Automatically Detecting and Visualising Errors in UML Diagrams

UML has become the de facto standard for object-oriented modelling. Currently, UML comprises several different notations with no formal semantics attached to the individual diagrams or their integration, thus preventing rigorous analysis of the diagrams. Previously, we developed a formalisation framework that attaches formal semantics to a subset of UML diagrams used to model embedded systems. This paper describes automated structural and behavioural analyses applicable to UML diagrams using our formalisation framework. In addition to intra- and inter-diagram consistency checks, we discuss how simulation and model checking can be used in tandem for behavioural analysis of the UML diagrams. Our tools also visually interpret the analysis results in terms of the original UML diagrams, thereby facilitating their correction and refinement. We illustrate these capabilities through the modelling and analysis of UML diagrams for an automotive industrial case study. Correspondence and offprint requests to: Dr B. Cheng, Software Engineering and Network Systems Laboratory, Department of Computer Science and Engineering, Michigan State University, 3115 Engineering Building, East Lansing, MI 48824, USA. Tel.: +1 517 355 8344; Fax: +1 517 432 1061; Email: chengb@cse.msu.edu     

Rule-based update transformations and their application to model refactorings

A rule-based update transformation is a model transformation where a single model is transformed in place. A model refactoring is a model transformation that improves the design described in the model. A refactoring should only affect a previously chosen subset of the original model. In this paper, we discuss how to define and execute model refactorings as rule-based transformations in the context of the UML and MOF standards. We also present an experimental tool to execute this kind of transformation.     

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.     

Level of detail in UML models and its impact on model comprehension: A controlled experiment

Previous studies have shown that the style and rigor used in UML models vary widely across software projects [1], [2] and [3]. However, notwithstanding the varying use of styles and rigor, little research has been conducted to investigate the drivers and effects of using different styles and rigor in modeling on software development. In this paper, we evaluate Level of Detail (LoD) in UML models as a form of style and rigor in UML modeling. Using a UML model of a library system, we experimentally investigate the impact of LoD on model comprehension. More specifically, we explore whether LoD in UML models affects the correctness and efficiency in comprehending UML models. Using two independent groups of graduate students majoring in computer science, we performed a controlled experiment. The results of the experiment confirm the significant effect of LoD in UML models on model comprehension. Nevertheless, replication of this study is necessary, especially in contexts that involve professional software engineers, to improve the generalizability of the results.     

基于OWL本体的UML类图推理

分析UML模型一致性检测的研究意义,以及UML类图推理的研究现状,提出一种基于OWL本体的UML类图推理方案.研究UML类图向OWL本体转换的映射规则,给出UML类图包含关系、可满足性、等价关系和相离关系的判断方法及其推理规则.利用Jena推理机制实现了UML类图包含关系、可满足性、等价关系和相离关系的推理.     

一种顺序图的形式化描述与推理过程

以统一建模语言(UML,Unified Modeling Language)规范为基础,给出UML顺序图的形式化定义和语法描述,并进一步分析了对象消息发送和接收之间的一致性问题.最后,通过对实例推理过程的分析,对UML顺序图的特性作进一步的解释.这为基于UML顺序图的模型转换和模型验证提供了必要的前提条件,可用于对软件...     

Reusable model transformations

Model transformations written for an input metamodel may often apply to other metamodels that share similar concepts. For example, a transformation written to refactor Java models can be applicable to refactoring UML class diagrams as both languages share concepts such as classes, methods, attributes, and inheritance. Deriving motivation from this example, we present an approach to make model transformations reusable such that they function correctly across several similar metamodels. Our approach relies on these principal steps: (1) We analyze a transformation to obtain an effective subset of used concepts. We prune the input metamodel of the transformation to obtain an effective input metamodel containing the effective subset. The effective input metamodel represents the true input domain of transformation. (2) We adapt a target input metamodel by weaving it with aspects such as properties derived from the effective input metamodel. This adaptation makes the target metamodel a subtype of the effective input metamodel. The subtype property ensures that the transformation can process models conforming to the target input metamodel without any change in the transformation itself. We validate our approach by adapting well known refactoring transformations (Encapsulate Field, Move Method, and Pull Up Method) written for an in-house domain-specific modeling language (DSML) to three different industry standard metamodels (Java, MOF, and UML).     

Epsilon Flock: a model migration language

Model-driven engineering introduces additional challenges for controlling and managing software evolution. Today, tools exist for generating model editors and for managing models with transformation, validation, merging and weaving. There is limited support, however, for model migration—a development activity in which instance models are updated in response to metamodel evolution. In this paper, we propose conservative copy—a style of model transformation that we believe is well-suited to model migration—and Epsilon Flock—a compact model-to-model transformation language tailored for model migration. The proposed structures are evaluated by comparing the conciseness of model migration strategies written in different styles of transformation language, using several examples of evolution taken from UML and the graphical modelling framework.     

