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Real-time bottleneck matching in spatial crowdsourcing

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Science China(Information Sciences) 2021年第8期64卷 233-234页

作者： Long LI Lingling WANG weifeng lv State Key Laboratory of Software Development Environment (SKLSDE Lab) and Beijing Advanced Innovation Center for Big Data and Brain Computing (BDBC) Beihang University School of Management and Economics Beijing Institute of Technology

Dear editor,Spatial crowdsourcing(SC) services(e.g., Uber, DiDi, and Meituan) have become popular with smart-phone ***, the online matching problems in real-time spatial data are a key issue in SC [1–4]. Unlike the current one-sided online matching study in real-time spatial data [5], which focuses on minimizing the overall cost of the matching,

关键词： Real-time bottleneck matching in spatial crowdsourcing

Probability tree based passenger flow prediction and its application to the Beijing subway system

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Frontiers of Computer Science 2013年第2期7卷 195-203页

作者： Biao LENG Jiabei ZEN Zhang XIONG weifeng lv Yueliang WAN State Key Laboratory of Software Development Environment Beihang UniversityChina Beijing 100191 School of Computer Science and Engineering Beihang UniversityChina Beijing 100191 Shenzhen Key Laboratory of Data Vitalization (Smart City) Research Institute of Beihang University in Shenzhen China Shenzhen 518057 The Third Research Institute of Ministry of Public Security Run Technologies Co. Ltd. China Beijing 100044

In order to provide citizens with safe, convenient and comfortable services and infrastructure in a metropolis, the prediction of passenger flows in the metro-net of subway system has become more important than ever before. Al- though a great number of prediction methods have been pre- sented in the field of transportation, all of them belong to the station oriented approach, which is not well suited to the Bei- jing subway system. This paper proposes a novel metro-net oriented method, called the probability tree based passenger flow model, which is also based on historic origin-destination （OD） information. First it learns and obtains the appearance probabilities for each kind of OD pair. For the real-time origin datum, the destination datum is calculated, and then several kinds of passenger flow in the metro-net can be pre- dicted by gathering all the contributions. The results of exper- iments, using the historical data of Beijing subway, show that although the proposed method has lower performance than existing prediction approaches for forecasting exit passenger flows, it is able to predict several additional kinds of passen- ger flow in stations and throughout the subway system; and it is a more feasible, suitable, and advanced passenger flow prediction model for Beijing subway system.

关键词： passenger flow prediction tree model origin-destination information

12岁以下儿童肺炎支原体感染后分类抗体变化趋势分析

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医学动物防制 2024年第2期40卷 117-121页

作者：卓雪芽庄健海张间霞蔡惠兴吕微风佛山市中医院广东佛山528000

目的探讨12岁以下儿童肺炎支原体(Mycoplasma pneumoniae,MP)感染后体内IgM和IgG抗体变化趋势,为临床诊治该病提供科学依据。方法选择2017年1月至2019年12月某医院就诊的MP感染患儿240例,其中肺炎支原体肺炎(Mycoplasma pneumoniae pn... 详细信息

目的探讨12岁以下儿童肺炎支原体(Mycoplasma pneumoniae,MP)感染后体内IgM和IgG抗体变化趋势,为临床诊治该病提供科学依据。方法选择2017年1月至2019年12月某医院就诊的MP感染患儿240例,其中肺炎支原体肺炎(Mycoplasma pneumoniae pneumonia, MPP)100例和难治性肺炎支原体肺炎(refractory Mycoplasma pneumoniae pneumonia, RMPP)140例,根据年龄分为0~<3岁组、3~<6岁组、6~<9岁组、9~<12岁组,动态检测MP感染患儿不同时间的体内IgM和IgG抗体水平。结果 0~7d IgM和IgG的抗体阳性率分别为65.2%和50.5%,8~15d IgM抗体阳性率高达100.0%,IgG抗体阳性率为85.2%,16~30d IgM抗体阳性率逐渐降低,IgG抗体阳性率高达100.0%,随后抗体阳性率开始逐渐降低,维持在80.0%;MPP和RMPP组30d内IgM和IgG抗体水平逐渐升高,30d后开始下降,RMPP患儿30d内IgM抗体水平低,而RMPP患儿在发病31~180d的IgG抗体水平较MPP患儿更高,差异有统计学意义(Z=3.324、3.422、2.876,P<0.001);与其他年龄组(0~<3岁组和9~<12岁组)相比,学龄前期儿童和学龄期儿童IgM抗体水平最低,发病31~180d,学龄前期儿童和学龄期儿童IgG抗体水平明显高于其他年龄组,差异有统计学意义(Z=3.021、2.211、2.569,P<0.001)。结论 MP感染的特异性IgM和IgG抗体水平随时间变化呈先上升后下降趋势,RMPP患儿特异性IgG抗体更明显,尤其是学龄前期儿童和学龄期儿童。

