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Bessel–Gaussian beam-based orbital angular momentum holography

Chinese Physics B 2024年第1期33卷 407-413页

作者：季佳滢郑志刚朱家龙王乐王新光赵生妹 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 EducationNanjing 210003China National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China

Orbital angular momentum(OAM), as a new degree of freedom, has recently been applied in holography *** to the infinite helical mode index of OAM mode, a large number of holographic images can be reconstructed from an OAM-multiplexing hologram. However, the traditional design of an OAM hologram is constrained by the helical mode index of the selected OAM mode, for a larger helical mode index OAM mode has a bigger sampling distance, and the crosstalk is produced for different sampling distances for different OAM modes. In this paper, we present the design of the OAM hologram based on a Bessel–Gaussian beam, which is non-diffractive and has a self-healing property during its propagation. The Fourier transform of the Bessel–Gaussian beam is the perfect vortex mode that has the fixed ring radius for different OAM modes. The results of simulation and experiment have demonstrated the feasibility of the generation of the OAM hologram with the Bessel–Gaussian beam. The quality of the reconstructed holographic image is increased, and the security is enhanced. Additionally, the anti-interference property is improved owing to its self-healing property of the Bessel-OAM holography.

关键词： orbital angular momentum holography Bessel–Gaussian beam OAM-multiplexing hologram

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Performance Analysis for Intrusion Target Detection in wireless sensor networks

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电子学报(英文版) 2011年第4期20卷 725-729页

作者： FAN Gaojuan WANG Ruchuan HUANG Haiping SUN Lijuan XIAO Fu College of Computer Nanjing University of Posts and Telecommunications Nanjing Chin School of Computer and Information Engineering Henan University Kaifeng China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Ministry of Education of Jiangsu Province Nanjing China

Target detection and field surveillance are among the most prominent applications of wireless sensor networks. The quality of detection achieved by a sensor network can be quantified by evaluating the probability of detecting a mobile target crossing a sensing field. Detection probability of sensor nodes has been studied in sensor networks for many purposes such as quality of service and decision making. However, the sensing capabilities of sensors are affected by environmental factors in real deployment. This paper investigates the problem of detecting probability in a log-normal shadow fading environment. It presents an analytic method to evaluate the detection probability by at least k sensors under practical considerations. Furthermore, we also shows that shadow fading makes significant influence in detection probability compared to unit disk sensing model through extensive simulation experiments.

关键词：无线传感器网络目标检测性能分析入侵检测概率环境因素阴影衰落传感器节点

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Analysis of Satellite Interference Source Location Algorithm 7

Analysis of Satellite Interference Source Location Algorithm

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7th International Conference on Computer and communications, ICCC 2021

作者： Yan, Hui Zhao, Laiding Zhang, Gengxin Ruan, Cen 'Telecommunication and Network' National Engineering Research Center Nanjing University of Posts and Telecommunications Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Nanjing China

ISBN: (纸本)9781665409506

There are many methods and principles of satellite interference source location, but no matter which method is chosen, the positioning equation is nonlinear. Therefore, it is very important to solve the nonlinear equations accurately for the accuracy of the final positioning results. In this paper, an improved particle swarm optimization (PSO) algorithm is proposed. Based on the combination of PSO and grid search algorithm, the precision requirement is set in the iterative stop condition. When the calculation results meet the set precision, iteration can be stopped. Compared with the ordinary particle swarm optimization algorithm, the results can be obtained more quickly and accurately. © 2021 IEEE.

关键词： Satellites

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TA3C: Teaching-Oriented Adaptive Wi-Fi Authorized Access Control Based on CSI 12

TA3C: Teaching-Oriented Adaptive Wi-Fi Authorized Access Con...

