多局部放电源定位中去除交叉定位虚假点的快速算法

针对测向交叉定位法在对放电信号进行分析以获得放电源位置信息时,存在多放电源情况下大量的虚假定位问题,利用3个传感器阵列,采用基准线最小距离法来排除交叉定位中的虚假点:首先使用多重信号分类对多个局部放电源进行观测和计算,得到各个信号源的方位;然后利用基准线最小距离法去除交叉定位中的虚假点.仿真结果表明了该方法的有效性和实用性.     

基于PLC技术的VIGAN卸船机控制系统故障诊断

本文根据VIGAN卸船机控制系统分析了基于PLC技术的故障诊断设计。     

A new and accurate fault location algorithm for combined transmission lines using Adaptive Network-Based Fuzzy Inference System

This paper presents a new and accurate algorithm for locating faults in a combined overhead transmission line with underground power cable using Adaptive Network-Based Fuzzy Inference System (ANFIS). The proposed method uses 10 ANFIS networks and consists of 3 stages, including fault type classification, faulty section detection and exact fault location. In the first part, an ANFIS is used to determine the fault type, applying four inputs, i.e., fundamental component of three phase currents and zero sequence current. Another ANFIS network is used to detect the faulty section, whether the fault is on the overhead line or on the underground cable. Other eight ANFIS networks are utilized to pinpoint the faults (two for each fault type). Four inputs, i.e., the dc component of the current, fundamental frequency of the voltage and current and the angle between them, are used to train the neuro-fuzzy inference systems in order to accurately locate the faults on each part of the combined line. The proposed method is evaluated under different fault conditions such as different fault locations, different fault inception angles and different fault resistances. Simulation results confirm that the proposed method can be used as an efficient means for accurate fault location on the combined transmission lines.     

蜂窝电话定位系统技术与性能分析

近年来,定位技术在许多领域得到了广泛应用,随着蜂窝电话的普及、蜂窝电话定位系统的理论研究与应用开发工作也在不停地进行着,人们提出了多种方案,它们各有特点,需要依据一系列的性能指标对其整体性能进行分析。     

基于电压暂降测量的配电网故障自动定位

文中提出了一种结合电力系统分析程序、数据库检索方法和模式识别技术自动识别的11kV配电网故障定位方法。该方法采用三相不平衡潮流和故障分析程序,对配电网各节点的故障进行分析生成电压暂降数据库,设计了数据库搜索和模式识别算法,以便配电网在发生实际故障时识别故障位置。利用电力系统EMTDC模拟器对该方法进行了评估和测试。实验结果表明,提出的线性模式识别算法能够识别所研究的11kV配电网的大部分故障区段。     

地市级地面数字电视发射机常见故障分析

随着中国加快推进地面数字电视（DTMB）无线覆盖工程的建设,提高技术人员对地面数字电视发射系统设备的维护维修水平、故障判断排除能力刻不容缓。本文结合由包头市微波总站建设的市级地面数字电视单频网项目,对其运行中常见的发射机故障进行了分析和总结。     

学生信息管理系统

设计了学生信息管理系统来解决学校学生信息管理方面不完善问题,此系统分为基本信息管理、疫苗信息管理和位置管理三个模块,通过收集学生的基本信息,疫苗详细信息和学生位置变化信息,提高学校收集管理学生信息的时间效率以及减少统计错误等问题。     

基于无线电测向的台站定位

无线电定位技术有看广泛的应用前景，基于无线电测向的台站定位，推导出了平面和球面双站定位算法，给出了多站定位算法，并对以上算法进行了实例计算，验证了算法的正确性。平面和球面台站定位算法对于台站定位有很好的实用性，尤其是球面定位算法对于提高定位精度有很大的作用。     

无源测向测时差定位算法研究

该文首先给出了无源测向测时差定位算法,然后对该算法的定位精度进行了分析。通过仿真将该方法与无源测向交叉法和时差法进行了比较,说明该方法是一种定位精度较高且对系统要求较低的无源定位方法,具有实用价值。     

Indoor Ad Hoc Proximity-Location Sensing for Service Provider Selection

There are protocols that can be used by mobile clients to discover service providers in foreign networks to which they get attached, e.g., SDP of Bluetooth and SLP of IETF. These protocols do address service discovery, but do not address the selection of a service provider among a set of candidates according to a physical proximity of the client and service provider. The goal of the research described in this paper is to integrate proximity-based selection mechanisms to service discovery protocols. We present in this paper protocols that allow nomadic clients to discover and select service providers according to physical proximity.