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11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017

作者： Xu, Peng Zhao, Xueyuan State Key Lab. of Networking and Switching Technology Beijing University of Posts and Telecommunications BUPT Xitucheng road 10 Haidian District Beijing100876 China

ISBN: (纸本)9781450348881

The rapid development of Internet brings more challenges for application providers not only on applications, but also on the development of applications. Rich-content applications have become the hottest applications in Internet and mobile Internet. In this paper, we propose a new open extensible search service SOUYA to simplify the development of rich-content applications. It provides flexible interfaces to access data. What the application developers have to deal with is just the implementation of frontend pages. The advantage of SOUYA lies in that it could increase the development efficiency. © 2017 ACM.

关键词： Cloud Open APIs Rich-content Search service

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Spin image of an atomic vapor cell with a resolution smaller than the diffusion crosstalk free distance

arXiv

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arXiv 2019年

作者： Dong, Hai-Feng Chen, Jing-Ling Li, Ji-Min Li, Chen Li, Ai-Xian Zhao, Nan Guo, Fen-Zhuo School of Instrumentation and Optoelectronic Engineering Beihang University Beijing100083 China Quantum Sensing and Information Sensing Lab Graduate School of China Academy of Engineering Physics Beijing100193 China Quantum Physics and Quantum Information Division Beijing Computational Science Research Center Beijing100193 China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing100876 China School of Science Beijing University of Posts and Telecommunication Beijing100876 China

The diffusion crosstalk free distance is an important parameter for spin images in atomic vapor cells and is also regarded as a limit on the spatial resolution. However, by modulating the pumping light both spatially and temporally using a digital micromirror device, a spin image of a vapor cell has been obtained with a distinguishable stripe width of 13.7 μm, which is much smaller than the corresponding diffusion crosstalk free distance of ∼138 μm. The fundamental limit on the spatial resolution as determined by diffusion and the uncertainty principle is analyzed. Copyright © 2019, The Authors. All rights reserved.

关键词： Crosstalk

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Dynamic Range Impact on 3D MIMO Channel Characteristics in Rural-Macro Scenario at 3.5 GHz

Dynamic Range Impact on 3D MIMO Channel Characteristics in R...

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European Conference on Antennas and Propagation

作者： Weite Zhang Lei Tian Zhongyuan Wu Jianhua Zhang Yi Zheng Jingmin Cao Key Lab of Universal Wireless Communications Ministry of Education State Key Lab of Networking and Switching Technology Beijing University of Posts and Telecommunications Mailbox NO.92 100876 Beijing China China Mobile Research Institude Beijing China National Key Laboratory of Science and Technology on Blind Signal Processing Chengdu Sichuan China

ISBN: (纸本)9781785618154;9781785618161

Rural-macro (RMa) is an important scenario for fifth generation (5G) deployment, and there is a strong diffraction in RMa making it difficult to distinguish between line-of-sight (LoS) and non-line-of-sight (NLoS) case. Since the environmental condition is closely related to the dynamic range of channel impulse response (CIR), this paper studies the dynamic range impact on characteristics of three dimensional (3D) multiple-input multiple-output (MIMO) channels based on 3.5 GHz measurement campaign in RMa. The space-alternating generalized expectation-maximization (SAGE) algorithm is employed to estimate multipath component parameters. The channel statistical characteristics, channel capacity and eigenvalues of CIR matrix are calculated for different CIR dynamic ranges. The results show that the delay spread, the angle spread, the channel capacity and the sub-channel correlation are linearly related to the dynamic range of CIR. Thus, the results give a new perspective to study channel characteristics based on CIR dynamic range in RMa scenario.

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A Novel Clustering Method Based on Density Peaks and Its Validation by Channel Measurement

A Novel Clustering Method Based on Density Peaks and Its Val...

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European Conference on Antennas and Propagation

作者： Hanqing Xue Lei Tian Yuxiang Zhang Chao Wang Jianhua Zhang Wei Li Hewen Wei Key Lab of Universal Wireless Communications Ministry of Education State Key Lab of Networking and Switching Technology Beijing University of Posts and Telecommunications P. O. Box 92 Beijing 100876 China Department of Electrical Engineering Northern Illinois University DeKalb IL 60115 National key laboratory of science and technology on blind signal processing Chengdu Sichuan 610041 China

ISBN: (纸本)9781785618154;9781785618161

In this paper, cluster centers are defined as local maxima in the density which is called density peaks. We use an algorithm based on density peaks to cluster multipath components (MPCs) whose parameters are estimated by the space-alternating generalized expectation-maximization (SAGE) algorithm. To validate its performance, we apply it to the data from a channel measurement in an indoor scenario at 28 GHz and compare it to the widely used KPowerMeans algorithm with the same distance metric of multiple component distance (MCD). Through the results, we find it can cluster MPCs more accurately validated by Calinski-Harabasz (CH) and Davies-Bouldin (DB) indices. More importantly, it overcomes the shortcoming of setting the number of clusters manually because we can determine the cluster centers automatically. Besides, the efficiency of DP clustering is far superior to KPowerMeans because what it needs is only a distance matrix and we only need to compute it once. At the end, statistical analysis of clusters are presented to provide insights in channel modeling of millimeter wave.

