一种基于面向侧面技术的并发式软件建模方法

基于面向侧面（Aspect-Oriented）技术及统一建模语言状态图提出了并发式软件系统开发过程中横切特性的建模方法。本方法将并发软件系统的业务逻辑和横切行为分别封装到复合状态的不同正交区域中，并通过事件广播机制反映二者的交互关系。同时，以模块化的状态迁移系统 （Modular Transition System）作为基本计算模型，对该建模方法进行形式化描述，给出了模型元素及建模过程的精确语义。实例研究表明，该方法在并发软件设计阶段实现了横切关注点的分离策略，并使得系统模型具有松耦合、适应性和可跟踪性的优点。     

Integrating visual goal models into the Rational Unified Process

The Rational Unified Process is a comprehensive process model that is tailorable, provides templates for the software engineering products, and integrates the use of the Unified Modeling Language (UML); it is rapidly becoming a de facto standard for developing software. The process supports the definition of requirements at multiple levels. Currently, the early requirements, or goals, are captured in a textual document called the Vision Document, as the UML does not include a goal modeling diagram. The goals are subsequently refined into software requirements, captured in UML Use Case Diagrams. Given the well documented advantages of visual modeling techniques in requirements engineering, including the efficient communication and understanding of complex information among numerous diverse stakeholders, the need for an enhanced version of the Vision Document template which supports the visual modeling of goals is identified. Here, an Enhanced Vision Document is proposed which integrates two existing visual goal models: AND/OR Graph for functional goals and Softgoal Interdependency Graph for non-functional goals. A specific approach to establishing traceability relationships from the goals to the Use Cases is presented. Tool support has been developed for the Enhanced Vision Document template; the approach is illustrated using an example system called the Quality Assurance Review Assistant Tool.     

计算机实践向理论的回归

软件工程研究软件开发过程所需的模型、方法和工具。UML是软件工程实践中的重要工具,它可以对软件进行规约、可视化、构造和建档。本文以UML的状态图为例,讨论了其在十字路口的信号灯的控制中的应用,指出了其在软件需求分析中的建模作用,并揭示了软件工程与计算机科学之间的关系。最后,指出了当今软件工程的发展与实践是在向 向计算机科学理论回归,从而作为计算机科学的理论基础的离散数学对实践的指导作用就显而易见了。     

基于UML的软件Markov链使用模型构造研究

软件统计测试要求基于软件使用模型产生测试例对软件系统进行测试,并根据测试结果评价软件可靠性,是高可靠软件测试的重要组成部分.由于统一建模语言(unified modeling language,简称UML)已经成为事实上的面向对象标准建模语言,因此,从软件UML模型构造软件使用模型就成为面向对象软件统计测试的关键.为此,定义了加入统计测试约束的UML用例图、序列图以及用例执行顺序关系,为基于UML的软件统计测试提供了一个形式化描述基础.在此基础上,给出一个从软件UML模型构造软件Markov链使用模型的算法,并给出了自动化支持工具UMGen的类图结构,基于一个卫星控制系统,说明了所提出方法的有效性.     

A logical approach to systems engineering artifacts: semantic relationships and dependencies beyond traceability—from requirements to functional and architectural views

Not only system assurance drives a need for semantically richer relationships across various artifacts, work products, and items of information than are implied in the terms “trace and traceability” as used in current standards and textbooks. This paper deals with the task of working out artifacts in software and system development, their representation, and the analysis and documentation of the relationships between their logical contents—herein referred to as tracing and traceability; this is a richer meaning of traceability than in standards like IEEE STD 830. Among others, key tasks in system development are as follows: capturing, analyzing, and documenting system-level requirements, the step to functional system specifications, the step to architectures given by the decomposition of systems into subsystems with their connections and behavioral interactions. Each of these steps produces artifacts for documenting the development, as a basis for a specification and a design rationale, for documentation, for verification, and impact analysis of change requests. Crucial questions are how to represent and formalize the content of these artifacts and how to relate their content to support, in particular, system assurance. When designing multi-functional systems, key artifacts are system-level requirements, functional specifications, and architectures in terms of their subsystem specifications. Links and traces between these artifacts are introduced to relate their contents. Traceability has the goal to relate artifacts. It is required for instance in standards for functional system safety such as the ISO 26262. An approach to specifying semantic relationships is shown, such that the activity of creating and using (navigating through) these relationships can be supported with automation.     

Evolution of XML schemas and documents from stereotyped UML class models: A traceable approach

Context

UML and XML are two of the most commonly used languages in software engineering processes. One of the most critical of these processes is that of model evolution and maintenance. More specifically, when an XML schema is modified, the changes should be propagated to the corresponding XML documents, which must conform with the new, modified schema.

