Multi-directional search: A direct search algorithm for parallel machines
Virginia Joanne Torczon
1989-01-01
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
Parallel solver for trajectory optimization search directions
NASA Technical Reports Server (NTRS)
Psiaki, M. L.; Park, K. H.
1992-01-01
A key algorithmic element of a real-time trajectory optimization hardware/software implementation is presented, the search step solver. This is one piece of an algorithm whose overall goal is to make nonlinear trajectory optimization fast enough to provide real-time commands during guidance of a vehicle such as an aeromaneuvering orbiter or the National Aerospace Plane. Many methods of nonlinear programming require the solution of a quadratic program (QP) at each iteration to determine the search step. In the trajectory optimization case, the QP has a special dynamic programming structure. The algorithm exploits this special structure with a divide- and conquer type of parallel implementation. The algorithm solves a (p.N)-stage problem on N processors in O(p + log2 N) operations. The algorithm yields a factor of 8 speed-up over the fastest known serial algorithm when solving a 1024-stage test problem on 32 processors.
Multi-directional search: A direct search algorithm for parallel machines
Torczon, V.J.
1989-01-01
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 which neither compute nor approximate any derivatives of the objective function. His work, in fact, was inspired by the simplex method of Spendley, Hext, and Himsworth, and the simplex method of Nelder and Mead. The multi-directional search algorithm is inherently parallel. The basic idea of the algorithm is to perform concurrent searches in multiple directions. These searches are free of any interdependencies, so the information required can be computed in parallel. A central result of his work is the convergence analysis for his algorithm. By requiring only that the function be continuously differentiable over a bounded level set, he can prove that a subsequence of the points generated by the multi-directional search algorithm converges to a stationary point of the objective function. This is of great interest since he knows of few convergence results for practical direct search algorithms. He also presents numerical results indicating that the multidirectional search algorithm is robust, even in the presence of noise. His results include comparisons with the Nelder-Mead simplex algorithm, the method of steepest descent, and a quasi-Newton method. One surprising conclusion of his numerical tests is that the Nelder-Mead simplex algorithm is not robust. He closes with some comments about future directions of research.
Parallel solver for trajectory optimization search directions
M. L. Psiaki; K. H. Park
1992-01-01
A key algorithmic element of a real-time trajectory optimization hardware\\/software implementation is presented, the search step solver. This is one piece of an algorithm whose overall goal is to make nonlinear trajectory optimization fast enough to provide real-time commands during guidance of a vehicle such as an aeromaneuvering orbiter or the National Aerospace Plane. Many methods of nonlinear programming require
The complexity of parallel search
Karp, R.M.; Upfal, E.; Wigderson, A.
1987-01-01
This paper studies parallel search algorithms within the framework of independence systems. It is motivated by earlier work on parallel algorithms for concrete problems such as determining a maximal independent set of vertices or a maximum matching in a graph, and by the general question of determining the parallel complexity of a search problem when an oracle is available to solve the associated decision problem. The results provide a parallel analogue of the self-reducibility process that is so useful in sequential computation.
Efficiency of parallel direct optimization
NASA Technical Reports Server (NTRS)
Janies, D. A.; Wheeler, W. C.
2001-01-01
Tremendous progress has been made at the level of sequential computation in phylogenetics. However, little attention has been paid to parallel computation. Parallel computing is particularly suited to phylogenetics because of the many ways large computational problems can be broken into parts that can be analyzed concurrently. In this paper, we investigate the scaling factors and efficiency of random addition and tree refinement strategies using the direct optimization software, POY, on a small (10 slave processors) and a large (256 slave processors) cluster of networked PCs running LINUX. These algorithms were tested on several data sets composed of DNA and morphology ranging from 40 to 500 taxa. Various algorithms in POY show fundamentally different properties within and between clusters. All algorithms are efficient on the small cluster for the 40-taxon data set. On the large cluster, multibuilding exhibits excellent parallel efficiency, whereas parallel building is inefficient. These results are independent of data set size. Branch swapping in parallel shows excellent speed-up for 16 slave processors on the large cluster. However, there is no appreciable speed-up for branch swapping with the further addition of slave processors (>16). This result is independent of data set size. Ratcheting in parallel is efficient with the addition of up to 32 processors in the large cluster. This result is independent of data set size. c2001 The Willi Hennig Society.
NASA Astrophysics Data System (ADS)
Gascon, J.
2005-06-01
Direct dark matter searches consist in observing in the laboratory nuclear recoils due to impact of WIMPs from our galactic halo. The status and perspectives of the leading experiments devoted to this search are discussed.
Parallelized direct execution simulation of message-passing parallel programs
NASA Technical Reports Server (NTRS)
Dickens, Phillip M.; Heidelberger, Philip; Nicol, David M.
1994-01-01
As massively parallel computers proliferate, there is growing interest in findings ways by which performance of massively parallel codes can be efficiently predicted. This problem arises in diverse contexts such as parallelizing computers, parallel performance monitoring, and parallel algorithm development. In this paper we describe one solution where one directly executes the application code, but uses a discrete-event simulator to model details of the presumed parallel machine such as operating system and communication network behavior. Because this approach is computationally expensive, we are interested in its own parallelization specifically the parallelization of the discrete-event simulator. We describe methods suitable for parallelized direct execution simulation of message-passing parallel programs, and report on the performance of such a system, Large Application Parallel Simulation Environment (LAPSE), we have built on the Intel Paragon. On all codes measured to date, LAPSE predicts performance well typically within 10 percent relative error. Depending on the nature of the application code, we have observed low slowdowns (relative to natively executing code) and high relative speedups using up to 64 processors.
NASA Astrophysics Data System (ADS)
Gascon, J.
2004-03-01
Different techniques are currently competing in the direct search of Weakly Interacting Massive Particles (WIMP) dark matter, which consists in observing in the laboratory nuclear recoils due to impact of WIMPs from our galactic halo. As an introduction to this Dark Matter session, the experimental context, the key challenges and the different techniques will be briefly summarized. The performance achieved by low-temperature detectors confers to them a leading role in this domain.
N. J. Spooner
2007-05-23
For many working in particle physics and cosmology successful discovery and characterisation of the new particles that most likely explain the non-baryonic cold dark matter, known to comprise the majority of matter in the Universe, would be the most significant advance in physics for a century. Reviewed here is the current status of direct searches for such particles, in particular the so-called Weakly Interacting Massive Particles (WIMPs), together with a brief overview of the possible future direction of the field extrapolated from recent advances. Current best limits are at or below 10-7 pb for spin-independent neutralino coupling, sufficient that experiments are already probing SUSY models. However, new detectors with tonne-scale mass and/or capability to correlate signal events to our motion through the Galaxy will likely be needed to determine finally whether WIMPs exist.
Parallel search of strongly ordered game trees
Marsland, T.A.; Campbell, M.
1982-12-01
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.
A Generalisation of Indexing for Parallel Document Search
Graham, Nick
of indexes that provide powerful search capability and performance even on modestlyparallel computers. We. Parallel document processing systems are capable of evaluating searches described by arbitrary regularA Generalisation of Indexing for Parallel Document Search D.B. Skillicorn skill
A Generalisation of Indexing for Parallel Document Search
Graham, Nick
of indexes that provide powerful search capability and performance even on modestly-parallel computers. We. Parallel document processing systems are capable of evaluating searches described by arbitrary regularA Generalisation of Indexing for Parallel Document Search D.B. Skillicorn skill
Parallel depth first search. Part I. Implementation
Rao, V.N.; Kumar, V.
1987-12-01
This paper presents a parallel formation of depth-first search which retains the storage efficiency of sequential depth-first search and can be mapped on to any MIMD architecture. To study its effectiveness it has been implemented to solve the 15-puzzle problem on three commercially available multiprocessors - Sequent Balance 21,000, the Intel Hypercube and BBN Butterfly. The authors have been able to achieve fairly linear speedup on Sequent up to 30 processors (the maximum configuration available) and on the Intel Hypercube and BBN Butterfly up to 128 processors (the maximum configurations available). Many researchers considered the ring architecture to be quite suitable for parallel depth-first search. Their experimental results show that hypercube and shared-memory architectures are significantly better. At the heart of their parallel formulation is a dynamic work distribution scheme that divides the work between different processors. The effectiveness of the parallel formulation is strongly influenced by the work distribution scheme and architectural features such as presence/absence of shared memory, the diameter of the network, relative speed of the communication network, etc. In a companion paper, they analyze the effectiveness of different load-balancing schemes and architectures, and also present new improved work distribution schemes.
Toward a Taxonomy of Parallel Tabu Search Heuristics
Teodor Gabriel Crainic; Michel Toulouse; Michel Gendreau
1997-01-01
In this paper we present a classification of parallel tabu search metaheuristicsbased, on the one hand, on the control and communication strategies used in thedesign of the parallel tabu search procedures and, on the other hand, on how the searchspace is partitionned. These criteria are then used to review the parallel tabu searchimplementations described in the literature. The taxonomy is
Ruml, Wheeler
Seth Lemons (UNH) Parallel Best-First Search: Optimal and Suboptimal Solutions 1 / 39 Parallel s Motivation s Overview s Parallel Search s Abstraction PBNF Suboptimal Search Anytime Search Conclusion Seth Lemons (UNH) Parallel Best-First Search: Optimal and Suboptimal Solutions 2 / 39 Now we
Parallel Implementation of a Random Search Procedure: An Experimental Study
Krivulin, Nikolai K.
functions which can be defined as a response to a controllable real-time process, or obtained throughParallel Implementation of a Random Search Procedure: An Experimental Study NIKOLAI K. KRIVULIN computer simulation. To solve the problems, a random search algorithm and its parallel implementation
Search intensity, directed search and the wage distribution Bruno Decreusey
Paris-Sud XI, Université de
relies on the organization of the search market and the search behavior of the job-seekers. The search of a paper that circulated under the title "Job search with ubiquity and the wage distribution". We thankSearch intensity, directed search and the wage distribution Bruno Decreusey University of Aix
Parallel analog neural networks for tree searching
NASA Astrophysics Data System (ADS)
Saylor, Janet; Stork, David G.
1986-08-01
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.
Exploiting Visualization and Direct Manipulation to Make Parallel Tools More
Pancake, Cherri M.
Exploiting Visualization and Direct Manipulation to Make Parallel Tools More Communicative Cherri M@cs.orst.edu http://www.cs.orst.edu/ pancake Abstract. Parallel tools rely on graphical techniques to improve be exploited in parallel tools, in order to improve the naturalness with which the user interacts
Asynchronous parallel generating set search for linearly-constrained optimization.
Kolda, Tamara G.; Griffin, Joshua; Lewis, Robert Michael
2007-04-01
We describe an asynchronous parallel derivative-free algorithm for linearly-constrained optimization. Generating set search (GSS) is the basis of ourmethod. At each iteration, a GSS algorithm computes a set of search directionsand corresponding trial points and then evaluates the objective function valueat each trial point. Asynchronous versions of the algorithm have been developedin the unconstrained and bound-constrained cases which allow the iterations tocontinue (and new trial points to be generated and evaluated) as soon as anyother trial point completes. This enables better utilization of parallel resourcesand a reduction in overall runtime, especially for problems where the objec-tive function takes minutes or hours to compute. For linearly-constrained GSS,the convergence theory requires that the set of search directions conform to the3 nearby boundary. The complexity of developing the asynchronous algorithm forthe linearly-constrained case has to do with maintaining a suitable set of searchdirections as the search progresses and is the focus of this research. We describeour implementation in detail, including how to avoid function evaluations bycaching function values and using approximate look-ups. We test our imple-mentation on every CUTEr test problem with general linear constraints and upto 1000 variables. Without tuning to individual problems, our implementationwas able to solve 95% of the test problems with 10 or fewer variables, 75%of the problems with 11-100 variables, and nearly half of the problems with100-1000 variables. To the best of our knowledge, these are the best resultsthat have ever been achieved with a derivative-free method. Our asynchronousparallel implementation is freely available as part of the APPSPACK software.4
Automatic Generation of Directive-Based Parallel Programs for Shared Memory Parallel Systems
NASA Technical Reports Server (NTRS)
Jin, Hao-Qiang; Yan, Jerry; Frumkin, Michael
2000-01-01
The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. As great progress was made in hardware and software technologies, performance of parallel programs with compiler directives has demonstrated large improvement. The introduction of OpenMP directives, the industrial standard for shared-memory programming, has minimized the issue of portability. Due to its ease of programming and its good performance, the technique has become very popular. In this study, we have extended CAPTools, a computer-aided parallelization toolkit, to automatically generate directive-based, OpenMP, parallel programs. We outline techniques used in the implementation of the tool and present test results on the NAS parallel benchmarks and ARC3D, a CFD application. This work demonstrates the great potential of using computer-aided tools to quickly port parallel programs and also achieve good performance.
Worst Case Complexity of Direct Search
2010-05-13
May 13, 2010 ... and using a framework of the type of GSS (generating set search). ... of pattern search, generalized pattern search (GPS), mesh adaptive direct ... of the behavior of the step size parameter ?k which must approach zero as.
In Search of Sweet-Spots in Parallel Performance Monitoring
Miller, Barton P.
In Search of Sweet-Spots in Parallel Performance Monitoring Aroon Nataraj, Allen D. Malony, Alan and evaluation framework to determine the sweet-spots for performance moni- toring using TAU and MRNet. I
A comparison of some parallel gametree search algorithms (Revised version)
Finkel, Raphael
methods: alphabeta, mandatory work first, principalvariation splitting, tree split ting, ER, and delay trees, heuristic search, alphabeta 1. Introduction In this paper we compare some of the parallel heuristics, such as the alphabeta method, to cut off fruitless search. # Apply many computers simultaneously
Computational efficiency of parallel combinatorial OR-tree searches
NASA Technical Reports Server (NTRS)
Li, Guo-Jie; Wah, Benjamin W.
1990-01-01
The performance of parallel combinatorial OR-tree searches is analytically evaluated. This performance depends on the complexity of the problem to be solved, the error allowance function, the dominance relation, and the search strategies. The exact performance may be difficult to predict due to the nondeterminism and anomalies of parallelism. The authors derive the performance bounds of parallel OR-tree searches with respect to the best-first, depth-first, and breadth-first strategies, and verify these bounds by simulation. They show that a near-linear speedup can be achieved with respect to a large number of processors for parallel OR-tree searches. Using the bounds developed, the authors derive sufficient conditions for assuring that parallelism will not degrade performance and necessary conditions for allowing parallelism to have a speedup greater than the ratio of the numbers of processors. These bounds and conditions provide the theoretical foundation for determining the number of processors required to assure a near-linear speedup.
Parallel Breadth-First Search LTL Model-Checking
Jir Barnat Lubos
2003-01-01
Abstract: We propose a practical parallel on-the-fly algorithm forenumerative LTL model-checking. The algorithm is designedfor a cluster of workstations communicating viaMPI. The detection of cycles (faulty runs) effectively employsthe so called back-level edges. In particular, a parallellevel-synchronized breadth-first search of the graph isperformed to discover back-level edges. For each level theback-level edges are checked in parallel by a nested depthfirstsearch
Multi-directional local search
Tricoire, Fabien
2012-01-01
This paper introduces multi-directional local search, a metaheuristic for multi-objective optimization. We first motivate the method and present an algorithmic framework for it. We then apply it to several known multi-objective problems such as the multi-objective multi-dimensional knapsack problem, the bi-objective set packing problem and the bi-objective orienteering problem. Experimental results show that our method systematically provides solution sets of comparable quality with state-of-the-art methods applied to benchmark instances of these problems, within reasonable CPU effort. We conclude that the proposed algorithmic framework is a viable option when solving multi-objective optimization problems. PMID:25140071
Multi-directional local search.
Tricoire, Fabien
2012-12-01
This paper introduces multi-directional local search, a metaheuristic for multi-objective optimization. We first motivate the method and present an algorithmic framework for it. We then apply it to several known multi-objective problems such as the multi-objective multi-dimensional knapsack problem, the bi-objective set packing problem and the bi-objective orienteering problem. Experimental results show that our method systematically provides solution sets of comparable quality with state-of-the-art methods applied to benchmark instances of these problems, within reasonable CPU effort. We conclude that the proposed algorithmic framework is a viable option when solving multi-objective optimization problems. PMID:25140071
Parallel/distributed direct method for solving linear systems
NASA Technical Reports Server (NTRS)
Lin, Avi
1990-01-01
A new family of parallel schemes for directly solving linear systems is presented and analyzed. It is shown that these schemes exhibit a near optimal performance and enjoy several important features: (1) For large enough linear systems, the design of the appropriate paralleled algorithm is insensitive to the number of processors as its performance grows monotonically with them; (2) It is especially good for large matrices, with dimensions large relative to the number of processors in the system; (3) It can be used in both distributed parallel computing environments and tightly coupled parallel computing systems; and (4) This set of algorithms can be mapped onto any parallel architecture without any major programming difficulties or algorithmical changes.
ALTERNATING DIRECTION APPROXIMATE NEWTON METHOD FOR PARTIALLY PARALLEL IMAGING
Zhang, Hongchao
-space; this reduces acquisition time, increases temporal/spatial resolution, and suppresses motion-related artifacts in magnetic resonance imaging applications [15, 16, 23]. The reduced data set leads to aliasing artifacts. Partially parallel imag- ing (PPI) acquires a reduced data set in the phase encoding direction(s) of k
OPTIMIZATION BY DIRECT SEARCH IN MATRIX COMPUTATIONS
NICHOLAS J. HIGHAMt
1993-01-01
A direct search method attempts to maximize a function f l R using function values only. Many questions about the stability and accuracy of algorithms in matrix computations can be expressed in terms of the maximum value ofsome easily computable function f. For a variety of algorithms it is shown that direct search is capable of revealing instability or poor
Series-parallel method of direct solar array regulation
NASA Technical Reports Server (NTRS)
Gooder, S. T.