一种基于规则的模型转换方法*

尽管模型驱动开发(MDD)代表软件工程的发展方向,但是目前MDD还缺乏一套完整的转换规则描述方法和相应的实现机制,难以实现模型的自动转换。为此定义了一个平台独立模型到平台相关模型的转换框架,采用UML活动图说明模型转换的实现机制;基于OCL定义了转换规则的表示法,并结合UML模型到Java模型的转换给出了转换规则的定义。最后在一个具体的实例中验证了此方法的合理性和易用性。     

Modeling and enforcing invariants of dynamic software architectures

In this paper, we propose an “end-to-end” approach that supports dynamic reconfiguration of software architectures taking advantage of graphical modeling, formal methods and aspect-oriented programming. There are three ingredients of the proposal. The specification end of the solution is covered by a new UML profile enabling to specify the desired architectural style (model), its invariants and the intended reconfiguration operations. In order to verify the consistency of the model and the preservation of the invariants after every reconfiguration, we automatically generate formal specifications in Z notation from the defined model. At the runtime enforcing end of the solution, we propose to encode the enforcement logic as aspect in the AspectJ language. The third important ingredient that makes our approach end-to-end is the automatic translation of formal specifications into aspect-based enforcement code.     

Unified meta-modeling framework using bond graph grammars for conceptual modeling

Existing techniques for developing large scale complex engineering systems are predominantly software based and use Unified Modeling Language (UML). This leads to difficulties in model transformation, analysis, validation, verification and automatic code generation. Currently no general frameworks are available to bridge the concept-code gap rampant in design and development of complex, software-intensive mechatronic systems called cyber-physical systems. To fill this gap and provide an alternative approach to Object Management Group’s UML/SysML/OCL combination, we propose: Bond Graph based Unified Meta-Modeling Framework (BG-UMF). BG-UMF is a practical and viable alternative and uses a novel hybrid approach based on model unification and integration. The focus is on conceptual design and development of executable models for large systems. The viability of the framework is demonstrated through an application scenario: conceptual design and development of a navigation and control system for a rotor-craft UAV.     

A systematic review of UML model consistency management

Information System (IS) development has been beset by consistency problems since its infancy. These problems are greater still in UML software development, and are principally caused by the existence of multiple views (models) for the same system, and may involve potentially contradictory system specifications. Since a considerable amount of work takes place within the scope of model consistency management, this paper presents a systematic literature review (SLR) which was carried out to discover the various current model consistency conceptions, proposals, problems and solutions provided. To do this, a total of 907 papers related to UML model consistency published in literature and extracted from the most relevant scientific sources (IEEE Computer Society, ACM Digital Library, Google Scholar, ScienceDirect, and the SCOPUS Database) were considered, of which 42 papers were eventually analyzed. This systematic literature review resulted in the identification of the current state-of-the-art with regard to UML model consistency management research along with open issues, trends and future research within this scope. A formal approach for the handling of inconsistency problems which fulfils the identified limitations is also briefly presented.     

面向嵌入式软件开发的UML到Simulink模型转换方法

模型驱动开发及其关键技术模型转换是近年来软件工程领域研究的热点。在嵌入式软件开发早期,不仅需要对设计模型进行静态分析,更需要对其进行动态仿真,验证系统设计的正确性。如何把设计模型和仿真模型无缝连接起来是工业部门亟待解决的问题。深入调研了UML和Simulink模型转换研究现状,详细分析了模型驱动开发中模型转换的相关技术,提出了一种UML到Simulink的模型转换方法,设计了UML元模型、Simulink元模型,撰写了UML元模型到Simulink元模型的映射规则。最后选取自动驾驶仪系统的飞行控制软件作为案例,验证了该方法的正确性。该方法能实现UML和Simulink两种异构模型同构化,提高嵌入式软件开发效率,丰富并且完善模型驱动开发,也为飞行控制系统、高速铁路控制、机载航电系统等嵌入式软件开发提供了技术支持。     

Reconstructing a formal security model

Role-based access control (RBAC) is a flexible approach to access control, which has generated great interest in the security community. The principal motivation behind RBAC is to simplify the complexity of administrative tasks. Several formal models of RBAC have been introduced. However, there are a few works specifying RBAC in a way which system developers or software engineers can easily understand and adopt to develop role-based systems. And there still exists a demand to have a practical representation of well-known access control models for system developers who work on secure system development. In this paper we represent a well-known RBAC model with software engineering tools such as Unified Modeling Language (UML) and Object Constraints Language (OCL) to reduce a gap between security models and system developments. The UML is a general-purpose visual modeling language in which we can specify, visualize, and document the components of a software system. And OCL is part of the UML and has been used for object-oriented analysis and design as a de facto constraints specification language in software engineering arena. Our representation is based on a standard model for RBAC proposed by the National Institute of Standards and Technology. We specify this RBAC model with UML including three views: static view, functional view, and dynamic view. We also describe how OCL can specify RBAC constraints that is one of important aspects to constrain what components in RBAC are allowed to do. In addition, we briefly discuss future directions of this work.     

