Large Cities In China Research Articles

Integrating the Eigendecomposition Approach and k-Means Clustering for Inferring Building Functions with Location-Based Social Media Data

Understanding the relationship between human activity patterns and urban spatial structure planning is one of the core research topics in urban planning. Since a building is the basic spatial unit of the urban spatial structure, identifying building function types, according to human activities, is essential but challenging. This study presented a novel approach that integrated the eigendecomposition method and k-means clustering for inferring building function types according to location-based social media data, Tencent User Density (TUD) data. The eigendecomposition approach was used to extract the effective principal components (PCs) to characterize the temporal patterns of human activities at building level. This was combined with k-means clustering for building function identification. The proposed method was applied to the study area of Tianhe district, Guangzhou, one of the largest cities in China. The building inference results were verified through the random sampling of AOI data and street views in Baidu Maps. The accuracy for all building clusters exceeded 83.00%. The results indicated that the eigendecomposition approach is effective for revealing the temporal structure inherent in human activities, and the proposed eigendecomposition-k-means clustering approach is reliable for building function identification based on social media data.

To comply or not to comply? Migrants’ responses to educational barriers in large cities in China

ABSTRACT Migrant children in Chinese cities face educational barriers due to the lack of a local household registration (hukou). Based on in-depth interviews with migrant families conducted between 2015–19 in Shanghai, and court judgments of the administrative litigations on migrant children’s education covering 13 large cities released by the Supreme People’s Court of the People’s Republic of China, this Research Note examines migrants’ responses to educational barriers and the consequential educational trajectories in large cities in China. Specifically, we identify and analyze nine responses in two categories: compliance, including policy followers, vocational school attendees, returnees, and remigrating children; and noncompliance, including policy benders, policy by-passers, dropouts, petitioners, and lawsuit filers. Every response contains various actions, incurs different costs, and achieves different educational outcomes. We also discuss how the educational barriers exert pressure upon certain migrants to engage in noncomplying rather than complying conduct.

Distribution and Influencing Factors of DOM Components in Urban and Suburban Polluted Rivers

Dissolved organic matter(DOM) in water environments is an important component of the global carbon cycle. Under the current urgency to control the pollution of urban rivers in China, exploring the influence of different exogenous and endogenous secondary pollution and weather patterns on river DOM is the premise to better understand the causes of the pollution. In this study, a large city in China was established as the research area, and the underlying water and sediments from 21 sites along urban and suburban rivers, and other water sources were evaluated. The excitation-emission matrix-parallel factor analysis(EEM-PARAFAC) was used to analyze the difference in DOM composition and equivalent in urban rivers polluted by domestic sewage and suburban rivers polluted by aquaculture, agriculture, and livestock breeding. The results showed that:① DOM components in urban and suburban river waters were mainly protein compounds(tyrosine-and tryptophan-like), containing a small amount of humic acid. Humic acid components of anthropogenic origin were found in urban river water; ② The reasons for the formation of DOM components in urban and suburban rivers were completely different. Urban rivers are mainly polluted by domestic sewage and endogenous secondary pollution, resulting in an increase in anthropogenic humic acid components. Suburban rivers are mainly polluted by agricultural wastewater rich in N and P, which promotes endogenous metabolism of autotrophic bacteria and increases protein components, which may be related to the formation of existing DOM characteristics. ③ Rainfall runoff and urban overflow transported exogenous pollutants into rivers, while hydrodynamic factors such as hydraulic agitation affect the distribution of DOM components in underlying water and sediments through physical effects such as dilution.

Evaluation of China's low-carbon city pilot policy: Evidence from 210 prefecture-level cities.

