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An improved wind quality control for the China-France Oceanography Satellite (CFOSAT) scatterometer

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Acta Oceanologica Sinica 2024年第5期43卷 100-109页

作者： xiaoheng Mou Wenming Lin School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing 210044China Key Laboratory of Space Ocean Remote Sensing and Application Ministry of Natural ResourcesBeijing 100081China

Quality control(QC)is an essential procedure in scatterometer wind retrieval,which is used to distinguish good-quality data from poor-quality wind vector cells(WVCs)for the sake of wind *** current wind processor of the China-France Oceanography Satellite(CFOSAT)scatterometer(CSCAT)adopts a maximum likelihood estimator(MLE)-based QC method to filter WVCs affected by geophysical noise,such as rainfall and wind *** the first Ku-band rotating fan-beam scatterometer,CSCAT can acquire up to 16 observations over a single WVC,giving abundant information with diverse incidence/azimuth angles,as such its MLE statistical characteristics may be different from the previous *** this study,several QC indicators,including MLE,its spatially averaged value(MLE_(m)),and the singularity exponents(SE),are analyzed using the collocated Global Precipitation Mission rainfall data as well as buoy data,to compare their sensitivity to rainfall and wind *** results show that wind error characteristics of CSCAT under different QC methods are similar to those of other Ku-band scatterometers,i.e.,SE is more suitable than other parameters for the wind QC at outer-swath and nadir regions,while MLE_(m) is the best QC indicator for the sweet region ***,SE is much more favorable than others at high wind *** combining different indicators,an improved QC method is developed for *** validation with the collocated buoy data shows that it accepts more WVCs,and in turn,improves the quality control of CSCAT wind data.

关键词： China-France Oceanography Satellite(CFOSAT) scatterometer winds quality control(QC) singularity exponent(SE)

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基于听觉感知特性的语音质量客观评价方法

西南交通大学学报 2013年第4期48卷 756-760页

作者：谭晓衡许可秦基伟重庆大学通信工程学院重庆400044

讨论了基于MFCC(Mel-frequency cepstral coefficients)特征参数的语音质量客观评价方法 Mel-CD(Mel-cepstral distance measure).根据心理声学原理将Johannesma提出的人耳听觉模型和非线性压缩变换引入MFCC特征参数的提取过程,用Gammatone滤波器组对人耳基底膜进行仿真.利用改进后的MFCC作为语音信号特征参数,提出了一种更加符合人耳听觉感知特性的客观评价方法——Mel-GD(Mel-cepstral gammatone filter bankdistance measure).性能测试结果表明:所提算法与Mel-CD算法在时间复杂度上保持一致,评价结果的主观与客观的相关度提高了4.9%,平均估计偏差改善了45.5%.

关键词：语音质量 MFCC Gammatone滤波器组非线性变换

Wireless Power Supply Based on MNG-MNZ Metamaterial for Cardiac Pacemakers

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 103-112页

作者： Weihua Chen Jingtao Jia xiaoheng Yan Yuhang Song Jiayi Li Faculty of Electrical and Control Engineering Liaoning Technical UniversityNo.188Longwan South StreetXingchengHuludao 125105China CES

To solve the low power transfer efficiency and magnetic field leakage problems of cardiac pacemaker wireless powering, we proposed a wireless power supply system suitable for implanted cardiac pacemaker based on mu-negative(MNG) and mu-nearzero(MNZ) metamaterials. First, a hybrid metamaterial consisted of central MNG unit for magnetic field concentration and surrounding MNZ units for magnetic leakage shielding was established by theoretical calculation. Afterwards, the magnetic field distribution of wireless power supply system with MNG-MNZ metamaterial slab was acquired via finite element simulation and verified to be better than the distribution with conventional MNG slab deployed. Finally, an experimental platform of wireless power supply system was established with which power transfer experiment and system temperature rise experiment were *** and experimental results showed that the power transfer efficiency was improved from 44.44%,19.42%, 8.63% and 6.19% to 55.77%, 62.39%, 20.81%and 14.52% at 9.6 mm, 20 mm, 30 mm and 50 mm,respectively. The maximum SAR acquired by SAR simulation under human body environment was-7.14 dbm and maximum reduction of the magnetic field strength around the receiving coil was 2.82 A/m. The maximum temperature rise during 30min charging test was 3.85℃,and the safety requirements of human bodies were met.

