Xingjian Liu

Global biodiversity research during 1900-2009: a bibliometric analysis

We performed a bibliometric analysis of published biodiversity research for the period of 1900–2009, based on the Science Citation Index (SCI) database. Our analysis reveals the authorial, institutional, spatiotemporal, and categorical patterns in biodiversity research and provides an alternative demonstration of research advancements, which may serve as a potential guide for future research. The growth of article outputs has exploded since the 1990s, along with an increasing collaboration index, references, and citations. Ecology, environmental sciences, biodiversity conservations, and plant science were most frequently used subject categories in biodiversity studies, and Biological Conservation, Journal of Soil and Water Conservation, Conservation Biology and Biodiversity and Conservation were most active journals in this field. The United States was the largest contributor in global biodiversity research, as the U.S. produced the most single-country and collaborative articles, had the greatest number of top research institutions, and had a central position in collaboration networks. We perceived an increasing number of both internationally collaborative and inter-institutionally collaborative articles, with the latter form of collaboration being more prevalent than the former. A keyword analysis found several interesting terminology preferences, confirmed conservation’s central position as a topic in biodiversity research, revealed the adoption of advanced technologies, and demonstrated keen interest in both the patterns and underlying processes of ecosystems. Our study reveals patterns in scientific outputs and academic collaborations and serves as an alternative and innovative way of revealing global research trends in biodiversity.

Automated identification and characterization of parcels with OpenStreetMap and points of interest

Against the paucity of information on urban parcels in China, we propose a method to automatically identify and characterize parcels using OpenStreetMap (OSM) and points of interest (POI) data. Parcels are the basic spatial units for fine-scale urban modeling, urban studies, and spatial planning. Conventional methods for identification and characterization of parcels rely on remote sensing and field surveys, which are labor intensive and resource consuming. Poorly developed digital infrastructure, limited resources, and institutional barriers have all hampered the gathering and application of parcel data in China. Against this backdrop, we employ OSM road networks to identify parcel geometries and POI data to infer parcel characteristics. A vector-based cellular automata model is adopted to select urban parcels. The method is applied to the entire state of China and identifies 82 645 urban parcels in 297 cities. Notwithstanding all the caveats of open and/or crowd-sourced data, our approach can produce a reasonably good approximation of parcels identified using conventional methods, thus it has the potential to become a useful tool.

Global remote sensing research trends during 1991---2010: a bibliometric analysis

According to the articles related to remote sensing of SCI and SSCI databases during 1991–2010, this study evaluated the geographical influence of authors by the new index (geographical impact factor), and revealed the auctorial, institutional, national, and spatiotemporal patterns in remote sensing research. Remote sensing research went up significantly in the past two decades. Imaging science & photographic technology was the important subject category. International Journal of Remote Sensing was the top active journal. All authors were mainly concentrated in North America, Western Europe, and East Asia. Jackson TJ from USDA ARS was the most productive author, Coops NC from University of British Columbia had more high-quality articles, and Running SW from University of Montana carried the greatest geographical influence. The USA was the largest contributor in global remote sensing research with the most single-country and internationally collaborative articles, and the NASA was the most powerful research institute. The international cooperation of remote sensing research increased distinctly. Co-word analysis found the common remote sensing platform and sensors, revealed the widespread adoption of major technologies, and demonstrated keen interest in land cover/land use, vegetation, and climate change. Moreover, the remote sensing research was closely correlated with the satellite development.

Measuring Polycentric Urban Development in China: An Intercity Transportation Network Perspective

Liu X., Derudder B. and Wu K. Measuring polycentric urban development in China: an intercity transportation network perspective, Regional Studies. This paper measures polycentric development in 22 urban regions in China by analysing intercity transportation networks. A typology of Chinese urban regions is identified based on individual regions’ functionally and morphologically polycentricity. Three major sets of processes underlying the typology are discerned: the (mis)match between (governmentally) designated and economically integrated urban regions; unequal interregional economic development; and the impact of city-regional plans and policies. Urban regions along the east coast reach high levels of morphological and functional polycentricity. Many planned urban regions are morphologically polycentric, lacking functional integration. Most urban regions in western China lack any form of polycentricity.

