业务模型中的协同模型研究*

针对业务模型中对协同关系描述的不足,详细定义了协同模型,给出了从业务模型中的过程模型抽取协同模型的规则,并阐明了协同模型对业务模型中其他各模型的影响。     

一种数据模型的范畴论建模方法

针对数据模型复杂语义建模的应用需求, 以及目前数据模型范畴论建模方法理论研究与工程实践方面存在的不足, 建立了一种素描数据模型。该模型在模型范畴的形式化框架内, 用与特定数据库建模语言无关的范畴论对数据库状态的一致性转换进行了形式化描述, 扩展了传统ER模型的表示与处理功能。基于素描对图形化建模规范的支持, 设计了ER模型向素描数据模型转换的算法, 以精确的语义联系保证模型转换的语义完整性, 并通过实验与对比分析了素描数据模型与算法的优势, 为数据模型的范畴论建模方法研究提供便利、高效的形式化理论框架。     

OWL-S模型转化为重写逻辑模型的方法

OWL-S模型在基于服务的软件设计中具有重要作用,但由于其非完全形式化的模型,不能直接对其进行形式化分析与验证。基于OWL-S模型的重写逻辑语义框架,通过对数据类型、表达式、控制结构与Process的转换,设计并实现了OWL-S模型到重写逻辑模型的自动转化工具,为能够在软件实现前为设计模型的形式化分析与验证,以及可靠性分析提供基础。     

基于泛关系模型表示的层次化模型管理框架

针对常见模型表示方法缺少对多阶段建模过程支持,造成不同建模阶段模型难以统一管理、共享和重用的问题,提出基于泛关系模型表示的层次化模型管理框架。分析现有模型表示方法特点和多阶段建模过程中模型表示及管理需求,采用泛关系模型表示建立概念模型和数学模型表示方法之间映射关系,建立一体化模型表示方法和层次化模型管理框架; 研究层次化模型管理框架中概念层模型和泛关系层模型的模型库设计逻辑,并基于泛关系理论,研究了物理层模型的动态生成方法,实现了不同建模阶段模型的一体化表示和统一管理。     

Graph and model transformation tools for model migration

We describe the results of the Transformation Tool Contest 2010 workshop, in which nine graph and model transformation tools were compared for specifying model migration. The model migration problem—migration of UML activity diagrams from version 1.4 to version 2.2—is non-trivial and practically relevant. The solutions have been compared with respect to several criteria: correctness, conciseness, understandability, appropriateness, maturity and support for extensions to the core migration task. We describe in detail the comparison method, and discuss the strengths and weaknesses of the solutions with a special focus on the differences between graph and model transformation for model migration. The comparison results demonstrate tool and language features that strongly impact the efficacy of solutions, such as support for retyping of model elements. The results are used to motivate an agenda for future model migration research (including suggestions for areas in which the tools need to be further improved).     

将UML模型转换成SDL模型的方法

提出了一种将UML模型转换成SDL模型的方法.UML是一种优秀的建模语言,使用UML可以为协议建立模型带来很多方便.但是,UML缺乏形式化语义,因此不能满足协议精确性的要求.SDL是一种用于通信软件规格的标准语言,它拥有形式化语义,而且有很多商业软件都支持它.在协议设计和开发中,将UML模型转换成SDL模型可以克服这样的缺点.通过为UML制作适当的profile,并制定严格的转换规则可以实现模型的转换.     

Simulink模型到Modelica模型转换技术

针对Simulink模型重用到更高阶的Modelica平台上的需求,分析Simulink模型的数学本质和代码表达,以及Modelica对外部函数和外部类的支持,重用Simulink模型转换生成的S function目标C代码,实现Simulink模型到Modelica模型转换.     

