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CONTEXT Incidence of human immunodeficiency virus (HIV) in the United States has not been directly measured. New assays that differentiate recent vs long-standing HIV infections allow improved estimation of HIV incidence. OBJECTIVE To estimate HIV incidence in the United States. DESIGN, SETTING, AND PATIENTS Remnant diagnostic serum specimens from(More)
1 Visualization of multidimensional data presents special challenges for the design of efficient out-of-core data access. Elements that are nearby in the visualization may not be nearby in the underlying data file, which can severely tax the operating system's disk cache. The Granite Scientific Database System can address these problems because it is aware(More)
High performance computing environments are not freely available to every scientist or programmer. However, massively parallel computational devices are available in nearly every workstation class computer and laptop sold today. The programmable GPU gives immense computational power to a user in a standard office environment; however, programming a GPU to(More)
High performance parallel computing infrastructures, such as computing clusters, have recently become freely available for scientific researchers to solve problems of unprecedented scale through data parallelization. However scientists are not necessarily skilled in writing efficient parallel code, especially when dealing with spatial datasets. Two(More)
Disk and network latency must be taken into account when applying parallel computing to large multidimensional datasets because they can hinder performance by reducing the rate at which data can be fed to the compute nodes. Existing methods aggregate some number of data requests from cluster nodes to improve overall performance by reducing the number of(More)
In this paper we propose a technique called storage-aware spatial prefetching that can provide significant performance improvements for out-of-core visualization. This approach is motivated by file chunking in which a multidimensional data file is reorganized into multidimensional sub-blocks that are stored linearly in the file. This increases the(More)