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1

Multi-directional search: A direct search algorithm for parallel machines

In recent years there has been a great deal in the development of optimization algorithms which exploit the computational power of parallel computer architectures. The author has developed a new direct search algorithm, which he calls multi-directional search, that is ideally suited for parallel computation. His algorithm belongs to the class of direct search methods, a class of optimization algorithms

Virginia Joanne Torczon

1989-01-01

2

Experience with approximations in the trust-region parallel direct search algorithm.

Recent years have seen growth in the number of algorithms designed to solve challenging simulation-based nonlinear optimization problems. One such algorithm is the Trust-Region Parallel Direct Search (TRPDS) method developed by Hough and Meza. In this paper, we take advantage of the theoretical properties of TRPDS to make use of approximation models in order to reduce the computational cost of simulation-based optimization. We describe the extension, which we call mTRPDS, and present the results of a case study for two earth penetrator design problems. In the case study, we conduct computational experiments with an array of approximations within the mTRPDS algorithm and compare the numerical results to the original TRPDS algorithm and a trust-region method implemented using the speculative gradient approach described by Byrd, Schnabel, and Shultz. The results suggest new ways to improve the algorithm.

Shontz, Suzanne M. (Pennsylvania State University, University Park, PA); Hough, Patricia Diane; Howle, Victoria E. (Texas Tech University, Lubbock, TX)

2009-01-01

3

PDS: Direct Search Methods for Unconstrained Optimization on Either Sequential or Parallel Machines

. PDS is a collection of Fortran subroutines for solving unconstrained nonlinear optimizationproblems using direct search methods. The software is written so that execution on sequentialmachines is straightforward while execution on Intel distributed memory machines, such as the iPSC\\/2,the iPSC\\/860 or the Touchstone Delta, can be accomplished simply by including a few well-definedroutines containing calls to Intel-specific Fortran libraries. Those

Virginia Torczon

1992-01-01

4

Parallel Search On Video Cards

Recent approaches exploiting the massively parallel ar- chitecture of graphics processors (GPUs) to acceler- ate database operations have achieved intriguing results. While parallel sorting received significant attention, par- allel search has not been explored. With p-ary search we present a novel parallel search algorithm for large-scale database index operations that scales with the number of processors and outperforms traditional thread-level

Tim Kaldewey; Jeff Hagen; Eric Sedlar

5

A parallel string search algorithm

A new parallel processing algorithm for solving string search problems is presented. The proposed algorithm uses O(m×n) processors where n is the length of a text and m is the length of a pattern. It requires two and only two iteration steps to find the pattern in the text, while the best existing parallel algorithm needs the computation time O(loglog

Yoshiyasu Takefuji; Toshimitsu Tanaka; Kuo Chun Lee

1992-01-01

6

Parallel Processing in Visual Search Asymmetry

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 time courses of the 2 tasks were similar and

Barbara Anne Dosher; Songmei Han; Zhong-Lin Lu

2004-01-01

7

Asynchronous parallel hybrid optimization combining DIRECT and GSS

In this paper, we explore hybrid parallel global optimization using Dividing Rectangles (DIRECT) and asynchronous generating set search (GSS). Both DIRECT and GSS are derivative-free and so require only objective function values; this makes these methods applicable to a wide variety of science and engineering problems. DIRECT is a global search method that strategically divides the search space into ever-smaller

Joshua D. Griffin; Tamara G. Kolda

2010-01-01

8

Parallel Search Algorithms for Robot Motion Planning

In this paper we show that parallel search techniques derived from their sequential counterparts can enable the solution of instances of the robot motion planning problem that are computationally infeasible on sequential machines. We present a simple parallel version of a robot motion planning algorithm based on \\

Daniel J. Challou; Maria L. Gini; Vipin Kumar

1993-01-01

9

Parallel search of strongly ordered game trees

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

10

Parallel Depth First Search on Distributed Memory Multiprocessors.

National Technical Information Service (NTIS)

Iterative deepening A* (IDA*) technique is well-known for its superior performance among various search techniques in the depth-first search family. In the report, the authors parallelize the IDA* search on distributed memory multiprocessors. Performing s...

R. K. Joshi P. S. Kumar A. Basu

1992-01-01

11

Asynchronous parallel hybrid optimization combining DIRECT and GSS

In this talk, we explore the benefits of hybrid optimization using parallel versions of DIRECT and asynchronous generating set search (GSS) for optimization. Both of these methods are derivative-free, making them useful for a variety of science and engineering problems. Our goal is to ideally find a global minimum, but practically to find a good local minimum in a small

Joshua D. Griffin; Tamara Gibson Kolda

2008-01-01

12

Parallel analog neural networks for tree searching

NASA Astrophysics Data System (ADS)

We have modeled parallel analog neural networks designed such that their evolution toward final states is equivalent to finding optimal (or nearly optimal) paths through decision trees. This work extends that done on the Traveling Salesman Problem (TSP)[1] and sheds light on the conditions under which analog neural networks can and cannot find solutions to discrete optimization problems. Neural networks show considerable specificity in finding optimal solutions for tree searches; in the cases when a final state does represent a syntactically correct path, that path will be the best path 70-90% of the time-even for trees with up to two thousand nodes. However, it appears that except for trivial networks lacking the ability to ``think globally,'' there exists no general network architecture that can strictly insure the convergence a state that represents a single, continuous, unambiguous path. In fact, we find that for roughly 15% of trees with six generations, 40% of trees with eight generations, and 70% of trees with ten generations, networks evolve to ``broken paths,'' i.e., combinations of the beginning of one and the end of another path through a tree. Tree searches illustrate well neural dynamics because tree structures make the effects of competition and positive feedback apparent. We have found that 1) convergence times for networks with up to 2000 neurons are very rapid, depend on the gain of neurons and magnitude of neural connections but not on the number of generations or branching factor of a tree, 2) all neurons along a ``winning'' path turn on exponentially with the same exponent, and 3) the general computational mechanism of these networks appears to be the pruning of a tree from the outer branches inward, as chain reactions of neurons being quenched tend to propagate along possible paths.

Saylor, Janet; Stork, David G.

1986-08-01

13

Managing parallel inquiries in agents' two-sided search

In this paper we address the problem of agents engaged in a distributed costly two-sided search for pairwise partnerships in Multi-Agent Systems (MAS). While traditional two-sided search mechanisms are based on a purely sequential search of all searchers, our mechanism integrates an ability of some of the agents to maintain several search efforts in parallel at each search stage. We

David Sarne; Sarit Kraus

2008-01-01

14

Sequential decision making in parallel two-sided economic search

This paper presents a two-sided economic search model in which agents are searching for beneficial pairwise partnerships. In each search stage, each of the agents is randomly matched with several other agents in parallel, and makes a decision whether to accept a potential partnership with one of them. The distinguishing feature of the proposed model is that the agents are

David Sarne; Teijo Arponen

2007-01-01

15

Dark matter is hypothetical matter which does not interact with electromagnetic radiation. The existence of dark matter is only inferred from gravitational effects of astrophysical observations to explain the missing mass component of the Universe. Weakly Interacting Massive Particles are currently the most popular candidate to explain the missing mass component. I review the current status of experimental searches of dark matter through direct detection using terrestrial detectors.

Yoo, Jonghee; /Fermilab

2009-12-01

16

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

17

Parallel and Serial Processes in Visual Search

ERIC Educational Resources Information Center

|A long-standing issue in the study of how people acquire visual information centers around the scheduling and deployment of attentional resources: Is the process serial, or is it parallel? A substantial empirical effort has been dedicated to resolving this issue. However, the results remain largely inconclusive because the methodologies that have…

Thornton, Thomas L.; Gilden, David L.

2007-01-01

18

ERIC Educational Resources Information Center

|Discusses the results of modeling the performance of searching large text databases via various parallel hardware architectures and search algorithms. The performance under load and the cost of each configuration are compared, and a common search workload used in the modeling is described. (Contains 26 references.) (LRW)|

Couvreur, T. R.; And Others

1994-01-01

19

MAX search with parallel verification for frame synchronization

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

20

Solving the Flow Shop Problem by Parallel Tabu Search

In this paper we present parallel tabu search algo- rithm for the permutation flow shop sequencing prob- lem with the objective of minimizing the flowtime. We propose a neighbourhood using so-called blocks of jobs on a critical path and a backtrace jump method. By computer simulations it is shown that the performance of the proposed algorithm is comparable with the

Wojciech Bozejko; Mieczyslaw Wodecki

2002-01-01

21

PLAST: parallel local alignment search tool for database comparison

Background Sequence similarity searching is an important and challenging task in molecular biology and next-generation sequencing should further strengthen the need for faster algorithms to process such vast amounts of data. At the same time, the internal architecture of current microprocessors is tending towards more parallelism, leading to the use of chips with two, four and more cores integrated on the same die. The main purpose of this work was to design an effective algorithm to fit with the parallel capabilities of modern microprocessors. Results A parallel algorithm for comparing large genomic banks and targeting middle-range computers has been developed and implemented in PLAST software. The algorithm exploits two key parallel features of existing and future microprocessors: the SIMD programming model (SSE instruction set) and the multithreading concept (multicore). Compared to multithreaded BLAST software, tests performed on an 8-processor server have shown speedup ranging from 3 to 6 with a similar level of accuracy. Conclusion A parallel algorithmic approach driven by the knowledge of the internal microprocessor architecture allows significant speedup to be obtained while preserving standard sensitivity for similarity search problems.

Nguyen, Van Hoa; Lavenier, Dominique

2009-01-01

22

Parallel Breadth-First Search on Distributed Memory Systems

Data-intensive, graph-based computations are pervasive in several scientific applications, and are known to to be quite challenging to implement on distributed memory systems. In this work, we explore the design space of parallel algorithms for Breadth-First Search (BFS), a key subroutine in several graph algorithms. We present two highly-tuned par- allel approaches for BFS on large parallel systems: a level-synchronous strategy that relies on a simple vertex-based partitioning of the graph, and a two-dimensional sparse matrix- partitioning-based approach that mitigates parallel commu- nication overhead. For both approaches, we also present hybrid versions with intra-node multithreading. Our novel hybrid two-dimensional algorithm reduces communication times by up to a factor of 3.5, relative to a common vertex based approach. Our experimental study identifies execu- tion regimes in which these approaches will be competitive, and we demonstrate extremely high performance on lead- ing distributed-memory parallel systems. For instance, for a 40,000-core parallel execution on Hopper, an AMD Magny- Cours based system, we achieve a BFS performance rate of 17.8 billion edge visits per second on an undirected graph of 4.3 billion vertices and 68.7 billion edges with skewed degree distribution.

Computational Research Division; Buluc, Aydin; Madduri, Kamesh

2011-04-15

23

Parallel Distractor Rejection as a Binding Mechanism in Search

The relatively common experimental visual search task of finding a red X amongst red O’s and green X’s (conjunction search) presents the visual system with a binding problem. Illusory conjunctions (ICs) of features across objects must be avoided and only features present in the same object bound together. Correct binding into unique objects by the visual system may be promoted, and ICs minimized, by inhibiting the locations of distractors possessing non-target features (e.g., Treisman and Sato, 1990). Such parallel rejection of interfering distractors leaves the target as the only item competing for selection; thus solving the binding problem. In the present article we explore the theoretical and empirical basis of this process of active distractor inhibition in search. Specific experiments that provide strong evidence for a process of active distractor inhibition in search are highlighted. In the final part of the article we consider how distractor inhibition, as defined here, may be realized at a neurophysiological level (Treisman and Sato, 1990).

Dent, Kevin; Allen, Harriet A.; Braithwaite, Jason J.; Humphreys, Glyn W.

2012-01-01

24

Information-Limited Parallel Processing in Difficult Heterogeneous Covert Visual Search

ERIC Educational Resources Information Center

|Difficult visual search is often attributed to time-limited serial attention operations, although neural computations in the early visual system are parallel. Using probabilistic search models (Dosher, Han, & Lu, 2004) and a full time-course analysis of the dynamics of covert visual search, we distinguish unlimited capacity parallel versus serial…

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

2010-01-01

25

Exploiting Parallelism to Accelerate Keyword Search on Deep-Web Sources

Increasingly, biological data is being shared over the deep web. Many biological queries can only be answered by successively search- ing a number of distinct web-sites. This paper introduces a system that exploits parallelization for accelerating search over multiple deep web data sources. An interactive, two-stage multi-threading system is devel- oped to achieve task parallelization, thread parallelization, and pipelined parallelization.

Tantan Liu; Fan Wang; Gagan Agrawal

2009-01-01

26

Highly Parallel Alternating Directions Algorithm for Time Dependent Problems

NASA Astrophysics Data System (ADS)

In our work, we consider the time dependent Stokes equation on a finite time interval and on a uniform rectangular mesh, written in terms of velocity and pressure. For this problem, a parallel algorithm based on a novel direction splitting approach is developed. Here, the pressure equation is derived from a perturbed form of the continuity equation, in which the incompressibility constraint is penalized in a negative norm induced by the direction splitting. The scheme used in the algorithm is composed of two parts: (i) velocity prediction, and (ii) pressure correction. This is a Crank-Nicolson-type two-stage time integration scheme for two and three dimensional parabolic problems in which the second-order derivative, with respect to each space variable, is treated implicitly while the other variable is made explicit at each time sub-step. In order to achieve a good parallel performance the solution of the Poison problem for the pressure correction is replaced by solving a sequence of one-dimensional second order elliptic boundary value problems in each spatial direction. The parallel code is implemented using the standard MPI functions and tested on two modern parallel computer systems. The performed numerical tests demonstrate good level of parallel efficiency and scalability of the studied direction-splitting-based algorithm.

Ganzha, M.; Georgiev, K.; Lirkov, I.; Margenov, S.; Paprzycki, M.

2011-11-01

27

Agents' Strategies for the Dual Parallel Search in Partnership Formation Applications

In many two-sided search applications, autonomous agents can enjoy the advantage of parallel search, powered by their ability to handle an enormous amount of information, in a short time, and the capability to maintain interaction with several other agents in parallel. The adoption of the new technique by an agent suggests a reduction in the average cost per interaction with

David Sarne; Sarit Kraus

2004-01-01

28

An Architecture for Parallel Search of Large, Full-Text Databases

A novel signature approach is introduced for retrieval of documents from large text databases. The structure of the signature files under this approach lends itself to a highly parallel hardware implementation. The signature files are generated by software and loaded into RAM. Upon a user query, the signature files are searched in parallel by a special-purpose search module for identification

Nassrin Tavakoli; Hassan Modaress-razavi

1990-01-01

29

Implementation of parallel search algorithms using spatial encoding by nuclear magnetic resonance

NASA Astrophysics Data System (ADS)

Information storage and database search are attractive areas in the field of nuclear magnetic resonance. Among the notable works reported earlier, an implementation of a parallel search algorithm in a dipolar coupled spin cluster has gained considerable attention [A. Khitrin, V. L. Ermakov, and B. M. Fung, Phys. Rev. Lett. 89, 277902 (2002)]. In this paper, we propose and exemplify that spatial encoding can be successfully utilized in realizing such parallel algorithms. We also introduce an improved protocol of the parallel search algorithm, which can be realized using spatial encoding. The methods have been demonstrated to perform a search operation using 215 bits.

Bhattacharyya, Rangeet; Das, Ranabir; Ramanathan, K. V.; Kumar, Anil

2005-05-01

30

Nonlinearly-constrained optimization using asynchronous parallel generating set search.

Many optimization problems in computational science and engineering (CS&E) are characterized by expensive objective and/or constraint function evaluations paired with a lack of derivative information. Direct search methods such as generating set search (GSS) are well understood and efficient for derivative-free optimization of unconstrained and linearly-constrained problems. This paper addresses the more difficult problem of general nonlinear programming where derivatives for objective or constraint functions are unavailable, which is the case for many CS&E applications. We focus on penalty methods that use GSS to solve the linearly-constrained problems, comparing different penalty functions. A classical choice for penalizing constraint violations is {ell}{sub 2}{sup 2}, the squared {ell}{sub 2} norm, which has advantages for derivative-based optimization methods. In our numerical tests, however, we show that exact penalty functions based on the {ell}{sub 1}, {ell}{sub 2}, and {ell}{sub {infinity}} norms converge to good approximate solutions more quickly and thus are attractive alternatives. Unfortunately, exact penalty functions are discontinuous and consequently introduce theoretical problems that degrade the final solution accuracy, so we also consider smoothed variants. Smoothed-exact penalty functions are theoretically attractive because they retain the differentiability of the original problem. Numerically, they are a compromise between exact and {ell}{sub 2}{sup 2}, i.e., they converge to a good solution somewhat quickly without sacrificing much solution accuracy. Moreover, the smoothing is parameterized and can potentially be adjusted to balance the two considerations. Since many CS&E optimization problems are characterized by expensive function evaluations, reducing the number of function evaluations is paramount, and the results of this paper show that exact and smoothed-exact penalty functions are well-suited to this task.

Griffin, Joshua D.; Kolda, Tamara Gibson

2007-05-01

31

Coordinating Computation and I\\/O in Massively Parallel Sequence Search

With the explosive growth of genomic information, the searching of sequence databases has emerged as one of the most computation- and data-intensive scientific applications. Our previous studies suggested that parallel genomic sequence-search possesses highly irregular computation and I\\/O patterns. Effectively addressing these run-time irregularities is thus the key to designing scalable sequence-search tools on massively parallel computers. While the computation

Heshan Lin; Xiaosong Ma; Wuchun Feng; Nagiza F. Samatova

2011-01-01

32

Parallel perceptrons (PPs) are very simple and efficient committee machines (a single layer of perceptrons with threshold activation functions and binary outputs, and a majority voting decision scheme), which nevertheless behave as universal approximators. The parallel delta (P-Delta) rule is an effective training algorithm, which, following the ideas of statistical learning theory used by the support vector machine (SVM), raises its generalization ability by maximizing the difference between the perceptron activations for the training patterns and the activation threshold (which corresponds to the separating hyperplane). In this paper, we propose an analytical closed-form expression to calculate the PPs' weights for classification tasks. Our method, called Direct Parallel Perceptrons (DPPs), directly calculates (without iterations) the weights using the training patterns and their desired outputs, without any search or numeric function optimization. The calculated weights globally minimize an error function which simultaneously takes into account the training error and the classification margin. Given its analytical and noniterative nature, DPPs are computationally much more efficient than other related approaches (P-Delta and SVM), and its computational complexity is linear in the input dimensionality. Therefore, DPPs are very appealing, in terms of time complexity and memory consumption, and are very easy to use for high-dimensional classification tasks. On real benchmark datasets with two and multiple classes, DPPs are competitive with SVM and other approaches but they also allow online learning and, as opposed to most of them, have no tunable parameters. PMID:21984498

Fernandez-Delgado, Manuel; Ribeiro, Jorge; Cernadas, Eva; Ameneiro, Senén Barro

2011-10-06

33

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

34

Direct binary search (DBS) algorithm with constraints

NASA Astrophysics Data System (ADS)

In this paper, we describe adding constraints to the Direct Binary Search (DBS) algorithm. An example of a useful constraint, illustrated in this paper, is having only one dot per column and row. DBS with such constraints requires greater than two toggles during each trial operation. Implementations of the DBS algorithm traditionally limit operations to either one toggle or swap during each trial. The example case in this paper produces a wrap-around pattern with uniformly distributed ON pixels which will have a pleasing appearance with precisely one ON pixel per each column and row. The algorithm starts with an initial continuous tone image and an initial pattern having only one ON pixel per column and row. The auto correlation function of Human Visual System (HVS) model is determined along with an initial perceived error. Multiple operation pixel error processing during each iteration is used to enforce the one ON pixel per column and row constraint. The constraint of a single ON pixel per column and row is used as an example in this paper. Further modification of the DBS algorithm for other constraints is possible, based on the details given in the paper. A mathematical framework to extend the algorithm to the more general case of Direct Multi-bit Search (DMS) is presented.

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

2013-02-01

35

A new parallelization method is proposed for factored alternating direction implicit (ADI) schemes based on the vectorized global domain directional sweep. This approach, when combined with multi-partitioning domain decomposition, significantly reduces the frequency of necessary communication calls and minimizes processor idling during the sweeping processes. The present parallelization approach is applied to a number of vectorized two-dimensional compressible Navier-Stokes solvers.

Y. D. Jun; A. Hamed

1998-01-01

36

A review of direct WIMP search experiments

NASA Astrophysics Data System (ADS)

The dynamics of the Milky Way provides evidence for a non-luminous mass component. The dark matter could be made of new, color and charge neutral particles, which were non-relativistic when they decoupled from ordinary matter in the early Universe. Dark matter particles are predicted to have a non-zero coupling to baryons and could be detected via their collisions with atomic nuclei in ultra-low background, deep underground detectors. Predicted nuclear recoil energies are smaller than ˜50 keV and expected scattering rates are well below 1 event per year and kg of target material. After an introduction to the methodology, I will briefly discuss the main experimental techniques used in direct dark matter searches, with emphasis on current results and on the status of future projects.

Baudis, Laura

2013-02-01

37

Fencing direct memory access (`DMA`) data transfers in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI including data communications endpoints, each endpoint including specifications of a client, a context, and a task, the endpoints coupled for data communications through the PAMI and through DMA controllers operatively coupled to segments of shared random access memory through which the DMA controllers deliver data communications deterministically, including initiating execution through the PAMI of an ordered sequence of active DMA instructions for DMA data transfers between two endpoints, effecting deterministic DMA data transfers through a DMA controller and a segment of shared memory; and executing through the PAMI, with no FENCE accounting for DMA data transfers, an active FENCE instruction, the FENCE instruction completing execution only after completion of all DMA instructions initiated prior to execution of the FENCE instruction for DMA data transfers between the two endpoints.

Blocksome, Michael A.; Mamidala, Amith R.

2013-09-03

38

A Parallel Search for Good Lattice Points using LLL-Spectral Tests

We present results from an extensive parallel search for rank-1 lattice rules using the LLL-spectral test with a new normalization strategy which is proposed in (1). We introduce the main concepts concerning lattice rules and the spectral test and mo- tivate the new normalization strategy for this test. The concepts for parallelization are explained and some results conclude the article.

Bernhard Hechenleitner; Karl Entacher

2005-01-01

39

Scalable Global and Local Hashing Strategies for Duplicate Pruning in Parallel A* Graph Search

For many applications of the A* algorithm, the state space is a graph rather than a tree. The implication of this for parallel A* algorithms is that different processors may perform significant duplicated work if interprocessor duplicates are not pruned. In this paper, we consider the problem of duplicate pruning in parallel A* graph-search algorithms implemented on distributed-memory machines. A

Nihar R. Mahapatra; Shantanu Dutt

1997-01-01

40

Parallel algorithms and architectures for very fast AI search

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

41

Parallel assembly for multiple site-directed mutagenesis of plasmids.

A parallel assembly method for multiple site-directed mutagenesis of plasmids was developed here based on Golden Gate cloning. It takes advantage of type IIs restriction enzymes and T4 DNA ligase to assemble multiple DNA fragments into a plasmid by a defined order. This method can accommodate multiple plasmid mutagenesis at any desired position with all three sequence modification types (substitution, deletion, and insertion) simultaneously. Furthermore, it can be used to create otherwise difficult-to-make mutants-larger deletions and insertions and mutagenesis on larger plasmids. The processes of mutagenesis can be completed quickly by a single restriction-ligation reaction. PMID:22885236

Yan, Pu; Gao, XinZheng; Shen, Wentao; Zhou, Peng; Duan, Jun

2012-08-08

42

Pathfinder: A parallel search algorithm for concerted atomistic events

An algorithm has been designed to search for the escape paths with the lowest activation barriers when starting from a local minimum-energy configuration of a many-atom system. The pathfinder algorithm combines: (1) a steered eigenvector-following method that guides a constrained escape from the convex region and subsequently climbs to a transition state tangentially to the eigenvector corresponding to the lowest

Aiichiro Nakano

2007-01-01

43

Parallel implementation of a direct method for calculating electrostatic potentials.

The authors present a method for calculating the electrostatic potential directly in a straightforward manner. While traditional methods for calculating the electrostatic potential usually involve solving the Poisson equation iteratively, the authors obtain the electrostatic interaction potential by performing direct numerical integration of the Coulomb-law expression using finite-element functions defined on a grid. The singularity of the Coulomb operator is circumvented by an integral transformation and the resulting auxiliary integral is obtained using Gaussian quadrature. The three-dimensional finite-element basis is constructed as a tensor (outer) product of one-dimensional functions, yielding a partial factorization of the expressions. The resulting algorithm has, without using any prescreening or other computational tricks, a formal computational scaling of Omicron(N4/3), where N is the size of the grid. The authors show here how to implement the method for efficiently running on parallel computers. The matrix multiplications of the innermost loops are completely independent, yielding a parallel algorithm with the computational costs scaling practically linearly with the number of processors. PMID:17362098

Jusélius, Jonas; Sundholm, Dage

2007-03-01

44

Information-limited parallel processing in difficult heterogeneous covert visual search.

Difficult visual search is often attributed to time-limited serial attention operations, although neural computations in the early visual system are parallel. Using probabilistic search models (Dosher, Han, & Lu, 2004) and a full time-course analysis of the dynamics of covert visual search, we distinguish unlimited capacity parallel versus serial search mechanisms. Performance is measured for difficult and error-prone searches among heterogeneous background elements and for easy and accurate searches among homogeneous background elements. Contrary to the claims of time-limited serial attention, searches in heterogeneous backgrounds instead exhibited nearly identical search dynamics for display sizes up to 12 items. A review and new analyses indicate that most difficult as well as easy visual searches operate as an unlimited-capacity parallel analysis over the visual field within a single eye fixation, which suggests limitations in the availability of information, not temporal bottlenecks in analysis or comparison. Serial properties likely reflect overt attention expressed in eye movements. PMID:20873936

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

2010-10-01

45

GRAPES: A Software for Parallel Searching on Biological Graphs Targeting Multi-Core Architectures.

Biological applications, from genomics to ecology, deal with graphs that represents the structure of interactions. Analyzing such data requires searching for subgraphs in collections of graphs. This task is computationally expensive. Even though multicore architectures, from commodity computers to more advanced symmetric multiprocessing (SMP), offer scalable computing power, currently published software implementations for indexing and graph matching are fundamentally sequential. As a consequence, such software implementations (i) do not fully exploit available parallel computing power and (ii) they do not scale with respect to the size of graphs in the database. We present GRAPES, software for parallel searching on databases of large biological graphs. GRAPES implements a parallel version of well-established graph searching algorithms, and introduces new strategies which naturally lead to a faster parallel searching system especially for large graphs. GRAPES decomposes graphs into subcomponents that can be efficiently searched in parallel. We show the performance of GRAPES on representative biological datasets containing antiviral chemical compounds, DNA, RNA, proteins, protein contact maps and protein interactions networks. PMID:24167551

Giugno, Rosalba; Bonnici, Vincenzo; Bombieri, Nicola; Pulvirenti, Alfredo; Ferro, Alfredo; Shasha, Dennis

2013-10-22

46

GRAPES: A Software for Parallel Searching on Biological Graphs Targeting Multi-Core Architectures

Biological applications, from genomics to ecology, deal with graphs that represents the structure of interactions. Analyzing such data requires searching for subgraphs in collections of graphs. This task is computationally expensive. Even though multicore architectures, from commodity computers to more advanced symmetric multiprocessing (SMP), offer scalable computing power, currently published software implementations for indexing and graph matching are fundamentally sequential. As a consequence, such software implementations (i) do not fully exploit available parallel computing power and (ii) they do not scale with respect to the size of graphs in the database. We present GRAPES, software for parallel searching on databases of large biological graphs. GRAPES implements a parallel version of well-established graph searching algorithms, and introduces new strategies which naturally lead to a faster parallel searching system especially for large graphs. GRAPES decomposes graphs into subcomponents that can be efficiently searched in parallel. We show the performance of GRAPES on representative biological datasets containing antiviral chemical compounds, DNA, RNA, proteins, protein contact maps and protein interactions networks.

Bombieri, Nicola; Pulvirenti, Alfredo; Ferro, Alfredo; Shasha, Dennis

2013-01-01

47

An intelligent maritime search and rescue directing system

Maritime Search and Rescue (SAR) is the fast, systematical and efficient operations to rescue persons in maritime distress at sea and control the spread of distress incident. This paper introduces an intelligent maritime search and rescue directing system built by Tianjin Maritime Safety Administration. It is an intelligent assistant tool used in the operation of maritime search and rescue. It

Anmin Zhang; Haigang Sui

2006-01-01

48

Parallel graph search: application to intraretinal layer segmentation of 3D macular OCT scans

NASA Astrophysics Data System (ADS)

Image segmentation is of paramount importance for quantitative analysis of medical image data. Recently, a 3-D graph search method which can detect globally optimal interacting surfaces with respect to the cost function of volumetric images has been introduced, and its utility demonstrated in several application areas. Although the method provides excellent segmentation accuracy, its limitation is a slow processing speed when many surfaces are simultaneously segmented in large volumetric datasets. Here, we propose a novel method of parallel graph search, which overcomes the limitation and allows the quick detection of multiple surfaces. To demonstrate the obtained performance with respect to segmentation accuracy and processing speedup, the new approach was applied to retinal optical coherence tomography (OCT) image data and compared with the performance of the former non-parallel method. Our parallel graph search methods for single and double surface detection are approximately 267 and 181 times faster than the original graph search approach in 5 macular OCT volumes (200 x 5 x 1024 voxels) acquired from the right eyes of 5 normal subjects. The resulting segmentation differences were small as demonstrated by the mean unsigned differences between the non-parallel and parallel methods of 0.0 +/- 0.0 voxels (0.0 +/- 0.0 ?m) and 0.27 +/- 0.34 voxels (0.53 +/- 0.66 ?m) for the single- and dual-surface approaches, respectively.

Lee, Kyungmoo; Abràmoff, Michael D.; Garvin, Mona K.; Sonka, Milan

2012-02-01

49

Robot Weightlifting By Direct Policy Search

This paper describes a method for structuring a robot motor learning task. By designing a suitably parameterized policy, we show that a simple search algorithm, along with biologically motivated con- straints, offers an effective means for motor skill acquisition. The framework makes use of the robot counterparts to several elements found in human motor learning: imitation, equilibrium-point con- trol, motor

Michael T. Rosenstein; Andrew G. Barto

2001-01-01

50

Mesh Adaptive Direct Search Algorithms for Constrained Optimization

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

51

APPSPACK 4.0 : asynchronous parallel pattern search for derivative-free optimization.

APPSPACK is software for solving unconstrained and bound constrained optimization problems. It implements an asynchronous parallel pattern search method that has been specifically designed for problems characterized by expensive function evaluations. Using APPSPACK to solve optimization problems has several advantages: No derivative information is needed; the procedure for evaluating the objective function can be executed via a separate program or script; the code can be run in serial or parallel, regardless of whether or not the function evaluation itself is parallel; and the software is freely available. We describe the underlying algorithm, data structures, and features of APPSPACK version 4.0 as well as how to use and customize the software.

Gray, Genetha Anne; Kolda, Tamara Gibson

2004-12-01

52

Parallel architectures for 3-step hierarchical search block-matching algorithm

The paper describes fully pipelined parallel architectures for the 3-step hierarchical search block-matching algorithm, a fast motion estimation algorithm for video coding. The advantage of this algorithm was completely utilized by use of intelligent data arrangement and memory configuration. Techniques for reducing interconnections and external memory accesses were also developed. Because of their low costs, high speeds, and low memory

Her-Ming Jong; Liang-Gee; Tzi-Dar Chiueh

1994-01-01

53

Harmony search algorithm with dynamic subpopulations for scheduling identical parallel machines

In this paper, we study the identical parallel machines scheduling problem for minimizing the makespan. A novel harmony search (HS) algorithm with dynamic subpopulations is proposed to tackle this problem. First, an encoding scheme based on random key representation and list schedule rule is developed, which constructs a mapping scheme between the real-valued harmony vectors and job assignments. Second, the

Jing Chen; Quan-Ke Pan; Huan Li

2010-01-01

54

Parallel direct Poisson solver for discretisations with one Fourier diagonalisable direction

NASA Astrophysics Data System (ADS)

In the context of time-accurate numerical simulation of incompressible flows, a Poisson equation needs to be solved at least once per time-step to project the velocity field onto a divergence-free space. Due to the non-local nature of its solution, this elliptic system is one of the most time consuming and difficult to parallelise parts of the code.In this paper, a parallel direct Poisson solver restricted to problems with one uniform periodic direction is presented. It is a combination of a direct Schur-complement based decomposition (DSD) and a Fourier diagonalisation. The latter decomposes the original system into a set of mutually independent 2D systems which are solved by means of the DSD algorithm. Since no restrictions are imposed in the non-periodic directions, the overall algorithm is well-suited for solving problems discretised on extruded 2D unstructured meshes. The load balancing between parallel processes and the parallelisation strategy are also presented and discussed. The scalability of the solver is successfully tested using up to 8192 CPU cores for meshes with up to 109 grid points. Finally, the performance of the DSD algorithm as 2D solver is analysed by direct comparison with two preconditioned conjugate gradient methods. For this purpose, the turbulent flow around a circular cylinder at Reynolds numbers 3900 and 10,000 are used as problem models.

Borrell, R.; Lehmkuhl, O.; Trias, F. X.; Oliva, A.

