基于软件体系结构与软件构件技术的开发方法的研究与实现

基于构件的软件开发方法,关注于运行级构件及其相互作用,借助于构件模型技术,提供了构造应用系统的有效途径,但缺乏能够指导整个开发过程的系统方法。软件体系结构以构件作为应用系统的基本构造单元,从整体上反映软件的组织结构、设计思想和实现技术,为基于构件的开发提供了一个自顶向下的途径。对软件体系结构和软件构件技术进行了分析研究,对分布式基于Web的应用,给出了以体系结构为指导、基于构件的开发方法。运用以体系结构为指导、基于构件的开发方法与J2EE平台规范相结合,为建设机械制造公司设计开发了ERP系统。该系统具有分布式基于Web应用的特点,具有良好的开放性、集成性和适应性,各项性能均达到了设计要求。     

基于扩展的粒度计算的软件体系结构模型:EGSA

针对目前软件体系结构理论基础及ADL的不足,尤其是不支持体系结构风格自动发现的缺陷,通过对传统的粒度计算进行扩展,使其能处理粒度间结构关系,建立了软件体系结构模型EGSA(Extended Granular Computing-Based Software Architecture Model).EGSA可表达结构多维语义,支持体系结构分层构造、属性分析,并考虑了结构信息对复合构件属性的影响;通过解码和模糊集运算,EGSA具备自动发现新的体系结构风格的能力.EGSA是较完整的理论体系,为进一步的研究提供了理论工具.     

雷达组网软件体系结构研究

借鉴美军C4ISR体系结构相关研究成果,简要介绍软件体系结构的开发方法和内容,针对雷达组网在预警探测领域的特点,给出雷达组网中的软件体系结构设计的基本思想。从作战视图、系统视图和技术视图三个方面描述雷达组网软件体系结构,包括软件体系结构框架、设计模式、软件构件与重用和模型评估等方面的内容,满足系统体系结构设计的需要。     

一门新的面向构件语言

作为软件体系结构的重要贡献之一，连接子显式地描述了构件之间的交互．本文认为连接子的重要性值得我们在程序设计语言中加以支持．提出了一门新的面向构件语言SAJ，把构件，端口，连接子等软件体系结构概念引入到SAJ中．连接子与构件在SAJ中都是一阶实体，使得软件体系结构在底层实现中更加显式化，而且能更好地支持构件和连接子的复用．给出了SAJ语言的语法、语义和类型系统，并说明其具有类型安全性．     

一种软件体系结构级测试序列生成技术

软件体系结构(software architecture,SA)通过对系统构件及其交互的抽象,提供了一个描述大型、复杂系统的高层次模型,软件体系结构的动态描述常被用来指导分析和测试.本文通过CHAM(chemical abstract ma-chine,CHAM)描述的SA规格说明生成LTS,并根据测试需求进行测试功能的选取,提出了基于功能的最小LTS图(M-LTS)生成方法,根据McCabe覆盖方法生成M-LTS图的测试路径.最后以B/S结构为例,验证了该方法在生成SA级的测试路径上是可行的.     

一种新型的软件体系结构描述方法研究

UML2．0与XYZ／ADL在软件体系结构描述方面具有很强的互补性，如果将两者结合起来描述软件体系结构．不仅便于开发人员之间的理解和交流，也可以对体系结构进行下一步的分析和验证。文章分析了UML2．0跟UML1.X相比在软件体系结构描述方面的改进之处．根据UML2．0与XYZ／ADL在软件体系结构描述中的对应关系，提出一种通过定义UML2．0的XYZ／E语义．将UML2.0与XYZ／ADL结合起来描述软件体系结构的一种新的途径。     

构件软件体系结构

本文系统地介绍了构件软件体系结构产业，发展和概念模型，结合国际上的先进成果和我们自己的开发经验，经基于构件软件体系结构的应用系统的开发工作阐述了自己的认识，本文结尾提出了对于构件体系结构未来发展的展望。     

