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Acta Mechanica Solida Sinica 2023年第2期36卷 327-339页

作者： Mingzhi wang Guitao Zhang Tingguang Liu weidong wang School of Mechano-Electronic Engineering Xidian UniversityXi’an 710071China CityU-Xidian Joint Laboratory of Micro/Nano Manufacturing Shenzhen 518057China National Center for Materials Service Safety University of Science and Technology BeijingBeijing 100083China

The instrumented nanoindentation technique has been widely used to measure the tensile properties of various materials,for its simple specimen preparation and nearly nondestructive testing *** this paper,a novel inverse method is established for measuring the elastoplastic properties of Al 2024 *** grid indentation experiments are performed on Al 2024 *** obtained experimental load–displacement(P–h)data exhibit obvious scatter *** artificial neural network(ANN)model with tunable hyper-parameters is adopted to establish the forward relationship between elastoplastic parameters and indentation load–displacement *** objective function for quantifying the error norm between predicted and experimental P–h snapshots is *** parameter identification problem is solved using the“interior-point”constraint optimization algorithm..The identified material properties show good agreement with the tensile data,and the error values are−8.66%for elastic modulus,1.08%for yield stress,and 6.90%for hardening *** sensitivity of numerical results to experimental uncertainty is analyzed,and the error bound of experimental data is *** results of sensitivity analysis indicate that the proposed inverse method in the work is very effective and reliable.

关键词： Nanoindentation Material properties Al 2024 alloy Deep learning Parameter identification

Quantum entropy based tabu search algorithm for energy saving in SDWN

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Science China(Information Sciences) 2017年第4期60卷 85-100页

作者： Chaowei wang Wuyang MEI Xiangying QIN weidong wang School of Electronic Engineering Beijing University of Posts and Telecommunications

The energy consumption of the base station(BS) accounts for great proportion of the total wireless access network(WAN). Switching off the selected spare BSs with few network request would save a large amount of energy. It is difficult to deploy a BS energy saving strategy in existing network architecture due to the tightly coupled network devices. Therefore, we adopt the software defined wireless networks(SDWN) structure which is an sample of the wireless software defined networks(SDN). Then a novel quantum entropy based tabu search algorithm(QETS) is proposed to choose which BS to switch off, and it increases the search range and guarantee the convergence speed. The energy saving strategy can find the optimal solution with higher probabilities and can be deployed in centralized controller as a software. Theoretical analysis and simulation results show the QETS algorithm's gain over the greedy algorithm and quantum inspired tabu search algorithm(QTS) in terms of convergence.

关键词： energy saving SDN SDWN quantum entropy quantum inspired tabu search algorithm

A study of the perforation of stiffened plates by rigid projectiles

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Acta Mechanica Sinica 2005年第6期21卷 582-591页

作者： Jianguo Ning weidong Song Jing wang State Key Laboratory of Explosion Science and TechnologyBeijing Institute of Technology Beijing 100081 China

In the present paper, a four-stage perforation model that accurately predicts the residual velocity is developed by adopting an energy method. The four stages are plug formation, dishing formation, petal formation and projectile exit. In addition, some important experimental results are presented and analyzed to validate the present perforation model. In the experiments, high speed camera system is used to record the perforation process. Observations on target damage and measurements of initial velocities and residual velocities with the aid of the system are presented. Numerical simulations are carried out for projectiles against single and layered plates adopted in the experiments. The perforation process is studied and the deformation and failure modes are obtained. The predictions of numerical simulations and analytical model are found in reasonably good agreement with those of experiments, and can be used to predict the ballistic limit and residual velocity of stiffened plates perforated by rigid projectiles.