1976-01-01
A 40 watt experimental solar array was directly regulated by shorting out appropriate combinations of series and parallel segments of a solar array. Regulation switches were employed to control the array at various set-point voltages between 25 and 40 volts. Regulation to within + or - 0.5 volt was obtained over a range of solar array temperatures and illumination levels as an active load was varied from open circuit to maximum available power. A fourfold reduction in regulation switch power dissipation was achieved with series-parallel regulation as compared to the usual series-only switching for direct solar array regulation.
PLAST: parallel local alignment search tool for database comparison
Nguyen, Van Hoa; Lavenier, Dominique
2009-01-01
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. PMID:19821978
Parallel Breadth-First Search LTL Model-Checking
Jir ´ i Barnat; Lubos Brim; Jakub Chaloupka
2003-01-01
We propose a practical parallel on-the-fly algorithm for enumerative LTL model-checking. The algorithm is de- signed for a cluster of workstations communicating via MPI. The detection of cycles (faulty runs) effectively em- ploys the so called back-level edges. In particular, a par- allel level-synchronized breadth-first search of the graph is performed to discover back-level edges. For each level the back-level
Direct and indirect searches for New Physics
F. Mahmoudi
2012-05-23
An overview of the indirect constraints from flavour physics on supersymmetric models is presented. We study in particular constraints from Bs -> mu+mu- and B -> K* mu+mu-, emphasising on the new LHCb results. We show that these rare transitions provide valuable information in the search for new physics and are complementary to the direct searches.
J. Parallel Distrib. Comput. 70 (2010) 270281 Contents lists available at ScienceDirect
Torres-Verdín, Carlos
2010-01-01
J. Parallel Distrib. Comput. 70 (2010) 270281 Contents lists available at ScienceDirect J. Parallel Distrib. Comput. journal homepage: www.elsevier.com/locate/jpdc A parallel direct solver 2009 Keywords: Parallel direct solvers Finite Element Method hp adaptivity 3D borehole resistivity a b
Combining search directions using gradient flows
Javier M. Moguerza; Francisco J. Prieto
2003-01-01
. ?The efficient combination of directions is a significant problem in line search methods that either use negative curvature,\\u000a or wish to include additional information such as the gradient or different approximations to the Newton direction. \\u000a \\u000a In this paper we describe a new procedure to combine several of these directions within an interior-point primal-dual algorithm.\\u000a Basically, we combine in an efficient
Fast parallel tandem mass spectral library searching using GPU hardware acceleration
Baumgardner, Lydia Ashleigh; Shanmugam, Avinash Kumar; Lam, Henry; Eng, Jimmy K.; Martin, Daniel B.
2011-01-01
Mass spectrometry-based proteomics is a maturing discipline of biologic research that is experiencing substantial growth. Instrumentation has steadily improved over time with the advent of faster and more sensitive instruments collecting ever larger data files. Consequently, the computational process of matching a peptide fragmentation pattern to its sequence, traditionally accomplished by sequence database searching and more recently also by spectral library searching, has become a bottleneck in many mass spectrometry experiments. In both of these methods, the main rate limiting step is the comparison of an acquired spectrum with all potential matches from a spectral library or sequence database. This is a highly parallelizable process because the core computational element can be represented as a simple but arithmetically intense multiplication of two vectors. In this paper we present a proof of concept project taking advantage of the massively parallel computing available on graphics processing units (GPUs) to distribute and accelerate the process of spectral assignment using spectral library searching. This program, which we have named FastPaSS (for Fast Parallelized Spectral Searching) is implemented in CUDA (Compute Unified Device Architecture) from NVIDIA which allows direct access to the processors in an NVIDIA GPU. Our efforts demonstrate the feasibility of GPU computing for spectral assignment, through implementation of the validated spectral searching algorithm SpectraST in the CUDA environment. PMID:21545112
Revisiting constraint-directed search
Magnus Ågren; Pierre Flener; Justin Pearson
2009-01-01
We revisit the exploration of constraint-directed neighbour- hoods, where a (small) set of constraints is picked before considering the neighbouring configurations where those constraints have a decreased (or preserved, or increased) penalty. Given the semantics of a constraint, such neighbourhoods can be represented via new attributes or primi- tives for the corresponding constraint object. We show how to define these
Panel on future directions in parallel computer architecture
VanTilborg, A.M. (Office of Naval Research, Arlington, VA (USA))
1989-06-01
One of the program highlights of the 15th Annual International Symposium on Computer Architecture, held May 30 - June 2, 1988 in Honolulu, was a panel session on future directions in parallel computer architecture. The panel was organized and chaired by the author, and was comprised of Prof. Jack Dennis (NASA Ames Research Institute for Advanced Computer Science), Prof. H.T. Kung (Carnegie Mellon), and Dr. Burton Smith (Tera Computer Company). The objective of the panel was to identify the likely trajectory of future parallel computer system progress, particularly from the sandpoint of marketplace acceptance. Approximately 250 attendees participated in the session, in which each panelist began with a ten minute viewgraph explanation of his views, followed by an open and sometimes lively exchange with the audience and fellow panelists. The session ran for ninety minutes.
Exploiting Parallelism to Accelerate Keyword Search on Deep-Web Sources
Tantan Liu; Fan Wang; Gagan Agrawal
2009-01-01
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.
Blocksome, Michael A; Mamidala, Amith R
2014-02-11
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
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.
Bermingham, Eldredge
Visual Motion-Detection Circuits in Flies: Parallel Direction- and Non-Direction-Sensitive Pathways into parallel retinotopic pathways that subsequently are reunited at higher levels. In insects, achromatic to the lobula. Further parallel subdivisions of the retinotopic pathways to the lobula plate have been suggested
Direct searches for dark matter: recent results.
Rosenberg, L J
1998-01-01
There is abundant evidence for large amounts of unseen matter in the universe. This dark matter, by its very nature, couples feebly to ordinary matter and is correspondingly difficult to detect. Nonetheless, several experiments are now underway with the sensitivity required to detect directly galactic halo dark matter through their interactions with matter and radiation. These experiments divide into two broad classes: searches for weakly interacting massive particles (WIMPs) and searches for axions. There exists a very strong theoretical bias for supposing that supersymmetry (SUSY) is a correct description of nature. WIMPs are predicted by this SUSY theory and have the required properties to be dark matter. These WIMPs are detected from the byproducts of their occasional recoil against nucleons. There are efforts around the world to detect these rare recoils. The WIMP part of this overview focuses on the cryogenic dark matter search (CDMS) underway in California. Axions, another favored dark matter candidate, are predicted to arise from a minimal extension of the standard model that explains the absence of the expected large CP violating effects in strong interactions. Axions can, in the presence of a large magnetic field, turn into microwave photons. It is the slight excess of photons above noise that signals the axion. Axion searches are underway in California and Japan. The axion part of this overview focuses on the California effort. Brevity does not allow me to discuss other WIMP and axion searches, likewise for accelerator and satellite based searches; I apologize for their omission. PMID:9419325
Exploiting Parallelism to Accelerate Keyword Search On Deep-web Sources
Agrawal, Gagan
Exploiting Parallelism to Accelerate Keyword Search On Deep-web Sources Tantan Liu Fan Wang Gagan,wangfa,agrawal}@cse.ohio-state.edu Abstract. Increasingly, biological data is being shared over the deep web. Many biological queries can only that exploits parallelization for accelerating search over multiple deep web data sources. An interactive, two
Exact Quantum Search by Parallel Unitary Discrimination Schemes
Xiaodi Wu; Runyao Duan
2008-06-09
We study the unsorted database search problem with items $N$ from the viewpoint of unitary discrimination. Instead of considering the famous $O(\\sqrt{N})$ Grover's the bounded-error algorithm for the original problem, we seek for the results about the exact algorithms, i.e. the ones succeed with certainty. Under the standard oracle model $\\sum_j (-1)^{\\delta_{\\tau j}}|j>< j|$, we demonstrate a tight lower bound ${2/3}N+o(N)$ of the number of queries for any parallel scheme with unentangled input states. With the assistance of entanglement, we obtain a general lower bound ${1/2}(N-\\sqrt{N})$. We provide concrete examples to illustrate our results. In particular, we show that the case of N=6 can be solved exactly with only two queries by using a bipartite entangled input state. Our results indicate that in the standard oracle model the complexity of exact quantum search with one unique solution can be strictly less than that of the calculation of OR function.
Bs ->mu+ mu- versus Direct Higgs Searches
Chung Kao; Yili Wang
2006-10-31
We investigate the prospects for the discovery of neutral Higgs bosons with muons by direct searches at the CERN Large Hadron Collider (LHC) as well as by indirect searches in the rare decay Bs -> mu+ mu- at the Fermilab Tevatron and the LHC. Promising results have been found for the minimal supersymmetric standard model, the minimal supergravity (mSUGRA) model, and supergravity models with non-universal Higgs masses (NUHM SUGRA). For tanb \\simeq 50, we find that (i) the contours for a branching fraction of B(Bs -> mu+ mu-) = 1x10^{-8} in the parameter space are very close to the 5\\sigma contours for pp -> b \\phi^0 -> b mu+ mu- + X, \\phi^0 = h^0, H^0, A^0 at the LHC with an integrated luminosity (L) of 30 fb^{-1},(ii) the regions covered by B(Bs -> mu+ mu-) \\ge 5x10^{-9} and the discovery region for b\\phi^0 -> b mu+ mu- with 300 fb^{-1} are complementary in the mSUGRA parameter space,(iii) in NUHM SUGRA models, a discovery of B(Bs -> mu+ mu-) \\simeq 5x10^{-9} at the LHC will cover regions of the parameter space beyond the direct search for pp -> b\\phi^0 -> b mu+ mu- with L = 300 fb^{-1}.
Oriented modulation for watermarking in direct binary search halftone images.
Guo, Jing-Ming; Su, Chang-Cheng; Liu, Yun-Fu; Lee, Hua; Lee, Jiann-Der
2012-09-01
In this paper, a halftoning-based watermarking method is presented. This method enables high pixel-depth watermark embedding, while maintaining high image quality. This technique is capable of embedding watermarks with pixel depths up to 3 bits without causing prominent degradation to the image quality. To achieve high image quality, the parallel oriented high-efficient direct binary search (DBS) halftoning is selected to be integrated with the proposed orientation modulation (OM) method. The OM method utilizes different halftone texture orientations to carry different watermark data. In the decoder, the least-mean-square-trained filters are applied for feature extraction from watermarked images in the frequency domain, and the naïve Bayes classifier is used to analyze the extracted features and ultimately to decode the watermark data. Experimental results show that the DBS-based OM encoding method maintains a high degree of image quality and realizes the processing efficiency and robustness to be adapted in printing applications. PMID:22581134
A directed search for extraterrestrial laser signals
NASA Technical Reports Server (NTRS)
Betz, A.
1991-01-01
The focus of NASA's Search for Extraterrestrial Intelligence (SETI) Program is on microwave frequencies, where receivers have the best sensitivities for the detection of narrowband signals. Such receivers, when coupled to existing radio telescopes, form an optimal system for broad area searches over the sky. For a directed search, however, such as toward specific stars, calculations show that infrared wavelengths can be equally as effective as radio wavelengths for establishing an interstellar communication link. This is true because infrared telescopes have higher directivities (gains) that effectively compensate for the lower sensitivities of infrared receivers. The result is that, for a given level of transmitted power, the signal to noise ratio for communications is equally as good at infrared and radio wavelengths. It should also be noted that the overall sensitivities of both receiver systems are quite close to their respective fundamental limits: background thermal noise for the radio frequency system and quantum noise for the infrared receiver. Consequently, the choice of an optimum communication frequency may well be determined more by the achievable power levels of transmitters rather than the ultimate sensitivities of receivers at any specific frequency. In the infrared, CO2 laser transmitters with power levels greater than 1 MW can already be built on Earth. For a slightly more advanced civilization, a similar but enormously more powerful laser may be possible using a planetary atmosphere rich in CO2. Because of these possibilities and our own ignorance of what is really the optimum search frequency, a search for narrowband signals at infrared frequencies should be a part of a balanced SETI Program. Detection of narrowband infrared signals is best done with a heterodyne receiver functionally identical to a microwave spectral line receiver. We have built such a receiver for the detection of CO2 laser radiation at wavelengths near 10 microns. The spectrometer uses a high-speed HgCdTe diode as the photomixer and a small CO2 laser as the local oscillator. Output signals in the intermediate frequency range 0.1-2.6 GHz are processed by a 1000-channel acousto-optic signal processor. The receiver is being used on a 1.5-m telescope on Mt. Wilson to survey a selected sample of 150 nearby stars. The current status of the work is discussed along with future project plans.
Sussex Direct: Email Aliases IT Services Searching for Groups
Sussex, University of
Sussex Direct: Email Aliases IT Services Searching for Groups To access email aliases maintained Direct using your username and email password 2. Click the Admin tab at the top of the Sussex Direct Page 3. Click on the Email Aliases sub-tab. 4. To search for a specific alias, type in the email Alias
A Dynamic Load-Balancing Parallel Search for Enumerative Robot Path Planning
Babak Taati; Michael A. Greenspan; Kamal Gupta
2006-01-01
We present a parallel formulation for enumerative search in high dimensional spaces and apply it to planning paths for a 6-dof manipulator robot. Participating processors perform local A* search towards the goal configuration. To exploit all the processors at their maximum capacity at all times, a dynamic load-balancing scheme matches idle and busy processors for load transfer. For comparison purposes,
PNBA*: A Parallel Bidirectional Heuristic Search Algorithm Luis Henrique Oliveira Rios1
Chaimowicz, Luiz
PNBA*: A Parallel Bidirectional Heuristic Search Algorithm Luis Henrique Oliveira Rios1 , Luiz Chaimowicz1 1 Departamento de Ci^encia da Computac¸~ao Universidade Federal de Minas Gerais (UFMG) Belo Horizonte, MG Brasil {lhrios,chaimo}@dcc.ufmg.br Abstract. A* (A-star) is a heuristic search algorithm
In search of sweet-spots in parallel performance monitoring
Aroon Nataraj; Allen D. Malony; Allen Morris; Dorian C. Arnold; Barton P. Miller
2008-01-01
Parallel performance monitoring extends parallel measurement systems with infrastructure and interfaces for online performance data access, communication, and analysis. At the same time it raises concerns for the impact on application execution from monitor overhead. The application monitoring scheme parameterized by performance events to monitor, access frequency and the type of data analysis operation defines a set of monitoring requirements.
M. Govett; L. Hart; T. Henderson; J. Middlecoff; D. Schaffer
2003-01-01
A directive-based parallelization tool called the Scalable Modeling System (SMS) is described. The user inserts directives in the form of comments into existing Fortran code. SMS translates the code and directives into a parallel version that runs efficiently on shared and distributed memory high-performance computing platforms including the SGI Origin, IBM SP2, Cray T3E, Sun, and Alpha and Intel clusters.
Extended Aperture 2-D Direction Finding With a Two-Parallel-Shape-Array Using Propagator Method
Jin He; Zhong Liu
2009-01-01
In this letter, we propose a two-parallel-shape array geometry, consisting of sensors spaced much farther apart than a half-wavelength, to improve estimation accuracy via aperture extension for two-dimensional (2D) direction finding. First, the subarray parallel with the x-axis is employed to extract automatically paired high-variance but unambiguous y-axis direction cosines and low-variance but cyclically ambiguous x-axis direction cosines. Then, the
Taku Fukushima; Takashi Yoshino; Aguri Shigeno
2011-01-01
In this study, we have proposed an extraction method for inaccurate example sentences using a Web search engine for multilingual parallel texts. We developed a mul- tilingual parallel-text sharing system named TackPad for multilingual communication in the medical field. However, it should be noted that parallel texts created by people can be inaccurate. Hence, we cannot use these parallel texts
GRAPES: A Software for Parallel Searching on Biological Graphs Targeting Multi-Core Architectures
Bombieri, Nicola; Pulvirenti, Alfredo; Ferro, Alfredo; Shasha, Dennis
2013-01-01
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
Direct Observation of Localized Parallel Electric Fields in a Space Plasma
Ergun, R. E.; Su, Y.-J.; Andersson, L.; Carlson, C. W.; McFadden, J. P.; Mozer, F. S.; Newman, D. L.; Goldman, M. V.; Strangeway, R. J.
2001-07-23
We report direct measurements of parallel electric fields related to particle acceleration in a collisionless space plasma. The electric field is that of a monotonic potential ramp localized to {approx}10 debye lengths along the magnetic field. Electrons accelerated by the parallel electric field are accompanied by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes.
Mesh Adaptive Direct Search Algorithms for Constrained Optimization
Charles Audet; J. E. Dennis Jr.
2006-01-01
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
Matching and searching analysis for parallel hardware implementation on FPGAs
Pablo Moisset; Pedro C. Diniz
2001-01-01
Matching and searching computations play an important role in the indexing of data. These computations are typically encoded in very tight loops with a single index variable and a simple search\\/ matching predicate. Their inherent sequential nature, either because of data dependences but more often because of very strong control dependences, makes it impossible to apply existing data dependence and
Enabling Rapid Development of Parallel Tree Search Applications
Jeffrey P. Gardner; Andrew Connolly; Cameron McBride
2007-09-12
Virtual observatories will give astronomers easy access to an unprecedented amount of data. Extracting scientific knowledge from these data will increasingly demand both efficient algorithms as well as the power of parallel computers. Nearly all efficient analyses of large astronomical datasets use trees as their fundamental data structure. Writing efficient tree-based techniques, a task that is time-consuming even on single-processor computers, is exceedingly cumbersome on massively parallel platforms (MPPs). Most applications that run on MPPs are simulation codes, since the expense of developing them is offset by the fact that they will be used for many years by many researchers. In contrast, data analysis codes change far more rapidly, are often unique to individual researchers, and therefore accommodate little reuse. Consequently, the economics of the current high-performance computing development paradigm for MPPs does not favor data analysis applications. We have therefore built a library, called Ntropy, that provides a flexible, extensible, and easy-to-use way of developing tree-based data analysis algorithms for both serial and parallel platforms. Our experience has shown that not only does our library save development time, it can also deliver excellent serial performance and parallel scalability. Furthermore, Ntropy makes it easy for an astronomer with little or no parallel programming experience to quickly scale their application to a distributed multiprocessor environment. By minimizing development time for efficient and scalable data analysis, we enable wide-scale knowledge discovery on massive datasets.