As the largest carbon dioxide emitter, China is working towards the direction of a green economy. As an irreplaceable part of establishing a green economy, the low-carbon city pilot (LCCP) policy is implemented in many large cities in China, and the scope of implementation will be further expanded. However, to date, there has been an absence of empirical studies basing on prefecture-level cities about the evaluation of China’s LCCP policy. Evaluating and optimizing the LCCP policy is constructive to achieve the goal of China’s green economic transition. In this paper, we evaluated the effect of the LCCP policy on China’s low-carbon economic transition by using the difference-in-difference (DID) approach which can effectively alleviate endogenous problems and better evaluate this effect and the panel data of 210 prefecture-level cities in China from 2008 to 2016. The empirical analysis revealed that the LCCP policy inhibited China’s low-carbon economic transition in general. Specifically, the policy worked well in the eastern region but failed in the central region and western region by studying the regional heterogeneity and influence mechanism. The reason is that the LCCP policy can stimulate low-carbon innovation with the help of innovation offset effects in the eastern region, but it failed to do so in the central region and western region. In addition, this paper analyzed the performance of three types of policy tools adopted by local governments to implement the policy, we found that market-economic tools are valuable to improving the low-carbon economic transition in pilot areas, but command-mandatory tools and voluntary tools have failed to achieve the expected objectives. The research results of this article can provide policy recommendations for optimizing the low-carbon policy and provide a reference for countries that are determined to develop a green economy.

Tradable parking permits as a transportation demand management strategy: A behavioural investigation

Tradable parking permit schemes can be an effective transportation demand management strategy for cities where cars are viewed as a status symbol and wide adoption of shared transportation modes face resistance. We investigate the feasibility and effectiveness of tradable parking permit schemes in high density cities with parking constraints. We focus on the effect of four behavioural factors, namely, reference dependence, endowment effect, social nudge, and environmental consciousness. Online experiments are conducted via Amazon Turk Prime platform, with participants recruited from large cities in China. Our investigation on reference dependence and endowment effect suggest that tradable parking permit schemes is feasible and efficient. Environmental consciousness can improve the schemes' effectiveness in encouraging participants to switch to public transport, but social nudge shows no significant effect. Our study provides much-needed empirical findings about tradable credits for transportation management on the individual level.

Mathematical Models and Data Analysis of Residential Land Leasing Behavior of District Governments of Beijing in China

To analyze the leasing behavior of residential land in Beijing, the mathematical models of the price and the total area of the leased residential land are presented. The variables of the mathematical models are proposed by analyzing the factors influencing the district government’s leasing behavior for residential land based on the leasing right for residential land in Beijing, China. The regression formulae of the mathematical models are obtained with the ordinary least squares method. By introducing the data of the districts in Beijing from 2004 to 2015 into the mathematical models, the numerical results of the coefficients in the mathematical models are obtained by solving the equations of the regression formulae. After discussing the numerical results of the influencing factors, the district government behavior for leasing residential land in Beijing, China, is investigated. The numerical results show the factors concerning the government and how these factors influence the leased price and the total leased area of residential land for this large city in China. Finally, policy implications for the district government regarding residential land leasing in Beijing are proposed.

Spatio-temporal changes in urban green space in 107 Chinese cities (1990–2019): The role of economic drivers and policy

Urban green space (UGS) has gained increasing attention due to its environmental and social functions. However, the compound effects of climate change, population growth and economic development on UGS are largely unknown. We selected 107 medium-sized and large cities in China to investigate dynamics in the spatial pattern of UGS in relation to government policy and other drivers based on remote sensing data for the period 1990 to 2019. To explore the effect of different levels of urbanization on changes in green space, we develop a new Normalized Urban Development Index (NUDI) to classify urban-suburban-rural gradients, viz. Long-term Built-up, New Built-up and Non-Built-up. Then, we analysed changes over time in the annual peak value of fraction of vegetation cover (FVC) for 380,000 cloud-free Landsat images, and regional UGS dynamics were evaluated using the proposed Regional Greenness Dynamic Index (RGDI). Finally, to reveal the major driver(s) of changes in UGS and estimate the extent to which patterns of urban greening are due to differences in economic development, we compared the observed UGS spatio-temporal dynamics with data on several climatic, social-economic and land use related factors for the same period. The NUDI are shown to be highly effective in mapping urban development gradients, with overall accuracy in the identified classes of 89%. Annual maximum FVC analysis indicates that there was significant greening between 1990 and 2019 in both the long-term built up (10,667.52 km2) and the non-built up areas (529,310.47 km2), while there was a major increase in browning (25,110.43 km2) in the newly built-up areas. The RGDI results indicate that 65% (71/107) of long-term built-up areas in cities trended greener over 2010 to 2019 under consideration. At the whole city scale, RGDI is negatively correlated with gross domestic product (GDP), although when considering the long-term built-up areas only, economic growth exhibits a significant positive correlation during 2010 to 2019 (R = 0.62, p < 0.01). This study offers important insights as to the patterns of change in urban greening extent over time and its underyling drivers across urban-suburban-rural gradients against the background of urban expansion, afforestation, climate change and economic development.

