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基于Ferry Borges理论的地震与重卡车作用下桥梁内力的组合问题 被引量:5
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作者 孙得璋 孙柏涛 George C.Lee 《地震工程与工程振动》 CSCD 北大核心 2011年第6期18-23,共6页
目前的AASHTO LRFD桥梁规范主要考虑重力荷载和卡车等活荷载的组合情况,而没有在概率基础上考虑地震等极端荷载的组合问题。包括LRFD在内的很多桥梁抗震规范都是主要考虑地震的作用,甚至设计时不考虑其他荷载的作用,LRFD设计指导手册中... 目前的AASHTO LRFD桥梁规范主要考虑重力荷载和卡车等活荷载的组合情况,而没有在概率基础上考虑地震等极端荷载的组合问题。包括LRFD在内的很多桥梁抗震规范都是主要考虑地震的作用,甚至设计时不考虑其他荷载的作用,LRFD设计指导手册中在考虑地震等极端荷载时,也只是提到在特殊情况和桥梁比较长的情况下再考虑卡车的作用,而且,也比较模糊。文中在考虑地震荷载与卡车荷载时将其视为2种随机过程函数,并分析其各自的荷载特点。结合最近一些年USGS收集的极端荷载数据,文中认为桥梁设计(考虑地震和重卡车设计)时应该综合考虑地震和重卡车的影响,对它们进行荷载组合。接着,文中简单回顾了几种荷载组合方法,对比之后,认为FerryBorges(也称Ferry Borges-Castanheta模型)模型考虑了荷载的持时因素与荷载发生概率,虽然也对荷载做了极大的简化,但很好地解释了随机过程转化成随机变量以及与其他随机变量组合的复杂问题。最后,本文以美国西雅图地区的一桥梁为研究对象进行了算例分析。 展开更多
关键词 LRFD 极端荷载 随机过程 荷载组合 地震与重卡车 ferry Borges 桥梁设计
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DTN网络中Ferry节点的MSSL路由算法研究 被引量:4
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作者 章韵 魏鹏 +1 位作者 王汝传 王绍棣 《计算机技术与发展》 2009年第5期107-110,118,共5页
在节点移动规律无法预知、连通性较差的延迟容忍网络中,针对DTN网络的Ferry节点自定位方案,能够有效提高网络中数据信息采集效率。该方案能够在节点移动过程中根据一个修正因子不断对Ferry的移动节点坐标进行调整,最后使坐标收敛到一个... 在节点移动规律无法预知、连通性较差的延迟容忍网络中,针对DTN网络的Ferry节点自定位方案,能够有效提高网络中数据信息采集效率。该方案能够在节点移动过程中根据一个修正因子不断对Ferry的移动节点坐标进行调整,最后使坐标收敛到一个可用的范围。通过概率路由算法对Ferry节点的移动路线优化,使得Ferry节点能够在有限时间内最大限度地收集信息。实验证明,该方案通过合适的修正因子调整节点坐标,使路由算法具有良好的稳定性,在节点信息传输率、公平性和延迟性方面有良好的表现。 展开更多
关键词 延迟容忍网络 ferry路由设计 移动空间自定位
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延迟容忍网络中多Ferry路由设计及改进 被引量:3
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作者 章韵 王磊 《计算机工程与设计》 CSCD 北大核心 2009年第24期5605-5608,共4页
针对延迟容忍网络多Ferry路由设计方案MRT-Tree中普通节点的缓存和能量消耗过多的不足之处,提出了星型拓扑多Ferry路由设计MRT-Star。新设计使用专用的缓存装置来取代普通节点作为转发节点,并改变了普通节点的分配方式和Ferry节点的交... 针对延迟容忍网络多Ferry路由设计方案MRT-Tree中普通节点的缓存和能量消耗过多的不足之处,提出了星型拓扑多Ferry路由设计MRT-Star。新设计使用专用的缓存装置来取代普通节点作为转发节点,并改变了普通节点的分配方式和Ferry节点的交互方式。最后,通过数学计算和数学分析表明MRT-Star在不额外消耗普通节点的缓存和能量的同时,还能获得比MRT-Tree较低的数据传输延迟。 展开更多
关键词 延迟容忍网络 数据传输延迟 ferry路由设计 树型拓扑 星型拓扑
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机会网络中基于城乡模型的多ferry路由设计
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作者 李云 翁斌斌 +1 位作者 刘期烈 唐丽均 《计算机应用研究》 CSCD 北大核心 2012年第1期263-265,共3页
为更贴近机会网络的实际应用,提出了城乡模型。基于此模型,为了降低网络的平均传输时延,提出了DF(direct-ferry)算法。DF算法是通过调度所有ferry的运动来实现ferry之间的直接通信,从而实现网络的区间通信。通过DF算法和使用中继节点的f... 为更贴近机会网络的实际应用,提出了城乡模型。基于此模型,为了降低网络的平均传输时延,提出了DF(direct-ferry)算法。DF算法是通过调度所有ferry的运动来实现ferry之间的直接通信,从而实现网络的区间通信。通过DF算法和使用中继节点的ferry路由算法的对比,得出DF算法能够有效降低网络的平均传输时延。 展开更多
关键词 机会网络 城乡模型 路由 ferry 平均传输时延
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基于多约束条件的Ferry路由机制的研究
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作者 刘家康 彭娟 薛丽琴 《北京理工大学学报》 EI CAS CSCD 北大核心 2013年第8期836-840,共5页
针对偏远乡村网络的问题,结合Message Ferry机制,提出了基于多约束条件的Ferry路由机制(MCFR).该机制充分利用Ferry中所携带的数据包信息和节点位置信息计算Ferry到各个节点的评估值,通过评估值选择Ferry的下一跳.仿真结果表明,相对于... 针对偏远乡村网络的问题,结合Message Ferry机制,提出了基于多约束条件的Ferry路由机制(MCFR).该机制充分利用Ferry中所携带的数据包信息和节点位置信息计算Ferry到各个节点的评估值,通过评估值选择Ferry的下一跳.仿真结果表明,相对于消息摆渡路由机制(MFR),该路由机制能够提高投递率,并减小端到端时延. 展开更多
关键词 容迟网络 MESSAGE ferry机制 多约束 网络仿真
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基于FerryBox的渤海海峡水质低成本长期自动监测 被引量:3
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作者 侯朝伟 唐诚 +2 位作者 邹涛 刘欣 张华 《海洋科学》 CAS CSCD 北大核心 2017年第5期59-70,共12页
