对象约束语言对武器系统效能评估指标体系的描述与验证

武器系统效能评估是武器系统设计过程中的重要环节,效能评估指标体系作为效能评估的前提和基础,其描述的精确性将直接影响武器系统效能评估的结果.针对武器系统的设计过程,提出了一种效能评估指标体系的描述方法,即元模型描述方法;引入统一建模语言(UML)规范的一部分对象约束语言(OCL)对其进行精确描述.最后,通过实验验证了OCL描述的正确性,为武器系统设计过程中的效能评估提供依据.     

基于对象约束语言规格的变异分析

由于传统形式化语言的复杂性以及当前变异分析系统性能问题,基于规格的变异分析一直没有得到广泛的应用.介绍辅助UML建模的对象约束语言(OCL)和基于规格变异分析的基本理论.提出一种新型的OCL规格变异系统的设计方案,并详细描述了一些变异算子的具体实现.解决了传统变异系统的性能缺陷,提高了变异分析的实用性.     

功率放大器两种实现方法的比较

功率放大电路通常由集成功率放大器件或分立元件放大电路组成，两者各有优缺点，就如何正确地利用两种不同电路原理，调试，性能，结果加以分析比较。     

MDA模型转换的OCL扩展

模型驱动架构(MDA)是继CORBA,UML之后由OMG推出的重要的软件开发方法学.MDA的核心是模型转换,模型转换语言又是实施模型转换的关键.本文从MOF元模型的角度首先对OCL进行动态特性的扩展,使其具备表达动态行为语义的能力;然后通过扩展相关关键字,定义了一个完整的模型转换程序框架;并提出创建中间转换对象实现了模型转换的可追溯性以及源模型和目标模型转换的同步性.     

基于EMF和OCL的MDA软件工程方法研究

随着基于模型的软件工程方法的兴起，模型逐渐地变为软件工程中的重要元素，介绍了OMG规范MOF、XMI和OCL及在Eclipse软件工程环境下的相关实现EMF，说明了统一建模语言UML的使用方式和存在的问题，介绍了如何用EMF和OCL来设计建模语言，比较了基于EMF的建模语言和基于EBNF的计算机语言之间的区别与联系，给出了结合模板和OCL的模型转换方法，通过把UML类模型转换到O／R映射框架说明了此方法的有效性，分析了MDA软件工程方法的重用机制。     

基于AOP技术的软件性质监控框架

针对软件运行时可信保障存在的相关问题,提出了基于AOP技术的软件性质监控框架。本框架使用OCL(Object Constraint Language)和UML Profile的SPT(Schedulability,Performance and Time)规范实现了软件性质在模型上的描述,基于描述并独立于被监控软件自动生成监控方面,将监控方面编织入被监控软件,从而使被监控软件具有运行时软件性质监控能力。     

Performance comparison of query-based techniques for anti-pattern detection

ContextProgram queries play an important role in several software evolution tasks like program comprehension, impact analysis, or the automated identification of anti-patterns for complex refactoring operations. A central artifact of these tasks is the reverse engineered program model built up from the source code (usually an Abstract Semantic Graph, ASG), which is traditionally post-processed by dedicated, hand-coded queries.ObjectiveOur paper investigates the costs and benefits of using the popular industrial Eclipse Modeling Framework (EMF) as an underlying representation of program models processed by four different general-purpose model query techniques based on native Java code, OCL evaluation and (incremental) graph pattern matching.MethodWe provide in-depth comparison of these techniques on the source code of 28 Java projects using anti-pattern queries taken from refactoring operations in different usage profiles.ResultsOur results show that general purpose model queries can outperform hand-coded queries by 2–3 orders of magnitude, with the trade-off of an increased in memory consumption and model load time of up to an order of magnitude.ConclusionThe measurement results of usage profiles can be used as guidelines for selecting the appropriate query technologies in concrete scenarios.     

On OCL-based imperative languages

The Object Constraint Language (OCL) is a well-accepted ingredient in model-driven engineering and accompanying modeling languages such as UML (Unified Modeling Language) and EMF (Eclipse Modeling Framework) that support object-oriented software development. Among various possibilities, OCL offers the formulation of class invariants and operation contracts in form of pre- and postconditions, and side-effect free query operations. Much research has been done on OCL and various mature implementations are available for it. OCL is also used as the foundation for several modeling-specific programming and transformation languages. However, an intrusive way of embedding OCL into these language hampers us when we want to benefit from the existing achievements for OCL. In response to this shortcoming, we propose the language SOIL (Simple OCL-like Imperative Language), which we implemented in the UML and OCL modeling tool USE to amend its declarative model validation features. The expression sub-language of SOIL is identical to OCL. SOIL adds imperative constructs for programming in the domain of models. Thus by employing OCL and SOIL, it is possible to describe any operation in a declarative way and in an operational way on the modeling level without going into the details of a conventional programming language. In contrast to other similar approaches, the embedding of OCL into SOIL is done in a careful, non-intrusive way so that purity of OCL is preserved.     

基于角色访问控制模型约束的OCL描述

基于角色的访问控制模型(RBAC)凭借其灵活的授权机制、强大的管理功能和完善的安全策略越来越引起人们的研究兴趣,随着研究的不断深入,面向对象的研究方法也逐渐应用到这个模型中,促进了它的迅速发展。UML作为一种强大的建模语言,不只是局限于支持面向对象的分析与设计,还支持从需求分析开始的软件开发的全过程,通过UML的描述可以使理论模型更加直观地应用到实际系统开发。该文使用UML的对象约束语言(OCL)来描述RBAC中的相关约束,使约束描述更加标准化,更有利于系统开发人员对模型的理解和促进RBAC模型的系统开发。     

形式化语言B与UML/OCL的比较

该文介绍了形式化方法中B语言和UML/OCL语言,从软件开发生命周期的角度对B语言和OCL语言进行了比较,归纳了这两种形式化语言的异同和各自的适用范围。