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Location and Trajectory Identification from Microblogs

Journal of Computer Science & Technology 2019年第4期34卷 727-746页

作者： Na Ta Guo-liang Li Jun Hu Jian-Hua Feng School of Journalism and Communication Renmin University of ChinaBeijing 100872China Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China Airbnb Network(Beijing)Inc. Beijing 100020China

The rapid development of social networks has resulted in a proliferation of user-generated content(UGC),which can benefit many *** this paper,we study the problem of identifying a user's locations from microblogs,to facilitate effective location-based advertisement and *** the location information in a microblog is incomplete,we cannot get an accurate location from a local *** such,we propose a global location identification method,*** combines multiple microblogs of a user and utilizes them to identify the user's *** not only improves the quality of identifying a user's location but also supplements the location of a microblog so as to obtain an accurate location of a *** facilitate location identification,Glitter organizes points of interest(POIs)into a tree structure where leaf nodes are POIs and non-leaf nodes are segments of POIs,e.g.,countries,cities,and *** the tree structure,Glitter first extracts candidate locations from each microblog of a user which correspond to some tree *** Glitter aggregates these candidate locations and identifies top-κlocations of the *** the identified top-κuser locations,Glitter refines the candidate locations and computes top-κlocations of each *** achieve high recall,we enable fuzzy matching between locations and *** propose an incremental algorithm to support dynamic updates of *** also study how to identify users'trajectories based on the extracted *** propose an effective algorithm to extract high-quality *** results on real-world datasets show that our method achieves high quality and good performance,and scales well.

关键词： location identification microblog trajectory identification

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仿选择性注意机制的语音情感识别算法

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声学学报 2016年第4期41卷 537-544页

作者：梁瑞宇赵力陶华伟王青云邹采荣南京工程学院通信工程学院南京211167 东南大学信息科学工程学院南京210096

有效特征的选取一直都是语音情感识别算法的关键。为此,针对语音情感特征选择与构建的问题,一种仿选择性注意机制的语音情感识别算法被提出。考虑到语音信号的时频特性,算法首先计算语音信号的语谱图;其次,模仿选择性注意机制,计算语谱... 详细信息

有效特征的选取一直都是语音情感识别算法的关键。为此,针对语音情感特征选择与构建的问题,一种仿选择性注意机制的语音情感识别算法被提出。考虑到语音信号的时频特性,算法首先计算语音信号的语谱图;其次,模仿选择性注意机制,计算语谱图的颜色、方向和亮度特征图,归一化后形成特征矩阵;然后,将特征矩阵重排列并进行PCA降维,形成情感识别特征向量;最后,利用改进的支持向量机分类方法进行语音情感识别。对愤怒、恐惧、高兴、悲伤和惊奇5种情感的识别实验显示,基于选择性注意的方法能够获得较好的识别效果,平均识别率为85.44%。相比于韵律特征和音质特征,语音情感识别率至少提高10%;相比于其它语谱特征,识别率提高7%左右。

关键词：语音情感识别选择性注意语音信号特征矩阵识别实验特征图算法类颜色信息特征提取情感特征

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多泵并联给水系统给水泵切换运行规律仿真研究

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核动力工程 2023年第1期44卷 210-216页

作者：田培妤李毅梁铁波王昌朔方华伟中国核动力研究设计院核反应堆系统设计技术重点实验室成都610213

多泵并联给水系统作为核动力系统的主要子系统之一,其给水泵的切换运行规律对系统运行经济性以及系统运行特性至关重要。本研究利用系统仿真支撑软件APROS建立了多泵并联给水系统仿真模型,并依据额定设计值验证了模型的准确性。基于此,... 详细信息

多泵并联给水系统作为核动力系统的主要子系统之一,其给水泵的切换运行规律对系统运行经济性以及系统运行特性至关重要。本研究利用系统仿真支撑软件APROS建立了多泵并联给水系统仿真模型,并依据额定设计值验证了模型的准确性。基于此,通过进行不同切换条件下的线性升、降负荷仿真,对给水泵切换运行规律和系统动态特性进行了研究。研究结果表明,针对本研究对象,其高负荷工况切换点选取为70%额定流量,低负荷工况切换点选取为30%额定流量时,既能获得良好的系统动态响应,还能保持给水泵运行经济性较高。此外,低负荷工况对给水泵切换引入的扰动更为敏感。低负荷工况下,若切换条件选取不当,则会导致降负荷过程中系统触发超压排放。

关键词：多泵并联给水系统 APROS 给水泵切换运行规律仿真

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不同无卤阻燃复合体系对全水发泡聚氨酯泡沫结构与性能的影响

