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民用飞机燃油箱固有安全线路设计的研究 被引量:2
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作者 陈卓 李庆南 《航空制造技术》 北大核心 2014年第4期66-68,73,共4页
针对民用飞机进入燃油箱的固有安全线路进行分析,提出设计思路,并通过试验计算的分析方法验证燃油箱的固有安全线路满足安全性要求。
关键词 点火源 固有安全线路
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10kV全线路核相新方法 被引量:3
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作者 王胜东 《电工技术》 2011年第6期62-62,66,共2页
介绍一种新的10kV全线路核相方法,并阐述其原理、核相时需要的工具及注意事项。
关键词 全线路 核相 电流 相位
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老型号XPM-71型电梯安全线路的完善与改进
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作者 陈传平 《电世界》 1996年第5期15-15,共1页
我厂装用一台1987年生产的XPM-71型客货两用梯,使用中发现安全方面未按国家现有标准(即国标GB7588(国家电梯制造与安装安全规范》,GB10059—87《电梯技术条件》,GB10060—93《电梯安全验收规范》)执行,主要有: (1)供电系统未设置断相、... 我厂装用一台1987年生产的XPM-71型客货两用梯,使用中发现安全方面未按国家现有标准(即国标GB7588(国家电梯制造与安装安全规范》,GB10059—87《电梯技术条件》,GB10060—93《电梯安全验收规范》)执行,主要有: (1)供电系统未设置断相、错相保护装置。 (2)轿厢顶部无检修操纵箱。 展开更多
关键词 电梯 全线路 供电系统
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500kV同塔四回输电线路全线雷击特性研究
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作者 刘志伟 赵会龙 +2 位作者 刘巍 茅鑫同 周俊 《电力设备管理》 2024年第1期21-23,共3页
本文通过统计500 kV同塔四回输电线路的结构参数、沿线雷电活动参数等,利用MATLAB编程和ATP-EMTP搭建全线仿真模型,计算了全线路的雷电绕击和反击特性。研究发现,输电线路第三层导线易发生绕击,直线塔第二层和耐张塔第一层导线易发生反... 本文通过统计500 kV同塔四回输电线路的结构参数、沿线雷电活动参数等,利用MATLAB编程和ATP-EMTP搭建全线仿真模型,计算了全线路的雷电绕击和反击特性。研究发现,输电线路第三层导线易发生绕击,直线塔第二层和耐张塔第一层导线易发生反击。全线综合雷击跳闸率满足规程规范指标,但直线型高杆塔#97、#111、#112的雷电反击跳闸率较高,且直线型杆塔的平均雷击跳闸率高于耐张型杆塔。 展开更多
关键词 同塔四回 雷击特性 全线路
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四回非全线平行线路零序分布参数测量方法 被引量:2
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作者 高明鑫 胡志坚 +2 位作者 倪识远 张志毅 牟洪江 《电工技术学报》 EI CSCD 北大核心 2022年第6期1351-1364,共14页
随着电力系统的不断发展,输电走廊日益狭窄,四回线路共用一部分走廊的情况非常普遍,目前尚未有相应的线路分布参数测量方法。该文提出一种四回非全线平行线路分布参数精确测量方法,建立四回非全线平行线路的非均匀传输线模型,通过拉普... 随着电力系统的不断发展,输电走廊日益狭窄,四回线路共用一部分走廊的情况非常普遍,目前尚未有相应的线路分布参数测量方法。该文提出一种四回非全线平行线路分布参数精确测量方法,建立四回非全线平行线路的非均匀传输线模型,通过拉普拉斯变换完整地得到四回线路的传输矩阵,获得线路分布参数与线路两端的电压、电流之间关系的数学表达式。在四种独立测量方式下同步测量四回非全线平行线路首末两端的零序电压与零序电流,代入该文所提计算公式,精确求解出24个零序分布参数。通过PSCAD仿真软件证明了该文方法的准确性,并与现有测量方法进行了比较。仿真结果表明,该文方法较现有测量方法具有更高的测量精度。 展开更多
关键词 四回非全线平行线 非均匀传输线 零序分布参数 拉普拉斯变换 同步测量
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多功能内燃设备电路保护系统
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《林业劳动安全》 1995年第2期14-14,共1页
多功能内燃设备电路保护系统该装置在内燃设备发生短路、蓄电池大量放电将要发生火灾时,比以往的保护措施能更迅速、自动、长时间地切断短路电源,防止火灾发生。通过短路信号显示发生短路原因,以便尽快排除。在短路未排除之前,误认... 多功能内燃设备电路保护系统该装置在内燃设备发生短路、蓄电池大量放电将要发生火灾时,比以往的保护措施能更迅速、自动、长时间地切断短路电源,防止火灾发生。通过短路信号显示发生短路原因,以便尽快排除。在短路未排除之前,误认为已经排除,要恢复原线路工作时,保... 展开更多
关键词 保护 内燃 发动机 微机控制 自动切断电源 保护装置 保护措施 蓄电池电源 安全运行 全线路
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考虑输电线路安全的机械除冰次序优化 被引量:6
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作者 程松 郁琛 +3 位作者 吴琛 黄琳雁 褚云龙 崔伟 《中国电力》 CSCD 北大核心 2018年第1期71-77,共7页
机械除冰是应对输电线路覆冰灾害的重要手段,现有研究主要集中在除冰方法的改进,而对机械除冰实施过程的影响研究较少。研究发现在机械除冰过程中,如果按照从输电线路一端开始顺序除冰的策略,杆塔承受的最大不平衡力可能超过设计标准,... 机械除冰是应对输电线路覆冰灾害的重要手段,现有研究主要集中在除冰方法的改进,而对机械除冰实施过程的影响研究较少。研究发现在机械除冰过程中,如果按照从输电线路一端开始顺序除冰的策略,杆塔承受的最大不平衡力可能超过设计标准,影响输电线路安全,而不同的除冰次序会产生不同的最大不平衡力。为此,有必要对机械除冰的除冰次序进行优化,提高机械除冰的安全性。首先分析了机械除冰过程中除冰次序对杆塔平衡力的影响,然后建立了输电线路机械除冰次序优化模型。由于该模型为非线性、多约束模型,采用遗传算法对不同档导线覆冰清除的次序进行优化。仿真分析表明,优化后的除冰次序能够有效地降低杆塔承受不平衡力,提高机械除冰过程中输电线路的安全性。 展开更多
关键词 输电线 覆冰灾害 机械除冰 遗传算法 次序优化
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现代汽车混合动力技术概述(十五)
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作者 凌风 《汽车维修技师》 2013年第11期48-50,共3页
混合动力系统可以运转。安全连接器与高压线路的锁定棘爪相连。如果不得不断开安全线路,则必须抽出安全连接器。高压系统维修连接器TW:连接器安装于电气盒橙色盖子下,如图89所示。维修连接器是高压电池组中两组蓄电池之间的电气连接器... 混合动力系统可以运转。安全连接器与高压线路的锁定棘爪相连。如果不得不断开安全线路,则必须抽出安全连接器。高压系统维修连接器TW:连接器安装于电气盒橙色盖子下,如图89所示。维修连接器是高压电池组中两组蓄电池之间的电气连接器。当抽出连接器时,电池电路的连接被切断。高压系统内的残余电压消失。此时,高压系统不带电。通常当必须对高压元件进行操作,或在高压元件附近使用金属切削,金属变形加工工具或带有锐利边缘的工具进行作业时。 展开更多
关键词 连接器 高压电池组 高压系统 高压线 功率电 混合动力系统 保护继电器 全线路 控制单元 系统维修
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Discussion on the Mode of China's Low-carbon Society and Construction Routes 被引量:1
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作者 Li Mingsheng Yuan Li 《Chinese Journal of Population,Resources and Environment》 2012年第1期13-18,共6页