Objective

The goal of this paper is to provide an evolution framework by which the XML schema and documents are incrementally updated according to the changes in the conceptual model (expressed as a UML class model). In this framework, we include the transformation and evolution of UML profiles specified in UML class models because they are widely used to capture domain specific semantics.

Method

We have followed a metamodeling approach which allowed us to achieve a language independent framework, not tied to the specific case of UML-XML. Besides, our proposal considers a traceability setting as a key aspect of the transformation process which allows changes to be propagated from UML class models to both XML schemas and documents.

Results

As a general framework, we propose a Generic Evolution Architecture (GEA) for the model-driven engineering context. Within this architecture and for the particular case of the UML-to-XML setting, our contribution is a UML-to-XML framework that, to our knowledge, is the only approach that incorporates the following four characteristics. Firstly, the evolution tasks are carried out in a conceptual model. Secondly, our approach includes the transformation to XML of UML profiles. Thirdly, the proposal allows stereotyped UML class models to be evolved, propagating changes to XML schemas and documents in such a way that the different elements are kept in synch. Finally, we propose a traceability setting that enables evolution tasks to be performed seamlessly.

Conclusions

Generic frameworks such as that proposed in this paper help to reduce the work overload experienced by software engineers in keeping different software artifacts synchronized.     

XTraQue: traceability for product line systems

Product line engineering has been increasingly used to support the development and deployment of software systems that share a common set of features and are developed based on the reuse of core assets. The large number and heterogeneity of documents generated during the development of product line systems may cause difficulties to identify common and variable aspects among applications, and to reuse core assets that are available under the product line. In this paper, we present a traceability approach for product line systems. Traceability has been recognised as an important task in software system development. Traceability relations can improve the quality of the product being developed and reduce development time and cost. We present a rule-based approach to support automatic generation of traceability relations between feature-based object-oriented documents. We define a traceability reference model with nine different types of traceability relations for eight types of documents. The traceability rules used in our work are classified into two groups namely (a) direct rules, which support the creation of traceability relations that do not depend on the existence of other relations, and (b) indirect rules, which require the existence of previously generated relations. The documents are represented in XML and the rules are represented in an extension of XQuery. A prototype tool called XTraQue has been implemented. This tool, together with a mobile phone product line case study, has been used to demonstrate and evaluate our work in various experiments. The results of these experiments are encouraging and comparable with other approaches that support automatic generation of traceability relations. This work has been partially supported by Dhurakijpundit University, Thailand.     

Automated traceability analysis for UML model refinements

During iterative, UML-based software development, various UML diagrams, modeling the same system at different levels of abstraction are developed. These models must remain consistent when changes are performed. In this context, we refine the notion of impact analysis and distinguish horizontal impact analysis–that focuses on changes and impacts at one level of abstraction–from vertical impact analysis–that focuses on changes at one level of abstraction and their impacts on another level. Vertical impact analysis requires that some traceability links be established between model elements at the two levels of abstraction. We propose a traceability analysis approach for UML 2.0 class diagrams which is based on a careful formalization of changes to those models, refinements which are composed of those changes, and traceability links corresponding to refinements. We show how actual refinements and corresponding traceability links are formalized using the OCL. Tool support and a case study are also described.     

Event-based traceability for managing evolutionary change

Although the benefits of requirements traceability are widely recognized, the actual practice of maintaining a traceability scheme is not always entirely successful. The traceability infrastructure underlying a software system tends to erode over its lifetime, as time-pressured practitioners fail to consistently maintain links and update impacted artifacts each time a change occurs, even with the support of automated systems. This paper proposes a new method of traceability based upon event-notification and is applicable even in a heterogeneous and globally distributed development environment. Traceable artifacts are no longer tightly coupled but are linked through an event service, which creates an environment in which change is handled more efficiently, and artifacts and their related links are maintained in a restorable state. The method also supports enhanced project management for the process of updating and maintaining the system artifacts.     

A scoped approach to traceability management

Traceability is the ability to describe and follow the life of a software artifact and a means for modeling the relations between software artifacts in an explicit way. Traceability has been successfully applied in many software engineering communities and has recently been adopted to document the transition among requirements, architecture and implementation. We present an approach to customize traceability to the situation at hand. Instead of automating tracing, or representing all possible traces, we scope the traces to be maintained to the activities stakeholders must carry out. We define core traceability paths, consisting of essential traceability links required to support the activities. We illustrate the approach through two examples: product derivation in software product lines, and release planning in software process management. By using a running software product line example, we explain why the core traceability paths identified are needed when navigating from feature to structural models and from family to product level and backward between models used in software product derivation. A feasibility study in release planning carried out in an industrial setting further illustrates the use of core traceability paths during production and measures the increase in performance of the development processes supported by our approach. These examples show that our approach can be successfully used to support both product and process traceability in a pragmatic yet efficient way.     

