分布式系统

Distributed interactive simulation technology has developed for decades andapplied to diverse industries. It is now enhanced with the development of computerhardware and network technology, and also modeling technology, virtual realitytechnology, software technology, and so on. On the other hand, people are bringingforward more and more requirements on distributed interactive simulation applications.Supports of distributed simulation systems are required on applications that involves inmassive complex simulation environment and large quantity of simulation nodes andentity objects, such as military simulation, online games. These requirements ask forhigh scalability of simulation support platform.

随着计算机硬件和网络性能的显著提高，现代建模技术、虚拟现实技术和软件技术等技术的发展，给已经发展了几十年的、深入各行各业的分布式交互仿真注入了新的内容和活力；而在另一方面，随着社会的进步，人们对分布式交互仿真的需求也越来越广泛，要求也越来越高，特别是在军事仿真、网络游戏等领域涉及到大规模仿真环境和大量仿真节点及实体的应用，需要分布式交互仿真系统的支持，这就对仿真支撑平台的可扩性提出了较高的要求。

Query of distributed database is to provide an interface between user and database, which is key technique in this field.

分布式查询处理是用户和分布式数据库的接口，是分布式数据库系统的主要问题之一。

Further more, the thesis lucubrates some key techniques: aiming at the management of the distributed objects, we skillfully construct the isomorphic project object tree for the real projects structure by using the CORBA naming service, and laconically and effectively implement the management of the services and modules by using the location service. And we also propose a design which uses CORBA event service and Borland MIDAS to implement the distributed data service in a creative way and analyze the advantages and disadvantages of this design at the same time.

并针对一些关键技术做了深入的讨论和分析，例如针对整个系统的分布式对象的管理，巧妙地借用CORBA的名字服务构造了同构于实际工程组织的工程对象树，同时使用定位服务简洁而有效的实现了对服务和模块的管理；针对分布式数据库的实现，创造性地提出了一种使用CORBA事件服务和Borland MIDAS组件来实现分布式数据服务的设计，并实现了这个设计，同时分析了这种设计的优劣。

It proposes some feasible schemes to build up the distributed geographic information system, and adopts the concrete implement technology to probe and attempt to develop the advanced distributed GIS in order to supply some refers to man-sized distributed GIS research and the building on computer network environment.

为分布式地理信息系统提出了一些可行的方案，并使用具体的实现技术为研制新的分布式GIS进行了探索和尝试，为今后在网络环境下大型分布式GIS的研究和建设提供一些参考意见。

More and more practical data in sensor network、communication、Internet flow analysis and Web log etc, are transported from teledata sources. Therefore, we need to construct the middleware of distributed query processing for data streams to support above application.P2P technique is used to build a huge distributed network for the processing of large number of information by internet terminals.

现有的数据流的研究主要为集中式的流数据系统，而数据流的本质是分布式的，越来越多如传感器网络、数据通讯、Internet流量分析和Web日志等的大量数据都来自不同的远程数据源，因此，需要构建分布式数据流查询处理的中间件以支持上述各种应用。P2P技术利用互联网的终端机来建立一个庞大的分布式计算网络，并对迅速涌出的大量信息进行处理。

In electronic payment system, it is more suitable to introduce the distributed electronic bank scheme in networks environment. However, in current scheme, the users obtain their cards issued by the bank in which they have opened their accounts and withdraw and store their e-coin at the bank. Due to limits of current network neckbottle and security, dispersed and mobile users in different areas, there are some defects in a practical monadic account e-bank scheme.

摘要在电子支付系统中，采用分布式电子银行方案更适合于网络运行环境，然而在现行的分布式电子银行方案中，每个用户局限在所开帐户的电子银行取得签发的Smart Card和提取或存储电子货币，由于网络的瓶颈作用和安全缺陷，以及用户所处地域的分散性和流动性等因素的限制、使得单一开户的银行方案在实际应用中其分布式特性并未充分得以发挥。

Secondly, most of typical scheme for MANET multicast reking are based inbalanceable key tree, the most import problem of multicast reking is providingforward security when member leaves and backward security when member join, then,how to improve efficient of multicast reking, decrease the cost of reking, is the coreproblem of balanceable key tree for MANET multicast reking.

对于大规模自组织网络，采用完全集中式或完全分布式的组****管理的方式容易形成系统单一失效点、产生网络分割、不同步等问题，实际应用中宜采用结合集中式和分布式优点的分散式的组****管理框架，子组中心管理和用户子组管理是框架的两个管理层次，对子组中心管理关注的是组****分发的安全性和效率，如何实现分布式身份可验证的组****分发是自组织网络组****管理的关键问题。

Web contenting and Web structure mining are becoming the core of third generation search engine, and improves information retrieval on the Web to a high quality and intelligent level.

在完成Web挖掘理论研究的基础上，我们实现了一个基于Web挖掘算法的分布式信息检索平台LUKA，它包括了分布式Web文档收集、Web挖掘算法、分布式Web链接分析算法、半结构化文档概念索引等多个模块，它们有机的组成了一个Web信息挖掘的原型系统。

The dynamical characteristics of a low voltage MicroGrid from grid-connected mode to islanded mode with different distributed generation configuration schemes are analyzed by using simulation method,and the corresponding changing laws of each DG's power,voltage and frequency of MicroGrid are obtained.

通过算例仿真研究了不同分布式电源配置方案下低压微网从并网模式向孤网模式转换的动态运行特性，获得了分布式电源的功率、微网电压和频率的变化规律。如果选择微型燃气轮机作为微网的功率支撑手段，在微网从并网向孤网过渡过程中，系统频率波动较大，且部分分布式电源有可能在低频保护动作下与电网隔离，不利于微网的稳定运行；增加储能设备后，储能设备对于微网的稳定运行可发挥重要的作用。

A lot of experiments show thatthe above algorithm is correct and control system structre based onjoint variables is feasible, offering a foundation for more accuratepositioning of double-triangle-boom.5. Analyses the control system components of rock-drilling robot.Designs an independent CAN-bus distributed control system for eachboom to avoid disadvantages of centralized control.

分析了凿岩机器人控制系统的构成及信号关系，指出了集中控制方式带来的问题，提出了基于CAN总线的凿岩机器人分布式控制系统结构，对一个臂按模块功能在总线上设计了操作台、传感器、执行器和控制器四类CAN总线智能节点，形成一个相对独立的分布式控制系统。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。