In responding to global climate change,the idea of low-carbon economy emerges as the times require.Developing low-carbon economy is based on the construction of low-carbon society.The so called "two-orientation s... In responding to global climate change,the idea of low-carbon economy emerges as the times require.Developing low-carbon economy is based on the construction of low-carbon society.The so called "two-orientation society"(resources conservation orientated society and environmental friendly orientated society) is the concrete representation of low-carbon society with Chinese characteristics,and an actual action for China in developing low-carbon economy.Based on urban agglomeration,the paper discusses the meaning of and the route to low-carbon society which would better reflect the intrinsic requirements of such a society. 展开更多
关键词 low-carbon economy low-carbon society urban ag- glomeration LAND
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Research on the stability analysis and design of soil tunnel surrounding rock 被引量:2
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作者 Zheng Yingren Qiu Chenyu Xiao Qiang 《Engineering Sciences》 EI 2010年第3期57-70,共14页
The paper first analyzes the failure mechanism and mode of tunnel according to model experiments and mechanical calculation and then discusses the deficiency of taking the limit value of displacement around the tunnel... The paper first analyzes the failure mechanism and mode of tunnel according to model experiments and mechanical calculation and then discusses the deficiency of taking the limit value of displacement around the tunnel and the size of the plastic zone of surrounding rock as the criterion of stability. So the writers put forward the idea that the safety factor of surrounding rock calculated through strength reduction FEM(finit element method) should be regarded as the criterion of stability,which has strict mechanical basis and unified standard and would not be influenced by other factors. The paper also studies the safety factors of tunnel surrounding rock (safety factors of shear and tension failure) and lining and some methods of designing and calculating tunnels. At last,the writers take the loess tunnel for instance and show the design and calculation results of two-lane railway tunnel. 展开更多
关键词 stability of tunnel surrounding rock strength reduction FEM safety factor of shear safety factor of tension failure design method of tunnel
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Building a highly available and intrusion tolerant database security and protection system ( DSPS) 被引量:2
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作者 蔡亮 杨小虎 董金祥 《Journal of Zhejiang University Science》 EI CSCD 2003年第3期287-293,共7页
Database Security and Protection System (DSPS) is a security platform for fighting malicious DBMS. The security and performance are critical to DSPS. The authors suggested a key management scheme by combining the serv... Database Security and Protection System (DSPS) is a security platform for fighting malicious DBMS. The security and performance are critical to DSPS. The authors suggested a key management scheme by combining the server group structure to improve availability and the key distribution structure needed by proactive security. This paper detailed the implementation of proactive security in DSPS. After thorough performance analysis, the authors concluded that the performance difference between the replicated mechanism and proactive mechanism becomes smaller and smaller with increasing number of concurrent connections; and that proactive security is very useful and practical for large, critical applications. 展开更多
关键词 Information warfare Proactive security Intrusion tolerant DSPS(Database Security and Protection System)
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In Situ Experiments on Supporting Load Effect of Large-span Deep Tunnels in Hard Rock 被引量:4
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作者 HE Ben-guo ZHU Yong-quan +2 位作者 SUN Ming-lei LIU Hong-yan ZHANG Zhi-qiang 《Journal of Mountain Science》 SCIE CSCD 2013年第6期1125-1136,共12页
