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| 1 | Towards 6G wireless communication networks:vision,enabling technologies,and new paradigm shifts显示文摘The fifth generation(5G)wireless communication networks are being deployed worldwide from 2020 and more capabilities are in the process of being standardized,such as mass connectivity,ultra-reliability,and guaranteed low latency.However,5G will not meet all requirements of the future in 2030 and beyond,and sixth generation(6G)wireless communication networks are expected to provide global coverage,enhanced spectral/energy/cost efficiency,better intelligence level and security,etc.To meet these requirements,6G networks will rely on new enabling technologies,i.e.,air interface and transmission technologies and novel network architecture,such as waveform design,multiple access,channel coding schemes,multi-antenna technologies,network slicing,cell-free architecture,and cloud/fog/edge computing.Our vision on 6G is that it will have four new paradigm shifts.First,to satisfy the requirement of global coverage,6G will not be limited to terrestrial communication networks,which will need to be complemented with non-terrestrial networks such as satellite and unmanned aerial vehicle(UAV)communication networks,thus achieving a space-airground-sea integrated communication network.Second,all spectra will be fully explored to further increase data rates and connection density,including the sub-6GHz,millimeter wave(mmWave),terahertz(THz),and optical frequency bands.Third,facing the big datasets generated by the use of extremely heterogeneous networks,diverse communication scenarios,large numbers of antennas,wide bandwidths,and new service requirements,6G networks will enable a new range of smart applications with the aid of artificial intelligence(AI)and big data technologies.Fourth,network security will have to be strengthened when developing 6G networks.This article provides a comprehensive survey of recent advances and future trends in these four aspects.Clearly,6G with additional technical requirements beyond those of 5G will enable faster and further communications to the extent that the boundary between physical and cyber worlds disappears. | Xiaohu YOU Cheng-Xiang WANG Jie HUANG Xiqi GAO Zaichen ZHANG Mao WANG Yongming HUANG Chuan ZHANG Yanxiang JIANG Jiaheng WANG Min ZHU Bin SHENG Dongming WANG Zhiwen PAN Pengcheng ZHU Yang YANG Zening LIU Ping ZHANG Xiaofeng TAO Shaoqian LI Zhi CHEN Xinying MA Chih-Lin I Shuangfeng HAN Ke LI Chengkang PAN Zhimin ZHENG Lajos HANZO Xuemin(Sherman)SHEN Yingjie Jay GUO Zhiguo DING Harald HAAS Wen TONG Peiying ZHU Ganghua YANG Jun WANG Erik GLARSSON Hien Quoc NGO Wei HONG Haiming WANG Debin HOU Jixin CHEN Zhe CHEN Zhangcheng HAO Geoffrey Ye LI Rahim TAFAZOLLI Yue GAO HVincent POOR Gerhard P.FETTWEIS Ying-Chang LIANG | 2021 | Science China(Information Sciences)2021，64，1： | 122 |
| 2 | Therapeutic effect of electroacupuncture,massage,and blocking therapy on external humeral epicondylitis显示文摘OBJECTIVE:To compare two therapeutic methods:electroacupuncture + massage + blocking therapy,and blocking therapy alone in the treatment of external humeral epicondylitis.METHODS:Eighty-six patients were randomized into two groups with 43 in each. The treatment group received electroacupuncture + massage +blocking therapy, while the control group received blocking therapy only. A course of electroacupuncture treatment included therapy once a day for 10days. There were 10 treatments in a massage course and massage was given once a day, with a1-week interval given before the next course. A course of blocking treatment included therapy once a week, for twototaltreatments,andgenerallyno more than three times. The therapeutic effects were evaluated with the visual analog scale(VAS),grip strength index(GSI) score, and Mayo elbow performance score(MEPS) before treatment and at0, 6, 12, and 24 months after treatment to observe thetotaleffectiverate.RESULTS: In the treatment and control groups before treatment and at 0, 6, 12, and 24 months after treatment, the VAS scores were: 6.5±1.9 and 6.4±1.6; 4.6±1.3 and 4.6±1.7; 4.8±1.3 and 4.8±1.2; 4.6±1.2 and 6.6±1.6; and 6.5±1.6 and 6.5±1.3, respectively. The GSI scores were 63±8 and 63±8; 84±6and82±7;82±7and82±6;84±6and62±8;and64±6 and 64±7, respectively.The MEPS of both groups were65±7and66±8;85±6and84±7;84±5and84±7;80±7and66±6;and65±6and65±7,respectively.The