Model theory approach to transaction processing system development

This paper presents a new approach, model theory approach, to small and medium scale transaction processing system (TPS) development. A TPS of this paper is an information system designed to process day-to-day business event data at operational level of an organization. The paper is not concerned with data base construction but with transaction processing.

The model theory approach is not a software engineering approach but a systems theory approach. In the approach a model of the target system, which is called a user model, is constructed in set theory using a formal system structure of a TPS. The user model is, then, compiled into an extended Prolog (extProlog) model. The extProlog is an extension of Prolog to meet requirements for management information system development. On compilation a standardized user interface (UI) called internal UI is attached. The extProlog model with the internal UI is, then, executed under control of another standardized UI called an external UI. Implementation is an integral part of the approach. Because the UIs are designed for the formalized (abstract) structure of a TPS, they can be standardized and are provided as black box components to system development. Because a systems developer is required to only build a user model in set theory based on a model theoretic structure in the approach, it is called a model theory approach. Advantages of this approach are that it provides a theoretical structure to information systems development so that systems development can be made an engineering discipline, and facilitates rapid systems development.     

运用UML和XML构建通用远程教育系统的研究

针对目前各远程教育系统的资源描述和系统模型自成体系,无法实现教育资源的共享和系统的复用等问题,提出运用UML为系统建模,探讨用XML Schema定义描述教育资源XML文件的数据模型来实现教育资源元数据的互操作性,对远程教育系统中提高教育资源的可共享性和系统的互操作性以及可复用性具有重要的理论价值和实用性.     

Bridging the model-to-code abstraction gap with fuzzy logic in model-based regression test selection

Regression test selection (RTS) approaches reduce the cost of regression testing of evolving software systems. Existing RTS approaches based on UML models use behavioral diagrams or a combination of structural and behavioral diagrams. However, in practice, behavioral diagrams are incomplete or not used. In previous work, we proposed a fuzzy logic based RTS approach called FLiRTS that uses UML sequence and activity diagrams. In this work, we introduce FLiRTS 2, which drops the need for behavioral diagrams and relies on system models that only use UML class diagrams, which are the most widely used UML diagrams in practice. FLiRTS 2 addresses the unavailability of behavioral diagrams by classifying test cases using fuzzy logic after analyzing the information commonly provided in class diagrams. We evaluated FLiRTS 2 on UML class diagrams extracted from 3331 revisions of 13 open-source software systems, and compared the results with those of code-based dynamic (Ekstazi) and static (STARTS) RTS approaches. The average test suite reduction using FLiRTS 2 was 82.06%. The average safety violations of FLiRTS 2 with respect to Ekstazi and STARTS were 18.88% and 16.53%, respectively. FLiRTS 2 selected on average about 82% of the test cases that were selected by Ekstazi and STARTS. The average precision violations of FLiRTS 2 with respect to Ekstazi and STARTS were 13.27% and 9.01%, respectively. The average mutation score of the full test suites was 18.90%; the standard deviation of the reduced test suites from the average deviation of the mutation score for each subject was 1.78% for FLiRTS 2, 1.11% for Ekstazi, and 1.43% for STARTS. Our experiment demonstrated that the performance of FLiRTS 2 is close to the state-of-art tools for code-based RTS but requires less information and performs the selection in less time.

     

On evaluating the layout of UML diagrams for program comprehension

UML class and sequence diagrams are helpful for understanding the static structure and dynamic behavior of a software system. Algorithms and tools have been developed to generate these UML diagrams automatically for program understanding purposes. Many tools, however, often ignore perceptual factors in the layout of these diagrams. Therefore, users still have to spend much time and effort rearranging boxes and lines to make the diagram understandable. This article presents key criteria and guidelines for the effective layout of UML class and sequence diagrams from the perspective of perceptual theories. Two UML tools are evaluated to illustrate how the criteria can be applied to assess the readability of their generated diagrams. Kenny Wong is an Associate Professor in the Department of Computing Science at the University of Alberta. His main areas of research include software comprehension, evolution, and visualization. This research includes building, using, and evaluating integrated environments for reverse engineering, and devising strategies to understand and evolve diverse software systems. He is General Chair of the 2007 International Conference on Program Comprehension in Banff, and Program Chair of the 2008 International Conference on Software Maintenance in Beijing. Dabo Sun is an M.Sc. student in the Department of Computing Science at the University of Alberta. His research interests include program comprehension, software visualization, and end-user software engineering. He has assisted the teaching of courses in software engineering and web information systems. He also has been working as a software engineer on developing and maintaining industrial software systems.     

