一类新型 PWM 可逆整流器

针对传统的桥式ＰＷＭ可逆整流器直流侧工作电压要求较高的限制,提出一种新型ＰＷＭ可逆整流器拓扑,运用状态空间平均法进行了建模和稳态理论分析,并给出该变流器的参数选择方法。ＭＡＴＬＡＢ数值仿真与样机实验结果证实了该拓扑、模型及理论的正确性。     

关联规则发现:综述

围绕ＫＤＤ的一个重要发现任务──关联规则发现,介绍了这一领域基本概念、处理技术以及面临的问题。     

STL面片邻接拓扑关系重构及其应用

STL文件描述的是一种离散的实体表面三角面片模型,在实际处理中一般需要重新构造其邻接拓扑关系(包括面片的邻接面、顶点的邻接面、邻接顶点等关系）。而剔除STL面片数据中的冗余顶点是重构的关键,该算法已经成功应用于三维真实感注塑模流动模拟软件的3D图形处理。     

无线传感网络中通用传感器节点硬件结构设计

无线传感网络是当前国内外传感器技术领域的热点研究课题。提出了一种构建无线传感网络节点实验平台的方法;基于该设计方案实现的无线传感网络节点可以有效地组建网络拓扑结构及多种传感数据采集传输。它还可以用于实现声音空间定位系统。关键词:无线传感网络;节点;拓扑结构;数据采集;声音空间定位     

基于Agent的UDDI研究

本文研究如何运用Agent技术实现Web服务的发布扣发现，并给出了一个参考模型。Agent具有智能性。容易发现Web服务；Web服务方便现有异构软件资源的集成。故本文建议在Web服务扣Agent技术之间构建一个过渡阶段，即吸取Agent技术的一些特点来改造Web服务。     

一种非结构化P2P的随机有向图拓扑模型

在非结构化P2P系统中,P2P拓扑直接影响了网络的性能,如何构建P2P拓扑是一件重要的问题.采用一个简单的映射将非结构化P2P抽象成一个G(V,E)图,在G(V,E)及其非结构化P2P拓扑的特点基础上,提出了一种非结构化P2P的随机有向图拓扑模型,并讨论了该拓扑模型的度分布、连通性和直径,为研究非结构化P2P系统的性能和算法协议提供了仿真的理论基础.     

知识发现在农业生产中的应用研究

文章通过对基于数据库的知识发现系统(KDD)的研究,提出了双库协同机制,它改变了KDD的结构、运行过程与机制,形成新的知识发现系统KDD。将该发现系统应用于农业领域,为合理地指导农业生产提供了科学的决策,因而具有重要的理论意义和实用价值。     

桥接局域网第2层拓扑结构的自动发现

With the rapid development and the wide use of Bridged Local Area Networks, the importance of below-OSI-Layer-3 topology comes to be realized. Recent research work has demonstrated that active layer-2 topology can be determined using Address Forwarding Information. The large quantities of address forwarding entries in a typical BLAN, however, make their algorithms both time-consuming and bandwidth-consuming. In view of the above and the fact that transparent bridges are used preponderantly in real networks, we base our algorithm on information supported by Spanning Tree Protocol M1B group, which reduces the cost of acquiring and processing information, and improves the accuracy. Our algorithm relies on standard MIB information and can be used in heterogeneous environments     

Exploring networks with traceroute-like probes: Theory and simulations

Mapping the Internet generally consists in sampling the network from a limited set of sources by using traceroute-like probes. This methodology, akin to the merging of different spanning trees to a set of destination, has been argued to introduce uncontrolled sampling biases that might produce statistical properties of the sampled graph which sharply differ from the original ones. In this paper, we explore these biases and provide a statistical analysis of their origin. We derive an analytical approximation for the probability of edge and vertex detection that exploits the role of the number of sources and targets and allows us to relate the global topological properties of the underlying network with the statistical accuracy of the sampled graph. In particular, we find that the edge and vertex detection probability depends on the betweenness centrality of each element. This allows us to show that shortest path routed sampling provides a better characterization of underlying graphs with broad distributions of connectivity. We complement the analytical discussion with a throughout numerical investigation of simulated mapping strategies in network models with different topologies. We show that sampled graphs provide a fair qualitative characterization of the statistical properties of the original networks in a fair range of different strategies and exploration parameters. Moreover, we characterize the level of redundancy and completeness of the exploration process as a function of the topological properties of the network. Finally, we study numerically how the fraction of vertices and edges discovered in the sampled graph depends on the particular deployements of probing sources. The results might hint the steps toward more efficient mapping strategies.     

基于N线的拓扑感知技术研究

随着科技革新与能源革命的深度融合,国家电网作为世界一流企业,提出了"推进电网向能源互联网转型升级"的口号;电网是由发电、输电、配电、用电等各类品种繁多的挂网设备组成的复杂系统,明晰挂网产品的拓扑网络,提高电网的智能化感知能力,及时消除安全隐患,确保电网健康、稳定运行成为当前最为迫切的任务;在对电网拓扑结构的研究过程中,提出了基于N线的拓扑感知技术,依据电流沿阻抗最小回路传输原理,采用现代微机处理与控制技术;经实验测试实现了针对电力N线的特征电流信号注入、检测和识别,降低了对挂网设备的影响;可以方便、快捷地接入台区变压器及各级分支箱侧,实现挂网设备的智能化拓扑识别,方便故障点的锁定,第一时间切断故障点电能供给,及时维修故障,确保电力正常、高效的供应。