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MO-PR: Message-Oriented Partial-Reliability MPTCP for Real-time Multimedia Transmission in Wireless Networks

MO-PR: Message-Oriented Partial-Reliability MPTCP for Real-t...

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International Wireless Communications and Mobile Computing Conference, IWCMC

作者： Jiuren Qin Changqiao Xu Hui Huang Lujie Zhong Gabriel-Miro Muntean State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China Information Engineering College Capital Normal University Beijing China Performance Engineering Lab. School of Electronic Engineering Dublin City University Dublin Ireland

As an extension of Transmission Control Protocol (TCP), Multi-Path Transport Control Protocol (MPTCP) provides a reliable and streaming-oriented transmission service to the upper applications. However, when turning to the real-time multimedia transmission, the repeatedly retransmission of expired segments is unnecessary and inefficient. Thus, we propose a Message-Oriented Partial-Reliability (MO-PR) improvement for MPTCP in this paper. The MO-PR firstly extend the Partially-Reliability transmission scheme to MPTCP which allows the sender to abandon the invalid segment by notifying the receiver. Then, the Message-Oriented retransmission mechanism is designed to improve the discarding efficiency. Finally, the comparison-based simulation results show that MO-PR can effectively improve the transmission performance of multimedia in dynamic wireless networks.

关键词： Reliability Receivers Protocols Streaming media Wireless networks Delays Standards

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Comparative Channel Study of Ray Tracing and Measurement for an Indoor Scenario at 28 GHz

Comparative Channel Study of Ray Tracing and Measurement for...

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European Conference on Antennas and Propagation

作者： Jinnan Zhan Jianhua Zhang Lei Tian Xinzhuang Zhang Pan Tang Jianwu Dou Hewen Wei Key Lab of Universal Wireless Communications Ministry of Education State Key Lab of Networking and Switching Technology Beijing University of Posts and Telecommunications Mailbox NO.92 100876 Beijing China Wireless Algorithm Department Product R&D system ZTE Corp. Ltd. 201210 Shanghai China National Key Laboratory of Science and Technology on Blind Signal Processing 610041 Chengdu Sichuan China

The millimeter wave communication is important for future wireless systems. In this paper, the channel characteristics at 28 GHz in an indoor scenario are researched based on ray tracing (RT) simulation and measurement. In the RT simulation, various configurations, such as different number of reflections, diffractions and penetrations are used. As for the measurement, two setups are implemented in order to analyze more parameters. Setup one is that biconical antennas are used at both the transmitter (TX) and receiver (RX). The other setup is that horn antenna at RX is rotated 360° in azimuth with a step of 5° when an omni-directional antenna located at TX. Meanwhile, antenna is rotated one circle with an elevation angle of 10°, 0° and -10°, respectively. Path loss and K-factor are analyzed firstly, and analysis results indicate the RT result with 1 or 2 reflections, 1 diffractions and 5 penetrations in this conference room is closest to the measurement result and channel models in 3GPP TR 38.901. Then, the root mean square (RMS) delay spread and RMS angular spread are investigated, which shows the value of measurement is a bit larger than RT because of the limitation of azimuth and elevation step. According to all the results, 1-2 reflections, 1 diffraction and 5 penetrations can be used in RT for future analysis of indoor scenario at 28 GHz.

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A maximum data transmission rate oriented dynamic APs grouping scheme in user-centric UDN

A maximum data transmission rate oriented dynamic APs groupi...

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IEEE International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS)

作者： Bo Hu Yingying Wang Chuanan Wang State Key Lab of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing CHINA

The ultra-dense network (UDN) is considered as a promising technology for 5G. User-centric UDN (UUDN) is a wireless network that the access point (AP) density is comparable to the user density, and this network will organize a dynamic APs Group (APG) to serve each user equipment (UE) seamlessly without UE's involvement. In this paper, we propose a maximum data transmission rate oriented Dynamic APs Grouping (MDTR-DAPGing) scheme for mobility management in UUDN. In the MDTR-DAPGing scheme, the criterion of APG initiation is to maximize data transmission rate. Furthermore, the APG member will be dynamically refreshed according to the UE's movement or network environment change. Then, we introduce the application of the MDTR-DAPGing scheme for mobility management in UUDN scenarios. Compared to the legacy handover scheme, the simulations are carried out from three aspects, including interrupt ratio, UE throughput and UE weighted sum rate, which show the improvement of the MDTR-DAPGing scheme.