Applying a smoothing filter to improve IR-based traceability recovery processes: An empirical investigation

ContextTraceability relations among software artifacts often tend to be missing, outdated, or lost. For this reason, various traceability recovery approaches—based on Information Retrieval (IR) techniques—have been proposed. The performances of such approaches are often influenced by “noise” contained in software artifacts (e.g., recurring words in document templates or other words that do not contribute to the retrieval itself).AimAs a complement and alternative to stop word removal approaches, this paper proposes the use of a smoothing filter to remove “noise” from the textual corpus of artifacts to be traced.MethodWe evaluate the effect of a smoothing filter in traceability recovery tasks involving different kinds of artifacts from five software projects, and applying three different IR methods, namely Vector Space Models, Latent Semantic Indexing, and Jensen–Shannon similarity model.ResultsOur study indicates that, with the exception of some specific kinds of artifacts (i.e., tracing test cases to source code) the proposed approach is able to significantly improve the performances of traceability recovery, and to remove “noise” that simple stop word filters cannot remove.ConclusionsThe obtained results not only help to develop traceability recovery approaches able to work in presence of noisy artifacts, but also suggest that smoothing filters can be used to improve performances of other software engineering approaches based on textual analysis.     

Reasoning about UML/OCL class diagrams using constraint logic programming and formula

Model Driven Engineering promotes the use of models as the main artifacts in software and system development. Verification and validation of models are key activities to ensure the quality of the system under development. This paper presents a framework to reason about the satisfiability of class models described using the Unified Modeling Language (UML). The proposed framework allows us to identify possible design flaws as early as possible in the software development cycle. More specifically, we focus on UML Class Diagrams annotated with Object Constraint Language (OCL) invariants, which are considered to be the main artifacts in Object-Oriented analysis and design for representing the static structure of a system. We use the Constraint Logic programming (CLP) paradigm to reason about UML Class Diagrams modeling foundations. In particular, we use Formula as a model-finding and design space exploration tool. We also present an experimental Eclipse plug-in, which implements our UML model to Formula translation proposal following a Model Driven Architecture (MDA) approach. The proposed framework can be used to reason, validate, and verify UML Class Diagram software designs by checking correctness properties and generating model instances using the model exploration tool Formula.     

基于UML的需求分析过程研究

为提高软件生产过程的质量,文章提出了一种基于UML的概念建模方法。概念建模的目的是用一种规约详细描述系统的功能，主要工作是寻找系统必需的类。该方法利用熟知的UML的标准符号和技术．介绍了以时序图作为分析工具，将高层次的软件需求分解成更详细规约的需求分析过程(RAP),并讨论了确认、验证和可跟踪性问题。     

Supporting task-oriented modeling using interactive UML views

The UML is a collection of 13 diagram notations to describe different views of a software system. The existing diagram types display model elements and their relations. Software engineering is becoming more and more model-centric, such that software engineers start using UML models for more tasks than just describing the system. Tasks such as analysis or prediction of system properties require additional information such as metrics of the UML model or from external sources, e.g. a version control system. In this paper we identify tasks of model-centric software engineering and information that is required to fulfill these tasks. We propose views to visualize the information to support fulfilling the tasks. This paper reports on a large-scale controlled experiment to validate the usefulness of the proposed views that are implemented in our MetricView Evolution tool. The results of the experiment with 100 participants are statistically significant and show that the correctness of comprehension is improved by 4.5% and that the time needed is reduced by 20%.     

Towards a Subject-Oriented Model-Driven Framework

Model-Driven Architecture is an approach which tackles such problems as: the high availability that a software product requires to be ready for use, the high degree of evolution that a software system has nowadays, etc. However, in the development of large complex systems, the benefits of that approach have been diminished due to the size and complexity of models that describe these kinds of systems. At this point Aspect-Oriented Software Development (AOSD) appears to improve the understanding, reusability and adaptation of the software artefacts. Its mechanism is based on modularization of crosscutting concerns in well-identified isolated entities called aspects. For this reason we propose to use together AOSD and MDA in the hope of reducing the shortcomings of the latter. Thus, aspects like security, replication, real-time constraints, etc., will be modelled by specialist modellers independently throughout the MDA framework. Our proposal exploits a tool for checking the consistency between different models (aspects) at the same level of abstraction; supporting the traceability of UML elements, requirements, and concerns; and controlling the impact of changes throughout the MDA framework.     

