UML顺序图的形式化描述

1 引言统一建模语言UML(Unified Modeling Language)是标准的对象建模语言,它通过定义的多种图和模型元素描述系统分析和设计的结果,主要针对大型、复杂系统的建模。然而,UML却是半形式化的——其语法结构采用了形式化的规约,但其语义部分则是用自然语言描述的。由于复杂系统的建模往往需要进行严格的语义分析,而UML却缺乏准确的语义,这使得对模型难以进行一致性检查和正确性分析,进而限制了它的有效性。     

UML顺序图形式化语义的研究综述

为UML顺序图构建形式化语义,不仅有利于精确描述软件系统的动态交互过程,而且有利于进行基于UML模型的分析和验证,是有效提高软件系统可靠性的重要保障。结合近年来国内外对UML顺序图形式化语义的研究工作,分类阐述了各种方法,综合分析和比较了不同方法的工作机制和优缺点,指出了定义UML顺序图语义时需重点关注的问题。最后,对未来的研究工作与研究思路进行了梳理与展望。     

UML实时活动图的形式化分析

统一建模语言(UML)自从成为OMG规范后,应用越来越广泛．但UML没有精确的、形式化的语义阻碍了它的进一步发展．该文基于Petri网,给出带时间约束的UML活动图的形式化描述．与Petri网不同的是,Petri网的时间约束是在跃迁(transition)上,而作者将UML活动图的时间约束放在活动状态上,在此基础上,用整型时间的验证技术对实时活动图的时间性质加以分析,为实时系统的建模打下了基础.     

顺序图至Petri网转化方法的研究与实现

作为一种面向对象分析和设计建模语言，统一建模语言（UML）已经越来越多的被用在大型系统中，然而，UML是半形式化的，这使得很难对其进行严格的语义分析和正确性验证。顺序图作为UML动态描述机制的重要组成部分，同样存在这样的问题，而Petri网作为一种建模工具，有着严格的形式化语义，而且有很多成熟的分析方法。该文针对UML20顺序图模型，结合几个简单Petri网结构，提出了将顺序图转换为Petri网的算法，最后通过实例说明了转化算法的有效性。     

UML顺序图中消息的形式化描述与相关特性分析

为了实现基于UML顺序图的自动化测试,研究了顺序图中消息的形式化描述方法.形式化地定义了消息的发送和接收,并对二者的一致性关系进行了分析.提出了活动点的概念,讨论了其所具有的性质.建立了活动点集合上的二元关系描述方法,形式化地讨论了单个对象活动点集合与顺序图中全部活动点集合中该二元关系的具体表现.定义了消息集合上的二元关系,分析了其所具有的性质.最后,对顺序图中的时间约束特性和消息约束特性进行了形式化的分析.     

基于时序描述逻辑的UML顺序图形式化方法

根据统一建模语言(UML)顺霤图的时霤特征,提出一种基于时霤描述逻辑ALCQIUS的UML顺霤图需式化方法。研究ALCQIUS时霤扩展部分的语法和语义、ALCQIUS断言公式集一致霆定理,给出ALCQIUS断言公式集一致霆推理算法,并证明该推理算法的可判定霆。以公安报警系统为例,说明基于ALCQIUS的UML顺霤图需式化规约和需式化验证具备可霂霆,并且ALCQIUS为UML顺霤图需式化提供了合理的逻辑基础。     

UML顺序图的结构化操作语义研究

UML顺序图侧重于展示对象之间的消息交互过程,但其动态语义缺乏形式化的描述,不利于对顺序图模型的准确理解和基于该模型的测试用例生成。为此,依据UML1. 5规范,采用BN定义顺序图的形式化语法,提出了活动点的概念;在此基础上,讨论并给出了单个对象执行消息动作的结构化操作语义以及顺序图模型的整体结构化操作语义,为模型检验和基于顺序图的测试用例生成提供了前提。     

从UML顺序图生成状态图的一个方法

UML (Unified Modeling Language) is a visual modeling language used for specifying,visualizing,constructing,and documenting the artifacts of software systems by various diagrams.It has been widely accepted as a standard modeling language in both academic and industrial areas.UML sequence diagrams are mostly used in specifying system requirements.By representing interactions,which are arranged in time sequence,between the objects in a system,sequence diagrams can construct scenarios indicating the system‘‘s functions.A UML statechart diagram is a graph shows the sequences of states that an object or an interaction goes through during its life in response to received stimuli,together with its responses and actions.It‘‘s useful in the design stage of system development.This essay discusses the computer-aided transformation from sequence diagrams to statechart diagrams,which can offer strong support for the transfering from requirement analysis to system design in the software development process.With OCL (Object Control Language) semantic constrain,a transform algorithm is provided in the paper.And the differences with the related works are also mentioned.     

