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Ci Song
Institute of Geography Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China

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Journal article
Published: 27 July 2021 in Urban Forestry & Urban Greening
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Urban parks are vital ecological recreational places, and their spatial evolution has a certain influence on the ecological environment and quality of citizens’ daily life. Taking Beijing as an example, this paper firstly explores the dynamic evolution of urban parks in Beijing by comparing spatial distribution characteristics in three time points of 2005, 2010 and 2017. Besides changes in number and area, the spatial structure and accessibility are examined by the methods of directional distribution, kernel density estimation and network analysis. Then three-factor analysis method is used to explain the evolution mechanism. The results reveal that there exist obvious and continuous growths in urban parks regardless of quantity, area or accessibility. According to the core-periphery spatial distribution pattern, Beijing has gradually formed a systematic green recreational network, and the service area of urban parks by walking within 30 min is 58.6% of total area. Stability factors, dynamic factors and random factors play important roles during the spatial evolution of urban parks through restraint mechanism, supply-demand mechanism and triggering mechanism respectively. The findings offer both theoretical construct and policy recommendations for the development and sustainability of urban parks in Beijing and other rapidly urbanizing cities with high population densities.

ACS Style

Shuying Zhang; Jiaming Liu; Ci Song; Chung-Shing Chan; Tao Pei; Yu Wenting; Zhang Xin. Spatial-temporal distribution characteristics and evolution mechanism of urban parks in Beijing, China. Urban Forestry & Urban Greening 2021, 64, 127265 .

AMA Style

Shuying Zhang, Jiaming Liu, Ci Song, Chung-Shing Chan, Tao Pei, Yu Wenting, Zhang Xin. Spatial-temporal distribution characteristics and evolution mechanism of urban parks in Beijing, China. Urban Forestry & Urban Greening. 2021; 64 ():127265.

Chicago/Turabian Style

Shuying Zhang; Jiaming Liu; Ci Song; Chung-Shing Chan; Tao Pei; Yu Wenting; Zhang Xin. 2021. "Spatial-temporal distribution characteristics and evolution mechanism of urban parks in Beijing, China." Urban Forestry & Urban Greening 64, no. : 127265.

Journal article
Published: 25 March 2021 in Cities
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Restaurants are basic urban amenities. With the dynamic evolution of cities, restaurants rise and fall: new restaurants may open (birth), and existing restaurants may close (death). Analyzing the rise and fall of restaurants may assist urban dynamics exploration and urban policy assessment. Location is crucial for restaurant success. Roles of locational factors in restaurants' rise and fall were empirically explored in this case study of Beijing based on point of interest (POI) data, a more available and universal data source than conventional statistics used by previous studies. We characterized restaurant birth and death through matching POI data across years, examined their spatial patterns, and regressed restaurant distribution, birth, and death against various locational factors with count regression models. The rise and fall of restaurants revealed the impact of policies relieving Beijing of functions non-essential to its role as China's capital. Regressions suggested four roles of locational factors: 1) Promoting factors, including accessibility, commercial land use, and building capacity; 2) Hindering factors, namely, existing restaurant density; 3) Stabilizing factors, i.e. house price; and 4) Irrelevant factors, including population and residential and institutional land use. Our findings may provide practical advice for restaurant operators and urban policy makers.

ACS Style

Mingbo Wu; Tao Pei; Wenlai Wang; Sihui Guo; Ci Song; Jie Chen; Chenghu Zhou. Roles of locational factors in the rise and fall of restaurants: A case study of Beijing with POI data. Cities 2021, 113, 103185 .

AMA Style

Mingbo Wu, Tao Pei, Wenlai Wang, Sihui Guo, Ci Song, Jie Chen, Chenghu Zhou. Roles of locational factors in the rise and fall of restaurants: A case study of Beijing with POI data. Cities. 2021; 113 ():103185.

Chicago/Turabian Style

Mingbo Wu; Tao Pei; Wenlai Wang; Sihui Guo; Ci Song; Jie Chen; Chenghu Zhou. 2021. "Roles of locational factors in the rise and fall of restaurants: A case study of Beijing with POI data." Cities 113, no. : 103185.

