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Quasi-concave optimization of secrecy redundancy rate in HARQ-CC system

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Science China(Information Sciences) 2020年第2期63卷 160-173页

作者： Yue WU Shishu YIN Jian ZHOU Pei yang Hongwen Yang School of Management Science and Engineering Anhui University of Finance and Economics School of Information and Communication Engineering Beijing University of Posts and Telecommunications

In a hybrid automatic repeat request with chase combining(HARQ-CC) system, we analyze physical layer secure performance and determine the secrecy redundancy rate by proposed quasi-concave optimization methods with effective secrecy throughput(EST) criteria. First, key performance metrics,including connection outage probability(COP), secrecy outage probability(SOP), EST, and delay, are discussed. Then, under the constraint of COP, we optimize the secrecy redundancy rate to maximize the EST,which is a quasi-concave function, by both the bisection and fixed-point methods. Furthermore, under the simultaneous constraints of COP and SOP, the bisection and Lagrangian multiplier methods are applied to optimize the secrecy redundancy rate. From the comparison of the numerical and simulated results, it is concluded that EST demonstrates practical secure performance of HARQ-CC, and the proposed optimization methods adjust the secrecy redundancy rate for improved security.

关键词： physical layer security(PLS) hybrid automatic repeat request(HARQ) chase combining(CC) effective secrecy throughput(EST) quasi-concave optimization

Concurrent channel and spatial attention in Fully Convolutional Network for individual pig image segmentation

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International Journal of Agricultural and Biological Engineering 2023年第1期16卷 232-242页

作者： Zhiwei Hu Hua yang Tiantian Lou hongwen Yan College of Information Science and Engineer Shanxi Agricultural UniversityTaigu 030801ShanxiChina School of Computer and Information Technology(School of Big Data) Shanxi UniversityTaiyuan 03006China College of Agricultural Economics&Management Shanxi Agricultural UniversityTaigu 030801ShanxiChina

The separation of individual pigs from the pigpen scenes is crucial for precision farming,and the technology based on convolutional neural networks can provide a low-cost,non-contact,non-invasive method of pig image segmentation.However,two factors limit the development of this field.On the one hand,the individual pigs are easy to stick together,and the occlusion of debris such as pigpens can easily make the model misjudgment.On the other hand,manual labeling of group-raised pig data is time-consuming and labor-intensive and is prone to labeling errors.Therefore,it is urgent for an individual pig image segmentation model that can perform well in individual scenarios and can be easily migrated to a group-raised environment.In order to solve the above problems,taking individual pigs as research objects,an individual pig image segmentation dataset containing 2066 images was constructed,and a series of algorithms based on fully convolutional networks were proposed to solve the pig image segmentation problem.In order to capture the long-range dependencies and weaken the background information such as pigpens while enhancing the information of individual parts of pigs,the channel and spatial attention blocks were introduced into the best-performing decoders UNet and LinkNet.Experiments show that using ResNext50 as the encoder and Unet as the decoder as the basic model,adding two attention blocks at the same time achieves 98.30%and 96.71%on the F1 and IOU metrics,respectively.Compared with the model adding channel attention block alone,the two metrics are improved by 0.13%and 0.22%,respectively.The experiment of introducing channel and spatial attention alone shows that spatial attention is more effective than channel attention.Taking VGG16-LinkNet as an example,compared with channel attention,spatial attention improves the F1 and IOU metrics by 0.16%and 0.30%,respectively.Furthermore,the heatmap of the feature of different layers of the decoder after adding different attention information proves that with the increase

关键词： pig image segmentation Fully Convolutional Network(FCN) attention mechanism channel and spatial attention

The Analysis of Secure HARQ with Chase Combining over Block Fading Channel

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中国通信：英文版 2016年第5期13卷 82-88页

作者： Yue Wu Lukman A Olawoyin Nana Zhang Hongwen Yang Wireless Communication Center School of Information and Communication EngineeringBeijing University of Posts and Telecommunications

In this letter, the physical layer security of hybrid automatic repeat request with chase combining(HARQ-CC) scheme is investigated from the viewpoint of information theory. Different from the literature which used Wyner code, our analysis focuses on the general scenario without specific code. We firstly obtain the outage probability of both main channel and wiretap channel. Since retransmissions are completely determined by main channel, we then prove that its achievable diversity order equals to maximum transmission number() while this order of wiretap channel is only one. Furthermore, we evaluate the metric of secure gap which demonstrates the difference between main channel and wiretap channel with reliable and secure constraints. As increases, the secure gap decreases monotonously. When is large enough, the security can be guaranteed even if wiretap channel is better than main channel.