total effective rates of the treatment and control groups at 0, 6, 12, and 24 months after treatment were 87.5% and 85.0%; 85.0% and 82.5%;80.0% and 12.5%; and 2.5% and 5.0%, respectively.Compared with the treatment group, the control group had greater joint function, better the rapeutic effect, and lower pain intensity(P<0.01), indicating a high recurrence rate in the 12th month after treatment.There were no differences inVAS, GSI, or MEPS at 0, 6, and 24 months after treatment(P>0.05)betweenthetwogroups.CONCLUSION: We found that both methods were effective for external humeral epicondylitis. After 6months of treatment,the effects were good in both groups. However, in the 12th month, the control group had a relatively severe relapse. After 24months, both groups relapsed. The effect of electroacupuncture, massage, and blocking therapy used in combination lasted longer, delaying the recurrence of the disease. | Xinjian Li Kun Zhou Enming Zhang Zhen xiQi Weiqing Sun Liangfu Xu Jianfeng Xu Youzhi Cai Ronghui Wang | 2014 | Journal of Traditional Chinese Medicine2014，34，3： | 6 |
| 3 | Robust MMSE precoding for massive MIMO transmission with hardware mismatch显示文摘Due to hardware mismatch, the channel reciprocity of time-division duplex massive multipleinput multiple-output system is impaired. Under this condition, there exist several different approaches for base station(BS) to obtain downlink(DL) channel information based on the minimum mean-square-error(MMSE) estimation method. In this paper, we show that with the hardware mismatch parameters BS can obtain the same DL channel information via these different approaches. As the obtained DL channel information is usually imperfect, we propose a precoding technique based on the criterion that minimizes the mean-square-error(MSE) of signal detection at the user terminals(UTs). The proposed precoding is robust to the channel estimation error and significantly improves the system performance compared to the conventional regularized zero-forcing precoding. Furthermore, we derive an asymptotic approximation of the ergodic sum rate for the proposed precoding using the large dimensional random matrix theory, which is tight as the number of antennas both at the BS and UT approach infinity with a fixed non-zero and finite ratio. This approximation can provide a reliable sum rate prediction at a much lower computation cost than Monte Carlo simulations. Simulation results show that the approximation is accurate even for a realistic system dimension. | Yan CHEN Xiqi GAO Xiang-Gen XIA Li YOU | 2018 | Science China(Information Sciences)2018，61，4： | 3 |
| 4 | Fast-convolution multicarrier based frequency division multiple access显示文摘Fast-convolution multicarrier(FCMC), the asynchronous waveform with ultra-low sidelobe, has appeared to be a promising waveform technique for future wireless communications. In this paper, we investigate the filter bank optimization as well as receiver design including low-complexity channel estimator and equalizer for FCMC based frequency division multiple access(FDMA). Starting from the conventional multi-carrier signals, we first derive a vectorized signal model as a framework to systematically design the FCMC transceiver. For nearly perfect reconstruction(NPR) filter banks design, an optimization criterion which consists of minimizing received signal segments’ mean square error(MSE) is proposed. From the fact that Toeplitz matrices can be asymptotically diagonalized by discrete Fourier transform(DFT) matrix, the channel equalizer can be simplified to one-tap frequency domain equalizer when DFT size is large enough.The minimum mean square error(MMSE) criterion is then applied to calculate the coefficients of onetap frequency domain equalizer. In practice, due to the channel fading, the channel estimation has to be performed to obtain the channel state information(CSI) which is required by the channel equalization. To this end, we propose a combined cyclic prefix(CP) and cyclic suffix(CS) pilot structure which facilitates to estimate the frequency domain CSI directly in the receiver end. The proposed FCMC based FDMA features low-complexity receiver, adjustable users’ bandwidth and low peak-to-average power ratio. Simulation results confirm the performance of the proposed scheme. | Yining LI Wenjin WANG Jiaheng WANG Xiqi GAO | 2019 | Science China(Information Sciences)2019，62，8： | 2 |