2011-06-01

55

Predicted rates for direct WIMP searches

NASA Astrophysics Data System (ADS)

The differential event rate for direct detection of dark matter, both the time averaged and the modulated one due to the motion of the Earth, are discussed. The calculations focus on relatively light cold dark matter candidates (WIMP) and low energy transfers. It is shown that for some WIMP masses the modulation amplitude may change sign. This effect can be exploited to yield information about the mass of the dark matter candidate.

Vergados, J. D.

2012-09-01

56

A Direct Search for Dirac Magnetic Monopoles

Magnetic monopoles are highly ionizing and curve in the direction of the magnetic field. A new dedicated magnetic monopole trigger at CDF, which requires large light pulses in the scintillators of the time-of-flight system, remains highly efficient to monopoles while consuming a tiny fraction of the available trigger bandwidth. A specialized offline reconstruction checks the central drift chamber for large dE/dx tracks which do not curve in the plane perpendicular to the magnetic field. We observed zero monopole candidate events in 35.7 pb{sup -1} of proton-antiproton collisions at {radical}s = 1.96 TeV. This implies a monopole production cross section limit {sigma} < 0.2 pb for monopoles with mass between 100 and 700 GeV, and, for a Drell-Yan like pair production mechanism, a mass limit m > 360 GeV.

Mulhearn, Michael James; /MIT

2004-10-01

57

PARALIGN: rapid and sensitive sequence similarity searches powered by parallel computing technology

PARALIGN is a rapid and sensitive similarity search tool for the identification of distantly related sequences in both nucleotide and amino acid sequence databases. Two algorithms are implemented, accelerated Smith–Waterman and ParAlign. The ParAlign algorithm is similar to Smith–Waterman in sensitivity, while as quick as BLAST for protein searches. A form of parallel computing technology known as multimedia technology that is available in modern processors, but rarely used by other bioinformatics software, has been exploited to achieve the high speed. The software is also designed to run efficiently on computer clusters using the message-passing interface standard. A public search service powered by a large computer cluster has been set-up and is freely available at , where the major public databases can be searched. The software can also be downloaded free of charge for academic use.

Saeb?, Per Eystein; Andersen, Sten Morten; Myrseth, Jon; Laerdahl, Jon K.; Rognes, Torbj?rn

2005-01-01

58

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

[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

59

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

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

60

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

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.

1991-12-31

61

Direct kinematics of a double parallel robot arm for real time velocity control

The determination of the direct kinematics of a parallel mechanism is a difficult problem but must be solved for practical\\u000a application. This paper presents the efficient formulation of the direct kinematics and the Jacobian of a double parallel\\u000a robot arm for velocity control. The robot arm consists of two parallel mechanisms, and a central axis that generates positional\\u000a and orientational

Min Ki Lee; Kun Woo Park

1998-01-01

62

An intelligent maritime search and rescue directing system

NASA Astrophysics Data System (ADS)

Maritime Search and Rescue (SAR) is the fast, systematical and efficient operations to rescue persons in maritime distress at sea and control the spread of distress incident. This paper introduces an intelligent maritime search and rescue directing system built by Tianjin Maritime Safety Administration. It is an intelligent assistant tool used in the operation of maritime search and rescue. It integrates five subsystems - marine communication system, vessel monitoring system, intelligent decision assistant system, on-scene information collecting system, and remote directing system. It is a representative application system of Locate Based Service. This system is successfully applied in Tianjin Maritime Safety Administration and China 2006's BoHai Sea Search and Rescue.

Zhang, Anmin; Sui, Haigang

2006-10-01

63

Do honeybees detect colour targets using serial or parallel visual search?

In humans, visual search tasks are commonly used to address the question of how visual attention is allocated in a specific task and how individuals search for a specific object (;target') among other objects (;distractors') that vary in number and complexity. Here, we apply the methodology of visual search experiments to honeybees, which we trained to choose a coloured disc (target) among a varying number of differently coloured discs (distractors). We measured accuracy and decision time as a function of distractor number and colour. We found that for all colour combinations, decision time increased and accuracy decreased with increasing distractor number, whereas performance increased when more targets were present. These findings are characteristic of a serial search in primates, when stimuli are examined sequentially. We found no evidence for parallel search in bees, which would be characterized by a ;pop out' effect, in which the slope of decision time (and accuracy) over distractor number would be near zero. Additionally, we found that decision time and number of errors were significantly higher when bees had to choose a blue target among yellow distractors compared with the inverse colour combination, a phenomenon known as search asymmetry in humans. PMID:16513924

Spaethe, Johannes; Tautz, Jürgen; Chittka, Lars

2006-03-01

64

A GPU based implementation of direct multi-bit search (DMS) screen algorithm

NASA Astrophysics Data System (ADS)

In this paper, we study the feasibility for using programmable Graphics Processing Unit (GPU) technology for image halftoning, in particular implementing the computationally intense Direct Multi-bit Search (DMS) Screen algorithm. Multi-bit screening is an extension of binary screening, in which every pixel in continuoustone image can be rendered to one among multiple output states. For example, a 2 bit printer is capable of printing with four different drop sizes. In our previous work, we have extended the Direct Binary Search (DBS) to the multi-bit case using Direct Multi-bit Search (DMS) where at every pixel the algorithm chooses the best drop output state to create a visually pleasing halftone pattern without any user defined guidance. This process is repeated throughout the entire range of gray levels while satisfying the stacking constraint to create a high quality multi-bit screen (dither mask). In this paper, we illustrate how employing Graphics Processing Units (GPU) can speed-up intensive DMS image processing operations. Particularly, we illustrate how different modules can be been parallelized. The main goal of many of the previous articles regarding DBS is to decrease the execution time of the algorithm. One of the most common approaches is to decrease the neighborhood size or filter size. The proposed parallel approach allows us to use a large neighborhood and filter size, to achieve the highest halftone quality, while having minimal impact on performance. In addition, we also demonstrate processing several non-overlapping neighborhoods in parallel, by utilizing the GPU's parallel architecture, to further improve the computational efficiency.

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

2013-02-01

65

Improving the efficiency of parallel alternating directions algorithm for time dependent problems

NASA Astrophysics Data System (ADS)

We consider the time dependent Stokes equation on a finite time interval and on a uniform rectangular mesh, written in terms of velocity and pressure. A parallel algorithm based on a direction splitting approach is implemented. Our work is motivated by the need to improve the parallel efficiency of our supercomputer implementation of the parallel algorithm. We are targeting the IBM Blue Gene/P massively parallel computer, which features a 3D torus interconnect. We study the impact of the domain partitioning on the performance of the considered parallel algorithm for solving the time dependent Stokes equation. Here, different parallel partitioning strategies are given special attention. The implementation is tested on the IBM Blue Gene/P and the presented results from numerical tests confirm that decreasing the communication time better parallel properties of the algorithm are obtained.

Ganzha, Maria; Kosturski, Nikola; Lirkov, Ivan

2012-10-01

66

Optimal coordination of directional overcurrent relays using harmony search algorithm

Directional over current relays (DOR) are used to protection of interconnected networks and looped distribution systems. Several techniques and formulations have been proposed to solve the optimal coordination of DOR problem. In this paper, harmony search algorithm (HSA) is proposed for optimal coordination of DOR in a looped distribution system. Then this algorithm is developed to a new Improvised harmony

Mostafa Barzegari; S. M. T Bathaee; Mohsen Alizadeh

2010-01-01

67

Direct Policy Search Reinforcement Learning for Robot Control

In this paper, we present Policy Methods as an alternative to Value Methods to solve Reinforcement Learning problems. The paper proposes a Direct Policy Search algorithm that uses a Neural Network to represent the control policies. De- tails about the algorithm and the update rules are given. The main application of the proposed algorithm is to implement robot control systems,

Andres El-fakdi; Marc Carreras; Narcís Palomeras

2005-01-01

68

Towards Direct Policy Search Reinforcement Learning for Robot Control

This paper proposes a high-level Reinforcement Learning (RL) control system for solving the action selection problem of an autonomous robot. Although the dominant ap- proach, when using RL, has been to apply value function based algorithms, the system here detailed is characterized by the use of Direct Policy Search methods. Rather than approximating a value function, these methodologies approximate a

Andres El-fakdi; Marc Carreras; Pere Ridao

2006-01-01

69

National Technical Information Service (NTIS)

This final report contains reports of research related to the tasks 'Scalable High Performance Computing: Direct and Lark-Eddy Turbulent FLow Simulations Using Massively Parallel Computers' and 'Develop High-Performance Time-Domain Computational Electroma...

P. E. Morgan

2004-01-01

70

Parallel Direct Simulation Monte Carlo Computation Using CUDA on GPUs

NASA Astrophysics Data System (ADS)

In this study computations of the two-dimensional Direct Simulation Monte Carlo (DSMC) method using Graphics Processing Units (GPUs) are presented. An all-device (GPU) computational approach is adopted-where the entire computation is performed on the GPU device, leaving the CPU idle-which includes particle moving, indexing, collisions between particles and state sampling. The subsequent application to GPU computation requires various changes to the original DSMC method to ensure efficient performance on the GPU device. Communications between the host (CPU) and device (GPU) occur only during problem initialization and simulation conclusion when results are only copied from the device to the host. Several multi-dimensional benchmark tests are employed to demonstrate the correctness of the DSMC implementation. We demonstrate here the application of DSMC using a single-GPU, with speedups of 3~10 times as compared to a high-end Intel CPU (Intel Xeon X5472) depending upon the size and the level of rarefaction encountered in the simulation.

Su, C.-C.; Hsieh, C.-W.; Smith, M. R.; Jermy, M. C.; Wu, J.-S.

2011-05-01

71

Search for Very High-z Galaxies with WFC3 Pure Parallel

NASA Astrophysics Data System (ADS)

WFC3 will provide an unprecedented probe to the early universe beyond the current redshift frontier. Here we propose a pure parallel program using this new instrument to search for Lyman-break galaxies at 6.5

Yan, Hao-Jing

2008-07-01

72

A direct search for energetic electrons produced by laboratory sparks

NASA Astrophysics Data System (ADS)

High-voltage sparks in the lab unexpectedly emit x-rays with energies up to several hundred keV. These x-rays have been observed repeatedly and can only be produced by bremsstrahlung, impling the presence of a population of energetic electrons. Such energetic electron and x-ray production may be important for the physics of streamers, spark discharges, and lightning, and has been suggested as directly related to the production of terrestrial gamma-ray flashes. We present the results of the first direct search for energetic electrons produced by a lab spark. Small electrically-isolated scintillators are placed at various locations near the spark gap of a 2 MV Marx generator and the resulting signals are recorded. We present results on the spatial, temporal, and statistical variability of signals produced by energetic electrons and compare our results to predictions of energetic electron production from the literature.

Carlson, B. E.; Kochkin, P.; van Deursen, A. P. J.; Hansen, R.; Gjesteland, T.; Ostgaard, N.

2012-04-01

73

Survey of Search Directions in Interior Point Methods for Linear Programming.

National Technical Information Service (NTIS)

A basic characteristic of an interior point algorithm for linear programming is the search direction. Many papers on interior point algorithms only give an implicit description of the search direction. In the report the authors derive explicit expressions...

D. den Hertog C. Roos

1989-01-01

74

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

Haibo Dong

2003-01-01

75

Currently there exists little support to specify and control the execution of a large number of experiments required for performance oriented development of scientific applications. We have developed a new directive based language called ZEN for the specification of wide sets of synthetic experiments in the context of large scale parameter and performance studies of parallel applications. We report experimental

Radu Prodan; Thomas Fahringer

2005-01-01

76

Clustered-dot halftoning with direct binary search

NASA Astrophysics Data System (ADS)

Printers employing electrophotographic technology typically use clustered-dot screening to avoid potential artifacts caused due to unstable dot rendering. Periodic clustered-dot screens are quite smooth, but also suffer from periodic moire artifacts due to interference with other color channels. Stochastic, clustered-dot screens provide an alternative solution. In this paper, we introduce a new approach for stochastic, clustered-dot halftoning and screen design based on direct binary search. The method deviates from conventional DBS in its use of different filters in different phases of the algorithm. We provide an intuitive explanation for the clustering achieved as a result of this modification, and also discuss ways to control the coarseness of clusters. Due to the non-applicability of conventional screen design procedures to the new halftoning method, we propose a new method for screen design also. Results include images of individually designed constant-tone halftones and halftones of screened folded ramps.

Gupta, Madhur; Staelin, Carl; Fischer, Mani; Shacham, Omri; Jodra, Rodolfo; Allebach, Jan

2010-01-01

77

Direct CP violation searches in charmless hadronic B meson decays

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

78

Interactive-Time Similarity Search for Large Image Collections Using Parallel VA-Files

Nearest-neighbor search (NN-search) plays a key role for co ntent-based retrieval. As a first con- tribution, this article shows that NN-search is a meaningfu l implementation of similarity search, even if features are high-dimensional. But NN-search over high-dimensional features is of linear complexity and query response times have not been satisfactory for large collections of multime- dia objects. This paper,

Roger Weber; Klemens Böhm; Hans-jörg Schek

2000-01-01

79

Parallel perceptrons (PPs) are very simple and efficient committee machines (a single layer of perceptrons with threshold activation functions and binary outputs, and a majority voting decision scheme), which nevertheless behave as universal approximators. The parallel delta (P-Delta) rule is an effective training algorithm, which, following the ideas of statistical learning theory used by the support vector machine (SVM), raises

Manuel Fernandez-Delgado; Jorge Ribeiro; Eva Cernadas; Senén Barro Ameneiro

2011-01-01

80

Direct Searches for Scalar Leptoquarks at the Run II Tevatron

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

81

In this paper, associative memory architecture for a fully parallel nearest Euclidean distance search is proposed. It uses digital circuitry up to subtraction and absolute value calculation in the vector-component comparator part. Analog processing is then applied up to completion of the winner-take-all function. From HSPICE simulation in 0.35 mum CMOS technology the authors confirmed that the winner is detected

Yuki Tanaka; Ali Ahmadi; Tetsushi Koide; Hans Jürgen Mattausch

2006-01-01

82

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

83

High performance massively parallel direct N-body simulations on large GPU clusters.

NASA Astrophysics Data System (ADS)

We present direct astrophysical N-body simulations with up to six million bodies using our parallel MPI/CUDA code on large GPU clusters in China, with different kinds of GPU hardware. These clusters are directly linked under the Chinese Academy of Sciences special GPU cluster program. We reach about one third of the peak GPU performance for this code, in a real application scenario with individual hierarchically block time-steps high (4th, 6th and 8th) order Hermite integration schemes and a real core-halo density structure of the modeled stellar systems.

Berczik, Peter; Nitadori, Keigo; Zhong, Shiyan; Spurzem, Rainer; Hamada, Tsuyoshi; Wang, Xiaowei; Berentzen, Ingo; Veles, Alexander; Ge, Wei

2011-10-01

84

A novel directional asymmetric sampling search algorithm for fast block-matching motion estimation

NASA Astrophysics Data System (ADS)

This paper proposes a novel directional asymmetric sampling search (DASS) algorithm for video compression. Making full use of the error information (block distortions) of the search patterns, eight different direction search patterns are designed for various situations. The strategy of local sampling search is employed for the search of big-motion vector. In order to further speed up the search, early termination strategy is adopted in procedure of DASS. Compared to conventional fast algorithms, the proposed method has the most satisfactory PSNR values for all test sequences.

Li, Yue-E.; Wang, Qiang

2011-11-01

85

Job Search as Goal-Directed Behavior: Objectives and Methods

ERIC Educational Resources Information Center

|This study investigated the relationship between job search objectives (finding a new job/turnover, staying aware of job alternatives, developing a professional network, and obtaining leverage against an employer) and job search methods (looking at job ads, visiting job sites, networking, contacting employment agencies, contacting employers, and…

Van Hoye, Greet; Saks, Alan M.

2008-01-01

86

Chasing a consistent picture for dark matter direct searches

NASA Astrophysics Data System (ADS)

In this paper we assess the present status of dark matter direct searches by means of Bayesian statistics. We consider three particle physics models for spin-independent dark matter interaction with nuclei: elastic, inelastic and isospin violating scattering. We briefly present the state of the art for the three models, marginalizing over experimental systematics and astrophysical uncertainties. Whatever the scenario is, XENON100 appears to challenge the detection region of DAMA, CoGeNT and CRESST. The first aim of this study is to rigorously quantify the significance of the inconsistency between XENON100 data and the combined set of detection (DAMA, CoGeNT and CRESST together), performing two statistical tests based on the Bayesian evidence. We show that XENON100 and the combined set are inconsistent at least at the 2? level in all scenarios but inelastic scattering, for which the disagreement drops to the 1? level. Second we consider only the combined set and hunt the best particle physics model that accounts for the events, using Bayesian model comparison. The outcome between elastic and isospin violating scattering is inconclusive, with the odds 2?1, while inelastic scattering is disfavored with the odds of 1?32 because of CoGeNT data. Our results are robust under reasonable prior assumptions. We conclude that the simple elastic scattering remains the best model to explain the detection regions, since the data do not support extra free parameters. The outcome of consistency tests implies that either a better understanding of astrophysical and experimental uncertainties is needed or the strength of belief in certain data sets should be revised or the dark matter theoretical model is at odds with the data.

Arina, Chiara

2012-12-01

87

In order to acquire their native languages, children must learn richly structured systems with regularities at multiple levels. While structure at different levels could be learned serially, e.g., speech segmentation coming before word-object mapping, redundancies across levels make parallel learning more efficient. For instance, a series of syllables is likely to be a word not only because of high transitional probabilities, but also because of a consistently co-occurring object. But additional statistics require additional processing, and thus might not be useful to cognitively constrained learners. We show that the structure of child-directed speech makes simultaneous speech segmentation and word learning tractable for human learners. First, a corpus of child-directed speech was recorded from parents and children engaged in a naturalistic free-play task. Analyses revealed two consistent regularities in the sentence structure of naming events. These regularities were subsequently encoded in an artificial language to which adult participants were exposed in the context of simultaneous statistical speech segmentation and word learning. Either regularity was independently sufficient to support successful learning, but no learning occurred in the absence of both regularities. Thus, the structure of child-directed speech plays an important role in scaffolding speech segmentation and word learning in parallel.

Yurovsky, Daniel; Yu, Chen; Smith, Linda B.

2012-01-01

88

Parallelized integral-direct CIS(D) calculations with multilayer fragment molecular orbital scheme

We have developed a parallelized integral-direct code of the perturbative doubles correction for configuration interaction\\u000a with singles, proposed as CIS(D) by Head-Gordon et al. (Chem Phys Lett 219:21, 1994). The CIS(D) method provides the energy\\u000a corrections both of the relaxation and differential correlation for the respective CIS excited states. The implementation\\u000a of CIS(D) is based on our original algorithm for the

Yuji Mochizuki; Kiyoshi Tanaka; Katsumi Yamashita; Takeshi Ishikawa; Tatsuya Nakano; Shinji Amari; Katsunori Segawa; Tadashi Murase; Hiroaki Tokiwa; Minoru Sakurai

2007-01-01

89

NASA Astrophysics Data System (ADS)

The modern distributed hydrological models allow the representation of the different surface and subsurface phenomena with great accuracy and high spatial and temporal resolution. Such complexity requires, in general, an equally accurate parametrization. A number of approaches have been followed in this respect, from simple local search method (like Nelder-Mead algorithm), that minimize a cost function representing some distance between model's output and available measures, to more complex approaches like dynamic filters (such as the Ensemble Kalman Filter) that carry on an assimilation of the observations. In this work the first approach was followed in order to compare the performances of three different direct search algorithms on the calibration of a distributed hydrological balance model. The direct search family can be defined as that category of algorithms that make no use of derivatives of the cost function (that is, in general, a black box) and comprehend a large number of possible approaches. The main benefit of this class of methods is that they don't require changes in the implementation of the numerical codes to be calibrated. The first algorithm is the classical Nelder-Mead, often used in many applications and utilized as reference. The second algorithm is a GSS (Generating Set Search) algorithm, built in order to guarantee the conditions of global convergence and suitable for a parallel and multi-start implementation, here presented. The third one is the EGO algorithm (Efficient Global Optimization), that is particularly suitable to calibrate black box cost functions that require expensive computational resource (like an hydrological simulation). EGO minimizes the number of evaluations of the cost function balancing the need to minimize a response surface that approximates the problem and the need to improve the approximation sampling where prediction error may be high. The hydrological model to be calibrated was MOBIDIC, a complete balance distributed model developed at the Department of Civil and Environmental Engineering of the University of Florence. Discussion on the comparisons between the effectiveness of the different algorithms on different cases of study on Central Italy basins is provided.

Campo, Lorenzo; Castelli, Fabio; Caparrini, Francesca

2010-05-01

90

ERIC Educational Resources Information Center

|Grounded on object filtering, automatic indexing, and co-occurrence analysis, an experiment was performed using a parallel supercomputer to analyze over 400,000 abstracts in an INSPEC computer engineering collection. A user evaluation revealed that system-generated thesauri were better than the human-generated INSPEC subject thesaurus in concept…

Chen, Hsinchun; Martinez, Joanne; Kirchhoff, Amy; Ng, Tobun D.; Schatz, Bruce R.

1998-01-01

91

In this work we present two different applications implemented on the neurocomputer Totem Nc3001 from Neuricam Inc. The goal of the experimentation is to test, on real problems, the performance of this powerful parallel unit consisting of 32 Digital Signal Processors (DSPs) and to evaluate its suitability to neural network applications. The first problem implemented is a typical classification algorithm

Giovanni Danese; Ivo De Lotto; Francesco Leporati; Alessio Quaglini; Stefano Ramat; Giampietro Tecchiolli

2001-01-01

92

The bibliography contains citations concerning the development and performance analysis of parallel architecture in image processing and computing. Cost and performance evaluations of multiple processor systems are described. Applications are described, including supercomputer design, database management, computer communication systems, and robot control. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1993-10-01

93

Solar neutrions as background in direct dark matter searches

The coherent contribution of all neutrons in neutrino nucleus scattering due to the neutral current is examined considering the boron solar neutrinos. These neutrinos could potentially become a source of background in the future dark matter searches aiming at nucleon cross sections in the region well below the 10{sup -10} pb, i.e a few events per ton per year.

Vergados, J. D. [Physics Department, University of Ioannina, Ioannina, GR 451 10, Greece and Theory Division, CERN 1211, Geneva 23 (Greece); Ejiri, H. [TRCNP, Osaka University, Osaka, 567-0047 (Japan) and National Institute of Radiological Sciences, Chiba, 263-8555 (Japan); Giomataris, I. [IRFU, Centre d' etudes de Saclay, 91191 Gif sur Yvette CEDEX (France)

2009-04-17

94

Previous research has predicted that direct product experience will be superior to advertising in communicating information about products. In experiment 1 of the present study, claims about search attributes were better recognized and beliefs about search attributes were more accessible and more confidently held after exposure to ads in comparison with direct experience of two inexpensive packaged products. Experiment 2

Alice A. Wright

1995-01-01

95

Dynamic Data Structures for a Direct Search Algorithm

The DIRECT (DIviding RECTangles) algorithm of Jones, Perttunen, and Stuckman (Journal of Optimization Theory and Applications, vol. 79, no. 1, pp. 157–181, 1993), a variant of Lipschitzian methods for bound constrained global optimization, has proved effective even in higher dimensions. However, the performance of a DIRECT implementation in real applications depends on the characteristics of the objective function, the problem

Jian He; Layne T. Watson; Naren Ramakrishnan; Clifford A. Shaffer; Alex Verstak; Jing Jiang; Kyung Bae; William H. Tranter

2002-01-01

96

Dynamic Data Structures for a Direct Search Algorithm

The DIRECT (DIviding RECTangles) algorithm of Jones, Perttunen, and Stuckman (Journal of Opti- mization Theory and Applications, vol. 79, no. 1, pp. 157-181, 1993), a variant of Lipschitzian methods for bound constrained global optimization, has proved effective even in higher dimensions. However, the performance of a DIRECT implementation in real applications depends on the characteristics of the objective function, the

JIAN HE; LAYNE T. WATSON; NAREN RAMAKRISHNAN; CLIFFORD A. SHAFFER; ALEX VERSTAK; JING JIANG; KYUNG BAE; WILLIAM H. TRANTER

2002-01-01

97

The Parallel Evolution of Search Engines and Digital Libraries: Their Convergence to the Mega-Portal

The information era has brought with it the well-known problem of 'Information Explosion'. There are many and varied Search Engines (SEs) on the Internet but it is still hard to locate and concentrate only on materials relevant to a specific task. Digital Libraries (DLs) could better provide such services on the Web. However, DLs have been much less researched and

Uri Hanani; Ariel J. Frank

2000-01-01

98

In this article, we explore the interplay between searches for supersymmetric particles and Higgs bosons at hadron colliders (the Tevatron and the LHC) and direct dark matter searches (such as CDMS, ZEPLIN, XENON, EDELWEISS, CRESST, WARP and others). We focus on collider searches for heavy MSSM Higgs bosons (A, H, H{sup {+-}}) and how the prospects for these searches are impacted by direct dark matter limits and vice versa. We find that the prospects of these two experimental programs are highly interrelated. A positive detection of A, H or H{sup {+-}} at the Tevatron would dramatically enhance the prospects for a near future direct discovery of neutralino dark matter. Similarly, a positive direct detection of neutralino dark matter would enhance the prospects of discovering heavy MSSM Higgs bosons at the Tevatron or the LHC. Combining the information obtained from both types of experimental searches will enable us to learn more about the nature of supersymmetry.

Carena, Marcela; Hooper, Dan; /Fermilab; Vallinotto, Alberto; /Fermilab /Chicago U. /Paris, Inst. Astrophys.

2006-11-01

99

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 summary Title 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

100

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

101

Local Search in Weighted and Directed Social Networks: The Case of Enron Email Networks

Although they have small-world and searchable characteristics, social networks always protect local structure which makes local search very hard. Social networks not only have power-law distribution, but also have higher connectivity or clustering characteristics. Meanwhile, several social networks are weighted and directed. Hence we should utilize these extra information. In this paper, we propose and theoretically analyze local search strategies

Ning Zhong; Rui Guo; Wenbin Li

2009-01-01

102

In this work, image-space-parallel direct volume rendering (DVR) of unstructured grids is investigated for distributed-memory architectures. A hypergraph-partitioning-based model is proposed for the adaptive screen partitioning problem in this context. The proposed model aims to balance the rendering loads of processors while trying to minimize the amount of data replication. In the parallel DVR framework we adopted, each data primitive

Berkant Barla Cambazoglu; Cevdet Aykanat

2007-01-01

103

A Scalable Distributed Parallel Breadth-First Search Algorithm on BlueGene/L

Many emerging large-scale data science applications require searching large graphs distributed across multiple memories and processors. This paper presents a distributed breadth-first search (BFS) scheme that scales for random graphs with up to three billion vertices and 30 billion edges. Scalability was tested on IBM BlueGene/L with 32,768 nodes at the Lawrence Livermore National Laboratory. Scalability was obtained through a series of optimizations, in particular, those that ensure scalable use of memory. We use 2D (edge) partitioning of the graph instead of conventional 1D (vertex) partitioning to reduce communication overhead. For Poisson random graphs, we show that the expected size of the messages is scalable for both 2D and 1D partitionings. Finally, we have developed efficient collective communication functions for the 3D torus architecture of BlueGene/L that also take advantage of the structure in the problem. The performance and characteristics of the algorithm are measured and reported.

Yoo, A; Chow, E; Henderson, K; McLendon, W; Hendrickson, B; Catalyurek, U

2005-07-19

104

Constraints on scalar dark matter from direct experimental searches

NASA Astrophysics Data System (ADS)

The standard model (SM) plus a real gauge-singlet scalar field dubbed darkon (SM+D) is the simplest model possessing a weakly interacting massive particle (WIMP) dark-matter candidate. The upper limits for the WIMP-nucleon elastic cross section as a function of WIMP mass from the recent XENON10 and CDMS II experiments rule out darkon mass ranges from 10 to (50, 70, 75) GeV for Higgs-boson masses of (120, 200, 350) GeV, respectively. This may exclude the possibility of the darkon providing an explanation for the gamma-ray excess observed in the EGRET data. We show that by extending the SM+D to a two-Higgs-doublet model plus a darkon the experimental constraints on the WIMP-nucleon interactions can be circumvented due to suppression occurring at some values of the product tan??tan??, with ? being the neutral-Higgs mixing angle and tan?? the ratio of vacuum expectation values of the Higgs doublets. We also comment on the implication of the darkon model for Higgs searches at the LHC.

He, Xiao-Gang; Li, Tong; Li, Xue-Qian; Tandean, Jusak; Tsai, Ho-Chin

2009-01-01

105

Constraints on Scalar Dark Matter from Direct Experimental Searches

NASA Astrophysics Data System (ADS)

The standard model (SM) plus a real gauge-singlet scalar field dubbed darkon (SM+D) is the simplest model possessing a weakly interacting massive particle (WIMP) dark-matter candidate. The upper limits for the WIMP-nucleon elastic cross-section as a function of WIMP mass from the recent XENON10 and CDMS II experiments rule out darkon mass ranges from 10 to (50, 70, 75) GeV for Higgs-boson masses of (120, 200, 350) GeV, respectively. This may exclude the possibility of the darkon providing an explanation for the gamma-ray excess observed in the EGRET data. We show that by extending the SM+D to a two-Higgs-doublet model plus a darkon the experimental constraints on the WIMP-nucleon interactions can be circumvented due to suppression occurring at some values of the product tan ? tan ?, with ? being the neutral-Higgs mixing angle and tan ? the ratio of vacuum expectation values of the Higgs doublets. We also comment on the implication of the darkon model for Higgs searches at the LHC.

He, Xiao-Gang; Li, Tong; Li, Xue-Qian; Tandean, Jusak; Tsai, Ho-Chin

106

Direct method for string to deterministic finite automaton conversion for fast text searching.

National Technical Information Service (NTIS)

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...

G. J. Berlin

1991-01-01

107

Motivation: Peptide mass fingerprinting (PMF) is a method for protein identification in which a protein is fragmented by a defined cleavage protocol (usually proteolysis with trypsin), and the masses of these products constitute a ‘fingerprint’ that can be searched against theoretical fingerprints of all known proteins. In the first stage of PMF, the raw mass spectrometric data are processed to generate a peptide mass list. In the second stage this protein fingerprint is used to search a database of known proteins for the best protein match. Although current software solutions can typically deliver a match in a relatively short time, a system that can find a match in real time could change the way in which PMF is deployed and presented. In a paper published earlier we presented a hardware design of a raw mass spectra processor that, when implemented in Field Programmable Gate Array (FPGA) hardware, achieves almost 170-fold speed gain relative to a conventional software implementation running on a dual processor server. In this article we present a complementary hardware realization of a parallel database search engine that, when running on a Xilinx Virtex 2 FPGA at 100 MHz, delivers 1800-fold speed-up compared with an equivalent C software routine, running on a 3.06 GHz Xeon workstation. The inherent scalability of the design means that processing speed can be multiplied by deploying the design on multiple FPGAs. The database search processor and the mass spectra processor, running on a reconfigurable computing platform, provide a complete real-time PMF protein identification solution. Contact: d.coca@sheffield.ac.uk

Bogdan, Istvan A.; Rivers, Jenny; Beynon, Robert J.; Coca, Daniel

2008-01-01

108

Motivation: Peptide mass fingerprinting (PMF) is a method for protein identification in which a protein is fragmented by a defined cleavage protocol (usually proteolysis with trypsin), and the masses of these products constitute a 'fingerprint' that can be searched against theoretical fingerprints of all known proteins. In the first stage of PMF, the raw mass spectrometric data are processed to generate a peptide mass list. In the second stage this protein fingerprint is used to search a database of known proteins for the best protein match. Although current software solutions can typically deliver a match in a relatively short time, a system that can find a match in real time could change the way in which PMF is deployed and presented. In a paper published earlier we presented a hardware design of a raw mass spectra processor that, when implemented in Field Programmable Gate Array (FPGA) hardware, achieves almost 170-fold speed gain relative to a conventional software implementation running on a dual processor server. In this article we present a complementary hardware realization of a parallel database search engine that, when running on a Xilinx Virtex 2 FPGA at 100 MHz, delivers 1800-fold speed-up compared with an equivalent C software routine, running on a 3.06 GHz Xeon workstation. The inherent scalability of the design means that processing speed can be multiplied by deploying the design on multiple FPGAs. The database search processor and the mass spectra processor, running on a reconfigurable computing platform, provide a complete real-time PMF protein identification solution. PMID:18453553

Bogdán, István A; Rivers, Jenny; Beynon, Robert J; Coca, Daniel

2008-05-03

109

Lower Bounds for Hit-and-Run Direct Search

“Hit-and-run is fast and fun” to generate a random point in a high dimensional convex set K (Lovász\\/Vempala, MSR-TR-2003-05). More precisely, the hit-and-run random walk mixes fast independently of where it is started\\u000a inside the convex set. To hit-and-run from a point \\u000a x e<\\/font\\u000a>Rn{x} \\\\varepsilon {\\\\mathcal{R}}^{n}\\u000a , a line L through x is randomly chosen (uniformly over all directions). Subsequently,

Jens Jägersküpper

2007-01-01

110

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

111

Three-dimensional parallel distributed inversion of CSEM data using a direct forward solver

NASA Astrophysics Data System (ADS)

For 3-D inversion of controlled-source electromagnetic (CSEM) data, increasing availability of high-performance computers enables us to apply inversion techniques that are theoretically favourable, yet have previously been considered to be computationally too demanding. We present a newly developed parallel distributed 3-D inversion algorithm for interpreting CSEM data in the frequency domain. Our scheme is based on a direct forward solver and uses Gauss-Newton minimization with explicit formation of the Jacobian. This combination is advantageous, because Gauss-Newton minimization converges rapidly, limiting the number of expensive forward modelling cycles. Explicit calculation of the Jacobian allows us to (i) precondition the Gauss-Newton system, which further accelerates convergence, (ii) determine suitable regularization parameters by comparing matrix norms of data- and model-dependent terms in the objective function and (iii) thoroughly analyse data sensitivities and interdependencies. We show that explicit Jacobian formation in combination with direct solvers is likely to require less memory than combinations of direct solvers and implicit Jacobian usage for many moderate-scale CSEM surveys. We demonstrate the excellent convergence properties of the new inversion scheme for several synthetic models. We compare model updates determined by solving either a system of normal equations or, alternatively, a linear least-squares system. We assess the behaviour of three different stabilizing functionals in the framework of our inversion scheme, and demonstrate that implicit regularization resulting from incomplete iterative solution of the model update equations helps stabilize the inversion. We show inversions of models with up to two million unknowns in the forward solution, which clearly demonstrates applicability of our approach to real-world problems.

