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视频传输差错时域掩盖方法研究

铁道学报 2004年第4期26卷 55-59页

作者：彭强诸昌钤西南交通大学计算机与通信工程学院四川成都610031

为了克服数字视频在铁路现场传输易出现信息丢失的问题,对视频差错掩盖技术进行了研究,提出一种对付视频传输差错的时域掩盖方法。将参考帧宏块(Macroblock)的运动向量依照其运动趋势外推,评估图像受损区域与这些外推预测宏块之间的相关... 详细信息

为了克服数字视频在铁路现场传输易出现信息丢失的问题,对视频差错掩盖技术进行了研究,提出一种对付视频传输差错的时域掩盖方法。将参考帧宏块(Macroblock)的运动向量依照其运动趋势外推,评估图像受损区域与这些外推预测宏块之间的相关性,估算出受损块的运动向量,实现受损图像区域的掩盖。为克服物体边界不正确替代的缺点,将所提出的算法与改进的边界匹配(BoundaryMatching)算法相结合实现了较为平滑的掩盖。基于H.263.的仿真实验表明,在间隔丢失GOB(GroupofBlock)或整帧图像完全丢失情况下,可以取得较为满意的效果。

关键词：视频监控视频传输差错掩盖差错恢复 H.263.

A numerical study of contact force in competitive evacuation

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Chinese Physics B 2017年第10期26卷 295-301页

作者：林鹏马剑司有亮吴凡雨王国元王建宇 Department of Fire Safety engineering Faculty of Geosciences and Environmental Engineering Southwest Jiaotong University Chengdu 610031 China school of Transportation and Logistics Southwest Jiaotong University Chengdu 610031 China

Crowd force by the pushing or crushing of people has resulted in a number of accidents in recent decades. The aftermath investigations have shown that the physical interaction of a highly competitive crowd could produce dangerous pressure up to 4500 N/m, which leads to compressive asphyxia or even death. In this paper, a numerical model based on discrete element method （DEM） as referenced from granular flow was proposed to model the evacuation process of a group of highly competitive people, in which the movement of people follows Newton＇s second law and the body deformation due to compression follows Hertz contact model. The study shows that the clogs occur periodically and flow rate fluctuates greatly if all people strive to pass through a narrow exit at high enough desired velocity. Two types of contact forces acting on people are studied. The first one, i.e., vector contact force, accounts for the movement of the people following Newton＇s second law. The second one, i.e., scale contact force, accounts for the physical deformation of the human body following the contact law. Simulation shows that the forces chain in crowd flow is turbulent and fragile. A few narrow zones with intense forces are observed in the force field, which is similar to the strain localization observed in granular flow. The force acting on a person could be as high as 4500 N due to force localization, which may be the root cause of compressive asphyxia of people in many crowd incidents.

关键词： crowd flow discrete element method (DEM) contact force force localization

ON THE PERFORMANCE OF DATA-DEPENDENT SUPERIMPOSED TRAINING WITHOUT CYCLIC PREFIX FOR SISO/MIMO SYSTEMS

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Journal of Electronics(china) 2010年第1期27卷 37-42页

作者： Yuan Weina Wang Ping Fan Pingzhi Key Laboratory of Information Coding and Transmission Southwest Jiaotong University Chengdu 610031 China school of Information science and engineering East China Universtiy of Science and Technology Shanghai 200237 China

Compared with channel estimation method based on explicit training sequences,bandwidth is saved for those methods using superimposed training sequences,while it is wasted when Cyclic Prefix(CP) is *** previous work of McLernon,the Mean Square Error(MSE) performance of Data-Dependent Superimposed Training(DDST) without CP for Single-Input Single-Output(SISO) system was analyzed under the assumption that the data-dependent sequence matrix was a circulant matrix and not interfered by *** fact,for the system without CP,the data-dependent sequence matrix is not circulant any more and will be *** paper derives the exact expression of MSE for the system without CP and also gives its extension to Multiple-Input Multiple-Output(MIMO) system without CP.

关键词： Data-Dependent Superimposed Training(DDST) Cyclic Prefix(CP) Multiple-Input-Multiple-Output(MIMO)

Nitrogen isotopic composition of plant-soil in the Loess Plateau and its responding to environmental change

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Chinese science Bulletin 2009年第2期54卷 272-279页

作者： LIU WeiGuo1,2 & WANG Zheng1,3.1 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of sciences, Xi’an 710075, china 2 Xi’an jiaotong {3., school of Human Settlement and Civil engineering, Xi’an 710049, china 3.Graduate {3. of Chinese Academy of sciences, Beijing 100049, china Chinese Acad Sci Inst Earth Environm State Key Lab Loess and Quaternary Geol Xian 710075 Peoples R China.

