(EERSM): Energy-Efficient Multi-Hop Routing Technique in Wireless Sensor Networks Based on Combination between Stationary and Mobile Nodes

In Wireless Sensor Network (WSNs), sensor nodes collect data and send them to a Base Station (BS) for further processing. One of the most issues in WSNs that researchers have proposed a hundred of technique to solve its impact is the energy constraint since sensor nodes have small battery, small memory and less data processing with low computational capabilities. However, many researches efforts have focused on how to prolong the battery lifetime of sensor nodes by proposing different routing, MAC, localization, data aggregation, topology construction techniques. In this paper, we will focus on routing techniques which aim to prolonging the network lifetime. Hence, we propose an Energy-Efficient Routing technique in WSNs based on Stationary and Mobile nodes (EERSM). Sensing filed is divided into intersected circles which contain Mobile Nodes (MN). The proposed data aggregation technique via the circular topology will eliminate the redundant data to be sent to the Base Station (BS). MN in each circle will rout packets for their source nodes, and move to the intersected area where another MN is waiting (sleep mode) to receive the transmitted packet, and then the packet will be delivered to the next intersected area until the packet is arrived to the BS. Our proposed EERSM technique is simulated using MATLAB and compared with conventional multi-hop techniques under different network models and scenarios. In the simulation, we will show how the proposed EERSM technique overcomes many routing protocols in terms of the number of hops counted when sending packets from a source node to the destination (i.e. BS), the average residual energy, number of sent packets to the BS, and the number of a live sensor nodes verse the simulation rounds.

MULTI-HOP RELAYING IN 5G： FROM RESEARCH TO SYSTEMS, STANDARDS, AND APPLICATIONS

In recent years,the demands of high traffic transmission motivate the rapid development of wireless access techniques,and it becomes promising to design the fifth generation(5G)wireless networks.Essential requirements for 5G involve higher traffic volume,indoor or hotspot traffic,and spectrum,energy,and cost efficien-

Multiway Relay Based Framework for Network Coding in Multi-Hop WSNs

In today’s information technology(IT)world,the multi-hop wireless sensor networks(MHWSNs)are considered the building block for the Internet of Things(IoT)enabled communication systems for controlling everyday tasks of organizations and industry to provide quality of service(QoS)in a stipulated time slot to end-user over the Internet.Smart city(SC)is an example of one such application which can automate a group of civil services like automatic control of traffic lights,weather prediction,surveillance,etc.,in our daily life.These IoT-based networks with multi-hop communication and multiple sink nodes provide efficient communication in terms of performance parameters such as throughput,energy efficiency,and end-to-end delay,wherein low latency is considered a challenging issue in next-generation networks(NGN).This paper introduces a single and parallels stable server queuing model with amulti-class of packets and native and coded packet flowto illustrate the simple chain topology and complexmultiway relay(MWR)node with specific neighbor topology.Further,for improving data transmission capacity inMHWSNs,an analytical framework for packet transmission using network coding at the MWR node in the network layer with opportunistic listening is performed by considering bi-directional network flow at the MWR node.Finally,the accuracy of the proposed multi-server multi-class queuing model is evaluated with and without network coding at the network layer by transmitting data packets.The results of the proposed analytical framework are validated and proved effective by comparing these analytical results to simulation results.

Fault Waveform Regenerator and Its Digital Closed-Loop Modification Technique

In order to provide a novel and more effective alternative to the commonly used relay protection testing device that outputs only the sinusoidal testing signals, the concept of fault waveform regenerator is proposed in this paper, together with its hardware structure and software flow chart. Fault waveform regenerator mainly depends on its power amplifiers (PAs) to regenerate the fault waveforms recorded by digital fault recorder (DFR). To counteract the PA’s inherent nonlinear distortions, a digital closed-loop modification technique that is different from the predistortion technique is conceived. And the experimental results verify the effectiveness of the fault waveform regenerator based on the digital closed-loop modification technique.

