检索结果-南通市图书馆

energy efficiency Analysis of Quadruped Robot with Trot Gait and Combined Cycloid Foot Trajectory

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2014年第1期27卷 138-145页

作者： LEI Jingtao WANG Feng YU Huangying WANG Tianmiao YUAN Peijiang School of Mechatronic Engineering and Automation Shanghai University School of Mechanical Engineering and Automation Beihang University

Quadruped robots consume a lot of energy, which is one of the factors restricting their application. energy efficiency is one of the key evaluating indicators for walking robots. The relationship between energy and elastic elements of walking robots have been studied, but different walking gait patterns and contact status have important influences on locomotion energy efficiency, and the energy efficiency considering the foot-end trajectory has not been reported. Therefore, the energy consumption and energy efficiency of quadruped robot with trot gait and combined cycloid foot trajectory are studied. The forward and inverse kinematics of quadruped robot is derived. The combined cycloid function is proposed to generate horizontal and vertical foot trajectory respectively, which can ensure the acceleration curve of the foot-end smoother and more successive, and reduce the contact force between feet and environment. Because of the variable topology mechanism characteristic of quadruped robot, the leg state is divided into three different phases which are swing phase, transition phase and stance phase during one trot gait cycle. The non-continuous variable constraint between feet and environment of quadruped robot is studied. The dynamic model of quadruped robot is derived considering the variable topology mechanism characteristic, the periodic contact and elastic elements of the robot. The total energy consumption of walking robot during one gait cycle is analyzed based on the dynamic model. The specific resistance is used to evaluate energy efficiency of quadruped robot. The calculation results show the relationships between specific resistance and gait parameters, which can be used to determine the reasonable gait parameters.

关键词： quadruped robot trot gait trajectory planning dynamic modeling energy efficiency

energy efficiency and area spectral efficiency tradeoff for coexisting wireless body sensor networks

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2016年第12期59卷 151-165页

作者： Ruixia LIU Yinglong WANG Shangbin WU Cheng-Xiang WANG Wensheng ZHANG College of Information Science and Engineering Shandong University of Science and Technology Shandong Provincial Key Laboratory of Computer Network Shandong Computer Science Center (National Supercomputer Center in Jinan) Institute of Sensors Signals and Systems School of Engineering and Physical Sciences Heriot-Watt University Shandong Provincial Key Laboratory of Wireless Communication Technologies School of Information Science and Engineering Shandong University

The coexistence of wireless body sensor networks(WBSNs) is a very challenging problem, due to strong interference, which seriously affects energy consumption and spectral reuse. The energy efficiency and spectral efficiency are two key performance evaluation metrics for wireless communication networks. In this paper, the fundamental tradeoff between energy efficiency and area spectral efficiency of WBSNs is first investigated under the Poisson point process(PPP) model and Matern hard-core point process(HCPP) model using stochastic geometry. The circuit power consumption is taken into consideration in energy efficiency calculation. The tradeoff judgement coefficient is developed and is shown to serve as a promising complementary measure. In addition, this paper proposes a new nearest neighbour distance power control strategy to improve energy efficiency. We show that there exists an optimal transmit power highly dependant on the density of WBSNs and the nearest neighbour distance. Some important properties are also addressed in the analysis of coexisting WBSNs based on the IEEE 802.15.4 standard, such as the impact of intensity nodes distribution,optimal guard zone, and outage probability. Simulation results show that the proposed power control design can reduce the outage probability and enhance energy efficiency. energy efficiency and area spectral efficiency of the HCPP model are better than those of the PPP model. In addition, the optimal density of WBSNs coexistence is obtained.

关键词： WBSNs coexistence stochastic geometry energy efficiency area spectral efficiency power control

energy efficiency aware dynamic rate and power adaptation in carrier sensing based WLANs under Rayleigh fading and shadowing

在线全文

学校读者我要写书评

暂无评论

Digital Communications and Networks 2024年第4期10卷 918-933页

作者： Forkan Uddin Department of Electrical and Electronic Engineering Bangladesh University of Engineering and TechnologyDhaka1205Bangladesh