UML活动图到Petri网的转换方法及实现研究

统一建模语言UML缺乏形式化语义,由其描述的模型难以进行动态的分析和验证。而Petri网在具有丰富而严格语义的同时,又有严谨的数学分析方法。综合运用Petri网和UML能够提高软件描述的全面性、一致性、精确性和完整性。研究了UML活动图向Petri网的转换规则,并依据转换规则实现了模型转换工具APConverter。此工具能有效地将活动图转换为Petri网模型并生成PNML文件,进而更好地对UML模型进行分析和验证。     

基于时序描述逻辑的UML顺序图形式化研究

在统一建模语言（UML）规范中顺序图的语义是以自然语言的形式描述的,是一种半形式化的语言,不能对系统的交互行为进行形式化分析及论证.针对UML顺序图缺乏精确的形式化描述问题,根据顺序图的时序特征,提出了增加交互操作符的UML顺序图的六元组形式化方法.对描述逻辑进行时序扩展,得到可表示动态和时序语义的形式化规范——时序描述逻辑.应用时序描述逻辑的时态算子得到时序描述逻辑语义形式的UML顺序图.用UML顺序图描述完整的C语言执行过程,将其形式化描述,实验结果表明,这种方法是可行的.     

由序列图合成状态图

序列图和状态图对于描述和理解面向对象软件系统有着极其重要的作用。符合UML标准的序列图和状态图存在信息重叠,根据序列图提供的信息可以合成状态图。给出了在Rational Rose中由序列图合成状态图工具的实现。     

Assert and negate revisited: Modal semantics for UML sequence diagrams

Live Sequence Charts (LSC) extend Message Sequence Charts (MSC), mainly by distinguishing possible from necessary behavior. They thus enable the specification of rich multi-modal scenario-based properties, such as mandatory, possible and forbidden scenarios. The sequence diagrams of UML 2.0 enrich those of previous versions of UML by two new operators, assert and negate, for specifying required and forbidden behaviors, which appear to have been inspired by LSC. The UML 2.0 semantics of sequence diagrams, however, being based on pairs of valid and invalid sets of traces, is inadequate, and prevents the new operators from being used effectively. We propose an extension of, and a different semantics for this UML language—Modal Sequence Diagrams (MSD)—based on the universal/existential modal semantics of LSC. In particular, in MSD assert and negate are really modalities, not operators. We define MSD as a UML 2.0 profile, thus paving the way to apply formal verification, synthesis, and scenario-based execution techniques from LSC to the mainstream UML standard. Preliminary version appeared in SCESM '06: Proc. of the 2006 Int. workshop on Scenarios and State Machines, Shanghai, China (May 2006) [15]. This research was supported by the Israel Science Foundation (grant No.287/02-1), and by The John von Neumann Minerva Center for the Development of Reactive Systems at the Weizmann Institute of Science.     

Simulation-based analysis of UML statechart diagrams: methods and case studies

We present a comprehensive unified modeling language (UML) statechart diagram analysis framework. This framework allows one to progressively perform different analysis operations to analyze UML statechart diagrams at different levels of model complexity. The analysis operations supported by the framework are based on analyzing Petri net models converted from UML statechart diagrams using a previously proposed transformation approach. After introducing the general framework, the paper emphasizes two simulation-based analysis operations from the framework: direct MSC inspection, which provides a visual representation of system behavior described by statechart diagrams; and a pattern-based trace query technique, which can be used to define and query system properties. Two case-study examples are presented with different emphasis. The gas station example is a simple multi-object system used to demonstrate both the visual and query-based analysis operations. The early warning system example uses only one object, but features composite states and includes analysis specifically aimed at one composite state feature, history states.

Assessing the influence of stereotypes on the comprehension of UML sequence diagrams: A family of experiments

Context

The conventional wisdom states that stereotypes are used to clarify or extend the meaning of model elements and consequently should be helpful in comprehending the diagram semantics.

