多维关注分离的模型驱动过程框架设计方法

当前,许多模型驱动软件项目过程采用多种开发方式相结合的形式.但开发方式的比较、选择、组合操作却缺少系统化的方法指导.提出一种多维关注分离的开发过程框架设计方法.采用一般化、行为化和抽象化作为元关注维,对开发方式进行比较.结合这三维的期望演化曲线,给出过程实现模型框架.对于模型驱动开发过程的提高开发效率、增强可跟踪性和保证一致性等非功能性需求有一定的参考意义.     

一个决策驱动的网构软件动态演化模型

传统的建模方法比较难实现网构软件系统的动态演化和自适应性,基于决策驱动的网构软件动态建模方法研究已经成为一个热点。从决策抽象和问题分解角度,提出一个决策驱动的网构软件动态演化模型。首先使用松弛原子算法来分解问题与动态组合决策;然后采用累加累减算法建立网构软件动态演化模型;最后设计相关的网构软件系统来验证该模型。性能分析表明,相比传统模型,该模型有良好的动态演化效果。     

修正局部极小值的局部灰度差异分割模型

针对现有局部模型在分割灰度不均匀图像时容易陷入局部极小值,导致演化曲线停留在背景处或目标内部无法继续演化从而造成分割失败的现象,提出本模型。该模型在能量泛函中增加局部灰度差异项,通过最大化演化曲线上所有点的邻域内目标和背景的差异来驱动演化曲线越过图像背景处或目标内部,直到准确地停留在目标边缘。实验结果表明提出的模型可以有效地解决局部模型因陷入局部极小值而导致的误分割问题,同时提高对分割灰度不均匀等复杂图像的准确性,并减小对初始轮廓的敏感性。     

基于遗传规划的行为模型精化方法

行为模型的精化是软件工程中的基于模型驱动开发的关键问题.基于针对环境的形式化行为模型和形式化方法中的精化理论,提出了一种基于遗传规划的行为模型的自动精化方法.该方法将精化看作可执行的基本操作的组合过程.首先通过分析抽象行为的后置条件公式,执行基于逻辑归约的精化方法,从而生成循环结构和其他简单新行为的描述.然后利用基于遗传规划的精化方法对新行为继续精化,直到产生的程序最终由基本操作构成.由于传统的遗传规划方法对选择结构难以演化,提出了组合终止条件的概念.通过测试组合终止条件,选择结构也能较好的产生.最后以排序问题为例,给出实际的演化过程,结果说明该方法具有较强的可行性.事实上该方法适用于任何由若干基本操作组合以完成复杂操作的问题求解过程.     

模型驱动构架中基于元模型的设计模式单元的组建和转换

设计模式种类繁多而且在不断变化,要在模型驱动构架（MDA）下真正做到从思想和实现上均能应用设计模式,需要解决其实例化后的模式消失问题,保证模式的独立性,并且可以将这个过程适用到多种设计模式中去。针对以上两个问题,采取一种基于元模型的设计模式单元的建模方法,从元模型层面划分基本操作为不可分的原子,组合出完整的不包含业务逻辑部分的设计模式单元元模型,使多种模式单元元模型的组合构建和业务、模式逻辑相分离在经过一次转换过程后同时实现。     

一种基于Petri网的分布组件协调模型

协调是分布组件系统中的基本问题之一.但是,协调问题至今仍未得到很好的解决.根据实际应用的要求,提出了Concerto协调模型.它以Petri网为数学理论基础,扩充了Petri网的语义,引入了控制缓存和数据缓存,分别反映了分布组件的控制依赖和数据依赖关系,统一了现有的控制驱动和数据驱动两类协调模型.对于Concerto模型的运行,提出了驱动模式、动作规则和Concerto引擎.驱动模式有4种:依赖操作时间的驱动、依赖最小时间的驱动、依赖最大时间的驱动和依赖平均时间的驱动.这些驱动模式在实时系统、流量控制和任     

