The implications of and institutional barriers to compact land development for transportation: Evidence from Bejing

JTLU vol. 6, no. 3, pp. 29-42 (2013)Land use patterns are believed to affect transportation, while low-capacity land-use management is often seen as one of the primary institutional barriers to sustainable transport. Examining the case of Beijing, this paper aims to contribute more evidence in relation to these issues. Over the past decades China’s megacities have witnessed a dramatic transition in land use from traditional compact development to sprawling development due to rapid urbanization. This study found that this transition has tended to increase car usage and thus worsen the emission of pollutants by transport in Beijing when growth of income and other socioeconomic factors are taken into account. It is apparent that compact land-use policies need to be reintroduced to reduce car use. However, there are several institutional barriers related to the reintroduction of compact development in the current context of transition from a centrally planned system to a market system in China’s cities. In particular, increasing fragmentation in the realm of land-development management has created serious challenges to the implementation of compact land-development policies. Therefore, institutional capacity building is needed to enable compact land-use policies to control local sprawl and promote sustainable transport

Uncovering Spatiotemporal Patterns of Travel Flows Under Extreme Weather Events by Tensor Decomposition (Short Paper)

Extreme weather events have caused dramatic damage to human society. Human mobility is one of the important aspects that are impacted significantly by extreme weather. Currently, focus on human mobility research during extreme weather is often limited to the transport infrastructure and emergency management perspectives, lacking a systematic understanding of the spatiotemporal patterns of human travel behavior. In this research, we examine the structural changes in human mobility under the severe rainstorm that occurred on July 20th, 2021 in Zhengzhou, Henan Province, China. Innovatively applying a tensor decomposition approach to analyzing spatiotemporal flows of human movements represented by the mobile phone big data, we extract the characteristic components of human travel behaviors from the spatial and temporal dimensions, which help discover and understand the latent spatiotemporal patterns hidden in human mobility data. This study provides a new methodological perspective and demonstrates that it can be useful for uncovering latent patterns of human mobility and identifying its structural changes during extreme weather events. This is of great importance to a better understanding of the behavioral side of human mobility and its response to external shocks and has significant implications for human-focused policies in urban risk mitigation and emergency response

Quantifying the overall characteristics of urban mobility considering spatial information

Quantification of the overall characteristics of urban mobility using coarse-grained methods is crucial for urban management, planning and sustainable development. Although some recent studies have provided quantification methods for coarse-grained numerical information regarding urban mobility, a method that can simultaneously capture numerical and spatial information remains an outstanding problem. Here, we use mathematical vectors to depict human mobility, with mobility magnitude representing numerical information and mobility direction representing spatial information. We then define anisotropy and centripetality metrics by vector computation to measure imbalance in direction distribution and orientation toward the city center of mobility flows, respectively. As a case study, we apply our method to 60 Chinese cities and identify three mobility patterns: strong monocentric, weak monocentric and polycentric. To better understand mobility pattern, we further study the allometric scaling of the average commuting distance and the spatiotemporal variations of the two metrics in different patterns. Finally, we build a microscopic model to explain the key mechanisms driving the diversity in anisotropy and centripetality. Our work offers a comprehensive method that considers both numerical and spatial information to quantify and classify the overall characteristics of urban mobility, enhancing our understanding of the structure and evolution of urban mobility systems

Genetic structure and insecticide resistance characteristics of fall armyworm populations invading China

The rapid wide‐scale spread of fall armyworm (Spodoptera frugiperda ) has caused serious crop losses globally. However, differences in the genetic background of subpopulations and the mechanisms of rapid adaptation behind the invasion are still not well understood. Here we report the assembly of a 390.38Mb chromosome‐level genome of fall armyworm derived from south‐central Africa using Pacific Bioscience (PacBio) and Hi‐C sequencing technologies, with scaffold N50 of 12.9 Mb and containing 22260 annotated protein‐coding genes. Genome‐wide resequencing of 103 samples and strain identification were conducted to reveal the genetic background of fall armyworm populations in China. Analysis of genes related to pesticide‐ and Bt‐resistance showed that the risk of fall armyworm developing resistance to conventional pesticides is very high. Laboratory bioassay results showed that insects invading China carry resistance to organophosphate and pyrethroid pesticides, but are sensitive to genetically modified maize expressing the Bacillus thuringiensis (Bt) toxin Cry1Ab in field experiments. Additionally, two mitochondrial fragments were found to be inserted into the nuclear genome, with the insertion event occurring after the differentiation of the two strains. This study represents a valuable advance toward improving management strategies for fall armyworm

The split Hopkinson pressure bar for testing concrete and steel fibre reinforced concrete

Develop improvements to the conventional SHPB technique and to apply them to test concrete and steel fibre reinforced concrete (SFRC) materials to obtain reliable stress-strain behaviour under high strain rate loading condition.Doctor of Philosophy (CEE

CENTRIFUGE MODELLING OF SEISMIC AMPLIFICATION IN SOME SINGAPORE SOIL CONDITIONS

Master'sMASTER OF ENGINEERIN

Compact development and metropolitan growth : exploring the impact of urban land development on job accessibility in Beijing

China's urban spatial policy has been stick to the containment development model for the purpose of more sustainable metropolitan growth since the early 1980s. In the model, intensive and compact land use are emphasized to be the primary principle of urban planning and development. This project aims to examine in what way and to what extend the development of urban form correspond to the political guidelines regarding the concept of compact metropolitan growth in the municipality of Beijing, the capital of China. Based on the compact city theory, this research give the empirical case study to examine the compact development policy in Beijing by exploring urban compactness and its consequences at the metropolitan scale (Haidian District), local new town scale (Yizhuang) and street scale (Jiaodaokou Street). GIS mapping and quantitative analysis of the case study areas are used to examine the urban compactness in Beijing. Then the consequences of the compact development is evaluated quantitatively in the perspectives of containyability, accessibility, mobility and livability.

Building knowledge city in transformation era: Knowledge-based urban development in Beijing in the context of globalisation and decentralisation

This study examines knowledge-based urban development in Beijing with the objective of revealing the impact of the 'synergetic' forces of globalisation and local government intervention on knowledge-based urban development in the context of the coexisting processes of globalisation and decentralisation. The findings in this paper show that due to the rapid growth of the cultural industry sector, knowledge-based urban development has created various kinds of 'cultural industry clustered areas', which were recently promoted by the 2008 Olympic Games. 'Synergetic' global and local forces are leading knowledge-based urban development, with the emergence of a local coalition regime in which local government manages local development, considered as 'enterprises' in the decentralisation process, while the State retains a significant influence on knowledge-based urban development. The central and municipal governments tend to emphasise strategies to 'facilitate the climate for growth' rather than the centrally planned control they exerted prior to the 1980s