A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for... A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for the tunnel was300 m2and is classified as the largest cross section for railway tunnels in China. Through in situ experimental studies, mechanistic properties of the tunnel were identified, including the surrounding rock pressure, convergences along tunnel perimeter and safety of primary support and lining structure.Based on the field measured data, the surrounding rock pressure demand for large-span deep tunnel in hard rock is recommended as double peak type in the vertical direction and fold line type was recommended for horizontal pressure. The results suggested that Promojiyfakonov's theory was most close to the monitored value. Specific recommendations were also generated for the use of bolts in tunnel structures.Numerical simulation was used to evaluate the safety of the tunnel and it confirmed that the current design can satisfy the requirement of the current code. 展开更多
关键词 Large-span tunnel Railway tunnel Surrounding rock pressure Load distribution In situ experiment
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Investigation on the threshold control of safety blasting vibration velocity for the extraction of complicated orebody under railway 被引量:6
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作者 Jiang Lichunt Hu Liuqing Lai Xiuying 《Mining Science and Technology》 EI CAS 2011年第2期169-174,共6页
The threshold control of safety blasting vibration velocity is a significant process for the underground mining of complicated ore deposit under construction,road,and water.According to the equivalent principle of dis... The threshold control of safety blasting vibration velocity is a significant process for the underground mining of complicated ore deposit under construction,road,and water.According to the equivalent principle of displacement and velocity of mass point,differential evolution is put forward based on 3DEC dynamic analysis,making the calculation more efficient and accurate.The 3DEC model of the complicated orebody under railway is established according to the topographic maps and geological data of the eastern Pyrite Mine.The stimulus-response distribution of internal stress and displacement fields are demonstrated by analyzing the on-site monitoring vibration displacement and velocity data of the mass point.The reliability of parameter selection,such as blasting simulation waveforms,rock damping,is identified.The safety vibration velocity of railway is set to 4.5 cm/s in line with the requirement of safety blasting rules.Thus,the maximum amount of single-stage explosive in this region is 44.978 kg.The simulation result is in good agreement with the on-site monitoring datum.No displacement and settlement of the 701 railway special line was achieved by choosing the critical amount of the single-stage explosive. 展开更多
关键词 Mining under construction Road and water Blasting vibration The method of differential evolution Safety velocity Amount of single-stage explosive
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Distributed Low-Complexity Channel Assignment for Opportunistic Routing 被引量:2
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作者 He Shiming Zhang Dafang +2 位作者 Xie Kun Qiao Hong Zhang Ji 《China Communications》 SCIE CSCD 2012年第11期9-22,共14页
Opportunistic Routing (OR) involves multiple forwarding candidates to relay packets by taking advantage of the broadcast nature and multi-user diversity of a wireless medium. Compared with Traditional Routing (TR), OR... Opportunistic Routing (OR) involves multiple forwarding candidates to relay packets by taking advantage of the broadcast nature and multi-user diversity of a wireless medium. Compared with Traditional Routing (TR), OR is more suitable in the case of an unreliable wireless link and can evidently improve the end-to-end throughput of Wireless Mesh Networks (WMNs). In this paper, we focus on OR in Multi-Radio Multi-Channel WMNs (MRMC-WMNs). This problem has not been well examined and is considerably more challenging than the OR in single-radio wireless networks considered in the existing literature. First, we validate the advantage of OR in MRMC-WMNs. Second, we propose Low-complexity Channel Assignment for Opportunistic Routing (LcCAOR), which assigns channels to flows according to the interference state of every node. Third, we implement the LcCOAR in a fully distributed manner. The simulation result shows that compared with OR in Single-Radio Single-Channel WMNs (SRSC-WMNs), the proposed OR can significantly enhance the throughput to 87.11% and 100.3% in grid and tree WMNs, respectively. 展开更多
关键词 wireless mesh networks multi-radio and multi-channel opportunistic routing channel assignment
