A software architecture centric self-adaptation approach for Internetware

Being one of the basic features of Internetware, self-adaptation means that the software system can monitor its runtime state and behavior and adjust them when necessary according to pre-defined policies. Focusing on the three fundamental issues of self-adaptation, including the scope, operability and trustworthiness, a software architecture （SA） centric approach for Internetware＇s self-adaptation is presented in this paper. All of the self-adaptive actions, i.e. monitoring, analyzing, planning and executing, are performed based on SA. In detail, runtime state and behavior of Internetware are represented and changed in the form of runtime soft- ware architecture. The knowledge for self-adaptation is captured, organized and reasoned in the form of SA so that automatic analysis and decision-making are achieved.     

Technical framework for Internetware: An architecture centric approach

Being a new software paradigm evolved by the Internet, Internetware brings many challenges to the traditional software methods and techniques. Sponsored by the national basic research program （973）, researchers in China have developed an architecture centric technical framework for the definition, incarnation and engineering of Internetware. First of all, a software model for Internetware is defined for what to be, including that Internetware entities should be packaged as components, behaving as agents, interoperating as services, collaborating in a structured and on demand manner, etc. Secondly, a middleware for Internetware is designed and implemented for how to be, including that Internetware entities are incarnated by runtime containers, structured collaborations are enabled by runtime software architecture, Internetware can be managed in a reflective and autonomic manner, etc. Thirdly, an engineering methodology for Internetware is proposed for how to do, including the way to develop Internetware entities and their collaborations by transforming and refining a set of software architectures which cover all the phases of software lifecycle, the way to identify and organize the disordered software assets by domain modeling, etc.     

Software Evolution for Moving into and Moving within Internetware Paradigm

Internetware has been an emerging software paradigm to best support computing in the Internet era. Internetware emphasises accommodating the open, dynamic and uncontrollable natures of Internet, which directly and indirectly relates software evolvability. This paper observes that evolving non-Internetware software into the Internetware paradigm and evolving software within Internetware will be two main research and practical issues, and hence proposes an integrated approach to address these two issues. The proposed framework is based a three-dimension structure, with System Functions, System Quality and System models as dimensions. With this framework, evolving software into internetware paradigm can be viewed mainly as changing the qualities of existing software and evolving software within Internetware paradigm can be viewed mainly as changing software functions. The involved prototype tool, working examples and experiments conducted, are used to illustrate the proposed approach.     

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.     

用抽象质量类型构建高质量网构软件

在开发基于因特网的软件系统(文中称为网构软件)时,在开发过程的各个阶段都需要考虑软件系统的多种质量属性,这样网构软件的质量才能在软件系统的规约和设计阶段进行推导和预测,从而在部署和运行阶段进一步进行评估和验证。提出了一种新的抽象概念,即抽象质量类型,将软件实体的数据状态、相关的操作、质量属性以及保证质量得以实现的环境封装在一个统一的语法单元中,从而为建模软件实体以及推导其功能和非功能属性提供了一种严格的手段。探讨了基于软件体系结构及软件交互过程的抽象质量类型的组合,这为构建高质量网构软件提供了一定的形式化基础。最后,还描出了一个系统原型来展示如何利用抽象质量类型构造网构软件,并验证和提高网构软件系统的相关质量属性。     

支持协商的网构软件体系结构行为建模与验证

针对网构软件行为中的不确定性和不完整性,提出了一种支持协商的网构软件体系结构行为建模与验证方法.在建模中,该方法借鉴了UML时序图元素表示法,并增加了建模元素支持行为的不确定与不完整建模.在验证中,除了集成广泛应用的模型检查工具Spin以提供行为模型的验证能力以外,还引入了基于反例引导的抽象-精化过程思想的协商检查,以解决不确定和不完整建模所带来的正确性验证问题.     

