基于CAFISE Framework的高适应性面向服务软件开发

在企业及电子政务应用中,由资源分布异构及需求动态变化而产生的问题越来越严重,如何让应用快速适应这些变化一直是人们关注的一个研究难题.首先给出了一个面向服务的支持业务端编程的适应性软件结构框架CAFISE(convergent approach for information system evolution)Framework,然后给出了基于该框架的面向服务的适应性软件开发方法.CAFISE Framework对异构资源的服务化、业务化及开放动态的面向服务软件体系结构提供了较好的支持.基于该结构框架的开发方法,从对影响软件的环境要素分析入手,通过质量属性驱动的体系结构分析,重点针对应用要适应的变化进行结构设计,最终通过以体系结构为基础的业务端编程,实现面向服务应用的即时开发与演化.在实际项目中的使用及实验证明:用该框架和方法开发的面向服务应用,能够较好地适应异构资源的动态变化及用户业务变更,能以较低的代价实现企业及电子政务面向服务应用的持续演化.     

软件动态演化技术

为适应开放环境和用户需求的变化,软件应该具备在运行时刻自演化的能力,从而满足各种需求变化,因此深入研究动态演化技术显得尤为重要。介绍了软件动态演化的开放性、层次性和整个演化活动的具体过程,讨论了动态演化的语言、模型和乎台三者之间的关系以及当前的研究成果,并对已有成果中的实现方法、实用性和特色进行了比较,指出其不足之处。最后提出动态演化技术应重点研究的关键问题,并对其发展前景进行展望。     

Requirements model driven adaption and evolution of Internetware

Today’s software systems need to support complex business operations and processes.The development of the web-based software systems has been pushing up the limits of traditional software engineering methodologies and technologies as they are required to be used and updated almost real-time,so that users can interact and share the same applications over the internet as needed.These applications have to adapt quickly to the diversified and dynamic changing requirements in the physical,technological,economical and social environments.As a consequence,we are expecting a major paradigm shift in software engineering to reflect such changes in computing environment in order to better address the fundamental needs of organisations in this new era.Existing software technologies,such as model driven development,business process engineering,online(re-)configuration,composition and adaptation of managerial functionalities are being repurposed to reduce the time taken for software development by reusing software codes.The ability to dynamically combine contents from numerous web sites and local resources,and the ability to instantly publish services worldwide have opened up entirely new possibilities for software development.In retrospect to the ten years applied research on Internetware,we have witnessed such a paradigm shift,which brings about many changes to the developmental experience of conventional web applications.Several related technologies,such as cloud computing,service computing,cyber-physical systems and social computing,have converged to address this emerging issue with emphasis on different aspects.In this paper,we first outline the requirements that the Internetware software paradigm should meet to excel at web application adaptation;we then propose a requirement model driven method for adaptive and evolutionary applications;and we report our experiences and case studies of applying it to an enterprise information system.Our goal is to provide high-level guidelines to researchers and practitioners to meet the challenges of building adaptive industrial-strength applications with the spectrum of processes,techniques and facilities provided within the Internetware paradigm.     

适用于动态软件体系结构的扩展的Z描述语言

动态软件体系结构语言已成为描述复杂软件体系结构的重要工具,然而许多描述语言都是静态的,并不能对动态软件体系进行描述。为此,对经典Z描述语言进行扩展,主要通过对构件、连接件和它们的添加以及删除来达到动态演化的目的。实例分析表明了这种扩展的可行性。     

Embracing dynamic evolution in distributed systems

Distributed systems aren't only more widespread than they used to be, but they've become more critical than ever, having moved from client-server systems to multitier heterogeneous systems. Many of these applications - such as telephone exchange systems - must be operational 24 hours a day, so shutting them down isn't a viable option for administrators who must make systemwide changes. As a system becomes larger and more complex, the likelihood of defects increases, which means a greater number of required fixes. Studies have found that nearly half the software development effort in complex distributed systems is devoted to maintenance. Furthermore, the industry currently favors iterative and incremental development approaches over the traditional waterfall approach in software engineering to flexibly handle requirements and reduce project risks by deploying smaller changes. These changes are regular and predictable. So, how can we build distributed systems to handle these kinds of changes? The answer, we argue, is dynamic evolution. From a business perspective, dynamic evolution permits frequent upgrades, which reduces the time between releases. Dynamic evolution also enhances flexibility in implementing changes to unforeseen and fluctuating business requirements. Many specialized distributed systems will benefit from factoring dynamic evolution into their designs. We can easily achieve dynamic evolution in a component-based distributed system. The abstraction of components and their connectors facilitates system structures to accommodate changes.     

A delegation-based approach for the unanticipated dynamic evolution of distributed objects

Large information systems are typically distributed and cater to several client programs, with different needs. Traditional approaches to software development and deployment cannot handle situations where (i) the needs of one client application evolve over time, diverging from the needs of others, and (ii) when the server application cannot be shutdown for maintenance. In this paper, we propose an experimental framework for the unanticipated dynamic evolution of distributed objects that enables us to: (i) extend the behavior of distributed objects during run-time, requiring no shutdown, and (ii) offer different functionalities to different applications simultaneously. In our approach, new client programs can invoke behavioral extensions to server objects that are visible only to them, while legacy applications may continue to use the non-extended versions of the server. Our approach has the advantage of: (i) requiring no changes to the host programming language or to the virtual machine, and (ii) providing a transparent programming model to the developer. In this paper, we describe the problem of unanticipated dynamic evolution of distributed objects, the principles underlying our approach, and our prototype implementations for Java and C#. We conclude by discussing related work, and the extent to which our approach can be used to support industrial strength unanticipated evolution.     