Journal article
Published: 20 February 2021 in ISPRS International Journal of Geo-Information
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People spend more than 80% of their time in indoor spaces, such as shopping malls and office buildings. Indoor trajectories collected by indoor positioning devices, such as WiFi and Bluetooth devices, can reflect human movement behaviors in indoor spaces. Insightful indoor movement patterns can be discovered from indoor trajectories using various clustering methods. These methods are based on a measure that reflects the degree of similarity between indoor trajectories. Researchers have proposed many trajectory similarity measures. However, existing trajectory similarity measures ignore the indoor movement constraints imposed by the indoor space and the characteristics of indoor positioning sensors, which leads to an inaccurate measure of indoor trajectory similarity. Additionally, most of these works focus on the spatial and temporal dimensions of trajectories and pay less attention to indoor semantic information. Integrating indoor semantic information such as the indoor point of interest into the indoor trajectory similarity measurement is beneficial to discovering pedestrians having similar intentions. In this paper, we propose an accurate and reasonable indoor trajectory similarity measure called the indoor semantic trajectory similarity measure (ISTSM), which considers the features of indoor trajectories and indoor semantic information simultaneously. The ISTSM is modified from the edit distance that is a measure of the distance between string sequences. The key component of the ISTSM is an indoor navigation graph that is transformed from an indoor floor plan representing the indoor space for computing accurate indoor walking distances. The indoor walking distances and indoor semantic information are fused into the edit distance seamlessly. The ISTSM is evaluated using a synthetic dataset and real dataset for a shopping mall. The experiment with the synthetic dataset reveals that the ISTSM is more accurate and reasonable than three other popular trajectory similarities, namely the longest common subsequence (LCSS), edit distance on real sequence (EDR), and the multidimensional similarity measure (MSM). The case study of a shopping mall shows that the ISTSM effectively reveals customer movement patterns of indoor customers.

ACS Style

Jin Zhu; Dayu Cheng; Weiwei Zhang; Ci Song; Jie Chen; Tao Pei. A New Approach to Measuring the Similarity of Indoor Semantic Trajectories. ISPRS International Journal of Geo-Information 2021, 10, 90 .

AMA Style

Jin Zhu, Dayu Cheng, Weiwei Zhang, Ci Song, Jie Chen, Tao Pei. A New Approach to Measuring the Similarity of Indoor Semantic Trajectories. ISPRS International Journal of Geo-Information. 2021; 10 (2):90.

Chicago/Turabian Style

Jin Zhu; Dayu Cheng; Weiwei Zhang; Ci Song; Jie Chen; Tao Pei. 2021. "A New Approach to Measuring the Similarity of Indoor Semantic Trajectories." ISPRS International Journal of Geo-Information 10, no. 2: 90.

Journal article
Published: 29 January 2021 in Cities
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Job-housing flows are among the most important travel flows in a city. Therefore, it is essential to measure the extent to which the job-housing flow distribution covers the city space, which can be used as evidence for evaluating the land use status and transportation system. Existing studies have analyzed the spatial distribution of job-housing flows in terms of where and how the flows are aggregated in the city, but they have not revealed the extent to which the flow distribution fills the city space. In this study, we introduce a fractal dimension to measure the space-filling degree of the job-housing flows, which is defined based on the flow space, with the flow being the basic element. Because the flow fractal dimension is independent of the observation scale, we compared the box-counting dimensions of job-housing flows in Beijing and Shenzhen using mobile phone data. The results demonstrated that the fractal dimension was substantially higher in Beijing than in Shenzhen, indicating that the job and home distributions fill more space in Beijing, and the links between the job and home locations are more disordered and irregular in Beijing. These results are related to the more crammed urban land use and higher commuting demand from the suburbs to the city center.

ACS Style

Sihui Guo; Tao Pei; Shuyun Xie; Ci Song; Jie Chen; Yaxi Liu; Hua Shu; Xi Wang; Ling Yin. Fractal dimension of job-housing flows: A comparison between Beijing and Shenzhen. Cities 2021, 112, 103120 .

AMA Style

Sihui Guo, Tao Pei, Shuyun Xie, Ci Song, Jie Chen, Yaxi Liu, Hua Shu, Xi Wang, Ling Yin. Fractal dimension of job-housing flows: A comparison between Beijing and Shenzhen. Cities. 2021; 112 ():103120.

Chicago/Turabian Style

Sihui Guo; Tao Pei; Shuyun Xie; Ci Song; Jie Chen; Yaxi Liu; Hua Shu; Xi Wang; Ling Yin. 2021. "Fractal dimension of job-housing flows: A comparison between Beijing and Shenzhen." Cities 112, no. : 103120.

Journal article
Published: 18 November 2020 in IEEE Access
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The first wave of the 2019 novel coronavirus (COVID-19) epidemic in China showed there was a lag between the reduction in human mobility and the decline in COVID-19 transmission and this lag was different in cities. A prolonged lag would cause public panic and reflect the inefficiency of control measures. This study aims to quantify this time-lag effect and reveal its influencing socio-demographic and environmental factors, which is helpful to policymaking in controlling COVID-19 and other potential infectious diseases in the future. We combined city-level mobility index and new case time series for 80 most affected cities in China from Jan 17 to Feb 29, 2020. Cross correlation analysis and spatial autoregressive model were used to estimate the lag length and determine influencing factors behind it, respectively. The results show that mobility is strongly correlated with COVID-19 transmission in most cities with lags of 10 days (interquartile range 8 – 11 days) and correlation coefficients of 0.68±0.12. This time-lag is consistent with the incubation period plus time for reporting. Cities with a shorter lag appear to have a shorter epidemic duration. This lag is shorter in cities with larger volume of population flow from Wuhan, higher designated hospitals density and urban road density while economically advantaged cities tend to have longer time lags. These findings suggest that cities with compact urban structure should strictly adhere to human mobility restrictions, while economically prosperous cities should also strengthen other non-pharmaceutical interventions to control the spread of the virus.