APPSPACK 4.0 : asynchronous parallel pattern search for derivative-free optimization.
Gray, Genetha Anne; Kolda, Tamara Gibson
2004-12-01
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.
Ames testing of Direct Black 38 parallels carcinogenicity testing.
Gregory, A R; Elliott, J; Kluge, P
1981-12-01
Studies have established that Direct Black 38 and two other benzidine-based dyes are carcinogenic. The carcinogenic effect has been generally considered attributable to the metabolic release of benzidine from Direct Black 38 and similar dyes. However, Ames tests indicated that when Direct Black 38 is reduced with sodium dithionate it is more mutagenic than can be accounted for by complete release of all the benzidine present in the dye molecule. While most dyes are not mutagenic when tested with S-9, a series of benzidine congener dyes were all found to be mutagenic with either TA 98 or TA 100 strains, if the dyes were first reduced with sodium dithionate. Unreduced dyes were not mutagenic. Neither anaerobic conditions nor addition of riboflavin induced mutagenicity of these dyes under the condition of our experiments. PMID:6764474
Astronomical guidance for directed searches for continuous gravitational waves
NASA Astrophysics Data System (ADS)
Owen, Benjamin
2014-01-01
The LIGO Scientic Collaboration and Virgo Collaboration have published a search for continuous gravitational-waves from the non-pulsing neutron star in supernova remnant Cas A and, more recently, from the galactic center. More such searches, where the direction is known but no pulsar timing is available, are under way. I describe the astronomical criteria for good targets for such gravitational-wave searches, list classes of astronomical objects, and give examples of each class.
Parallel Multi-Swarm Optimization Framework for Search Problems in Water Distribution Systems
Parallel Multi-Swarm Optimization Framework for Search Problems in Water Distribution Systems Sarat concurrent particle swarms is developed and applied to water distribution problems. Details of the enabling characterization problems for two water distribution networks with 1,834 and 12,457 nodes respectively. 1
Cunning Ant System for Quadratic Assignment Problem with Local Search and Parallelization
Tsutsui, Shigeyoshi
Cunning Ant System for Quadratic Assignment Problem with Local Search and Parallelization. The previously proposed cunning ant system (cAS), a vari- ant of the ACO algorithm, worked well on the TSP have proposed a variant of the ACO algorithm called the cunning Ant System (cAS) and evaluated it using
APPSPACK 4.0 : asynchronous parallel pattern search for derivative-free optimization
Genetha Anne Gray; Tamara Gibson Kolda
2004-01-01
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
Parallel architectures for 3-step hierarchical search block-matching algorithm
Her-Ming Jong; Liang-Gee; Tzi-Dar Chiueh
1994-01-01
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
Paris-Sud XI, Université de
,artigues,lopez}@laas.fr Keywords: Parallel machine scheduling, setup times, precedence constraints, limited discrepancy search times, considered when dierents jobs are sequenced on the same machine, must be respected machine. The machine can process no more than one job at a time. The decision variables of the problem
Phase and chemical equilibrium calculations by direct search optimization
Yeow Peng Lee; Gade Pandu Rangaiah; Rein Luus
1999-01-01
Direct search optimization is applied to Gibbs free energy minimization to determine phase compositions at equilibrium. The method selected is the random search optimization procedure of Luus and Jaakola, which has been shown to be successful for solving difficult global optimization problems. It is implemented in a multipass fashion where the region size for a variable at the beginning of
Performance analysis of parallel branch and bound search with the hypercube architecture
NASA Technical Reports Server (NTRS)
Mraz, Richard T.
1987-01-01
With the availability of commercial parallel computers, researchers are examining new classes of problems which might benefit from parallel computing. This paper presents results of an investigation of the class of search intensive problems. The specific problem discussed is the Least-Cost Branch and Bound search method of deadline job scheduling. The object-oriented design methodology was used to map the problem into a parallel solution. While the initial design was good for a prototype, the best performance resulted from fine-tuning the algorithm for a specific computer. The experiments analyze the computation time, the speed up over a VAX 11/785, and the load balance of the problem when using loosely coupled multiprocessor system based on the hypercube architecture.
Gevorg Poghosyan; Sanchit Matta; Achim Streit; Micha? Bejger; Andrzej Królak
2014-10-14
The parallelization, design and scalability of the \\sky code to search for periodic gravitational waves from rotating neutron stars is discussed. The code is based on an efficient implementation of the F-statistic using the Fast Fourier Transform algorithm. To perform an analysis of data from the advanced LIGO and Virgo gravitational wave detectors' network, which will start operating in 2015, hundreds of millions of CPU hours will be required - the code utilizing the potential of massively parallel supercomputers is therefore mandatory. We have parallelized the code using the Message Passing Interface standard, implemented a mechanism for combining the searches at different sky-positions and frequency bands into one extremely scalable program. The parallel I/O interface is used to escape bottlenecks, when writing the generated data into file system. This allowed to develop a highly scalable computation code, which would enable the data analysis at large scales on acceptable time scales. Benchmarking of the code on a Cray XE6 system was performed to show efficiency of our parallelization concept and to demonstrate scaling up to 50 thousand cores in parallel.
Constraint-directed Search in Computational Finance and Economics
St Andrews, University of
Constraint-directed Search in Computational Finance and Economics Edward Tsang Centre for Computational Intelligence in Finance & Economics (CCFEA) University of Essex, Colchester, UK edward local optima. GGA uses the GLS penalty scheme to change the behaviour of genetic algorithms
A GPU based implementation of direct multi-bit search (DMS) screen algorithm
NASA Astrophysics Data System (ADS)
Trager, Barry; Chandu, Kartheek; Wu, Chai Wah; Stanich, Mikel
2013-02-01
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.
iPRIDE: a parallel integrated circuit simulator using direct method
Mi-Chang Chang; I. N. Hajj
1988-01-01
A parallel circuit simulator, iPRIDE, which uses a direct solution method and runs on a shared-memory multiprocessor is described. The simulator is based on a multilevel node tearing approach which produces a nested bordered-block-diagonal (BBD) form of the circuit equation matrix. The parallel solution of the nested BBD matrix is described. Its efficiency is shown to depend on how the
A directed search for extraterrestrial laser signals.
Betz, A
1986-01-01
This paper analyzes the technical feasibility of interstellar communication at infrared frequencies, both in its own right and in comparison with communication at radio frequencies. The analysis considers both the practical and fundamental limits affecting communication over interstellar distances and concludes that for specified transmitter and receiver locations communications at infrared and radio frequencies can be equally effective. On this basis a search for extraterrestrial signals at infrared wavelengths is equally as valid as any planned microwave effort. Work is now in progress to adapt a 10 micrometers heterodyne spectrometer to search for CO2 laser signals from 200 nearby stars. PMID:11539667
A Parallel Framework for Multipoint Spiral Search in ab Initio Protein Structure Prediction
Rashid, Mahmood A.; Newton, M. A. Hakim; Hoque, Md Tamjidul; Sattar, Abdul
2014-01-01
Protein structure prediction is computationally a very challenging problem. A large number of existing search algorithms attempt to solve the problem by exploring possible structures and finding the one with the minimum free energy. However, these algorithms perform poorly on large sized proteins due to an astronomically wide search space. In this paper, we present a multipoint spiral search framework that uses parallel processing techniques to expedite exploration by starting from different points. In our approach, a set of random initial solutions are generated and distributed to different threads. We allow each thread to run for a predefined period of time. The improved solutions are stored threadwise. When the threads finish, the solutions are merged together and the duplicates are removed. A selected distinct set of solutions are then split to different threads again. In our ab initio protein structure prediction method, we use the three-dimensional face-centred-cubic lattice for structure-backbone mapping. We use both the low resolution hydrophobic-polar energy model and the high-resolution 20 × 20 energy model for search guiding. The experimental results show that our new parallel framework significantly improves the results obtained by the state-of-the-art single-point search approaches for both energy models on three-dimensional face-centred-cubic lattice. We also experimentally show the effectiveness of mixing energy models within parallel threads. PMID:24744779
High-performance parallel sparse-direct triangular solves (Invited)
NASA Astrophysics Data System (ADS)
Poulson, J.; Ying, L.
2013-12-01
Geophysical inverse problems are increasingly posed in the frequency domain in a manner which requires solving many challenging heterogeneous 3D Helmholtz or linear elastic wave equations at each iteration. One effective means of solving such problems, at least when there is no large-scale internal resonance, is to use moving-PML "sweeping preconditioners". Each application of the sweeping preconditioner involves performing many modest-sized sparse-direct triangular solves -- unfortunately, one at a time. While P. et al. have shown that, with a careful implementation of a distributed sparse-direct solver [1,2], challenging 3D problems approaching a billion degrees of freedom can be solved in a few minutes using less than 10,000 cores, this talk discusses how to leverage the existence of many right-hand sides in order to increase the performance of the preconditioner applications by orders of magnitude. [1] http://github.com/poulson/Clique [2] http://github.com/poulson/PSP
Chaimowicz, Luiz
Speeding Up Learning in Real-time Search through Parallel Computing Vinicius Marques Luiz, Brazil {allonman,chaimo,renato}@dcc.ufmg.br Abstract Real-time search algorithms solve the problem is solved repeatedly. However, performing search in a limited area due to real-time constraints makes
A direct search for Dirac magnetic monopoles
Mulhearn, Michael James
2005-01-01
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, ...
Simulating a Direction-Finder Search for an ELT
NASA Technical Reports Server (NTRS)
Bream, Bruce
2005-01-01
A computer program simulates the operation of direction-finding equipment engaged in a search for an emergency locator transmitter (ELT) aboard an aircraft that has crashed. The simulated equipment is patterned after the equipment used by the Civil Air Patrol to search for missing aircraft. The program is designed to be used for training in radio direction-finding and/or searching for missing aircraft without incurring the expense and risk of using real aircraft and ground search resources. The program places a hidden ELT on a map and enables the user to search for the location of the ELT by moving a 14 NASA Tech Briefs, March 2005 small aircraft image around the map while observing signal-strength and direction readings on a simulated direction- finding locator instrument. As the simulated aircraft is turned and moved on the map, the program updates the readings on the direction-finding instrument to reflect the current position and heading of the aircraft relative to the location of the ELT. The software is distributed in a zip file that contains an installation program. The software runs on the Microsoft Windows 9x, NT, and XP operating systems.
Two Quantum Direct Communication Protocols Based on Quantum Search Algorithm
NASA Astrophysics Data System (ADS)
Xu, Shu-Jiang; Chen, Xiu-Bo; Wang, Lian-Hai; Niu, Xin-Xin; Yang, Yi-Xian
2014-12-01
Based on the properties of two-qubit Grover's quantum search algorithm, we propose two quantum direct communication protocols, including a deterministic secure quantum communication and a quantum secure direct communication protocol. Secret messages can be directly sent from the sender to the receiver by using two-qubit unitary operations and the single photon measurement with one of the proposed protocols. Theoretical analysis shows that the security of the proposed protocols can be highly ensured.
Two Quantum Direct Communication Protocols Based on Quantum Search Algorithm
NASA Astrophysics Data System (ADS)
Xu, Shu-Jiang; Chen, Xiu-Bo; Wang, Lian-Hai; Niu, Xin-Xin; Yang, Yi-Xian
2015-07-01
Based on the properties of two-qubit Grover's quantum search algorithm, we propose two quantum direct communication protocols, including a deterministic secure quantum communication and a quantum secure direct communication protocol. Secret messages can be directly sent from the sender to the receiver by using two-qubit unitary operations and the single photon measurement with one of the proposed protocols. Theoretical analysis shows that the security of the proposed protocols can be highly ensured.
California at Berkeley, University of
Parallel electric fields in the upward current region of the aurora: Indirect and direct current region of the aurora focusing on the structure of electric fields at the boundary between account of the electric fields in the upward current region of the aurora as observed by the Fast Auroral
A bidirectional data driven lisp engine for the direct execution of lisp in parallel
Yen, C.K.; Wong, W.F. (Dept. of Information Systems and Computer Science, National Univ. of Singapore, Kent Ridge (SG))
1989-06-01
This article gives a brief introduction to BIDDLE. The authors' aim here is to argue that the basic principle of BIDDLE are quite straightforward and that they can, indeed, design an architecture to directly execute Lisp in parallel. As mentioned in the introduction, important and interesting issues like side effect handling, object storage, environment maintenance etc. are not dealt with in great enough details.
Haibo Dong
2003-01-01
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
Direct Search for Low Mass Dark Matter Particles with CCDs
Barreto, J [Rio de Janeiro Federal U.; Cease, H.; Diehl, H.T.; Estrada, J.; Flaugher, B.; Harrison, N.; Jones, J.; Kilminster, B [Fermilab; Molina, J [Asuncion Natl. U.; Smith, J.; Sonnenschein, A [Fermilab
2012-05-15
A direct dark matter search is performed using fully-depleted high-resistivity CCD detectors. Due to their low electronic readout noise (RMS ~7 eV) these devices operate with a very low detection threshold of 40 eV, making the search for dark matter particles with low masses (~5 GeV) possible. The results of an engineering run performed in a shallow underground site are presented, demonstrating the potential of this technology in the low mass region.
Nonsmooth optimization through Mesh Adaptive Direct Search and Variable Neighborhood Search
Charles Audet; Vincent Béchard; Sébastien Le Digabel
2008-01-01
This paper proposes a way to combine the Mesh Adaptive Direct Search (MADS) algorithm, which extends the Generalized Pattern\\u000a Search (GPS) algorithm, with the Variable Neighborhood Search (VNS) metaheuristic, for nonsmooth constrained optimization.\\u000a The resulting algorithm retains the convergence properties of MADS, and allows the far reaching exploration features of VNS\\u000a to move away from local solutions. The paper also
Virtual parallel computing and a search algorithm using matrix product states.
Chamon, Claudio; Mucciolo, Eduardo R
2012-07-20
We propose a form of parallel computing on classical computers that is based on matrix product states. The virtual parallelization is accomplished by representing bits with matrices and by evolving these matrices from an initial product state that encodes multiple inputs. Matrix evolution follows from the sequential application of gates, as in a logical circuit. The action by classical probabilistic one-bit and deterministic two-bit gates such as NAND are implemented in terms of matrix operations and, as opposed to quantum computing, it is possible to copy bits. We present a way to explore this method of computation to solve search problems and count the number of solutions. We argue that if the classical computational cost of testing solutions (witnesses) requires less than O(n2) local two-bit gates acting on n bits, the search problem can be fully solved in subexponential time. Therefore, for this restricted type of search problem, the virtual parallelization scheme is faster than Grover's quantum algorithm. PMID:22861832
Searching for a perceived gaze direction using eye tracking
Palanica, Adam; Itier, Roxane J.
2014-01-01
The purpose of the current study was to use eye tracking to better understand the “stare-in-the-crowd effect”—the notion that direct gaze is more easily detected than averted gaze in a crowd of opposite-gaze distractors. Stimuli were displays of four full characters aligned across the monitor (one target and three distractors). Participants completed a visual search task in which they were asked to detect the location of either a direct gaze or an averted gaze target. Reaction time (RT) results indicated faster responses to direct than averted gaze only for characters situated in the far peripheral visual fields. Eye movements confirmed a serial search strategy (definitely ruling out any pop-out effects) and revealed different exploration patterns between hemifields. The latency before the first fixation on target strongly correlated with response RTs. In the LVF, that latency was also faster for direct than averted gaze targets, suggesting that the response asymmetry in favor of direct gaze stemmed from faster direct gaze target detection. In the RVF, however, the response bias to direct gaze seemed not due to a faster visual detection but rather to a different cognitive mechanism. Direct gaze targets were also responded to even faster when their position was congruent with the direction of gaze of distractors. These findings suggest that the detection asymmetry for direct gaze is highly dependent on target position and influenced by social contexts. PMID:21367758
A Direct Search for Dirac Magnetic Monopoles
Mulhearn, Michael James
2004-10-01
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.
Physician Assistant Self-Directed Search Holland Codes
ERIC Educational Resources Information Center
LaBarbera, Dawn M.
2005-01-01
A mailed survey was used to identify the vocational interests of physician assistants (PAs) as measured by Holland's Self-Directed Search (SDS) Form R. A random sample of 2,323 PAs from the American Academy of Physician Assistants' mailing list was sent a survey to identify a pool of practicing PAs satisfied with their career choices for further…
A direct-execution parallel architecture for the Advanced Continuous Simulation Language (ACSL)
NASA Technical Reports Server (NTRS)
Carroll, Chester C.; Owen, Jeffrey E.
1988-01-01
A direct-execution parallel architecture for the Advanced Continuous Simulation Language (ACSL) is presented which overcomes the traditional disadvantages of simulations executed on a digital computer. The incorporation of parallel processing allows the mapping of simulations into a digital computer to be done in the same inherently parallel manner as they are currently mapped onto an analog computer. The direct-execution format maximizes the efficiency of the executed code since the need for a high level language compiler is eliminated. Resolution is greatly increased over that which is available with an analog computer without the sacrifice in execution speed normally expected with digitial computer simulations. Although this report covers all aspects of the new architecture, key emphasis is placed on the processing element configuration and the microprogramming of the ACLS constructs. The execution times for all ACLS constructs are computed using a model of a processing element based on the AMD 29000 CPU and the AMD 29027 FPU. The increase in execution speed provided by parallel processing is exemplified by comparing the derived execution times of two ACSL programs with the execution times for the same programs executed on a similar sequential architecture.
Parallel Directionally Split Solver Based on Reformulation of Pipelined Thomas Algorithm
NASA Technical Reports Server (NTRS)
Povitsky, A.