示教机器人模型

这个模型具备示教再现机器人。的基本构成:传感器、示教键盘、控制器、驱动电路和电机伺服系统。虽然只有两个自由度,但经过不同机械结构的组合,以及通过示教,可做出很多有趣的动作,它还可以成为机械昆虫的一条腿。     

模型驱动开发中模型演化语法和语义特性研究

模型演化由一系列复杂的变化活动组成,要遵循一定的约束以保持模型的某些特性。以一个实例描述模型演化的过程,并以集值映射为基础,定义模型成分与语义域的映射,通过定义模型演化的语义函数,研究模型演化的语法和语义性质,包括特性保持、一致性、等价性和吸收性等。     

模型驱动的Web服务组合的QoS属性的研究

为反映组合Web服务的服务质量(QoS),文章在用模型驱动的方法对Web服务组合进行研究的基础上探讨了如何对Web服务进行QoS属性拓展,给出了拓展的WSDL元模型。通过引入模型驱动的思想,解决了Web服务对QoS属性描述不足的问题。并通过对BPEL元模型的分析,得出了组合服务在各种结构模型情况下的QoS属性的计算方法。     

基于极限学习机的组合软件可靠性模型研究

针对单一软件可靠性模型适应性不强和数据驱动模型稳定性较差的问题,本文选取3种典型软件可靠性模型作为基模型,利用极限学习机对基模型的预测结果进行加权优化,得到组合软件可靠性模型,实现经典软件可靠性模型和人工智能算法的有机结合。通过对3组失效数据进行仿真实验,并与单一模型、基于其他神经网络算法的组合模型以及数据驱动模型的预测结果进行对比,验证了本文模型能够有效地提升预测精度和模型的适应性。     

Model integration using SML

Structured modeling language (SML) is a modeling language for the structured modeling framework, which represents the semantics as well as mathematical structure of a model. This paper extends some structured modeling concepts and defines SML schema operations for formalizing model integration. Executing any of the operations could possibly disrupt the integrity of an SML model schema. Some major propositions and several examples in the paper settle practically many of the open questions for the operations studied. This research not only contributes an operational approach to perform model integration in SML, but also allows us to understand how different kinds of schema edits can disrupt the formal correctness of SML, and what can be done about it. It helps lay the foundation for the future development of an incremental static semantic analyzer and smart schema-directed editor.     

分布式电子商务服务供应链建立过程的原语描述

电子商务服务的分布式模型中,服务供应链的建立过程可使用多种算法,针对广度优先算法,该文设计了一套形式化的过程原语对其进行捕述,完整表达出整个服务供应链的建立过程。该文定义的过程原语适用于在同一个分布式模型中多个服务请求者同时对同一服务发起的服务供应链,最后用Petri网对具体模型中服务供应链的建立过程进行建模。     

Open Inventor在STK模型转换中的应用

为解决航天仿真系统中的航天器建模问题,对STK模型文件进行了结构分析,探讨了STK建模语言和VRML建模语言在总体规则、语法语义等各方面的异同,构建了读取STK模型文件、调整其数据结构、利用Open Inventor重构模型、最终输出标准的VRML模型文件的框架,集中讨论了引用图元、模型动作、模型纹理、模型变换的转换方法,并据此开发了一套模型转换程序.实践证明,该方法能够实现STK模型图元、参数、变换和动作的转换,与以往方法相比,能够大大降低运算复杂度和存储消耗.     