ACS Style

Wang Xi; Tao Pei; Qiyong Liu; Ci Song; Yaxi Liu; Xiao Chen; Jia Ma; Zhixin Zhang. Quantifying the Time-Lag Effects of Human Mobility on the COVID-19 Transmission: A Multi-City Study in China. IEEE Access 2020, 8, 216752 -216761.

AMA Style

Wang Xi, Tao Pei, Qiyong Liu, Ci Song, Yaxi Liu, Xiao Chen, Jia Ma, Zhixin Zhang. Quantifying the Time-Lag Effects of Human Mobility on the COVID-19 Transmission: A Multi-City Study in China. IEEE Access. 2020; 8 (99):216752-216761.

Chicago/Turabian Style

Wang Xi; Tao Pei; Qiyong Liu; Ci Song; Yaxi Liu; Xiao Chen; Jia Ma; Zhixin Zhang. 2020. "Quantifying the Time-Lag Effects of Human Mobility on the COVID-19 Transmission: A Multi-City Study in China." IEEE Access 8, no. 99: 216752-216761.

Journal article
Published: 28 August 2020 in Applied Sciences
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As a symbol of Chinese culture, Chinese traditional-style architecture defines the unique characteristics of Chinese cities. The visual qualities and spatial distribution of architecture represent the image of a city, which affects the psychological states of the residents and can induce positive or negative social outcomes. Hence, it is important to study the visual perception of Chinese traditional-style buildings in China. Previous works have been restricted by the lack of data sources and techniques, which were not quantitative and comprehensive. In this paper, we proposed a deep learning model for automatically predicting the presence of Chinese traditional-style buildings and developed two view indicators to quantify the pedestrians’ visual perceptions of buildings. Using this model, Chinese traditional-style buildings were automatically segmented in streetscape images within the Fifth Ring Road of Beijing and then the perception of Chinese traditional-style buildings was quantified with two view indictors. This model can also help to automatically predict the perception of Chinese traditional-style buildings for new urban regions in China, and more importantly, the two view indicators provide a new quantitative method for measuring the urban visual perception in street level, which is of great significance for the quantitative research of tourism route and urban planning.

ACS Style

Liying Zhang; Tao Pei; Xi Wang; Mingbo Wu; Ci Song; Sihui Guo; Yijin Chen. Quantifying the Urban Visual Perception of Chinese Traditional-Style Building with Street View Images. Applied Sciences 2020, 10, 5963 .

AMA Style

Liying Zhang, Tao Pei, Xi Wang, Mingbo Wu, Ci Song, Sihui Guo, Yijin Chen. Quantifying the Urban Visual Perception of Chinese Traditional-Style Building with Street View Images. Applied Sciences. 2020; 10 (17):5963.

Chicago/Turabian Style

Liying Zhang; Tao Pei; Xi Wang; Mingbo Wu; Ci Song; Sihui Guo; Yijin Chen. 2020. "Quantifying the Urban Visual Perception of Chinese Traditional-Style Building with Street View Images." Applied Sciences 10, no. 17: 5963.

Journal article
Published: 31 January 2020 in Nature Communications
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Inadequate water quality can mean that water is unsuitable for a variety of human uses, thus exacerbating freshwater scarcity. Previous large-scale water scarcity assessments mostly focused on the availability of sufficient freshwater quantity for providing supplies, but neglected the quality constraints on water usability. Here we report a comprehensive nationwide water scarcity assessment in China, which explicitly includes quality requirements for human water uses. We highlight the necessity of incorporating water scarcity assessment at multiple temporal and geographic scales. Our results show that inadequate water quality exacerbates China’s water scarcity, which is unevenly distributed across the country. North China often suffers water scarcity throughout the year, whereas South China, despite sufficient quantities, experiences seasonal water scarcity due to inadequate quality. Over half of the population are affected by water scarcity, pointing to an urgent need for improving freshwater quantity and quality management to cope with water scarcity.

ACS Style

Ting Ma; Siao Sun; Guangtao Fu; Jim W. Hall; Yong Ni; Lihuan He; Jiawei Yi; Na Zhao; Yunyan Du; Tao Pei; Weiming Cheng; Ci Song; Chuanglin Fang; Chenghu Zhou. Pollution exacerbates China’s water scarcity and its regional inequality. Nature Communications 2020, 11, 1 -9.

AMA Style

Ting Ma, Siao Sun, Guangtao Fu, Jim W. Hall, Yong Ni, Lihuan He, Jiawei Yi, Na Zhao, Yunyan Du, Tao Pei, Weiming Cheng, Ci Song, Chuanglin Fang, Chenghu Zhou. Pollution exacerbates China’s water scarcity and its regional inequality. Nature Communications. 2020; 11 (1):1-9.

