Semantics and verification of monitors and systems of monitors and processes

In this paper we present a sound and complete semantics for the monitor concept of C.A.R. Hoare. First a method for specification of monitors, introduced by O.-J. Dahl, is reviewed. This method is based on the relation between the historic sequence of monitor procedure calls and the historic sequence of monitor procedure exits. Based on such specifications and our new monitor semantics we present a method by which it is possible to prove that a concrete monitor is an implementation of an abstract one. In the last part of the paper an axiomatic semantics for systems of concurrent processes and monitors is introduced. The method supports verification by separation of concerns: Properties of the communication to and from each process are proven in isolation by a usual Hoare style axiomatic semantics, while abstract monitors are also specified in isolation by the method reviewed in the first part of the paper. These properties of the components of the system are then used in a new proof rule to conclude properties of the complete system. Stein Gjessing received a Ph.D. (actually a Dr. philos.) from the University of Oslo (Norway) in 1985. Presently he is an Associate Professor at the Institute of informatics, University of Oslo, Norway. Dr. Gjessings research interests are in the area of concurrent and distributed programming, operating systems, formal specification and verification and programming languages.     

Models and Complexity of Problems of Design and Reconstruction of Telecommunication and Transport Systems

This article considers network synthesis problems arising in the design and exploitation of telecommunication and transportation systems. A formalization of network synthesis problems on graphs is proposed in which constraints on cut capacities are given and possibilities of failing some network components are taken into account. Approaches to the solution and analysis of the complexity of the considered problems are described.     

Teamcenter与NX集成客户化定制技术研究与实现

PDM产品实施过程中一项重要工作是系统集成与客户化定制。对Teamcenter Engineering(简称Teamcenter)与NX系统集成客户化定制中业务建模、属性映射等相关技术进行了研究,提出了Teamcenter与NX集成客户化定制的技术思路,并以客户化定制NX工程图纸标题栏为例,介绍了Teamcenter与NX集成定制实现的关键步骤及方法。     

Binary perfect and extended perfect codes of lengths 15 and 16 and of ranks 13 and 14

Inaccuracies in computations in the paper of the authors on classification of perfect binary codes of lengths 15 and 16 and of rank 13 are fixed. An explicit construction of all extended perfect codes of length 16 and rank 13 with a given kernel size is presented. Perfect binary codes of length 15 and rank 14 obtained by the general doubling construction are classified.     

椭圆拉伸变形长短轴的计算及应用

在CAD应用软件程序编制中,椭圆的长短轴是很重要的参数。应用相关数学知识推导出6个计算公式,可利用这些公式确定椭圆沿坐标轴拉伸变形后的长短轴大小与位置并在CAD软件中实现与之相关的功能。     

智能业务和软交换互通的设计与实现

电信业的快速发展及下一代网络的全面建设促进智能业务与软交换实现互通。文中首先介绍了互通的种类和方案，并重点讲述了智能网和软交换互通过程中模型的重要部分——软交换侧的SSP。在此基础上，提出了智能网和软交换互通的实现方案，并且以智能用的典型业务FPH为例简明分析了方案，对利用业务服务器实现软交换中的智能业务进行了插述和分析。     

智能业务和软交换互通的设计与实现

电信业的快速发展及下一代网络的全面建设促进智能业务与软交换实现互通.文中首先介绍了互通的种类和方案,并重点讲述了智能网和软交换互通过程中模型的重要部分--软交换侧的SSP.在此基础上,提出了智能网和软交换互通的实现方案,并且以智能网的典型业务FPH为例简明分析了方案,对利用业务服务器实现软交换中的智能业务进行了描述和分析.     

IPSEC与防火墙协同工作设计与实现

IPSEC提供网络层的安全服务，通过对IP报文的加密和验证，保证数据在传输过程中的安全．由于IPSEC封装了报文中一些重要信息，使得IPSEC与防火墙不能同时有效地工作．本文提出一种分层IPSEC(Layered IP Security，L_IPSEC)思想，即将协议头和数据部分分别进行安全处理．并将这种分层思想与分布式处理技术结合，设计与实现一种IPSEC与防火墙协同工作方案．     

Kohonen与Madaline用于解析重叠光谱测定钨和钼

首先应用Kohonen网络对钨、钼的混合吸收光谱进行波长选择，在全光谱中优选最能代表光谱特征的波长，被选波长处吸光度作为Madaline网络的输入，设定输出目标函数为G（λ）＝∑Aiexp[-4(ln20）(λ-t）^2/2]，进行解析重叠光谱，同时测定了钨和钼，该法利用特征光谱代表全谱进行光谱解析，减少了解析光谱中大量的数据。     