Outage Probability Based on Relay Selection Method for Multi-Hop Device-to-Device Communication

To improve the connectivity of device-to-device(D2D)communication between delay-assisted vehicles,a multi-hop D2D relay selection strategy based on outage probability is proposed.The algorithm firstly clusters the relay users based on the distance of D2D users,and determines the number of one-hop relay nodes through the outage probability threshold.Two-hop relay nodes directly select the same number of relays as one-hop relay nodes according to the descending order of signal noise ratio(SNR)to establish a square matrix.The Hungarian algorithm is used to assign the relay nodes of two clusters to complete the inter relay communication.Finally,the information is sent to the D2D receiver by combining technology.The simulation results show that this algorithm can reduce the cost of relay probing process and the outage probability of system in multi-hop D2D relay communication.

Secure Wireless Multicasting through Nakagami-m Fading Channels with Multi-Hop Relaying

The additional diversity gain provided by the relays improves the secrecy capacity of communications system significantly. The multiple hops in the relaying system is an important technique to improve this diversity gain. The development of an analytical mathematical model of ensuring security in multicasting through fading channels incorporating this benefit of multi-hop relaying is still an open problem. Motivated by this issue, this paper considers a secure wireless multicasting scenario employing multi-hop relaying technique over frequency selective Nakagami-m fading channel and develops an analytical mathematical model to ensure the security against multiple eavesdroppers. This mathematical model has been developed based on the closed-form analytical expressions of the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multicasting (SOPM) to ensure the security in the presence of multiple eavesdroppers. Moreover, the effects of the fading parameter of multicast channel, the number of hops and eavesdropper are investigated. The results show that the security in multicasting through Nakagami-m fading channel with multi-hop relaying system is more sensitive to the number of hops and eavesdroppers. The fading of multicast channel helps to improve the secrecy multicast capacity and is not the enemy of security in multicasting.

A Novel Beamforming Emulating Photonic Nanojets for Wireless Relay Networks

In this article,a low-cost electromagnetic structure emulating photonic nanojets is utilized to improve the efficiency of wireless relay networks.The spectral element method,due to its high accuracy,is used to verify the efficiency of the proposed structure by solving the associate field distribution.The application of optimal single-relay selection method shows that full diversity gain with low complexity can be achieved.In this paper,the proposed technique using smart relays combines the aforementioned two methods to attain the benefits of both methods by achieving the highest coding and diversity gain and enhances the overall network performance in terms of bit error rate(BER).Moreover,we analytically prove the advantage of using the proposed technique.In our simulations,it can be shown that the proposed technique outperforms the best known state-of-the-art single relay selection technique.Furthermore,the BER expressions obtained from the theoretical analysis are perfectly matched to those obtained from the conducted simulations.

Energy Efficient Constrained Shortest Path First-Based Joint Resource Allocation and Route Selection for Multi-Hop CRNs

Cognitive radio networks(CRNs) are expected to improve spectrum utilization efficiently by allowing secondary users(SUs) to opportunistically access the licensed spectrum of primary users(PUs).In CRNs,source and destination SUs may achieve information interaction in an ad hoc manner.In the case that no direct transmission link between the SU transmission pairs is available,multi-hop relay SUs can be applied to forward information for the source and destination SUs,resulting in multi-hop CRNs.In this paper,we consider a multi-hop CRN consisting of multiple PUs,SU transmission pairs and relay SUs.Stressing the importance of transmission hops and the tradeoff between data rate and power consumption,we propose an energy efficient constrained shortest path first(CSPF)-based joint resource allocation and route selection algorithm,which consists of two sub-algorithms,i.e.,CSPF-based route selection sub-algorithm and energy efficient resource allocation sub-algorithm.More specifically,we first apply CSPF-based route selection sub-algorithm to obtain the shortest candidate routes(SCRs) between the SU pair under the transmission constraints.Then,an energy efficient resource allocation problem of the SCRs is formulated and solved by applying iterative algorithm and Lagrange dual method.Simu-lation results demonstrate the effectiveness of the proposed algorithm.