Chicago/Turabian Style

Ting Ma; Siao Sun; Guangtao Fu; Jim W. Hall; Yong Ni; Lihuan He; Jiawei Yi; Na Zhao; Yunyan Du; Tao Pei; Weiming Cheng; Ci Song; Chuanglin Fang; Chenghu Zhou. 2020. "Pollution exacerbates China’s water scarcity and its regional inequality." Nature Communications 11, no. 1: 1-9.

Journal article
Published: 01 January 2020 in IEEE Access
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ACS Style

Ci Song; Tao Pei; Hua Shu. Identifying Flow Clusters Based on Density Domain Decomposition. IEEE Access 2020, 8, 5236 -5243.

AMA Style

Ci Song, Tao Pei, Hua Shu. Identifying Flow Clusters Based on Density Domain Decomposition. IEEE Access. 2020; 8 ():5236-5243.

Chicago/Turabian Style

Ci Song; Tao Pei; Hua Shu. 2020. "Identifying Flow Clusters Based on Density Domain Decomposition." IEEE Access 8, no. : 5236-5243.

Journal article
Published: 09 December 2019 in Sustainability
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The fine-grained population distributions of different age groups are crucial for urban planning applications. With the development of information and communication technology (ICT), detailed population data retrieved from various big data sources, especially on a fine scale, have been extensively used for urban planning. However, studies estimating the detailed population distributions of different age groups are still lacking. This study constructs a framework to generate fine-grained population data for different age groups and explores the influence of various factors on the distributions of different age groups. The population is divided into the following four age groups: (1) early adulthood people: 18 ≤ age ≤ 24, (2) young people: 25 ≤ age ≤ 39, (3) middle-aged people: 40 ≤ age ≤ 59, and (4) elderly people: 60 ≤ age. The results indicate that education and accommodation factors have a major influence on the distributions of early adulthood and elderly people, respectively. Business, restaurant, and accommodation factors are the main factors influencing the population distributions of young and middle-aged people. The accommodation factor plays a major controlling role at night, and its explanatory power gradually decreases during the day, while the explanatory powers of the business and restaurant factors increase and become leading factors during the day. Specifically, the hospital factor has a greater effect on the distribution of elderly people. The entertainment factor has very little explanatory power for the population distributions of the different age groups.

ACS Style

Wenlai Wang; Tao Pei; Jie Chen; Ci Song; Xi Wang; Hua Shu; Ting Ma; Yunyan Du. Population Distributions of Age Groups and Their Influencing Factors Based on Mobile Phone Location Data: A Case Study of Beijing, China. Sustainability 2019, 11, 7033 .

AMA Style

Wenlai Wang, Tao Pei, Jie Chen, Ci Song, Xi Wang, Hua Shu, Ting Ma, Yunyan Du. Population Distributions of Age Groups and Their Influencing Factors Based on Mobile Phone Location Data: A Case Study of Beijing, China. Sustainability. 2019; 11 (24):7033.

Chicago/Turabian Style

Wenlai Wang; Tao Pei; Jie Chen; Ci Song; Xi Wang; Hua Shu; Ting Ma; Yunyan Du. 2019. "Population Distributions of Age Groups and Their Influencing Factors Based on Mobile Phone Location Data: A Case Study of Beijing, China." Sustainability 11, no. 24: 7033.

Journal article
Published: 20 October 2019 in Sustainability
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As important modern tourist destinations, cities play a critical role in developing agglomerated tourism elements and promoting urban life quality. An in-depth exploration of tourist flow patterns between destination cities can reflect the dynamic trends of the inbound tourist market. This is significant for the development of tourism markets and innovation in tourism products. To this end, photos with geographical and corresponding metadata covering the entire country from 2011 to 2017 are used to explore the spatial characteristics of China’s inbound tourist flow, the spatial patterns of tourist movement, and the tourist destination cities group based on data mining techniques, including the Markov chain, a frequent-pattern-mining algorithm, and a community detection algorithm. Our findings show that: (1) the strongest flow of inbound tourists is between Beijing and Shanghai. These two cities, along with Xi’an and Guiling, form a “double-triangle” framework, (2) the travel between emerging destination cities in Central and Western China have gradually become frequently selected itineraries, and, (3) based on the flow intensity, inbound tourist destination cities can be divided into nine groups. This study provides a valuable reference for the development of China’s inbound tourism market.

ACS Style

Jing Qin; Ci Song; Mingdi Tang; Youyin Zhang; Jinwei Wang. Exploring the Spatial Characteristics of Inbound Tourist Flows in China Using Geotagged Photos. Sustainability 2019, 11, 5822 .