A model for software reuse

Software reusability is widely believed to be a key to help overcome the ongoing software crisis by improving software productivity and quality. New computer technology and the demands of an advancing society require new and more complicated software. It is unrealistic to expect that every software system can be developed solely reusing existing software; however, software reusability has proven to be a way of enhancing software productivity and quality in different organizations. It is also believed that reuse of code segments alone does not significantly reduce software development effort.By creating reuse support information while software is being developed (when the software is best known to software developers), the reuse effort for both software development and maintenance can be potentially reduced.In this paper, five types of RSI are presented: Semantic Web, Horizontal Web, Vertical Web, Syntactic Web, and Alternative Web. We collectively call these five webs a Quintet Web. The Semantic Web enables software developers to locate a software segment. The Horizontal Web provides a means to reuse a block of soflware along with other types of software from other phases of a development process. The inter-phase integration of software can be performed through this Web. The Vertical Web identifies the vertical relationship of a software block to its operational environment. The Syntactic Web locates all statements in which a variable is used. The Alternative Web provides alternative software blocks that perform an identical operation.A prototype of the Quintet Web is presented.     

Internet计算环境下的新型软件形态——网构软件(Internetware)综述

软件形态受到应用、平台和技术发展的影响而不断演化。由于Internet这一新的计算环境的普及,传统的软件形态逐渐无法适应Internet环境下的开发和应用,需要研究新的软件形态和软件技术。该文在分析软件发展历史的基础上结合相关研究说明了基于Internet环境的网构软件(Internetware)是未来软件的发展趋势,介绍了网构软件的基本特征,并说明了网构软件领域的研究问题。     

基于动态描述逻辑的网构软件系统故障诊断

提出了一种应用动态描述逻辑对被诊断系统进行分析的方法.动态描述逻辑的语法和语义非常适宜刻画系统的正常行为和异常行为.给出了算法使用动态描述逻辑的可满足性检测来测试离散事件系统的可诊断性.同时,给出了故障诊断器的构造算法.该故障诊断器通过实时地观察系统的行为完成故障诊断.以例子对算法进行了说明.     

特征模型驱动的网构软件构件组装与优化方法

面向特征的领域分析方法可为网构软件中资源的有序化提供有效支持.从领域工程的角度出发,提出一种特征模型驱动的网构软件组装与优化方法,该方法以iJackson图描述网构软件的特征模型,结合软件体系结构特点,分析了将特征模型转换为面向业务构件、基于工作流图技术的组合模型的机制,通过应用图论方法,将组合模型建模为以领域特征簇为中心的构件组装结构图,围绕面向多目标需求的QoS模型,建立了Internet环境下网构软件构件组装问题的数学模型,提出了一种基于蚁群优化算法的全局优化方法.最后,以网上书店系统为倒,介绍了仿真实验过程,并说明了方法的有效性和可行性.     

基于场景自动机的网构软件演化

网构软件是网络开放、动态和多变环境下软件系统基本形态的一种抽象,其演化性要求软件能根据应用需求和运行环境变化而动态演化。引入了软件需求工程中场景的概念,但不同的是不把场景作为一种静态的记录来使用,而是把场景作为一种动态记录来描述软件的动态演化特征。给出了场景的形式化定义及其互补、等价、子集等关系描述,提出了基于场景自动机的网构软件演化方法。软件的性质和行为可以由一系列应用场景来展现,系统的演化通过场景自动机来体现,这为系统自适应演化提供了一种新的解决方法,并支持系统更大粒度的复用。     

A software architecture centric engineering approach for Internetware

As a new software paradigm evolved by the Internet, Internetware brings many challenges for the traditional software development methods and techniques. Though architecture-based component composition (ABC) approach is originated in the traditional software paradigm, it supports the engineering of Internetware effectively due to its philosophy, rationales and mechanisms. ABC has three major contributions to the en- gineering of Internetware in detail. First, the feature oriented domain modeling method can structure the “disordered”“software entities” to “ordered Internetware” bottom-up in the problem space. Second, the architecture centric design and analysis method can support the development of self-adaptive Internetware. Third, the component operating platform is a reflective and self-adaptive middleware that not only provides Internetware with a pow- erful and flexible runtime infrastructure but also enables the self-adaptation of the structure and individual entities of Internetware.     