FerryBox是一套全自动、实时的水生生态监测系统,具有多参数、低维护、低成本、监测覆盖范围广、可持续性强等诸多优点。2015年10月~2016年7月,作者通过将其安装在一条频繁返于烟台-大连之间的货船上,实现了10个月的渤海海峡水质低成本... FerryBox是一套全自动、实时的水生生态监测系统,具有多参数、低维护、低成本、监测覆盖范围广、可持续性强等诸多优点。2015年10月~2016年7月,作者通过将其安装在一条频繁返于烟台-大连之间的货船上,实现了10个月的渤海海峡水质低成本长期自动监测。监测结果表明,渤海海峡水环境因子在时空分布上存在显著的南北差异,秋季海峡南部海域的表层浊度及pH均高于中部及北部海域;冬季海峡北部海域的表层温度、盐度和浊度均大于南部海域;进入春季以后海峡中南部海域为表层叶绿素a浓度高值区。季风、黄海暖流以及渤海环流等因素是造成渤海海峡水环境因子南北差异的主要原因。春、夏季渤海海峡营养盐监测结果表明,渤海海峡营养盐的时空分布具有明显的季节性和区域性特征,在时间变化上整体呈现初春和夏末较高,在空间分布上整体呈现海峡两侧高于海峡中部。海底冷水团颗粒物的分解、藻类繁殖、地表径流以及渤海环流等,是影响渤海海峡春、夏季营养盐时空分布的重要因素。春季渤海海峡浮游生物生长受硅和磷的双重限制,夏季主要受磷限制。 展开更多
关键词 ferry BOX 渤海海峡 水质 水环境因子 营养盐
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The Failure of Fast Ferry Catamaran Operations in New Zealand and Hawaii
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作者 Gui Lohmann Jakob Trischler 《Journal of Transportation Technologies》 2012年第2期102-112,共11页
Fast ferry catamarans have been in use for several decades. They possess the advantage of overcoming one of the major deficiencies of water transportation: low speed. Although their operation has spread throughout dif... Fast ferry catamarans have been in use for several decades. They possess the advantage of overcoming one of the major deficiencies of water transportation: low speed. Although their operation has spread throughout different parts of the world, an overall analysis of the implementation and failures of this technology remains underdeveloped in the transport literature. This paper presents and compares two unsuccessful experiences of the use of fast ferry catamarans in New Zealand and Hawaii. Although both attempts possess major differences in terms of their contexts, particularly regarding competition, regulatory and environmental issues, some of the common lessons learned from both experiences can significantly contribute to a better understanding of this water transport technology and the challenges involved in its operation. 展开更多
关键词 Fast ferry CATAMARAN Technology COOK STRAIT FERRIES New Zealand Hawaii Superferry
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Open-Type Ferry Safety System Design for Using LNG Fuel 被引量:2
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作者 D. N. Pagonis G. Livanos G. Theotokatos 《Journal of Marine Science and Application》 CSCD 2016年第4期405-425,共21页
In this feasibility study, we investigate the viability of using Liquefied Natural Gas (LNG) fuel in an open type Ro-Ro passenger ferry and the associated potential challenges with regard to the vessel safety system... In this feasibility study, we investigate the viability of using Liquefied Natural Gas (LNG) fuel in an open type Ro-Ro passenger ferry and the associated potential challenges with regard to the vessel safety systems. We recommend an appropriate methodology for converting existing ships to run on LNG fuel, discuss all the necessary modifications to the ship’s safety systems, and also evaluate the relevant ship evacuation procedures. We outline the basic requirements with which the ship already complies for each safety system and analyze the additional restrictions that must be taken into consideration for the use of LNG fuel. Appropriate actions are recommended. Furthermore, we carry out a hazard identification study. Overall, we clearly demonstrate the technical feasibility of the investigated scenario. Minimal modifications to the ship’s safety systems are required to comply with existing safety rules for this specific type of ship. 展开更多