AMA Style

Jing Qin, Ci Song, Mingdi Tang, Youyin Zhang, Jinwei Wang. Exploring the Spatial Characteristics of Inbound Tourist Flows in China Using Geotagged Photos. Sustainability. 2019; 11 (20):5822.

Chicago/Turabian Style

Jing Qin; Ci Song; Mingdi Tang; Youyin Zhang; Jinwei Wang. 2019. "Exploring the Spatial Characteristics of Inbound Tourist Flows in China Using Geotagged Photos." Sustainability 11, no. 20: 5822.

Journal article
Published: 28 August 2019 in Landscape and Urban Planning
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Many countries are facing an aging population crisis, triggering major concerns over how to best provide services for older people. Parks are an important public service resource for older people living in urban areas. Due to the uneven geographic distribution of parks within a city, elderly people may have unequal access to this resource, based on their socioeconomic status. This park access issue has been under-examined among older populations, who may be more vulnerable and have limited physical mobility. The two-step floating catchment area (2SFCA) method has been increasingly used to measure access to parks; however, a “catchment area,” defined as the traveling distance to a resource, may be biased against older subjects, due to the lack of behavior-based information within traditional census data. To bridge this methodological gap within the literature, this study sought to estimate park access for the elderly, using the 2SFCA method and new data sources (mobile phone data), in order to determine if older people experience inequitable park access owing to their socioeconomic status. Based on a spatial and multivariate analysis of data collected in Beijing, we find that housing price, the distance to commercial areas and greenspaces are significant influencing factors of the park accessibility; elderly people living in newly built areas, the lower the housing price, the lower accessibility to parks. These findings may assist municipal policy makers in the planning and management of park access for aging citizens.

ACS Style

Sihui Guo; Ci Song; Tao Pei; Yaxi Liu; Ting Ma; Yunyan Du; Jie Chen; Zide Fan; Xianli Tang; Yong Peng; Yanbin Wang. Accessibility to urban parks for elderly residents: Perspectives from mobile phone data. Landscape and Urban Planning 2019, 191, 103642 .

AMA Style

Sihui Guo, Ci Song, Tao Pei, Yaxi Liu, Ting Ma, Yunyan Du, Jie Chen, Zide Fan, Xianli Tang, Yong Peng, Yanbin Wang. Accessibility to urban parks for elderly residents: Perspectives from mobile phone data. Landscape and Urban Planning. 2019; 191 ():103642.

Chicago/Turabian Style

Sihui Guo; Ci Song; Tao Pei; Yaxi Liu; Ting Ma; Yunyan Du; Jie Chen; Zide Fan; Xianli Tang; Yong Peng; Yanbin Wang. 2019. "Accessibility to urban parks for elderly residents: Perspectives from mobile phone data." Landscape and Urban Planning 191, no. : 103642.

Journal article
Published: 26 July 2019 in ISPRS International Journal of Geo-Information
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The decomposition of a point process is useful for the analysis of spatial patterns and in the discovery of potential mechanisms of geographic phenomena. However, when a local repulsive cluster is present in a complex heterogeneous point process, the traditional solution, which is based on clustering, may be invalid for decomposition because a repulsive pattern is not subject to a specific probability distribution function and the effects of aggregative and repulsive components may be counterbalanced. To solve this problem, this paper proposes a method of decomposing repulsive clusters in complex point processes with multiple heterogeneous components. A repulsive cluster is defined as a set of repulsive density-connected points that are separated by a certain distance at a small scale and aggregated at a large scale simultaneously. The H-function is used to identify repulsive clusters by determining the repulsive distance and extracting repulsive points for further clustering. Through simulation experiments based on three datasets, the proposed method has been shown to effectively perform repulsive cluster decomposition in heterogeneous point processes. A case study of the point of interest (POI) dataset in Beijing also indicates that the method can identify meaningful repulsive clusters from types of POIs that represent different service characteristics of shops in different local regions.

ACS Style

Ci Song; Tao Pei. Decomposition of Repulsive Clusters in Complex Point Processes with Heterogeneous Components. ISPRS International Journal of Geo-Information 2019, 8, 326 .

AMA Style

Ci Song, Tao Pei. Decomposition of Repulsive Clusters in Complex Point Processes with Heterogeneous Components. ISPRS International Journal of Geo-Information. 2019; 8 (8):326.

Chicago/Turabian Style

Ci Song; Tao Pei. 2019. "Decomposition of Repulsive Clusters in Complex Point Processes with Heterogeneous Components." ISPRS International Journal of Geo-Information 8, no. 8: 326.