Semi-formal transformation of secure business processes into analysis class and use case models: An MDA approach

ContextModel-Driven Development (MDD) is an alternative approach for information systems development. The basic underlying concept of this approach is the definition of abstract models that can be transformed to obtain models near implementation. One fairly widespread proposal in this sphere is that of Model Driven Architecture (MDA). Business process models are abstract models which additionally contain key information about the tasks that are being carried out to achieve the company’s goals, and two notations currently exist for modelling business processes: the Unified Modelling Language (UML), through activity diagrams, and the Business Process Modelling Notation (BPMN).ObjectiveOur research is particularly focused on security requirements, in such a way that security is modelled along with the other aspects that are included in a business process. To this end, in earlier works we have defined a metamodel called secure business process (SBP), which may assist in the process of developing software as a source of highly valuable requirements (including very abstract security requirements), which are transformed into models with a lower abstraction level, such as analysis class diagrams and use case diagrams through the approach presented in this paper.MethodWe have defined all the transformation rules necessary to obtain analysis class diagrams and use case diagrams from SBP, and refined them through the characteristic iterative process of the action-research method.ResultsWe have obtained a set of rules and a checklist that make it possible to automatically obtain a set of UML analysis classes and use cases, starting from SBP models. Our approach has additionally been applied in a real environment in the area of the payment of electrical energy consumption.ConclusionsThe application of our proposal shows that our semi-automatic process can be used to obtain a set of useful artifacts for software development processes.     

Empirical studies concerning the maintenance of UML diagrams and their use in the maintenance of code: A systematic mapping study

ContextThe Unified Modelling Language (UML) has, after ten years, become established as the de facto standard for the modelling of object-oriented software systems. It is therefore relevant to investigate whether its use is important as regards the costs involved in its implantation in industry being worthwhile.MethodWe have carried out a systematic mapping study to collect the empirical studies published in order to discover “What is the current existing empirical evidence with regard to the use of UML diagrams in source code maintenance and the maintenance of the UML diagrams themselves?ResultsWe found 38 papers, which contained 63 experiments and 3 case studies.ConclusionAlthough there is common belief that the use of UML is beneficial for source code maintenance, since the quality of the modifications is greater when UML diagrams are available, only 3 papers concerning this issue have been published. Most research (60 empirical studies) concerns the maintainability and comprehensibility of the UML diagrams themselves which form part of the system’s documentation, since it is assumed that they may influence source code maintainability, although this has not been empirically validated. Moreover, the generalizability of the majority of the experiments is questionable given the material, tasks and subjects used. There is thus a need for more experiments and case studies to be performed in industrial contexts, i.e., with real systems and using maintenance tasks conducted by practitioners under real conditions that truly show the utility of UML diagrams in maintaining code, and that the fact that a diagram is more comprehensible or modifiable influences the maintainability of the code itself. This utility should also be studied from the viewpoint of cost and productivity, and the consistent and simultaneous maintenance of diagrams and code must also be considered in future empirical studies.     

Manual test case derivation from UML activity diagrams and state machines: A controlled experiment

ContextIt is a difficult and challenging task to fully automatize model-based testing because this demands complete and unambiguous system models as input. Therefore, in practice, test cases, especially on the system level, are still derived manually from behavioral models like UML activity diagrams or state machines. But this kind of manual test case derivation is error-prone and knowing these errors makes it possible to provide guidelines to reduce them.ObjectiveThe objective of the study presented in this paper therefore is to examine which errors are possible and actually made when manually deriving test cases from UML activity diagrams or state machines and whether there are differences between these diagram types.MethodWe investigate the errors made when deriving test cases manually in a controlled student experiment. The experiment was performed and internally replicated with overall 84 participants divided into three groups at two institutions.ResultsAs a result of our experiment, we provide a taxonomy of errors made and their frequencies. In addition, our experiment provides evidence that activity diagrams have a higher perceived comprehensibility but also a higher error-proneness than state machines with regard to manual test case derivation. This information helps to develop guidelines for manual test case derivation from UML activity diagrams and state machines.ConclusionMost errors observed were due to missing test steps, conditions or results, or content was written into the wrong field. As activity diagrams have a higher perceived comprehensibility, but also more error-prone than state machines, both diagram types are useful for manual test case derivation. Their application depends on the context and should be complemented with clear rules on how to derive test cases.     

