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Travel Movement Pattern Extraction Based on Social Media Data
SUN Qi, ZHANG Yi, ZHAO Pengfei, WU Mengtong
Acta Scientiarum Naturalium Universitatis Pekinensis    2021, 57 (5): 885-893.   DOI: 10.13209/j.0479-8023.2021.063
Abstract768)   HTML    PDF(pc) (1847KB)(164)       Save
The authors propose a method to extract individual travel spatiotemporal behaviors from social media data, and then mine the group based on massive spatiotemporal behaviors. This study collects more than 40 million global geographic microblogs from users who have visited Suzhou, extracts 88270 tourism trajectories, and identifies 36 classes of inter-city tourism movement patterns in five categories. It is found that the extracted patterns conform to the LCF theoretical model; besides the simple movement patterns, there are more complex composite movement patterns. Based on big data, more accurate tourism movement patterns can be obtained, which helps tourism managers understand tourists’ trends and preferences, adjust destination marketing strategies, optimize tourism resource allocation, and provide better services for tourists.
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Using Mobile Phone Data to Estimate the Temporal-Spatial Distribution and Socioeconomic Attributes of Population in Megacities: A Case Study of Beijing
HAI Xiaodong, LIU Yunshu, ZHAO Pengjun, ZHANG Hui
Acta Scientiarum Naturalium Universitatis Pekinensis    2020, 56 (3): 518-530.   DOI: 10.13209/j.0479-8023.2020.035
Abstract1108)   HTML    PDF(pc) (3739KB)(361)       Save
This study proposes a technique to identify the temporal-spatial distribution and socioeconomic attributes of population by using mobile phone data. This technique has a fine geographic scale, which is called as Spatial Pattern Unit. The study uses Beijing as a case and conducts an empirical application of the technique. Firstly, it investigates the temporal-spatial distribution of population in Beijing by using multiple data sources, including mobile phone data, travel survey data and heat map data. Secondly, it classifies the spatial pattern unit into different categories in terms of socioeconomic attributes of population and travel behavior features. Thirdly, it applies machine learning approach to estimate socioeconomic attributes of population for all spatial pattern units. Finally, it compares and verifies the results of analysis. The approaches and findings would be valuable to monitoring population distribution, locating business services and planning urban infrastructure.
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Jobs-Housing Balance Comparative Analyses with the LBS Data: A Case Study of Beijing
ZHAO Pengjun, CAO Yushu
Acta Scientiarum Naturalium Universitatis Pekinensis    2018, 54 (6): 1290-1302.   DOI: 10.13209/j.0479-8023.2018.077
Abstract793)   HTML    PDF(pc) (4662KB)(332)       Save

Measuring job-housing balance is an important part of job-housing related research, and the dataset applied in previous researches is expanded from survey and census data to LBS data. However, current research lacks comparative studies between different data sources. Beijing urban area is taken as an example to measure and analyze job-housing balance spatial-temporally from different aspects, using different kinds of LBS data, which including heatmap data, Point-of-interest data and Weibo-checkin data. This could provide decision-making reference to improve the job-housing balance. The authors compare the differences in the results of LBS data with the traditional population and economic census data, discusses the causes of the differences, and provides suggestions for further improving the research of LBS data in job-housing relations.

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Survey Research on Residential Building Energy Consumption in Urban and Rural Area of China
WANG Yue, ZHAO Pengjun
Acta Scientiarum Naturalium Universitatis Pekinensis    2018, 54 (1): 162-170.   DOI: 10.13209/j.0479-8023.2017.159
Abstract1088)   HTML11)    PDF(pc) (499KB)(513)       Save

Based on the questionnaire of 10 cities and towns in China, this research has found that there are significant differences between urban and rural area in China through the data analyzing. The survey mainly includes five aspects: energy consumption for heating and cooling, lighting energy consumption, household electricity appliances’ energy consumption, and the energy consumption for cooking. The findings show that the main energy resource are electricity, natural gas and coal and the main energy consuming activities are heating, cooking and household electricity appliances’ consumption. In addition, the results of survey reflect the difference in energy source and consumption structure between urban and rural area. Generally, the per capita energy consumption in urban is 3.2 times of rural life. Gas and electricity are the main energy source in urban area while electricity power and coal have a high proportion in rural residents. The survey results provide important reference for China to implement energy saving policy.

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Common Problems and Technical Innovation of Travel Survey in Old Town: A Case Study in Qianmen Area in Beijing
ZHAO Pengjun, FENG Xiao, LI Shengxiao
Acta Scientiarum Naturalium Universitatis Pekinensis    2016, 52 (3): 486-492.   DOI: 10.13209/j.0479-8023.2015.155
Abstract1233)   HTML    PDF(pc) (407KB)(1167)       Save

This study targets on the practical process of travel survey in Qianmen, Beijing and examines the problems derived from the survey. Their characteristics and the reasons of being generated are stated. The paper focuses on survey organization and its institutional obstacles, the survey design, survey sampling techniques, the choice and training of surveyors and the survey timing. Based on the theoretical researches, the advices towards the innovation of travel survey methods are proposed.

