基于Agent的离散事件仿真系统的控制功能框架研究

在研究基于Agent的离散事件仿真技术的基础上,提出了一个基于Agent的离散事件仿真系统的控制功能框架(ADESCF)。该框架包括了输入接口控制、输出接口控制、模型结构控制、仿真时钟控制、实验数据控制、仿真实验控制、仿真逻辑控制七个功能元素。分析了各种控制功能的工作原理与机制,并从输入输出连接关系角度分析了多Agent仿真系统层次化与分布式建模的本质,为该类仿真系统的开发提供了可参考的依据。     

对象关系转换接口在飞行仿真建模环境的应用研究

飞行仿真建模环境是构造飞机飞行仿真模型并进行飞行仿真实验的软件平台.作为一项复杂的大系统,FSME采用了当今流行的面向对象建模工具--统一建模语言UML对系统进行建模,因此在FSME系统的前台飞行仿真模型是以对象的形式存在.由于当今数据库市场上面向对象数据库产品还很少,因此存储飞行仿真模型的模型库采用了当今主流的关系型数据库库管理系统.因此仿真前台对象和后台存储的关系表格之间存在着"阻抗不匹配"的问题.该文主要阐述对象关系转换接口的设计、实现及在飞行仿真建模环境中的应用.     

应用框架法的化工过程系统通用模型

企业领域的面向对象应用框架研究是现代面向对象应用框架技术的重要趋势之一.应用框架可以增强大型应用软件代码的重用性和可扩充性.针对目前化工过程系统软件中存在的问题,采用面向对象应用框架方法,建立起化工过程系统的通用模型.结合使用本模型完成的国家教委项目--化工仿真系统来阐述该模型.     

基于模型的空面导弹仿真系统设计

采用基于模型的仿真软件设计思想,研究了空面导弹的飞行仿真系统的设计方法,针对具体的任务和功能要求,建立了仿真系统多层次的结构体系.应用软件工程中面向对象的方法和模块化设计的建模理论,对仿真系统的仿真模型设计进行了研究,确立了模型的描述形式和接口设计规范.仿真系统遵循模型与数据相分离、数据交换通过接口实现的设计原则,采用消息驱动机制管理整个仿真过程,已成功应用于某型空面导弹的仿真试验中.     

基于面向对象技术的航空发动机性能仿真框架设计

根据航空发动机性能仿真的需要,采用面向对象技术和分层设计思想,构造了航空发动机性能的通用仿真系统框架.该框架中,利用面向对象技术形成了模型对象类属层次关系,并由下向上逐层完善,提高了仿真框架的适应性和可扩展性.利用该仿真系统框架,建立了某单轴涡喷发动机仿真对象模型,通过对其进行静动态特性仿真,验证了该框架的有效性.     

基于COM的HLA中间件框架

HLA(高层体系结构)作为DDD(美国国防部)制定的分布交互式仿真标准,从很大程度上提高了仿真模型的可重用性和互操作性。为了重用大量原有的面向过程的仿真系统和模型,HLA采用了一组面向过程的API。这又使得基于HLA的仿真开发变得困难(相对于面向对象来说),同时,其对开发人员的技术要求较高,培训时间较长,费用昂贵。这极大的妨碍了基于HLA的分布交互式仿真开发的普及和发展。该文将探讨一个旨在简化基于HLA仿真开发接口的中间件框架,利用当今比较流行的COM技术,与HLA标准结合起来。以COM组件的形式对HLA接口进行封装,在保留HLA标准所带来的良好互操作性和可重用性的同时。以COM接口的形式向仿真开发人员提供简单易用的,面向对象的接口,从而降低基于HLA的分布交互式仿真系统开发的复杂度。     

一个基于方程的混合系统仿真应用框架

为了便于混合系统的建模与仿真,提出了一个可以用通用开发平台实现的框架:敏捷仿真应用框架(AAFS).AAFS基于方程建模,消除了模型的因果性,提高了模型的复用性;提取了构成仿真的模型、问题和数值求解器三个抽象,降低了AAFS内部各组成部分的耦合性;使用模型间的关联和连接器组合模型、搭建系统,使构成系统的慨念和方程可以被层次化的管理:用UML符号给出了AAFS的设计,说明了AAFS易于被当前面向对象的编程语言实现;定义了模型与求解器的接口,增加了对数值解法的选择性;给出了一个用AAFS实现的弹簧、质子系统的建模仿真例子,说明了AAFS的使用方法及其带给使用者的便利性.     

敏捷制造环境下基于面向对象的柔性裁剪仿真建模研究

为提高敏捷制造系统仿真建模的效率和效益。在讨论国内外有关系统建模理论的基础上,提出了敏捷制造环境下基于面向对象的柔性裁剪仿真建模的概念。然后,对基于面向对象的柔性裁剪仿真建模的形式化进行了研究。提出了一个敏捷制造环境下基于面向对象的柔性裁剪仿真建模框架,最后,以Arena集成仿真环境为例,提出了敏捷制造环境下基于面向对象的柔性裁剪仿真建模的一般步骤。     

通用电子战M&S支撑环境设计与实现

随着大规模先进分布仿真技术的兴起和现代仿真技术领域的不断拓展,仿真的规模和复杂性与日俱增.传统的面向过程的建模与仿真,由于不同对象和过程之间的相互耦合,已远远无法满足像电子战这种实体众多、关系错综复杂的大型系统仿真的需求.联合建模与仿真环境(JMASE)基于面向对象理论和技术,通过定义一系列标准、服务和模型接口及提供一组工具集,实现了模型开发、测试与分析过程的一体化和标准化,促进了不同领域仿真模型的互操作和可重用,有效地解决了复杂大系统M&S所面临的困难,为用户提供了一个开放的、面向对象的通用电子战M&S支撑环境.     

面向对象仿真的基本概念框架研究

在分析了面向对象技术和仿真技术的基础上,提出了面向对象仿真的基本概念框架,并给出了这一基本概念框架的内涵。通过对仿真基本概念、仿真三要素、面向对象建模、面向对象仿真基本概念和系统发展需求等方面的深入分析,证明文中提出的面向对象仿真的基本概念框架是面向对象仿真的客观反映。     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。