关键词 LNG fuel fuel conversion ship safety systems LNG regulations open-type ferry design study
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Energy-constrained ferry route design for sparse wireless sensor networks 被引量:2
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作者 王勇 彭伟 +1 位作者 窦强 龚正虎 《Journal of Central South University》 SCIE EI CAS 2013年第11期3142-3149,共8页
In recent years,using message ferries as mechanical carriers of data has been shown to be an effective way to collect information in sparse wireless sensor networks.As the sensors are far away from each other in such ... In recent years,using message ferries as mechanical carriers of data has been shown to be an effective way to collect information in sparse wireless sensor networks.As the sensors are far away from each other in such highly partitioned scenario,a message ferry needs to travel a long route to access all the sensors and carry the data collected from the sensors to the sink.Typically,practical constraints(e.g.,the energy)preclude a ferry from visiting all sensors in a single tour.In such case,the ferry can only access part of the sensors in each tour and move back to the sink to get the energy refilled.So,the energy-constrained ferry route design(ECFRD)problem is discussed,which leads to the optimization problem of minimizing the total route length of the ferry,while keeping the route length of each tour below a given constraint.The ECFRD problem is proved to be NP-hard problem,and the integer linear programming(ILP)formulation is given.After that,efficient heuristic algorithms are proposed to solve this problem.The experimental results show that the performances of the proposed algorithms are effective in practice compared to the optimal solution. 展开更多
关键词 message ferry energy-constrained route design integer linear programming wireless sensor networks
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Assessing Safety of Ferry Routes by Ship Handling Model through AHP and Fuzzy Approach 被引量:3
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作者 Antoni Arif Priadi Tri Tjahjono Abdellatif Benabdelhafid 《Intelligent Information Management》 2012年第5期277-283,共7页
Ferry accidents often occur the result of ship handling difficulty which interfacing human, machine and environment. Therefore, a decision tool model as a comprehensive information system, based on the ship handling d... Ferry accidents often occur the result of ship handling difficulty which interfacing human, machine and environment. Therefore, a decision tool model as a comprehensive information system, based on the ship handling difficulty, needs to be developed through the combination of Analytic Hierarchy Process (AHP) and Fuzzy Logic System. The Fuzzy Logic System part consists of ship condition, ship handling facility condition, navigation condition and weather condition. The output of decision tool is the ship handling difficulty level in linguistic form. The simulation of model is conducted at several straits in Indonesia water. The decision tool model could be used as management information system by port authority to monitor the ferry/ship movement in real time regarding the ship handling difficulty. Further, it would be used to take some useful safety operation strategies and safety policies to improve ferry transportation safety at port water and strait water. 展开更多
