检索结果-南通市图书馆

Convolutional Neural Networks Based Indoor Wi-Fi Localization with a no.el Kind of CSI Images

在线全文

学校读者我要写书评

暂无评论

china Communications 2019年第9期16卷 250-260页

作者： Haihan Li Xiangsheng Zeng Yunzhou Li Shidong Zhou Jing Wang Beijing national research Center for Information Science and Techno.ogy Tsinghua UniversityBeijing 100084China Department of Electronic Engineering Tsinghua UniversityBeijing 100084China

Indoor Wi-Fi localization of mobile devices plays a more and more important role along with the rapid growth of location-based services and Wi-Fi mobile devices.In this paper,a new method of constructing the channel state information(CSI)image is proposed to improve the localization accuracy.Compared with previous methods of constructing the CSI image,the new kind of CSI image proposed is able to contain more channel information such as the angle of arrival(AoA),the time of arrival(TOA)and the amplitude.We construct three gray images by using phase differences of different antennas and amplitudes of different subcarriers of one antenna,and then merge them to form one RGB image.The localization method has off-line stage and on-line stage.In the off-line stage,the composed three-channel RGB images at training locations are used to train a convolutional neural network(CNN)which has been proved to be efficient in image recognition.In the on-line stage,images at test locations are fed to the well-trained CNN model and the localization result is the weighted mean value with highest output values.The performance of the proposed method is verified with extensive experiments in the representative indoor environment.

关键词： convolutional neural network indoor Wi-Fi localization channel state information CSI image

IEEE 802.11aj(45GHz):A New Very High Throughput Millimeter-Wave WLAN System

在线全文

学校读者我要写书评

暂无评论

china Communications 2014年第6期11卷 51-62页

作者： WANG Haiming HONG Wei CHEN Jixin SUN Bo PENG Xiaoming State Key Laboratory of Millimeter Waves Southeast University Strategy Planning Development ZTE Cooperation Institute for Infocommresearch(I2R)

This paper presents an overview of a new very high throughput millimeterwave WLAN system operating at 45 GHz band. We begin by reviewing standards process of IEEE 802.11aj(45GHz). Then the frequency spectrum allocation at 45 GHz band is introduced. Next, the channel measurement and mod-eling is given. Specifically, the millimeter-wave MIMO for physical layer enhancement is given in detail.

关键词： WLAN系统 IEEE 毫米波吞吐量标准工艺频谱分配信道测量 MIMO

A New TDD Scheme and Interference-Aware Precoding for Device-to-Device underlay Massive MIMO

在线全文

学校读者我要写书评

暂无评论

china Communications 2016年第S2期13卷 100-108页

作者： Xinxin Liu Xueru Li Yunzhou Li Ming Zhao Jing Wang State Key Laboratory on Microwave and Digital Communications Tsinghua National Laboratory for Information Science and Technology Tsinghua University Department of Electronic Engineering Tsinghua University

In device-to-device(D2D)underlay cellular networks with downlink spectrum sharing,massive MIMO seems promising as the large number of antennas at the base station(BS) can be utilized to suppress interference.However,the channel state information(CSI) from the BS to D2D receivers is required to obtain this advantage.In this paper,we first propose a no.el time division duplex(TDD) scheme for D2D users to acquire this CSI,without additional pilot overhead.Moreover,we propose an interference-aware MMSE precoder utilizing the acquired CSI from the BS to no. only cellular users but also D2D users to suppress the cellular-to-D2D interference.Simulation results show that our proposed TDD scheme and precoder can significantly improve the achievable sum spectral efficiency(SE) and D2D SE,compared to the classical MMSE precoder.Compared with the interferenceaware ZF precoder,whose performance severely degrades for large user numbers,our proposed interference-aware MMSE precoder can always guarantees a high and stable performance in terms of achievable SE.

关键词： device-to-device massive MIMO TDD scheme precoding

A Tri-Port MIMO Antenna Designed for Micro/Pico Cell Applications with Self-Decoupled Structure

在线全文

学校读者我要写书评

暂无评论

china Communications 2014年第11期11卷 1-6页

作者： WANG Han LIU Longsheng ZHANG Zhijun State Key Laboratory of Information Science Department of Electronics Engineering Tsinghua University Beijing 100084 P. R. China

A tri-port MIMO antenna designed for Micro/Pico-Cell application is proposed.It is based on printed elements with X-shaped arms,which are oriented to 0°,120° and240° in the azimuth plane.The arms of these elements are connected,with which a selfdecoupled structure is formed.The mutual coupling between adjacent elements is below-15 dB.Meanwhile,it size is compact and bidirectional radiation patterns with around 4dBi Gain and 92° 3dB beam width is achieved,which can provide good pattern diversity and full azimuth coverage in real applications.