基于元数据的地理模型与GIS的集成

从提高地理信息系统的地理应用分析功能,有效集成现有发展的各类模型和加强地学研究信息共享的角度出发,以元数据为桥梁,提出构建基于模型元数据的开放集成环境的思路。参考ISO有关规范,从9个方面规范并描述了地理应用模型标准文档应该提供的元数据信息。探讨了基于地理模型元数据进行集成的模式和模型元数据在集成中的机理与方法,并给出了相应的原型系统。所提出的基于元数据建立开放的集成环境,改变了集成系统中需要对GIS或者模型二者之一或者都进行改造的思路,具有一定的理论意义和实践指导价值。     

Equivalence of the generalized bond-energy model,the Wagner-Schottky-type model and the compound-energy model for ordered phases

The equivalence of three thermodynamic models used in the literature to describe the compositional and temperature dependencies of the thermodynamic properties of ordered intermetallic phases is presented. The three models are the generalized bond-energy model, the Wagner-Schottky-type model and the compound-energy model. Equations to convert the model parameters of the generalized bond-energy model to those of the other two models are derived. The validity of these equations is demonstrated by showing the successful conversion of the model parameters for the ordered phases in the Ti-Al system from the generalized bond-energy model to those of the Wagner-Schottky-type model and the compound-energy model. However, conversion of the model parameters from these two models to the generalized bond energy model is generally not possible due to additional constraints imposed in developing the later model.     

基于ALAP元模型的产品功能模型

针对当前产品功能建模理论没有覆盖智能设计完整生命周期的问题,提出应用—逻辑—算法—物理分层抽象模型（Application-Logic-Algorithm-Physics layer abstract model,ALAP）,将其作为产品功能模型的元模型,并阐述产品功能模型的构建流程;提出用于描述产品功能模型的功能对象方法树（Function Object Method Tree,FOMT）,并给出座椅设计描述的实例.ALAP具有一般性、开放性和通用性的特点,可为新的产品功能模型开发提供参考,也能规范已有模型,使不同模型之间可以通信.     

基于LDA的条件随机场主题模型研究

使用主题模型对文本建模,提取文本的隐含主题,进而进行词性标注和文本分类等工作,是机器学习和文本挖掘领域的研究热点。提出一个基于LDA的主题模型,它基于“段袋“假设--文本中的段落具有相同的主题,且连续的段落更倾向于具有相同的主题。对于文章的段落,采用条件随机场（CRF）模型划分并判断它们是否具有相同主题。实验表明,新模型相比LDA模型能更好得提取主题并具有更低的困惑度,同时,能够较好地进行词性标注和文本分类工作。     

基于作者主题模型和辐射模型的用户位置预测模型

由于全球定位系统（GPS）设备采集的用户历史位置数据通常具有稀疏性,使得基于单个用户数据的位置预测模型能力受限,所以结合人类移动性的时间和空间周期性,提出一种基于作者主题模型（ATM）和辐射模型（RM）的用户位置预测模型。在时间维度上,该模型利用ATM发现与目标用户移动行为相似的用户群,并确定该用户群在预测时刻所处的目标状态;在空间维度上,该模型利用RM算法计算目标用户的候选地点在目标状态下的概率,并通过比较各候选地点的概率值确定目标用户可能出现的地点,从而实现对目标用户位置的预测。实验结果表明,该模型的平均预测准确率为61.49%,相对于基于变阶的Markov模型提高近28个百分点。所提预测模型能够在单个用户数据量小的条件下获得更高的预测准确率。     

基于不完全朴素贝叶斯分类模型的垃圾邮件分类模型

由于朴素贝叶斯分类模型的简单高效,在垃圾邮件分类时可以达到较好的效果;但朴素贝叶斯的条件独立假设割裂了属性之间的关系,影响了分类的准确性。放松朴素贝叶斯分类模型关于属性之间条件独立假设,介绍一种新的基于不完全朴素贝叶斯分类模型的垃圾邮件分类模型,N平均1 依赖邮件过滤模型。使用N个1 依赖分类模型的平均概率作为分类的预测概率。实验证明,该模型在简单、高效的同时降低了对垃圾邮件分类的错误率。     

基于三层结构模型的类模型分析

类的构造是面向对象系统分析的难点,类的构造合理与否很大程度上决定了系统的成败.因此,在面向对象系统分析和设计过程中,类模型的分析是复杂的、重要的且容易重复劳动.为了降低设计过程的复杂性,减少重复性劳动,高效率且高质量地完成系统建模与设计,提出一种基于层次结构模型的类模型分析方法,并阐述了这种方法的机理;结合“移动学习系统的学生选课子系统”的开发实例,深入探讨了从类模型到层次结构模型的映射过程.     