关键词：肺炎支原体肺炎难治性肺炎支原体肺炎 IgM IgG 抗体儿童分析

Skip Mode Optimization Based on H.264/AVC

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Skip Mode Optimization Based on H.264/AVC

第25届中国控制与决策会议

作者： Weijie lv Ling Dong weifeng lv School of Electrical Engineering and Automation Tianjin University Department of Strategy and National Defense Mobilization Shijiazhuang Army Command College Shijiazhuang

ISBN: (纸本)9781467355339

Since the introduction of efficient prediction methods, H.264 video/AVC coding standard can achieve considerable higher coding efficiency than the previous standards. However, this comes as a cost of extremely high computational complexity. How to reduce the computation complex and speed up the coding time with little PSNR loss has become a hot spot in this field. In this paper, based on the strong correlation of the adjacent blocks and the current block as well as the relatively low concern about boundary portion of video images, we adjust and relax the restrictions about the zero motion vector in the skip mode to further remove the spatial redundancy. Experimental results with some typical video sequences shows that the proposed methods can reduce encoding time by 6.7% and increase the PSNR slightly with little bitrate degradation.

关键词： H.264 video coding skip mode

来源： cnki会议评论

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大跨度楼面桁架整体提升技术研究

工程技术研究 2024年第2期9卷 106-108页

作者：张宏杰吕伟锋尚文彪周鑫上海宝冶集团有限公司上海200941

液压整体提升技术在大跨度连廊、网架、桁架结构中已得到广泛应用,提升方法也越来越灵活。文章以洛阳市科技馆新馆项目为例,介绍了该工程应用大跨度楼面桁架整体提升技术的特点,以及在设计阶段和提升施工阶段的主要工作内容和注意事项,... 详细信息

液压整体提升技术在大跨度连廊、网架、桁架结构中已得到广泛应用,提升方法也越来越灵活。文章以洛阳市科技馆新馆项目为例,介绍了该工程应用大跨度楼面桁架整体提升技术的特点,以及在设计阶段和提升施工阶段的主要工作内容和注意事项,阐述了该项目在提升后的对接口的焊接技术,分析了该项目大跨度楼面桁架整体提升施工过程模拟和结构监测,旨在保证施工过程和后期结构在使用过程中的安全性。

关键词：大跨度楼面桁架钢结构桁架加固

The GNSS PWV retrieval using non-observation meteorological parameters based on ERA5 and its relation with precipitation

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Geodesy and Geodynamics 2024年第3期15卷 302-313页

作者： weifeng Yang Zhiping Chen Kaiyun lv Pengfei Xia Tieding Lu School of Surveying and Geoinformation Engineering East China University of TechnologyNanchang 330013China Key Laboratory of Mine Environmental Monitoring and Improving around Poyang Lake of Ministry of Natural Resources East China University of TechnologyNanchang 330013China State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430077China Jiangxi Province Engineering Research Center of Surveying Mapping and Geographic InformationNanchang 330025China School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China

The pressure and temperature significantly influence precipitable water vapor(PWV) retrieval. Global Navigation Satellite System(GNSS) PWV retrieval is limited because the GNSS stations lack meteorological sensors. First, this article evaluated the accuracy of pressure and temperature in 68 radiosonde stations in China based on ERA5 Reanalysis data from 2015 to 2019 and compared them with GPT3model. Then, the accuracy of pressure and temperature calculated by ERA5 were estimated in 5 representative IGS stations in China. And the PWV calculated by these meteorological parameters from ERA5(ERA5-PWV) were analyzed. Finally, the relation between ERA5-PWV and precipitation was deeply explored using wavelet coherence analysis in IGS stations. These results indicate that the accuracy of pressure and temperature of ERA5 is better than the GPT3 model. In radiosonde stations, the mean BIAS and MAE of pressure and temperature in ERA5 are-0.41/1.15 hpa and-0.97/2.12 K. And the mean RMSEs are 1.35 hpa and 2.87 K, which improve 74.77% and 40.58% compared with GPT3 model. The errors of pressure and temperature of ERA5 are smaller than the GPT3 model in bjfs, hksl and wuh2, and the accuracy of ERA5-PWV is improved by 18.77% compared with the GPT3 model. In addition, there is a significant positive correlation between ERA5-PWV and precipitation. And precipitation is always associated with the sharp rise of ERA5-PWV, which provides important references for rainfall prediction.