1998-01-01
In this research an efficient parallel algorithm for 3-D directionally split problems is developed. The proposed algorithm is based on a reformulated version of the pipelined Thomas algorithm that starts the backward step computations immediately after the completion of the forward step computations for the first portion of lines This algorithm has data available for other computational tasks while processors are idle from the Thomas algorithm. The proposed 3-D directionally split solver is based on the static scheduling of processors where local and non-local, data-dependent and data-independent computations are scheduled while processors are idle. A theoretical model of parallelization efficiency is used to define optimal parameters of the algorithm, to show an asymptotic parallelization penalty and to obtain an optimal cover of a global domain with subdomains. It is shown by computational experiments and by the theoretical model that the proposed algorithm reduces the parallelization penalty about two times over the basic algorithm for the range of the number of processors (subdomains) considered and the number of grid nodes per subdomain.
PoS(ICHEP2010)539 Dark Matter direct detection searches
Boyer, Edmond
PoS(ICHEP2010)539 Dark Matter direct detection searches Jules Gascon IPNL, Université de Lyon searches for Dark Matter is presented. These experi- ments look for energetic recoiling ions produced)539 Direct Searches for Dark Matter Jules Gascon Direct searches for Dark Matter in the form of Weakly
Mark K. Gardner; Wu-chun Feng; Jeremy S. Archuleta; Heshan Lin; Xiaosong Mal
2006-01-01
The Basic Local Alignment Search Tool (BLAST) allows bioinformaticists to characterize an unknown sequence by comparing it against a database of known sequences. The similarity between sequences enables biologists to detect evolutionary relationships and infer biological properties of the unknown sequence.mpiBLAST, our parallel BLAST, decreases the search time of a 300 KB query on the current NT database from over
Noncoherent Parallel Acquisition of Pn Sequences in Direct-Sequence Spread-Spectrum Systems
ANDREW M. SLONNEGER; DILIP V. SARWATE
1992-01-01
Noncoherent schemes fcm the acquisition of PN sequences in directsequence spread-spectrum systems are of interest because they can acquire the sequence even before the carrier tracking loop achieves phase lock. On the other hand, such schemes have higher falselock probability than coherent acquisition schemes. Four different noncoherent schemes for the parallel acquisition of a PN sequence in a direct-sequence spread-spectrum
NASA Technical Reports Server (NTRS)
Lee, J.; Kim, K.
1991-01-01
A Very Large Scale Integration (VLSI) architecture for robot direct kinematic computation suitable for industrial robot manipulators was investigated. The Denavit-Hartenberg transformations are reviewed to exploit a proper processing element, namely an augmented CORDIC. Specifically, two distinct implementations are elaborated on, such as the bit-serial and parallel. Performance of each scheme is analyzed with respect to the time to compute one location of the end-effector of a 6-links manipulator, and the number of transistors required.
NASA Astrophysics Data System (ADS)
Lee, J.; Kim, K.
A Very Large Scale Integration (VLSI) architecture for robot direct kinematic computation suitable for industrial robot manipulators was investigated. The Denavit-Hartenberg transformations are reviewed to exploit a proper processing element, namely an augmented CORDIC. Specifically, two distinct implementations are elaborated on, such as the bit-serial and parallel. Performance of each scheme is analyzed with respect to the time to compute one location of the end-effector of a 6-links manipulator, and the number of transistors required.
Slepoy, A; Peters, M D; Thompson, A P
2007-11-30
Molecular dynamics and other molecular simulation methods rely on a potential energy function, based only on the relative coordinates of the atomic nuclei. Such a function, called a force field, approximately represents the electronic structure interactions of a condensed matter system. Developing such approximate functions and fitting their parameters remains an arduous, time-consuming process, relying on expert physical intuition. To address this problem, a functional programming methodology was developed that may enable automated discovery of entirely new force-field functional forms, while simultaneously fitting parameter values. The method uses a combination of genetic programming, Metropolis Monte Carlo importance sampling and parallel tempering, to efficiently search a large space of candidate functional forms and parameters. The methodology was tested using a nontrivial problem with a well-defined globally optimal solution: a small set of atomic configurations was generated and the energy of each configuration was calculated using the Lennard-Jones pair potential. Starting with a population of random functions, our fully automated, massively parallel implementation of the method reproducibly discovered the original Lennard-Jones pair potential by searching for several hours on 100 processors, sampling only a minuscule portion of the total search space. This result indicates that, with further improvement, the method may be suitable for unsupervised development of more accurate force fields with completely new functional forms. PMID:17565499
NASA Technical Reports Server (NTRS)
Morgan, Philip E.
2004-01-01
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 "Devleop High-Performance Time-Domain Computational Electromagnetics Capability for RCS Prediction, Wave Propagation in Dispersive Media, and Dual-Use Applications. The discussion of Scalable High Performance Computing reports on three objectives: validate, access scalability, and apply two parallel flow solvers for three-dimensional Navier-Stokes flows; develop and validate a high-order parallel solver for Direct Numerical Simulations (DNS) and Large Eddy Simulation (LES) problems; and Investigate and develop a high-order Reynolds averaged Navier-Stokes turbulence model. The discussion of High-Performance Time-Domain Computational Electromagnetics reports on five objectives: enhancement of an electromagnetics code (CHARGE) to be able to effectively model antenna problems; utilize lessons learned in high-order/spectral solution of swirling 3D jets to apply to solving electromagnetics project; transition a high-order fluids code, FDL3DI, to be able to solve Maxwell's Equations using compact-differencing; develop and demonstrate improved radiation absorbing boundary conditions for high-order CEM; and extend high-order CEM solver to address variable material properties. The report also contains a review of work done by the systems engineer.
Parallel implementation of 3D protein structure similarity searches using a GPU and the CUDA.
Mrozek, Dariusz; Bro?ek, Mi?osz; Ma?ysiak-Mrozek, Bo?ena
2014-02-01
Searching for similar 3D protein structures is one of the primary processes employed in the field of structural bioinformatics. However, the computational complexity of this process means that it is constantly necessary to search for new methods that can perform such a process faster and more efficiently. Finding molecular substructures that complex protein structures have in common is still a challenging task, especially when entire databases containing tens or even hundreds of thousands of protein structures must be scanned. Graphics processing units (GPUs) and general purpose graphics processing units (GPGPUs) can perform many time-consuming and computationally demanding processes much more quickly than a classical CPU can. In this paper, we describe the GPU-based implementation of the CASSERT algorithm for 3D protein structure similarity searching. This algorithm is based on the two-phase alignment of protein structures when matching fragments of the compared proteins. The GPU (GeForce GTX 560Ti: 384 cores, 2GB RAM) implementation of CASSERT ("GPU-CASSERT") parallelizes both alignment phases and yields an average 180-fold increase in speed over its CPU-based, single-core implementation on an Intel Xeon E5620 (2.40GHz, 4 cores). In this paper, we show that massive parallelization of the 3D structure similarity search process on many-core GPU devices can reduce the execution time of the process, allowing it to be performed in real time. GPU-CASSERT is available at: http://zti.polsl.pl/dmrozek/science/gpucassert/cassert.htm. PMID:24481593
Direct search methods in the optimisation of cancer chemotherapy regimens.
Berenbaum, M C
1990-01-01
Current cancer chemotherapy regimens may involve 20-30 or more independent variables, each affecting therapeutic response and toxicity. With standard response surface modelling methods, finding the optimum combination with as few as 10 variables entails testing over 1,000 combinations, so these methods do not provide a feasible approach to such problems. However, they may be tackled by direct search methods (DSM), i.e. stepwise searches of the response surface. Experiments were carried out in advanced L1210 leukaemia treated with combinations of adriamycin with cyclophosphamide, isophosphamide with acetylcysteine and methotrexate with leucovorin. Two established DSM (Nelder-Mead and Box) were used, and a new method was designed to find consistent search paths in spite of wide biological variation. With methotrexate and leucovorin, DSM located combinations prolonging mean survival to 40-50 days (compared with 10.4 in controls) and giving high proportions of long-term survivors. These results were achieved with single injections of drugs given 7 days after injection of 10(6) leukaemic cells, i.e. 2-3 days before deaths began in untreated mice, and appear to be unprecedented with these agents. Searching for optimal combinations of established agents may be at least as rewarding as searching for new agents, and thus DSM may prove a powerful tool for improving the results of combination cancer chemotherapy. PMID:2297481
Co-ordination of directional overcurrent protection with load current for parallel feeders
Wright, J.W.; Lloyd, G.; Hindle, P.J. [Alstom, Inc., Stafford (United Kingdom). T and D Protection and Control
1999-11-01
Directional phase overcurrent relays are commonly applied at the receiving ends of parallel feeders or transformer feeders. Their purpose is to ensure full discrimination of main or back-up power system overcurrent protection for a fault near the receiving end of one feeder. This paper reviews this type of relay application and highlights load current setting constraints for directional protection. Such constraints have not previously been publicized in well-known text books. A directional relay current setting constraint that is suggested in some text books is based purely on thermal rating considerations for older technology relays. This constraint may not exist with modern numerical relays. In the absence of any apparent constraint, there is a temptation to adopt lower current settings with modern directional relays in relation to reverse load current at the receiving ends of parallel feeders. This paper identifies the danger of adopting very low current settings without any special relay feature to ensure protection security with load current during power system faults. A system incident recorded by numerical relays is also offered to highlight this danger. In cases where there is a need to infringe the identified constraints an implemented and testing relaying technique is proposed.
Direct and Inverse Kinematics of a Novel Tip-Tilt-Piston Parallel Manipulator
NASA Technical Reports Server (NTRS)
Tahmasebi, Farhad
2004-01-01
Closed-form direct and inverse kinematics of a new three degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base-mounted; higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of tangent of half-angle between one of the limbs and the base plane. Hence, there are at most 16 assembly configurations for the manipulator. In addition, it is shown that the 16 solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented.
Yurovsky, Daniel; Yu, Chen; Smith, Linda B.
2012-01-01
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. PMID:23162487
A survey of search directions in interior point methods for linear programming
Dick Den Hertog; Cees Roos
1991-01-01
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 this report we derive explicit expressions for the search directions used in many well-known algorithms. Comparing these explicit expressions gives a good insight into the similarities and differences between
Jeong Ho Kim; Chang Sung Lee; Seung Jo Kim
2004-01-01
Most of researches for large-scale parallel structural analysis using finite element method have focused on iterative solution methods since direct solution methods generally have many difficulties and disadvantages for large-scale problems. However, due to the numerical robustness of direct methods that guarantees the solution to be obtained within estimated time, direct methods are much more desirable for general application of
Study of genetic direct search algorithms for function optimization
NASA Technical Reports Server (NTRS)
Zeigler, B. P.
1974-01-01
The results are presented of a study to determine the performance of genetic direct search algorithms in solving function optimization problems arising in the optimal and adaptive control areas. The findings indicate that: (1) genetic algorithms can outperform standard algorithms in multimodal and/or noisy optimization situations, but suffer from lack of gradient exploitation facilities when gradient information can be utilized to guide the search. (2) For large populations, or low dimensional function spaces, mutation is a sufficient operator. However for small populations or high dimensional functions, crossover applied in about equal frequency with mutation is an optimum combination. (3) Complexity, in terms of storage space and running time, is significantly increased when population size is increased or the inversion operator, or the second level adaptation routine is added to the basic structure.
Direct searches of extra Higgs boson at future colliders
Yokoya, Hiroshi
2015-01-01
We study direct searches of additional Higgs bosons in multi-top-quarks events at the LHC with the collision energy of 14 TeV as well as the International Linear Collider (ILC) with the collision energy of 1 TeV. As a benchmark model, we consider two Higgs doublet models with a softly-broken discrete $Z_2$ symmetry, where the $t\\bar t$ decay mode of additional neutral Higgs bosons can be dominant if their masses are heavy enough. Thus, the multi-top-quarks events become an important probe of the extended Higgs sector at future colliders. We estimate the discovery reach at the LHC and the ILC, and find that the search at the ILC can survey the parameter regions where the LHC cannot cover.
A direct search algorithm for optimization with noisy function evaluations
Anderson, E. [Univ. of Cambridge, MA (United States); Ferris, M.
1994-12-31
In this paper we describe a new direct search algorithm, reminiscent of the Nelder-Mead method, and related to a more recent pattern search algorithm proposed by Torczon. We believe that this method has applications in situations in which each function evaluation is noisy, but in which repeated function evaluations at the same point can be used to progressively reduce the error. For example, this will occur if the objective function value is given as a result of a simulation experiment. We investigate the convergence behaviour of the new algorithm for problems in which each function evaluation returns the true value of the function plus a random error drawn from a Normal distribution.
Effects of rotation on turbulent convection: Direct numerical simulation using parallel processors
NASA Astrophysics Data System (ADS)
Chan, Daniel Chiu-Leung
A new parallel implicit adaptive mesh refinement (AMR) algorithm is developed for the prediction of unsteady behaviour of laminar flames. The scheme is applied to the solution of the system of partial-differential equations governing time-dependent, two- and three-dimensional, compressible laminar flows for reactive thermally perfect gaseous mixtures. A high-resolution finite-volume spatial discretization procedure is used to solve the conservation form of these equations on body-fitted multi-block hexahedral meshes. A local preconditioning technique is used to remove numerical stiffness and maintain solution accuracy for low-Mach-number, nearly incompressible flows. A flexible block-based octree data structure has been developed and is used to facilitate automatic solution-directed mesh adaptation according to physics-based refinement criteria. The data structure also enables an efficient and scalable parallel implementation via domain decomposition. The parallel implicit formulation makes use of a dual-time-stepping like approach with an implicit second-order backward discretization of the physical time, in which a Jacobian-free inexact Newton method with a preconditioned generalized minimal residual (GMRES) algorithm is used to solve the system of nonlinear algebraic equations arising from the temporal and spatial discretization procedures. An additive Schwarz global preconditioner is used in conjunction with block incomplete LU type local preconditioners for each sub-domain. The Schwarz preconditioning and block-based data structure readily allow efficient and scalable parallel implementations of the implicit AMR approach on distributed-memory multi-processor architectures. The scheme was applied to solutions of steady and unsteady laminar diffusion and premixed methane-air combustion and was found to accurately predict key flame characteristics. For a premixed flame under terrestrial gravity, the scheme accurately predicted the frequency of the natural buoyancy induced oscillations. The performance of the proposed parallel implicit algorithm was assessed by comparisons to more conventional solution procedures and was found to significantly reduce the computational time required to achieve a solution in all cases investigated.
Guerdoux-Jamet, P; Risler, J L
1996-01-01
A significant proportion of coding sequences or open reading frames discovered in the course of sequencing projects do not show any similarity with other sequences deposited with the protein databanks. In such cases the search for similarities must be performed with as many comparison algorithms as possible, so as to increase the chance of finding weak relationships. A specialised parallel hardware (SAMBA) implementing the Smith & Waterman algorithm has been developed at the 'Institut de Recherche en Informatique et Systèmes Aléatoìres' (IRISA). It makes it possible to scan protein databanks at a speed comparable with that of BLAST or FASTA. We report here a study performed with SAMBA on 814 orphan sequences from S cerevisiae and compare the results with those from BLAST and FASTA. PMID:8905149
NASA Astrophysics Data System (ADS)
Astone, Pia; Weinstein, Alan; Agathos, Michalis; Bejger, Micha?; Christensen, Nelson; Dent, Thomas; Graff, Philip; Klimenko, Sergey; Mazzolo, Giulio; Nishizawa, Atsushi; Robinet, Florent; Schmidt, Patricia; Smith, Rory; Veitch, John; Wade, Madeline; Aoudia, Sofiane; Bose, Sukanta; Calderon Bustillo, Juan; Canizares, Priscilla; Capano, Colin; Clark, James; Colla, Alberto; Cuoco, Elena; Da Silva Costa, Carlos; Dal Canton, Tito; Evangelista, Edgar; Goetz, Evan; Gupta, Anuradha; Hannam, Mark; Keitel, David; Lackey, Benjamin; Logue, Joshua; Mohapatra, Satyanarayan; Piergiovanni, Francesco; Privitera, Stephen; Prix, Reinhard; Pürrer, Michael; Re, Virginia; Serafinelli, Roberto; Wade, Leslie; Wen, Linqing; Wette, Karl; Whelan, John; Palomba, C.; Prodi, G.
2015-02-01
The Amaldi 10 Parallel Session C2 on gravitational wave (GW) search results, data analysis and parameter estimation included three lively sessions of lectures by 13 presenters, and 34 posters. The talks and posters covered a huge range of material, including results and analysis techniques for ground-based GW detectors, targeting anticipated signals from different astrophysical sources: compact binary inspiral, merger and ringdown; GW bursts from intermediate mass binary black hole mergers, cosmic string cusps, core-collapse supernovae, and other unmodeled sources; continuous waves from spinning neutron stars; and a stochastic GW background. There was considerable emphasis on Bayesian techniques for estimating the parameters of coalescing compact binary systems from the gravitational waveforms extracted from the data from the advanced detector network. This included methods to distinguish deviations of the signals from what is expected in the context of General Relativity.
An Automated Directed Spectral Search Methodology for Small Target Detection
NASA Astrophysics Data System (ADS)
Grossman, Stanley I.