关键词： Signal processing Indexes Data communication

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Millimeter Wave Channel Measurements and Modelling in an Indoor Hotspot Scenario at 28 GHz

Millimeter Wave Channel Measurements and Modelling in an Ind...

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IEEE Conference on Vehicular technology (VTC)

作者： Pan Tang Jianhua Zhang Mansoor Shafi Pawel A. Dmochowski Peter J. Smith State Key Lab of Networking and Switching Technology Beijing University of Posts and Telecommunications Spark New Zealand Wellington New Zealand School of Engineering and Computer Science Victoria University of Wellington Wellington New Zealand School of Mathematics and Statistics Victoria University of Wellington Wellington New Zealand

ISBN: (纸本)9781538663592;9781538663585

Millimeter-wave channel models are fundamental for evaluating the performance of technologies for 5G. In this paper, we present two kinds of millimeter-wave channel measurements, fixed point measurements and virtual measurements, in an indoor open office. A correlation sounder with a bandwidth of 600 MHz is used to carry out these measurements. Then, channel parameters, e.g., the path loss, shadow fading, root mean square (RMS) delay spread (DS), K-factor, delay-cluster number and angular spread, are extracted and modelled. These extracted models will enable the generation of an impulse response for the indoor hotspot environment. Differences between our measurement-based channel model parameters and the International Telecommunication Union (ITU) channel model are discussed. The impact of differences on capacity are investigated by simulations. We find that the ITU channel model is optimistic about capacity. These results can help researchers to use millimeter-wave channel models for indoor office scenarios when evaluating 5G performance.

关键词： Antenna measurements Loss measurement Channel models Delays Millimeter wave measurements ITU 3GPP

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Estimate Air Quality Based on Mobile Crowd Sensing and Big Data

Estimate Air Quality Based on Mobile Crowd Sensing and Big D...

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IEEE International Symposium on World of Wireless Mobile and Multimedia Networks (WoWMoM)

作者： Cheng Feng Wendong Wang Ye Tian Xirong Que Xiangyang Gong State Key Lab of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781538627242

PM2.5 (particulate matter in the atmosphere with a diameter no more than 2.5 microns) in the air can cause great damage to human beings. It's a great challenge to offer a fine-grained and accurate PM2.5 monitoring service in urban areas as the required facilities are very expensive and huge. Since the PM2.5 has a significant scattering effect on visible light, the large-scale user-contributed image data collected by the mobile crowd sensing bring a new opportunity for understanding the urban PM2.5. After the analysis of image data, we find that several image features are very discriminative in PM2.5 inference. In this paper, we propose a fine-grained PM2.5 estimation method based on the random forest model without any PM2.5 measurement devices. We evaluate our approach with experiments based on five data sources: the meteorological data, the traffic data, the records from the monitoring sites, the POIs and the photos collected. The experimental results show that we have a high evaluation accuracy on PM2.5 estimation (precision: 0.875, recall: 0.872), which outperforms existing methods (Logistic, Naive Bayes, Random Tree, and BP ANN).

关键词： Monitoring Atmospheric modeling Air pollution Urban areas Feature extraction Real-time systems

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A Semi-Supervised Topic Model Incorporating Sentiment and Dynamic Characteristic

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China Communications 2016年第12期13卷 162-175页

作者： Lanshan Zhang Xi Ding Ye Tian Xiangyang Gong Wendong Wang Beijing Key Laboratory of Network System and Network Culture Beijing University of Posts and Telecommunications State Key Lab of Networking and Switching Technology Beijing University of Posts and Telecommunications

With the rapid popularization of social applications, various kinds of social media have developed into an important platform for publishing information and expressing opinion. Detecting hidden topics from the huge amount of user-generated contents is of great commerce value and social significance. However traditional text analysis approachesonly focus on the statistical correlation between words, but ignore the sentiment tendency and the temporal properties which may have great effects on topic detection results. This paper proposed a Dynamic Sentiment-Topic(DST) model which can not only detect and track the dynamic topics but also analyze the shift of public's sentiment tendency towards certain ***-Maximization algorithm was used in DST model to estimate the latent distribution, and we used Gibbs sampling method to sample new document set and update the hyper parameters and *** are conducted on a real dataset and the results show that DST model outperforms the existing algorithms in terms of topic detection and sentiment accuracy.

关键词： dynamic sentiment-topic model sentiment analysis topic detection

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