Qitao Wu

Research on the influence of site factors on the expansion of construction land in the Pearl River Delta, China: By using GIS and remote sensing

Abstract Landsat TM images of the Pearl River Delta taken in 1988, 1998 and 2006 are used to explore the site factors that influence the construction land expansion in this study. Several site factors, including landscape types and the distances to roads, coastlines, or city centers, had significant impacts on the expansion of construction land, influencing the direction, scale and intensity of the expansion. The site factors serve as important natural and spatial indicators of the preferable locales for construction land expansion, describing tendencies to expand to locations in suburbs, plains and areas near roads or coastlines.

Construction of an ecological resistance surface model and its application in urban expansion simulations

Urban expansion models are useful tools to understand urbanization process and have been given much attention. However, urban expansion is a complicated socio-economic phenomenon that is affected by complex and volatile factors involving in great uncertainties. Therefore, the accurate simulation of the urban expansion process remains challenging. In this paper, we make an attempt to solve such uncertainty through a reversal process and view urban expansion as a process wherein the urban landscape overcomes resistance from other landscapes. We developed an innovative approach derived from the minimum cumulative resistance (MCR) model that involved the introduction of a relative resistance factor for different source levels and the consideration of rigid constraints on urban expansion caused by ecological barriers. Using this approach, the urban expansion ecological resistance (UEER) model was created to describe ecological resistance surfaces suitable for simulating urban expansion and used to simulate urban expansion in Guangzhou. The study results demonstrate that the ecological resistance surface generated by the UEER model comprehensively reflects ecological resistance to urban expansion and indicates the spatial trends in urban expansion. The simulation results from the UEER-based model were more realistic and more accurately reflected ecological protection requirements than the conventional MCR-based model. These findings can enhance urban expansion simulation methods.

Optimal Hub Port Locations in China-Western Europe Container Liner Route

The hub-and-spoke network has been applied in the maritime transport since 1980s. To realize the economy of scale, transoceanic containerships optimize their liner routes to call only a limited number of hub ports. This paper develops a non-Symmetrical Proportional Model to calculate the origin-destination (O-D) container matrix of the port system. Then a Hub-and-Spoke Maritime Container Transport model is applied in the China-Western Europe liner route, which is under the rapid expansion of container shipping, to determine the hub ports that the liners stop and call. To solve real-sized instances, the heuristic algorithm is proposed and the solution is optimized by comparing the alternative results from the model computation. For the hub location, Hamburg, Rotterdam, Zeebrugge, Hong Kong, Kaohsiung and Shanghai are the optimal hubs in the China-Western European container liners route. At last, further research direction is predicted to simulate under the real scenario.