Much of the current efforts in remote sensing tackle macro-level problems such as determining the extent of wheat in a field, the general health of vegetation or the extent of mineral deposits in an area. However, for many of the remaining remote sensing challenges being studied currently, such as border protection, drug smuggling, treaty verification, and the war on terror, most targets are very small in nature - a vehicle or even a person. While in typical macro-level problems the objective vegetation is in the scene, for small target detection problems it is not usually known if the desired small target even exists in the scene, never mind finding it in abundance. The ability to find specific small targets, such as vehicles, typifies this problem. Complicating the analyst's life, the growing number of available sensors is generating mountains of imagery outstripping the analysts' ability to visually peruse them. This work presents the important factors influencing spectral exploitation using multispectral data and suggests a different approach to small target detection. The methodology of directed search is presented, including the use of scene-modeled spectral libraries, various search algorithms, and traditional statistical and ROC curve analysis. The work suggests a new metric to calibrate analysis labeled the analytic sweet spot as well as an estimation method for identifying the sweet spot threshold for an image. It also suggests a new visualization aid for highlighting the target in its entirety called nearest neighbor inflation (NNI). It brings these all together to propose that these additions to the target detection arena allow for the construction of a fully automated target detection scheme. This dissertation next details experiments to support the hypothesis that the optimum detection threshold is the analytic sweet spot and that the estimation method adequately predicts it. Experimental results and analysis are presented for the proposed directed search techniques of spectral image based small target detection. It offers evidence of the functionality of the NNI visualization and also provides evidence that the increased spectral dimensionality of the 8-band Worldview-2 datasets provides noteworthy improvement in results over traditional 4-band multispectral datasets. The final experiment presents the results from a prototype fully automated target detection scheme in support of the overarching premise. This work establishes the analytic sweet spot as the optimum threshold defined as the point where error detection rate curves -- false detections vs. missing detections -- cross. At this point the errors are minimized while the detection rate is maximized. It then demonstrates that taking the first moment statistic of the histogram of calculated target detection values from a detection search with test threshold set arbitrarily high will estimate the analytic sweet spot for that image. It also demonstrates that directed search techniques -- when utilized with appropriate scene-specific modeled signatures and atmospheric compensations -- perform at least as well as in-scene search techniques 88% of the time and grossly under-performing only 11% of the time; the in-scene only performs as well or better 50% of the time. It further demonstrates the clear advantage increased multispectral dimensionality brings to detection searches improving performance in 50% of the cases while performing at least as well 72% of the time. Lastly, it presents evidence that a fully automated prototype performs as anticipated laying the groundwork for further research into fully automated processes for small target detection.
Torczon, Virginia
that the Nelder-Mead algorithm may be unreliable even in fairly simple situations. In contrast, many that the Nelder-Mead simplex algorithm lacks. We will close with some practical sug- gestions for using pattern
Convergence of Mesh Adaptive Direct Search to Second-Order Stationary Points
Mark A. Abramson; Charles Audet
2006-01-01
A previous analysis of second-order behavior of generalized pattern search algorithms for unconstrained and linearly constrained minimization is extended to the more general class of mesh adaptive direct search (MADS) algorithms for general con- strained optimization. Because of the ability of MADS to generate an asymptotically dense set of search directions, we are able to establish reasonable conditions under which
Evolution Strategies for Direct Policy Search Verena Heidrich-Meisner and Christian Igel
Igel, Christian
method and stochastic search on the double cart-pole balancing task us- ing linear policies. The CMA methods searching directly in policy space such as policy gradient methods (PGMs), which are wellEvolution Strategies for Direct Policy Search Verena Heidrich-Meisner and Christian Igel Institut f
Parallel direct laser writing of micro-optical and photonic structures using spatial light modulator
NASA Astrophysics Data System (ADS)
Yang, Liang; El-Tamer, Ayman; Hinze, Ulf; Li, Jiawen; Hu, Yanlei; Huang, Wenhao; Chu, Jiaru; Chichkov, Boris N.
2015-07-01
Two-photon polymerization (2PP) is a powerful tool for direct laser writing of micro-optical and photonic structures due to its flexibility in 3D structuring and sub-micrometer resolution. However, it can be time consuming to fabricate arrays of micro-optical devices and complex photonic structures. In this study, we propose to use predefined patterns (PPs) for parallel 2PP processing. A PP contains a multiple focal spot pattern optimized for the fabrication of certain microstructures. PP can be created by holographic laser beam modulation with a spatial light modulator (SLM). The quantity and position of the multiple foci can be flexibly and precisely controlled by predesigned computer generated holograms (CGHs). With these specially designed PPs, parallel fabrication of arbitrary distributed microlens arrays and 3D photonic structures is demonstrated. This method significantly improves throughput and flexibility of the 2PP technique and can be used for mass production of functional devices in micro-optics and photonics.
Massively Parallel Phase-Field Simulations for Ternary Eutectic Directional Solidification
Bauer, Martin; Steinmetz, Philipp; Jainta, Marcus; Berghoff, Marco; Schornbaum, Florian; Godenschwager, Christian; Köstler, Harald; Nestler, Britta; Rüde, Ulrich
2015-01-01
Microstructures forming during ternary eutectic directional solidification processes have significant influence on the macroscopic mechanical properties of metal alloys. For a realistic simulation, we use the well established thermodynamically consistent phase-field method and improve it with a new grand potential formulation to couple the concentration evolution. This extension is very compute intensive due to a temperature dependent diffusive concentration. We significantly extend previous simulations that have used simpler phase-field models or were performed on smaller domain sizes. The new method has been implemented within the massively parallel HPC framework waLBerla that is designed to exploit current supercomputers efficiently. We apply various optimization techniques, including buffering techniques, explicit SIMD kernel vectorization, and communication hiding. Simulations utilizing up to 262,144 cores have been run on three different supercomputing architectures and weak scalability results are show...
NASA Technical Reports Server (NTRS)
Zhang, Meng; Maxworthy, Tony
1999-01-01
It has long been recognized that flow in the melt can have a profound influence on the dynamics of a solidifying interface and hence the quality of the solid material. In particular, flow affects the heat and mass transfer, and causes spatial and temporal variations in the flow and melt composition. This results in a crystal with nonuniform physical properties. Flow can be generated by buoyancy, expansion or contraction upon phase change, and thermo-soluto capillary effects. In general, these flows can not be avoided and can have an adverse effect on the stability of the crystal structures. This motivates crystal growth experiments in a microgravity environment, where buoyancy-driven convection is significantly suppressed. However, transient accelerations (g-jitter) caused by the acceleration of the spacecraft can affect the melt, while convection generated from the effects other than buoyancy remain important. Rather than bemoan the presence of convection as a source of interfacial instability, Hurle in the 1960s suggested that flow in the melt, either forced or natural convection, might be used to stabilize the interface. Delves considered the imposition of both a parabolic velocity profile and a Blasius boundary layer flow over the interface. He concluded that fast stirring could stabilize the interface to perturbations whose wave vector is in the direction of the fluid velocity. Forth and Wheeler considered the effect of the asymptotic suction boundary layer profile. They showed that the effect of the shear flow was to generate travelling waves parallel to the flow with a speed proportional to the Reynolds number. There have been few quantitative, experimental works reporting on the coupling effect of fluid flow and morphological instabilities. Huang studied plane Couette flow over cells and dendrites. It was found that this flow could greatly enhance the planar stability and even induce the cell-planar transition. A rotating impeller was buried inside the sample cell, driven by an outside rotating magnet, in order to generate the flow. However, it appears that this was not a well-controlled flow and may also have been unsteady. In the present experimental study, we want to study how a forced parallel shear flow in a Hele-Shaw cell interacts with the directionally solidifying crystal interface. The comparison of experimental data show that the parallel shear flow in a Hele-Shaw cell has a strong stabilizing effect on the planar interface by damping the existing initial perturbations. The flow also shows a stabilizing effect on the cellular interface by slightly reducing the exponential growth rate of cells. The left-right symmetry of cells is broken by the flow with cells tilting toward the incoming flow direction. The tilting angle increases with the velocity ratio. The experimental results are explained through the parallel flow effect on lateral solute transport. The phenomenon of cells tilting against the flow is consistent with the numerical result of Dantzig and Chao.
Model-based halftoning using direct binary search
NASA Astrophysics Data System (ADS)
Analoui, Mostafa; Allebach, Jan P.
1992-08-01
In this work, we propose a new method to generate halftone images which are visually optimized for the display device. The algorithm searches for a binary array of pixel values that minimizes the difference between the perceived displayed continuous-tone image and the perceived displayed halftone image. The algorithm is based on the direct binary search (DBS) heuristic. Since the algorithm is iterative, it is computationally intensive. This limits the complexity of the visual model that can be used. It also impacts the choice of the metric used to measure distortion between two perceived images. In particular, we use a linear, shift- invariant model with a point spread function based on measurement of contrast sensitivity as a function of spatial frequency. The non-ideal spot shape rendered by the output devices can also have a major effect on the displayed halftone image. This source of non-ideality is explicitly accounted for in our model for the display device. By recursively computing the change in perceived mean-squared error due to a change in the value of a binary pixel, we achieve a substantial reduction in computational complexity. The effect of a trial change may be evaluated with only table lookups and a few additions.
Direct WIMP searches with XENON100 and XENON1T
NASA Astrophysics Data System (ADS)
Alfredo Davide, Ferella
2015-05-01
The XENON100 experiment is the second phase of the XENON direct Dark Matter search program. It consists of an ultra-low background double phase (liquid-gas) xenon filled time projection chamber with a total mass of 161 kg (62 in the target region and 99 in the active shield), installed at the Laboratori Nazionali del Gran Sasso (LNGS). Here the results from the 224.6 live days of data taken between March 2011 and April 2012 are reported. The experiment set one of the most stringent limits on the WIMP-nucleon spin-independent cross section to date (2 × 10-45 cm2 for a 55 Gev/c2 WIMP mass at 90 % confidence level) and the most stringent on the spin-dependent WIMP-neutron interaction (3.5 × 10-40 for a 45 GeV/c2 WIMP mass). With the same dataset, XENON100 excludes also solar axion coupling to electrons at gAe > 7.7 × 10-12 for a mass of mAxion <1 keV/c2 and galactic axion couplings by gAe > 1 × 10-12 at a mass range of mAxion = 5-10 keV/c2 (both 90 % C.L.). Moreover an absolute spectral comparison between simulated and measured nuclear recoil distributions of light and charge signals from a 241AmBe source demonstrates a high level of detector and systematics understanding. Finally, the third generation of the XENON experiments, XENON1T, is the first tonne scale direct WIMP search experiment currently under construction. The commissioning phase of XENON1T is expected to start in early 2015 followed, a few months after, by the first science run. The experiment will reach sensitivities on the WIMP-nucleon spin-independent cross section down to 2 ×10-47 cm2 after two years of data taking.
Direct numerical simulation of instabilities in parallel flow with spherical roughness elements
NASA Technical Reports Server (NTRS)
Deanna, R. G.
1992-01-01
Results from a direct numerical simulation of laminar flow over a flat surface with spherical roughness elements using a spectral-element method are given. The numerical simulation approximates roughness as a cellular pattern of identical spheres protruding from a smooth wall. Periodic boundary conditions on the domain's horizontal faces simulate an infinite array of roughness elements extending in the streamwise and spanwise directions, which implies the parallel-flow assumption, and results in a closed domain. A body force, designed to yield the horizontal Blasius velocity in the absence of roughness, sustains the flow. Instabilities above a critical Reynolds number reveal negligible oscillations in the recirculation regions behind each sphere and in the free stream, high-amplitude oscillations in the layer directly above the spheres, and a mean profile with an inflection point near the sphere's crest. The inflection point yields an unstable layer above the roughness (where U''(y) is less than 0) and a stable region within the roughness (where U''(y) is greater than 0). Evidently, the instability begins when the low-momentum or wake region behind an element, being the region most affected by disturbances (purely numerical in this case), goes unstable and moves. In compressible flow with periodic boundaries, this motion sends disturbances to all regions of the domain. In the unstable layer just above the inflection point, the disturbances grow while being carried downstream with a propagation speed equal to the local mean velocity; they do not grow amid the low energy region near the roughness patch. The most amplified disturbance eventually arrives at the next roughness element downstream, perturbing its wake and inducing a global response at a frequency governed by the streamwise spacing between spheres and the mean velocity of the most amplified layer.
Direct Spatial Search on Pictorial Databases Using Packed R-Trees
Nick Roussopoulos; Daniel Leifker
1985-01-01
Pictorial databases require efficient and direct spatial search based on the analog form of spatial objects and relationships instead of search based on some cumbersome alphanumeric encodings of the pictures. R-trees (two- dimensional B-trees) are excellent devices for indexing spatial objects and relationships found on pictures. Their most important feature is that they provide high level object oriented search rather
NASA Astrophysics Data System (ADS)
Campo, Lorenzo; Castelli, Fabio; Caparrini, Francesca
2010-05-01
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.
NASA Technical Reports Server (NTRS)
Miller, R. H.; Gombosi, T. I.; Gary, S. P.; Winske, D.
1991-01-01
The direction of propagation of low frequency magnetic fluctuations generated by cometary ion pick-up is examined by means of 1D electromagnetic hybrid simulations. The newborn ions are injected at a constant rate, and the helicity and direction of propagation of magnetic fluctuations are explored for cometary ion injection angles of 0 and 90 deg relative to the solar wind magnetic field. The parameter eta represents the relative contribution of wave energy propagating in the direction away from the comet, parallel to the beam. For small (quasi-parallel) injection angles eta was found to be of order unity, while for larger (quasi-perpendicular) angles eta was found to be of order 0.5.
Scott, Michael L.
in Parallel Processing administered by the Institute for Advanced Com- puter Studies, University of MarylandThe Advantages of Multiple Parallelizations in Cornbinatorial Search* ^Computer Science Department, Oregon State University, Corvallis, Oregon 97331-3202; and ^.ComputerScience Department, University
Direct tabu search algorithm for the fiber Bragg grating distributed strain sensing
NASA Astrophysics Data System (ADS)
Karim, F.; Seddiki, O.
2010-09-01
A direct tabu search (DTS) algorithm used for determining the strain profile along a fiber Bragg grating (FBG) from its reflection spectrum has been demonstrated. By combining the transfer matrix method (TMM) for calculating the reflection spectrum of an FBG and the DTS method, we obtain a new method for the distributed sensing. Direct search based strategies are used to direct a tabu search. These strategies are based on a new pattern search procedure called an adaptive pattern search (APS). In addition, the well-known Nelder-Mead (NME) algorithm is used as a local search method in the final stage of the optimization process. The numerical simulations show good agreement between the original and the reconstructed strain profiles.
Job Search as Goal-Directed Behavior: Objectives and Methods
ERIC Educational Resources Information Center
Van Hoye, Greet; Saks, Alan M.
2008-01-01
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…
Carena, Marcela; Hooper, Dan; /Fermilab; Vallinotto, Alberto; /Fermilab /Chicago U. /Paris, Inst. Astrophys.
2006-11-01
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.
Guido M. Kukuk; Dariusch R. Hadizadeh; Jürgen Gieseke; Marcus von Falkenhausen; Ingrid Böhm; Renate Semrau; Horst Urbach; Arne Koscielny; Frauke Verrel; Kai Wilhelm; Hans H. Schild; Winfried A. Willinek
2010-01-01
PurposeTo present the feasibility of highly undersampled contrast-enhanced MRA (CE-MRA) of the supraaortic arteries with a 16-channel neurovascular coil at 3.0 T using parallel imaging in two directions with parallel imaging factors (PIF) up to 16.
PeliGRIFF, a parallel DEM-DLM\\/FD direct numerical simulation tool for 3D particulate flows
Anthony Wachs
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
Junichiro Makino
2001-08-27
We present a novel, highly efficient algorithm to parallelize O(N^2) direct summation method for N-body problems with individual timesteps on distributed-memory parallel machines such as Beowulf clusters. Previously known algorithms, in which all processors have complete copies of the N-body system, has the serious problem that the communication-computation ratio increases as we increase the number of processors, since the communication cost is independent of the number of processors. In the new algorithm, p processors are organized as a $\\sqrt{p}\\times \\sqrt{p}$ two-dimensional array. Each processor has $N/\\sqrt{p}$ particles, but the data are distributed in such a way that complete system is presented if we look at any row or column consisting of $\\sqrt{p}$ processors. In this algorithm, the communication cost scales as $N /\\sqrt{p}$, while the calculation cost scales as $N^2/p$. Thus, we can use a much larger number of processors without losing efficiency compared to what was practical with previously known algorithms.
Reward Weighted Regression with Sample Reuse for Direct Policy Search in Reinforcement Learning 1
Introduction Policy search is an important tool for solving real-world Markov decision problems online. However of collecting rollout data is often prohibitively expensive and too time-consuming for real-world problems whereReward Weighted Regression with Sample Reuse for Direct Policy Search in Reinforcement Learning 1
Sarah A. Malik; Christopher McCabe; Henrique Araujo; Alexander Belyaev; Celine Boehm; Jim Brooke; Oliver Buchmueller; Gavin Davies; Albert De Roeck; Kees de Vries; Matthew J. Dolan; John Ellis; Malcolm Fairbairn; Henning Flaecher; Loukas Gouskos; Valentin V. Khoze; Greg Landsberg; Dave Newbold; Michele Papucci; Timothy Sumner; Marc Thomas; Steven Worm
2014-09-23
In this White Paper we present and discuss a concrete proposal for the consistent interpretation of Dark Matter searches at colliders and in direct detection experiments. Based on a specific implementation of simplified models of vector and axial-vector mediator exchanges, this proposal demonstrates how the two search strategies can be compared on an equal footing.
A NEW SEARCH FOR DIRECT CP VIOLATION IN HYPERON DECAYS K. S. NELSON
Fermilab Experiment E871
A NEW SEARCH FOR DIRECT CP VIOLATION IN HYPERON DECAYS K. S. NELSON Dept. of Physics, University of Virginia, 205 McCormick Rd., Charlottesville, Virginia, USA Representing the HyperCP Collaboration The HyperCP experiment 1 (Fermilab E871) is performing a search for CP violation in \\Xi and \\Lambda hyperon
Search for direct CP violation in singly Cabibbo-suppressed D±?K+K-?± decays
Cowan, Ray Franklin
We report on a search for direct CP violation in the singly Cabibbo-suppressed decay D[superscript +]-->K[superscript +]K[superscript -]?[superscript +] using a data sample of 476??fb[subscript -1] of e[superscript ...
A Comparison of Two Self-Directed Career Guidance Instruments: Occu-Sort and Self-Directed Search.
ERIC Educational Resources Information Center
Jones, Lawrence K.
1983-01-01
Evaluated the Occu-Sort, and the Self-Directed Search, focusing on six areas of interest to school counselors, e.g., proportion of nontraditional occupations suggested and later considered, number suggested and later considered, understanding and recall of the letter codes, and reliability of the self-scored occupational code for the O-S. (PAS)
HYPER-HEURISTICS: AN EMERGING DIRECTION IN MODERN SEARCH TECHNOLOGY
Edmund Burke; Emma Hart; G raham Kendall; Peter Ross; Sonia Schulenburg
2003-01-01
This chapter introduces and overviews an emerging methodology in search and optimisation. One of the key aims of these new approaches, which have been termed hyper-heuristics, is to raise the level of generality at which optimisation systems can operate. An objective is that hyper-heuristics will lead to more general systems that are able to handle a wide range of problem
Solar neutrions as background in direct dark matter searches
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
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.