关键词 Ro-Ro ferry AHP FUZZY SHIP HANDLING
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Optimism in Crossing Brookly Ferry
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作者 安莉 《陕西师范大学学报(哲学社会科学版)》 CSSCI 北大核心 2004年第S2期438-440,共3页
Crossing Brookly Ferry is one of the most representative masterpieces composed by Walt Wiltman. In this pieces of writing, ones of the characteristics in this poem: optimism and unconventionality in its form are expre... Crossing Brookly Ferry is one of the most representative masterpieces composed by Walt Wiltman. In this pieces of writing, ones of the characteristics in this poem: optimism and unconventionality in its form are expressed in details. 展开更多
关键词 CROSSING Brookly ferry AMERICAN LITERATURE OPTIMISM
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Admiration and Doubt—Comparing Crossing Brooklyn Ferry and To Brooklyn Bridge
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作者 CAI Yi-lun JIA Xiao-yun 《Sino-US English Teaching》 2019年第6期256-259,共4页
American poet, Walt Whitman and Harold Hart Crane both write poems about the place connecting Brooklyn and Manhattan, in Crossing Brooklyn Ferry and To Brooklyn Bridge respectively. By comparing the similarities of th... American poet, Walt Whitman and Harold Hart Crane both write poems about the place connecting Brooklyn and Manhattan, in Crossing Brooklyn Ferry and To Brooklyn Bridge respectively. By comparing the similarities of these two poems, this paper analyses the two poets’ attitudes towards the development of modern society, finding that both poets not only show admiration for modern society but also doubt about the fast development. It aims to reveal the influence of fast development of modern society on people’s mentality. 展开更多
关键词 CROSSING Brooklyn ferry To Brooklyn BRIDGE ADMIRATION DOUBT
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On the Embodiment of Chinese Classical Thought in Whitman's Urban Ecological Poetics——Taking the Riverbank of the Ferry Crossing Last Winter as an Example
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作者 Feiyun Wang 《Journal of Contemporary Educational Research》 2020年第6期69-70,共2页
Whitman believes that people in cities should establish a harmonious relationship between humans and nature.In his urban imagination,humans are a common link in the entire ecosystem.As a part of heaven and earth,every... Whitman believes that people in cities should establish a harmonious relationship between humans and nature.In his urban imagination,humans are a common link in the entire ecosystem.As a part of heaven and earth,everything is one.Through dialogue with nature,Whitman explored that man and nature should be equal and harmonious.Whitman embodies the unique urban ecological poetics in his essay the Riverbank of the Ferry Crossing Last Winter,which contains Chinese classical thought of harmony between man and nature. 展开更多
关键词 WHITMAN The Riverbank of the ferry Crossing Last Winter Chinese classical thought The relationship between humans and nature