Journal article
Published: 05 October 2018 in Landscape and Urban Planning
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The rapid process of urbanization aggravates the imbalance between the supply and demand of urban public services. Urban parks are among the most important urban public services, and their use efficiency has been an important index for urban planning. Therefore, it is essential to estimate well their service area and influencing factors. Traditional survey data used to analyze the characteristics of urban park services are limited by small samples and high cost. Owing to thriving information communication technologies, vast amounts of human activity data have become available that enable understanding of human travel behavior. In this study, we analyzed a park service area, which is defined as the zone of influence of individual parks, in Beijing, and the factors that influence the service area. First, the service area was estimated using 1-SDE based on mobile phone signaling data. A multiple linear regression model was then used to analyze the influence of factors on the park service area. The results show that (1) external factors including population density, the number of commercial facilities, and traffic convenience have significant influences on the park service area; (2) employment places positively influence the park service area on the weekday; and (3) other factors such as park design and park reputation had inconsistent effects on the park service area, in either sign or significance, regarding the weekday and the weekend. The findings of this study will be of practical value when designing parks or undertaking city planning in the future.

ACS Style

Sihui Guo; Gege Yang; Tao Pei; Ting Ma; Ci Song; Hua Shu; Yunyan Du; Chenghu Zhou. Analysis of factors affecting urban park service area in Beijing: Perspectives from multi-source geographic data. Landscape and Urban Planning 2018, 181, 103 -117.

AMA Style

Sihui Guo, Gege Yang, Tao Pei, Ting Ma, Ci Song, Hua Shu, Yunyan Du, Chenghu Zhou. Analysis of factors affecting urban park service area in Beijing: Perspectives from multi-source geographic data. Landscape and Urban Planning. 2018; 181 ():103-117.

Chicago/Turabian Style

Sihui Guo; Gege Yang; Tao Pei; Ting Ma; Ci Song; Hua Shu; Yunyan Du; Chenghu Zhou. 2018. "Analysis of factors affecting urban park service area in Beijing: Perspectives from multi-source geographic data." Landscape and Urban Planning 181, no. : 103-117.

Journal article
Published: 10 September 2018 in International Journal of Geographical Information Science
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ACS Style

Ci Song; Tao Pei; Ting Ma; Yunyan Du; Hua Shu; Sihui Guo; Zide Fan. Detecting arbitrarily shaped clusters in origin-destination flows using ant colony optimization. International Journal of Geographical Information Science 2018, 33, 134 -154.

AMA Style

Ci Song, Tao Pei, Ting Ma, Yunyan Du, Hua Shu, Sihui Guo, Zide Fan. Detecting arbitrarily shaped clusters in origin-destination flows using ant colony optimization. International Journal of Geographical Information Science. 2018; 33 (1):134-154.

Chicago/Turabian Style

Ci Song; Tao Pei; Ting Ma; Yunyan Du; Hua Shu; Sihui Guo; Zide Fan. 2018. "Detecting arbitrarily shaped clusters in origin-destination flows using ant colony optimization." International Journal of Geographical Information Science 33, no. 1: 134-154.

Original article
Published: 19 July 2018 in Liver International
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Metabolic factors play an important role in presence of NAFLD among Chinese CHB patients. However, viral replication factors are not related to NAFLD except among those with concurrent type 2 DM. This article is protected by copyright. All rights reserved.

ACS Style

Liguo Zhu; Jie Jiang; Xiangjun Zhai; Aileen Baecker; Hong Peng; Jiao Qian; Minghao Zhou; Ci Song; Yan Zhou; Jianfang Xu; Hongjian Liu; Dong Hang; Zhibin Hu; Hongbing Shen; Zuo-Feng Zhang; Fengcai Zhu. Hepatitis B virus infection and risk of non-alcoholic fatty liver disease: A population-based cohort study. Liver International 2018, 39, 70 -80.

AMA Style

Liguo Zhu, Jie Jiang, Xiangjun Zhai, Aileen Baecker, Hong Peng, Jiao Qian, Minghao Zhou, Ci Song, Yan Zhou, Jianfang Xu, Hongjian Liu, Dong Hang, Zhibin Hu, Hongbing Shen, Zuo-Feng Zhang, Fengcai Zhu. Hepatitis B virus infection and risk of non-alcoholic fatty liver disease: A population-based cohort study. Liver International. 2018; 39 (1):70-80.

Chicago/Turabian Style

Liguo Zhu; Jie Jiang; Xiangjun Zhai; Aileen Baecker; Hong Peng; Jiao Qian; Minghao Zhou; Ci Song; Yan Zhou; Jianfang Xu; Hongjian Liu; Dong Hang; Zhibin Hu; Hongbing Shen; Zuo-Feng Zhang; Fengcai Zhu. 2018. "Hepatitis B virus infection and risk of non-alcoholic fatty liver disease: A population-based cohort study." Liver International 39, no. 1: 70-80.

Journal article
Published: 01 May 2018 in Computers, Environment and Urban Systems
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ACS Style

Zide Fan; Tao Pei; Ting Ma; Yunyan Du; Ci Song; Zhang Liu; Chenghu Zhou. Estimation of urban crowd flux based on mobile phone location data: A case study of Beijing, China. Computers, Environment and Urban Systems 2018, 69, 114 -123.