Grayver, A. V.; Streich, R.; Ritter, O.

2013-06-01

112

Taming astrophysical bias in direct dark matter searches

NASA Astrophysics Data System (ADS)

We explore systematic biases in the identification of dark matter in future direct detection experiments and compare the reconstructed dark matter properties when assuming a self-consistent dark matter distribution function and the standard Maxwellian velocity distribution. We find that the systematic bias on the dark matter mass and cross-section determination arising from wrong assumptions for its distribution function is of order ~ 1?. A much larger systematic bias can arise if wrong assumptions are made on the underlying Milky Way mass model. However, in both cases the bias is substantially mitigated by marginalizing over galactic model parameters. We additionally show that the velocity distribution can be reconstructed in an unbiased manner for typical dark matter parameters. Our results highlight both the robustness of the dark matter mass and cross-section determination using the standard Maxwellian velocity distribution and the importance of accounting for astrophysical uncertainties in a statistically consistent fashion.

Pato, Miguel; Strigari, Louis E.; Trotta, Roberto; Bertone, Gianfranco

2013-02-01

113

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

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

114

Implementation of unsteady sampling procedures for the parallel direct simulation Monte Carlo method

NASA Astrophysics Data System (ADS)

An unsteady sampling routine for a general parallel direct simulation Monte Carlo method called PDSC is introduced, allowing the simulation of time-dependent flow problems in the near continuum range. A post-processing procedure called DSMC rapid ensemble averaging method (DREAM) is developed to improve the statistical scatter in the results while minimising both memory and simulation time. This method builds an ensemble average of repeated runs over small number of sampling intervals prior to the sampling point of interest by restarting the flow using either a Maxwellian distribution based on macroscopic properties for near equilibrium flows (DREAM-I) or output instantaneous particle data obtained by the original unsteady sampling of PDSC for strongly non-equilibrium flows (DREAM-II). The method is validated by simulating shock tube flow and the development of simple Couette flow. Unsteady PDSC is found to accurately predict the flow field in both cases with significantly reduced run-times over single processor code and DREAM greatly reduces the statistical scatter in the results while maintaining accurate particle velocity distributions. Simulations are then conducted of two applications involving the interaction of shocks over wedges. The results of these simulations are compared to experimental data and simulations from the literature where there these are available. In general, it was found that 10 ensembled runs of DREAM processing could reduce the statistical uncertainty in the raw PDSC data by 2.5 3.3 times, based on the limited number of cases in the present study.

Cave, H. M.; Tseng, K.-C.; Wu, J.-S.; Jermy, M. C.; Huang, J.-C.; Krumdieck, S. P.

2008-06-01

115

NASA Astrophysics Data System (ADS)

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., ?) for Doppler observations of stars potentially harboring multiple planetary companions (assuming negligible planet planet interactions). Given the high-dimensionality of the model parameter space (at least five dimensions per planet), a global search is extremely computationally demanding. We expect that the underlying Kepler solver and model evaluator will be combined with a wide variety of more sophisticated algorithms to provide efficient global search, parameter estimation, model comparison, and adaptive experimental design for radial velocity and/or astrometric planet searches. We tested multiple implementations using single precision, double precision, pairs of single precision, and mixed precision arithmetic. We find that the vast majority of computations can be performed using single precision arithmetic, with selective use of compensated summation for increased precision. However, standard single precision is not adequate for calculating the mean anomaly from the time of observation and orbital period when evaluating the goodness-of-fit for real planetary systems and observational data sets. Using all double precision, our GPU code outperforms a similar code using a modern CPU by a factor of over 60. Using mixed precision, our GPU code provides a speed-up factor of over 600, when evaluating n>1024 models planetary systems each containing n=4 planets and assuming n=256 observations of each system. We conclude that modern GPUs also offer a powerful tool for repeatedly evaluating Kepler’s equation and a goodness-of-fit statistic for orbital models when presented with a large parameter space.

Ford, Eric B.

2009-05-01

116

The Parallel Perceptron (PP) is a simple neural network which has been shown to be a universal approximator, and it can be trained using the Parallel Delta (P-Delta) rule. This rule tries to maximize the distance between the perceptron activations and their decision hyperplanes in order to increase its generalization ability, following the principles of the Statistical Learning Theory. In

M. Ferna?ndez-Delgado; J. Ribeiro; E. Cernadas; S. Barro

2010-01-01

117

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

118

Segmentation in a Labor Market with Two-Sided Heterogeneity: Directed vs. Undirected Search1

Abstract I propose a model of a frictional labor market with a continuum,of workers types where segmentation depends on the ability of the workers to direct their search strategies to,rms adopting dierent,technologies. When search is undirected and more than one type of vacancy is posted, the equilibrium is partially segmented. On the other hand, the equilibrium is segmented when workers

Luca Paolo Merlino

2008-01-01

119

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

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 direct-write 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. PMID:21574626

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

2011-05-16

120

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

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

1991-01-01

121

ERIC Educational Resources Information Center

This study examined the effects of the test administrator's attitudes toward Holland's Self-Directed Search, the size of the group taking the instrument, and whether or not monitors were used during the administration on both self-scoring accuracy and satisfaction with results. Only monitoring reduced self-scoring errors, and none affected…

Christensen, Kathleen C.; And Others

1975-01-01

122

A Note on the Validity of the Self-Directed Search

ERIC Educational Resources Information Center

The scales of the Self-Directed Search (SDS) correlate with the scales of the Kuder, the Thurstone Temperament Schedule, the Bennett Mechanical Comprehension Test, and the Minnesota Paper Form Board in predictable ways across three small samples of high school students. The results support the validity of the SDS. (Author)

Holland, John L.; Nafziger, Dean H.

1975-01-01

123

In the present paper low cost cage induction motor design problem is approached using direct search methods, which do not require to calculate the derivatives of the function, and indirect method-a penalty function approach. Induction motor design is considered as a nonlinear, multivariable constrained optimisation problem with ampere conductors per meter, ratios stack length to pole pitch and stator slot

D. G. BHARADWAJ; K. VENKATESAN; R. B. SAXENA

1979-01-01

124

Effects of the self-directed search on high school students

Compared the effects on 959 high school students of the Self-Directed Search (SDS), a self-administered vocational counseling simulation; the Vocational Preference Inventory (VPI); and no treatment. Students taking the SDS or the VPI evaluated the instruments as moderately positive, reported feeling more satisfied with their current occupational choice, and were considering more occupational alternatives than the control group both the

Thelma B. Zener; Leslie Schnuelle

1976-01-01

125

Implementation of an ADI (Alternating Direction Implicit) Method on Parallel Computers.

National Technical Information Service (NTIS)

The implementation of an ADI method for solving the diffusion equation on three parallel/vector computers is discussed. The computers were chosen so as to encompass a variety of architectures. They are: the MPP, an SIMD machine with 16K bit serial process...

R. A. Fatoohi C. E. Grosch

1987-01-01

126

In the framework of coupled large-eddy\\/discrete ordinates method (LES\\/DOM) computations of turbulent combustion problems, various decompositions for parallel calculations of the radiative heat transfer based on the DOM are investigated. The methods analyzed are: (A) a task decomposition on the discrete directions and frequencies with two numeric strategies: Message Passing Interface (MPI) with distributed memory and OpenMP with shared memory

Damien Poitou; Jorge Amaya; Florent Duchaine

2012-01-01

127

PeliGRIFF, a parallel DEM-DLM\\/FD direct numerical simulation tool for 3D particulate flows

The problem of particulate flows at moderate to high concentration and finite Reynolds number is addressed by parallel direct\\u000a numerical simulation. The present contribution is an extension of the work published in Computers & Fluids 38:1608 (2009), where systems of moderate size in a 2D geometry were examined. At the numerical level, the suggested method is inspired\\u000a by the framework

Anthony Wachs

128

Solar and atmospheric neutrinos: Background sources for the direct dark matter searches

NASA Astrophysics Data System (ADS)

In experiments for direct dark matter searches, neutrinos coherently scattering off nuclei can produce similar events as Weakly Interacting Massive Particles (WIMPs). The calculated count rate for solar neutrinos in such experiments is a few events per ton-year. This count rate strongly depends on the nuclear recoil energy threshold achieved in the experiments for the WIMP search. We show that solar neutrinos can be a serious background source for direct dark matter search experiments using Ge, Ar, Xe and CaWO 4 as target materials. To reach sensitivities better than ˜10 -10 pb for the elastic WIMP nucleon spin-independent cross section in the zero-background limit, energy thresholds for nuclear recoils should be ?2.05 keV for CaWO 4, ?4.91 keV for Ge, ?2.89 keV for Xe, and ?8.62 keV for Ar as target material. Next-generation experiments should not only strive for a reduction of the present energy thresholds but mainly focus on an increase of the target mass. Atmospheric neutrinos limit the achievable sensitivity for the background-free direct dark matter search to ?10 -12 pb.

Gütlein, A.; Ciemniak, C.; von Feilitzsch, F.; Haag, N.; Hofmann, M.; Isaila, C.; Lachenmaier, T.; Lanfranchi, J.-C.; Oberauer, L.; Pfister, S.; Potzel, W.; Roth, S.; von Sivers, M.; Strauss, R.; Zöller, A.

2010-09-01

129

Multiparty controlled quantum secure direct communication based on quantum search algorithm

NASA Astrophysics Data System (ADS)

In this study, a new controlled quantum secure direct communication (CQSDC) protocol using the quantum search algorithm as the encoding function is proposed. The proposed protocol is based on the multi-particle Greenberger-Horne-Zeilinger entangled state and the one-step quantum transmission strategy. Due to the one-step transmission of qubits, the proposed protocol can be easily extended to a multi-controller environment, and is also free from the Trojan horse attacks. The analysis shows that the use of quantum search algorithm in the construction of CQSDC appears very promising.

Kao, Shih-Hung; Hwang, Tzonelih

2013-09-01

130

Parallel spatial direct numerical simulation of boundary-layer flow transition on IBM SP1

The spatially evolving disturbances that are associated with laminar-to-turbulent transition in three-dimensional boundary-layer flows are computed with the PSDNS code on an IBM SP1 parallel supercomputer. By remapping the distributed data structure during the course of the calculation, optimized serial library routines can be utilized that substantially increase the computational performance. Although the remapping incurs a high communication penalty, the parallel efficiency of the code remains above 40 percent for all performed calculations. By using appropriate compile options and optimized library routines, the serial code achieves 52-56 Mflops 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. Comparisons to the Cray Y/MP and Cray C-90 are made for this large scale simulation.

Hanebutte, U.R. [Argonne National Lab., IL (United States); Joslin, R.D. [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center; Zubair, M. [International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center

1995-07-01

131

Influence of massively parallel e-beam direct-write pixel size on electron proximity correction

Massively E-beam maskless lithography (MEBML2) is one of the potential solutions for 32-nm half-pitch and beyond. In the past, its relatively low throughput restricted EBDW development to mostly mask making, small volume wafer production and prototyping. Recently the production worthy ML2 approaches, >10,000 e-beams writing in parallel, have been proposed by MAPPER, KLA and IMS. These approaches use raster scan

S. J. Lin; P. S. Chen; J. J. Shin; W. C. Wang; Burn J. Lin

2011-01-01

132

Effect of Direct-to-Consumer Drug Advertising Exposure on Information Search

Objective: To compare the effectiveness of disease-specific (help-seeking) direct-to-consumer drug advertising (DTCA) and product-specific (product-claim) DTCA to stimulate postexposure external information search behaviors regarding drug and disease information from physicians, pharmacists, nurses, family, and friends, as well as the use of medical references and the Internet in the United States.Methods: A two-group, posttest-only experimental design was used (380 adult asthma

Clive M. Mendonca; David J. McCaffrey; Benjamin F. Banahan; John P. Bentley; Yi Yang

2011-01-01

133

A Self-adaptive Evolutionary Programming Based on Optimum Search Direction

The Classical Evolutionary Programming (CEP) relies on Gaussian mutation, whereas Fast Evolutionary Programming (FEP) selects\\u000a Cauchy distribution as the primary mutation operator, Improved Fast Evolutionary (IFEP) selects the better Gaussian and Cauchy\\u000a distribution as the primary mutation operator. In this paper, we propose a self-adaptive Evolutionary Programming based on\\u000a Optimum Search Direction (OSDEP) in which we introduce the current best

Guangming Lin; Xin Lu; Yongsheng Liang; Lishan Kang; Xin Yao

2008-01-01

134

Interests, Aspirations, Self-Estimates, and the Self-Directed Search

This article discusses the meaning of vocational aspirations, competency self-estimates, and ability self-ratings assessed by the Self-Directed Search (SDS). It describes views on the role of learning in the development of vocational interests expressed by E. L. Thorndike and E. K. Strong and the more recent views on interest development expressed by J. L. Holland. The article suggests that self-estimates

Gary D. Gottfredson

2002-01-01

135

Search for direct CP violation in non-leptonic decays of charged Xi and Lambda hyperons

A search for direct CP violation in the non-leptonic decays of hyperons has been performed. In comparing the product of the decay parameters, {alpha}{sub {Xi}} {alpha}{sub {Lambda}}, in terms of an asymmetry parameter, A{sub {Xi}{Lambda}}, between hyperons and anti-hyperons in the charged {Xi} {yields} {Lambda}{pi} and {Lambda} {yields} p{sub {pi}} decay sequence, we found no evidence of direct CP violation. The parameter A{sub {Xi}{Lambda}} was measured to be 0.012 {+-} 0.014.

Luk, K.B.; Diehl, H.T.; Duryea, J.; Guglielmo, G.; Heller, K.; Ho, P.M.; James, C.; Johns, K.; Longo, M.J.; Rameika, R.; Teige, S.; Thomson, G.B.; Zou, Y.; Fermilab E756 Collaboration

2000-12-04

136

Search for Direct CP Violation in Nonleptonic Decays of Charged {Xi} and {Lambda} Hyperons

A search for direct CP violation in the nonleptonic decays of hyperons has been performed. In comparing the product of the decay parameters, {alpha}{sub {Xi}}{alpha}{sub {Lambda}} , in terms of an asymmetry parameter, A{sub {Xi}{Lambda}} , between hyperons and antihyperons in the charged {Xi}{yields}{Lambda}{pi} and {Lambda}{yields}p{pi} decay sequence, we found no evidence of direct CP violation. The parameter A{sub {Xi}{Lambda}} was measured to be 0.012{+-}0.014 .

Luk, K. B.; Diehl, H. T.; Duryea, J.; Guglielmo, G.; Heller, K.; Ho, P. M.; James, C.; Johns, K.; Longo, M. J.; Rameika, R. (and others)

2000-12-04

137

Constraining Sommerfeld enhanced annihilation cross-sections of dark matter via direct searches

NASA Astrophysics Data System (ADS)

In a large class of models we show that the light scalar field responsible for the Sommerfeld enhancement in the annihilation of dark matter leads to observable direct detection rates, due to its mixing with the standard model Higgs. As a result the large annihilation cross-section of dark matter at present epoch, required to explain the observed cosmic ray anomalies, can be strongly constrained by direct searches. In particular Sommerfeld boost factors of order of a few hundred are already out of the CDMS-II upper bound at 90% confidence level for reasonable values of the model parameters.

Arina, Chiara; Josse-Michaux, François-Xavier; Sahu, Narendra

2010-08-01

138

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

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

139

An efficient parallel motion estimation algorithm for digital image processing

The authors present an efficient block-matching algorithm called the parallel hierarchical one-dimensional search (PHODS) for motion estimation. Instead of finding the two-dimensional motion vector directly, the PHODS finds two one-dimensional displacements in parallel on the two axes (say x and y) independently within the search area. The major feature of this algorithm is that its search speed for the motion

Liang-Gee Chen; Wai-Ting Chen; Yeu-Shen Jehng; Tzi-Dar Chiuch

1991-01-01

140

NASA Astrophysics Data System (ADS)

As one of the important tasks in digital terrain analysis, the calculation of flow accumulations from gridded digital elevation models (DEMs) usually involves two steps in a real application: (1) using an iterative DEM preprocessing algorithm to remove the depressions and flat areas commonly contained in real DEMs, and (2) using a recursive flow-direction algorithm to calculate the flow accumulation for every cell in the DEM. Because both algorithms are computationally intensive, quick calculation of the flow accumulations from a DEM (especially for a large area) presents a practical challenge to personal computer (PC) users. In recent years, rapid increases in hardware capacity of the graphics processing units (GPUs) provided in modern PCs have made it possible to meet this challenge in a PC environment. Parallel computing on GPUs using a compute-unified-device-architecture (CUDA) programming model has been explored to speed up the execution of the single-flow-direction algorithm (SFD). However, the parallel implementation on a GPU of the multiple-flow-direction (MFD) algorithm, which generally performs better than the SFD algorithm, has not been reported. Moreover, GPU-based parallelization of the DEM preprocessing step in the flow-accumulation calculations has not been addressed. This paper proposes a parallel approach to calculate flow accumulations (including both iterative DEM preprocessing and a recursive MFD algorithm) on a CUDA-compatible GPU. For the parallelization of an MFD algorithm (MFD-md), two different parallelization strategies using a GPU are explored. The first parallelization strategy, which has been used in the existing parallel SFD algorithm on GPU, has the problem of computing redundancy. Therefore, we designed a parallelization strategy based on graph theory. The application results show that the proposed parallel approach to calculate flow accumulations on a GPU performs much faster than either sequential algorithms or other parallel GPU-based algorithms based on existing parallelization strategies.

Qin, Cheng-Zhi; Zhan, Lijun

2012-06-01

141

Search for direct gamma production at low transverse momentum in 63-GeV pp collisions

We have searched for direct photons of low P/sub T/ (less than or equal to1.0 GeV/c) at theta/sub c.m./ = 90/sup 0/ in pp collisions at ..sqrt..s = 63 GeV. We used two independent methods: direct detection in NaI crystals and conversion to e/sup +/e/sup -/ pairs. No signal is observed; the photon spectrum is well described by the decay of hadrons. The result is consistent with a direct low-P/sub T/ photon signal reported at ..sqrt..s = 12 GeV, but excludes a rapid growth of soft-photon production with ..sqrt..s .

Akesson, T.; Albrow, c.M.G.; Almehed, k.S.; Anassontzis, m.E.; Batley, l.R.; Benary, c.O.; Boggild, p.H.; Botner, f.O.; Breuker, f.H.; Burkert, c.V.; and others

1987-11-01

142

The Impact of Transiting Planet Science on the Next Generation of Direct-Imaging Planet Searches

NASA Astrophysics Data System (ADS)

Within the next five years, a number of direct-imaging planet search instruments, like the VLT SPHERE instrument, will be coming online. To successfully carry out their programs, these instruments will rely heavily on a-priori information on planet composition, atmosphere, and evolution. Transiting planet surveys, while covering a different semi-major axis regime, have the potential to provide critical foundations for these next-generation surveys. For example, improved information on planetary evolutionary tracks may significantly impact the insights that can be drawn from direct-imaging statistical data. Other high-impact results from transiting planet science include information on mass-to-radius relationships as well as atmospheric absorption bands. The marriage of transiting planet and direct-imaging results may eventually give us the first complete picture of planet migration, multiplicity, and general evolution.

Carson, Joseph C.

2009-02-01

143

The XENON10 WIMP Direct Detection Search at the Gran Sasso Underground Laboratory

The direct detection search for WIMPs with the XENON10 detector has produced among the best results in the field to date. The detector is a dual-phase liquid xenon time projection chamber, capable of 3-D position reconstruction and nuclear recoil discrimination. We summarize 58.6 live-days of WIMP search data collected at the Gran Sasso Underground Laboratory (LNGS) in Italy. With this data we have been able to set stringent upper limits on the spin-dependent and spin-independent WIMP scattering cross sections, in addition to a lower limit of 2.2 TeV/c{sup 2} on the mass of the heavy Majorana neutrino.

Manalaysay, Aaron [Department of Physics, University of Florida, Gainesville, FL 32611 (United States) and Physics Institute, University of Zuerich, Zuerich, CH-8057 (Switzerland)

2009-09-08

144

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

2012-10-02

145

Influence of massively parallel e-beam direct-write pixel size on electron proximity correction

NASA Astrophysics Data System (ADS)

Massively E-beam maskless lithography (MEBML2) is one of the potential solutions for 32-nm half-pitch and beyond. In the past, its relatively low throughput restricted EBDW development to mostly mask making, small volume wafer production and prototyping. Recently the production worthy ML2 approaches, >10,000 e-beams writing in parallel, have been proposed by MAPPER, KLA and IMS. These approaches use raster scan in pattern writing. Hence the bitmap is certainly the final data format. The bitmap format used to have huge data volume with fine pixel size to maintain the CD accuracy after electron proximity correction (EPC). Data handling becomes necessary, especially on data transmission rate. The aggregated data transmission rate would be up to 1963 Tera bits per second (bps) for a 10 WPH tool using 1-nm pixel size and 1-bit gray level. It needs 19,630 fibers each transmitting 10 Gbps. The data rate per beam would be >20 Gbps in 10,000-beam MEBML2. Hence data reduction using bigger pixel size to achieve sub-nm EPC accuracy is crucial for reducing the fiber number to the beam number. In this paper, the writing-error-enhanced-factor to quantitatively characterize the impact of CD accuracy by various total blur in resist is reported; and we propose the vernier pattern to verify sub-nm CD accuracy and the in-house dithering raster method to achieve sub-0.2-nm CD accuracy using multiple-nm pixel sizes, which could reduce the need of the aggregated data rate to 11%, 33%, 44% and 79% of 1963 Tbps on 22-nm, 16-nm, 11-nm, 8-nm node respectively.

Lin, S. J.; Chen, P. S.; Shin, J. J.; Wang, W. C.; Lin, Burn J.

2011-03-01

146

Massive liquid Ar and Xe detectors for direct Dark Matter searches

NASA Astrophysics Data System (ADS)

A novel experiment for direct search for Dark Matter with liquid argon double-phase chamber with a mass of liquid Ar up to several hundred tons is proposed. To suppress the ?, ? and n 0 backgrounds, the comparison of scintillation and ionization signals for every event is suggested. The addition in liquid Ar of photosensitive Ge(CH3)4 or C2H4 and suppression of triplet component of scintillation signals ensures the detection of scintillation signals with high efficiency and provides a complete suppression of the electron background. For the detection of photoelectrons and ionization electrons, highly stable and reliable GEM detectors must be used.

Ovchinnikov, B. M.; Ovchinnikov, Yu. B.; Parusov, V. V.

2012-10-01

147

Direct neutralino searches in the NMSSM with gravitino LSP in the degenerate scenario

NASA Astrophysics Data System (ADS)

In the present work a two-component dark matter model is studied adopting the degenerate scenario in the R-parity conserving NMSSM. The gravitino LSP and the neutralino NLSP are extremely degenerate in mass, avoiding the BBN bounds and obtaining a high reheating temperature for thermal leptogenesis. In this model both gravitino (absolutely stable) and neutralino (quasi-stable) contribute to dark matter, and direct detection searches for neutralino are discussed. Points that survive all the constraints correspond to a singlino-like neutralino.

Panotopoulos, Grigoris

2011-12-01

148

Direct neutralino searches in the NMSSM with gravitino LSP in the degenerate scenario

NASA Astrophysics Data System (ADS)

In the present work a two-component dark matter model is studied adopting the degenerate scenario in the R-parity conserving NMSSM. The gravitino LSP and the neutralino NLSP are extremely degenerate in mass, avoiding the BBN bounds and obtaining a high reheating temperature for thermal leptogenesis. In this model both gravitino (absolutely stable) and neutralino (quasi-stable) contribute to dark matter, and direct detection searches for neutralino are discussed. Points that survive all the constraints correspond to a singlino-like neutralino.

Barenboim, Gabriela; Panotopoulos, Grigoris

2011-08-01

149

In 2004, a professional delegation of multicultural educators visited the People's Republic of China to explore how diversity issues are addressed and how students are prepared for entry into the international workforce. The delegation, sponsored by the People to People Ambassador Programs, observed numerous parallels to the American system of education, including the challenge of providing equity for students of

Jioanna Carjuzaa; J. Kay Fenimore-Smith; Ethlyn Davis Fuller; William A. Howe; Eileen Kugler; Ivette Ruiz; Barbara Shin

2008-01-01

150

ERIC Educational Resources Information Center

|In 2004, a professional delegation of multicultural educators visited the People's Republic of China to explore how diversity issues are addressed and how students are prepared for entry into the international workforce. The delegation, sponsored by the People to People Ambassador Programs, observed numerous parallels to the American system of…

Carjuzaa, Jioanna; Fenimore-Smith, J. Kay; Fuller, Ethlyn Davis; Howe, William A.; Kugler, Eileen; London, Arcenia P.; Ruiz, Ivette; Shin, Barbara

2008-01-01

151

Activity in V4 Reflects the Direction, But Not the Latency, of Saccades During Visual Search

We constantly make eye movements to bring objects of interest onto the fovea for more detailed processing. Activity in area V4, a prestriate visual area, is enhanced at the location corresponding to the target of an eye movement. However, the precise role of activity in V4 in relation to these saccades and the modulation of other cortical areas in the oculomotor system remains unknown. V4 could be a source of visual feature information used to select the eye movement, or alternatively, it could reflect the locus of spatial attention. To test these hypotheses, we trained monkeys on a visual search task in which they were free to move their eyes. We found that activity in area V4 reflected the direction of the upcoming saccade but did not predict the latency of the saccade in contrast to activity in the lateral intraparietal area (LIP). We suggest that the signals in V4, unlike those in LIP, are not directly involved in the generation of the saccade itself but rather are more closely linked to visual perception and attention. Although V4 and LIP have different roles in spatial attention and preparing eye movements, they likely perform complimentary processes during visual search.

Gee, Angela L.; Ipata, Anna E.

2010-01-01

152

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., ?2) for Doppler observations of stars potentially harboring multiple planetary companions (assuming negligible planet–planet interactions). Given the high-dimensionality of

Eric B. Ford

2009-01-01

153

The egg of the direct-developing frog, Eleutherodactylus coqui, has 20 x the volume as that of the model amphibian, Xenopus laevis. Increased egg size led to the origin of nutritional endoderm, a novel cell type that provides nutrition but does not differentiate into digestive tract tissues. As the E. coqui endoderm develops, a distinct boundary exists between differentiating intestinal cells and large yolky cells, which persists even when yolk platelets are depleted. The yolky cells do not become tissues of the digestive tract and are lost, as shown by histology and lineage tracing. EcSox17, an endodermal transcriptional factor, did not distinguish these two cell types, however. When cleavage of the yolky cells was inhibited, embryogenesis continued, indicating that some degree of incomplete cleavage can be tolerated. The presence of cellularized nutritional endoderm in E. coqui may parallel changes that occurred in the evolution of the amniote egg 360 million years ago. PMID:17436277

Buchholz, Daniel R; Singamsetty, Srikanth; Karadge, Uma; Williamson, Sean; Langer, Carrie E; Elinson, Richard P

2007-05-01

154

In this paper, three direct search algorithms, i.e. a modified simplex, random direction search and enhanced Powell’s methods\\u000a together with a new localised response surface method are presented and applied to solve die shape optimisation problems for\\u000a achieving net-shape accuracy in metal forming processes. The main motivation is to develop efficient and easy to implement\\u000a optimisation algorithms in metal forming

Bin Lu; Hengan Ou; Hui Long

155

The training of a Multi-Layer Perceptron (MLP) classifier is considered as a Combinatorial Optimization task and solved using the Reactive Tabu Search (RTS) method. RTS needs only forward passes (no derivatives) and does not require high precision network parameters. TOTEM, a special-purpose VLSI chip, was developed to take advantage of the limited memory and processing requirements of RTS: the final

G. Anzellotti; R. Battiti; I. Lazzizzera; G. Soncini; A. Zorat; A. Sartori; G. Tecchiolli; P. Lee

1995-01-01

156

The authors describe a parallel alternate direction implicit (ADI) algorithm for the solution of the unsteady heat conduction equation discretized with fourth-order accuracy. A novel parallel pentadiagonal line-inversion procedure based on a divide-and-conquer strategy is used in conjunction with a domain-decomposition technique. The algorithm has been implemented on the CM-5 in the MIMD mode, and its performance for varying grid sizes and number of processors is investigated.

Wang, Mingyu; Vanka, S.P. (Univ. of Illinois, Urbana, Champaign, IL (United States))

1993-09-01

157

The authors describe a parallel alternate direction implicit (ADI) algorithm for the solution of the unsteady heat conduction equation discretized with fourth-order accuracy. A novel parallel pentadiagonal line-inversion procedure based on a divide-and-conquer strategy is used in conjunction with a domain-decomposition technique. The algorithm has been implemented on the CM-5 in the MIMD mode, and its performance for varying grid

Mingyu Wang; S. P. Vanka

1993-01-01

158

There is a high demand of space-efficient algorithms in built-in or embedded softwares. In this paper, we consider the problem of designing space-efficient algorithms for computing the maximum area empty rectangle (MER) among a set of points inside a rectangular region $\\\\cal R$ in 2D. We first propose an inplace algorithm for computing the priority search tree with a set

Minati De; Subhas C. Nandy

2011-01-01

159

Probing Scalar Dark Matter with Direct Experimental Searches and the LHC

NASA Astrophysics Data System (ADS)

The standard model (SM) plus a real gauge-singlet scalar field called darkon (SM+D) is the simplest model possessing a weakly interacting massive particle (WIMP) dark-matter candidate. The upper limits for the WIMP-nucleon elastic cross-section as a function of WIMP mass recently set by the direct-search experiments XENON10 and CDMS II rule out darkon mass ranges from 10 to (50, 70, 75) GeV for Higgs-boson masses of (120, 200, 350) GeV, respectively. This may exclude the possibility of the darkon providing an explanation for the gamma-ray excess observed in the EGRET data. It is shown that by extending the SM+D to a two-Higgs-doublet model plus a darkon the experimental constraints on the WIMP-nucleon interactions can be evaded due to suppression occurring in some of the parameter space of the model. Moreover, the darkon model can also be probed in Higgs-boson searches at the CERN Large Hadron Collider (LHC).

Tandean, Jusak

2009-07-01

160

Prospects of dark matter direct search under deep sea water in India

NASA Astrophysics Data System (ADS)

There is compelling evidence from cosmological and astrophysical observations that about one quarter of the energy density of the universe can be attributed to cold dark matter (CDM), whose nature and properties are still unknown. Around the world large numbers of experiments are using different techniques of dark matter direct and indirect detections. According to their experimental requirements location of the experiment prefer to use either underground, under ice, or under sea water. Country like India, digging underground cavern and long tunnel is not very convenient. Therefore, authors look from the either solutions of this problem preferring to use deep sea water. In this article, we discuss the pros and corns of use of deep sea water in the dark matter search.

Singh, V.; Subrahmanyam, V. S.; Singh, L.; Singh, M. K.; Sharma, V.; Chouhan, N. S.; Jaiswal, M. K.; Soma, A. K.

2013-04-01

161

Optimization of a binary filter by direct binary search algorithm for rotation-invariant JTC

NASA Astrophysics Data System (ADS)

An optimum training process using a direct binary search algorithm for synthesising a spatial domain binary filter to implement in the joint transform correlator (JTC) architecture is presented. The major advantage of the proposed filter are rotation invariance, higher discriminability for similar targets, and convenience for optical implementation in the JTC using a Ferroelectric over silicon SLM as a binary phase modulator. Results of the invariant filter are presented for classical JTC, DC free JTC using phase shifting technique, and for the binarised JTC by applying edge-enhancement and mean thresholding at the JPS. Testing so far, shows that binary filter is able to distinguish between target and anti-target images for all these cases.

Butt, J. A.; Wilkinson, T. D.; Crossland, W. A.

