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1

A Parallel Search Algorithm for Directed Acyclic Graphs  

Microsoft Academic Search

A parallel algorithm for depth-first searching of a directed acyclic graph (DAG) on a shared memory model of a SIMD computer is proposed. The algorithm uses two parallel tree traversal algorithms, one for the preorder traversal and the other for therpostorder traversal of an ordered tree. Each of these traversal algorithms has a time complexity ofO(logn) whenO(n) processors are used,n

Ratan K. Ghosh; G. P. Bhattacharjee

1984-01-01

2

Parallel text search methods  

Microsoft Academic Search

A comparison of recently proposed parallel text search methods to alternative available search strategies that use serial processing machines suggests parallel methods do not provide large-scale gains in either retrieval effectiveness or efficiency.

Gerard Salton; Chris Buckley

1988-01-01

3

Parallel controlled conspiracy number search  

Microsoft Academic Search

Tree search algorithms play an important role in many applications in the field of artificial intelligence. When playing board games like chess etc., computers use game tree search algorithms to evaluate a position. In this paper, we present a procedure that we call Parallel Controlled Conspiracy Number Search (Parallel CCNS). Shortly, we describe the principles of the sequential CCNS algorithm,

Ulf Lorenz

2001-01-01

4

Randomized Parallel Proof-Number Search  

NASA Astrophysics Data System (ADS)

Proof-Number Search (PNS) is a powerful method for solving games and game positions. Over the years, the research on PNS has steadily produced new insights and techniques. With multi-core processors becoming established in the recent past, the question of parallelizing PNS has gained new urgency. This article presents a new technique called Randomized Parallel Proof-Number Search (RPPNS) for parallelizing PNS on multi-core systems with shared memory. The parallelization is based on randomizing the move selection of multiple threads, which operate on the same search tree. RPPNS is tested on a set of complex Lines-of-Action endgame positions. Experiments show that RPPNS scales well. Four directions for future research are given.

Saito, Jahn-Takeshi; Winands, Mark H. M.; van den Herik, H. Jaap

5

Parallel Processing in Visual Search Asymmetry  

ERIC Educational Resources Information Center

The difficulty of visual search may depend on assignment of the same visual elements as targets and distractors-search asymmetry. Easy C-in-O searches and difficult O-in-C searches are often associated with parallel and serial search, respectively. Here, the time course of visual search was measured for both tasks with speed-accuracy methods. The…

Dosher, Barbara Anne; Han, Songmei; Lu, Zhong-Lin

2004-01-01

6

Efficiency of parallel direct optimization  

NASA Technical Reports Server (NTRS)

Tremendous progress has been made at the level of sequential computation in phylogenetics. However, little attention has been paid to parallel computation. Parallel computing is particularly suited to phylogenetics because of the many ways large computational problems can be broken into parts that can be analyzed concurrently. In this paper, we investigate the scaling factors and efficiency of random addition and tree refinement strategies using the direct optimization software, POY, on a small (10 slave processors) and a large (256 slave processors) cluster of networked PCs running LINUX. These algorithms were tested on several data sets composed of DNA and morphology ranging from 40 to 500 taxa. Various algorithms in POY show fundamentally different properties within and between clusters. All algorithms are efficient on the small cluster for the 40-taxon data set. On the large cluster, multibuilding exhibits excellent parallel efficiency, whereas parallel building is inefficient. These results are independent of data set size. Branch swapping in parallel shows excellent speed-up for 16 slave processors on the large cluster. However, there is no appreciable speed-up for branch swapping with the further addition of slave processors (>16). This result is independent of data set size. Ratcheting in parallel is efficient with the addition of up to 32 processors in the large cluster. This result is independent of data set size. c2001 The Willi Hennig Society.

Janies, D. A.; Wheeler, W. C.

2001-01-01

7

Asynchronous parallel pattern search for nonlinear optimization  

SciTech Connect

Parallel pattern search (PPS) can be quite useful for engineering optimization problems characterized by a small number of variables (say 10--50) and by expensive objective function evaluations such as complex simulations that take from minutes to hours to run. However, PPS, which was originally designed for execution on homogeneous and tightly-coupled parallel machine, is not well suited to the more heterogeneous, loosely-coupled, and even fault-prone parallel systems available today. Specifically, PPS is hindered by synchronization penalties and cannot recover in the event of a failure. The authors introduce a new asynchronous and fault tolerant parallel pattern search (AAPS) method and demonstrate its effectiveness on both simple test problems as well as some engineering optimization problems

P. D. Hough; T. G. Kolda; V. J. Torczon

2000-01-01

8

HOPSPACK: Hybrid Optimization Parallel Search Package.  

SciTech Connect

In this paper, we describe the technical details of HOPSPACK (Hybrid Optimization Parallel SearchPackage), a new software platform which facilitates combining multiple optimization routines into asingle, tightly-coupled, hybrid algorithm that supports parallel function evaluations. The frameworkis designed such that existing optimization source code can be easily incorporated with minimalcode modification. By maintaining the integrity of each individual solver, the strengths and codesophistication of the original optimization package are retained and exploited.4

Gray, Genetha A.; Kolda, Tamara G.; Griffin, Joshua; Taddy, Matt; Martinez-Canales, Monica

2008-12-01

9

Quantum search by parallel eigenvalue adiabatic passage  

NASA Astrophysics Data System (ADS)

We propose a strategy to implement the Grover search algorithm by adiabatic passage in a very efficient way. An adiabatic process can be characterized by the instantaneous eigenvalues of the pertaining Hamiltonian, some of which form a gap. The key to the efficiency is based on the use of parallel eigenvalues. This allows us to obtain nonadiabatic losses that are exponentially small, independently of the number of items in the database in which the search is performed.

Daems, D.; Guérin, S.; Cerf, N. J.

2008-10-01

10

Parallel search of strongly ordered game trees  

SciTech Connect

The alpha-beta algorithm forms the basis of many programs that search game trees. A number of methods have been designed to improve the utility of the sequential version of this algorithm, especially for use in game-playing programs. These enhancements are based on the observation that alpha beta is most effective when the best move in each position is considered early in the search. Trees that have this so-called strong ordering property are not only of practical importance but possess characteristics that can be exploited in both sequential and parallel environments. This paper draws upon experiences gained during the development of programs which search chess game trees. Over the past decade major enhancements of the alpha beta algorithm have been developed by people building game-playing programs, and many of these methods will be surveyed and compared here. The balance of the paper contains a study of contemporary methods for searching chess game trees in parallel, using an arbitrary number of independent processors. To make efficient use of these processors, one must have a clear understanding of the basic properties of the trees actually traversed when alpha-beta cutoffs occur. This paper provides such insights and concludes with a brief description of a refinement to a standard parallel search algorithm for this problem. 33 references.

Marsland, T.A.; Campbell, M.

1982-12-01

11

Parallelized direct execution simulation of message-passing parallel programs  

NASA Technical Reports Server (NTRS)

As massively parallel computers proliferate, there is growing interest in findings ways by which performance of massively parallel codes can be efficiently predicted. This problem arises in diverse contexts such as parallelizing computers, parallel performance monitoring, and parallel algorithm development. In this paper we describe one solution where one directly executes the application code, but uses a discrete-event simulator to model details of the presumed parallel machine such as operating system and communication network behavior. Because this approach is computationally expensive, we are interested in its own parallelization specifically the parallelization of the discrete-event simulator. We describe methods suitable for parallelized direct execution simulation of message-passing parallel programs, and report on the performance of such a system, Large Application Parallel Simulation Environment (LAPSE), we have built on the Intel Paragon. On all codes measured to date, LAPSE predicts performance well typically within 10 percent relative error. Depending on the nature of the application code, we have observed low slowdowns (relative to natively executing code) and high relative speedups using up to 64 processors.

Dickens, Phillip M.; Heidelberger, Philip; Nicol, David M.

1994-01-01

12

Toward a Taxonomy of Parallel Tabu Search Heuristics  

Microsoft Academic Search

In this paper we present a classification of parallel tabu search metaheuristicsbased, on the one hand, on the control and communication strategies used in thedesign of the parallel tabu search procedures and, on the other hand, on how the searchspace is partitionned. These criteria are then used to review the parallel tabu searchimplementations described in the literature. The taxonomy is

Teodor Gabriel Crainic; Michel Toulouse; Michel Gendreau

1997-01-01

13

Direct steam generation in parallel pipes  

Microsoft Academic Search

Two-phase flow in parallel pipes is associated with the application of direct steam generation (DSG) by solar heating using parabolic troughs focusing solar power. In this process water is fed into parallel pipes from a common manifold. Owing to local cloud cover or difference in the focusing quality, each pipe may receive a different heating power. In this case the

Sivan Natan; Dvora Barnea; Yehuda Taitel

2003-01-01

14

Asynchronous Parallel Generating Set Search for Linearly-Constrained Optimization.  

National Technical Information Service (NTIS)

Generating set search (GSS) is a family of direct search methods that encompasses generalized pattern search and related methods. We describe an algorithm for asynchronous linearly-constrained GSS, which has some complexities that make it different from b...

J. D. Griffin R. M. Lewis T. G. Kolda

2006-01-01

15

Direct search for light gluinos  

Microsoft Academic Search

We present the results for a direct search for light gluinos through the appearance of ??3?0 with high transverse momentum in the vacuum tank of the NA48 experiment at CERN. We find one event within a lifetime range of 10?9–10?3 s and another one between 10?10–10?9 s. Both events are consistent with the expected background from neutrons in the beam,

V. Fanti; A. Lai; L. Musa; D. Marras; A. Nappi; B. Hay; R. W. Moore; K. N. Moore; D. J. Munday; M. D. Needham; M. A. Parker; T. O. White; S. A. Wotton; J. Andersen; G. Barr; G. Bocquet; J. Bremer; A. Ceccucci; D. Cundy; N. Doble; G. Fischer; W. Funk; L. Gatignon; A. Gianoli; G. Govi; P. Grafström; W. Kubischta; S. Luitz; G. Kesseler; J. P. Matheys; A. Norton; S. Palestini; B. Panzer-Steindel; D. Schinzel; H. Taureg; M. Velasco; O. Vossnack; H. Wahl; G. Wirrer; V. Kekelidze; A. Mestvirishvili; I. Potrebenikov; G. Tatichvili; A. Tkatchev; A. Zinchenko; O. Boyle; V. J. Martin; I. G. Knowles; H. L. C. Parsons; P. Dalpiaz; J. Duclos; P. L. Frabetti; M. Martini; F. Petrucci; M. Porcu; M. Savrié; A. Bizzeti; M. Calvetti; G. Graziani; E. Iacopini; M. Lenti; A. Michetti; H. G. Becker; H. Blümer; P. Buchholz; D. Coward; C. Ebersberger; H. Fox; A. Kalter; K. Kleinknecht; U. Koch; L. Köpke; B. Renk; J. Scheidt; V. Schönharting; I. Schué; R. Wilhelm; A. Winharting; M. Wittgen; J. C. Chollet; S. Crépé; L. Iconomidou-Fayard; L. Fayard; J. Ocariz; G. Unal; D. Vattolo; I. Wingerter; G. Anzivino; P. Cenci; P. Lubrano; M. Pepe; B. Gorini; P. Calafiura; R. Carosi; C. Cerri; M. Cirilli; F. Costantini; R. Fantechi; S. Giudici; I. Mannelli; V. Marzulli; G. Pierazzini; M. Sozzi; J. B. Cheze; J. Cogan; M. De Beer; P. Debu; A. Formica; R. Granier-De-Cassagnac; P. Hristov; E. Mazzucato; B. Peyaud; S. Schanne; R. Turlay; B. Vallage; I. Augustin; M. Bender; M. Holder; M. Ziolkowski; R. Arcidiacono; C. Biino; F. Marchetto; E. Menichetti; J. Nassalski; E. Rondio; M. Szleper; W. Wislicki; S. Wronka; H. Dibon; M. Jeitler; M. Markytan; I. Mikulec; G. Neuhofer; M. Pernicka; A. Taurok

1999-01-01

16

Direct search for light gluinos  

Microsoft Academic Search

We present the results for a direct search for light gluinos through the appearance of $\\\\eta\\\\rightarrow 3\\\\pin$ with high transverse momentum in the vacuum tank of the NA48 experiment at CERN. We find one event within a lifetime range of $10^{-9}-10^{-3}$\\\\,s and another one between $10^{-10}-10^{-9}$\\\\,s. Both events are consistent with the expected background from neutrons in the beam, produced

V Fanti; A Lai; L Musa; D Marras; A Nappi; B Hay; R W Moore; K N Moore; D J Munday; M D Needham; M A Parker; T O White; S A Wotton; J Andersen; Giles David Barr; G Bocquet; J Bremer; Augusto Ceccucci; Donald C Cundy; Niels T Doble; G Fischer; W Funk; L Gatignon; A Gianoli; A Gonidec; G Govi; P Grafström; Werner Kubischta; S Luitz; G Kesseler; J P Matheys; Alan Robert Norton; S Palestini; B Panzer-Steindel; D Schinzel; Hans Taureg; M Velasco; O Vossnack; H Wahl; G Wirrer; V D Kekelidze; A Mestvirishvili; Yu K Potrebenikov; G T Tatishvili; A L Tkachev; A I Zinchenko; O Boyle; V J Martin; I G Knowles; H Parsons; Pietro Dalpiaz; J Duclos; P L Frabetti; M Martini; F Petrucci; M Porcu; M Savrié; A Bizzeti; M Calvetti; G Graziani; E Iacopini; M Lenti; A Michetti; H G Becker; H Blümer; P Buchholz; D H Coward; C Ebersberger; H Fox; A Kalter; K Kleinknecht; U Koch; L Köpke; B Renk; J Scheidt; J Schmidt; V Schönharting; Yu Schué; R Wilhelm; A Winharting; M Wittgen; J C Chollet; S Crépé; L Iconomidou-Fayard; Louis Fayard; J Ocariz; G Unal; D Vattolo; I Wingerter-Seez; Giuseppina Anzivino; P Cenci; P Lubrano; M Pepé; B Gorini; P Calafiura; R Carosi; C Cerri; M Cirilli; F Costantini; R Fantechi; Sergio Giudici; I Mannelli; V M Marzulli; G M Pierazzini; M Sozzi; J B Chèze; J Cogan; M De Beer; P Debu; A Formica; R Granier de Cassagnac; P Z Khristov; E Mazzucato; B Peyaud; S Schanne; René Turlay; B Vallage; I Augustin; M Bender; M Holder; M Ziolkowski; R Arcidiacono; C Biino; F Marchetto; E Menichetti; J P Nassalski; Ewa Rondio; M Szleper; W Wislicki; S Wronka; Heinz Dibon; Manfred Jeitler; Manfred Markytan; I Mikulec; Günther Neuhofer; Manfred Pernicka; Anton Taurok

1998-01-01

17

Asynchronous parallel generating set search for linearly-constrained optimization.  

SciTech Connect

We describe an asynchronous parallel derivative-free algorithm for linearly-constrained optimization. Generating set search (GSS) is the basis of ourmethod. At each iteration, a GSS algorithm computes a set of search directionsand corresponding trial points and then evaluates the objective function valueat each trial point. Asynchronous versions of the algorithm have been developedin the unconstrained and bound-constrained cases which allow the iterations tocontinue (and new trial points to be generated and evaluated) as soon as anyother trial point completes. This enables better utilization of parallel resourcesand a reduction in overall runtime, especially for problems where the objec-tive function takes minutes or hours to compute. For linearly-constrained GSS,the convergence theory requires that the set of search directions conform to the3 nearby boundary. The complexity of developing the asynchronous algorithm forthe linearly-constrained case has to do with maintaining a suitable set of searchdirections as the search progresses and is the focus of this research. We describeour implementation in detail, including how to avoid function evaluations bycaching function values and using approximate look-ups. We test our imple-mentation on every CUTEr test problem with general linear constraints and upto 1000 variables. Without tuning to individual problems, our implementationwas able to solve 95% of the test problems with 10 or fewer variables, 75%of the problems with 11-100 variables, and nearly half of the problems with100-1000 variables. To the best of our knowledge, these are the best resultsthat have ever been achieved with a derivative-free method. Our asynchronousparallel implementation is freely available as part of the APPSPACK software.4

Kolda, Tamara G.; Griffin, Joshua; Lewis, Robert Michael

2007-04-01

18

Methods for Parallelizing Search Paths in Phrasing.  

National Technical Information Service (NTIS)

Many search problems are commonly solved with combinatoric algorithms that unnecessarily duplicate and serialize work at considerable computational expense. There are techniques available that can eliminate redundant computations and perform remaining ope...

C. De Marcken

1993-01-01

19

Parallel Mechanisms Encode Direction in the Retina  

PubMed Central

SUMMARY In the retina, presynaptic inhibitory mechanisms that shape directionally selective (DS) responses in output ganglion cells are well established. However, the nature of inhibition-independent forms of directional selectivity remains poorly defined. Here, we describe a genetically specified set of ON-OFF DS ganglion cells (DSGCs) that code anterior motion. This entire population of DSGCs exhibits asymmetric dendritic arborizations that orientate toward the preferred direction. We demonstrate that morphological asymmetries along with nonlinear dendritic conductances generate a centrifugal (soma-to-dendrite) preference that does not critically depend upon, but works in parallel with the GABAergic circuitry. We also show that in symmetrical DSGCs, such dendritic DS mechanisms are aligned with, or are in opposition to, the inhibitory DS circuitry in distinct dendritic subfields where they differentially interact to promote or weaken directional preferences. Thus, pre- and postsynaptic DS mechanisms interact uniquely in distinct ganglion cell populations, enabling efficient DS coding under diverse conditions.

Trenholm, Stuart; Johnson, Kyle; Li, Xiao; Smith, Robert G.; Awatramani, Gautam B.

2012-01-01

20

Parallel mechanisms encode direction in the retina.  

PubMed

In the retina, presynaptic inhibitory mechanisms that shape directionally selective (DS) responses in output ganglion cells are well established. However, the nature of inhibition-independent forms of directional selectivity remains poorly defined. Here, we describe a genetically specified set of ON-OFF DS ganglion cells (DSGCs) that code anterior motion. This entire population of DSGCs exhibits asymmetric dendritic arborizations that orientate toward the preferred direction. We demonstrate that morphological asymmetries along with nonlinear dendritic conductances generate a centrifugal (soma-to-dendrite) preference that does not critically depend upon, but works in parallel with the GABAergic circuitry. We also show that in symmetrical DSGCs, such dendritic DS mechanisms are aligned with, or are in opposition to, the inhibitory DS circuitry in distinct dendritic subfields where they differentially interact to promote or weaken directional preferences. Thus, pre- and postsynaptic DS mechanisms interact uniquely in distinct ganglion cell populations, enabling efficient DS coding under diverse conditions. PMID:21867884

Trenholm, Stuart; Johnson, Kyle; Li, Xiao; Smith, Robert G; Awatramani, Gautam B

2011-08-25

21

Massively Parallel Direct Simulation of Multiphase Flow  

SciTech Connect

The authors understanding of multiphase physics and the associated predictive capability for multi-phase systems are severely limited by current continuum modeling methods and experimental approaches. This research will deliver an unprecedented modeling capability to directly simulate three-dimensional multi-phase systems at the particle-scale. The model solves the fully coupled equations of motion governing the fluid phase and the individual particles comprising the solid phase using a newly discovered, highly efficient coupled numerical method based on the discrete-element method and the Lattice-Boltzmann method. A massively parallel implementation will enable the solution of large, physically realistic systems.

COOK,BENJAMIN K.; PREECE,DALE S.; WILLIAMS,J.R.

2000-08-10

22

Searching for an Axis-Parallel Shoreline  

NASA Astrophysics Data System (ADS)

We are searching for an unknown horizontal or vertical line in the plane under the competitive framework. We design a framework for lower bounds on all cyclic and monotone strategies that result in two-sequence functionals. For optimizing such functionals we apply a method that combines two main paradigms. The given solution shows that the combination method is of general interest. Finally, we obtain the current best strategy and can prove that this is the best strategy among all cyclic and monotone strategies which is a main step toward a lower bound construction.

Langetepe, Elmar

23

Parallel Breadth-First Search LTL Model-Checking  

Microsoft Academic Search

Abstract: We propose a practical parallel on-the-fly algorithm forenumerative LTL model-checking. The algorithm is designedfor a cluster of workstations communicating viaMPI. The detection of cycles (faulty runs) effectively employsthe so called back-level edges. In particular, a parallellevel-synchronized breadth-first search of the graph isperformed to discover back-level edges. For each level theback-level edges are checked in parallel by a nested depthfirstsearch

Jir Barnat Lubos

2003-01-01

24

MAX search with parallel verification for frame synchronization  

Microsoft Academic Search

This paper proposes a novel frame acquisition method for continuous transmissions in TDM\\/TDMA systems. The approach is based on a multi-dwell procedure, with approximate maximum likelihood criterion (MAX) applied in search mode, followed by a parallel threshold crossing (TC) verification stage. The particular case of single TC verification and the conventional all-TC procedures, which perform TC also in search mode,

Raffaella Pedone; Marco Villanti; Giovanni E. Corazza

2005-01-01

25

A parallelization of the row-searching algorithm  

NASA Astrophysics Data System (ADS)

The problem dealt in this paper concerns the parallelization of the row-searching algorithm which allows the search for linearly dependant rows on a given matrix and its implementation on MPI (Message Passing Interface) environment. This algorithm is largely used in control theory and more specifically in solving the famous diophantine equation. An introduction to the diophantine equation is presented, then two parallelization approaches of the algorithm are detailed. The first distributes a set of rows on processes (processors) and the second makes a distribution per blocks. The sequential algorithm and its two parallel forms are implemented using MPI routines, then modelled using UML (Unified Modelling Language) and finally evaluated using algorithmic complexity.

Yaici, Malika; Khaled, Hayet; Khaled, Zakia; Bentahar, Athmane

2012-11-01

26

Performance Modeling and Analysis of a Massively Parallel Direct - Part 1  

Microsoft Academic Search

Modeling and analysis techniques are used to inves- tigate the performance of a massively parallel version of DIRECT, a global search algorithm widely used in multidisciplinary design optimization applications. Several high-dimensional benchmark functions and real world problems are used to test the design ef- fectiveness under various problem structures. Theo- retical and experimental results are compared for two parallel clusters

Jian He; Alex Verstak; Layne T. Watson; Masha Sosonkina

2009-01-01

27

Web Searching: Innovations, Challenges, and Future Directions.  

ERIC Educational Resources Information Center

Presents an outline for a planned technical session discussing innovations in the Web, the current state of Web searching, challenges, and future directions. Highlights include search engines; an empirical comparison of Web site overview techniques; Federal statistics web sites; and an evaluation of Web search engines from the end-user's…

Su, Louise T.

2000-01-01

28

Parallel Breadth-First Search LTL Model-Checking  

Microsoft Academic Search

We propose a practical parallel on-the-fly algorithm for enumerative LTL model-checking. The algorithm is de- signed for a cluster of workstations communicating via MPI. The detection of cycles (faulty runs) effectively em- ploys the so called back-level edges. In particular, a par- allel level-synchronized breadth-first search of the graph is performed to discover back-level edges. For each level the back-level

Jir ´ i Barnat; Lubos Brim; Jakub Chaloupka

2003-01-01

29

Automatic Generation of Directive-Based Parallel Programs for Shared Memory Parallel Systems  

NASA Technical Reports Server (NTRS)

The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. As great progress was made in hardware and software technologies, performance of parallel programs with compiler directives has demonstrated large improvement. The introduction of OpenMP directives, the industrial standard for shared-memory programming, has minimized the issue of portability. Due to its ease of programming and its good performance, the technique has become very popular. In this study, we have extended CAPTools, a computer-aided parallelization toolkit, to automatically generate directive-based, OpenMP, parallel programs. We outline techniques used in the implementation of the tool and present test results on the NAS parallel benchmarks and ARC3D, a CFD application. This work demonstrates the great potential of using computer-aided tools to quickly port parallel programs and also achieve good performance.

Jin, Hao-Qiang; Yan, Jerry; Frumkin, Michael

2000-01-01

30

Asynchronous parallel generating set search for linearly-constrained optimization.  

SciTech Connect

Generating set search (GSS) is a family of direct search methods that encompasses generalized pattern search and related methods. We describe an algorithm for asynchronous linearly-constrained GSS, which has some complexities that make it different from both the asynchronous bound-constrained case as well as the synchronous linearly-constrained case. The algorithm has been implemented in the APPSPACK software framework and we present results from an extensive numerical study using CUTEr test problems. We discuss the results, both positive and negative, and conclude that GSS is a reliable method for solving small-to-medium sized linearly-constrained optimization problems without derivatives.

Lewis, Robert Michael (; ); Griffin, Joshua D.; Kolda, Tamara Gibson

2006-08-01

31

Parallel processing of shape and texture in haptic search.  

PubMed

In a haptic search task, one has to determine the presence of a target among distractors. It has been shown that if the target differs from the distractors in two properties, shape and texture, performance is better than in both single-property conditions (Van Polanen, Bergmann Tiest, & Kappers, 2013). The search for a smooth sphere among rough cubical distractors was faster than both the searches for a rough sphere (shape information only) and for a smooth cube (texture information only). This effect was replicated in this study as a baseline. The main focus here was to further investigate the nature of this integration. It was shown that performance is better when the two properties are combined in a single target (smooth sphere), than when located in two separate targets (rough sphere and smooth cube) that are simultaneously present. A race model that assumes independent parallel processing of the two properties could explain the enhanced performance with two properties, but this could only take place effectively when the two properties were located in a single target. PMID:24816269

van Polanen, Vonne; Bergmann Tiest, Wouter M; Kappers, Astrid M L

2014-07-01

32

Rapid Acquisition for Direct Sequence Spread-Spectrum Communications Using Parallel SAW Convolvers  

Microsoft Academic Search

In this paper, a technique is described which uses multiple surface acoustic wave (SAW) devices in parallel to reduce the acquisition time of a direct sequence spread-spectrum communication system. Analysis of system performance in both the search and lock modes is presented, and key quantities such as probability of false alarm, probability of correct detection, mean dwell time, and mean

L. B. Milstein; J. Gevargiz; P. K. Das

1985-01-01

33

Nonlinear Programming by Mesh Adaptive Direct Searches.  

National Technical Information Service (NTIS)

This paper is intended not as a survey, but as an introduction to some ideas behind the class of mesh adaptive direct search (MADS) methods. Space limitations dictate a brief description of various key topics to be provided along with several references, ...

M. A. Abramson C. Audet J. J. Dennis

2005-01-01

34

Parallel/distributed direct method for solving linear systems  

NASA Technical Reports Server (NTRS)

A new family of parallel schemes for directly solving linear systems is presented and analyzed. It is shown that these schemes exhibit a near optimal performance and enjoy several important features: (1) For large enough linear systems, the design of the appropriate paralleled algorithm is insensitive to the number of processors as its performance grows monotonically with them; (2) It is especially good for large matrices, with dimensions large relative to the number of processors in the system; (3) It can be used in both distributed parallel computing environments and tightly coupled parallel computing systems; and (4) This set of algorithms can be mapped onto any parallel architecture without any major programming difficulties or algorithmical changes.

Lin, Avi

1990-01-01

35

Directed intermittent search for hidden targets  

NASA Astrophysics Data System (ADS)

We develop and analyze a stochastic model of directed intermittent search for a hidden target on a one-dimensional track. A particle injected at one end of the track randomly switches between a stationary search phase and a mobile, non-search phase that is biased in the anterograde direction. There is a finite possibility that the particle fails to find the target due to an absorbing boundary at the other end of the track or due to competition with other targets. Such a scenario is exemplified by the motor-driven transport of mRNA granules to synaptic targets along a dendrite. We first calculate the hitting probability and conditional mean first passage time (MFPT) for finding a single target. We show that an optimal search strategy does not exist, although for a fixed hitting probability, a unidirectional rather than a partially biased search strategy generates a smaller MFPT. We then extend our analysis to the case of multiple targets, and determine how the hitting probability and MFPT depend on the number of targets.

Bressloff, Paul; Newby, Jay

2009-02-01

36

Direct searches for dark matter: recent results.  

PubMed

There is abundant evidence for large amounts of unseen matter in the universe. This dark matter, by its very nature, couples feebly to ordinary matter and is correspondingly difficult to detect. Nonetheless, several experiments are now underway with the sensitivity required to detect directly galactic halo dark matter through their interactions with matter and radiation. These experiments divide into two broad classes: searches for weakly interacting massive particles (WIMPs) and searches for axions. There exists a very strong theoretical bias for supposing that supersymmetry (SUSY) is a correct description of nature. WIMPs are predicted by this SUSY theory and have the required properties to be dark matter. These WIMPs are detected from the byproducts of their occasional recoil against nucleons. There are efforts around the world to detect these rare recoils. The WIMP part of this overview focuses on the cryogenic dark matter search (CDMS) underway in California. Axions, another favored dark matter candidate, are predicted to arise from a minimal extension of the standard model that explains the absence of the expected large CP violating effects in strong interactions. Axions can, in the presence of a large magnetic field, turn into microwave photons. It is the slight excess of photons above noise that signals the axion. Axion searches are underway in California and Japan. The axion part of this overview focuses on the California effort. Brevity does not allow me to discuss other WIMP and axion searches, likewise for accelerator and satellite based searches; I apologize for their omission. PMID:9419325

Rosenberg, L J

1998-01-01

37

Hadamard NMR spectroscopy for two-dimensional quantum information processing and parallel search algorithms.  

PubMed

Hadamard spectroscopy has earlier been used to speed-up multi-dimensional NMR experiments. In this work, we speed-up the two-dimensional quantum computing scheme, by using Hadamard spectroscopy in the indirect dimension, resulting in a scheme which is faster and requires the Fourier transformation only in the direct dimension. Two and three qubit quantum gates are implemented with an extra observer qubit. We also use one-dimensional Hadamard spectroscopy for binary information storage by spatial encoding and implementation of a parallel search algorithm. PMID:17011221

Gopinath, T; Kumar, Anil

2006-12-01

38

A parallel hybrid local search algorithm for the container loading problem  

Microsoft Academic Search

In this contribution, a parallel hybrid local search algorithm for the three-dimensional contai- ner loading problem (CLP) is proposed. First a simulated annealing method for the CLP is developed, which is then combined with an existing tabu search algorithm to form a hybrid metaheuristic. Finally, parallel versions are introduced for these algorithms. The emphasis is on CLP instances with a

Daniel Mack; Andreas Bortfeldt; Hermann Gehring

2004-01-01

39

Efficient Parallel Algorithm For Direct Numerical Simulation of Turbulent Flows  

NASA Technical Reports Server (NTRS)

A distributed algorithm for a high-order-accurate finite-difference approach to the direct numerical simulation (DNS) of transition and turbulence in compressible flows is described. This work has two major objectives. The first objective is to demonstrate that parallel and distributed-memory machines can be successfully and efficiently used to solve computationally intensive and input/output intensive algorithms of the DNS class. The second objective is to show that the computational complexity involved in solving the tridiagonal systems inherent in the DNS algorithm can be reduced by algorithm innovations that obviate the need to use a parallelized tridiagonal solver.

Moitra, Stuti; Gatski, Thomas B.

1997-01-01

40

EDELWEISS experiment: Direct search for dark matter  

SciTech Connect

The EDELWEISS experiment is aimed at direct searches for nonbaryonic cold dark matter by means of cryogenic germanium detectors. It is deployed at the LSM underground laboratory in the Frejus tunnel, which connects France and Italy. The results of the experimentmade it possible to set a limit on the spin-independent cross section for the scattering of weak-interacting massive particles (WIMP) at a level of 10{sup -6} pb. Data from 21 detectors of total mass about 7 kg are being accumulated at the present time.

Lubashevskiy, A. V., E-mail: alexey.lubashevsky@jinr.ru; Yakushev, E. A. [Joint Institute for Nuclear Research (Russian Federation)

2008-07-15

41

In search of sweet-spots in parallel performance monitoring  

Microsoft Academic Search

Parallel performance monitoring extends parallel measurement systems with infrastructure and interfaces for online performance data access, communication, and analysis. At the same time it raises concerns for the impact on application execution from monitor overhead. The application monitoring scheme parameterized by performance events to monitor, access frequency and the type of data analysis operation defines a set of monitoring requirements.

Aroon Nataraj; Allen D. Malony; Allen Morris; Dorian C. Arnold; Barton P. Miller

2008-01-01

42

Parallel multithreaded IDA* heuristic search: algorithm design and performance evaluation  

Microsoft Academic Search

Due to the witnessed prevalence of the commercial multi-core microprocessors, parallel programming becomes a dire need for efficiently using all available hardware resources for one application. One of the parallel programming approaches is multithreading, which has been proved to play a great role in providing sequential computers with virtual parallelisation, yielding faster execution and easy communication. Such advantageous features are

Basel A. Mahafzah

2011-01-01

43

The perfect search engine is not enough: a study of orienteering behavior in directed search  

Microsoft Academic Search

This paper presents a modified diary study that investigated how people performed personally motivated searches in their email, in their files, and on the Web. Although earlier studies of directed search focused on keyword search, most of the search behavior we observed did not involve keyword search. Instead of jumping directly to their information target using keywords, our participants navigated

Jaime Teevan; Christine Alvarado; Mark S. Ackerman; David R. Karger

2004-01-01

44

A directed search for extraterrestrial laser signals  

NASA Technical Reports Server (NTRS)

The focus of NASA's Search for Extraterrestrial Intelligence (SETI) Program is on microwave frequencies, where receivers have the best sensitivities for the detection of narrowband signals. Such receivers, when coupled to existing radio telescopes, form an optimal system for broad area searches over the sky. For a directed search, however, such as toward specific stars, calculations show that infrared wavelengths can be equally as effective as radio wavelengths for establishing an interstellar communication link. This is true because infrared telescopes have higher directivities (gains) that effectively compensate for the lower sensitivities of infrared receivers. The result is that, for a given level of transmitted power, the signal to noise ratio for communications is equally as good at infrared and radio wavelengths. It should also be noted that the overall sensitivities of both receiver systems are quite close to their respective fundamental limits: background thermal noise for the radio frequency system and quantum noise for the infrared receiver. Consequently, the choice of an optimum communication frequency may well be determined more by the achievable power levels of transmitters rather than the ultimate sensitivities of receivers at any specific frequency. In the infrared, CO2 laser transmitters with power levels greater than 1 MW can already be built on Earth. For a slightly more advanced civilization, a similar but enormously more powerful laser may be possible using a planetary atmosphere rich in CO2. Because of these possibilities and our own ignorance of what is really the optimum search frequency, a search for narrowband signals at infrared frequencies should be a part of a balanced SETI Program. Detection of narrowband infrared signals is best done with a heterodyne receiver functionally identical to a microwave spectral line receiver. We have built such a receiver for the detection of CO2 laser radiation at wavelengths near 10 microns. The spectrometer uses a high-speed HgCdTe diode as the photomixer and a small CO2 laser as the local oscillator. Output signals in the intermediate frequency range 0.1-2.6 GHz are processed by a 1000-channel acousto-optic signal processor. The receiver is being used on a 1.5-m telescope on Mt. Wilson to survey a selected sample of 150 nearby stars. The current status of the work is discussed along with future project plans.

Betz, A.

1991-01-01

45

Tool-path planning for direction-parallel area milling  

Microsoft Academic Search

Presented in the paper is a tool-path planning algorithm for direction-parallel area milling consisting of three modules: (1) finding the optimal inclination; (2) calculating and storing tool-path elements; and (3) tool-path linking. For the optimal inclination, we suggest an algorithm that selects an inclination by reflecting the shape of the machining area as well as the tool-path interval. We make

Sang C. Park; Byoung Kyu Choi

2000-01-01

46

Nearest Neighbor Search Applications for the Terasys Massively Parallel Workstation.  

National Technical Information Service (NTIS)

The Terasys workstation is a massively parallel computer developed at IDA's Center for Computing Sciences. This report, based on a project conducted in IDA's Computer and Software Engineering Division, presents an overview of the Terasys workstation and d...

E. W. Johnson

1996-01-01

47

Parallelization of sequential Gaussian, indicator and direct simulation algorithms  

NASA Astrophysics Data System (ADS)

Improving the performance and robustness of algorithms on new high-performance parallel computing architectures is a key issue in efficiently performing 2D and 3D studies with large amount of data. In geostatistics, sequential simulation algorithms are good candidates for parallelization. When compared with other computational applications in geosciences (such as fluid flow simulators), sequential simulation software is not extremely computationally intensive, but parallelization can make it more efficient and creates alternatives for its integration in inverse modelling approaches. This paper describes the implementation and benchmarking of a parallel version of the three classic sequential simulation algorithms: direct sequential simulation (DSS), sequential indicator simulation (SIS) and sequential Gaussian simulation (SGS). For this purpose, the source used was GSLIB, but the entire code was extensively modified to take into account the parallelization approach and was also rewritten in the C programming language. The paper also explains in detail the parallelization strategy and the main modifications. Regarding the integration of secondary information, the DSS algorithm is able to perform simple kriging with local means, kriging with an external drift and collocated cokriging with both local and global correlations. SIS includes a local correction of probabilities. Finally, a brief comparison is presented of simulation results using one, two and four processors. All performance tests were carried out on 2D soil data samples. The source code is completely open source and easy to read. It should be noted that the code is only fully compatible with Microsoft Visual C and should be adapted for other systems/compilers.

Nunes, Ruben; Almeida, José A.

2010-08-01

48

Oriented modulation for watermarking in direct binary search halftone images.  

PubMed

In this paper, a halftoning-based watermarking method is presented. This method enables high pixel-depth watermark embedding, while maintaining high image quality. This technique is capable of embedding watermarks with pixel depths up to 3 bits without causing prominent degradation to the image quality. To achieve high image quality, the parallel oriented high-efficient direct binary search (DBS) halftoning is selected to be integrated with the proposed orientation modulation (OM) method. The OM method utilizes different halftone texture orientations to carry different watermark data. In the decoder, the least-mean-square-trained filters are applied for feature extraction from watermarked images in the frequency domain, and the naïve Bayes classifier is used to analyze the extracted features and ultimately to decode the watermark data. Experimental results show that the DBS-based OM encoding method maintains a high degree of image quality and realizes the processing efficiency and robustness to be adapted in printing applications. PMID:22581134

Guo, Jing-Ming; Su, Chang-Cheng; Liu, Yun-Fu; Lee, Hua; Lee, Jiann-Der

2012-09-01

49

Direct drive digital servo press with high parallel control  

NASA Astrophysics Data System (ADS)

Direct drive digital servo press has been developed as the university-industry joint research and development since 1998. On the basis of this result, 4-axes direct drive digital servo press has been developed and in the market on April of 2002. This servo press is composed of 1 slide supported by 4 ball screws and each axis has linearscale measuring the position of each axis with high accuracy less than ?m order level. Each axis is controlled independently by servo motor and feedback system. This system can keep high level parallelism and high accuracy even with high eccentric load. Furthermore the 'full stroke full power' is obtained by using ball screws. Using these features, new various types of press forming and stamping have been obtained by development and production. The new stamping and forming methods are introduced and 'manufacturing' need strategy of press forming with high added value and also the future direction of press forming are also introduced.

Murata, Chikara; Yabe, Jun; Endou, Junichi; Hasegawa, Kiyoshi

2013-12-01

50

Low-power parallel tree architecture for full search block-matching motion estimation  

Microsoft Academic Search

In this paper, a novel low-power parallel tree architecture is pro- posed for full search block-matching motion estimation. The par- allel tree architecture exploits the spatial data correlations between parallel candidate block searches for data sharing, which effec- tively eliminates huge amount of data access bandwidth while con- sumes fewer hardware resources compared with array-based archi- tectures. Combining with adaptive

Siou-shen Lin; Po-chih Tseng; Liang-gee Chen

2004-01-01

51

On the Potentials of Parallelizing Large Neighbourhood Search for Rich Vehicle Routing Problems  

Microsoft Academic Search

\\u000a In this paper we present preliminary results on parallelizing the Large Neighbourhood Search heuristic (LNS) for the Vehicle\\u000a Routing Problem with Pickup and Delivery and Time Windows (VRPPDTW) using pb.net, a framework for easy and efficient parallelization\\u000a of problem solving heuristics.

Paul Bartodziej; Ulrich Derigs; Ulrich Vogel

2010-01-01

52

Parallel algorithms and architectures for very fast AI search  

SciTech Connect

A wide range of problems in natural and artificial intelligence, computer vision, computer graphics, database engineering, operations research, symbolic logic, robot manipulation and hardware design automation are special cases of Consistent Labeling Problems (CLP). CLP has long been viewed as an efficient computational model based on a unit constraint relation containing 2N-tuples of units and labels which specifies which N-tuples of labels are compatible with which N-tuples of units. Due to high computation cost and design complexity, most currently best-known algorithms and computer architectures have usually proven infeasible for solving the consistent labeling problems. Efficiency in CLP computation during the last decade has only been improved a few times. This research presents several parallel algorithms and computer architectures for solving CLP within a parallel processing framework. For problems of practical interest, 4 to 10 orders of magnitude of efficiency improvement can be easily reached. Several simple wafer scale computer architectures are given which implement these parallel algorithms at a surprisingly low cost.

Gu, J.

1989-01-01

53

A Parallel Search-and-Learn Technique for Solving Large Scale TSP  

Microsoft Academic Search

In this paper, we describe a parallel search-and-learn technique for obtaining high quality solutions to the Travelling Salesperson Problem (TSP). The combi- natorial search space is decomposed so that multiple processors can simultaneously look for local optimal solutions in the subspaces. The local optima are then compared to \\

C. P. Ravikumar

1993-01-01

54

A PARALLEL GRASP FOR THE STEINER TREE PROBLEM IN GRAPHS USING A HYBRID LOCAL SEARCH STRATEGY  

Microsoft Academic Search

In this paper, we present a parallel greedy randomized adaptive search pro- cedure (GRASP) for the Steiner problem in graphs. GRASP is a two phase metaheuristic. In the rst phase, solutions are constructed using a greedy randomized procedure. Local search is applied in the second phase, leading to a local minimum with respect to a specied neighborhood. In the Steiner

S. L. MARTINS; M. G. C. RESENDE; C. C. RIBEIRO; P. M. PARDALOS

1999-01-01

55

A Parallel Grasp for the Steiner Tree Problem in Graphs Using a Hybrid Local Search Strategy  

Microsoft Academic Search

In this paper, we present a parallel greedy randomized adaptive search procedure (GRASP) for the Steiner problem in graphs. GRASP is a two-phase metaheuristic. In the first phase, solutions are constructed using a greedy randomized procedure. Local search is applied in the second phase, leading to a local minimum with respect to a specified neighborhood. In the Steiner problem in

S. L. Martins; M. G. C. Resende; C. C. Ribeiro; P. M. Pardalos

2000-01-01

56

Serial and Parallel Attentive Visual Searches: Evidence from Cumulative Distribution Functions of Response Times  

ERIC Educational Resources Information Center

Participants searched a visual display for a target among distractors. Each of 3 experiments tested a condition proposed to require attention and for which certain models propose a serial search. Serial versus parallel processing was tested by examining effects on response time means and cumulative distribution functions. In 2 conditions, the…

Sung, Kyongje

2008-01-01

57

Sub-micron parallel laser direct-write  

NASA Astrophysics Data System (ADS)

We have developed a modified laser induced forward transfer (LIFT) technique which allows for the parallel deposition of hundreds of sub-micron features. The approach utilizes a self-assembled monolayer of monodisperse polystyrene microspheres as the focusing element. A monolayer of close-packed microspheres is formed on top of an ultra-thin quartz support (25 ?m thick), and a metallic thin film is then deposited on the underside of the quartz. This approach is different from previous parallel microsphere-assisted LIFT experiments that required the deposition of metal directly onto the surface of the periodic microsphere structure. For this study, an 800 nm, 130 fs laser pulse was directed toward the microsphere layer to focus the incident laser beam through the thin quartz layer to the quartz-metal interface. At this interface, a portion of the thin metal film was ablated directly below each microsphere, resulting in an array of holes in the thin metal film. The metal removed from the film was patterned onto a receiving substrate to form an array of discrete deposits. In some cases, a two layer thin film was utilized resulting in the forward transfer of bilayer metal features. The holes and deposited features were characterized using scanning electron microscopy, atomic force microscopy, and scanning Auger electron spectroscopy. The diameter of the holes (0.5-5 ?m) as well as the diameter (0.9-5 ?m) and quality of the deposited metallic features were modulated by varying the sphere size, incident laser energy, and material composition.

Othon, Christina M.; Laracuente, Arnaldo; Ladouceur, H. D.; Ringeisen, Bradley R.

2008-12-01

58

Mesh Adaptive Direct Search Algorithms for Constrained Optimization  

Microsoft Academic Search

This paper introduces the Mesh Adaptive Direct Search (MADS) class of algorithms for nonlinear optimization. MADS extends the Generalized Pattern Search (GPS) class by allowing local exploration, called polling, in an asymptotically dense set of directions in the space of optimization variables. This means that under certain hypotheses, including a weak constraint qualification due to Rockafellar, MADS can treat constraints

Charles Audet; J. E. Dennis Jr.

2006-01-01

59

A tabu search algorithm for the multi-stage parallel machine problem with limited buffer capacities  

Microsoft Academic Search

Abstract We investigate the problem,of scheduling,N jobs on parallel machines,in L successive stages with limited buffer capacities between,stages. The primary,objective is to find a schedule that would,minimize,the makespan.,This problem is shown,to be NP -hard in the strong sense. We develop a tabu search algorithm,for this problem,in which the search is limited to the space of permutation,vectors of size N .

Bagas Wardono; Yahya Fathi

2004-01-01

60

Attentional Control via Parallel Target-Templates in Dual-Target Search  

PubMed Central

Simultaneous search for two targets has been shown to be slower and less accurate than independent searches for the same two targets. Recent research suggests this ‘dual-target cost’ may be attributable to a limit in the number of target-templates than can guide search at any one time. The current study investigated this possibility by comparing behavioural responses during single- and dual-target searches for targets defined by their orientation. The results revealed an increase in reaction times for dual- compared to single-target searches that was largely independent of the number of items in the display. Response accuracy also decreased on dual- compared to single-target searches: dual-target accuracy was higher than predicted by a model restricting search guidance to a single target-template and lower than predicted by a model simulating two independent single-target searches. These results are consistent with a parallel model of dual-target search in which attentional control is exerted by more than one target-template at a time. The requirement to maintain two target-templates simultaneously, however, appears to impose a reduction in the specificity of the memory representation that guides search for each target.

Barrett, Doug J. K.; Zobay, Oliver

2014-01-01

61

A Parallel Framework for Multipoint Spiral Search in ab Initio Protein Structure Prediction.  

PubMed

Protein structure prediction is computationally a very challenging problem. A large number of existing search algorithms attempt to solve the problem by exploring possible structures and finding the one with the minimum free energy. However, these algorithms perform poorly on large sized proteins due to an astronomically wide search space. In this paper, we present a multipoint spiral search framework that uses parallel processing techniques to expedite exploration by starting from different points. In our approach, a set of random initial solutions are generated and distributed to different threads. We allow each thread to run for a predefined period of time. The improved solutions are stored threadwise. When the threads finish, the solutions are merged together and the duplicates are removed. A selected distinct set of solutions are then split to different threads again. In our ab initio protein structure prediction method, we use the three-dimensional face-centred-cubic lattice for structure-backbone mapping. We use both the low resolution hydrophobic-polar energy model and the high-resolution 20 × 20 energy model for search guiding. The experimental results show that our new parallel framework significantly improves the results obtained by the state-of-the-art single-point search approaches for both energy models on three-dimensional face-centred-cubic lattice. We also experimentally show the effectiveness of mixing energy models within parallel threads. PMID:24744779

Rashid, Mahmood A; Shatabda, Swakkhar; Newton, M A Hakim; Hoque, Md Tamjidul; Sattar, Abdul

2014-01-01

62

Astronomical guidance for directed searches for continuous gravitational waves  

NASA Astrophysics Data System (ADS)

The LIGO Scientic Collaboration and Virgo Collaboration have published a search for continuous gravitational-waves from the non-pulsing neutron star in supernova remnant Cas A and, more recently, from the galactic center. More such searches, where the direction is known but no pulsar timing is available, are under way. I describe the astronomical criteria for good targets for such gravitational-wave searches, list classes of astronomical objects, and give examples of each class.

Owen, Benjamin

2014-01-01

63

Phase and chemical equilibrium calculations by direct search optimization  

Microsoft Academic Search

Direct search optimization is applied to Gibbs free energy minimization to determine phase compositions at equilibrium. The method selected is the random search optimization procedure of Luus and Jaakola, which has been shown to be successful for solving difficult global optimization problems. It is implemented in a multipass fashion where the region size for a variable at the beginning of

Yeow Peng Lee; Gade Pandu Rangaiah; Rein Luus

1999-01-01

64

Synthesis of digital holograms by direct binary search  

SciTech Connect

A new approach to the design of computer-generated holograms makes optimal use of the available device resolution. An iterative search algorithm minimizes an error criterion by directly manipulating the binary hologram and observing the effect on the desired reconstruction. Several measures of error and efficiency useful in assessing the optimality of digital holograms are defined. Methods for designing digital holograms that are based on projections and error diffusion are presented as established techniques for comparison to direct binary search.

Seldowitz, M.A.; Allebach, J.P.; Sweeney, D.W.

1987-07-15

65

Expanding The Search For Galaxies At z 7-10 With New NICMOS Parallel Fields  

Microsoft Academic Search

We have carried out a search for z 7-10 galaxies in 14.4 square arcminutes of new NICMOS parallel imaging taken in the Great Observatories Origins Deep Survey (GOODS, 5.9 sq. arcmin), the Cosmic Origins Survey (COSMOS, 7.2 sq. arcmin), and SSA22 (1.3 sq. arcmin). These images reach 5 sigma sensitivities of J110 = 26.0-27.5 (AB), and when combined, they increase

Alaina L. Henry; Brian Siana; Matthew A. Malkan; Matthew L. N. Ashby; Carrie R. Bridge; Ranga-Ram Chary; James W. Colbert; Mauro Giavalisco; Harry I. Teplitz; Patrick J. McCarthy

2009-01-01

66

Parallel Ear Decomposition Search (EDS) and st-Numbering in Graphs  

Microsoft Academic Search

[LEC-67] linear time serial algorithm for testing planarity of graphs uses the linear timeserial algorithm of [ET-76] for st-numbering. This st-numbering algorithm is based ondepth-first search (DFS). A known conjecture states that DFS, which is a key techniquein designing serial algorithms, is not amenable to poly-log time parallelism using"around linearly" (or even polynomially) many processors. The first contribution of thispaper

Yael Maon; Baruch Schieber; Uzi Vishkin

1986-01-01

67

A direct method for string to deterministic finite automaton conversion for fast text searching  

SciTech Connect

This paper describes a simple technique for generating a minimum state deterministic finite automation (DFA) directly from a restricted set of regular expressions. The resulting DFA is used for string searches that do not alter the target text and require only a single pass through the input. The technique is used for very fast, mixed or same case, single or multiple string searches. The technique is also capable of directly converting multiple strings with wild card character specifiers by constructing parallel DFAs. Construction of the automation is performed in a time proportional to the length of the regular expression. Algorithms are given for construction of the automatons and recognizers. Although the regular expression to DFA parser does not support all classes of regular expressions, it supports a sufficient subset to make it useful for the most commonly encountered text searching functions.

Berlin, G.J.