XSSRA/ADL:一种基于XML的安全需求体系结构描述语言

在开发基于Internet的大型复杂软件系统时,应该在体系结构层次上考虑业务需求和安全需求,而安全需求的体系结构描述语言(SRADL)是研究和应用安全需求体系结构的基础传统的体系结构描述语言没有专门针对安全需求的构件、连接件和体系结构风格的描述,因此,在体系结构层次上描述安全需求还比较困难提出了一种基于XML的安全需求体系结构描述语言--XSSRA/ADL,它引入了安全构件、半安全构件、安全连接件、半安全连接件等设计单元,不仅能够描述安全需求的体系结构,而且也较好地解决了软件系统中业务需求与安全需求在高层的交互和依赖关系另外,XSSRA?ADL采用数据互操作标准XML作为元语言,这使得它具有与其他ADL的互操作性,并便于支持系统的精化和演化.     

体系结构动态演化中的构件行为分析

在体系结构演化的过程中,关闭运行时系统升级的代价增高和频繁改变的业务需求使得研究者考虑动态的软件升级机制.但在体系结构的动态升级过程中,由于构件风格、功能及交互方式等方面的差别,强制的构件升级会影响系统的稳定性和正确性。从构件行为的角度考虑,采用基于Wright的软件体系结构描述语言和通信顺序进程中对于进程的描述方法,描述构件行为并在构件替换之前分析原构件和新构件间的行为特性,在演化前确认构件的行为一致性,从而保证动态升级过程的正确性和合法性,以及提高系统演化的自适应性。     

Seeding, Evolutionary Growth and Reseeding: Constructing, Capturing and Evolving Knowledge in Domain-Oriented Design Environments

We live in a world characterized by evolution—that is, by ongoing processes of development, formation, and growth in both natural and human-created systems. Biology tells us that complex, natural systems are not created all at once but must instead evolve over time. We are becoming increasingly aware that evolutionary processes are ubiquitous and critical for technological innovations as well. This is particularly true for complex software systems because these systems do not necessarily exist in a technological context alone but instead are embedded within dynamic human organizations.The Center for LifeLong Learning and Design (L3D) at the University of Colorado has been involved in research on software design and other design domains for more than a decade. We understand software design as an evolutionary process in which system requirements and functionality are determined through an iterative process of collaboration among multiple stakeholders, rather than being completely specified before system development occurs. Our research focuses on the following claims about software systems embedded within dynamic human organizations: (1) they must evolve because they cannot be completely designed prior to use, (2) they must evolve to some extent at the hands of the users, and (3) they must be designed for evolution.Our theoretical work builds upon our existing knowledge of design processes and focuses on a software process model and architecture specifically for systems that must evolve. Our theories are instantiated and assessed through the development and evolution of domain-oriented design environments (DODEs)—software systems that support design activities within particular domains and that are built specifically to evolve.     

支持动态应用集成的Web Service语义描述模型

随着B2B应用和电子商务的发展,应用系统要求在因特网环境下能够依据新的需求,快速、灵活地集成各种已有的和新添置的业务应用系统。文章通过扩展现有的WebService描述规范提出了一种支持WebService语义描述的服务资源模型,并在其基础上,通过和基于工作流的服务组合模型的结合,实现了在因特网环境下运行时的动态查找、绑定和调整的服务中介机制,有效地支持WebService的动态组合与协调     

A journey to highly dynamic, self-adaptive service-based applications

Future software systems will operate in a highly dynamic world. Systems will need to operate correctly despite of unespected changes in factors such as environmental conditions, user requirements, technology, legal regulations, and market opportunities. They will have to operate in a constantly evolving environment that includes people, content, electronic devices, and legacy systems. They will thus need the ability to continuously adapt themselves in an automated manner to react to those changes. To realize dynamic, self-adaptive systems, the service concept has emerged as a suitable abstraction mechanism. Together with the concept of the service-oriented architecture (SOA), this led to the development of technologies, standards, and methods to build service-based applications by flexibly aggregating individual services. This article discusses how those concepts came to be by taking two complementary viewpoints. On the one hand, it evaluates the progress in software technologies and methodologies that led to the service concept and SOA. On the other hand, it discusses how the evolution of the requirements, and in particular business goals, influenced the progress towards highly dynamic self-adaptive systems. Finally, based on a discussion of the current state of the art, this article points out the possible future evolution of the field.     

Relating evolving business rules to software design

In order to remain useful, it is important for software to evolve according to the changes in its business environment. Business rules, which can be used to represent both user requirements and conditions to which the system should conform, are considered as the most volatile part in today's software applications. Their changes bring high impact on both the business processes and the software itself. In this paper, we present an approach that considers business rules as an integral part of a software system and its evolution. The approach transcends the areas of requirements specification and software design. We develop the Business Rule Model to capture and specify business rules, and the Link Model to relate business rules to the metamodel level of software design elements. The aim is to improve requirements traceability in software design, as well as minimizing the efforts of software changes due to the changes of business rules. The approach is demonstrated using examples from an industrial application.