Disparities of birth cohort effects on pancreatic cancer incidence between the United States and urban China

BackgroundPancreatic cancer has been associated with lifestyle factors, but few comparative studies were conducted among countries of different culture and lifestyle habits. This study compared the trends of pancreatic cancer incidence and birth cohort effects in the United States and urban China and explored the potential discrepancies of risk patterns.Materials and methodsAge-standardized incidence rates (ASIRs) were calculated using data from national or regional cancer registries of the United States and two large cities of China (Shanghai, Hong Kong). The temporal trends of incidence were assessed by joinpoint regression. The effects of birth cohort and calendar period were identified through age–period–cohort modeling.ResultsThe ASIR in the United States from 1976 to 2015 was 8.26/100 000, which was higher than that in Hong Kong (4.29/100 000) and Shanghai of China (6.63/100 000). Shanghai had lower incidence (4.41/100 000) in 1976-1980 but increased annually by 1.38% in males and 1.67% in females, with a sharper upward trend than the United States and Hong Kong. Males had higher risks than females, with a male-to-female ratio of 1.34, 1.44, and 1.37 in the United States, Hong Kong, and Shanghai, respectively. A significant and prominent increase in incidence rate was observed among successive generations in China particularly for Shanghai, but such a pattern was not apparent in the United States.ConclusionsThe differences in pancreatic cancer incidence by sex may be multi-factorial involving known risk factors like tobacco smoking and alcohol consumption. The significant birth cohort effects among recent and early generations in the Shanghai population were in line with a society in socioeconomic transition and adoption of Western lifestyle mainly including consumption of calorie-rich foods and physical inactivity. Differences in these risk patterns will have implications on health care efforts and policies for cancer control.

Validation of the Internet Gaming Disorder Symptoms Checklist Based on the Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders in Chinese Adolescents.

This study aims to develop and validate a checklist for IGD symptoms of Chinese adolescents based on the fifth edition of the diagnostic and statistical manual of mental disorders (DISCA). We recruited 2144 secondary school students who reported that they had played Internet games in the past 12months in two large cities of China. The 9 item of DISCA were all significantly and positively correlated and the scale reliability was satisfactory. The unidimensional structure of the scale was confirmed by Confirmatory Factor Analysis (CFA), χ2/df = 246.18/27, CFI = .95, RMSEA = .06. Measurement invariance across gender and city groups was confirmed by Multiple-group CFA. Criterion validity was demonstrated by the significant positive associations between DISCA score and self-identified IGD, loss of control regarding time spent on Internet gaming, time spent on playing Internet games, depression, and suicidal ideation. DISCA is a brief, reliable, and validated assessment to measure adolescent IGD.

A generalized fluid model of ride-hailing systems

This paper proposes a macroscopic fluid modeling framework to assist with strategic decision making of a platform for operating a large-scale on-demand app-based ride-hailing system. The framework captures the spatiotemporal characteristics of a ride-hailing system, and is flexible in representing control policies that a platform is implementing. It thus enables the analysis of a large-scale ride-hailing system with observable market responses and facilitates the optimization of the control polices. As a demonstration of the proposed framework, we customize it for a ride-hailing system operated by Didi Chuxing in a large city of China, and conduct an empirical study of the system. In doing so, we calibrate the model with a high degree of granularity using empirical data, and then investigate optimal pricing strategies to achieve various managerial objectives of the platform. To our best knowledge, the proposed model is the first of its kind that offers a tractable way to support the analysis and optimization of large-scale ride-hailing systems. The empirical study also provides one of the first testbeds for examining various operations strategies for ride-hailing services.

