Browsing by Author "Ferreira, Renato"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Compiler Supported High-level Abstractions for Sparse Disk-Resident Datasets(2001-09-05) Ferreira, Renato; Agrawal, Gagan; Saltz, JoelProcessing and analysing large volumes of data plays an increasingly important role in many domains of scientific research. The complexity and irregularity of datasets in many domains make the task of developing such processing applications tedious and error-prone. We propose use of high-level abstractions for hiding the irregularities in these datasets and enabling rapid development of correct, but not necessarily efficient, data processing applications. We present two execution strategies and a set of compiler analysis techniques for obtaining high performance from applications written using our proposed high-level abstractions. Our execution strategies achieve high locality in disk accesses. Once a disk block is read from the disk, all iterations that read any of the elements from this disk block are performed. To support our execution strategies and improve the performance, we have developed static analysis techniques for: 1) computing the set of iterations that access a particular righ-hand-side element, 2) generating a function that can be applied to the meta-data associated with each disk block, for determining if that disk block needs to be read, and 3) performing code hoisting of conditionals. Cross-referenced as UMIACS-TR-2001-50Item Digital Dynamic Telepathology -- the Virtual Microscope(1998-10-15) Afework, Asmara; Beynon, Michael D.; Bustamante, Fabian; Demarzo, Angelo, M.D.; Ferreira, Renato; Miller, Robert, M.D.; Silberman, Mark, M.D.; Saltz, Joel, M.D., Ph.D.; Sussman, Alan, Ph.D.; Tsang, HubertThe Virtual Microscope is being designed as an integrated computer hardware and software system that generates a highly realistic digital simulation of analog, mechanical light microscopy. We present our work over the past year in meeting the challenges in building such a system. The enhancements we made are discussed, as well as the planned future improvements. Performance results are provided that show that the system scales well, so that many clients can be adequately serviced by an appropriately configured data server. (Also cross-referenced as UMIACS-TR-98-23)Item Performance Evaluation of Client-Server Architectures for Large-Scale Image-Processing Applications(1998-12-16) Beynon, Michael D.; Ferreira, Renato; Afework, Asmara; Mohan, Ganti KrishnaNo abstract available. Also cross-referenced as UMIACS-TR-98-17Item Querying Very Large Multi-dimensional Datasets in ADR - Extended Abstract(1999-05-26) Kurc, Tahsin; Chang, Chialin; Ferreira, Renato; Sussman, Alan; Saltz, JoelThis paper addresses optimizing the execution of range queries into multi-dimensional datasets on distributed memory parallel machines within the Active Data Repository framework. ADR is an infrastructure that integrates storage, retrieval and processing of large multi-dimensional datasets on distributed memory parallel architectures with multiple disks attached to each node. We describe three potential strategies for efficient execution of such queries that employ different tiling and workload partitioning approaches. We evaluate scalability of these strategies for different application scenarios, varying both the number of processors and the input dataset size on a 128 processor IBM SP multicomputer. Also cross-referenced as UMIACS-TR-99-29Item The Virtual Microscope(1998-10-15) Ferreira, Renato; Moon, Bongki; Humphries, Jim; Sussman, Alan; Saltz, Joel; Miller, Robert; Demarzo, AngeloWe present the design of the Virtual Microscope, a software system employing a client/server architecture to provide a realistic emulation of a high power light microscope. We discuss several technical challenges related to providing the performance necessary to achieve rapid response time, mainly in dealing with the enormous amounts of data (tens to hundreds of gigabytes per slide) that must be retrieved from secondary storage and processed. To effectively implement the data server, the system design relies on the computational power and high I/O throughput available from an appropriately configured parallel computer. (Also cross-referenced as UMIACS-TR-97-35)