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Proceedings of the 13th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of database systems

作者： Colby, Latha S. Robertson, Edward L. Saxton, Lawrence V. Van Gucht, Dirk Data parallel Systems Inc

ISBN: (纸本)0897916425

We present a language for querying list-based complex objects. The language is shown to express precisely the polynomial-time generic list-object functions. The iteration mechanism of the language is based on a new approach wherein. in addition to the list over which the iteration is performed, a second list is used to control the number of iteration steps. During the iteration, the intermediate results can be moved to the output list as well as reinserted into the list being iterated over. A simple syntactic constraint allows the growth rate of the intermediate results to be tightly controlled which, in turn, restricts the expressiveness of the language to PTIME.

关键词： Query languages

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THE GPA MACHINE - A GENERALLY PARTITIONABLE MSIMD ARCHITECTURE

THE GPA MACHINE - A GENERALLY PARTITIONABLE MSIMD ARCHITECTU...

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3RD SYMP ON THE FRONTIERS OF MASSIVELY parallel COMPUTATION

作者： BRIDGES, T Data Parallel Systems Inc Bloomington IN USA

ISBN: (纸本)0818620536

The GPA Machine, a massively parallel, multiple single-instruction-stream-multiple-data-stream (MSIMD) system is described. Its distinguishing characteristic is the generality of its partitioning capabilities. Like the PASM system it can be dynamically reconfigured to operate as one or more independent SIMD machines. However, unlike PASM, the only constraint placed on partitioning is that an individual processing element is a member of at most one partition. This capability allows for reconfiguration based on the run-time status of dynamic data structures and for partitioning of disconnected and overlapping data structures. Significant speedups are expected from operating on data structures in place;copying of data to a newly configured partition is unnecessary. The GPA system consists of N processing-element/RAM pairs and an interconnection network providing access to and from P control processors or microcontrollers. With current technologies, values for N and P of 64K and 16, respectively, are feasible.

关键词： MULTIPLE-SIMD MACHINES MSIMD MACHINES SIMD MACHINES parallel PROCESSING PARTITIONABLE RECONFIGURABLE GPA MACHINE

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Query processing for decision support: the SQLmpp solution

Query processing for decision support: the SQLmpp solution

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Proceedings of the 3rd International Conference on parallel and Distributed Information systems

作者： Colby, Latha S. Martin, Nancy L. Wehrmeister, Robert M. Data Parallel Systems Inc Bloomington United States

Decision support systems are characterized by large data sets and complex queries with multi-way joins, aggregation and nesting. SQLmpp is a highly parallel database server designed to efficiently support these applications. SQLmpp's query processing strategy is driven by three principal goals: 1) data parallelism in all operations, 2) maximal use of any relevant indexes, and 3) minimal processing of complete relations. This paper describes the general query processing techniques and the specific operations used to achieve these goals.

关键词： Query languages

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3D pre-stack depth imaging and well ties: A case history of depth imaging in Gulf of Mexico

3D pre-stack depth imaging and well ties: A case history of ...

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2003 Society of Exploration Geophysicists Annual Meeting, SEG 2003

作者： Tadepalli, Sharma Li, Zhiming Su, Chen-Bin BP United States Parallel Data Systems United States

A high-quality 3D pre-stack Kirchhoff depth imaging has significantly improved seismic images over a production field in the Gulf of Mexico. Higher frequency content, relative amplitude preservation, better steep dip accuracy and improved images around and below the salt dome have helped better ties with drilling results in the field. © 2003 SEG Annual Meeting. All rights reserved.

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Kirchhoff or wave equation?

Kirchhoff or wave equation?

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2003 Society of Exploration Geophysicists Annual Meeting, SEG 2003

作者： Li, Zhiming Su, Chen-Bin Bauske, Wes Tadepalli, Sharma Parallel Data Systems United States BP United States

Wave equation (or wave field extrapolation) techniques have been used in industry for the past few years, with the purpose to improve the accuracy of 3D depth imaging over the conventional Kirchhoff migration. However, on many field data examples using different wave equation implementations from different processing shops, we have seen high-quality imaging from both Kirchhoff and wave equation techniques. In the near future, we see that both Kirchhoff and wave equation implementations will continue to serve high fidelity imaging needs and also complement each other in terms of strengths and weaknesses. The benefits of wave equation methods would be significant and overwhelming, perhaps, when we have advanced the acquisition technology to obtain true 3D marine data in the future. © 2003 SEG Annual Meeting. All rights reserved.

关键词： Wave equations

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Depth imaging and regional exploration in Northeast Garden Banks, Gulf of Mexico

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Leading Edge (Tulsa, OK) 2006年第4期25卷 468-473页

作者： Pan, Jeff Barnes, Barbara Kong, Fanchen Chang, Mark Kriechbaum, Victor Li, Zhiming Rodriguez, Gary Zhang, Lin Chang, Itze Su, Chen-Bin Kerr-McGee Houston TX United States Parallel Data Systems Houston TX United States

Since 2002, Kerr-McGee has been using regional (several hundred OCS blocks) 3D prestack depth migrations for exploration in Northeast Garden Banks,located in the deepwater Gulf of Mexico (Figure 1). Advances in prestack depth imaging technology, as well as the experience learned in subsalt imaging in the Gulf of Mexico, have impacted ways we evaluate and explore in the deepwater Gulf of Mexico in the past few years. The regional 3D prestack depth migration provided better understanding of the petroleum systems (salt tectonics, sediment fairways, traps, etc.) and reduced exploration risks.

关键词： Geophysical prospecting

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Improved Pre-stack Depth Images of Pompano Field, Mississippi Canyon, Deepwater Gulf of Mexico 76

Improved Pre-stack Depth Images of Pompano Field, Mississipp...