2003-11-01

162

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

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

163

NASA Astrophysics Data System (ADS)

We present a three-dimensional fully dynamic parallel particle-based model for direct pore-level simulation of incompressible viscous fluid flow in disordered porous media. The model was developed from scratch and is capable of simulating flow directly in three-dimensional high-resolution microtomography images of naturally occurring or man-made porous systems. It reads the images as input where the position of the solid walls are given. The entire medium, i.e., solid and fluid, is then discretized using particles. The model is based on Moving Particle Semi-implicit (MPS) technique. We modify this technique in order to improve its stability. The model handles highly irregular fluid-solid boundaries effectively. It takes into account viscous pressure drop in addition to the gravity forces. It conserves mass and can automatically detect any false connectivity with fluid particles in the neighboring pores and throats. It includes a sophisticated algorithm to automatically split and merge particles to maintain hydraulic connectivity of extremely narrow conduits. Furthermore, it uses novel methods to handle particle inconsistencies and open boundaries. To handle the computational load, we present a fully parallel version of the model that runs on distributed memory computer clusters and exhibits excellent scalability. The model is used to simulate unsteady-state flow problems under different conditions starting from straight noncircular capillary tubes with different cross-sectional shapes, i.e., circular/elliptical, square/rectangular and triangular cross-sections. We compare the predicted dimensionless hydraulic conductances with the data available in the literature and observe an excellent agreement. We then test the scalability of our parallel model with two samples of an artificial sandstone, samples A and B, with different volumes and different distributions (non-uniform and uniform) of solid particles among the processors. An excellent linear scalability is obtained for sample B that has more uniform distribution of solid particles leading to a superior load balancing. The model is then used to simulate fluid flow directly in REV size three-dimensional x-ray images of a naturally occurring sandstone. We analyze the quality and consistency of the predicted flow behavior and calculate absolute permeability, which compares well with the available network modeling and Lattice-Boltzmann permeabilities available in the literature for the same sandstone. We show that the model conserves mass very well and is stable computationally even at very narrow fluid conduits. The transient- and the steady-state fluid flow patterns are presented as well as the steady-state flow rates to compute absolute permeability. Furthermore, we discuss the vital role of our adaptive particle resolution scheme in preserving the original pore connectivity of the samples and their narrow channels through splitting and merging of fluid particles.

Ovaysi, S.; Piri, M.

2009-12-01

164

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

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

165

Influence of data volume and EPC on process window in massively parallel e-beam direct write

NASA Astrophysics Data System (ADS)

Multiple e-beam direct write lithography (MEBDW), using >10,000 e-beams writing in parallel, proposed by MAPPER, KLA-Tencor, and IMS is a potential solution for 20-nm half-pitch and beyond. The raster scan in MEBDW makes bitmap its data format. Data handling becomes indispensable since bitmap needs a huge data volume due to the fine pixel size to keep the CD accuracy after e-beam proximity correction (EPC). In fact, in 10,000-beam MEBDW, for a 10 WPH tool of 1-nm pixel size and 1-bit gray level, the aggregated data transmission rate would be up to 1963 Tera bits per second (bps), requiring 19,630 fibers transmitting 10 Gbps in each fiber. The data rate per beam would be <20 Gbps. Hence data reduction using bigger pixel size, fewer grey levels to achieve sub-nm EPC accuracy, and data truncation have been extensively studied. In this paper, process window assessment through Exposure-Defocus (E-D) Forest to quantitatively characterize the data truncation before and after EPC is reported. REBL electron optics, electron scattering in resist, and resist acid diffusion are considered, to construct the E-D Forest and to analyze the imaging performance of the most representative layers and patterns, such as critical line/space and hole layers with minimum pitch, cutting layers, and implant layers, for the 10-nm, and 7-nm nodes.

Lin, Shy-Jay; Liu, Pei-Yi; Chen, Cheng-Hung; Wang, Wen-Chuan; Shin, Jaw-Jung; Lin, Burn Jeng; McCord, Mark A.; Shriyan, Sameet K.

2013-03-01

166

Cost function analysis for stochastic clustered-dot halftoning based on direct binary search

NASA Astrophysics Data System (ADS)

Most electrophotographic printers use periodic, clustered-dot screening for rendering smooth and stable prints. However, periodic, clustered-dot screening suffers from the problem of periodic moirÂ´e resulting from interference between the component periodic screens superposed for color printing. There has been proposed an approach, called CLU-DBS for stochastic, clustered-dot halftoning and screen design based on direct binary search. This method deviates from conventional DBS in its use of different filters in different phases of the algorithm. In this paper, we derive a closed-form expression for the cost metric which is minimized in CLU-DBS. The closed-form expression provides us with a clearer insight on the relationship between input parameters and processes, and the output texture, thus enabling us generate better quality texture. One of the limitations of the CLU-DBS algorithm proposed earlier is the inversion in the distribution of clusters and voids in the final halftone with respect to the initial halftone. In this paper, we also present a technique for avoiding the inversion by negating the sign of one of the error terms in the newly derived cost metric, which is responsible for clustering. This not only simplifies the CLU-DBS screen design process, but also significantly reduces the number of iterations required for optimization.

Goyal, Puneet; Gupta, Madhur; Staelin, Carl; Fischer, Mani; Shacham, Omri; Allebach, Jan

2011-01-01

167

R&D Status of Nuclear Emulsion for Directional Dark Matter Search

NASA Astrophysics Data System (ADS)

In this study, we are doing R&D for directional dark matter search with nuclear emulsion. First of all, higher resolution nuclear emulsion with fine silver halide crystals was developed in the production facility of emulsion at Nagoya university, and we confirmed that it can detect the expected nuclear recoil tracks. The readout of submicron tracks was required the new technology. We developed the expansion technique, and could readout the signal by shape analysis with optical microscopy. The two dimensional angular resolution is 36 degrees at the original track length of range from 150 nm to 200 nm with optical microscopy. Finally we demonstrated by using recoiled nuclei induced by 14.8 MeV neutron, and confirmed the technique. Moreover, we developed the X-ray microscope system with SPring-8 as final check with higher resolution of selected candidate tracks with optical microscopy. The angular resolution was improved from 31 degree with optical microscopy to 17 degree with X-ray microscopy at the track length of range from 150 nm to 250 nm. We are developing the practical system and planning for start of the test running with prototype detector.

Naka, T.; Kimura, M.; Nakamura, M.; Sato, O.; Nakano, T.; Asada, T.; Tawara, Y.; Suzuki, Y.

2012-02-01

168

In a recent paper, we have published a new algorithm, designated ‘iCycle’, for fully automated multi-criterial optimization of beam angles and intensity profiles. In this study, we have used this algorithm to investigate the relationship between plan quality and the extent of the beam direction search space, i.e. the set of candidate beam directions that may be selected for generating

Linda Rossi; Sebastiaan Breedveld; Ben J M Heijmen; Peter W J Voet; Nico Lanconelli; Shafak Aluwini

2012-01-01

169

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

170

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

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) in Hong

Siu-Man Raymond Ting

2007-01-01

171

ERIC Educational Resources Information Center

|The study used the Self-Directed Search (SDS) and the NEO-FFI to explore profile elevation, four secondary constructs, and the Big Five personality factors in a sample of college students in a career course. Regression model results showed that openness, conscientiousness, differentiation high-low, differentiation Iachan, and consistency…

Bullock, Emily E.; Reardon, Robert C.

2008-01-01

172

ERIC Educational Resources Information Center

|Few career counseling theories have had the long-standing background of Hollands RIASEC theory. His theory, which espouses that job satisfaction increases when there is congruence between individuals interests and environments, has resulted in many practical, reliable, and valid inventories, such as the Self-Directed Search (SDS). The majority of…

Osborn, Debra S.

173

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

174

ERIC Educational Resources Information Center

|A comparison of Self-Scoring Error Rate for Self Directed Search (SDS) and the revised SDS is presented. The subjects were college freshmen and sophomores who participated in career planning as a part of their orientation program, and a career workshop. Subjects, N=190 on first study and N=84 on second study, were then randomly assigned to the…

Price, Gary E.; And Others

175

NASA Astrophysics Data System (ADS)

The problem at hand is developing a controller design methodology that is generally applicable to autonomous systems with fairly accurate models. The controller design process has two parts: synthesis and analysis. Over the years, many synthesis and analysis methods have been proposed. An optimal method for all applications has not yet been found. Recent advances in computer technology have made computational methods more attractive and practical. The proposed method is an iterative computational method that automatically generates non-linear controllers with specified global performance. This dissertation describes this method which consists of using an analysis tool, continued propagation cell mapping (CPCM), as feedback to the synthesis tool, best estimate directed search (BEDS). Optimality in the design can be achieved with respect to time, energy, and/or robustness depending on the performance measure used. BEDS is based on a novel search concept: globally directing a random search. BEDS has the best of two approaches: gradient (or directed) search and random search. It possesses the convergence speed of a gradient search and the convergence robustness of a random search. The coefficients of the best controller at the time direct the search process until either a better controller is found or the search is terminated. CPCM is a modification of simple cell mapping (SCM). CPCM maintains the simplicity of SCM but provides accuracy near that of a point map (PM). CPCM evaluates the controller's complete and global performance efficiently and with easily tunable accuracy. This CPCM evaluation guarantees monotonic progress in the synthesis process. The method is successfully applied to the design of a TSK-type fuzzy logic (FL) controller and a Sliding Mode-type controller for the uncertain non-linear system of an inverted pendulum on a cart for large pole angles (+/-86 degrees). The resulting controller's performance compares favorably to other established methods designed with dynamic programing (DP) and genetic algorithms (GA). When CPCM is used as feedback to BEDS, the resulting design method quickly and automatically generates non-linear controllers with good global performance and without much a priori information about the desired control actions.

Rizk, Charbel George

1997-11-01

176

PARALLEL METAHEURISTICS FOR COMBINATORIAL OPTIMIZATION

In this paper, we review parallel metaheuristics for approximating the global optimal solution of combinatorial optimization problems. Recent developments on parallel implementation of genetic algorithms, simulated an- nealing, tabu search, variable neighborhood search, and greedy randomized adaptive search procedures (GRASP) are discussed.

MAURICIO G. C. RESENDE; PANOS M. PARDALOS; SANDRA DUNI

1999-01-01

177

PARALLEL STRINGS - PARALLEL UNIVERSES

Sometimes different parts of the battery community just don't seem to operate on the same level, and attitudes towards parallel battery strings are a prime example of this. Engineers at telephone company central offices are quite happy operating 20 or more parallel strings on the same dc bus, while many manufacturers warn against connecting more than four or five strings

Jim McDowall; Saft America

178

Global steering of single gimballed control moment gyroscopes using a directed search

A guided depth-first search that manages null motion about torque-producing trajectories calculated with a singularity-robust inverse is proposed as a practical feedforward steering law that can globally avoid (or minimize the impact of) singular states in minimally-redundant systems of single gimballed control moment gyroscopes. Cost and heuristic functions are defined to guide the search procedure in improving gimbal trajectories. On-orbit

Joseph A. Paradiso

1992-01-01

179

We consider the solution of nonlinear programs in the case where derivatives of the objective function and nonlinear constraints are unavailable. To solve such problems, we propose an adaptation of a method due to Conn, Gould, Sartenaer, and Toint that proceeds by approximately minimizing a succession of linearly constrained augmented Lagrangians. Our modification is to use a derivative-free generating set direct search algorithm to solve the linearly constrained subproblems. The stopping criterion proposed by Conn, Gould, Sartenaer and Toint for the approximate solution of the subproblems requires explicit knowledge of derivatives. Such information is presumed absent in the generating set search method we employ. Instead, we show that stationarity results for linearly constrained generating set search methods provide a derivative-free stopping criterion, based on a step-length control parameter, that is sufficient to preserve the convergence properties of the original augmented Lagrangian algorithm.

Lewis, Robert Michael (College of William and Mary, Williamsburg, VA); Torczon, Virginia Joanne (College of William and Mary, Williamsburg, VA); Kolda, Tamara Gibson

2006-08-01

180

In a recent paper, we have published a new algorithm, designated 'iCycle', for fully automated multi-criterial optimization of beam angles and intensity profiles. In this study, we have used this algorithm to investigate the relationship between plan quality and the extent of the beam direction search space, i.e. the set of candidate beam directions that may be selected for generating an optimal plan. For a group of ten prostate cancer patients, optimal IMRT plans were made for stereotactic body radiation therapy (SBRT), mimicking high dose rate brachytherapy dosimetry. Plans were generated for five different beam direction input sets: a coplanar (CP) set and four non-coplanar (NCP) sets. For CP treatments, the search space consisted of 72 orientations (5° separations). The NCP CyberKnife (CK) space contained all directions available in the robotic CK treatment unit. The fully non-coplanar (F-NCP) set facilitated the highest possible degree of freedom in selecting optimal directions. CK(+) and CK(++) were subsets of F-NCP to investigate some aspects of the CK space. For each input set, plans were generated with up to 30 selected beam directions. Generated plans were clinically acceptable, according to an assessment of our clinicians. Convergence in plan quality occurred only after around 20 included beams. For individual patients, variations in PTV dose delivery between the five generated plans were minimal, as aimed for (average spread in V(95): 0.4%). This allowed plan comparisons based on organ at risk (OAR) doses, with the rectum considered most important. Plans generated with the NCP search spaces had improved OAR sparing compared to the CP search space, especially for the rectum. OAR sparing was best with the F-NCP, with reductions in rectum D(Mean), V(40Gy), V(60Gy) and D(2%) compared to CP of 25%, 35%, 37% and 8%, respectively. Reduced rectum sparing with the CK search space compared to F-NCP could be largely compensated by expanding CK with beams with relatively large direction components along the superior-inferior axis (CK(++)). Addition of posterior beams (CK(++) ? F-NCP) did not lead to further improvements in OAR sparing. Plans with 25 beams clearly performed better than 11-beam plans. For CP plans, an increase from 11 to 25 involved beams resulted in reductions in rectum D(Mean), V(40Gy), V(60Gy) and D(2%) of 39%, 57%, 64% and 13%, respectively. PMID:22864234

Rossi, Linda; Breedveld, Sebastiaan; Heijmen, Ben J M; Voet, Peter W J; Lanconelli, Nico; Aluwini, Shafak

2012-08-03

181

NASA Astrophysics Data System (ADS)

In a recent paper, we have published a new algorithm, designated ‘iCycle’, for fully automated multi-criterial optimization of beam angles and intensity profiles. In this study, we have used this algorithm to investigate the relationship between plan quality and the extent of the beam direction search space, i.e. the set of candidate beam directions that may be selected for generating an optimal plan. For a group of ten prostate cancer patients, optimal IMRT plans were made for stereotactic body radiation therapy (SBRT), mimicking high dose rate brachytherapy dosimetry. Plans were generated for five different beam direction input sets: a coplanar (CP) set and four non-coplanar (NCP) sets. For CP treatments, the search space consisted of 72 orientations (5° separations). The NCP CyberKnife (CK) space contained all directions available in the robotic CK treatment unit. The fully non-coplanar (F-NCP) set facilitated the highest possible degree of freedom in selecting optimal directions. CK+ and CK++ were subsets of F-NCP to investigate some aspects of the CK space. For each input set, plans were generated with up to 30 selected beam directions. Generated plans were clinically acceptable, according to an assessment of our clinicians. Convergence in plan quality occurred only after around 20 included beams. For individual patients, variations in PTV dose delivery between the five generated plans were minimal, as aimed for (average spread in V95: 0.4%). This allowed plan comparisons based on organ at risk (OAR) doses, with the rectum considered most important. Plans generated with the NCP search spaces had improved OAR sparing compared to the CP search space, especially for the rectum. OAR sparing was best with the F-NCP, with reductions in rectum DMean, V40Gy, V60Gy and D2% compared to CP of 25%, 35%, 37% and 8%, respectively. Reduced rectum sparing with the CK search space compared to F-NCP could be largely compensated by expanding CK with beams with relatively large direction components along the superior-inferior axis (CK++). Addition of posterior beams (CK++ ? F-NCP) did not lead to further improvements in OAR sparing. Plans with 25 beams clearly performed better than 11-beam plans. For CP plans, an increase from 11 to 25 involved beams resulted in reductions in rectum DMean, V40Gy, V60Gy and D2% of 39%, 57%, 64% and 13%, respectively.

Rossi, Linda; Breedveld, Sebastiaan; Heijmen, Ben J. M.; Voet, Peter W. J.; Lanconelli, Nico; Aluwini, Shafak

2012-09-01

182

NASA Astrophysics Data System (ADS)

A robust signal for sidereal anisotropy in nuclear recoils would support, perhaps more decisively than any other evidence, a discovery claim for a WIMP component of Dark Matter. I present a concept based on columnar recombination in dense xenon gas, sensing nuclear recoil direction relative to a TPC drift field. The central advance is that nuclear recoil directionality information is obtained through a comparison, event-by-event, of the ionization signal and recombination signal that are produced prior to drifting the track ionization. The optimum xenon density for this concept may be near ten bars, unlike conventional techniques that employ track visualization - with severe restrictions on gas density to about 1/10 bar. No restriction is imposed by diffusion during drift, facilitating the realization of a large monolithic room temperature xenon gas Time Projection Chamber at the ton-scale, with unprecedented sensitivity for both directionality and cross-section. Remarkably, the desired operating conditions for 0-??? 136Xe experiment may be identical.

Nygren, D. R.

2013-10-01

183

NASA Astrophysics Data System (ADS)

This paper presents an improved direct binary search (DBS)-based algorithm for generating holograms to holographic optical tweezers. The simulations show that the improved algorithm greatly enhances computation speed while maintaining high hologram efficiency and high-intensity homogeneous target spots. The improved algorithm was applied to generate holographic optical tweezers in several experiments. The experiments demonstrate that real-time trap and manipulation can be realized with the improved algorithm if the number of trapped microparticles is small.

Zhao, Xudong; Li, Jing; Tao, Tao; Long, Qian; Wu, Xiaoping

2012-01-01

184

This investigation explored the use of Holland's Self-Directed Search (SDS) by non-readers with learning disabilities and non-readers with mild mental retardation. A total of 43 middle and high school special education teachers were instructed in the administration of the SDS to both readers and non-readers with learning disabilities and mild mental retardation (n = 337) . Results show that, for

Harold D. Mattie

2000-01-01

185

Analysis of the laminar flow of a non-Newtonian fluid between rotating parallel planes permits the viscosity to be calculated as a function of shear rate from data of torque vs angular velocity. Experimental results are presented which show that the non-Newtonian viscosities thus obtained agree with capillary, Couette, and cone-and-plate instruments over a four-decade shear rate range.

Irvin M. Krieger; Martin E. Woods

1966-01-01

186

This paper presents a maximum power point tracking approach for a photovoltaic system using the dividing rectangles algorithm. The new approach overcomes some weaknesses of the existing methods such as the perturb and observe method as it is capable of searching for global maximum. This is particularly important for a system that is partially shaded. To validate the performance of

Tat Luat Nguyen; Kay-Soon Low

2010-01-01

187

Tools of the Trade. A Self Directed Job Search Program. Final Report.

ERIC Educational Resources Information Center

|The Tools of the Trade project was undertaken to offer comprehensive job search assistance to adult basic education students in the form of career awareness workshops. The workshops covered the following topics: completing job applications, writing resumes, filling out skill cards, interviewing for a job, analyzing the job market, following up on…

Molek, Carol

188

A Search for Institutional Distinctiveness. New Directions for Community Colleges, Number 65.

ERIC Educational Resources Information Center

|The essays in this collection argue that community colleges have much to gain by seeking out and maintaining positive recognition of the features that distinguish them from other colleges in the region and state. In addition, the sourcebook contains articles discussing the process of conducting a search for institutional distinctiveness and ways…

Townsend, Barbara K., Ed.

1989-01-01

189

Search for Direct Band Gap in Group IV Semiconductor Alloys and Quantum Wire Structures

Interest in creating direct band gap group IV, semiconductor, particularly silicon based structures, has been stimulated with the discovery of the photoluminescence in electrochemically etched porous silicon. This work examines, theoretically, the possibilities of the existence of a direct band gap in group IV alloys and quantum wire structures using empirical pseudopotential method (EPM) for the calculation of the energy

Khalid Mahmood

1994-01-01

190

Specification of the dorsal axis in commonly studied frogs, such as Xenopus laevis and Rana pipiens, depends on a microtubule-mediated movement of cytoplasm in the fertilized egg. The Puerto Rican tree frog, Eleutherodactylus coqui, has an egg that is twenty times the volume of that of X. laevis, raising the question as to whether the mechanism of dorsal axial specification is conserved in these large eggs. Fertilized eggs of E. coqui develop a transient array of parallel microtubules, similar to other frogs, but proportionately larger. The array persists after first cleavage, longer than in other frogs, and is gone by the third cleavage. Correlated with the longer life of the parallel microtubules, both 2- and 8-cell E. coqui embryos remain sensitive to gravity-mediated axial specification, a sensitivity lost in X. laevis before the 2-cell stage. Activation of the Wnt/beta-catenin pathway by injected Xwnt8 RNA causes axial formation as in X. laevis. The results indicate that elements of dorsal axial specification are conserved in E. coqui, but they occur later compared to in X. laevis. PMID:12590350

Elinson, Richard P; Ninomiya, Hiromasa

2002-12-13

191

NASA Astrophysics Data System (ADS)

The direct numerical simulation (DNS) offers the most accurate approach to modeling the behavior of a physical system, but carries an enormous computation cost. There exists a need for an accurate DNS to model the coupled solid-fluid system seen in targeted drug delivery (TDD), nanofluid thermal energy storage (TES), as well as other fields where experiments are necessary, but experiment design may be costly. A parallel DNS can greatly reduce the large computation times required, while providing the same results and functionality of the serial counterpart. A D2Q9 lattice Boltzmann method approach was implemented to solve the fluid phase. The use of domain decomposition with message passing interface (MPI) parallelism resulted in an algorithm that exhibits super-linear scaling in testing, which may be attributed to the caching effect. Decreased performance on a per-node basis for a fixed number of processes confirms this observation. A multiscale approach was implemented to model the behavior of nanoparticles submerged in a viscous fluid, and used to examine the mechanisms that promote or inhibit clustering. Parallelization of this model using a masterworker algorithm with MPI gives less-than-linear speedup for a fixed number of particles and varying number of processes. This is due to the inherent inefficiency of the master-worker approach. Lastly, these separate simulations are combined, and two-way coupling is implemented between the solid and fluid.

Sloan, Gregory James

192

Workforce planning with parallel algorithms

Workforce planning is an important activity that en- ables organizations to determine the workforce needed for continued success. A workforce planning problem is a very complex task that requires modern techniques to be solved adequately. In this work, we describe the development of two parallel metaheuristic methods, a parallel genetic algorithm and a parallel scatter search, which can find high-quality

Enrique Alba; Gabriel Luque; Francisco Luna

2006-01-01

193

Parallel Processing of Discrete Optimization Problems

Discrete optimization problems (DOPs) arise in various applications such as planning,scheduling, computer aided design, robotics, game playing and constraint directed reasoning.Often, a DOP is formulated in terms of finding a (minimum cost) solution path in agraph from an initial node to a goal node and solved by graph\\/tree search methods suchas branch-and-bound and dynamic programming. Availability of parallel computers hascreated

Grama Y. Ananth; Vipin Kumar; Panos Pardalos

1992-01-01

194

Tools for model-independent bounds in direct dark matter searches

NASA Astrophysics Data System (ADS)

We discuss a framework (based on non-relativistic operators) and a self-contained set of numerical tools to derive the bounds from some current direct detection experiments on virtually any arbitrary model of Dark Matter elastically scattering on nuclei.

Cirelli, Marco; Del Nobile, Eugenio; Panci, Paolo

2013-10-01

195

Status and Future Directions of Online Search Services in Georgia Academic Libraries.

ERIC Educational Resources Information Center

|This study evolved from a survey of all academic libraries in Georgia, designed to identify current online activities in the state's academic libraries, and to predict future directions and trends. The information was gathered to provide a pool of data for comparison, planning, management, and administration of online services, and to serve as a…

Mosby, Anne Page; McKinney, Gayle

196

If countries compete for capital in the shape of foreign direct investment (FDI), from the point of view of multinational enterprises (MNEs), there is a market for the social order on offer in different nation states. MNEs seek out particular models of social order for their FDI projects. In the middle is a diverse set of organisations who mediate between

N. A. Phelps; F. Wub

2009-01-01

197

A Search for New Directions in the War Against Poverty. Staff Paper.

ERIC Educational Resources Information Center

Demographic surveys and data could be used to assess programs and policies directly and indirectly concerned with the reduction of poverty, and, through the use of such survey data, to point to a number of population subgroupings which are or are not moving out of poverty. Annually collected Census Bureau facts, the basis of much of the analysis…

Sheppard, Harold L.

198

Status and Future Directions of Online Search Services in Georgia Academic Libraries.

ERIC Educational Resources Information Center

This study evolved from a survey of all academic libraries in Georgia, designed to identify current online activities in the state's academic libraries, and to predict future directions and trends. The information was gathered to provide a pool of data for comparison, planning, management, and administration of online services, and to serve as a…

Mosby, Anne Page; McKinney, Gayle

199

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

200

We present the results of an analysis of data recorded at the Pierre Auger Observatory in which we search for groups of directionally-aligned events (or ''multiplets'') which exhibit a correlation between arrival direction and the inverse of the energy. These signatures are expected from sets of events coming from the same source after having been deflected by intervening coherent magnetic fields. The observation of several events from the same source would open the possibility to accurately reconstruct the position of the source and also measure the integral of the component of the magnetic field orthogonal to the trajectory of the cosmic rays. We describe the largest multiplets found and compute the probability that they appeared by chance from an isotropic distribution. We find no statistically significant evidence for the presence of multiplets arising from magnetic deflections in the present data.

Abreu, P.; /Lisbon, IST; Aglietta, M.; /Turin U. /INFN, Turin; Ahn, E.J.; /Fermilab; Albuquerque, I.F.M.; /Sao Paulo U.; Allard, D.; /APC, Paris; Allekotte, I.; /Buenos Aires, CONICET; Allen, J.; /New York U.; Allison, P.; /Ohio State U.; Alvarez Castillo, J.; /Mexico U., ICN; Alvarez-Muniz, J.; /Santiago de Compostela U.; Ambrosio, M.; /Naples U. /INFN, Naples /Nijmegen U., IMAPP

2011-11-01

201

NASA Astrophysics Data System (ADS)

We present the results of an analysis of data recorded at the Pierre Auger Observatory in which we search for groups of directionally-aligned events (or 'multiplets') which exhibit a correlation between arrival direction and the inverse of the energy. These signatures are expected from sets of events coming from the same source after having been deflected by intervening coherent magnetic fields. The observation of several events from the same source would open the possibility to accurately reconstruct the position of the source and also measure the integral of the component of the magnetic field orthogonal to the trajectory of the cosmic rays. We describe the largest multiplets found and compute the probability that they appeared by chance from an isotropic distribution. We find no statistically significant evidence for the presence of multiplets arising from magnetic deflections in the present data.

Pierre Auger Collaboration; Abreu, P.; Aglietta, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Anti?i?, T.; Anzalone, A.; Aramo, C.; Arganda, E.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Bäcker, T.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Barroso, S. L. C.; Baughman, B.; Bäuml, J.; Beatty, J. J.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; Benzvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Bohá?ová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Caballero-Mora, K. S.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chudoba, J.; Clay, R. W.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Domenico, M.; de Donato, C.; de Jong, S. J.; de La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; de Mitri, I.; de Souza, V.; de Vries, K. D.; Decerprit, G.; Del Peral, L.; Del Río, M.; Deligny, O.; Dembinski, H.; Dhital, N.; di Giulio, C.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; Dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Fajardo Tapia, I.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Ferrero, A.; Fick, B.; Filevich, A.; Filip?i?, A.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Gascon, A.; Gemmeke, H.; Gesterling, K.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gonçalves, P.; Gonzalez, D.; Gonzalez, J. G.; Gookin, B.; Góra, D.; Gorgi, A.; Gouffon, P.; Gozzini, S. R.; Grashorn, E.; Grebe, S.; Griffith, N.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Guzman, A.; Hague, J. D.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horneffer, A.; Hrabovský, M.; Huege, T.; Insolia, A.; Ionita, F.; Italiano, A.; Jarne, C.; Jiraskova, S.; Josebachuili, M.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuehn, F.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; Lachaud, C.; Lautridou, P.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Lemiere, A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Mertsch, P.; Meurer, C.; Mi?anovi?, S.; Micheletti, M. I.; Miller, W.; Miramonti, L.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Morris, C.; Mostafá, M.; Moura, C. A.; Mueller, S.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niemietz, L.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Oliva, P.; Olmos-Gilbaja, V. M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parra, A.; Parsons, R. D.; Pastor, S.; Paul, T.; Pech, M.; Pe?ala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.; Petrovic, J.; Pfendner, C.

2012-01-01

202

Higgs Boson Particle Search Through Direct Production from Carbon Targets Using - KAON+ Interactions

NASA Astrophysics Data System (ADS)

This dissertation will present methods used and results obtained in one variant of the H particle program on the D6 beam line of the Alternating Gradient Synchrotron (AGS) at the Brookhaven National Laboratories (BNL). The variant presented uses solid ^{12}C and CH_2 targets to study the direct H production reaction from carbon: ^{12}C(K^-, K^+)H, X by analyzing the outgoing K^+ and comparing it with the K^+^ectrum of known reactions of both free and quasi-free Xi^- production reactions p(K^-, K^+)Xi^ -, and ^{12}C(K^ -, K^+)Xi^-, Y. Free Xi^- production has been examined thoroughly and allows us to determine the resolution of our experiment. Quasi-free Xi^- production from ^ {12}C and direct H production from emulsion nuclei have been studied at KEK. The K^+ from H production are expected to be more energetic than those from quasi-free Xi^-. Identification of these high momentum K^+ is the signature sought for H production. Direct H production upper limits are quoted in fractions of the quasi-free Xi^- production to minimize theoretical uncertainties. The 90% upper limit of direct H production from ^ {12}C is observed to be (0.2-0.4)% of quasi-free Xi^- production for an H width of around 31 MeV/c^2, which corresponds to a 50 MeV/c spread in momenta of the associated K^+, for an H mass in the range of 1.85-2.19 GeV/c^2. The limits are near the theoretical estimate of the process for complex nuclei of emulsion: (0.4-0.6)%.

Sukaton, Irianto Rouli

1995-01-01

203

I\\/O-Efficient Strong Connectivity and Depth-First Search for Directed Planar Graphs

We present the first I\\/O-efficient algorithms for the fol- lowing fundamental problems on directed planar graphs: finding the strongly connected components, finding a simple-path 2 3 -separator, and computing a depth-first span- ning (DFS) tree. Our algorithms for the first two prob- lems perform O(sort(N)) I\\/Os, where N = V + E and sort(N) = ?((N\\/B) logM\\/B(N\\/B)) is the number

Lars Arge; Norbert Zeh

2003-01-01

204

Higgs Boson Particle Search Through Direct Production from Carbon Targets Using - KAON+ Interactions

This dissertation will present methods used and results obtained in one variant of the H particle program on the D6 beam line of the Alternating Gradient Synchrotron (AGS) at the Brookhaven National Laboratories (BNL). The variant presented uses solid ^{12}C and CH_2 targets to study the direct H production reaction from carbon: ^{12}C(K^-, K^+)H, X by analyzing the outgoing K^+

Irianto Rouli Sukaton

1995-01-01

205

A simulation-based directed-search method for test generation

This thesis presents a new approach to test generation. The basic concept is as follows: we start with any input vector and simulate the circuit. From the simulation result, a cost function is computed to determine how different this vector is from being a test. The cost is defined in such a way that it will be below a threshold only if the simulated vector is a test. If the vector is not a test, i.e., the cost is high, cost reduction by gradual changes in the vector leads to a test. Two test generation programs, TVSET and CONTEST, were implemented. TVSET uses anew modeling and simulation technique, called Threshold-Value Simulation, that can perform logic simulation and simultaneously compute dynamic testability measures to guide the search for tests. CONTEST extends the well-known concurrent fault simulation method for test generation. Using suitable cost functions, CONTEST has been able to generate: (1) initialization sequences, (2) tests for a group of faults, and (3) a test for a given fault. A simple cost function is the distance (in terms of the number of gates and flip-flops) of a fault effect from a primary output. Preliminary implementations of both algorithms have shown the potential for superior performance compared to existing sequential test generators.

Cheng, K.T.

1988-01-01

206

Parallel Metaheuristics for Workforce Planning

Workforce planning is an important activity that enables organizations to determine the workforce needed for continued success.\\u000a A workforce planning problem is a very complex task requiring modern techniques to be solved adequately. In this work, we\\u000a describe the development of three parallel metaheuristic methods, a parallel genetic algorithm, a parallel scatter search,\\u000a and a parallel hybrid genetic algorithm, which

Enrique Alba; Gabriel Luque; Francisco Luna

2007-01-01

207

Impact of dark matter direct searches and the LHC analyses on branon phenomenology

Dark Matter direct detection experiments are able to exclude interesting parameter space regions of particle models which predict an important amount of thermal relics. We use recent data to constrain the branon model and to compute the region that is favored by CDMS measurements. Within this work, we also update present colliders constraints with new studies coming from the LHC. Despite the present low luminosity, it is remarkable that for heavy branons, CMS and ATLAS measurements are already more constraining than previous analyses performed with TEVATRON and LEP data.