基于Web日志的数据挖掘研究

针对当前Web日志数据信息越来越多的问题,传统的数据库管理系统无法对其进行有效的操作分析。采用数据挖掘技术对其进行研究,从数据挖掘的系统结构和数据挖掘的过程两个方面对数据挖掘进行描述;对Web日志挖掘的理论和过程进行了详细的分析;给出ID3算法的描述,并给出了部分核心的代码。     

PDM system implementation based on UML

The paper deals with a Unified Modeling Language (UML)-based approach for implementing Product Data Management (PDM) system. Such kind of system enables the management of the entire product lifecycle and related information about its design, its manufacturing and its in-service.

The interest of using an UML-based approach for modeling, specifying and implementing PDM systems is detailed. Then an implementation method is proposed in order to clarify the instantiation of UML diagrams into database entities. Regarding a business case study based on the needs of a turboprop aircraft development project, the preliminary implementation of PDM system is presented. The used UML diagrams for the modeling and integration of product, process, and resource data is detailed in order to argue the interest of an object-oriented approach in such kind of PDM implementation.     

Static generation of UML sequence diagrams

UML sequence diagrams are visual representations of object interactions in a system and can provide valuable information for program comprehension, debugging, maintenance, and software archeology. Sequence diagrams generated from legacy code are independent of existing documentation that may have eroded. We present a framework for static generation of UML sequence diagrams from object-oriented source code. The framework provides a query refinement system to guide the user to interesting interactions in the source code. Our technique involves constructing a hypergraph representation of the source code, traversing the hypergraph with respect to a user-defined query, and generating the corresponding set of sequence diagrams. We implemented our framework as a tool, StaticGen (supporting software: StaticGen), analyzing a corpus of 30 Android applications. We provide experimental results demonstrating the efficacy of our technique (originally appeared in the Proceedings of Fundamental Approaches to Software Engineering—20th International Conference, FASE 2017, Held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2017, Uppsala, Sweden, April 22–29, 2017).

     

Model-based early and rapid estimation of COSMIC functional size – An experimental evaluation

ContextFunctional size measurement methods are widely used but have two major shortcomings: they require a complete and detailed knowledge of user requirements, and they involve relatively expensive and lengthy processes.ObjectiveUML is routinely used in the software industry to effectively describe software requirements in an incremental way, so UML models grow in detail and completeness through the requirements analysis phase. Here, we aim at defining the characteristics of increasingly more refined UML requirements models that support increasingly more sophisticated – hence presumably more accurate – size estimation processes.MethodWe consider the COSMIC method and three alternative processes (two of which are proposed in this paper) to estimate COSMIC size measures that can be applied to UML diagrams at progressive stages of the requirements definition phase. Then, we check the accuracy of the estimates by comparing the results obtained on a set of projects to the functional size values obtained with the standard COSMIC method.ResultsOur analysis shows that it is possible to write increasingly more detailed and complete UML models of user requirements that provide the data required by COSMIC size estimation methods, which in turn yield increasingly more accurate size measure estimates of the modeled software. Initial estimates are based on simple models and are obtained quickly and with little effort. The estimates increase their accuracy as models grow in completeness and detail, i.e., as the requirements definition phase progresses.ConclusionDevelopers that use UML for requirements modeling can obtain an early estimation of the application size at the beginning of the development process, when only a very simple UML model has been built for the application, and can obtain increasingly more accurate size estimates while the knowledge of the product increases and UML models are refined accordingly.     

基于UML类图模型的一致性检查方法

UML中的类图采用直观的图形化表示方法,有效描述了待建系统的静态特征,为系统设计人员发现系统模型中存在的不一致性和冗余等问题,提供了有效的分析工具。但是对于复杂的系统,完全依靠系统分析人员发现模型中存在的不一致性和冗余等问题是不现实的,应当为建模工具赋以模型自动一致性检查功能。SHOIQ(D)是描述逻辑家族中可判定的子集,它在保证推理可判定的同时,具备较强的描述知识能力。鉴于上述特点,通过从UML类图图元中抽取语义,用SHOIQ(D)形式化描述类图图元,借助自动推理引擎,从而使基于UML类图模型的自动一致性检查功能得到实现。根据该方法改进后的建模工具,可以自动发现基于UML类图模型中存在的不一致性和冗余等问题。     

扩展UML活动图在工作流建模中的应用*

针对UML对数据和信息流描述缺乏充分表达业务工作流程的问题,借助新创建的活动图,提出了基于扩展UML活动图的工作流过程建模方法。应用实例表明,扩展的UML活动图对工作流程的语义表达更丰富,更准确地描述工作流建模所需表达的内容,以满足工作流过程建模的要求。     