Energy Efficiency in ARQ-Based Multi-Hop Systems and the Tradeoff with Throughput

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 constraints.Two ARQ protocols including type-I(ARQ-I)and repetition redundancy(ARQ-RR)are considered and expressions for the optimal power allocation(PA)are obtained.Using 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 obtained.It is shown that how different throughput requirements,especially the high levels,affect the EE performance.Additionally,asymptotic analysis is made in the feasible high throughput values and lower and upper EETT bounds are derived for ARQ-I protocol.To 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.

Two-Phase Bidirectional Dual-Relay Selection Strategy for Wireless Relay Networks

In this article,we introduce a new bi-directional dual-relay selection strategy with its bit error rate(BER)performance analysis.During the first step of the proposed strategy,two relays out of a set of N relay-nodes are selected in a way to optimize the system performance in terms of BER,based on the suggested algorithm which checks if the selected relays using the maxmin criterion are the best ones.In the second step,the chosen relay-nodes perform an orthogonal space-time coding scheme using the two-phase relaying protocol to establish a bi-directional communication between the communicating terminals,leading to a significant improvement in the achievable coding and diversity gain.To further improve the overall system performance,the selected relay-nodes apply also a digital network coding scheme.Furthermore,this paper discusses the analytical approximation of the BER performance of the proposed strategy,where we prove that the analytical results match almost perfectly the simulated ones.Finally,our simulation results show that the proposed strategy outperforms the current state-of-the-art ones.

Solar Energy Harvesting Using a Timer-Based Relay Selection

In this paper,the throughput and delay of cooperative communications are derived when solar energy is used and relay node is selected using a timer.The source and relays harvest energy from sun using a photo voltaic system.The harvested power is used by the source to transmit data to the relays.Then,a selected relay amplifies the signal to the destination.Opportunistic,partial and reactive relay selection are used.The relay transmits when its timer elapses.The timer is set to a value proportional to the inverse of its Signal to Noise Ratio(SNR).Therefore,the relay with largest SNR will transmit first and its signal will be detected by the other relays that will remain idle to avoid collisions.Harvesting duration is optimized to maximize the throughput.Packet’s waiting time and total delay are also computed.We also derive the statistics of SNR when solar energy is used.The harvested power from sun is proportional to the sum of a deterministic radiation intensity and a random attenuation due to weather effects and clouds occlusion.The fixed radiation intensity depends on season,month and time t in hour.The throughput of cooperative communications with energy harvesting from sun was not yet studied.

Design of multi-antenna relaying for OFDM in impulsive noise environment

A low-complexity multi-antenna relaying scheme is proposed for Orthogonal Frequency Division Multiplexing (OFDM) in the presence of Class-A Impulsive Noise (IN). One way and two way relaying are considered. The signal is transmitted and received by two terminal nodes, each with a single antenna in two time phases. In the proposed design, the processing at the relay consists of Maximal-Ratio Combining (MRC) or Power-based Selection Combining (PSC) for receive combining, Amplify and Forward (AF) for power scaling, and Space Time Block Coding (STBC) for transmit diversity. Channel State Information (CSI), Discrete Fourier Transform (DFT), and Inverse Discrete Fourier Transform (IDFT) are not needed. The Selective Mapping (SLM) technique is used at the transmitter to reduce the Peak-to-Average Power Ratio (PAPR) of the OFDM signal. Then, at the receiver, the clipping technique is used to reduce the impulses that result from the impulsive noise. The proposed system reduces the complexity of the conventional system, which uses multi-relay with a single antenna. Simulation results show that the Bit Error Rate (BER) of the proposed scheme outperforms that of the conventional scheme due to the diversity inherent in the proposed scheme.