Cembranos, Jose A. R. [Departamento de Fisica Teorica I, Universidad Complutense de Madrid, E-28040 (Spain); Diaz-Cruz, J. Lorenzo; Prado, Lilian [Facultad de Ciencias Fisico-Matematicas, Benemerita Universidad Autonoma de Puebla, C. P. 72570, Puebla, Pue. (Mexico)

2011-10-15

208

Complementarity between direct and indirect searches of Dark Matter and the ILC

We study the possibility of identifying dark matter properties from XENON-like 100 kg experiments and the GLAST satellite mission. We show that whereas direct detection experiments will probe efficiently light WIMPs, given a positive detection (at the 10% level for m{sub {chi}} < or approx. 50 GeV), GLAST will be able to confirm and even increase the precision in the case of a NFW profile, for a WIMP-nucleon cross-section {sigma}{sub {chi}}{sub -p} < or approx. 10{sup -8} pb. We also predict the production rate of a WIMP in the next generation of colliders (ILC), and compare their sensitivity to the WIMP mass with the XENON and GLAST projects.

Mambrini, Yann [Laboratoire de Physique Theorique, Universite Paris-Sud, F-91405 Orsay (France)

2009-04-17

209

Predicted Modulated Differential Rates for Direct WIMP Searches at Low Energy Transfers

NASA Astrophysics Data System (ADS)

The differential event rate for direct detection of dark matter, both the time averaged and the modulated one due to the motion of the Earth, are discussed. The calculations focus on relatively light cold dark matter candidates (WIMP) and low energy transfers. It is shown that for sufficiently light WIMPs the extraction of relatively large nucleon cross sections is possible. Furthermore for some WIMP masses the modulation amplitude may change sign, meaning that, in such a case, the maximum rate may occur six months later than naively expected. This effect can be exploited to yield information about the mass of the dark matter candidate, if and when the observation of the modulation of the event rate is established.

J. D., Vergados

2012-03-01

210

Global interpretation of direct Dark Matter searches after CDMS-II results

We perform a global fit to data from Dark Matter (DM) direct detection experiments, including the recent CDMS-II results. We discuss possible interpretations of the DAMA annual modulation signal in terms of spin-independent and spin-dependent DM-nucleus interactions, both for elastic and inelastic scattering. We find that for the spin-dependent inelastic scattering off protons a good fit to all data is obtained. We present a simple toy model realizing such a scenario. In all the remaining cases the DAMA allowed regions are disfavored by other experiments or suffer from severe fine tuning of DM parameters with respect to the galactic escape velocity. Finally, we also entertain the possibility that the two events observed in CDMS-II are an actual signal of elastic DM scattering, and we compare the resulting CDMS-II allowed regions to the exclusion limits from other experiments.

Kopp, Joachim; Schwetz, Thomas; Zupan, Jure

2009-12-01

211

Direct dark matter search by observing electrons produced in neutralino nucleus collisions

NASA Astrophysics Data System (ADS)

Exotic dark matter and dark energy together seem to dominate in the Universe. Supersymmetry naturally provides a candidate for the dark matter constituents via the lightest supersymmetric particle (LSP). The most important process for directly detecting dark matter is the LSP nucleus elastic scattering by measuring the energy of the recoiling nucleus. In the present work we explore a novel process, which has definite experimental advantages, that is the detection of the dark matter constituents by observing the low energy ionization electrons. These electrons, which are produced during the LSP nucleus collision, may be observed separately or in coincidence with the recoiling nuclei. We develop the formalism and apply it in calculating the ratio of the ionization rate to the nuclear recoil rate in a variety of atoms including 20Ne, 40Ar, 76Ge, 78Kr and 132Xe, employing realistic Hartree Fock electron wave functions. The obtained ratios are essentially independent of all parameters of supersymmetry except the neutralino mass, but they crucially depend on the electron energy cutoff. These ratios per electron tend to increase with the atomic number and can be as high as 10%. Based on our results it is both interesting and realistic to detect the LSP by measuring the ionization electrons following the LSP nuclear collisions.

Moustakidis, Ch. C.; Vergados, J. D.; Ejiri, H.

2005-10-01

212

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

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

213

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

The doping of charge carriers into the CuO(2) 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 La(2-x)Sr(x)CuO(4) 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. PMID:20855579

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

2010-09-20

214

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

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

215

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

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

216

NASA Astrophysics Data System (ADS)

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 search coil magnetometers on Svalbard, at magnetic latitudes from ~74° to ~76° and with interstation separations of ~100 km, to determine the horizontal propagation direction and velocity of a number of Pc1-2 wave events with duration ?1 hour. Using interstation time lags determined by both cross-correlation analysis and cross-phase analysis of filtered dB/dt records, and assuming plane wave fronts, we have determined wave velocities typically near 300 km/s and propagation predominantly from lower latitudes. Hankasalmi SuperDARN radar returns from the Svalbard region were used to estimate the latitude of the cusp. All of the events studied were found to be consistent with wave sources in the outer dayside magnetosphere.

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

2010-12-01

217

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

218

A Search for Direct CP Violation in Two-Body Cabibbo-Suppressed Decays of Neutral Charmed Mesons

Presented are the results of a search for direct CP violation in Cabibbo-suppressed decays of D{sup 0} to two charged daughters. The analysis described was performed on {approx}230 fb{sup -1} of the BABAR data sample, recorded at the Stanford Linear Accelerator Center and using the PEP-II electron storage rings. We measure CP asymmetries for decay to the KK and {pi}{pi} final states, as well as for the branching ratio, and develop a new technique for tagging-efficiency correction using the Cabibbo-favored K{pi} final state. We find some evidence for CP violation in decays to the KK final state and results that suggest CP violation in the {pi}{pi} final state as well.

Flacco, Christian Julienne; /UC, Santa Cruz

2007-11-12

219

PURPOSE: To demonstrate the feasibility of direct virtual coil (DVC) in the setting of 4D dynamic imaging used in multiple clinical applications. THEORY AND METHODS: Three dynamic imaging applications were chosen: pulmonary perfusion, liver perfusion, and peripheral MR angiography (MRA), with 18, 11, and 10 subjects, respectively. After view-sharing, the k-space data were reconstructed twice: once with channel-by-channel (CBC) followed by sum-of-squares coil combination and once with DVC. Images reconstructed using CBC and DVC were compared and scored based on overall image quality by two experienced radiologists using a five-point scale. RESULTS: The CBC and DVC showed similar image quality in image domain. Time course measurements also showed good agreement in the temporal domain. CBC and DVC images were scored as equivalent for all pulmonary perfusion cases, all liver perfusion cases, and four of the 10 peripheral MRA cases. For the remaining six peripheral MRA cases, DVC were scored as slightly better (not clinically significant) than the CBC images by Radiologist A and as equivalent by Radiologist B. CONCLUSION: For dynamic contrast-enhanced MR applications, it is clinically feasible to reduce image reconstruction time while maintaining image quality and time course measurement using the DVC technique. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc. PMID:23441013

Wang, Kang; Beatty, Philip J; Nagle, Scott K; Reeder, Scott B; Holmes, James H; Rahimi, Mahdi S; Bell, Laura C; Korosec, Frank R; Brittain, Jean H

2013-02-25

220

Directed acyclic graphical (DAG) models are increasingly employed in the study of physical and biological systems to model direct influences between variables. Identifying the graph from data is a challenging endeavor, which can be more reasonably tackled if the variables are assumed to satisfy a given ordering; in this case we simply have to estimate the presence or absence of each potential edge. Working under this assumption, we propose an objective Bayesian method for searching the space of Gaussian DAG models, which provides a rich output from minimal input. We base our analysis on non-local parameter priors, which are especially suited for learning sparse graphs, because they allow a faster learning rate, relative to ordinary local parameter priors, when the true unknown sampling distribution belongs to a simple model. We implement an efficient stochastic search algorithm, which deals effectively with data sets having sample size smaller than the number of variables, and apply our method to a variety of simulated and real data sets. Our approach compares favorably, in terms of the ROC curve for edge hit rate versus false alarm rate, to current state-of-the-art frequentist methods relying on the assumption of ordered variables; under this assumption it exhibits a competitive advantage over the PC-algorithm, which can be considered as a frequentist benchmark for unordered variables. Importantly, we find that our method is still at an advantage for learning the skeleton of the DAG, when the ordering of the variables is only moderately mis-specified. Prospectively, our method could be coupled with a strategy to learn the order of the variables, thus dropping the known ordering assumption. PMID:23560520

Altomare, Davide; Consonni, Guido; La Rocca, Luca

2013-04-05

221

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

222

In the United States, regulatory seismic codes (for example, California Building Code) require at least two sets of horizontal ground-motion components for three-dimensional (3D) response history analysis (RHA) of building structures. For sites within 5 kilometers (3.1 miles) of an active fault, these records should be rotated to fault-normal and fault-parallel (FN/FP) directions, and two RHAs should be performed separately—when FN and then FP direction are aligned with transverse direction of the building axes. This approach is assumed to lead to two sets of responses that envelope the range of possible responses over all nonredundant rotation angles. The validity of this assumption is examined here using 3D computer models of single-story structures having symmetric (torsionally stiff) and asymmetric (torsionally flexible) layouts subjected to an ensemble of near-fault ground motions with and without apparent velocity pulses. In this parametric study, the elastic vibration period is varied from 0.2 to 5 seconds, and yield-strength reduction factors, R, are varied from a value that leads to linear-elastic design to 3 and 5. Further validations are performed using 3D computer models of 9-story structures having symmetric and asymmetric layouts subjected to the same ground-motion set. The influence of the ground-motion rotation angle on several engineering demand parameters (EDPs) is examined in both linear-elastic and nonlinear-inelastic domains to form benchmarks for evaluating the use of the FN/FP directions and also the maximum direction (MD). The MD ground motion is a new definition for horizontal ground motions for use in site-specific ground-motion procedures for seismic design according to provisions of the American Society of Civil Engineers/Seismic Engineering Institute (ASCE/SEI) 7-10. The results of this study have important implications for current practice, suggesting that ground motions rotated to MD or FN/FP directions do not necessarily provide the most critical EDPs in nonlinear-inelastic domain; however, they tend to produce larger EDPs than as-recorded (arbitrarily oriented) motions.

Reyes, Juan C.; Kalkan, Erol

2012-01-01

223

NASA Astrophysics Data System (ADS)

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 Véron-Cetty Véron 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 49.3 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.

Pierre Auger Collaboration; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antici'c, T.; Aramo, C.; Arganda, E.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Bäcker, T.; Badescu, A. M.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Barroso, S. L. C.; Baughman, B.; Bäuml, J.; Beatty, J. J.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Bohácová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Caballero-Mora, K. S.; Caccianiga, B.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chirinos Diaz, J.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; del Río, M.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Fajardo Tapia, I.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Filevich, A.; Filipcic, A.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Gascon, A.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, D.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gouffon, P.; Grashorn, E.; Grebe, S.; Griffith, N.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Guzman, A.; Hague, J. D.; Hansen, P.; Harari, D.; Harmsma, S.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horneffer, A.; Horvath, P.; Hrabovský, M.; Huege, T.; Insolia, A.; Ionita, F.; Italiano, A.; Jarne, C.; Jiraskova, S.; Josebachuili, M.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuehn, F.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; Lachaud, C.; Lauer, R.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Mertsch, P.; Meurer, C.; Mi'canovi'c, S.; Micheletti, M. I.; Minaya, I. A.; Miramonti, L.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pekala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.

2012-04-01

224

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

225

NuMA, a 238 kDa protein present in the nucleus during interphase, translocates to the spindle poles in mitosis. NuMA plays an essential role in mitosis, since microinjection of the NuMA SPN-3 monoclonal antibody causes mitotic arrest and micronuclei formation. We have mapped the approximate position of the epitopes of six monoclonal NuMA antibodies using recombinant NuMA fragments. The SPN-3 epitope has been located to residues 255-267 at the C-terminus of the first helical subdomain of the central rod domain and several residues crucial for antibody binding have been identified. To gain insight into the ultrastructure of NuMA, several defined fragments, as well as the full-length recombinant protein, were expressed in Escherichia coli and purified to homogeneity. They were then characterized by chemical cross-linking, circular dichroism spectra and electron microscopy. The results directly reveal the tripartate structure of NuMA. A long central rod domain is flanked by globular end domains. The rod is 207 nm long and is at least 90% alpha-helical. It reflects a double-stranded coiled-coil with the alpha-helices arranged parallel and in register. The NuMA protein thus forms the longest coiled-coil currently known. Our analyses reveal no indication that recombinant NuMA assembles into filaments or other higher order structures. Images

Harborth, J; Weber, K; Osborn, M

1995-01-01

226

Parallelizing assistant for parallel architectures

This research presents the design and implementation of a prototype programming tool for vectorization and parallelization assistance, called the Workstation Vectorization and Parallelization Assistance Environment (WVPAE). The proposed working environment for WVPAE is the workstation. The WVPAE is designed to function as an experimentation facility for interactive vectorization and parallelization assistance during the implementation or maintenance of parallel-computing applications. The target high-level language for implementing parallel-computing applications is chosen to be a Fortran-like language, and the target parallel machine has to be specified by the user. The target parallel-machine architecture can be either a vector or a multiprocessor machine. The assistance provided by the WVPAE is based on analyzing user programs to discover all barriers that may cause either vectorization blocking or parallelization blocking. Vectorization and parallelization barriers are categorized in this research into barriers due to sequential language constructs and those due to dependence relationships. The WVPAE tool provides diagnostic messages and advice for most of the barriers defined in this research.

Arafeh, B.R.

1986-01-01

227

ERIC Educational Resources Information Center

This study examined the effects of three variables on self-scoring accuracy and satisfaction with results on Holland's Self Directed Search. The sample consisted of 489 freshmen who took the SDS during orientation. The three independent variables were the test administrator's attitude toward the SDS (positive or neutral), the size of the group…

Christensen, Kathleen C.; And Others

228

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

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

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

2004-01-01

229

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

230

We describe software that searches for spaceships in Conway's Game of Life and related two-dimensional cellular automata. Our program searches through a state space related to the de Bruijn graph of the automa- ton, using a method that combines features of breadth rst and iterative deepening search, and includes fast bit-parallel graph reachability and path enumeration algorithms for nding the

David Eppstein

2000-01-01

231

Concurrent search structure algorithms

A dictionary is an abstract data type supporting the actions member, insert, and delete. A search structure is a data structure used to implement a dictionary. Examples include B trees, hash structures, and unordered lists. Concurrent algorithms on search structures can achieve more parallelism than standard concurrency control methods would suggest, by exploiting the fact that many different search structure

Dennis Shasha; Nathan Goodman

1988-01-01

232

This paper reports on the development of a parallel version of quicksort on a CRCW PRAM. The algorithm uses n processors and a linear space to sort n keys in the expected time O(log n) with large probability.

Vrto, I. (Inst. of Technical Cybernetics, Slovac Academy of Sciences, Dubravska Cesta 9, 842-37 Bratislava (CS)); Chelbus, B.S. (Dept. of Computer Science, Univ. of California, Riverside, CA (US))

1991-04-01

233

NASA Astrophysics Data System (ADS)

The application of the Luus-Jaakola direct search method to the optimization of stand-alone hybrid energy systems consisting of wind turbine generators (WTG's), photovoltaic (PV) modules, batteries, and an auxiliary generator was examined. The loads for these systems were for agricultural applications, with the optimization conducted on the basis of minimum capital, operating, and maintenance costs. Five systems were considered: two near Edmonton, Alberta, and one each near Lethbridge, Alberta, Victoria, British Columbia, and Delta, British Columbia. The optimization algorithm used hourly data for the load demand, WTG output power/area, and PV module output power. These hourly data were in two sets: seasonal (summer and winter values separated) and total (summer and winter values combined). The costs for the WTG's, PV modules, batteries, and auxiliary generator fuel were full market values. To examine the effects of price discounts or tax incentives, these values were lowered to 25% of the full costs for the energy sources and two-thirds of the full cost for agricultural fuel. Annual costs for a renewable energy system depended upon the load, location, component costs, and which data set (seasonal or total) was used. For one Edmonton load, the cost for a renewable energy system consisting of 27.01 m2 of WTG area, 14 PV modules, and 18 batteries (full price, total data set) was 6873/year. For Lethbridge, a system with 22.85 m2 of WTG area, 47 PV modules, and 5 batteries (reduced prices, seasonal data set) cost 2913/year. The performance of renewable energy systems based on the obtained results was tested in a simulation using load and weather data for selected days. Test results for one Edmonton load showed that the simulations for most of the systems examined ran for at least 17 hours per day before failing due to either an excessive load on the auxiliary generator or a battery constraint being violated. Additional testing indicated that increasing the generator capacity and reducing the maximum allowed battery charge current during the time of the day at which these failures occurred allowed the simulation to successfully operate.

Jatzeck, Bernhard Michael

2000-10-01

234

Parallel computing and multitasking

NASA Astrophysics Data System (ADS)

Over the past decade we have witnessed an evolution of scientific computers in which more and more concurrent or parallel arithmetic operations are allowed. The segmented pipeline arithmetic functional units, direct vectorization, indirect vectorization, multiprocessing and finally multitasking represent stages of development of parallel computation. Algorithms for the solution of physics problems must be tailored, if possible, to the forms required for these various kinds of parallelism. We report on some experiences we have had building and running various parallelized physics codes with particular emphasis on the Cray-2. We show that the implementation of multitasking and the subsequent debugging effort are straightforward. These techniques are applicable to more methods, including implicit ones, than was originally predicted. We present arguments that favor the use of interactive timesharing operating systems, particularly for the multitasking situation.

Anderson, David V.; Horowitz, Eric J.; Koniges, Alice E.; McCoy, Michael G.

1986-12-01

235

Simplified Parallel Domain Traversal

Many data-intensive scientific analysis techniques require global domain traversal, which over the years has been a bottleneck for efficient parallelization across distributed-memory architectures. Inspired by MapReduce and other simplified parallel programming approaches, we have designed DStep, a flexible system that greatly simplifies efficient parallelization of domain traversal techniques at scale. In order to deliver both simplicity to users as well as scalability on HPC platforms, we introduce a novel two-tiered communication architecture for managing and exploiting asynchronous communication loads. We also integrate our design with advanced parallel I/O techniques that operate directly on native simulation output. We demonstrate DStep by performing teleconnection analysis across ensemble runs of terascale atmospheric CO{sub 2} and climate data, and we show scalability results on up to 65,536 IBM BlueGene/P cores.

Erickson III, David J [ORNL

2011-01-01

236

SHAKE is a widely used algorithm to impose general holonomic constraints during molecular simulations. By imposing constraints on stiff degrees of freedom that require integration with small time steps (without the constraints) we are able to calculate trajectories with time steps larger by approximately a factor of two. The larger time step makes it possible to run longer simulations. Another approach to extend the scope of Molecular Dynamics is parallelization. Parallelization speeds up the calculation of the forces between the atoms and makes it possible to compute longer trajectories with better statistics for thermodynamic and kinetic averages. A combination of SHAKE and parallelism is therefore highly desired. Unfortunately, the most widely used SHAKE algorithm (of bond relaxation) is inappropriate for parallelization and alternatives are needed. The alternatives must minimize communication, lead to good load balancing, and offer significantly better performance than the bond relaxation approach. The algorithm should also scale with the number of processors. We describe the theory behind different implementations of constrained dynamics on parallel systems, and their implementation on common architectures.

Elber, Ron; Ruymgaart, A. Peter; Hess, Berk

2011-01-01

237

A directed-search strategy for point mutations in the factor Vlll gene causing hemophilia A was used to screen eight potentially hypermutable CpG dinucleotides occur- ring at sites deemed to be of functional importance. Polymerase chain reaction-amplified DNA samples from 793 unrelated individuals with hemophilia A were screened by discriminant oligonucleotide hybridization. Point muta- tions were identified in 16 patients that

J. K. Pattinson; D. S. Millar; J. H. McVey; C. B. Grundy; K. Wieland; R. S. Mibashan; U. Martinowitz; K. Tan-Un; M. Vidaud; M. Goossens; M. Sampietro; P. M. Mannucci; M. Krawczak; J. Reiss; D. Whitmore; S. Bowcock; R. Wensley; A. Ajani; V. Mitchell; C. Rizza; R. Maia; P. Winter; E. E. Mayne; M. Schwartz; P. J. Green; V. V. Kakkar; E. G. D. Tuddenham; D. N. Cooper

1990-01-01

238

This qualitative research study explored the process by which expert and novice counseling practitioners use the computer-based test interpretation (CBTI) for the Self-Directed Search (SDS).\\u000aTwo groups of people were involved in the study: (a) research participants and (b) student assistants. Research participants were the focus of the study; student assistants were not measured or assessed in any way. Research

Jonathan David Shy

2008-01-01

239

A search for arrival direction clustering in the HiRes-I monocular data above 10 19.5 eV

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

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

2004-01-01

240

Human-Computer Interaction Design based on Guided Search

Because human attentional recourses are limited, efficient selections are essential. Several psychological studies have proposed that targets with a basic feature can attract attention at once or in parallel. In real life, however, searching tasks are not usually directed toward targets defined by a single basic feature and the distractors are often heterogeneous. Current designers can hardly \\

Yuan-Chi Tseng

241

NSDL National Science Digital Library

Students will measure the resistance of resistors that they have drawn on paper with a graphite pencil. They will then connect two resistors in parallel and measure the resistance of the combination. In this activity, it is important that students color v

Horton, Michael

2009-05-30

242

Hybrid acquisition of direct sequence CDMA signals

In direct sequence code division multiple access (DS-CDMA) systems, signal acquisition is necessary before communication can commence. Recent work has shown that the problem of acquisition may be even more restrictive than the problem of error control in limiting the capacity and performance of these systems. Passive matched filters and parallel search schemes have been shown to be able to

Venugopal V. Veeravalli; Carl W. Baum

1996-01-01

243

NASA Astrophysics Data System (ADS)

Heuristic search is a fundamental component of artificial intelligence applications. Because search routines are frequently a computational bottleneck, numerous methods have been explored to increase the efficiency of search. While sequential search methods use exponential amounts of storage and yield exponential run times, parallel algorithms designed for MIMD machines significantly reduce the time spent in search. In this paper, we present a massively- parallel SIMD approach to search named MIDA* search. The components of MIDA* include a very fast distribution algorithm which biases the search to one side of the tree, and an incrementally-deepening depth-first search of all the processors in parallel. We show the results of applying MIDA* to instances of the fifteen puzzle problem. Results reveal an efficiency of 76% and a speedup of 8553% and 492% over serial and 16- processor MIMD algorithms, respectively.

Lyons, Gary; Cook, Diane J.

1992-03-01

244

SearchPad: explicit capture of search context to support Web 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

245

Massively parallel computing system

A parallel computing system and method having improved performance where a program is concurrently run on a plurality of nodes for reducing total processing time, each node having a processor, a memory, and a predetermined number of communication channels connected to the node and independently connected directly to other nodes. The present invention improves performance of the parallel computing system by providing a system which can provide efficient communication between the processors and between the system and input and output devices. A method is also disclosed which can locate defective nodes with the computing system.

Benner, R.E.; Gustafson, J.L.; Montry, G.R.

1989-03-01

246

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

247

Three methods of estimating bacterial productivity were compared using parallel samples of Atlantic Ocean water (within 0.25–15 km of the Georgia coast). The frequency-of-dividing cells (FDC) method and the [3H]thymidine incorporation method gave results which were strongly correlated (r=0.97), but the FDC estimates were always higher (X2 to X7) than the [3H]thymidine estimates. Estimates of bacterial productivity ranged from 2–4×108

Steven Y. Newell; Robert D. Fallon

1982-01-01

248

Parallel processing architecture

The parallel processing architecture provides a processor array which accepts input data at a faster rate that its processing elements are able to execute. The main features of this architecture are its programmability, scalability, high bandwidth communication and low cost. It provides high connectivity while maintaining minimum distance between processor elements. This architecture enables construction of a parallel processing with high bandwidth communication in six directions among the neighboring processors. It provides for future growth into more complex and optimized algorithms, and facilitiates incorporation of hardware advances with little effect on currently installed systems. Parallel processing architecture is useful for data sharing in an array, pattern recognition within a data array and sustaining a data input rate which is higher than the pattern recognition algorithm execution time (particle identification in high energy physics).

Crosetto, D.B.

1992-01-01

249

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

NASA Astrophysics Data System (ADS)

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 ?<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.

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.; Guimaraes da Costa, J.; 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.

2006-05-01

250

Direct Search for Dirac Magnetic Monopoles in pp Collisions at {radical}(s)=1.96 TeV

We search for pair-produced Dirac magnetic monopoles in 35.7 pb{sup -1} of proton-antiproton collisions at {radical}(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/c{sup 2}. Assuming a Drell-Yan pair-production mechanism, we set a mass limit m>360 GeV/c{sup 2}.

Abulencia, A.; Budd, S.; Chu, P.H.; Ciobanu, C.I.; Errede, D.; Errede, S.; Gerberich, H.; Grundler, U.; Junk, T.R.; Kraus, J.; Liss, T.M.; Marino, C.; Pitts, K.; Rogers, E.; Taffard, A.; Veramendi, G.; Vickey, T.; Zhang, X. [University of Illinois, Urbana, Illinois 61801 (United States); Acosta, D.; Cruz, A. [University of Florida, Gainesville, Florida 32611 (United States)] (and others)

2006-05-26

251

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

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

252

Scalable Parallel Crash Simulations

We are pleased to submit our efforts in parallelizing the PRONTO application suite for con- sideration in the SuParCup 99 competition. PRONTO is a finite element transient dynamics simulator which includes a smoothed particle hydrodynamics (SPH) capability; it is similar in scope to the well-known DYNA, PamCrash, and ABAQUS codes. Our efforts over the last few years have produced a fully parallel version of the entire PRONTO code which (1) runs fast and scalably on thousands of processors, (2) has performed the largest finite-element transient dynamics simulations we are aware of, and (3) includes several new parallel algorithmic ideas that have solved some difficult problems associated with contact detection and SPH scalability. We motivate this work, describe the novel algorithmic advances, give performance numbers for PRONTO running on Sandia's Intel Teraflop machine, and highlight two prototypical large-scale computations we have performed with the parallel code. We have successfully parallelized a large-scale production transient dynamics code with a novel algorithmic approach that utilizes multiple decompositions for different key segments of the computations. To be able to simulate a more than ten million element model in a few tenths of second per timestep is unprecedented for solid dynamics simulations, especially when full global contact searches are required. The key reason is our new algorithmic ideas for efficiently parallelizing the contact detection stage. To our knowledge scalability of this computation had never before been demonstrated on more than 64 processors. This has enabled parallel PRONTO to become the only solid dynamics code we are aware of that can run effectively on 1000s of processors. More importantly, our parallel performance compares very favorably to the original serial PRONTO code which is optimized for vector supercomputers. On the container crush problem, a Teraflop node is as fast as a single processor of the Cray Jedi. This means that on the Teraflop machine we can now run simulations with tens of millions of elements thousands of times faster than we could on the Jedi! This is enabling transient dynamics simulations of unprecedented scale and fidelity. Not only can previous applications be run with vastly improved resolution and speed, but qualitatively new and different analyses have been made possible.

Attaway, Stephen; Barragy, Ted; Brown, Kevin; Gardner, David; Gruda, Jeff; Heinstein, Martin; Hendrickson, Bruce; Metzinger, Kurt; Neilsen, Mike; Plimpton, Steve; Pott, John; Swegle, Jeff; Vaughan, Courtenay

1999-06-01

253

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

254

Background With the advent of high throughput genomics and high-resolution imaging techniques, there is a growing necessity in biology\\u000a and medicine for parallel computing, and with the low cost of computing, it is now cost-effective for even small labs or individuals\\u000a to build their own personal computation cluster.\\u000a \\u000a \\u000a \\u000a \\u000a Methods Here we briefly describe how to use commodity hardware to build a low-cost,

Kenneth S Kompass; Thomas J Hoffmann; John S Witte

2011-01-01

255

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

2013-10-01

256

The High Resolution Fly's Eye HiRes-I detector has now been in operation in\\u000amonocular mode for over six years. During that time span, HiRes-I has\\u000aaccumulated a larger exposure to Ultra-High Energy Cosmic Rays (UHECRs) above\\u000a10^19 eV than any other experiment built to date. This presents an\\u000aunprecedented opportunity to search for anisotropy in the arrival directions of\\u000aUHECRs.

Benjamin T. Stokes

2004-01-01

257

NASA Astrophysics Data System (ADS)

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb of s=7 TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results.

ATLAS Collaboration Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdelalim, A. A.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Agustoni, M.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Allbrooke, B. M. M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Altheimer, A.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amelung, C.; Ammosov, V. V.; Amor Dos Santos, S. P.; Amorim, A.; Amram, N.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Atkinson, M.; Aubert, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Avramidou, R.; Axen, D.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, V.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beale, S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, A. K.; Becker, S.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Begel, M.; Behar Harpaz, S.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertella, C.; Bertin, A.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bittner, B.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Bloch, I.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borri, M.; Borroni, S.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; 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.; Bremer, J.; Brendlinger, K.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Broggi, F.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Buat, Q.; Bucci, F.

2013-01-01

258

Direct production of high p sub t leptons and search for additional heavy bosons at 1. 8 TeV

We have studied the production of high p{sub t} electrons and muons and searched for additional heavy charged (W{prime}) and neutral (Z{prime}) vector bosons. We find no evidence for such bosons and set limits of M{sub w}{prime} > 520 GeV and M{sub Z}{prime} > 412 GeV (95% confidence level) assuming Standard Model couplings. The production of high mass electron and muon pairs is consistent with the Standard Model prediction for the Drell-Yan production mechanism. Lower limits of 2.2 TeV and 1.6 TeV (95% confidence level) are set on electron-quark and muon-quark compositeness scale parameters {Lambda}{sub LL}{sup {minus}} associated with an effective contact interaction.

Gold, M. (Lawrence Berkeley Lab., CA (United States))

1991-10-01

259

Electron diffusion in a liquid xenon time projection chamber has recently been used to infer the z coordinate of a particle interaction, from the width of the electron signal. The goal of this technique is to reduce the background event rate by discriminating edge events from bulk events. Analyses of dark matter search data which employ it would benefit from increased longitudinal electron diffusion. We show that a significant increase is expected if the applied electric field is decreased. This observation is trivial to implement but runs contrary to conventional wisdom and practice. We also extract a first measurement of the longitudinal diffusion coefficient, and confirm the expectation that electron diffusion in liquid xenon is highly anisotropic under typical operating conditions.

Sorensen, P

2011-02-14

260

Parallel Information Processing.

ERIC Educational Resources Information Center

|Examines parallel computer architecture and the use of parallel processors for text. Topics discussed include parallel algorithms; performance evaluation; parallel information processing; parallel access methods for text; parallel and distributed information retrieval systems; parallel hardware for text; and network models for information…

Rasmussen, Edie M.

1992-01-01

261

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

262

We present fast adaptive parallel algorithms to compute the sum of N Gaussians at N points. Direct sequential computation of this sum would take O(N{sup 2}) time. The parallel time complexity estimates for our algorithms are O(N/n{sub p}) for uniform point distributions and O( (N/n{sub p}) log (N/n{sub p}) + n{sub p}log n{sub p}) for non-uniform distributions using n{sub p} CPUs. We incorporate a plane-wave representation of the Gaussian kernel which permits 'diagonal translation'. We use parallel octrees and a new scheme for translating the plane-waves to efficiently handle non-uniform distributions. Computing the transform to six-digit accuracy at 120 billion points took approximately 140 seconds using 4096 cores on the Jaguar supercomputer. Our implementation is 'kernel-independent' and can handle other 'Gaussian-type' kernels even when explicit analytic expression for the kernel is not known. These algorithms form a new class of core computational machinery for solving parabolic PDEs on massively parallel architectures.

Sampath, Rahul S [ORNL; Sundar, Hari [Siemens Corporate Research; Veerapaneni, Shravan [New York University

2010-01-01

263

A Container-Iterator Parallel Programming Model

There are several parallel programming models available for numerical computations at different levels of expressibility and ease of use. For the development of new domain specific programming models, a splitting into a distributed data container and parallel data iterators is proposed. Data distribution is implemented in application specific li- braries. Data iterators are directly analysed and compiled automatically into parallel

Gerhard W. Zumbusch

2007-01-01

264

Background The ETS transcription factor Elf5 (also known as ESE-2) is highly expressed in the mammary gland and plays an important role in its development and differentiation. Indeed studies in mice have illustrated an essential role for Elf5 in directing alveologenesis during pregnancy. Although the molecular mechanisms that underlie the developmental block in Elf5 null mammary glands are beginning to be unraveled, this investigation has been hampered by limited information about the identity of Elf5-target genes. To address this shortcoming, in this study we have performed ChIP-cloning experiments to identify the specific genomic segments that are occupied by Elf5 in pregnant mouse mammary glands. Results Sequencing and genomic localization of cis-regulatory regions bound by Elf5 in vivo has identified several potential target genes covering broad functional categories. A subset of these target genes demonstrates higher expression levels in Elf5-null mammary glands suggesting a repressive functional role for this transcription factor. Here we focus on one putative target of Elf5, the Ccnd2 gene that appeared in our screen. We identify a novel Elf5-binding segment upstream of the Ccnd2 gene and demonstrate that Elf5 can transcriptionally repress Ccnd2 by directly binding to the proximal promoter region. Finally, using Elf5-null mammary epithelial cells and mammary glands, we show that loss of Elf5 in vivo leads to up regulation of Ccnd2 and an altered expression pattern in luminal cells. Conclusions Identification of Elf5-targets is an essential first step in elucidating the transcriptional landscape that is shaped by this important regulator. Our studies offer new toolbox in examining the biological role of Elf5 in mammary gland development and differentiation.

