面向体系结构的可视化服务集成开发环境Artemis-VIDE

为支持直观易扩展的软件服务集成和所集成之应用系统的动态演化，本文提出了一个面向体系结构的可视化服务集成开发环境。该环境支持以图形化的方式定义系统的软件体系结构及相关协同逻辑，并据此生成内置于应用系统之中的运行时刻体系结构对象，作为应用系统运行和演化的基础。该环境还集成了服务搜索、基于图文法的体系结构检查等功能，为系统的开发、运行、监控和动态演化提供了一个一致、易用、可扩展的支撑平台。     

一种分布式系统动态演化机理研究

软件体系结构提供了系统动态演化的基础．基于特定体系结构风格，对支持分布式软件系统动态演化机 理进行研究和实践．为此，首先描述层次消息总线体系结构风格，并就相关的动态演化类型和演化流程进行讨论，最 后以区域集成服务器作为消息总线的实现机制，支持符合层次消息总线体系结构风格的分布式系统动态演化．     

一种面向服务的动态协同架构及其支撑平台

为了让面向服务的架构下的应用系统能够灵活地动态演化以适应底层因特网计算环境和用户需求的变化，该文提出了一种面向服务的动态协同架构．该架构引入内置的运行时体系结构对象来解耦系统中的各个服务构件，并通过该对象以体系结构的视角来重解释服务部件之间的引用和交互．这样就把体系结构这一抽象概念具体化为可直接操控的对象，从而可以利用面向对象程序设计语言的继承和多态等整套机制，导出一种面向体系结构的系统动态演化技术．为支持这一架构，设计并实现了一个支撑平台Artemis-ARC，为具有动态调整能力的面向服务应用系统的开发、运行和监控提供了一套可视化的集成环境．在此平台上还开发了一个简单的示例应用以展示动态调整的效果．     

一种面向动态软件体系结构的在线演化方法

为适应计算环境和用户需求在系统运行期间的变化,满足软件系统进行动态演化的需求,提出面向动态软件体系结构的在线演化方法,设计并实现了一种运行时刻的软件体系结构元模型,将原先运行时刻不可见的体系结构设计信息具体化为显式的体系结构实体,并与系统实现及系统规约之间保持因果关联.元模型的演化可通过反射实现对运行系统的修改和对规约的更新,所有演化行为都在良定义的体系结构元模型的指导下规范地进行,保证了演化前后系统的一致性、完整性和演化的可追溯性.基于该方法开发了可视化支撑平台Artemis-ARC系统,支持构件和服务的设计、开发、集成及动态演化,并通过简单的应用实例展示了在线演化的效果.     

一种基于工具总线的CASE环境体系结构风格研究与设计

从软件体系结构的角度，在工具总线(ToolBus)的基础上，提出了一种抽象的CASE环境体系结构风格TBus，并对体系结构模型、系统行为以及相应的工具结构模型、工具适配器结构模型等进行了深入的研究与分析，最后对TBus体系结构风格的优缺点进行了评价．建立TBus体系结构风格，对于分布式CASE环境和软件平台的开发具有重要的促进作用．     

基于图文法的动态软件体系结构支撑环境

使用类型化的属性图及其图文法来直观而形式地刻画软件体系结构和体系结构风格,用图转换来刻画动态体系结构的重配置行为.基于这种刻画,构建了一个动态软件体系结构支撑环境.该环境一方面,通过一个基于图文法的编辑器来支持体系结构图模型的可视化构造和操纵;另一方面,基于内置运行时体系结构技术实现了体系结构图模型在具体系统中的物理实施,并使得图模型上的图转换操作可以自动映射到实际系统的动态重配置上.再加上一系列的辅助设施,形成了一个较为完整的基于图文法的动态软件体系结构支撑环境.     

基于分布式构件的媒体流模型研究

本文提出一个分布式媒体流应用模型DCMM，DCMM以构件和软件代理技术为基础，形式化地定义了媒体流应用系统的软件体系结构，即组成系统的构件和构件之间的交互关系，在该模型中，媒体流应用构件描述与底层协议相分离，实现了媒体流应用的体系结构与网络平台的无关性，该模型允许构件之间以多种方式交互，允许动态地选择网络传输协议，因此具有较好的灵活性。     

基于XYZ/ADL的网络中心化仿真运行支撑平台体系结构形式化描述

网络中心化仿真运行支撑平台体系结构是为了满足动态构建仿真任务共同体而提出的相应支撑环境。采用基于XYZ/ADL的双重软件体系结构描述框架,分别从图形语言和形式语言对仿真运行支撑平台体系结构进行了描述并对仿真任务共同体构建中仿真核心服务层实施了分解与逐步求精。该体系结构描述方法不但从可视化角度表示了仿真运行支撑平台体系结构框图及行为抽象,还从形式化角度验证了体系结构设计的正确性和完整性。该研究是形式化描述方法在军事领域的全新尝试,为仿真运行支撑平台服务的合成与重用机制提供了形式化的理论指导。     

以体系结构为指导的基于构件的软件开发方法研究

分析了软件体系结构和软件构件技术，研究了基于分布式的Web应用的主要结构形式。以体系结构为指导的基于构件的软件开发方法将软件体系结构的思想贯穿到基于构件开发的各个阶段，正确指导开发过程的进行。     

Runtime software architecture based on reflective middleware

Copyright by Science in China Press 2004 Since its first literate identification and discussion[1], software architecture (SA) has become an important subfield of software engineering, receiving increasing attention from both academic and industrial communities. SA describes the gross structure of a software system with a collection of components, connectors and constraints[2]. In gen-eral, SA acts as a bridge between requirements and implementation and provides a blue-print for system cons…     

Using architecture models for runtime adaptability

Every software system has architecture. The architecture strongly influences the software system's properties, including maintainability and runtime properties such as performance and reliability. By describing the architecture in models, we can make the architecture explicit. Developers typically use software architecture models at design time to capture the significant decisions about a software system's organization and to describe and establish a common understanding about the system's abstract properties. In the MADAM (mobility- and adaptation-enabling middleware) project, we aim to facilitate adaptive application development for mobile computing. We follow an architecture-centric approach where we represent architecture models at runtime to allow generic middleware components to reason about and control adaptation.     