The nitrogen isotope of soil is of emerging significance as an indicator of climatic change and biogeochemical cycle of nitrogen in nature systems. In this paper, the nitrogen content and isotopic composition of modern ecosystems from arid and semiarid Loess Plateau in northwestern china, including plant roots and surface soil, were determined to investigate trends in δ15N variation of plant roots and soil along a precipitation and temperature gradient in northwestern china under the East Asian Monsoon climate condition. The δ15N values of surface soil from the study area vary from ?1.2‰ to 5.8‰, but from -5.1‰ to 1.9‰ in the plant roots. Our results indicate that (1) although the isotopic compositions of both plant roots and surface soil change with a similar trend along the climate gradient, the apparent nitrogen difference between plant roots and soil existed, with -δ15N values ranging from 0.3. to 7.2‰ with average of 4.1‰; and (2) mean annual precipitation (MAP) is the dominant factor for isotopic composition of plant-soil nitrogen in the Loess Plateau, and the δ15N values are less correlated with MAT; we suggest that nitrogen isotopic composition of soil is a potential tracer for environmental changes.

关键词：氮同位素物理性质化学性质环境论

Assessment of candidate plant DNA barcodes using the Rutaceae family

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science china(Life sciences) 2010年第6期53卷 701-708页

作者： LUO Kun1,2,CHEN ShiLin1,CHEN KeLi2,SONG JingYuan1,YAO Hui1,MA XinYe1,ZHU YingJie3.PANG XiaoHui1,YU Hua1,LI XiWen1,4 & LIU Zhen2 1Institute of Medicinal Plant Development,Peking Union Medical College,Chinese Academy of Medical sciences,Beijing 100193.china 2College of Pharmacy,Hubei university of Chinese Medicine,Wuhan 43.061,china 3.4} of Bioscience and engineering,southwest jiaotong university,chengdu 61003.,china 4Department of Chemistry,Tsinghua university,Beijing 100084,china 1. Institute of Medicinal Plant Development Peking Union Medical College Chinese Academy of Medical Sciences Beijing 100193 China2. College of Pharmacy Hubei University of Chinese Medicine Wuhan 430061 China3. School of Bioscience and Engineering Southwest Jiaotong University Chengdu 610031 China4. Department of Chemistry Tsinghua University Beijing 100084 China

DNA barcoding is a rapidly developing frontier technology that is gaining worldwide ***,seven regions (psbA-trnH,matK,ycf5,rpoC1,rbcL,ITS2,and ITS) with potential for use as DNA barcodes were tested for their ability to identify 3.0 samples of 192 species from 72 genera of the family *** evaluate each barcode’s utility for species authentication,PCR amplification efficiency,genetic divergence,and barcoding gaps were *** found that the ITS2 region exhibited the highest inter-specific divergence,and that this was significantly higher than the intra-specific variation in the "DNA barcoding gap" assessment and Wilcoxon two-sample *** ITS2 locus had the highest identification efficiency among all tested *** a previous study,we found that ITS2 was able to discriminate a wide range of plant taxa,and here we confirmed that ITS2 was also able to discriminate a number of closely related ***,we propose that ITS2 is a promising candidate barcode for plant species identification.

关键词： DNA barcoding ITS2 Rutaceae identification

STUDY FOR NATURAL GAS HYDRATE CONVERSED FROM ICE

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化工学报 2003年第Z1期54卷 23-28页

作者： WANG Shengjie, SHEN Jiandong, HAO Miaoli and LIU Furong (school of environmental and Chemical engineering, Xi’an {3. university, Xi’an 710049, Shaanxi, china) school of environmental and Chemical engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi China

Natural gas hydrates are crystalline clathrate compounds composed of water and gases of small molecular diameters that can be used for storage and transport of natural gas as a novel method. In the paper a series of experiments of aspects and kinetics for hydrate formed from natural gas and ice were carried out on the industrial small scale production apparatus. The experimental results show that formation conditions of hydrate conversed from ice are independent of induction time, and bigger degrees of supersaturation and supercooling improved the driving force and advanced the hydrate *** is also favorable for ice particle conversion to hydrate. In addition, it was found there have an optimal reaction time during hydrate formation.

关键词： natural gas hydrate, formation, ice, supersuturation, supercooling, superpressure

Groundwater arsenic pollution from Inner Mongolia and evidence of its occurrence

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Acta Geochimica 2006年第S1期 9-10页

作者： Hui ZHANG school of environmental science and {3., Shanghai jiaotong university, Shanghai 200240, china

Dimensions of Consumer's Perceived Risk in Online Shopping

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Journal of Electronic science and Technology of china 2004年第3期2卷 177-182页

作者： YE Naiyi (school of Economics and Management, southwest jiaotong university chengdu 61003. {3.) school of Economics and Management Southwest Jiaotong University Chengdu 610031 China

Perceived risk is an important concept in consumer behavior in online shopping. It impedes the adopting online shopping. A structure model with seven factors of consumer's perceived risk in online shopping is developed in this paper. The results have the descriptive power about Chinese consumers' perceived risk in Internet shopping and provide framework for managerial use in china's e-commerce market environment.

关键词： on-line shopping consumer behavior perceived risk

MODELS AND ALGORITHM FOR ROUGH SOLID TRANSPORTATION PROBLEM

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MODELS AND ALGORITHM FOR ROUGH SOLID TRANSPORTATION PROBLEM