基于进程代数规约生成软件体系结构模型的方法

需求规约到软件体系结构(SA)模型的转换是软件工程领域的一个研究热点,UML-RT广泛用于实时系统软件体系结构建模,然而基于自然语言规约建立的UML-RT模型往往是不精确的,存在二义性,为了解决这一问题,需要赋予UML-RT模型形式化语义.进程代数是一种用来解决并发系统通信问题的形式化方法,具有精确的语法和语义,并且便于机器自动检验与验证.TCSP是进程代数CSP的实时扩展,适合于规约实时系统带有时间约束的行为.提出一种基于进程代数规约生成SA模型的方法.首先建立了自然语言规约到SA模型的转换框架;然后使用时间通信顺序进程(TCSP)描述实时系统需求规约,通过建立TCSP到UML-RT的转换机制,从而实现进程代数规约到SA模型的转换;最后通过一个实例来验证该方法在实时软件建模过程中的有效性.实验分析表明通过该方法建立的UML-RT模型能够从整体上提高实时系统SA设计的可信性.     

UML-RT在实时系统中的应用研究

采用UML-RT为实时应用的结构和行为建模的基本概念及策略,给出了实时系统分析和设计的方法;并以一个实时系统的结构模型和行为模型的实现为例,说明了利用UML-RT进行实时系统建模的具体过程.     

UML-RT到一个图形设计环境体系结构的映射

为解决把UML-RT建模模型平滑过渡到实时系统的图形化的软构件设计开发环境的设计模型，本文提出了从UML-RT的结构模型映射到该环境下的体系结构模型的高层设计的映射方法。首先介绍UML-RT结构建模的概念及笔者研制的设计环境，其次给出从UML-RT映射到该设计环境体系结构模型的具体方法、约束和限制。     

基于B方法的体系结构描述语言的形式化研究

通过分析B方法和软件体系结构描述语言ABC/ADL各自的特点,提出了一种两者结合的形式化方法。该方法利用B方法扩充的事件机制,定义软件体系结构描述语言的构件和连接子观察模型、行为规约和约束规约,并给出了规约实例,从而使得基于B方法的ABC/ADL能够形式化描述软件体系结构的结构和行为。     

利用UML-RT序列图支持基于事务的SoC系统级功能验证

SoC基于事务的验证方法面临的一个重要问题是如何设计验证系统级复杂交互行为的事务测试序列。基于场景的序列图是设计人员捕获系统级功能规约的良好方法。本文提出了一种利用UML-RT序列图捕获SoC各个IP核之间的通信协作行为,为基于事务的验证建立高层规约,指导系统级测试序列生成的方法。我们自行开发了一个基于构件的事务验证环境SoC-CBTVE,并在该环境中利用本文的方法对一个典型的SoC设计进行了验证和分析。实验结果表明,利用UML-RT序列图能够捕获SoC系统级IP核之间的复杂通信行为,有效支持SoC系统级功能验证。     

实时UML及其在月球车实时软件开发中的应用

实时UML(UML-RT)是统一建模语言(Unified Modeling Language,UML)在实时系统的扩展和应用,其简洁清晰的面向对象可视化建模方法可以有效解决实时系统中的复杂建模问题;分析了应用实时UML概念和原理进行实时系统可视化建模的问题和方法,并以包含多个子系统的复杂实时系统-月球车系统为例,论述了应用实时UML进行实际软件设计的过程和问题;使用实时UML使得设计过程形象和易于组织,同时方便了项目成员间的交流,大大加快了软件开发的进程。     

软件体系结构的性能评价研究

介绍了软件体系结构的形式化描述方法-化学抽象机(ChemicalAbstractMachine,CHAM),总结了队列网络模型(QueueingNetworkModel,QNM)及其产生过程的特点。基于队列网络模型,由化学抽象机中形式化描述的软件体系结构规约,导出了一种性能评价模型。其目的是提供一个测量集,在高抽象层次上比较两个或更多候选软件体系结构的性能。最后,以多相编译器为例,具体阐述了这种性能评价。     

UML—RT到一个实时多任务执行模型的转换

为解决把UML-RT行为建模模型平滑过渡到实时多任务系统的图形化软构件设计开发环境的过程设计模型中，本文提出了把UML-RT状态图行为模型转换到该环境下的执行模型的方法。首先介绍UML-RT状态图建模的概念及笔者研制的设计环境，其次给出从UML-RT状态图转换到该设计环境可执行模型的具体方法，最后以一个实例说明了转换方法。     

面向体系结构的构件接口模型及其形式化规约

借鉴软件体系结构的思想,提出了面向体系结构的构件接口模型,它既能表达体系结构设计的高层抽象构件,又能表达底层代码级别的实现构件。同时基于该模型,运用顺序通信进程,提出了两级构件接口行为协议规约方法,能够有效规约大粒度复杂软件构件的行为交互协议。     