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12th International Conference on Mobile Ad-Hoc and sensor networks, MSN 2016

作者： Xiao, Fu Chen, Jing Xie, Xiaohui Sun, Lijuan Wang, Ruchuan College of Computer Nanjing University of Posts and Telecommunications Jiangsu China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Jiangsu China Key Lab of Broadband Wireless Communication and Sensor Network Technology of Ministry of Education Jiangsu China

ISBN: (纸本)9781509056965

Wi-Fi has been widely deployed with the rapid development of wireless communication technique. Wi-Fi hotspots are popular in campus, making convenient wireless network access possible. However, during class teaching, in order to avoid students browsing the web based on Wi-Fi hotspots and distracting, we hope Wi-Fi hotspots adaptively shield network access to students in the classroom, while grant access to users outside the classroom. In this work, we prototype TA3C system, a teaching-oriented adaptive Wi-Fi authorized access control scheme, using Channel State Information (CSI) to locate instead of coarse-grained and temporally unstable Received Signal Strength Indication (RSSI). CSI can distinguish multipath signals, stay stable in the same propagation environment, and show different characteristics in different propagation environments, based on which, we can distinguish outdoor and indoor environments, and identify user's location to decide whether to offer him wireless network access or not. Experiment results show that TA3C effectively achieve adaptive Wi-Fi authorized access control, which provides a guarantee for the quality of class teaching. Compared to traditional indoor localization techniques, TA3C does not need accurate location information but simply recognizes user's location indoors or outdoors, which means it does not need dedicated hardware, realizing the low-cost indoor localization technique. © 2016 IEEE.

关键词： Access control

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Resource allocation algorithm for uplink OFDMA-based cognitive radio systems

Resource allocation algorithm for uplink OFDMA-based cogniti...

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2011 IEEE 3rd International Conference on communication Software and networks, ICCSN 2011

作者： Wang, Yanping Yang, Longxiang Liu, Xu Jiangsu Key Lab of Wireless Communications Nanjing University of Posts and Telecommunications Nanjing China Key Lab of Broadband Wireless Communications and Sensor Network Technology Nanjing China

ISBN: (纸本)9781612844855

This context addresses the subcarrier and power allocation problem in the uplink of an OFDMA system under the cognitive radio environment. The objective is to maximize the sum transmission rate of secondary users, without causing adverse interference to the primary users. We formulate the optimization problem subject to the individual power constraints and the interference constraints. We also propose two suboptimal power loading algorithms that are less complex and a new subcarrier allocation algorithm. The performance of the optimal scheme is compared with the performance of the suboptimal. Simulation results show that the optimal algorithm significantly improves the sum transmission rate, and provides good convergence. © 2011 IEEE.

关键词： Cognitive radio

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A camera self-calibration method based on dual constraints of multi-view images

A camera self-calibration method based on dual constraints o...

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2011 International Conference on wireless communications and Signal Processing, WCSP 2011

作者： Liu, Feng Han, Weiwei Xu, Qiong Lin, Qiongjie Fan, Jingjing Image Processing and Image Communication Jiangsu Key Laboratory Nanjing China Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (纸本)9781457710100

Camera calibration is the essential step of obtaining 3D information from 2D views in the field of computer vision, which is widely used in the area of 3D reconstruction, navigation, visual supervision, etc. A camera self-calibration method based on dual constraints of multi-view images is proposed to make calibration possible when there is no reference calibration block or the movement of camera is arbitrary. In this method, multi-view images are preprocessed first to select three images which are most suitable for camera self-calibration, then we use the method based on the genetic algorithm, the camera parameters are finally estimated by using epipolar geometry matching error and reprojection error as fitness functions as two steps. Experimental results show that the proposed camera self-calibration method is correct and effective. © 2011 IEEE.

关键词： Genetic algorithms

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Stochastic Dynamic Modeling of Rain Attenuation: A Survey

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China communications 2018年第3期15卷 220-235页

作者： Zhicheng Qu Gengxin Zhang Haotong Cao Jidong Xie College of Telecommunications and Information Engineering Nanjing University of Posts and Telecommunications Satellite & Mobile communication Section Nanjing University of Posts and Telecommunications National Local Joint Engineering Research Center for communication and network technology Nanjing University of Posts and Telecommunications Key Laboratory of Broadband Wireless Communication and Sensor Network Technique of Ministry of Education Nanjing University of Posts and Telecommunications

Satellite communication systems(SCS) operating on frequency bands above 10 GHz are sensitive to atmosphere physical phenomena, especially rain attenuation. To evaluate impairments in satellite performance, stochastic dynamic modeling(SDM) is considered as an effective way to predict real-time satellite channel fading caused by rain. This article carries out a survey of SDM using stochastic differential equations(SDEs) currently in the literature. Special attention is given to the different input characteristics of each model to satisfy specific local conditions. Future research directions in SDM are also suggested in this paper.

