检索结果-内蒙古大学图书馆

A Time-Aware Dynamic Service Quality Prediction Approach for Services

Tsinghua Science and Technology 2020年第2期25卷 227-238页

作者： Ying Jin Weiguang Guo Yiwen Zhang Department of Management Hefei UniversityHefei 230601China School of Computer Science and Technology and also with the Key Laboratory of Intelligent Computing and Signal ProcessingMinistry of EducationAnhui UniversityHefei 230601China

Dynamic Quality of Service(QoS)prediction for services is currently a hot topic and a challenge for research in the fields of service recommendation and *** paper addresses the problem with a Time-aWare service Quality Prediction method(named TWQP),a two-phase approach with one phase based on historical time slices and one on the current time *** the first phase,if the user had invoked the service in a previous time slice,the QoS value for the user calling the service on the next time slice is predicted on the basis of the historical QoS data;if the user had not invoked the service in a previous time slice,then the Covering Algorithm(CA)is applied to predict the missing *** the second phase,we predict the missing values for the current time slice according to the results of the previous phase.A large number of experiments on a real-world dataset,WS-Dream,show that,when compared with the classical QoS prediction algorithms,our proposed method greatly improves the prediction accuracy.

关键词： dynamic Quality of Service(QoS)prediction time-aware service recommendation

来源：评论

学校读者我要写书评

暂无评论

An Anti-Eavesdrop Transmission Scheduling Scheme Based on Maximizing Secrecy Outage Probability in Ad Hoc Networks

引用

China Communications 2016年第1期13卷 176-184页

作者： WANG Yajun LIAO Tongqing WANG Chuanan School of Mathematical and Information Engineering Anhui Science and Technology University Ministry of Educational Key Laboratory of Intelligent Computing and Signal Processing Anhui University

In this paper,we consider a wireless ad hoc network consisting of multiple source nodes transmitting to their respective destinations,where an eavesdropper attempts to intercept their *** propose an optimal transmission scheduling scheme to defend against the eavesdropper,where a source node having the highest secrecy rate is scheduled to access the wireless medium for transmitting to its destination in an opportunistic *** be specific,the secrecy rate between a pair of the source and destination in the presence of an eavesdropper varies temporally due to the wireless fading *** proposed optimal transmission scheduling scheme opportunistically selects a source node with the highest secrecy rate to transmit its data for the sake of maximizing the security of the ad hoc network against eavesdropping *** comparison purposes,we also consider the conventional round-robin scheduling as a benchmark,where multiple source nodes take turns in accessing their shared wireless medium for transmitting to their respective *** derive closed-form secrecy outage probability expressions of both the round-robin scheduling and the proposed optimal scheduling schemes over Rayleigh fading *** results show that the proposed transmission scheduling scheme outperforms the conventional round-robin method in terms of its secrecy outage ***,upon increasing the number of source-destination pairs,the secrecy outage probability of the round-robin scheme keeps unchanged,whereas the secrecy outage performance of the proposed transmission scheduling significantly improves,showing the security benefits of exploiting transmission scheduling for protecting wireless ad hoc networks against eavesdropping.

关键词： transmission scheduling eavesdropping secrecy outage probability secrecy rate rayleigh fading

来源：评论

学校读者我要写书评

暂无评论

An effective method using duty cycles for assessment of exposure to mobile communication systems

引用

IEEE Electromagnetic Compatibility Magazine 2019年第2期8卷 57-63页

作者： Yang, Wanchun Zhou, Kai Tan, Pingan Gao, Xieping College of Information Engineering Key Laboratory of Intelligent Computing Information Processing of Education Ministry Xiangtan University China

An effective method for assessment of exposure to the electric field of the wireless signals from mobile communication systems is still lack, since the transmission of wireless signals is related to the traffic and the exposure level varies with the traffic load. In this paper we study the allocation mechanism of the traffic time slots in the mobile communication systems, and analyze the probability of the number of simultaneously occupied traffic time slots. Based on the queuing theory, the duty cycle of the wireless signal can be calculated by the traffic load. We establish the theoretical relationship between the exposure level and the traffic load. The exposure level in a certain period can be directly extrapolated by the calculated duty cycle, and the maximum electric field measured in the max-hold mode. By this method the maximum electric field only needs to be measured one time. Much effort on measurement can be avoided. © 2012 IEEE.