| 5 | User scheduling for downlink FD-MIMO systems under Rician fading exploiting statistical CSI显示文摘In this paper, we consider the user scheduling algorithm for downlink full-dimension multipleinput multiple-output(FD-MIMO) system under Rician fading channels. We assume that two-dimensional(2 D) large-scale antenna array is deployed at base station(BS). An approximation of user's signal-tointerference-plus-noise ratio(SINR) and a lower bound of user's average signal-to-leakage-plus-noise ratio(SLNR) are derived. Based on these, two user scheduling algorithms exploiting only statistical channel state information(CSI) are proposed. The proposed algorithms take both the achievable sum rate and fairness into account. Simulation results reveal that the proposed user scheduling algorithms can make good trade-off between the achievable rate and fairness. | Xiao LI Tingting SUN Nana QIN Shi JIN Xiqi GAO | 2018 | Science China(Information Sciences)2018，61，8： | 2 |
| 6 | Near-optimal pow-er allocation for MIMO channels with mean or covar-iance feedback 显示文摘 | Li Xiao Jin Shi Gao Xiqi | 2010 | IEEE Transactions on Communi-cations2010，58，1： | 1 |
| 7 | Taraxasterol ameliorates dextran sodium sulfate-induced murine colitis via improving intestinal barrier and modulating gut microbiota dysbiosis显示文摘Taraxasterol(TAX)has been proven to prevent and treat inflammatory diseases.However,the effects of TAX on intestinal barrier and the diversity,structure,and function of gut microbiota have yet to be elucidated in dextran sodium sulfate(DSS)-induced colitis mice.Our objectives are to evaluate the effect of TAX on intestinal barrier and its impact on gut microbiota.Herein,immunofluorescence analysis is conducted to determine the expressions of tight junction(ZO-1)and mucin(Mucin-2)proteins.The abundance,diversity,and function of fecal colonies are investigated by using 16S rDNA sequencing,and the influence of TAX on the gut microbiota in mice is also analyzed.Our results suggest that TAX attenuates the symptoms in DSS-induced colitis mice by reducing the DAI score,increasing colon length,alleviating histopathological damage of colon tissues,and improving intestinal barrier.16S rDNA sequencing of fecal samples indicates that TAX intervention has a regulatory effect on DSS-induced gut microbiota dysbiosis at different taxonomic levels.TAX increases microbial diversity that is reduced by DSS.It normalizes the relative abundance of Bacteroidetes and the ratio of Bacteroidetes/Firmicutes.In addition,treatment with TAX has a better effect on the function of metabolisms,such as nucleotide,lipid,and bile acid metabolism.These findings suggest that TAX may be a good candidate for the remission of colitis,which is related to improving intestinal barrier and modulating gut microbiota. | Chen Li Meng Wang Xiqi Chen Wei Chen | 2022 | Acta Biochimica et Biophysica Sinica2022，54，3： | 1 |
| 8 | Multi-user MIMO downlink eigen-mode transmission over jointly correlated MIMO channels显示文摘The study of multi-user multiple-input multiple-output (MU-MIMO) systems has emerged recently as an important research topic because such systems have the potential to combine the high capacity that can be achieved through MIMO processing with the benefits of spatial-division multiple-access.However,receiver and transmitter channel state information (CSI) is generally required,especially for the downlink channel.In this paper,MU-MIMO downlink transmission systems with statistical CSI at the transmitter are studied for jointly correlated MIMO channels.Eigen-mode space division multiple access transmission is derived based on the maximization of the ergodic sum rate,and two eigen-mode power allocation algorithms are proposed using matrix permanent and convex optimization theory.The new algorithms can overcome the limitations of the existing multi-user downlink transmission algorithm in practical applications. | LI Xiao JIN Shi GAO XiQi | 2011 | Science China(Information Sciences)2011，54，10： | 1 |
