Hongjun Zhu

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Spatial joins are very important but costly operations in spatial databases. A typical evaluation strategy of spatial joins is to perform the join on approximations of spatial objects and then evaluate the join of the real objects based on the results. The common approximation is the minimum bounding rectangle. Minimum bounding rectangles are coarse(More)
An important class of queries in moving object databases involves trajectories. We propose to divide trajectory predicates into topological and non-topological parts; extend the 9 intersection model of Egenhofer-Franzosa to a 3-step evaluation strategy for trajectory queries: a filter step, a refinement step, and a tracing step.The filter and refinement(More)
A two-dimensional, transient, finite-element model has been developed to simulate temperature, shape, and stress development in the steel shell, during the initial stages of solidification in the mold. The model is applied to predict the distorted shape of a vertical section through the shell, during a sudden fluctuation in liquid level at the meniscus. The(More)
Spatial joins are fundamental in spatial databases. Over the last decade, the primary focus of research has been on joins with the predicate " region intersection. " In modern database applications involving geospatial data such as GIS, efficient evaluation of joins with other spatial predicates is yet to be fully explored. In addition, most existing join(More)
Keywords: Crude oil Double pipelines Temperature field Thermal influential factor Numerical simulation Computational fluid dynamics (CFD) Ambient temperature a b s t r a c t Crude oil pipeline laid with products pipeline in the same ditch is a new technology to save investment and protect environment. In order to provide reference to construction and(More)
BACKGROUND Increasing evidence indicates that the rapid component of delayed rectifier potassium current (I(Kr)) is modulated by α- and β-adrenergic stimulation. However, the role and mechanism regulating I(Kr) through β(2)-adrenoreceptor (β-AR) stimulation in heart failure (HF) are unclear. METHODOLOGY/PRINCIPAL FINDINGS In the present study, we(More)