Some Comments on Possible Preferred Directions for the SETI Search
Nussinov, Shmuel
2009-01-01
The search for extraterrestrial intelligence by looking for signals from advanced technological civilizations has been ongoing for some decades. We suggest that it could possibly be made more efficient by focusing on stars from which the solar system can be observed via mini-eclipsings of the Sun by transiting planets.
Speeding Up Learning in Real-Time Search through Parallel Computing
Vinicius Marques; Luiz Chaimowicz; Renato Ferreira
2011-01-01
Real-time search algorithms solve the problem of path planning, regardless the size and complexity of the maps, and the massive presence of entities in the same environment. In such methods, the learning step aims to avoid local minima and improve the results for future searches, ensuring the convergence to the optimal path when the same planning task is solved repeatedly.
A Ka-band direct oscillation HBT VCO MMIC with a parallel negative resistor circuit
Kenichiro Choumei; Takayuki Matsuzuka; Satoshi Suzuki; Satoshi Hamano; Kenji Kawakami; Nobuyuki Ogawa; Makio Komaru; Yoshio Matsuda
2005-01-01
This paper describes a low phase noise Ka-band VCO MMIC employing InGaP\\/GaAs HBT processes. The VCO has the following two features: a novel circuit comprising negative resistors arranged in parallel that achieves a steep phase slope, and a tuning circuit with two resonators that offers a wide tuning range and steep phase slope. Measurement results of the developed VCO show
Parallel Direct Solution of Linear Equations on FPGA-Based Machines
Xiaofang Wang; Sotirios G. Ziavras
2003-01-01
The efficient solution of large systems of linear equations represented by sparse matrices appears in many tasks. LU factorization followed by backward and forward substitutions is widely used for this purpose. Parallel implementations of this computation-intensive process are limited primarily to supercomputer s. New generations of Field -Programmable Gate Array (FPGA) technologies enable the implementation of System -On-a- Programmable-Chip (SOPC)
NASA Astrophysics Data System (ADS)
Theos, F. V.; Lagaris, I. E.; Papageorgiou, D. G.
2004-05-01
We present two sequential and one parallel global optimization codes, that belong to the stochastic class, and an interface routine that enables the use of the Merlin/MCL environment as a non-interactive local optimizer. This interface proved extremely important, since it provides flexibility, effectiveness and robustness to the local search task that is in turn employed by the global procedures. We demonstrate the use of the parallel code to a molecular conformation problem. Program summaryTitle of program: PANMIN Catalogue identifier: ADSU Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSU Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer for which the program is designed and others on which it has been tested: PANMIN is designed for UNIX machines. The parallel code runs on either shared memory architectures or on a distributed system. The code has been tested on a SUN Microsystems ENTERPRISE 450 with four CPUs, and on a 48-node cluster under Linux, with both the GNU g77 and the Portland group compilers. The parallel implementation is based on MPI and has been tested with LAM MPI and MPICH Installation: University of Ioannina, Greece Programming language used: Fortran-77 Memory required to execute with typical data: Approximately O( n2) words, where n is the number of variables No. of bits in a word: 64 No. of processors used: 1 or many Has the code been vectorised or parallelized?: Parallelized using MPI No. of bytes in distributed program, including test data, etc.: 147163 No. of lines in distributed program, including the test data, etc.: 14366 Distribution format: gzipped tar file Nature of physical problem: A multitude of problems in science and engineering are often reduced to minimizing a function of many variables. There are instances that a local optimum does not correspond to the desired physical solution and hence the search for a better solution is required. Local optimization techniques can be trapped in any local minimum. Global Optimization is then the appropriate tool. For example, solving a non-linear system of equations via optimization, one may encounter many local minima that do not correspond to solutions, i.e. they are far from zero Method of solution: PANMIN is a suite of programs for Global Optimization that take advantage of the Merlin/MCL optimization environment [1,2]. We offer implementations of two algorithms that belong to the stochastic class and use local searches either as intermediate steps or as solution refinement Restrictions on the complexity of the problem: The only restriction is set by the available memory of the hardware configuration. The software can handle bound constrained problems. The Merlin Optimization environment must be installed. Availability of an MPI installation is necessary for executing the parallel code Typical running time: Depending on the objective function References: [1] D.G. Papageorgiou, I.N. Demetropoulos, I.E. Lagaris, Merlin-3.0. A multidimensional optimization environment, Comput. Phys. Commun. 109 (1998) 227-249. [2] D.G. Papageorgiou, I.N. Demetropoulos, I.E. Lagaris, The Merlin Control Language for strategic optimization, Comput. Phys. Commun. 109 (1998) 250-275.
Direct observation of TALE protein dynamics reveals a two-state search mechanism
Cuculis, Luke; Abil, Zhanar; Zhao, Huimin; Schroeder, Charles M.
2015-01-01
Transcription activator-like effector (TALE) proteins are a class of programmable DNA-binding proteins for which the fundamental mechanisms governing the search process are not fully understood. Here we use single-molecule techniques to directly observe TALE search dynamics along DNA templates. We find that TALE proteins are capable of rapid diffusion along DNA using a combination of sliding and hopping behaviour, which suggests that the TALE search process is governed in part by facilitated diffusion. We also observe that TALE proteins exhibit two distinct modes of action during the search process—a search state and a recognition state—facilitated by different subdomains in monomeric TALE proteins. Using TALE truncation mutants, we further demonstrate that the N-terminal region of TALEs is required for the initial non-specific binding and subsequent rapid search along DNA, whereas the central repeat domain is required for transitioning into the site-specific recognition state. PMID:26027871
Serial Attention Mechanisms in Visual Search: A Direct Behavioral Demonstration
Emanuela Bricolo; Tiziana Gianesini; Alessandra Fanini; Claus Bundesen; Leonardo Chelazzi
2002-01-01
In visual search, inefficient performance of human observers is typically characterized by a steady increase in reaction time with the number of array elementsthe so-called set-size effect. In general, set-size effects are taken to indicate that processing of the array elements depends on limited-capacity resources, that is, it involves attention. Contrasting theories have been proposed to account for this attentional
Neutrinoless double beta decay and direct searches for neutrino mass
Craig Aalseth; Henning Back; Loretta Dauwe; David Dean; Guido Drexlin; Yuri Efremenko; Hiro Ejiri; Steven Elliott; Jon Engel; Brian Fujikawa; Reyco Henning; G. W. Hoffmann; Karol Lang; Kevin Lesko; Tadafumi Kishimoto; Harry Miley; Rick Norman; Silvia Pascoli; Serguey Petcov; Andreas Piepke; Werner Rodejohann; David Saltzberg; Sean Sutton; Petr Vogel; Ray Warner; John Wilkerson; Lincoln Wolfenstein
2004-12-21
Study of the neutrinoless double beta decay and searches for the manifestation of the neutrino mass in ordinary beta decay are the main sources of information about the absolute neutrino mass scale, and the only practical source of information about the charge conjugation properties of the neutrinos. Thus, these studies have a unique role in the plans for better understanding of the whole fast expanding field of neutrino physics.
Pyramidal Search of Maximum Coherence Direction for Biomedical Image Interpolation
North Carolina at Chapel Hill, University of
in this paper. It is an extension of the work on Directional Coherence Interpolation (DCI) [15] Â a novel gray single resolution DCI. 1. Introduction Multiresolution processing is a powerful idea [10, 1], whose birth computation cost, a new method called Directional Coherence Interpolation (DCI) was presented in [15
Shermeen Nizami; James. R. Green; J. Mikael Eklund; Carolyn McGregor
2010-01-01
Heart rate variability (HRV) is an established indicator of cardiac health. Recent developments have shown the potential of nonlinear metrics for pattern classification of various heart conditions. Evidence indicates that the combination of multiple linear and nonlinear features leads to increased classification accuracy. In our paper, we demonstrate HRV classification using two dynamic nonlinear techniques called Parallel Cascade Identification (PCI)
Parallel and Serial Neural Mechanisms for Visual Search in Macaque Area V4
Narcisse P. Bichot; Andrew F. Rossi; Robert Desimone
2005-01-01
To find a target object in a crowded scene, a face in a crowd for example, the visual system might turn the neural representation of each object on and off in a serial fashion, testing each representation against a template of the target item. Alternatively, it might allow the processing of all objects in parallel but bias activity in favor
Earthquake Location, Direct, Global-Search Methods E 2449 Earthquake Location,
Earthquake Location, Direct, Global-Search Methods E 2449 Earthquake Location, Direct, Global Kingdom Article Outline Glossary Definition of the Subject Introduction The Earthquake Location Problem or temporal av- erage of some characteristic of an earthquake, such as surface shaking intensity or moment
CDF/PHYS/BOTTOM/CDFR/6989 Measurement of Partial Widths and Search for Direct CP Violation
Fermilab
CDF/PHYS/BOTTOM/CDFR/6989 Draft 2.0 Measurement of Partial Widths and Search for Direct CP present a measurement of relative partial widths and decay rate CP asym- metries in K K + and #25; #25;- cant direct CP violation is observed and we measure: (D 0 ! K K + )=(D 0 ! K #25; + ) = 0:0996 #6; 0
NASA Astrophysics Data System (ADS)
Akazawa, Toshinobu; Sasaki, Seiryu; Jürgen Mattausch, Hans
2014-01-01
A scalable word-parallel associative memory for smallest Euclidean distance (ED) search is presented. Due to the applied concept of distance to clock-number mapping, the reported architecture is digital in nature and scalable to advanced technology. Furthermore, the reference data of feature vectors can be scaled in principle to any vector dimension and number. Handling of the numerical complexity of the ED without large consumption of Silicon area is achieved by an area-efficient circuit, which uses the same adder for absolute-difference calculation of vector components and subsequent square calculation by sequential addition of partial products. Additionally, a clock-number minimization algorithm is proposed to significantly reduce the clock-number needed for the search when the smallest ED is a large value. The concept of the proposed architecture has been experimentally verified by measurement results from real chips fabricated in a 180 nm CMOS technology, in which the architecture is configured for parallel smallest ED search among 32 reference vectors with each vector having 16 8-bit elements. For the application example of codebook-based data compression, the fabricated test chip achieved 1.19 µs average search time, 5.77 µs worst-case search time and low power consumption of 8.75 mW at the maximum clock frequency of 47 MHz and nominal power supply voltage Vdd = 1.8 V. At reduced power supply voltage Vdd = 1.2 V, a smaller power consumption of 2.80 mW at an also smaller maximum clock frequency of 24 MHz is measured. In comparison to previous analog-digital architecture, a reduction of the normalized power-delay product per matching operation by about a factor 1.6 at Vdd = 1.8 V (about factor 2.5 at Vdd = 1.2 V) is obtained with best-case data for the analog-digital architecture and average-case data for the proposed fully-digital architecture.
Current Results and Future Directions of the Pulsar Search Collaboratory
NASA Astrophysics Data System (ADS)
Heatherly, Sue Ann; Rosen, R.; McLaughlin, M.; Lorimer, D.
2011-01-01
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.
Martin E. Dyer; Sandeep Sen
2000-01-01
We describe a deterministic parallel algorithm for linear programming in fixed di- mension d that takes poly(log log n) time in the common concurrent read concurrent write (CRCW) PRAM model and does optimal O(n) work. In the exclusive read exclusive write (EREW) model, the algorithm runs in O(log n · log logd?1 n) time. Our algorithm is based on multidimensional
Shanechi, Maryam M; Wornell, Gregory W; Williams, Ziv M; Brown, Emery N
2013-01-01
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
Cache-Oblivious parallel SIMD Viterbi decoding for sequence search in HMMER
2014-01-01
Background HMMER is a commonly used bioinformatics tool based on Hidden Markov Models (HMMs) to analyze and process biological sequences. One of its main homology engines is based on the Viterbi decoding algorithm, which was already highly parallelized and optimized using Farrar’s striped processing pattern with Intel SSE2 instruction set extension. Results A new SIMD vectorization of the Viterbi decoding algorithm is proposed, based on an SSE2 inter-task parallelization approach similar to the DNA alignment algorithm proposed by Rognes. Besides this alternative vectorization scheme, the proposed implementation also introduces a new partitioning of the Markov model that allows a significantly more efficient exploitation of the cache locality. Such optimization, together with an improved loading of the emission scores, allows the achievement of a constant processing throughput, regardless of the innermost-cache size and of the dimension of the considered model. Conclusions The proposed optimized vectorization of the Viterbi decoding algorithm was extensively evaluated and compared with the HMMER3 decoder to process DNA and protein datasets, proving to be a rather competitive alternative implementation. Being always faster than the already highly optimized ViterbiFilter implementation of HMMER3, the proposed Cache-Oblivious Parallel SIMD Viterbi (COPS) implementation provides a constant throughput and offers a processing speedup as high as two times faster, depending on the model’s size. PMID:24884826
Parallel computation of GA search for the artery shape determinants with CFD
NASA Astrophysics Data System (ADS)
Himeno, M.; Noda, S.; Fukasaku, K.; Himeno, R.
2010-06-01
We studied which factors play important role to determine the shape of arteries at the carotid artery bifurcation by performing multi-objective optimization with computation fluid dynamics (CFD) and the genetic algorithm (GA). To perform it, the most difficult problem is how to reduce turn-around time of the GA optimization with 3D unsteady computation of blood flow. We devised two levels of parallel computation method with the following features: level 1: parallel CFD computation with appropriate number of cores; level 2: parallel jobs generated by "master", which finds quickly available job cue and dispatches jobs, to reduce turn-around time. As a result, the turn-around time of one GA trial, which would have taken 462 days with one core, was reduced to less than two days on RIKEN supercomputer system, RICC, with 8192 cores. We performed a multi-objective optimization to minimize the maximum mean WSS and to minimize the sum of circumference for four different shapes and obtained a set of trade-off solutions for each shape. In addition, we found that the carotid bulb has the feature of the minimum local mean WSS and minimum local radius. We confirmed that our method is effective for examining determinants of artery shapes.
NASA Astrophysics Data System (ADS)
Tamura, Hitoshi; Torii, Yasuhiro
2012-05-01
An optimization-coding algorithm is required to produce high-quality computer-generated holograms (CGHs). For such a purpose, we have developed the direct multilevel search (DMS) algorithm using the rigorous reconstructed-image representation for encoding Lohmann-type CGHs. However, it required much time owing to the one-by-one search process: the optimal amplitude and phase must be selected from many multilevel amplitudes and phases. To solve this problem, we have established the ±1-trial search method, which can greatly reduce the trial search number: searches are limited only to the minimum shifts in amplitude and phase instead of all the possible shifts. Moreover, the DMS algorithm that incorporates the oversampled encoding method has been verified to be effective for reducing the optical reconstructed-image error by preparing the CGHs using electron-beam lithography.
Oscillation modes of direct current microdischarges with parallel-plate geometry
Stefanovic, Ilija; Kuschel, Thomas; Winter, Joerg [Institut fuer Experimentalphysik II, Ruhr-Universitaet Bochum, 44781 Bochum (Germany); Skoro, Nikola; Maric, Dragana; Petrovic, Zoran Lj [Institute of Physics, University of Belgrade, POB 68, 11080 Belgrade (Serbia)
2011-10-15
Two different oscillation modes in microdischarge with parallel-plate geometry have been observed: relaxation oscillations with frequency range between 1.23 and 2.1 kHz and free-running oscillations with 7 kHz frequency. The oscillation modes are induced by increasing power supply voltage or discharge current. For a given power supply voltage, there is a spontaneous transition from one to other oscillation mode and vice versa. Before the transition from relaxation to free-running oscillations, the spontaneous increase of oscillation frequency of relaxation oscillations form 1.3 kHz to 2.1 kHz is measured. Fourier transform spectra of relaxation oscillations reveal chaotic behavior of microdischarges. Volt-ampere (V-A) characteristics associated with relaxation oscillations describes periodical transition between low current, diffuse discharge, and normal glow. However, free-running oscillations appear in subnormal glow only.
Lick Observatory Optical SETI: targeted search and new directions.
Stone, R P S; Wright, S A; Drake, F; Muñoz, M; Treffers, R; Werthimer, D
2005-10-01
Lick Observatory's Optical SETI (search for extraterrestrial intelligence) program has been in regular operation for 4.5 years. We have observed 4,605 stars of spectral types F-M within 200 light-years of Earth. Occasionally, we have appended objects of special interest, such as stars with known planetary systems. We have observed 14 candidate signals ("triple coincidences"), all but one of which are explained by transient local difficulties. Additional observations of the remaining candidate have failed to confirm arriving pulse events. We now plan to proceed in a more economical manner by operating in an unattended drift scan mode. Between operational and equipment modifications, efficiency will more than double. PMID:16225433
An efficient search direction for linear programming problems
Hsing Luh; Ray Tsaih
2002-01-01
In this paper, we present an auxiliary algorithm, in terms of the speed of obtaining the optimal solution, that is e!ective in helping the simplex method for commencing a better initial basic feasible solution. The idea of choosing a direction towards an optimal point presented in this paper is new and easily implemented. From our experiments, the algorithm will release
Managing Parallel Inquiries in Agents' Two-Sided Search David Sarne
Kraus, Sarit
of the general coalition formation model and its main incentive is similar to the one which drives coalitions.e., the agents forming it). Similarly, the two-sided nature of the search suggests that a partnership between for forming partnerships can be found in many traditional economical applications such as the marriage market
Parallel effects of memory set activation and search on timing and working memory capacity.