关键词： Electromagnetic fields

来源：评论

学校读者我要写书评

暂无评论

Research on the transmission enhancement properties of a novel subwavelength grating structure and mechanism

Research on the transmission enhancement properties of a nov...

引用

AASRI International Conference on Applied Engineering Science, ICAES 2014

作者： Chang, H.X. Li, M.Q. Zhang, S. Ding, Y. Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei China

ISBN: (纸本)9781138026490

The subwavelength metal grating is designed and simulated by using the finite difference time domain (FDTD) algorithm. The transmission characteristics of subwavelength metal grating structure are studied based on the Lossy Drude dispersive medium model. The influence of grating geometry parameters on the transmission characteristics are analyzed, especially for the zero transmission point location of the spectrum. The difference between the designed and conventional gratings is that the former introduces the resonant cavity. Results show that, compared with the single-layer grating, the triple-layer grating has a better filtering effect, and the transmission spectrum peak is in excess of 82%. It concludes that the transmission peak drift is analyzed by using the waveguide Fabry-Perot (F-P) cavity resonance effect, and the zero transmission point location of the spectrum is independent of the metal layer thickness. The influence rules provide an available reference for the design of the band-pass filters. © 2015 Taylor & Francis Group, London.

关键词： Bandpass filters

来源：评论

学校读者我要写书评

暂无评论

Research on solving time-dependent Schrodinger equation for higher-order FDTD based on spatial filtering

Research on solving time-dependent Schrodinger equation for ...

引用

2023 International Applied Computational Electromagnetics Society Symposium, ACES-China 2023

作者： Ding, Wenjie Xie, Guoda Huang, Zhixiang Ministry of Education The Key Laboratory of Intelligent Computing and Signal Processing Hefei China Hefei China

ISBN: (纸本)9781733509657

Combining the spatial filtering (SF) technique with FDTD(2, q) method (2 and q denote the temporal differential order and spatial differential order, respectively), a novel SF-FDTD(2, q) method with more relaxed Courant-Friedrichs-Lewy (CFL) condition is proposed and used for solving 3D time-dependent Schrödinger equation. Then, the correctness of the SF-FDTD(2, q) method is validated by calculating eigenfrequencies of the 3D quantum well model. © 2023 Applied Computational Electromagnetics Society (ACES).

关键词： Computational electromagnetics

来源：评论

学校读者我要写书评

暂无评论

Fast Near-field Computational Imaging with Deep Neural Networks

Fast Near-field Computational Imaging with Deep Neural Netwo...

引用

2021 CIE International Conference on Radar, Radar 2021

作者： Zhao, Fafa Wu, Zhenhua Pan, Xueli Yang, Lixia Ministry of Education Anhui University Key Laboratory of Intelligent Computing and Signal Processing Hefei China

ISBN: (纸本)9781665498142

With the capability to sculpt complex radiative wavefronts and couple energy from the reference wave to the desired radiation pattern, metasurface antennas have gained tremendous progress in recent years. The flexibility in antenna design gives rise to a bunch of metasurface antennas, while there is still a comprise between the needed operation band and radiation field pattern coherence. Furthermore, the relatively low sampling ratio and overlap between frequency measurement modes would inevitably pose a great challenge for matched filter and other advanced sparsity-driven post-processing imaging algorithms. In this paper, we design a deep neural network to achieve fast scene image reconstruction. The trained network could fastly reconstruct the imaged object in both low scene compressed ratio and high coherence of the measurement modes. The imaging experiments with measured radiation field data are conducted to verify the effectiveness of our method. © 2021 IEEE.

关键词： computational imaging deep neural network metasurface antennas

来源：评论

学校读者我要写书评

暂无评论

A Wideband Millimeter-wave Bidirectional OAM Antenna using sequential rotation feeding 4

A Wideband Millimeter-wave Bidirectional OAM Antenna using s...

