In some real complex networks, only a few nodes can obtain the global information about the entire networks, but most of the nodes own only local connections therefore own only local information of the networks. A new...In some real complex networks, only a few nodes can obtain the global information about the entire networks, but most of the nodes own only local connections therefore own only local information of the networks. A new local-world evolving network model is proposed in this paper. In the model, not all the nodes obtain local network information, which is different from the local world network model proposed by Li and Chen （LC model）. In the LC model, each node has only the local connections therefore owns only local information about the entire networks. Theoretical analysis and numerical simulation show that adjusting the ratio of the number of nodes obtaining the global information of the network to the total number of nodes can effectively control the valuing range for the power-law exponent of the new network. Therefore, if the topological structure of a complex network, especially its exponent of power-law degree distribution, needs controlling, we just add or take away a few nodes which own the global information of the network.展开更多
In view of the serious reactive power loss in the rural network, improved ant colony optimization algorithm （ACOA） was used to optimize the reactive power compensation for the rural distribution system. In this stud...In view of the serious reactive power loss in the rural network, improved ant colony optimization algorithm （ACOA） was used to optimize the reactive power compensation for the rural distribution system. In this study, the traditional ACOA was improved in two aspects： one was the local search strategy, and the other was pheromone mutation and re-initialization strategies. The reactive power optimization for a county＇s distribution network showed that the improved ACOA was practicable.展开更多
随着新能源技术的发展和普及,大量非线性用电设备接入电网对其电能质量产生了严重影响。为解决谐波扰动信号对电力系统带来的影响,提出将改进的局部均值分解LMD(local mean decomposition)和概率神经网络相结合,构造一种电压扰动分类器...随着新能源技术的发展和普及,大量非线性用电设备接入电网对其电能质量产生了严重影响。为解决谐波扰动信号对电力系统带来的影响,提出将改进的局部均值分解LMD(local mean decomposition)和概率神经网络相结合,构造一种电压扰动分类器,对电力系统中的电压扰动信号进行识别分类。通过构造三角波形自适应地延拓扰动信号的方法抑制LMD的端点效应,应用改进LMD算法对扰动信号进行3层分解,得到具有电压信号幅频信息的乘积函数PF(product function)分量,将由PF分量构造的信号能量作为概率神经网络的输入,以识别和分类电压干扰信号。通过建立训练模型对电压扰动信号进行仿真实验,结果表明,该方法可以准确识别电压扰动信号,有助于提高电力系统中电压扰动信号的识别精度。展开更多
为提高电力线局域网通信的可靠性与稳定性,引进离散贝叶斯网络,以某电力线局域网为例,开展通信节点故障定位方法的设计。设定不同节点在通信过程中的参数具体取值,掌握是否有节点在通信中存在异常,根据用户的通信需求,进行电力线局域网...为提高电力线局域网通信的可靠性与稳定性,引进离散贝叶斯网络,以某电力线局域网为例,开展通信节点故障定位方法的设计。设定不同节点在通信过程中的参数具体取值,掌握是否有节点在通信中存在异常,根据用户的通信需求,进行电力线局域网通信分割粒度、不同节点在通信过程中风险指数、网节点与故障形式匹配度的计算,实现节点故障特征参数的提取;引进离散贝叶斯网络,提取节点的随机变量集合,建立针对节点故障离散数据的故障诊断模型,计算节点可能出现故障的概率;保留概率值较高的节点,将其与离散贝叶斯网络中的离散节点进行匹配,完成匹配后按照故障概率值的大小输出节点,实现电力线局域网(Local Area Network,LAN)通信节点故障辨识与自动定位。实验结果证明:该方法不仅可以实现对电力线局域网通信节点故障的定位,还可以缩短定位时长,实现对电力线局域网通信过程中节点故障的快速感知。展开更多
A hybrid methodology is proposed for use in low power, safety critical wireless sensor network applications, where quality-of-service orientated transceiver output power control is required to operate in parallel with...A hybrid methodology is proposed for use in low power, safety critical wireless sensor network applications, where quality-of-service orientated transceiver output power control is required to operate in parallel with radio frequency-based localization. The practical implementation is framed in an experimental procedure designed to track a moving agent in a realistic indoor environment. An adaptive time synchronized approach is employed to ensure the positioning technique can operate effectively in the presence of dataloss and where the transmitter output power of the mobile agent is varying due to power control. A deterministic multilateration-based positioning approach is adopted and accuracy is improved by filtering signal strength measurements overtime to account for multipath fading. The location estimate is arrived at by employing least-squares estimation. Power control is implemented at two separate levels in the network topology. First, power control is applied to the uplink between the tracking reference nodes and the centralized access point. A number of algorithms are implemented highlighting the advantage associated with using additional feedback bandwidth, where available, and also the need for effective time delay compensation. The second layer of power control is implemented on the uplink between the mobile agent and the access point and here quantifiable improvements in quality of service and energy efficiency are observed. The hybrid paradigm is extensively tested experimentally on a fully compliant 802.15.4 testbed, where mobility is considered in the problem formulation using a team of fully autonomous robots.展开更多
区块链技术作为一种新颖的数据结构组织形式,在能源互联网领域的应用研究已经逐渐兴起,并崭露头角。区块链技术去中心化、智能合约、协同自治等特质,吻合了能源局域网(energy local network,ELN)自动需求响应(automatic demand response...区块链技术作为一种新颖的数据结构组织形式,在能源互联网领域的应用研究已经逐渐兴起,并崭露头角。区块链技术去中心化、智能合约、协同自治等特质,吻合了能源局域网(energy local network,ELN)自动需求响应(automatic demand response,ADR)项目的诉求,为此基于区块链技术提出ELN储能系统的ADR方法,探索区块链技术在能源领域的有益应用模式。研究了区块链视角下的ELN表征形式;借鉴拥塞价格算法,发展了去中心化的ADR准则,响应主体能够依托该既定准则自主响应系统补偿需求;在此基础上,建立了响应主体间的智能合约,以保障能量交易与利益分配的高效执行。以某办公区域ELN为例进行了仿真分析,算例结果验证了所述ADR方法的合理性、有效性。展开更多
基金supported by the Scientific Research Starting Foundation of Hangzhou Dianzi University (Grant No KYS091507073)partly by the National High Technology Research and Development Program of China (Grant No 2005AA147030)
文摘In some real complex networks, only a few nodes can obtain the global information about the entire networks, but most of the nodes own only local connections therefore own only local information of the networks. A new local-world evolving network model is proposed in this paper. In the model, not all the nodes obtain local network information, which is different from the local world network model proposed by Li and Chen （LC model）. In the LC model, each node has only the local connections therefore owns only local information about the entire networks. Theoretical analysis and numerical simulation show that adjusting the ratio of the number of nodes obtaining the global information of the network to the total number of nodes can effectively control the valuing range for the power-law exponent of the new network. Therefore, if the topological structure of a complex network, especially its exponent of power-law degree distribution, needs controlling, we just add or take away a few nodes which own the global information of the network.
