分布式Web组件模型分析

着重分析了组件模型的规范和ＣＯＲＢＡ、ＤＣＯＭ两种工业标准的组件模型。并探讨了组件模型的体系结构和分布工计算等问题。     

基于CORBA组件技术的三层数据库访问

分析了ERP系统中常用的二层数据库访问题系统的不足,介绍了一种基于CORBA组件技术、用Java实现B／S三层数据库访问的方法,并用一个简单的例子说明了在业务逻辑怎样使用CORBA对象访问数据库并进行业务处理。     

基于ASP组件技术的WebGIS的研究与实现

万维网地理信息系统(WebGIS)是Internet技术与现代地理信息系统技术相结合的产物。该文在对WebGIS现状及其解决方案进行研究之后,提出了一种新的WebGIS解决方案—MAPGIS-IMS。该方案以国产GIS软件MAPGIS为平台,ASP组件技术为基础,利用ASP来实现界面的显示和交互,采用三层Client/Server体系结构。MAPGIS-IMS是继MAPGIS-Web之后,中地公司推出的新一代WebGIS产品,相比MAPGIS-Web更加完善与成熟。     

基于软构件的应用服务器框架及其组件管理器的研究

应用服务器技术和组件技术是近几年软件开发技术的主要方向之一。它对Ｗｅｂ环境下的复杂应用如电子商务应用在可靠性、可伸缩性等方面有着非常重要的影响。论文在探讨应用服务器技术以及组件技术的基础上,通过结合ＣＯＲＢＡ开放性、跨平台、跨语言的特性以及ＥＪＢ技术的企业事务逻辑,设计了一个可伸缩、健壮的应用服务器体系结构并实现了事务服务与组件管理器。     

CORBA组件模型

1.引言最近几年,分布对象计算中间件(如CORBA中间件)在全球迅速发展和推广。这主要得益于CORBA允许在异种编程语言、异种平台、异种硬件的环境中,使客户在不知道对象所在地的前提下,调用分布的操作或对象。传统的CORBA对象模型提供了一个标准中间件框架,定义了ORB软件总线,使客户能调用本地或远端对象上的操作。同时为了提供可重用的组件,OMG定义了一些公共的对象服务,例如命名、交易和事件通知服务等。所以,使用CORBA和它的对象服务,设计者可以集成大型复杂的分布式应用。但是在CORBA3.0出现以前,它也存在如下的一些不足:没有标准的方法来配置对象实现;对CORBA服务器缺少公有的编程习惯;较难扩展对象功能,只能靠继承而不能使用组合;没有大家公认的对象服务,没有标准的生命周期管理。由于存在诸多不足,使设计者基于CORBA中间件开发/维护大型分布式应用工作量极大。所以OMG在CORBA3.0规范中提出了CORBA组件模型(CCM)(OMG 1999b)来帮助人们摆脱上述困境。     

JavaBeans组件模型的分布式扩展机制

结合ＪａｖａＢｅａｎｓ技术和Ｊａｖａ ＲＭＩ技术提出了ＪａｖａＢｅａｎｓ组件模型的分布式扩展机制,并在此基础上实现了基于ＪａｖａＢｅａｎｓ的组件化分布式应用运行平台。     

基于CORBA技术的分布式WEB计算

网络技术的不断进步使得运行于因特网上的Web计算方式成为分布式计算的新的发展方向。但是由于困特网具有异构特性,所以实现透明地访问不同的软、硬件平台便成为Web计算方式中的重要课题。当前,通用对象请求代理体系(CORBA)的出现使得这一问题最终得以解决。文章在对 Web计算方式的特点、CORBA规范的对象架构进行详细讨论的基础上,给出了基于CORBA技术的Web计算的具体实现方法。     

事备性组件方法研究

本文着重讨论了在ＤＣＯＭ体系下使用ＵＤＡ数据访问方法构事务性组件的实现模型,体系结构,机制和事务管理等问题。     

分布式对象技术——CORBA和EJB组件模型的研究

本文主要介绍了CORBA和EJB两种组件模型的特点,以及两种基于组件模型标准的Web应用体系结构的比较,最后提出了新一代的组件模型SOAP。     

基于WEB的企业模型仿真技术探讨

文章首先讲述了企业模型及其仿真的重要性,然后探讨了ＷＥＢ上企业模型仿真涉及到的相关技术,最后给出了相应的实现方式和技术。     

UM-RTCOM: An analyzable component model for real-time distributed systems

Component-based development is a key technology in the development of software for modern real-time systems. However, standard component models and tools are not suitable for this type of system, since they do not explicitly address real time, memory or cost constraints. This paper presents a new predictable component model for real-time systems (UM-RTCOM) together with a set of tools to support it. The environment allows new components to be developed which can then be assembled to build complete applications, including hardware interaction. The model includes support for real-time analysis at the component and application level. The analysis is achieved by combining component meta-information in the form of an abstract behaviour model and a method to measure worst-case execution times in the final platform. Additionally, we propose an implementation model based on RT-CORBA where the developer uses the UM-RTCOM components and a set of tools to map these elements to elements of the desired platform. In order to apply our proposals, we have used the model and tools in real applications specifically in the context of nuclear power plant simulators.     

