特征模型中非功能需求建模初探

在需求模型中准确、完整地规约与非功能需求(NFR)相关的语义是实现NFR的前提,也是需求建模的难点.本文探讨了特征模型中NFR的建模方法,该方法显式区分功能和非功能特征,根据精化关系将处于不同抽象层次上的非功能特征组织成树状结构,支持对NFR的系统化处理.该方法扩展特征模型以显式描述特定于NFR的语义,还给出了基于知识库(特别是中间件特征模型构成的知识库)识别并精化NFR的过程.该方法在奥运信息系统建模中得到了应用.     

面向嵌入式产品线的非功能特征模型

非功能特征直接影响嵌入式软件产品的质量,而传统特征模型未对嵌入式软件产品线的非功能特征细致定义。面向嵌入式产品线,提出一种非功能特征模型。首先定义特征的元模型,融合嵌入式领域扩展特征种类,生成非功能特征模型即非功能特征对象、非功能特征对象属性、非功能特征对象关系三元组,并规范其建模过程,从而解决无法清晰定义的问题。最后采用VP-UML工具对呼吸机时间量建模,验证模型的可用性,生成可扩展的基本代码,提高了需求分析效率。     

基于特征组合的软件需求建模

需求建模在需求工程中起着重要的作用。为了提高软件需求建模的效率和质量,提出一种基于特征组合的软件需求建模方法。首先,将特征分为功能性特征和非功能性特征;其次,形式化定义功能性特征的各个部件,包括原子功能性特征和复合功能性特征;第三,把功能性特征之间的特征组合抽象为特征运算,并提出了23条特征运算的公理;第四,形式化定义非功能性特征并通过其作用域把功能性特征和非功能性特征统一为软件需求模型;最后,给出了基于特征组合的软件需求建模过程。     

基于模型对比和组合的软件产品线领域需求建模

软件产品线作为系统化的软件复用方式,可以提高软件的开发效率和质量.软件产品线变化性建模是软件产品线的关键技术,通过建立变化性模型以记录软件产品线成员产品的共性和变化性.目前的软件产品线变化性建模方法大都通过领域专家进行分析建立,这种方法过度依赖于领域专家的分析能力,在系统规模较小的情况下,变化性分析比较容易,但是如果系统规模变大,则系统的规模对于变化性分析的影响会越来越大.文中提出一种半自动的软件产品线领域需求建模方法,基于关注点分离的思路,利用特征模型表示软件产品线中系列产品的不同方面的特征信息,通过特征模型的对比和组合实现领域需求模型的构建.为有效地实现特征模型对比与组合,文中提出一种基于标记和结构的特征模型对比方法,同时,文中实现了基于约束的特征模型组合.基于公开的特征模型,文中对提出的方法进行了验证,实验结果表明,文中提出的领域需求建模方法能够在一定准确率的情况下有效地实现领域需求模型的构建.     

非功能需求的结构化定义以及概念性追踪管理框架

针对需求工程中非功能需求概念非常模糊甚至相互矛盾、非功能需求与其他非功能需求及功能需求之间的关系繁复而难以分析和建模、非功能需求与设计阶段制品之间的追踪关系模糊而不易记录和维护等问题,分析了与非功能需求相关的概念在需求分析阶段和体系结构设计阶段的表现形式,给出了一个结构化的非功能需求定义;规范了不同类型需求之间的各种复杂关系,建立了一个跨越分析和设计阶段的概念性非功能需求追踪管理框架,规范了需求分析和体系结构设计阶段与非功能需求相关的概念和制品之间的关系。提出的结构化定义以及概念性追踪管理框架明确地刻画了非功能需求概念的外延,为简化需求模型以及进一步研制系统化、实用化的非功能需求建模及追踪管理技术奠定了理论基础。     

基于XML的软件非功能需求建模研究

本文针对当前软件设计中非功能需求描述不清楚、难以实现等问题,对软件非功能需求建模方法进行了研究,提出了一个基于XML的软件非功能需求建模方法,构建了一个软件非功能需求元模型,该模型主要包括属性、约束和实现方法三个数据单元.在此基础上,利用XML Schema定义了软件非功能需求的数据模型结构,以一个通信系统的非功能需求建模为例说明了本模型的建模过程和方法,结果表明,该建模方法有助于设计人员对软件非功能需求进行清楚的定义.     