关键词： ERA5 GNSS Precipitable water vapor Precipitation Wavelet coherence analysis

Experimental study of CO_(2) storage in water-flooded oilfields

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Petroleum Research 2017年第4期2卷 378-382页

作者： Zubo Zhang Xu Chen Yuchen Qian Qingjie Liu weifeng lv Manli Luo Xiliang Fan State Key Laboratory of Enhanced Oil Recovery PetroChina Research Institute of Petroleum Exploration and DevelopmentBeijing 100083China Department of Polymer Science and Engineering School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China China University of Petroleum Beijing 102249China

CO_(2) is the main source of greenhouse emission,and the environment problem caused by greenhouse effect has drawn worldwide *** most oilfields in China,a method of waterflooding is usually used to enhance oil recovery,which is favorable to carry out CO_(2) injection *** CO_(2) injection in the water-flooded oilfields can not only store CO_(2),but also enhance the oil *** this article,the coreflooding tests with refined oil were conducted to investigate CO_(2) displacement characteristic in watersaturated formation under different injection rate and water-flooded oil reservoir under different formation pressure and oil saturation,then the CO_(2) storage capacity was *** testing result shows that the displacement efficiency increases with the rise of the CO_(2) injection rate,and the CO_(2) injection can enhance the oil recovery about 15%OOIP under the experimental *** injecting CO_(2) after the waterflooding,the CO_(2) storage capacity increases as the rise of the formation *** core-flooding tests also indicate that when the initial oil saturation of reservoir prior CO_(2) injection is higher,the oil recovery will be higher when injecting the same pore volume(PV)of CO_(2),and the CO_(2) storage capacity will be larger.

关键词： reservoir saturation refined

Micro-pore structure and oil displacement mechanism analysis for deep zone and low permeability reservoir in Mobei oilfield

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Petroleum Research 2018年第2期3卷 159-164页

作者： Haibin Su Ninghong Jia Yandong Yang Zhigang Wang Zhibin Jiang Lijuan Feng Jiru Yang weifeng lv PetroChina Xinjiang Oilfield Research Institute of Exploration and DevelopmentKaramayXinjiang843000China State Key Laboratory of Enhance Oil Recovery PetroChina Research Institute of Petroleum Exploration and DevelopmentBeijing100083China Department of Petroleum Engineering China University of Petroleum(Beijing)Beijing102249China Engineering Technology Research Institute of Xinjiang Oilfield Company KaramayXinjiang843000China Department of Polymer Science and Engineering School of Chemistry and Chemical EngineeringNanjing UniversityNanjing210046China

The Mobei reservoir is a low-permeability-sandstone reservoir,due to differences in pore geometry,it can be divided into two independent reservoirs:A1 reservoir and A2 *** better understanding the water flooding development effects of Mobei reservoir,the mercury intrusion porosimetry,water flooding CT scanning and micro-CT scanning experiments are used in this *** result shows that the reservoir has the strong heterogeneity which is weaken gradually from A1 reservoir to A2 *** pore radius is mainly distributed in the 100e200 microns,the throat radius is mainly distributed in the 1e3 *** water flooding core experiment in each reservoir shows a short water-free oil production period and rapid water cut after *** A2 reservoir core flooding process is similar to piston displacement,the A1 reservoir core flooding process refers to the phenomenon(The fingering phenomenon in the process of core flooding in the A1 reservoir is obvious).The calculated water drive efficiency of the A2 reservoir is 61.2%,which is higher than 49.1%of the A1 *** to the CT scanning process,the Mobei oilfield has low micro displacement efficiency and the A1 reservoir has a smaller spread(sweep area)and higher residual oil saturation.

关键词： Low permeability reservoir Oil displacement efficiency CT scanning Micro-CT Mobei oilfield

Study on the influence of fracture lengths and fracture angles on residual oil distribution based on the slab model

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Petroleum Research 2022年第4期7卷 521-526页

作者： Guihui Lian Zhenhua Ding Liang Chen Xiaoguang Wang Jiru Yang Jigang Zhang Ming Gao weifeng lv Zhenpeng Leng PetroChina Xinjiang Oilfield Research Institute of Exploration and DevelopmentKaramayXinjiang843000China PetroChina Xinjiang Oilfield KaramayXinjiang843000China State Key Laboratory of Enhance Oil Recovery Research Institute of Petroleum Exploration and DevelopmentPetroChinaBeijing100083China Institute of Mechanics Chinese Academy of Sciences100190China

After fracturing in the pilot area,channeling occurs at a low fracture angle(15).Based on the resistance-water saturation relationship,three-dimensional physical simulation methods are used in the laboratory to study the effect of different fracture angles and lengths on the residual oil distribution during the displacement ***,recovery percent,displacement efficiency and expanding sweep co-efficient to the improvement of recovery percent are also *** results show that the fracture angle and length are closely related to the oil saturation distribution in these *** the fracture angle increases,the sweep coefficient decreases(0.2412→0.1463),and the recovery percent also in-creases(46.16→56.88%),but the extent of increase has been reduced(7.96→2.96%).The extension of the fracture length is more prone to have a cross-flow phenomenon;the sweep coefficient is reduced(0.2412→0.1463).Compared to the model with 1/2 oil-water well spacing,the recovery percent is decreased by 14.29%.In different fracture models,the increasable sweep coefficient has a greater impact on oil recovery than the increasable displacement efficiency(71.30→28.70%).

关键词： Slab model Polymer-surfactant flooding Electronic resistance Displacement efficiency Sweep coefficient