Schweickert, Richard; Fortin, Claudette; Xi, Zhuangzhuang; Viau-Quesnel, Charles
2014-01-01
Accurately estimating a time interval is required in everyday activities such as driving or cooking. Estimating time is relatively easy, provided a person attends to it. But a brief shift of attention to another task usually interferes with timing. Most processes carried out concurrently with timing interfere with it. Curiously, some do not. Literature on a few processes suggests a general proposition, the Timing and Complex-Span Hypothesis: A process interferes with concurrent timing if and only if process performance is related to complex span. Complex-span is the number of items correctly recalled in order, when each item presented for study is followed by a brief activity. Literature on task switching, visual search, memory search, word generation and mental time travel supports the hypothesis. Previous work found that another process, activation of a memory set in long term memory, is not related to complex-span. If the Timing and Complex-Span Hypothesis is true, activation should not interfere with concurrent timing in dual-task conditions. We tested such activation in single-task memory search task conditions and in dual-task conditions where memory search was executed with concurrent timing. In Experiment 1, activating a memory set increased reaction time, with no significant effect on time production. In Experiment 2, set size and memory set activation were manipulated. Activation and set size had a puzzling interaction for time productions, perhaps due to difficult conditions, leading us to use a related but easier task in Experiment 3. In Experiment 3 increasing set size lengthened time production, but memory activation had no significant effect. Results here and in previous literature on the whole support the Timing and Complex-Span Hypotheses. Results also support a sequential organization of activation and search of memory. This organization predicts activation and set size have additive effects on reaction time and multiplicative effects on percent correct, which was found. PMID:25120502
Microwave Experiments Simulating Quantum Search and Directed Transport in Artificial Graphene
Julian Böhm; Matthieu Bellec; Fabrice Mortessagne; Ulrich Kuhl; Sonja Barkhofen; Stefan Gehler; Hans-Jürgen Stöckmann; Iain Foulger; Sven Gnutzmann; Gregor Tanner
2015-03-28
A series of quantum search algorithms have been proposed recently providing an algebraic speedup compared to classical search algorithms from $N$ to $\\sqrt{N}$, where $N$ is the number of items in the search space. In particular, devising searches on regular lattices has become popular in extending Grover's original algorithm to spatial searching. Working in a tight-binding setup, it could be demonstrated, theoretically, that a search is possible in the physically relevant dimensions 2 and 3 if the lattice spectrum possesses Dirac points. We present here a proof of principle experiment implementing wave search algorithms and directed wave transport in a graphene lattice arrangement. The idea is based on bringing localized search states into resonance with an extended lattice state in an energy region of low spectral density---namely, at or near the Dirac point. The experiment is implemented using classical waves in a microwave setup containing weakly coupled dielectric resonators placed in a honeycomb arrangement, i.e., artificial graphene. Furthermore, we investigate the scaling behavior experimentally using linear chains.
Parallelized direct search of a binary objective P. Grant and D.G. Walker
Walker, D. Greg
-linear speedup up to 16 processors for most functions. 1 Introduction Engineering analysis is often concerned with identifying conditions responsible for catastrophic failure. For example, consider the load required to buckle a column. Using simple materials relations and static analysis, an estimate can be obtained for a range
Grant, Russell P; Cameron, Cheryl; Mackenzie-McMurter, Shelley
2002-01-01
The development of turbulent flow chromatography (TFC) has enabled considerable growth in the utility of on-line direct-injection technologies. TFC has now become established in a large number of varied analytical environments, particularly drug discovery/pharmacokinetics, metabolite profiling, combinatorial library purification, pre-clinical and clinical GLP applications. The utility of turbulent flow technology for in-house pre-clinical and clinical quantitative applications has necessitated extensive valve-cleaning procedures, and consequently lengthy cycle-times, to effectively remove the system carry-over. In-house requirements for assay validation require carry-over less than 20% of the lowest level of quantification (LLOQ), corresponding to 0.02% carry-over for a linear calibration range incorporating 3 orders. A generic turbulent flow chromatography protocol has been developed for drug discovery that incorporates polymeric turbulent flow extraction (cyclone) with C18-based reverse-phase chromatography. Further, multiple wash steps are incorporated within the methodology to meet in-house requirements for carry-over. Selection of novel switching-valve materials based on polyarylethyl ketone (PAEK) and Hastelloy/Valcon E autosampler injection hardware has enabled us to significantly impact the cycle-time required to reduce carry-over. Consequently, optimal usage of switching valves has enabled parallel operation for a generic on-line direct-injection methodology to successfully reduce the total cycle-time. Overall reductions from 4 min per sample to 90 s per sample are shown with comparable data quality using a proprietary target molecule from 0.1-100 ng/mL. This paper describes the hardware configuration and methodologies utilized to perform generic serial and parallel on-line direct-injection using a Turboflow HTLC 2300 system. PMID:12207368
Direct search of dark matter in high-scale supersymmetry
NASA Astrophysics Data System (ADS)
Hisano, Junji; Ishiwata, Koji; Nagata, Natsumi
2013-02-01
We study direct detection of dark matter in a supersymmetric model where most supersymmetric particles have very high-scale masses beyond the weak scale. In the scenario, a Wino-like or a Higgsino-like neutralino is a good candidate for the dark matter in the Universe. The neutralino scatters off nuclei by a Higgs boson exchange diagram and also electroweak loop diagrams. It is found that the elastic-scattering cross section with nuclei is enhanced or suppressed due to constructive or deconstructive interference among the diagrams. Such a cross section is within the reach of future experiment in some parameter region.
Jie Jin; Chi-ying Tsui
2007-01-01
In this paper, a low-power Viterbi decoder design based on scarce state transition (SST) is presented. A low complexity algorithm based on a limited search algorithm, which reduces the average number of the add-compare-select computation of the Viterbi algorithm, is proposed and seamlessly integrated with the SST-based decoder. The new decoding scheme has low overhead and facilitates low-power implementation for
Parallelization of enumerating tree-like chemical compounds by breadth-first search order
2015-01-01
Enumeration of chemical compounds greatly assists designing and finding new drugs, and determining chemical structures from mass spectrometry. In our previous study, we developed efficient algorithms, BfsSimEnum and BfsMulEnum for enumerating tree-like chemical compounds without and with multiple bonds, respectively. For many instances, our previously proposed algorithms were able to enumerate chemical structures faster than other existing methods. Latest processors consist of multiple processing cores, and are able to execute many tasks at the same time. In this paper, we develop three parallelized algorithms BfsEnumP1-3 by modifying BfsSimEnum in simple manners to further reduce execution time. BfsSimEnum constructs a family tree in which each vertex denotes a molecular tree. BfsEnumP1-3 divide a set of vertices with some given depth of the family tree into several subsets, each of which is assigned to each processor. For evaluation, we perform experiments for several instances with varying the division depth and the number of processors, and show that BfsEnumP1-3 are useful to reduce the execution time for enumeration of tree-like chemical compounds. In addition, we show that BfsEnumP3 achieves more than 80% parallelization efficiency using up to 11 processors, and reduce the execution time using 12 processors to about 1/10 of that by BfsSimEnum. PMID:26044861
NASA Technical Reports Server (NTRS)
Ellison, Donald C.; Giacalone, J.; Burgess, D.; Schwartz, S. J.
1993-01-01
We have made a direct comparison between two different computer simulations of a plane, parallel, collisionless shock including particle acceleration to energies typical of those of diffuse ions observed at the earth bow shock. Despite the fact that the one-dimensional hybrid and Monte Carlo techniques employ entirely different algorithms, they give surprisingly close agreement in the overall shapes of the complete distribution functions for protons as well as heavier ions. Both methods show that energetic ions emerge smoothly from the background thermal plasma with approximately the same relative injection rate and that the fraction of the incoming plasma's energy flux that is converted into downstream enthalpy flux of the accelerated population (i.e., the acceleration efficiency) is similar in the two cases. The fraction of the downstream proton distribution made up of superthermal particles is quite large, with at least 10% of the energy flux going into protons with energies above 10 keV. In addition, an upstream precursor, produced by backstreaming energetic particles, is present in both shocks, although the Monte Carlo precursor is considerably longer than that produced in the hybrid shock. These results offer convincing evidence that, at least in these ways, the two simulations are consistent in their description of parallel shock structure and particle acceleration, and they lay the groundwork for development of shock models employing a combination of both methods.
Influence of massively parallel e-beam direct-write pixel size on electron proximity correction
NASA Astrophysics Data System (ADS)
Lin, S. J.; Chen, P. S.; Shin, J. J.; Wang, W. C.; Lin, Burn J.
2011-04-01
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.
Parallel-Beam Diffraction and Direct Imaging in an Aberration-Corrected STEM
NASA Astrophysics Data System (ADS)
Krivanek, Ondrej L.
Aberration-corrected scanning transmission electron microscopes (STEMs) are versatile instruments that can perform many types of investigations. The main use of such microscopes has so far been in direct imaging and analysis, but they are equally well suited to performing diffraction studies and combined diffraction+imaging experiments. The various optical modes needed for such operating modes are reviewed. They include producing electron beams with angular spreads as narrow as a few ?rad, and conical precession scans with scan angles >50 mrad.
NASA Technical Reports Server (NTRS)
Gutmann, R. J.; Borrego, J. M.
1978-01-01
Rectenna conversion efficiencies (RF to dc) approximating 85 percent were demonstrated on a small scale, clearly indicating the feasibility and potential of efficiency of microwave power to dc. The overall cost estimates of the solar power satellite indicate that the baseline rectenna subsystem will be between 25 to 40 percent of the system cost. The directional receiving elements and element extensions were studied, along with power combining evaluation and evaluation extensions.
Taming astrophysical bias in direct dark matter searches
Pato, Miguel [Physik-Department T30d, Technische Universität München, James-Franck-Straße, 85748 Garching (Germany); Strigari, Louis E. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Trotta, Roberto [Astrophysics Group and Imperial Centre for Inference and Cosmology, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Bertone, Gianfranco, E-mail: miguel.pato@tum.de, E-mail: strigari@stanford.edu, E-mail: r.trotta@imperial.ac.uk, E-mail: gf.bertone@gmail.com [GRAPPA Institute, University of Amsterdam, Science Park 904, 1090 GL Amsterdam (Netherlands)
2013-02-01
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.
Bayes and present dark matter direct search status
Chiara Arina
2011-10-03
Recently there has been a huge activity in the dark matter direct detection field, with the report of an excess from CoGeNT and CRESST along with the annual modulated signal of DAMA/Libra and the strong exclusion bound from XENON100. We analyse these results within the framework of Bayesian inference and evidence. Indeed Bayesian methods are well suited for marginalizing over experimental systematics and background. We present the results for spin-independent interaction on nucleus with particular attention to the low dark matter mass region and the compatibility between experiments. In the same vein we also investigate the impact of astrophysical uncertainties on the WIMP preferred parameter space within the class of isotropic dark matter velocity distributions.
WIMP Dark Matter Direct-Detection Searches in Noble Gases
Laura Baudis
2014-08-19
Cosmological observations and the dynamics of the Milky Way provide ample evidence for an invisible and dominant mass component. This so-called dark matter could be made of new, colour and charge neutral particles, which were non-relativistic when they decoupled from ordinary matter in the early universe. Such weakly interacting massive particles (WIMPs) 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. Among these, detectors based on liquefied noble gases have demonstrated tremendous discovery potential over the last decade. After briefly introducing the phenomenology of direct dark matter detection, I will review the main properties of liquefied argon and xenon as WIMP targets and discuss sources of background. I will then describe existing and planned argon and xenon detectors that employ the so-called single- and dual-phase detection techniques, addressing their complementarity and science reach.
NASA Astrophysics Data System (ADS)
Lu, Y. H.; Huang, M. D.; Park, S. Y.; Kim, P. J.; Lee, Y. P.; Rhee, J. Y.
2006-03-01
We calculated the Faraday rotation of one-dimensional (1-D) magnetic photonic crystals (MPCs), which are based on the dielectric Ti2O3 and Al2O3, and the magnetic Bi:YIG, by employing 4 x 4 transfer-matrix method for the general case that the linearly polarized incident beam is parallel to their periodic direction, as mostly studied for the 1-D MPCs. Furthermore, even for a special case of normal incidence, the calculation of Faraday rotation was also carried out for such discontinuous thin films with a 1-D array structure and the existence of rotation was proved, which had been scarcely studied yet. The magneto-optical Faraday effects obtained for these two cases are compared and discussed in detail.
Massively Parallel Computing and the Search for Jets and Black Holes at the LHC
Halyo, V; Lujan, P
2013-01-01
Massively parallel computing at the LHC could be the next leap necessary to reach an era of new discoveries at the LHC after the Higgs-like discovery. Scientific computing is a critical component of the LHC experiment, including operation, trigger, LHC computing GRID, simulation, and analysis. One way to improve the physics reach of the LHC is to take advantage of the flexibility of the trigger system by integrating Graphics Processing Unit (GPU) or Many Integrated Core (MIC) processors into its server farm. This cutting edge technology provides not only the means to accelerate existing algorithms, but also the opportunity to develop new algorithms that select events that could have previously evaded detection. In this article we describe new algorithms to select prompt or non-prompt jet and black hole--like objects in the silicon tracker
WARREN L. DELANO; AXEL T. BRONGER
1995-01-01
Most rotation functions try to achieve maximal correla- tion between two Patterson functions by systematically rotating one and computing the overlap with the other. In contrast, the direct rotation function rotates a search model relative to the crystal unit cell and evaluates the linear correlation coefficient (Patterson correlation, PC) between squared normalized structure-factor amplitudes of the observed and calculated diffraction
Effects of the Self-Directed Search on High School Students
ERIC Educational Resources Information Center
Zener, Thelma Baldwin; Schnuelle, Leslie
1976-01-01
This study compares effects on high school students (N=959) of the Self Directed Search (SDS), the Vocational Preference Inventory (VPI), and no treatment. Students taking the SDS or the VPI evaluated the instruments, felt more satisfied with current occupational choices, and considered more occupational alternatives. Differences between the…
Geometric optimization of yield-line patterns using a direct search method
A. C. A. Ramsay; D. Johnson
1997-01-01
A class of problems in the geometric optimization of yield-line patterns, for which the currently advocatedconjugate gradient andsequential linear programming geometric optimization algorithms fail is investigated. TheHooke-Jeeves direct search method is implemented and is demonstrated to solve such problems robustly.
[Promising directions of search for antihypoxants and targets of their action].
Novikov, V E; Levchenkova, O S
2013-01-01
The modem notions about mechanisms of the organism adaptation to hypoxia are reviewed. Promising new directions in the search for effective medicinal agents with antihypoxant action are proposed. Probable targets for antihypoxant action, including mitochondrial ATP-dependent potassium channel (mito-KATP), mitochondrial megapore (mPTP), and hypoxia-inducible factor-1alfa (HIF-1alpha) are discussed. PMID:23901468
PHYSICAL REVIEW B 90, 115209 (2014) Computational search for direct band gap silicon crystals
Lee, Jooyoung
2014-01-01
PHYSICAL REVIEW B 90, 115209 (2014) Computational search for direct band gap silicon crystals In and dipole- allowed band gaps in the range of 0.8 to 1.5 eV for applications in thin-film solar cells [8
Directed search for gravitational waves from Scorpius X-1 with initial LIGO data
Aasi, J.
We present results of a search for continuously emitted gravitational radiation, directed at the brightest low-mass x-ray binary, Scorpius X-1. Our semicoherent analysis covers 10 days of LIGO S5 data ranging from 50–550 Hz, ...
A Maximum-Likelihood Strategy for Directing Attention during Visual Search
Duncan, James S.
- likelihood (ML) decision rule. The strategy has two important properties: First, it can be usedA Maximum-Likelihood Strategy for Directing Attention during Visual Search Hemant D. Tagare, Member the target is present in them. We call the strategy for choosing image regions an ªattention strategy
The Self-Directed Search: A Family of Self-Guided Career Interventions
Arnold R. Spokane; John L. Holland
1995-01-01
The Self-Directed Search (SDS; Holland, 1994) is a pair of booklets that simulate career counseling, accompanied by a set of derivative tools for use with the SDS. It is theoretically based, can be self- administered, self-scored, and self-interpreted and has a substantial base of studies examining its \\
Interpreting Self-Directed Search Profiles: Validity of the "Rule of Eight"
ERIC Educational Resources Information Center
Glavin, Kevin W.; Savickas, Mark L.
2011-01-01
Based on the standard error of measurement, Holland (1985) suggested the "rule of eight" for determining the meaningfulness of differences between two summary scores on the Self Directed Search. The present study empirically examined the rule's validity for practice. The participants were 2397 (1497 females and 900 males) undergraduate students…
Reference Directed Indexing: Redeeming Relevance for Subject Search in Citation Indexes
Bradshaw, Shannon
Reference Directed Indexing: Redeeming Relevance for Subject Search in Citation Indexes Shannon-bradshaw@uiowa.edu Abstract. Citation indexes are valuable tools for research, in part be- cause they provide a means new work within that space. Citation indexes such as CiteSeer [13] have proven extremely useful
Direct Answers for Search Queries in the Long Tail Michael S. Bernstein1
Direct Answers for Search Queries in the Long Tail Michael S. Bernstein1 , Jaime Teevan2 , Susan, and movies may return inline results called answers that can resolve a searcher's information need without any additional interaction. Despite the usefulness of answers, they are limited to popular needs
Using the Self-Directed Search: Career Explorer with High-Risk Middle School Students
ERIC Educational Resources Information Center
Osborn, Debra S.; Reardon, Robert C.
2006-01-01
The Self-Directed Search: Career Explorer was used with 98 (95% African American) high-risk middle school students as part of 14 structured career groups based on Cognitive Information Processing theory. Results and implications are presented on the outcomes of this program.
Twin Similarities in Holland Types as Shown by Scores on the Self-Directed Search
ERIC Educational Resources Information Center
Chauvin, Ida; McDaniel, Janelle R.; Miller, Mark J.; King, James M.; Eddlemon, Ondie L. M.
2012-01-01
This study examined the degree of similarity between scores on the Self-Directed Search from one set of identical twins. Predictably, a high congruence score was found. Results from a biographical sheet are discussed as well as implications of the results for career counselors.