1991-01-01

68

Extended Aperture 2-D Direction Finding With a Two-Parallel-Shape-Array Using Propagator Method  

Microsoft Academic Search

In this letter, we propose a two-parallel-shape array geometry, consisting of sensors spaced much farther apart than a half-wavelength, to improve estimation accuracy via aperture extension for two-dimensional (2D) direction finding. First, the subarray parallel with the x-axis is employed to extract automatically paired high-variance but unambiguous y-axis direction cosines and low-variance but cyclically ambiguous x-axis direction cosines. Then, the

Jin He; Zhong Liu

2009-01-01

69

Direct stereo radargrammetric processing using massively parallel processing  

NASA Astrophysics Data System (ADS)

Synthetic Aperture Radar (SAR) offers many ways to reconstruct digital surface models (DSMs). The two most commonly used methods are SAR interferometry (InSAR) and stereo radargrammetry. Stereo radargrammetry is a very stable and reliable process and is far less affected by temporal decorrelation compared with InSAR. It is therefore often used for DSM generation in heavily vegetated areas. However, stereo radargrammetry often produces rather noisy DSMs, sometimes containing large outliers. In this manuscript, we present a new approach for stereo radargrammetric processing, where the homologous points between the images are found by geocoding large amount of points. This offers a very flexible approach, allowing the simultaneous processing of multiple images and of cross-heading image pairs. Our approach relies on a good initial geocoding accuracy of the data and on very fast processing using a massively parallel implementation. The approach is demonstrated using TerraSAR-X images from Mount Song, China, and from Trento, Italy.

Balz, Timo; Zhang, Lu; Liao, Mingsheng

2013-05-01

70

Priming of luminance-defined motion direction in visual search  

Microsoft Academic Search

Features that we have recently attended to strongly influence how we allocate visual attention across a subsequently viewed\\u000a visual scene. Here, we investigate the characteristics of any such repetition effects during visual search for Gabor patch\\u000a targets drifting in the odd direction relative to a set of distractors. The results indicate that repetition of motion direction\\u000a has a strong effect

Árni KristjÁnsson; Andri Bjarnason; Árni Bragi Hjaltason; Bryndís Gyda Stefánsdóttir

2009-01-01

71

The JCSG MR pipeline: optimized alignments, multiple models and parallel searches  

PubMed Central

The success rate of molecular replacement (MR) falls considerably when search models share less than 35% sequence identity with their templates, but can be improved significantly by using fold-recognition methods combined with exhaustive MR searches. Models based on alignments calculated with fold-recognition algorithms are more accurate than models based on conventional alignment methods such as FASTA or BLAST, which are still widely used for MR. In addition, by designing MR pipelines that integrate phasing and automated refinement and allow parallel processing of such calculations, one can effectively increase the success rate of MR. Here, updated results from the JCSG MR pipeline are presented, which to date has solved 33 MR structures with less than 35% sequence identity to the closest homologue of known structure. By using difficult MR problems as examples, it is demonstrated that successful MR phasing is possible even in cases where the similarity between the model and the template can only be detected with fold-recognition algorithms. In the first step, several search models are built based on all homologues found in the PDB by fold-recognition algorithms. The models resulting from this process are used in parallel MR searches with different combinations of input parameters of the MR phasing algorithm. The putative solutions are subjected to rigid-body and restrained crystallo­graphic refinement and ranked based on the final values of free R factor, figure of merit and deviations from ideal geometry. Finally, crystal packing and electron-density maps are checked to identify the correct solution. If this procedure does not yield a solution with interpretable electron-density maps, then even more alternative models are prepared. The structurally variable regions of a protein family are identified based on alignments of sequences and known structures from that family and appropriate trimmings of the models are proposed. All combinations of these trimmings are applied to the search models and the resulting set of models is used in the MR pipeline. It is estimated that with the improvements in model building and exhaustive parallel searches with existing phasing algorithms, MR can be successful for more than 50% of recognizable homologues of known structures below the threshold of 35% sequence identity. This implies that about one-third of the proteins in a typical bacterial proteome are potential MR targets.

Schwarzenbacher, Robert; Godzik, Adam; Jaroszewski, Lukasz

2008-01-01

72

Physician Assistant Self-Directed Search Holland Codes  

ERIC Educational Resources Information Center

A mailed survey was used to identify the vocational interests of physician assistants (PAs) as measured by Holland's Self-Directed Search (SDS) Form R. A random sample of 2,323 PAs from the American Academy of Physician Assistants' mailing list was sent a survey to identify a pool of practicing PAs satisfied with their career choices for further…

LaBarbera, Dawn M.

2005-01-01

73

Vocational Interests (The Self-Directed Search) of Female Carpenters  

ERIC Educational Resources Information Center

In this national sample of female carpenters (N=411) who began their apprenticeship with the United Brotherhood of Carpenters during the 1990s in the United States, the author provides a profile of female carpenters' vocational interests (The Self-Directed Search). The vocational interests of 137 male carpenters also were gathered for comparison.…

Swan, Kathy C.

2005-01-01

74

Synthesis of digital holograms by direct binary search  

Microsoft Academic Search

A new approach to the design of computer-generated holograms makes optimal use of the available device resolution. An iterative search algorithm minimizes an error criterion by directly manipulating the binary hologram and observing the effect on the desired reconstruction. Several measures of error and efficiency useful in assessing the optimality of digital holograms are defined. Methods for designing digital holograms

Michael A. Seldowitz; Jan P. Allebach; Donald W. Sweeney

1987-01-01

75

A method of deriving parallel algorithms for direct integration in structural dynamics  

Microsoft Academic Search

A method of deriving parallel algorithms from well-established conventional direct integration algorithms such as the Wislon theta method, Newmark beta method etc. is presented. The new algorithms are able to effectively exploit the power of parallel computers for the dynamic analysis of large-scale structures, and may be more efficient than the conventional methods, even on uniprocessors. It appears that the

R. S. Harichandran; Binshan Ye

1993-01-01

76

Direct Numerical Simulations of Separated and Separated-Reattaching Flows on Massively Parallel Processing Computers.  

National Technical Information Service (NTIS)

Direct numerical simulations of separated-reattaching and separated flows have been performed on massively parallel processing computers. Two basic geometrical configurations have been studied: the separated-reattaching flow past a normal flat plate with ...

F. M. Najjar

1994-01-01

77

A scalable parallel Poisson solver for three-dimensional problems with one periodic direction  

Microsoft Academic Search

A code for the direct numerical simulation (DNS) of incompressible flows with one periodic direction has been developed. It provides a fairly good performance on both Beowulf clusters and supercomputers. Since the code is fully explicit, from a parallel point-of-view, the main bottleneck is the Poisson equation. To solve it, a Fourier diagonalization is applied in the periodic direction to

A. Gorobets; F. X. Trias; M. Soria; A. Oliva

2010-01-01

78

Parallel tabu search algorithm for the permutation flow shop problem with criterion of minimizing sum of job completion times  

Microsoft Academic Search

This paper deals with an intelligent algorithm dedicated for the use in manufacturing systems. Particularly, it develops the fast parallel tabu search algorithm to minimize sum of job completion times in the flow shop scheduling problem. So called multimoves are used, that consist in performing several independent moves simultaneously, which allow one to guide very quickly the search process to

W. Bozejko; J. Pempera

2008-01-01

79

High-performance parallel sparse-direct triangular solves (Invited)  

NASA Astrophysics Data System (ADS)

Geophysical inverse problems are increasingly posed in the frequency domain in a manner which requires solving many challenging heterogeneous 3D Helmholtz or linear elastic wave equations at each iteration. One effective means of solving such problems, at least when there is no large-scale internal resonance, is to use moving-PML "sweeping preconditioners". Each application of the sweeping preconditioner involves performing many modest-sized sparse-direct triangular solves -- unfortunately, one at a time. While P. et al. have shown that, with a careful implementation of a distributed sparse-direct solver [1,2], challenging 3D problems approaching a billion degrees of freedom can be solved in a few minutes using less than 10,000 cores, this talk discusses how to leverage the existence of many right-hand sides in order to increase the performance of the preconditioner applications by orders of magnitude. [1] http://github.com/poulson/Clique [2] http://github.com/poulson/PSP

Poulson, J.; Ying, L.

2013-12-01

80

Detector developing for directional dark matter search with nuclear emulsion  

NASA Astrophysics Data System (ADS)

We are planing the directional dark matter search experiment with nuclear emulsion. Recoiled atoms inside of the emulsion fly several hundred nm, and it is too short to detect with usual emulsion. Fine crystal emulsion was needed to detect such tracks. We developed new method to produce them and succeeded to make crystals small as 20 nm at the minimum size. We also study several methods to improve sensitivity and reduce background noise to survey very interesting cross section region.

Asada, T.; Naka, T.; Kuwabara, K.; Katsuragawa, T.; Yoshimoto, M.; Hakamata, K.; Ishikawa, M.; Nakamura, M.; Sato, O.; Nakano, T.

2013-12-01

81

A method of deriving parallel algorithms for direct integration in structural dynamics  

NASA Astrophysics Data System (ADS)

A method of deriving parallel algorithms from well-established conventional direct integration algorithms such as the Wislon theta method, Newmark beta method etc. is presented. The new algorithms are able to effectively exploit the power of parallel computers for the dynamic analysis of large-scale structures, and may be more efficient than the conventional methods, even on uniprocessors. It appears that the parallel algorithms can be made to maintain the property of unconditional stability displayed by the conventional methods. The parallel algorithms are derived by splitting the stiffness, damping and mass matrices such that the dynamic equations of motion can be cast in block diagonal form. The splitting of the matrices corresponds to physical subdomains of the structure. Each set of block diagonal equations can be solved indpendently of the others and therefore the computations can be performed in parallel. However, a predictor-corrector approach requiring iterations within a time step must be used for acceptable accuracy. The method described in this paper is derived from the Wilson theta method and is called the 'parallel Wilson theta method'. A simple numerical example is used to illustrate the accuracy of the parallel method, which is comparable to the conventional method when a sufficient number of iterations is used. Preliminary computations were performed on a BBN GP-1000 distributed-memory parallel computer to assess the performance of the parallel algorithm. The proposed method is especially suited for large-scale non-linear structural dynamics problems.

Harichandran, R. S.; Ye, Binshan

1993-12-01

82

Retrieval comparison of EndNote to search MEDLINE (Ovid and PubMed) versus searching them directly.  

PubMed

Using EndNote version 7.0, the authors tested the search capabilities of the EndNote search engine for retrieving citations from MEDLINE for importation into EndNote, a citation management software package. Ovid MEDLINE and PubMed were selected for the comparison. Several searches were performed on Ovid MEDLINE and PubMed using EndNote as the search engine, and the same searches were run on both Ovid and PubMed directly. Findings indicate that it is preferable to search MEDLINE directly rather than using EndNote. The publishers of EndNote do warn its users about the limitations of their product as a search engine when searching external databases. In this article, the limitations of EndNote as a search engine for searching MEDLINE were explored as related to MeSH, non-MeSH, citation verification, and author searching. PMID:15364649

Gall, Carole; Brahmi, Frances A

2004-01-01

83

Privacy-Preserving Location-Based Query Using Location Indexes and Parallel Searching in Distributed Networks  

PubMed Central

An efficient location-based query algorithm of protecting the privacy of the user in the distributed networks is given. This algorithm utilizes the location indexes of the users and multiple parallel threads to search and select quickly all the candidate anonymous sets with more users and their location information with more uniform distribution to accelerate the execution of the temporal-spatial anonymous operations, and it allows the users to configure their custom-made privacy-preserving location query requests. The simulated experiment results show that the proposed algorithm can offer simultaneously the location query services for more users and improve the performance of the anonymous server and satisfy the anonymous location requests of the users.

Liu, Lei; Zhao, Jing

2014-01-01

84

Privacy-preserving location-based query using location indexes and parallel searching in distributed networks.  

PubMed

An efficient location-based query algorithm of protecting the privacy of the user in the distributed networks is given. This algorithm utilizes the location indexes of the users and multiple parallel threads to search and select quickly all the candidate anonymous sets with more users and their location information with more uniform distribution to accelerate the execution of the temporal-spatial anonymous operations, and it allows the users to configure their custom-made privacy-preserving location query requests. The simulated experiment results show that the proposed algorithm can offer simultaneously the location query services for more users and improve the performance of the anonymous server and satisfy the anonymous location requests of the users. PMID:24790579

Zhong, Cheng; Liu, Lei; Zhao, Jing

2014-01-01

85

Parallel-Up Structure Evidences the Molecular Directionality during Biosynthesis of Bacterial Cellulose  

Microsoft Academic Search

The ``parallel-up'' packing in cellulose Ialpha and Ibeta unit cells was experimentally demonstrated by a combination of direct-staining the reducing ends of cellulose chains and microdiffraction-tilting electron crystallographic analysis. Microdiffraction investigation of nascent bacterial cellulose microfibrils showed that the reducing end of the growing cellulose chains points away from the bacterium, and this provides direct evidence that polymerization by the

Makiko Koyama; William Helbert; Tomoya Imai; Junji Sugiyama; Bernard Henrissat

1997-01-01

86

Hybrid simulated annealing and direct search method for nonlinear unconstrained global optimization  

Microsoft Academic Search

In this article we give a new approach of hybrid direct search methods with meta-heuristics of simulated annealing for finding a global minimum of a nonlinear function with continuous variables. First, we suggest a Simple Direct Search (SDS) method, which comes from some ideas of other well-known direct search methods. Since our goal is to find global minima and the

Abdel-Rahman Hedar; Masao Fukushima

2002-01-01

87

Direct CP violation searches in charmless hadronic B meson decays  

Microsoft Academic Search

We search for direct CP violation in charmless hadronic B decays observed in a sample of about 22.7 million BBbar pairs collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e+e- collider. We measure the following charge asymmetries: ACP(B+\\/--->eta'K+\\/-)=-0.11+\\/-0.11+\\/-0.02, ACP(B+\\/--->omegapi+\\/-)=-0.01 + 0.29 - 0.31+\\/-0.03, ACP(B+\\/--->phiK+\\/-)=-0.05+\\/-0.20+\\/-0.03, ACP(B+\\/--->phiK*+\\/-)=-0.43 + 0.36 - 0.30+\\/-0.06, and ACP(B0-->phiK*0)=0.00+\\/-0.27+\\/-0.03.

B. Aubert; D. Boutigny; J.-M. Gaillard; A. Hicheur; Y. Karyotakis; J. P. Lees; P. Robbe; V. Tisserand; A. Palano; A. Pompili; G. P. Chen; J. C. Chen; N. D. Qi; G. Rong; P. Wang; Y. S. Zhu; G. Eigen; B. Stugu; G. S. Abrams; A. W. Borgland; A. B. Breon; D. N. Brown; J. Button-Shafer; R. N. Cahn; A. R. Clark; M. S. Gill; A. V. Gritsan; Y. Groysman; R. G. Jacobsen; R. W. Kadel; J. Kadyk; L. T. Kerth; Yu. G. Kolomensky; J. F. Kral; C. Leclerc; M. E. Levi; G. Lynch; P. J. Oddone; M. Pripstein; N. A. Roe; A. Romosan; M. T. Ronan; V. G. Shelkov; A. V. Telnov; W. A. Wenzel; P. G. Bright-Thomas; T. J. Harrison; C. M. Hawkes; D. J. Knowles; S. W. O'Neale; R. C. Penny; A. T. Watson; N. K. Watson; T. Deppermann; K. Goetzen; H. Koch; M. Kunze; B. Lewandowski; K. Peters; H. Schmuecker; M. Steinke; N. R. Barlow; W. Bhimji; N. Chevalier; P. J. Clark; W. N. Cottingham; B. Foster; C. Mackay; F. F. Wilson; K. Abe; C. Hearty; T. S. Mattison; J. A. McKenna; D. Thiessen; S. Jolly; J. A. McKenna; V. E. Blinov; A. D. Bukin; D. A. Bukin; A. R. Buzykaev; V. B. Golubev; V. N. Ivanchenko; A. A. Korol; E. A. Kravchenko; A. P. Onuchin; S. I. Serednyakov; I. Skovpen; V. I. Telnov; A. N. Yushkov; M. Chao; D. Kirkby; A. J. Lankford; M. Mandelkern; S. McMahon; D. P. Stoker; K. Arisaka; C. Buchanan; S. Chun; D. B. MacFarlane; S. Prell; G. Raven; V. Sharma; C. Campagnari; B. Dahmes; P. A. Hart; N. Kuznetsova; S. L. Levy; A. Lu; J. D. Richman; W. Verkerke; J. Beringer; A. M. Eisner; M. Grothe; C. A. Heusch; W. S. Lockman; T. Pulliam; T. Schalk; A. Seiden; M. Turri; W. Walkowiak; D. C. Williams; M. G. Wilson; E. Chen; G. P. Dubois-Felsmann; A. Dvoretskii; D. G. Hitlin; J. Oyang; F. C. Porter; A. Ryd; A. Samuel; R. Y. Zhu; T. L. Geld; S. Jayatilleke; G. Mancinelli; B. T. Meadows; M. D. Sokolo; T. Barillari; P. Bloom; M. O. Dima; W. T. Ford; A. Olivas; P. Rankin; J. Roy; J. G. Smith; W. C. van Hoek; J. Blouw; J. L. Harton; M. Krishnamurthy; A. Soer; W. H. Toki; R. J. Wilson; J. Zhang; T. Brandt; M. Sokoloff; T. Barillari; P. Bloom; S. Fahey; D. Johnson; U. Nauenberg; S. Sen; J. Smith; D. Wagner; A. Soffer; J. Zhang; J. Brose; T. Colberg; M. Dickopp; R. Dubitzky; A. Hauke; E. Maly; R. Müller-Pfefferkorn; S. Otto; K. Schubert; R. Schwierz; B. Spaan; L. Wilden; D. Bernard; G. Bonneaud; F. Brochard; J. Cohen-Tanugi; S. Ferrag; E. Roussot; S. T’Jampens; Ch. Thiebaux; G. Vasileiadis; M. Verderi; A. Anjomshoaa; R. Bernet; A. Khan; D. Lavin; F. Muheim; S. Playfer; J. Swain; J. Tinslay; M. Falbo; C. Borean; C. Bozzi; S. Dittongo; L. Piemontese; E. Treadwell; F. Anulli; R. Baldini-Ferroli; A. Calcaterra; R. de Sangro; D. Falciai; G. Finocchiaro; P. Patteri; I. Peruzzi; M. Piccolo; Y. Xie; A. Zallo; S. Bagnasco; A. Buzzo; R. Contri; G. Crosetti; M. Lo Vetere; M. Macri; M. Monge; S. Passaggio; F. Pastore; C. Patrignani; M. Piccolo; E. Robutti; A. Santroni; S. Tosi; M. Morii; R. Bartoldus; U. Mallik; J. Cochran; H. Crawley; P.-A. Fischer; J. Lamsa; W. Meyer; E. Rosenberg; G. Grosdidier; C. Hast; A. Höcker; H. Lacker; S. Laplace; V. Lepeltier; A. Lutz; S. Plaszczynski; M. Schune; S. Trincaz-Duvoid; G. Wormser; R. Bionta; V. Brigljevi?; D. Lange; M. Mugge; K. van Bibber; D. Wright; A. Bevan; J. Fry; E. Gabathuler; R. Gamet; M. George; M. Kay; D. Payne; R. Sloane; C. Touramanis; M. Aspinwall; D. Bowerman; P. Dauncey; U. Egede; I. Eschrich; N. Gunawardane; J. Nash; P. Sanders; D. Smith; D. Azzopardi; J. Back; P. Dixon; P. Harrison; R. Potter; H. Shorthouse; P. Strother; P. Vidal; G. Cowan; S. George; M. Green; A. Kurup; C. Marker; P. McGrath; T. McMahon; S. Ricciardi; F. Salvatore; I. Scott; G. Vaitsas; D. Brown; C. Davis; J. Allison; R. Barlow; J. Boyd; A. Forti; J. Fullwood; F. Jackson; G. Lafferty; N. Savvas; J. Weatherall; J. Williams; A. Farbin; A. Jawahery; V. Lillard; J. Olsen; D. Roberts; J. Schieck; G. Blaylock; S. Hertzbach; R. Kofler; V. Koptchev; T. Moore; H. Staengle; S. Willocq; B. Brau; R. Cowan; G. Sciolla; F. Taylor; R. Yamamoto; M. Milek; P. Patel; F. Palombo; J. Bauer; L. Cremaldi; V. Eschenburg; R. Kofler; J. Reidy; D. Sanders; D. Summers; J. Martin; J. Nief; R. Seitz; P. Taras; V. Zacek; H. Nicholson; C. Sutton; C. Cartaro; N. Cavallo; G. De Nardo; F. Fabozzi; C. Gatto; L. Lista; P. Paolucci; D. Piccolo; C. Sciacca; J. LoSecco; J. Alsmiller; T. Gabriel; T. Handler; J. Brau; R. Frey; E. Grauges; M. Iwasaki; N. Sinev; D. Strom; F. Colecchia; F. Dal Corso; A. Dorigo; F. Galeazzi; M. Margoni; G. Michelon; M. Morandin; M. Posocco; M. Rotondo; F. Simonetto; R. Stroili; E. Torassa; C. Voci; M. Benayoun; H. Briand; J. Chauveau; P. David; Ch. de la Vaissière; L. Del Buono; O. Hamon; F. Le Diberder; Ph. Leruste; J. Ocariz; L. Roos; J. Stark; P. Manfredi; V. Re; V. Speziali; E. Frank; L. Gladney; Q. Guo; J. Panetta; C. Angelini; G. Batignani; S. Bettarini; M. Bondioli; M. Carpinelli; F. Forti; M. Giorgi; A. Lusiani; F. Martinez-Vidal

2002-01-01

88

Direct observation of parallel folding pathways revealed using a symmetric repeat protein system.  

PubMed

Although progress has been made to determine the native fold of a polypeptide from its primary structure, the diversity of pathways that connect the unfolded and folded states has not been adequately explored. Theoretical and computational studies predict that proteins fold through parallel pathways on funneled energy landscapes, although experimental detection of pathway diversity has been challenging. Here, we exploit the high translational symmetry and the direct length variation afforded by linear repeat proteins to directly detect folding through parallel pathways. By comparing folding rates of consensus ankyrin repeat proteins (CARPs), we find a clear increase in folding rates with increasing size and repeat number, although the size of the transition states (estimated from denaturant sensitivity) remains unchanged. The increase in folding rate with chain length, as opposed to a decrease expected from typical models for globular proteins, is a clear demonstration of parallel pathways. This conclusion is not dependent on extensive curve-fitting or structural perturbation of protein structure. By globally fitting a simple parallel-Ising pathway model, we have directly measured nucleation and propagation rates in protein folding, and have quantified the fluxes along each path, providing a detailed energy landscape for folding. This finding of parallel pathways differs from results from kinetic studies of repeat-proteins composed of sequence-variable repeats, where modest repeat-to-repeat energy variation coalesces folding into a single, dominant channel. Thus, for globular proteins, which have much higher variation in local structure and topology, parallel pathways are expected to be the exception rather than the rule. PMID:24988356

Aksel, Tural; Barrick, Doug

2014-07-01

89

A direct-execution parallel architecture for the Advanced Continuous Simulation Language (ACSL)  

NASA Technical Reports Server (NTRS)

A direct-execution parallel architecture for the Advanced Continuous Simulation Language (ACSL) is presented which overcomes the traditional disadvantages of simulations executed on a digital computer. The incorporation of parallel processing allows the mapping of simulations into a digital computer to be done in the same inherently parallel manner as they are currently mapped onto an analog computer. The direct-execution format maximizes the efficiency of the executed code since the need for a high level language compiler is eliminated. Resolution is greatly increased over that which is available with an analog computer without the sacrifice in execution speed normally expected with digitial computer simulations. Although this report covers all aspects of the new architecture, key emphasis is placed on the processing element configuration and the microprogramming of the ACLS constructs. The execution times for all ACLS constructs are computed using a model of a processing element based on the AMD 29000 CPU and the AMD 29027 FPU. The increase in execution speed provided by parallel processing is exemplified by comparing the derived execution times of two ACSL programs with the execution times for the same programs executed on a similar sequential architecture.

Carroll, Chester C.; Owen, Jeffrey E.

1988-01-01

90

Parallel Directionally Split Solver Based on Reformulation of Pipelined Thomas Algorithm  

NASA Technical Reports Server (NTRS)

In this research an efficient parallel algorithm for 3-D directionally split problems is developed. The proposed algorithm is based on a reformulated version of the pipelined Thomas algorithm that starts the backward step computations immediately after the completion of the forward step computations for the first portion of lines This algorithm has data available for other computational tasks while processors are idle from the Thomas algorithm. The proposed 3-D directionally split solver is based on the static scheduling of processors where local and non-local, data-dependent and data-independent computations are scheduled while processors are idle. A theoretical model of parallelization efficiency is used to define optimal parameters of the algorithm, to show an asymptotic parallelization penalty and to obtain an optimal cover of a global domain with subdomains. It is shown by computational experiments and by the theoretical model that the proposed algorithm reduces the parallelization penalty about two times over the basic algorithm for the range of the number of processors (subdomains) considered and the number of grid nodes per subdomain.

Povitsky, A.

1998-01-01

91

Efficient Parallel Algorithms for Computing All Pair Shortest Paths in Directed Graphs  

Microsoft Academic Search

We present parallel algorithms for computing all pair shortest paths in directed graphs. Our algorithm has time complexity O. f.n\\/= pC I.n\\/ log n\\/ on the PRAM using p processors, where I.n\\/ is log n on the EREW PRAM, log logn on the CCRW PRAM, f.n\\/ is o.n3\\/. On the randomized CRCW PRAM we are able to achieve time complexity

Yijie Han; Victor Y. Pan; John H. Reif

1997-01-01

92

SUPREM-DSMC: A New Scalable, Parallel, Reacting, Multidimensional Direct Simulation Monte Carlo Flow Code  

NASA Technical Reports Server (NTRS)

An AFRL/NRL team has recently been selected to develop a scalable, parallel, reacting, multidimensional (SUPREM) Direct Simulation Monte Carlo (DSMC) code for the DoD user community under the High Performance Computing Modernization Office (HPCMO) Common High Performance Computing Software Support Initiative (CHSSI). This paper will introduce the JANNAF Exhaust Plume community to this three-year development effort and present the overall goals, schedule, and current status of this new code.

Campbell, David; Wysong, Ingrid; Kaplan, Carolyn; Mott, David; Wadsworth, Dean; VanGilder, Douglas

2000-01-01

93

Parallel spatial direct numerical simulations on the Intel iPSC/860 hypercube  

NASA Technical Reports Server (NTRS)

The implementation and performance of a parallel spatial direct numerical simulation (PSDNS) approach on the Intel iPSC/860 hypercube is documented. The direct numerical simulation approach is used to compute spatially evolving disturbances associated with the laminar-to-turbulent transition in boundary-layer flows. The feasibility of using the PSDNS on the hypercube to perform transition studies is examined. The results indicate that the direct numerical simulation approach can effectively be parallelized on a distributed-memory parallel machine. By increasing the number of processors nearly ideal linear speedups are achieved with nonoptimized routines; slower than linear speedups are achieved with optimized (machine dependent library) routines. This slower than linear speedup results because the Fast Fourier Transform (FFT) routine dominates the computational cost and because the routine indicates less than ideal speedups. However with the machine-dependent routines the total computational cost decreases by a factor of 4 to 5 compared with standard FORTRAN routines. The computational cost increases linearly with spanwise wall-normal and streamwise grid refinements. The hypercube with 32 processors was estimated to require approximately twice the amount of Cray supercomputer single processor time to complete a comparable simulation; however it is estimated that a subgrid-scale model which reduces the required number of grid points and becomes a large-eddy simulation (PSLES) would reduce the computational cost and memory requirements by a factor of 10 over the PSDNS. This PSLES implementation would enable transition simulations on the hypercube at a reasonable computational cost.

Joslin, Ronald D.; Zubair, Mohammad

1993-01-01

94

Direct Searches for Scalar Leptoquarks at the Run II Tevatron  

SciTech Connect

This dissertation sets new limits on the mass of the scalar leptoquark from direct searches carried out at the Run II CDF detector using data from March 2001 to October 2003. The data analyzed has a total time-integrated measured luminosity of 198 pb{sup -1} of p{bar p} collisions with {radical}s = 1.96 TeV. Leptoquarks are assumed to be pair-produced and to decay into a lepton and a quark of the same generation. They consider two possible leptoquark decays: (1) {beta} = BR(LQ {yields} {mu}q) = 1.0, and (2) {beta} = BR(LQ {yields} {mu}q) = 0.5. For the {beta} = 1 channel, they focus on the signature represented by two isolated high-p{sub T} muons and two isolated high-p{sub T} jets. For the {beta} = 1/2 channel, they focus on the signature represented by one isolated high-p{sub T} muon, large missing transverse energy, and two isolated high-p{sub T} jets. No leptoquark signal is experimentally detected for either signature. Using the next to leading order theoretical cross section for scalar leptoquark production in p{bar p} collisions [1], they set new mass limits on second generation scalar leptoquarks. They exclude the existence of second generation scalar leptoquarks with masses below 221(175) GeV/c{sup 2} for the {beta} = 1(1/2) channels.

Ryan, Daniel E.; /Tufts U.

2004-11-01

95

Direct searches for scalar leptoquarks at the Run II tevatron  

NASA Astrophysics Data System (ADS)

This dissertation sets new limits on the mass of the scalar leptoquark from direct searches carried out at the Run II CDF detector using data from March 2001 to October 2003. The data analysed has a total time-integrated measured luminosity of 198 pb-1 of pp¯ collisions with s = 1.96 TeV. Leptoquarks are assumed to be pair-produced and to decay into a lepton and a quark of the same generation. We consider two possible leptoquark decays: (1) beta = BR(LQ ? muq ) = 1.0, and (2) beta = BR(LQ ? muq ) = 0.5. For the beta = 1 channel, we focus on the signature represented by two isolated high-pT muons and two isolated high-pT jets. For the beta = 1/2 channel, we focus on the signature represented by one isolated high-pT muon, large missing transverse energy, and two isolated high-p T jets. No leptoquark signal is experimentally detected for either signature. Using the next to leading order theoretical cross section for scalar leptoquark production in pp¯ collisions [1], we set new mass limits on second generation scalar leptoquarks. We exclude the existence of second generation scalar leptoquarks with masses below 221(175) GeV/c2 for the beta = 1(1/2) channels.

Ryan, Daniel Edward

96

A direct search for neutralino production at LEP  

Microsoft Academic Search

A search has been performed for the production of neutralinos (chi, chi') in e+e- annihilation at energies near the Z0 pole. No evidence for these particles was found either in searches for events with two acoplanar jets, low visible energy, and missing pt (sensitive to Z0-->chichi'-->chichiff) or in searches for single-photon events (sensitive to Z0-->chichi'-->chichigamma). Model independent upper limits (at

M. Z. Akrawy; Gideon Alexander; J. Allison; P. P. Allport; K. J. Anderson; J. C. Armitage; Geoffrey T J Arnison; P. Ashton; Georges Azuelos; J. T. M. Baines; A. H. Ball; J. Banks; G. J. Barker; R. J. Barlow; J Richard Batley; J. Becker; T. Behnke; K. W. Bell; G. Bella; Siegfried Bethke; O. Biebel; U. Binder; Ian J Bloodworth; P. Bock; Horst Breuker; R. M. Brown; R. Brun; A. Buijs; Helfried J Burckhart; P. Capiluppi; R. K. Carnegie; A. A. Carter; J. R. Carter; C. Y. Chang; D. G. Charlton; J. T. M. Chrin; P. E. L. Clarke; I. Cohen; W. J. Collins; J. E. Conboy; M. Couch; M. Coupland; M. Cuffiani; S. Dado; G. M. Dallavalle; P. Debu; M. M. Deninno; A. Dieckmann; Michael Dittmar; M. S. Dixit; E. Duchovni; I. P. Duerdoth; D. J. P. Dumas; H. El Mamouni; P. A. Elcombe; P. G. Estabrooks; E. Etzion; Franco Luigi Fabbri; Philippe Farthouat; H. M. Fischer; D. G. Fong; M. T. French; C. Fukunaga; A. Gaidot; O. Ganel; J. W. Gary; J. Gascon; N. I. Geddes; C. N. P. Gee; C. Geich-Gimbel; S. W. Gensler; F. X. Gentit; G. Giacomelli; V. Gibson; W. R. Gibson; James D Gillies; J. Goldberg; M. J. Goodrick; W. Gorn; D. Granite; E. Gross; Jacob Grunhaus; H. Hagedorn; J. Hagemann; M. Hansroul; C. K. Hargrove; I. Harrus; J. Hart; P. M. Hattersley; M. Hauschild; C. M. Hawkes; E. Heflin; Richard J Hemingway; R. D. Heuer; J. C. Hill; S. J. Hillier; C. Ho; J. D. Hobbs; P. R. Hobson; D. Hochman; B. Holl; R James Homer; S. R. Hou; C. P. Howarth; R E Hughes-Jones; P. Igo-Kemenes; H. Ihssen; D. C. Imrie; A. Jawahery; P. W. Jeffreys; H. Jeremie; Martin Paul Jimack; M. Jobes; R. W. L. Jones; P. Jovanovic; D A Karlen; K. Kawagoe; T. Kawamoto; R. G. Kellogg; B. W. Kennedy; C. Kleinwort; D. E. Klem; G. Knop; T. Kobayashi; T. P. Kokott; L. Köpke; R V Kowalewski; H. Kreutzmann; J Von Krogh; M. Kuwano; P. Kyberd; G. D. Lafferty; F. Lamarche; W. J. Larson; J. G. Layter; P. Le Du; P. Leblanc; A. M. Lee; M. H. Lehto; D. Lellouch; P. Lennert; L. Lessard; L. Levinson; S. L. Lloyd; F. K. Loebinger; J. M. Lorah; B. Lorazo; M. J. Losty; J. Ludwig; J. Ma; A. A. MacBeth; M. Mannelli; S. Marcellini; G. Maringer; A. J. Martin; J. P. Martin; T. Mashimo; P. Mättig; U. Maur; T. J. McMahon; J. R. McNutt; A. C. McPherson; F. Meijers; D. Menszner; F. S. Merritt; H. Mes; A. Michelini; R. P. Middleton; G. Mikenberg; D. J. Miller; C. Milstene; M. Minowa; W. Mohr; A. Montanari; T. Mori; M. W. Moss; P. G. Murphy; W. J. Murray; B. Nellen; H. H. Nguyen; M. Nozaki; A. J. P. O'Dowd; S. W. O'Neale; B. P. O'Neill; F. G. Oakham; F. Odorici; M. Ogg; H. Oh; M. J. Oreglia; S. Orito; J. P. Pansart; G. N. Patrick; S. J. Pawley; P. Pfister; J. E. Pilcher; J. L. Pinfold; D. E. Plane; B. Poli; A. Pouladdej; T. W. Pritchard; G. Quast; J. Raab; M. W. Redmond; D. L. Rees; M. Regimbald; K. Riles; C. M. Roach; S. A. Robins; A. Rollnik; J. M. Roney; S. Rossberg; A. M. Rossi; P. Routenburg; K. Runge; O. Runolfsson; S. Sanghera; R. A. Sansum; M. Sasaki; B. J. Saunders; A. D. Schaile; O. Schaile; W. Schappert; P. Scharff-Hansen; S. Schreiber; J. Schwarz; A. Shapira; B. C. Shen; P. Sherwood; A. Simon; G. P. Siroli; A. Skuja; A. M. Smith; T. J. Smith; G. A. Snow; R. W. Springer; M. Sproston; K. Stephens; H. E. Stier; R. Ströhmer; D. Strom; H. Takeda; T. Takeshita; T. Tsukamoto; M. F. Turner; G. Tysarczyk-Niemeyer; D. van den Plas; G. J. van Dalen; G. Vasseur; C. J. Virtue; H. von der Schmitt; A. Wagner; C. Wahl; C. P. Ward; D. R. Ward; J. Waterhouse; P. M. Watkins; A. T. Watson; N. K. Watson; M. Weber; S. Weisz; P. S. Wells; N. Wermes; M. Weymann; G. W. Wilson; J. A. Wilson; I. Wingerter; V.-H. Winterer; N. C. Wood; S. Wotton; B. Wuensch; T. R. Wyatt; R. Yaari; Y. Yang; G. Yekutieli; T. Toshida; W. Zeuner; G. T. Zorn

1990-01-01

97

Limitations on the Parallel Guidance of Visual Search: Color × Color and Orientation × Orientation Conjuctions  

Microsoft Academic Search

In visual search for a conjunction it is much more difficult to search for the conjunction of 2 colors or 2 orientations than for Color × Orientation or Color × Shape conjunctions. The result is not limited to particular colors or shapes. Two colors cannot occupy the same spatial location in Color × Color searches. However, Experiments 6 and 7

Jeremy M. Wolfe; Karen P. Yu; Marian I. Stewart; Amy D. Shorter; Stacia R. Friedman-Hill; Kyle R. Cave

1990-01-01

98

A direct search for new charged heavy leptons at LEP  

Microsoft Academic Search

Results are presented from a search for a new charged heavy lepton in e+e- annihilation. The data were taken with the OPAL detector at LEP during a scan of the Z0 resonance. Two independent search techniques were used, one looking for events with large missing energy and missing momentum transverse to the beam, and the other for events with isolated

M. Z. Akrawy; Gideon Alexander; J. Allison; P. P. Allport; K. J. Anderson; J. C. Armitage; Geoffrey T J Arnison; P. Ashton; Georges Azuelos; J. T. M. Baines; A. H. Ball; J. Banks; G. J. Barker; R. J. Barlow; J Richard Batley; G. Bavaria; F. Beck; K. W. Bell; G. Bella; Siegfried Bethke; O. Biebel; I. J. Bloddworth; P. Bock; Horst Breuker; R. M. Brown; R. Brun; A. Buijs; Helfried J Burckhart; P. Capiluppi; R. K. Carnegie; A. A. Carter; J. R. Carter; C. Y. Chang; D. G. Charlton; J. T. M. Chrin; I. Cohen; J. E. Conboy; M. Couch; M. Coupland; M. Cuffiani; S. Dado; G. M. Dallavalle; O. W. Davies; M. M. Deninno; A. Dieckmann; Michael Dittmar; M. S. Dixit; D. Duchesneau; E. Duchovni; I. P. Duerdoth; D J P Dumas; H. El Mamouni; P. A. Elcombe; P. G. Estabrooks; E. Etzion; Franco Luigi Fabbri; Philippe Farthouat; H. M. Fischer; D. G. Fong; M. T. French; C. Fukunaga; B. Gandois; O. Ganel; J. W. Gary; N. I. Geddes; C. N. P. Gee; C. Geich-Gimbel; S. W. Gensler; F. X. Gentit; G. Giacomelli; W. R. Gibson; James D Gillies; J. Goldberg; M. J. Goodrick; W. Gorn; D. Granite; E. Gross; P. Grosse-Wiesmann; Jacob Grunhaus; H. Hagedorn; J. Hagemann; M. Hansroul; C. K. Hargrove; J. Hart; P. M. Hattersley; D. Hatzifotiadou; M. Hauschild; C. M. Hawkes; E. Heflin; J. Heintze; Richard J Hemingway; R. D. Heuer; J. C. Hill; S. J. Hillier; P. S. Hinde; C. Ho; J. D. Hobbs; P. R. Hobson; D. Hochman; B. Holl; R James Homer; S. R. Hou; C. P. Howarth; R. E. Hughes-Jones; P. Igo-Kemenes; M. Imori; D. C. Imrie; A. Jawahery; P. W. Jeffreys; H. Jeremie; Martin Paul Jimack; E. Jin; M. Jobes; R. W. L. Jones; P. Jovanovic; D A Karlen; K. Kawagoe; T. Kawamoto; R. G. Kellogg; B. W. Kennedy; C. Kleinwort; D. E. Klem; G. Knop; T. Kobayashi; L. Köpke; T. P. Kokott; M. Koshiba; R V Kowalewski; H. Kreutzmann; J. von Krogh; J. Kroll; P. Kyberd; G. D. Lafferty; F. Lamarche; W. J. Larson; M. M. B. Lasota; J. G. Layter; P. Le Du; P. Leblanc; Daniel Lellouch; P. Lennert; L. Lessard; L. Levinson; S. L. Lloyd; F. K. Loebinger; J. M. Lorah; B. Lorazo; Michael J Losty; J. Ludwig; J. Ma; A. A. MacBeth; M. Mannelli; S. Marcellini; G. Maringer; J. P. Martin; T. Mashimo; P. Mättig; U. Maur; T. J. McMahon; A. C. McPherson; F. Meijers; D. Menszner; F. S. Merritt; H. Mes; A. Michellini; R. P. Middleton; G. Mikenberg; D. J. Miller; C. Milstene; M. Minowa; W. Mohr; A. Montanari; T. Mori; M. W. Moss; A. Muller; P. G. Murphy; W. J. Murray; B. Nellen; H. H. Nguyen; M. Nozaki; A. J. P. O'Dowd; S. W. O'Neale; B P O'Neill; F. G. Oakham; F. Odorici; M. Ogg; H. Oh; M. J. Oreglia; S. Orito; G. N. Patrick; S. J. Pawley; J. E. Pilcher; J. L. Pinfold; D. E. Plane; B. Poli; A. Possoz; A. Pouladdej; T. W. Pritchard; G. Quast; J. Raab; M. W. Redmond; D. L. Rees; M. Regimbald; K. Riles; C. M. Roach; F. Roehner; A. Rollnik; J. M. Roney; A. M. Rossi; P. Routenburg; K. Runge; O. Runolfsson; S. Sanghera; R. A. Sansum; M. Sasaki; B. J. Saunders; A. D. Schaile; O. Schaile; W. Schappert; P. Scharff-Hansen; H. von der Schmitt; S. Schreiber; J. Schwarz; A. Shapira; B. C. Shen; P. Sherwood; A. Simon; G. P. Siroli; A M Smith; A. M. Smith; T. J. Smith; G. A. Snow; E. J. Spreadbury; R. W. Springer; M. Sproston; K. Stephens; J. Steuerer; H. E. Stier; R. Ströhmer; D. Strom; H. Takeda; T. Takeshita; T. Tsukamoto; M. F. Turner; G. Tysarczyk; D. van den Plas; G. J. Vandalen; C. J. Virtue; A. Wagner; C. Wahl; H. Wang; C. P. Ward; D. R. Ward; J. Waterhouse; P. M. Watkins; A. T. Watson; N. K. Watson; M. Weber; S. Weisz; N. Wermes; M. Weymann; G. W. Wilson; J. A. Wilson; I. Wingerter; V.-H. Winterer; N. C. Wood; S. Wotton; B. Wuensch; T. R. Wyatt; R. Yaari; H. Yamashita; Y. Yang; G. Yekutieli; W. Zeuner; G. T. Zorn; S. Zylberajch

1990-01-01

99

Parallel computing of a digital hologram and particle searching for microdigital-holographic particle-tracking velocimetry  

SciTech Connect

We have developed a parallel algorithm for microdigital-holographic particle-tracking velocimetry. The algorithm is used in (1) numerical reconstruction of a particle image computer using a digital hologram, and (2) searching for particles. The numerical reconstruction from the digital hologram makes use of the Fresnel diffraction equation and the FFT (fast Fourier transform),whereas the particle search algorithm looks for local maximum graduation in a reconstruction field represented by a 3D matrix. To achieve high performance computing for both calculations (reconstruction and particle search), two memory partitions are allocated to the 3D matrix. In this matrix, the reconstruction part consists of horizontally placed 2D memory partitions on the x-y plane for the FFT, whereas, the particle search part consists of vertically placed 2D memory partitions set along the z axes.Consequently, the scalability can be obtained for the proportion of processor elements,where the benchmarks are carried out for parallel computation by a SGI Altix machine.

Satake, Shin-ichi; Kanamori, Hiroyuki; Kunugi, Tomoaki; Sato, Kazuho; Ito, Tomoyoshi; Yamamoto, Keisuke

2007-02-01

100

Obstacles May Facilitate and Direct DNA Search by Proteins  

PubMed Central

DNA recognition by DNA-binding proteins (DBPs), which is a pivotal event in most gene regulatory processes, is often preceded by an extensive search for the correct site. A facilitated diffusion process in which a DBP combines three-dimensional diffusion in solution with one-dimensional sliding along DNA has been suggested to explain how proteins can locate their target sites on DNA much faster than predicted by three-dimensional diffusion alone. Although experimental and theoretical studies have recently advanced understanding of the biophysical principles underlying the search mechanism, the process under in vivo cellular conditions is poorly understood. In this study, we used various computational approaches to explore how the presence of obstacle proteins on the DNA influences search efficiency. At a low obstacle occupancy (i.e., when few obstacles occupy sites on the DNA), sliding by the searching DBP may be confined, which may impair search efficiency. The obstacles, however, can be bypassed during hopping events, and the number of bypasses is larger for higher obstacle occupancies. Dynamism on the part of the obstacles may even further facilitate search kinetics. Our study shows that the nature and efficiency of the search process may be governed not only by the intrinsic properties of the DBP and the salt concentration of the medium, but also by the in vivo association of DNA with other macromolecular obstacles, their location, and occupancy.

Marcovitz, Amir; Levy, Yaakov

2013-01-01

101

Obstacles may facilitate and direct DNA search by proteins.  

PubMed

DNA recognition by DNA-binding proteins (DBPs), which is a pivotal event in most gene regulatory processes, is often preceded by an extensive search for the correct site. A facilitated diffusion process in which a DBP combines three-dimensional diffusion in solution with one-dimensional sliding along DNA has been suggested to explain how proteins can locate their target sites on DNA much faster than predicted by three-dimensional diffusion alone. Although experimental and theoretical studies have recently advanced understanding of the biophysical principles underlying the search mechanism, the process under in vivo cellular conditions is poorly understood. In this study, we used various computational approaches to explore how the presence of obstacle proteins on the DNA influences search efficiency. At a low obstacle occupancy (i.e., when few obstacles occupy sites on the DNA), sliding by the searching DBP may be confined, which may impair search efficiency. The obstacles, however, can be bypassed during hopping events, and the number of bypasses is larger for higher obstacle occupancies. Dynamism on the part of the obstacles may even further facilitate search kinetics. Our study shows that the nature and efficiency of the search process may be governed not only by the intrinsic properties of the DBP and the salt concentration of the medium, but also by the in vivo association of DNA with other macromolecular obstacles, their location, and occupancy. PMID:23663847

Marcovitz, Amir; Levy, Yaakov

2013-05-01

102

Direct and Inverse Kinematics of a Novel Tip-Tilt-Piston Parallel Manipulator  

NASA Technical Reports Server (NTRS)

Closed-form direct and inverse kinematics of a new three degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base-mounted; higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of tangent of half-angle between one of the limbs and the base plane. Hence, there are at most 16 assembly configurations for the manipulator. In addition, it is shown that the 16 solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented.

Tahmasebi, Farhad

2004-01-01

103

Parallel direct laser writing in three dimensions with spatially dependent aberration correction.  

PubMed

We propose a hologram design process which aims at reducing aberrations in parallel three-dimensional direct laser writing applications. One principle of the approach is to minimise the diffractive power of holograms while retaining the degree of parallelisation. This reduces focal distortion caused by chromatic aberration. We address associated problems such as the zero diffraction order and aberrations induced by a potential refractive index mismatch between the immersion medium of the microscope objective and the fabrication substrate. Results from fabrication in diamond, fused silica and lithium niobate are presented. PMID:20941005

Jesacher, Alexander; Booth, Martin J

2010-09-27

104

Fabrication of Si-nozzles for parallel mechano-electrospinning direct writing  

NASA Astrophysics Data System (ADS)

Nozzles with micro-scale orifices drive high-resolution printing techniques for generating micro- to nano-scale droplets/lines. This paper presents the fabrication and application of Si-nozzles in mechano-electrospinning (MES). The fabrication process mainly consists of photolithography, Au deposition, inductively coupled plasma, and polydimethylsiloxane encapsulation. The 6 wt% polyethylene oxide solution is adopted to study the electrospinning behaviour and the relations between fibre diameter and process parameters in MES. A fibre grid with 250 µm spacing is able to be direct written, and the diameters are less than 3 µm. To improve the printing efficiency, positioning accuracy and flexibility, a rotatable multi-nozzle is adopted. The distance between parallel lines reduces sharply from 4.927 to 0.308 mm with the rotating angle increasing from 0° to 87°, and the fibre grids with tunable distance are achieved. This method paves the way for fabrication of addressable Si-nozzle array in parallel MES direct writing.

Pan, Yanqiao; Huang, YongAn; Bu, Ningbin; Yin, Zhouping

2013-06-01

105

HYPER-HEURISTICS: AN EMERGING DIRECTION IN MODERN SEARCH TECHNOLOGY  

Microsoft Academic Search

This chapter introduces and overviews an emerging methodology in search and optimisation. One of the key aims of these new approaches, which have been termed hyper-heuristics, is to raise the level of generality at which optimisation systems can operate. An objective is that hyper-heuristics will lead to more general systems that are able to handle a wide range of problem

Edmund Burke; Emma Hart; G raham Kendall; Peter Ross; Sonia Schulenburg

2003-01-01

106

Neutrinoless double beta decay and direct searches for neutrino mass  

Microsoft Academic Search

Study of the neutrinoless double beta decay and searches for the manifestation of the neutrino mass in ordinary beta decay are the main sources of information about the absolute neutrino mass scale, and the only practical source of information about the charge conjugation properties of the neutrinos. Thus, these studies have a unique role in the plans for better understanding

Craig Aalseth; Henning Back; Loretta Dauwe; David Dean; Guido Drexlin; Yuri Efremenko; Hiro Ejiri; Steven Elliott; Jon Engel; Brian Fujikawa; Reyco Henning; G. W. Hoffmann; Karol Lang; Kevin Lesko; Tadafumi Kishimoto; Harry Miley; Rick Norman; Silvia Pascoli; Serguey Petcov; Andreas Piepke; Werner Rodejohann; David Saltzberg; Sean Sutton; Petr Vogel; Ray Warner; John Wilkerson; Lincoln Wolfenstein

2004-01-01

107

Directed search for plant constituents: a case study concerning flavonoids in Norway spruce  

Microsoft Academic Search

The reported content of flavonoids in the needles of Norway spruce, Picea abies, has been used as a basis for a directed search for compounds previously undetected in this species. Combined with advanced chromatographic methods and sensitive detection techniques, the directed search approach assisted in the identification of the novel flavonols, myricetin 3- O- (6?-acetylglucoside) and syringetin 7- O-glucoside, and

Rune Slimestad; George W. Francis; Øyvind M. Andersen

1999-01-01

108

Optimization by Direct Search: New Perspectives on Some Classical and Modern Methods  

Microsoft Academic Search

Direct search methods are best known as unconstrained optimization techniques that do not explicitly use derivatives. Direct search methods were formally proposed and widely applied in the 1960s but fell out of favor with the mathematical optimization community by the early 1970s because they lacked coherent mathematical analysis. Nonetheless, users remained loyal to these methods, most of which were easy

Tamara G. Kolda; Robert Michael Lewis

2003-01-01

109

Parallel implicit algorithms for direct numerical simulations of hypersonic boundary layer stability and transition  

NASA Astrophysics Data System (ADS)

Due to the progress in computer technology in recent years, distributed memory parallel computer systems are rapidly gaining importance in direct numerical simulation (DNS) of the stability and transition of compressible boundary layers. In most works, explicit methods have mainly been used in such simulations to advance the compressible Navier-Stokes equations in time. However, the small wall-normal grid sizes for viscous flow simulations impose severe stability restriction on the allowable time steps in simulations using explicit method. This requires implicit treatment to the numerical methods. Although fully implicit methods are often used in steady-flow calculations to remove the stability restriction on time steps, they are seldom used in transient flow simulations because the time steps used in time-accurate calculations are often not large enough to offset high computational cost of using fully implicit methods. In this thesis, we present an efficient high-order semi-implicit method, which only treats the stiff terms implicitly, for the DNS study the hypersonic boundary-layer receptivity to freestream disturbances over blunt bodies. It is shown that the semi-implicit method can meet the requirements for both computational efficiency and numerical accuracy in the DNS studies. However, we can not implement our semi-implicit method on single computer to solve unsteady Navier-Stokes equations for the direct numerical simulation of supersonic and hypersonic boundary layer flows on parallel computers directly. The semi-implicit algorithm has to be modified to achieve the communications among processors in solving the global block linear systems. In this thesis, a divide and conquer (DAC) method is used to parallelly solve the block linear system from the semi-implicit method. A parallel Fourier collocation method is also implemented in the periodic spanwise direction. It is shown that by implementing the new parallel semi-implicit scheme the simulations of compressible transient flow can benefit greatly from parallel computer systems by increasing both simulation sizes and speed while maintaining high temporal accuracy. To implement our new numerical methods on the numerical studies of compressible boundary layer stability and transitions, numerical simulations of the receptivity process of hypersonic boundary layer flows over 3-D blunt leading edges are chosen to be investigated because the receptivity phenomena are much more complex and currently not well understood. In this thesis, parametric simulations of receptivity freestream disturbances which includes fast acoustic waves, vorticity waves and entropy waves for Mach 15 flow over 3-D blunt leading edges have been carried out by using our new methods. The results show that initial transient growth generated and developed inside the hypersonic boundary layer near the leading edge can be observed in the receptivity of freestream standing vorticity or entropy waves, but not acoustic waves or traveling waves. It has been shown that this initial transient growth near the leading edge can be possibly explained by the transient growth theory. Additionally, cooling the surface will increase the growth. By adding inhomogeneous boundary conditions or random roughness on the surface can strongly increase the magnitude of growth.

