A framework for analysis and design of software reference architectures

Context

A software reference architecture is a generic architecture for a class of systems that is used as a foundation for the design of concrete architectures from this class. The generic nature of reference architectures leads to a less defined architecture design and application contexts, which makes the architecture goal definition and architecture design non-trivial steps, rooted in uncertainty.

Objective

The paper presents a structured and comprehensive study on the congruence between context, goals, and design of software reference architectures. It proposes a tool for the design of congruent reference architectures and for the analysis of the level of congruence of existing reference architectures.

Method

We define a framework for congruent reference architectures. The framework is based on state of the art results from literature and practice. We validate our framework and its quality as analytical tool by applying it for the analysis of 24 reference architectures. The conclusions from our analysis are compared to the opinions of experts on these reference architectures documented in literature and dedicated communication.

Results

Our framework consists of a multi-dimensional classification space and of five types of reference architectures that are formed by combining specific values from the multi-dimensional classification space. Reference architectures that can be classified in one of these types have better chances to become a success. The validation of our framework confirms its quality as a tool for the analysis of the congruence of software reference architectures.

Conclusion

This paper facilitates software architects and scientists in the inception, design, and application of congruent software reference architectures. The application of the tool improves the chance for success of a reference architecture.     

A systematic review of domain analysis solutions for product lines

Domain analysis is crucial and central to software product line engineering (SPLE) as it is one of the main instruments to decide what to include in a product and how it should fit in to the overall software product line. For this reason many domain analysis solutions have been proposed both by researchers and industry practitioners. Domain analysis comprises various modeling and scoping activities. This paper presents a systematic review of all the domain analysis solutions presented until 2007. The goal of the review is to analyze the level of industrial application and/or empirical validation of the proposed solutions with the purpose of mapping maturity in terms of industrial application, as well as to what extent proposed solutions might have been evaluated in terms of usability and usefulness. The finding of this review indicates that, although many new domain analysis solutions for software product lines have been proposed over the years, the absence of qualitative and quantitative results from empirical application and/or validation makes it hard to evaluate the potential of proposed solutions with respect to their usability and/or usefulness for industry adoption. The detailed results of the systematic review can be used by individual researchers to see large gaps in research that give opportunities for future work, and from a general research perspective lessons can be learned from the absence of validation as well as from good examples presented. From an industry practitioner view, the results can be used to gauge as to what extent solutions have been applied and/or validated and in what manner, both valuable as input prior to industry adoption of a domain analysis solution.     

根据系统需求决策软件产品线体系结构

软件生产线是实现软件复用的有效手段.由于需求的复杂性和软件体系结构风格的多样性以及其他因素的影响,如何由现实的系统需求得到一个合理的软件生产线体系结构已经成为一个亟待解决的问题.提出基于需求建立系统体系结构的框架-FM(Fuzzy method)过程,包括基于目标和场景模型的逻辑组件的识别,应用Fuzzy比较方法计算逻辑组件的重要度,定量的系统特性分析和建立体系结构模型四个主要的步骤.以综合考务系统项目为例说明了这种方法的有效性和实际的可操作性.     

Secure Tropos framework for software product lines requirements engineering

Security and requirements engineering are two of the most important factors of success in the development of a software product line (SPL). Goal-driven security requirements engineering approaches, such as Secure Tropos, have been proposed as a suitable paradigm for elicitation of security requirements and their analysis on both a social and a technical dimension. Nevertheless, goal-driven security requirements engineering methodologies are not appropriately tailored to the specific demands of SPL, while on the other hand specific proposals of SPL engineering have traditionally ignored security requirements. This paper presents work that fills this gap by proposing “SecureTropos-SPL” framework.     

一种面向特征的软件产品线非功能需求建模方法

分析传统非功能需求定义的不足,基于需求分析阶段的系统抽象—"需求模型"重新定义非功能需求,规范并简化功能需求与非功能需求之间的关系。扩展面向特征的软件产品线建模方法,在特征模型中显式地建模功能需求、非功能需求、非功能需求类型以及它们之间的相互关系,沿用传统特征模型中固有的变化性建模机制建模并管理非功能需求的变化性,显式地复用与非功能需求相关的建模知识和资产,为进一步研究定量评估产品线变体质量的新技术奠定基础。设计了一个基于多视图的特征建模方法,指导开发者在迭代的过程中建模非功能需求和功能需求,支持关注点分离和模型的复杂性管控。实现了工具原型并进行了实例验证。     

Capturing quality requirements of product family architecture

Software quality is one of the major issues with software intensive systems. Moreover, quality is a critical success factor in software product families exploiting shared architecture and common components in a set of products. Our contribution is the QRF (Quality Requirements of a software Family) method, which explicitly focuses on how quality requirements have to be defined, represented and transformed to architectural models. The method has been applied to two experiments; one in a laboratory environment and the other in industry. The use of the QRF method is exemplified by the Distribution Service Platform (DiSeP), the laboratory experiment. The lessons learned are also based on our experiences of applying the method in industrial settings.     

