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Epidemic threshold influenced by non-pharmaceutical interventions in residential university environments

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Chinese Physics B 2024年第2期33卷 551-556页

作者：卢泽超赵生妹束华中巩龙延 institute of signal processing and transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China College of Science Nanjing University of Posts and TelecommunicationsNanjing 210003China

The control of highly contagious disease spreading in campuses is a critical challenge.In residential universities,students attend classes according to a curriculum schedule,and mainly pack into classrooms,dining halls and dorms.They move from one place to another.To simulate such environments,we propose an agent-based susceptible–infected–recovered model with time-varying heterogeneous contact networks.In close environments,maintaining physical distancing is the most widely recommended and encouraged non-pharmaceutical intervention.It can be easily realized by using larger classrooms,adopting staggered dining hours,decreasing the number of students per dorm and so on.Their real-world influence remains uncertain.With numerical simulations,we obtain epidemic thresholds.The effect of such countermeasures on reducing the number of disease cases is also quantitatively evaluated.

关键词： epidemic threshold susceptible-infected-recovered model non-pharmaceutical interventions time-varying heterogeneous contact networks

Performance evaluation of half-duplex relay-based opportunistic cooperation diversity

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Science China(Information Sciences) 2010年第2期53卷 325-334页

作者： ZOU YuLong , ZHENG BaoYu & ZHU Jia institute of signal processing and transmission, Nanjing University of Posts and Telecommunications, Nanjing 210003, China institute of signal processing and transmission Nanjing University of Posts and Telecommunications Nanjing China

Cooperative diversity is proposed as a means to improve the wireless transmission performance, which can effectively combat the wireless fading through sharing the antennas between source and relay nodes. In this paper, considering the practicability, we investigate the use of half-duplex relay, rather than full-duplex relay, for the opportunistic cooperation diversity. Two combining methods, namely selection diversity combining (SDC) and maximum ratio combining (MRC), are utilized for the implementation of the half-duplex relay-based opportunistic cooperation. Closed-form expressions of outage probability are derived for the proposed oppor- tunistic cooperation as well as the known deterministic cooperation over Rayleigh fading channels. Numerical results show that the opportunistic cooperation is superior to the traditional deterministic cooperation in terms of outage probability and, moreover, the MRC-based case outperforms the SDC-based case no matter which duplex mode relay (i.e., half-duplex and full-duplex) is used for the opportunistic cooperation.

关键词： half-duplex relay cooperative diversity SDC MRC outage probability

Gray code based gradient-free optimization algorithm for parameterized quantum circuit

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Chinese Physics B 2024年第2期33卷 189-194页

作者：张安琪武春辉赵生妹 institute of signal processing and transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology(Ministry of Education) Nanjing University of Posts and TelecommunicationsNanjing 210003China

A Gray code based gradient-free optimization(GCO)algorithm is proposed to update the parameters of parameterized quantum circuits(PQCs)in this work.Each parameter of PQCs is encoded as a binary string,named as a gene,and a genetic-based method is adopted to select the offsprings.The individuals in the offspring are decoded in Gray code way to keep Hamming distance,and then are evaluated to obtain the best one with the lowest cost value in each iteration.The algorithm is performed iteratively for all parameters one by one until the cost value satisfies the stop condition or the number of iterations is reached.The GCO algorithm is demonstrated for classification tasks in Iris and MNIST datasets,and their performance are compared by those with the Bayesian optimization algorithm and binary code based optimization algorithm.The simulation results show that the GCO algorithm can reach high accuracies steadily for quantum classification tasks.Importantly,the GCO algorithm has a robust performance in the noise environment.

