SPHINX: Schema integration by example

The Internet has instigated a critical need for automated tools that facilitate integrating countless databases. Since nontechnical end users are often the ultimate repositories of the domain information required to distinguish differences in data types, an effective solution must integrate simple GUI based data browsing tools and automatic mapping methods that eliminate the requirement for a technical user to supervise the process. We develop a metamodel of data integration as the basis for absorbing feedback from an end user. The schema integration algorithm draws examples from the data and learns integrating view definitions by asking a user simple yes or no questions. The metamodel enables a search mechanism that is guaranteed to converge to a correct integrating view definition without the user having to know a view definition language such as SQL or SchemaSQL, or even having to inspect the final view definition. We show how data catalog statistics, normally used to optimize queries, can be exploited to parameterize the search heuristics and improve the convergence of the learning algorithm.     

一种以活动为中心的软件过程元模型

在软件开发过程中，过程定义是整个软件过程工程的核心，而成功的过程定义基于一个良好的软件过程元模型。提出了一种以活动为中心的软件过程元模型，使用ECA规则处理多种活动之间的转移关系，该元模型的描述基于XML语言，并采用XML schema来定义和检查XML文档的语法。该元模型具有可操作性强、结构简单的特点，并且在实际软件开发中得到了初步应用。     

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).     

Space partitioning in piecewise metamodeling: a graphical approach

This paper presents a graphically-based space-partitioning methodology for piecewise metamodel building. The method is based on using data displays—in particular, the so-called ordinal plots—leading to a metamodel with acceptable prediction accuracy on a piece-by-piece basis, not just on average. The proposed methodology is general and can be applied to various metamodel types. A one-dimensional example is first used to demonstrate the approach, then the methodology is tested on a number of analytical examples in higher dimensions, one of which corresponds to an electronic filter.     

An approximate optimization strategy using refined hybrid metamodel

An approximate model called metamodel or surrogate model is a mathematical model that numerically approximates response of a system during an engineering simulation process or test. The introduction of a metamodel makes it possible to express response defined in the design problem as a simple mathematical function of design variables. A metamodel can be built with response surface method (RSM), kriging, neural network, radial basis function, and so on. Each method has its advantages and disadvantages. A combined metamodel called hybrid model, ensemble model, or multiple surrogates has been developed to maximize each metamodel's strength. The hybrid model of this research includes RSM and kriging. Besides, a strategy to refine the hybrid metamodel is implemented by reducing design space. In this process, information related to Hessian is utilized for an unconstrained optimization problem, on the contrary feasibility for a constrained optimization problem. This research presents a new hybrid metamodel-based optimization strategy called refined hybrid metamodel. Five mathematical test problems, two-bar design, spring design, and propeller shaft design problems are solved with the suggested method, verifying its usefulness. Most of the optimal results with the proposed method are closer to exact solutions with smaller function evaluations than existing methods.     

A Kriging-based algorithm to optimize production systems approximated by analytical models

Production system optimization still remains a difficult problem even if fast analytical methods are used to estimate their mean performance measures. This paper addresses optimization problems in which the system performance measures are obtained from analytical methods implemented in computer codes that are usually time expensive. A global search algorithm is proposed to solve the addressed optimization problem. A Kriging metamodel is built to approximate the system performance function on the basis of the deterministic output values provided by the analytical model. Then a standard optimization method is applied on the explicit metamodel expression. The main advantages of the proposed method are its generality and ease of use. Indeed, the algorithm can be applied to optimize any production system assessable by an analytical method. Also, the Kriging technique allows contemporarily building the approximation of the unknown function and assessing its quality. Numerical results are satisfactory and prove the applicability of the method to real problems.     

From UML/OCL to SBVR specifications: A challenging transformation

UML is currently the most widely used modeling language for the specification of the conceptual schema (CS) of an information system (IS). However, UML falls short when it comes to allow business people to define in their own language (e.g. using their own terms in natural language) the policies and rules by which they run their business. To this purpose, the semantics of business vocabulary and business rules (SBVR) metamodel specification was proposed. SBVR is conceptualized optimally for business people and it is designed to be used for business purposes, independently of information systems designs.     

An intelligent sampling approach for metamodel-based multi-objective optimization with guidance of the adaptive weighted-sum method

In order to reduce the computational cost of multi-objective optimization (MOO) with expensive black-box simulation models, an intelligent sampling approach (ISA) is proposed with the guidance of the adaptive weighted-sum method (AWS) to construct a metamodel for MOO gradually. The initial metamodel is built by using radial basis function (RBF) with Latin Hypercube Sampling (LHS) to distribute samples over the design space. An adaptive weighted-sum method is then employed to obtain the Pareto Frontier (POF) efficiently based on the metamodel constructed. The design variables related to extreme points on the frontier and an extra point interpolated between the maximal-minimal-distance point along the frontier and the nearest boundary point are selected as the concerned points to update the metamodel, which could improve the metamodel accuracy gradually. This iterative updating strategy is performed until the optimization problem is converged. A series of representative mathematical examples are systematically investigated to demonstrate the effectiveness of the proposed method, and finally it is employed for the design of a bus body frame.     