Dong, Haibo

110

The dark Z' portal: direct, indirect and collider searches  

NASA Astrophysics Data System (ADS)

We perform a detailed study of the dark Z' portal using a generic parametrization of the Z'-quarks couplings, both for light (8-15) GeV and heavy (100-1000) GeV dark matter scenarios. We present a comprehensive study of the collider phenomenology including jet clustering, hadronization, and detector artifacts, which allows us to derive accurate bounds from the search for new resonances in dijet events and from mono-jet events in the LHC 7 TeV, LHC 8 TeV, and Tevatron 1.96 TeV data. We also compute the dark matter relic abundance, the relevant scattering cross sections and pair-annihilation spectrum, and compare our results with the current PLANCK, Fermi-LAT and XENON100/LUX bounds. Lastly, we highlight the importance of complementary searches for dark matter, and outline the excluded versus still viable parameter space regions of the dark Z' portal.

Alves, Alexandre; Profumo, Stefano; Queiroz, Farinaldo S.

2014-04-01

111

Micromegas ?TPC for direct Dark Matter search with MIMAC  

NASA Astrophysics Data System (ADS)

The MIMAC project is a multi-chamber detector for Dark Matter search, aiming at measuring both track and ionization with a matrix of micromegas ?TPC filled with 3He and CF4. Recent experimental results on the first measurements of the Helium quenching factor at low energy (1 keV recoil) are presented, together with the first simulation of the track reconstruction. Recontruction of tack of ? from Radon impurities is shown as a first proof of concept.

Mayet, F.; Guillaudin, O.; Grignon, C.; Koumeir, C.; Santos, D.; Colas, P.; Giomataris, I.

2009-07-01

112

PANMIN: sequential and parallel global optimization procedures with a variety of options for the local search strategy  

NASA Astrophysics Data System (ADS)

We present two sequential and one parallel global optimization codes, that belong to the stochastic class, and an interface routine that enables the use of the Merlin/MCL environment as a non-interactive local optimizer. This interface proved extremely important, since it provides flexibility, effectiveness and robustness to the local search task that is in turn employed by the global procedures. We demonstrate the use of the parallel code to a molecular conformation problem. Program summaryTitle of program: PANMIN Catalogue identifier: ADSU Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSU Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer for which the program is designed and others on which it has been tested: PANMIN is designed for UNIX machines. The parallel code runs on either shared memory architectures or on a distributed system. The code has been tested on a SUN Microsystems ENTERPRISE 450 with four CPUs, and on a 48-node cluster under Linux, with both the GNU g77 and the Portland group compilers. The parallel implementation is based on MPI and has been tested with LAM MPI and MPICH Installation: University of Ioannina, Greece Programming language used: Fortran-77 Memory required to execute with typical data: Approximately O( n2) words, where n is the number of variables No. of bits in a word: 64 No. of processors used: 1 or many Has the code been vectorised or parallelized?: Parallelized using MPI No. of bytes in distributed program, including test data, etc.: 147163 No. of lines in distributed program, including the test data, etc.: 14366 Distribution format: gzipped tar file Nature of physical problem: A multitude of problems in science and engineering are often reduced to minimizing a function of many variables. There are instances that a local optimum does not correspond to the desired physical solution and hence the search for a better solution is required. Local optimization techniques can be trapped in any local minimum. Global Optimization is then the appropriate tool. For example, solving a non-linear system of equations via optimization, one may encounter many local minima that do not correspond to solutions, i.e. they are far from zero Method of solution: PANMIN is a suite of programs for Global Optimization that take advantage of the Merlin/MCL optimization environment [1,2]. We offer implementations of two algorithms that belong to the stochastic class and use local searches either as intermediate steps or as solution refinement Restrictions on the complexity of the problem: The only restriction is set by the available memory of the hardware configuration. The software can handle bound constrained problems. The Merlin Optimization environment must be installed. Availability of an MPI installation is necessary for executing the parallel code Typical running time: Depending on the objective function References: [1] D.G. Papageorgiou, I.N. Demetropoulos, I.E. Lagaris, Merlin-3.0. A multidimensional optimization environment, Comput. Phys. Commun. 109 (1998) 227-249. [2] D.G. Papageorgiou, I.N. Demetropoulos, I.E. Lagaris, The Merlin Control Language for strategic optimization, Comput. Phys. Commun. 109 (1998) 250-275.

Theos, F. V.; Lagaris, I. E.; Papageorgiou, D. G.

2004-05-01

113

Current Results and Future Directions of the Pulsar Search Collaboratory  

NASA Astrophysics Data System (ADS)

The Pulsar Search Collaboratory (PSC) is a joint partnership between the National Radio Astronomy Observatory (NRAO) and West Virginia University (WVU). The ultimate goal of the PSC is to interest students in science, technology, engineering, mathematics (STEM) fields by engaging them in conducting authentic scientific research-specifically the search for new pulsars. Of the 33 schools in the original PSC program, 13 come from rural school districts; one third of these are from schools where over 50% participate in the Free/Reduced School Lunch program. We are reaching first generation college-goers. For students, the program succeeds in building confidence in students, rapport with the scientists involved in the project, and greater comfort with team-work. We see additional gains in girls, as they see themselves more as scientists after participating in the PSC program, which is an important predictor of success in STEM fields. The PSC has had several scientific successes as well. To date, PSC students have made two astronomical discoveries: a 4.8-s pulsar and bright radio burst of astrophysical origin, most likely from a sporadic neutron star. We will report on the status of the project including new evaluation data. We will also describe PSC-West, an experiment to involve schools in Illinois and Wisconsin using primarily online tools for professional development of teachers and coaching of students. Knowledge gained through our efforts with PSC-West will assist the PSC team in scaling up the project.

Heatherly, Sue Ann; Rosen, R.; McLaughlin, M.; Lorimer, D.

2011-01-01

114

Large-scale parallel arrays of silicon nanowires via block copolymer directed self-assembly  

NASA Astrophysics Data System (ADS)

Extending the resolution and spatial proximity of lithographic patterning below critical dimensions of 20 nm remains a key challenge with very-large-scale integration, especially if the persistent scaling of silicon electronic devices is sustained. One approach, which relies upon the directed self-assembly of block copolymers by chemical-epitaxy, is capable of achieving high density 1 : 1 patterning with critical dimensions approaching 5 nm. Herein, we outline an integration-favourable strategy for fabricating high areal density arrays of aligned silicon nanowires by directed self-assembly of a PS-b-PMMA block copolymer nanopatterns with a L0 (pitch) of 42 nm, on chemically pre-patterned surfaces. Parallel arrays (5 × 106 wires per cm) of uni-directional and isolated silicon nanowires on insulator substrates with critical dimension ranging from 15 to 19 nm were fabricated by using precision plasma etch processes; with each stage monitored by electron microscopy. This step-by-step approach provides detailed information on interfacial oxide formation at the device silicon layer, the polystyrene profile during plasma etching, final critical dimension uniformity and line edge roughness variation nanowire during processing. The resulting silicon-nanowire array devices exhibit Schottky-type behaviour and a clear field-effect. The measured values for resistivity and specific contact resistance were ((2.6 +/- 1.2) × 105 ?cm) and ((240 +/- 80) ?cm2) respectively. These values are typical for intrinsic (un-doped) silicon when contacted by high work function metal albeit counterintuitive as the resistivity of the starting wafer (~10 ?cm) is 4 orders of magnitude lower. In essence, the nanowires are so small and consist of so few atoms, that statistically, at the original doping level each nanowire contains less than a single dopant atom and consequently exhibits the electrical behaviour of the un-doped host material. Moreover this indicates that the processing successfully avoided unintentional doping. Therefore our approach permits tuning of the device steps to contact the nanowires functionality through careful selection of the initial bulk starting material and/or by means of post processing steps e.g. thermal annealing of metal contacts to produce high performance devices. We envision that such a controllable process, combined with the precision patterning of the aligned block copolymer nanopatterns, could prolong the scaling of nanoelectronics and potentially enable the fabrication of dense, parallel arrays of multi-gate field effect transistors.Extending the resolution and spatial proximity of lithographic patterning below critical dimensions of 20 nm remains a key challenge with very-large-scale integration, especially if the persistent scaling of silicon electronic devices is sustained. One approach, which relies upon the directed self-assembly of block copolymers by chemical-epitaxy, is capable of achieving high density 1 : 1 patterning with critical dimensions approaching 5 nm. Herein, we outline an integration-favourable strategy for fabricating high areal density arrays of aligned silicon nanowires by directed self-assembly of a PS-b-PMMA block copolymer nanopatterns with a L0 (pitch) of 42 nm, on chemically pre-patterned surfaces. Parallel arrays (5 × 106 wires per cm) of uni-directional and isolated silicon nanowires on insulator substrates with critical dimension ranging from 15 to 19 nm were fabricated by using precision plasma etch processes; with each stage monitored by electron microscopy. This step-by-step approach provides detailed information on interfacial oxide formation at the device silicon layer, the polystyrene profile during plasma etching, final critical dimension uniformity and line edge roughness variation nanowire during processing. The resulting silicon-nanowire array devices exhibit Schottky-type behaviour and a clear field-effect. The measured values for resistivity and specific contact resistance were ((2.6 +/- 1.2) × 105 ?cm) and ((240 +/- 80) ?cm2) respectively. These values are typic

Farrell, Richard A.; Kinahan, Niall T.; Hansel, Stefan; Stuen, Karl O.; Petkov, Nikolay; Shaw, Matthew T.; West, Laetitia E.; Djara, Vladimir; Dunne, Robert J.; Varona, Olga G.; Gleeson, Peter G.; Jung, Soon-Jung; Kim, Hye-Young; Kole?nik, Maria M.; Lutz, Tarek; Murray, Christopher P.; Holmes, Justin D.; Nealey, Paul F.; Duesberg, Georg S.; Krsti?, Vojislav; Morris, Michael A.

2012-05-01

115

A Search for Lyman Break Galaxies at z>8 in the NICMOS Parallel Imaging Survey  

Microsoft Academic Search

We have selected 14 J-dropout Lyman break galaxy (LBG) candidates with J110-H160>=2.5 from the NICMOS Parallel Imaging Survey. This survey consists of 135 arcmin2 of imaging in 228 independent sight lines, reaching average 5 sigma sensitivities of J110=25.8 and H160=25.6 (AB). Distinguishing these candidates from dust-reddened star-forming galaxies at z~2-3 is difficult and will require longer wavelength observations. We consider

Alaina L. Henry; Matthew A. Malkan; James W. Colbert; Brian Siana; Harry I. Teplitz; Patrick McCarthy; Lin Yan

2007-01-01

116

Experimental Studies of the Interaction Between a Parallel Shear Flow and a Directionally-Solidifying Front  

NASA Technical Reports Server (NTRS)

It has long been recognized that flow in the melt can have a profound influence on the dynamics of a solidifying interface and hence the quality of the solid material. In particular, flow affects the heat and mass transfer, and causes spatial and temporal variations in the flow and melt composition. This results in a crystal with nonuniform physical properties. Flow can be generated by buoyancy, expansion or contraction upon phase change, and thermo-soluto capillary effects. In general, these flows can not be avoided and can have an adverse effect on the stability of the crystal structures. This motivates crystal growth experiments in a microgravity environment, where buoyancy-driven convection is significantly suppressed. However, transient accelerations (g-jitter) caused by the acceleration of the spacecraft can affect the melt, while convection generated from the effects other than buoyancy remain important. Rather than bemoan the presence of convection as a source of interfacial instability, Hurle in the 1960s suggested that flow in the melt, either forced or natural convection, might be used to stabilize the interface. Delves considered the imposition of both a parabolic velocity profile and a Blasius boundary layer flow over the interface. He concluded that fast stirring could stabilize the interface to perturbations whose wave vector is in the direction of the fluid velocity. Forth and Wheeler considered the effect of the asymptotic suction boundary layer profile. They showed that the effect of the shear flow was to generate travelling waves parallel to the flow with a speed proportional to the Reynolds number. There have been few quantitative, experimental works reporting on the coupling effect of fluid flow and morphological instabilities. Huang studied plane Couette flow over cells and dendrites. It was found that this flow could greatly enhance the planar stability and even induce the cell-planar transition. A rotating impeller was buried inside the sample cell, driven by an outside rotating magnet, in order to generate the flow. However, it appears that this was not a well-controlled flow and may also have been unsteady. In the present experimental study, we want to study how a forced parallel shear flow in a Hele-Shaw cell interacts with the directionally solidifying crystal interface. The comparison of experimental data show that the parallel shear flow in a Hele-Shaw cell has a strong stabilizing effect on the planar interface by damping the existing initial perturbations. The flow also shows a stabilizing effect on the cellular interface by slightly reducing the exponential growth rate of cells. The left-right symmetry of cells is broken by the flow with cells tilting toward the incoming flow direction. The tilting angle increases with the velocity ratio. The experimental results are explained through the parallel flow effect on lateral solute transport. The phenomenon of cells tilting against the flow is consistent with the numerical result of Dantzig and Chao.

Zhang, Meng; Maxworthy, Tony

1999-01-01

117

An Introduction to Dark Matter Direct Detection Searches & Techniques  

NASA Astrophysics Data System (ADS)

Weakly Interacting Massive Particles (WIMPs), are a leading candidate for the dark matter that is observed to constitute ˜25% of the total mass-energy density of the Universe. The direct detection of relic WIMPs (those produced during the early moments of the Universe's expansion) is at the forefront of active research areas in particle astrophysics with a numerous international experimental collaborations pursuing this goal. This paper presents an overview of the theoretical and practical considerations common to the design and operation of direct detection experiments, as well as their unique features and capabilities.

Saab, T.

2013-12-01

118

The DRIFT project: searching for WIMPs with a directional detector  

Microsoft Academic Search

A low pressure time projection chamber for the detection of WIMPs is discussed. Discrimination against Compton electron background in such a device should be very good, and directional information about the recoil atoms would be obtainable. If a full 3-D reconstruction of the recoil tracks can be achieved, Monte Carlo studies indicate that a WIMP signal could be identified with

M. J. Lehner; K. Griest; C. J. Martoff; G. E. Masek; T. Ohnuki; D. Snowden-Ifft; N. J. C. Spooner

1999-01-01

119

Large-scale parallel arrays of silicon nanowires via block copolymer directed self-assembly.  

PubMed

Extending the resolution and spatial proximity of lithographic patterning below critical dimensions of 20 nm remains a key challenge with very-large-scale integration, especially if the persistent scaling of silicon electronic devices is sustained. One approach, which relies upon the directed self-assembly of block copolymers by chemical-epitaxy, is capable of achieving high density 1?:?1 patterning with critical dimensions approaching 5 nm. Herein, we outline an integration-favourable strategy for fabricating high areal density arrays of aligned silicon nanowires by directed self-assembly of a PS-b-PMMA block copolymer nanopatterns with a L(0) (pitch) of 42 nm, on chemically pre-patterned surfaces. Parallel arrays (5 × 10(6) wires per cm) of uni-directional and isolated silicon nanowires on insulator substrates with critical dimension ranging from 15 to 19 nm were fabricated by using precision plasma etch processes; with each stage monitored by electron microscopy. This step-by-step approach provides detailed information on interfacial oxide formation at the device silicon layer, the polystyrene profile during plasma etching, final critical dimension uniformity and line edge roughness variation nanowire during processing. The resulting silicon-nanowire array devices exhibit Schottky-type behaviour and a clear field-effect. The measured values for resistivity and specific contact resistance were ((2.6 ± 1.2) × 10(5)?cm) and ((240 ± 80) ?cm(2)) respectively. These values are typical for intrinsic (un-doped) silicon when contacted by high work function metal albeit counterintuitive as the resistivity of the starting wafer (?10 ?cm) is 4 orders of magnitude lower. In essence, the nanowires are so small and consist of so few atoms, that statistically, at the original doping level each nanowire contains less than a single dopant atom and consequently exhibits the electrical behaviour of the un-doped host material. Moreover this indicates that the processing successfully avoided unintentional doping. Therefore our approach permits tuning of the device steps to contact the nanowires functionality through careful selection of the initial bulk starting material and/or by means of post processing steps e.g. thermal annealing of metal contacts to produce high performance devices. We envision that such a controllable process, combined with the precision patterning of the aligned block copolymer nanopatterns, could prolong the scaling of nanoelectronics and potentially enable the fabrication of dense, parallel arrays of multi-gate field effect transistors. PMID:22481430

Farrell, Richard A; Kinahan, Niall T; Hansel, Stefan; Stuen, Karl O; Petkov, Nikolay; Shaw, Matthew T; West, Laetitia E; Djara, Vladimir; Dunne, Robert J; Varona, Olga G; Gleeson, Peter G; Jung, Soon-Jung; Kim, Hye-Young; Kole?nik, Maria M; Lutz, Tarek; Murray, Christopher P; Holmes, Justin D; Nealey, Paul F; Duesberg, Georg S; Krsti?, Vojislav; Morris, Michael A

2012-05-21

120

A parallel direct numerical simulation of dust particles in a turbulent flow  

NASA Astrophysics Data System (ADS)

Due to their effects on radiation transport, aerosols play an important role in the global climate. Mineral dust aerosol is a predominant natural aerosol in the desert and semi-desert regions of the Middle East and North Africa (MENA). The Arabian Peninsula is one of the three predominant source regions on the planet "exporting" dust to almost the entire world. Mineral dust aerosols make up about 50% of the tropospheric aerosol mass and therefore produces a significant impact on the Earth's climate and the atmospheric environment, especially in the MENA region that is characterized by frequent dust storms and large aerosol generation. Understanding the mechanisms of dust emission, transport and deposition is therefore essential for correctly representing dust in numerical climate prediction. In this study we present results of numerical simulations of dust particles in a turbulent flow to study the interaction between dust and the atmosphere. Homogenous and passive dust particles in the boundary layers are entrained and advected under the influence of a turbulent flow. Currently no interactions between particles are included. Turbulence is resolved through direct numerical simulation using a parallel incompressible Navier-Stokes flow solver. Model output provides information on particle trajectories, turbulent transport of dust and effects of gravity on dust motion, which will be used to compare with the wind tunnel experiments at University of Texas at Austin. Results of testing of parallel efficiency and scalability is provided. Future versions of the model will include air-particle momentum exchanges, varying particle sizes and saltation effect. The results will be used for interpreting wind tunnel and field experiments and for improvement of dust generation parameterizations in meteorological models.

Nguyen, H. V.; Yokota, R.; Stenchikov, G.; Kocurek, G.

2012-04-01

121

The Great Beyond: Higher Dimensions, Parallel Universes and the Extraordinary Search for a Theory of Everything  

NASA Astrophysics Data System (ADS)

Praise for The Great Beyond "A marvelous book-very clear, very readable. A brilliant introduction to the math and physics of higher dimensions, from Flatland to superstrings. Its greatest strength is a wealth of fascinating historical narrative and anecdote. I enjoyed it enormously." -Ian Stewart, author of Flatterland "A remarkable journey from Plato's cave to the farthest reaches of human thought and scientific knowledge. This mind-boggling book allows readers to dream strange visions of hyperspace, chase light waves, explore Klein's quantum odyssey and Kaluza's cocoon, leap through parallel universes, and grasp the very essence of conscience and cosmos. Buy this book and feed your head." -Clifford Pickover, author of A Passion for Mathematics "Halpern looks with a bemused eye at the wildest ideas currently afoot in physics. He takes us into the personal world of those who relish and explore seemingly outlandish notions, and does it with a light, engaging style." -Gregory Benford, author of Foundation's Fear "An informative, stimulating, and thoughtful presentation at the very frontiers of contemporary physics. It is quite on a par with Brian Greene's The Elegant Universe or his more recent The Fabric of the Cosmos, and as such, deserves to receive wide non-specialist coverage among an intelligent, curious, thinking public." -Professor E. Sheldon, Contemporary Physics

Halpern, Paul

2005-08-01

122

Spiral search: a hydrophobic-core directed local search for simplified PSP on 3D FCC lattice  

PubMed Central

Background Protein structure prediction is an important but unsolved problem in biological science. Predicted structures vary much with energy functions and structure-mapping spaces. In our simplified ab initio protein structure prediction methods, we use hydrophobic-polar (HP) energy model for structure evaluation, and 3-dimensional face-centred-cubic lattice for structure mapping. For HP energy model, developing a compact hydrophobic-core (H-core) is essential for the progress of the search. The H-core helps find a stable structure with the lowest possible free energy. Results In order to build H-cores, we present a new Spiral Search algorithm based on tabu-guided local search. Our algorithm uses a novel H-core directed guidance heuristic that squeezes the structure around a dynamic hydrophobic-core centre. We applied random walks to break premature H-cores and thus to avoid early convergence. We also used a novel relay-restart technique to handle stagnation. Conclusions We have tested our algorithms on a set of benchmark protein sequences. The experimental results show that our spiral search algorithm outperforms the state-of-the-art local search algorithms for simplified protein structure prediction. We also experimentally show the effectiveness of the relay-restart.

2013-01-01

123

Design and characterization of harmonic diffractive microlens arrays with continuous relief for parallel laser direct writing  

NASA Astrophysics Data System (ADS)

To make the real-time focusing possible in the exposure process, diffractive microlens arrays with continuous relief are designed and fabricated using harmonic diffraction theory for parallel laser direct writing to integrate the exposing and autofocusing functions in one array by taking both the writing resolution and diffraction efficiency into consideration. A theoretical model is established using Rayleigh-Sommerfeld diffraction theory to accurately characterize the focusing characteristics of each harmonic diffractive microlens in the array so that the fidelity of pattern can be improved through exposure dose modulation. The measurements made indicate that the experimental results coincide well with the theoretical results when the writing laser with a wavelength of 441.6 nm and the autofocusing laser with a wavelength of 670 nm are normally incident on an array with an F-number of F/4 fabricated on fused silica, and the array developed can be used to synchronously focus the writing laser and the autofocusing laser into the same spot of the array.

Shan, Mingguang; Guo, Lili; Zhong, Zhi

2010-03-01

124

Astrophysical motivation for directed searches for a stochastic gravitational wave background  

NASA Astrophysics Data System (ADS)

The nearby Universe is expected to create an anisotropic stochastic gravitational-wave background (SGWB). Different algorithms have been developed and implemented to search for isotropic and anisotropic SGWBs. The aim of this paper is to quantify the advantage of an optimal anisotropic search, specifically comparing a point source with an isotropic background. Clusters of galaxies appear as point sources to a network of ground-based laser-interferometric detectors. The optimal search strategy for these sources is a "directed radiometer search." We show that the flux of SGWBs created by the millisecond pulsars in the Virgo cluster produces a significantly stronger signal than the nearly isotropic background of unresolved sources of the same kind. We compute their strain power spectra for different cosmologies and the distribution of populations over redshifts. We conclude that a localized source, like the Virgo cluster, can be resolved from the isotropic background with very high significance using the directed-search algorithm. For backgrounds dominated by nearby sources, up to a redshift of about 3, we show that the directed search for a localized source can have a signal-to-noise ratio that is greater than that for the all-sky integrated isotropic search.

Mazumder, Nairwita; Mitra, Sanjit; Dhurandhar, Sanjeev

2014-04-01

125

Directed intermittent search for a hidden target on a dendritic tree  

NASA Astrophysics Data System (ADS)

Motivated by experimental observations of active (motor-driven) intracellular transport in neuronal dendrites, we analyze a stochastic model of directed intermittent search on a tree network. A particle injected from the cell body or soma into the primary branch of the dendritic tree randomly switches between a stationary search phase and a mobile nonsearch phase that is biased in the forward direction. A (synaptic) target is presented somewhere within the tree, which the particle can locate if it is within a certain range and in the searching phase. We approximate the moment generating function using Green’s function methods. The moment generating function is then used to compute the hitting probability and conditional mean first passage time to the target. We show that in contrast to a previously explored finite interval case, there is a range of parameters for which a bidirectional search strategy is more efficient than a unidirectional one in finding the target.

Newby, Jay M.; Bressloff, Paul C.

2009-08-01

126

Parallelizing constraint programs  

Microsoft Academic Search

The availability of commodity multicore and multiprocessor machines and the inherent parallelism in constraint programming search offer significant opportunities for constraint programming. Both constraint-based local search and finite-domain techniques can dramatically benefit from parallelization. Yet, currently available libraries and languages offer very limited support to exploit the inherent parallelism and the high human cost incurred to develop parallel solutions confine

Laurent D. Michel

2010-01-01

127

Twin Similarities in Holland Types as Shown by Scores on the Self-Directed Search  

ERIC Educational Resources Information Center

This study examined the degree of similarity between scores on the Self-Directed Search from one set of identical twins. Predictably, a high congruence score was found. Results from a biographical sheet are discussed as well as implications of the results for career counselors.

Chauvin, Ida; McDaniel, Janelle R.; Miller, Mark J.; King, James M.; Eddlemon, Ondie L. M.

2012-01-01

128

Effects of the Self-Directed Search on High School Students  

ERIC Educational Resources Information Center

This study compares effects on high school students (N=959) of the Self Directed Search (SDS), the Vocational Preference Inventory (VPI), and no treatment. Students taking the SDS or the VPI evaluated the instruments, felt more satisfied with current occupational choices, and considered more occupational alternatives. Differences between the…

Zener, Thelma Baldwin; Schnuelle, Leslie

1976-01-01

129

An Evaluation of the Self-Directed Search: A Guide to Educational and Vocational Planning.  

ERIC Educational Resources Information Center

In an evaluation of the Self-Directed Search (SDS), a self-administered vocational counseling experience based on Holland's theory of vocational choice and his occupational classification, a total of 1,092 students in 10th, 11th, and 12th grades in four high schools were divided into three treatment groups. One group took the regular, published…

Zener, Thelma Baldwin; Schnuelle, Leslie

130

Direct Searches for New Physics at the e+-e- B-Factories.  

National Technical Information Service (NTIS)

B-Factories are versatile machines which physics output shed light on many aspects of high precision physics in the last decade. In the following we will report about the most recent results in direct searches for new physics performed by BaBar and Belle ...

A. Cervelli

2010-01-01

131

Congruency between Occupational Daydreams and Self Directed Search (SDS) Scores among College Students  

ERIC Educational Resources Information Center

In this study, the relationship of expressed occupational daydreams and scores on the Self-Directed Search (SDS) were examined. Results were consistent with Holland's theory of careers. Implications for career counselors are discussed. Students were asked to provide specific biographical data (i. e., age, gender, race) and to write down their…

Miller, Mark J.; Springer, Thomas P.; Tobacyk, Jerome; Wells, Don

2004-01-01

132

Using the Self-Directed Search: Career Explorer with High-Risk Middle School Students  

ERIC Educational Resources Information Center

The Self-Directed Search: Career Explorer was used with 98 (95% African American) high-risk middle school students as part of 14 structured career groups based on Cognitive Information Processing theory. Results and implications are presented on the outcomes of this program.

Osborn, Debra S.; Reardon, Robert C.

2006-01-01

133

Computer versus Counselor Interpretation of Interest Inventories: The Case of the Self-Directed Search.  

ERIC Educational Resources Information Center

Examined interpretations of 100 career counselee's responses to Self-Directed Search (SDS). Found that agreement between scales identified as relevant was as high as agreement among counselors, insignificant correlations between counselors' judgments of counselee's degree of interest crystallization and Holland's (1985) measure of consistency, and…

Gati, Itamar; Blumberg, Dani

1991-01-01

134

Design of directional antenna for cell phone detector for post disaster search and rescue  

Microsoft Academic Search

A modified double rhombus antenna is designed to detect cell phones for post disaster search and rescue operations. The antenna consists of two rhombus shape dipoles with different size fed by microstrip line with a truncated ground plane which acts as reflector to produce end fire radiation. It was found that the directivity of the antenna depends mainly on the

Abdelnasser A. Eldek; K. S. Ali; Fatma EI-Hefnawi

2009-01-01

135

Interpreting Self-Directed Search Profiles: Validity of the "Rule of Eight"  

ERIC Educational Resources Information Center

Based on the standard error of measurement, Holland (1985) suggested the "rule of eight" for determining the meaningfulness of differences between two summary scores on the Self Directed Search. The present study empirically examined the rule's validity for practice. The participants were 2397 (1497 females and 900 males) undergraduate students…

Glavin, Kevin W.; Savickas, Mark L.

2011-01-01

136

Wavefront Synthesis and Reconstruction: Direct Binary Search Holograms and Synthetic Aperture Radar  

Microsoft Academic Search

Computer-generated binary holograms can perform complex waveshaping functions that are beyond the capability of ordinary refractive optical elements. An iterative procedure for the synthesis of computer-generated holograms (CGH's) is investigated that consists of a direct binary search (DBS) for the element configuration that minimizes the error between the actual and desired reconstructed wavefronts. Although DBS CGH's have low reconstruction error

Brian Keith Jennison

1990-01-01

137

Scalability of Parallel Spatial Direct Numerical Simulations on Intel Hypercube and IBM SP1 and SP2  

NASA Technical Reports Server (NTRS)

The implementation and performance of a parallel spatial direct numerical simulation (PSDNS) approach on the Intel iPSC/860 hypercube and IBM SP1 and SP2 parallel computers is documented. Spatially evolving disturbances associated with the laminar-to-turbulent transition in boundary-layer flows are computed with the PSDNS code. The feasibility of using the PSDNS to perform transition studies on these computers is examined. The results indicate that PSDNS approach can effectively be parallelized on a distributed-memory parallel machine by remapping the distributed data structure during the course of the calculation. Scalability information is provided to estimate computational costs to match the actual costs relative to changes in the number of grid points. By increasing the number of processors, slower than linear speedups are achieved with optimized (machine-dependent library) routines. This slower than linear speedup results because the computational cost is dominated by FFT routine, which yields less than ideal speedups. By using appropriate compile options and optimized library routines on the SP1, the serial code achieves 52-56 M ops on a single node of the SP1 (45 percent of theoretical peak performance). The actual performance of the PSDNS code on the SP1 is evaluated with a "real world" simulation that consists of 1.7 million grid points. One time step of this simulation is calculated on eight nodes of the SP1 in the same time as required by a Cray Y/MP supercomputer. For the same simulation, 32-nodes of the SP1 and SP2 are required to reach the performance of a Cray C-90. A 32 node SP1 (SP2) configuration is 2.9 (4.6) times faster than a Cray Y/MP for this simulation, while the hypercube is roughly 2 times slower than the Y/MP for this application. KEY WORDS: Spatial direct numerical simulations; incompressible viscous flows; spectral methods; finite differences; parallel computing.

Joslin, Ronald D.; Hanebutte, Ulf R.; Zubair, Mohammad

1995-01-01

138

Serial and parallel Si, Ge, and SiGe direct-write with scanning probes and conducting stamps  

SciTech Connect

Precise materials integration in nanostructures is fundamental for future electronic and photonic devices. We demonstrate Si, Ge, and SiGe nanostructure direct-write with deterministic size, geometry, and placement control. The biased probe of an atomic force microscope (AFM) reacts diphenylsilane or diphenylgermane to direct-write carbon-free Si, Ge, and SiGe nano and heterostructures. Parallel directwrite is available on large areas by substituting the AFM probe with conducting microstructured stamps. This facile strategy can be easily expanded to a broad variety of semiconductor materials through precursor selection.

Vasko, Stephanie E.; Kapetanovic, Adnan; Talla, Vamsi; Brasino, Michael D.; Zhu, Zihua; Scholl, Andreas; Torrey, Jessica D.; Rolandi, Marco

2011-05-16

139

Do cataclastic deformation bands form parallel to lines of no finite elongation (LNFE) or zero extension directions?  

NASA Astrophysics Data System (ADS)

Conjugate cataclastic deformation bands cut unconsolidated sand and gravel at McKinleyville, California, and dip shallowly towards the north-northeast and south-southwest. The acute dihedral angle between the two sets of deformation bands is 47° and is bisected by the sub-horizontal, north-northeast directed incremental and finite shortening directions. Trishear models of fault propagation folding above the McKinleyville fault predict two sets of LNFE (lines of no finite elongation) that plunge steeply and shallowly to the south and north. These predictions are inconsistent with deformation band orientations and suggest that deformation bands did not form parallel to these LNFE. During plane strain, zero extension directions with acute dihedral angles of 47° develop when the dilatancy rate (dV/d?1) is -4.3. Experimental dilatancy rates for Vosges sandstone (cohesion > 0) and unconsolidated Hostun sand suggest the deformation bands either developed parallel to zero extension directions or in accordance with the Mohr-Coulomb criterion, assuming initial porosities of 22% and 39%, respectively. An empirical relationship between dV/d?1, relative density and mean stress suggests that dilatancy rates for Vosges sandstone overestimate dV/d?1 at McKinleyville. Deformation bands at McKinleyville likely developed either in a Mohr-Coulomb orientation, or an intermediate orientation bounded by the Mohr-Coulomb (?C) and Roscoe (?R) angles.

Imber, Jonathan; Perry, Tom; Jones, Richard R.; Wightman, Ruth H.

2012-12-01

140

Search Learning and the Direction of R&D Following the Pheromone Trail  

Microsoft Academic Search

Abstract Although the economic literature on R&D is very broad, the question of direction in R&D investment, which is obvious ly of great importance, has been scarcely analyzed.This paper interprets R&D as search problem,in an unknown,technological environment. Inspiration for some,of the modeling,ideas in addressing this problem is found in t he behavior of foraging ants. It is within this context

Roy Shalem

141

ArDM: a ton-scale LAr detector for direct Dark Matter searches  

Microsoft Academic Search

The Argon Dark Matter (ArDM-1t) experiment is a ton-scale liquid argon (LAr)\\u000adouble-phase time projection chamber designed for direct Dark Matter searches.\\u000aSuch a device allows to explore the low energy frontier in LAr with a charge\\u000aimaging detector. The ionization charge is extracted from the liquid into the\\u000agas phase and there amplified by the use of a Large

A. Marchionni; C. Amsler; A. Badertscher; V. Boccone; A. Bueno; M. C. Carmona-Benitez; J. Coleman; W. Creus; A. Curioni; M. Daniel; E. J. Dawe; U. Degunda; A. Gendotti; L. Epprecht; S. Horikawa; L. Kaufmann; L. Knecht; M. Laffranchi; C. Lazzaro; P. K. Lightfoot; D. Lussi; J. Lozano; K. Mavrokoridis; A. Melgarejo; P. Mijakowski; G. Natterer; S. Navas-Concha; P. Otyugova; M. de Prado; P. Przewlocki; C. Regenfus; F. Resnati; M. Robinson; J. Rochet; L. Romero; E. Rondio; A. Rubbia; L. Scotto-Lavina; N. J. C. Spooner; T. Strauss; C. Touramanis; J. Ulbricht; T. Viant

2010-01-01

142

ArDM: a ton-scale LAr detector for direct Dark Matter searches  

Microsoft Academic Search

The Argon Dark Matter (ArDM-1t) experiment is a ton-scale liquid argon (LAr) double-phase time projection chamber designed for direct Dark Matter searches. Such a device allows to explore the low energy frontier in LAr with a charge imaging detector. The ionization charge is extracted from the liquid into the gas phase and there amplified by the use of a Large

A. Marchionni; C. Amsler; A. Badertscher; V. Boccone; A. Bueno; M. C. Carmona-Benitez; J. Coleman; W. Creus; A. Curioni; M. Daniel; E. J. Dawe; U. Degunda; A. Gendotti; L. Epprecht; S. Horikawa; L. Kaufmann; L. Knecht; M. Laffranchi; C. Lazzaro; P. K. Lightfoot; D. Lussi; J. Lozano; K. Mavrokoridis; A. Melgarejo; P. Mijakowski; G. Natterer; S. Navas-Concha; P. Otyugova; M. de Prado; P. Przewlocki; C. Regenfus; F. Resnati; M. Robinson; J. Rochet; L. Romero; E. Rondio; A. Rubbia; L. Scotto-Lavina; N. J. C. Spooner; T. Strauss; C. Touramanis; J. Ulbricht; T. Viant

2011-01-01

143

Search for Coincidences in Time and Arrival Direction of Auger Data with Astrophysical Transients  

SciTech Connect

The data collected by the Pierre Auger Observatory are analyzed to search for coincidences between the arrival directions of high-energy cosmic rays and the positions in the sky of astrophysical transients. Special attention is directed towards gamma ray observations recorded by NASA's Swift mission, which have an angular resolution similar to that of the Auger surface detectors. In particular, we check our data for evidence of a signal associated with the giant flare that came from the soft gamma repeater 1806-20 on December 27, 2004.

Anchordoqui, Luis; Collaboration, for the Pierre Auger

2007-06-01

144

Oscillation modes of direct current microdischarges with parallel-plate geometry  

SciTech Connect

Two different oscillation modes in microdischarge with parallel-plate geometry have been observed: relaxation oscillations with frequency range between 1.23 and 2.1 kHz and free-running oscillations with 7 kHz frequency. The oscillation modes are induced by increasing power supply voltage or discharge current. For a given power supply voltage, there is a spontaneous transition from one to other oscillation mode and vice versa. Before the transition from relaxation to free-running oscillations, the spontaneous increase of oscillation frequency of relaxation oscillations form 1.3 kHz to 2.1 kHz is measured. Fourier transform spectra of relaxation oscillations reveal chaotic behavior of microdischarges. Volt-ampere (V-A) characteristics associated with relaxation oscillations describes periodical transition between low current, diffuse discharge, and normal glow. However, free-running oscillations appear in subnormal glow only.

Stefanovic, Ilija; Kuschel, Thomas; Winter, Joerg [Institut fuer Experimentalphysik II, Ruhr-Universitaet Bochum, 44781 Bochum (Germany); Skoro, Nikola; Maric, Dragana; Petrovic, Zoran Lj [Institute of Physics, University of Belgrade, POB 68, 11080 Belgrade (Serbia)

2011-10-15

145

Chaining direct memory access data transfer operations for compute nodes in a parallel computer  

DOEpatents

Methods, systems, and products are disclosed for chaining DMA data transfer operations for compute nodes in a parallel computer that include: receiving, by an origin DMA engine on an origin node in an origin injection FIFO buffer for the origin DMA engine, a RGET data descriptor specifying a DMA transfer operation data descriptor on the origin node and a second RGET data descriptor on the origin node, the second RGET data descriptor specifying a target RGET data descriptor on the target node, the target RGET data descriptor specifying an additional DMA transfer operation data descriptor on the origin node; creating, by the origin DMA engine, an RGET packet in dependence upon the RGET data descriptor, the RGET packet containing the DMA transfer operation data descriptor and the second RGET data descriptor; and transferring, by the origin DMA engine to a target DMA engine on the target node, the RGET packet.

Archer, Charles J. (Rochester, MN); Blocksome, Michael A. (Rochester, MN)

2010-09-28

146

Oscillation modes of direct current microdischarges with parallel-plate geometry  

NASA Astrophysics Data System (ADS)

Two different oscillation modes in microdischarge with parallel-plate geometry have been observed: relaxation oscillations with frequency range between 1.23 and 2.1 kHz and free-running oscillations with 7 kHz frequency. The oscillation modes are induced by increasing power supply voltage or discharge current. For a given power supply voltage, there is a spontaneous transition from one to other oscillation mode and vice versa. Before the transition from relaxation to free-running oscillations, the spontaneous increase of oscillation frequency of relaxation oscillations form 1.3 kHz to 2.1 kHz is measured. Fourier transform spectra of relaxation oscillations reveal chaotic behavior of microdischarges. Volt-ampere (V-A) characteristics associated with relaxation oscillations describes periodical transition between low current, diffuse discharge, and normal glow. However, free-running oscillations appear in subnormal glow only.

Stefanovi?, Ilija; Kuschel, Thomas; Škoro, Nikola; Mari?, Dragana; Petrovi?, Zoran Lj; Winter, Jörg

2011-10-01

147

A massively parallel hybrid scheme for direct numerical simulation of turbulent viscoelastic channel flow  

Microsoft Academic Search

This paper describes in detail a numerical scheme designed for direct numerical simulation (DNS) of turbulent drag reduction. The hybrid spatial scheme includes Fourier spectral accuracy in two directions and sixth-order compact finite differences for first and second-order wall-normal derivatives, while time marching can be up to fourth-order accurate. High-resolution and high-drag reduction viscoelastic DNS are made possible through domain

Laurent Thais; Andrés E. Tejada-Mart?´nez; Thomas B. Gatski; Gilmar Mompean

2011-01-01

148

Applicability of preparative overpressured layer chromatography and direct bioautography in search of antibacterial chamomile compounds.  

PubMed

In situ sample preparation and preparative overpressured layer chromatography (OPLC) fractionation on a 0.5 mm thick adsorbent layer of chamomile flower methanol extract prepurified by conventional gravitation accelerated column chromatography were applied in searching for bioactive components. Sample cleanup in situ on the adsorbent layer subsequent to sample application was performed using mobile phase flow in the opposite direction (the input and output of the eluent was exchanged). The antibacterial effect of the fractions obtained from the stepwise gradient OPLC separation with the flow in the normal direction was evaluated by direct bioautography against two Gram-negative bacteria: the luminescence gene tagged plant pathogenic Pseudomonas syringae pv. maculicola, and the naturally luminescent marine bacterium Vibrio fischeri. The fractions having strong activity were analyzed by SPME-GC/MS and HPLC/MS/MS. Mainly essential oil components, coumarins, flavonoids, phenolic acids, and fatty acids were tentatively identified in the fractions. PMID:24645496

Móricz, Agnes M; Ott, Péter G; Alberti, Agnes; Böszörményi, Andrea; Lemberkovics, Eva; Szoke, Eva; Kéry, Agnes; Mincsovics, Emil

2013-01-01

149

Feedback-controlled parallel point process filter for estimation of goal-directed movements from neural signals.  

PubMed

Real-time brain-machine interfaces have estimated either the target of a movement, or its kinematics. However, both are encoded in the brain. Moreover, movements are often goal-directed and made to reach a target. Hence, modeling the goal-directed nature of movements and incorporating the target information in the kinematic decoder can increase its accuracy. Using an optimal feedback control design, we develop a recursive Bayesian kinematic decoder that models goal-directed movements and combines the target information with the neural spiking activity during movement. To do so, we build a prior goal-directed state-space model for the movement using an optimal feedback control model of the sensorimotor system that aims to emulate the processes underlying actual motor control and takes into account the sensory feedback. Most goal-directed models, however, depend on the movement duration, not known a priori to the decoder. This has prevented their real-time implementation. To resolve this duration uncertainty, the decoder discretizes the duration and consists of a bank of parallel point process filters, each combining the prior model of a discretized duration with the neural activity. The kinematics are computed by optimally combining these filter estimates. Using the feedback-controlled model and even a coarse discretization, the decoder significantly reduces the root mean square error in estimation of reaching movements performed by a monkey. PMID:23047892

Shanechi, Maryam M; Wornell, Gregory W; Williams, Ziv M; Brown, Emery N

2013-01-01

150

Computers: Massively parallel processors. (Latest citations from INSPEC the database for Physics, Electronics, and Computing). Published Search  

SciTech Connect

The bibliography contains citations concerning a concept in computers called Massively Parallel Processing. The processing power of a computer may be increased by using numerous processors in parallel and feeding data through a number of different computational paths at the same time. The citations explore these computers and their practical uses, and include case studies, specific problems solved, theory, and future possibilities and needs. Applications of neural network modeling, pattern recognition, image processing, local area routing, and genetic sequence comparison are discussed. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1993-10-01

151

Parallel mechanisms for direct and indirect membrane protein trafficking by synucleins  

PubMed Central

More than 2 decades of work have yet to conclusively determine the physiological role of the synuclein proteins, even though these abundant brain constituents are participants in a broad array of cellular processes. Among proposed physiological roles is a functional interaction between the synuclein proteins and monoamine transporters contributing to transporter trafficking through direct protein–protein interactions. Recent work shows that an antagonistic effect of the synuclein proteins on the secretory functions of the endoplasmic reticulum and the Golgi apparatus appears to simultaneously influence trafficking of the dopamine transporter and other membrane proteins. Here, we highlight these new findings in view of the broader literature identifying the role of synucleins in protein trafficking and suggest emerging themes for ongoing and future work in the field of synuclein biology.

Oaks, Adam W; Sidhu, Anita

2013-01-01

152

Cp Violation Studies with Babar (sin 2?, sin 2? and Direct Cpv Searches)  

NASA Astrophysics Data System (ADS)

We present the searches for direct CP violation in charmless two-body B decays, quasi two-body B decays and radiative penguin decays B ? K*?, using a sample of 22.7 million Bbar B events collected with the BABAR detector at the PEP-II collider. No evidence for direct CP violation is found and 90% confidence level limits are reported. A larger sample of 33 million Bbar B events is used for a measurement of time-dependent CP-violating asymmetries in neutral B mesons decays to several CP eigenstates. We measure sin 2? = 0.59 ± 0.14(stat) ± 0.05(syst), which constitutes an observation of CP violation in the B0 meson system at the 4.1? level. Results from a study of CP violation in the decay B0 to ?+?- are also presented.

T'jampens, S.

2003-02-01

153

Status and analysis system of directional dark matter search with nuclear emulsion  

NASA Astrophysics Data System (ADS)

We have been doing research and development for direct dark matter search by nuclear emulsion which is a solid state detector. This experiment enable directional detection of dark matter with the large mass target and model independent. Until now, we constructed a base of fully automatic analysis system and nuclear emulsion which can detect sub-micron tracks. We have demonstrated that it is possible to detect recoiled tracks of 100 nm or more by neutron irradiation. This track length is correspond to 37 keV in C(N,O) target. Additionally, we evaluated the angular resolution of the energy basis by using an ion implant system, and obtained 25 degrees or better resolution in 80 keV carbon ions. The fully automatic analysis system which can analyze very short tracks lead the experiment to next phase, we will do a quantitative study of the background toward gram scale test experiment at the Gran Sasso underground laboratory.

Katsuragawa, T.; Naka, T.; Asada, T.; Yoshimoto, M.; Hakamata, K.; Ishikawa, M.

2013-12-01

154

Simulations of particle acceleration in parallel shocks: Direct comparison between Monte Carlo and one-dimensional hybrid codes  

NASA Technical Reports Server (NTRS)

We have made a direct comparison between two different computer simulations of a plane, parallel, collisionless shock including particle acceleration to energies typical of those of diffuse ions observed at the earth bow shock. Despite the fact that the one-dimensional hybrid and Monte Carlo techniques employ entirely different algorithms, they give surprisingly close agreement in the overall shapes of the complete distribution functions for protons as well as heavier ions. Both methods show that energetic ions emerge smoothly from the background thermal plasma with approximately the same relative injection rate and that the fraction of the incoming plasma's energy flux that is converted into downstream enthalpy flux of the accelerated population (i.e., the acceleration efficiency) is similar in the two cases. The fraction of the downstream proton distribution made up of superthermal particles is quite large, with at least 10% of the energy flux going into protons with energies above 10 keV. In addition, an upstream precursor, produced by backstreaming energetic particles, is present in both shocks, although the Monte Carlo precursor is considerably longer than that produced in the hybrid shock. These results offer convincing evidence that, at least in these ways, the two simulations are consistent in their description of parallel shock structure and particle acceleration, and they lay the groundwork for development of shock models employing a combination of both methods.

Ellison, Donald C.; Giacalone, J.; Burgess, D.; Schwartz, S. J.

1993-01-01

155

Variationally localized search direction method for constrained optimization of non-orthogonal, localized orbitals in electronic structure calculations.  

PubMed

A new method for the constrained optimization of non-orthogonal, spatially localized orbitals using direct energy minimization techniques, in the context of electronic structure calculations, is presented. The variationally localized search direction (VLSD) method, as it was named, ensures that strict localization constraints are imposed upon the search direction vectors exactly, analytically and in a fully variational fashion. In contrast, the truncated search direction (TSD) method, of standard use in many electronic structure approaches with localization constraints, relies on the approximation that the truncated search direction vectors of the unconstrained problem resemble the exact search direction vectors of the constrained problem. With the TSD method, in order to maintain the localization constraints, a part of the pre-calculated information that is stored in the search direction vectors has to be deleted via an ad hoc, non-variational truncation step. The results on an extensive set of test molecules show that, in general, calculations with the VLSD method require less iterations to converge than with the TSD method for any size of the localization region. It was found that in calculations on certain systems where the TSD method is forced to delete a very large amount of information, the VLSD method is capable of achieving convergence in up to three times less iterations. Validation tests show that structural and electronic properties calculated with either method are accurate and in agreement with other electronic structure approaches. PMID:24182007

Ruiz-Serrano, Álvaro; Skylaris, Chris-Kriton

2013-10-28

156

Variationally localized search direction method for constrained optimization of non-orthogonal, localized orbitals in electronic structure calculations  

NASA Astrophysics Data System (ADS)

A new method for the constrained optimization of non-orthogonal, spatially localized orbitals using direct energy minimization techniques, in the context of electronic structure calculations, is presented. The variationally localized search direction (VLSD) method, as it was named, ensures that strict localization constraints are imposed upon the search direction vectors exactly, analytically and in a fully variational fashion. In contrast, the truncated search direction (TSD) method, of standard use in many electronic structure approaches with localization constraints, relies on the approximation that the truncated search direction vectors of the unconstrained problem resemble the exact search direction vectors of the constrained problem. With the TSD method, in order to maintain the localization constraints, a part of the pre-calculated information that is stored in the search direction vectors has to be deleted via an ad hoc, non-variational truncation step. The results on an extensive set of test molecules show that, in general, calculations with the VLSD method require less iterations to converge than with the TSD method for any size of the localization region. It was found that in calculations on certain systems where the TSD method is forced to delete a very large amount of information, the VLSD method is capable of achieving convergence in up to three times less iterations. Validation tests show that structural and electronic properties calculated with either method are accurate and in agreement with other electronic structure approaches.