Objective

The main goal of this work is to present a family of experiments that we have carried out to investigate whether the use of stereotypes improves the comprehension of UML sequence diagrams.

Method

The family of experiments consists of an experiment and two replications carried out with 78, 29 and 36 undergraduate Computer Science students, respectively. The comprehension of UML sequence diagrams with and without stereotypes was analyzed from three different perspectives borrowed from the Cognitive Theory of Multimedia Learning (CTML): semantic comprehension, retention and transfer. In addition, we carried out a meta-analysis study to integrate the different data samples.

Results

The statistical analysis and meta-analysis of the data obtained from each experiment separately indicates that the use of the proposed stereotypes helps improving the comprehension of the diagrams, especially when the subjects are not familiar with the domain.

Conclusions

The set of stereotypes presented in this work seem to be helpful for a better comprehension of UML sequence diagrams, especially with not well-known domains. Although further research is necessary for strengthening these results, introducing these stereotypes both in academia and industry could be an interesting practice for checking the validity of the results.     

基于Time Petri Nets的UML时序图分析

引入一种称为Clock的变迁,用来改进TPNs,讨论了如何将时序图转换为基于Clock变迁的TPNs,使这种TPNs能正确反映时序图的流程和时间约束。最后,利用普通Petri网的可达性分析技术对时序图模型进行了分析和验证。     

基于UML协作图的集成测试序列生成方法

随着软件测试自动化的要求,以及UML在面向对象软件开发领域中的广泛应用,基于UML的面向对象软件测试正日益受到关注。集成测试是面向对象软件测试的一个重要阶段,在基于UML协作图生成面向对象软件的集成测试用例的过程中,一个重要内容是测试序列的生成。针对集成测试序列数量容易膨胀的现象,根据UML协作图的特点,应用过程间受限控制流图(IR-CFG)描述协作图的消息间逻辑控制关系。给出了由RationalRose开发的规格说明文件生成IRCFG的算法,并介绍了IRCFG的几种覆盖准则与基于IRCFG生成测试序列的方法。     

基于时序逻辑的UML2.0通信图语义研究

UML2.0通信图可以表示对象之间的交互,很适合用于对系统的交互行为建模,但由于UML缺乏精确语义,使得难以对其所表示的系统行为进行分析和验证.XYZ/E是可执行线性时序逻辑语言,既可描述系统的静态语义和动态语义.在定K.UML2.0通信图的形式化语法的基础上,给出了通信图的XYZ/E时序逻辑语义,为进一步的系统分析和验证提供了形式化基础.     

Ambiguity and structural properties of basic sequence diagrams

Sequence Diagrams (SDs) are one of the most popular elements of the UML notation to model the dynamics of systems. However, the graphical representation of basic SDs suffers from an inherent ambiguity that has led to different definitions in UML 1.x and in UML 2.0. This ambiguity paves the way for the consideration of several semantics for basic SDs. The paper studies four of these semantics and shows to what extent their differences for a given SD (that is the amount of ambiguity of this diagram) comes from its structural properties (linearity, local control and local causality). The fulfilment of these properties can serve as a measure of the ambiguity of a SD, and thus the attention to be paid at its validation.     

Guidelines on the aesthetic quality of UML class diagrams

In the past, formatting guidelines have proved to be a successful method to improve the readability of source code. With the increasing success of visual specification languages such as UML for model-driven software engineering visual guidelines are needed to standardize the presentation and the exchange of modeling diagrams with respect to human communication, understandability and readability. In this article, we introduce a new and encompassing taxonomy of visual guidelines capturing the aesthetic quality of UML class diagrams. We propose these guidelines as a framework to improve the aesthetic quality and thus the understandability of UML class diagrams. To validate this claim, we describe in detail a controlled experiment carried out as a pilot study to gather preliminary insights on the effects of some of the guideline rules on the understandability of UML class diagrams.     

扩展UML在语义Web建模中的应用研究

随着语义Web的研究与发展,语义Web的建模很可能成为主要的瓶颈。近年来,作为概念建模语言的UML为语义Web建模,已经成为一个重要的研究主题。简要分析了统一建模语言（UML）和本体论Web语言（OWL）的目标、原理和语义,对相似部分采用了直接的映射,对于不兼容部分,通过扩展UML,达到对OWL建模的目的。