A multi-level approach to modeling language extension in the Enterprise Systems Domain

As the number and diversity of technologies involved in building enterprise systems continues to grow so does the importance of modeling tools that are able to present customized views of enterprise systems to different stakeholders according to their needs and skills. Moreover, since the range of required view types is continuously evolving, it must be possible to extend and enhance the languages and services offered by such tools on an ongoing basis. However, this can be difficult with today׳s modeling tools because the meta-models that define the languages, views and services they support are usually hardwired and thus not amenable to extensions. In practice, therefore, various workarounds have to be used to extend a tool׳s underlying meta-model. Some of these are built into the implemented modeling standards (e.g. UML 2, BPMN 2.0 and ArchiMate 2.0) while others have to be applied by complementary, external tools (e.g. annotation models). These techniques not only increase accidental complexity, they also reduce the ability of the modeling tool to ensure adherence to enterprise rules and constraints. In this paper we discuss the strengths and weaknesses of the various approaches for language extension and propose a modeling framework best able to support the main extension scenarios currently found in practice today.     

Assessing the quality of metamodels

The complexity and diversity of modern software demands a variety of metamodel-based modeling languages for software development. Existing languages change continuously, and new ones are constantly emerging. In this situation, and especially for metamodel-based modeling languages, a quality assurance mechanism for metamodels is needed. This paper presents an approach to assessing the quality of metamodels. A quality model, which systematically characterizes and classifies quality attributes, and an operable measuring mechanism for effectively assessing the quality of metamodels based on the quality model, are presented, using UML as the main example.     

BPMNt: A BPMN extension for specifying software process tailoring

ContextAlthough SPEM 2.0 has great potential for software process modeling, it does not provide concepts or formalisms for precise modeling of process behavior. Indeed, SPEM fails to address process simulation, execution, monitoring and analysis, which are important activities in process management. On the other hand, BPMN 2.0 is a widely used notation to model business processes that has associated tools and techniques to facilitate the aforementioned process management activities. Using BPMN to model software development processes can leverage BPMN’s infrastructure to improve the quality of these processes. However, BPMN lacks an important feature to model software processes: a mechanism to represent process tailoring.ObjectiveThis paper proposes BPMNt, a conservative extension to BPMN that aims at creating a tailoring representation mechanism similar to the one found in SPEM 2.0.MethodWe have used the BPMN 2.0 extensibility mechanism to include the representation of specific tailoring relationships namely suppression, local contribution, and local replacement, which establish links between process elements (such as in the case of SPEM). Moreover, this paper also presents some rules to ensure the consistency of BPMN models when using tailoring relationships.ResultsIn order to evaluate our proposal we have implemented a tool to support the BPMNt approach and have applied it for representing real process adaptations in the context of an academic management system development project. Results of this study showed that the approach and its support tool can successfully be used to adapt BPMN-based software processes in real scenarios.ConclusionWe have proposed an approach to enable reuse and adaptation of BPMN-based software process models as well as derivation traceability between models through tailoring relationships. We believe that bringing such capabilities into BPMN will open new perspectives to software process management.     

UML-CI: A reference model for profiling critical infrastructure systems

The study of critical infrastructure systems organization and behavior has drawn great attention in the recent years. This is in part due to their great influence on the ordinary life of every citizen. In this paper, we study critical infrastructures’ characteristics and propose a reference model based on the Unified Modeling Language (UML). This reference model attempts to provide suitable means for the task of modeling an infrastructure system through offering five major metamodels. We introduce each of these metamodels and explain how it is possible to integrate them into a unique representation to characterize various aspects of an infrastructure system. Based on the metamodels of UML-CI, infrastructure system knowledge bases can be built to aid the process of infrastructure system modeling, profiling, and management.     

