Using a data-centric event-driven architecture approach in the integration of real-time systems at DTP2

Integration of heterogeneous and distributed systems is a challenging task, because they might be running on different platforms and written with different implementation languages by multiple organizations. Data-centricity and event-driven architecture (EDA) are concepts that help to implement versatile and well-scaling distributed systems.This paper focuses on the implementation of inter-subsystem communication in a prototype distributed remote handling control system developed at Divertor Test Platform 2 (DTP2). The control system consists of a variety of heterogeneous subsystems, including a client–server web application and hard real-time controllers. A standardized middleware solution (Data Distribution Services (DDS)) that supports a data-centric EDA approach is used to integrate the system.One of the greatest challenges in integrating a system with a data-centric EDA approach is in defining the global data space model. The selected middleware is currently only used for non-deterministic communication. For future application, we evaluated the performance of point-to-point communication with and without the presence of additional network load to ensure applicability to real-time systems. We found that, under certain limitations, the middleware can be used for soft real-time communication. Hard real-time use will require more validation with a more suitable environment.     

Kernel software for efficiently building, re-configuring, and distributing an open CNC controller

Several open control architectures have been proposed to enable the incorporation of new technologies into existing CNC controllers. However, complex interfaces and communications among heterogeneous hardware and software platforms have yet to be resolved to reduce development time and cost. We propose a piece of kernel software that facilitates the development, reconfiguration, and distribution of CNC controllers. Assuming that various CNC control functions can be implemented and represented as software modules, the kernel software, acting as middleware, provides bridges between the software modules and the CNC machine by using the process and resource models. A resource model is created for each software module in order to represent its interface specification. A process model is used to represent the invocation sequence of software modules for a particular task received from the operators or other controllers. Based on the implementation of a prototype system, initial results look quite promising. The successful development of the kernel software will reduce the time and cost incurred in the development or modification of an open CNC controller .     

利用软、硬件中间件实现荒废测试仪器的替换

提出通过植入软、硬件中间件的方法实现对现有测试系统中荒废仪器的替换.介绍了国外运用该方法实现对原测试系统进行改造的成功范例,如通过植入硬件中间件实现替换的Winsoft公司的WISE(WinsoftInstrumentSystemEmulator)技术;通过在主控制器中植入软件测试模块适配器的Systems&Electronics公司的STMA(SoftwareTestModuleAdapter)方法以及美军利用IVI(InterchangeableVirtualInstrument)技术对现有LMIS(LockheedMartinInformationSystem)测试系统的升级改造.     

基于Delphi的电子商务系统的结构的比较与研究

本文分析了利用Delphi开发电子商务系统的技术,重点分析和比较了两种基于Delphi技术的电子商务的结构.     

基于XML的数据库信息动态发布技术

随着网络信息的大量涌现和广泛应用,原来简单的信息发布技术已经不能满足必须的信息交流与共享,当前对网上信息的处理(如信息搜索)主要是针对HTMLWeb页文档,而并没有深入到数据库中。XML的出现似乎为上述问题的解决提供了转机。文章介绍了一种实现关系数据库和XML文档之间数据转换以及最终发布的集成方案,为信息交互、检索等应用提供了技术基础。     

基于P-S系统的MOM模型研究

提出了基于出版者-订阅者系统的面向消息的中间件模型,阐述了其运行机理、工作流程、数据格式、功能结构以及消息的具体传递过程,解决了相关的条件匹配、位置透明和容错能力等技术问题,并探讨了其多播一致性、传送优化性和安全防范性,从而彻底解除了消息发送方-接收方之间的耦合关系,并屏蔽了网络底层分布式环境的复杂性和异构性,简化了分布式应用程序的编程策略,使分布式应用程序能够有更好的可用性、灵活性和扩充性。     

An integrated architecture for the provision of health telematic services based on digital library technologies

monolithic information system to effectively serve the needs of an entire healthcare organizational structure. Thus, information and telecommunications systems must primarily provide the infrastructure to support the effective integration of distributed and heterogeneous components, ensuring overall integrity in terms of functional and information interworking. This approach i.e., the integration of heterogeneous autonomous distributed systems, to developing and managing regional healthcare networks ensures the transfer and integration of consistent information between healthcare facilities, without imposing constraints on the operation of individual clinical units. This paper presents the results of an ongoing effort for the design and implementation of an architecture based on digital library technologies, for the provision of user-oriented telematic services in a regional healthcare network. Specifically, it addresses issues related to the provision of user-oriented services, transparent to the needs of different user groups and the requirements of specific tasks, based on: a) meta-information for the creation of an information infrastructure for the regional healthcare network which is, effectively, a multimedia distributed digital library, b) intelligent informationretrieval strategies to selectively retrieve information from multimedia data, c) agent-based technologies for effective service delivery adapted to the current user needs and the task at hand, and d) middleware services that explicitly reveal not only the characteristics of the information sources, but also address the context of specific telematic services, through appropriate mediation mechanisms. Received: 10 April 1997 / Revised: 6 July 1997 / Accepted: 5 August 1997     

一种基于C/S模式的分布式数据库服务器系统模型

该文介绍了一种分布式数据库服务器的构成原理及工作模型,讨论了它的冗余关系、中间件结构、并发控制策略、实现机理及其性能分析等。     

基于中间件技术的远程实时监测系统

重点介绍了一种新型的基于中间件技术的分布式远程实时监测与诊断系统,提出了由数据采集层、中间件应用服务器层、数据发布层组成的多层分布式实时监测系统模型;并针对中间件服务器层所涉及的一些关键技术进行了论述。设计了能够可靠传输实时监测数据的应用层协议,应用该模型和方法开发的远程实时监测与诊断系统在石化企业得到实现与验证。     

数据访问中间件系统设计与实现

为了解决大型系统开发过程中数据访问的一致性、实时性以及数据透明性等问题,该文拓展了数据访问中间件的概念,重点介绍了一个能够适应分布式信息系统开发应用需要的数据访问中间件的设计方案以及软件实现技术。