基于特征分解模式的软件产品线参考设计方法

基于特征的领域分析与建模技术是软件产品线开发中较为主流的需求建模方法,为描述产品线共性和可变性及其之间的关系提供了良好的支持。然而在现有特征模型基础上,如何指导系统开发人员进行软件系统的详细设计是亟待解决的问题。该问题主要体现在特征之间的结构与语义关系,以及特征的可变性如何映射为合理的系统设计模型这两个方面。针对上述问题,提出一种基于特征分解模式的软件产品线参考设计方法。该方法为特征模型中具有不同结构、不同语义的特征分解模式提供参考的详细设计方案,并提出相关聚类准则以支持对应全局特征模型的设计模型优化。最后,通过成绩录入软件产品线对该方法的有效性进行验证。     

基于描述逻辑的特征语义建模及验证

在软件产品线方法中,特征模型已被广泛用于获取领域需求以支持软件复用.但在一定程度上,各种方法对刻画特征模型以及特征之间约束关系存在语义上的冗余和混乱,不能有效对特征模型进行验证,也限制各种不同特征建模方法之间特征信息的共享.采用描述逻辑刻画了特征模型中的特征类、特征间关系与约束等方面,定义了特征间互斥、需要等约束的规则集合,用于对知识库中的语义特征模型实例进行一致性、完整性验证.并结合一个具体领域,对基于描述逻辑的特征建模及推理验证进行了详细论述.此研究对于领域特征模型的语义建模与验证、支持领域模型共享具有一定的指导作用.     

基于UML的软件产品线建模方法研究

软件产品线方法是一种面向特定领域的、大规模、大粒度的软件复用技术。文章简要介绍了基于UML的软件产品线建模方法。由于软件产品线对于产品线成员公共性和变化性的特殊关注,其用例模型、交互模型、状态模型、静态模型、特征模型和单一软件系统相比都有所区别。文章对各种模型进行描述的同时,以报业排版软件产品线样张打印功能为例,进行具体说明。     

特征建模方法研究

在领域工程中,特征模型描述了领域需求之间的关系,在共性和特性之间进行区别,在复杂软件系统设计和实现中扮演了重要的角色.介绍了特征建模方法的起源和发展,分析和比较了两种典型的特征定义,从特征模型体系结构,特征模型的表现、特征变化性和组合规则、特征建模工具和特征模型的应用等方面阐述了特征建模领域的若干研究活动,介绍了特征建模方法的主要研究现状以及研究方向.     

Feature-Oriented Nonfunctional Requirement Analysis for Software Product Line

Domain analysis in software product line (SPL) development provides a basis for core assets design and implementation by a systematic and comprehensive commonality/variability analysis. In feature-oriented SPL methods, products of the domain analysis are domain feature models and corresponding feature decision models to facilitate application-oriented customization. As in requirement analysis for a single system, the domain analysis in the SPL development should consider both functional and nonfunctional domain requirements. However, the nonfunctional requirements (NFRs) are often neglected in the existing domain analysis methods. In this paper, we propose a context-based method of the NFR analysis for the SPL development. In the method, NFRs are materialized by connecting nonfunctional goals with real-world context, thus NFR elicitation and variability analysis can be performed by context analysis for the whole domain with the assistance of NFR templates and NFR graphs. After the variability analysis, our method integrates both functional and nonfunctional perspectives by incorporating the nonfunctional goals and operationalizations into an initial functional feature model. NFR-related constraints are also elicited and integrated. Finally, a decision model with both functional and nonfunctional perspectives is constructed to facilitate application-oriented feature model customization. A computer-aided grading system (CAGS) product line is employed to demonstrate the method throughout the paper. This work is supported by the National Natural Science Foundation of China under Grant Nos. 60703092 and 90818009, the National High Technology Research and Development 863 Program of China under Grant No. 2007AA01Z125.     

Feature-oriented stigmergy-based collaborative requirements modeling: an exploratory approach for requirements elicitation and evolution based on web-enabled collective intelligence

Compared with traditional software applications, the requirements problem of Internetware applications exhibits a set of new characteristics that cannot be resolved by traditional engineer-centered face-to-face requirements methods. In this paper, we present an exploratory approach to the requirements elicitation and evolution problem of Internetware applications, based on the concept of web-enable collective intelligence, to accommodate the situation of large-scale user communities of Internetware applications with diverse and constantly evolving requirements. In particular, we propose a feature-oriented stigmergy-based collaborative requirements modeling method that combines feature-oriented requirements modeling with web-enabled stigmergy-based collaboration to support large-scale collaborative requirements eliciting and evolving activities for Internetware applications. Two experiments are introduced to show the feasibility and effectiveness of this approach.     

Control case approach to record and model non-functional requirements

While the functional requirements of a system can be effectively modeled through the use case driven approach, there is no standard or de facto method for modeling non-functional requirements (NFR) of the system architecture. Often such requirements are dealt with in a reactive manner, rather than proactively. Yet increasingly a contributing factor in project difficulty and failure are the NFR imposed on the solution architecture. This paper outlines a control case approach to record and model NFR. This technique enables the control case to represent the NFR from different perspectives, most typically the various operating conditions. We also propose an extension to the “4 + 1” view model for depicting software architecture by adding the control case view. In addition, a detailed control case modeling example is illustrated to demonstrate how these techniques may be applied during development. Taken together, we suggest that the combination of both the use case and control case views thus reflects the complete requirements across the collective system life cycle views: design, process, implementation and deployment.     