2010-01-01

265

Scattering points in parallel coordinates.

In this paper, we present a novel parallel coordinates design integrated with points (Scattering Points in Parallel Coordinates, SPPC), by taking advantage of both parallel coordinates and scatterplots. Different from most multiple views visualization frameworks involving parallel coordinates where each visualization type occupies an individual window, we convert two selected neighboring coordinate axes into a scatterplot directly. Multidimensional scaling is adopted to allow converting multiple axes into a single subplot. The transition between two visual types is designed in a seamless way. In our work, a series of interaction tools has been developed. Uniform brushing functionality is implemented to allow the user to perform data selection on both points and parallel coordinate polylines without explicitly switching tools. A GPU accelerated Dimensional Incremental Multidimensional Scaling (DIMDS) has been developed to significantly improve the system performance. Our case study shows that our scheme is more efficient than traditional multi-view methods in performing visual analysis tasks. PMID:19834165

Yuan, Xiaoru; Guo, Peihong; Xiao, He; Zhou, Hong; Qu, Huamin

266

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

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

267

ENABLING PRIMITIVES FOR COMPILING PARALLEL LANGUAGES

This paper presents three novel languageimplementation primitives---lazy threads,stacklets, andsynchronizers---andshows how they combine to provide a parallel call at nearly the efficiency ofa sequential call. The central idea is to transform parallel calls into parallel-ready sequential calls.Excess parallelism degrades into sequential calls with the attendant efficient stack managementand direct transfer of control and data, unless a call truly needs to execute

1995-01-01

268

The current trend within the Tool and Die manufacturing sector is to machine components directly from hardened material using high speed 5-axis machining. This has been driven by the increasing requirements for cost competitiveness and lead-time reduction. Significant research effort has been applied to the optimisation of the process with factors such as tooling and machining strategies being considerably improved.

M Geldart; P Webb; H Larsson; M Backstrom; N Gindy; K Rask

2003-01-01

269

Consistent first solution speedups in OR-parallel execution of logic programs

The authors consider the problem of searching for one possible solution for a logic program in parallel. Most of the proposed parallel search strategies l = for logic programs fail to provide consistent linear speedups over sequential execution. The speedups vary between sub-linear to super-linear and from run to run. They present search strategies using priorities for OR parallel execution

V. A. B. Ramkumar; L. V. Kale

1990-01-01

270

We search for direct pair production of supersymmetric top quarks and supersymmetric bottom quarks in proton-antiproton collisions at {radical}(s)=1.96 TeV, using 295 pb{sup -1} of data recorded by the Collider Detector at Fermilab (CDF II) experiment. The supersymmetric top (supersymmetric bottom) quarks are selected by reconstructing their decay into a charm (bottom) quark and a neutralino, which is assumed to be the lightest supersymmetric particle. The signature of such processes is two energetic heavy-flavor jets and missing transverse energy. The number of events that pass our selection for each search process is consistent with the expected standard model background. By comparing our results to the theoretical production cross sections of the supersymmetric top and supersymmetric bottom quarks in the minimal supersymmetric standard model, we exclude, at a 95% confidence level in the frame of that model, a supersymmetric top quark mass up to 132 GeV/c{sup 2} for a neutralino mass of 48 GeV/c{sup 2}, and a supersymmetric bottom quark mass up to 193 GeV/c{sup 2} for a neutralino mass of 40 GeV/c{sup 2}.

Aaltonen, T.; Maki, T.; Mehtala, P.; Orava, R.; Osterberg, K.; Saarikko, H.; Remortel, N. van [Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki (Finland); Abulencia, A.; Budd, S.; Ciobanu, C. I.; Errede, D.; Errede, S.; Gerberich, H.; Grundler, U.; Junk, T. R.; Kraus, J.; Marino, C. P.; Pitts, K.; Rogers, E.; Taffard, A. [University of Illinois, Urbana, Illinois 61801 (United States)] (and others)

2007-10-01

271

NASA Astrophysics Data System (ADS)

We search for direct pair production of supersymmetric top quarks and supersymmetric bottom quarks in proton-antiproton collisions at s=1.96TeV, using 295pb-1 of data recorded by the Collider Detector at Fermilab (CDF II) experiment. The supersymmetric top (supersymmetric bottom) quarks are selected by reconstructing their decay into a charm (bottom) quark and a neutralino, which is assumed to be the lightest supersymmetric particle. The signature of such processes is two energetic heavy-flavor jets and missing transverse energy. The number of events that pass our selection for each search process is consistent with the expected standard model background. By comparing our results to the theoretical production cross sections of the supersymmetric top and supersymmetric bottom quarks in the minimal supersymmetric standard model, we exclude, at a 95% confidence level in the frame of that model, a supersymmetric top quark mass up to 132GeV/c2 for a neutralino mass of 48GeV/c2, and a supersymmetric bottom quark mass up to 193GeV/c2 for a neutralino mass of 40GeV/c2.

Aaltonen, T.; Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M. G.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; Annovi, A.; Antos, J.; Aoki, M.; Apollinari, G.; Arisawa, T.; Artikov, A.; Ashmanskas, W.; Attal, A.; Aurisano, A.; Azfar, F.; Azzi-Bacchetta, P.; Azzurri, P.; Bacchetta, N.; Badgett, W.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Baroiant, S.; Bartsch, V.; Bauer, G.; Beauchemin, P.-H.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Belloni, A.; Benjamin, D.; Beretvas, A.; Beringer, J.; Berry, T.; Bhatti, A.; Binkley, M.; Bisello, D.; Bizjak, I.; Blair, R. E.; Blocker, C.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Boisvert, V.; Bolla, G.; Bolshov, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brau, B.; Brigliadori, L.; Bromberg, C.; Brubaker, E.; Budagov, J.; Budd, H. S.; Budd, S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Byrum, K. L.; Cabrera, S.; Campanelli, M.; Campbell, M.; Canelli, F.; Canepa, A.; Carillo, S.; Carlsmith, D.; Carosi, R.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chang, S. H.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, I.; Cho, K.; Chokheli, D.; Chou, J. P.; Choudalakis, G.; Chuang, S. H.; Chung, K.; Chung, W. H.; Chung, Y. S.; Cilijak, M.; Ciobanu, C. I.; Ciocci, M. A.; Clark, A.; Clark, D.; Coca, M.; Compostella, G.; Convery, M. E.; Conway, J.; Cooper, B.; Copic, K.; Cordelli, M.; Cortiana, G.; Crescioli, F.; Cuenca Almenar, C.; Cuevas, J.; Culbertson, R.; Cully, J. C.; Daronco, S.; Datta, M.; D'Auria, S.; Davies, T.; Dagenhart, D.; de Barbaro, P.; de Cecco, S.; Deisher, A.; de Lentdecker, G.; de Lorenzo, G.; Dell'Orso, M.; Delli Paoli, F.; Demortier, L.; Deng, J.; Deninno, M.; de Pedis, D.; Derwent, P. F.; di Giovanni, G. P.; Dionisi, C.; di Ruzza, B.; Dittmann, J. R.; D'Onofrio, M.; Dörr, C.; Donati, S.; Dong, P.; Donini, J.; Dorigo, T.; Dube, S.; Efron, 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.; Forrest, R.; Forrester, S.; Franklin, M.; Freeman, J. C.; Furic, I.; Gallinaro, M.; Galyardt, J.; Garcia, J. E.; Garberson, F.; Garfinkel, A. F.; Gay, C.; Gerberich, H.; Gerdes, D.; Giagu, S.; Giannetti, P.; Gibson, K.; Gimmell, J. L.; Ginsburg, C.; Giokaris, N.; Giordani, M.; Giromini, P.; Giunta, M.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldschmidt, N.; Goldstein, J.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gresele, A.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Grundler, U.; Guimaraes da Costa, J.; Gunay-Unalan, Z.; Haber, C.; Hahn, K.; Hahn, S. R.; Halkiadakis, E.; Hamilton, A.; Han, B.-Y.; Han, J. Y.; Handler, R.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harper, S.; Harr, R. F.; Harris, R. M.; Hartz, M.; Hatakeyama, K.; Hauser, J.; Hays, C.; Heck, M.; Heijboer, A.; Heinemann, B.; Heinrich, J.; Henderson, C.; 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.; Husemann, U.; Huston, J.; Incandela, J.; Introzzi, G.; Iori, M.; Ivanov, A.; Iyutin, B.; James, E.; Jang, D.; Jayatilaka, B.; Jeans, D.; Jeon, E. J.; Jindariani, S.; Johnson, W.; Jones, M.; Joo, K. K.; Jun, S. Y.; Jung, J. E.; Junk, T. R.; Kamon, T.; 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, S. B.; Kim, S. H.; Kim, Y. K.; Kimura, N.; Kirsch, L.; Klimenko, S.; Klute, M.; Knuteson, B.; Ko, B. R.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Korytov, A.; Kotwal, A. V.; Kraan, A. C.; Kraus, J.; Kreps, M.; Kroll, J.; Krumnack, N.; Kruse, M.; Krutelyov, V.; Kubo, T.; Kuhlmann, S. E.; Kuhr, T.; Kulkarni, N. P.; 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.; Lecompte, T.; Lee, J.; Lee, J.; Lee, Y. J.; Lee, S. W.; Lefèvre, R.; Leonardo, N.; Leone, S.; Levy, S.; Lewis, J. D.; Lin, C.; Lin, C. S.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, T.; Lockyer, N. S.; Loginov, A.; Loreti, M.; 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.; Makhoul, K.; Maki, T.; Maksimovic, P.; Malde, S.; Malik, S.; Manca, G.; Manousakis, A.; Margaroli, F.; Marginean, R.; Marino, C.; Marino, C. P.; Martin, A.; Martin, M.; Martin, V.; Martínez, M.; Martínez-Ballarín, R.; Maruyama, T.; Mastrandrea, P.; Masubuchi, T.; Matsunaga, H.; Mattson, M. E.

2007-10-01

272

Parallel asynchronous particle swarm optimization

SUMMARY The high computational cost of complex engineering optimization problems has motivated the development of parallel optimization algorithms. A recent example is the parallel particle swarm optimization (PSO) algorithm, which is valuable due to its global search capabilities. Unfortunately, because existing parallel implementations are synchronous (PSPSO), they do not make efficient use of computational resources when a load imbalance exists. In this study, we introduce a parallel asynchronous PSO (PAPSO) algorithm to enhance computational efficiency. The performance of the PAPSO algorithm was compared to that of a PSPSO algorithm in homogeneous and heterogeneous computing environments for small- to medium-scale analytical test problems and a medium-scale biomechanical test problem. For all problems, the robustness and convergence rate of PAPSO were comparable to those of PSPSO. However, the parallel performance of PAPSO was significantly better than that of PSPSO for heterogeneous computing environments or heterogeneous computational tasks. For example, PAPSO was 3.5 times faster than was PSPSO for the biomechanical test problem executed on a heterogeneous cluster with 20 processors. Overall, PAPSO exhibits excellent parallel performance when a large number of processors (more than about 15) is utilized and either (1) heterogeneity exists in the computational task or environment, or (2) the computation-to-communication time ratio is relatively small.

Koh, Byung-Il; George, Alan D.; Haftka, Raphael T.; Fregly, Benjamin J.

2006-01-01

273

Toward Parallel Document Clustering

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

274

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

275

Totally Parallel Multilevel Algorithms.

National Technical Information Service (NTIS)

Four totally parallel algorithms for the solution of a sparse linear system have common characteristics which become quite apparent when they are implemented on a highly parallel hypercube such as the CM2. These four algorithms are Parallel Superconvergen...

P. O. Frederickson

1988-01-01

276

Implementation of Parallel Algorithms.

National Technical Information Service (NTIS)

Contents: Intermediate Representation for Parallel Implementation; Data Movement on Processor Arrays; Data-Parallel Implementations of Fast Multipole Algorithms for N-Body Interaction; Rate Control in Parallel Algorithms; Implementing Asynchronous Paralle...

J. H. Reif R. Wagner

1993-01-01

277

Special parallel processing workshop

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

278

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

279

Combat Simulation of Individual Soldier Search in Urban Terrain.

National Technical Information Service (NTIS)

This thesis investigates the visual search process and the effect of contextual information on the search process in an urban combat environment. High resolution combat simulation models implement a parallel sweeping or 'windshield wiper' search process t...

M. D. Hasting

2009-01-01

280

Methods for combinatorial and parallel library design.

Diversity has historically played a critical role in design of combinatorial libraries, screening sets and corporate collections for lead discovery. Large library design dominated the field in the 1990s with methods ranging anywhere from purely arbitrary through property based reagent selection to product based approaches. In recent years, however, there has been a downward trend in library size. This was due to increased information about the desirable targets gleaned from the genomics revolution and to the ever growing availability of target protein structures from crystallography and homology modeling. Creation of libraries directed toward families of receptors such as GPCRs, kinases, nuclear hormone receptors, proteases, etc., replaced the generation of libraries based primarily on diversity while single target focused library design has remained an important objective. Concurrently, computing grids and cpu clusters have facilitated the development of structure based tools that screen hundreds of thousands of molecules. Smaller "smarter" combinatorial and focused parallel libraries replaced those early un-focused large libraries in the twenty-first century drug design paradigm. While diversity still plays a role in lead discovery, the focus of current library design methods has shifted to receptor based methods, scaffold hopping/bio-isostere searching, and a much needed emphasis on synthetic feasibility. Methods such as "privileged substructures based design" and pharmacophore based design still are important methods for parallel and small combinatorial library design. This chapter discusses some of the possible design methods and presents examples where they are available. PMID:20838978

Schnur, Dora M; Beno, Brett R; Tebben, Andrew J; Cavallaro, Cullen

2011-01-01

281

National Technical Information Service (NTIS)

This paper describes penalty search based on a modified neighborhood search where move and solution penalty functions attempt to keep the search process out of recently 'explored' regions. During the penalty search process trajectories which may cause a c...

J. M. Nurmilaakso

1996-01-01

282

A Preliminary Investigation into Parallel Routing on a Hypercube Computer

This paper describes an experiment in which parallel routing is performed on a medium grained hypercube parallel processor having 64 processing elements. Each node is a complete 32-bit computer with 128 K-bytes of memory and is connected to the other nodes via a direct hypercube interconnection network. A new parallel routing algorithm was developed to exploit this parallel structure. It

O. A. Olukotun; T. N. Mudge

1987-01-01

283

A preliminary investigation into parallel routing on a hypercube computer

This paper describes an experiment in which parallel routing is performed on a medium grained hypercube parallel processor having 64 processing elements. Each node is a complete 32-bit computer with 128 K-bytes of memory and is connected to the other nodes via a direct hypercube interconnection network. A new parallel routing algorithm was developed to exploit this parallel structure. It

O. A. Olukotun; Trevor N. Mudge

1987-01-01

284

Teaching parallel programming early

In this position paper, we point out the importance of teaching a basic understanding of parallel computations and parallel programming early in computer science education, in order to give students the necessary expertise to cope with future computer architectures that will exhibit an explicitly parallel programming model. We elaborate on a programming model, namely shared- memory bulk-synchronous parallel programming with

Christoph W. Kessler

2006-01-01

285

Parallel multi-computers and artificial intelligence

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

Uhr

1986-01-01

286

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

287

Fast data parallel polygon rendering

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

288

Parallel Computing in Optimization.

National Technical Information Service (NTIS)

One of the major developments in computing in recent years has been the introduction of a variety of parallel computers, and the development of algorithms that effectively utilize their capabilities. Very little of this parallel algorithm development, how...

R. B. Schnabel

1984-01-01

289

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

290

Parallel flow diffusion battery

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, Hsu-Chi (Albuquerque, NM); Cheng, Yung-Sung (Albuquerque, NM)

1984-08-07

291

Parallel flow diffusion battery

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

292

Model of Parallel Performance.

National Technical Information Service (NTIS)

This report introduces a general model of parallel performance. With the goal of developing conceptual and empirical methods for characterizing and understanding parallel algorithms, new definitions of speedup and efficiency have been formulated. These de...

E. A. Carmona M. D. Rice

1989-01-01

293

... do not need to use AND because the search engine automatically finds resources containing all of your search ... Use as a wildcard when you want the search engine to fill in the blank for you; you ...

294

Two portable parallel tridiagonal solvers

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

295

Pthreads for Dynamic Parallelism

Expressing a large number of lightweight, parallel threads in a shared address space significantly eases the task of writing a parallel program. Threads can be dynamically created to execute individual parallel tasks; the implementation schedules these threads onto the processors and effectively balances the load. However, unless the threads scheduler is designed carefully, such a p arallel program may suffer

Girija J. Narlikar; Guy E. Blelloch

1998-01-01

296

Decomposing the Potentially Parallel

NSDL National Science Digital Library

This course provides an introduction to the issues involved in decomposing problems onto parallel machines, and to the types of architectures and programming styles commonly found in parallel computers. The list of topics discussed includes types of decomposition, task farming, regular domain decomposition, unbalanced grids, and parallel molecular dynamics.

Elspeth Minty, Robert Davey, Alan Simpson, David Henty

297

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

298

Database Searching by Managers.

ERIC Educational Resources Information Center

|Managers and executives need the easy and quick access to business and management information that online databases can provide, but many have difficulty articulating their search needs to an intermediary. One possible solution would be to encourage managers and their immediate support staff members to search textual databases directly as they…

Arnold, Stephen E.

299

Educational Search Strategies.

ERIC Educational Resources Information Center

The activities and research directions of the Educational Search Strategies project are outlined in this progress report. A pilot project was undertaken to study the development of problems into research projects. The research was to be divided into three areas: problem perception and problem definition, information search and dissemination, and…

Bjerstedt, Ake; And Others

300

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

301

Database Searching by Managers.

ERIC Educational Resources Information Center

Managers and executives need the easy and quick access to business and management information that online databases can provide, but many have difficulty articulating their search needs to an intermediary. One possible solution would be to encourage managers and their immediate support staff members to search textual databases directly as they now…

Arnold, Stephen E.

302

Parallel Global Aircraft Configuration Design Space Exploration

The preliminary design space exploration for large, interdisciplinary engineering problems is often a difficult and time-consuming task. General techniques are needed that efficiently and methodically search the design space. This work focuses on the use of parallel load balancing techniques integrated with a global optimizer to reduce the computational time of the design space exploration. The method is applied to

CHUCK A. BAKER; LAYNE T. WATSON; BERNARD GROSSMAN; WILLIAM H. MASON; RAPHAEL T. HAFTKA

1999-01-01

303

Parallel test generation and execution with Korat

We present novel algorithms for parallel testing of code that takes structurally complex test inputs. The algorithms build on the Korat algorithm for constraint-based generation of structurally complex test inputs. Given an imperative predicate that species the desired structural constraints and a nitization that bounds the desired input size, Korat performs a systematic search to generate all test inputs (within

Sasa Misailovic; Aleksandar Milicevic; Nemanja Petrovic; Sarfraz Khurshid; Darko Marinov

2007-01-01

304

The Paradyn Parallel Performance Measurement Tool

Paradyn is a performance measurement tool for parallel and distributed programs. Paradyn uses several novel technologies so that it scales to long running programs (hours or days) and large (thousand node) systems, and auto- mates much of the search for performance bottlenecks. It can provide precise performance data down to the pro- cedure and statement level. Paradyn is based on

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

1995-01-01

305

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

306

Parallel Imaging Microfluidic Cytometer

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

307

Performance Studies of a Parallel Processor for Large Linear Programming Problems.

National Technical Information Service (NTIS)

In order to speed up the solution of large linear programming (LP) problems a new parallel processor will be developed. For this processor a parallel algorithm is established and investigated. Several pivot searching strategies are described and compared ...

J. Luo

1986-01-01

308

Introduction to parallel computing

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

309

Characterizing the parallelism in rule-based expert systems

A brief review of two classes of rule-based expert systems is presented, followed by a detailed analysis of potential sources of parallelism at the production or rule level, the subrule level (including match, select, and act parallelism), and at the search level (including AND, OR, and stream parallelism). The potential amount of parallelism from each source is discussed and characterized in terms of its granularity, inherent serial constraints, efficiency, speedup, dynamic behavior, and communication volume, frequency, and topology. Subrule parallelism will yield, at best, two- to tenfold speedup, and rule level parallelism will yield a modest speedup on the order of 5 to 10 times. Rule level can be combined with OR, AND, and stream parallelism in many instances to yield further parallel speedups.

Douglass, R.J.

1984-01-01

310

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

311

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb$^{-1}$ of $\\\\sqrt{s}$ = 7 TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three

Georges Aad; Tatevik Abajyan; Brad Abbott; Jalal Abdallah; Samah Abdel Khalek; Ahmed Ali Abdelalim; Ovsat Abdinov; Rosemarie Aben; Babak Abi; Maris Abolins; Ossama AbouZeid; Halina Abramowicz; Henso Abreu; Bobby Samir Acharya; Leszek Adamczyk; David Adams; Tetteh Addy; Jahred Adelman; Stefanie Adomeit; Paolo Adragna; Tim Adye; Scott Aefsky; Juan Antonio Aguilar-Saavedra; Marco Agustoni; Mohamed Aharrouche; Steven Ahlen; Florian Ahles; Ashfaq Ahmad; Mahsana Ahsan; Giulio Aielli; Taylan Akdogan; Torsten Paul Ake Åkesson; Ginga Akimoto; Andrei Akimov; Mohammad Alam; Muhammad Aftab Alam; Justin Albert; Solveig Albrand; Martin Aleksa; Igor Aleksandrov; Franco Alessandria; Calin Alexa; Gideon Alexander; Gauthier Alexandre; Theodoros Alexopoulos; Muhammad Alhroob; Malik Aliev; Gianluca Alimonti; John Alison; Benedict Allbrooke; Phillip Allport; Sarah Allwood-Spiers; John Almond; Alberto Aloisio; Raz Alon; Alejandro Alonso; Francisco Alonso; Andrew David Altheimer; Barbara Alvarez Gonzalez; Mariagrazia Alviggi; Katsuya Amako; Christoph Amelung; Vladimir Ammosov; Susana Patricia Amor Dos Santos; Antonio Amorim; Nir Amram; Christos Anastopoulos; Lucian Stefan Ancu; Nansi Andari; Timothy Andeen; Christoph Falk Anders; Gabriel Anders; Kelby Anderson; Attilio Andreazza; George Victor Andrei; Xabier Anduaga; Philipp Anger; Aaron Angerami; Francis Anghinolfi; Alexey Anisenkov; Nuno Anjos; Alberto Annovi; Ariadni Antonaki; Mario Antonelli; Alexey Antonov; Jaroslav Antos; Fabio Anulli; Masato Aoki; Sahar Aoun; Ludovica Aperio Bella; Rudi Apolle; Giorgi Arabidze; Ignacio Aracena; Yasuo Arai; Ayana Arce; Samir Arfaoui; Jean-Francois Arguin; Engin Arik; Metin Arik; Aaron James Armbruster; Olivier Arnaez; Vanessa Arnal; Christian Arnault; Andrei Artamonov; Giacomo Artoni; David Arutinov; Shoji Asai; Ruslan Asfandiyarov; Stefan Ask; Barbro Åsman; Lily Asquith; Ketevi Assamagan; Alan Astbury; Markus Atkinson; Bernard Aubert; Etienne Auge; Kamil Augsten; Mathieu Aurousseau; Giuseppe Avolio; Rachel Maria Avramidou; David Axen; Georges Azuelos; Yuya Azuma; Max Baak; Giuseppe Baccaglioni; Cesare Bacci; Andre Bach; Henri Bachacou; Konstantinos Bachas; Moritz Backes; Malte Backhaus; Elisabeta Badescu; Paolo Bagnaia; Seema Bahinipati; Yu Bai; David Bailey; Travis Bain; John Baines; Oliver Keith Baker; Mark Baker; Sarah Baker; Elzbieta Banas; Piyali Banerjee; Swagato Banerjee; Danilo Banfi; Andrea Michelle Bangert; Vikas Bansal; Hardeep Singh Bansil; Liron Barak; Sergei Baranov; Angela Barbaro Galtieri; Tom Barber; Elisabetta Luigia Barberio; Dario Barberis; Marlon Barbero; Dmitri Bardin; Teresa Barillari; Marcello Barisonzi; Timothy Barklow; Nick Barlow; Bruce Barnett; Michael Barnett; Antonio Baroncelli; Gaetano Barone; Alan Barr; Fernando Barreiro; João Barreiro Guimarães da Costa; Pierre Barrillon; Rainer Bartoldus; Adam Edward Barton; Valeria Bartsch; Austin Basye; Richard Bates; Lucia Batkova; Richard Batley; Andreas Battaglia; Michele Battistin; Florian Bauer; Harinder Singh Bawa; Steven Beale; Tristan Beau; Pierre-Hugues Beauchemin; Roberto Beccherle; Philip Bechtle; Hans Peter Beck; Anne Kathrin Becker; Sebastian Becker; Matthew Beckingham; Karl-Heinz Becks; Andrew Beddall; Ayda Beddall; Sourpouhi Bedikian; Vadim Bednyakov; Christopher Bee; Lars Beemster; Michael Begel; Silvia Behar Harpaz; Michael Beimforde; Camille Belanger-Champagne; Paul Bell; William Bell; Gideon Bella; Lorenzo Bellagamba; Francesco Bellina; Massimiliano Bellomo; Alberto Belloni; Olga Beloborodova; Konstantin Belotskiy; Olga Beltramello; Odette Benary; Driss Benchekroun; Katarina Bendtz; Nektarios Benekos; Yan Benhammou; Eleonora Benhar Noccioli; Jorge-Armando Benitez Garcia; Douglas Benjamin; Mathieu Benoit; James Bensinger; Kamal Benslama; Stan Bentvelsen; David Berge; Elin Bergeaas Kuutmann; Nicolas Berger; Frank Berghaus; Elina Berglund; Jürg Beringer; Pauline Bernat; Ralf Bernhard; Catrin Bernius; Tracey Berry; Claudia Bertella; Antonio Bertin; Federico Bertolucci; Maria Ilaria Besana; Geert-Jan Besjes; Nathalie Besson; Siegfried Bethke; Wahid Bhimji; Riccardo-Maria Bianchi; Michele Bianco; Otmar Biebel; Stephen Paul Bieniek; Katharina Bierwagen; Jed Biesiada; Michela Biglietti; Halina Bilokon; Marcello Bindi; Sebastien Binet; Ahmet Bingul; Cesare Bini; Catherine Biscarat; Bernhard Bittner; Kevin Black; Robert Blair; Jean-Baptiste Blanchard; Georges Blanchot; Tomas Blazek; Ingo Bloch; Craig Blocker; Jacek Blocki; Alain Blondel; Walter Blum; Ulrike Blumenschein; Gerjan Bobbink; Victor Bobrovnikov; Simona Serena Bocchetta; Andrea Bocci; Christopher Richard Boddy; Michael Boehler

2012-01-01

312

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

313

Parallel digital forensics infrastructure.

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

314

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

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

315

USING PPP TO PARALLELIZE OPERATIONAL WEATHER FORECAST MODELS FOR MPPS

The Parallelizing Preprocessor is being developed at t he Forecast Systems Laboratory (FSL) to simplify the process of parallelizing operational weather prediction models for Massively Parallel Processors (MPPs). PPP, a component of FSL's Scalable Modeling System, is a Fortran 77 text analysis and translation tool. PPP directives, implemented as Fortran comments, are inserted into the source c ode. This code

Mark W. Govett; Adwait Sathye; James P. Edwards; Leslie B. Hart

316

Distributed game-tree searching

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

ERIC Educational Resources Information Center

Will the stealth superintendent hunt in Cincinnati become tomorrow's standard approach? Search consultants and superintendents offer their views on how far confidentiality should go. Also includes a search firm's process for shielding identities and a confidentiality pledge. (MLF)

Kenney, Linda Chion

2003-01-01

318

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

319

Direct search for dirac magnetic monopoles in p(p)over-bar collisions at root s=1.96 TeV

We search for pair-produced Dirac magnetic monopoles in 35.7 pb(-1) of proton-antiproton collisions at 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\\/c(2). Assuming a Drell-Yan pair-production mechanism, we set a

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. DAuria; M. Donofrio; D. Dagenhart; P. de Barbaro; S. de Cecco; A. Deisher; G. De Lentdecker; M. DellOrso; S. Demers; L. Demortier; J. Deng; M. Deninno; D. De Pedis; P. F. Derwent; C. Dionisi; J. Dittmann; P. DiTuro; C. Dorr; 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. G. 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. Gonzalez; I. Gorelov; A. T. Goshaw; Y. Gotra; K. Goulianos; A. Gresele; M. Griffiths; S. Grinstein; C. Grosso-Pilcher; U. Grundler; J. G. 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. Lefevre; 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. Martinez; 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. M. Fernandez; J. Mulmenstadt; A. Mukherjee; M. Mulhearn; T. Muller; R. Mumford; P. Murat; J. Nachtman; S. Nahn; I. Nakano; A. Napier; D. Naumov; V. Necula; C. Neu; M. S. Neubauer; J. Nielsen; T. Nigmanov; L. Nodulman

2006-01-01

320

Parallelizing Conditional Recurrences

Recursive functions which use conditional constructs are common in functional (and imperative) programs. We present a collection of techniques for handling such functions for a parallel synthesis method. These techniques can help us enlarge the class of sequential functions which could be systematically transformed to parallel equivalent.

Wei-ngan Chin; John Darlington; Yike Guo

1996-01-01

321

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

322

Parallel discrete event simulation

Parallel discrete event simulation (PDES), sometimes called distributed simulation, refers to the execution of a single discrete event simulation program on a parallel computer. PDES has attracted a considerable amount of interest in recent years. From a pragmatic standpoint, this interest arises from the fact that large simulations in engineering, computer science, economics, and military applications, to mention a few,

Richard M. Fujimoto

1990-01-01

323

Performance of Parallel Algorithms.

National Technical Information Service (NTIS)

A notation to express the performance of a parallel computation is developed. A formalization of the performance measures for a parallel algorithm in which Amdahl's law is a special case is given. The general formulation of Amdahl's law is summarized. The...

J. J. Lukkien

1989-01-01

324

NSDL National Science Digital Library

This presentation outlines the importance of and best practices for literature searches on research projects. It includes suggestions for search techniques, rubrics for evaluating sources, and resources to help with the search process. This presentation was developed for a physics senior projects class.

Chottiner, Gary

2010-04-14

325

ERIC Educational Resources Information Center

|In a federal case involving a vice-principal's pat-down search of middle-school students in a cafeteria (for a missing pizza knife), the court upheld the search, saying it was relatively unintrusive and met "TLO's" reasonable-suspicion standards. Principals need reasonable justification for searching a group. (Contains 18 references.) (MLH)|

Zirkel, Perry A.

2000-01-01

326

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

327

ERIC Educational Resources Information Center

In a federal case involving a vice-principal's pat-down search of middle-school students in a cafeteria (for a missing pizza knife), the court upheld the search, saying it was relatively unintrusive and met "TLO's" reasonable-suspicion standards. Principals need reasonable justification for searching a group. (Contains 18 references.) (MLH)

Zirkel, Perry A.

2000-01-01

328

ERIC Educational Resources Information Center

Discusses analytical searching, a process that enables searchers of electronic resources to develop a planned strategy by combining words or phrases with Boolean operators. Defines simple and complex searching, and describes search strategies developed with Boolean logic and truncation. Provides guidelines for teaching students analytical…

Pappas, Marjorie L.

1995-01-01

329

The parallel cylindrical mirror electron energy analyzer

An electrostatic energy analyzer is described that allows parallel acquisition of the energy spectrum of charged particles over a wide range of energies and over the complete range of azimuthal directions. The analyzer is similar to the cylindrical mirror analyzer except that a linear potential variation is applied in the axial direction to the outer cylinder. The analyzer can also

Frank H. Read

2002-01-01

330

Massively parallel mathematical sieves

The Sieve of Eratosthenes is a well-known algorithm for finding all prime numbers in a given subset of integers. A parallel version of the Sieve is described that produces computational speedups over 800 on a hypercube with 1,024 processing elements for problems of fixed size. Computational speedups as high as 980 are achieved when the problem size per processor is fixed. The method of parallelization generalizes to other sieves and will be efficient on any ensemble architecture. We investigate two highly parallel sieves using scattered decomposition and compare their performance on a hypercube multiprocessor. A comparison of different parallelization techniques for the sieve illustrates the trade-offs necessary in the design and implementation of massively parallel algorithms for large ensemble computers.

Montry, G.R.

1989-01-01

331

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

332

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

333

NASA Astrophysics Data System (ADS)

A search for the electroweak pair production of charged sleptons and weak gauginos decaying into final states with two leptons is performed using 4.7 fb-1 of proton-proton collision data at s=7 TeV recorded with the ATLAS experiment at the Large Hadron Collider. No significant excesses are observed with respect to the prediction from Standard Model processes. In the scenario of direct slepton production, if the sleptons decay directly into the lightest neutralino, left-handed slepton masses between 85 and 195 GeV are excluded at 95% confidence level for a 20 GeV neutralino. Chargino masses between 110 and 340 GeV are excluded in the scenario of direct production of wino-like chargino pairs decaying into the lightest neutralino via an intermediate on-shell charged slepton for a 10 GeV neutralino. The results are also interpreted in the framework of the phenomenological minimal supersymmetric Standard Model.