Ruiz-Serrano, Álvaro; Skylaris, Chris-Kriton

2013-10-01

157

Advancing predictive models for particulate formation in turbulent flames via massively parallel direct numerical simulations.  

PubMed

Combustion of fossil fuels is likely to continue for the near future due to the growing trends in energy consumption worldwide. The increase in efficiency and the reduction of pollutant emissions from combustion devices are pivotal to achieving meaningful levels of carbon abatement as part of the ongoing climate change efforts. Computational fluid dynamics featuring adequate combustion models will play an increasingly important role in the design of more efficient and cleaner industrial burners, internal combustion engines, and combustors for stationary power generation and aircraft propulsion. Today, turbulent combustion modelling is hindered severely by the lack of data that are accurate and sufficiently complete to assess and remedy model deficiencies effectively. In particular, the formation of pollutants is a complex, nonlinear and multi-scale process characterized by the interaction of molecular and turbulent mixing with a multitude of chemical reactions with disparate time scales. The use of direct numerical simulation (DNS) featuring a state of the art description of the underlying chemistry and physical processes has contributed greatly to combustion model development in recent years. In this paper, the analysis of the intricate evolution of soot formation in turbulent flames demonstrates how DNS databases are used to illuminate relevant physico-chemical mechanisms and to identify modelling needs. PMID:25024412

Bisetti, Fabrizio; Attili, Antonio; Pitsch, Heinz

2014-08-13

158

Applying incremental best estimate directed search to optimize fuzzy logic controllers for a ball-and-beam system  

Microsoft Academic Search

Incremental best estimate directed search (IBEDS) is a computational controller optimization algorithm developed by the authors. It is a very fast and effective off-line controller parameter search method. Using the least mean square (LMS) learning algorithm with the training set, another controller with randomly initialized parameters is trained in an iterative procedure. In each iteration, the trained controller is evaluated

Feijun Song; Samuel M. Smith

2002-01-01

159

ArDM: a ton-scale LAr detector for direct Dark Matter searches  

NASA Astrophysics Data System (ADS)

The Argon Dark Matter (ArDM-1t) experiment is a ton-scale liquid argon (LAr) double-phase time projection chamber designed for direct Dark Matter searches. Such a device allows to explore the low energy frontier in LAr with a charge imaging detector. The ionization charge is extracted from the liquid into the gas phase and there amplified by the use of a Large Electron Multiplier in order to reduce the detection threshold. Direct detection of the ionization charge with fine spatial granularity, combined with a measurement of the amplitude and time evolution of the associated primary scintillation light, provide powerful tools for the identification of WIMP interactions against the background due to electrons, photons and possibly neutrons if scattering more than once. A one ton LAr detector is presently installed on surface at CERN to fully test all functionalities and it will be soon moved to an underground location. We will emphasize here the lessons learned from such a device for the design of a large LAr TPC for neutrino oscillation, proton decay and astrophysical neutrinos searches.

Marchionni, A.; Amsler, C.; Badertscher, A.; Boccone, V.; Bueno, A.; Carmona-Benitez, M. C.; Coleman, J.; Creus, W.; Curioni, A.; Daniel, M.; Dawe, E. J.; Degunda, U.; Gendotti, A.; Epprecht, L.; Horikawa, S.; Kaufmann, L.; Knecht, L.; Laffranchi, M.; Lazzaro, C.; Lightfoot, P. K.; Lussi, D.; Lozano, J.; Mavrokoridis, K.; Melgarejo, A.; Mijakowski, P.; Natterer, G.; Navas-Concha, S.; Otyugova, P.; de Prado, M.; Przewlocki, P.; Regenfus, C.; Resnati, F.; Robinson, M.; Rochet, J.; Romero, L.; Rondio, E.; Rubbia, A.; Scotto-Lavina, L.; Spooner, N. J. C.; Strauss, T.; Touramanis, C.; Ulbricht, J.; Viant, T.

2011-07-01

160

A Direct Dark Matter Search with the MAJORANA Low-Background Broad Energy Germanium Detector  

NASA Astrophysics Data System (ADS)

It is well established that a significant portion of our Universe is comprised of invisible, non-luminous matter, commonly referred to as dark matter. The detection and characterization of this missing matter is an active area of research in cosmology and particle astrophysics. A general class of candidates for non-baryonic particle dark matter is weakly interacting massive particles (WIMPs). WIMPs emerge naturally from supersymmetry with predicted masses between 1--1000 GeV. There are many current and near-future experiments that may shed light on the nature of dark matter by directly detecting WIMP-nucleus scattering events. The MAJORANA experiment will use p-type point contact (PPC) germanium detectors as both the source and detector to search for neutrinoless double-beta decay in 76Ge. These detectors have both exceptional energy resolution and low-energy thresholds. The low-energy performance of PPC detectors, due to their low-capacitance point-contact design, makes them suitable for direct dark matter searches. As a part of the research and development efforts for the MAJORANA experiment, a custom Canberra PPC detector has been deployed at the Kimballton Underground Research Facility in Ripplemead, Virginia. This detector has been used to perform a search for low-mass (< 10 GeV) WIMP induced nuclear recoils using a 221.49 live-day exposure. It was found that events originating near the surface of the detector plague the signal region, even after all cuts. For this reason, only an upper limit on WIMP induced nuclear recoils was placed. This limit is inconsistent with several recent claims to have observed light WIMP based dark matter.

Finnerty, Padraic Seamus

161

Plasmonic modulator utilizing three parallel metal-dielectric-metal waveguide directional coupler and elasto-optic effects  

NASA Astrophysics Data System (ADS)

We report, for the first time, on the design of a plasmonic modulator working on the principle of the elasto-optic effects in a directional coupling structure, utilizing three parallel metal-dielectric-metal waveguides. We propose to achieve the active switching of the power propagation using the elasto-optic effect and optimize the extinction ratio of the optical modulation. The device is characterized and numerically analyzed using the finite-element-method at the wavelengths of 1.55 ?m. For the modulator length of 2.33 ?m, the extinction ratio of the modulation is nearly 14 dB, and the calculated attenuation loss is 4.5 dB. The calculated driving voltage is 4.8 V for the given modulator. The effect of the applied voltage on the modulation is also analyzed.

Dwivedi, Ram Prakash; Lee, Hyun-Shik; Song, Jun-Hwa; An, Shinmo; Lee, El-Hang

2011-03-01

162

Parallel algorithm for solving Kepler's equation on Graphics Processing Units: Application to analysis of Doppler exoplanet searches  

Microsoft Academic Search

We present the results of a highly parallel Kepler equation solver using the Graphics Processing Unit (GPU) on a commercial nVidia GeForce 280GTX and the ``Compute Unified Device Architecture'' (CUDA) programming environment. We apply this to evaluate a goodness-of-fit statistic (e.g., chi) for Doppler observations of stars potentially harboring multiple planetary companions (assuming negligible planet planet interactions). Given the high-dimensionality

Eric B. Ford

2009-01-01

163

Parallel Recognition of Series-Parallel Graphs  

Microsoft Academic Search

Recently, He and Yesha gave an algorithm for recognizing directed series parallel graphs, in time O(log2n) with linearly many EREW processors. We give a new algorithm for this problem, based on a structural characterization of series parallel graphs in terms of their ear decompositions. Our algorithm can recognize undirected as well as directed series parallel graphs. It can be implemented

David Eppstein

1992-01-01

164

Direct searches for 3rd generation scalar leptoquarks at the Run II Tevatron  

NASA Astrophysics Data System (ADS)

This dissertation reports on a search for scalar Leptoquarks (LQ) decaying into third generation leptons and quarks. Based on extended gauge theories beyond the Standard Model, the Leptoquarks could be pair-produced in pp¯ collisions. A Leptoquark would decay into a lepton and a quark of the same generation. In our analysis we have assumed a third generation Leptoquark would decay to a tau-lepton and a b-quark with 100% branching ratio. We focus our analysis with tau decays to electrons and muons only. Three final states associating with such decays from the decays of the LQ LQ ? tau+tau- bb¯ process are used in our searches: e +e- E /T , mu+mu-bb¯ E /T , and emubb¯ E /T , where E /T represents the total transverse energy 'imbalance' in an event due to neutrinos decay from tau-leptons, and b denotes a b-quark jet. The direct experimental search has been performed using data collected by the CDF detector at the Tevatron Collider during 2002-2006. No experimental signals have been observed in CDF data with an integrated luminosity of 361 pb-1 of pp¯ collisions at a center-of-mass energy of 1.96 TeV. Using the next to leading order theoretical cross section calculations for scalar Leptoquark production in pp¯ collisions, we set new mass limits on third generation scalar Leptoquarks. We exclude the existence of third generation scalar Leptoquarks with masses below 115 GeV for leptonic tau decay channels.

Sun, Hao

165

Direct searches for dark matter: on the verge of something big  

NASA Astrophysics Data System (ADS)

After nearly two decades of work, direct searches for WIMP dark matter in our galaxy have started to probe the range of WIMP properties favored by supersymmetry. The next decade promises a large increase in the reach of experiments, with existing experiments, such as CDMS and EDLEWEISS, fielding larger arrays of detectors with lower backgrounds, and an exciting set of new technologies based on noble liquids and bubble chambers promising economical scale-up to very large mass detectors. Experiments currently under construction will deeply probe the parameter space of supersymmetric WIMP models, and will set the stage for very large-scale experiments to follow. I will survey these developments, highlighting physics issues driving several detection strategies, and the status, plans and reach of current and upcoming experiments.

Shutt, Tom

2006-04-01

166

Hybrid halftoning using direct multi-bit search (DMS) screen algorithm  

NASA Astrophysics Data System (ADS)

In this paper we propose a mathematical framework for multi-bit aperiodic clustered dot halftoning based on the Direct Multi-bit Search (DMS) algorithm. A pixel validation map is provided to the DMS algorithm to guide the formation of homogeneous clusters. The DMS algorithm operates without any user defined guidance, iteratively choosing the best drop absorptance level. An array of valid pixels is computed after each iteration that restricts the selection of pixels available to the DMS algorithm, improving the dot clustering. This process is repeated throughout the entire range of gray levels to create a visually pleasing multi-bit halftone screen. The resultant mask exhibits smoother appearance and improved detail rendering, compared to conventional clustered dot halftoning. Much of the improvements originate from the improved sampling of the aperiodic hybrid screen designs.

Chandu, Kartheek; Stanich, Mikel; Wu, Chai Wah; Trager, Barry

2014-01-01

167

Secondary scintillation yield from GEM and THGEM gaseous electron multipliers for direct dark matter search  

NASA Astrophysics Data System (ADS)

The search for alternatives to PMTs as photosensors in optical TPCs for rare event detection has significantly increased in the last few years. In particular, in view of the next generation large volume detectors, the use of photosensors with lower natural radioactivity, such as large area APDs or GM-APDs, with the additional possibility of sparse surface coverage, triggered the intense study of secondary scintillation production in micropattern electron multipliers, such as GEMs and THGEMs, as alternatives to the commonly used uniform electric field region between two parallel meshes. The much higher scintillation output obtained from the electron avalanches in such microstructures presents an advantage in those situations. The accurate knowledge of the amount of such scintillation is important for correct detector simulation and optimization. It will also serve as a benchmark for software tools developed and/or under development for the calculation of the amount of such scintillation.The secondary scintillation yield, or electroluminescence yield, in the electron avalanches of GEMs and THGEMs operating in gaseous xenon and argon has been determined for different gas pressures. At 1 bar, THGEMs deliver electroluminescence yields that are more than one order of magnitude higher when compared to those achieved in GEMs and two orders of magnitude when compared to those achieved in a uniform field gap. The THGEM electroluminescence yield presents a faster decrease with pressure when comparing to the GEM electroluminescence yield, reaching similar values to what is achieved in GEMs for xenon pressures of 2.5 bar, but still one order of magnitude higher than that produced in a uniform field gap. Another exception is the GEM operating in argon, which presents an electroluminescence yield similar to that produced in a uniform electric field gap, while the THGEM achieves yields that are more than one order of magnitude higher.

Monteiro, C. M. B.; Fernandes, L. M. P.; Veloso, J. F. C. A.; Oliveira, C. A. B.; dos Santos, J. M. F.

2012-07-01

168

MIG-15 and ERM-1 promote growth cone directional migration in parallel to UNC-116 and WVE-1  

PubMed Central

Neurons require precise targeting of their axons to form a connected network and a functional nervous system. Although many guidance receptors have been identified, much less is known about how these receptors signal to direct growth cone migration. We used Caenorhabditis elegans motoneurons to study growth cone directional migration in response to a repellent UNC-6 (netrin homolog) guidance cue. The evolutionarily conserved kinase MIG-15 [homolog of Nck-interacting kinase (NIK)] regulates motoneuron UNC-6-dependent repulsion through unknown mechanisms. Using genetics and live imaging techniques, we show that motoneuron commissural axon morphology defects in mig-15 mutants result from impaired growth cone motility and subsequent failure to migrate across longitudinal obstacles or retract extra processes. To identify new genes acting with mig-15, we screened for genetic enhancers of the mig-15 commissural phenotype and identified the ezrin/radixin/moesin ortholog ERM-1, the kinesin-1 motor UNC-116 and the actin regulator WVE-1 complex. Genetic analysis indicates that mig-15 and erm-1 act in the same genetic pathway to regulate growth cone migration and that this pathway functions in parallel to the UNC-116/WVE-1 pathway. Further, time-lapse imaging of growth cones in mutants suggests that UNC-116 might be required to stimulate protrusive activity at the leading edge, whereas MIG-15 and ERM-1 maintain low activity at the rear edge. Together, these results support a model in which the MIG-15 kinase and the UNC-116–WVE-1 complex act on opposite sides of the growth cone to promote robust directional migration.

Teuliere, Jerome; Gally, Christelle; Garriga, Gian; Labouesse, Michel; Georges-Labouesse, Elisabeth

2011-01-01

169

Stable computation of search directions for near-degenerate linear programming problems  

SciTech Connect

In this paper, we examine stability issues that arise when computing search directions ({delta}x, {delta}y, {delta} s) for a primal-dual path-following interior point method for linear programming. The dual step {delta}y can be obtained by solving a weighted least-squares problem for which the weight matrix becomes extremely il conditioned near the boundary of the feasible region. Hough and Vavisis proposed using a type of complete orthogonal decomposition (the COD algorithm) to solve such a problem and presented stability results. The work presented here addresses the stable computation of the primal step {delta}x and the change in the dual slacks {delta}s. These directions can be obtained in a straight-forward manner, but near-degeneracy in the linear programming instance introduces ill-conditioning which can cause numerical problems in this approach. Therefore, we propose a new method of computing {delta}x and {delta}s. More specifically, this paper describes and orthogonal projection algorithm that extends the COD method. Unlike other algorithms, this method is stable for interior point methods without assuming nondegeneracy in the linear programming instance. Thus, it is more general than other algorithms on near-degenerate problems.

Hough, P.D.

1997-03-01

170

Radiopurity of CaWO4 crystals for direct dark matter search with CRESST and EURECA  

NASA Astrophysics Data System (ADS)

The direct dark matter search experiment CRESST uses scintillating CaWO4 single crystals as targets for possible WIMP scatterings. An intrinsic radioactive contamination of the crystals as low as possible is crucial for the sensitivity of the detectors. In the past CaWO4 crystals operated in CRESST were produced by institutes in Russia and the Ukraine. Since 2011 CaWO4 crystals have also been grown at the crystal laboratory of the Technische Universität München (TUM) to better meet the requirements of CRESST and of the future tonne-scale multi-material experiment EURECA. The radiopurity of the raw materials and of first TUM-grown crystals was measured by ultra-low background ?-spectrometry. Two TUM-grown crystals were also operated as low-temperature detectors at a test setup in the Gran Sasso underground laboratory. These measurements were used to determine the crystals' intrinsic ?-activities which were compared to those of crystals produced at other institutes. The total ?-activities of TUM-grown crystals as low as 1.23±0.06 mBq/kg were found to be significantly smaller than the activities of crystals grown at other institutes typically ranging between ~ 15 mBq/kg and ~ 35 mBq/kg.

Münster, A.; Sivers, M. v.; Angloher, G.; Bento, A.; Bucci, C.; Canonica, L.; Erb, A.; Feilitzsch, F. v.; Gorla, P.; Gütlein, A.; Hauff, D.; Jochum, J.; Kraus, H.; Lanfranchi, J.-C.; Laubenstein, M.; Loebell, J.; Ortigoza, Y.; Petricca, F.; Potzel, W.; Pröbst, F.; Puimedon, J.; Reindl, F.; Roth, S.; Rottler, K.; Sailer, C.; Schäffner, K.; Schieck, J.; Scholl, S.; Schönert, S.; Seidel, W.; Stodolsky, L.; Strandhagen, C.; Strauss, R.; Tanzke, A.; Uffinger, M.; Ulrich, A.; Usherov, I.; Wawoczny, S.; Willers, M.; Wüstrich, M.; Zöller, A.

2014-05-01

171

A Bayesian view of the current status of dark matter direct searches  

NASA Astrophysics Data System (ADS)

Bayesian statistical methods offer a simple and consistent framework for incorporating uncertainties into a multi-parameter inference problem. In this work we apply these methods to a selection of current direct dark matter searches. We consider the simplest scenario of spin-independent elastic WIMP scattering, and infer the WIMP mass and cross-section from the experimental data with the essential systematic uncertainties folded into the analysis. We find that when uncertainties in the scintillation efficiency of XENON100 have been accounted for, the resulting exclusion limit is not sufficiently constraining to rule out the CoGeNT preferred parameter region, contrary to previous claims. In the same vein, we also investigate the impact of astrophysical uncertainties on the preferred WIMP parameters. We find that within the class of smooth and isotropic WIMP velocity distributions, it is difficult to reconcile the DAMA and the CoGeNT preferred regions by tweaking the astrophysics parameters alone. If we demand compatibility between these experiments, then the inference process naturally concludes that a high value for the sodium quenching factor for DAMA is preferred.

Arina, Chiara; Hamann, Jan; Wong, Yvonne Y. Y.

2011-09-01

172

The Influence of Career Indecision on the Strong Interest Inventory and the Self-Directed Search: A Pilot Study.  

ERIC Educational Resources Information Center

A pilot study was conducted with 48 adults to determine if career indecision/dissatisfaction as indicated by flat Strong Interest Inventory (SII) (L. Harmon, J. Hansen, F. Borgen, and A. Hammer, 1994) profiles corresponded with flat profiles on the Self-Directed Search (SDS) and to determine if indecision affected scores on SII Personal Style…

Rowell, R. Kevin

173

The ArDM project: a Direct Detection Experiment, based on Liquid Argon, for the Search of Dark Matter  

Microsoft Academic Search

ArDM aims at developing and operating large liquefied noble gas detectors to search for direct evidence of Weakly Interacting Massive Particles (WIMP) as Dark Matter in the universe. An approximately 1-ton liquid argon prototype is designed and assembled at the time being, in order to assess the validity of the design. Our setup addresses the possibility to independently detect ionization

Lilian Kaufmann; André Rubbia

2007-01-01

174

Status Report of Ardm Project:. a New Direct Detection Experiment, Based on Liquid Argon, for the Search of Dark Matter  

Microsoft Academic Search

The goal of the ArDM project is to develop and operate a detector to search for direct evidence of Weakly Interacting Massive Particle (WIMP) as Dark Matter in the Universe. The experimental approach aims at detecting recoils of Argon nuclei induced by the collisions of WIMPs. Our immediate plan is to fully design and build a 1 ton prototype. This

M. Messina; A. Rubbia

2006-01-01

175

Comparing the Chinese Career Key and the Self-Directed Search with High School Girls in Hong Kong  

ERIC Educational Resources Information Center

A career interest inventory, the Chinese Career Key (CCK) adapted from the Career Key based on Holland's theory of vocational choice, was studied. The purpose of the study was to further examine the psychometric qualities and user satisfaction of the CCK by comparing it to the Self-Directed Search. Students at a girls' public high school (N = 130)…

Ting, Siu-Man Raymond

2007-01-01

176

A Comparison Study of the Paper-and-Pencil, Personal Computer, and Internet Versions of Holland's Self-Directed Search  

ERIC Educational Resources Information Center

The authors examined the extent to which the Realistic, Investigative, Artistic, Social, Enterprising, and Conventional scales and 3-point codes of the Self-Directed Search may be considered statistically and practically equivalent across 3 different modes of administration: paper-and-pencil, personal computer, and Internet. Student preferences…

Lumsden, Jill A.; Sampson, James P., Jr.; Reardon, Robert C.; Lenz, Janet G.; Peterson, Gary W.

2004-01-01

177

Using the Self-Directed Search in Research: Selecting a Representative Pool of Items to Measure Vocational Interests  

ERIC Educational Resources Information Center

Using Item Response Theory (IRT) and Confirmatory Factor Analysis (CFA), the goal of this study was to select a reduced pool of items from the French Canadian version of the Self-Directed Search--Activities Section (Holland, Fritzsche, & Powell, 1994). Two studies were conducted. Results of Study 1, involving 727 French Canadian students, showed…

Poitras, Sarah-Caroline; Guay, Frederic; Ratelle, Catherine F.

2012-01-01

178

A Java-based simulation manager for optimization and response surface methodology in multiple-response parallel simulation  

Microsoft Academic Search

This paper describes a Java-based system for allocating simulation trials to a set of P parallel processors for carrying out a simulation study involving direct-search optimization or response surface methodology. Unlike distributed simulation, where a simulation model is decomposed and its parts run in a parallel environment, the parallel replications approach allows a simulation model to run to completion with

William E. Biles; Jack P. C. Kleijnen

1999-01-01

179

Reliability analysis of a direct parallel connected n+1 redundant power system based on highly reliable DC\\/DC modules  

Microsoft Academic Search

An n+1 redundant system using modular hybrid DC\\/DC converters connected in parallel where the normally associated isolation diodes are omitted is described. Reliability and efficiency analysis of the systems was performed, based on a comparison between the system described and a system based on a conventional (uninterruptible power system) UPS with added redundant functions. It is concluded that the proposed

L. Thorsell; P. Lindman

1988-01-01

180

Experimental discovery of sRNAs in Vibrio cholerae by direct cloning, 5S\\/tRNA depletion and parallel sequencing  

Microsoft Academic Search

Direct cloning and parallel sequencing, an extremely powerful method for microRNA (miRNA) discovery, has not yet been applied to bacterial tran- scriptomes. Here we present sRNA-Seq, an unbi- ased method that allows for interrogation of the entire small, non-coding RNA (sRNA) repertoire in any prokaryotic or eukaryotic organism. This method includes a novel treatment that depletes total RNA fractions of

Jane M. Liu; Jonathan Livny; Michael S. Lawrence; Marc D. Kimball; Matthew K. Waldor; Andrew Camilli

2009-01-01

181

Application of a directed search to global steering of single gimballed CMGs  

NASA Astrophysics Data System (ADS)

A guided depth-first search that manages null motion about torque-producing trajectories calculated with a singularity-robust (SR) inverse is proposed as a practical feedforward steering law that can globally avoid (or minimize the impact of) singular states in minimally-redundant single gimballed CMG systems. Cost and heuristic functions are defined to guide the search procedure in improving CMG trajectories. On-orbit implementation of the steering law is proposed as an extension to momentum management algorithms. A set of simulation examples is presented, illustrating the search performance for a 4-CMG pyramid-mounted array. Sensitivities of feedforward gimbal trajectories are examined in the presence of unmodeled disturbances, and techniques are proposed for avoiding excessive divergence.

Paradiso, Joseph A.

182

A comparison of evolution strategies with other direct search methods in the presence of noise  

Microsoft Academic Search

Evolution strategies are general, nature-inspired heuristics for search and optimization. Due to their use of populations of candidate solutions and their advanced adaptation schemes, there is a common belief that evolution strategies are especially useful for optimization in the presence of noise. Empirical evidence as well as a number of theoretical findings with respect to the performance of evolution strategies

Dirk V. Arnold; Hans-Georg Beyer

2003-01-01

183

Target resolution in visual search involves the direct suppression of distractors: evidence from electrophysiology.  

PubMed

Attentional selection requires both the enhancement of target stimuli and the suppression of distractors. Target enhancement and distractor suppression have been associated with separable components of the lateralized event-related potential: the target negativity and distractor positivity (Pd). We examined the distractor suppression mechanisms indexed by the Pd. The Pd may reflect mechanisms that guide attention away from distractors during search or mechanisms involved in the subsequent resolution of target features. To determine which of these alternatives was more likely, we had participants view search arrays that contained only a target, only a distractor, or both. The Pd elicited by distractors was substantially larger when the display also contained a target, consistent with the idea that this component reflects a mechanism of distractor suppression activated during the resolution and disambiguation of target features. PMID:22176697

Hilimire, Matthew R; Hickey, Clayton; Corballis, Paul M

2012-04-01

184

Adaptive direction search algorithms based on motion correlation for block motion estimation  

Microsoft Academic Search

The new video coding standard, H.264\\/AVC, has achieved significant compression gain by utilizing several advanced techniques. Block-Matching Motion Estimation is one of the most important elements to reduce the motion residual. However, it results in heavy computational burden and limits the application for real-time video service. In this paper, a fast motion estimation algorithm called Simulated Annealing Adaptive Search (SAAS)

Zhiru Shi; W. A. C. Fernando; A. Kondoz

2011-01-01

185

Direct search for charged higgs bosons in decays of top quarks.  

PubMed

We present a search for charged Higgs bosons in decays of pair-produced top quarks in pp collisions at sqrt[s] = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider. With no evidence for signal, we exclude most regions of the ( M(H+/-),tan(beta)) parameter space where the decay t--> H(+)b has a branching fraction >0.36 and B(H+/--->tau(nu)(tau)) is large. PMID:11955191

Abazov, V M; Abbott, B; Abdesselam, A; Abolins, M; Abramov, V; Acharya, B S; Adams, D L; Adams, M; Ahmed, S N; Alexeev, G D; Alves, G A; Amos, N; Anderson, E W; Baarmand, M M; Babintsev, V V; Babukhadia, L; Bacon, T C; Baden, A; Baldin, B; Balm, P W; Banerjee, S; Barberis, E; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Bean, A; Begel, M; Belyaev, A; Beri, S B; Bernardi, G; Bertram, I; Besson, A; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Bhattacharjee, M; Blazey, G; Blessing, S; Boehnlein, A; Bojko, N I; Borcherding, F; Bos, K; Brandt, A; Breedon, R; Briskin, G; Brock, R; Brooijmans, G; Bross, A; Buchholz, D; Buehler, M; Buescher, V; Burtovoi, V S; Butler, J M; Canelli, F; Carvalho, W; Casey, D; Casilum, Z; Castilla-Valdez, H; Chakraborty, D; Chan, K M; Chekulaev, S V; Cho, D K; Choi, S; Chopra, S; Christenson, J H; Chung, M; Claes, D; Clark, A R; Cochran, J; Coney, L; Connolly, B; Cooper, W E; Coppage, D; Cummings, M A C; Cutts, D; Davis, G A; Davis, K; De, K; de Jong, S J; Del Signore, K; Demarteau, M; Demina, R; Demine, P; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Di Loreto, G; Doulas, S; Draper, P; Ducros, Y; Dudko, L V; Duensing, S; Duflot, L; Dugad, S R; Dyshkant, A; Edmunds, D; Ellison, J; Elvira, V D; Engelmann, R; Eno, S; Eppley, G; Ermolov, P; Eroshin, O V; Estrada, J; Evans, H; Evdokimov, V N; Fahland, T; Feher, S; Fein, D; Ferbel, T; Filthaut, F; Fisk, H E; Fisyak, Y; Flattum, E; Fleuret, F; Fortner, M; Frame, K C; Fuess, S; Gallas, E; Galyaev, A N; Gao, M; Gavrilov, V; Genik, R J; Genser, K; Gerber, C E; Gershtein, Y; Gilmartin, R; Ginther, G; Gómez, B; Gómez, G; Goncharov, P I; González Solís, J L; Gordon, H; Goss, L T; Gounder, K; Goussiou, A; Graf, N; Graham, G; Grannis, P D; Green, J A; Greenlee, H; Grinstein, S; Groer, L; Grünendahl, S; Gupta, A; Gurzhiev, S N; Gutierrez, G; Gutierrez, P; Hadley, N J; Haggerty, H; Hagopian, S; Hagopian, V; Hall, R E; Hanlet, P; Hansen, S; Hauptman, J M; Hays, C; Hebert, C; Hedin, D; Heinson, A P; Heintz, U; Heuring, T; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Huang, Y; Illingworth, R; Ito, A S; Jaffré, M; Jain, S; Jesik, R; Johns, K; Johnson, M; Jonckheere, A; Jones, M; Jöstlein, H; Juste, A; Kahn, S; Kajfasz, E; Kalinin, A M; Karmanov, D; Karmgard, D; Kehoe, R; Kharchilava, A; Kim, S K; Klima, B; Knuteson, B; Ko, W; Kohli, J M; Kostritskiy, A V; Kotcher, J; Kotwal, A V; Kozelov, A V; Kozlovsky, E A; Krane, J; Krishnaswamy, M R; Krivkova, P; Krzywdzinski, S; Kubantsev, M; Kuleshov, S; Kulik, Y; Kunori, S; Kupco, A; Kuznetsov, V E; Landsberg, G; Leflat, A; Leggett, C; Lehner, F; Li, J; Li, Q Z; Lima, J G R; Lincoln, D; Linn, S L; Linnemann, J; Lipton, R; Lucotte, A; Lueking, L; Lundstedt, C; Luo, C; Maciel, A K A; Madaras, R J; Malyshev, V L; Manankov, V; Mao, H S; Marshall, T; Martin, M I; Martin, R D; Mauritz, K M; May, B; Mayorov, A A; McCarthy, R; McDonald, J; McMahon, T; Melanson, H L; Merkin, M; Merritt, K W; Miao, C; Miettinen, H; Mihalcea, D; Mishra, C S; Mokhov, N; Mondal, N K; Montgomery, H E; Moore, R W; Mostafa, M; da Motta, H; Nagy, E; Nang, F; Narain, M; Narasimham, V S; Neal, H A; Negret, J P; Negroni, S; Nunnemann, T; O'Neil, D; Oguri, V; Olivier, B; Oshima, N; Padley, P; Pan, L J; Papageorgiou, K; Para, A; Parashar, N; Partridge, R; Parua, N; Paterno, M; Patwa, A; Pawlik, B; Perkins, J; Peters, M; Peters, O; Pétroff, P; Piegaia, R; Piekarz, H; Pope, B G; Popkov, E; Prosper, H B; Protopopescu, S; Qian, J; Raja, R; Rajagopalan, S; Ramberg, E; Rapidis, P A; Reay, N W; Reucroft, S; Rha, J; Ridel, M; Rijssenbeek, M; Rockwell, T; Roco, M; Rubinov, P; Ruchti, R; Rutherfoord, J; Sabirov, B M; Santoro, A; Sawyer, L; Schamberger, R D; Schellman, H; Schwartzman, A; Sen, N; Shabalina, E; Shivpuri, R K; Shpakov, D; Shupe, M; Sidwell, R A; Simak, V; Singh, H; Singh, J B; Sirotenko, V; Slattery, P; Smith, E; Smith, R P; Snihur, R; Snow, G R; Snow, J; Snyder, S; Solomon, J; Sorín, V; Sosebee, M; Sotnikova, N; Soustruznik, K; Souza, M; Stanton, N R; Steinbrück, G; Stephens, R W; Stichelbaut, F; Stoker, D; Stolin, V; Stoyanova, D A; Strauss, M; Strovink, M; Stutte, L; Sznajder, A; Taylor, W; Tentindo-Repond, S; Tripathi, S M; Trippe, T G; Turcot, A S; Tuts, P M; van Gemmeren, P; Vaniev, V; Van Kooten, R; Varelas, N; Vertogradov, L S; Volkov, A A; Vorobiev, A P; Wahl, H D; Wang, H; Wang, Z-M; Warchol, J; Watts, G; Wayne, M; Weerts, H; White, A; White, J T; Whiteson, D; Wightman, J A; Wijngaarden, D A; Willis, S; Wimpenny, S J; Womersley, J; Wood, D R; Yamada, R; Yamin, P; Yasuda, T; Yatsunenko, Y A; Yip, K; Youssef, S; Yu, J; Yu, Z; Zanabria, M; Zheng, H; Zhou, Z; Zielinski, M; Zieminska, D; Zieminski, A; Zutshi, V; Zverev, E G; Zylberstejn, A

2002-04-15

186

Direct Search for Charged Higgs Bosons in Decays of Top Quarks  

NASA Astrophysics Data System (ADS)

We present a search for charged Higgs bosons in decays of pair-produced top quarks in ppbar collisions at (s) = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider. With no evidence for signal, we exclude most regions of the ( MH+/-,tan?) parameter space where the decay t--> H+b has a branching fraction >0.36 and B(H+/--->???) is large.

Abazov, V. M.; Abbott, B.; Abdesselam, A.; Abolins, M.; Abramov, V.; Acharya, B. S.; Adams, D. L.; Adams, M.; Ahmed, S. N.; Alexeev, G. D.; Alves, G. A.; Amos, N.; Anderson, E. W.; Baarmand, M. M.; Babintsev, V. V.; Babukhadia, L.; Bacon, T. C.; Baden, A.; Baldin, B.; Balm, P. W.; Banerjee, S.; Barberis, E.; Baringer, P.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bauer, D.; Bean, A.; Begel, M.; Belyaev, A.; Beri, S. B.; Bernardi, G.; Bertram, I.; Besson, A.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Bhattacharjee, M.; Blazey, G.; Blessing, S.; Boehnlein, A.; Bojko, N. I.; Borcherding, F.; Bos, K.; Brandt, A.; Breedon, R.; Briskin, G.; Brock, R.; Brooijmans, G.; Bross, A.; Buchholz, D.; Buehler, M.; Buescher, V.; Burtovoi, V. S.; Butler, J. M.; Canelli, F.; Carvalho, W.; Casey, D.; Casilum, Z.; Castilla-Valdez, H.; Chakraborty, D.; Chan, K. M.; Chekulaev, S. V.; Cho, D. K.; Choi, S.; Chopra, S.; Christenson, J. H.; Chung, M.; Claes, D.; Clark, A. R.; Cochran, J.; Coney, L.; Connolly, B.; Cooper, W. E.; Coppage, D.; Cummings, M. A.; Cutts, D.; Davis, G. A.; Davis, K.; de, K.; de Jong, S. J.; del Signore, K.; Demarteau, M.; Demina, R.; Demine, P.; Denisov, D.; Denisov, S. P.; Desai, S.; Diehl, H. T.; Diesburg, M.; di Loreto, G.; Doulas, S.; Draper, P.; Ducros, Y.; Dudko, L. V.; Duensing, S.; Duflot, L.; Dugad, S. R.; Dyshkant, A.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Engelmann, R.; Eno, S.; Eppley, G.; Ermolov, P.; Eroshin, O. V.; Estrada, J.; Evans, H.; Evdokimov, V. N.; Fahland, T.; Feher, S.; Fein, D.; Ferbel, T.; Filthaut, F.; Fisk, H. E.; Fisyak, Y.; Flattum, E.; Fleuret, F.; Fortner, M.; Frame, K. C.; Fuess, S.; Gallas, E.; Galyaev, A. N.; Gao, M.; Gavrilov, V.; Genik, R. J.; Genser, K.; Gerber, C. E.; Gershtein, Y.; Gilmartin, R.; Ginther, G.; Gómez, B.; Gómez, G.; Goncharov, P. I.; González Solís, J. L.; Gordon, H.; Goss, L. T.; Gounder, K.; Goussiou, A.; Graf, N.; Graham, G.; Grannis, P. D.; Green, J. A.; Greenlee, H.; Grinstein, S.; Groer, L.; Grünendahl, S.; Gupta, A.; Gurzhiev, S. N.; Gutierrez, G.; Gutierrez, P.; Hadley, N. J.; Haggerty, H.; Hagopian, S.; Hagopian, V.; Hall, R. E.; Hanlet, P.; Hansen, S.; Hauptman, J. M.; Hays, C.; Hebert, C.; Hedin, D.; Heinson, A. P.; Heintz, U.; Heuring, T.; Hildreth, M. D.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Huang, Y.; Illingworth, R.; Ito, A. S.; Jaffré, M.; Jain, S.; Jesik, R.; Johns, K.; Johnson, M.; Jonckheere, A.; Jones, M.; Jöstlein, H.; Juste, A.; Kahn, S.; Kajfasz, E.; Kalinin, A. M.; Karmanov, D.; Karmgard, D.; Kehoe, R.; Kharchilava, A.; Kim, S. K.; Klima, B.; Knuteson, B.; Ko, W.; Kohli, J. M.; Kostritskiy, A. V.; Kotcher, J.; Kotwal, A. V.; Kozelov, A. V.; Kozlovsky, E. A.; Krane, J.; Krishnaswamy, M. R.; Krivkova, P.; Krzywdzinski, S.; Kubantsev, M.; Kuleshov, S.; Kulik, Y.; Kunori, S.; Kupco, A.; Kuznetsov, V. E.; Landsberg, G.; Leflat, A.; Leggett, C.; Lehner, F.; Li, J.; Li, Q. Z.; Lima, J. G.; Lincoln, D.; Linn, S. L.; Linnemann, J.; Lipton, R.; Lucotte, A.; Lueking, L.; Lundstedt, C.; Luo, C.; Maciel, A. K.; Madaras, R. J.; Malyshev, V. L.; Manankov, V.; Mao, H. S.; Marshall, T.; Martin, M. I.; Martin, R. D.; Mauritz, K. M.; May, B.; Mayorov, A. A.; McCarthy, R.; McDonald, J.; McMahon, T.; Melanson, H. L.; Merkin, M.; Merritt, K. W.; Miao, C.; Miettinen, H.; Mihalcea, D.; Mishra, C. S.; Mokhov, N.; Mondal, N. K.; Montgomery, H. E.; Moore, R. W.; Mostafa, M.; da Motta, H.; Nagy, E.; Nang, F.; Narain, M.; Narasimham, V. S.; Neal, H. A.; Negret, J. P.; Negroni, S.; Nunnemann, T.; O'Neil, D.; Oguri, V.; Olivier, B.; Oshima, N.; Padley, P.; Pan, L. J.; Papageorgiou, K.; Para, A.; Parashar, N.; Partridge, R.; Parua, N.; Paterno, M.; Patwa, A.; Pawlik, B.; Perkins, J.; Peters, M.; Peters, O.; Pétroff, P.; Piegaia, R.; Piekarz, H.; Pope, B. G.; Popkov, E.; Prosper, H. B.; Protopopescu, S.; Qian, J.; Raja, R.; Rajagopalan, S.; Ramberg, E.; Rapidis, P. A.; Reay, N. W.; Reucroft, S.; Rha, J.; Ridel, M.; Rijssenbeek, M.; Rockwell, T.; Roco, M.; Rubinov, P.; Ruchti, R.; Rutherfoord, J.; Sabirov, B. M.; Santoro, A.; Sawyer, L.; Schamberger, R. D.; Schellman, H.; Schwartzman, A.; Sen, N.; Shabalina, E.; Shivpuri, R. K.; Shpakov, D.; Shupe, M.; Sidwell, R. A.; Simak, V.; Singh, H.; Singh, J. B.; Sirotenko, V.; Slattery, P.; Smith, E.; Smith, R. P.; Snihur, R.; Snow, G. R.; Snow, J.; Snyder, S.; Solomon, J.; Sorín, V.; Sosebee, M.; Sotnikova, N.; Soustruznik, K.; Souza, M.; Stanton, N. R.; Steinbrück, G.; Stephens, R. W.; Stichelbaut, F.; Stoker, D.; Stolin, V.; Stoyanova, D. A.; Strauss, M.; Strovink, M.; Stutte, L.; Sznajder, A.; Taylor, W.; Tentindo-Repond, S.; Tripathi, S. M.; Trippe, T. G.; Turcot, A. S.; Tuts, P. M.; van Gemmeren, P.; Vaniev, V.; van Kooten, R.; Varelas, N.; Vertogradov, L. S.; Volkov, A. A.

2002-04-01

187

Spin-Seebeck effect on the surface of a topological insulator due to nonequilibrium spin-polarization parallel to the direction of thermally driven electronic transport  

NASA Astrophysics Data System (ADS)

We study the transverse spin-Seebeck effect (SSE) on the surface of a three-dimensional topological insulator (TI) thin film, such as Bi2Se3, which is sandwiched between two normal metal leads. The temperature bias ?T applied between the leads generates surface charge current which becomes spin polarized due to strong spin-orbit coupling on the TI surface, with polarization vector acquiring a component Px?60% parallel to the direction of transport. When the third nonmagnetic voltage probe is attached to the portion of the TI surface across its width Ly, pure spin current will be injected into the probe where the inverse spin Hall effect (ISHE) converts it into a voltage signal |VISHE|max/?T ?2.5?V/K (assuming the SH angle of the Pt voltage probe and Ly=1 mm). The existence of predicted nonequilibrium spin polarization parallel to the direction of electronic transport and the corresponding electron-driven SSE crucially relies on orienting quintuple layers (QLs) of Bi2Se3 orthogonal to the TI surface and tilted by 45? with respect to the direction of transport. Our analysis is based on the Landauer-Büttiker-type formula for spin currents in the leads of a multiterminal quantum-coherent junction, which is constructed by using nonequilibrium Green function formalism within which we show how to take into account arbitrary orientation of QLs via the self-energy describing coupling between semi-infinite normal metal leads and the TI sample.

Chang, Po-Hao; Mahfouzi, Farzad; Nagaosa, Naoto; Nikoli?, Branislav K.

2014-05-01

188

How choosy should I be? The relative searching time predicts evolution of choosiness under direct sexual selection  

PubMed Central

Most theoretical research in sexual selection has focused on indirect selection. However, empirical studies have not strongly supported indirect selection. A well-established finding is that direct benefits and costs exert a strong influence on the evolution of mate choice. We present an analytical model in which unilateral mate choice evolves solely by direct sexual selection on choosiness. We show this is sufficient to generate the evolution of all possible levels of choosiness, because of the fundamental trade-off between mating rate and mating benefits. We further identify the relative searching time (RST, i.e. the proportion of lifetime devoted to searching for mates) as a predictor of the effect of any variable affecting the mating rate on the evolution of choosiness. We show that the RST: (i) allows one to make predictions about the evolution of choosiness across a wide variety of mating systems; (ii) encompasses all alternative variables proposed thus far to explain the evolution of choosiness by direct sexual selection; and (iii) can be empirically used to infer qualitative differences in choosiness.

Etienne, Loic; Rousset, Francois; Godelle, Bernard; Courtiol, Alexandre

2014-01-01

189

The ArDM project: a Direct Detection Experiment, based on Liquid Argon, for the Search of Dark Matter  

NASA Astrophysics Data System (ADS)

ArDM aims at developing and operating large liquefied noble gas detectors to search for direct evidence of Weakly Interacting Massive Particles (WIMP) as Dark Matter in the universe. An approximately 1-ton liquid argon prototype is designed and assembled at the time being, in order to assess the validity of the design. Our setup addresses the possibility to independently detect ionization and scintillation signals, in order to being able to efficiently detect WIMPs and discriminate their signals from various background signals. This goal and the conceptual design of the detector are described.

Kaufmann, Lilian; Rubbia, André

2007-11-01

190

Status Report of Ardm Project:. a New Direct Detection Experiment, Based on Liquid Argon, for the Search of Dark Matter  

NASA Astrophysics Data System (ADS)

The goal of the ArDM project is to develop and operate a detector to search for direct evidence of Weakly Interacting Massive Particle (WIMP) as Dark Matter in the Universe. The experimental approach aims at detecting recoils of Argon nuclei induced by the collisions of WIMPs. Our immediate plan is to fully design and build a 1 ton prototype. This will involve a HV system, charge amplification + readout and light readout, as described in this paper. Our first milestone is a proof of principle on gamma-rays and beta electron vs nuclear recoils discrimination.

Messina, M.; Rubbia, A.

2006-04-01

191

Parallel algorithm development  

SciTech Connect

Rapid changes in parallel computing technology are causing significant changes in the strategies being used for parallel algorithm development. One approach is simply to write computer code in a standard language like FORTRAN 77 or with the expectation that the compiler will produce executable code that will run in parallel. The alternatives are: (1) to build explicit message passing directly into the source code; or (2) to write source code without explicit reference to message passing or parallelism, but use a general communications library to provide efficient parallel execution. Application of these strategies is illustrated with examples of codes currently under development.

Adams, T.F.

1996-06-01

192

Searching for Pollution HavensThe Impact of Environmental Regulations on Foreign Direct Investment  

Microsoft Academic Search

This study takes a fresh look at the regulatory determinants of foreign direct investment (FDI) by asking whether the stringency and sustainability of environmental regulations affect FDI flows across 25 Western and Eastern European countries. Unlike the earlier literature, which considered only host country characteristics, this article focuses on the difference in the regulatory environments in home and host economies.

Mariana Spatareanu

2007-01-01

193

Algorithm for the normal direction error analysis of surface mesh grids for searching measuring points  

Microsoft Academic Search

The objective of this paper is to explore how to determine the number of recommended measuring points and their measuring positions in the surface measurement of coordinate measuring machines. This paper starts from the design blueprint of a surface. The mesh grids data on the surface are obtained to conduct Coons bicubic surface patch. The normal direction error between this

Zone-ching Lin; Q. Y. Liu

2000-01-01

194

Progression from South-Directed to Orogen-Parallel Mid-Crustal Flow on the Southern Margin of the Tibetan Plateau, Ama Drime Massif, Tibet  

NASA Astrophysics Data System (ADS)

In the South Tibetan Himalaya, two major detachment systems are exposed in the Ama Drime and Mount Everest Massifs. These structures represent a fundamental shift in the dynamics of the Himalayan orogen, recording a progression from south-directed to orogen-parallel mid-crustal flow and exhumation. The South Tibetan detachment system (STDS) accommodated exhumation of the Greater Himalayan series (GHS) until the Middle Miocene. A relatively narrow mylonite zone that progressed into a brittle detachment accommodated exhumation of the GHS. Northward, in the down-dip direction (Dzakaa Chu and Doya La), a 1-km-wide distributed zone of deformation that lacks a foliation-parallel brittle detachment characterizes the STDS. Leucogranites in the footwall of the STDS range between 17-18 Ma. Previously published 40Ar/39Ar ages suggest that movement on the STDS ended by ~ 16 Ma in Rongbuk Valley and ~ 13 Ma near Dinggye. This once continuous section of the STDS is displaced by the trans- Himalayan Ama Drime Massif and Xainza-Dinggye graben. Two oppositely dipping normal faults and shear zones that bound the Ama Drime Massif record orogen-parallel extension. During exhumation, deformation was partitioned into relatively narrow (100-300-m-thick) mylonite zones that progressed into brittle faults/detachments, which offset Quaternary deposits. U(-Th-)Pb geochronology of mafic lenses suggests that the core of the ADM reached granulite facies at ~ 15 Ma. Leucogranites in the footwall of the detachment faults range between 12-11 Ma: significantly younger than those related to movement on the STDS. Previously published 40Ar/39Ar ages from the eastern limb of the Ama Drime Massif suggest that exhumation progressed into the footwall of the Nyüonno detachment between ~ 13-10 Ma. (U-Th)/He apatite ages record a minimum exhumation rate of ~ 1mm/yr between 1.5-3.0 Ma that was enhanced by focused denudation in the trans-Himalayan Arun River gorge. Together these bracket the timing (~ 12 Ma) of a transition from south-directed to orogen-parallel mid-crustal flow and associated graben formation and exhumation along the southern margin of the Tibetan Plateau.

Jessup, M. J.; Cottle, J. M.; Newell, D. L.; Berger, A. L.; Spotila, J. A.

2008-12-01

195

Experimental discovery of sRNAs in Vibrio cholerae by direct cloning, 5S/tRNA depletion and parallel sequencing.  

PubMed

Direct cloning and parallel sequencing, an extremely powerful method for microRNA (miRNA) discovery, has not yet been applied to bacterial transcriptomes. Here we present sRNA-Seq, an unbiased method that allows for interrogation of the entire small, non-coding RNA (sRNA) repertoire in any prokaryotic or eukaryotic organism. This method includes a novel treatment that depletes total RNA fractions of highly abundant tRNAs and small subunit rRNA, thereby enriching the starting pool for sRNA transcripts with novel functionality. As a proof-of-principle, we applied sRNA-Seq to the human pathogen Vibrio cholerae. Our results provide information, at unprecedented depth, on the complexity of the sRNA component of a bacterial transcriptome. From 407 039 sequence reads, all 20 known V. cholerae sRNAs, 500 new, putative intergenic sRNAs and 127 putative antisense sRNAs were identified in a limited number of growth conditions examined. In addition, characterization of a subset of the newly identified transcripts led to the identification of a novel sRNA regulator of carbon metabolism. Collectively, these results strongly suggest that the number of sRNAs in bacteria has been greatly underestimated and that future efforts to analyze bacterial transcriptomes will benefit from direct cloning and parallel sequencing experiments aided by 5S/tRNA depletion. PMID:19223322

Liu, Jane M; Livny, Jonathan; Lawrence, Michael S; Kimball, Marc D; Waldor, Matthew K; Camilli, Andrew

2009-04-01

196

Integrating Direct CP Search and CP-based Column Generation for the Airline Crew Assignment Problem  

Microsoft Academic Search

. We introduce a hybrid approach integrating CP-based ColumnGeneration and pure CP methods. It is being applied to the largescale optimization problem of Airline Crew Assignment. The combinationof methods from CP and OR results in an algorithm that overcomesthe inherent weaknesses of each approach. First numerical results showthe superiority of the hybrid algorithm in comparison to direct CP andCP-based Column

Meinolf Sellmann; Kyriakos Zervoudakis; Panagiotis Stamatopoulos; Torsten Fahle

2000-01-01

197

Performance Prediction of Large Parallel Applications using Parallel Simulations  

Microsoft Academic Search

Accurate simulation of large parallel applications can be facilitated with the use of direct execution and parallel discrete event simulation. This paper describes the use of COMPASS, a direct execution-driven, parallel simulator for performance prediction of programs that include both communication and I\\/O intensive applications. The simulator has been used to predict the performance of such applications on both distributed

Rajive Bagrodia; Ewa Deeljman; Steven Docy; Thomas Phan

1999-01-01

198

Self-Tuning Parallelism  

Microsoft Academic Search

Assigning additional processors to a parallel application may slow it down or lead to poor computer utilization. This paper\\u000a demonstrates that it is possible for an application to automatically choose its own, optimal degree of parallelism. The technique\\u000a is based on a simple binary search procedure for finding the optimal number of processors, subject to one of the following\\u000a criteria:

Otilia Werner-kytölä; Walter F. Tichy

2000-01-01

199

Direct search for a ferromagnetic phase in a heavily overdoped nonsuperconducting copper oxide  

PubMed Central

The doping of charge carriers into the CuO2 planes of copper oxide Mott insulators causes a gradual destruction of antiferromagnetism and the emergence of high-temperature superconductivity. Optimal superconductivity is achieved at a doping concentration p beyond which further increases in doping cause a weakening and eventual disappearance of superconductivity. A potential explanation for this demise is that ferromagnetic fluctuations compete with superconductivity in the overdoped regime. In this case, a ferromagnetic phase at very low temperatures is predicted to exist beyond the doping concentration at which superconductivity disappears. Here we report on a direct examination of this scenario in overdoped La2-xSrxCuO4 using the technique of muon spin relaxation. We detect the onset of static magnetic moments of electronic origin at low temperature in the heavily overdoped nonsuperconducting region. However, the magnetism does not exist in a commensurate long-range ordered state. Instead it appears as a dilute concentration of static magnetic moments. This finding places severe restrictions on the form of ferromagnetism that may exist in the overdoped regime. Although an extrinsic impurity cannot be absolutely ruled out as the source of the magnetism that does occur, the results presented here lend support to electronic band calculations that predict the occurrence of weak localized ferromagnetism at high doping.