Spaces of Suspension: Construction, Demolition, and Extension in a Beijing Migrant Neighbourhood

Communities with large concentrations of migrants, who often live in makeshift and illegal housing, have been common on the margins of large cities in China since the 1980s. Why do so-called "urban villages" persist and even flourish despite repeated government crackdowns? By addressing this question, this article sheds light on a subtle dynamic of city making that has not been fully appreciated by scholarly literature and media reports that have focused on large-scale demolition and eviction in China's rapid urbanization. Drawing from my two years of field research in Hua village, a community on Beijing's fringes in line for land expropriation, I explore how multilateral negotiations between local residents (villagers), migrant tenants, the village committee, and municipal government led to a cyclical movement of temporary housing construction, demolition, and extension. The dynamics of recurring demolishment and reconstruction engendered spaces of suspension, which enabled migrants to enter the urban economy at a low cost. Such spaces, however, offered no formal protection or basis for developing lasting social relations, and always faced the prospect of being demolished, but nevertheless were constantly available and even expanding.

Live poultry feeding and trading network and the transmission of avian influenza A(H5N6) virus in a large city in China, 2014–2015

ObjectivesTo understand the transmission mechanisms of the avian influenza A(H5N6) virus. MethodsThis study explored the live poultry feeding and trading network (LPFTN) around Changsha city, China. Field epidemiological investigations were performed in Changsha to investigate the LPFTN with the environmental samples systematically collected during 2014–2015 to monitor and analyze the spread of the A(H5N6) virus. Two surveillance systems were also applied to find possible human cases of A(H5N6) infection. ResultThe information of all the 665 live poultry farming sites, five wholesale markets, and 223 retail markets in Changsha was collected to investigate the LPFTN. Moreover, about 840 environmental samples were systematically collected from the LPFTN during 2014–2015 to monitor the spread of the A(H5N6) virus, with 8.45% (71/840) positive for the N6 subtype. Furthermore, the full genome sequences of 10 A(H5N6) viruses detected from the environmental samples were obtained, which were then characterized and phylogenetically analyzed with the corresponding gene segments of the A(H5N6) virus obtained from GenBank, to determine the source of human infection. ConclusionIt was demonstrated that the LPFTN provided a platform for the H5N6 transmission, and formed an infectious pool for the spread of the virus to humans.

Impacts of high-speed rail development on urban land expansion and utilization intensity in China

Urban land expansion (ULE) is a crucial factor for socioeconomic and environmentally sustainable development. However, nowadays, the unprecedented scale of high-speed railway (HSR) construction in China could exert an important influence on ULE. This manuscript first reveals the influence mechanism of HSR on ULE and then employs difference-in-difference (DID) models to investigate this effect based on the data of 280 prefectures and above level cities of 2001-2016. We analyze that HSR exerts a joint effect on ULE from the territorial and local levels and then affects urban land-use intensity (ULUI). HSR opening and HSR station distance both have notably positive effects on ULE, with elastic coefficients of 4.1% and 0.5%, respectively. HSR opening and HSR station distance also both exert positive effects on ULE of the central, eastern region cities and large cities of China, while for the western region and small to medium cities, they are not significant. The impact of HSR station distance on ULUI is negative with a significance level of 0.073, while the impact of HSR opening on ULUI is not significant. Lastly, relevant policy implications are proposed to alleviate urban land waste and spatial disequilibrium under the context of HSR building. This study can provide an important basis for sustainable urban land allocation.

Covid-19, capitalism and political elites: The real threat to humanity

It has been more than a year since the Covid-19 outbreak in Wuhan, one of the largest cities in China. The global tsunami that followed took the bourgeois regimes across the globe by surprise heralding a new era of socioeconomic misery, suggesting that this multifaceted crisis could become the worst crisis in the history of capitalism. The inability of the current political system to deal with the Covid-19 pandemic became apparent from the very outset, hence exposing – in the most emphatic manner – the ills of the dominant market economy. In this opinion paper, we argue that society, as a global collective entity, has been reduced to an entity that obeys orders and dances to the rhythm set by international organizations. Furthermore, the severely restricted political and social rights might be a dress rehearsal of what the future holds for humanity.