Assessment of the temperature and pressure dependence of molar volume and phase diagrams of Cu and Zn

This study reports the thermodynamic assessment of the temperature and pressure dependence of molar volume of Cu and Zn, as well as their P–T phase diagrams based on the CALPHAD approach. The molar volume of fcc-Cu, hcp-Zn, and liquid phases as a function of both temperature and pressure was directly assessed from the data reported in the literature by implementing the CALPHAD-compatible equation of state (EOS). This EOS incorporates the quasi-harmonic model to eliminate the spurious predictions of negative heat capacity and thermal expansion at high pressure. Furthermore, the P–T phase diagram of each element was determined on the basis of the experimental results and calculated parameters. The experimentally estimated thermodynamic values are in good agreement with the calculated results.     

XML和数据库之比较与转换

本文比较了XML与数据库的优缺点,并探讨了XML与数据库相互转换的问题。     

Detection of rotational and involutional symmetries and congruity of polyhedra

We propose a simple and efficient general algorithm for determining both rotational and involutional symmetries of polyhedra. It requiresO(m ²) time and usesO(m) space, wherem is the number of edges of the polyhedron. As this is the lower bound of the symmetry detection problem for the considered output form, our algorithm is optimal. We show that a slight modification of our symmetry detection algorithm can be used to solve the related conguity problem of polyhedra.     

PROFIBUS—DP主站和从站通讯的设计与实现

本文介绍了PROFIBUS现场总线技术的特点并结合SIEMENS公司的S7-300 PLC、通讯模块CP342-5及ET200 M 等相关产品组建PROFIBUS-DP网络.讨论了该网络的组态、STEP 7程序的编制以及现场设备GSD文件的建立方法,并详细讨论了PROFIBUS-DP主从站数据交换的实现方法.     

嵌入式TPM及信任链的研究与实现

为将可信计算技术更有效应用于嵌入式系统,结合链式与星型信任结构,提出了一种带数据恢复功能的混合式信任结构,可降低链式结构的信任损失,减轻星型结构中可信平台模块(TPM)的计算负担.在此基础上构建并实现了一种嵌入式可信平台,以内置可信度量核心根(CRTM)的嵌入式TPM作为信任根,并在其内部设计了双端口内存作为与嵌入式处理器间的通信接口.该平台在启动过程中通过CRTM验证启动程序及操作系统的完整性,利用操作系统动态拦截和验证应用程序的完整性,并在发现完整性度量值被修改时启动数据恢复功能,从而有效保证了嵌入式系统软件组件的完整性和可信启动.     

信息论与编码课程思政教学设计与实践

根据信息论研究及课程教学特点,在课程中加入课程思政教学,在课程目标、内容、考试考核等方面全方位融入,以讲好中国故事为主线,使信息专业基础教学与课程思政教学无缝衔接,对全国高校同类课程的课程思政工作有实际指导意义。     

网络侦听以及反侦听的原理和实现

首先简要介绍了网络侦听的原理及其潜在的安全隐患,讲述了侦听技术在Unix和Windows环境下的几种实现技术;说明了如何检测侦听器的存在;最后提出了一种切实可行的、用来消除网络侦听的方案。     

存储系统NAS和SAN的差异和统一

分析了目前已经实现的主流网络存储技术SAN和NAS之间的差异,比较了它们之间在各方面的优劣,描述了多种实现NAS和SAN融合的手段,指出网络化存储必然相统一和融合发展,得出了IP之上存储是未来发展方向的结论。     

全国多级、多分辨率图形图像控制点数据库建立及应用展望

控制点图形图像数据库的建立能够克服常规控制点获取技术中周期长、应用效率低、可重复利用率低的缺点, 是实现高效、高精度几何纠正的基础。详细介绍了全国多级、多分辨率图形图像控制点数据库的数据源选择标准、控制点采集技术指标、数据库建立与管理模式、数据库共享机制等。最后对全国多级、多分辨率图形图像控制点数据库的应用做了简单介绍和展望。     

数据驱动和关键字驱动的研究与应用

测试自动化是大型软件测试的一个重要测试环节,可以节省测试人力,对待测软件做最基本的评估,作用不可替代。但是自动化测试如果组织设计不到位,测试效果会比较差,已经做好的自动化成果也不能得到很好的应用。本文介绍的数据驱动和关键字驱动就是让测试数据从自动化脚本中分离出来单独维护,很好的解决了测试脚本的重用和维护问题。