| 9 | TIME-DOMAIN INTERPOLATION ON GRAPHICS PROCESSING UNIT显示文摘The signal processing speed of spectral domain optical coherence tomography(SD-OCT)has become a bottleneck in a lot of medical applications.Recently,a time-domain interpolation method was proposed.This method can get better signal-to-noise ratio(SNR)but much-reduced signal processing time in SD-OCT data processing as compared with the commonly used zeropadding interpolation method.Additionally,the resampled data can be obtained by a few data and coefficients in the cutoff window.Thus,a lot of interpolations can be performed simultaneously.So,this interpolation method is suitable for parallel computing.By using graphics processing unit(GPU)and the compute unified device architecture(CUDA)program model,time-domain interpolation can be accelerated significantly.The computing capability can be achieved more than 250,000 A-lines,200,000 A-lines,and 160,000 A-lines in a second for 2,048 pixel OCT when the cutoff length is L=11,L=21,and L=31,respectively.A frame SD-OCT data(400A-lines×2,048 pixel per line)is acquired and processed on GPU in real time.The results show that signal processing time of SD-OCT can befinished in 6.223 ms when the cutoff length L=21,which is much faster than that on central processing unit(CPU).Real-time signal processing of acquired data can be realized. | XIQI LI GUOHUA SHI YUDONG ZHANG | 2011 | Journal of Innovative Optical Health Sciences2011，4，1： | 1 |
| 10 | Impedance spectroscopy analysis of doped PbWO4 single crystals 显示文摘 | HUANG Hongwei LI Wensheng FENG Xiqi | 2001 | Phys Status Solidi (a)2001，187，： | 1 |
| 11 | Robust online energy efficiency optimization for distributed multi-cell massive MIMO networks显示文摘This paper studies the energy efficiency(EE)oriented precoding design in multi-cell massive multiple-input multiple-output(MIMO)systems,with only statistical channel state information(CSI)at the transmitter.During the transmission,as the channel varies dynamically with time and the previously obtained CSI becomes outdated,the base stations must adjust their transmit policies accordingly.To tackle this issue,we propose an online EE maximization algorithm that can achieve a no-regret transmission;i.e.,the performance of this online method gradually approaches that of the fixed offline method which has full knowledge of the future CSI.Specifically,we first construct the online EE optimization problem in a distributed way to reduce the information required to be exchanged between cells.Then,we apply the largedimensional random matrix theory to lower the calculation complexity,and the Charnes-Cooper transform to address the nonconvexity of the problem,respectively.The online gradient ascent method is utilized to perform this no-regret power allocation strategy based on all past CSI.We also assess the robustness of the algorithm to estimation error of statistical CSI under some mild conditions which can usually be satisfied in practice.Numerical results demonstrate the no-regret property and the robustness of the proposed online algorithm for energy efficient multi-cell massive MIMO transmission. | Li YOU Yufei HUANG Wen ZHONG Wenjin WANG Xiqi GAO | 2023 | Science China(Information Sciences)2023，66，3： | 1 |
| 12 | Carbon source recovery from waste sludge reduces greenhouse gas emissions in a pilot-scale industrial wastewater treatment plant显示文摘Carbon cycle regulation and greenhouse gas(GHG)emission abatement within wastewater treatment plants(WWTPs)can theoretically improve sustainability.Currently,however,large amounts of external carbon sources used for deep nitrogen removal and waste sludge disposal aggravate the carbon footprint of most WWTPs.In this pilot-scale study,considerable carbon was preliminarily recovered from primary sludge(PS)through short-term(five days)acidogenic fermentation and subsequently utilized on-site for denitrification in a wool processing industrialWWTP.The recovered sludge-derived carbon sources were excellent electron donors that could be used as additional carbon supplements for commercial glucose to enhance denitrification.Additionally,improvements in carbon and nitrogen flow further contributed to GHG emission abatement.Overall,a 9.1%reduction in sludge volatile solids was achieved from carbon recovery,which offset 57.4%of external carbon sources,and the indirect GHG emissions of the target industrial WWTP were reduced by 8.05%.This study demonstrates that optimizing the allocation of carbon mass flow within a WWTP has numerous benefits. | Qiandi Wang Xiqi Li Wenzong Liu Siyuan Zhai Qiongying Xu Chang'an Huan Shichen Nie Qinghua Ouyang Hongcheng Wang Aijie Wang | 2023 | Environmental Science and Ecotechnology2023，，2： | 1 |