关键词： gradient-free optimization Gray code genetic-based method

Cyclostationary Property Based Spectrum Sensing Algorithms for Primary Detection in Cognitive Radio Systems

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Journal of Shanghai Jiaotong university(Science) 2009年第6期14卷 676-680页

作者：岳文静郑宝玉孟庆民 Department of Electronic Engineering Shanghai Jiaotong University institute of signal processing and transmission Nanjing University of Posts and Telecommunications

To implement the primary signal without interference in cognitive radio systems,cognitive radios can detect the presence of the primary user in low SNR.Currently,energy detector is the most common way of spectrum sensing because of its low computational complexity.However,performance of the method will be possibly degraded due to the uncertainty noise.This paper illustrates the benefits of one-order and two-order cyclostationary properties of primary user's signals in time domain.These feature detection techniques in time domain possess the advantages of simple structure and low computational complexity comparing with spectral feature detection methods.Furthermore,performance of the one-order and two-order feature detection is studied and the analytical results are given.Our analysis and numerical results show that the sensing performance of the one-order feature detection is improved significantly comparing with conventional energy detector since it is robust to noise.Meanwhile,numerical results show that the two-order feature detection technique is better than the one-order feature detection.However,this benefit comes at the cost of hardware burdens and power consumption due to the additional multiplying algorithm.

关键词：循环平稳特性无线电频谱检测系统算法遥感财产光谱特征干扰信号

Robust cooperative spectrum sensing schemes for fading channels in cognitive radio networks

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Science China(Information Sciences) 2011年第2期54卷 348-359页

作者： YUE WenJing1,2, ZHENG BaoYu1,2, MENG QingMin1, CUI JingWu1 & XIE PeiZhong1 1institute of signal processing and transmission, Nanjing University of Posts and Telecommunications, Nanjing 210003, China 2Department of Electronic Engineering, Shanghai Jiaotong University, Shanghai 200240, China institute of signal processing and transmission Nanjing University of Posts and Telecommunications Nanjing China Department of Electronic Engineering Shanghai Jiaotong University Shanghai China

In cognitive radio systems, cooperative spectrum sensing can detect the presence of the primary user accurately. In practice, however, since the sensing observations are forwarded to a data collector through fading channels, the sensing performance is severely degraded. To deal with this problem, in this paper, we first propose a secondary user selection based cooperative spectrum sensing method to improve sensing performance by decreasing the reporting errors introduced by the fading channels. More specifically, only the secondary users with better signal-to-noise ratio (SNR) for reporting channels are allowed to send their local binary decisions (0 or 1) to the data collector while the others will send nothing. Additionally, we further propose a diversity based cooperative spectrum sensing method which applies existing space-time coding. By exploiting space diversity in CR network, the reporting errors introduced by the fading channel can be decreased and then the sensing performance is improved significantly. For either proposed cooperative spectrum sensing method, the sensing performance is derived and the analytical performance results are given. Our analysis and numerical results verify that proposed methods outperform the conventional cooperative spectrum sensing with OR-rule by taking into account the error effect on the reporting channels.

关键词： cognitive radio (CR) spectrum sensing energy detection diversity technique space-time coding

BLIND CHANNEL AND SYMBOL JOINT ESTIMATION IN COOPERATIVE MIMO FOR WIRELESS SENSOR NETWORK

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Journal of Electronics(China) 2008年第4期25卷 439-444页

作者： Yan Zhenya Zheng Baoyu institute of signal processing ＆ transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China

In this paper,application of Sequential Quasi Monte Carlo(SQMC)to blind channel andsymbol joint estimation in cooperative Multiple-Input Multiple-Output(MIMO)system is proposed,which does not need to transmit training symbol and can save the power and channel bandwidth.Additionally,an improved version of SQMC algorithm by taking advantage of current received signal isdiscussed.Simulation results show that the SQMC method outperforms the Sequential Monte Carlo(SMC)methods,and the incorporation of current received signal improves the performance of theSQMC obviously.

