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Investigation on random access in a VLC system with multipacket reception in the presence of hidden devices and obstructions

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Optoelectronics Letters 2016年第6期12卷 455-460页

作者：蔡文静迟学芬赵琳琳 college of communication Engineering Jilin University

Due to the directionality of light, the hidden device problem and the obstruction cannot be ignored for carrier sense multiple access with collision avoidance(CSMA/CA)-based uplink visible light communication(VLC). In this paper, we introduce multipacket reception(MPR) to handle the hidden device problem in VLC system. We model the traffic of the device with on/off Markov source. With the unsaturated traffic, we formulate a two dimensional(2D) Markov chain to model the CSMA/CA-based slotted random access procedure to evaluate the effects of hidden devices and obstructions on the performance of MPR-aided VLC system, which are mapped into the transition probabilities of the Markov chain. Then, we analyze the throughput and the reception power efficiency(RE) of MPR-aided VLC system with the obstructed optical channel. Numerical results show that the effect is negative when hidden devices or obstructions appear solely. But when they appear simultaneously, they will interact with each other to mitigate the negative effects.

关键词： hidden CSMA throughput collision obstruction interact solely traffic handle aided

Membrane-inspired quantum bee colony optimization and its applications for decision engine

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Journal of Central South University 2014年第5期21卷 1887-1897页

作者：高洪元李晨琬 college of Information and communication Engineering Harbin Engineering University

In order to effectively solve combinatorial optimization problems,a membrane-inspired quantum bee colony optimization(MQBCO)is proposed for scientific computing and engineering *** proposed MQBCO algorithm applies the membrane computing theory to quantum bee colony optimization(QBCO),which is an effective discrete optimization *** global convergence performance of MQBCO is proved by Markov theory,and the validity of MQBCO is verified by testing the classical benchmark *** the proposed MQBCO algorithm is used to solve decision engine problems of cognitive radio *** hybridizing the QBCO and membrane computing theory,the quantum state and observation state of the quantum bees can be well evolved within the membrane *** results for cognitive radio system show that the proposed decision engine method is superior to the traditional intelligent decision engine algorithms in terms of convergence,precision and *** experiments under different communication scenarios illustrate that the balance between three objective functions and the adapted parameter configuration is consistent with the weights of three normalized objective functions.

关键词： quantum bee colony optimization membrane computing P system decision engine cognitive radio benchmarkfunction

Wideband Signal Detection Based on MWC Discrete Compressed Sampling Structure

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Transactions of Nanjing University of Aeronautics and Astronautics 2017年第2期34卷 105-114页

作者： Chen Tao Liu Lizhi Guo Limin college of Information and communication Engineering Harbin Engineering University

In order to solve the cross-channel signal problem caused by the uniform channelized wideband digital receiver when processing wideband signal and the problem that the sensitivity of the system greatly decreases when the bandwidth of wideband digital receiver increases,which both decrease the wideband radar signal detection performance,a new wideband digital receiver based on the modulated wideband converter(MWC)discrete compressed sampling structure and an energy detection method based on the new receiver are ***,the proposed receiver utilizes periodic pseudo-random sequences to mix wideband signals with baseband and other *** the mixed signals are low-pass filtered and downsampled to obtain the baseband compressed sampling data,which can increase the sensitivity of the ***,the cross-channel signal will all appear in any subbands,so the cross-channel signal problem can be solved easily by processing the baseband compressed sampling ***,we establish the signal detection model and formulate the criterion of the energy detection *** we directly utilize the baseband compressed sampling data to carry out signal detection without signal reconstruction,which decreases the complexity of the algorithm and reduces the computational ***,simulation experiments demonstrate the effectiveness of the proposed receiver and show that the proposed signal detection method is effective in low signal-to-noise ratio(SNR)compared with the conventional energy detection and the probability of detection increases significantly when SNR increases.

关键词： wideband digital receiver cross-channel signal modulated wideband converter(MWC) compressed sampling energy detection

High Frequency communication Network with Diversity: System Structure and Key Enabling Techniques

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China communications 2018年第9期15卷 46-59页

作者： Kun Xu Bin Jiang Zeyou Su Shengqing Wang Makun Guo Xiao Li Zhiyong Du college of Information and communication National University of Defense Technology

High frequency sky wave communication suffers from poor performance including poor link quality and low link success rate. To enhance performance, diversity technology is proposed in the high frequency communication network(HFCN) in this ***, we present the benefits and the challenges by introducing diversity technology into the existing HFCN. Secondly, to exploit the benefits fully and overcome the challenges, we propose a system structure suitable for deploying diversity technology in HFCN in large scale,based on the cloud radio access network and software defined network. Moreover, we present a general structure for the real-time updating frequency management system that plays a more important role especially when resource consuming(e.g., frequency) diversity technology is deployed. Thirdly, we investigate the key techniques enabling diversity technology deployment. Finally, we point out the future research directions to help the HFCN with diversity work more efficiently and intelligently.