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高分子材料科学与工程 2016年第9期32卷 54-58,64页

作者：莫雪华曾钟邹华维梁梅李杰陈洋四川大学高分子研究所高分子材料工程国家重点实验室四川成都610065 中石油川庆钻探工程有限公司安全环保质量监督检测研究院四川广汉618300

以聚磷酸铵(APP)为主阻燃剂,采用"一步法"工艺制备了环保高效的无卤阻燃全水发泡半硬质聚氨酯泡沫。通过旋转黏度计、扫描电子显微镜、氧指数测量仪、水平垂直燃烧仪、万能材料试验机研究了聚磷酸铵与氢氧化铝(AH)、甲基磷酸二甲酯(DP)... 详细信息

以聚磷酸铵(APP)为主阻燃剂,采用"一步法"工艺制备了环保高效的无卤阻燃全水发泡半硬质聚氨酯泡沫。通过旋转黏度计、扫描电子显微镜、氧指数测量仪、水平垂直燃烧仪、万能材料试验机研究了聚磷酸铵与氢氧化铝(AH)、甲基磷酸二甲酯(DP)的无卤阻燃复合体系对聚氨酯泡沫的发泡行为、结构与性能的影响及规律。研究表明,各无卤阻燃复合体系物料的黏度均随APP用量增加而增大,当APP用量大于30pphp时,黏度增幅变大,尤以添加AH的体系为最。各体系的氧指数均表现出随APP用量增加而增大的趋势,并在APP用量为60pphp时趋于相近值(26.7%),APP/DP体系只能达到垂直燃烧的V-2级别,而只添加APP和APP/AH体系均未达到垂直燃烧级别。只添加APP的体系和APP/AH体系在APP量较高时均因物料黏度大反应过热导致体系发泡不稳定出现内部缺陷,压缩性能下降。

关键词：关键词:无卤阻燃聚磷酸铵氢氧化铝甲基磷酸二甲酯聚氨酯泡沫

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Prototype-based classifier learning for long-tailed visual recognition

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Science China(Information Sciences) 2022年第6期65卷 62-76页

作者： Xiu-Shen WEI Shu-Lin XU Hao CHEN liang XIAO Yuxin PENG School of Computer Science and Engineering Nanjing University of Science and Technology Key Lab of Intelligent Perception and Systems for High-Dimensional Information of Ministry of Education and Jiangsu Key Lab of Image and Video Understanding for Social Security Wangxuan Institute of Computer Technology Peking University State Key Laboratory of Integrated Services Networks Xidian University

In this paper, we tackle the long-tailed visual recognition problem from the categorical prototype perspective by proposing a prototype-based classifier learning(PCL) method. Specifically, thanks to the generalization ability and robustness, categorical prototypes reveal their advantages of representing the category semantics. Coupled with their class-balance characteristic, categorical prototypes also show potential for handling data imbalance. In our PCL, we propose to generate the categorical classifiers based on the prototypes by performing a learnable mapping function. To further alleviate the impact of imbalance on classifier generation, two kinds of classifier calibration approaches are designed from both prototype-level and example-level aspects. Extensive experiments on five benchmark datasets, including the large-scale iNaturalist, Places-LT,and ImageNet-LT, justify that the proposed PCL can outperform state-of-the-arts. Furthermore, validation experiments can demonstrate the effectiveness of tailored designs in PCL for long-tailed problems.

关键词： long-tailed distribution categorical prototype classifier generation classifier calibration class imbalance

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水稻OsPIN1d基因克隆与转化及其在水稻根负向光性中的作用

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西北植物学报 2017年第10期37卷 1896-1903页

作者：梁国斌胥华伟方群莫亿伟江苏理工学院化学与环境工程学院江苏常州213001 河南科技大学农学院河南洛阳471003 绍兴文理学院生命科学学院浙江绍兴312000

生长素极性运输输出载体OsPIN1基因家族可能参与调控水稻根负向光性,其中OsPIN1a和OsPIN1b参与水稻根负向光性已得到证实。为了研究OsPIN1d基因与水稻根负向光性形成的关系,依据GenBank数据库中OsPIN1d(Accession number:BR000830)的核... 详细信息