A distributed adaptable software architecture derived from a component model

Today, Information Systems (IS) are often distributed and heterogeneous. Thus, software systems become more and more complex and their evolution is difficult to manage. Our works deal with engineering of heterogeneous distributed systems based on reuse. Such systems need a distributed adaptable software architecture to be implemented. In this paper, we propose a Model Driven Architecture (MDA)-inspired approach for developing adaptable software. First, we briefly present the component paradigm in which we place our works. Then, we position our component model with regards to related works. In our component model, the interface of the component is described by the way of points of interaction. These points are used to manage different types of interactions between components. The components and the interactions make up a new core model. From our core model, we can build an application model represented by a graph of interactions allowing the integration of the reused components. We finish with the implementation of the application model, thanks to the distributed adaptable software architecture. Each part of this paper is illustrated with a concrete case, the European Aero user-friendly SIMulation-based dIstance Learning (ASIMIL) project.     

The emergence of distributed component platforms

Several vendors and consortia have independently developed standards that define the basic mechanics for building and interconnecting software components. Sun's JavaBeans has emerged as the leading rival to Microsoft's DCOM, supplanting the OpenDoc standard from the now defunct Component Integration Laboratories. Component software is moving from its original focus on desktop-bound compound documents to enterprise applications that include distributed server components. The backers of competing standards are racing to capture market leadership by delivering the tangible benefits of component standards via distributed component platforms-integrated development and runtime environments that isolate much of the conceptual and technical complexity involved in building component-based applications. With DCPs, businesses can assign their few highly skilled programmers to component construction and use less sophisticated developers to carry out the simpler assembly tasks. By making component standards available to the broadest possible spectrum of developers, DCPs essentially drive those standards to market. This article reviews the state of component software as embodied in DCPs. The two DCP market leaders are Microsoft's DCOM (or ActiveX/DCOM) and Sun's JavaBeans. However, Internet and OMG component standards are emerging that will likely impact both the content and status of these two DCPs. The article also discusses component frameworks, which extend DCPs to provide more complete application development solutions     

Developing a distributed scalable Java component server

We present here approaches for a distributed scalable Java component server. The first one uses a resource broker model, whereby the system is composed of one or several entry point servers, a resource broker and a set of participating servers. The resource broker gives the system its dynamic scalability and load balancing capability by notifying participants and providing information to the entry point servers. An experimental version of the server has been developed. Two other approaches based on Jini and JavaSpace are proposed. An experimental version of the latter one is also compared with the resource broker model.     

基于SOAP的分布式构件集成研究

分布式构件技术提高了软件开发的效率，但各个构件的异构性也给应用软件的互操作性、兼容性以及平滑升级能力带来了问题，针对目前几种主要构件标准存在的缺陷，结合SOAP技术的发展，提出了一种基于SOAP的分布式异构构件集成模型，利用该技术能够灵活、透明、简便地集成各种分布式异构构件，实现异构构件自觉爱女的互操作。同时详细介绍了实现该模型的关键技术。     

构件技术在分布式信息系统中的应用

详细论述构件设计的思想,探讨一种基于构件技术的分布式信息系统开发方法,给出开发模型和具体的开发步骤．设计实现消防文书管理子系统,表明利用构件技术开发分布式信息系统是高质、高效的．     

基于EJB组件的分布式应用开发

Enterprise JavaBeans（EJB）是Java服务器端组件模型.首先分析了EJB的体系结构,介绍了EJB的各个组成部分,然后比较了EJB的种类和各自的技术特点,最后讨论了开发EJB组件的过程,并通过一个例子来阐述EJB组件在分布式中的应用.     

支持构件迁移的分布式系统容错算法

随着分布式应用技术的发展,构件的静态性限制了分布式系统在运行期间适应其可用资源变化的要求.为了动态适应系统可用资源,提高系统性能,支持构件可迁移的分布式应用研究受到广泛关注.针对提高构件可迁移分布式应用的可靠性,提出一种分布式系统容错算法.在准同步检查点算法的基础上,通过引入shadow-chain和通讯录机制,实现了构件间通信的可靠性和构件重定位的透明性,从而使得系统能够在较低代价下设置检查点,并能将出错后的系统回卷到一致性状态.     

基于LAMP的WEB安全模型

从Linux平台安全、Apache安全、MySQL数据库安全及PHP开发技术等几个方面探讨了如何架设一个安全高效的WEB网站技术,并给出了一个可行的安全模型。     

Exploring distributed control with the NK model

ABSTRACT

The NK model has been used widely to explore aspects of natural evolution and complex systems. This paper introduces a modified form of the NK model for exploring distributed control in complex systems such as organisations, social networks, collective robotics, etc. Initial results show how varying the size and underlying functional structure of a given system affects the performance of different distributed control structures and decision making, including within dynamically formed structures and those with differing numbers of control nodes.