基于框架/构件的虚拟仿真概念

介绍了一种基于构件的软件体系结构,在该体系结构下设计的虚拟仿真系统可以实现最大程度上的通用性。     

软件体系结构层的耦合性度量研究

提出一种软件体系结构层耦合性度量套件,分别定义了CBC度量构件问耦合、CBCC度量构件问消息传递集耦合及CBCCT度量系统全局耦合,并根据提出的耦合性度量算法,为体系结构设计提供设计依据,最后通过实例分析了该度量套件的可行性.     

基于层次消息总线的软件体系结构描述语言

以青鸟软件生产线的实践为背景,提出了基于层次消息总线的软件体系结构风格JB/HMB,并设计了相应的体系结构描述语言JB/SADL,该语言支持从接口、静态结构和动态行为三个方面刻画构件.采用JB/SADL,可以方便地进行软件体系结构的构造、细化和验证,并具有快速生成原型的能力,还支持代码框架的自动生成和系统体系结构的动态演化.     

SysML状态图合理性验证研究与实现

给SysML赋予形式化语义,可在目标系统生成前,对系统的模型进行合理性验证。模型在实现前就被验证,可减少目标系统的测试周期。文中用SysML状态图表示系统的行为模型,通过体系结构和业务需求两方面对行为模型进行验证。按照语义规范和性能需求的标准验证状态图的体系结构。另一方面,在体系结构正确性的基础上,执行带有动作规约语言的状态图,可得到状态图对象的行为过程。并通过判断该行为过程与人们所期望的是否一致,再对业务需求进行验证。最终通过实验验证了该方法的有效性和可行性。     

一种面向嵌入式软件体系结构的形式化建模方法

为了解决MARTE（Modeling and Analysis of Real Time and Embedded systems）在建立嵌入式软件模型时不够精确的问题,结合Object-Z和PTA（Probabilistic Timed Automation）的优点,本文提出了一种集成的形式化建模方法--PTA-OZ.该方法不仅能够对嵌入式软件模型的静态语义和动态语义进行精确描述,而且通过模型转换规则,能够将MARTE模型转换为PTA-OZ模型.并对模型转换的语义一致性进行了验证,证明本文方法在转换过程能够保持结构语义和行为语义的一致性.最后通过实例模型描述从嵌入式软件建模到属性检验的过程.     

Specification and analysis of power-managed systems

Dynamic power management encompasses several techniques for reducing energy dissipation in electronic systems by selective slowdown or shutdown of components. We present a theoretical framework for explaining and classifying different approaches to power management. Within this framework, we model power-manageable components, workloads, and controllers as discrete-event systems (DESs). The structure of these DESs is specified in terms of physical states (representing operation modes) and events (triggering state transitions), while system behavior is specified in terms of next-event and next-state functions. In particular, nondeterministic next-event and next-state functions are modeled by conditional probability distributions, according to generalized semi-Markov processes (GSMPs). The modeling framework provides a general denotational model for system specification and a rigorous execution semantics that enables event-driven simulation. We introduce a modeling framework, built on top of MathWork's Simulink, supporting the specification and execution of our model. In particular, we present templates for the Simulink simulator to execute GSMP models, and we describe how to use such templates for specifying, analyzing, and optimizing dynamic power-managed systems. Finally, we demonstrate the expressive power and versatility of the proposed approach by using the modeling framework and the simulator for the analysis of representative real-life case studies, including the Intel Xscale processor architecture, a multitasking real-time system, and a sensor network.     