生长素极性运输输出载体OsPIN1基因家族可能参与调控水稻根负向光性,其中OsPIN1a和OsPIN1b参与水稻根负向光性已得到证实。为了研究OsPIN1d基因与水稻根负向光性形成的关系,依据GenBank数据库中OsPIN1d(Accession number:BR000830)的核苷酸序列,设计特异性引物,通过RT-PCR从水稻根尖的cDNA中扩增出完整的OsPIN1d基因全长。生物信息学分析表明,OsPIN1d的序列全长为1 497bp,编码554个氨基酸,GC含量为64.08%;氨基酸序列多重比对及系统发育树构建表明,OsPIN1d与水稻OsPIN1b、玉米OsPIN4以及拟南芥AtPIN2、OsPIN1c、OsPIN1a和AtPIN1等基因的遗传距离较近。通过构建融合超表达载体pCAMBIA-1301-OsPIN1d∷GFP,转化并获得其转基因水稻,经RT-PCR检测和GUS染色结果显示,外源片段已成功整合到水稻基因组内,并在根部高效表达;受单侧光照射后,转基因水稻种子的根负向光性明显大于野生型,且向光侧OsPIN1d-GFP荧光密度明显弱于背光侧。研究表明,OsPIN1d参与了水稻根负向光性的IAA和NAA的运输,从而促进了根负向光性的形成。

关键词：水稻生长素极性运输 OsPIN1d 负向光性种子根

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A Priority-aware Frequency Domain Polling MAC Protocol for OFDMA-based Networks in Cyber-physical Systems

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IEEE/CAA Journal of Automatica Sinica 2015年第4期2卷 412-421页

作者： Meng Zheng Junru Lin Wei liang Haibin Yu Key Laboratory of Networked Control Systems Shenyang Institute of AutomationChinese Academy of Sciences huawei Technologies Co. Ltd.

Wireless networking in cyber-physical systems (CPSs) is characteristically different from traditional wireless systems due to the harsh radio frequency environment and applications that impose high real-time and reliability constraints. One of the fundamental considerations for enabling CPS networks is the medium access control protocol. To this end, this paper proposes a novel priority-aware frequency domain polling medium access control (MAC) protocol, which takes advantage of an orthogonal frequency-division multiple access (OFDMA) physical layer to achieve instantaneous priority-aware polling. Based on the polling result, the proposed work then optimizes the resource allocation of the OFDMA network to further improve the data reliability. Due to the non-polynomial-complete nature of the OFDMA resource allocation, we propose two heuristic rules, based on which an efficient solution algorithm to the OFDMA resource allocation problem is designed. Simulation results show that the reliability performance of CPS networks is significantly improved because of this work. © 2014 Chinese Association of Automation.

关键词： Access control Embedded systems Frequency domain analysis Medium access control Network layers Orthogonal frequency division multiplexing Polynomials Real time systems Reliability Resource allocation Wireless networks

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黄连素衍生物(氟[^(19)F]HX-01)体外靶向肝癌的初步研究

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生物医学工程学杂志 2017年第2期34卷 253-259页

作者：张彤吴小艾蔡华伟梁梦范成中四川大学华西医院核医学科成都610041

氟[^(18)F]标记黄连素衍生物(氟[^(18)F]HX-01)是一种潜在的正电子发射计算机断层显像(PET)肿瘤显像剂,而能量状态不同、无放射性的标准对照品(氟[^(19)F]HX-01)的物理性质及化学性质与其完全相同。本文通过研究氟[^(19)F]HX-01在体外... 详细信息

氟[^(18)F]标记黄连素衍生物(氟[^(18)F]HX-01)是一种潜在的正电子发射计算机断层显像(PET)肿瘤显像剂,而能量状态不同、无放射性的标准对照品(氟[^(19)F]HX-01)的物理性质及化学性质与其完全相同。本文通过研究氟[^(19)F]HX-01在体外人肝癌细胞和人正常细胞中有无选择性分布的现象,从而为进一步完成活体内氟[^(18)F]HX-01肝癌PET显像奠定基础。本文利用小檗红碱和3-氟丙醇在碱催化作用下,一步反应制备氟[^(19)F]HX01;课题组选取人正常肝细胞(HL-7702)与人肝癌细胞(Hep G2、SMMC-7721)为实验细胞材料,于荧光显微镜下观察[^(19)F]HX-01在细胞内的定位;用细胞增殖活性检测试剂盒(CCK-8)测定氟[^(19)F]HX-01对上述细胞的增殖抑制作用及其对细胞的毒性作用。本文研究结果显示:(1)氟[^(19)F]HX-01与人肝癌细胞Hep G2、SMMC-7721的结合能力明显高于人正常肝细胞HL-7702;(2)氟[^(19)F]HX-01对Hep G2、SMMC-7721以及HL-7702的细胞增殖抑制作用具有剂量依赖效应;(3)氟[^(19)F]HX-01对人正常肝细胞HL-7702的毒性作用较SMMC-7721、Hep G2更低。上述体外研究结果表明:氟[^(19)F]HX-01对人肝癌细胞(Hep G2、SMMC-7721)较人正常肝细胞(HL-7702)具有更高选择性和更高毒性。以此为基础,放射性对照品氟[^(18)F]HX-01有望进一步开发成为潜在肝癌PET显像分子探针。