关键词： Cardiac pacemaker MNG metamaterial MNZ metamaterial Wireless power supply system

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认知无线电中频谱空洞统计特性分析与分配

西安电子科技大学学报 2017年第2期44卷 107-113页

作者：黄杰曾孝平简鑫谭晓衡张耀乐重庆大学通信工程学院重庆400000

针对动态网络场景的频谱空洞可用带宽存在时变性,传统基于静态特性的认知无线电资源分配方式难以直接应用的问题,推导了频谱空洞可用带宽概率密度函数通用表示形式,并联合随机多背包模型提出基于频谱空洞统计特性的离散频谱分配策略,实... 详细信息

针对动态网络场景的频谱空洞可用带宽存在时变性,传统基于静态特性的认知无线电资源分配方式难以直接应用的问题,推导了频谱空洞可用带宽概率密度函数通用表示形式,并联合随机多背包模型提出基于频谱空洞统计特性的离散频谱分配策略,实现了考虑频谱空洞可用带宽统计特性的资源分配.数值仿真表明,与传统算法相比,所提算法在频谱空洞变化频繁场景下,能有效减少频谱变化产生的冲突,具有较高的网络利用率.

关键词：认知无线电资源分配频谱空洞随机多背包

The role and applications of extracellular vesicles in osteoporosis

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Bone Research 2024年第1期12卷 62-77页

作者： Fei Fang Jie Yang Jiahe Wang Tiantian Li Erxiang Wang Demao Zhang xiaoheng Liu Chenchen Zhou Institute of Biomedical Engineering West China School of Basic Medical Sciences&Forensic MedicineSichuan UniversityChengdu 610041China State Key Laboratory of Oral Diseases National Clinical Research Center for Oral DiseasesWest China Hospital of StomatologySichuan UniversityChengdu 610041China

Osteoporosis is a widely observed condition characterized by the systemic deterioration of bone mass and microarchitecture,which increases patient susceptibility to fragile *** intricate mechanisms governing bone homeostasis are substantially impacted by extracellular vesicles(EVs),which play crucial roles in both pathological and physiological *** derived from various sources exert distinct effects on ***,EVs released by osteoblasts,endothelial cells,myocytes,and mesenchymal stem cells contribute to bone formation due to their unique cargo of proteins,miRNAs,and ***,EVs secreted by osteoclasts and immune cells promote bone resorption and inhibit bone ***,the use of EVs as therapeutic modalities or biomaterials for diagnosing and managing osteoporosis is ***,we review the current understanding of the impact of EVs on bone homeostasis,including the classification and biogenesis of EVs and the intricate regulatory mechanisms of EVs in ***,we present an overview of the latest research progress on diagnosing and treating osteoporosis by using ***,we discuss the challenges and prospects of translational research on the use of EVs in osteoporosis.

关键词： osteoporosis homeostasis biomaterials

改进的多信道S-ALOHA暂态性能分析办法及其应用

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电子与信息学报 2016年第8期38卷 1894-1900页

作者：简鑫曾孝平谭晓衡田蜜苗丽娟重庆大学通信工程学院重庆400030

海量机器类终端(或MTC终端)同步入网时,其业务呈现瞬时突发性,这使得基于齐次或复合泊松假设的多信道S-ALOHA稳态性能分析办法难以直接应用。该文以第i个随机接入时隙内第j次进行随机接入的用户数Mi(j)作为状态变量,提出了一种沿Mi(j)的... 详细信息

海量机器类终端(或MTC终端)同步入网时,其业务呈现瞬时突发性,这使得基于齐次或复合泊松假设的多信道S-ALOHA稳态性能分析办法难以直接应用。该文以第i个随机接入时隙内第j次进行随机接入的用户数Mi(j)作为状态变量,提出了一种沿Mi(j)的j方向迭代进行多信道S-ALOHA暂态性能分析的办法及其近似形式。该迭代办法可建立第i个随机接入时隙内第j次进行随机接入的用户数与第x个随机接入时隙内新到用户数的直接关系(其中x