| 13 | Multi-cell massive MIMO transmission with coordinated pilot reuse显示文摘In this paper, we propose a coordinated pilot reuse(CPR) approach to reduce the pilot overhead for multi-cell massive multi-input multi-output transmission. Unlike the conventional multi-cell pilot reuse approach in which pilots can only be reused among different cells, the proposed CPR approach allows pilots to be reused among both inter-cell and intra-cell user equipments, and thus, pilot overhead can be efficiently reduced. For spatially correlated Rayleigh fading channels, we first present a CPR-based channel estimation method and a low complexity pilot allocation algorithm. Because CPR might lead to additional pilot interference, we develop a statistically robust uplink receiver and downlink precoder that takes channel estimation errors into account. The proposed uplink receiver and downlink precoder are robust to channel state information inaccuracy, and thus, can guarantee a certain transmission performance. Monte-Carlo simulations illustrate the significant performance improvement in net spectral efficiency offered by the proposed CPR approach. | ZHONG Wen YOU Li LIAN TengTeng GAO XiQi | 2015 | Science China(Technological Sciences)2015，58，12： | 1 |
| 14 | LoS MIMO Transmission for LEO Satellite Communication Systems显示文摘To provide global service with low latency, the broadband low earth orbits (LEO) satellite constellation based communication systems have become one of the focuses in academic and industry. To allow for wideband access for user links, the feeder link of LEO satellite is correspondingly required to support high throughput data communications. To this end, we propose to apply line-of-sight (LoS) multiple-input multiple-output (MIMO) transmission for the feeder link to achieve spatial multiplexing by optimizing the antenna arrangement. Unlike the LoS MIMO applications for static scenarios, the movement of LEO satellites make it impractical to adjust the optimal antenna separation for all possible satellite positions. To address this issue, we propose to design the antenna placement to maximize the ergodic channel capacity during the visible region of the ground station. We first derive the closed-form probability distribution of the satellite trajectory in visible region. Based on which the ergodic channel capacity can be then calculated numerically. The antenna placement can be further optimized to maximize the ergodic channel capacity. Numerical results verify the derived probability distribution of the satellite trajectory, and show that the proposed LoS MIMO scheme can significantly increase the ergodic channel capacity compared with the existing SISO one. | Lingxuan Li Tingting Chen Wenjin Wang Xiaohang Song Li You Xiqi Gao | 2022 | China Communications2022，19，10： | 1 |
| 15 | 4350<ce:hsp sp='0.25'/>W quasi-continuous-wave operation of a diode face-pumped ceramic Nd: YAG slab laser显示文摘 | Junchi Chen Jiang Li Jialin Xu Wenbin Liu Yong Bo Xiqi Feng Yiting Xu Dongliang Jiang Zhongzheng Chen Yubai Pan Yading Guo Biao Yan Chang Guo Lei Yuan Hongtao Yuan Yanyong Lin Yunsheng Xiao Qinjun Peng Wenqiang Lei Dafu Cui Zuyan Xu | 2014 | Optics and Laser Technology2014，，： | 1 |
| 16 | Non-Ischemic, Non-Hypoxic Myocardial Injury, and Long-Term Mortality in Patients with Coronavirus Disease 2019: A Retrospective Cohort Study显示文摘Objective:Cardiac damage is commonly reported in patients with coronavirus disease 2019(COVID-19)but its prevalence and impact on the long-term survival of patients remain uncertain.This study aimed to explore the prevalence of myocardial injury and assess its prognostic value in patients with COVID-19.Methods:A single-center,retrospective cohort study was performed at the Affiliated Hospital of Jianghan University.Data from 766 patients with confirmed COVID-19 who were hospitalized from December 27,2019 to April 25,2020 were collected.Demographic,clinical,laboratory,electrocardiogram,treatment data and all-cause mortality during follow-up were collected and analyzed.Results:Of the 766 patients with moderate to critically ill COVID-19,86(11.2%)died after a mean follow-up of 72.8 days.Myocardial injury occurred in 94(12.3%)patients.The mortality rate was 64.9%(61/94)and 3.7%(25/672)in patients with and without myocardial injury,respectively.Cox regression showed that myocardial injury was an independent risk factor for mortality(hazard ratio:8.76,95%confidence interval:4.76–16.11,P<0.001).Of the 90 patients with myocardial injury with electrocardiogram results,sinus tachycardia was present in 29,bundle branch block in 26,low voltage in 10,and abnormal T-wave in 53.Conclusions:COVID-19 not only involves pneumonia but also cardiac damage.Myocardial injury is a common complication and an independent risk factor for mortality in COVID-19 patients. | Fajiu Li Xijie Zhu Ziyang Zhu Yinjian Yang Zhuang Tian Duolao Wang Shi Chen Xiaoyan Gao Yalin Xu Bo Zhang Wei Yu Min Liu Xiqi Xu Chenghong Li Shuyang Zhang | 2022 | Cardiology Discovery2022，2，2： | 0 |