关键词： high frequency high frequency communication network diversity technology access layer and core layer frequency management system

Atmospheric corrosion mapping of copper surfaces from diffuse light scattering measurements by an optoelectronic sensor system

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 613-618页

作者： Marimuthu PAULVANNA NAYAKI Arunachalam P.KABILAN Department of Electronics and communication Engineering PSNA College of Engineering and TechnologyDindigul 624622 India Department of Electronics and communication Engineering Chettinad College of Engineering and TechnologyKarur 639114 India

A novel light scattering technique for mapping metal surface corrosion is presented and its results on copper exposed to atmosphere are reported. The front end of the instrument is made up of a sensor module comprising a thin beam light emitting diode (LED) illuminating a small spot on the metal surface, and a matched pair of photodetectors, one for capturing the reflected light and the other for sampling the scattered light. The analog photocurrent signals are digitized and processed online by a personal computer (PC) to determine the corrosion factor defined in terms of the two current values. By scanning the sample surface using the light beam and by computing the corrosion factor values simultaneously, a three dimensional graph and a two dimensional contour map are generated in the PC using Matlab tools. The values of the corrosion factor measured in different durations of exposure to atmosphere, which obey a bilogarithmic law, testify to the validity of our mathematical model.

关键词： Light scattering Optoelectronic sensor Atmospheric corrosion mapping

Learning Association Rules and Tracking the Changing Concepts on Webpages:An Effective Pornographic Websites Filtering Approach

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Journal of Electronic Science and Technology 2018年第1期16卷 24-36页

作者： Jyh-Jian Sheu college of communication National Chengchi UniversityTaipei 11605

We applied the decision tree algorithm to learn association rules between webpage’s category(pornographic or normal) and the critical *** on these rules, we proposed an efficient method of filtering pornographic webpages with the following major advantages: 1) a weighted window-based technique was proposed to estimate for the condition of concept drift for the keywords found recently in pornographic webpages; 2) checking only contexts of webpages without scanning pictures; 3) an incremental learning mechanism was designed to incrementally update the pornographic keyword database.

关键词： Concept drift data mining decision tree pornographic websites filtering

A low voltage and small hysteresis C_(60) thin film transistor

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Journal of Semiconductors 2011年第2期32卷 48-52页

作者：周建林陈仁钢 Department of Electronic Engineering College of Communication and ElectronicsChongqing University

Organic thin film transistors with C6O as an n-type semiconductor have been fabricated. A tantalum pentoxide （Ta2O5）/poly-methylmethacrylate （PMMA） double-layer structured gate dielectric was used. The Ta2O5 layer was prepared by using a simple solution-based and economical anodization technique. Our results demonstrate that double gate insulators can combine the advantage of Ta2O5 with high dielectric constant and polymer insulator for a better interface with the organic semiconductor. The performance of the device can be improved obviously with double gate insulators, compared to that obtained by using a single Ta205 or PMMA insulator. Then, a good performance n-type OTFT, which can work at 10 V with mobility, threshold voltage and on/off current ratio of, respectively, 0.26 cm2/（V.S）, 3.2 V and 8.31 × 10^4, was obtained. Moreover, such an OTFT shows a negligible ＂hysteresis effect＂ contributing to the hydroxyl-free insulator surface.

关键词： organic thin film transistors C60 double gate dielectrics

Modeling and simulation of centroid and inversion charge density in cylindrical surrounding gate MOSFETs including quantum effects

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Journal of Semiconductors 2013年第11期34卷 25-30页

作者： P.Vimala N.B.Balamurugan Department of Electronics and communication Engineering Thiagarajar College of Engineering

An analytical model for surrounding gate metal-oxide-semiconductor field effect transistors （MOS- FETs） considering quantum effects is presented. To achieve this goal, we have used a variational approach for solving the Poisson and Schrodinger equations. This model is developed to provide an analytical expression for the inversion charge distribution function for all regions of the device operation. This expression is used to calculate the other important parameters like the inversion charge centroid, threshold voltage and inversion charge density. The calculated expressions for the above parameters are simple and accurate. The validity of this model was checked for the devices with different device dimensions and bias voltages. The calculated results are compared with the simulation results and they show good agreement.

关键词： surrounding gate MOSFETs energy quantization centroid inversion charge density

Improved Conditions for Global Asymptotic Stability of Cohen-Grossberg Neural Networks with Time-Varying Delays

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Chinese Physics Letters 2008年第11期25卷 3894-3897页

作者：陈君崔宝同高明 college of communication and Control Engineering Jiangnan University Wuxi 214122

The global asymptotic stability of delayed Cohen-Grossberg neural networks with impulses is investigated. Based on the new suitable Lyapunov functions and the Jacobsthal inequality, a set of novel sufficient criteria are derived for the global asymptotic stability of Cohen-Grossberg neural networks with time-varying delays and impulses. An illustrative example with its numerical simulations is given to demonstrate the effectiveness of the obtained results.

关键词： Global Asymptotic Stability of Cohen--Grossberg Neural Networks Time-Varying Delays