关键词：衰落信道安全分析 HARQ 混合自动重复请求物理层安全中断概率安全约束单调下降

Energy efficient HARQ scheme for wireless communication over block fading channel

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The Journal of China Universities of Posts and Telecommunications 2015年第3期22卷 35-40页

作者： Wu Yue yang hongwen Wireless Communication Center Beijing University of Posts and Telecommunications

Energy efficiency （EE） can be enhanced by retransmissions and combining in hybrid automatic repeat request （HARQ） system. However, it is difficult to optimize the transmit power of each retransmission when the accurate retransmission number and future channel state information （CSI） cannot be obtained. This paper proposes a simple energy efficient HARQ scheme for point-to-point wireless communication. In the proposed scheme, the conditional word error rate （WER） of each retransmission is fixed and the transmit power is adapted correspondingly. Three performance metrics are analyzed including average transmission number, throughput and EE. Compared with the conventional equal power HARQ scheme, the proposed scheme can significantly improve the EE and other two metrics under the same constraint of average transmit power or average energy consumption. Furthermore, it is found that, selecting a conditional WER which is slightly smaller than the optimal one is sufficient for practical implementation.

关键词： Energy efficiency hybrid automatic repeat request （HARQ） conditional word error rate

Numerical simulations of failure behavior around a circular opening in a non-persistently jointed rock mass under biaxial compression

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International Journal of Mining Science and Technology 2016年第4期26卷 729-738页

作者： yang Xuxu Jing hongwen Chen Kunfu Rock Mass Modeling and Computational Rock Mechanics Laboratories University of Arizona State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology

Pre-existing discontinuities change the mechanical properties of rock masses,and further influence failure behavior around an underground opening.In present study,the failure behavior in both Inner and Outer zones around a circular opening in a non-persistently jointed rock mass under biaxial compression was investigated through numerical simulations.First,the micro parameters of the PFC^(3D) model were carefully calibrated using the macro mechanical properties determined in physical experiments implemented on jointed rock models.Then,a parametrical study was undertaken of the effect of stress condition,joint dip angle and joint persistency.Under low initial stress,the confining stress improves the mechanical behavior of the surrounding rock masses;while under high initial stress,the surrounding rock mass failed immediately following excavation.At small dip angles the cracks around the circular opening developed generally outwards in a step-path failure pattern;whereas,at high dip angles the surrounding rock mass failed in an instantaneous intact rock failure pattern.Moreover,the stability of the rock mass around the circular opening deteriorated significantly with increasing joint persistency.

关键词：节理岩体破坏行为数值模拟双轴压缩圆形洞室围岩宏观力学性能岩体稳定性

Design and experiment of pneumatic seed clearing mechanism for pin-hole tube wheat plot precision sowing device

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International Journal of Agricultural and Biological Engineering 2023年第4期16卷 85-95页

作者： Xirui Zhang Youming yang Qingjie Wang hongwen Li Zhifu Zhang Junxiao Liu School of Mechanical and Electrical Engineering Hainan UniversityHaikou 570228China College of Engineering China Agricultural UniversityBeijing 100083China Sanya Nanfan Research Institute of Hainan University Sanya 572025HainanChina