Maintaining constraints of UML models in distributed collaborative environments

Constraint maintenance plays an important role in keeping the integrity and validity of UML models in embedded software design. While constraint maintenance capabilities are reasonably adequate in existing UML modeling applications, little work has been done to address the distributed constraint maintenance issue in multi-user collaborative modeling environments. The nature of the issue is to maintain constraint consistently across distributed sites in a collaborative modeling environment in the face of concurrency. In this paper, we propose a novel solution to this issue, which can retain the effects of all concurrent modeling operations even though they may cause constraint violations. We further contribute a distributed constraint maintenance framework in which the solution is encapsulated as a generic engine that can be mounted in a variety of single-user UML modeling applications to support collaborative UML modeling and distributed constraint maintenance in embedded software design processes. This framework has been implemented in a prototype distributed collaborative UML modeling application CoRSA.     

一种模型转换分类方法及其在QVT中的应用

针对模型驱动的软件开发过程中潜在的交互性和一致性问题,介绍了一种模型转换分类的方法MTCM.根据模型和模型所描述的系统以及使用的建模语言的不同对模型转换进行细粒度的分类,然后按照此分类方法对OMG组织提出的模型转换标准QVT(查询/视图/转换)进行研究,并通过一个经典的模型转换实例即从UML模型到RDBMS模型的转换进行验证.分析得出结论,MTCM方法有助于提高模型转换的准确性和高效性.     

Definition and validation of model transformations

With model transformations becoming more widely used, there is an increasing need for approaches focussing on a systematic development of model transformations. Although a number of approaches for specifying model transformations exist, none of them focusses on systematically validating model transformations with respect to termination and confluence. Termination and confluence ensure that a model transformation always produces a unique result. Also called functionality, these properties are important requirements for practical applications of model transformations. In this paper, we introduce our approach to model transformation. Using and extending results from the theory of graph transformation, we investigate termination and confluence properties of model transformations specified in our approach. We establish a set of criteria for termination and confluence to be checked at design time by static analysis of the transformation rules and the underlying metamodels. Moreover, the criteria are formulated in such a way that they require less experience with the theory of graph transformation. Our concepts are illustrated by a running example of a model tranformation from statecharts to the process algebra Communicating Sequential Processes.     

Automated reasoning on UML conceptual schemas with derived information and queries

ContextIt is critical to ensure the quality of a software system in the initial stages of development, and several approaches have been proposed to ensure that a conceptual schema correctly describes the user’s requirements.ObjectiveThe main goal of this paper is to perform automated reasoning on UML schemas containing arbitrary constraints, derived roles, derived attributes and queries, all of which must be specified by OCL expressions.MethodThe UML/OCL schema is encoded in a first order logic formalisation, and an existing reasoning procedure is used to check whether the schema satisfies a set of desirable properties. Due to the undecidability of reasoning in highly expressive schemas, such as those considered here, we also provide a set of conditions that, if satisfied by the schema, ensure that all properties can be checked in a finite period of time.ResultsThis paper extends our previous work on reasoning on UML conceptual schemas with OCL constraints by considering derived attributes and roles that can participate in the definition of other constraints, queries and derivation rules. Queries formalised in OCL can also be validated to check their satisfiability and to detect possible equivalences between them. We also provide a set of conditions that ensure finite reasoning when they are satisfied by the schema under consideration.ConclusionThis approach improves upon previous work by allowing automated reasoning for more expressive UML/OCL conceptual schemas than those considered so far.     

A compositional semantics of UML-RSDS

This paper provides a semantics for the UML-RSDS (Reactive System Development Support) subset of UML, using the real-time action logic (RAL) formalism. We show how this semantics can be used to resolve some ambiguities and omissions in UML semantics, and to support reasoning about specifications using the B formal method and tools. We use ‘semantic profiles’ to provide precise semantics for different semantic variation points of UML. We also show how RAL can be used to give a semantics to notations for real-time specification in UML. Unlike other approaches to UML semantics, which concentrate on the class diagram notation, our semantic representation has behaviour as a central element, and can be used to define semantics for use cases, state machines and interactions, in addition to class diagrams.