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Development of a Genetic Algorithm for Evaluating the Performance of Overhead Power Distribution Lines and Proposing Solutions to Improve Distribution Line Safety
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作者 Fabio Romero Alden U. Antunes +4 位作者 Dario Takahata Andre Meffe Carlos C. B. Oliveira Femando L. Lange Hamilton Souza 《Journal of Energy and Power Engineering》 2015年第1期78-82,共5页
This paper aims to present and discuss the use of a power flow methodology based on Gauss elimination method to evaluate the performance of distribution network taking into account the neutral conductor absence at spe... This paper aims to present and discuss the use of a power flow methodology based on Gauss elimination method to evaluate the performance of distribution network taking into account the neutral conductor absence at specific sections, and a development of a methodology based on GA (genetic algorithm) capable of evaluating alternative solutions in different bars of the feeder, in order to propose appropriate solutions to improve the distribution network safety. Besides the technical aspects, the proposed GA methodology takes into account the economic feasibility analysis. The results of power flow simulations have shown that the presence of single-phase transformers along with the absence of the neutral conductor at specific sections of the MV (medium voltage) network may increase the Vng (neutral-to-ground voltage) levels of the feeders involved, jeopardizing the system's safety. On the other hand, the solutions proposed by the GA methodology may reduce the network Vng levels and improve the safety conditions, providing values close to the ones found before the neutral conductor theft. 展开更多
关键词 Genetic algorithm power flow distribution line safety power flow simulation
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A multipath routing protocol for wireless sensor network for mine security monitoring 被引量:7
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作者 XIAO Shuo WEI Xueye WANG Yu 《Mining Science and Technology》 EI CAS 2010年第1期148-151,共4页
Underground mining is a hazardous industrial activity. In order to provide a safe working environment for miners, a Wireless Sensor Network (WSN) technology has been used for security monitoring. It can provide a wide... Underground mining is a hazardous industrial activity. In order to provide a safe working environment for miners, a Wireless Sensor Network (WSN) technology has been used for security monitoring. It can provide a wide range of surveillance with a relatively low cost. In this study, an Energy-Based Multipath Routing (EBMR) protocol is proposed, which considers residual energy capacity and link quality in choosing hops and routing paths. Hops and paths with a high residual energy capacity and link quality will have the best chance to be selected to transmit data packages. Since the EBMR stores several routes in the routing table, when the current path fails, another path will be chosen to fulfill the task immediately. In this way, EBMR improves reliability and decrease time latency. Compared to AOMDV and REAR, EBMR decreases time latency by 51% and 12%. 展开更多
关键词 coal mine security monitoring multipath routing wireless sensor network
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Research on Safety and Stability of Regional Power Grids to the Year 2020
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作者 Zhou Qinyong Zhao Liang +1 位作者 Guo Qiang Jin Wen 《Electricity》 2005年第3期26-31,共6页
The safety and stability study on Northeast, North, East, Northwest and Central China power grids had been carried out, which provided technical supports to planning design of regional power grids. By analyzing safety... The safety and stability study on Northeast, North, East, Northwest and Central China power grids had been carried out, which provided technical supports to planning design of regional power grids. By analyzing safety and stability under severe faults in regional power grids, revealed weaknesses on power grid configurations and measures for preventing from loss of stability were presented. In comparison of various schemes of power system safety and stability among parts of power grids, more than two recommended schemes can be chosen as reference in planning design for regional power grids. Considering the safety and stability control measures necessary for each power grids, it is believed the trunk networks of all power grids can fulfill the third criteria of Guideline for Power System Safety and Stability, while the weakness and predominated hydropower may deteriorate safety and stability of power grids. The power grid shall be regulated in line with the variation of boundary conditions. 展开更多
