过程网

This article elaborates the full-scale test at present electric railway bow net system, designs a new control system to fall the Pantograph fall and introduces a home unusual, controlled Pantograph fall in the busy host skeleton line. This research provides reference for the furthur study of bow net protection system by artificially creating the real appearance of bow net relations.

从实际试验出发，阐述了在目前电气化铁路弓网系统中，对弓网保护装置所起作用的一种验证方法，同时构思和设计了一种新型的受电弓滑板掉块控制系统，并介绍了一次国内少有的、在繁忙主干线上控制受电弓滑板掉块造成人为弓网关系再现的真实过程，为进一步开展弓网保护系统研究提供参考。

Based on the two features of the Delaunay triangulation:maximum and minimum feature,empty circumcircle feature,in this article the procedure of building triangulation network needs three steps:creating boundary,building up the interior triangulation network,coping with the hole between the boundary and the interior triangulation network.

基于Delaunay三角网划分的两个特性：最大最小特性与空外接圆特性，论文构网过程分三步：生成边界，构造内三角网，对边界与内三角网之间的空洞进行处理。

A numerical method is gived to distinguish that a Petri net is a time charac-teristic nets or not.The time characteristics of transmit are discussed and the density formula of transmit is given. stochastic petri nets ; time characteristic ; distractive matte

一般情况下，随机Petri网现有的分析方法大多是假定变迁的发射时间服从负指数分布，然后将网标识过程等价于连续参数马尔可夫过程，然后利用求解马尔可夫过程的一套数学方法来分析Petri网的时间特

Firstly, according to the modified workflow process meta-model, a P/T system based workflow model procedure net is proposed.

首先，根据改进的工作流过程元模型，研究并提出了一种基于P/T系统的工作流过程模型过程网。

Primarily, the thesis assays the condition of network framework, the network was divided into three levels in terms of network management in order to establish the distributed method ,and still pointing out the intention and denotation of studying the Topology Discovery.Next, the thesis analyzes SNMP protocol minutely, including its development, principle, and the Network Management system that established on the SNMP protocol. Have analysed MIB in detail and the application way of MIB in network management .The thesis also assays the ICMP protocol, describing its working principle and the format of datagram minutely , and describing two important tools of ICMP- Ping and TraceRoute in detail. On the base of upper analysis, the thesis expounds a kind of distributed Topology Discovery project, and book it in one autonomy system. Topology Discovery was divided into two levels in terms of network management, and analyses the way of linking up between the two level. The thesis minutely assays Router-Level Topology Discovery technology basing on SNMP and Subnet-Level Topology Discovery technology basing on ARP and ICMP. According to these analyses, the thesis explores the specific methodology and the technology of XML data object which using the WinSNMP API to achieve topology discovering system on the development platform of Visual C++, and also analyses the technology of topology analysis and topology graph minutely. Moreover, the thesis assays the technology of basic firewall and Topology Discovery response strategy. Finally, the thesis analyses the underlying blind problem of the topology finding, and also analyses the reason that the blind problem produced and the way that reduced. The distributed algorithm that this paper puts forward has a certain directive significance in wireless network or other fields.

本文首先分析了网络结构状况，将网络从网络管理的角度划分为三个层次，为分布式的方法奠定了基础，同时还指出拓扑发现研究的目的及意义；接着本文分析了SNMP协议，详细分析了SNMP协议的发展状况，协议的工作原理，以及由SNMP协议基础上建立的SNMP网络管理体系，详细分析了MIB，以及MIB在网络管理上的应用方式；本文又分析了ICMP协议，详细描述了ICMP的工作原理和数据报格式，并详细描述了ICMP的两个重要工具-Ping 和TraceRoute；然后本文在结合上述分析的基础上，提出了一种分布式的拓扑发现方案，将拓扑发现拟订在一个自治系统内，将拓扑发现从网络管理角度划分为路由器级和子网级两个层次，分析了两个层次之间的衔接方式，同时从拓扑地域的角度将拓扑发现过程分布化，分析了分布式算法的具体方法和分布式结点之间的数据通讯方法，本文详细分析了基于SNMP的路由器级拓扑发现技术和基于ARP和ICMP的子网级拓扑发现技术；根据这些分析，本文利用XML数据对象作为分布式算法中的数据对象，分析了XML的技术，本文使用Visual C++开发平台实现网络拓扑发现系统，详细分析了使用WinSNMP API实现基于SNMP的路由器级拓扑发现和基于ARP的子网级拓扑发现，分析了使用Winsock编程实现基于ICMP的子网级拓扑发现，本文还对拓扑分析和拓扑图的绘制技术作了较细致的分析；本文最后还分析了基本防火墙技术，分析了几种类型的防火墙对拓扑发现带来的影响，以及在拓扑发现时的应对策略，本文还分析了拓扑发现中可能产生的盲点问题，分析了盲点产生的原因以及拓扑发现中减少盲点的方法。

Because the Petri net can describe intuitionally system characteristics, such as the system's dynamic, asynchronous, concurrent and so on, it very suits to describe the Discrete Event Dynamic System such as logistics system.

本文首先对制造企业内部的几个基本生产过程中的物流进行了分析，分别建立了拉动式生产系统Petri网物流模型、推动式生产系统Petri网物流模型、流水线生产的Petri网物流模型及混合生产线的Petri网物流模型等。

In organization level, design activity fragmentizing strategy and negotiation mechanism are applied to schedule the collaborative design process. To present the uncertainty in design, resource sharing, message passing and real-timed interaction between programs, the integrated control Petri net is adopted to model and simulate the collaborative level. Control level is realized by workflow model, which control the tasks in collaborative design by means of user management, access control and task control rules.

本文通过细化设计活动策略和协商机制，实现了组织级的协同设计过程规划；针对常用的有色Petri网方法不能解决实际系统运行中出现的不确定性、资源共享、信息传递和外部程序的实时交互等问题，通过对有色Petri网的扩充，提出了采用集控Petri网方法，用于协调级的建模和仿真；采用工作流模型为控制级实现，从用户管理、访问控制模型、协同任务控制规则三个方面实现协同设计过程的任务流控制。

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。

In MicroGrid if traditional synchronous generators were used as the main power support, the frequency of MicroGrid would fluctuate greatly during MicroGrid operated from isolated mode to grid-connected mode, and some distributed generations maybe were disconnected from the grid by low frequency relay.

如果选择微型燃气轮机作为微网的主要功率支撑手段，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。

Primary innovative work in this paper can be summarized as follows: 1 Based on the Workflow Management System reference model and Workflow Management System frame presented by Wil Va Der Aalst, Wei-kuang Huang ect, we construct a secure Workflow Management System frame with secure characteristic.

2针对基于任务过程模型的不足，分析了基于角色的过程模型，在对象Petri网过程模型中加入角色的概念，构建了一个基于角色的对象Petri网工作流模型。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失