关键词：物联网机器类通信突发性业务暂态性能分析

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基于高阶累积量和小波变换的调制识别算法

系统工程与电子技术 2018年第1期40卷 171-177页

作者：谭晓衡褚国星张雪静杨扬重庆大学生物感知与智能信息处理重庆市重点实验室重庆400044 重庆大学通信工程学院重庆400044 安徽四创电子股份有限公司安徽合肥230001

针对当前调制识别算法在低信噪比下识别率不高的问题,提出结合高阶累积量和小波变换的混合调制识别算法。该算法利用了小波变换提取的两个特征参数,以及基于四阶和六阶累积量构造出一个新的特征参数,并应用反向传播神经网络分类器对调... 详细信息

针对当前调制识别算法在低信噪比下识别率不高的问题,提出结合高阶累积量和小波变换的混合调制识别算法。该算法利用了小波变换提取的两个特征参数,以及基于四阶和六阶累积量构造出一个新的特征参数,并应用反向传播神经网络分类器对调制信号进行识别。仿真结果证明,该算法能够在信噪比低至2dB时,识别率仍可达到98%以上,由此证明了该方法的有效性和稳健性。

关键词：调制识别高阶累积量小波变换神经网络

带冲突检测的两阶段无连接接入协议最优资源分配

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通信学报 2019年第5期40卷 117-124页

作者：简鑫王芳宋健付澍谭晓衡曾孝平重庆大学微电子与通信工程学院重庆400044

无连接接入协议允许机器类终端不需要建立无线承载就进行小数据传输,以降低系统信令开销与终端能耗。两阶段无连接接入协议可通过合理分配调度请求阶段和数据传输阶段的资源提高系统吞吐量,特别适合中高负载场景。基于此,完成了一类称... 详细信息

无连接接入协议允许机器类终端不需要建立无线承载就进行小数据传输,以降低系统信令开销与终端能耗。两阶段无连接接入协议可通过合理分配调度请求阶段和数据传输阶段的资源提高系统吞吐量,特别适合中高负载场景。基于此,完成了一类称作带冲突检测的两阶段无连接接入协议的性能极限与最优资源分配策略的理论分析,并设计了一种不需要用户数估计的动态资源分配算法。数值分析验证了上述理论分析的正确性,表明了所提动态资源分配算法与已知每个接入周期内用户数的理想算法的性能差异可控制在4%以内。上述结果可为面向海量机器类通信的无线接入协议的优化设计提供参考。

关键词：大规模机器类通信无连接接入性能极限最优资源分配

多信道S-ALOHA功率攀升机制的性能分析

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西安电子科技大学学报 2019年第3期46卷 59-65页

作者：简鑫王芳宋健方伟蒋欣曾孝平谭晓衡重庆大学微电子与通信工程学院重庆400044 中国商用飞机有限责任公司北京民用飞机技术研究中心北京100000

针对海量机器类终端同步入网时因重传带来的功耗急剧增加问题,以第i个时隙内进行第j次随机接入的用户数作为状态变量,给出了带功率攀升机制的多信道S-ALOHA的暂态性能分析办法(尤其是功耗与时延模型)及其接入强度稳定时的近似形式。以3... 详细信息

针对海量机器类终端同步入网时因重传带来的功耗急剧增加问题,以第i个时隙内进行第j次随机接入的用户数作为状态变量,给出了带功率攀升机制的多信道S-ALOHA的暂态性能分析办法(尤其是功耗与时延模型)及其接入强度稳定时的近似形式。以3GPP机器类通信两种业务模型进行数值仿真,验证了所提性能分析办法及其近似形式的正确性,给出了用户数、退避区间、最大重传次数对功率攀升机制的性能影响,提出了适当增大退避窗口以时延换取能耗的优化策略。

关键词：大规模机器类通信多信道S-ALOHA 功率攀升机制功耗模型时延分析