ATLAS Collaboration Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdelalim, A. A.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Agustoni, M.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Allbrooke, B. M. M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Altheimer, A.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amelung, C.; Ammosov, V. V.; Amor Dos Santos, S. P.; Amorim, A.; Amram, N.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M.-L.; Anduaga, X. S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Atkinson, M.; Aubert, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Avramidou, R.; Axen, D.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, V.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beale, S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, A. K.; Becker, S.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Begel, M.; Behar Harpaz, S.; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertella, C.; Bertin, A.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bittner, B.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Bloch, I.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borri, M.; Borroni, S.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Bremer, J.; Brendlinger, K.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Broggi, F.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.

2013-01-01

334

Parallel Implementation of DSMC Using Unstructured Mesh

The parallel implementation of the Direct Simulation Monte Carlo (DSMC) method on memory-distributed machines using unstructured mesh is reported. Physical domain decomposition is used to distribute the workload among multiple processors. A high-speed driven cavity flow is used as the benchmark problem for the validation of the parallel implementation. Three static partitioning techniques including simple coordinate partitioning, two-step partitioning (JOSTLE)

J.-S. Wu; K.-C. Tseng; T.-J. Yang

2003-01-01

335

NASA Astrophysics Data System (ADS)

A search for direct chargino production in anomaly-mediated supersymmetry breaking scenarios is performed in pp collisions at sqrt{s}=7TeV using 4.7 fb-1 of data collected with the ATLAS experiment at the LHC. In these models, the lightest chargino is predicted to have a lifetime long enough to be detected in the tracking detectors of collider experiments. This analysis explores such models by searching for chargino decays that result in tracks with few associated hits in the outer region of the tracking system. The transverse-momentum spectrum of candidate tracks is found to be consistent with the expectation from the Standard Model background processes and constraints on chargino properties are obtained.

Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdelalim, A. A.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Agustoni, M.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Allbrooke, B. M. M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Altheimer, A.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amelung, C.; Ammosov, V. V.; Amor Dos Santos, S. P.; Amorim, A.; Amram, N.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M.-L.; Anduaga, X. S.; Angelidakis, S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Atkinson, M.; Aubert, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Avramidou, R.; Axen, D.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Backus Mayes, J.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Balek, P.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, V.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beale, S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, A. K.; Becker, S.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Begel, M.; Behar Harpaz, S.; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertella, C.; Bertin, A.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bittner, B.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Bloch, I.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borri, M.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; 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.; Bremer, J.; Brendlinger, K.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Broggi, F.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.

2013-01-01

336

A systematic experimental search for two-body hadronic decays of the b quark of the type b{r_arrow}quark+meson is proposed. These reactions have a well-defined experimental signature and they should be theoretically cleaner compared to exclusive decays. Many modes have appreciable branching ratios, and partial rate asymmetries may also be quite large (about 8{percent} {endash}50{percent} ) in several of them. In a few cases electroweak penguins appear to be dominant and may be measurable. CP -violating triple correlation asymmetries provide a clean test of the standard model. {copyright} {ital 1998} {ital The American Physical Society}

Atwood, D. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Soni, A. [Theory Group, Brookhaven National Laboratory, Upton, New York 11973 (United States)

1998-10-01

337

Compositional C++: Compositional Parallel Programming

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

338

NASA Astrophysics Data System (ADS)

The functional abilities and parallel architecture of the human visual system are a rich source of ideas about visual processing. Any visual task that we can perform quickly and effortlessly is likely to have a computational solution using a parallel algorithm. Recently, several such parallel algorithms have been found that exploit information implicit in an image to compute intrinsic properties of surfaces, such as surface orientation, reflectance and depth. These algorithms require a computational architecture that has similarities to that of visual cortex in primates.

Ballard, Dana H.; Hinton, Geoffrey E.; Sejnowski, Terrence J.

1983-11-01

339

Ada was designed from the beginning with parallel processing applications in mind. Its tasking mechanism is a coherent response to the language issues involved in parallel processing, and carefully balances the often conflicting goals of high-level language features on the one hand and efficient implementation on the other. The purpose of this discussion is to place the design of Ada's parallel processing in its proper historical and technical context. In the process we will show how Ada itself has clarified some issues and thus established trends in language design.

Mundie, D.A.; Fisher, D.A.

1986-08-01

340

Nongradient minimization methods for parallel processing computers, part 2

This paper analyzes the mathematical behavior of nongradient parallel minimization algorithms. The convergence of parallel synchronous iterative procedures corresponding to linearly independent direction methods and to mutually conjugate direction methods is discussed. For the latter, convergence with finite termination on quadratic objective functions and convergence on sufficiently smooth nonquadratic objective functions is proved.

C. Sutti

1983-01-01

341

National Technical Information Service (NTIS)

The research supported by this grant falls into three categories: distributed systems, parallel programming, and theory of concurrent compositions. We developed a distributed systems framework, called Infospheres, that allows any Java programmer to create...

M. Chandy

1997-01-01

342

High Performance Parallel Computing.

National Technical Information Service (NTIS)

The accomplishments of the research project 'High Performance Parallel Computing' for the year 1983 span algorithm formulation, paralle programming languages, basic software for the Texas Reconfigurable Array Computer and validation of design concpets for...

J. C. Browne G. J. Lipovski M. Malek

1985-01-01

343

National Technical Information Service (NTIS)

CSIM is a simulator for parallel Lisp, based on a continuation passing interpreter. It models a shared-memory multiprocessor executing programs written in Common Lisp, extended with several primitives for creating and controlling processes. This paper des...

J. S. Weening

1988-01-01

344

Partitioning and parallel radiosity

NASA Astrophysics Data System (ADS)

This paper proposes a theoretical framework, based on domain subdivision for parallel radiosity. Moreover, three various implementation approaches, taking advantage of partitioning algorithms and global shared memory architecture, are presented.

Merzouk, S.; Winkler, C.; Paul, J. C.

1996-03-01

345

Parallel lumigraph reconstruction

This paper presents three techniques for reconstructing Lumigraphs\\/Lightfields on commercial ccNUMA parallel distributed shared memory computers. The first method is a parallel extension of the software-based method proposed in the Lightfield paper. This expands the ray\\/two-plane intersection test along the film plane, which effectively becomes scan conversion. The second method extends this idea by using a shear\\/warp factorization that accelerates

Peter-Pike Sloan; Charles Hansen

1999-01-01

346

The UCLA Parallel PIC Framework (UPIC) has been developed to provide trusted components for the rapid construction of new, parallel Particle-in-Cell (PIC) codes. The Framework uses object-based ideas in Fortran95, and is designed to provide support for various kinds of PIC codes on various kinds of hardware. The focus is on student programmers. The Framework supports multiple numerical methods, different

Viktor K. Decyk; Charles D. Norton

2004-01-01

347

NASA Astrophysics Data System (ADS)

This dissertation describes a search for the decays B 0 ? invisible and B0 ? invisible+gamma, where invisible refers to a final state consisting of long lived particles with a low cross-section for interaction with matter, leading to a low probability of detection in typical particle detectors. While the branching fractions for these decays predicted by the Standard Model are far below what could be feasably measured by current experiments, new physics such as right-handed neutrinos propagating in large extra space-time dimensions or light R-parity violating neutralinos in supersymmetry could greatly enhance the branching fractions. The decays are searched for in data corresponding to 423.5 fb -1 integrated luminosity produced at the Upsilon(4S) resonance collected with the BABAR detector at the PEP-II B factory, corresponding to 2.30 x 108 B0B¯0 pairs. Using those events that contain a hadronically reconstructed neutral B meson, evidence for the signal decays is sought in the remainder of the event. In (5.00 +/- 0.02) x 105 events with a fully reconstructed neutral B meson, a total of 39 events consistent with the B0 ? invisible decay mode are seen in data with an expected background of 28.5 +/- 7.8(stat.)+/-9.2(syst.) events, and 8 events consistent with the B0 ? invisible+gamma decay mode are seen in data mode with an expected background of 14.1 +/- 5.5(stat.)+/-8.1(syst.) events, from which upper limits of B (B0 ? invisible) < 11.7 x 10-5 and of B (B0 ? invisible+gamma) < 4.3 x 10-5 at the 90% confidence level are obtained.

Blount, Nicholas L.

348

NASA Astrophysics Data System (ADS)

In the process of image acquisition, the object of interest may not be evenly illuminated. So an image with shading irregularities would be produced. This type of image is very difficult to analyze. Consequently, a lot of research work concentrates on this problem. In order to remove the light illumination problem, one of the methods is to filter the image. The dc notch filter is one of the spatial domain filters used for reducing the effect of uneven light illumination on the image. Although the dc notch filter is a spatial domain filter, it is still rather time consuming to apply, especially when it is implemented on a microcomputer. To overcome the speed problem, a parallel dc notch filter is proposed. Based on the separability of the algorithm dc of notch filter, image parallelism (parallel image processing model) is used. To improve the performance of the microcomputer, an INMOS IMS B008 Module Mother Board with four IMS T800-17 is installed in the microcomputer. In fact, the dc notch filter is implemented on the transputer network. This parallel dc notch filter creates a great improvement in the computation time of the filter in comparison with the sequential one. Furthermore, the speed-up is used to analyze the performance of the parallel algorithm. As a result, parallel implementation of the dc notch filter on a transputer network gives a real-time performance of this filter.

Kwok, Kam-Cheung; Chan, Ming-Kam

1991-12-01

349

NSDL National Science Digital Library

Another search engine!! Another search engine? Yes, yet another Web search engine has come online, but this one isn't just business as usual. For one thing, there are no graphics, no banner ads, and no fancy portal features, so Raging Search loads very quickly. Another thing that makes it stand out is the ability to customize various parameters like the number of results displayed per page or the amount of detail returned for each result, and have those preferences "stick," so users need not reset them every time they enter the site. Also through this customization interface, users can select the languages of resources they want to search for (including support for various non-English character sets) and opt to include a "translated version" link along with each search result. And last, but certainly not least, all of the above runs atop an AltaVista search engine, consistently rated one of the best search tools on the Web, enhanced with Google-style link analysis technology to help identify the most useful sites. Overall, if you're serious about tracking something down on the Web, then Raging Search is definitely worth a look.

350

A Programmable Preprocessor for Parallelizing Fortran-90

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

351

A Parallel Hybrid Heuristic for the TSP

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

352

The Paradyn parallel performance measurement tools

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

353

Background: The detection, enumeration and isolation of circulating tumour cells (CTCs) have considerable potential to influence the clinical management of patients with breast cancer. There is, however, substantial variability in the rates of positive samples using existing detection techniques. The lack of standardisation of technology hampers the implementation of CTC measurement in clinical routine practice. Methods: This study was designed to directly compare three techniques for detecting CTCs in blood samples taken from 76 patients with metastatic breast cancer (MBC) and from 20 healthy controls: the CellSearch CTC System, the AdnaTest Breast Cancer Select/Detect and a previously developed real-time qRT-PCR assay for the detection of CK-19 and mammaglobin transcripts. Results: As a result, 36% of patients with MBC were positive by the CellSearch System, 22% by the AdnaTest, 26% using RT–PCR for CK-19 and 54% using RT–PCR for mammaglobin. Samples were significantly more likely to be positive for at least one mRNA marker using RT–PCR than using the CellSearch System (P=0.001) or the AdnaTest (P<0.001). Conclusion: We observed a substantial variation in the detection rates of CTCs in blood from breast cancer patients using three different techniques. A higher rate of positive samples was observed using a combined qRT-PCR approach for CK-19 and mammaglobin, which suggests that this is currently the most sensitive technique for detecting CTCs.

Van der Auwera, I; Peeters, D; Benoy, I H; Elst, H J; Van Laere, S J; Prove, A; Maes, H; Huget, P; van Dam, P; Vermeulen, P B; Dirix, L Y

2009-01-01

354

Performance Bounds for Parallel Processors.

National Technical Information Service (NTIS)

A general model of computation on a p-parallel processor is proposed, distinguishing clearly between the logical parallelism (p* processes) inherent in a computation, and the physical parallelism (p processor) available in the computer organization. This ...

R. B. L. Lee

1976-01-01

355

Parallel Cholesky-based reduction for the weighted integer least squares problem

NASA Astrophysics Data System (ADS)

The LLL reduction of lattice vectors and its variants have been widely used to solve the weighted integer least squares (ILS) problem, or equivalently, the weighted closest point problem. Instead of reducing lattice vectors, we propose a parallel Cholesky-based reduction method for positive definite quadratic forms. The new reduction method directly works on the positive definite matrix associated with the weighted ILS problem and is shown to satisfy part of the inequalities required by Minkowski's reduction of positive definite quadratic forms. The complexity of the algorithm can be fixed a priori by limiting the number of iterations. The simulations have clearly shown that the parallel Cholesky-based reduction method is significantly better than the LLL algorithm to reduce the condition number of the positive definite matrix, and as a result, can significantly reduce the searching space for the global optimal, weighted ILS or maximum likelihood estimate.

Xu, Peiliang

2012-01-01

356

Low-Background Screening for Rare Event Experiments Using a Multi Parallel Plate Chamber

NASA Astrophysics Data System (ADS)

Rare event searches, such as double beta decay and direct dark matter (DM) detection, present a host of challenges in detector design and implementation. One of the most limiting factors is the presence of background radiation which originates from radioactive isotope impurities in the materials used to construct the detector. We present a unique method for detecting ultra-low levels of contamination by placing voltages of alternating polarity on several stacked parallel plates separated by a narrow gap in a pressurized gas. Our design exploits the geometry of the well-known single-layer parallel plate chamber (PPC), but uses multiple plates made out of the material being measured. The design, efficiency, and anticipated sensitivity will be discussed.

Sofka, Clement

2009-10-01

357

PDDP: A data parallel programming model. Revision 1

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

358

With the discovery of Na-sulfate minerals on Mars and Europa, recent studies using these minerals have focused on their ability to assist in the detection of bio/organic signatures. This study further investigates the ability of thenardite (Na2SO4) to effectively facilitate the ionization and identification of aromatic amino acids (phenylalanine, tyrosine, and tryptophan) using a technique called geomatrix-assisted laser desorption/ionization (GALDI) in conjunction with a Fourier transform mass spectrometry (FTICR-MS). This technique is based on the ability of a mineral host to facilitate the ionization and detection of bio/organic molecules. Spectra obtained from each aromatic amino acid alone and in combination with thenardite show differences in ionization mechanism and fragmentation patterns. These differences are due to chemical and structural differences between the aromatic side chains of their respective amino acid. Tyrosine and tryptophan when combined with thenardite were observed to undergo cation-attachment ([M+Na]+), due to the high alkali affinity of their aromatic side chains. Subsequent cation substitution of the carboxyl group led to formation double cation-attached peaks ([M-H+Na]Na+). In contrast, phenylalanine mixed with thenardite showed no evidence of Na+ interaction. Understanding how codeposition of amino acids with thenardite can affect the observed mass spectra is important for future exploration missions that are likely to use laser desorption mass spectrometry to search for bio/organic compounds in extraterrestrial environments.

C. Doc Richardson; Nancy W. Hinman; Jill R. Scott

2009-10-01

359

NASA Astrophysics Data System (ADS)

With the discovery of Na-sulphate minerals on Mars and Europa, recent studies using these minerals have focused on their ability to assist in the detection of bio/organic signatures. This study further investigates the ability of thenardite (Na2SO4) to effectively facilitate the ionization and identification of aromatic amino acids (phenylalanine, tyrosine and tryptophan) using a technique called geomatrix-assisted laser desorption/ionization in conjunction with a Fourier transform ion cyclotron resonance mass spectrometry. This technique is based on the ability of a mineral host to facilitate desorption and ionization of bio/organic molecules for detection. Spectra obtained from each aromatic amino acid alone and in combination with thenardite show differences in ionization mechanism and fragmentation patterns. These differences are due to chemical and structural differences between the aromatic side chains of their respective amino acid. Tyrosine and tryptophan when combined with thenardite were observed to undergo cation-attachment ([M+Na]+), due to the high alkali ion affinity of their aromatic side chains. In addition, substitution of the carboxyl group hydrogen by sodium led to formation of [M-H+Na]Na+ peaks. In contrast, phenylalanine mixed with thenardite showed no evidence of Na+ attachment. Understanding how co-deposition of amino acids with thenardite can affect the observed mass spectra is important for future exploration missions that are likely to use laser desorption mass spectrometry to search for bio/organic compounds in extraterrestrial environments.

Doc Richardson, C.; Hinman, Nancy W.; Scott, Jill R.

2009-10-01

360

A feasibility study of multiplexing parallel beam.

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

2013-01-23

361

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

362

Languages for Parallel Processors

NASA Astrophysics Data System (ADS)

The effective programming of parallel computers is much more complex then the programming of conventional serial computers. There are two fundamental models of highly parallel computer architectures: single instruction stream-multiple data stream in which a single program control unit is used to control a set of slave processing elements and multiple instruction stream-multiple data stream in which a set of interconnected independent processors cooperate on a single task. The high level programming language constructs appropriate for each model are discussed.

Reeves, A. P.

363

Development of a Self-Adaptive Web Search Engine

As the Web evolves towards the direction of providing more and more information, locating the desired information efficiently becomes a very important issue. Web search engines are very useful information search tools in the Internet. Current Web search engines produce search results relating to the search terms and the actual information collected by them. Since the selections of the search

Weifeng Zhang; Baowen Xu; Hongji Yang

2001-01-01

364

Multiple predictors and criteria of job search success

The purpose of this study was to examine the combined and differential effects of five job search behaviors (informal sources, formal sources, preparatory search intensity, active search intensity, job search effort) on five criteria of job search success (job interviews, job offers, employment status, person-job fit, and person-organization fit) as well as the direct and moderating effects of job search

Alan M. Saks

2006-01-01

365

A high-throughput search for direct methanol fuel cell anode electrocatalysts of type Pt xBi yPb z

NASA Astrophysics Data System (ADS)

We used a high-throughput method to screen for direct methanol fuel cell anode electrocatalysts in the Pt-Bi-Pb system. Previous studies showed that PtBi and PtPb (both NiAs structure type) were active electrocatalysts for the oxidation of formic acid, but only PtPb was active in oxidizing methanol. We synthesized thin films with continuous composition spreads of the three elements by magnetron sputtering at deposition temperatures from ambient to 510 °C. A fluorescence method was then used to identify compositions that were active toward methanol oxidation. Only films deposited between temperatures of 160 and 400 °C showed electrocatalytic activity. The areas that were active for methanol oxidation showed predominantly the NiAs structure type according to XRD, with optimal activity for compositions near PtBi 0.01Pb 0.53.

Jin, Jing; Prochaska, Mark; Rochefort, Dominic; Kim, David K.; Zhuang, Lin; DiSalvo, Francis J.; van Dover, R. B.; Abruña, Héctor D.

2007-11-01

366

A Parallel Algorithm for Fixed-Length Approximate String-Matching with k-mismatches

NASA Astrophysics Data System (ADS)

This paper deals with the approximate string-matching problem with Hamming distance. The approximate string-matching with k-mismatches problem is to find all locations at which a query of length m matches a factor of a text of length n with k or fewer mismatches. The approximate string-matching algorithms have both pleasing theoretical features, as well as direct applications, especially in computational biology. We consider a generalisation of this problem, the fixed-length approximate string-matching with k -mismatches problem: given a text t, a pattern x and an integer ?, search for all the occurrences in t of all factors of x of length ? with k or fewer mismatches with a factor of t. We present a practical parallel algorithm of comparable simplicity that requires only time, where w is the word size of the machine (e.g. 32 or 64 in practice) and p the number of processors. Thus the algorithm's performance is independent of k and the alphabet size |?|. The proposed parallel algorithm makes use of message-passing parallelism model, and word-level parallelism for efficient approximate string-matching.

Crochemore, Maxime; Iliopoulos, Costas S.; Pissis, Solon P.

367

NASA Astrophysics Data System (ADS)

Contrary to conventional wisdom, the construction of clusters on a lattice can easily be vectorized, namely over each ``generation'' in a breadth first search. This applies directly to e.g. the single cluster variant of the Swendsen-Wang algorithm. On a Cray-YMP, total CPU time was reduced by a factor 3.5 - 7 in actual applications.

Evertz, H. G.

368

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

369

Pillar: A Parallel Implementation Language

As parallelism in microprocessors becomes mainstream, new program- ming languages and environments are emerging to meet the challenges of parallel programming. To support research on these languages, we are developing a low- level language infrastructure called Pillar (derived from Parallel Implementation Language). Although Pillar programs are intended to be automatically generated from source programs in each parallel language, Pillar programs

Todd Anderson; Neal Glew; Peng Guo; Brian T. Lewis; Wei Liu; Zhanglin Liu; Leaf Petersen; Mohan Rajagopalan; James M. Stichnoth; Gansha Wu; Dan Zhang

2007-01-01

370

Graphite: A distributed parallel simulator for multicores

This paper introduces the Graphite open-source distributed parallel multicore simulator infrastructure. Graphite is designed from the ground up for exploration of future multi- core processors containing dozens, hundreds, or even thousands of cores. It provides high performance for fast design space exploration and software development. Several techniques are used to achieve this including: direct execution, seamless mul- ticore and multi-machine

Jason E. Miller; Harshad Kasture; George Kurian; Charles Gruenwald III; Nathan Beckmann; Christopher Celio; Jonathan Eastep; Anant Agarwal

2010-01-01

371

Parallel DNS with Local Grid Refinement

A parallel finite volume method for unstructured grids is used for a direct numerical simulation of the flow around a sphere at Re = 5000 (based on the sphere diameter and undisturbed velocity). The observed flow structures are confirmed by visualization experiments. A quantitative analysis of the Reynolds averaged flow provides a data base for future model evaluations.

V. Seidl; S. Muzaferija; M. Peri?

1997-01-01

372

Parallel Computational Geometry

We present efficient parallel algorithms for several basic problems in computational geometry: convex hulls, Voronoi diagrams,\\u000a detecting line segment intersections, triangulating simple polygons, minimizing a circumscribing triangle, and recursive data-structures\\u000a for three-dimensional queries.

Alok Aggarwal; Bernard Chazelle; Leonidas J. Guibas; Colm Ó'dúnlaing; Chee-keng Yap

1988-01-01

373

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

374

National Technical Information Service (NTIS)

The Pringle is a 64 processor MIMD computer with a 64 M (8 bit) instructions per second execution rate. The Pringle runs programs written for the Configurable, Highly Parallel (CHiP) Computer. That is, the Pringle executes the 64 separate instruction stre...

A. A. Kapauau J. T. Field D. B. Gannon L. Snyder

1984-01-01

375

Parallel Adaptive Mesh Refinement

As large-scale, parallel computers have become more widely available and numerical models and algorithms have advanced, the range of physical phenomena that can be simulated has expanded dramatically. Many important science and engineering problems exhibit solutions with localized behavior where highly-detailed salient features or large gradients appear in certain regions which are separated by much larger regions where the solution

L Diachin; R Hornung; P Plassmann; A WIssink

2005-01-01

376

A hash table is a representation of a set in a linear size data structure that supports constant-time membership queries. We show how to construct a hash table for any given set of n keys in O(lg lg n) parallel time with high probability, using n processors on a weak version of a

Joseph Gil; Yossi Matias

1994-01-01

377

It has recently been argued by Paul Thagard (1986) that parallel computational models of cognition demonstrate the falsity of the popular theory of mind known as funct\\/onal\\/sm. It is my contention that his argument is seriously mistaken and rests on a misunderstanding of the functionalist position. While my primary aim is to defend functionalism from Thagard's attack, in the process

William M. Ramsey

1989-01-01

378

Optimizing parallel reduction operations

A parallel program consists of sets of concurrent and sequential tasks. Often, a reduction (such as array sum) sequentially combines values produced by a parallel computation. Because reductions occur so frequently in otherwise parallel programs, they are good candidates for optimization. Since reductions may introduce dependencies, most languages separate computation and reduction. The Sisal functional language is unique in that reduction is a natural consequence of loop expressions; the parallelism is implicit in the language. Unfortunately, the original language supports only seven reduction operations. To generalize these expressions, the Sisal 90 definition adds user-defined reductions at the language level. Applicable optimizations depend upon the mathematical properties of the reduction. Compilation and execution speed, synchronization overhead, memory use and maximum size influence the final implementation. This paper (1) Defines reduction syntax and compares with traditional concurrent methods; (2) Defines classes of reduction operations; (3) Develops analysis of classes for optimized concurrency; (4) Incorporates reductions into Sisal 1.2 and Sisal 90; (5) Evaluates performance and size of the implementations.

Denton, S.M.

1995-06-01

379

PARALLEL TRIANGULAR MESH REDUCTION

The visualization of large and complex models is required frequently. This is followed by number of operations which must be done before visualization itself, whether it is an analysis of input data or a model simplification. One of the techniques that enhance the computational power is parallel computation. It can be seen that multiprocessor computers are more often available even

MARTIN FRANC; VÁCLAV SKALA

2000-01-01

380

Interprocedural Analysis for Parallelization

This paper presents an extensive empirical evaluation of an interprocedural parallelizing compiler, developed as part of the Stanford SUIF compiler system. The system incorporates a comprehensive and integrated collection of analyses, including privatization and reduction recognition for both array and scalar variables, and symbolic analysis of array subscripts. The interprocedural analysis framework is designed to provide analysis results nearly as

Mary W. Hallt; Brian R. Murphy; Saman P. Amarasinghe; Shih-wei Liao; Monica S. Lam

1995-01-01

381

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

382

Parallel hierarchical radiosity rendering.

National Technical Information Service (NTIS)

In this dissertation, the step-by-step development of a scalable parallel hierarchical radiosity renderer is documented. First, a new look is taken at the traditional radiosity equation, and a new form is presented in which the matrix of linear system coe...

M. Carter

1993-01-01

383

Parallel hierarchical radiosity rendering

In this dissertation, the step-by-step development of a scalable parallel hierarchical radiosity renderer is documented. First, a new look is taken at the traditional radiosity equation, and a new form is presented in which the matrix of linear system coefficients is transformed into a symmetric matrix, thereby simplifying the problem and enabling a new solution technique to be applied. Next, the state-of-the-art hierarchical radiosity methods are examined for their suitability to parallel implementation, and scalability. Significant enhancements are also discovered which both improve their theoretical foundations and improve the images they generate. The resultant hierarchical radiosity algorithm is then examined for sources of parallelism, and for an architectural mapping. Several architectural mappings are discussed. A few key algorithmic changes are suggested during the process of making the algorithm parallel. Next, the performance, efficiency, and scalability of the algorithm are analyzed. The dissertation closes with a discussion of several ideas which have the potential to further enhance the hierarchical radiosity method, or provide an entirely new forum for the application of hierarchical methods.

Carter, M.

1993-07-01

384

Parallel molecular genetic analysis

We describe recent progress in parallel molecular genetic analyses using DNA microarrays, gel-based systems, and capillary electrophoresis and utilization of these approaches in a variety of molecular biology assays. These applications include use of polymorphic markers for mapping of genes and disease-associated loci and carrier detection for genetic diseases. Application of these technologies in molecular diagnostics as well as fluorescent

Steven E McKenzie; Elaine Mansfield; Eric Rappaport; Saul Surrey; Paolo Fortina

1998-01-01

385

It has long been recognized that many direct parallel tridiagonal solvers are only efficient for solving a single tridiagonal equation of large sizes, and they become inefficient when naively used in a three-dimensional ADI solver. In order to improve the parallel efficiency of an ADI solver using a direct parallel solver, we implement the single parallel partition (SPP) algorithm in

Li Yuan; Hong Guo; Zhaohua Yin

2009-01-01

386

Parallelization of the deMon2k code.

The parallelization of the LCGTO-KS-DFT code deMon2k is presented. The parallelization of the three-center electron repulsion integrals, the numerical integration using a direct grid algorithm and the matrix multiplication and diagonalization are described. The efficiency of the parallelization is analyzed by selected benchmark calculations. It is shown that geometry optimizations of systems with more than 8,000 basis functions are feasible on cluster architectures. PMID:16435308

Geudtner, Gerald; Janetzko, Florian; Köster, Andreas M; Vela, Alberto; Calaminici, Patrizia

2006-03-01

387

NASA Astrophysics Data System (ADS)

A search is presented for direct top squark pair production in final states with one isolated electron or muon, jets, and missing transverse momentum in proton-proton collisions at s=7TeV. The measurement is based on 4.7fb-1 of data collected with the ATLAS detector at the LHC. Each top squark is assumed to decay to a top quark and the lightest supersymmetric particle (LSP). The data are found to be consistent with standard model expectations. Top squark masses between 230 GeV and 440 GeV are excluded with 95% confidence for massless LSPs, and top squark masses around 400 GeV are excluded for LSP masses up to 125 GeV.

Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdelalim, A. A.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Agustoni, M.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Allbrooke, B. M. M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Altheimer, A. D.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amram, N.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Atkinson, M.; Aubert, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Avramidou, R.; Axen, D.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, V.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beale, S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, A. K.; Becker, S.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Begel, M.; Behar Harpaz, S.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertella, C.; Bertin, A.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bittner, B.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Bloch, I.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borri, M.; Borroni, S.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; 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.; Bremer, J.; Brendlinger, K.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Broggi, F.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Buat, Q.; Bucci, F.; Buchanan, J.; Buchholz, P.

2012-11-01

388

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

389

Ultrascalable petaflop parallel supercomputer

A massively parallel supercomputer of petaOPS-scale includes node architectures based upon System-On-a-Chip technology, where each processing node comprises a single Application Specific Integrated Circuit (ASIC) having up to four processing elements. The ASIC nodes are interconnected by multiple independent networks that optimally maximize the throughput of packet communications between nodes with minimal latency. The multiple networks may include three high-speed networks for parallel algorithm message passing including a Torus, collective network, and a Global Asynchronous network that provides global barrier and notification functions. These multiple independent networks may be collaboratively or independently utilized according to the needs or phases of an algorithm for optimizing algorithm processing performance. The use of a DMA engine is provided to facilitate message passing among the nodes without the expenditure of processing resources at the node.

Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton On Hudson, NY); Chiu, George (Cross River, NY); Cipolla, Thomas M. (Katonah, NY); Coteus, Paul W. (Yorktown Heights, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Hall, Shawn (Pleasantville, NY); Haring, Rudolf A. (Cortlandt Manor, NY); Heidelberger, Philip (Cortlandt Manor, NY); Kopcsay, Gerard V. (Yorktown Heights, NY); Ohmacht, Martin (Yorktown Heights, NY); Salapura, Valentina (Chappaqua, NY); Sugavanam, Krishnan (Mahopac, NY); Takken, Todd (Brewster, NY)

2010-07-20

390

Parallel multilevel preconditioners

In this paper, we shall report on some techniques for the development of preconditioners for the discrete systems which arise in the approximation of solutions to elliptic boundary value problems. Here we shall only state the resulting theorems. It has been demonstrated that preconditioned iteration techniques often lead to the most computationally effective algorithms for the solution of the large algebraic systems corresponding to boundary value problems in two and three dimensional Euclidean space. The use of preconditioned iteration will become even more important on computers with parallel architecture. This paper discusses an approach for developing completely parallel multilevel preconditioners. In order to illustrate the resulting algorithms, we shall describe the simplest application of the technique to a model elliptic problem.

Bramble, J.H.; Pasciak, J.E.; Xu, Jinchao.

1989-01-01

391

Parallelization: Infectious Disease

NSDL National Science Digital Library

Epidemiology is the study of infectious disease. Infectious diseases are said to be "contagious" among people if they are transmittable from one person to another. Epidemiologists can use models to assist them in predicting the behavior of infectious diseases. This module will develop a simple agent-based infectious disease model, develop a parallel algorithm based on the model, provide a coded implementation for the algorithm, and explore the scaling of the coded implementation on high performance cluster resources.

Weeden, Aaron

392

Scalable Parallel Crash Simulations

We are pleased to submit our efforts in parallelizing the PRONTO application suite for con- sideration in the SuParCup 99 competition. PRONTO is a finite element transient dynamics simulator which includes a smoothed particle hydrodynamics (SPH) capability; it is similar in scope to the well-known DYNA, PamCrash, and ABAQUS codes. Our efforts over the last few years have produced a

Stephen Attaway; Ted Barragy; Kevin Brown; David Gardner; Jeff Gruda; Martin Heinstein; Bruce Hendrickson; Kurt Metzinger; Mike Neilsen; Steve Plimpton; John Pott; Jeff Swegle; Courtenay Vaughan

1999-01-01

393

Xyce parallel electronic simulator.

This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users' Guide. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users' Guide.

Keiter, Eric Richard; Mei, Ting; Russo, Thomas V.; Rankin, Eric Lamont; Schiek, Richard Louis; Thornquist, Heidi K.; Fixel, Deborah A.; Coffey, Todd Stirling; Pawlowski, Roger Patrick; Santarelli, Keith R.

