Assessing the influence of import-coupling on OCL expression maintainability: A cognitive theory-based perspective

The aim of this paper is to present the definition of the measures for the import-coupling of OCL expressions, along with the empirical validation of these as early indicators of the maintainability of OCL expressions. This empirical validation has been carried out by means of an experiment and its replica, conducted with undergraduate students of Spanish and Argentinean universities, respectively. To perform this experimental activity, we have followed a cognitive theory-based approach, since the understanding of the cognitive demands that OCL expressions place on software engineers will allow us to examine in greater depth the real influence of import-coupling on the maintainability of OCL expressions. The empirical results, obtained through the analysis of the data from the experiment and its replica, first of all separately and then together after a meta-analysis study, reveal evidence suggesting that import-coupling exerts a certain amount of influence on the comprehensibility and modifiability of OCL expressions. The measures that have most influence on OCL expression comprehensibility are those related to problem objects (Number of Navigated Relationships (NNR), Weighted Number of Navigations (WNN), Depth of Navigations (DN) and Number of Attributes referred through Navigations (NAN)), relationships between problem objects (Number of Navigated Classes (NNC) and Number of Explicit Iterator variables (NEI)), as well as reified objects (Weighted Number of Collections Operations (WNCO)). On the other hand, it is only measures related to relationships between problem objects that are the main influence on OCL expression modifiability. The influence of import-coupling on the comprehensibility and modifiability of OCL expressions was reaffirmed through the cognitive complexity (i.e. we show that import-coupling affects the cognitive complexity and that the latter influences the comprehension and modification of OCL expressions). These results may have educational implications, apart from what they might mean for practitioners in the industry, as is explained in the conclusions.     

基于UML OCL、支持团队开发的企业组织元模型

组织模型不仅要支持传统的纵向的组织结构,而且还要支持以团队方式工作的横向组织结构。本文提出了包含组织纵向和横向结构的组织元模型,并采用UML对象约束语言(OCL)描述了元模型中实体与实体之间的联系和约束关系。除用OCL描述组织结构外,还显式地给出了组织规则的OCL表示方法。这样,便可将组织规则与组织结构相分离,从而在组织结构不变的情况下,通过修改组织规则,以达到提供企业敏捷性的目的。     

继电保护的UML建模及其转换

A lloy是一种具有简洁语法结构的形式语言(form al language),它能够对众多不同类型的系统建模、规范并进行自动化分析。而作为半形式语言(sem i-form al language)的UML(Un ified Modelling Language),是一种用于对软件系统进行描述、可视化和构架,并用于商业建模的语言。它作为一种对基于对象的系统进行建模、规范和执行的事实上的标准,已经被软件工程界所广泛接受。利用这两种语言各自的优势,提出了设计继电保护离散动作行为的UML模型的思想,并以三段式电流保护为例进行分析与建模,最后对其转化为A lloy模型以及对转化后的模型实施各种分析进行了论述。     

一种平衡Use Case需求模型复杂性的方法及应用

UML的Use Case模型由Use Case图和OCL描述两部分构成。设计者可在模型中使用较大的用例和较少的用例间的联系．形成较简单的用例图和较复杂的OCL描述，也可使用较复杂的用例图和较简单的OCL描述。介绍一种在用例图复杂性和OCL描述文档复杂性之间平衡的方法．需要时，可对用例图进行分解和规约，而不改变原模型的性质；同时介绍方法的一种应用．该应用也可作为独立的方法为建模提供帮助。     

带OCL的活动图多态性测试用例生成方法

研究UML活动图多态性测试用例的生成方法。形式化定义活动图,结合由类图、OCL约束和Liskov替换原则确定的多态性方法类集,扩展活动图中含多态信息的节点,得到多态扩展活动图。利用测试路径构造方法和覆盖准则,对多态扩展活动图进行遍历,生成测试用例。实验结果表明,该方法能生成含多态性信息的测试用例,提高测试覆盖度。     

An approach to test-driven development of conceptual schemas

Test-Driven Development (TDD) is an extreme programming development method in which a software system is developed in short iterations. In this paper we present the Test-Driven Conceptual Modeling (TDCM) method, which is an application of TDD for conceptual modeling, and we show how to develop a conceptual schema using it. In TDCM, a system's conceptual schema is incrementally obtained by performing three kinds of tasks: (1) Write a test the system should pass; (2) Change the schema to pass the test; and (3) Refactor the schema to improve its qualities. We also describe an integration approach of TDCM into a broad set of software development methodologies, including the Unified Process development methodology, the MDD-based approaches, the storytest-driven agile methods and the goal and scenario-oriented requirements engineering methods. We deal with schemas written in UML/OCL, but the TDCM method could be adapted to the development of schemas in other languages.     

Verification and validation of declarative model-to-model transformations through invariants

In this paper we propose a method to derive OCL invariants from declarative model-to-model transformations in order to enable their verification and analysis. For this purpose we have defined a number of invariant-based verification properties which provide increasing degrees of confidence about transformation correctness, such as whether a rule (or the whole transformation) is satisfiable by some model, executable or total. We also provide some heuristics for generating meaningful scenarios that can be used to semi-automatically validate the transformations.As a proof of concept, the method is instantiated for two prominent model-to-model transformation languages: Triple Graph Grammars and QVT.     

From UML/OCL to SBVR specifications: A challenging transformation

UML is currently the most widely used modeling language for the specification of the conceptual schema (CS) of an information system (IS). However, UML falls short when it comes to allow business people to define in their own language (e.g. using their own terms in natural language) the policies and rules by which they run their business. To this purpose, the semantics of business vocabulary and business rules (SBVR) metamodel specification was proposed. SBVR is conceptualized optimally for business people and it is designed to be used for business purposes, independently of information systems designs.     

一种基于FCA的本体优化算法

在本体学习过程中,随着本体中概念的增多,必然存在概念及概念间关系的冗余,如果不及时对本体进行优化,本体中的关键信息就会淹没于冗余的概念关系之间。针对这种情况,基于FCA(形式概念分析)理论提出一种本体优化算法。应用FCA中概念格相关知识建立本体原型,通过消除本体原型层次关系中的冗余,达到优化的目的。实验结果表明,本体原型经过优化,消除了层次关系中的冗余,使概念间的关系更加清晰,核心内容更加突出。     

PIM到关系PSM的转换方法研究

针对模型驱动体系结构中的模型转换问题,提出一种从PIM关系类图到SQL关系PSM的二步转换法,通过依赖、泛化、关联 3类关系的初步转换,使其脱离关系线,得到仅与属性类型相关的PIM类图,并对不同类型的属性制定相应的转换规则,利用一个具体示例展示了转换过程及其结果。实验结果表明,与简单的关联关系转换相比,该方法更全面,能够完整实现模型转换。