AMA Style

Zide Fan, Tao Pei, Ting Ma, Yunyan Du, Ci Song, Zhang Liu, Chenghu Zhou. Estimation of urban crowd flux based on mobile phone location data: A case study of Beijing, China. Computers, Environment and Urban Systems. 2018; 69 ():114-123.

Chicago/Turabian Style

Zide Fan; Tao Pei; Ting Ma; Yunyan Du; Ci Song; Zhang Liu; Chenghu Zhou. 2018. "Estimation of urban crowd flux based on mobile phone location data: A case study of Beijing, China." Computers, Environment and Urban Systems 69, no. : 114-123.

Journal article
Published: 22 November 2016 in Sensors
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Queuing is common in urban public places. Automatically monitoring and predicting queuing time can not only help individuals to reduce their wait time and alleviate anxiety but also help managers to allocate resources more efficiently and enhance their ability to address emergencies. This paper proposes a novel method to estimate and predict queuing time in indoor environments based on WiFi positioning data. First, we use a series of parameters to identify the trajectories that can be used as representatives of queuing time. Next, we divide the day into equal time slices and estimate individuals’ average queuing time during specific time slices. Finally, we build a nonstandard autoregressive (NAR) model trained using the previous day’s WiFi estimation results and actual queuing time to predict the queuing time in the upcoming time slice. A case study comparing two other time series analysis models shows that the NAR model has better precision. Random topological errors caused by the drift phenomenon of WiFi positioning technology (locations determined by a WiFi positioning system may drift accidently) and systematic topological errors caused by the positioning system are the main factors that affect the estimation precision. Therefore, we optimize the deployment strategy during the positioning system deployment phase and propose a drift ratio parameter pertaining to the trajectory screening phase to alleviate the impact of topological errors and improve estimates. The WiFi positioning data from an eight-day case study conducted at the T3-C entrance of Beijing Capital International Airport show that the mean absolute estimation error is 147 s, which is approximately 26.92% of the actual queuing time. For predictions using the NAR model, the proportion is approximately 27.49%. The theoretical predictions and the empirical case study indicate that the NAR model is an effective method to estimate and predict queuing time in indoor public areas.

ACS Style

Hua Shu; Ci Song; Tao Pei; Lianming Xu; Yang Ou; Libin Zhang; Tao Li. Queuing Time Prediction Using WiFi Positioning Data in an Indoor Scenario. Sensors 2016, 16, 1958 .

AMA Style

Hua Shu, Ci Song, Tao Pei, Lianming Xu, Yang Ou, Libin Zhang, Tao Li. Queuing Time Prediction Using WiFi Positioning Data in an Indoor Scenario. Sensors. 2016; 16 (11):1958.

Chicago/Turabian Style

Hua Shu; Ci Song; Tao Pei; Lianming Xu; Yang Ou; Libin Zhang; Tao Li. 2016. "Queuing Time Prediction Using WiFi Positioning Data in an Indoor Scenario." Sensors 16, no. 11: 1958.

Journal article
Published: 01 September 2016 in ISPRS International Journal of Geo-Information
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Many patients prefer to use the best hospitals even if there are one or more other hospitals closer to their homes; this behavior is called “hospital bypass behavior”. Because this behavior can be problematic in urban areas, it is important that it be reduced. In this paper, the taxi GPS data of Beijing and Suzhou were used to measure hospital bypass behavior. The “bypass behavior index” (BBI) represents the bypass behavior for each hospital. The results indicated that the mean hospital bypass trip distance value ranges from 5.988 km to 9.754 km in Beijing and from 4.168 km to 10.283 km in Suzhou. In general, the bypass shares of both areas show a gradually increasing trend. The following hospitals exhibited significant patient bypass behavior: the 301 Hospital, Beijing Children’s Hospital, the Second Affiliated Hospital of Soochow University and the Suzhou Hospital of Traditional Chinese Medicine. The hospitals’ reputation, transport accessibility and spatial distribution were found to be the main factors affecting patient bypass behavior. Although the hospital bypass phenomena generally appeared to be more pronounced in Beijing, the bypass trip distances between hospitals were found to be more significant in Suzhou.

ACS Style

Gege Yang; Ci Song; Hua Shu; Jia Zhang; Tao Pei; Chenghu Zhou. Assessing Patient bypass Behavior Using Taxi Trip Origin–Destination (OD) Data. ISPRS International Journal of Geo-Information 2016, 5, 157 .

AMA Style

Gege Yang, Ci Song, Hua Shu, Jia Zhang, Tao Pei, Chenghu Zhou. Assessing Patient bypass Behavior Using Taxi Trip Origin–Destination (OD) Data. ISPRS International Journal of Geo-Information. 2016; 5 (9):157.

Chicago/Turabian Style

Gege Yang; Ci Song; Hua Shu; Jia Zhang; Tao Pei; Chenghu Zhou. 2016. "Assessing Patient bypass Behavior Using Taxi Trip Origin–Destination (OD) Data." ISPRS International Journal of Geo-Information 5, no. 9: 157.