The role of models@run.time in supporting on-the-fly interoperability

Models at runtime can be defined as abstract representations of a system, including its structure and behaviour, which exist in tandem with the given system during the actual execution time of that system. Furthermore, these models should be causally connected to the system being modelled, offering a reflective capability. Significant advances have been made in recent years in applying this concept, most notably in adaptive systems. In this paper we argue that a similar approach can also be used to support the dynamic generation of software artefacts at execution time. An important area where this is relevant is the generation of software mediators to tackle the crucial problem of interoperability in distributed systems. We refer to this approach as emergent middleware, representing a fundamentally new approach to resolving interoperability problems in the complex distributed systems of today. In this context, the runtime models are used to capture meta-information about the underlying networked systems that need to interoperate, including their interfaces and additional knowledge about their associated behaviour. This is supplemented by ontological information to enable semantic reasoning. This paper focuses on this novel use of models at runtime, examining in detail the nature of such runtime models coupled with consideration of the supportive algorithms and tools that extract this knowledge and use it to synthesise the appropriate emergent middleware.     

Managing complexity: middleware explained

Traditionally, most definitions seeking to characterize middleware suggest that it is the software that facilitates remote database access and systems transactions. More recently, the term has come to be associated-somewhat limitingly-with distributed platforms such as the Open Software Foundation's Distributed Computing Environment (DCE) and the Object Management Group's Common Object Request Broker Architecture (CORBA). And some have loosely applied it to systems as diverse as workflow support environments and even to the Web itself. We believe the essential role of middleware is to manage the complexity and heterogeneity of distributed infrastructures and thereby provide a simpler programming environment for distributed-application developers. It is therefore most useful to define middleware as any software layer that is placed above the distributed system's infrastructure-the network OS and APIs-and below the application layer     

DSCM:一个支持动态演化的服务组件架构模型

针对服务组件架构(Service Component Architecture,SCA)的动态管理和演化的不足,文章研究SCA的动态重构技术.在符合SCA模型规范基础上结合开放服务网关规范(Open Service Gateway Initiative,OSGi)技术,提出一个开放环境下的动态服务组建模型DSCM(Dynamic Service Component Model),它以Object Teams技术作为基础设施,从而提高应用系统的可理解性、重用性、扩展性、适配性和进化能力.DSCM支持分布式和异构平台的整合,支持简单老式java对象(Plain Old Java Object,POJO)增强和管理的机制,使得框架具有通用性和无入侵性.     

Online approach to feature interaction problems in middleware based system

As a popular infrastructure for distributed systems running on the Internet, middleware has to support much more diverse and complex interactions for coping with the drastically increasing demand on information technology and the extremely open and dynamic nature of the Internet. These supporting mechanisms facilitate the development, deployment, and integration of distributed systems, as well as increase the occasions for distributed systems to interact in an undesired way. The undesired interactions may cause serious problems, such as quality violation, function loss, and even system crash. In this paper, the problem is studied from the perspective of the feature interaction problem （FIP） in telecom, and an online approach to the detection and solution on runtime systems is proposed. Based on a classification of middleware enabled interactions, the existence of FIP in middleware based systems is illustrated by four real cases and a conceptual comparison between middleware based systems and telecom systems. After that, runtime software architecture is employed to facilitate the online detection and solution of FIP. The approach is demonstrated on J2EE （Java 2 Platform Enterprise Edition） and applied to detect and resolve all of the four real cases.     

基于AOP和反射计算的动态自适应中间件

Internet为分布式应用提供了一种开放,动态的运行环境,为了使作为分布式应用主要基础设施的中间件能够支持运行时监测并调整系统的内部状态、结构和行为,能够根据运行过程中的环境变化对应用程序的属性和行为做相应的调整,结合使用AOP和反射计算技术的优点,并将AspectLua集成到中间件,中间件的应用配置信息用Lua编写,从而使得构造的中间件具有较好的自适应性。     

基于软件体系结构的反射式中间件研究

Internet为分布应用提供了一种开放、动态的运行环境,这要求分布应用的主要基础设施中间件能够支持运行时查看并调整平台内部状态和行为,由此产生了反射式中间件.目前的反射式中间件研究与实践存在3个不足:注重系统局部或单个实体的反射而缺乏全局视图;注重中间件平台内部功能的反射,而对上层应用的反射不够;集中于CORBA平台,而对J2EE平台的反射性研究较少.介绍了一个反射式的J2EE应用服务器PKUAS.基于构件化的平台内部体系结构,PKUAS引入软件体系结构作为全局视图以实现反射体系对系统整体的表示和控制,作为J2EE应用服务器,PKUAS可反射底层平台以及上层EJB构件.同时,以PKUAS实时监控工具为例,探讨了如何利用基于软件体系结构的反射体系管理整个系统,并给出了PKUAS与其他几种反射式中间件的比较.该工作有效地解决了现阶段反射式中间件研究的不足,提高了反射式中间件的实用性.