基于元模型的HBase数据模型转换方法

模型驱动架构方法（MDA）可以减少需求变更对软件开发的影响,提高软件开发效率和系统的可移植性、可维护性。本文在MDA思想的基础上,建立平台无关模型和平台相关模型的元模型,在元模型层次上提出UML类图模型到HBase数据模型的转换思想。最后,在ATL模型转换框架中实现UML类图模型到HBase数据模型的转换,证明了自动生成数据库目标模型和MDA在软件开发中的可行性。      

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.     

一种模型转换的编织框架

模型转换是MDA(model driven architecture)的核心技术之一,也是目前MDA研究的热点.目前,MDA范畴内存在多种模型转换方法和工具,它们之间的异构性造成了模型转换代码重用的困难,并使学习和使用模型转换方法的成本增加.受到模型编织技术的启发,提出了一种基于QVT(model query/view/transformation)规范的模型转换编织框架QMTW(QVT-based model transformation weaving framework)来解决以上缺点.展示了模型转换编织的概念、语义、元模型和语法,以及到目标语言的转换定义,并以一个具体实例说明了本框架的使用方法和优点.QMTW提高了模型转换的抽象层次,统一了多种模型转换语言,并支持OMG最新的模型转换规范,在一定程度上消除了模型转换技术的异构性,同时具有简单、规范、扩展性强3个优点.     

基于MDA的UML模型转换:从功能模型到实现模型

MDA（Model Drive Architecture）是OMG（Object Management Group）提出的解决系统集成问题的新途径,它以UML、MOF、CWM为核心,定义软件开发过程中的模型组织管理框架。本文探讨了MDA框架下在元模型层定义模型转换的方法。引入模型转换规则描述语言,给出模型转换规则应遵循的部分原则。以CORBA平台为例说明在元模型层用既定语言定义模型转换规则,从功能模型到实现模型的模型转换方法。基于以上方法构建相应的工具原型。     

基于本体映射的MDA模型转换研究

模型转换是MDA框架中的重要环节之一,以往的模型转换方法可能会因为缺乏语义保证而出现错误。本文通过本体映射来研究MDA模型转换,提出实现MDA模型语义层转换的方法,并提高模型转换的效率和准确率。     

面向Hyperledger Fabric的SQL访问框架

区块链技术具有去中心化、不可篡改、可追溯等优势,已经在各领域得到广泛应用.但区块链作为一项前沿技术,存在开发难度大、学习成本高等问题,且大多数开发者更熟悉基于关系型数据库的应用开发方法,即通过SQL操作关系型数据库.Hyperledger Fabric是目前最为主流的区块链开发框架.针对此问题,文中提出了一种面向Hyperledger Fabric的SQL访问框架.首先,针对Fabric和SQL底层存储结构不一致的问题,定义了关系模型至键值模型的转换规则,实现了模型转换算法;然后,基于智能合约技术开发了 SQL执行合约,实现了 SQL语句向底层状态数据库CouchDB操作语句的自动转换,进而操作Fabric底层的数据;最后,从应用层开发的角度,设计了应用自动化重构工具,工具包含两个部分,分别是应用重构工具和区块链网络的交互中间件Fabric-Driver.实验结果表明,相比现有方案,使用所提框架开发区块链应用能节省82％左右的时间,且使用此框架降低的读写性能仅有5％左右.     

基于MDA的设计模式建模与模型转换

MDA(model driven architecture)的一个重要意图是将模型作为软件开发的基本单元,以进一步提高软件开发的抽象层次.为此,MDA划分了3种抽象级的模型,并通过建立高抽象级的模型和向低抽象级模型及代码的转换来构造可运行的应用程序.在MDA的框架下,将设计模式作为一种独立的建模和转换单元能够在较高的抽象层次上充分支持复用并提高建模粒度,从而进一步发挥设计模式的优点,提高软件开发效率、降低生产成本.然而,要在MDA的框架下将设计模式作为完整的开发单元来使用,必须解决以模式为单元的建模及转换两个具体问题.针对单元化模式建模的问题,通过扩展MOF(meta object facility)的方式定义了模式单元元模型,并提供了基于此元模型的单元化建模支撑机制,以分离业务模型与模式模型的方式解决了该问题.针对单元化模式模型转换问题,在模式单元元模型的基础上定义了向EJB平台的转换规则.该转换规则使用QVT标准描述,支持单元化的模式模型转换,并具有良好的复用性.     