Consistency maintenance for evolving feature models

Software product line (SPL) techniques handle the construction of customized systems. One of the most common representations of the decisions a customer can make in SPLs is feature models (FMs). An FM represents the relationships among common and variable features in an SPL. Features are a representation of the characteristics in a system that are relevant to customers.FMs are subject to change since the set of features and their relationships can change along an SPL lifecycle. Due to this evolution, the consistency of FMs may be compromised. There exist some approaches to detect and explain inconsistencies in FMs, however this process can take a long time for large FMs.In this paper we present a complementary approach to dealing with inconsistencies in FM evolution scenarios that improves the performance for existing approaches reducing the impact of change to the smallest part of an FM that changes. To achieve our goal, we formalize FMs from an ontological perspective and define constraints that must be satisfied in FMs to be consistent. We define a set of primitive operations that modify FMs and which are responsible for the FM evolution, analyzing their impact on the FM consistency. We propose a set of predefined strategies to keep the consistency for error-prone operations.As a proof-of-concept we present the results of our experiments, where we check for the effectiveness and efficiency of our approach in FMs with thousands of features. Although our approach is limited by the kinds of consistency constraints and the primitive operations we define, the experiments present a significant improvement in performance results in those cases where they are applicable.     

基于消息的构件组合运算与构件演化

根据构件能够接收和发送的消息，扩展了构件接口定义框架，给出了基于消息的构件组合模型，定义了构件的执行路径，对四种组合运算进行了形式化描述，提出并证明了六则构件演化运算．给出了一个实例：把一个没有显示语义的层次系统模型简化为语义明确的树形组合模型，并给出了模型的代数表达式和简化算法．     

峰度驱动的云进化策略

为了从传统进化策略的角度分析并改进云进化策略,研究云分布的峰度统计量及其应用。云分布在固定标准差时,也可通过调整峰度来改变噪声形状,可能产生更有效的变异。推导云分布峰度计算公式,以支持熵-超熵空间和标准差-峰度空间的相互转换。比较峰度和峰比对云分布噪声的影响,证明峰度更适宜自适应演化。给出峰度驱动的云进化策略,它的参数演化结合基于1/5规则的标准差演化和自适应峰度演化。对8个测试函数的实验结果显示,高峰度利于全局寻优,低峰度利于局部寻优,而峰度的自适应调整可综合二者优势。     

基于时间序列模型的黄金价格预测

由于黄金价格受到诸多经济及政治因素的影响,其生成过程十分复杂,因此研究黄金价格的动态演变过程具有极强的现实意义。而具体的预测要根据市场的过去和当前的需求,以及影响市场需求变化的因素之间的关系,利用一定的判断、技术和模型,对其价格波动变化及发展趋势进行分析和判断。利用时间序列相关理论,建立黄金价格的ARMA模型,发现其可以动态刻画黄金价格数据的生成过程并且较好地对黄金价格进行预测。     

Model evolution and refinement

Software changes during its lifetime. Likewise, software models change during their design time, e.g. by removing, adding or changing operations and classes. This is referred to as model evolution. In a refinement-based approach to software design, we moreover do not deal with a single but with a chain of models (viz. formal specifications), related via refinement. Changes thus need to be consistently made to all specifications in the chain so as to keep the refinement structure.In this paper, we develop co-evolutions of models in the context of the formal method Object-Z. More specifically, given a particular evolution of a specification we show how to construct a corresponding evolution for its refinements such that the refinement relationship is kept. A chain of models can thus be systematically and consistently evolved, while maintaining the given refinement structure.     

A framework for 3D model reconstruction in reverse engineering

We present a framework for 3D model reconstruction, which has potential applications to a spectrum of engineering problems with impacts on rapid design and prototyping, shape analysis, and virtual reality. The framework, composed of four main components, provides a systematic solution to reconstruct geometric model from the surface mesh of an existing object. First, the input mesh is pre-processed to filter out noise. Second, the mesh is partitioned into segments to obtain individual geometric feature patches. Then, two integrated solutions, namely solid feature based strategy and surface feature based strategy, are exploited to reconstruct primitive features from the segmented feature patches. Finally, the modeling operations, such as solid boolean and surface trimming operations, are performed to “assemble” the primitive features into the final model. The concepts of “feature”, “constraint” and “modeling history” are introduced into the entire reconstruction process so that the design intents are retrieved and exhibited in the final model with geometrical accuracy, topological consistency and flexible editability. A variety of industrial parts have been tested to illustrate the effectiveness and robustness of our framework.