关键词： Perforation Penetration Impact Stiffened plate Numerical simulations Failure modes

Dynamic Uplink Transmission Scheduling for Satellite Internet of Things Applications

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China Communications 2020年第10期17卷 241-248页

作者： Li wang Shuaijun Liu weidong wang Zhiyan Fan Beijing University of Posts and Telecommunications Beijing 100876China China Academy of Information and Communications Technology Beijing 100191China Institute of Software Chinese Academy of Sciences Beijing 100190China

Satellite communication systems provide a cost-effective solution for global internet of things(IoT)applications due to its large coverage and easy *** paper mainly focuses on Satellite networks system,in which low earth orbit(LEO)satellites network collect sensing data from the user terminals(UTs)and then forward the data to ground station through geostationary earth orbit(GEO)satellites *** the limited uplink transmission resources,this paper optimizes the uplink transmission scheduling scheme over LEO satellites.A novel transmission scheduling algorithm,which combined Algorithms of Simulated Annealing and Monte Carlo(SA-MC),is proposed to achieve the dynamic optimal scheduling *** results show the effectiveness of the proposed SA-MC algorithm in terms of cost value reduction and fast convergence.

关键词： satellite IoT transmission scheduling resource allocation simulated annealing Monte Carlo

Trajectory Optimization and Power Allocation Scheme Based on DRL in Energy Efficient UAV-Aided Communication Networks

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Chinese Journal of Electronics 2022年第3期31卷 397-407页

作者： wang Chaowei CUI Yuling DENG Danhao wang weidong JIANG Fan School of Electronic Engineering Beijing University of Posts and Telecommunications Key Laboratory of Universal Wireless Communications Ministry of Education School of Telecommunications and Information Engineering Xi'an University of Posts and Telecommunications

With flexibility, convenience and mobility, unmanned aerial vehicles(UAVS) can provide wireless communication networks with lower costs, easier deployment, higher network scalability and larger *** paper proposes the deep deterministic policy gradient algorithm to jointly optimize the power allocation and flight trajectory of UAV with constrained effective energy to maximize the downlink throughput to ground users. To validate the proposed algorithm, we compare with the random algorithm, Q-learning algorithm and deep Q network algorithm. The simulation results show that the proposed algorithm can effectively improve the communication quality and significantly extend the service time of UAV. In addition, the downlink throughput increases with the number of ground users.

关键词： unmanned aerial vehicles remotely operated vehicles trajectory optimization Q-learning algorithm power allocation scheme flight trajectory communication quality optimisation mobile robots random algorithm deep Q network algorithm learning systems constrained effective energy ground users autonomous aerial vehicles network scalability resource allocation UAVS energy efficient UAV-aided communication networks gradient methods deep deterministic policy gradient algorithm trajectory control radio networks wireless communication networks

Anomalous Cell Detection with Kernel Density-Based Local Outlier Factor

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China Communications 2015年第9期12卷 64-75页

作者： Miao Dandan Qin Xiaowei wang weidong Key Laboratory of Wireless-Optical Communications Chinese Academy of Sciences School of Information Science and TechnologyUniversity of Science and Technology of China

Since data services are penetrating into our daily life rapidly, the mobile network becomes more complicated, and the amount of data transmission is more and more increasing. In this case, the traditional statistical methods for anomalous cell detection cannot adapt to the evolution of networks, and data mining becomes the mainstream. In this paper, we propose a novel kernel density-based local outlier factor(KLOF) to assign a degree of being an outlier to each object. Firstly, the notion of KLOF is introduced, which captures exactly the relative degree of isolation. Then, by analyzing its properties, including the tightness of upper and lower bounds, sensitivity of density perturbation, we find that KLOF is much greater than 1 for outliers. Lastly, KLOFis applied on a real-world dataset to detect anomalous cells with abnormal key performance indicators(KPIs) to verify its reliability. The experiment shows that KLOF can find outliers efficiently. It can be a guideline for the operators to perform faster and more efficient trouble shooting.

关键词： data mining key performance indicators kernel density-based local outlier factor density perturbation anomalous cell detection

Intelligent Spectrum Detection Model Based on Compressed Sensing in Cognitive Radio Network

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Computer Modeling in Engineering & Sciences 2020年第2期122卷 691-701页

作者： Yanli Ji weidong wang Yinghai Zhang School of Network Education Beijing University of Posts and TelecommunicationsBeijingChina. Information and Electronic Technology Lab Beijing University of Posts and TelecommunicationsBeijingChina.