基于UML的软件体系结构的定量评估

软件体系结构是软件开发过程的关键制品,应该尽早地分析和评估其质量.目前研究的软件体系结构评估主要集中在基于场景的评估方法,其特点是定性的、主观的、无需专用的体系结构描述语言.本文提出以统一建模语言UML作为软件体系结构描述语言以及度量的软件体系结构的定量评估.针对UML的可视化、多视图、半形式化以及一致地应用在整个软件开发活动的特性,提出一组UML度量,从UML图所表达的信息含量、可视化影响以及图形建模元素之间的关联性这三个方面度量软件体系结构.分析并讨论这组UML度量在评估软件体系结构的规模、复杂性和结构性等质量属性方面的应用.     

The many meanings of UML 2 Sequence Diagrams: a survey

Scenario languages are widely used in software development. Typical usage scenarios, forbidden behaviors, test cases, and many more aspects can be depicted with graphical scenarios. Scenario languages were introduced into the Unified Modeling Language (UML) under the name of Sequence Diagrams. The 2.0 version of UML changed Sequence Diagrams significantly and the expressiveness of the language was highly increased. However, the complexity of the language (and the diversity of the goals Sequence Diagrams are used for) yields several possible choices in its semantics. This paper collects and categorizes the semantic choices in the language, surveys the formal semantics proposed for Sequence Diagrams, and presents how these approaches handle the various semantic choices.     

A generic framework for modeling heterogeneous real-time systems

Complex real-time systems usually consist of heterogeneous components. These components interact with different semantics. Modeling these systems normally need integrating several domain-specific tools such as UML, Simulink. But interchanging data between these tools is very difficult. UML is a standard modeling language for object-oriented software development, used more and more in real-time domain. It provides several extensibility mechanisms to allow modeling special domains. This paper presents a generic framework, which is based on UML notations and metamodels, for heterogeneous modeling real-time systems. So engineers from different domains can work together on a unified platform.     

Engineering Web-Based Systems with UML Assets

Software development is a product of evolution. It builds on the experiences of the individual and the community, continually refining every aspect of process. Web centric architectures are no different. Their ever-increasing levels of functionality and complexity are evident in the latest generations of web applications. In this paper we discuss some standards that enable teams to build, communicate and apply their experiences in the art of web application software development. These standards appropriate various levels of abstraction, and bring the focus of web application development back to the team. Combining UML representation of web-based systems with techniques for packaging these solutions for reuse can positively impact development timelines and efficiencies.     

Assessing the understandability of UML statechart diagrams with composite states—A family of empirical studies

The main goal of this work is to present a family of empirical studies that we have carried out to investigate whether the use of composite states may improve the understandability of UML statechart diagrams derived from class diagrams. Our hypotheses derive from conventional wisdom, which says that hierarchical modeling mechanisms are helpful in mastering the complexity of a software system. In our research, we have carried out three empirical studies, consisting of five experiments in total. The studies differed somewhat as regards the size of the UML statechart models, though their size and the complexity of the models were chosen so that they could be analyzed by the subjects within a limited time period. The studies also differed with respect to the type of subjects (students vs. professionals), the familiarity of the subjects with the domains of the diagrams, and other factors. To integrate the results obtained from each of the five experiments, we performed a meta-analysis study which allowed us to take into account the differences between studies and to obtain the overall effect that the use of composite states has on the understandability of UML statechart diagrams throughout all the experiments. The results obtained are not completely conclusive. They cast doubts on the usefulness of composite states for a better understanding and memorizing of UML statechart diagrams. Composite states seem only to be helpful for acquiring knowledge from the diagrams. At any rate, it should be noted that these results are affected by the previous experience of the subjects on modeling, as well as by the size and complexity of the UML statechart diagrams we used, so care should be taken when generalizing our results.     