一种支持多目标框架的模型驱动开发方法

平台无关模型到平台相关模型的转换是OMG提出的模型驱动架构(MDA)中的关键技术。目前多数开发工具将平台相关模型定义为具体的目标运行框架,这严重降低了软件演化过程中设计模型的可重用性。为此,引入抽象平台相关模型和具体平台相关模型的概念,使基于某种平台的业务逻辑设计与目标运行框架相分离,提出一种支持多目标框架代码生成的扩展MDA开发模型。实验证明,该方法提升了模型描述的灵活性和可重用性,能够对模型驱动的软件开发提供有力的支持。     

UML模型到N层Web模型的模型驱动转换

模型驱动架构(MDA)是由对象管理组织(OMG)提出的应用模型技术进行软件开发的方法和标准体系,其核心理念是平台无关模型建模和平台特定模型转换。通过编程实现基于元对象机制2.0(MOF2.0)查询/视图/转换(QVT)标准定义开发的框架,该框架可以将元模型转换为特定N层应用程序类,实现主要程序功能,从而大大提高开发效率。验证了通过编程实现模型驱动转换的灵活性和功能实现的多样性,包括XML文件对模型规范的描述以及生成代码的完整性。     

基于有限状态机的模型转换方法的研究

模型转换是MDA框架中最重要的组成部分之一,因此,对模型转换方法的研究非常重要。为了促进MDA框架理论的发展以及探索更有效的模型转换机制,文中对模型转换方法做了较深入的研究。文中通过对有限状态机的分类和有限状态机的工作原理的介绍,并把有限状态机的理论应用到模型转换中,从而提出了基于有限状态机的模型转换方法。文中从以下几个方面对基于有限状态机的模型转换方法进行了较深入的分析与研究,主要包括转换元模型的定义、模型转换中的有限状态机的描述和可逆向操作的状态生成算法。文中提出的方法为有着比较明显的状态变化的模型之间的相互转换提供了一种比较方便的模型转换实施方案,同时对其它模型转换方法也有一定的参考价值。     

Feature extraction using discrete cosine transform and discrimination power analysis with a face recognition technology

Discrete cosine transform (DCT) is a powerful transform to extract proper features for face recognition. After applying DCT to the entire face images, some of the coefficients are selected to construct feature vectors. Most of the conventional approaches select coefficients in a zigzag manner or by zonal masking. In some cases, the low-frequency coefficients are discarded in order to compensate illumination variations. Since the discrimination power of all the coefficients is not the same and some of them are discriminant than others, so we can achieve a higher true recognition rate by using discriminant coefficients (DCs) as feature vectors. Discrimination power analysis (DPA) is a statistical analysis based on the DCT coefficients properties and discrimination concept. It searches for the coefficients which have more power to discriminate different classes better than others. The proposed approach, against the conventional approaches, is data-dependent and is able to find DCs on each database. The simulations results of the various coefficient selection (CS) approaches on ORL and Yale databases confirm the success of the proposed approach. The DPA-based approaches achieve the performance of PCA/LDA or better with less complexity. The proposed method can be implemented for any feature selection problem as well as DCT coefficients. Also, a new modification of PCA and LDA is proposed namely, DPA-PCA and DPA-LDA. In these modifications DCs which are selected by DPA are used as the input of these transforms. Simulation results of DPA-PCA and DPA-LDA on the ORL and Yale database verify the improvement of the results by using these new modifications.     

Validating functional equivalence of re-engineered programs via control path,result, and data flow comparison

A combination of three approaches is proposed here to validate the functional equivalence of re-engineered programs. These are: control path comparison; data result comparison; and data flow comparison. Two of the three approaches are based on the theory of program slicing. The third approach is based on the theory of data invariance, i.e. the same input must produce the same output. Together, these techniques can provide a cost effective regression test environment for large scale re-engineering projects.     