In view of the uncertainty of the status of primary users in cognitive networks and the fact that the random detection strategy cannot guarantee cognitive users to accurately find available channels,this paper proposes a joint random detection strategy using the idle cognitive users in cognitive wireless *** adding idle cognitive users for detection,the compressed sensing model is employed to describe the number of available channels obtained by the cognitive base station to derive the detection performance of the cognitive network at this *** theoretical analysis and simulation results show that using idle cognitive users can reduce service delay and improve the throughput of cognitive *** considering the time occupied by cognitive users to report detection information,the optimal participation number of idle cognitive users in joint detection is obtained through the optimization algorithm.

关键词： Cognitive wireless network compressed sensing intelligent frequency spectrum detection random detection.

Frequency Offset Compensation for Satellite Communication System with CE-OFDM

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China Communications 2017年第8期14卷 93-104页

作者： Gaofeng Cui Cheng wang weidong wang Yinghai Zhang Key Laboratory of Universal Wireless Communications Ministry of Education Information&Electronics Technology Lab School of Electronic EngineeringBeijing University of Posts and Telecommunications

Constant envelope orthogonal frequency division multiplexing(CE-OFDM) is a waveform that can achieve 0d B peak-to-average power ratio and avoid the signal distortion caused by the nonlinear power amplifi er. However, the carrier frequency offset(CFO) in CE-OFDM systems can cause errors at phase unwrapper module. In this paper, a CFO estimation scheme is proposed for CEOFDM in satellite communication system. As the null subcarrier is inherent in the conjugate symmetric symbol structure at the transmitter, the proposed scheme uses the null subcarrier as prior information to estimate the CFO at the receiver. The ideal estimation range of normalized CFO is obtained by mathematical analysis. Simulation results show that the proposed scheme can estimate the CFO accurately under additive white Gaussian noise(AWGN) channel and multipath fading channel, especially for moderate and high signal-to-noise ratio(SNR).

关键词： CE-OFDM carrier frequency offset null subcarrier satellite communication

Infinite-dimensional 3-Lie algebras and their ：onnections to Harish-Chandra modules

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Frontiers of Mathematics in China 2017年第3期12卷 515-530页

作者： Ruipu BAI Zhenheng LI weidong wang College of Mathematics and Information Science Hebei University Baoding 071002 China Department of Mathematical Sciences University of South Carolina Aiken Aiken SC 29801 USA

We construct two kinds of infinite-dimensional 3-Lie algebras from a given commutative associative algebra, and show that they are all canonical Nambu 3-Lie algebras. We relate their inner derivation algebras to Witt algebras, and then study the regular representations of these 3-Lie algebras and the natural representations of the inner derivation algebras. In particular, for the second kind of 3-Lie algebras, we find that their regular representations are Harish-Chandra modules, and the inner derivation algebras give rise to intermediate series modules of the Witt algebras and contain the smallest full toroidal Lie algebras without center.

关键词： 3-Lie algebra Harish-Chandra module Witt algebra intermediate series module toroidal Lie algebra inner derivation algebra

Joint Estimation of Carrier Frequency and Phase Offset Based on Pilot Symbols in Quasi-Constant Envelope OFDM Satellite Systems

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China Communications 2017年第7期14卷 184-194页

作者： Cheng wang Gaofeng Cui weidong wang Yinghai Zhang Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications

Spectral efficiency and energy efficiency are two important performance indicators of satellite systems. The Quasi-Constant Envelope Orthogonal Frequency Division Multiplexing(QCE-OFDM) technique can achieve both high spectral efficiency and low peak-to-average power ratio(PAPR). Therefore, the QCE-OFDM technique is considered as a promising candidate multi-carrier technique for satellite systems. However, the Doppler effect will cause the carrier frequency offset(CFO), and the non-ideal oscillator will cause the carrier phase offset(CPO) in satellite systems. The CFO and CPO will further result in the bit-error-rate(BER) performance degradation. Hence, it is important to estimate and compensate the CFO and CPO. This paper analyzes the effects of both CFO and CPO in QCE-OFDM satellite systems. Furthermore, we propose a joint CFO and CPO estimation method based on the pilot symbols in the frequency domain. In addition, the optimal pilot symbol structure with different pilot overheads is designed according to the minimum Cramer-Rao bound(CRB) criterion. Simulation results show that the estimation accuracy of the proposed method is close to the CRB.

关键词： carrier frequency offset carrier phase offset pilot symbol structure quasi-constant envelope OFDM satellite systems.