Measurement and interpretation of connectivity of Chinese cities in world city network, 2010

This is an empirical paper that measures and interprets the position of Chinese cities in the world city network in 2010. Building on a specification of the world city network as a ‘interlocking network’ in which business services firms play the crucial role in city network formation, information is gathered about the presence of global service firms in cities. This information is converted into data to provide the ‘service value’ of a city for a firm’s provision of corporate services in a 526 (cities) × 175 (firms) matrix. These data are then used as the input to the interlocking network model in order to measure cities’ connectivity and its predominant geographical orientation. Here we focus on the position of some key Chinese cities in this regard, and discuss and interpret results in the context of the urban dimensions of the ‘opening up’ of the Chinese economy.

China's food security soiled by contamination.

In addition to the rapid reduction of arable land (“Losing arable land, China faces a stark choice: Adapt or go hungry,” C. Larson, News Focus, 8 February, p. [644][1]), soil contamination poses an often overlooked but no less critical threat to Chinas food security. Approximately 8.3% of the

A bibliometric study of earthquake research: 1900-2010

We evaluated earthquake research performance based on a bibliometric analysis of 84,051 documents published in journals and other outlets contained in the Scientific Citation Index (SCI) and Social Science Citation Index (SSCI) bibliographic databases for the period of 1900–2010. We summarized significant publication indicators in earthquake research, evaluated national and institutional research performance, and presented earthquake research development from a supplementary perspective. Research output descriptors suggested a solid development in earthquake research, in terms of increasing scientific production and research collaboration. We identified leading authors, institutions, and nations in earthquake research, and there was an uneven distribution of publications at authorial, institutional, and national levels. The most commonly used keywords appeared in the articles were evolution, California, deformation, model, inversion, seismicity, tectonics, crustal structure, fault, zone, lithosphere, and attenuation.

Mapping producer services networks in mainland Chinese cities

We analyse the geographies of urban networks created by leading producer services (PS) firms in China. Because of the national regulation of the Chinese state-led economy and the location strategies of global advanced producer services (APS) firms, the geography of global APS in China as examined by the Globalization and World Cities Research Network (GaWC) cannot be studied as a subnetwork of GaWC’s global network, but needs an empirical study based on a wide range of leading PS in the Chinese market. We explore the spatial differentiation in the connectivity of Chinese cities based on the location strategies of 323 APS firms in 287 Chinese cities. Beijing, Shanghai, Guangzhou and Shenzhen emerge as the primary nodes. The spatial distribution of banking, securities, and insurance services networks appears to be more even than those of non-financial PS firms. Regional disparity exists in terms of polycentric urban development in coastal China, as well as in the centralisation model in central and western areas. We suggest that owing to the continued tight regulation of China’s state-led economy and the nature of the location strategies of ‘globalised’ PS firms, the urban networks created by Chinese PS firms are not only an extension of urban networks at a global scale but also an embodiment of economic activities at other scales.

Road selection based on Voronoi diagrams and strokes in map generalization

Abstract Road selection is a prerequisite to effective road network generalization. This article introduces a novel algorithm for road network selection in map generalization, which take four types of information into consideration: statistical, metric, topological, and thematic at three spatial scales: macro-scale which describes the general pattern of networks, mezzo-scale that handles relationships among road segments, and micro-scale that focuses on individual roads’ properties. A set of measures is selected to quantify these different types of information at various spatial levels. An algorithm is then developed with the extraction of these measures based on Voronoi diagrams and a perceptual grouping method called “stroke”. The selection process consists of three consecutive steps: measuring network information based on Voronoi partitioning and stroke generation, selecting roads based on information extraction in the first step with strokes as selection unit, and assessing selection results. The algorithm is further tested with a real-world dataset: road network map at 1:10,000 scale and its generalized version at 1:50,000 scale in Wuhan, China. The result reveals that the algorithm can produce reasonable selection results and thus has the potential to be adopted in road selection in map generalization.

Mapping the evolution of hierarchical and regional tendencies in the world city network, 2000-2010

This paper visualizes the evolution of the dominant hierarchical and regional patterns in the world city network, drawing upon an analytical framework integrating categorical correlation, hierarchical clustering, and alluvial diagrams. Our analysis confirms the continued interweaving of hierarchical and regional patterns in the world city network as measured by cities’ similarities in the presence of globalized service firms, but equally highlights some of the key changes that have occurred between 2000 and 2010 such as the rise of the BRIC cities, Dubai’s leading positions in the Arab Gulf, and the stratification of US cities.