Yuanzhi Zhang

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In contrast with the current Web search methods that essentially do document-level ranking and retrieval, we are exploring a new paradigm to enable Web search at the object level. We collect Web information for objects relevant for a specific application domain and rank these objects in terms of their relevance and popularity to answer user queries.(More)
Chromophoric dissolved organic matter (CDOM) is an important optically active substance that transports nutrients, heavy metals, and other pollutants from terrestrial to aquatic systems and is used as a measure of water quality. To investigate how the source and composition of CDOM changes in both space and time, we used chemical, spectroscopic, and(More)
In this paper, the effect of urban heat island is analyzed using the Landsat TM data and ASTER data in 2005 as a case study in Hong Kong. Two algorithms were applied to retrieve the land surface temperature (LST) distribution from the Landsat TM and ASTER data. The spatial pattern of LST in the study area is retrieved to characterize their local effects on(More)
This paper presents the applicability of combined Landsat Thematic Mapper and European Remote Sensing 2 synthetic aperture radar (SAR) data to turbidity, Secchi disk depth, and suspended sediment concentration retrievals in the Gulf of Finland. The results show that the estimated accuracy of these water quality variables using a neural network is much(More)
The objective of this study is to develop techniques for assessing and analysing land desertification in Yulin of Northwest China, as a typical monitoring region through the use of remotely sensed data and geographic information systems (GIS). The methodology included the use of Landsat TM data from 1987, 1996 and 2006, supplemented by aerial photos in(More)
BACKGROUND Chinese injection drug users (IDUs) may be a proper candidate population for HIV vaccine trials. OBJECTIVE To evaluate willingness to participate (WTP) in HIV vaccine trials among Chinese IDUs. METHODS Questionnaire interviews were completed among 401 IDUs in Urumqi City in northwestern China in 2005. RESULTS Overall 74.3% of participants(More)
OBJECTIVE To determine HIV seroincidence, study participant retention rate, and baseline predictors of HIV incidence and study retention among high-risk injection drug users (IDUs) in Xinjiang, China. METHODS A total of 508 eligible seronegative high-risk IDUs were enrolled. Study participants were tested for HIV-1 and counseled at the baseline, 6-month,(More)
OBJECTIVE To determine the demographic characteristics and risk behaviors associated with HIV positive and negative injection drug users (IDUs) who were screened for inclusion in a prospective cohort study to estimate HIV incidence in Xinjiang, China. METHODS Data analyses were performed on the demographic and risk assessment data collected at screening(More)
Water quality monitoring using remote sensing has been studied in Finland for many years. But there are still few discussions on water quality monitoring using remote sensing technology in support of water policy and legislation in Finland under the WFD. In this study, we present water quality monitoring using remote sensing in the Gulf of Finland, and(More)
BACKGROUND Stabilization of rare unstable pelvic fractures in the case of sacral fractures and iliosacral joint dislocations can be tricky. 3D reconstruction and reverse engineering templates may be used to increase the accuracy of screw placement. METHODS Computed tomography (CT) images were used to design the template for 16 consecutive patients with(More)