An Analytical Method for Predicting the Performance of Parallel Image Processing Operations

This paper presents an analytical performance prediction model and methodology that can be used to predict the execution time, speedup, scalability and similar performance metrics of a large set of image processing operations running on a p-processor parallel system. The model which requires only a few parameters obtainable on a minimal system can help in the systematic design, evaluation and performance tuning of parallel image processing systems. Using the model one can reason about the performance of a parallel image processing system prior to implementation. The method can also support programmers in detecting critical parts of an implementation and system designers in predicting hardware performance and the effect of hardware parameter changes on performance. The execution of parallel image processing operations was studied and operations were arranged in three main problem classes based on data locality and the communication patterns of the algorithms. The core of the method is the derivation of the overhead function, as it is the overhead that determines the achievable speedup. The overheads were examined and modelled for each class. The use of the method is illustrated by four class-representative image processing algorithms: image-scalar addition, convolution, histogram calculation and the Fast Fourier Transform. The developed performance model has been validated on a 16-node parallel machine and it has been shown that the model is able to predict the parallel run-time and other performance metrics of parallel image processing operations accurately.     

多媒体视频会议系统的关键技术研究

多媒体视频会议系统是近年来国际上将“视频图像、语音等多媒体信息数字处理”与“数字通信传输技术”最新成果相结合的产物，它集计算机的交互性、通信的分布性以及电视的真实性为一体，具有明显的优越性，因而成为当今计算机领域的一个研究热点。本文主要讨论了该系统的组成、原理及关键技术，尤其是图像压缩技术的研究。     

盐湖卤水动态自动观测系统

介绍了盐湖卤水动态自动观测系统的体系结构，以及系统硬件、软件的设计方法和关键技术。该系统采用了主从分布式结构，是一个典型的遥控遥测系统。     

企业网络系统中的现场总线技术

本文介绍了以现场总线为基础的企业信息网络集成系统。描述了企业信息网络集成系统的层次与结构；作为其基层网络的现场总线系统的结构特点、技术特点与优点，以及几种有影响的现场总线技术。     

DCS在兰化化纤厂的应用

兰化化纤厂采用硫酸氰钠一步法的工艺生产流程，采用μＸＬＤＣＳ系统作为主控系统，控制系统主要包括聚合工序、纺丝工序、溶剂回收工序、萃取工序。本文主要对兰化化纤厂μＸＬ系统组态、数据通信和信息集成为主要对象进行论述。     

Development of a collaborative CAD/CAM system

This paper presents the development of a collaborative CAD/CAM system (COCADCAM). COCADCAM extends an existing single-location CAD/CAM system to a multi-location CAD/CAM application so that two geographically dispersed CAD/CAM users can work together on a three-dimensional CAD-geometry coediting and CAD-related tasks collaboratively and dynamically. COCADCAM dynamically supports CAD data communication that are not available in traditional single-location CAD/CAM. The dynamic data communication is achieved through the development of networking algorithms and CAD/CAM functions in this paper. The networking algorithms based on UNIX Interprocess Communication (IPC), the Network File System (NFS), and a connection-oriented client and server model under the Transmission Control Protocol/Internet Protocol (TCP/IP) suite. The CAD/CAM functions included surface modelling, simulation of a milling toolpath, and post-processing of an NC program following collaborative CAD-geometry coediting, which are directly or indirectly supported by the Application Programming Interface (API) of the CAD/CAM software. The networking algorithms and CAD/CAM functions together can facilitate an environment for CAD-geometry coediting and related tasks such as design, analysis and manufacture. COCADCAM has been successfully implemented through local area network (LAN) and the Internet; a remote machining cell is also linked so that the generated NC program based on a coedited free-form surface can be used for the physical machining operation. The algorithm proposed by COCADCAM can be referenced for the extension of other single-location CAD/CAM systems to multi-location applications.     

基于CAN总线的分布式控制网络设计

采用CAN总线构建多主站的分布式控制网络,设计了基于P87C591单片机的CAN总线控制器。结合分布式控制系统在机器人控制中的典型应用,设计了CAN应用层协议和相应的通信软件。将本控制网络应用于自主研发的水下机器人,成功完成了湖试检验。     

新型低压电动机综合保护装置原理与实现

从保护的原理,硬、软件的实现出发,介绍一种新型的低压电动机的保护装置。该装置具有功能齐全、性能可靠等特点,方便系统集成,能有效地提高低压电动机的保护水平。型式试验和现场运行结果证明了该保护原理和实现的有效性。     

智能型自动转换开关的通信接口设计

介绍利用PIC16F877微处理器实现智能型自动转换开关在DeviceNet与Modbus现场总线网络中通信的功能,主要包括实现通信的硬件接口及主要程序流程。     

过载保护继电器的智能化设计

在研究了过载保护继电器保护原理的基础上,以PIC16F877单片机为核心部件,从硬件、软件两方面对过载保护继电器进行了智能化设计。同时,考虑到过载保护继电器的工作环境,采用隔离、神经网络滤波等措施进行了抗干扰设计,从而能够可靠实现电动机故障的自动诊断、智能控制、保护及远程串行通信等功能。