关键词： stochastic dynamic modeling rainattenuation time-series synthesizer satellitecommunication satellite link stochastic dif-ferential equations

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ENERGY EFFICIENT DISTRIBUTED STEGANOGRAPHY FOR SECURE communication IN wireless MULTIMEDIA sensor networkS

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Journal of Electronics(China) 2013年第1期30卷 9-16页

作者： Lin Qiaomin Wang Ruchuan Ye Ning Wang Zhongqin College of Computer Nanjing University of Posts and Telecommunications Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Ministry of Education Department of Information Science Nanjing College for Population Management

A secure communication mechanism is necessary in the applications of wireless Multimedia sensor networks (WMSNs), which is more vulnerable to security attacks due to the presence of multimedia data. Additionally, given the limited technological resources (in term of energy, computation, bandwidth, and storage) of sensor nodes, security and privacy policies have to be combined with energy-aware algorithms and distributed processing of multimedia contents in WMSNs. To solve these problems in this paper, an energy efficient distributed steganography scheme, which combines steganography technique with the concept of distributed computing, is proposed for secure communication in WMSNs. The simulation results show that the proposed method can achieve considerable energy efficiency while assuring the communication security simultaneously.

关键词： Discrete Wavelet Transform （DWT） Distributed steganography Energy efficiency Perfect hash wireless Multimedia sensor networks （WMSNs）

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PASS: An adaptive multi-copy routing scheme for intermittently connected mobile Ad Hoc networks

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Journal of Convergence Information technology 2012年第14期7卷 315-323页

作者： Xu, Jia Wang, Ru Chuan Sun, Li Juan College of Computer Nanjing University of Posts and Telecommunications Nanjing China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Jiangsu Province Nanjing China Key Laboratory for Computer Network and Information Integration Southeast University Ministry of Education Nanjing China State Key Lab. for Novel Software Technology Nanjing University Nanjing China

Intermittently Connected Mobile Ad Hoc networks (ICMANs) are mobile networks in which complete source-to-destination paths do not exist most of the time. This paper proposed a Predictable Adaptive Seed Spray routing (PASS) for intermittently connected mobile Ad Hoc networks. PASS is a cost-efficient delay-bounded routing protocol without network parameters and provides acceptable and resilient service in the face of challenged environments. Simulations have shown that PASS outperforms existing schemes such as Epidemic, binary spray & wait and AMR with respect to routing cost and adaptability.

关键词： Routing protocols

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QoE oriented intelligent online learning evaluation technology in B5G scenario

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Digital communications and networks 2024年第1期10卷 7-15页

作者： Mingzi Chen Xin Wei Peizhong Xie Zhe Zhang School of Communications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology(Nanjing University of Posts and Telecommunications) Ministry of EducationNanjing210003China Institute of Higher Education Nanjing University of Posts and TelecommunicationsNanjing210003China

Students'demand for online learning has exploded during the post-COvID-19 pandemic ***,due to their poor learning experience,students'dropout rate and learning performance of online learning are not always *** technical advantages of Beyond Fifth Generation(B5G)can guarantee a good multimedia Quality of Experience(QoE).As a special case of multimedia services,online learning takes into account both the usability of the service and the cognitive development of the *** that affect the Quality of Online Learning Experience(OL-QoE)become more *** get over this dilemma,we propose a systematic scheme by integrating big data,Machine Learning(ML)technologies,and educational psychology ***,we first formulate a general definition of OL-QoE by data analysis and experimental *** formula considers both the subjective and objective factors(i.e.,video watching ratio and test scores)that most affect ***,we induce an extended layer to the classic Broad Learning System(BLS)to construct an Extended Broad Learning System(EBLS)for the students'OL-QoE *** the extended layer can increase the width of the BLS model and reduce the redundant nodes of BLS,the proposed EBLS can achieve a trade-off between the prediction accuracy and computation ***,we provide a series of early intervention suggestions for different types of students according to their predicted OL-QoE *** timely interventions,their OL-QoE and learning performance can be *** results verify the effectiveness oftheproposed scheme.

关键词： B5G Online learning Quality of experience

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