关键词：多输入多输出系统通信系统传感器网络连续拟蒙特卡洛法盲信道

Diffraction deep neural network-based classification for vector vortex beams

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Chinese Physics B 2024年第3期33卷 387-392页

作者：彭怡翔陈兵王乐赵生妹 institute of signal processing and transmission Nanjing University of Posts and Telecommunications (NJUPT)Nanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing 210003China National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China

The vector vortex beam(VVB)has attracted significant attention due to its intrinsic diversity of information and has found great applications in both classical and quantum communications.However,a VVB is unavoidably affected by atmospheric turbulence(AT)when it propagates through the free-space optical communication environment,which results in detection errors at the receiver.In this paper,we propose a VVB classification scheme to detect VVBs with continuously changing polarization states under AT,where a diffractive deep neural network(DDNN)is designed and trained to classify the intensity distribution of the input distorted VVBs,and the horizontal direction of polarization of the input distorted beam is adopted as the feature for the classification through the DDNN.The numerical simulations and experimental results demonstrate that the proposed scheme has high accuracy in classification tasks.The energy distribution percentage remains above 95%from weak to medium AT,and the classification accuracy can remain above 95%for various strengths of turbulence.It has a faster convergence and better accuracy than that based on a convolutional neural network.

关键词： vector vortex beam diffractive deep neural network classification atmospheric turbulence

A novel multi-relay cross-layer cooperative communication strategy based on Jackson queuing model

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Science China(Information Sciences) 2010年第4期53卷 842-853页

作者： XU XiaoRong1,2* & ZHENG BaoYu1 1institute of signal processing and transmission, Nanjing University of Posts and Telecommunications, Nanjing 210003, China 2College of Telecommunication Engineering, Hangzhou Dianzi University, Hangzhou 310018, China institute of signal processing and transmission Nanjing University of Posts and Telecommunications Nanjing China College of Telecommunication Engineering Hangzhou Dianzi University Hangzhou China

A novel multi-relay cooperative communication strategy based on Jackson queuing model is pro-posed, which is implemented via a cross-layer design between the physical (PHY) layer and the medium access control (MAC) layer. In the PHY layer, we focus mainly on system outage performance by analyzing in detail the relationship between the SNR threshold and the outage probabilities. While in the MAC layer, system model is treated as a Jackson queuing network, and the queue discipline for each node is assumed to be GI/M/1 model. System throughput and delay performance for the proposed strategy are also illustrated. Simulation results of the proposed cross-layer scheme are presented to validate our theoretical derivations. It is revealed that, the number of cooperative nodes influences system outage performance at high spectral efficiency regimes in the PHY layer while the proposed strategy provides a better throughput and delay performance than conventional schemes in the MAC layer.

关键词： multi-relay cooperative communication cross-layer design Jackson queuing model outage prob- abilities GI/M/1 model system throughput delay performance

Achievable bit rates of cognitive user with Vandermonde precoder in cognitive radio network

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Science China(Information Sciences) 2011年第7期54卷 1471-1480页

作者： XU XiaoRong 1,ZHANG JianWu 1 & ZHENG BaoYu 2 1 College of Telecommunication Engineering,Hangzhou Dianzi University,Hangzhou 310018,China 2 institute of signal processing and transmission,Nanjing University of Posts and Telecommunications,Nanjing 210003,China College of Telecommunication Engineering Hangzhou Dianzi University Hangzhou China institute of signal processing and transmission Nanjing University of Posts and Telecommunications Nanjing China

In cognitive radio network (CRN) where primary user (PU) and secondary user (SU) wish to communicate with their corresponding receivers simultaneously over frequency selective fading channels,the interference between PU and SU should be eliminated in order to realize spectrum sharing.Precoder division multiple access (PDMA) that implements Vandermonde precoder in cognitive orthogonal frequency division multiplexing (OFDM) is proposed,which benefits from the frequency selectivity of the cognitive channel to form a frequency beam-former.Vandermonde precoder enables SUs to achieve higher bit rate with optimal power allocation strategy under the condition of PU interference constraint.Numerical and simulation results are presented to prove theoretical derivations.It is shown that,achievable bit rates (ABR) of SU could be achieved with optimal power allocation scheme in CRN.Meanwhile,it is also verified that,with Vandermonde precoder to form PDMA,SU’s signal-to-noise ratio (SNR) and the target rate of PU could impact the ABR of SU significantly in CRN.

关键词： achievable bit rates (ABR) Vandermonde precoder precoder division multiple access (PDMA) optimal power allocation cognitive radio network (CRN)