A prototype for spatial information services based on J2EE

J2EE (Java 2 Platform , Enterprise Edition) is a kind of architecture that simplifies the development ,design and management of multilevel enterprise solution. The spatial middlewares based on J2EE can easily resolve the problems which the traditional Geographic Information Systems (GIS) now have to face wit,such as transplantability,stability, easy maintainability and many more. This paper first introduces some conceptions and principles about J2EE,spatial middleware. then proposes a concrete J2EE-based solution of spatial middleware,namely SISP AS,which develops on JBoss(an open sources application server of J2EE) and uses the SISP spatial database. SISP AS follows Open GIS specifications,and implements a subset of OGC services. it improves interrperability and commonality by using XML/GML for communication and data transmission,resolves the transmission efficiency problem of large spatial data by using raster pyramid and vector pyramid. Finally,the related work will be presented. Notably, the experiments on this prototype system can proves that it is available to manage,distribute and share large scale spatial data by using SISP AS.     

Two-Level Cross-Talked Admission Control Mechanism for QoS Guarantee in 802.11e EDCA

This paper describes a two-level cross-talked admission control mechanism that guarantees quality of service （QoS） requirements for multimedia applications over wireless local area networks （WLANs）. An enhanced distributed channel access analytical model is used to compute the maximum number of admitted users according to the QoS requirements and the packet arrival characters. Then, some channel resources are reserved for handoff calls based on the maximum number of admitted users and the call-level traffic model. The channel utilization ratio is also measured to reflect the current system traffic load. The maximum number of admitted users and the channel utilization ratio are used for admission control for applications with QoS requirements in the call level and for rate control of best effort applications in the packet level using the p-nonacknowledgement scheme. Thus, the QoS requirements are statistically guaranteed while the system is efficiently utilized. Simulations validate the effectiveness of this mechanism to guarantee the QoS and bandwidth utilization.     

基于CFP的分布式数据采集应用

传统的工业自动化控制使用PC和PLC来完成,但PLC的功能又满足不了需要。文章介绍了一种能同时提供PC和PLC功能的产品,NationalInstruments(NI)分布式I/O产品-CompactFieldPoint(CFP),并提出了一种基于CFP的分布式的数据采集方案。该方案具有实用性强,便于开发且容易扩展的特点。     

一类分布参数问题的鲁棒稳定性

在文献[1],[3]的基础上,应用李雅普洛夫方法,从时滞非线性问题的稳定性出发,研究其零解大范围渐近稳定的充分条件;进而研究时滞非线性分布参数问题的鲁棒稳定性,最后给出其零解鲁棒稳定的充分条件和有关证明。     

基于局部检测统计量的反馈多传感器分布式检测

传统的多传感器分布式检测反馈方法把融合中心的二元判决送到局部检测器,再利用局部检测器的二元判决形成下一次融合,从而需要双向通信.为了更充分的利用观测信息,降低系统的复杂度,该文提出了一种基于局部检测统计量的多传感器分布式检测反馈方法.新的反馈方案把融合中心的全局统计量重新送到融合中心,与下一步的局部检测统计量一起形成新的全局统计量.并在局部检测器为两个的情况下,分析了新的反馈方案的检测性能并与传统的方案进行了比较.结果表明新的方案使分布式检测性能有明显加强,同时更便于实现.最后给出了实际应用的计算分析方法.     

Manufacturing Communication： DCOM-MMS-based Approach for Flexible Manufacturing System

A design approach of manufacturing communication is presented for flexible manufacturing system in this paper. The primary objective aims at making the flexible manufacturing ,control system provided with interoperability and reconfigurability. Based on describing manufacturing message specification （MMS） and distributed component object model （DCOM）, a client/server manufacturing communication model is built with MMS standard and DCOM middleware, and the communication interfaces between MMS client and MMS server are designed with Microsoft interface definition language （MIDL） and abstract syntax notation one （ASN. 1） of MMS services. As a result, DCOM and MMS integration leads to such client/ server communication capabilities independent of different operating systems and manufacturing devices in flexible manufacturing automation environment. Finally, to verify the new design approach, a prototype system of robot control system has been implemented in MS 2000 Server/Professional Operating System and VC ＋ ＋ 6.0 Developer Environments.     

论数学教育学的对象,范围和方法

本文从数学教育学是一门多学科“交叉”性综合学科的学科性质出发,揭示了数学教育学的对象、内容、范围、对数学教育学的方法:历史分析法、特征归纳法、逻辑推演法、突现综合法、观察实验法和定量化方法等作了较为全面、系统的论述。     

基于分布式流的复杂网络上边级联失效

考虑现实网络中流的分布式传输方式和边的负载-容量关系,提出了一个带有可调权重参数的边级联失效模型.依据新的度量网络鲁棒性指标,探讨了两种典型复杂网络由蓄意边攻击而引发的级联失效行为.仿真结果表明,存在最优参数值使得网络达到最强抵制边级联失效的鲁棒性,能够显著降低灾害动力学发生的可能性.而且,网络的拓扑结构和平均度均对网络鲁棒性产生了影响。     

压电合成射流激励器LEM方法研究

基于线性复合平板理论,将机-电-声等效方法应用于压电合成射流激励器,建立了激励器的集总参数模型(LEM).借助ANSYS软件和Matlab软件提取等效模型的关键参数,并使用Matlab软件对合成射流激励器的LEM模型进行了仿真.仿真结果与实验测试值进行了对比,两者吻合得较好.与传统仿真方法相比,所提出的LEM方法具有操作简单、耗时短、占用资源少和效率高等优点.      

裂缝稠油油藏流体流动裂缝开度界限初步探索

裂缝稠油油藏中,裂缝储量易开发,基质储量难开发。然而,划分裂缝和基质的开度界限及基质中微裂缝可流动开度下限均难以确定。针对A裂缝稠油油藏,基于渗流理论和微观机理实验,初步探索得到原油"可动"开度绝对下限3μm左右、原油"可动"开度技术下限10μm左右、原油"易动"开度绝对下限5μm左右、原油"易动"开度技术下限15μm左右、水驱油"最佳"开度界限40~50μm等5个A裂缝稠油油藏开度界限。可动开度下限可指导计算有效储量,易动开度下限可指导划分裂缝基质储量,水驱最佳开度界限可指导井位部署。研究思路与方法,对同类油藏开发研究具备一定借鉴意义。