at the primary class level. These results demonstrate the use of the summed ion spectrum as a first step in the rapid identification of an ignitable liquid by database or library searching.