Complexity metrics for Workflow nets

Process modeling languages such as EPCs, BPMN, flow charts, UML activity diagrams, Petri nets, etc., are used to model business processes and to configure process-aware information systems. It is known that users have problems understanding these diagrams. In fact, even process engineers and system analysts have difficulties in grasping the dynamics implied by a process model. Recent empirical studies show that people make numerous errors when modeling complex business processes, e.g., about 20% of the EPCs in the SAP reference model have design flaws resulting in potential deadlocks, livelocks, etc. It seems obvious that the complexity of the model contributes to design errors and a lack of understanding. It is not easy to measure complexity, however. This paper presents three complexity metrics that have been implemented in the process analysis tool ProM. The metrics are defined for a subclass of Petri nets named Workflow nets, but the results can easily be applied to other languages. To demonstrate the applicability of these metrics, we have applied our approach and tool to 262 relatively complex Protos models made in the context of various student projects. This allows us to validate and compare the different metrics. It turns out that our new metric focusing on the structuredness outperforms existing metrics.     

The impact of structural complexity on the understandability of UML statechart diagrams

The effectiveness of current software development strategies, such as Model-Driven Development (MDD), depends largely on the quality of their primary artefacts, i.e. software models. As the standard modelling language for software systems is the Unified Modelling Language (UML), quality assurance of UML models is a major research field in Computer Science. Understandability, i.e. a model’s ability to be easily understood, is one model quality property that is currently heavily under investigation. In particular, researchers are searching for the factors that determine an UML model’s understandability and are looking for ways to manipulate these factors. This paper presents an empirical study investigating the effect that structural complexity has on the understandability of one particular type of UML model, i.e. the statechart diagram. Based on data collected in a family of three experiments, we have identified three dimensions of structural complexity that affect understandability: (i) the size and control flow complexity of the statechart in terms of features such as the number of states, events, guards and state transitions; (ii) the actions that are performed when entering or leaving a state; (iii) the sequence of actions that is performed while staying within a state. Based on these structural complexity dimensions we have built an understandability prediction model using a regression technique that is specifically recommended for data obtained through a repeated measures design. Our test results show that each of the underlying structural complexity dimensions has a significant impact on the understandability of a statechart diagram.     

BPMN 2.0过程模型的语义和分析

BPMN 2.0已成为了建模业务过程事实上的标准。BPMN 2.0过程模型中建模元素的混用会产生控制流方面的语义错误。首先,建立了BPMN 2.0过程模型到工作流网的映射,并使用Petri网来形式定义过程模型的语义;其次,借助Petri网的分析技术,使用这种定义的语义对BPMN 2.0过程模型进行了合理性分析。实验结果表明,这种形式化可以识别BPMN 2.0过程模型中的语义错误。     

A metamodel to integrate business processes time perspective in BPMN 2.0

ContextBusiness Process Management (BPM) is becoming a strategic advantage for organizations to streamline their operations. Most business experts are betting for OMG Business Process Model and Notation (BPMN) as de-facto standard (ISO/IEC 19510:2013) and selected technology to model processes. The temporal dimension underlies in any kind of process however, technicians need to shape this perspective that must also coexist with task control flow aspects, as well as resource and case perspectives. BPMN poorly gathers temporary rules. This is why there are contributions that extend the standard to cover such dimension. BPMN is mainly an imperative language. There are research contributions showing time constraints in BPMN, such as (i) BPMN patterns to express each rule with a combination of artifacts, thus these approaches increase the use of imperative BPMN style, and (ii) new decorators to capture time rules semantics giving clearer and simpler comprehensible specifications. Nevertheless, these extensions cannot yet be found in the present standard.ObjectiveTo define a time rule taxonomy easily found in most business processes and look for an approach that applies each rule with current BPMN 2.0 standard in a declarative way.MethodA model-driven approach is used to propose a BPMN metamodel extension to address time-perspective.ResultsWe look at a declarative approach where new time specifications may overlie the main control flow of a BPMN process. This proposal is totally supported with current BPMN standard, giving a BPMN metamodel extension with OCL constraints. We also use AQUA-WS as a software project case study which is planned and managed with MS Project. We illustrate business process extraction from project plans.ConclusionThis paper suggests to handle business temporal rules with current BPMN standard, along with other business perspectives like resources and cases. This approach can be applied to reverse engineering processes from legacy databases.     