An Effect Of Management Service Quality On Residential Satisfaction And Recommended Intention Of High-Rise Apartments

Recently, a lot of high-rise apartments are being built around large cities in the world. The high-rise apartments are a valuable living space for residents and are located in the center of the city, providing a distinctive and advanced residents' convenience while maintaining a high price of real estate along with the landmark role. In this background this study examined the relationship between the evaluation of the quality of management services perceived by residents and the satisfaction and recommendation intention of tenants living in high-rise apartments in China. This study empirically examines the relationship between the quality of management services (environmental quality, process quality, result quality), satisfaction and recommendation intention of tenants living in ‘high-rise apartments’ in large cities in China. The results showed that the quality of management services of high-rise apartments had a significant effect on residential satisfaction and recommended intention. In addition, among the quality of management service affecting residential satisfaction and recommendation intention, the relationship was the highest in the order of process quality (β=.363, t=5.362), result quality (β=.306, t=5.610), and environmental quality (β=.200, t=3.319). Therefore, in order to enhance the satisfaction of the residents of high-rise apartments and to induce positive attitudes and follow-up actions, it is necessary to pay attention to the needs of the residents and deal with them promptly and kindly, rather than the physical environmental quality of the high-rise apartments and the quality improvement efforts shown in the research results. Therefore, in order to enhance the satisfaction of the residents of high-rise apartments and to induce positive attitudes and follow-up actions, it is necessary to pay attention to the needs of the residents and deal with them promptly and kindly, rather than the physical environmental quality of the high-rise apartments and the quality improvement efforts shown in the research results. It can be said to be an important implication confirmed through this study.

Occurrence of antibiotics and antibiotic resistance genes and their correlations in river-type drinking water source, China.

The occurrence and distribution of antibiotics and antibiotic resistance genes (ARGs) in natural water has attracted worldwide attention. Antibiotic and ARG pollution in the surface water of drinking water sources might directly/indirectly affect human health. In this study, the distribution of 38 antibiotics, 10 ARGs, 2 integrons, and 16S r DNA in river-type water sources in a large city of China were monitored in winter, which was a period with high level of antibiotic pollution. The results showed that 20 antibiotics were detected with different detection frequencies. The antibiotic pollution in December 2019 was relatively high, with the total concentrations of antibiotics ranging from 281.95 to 472.42 ng/L, followed by that in January 2020 (191.70-337.29 ng/L) and November 2019 (161.25-309.72 ng/L). Sulfacetamide was dominant in November 2019 (23.52-219.00 ng/L) and in January 2020 (113.18-209 ng/L), while norfloxacin in December 2019 (146.72-290.20 ng/L). All the target antibiotics posed low or medium risk for aquatic organisms, and posed low health risk for mankind. Sul1 and erm36 were the predominant ARGs, and intI1 was the predominant integron in drinking water sources. Only tetA showed positive correlations with its corresponding antibiotic (tetracycline). The rest of ARGs showed no correlations with antibiotics or positive / negative correlations with their non-corresponding antibiotics. Overall, the antibiotics and ARG pollution in these water sources was relatively low. These findings provided some reference data for the distribution of antibiotics and ARGs in river-type drinking water sources of large cities in China.

Exploring influencing factors on metro development in China from urban and economic perspectives

As an important form of public transport and utilisation of urban underground space (UUS), metro has been promoted in an increasing number of large cities in China. By the end of 2019, China’s 37 cities had developed metro systems with a total length of over 5000 km. It is widely acknowledged that urban and economic factors can significantly influence transport infrastructure development and UUS utilisation. The results of this study indicate that there are statistically significant relationships between urban and economic factors and the level of metro development. The results of the regression analyses show that the variables of metro operation history and general public budget revenue are significantly and positively related to metro operation length, number of lines and number of stations of cities with metros in China. Resident population in urban areas does not appear to be a significant determinant of the level of metro development when other urban economic factors are controlled for. Administrative division (prefecture-level cities) and economic regions (Northeast Region) are significantly and negatively associated with the level of metro development in China. The findings of this study suggest that policy and institutional factors, and operation history of metro, along with urban and economic factors such as economic capabilities, regional differentiation, and administrative divisions, play important roles in influencing the development levels of metro systems in China.