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Urban Expansion Extraction Using Landsat Series Data and DMSP/OLS Nighttime Light Data: A Case Study of Tianjin Area
CHAI Baohui, LI Peijun, ZHANG Ruijie, ZHAO Peng
Acta Scientiarum Naturalium Universitatis Pekinensis    2016, 52 (3): 475-485.   DOI: 10.13209/j.0479-8023.2015.138
Abstract1559)   HTML    PDF(pc) (3037KB)(1928)       Save

By taking Tianjin urban area as an example, a method is proposed to extract urban expansion by combining multi-temporal Landsat TM/ETM+ images and DMSP/OLS nighttime light data, and validated and analyzed. First, the candidate built-up area extent were obtained from DMSP/OLS data. Multitemporal Landsat TM/ETM+ images and derived multivariate textures of the obtained urban extent were classified to extract built-up areas for different dates. Urban expansions for different time intervals were obtained by post-classification comparison method. In addition, the thresholding method was applied to multitemporal DMSP/OLS nighttime light data to extract urban extents for different years and urban expansions of different time intervals were produced. The urban expansion results from DMSP/OLS data and urban statistical data were used to verify the Landsat TM/ETM+ results. The results demonstrate that the combination of Landsat data and DMSP/OLS data effectively reduce the spectral confusion between bare land and urban area and thus produce higher accuracy than useing spectral data from Landsat TM/TM+ images alone in extraction of urban built-up area expansion. Combination of Landsat TM/ETM+ data and DMSP/OLS nighttime light data provides an effective method for urban expansion extraction in mega-city areas.

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Travel Mode Choice Model Accounting for Individual Preference Heterogeneity and Correlation among Choice Alternatives
YANG Liya,ZHAO Pengjun
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract609)      PDF(pc) (438KB)(453)       Save
The authors proposed a new travel mode choice model to overcome the limitation of traditional logit model. Combining generalized extreme value model and latent class model, the authors present a modeling methodology capable of accounting for individual preference heterogeneity and correlation across choice alterna- tives. Travel cost, travel time, parking fee, and waiting time are defined as utility variables for mode choice, while individual income, travel purpose, and travel distance are selected as variables of segment membership function. This model can depict the correlation among choice alternatives and individual preference heterogeneity simultaneously. Using Beijing traffic survey data of 2005, the model parameters are estimated. Estimation results show that the latent class paired nested logit model outperforms the traditional models. Most travelers are cost-sensitive to travel modes, and thus strategies that reduce the travel cost can be more effective than reducing the travel time.
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The Third Series of Cambrian Oolitic Limestones and Their Sedimentary Environment in Beijing, Tianjin, Shanxi and Hebei Provinces, North China
ZHAO Pengyun,LIU Bo,QIN Shan
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract866)      PDF(pc) (4134KB)(483)       Save
The study area, geographically including Beijing, Tianjin, Shanxi and Hebei Provinces, is the main part of the North China Plate. Based on the study of outcrop and thin section observation, the distribution pattern of oolitic limestone and its ooid characteristics are presented. Olitic limestones were widely distributed in the area during the Third Series of Cambrian. Generally, the oolitic limestone elevates in strata gradually from east to west, which indicates that the oolitic limestone is diachronous. Huge oolitic shoals distribute along a western ward bulging belt from north to south, and mainly are composed of concentric ooids. In west of the belt, the thickness of the oolitic limestone decreases rapidly, and the oolitic limestone mainly is composed of radial ooids. In east of the belt, the oolitic limestone thins gradually, with majority grains of concentric ooids. The marine transgression during the Third Epoch of Cambrian took place from east to west on the North China Plate. In this background, the inner ramp ooid shoals developed in the central belt of the study area, with open sea in the east and shoal back tidal flat in the west.
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Indicator Kriging Study of Multivariate Information in Temporal-spatial Domain
XIAO Bin,PAN Mao,ZHAO Pengda,HOU Jingru
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract649)            Save
Based on indicator kriging and the theory of coregionalization in spatial domain, indicator kriging of multivariate information in temporal-spatial domain was discussed. Authors mainly studied second order moment of indicator kriging, indicator cokriging, indicator principal component kriging and order relation in temporal-spatial domain.
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Geostatistical Study of Au-comprehensive Chemical Exploratory Anomaly at Guilaizhuang Au-deposit
XIAO Bin,ZHAO Pengda,HOU Jingru
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract645)            Save
Synthesizing multivariate information, Au-comprehensive chemical exploratory anomaly was discussed with geostatistical methods at Guilaizhuang Au-deposit. Main work included: using cokriging, influence of regional chemical elements (W, As, Sb) to Au-anomaly and Au-mineralization has been studied. Contribution of g(Au/Ag) to Au-anomaly has been probed into making use of indicator kriging and some suggestions for the future work have been given.
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