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Society of Exploration Geophysicists International Exposition and 76tth Annual Meeting 2006, SEG 2006

作者： Chang, Mark Contrino, Charles Li, Zhiming Rodriguez, Gary Zhang, Lin Chang, Itze Su, Chen-Bin Kerr-McGee United States Parallel Data Systems United States

ISBN: (纸本)9781604236972

The deepwater Pompano field is located in Mississippi Canyon in the Gulf of Mexico. Two major salt bodies (Pompano and Lexington) are located in the study area of approximately 27 Outer Continental Shelf blocks (Figure 1). Many passes of pre-stack depth migrations had been applied in the past few years. One of the major challenges is to image the steeply dipping sediment truncations against the base of the salt in the area. The most recent 3D pre-stack depth migration was performed in 2004. Advances in imaging technology (subsalt tomographic velocity inversion, multi-model imaging and detailed salt reinterpretation) showed significant image improvement subsalt for exploration prospects and provided better well-tied seismic images for development well planning. © 1996-2018 Society of Exploration Geophysicists. All rights reserved.

关键词： Image enhancement

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Metrics and Algorithms for Locally Fair and Accurate Classifications using Ensembles

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Datenbank-Spektrum 2022年第1期22卷 23-43页

作者： Lässig, Nico Oppold, Sarah Herschel, Melanie Institute for Parallel and Distributed Systems – Data Engineering University of Stuttgart Universitätsstr. 38 Stuttgart70569 Germany

To obtain accurate predictions of classifiers, model ensembles comprising multiple trained machine learning models are nowadays used. In particular, dynamic model ensembles pick the most accurate model for each query object, by applying the model that performed best on similar data. Dynamic model ensembles may however suffer, similarly to single machine learning models, from bias, which can eventually lead to unfair treatment of certain groups of a general population. To mitigate unfair classification, recent work has thus proposed fair model ensembles, that instead of focusing (solely) on accuracy also optimize global fairness. While such global fairness globally minimizes bias, imbalances may persist in different regions of the data, e.g., caused by some local bias maxima leading to local unfairness. Therefore, we extend our previous work by including a framework that bridges the gap between dynamic model ensembles and fair model ensembles. More precisely, we investigate the problem of devising locally fair and accurate dynamic model ensembles, which ultimately optimize for equal opportunity of similar subjects. We propose a general framework to perform this task and present several algorithms implementing the framework components. In this paper we also present a runtime-efficient framework adaptation that keeps the quality of the results on a similar level. Furthermore, new fairness metrics are presented as well as detailed informations about necessary data preparations. Our evaluation of the framework implementations and metrics shows that our approach outperforms the state-of-the art for different types and degrees of bias present in training data in terms of both local and global fairness, while reaching comparable accuracy. © 2022, The Author(s).

关键词： Dynamic models

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Depth imaging and regional exploration in northeast Garden Banks, Gulf of Mexico 75

Depth imaging and regional exploration in northeast Garden B...

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75th Society of Exploration Geophysicists International Exposition and Annual Meeting, SEG 2005

作者： Pan, Jeff Barnes, Barbara Kong, Fanchen Chang, Mark Kriechbaum, Victor Li, Zhiming Rodriguez, Gary Zhang, Lin Chang, Itze Su, Chen-Bin Kerr-McGee Corporation United States Parallel Data Systems United States

ISBN: (纸本)9781604236101

Since 2002, Kerr-McGee has been using regional (several hundred OCS blocks) 3D pre-stack depth migrations for exploration in Northeast Garden Banks, located in the deepwater Gulf of Mexico (Figure 1). The advances of pre-stack depth imaging technology, as well as the experience and the lessons learned in the subsalt imaging in Gulf of Mexico, has impacted the ways we evaluate and explore in the deepwater Gulf of Mexico in the past few years. The regional 3D pre-stack depth migration provided better understanding of the petroleum systems (salt tectonics, sediment fairways, traps, etc.) and reduced the exploration risks. © Society of Exploration Geophysicists - 75th SEG International Exposition and Annual Meeting, SEG 2005. All rights reserved.

关键词： Subsalt imaging

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Controlled-aperture wave-equation migration

Controlled-aperture wave-equation migration

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2003 Society of Exploration Geophysicists Annual Meeting, SEG 2003

作者： Huang, Lianjie Sun, Hongchuan Fehler, Michael C. Li, Zhiming Los Alamos National Laboratory United States Parallel Data Systems Inc United States

We present a controlled-aperture wave-equation migration method that not only can reduce migration artifacts due to limited recording apertures and determine image weights to balance the effects of limited-aperture illumination, but also can improve the migration accuracy by reducing the slowness perturbations within the controlled migration regions. The method consists of two steps: migration aperture scan and controlled-aperture migration. Migration apertures for a sparse distribution of shots are determined using wave-equation migration, and those for the other shots are obtained by interpolation. During the final controlled-aperture migration step, we can select a reference slowness in controlled regions of the slowness model to reduce slowness perturbations, and consequently increase the accuracy of wave-equation migration methods that make use of reference slownesses. In addition, the computation in the space domain during wavefield downward continuation is needed to be conducted only within the controlled apertures and therefore, the computational cost of the controlled-aperture migration step is less than the corresponding uncontrolled-aperture migration. Finally, we can use the efficient split-step Fourier approach for migration-aperture scan, then use other, more accurate though more expensive, wave-equation migration methods to perform the final controlled-aperture migration to produce the most accurate image. © 2003 SEG Annual Meeting. All rights reserved.

关键词： Image enhancement

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