Optimal coordination of directional over current relays using evolutionary programming

Co-ordination of directional over current relays(DOCR) requires the selection and setting of relays so as to sequentially isolate only that portion of the power system where an abnormality has occurred.The problem of coordinating protective relays in electrical power systems consists of selecting suitable settings such that their fundamental protective function is met,given operational requirements of sensitivity,selectivity,reliability and speed.Directional over current relays are best suited for protection of an interconnected sub-station transmission system.One of the major problems associated with this type of protection is the difficulty in coordinating relays.To insure proper coordination,all the main/back up relay pairs must be determined.This paper presents an effective algorithm to determine the minimum number of break points and main/back up relay pairs using relative sequence matrix(RSM).A novel optimization technique based on evolutionary programming was developed using these main/back up relay pairs for directional over current relay coordination in multi-loop networks.Since the problem has multi-optimum points,conventional mathematics based optimization techniques may sometimes fail.Hence evolutionary programming(EP) was used,as it is a stochastic multi-point search optimization algorithm capable of escaping from the local optimum problem,giving a better chance of reaching a global optimum.The method developed was tested on an existing 6 bus,7 line system and better results were obtained than with conventional methods.

球囊接力技术在急性颈内动脉串联闭塞治疗中的临床应用

目的探讨球囊接力技术在急性颈内动脉串联闭塞血管内治疗中的有效性和安全性。方法回顾性分析金华市中心医院2019年1月至2022年6月急性颈内动脉串联闭塞患者39例,根据手术方式分为球囊接力组(29例)和PEARS组(10例)。收集两组近端通路建立时间、血管再通时间、手术时间、取栓次数、血管再通程度、术中血栓逃逸、围手术期脑出血、术后大面积脑梗死、术后48 h美国国立卫生研究院卒中量表(NIHSS)评分、术后90 d改良Rankin量表(mRS)评分等临床指标,进行统计分析。结果球囊接力组近端通路建立时间、血管再通时间、手术时间、取栓次数、血管有效再通率、术中血栓逃逸率、术后NIHSS评分改善、大面积脑梗死、症状性颅内出血和术后mRS评分等方面均优于PEARS组,但两组间差异无统计学意义(均P>0.05)。结论在急性颈内动脉串联闭塞血管内治疗应用中,球囊接力技术具有安全性与有效性,在近端通路建立时间、血管再通时间、手术时间上可能有一定优势,在术中血栓逃逸、术后并发症以及术后神经功能恢复上可能存在潜在的优势,还需大样本研究进行验证。

第19届亚运会女子4×200米自由泳接力决赛成绩与技战术分析

本文运用文献资料法和视频解析法对第19届亚运会女子4×200米自由泳接力决赛成绩、跳发技术和战术安排进行分析,总结该项目前三名队伍的技战术规律,旨在为后续我国保持该项目的世界纪录提供参考。研究结论:中国队在女子4x200米项目上有很大的实力和优势;跳发技术属于影响最终成绩的因素,而队员的个人实力属于影响最终成绩的决定性因素。建议:注重后备人才的培养,勇于上新人,敢于用新手;运动员应当合理地分配前程、后程和冲刺阶段的体力;教练员应当针对运动员的不足,制定合理的训练计划。

金婺大桥桥塔竖向转体施工关键技术

金婺大桥主桥为(85+143+37)m独塔斜拉桥,采用塔墩梁固结体系,桥面以上塔柱高82.404 m,包括钢塔段(T1~T11)和3 m长钢-混结合段(T0)。钢塔采用整体竖向转体方式施工,总转体重量为2530 t,转动角度90°。由于钢塔较高、重量较大,钢塔在桥面上拼装后采用二次接力牵引竖转的方案施工,设置大、小压杆,首先由小压杆牵拉大压杆到一定角度,再由大压杆起扳钢塔。大、小压杆均采用门式空间桁架结构;钢塔转铰由上、下铰座和销轴组成,设置在T0与T1节段分节处。施工时,在桥面上分别以0°、13°、30°的倾角卧拼钢塔、大压杆、小压杆;通过小压杆和压杆牵引索牵拉大压杆到60°的倾斜位置,拆除小压杆进行体系转换;通过大压杆和钢塔牵引索牵拉钢塔从水平位置竖向转动到竖直位置,顺利完成钢塔竖向转体施工。