引用

4th International Applied Computational Electromagnetics Society Symposium in China, ACES-China 2021

作者： Wu, Jie Feng, Jian Huang, Zhixiang Wu, Xianliang Key Laboratory of Intelligent Computing Signal Processing Anhui University Ministry of Education Hefei China

ISBN: (纸本)9781733509619

A wideband bidirectional circularly polarized (CP) orbital angular momentum (OAM) antenna array is proposed for millimeter-wave frequency. The designed antenna array is composed of four bidirectional radiating dual-CP antenna units that rotate 90 degrees sequentially to each other in the clockwise direction. Results indicate that the left-hand circular polarization (LHCP) with a mode l-{OAM}=-1 in +z direction and right-hand circular polarization (RHCP) with a mode l-{OAM}=+1 in -z direction, over a wide impedance and 3-dB axial ratio (AR) relative bandwidth of 32.3% from 26 to 36 GHz. © 2021 Applied Computational Electromagnetics Society (ACES).

关键词： Antenna arrays

来源：评论

学校读者我要写书评

暂无评论

Numerical simulation of infrared photodetectors with Au gratings by FDFD method 6

Numerical simulation of infrared photodetectors with Au grat...

引用

6th IEEE International Symposium on Microwave, Antenna, Propagation, and EMC Technologies, MAPE 2015

作者： Lulu, Cheng Huang, Zhixiang Xu, Jie Wu, Xianliang Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei China

ISBN: (纸本)9781467374415

Quantum-well infrared photodetectors have been studied extensively due to their night vision, astronomy and environmental monitoring research in recent years. However, responsivity and detectivity are relatively low in these photodetectors without the Au gratings. Therefore, the Au grating will be employed on the surface of photodetector with periodic structure due to the principle of spoof plasmon resonance. The new design mainly aims to enhance the absorption in the QW active region based on the Au grating and can be numerically simulated by using finite-difference frequency-domain method. With optimal grating parameters, the absorption can be enhanced by hundreds of times compared with that in the reference structure without grating. The theoretical results provide the realistic organic infrared photodetectors with theoretical basis and technical support. © 2015 IEEE.

关键词： Numerical methods

来源：评论

学校读者我要写书评

暂无评论

Delay estimation in DS-CDMA communication using conjugate descent algorithm

Delay estimation in DS-CDMA communication using conjugate de...

引用

2008 International Conference on Wireless Communications, Networking and Mobile computing, WiCOM 2008

作者： Xiaohui, Li Wei, Gao Hongwei, Zhang Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei China

ISBN: (纸本)9781424421084

in this paper, we propose a method for DS-CDMA delay estimation through the use of the downlink channel character. This method is based on Independent Component Analysis using the conjugate descent algorithm to estimate the multi-path mixture matrix and find the delay information which is embodied by the column vector of the mixture matrix using both the independence of information source and the known spread spectrum code. The simulation results show that it has better estimated effect and enhance the performance of traditional detector comparing with MMSE and Fast-ICA algorithm. © 2008 IEEE.

关键词： Code division multiple access

来源：评论

学校读者我要写书评

暂无评论

Electromagnetic scattering of two-dimensional rough cylinder based on statistical integral equation 2

Electromagnetic scattering of two-dimensional rough cylinder...

引用

2020 2nd International Conference on Artificial Intelligence Technologies and Application, ICAITA 2020

作者： Zhu, Mengnan Wang, Anqi Huang, Zhixiang Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei China

The study of electromagnetic scattering from Gaussian rough surface is of great significance in radar reconnaissance, target tracking and ocean remote sensing. The moment method (MOM) is a commonly used method with high accuracy. However, in the past research, Monte Carlo method is used to simulate the Gaussian rough surface. In this method, a large number of random simulation operations are carried out, and then a statistical convergence result is obtained by counting the results of all operations. In this paper, the stochastic integral equation method SIEM(Stochastic Integral Equation Method) is proposed to calculate the electromagnetic scattering of Gaussian rough surface. SIEM avoids the difficulty of high difficulty precise modeling and repeated calculation many times, and only single modeling and calculation are carried out for the target problem. In this paper, the electromagnetic scattering of two-dimensional cylinder with Gaussian rough surface is solved, and the effectiveness of SIEM is proved by comparing with mom. © 2020 Published under licence by IOP Publishing Ltd.

关键词： Method of moments

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：