Sonier, J. E.; Kaiser, C. V.; Pacradouni, V.; Sabok-Sayr, S. A.; Cochrane, C.; MacLaughlin, D. E.; Komiya, S.; Hussey, N. E.

2010-01-01

200

Duplex interrogation by a direct DNA repair protein in search of base damage  

SciTech Connect

ALKBH2 is a direct DNA repair dioxygenase guarding the mammalian genome against N{sup 1}-methyladenine, N{sup 3}-methylcytosine and 1,N{sup 6}-ethenoadenine damage. A prerequisite for repair is to identify these lesions in the genome. Here we present crystal structures of human ALKBH2 bound to different duplex DNAs. Together with computational and biochemical analyses, our results suggest that DNA interrogation by ALKBH2 has two previously unknown features: (i) ALKBH2 probes base-pair stability and detects base pairs with reduced stability, and (ii) ALKBH2 does not have nor need a damage-checking site, which is critical for preventing spurious base cleavage for several glycosylases. The demethylation mechanism of ALKBH2 insures that only cognate lesions are oxidized and reversed to normal bases, and that a flipped, non-substrate base remains intact in the active site. Overall, the combination of duplex interrogation and oxidation chemistry allows ALKBH2 to detect and process diverse lesions efficiently and correctly.

Yi, Chengqi; Chen, Baoen; Qi, Bo; Zhang, Wen; Jia, Guifang; Zhang, Liang; Li, Charles J.; Dinner, Aaron R.; Yang, Cai-Guang; He, Chuan (Peking); (Chinese Aca. Sci.); (UC)

2012-08-31

201

Icarus: A 2D direct simulation Monte Carlo (DSMC) code for parallel computers. User`s manual - V.3.0  

SciTech Connect

Icarus is a 2D Direct Simulation Monte Carlo (DSMC) code which has been optimized for the parallel computing environment. The code is based on the DSMC method of Bird and models from free-molecular to continuum flowfields in either cartesian (x, y) or axisymmetric (z, r) coordinates. Computational particles, representing a given number of molecules or atoms, are tracked as they have collisions with other particles or surfaces. Multiple species, internal energy modes (rotation and vibration), chemistry, and ion transport are modelled. A new trace species methodology for collisions and chemistry is used to obtain statistics for small species concentrations. Gas phase chemistry is modelled using steric factors derived from Arrhenius reaction rates. Surface chemistry is modelled with surface reaction probabilities. The electron number density is either a fixed external generated field or determined using a local charge neutrality assumption. Ion chemistry is modelled with electron impact chemistry rates and charge exchange reactions. Coulomb collision cross-sections are used instead of Variable Hard Sphere values for ion-ion interactions. The electrostatic fields can either be externally input or internally generated using a Langmuir-Tonks model. The Icarus software package includes the grid generation, parallel processor decomposition, postprocessing, and restart software. The commercial graphics package, Tecplot, is used for graphics display. The majority of the software packages are written in standard Fortran.

Bartel, T.; Plimpton, S.; Johannes, J.; Payne, J.

1996-10-01

202

SpoIIIE mechanism of directional translocation involves target search coupled to sequence-dependent motor stimulation  

PubMed Central

SpoIIIE/FtsK are membrane-anchored, ATP-fuelled, directional motors responsible for chromosomal segregation in bacteria. Directionality in these motors is governed by interactions between specialized sequence-recognition modules (SpoIIIE-?/FtsK-?) and highly skewed chromosomal sequences (SRS/KOPS). Using a new combination of ensemble and single-molecule methods, we dissect the series of steps required for SRS localization and motor activation. First, we demonstrate that SpoIIIE/DNA association kinetics are sequence independent, with binding specificity being uniquely determined by dissociation. Next, we show by single-molecule and modelling methods that hexameric SpoIIIE binds DNA non-specifically and finds SRS by an ATP-independent target search mechanism, with ensuing oligomerization and binding of SpoIIIE-? to SRS triggering motor stimulation. Finally, we propose a new model that provides an entirely new interpretation of previous observations for the origin of SRS/KOPS-directed translocation by SpoIIIE/FtsK.

Cattoni, Diego I; Chara, Osvaldo; Godefroy, Cedric; Margeat, Emmanuel; Trigueros, Sonia; Milhiet, Pierre-Emmanuel; Nollmann, Marcelo

2013-01-01

203

Measurement and modeling of muon-induced neutrons in LSM in application for direct dark matter searches  

SciTech Connect

Due to a very low event rate expected in direct dark matter search experiments, a good understanding of every background component is crucial. Muon-induced neutrons constitute a prominent background, since neutrons lead to nuclear recoils and thus can mimic a potential dark matter signal. EDELWEISS is a Ge-bolometer experiment searching for WIMP dark matter. It is located in the Laboratoire Souterrain de Modane (LSM, France). We have measured muon-induced neutrons by means of a neutron counter based on Gd-loaded liquid scintillator. Studies of muon-induced neutrons are presented and include development of the appropriate MC model based on Geant4 and analysis of a 1000-days measurement campaign in LSM. We find a good agreement between measured rates of muon-induced neutrons and those predicted by the developed model with full event topology. The impact of the neutron background on current EDELWEISS data-taking as well as for next generation experiments such as EURECA is briefly discussed.

Kozlov, Valentin [Karlsruhe Institute of Technology, Institut für Kernphysik, Postfach 3640, 76021 Karlsruhe (Germany)] [Karlsruhe Institute of Technology, Institut für Kernphysik, Postfach 3640, 76021 Karlsruhe (Germany); Collaboration: EDELWEISS Collaboration

2013-08-08

204

Measurement and modeling of muon-induced neutrons in LSM in application for direct dark matter searches  

NASA Astrophysics Data System (ADS)

Due to a very low event rate expected in direct dark matter search experiments, a good understanding of every background component is crucial. Muon-induced neutrons constitute a prominent background, since neutrons lead to nuclear recoils and thus can mimic a potential dark matter signal. EDELWEISS is a Ge-bolometer experiment searching for WIMP dark matter. It is located in the Laboratoire Souterrain de Modane (LSM, France). We have measured muon-induced neutrons by means of a neutron counter based on Gd-loaded liquid scintillator. Studies of muon-induced neutrons are presented and include development of the appropriate MC model based on Geant4 and analysis of a 1000-days measurement campaign in LSM. We find a good agreement between measured rates of muon-induced neutrons and those predicted by the developed model with full event topology. The impact of the neutron background on current EDELWEISS data-taking as well as for next generation experiments such as EURECA is briefly discussed.

Kozlov, Valentin; EDELWEISS Collaboration

2013-08-01

205

Searches for Direct CP Violation in D+ Decays And for D0 Anti-D0 Mixing  

SciTech Connect

The authors present preliminary results of a search for direct CP violation in D{sup +} {yields} K{sup +}K{sup -} {pi}{sup +} decays using 87 fb{sup -1} of data acquired by the Babar experiment running on and near the {Upsilon}(4S) from 1999-2002. The authors report the asymmetries in the signal mode and in the main resonant subchannels. Based on the same dataset, they also report a new 90% CL upper limit of 0.0042 on the rate of D{sup 0}-{bar D}{sup 0} mixing using the decay modes D*{sup +} {yields} D{sup 0}{pi}{sup +}, D{sup 0} {yields} [K/K*]ev (+c.c.).

Purohit, M.V.; /South Carolina U.

2005-10-11

206

Identification of Unknown Interface Locations in a Source/Shield System Using the Mesh Adaptive Direct Search Method  

SciTech Connect

The Levenberg-Marquardt (or simply Marquardt) and differential evolution (DE) optimization methods were recently applied to solve inverse transport problems. The Marquardt method is fast but convergence of the method is dependent on the initial guess. While it has been shown to work extremely well at finding an optimum independent of the initial guess, the DE method does not provide a global optimal solution in some problems. In this paper, we apply the Mesh Adaptive Direct Search (MADS) algorithm to solve the inverse problem of material interface location identification in one-dimensional spherical radiation source/shield systems, and we compare the results obtained by MADS to those obtained by Levenberg-Marquardt and DE.

Armstrong, Jerawan C. [Los Alamos National Laboratory; Favorite, Jeffrey A. [Los Alamos National Laboratory

2012-06-20

207

A Massively Parallel Hybrid Dusty-Gasdynamics and Kinetic Direct Simulation Monte Carlo Model for Planetary Applications  

NASA Technical Reports Server (NTRS)

In order to understand the global structure, dynamics, and physical and chemical processes occurring in the upper atmospheres, exospheres, and ionospheres of the Earth, the other planets, comets and planetary satellites and their interactions with their outer particles and fields environs, it is often necessary to address the fundamentally non-equilibrium aspects of the physical environment. These are regions where complex chemistry, energetics, and electromagnetic field influences are important. Traditional approaches are based largely on hydrodynamic or magnetohydrodynamic (MHD) formulations and are very important and highly useful. However, these methods often have limitations in rarefied physical regimes where the molecular collision rates and ion gyrofrequencies are small and where interactions with ionospheres and upper neutral atmospheres are important. At the University of Michigan we have an established base of experience and expertise in numerical simulations based on particle codes which address these physical regimes. The Principal Investigator, Dr. Michael Combi, has over 20 years of experience in the development of particle-kinetic and hybrid kinetichydrodynamics models and their direct use in data analysis. He has also worked in ground-based and space-based remote observational work and on spacecraft instrument teams. His research has involved studies of cometary atmospheres and ionospheres and their interaction with the solar wind, the neutral gas clouds escaping from Jupiter s moon Io, the interaction of the atmospheres/ionospheres of Io and Europa with Jupiter s corotating magnetosphere, as well as Earth s ionosphere. This report describes our progress during the year. The contained in section 2 of this report will serve as the basis of a paper describing the method and its application to the cometary coma that will be continued under a research and analysis grant that supports various applications of theoretical comet models to understanding the inner comae of comets (grant NAGS- 13239 from the Planetary Atmospheres program).

Combi, Michael R.

2004-01-01

208

Parallel Rendering.  

National Technical Information Service (NTIS)

This article provides a broad introduction to the subject of parallel rendering, encompassing both hardware and software systems. The focus is on the underlying concepts and the issues which arise in the design of parallel rendering algorithms and systems...

T. W. Crockett

1995-01-01

209

Parallel processing  

SciTech Connect

This report examines the current techniques of parallel processing, transputers, vector and vector supercomputers and covers such areas as transputer applications, programming models and language design for parallel processing.

Jesshop, C.

1987-01-01

210

Simulated annealing and metaheuristic for randomized priority search algorithms for the aerial refuelling parallel machine scheduling problem with due date-to-deadline windows and release times  

Microsoft Academic Search

This article addresses the aerial refuelling scheduling problem (ARSP), where a set of fighter jets (jobs) with certain ready times must be refuelled from tankers (machines) by their due dates; otherwise, they reach a low fuel level (deadline) incurring a high cost. ARSP is an identical parallel machine scheduling problem with release times and due date-to-deadline windows to minimize the

Sezgin Kaplan; Ghaith Rabadi

2012-01-01

211

Parallel encrypted array multipliers  

SciTech Connect

An algorithm for direct two's-complement and sign-magnitude parallel multiplication is described. The partial product matrix representing the multiplication is converted to an equivalent matrix by encryption. Its reduction, producing the final result, needs no specialized adders and can be added with any parallel array addition technique. It contains no negative terms and no extra ''correction'' rows; in addition, it produces the multiplication with fewer than the minimal number of rows required for a direct multiplication process.

Vassiliadis, S.; Putrino, M.; Schwarz, E.M.

1988-07-01

212

Serial, Covert Shifts of Attention during Visual Search Are Reflected by the Frontal Eye Fields and Correlated with Population Oscillations  

Microsoft Academic Search

SUMMARY Attention regulates the flood of sensory information into a manageable stream, and so understanding howattentioniscontrollediscentraltounderstanding cognition. Competing theories suggest visual search involves serial and\\/or parallel allocation of attention, but there is little direct, neural evidence for either mechanism. Two monkeys were trained to covertly search an array for a target stimulus under visual search (endogenous) and pop-out (exogenous) con-

Timothy J. Buschman; Earl K. Miller

2009-01-01

213

Parallel rendering  

NASA Technical Reports Server (NTRS)

This article provides a broad introduction to the subject of parallel rendering, encompassing both hardware and software systems. The focus is on the underlying concepts and the issues which arise in the design of parallel rendering algorithms and systems. We examine the different types of parallelism and how they can be applied in rendering applications. Concepts from parallel computing, such as data decomposition, task granularity, scalability, and load balancing, are considered in relation to the rendering problem. We also explore concepts from computer graphics, such as coherence and projection, which have a significant impact on the structure of parallel rendering algorithms. Our survey covers a number of practical considerations as well, including the choice of architectural platform, communication and memory requirements, and the problem of image assembly and display. We illustrate the discussion with numerous examples from the parallel rendering literature, representing most of the principal rendering methods currently used in computer graphics.

Crockett, Thomas W.

1995-01-01

214

A search for anisotropy in the arrival directions of ultra high energy cosmic rays recorded at the Pierre Auger Observatory  

SciTech Connect

Observations of cosmic ray arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects drawn from the Veron-Cetty Veron catalog. In this paper we report on the use of three catalog independent methods to search for anisotropy. The 2pt-L, 2pt+ and 3pt methods, each giving a different measure of self-clustering in arrival directions, were tested on mock cosmic ray data sets to study the impacts of sample size and magnetic smearing on their results, accounting for both angular and energy resolutions. If the sources of UHECRs follow the same large scale structure as ordinary galaxies in the local Universe and if UHECRs are deflected no more than a few degrees, a study of mock maps suggests that these three methods can efficiently respond to the resulting anisotropy with a P-value = 1.0% or smaller with data sets as few as 100 events. Using data taken from January 1, 2004 to July 31, 2010 we examined the 20, 30, ..., 110 highest energy events with a corresponding minimum energy threshold of about 51 EeV. The minimum P-values found were 13.5% using the 2pt-L method, 1.0% using the 2pt+ method and 1.1% using the 3pt method for the highest 100 energy events. In view of the multiple (correlated) scans performed on the data set, these catalog-independent methods do not yield strong evidence of anisotropy in the highest energy cosmic rays.

Abreu, P.

2012-01-01

215

Parallel Algorithms  

NSDL National Science Digital Library

Content prepared for the Supercomputing 2002 session on "Using Clustering Technologies in the Classroom". Contains a series of exercises for teaching parallel computing concepts through kinesthetic activities.

Gray, Paul

216

Universal approximators for multi-objective direct policy search in water reservoir management problems: a comparative analysis  

NASA Astrophysics Data System (ADS)

The optimal operation of water resources systems is a wide and challenging problem due to non-linearities in the model and the objectives, high dimensional state-control space, and strong uncertainties in the hydroclimatic regimes. The application of classical optimization techniques (e.g., SDP, Q-learning, gradient descent-based algorithms) is strongly limited by the dimensionality of the system and by the presence of multiple, conflicting objectives. This study presents a novel approach which combines Direct Policy Search (DPS) and Multi-Objective Evolutionary Algorithms (MOEAs) to solve high-dimensional state and control space problems involving multiple objectives. DPS, also known as parameterization-simulation-optimization in the water resources literature, is a simulation-based approach where the reservoir operating policy is first parameterized within a given family of functions and, then, the parameters optimized with respect to the objectives of the management problem. The selection of a suitable class of functions to which the operating policy belong to is a key step, as it might restrict the search for the optimal policy to a subspace of the decision space that does not include the optimal solution. In the water reservoir literature, a number of classes have been proposed. However, many of these rules are based largely on empirical or experimental successes and they were designed mostly via simulation and for single-purpose reservoirs. In a multi-objective context similar rules can not easily inferred from the experience and the use of universal function approximators is generally preferred. In this work, we comparatively analyze two among the most common universal approximators: artificial neural networks (ANN) and radial basis functions (RBF) under different problem settings to estimate their scalability and flexibility in dealing with more and more complex problems. The multi-purpose HoaBinh water reservoir in Vietnam, accounting for hydropower production and flood control, is used as a case study. Preliminary results show that the RBF policy parametrization is more effective than the ANN one. In particular, the approximated Pareto front obtained with RBF control policies successfully explores the full tradeoff space between the two conflicting objectives, while most of the ANN solutions results to be Pareto-dominated by the RBF ones.

Giuliani, Matteo; Mason, Emanuele; Castelletti, Andrea; Pianosi, Francesca

2014-05-01

217

Parallel Optimisation  

NSDL National Science Digital Library

An introduction to optimisation techniques that may improve parallel performance and scaling on HECToR. It assumes that the reader has some experience of parallel programming including basic MPI and OpenMP. Scaling is a measurement of the ability for a parallel code to use increasing numbers of cores efficiently. A scalable application is one that, when the number of processors is increased, performs better by a factor which justifies the additional resource employed. Making a parallel application scale to many thousands of processes requires not only careful attention to the communication, data and work distribution but also to the choice of the algorithms to use. Since the choice of algorithm is too broad a subject and very particular to application domain to include in this brief guide we concentrate on general good practices towards parallel optimisation on HECToR.

218

PSSA: Parallel Stretched Simulated Annealing  

NASA Astrophysics Data System (ADS)

We consider the problem of finding all the global (and some local) minimizers of a given nonlinear optimization function (a class of problems also known as multi-local programming problems), using a novel approach based on Parallel Computing. The approach, named Parallel Stretched Simulated Annealing (PSSA), combines simulated annealing with stretching function technique, in a parallel execution environment. Our PSSA software allows to increase the resolution of the search domains (thus facilitating the discovery of new solutions) while keeping the search time bounded. The software was tested with a set of well known problems and some numerical results are presented.

Ribeiro, Tiago; Rufino, José; Pereira, Ana I.

2011-09-01

219

Attentional Limitations in the Sensing of Motion Direction  

Microsoft Academic Search

Attentional constraints in the perceptual analysis of motion direction were examined using two independent paradigms: redundant target visual search and the analysis of fluctuations in discrimination accuracy at threshold. Results from both methods implied that directions of object motion are analyzed in parallel when those motions are translations, independent of the observer's line of sight. The registration of rotation direction

Thomas Thornton; David L. Gilden

2001-01-01

220

Transverse electron polarization in the neutron decay - Direct search for scalar and tensor couplings in weak interaction  

NASA Astrophysics Data System (ADS)

The Standard Model (SM) predictions of T-violation for weak decays of systems built up of u and d quarks are by 7 to 10 orders of magnitude lower than the experimental accuracies attainable at present. It is a general presumption that time reversal phenomena are caused by a tiny admixture of exotic interaction terms. Therefore, weak decays provide a favorable testing ground in a search for such feeble forces. Physics with very slow, polarized neutrons has a great potential in this respect. An experiment seeking for small deviations from the SM in two observables, N and R, that are for the first time addressed experimentally in free neutron decay and that are exclusively sensitive to real and imaginary parts of the same linear combination of the scalar and tensor interaction coupling constants has been completed at the Paul Scherrer Institute, Villigen, Switzerland. The analysis of the experimental data has been completed recently leading to, among others, the best direct constraint for the imaginary part of the R-parity violating MSSM contribution. The success of the applied technique results in a new project devoted to the simultaneous measurement of seven correlation coefficients: H, L, N, R, S, U and V. Five of them (H, L, S, U and V) have never before been measured in weak decays. Such a systematic exploration of the transverse electron polarization will generate from the neutron decay alone a complete set of constraints for the real and imaginary parts of the weak scalar and tensor interactions on the level of 5 × 10-4 or better.

Bodek, Kazimierz

2012-04-01

221

Parallel biocomputing  

PubMed Central

Background With the advent of high throughput genomics and high-resolution imaging techniques, there is a growing necessity in biology and medicine for parallel computing, and with the low cost of computing, it is now cost-effective for even small labs or individuals to build their own personal computation cluster. Methods Here we briefly describe how to use commodity hardware to build a low-cost, high-performance compute cluster, and provide an in-depth example and sample code for parallel execution of R jobs using MOSIX, a mature extension of the Linux kernel for parallel computing. A similar process can be used with other cluster platform software. Results As a statistical genetics example, we use our cluster to run a simulated eQTL experiment. Because eQTL is computationally intensive, and is conceptually easy to parallelize, like many statistics/genetics applications, parallel execution with MOSIX gives a linear speedup in analysis time with little additional effort. Conclusions We have used MOSIX to run a wide variety of software programs in parallel with good results. The limitations and benefits of using MOSIX are discussed and compared to other platforms.

2011-01-01

222

Parallel machines: Parallel machine languages  

SciTech Connect

This book presents a framework for understanding the tradeoffs between the conventional view and the dataflow view with the objective of discovering the critical hardware structures which must be present in any scalable, general-purpose parallel computer to effectively tolerate latency and synchronization costs. The author presents an approach to scalable general purpose parallel computation. Linguistic Concerns, Compiling Issues, Intermediate Language Issues, and hardware/technological constraints are presented as a combined approach to architectural Develoement. This book presents the notion of a parallel machine language.

Iannucci, R.A. (IBM (US))

1990-01-01

223

Do We Step Together, in the Same Direction, at the Same Time? How a Consortium Approached a Federated Search Implementation  

Microsoft Academic Search

The Five College Libraries of Western Massachusetts have a long-standing tradition of collaborating on technology projects which improve our communities' access to information resources. After investigating various link resolver and federated search products in 2002, the Five College Librarians' Council signed a three-year contract with Ex Libris in spring 2003 to host SFX link resolver and MetaLib federated search installations.

Lori S. Mestre; Christine Turner; Beth Lang; Barbara Morgan

2007-01-01

224

Automatic Multilevel Parallelization Using OpenMP  

NASA Technical Reports Server (NTRS)

In this paper we describe the extension of the CAPO (CAPtools (Computer Aided Parallelization Toolkit) OpenMP) parallelization support tool to support multilevel parallelism based on OpenMP directives. CAPO generates OpenMP directives with extensions supported by the NanosCompiler to allow for directive nesting and definition of thread groups. We report some results for several benchmark codes and one full application that have been parallelized using our system.

Jin, Hao-Qiang; Jost, Gabriele; Yan, Jerry; Ayguade, Eduard; Gonzalez, Marc; Martorell, Xavier; Biegel, Bryan (Technical Monitor)

2002-01-01

225

Parallel thinking  

Microsoft Academic Search

Assuming that the multicore revolution plays out the way the microprocessor industry expects, it seems that within a decade most programming will involve parallelism at some level. One needs to ask how this affects the the way we teach computer science, or even how we have people think about computation. With regards to teaching there seem to be three basic

Guy E. Blelloch

2009-01-01

226

Determining the Propagation Direction and Velocity of Pc 1-2 Waves using Search Coil Magnetometers on Svalbard  

Microsoft Academic Search

Electromagnetic ion cyclotron (EMIC) waves observed by ground-based arrays of search coil magnetometers can provide remote diagnostics of plasma processes in Earth's magnetosphere. Horizontal ducting of these waves in the ionosphere, however, makes it difficult to locate the magnetic latitude at which such waves are generated. We have used data since August 2008 from a closely-spaced two-dimensional array of four

D. Nguyen; M. Engebretson; J. L. Posch; M. Lessard; D. M. Wright

2010-01-01

227

Direct Exoplanet\\/Disk Search Around Young & Nearby Early-Type Stars; The International Deep Planet Survey (IDPS)  

Microsoft Academic Search

We propose to continue a deep AO survey for exoplanets around young and close A- and F-type stars using a refined version of the very successful Angular Differential Imaging technique, which distinguishes true companions\\/disks from artifacts through sidereal rotation. Stars as massive as A- and early F-type stars have been neglected in AO searches, including the Gemini Deep Planet Survey,

Christian Marois; Bruce Macintosh; Jennifer Patience; Rene Doyon; Benjamin Zuckerman; Inseok Song; David Lafreniere; Travis Barman

2008-01-01

228

Analytic Guided-Search Model of Human Performance Accuracy in Target- Localization Search Tasks  

NASA Technical Reports Server (NTRS)

Current models of human visual search have extended the traditional serial/parallel search dichotomy. Two successful models for predicting human visual search are the Guided Search model and the Signal Detection Theory model. Although these models are inherently different, it has been difficult to compare them because the Guided Search model is designed to predict response time, while Signal Detection Theory models are designed to predict performance accuracy. Moreover, current implementations of the Guided Search model require the use of Monte-Carlo simulations, a method that makes fitting the model's performance quantitatively to human data more computationally time consuming. We have extended the Guided Search model to predict human accuracy in target-localization search tasks. We have also developed analytic expressions that simplify simulation of the model to the evaluation of a small set of equations using only three free parameters. This new implementation and extension of the Guided Search model will enable direct quantitative comparisons with human performance in target-localization search experiments and with the predictions of Signal Detection Theory and other search accuracy models.

Eckstein, Miguel P.; Beutter, Brent R.; Stone, Leland S.

2000-01-01

229

Applied Parallel Metadata Indexing  

SciTech Connect

The GPFS Archive is parallel archive is a parallel archive used by hundreds of users in the Turquoise collaboration network. It houses 4+ petabytes of data in more than 170 million files. Currently, users must navigate the file system to retrieve their data, requiring them to remember file paths and names. A better solution might allow users to tag data with meaningful labels and searach the archive using standard and user-defined metadata, while maintaining security. last summer, I developed the backend to a tool that adheres to these design goals. The backend works by importing GPFS metadata into a MongoDB cluster, which is then indexed on each attribute. This summer, the author implemented security and developed the user interfae for the search tool. To meet security requirements, each database table is associated with a single user, which only stores records that the user may read, and requires a set of credentials to access. The interface to the search tool is implemented using FUSE (Filesystem in USErspace). FUSE is an intermediate layer that intercepts file system calls and allows the developer to redefine how those calls behave. In the case of this tool, FUSE interfaces with MongoDB to issue queries and populate output. A FUSE implementation is desirable because it allows users to interact with the search tool using commands they are already familiar with. These security and interface additions are essential for a usable product.

Jacobi, Michael R [Los Alamos National Laboratory

2012-08-01

230

SearchPad: explicit capture of search context to support Web search  

Microsoft Academic Search

Experienced users who query search engines have a complex behavior. They explore many topics in parallel, experiment with query variations, consult multiple search engines, and gather information over many sessions. In the process they need to keep track of search context — namely useful queries and promising result links, which can be hard. We present an extension to search engines

Krishna Bharat

2000-01-01

231

Discovering Common Ground: How Future Search Conferences Bring People Together To Achieve Breakthrough Innovation, Empowerment, Shared Vision, and Collaborative Action.  

ERIC Educational Resources Information Center

This book contains 35 papers about planning and holding future search conferences, as well as their benefits and likely future directions. The following papers are included: "Applied Common Sense" (Weisbord); "Inventing the Search Conference" (Weisbord); "Building Collaborative Communities" (Schindler-Rainman, Lippitt); "Parallel Paths to…

Weisbord, Marvin R.; And Others

232

Direct search for Dirac magnetic monopoles in pp collisions at square root s = 1.96 TeV.  

PubMed

We search for pair-produced Dirac magnetic monopoles in 35.7 pb(-1) of proton-antiproton collisions at square root s = 1.96 TeV with the Collider Detector at Fermilab (CDF). We find no monopole candidates corresponding to a 95% confidence-level cross-section limit sigma < 0.2 pb for a monopole with mass between 200 and 700 GeV/c2. Assuming a Drell-Yan pair-production mechanism, we set a mass limit m > 360 GeV/c2. PMID:16803165

Abulencia, A; Acosta, D; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Ambrose, D; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arguin, J-F; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Bachacou, H; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Bedeschi, F; Behari, S; Belforte, S; Bellettini, G; Bellinger, J; Belloni, A; Ben-Haim, E; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bishai, M; Blair, R E; Blocker, C; Bloom, K; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Bourov, S; Boveia, A; Brau, B; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carlsmith, D; Carosi, R; Carron, S; Carter, A; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chapman, J; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Chu, P H; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciljak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Connolly, A; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Cruz, A; Cuevas, J; Culbertson, R; Cyr, D; DaRonco, S; D'Auria, S; D'Onofrio, M; Dagenhart, D; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; Dell'Orso, M; Demers, S; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Dionisi, C; Dittmann, J; DiTuro, P; Dörr, C; Dominguez, A; Donati, S; Donega, M; Dong, P; Donini, J; Dorigo, T; Dube, S; Ebina, K; Efron, J; Ehlers, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Flores-Castillo, L R; Foland, A; Forrester, S; Foster, G W; Franklin, M; Freeman, J C; Fujii, Y; Furic, I; Gajjar, A; Gallinaro, M; Galyardt, J; Garcia, J E; Garcia Sciverez, M; Garfinkel, A F; Gay, C; Gerberich, H; Gerchtein, E; Gerdes, D; Giagu, S; Giannetti, P; Gibson, A; Gibson, K; Ginsburg, C; Giolo, K; Giordani, M; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Gotra, Y; Goulianos, K; Gresele, A; Griffiths, M; Grinstein, S; Grosso-Pilcher, C; Grundler, U; da Costa, J Guimaraes; Haber, C; Hahn, S R; Hahn, K; Halkiadakis, E; Hamilton, A; Han, B-Y; Handler, R; Happacher, F; Hara, K; Hare, M; Harper, S; Harr, R F; Harris, R M; Hatakeyama, K; Hauser, J; Hays, C; Hayward, H; Heijboer, A; Heinemann, B; Heinrich, J; Hennecke, M; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Huston, J; Ikado, K; Incandela, J; Introzzi, G; Iori, M; Ishizawa, Y; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jensen, H; Jeon, E J; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kamon, T; Kang, J; Karagoz-Unel, M; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, M S; Kim, S B; Kim, S H; Kim, Y K; Kirby, M; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kobayashi, H; Kondo, K; Kong, D J; Konigsberg, J; Kordas, K; Korytov, A; Kotwal, A V; Kovalev, A; Kraus, J; Kravchenko, I; Kreps, M; Kreymer, A; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kuhlmann, S E; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecci, C; LeCompte, T; Lee, J; Lee, J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Li, K; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Liss, T M; Lister, A; Litvintsev, D O; Liu, T; Liu, Y; Lockyer, N S; Loginov, A; Loreti, M; Loverre, P; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; MacQueen, D; Madrak, R; Maeshima, K; Maksimovic, P; Manca, G; Margaroli, F; Marginean, R; Marino, C; Martin, A; Martin, M; Martin, V; Martínez, M; Maruyama, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McGivern, D; McIntyre, P; McNamara, P; McNulty, R; Mehta, A; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; von der Mey, M; Miao, T; Miladinovic, N; Miles, J; Miller, R; Miller, J S; Mills, C; Milnik, M; Miquel, R; Miscetti, S; Mitselmakher, G; Miyamoto, A; Moggi, N; Mohr, B; Moore, R; Morello, M; Fernandez, P Movilla; Mülmenstädt, J; Mukherjee, A; Mulhearn, M; Muller, Th; Mumford, R; Murat, P; Nachtman, J; Nahn, S; Nakano, I; Napier, A; Naumov, D; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nigmanov, T; Nodulman, L; Norniella, O

2006-05-26

233

Direct Search for Dirac Magnetic Monopoles in pp¯ Collisions at s=1.96TeV  

Microsoft Academic Search

We search for pair-produced Dirac magnetic monopoles in 35.7pb-1 of proton-antiproton collisions at s=1.96TeV with the Collider Detector at Fermilab (CDF). We find no monopole candidates corresponding to a 95% confidence-level cross-section limit sigma<0.2pb for a monopole with mass between 200 and 700GeV\\/c2. Assuming a Drell-Yan pair-production mechanism, we set a mass limit m>360GeV\\/c2.

A. Abulencia; D. Acosta; J. Adelman; T. Affolder; T. Akimoto; M. G. Albrow; D. Ambrose; S. Amerio; D. Amidei; A. Anastassov; K. Anikeev; A. Annovi; J. Antos; M. Aoki; G. Apollinari; J.-F. Arguin; T. Arisawa; A. Artikov; W. Ashmanskas; A. Attal; F. Azfar; P. Azzi-Bacchetta; P. Azzurri; N. Bacchetta; H. Bachacou; W. Badgett; A. Barbaro-Galtieri; V. E. Barnes; B. A. Barnett; S. Baroiant; V. Bartsch; G. Bauer; F. Bedeschi; S. Behari; S. Belforte; G. Bellettini; J. Bellinger; A. Belloni; E. Ben-Haim; D. Benjamin; A. Beretvas; J. Beringer; T. Berry; A. Bhatti; M. Binkley; D. Bisello; M. Bishai; R. E. Blair; C. Blocker; K. Bloom; B. Blumenfeld; A. Bocci; A. Bodek; V. Boisvert; G. Bolla; A. Bolshov; D. Bortoletto; J. Boudreau; S. Bourov; A. Boveia; B. Brau; C. Bromberg; E. Brubaker; J. Budagov; H. S. Budd; S. Budd; K. Burkett; G. Busetto; P. Bussey; K. L. Byrum; S. Cabrera; M. Campanelli; M. Campbell; F. Canelli; A. Canepa; D. Carlsmith; R. Carosi; S. Carron; A. Carter; M. Casarsa; A. Castro; P. Catastini; D. Cauz; M. Cavalli-Sforza; A. Cerri; L. Cerrito; S. H. Chang; J. Chapman; Y. C. Chen; M. Chertok; G. Chiarelli; G. Chlachidze; F. Chlebana; I. Cho; K. Cho; D. Chokheli; J. P. Chou; P. H. Chu; S. H. Chuang; K. Chung; W. H. Chung; Y. S. Chung; M. Ciljak; C. I. Ciobanu; M. A. Ciocci; A. Clark; D. Clark; M. Coca; A. Connolly; M. E. Convery; J. Conway; B. Cooper; K. Copic; M. Cordelli; G. Cortiana; A. Cruz; J. Cuevas; R. Culbertson; D. Cyr; S. Daronco; S. D'Auria; M. D'Onofrio; D. Dagenhart; P. de Barbaro; S. de Cecco; A. Deisher; G. de Lentdecker; M. Dell'Orso; S. Demers; L. Demortier; J. Deng; M. Deninno; D. de Pedis; P. F. Derwent; C. Dionisi; J. Dittmann; P. Dituro; C. Dörr; A. Dominguez; S. Donati; M. Donega; P. Dong; J. Donini; T. Dorigo; S. Dube; K. Ebina; J. Efron; J. Ehlers; R. Erbacher; D. Errede; S. Errede; R. Eusebi; H. C. Fang; S. Farrington; I. Fedorko; W. T. Fedorko; R. G. Feild; M. Feindt; J. P. Fernandez; R. Field; G. Flanagan; L. R. Flores-Castillo; A. Foland; S. Forrester; G. W. Foster; M. Franklin; J. C. Freeman; Y. Fujii; I. Furic; A. Gajjar; M. Gallinaro; J. Galyardt; J. E. Garcia; M. Garcia Sciverez; A. F. Garfinkel; C. Gay; H. Gerberich; E. Gerchtein; D. Gerdes; S. Giagu; P. Giannetti; A. Gibson; K. Gibson; C. Ginsburg; K. Giolo; M. Giordani; M. Giunta; G. Giurgiu; V. Glagolev; D. Glenzinski; M. Gold; N. Goldschmidt; J. Goldstein; G. Gomez; G. Gomez-Ceballos; M. Goncharov; O. González; I. Gorelov; A. T. Goshaw; Y. Gotra; K. Goulianos; A. Gresele; M. Griffiths; S. Grinstein; C. Grosso-Pilcher; U. Grundler; J. Guimaraes da Costa; C. Haber; S. R. Hahn; K. Hahn; E. Halkiadakis; B.-Y. Han; R. Handler; F. Happacher; K. Hara; M. Hare; S. Harper; R. F. Harr; R. M. Harris; K. Hatakeyama; J. Hauser; C. Hays; H. Hayward; A. Heijboer; B. Heinemann; J. Heinrich; M. Hennecke; M. Herndon; J. Heuser; D. Hidas; C. S. Hill; D. Hirschbuehl; A. Hocker; A. Holloway; S. Hou; M. Houlden; S.-C. Hsu; B. T. Huffman; R. E. Hughes; J. Huston; K. Ikado; J. Incandela; G. Introzzi; M. Iori; Y. Ishizawa; A. Ivanov; B. Iyutin; E. James; D. Jang; B. Jayatilaka; D. Jeans; H. Jensen; E. J. Jeon; M. Jones; K. K. Joo; S. Y. Jun; T. R. Junk; T. Kamon; J. Kang; M. Karagoz-Unel; P. E. Karchin; Y. Kato; Y. Kemp; R. Kephart; U. Kerzel; V. Khotilovich; B. Kilminster; D. H. Kim; H. S. Kim; J. E. Kim; M. J. Kim; S. B. Kim; S. H. Kim; Y. K. Kim; M. Kirby; L. Kirsch; S. Klimenko; M. Klute; B. Knuteson; B. R. Ko; H. Kobayashi; K. Kondo; D. J. Kong; J. Konigsberg; K. Kordas; A. Korytov; A. V. Kotwal; A. Kovalev; J. Kraus; I. Kravchenko; M. Kreps; A. Kreymer; J. Kroll; N. Krumnack; M. Kruse; V. Krutelyov; S. E. Kuhlmann; Y. Kusakabe; S. Kwang; A. T. Laasanen; S. Lai; S. Lami; S. Lammel; M. Lancaster; R. L. Lander; K. Lannon; A. Lath; G. Latino; I. Lazzizzera; C. Lecci; T. Lecompte; J. Lee; S. W. Lee; R. Lefèvre; N. Leonardo; S. Leone; S. Levy; J. D. Lewis; K. Li; C. Lin; M. Lindgren; E. Lipeles; T. M. Liss; A. Lister; D. O. Litvintsev; T. Liu; Y. Liu; N. S. Lockyer; A. Loginov; M. Loreti; P. Loverre; R.-S. Lu; D. Lucchesi; P. Lujan; P. Lukens; G. Lungu; L. Lyons; J. Lys; R. Lysak; E. Lytken; P. Mack; D. MacQueen; R. Madrak; K. Maeshima; P. Maksimovic; G. Manca; F. Margaroli; R. Marginean; C. Marino; A. Martin; M. Martin; V. Martin; M. Martínez; T. Maruyama; H. Matsunaga; M. E. Mattson; R. Mazini; P. Mazzanti; K. S. McFarland; D. McGivern; P. McIntyre; P. McNamara; R. McNulty; A. Mehta; S. Menzemer; A. Menzione; P. Merkel; C. Mesropian; A. Messina; M. von der Mey; T. Miao; N. Miladinovic; J. Miles; R. Miller; J. S. Miller; C. Mills; M. Milnik; R. Miquel; S. Miscetti; G. Mitselmakher; A. Miyamoto; N. Moggi; B. Mohr; R. Moore; M. Morello; P. Movilla Fernandez; J. Mülmenstädt; A. Mukherjee; M. Mulhearn; Th. Muller; R. Mumford; P. Murat; J. Nachtman; S. Nahn; I. Nakano; A. Napier; D. Naumov; V. Necula; C. Neu; M. S. Neubauer; J. Nielsen

2006-01-01

234

Demonstrating Forces between Parallel Wires.  

ERIC Educational Resources Information Center

Describes a physics demonstration that dramatically illustrates the mutual repulsion (attraction) between parallel conductors using insulated copper wire, wooden dowels, a high direct current power supply, electrical tape, and an overhead projector. (WRM)

Baker, Blane

2000-01-01

235

Parallel hierarchical global illumination  

SciTech Connect

Solving the global illumination problem is equivalent to determining the intensity of every wavelength of light in all directions at every point in a given scene. The complexity of the problem has led researchers to use approximation methods for solving the problem on serial computers. Rather than using an approximation method, such as backward ray tracing or radiosity, the authors have chosen to solve the Rendering Equation by direct simulation of light transport from the light sources. This paper presents an algorithm that solves the Rendering Equation to any desired accuracy, and can be run in parallel on distributed memory or shared memory computer systems with excellent scaling properties. It appears superior in both speed and physical correctness to recent published methods involving bidirectional ray tracing or hybrid treatments of diffuse and specular surfaces. Like progressive radiosity methods, it dynamically refines the geometry decomposition where required, but does so without the excessive storage requirements for ray histories. The algorithm, called Photon, produces a scene which converges to the global illumination solution. This amounts to a huge task for a 1997-vintage serial computer, but using the power of a parallel supercomputer significantly reduces the time required to generate a solution. Currently, Photon can be run on most parallel environments from a shared memory multiprocessor to a parallel supercomputer, as well as on clusters of heterogeneous workstations.

Snell, Q.O.

1997-10-08

236

A Parallel Tempering algorithm for probabilistic sampling and multimodal optimization  

NASA Astrophysics Data System (ADS)

Non-linear inverse problems in the geosciences often involve probabilistic sampling of multimodal density functions or global optimization and sometimes both. Efficient algorithmic tools for carrying out sampling or optimization in challenging cases are of major interest. Here results are presented of some numerical experiments with a technique, known as Parallel Tempering, which originated in the field of computational statistics but is finding increasing numbers of applications in fields ranging from Chemical Physics to Astronomy. To date, experience in use of Parallel Tempering within earth sciences problems is very limited. In this paper, we describe Parallel Tempering and compare it to related methods of Simulated Annealing and Simulated Tempering for optimization and sampling, respectively. A key feature of Parallel Tempering is that it satisfies the detailed balance condition required for convergence of Markov chain Monte Carlo (McMC) algorithms while improving the efficiency of probabilistic sampling. Numerical results are presented on use of Parallel Tempering for trans-dimensional inversion of synthetic seismic receiver functions and also the simultaneous fitting of multiple receiver functions using global optimization. These suggest that its use can significantly accelerate sampling algorithms and improve exploration of parameter space in optimization. Parallel Tempering is a meta-algorithm which may be used together with many existing McMC sampling and direct search optimization techniques. It's generality and demonstrated performance suggests that there is significant potential for applications to both sampling and optimization problems in the geosciences.

Sambridge, Malcolm

2014-01-01

237

Search for exotic decays from low-energy {ital e}{sup +}{ital e}{sup {minus}} direct annihilation  

SciTech Connect

A new exotic-decay candidate is proposed to resolve the orthopositronium decay rate discrepancy. A search has been performed for the process {ital e}{sup +}{ital e}{sup {minus}}{r_arrow}{gamma}+{ital X}{sup 0}, where the {ital X}{sup 0} is a long-lived, low-mass boson that interacts very weakly with matter and has a charge conjugation eigenvalue {ital C}={minus}1. No evidence for the {ital X}{sup 0} has been found in this experiment, with essentially the entire {ital X}{sup 0} mass range from 0.1 to 1 MeV being excluded as the cause of the decay rate discrepancy. Previous results from other experiments are analyzed for sensitivity to this {ital X}{sup 0}.

Skalsey, M.; Conti, R.S. [Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

1995-06-01

238

Parallel Processing and Information Retrieval.  

ERIC Educational Resources Information Center

This issue contains nine articles that provide an overview of trends and research in parallel information retrieval. Topics discussed include network design for text searching; the Connection Machine System; PThomas, an adaptive information retrieval system on the Connection Machine; algorithms for document clustering; and system architecture for…

Rasmussen, Edie M.; And Others

1991-01-01

239

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in = 8 TeV pp collisions with the ATLAS detector  

NASA Astrophysics Data System (ADS)

A search for the direct production of charginos and neutralinos in final states with three leptons and missing transverse momentum is presented. The analysis is based on 20.3 fb-1 of = 8 TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with the Standard Model expectations and limits are set in R-parity-conserving phenomenological Minimal Supersymmetric Standard Models and in simplified supersymmetric models, significantly extending previous results. For simplified supersymmetric models of direct chargino and next-to-lightest neutralino production with decays to lightest neutralino via either all three generations of sleptons, staus only, gauge bosons, or Higgs bosons, and masses are excluded up to 700 GeV, 380 GeV, 345 GeV, or 148 GeV respectively, for a massless . [Figure not available: see fulltext.

Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Khalek, S. Abdel; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmad, A.; Ahmadov, F.; Aielli, G.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Gonzalez, B. Alvarez; Alviggi, M. G.; Amako, K.; Coutinho, Y. Amaral; Amelung, C.; Amidei, D.; Ammosov, V. V.; Santos, S. P. Amor Dos; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Bella, L. Aperio; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Mayes, J. Backus; Badescu, E.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, S.; Balek, P.; Balli, F.; Banas, E.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bannoura, A. A. E.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; da Costa, J. Barreiro Guimarães; Bartoldus, R.; Barton, A. E.; Bartos, P.; Bartsch, V.; Bassalat, A.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, K.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belloni, A.; Beloborodova, O. L.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Garcia, J. A. Benitez; Benjamin, D. P.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Kuutmann, E. Bergeaas; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernard, C.; Bernat, P.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Bessidskaia, O.; Besson, N.; Betancourt, C.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; De Mendizabal, J. Bilbao; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boek, T. T.; Bogaerts, J. A.; Bogdanchikov, A. G.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borri, M.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutouil, S.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Brendlinger, K.; Brennan, A. J.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, G.; Brown, J.; de Renstrom, P. A. Bruckman; Bruncko, D.; Bruneliere, R.

2014-04-01

240

Search for direct top squark pair production in events with a boson, -jets and missing transverse momentum in TeV collisions with the ATLAS detector  

NASA Astrophysics Data System (ADS)

A search is presented for direct top squark pair production using events with at least two leptons including a same-flavour opposite-sign pair with invariant mass consistent with the boson mass, jets tagged as originating from -quarks and missing transverse momentum. The analysis is performed with proton-proton collision data at collected with the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of 20.3 fb. No excess beyond the Standard Model expectation is observed. Interpretations of the results are provided in models based on the direct pair production of the heavier top squark state () followed by the decay to the lighter top squark state () via , and for pair production in natural gauge-mediated supersymmetry breaking scenarios where the neutralino () is the next-to-lightest supersymmetric particle and decays producing a boson and a gravitino () via the process.

Aad, G.; Abbott, B.; Abdallah, J.; Khalek, S. Abdel; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmad, A.; Ahmadov, F.; Aielli, G.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnold, H.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Backus Mayes, J.; Badescu, E.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, S.; Balek, P.; Balli, F.; Banas, E.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bannoura, A. A. E.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Guimarães da Costa, J. Barreiro; Bartoldus, R.; Barton, A. E.; Bartos, P.; Bartsch, V.; Bassalat, A.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, K.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belloni, A.; Beloborodova, O. L.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Garcia, J. A. Benitez; Benjamin, D. P.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernard, C.; Bernat, P.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Bessidskaia, O.; Besson, N.; Betancourt, C.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boek, T. T.; Bogaerts, J. A.; Bogdanchikov, A. G.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borri, M.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutouil, S.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Brendlinger, K.; Brennan, A. J.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, G.; Brown, J.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.

2014-06-01

241

KEOPS: Kiloparsec Explorer for Optical Planet Search, a direct-imaging optical array at Dome C of Antarctica  

NASA Astrophysics Data System (ADS)

Recent site seeing testing campaigns conducted by our team from University of Nice1 show that Dome C represents the best site on Earth for astronomical high angular resolution (HAR) observations at optical and IR wavelengths. The dramatic gain over relevant HAR parameters r0, L0, ?0 and ?0, added to very low temperatures during the polar winter nights (-70°C), the dry atmosphere and the possibility of continuous observations during several nights make Dome C the ideal site for deploying a kilometric optical interferometer before the 2015 horizon. Here we describe the concept of Kiloparsec Explorer for Optical Planet Search (KEOPS) that is studied by our group at LUAN. KEOPS is an interferometric array of 36 off-axis telescopes, each 1.5m in diameter. Its kilometric baselines open sub-mas snap-shot imaging possibilities to detect and characterize extra-solar planetary systems, especially exo-Earths out to 300 parsecs from the visible to the thermal IR. KEOPS can be considered as a DARWIN/TPF challenger but at a much lower cost.

Vakili, Farrokh; Belu, Adrian; Aristidi, Eric; Fossat, Eric; Maillard, A.; Abe, Lyu; Agabi, Karim; Vernin, Jean; Baptiste Daban, Jean; Hertmanni, Wilfried; Schmider, Francois-Xavier; Assus, Pierre; Coudé du Foresto, Vincent; Swain, Mark R.

2004-10-01

242

Hemispheric asymmetries in visual search  

Microsoft Academic Search

We conducted two visual search experiments, and found that target-detection accuracy and speed were better when the target was projected to the right hemisphere in the feature search condition and better when the target was projected to the left hemisphere in the feature-conjunction search condition. We propose that the highly efficient, so-called parallel search performance characteristic of feature search is

William Poynter; Candice Roberts

2011-01-01

243

Automatic Multilevel Parallelization Using OpenMP  

NASA Technical Reports Server (NTRS)

In this paper we describe the extension of the CAPO parallelization support tool to support multilevel parallelism based on OpenMP directives. CAPO generates OpenMP directives with extensions supported by the NanosCompiler to allow for directive nesting and definition of thread groups. We report first results for several benchmark codes and one full application that have been parallelized using our system.

Jin, Hao-Qiang; Jost, Gabriele; Yan, Jerry; Ayguade, Eduard; Gonzalez, Marc; Martorell, Xavier; Biegel, Bryan (Technical Monitor)

2002-01-01

244

Massively parallel vector processing computer  

SciTech Connect

This patent describes a vector processing node for a computer of the type having a network of simultaneously operating vector processing nodes interconnected by bidirectional external busses for conveying parallel data words between the vector processing nodes. The vector processing node comprising: a bi-directional first bus for conveying parallel data words; a bi-directional second bus for conveying parallel data words; vector memory means connected for read and write access through the second bus for storing vectors comprising sequences of parallel data words conveyed on the second bus; vector processing means connected to the second bus for transmitting parallel data words to and receiving parallel data words from the vector memory means for generating output vectors comprising functions of input vectors stored in the vector memory means and for storing the output vectors in the vector memory means; and control means including a computer processor connected to the first bus, external port means controlled by the computer processor and connected between the first bus and the external busses, and local port means controlled by the computer processor connected between the first and second busses, for transmitting parallel data words to and receiving parallel data words from the first bus, the second bus, the external busses, and the vector memory.

Call, D.B.; Mudrow, A.; Johnson, R.C.; Bennion, R.F.

1990-01-02

245

High Performance Parallel Computing.  

National Technical Information Service (NTIS)

The three major research areas have been parallel structuring of computations, basic software for support of parallel computations and parallel architectures and supporting hardware. The work on parallel structuring of computations falls into three catego...

J. C. Browne

1982-01-01

246

Parallel Computing Explained  

NSDL National Science Digital Library

Several tutorials on parallel computing. Overview of parallel computing. Porting and code parallelization. Scalar, cache, and parallel code tuning. Timing, profiling and performance analysis. Overview of IBM Regatta P690.

Ncsa

247

A direct interaction between a DNA-tracking protein and a promoter recognition protein: implications for searching DNA sequence.  