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The Channel Characteristics Analysis of Two River Types in Lee's Ferry Area
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作者 Feng Moyang David Elliot Wang Lu 《Meteorological and Environmental Research》 CAS 2016年第2期52-54,57,共4页
Discovery showed that some of the rivers in Lee's Ferry area run on bedrocks while some are on the alluvium,based on geomorphology,the different kinds of channel characteristics can influence whether these rivers run... Discovery showed that some of the rivers in Lee's Ferry area run on bedrocks while some are on the alluvium,based on geomorphology,the different kinds of channel characteristics can influence whether these rivers run on bed rock or alluvium. By analyzing the velocity,discharge,width and depth,hydraulic radius and comparing the different channel characteristics of rivers in other areas with Lee's Ferry,it is observed that the channel discharge,velocity and the hydraulic radius play an important role in controlling the transport-limited river and these factors can be inferred to be correct even for all the river channels in Arizona. 展开更多
关键词 Channel characteristic Lee's ferry Controlling factor
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Assessment of Investment Risk in Greek Short Sea Shipping: A Ro-Ro Passenger Ferry Case
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作者 Dimitrios V. Lyridis Panayotis G. Zacharioudakis 《Journal of Shipping and Ocean Engineering》 2012年第1期36-44,共9页
The purpose of this paper is to introduce an innovative methodology in shipping investment evaluation based on simulation of a project cash flow. It concerns a complementary approach to current practices and its aim i... The purpose of this paper is to introduce an innovative methodology in shipping investment evaluation based on simulation of a project cash flow. It concerns a complementary approach to current practices and its aim is to provide more information mainly to ship-owners that consider the feasibility of deploying Ro-Ro Passenger ferries. The paper examines a typical semi-conventional RoPax ferry operating in the Aegean Sea. It addresses important economic, operational and procedural issues concerning risk evaluation. The current status is that risk is a notion still strange to main stakeholders. The Greek practice in performing a feasibility study for a project draws on investor's experience and feeling aided by a preliminary economic study. The main thesis of this paper is that there are alternative techniques to evaluate investment risk and measure profitability of a project. A Monte Carlo simulation in collaboration with a typical Ro-Ro cash-flow model is implemented to reveal the extent of risk and provide a useful tool for the assessment of future investments in Greek Short Sea Shipping. 展开更多
关键词 Greek Short Sea Shipping investment risk passenger ferries Ro-Ro feasibility study.
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基于F-J-M法的桥梁温度与地震作用效应组合研究
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作者 王力 潘启仁 +2 位作者 周晓夫 杨喜娟 唐智勇 《防灾减灾工程学报》 CSCD 北大核心 2024年第2期273-282,共10页