2010-05-01

394

Parallel reduced area multipliers

As developed by Wallace and Dadda, a method for high-speed, parallel multiplication is to generate a matrix of partial products\\u000a and then reduce the partial products to two numbers whose sum is equal to the final product. The resulting two numbers are\\u000a then summed using a fast carry-propagate adder. This paper presents Reduced Area multipliers, which employ a modified reduction

K'andrea C. Bickerstaff; Michael J. Schulte; Earl E. Swartzlander Jr.

1995-01-01

395

Device for balancing parallel strings

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)

1985-01-01

396

Scattering from parallel metallic cylinders with arbitrary cross sections

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

397

Rotating parallel faults: book shelf mechanism

The mechanical analysis of book shelf operations induced by simple shearing shows that, under certain conditions, this operation requires less driving shear stress than an accommodation of the imposed shear by shear-parallel faulting. The operation of cross faults between neighboring Riedel faults in a wrench zone is a typical example. Large-scale rotation of parallel normal faults in domino style (tilted block tectonics) is primarily associated with the extension of ductile substrata. It may be inferred from mechanical arguments and sandbox experiments how the process, and in particular the dip direction of the faults, is controlled by the way the substratal extension progresses, by the direction of a substratal squeeze flow, by the presence of a surface slope, and by the configuration of the rock boundaries that confine the set of faults in the direction of extension.

Mandl, G.

1984-04-01

398

Accelerated Profile HMM Searches.

Profile hidden Markov models (profile HMMs) and probabilistic inference methods have made important contributions to the theory of sequence database homology search. However, practical use of profile HMM methods has been hindered by the computational expense of existing software implementations. Here I describe an acceleration heuristic for profile HMMs, the "multiple segment Viterbi" (MSV) algorithm. The MSV algorithm computes an optimal sum of multiple ungapped local alignment segments using a striped vector-parallel approach previously described for fast Smith/Waterman alignment. MSV scores follow the same statistical distribution as gapped optimal local alignment scores, allowing rapid evaluation of significance of an MSV score and thus facilitating its use as a heuristic filter. I also describe a 20-fold acceleration of the standard profile HMM Forward/Backward algorithms using a method I call "sparse rescaling". These methods are assembled in a pipeline in which high-scoring MSV hits are passed on for reanalysis with the full HMM Forward/Backward algorithm. This accelerated pipeline is implemented in the freely available HMMER3 software package. Performance benchmarks show that the use of the heuristic MSV filter sacrifices negligible sensitivity compared to unaccelerated profile HMM searches. HMMER3 is substantially more sensitive and 100- to 1000-fold faster than HMMER2. HMMER3 is now about as fast as BLAST for protein searches. PMID:22039361

Eddy, Sean R

2011-10-20

399

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

400

ERIC Educational Resources Information Center

Describes indexes to Web resources that have been created by librarians to be more discriminating than the usual Web search engines, some of which are organized by standard classification systems. Includes indexes by solo librarians as well as by groups of librarians, some in public libraries and some in higher education. (LRW)

Jacso, Peter

2001-01-01

401

Supernovae are extremely bright stellar explosions that sometimes outshine the integrated light of the parent galaxies. The physics of their explosions and the variety of supernova types present fascinating problems in stellar evolution, and their intrinsic luminosity makes them useful probes of cosmology. Searches for supernovae are currently underway by both amateur and professional astronomers using telescopes that range from

P. M. Garnavich

2006-01-01

402

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.

403

ERIC Educational Resources Information Center

|Describes indexes to Web resources that have been created by librarians to be more discriminating than the usual Web search engines, some of which are organized by standard classification systems. Includes indexes by solo librarians as well as by groups of librarians, some in public libraries and some in higher education. (LRW)|

Jacso, Peter

2001-01-01

404

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

405

Supporting dynamic parallel object arrays

ABSTRACT We present efficient support for generalized arrays of parallel data driven objects. Array elements are regular C++ objects, and are scattered across the parallel machine. An individual element is addressed by its \\

Orion Sky Lawlor; Laxmikant V. Kalé

2003-01-01

406

Resistor Combinations for Parallel Circuits.

ERIC Educational Resources Information Center

To help simplify both teaching and learning of parallel circuits, a high school electricity/electronics teacher presents and illustrates the use of tables of values for parallel resistive circuits in which total resistances are whole numbers. (MF)

McTernan, James P.

1978-01-01

407

Design of a Parallel Language.

National Technical Information Service (NTIS)

Concurr is a new language for parallel systems. The language is designed as an easy-to-use parallel programming facility. The language also attempts to overcome some 'unnatural' restrictions of previous sequential languages. Clearly, new languages are nee...

J. R. Weisbecker

1988-01-01

408

Improving Between-Shot Fusion Data Analysis with Parallel Structures

In the Phase I project we concentrated on three technical objectives to demonstrate the feasibility of the Phase II project: (1) the development of a parallel MDSplus data handler, (2) the parallelization of existing fusion data analysis packages, and (3) the development of techniques to automatically generate parallelized code using pre-compiler directives. We summarize the results of the Phase I research for each of these objectives below. We also describe below additional accomplishments related to the development of the TaskDL and mpiDL parallelization packages.

CHET NIETER

2005-07-27

409

Synchronous Parallel Kinetic Monte Carlo

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

410

Roo: A parallel theorem prover

We describe a parallel theorem prover based on the Argonne theorem-proving system OTTER. The parallel system, called Roo, runs on shared-memory multiprocessors such as the Sequent Symmetry. We explain the parallel algorithm used and give performance results that demonstrate near-linear speedups on large problems.

Lusk, E.L.; McCune, W.W.; Slaney, J.K.

1991-11-01

411

Interprocedural parallelization analysis in SUIF

As shared-memory multiprocessor systems become widely available, there is an increasing need for tools to simplify the task of developing parallel programs. This paper describes one such tool, the automatic parallelization system in the Stanford SUIF compiler. This article represents a culmination of a several-year research effort aimed at making parallelizing compilers significantly more effective. We have developed a system

Mary W. Hall; Saman P. Amarasinghe; Brian R. Murphy; Shih-Wei Liao; Monica S. Lam

2005-01-01

412

Dependency-driven Parallel Programming

The appearance of low-cost highly parallel hardware architectures has raised the alarm that a radically new way of thinking is required in programming to face the continually increasing parallelism of hard- ware. In our data dependency based framework, we treat data dependencies as first class entities in pro- grams. Programming a highly parallel machine or chip is formulated as finding

Eva Burrows; Magne Haveraaen

413

Direct search algorithms for optimization calculations

: Many different procedures have been proposed for optimization calculationswhen first derivatives are not available. Further, several researchers havecontributed to the subject, including some who wish to prove convergence theorems,and some who wish to make any reduction in the least calculated valueof the objective function. There is not even a key idea that can be used as afoundation of a

M. J. D. Powell

1998-01-01

414

We present the status and prospects of Higgs searches at the Tevatron and the LHC. Results from the Tevatron are using up to 5 fb{sup -} of data collected with the CDF and D0 detectors. The major contributing processes include associated production (WH {yields} l{nu}bb, ZH {yields} {nu}{nu}bb, ZH {yields} llbb) and gluon fusion (gg {yields} H {yields} WW{sup (*)}). Improvements across the full mass range resulting from the larger data sets, improved analyses techniques and increased signal acceptance are discussed. Recent results exclude the SM Higgs boson in a mass range of 160 < m{sub H} < 170 GeV. Searches for the neutral MSSM Higgs boson in the region 90 < m{sub A} < 200 GeV exclude tan {beta} values down to 30 for several benchmark scenarios.

Peters, Krisztian

2009-11-01

415

NSDL National Science Digital Library

Subtitled "a gateway to research-based addiction information for health consumers, health professionals, educators, students, and researchers," this Website offers a directory of annotated links to materials relating to various addictions. Categories include news, the addictions, statistics, populations, treatment, prevention, social issues, organizations, and harm reduction. These main headings break down into a second level of subheadings, and a search engine -- with date and cataloging parameters -- is also provided. While we would not call Addiction Search a comprehensive gateway, its hundreds of frequently updated links serve as an excellent starting point for investigation into any of the commonly recognized addictive conditions. The site is maintained by Emil Chiauzzi, a published clinical psychologist who is currently involved with "developing multimedia and Internet-based addictions interventions."

2000-01-01

416

The MINOS experiment uses the NuMI {nu}{sub {mu}} beam to make precise measurements of neutrino flavor oscillations in the 'atmospheric' neutrino sector. MINOS can also probe the yet-unknown neutrino mixing angle {Theta}{sub 13} by searching for a {nu}{sub e} appearance signal in the {sub {mu}} beam. This paper reviews the techniques developed for the first {nu}{sub e} appearance analysis in MINOS.

Yang, Ting-Jun; /Stanford U., Phys. Dept.

2011-01-01

417

Benchmarking massively parallel architectures

The purpose of this paper is to summarize some initial experiences related to measuring the performance of massively parallel processors (MPPs) at Los Alamos National Laboratory (LANL). Actually, the range of MPP architectures the authors have used is rather limited, being confined mostly to the Thinking Machines Corporation (TMC) Connection Machine CM-2 and CM-5. Some very preliminary work has been carried out on the Kendall Square KSR-1, and efforts related to other machines, such as the Intel Paragon and the soon-to-be-released CRAY T3D are planned. This paper will concentrate more on methodology rather than discuss specific architectural strengths and weaknesses; the latter is expected to be the subject of future reports. MPP benchmarking is a field in critical need of structure and definition. As the authors have stated previously, such machines have enormous potential, and there is certainly a dire need for orders of magnitude computational power over current supercomputers. However, performance reports for MPPs must emphasize actual sustainable performance from real applications in a careful, responsible manner. Such has not always been the case. A recent paper has described in some detail, the problem of potentially misleading performance reporting in the parallel scientific computing field. Thus, in this paper, the authors briefly offer a few general ideas on MPP performance analysis.

Lubeck, O.; Moore, J.; Simmons, M.; Wasserman, H.

1993-07-01

418

Benchmarking massively parallel architectures

The purpose of this paper is to summarize some initial experiences related to measuring the performance of massively parallel processors (MPPs) at Los Alamos National Laboratory (LANL). Actually, the range of MPP architectures the authors have used is rather limited, being confined mostly to the Thinking Machines Corporation (TMC) Connection Machine CM-2 and CM-5. Some very preliminary work has been carried out on the Kendall Square KSR-1, and efforts related to other machines, such as the Intel Paragon and the soon-to-be-released CRAY T3D are planned. This paper will concentrate more on methodology rather than discuss specific architectural strengths and weaknesses; the latter is expected to be the subject of future reports. MPP benchmarking is a field in critical need of structure and definition. As the authors have stated previously, such machines have enormous potential, and there is certainly a dire need for orders of magnitude computational power over current supercomputers. However, performance reports for MPPs must emphasize actual sustainable performance from real applications in a careful, responsible manner. Such has not always been the case. A recent paper has described in some detail, the problem of potentially misleading performance reporting in the parallel scientific computing field. Thus, in this paper, the authors briefly offer a few general ideas on MPP performance analysis.

Lubeck, O.; Moore, J.; Simmons, M.; Wasserman, H.

1993-01-01

419

Parallel superconvergent multigrid

We describe a class of multiscale algorithms for the solution of large sparse linear systems that are particularly well adapted to massively parallel supercomputers. While standard multigrid algorithms are unable to effectively use all processors when computing on coarse grids, the new algorithms utilize the same number of processors at all times. The basic idea is to solve many coarse scale problems simultaneously, combining the results in an optimal way to provide an improved fine scale solution. As a result, convergence rates are much faster than for standard multigrid methods - we have obtained V-cycle convergence rates as good as .0046 with one smoothing application per cycle, and .0013 with two smoothings. On massively parallel machines the improved convergence rate is attained at no extra computational cost since processors that would otherwise be sitting idle are utilized to provide the better convergence. On serial machines the algorithm is slower because of the extra time spent on multiple coarse scales, though in certain cases the improved convergence rate may justify this - particularly in cases where other methods do not converge. In constant coefficient situations the algorithm is easily analyzed theoretically using Fourier methods on a single grid. The fact that only one grid is involved substantially simplifies convergence proofs. A feature of the algorithms is the use of a matched pair of operators: an approximate inverse for smoothing and a superinterpolation operator to move the correction from coarse to fine scales, chosen to optimize the rate of convergence.

Frederickson, P.O.; McBryan, O.A.

1987-01-01

420

Objectives. We examined the antianginal and anti-ischemic effects of oral zatebradine, a direct sinus node inhibitor that has no blood pressure-lowering or negative inotropic effects in patients with chronic stable angina pectoris taking extended-release nifedipine.Background. Heart rate reduction is considered an important pharmacologic mechanism for providing anginal pain relief and anti-ischemic action in patients with chronic stable angina, suggesting a

William H. Frishman; Carl J. Pepine; Robert J. Weiss; Wolfgang M. Baiker

1995-01-01

421

A PARALLEL GENETIC ALGORITHM FOR AUTOMATED ELECTRONIC CIRCUIT DESIGN

We describe a parallel genetic algorithm (GA) that automatically generates circuit designs using evolutionary search. A circuit-construction programming language is introduced and we show how evolution can generate practical analog circuit designs. Our system allows circuit size (number of devices), circuit topology, and device values to be evolved. We present experimental results as applied to analoglter and amplier design tasks.

Jason D. Lohn; Silvano P. Colombano; Dimitris Stassinopoulos

2000-01-01

422

Exploiting Data Parallelism in the Image Content Engine

The Image Content Engine (ICE) is a framework of software and underlying mathematical and physical models that enable scientists and analysts to extract features from Terabytes of imagery and search the extracted features for content relevant to their problem domain. The ICE team has developed a set of tools for feature extraction and analysis of image data, primarily based on the image content. The scale and volume of imagery that must be searched presents a formidable computation and data bandwidth challenge, and a search of moderate to large scale imagery quickly becomes intractable without exploiting high degrees of data parallelism in the feature extraction engine. In this paper we describe the software and hardware architecture developed to build a data parallel processing engine for ICE. We discuss our highly tunable parallel process and job scheduling subsystem, remote procedure invocation, parallel I/O strategy, and our experience in running ICE on a 16 node, 32 processing element (CPU) Linux Cluster. We present performance and benchmark results, and describe how we obtain excellent speedup for the imagery searches in our test-bed prototype.

Miller, W M; Garlick, J E; Weinert, G F; Abdulla, G M

2006-03-09

423

A systolic array parallelizing compiler

This book presents a completely new approach to the problem of systolic array parallelizing compiler. It describes the AL parallelizing compiler for the Warp systolic array, the first working systolic array parallelizing compiler which can generate efficient parallel code for complete LINPACK routines. This book begins by analyzing the architectural strength of the Warp systolic array. It proposes a model for mapping programs onto the machine and introduces the notion of data relations for optimizing the program mapping. Also presented are successful applications of the AL compiler in matrix computation and image processing. A complete listing of the source program and compiler-generated parallel code are given to clarify the overall picture of the compiler. The book concludes that systolic array parallelizing compiler can produce efficient parallel code, almost identical to what the user would have written by hand.

Tseng, P.S. (Bell Communications Research, Inc. (US))

1990-01-01

424

Platinum ratio search versus golden ratio search

In this simulation study, we examine the traditional golden ratio search in view of cost minimization and search risk, and propose an alternative search plan with what we call “platinum ratio”. The golden ratio search has been thought the best for unimodal optimization. However, our study shows that the golden ratio search is the best only in the sense of

Xia Pan

2008-01-01

425

NSDL National Science Digital Library

Tony R. Kuphaldt is the creator of All About Circuits, a collection of online textbooks about circuits and electricity. The site is split into volumes, chapters, and topics to make finding and learning about these subjects convenient. Volume 1, Chapter 5: Series and Parallel Circuits begins by explaining the basic differences between the two types of circuits. The topics then progress to more difficult subject matter such as conductance, and OhmÃ¢ÂÂs law, with a section on building circuits for a more hands-on component. This website would be a great jumping off point for educators who want to teach circuits or a fantastic supplemental resource for students who want or need to learn more.

Kuphaldt, Tony R.

2008-07-01

426

Parallel Detection of Cathodoluminescence.

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. A GEC P8600 Charge-coupled device has been used in the design and fabrication of a parallel detection system or optical multichannel analyser for the analysis of Cathodoluminescence Spectra. The P8600, whilst designed for video applications, is used as a linear array by merging entire rows of pixels together on the on-board output amplifier. A dual slope integration method of correlated double sampling has been used for noise reduction. An analysis of the performance of this system is given and the achieved noise level of 22 electrons is found to be in good agreement with that theoretically possible. A complete description of the circuits is given together with details of its use with a "Link 860" computer/analyser and a "Philips 400" electron microscope. To demonstrate the system, a study of the cathodoluminescent properties of Cadmium Telluride grown by molecular beam epitaxy has been made. In particular the effect of dislocations, stacking faults and twins on luminescence has been studied. Dislocations are seen to cause a quenching of excitonic emission with no corresponding increase in any other emission. The effect of stacking faults was seen to vary between different samples with an enhancement of long wavelength emission seen in poor quality samples. This supports the premise that the faults are nucleated by surface impurities which are also responsible for the enhanced emission. Some twin defects have been found to cause enhanced excitonic emission. This is compatible with the existence of natural quantum wells at twin faults proposed by other workers. The speed with which the parallel detection system can acquire spectra makes it a valuable tool in the study of beam sensitive materials. To demonstrate this, measurements were made of the decay rates of the weak cathodoluminescence from the organic crystal Coronene. These rates were seen to have time constants less than two minutes and such measurements would not have been amenable by conventional methods.

Day, John C. C.

427

NASA Astrophysics Data System (ADS)

A novel method is presented for definition of search lines in a variety of surface segmentation approaches. The method is inspired by properties of electric field direction lines and is applicable to general-purpose n-D shapebased image segmentation tasks. Its utility is demonstrated in graph construction and optimal segmentation of multiple mutually interacting objects. The properties of the electric field-based graph construction guarantee that inter-object graph connecting lines are non-intersecting and inherently covering the entire object-interaction space. When applied to inter-object cross-surface mapping, our approach generates one-to-one and all-to-all vertex correspondent pairs between the regions of mutual interaction. We demonstrate the benefits of the electric field approach in several examples ranging from relatively simple single-surface segmentation to complex multiobject multi-surface segmentation of femur-tibia cartilage. The performance of our approach is demonstrated in 60 MR images from the Osteoarthritis Initiative (OAI), in which our approach achieved a very good performance as judged by surface positioning errors (average of 0.29 and 0.59 mm for signed and unsigned cartilage positioning errors, respectively).

Yin, Y.; Sonka, M.

2010-03-01

428

Parallel computing in conceptual sewer simulations.

Integrated urban drainage modelling is used to analyze how existing urban drainage systems respond to particular conditions. Based on these integrated models, researchers and engineers are able to e.g. estimate long-term pollution effects, optimize the behaviour of a system by comparing impacts of different measures on the desired target value or get new insights on systems interactions. Although the use of simplified conceptual models reduces the computational time significantly, searching the enormous vector space that is given by comparing different measures or that the input parameters span, leads to the fact, that computational time is still a limiting factor. Owing to the stagnation of single thread performance in computers and the rising number of cores one needs to adapt algorithms to the parallel nature of the new CPUs to fully utilize the available computing power. In this work a new developed software tool named CD3 for parallel computing in integrated urban drainage systems is introduced. From three investigated parallel strategies two showed promising results and one results in a speedup of up to 4.2 on an eight-way hyperthreaded quad core CPU and shows even for all investigated sewer systems significant run-time reductions. PMID:20107253

Burger, G; Fach, S; Kinzel, H; Rauch, W

2010-01-01

429

Parallel computation of a maximum-likelihood estimator of a physical map.

Reconstructing a physical map of a chromosome from a genomic library presents a central computational problem in genetics. Physical map reconstruction in the presence of errors is a problem of high computational complexity that provides the motivation for parallel computing. Parallelization strategies for a maximum-likelihood estimation-based approach to physical map reconstruction are presented. The estimation procedure entails a gradient descent search for determining the optimal spacings between probes for a given probe ordering. The optimal probe ordering is determined using a stochastic optimization algorithm such as simulated annealing or microcanonical annealing. A two-level parallelization strategy is proposed wherein the gradient descent search is parallelized at the lower level and the stochastic optimization algorithm is simultaneously parallelized at the higher level. Implementation and experimental results on a distributed-memory multiprocessor cluster running the parallel virtual machine (PVM) environment are presented using simulated and real hybridization data.

Bhandarkar, S M; Machaka, S A; Shete, S S; Kota, R N

2001-01-01

430

Scioto: A Framework for Global-ViewTask Parallelism

We introduce Scioto, Shared Collections of Task Objects, a framework for supporting task-parallelism in one-sided and global-view parallel programming models. Scioto provides lightweight, locality aware dynamic load balancing and interoperates with existing parallel models including MPI, SHMEM, CAF, and Global Arrays. Through task parallelism, the Scioto framework provides a solution for overcoming load imbalance and heterogeneity as well as dynamic mapping of computation onto emerging multicore architectures. In this paper, we present the design and implementation of the Scioto framework and demonstrate its effectiveness on the Unbalanced Tree Search (UTS) benchmark and two quantum chemistry codes: the closed shell Self-Consistent Field (SCF) method and a sparse tensor contraction kernel extracted from a coupled cluster computation. We explore the efficiency and scalability of Scioto through these sample applications and demonstrate that is offers low overhead, achieves good performance on heterogeneous and multicore clusters, and scales to hundreds of processors.

Dinan, James S.; Krishnamoorthy, Sriram; Larkins, D. B.; Nieplocha, Jaroslaw; Sadayappan, Ponnuswamy

2008-09-09

431

Parallel RF transmission in MRI.

Following the development of parallel imaging, parallel transmission describes the use of multiple RF transmit coils. Parallel transmission can be applied to improve RF excitation, in particular, multidimensional, spatially selective RF excitation. For instance, parallel transmission is able to shorten spatially selective RF pulses in two or three dimensions, or to minimize the occurring SAR. One potential major application might be the compensation of patient-induced B(1) inhomogeneities, particularly at high main fields. This paper provides an overview of selected aspects of this new transmission approach. The basic principles of parallel transmission are discussed, initial experimental proofs are described, and the impact of error propagation on coil design for parallel transmission is outlined. PMID:16705630

Katscher, Ulrich; Börnert, Peter

2006-05-01

432

Parallel global optimization with the particle swarm algorithm.

Present day engineering optimization problems often impose large computational demands, resulting in long solution times even on a modern high-end processor. To obtain enhanced computational throughput and global search capability, we detail the coarse-grained parallelization of an increasingly popular global search method, the particle swarm optimization (PSO) algorithm. Parallel PSO performance was evaluated using two categories of optimization problems possessing multiple local minima-large-scale analytical test problems with computationally cheap function evaluations and medium-scale biomechanical system identification problems with computationally expensive function evaluations. For load-balanced analytical test problems formulated using 128 design variables, speedup was close to ideal and parallel efficiency above 95% for up to 32 nodes on a Beowulf cluster. In contrast, for load-imbalanced biomechanical system identification problems with 12 design variables, speedup plateaued and parallel efficiency decreased almost linearly with increasing number of nodes. The primary factor affecting parallel performance was the synchronization requirement of the parallel algorithm, which dictated that each iteration must wait for completion of the slowest fitness evaluation. When the analytical problems were solved using a fixed number of swarm iterations, a single population of 128 particles produced a better convergence rate than did multiple independent runs performed using sub-populations (8 runs with 16 particles, 4 runs with 32 particles, or 2 runs with 64 particles). These results suggest that (1) parallel PSO exhibits excellent parallel performance under load-balanced conditions, (2) an asynchronous implementation would be valuable for real-life problems subject to load imbalance, and (3) larger population sizes should be considered when multiple processors are available. PMID:17891226

Schutte, J F; Reinbolt, J A; Fregly, B J; Haftka, R T; George, A D

2004-12-01

433

A Survey of Parallel Sorting Algorithms.

National Technical Information Service (NTIS)

A rather comprehensive survey of parallel sorting algorithms is included herein. Parallel sorting algorithms are considered in two major categories - the internal parallel sorting algorithms and the external parallel sorting algorithms. Because external s...

D. J. DeWitt D. Friedland D. K. Hsiao M. J. Menon

1981-01-01

434

Minimizing Weighted Tardiness of Jobs with Stochastic Interruptions in Parallel Machines

In this paper, we address the problem of minimizing expected total weighted tardiness of jobs that have stochastic interruptions and that are processed on a set of parallel machines. Our research generalizes the problem of scheduling parallel machines to minimize total weighted tardiness. The proposed solution method is based on the scatter search methodology and implements an innovative structured combination

Manuel Laguna; Pilar Lino; Angeles Pérez; Sacramento Quintanilla; Vicente Valls

435

SAVVYSEARCH: A Metasearch Engine That Learns Which Search Engines to Query

Search engines are among the most successful applications on the Web today. Somany search engines have been created that it is difficult for users to know wherethey are, how to use them and what topics they best address. Meta-search enginesreduce the user burden by dispatching queries to multiple search engines in parallel.The SavvySearch meta-search engine is designed to efficiently query

Adele E. Howe; Daniel Dreilinger

1997-01-01

436

Background The microarray has contributed to developing the omic analysis. However, as it depends basically on the surface reaction, it is hard to perform bulk reactions and sequential multistep reactions. On the other hand, the popular microplate technology, which has a great merit of being able to perform parallel multistep reactions, has come to its limit in increasing the number of wells (currently, up to 9600) and reducing the volume to deal with due to the difficulty in operations. Results Here, we report a novel microarray technology which enables us to explore advanced applications, termed microarray-with-manageable volumes (MMV). The technical essence is in the pipette-free direct parallel transfer from well to well performed by centrifugation, evading the evaporation and adsorption-losses during handling. By developing the MMV plate, accompanying devices and techniques, generation of multiple conditions (256 kinds) and performance of parallel multistep reactions, including PCR and in vitro translation reactions, have been made possible. These were demonstrated by applying the MMV technology to searching lysozyme-crystallizing conditions and selecting peptides aimed for A?-binding or cathepsin E-inhibition. Conclusions With the introduction of a novel concept microarray (MMV) technology, parallel and multistep reactions in sub-?L scale have become possible.

2010-01-01

437

Parallel processing of robot-arm control computation on a multimicroprocessor system

A parallel-processing scheme is described for robot-arm control computation on any number of parallel processors. The scheme employs two multiprocessor scheduling algorithms called, respectively, depth first\\/implicit heuristic search (DF\\/IHS) and critical path\\/most immediate successors first (CP\\/MISF); these were recently developed by the authors. The scheme is applied to the parallel processing of dynamic control computation for the Stanford manipulator. In

HIRONORI KASAHARA; S. Narita

1985-01-01

438

Parallel Monte Carlo reactor neutronics

The issues affecting implementation of parallel algorithms for large-scale engineering Monte Carlo neutron transport simulations are discussed. For nuclear reactor calculations, these include load balancing, recoding effort, reproducibility, domain decomposition techniques, I/O minimization, and strategies for different parallel architectures. Two codes were parallelized and tested for performance. The architectures employed include SIMD, MIMD-distributed memory, and workstation network with uneven interactive load. Speedups linear with the number of nodes were achieved.

Blomquist, R.N.; Brown, F.B.

1994-03-01

439

Cost-Effective Parallel Computing

Many academic papers imply that parallel computing is only worthwhile when applications achieve nearly linear speedup (i.e., execute nearly p times faster on p processors). This note shows that parallel computing is cost-effective whenever speedup exceeds costup---the parallel system cost divided by uniprocessor cost. Furthermore, when applications have large memory requirements (e.g., 512 megabytes), the costup---and hence speedup necessary to

David A. Wood; Mark D. Hill

1995-01-01

440

Parallel Implementation of DSMC Using Unstructured Mesh

NASA Astrophysics Data System (ADS)

The parallel implementation of the Direct Simulation Monte Carlo (DSMC) method on memory-distributed machines using unstructured mesh is reported. Physical domain decomposition is used to distribute the workload among multiple processors. A high-speed driven cavity flow is used as the benchmark problem for the validation of the parallel implementation. Three static partitioning techniques including simple coordinate partitioning, two-step partitioning (JOSTLE) and multi-level partitioning (METIS) are used for static domain decomposition, respectively. A cell renumbering technique is used to improve the memory management efficiency. Results of parallel efficiency show that two-step partitioning using JOSTLE performs the best, with 63% up to 25 processors, due to better load balancing among the processors. The powerful computational capability of the parallel implementation is demonstrated by computing a 2-D, near-continuum, hypersonic flow over a cylinder as well as a 3-D hypersonic flow over a sphere, respectively, both using 25 processors. Results compare reasonably well with previous simulated and experimental studies.

Wu, J.-S.; Tseng, K.-C.; Yang, T.-J.

2003-09-01

441

Evaluation of Parallel Decomposition Methods for Biomechanical Optimizations

As the complexity of musculoskeletal models continues to increase, so will the computational demands of biomechanical optimizations. For this reason, parallel biomechanical optimizations are becoming more common. Most implementations parallelize the optimizer. In this study, an alternate approach is investigated that parallelizes the analysis function (i.e., a kinematic or dynamic simulation) called repeatedly by the optimizer to calculate the cost function and constraints. To evaluate this approach, a system identification problem involving a kinematic ankle joint model was solved using a gradient-based optimizer and three parallel decomposition methods: gradient calculation decomposition, analysis function decomposition, or both methods combined. For a given number of processors, analysis function decomposition exhibited the best performance despite the highest communication and synchronization overhead, while gradient calculation decomposition demonstrated the worst performance due to the fact that the necessary line searches were not performed in parallel. These findings suggest that the method of parallelization most commonly used for biomechanical optimizations may not be the most efficient, depending on the optimization algorithm used. In many applications, the best computational strategy may be to focus on parallelizing the analysis function.

KOH, BYUNG IL; REINBOLT, JEFFREY A.; FREGLY, BENJAMIN J.; GEORGE, ALAN D.

2006-01-01

442

Facilitated DNA Search by Multidomain Transcription Factors: Cross Talk via a Flexible Linker

More than 70% of eukaryotic proteins are composed of multiple domains. However, most studies of the search for DNA focus on individual protein domains and do not consider potential cross talk within a multidomain transcription factor. In this study, the molecular features of the DNA search mechanism were explored for two multidomain transcription factors: human Pax6 and Oct-1. Using a simple computational model, we compared a DNA search of multidomain proteins with a search of isolated domains. Furthermore, we studied how manipulating the binding affinity of a single domain to DNA can affect the overall DNA search of the multidomain protein. Tethering the two domains via a flexible linker increases their affinity to the DNA, resulting in a higher propensity for sliding along the DNA, which is more significant for the domain with the weaker DNA-binding affinity. In this case, the domain that binds DNA more tightly anchors the multidomain protein to the DNA and, via the linker, increases the local concentration of the weak DNA-binding domain (DBD). The tethered domains directly exchange between two parallel DNA molecules via a bridged intermediate, where intersegmental transfer is promoted by the weaker DBD. We found that, in general, the relative affinity of the two domains can significantly affect the cross talk between them and thus their overall capability to search DNA efficiently. The results we obtained by examining various multidomain DNA-binding proteins support the necessity of discrepancies between the DNA-binding affinities of the constituent domains.

Vuzman, Dana; Polonsky, Michal; Levy, Yaakov

2010-01-01

443

Interleaved modulation of parallel three-phase PWM converters used for wind power system

In parallel converters applications, direct parallel topology was respected because of the advantages of small size, low cost, simple structure and easy to extend. However, the coupling effects maybe exist because the parallel converters are connected by non-isolated mode. In this paper the average model was proposed in the rotating coordinate system. As the entire system is a symmetric structure,

Chunxue Wen; Xiaoguang Zhu; Jianlin Li; Honghua Xu

2009-01-01

444

Partitioning and Parallel Development of an Unstructured, Adaptive Flow Solver on the NEC SX-4.

National Technical Information Service (NTIS)

NLR is developing a parallel, unstructured, adaptive flow solver based on hexahedrons. Development is directed to both the numerical algorithm and parallel efficiency. After an earlier do-loop parallelization of the flow solver on a NEX SX-4/16, a paralle...

H. van der Ven J. J. W. van der Vegt

1997-01-01

445

Revisiting parallel catadioptric goniophotometers

NASA Astrophysics Data System (ADS)

A thorough knowledge of the angular distribution of light scattered by an illuminated surface under different angles is essential in numerous industrial and research applications. Traditionally, the angular distribution of a reflected or transmitted light flux as function of the illumination angle, described by the Bidirectional Scattering Distribution Function (BSDF), is measured with a point-by-point scanning goniophotometer yielding impractically long acquisition times. Significantly faster measurements can be achieved by a device capable of simultaneously imaging the far-field distribution of light scattered by a sample onto a two-dimensional sensor array. Such an angular-to-spatial mapping function can be realized with a parallel catadioptric mapping goniophotometer (CMG). In this contribution, we formally establish the design requirement for a reliable CMG. Based on heuristic considerations we show that, to avoid degrading the angular-to-spatial function, the acceptance angle of the lens system inherent to a CMG must be smaller than 60°. By means of a parametric study, we investigate the practical design limitations of a CMG caused by the constraints imposed by the properties of a real lens system. Our study reveals that the values of the key design parameters of a CMG fall within a relatively small range. This imposes the shape of the ellipsoidal reflector and drastically restricts the room for a design trade-off between the sample size and the angular resolution. We provide a quantitative analysis for the key pa