PubMed Central

Bacteriophage T4 gene 45 protein, gp45, serves as the sliding clamp of viral DNA replication and as the activator of T4 late gene transcription. In the latter context, DNA tracking is an essential feature of the unique mechanism of action. T4 late promoters, which consist of a simple TATA box, TATAAATA, are recognized by the small sigma-family gene 55 protein, gp55, which binds to Escherichia coli RNA polymerase core. A direct and RNA polymerase-independent interaction of gp45 with gp55 has been demonstrated in two ways. (i) gp45 tracks along DNA; co-tracking of gp55 requires the previously documented DNA-loading process of gp45, and can be detected by photochemical crosslinking. (ii) The dynamics of DNA tracking by gp45 can be followed by footprinting; the catenated DNA-tracking state of gp45 is short-lived, but is stabilized by gp55. The ability of this topologically linked DNA-tracking transcriptional activator to interact directly with a promoter recognition protein suggests the existence of multiple pathways of promoter location, which are discussed. Images

Tinker-Kulberg, R L; Fu, T J; Geiduschek, E P; Kassavetis, G A

1996-01-01

248

Search for direct photon production in 200 A GeV S + Au reactions: A status report  

NASA Astrophysics Data System (ADS)

Direct thermal photons in the pT range of 0-5 GeV/c are expected to provide a sensitive probe of the hot dense matter formed in the early stage of relativistic heavy ion collisions. The production of single photons in 200 A GeV S + Au reactions has been investigated using the 3800 element Pbglass calorimeter of CERN experiment WA80. Neutral ?0 and ? cross sections have been measured via their two-photon decay branch yields. In a first analysis of the WA80 results, a slight excess photon yield above that which may be accounted for by hadronic decays was observed for central collisions. A report on the status of the reanalysis of this data is presented.

Awes, Terry C.; Albrecht, R.; Awes, T. C.; Barlag, C.; Berger, F.; Bloomer, M.; Blume, C.; Bock, D.; Bock, R.; Bohne, E.; Bucher, D.; Claesson, G.; Claussen, A.; Clewing, G.; Debbe, R.; Dragon, L.; Eklund, A.; Fokin, S.; Garpman, S.; Glasow, R.; Gustafsson, H. A.; Gutbrod, H. H.; Hansen, O.; Hölker, G.; Idh, J.; Ippolitov, M.; Jacobs, P.; Kampert, K. H.; Karadjev, K.; Kolb, B. W.; Lebedev, A.; Löhner, H.; Lund, I.; Manko, V.; Moskowitz, B.; Obenshain, F. E.; Oskarsson, A.; Otterlund, I.; Peitzmann, T.; Plasil, F.; Poskanzer, A. M.; Purschke, M.; Roters, B.; Saini, S.; Santo, R.; Schmidt, H. R.; Soderstrom, K.; Sorensen, S. P.; Stankus, P. W.; Steffens, K.; Steinhaeuser, P.; Stenlund, E.; Stüken, D.; Vinogradov, A.; Wegner, H.; Young, G. R.; Wa80 Collaboration

1995-02-01

249

Research on parallel algorithm for sequential pattern mining  

NASA Astrophysics Data System (ADS)

Sequential pattern mining is the mining of frequent sequences related to time or other orders from the sequence database. Its initial motivation is to discover the laws of customer purchasing in a time section by finding the frequent sequences. In recent years, sequential pattern mining has become an important direction of data mining, and its application field has not been confined to the business database and has extended to new data sources such as Web and advanced science fields such as DNA analysis. The data of sequential pattern mining has characteristics as follows: mass data amount and distributed storage. Most existing sequential pattern mining algorithms haven't considered the above-mentioned characteristics synthetically. According to the traits mentioned above and combining the parallel theory, this paper puts forward a new distributed parallel algorithm SPP(Sequential Pattern Parallel). The algorithm abides by the principal of pattern reduction and utilizes the divide-and-conquer strategy for parallelization. The first parallel task is to construct frequent item sets applying frequent concept and search space partition theory and the second task is to structure frequent sequences using the depth-first search method at each processor. The algorithm only needs to access the database twice and doesn't generate the candidated sequences, which abates the access time and improves the mining efficiency. Based on the random data generation procedure and different information structure designed, this paper simulated the SPP algorithm in a concrete parallel environment and implemented the AprioriAll algorithm. The experiments demonstrate that compared with AprioriAll, the SPP algorithm had excellent speedup factor and efficiency.

Zhou, Lijuan; Qin, Bai; Wang, Yu; Hao, Zhongxiao

2008-03-01

250

Implementing a parallel C++ runtime system for scalable parallel systems  

Microsoft Academic Search

pC++ is a language extension to C++ designed toallow programmers to compose "concurrent aggregate"collection classes which can be aligned and distributedover the memory hierarchy of a parallel machine ina manner modeled on the High Performance FortranForum (HPFF) directives for Fortran 90. pC++ allowsthe user to write portable and efficient code whichwill run on a wide range of scalable parallel computersystems.

A. Malony; B. Mohr; P. Beckman; D. Gannon; S. Yang; F. Bodin; S. Kesavan

1993-01-01

251

Multi-Target-Directed Ligands and other Therapeutic Strategies in the Search of a Real Solution for Alzheimer's Disease  

PubMed Central

The lack of an adequate therapy for Alzheimer's Disease (AD) contributes greatly to the continuous growing amount of papers and reviews, reflecting the important efforts made by scientists in this field. It is well known that AD is the most common cause of dementia, and up-to-date there is no prevention therapy and no cure for the disease, which contrasts with the enormous efforts put on the task. On the other hand many aspects of AD are currently debated or even unknown. This review offers a view of the current state of knowledge about AD which includes more relevant findings and processes that take part in the disease; it also shows more relevant past, present and future research on therapeutic drugs taking into account the new paradigm “Multi-Target-Directed Ligands” (MTDLs). In our opinion, this paradigm will lead from now on the research toward the discovery of better therapeutic solutions, not only in the case of AD but also in other complex diseases. This review highlights the strategies followed by now, and focuses other emerging targets that should be taken into account for the future development of new MTDLs. Thus, the path followed in this review goes from the pathology and the processes involved in AD to the strategies to consider in on-going and future researches.

Agis-Torres, Angel; Solhuber, Monica; Fernandez, Maria; Sanchez-Montero, J.M.

2014-01-01

252

B physics: measurement of partial widths and search for direct cp violation in d0 meson decays  

SciTech Connect

We present a measurement of relative partial widths and decay rate CP asymmetries in K{sup -}K{sup +} and {pi}{sup -}{pi}{sup +} decays of D{sup 0} mesons produced in p{bar p} collisions at {radical}s = 1.96TeV. We use a sample of 2 x 10{sup 5} D*{sup +} {yields} D{sup 0}{pi}{sup +} (and charge conjugate) decays with the D{sup 0} decaying to K{sup -}{pi}{sup +}, K{sup -}K{sup +}, and {pi}{sup -}{pi}{sup +}, corresponding to 123 pb{sup -1} of data collected by the Collider Detector at Fermilab II experiment at the Fermilab Tevatron collider. No significant direct CP violation is observed. We measure {Lambda}(D{sup 0} {yields} K{sup -}K{sup +})/{Lambda}(D{sup 0} {yields} K{sup -}{pi}{sup +}) = 0.0992 {+-} 0.0011 {+-} 0.0012, {Lambda}(D{sup 0} {yields} {pi}{sup -}{pi}{sup +})/{Lambda}(D{sup 0} {yields} K{sup -}{pi}{sup +}) = 0.03594 {+-} 0.00054 {+-} 0.00040, A{sub CP} (K{sup -}K{sup +}) = (2.0 {+-} 1.2 {+-} 0.6)%, and A{sub CP} ({pi}{sup -}{pi}{sup +}) = (1.0 {+-} 1.3 {+-} 0.6) %, where, in all cases, the first uncertainty is statistical and the second is systematic.

Acosta, D.; The CDF Collaboration

2005-04-04

253

Parallel multi-computers and artificial intelligence  

SciTech Connect

This book examines the present state and future direction of multicomputer parallel architectures for artificial intelligence research and development of artificial intelligence applications. The book provides a survey of the large variety of parallel architectures, describing the current state of the art and suggesting promising architectures to produce artificial intelligence systems such as intelligence systems such as intelligent robots. This book integrates artificial intelligence and parallel processing research areas and discusses parallel processing from the viewpoint of artificial intelligence.

Uhr, L.

1986-01-01

254

3D finite-difference frequency-domain modeling of visco-acoustic wave propagation using a massively parallel direct solver: A feasibility study  

Microsoft Academic Search

We present a finite-difference frequency-domain method for 3D visco-acoustic wave propagation modeling. In the frequency domain, the underlying numerical problem is the resolution of a large sparse system of linear equations whose right-hand side termisthesource.Thissystemissolvedwithamassivelyparallel direct solver. We first present an optimal 3D finite-difference stencil for frequency-domain modeling. The method is based on a parsimonious staggered-grid method. Differential operators are

Stéphane Operto; Jean Virieux; Patrick Amestoy; Jean-Yves L'Excellent; Luc Giraud; Hafedh Ben Hadj Ali

2007-01-01

255

Calculation of geometric phases in electric dipole searches with trapped spin-1/2 particles based on direct solution of the Schrödinger equation  

NASA Astrophysics Data System (ADS)

Pendlebury etal . [Phys. Rev. A 70, 032102 (2004), 10.1103/PhysRevA.70.032102] were the first to investigate the role of geometric phases in searches for an electric dipole moment (EDM) of elementary particles based on Ramsey-separated oscillatory field magnetic resonance with trapped ultracold neutrons and comagnetometer atoms. Their work was based on the Bloch equation and later work using the density matrix corroborated the results and extended the scope to describe the dynamics of spins in general fields and in bounded geometries. We solve the Schrödinger equation directly for cylindrical trap geometry and obtain a full description of EDM-relevant spin behavior in general fields, including the short-time transients and vertical spin oscillation in the entire range of particle velocities. We apply this method to general macroscopic fields and to the field of a microscopic magnetic dipole.

Steyerl, A.; Kaufman, C.; Müller, G.; Malik, S. S.; Desai, A. M.; Golub, R.

2014-05-01

256

Codex search patterns  

US Patent & Trademark Office Database

A search engine optimizer that works independently and in parallel with a browser and search engine supercomputer to gather, analyze, and distill input information interactively. The optimizer reorganizes the input, and providing an optimized version as an output. The optimized version of the input (e.g. output) is sent to the search engine that responds to the end user with search results. The optimizer recognizes each request as a pattern and stores the pattern in an advanced Glyph format. This permits the optimizer to identify a left and ride side checkmate combination required to achieve certitude.

2013-02-26

257

Minimizing the makespan for Unrelated Parallel Machines  

Microsoft Academic Search

In this paper, we study the unrelated parallel machine problem for minimizing the makespan, which is NP-hard. We used Simulated Annealing (SA) and Tabu Search (TS) with Neighborhood Search (NS) based on the structure of the problem. We also used a modied SA algorithm, which gives better results than the traditional SA and developed an eectiv e heuristic for the

Yunsong Guo; Andrew Lim; Brian Rodrigues; Liang Yang

2007-01-01

258

Parallel execution model for Prolog  

SciTech Connect

One candidate language for parallel symbolic computing is Prolog. Numerous ways for executing Prolog in parallel have been proposed, but current efforts suffer from several deficiencies. Many cannot support fundamental types of concurrency in Prolog. Other models are of purely theoretical interest, ignoring implementation costs. Detailed simulation studies of execution models are scare; at present little is known about the costs and benefits of executing Prolog in parallel. In this thesis, a new parallel execution model for Prolog is presented: the PPP model or Parallel Prolog Processor. The PPP supports AND-parallelism, OR-parallelism, and intelligent backtracking. An implementation of the PPP is described, through the extension of an existing Prolog abstract machine architecture. Several examples of PPP execution are presented, and compilation to the PPP abstract instruction set is discussed. The performance effects of this model are reported, based on a simulation of a large benchmark set. The implications of these results for parallel Prolog systems are discussed, and directions for future work are indicated.

Fagin, B.S.

1987-01-01

259

Parallel pivoting combined with parallel reduction  

NASA Technical Reports Server (NTRS)

Parallel algorithms for triangularization of large, sparse, and unsymmetric matrices are presented. The method combines the parallel reduction with a new parallel pivoting technique, control over generations of fill-ins and a check for numerical stability, all done in parallel with the work being distributed over the active processes. The parallel technique uses the compatibility relation between pivots to identify parallel pivot candidates and uses the Markowitz number of pivots to minimize fill-in. This technique is not a preordering of the sparse matrix and is applied dynamically as the decomposition proceeds.

Alaghband, Gita

1987-01-01

260

Computer-Aided Parallelizer and Optimizer  

NASA Technical Reports Server (NTRS)

The Computer-Aided Parallelizer and Optimizer (CAPO) automates the insertion of compiler directives (see figure) to facilitate parallel processing on Shared Memory Parallel (SMP) machines. While CAPO currently is integrated seamlessly into CAPTools (developed at the University of Greenwich, now marketed as ParaWise), CAPO was independently developed at Ames Research Center as one of the components for the Legacy Code Modernization (LCM) project. The current version takes serial FORTRAN programs, performs interprocedural data dependence analysis, and generates OpenMP directives. Due to the widely supported OpenMP standard, the generated OpenMP codes have the potential to run on a wide range of SMP machines. CAPO relies on accurate interprocedural data dependence information currently provided by CAPTools. Compiler directives are generated through identification of parallel loops in the outermost level, construction of parallel regions around parallel loops and optimization of parallel regions, and insertion of directives with automatic identification of private, reduction, induction, and shared variables. Attempts also have been made to identify potential pipeline parallelism (implemented with point-to-point synchronization). Although directives are generated automatically, user interaction with the tool is still important for producing good parallel codes. A comprehensive graphical user interface is included for users to interact with the parallelization process.

Jin, Haoqiang

2011-01-01

261

Parallelized laser-direct patterning of nanocrystalline metal thin films by use of a pulsed laser-induced thermo-elastic force.  

PubMed

Thin film patterning by the conventional lithographic technique requires a number of steps including the deposition, development, and removal of the photoresist layer. Here we demonstrate that metal thin films evaporated on glass can be directly patterned by a spatially modulated pulsed Nd-YAG laser beam (wavelength = 1064 nm, pulse width = 6 ns) incident from the backside of the substrate. This method utilizes a pulsed laser-induced thermo-elastic force exerted on the film which plays a role in detaching it from the substrate. High-fidelity patterns at the micrometer scale have been fabricated over a few square centimeters by a single pulse with pulse energy of 850 mJ. This is attributed to the fact that deposited metal films are polycrystalline with nano-sized grains, and thus localized etching of the material is possible with shearing along the weakly bonded grain boundary regions. We have also developed a nano-block model to simulate the laser-direct patterning of nanocrystalline thin films. Experimental results could be well described with this simulation model. The patterning process presented here provides a simple photoresist-free route to fabricate metal thin film patterns on transparent substrates. PMID:19468166

Yoo, Hyeonggeun; Shin, Hyunkwon; Sim, Boyeon; Kim, Sangtae; Lee, Myeongkyu

2009-06-17

262

Toward Parallel Document Clustering  

SciTech Connect

A key challenge to automated clustering of documents in large text corpora is the high cost of comparing documents in a multimillion dimensional document space. The Anchors Hierarchy is a fast data structure and algorithm for localizing data based on a triangle inequality obeying distance metric, the algorithm strives to minimize the number of distance calculations needed to cluster the documents into “anchors” around reference documents called “pivots”. We extend the original algorithm to increase the amount of available parallelism and consider two implementations: a complex data structure which affords efficient searching, and a simple data structure which requires repeated sorting. The sorting implementation is integrated with a text corpora “Bag of Words” program and initial performance results of end-to-end a document processing workflow are reported.

Mogill, Jace A.; Haglin, David J.

2011-09-01

263

Parallel Programming with Polaris  

Microsoft Academic Search

Parallel programming tools are limited, making effective parallel programming difficult and cumbersome. Compilers that translate conventional sequential programs into parallel form would liberate programmers from the complexities of explicit, machine oriented parallel programming. The paper discusses parallel programming with Polaris, an experimental translator of conventional Fortran programs that target machines such as the Cray T3D

William Blume; Ramon Doallo; Rudolf Eigenmann; John Grout; Jay Hoeflinger; Thomas Lawrence; Jaejin Lee; David A. Padua; Yunheung Paek; William M. Pottenger; Lawrence Rauchwerger; Peng Tu

1996-01-01

264

A search for arrival direction clustering in the HiRes-I monocular data above 1019.5 eV  

NASA Astrophysics Data System (ADS)

In the past few years, small scale anisotropy has become a primary focus in the search for source of ultra-high energy cosmic rays (UHECRs). The Akeno Giant Air Shower Array (AGASA) has reported the presence of clusters of event arrival directions in their highest energy data set. The High Resolution Fly’s Eye (HiRes) has accumulated an exposure in one of its monocular eyes at energies above 1019.5 eV comparable to that of AGASA. However, monocular events observed with an air fluorescence detector are characterized by highly asymmetric angular resolution. A method is developed for measuring autocorrelation with asymmetric angular resolution. It is concluded that HiRes-I observations are consistent with no autocorrelation and that the sensitivity to clustering of the HiRes-I detector is comparable to that of the reported AGASA data set. Furthermore, we state with a 90% confidence level that not more than 13% of the observed HiRes-I events above 1019.5 eV could be sharing common arrival directions. However, because a measure of autocorrelation makes no assumption of the underlying astrophysical mechanism that results in clustering phenomena, we cannot claim that the HiRes monocular analysis and the AGASA analysis are inconsistent beyond a specified confidence level.

High Resolution Fly'S Eye Collaboration; Abbasi, R. U.; Abu-Zayyad, T.; Amann, J. F.; Archbold, G.; Atkins, R.; Bellido, J. A.; Belov, K.; Belz, J. W.; Benzvi, S.; Bergman, D. R.; Burt, G. W.; Cao, Z.; Clay, R. W.; Connolly, B.; Dawson, B. R.; Deng, W.; Fedorova, Y.; Findlay, J.; Finley, C. B.; Hanlon, W. F.; Hoffman, C. M.; Holzscheiter, M. H.; Hughes, G. A.; Hüntemeyer, P.; Jui, C. C. H.; Kim, K.; Kirn, M. A.; Loh, E. C.; Maestas, M. M.; Manago, N.; Marek, L. J.; Martens, K.; Matthews, J. A. J.; Matthews, J. N.; O'Neill, A.; Painter, C. A.; Perera, L.; Reil, K.; Riehle, R.; Roberts, M.; Sasaki, M.; Schnetzer, S. R.; Simpson, K. M.; Sinnis, G.; Smith, J. D.; Snow, R.; Sokolsky, P.; Song, C.; Springer, R. W.; Stokes, B. T.; Thomas, J. R.; Thomas, S. B.; Thomson, G. B.; Tupa, D.; Westerhoff, S.; Wiencke, L. R.; Zech, A.

2004-11-01

265

Template based parallel checkpointing in a massively parallel computer system  

DOEpatents

A method and apparatus for a template based parallel checkpoint save for a massively parallel super computer system using a parallel variation of the rsync protocol, and network broadcast. In preferred embodiments, the checkpoint data for each node is compared to a template checkpoint file that resides in the storage and that was previously produced. Embodiments herein greatly decrease the amount of data that must be transmitted and stored for faster checkpointing and increased efficiency of the computer system. Embodiments are directed to a parallel computer system with nodes arranged in a cluster with a high speed interconnect that can perform broadcast communication. The checkpoint contains a set of actual small data blocks with their corresponding checksums from all nodes in the system. The data blocks may be compressed using conventional non-lossy data compression algorithms to further reduce the overall checkpoint size.

Archer, Charles Jens (Rochester, MN); Inglett, Todd Alan (Rochester, MN)

2009-01-13

266

A Priori Analysis of Subgrid Mass Flux Vectors from Massively Parallel Direct Numerical Simulations of High Pressure H2/O2 Reacting Shear Layers  

NASA Astrophysics Data System (ADS)

Direct Numerical Simulations (DNS) are conducted for temporally developing reacting H2/O2 shear layers at an ambient pressure of 100atm. The compressible form of the governing equations are coupled with the Peng Robinson real gas equation of state and are solved using eighth order central finite differences and fourth order Runge Kutta time integration with resolutions up to ˜3/4 billion grid points. The formulation includes a detailed pressure dependent kinetics mechanism having 8 species and 19 steps, detailed property models, and generalized forms of the multicomponent heat and mass diffusion vectors derived from nonequilibrium thermodynamics and fluctuation theory. The DNS is performed over a range of Reynolds numbers up to 4500 based on the free stream velocity difference and initial vorticity thickness. The results are then analyzed in an a priori manner to illustrate the role of the subgrid mass flux vector within the filtered form of the governing equations relevant to Large Eddy Simulations. The subgrid mass flux vector is found to be a significant term; particularly within localized regions of the flame.

Foster, Justin; Miller, Richard

2011-11-01

267

Special parallel processing workshop  

SciTech Connect

This report contains viewgraphs from the Special Parallel Processing Workshop. These viewgraphs deal with topics such as parallel processing performance, message passing, queue structure, and other basic concept detailing with parallel processing.

NONE

1994-12-01

268

Parallel Mesh Generation  

Microsoft Academic Search

Parallel mesh generation is a relatively new research area between the boundaries of two scientific computing disciplines:\\u000a computational geometry and parallel computing. In this chapter we present a survey of parallel unstructured mesh generation\\u000a methods. Parallel mesh generation methods decompose the original mesh generation problem into smaller sub-problems which are\\u000a meshed in parallel. We organize the parallel mesh generation methods

Nikos Chrisochoides

269

A parallel execution model for Prolog  

SciTech Connect

In this thesis a new parallel execution model for Prolog is presented: The PPP model or Parallel Prolog Processor. The PPP supports AND-parallelism, OR- parallelism, and intelligent backtracking. An implementation of the PPP is described, through the extension of an existing Prolog abstract machine architecture. Several examples of PPP execution are presented and compilation to the PPP abstract instructions set is discussed. The performance effects of this model are reported, based on a simulation of a large benchmark set. The implications of these results for parallel Prolog systems are discussed, and directions for future work are indicated.

Fagin, B.

1987-01-01

270

Using volume holograms to search digital databases  

Microsoft Academic Search

Holographic data storage ofiers the potential for simultaneous search of an entire database by performing multiple optical correlations between stored data pages and a search argument (1, 2). This content{addressable retrieval produces one analog correlation score for each stored volume hologram. We have previously developed fuzzy encoding techniques for this fast parallel search, and holographically searched a small database with

Geofirey W. Burr; George Maltezos; Felix Grawert; Sebastian Kobras; Holger Hanssen; Hans Coufal

2001-01-01

271

Software behavior oriented parallelization  

Microsoft Academic Search

Many sequential applications are difficult to parallelize because of unpredictable control flow, indirect data access, and input- dependent parallelism. These difficulties led us to build a software system for behavior oriented parallelization (BOP), which allows a program to be parallelized based on partial information about pro- gram behavior, for example, a user reading just part of the source code, or

Chen Ding; Xipeng Shen; Kirk Kelsey; Chris Tice; Ruke Huang; Chengliang Zhang

2007-01-01

272

Parallel Mandelbrot Set Model  

NSDL National Science Digital Library

The Parallel Mandelbrot Set Model is a parallelization of the sequential MandelbrotSet model, which does all the computations on a single processor core. This parallelization is able to use a computer with more than one cores (or processors) to carry out the same computation, thus speeding up the process. The parallelization is done using the model elements in the Parallel Java group. These model elements allow easy use of the Parallel Java library created by Alan Kaminsky. In particular, the parallelization used for this model is based on code in Chapters 11 and 12 of Kaminsky's book Building Parallel Java. The Parallel Mandelbrot Set Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double click the ejs_chaos_ParallelMandelbrotSet.jar file to run the program if Java is installed.

Franciscouembre

2011-11-24

273

Ejs Parallel Plate Capacitor Model  

NSDL National Science Digital Library

The Ejs Parallel Plate Capacitor model displays a parallel-plate capacitor which consists of two identical metal plates, placed parallel to one another. The capacitor can be charged by connecting one plate to the positive terminal of a battery and the other plate to the negative terminal. The dielectric constant and the separation of the plates can be changed via sliders. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. Ejs Parallel Plate Capacitor model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_capacitor.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for Newtonian mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Duffy, Andrew

2008-07-14

274

Hierarchically tiled arrays for parallelism and locality  

Microsoft Academic Search

Parallel programming is facilitated by constructs which, unlike the widely used SPMD paradigm, provide programmers with a global view of the code and data structures. These constructs could be compiler directives containing information about data and task distribution, language extensions specifically designed for paral- lel computation, or classes that encapsulate parallelism. In this paper, we describe a class developed at

Jia Guo; Ganesh Bikshandi; Daniel Hoeflinger; Gheorghe Almási; Basilio B. Fraguela; María Jesús Garzarán; David A. Padua; Christoph Von Praun

2006-01-01

275

Accelerated Waveform Methods for Parallel Transient Simulation  

Microsoft Academic Search

In this paper we compare accelerated waveform relaxation algorithms to pointwise direct and iterative methods for the parallel transient simulation of semiconductor device s on parallel machines. Experimental results are presented for simulations on single (serial) workstations, clusters of workstations, and an IBM SP-2. The results show that ac- celerated waveform methods are competitive with standard pointwise methods on serial

Andrew Lumsdaine; Mark W. Reichelt; Jeffrey M. Squyres; Jacob K. White

276

Integrated Task and Data Parallel Programming  

NASA Technical Reports Server (NTRS)

This research investigates the combination of task and data parallel language constructs within a single programming language. There are an number of applications that exhibit properties which would be well served by such an integrated language. Examples include global climate models, aircraft design problems, and multidisciplinary design optimization problems. Our approach incorporates data parallel language constructs into an existing, object oriented, task parallel language. The language will support creation and manipulation of parallel classes and objects of both types (task parallel and data parallel). Ultimately, the language will allow data parallel and task parallel classes to be used either as building blocks or managers of parallel objects of either type, thus allowing the development of single and multi-paradigm parallel applications. 1995 Research Accomplishments In February I presented a paper at Frontiers 1995 describing the design of the data parallel language subset. During the spring I wrote and defended my dissertation proposal. Since that time I have developed a runtime model for the language subset. I have begun implementing the model and hand-coding simple examples which demonstrate the language subset. I have identified an astrophysical fluid flow application which will validate the data parallel language subset. 1996 Research Agenda Milestones for the coming year include implementing a significant portion of the data parallel language subset over the Legion system. Using simple hand-coded methods, I plan to demonstrate (1) concurrent task and data parallel objects and (2) task parallel objects managing both task and data parallel objects. My next steps will focus on constructing a compiler and implementing the fluid flow application with the language. Concurrently, I will conduct a search for a real-world application exhibiting both task and data parallelism within the same program. Additional 1995 Activities During the fall I collaborated with Andrew Grimshaw and Adam Ferrari to write a book chapter which will be included in Parallel Processing in C++ edited by Gregory Wilson. I also finished two courses, Compilers and Advanced Compilers, in 1995. These courses complete my class requirements at the University of Virginia. I have only my dissertation research and defense to complete.

Grimshaw, A. S.

1998-01-01

277

Parallel-Access Alinement Network Using Barrel Switches  

NASA Technical Reports Server (NTRS)

Practical version of parallel-access alinement network utilizes two barrel switches for interfacing N parallel memory modules with N parallel processing elements. Switches are interconnected where 17 memory ports (MP's) are connected to 17 processor ports (PP's). Network uses two electronic barrel switches to direct data flow in parallel data-processing system. Each switch can shift a multibit parallel input a predetermined number of places to left or right, end off, or end around in one clock-pulse.

Barnes, George H.

1982-01-01

278

Fast data parallel polygon rendering  

SciTech Connect

This paper describes a parallel method for polygonal rendering on a massively parallel SIMD machine. This method, based on a simple shading model, is targeted for applications which require very fast polygon rendering for extremely large sets of polygons such as is found in many scientific visualization applications. The algorithms described in this paper are incorporated into a library of 3D graphics routines written for the Connection Machine. The routines are implemented on both the CM-200 and the CM-5. This library enables a scientists to display 3D shaded polygons directly from a parallel machine without the need to transmit huge amounts of data to a post-processing rendering system.

Ortega, F.A.; Hansen, C.D.

1993-09-01

279

DC Circuits: Parallel Resistances  

NSDL National Science Digital Library

In this interactive learning activity, students will learn about parallel circuits. They will measure and calculate the resistance of parallel circuits and answer several questions about the example circuit shown.

2013-07-30

280

Parallel Particle Swarm Optimizer.  

National Technical Information Service (NTIS)

Time requirements for the solving of complex large-scale engineering problems can be substantially reduced by using parallel computation. Motivated by a computationally demanding biomechanical system identification problem, we introduce a parallel impleme...

J. F. Schutte B. Fregly R. T. Haftka A. D. George

2003-01-01

281

Parallel flow diffusion battery  

DOEpatents

A parallel flow diffusion battery for determining the mass distribution of an aerosol has a plurality of diffusion cells mounted in parallel to an aerosol stream, each diffusion cell including a stack of mesh wire screens of different density.

Yeh, H.C.; Cheng, Y.S.

1984-01-01

282

Two portable parallel tridiagonal solvers  

SciTech Connect

Many scientific computer codes involve linear systems of equations which are coupled only between nearest neighbors in a single dimension. The most common situation can be formulated as a tridiagonal matrix relating source terms and unknowns. This system of equations is commonly solved using simple forward and back substitution. The usual algorithm is spectacularly ill suited for parallel processing with distributed data, since information must be sequentially communicated across all domains. Two new tridiagonal algorithms have been implemented in FORTRAN 77. The two algorithms differ only in the form of the unknown which is to be found. The first and simplest algorithm solves for a scalar quantity evaluated at each point along the single dimension being considered. The second algorithm solves for a vector quantity evaluated at each point. The solution method is related to other recently published approaches, such as that of Bondeli. An alternative parallel tridiagonal solver, used as part of an Alternating Direction Implicit (ADI) scheme, has recently been developed at LLNL by Lambert. For a discussion of useful parallel tridiagonal solvers, see the work of Mattor, et al. Previous work appears to be concerned only with scalar unknowns. This paper presents a new technique which treats both scalar and vector unknowns. There is no restriction upon the sizes of the subdomains. Even though the usual tridiagonal formulation may not be theoretically optimal when used iteratively, it is used in so many computer codes that it appears reasonable to write a direct substitute for it. The new tridiagonal code can be used on parallel machines with a minimum of disruption to pre-existing programming. As tested on various parallel computers, the parallel code shows efficiency greater than 50% (that is, more than half of the available computer operations are used to advance the calculation) when each processor is given at least 100 unknowns for which to solve.

Eltgroth, P.G.

1994-07-15

283

Parallel Implicit Algorithms for CFD  

NASA Technical Reports Server (NTRS)

The main goal of this project was efficient distributed parallel and workstation cluster implementations of Newton-Krylov-Schwarz (NKS) solvers for implicit Computational Fluid Dynamics (CFD.) "Newton" refers to a quadratically convergent nonlinear iteration using gradient information based on the true residual, "Krylov" to an inner linear iteration that accesses the Jacobian matrix only through highly parallelizable sparse matrix-vector products, and "Schwarz" to a domain decomposition form of preconditioning the inner Krylov iterations with primarily neighbor-only exchange of data between the processors. Prior experience has established that Newton-Krylov methods are competitive solvers in the CFD context and that Krylov-Schwarz methods port well to distributed memory computers. The combination of the techniques into Newton-Krylov-Schwarz was implemented on 2D and 3D unstructured Euler codes on the parallel testbeds that used to be at LaRC and on several other parallel computers operated by other agencies or made available by the vendors. Early implementations were made directly in Massively Parallel Integration (MPI) with parallel solvers we adapted from legacy NASA codes and enhanced for full NKS functionality. Later implementations were made in the framework of the PETSC library from Argonne National Laboratory, which now includes pseudo-transient continuation Newton-Krylov-Schwarz solver capability (as a result of demands we made upon PETSC during our early porting experiences). A secondary project pursued with funding from this contract was parallel implicit solvers in acoustics, specifically in the Helmholtz formulation. A 2D acoustic inverse problem has been solved in parallel within the PETSC framework.

Keyes, David E.

1998-01-01

284

Computing contingency statistics in parallel.  

SciTech Connect

Statistical analysis is typically used to reduce the dimensionality of and infer meaning from data. A key challenge of any statistical analysis package aimed at large-scale, distributed data is to address the orthogonal issues of parallel scalability and numerical stability. Many statistical techniques, e.g., descriptive statistics or principal component analysis, are based on moments and co-moments and, using robust online update formulas, can be computed in an embarrassingly parallel manner, amenable to a map-reduce style implementation. In this paper we focus on contingency tables, through which numerous derived statistics such as joint and marginal probability, point-wise mutual information, information entropy, and {chi}{sup 2} independence statistics can be directly obtained. However, contingency tables can become large as data size increases, requiring a correspondingly large amount of communication between processors. This potential increase in communication prevents optimal parallel speedup and is the main difference with moment-based statistics where the amount of inter-processor communication is independent of data size. Here we present the design trade-offs which we made to implement the computation of contingency tables in parallel.We also study the parallel speedup and scalability properties of our open source implementation. In particular, we observe optimal speed-up and scalability when the contingency statistics are used in their appropriate context, namely, when the data input is not quasi-diffuse.

Bennett, Janine Camille; Thompson, David; Pebay, Philippe Pierre

2010-09-01

285

Parallelizing Timed Petri Net simulations  

NASA Technical Reports Server (NTRS)

The possibility of using parallel processing to accelerate the simulation of Timed Petri Nets (TPN's) was studied. It was recognized that complex system development tools often transform system descriptions into TPN's or TPN-like models, which are then simulated to obtain information about system behavior. Viewed this way, it was important that the parallelization of TPN's be as automatic as possible, to admit the possibility of the parallelization being embedded in the system design tool. Later years of the grant were devoted to examining the problem of joint performance and reliability analysis, to explore whether both types of analysis could be accomplished within a single framework. In this final report, the results of our studies are summarized. We believe that the problem of parallelizing TPN's automatically for MIMD architectures has been almost completely solved for a large and important class of problems. Our initial investigations into joint performance/reliability analysis are two-fold; it was shown that Monte Carlo simulation, with importance sampling, offers promise of joint analysis in the context of a single tool, and methods for the parallel simulation of general Continuous Time Markov Chains, a model framework within which joint performance/reliability models can be cast, were developed. However, very much more work is needed to determine the scope and generality of these approaches. The results obtained in our two studies, future directions for this type of work, and a list of publications are included.

Nicol, David M.

1993-01-01

286

Verbal and Visual Parallelism  

ERIC Educational Resources Information Center

This study investigates the practice of presenting multiple supporting examples in parallel form. The elements of parallelism and its use in argument were first illustrated by Aristotle. Although real texts may depart from the ideal form for presenting multiple examples, rhetorical theory offers a rationale for minimal, parallel presentation. The…

Fahnestock, Jeanne

2003-01-01

287

CFD on parallel computers  

NASA Astrophysics Data System (ADS)

CFD or Computational Fluid Dynamics is one of the scientific disciplines that has always posed new challenges to the capabilities of the modern, ultra-fast supercomputers, and now to the even faster parallel computers. For applications where number crunching is of primary importance, there is perhaps no escaping parallel computers since sequential computers can only be (as projected) as fast as a few gigaflops and no more, unless, of course, some altogether new technology appears in future. For parallel computers, on the other hand, there is no such limit since any number of processors can be made to work in parallel. Computationally demanding CFD codes and parallel computers are therefore soul-mates, and will remain so for all foreseeable future. So much so that there is a separate and fast-emerging discipline that tackles problems specific to CFD as applied to parallel computers. For some years now, there is an international conference on parallel CFD. So, one can indeed say that parallel CFD has arrived. To understand how CFD codes are parallelized, one must understand a little about how parallel computers function. Therefore, in what follows we will first deal with parallel computers, how a typical CFD code (if there is one such) looks like, and then the strategies of parallelization.

Basu, A. J.

1994-10-01

288

NAS Parallel Benchmarks.  

National Technical Information Service (NTIS)

The NAS Parallel Benchmarks (NPB) are a suite of parallel computer performance benchmarks. They were originally developed at the NASA Ames Research Center in 1991 to assess high-end parallel supercomputers. Although they are no longer used as widely as th...

D. H. Bailey

2009-01-01

289

Improved task scheduling for parallel simulations. Master's thesis  

SciTech Connect

The objective of this investigation is to design, analyze, and validate the generation of optimal schedules for simulation systems. Improved performance in simulation execution times can greatly improve the return rate of information provided by such simulations resulting in reduced development costs of future computer/electronic systems. Optimal schedule generation of precedence-constrained task systems including iterative feedback systems such as VHDL or war gaming simulations for execution on a parallel computer is known to be N P-hard. Efficiently parallelizing such problems takes full advantage of present computer technology to achieve a significant reduction in the search times required. Unfortunately, the extreme combinatoric 'explosion' of possible task assignments to processors creates an exponential search space prohibitive on any computer for search algorithms which maintain more than one branch of the search graph at any one time. This work develops various parallel modified backtracking (MBT) search algorithms for execution on an iPSC/2 hypercube that bound the space requirements and produce an optimally minimum schedule with linear speed-up. The parallel MBT search algorithm is validated using various feedback task simulation systems which are scheduled for execution on an iPSC/2 hypercube. The search time, size of the enumerated search space, and communications overhead required to ensure efficient utilization during the parallel search process are analyzed. The various applications indicated appreciable improvement in performance using this method.

McNear, A.E.

1991-12-01

290

Search Posts  

Cancer.gov

skip navigation NCI Office of Acquisitions Home About OA Contact Us Outreach Welcome Login Register All Posts Search Posts Help Search Posts Announcement Type*: Small Business Outreach Solicitation Award Keywords*: (Type in text or number to search

291

The performance of parallel Prolog programs  

SciTech Connect

This paper presents performance results for a parallel execution model for Prolog that supports AND-parallelism, OR-parallelism, and intelligent backtracking. The results show that restricted AND-parallelism is of limited benefit for small programs, but produced speedups from 7 to 10 on two large programs. Parallelism was generally not found to be useful for the benchmarks examined if the semantics of Prolog were preserved. Of particular interest is the phenomenon of supermultiplicative behavior, in which the performance improvement obtained when more than one technique is employed is greater than the product of the performance improvements due to each technique individually. The implications of the performance results for parallel Prolog systems are discussed, and directions for future work are indicated.

Fagin, B.S. (Dartmouth Coll., Hanover, NH (USA). Thayer School of Engineering); Despain, A.M. (University of Southern California, Los Angeles, CA (USA). Dept. of Electrical Engineering)

1990-12-01

292

Searching for Exoplanets.  

National Technical Information Service (NTIS)

The series of investigations which lead to the conclusion that a serious search for planets orbiting stars other than our Sun (exoplanets) is feasible, are reviewed. The expectation of a search and the means of direct and indirect detection that would be ...

B. F. Burke

1992-01-01

293

Yahoo People Search  

NSDL National Science Digital Library

In 1996 Yahoo added this enhancement to its popular Internet directory service. It's People Search allows you to find telephone numbers and email addresses by entering a search form. The telephone directory is supplied by Database America (the provider of the Switchboard.com database), and the email interface directly queries Four11.com.

1996-01-01

294

Message passing with parallel queue traversal  

DOEpatents

In message passing implementations, associative matching structures are used to permit list entries to be searched in parallel fashion, thereby avoiding the delay of linear list traversal. List management capabilities are provided to support list entry turnover semantics and priority ordering semantics.

Underwood, Keith D. (Albuquerque, NM); Brightwell, Ronald B. (Albuquerque, NM); Hemmert, K. Scott (Albuquerque, NM)

2012-05-01

295

Parallel Imaging Microfluidic Cytometer  

PubMed Central

By adding an additional degree of freedom from multichannel flow, the parallel microfluidic cytometer (PMC) combines some of the best features of flow cytometry (FACS) and microscope-based high-content screening (HCS). The PMC (i) lends itself to fast processing of large numbers of samples, (ii) adds a 1-D imaging capability for intracellular localization assays (HCS), (iii) has a high rare-cell sensitivity and, (iv) has an unusual capability for time-synchronized sampling. An inability to practically handle large sample numbers has restricted applications of conventional flow cytometers and microscopes in combinatorial cell assays, network biology, and drug discovery. The PMC promises to relieve a bottleneck in these previously constrained applications. The PMC may also be a powerful tool for finding rare primary cells in the clinic. The multichannel architecture of current PMC prototypes allows 384 unique samples for a cell-based screen to be read out in approximately 6–10 minutes, about 30-times the speed of most current FACS systems. In 1-D intracellular imaging, the PMC can obtain protein localization using HCS marker strategies at many times the sample throughput of CCD-based microscopes or CCD-based single-channel flow cytometers. The PMC also permits the signal integration time to be varied over a larger range than is practical in conventional flow cytometers. The signal-to-noise advantages are useful, for example, in counting rare positive cells in the most difficult early stages of genome-wide screening. We review the status of parallel microfluidic cytometry and discuss some of the directions the new technology may take.

Ehrlich, Daniel J.; McKenna, Brian K.; Evans, James G.; Belkina, Anna C.; Denis, Gerald V.; Sherr, David; Cheung, Man Ching

2011-01-01

296

Parallel I/O Systems  

NSDL National Science Digital Library

* Redundant disk array architectures,* Fault tolerance issues in parallel I/O systems,* Caching and prefetching,* Parallel file systems,* Parallel I/O systems, * Parallel I/O programming paradigms, * Parallel I/O applications and environments, * Parallel programming with parallel I/O

Apon, Amy

297

Parallel Atomistic Simulations  

SciTech Connect

Algorithms developed to enable the use of atomistic molecular simulation methods with parallel computers are reviewed. Methods appropriate for bonded as well as non-bonded (and charged) interactions are included. While strategies for obtaining parallel molecular simulations have been developed for the full variety of atomistic simulation methods, molecular dynamics and Monte Carlo have received the most attention. Three main types of parallel molecular dynamics simulations have been developed, the replicated data decomposition, the spatial decomposition, and the force decomposition. For Monte Carlo simulations, parallel algorithms have been developed which can be divided into two categories, those which require a modified Markov chain and those which do not. Parallel algorithms developed for other simulation methods such as Gibbs ensemble Monte Carlo, grand canonical molecular dynamics, and Monte Carlo methods for protein structure determination are also reviewed and issues such as how to measure parallel efficiency, especially in the case of parallel Monte Carlo algorithms with modified Markov chains are discussed.

HEFFELFINGER,GRANT S.

2000-01-18

298

Introduction to parallel computing  

SciTech Connect

Today's supercomputers and parallel computers provide an unprecedented amount of computational power in one machine. A basic understanding of the parallel computing techniques that assist in the capture and utilization of that computational power is essential to appreciate the capabilities and the limitations of parallel supercomputers. In addition, an understanding of technical vocabulary is critical in order to converse about parallel computers. The relevant techniques, vocabulary, currently available hardware architectures, and programming languages which provide the basic concepts of parallel computing are introduced in this document. This document updates the document entitled Introduction to Parallel Supercomputing, M88-42, October 1988. It includes a new section on languages for parallel computers, updates the hardware related sections, and includes current references.

Lafferty, E.L.; Michaud, M.C.; Prelle, M.J.; Goethert, J.B.

1992-05-01

299

Real-time trajectory optimization on parallel processors  

NASA Technical Reports Server (NTRS)

A parallel algorithm has been developed for rapidly solving trajectory optimization problems. The goal of the work has been to develop an algorithm that is suitable to do real-time, on-line optimal guidance through repeated solution of a trajectory optimization problem. The algorithm has been developed on an INTEL iPSC/860 message passing parallel processor. It uses a zero-order-hold discretization of a continuous-time problem and solves the resulting nonlinear programming problem using a custom-designed augmented Lagrangian nonlinear programming algorithm. The algorithm achieves parallelism of function, derivative, and search direction calculations through the principle of domain decomposition applied along the time axis. It has been encoded and tested on 3 example problems, the Goddard problem, the acceleration-limited, planar minimum-time to the origin problem, and a National Aerospace Plane minimum-fuel ascent guidance problem. Execution times as fast as 118 sec of wall clock time have been achieved for a 128-stage Goddard problem solved on 32 processors. A 32-stage minimum-time problem has been solved in 151 sec on 32 processors. A 32-stage National Aerospace Plane problem required 2 hours when solved on 32 processors. A speed-up factor of 7.2 has been achieved by using 32-nodes instead of 1-node to solve a 64-stage Goddard problem.

Psiaki, Mark L.

1993-01-01

300

Parallel Particle Swarm Optimization Algorithm Accelerated by Asynchronous Evaluations.  

National Technical Information Service (NTIS)

A parallel Particle Swarm Optimization (PSO) algorithm is presented. Particle swarm optimization is a fairly recent addition to the family of non-gradient based, probabilistic search algorithms that is based on a simplified social model and is closely tie...

G. Venter J. Sobieszczanski-Sobieski

2005-01-01

301

Quantum Search Algorithms  

NASA Astrophysics Data System (ADS)

This article reviews recent progress in quantum database search algorithms. The subject is presented in a self-contained and pedagogical way. The problem of searching a large database (a Hilbert space) for a target item is performed by the famous Grover algorithm which locates the target item with high probability and a quadratic speed-up compared with the corresponding classical algorithm. If the database is partitioned into blocks and one is searching for the block containing the target item instead of the target item itself, then the problem is referred to as partial search. Partial search trades accuracy for speed and the most efficient version is the Grover-Radhakrishnan-Korepin (GRK) algorithm. The target block can be further partitioned into sub-blocks so that GRK's can be performed in a sequence called a hierarchy. We study the Grover search and GRK partial search in detail and prove that a GRK hierarchy is less efficient than a direct GRK partial search. Both the Grover search and the GRK partial search can be generalized to the case with several target items (or target blocks for a GRK). The GRK partial search algorithm can also be represented in terms of group theory.

Korepin, Vladimir E.; Xu, Ying

302

Parallel Environment for Quantum Computing  

NASA Astrophysics Data System (ADS)

To facilitate numerical study of noise and decoherence in QC algorithms,and of the efficacy of error correction schemes, we have developed a Fortran 90 quantum computer simulator with parallel processing capabilities. It permits rapid evaluation of quantum algorithms for a large number of qubits and for various ``noise'' scenarios. State vectors are distributed over many processors, to employ a large number of qubits. Parallel processing is implemented by the Message-Passing Interface protocol. A description of how to spread the wave function components over many processors, along with how to efficiently describe the action of general one- and two-qubit operators on these state vectors will be delineated.Grover's search and Shor's factoring algorithms with noise will be discussed as examples. A major feature of this work is that concurrent versions of the algorithms can be evaluated with each version subject to diverse noise effects, corresponding to solving a stochastic Schrodinger equation. The density matrix for the ensemble of such noise cases is constructed using parallel distribution methods to evaluate its associated entropy. Applications of this powerful tool is made to delineate the stability and correction of QC processes using Hamiltonian based dynamics.

Tabakin, Frank; Diaz, Bruno Julia

2009-03-01

303

Direct Current Transformer.  

National Technical Information Service (NTIS)

A direct current transformer was built in which the primary consists of an elongated strip of superconductive material, across the ends of which is applied a direct current potential. Parallel and closely spaced to the primary is positioned a transformer ...

E. W. Urban S. M. Khanna

1977-01-01

304

Parallel digital forensics infrastructure.  

SciTech Connect

This report documents the architecture and implementation of a Parallel Digital Forensics infrastructure. This infrastructure is necessary for supporting the design, implementation, and testing of new classes of parallel digital forensics tools. Digital Forensics has become extremely difficult with data sets of one terabyte and larger. The only way to overcome the processing time of these large sets is to identify and develop new parallel algorithms for performing the analysis. To support algorithm research, a flexible base infrastructure is required. A candidate architecture for this base infrastructure was designed, instantiated, and tested by this project, in collaboration with New Mexico Tech. Previous infrastructures were not designed and built specifically for the development and testing of parallel algorithms. With the size of forensics data sets only expected to increase significantly, this type of infrastructure support is necessary for continued research in parallel digital forensics. This report documents the implementation of the parallel digital forensics (PDF) infrastructure architecture and implementation.

Liebrock, Lorie M. (New Mexico Tech, Socorro, NM); Duggan, David Patrick

2009-10-01

305

Exploring parallel algorithms having no serial analogues  

SciTech Connect

The ordering of data acquisitions in many computational problems is an artifact of algorithms developed for serial computers. Often these serial algorithms are highly parallel and thus are mapped directly onto a parallel processing system. This technique, however, does not fully exploit the additional opportunities provided by the system's parallelism. The design of optimal parallel algorithms requires new and different techniques and insights. Unfortunately, parallel performance can still be degraded even with optimal parallel algorithms that preserve the ordering of data access (that is, the data dependences between different computational code blocks) by synchronization primitives, such as locks, events, and barriers. Furthermore, additional decreases in performance are introduced by the various hardware/software components integrated to coordinate the particular parallel processing system. An alternative approach to the class of parallel iterative algorithms is to ignore the ordering of data accesses and allow the computational algorithm to execute asynchronously. These algorithms are referred to as chaotic algorithms and provide programming strategies that would otherwise be too cumbersome to implement and too inefficient to execute on a sequential processor. Although chaotic algorithms are difficult to analyze formally, the comparisons of their observed performance could lead to improved serial and deterministic (nonchaotic) parallel schemes. This paper will examine several chaotic iteration schemes and, based on their results, offer an alternative scheme that substantially improves the serial time to execute this algorithm. 11 refs., 11 figs.

Hiromoto, R.

1988-01-01

306

Natural and Artificial Parallel Computation.  

National Technical Information Service (NTIS)

Contents: The Nature of Parallel Programming; Applications of Parallel Supercomputers: Scientific Results and Computer Science Lessons; Towards General-Purpose Parallel Computers; Cooperative Computation in Brains and Computers; Parallel Systems in the Ce...

O. Simula

1992-01-01

307

Optimistic parallelism requires abstractions  

Microsoft Academic Search

The problem of writing software for multicore processors is greatly simplified if we could automatically parallelize sequential programs. Although auto-parallelization has been studied for many decades, it has succeeded only in a few application areas such as dense matrix computations. In particular, auto-parallelization of irregular programs, which are organized around large, pointer-based data struc- tures like graphs, has seemed intractable.

Milind Kulkarni; Keshav Pingali; Bruce Walter; Ganesh Ramanarayanan; Kavita Bala; L. Paul Chew

2007-01-01

308

Parallel Shortest Lattice Vector Enumeration on Graphics Cards  

Microsoft Academic Search

In this paper we present an algorithm for parallel exhaustive search for short vectors in lattices. This algorithm can be applied to a wide range of parallel computing systems. To illustrate the algorithm, it was implemented on graphics cards using CUDA, a programming frame- work for NVIDIA graphics cards. We gain large speedups compared to previous serial CPU implementations. Our

Jens Hermans; Michael Schneider; Johannes Buchmann; Frederik Vercauteren; Bart Preneel

2010-01-01

309

PCLIPS: Parallel CLIPS  

NASA Technical Reports Server (NTRS)

A parallel version of CLIPS 5.1 has been developed to run on Intel Hypercubes. The user interface is the same as that for CLIPS with some added commands to allow for parallel calls. A complete version of CLIPS runs on each node of the hypercube. The system has been instrumented to display the time spent in the match, recognize, and act cycles on each node. Only rule-level parallelism is supported. Parallel commands enable the assertion and retraction of facts to/from remote nodes working memory. Parallel CLIPS was used to implement a knowledge-based command, control, communications, and intelligence (C(sup 3)I) system to demonstrate the fusion of high-level, disparate sources. We discuss the nature of the information fusion problem, our approach, and implementation. Parallel CLIPS has also be used to run several benchmark parallel knowledge bases such as one to set up a cafeteria. Results show from running Parallel CLIPS with parallel knowledge base partitions indicate that significant speed increases, including superlinear in some cases, are possible.