基于UML-RT的复杂嵌入式系统建模方法及其应用

分析了UML在实时系统设计中的优点和需要解决的主要问题,论述了基于UML RT的实时嵌入式系统设计方法,并且对其进行扩展以支持数据流计算模型的建模,最后以汽车巡航系统为例加以说明。     

Towards UML-based formal specifications of component-based real-time software

UML-RT is achieving increasing popularity as a modeling language for real-time applications. Unfortunately UML-RT is not formally well defined and it is not well suited for supporting the specification stage: e.g., it does not provide native constructs to represent time and non-determinism. UML+ is an extension of UML that is formally well defined and suitable for expressing the specifications of real-time systems (e.g., the properties of a UML+ model can be formally verified). However, UML+ does not support design and development. This article addresses the translation of UML+ into UML-RT, thus posing the basis for a development framework where UML+ and UML-RT are used together, in order to remove each other’s limitations. Specifications are written using UML+, they are automatically verified by means of formal methods, and are then converted – through a semi-automatic process – in an equivalent UML-RT model that becomes the starting point for the implementation.     

Rapid prototyping of protocols from LOTOS specifications

A new tool for generating implementation prototypes of communication protocols and concurrent systems specified using the ISO LOTOS language is presented in this paper. A brief introduction to LOTOS and a discussion of the main problems related to the efficient execution of specifications written in LOTOS are presented first. The design and implementation of the tool are then considered: LOTOS specifications are analysed and translated into C functions which are executed by co-operating processes in the Unix environment. The set of LOTOS process definitions is first translated into a suitable number of extended finite-state machines (EFSMs). The method proposed allows the problem of deriving unbounded EFSMs to be circumvented and a sort of control on the process number/size trade-off to be obtained at the same time. The problem of implementing the LOTOS multi-way rendezvous mechanism for process synchronization is solved by using an algorithm based on message-passing techniques. An example of prototype derivation is also described, showing the form of C code generated by translating a simple specification. Finally, some performance figures are presented.     

实时软件系统开发技术

分析了开发实时系统和实时软件系统的特殊性，讨论了传统实时软件系统开发技术(包括RTSA技术、DARTS技术、JSD技术、NRL方法、OOA＆OOD技术等)，并比较了它们各自的优缺点．详细讨论了面向对象技术在实时软件系统开发中的应用，对统一建模语言(UML)在实时软件系统中的应用也进行了深入分析和讨论．在分析了实时UML(UML-RT)的不足之后，提出了融合UML和CPN的实时软件开发技术，并用一个实例说明了如何利用该技术进行实时软件开发．     

网络协议设计中形式结构模型的创建方法研究

形式描述技术在协议设计中的应用是至关重要的和必不可少的,为形式规范确定一个合适的结构又是应用此技术的关键步骤,基于此文中重点研究了基于LOTOS技术的形式结构模型的创建方法。简要介绍了开发网络协议的形式描述技术、网络协议的结构概念、等级抽象和LOTOS描述规范风格。基于LOTOS技术,提出了网络协议开发过程中形式结构模型的创建原则和方法,此方法结合LOTOS语言特征,应用其描述规范风格,融协议结构、逐步改进和等级抽象为一体,简化了所开发协议的验证、测试和实现的复杂性。     

An executable formal semantics for UML-RT

We propose a formal semantics for UML-RT, a UML profile for real-time and embedded systems. The formal semantics is given by mapping UML-RT models into a language called kiltera, a real-time extension of the \(\pi \)-calculus. Previous attempts to formalize the semantics of UML-RT have fallen short by considering only a very small subset of the language and providing fundamentally incomplete semantics based on incorrect assumptions, such as a one-to-one correspondence between “capsules” and threads. Our semantics is novel in several ways: (1) it deals with both state machine diagrams and capsule diagrams; (2) it deals with aspects of UML-RT that have not been formalized before, such as thread allocation, service provision points, and service access points; (3) it supports an action language; and (4) the translation has been implemented in the form of a transformation from UML-RT models created with IBM’s RSA-RTE tool, into kiltera code. To our knowledge, this is the most comprehensive formal semantics for UML-RT to date.     

Use of a formal description technique in the specification of authentication protocols

Formal specification techniques have been employed over the past decade or so by various workers in data communication and computer network systems in order to provide both definitional specifications of protocols and models of protocols for analytic purposes. This paper considers the use of the specification language LOTOS (Language of Temporal Ordering Specification) for specifying some authentication protocols developed in the security field. The language LOTOS recently became an International ISO Standard and the protocols specified form part of the ISO and CCITT Standards. In fact, the CCITT protocol which is considered in this paper, has been used in the LOCATOR (X.400 Secure Mail) project within HPLabs. We first give a brief introduction to LOTOS and then specify two security protocols from ISO/DP 9798 and CCITT X.509 Standards. We feel that a formal specification of protocols is a useful and a necessary step towards understandability, analysis and implementation of the protocols. Further, we feel that LOTOS possesses the necessary features required for specifying such protocols.