We consider the problem of energy efficiency aware dynamic adaptation of data transmission rate and transmission power of the users in carrier sensing based Wireless Local Area Networks(WLANs)in the presence of path loss,Rayleigh fading and log-normal *** a data packet transmission,we formulate an optimization problem,solve the problem,and propose a rate and transmission power adaptation scheme with a restriction methodology of data packet transmission for achieving the optimal energy *** the restriction methodology of data packet transmission,a user does not transmit a data packet if the instantaneous channel gain of the user is lower than a *** evaluate the performance of the proposed scheme,we develop analytical models for computing the throughput and energy efficiency of WLANs under the proposed scheme considering a saturation traffic *** then validate the analytical models via *** find that the proposed scheme provides better throughput and energy efficiency with acceptable throughput fairness if the restriction methodology of data packet transmission is *** means of the analytical models and simulations,we demonstrate that the proposed scheme provides significantly higher throughput,energy efficiency and fairness index than a traditional non-adaptive scheme and an existing most relevant adaptive *** and energy efficiency gains obtained by the proposed scheme with respect to the existing adapting scheme are about 75%and 103%,respectively,for a fairness index of *** also study the effect of various system parameters on throughput and energy efficiency and provide various engineering insights.

关键词： Carrier sense multiple access energy efficiency Fading and shadowing Rate and power adaptation Throughput Wireless local area networks

energy efficiency Maximization for Cooperative NOMA with Hardware Impairments

在线全文

学校读者我要写书评

暂无评论

China Communications 2024年第12期21卷 80-91页

作者： Wang Zhengqiang Chang Ruifei Wan Xiaoyu Fan Zifu Duo Bin School of Communication and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China College of Computer Science and Cyber Security Chengdu University of TechnologyChengdu 610059China

The massive connectivity and limited energy pose significant challenges to deploy the enormous devices in energy-efficient and environmentally friendly in the Internet of Things(IoT).Motivated by these challenges,this paper investigates the energy efficiency(EE)maximization problem for downlink cooperative non-orthogonal multiple access(C-NOMA)systems with hardware impairments(HIs).The base station(BS)communicates with several users via a half-duplex(HD)amplified-and-forward(AF)***,we formulate the EE maximization problem of the system under HIs by jointly optimizing transmit power and power allocated coefficient(PAC)at BS,and transmit power at the *** original EE maximization problem is a non-convex problem,which is challenging to give the optimal solution ***,we use fractional programming to convert the EE maximization problem as a series of subtraction form ***,variable substitution and block coordinate descent(BCD)method are used to handle the ***,a resource allocation algorithm is proposed to maximize the EE of the ***,simulation results show that the proposed algorithm outperforms the downlink cooperative orthogonal multiple access(C-OMA)scheme.

关键词： block coordinate descent cooperative non-orthogonal multiple access energy efficiency hardware impairments resource allocation

energy efficiency in ARQ-Based Multi-Hop Systems and the Tradeoff with Throughput

在线全文

学校读者我要写书评

暂无评论

China Communications 2023年第6期20卷 60-71页

作者： Ali Asghar Haghighi Electrical and Computer Engineering Group Golpayegan College of EngineeringIsfahan University of TechnologyGolpayegan 87717-67498Iran

The minimum energy per bit(EPB)as the energy efficiency(EE)metric in an automatic retransmission request(ARQ)based multi-hop system is analyzed under power and throughput *** ARQ protocols including type-I(ARQ-I)and repetition redundancy(ARQ-RR)are considered and expressions for the optimal power allocation(PA)are *** the obtained optimal powers,the EE-throughput tradeoff(EETT)is analyzed and the EETT closed-form expressions for both ARQ protocols and in arbitrary average channel gain values are *** is shown that how different throughput requirements,especially the high levels,affect the EE ***,asymptotic analysis is made in the feasible high throughput values and lower and upper EETT bounds are derived for ARQ-I *** evaluate the EE a distributed PA scenario,as a benchmark,is presented and the energy savinggain obtained from the optimal PA in comparison with the distributed PA for ARQ-I and ARQ-RR protocols is discussed in different throughput values and node locations.

关键词： ARQ cooperative relaying energy efficiency green communication multi-hop systems routing algorithms throughput analysis

energy efficiency of massive MIMO wireless communication systems with antenna selection

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2014年第6期21卷 1-8页

作者： HU Bi-bo LIU Yuan-an XIE Gang GAO Jin-chun YANG Ya-lin School of Electronic Engineering Beijing University of Posts and Telecommunications School of Information and Communication Engineering Beijing University of Posts and Telecommunications

Massive multiple-input multiple-output（MIMO） requires a large number（tens or hundreds） of base station antennas serving for much smaller number of terminals, with large gains in energy efficiency and spectral efficiency compared with traditional MIMO technology. Large scale antennas mean large scale radio frequency（RF） chains. Considering the plenty of power consumption and high cost of RF chains, antenna selection is necessary for Massive MIMO wireless communication systems in both transmitting end and receiving end. An energy efficient antenna selection algorithm based on convex optimization was proposed for Massive MIMO wireless communication systems. On the condition that the channel capacity of the cell is larger than a certain threshold, the number of transmit antenna, the subset of transmit antenna and servable mobile terminals（MTs） were jointly optimized to maximize energy efficiency. The joint optimization problem was proved in detail. The proposed algorithm is verified by analysis and numerical simulations. Good performance gain of energy efficiency is obtained comparing with no antenna selection.