Hall, Lawrence O.; Bennett, Bonnie H.; Tello, Ivan

1994-01-01

310

Thinking Inside the Box: Comparing Federated Search Results from Google Scholar, Live Search Academic, and Central Search  

Microsoft Academic Search

In a comparison of Google Scholar, Windows Live Search Academic, and Serials Solutions' Central Search, relevant retrieval increases in direct relation to the complexity of the search interface. Central Search, as customized for Florida Gulf Coast University Library, permits far more complex searching than Google Scholar or Windows Academic and performs better than its simpler competitors. However, a close review

Rachel Cooke; Rebecca Donlan

2008-01-01

311

On the Scalability of Parallel UCT  

NASA Astrophysics Data System (ADS)

The parallelization of MCTS across multiple-machines has proven surprisingly difficult. The limitations of existing algorithms were evident in the 2009 Computer Olympiad where Zen using a single four-core machine defeated both Fuego with ten eight-core machines, and Mogo with twenty thirty-two core machines. This paper investigates the limits of parallel MCTS in order to understand why distributed parallelism has proven so difficult and to pave the way towards future distributed algorithms with better scaling. We first analyze the single-threaded scaling of Fuego and find that there is an upper bound on the play-quality improvements which can come from additional search. We then analyze the scaling of an idealized N-core shared memory machine to determine the maximum amount of parallelism supported by MCTS. We show that parallel speedup depends critically on how much time is given to each player. We use this relationship to predict parallel scaling for time scales beyond what can be empirically evaluated due to the immense computation required. Our results show that MCTS can scale nearly perfectly to at least 64 threads when combined with virtual loss, but without virtual loss scaling is limited to just eight threads. We also find that for competition time controls scaling to thousands of threads is impossible not necessarily due to MCTS not scaling, but because high levels of parallelism can start to bump up against the upper performance bound of Fuego itself.

Segal, Richard B.

312

Parallel-META: efficient metagenomic data analysis based on high-performance computation  

PubMed Central

Background Metagenomics method directly sequences and analyses genome information from microbial communities. There are usually more than hundreds of genomes from different microbial species in the same community, and the main computational tasks for metagenomic data analyses include taxonomical and functional component examination of all genomes in the microbial community. Metagenomic data analysis is both data- and computation- intensive, which requires extensive computational power. Most of the current metagenomic data analysis softwares were designed to be used on a single computer or single computer clusters, which could not match with the fast increasing number of large metagenomic projects' computational requirements. Therefore, advanced computational methods and pipelines have to be developed to cope with such need for efficient analyses. Result In this paper, we proposed Parallel-META, a GPU- and multi-core-CPU-based open-source pipeline for metagenomic data analysis, which enabled the efficient and parallel analysis of multiple metagenomic datasets and the visualization of the results for multiple samples. In Parallel-META, the similarity-based database search was parallelized based on GPU computing and multi-core CPU computing optimization. Experiments have shown that Parallel-META has at least 15 times speed-up compared to traditional metagenomic data analysis method, with the same accuracy of the results http://www.computationalbioenergy.org/parallel-meta.html. Conclusion The parallel processing of current metagenomic data would be very promising: with current speed up of 15 times and above, binning would not be a very time-consuming process any more. Therefore, some deeper analysis of the metagenomic data, such as the comparison of different samples, would be feasible in the pipeline, and some of these functionalities have been included into the Parallel-META pipeline.

2012-01-01

313

The Research and Implementation of Parallel Web Crawler in Cluster  

Microsoft Academic Search

As the foundational component of web information acquisition, web crawler has been always the research hotspot in academia and industry, recently the parallel web crawler is the main research direction. In view of the shortage of the center-like dynamic assignment and distributed static assignment which are adopted by current parallel web crawler, this paper presents a parallel web crawler based

Min Wu; Junliang Lai

2010-01-01

314

Automatic management of parallel and distributed system resources  

NASA Technical Reports Server (NTRS)

Viewgraphs on automatic management of parallel and distributed system resources are presented. Topics covered include: parallel applications; intelligent management of multiprocessing systems; performance evaluation of parallel architecture; dynamic concurrent programs; compiler-directed system approach; lattice gaseous cellular automata; and sparse matrix Cholesky factorization.

Yan, Jerry; Ngai, Tin Fook; Lundstrom, Stephen F.

1990-01-01

315

Is searching full text more effective than searching abstracts?  

Microsoft Academic Search

Background: With the growing availability of full-text articles online, scientists and other consumers of the life sciences literature now have the ability to go beyond searching bibliographic records (title, abstract, metadata) to directly access full-text content. Motivated by this emerging trend, I posed the following question: is searching full text more effective than searching abstracts? This question is answered by

Jimmy J. Lin

2009-01-01

316

Distributed game-tree searching  

SciTech Connect

Conventional parallelizations of the alpha-beta ({alpha}{beta}) algorithm have met with limited success. Implementations suffer primarily from the synchronization and search overheads of parallelization. This paper describes a parallel {alpha}{beta} searching program that achieves high performance through the use of four different types of processes: Controllers, Searchers, Table Managers, and Scouts. Synchronization is reduced by having Controller process reassigning idle processes to help out busy ones. Search overhead is reduced by having two types of parallel table management: global Table Managers and the periodic merging and redistribution of local tables. Experiments show that nine processors can achieve 5.67-fold speedups but beyond that, additional processors provide diminishing returns. Given that additional resources are of little benefit, speculative computing is introduced as a means of extending the effective number of processors that can be utilized. Scout processes speculatively search ahead in the tree looking for interesting features and communicate this information back to the {alpha}{beta} program. In this way, the effective search depth is extended. These ideas have been tested experimentally and empirically as part of the chess program ParaPhoenix.

Schaeffer, J. (Computing Science Dept., Univ. of Alberta, Alberta (CA))

1989-02-01

317

A parallel variable metric optimization algorithm  

NASA Technical Reports Server (NTRS)

An algorithm, designed to exploit the parallel computing or vector streaming (pipeline) capabilities of computers is presented. When p is the degree of parallelism, then one cycle of the parallel variable metric algorithm is defined as follows: first, the function and its gradient are computed in parallel at p different values of the independent variable; then the metric is modified by p rank-one corrections; and finally, a single univariant minimization is carried out in the Newton-like direction. Several properties of this algorithm are established. The convergence of the iterates to the solution is proved for a quadratic functional on a real separable Hilbert space. For a finite-dimensional space the convergence is in one cycle when p equals the dimension of the space. Results of numerical experiments indicate that the new algorithm will exploit parallel or pipeline computing capabilities to effect faster convergence than serial techniques.

Straeter, T. A.

1973-01-01

318

Planarity Testing in Parallel  

Microsoft Academic Search

We present a parallel algorithm based on open ear decomposition to con- struct an embedding of a graph onto the plane or report that the graph is nonpla- nar. Our parallel algorithm runs on a CRCW PRAM in logarithmic time with a number of processors bounded by that needed for finding connected components in a graph and for performing bucket

Vijaya Ramachandran; John H. Reif

1994-01-01

319

Parallelization of thermochemical nanolithography.  

PubMed

One of the most pressing technological challenges in the development of next generation nanoscale devices is the rapid, parallel, precise and robust fabrication of nanostructures. Here, we demonstrate the possibility to parallelize thermochemical nanolithography (TCNL) by employing five nano-tips for the fabrication of conjugated polymer nanostructures and graphene-based nanoribbons. PMID:24337109

Carroll, Keith M; Lu, Xi; Kim, Suenne; Gao, Yang; Kim, Hoe-Joon; Somnath, Suhas; Polloni, Laura; Sordan, Roman; King, William P; Curtis, Jennifer E; Riedo, Elisa

2014-01-16

320

The Nas Parallel Benchmarks  

Microsoft Academic Search

A new set of benchmarks has been developed for the performance evaluation of highly parallel supercomputers. These benchmarks consist of five parallel kernels and three simulated application benchmarks. Together theymimic the computation and data movement characteristics of large scale computational fluid dynamics (CFD) applications.The principal distinguishing feature of these benchmarks is their penciland paper specification---all details of these benchmarks are

D. Bailey; E. Barszcz; J. Barton; D. Browning; R. Carter; L. Dagum

1994-01-01

321

Parallel texture caching  

Microsoft Academic Search

The creation of high-quality images requires new functionality and higher performance in real-time graphics architectures. In terms of functionality, texture mapping has become an integral component of graphics systems, and in terms of performance, parallel techniques are used at all stages of the graphics pipeline. In rasterization, texture caching has become prevalent for reduc- ing texture bandwidth requirements. However, parallel

Homan Igehy; Matthew Eldridge; Pat Hanrahan

1999-01-01

322

Impact of a nurse-directed, coordinated school health program to enhance physical activity behaviors and reduce body mass index among minority children: A parallel-group, randomized control trial  

PubMed Central

Background Underserved children, particularly girls and those in urban communities, do not meet the recommended physical activity guidelines (>60 min of daily physical activity), and this behavior can lead to obesity. The school years are known to be a critical period in the life course for shaping attitudes and behaviors. Children look to schools for much of their access to physical activity. Thus, through the provision of appropriate physical activity programs, schools have the power to influence apt physical activity choices, especially for underserved children where disparities in obesity-related outcomes exist. Objectives To evaluate the impact of a nurse directed, coordinated, culturally sensitive, school-based, family-centered lifestyle program on activity behaviors and body mass index. Design, settings and participants: This was a parallel group, randomized controlled trial utilizing a community-based participatory research approach, through a partnership with a University and 5 community schools. Participants included 251 children ages 8–12 from elementary schools in urban, low-income neighborhoods in Los Angeles, USA. Methods The intervention included Kids N Fitness©, a 6-week program which met weekly to provide 45 min of structured physical activity and a 45 min nutrition education class for parents and children. Intervention sites also participated in school-wide wellness activities, including health and counseling services, staff professional development in health promotion, parental education newsletters, and wellness policies for the provision of healthy foods at the school. The Child and Adolescent Trial for Cardiovascular Health School Physical Activity and Nutrition Student Questionnaire measured physical activity behavior, including: daily physical activity, participation in team sports, attending physical education class, and TV viewing/computer game playing. Anthropometric measures included height, weight, body mass index, resting blood pressure, and waist circumference. Measures were collected at baseline, completion of the intervention phase (4 months), and 12 months post-intervention. Results Significant results for students in the intervention, included for boys decreases in TV viewing; and girls increases in daily physical activity, physical education class attendance, and decreases in body mass index z-scores from baseline to the 12 month follow-up. Conclusions Our study shows the value of utilizing nurses to implement a culturally sensitive, coordinated, intervention to decrease disparities in activity and TV viewing among underserved girls and boys.

Wright, Kynna; Giger, Joyce Newman; Norris, Keth; Suro, Zulma

2013-01-01

323

Tabu Search  

Microsoft Academic Search

This article explores the meta-heuristic approach called tabu search, which is dramatically changing our ability to solve a host of problems in applied science, business and engineering. Tabu search has important links to evolutionary and \\

Fred Glover; Manuel Laguna

2003-01-01

324

Savvy Searching.  

ERIC Educational Resources Information Center

Explains desktop metasearch engines, which search the databases of several search engines simultaneously. Reviews two particular versions, the Copernic 2001 Pro and the BullsEye Pro 3, comparing costs, subject categories, display capabilities, and layout for presenting results. (LRW)

Jacso, Peter

2002-01-01

325

Parallel computing works  

SciTech Connect

An account of the Caltech Concurrent Computation Program (C{sup 3}P), a five year project that focused on answering the question: Can parallel computers be used to do large-scale scientific computations '' As the title indicates, the question is answered in the affirmative, by implementing numerous scientific applications on real parallel computers and doing computations that produced new scientific results. In the process of doing so, C{sup 3}P helped design and build several new computers, designed and implemented basic system software, developed algorithms for frequently used mathematical computations on massively parallel machines, devised performance models and measured the performance of many computers, and created a high performance computing facility based exclusively on parallel computers. While the initial focus of C{sup 3}P was the hypercube architecture developed by C. Seitz, many of the methods developed and lessons learned have been applied successfully on other massively parallel architectures.

Not Available

1991-10-23

326

Nearest Neighbor Searching in Binary Search Trees: Simulation of a Multiprocessor System.  

ERIC Educational Resources Information Center

Describes the simulation of a nearest neighbor searching algorithm for document retrieval using a pool of microprocessors. Three techniques are described which allow parallel searching of a binary search tree as well as a PASCAL-based system, PASSIM, which can simulate these techniques. Fifty-six references are provided. (Author/LRW)

Stewart, Mark; Willett, Peter

1987-01-01

327

Search Engines  

Microsoft Academic Search

If you want to find anything on the World Wide Web (WWW), you need to know about search engines. Hitherto, both Internet sceptics and ‘technophobes’ have criticised the various search engines for having the same failings as the WWW itself: that the overall quality and relevance of sites are poor. After all, what search engines retrieve for you is merely

Rustam Al-Shahi

2001-01-01

328

Dewey Searches!  

ERIC Educational Resources Information Center

Describes an activity for young children that helps them conduct subject searches using an automated system that allows customization of access to a library's collection. Explains a timed game that makes use of subject searching and word searching on the topic of dinosaurs. (LRW)

School Library Media Activities Monthly, 2000

2000-01-01

329

Parallel Programming and Parallel Abstractions in Fortress  

Microsoft Academic Search

\\u000a The Programming Language Research Group at Sun Microsystems Laboratories seeks to apply lessons learned from the Java (TM)\\u000a Programming Language to the next generation of programming languages. The Java language supports platform-independent parallel\\u000a programming with explicit multithreading and explicit locks. As part of the DARPA program for High Productivity Computing\\u000a Systems, we are developing Fortress, a language intended to support

Guy L. Steele Jr.

2006-01-01

330

Compositional C++: Compositional Parallel Programming  

Microsoft Academic Search

A compositional parallel program is a program constructed by composing component programs in parallel, where the composed program inherits properties of its components. In this paper, we describe a small extension of C++ called Compositional C++ or CC++ which is an object-oriented notation that supports compositional parallel programming. CC++ integrates different paradigms of parallel programming: data-parallel, task-parallel and object-parallel paradigms;

K. Mani Chandy; Carl Kesselman

1992-01-01

331

Parallel nearest neighbor calculations  

NASA Astrophysics Data System (ADS)

We are just starting to parallelize the nearest neighbor portion of our free-Lagrange code. Our implementation of the nearest neighbor reconnection algorithm has not been parallelizable (i.e., we just flip one connection at a time). In this paper we consider what sort of nearest neighbor algorithms lend themselves to being parallelized. For example, the construction of the Voronoi mesh can be parallelized, but the construction of the Delaunay mesh (dual to the Voronoi mesh) cannot because of degenerate connections. We will show our most recent attempt to tessellate space with triangles or tetrahedrons with a new nearest neighbor construction algorithm called DAM (Dial-A-Mesh). This method has the characteristics of a parallel algorithm and produces a better tessellation of space than the Delaunay mesh. Parallel processing is becoming an everyday reality for us at Los Alamos. Our current production machines are Cray YMPs with 8 processors that can run independently or combined to work on one job. We are also exploring massive parallelism through the use of two 64K processor Connection Machines (CM2), where all the processors run in lock step mode. The effective application of 3-D computer models requires the use of parallel processing to achieve reasonable "turn around" times for our calculations.

Trease, Harold

332

The NAS parallel benchmarks  

NASA Technical Reports Server (NTRS)

A new set of benchmarks was developed for the performance evaluation of highly parallel supercomputers. These benchmarks consist of a set of kernels, the 'Parallel Kernels,' and a simulated application benchmark. Together they mimic the computation and data movement characteristics of large scale computational fluid dynamics (CFD) applications. The principal distinguishing feature of these benchmarks is their 'pencil and paper' specification - all details of these benchmarks are specified only algorithmically. In this way many of the difficulties associated with conventional benchmarking approaches on highly parallel systems are avoided.

Bailey, David (editor); Barton, John (editor); Lasinski, Thomas (editor); Simon, Horst (editor)

1993-01-01

333

Parallel algorithm for dominant points correspondences in robot binocular stereo vision  

NASA Technical Reports Server (NTRS)

This paper presents an algorithm to find the correspondences of points representing dominant feature in robot stereo vision. The algorithm consists of two main steps: dominant point extraction and dominant point matching. In the feature extraction phase, the algorithm utilizes the widely used Moravec Interest Operator and two other operators: the Prewitt Operator and a new operator called Gradient Angle Variance Operator. The Interest Operator in the Moravec algorithm was used to exclude featureless areas and simple edges which are oriented in the vertical, horizontal, and two diagonals. It was incorrectly detecting points on edges which are not on the four main directions (vertical, horizontal, and two diagonals). The new algorithm uses the Prewitt operator to exclude featureless areas, so that the Interest Operator is applied only on the edges to exclude simple edges and to leave interesting points. This modification speeds-up the extraction process by approximately 5 times. The Gradient Angle Variance (GAV), an operator which calculates the variance of the gradient angle in a window around the point under concern, is then applied on the interesting points to exclude the redundant ones and leave the actual dominant ones. The matching phase is performed after the extraction of the dominant points in both stereo images. The matching starts with dominant points in the left image and does a local search, looking for corresponding dominant points in the right image. The search is geometrically constrained the epipolar line of the parallel-axes stereo geometry and the maximum disparity of the application environment. If one dominant point in the right image lies in the search areas, then it is the corresponding point of the reference dominant point in the left image. A parameter provided by the GAV is thresholded and used as a rough similarity measure to select the corresponding dominant point if there is more than one point the search area. The correlation is used as a final decision tool when there is still more than one point in the search area. If there is no dominant point in the search area of if the points in the search area are below a correlation threshold, then the dominant point in the reference image is occluded and can not be corresponded. The algorithm has been modeled, implemented and shown to be fast, robust and parallel. The parallelism is created from three main features: locality of the operators; a memory optimization scheme; and the ability to fully parallelize the extraction phase which is the most computational intensive task in the algorithm. The last feature is achieved by performing the extraction phase on the two images simultaneously.

Al-Tammami, A.; Singh, B.

1993-01-01

334

Parallel processing for scientific computations  

NASA Technical Reports Server (NTRS)

The main contribution of the effort in the last two years is the introduction of the MOPPS system. After doing extensive literature search, we introduced the system which is described next. MOPPS employs a new solution to the problem of managing programs which solve scientific and engineering applications on a distributed processing environment. Autonomous computers cooperate efficiently in solving large scientific problems with this solution. MOPPS has the advantage of not assuming the presence of any particular network topology or configuration, computer architecture, or operating system. It imposes little overhead on network and processor resources while efficiently managing programs concurrently. The core of MOPPS is an intelligent program manager that builds a knowledge base of the execution performance of the parallel programs it is managing under various conditions. The manager applies this knowledge to improve the performance of future runs. The program manager learns from experience.

Alkhatib, Hasan S.

1991-01-01

335

Cloud parallel processing of tandem mass spectrometry based proteomics data.  

PubMed

Data analysis in mass spectrometry based proteomics struggles to keep pace with the advances in instrumentation and the increasing rate of data acquisition. Analyzing this data involves multiple steps requiring diverse software, using different algorithms and data formats. Speed and performance of the mass spectral search engines are continuously improving, although not necessarily as needed to face the challenges of acquired big data. Improving and parallelizing the search algorithms is one possibility; data decomposition presents another, simpler strategy for introducing parallelism. We describe a general method for parallelizing identification of tandem mass spectra using data decomposition that keeps the search engine intact and wraps the parallelization around it. We introduce two algorithms for decomposing mzXML files and recomposing resulting pepXML files. This makes the approach applicable to different search engines, including those relying on sequence databases and those searching spectral libraries. We use cloud computing to deliver the computational power and scientific workflow engines to interface and automate the different processing steps. We show how to leverage these technologies to achieve faster data analysis in proteomics and present three scientific workflows for parallel database as well as spectral library search using our data decomposition programs, X!Tandem and SpectraST. PMID:22916831

Mohammed, Yassene; Mostovenko, Ekaterina; Henneman, Alex A; Marissen, Rob J; Deelder, André M; Palmblad, Magnus

2012-10-01

336

New Parallel Sorting Schemes.  

National Technical Information Service (NTIS)

This paper describes a family of parallel sorting algorithms for a multiprocessor system. These algorithms are enumeration sorts and comprise the following phases: count acquisition: the keys are subdivided into subsets and for each key the number of smal...

F. P. Preparata

1977-01-01

337

Parallel programming with PCN  

SciTech Connect

PCN is a system for developing and executing parallel programs. It comprises a high-level programming language, tools for developing and debugging programs in this language, and interfaces to Fortran and C that allow the reuse of existing code in multilingual parallel programs. Programs developed using PCN are portable across many different workstations, networks, and parallel computers. This document provides all the information required to develop parallel programs with the PCN programming system. In includes both tutorial and reference material. It also presents the basic concepts that underly PCN, particularly where these are likely to be unfamiliar to the reader, and provides pointers to other documentation on the PCN language, programming techniques, and tools. PCN is in the public domain. The latest version of both the software and this manual can be obtained by anonymous FTP from Argonne National Laboratory in the directory pub/pcn at info.mcs.anl.gov (c.f. Appendix A).

Foster, I.; Tuecke, S.

1991-12-01

338

Parallel RC Circuits.  

National Technical Information Service (NTIS)

Reviews the operation of parallel rc circuit and specifically points out how to solve for branch currents and total impedance by using ohm's law. Reviews vector representations and shows how approximate total current and phase angle are found by measuring...

1994-01-01

339

Parallel programming with PCN  

SciTech Connect

PCN is a system for developing and executing parallel programs. It comprises a high-level programming language, a set of tools for developing and debugging programs in this language, and interfaces to Fortran and C that allow the reuse of existing code in multilingual parallel programs. Programs developed using PCN are portable across many different workstations, networks, and parallel computers. This document provides all the information required to develop parallel programs with the PCN programming system. It includes both tutorial and reference material. It also presents the basic concepts that underlie PCN, particularly where these are likely to be unfamiliar to the reader, and provides pointers to other documentation on the PCN language, programming techniques, and tools. PCN is in the public domain. The latest version of both the software and this manual can be obtained by anonymous FTP from Argonne National Laboratory at info.mcs.anl.gov.

Foster, I.; Tuecke, S.

1991-09-01

340

Parallelization of thermochemical nanolithography  

NASA Astrophysics Data System (ADS)

One of the most pressing technological challenges in the development of next generation nanoscale devices is the rapid, parallel, precise and robust fabrication of nanostructures. Here, we demonstrate the possibility to parallelize thermochemical nanolithography (TCNL) by employing five nano-tips for the fabrication of conjugated polymer nanostructures and graphene-based nanoribbons.One of the most pressing technological challenges in the development of next generation nanoscale devices is the rapid, parallel, precise and robust fabrication of nanostructures. Here, we demonstrate the possibility to parallelize thermochemical nanolithography (TCNL) by employing five nano-tips for the fabrication of conjugated polymer nanostructures and graphene-based nanoribbons. Electronic supplementary information (ESI) available: Details on the cantilevers array, on the sample preparation, and on the GO AFM experiments. See DOI: 10.1039/c3nr05696a

Carroll, Keith M.; Lu, Xi; Kim, Suenne; Gao, Yang; Kim, Hoe-Joon; Somnath, Suhas; Polloni, Laura; Sordan, Roman; King, William P.; Curtis, Jennifer E.; Riedo, Elisa

2014-01-01

341

Series and Parallel Circuits  

NSDL National Science Digital Library

In this activity, learners demonstrate and discuss simple circuits as well as the differences between parallel and serial circuit design and functions. Learners test two different circuit designs through the use of low voltage light bulbs.

Ieee

2013-08-30

342

Scalable parallel communications  

NASA Technical Reports Server (NTRS)

Coarse-grain parallelism in networking (that is, the use of multiple protocol processors running replicated software sending over several physical channels) can be used to provide gigabit communications for a single application. Since parallel network performance is highly dependent on real issues such as hardware properties (e.g., memory speeds and cache hit rates), operating system overhead (e.g., interrupt handling), and protocol performance (e.g., effect of timeouts), we have performed detailed simulations studies of both a bus-based multiprocessor workstation node (based on the Sun Galaxy MP multiprocessor) and a distributed-memory parallel computer node (based on the Touchstone DELTA) to evaluate the behavior of coarse-grain parallelism. Our results indicate: (1) coarse-grain parallelism can deliver multiple 100 Mbps with currently available hardware platforms and existing networking protocols (such as Transmission Control Protocol/Internet Protocol (TCP/IP) and parallel Fiber Distributed Data Interface (FDDI) rings); (2) scale-up is near linear in n, the number of protocol processors, and channels (for small n and up to a few hundred Mbps); and (3) since these results are based on existing hardware without specialized devices (except perhaps for some simple modifications of the FDDI boards), this is a low cost solution to providing multiple 100 Mbps on current machines. In addition, from both the performance analysis and the properties of these architectures, we conclude: (1) multiple processors providing identical services and the use of space division multiplexing for the physical channels can provide better reliability than monolithic approaches (it also provides graceful degradation and low-cost load balancing); (2) coarse-grain parallelism supports running several transport protocols in parallel to provide different types of service (for example, one TCP handles small messages for many users, other TCP's running in parallel provide high bandwidth service to a single application); and (3) coarse grain parallelism will be able to incorporate many future improvements from related work (e.g., reduced data movement, fast TCP, fine-grain parallelism) also with near linear speed-ups.

Maly, K.; Khanna, S.; Overstreet, C. M.; Mukkamala, R.; Zubair, M.; Sekhar, Y. S.; Foudriat, E. C.

1992-01-01

343

Greedy Randomized Adaptive Search Procedures  

Microsoft Academic Search

Today, a variety of heuristic approaches are available to the operations research practitioner. One methodology that has a strong intuitive appeal, a prominent empirical track record, and is trivial to efficiently implement on parallel processors is GRASP (Greedy Randomized Adaptive Search Procedures). GRASP is an iterative randomized sampling technique in which each iteration provides a solution to the problem at

Thomas A. Feo; Mauricio G. C. Resende

1995-01-01

344

A Programmable Preprocessor for Parallelizing Fortran-90  

SciTech Connect

A programmable preprocessor that generates portable and efficient parallel Fortran-90 code has been successfully used in the development of a variety of environmental transport simulators for the Department of Energy. The tool provides the basic functionality of a traditional preprocessor where directives are embedded in a serial Fortran program and interpreted by the preprocessor to produce parallel Fortran code with MPI calls. The unique aspect of this work is that the user can make additions to, or modify, these directives. The directives reside in a preprocessor library and changes to this library can range from small changes to customize an existing library, to larger changes for porting a library, to completely replacing the library. The preprocessor is programmed with a library of directives written in a C-like language, called DL, that has added support for manipulating Fortran code fragments. The primary benefits to the user are twofold: It is fairly easy for any user to generate efficient, parallel code from Fortran-90 with embedded directives, and the long term viability of the user?s software is guaranteed. This is because the source code will always run on a serial machine (the directives are transparent to standard Fortran compilers), and the preprocessor library can be modified to work with different hardware and software environments. A 4000 line preprocessor library has been written and used to parallelize roughly 50,000 lines of groundwater modeling code. The programs have been ported to a wide range of parallel architectures. Performance of these programs is similar to programs explicitly written for a parallel machine. Binaries of the preprocessor core, as well as the preprocessor library source code used in our groundwater modeling codes are currently available.

Rosing, Matthew; Yabusaki, Steven B.

1999-07-01

345

A Parallel Hybrid Heuristic for the TSP  

Microsoft Academic Search

In this paper we investigate the design of a coarse-grained parallel implementation of Cga-LK, a hybrid heuristic for the Traveling Salesman Problem (TSP). Cga-LK exploits a compact genetic algorithm in order to generate high-quality tours which are then rened by means of an ecient implementation of the Lin-Kernighan local search heuristic. The results of several experiments conducted on a cluster

Ranieri Baraglia; José Ignacio Hidalgo; Raffaele Perego

2001-01-01

346

The Paradyn parallel performance measurement tools  

Microsoft Academic Search

Abstract Paradyn is a performance,measurement,tool for parallel and distributed programs. Paradyn uses several novel technologies so that it scales to long running programs and large systems, and automates much of the search for performance,bottlenecks. Paradyn is based on a dynamic,notion of performance,instrumentation and measurement.,Application programs are placed into execution and then performance,instrumentation is inserted into the running programs,and modified,during execution.

Barton P. Miller; Mark D. Callaghan; Jonathan M. Cargille; Jeffrey K. Hollingsworth; R. Bruce Irvin; Karen L. Karavanic; Krishna Kunchithapadam; Tia Newhall

1994-01-01

347

Hierarchical Quantum Search  

NASA Astrophysics Data System (ADS)

Database search has wide applications and is used as a subroutine in many important algorithms. In this paper, we will consider a database with a single target item. Quantum algorithm (Grover) locates the target item faster than any classical algorithm. In addition to a full (Grover) search, it frequently occurs that one is looking for a group of items (a block) containing the target item, rather than the target item itself. This problem is known as partial search. As a generalization of the full search, partial search is of particular importance in practice. Partial search trades accuracy for speed, i.e., it works faster than a full search. There exists different versions of partial search. We will study the optimized version of the algorithm discovered by Grover and Radhakrishnan and call it GRK. GRK can be applied successively (in a sequence). First, the database is partitioned into blocks and GRK is applied to find the target block. This target block is then partitioned into subblocks and GRK is used again to find the target subblock. This procedure can be repeated if the database is large enough. (This sequence of GRK's is called a hierarchy.) Another possibility is to partition the database into subblocks directly and use GRK to find the target subblock once. In this paper, we will prove that the latter is faster (makes less queries to the Oracle).

Korepin, Vladimir E.; Xu, Ying

348

Hierarchical Quantum Search  

NASA Astrophysics Data System (ADS)

Database search has wide applications and is used as a subroutine in many important algorithms. In this paper we will consider a database with a single target item. Quantum algorithm [Grover] locates the target item faster than any classical algorithm. In addition to a full [Grover] search, it frequently occurs that one is looking for a group of items [a block] containing the target item, rather than the target item itself. This problem is known as partial search. As a generalization of the full search, partial search is of particular importance in practice. Partial search trades accuracy for speed, i.e. it works faster than a full search. There exists different versions of partial search. We will study the optimized version of the algorithm discovered by Grover and Radhakrishnan and call it GRK. GRK can be applied successively [in a sequence]. First the database is partitioned into blocks and GRK is applied to find the target block. Then this target block is partitioned into sub-blocks and GRK is used again to find the target sub-block. This procedure can be repeated if the database is large enough. [This sequence of GRK's is called a hierarchy.] Another possibility is to partition the database into sub-blocks directly and use GRK to find the target sub-block once. In this paper we will prove that the latter is faster [makes less queries to the oracle].

Korepin, Vladimir E.; Xu, Ying

2008-12-01

349

Code Parallelization with CAPO: A User Manual  

NASA Technical Reports Server (NTRS)

A software tool has been developed to assist the parallelization of scientific codes. This tool, CAPO, extends an existing parallelization toolkit, CAPTools developed at the University of Greenwich, to generate OpenMP parallel codes for shared memory architectures. This is an interactive toolkit to transform a serial Fortran application code to an equivalent parallel version of the software - in a small fraction of the time normally required for a manual parallelization. We first discuss the way in which loop types are categorized and how efficient OpenMP directives can be defined and inserted into the existing code using the in-depth interprocedural analysis. The use of the toolkit on a number of application codes ranging from benchmark to real-world application codes is presented. This will demonstrate the great potential of using the toolkit to quickly parallelize serial programs as well as the good performance achievable on a large number of toolkit to quickly parallelize serial programs as well as the good performance achievable on a large number of processors. The second part of the document gives references to the parameters and the graphic user interface implemented in the toolkit. Finally a set of tutorials is included for hands-on experiences with this toolkit.

Jin, Hao-Qiang; Frumkin, Michael; Yan, Jerry; Biegel, Bryan (Technical Monitor)

2001-01-01

350

Parallel Open Ear Decomposition with Applications to Graph Biconnectivity and Triconnectivity  

Microsoft Academic Search

This report deals with a parallel algorithmic technique that has proved tobe very useful in the design of efficient parallel algorithms for several problemson undirected graphs. We describe this method for searching undirectedgraphs, called "open ear decomposition", and we relate this decomposition tograph biconnectivity. We present an efficient parallel algorithm for finding thisdecomposition and we relate it to a sequential

Vijaya Ramachandran

1993-01-01

351

Serial Deployment of Attention During Visual Search  

Microsoft Academic Search

This study examined whether objects are attended in serial or in parallel during a demanding visual search task. A component of the event-related potential waveform, the N2pc wave, was used as a continuous measure of the allocation of attention to possible targets in the search arrays. Experiment 1 demonstrated that the relative allocation of attention shifts rapidly, favoring one item

Geoffrey F. Woodman; Steven J. Luck

2003-01-01

352

PDDP: A data parallel programming model. Revision 1  

SciTech Connect

PDDP, the Parallel Data Distribution Preprocessor, is a data parallel programming model for distributed memory parallel computers. PDDP impelments High Performance Fortran compatible data distribution directives and parallelism expressed by the use of Fortran 90 array syntax, the FORALL statement, and the (WRERE?) construct. Distribued data objects belong to a global name space; other data objects are treated as local and replicated on each processor. PDDP allows the user to program in a shared-memory style and generates codes that are portable to a variety of parallel machines. For interprocessor communication, PDDP uses the fastest communication primitives on each platform.

Warren, K.H.

1995-06-01

353

Sublattice parallel replica dynamics  

NASA Astrophysics Data System (ADS)

Exascale computing presents a challenge for the scientific community as new algorithms must be developed to take full advantage of the new computing paradigm. Atomistic simulation methods that offer full fidelity to the underlying potential, i.e., molecular dynamics (MD) and parallel replica dynamics, fail to use the whole machine speedup, leaving a region in time and sample size space that is unattainable with current algorithms. In this paper, we present an extension of the parallel replica dynamics algorithm [A. F. Voter, Phys. Rev. B 57, R13985 (1998), 10.1103/PhysRevB.57.R13985] by combining it with the synchronous sublattice approach of Shim and Amar [Y. Shim and J. G. Amar, Phys. Rev. B 71, 125432 (2005), 10.1103/PhysRevB.71.125432], thereby exploiting event locality to improve the algorithm scalability. This algorithm is based on a domain decomposition in which events happen independently in different regions in the sample. We develop an analytical expression for the speedup given by this sublattice parallel replica dynamics algorithm and compare it with parallel MD and traditional parallel replica dynamics. We demonstrate how this algorithm, which introduces a slight additional approximation of event locality, enables the study of physical systems unreachable with traditional methodologies and promises to better utilize the resources of current high performance and future exascale computers.

Martínez, Enrique; Uberuaga, Blas P.; Voter, Arthur F.

2014-06-01

354

A feasibility study of multiplexing parallel beam.  

PubMed

Single-photon emission computed tomography (SPECT) is a suitable tool for clinically localizing deep-sited tumors; SPECT with high spatial resolution has the ability to localize deep-sited tumors precisely. However, because of its poor sensitivity, in China SPECT now only plays a complementary role. To improve the sensitivity of the parallel beam collimator mainly used in China, a multiplexing parallel beam collimator is proposed, which can improve sensitivity while maintaining higher spatial resolution by using theoretical prediction and Monte Carlo simulation. The improved sensitivity-to-spatial resolution ratio has an optimal value. In addition, a set of gamma ray channels, introduced only in the transverse direction, did not have any effect in the axial direction. In the transverse direction, the projection data are the sum of the parallel beam and two oblique parallel beams. From visual assessment obtained using computer simulations with equal sensitivity, the reconstructed image at deep-sited was noticeably better than that with the high sensitivity parallel beam. PMID:23402796

Ma, Jiayi; Zhao, Jingwu; Shi, Xiaodong; Huang, Runshen

2013-05-01

355

Scalable Parallel Matrix Multiplication on Distributed Memory Parallel Computers  

Microsoft Academic Search

Consider any known sequential algorithm for matrix multipli- cation over an arbitrary ring with time complexity ,w here . We show that such an algorithm can be parallelized on a distributed memory parallel computer (DMPC) in time by using processors. Such a parallel computation is cost optimal and matches the performance of PRAM. Further- more, our parallelization on a DMPC

Keqin Li

2000-01-01

356

Modeling search engine effectiveness for federated search  

Microsoft Academic Search

Federated search links multiple search engines into a single, virtual search system. Most prior research of federated search focused on selecting search engines that have the most relevant contents, but ignored the retrieval effectiveness of individual search engines. This omission can cause serious problems when federating search engines of different qualities.This paper proposes a federated search technique that uses utility

Luo Si; Jamie Callan

2005-01-01

357

SMM observations of gamma-ray transients. 3: A search for a broadened, redshifted positron annihilation line from the direction of the Galactic center  

NASA Technical Reports Server (NTRS)

We have searched for 1980-1988 Solar Maximum Mission gamma-ray spectrometer data for transient emission on timescales from hours to approximately 12 days of broad gamma-ray lines at energies approximately 400 keV, which were reported by the High Energy Astronomy Observatory (HEAO) 1 and SIGMA experiments from two sources lying toward the Galactic center. The lines have been interpreted as the product of the annihilation of positrons in pair plasmas surrounding the black hole candidate 1E 1740.7-2942 and the X-ray binary 1H 1822-371. Our results from a combined exposure of approximately 1.5 x 10(exp 7)s provide no convincing evidence for transient emission of this line on any timescale between approximately 9 hr and approximately 1 yr. Our 3 sigma upper limits on the line flux during approximately 12 day intervals are characteristically 4.8 x 10(exp -3) photon/sq cm/s, while for approximately 1 day intervals our 3 sigma upper limits are characteristically 4.9 x 10(exp -3) photon/sq cm/s. These results imply a duty cycle of less than 1.3% for the transient line measured from 1H 1822-371 during a approximately 3 week interval in 1977 by HEAO 1, and a duty cycle of less than or = 0.8% for the transient line detected in 1990 and 1992 from 1E 1740.7-2942 on approximately 1 day timescales by SIGMA.

Harris, Michael J.; Share, Gerald H.; Leising, Mark D.

1994-01-01

358

Areal coverage of the ocean floor by the deep-sea elasipodid holothurian Oneirophanta mutabilis: estimates using systematic, random and directional search strategy simulations  

NASA Astrophysics Data System (ADS)

Deep-sea sediment can be markedly modified by the activities of the mobile epibenthic megafauna. Among other factors, the scale and rate of such bioturbations will be influenced by the population density, as well as by the pattern and speed of movement of members of such a faunal group. Any attempt to obtain an estimate of the effects of the activity of such groups on the sediment is accompanied by a number of assumptions about their individual mode of movement. We examined the degree to which these estimates depend on the assumed mode of motion. Speed and behaviour data were recovered from a free-vehicle camera for the elasipodid holothurian Oneirophanta mutabilis, a dominant component of the mobile invertebrate megafauna on the Porcupine Abyssal Plain (PAP), northeast Atlantic. Using these data, we developed a number of simulations to determine the time taken by the PAP population of O. mutabilis to cover 50% of the sediment area ( t50%) by differing ranging strategies. At a hypothetical population density of 27.78 indiv. × 10 -3 m -2 using a systematic search, t50% is 12 days whereas for a random ranging strategy, t50% is 17 years. A simulation incorporating observed distributions of speed and angles of turn, hence approximating the actual behaviour of the holothurian, issued a t50% of 9.6 years. The behaviour of the animal is shown to have a profound effect on areal coverage times and consequent rates of bioturbation. Simply multiplying mean speed by swath width is shown to be too simplistic an approach.

Smith, A.; Matthiopoulos, J.; Priede, I. G.

1997-03-01

359

SPINning parallel systems software.  

SciTech Connect

We describe our experiences in using Spin to verify parts of the Multi Purpose Daemon (MPD) parallel process management system. MPD is a distributed collection of processes connected by Unix network sockets. MPD is dynamic processes and connections among them are created and destroyed as MPD is initialized, runs user processes, recovers from faults, and terminates. This dynamic nature is easily expressible in the Spin/Promela framework but poses performance and scalability challenges. We present here the results of expressing some of the parallel algorithms of MPD and executing both simulation and verification runs with Spin.

Matlin, O.S.; Lusk, E.; McCune, W.

2002-03-15

360

Adaptive parallel logic networks  

NASA Technical Reports Server (NTRS)

Adaptive, self-organizing concurrent systems (ASOCS) that combine self-organization with massive parallelism for such applications as adaptive logic devices, robotics, process control, and system malfunction management, are presently discussed. In ASOCS, an adaptive network composed of many simple computing elements operating in combinational and asynchronous fashion is used and problems are specified by presenting if-then rules to the system in the form of Boolean conjunctions. During data processing, which is a different operational phase from adaptation, the network acts as a parallel hardware circuit.

Martinez, Tony R.; Vidal, Jacques J.

1988-01-01

361

Simulating Billion-Task Parallel Programs  

SciTech Connect

In simulating large parallel systems, bottom-up approaches exercise detailed hardware models with effects from simplified software models or traces, whereas top-down approaches evaluate the timing and functionality of detailed software models over coarse hardware models. Here, we focus on the top-down approach and significantly advance the scale of the simulated parallel programs. Via the direct execution technique combined with parallel discrete event simulation, we stretch the limits of the top-down approach by simulating message passing interface (MPI) programs with millions of tasks. Using a timing-validated benchmark application, a proof-of-concept scaling level is achieved to over 0.22 billion virtual MPI processes on 216,000 cores of a Cray XT5 supercomputer, representing one of the largest direct execution simulations to date, combined with a multiplexing ratio of 1024 simulated tasks per real task.

Perumalla, Kalyan S [ORNL] [ORNL; Park, Alfred J [ORNL] [ORNL

2014-01-01

362

Geographical and Topographical Atlas accompanying the report of the Geological Exploration of the Fortieth Parallel, made by authority of the Hornorable Secretary of War, under the direction of Brig. and Bvt. Major General A. A. Humphreys, Chief of Engineers  

USGS Publications Warehouse

Contains a title, legend, and 11 folio maps in the folio. Contains a topographic (shaded) map of Cordilleran region, limiting meridians 104° and 124°; limiting parallels 29° and 50°. Scale, 60 miles to the inch. Also contains four geologic and four topographic (shaded) maps, on scale of 4 miles to the inch, of the following areas: Sheet I. Longitude, 104° 30'-107° 37'; latitude, 40° 20'-41° 54'. Sheet II. Longitude, 107° 37'-110° 43'; latitude, 40° 16'-41° 50'. Sheet III. Longitude, 110° 43'-113° 50'; latitude, 40° 13'-41° 46'. Sheet IV. Longitude, 113° 50'-116° 56'; latitude, 39° 55'-41° 29'.

King, Clarence; Lithography by Bien, Julius

1876-01-01

363

Performance Evaluation in Network-Based Parallel Computing  

NASA Technical Reports Server (NTRS)

Network-based parallel computing is emerging as a cost-effective alternative for solving many problems which require use of supercomputers or massively parallel computers. The primary objective of this project has been to conduct experimental research on performance evaluation for clustered parallel computing. First, a testbed was established by augmenting our existing SUNSPARCs' network with PVM (Parallel Virtual Machine) which is a software system for linking clusters of machines. Second, a set of three basic applications were selected. The applications consist of a parallel search, a parallel sort, a parallel matrix multiplication. These application programs were implemented in C programming language under PVM. Third, we conducted performance evaluation under various configurations and problem sizes. Alternative parallel computing models and workload allocations for application programs were explored. The performance metric was limited to elapsed time or response time which in the context of parallel computing can be expressed in terms of speedup. The results reveal that the overhead of communication latency between processes in many cases is the restricting factor to performance. That is, coarse-grain parallelism which requires less frequent communication between processes will result in higher performance in network-based computing. Finally, we are in the final stages of installing an Asynchronous Transfer Mode (ATM) switch and four ATM interfaces (each 155 Mbps) which will allow us to extend our study to newer applications, performance metrics, and configurations.

Dezhgosha, Kamyar

1996-01-01

364

Visualization of Pulsar Search Data  

NASA Astrophysics Data System (ADS)

The search for periodic signals from rotating neutron stars or pulsars has been a computationally taxing problem to astronomers for more than twenty-five years. Over this time interval, increases in computational capability have allowed ever more sensitive searches, covering a larger parameter space. The volume of input data and the general presence of radio frequency interference typically produce numerous spurious signals. Visualization of the search output and enhanced real-time processing of significant candidate events allow the pulsar searcher to optimally processes and search for new radio pulsars. The pulsar search algorithm and visualization system presented in this paper currently runs on serial RISC based workstations, a traditional vector based super computer, and a massively parallel computer. A description of the serial software algorithm and its modifications for massively parallel computing are describe. The results of four successive searches for millisecond period radio pulsars using the Arecibo telescope at 430 MHz have resulted in the successful detection of new long-period and millisecond period radio pulsars.

Foster, R. S.; Wolszczan, A.

1993-05-01

365

Further results in the search for the direct two-proton decay of ^94Ag^m (J^?= 21^+, 6.7 MeV)  

NASA Astrophysics Data System (ADS)

Both direct one-proton decay and direct two-proton decay of ^94Ag^m from this 0.4 s isomeric state have been reported in experiments utilizing the GSI on-line mass separator [1]. In the latter decay, coincident events between silicon E detectors with a threshold energy of 0.4 MeV and a summed decay energy of 1.9±0.1 MeV were observed with a yield of 350±210 pb in coincidence with ?-decays in the ^92Rh daughter. We utilized our helium-jet system at the LBNL 88-inch cyclotron to repeat this experiment, again employing the ^58Ni(^40Ca,p3n) reaction at 197 MeV. Reaction products were transported via a capillary to a detection area and collected on a slowly rotating wheel in front of an assembly of 24 ?Egas-?Egas-ESi detector telescopes with a threshold of 0.4 MeV for identifying protons. Five of these telescopes observe the 0.79 MeV single proton decay from ^94Ag^m at the reported yield of 1.3 nb. In the 240/276 identified proton detector combinations with low background, no proton-proton coincidences have been observed. Data from the remaining 36 detector combinations require a separate analysis, which is in progress. Monte Carlo analyses of our anticipated proton-proton coincidences for both sets of detector combinations will be presented. ^ 1Mukha et al., Nature 439, 298 (2006).

Cerny, J.; Lee, D. W.; Perajarvi, K.; Moltz, D. M.; Barquest, B. R.; Grossman, L. E.; Jeong, W.; Jewett, C. C.

2008-10-01

366

Data Parallelism and Functional Programming  

Microsoft Academic Search

\\u000aData parallelism is often seen as a form of explicit parallelism for SIMD and vector machines, and data parallel programming as an explicit programming paradigm for these architectures. Data parallel languages possess certain software qualities as well, which justifies their use in higher level programming and specification closer to the algorithm domain. Thus, it is interesting to study how the

Björn Lisper

1996-01-01

367

Parallel Complexity of Matrix Multiplication  

Microsoft Academic Search

Effective design of parallel matrix multiplication algorithms relies on the consideration of many interdependent issues based on the underlying parallel machine or network upon which such algorithms will be implemented, as well as, the type of methodology utilized by an algorithm. In this paper, we determine the parallel complexity of multiplying two (not necessarily square) matrices on parallel distributed-memory machines

Eunice E. Santos

2003-01-01

368

Scalable Parallel Programming with CUDA  

Microsoft Academic Search

The advent of multicore CPUs and manycore GPUs means that mainstream processor chips are now parallel systems. Furthermore, their parallelism continues to scale with Moore's law. The challenge is to develop mainstream application software that transparently scales its parallelism to leverage the increasing number of processor cores, much as 3D graphics applications transparently scale their parallelism to manycore GPUs with

John Nickolls; Ian Buck; Michael Garland; Kevin Skadron

2008-01-01

369

Effective Automatic Parallelization with Polaris  

Microsoft Academic Search

. The Polaris project has delivered a new parallelizing compiler that overcomes severe limitations of current compilers. While available parallelizing compilers may succeed on small kernels, they often fail to extract any meaningful parallelism from large applications. In contrast, Polaris has proven to speed up real programs significantly beyond the degree achieved by the parallelization tools available on the SGI

William Blume; Rudolf Eigenmann; Keith Faigin; John Grout; Jay Hoeflinger; David Padua; Paul Petersen; William Pottenger; Lawrence Rauchwerger; Peng Tu; Stephen Weatherford

1995-01-01

370

Control of parallel manipulators using force feedback  

NASA Technical Reports Server (NTRS)

Two control schemes are compared for parallel robotic mechanisms actuated by hydraulic cylinders. One scheme, the 'rate based scheme', uses the position and rate information only for feedback. The second scheme, the 'force based scheme' feeds back the force information also. The force control scheme is shown to improve the response over the rate control one. It is a simple constant gain control scheme better suited to parallel mechanisms. The force control scheme can be easily modified for the dynamic forces on the end effector. This paper presents the results of a computer simulation of both the rate and force control schemes. The gains in the force based scheme can be individually adjusted in all three directions, whereas the adjustment in just one direction of the rate based scheme directly affects the other two directions.

Nanua, Prabjot

1994-01-01

371

Parallel Spectral Numerical Methods  

NSDL National Science Digital Library

This module teaches the principals of Fourier spectral methods, their utility in solving partial differential equation and how to implement them in code. Performance considerations for several Fourier spectral implementations are discussed and methods for effective scaling on parallel computers are explained.

Chen, Gong; Cloutier, Brandon; Li, Ning; Muite, Benson; Rigge, Paul

372

Parallel Merge Sort  

Microsoft Academic Search

We give a parallel implementation of merge sort on a CREW PRAM that uses n processors and O(logn) time; the constant in the running time is small. We also give a more complex version of the algorithm for the EREW PRAM; it also uses n processors and O(logn) time. The constant in the running time is still moderate, though not

Richard Cole

1986-01-01

373

Parallel programming with PCN  

SciTech Connect

PCN is a system for developing and executing parallel programs. It comprises a high-level programming language, tools for developing and debugging programs in this language, and interfaces to Fortran and Cthat allow the reuse of existing code in multilingual parallel programs. Programs developed using PCN are portable across many different workstations, networks, and parallel computers. This document provides all the information required to develop parallel programs with the PCN programming system. It includes both tutorial and reference material. It also presents the basic concepts that underlie PCN, particularly where these are likely to be unfamiliar to the reader, and provides pointers to other documentation on the PCN language, programming techniques, and tools. PCN is in the public domain. The latest version of both the software and this manual can be obtained by anonymous ftp from Argonne National Laboratory in the directory pub/pcn at info.mcs. ani.gov (cf. Appendix A). This version of this document describes PCN version 2.0, a major revision of the PCN programming system. It supersedes earlier versions of this report.

Foster, I.; Tuecke, S.