Combining UML, ASTD and B for the formal specification of an access control filter

Combination of formal and semi-formal methods is more and more required to produce specifications that can be, on the one hand, understood and thus validated by both designers and users and, on the other hand, precise enough to be verified by formal methods. This motivates our aim to use these complementary paradigms in order to deal with security aspects of information systems. This paper presents a methodology to specify access control policies starting with a set of graphical diagrams: UML for the functional model, SecureUML for static access control and ASTD for dynamic access control. These diagrams are then translated into a set of B machines. Finally, we present the formal specification of an access control filter that coordinates the different kinds of access control rules and the specification of functional operations. The goal of such B specifications is to rigorously check the access control policy of an information system taking advantage of tools from the B method.     

Model-driven specification and enforcement of RBAC break-glass policies for process-aware information systems

ContextIn many organizational environments critical tasks exist which – in exceptional cases such as an emergency – must be performed by a subject although he/she is usually not authorized to perform these tasks. Break-glass policies have been introduced as a sophisticated exception handling mechanism to resolve such situations. They enable certain subjects to break or override the standard access control policies of an information system in a controlled manner.ObjectiveIn the context of business process modeling a number of approaches exist that allow for the formal specification and modeling of process-related access control concepts. However, corresponding support for break-glass policies is still missing. In this paper, we aim at specifying a break-glass extension for process-related role-based access control (RBAC) models.MethodWe use model-driven development (MDD) techniques to provide an integrated, tool-supported approach for the definition and enforcement of break-glass policies in process-aware information systems. In particular, we provide modeling support on the computation independent model (CIM) layer as well as on the platform independent model (PIM) and platform specific model (PSM) layers.ResultsOur approach is generic in the sense that it can be used to extend process-aware information systems or process modeling languages with support for process-related RBAC and corresponding break-glass policies. Based on the formal CIM layer metamodel, we present a UML extension on the PIM layer that allows for the integrated modeling of processes and process-related break-glass policies via extended UML Activity diagrams. We evaluated our approach in a case study on real-world processes. Moreover, we implemented our approach at the PSM layer as an extension to the BusinessActivity library and runtime engine.ConclusionOur integrated modeling approach for process-related break-glass policies allows for specifying break-glass rules in process-aware information systems.     

一种UML 软件架构性能预测方法及其自动化研究

软件性能需求作为软件质量需求的重要组成部分,已受到人们极大的重视.而只在软件开发周期后期才重点关注软件性能需求的传统软件开发方法,将给开发者带来高风险和高成本等后果.如果能在软件开发周期的早期对软件系统性能进行预测,可以提前发现软件系统架构存在的性能瓶颈,并找出可能的优化方案,对各种设计方案进行比较以得出最优的软件系统架构.研究了一种基于模型的UML 软件架构性能预测方法:该方法选取软件架构设计中的UML 用例图、活动图和构件图,并引入构造型和标记值,将它们扩展为UML SPT 模型;进而,通过转换算法将UML SPT 模型转换为排队网络模型,该算法可处理同时包含分支节点和汇合节点的UML 模型活动图;最后,利用频域分析理论求解排队网络模型,以得出性能参数及性能瓶颈.同时介绍了UML 软件架构性能自动化工具的设计方案,并给出了软件架构性能预测实例.     

Does the level of detail of UML diagrams affect the maintainability of source code?: a family of experiments

Although the UML is considered to be the de facto standard notation with which to model software, there is still resistance to model-based development. UML modeling is perceived to be expensive and not necessarily cost-effective. It is therefore important to collect empirical evidence concerning the conditions under which the use of UML makes a practical difference. The focus of this paper is to investigate whether and how the Level of Detail (LoD) of UML diagrams impacts on the performance of maintenance tasks in a model-centric approach. A family of experiments consisting of one controlled experiment and three replications has therefore been carried out with 81 students with different abilities and levels of experience from 3 countries (The Netherlands, Spain, and Italy). The analysis of the results of the experiments indicates that there is no strong statistical evidence as to the influence of different LoDs. The analysis suggests a slight tendency toward better results when using low LoD UML diagrams, especially if used for the modification of the source code, while a high LoD would appear to be helpful in understanding the system. The participants in our study also favored low LoD diagrams because they were perceived as easier to read. Although the participants expressed a preference for low LoD diagrams, no statistically significant conclusions can be drawn from the set of experiments. One important finding attained from this family of experiments was that the participants minimized or avoided the use of UML diagrams, regardless of their LoD. This effect was probably the result of using small software systems from well-known domains as experimental materials.