Visual modeling for Web 2.0 applications using model driven architecture approach

Mashup is now a major Web 2.0 technology because, rather than simply aggregating Web content, it combines various Web resources from other websites. Considering Web 2.0 mashups from a software engineering perspective, a visual modeling approach is crucial. Current Web 2.0 developments, however, do not support a conceptual modelling for Web 2.0 applications. This leads to inefficient development processes and a low potential for reuse. The Unified Modeling Language (UML) is a general-purpose modeling language that may be used in widely varying application domains. However, UML often lacks elements for modeling and representing concrete concepts of specific domains such as Web 2.0 mashup modeling. To address these shortcomings, this study proposes Web2.0MUML, a Model Driven Architecture (MDA) approach and UML profile for modeling Web 2.0 mashups. The Web2.0MUML profile extends UML by using a profile mechanism for Web 2.0 mashup modeling that presents the relevant structural properties of Web 2.0 at the conceptual level.     

From UML/SPT models to schedulability analysis: approach and a prototype implementation using ATL

Model Driven Architecture (MDA) is a software development approach promoted by the OMG. MDA is based on two key concepts, models and model transformations. Several kinds of models are generally used throughout the development process to specify a software system and to support its analysis and validation. UML and its extensions, such as the UML profile for real-time systems (UML/SPT), are commonly used to define the structure and the behavior of software systems while other models, such as performance models or schedulability models, are more suitable for performance or schedulability analysis, respectively. In this paper we discuss a model transformation enabling the derivation of schedulability analysis models from UML/SPT models. As a proof of concepts, we present a prototype implementation of this model transformation using ATL. We provide a definition of the source and target metamodels using the metamodel specification language KM3 and we specify the transformation in an ATL module. We discuss the merits and limitations of our approach and of its implementation.     

DSMDiff: a differentiation tool for domain-specific models

Model differentiation techniques, which provide the capability to identify mappings and differences between models, are essential to many model development and management practices. There has been initial research toward model differentiation applied to Unified Modeling Language (UML) diagrams, but differentiation of domain-specific models has not been explored deeply in the modeling community. Traditional modeling practice using the UML relies on a single fixed general-purpose language (i.e., all UML diagrams conform to a single metamodel). In contrast, Domain-Specific Modeling (DSM) is an emerging model-driven paradigm in which multiple metamodels are used to define various modeling languages that represent the key concepts and abstractions for particular domains. Therefore, domain-specific models may conform to various metamodels, which requires model differentiation algorithms be metamodel-independent and able to apply to multiple domain-specific modeling languages. This paper presents metamodel-independent algorithms and associated tools for detecting mappings and differences between domain-specific models, with facilities for graphical visualization of the detected differences.     

BPMN 2.0编排的形式语义和分析

BPMN 2.0编排已成为描述业务流程间交互事实上的标准.BPMN 2.0编排面向流的特征,使之会产生控制流方面的语义错误.因此,检查编排语义正确性是BPMN 2.0编排建模工具所期望具有的功能.但是,BPMN 2.0标准规约中编排缺少形式语义及相应的分析技术,这阻碍了对BPMN 2.0编排的语义分析.本文提出了一种映射,用于将BPMN 2.0编排转换为工作流网,使用Petri网来形式定义BPMN 2.0编排的语义.借助Petri网的分析技术,这种定义的语义可用来分析BPMN 2.0编排的结构和控制流方面的错误.该映射和语义分析已被实现为一种工具.实验结果表明,这种形式化可以识别BPM AI过程模型库中编排的语义错误.     

UML2．0顺序图的XYZ／E时序逻辑语义研究

UML2．0顺序图适合于描述软件体系结构的各个组件之间和复合组件内部各个子组件之间的动态交互行为，但由于UML2．0顺序图的语义不够精确，使得它的描述结果不利于进一步的分析和验证。基于此，本文在定义UML2．0顺序图的语法和语法约束的基础上，给出了UML2．0顺序图的XYZ／E时序逻辑语义，为使用UML2．0顺序图与XYZ／E相结合的方式来描述软件体系结构的动态交互行为奠定了基础。