1993-01-01

374

Massively parallel processor computer  

NASA Technical Reports Server (NTRS)

An apparatus for processing multidimensional data with strong spatial characteristics, such as raw image data, characterized by a large number of parallel data streams in an ordered array is described. It comprises a large number (e.g., 16,384 in a 128 x 128 array) of parallel processing elements operating simultaneously and independently on single bit slices of a corresponding array of incoming data streams under control of a single set of instructions. Each of the processing elements comprises a bidirectional data bus in communication with a register for storing single bit slices together with a random access memory unit and associated circuitry, including a binary counter/shift register device, for performing logical and arithmetical computations on the bit slices, and an I/O unit for interfacing the bidirectional data bus with the data stream source. The massively parallel processor architecture enables very high speed processing of large amounts of ordered parallel data, including spatial translation by shifting or sliding of bits vertically or horizontally to neighboring processing elements.

Fung, L. W. (inventor)

1983-01-01

375

Remarks on Parallel Analysis.  

ERIC Educational Resources Information Center

Use of parallel analysis (PA), a selection rule for the number-of-factors problem, is investigated from the viewpoint of permutation assessment through a Monte Carlo simulation. Results reveal advantages and limitations of PA. Tables of sample eigenvalues are included. (SLD)

Buja, Andreas; Eyuboglu, Nermin

1992-01-01

376

Parallel and distributed computation  

Microsoft Academic Search

This book focuses on numerical algorithms suited for parallelization for solving systems of equations and optimization problems. Emphasis on relaxation methods of the Jacobi and Gauss-Seidel type, and issues of communication and synchronization. Topics covered include: Algorithms for systems of linear equations and matrix inversion; Herative methods for nonlinear problems; and Shortest paths and dynamic programming.

Dimitri P. Bertsekas; John N. Tsitsiklis

1989-01-01

377

Parallel distributed viewshed analysis  

Microsoft Academic Search

——- ... .. 1. ABSTRACT The paper describes a number of distributed approaches to implementing a parallel vklbility a]g~rithm for Viewshed analysis. The problem can be simplified by considering a range of domain partitioning strategies for optimizing tie proc=sor worldoads. The best approaches are shown to work 22 times faster across a network of 24 processors. Such strategies allow traditional

J. Andrew Ware; David B. Kidner; Philip J. Rallings

1998-01-01

378

Hexagonal Parallel Pattern Transformations  

Microsoft Academic Search

The concept of the two-dimensional (2-D) parallel computer with square module arrays was first introduced by Unger. It is the purpose of this paper to discuss the relative merits of square and hexagonal module arrays, to propose an operational symbolism for the various basic hexagonal modular transformations which may be performed by these comupters, to illustrate some logical circuit implementation,

M. J. E. Golay

1969-01-01

379

Parallel processing and simulation  

Microsoft Academic Search

Summary form only given. High instruction execution rates may be achieved through a vorpal of inexpensive processors operating in parallel. The harnessing of this raw computing power to discrete event simulation applications is an active area of research. Three major approaches to the problem, of assigning computational tasks to processing elements may be identified: (1) model based assignment, (2) local

John C. Comfort; David Jefferson; Y. V. Reddy; Paul Reynolds; Sallie Sheppard

1983-01-01

380

Parallelizing the Data Cube  

Microsoft Academic Search

This paper presents a general methodology for the efficient parallelization of existing data cube construction algorithms. We describe two different partitioning strategies, one for top-down and one for bottom- up cube algorithms. Both partitioning strategies assign subcubes to individual processors in such a way that the loads assigned to the processors are balanced. Our methods reduce inter processor communication overhead

Frank K. H. A. Dehne; Todd Eavis; Susanne E. Hambrusch; Andrew Rau-chaplin

2001-01-01

381

High performance parallel architectures  

SciTech Connect

In this paper the author describes current high performance parallel computer architectures. A taxonomy is presented to show computer architecture from the user programmer's point-of-view. The effects of the taxonomy upon the programming model are described. Some current architectures are described with respect to the taxonomy. Finally, some predictions about future systems are presented. 5 refs., 1 fig.

Anderson, R.E. (Lawrence Livermore National Lab., CA (USA))

1989-09-01

382

Parallel Traveling Salesman Problem  

NSDL National Science Digital Library

The traveling salesman problem is a classic optimization problem in which one seeks to minimize the path taken by a salesman in traveling between N cities, where the salesman stops at each city one and only one time, never retracing his/her route. This implementation is designed to run on UNIX systems with X-Windows, and includes parallelization using MPI.

Joiner, David; Hassinger, Jonathan

383

Compositional parallel programming languages.  

SciTech Connect

In task-parallel programs, diverse activities can take place concurrently, and communication and synchronization patterns are complex and not easily predictable. Previous work has identified compositionality as an important design principle for task-parallel programs. In this article, we discuss alternative approaches to the realization of this principle, which holds that properties of program components should be preserved when those components are composed in parallel with other program components. We review two programming languages, Strand and Program Composition Notation, that support compositionality via a small number of simple concepts, namely, monotone operations on shared objects, a uniform addressing mechanism, and parallel composition. Both languages have been used extensively for large-scale application development, allowing us to provide an informed assessment of both their strengths and their weaknesses. We observe that while compositionality simplifies development of complex applications, the use of specialized languages hinders reuse of existing code and tools and the specification of domain decomposition strategies. This suggests an alternative approach based on small extensions to existing sequential languages. We conclude the article with a discussion of two languages that realized this strategy.

Foster, I.; Mathematics and Computer Science

1996-01-01

384

Parallel Plate Detectors.  

National Technical Information Service (NTIS)

A 5x3cm exp 2 (timing only) and a 15x5cm exp 2 (timing and position) parallel plate avalanche counters (PPAC) are considered. The theory of operation and timing resolution is given. The measurement set-up and the curves of experimental results illustrate ...

D. Gardes P. Volkov

1981-01-01

385

Exoplanet search with astrometry  

Microsoft Academic Search

Searching for extrasolar planets by direct detection is extremely challenging for current instrumentation. Indirect methods, that measure the effect of a planet on its host star, are much more promising and have indeed led to the discovery of nearly all extrasolar planetary systems known today. While the most successful method thus far is the radial velocity technique, new interferometric instruments

Ralf Launhardt; Max Planck

2009-01-01

386

Search Tips  

MedlinePLUS

... What do the links in the 'Refine by Keyword' box mean? The 'Refine by Keyword' box organizes your search results into groups based ... words in quotation marks. For example, "health services research" retrieves pages containing that phrase. Return to top ...

387

Measurement of the B?Xs?+?- Branching Fraction and Search for Direct CP Violation from a Sum of Exclusive Final States  

NASA Astrophysics Data System (ADS)

We measure the total branching fraction of the flavor-changing neutral-current process B?Xs?+?-, along with partial branching fractions in bins of dilepton and hadronic system (Xs) mass, using a sample of 471×106 ?(4S)?BB ¯ events recorded with the BABAR detector. The admixture of charged and neutral B mesons produced at PEP-II2 are reconstructed by combining a dilepton pair with 10 different Xs final states. Extrapolating from a sum over these exclusive modes, we measure a lepton-flavor-averaged inclusive branching fraction B(B?Xs?+?-)=[6.73-0.64+0.70(stat)-0.25+0.34(exp syst)±0.50(model syst)]×10-6 for m?+?-2>0.1 GeV2/c4. Restricting our analysis exclusively to final states from which a decaying B meson's flavor can be inferred, we additionally report measurements of the direct CP asymmetry ACP in bins of dilepton mass; over the full dilepton mass range, we find ACP=0.04±0.11±0.01 for a lepton-flavor-averaged sample.

Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Brown, D. N.; Kerth, L. T.; Kolomensky, Yu. G.; Lee, M. J.; Lynch, G.; Koch, H.; Schroeder, T.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; So, R. Y.; Khan, A.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Kravchenko, E. A.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Yushkov, A. N.; Lankford, A. J.; Mandelkern, M.; Dey, B.; Gary, J. W.; Long, O.; Campagnari, C.; Franco Sevilla, M.; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; West, C. A.; Eisner, A. M.; Lockman, W. S.; Schumm, B. A.; Seiden, A.; Chao, D. S.; Cheng, C. H.; Echenard, B.; Flood, K. T.; Hitlin, D. G.; Miyashita, T. S.; Ongmongkolkul, P.; Porter, F. C.; Andreassen, R.; Huard, Z.; Meadows, B. T.; Pushpawela, B. G.; Sokoloff, M. D.; Sun, L.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Spaan, B.; Schwierz, R.; Bernard, D.; Verderi, M.; Playfer, S.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cibinetto, G.; Fioravanti, E.; Garzia, I.; Luppi, E.; Piemontese, L.; Santoro, V.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Martellotti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Bhuyan, B.; Prasad, V.; Morii, M.; Adametz, A.; Uwer, U.; Lacker, H. M.; Dauncey, P. D.; Mallik, U.; Chen, C.; Cochran, J.; Meyer, W. T.; Prell, S.; Ahmed, H.; Gritsan, A. V.; Arnaud, N.; Davier, M.; Derkach, D.; Grosdidier, G.; Le Diberder, F.; Lutz, A. M.; Malaescu, B.; Roudeau, P.; Stocchi, A.; Wormser, G.; Lange, D. J.; Wright, D. M.; Coleman, J. P.; Fry, J. R.; Gabathuler, E.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Di Lodovico, F.; Sacco, R.; Cowan, G.; Bougher, J.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Griessinger, K.; Hafner, A.; Prencipe, E.; Schubert, K. R.; Barlow, R. J.; Lafferty, G. D.; Cenci, R.; Hamilton, B.; Jawahery, A.; Roberts, D. A.; Cowan, R.; Dujmic, D.; Sciolla, G.; Cheaib, R.; Patel, P. M.; Robertson, S. H.; Biassoni, P.; Neri, N.; Palombo, F.; Cremaldi, L.; Godang, R.; Sonnek, P.; Summers, D. J.; Simard, M.; Taras, P.; De Nardo, G.; Monorchio, D.; Onorato, G.; Sciacca, C.; Martinelli, M.; Raven, G.; Jessop, C. P.; LoSecco, J. M.; Honscheid, K.; Kass, R.; Brau, J.; Frey, R.; Sinev, N. B.; Strom, D.; Torrence, E.; Feltresi, E.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simi, G.; Simonetto, F.; Stroili, R.; Akar, S.; Ben-Haim, E.; Bomben, M.; Bonneaud, G. R.; Briand, H.; Calderini, G.; Chauveau, J.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Sitt, S.; Biasini, M.; Manoni, E.; Pacetti, S.; Rossi, A.; Angelini, C.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Cervelli, A.; Chrzaszcz, M.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Oberhof, B.; Paoloni, E.; Perez, A.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Olsen, J.; Smith, A. J. S.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Li Gioi, L.; Piredda, G.; Bünger, C.; Grünberg, O.; Hartmann, T.; Leddig, T.; Voß, C.; Waldi, R.; Adye, T.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Hamel de Monchenault, G.; Vasseur, G.; Yèche, Ch.; Anulli, F.; Aston, D.; Bard, D. J.; Benitez, J. F.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Ebert, M.; Field, R. C.; Fulsom, B. G.; Gabareen, A. M.; Graham, M. T.; Hast, C.; Innes, W. R.; Kim, P.; Kocian, M. L.; Leith, D. W. G. S.; Lewis, P.; Lindemann, D.; Lindquist, B.; Luitz, S.; Luth, V.; Lynch, H. L.; MacFarlane, D. B.; Muller, D. R.; Neal, H.; Nelson, S.; Perl, M.; Pulliam, T.; Ratcliff, B. N.; Roodman, A.; Salnikov, A. A.; Schindler, R. H.; Snyder, A.; Su, D.; Sullivan, M. K.; Va'vra, J.; Wagner, A. P.; Wang, W. F.; Wisniewski, W. J.; Wittgen, M.; Wright, D. H.; Wulsin, H. W.; Ziegler, V.; Park, W.; Purohit, M. V.; White, R. M.; Wilson, J. R.; Randle-Conde, A.; Sekula, S. J.; Bellis, M.; Burchat, P. R.; Puccio, E. M. T.; Alam, M. S.; Ernst, J. A.; Gorodeisky, R.; Guttman, N.; Peimer, D. R.; Soffer, A.; Spanier, S. M.; Ritchie, J. L.; Ruland, A. M.; Schwitters, R. F.; Wray, B. C.; Izen, J. M.; Lou, X. C.; Bianchi, F.; De Mori, F.; Filippi, A.; Gamba, D.; Zambito, S.; Lanceri, L.; Vitale, L.; Martinez-Vidal, F.; Oyanguren, A.; Villanueva-Perez, P.; Albert, J.; Banerjee, Sw.; Bernlochner, F. U.; Choi, H. H. F.; King, G. J.; Kowalewski, R.; Lewczuk, M. J.; Lueck, T.; Nugent, I. M.; Roney, J. M.; Sobie, R. J.; Tasneem, N.; Gershon, T. J.; Harrison, P. F.; Latham, T. E.; Band, H. R.; Dasu, S.; Pan, Y.; Prepost, R.; Wu, S. L.; BaBar Collaboration

2014-05-01

388

Measurement of partial widths and search for direct CP violation in D0 meson decays to K-K+ and pi-pi+.  

PubMed

We present a measurement of relative partial widths and decay rate CP asymmetries in K-K+ and pi(-)pi(+) decays of D0 mesons produced in pp collisions at sqrt[s]=1.96 TeV. We use a sample of 2x10(5) D(*+)-->D0pi(+) (and charge conjugate) decays with the D0 decaying to K-pi(+), K-K+, and pi(-)pi(+), corresponding to 123 pb(-1) of data collected by the Collider Detector at Fermilab II experiment at the Fermilab Tevatron collider. No significant direct CP violation is observed. We measure Gamma(D0-->K-K+)/Gamma(D0-->K-pi(+))=0.0992+/-0.0011+/-0.0012, Gamma(D0-->pi(-)pi(+))/Gamma(D0-->K-pi(+))=0.035 94+/-0.000 54+/-0.000 40, A(CP)(K-K+)=(2.0+/-1.2+/-0.6)%, and A(CP)(pi(-)pi(+))=(1.0+/-1.3+/-0.6)%, where, in all cases, the first uncertainty is statistical and the second is systematic. PMID:15903906

Acosta, D; Affolder, T; Akimoto, T; Albrow, M G; Ambrose, D; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arisawa, T; Arguin, J-F; Artikov, A; Ashmanskas, W; Attal, A; Azfar, F; Azzi-Bacchetta, P; Bacchetta, N; Bachacou, H; Badgett, W; Barbaro-Galtieri, A; Barker, G J; Barnes, V E; Barnett, B A; Baroiant, S; Barone, M; Bauer, G; Bedeschi, F; Behari, S; Belforte, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Binkley, M; Bisello, D; Bishai, M; Blair, R E; Blocker, C; Bloom, K; Blumenfeld, B; Bocci, A; Bodek, A; Bolla, G; Bolshov, A; Booth, P S L; Bortoletto, D; Boudreau, J; Bourov, S; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Byrum, K L; Cabrera, S; Calafiura, P; Campanelli, M; Campbell, M; Canepa, A; Casarsa, M; Carlsmith, D; Carron, S; Carosi, R; Cavalli-Sforza, M; Castro, A; Catastini, P; Cauz, D; Cerri, A; Cerri, C; Cerrito, L; Chapman, J; Chen, C; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chu, M L; Chuang, S; Chung, J Y; Chung, W-H; Chung, Y S; Ciobanu, C I; Ciocci, M A; Clark, A G; Clark, D; Coca, M; Connolly, A; Convery, M; Conway, J; Cooper, B; Cordelli, M; Cortiana, G; Cranshaw, J; Cuevas, J; Culbertson, R; Currat, C; Cyr, D; Dagenhart, D; Da Ronco, S; D'Auria, S; de Barbaro, P; De Cecco, S; De Lentdecker, G; Dell'agnello, S; Dell'orso, M; Demers, S; Demortier, L; Deninno, M; De Pedis, D; Derwent, P F; Dionisi, C; Dittmann, J R; Doksus, P; Dominguez, A; Donati, S; Donega, M; Donini, J; D'Onofrio, M; Dorigo, T; Drollinger, V; Ebina, K; Eddy, N; Ely, R; Erbacher, R; Erdmann, M; Errede, D; Errede, S; Eusebi, R; Fang, H-C; Farrington, S; Fedorko, I; Feild, R G; Feindt, M; Fernandez, J P; Ferretti, C; Field, R D; Fiori, I; Flanagan, G; Flaugher, B; Flores-Castillo, L R; Foland, A; Forrester, S; Foster, G W; Franklin, M; Freeman, J; Frisch, H; Fujii, Y; Furic, I; Gajjar, A; Gallas, A; Galyardt, J; Gallinaro, M; Garcia-Sciveres, M; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D W; Gerchtein, E; Giagu, S; Giannetti, P; Gibson, A; Gibson, K; Ginsburg, C; Giolo, K; Giordani, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, D; Goldstein, J; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Gotra, Y; Goulianos, K; Gresele, A; Griffiths, M; Grosso-Pilcher, C; Guenther, M; Guimaraes da Costa, J; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Handler, R; Happacher, F; Hara, K; Hare, M; Harr, R F; Harris, R M; Hartmann, F; Hatakeyama, K; Hauser, J; Hays, C; Hayward, H; Heider, E; Heinemann, B; Heinrich, J; Hennecke, M; Herndon, M; Hill, C; Hirschbuehl, D; Hocker, A; Hoffman, K D; Holloway, A; Hou, S; Houlden, M A; Huffman, B T; Huang, Y; Hughes, R E; Huston, J; Ikado, K; Incandela, J; Introzzi, G; Iori, M; Ishizawa, Y; Issever, C; Ivanov, A; Iwata, Y; Iyutin, B; James, E; Jang, D; Jarrell, J; Jeans, D; Jensen, H; Jeon, E J; Jones, M; Joo, K K; Jun, S; Junk, T; Kamon, T; Kang, J; Karagoz Unel, M; Karchin, P E; Kartal, S; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, M S; Kim, S B; Kim, S H; Kim, T H; Kim, Y K; King, B T; Kirby, M; Kirsch, L; Klimenko, S; Knuteson, B; Ko, B R; Kobayashi, H; Koehn, P; Kong, D J; Kondo, K; Konigsberg, J; Kordas, K; Korn, A; Korytov, A; Kotelnikov, K; Kotwal, A V; Kovalev, A; Kraus, J; Kravchenko, I; Kreymer, A; Kroll, J; Kruse, M; Krutelyov, V; Kuhlmann, S E; Kuznetsova, N; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, J; Lancaster, M; Lander, R; Lannon, K; Lath, A; Latino, G; Lauhakangas, R; Lazzizzera, I; Le, Y; Lecci, C; Lecompte, T; Lee, J; Lee, J; Lee, S W; Leonardo, N; Leone, S; Lewis, J D; Li, K; Lin, C; Lin, C S; Lindgren, M; Liss, T M; Litvintsev, D O; Liu, T; Liu, Y; Lockyer, N S; Loginov, A; Loreti, M; Loverre, P; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lyons, L; Lys, J; Lysak, R; Macqueen, D; Madrak, R; Maeshima, K; Maksimovic, P; Malferrari, L; Manca, G; Marginean, R; Martin, M; Martin, A; Martin, V; Martínez, M; Maruyama, T; Matsunaga, H; Mattson, M; Mazzanti, P; McFarland, K S; McGivern, D; McIntyre, P M; McNamara, P; Ncnulty, R; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miller, L; Miller, R; Miller, J S; Miquel, R; Miscetti, S; Mitselmakher, G; Miyamoto, A; Miyazaki, Y; Moggi, N; Mohr, B; Moore, R; Morello, M; Mukherjee, A; Mulhearn, M; Muller, T; Mumford, R; Munar, A; Murat, P; Nachtman, J; Nahn, S; Nakamura, I; Nakano, I; Napier, A; Napora, R; Naumov, D; Necula, V; Niell, F; Nielsen, J; Nelson, C; Nelson, T; Neu, C; Neubauer, M S; Newman-Holmes, C; Nicollerat, A-S; Nigmanov, T; Nodulman, L; Norniella, O; Oesterberg, K; Ogawa, T; Oh, S H; Oh, Y D; Ohsugi, T; Okusawa, T; Oldeman, R; Orava, R; Orejudos, W; Pagliarone, C

2005-04-01

389

A new graph triconnectivity algorithm and its parallelization  

Microsoft Academic Search

We present a new algorithm for finding the triconnected components of an undirected graph. The algorithm is based on a method of searching graphs called ‘open ear decomposition’. A parallel implementation of the algorithm on a CRCW PRAM runs inO(log2n) parallel time usingO(n+m) processors, wheren is the number of vertices andm is the number of edges in the graph.

Gary L. Miller; Vijaya Ramachandran

1992-01-01

390

Parafrase restructuring of FORTRAN code for parallel processing  

NASA Technical Reports Server (NTRS)

Parafrase transforms a FORTRAN code, subroutine by subroutine, into a parallel code for a vector and/or shared-memory multiprocessor system. Parafrase is not a compiler; it transforms a code and provides information for a vector or concurrent process. Parafrase uses a data dependency to reveal parallelism among instructions. The data dependency test distinguishes between recurrences and statements that can be directly vectorized or parallelized. A number of transformations are required to build a data dependency graph.

Wadhwa, Atul

1988-01-01

391

Drop deformation between parallel plates  

NASA Astrophysics Data System (ADS)

Studying the nature of flow in confined geometries has become increasingly important due to downsizing of equipment. Examples include microfluidic devices as lab-on-a-chip and flow through porous media. Here, we focus on the flow of a single drop in a matrix fluid confined between two parallel walls, where the distance between the walls is in the order of the drop diameter. To model this system a three-dimensional boundary integral method is used with the inclusion of the two parallel walls in the free-space kernels of the boundary integral method. The deformation of a drop in shear flow as function of the capillary number and the distance between the walls is studied. The drop shapes found in the presence of the walls substantially differ from the typical ellipsoidal shaped drops found in unbounded flows. Overall deformation, expressed in the Taylor deformation parameter, increases when reducing the distance between the walls. Furthermore, the angle of the major drop axis with the velocity direction also decreases. A detailed analysis decribing the dynamics of breakup of drops in confined geometries is discussed.

Anderson, Patrick; Janssen, Pieter

2007-11-01

392

Dynamic search-window adjustment and interlaced search for block-matching algorithm  

Microsoft Academic Search

A technique called dynamic search-window adjustment is proposed to improve the performance of three-step searches (TSS) and to prevent the search direction from being easily misdirected by insufficient information. An interlaced-search technique is presented for the purpose of reducing the search positions. A fast search algorithm using both techniques is proposed. It is shown that the average displaced frame difference

Liang-Wei Lee; Jhing-Fa Wang; Jau-Yien Lee; Jung-Dar Shie

1993-01-01

393

Search for dayside AKR sources  

NASA Astrophysics Data System (ADS)

ABSTRACT Reports concerning observations of dayside Auroral Kilometric Radiation (AKR) sources are very scarce. This contribution presents a search of dayside AKR sources based on analysis of data collected with Polrad swept frequency analyzer during almost 2.5 years of Interball-2 mission. It is based on previous work [1], taking into account the last findings concerning AKR directivity [2]. Arguments for dayside location of some AKR sources are presented and discussed. For a given spacecraft location visibility maps of the part of auroral oval that can host sources seen from that location are constructed in the geomagnetic dipole coordinates. Maps are based on spacecraft-source rectangular coordinates system as defined in [1] and are similar to maps constructed in [2] but do not constrain values of propagation and azimuthal angles to the narrow beams detected in the frame of CLUSTER mission. If such map with maximum propagation angle 90° (no refraction) is fully located on the dayside part of the hemisphere, then AKR source in question should be located on that side too. Delimiting map to regions corresponding to the AKR beams discussed in [2], and especially taking into account beaming in the direction parallel to the auroral oval means smaller potential AKR source region that further strengthens our conclusion. On the other hand fitting lines of constant propagation angle to the lower boundary of the AKR dynamic spectrum makes possible determination of MLT of the source. References [1] Schreiber, R. (2005), A simple model of the auroral kilometric radiation visibility, J.Geophys.Res., 110, A11222, doi:10.1029/2004JA010903. [2] Mutel, R. L., I. W. Christopher, and J. S. Pickett (2008), Cluster multispacecraft determination of AKR angular beaming, Geophys.Res.Lett., 35, L07104, doi:10.1029/2008GL033377.

Schreiber, R.

2008-09-01

394

Parallel Consensual Neural Networks  

NASA Technical Reports Server (NTRS)

A new neural network architecture is proposed and applied in classification of remote sensing/geographic data from multiple sources. The new architecture is called the parallel consensual neural network and its relation to hierarchical and ensemble neural networks is discussed. The parallel consensual neural network architecture is based on statistical consensus theory. The input data are transformed several times and the different transformed data are applied as if they were independent inputs and are classified using stage neural networks. Finally, the outputs from the stage networks are then weighted and combined to make a decision. Experimental results based on remote sensing data and geographic data are given. The performance of the consensual neural network architecture is compared to that of a two-layer (one hidden layer) conjugate-gradient backpropagation neural network. The results with the proposed neural network architecture compare favorably in terms of classification accuracy to the backpropagation method.

Benediktsson, J. A.; Sveinsson, J. R.; Ersoy, O. K.; Swain, P. H.

1993-01-01

395

Parallel Subconvolution Filtering Architectures  

NASA Technical Reports Server (NTRS)

These architectures are based on methods of vector processing and the discrete-Fourier-transform/inverse-discrete- Fourier-transform (DFT-IDFT) overlap-and-save method, combined with time-block separation of digital filters into frequency-domain subfilters implemented by use of sub-convolutions. The parallel-processing method implemented in these architectures enables the use of relatively small DFT-IDFT pairs, while filter tap lengths are theoretically unlimited. The size of a DFT-IDFT pair is determined by the desired reduction in processing rate, rather than on the order of the filter that one seeks to implement. The emphasis in this report is on those aspects of the underlying theory and design rules that promote computational efficiency, parallel processing at reduced data rates, and simplification of the designs of very-large-scale integrated (VLSI) circuits needed to implement high-order filters and correlators.

Gray, Andrew A.

2003-01-01

396

The massively parallel processor  

NASA Technical Reports Server (NTRS)

Future sensor systems will utilize massively parallel computing systems for rapid analysis of two-dimensional data. The Goddard Space Flight Center has an ongoing program to develop these systems. A single-instruction multiple data computer known as the Massively Parallel Processor (MPP) is being fabricated for NASA by the Goodyear Aerospace Corporation. This processor contains 16,384 processing elements arranged in a 128 x 128 array. The MPP will be capable of adding more than 6 billion 8-bit numbers per second. Multiplication of eight-bit numbers can occur at a rate of 2 billion per second. Delivery of the MPP to Goddard Space Flight Center is scheduled for 1983.

Schaefer, D. H.; Fischer, J. R.; Wallgren, K. R.

1980-01-01

397

Collisionless parallel shocks  

NASA Technical Reports Server (NTRS)

Consideration is given to a collisionless parallel shock based on solitary-type solutions of the modified derivative nonlinear Schroedinger equation (MDNLS) for parallel Alfven waves. The standard derivative nonlinear Schroedinger equation is generalized in order to include the possible anisotropy of the plasma distribution and higher-order Korteweg-de Vies-type dispersion. Stationary solutions of MDNLS are discussed. The anisotropic nature of 'adiabatic' reflections leads to the asymmetric particle distribution in the upstream as well as in the downstream regions of the shock. As a result, nonzero heat flux appears near the front of the shock. It is shown that this causes the stochastic behavior of the nonlinear waves, which can significantly contribute to the shock thermalization.

Khabibrakhmanov, I. KH.; Galeev, A. A.; Galinskii, V. L.

1993-01-01

398

PCLIPS: Parallel CLIPS  

NASA Technical Reports Server (NTRS)

PCLIPS (Parallel CLIPS) is a set of extensions to the C Language Integrated Production System (CLIPS) expert system language. PCLIPS is intended to provide an environment for the development of more complex, extensive expert systems. Multiple CLIPS expert systems are now capable of running simultaneously on separate processors, or separate machines, thus dramatically increasing the scope of solvable tasks within the expert systems. As a tool for parallel processing, PCLIPS allows for an expert system to add to its fact-base information generated by other expert systems, thus allowing systems to assist each other in solving a complex problem. This allows individual expert systems to be more compact and efficient, and thus run faster or on smaller machines.

Gryphon, Coranth D.; Miller, Mark D.

1991-01-01

399

Fast parallel sorting algorithms  

Microsoft Academic Search

A parallel bucket-sort algorithm is presented that requires time O(log n) and the use of n processors. The algorithm makes use of a technique that requires more space than the product of processors and time. A realistic model is used in which no memory contention is permitted. A procedure is also presented to sort n numbers in time O(k log

Daniel S. Hirschberg; R. L. Rivest

1978-01-01

400

Parallel processing and simulation  

SciTech Connect

Summary form only given. High instruction execution rates may be achieved through a vorpal of inexpensive processors operating in parallel. The harnessing of this raw computing power to discrete event simulation applications is an active area of research. Three major approaches to the problem, of assigning computational tasks to processing elements may be identified: (1) model based assignment, (2) local function based assignment, and (3) global function based assignment.

Comfort, J.C.

1983-01-01

401

Cid: A Parallel, \\  

Microsoft Academic Search

Cid is a parallel, “shared-memory” superset of C for distributed-memory machines. A major objective is to keep the entry cost low. For users-the language should be easily comprehensible to a C programmer. For implementors-it should run on standard hardware (including workstation farms); it should not require major new compilation techniques (which may not even be widely applicable); and it should

Rishiyur S. Nikhil

1994-01-01

402

Parallelizing the Data Cube  

Microsoft Academic Search

Abstract. This paper presents a general methodology,for the efficient parallelization of existing data cube construction algorithms. We describe two different partitioning strategies, one for top-down and one for bottom- up cube algorithms. Both partitioning strategies assign subcubes to individual processors in such a way that the loads assigned to the processors are balanced. Our methods reduce inter processor communication,overhead by

Frank K. H. A. Dehne; Todd Eavis; Susanne E. Hambrusch; Andrew Rau-chaplin

2002-01-01

403

Device for balancing parallel strings  

DOEpatents

A battery plant is described which features magnetic circuit means in association with each of the battery strings in the battery plant for balancing the electrical current flow through the battery strings by equalizing the voltage across each of the battery strings. Each of the magnetic circuit means generally comprises means for sensing the electrical current flow through one of the battery strings, and a saturable reactor having a main winding connected electrically in series with the battery string, a bias winding connected to a source of alternating current and a control winding connected to a variable source of direct current controlled by the sensing means. Each of the battery strings is formed by a plurality of batteries connected electrically in series, and these battery strings are connected electrically in parallel across common bus conductors.

Mashikian, Matthew S. (Storrs, CT) [Storrs, CT

1985-01-01

404

Program-based static allocation policies for highly parallel computers  

Microsoft Academic Search

Static space sharing is a promising processor allocation strategy for highly-parallel computers. Parallel jobs or tasks are allocated fixed distinct subsets of processors. Thread scheduling can be carried out directly by the applications so as to reduce its cost, interference among jobs is reduced, and a wide range of compiler and runtime optimizations, including static data distribution and binding, are

Ismail M. Ismail; James A. Davis

1995-01-01

405

On the Parallelization of Radio Network Planning Tools  

Microsoft Academic Search

This paper presents a useful scheme to implement parallelization in 3G network planning tools. We propose a solution to the problem of interactions between the mobiles and the base stations, especially because of interference and macro- diversity in 3G systems that make direct parallelization unfeasible. The proposed solution decomposes the network into a grid of zones, and sequentially allocates independent

Salah-eddine Elayoubi; Benoît Fourestié; Patricia Layec

2007-01-01

406

Scattering from parallel metallic cylinders with arbitrary cross sections  

Microsoft Academic Search

The integral equations for scattering by a set of parallel metallic cylinders, each cylinder of arbitrary cross section, are solved directly by means of a digital computer program giving the current distribution induced on the scatterer surfaces, the scattering cross section vs azimuthal angle, and the induced field ratio (IFR) for both parallel and perpendicularly polarized incident waves. The present

MOGENS G. ANDREASEN

1964-01-01

407

Breakdown of Spatial Parallel Coding in Children's Drawing  

ERIC Educational Resources Information Center

When drawing real scenes or copying simple geometric figures young children are highly sensitive to parallel cues and use them effectively. However, this sensitivity can break down in surprisingly simple tasks such as copying a single line where robust directional errors occur despite the presence of parallel cues. Before we can conclude that this…

De Bruyn, Bart; Davis, Alyson

2005-01-01

408

Search Standard  

NSDL National Science Digital Library

Sherlock, first described in the October 16, 1998 Scout Report, is the new search tool provided by Mac OS 8.5 which allows users to perform searches of Websites without opening a browser. One of the great advantages of Sherlock is its ability to create a plug-in for any Web-based search engine. Since the release, the collection of Sherlock plug-ins has grown to number over 250. A few sites have taken up the task of collecting and organizing these plug-ins. While the Apple-Donuts site is a bit more polished than the others, all three of these sites provide fairly complete listings of the available plug-ins.

1999-01-01

409

Integrated Task And Data Parallel Programming: Language Design  

NASA Technical Reports Server (NTRS)

his research investigates the combination of task and data parallel language constructs within a single programming language. There are an number of applications that exhibit properties which would be well served by such an integrated language. Examples include global climate models, aircraft design problems, and multidisciplinary design optimization problems. Our approach incorporates data parallel language constructs into an existing, object oriented, task parallel language. The language will support creation and manipulation of parallel classes and objects of both types (task parallel and data parallel). Ultimately, the language will allow data parallel and task parallel classes to be used either as building blocks or managers of parallel objects of either type, thus allowing the development of single and multi-paradigm parallel applications. 1995 Research Accomplishments In February I presented a paper at Frontiers '95 describing the design of the data parallel language subset. During the spring I wrote and defended my dissertation proposal. Since that time I have developed a runtime model for the language subset. I have begun implementing the model and hand-coding simple examples which demonstrate the language subset. I have identified an astrophysical fluid flow application which will validate the data parallel language subset. 1996 Research Agenda Milestones for the coming year include implementing a significant portion of the data parallel language subset over the Legion system. Using simple hand-coded methods, I plan to demonstrate (1) concurrent task and data parallel objects and (2) task parallel objects managing both task and data parallel objects. My next steps will focus on constructing a compiler and implementing the fluid flow application with the language. Concurrently, I will conduct a search for a real-world application exhibiting both task and data parallelism within the same program m. Additional 1995 Activities During the fall I collaborated with Andrew Grimshaw and Adam Ferrari to write a book chapter which will be included in Parallel Processing in C++ edited by Gregory Wilson. I also finished two courses, Compilers and Advanced Compilers, in 1995. These courses complete my class requirements at the University of Virginia. I have only my dissertation research and defense to complete.

Grimshaw, Andrew S.; West, Emily A.

1998-01-01

410

Scalable Parallel Matrix Multiplication on Distributed Memory Parallel Computers  

Microsoft Academic Search

Consider any known sequential algorithm for matrix multiplication over an arbitrary ring with time complexity O(N?), where 2parallelized on a distributed memory parallel computer (DMPC) in O(logN) time by using N?\\/logN processors. Such a parallel computation is cost optimal and matches the performance of PRAM. Furthermore, our parallelization on a DMPC

Keqin Li

2001-01-01

411

Park Search  

NSDL National Science Digital Library

Its never too early to begin planning your summer vacation, especially in the depths of winter; those with cabin fever can get a jump on their outdoor recreation plans at this site, provided by L.L. Bean. Users can search this database of over 1,400 state and national parks, forests, and wildlife refuges by state, region, and/or activities in which they are interested (including winter sports for all-season recreators). Search returns include contact information, an overview of the park/ forest and its highlights, photos, and a list of approved or available activities.

412

Parallelizing the spectral transform method, part 2  

NASA Astrophysics Data System (ADS)

This paper describes the parallelization and performance of the spectral method for solving the shallow water equations on the surface of a sphere using a 128-node Intel iPSC/860 hypercube. The shallow water equations form a computational kernel of more complex climate models. This work is part of a research program to develop climate models that are capable of much longer simulations at a significantly finer resolution than current models. Such models are important in understanding the effects of the increasing atmospheric concentrations of greenhouse gases, and the computational requirements are so large that massively parallel multiprocessors will be necessary to run climate models simulations in a reasonable amount of time. The spectral method involves the transformation of data between the physical, Fourier, and spectral domains. Each of these domains is two-dimensional. The spectral method performs Fourier transforms in the longitude direction followed by summation in the latitude direction to evaluate the discrete spectral transform. A simple way of parallelizing the spectral code is to decompose the physical problem domain in just the latitude direction. This allows an optimized sequential FFT algorithm to be used in the longitude direction. However, this approach limits the number of processors that can be brought to bear on the problem. Decomposing the problem over both directions allows the parallelism inherent in the problem to be exploited more effectively - the grain size is reduced and more processors can be used. Results are presented that show that decomposing over both directions does result in a more rapid solution of the problem. The importance of minimizing communication latency and overlapping communication with calculation is stressed. General methods for doing this, that may be applied to many other problems, are discussed.

Walker, D. W.; Worley, P. H.; Drake, J. B.

1991-07-01

413

Scalable Parallel Genetic Algorithms  

Microsoft Academic Search

Genetic algorithms, search algorithms based on the genetic processes observed in natural evolution, have been used to solve difficult problems in many different disciplines. When applied to very large-scale problems, genetic algorithms exhibit high computational cost and degradation of the quality of the solutions because of the increased complexity. One of the most relevant research trends in genetic algorithms is

Wilson Rivera

2001-01-01

414

The study of the phase structure of hadronic matter by searching for the deconfined quark-gluon phase transition using 2 TeV [bar p]p collisions; and by searching for critical phenomena in an exclusive study of multifragmentation using 1 GeV/nucleon heavy ion collisions. [Detect ionization of charged particles directly in Si  

SciTech Connect

An experiment to search for the production of quark[endash]gluon plasma in proton[endash]antiproton interactions is described with emphasis on 1992 results. Next, a search for critical phenomena using the EOS Time Projection Chamber is similarly described, including the results of 1992 test runs, nucleus[endash]nucleus collision simulations, and the extraction of critical indices from small percolation lattices. Analysis of results from experiments to detect the possible production of anomalous photons in the central rapidity region with transverse momentum between 5 and 50 MeV/c are discussed. Initial work on an experiment to study the high-density, high-temperature state of matter formed in collisions of heavy nuclei at relativistic energies, planned to begin in fall 1997, is related. Finally, work on a research and development project to investigate silicon avalanche diodes as time-of-flight detectors for nuclear and particle physics applications is reviewed. The principle is to detect the ionization of charged particles directly in the Si; feasibility has been demonstrated.

Scharenberg, R.P.; Hirsch, A.S.; Tincknell, M.L.

1992-09-15

415

Web as a Parallel Corpus.  

National Technical Information Service (NTIS)

Parallel corpora have become an essential resource for work in multi- lingual natural language processing. In this report, we describe our work using the STRAND system for mining parallel text on the World Wide Web, first reviewing the original algorithm ...

N. A. Smith P. Resnick

2002-01-01

416

The Galley Parallel File System  

NASA Technical Reports Server (NTRS)

As the I/O needs of parallel scientific applications increase, file systems for multiprocessors are being designed to provide applications with parallel access to multiple disks. Many parallel file systems present applications with a conventional Unix-like interface that allows the application to access multiple disks transparently. The interface conceals the parallelism within the file system, which increases the ease of programmability, but makes it difficult or impossible for sophisticated programmers and libraries to use knowledge about their I/O needs to exploit that parallelism. Furthermore, most current parallel file systems are optimized for a different workload than they are being asked to support. We introduce Galley, a new parallel file system that is intended to efficiently support realistic parallel workloads. We discuss Galley's file structure and application interface, as well as an application that has been implemented using that interface.

Nieuwejaar, Nils; Kotz, David

1996-01-01

417

Searching Secrets  

Microsoft Academic Search

A Fourth Amendment violation has traditionally involved a physical intrusion such as the search of a house or the seizure of a person or her papers. Today, investigators rarely need to break down doors, rummage through drawers, or invade one’s peace and repose to obtain incriminating evidence in an investigation. Instead, the government may unobtrusively intercept information from electronic files,

Nita A. Farahany

2012-01-01

418

Biomedical Search  

NSDL National Science Digital Library

Wading through the tremendous online resource that is the BioMed archive can be a bit tricky at times. This process just got much easier through the creation of the BioMedSearch feature. The goal of this work is "to make these important works available to the community in a way that is fast and easy, while still offering the advanced features demanded by power users such as portfolios, collaboration features, bibliographical citation export, alerts, and more." Their search engine contains all of the data in Pub Med/Medline, along with additional full-text documents, and a large database of theses and dissertations. Many users will find the "Clusters" section of the site most useful. Here, visitors can view "clusters" of documents grouped together thematically into topics such as clinical trials, exercises, diet and cholesterol, and medical imagining. The homepage contains a basic search engine, and visitors may also wish to use the "Search Tutorial" to gain a better understanding of how best to use the archive.

419

Project SEARCH  

ERIC Educational Resources Information Center

Project SEARCH is a cooperative program developed for and by New York education administrators and teachers to develop products and processing for humanizing education. Its aim is to reorient teacher attitudes toward the arts through workshops that develop teachers' capacities for affective aesthetic response. Teachers then are guided in efforts…

Trupia, Charles J.

1978-01-01

420

Parallel collective resonances in arrays of gold nanorods.  

PubMed

In this work we discuss the excitation of parallel collective resonances in arrays of gold nanoparticles. Parallel collective resonances result from the coupling of the nanoparticles localized surface plasmons with diffraction orders traveling in the direction parallel to the polarization vector. While they provide field enhancement and delocalization as the standard collective resonances, our results suggest that parallel resonances could exhibit greater tolerance to index asymmetry in the environment surrounding the arrays. The near- and far-field properties of these resonances are analyzed, both experimentally and numerically. PMID:24645987

Vitrey, Alan; Aigouy, Lionel; Prieto, Patricia; García-Martín, José Miguel; González, María U

2014-04-01

421

Some fast elliptic solvers on parallel architectures and their complexities  

NASA Technical Reports Server (NTRS)

The discretization of separable elliptic partial differential equations leads to linear systems with special block tridiagonal matrices. Several methods are known to solve these systems, the most general of which is the Block Cyclic Reduction (BCR) algorithm which handles equations with nonconstant coefficients. A method was recently proposed to parallelize and vectorize BCR. In this paper, the mapping of BCR on distributed memory architectures is discussed, and its complexity is compared with that of other approaches including the Alternating-Direction method. A fast parallel solver is also described, based on an explicit formula for the solution, which has parallel computational compelxity lower than that of parallel BCR.

Gallopoulos, E.; Saad, Y.

1989-01-01

422

Parallel Pascal - An extended Pascal for parallel computers  

NASA Technical Reports Server (NTRS)

Parallel Pascal is an extended version of the conventional serial Pascal programming language which includes a convenient syntax for specifying array operations. It is upward compatible with standard Pascal and involves only a small number of carefully chosen new features. Parallel Pascal was developed to reduce the semantic gap between standard Pascal and a large range of highly parallel computers. Two important design goals of Parallel Pascal were efficiency and portability. Portability is particularly difficult to achieve since different parallel computers frequently have very different capabilities.

Reeves, A. P.

1984-01-01

423

Parallel Adaptations to High Temperatures in the Archaean Eon  

NASA Astrophysics Data System (ADS)

We reconstructed in silico rRNA and protein sequences for the ancestors of living organisms, and found evidence for parallel adaptations to high temperatures between the Last Universal Common Ancestor (LUCA) and its direct descendants.

Boussau, B.; Blanquart, S.; Necsulea, A.; Lartillot, N.; Gouy, M.

2010-04-01

424

Parallel Eclipse Project Checkout  

NASA Technical Reports Server (NTRS)

Parallel Eclipse Project Checkout (PEPC) is a program written to leverage parallelism and to automate the checkout process of plug-ins created in Eclipse RCP (Rich Client Platform). Eclipse plug-ins can be aggregated in a feature project. This innovation digests a feature description (xml file) and automatically checks out all of the plug-ins listed in the feature. This resolves the issue of manually checking out each plug-in required to work on the project. To minimize the amount of time necessary to checkout the plug-ins, this program makes the plug-in checkouts parallel. After parsing the feature, a request to checkout for each plug-in in the feature has been inserted. These requests are handled by a thread pool with a configurable number of threads. By checking out the plug-ins in parallel, the checkout process is streamlined before getting started on the project. For instance, projects that took 30 minutes to checkout now take less than 5 minutes. The effect is especially clear on a Mac, which has a network monitor displaying the bandwidth use. When running the client from a developer s home, the checkout process now saturates the bandwidth in order to get all the plug-ins checked out as fast as possible. For comparison, a checkout process that ranged from 8-200 Kbps from a developer s home is now able to saturate a pipe of 1.3 Mbps, resulting in significantly faster checkouts. Eclipse IDE (integrated development environment) tries to build a project as soon as it is downloaded. As part of another optimization, this innovation programmatically tells Eclipse to stop building while checkouts are happening, which dramatically reduces lock contention and enables plug-ins to continue downloading until all of them finish. Furthermore, the software re-enables automatic building, and forces Eclipse to do a clean build once it finishes checking out all of the plug-ins. This software is fully generic and does not contain any NASA-specific code. It can be applied to any Eclipse-based repository with a similar structure. It also can apply build parameters and preferences automatically at the end of the checkout.

Crockett, Thomas M.; Joswig, Joseph C.; Shams, Khawaja S.; Powell, Mark W.; Bachmann, Andrew G.

2011-01-01

425

Fastpath Speculative Parallelization  

NASA Astrophysics Data System (ADS)

We describe Fastpath, a system for speculative parallelization of sequential programs on conventional multicore processors. Our system distinguishes between the lead thread, which executes at almost-native speed, and speculative threads, which execute somewhat slower. This allows us to achieve nontrivial speedup, even on two-core machines. We present a mathematical model of potential speedup, parameterized by application characteristics and implementation constants. We also present preliminary results gleaned from two different Fastpath implementations, each derived from an implementation of software transactional memory.

Spear, Michael F.; Kelsey, Kirk; Bai, Tongxin; Dalessandro, Luke; Scott, Michael L.; Ding, Chen; Wu, Peng

426

Synchronous Parallel Kinetic Monte Carlo  

SciTech Connect

A novel parallel kinetic Monte Carlo (kMC) algorithm formulated on the basis of perfect time synchronicity is presented. The algorithm provides an exact generalization of any standard serial kMC model and is trivially implemented in parallel architectures. We demonstrate the mathematical validity and parallel performance of the method by solving several well-understood problems in diffusion.

Mart?nez, E; Marian, J; Kalos, M H

2006-12-14

427

Parallel Computing Experiences with CUDA  

Microsoft Academic Search

The CUDA programming model provides a straightforward means of describing inherently parallel computations, and NVIDIA's Tesla GPU architecture delivers high computational throughput on massively parallel problems. This article surveys experiences gained in applying CUDA to a diverse set of problems and the parallel speedups over sequential codes running on traditional CPU architectures attained by executing key computations on the GPU.

Michael Garland; Scott Le Grand; John Nickolls; Joshua Anderson; Jim Hardwick; Scott Morton; Everett Phillips; Yao Zhang; Vasily Volkov

2008-01-01

428

Searching for New Directions for IT Financing.  

ERIC Educational Resources Information Center

Presents highlights from a conference call involving six experts on spending for higher education information technology (IT). Participants discussed solid strategies for smart purchasing, sensible financing, and discipline that allow an institution to focus on its mission in a climate of fads and quick-fix technological temptations. (EV)

Trusteeship, 2001

2001-01-01

429

Parallelization of NAS Benchmarks for Shared Memory Multiprocessors  

NASA Technical Reports Server (NTRS)

This paper presents our experiences of parallelizing the sequential implementation of NAS benchmarks using compiler directives on SGI Origin2000 distributed shared memory (DSM) system. Porting existing applications to new high performance parallel and distributed computing platforms is a challenging task. Ideally, a user develops a sequential version of the application, leaving the task of porting to new generations of high performance computing systems to parallelization tools and compilers. Due to the simplicity of programming shared-memory multiprocessors, compiler developers have provided various facilities to allow the users to exploit parallelism. Native compilers on SGI Origin2000 support multiprocessing directives to allow users to exploit loop-level parallelism in their programs. Additionally, supporting tools can accomplish this process automatically and present the results of parallelization to the users. We experimented with these compiler directives and supporting tools by parallelizing sequential implementation of NAS benchmarks. Results reported in this paper indicate that with minimal effort, the performance gain is comparable with the hand-parallelized, carefully optimized, message-passing implementations of the same benchmarks.

Waheed, Abdul; Yan, Jerry C.; Saini, Subhash (Technical Monitor)

1998-01-01

430

Tolerant (Parallel) Programming  

NASA Technical Reports Server (NTRS)

In order to be truly portable, a program must be tolerant of a wide range of development and execution environments, and a parallel program is just one which must be tolerant of a very wide range. This paper first defines the term "tolerant programming", then describes many layers of tools to accomplish it. The primary focus is on F-Nets, a formal model for expressing computation as a folded partial-ordering of operations, thereby providing an architecture-independent expression of tolerant parallel algorithms. For implementing F-Nets, Cooperative Data Sharing (CDS) is a subroutine package for implementing communication efficiently in a large number of environments (e.g. shared memory and message passing). Software Cabling (SC), a very-high-level graphical programming language for building large F-Nets, possesses many of the features normally expected from today's computer languages (e.g. data abstraction, array operations). Finally, L2(sup 3) is a CASE tool which facilitates the construction, compilation, execution, and debugging of SC programs.

DiNucci, David C.; Bailey, David H. (Technical Monitor)

1997-01-01

431

Parallel Eigenvalue extraction  

NASA Technical Reports Server (NTRS)

A new numerical algorithm for the solution of large-order eigenproblems typically encountered in linear elastic finite element systems is presented. The architecture of parallel processing is utilized in the algorithm to achieve increased speed and efficiency of calculations. The algorithm is based on the frontal technique for the solution of linear simultaneous equations and the modified subspace eigenanalysis method for the solution of the eigenproblem. Assembly, elimination and back-substitution of degrees of freedom are performed concurrently, using a number of fronts. All fronts converge to and diverge from a predefined global front during elimination and back-substitution, respectively. In the meantime, reduction of the stiffness and mass matrices required by the modified subspace method can be completed during the convergence/divergence cycle and an estimate of the required eigenpairs obtained. Successive cycles of convergence and divergence are repeated until the desired accuracy of calculations is achieved. The advantages of this new algorithm in parallel computer architecture are discussed.

Akl, Fred A.

1989-01-01

432

Making parallel lines meet  

PubMed Central

The extracellular matrix is constructed beyond the plasma membrane, challenging mechanisms for its control by the cell. In plants, the cell wall is highly ordered, with cellulose microfibrils aligned coherently over a scale spanning hundreds of cells. To a considerable extent, deploying aligned microfibrils determines mechanical properties of the cell wall, including strength and compliance. Cellulose microfibrils have long been seen to be aligned in parallel with an array of microtubules in the cell cortex. How do these cortical microtubules affect the cellulose synthase complex? This question has stood for as many years as the parallelism between the elements has been observed, but now an answer is emerging. Here, we review recent work establishing that the link between microtubules and microfibrils is mediated by a protein named cellulose synthase-interacting protein 1 (CSI1). The protein binds both microtubules and components of the cellulose synthase complex. In the absence of CSI1, microfibrils are synthesized but their alignment becomes uncoupled from the microtubules, an effect that is phenocopied in the wild type by depolymerizing the microtubules. The characterization of CSI1 significantly enhances knowledge of how cellulose is aligned, a process that serves as a paradigmatic example of how cells dictate the construction of their extracellular environment.