| 17 | Acceleration of optical coherence tomography signal processing by multi-graphics processing units显示文摘A multi-GPU system designed for high-speed,real-time signal processing of optical coherencetomography(OCT)is described herein.For the OCT data sampled in linear wave numbers,themaximum procesing rates reached 2.95 MHz for 1024-OCT and 1.96 MHz for 2048-OCT.Data sampled using linear wavelengths were re-sampled using a time-domain interpolation method and zero-padding interpolation method to improve image quality.The maximum processing rates for1024-OCT reached 2.16 MHz for the time-domain method and 1.26 MHz for the zero-paddingmethod.The maximum processing rates for 2048-0CT reached_1.58 MHz,and 0.68 MHz,respectively.This method is capable of high-speed,real-time processing for O CT systems. | Xiqi Li Guohua Shi Ping Huang Yudong Zhang | 2014 | Journal of Innovative Optical Health Sciences2014，7，3： | 0 |
| 18 | Dense 3D surface reconstruction of large-scale streetscape from vehicle-borne imagery and LiDAR显示文摘Accurate and efficient three-dimensional(3D)streetscape reconstruction is the fundamental ability for an exploration vehicle to navigate safely and perform high-level tasks.Recently,remarkable progress has been made in streetscape reconstruction with visual images and light detection and ranging(LiDAR),but they have difficulties either in scaling and reconstructing large-scale outdoors or in efficient processing.To address these issues,this paper proposed an automatic method for incremental dense reconstruction of large-scale 3D streetscapes from coarse to fine at near real time.Firstly,the pose of vehicle is estimated by visual and laser odometry(VLO)and the state-of-the-art pyramid stereo matching network(PSMNet)is introduced to estimate depth information.Then,incremental dense 3D streetscape reconstruction is conducted by key-frame selection and coarse registration with local optimization.Finally,redundant and noise points are removed through multiple filtering,resulting good quality of dense reconstruction.Comprehensive experiments were undertaken to check the visual effect,trajectory pose error and multi-scale model to model cloud comparison(M3C2)based on reference trajectories and reconstructions provided by the state-of-the-art method,showing the precision,recall and F-score of sampling core points(SCPs)are over 80.42%,71.68%and 77.19%,respectively,which verified the proposed method. | Xiaohu Lin Bisheng Yang Fuhong Wang Jianping Li Xiqi Wang | 2021 | International Journal of Digital Earth2021，14，5： | 0 |
| 19 | Improved wavelet hierarchical threshold filter method for optical coherence tomography image de-noising显示文摘According to the speckle feature in Optical coherence tomography(OCT),images with speckleindicate not only noise but also signals,an improved wavelet hierarchical threshold filter(IWHTF)method is proposed.At first,a modified hierarchical threshold-selected algorithm isused to prevent signals from being removed by asssing suitable thresholds for different noiselevels,Then,an improved wavelet threshold function based on two traditional threshold fumnc.tions is proposed to trade-ff betwen speckle removing and sharpness degradation.The de-noising results of an OCT finger skin image shows that the IWHTF method obtains betterobjective evaluation metrics and visual image quality improvement,Whenαa=0.2,β=5.0 andK=1.2,the improved method can achieve 9.58 dB improvement in signal-to-noise ratio,withsharpnesdegraded by 3.81%. | Jing Cao Pinghe Wang Bo Wu Guohua Shi Yan Zhang Xiqi Li Yudong Zhang Yong Liu | 2018 | Journal of Innovative Optical Health Sciences2018，，3： | 0 |
| 20 | Formation of High Concentration Cr^4+ Ion in a PbWO4 Single Crystal显示文摘 | Xiqi Feng Weifeng Li Tong B. Tang | 2006 | 量子光学学报2006，12，B08： | 0 |
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