杭州亚运会男子4×100米自由泳接力决赛成绩与技战术分析

本文运用文献资料、数理统计、录像观察等方法对杭州亚运会男子4×100米自由泳接力决赛成绩、跳发技术和战术安排进行分析,旨在为我国实现该项目的突破提供参考。结果表明:①我国男子4×100米自由泳接力项目上有很强大的实力;②在该项目上,前三名的队伍除了首发选手采用的蹲踞式入水,其他选手都采用的新型跨步式入水;③前三名队伍都采用了争权夺标战术,中国队采用了先发制人战术,韩国队和日本队采用的后发制人战术。建议:我国要加强游泳项目的后备人才培养;运动员应当加强出发反应的练习,并且合理地分配比赛时的体力;教练员和运动员应当反复观看比赛视频,制定有针对性的训练计划;教练员在增加运动员训练量的同时,还应该做好后勤工作,及时进行营养补充,保证运动员的身体健康。

多哈世界游泳锦标赛男子4×100 m自由泳接力项目决赛成绩与技战术分析

目的:为中国队备战巴黎奥运会提供参考。方法:运用文献资料法、录像观察法、数理统计法等研究方法,对多哈世界游泳锦标赛男子4×100 m自由泳接力项目前3名的决赛成绩和技战术进行总结和分析。结论:(1)潘展乐开棒打破100 m自由泳世界纪录;(2)在跳发技术上,除了开棒运动员采用的蹲踞式入水外,其他运动员都采用的是新型跨步式入水;(3)中国队和意大利队采用了“先发制人”战术,美国队采用了“后发制人”战术,3支队伍都采用了“争权夺标”战术。建议:(1)中国队要重视游泳人才的选拔、训练和培养;(2)中国队运动员要重视交接棒的练习;(3)中国队运动员在赛前要保持好的心态;(4)中国队教练员要做好运动员的保障工作。

杭州亚运会男子4×100米混合泳接力决赛成绩与技战术分析

在分析杭州亚运会男子4×100米混合泳接力决赛中前三名队伍运动员决赛成绩、跳发技术、战术特征的基础上,运用文献资料、数理统计等研究方法,总结归纳前三名队伍的技战术特点,旨在为我国突破该项目提供参考。研究结论:①我国男子混合泳接力运动员的个人实力较其他两队运动员更强;②中国队交接棒时间没有其他队伍快;③决赛前三名队伍都采用了“争权夺标”战术。建议:提高训练量的同时要保障运动员的身体健康;运动员在训练中要加强交接棒的训练;教练员和运动员在赛后要对比赛进行多次回放分析;重视我国游泳项目后备人才的培养。

高脚竞速接力比赛中接力技术的研究——以第11届全国少数民族传统体育运动会为例

该文以2019年全国第11届少数民族传统体育运动会高脚竞速4×100m接力比赛决赛的8支队伍为调查对象,通过视频分析、对比分析法、数理统计法等研究方法,对高脚竞速接力比赛中接力环节进行研究。研究表明:(1)决赛中8支队伍呈现出了行进间交接方式和静止式交接方式两种不同的交接技术;(2)决赛成绩由高到低排名为湖北队、贵州队、广东队、广西队、陕西队、四川队、湖南队、江西队;(3)行进间交接方式交接用时少,容易造成失误,而静止式交接稳定性高,但交接耗时相对较长。基于此,提出以下建议:(1)选择适用接力技术并合理训练;(2)加强特定环境训练,增强技术稳定性;(3)注重专项体能训练,奠定竞赛基础;(4)推进科技助力,科学化训练体系。