目前铁路桥梁设计逐渐由容许应力法向极限状态法转变,而《铁路桥涵设计规范(极限状态法)》(Q/CR 9300—2018)并未提及地震作用与温度等可变作用的联合作用,给高寒高烈度区桥梁结构抗震设计带来了较大困难。为了推进桥梁以更经济的抗力... 目前铁路桥梁设计逐渐由容许应力法向极限状态法转变,而《铁路桥涵设计规范(极限状态法)》(Q/CR 9300—2018)并未提及地震作用与温度等可变作用的联合作用,给高寒高烈度区桥梁结构抗震设计带来了较大困难。为了推进桥梁以更经济的抗力方式抵御外荷载作用,通过目标可靠度指标确定其最优地震设计状况荷载组合分项系数,从而对现行桥梁设计规范抗震设计进行优化。建立了高寒地区某桥温度作用效应概率模型,使用Ferry Borges荷载组合理论探究地震和环境温度作用的效应分布特征,并基于JC法和多灾害荷载系数设计法(MH-LRFD)建立地震、温度作用荷载系数的表达式。依托某桥梁工程实例分别探究了地震、温度以及两者共同作用下的桥梁的失效概率。研究结果表明:环境温度引起的桥梁温度内力响应、主要构件材料特性变异均能显著影响桥梁的失效概率;对于高寒大温差地区,现行规范忽略环境温度效应将显著低估桥梁在地震作用下的失效概率。本文提出的F-J-M(Ferry Borges+JC+MH-LRFD)方法计算地震、温度作用组合系数,可为高寒地区桥梁抗震设计提供必要理论依据。 展开更多
关键词 温度效应概率模型 失效概率 ferry Bordge法 MH-LRFD 荷载系数
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The Ferry Cover Problem on Regular Graphs and Small-Degree Graphs
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作者 Erfang SHAN Liying KANG 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2018年第6期933-946,共14页
The ferry problem may be viewed as generalizations of the classical wolf-goatcabbage puzzle. The ferry cover problem is to determine the minimum required boat capacity to safely transport n items represented by a conf... The ferry problem may be viewed as generalizations of the classical wolf-goatcabbage puzzle. The ferry cover problem is to determine the minimum required boat capacity to safely transport n items represented by a conflict graph. The Alcuin number of a conflict graph is the smallest capacity of a boat for which the graph possesses a feasible ferry schedule. In this paper the authors determine the Alcuin number of regular graphs and graphs with maximum degree at most five. 展开更多
关键词 Graph Alcuin number ferry problem Vertex cover Regular graph
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地震和重卡车荷载作用下桥梁多灾害设计理论研究 被引量:4
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作者 孙得璋 《国际地震动态》 2013年第6期42-43,共2页
现在(美国)桥梁的设计(包括LRFD)多是针对单个极端荷载,而极端荷载种类和频率的增加使桥梁在设计期内遭受其他极端荷载情况时,很有可能会对桥梁以及人员造成很大的损失。因此,迫切需要对桥梁进行多灾害研究和设计。本文正是基于LRF... 现在(美国)桥梁的设计(包括LRFD)多是针对单个极端荷载,而极端荷载种类和频率的增加使桥梁在设计期内遭受其他极端荷载情况时,很有可能会对桥梁以及人员造成很大的损失。因此,迫切需要对桥梁进行多灾害研究和设计。本文正是基于LRFD桥梁设计的形式,并作为MH-LRFD研究的一部分,主要研究在地震作用、重卡车荷载等极端荷载作用下, 展开更多
关键词 多灾害 LRFD 极限状态 失效模式 ferry Borges-Castanheta模型 荷载系数 PUSHOVER分析
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我国首条750kV线路与美国新型765kV线路的比较
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作者 何大愚 《电网技术》 EI CSCD 北大核心 2006年第20期6-9,13,共5页
简要介绍并对比了我国西北电网的第一条750kV官亭—兰州东输电线路和即将建成的美国AEP新型765kVWyoming-JacksonsFerry输电线路。认为两者具有相同的运行电压等级和相近的输电距离,并均以结构方面的创新(新型分裂导线和新型杆搭设计)... 简要介绍并对比了我国西北电网的第一条750kV官亭—兰州东输电线路和即将建成的美国AEP新型765kVWyoming-JacksonsFerry输电线路。认为两者具有相同的运行电压等级和相近的输电距离,并均以结构方面的创新(新型分裂导线和新型杆搭设计)达到了输电建设工程的世界先进技术水平。而我国输电建设的社会条件更优越,应借此努力推进EHV和UHV的既定工程项目,以消除发电和输电之间的发展差距。 展开更多
关键词 750KV输电 官亭-兰州东线路 765kV输电 Wyoming-Jacksons ferry线路 输电建设 电力系统
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基于最小支配集组簇的MF路由协议 被引量:1
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作者 吴柏君 林锋 周激流 《计算机工程》 CAS CSCD 北大核心 2010年第4期99-102,共4页
为了进一步提高容延迟移动传感器网络中的数据投递率、降低平均延迟和能量消耗,提出一种改进的Message Ferry(MF)路由协议MF-MDS。该协议采用最小支配集对网络中的普通节点进行组簇。在NS-2上进行的仿真实验证明MF-MDS在投递率和平均延... 为了进一步提高容延迟移动传感器网络中的数据投递率、降低平均延迟和能量消耗,提出一种改进的Message Ferry(MF)路由协议MF-MDS。该协议采用最小支配集对网络中的普通节点进行组簇。在NS-2上进行的仿真实验证明MF-MDS在投递率和平均延迟上明显优于传统的MF协议。 展开更多
关键词 容延迟移动传感器网络 MESSAGE ferry路由协议 最小支配集
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