Application of OLAP to a PDM database for interactive performance evaluation of in-progress product development

This paper applies online analytic processing (OLAP), a widely accepted database analysis technique, to a product data management (PDM) database to evaluate the performance of in-progress product development. This paper introduces a set of processing key performance indicators (KPIs) that can measure ongoing product development. To convert and analyze operational data in a PDM database with interactive OLAP operations, this study proposes a multidimensional data model specified by product facts with associated dimensions. The model is implemented using a commercial OLAP engine, and applied to a database supported by a prototype PDM system. The OLAP engine allows analysts to interactively evaluate the performance of in-progress product development in a multidimensional data space. This is a far more flexible and efficient approach than other result-oriented static evaluation approaches.     

On the Role of Metadata in Visual Language Reuse and Reverse Engineering – An Industrial Case

Collecting metadata on a family of programs is useful not only for generating statistical data on the programs but also for future re-engineering and reuse purposes. In this paper we discuss an industrial case where a project library is used to store visual programs and a database to store the metadata on these programs. The visual language in question is a domain-specific language, Function Block Language (FBL) that is used in Metso Automation for writing automation control programs. For reuse, program analysis and re-engineering activities and various data and program analysis methods are applied to study the FBL programs. Metadata stored in a database is used to provide advanced program analysis support; from the large amount of programs, the metadata allows focusing the analysis to certain kinds of programs. In this paper, we discuss the role and usage of the metadata in program analysis techniques applied to FBL programs.     

Cost models for future software life cycle processes: COCOMO 2.0

Current software cost estimation models, such as the 1981 Constructive Cost Model (COCOMO) for software cost estimation and its 1987 Ada COCOMO update, have been experiencing increasing difficulties in estimating the costs of software developed to new life cycle processes and capabilities. These include non-sequential and rapid-development process models; reuse-driven approaches involving commercial off-the-shelf (COTS) packages, re-engineering, applications composition, and applications generation capabilities; object-oriented approaches supported by distributed middleware; and software process maturity initiatives. This paper summarizes research in deriving a baseline COCOMO 2.0 model tailored to these new forms of software development, including rationale for the model decisions. The major new modeling capabilities of COCOMO 2.0 are a tailorable family of software sizing models, involving Object Points, Function Points, and Source Lines of Code; nonlinear models for software reuse and re-engineering; an exponentdriver approach for modeling relative software diseconomies of scale; and several additions, deletions and updates to previous COCOMO effort-multiplier cost drivers. This model is serving as a framework for an extensive current data collection and analysis effort to further refine and calibrate the model's estimation capabilities.     

Performance optimization of integrated job-driven and resilience factors by means of a quantitative approach

Job-driven factors affect overall productivity and describe the characteristics influencing human performance. Resilience engineering (RE) is the capability of systems and groups to cope with disturbances and disruptions to enhance their performance. This study employs data envelopment analysis (DEA) approach to optimize the overall performance of a ceramic tile company by considering resilience and job-driven factors. The required data were collected via a standard questionnaire whose reliability was examined by statistical methods. In this regard, sensitivity analysis was performed to determine the most important factors. DEA results showed that job stress, job burnout, and management commitment play a central role in the investigated system. The overall results indicated that job-driven factors have a higher weight than resilience factors. This is one of the first studies that concurrently examine job-driven and resilience factors. Second, the present study uses DEA method in a ceramic tile manufacturer to achieve optimum performance. Third, the weights of all factors are computed for optimum redesign and re-engineering. Fourth, decision-makers may identify weak areas and strong points of their systems with respect to job-driven and resilience factors.     

Java程序混淆技术综述

软件混淆技术已经广泛应用于抵制逆向工程和重组工程.文中从混淆技术的历史发展角度对现有的混淆技术理论、算法、攻击模式和评估进行了综述,将Java程序混淆算法分为类内混淆和类间混淆两个类别,并对其中的各类算法进行详尽的阐释.最后在现有工作的基础上,展望了软件混淆技术未来的发展与研究方向.