Finite model order accuracy in Hammerstein model estimation

Hammerstein models is one of the most commonly used model classes used for identifying nonlinear systems. A static input nonlinearity followed by a linear dynamical part is an adequate way to model many real-life systems. This paper investigates the asymptotic (in terms of sample size) variance of Hammerstein model estimates. The work extends earlier results by Ninness and Gibson (2002) in the following ways. Not only frequency function estimation but estimation of general quantities is considered. The expressions are not restricted to be valid asymptotically in the model order. In addition, the results cover model structures having noise models and allow for data generated under feedback. The increase in variance due to the estimation of the input nonlinearity is characterized. In particular, under open loop operation, white additive noise and the assumption of a separable process, it is shown that the variance increase is exactly a term that was observed in Ninness and Gibson (2002) to result in good agreement with simulations. This term vanishes in the formal asymptotic in model order analysis in Ninness and Gibson (2002).     

一种扩展的使用控制模型及其实施模型*

指出了原有UCON模型缺乏对特定使用会话中资源使用之后的行为处理能力、过度简化了使用会话的概念以及缺乏一种综合考虑其决策连续性和属性可变性特征的实施机制这几个方面的问题。针对上述问题,给出了一个完整的职责模型,扩展了原有的UCON,并提出了一种通用的使用控制实施模型。     

Turbulent premixed flame model based on a recent dispersion model

A model of turbulent premixed combustion is formulated based on a recent dispersion model and on earlier flame models. The dispersion model accounts for the effect of velocity correlation on turbulent dispersion without using parameters that are explicitly dependent on time or space. The earlier flame models are used as a basis for formulating an appropriate chemical source term. The resulting model is more general than the earlier models.The proposed model and one of the earlier models are validated against various experimental flames. It is shown that the proposed model is more accurate and requires less calibration. Furthermore, the proposed model is tested successfully against general criteria for premixed combustion modeling formulated in earlier works. It is therefore concluded that the dispersion model is a useful tool for premixed combustion modeling.     

Stochastic gradient algorithm for a dual-rate Box-Jenkins model based on auxiliary model and FIR model

Based on the work in Ding and Ding(2008),we develop a modifed stochastic gradient(SG)parameter estimation algorithm for a dual-rate Box-Jenkins model by using an auxiliary model.We simplify the complex dual-rate Box-Jenkins model to two fnite impulse response(FIR)models,present an auxiliary model to estimate the missing outputs and the unknown noise variables,and compute all the unknown parameters of the system with colored noises.Simulation results indicate that the proposed method is efective.     

Staged model evolution and proactive quality guidance for model libraries

A variety of modeling approaches, including model-driven development, consider model reuse as one of their cornerstones, but lack support for model reuse. This may be due to the available model repositories that barely exceed support for enhanced versioning or collaborative work and disregard model evolution. We believe that current model evolution approaches do not consider reuse sufficiently and that model repositories for reuse purposes should act as model libraries. This requires new functionality, because models for reuse need to achieve and maintain high quality. Moreover, quality assessment and assurance, which are tasks often considered tedious, need to be as simple as putting away or maintaining artifacts for reuse. In this study, we propose an approach for model evolution in UML model libraries that differs from general model evolution, since it is aimless and triggered by new external requirements. Our approach is founded on graphs that are partitioned into three stages with respect to the level of reusability. Each stage is defined by quality characteristics that are manifestations of a quality model consisting of four essential quality dimensions: syntactic, semantic, pragmatic, and emotional. In order to achieve the next level of reusability, i.e., change the stage of a model, a quality gate needs to be passed. This can be supported by a proactive approach that guides the modeler through the enhancement process and offers additional recommendations based on the level of reusability. Since guidance cannot be fully automated, we implement a review mechanism founded on the idea of the six thinking hats to help maintain focus on the main aspects of a review. Finally, our approach is enhanced to support the evolution of generations, i.e., a group of several model snapshots, to ease reusability.