关键词 regional power grid safe and stable power grid planning power system
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Prototype Monitoring System for Power Line Inspection by Means of a PandaBoard
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作者 Rupert Gouws Tjaart Visser 《Journal of Energy and Power Engineering》 2014年第1期176-182,共7页
The national energy supplier (Eskom in South Africa) supplies electricity through thousands-of-kilometers of overhead power lines. The current methods of inspection of these overhead power lines are infrequent and e... The national energy supplier (Eskom in South Africa) supplies electricity through thousands-of-kilometers of overhead power lines. The current methods of inspection of these overhead power lines are infrequent and expensive. In this paper, the authors present the development of a prototype monitoring system for power line inspection in South Africa. The developed prototype monitoring system collects data (information) from the overhead power lines, is remotely accessible and fits into a power line robot. The prototype monitoring system makes use ofa PandaBoard (SBC) with GPS receiver and 5 MP camera to collect data. Hardware fatigue is the biggest problem faced on the overhead power lines and is captured by means of the 5 MP camera and is displayed on a website hosted by the PandaBoard via Wi-Fi. The monitoring system has low power consumption, is light weight, compact and easily collects data. The data obtained from the prototype monitoring system was satisfactory and provides an improved solution for monitoring power lines for Eskom in South Africa. 展开更多
关键词 Inspection robot monitoring system PandaBoard transmission line inspection.
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现代网球技战术名家精华(续第二期)
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作者 Craig Tiley 张伟 《网球天地》 2003年第4期50-52,共3页
国际网球联合会邀请了几位当今世界上最优秀的网球教练,请他们向大家介绍现代职业网球运动员的打法和战术,如底线型选手战术、上网型选手战术、全能型战术、沙土场地上使用的战术、硬地球场上使用的战术和左手持拍者所使用的战术等。他... 国际网球联合会邀请了几位当今世界上最优秀的网球教练,请他们向大家介绍现代职业网球运动员的打法和战术,如底线型选手战术、上网型选手战术、全能型战术、沙土场地上使用的战术、硬地球场上使用的战术和左手持拍者所使用的战术等。他们曾分别担任过阿加西、桑普拉斯、哈斯、皮尔斯、施蒂希、塞莱斯和费雷罗的教练,以及网球强国的戴维斯杯或联合会杯的队长。他们的观点对当今的网球战术起着举足轻重的作用,并且有些理论也已成为如今培养优秀网球选手的法宝。 现将国际网联整理的这些著名教练员的有关网球战术的系统文章翻译出来,以供我国的网球教练员学习和参考。 展开更多
关键词 网球选手 战术意识 拦网 精华 斜线球 区域网 网球运动员 练习方法 全线路 发球效果
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Personal continuous route pattern mining 被引量:1
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作者 Qian YE Ling CHEN Gen-cai CHEN 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第2期221-231,共11页
In the daily life,people often repeat regular routes in certain periods. In this paper,a mining system is developed to find the continuous route patterns of personal past trips. In order to count the diversity of pers... In the daily life,people often repeat regular routes in certain periods. In this paper,a mining system is developed to find the continuous route patterns of personal past trips. In order to count the diversity of personal moving status,the mining system employs the adaptive GPS data recording and five data filters to guarantee the clean trips data. The mining system uses a client/server architecture to protect personal privacy and to reduce the computational load. The server conducts the main mining procedure but with insufficient information to recover real personal routes. In order to improve the scalability of sequential pattern mining,a novel pattern mining algorithm,continuous route pattern mining(CRPM),is proposed. This algorithm can tolerate the different disturbances in real routes and extract the frequent patterns. Experimental results based on nine persons' trips show that CRPM can extract more than two times longer route patterns than the traditional route pattern mining algorithms. 展开更多
关键词 Data mining Route pattern GPS Mobile phone
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