GTHBAC: A Generalized Temporal History Based Access Control Model

Time plays a crucial role in access control for new computing environments, which is not supported in traditional access control models. In this paper, we propose a Generalized Temporal History Based Access Control (GTHBAC) model, aimed at integrating history-based constraints along with a generic access control model. GTHBAC enhances the specification of user-defined authorization rules by constraining time interval and temporal expression over users’ history of accesses. Due to different application needs, GTHBAC uses two different time schemes, i.e., real time and logical time, in its authorization rules. A formal semantics for temporal authorizations is provided, and conflicting situations are also investigated and resolved in the model. To represent the applicability of the proposed model, an architecture for an access control system based on the model is proposed, and a case of employing the model in specifying and enforcing access control policies in a banking system is studied. The operators of GTHBAC are also compared with Linear Time Temporal Logic (LTL) operators to show the expressive power of the model.     

Semantics-based dynamic service composition

Complex services may be dynamically composed through combining distributed components on demand (i.e., when requested by a user) in order to provide new services without preinstallation. Several systems have been proposed to dynamically compose services. However, they require users to request services in a manner that is not intuitive to the users. In order to allow a user to request a service in an intuitive form (e.g., using a natural language), this paper proposes a semantics-based service composition architecture. The proposed architecture obtains the semantics of the service requested in an intuitive form, and dynamically composes the requested service based on the semantics of the service. To compose a service based on its semantics, the proposed architecture supports semantic representation of components [through a component model named Component Service Model with Semantics (CoSMoS)], discovers components required to compose a service [through a middleware named Component Runtime Environment (CoRE)], and composes the requested service based on its semantics and the semantics of the discovered components [through a service composition mechanism named Semantic Graph-Based Service Composition (SeGSeC)]. This paper presents the design, implementation and empirical evaluation of the proposed architecture.     

Risk assessment of software-system specifications

This paper presents a methodology and an example of risk assessment of functional-requirement specifications for complex real-time software systems. A heuristic risk-assessment technique based on CPN (colored Petri-net) models is presented. This technique is used to classify software functional-requirement specification components according to their relative importance in terms of such factors as severity and complexity. A dynamic complexity measure, based on concurrence in the functional requirements, is introduced. This technique is applied on the Earth Operation Commanding Center (EOC COMMANDING), a large component of the NASA Earth Observing System (EOS) project. Two specification models of the system are considered. Results of applying this technique to both CPN models are presented. The risk assessment methodology in this paper suggests the following conclusions: (i) risk assessment at the functional-requirement specification phase can be used to classify functional requirements in terms of their complexity and severity; (ii) dynamic complexity metrics and the concurrence metric can be important in assessing the risk factors based on the complexity of functional specifications; (iii) the concurrence complexity metric is an important aspect of dynamic complexity; and (iv) CPN models can be used to build an executable specification of the system, which helps the analyst not only to acquire deep understanding of the system but also to study the dynamic behavior of the system by simulating the model     

Procedural knowledge

Much of commonsense knowledge about the real world is in the form of procedures or sequences of actions for achieving particular goals. In this paper, a formalism is presented for representing such knowledge using the notion of process. A declarative semantics for the representation is given, which allows a user to state facts about the effects of doing things in the problem domain of interest. An operational semantics is also provided, which shows how this knowledge can be used to achieve particular goals or to form intentions regarding their achievement. Given both semantics, our formalism additionally serves as an executable specification language suitable for constructing complex systems. A system based on this formalism is described, and examples involving control of an autonomous robot and fault diagnosis for NASA's space shuttle are provided.     

基于领域特征本体的构件语义描述和组装

构件的功能语义是复用者了解并判断构件可复用性的重要依据，因此必须在构件开发者和复用者共同的知识基础上进行构件描述．目前已有一些方法引入本体作为构件语义描述的基础，但仍然存在语义描述不够精确以及无法支持语义的组装推导等不足．引入了领域分析中提出的基于本体的领域特征模型作为构件语义描述基础，在此基础上给出了构件端口语义、静态语义、语义协议的定义以及语义组装算法．基于构件静态语义和组装算法可以在构件组装时进行语义合成，从而辅助开发者进行基于语义的构件适配和组装分析．