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arXiv 2019年

作者： Zhang, Rui Zhu, Zheng Li, Peng Wu, Rui Guo, Chaoxu Huang, Guan Xia, Hailun Bejing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China Beijing Laboratory of Advanced Information Networks Beijing Institute of Automation Chinese Academy of Sciences Beijing China Horizon Robotics Beijing

Human pose estimation has witnessed a significant advance thanks to the development of deep learning. Recent human pose estimation approaches tend to directly predict the location heatmaps, which causes quantization errors and inevitably deteriorates the performance within the reduced network output. Aim at solving it, we revisit the heatmap-offset aggregation method and propose the Offset-guided network (OGN) with an intuitive but effective fusion strategy for both two-stages pose estimation and Mask R-CNN. For two-stages pose estimation, a greedy box generation strategy is also proposed to keep more necessary candidates while performing person detection. For mask R-CNN, ratio-consistent is adopted to improve the generalization ability of the network. State-of-the-art results on COCO and PoseTrack dataset verify the effectiveness of our offset-guided pose estimation and tracking. Copyright © 2019, The Authors. All rights reserved.

关键词： Deep learning

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Ultra-broadband Polarization Rotator Design in Terahertz Region

Ultra-broadband Polarization Rotator Design in Terahertz Reg...

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International Conference on Wireless Communications and Signal Processing (WCSP)

作者： Weijun Hong Xinlong Li Jianfeng Zhu Shufang Li Tingxiao Cai Huanhuan Lin Hongjie Liu Yanqing Wei Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China Beijing Laboratory of Advanced Information Network Beijing University of Posts and Telecommunications Beijing China China Electronics Standardization Institute Beijing China Borsche Technologies Limited Company Beijing China Renmin University of China Beijing China

A three layered metamaterial functions as polarization rotator with extremely broad bandwidth and high conversion ratio is proposed and investigated in this paper. The designed structure is composed of two electric dipole resonant polarization selectors on the top and bottom sides and a cross-shaped polarization converter in the middle filled with two dielectric layers of silica as spacers. The proposed structure forms a cascaded Fabry-Perot-like resonance cavity, leading to the enhancement of polarization conversion between two orthogonal linearly polarized waves. The designed structure is optimized to achieve an extremely broad bandwidth, sharp rejection stop-band, and maximum conversion ratio of 99.9% at the resonant frequency.

关键词： Metamaterials Cavity resonators Polarization Bandwidth Substrates Telecommunications Dielectrics

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Dynamic backoff based access mechanism for LoRaWAN class A 2

Dynamic backoff based access mechanism for LoRaWAN class A

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2nd IEEE International Conference on Energy Internet, ICEI 2018

作者： Yuan, Pengyu Wen, Xiangming Lu, Zhaoming Pan, Qi Beijing Key Laboratory of Network System Architecture and Covergence Beijing University of Posts and Telecommunications Beijing Laboratory of Advanced Information Networks Beijing China

ISBN: (纸本)9781538641316

LoRaWAN is a popular technology in Low Power Wide Area networks(LPWANs). It can be applied to the smart agriculture, smart building, logistics tracking, disaster monitoring, and so on. The Class A terminal device in LoRaWAN adopts the pure ALOHA access mode. It has the problems of low channel utilization, high access delay and high collision probability. In this paper, we mainly study the access process of Class A devices in LoRaWAN, and derive the mathematical analytical model. To solve this problem, we propose a enhanced access mechanism, dynamic backoff mechanism. The backoff window size would be adaptively adjusted according to the access user attempts. The results show that our model is correct and the proposed scheme can effectively improve the successful access probability for LoRaWAN nodes. © 2018 IEEE.