基金Supported by China Postdoctoral Science Foundation(20090460873)
文摘In view of the serious reactive power loss in the rural network, improved ant colony optimization algorithm （ACOA） was used to optimize the reactive power compensation for the rural distribution system. In this study, the traditional ACOA was improved in two aspects： one was the local search strategy, and the other was pheromone mutation and re-initialization strategies. The reactive power optimization for a county＇s distribution network showed that the improved ACOA was practicable.
文摘随着新能源技术的发展和普及,大量非线性用电设备接入电网对其电能质量产生了严重影响。为解决谐波扰动信号对电力系统带来的影响,提出将改进的局部均值分解LMD(local mean decomposition)和概率神经网络相结合,构造一种电压扰动分类器,对电力系统中的电压扰动信号进行识别分类。通过构造三角波形自适应地延拓扰动信号的方法抑制LMD的端点效应,应用改进LMD算法对扰动信号进行3层分解,得到具有电压信号幅频信息的乘积函数PF(product function)分量,将由PF分量构造的信号能量作为概率神经网络的输入,以识别和分类电压干扰信号。通过建立训练模型对电压扰动信号进行仿真实验,结果表明,该方法可以准确识别电压扰动信号,有助于提高电力系统中电压扰动信号的识别精度。
文摘为提高电力线局域网通信的可靠性与稳定性,引进离散贝叶斯网络,以某电力线局域网为例,开展通信节点故障定位方法的设计。设定不同节点在通信过程中的参数具体取值,掌握是否有节点在通信中存在异常,根据用户的通信需求,进行电力线局域网通信分割粒度、不同节点在通信过程中风险指数、网节点与故障形式匹配度的计算,实现节点故障特征参数的提取;引进离散贝叶斯网络,提取节点的随机变量集合,建立针对节点故障离散数据的故障诊断模型,计算节点可能出现故障的概率;保留概率值较高的节点,将其与离散贝叶斯网络中的离散节点进行匹配,完成匹配后按照故障概率值的大小输出节点,实现电力线局域网(Local Area Network,LAN)通信节点故障辨识与自动定位。实验结果证明:该方法不仅可以实现对电力线局域网通信节点故障的定位,还可以缩短定位时长,实现对电力线局域网通信过程中节点故障的快速感知。
基金Tyndall is a part of the CLARITY CSET supported by Science Foundation Ireland (No. 07/CE/I1147)
文摘A hybrid methodology is proposed for use in low power, safety critical wireless sensor network applications, where quality-of-service orientated transceiver output power control is required to operate in parallel with radio frequency-based localization. The practical implementation is framed in an experimental procedure designed to track a moving agent in a realistic indoor environment. An adaptive time synchronized approach is employed to ensure the positioning technique can operate effectively in the presence of dataloss and where the transmitter output power of the mobile agent is varying due to power control. A deterministic multilateration-based positioning approach is adopted and accuracy is improved by filtering signal strength measurements overtime to account for multipath fading. The location estimate is arrived at by employing least-squares estimation. Power control is implemented at two separate levels in the network topology. First, power control is applied to the uplink between the tracking reference nodes and the centralized access point. A number of algorithms are implemented highlighting the advantage associated with using additional feedback bandwidth, where available, and also the need for effective time delay compensation. The second layer of power control is implemented on the uplink between the mobile agent and the access point and here quantifiable improvements in quality of service and energy efficiency are observed. The hybrid paradigm is extensively tested experimentally on a fully compliant 802.15.4 testbed, where mobility is considered in the problem formulation using a team of fully autonomous robots.
文摘区块链技术作为一种新颖的数据结构组织形式,在能源互联网领域的应用研究已经逐渐兴起,并崭露头角。区块链技术去中心化、智能合约、协同自治等特质,吻合了能源局域网(energy local network,ELN)自动需求响应(automatic demand response,ADR)项目的诉求,为此基于区块链技术提出ELN储能系统的ADR方法,探索区块链技术在能源领域的有益应用模式。研究了区块链视角下的ELN表征形式;借鉴拥塞价格算法,发展了去中心化的ADR准则,响应主体能够依托该既定准则自主响应系统补偿需求;在此基础上,建立了响应主体间的智能合约,以保障能量交易与利益分配的高效执行。以某办公区域ELN为例进行了仿真分析,算例结果验证了所述ADR方法的合理性、有效性。