Cognitive support,UML adherence,and XMI interchange in Argo/UML

Software design is a cognitively challenging task. Most software design tools provide support for editing, viewing, storing, and transforming designs, but lack support for the essential and difficult cognitive tasks facing designers. These cognitive tasks include decision-making, decision ordering, and task-specific design understanding.This paper describes Argo/UML, an object-oriented design tool using the unified modeling language (UML) design notation. Argo/UML supports several identified cognitive needs of software designers. This support is provided in the form of design tool features. We describe each feature in the context of Argo/UML and provide enough detail to enable other tool builders to provide similar support in their own tools. We also discuss our implementation of the UML and XMI standards, and our development approach.     

Estimating the number of remaining links in traceability recovery

Although very important in software engineering, establishing traceability links between software artifacts is extremely tedious, error-prone, and it requires significant effort. Even when approaches for automated traceability recovery exist, these provide the requirements analyst with a, usually very long, ranked list of candidate links that needs to be manually inspected. In this paper we introduce an approach called Estimation of the Number of Remaining Links (ENRL) which aims at estimating, via Machine Learning (ML) classifiers, the number of remaining positive links in a ranked list of candidate traceability links produced by a Natural Language Processing techniques-based recovery approach. We have evaluated the accuracy of the ENRL approach by considering several ML classifiers and NLP techniques on three datasets from industry and academia, and concerning traceability links among different kinds of software artifacts including requirements, use cases, design documents, source code, and test cases. Results from our study indicate that: (i) specific estimation models are able to provide accurate estimates of the number of remaining positive links; (ii) the estimation accuracy depends on the choice of the NLP technique, and (iii) univariate estimation models outperform multivariate ones.     

Semantics of trace relations in requirements models for consistency checking and inferencing

Requirements traceability is the ability to relate requirements back to stakeholders and forward to corresponding design artifacts, code, and test cases. Although considerable research has been devoted to relating requirements in both forward and backward directions, less attention has been paid to relating requirements with other requirements. Relations between requirements influence a number of activities during software development such as consistency checking and change management. In most approaches and tools, there is a lack of precise definition of requirements relations. In this respect, deficient results may be produced. In this paper, we aim at formal definitions of the relation types in order to enable reasoning about requirements relations. We give a requirements metamodel with commonly used relation types. The semantics of the relations is provided with a formalization in first-order logic. We use the formalization for consistency checking of relations and for inferring new relations. A tool has been built to support both reasoning activities. We illustrate our approach in an example which shows that the formal semantics of relation types enables new relations to be inferred and contradicting relations in requirements documents to be determined. The application of requirements reasoning based on formal semantics resolves many of the deficiencies observed in other approaches. Our tool supports better understanding of dependencies between requirements.     

DCTracVis: a system retrieving and visualizing traceability links between source code and documentation

It is well recognized that traceability links between software artifacts provide crucial support in comprehension, efficient development, and effective management of a software system. However, automated traceability systems to date have been faced with two major open research challenges: how to extract traceability links with both high precision and high recall, and how to efficiently visualize links for complex systems because of scalability and visual clutter issues. To overcome the two challenges, we designed and developed a traceability system, DCTracVis. This system employs an approach that combines three supporting techniques, regular expressions, key phrases, and clustering, with information retrieval (IR) models to improve the performance of automated traceability recovery between documents and source code. This combination approach takes advantage of the strengths of the three techniques to ameliorate limitations of IR models. Our experimental results show that our approach improves the performance of IR models, increases the precision of retrieved links, and recovers more correct links than IR alone. After having retrieved high-quality traceability links, DCTracVis then utilizes a new approach that combines treemap and hierarchical tree techniques to reduce visual clutter and to allow the visualization of the global structure of traces and a detailed overview of each trace, while still being highly scalable and interactive. Usability evaluation results show that our approach can effectively and efficiently help software developers comprehend, browse, and maintain large numbers of links.     

Means-ends and whole-part traceability analysis of safety requirements

Safety is a system property, hence the high-level safety requirements are incorporated into the implementation of system components. In this paper, we propose an optimized traceability analysis method which is based on the means-ends and whole-part concept of the approach for cognitive systems engineering to trace these safety requirements. A system consists of hardware, software, and humans according to a whole-part decomposition. The safety requirements of a system and its components are enforced or implemented through a means-ends lifecycle. To provide evidence of the safety of a system, the means-ends and whole-part traceability analysis method will optimize the creation of safety evidence from the safety requirements, safety analysis results, and other system artifacts produced through a lifecycle. These sources of safety evidence have a causal (cause-consequence) relationship between each other. The failure mode and effect analysis (FMEA), the hazard and operability analysis (HAZOP), and the fault tree analysis (FTA) techniques are generally used for safety analysis of systems and their components. These techniques cover the causal relations in a safety analysis. The causal relationships in the proposed method make it possible to trace the safety requirements through the safety analysis results and system artifacts. We present the proposed approach with an example, and described the usage of TRACE and NuSRS tools to apply the approach.