For the problem that when wheat is sucked up by the air suction method,the seeds are aligned in a small area,making it difficult for the contact seed cleaning mechanism to clean the seeds.The mechanism of seed cleaning airflow on wheat seed was studied,the flow velocity distribution relationship of the jet section was defined,the mathematical model of the jet velocity of circular and plane sections was established,and the key factors that could have a significant influence on seed cleaning effect were explored.A non-contact positive pressure air flow seed cleaning method was proposed.After theoretical calculations,it is concluded that the core section lengths of the circular section jet and the inline jet are 24.8 mm and 28.8 mm,respectively.The clearing distance is set to 20 mm.Through the single-factor test,the best air tube nozzle shape was clarified as a vertical inline nozzle.The angle of seed cleaning,the air velocity of seed cleaning,and the negative supply pressure were selected as influencing factors,and the seed leakage index,seed reabsorption index,and seed qualification index as the evaluation indicators to conduct a 3-factor 5-horizontal rotation test.A mathematical regression model of influencing factors and evaluation indexes was established to analyze the influence of these factors and indexes.The optimal operation parameters were obtained as the seed cleaning Angle of 19°,the seed cleaning air velocity of 58 m/s,and the negative pressure of 8.5 kPa.Under the optimal parameters,the seed leakage suction index is 8.23%,the seed reabsorption index is 0.33%,and the seed qualification index is 91.44%,which meets the design requirements.

关键词： wheat precision seed-metering device clearing seed positive pressure airflow jet flow field

BER Modified Decode-and-Forward Protocol for OFDM-Based Linear Multihop Networks

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China Communications 2014年第11期11卷 34-43页

作者： MIAO Tingting WANG Ning yang Hongwen Yang Dachcng Beijing University of Posts and TeLecommunications Beijing 100876 China

In orthogonal frequency division multiplexing(OFDM) based muitihop communications,the conventional decodeand-forward(DF) relay scheme severely suffers from the error propagation problem.This drawback is serious in muitihop networks as errors made by any relay node may fail the decoder at the destination in great chance.In this paper,we propose a bit error rate(BER)modified DF protocol(BMDF) which can be applied to systems where error correction channel coding and M-ary modulation are used.By modeling all links except the last one as a binary symmetric channel(BSC),we derive a log likelihood ratio(LLR)modification function relying only on the accumulated BER of all previous links to be applied to the output of the soft demapper.Furthermore,to reduce the computational complexity and signaling overhead,the modification function is simplified from its original exponential expression and less BERs are delivered between nodes by making successive subcarriers share the same BER.In addition,for situations where the channel state information(CSI) of forward link is available,the proposed BMDF can be further enhanced by combining with subcarrier pairing(SP) and power allocation(PA),where a sorted-channel gain SP scheme and a greedy PA algorithm are proposed.The simulation results verify the significant performance improvement to the conventional DF.

关键词：多跳网络 OFDM 误码率解码器协议转发二进制对称信道线性

Early termination strategy of HEVC based on statistical models

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The Journal of China Universities of Posts and Telecommunications 2019年第5期26卷 72-81页

作者： Liu Yitong Tian Wang Li Yuchen yang hongwen School of Information and Communication Engineering Beijing University of Posts and Telecommunications

High efficiency video coding(HEVC)uses half of the bitrate compared to H.264/advanced video coding(AVC)for encoding the same sequence with similar quality.Because of the advanced hierarchical structures of coding units(CUs),predicting units(PUs),and transform units(TUs),HEVC can better adapt when encoding full high definition(HD)and ultra high definition(UHD)videos.At the expense of encoding efficiency,the complexity of HEVC sharply increases compared to H.264/AVC,mainly due to its quad-tree structure that splits pictures.In this study,the probability distribution,which is generated by a rate distortion optimizing(RDO)cost,is analyzed.Then,an early terminating method is proposed to decrease the complexity of the HEVC based on probability distributions.The experiment shows that the coding time is reduced by 44.9%for HEVC intra coding,at the cost of a 0.61%increase in the Bj?ntegaard delta rate(BD-rate),on average.

关键词： HEVC early termination statistical model fast algorithm

A random linear code based secure transmission scheme for wireless fading channels

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Science China(Information Sciences) 2017年第4期60卷 241-243页

作者： Lukman A.OLAWOYIN Nana ZHANG A.O.OLOYEDE Nasir FARUK Hongwen Yang Wireless Communication Center Beijing University of Posts and Telecommunications Department of Telecommunication Science University of Ilorin

Dear editor,Wireless transmissions are vulnerable to potential security threats such as eavesdropping and wiretapping since unauthorized reception is facilitated through wireless channels[1].Traditional system security is mainly implemented in the higher layers of the communication protocol stack,relying on authentication and cryptography[2].The recent researches explore security in the physical layer[3],which can help to protect the information

关键词： code length A random linear code based secure transmission scheme for wireless fading channels