关键词：天线设计 MIMO 三端口应用细胞结构解耦微微蜂窝

Allocation of Network Error Correction Flow on Disjoint Paths

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Techno.ogy 2015年第2期20卷 182-187页

作者： Zhiqing Xiao Yunzhou Li Jing Wang the Department of Electronic Engineering Tsinghua University the research Institute of Information Techno.ogy Tsinghua University

The diversity provided by disjoint paths can increase the survivability of communication networks. This paper considers the allocation of network error correction flow on a network that consists of disjoint paths from the source no.e to the destination no.e. Specifically, we propose an algorithm of allocating the path-flows to support the given rate with minimum cost. Our analysis shows that the asymptotic time complexity of this algorithm is linearithmic, and this algorithm is optimal in general

关键词： network survivability disjoint paths maximum distance separable codes network error correction

Real-Time Upstream Services Demonstration in Orthogonal Frequency Division Multiplexing- Passive Optical Network System

在线全文

学校读者我要写书评

暂无评论

china Communications 2014年第1期11卷 26-33页

作者： LI Ming Andrey Lukyanenko Sasu Tarkoma Antti Yl-Jski Department of Computer Science and Engineering Aalto University Department of Computer Science University of Helsinki

In recent years,dual-homed topologies have appeared in data centers in order to offer higher aggregate bandwidth by using multiple paths simultaneously.Multipath TCP(MPTCP) has been proposed as a replacement for TCP in those topologies as it can efficiently offer improved throughput and better fairness.However,we have found that MPTCP has a problem in terms of incast collapse where the receiver suffers a drastic goodput drop when it simultaneously requests data over multiple servers.In this paper,we investigate why the goodput collapses even if MPTCP is able to actively relieve hot spots.In order to address the problem,we propose an equally-weighted congestion control algorithm for MPTCP,namely EW-MPTCP,without need for centralized control,additional infrastructure and a hardware upgrade.In our scheme,in addition to the coupled congestion control performed on each subflow of an MPTCP connection,we allow each subflow to perform an additional congestion control operation by weighting the congestion window in reverse proportion to the number of servers.The goal is to mitigate incast collapse by allowing multiple MPTCP subflows to compete fairly with a single-TCP flow at the shared bottleneck.The simulation results show that our solution mitigates the incast problem and no.iceably improves goodput in data centers.

关键词：正交频分复用无源光网络服务网络系统实时现场可编程门阵列示范上游

Light dark sector searches at low-energy high-lumino.ity e^＋e^- colliders

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2016年第5期11卷 9-22页

作者： Peng-Fei Yin Shou-Hua Zhu Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Institute of Theoretical Physics & State Key Laboratory of Nuclear Physics and Techno.ogy Peking University Beijing 100871 China Collaborative Inno.ation Center of Quantum Matter Beijing 100871 China Center for High Energy Physics Peking University Beijing 100871 China

Although the standard model （SM） is extremely successful, there are various motivations for considering the physics beyond the SM. For example, the SM includes neither dark energy no. dark matter, which has been confirmed through astrophysical observations. Examination of the dark sector, which contains new, light, weakly-coupled particles at the GeV scale or lower, is well motivated by both theory and dark-matter detection experiments. In this mini-review, we focus on one particular case in which these new particles can interact with SM particles through a kinematic mixing term be- tween U（1） gauge bosons. The magnitude of the mixing can be parameterized by a parameter e. Following a brief overview of the relevant motivations and the constraints determined from numerous experiments, we focus on the light dark sector pheno.eno.ogy at low-energy high-lumino.ity e^＋e^- colliders. These colliders are ideal for probing the new light particles, because of their large production rates and capacity for precise resonance reconstruction. Depending on the details of a given model, the typical observed signatures may also contain multi lepton pairs, displaced vertices, and/or missing energy. Through the use of extremely large data samples from existing experiments, such as KLOE, CLEO, BABAR, Belle, and BESIII, the ε 〈 10^-4-10^-3 constraint can be obtained. Obviously, future experiments with larger datasets will provide opportunities for the discovery of new particles in the dark sector, or for stricter upper limits on ε. Once the light dark sector is confirmed, the particle physics landscape will be changed significantly.