关键词： Probability

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Energy Consumption Optimization Scheme of Cloud Data Center Based on SDN

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Procedia Computer Science 2018年 131卷 1318-1327页

作者： Qing Liao Zun Wang Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

In response to the mobile Internet, Internet of things and cloud computing technology fast development, the operation of large-scale distributed computing cloud data center construction in the world at the same time, the network data calculation of energy consumption problem is causing extensive concern. And the software-defined network (SDN) provides a feasible solution to the rigid problem of traditional network architecture. Based on SDN technology, this paper proposes a method of energy consumption control based on cloud data center. Aiming at server energy saving, the multi-objective optimization model of virtual machine migration integration is established, and the integration mechanism of virtual machine migration based on mixed single-parent genetic algorithm is proposed. The experimental results show that the algorithm can be used to solve the problem of virtual machine migration and integration in data center.

关键词： Cloud data center software-defined network energy consumption control VM migration integration

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Generative Model with Kernel Density Estimation

Generative Model with Kernel Density Estimation

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IEEE International Conference on network Infrastructure and Digital Content (IC-NIDC)

作者： Jing Tan Sixing Yin Shuo Zhao Beijing Key Laboratory of Network System Architecture and Convergence Beijing China

In this paper, a novel generative model is proposed based on kernel density estimation. Different from other generative models like GANs [1] and VAEs [2], the model directly learns the distribution of training dataset in a non-parametric way. The mean absolute error (MAE) between the estimated probability density of the real and generated samples is used as loss function for model to train. To address the sparsity of high-dimensional distribution, we associate the proposed generative model with an encoder, by which the observed high-dimensional data can be transformed to low-dimensional latent features. Results on the MNIST dataset show that our proposed model is able to generate samples visually indistinguishable from the real ones.

关键词： Kernel Estimation Training Generators Training data Gallium nitride Bandwidth

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Markov chain based on path selection in the heterogeneous internet of things model 2

Markov chain based on path selection in the heterogeneous in...

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2nd IEEE International Conference on Energy Internet, ICEI 2018

作者： Wu, Huan Wen, Xiangming Lu, Zhaoming Huang, Shuyang Beijing Key Laboratory of Network System Architecture and Convergence Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications Beijing100876 China School of Electronics and Information Engineering West Anhui University Lu'an237012 China

ISBN: (纸本)9781538641316

The Internet of Things (IoT) is a new heterogeneous system integrated by various end-users with different technologies. However, the limiting factor is bandwidth in the IoT due to exploding the end-users and the network bandwidth requirement. A novel IoT model, which integrates the Power Line Carrier (PLC) and the Wireless network (WN), is proposed to solve the bandwidth problem from the architecture, especially in the areas lacking network facilities. In addition, we exploit an effective virtual layer (EVL) which allows the different end-users access to the model seamlessly. Then, the attractor selection algorithm based on Markov chain (ASMA) is employed to select an optimal path among the PLC or the WN. Simulation results demonstrate that the proposed model has the smaller delay than other algorithms and makes the model more stable. © 2018 IEEE.

关键词： Internet of things

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A Compact Broadband Filter Using Triple-Mode Stepped-Impedance Stub-Loaded Resonator

A Compact Broadband Filter Using Triple-Mode Stepped-Impedan...

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2018 IEEE International Conference on Computational Electromagnetics, ICCEM 2018

作者： Li, Mingxing Wu, Yongle Qu, Meijun Liu, Yuanan Beijing University of Posts and Telecommunications State Key Laboratory of Information Photonics and Optical Communications School of Electronic Engineering Beijing China Sch. of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence Beijing China

ISBN: (纸本)9781538612415

In this paper, a compact broadband bandpass filter (BPF) using triple-mode stepped-impedance stub-loaded resonator (TMSISLR) is proposed. The TMSISLR is composed of an impedance-transforming unit and two asymmetrical open-ended stepped-impedance stubs (SIS) at the center. By simply adjusting the impedances of the SIS, the resonant frequencies of the TMSISLR can be flexibly changed. The interdigital coupled-lines are adopted to feed the proposed TMSISLR. This BPF can realize wide bandwidth, low insertion loss, high selectivity, and deep stopband rejection simultaneously. Finally, the proposed BPF is simulated, fabricated, and measured. The measured results show that the impedance bandwidth under-16.7 dB is 86% from 1.89 to 4.75 GHz, while the insertion loss is smaller than 1.47 dB. The measured insertion loss is larger than 30 dB at both low-and upper-stopband (from 0 to 1.27 GHz and 6.03 to 7.66 GHz). The measured results are in good agreement with the simulated counterpart. © 2018 IEEE.