关键词：氟[19F]HX-01 黄连素人肝癌细胞人正常肝细胞正电子发射计算机断层显像

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Real-time GNSS precise point positioning with smartphones for vehicle navigation

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Satellite Navigation 2022年第3期3卷 140-161,I0004页

作者： Zishen Li liang Wang Ningbo Wang Ran Li Ang Liu Aerospace Information Research Institute(AIR) Chinese Academy of Sciences(CAS)Beijing100094China School of Electronic Electrical and Communicating EngineeringUniversity of Chinese Academy of Sciences19A Yuquan RoadShijingshan DistrictBeijing100049China

The availability of raw Global Navigation Satellite System(GNSS)measurements from Android smart devices gives new possibilities for precise positioning solutions,e.g.,Precise Point Positioning(PPP).However,the accuracy of the PPP with smart devices currently is a few meters due to the poor quality of the raw GNSS measurements in a kinematic scenario and in urban environments,particularly when the smart devices are placed inside *** promote the application of GNSS PPP for land vehicle navigation with smart devices,this contribution studies the real-time PPP with *** data quality analysis and positioning performance validation,two vehicle-based kinematic positioning tests were carried out using two huawei Mate30 smartphones and two huawei P40 smartphones with different installation modes:the vehicle-roof mode with smartphones mounted on the top roof outside the vehicle,and the dashboard mode with smartphones stabilized on the dashboard inside the *** realize high accuracy positioning,we proposed a real-time smartphone PPP method with the data processing strategies adapted for smart *** results show that the real-time PPP can achieve the horizontal positioning accuracy of about 1–1.5 m in terms of root-mean-square and better than 2.5 m at the 95th percentile for the vehicle-based kinematic positioning with the experimental smartphones mounted on the dashboard inside the vehicle,which is the real scenario in vehicle navigation.

关键词： Global Navigation Satellite System Smartphone positioning Precise point positioning Raw GNSS measurements Land vehicle navigation

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An improved GNSS ambiguity best integer equivariant estimation method with Laplacian distribution for urban low-cost RTK positioning

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Satellite Navigation 2024年第1期5卷 109-124页

作者： Ying Liu Wanke Liu Xiaohong Zhang Yantao liang Xianlu Tao Liye Ma School of Geodesy and Geomatics Hubei Luojia LaboratoryWuhan University129 Luoyu RoadWuhan430079HubeiChina Chinese Antarctic Center of Surveying and Mapping Wuhan University129 Luoyu RoadWuhan430079HubeiChina School of Instrument Science and Engineering Southeast UniversityNanjingJiangsuChina The 54 Research Institute of China Electronics Technology Group CorporationShijiazhuang050081HebeiChina State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang050081HebeiChina

The integer least squares(ILS)estimation is commonly used for carrier phase ambiguity resolution(AR).More recently,the best integer equivariant(BIE)estimation has also attracted an attention for complex application scenarios,which exhibits higher reliability by a weighted fusion of integer ***,traditional BIE estimation with Gaussian distribution(GBIE)faces challenges in fully utilizing the advantages of BIE for urban low-cost positioning,mainly due to the presence of outliers and unmodeled *** this end,an improved BIE estimation method with Laplacian distribution(LBIE)is proposed,and several key issues are discussed,including the weight function of LBIE,determination of the candidates included based on the OIA test,and derivation of the variance of LBIE solutions for reliability *** results show that the proposed LBIE method has the positioning accuracy similar to the BIE using multivariate t-distribution(TBIE),and significantly outperforms the ILS-PAR and GBIE *** an urban expressway test with a huawei Mate40 smartphone,the LBIE method has positioning errors of less than 0.5 m in three directions and obtains over 50%improvements compared to the ILS-PAR and GBIE *** an urban canyon test with a low-cost receiver STA8100 produced by STMicroelectronics,the positioning accuracy of LBIE in three directions is 0.112 m,0.107 m,and 0.252 m,respectively,with improvements of 17.6%,27.2%,and 26.1%compared to GBIE,and 23.3%,28.2%,and 30.6%compared to ***,its computational time increases by 30–40%compared to ILS-PAR and is approximately half of that using TBIE.

关键词： Ambiguity resolution Best integer equivariant estimation Laplacian distribution Urban environments Low-cost GNSS receivers Real-time kinematic

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