网构软件数据语用的一种动态支撑方法

网构软件不确定的数据需求导致了其数据语用(data pragmatics,简称DP)的不确定性,进而要求数据语用的支撑机制具备动态适应能力,即应用的对象属性与数据表之间的对应关系可以按需动态地创建、更新、删除.针对当前持久化技术缺乏数据语用的动态适应性问题,提出了一种基于对象/关系映射的数据语用动态支撑方法POD(persistence on demand),并且在主流ORM(object/relational mapping)框架的基础上实现了一个遵循POD的持久化框架的原型系统.     

上下文感知计算的支撑环境及其参考实现

以网构软件为背景,给出了一个支持上下文情境感知的支撑环境设计框架,重点描述了该框架的一种基于OSGi的参考实现方法;通过一个案例描述了该系统的应用过程,以说明其有效性。     

网构软件的随机性资源自适应性的形式化分析与验证

因特网上的资源具有不确定性、随机性,需要考虑如何保证网构软件系统在运行中满足资源需求。使用随机性资源接口自动机对软件构件的行为进行形式化建模,并使用随机性资源接口自动机网络描述构件组装系统的组合行为;在资源不确定的情况下,检验组合系统是否满足资源约束,并提出基于可达图的相应算法。给出了一个实例网上书店系统,并用模型检测工具Spin验证了模型的正确性。     

网构软件体系结构代数模型

由于网络化软件的规模和复杂程度的不断增加,设计可伸缩的软件体系结构,开发可演化的软件系统遇到了挑战.挑战之一是很难把软件模型与原系统说明区分开来,使得软件系统的可演化性受到限制.一个有效的途径是建立可范用软件体系结构的抽象模型,指导网构软件设计,从而提高软件模型的概括能力和可伸缩能力.本文提出一种网构软件体系结构代数模型,其中一个创新思想是把网构连接子解释成网构变量的运算.结合代数学方法和软件实现技术,定义了6种网构连接运算,所有运算是对连接子的代数抽象,因此软件体系结构的抽象表达能力得到了加强.为了展示提出代数模型的建模与分析辅助作用,介绍了一个基于代数模型的网构软件设计与演化的案例研究.     

SelfTrust: leveraging self-assessment for trust inference in Internetware

Internetware is envisioned as a new software paradigm for software development in platforms such as the Internet.The reliability of the developed software becomes a key challenge due to the open,dynamic and uncertain nature of such environment.To make the development more reliable,it is necessary to evaluate the trustworthiness of the resource providers or potential working partners.To this end,we propose a novel trust inference approach to evaluating the trustworthiness of potential partners to guide the software development in Internetware.The main insight of our approach is to employ the self-assessment information in order to improve the trust inference accuracy.Especially,we frst extend the balance theory and the status theory from social science to incorporate self-assessment,and then propose a machine learning framework to extract several features from the extended theories and infer trustworthiness scores based on these features.Experimental results on a real software developer network show that the self-assessment information truly helps to improve the accuracy of trust inference,and the proposed SelfTrust model is more accurate than other state-of-the-art methods.     

基于贝叶斯网络的网构软件可信性评估模型

对于运行在开放、动态、难控的互联网环境的网构软件,其可信性评估是一个重要课题,但目前大量研究中可信性计算多是基于黑盒的,没有深入考虑系统结构,且评价指标过于单一.因此,提出了一个基于贝叶斯网络的网构软件可信性评估模型.该模型通过对网构软件进行结构分析,根据其结构模式,建立多层的网构软件可信性评估指标体系.基于贝叶斯网络采用自底向上逐层分析计算的方法,对网构软件的各组成实体及其系统整体的多方面可信性指标进行评估,形成统一的可信性结果,并使用客观数据对其进行修正.实验证明,该模型可以明确、客观地对网构软件的可信性进行评估,并能够对网构软件的设计、开发和部署提供帮助.