关键词： energy efficiency massive MIMO wireless communication systems antenna selection joint optimization

energy efficiency-Based Decision Making in Cognitive Radio Networks

在线全文

学校读者我要写书评

暂无评论

China Communications 2016年第11期13卷 205-213页

作者： Hongning Li Qingqi Pei Leilei Xu State Key Laboratory of Integrated Services Networks Xidian University School of Telecommunications Engineering Xidian University

As a constraint for smart devices,energy consumption has attract people's attention for a long time period. How to get higher resource utilization with less energy consumption is a challenge for cognitive radio networks. Secondary users have to participate in spectrum sensing at the cost of energy and access idle spectrum without interfering primary users. However,not all participating secondary users can access idle spectrum. How to ensure the participation users access spectrum efficiently with a larger probability is an urgent problem to be solved. We propose an energy efficiency-based Decision Making(EEDM) for cognitive radio networks,which fully considers residual energy and probability of obtaining spectrum resources. Simulation and analysis show that the proposed scheme can maximize proportion of allocated users under the premise of ensuring the accuracy of spectrum sensing,then balance users' energy consumption and access efficiency,so as to effectively improve the utilization of spectrum resources.

关键词： cognitive radio networks spectrum sensing energy efficiency decision making

energy efficiency Analysis of Multi-Antenna Cellular Networks with Strategic Sleep Relay

在线全文

学校读者我要写书评

暂无评论

China Communications 2018年第9期15卷 136-146页

作者： Yonghong Chen Jie Yang Xuehong Cao Shibing Zhang Department of Communication and Information Engineering Nanjing University of Posts and Telecommunications Xinglin College Nantong University Department of Communication Engineering Nanjing Institute of Technology School of Electronics and Information Nantong University

energy efficiency(EE) of cellular networks has attracted considerable attention recently. However, EE of relay-assisted cellular networks where the macro base stations(MBSs) are equipped with the multi-antenna has not been thoroughly addressed. This paper considered the downlink transmission of multi-antenna relay-assisted cellular networks, meanwhile, a strategic sleep scheme was used in relay stations(RSs), which dynamically adjusted the RS working mode according to whether the number of users serviced by the relay exceeds a given threshold. A geometric model was built to derive the coverage probability and mean achievable rate from the MBSs to user(UE), the MBS to RS, the RS to UE links and analyze the system EE. It is shown that the energy efficiency of cellular network with strategic sleep RS is slightly higher than that of cellular network with non-sleeping strategy. Furthermore, the MBS equipped with multi-antenna has better impact on energy efficiency and spectral efficiency than the MBS with single antenna.

关键词： energy efficiency coverage probability strategic sleep multi-antenna meana chievable rate

energy efficiency Maximization Strategy for Sink Node in SWIPT-Enabled Sensor-Cloud Based on Optimal Stopping Rules

在线全文

学校读者我要写书评

暂无评论

China Communications 2021年第1期18卷 222-236页

作者： Zhe Wang Lina Ge Taoshen Li Guifen Zhang Min Wu Institute of Artificial Intelligence Guangxi University for NationalitiesNanning 530004China Guangxi Key Laboratory of Hybrid Computation and IC Design Analysis Nanning 530006China School of Computer Electronics and InformationGuangxi UniversityNanning 530006China Guangxi Power Grid Co. LtdNanning 530023China

Leveraging energy harvesting abilities in wireless network devices has emerged as an effective way to prolong the lifetime of energy constrained *** system gains are usually optimized by designing resource allocation algorithm ***,few works focus on the interaction that channel’s time-vary characters make the energy transfer *** address this,we propose a novel system operation sequence for sensor-cloud system where the Sinks provide SWIPT for sensor nodes opportunistically during downlink phase and collect the data transmitted from sensor nodes in uplink ***,the energy-efficiency maximization problem of the Sinks is presented by considering the time costs and energy consumption of channel *** is proved that the formulated problem is an optimal stopping process with optimal stopping *** optimal energy-efficiency(OEE)algorithm is designed to obtain the optimal stopping rules for ***,the simulations are performed based on the OEE algorithm compared with the other two strategies to verify the effectiveness and gains in improving the system efficiency.

关键词： sensor-cloud SWIPT optimal stopping theory energy efficiency channel quality