Analysis of Long-term Care Insurance Demand of Megalopolis in China under the Background of Aging of Population—Take Shanghai as an Example

The development of Long-term Care Insurance (LTCI), which matches that people get old before becoming rich lag behind. The mega-urban agglomeration formed in the metropolitan area under the process of urbanization intensifies the demand for insurance driven by long-term care needs. This paper constructs a theoretical model to sort out the micro-action mechanism of LTCI products entering the production field through the consumption of corporate security services, and at the same time entering the consumption field in the form of security services demand from families, individuals and government agencies, it reveals that the differences in the micro-paths of LTCI products entering the enterprise production field and the household consumption field under different regional economic and social conditions. Then, using the GM (1,1) model to analyze the demand for LTCI under the aging population trend of Shanghai, a super large city in China, we found that the situation and characteristics of Shanghai and Japan are similar, and the number of people who need care under the distribution of the elderly population in Shanghai from 2017 to 2027 is much lower than the number of people who need LTCI. Meanwhile, the current long-term nursing service has a large labor gap and high professional skills requirements, but the current salary is low. Besides, the share of elderly care institutions is small, which is not enough to support the current occupancy needs of severely disabled people. The actual development has a greater potential impact on public health expenditures, especially the increase in public health expenditures after the outbreak of the COVID-19 has brought uncertainty. Based on the above findings, we propose to introduce the successful mode of American political and commercial cooperation and the Japanese social security model to alleviate the rapid growth in the demand for LTCI accompanied by the aging trend in the mega-urban clusters formed in the urbanization process.

Performance Evaluation of Public Bus Transportation by Using DEA Models and Shannon's Entropy: An Example From a Company in a Large City of China

The purpose of this paper is to assess the operational efficiency of a public bus transportation via a case study from a company in a large city of China by using data envelopment analysis (DEA) model and Shannon's entropy. This company operates 37 main routes on the backbone roads. Thus, it plays a significant role in public transportation in the city. According to bus industry norms, an efficiency evaluation index system is constructed from the perspective of both company operations and passenger demands. For passenger satisfaction, passenger waiting time and passenger-crowding degree are considered, and they are undesirable indicators. To describe such indicators, a superefficient DEA model is constructed. With this model, by using actual data, efficiency is evaluated for each bus route. Results show that the DEA model with Shannon's entropy being combined achieves more reasonable results. Also, sensitivity analysis is presented. Therefore, the results are meaningful for the company to improve its operations and management.

Moving towards a sustainable and innovative city: Internal urban traffic accessibility and high-level innovation based on platform monitoring data

Quantitative evaluation of the impact of traffic accessibility within large cities on innovation quality is conducive to a better understanding of urban governance and sustainable development. This paper analyzed the impact of traffic accessibility on regional and enterprise innovation using the big data from a floating car track monitored by the platform in five large cities in China. The study found that there is significant heterogeneity in the quantity, structure, and spatial distribution characteristics of high-level innovation. For every 1% increase in the speed of traffic in townships and blocks, the number of invention patent applications in Type-I cities with a population between three and five million will increase by 4.175%, and the positive impact on low-tech patent applications will be clearer. With improved traffic accessibility, the high-level innovation in super-large cities and Type-I cities tends to focus on spatial diffusion. Evidence from the multiscale geographically weighted regression (MGWR) shows that even within the same type of city, the sensitivity of high-level innovation of enterprises in different spatial locations to traffic speed is significantly heterogeneous. This suggests that future infrastructure construction and traffic system optimization should focus on more sensitive enterprise clusters.