软件产品线需求过程和方法浅论

软件产品线作为一种新型的复用技术,如何准确获取产品线需求具有更为重要的意义.为此,在介绍软件产品线工程原理和实践的基础上,对产品线需求过程框架,以及如何利用PR-Context矩阵方法来来客观确定产品线需求的共性与可变性进行了深入分析,并且讨论了如何通过需求层次和维度划分以降低产品线需求分析的复杂性,对于产品线需求工程实践具有一定的指导作用.     

Pseudo software: A mediating instrument for modeling software requirements

A new synthesis of software requirements models called pseudo software is proposed with the aim to cut requirements-related errors. Pseudo software achieves this aim by serving as a mediating instrument to empower stakeholders to participate in requirements elicitation and validation through model construction and manipulation, and to provide guidance to the development team to correctly interpret the requirements in the downstream development activities. Pseudo software obtains its traits as a mediating instrument through the choice of requirements information bits and the use of multimodal representations with tool support to integrate the requirements. Using historical data of fifty projects in the enterprise computing domain, pseudo software is shown to effectively cut the requirements-related errors committed by both the customer and the development team.     

Reconciling software requirements and architectures with intermediate models

Little guidance and few methods are available for the refinement of software requirements into an architecture satisfying those requirements. Part of the challenge stems from the fact that requirements and architectures use different terms and concepts to capture the model elements relevant to each. In this paper we will present CBSP, a lightweight approach intended to provide a systematic way of reconciling requirements and architectures using intermediate models. CBSP leverages a simple set of architectural concepts (components, connectors, overall systems, and their properties) to recast and refine the requirements into an intermediate model facilitating their mapping to architectures. Furthermore, the intermediate CBSP model eases capturing and maintaining arbitrarily complex relationships between requirements and architectural model elements, as well as among CBSP model elements. We have applied CBSP within the context of different requirements and architecture definition techniques. We leverage that experience in this paper to demonstrate the CBSP method and tool support using a large-scale example.     

Managing requirements conflicts in software product lines: A goal and scenario based approach

The product line approach is recognized as a successful approach to reuse in software development. However, in many cases, it has resulted in interactions between requirements and/or features. Interaction detection, especially conflict detection between requirements has become more challenging. Thus, detecting conflicts between requirements is essential for successful product line development. Formal methods have been proposed to address this problem, however, they are hard to understand by non-experts and are limited to restricted domains. In addition, there is no overall process that covers all the steps for managing conflicts. We propose an approach for systematically identifying and managing requirements conflicts, which is based on requirements partition in natural language and supported by a tool. To demonstrate its feasibility, the proposed approach has been applied to the home integration system (HIS) domain and the results are discussed.     

A formal framework for software product lines

ContextA Software Product Line is a set of software systems that are built from a common set of features. These systems are developed in a prescribed way and they can be adapted to fit the needs of customers. Feature models specify the properties of the systems that are meaningful to customers. A semantics that models the feature level has the potential to support the automatic analysis of entire software product lines.ObjectiveThe objective of this paper is to define a formal framework for Software Product Lines. This framework needs to be general enough to provide a formal semantics for existing frameworks like FODA (Feature Oriented Domain Analysis), but also to be easily adaptable to new problems.MethodWe define an algebraic language, called SPLA, to describe Software Product Lines. We provide the semantics for the algebra in three different ways. The approach followed to give the semantics is inspired by the semantics of process algebras. First we define an operational semantics, next a denotational semantics, and finally an axiomatic semantics. We also have defined a representation of the algebra into propositional logic.ResultsWe prove that the three semantics are equivalent. We also show how FODA diagrams can be automatically translated into SPLA. Furthermore, we have developed our tool, called AT, that implements the formal framework presented in this paper. This tool uses a SAT-solver to check the satisfiability of an SPL.ConclusionThis paper defines a general formal framework for software product lines. We have defined three different semantics that are equivalent; this means that depending on the context we can choose the most convenient approach: operational, denotational or axiomatic. The framework is flexible enough because it is closely related to process algebras. Process algebras are a well-known paradigm for which many extensions have been defined.     

A model-driven approach for the derivation of architectural requirements of software product lines

The alignment of the software architecture and the functional requirements of a system is a demanding task because of the difficulty in tracing design elements to requirements. The four-step rule set (4SRS) is a unified modeling language (UML)-based model-driven method for single system development which provides support to the software architect in this task. This paper presents an evolution of the 4SRS method aimed at software product lines. In particular, we describe how to address the transformation of functional requirements (use cases) into component-based requirements for the product line architecture. The result is a UML-based model-driven method that can be applied in combination with metamodeling tools such as the eclipse modeling framework (EMF) to derive the architecture of software product lines. We present our approach in a practical way and illustrate it with an example. We also discuss how our proposals are related to the work of other authors.     