关键词： Bandpass filters

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Terajet effect of dielectric sphere and THz imaging 5

Terajet effect of dielectric sphere and THz imaging

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Infrared, Millimeter-Wave, and Terahertz Technologies V 2018

作者： Qu, Qingshan Liu, Hailing Zhu, Di Yang, Menghan Cui, Bin Feng, Shuai Yang, Yuping School of Science Minzu University of China Beijing100081 China Beijing Laboratory of Advanced Information Networks Beijing Key Laboratory of Network System Architecture and Convergence Acknowledgment School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing100876 China

ISBN: (数字)9781510622517

ISBN: (纸本)9781510622500

Analogous to microsphere optical nanoscope, an easy and low-price method of THz imaging is proposed and developed for improving the spatial resolution beyond the diffraction limit. By attaching a 2-4 mm diameter Teflon sphere, a narrow, high-intensity, subdiffraction-waist THz beam with a strong jet-like distribution propagates into the background medium from the sphere's shadow-side surface and a subwavelength spatial resolution better than λ/3 is demonstrated. Furthermore, the dielectric sphere-coupled THz microscope not only enables far-field, large-area measurement but also characterizes high-throughput and broad-band imaging properties. In addition, the size effect on terajet of dielectric sphere was simulated and shows that its magnification capability and focal length are size-dependent and frequencysensitive. © 2018 SPIE.

关键词： Spheres

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Transmission Capacity Analysis for Linear VANET under Physical Model

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China Communications 2017年第3期14卷 97-107页

作者： Xinxin He Hang Zhang Weisen Shi Tao Luo Norman C.Beaulieu Beijing Laboratory of Advanced Information Networks Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

In this study, the transmission capacity of VANETs in a highway scenario is analysed on the basis of a 1D line model and the carrier sense multiple access with collision avoidance(CSMA/CA) protocol. We describe the CSMA/CA protocol used in IEEE802.11 p from the perspective of the geometric relationship amongst simultaneous transmitters. The desired channel and interfering channels are assumed to experience the same amount of path-loss and Rayleigh fading. On the basis of the proposed model, we analyse the attempted transmission probability of each road segment and the maximum intensity of active transmitters, including their theoretical values. Then, we employ the physical model to obtain the outage probability and derive the upper bound of the transmission capacity of a VANET, which is defined as the average spatial density of successful transmissions in the network. Simulation results indicate that the theoretical value offers a good bound on network capacity.

关键词： VANET transmission capacity line model CSMA/CA

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A robust fractal tag antenna for UHF RFID 4

A robust fractal tag antenna for UHF RFID

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4th IEEE International Conference on Computer and Communications, ICCC 2018

作者： Dong, Yaru Hong, Weijun Li, Shufang Uddin, Shahab Liu, Hongjie Chen, Deken Beijing Laboratory of Advanced Information Networks Beijing Key Laboratory of Networks System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China Beijing Borsche Technologies Co Ltd. Beijing China

ISBN: (纸本)9781538683392

To improve the robustness of the RFID tag antenna for consumer-level application, this paper presents a UHF RFID antenna based on the characteristics of the tree-liked fractal. The paper exhibits a broad bandwidth with a resonance frequency locating at 900 MHz and the -10dB relative impedance bandwidth is 25% (630MHz-1050MHz). The radiation of the antenna is also pretty good with omnidirectional and a maximum gain of 3.24 dBi on its boresight. More importantly, the proposed antenna can maintain the good matching and radiation performance even large areas of the antenna surface are cut out, which cannot be achieved in other RFID tag antennas such as the commonly used ALN-9640 and ALN-9654 RFID tag antennas. The fractal RFID antenna proposed in this paper outperforms other tag antennas on injury resist. This capability enables the antenna can be used in more widespread application, especially in some harsh environment. © 2018 IEEE.

关键词： Fractals

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