Engineering Methods from Method Requirements Specifications

By analogy with a Software Requirements Specification (SRS), it is argued that a Method Requirements Specification (MRS) should be introduced in method engineering. It shares with the SRS the property of implementation-independence. This means that an MRS must be an instance of an abstract metamodel and not of a technical metamodel like GOPRR (Graph, Object, Property, Relationship, and Role). The MRS is then translated to be an instantiation of a technical metamodel. We develop a representation system for an MRS and describe an automated process for instantiating a technical metamodel with an MRS. This instantiation is used to produce the actual method which is then given to a metaCASE to produce a CASE tool. Thus, we propose a method engineering approach rooted in the MRS.     

基于元模型的QoS管理模型

将元模型的思想应用于Qos管理，分析了定义Qos元模型所需的基本元素，研究了基于XML的元模型实现和应用方法，从而建立起开放的、可扩展的Qos表示体系。利用Qos表示体系，抽象出Qos空间、Qos水平及Qos状态的概念，在此基础上，结合模糊逻辑格运算，探讨了Oos适配管理的实现方式和具体算法。     

Process Metamodelling and Process Construction: Examples Using the OPEN Process Framework (OPF)

Deriving a unique software development process is not possible since the requirements of individual projects vary significantly. What is possible is a standard framework, defined by a metamodel, which can then provide an extensible and tailorable process environment such that individual and project-specific processes can be created and configured precisely to those project needs. As an illustration of this approach, the OPEN Process Framework (OPF) is described in terms of its underpinning metamodel. The use of this framework to construct individual process instances is then described, first in principle and then illustrated by three case studies: a process for mid-sized MIS development; a process for Web development; and a process to assist organizations in transitioning from a non-OO to an OO development culture.     

模式矩阵的理论研究Ⅰ：基本概念

本文在文献［２］、［３］的基础上，给出了模式矩阵的定义，分析并给出了模式矩阵的固有性质，特别对同类标准型详细讨论了它的分类，并讨论了各类的结构特征，为模式矩阵的理论研究提供了基础。     

Using enterprise architecture and technology adoption models to predict application usage

Application usage is an important parameter to consider in application portfolio management. This paper presents an enterprise architecture analysis framework which can be used to assess application usage. The framework, in the form of an architecture metamodel, incorporates variables from the previously published Technology Acceptance Model (TAM) and the Task-Technology Fit (TTF) model. The paper describes how the metamodel has been tailored for a specific domain, viz. industry maintenance management. The metamodel was tested in the maintenance management domain through a survey with 55 respondents at five companies. Data collected in the survey showed that the domain-specific metamodel is able to explain variations in maintenance management application usage. Integrating the TAM and TTF variables with an architecture metamodel allows architects to reuse research results smoothly, thereby aiding them in producing good application portfolio decision-support.     

一种基于动作语义的UML1.X-2.0模型转换方法

虽然UML2.0标准被OMG组织采纳已久,但由于UML1.X标准在工业界的广泛使用,仍然存在大量的实用模型和应用软件,它们在UML2.0标准之下已不能准确描述系统.UML2.0建模工具并不支持从UML1.X模型到UML2.0模型的转换.从顶层元模型的角度比较了这两个版本的不同,采用声明式和命令式混合的模型框架,给出了一种基于动作语义的UML模型转换方法,并用ASL描述交互元模型的转换实例,验证了方法的可行性.该方法将减少用户的重复劳动,实现软件的模型重用,也适用于其他元模型或模型层次上的转换.     

A transformation model from DEVS to SMP2 based on MDA

Simulation Model Portability standard 2 (SMP2) is a successful simulation model reuse standard in European Space Agency. Discrete Event System Specification (DEVS) is one of most common and powerful simulation model formalisms. Transforming a simulation model from DEVS representation to SMP2 representation is of great significance for model reuse. A Model Driven Architecture (MDA) based transformation methodology is presented first. According to this methodology, a MOF based DEVS metamodel is created and the mappings from DEVS metamodel to SMP2 metamodel are established. A transformation model from DEVS to SMP2 is described based on Query/View/Transformation (QVT) language. An illustrative example is detailed to demonstrate the application of the transformation model. The transformation model’s further application strategy and our next work are discussed in the final part.     

An algebraic semantics for MOF

In model-driven development, software artifacts are represented as models in order to improve productivity, quality, and cost effectiveness. In this area, the meta-object facility (MOF) standard plays a crucial role as a generic framework within which a wide range of modeling languages can be defined. The MOF standard aims at offering a good basis for model-driven development, providing some of the building concepts that are needed: what is a model, what is a metamodel, what is reflection in the MOF framework, and so on. However, most of these concepts are not yet fully formally defined in the current MOF standard. In this paper we define a reflective, algebraic, executable framework for precise metamodeling based on membership equational logic (mel) that supports the MOF standard. Our framework provides a formal semantics of the following notions: metamodel, model, and conformance of a model to its metamodel. Furthermore, by using the Maude language, which directly supports mel specifications, this formal semantics is executable. This executable semantics has been integrated within the Eclipse modeling framework as a plugin tool called MOMENT2. In this way, formal analyses, such as semantic consistency checks, model checking of invariants and LTL model checking, become available within Eclipse to provide formal support for model-driven development processes.