Detecting,classifying, and tracing non-functional software requirements

In this paper, we describe a novel unsupervised approach for detecting, classifying, and tracing non-functional software requirements (NFRs). The proposed approach exploits the textual semantics of software functional requirements (FRs) to infer potential quality constraints enforced in the system. In particular, we conduct a systematic analysis of a series of word similarity methods and clustering techniques to generate semantically cohesive clusters of FR words. These clusters are classified into various categories of NFRs based on their semantic similarity to basic NFR labels. Discovered NFRs are then traced to their implementation in the solution space based on their textual semantic similarity to source code artifacts. Three software systems are used to conduct the experimental analysis in this paper. The results show that methods that exploit massive sources of textual human knowledge are more accurate in capturing and modeling the notion of similarity between FR words in a software system. Results also show that hierarchical clustering algorithms are more capable of generating thematic word clusters than partitioning clustering techniques. In terms of performance, our analysis indicates that the proposed approach can discover, classify, and trace NFRs with accuracy levels that can be adequate for practical applications.     

Extending the desirability function to account for variability measures in univariate and multivariate response experiments

One technique used frequently among quality practitioners seeking solutions to multi-response optimization problems is the desirability function approach. The technique involves modeling each characteristic using response surface designs and then transforming the characteristics into a single performance measure. The traditional procedure, however, calls for estimating only the mean response; the variability among the characteristics is not considered. Furthermore, the approach typically relies on the accuracy of second-order polynomials in its estimation, which are not always suitable. This paper, in contrast, proposes a methodology that utilizes higher-order estimation techniques and incorporates the concepts of robust design to account for process variability. Several examples are provided to illustrate the effectiveness of the proposed methodology.     

基于故障配置的故障树生成

故障树分析是提高系统安全性和可靠性的有效方法。传统的人工故障树生成方式难以解决当前系统的庞大规模与复杂性的问题,且容易出错。为此,提出基于故障配置的故障树生成方法,引入软件产品线的可变性管理,用于系统故障建模与形式化分析。首先,定义故障特征图模型用于刻画系统故障间的约束关系,基于Kripke结构定义故障标记迁移系统来描述系统的行为;然后,基于模型的语义建立通过模型检测生成故障树的过程;最后,通过时序逻辑描述系统安全属性,利用模型检测工具SNIP验证安全属性进而生成故障树。案例研究验证了该方法的有效性。     

Toward automated feature model configuration with optimizing non-functional requirements

ContextA software product line is a family of software systems that share some common features but also have significant variabilities. A feature model is a variability modeling artifact, which represents differences among software products with respect to the variability relationships among their features. Having a feature model along with a reference model developed in the domain engineering lifecycle, a concrete product of the family is derived by binding the variation points in the feature model (called configuration process) and by instantiating the reference model.ObjectiveIn this work we address the feature model configuration problem and propose a framework to automatically select suitable features that satisfy both the functional and non-functional preferences and constraints of stakeholders. Additionally, interdependencies between various non-functional properties are taken into account in the framework.MethodThe proposed framework combines Analytical Hierarchy Process (AHP) and Fuzzy Cognitive Maps (FCM) to compute the non-functional properties weights based on stakeholders’ preferences and interdependencies between non-functional properties. Afterwards, Hierarchical Task Network (HTN) planning is applied to find the optimal feature model configuration.ResultOur approach improves state-of-art of feature model configuration by considering positive or negative impacts of the features on non-functional properties, the stakeholders’ preferences, and non-functional interdependencies. The approach presented in this paper extends earlier work presented in [1] from several distinct perspectives including mechanisms handling interdependencies between non-functional properties, proposing a novel tooling architecture, and offering visualization and interaction techniques for representing functional and non-functional aspects of feature models.Conclusionour experiments show the scalability of our configuration approach when considering both functional and non-functional requirements of stakeholders.     

一种可复用的插件粒度划分方法

基于应用程序功能来划分插件的传统方法不能快速适应可复用的插件设计要求。针对这一问题,提出一种基于领域分析的插件划分方法。该方法采用了多分层插件软件模式,重点突出软件体系结构中的领域层,并运用面向特征的领域建模技术针对插件软件应用系统实现领域特征的共性和个性的划分。通过应用案例证明,该方法可以有效地降低插件模块间的耦合性,提高复用粒度。     

一种面向特征的领域模型及其建模过程

特征模型作为捕获领域需求的重要模型已被现阶段的主流领域工程方法所接受,但这些方法缺乏对特征模型组织框架的细致研究和说明,在一定程度上导致了特征模型在表现形式上的冗余性和混乱性,也使得领域分析人员在实践中很难有效地进行领域建模活动.从特征模型的基本组织结构、变化性的表现方式和限制机制、变化性的绑定时间等方面对特征模型的组织框架及剪裁机制进行了统一、抽象的描述.在考察服务、用例(use case)、功能、行为特点等不同类型的特征及其相互关系的基础上,给出了一种特征模型的具体形式,并结合具体的领域,对其建模过程进行了详细论述.此项研究对于领域建模活动的成功实施具有一定的指导作用.