Journal article
Published: 21 April 2016 in International Journal of Geographical Information Science
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In the high-speed urbanization process of China, the urban population has been increasing significantly, leading to a high-density aggregation of population. However, the sharp increase in population density has not produced commensurate improvements in the road networks. On the contrary, the population increase induced a serious evacuation vulnerability, which cities experience during various hazards and catastrophic events. Therefore, research on evacuation vulnerability is important to urban planning. To assess the evacuation vulnerability, the optimal and worst scenarios should be considered because all possible evacuation plans occur between these extremes. However, most previous evacuation vulnerability studies are based on the worst-case scenario, only providing an upper bound of a potential evacuation assessment. To provide a more comprehensive theoretical basis for decision-makers to understand the consequences caused by all possible evacuations, this paper proposes an optimal evacuation vulnerability assessment model that provides the lower bound on potential evacuation difficulties. The model is solved by a stepwise spreading algorithm based on Graph Theory. Subsequently, to evaluate the effectiveness of the model, the study adopts the model to assess the evacuation capability of different road network topologies. A comparison with previous research was performed. The model was demonstrated in an application to the South Luogu Alley of Beijing, China. The significance of this paper is that the combination of our model with previous research may provide a more complete theoretical basis for an evacuation vulnerability assessment.

ACS Style

Xiaoyi Ma; Tao Pei; Ci Song; Chenghu Zhou. A new assessment model for evacuation vulnerability in urban areas. International Journal of Geographical Information Science 2016, 30, 2401 -2420.

AMA Style

Xiaoyi Ma, Tao Pei, Ci Song, Chenghu Zhou. A new assessment model for evacuation vulnerability in urban areas. International Journal of Geographical Information Science. 2016; 30 (12):2401-2420.

Chicago/Turabian Style

Xiaoyi Ma; Tao Pei; Ci Song; Chenghu Zhou. 2016. "A new assessment model for evacuation vulnerability in urban areas." International Journal of Geographical Information Science 30, no. 12: 2401-2420.

Journal article
Published: 20 April 2015 in Sustainability
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In this study, an inexact stochastic fuzzy programming (ISFP) model is proposed for land-use allocation (LUA) and environmental/ecological planning at a watershed level, where uncertainties associated with land-use parameters, benefit functions, and environmental/ecological requirements are described as discrete intervals, probabilities and fuzzy sets. In this model, an interval stochastic fuzzy programming model is used to support quantitative optimization under uncertainty. Complexities in land-use planning systems can be systematically reflected, thus applicability of the modeling process can be highly enhanced. The proposed method is applied to planning land use/ecological balance in Poyang Lake watershed, China. The objective of the ISFP is maximizing net benefit from the LUA system and the constraints including economic constraints, social constraints, land suitability constraints, environmental constraints, ecological constraints and technical constraints. Modeling results indicate that the desired system benefit will be between [15.17, 18.29] × 1012 yuan under the minimum violating probabilities; the optimized areas of commercial land, industrial land, agricultural land, transportation land, residential land, water land, green land, landfill land and unused land will be optimized cultivated land, forest land, grass land, water land, urban land, unused land and landfill will be [228234, 237844] ha, [47228, 58451] ha, [20982, 23718] ha, [33897, 35280] ha, [15215, 15907] ha, [528, 879] ha and [1023, 1260] ha. These data can be used for generating decision alternatives under different scenarios and thus help decision makers identify desired policies under various system-reliability constraints of ecological requirement and environmental capacity. Tradeoffs between system benefits and constraint-violation risks can be tackled. They are helpful for supporting (a) decision of land-use allocation and government investment; (b) formulation of local policies regarding ecological protection, environment protection and economic development; (c) analysis of interactions among economic benefits, system reliability and ecological requirements.

ACS Style

Bingkui Qiu; Shasha Lu; Min Zhou; Lu Zhang; Yu Deng; Ci Song; Zuo Zhang. A Hybrid Inexact Optimization Method for Land-Use Allocation in Association with Environmental/Ecological Requirements at a Watershed Level. Sustainability 2015, 7, 4643 -4667.

AMA Style

Bingkui Qiu, Shasha Lu, Min Zhou, Lu Zhang, Yu Deng, Ci Song, Zuo Zhang. A Hybrid Inexact Optimization Method for Land-Use Allocation in Association with Environmental/Ecological Requirements at a Watershed Level. Sustainability. 2015; 7 (4):4643-4667.

Chicago/Turabian Style

Bingkui Qiu; Shasha Lu; Min Zhou; Lu Zhang; Yu Deng; Ci Song; Zuo Zhang. 2015. "A Hybrid Inexact Optimization Method for Land-Use Allocation in Association with Environmental/Ecological Requirements at a Watershed Level." Sustainability 7, no. 4: 4643-4667.