A model-driven traceability framework for software product lines

Software product line (SPL) engineering is a recent approach to software development where a set of software products are derived for a well defined target application domain, from a common set of core assets using analogous means of production (for instance, through Model Driven Engineering). Therefore, such family of products are built from reuse, instead of developed individually from scratch. SPL promise to lower the costs of development, increase the quality of software, give clients more flexibility and reduce time to market. These benefits come with a set of new problems and turn some older problems possibly more complex. One of these problems is traceability management. In the European AMPLE project we are creating a common traceability framework across the various activities of the SPL development. We identified four orthogonal traceability dimensions in SPL development, one of which is an extension of what is often considered as “traceability of variability”. This constitutes one of the two contributions of this paper. The second contribution is the specification of a metamodel for a repository of traceability links in the context of SPL and the implementation of a respective traceability framework. This framework enables fundamental traceability management operations, such as trace import and export, modification, query and visualization. The power of our framework is highlighted with an example scenario.     

Managing requirements inter-dependency for software product line derivation

Software Product Line Engineering (SPLE) can reduce software development costs, reduce time to market and improve product quality. A software product line is a set of software products sharing a set of common features but containing variation points. Successful SPLE requires making selection decisions at variation points effectively and efficiently. A significant challenge is how to identify, represent and manage the inter-dependency of selection decisions for requirements. We developed the concept of a meta-model for requirement decision models to bring formalism and consistency to the structure and to model inter-dependencies between requirement selection decisions. Here we present a meta-model for requirement selection decisions that includes inter-dependencies and we use a mobile phone worked example to illustrate our approach. To support our method, we developed two separate tools, V-Define (for domain decision model construction) and V-Resolve (for new product derivation). Finally the results of a metal processing product line case study using the tools are described.

A Knowledge-Based Software Engineering Environment for reusable software requirements and architectures

This paper describes a prototype Knowledge-Based Software Engineering Environment used to demonstrate the concepts of reuse of software requirements and software architectures. The prototype environment, which is application-domain independent, is used to support the development of domain models and to generate target system specifications from them. The prototype environment consists of an integrated set of commercial-off-the-shelf software tools and custom developed software tools.The concept of reuse is prevalent at several levels of the domain modeling method and prototype environment. The environment itself is domain-independent thereby supporting the specification of diverse application domain models. The domain modeling method specifies a family of systems rather than a single system; features characterize the variations in functional requirements supported by the family and individual family members are specified by the features they are to support. The knowledge-based approach to target system generation provides the rules for generating target system specifications from the domain model; target system specifications, themselves, may be stored in an object repository for subsequent retrieval and reuse.     

基于领域需求结构化描述的自动分析建模方法

软件需求描述和需求分析建模一直以来是需求工程的重要工作,且存在紧密的关联,自动化需求分析建模与验证需要以规范的需求描述为基础。提出基于领域需求的结构化描述的自动分析建模方法,通过对系统整体按照一定的组织结构进行描述,描述句式采用富含语义的句型和普通句型相结合的方式,运用自然语言处理相关技术,通过预定义的转换规则对结构化描述下的需求文本进行建模元素识别,实现自动化的建模,最终生成UML图形化分析结果。     

A trace metamodel proposal based on the model driven architecture framework for the traceability of user requirements in data warehouses

The complexity of the data warehouse (DW) development process requires to follow a methodological approach in order to be successful. A widely accepted approach for this development is the hybrid one, in which requirements and data sources must be accommodated to a new DW model. The main problem is that we lose the relationships between requirements, elements in the multidimensional (MD) conceptual models and data sources in the process, since no traceability is explicitly specified. Therefore, this hurts requirements validation capability and increases the complexity of Extraction, Transformation and Loading processes. In this paper, we propose a novel trace metamodel for DWs and focus on the relationships between requirements and MD conceptual models. We propose a set of Query/View/Transformation rules to include traceability in DWs in an automatic way, allowing us to obtain a MD conceptual model of the DW, as well as a trace model. Therefore, we are able to trace every requirement to the MD elements, further increasing user satisfaction. Finally, we show the implementation in our Lucentia BI tool.     

Kumbang: A domain ontology for modelling variability in software product families

Variability is the ability of a system to be efficiently extended, changed, customised or configured for use in a particular context. There is an ever-growing demand for variability of software. Software product families are an important means for implementing software variability. We present a domain ontology called Kumbang for modelling the variability in software product families. Kumbang synthesises previous approaches to modelling variability in software product families. In addition, it incorporates modelling constructs developed in the product configuration domain for modelling the variability in non-software products. The modelling concepts include components and features with compositional structure and attributes, the interfaces of components and connections between them, and constraints. The semantics of Kumbang is rigorously described using natural language and a UML profile. We provide preliminary proof of concept for Kumbang: the domain ontology has been provided with a formal semantics by implementing a translation into a general-purpose knowledge representation language with formal semantics and inference support. A prototype tool for resolving variability has been implemented.