关键词： dark photon electron-positron collider dark matter

LBMA： A no.el Locator Based Mobility Support Approach in Named Data Networking

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

china Communications 2014年第4期11卷 111-120页

作者： RAO Ying LUO Hongbin GAO Deyun ZHOU Huachun ZHANG Hongke School of Electronic and Information Engineering Beijing Jiaotong University Beijing 100044 P. R. China

To enhance seamless source mobility support in the mobile NDN(Named Data Networking) environment,we propose a no.el Locator Based Mobility support Approach,dubbed LBMA.In this approach,we assign a unique topologically layered locator to each AR(Access Route)in NDN network,and extend the AR with additional functionalities,such as caching and forwarding Interest packets on behalf of the source.Meanwhile,we add an optional field to the original NDN packet,and modify the Outgoing Interface(s) field in the AR's original FIB(Forwarding Information Base)entries,to record the mobility status and the current locator of the source.Specifically,the consumer in LBMA can continue the interrupted communication,without delivering Interest packets towards the old location of the source,no. waiting for all relevant devices completing the FIB entries updating.The performance analysis result indicates that LBMA has lower handoff cost and shorter handoff latency,compared with other existing source mobility support approaches.

关键词：数据网络定位基市场金银伦敦流动转发信息库移动性

Mechanism of the Rpn13-induced activation of Uch37

在线全文

学校读者我要写书评

暂无评论

Protein & Cell 2014年第8期5卷 616-630页

作者： Lianying Jiao Songying Ouyang Neil Shaw Gaojie Song Yingang Feng Fengfeng Niu Weicheng Qiu Hongtao Zhu Li-Wei Hung Xiaobing Zuo V. Eleono.a Shtykova Ping Zhu Yu-Hui Dong Ruxiang Xu Zhi-Jie Liu national Laboratory of Biomacromolecules Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China iHuman Institute ShanghaiTech University Shanghai 201210 China Shandong Provincial Key Laboratory ofEnergy-Genetics Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of Sciences Qingdao 266101 China Physics Division 'Los Alamos National Laboratory Los Alamos NM 87545 USA X-ray Science Division Argonne National Laboratory 9700 South Cass Avenue Argonne IL 60439 USA Institute of Crystallography~ Russian Academy of Sciences 59 Leninsky Pr. 117333 Moscow Russian Federation Center for Multi-disciplinary research Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049China Department of Nerosurgery The Military General Hospital of Beijing PLA Beijing 100700 China

Uch37 is a de-ubiquitinating enzyme that is activated by Rpn13 and involved in the proteasomal degradation of proteins. The full-length Uch37 was shown to exhibit low iso-peptidase activity and is thought to be auto-inhibited. Structural comparisons revealed that within a homo- dimer of Uch37, each of the catalytic domains was blocking the other＇s ubiquitin （Ub）-binding site. This blockage likely prevented Ub from entering the active site of Uch37 and might form the basis of auto-inhibition. To understand the mode of auto-inhibition clearly and shed light on the activation mechanism of Uch37 by Rpn13, we investigated the Uch37-Rpn13 complex using a combi- nation of mutagenesis, biochemical, NMR, and small- angle X-ray scattering （SAXS） techniques. Our results also proved that Uch37 oligomerized in solution and had very low activity against the fluorogenic substrate ubi- quitin-7-amino.4-methylcoumarin （Ub-AMC） of de-ubiq- uitinating enzymes. Uch37AHb＇Hc＇KEKE, a truncation removal of the C-terminal extension region （residues 256- 329） converted oligomeric Uch37 into a mono.eric form that exhibited iso-peptidase activity comparable to that of a truncation-containing the Uch37 catalytic domain only. We also demonstrated that Rpn13C （Rpn13 residues 270- 407） could disrupt the oligomerization of Uch37 by sequestering Uch37 and forming a Uch37-Rpn13 com- plex. Uch37 was activated in such a complex, exhibiting 12-fold-higher activity than Uch37 alone. Time-resolved SAXS （TR-SAXS） and FRET experiments supported the proposed mode of auto-inhibition and the activation mechanism of Uch37 by Rpn13. Rpn13 activated Uch37 by forming a 1：1 stoichiometric complex in which the active site of Uch37 was accessible to Ub.

关键词： Uch37-Rpn13 complex de-ubiquitination,SAXS analysis oligomerization iso-peptidase