Parallel mechanisms for direct and indirect membrane protein trafficking by synucleins
Oaks, Adam W; Sidhu, Anita
2013-01-01
More than 2 decades of work have yet to conclusively determine the physiological role of the synuclein proteins, even though these abundant brain constituents are participants in a broad array of cellular processes. Among proposed physiological roles is a functional interaction between the synuclein proteins and monoamine transporters contributing to transporter trafficking through direct protein–protein interactions. Recent work shows that an antagonistic effect of the synuclein proteins on the secretory functions of the endoplasmic reticulum and the Golgi apparatus appears to simultaneously influence trafficking of the dopamine transporter and other membrane proteins. Here, we highlight these new findings in view of the broader literature identifying the role of synucleins in protein trafficking and suggest emerging themes for ongoing and future work in the field of synuclein biology. PMID:24563712
A Search for Lyman Break Galaxies at z>8 in the NICMOS Parallel Imaging Survey
NASA Astrophysics Data System (ADS)
Henry, Alaina L.; Malkan, Matthew A.; Colbert, James W.; Siana, Brian; Teplitz, Harry I.; McCarthy, Patrick; Yan, Lin
2007-02-01
We have selected 14 J-dropout Lyman break galaxy (LBG) candidates with J110-H160>=2.5 from the NICMOS Parallel Imaging Survey. This survey consists of 135 arcmin2 of imaging in 228 independent sight lines, reaching average 5 ? sensitivities of J110=25.8 and H160=25.6 (AB). Distinguishing these candidates from dust-reddened star-forming galaxies at z~2-3 is difficult and will require longer wavelength observations. We consider the likelihood that any J-dropout LBGs exist in this survey and find that if L*z=9.5 is significantly brighter than L*z=6 (a factor of 4), then a few J-dropout LBGs are likely. A similar increase in luminosity has been suggested by Eyles et al. and Yan et al., but the magnitude of this increase is uncertain. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposals 9484, 9865, and 10226.
Search for direct CP-violation in singly-Cabibbo suppressed D+- --> K+ K- pi+- decays
BaBar Collaboration; J. P. Lees; V. Poireau; V. Tisserand; J. Garra Tico; E. Grauges; A. Palano; G. Eigen; B. Stugu; D. N. Brown; L. T. Kerth; Yu. G. Kolomensky; G. Lynch; H. Koch; T. Schroeder; D. J. Asgeirsson; C. Hearty; T. S. Mattison; J. A. McKenna; R. Y. So; A. Khan; V. E. Blinov; A. R. Buzykaev; V. P. Druzhinin; V. B. Golubev; E. A. Kravchenko; A. P. Onuchin; S. I. Serednyakov; Yu. I. Skovpen; E. P. Solodov; K. Yu. Todyshev; A. N. Yushkov; M. Bondioli; D. Kirkby; A. J. Lankford; M. Mandelkern; H. Atmacan; J. W. Gary; F. Liu; O. Long; G. M. Vitug; C. Campagnari; T. M. Hong; D. Kovalskyi; J. D. Richman; C. A. West; A. M. Eisner; J. Kroseberg; W. S. Lockman; A. J. Martinez; B. A. Schumm; A. Seiden; D. S. Chao; C. H. Cheng; B. Echenard; K. T. Flood; D. G. Hitlin; P. Ongmongkolkul; F. C. Porter; A. Y. Rakitin; R. Andreassen; Z. Huard; B. T. Meadows; M. D. Sokoloff; L. Sun; P. C. Bloom; W. T. Ford; A. Gaz; U. Nauenberg; J. G. Smith; S. R. Wagner; R. Ayad; W. H. Toki; B. Spaan; K. R. Schubert; R. Schwierz; D. Bernard; M. Verderi; P. J. Clark; S. Playfer; D. Bettoni; C. Bozzi; R. Calabrese; G. Cibinetto; E. Fioravanti; I. Garzia; E. Luppi; L. Piemontese; V. Santoro; R. Baldini-Ferroli; A. Calcaterra; R. de Sangro; G. Finocchiaro; P. Patteri; M. Piccolo; M. Rama; A. Zallo; R. Contri; E. Guido; M. Lo Vetere; M. R. Monge; S. Passaggio; C. Patrignani; E. Robutti; B. Bhuyan; V. Prasad; C. L. Lee; M. Morii; A. J. Edwards; A. Adametz; U. Uwer; H. M. Lacker; T. Lueck; P. D. Dauncey; U. Mallik; C. Chen; J. Cochran; W. T. Meyer; S. Prell; A. E. Rubin; A. V. Gritsan; Z. J. Guo; N. Arnaud; M. Davier; D. Derkach; G. Grosdidier; F. Le Diberder; A. M. Lutz; B. Malaescu; P. Roudeau; M. H. Schune; A. Stocchi; G. Wormser; D. J. Lange; D. M. Wright; C. A. Chavez; J. P. Coleman; J. R. Fry; E. Gabathuler; D. E. Hutchcroft; D. J. Payne; C. Touramanis; A. J. Bevan; F. Di Lodovico; R. Sacco; M. Sigamani; G. Cowan; D. N. Brown; C. L. Davis; A. G. Denig; M. Fritsch; W. Gradl; K. Griessinger; A. Hafner; E. Prencipe; R. J. Barlow; G. Jackson; G. D. Lafferty; E. Behn; R. Cenci; B. Hamilton; A. Jawahery; D. A. Roberts; C. Dallapiccola; R. Cowan; D. Dujmic; G. Sciolla; R. Cheaib; D. Lindemann; P. M. Patel; S. H. Robertson; P. Biassoni; N. Neri; F. Palombo; S. Stracka; L. Cremaldi; R. Godang; R. Kroeger; P. Sonnek; D. J. Summers; X. Nguyen; M. Simard; P. Taras; G. De Nardo; D. Monorchio; G. Onorato; C. Sciacca; M. Martinelli; G. Raven; C. P. Jessop; J. M. LoSecco; W. F. Wang; K. Honscheid; R. Kass; J. Brau; R. Frey; N. B. Sinev; D. Strom; E. Torrence; E. Feltresi; N. Gagliardi; M. Margoni; M. Morandin; M. Posocco; M. Rotondo; G. Simi; F. Simonetto; R. Stroili; S. Akar; E. Ben-Haim; M. Bomben; G. R. Bonneaud; H. Briand; G. Calderini; J. Chauveau; O. Hamon; Ph. Leruste; G. Marchiori; J. Ocariz; S. Sitt; M. Biasini; E. Manoni; S. Pacetti; A. Rossi; C. Angelini; G. Batignani; S. Bettarini; M. Carpinelli; G. Casarosa; A. Cervelli; F. Forti; M. A. Giorgi; A. Lusiani; B. Oberhof; E. Paoloni; A. Perez; G. Rizzo; J. J. Walsh; D. Lopes Pegna; J. Olsen; A. J. S. Smith; A. V. Telnov; F. Anulli; R. Faccini; F. Ferrarotto; F. Ferroni; M. Gaspero; L. Li Gioi; M. A. Mazzoni; G. Piredda; C. Bunger; O. Grunberg; T. Hartmann; T. Leddig; C. Voss; R. Waldi; T. Adye; E. O. Olaiya; F. F. Wilson; S. Emery; G. Hamel de Monchenault; G. Vasseur; Ch. Yeche; D. Aston; D. J. Bard; R. Bartoldus; J. F. Benitez; C. Cartaro; M. R. Convery; J. Dorfan; G. P. Dubois-Felsmann; W. Dunwoodie; M. Ebert; R. C. Field; M. Franco Sevilla; B. G. Fulsom; A. M. Gabareen; M. T. Graham; P. Grenier; C. Hast; W. R. Innes; M. H. Kelsey; P. Kim; M. L. Kocian; D. W. G. S. Leith; P. Lewis; B. Lindquist; S. Luitz; V. Luth; H. L. Lynch; D. B. MacFarlane; D. R. Muller; H. Neal; S. Nelson; M. Perl; T. Pulliam; B. N. Ratcliff; A. Roodman; A. A. Salnikov; R. H. Schindler; A. Snyder; D. Su; M. K. Sullivan; J. Va'vra; A. P. Wagner; W. J. Wisniewski; M. Wittgen; D. H. Wright; H. W. Wulsin; C. C. Young; V. Ziegler; W. Park; M. V. Purohit; R. M. White; J. R. Wilson; A. Randle-Conde; S. J. Sekula; M. Bellis; P. R. Burchat; T. S. Miyashita; E. M. T. Puccio; M. S. Alam; J. A. Ernst; R. Gorodeisky; N. Guttman; D. R. Peimer; A. Soffer; P. Lund; S. M. Spanier; J. L. Ritchie; A. M. Ruland; R. F. Schwitters; B. C. Wray; J. M. Izen; X. C. Lou; F. Bianchi; D. Gamba; S. Zambito; L. Lanceri; L. Vitale; F. Martinez-Vidal; A. Oyanguren; P. Villanueva-Perez; H. Ahmed; J. Albert; Sw. Banerjee; F. U. Bernlochner; H. H. F. Choi; G. J. King; R. Kowalewski; M. J. Lewczuk; I. M. Nugent; J. M. Roney; R. J. Sobie; N. Tasneem; T. J. Gershon; P. F. Harrison; T. E. Latham; H. R. Band; S. Dasu; Y. Pan; R. Prepost; S. L. Wu
2013-02-21
We report on a search for direct CP asymmetry in the singly Cabibbo-suppressed decay D+- --> K+ K- pi+- using a data sample of 476 fb-1 accumulated with the BaBar detector running at and just below the Y(4S) resonance. The CP-violating decay rate asymmetry A_CP is determined to be (0.35 +- 0.30 +- 0.15)%. Model-dependent and model-independent Dalitz plot analysis techniques are used to search for CP-violating asymmetries in the various intermediate states.
NASA Astrophysics Data System (ADS)
Ovaysi, S.; Piri, M.
2009-12-01
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.
Direct search coding algorithm with reduction in computing time by simultaneous selection rule
NASA Astrophysics Data System (ADS)
Tamura, Hitoshi
2014-05-01
An optimized encoding algorithm is required to produce high-quality computer-generated holograms (CGHs). For such a purpose, I have proposed that the use of the direct search algorithm (DSA) is effective for encoding the amplitude and phase in the Lohmann-type CGH. However, it takes much computation time to obtain an optimum solution by the DSA. To solve this problem, I have newly found that the simultaneous direct search algorithm (SDSA) is greatly effective for shortening the computation time for encoding the Lohmann-type CGH. As a result, the evaluation value of the reconstructed image for the SDSA is the same as that of 0.992 for the DSA. The computation time for the SDSA is drastically shortened from 3575 to 55 s for the DSA.
Influence of data volume and EPC on process window in massively parallel e-beam direct write
NASA Astrophysics Data System (ADS)
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
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.
A detection system to measure muon-induced neutrons for direct dark matter searches
V. Yu. Kozlov; E. Armengaud; C. Augier; A. Benoit; L. Bergé; O. Besida; J. Blümer; A. Broniatowski; V. Brudanin; A. Chantelauze; M. Chapellier; G. Chardin; F. Charlieux; S. Collin; X. Defay; M. De Jésus; P. Di Stefano; Y. Dolgorouki; J. Domange; L. Dumoulin; K. Eitel; J. Gascon; G. Gerbier; M. Gros; M. Hannawald; S. Hervé; A. Juillard; H. Kluck; R. Lemrani; P. Loaiza; A. Lubashevskiy; S. Marnieros; X.-F. Navick; E. Olivieri; P. Pari; B. Paul; S. Rozov; V. Sanglard; S. Scorza; S. Semikh; A. S. Torrentó-Coello; L. Vagneron; M.-A. Verdier; E. Yakushev
2010-01-01
Muon-induced neutrons constitute a prominent background component in a number of low count rate experiments, namely direct searches for dark matter. In this work we describe a neutron detector to measure this background in an underground laboratory, the Laboratoire Souterrain de Modane. The system is based on 1m3 of Gd-loaded scintillator and it is linked with the muon veto of
Stable computation of search directions for near-degenerate linear programming problems
Hough
1997-01-01
In this paper, we examine stability issues that arise when computing search directions (Î´x, Î´y, Î´ s) for a primal-dual path-following interior point method for linear programming. The dual step Î´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
ArDM: a ton-scale LAr detector for direct Dark Matter searches
A. Marchionni; C. Amsler; A. Badertscher; V. Boccone; A. Bueno; M. C. Carmona-Benitez; J. Coleman; W. Creus; A. Curioni; M. Daniel; E. J. Dawe; U. Degunda; A. Gendotti; L. Epprecht; S. Horikawa; L. Kaufmann; L. Knecht; M. Laffranchi; C. Lazzaro; P. K. Lightfoot; D. Lussi; J. Lozano; K. Mavrokoridis; A. Melgarejo; P. Mijakowski; G. Natterer; S. Navas-Concha; P. Otyugova; M. de Prado; P. Przewlocki; C. Regenfus; F. Resnati; M. Robinson; J. Rochet; L. Romero; E. Rondio; A. Rubbia; L. Scotto-Lavina; N. J. C. Spooner; T. Strauss; C. Touramanis; J. Ulbricht; T. Viant
2011-01-01
The Argon Dark Matter (ArDM-1t) experiment is a ton-scale liquid argon (LAr) double-phase time projection chamber designed for direct Dark Matter searches. Such a device allows to explore the low energy frontier in LAr with a charge imaging detector. The ionization charge is extracted from the liquid into the gas phase and there amplified by the use of a Large
ArDM: a ton-scale LAr detector for direct Dark Matter searches
A. Marchionni; C. Amsler; A. Badertscher; V. Boccone; A. Bueno; M. C. Carmona-Benitez; J. Coleman; W. Creus; A. Curioni; M. Daniel; E. J. Dawe; U. Degunda; A. Gendotti; L. Epprecht; S. Horikawa; L. Kaufmann; L. Knecht; M. Laffranchi; C. Lazzaro; P. K. Lightfoot; D. Lussi; J. Lozano; K. Mavrokoridis; A. Melgarejo; P. Mijakowski; G. Natterer; S. Navas-Concha; P. Otyugova; M. de Prado; P. Przewlocki; C. Regenfus; F. Resnati; M. Robinson; J. Rochet; L. Romero; E. Rondio; A. Rubbia; L. Scotto-Lavina; N. J. C. Spooner; T. Strauss; C. Touramanis; J. Ulbricht; T. Viant
2010-01-01
The Argon Dark Matter (ArDM-1t) experiment is a ton-scale liquid argon (LAr)\\u000adouble-phase time projection chamber designed for direct Dark Matter searches.\\u000aSuch a device allows to explore the low energy frontier in LAr with a charge\\u000aimaging detector. The ionization charge is extracted from the liquid into the\\u000agas phase and there amplified by the use of a Large
Burger, J R
2008-01-01
By way of explaining how a brain works logically, human associative memory is modeled with logical and memory neurons, corresponding to standard digital circuits. The resulting cognitive architecture incorporates basic psychological elements such as short term and long term memory. Novel to the architecture are memory searches using cues chosen pseudorandomly from short term memory. Recalls alternated with sensory images, many tens per second, are analyzed subliminally as an ongoing process, to determine a direction of attention in short term memory.
Search for Coincidences in Time and Arrival Direction of Auger Data with Astrophysical Transients
Anchordoqui, Luis; Collaboration, for the Pierre Auger
2007-06-01
The data collected by the Pierre Auger Observatory are analyzed to search for coincidences between the arrival directions of high-energy cosmic rays and the positions in the sky of astrophysical transients. Special attention is directed towards gamma ray observations recorded by NASA's Swift mission, which have an angular resolution similar to that of the Auger surface detectors. In particular, we check our data for evidence of a signal associated with the giant flare that came from the soft gamma repeater 1806-20 on December 27, 2004.
Abidi, Mongi A.
1 DIRECT SEARCH OF TIME DELAY IN BEAMFORMING APPLICATIONS Juan R. Aguilar , Miguel Arias, Ph direct search optimization methods for the time delay determination in beamforming applications. Since direct search methods in the determination of the time delay between two discrete time series. Since each
The SEARCH for Diabetes in Youth study: rationale, findings, and future directions.
Hamman, Richard F; Bell, Ronny A; Dabelea, Dana; D'Agostino, Ralph B; Dolan, Lawrence; Imperatore, Giuseppina; Lawrence, Jean M; Linder, Barbara; Marcovina, Santica M; Mayer-Davis, Elizabeth J; Pihoker, Catherine; Rodriguez, Beatriz L; Saydah, Sharon
2014-12-01
The SEARCH for Diabetes in Youth (SEARCH) study was initiated in 2000, with funding from the Centers for Disease Control and Prevention and support from the National Institute of Diabetes and Digestive and Kidney Diseases, to address major knowledge gaps in the understanding of childhood diabetes. SEARCH is being conducted at five sites across the U.S. and represents the largest, most diverse study of diabetes among U.S. youth. An active registry of youth diagnosed with diabetes at age <20 years allows the assessment of prevalence (in 2001 and 2009), annual incidence (since 2002), and trends by age, race/ethnicity, sex, and diabetes type. Prevalence increased significantly from 2001 to 2009 for both type 1 and type 2 diabetes in most age, sex, and race/ethnic groups. SEARCH has also established a longitudinal cohort to assess the natural history and risk factors for acute and chronic diabetes-related complications as well as the quality of care and quality of life of persons with diabetes from diagnosis into young adulthood. Many youth with diabetes, particularly those from low-resourced racial/ethnic minority populations, are not meeting recommended guidelines for diabetes care. Markers of micro- and macrovascular complications are evident in youth with either diabetes type, highlighting the seriousness of diabetes in this contemporary cohort. This review summarizes the study methods, describes key registry and cohort findings and their clinical and public health implications, and discusses future directions. PMID:25414389
arXiv:hep-ph/0412300v121Dec2004 Neutrinoless double beta decay and direct searches for neutrino mass
Piepke, Andreas G.
arXiv:hep-ph/0412300v121Dec2004 Neutrinoless double beta decay and direct searches for neutrino (Dated: December 22, 2004) Study of the neutrinoless double beta decay and searches for the manifestation and recommendations on them. · Observation of the neutrinoless double-beta decay (0) would prove that the total lepton
Reichhart, Lea
2013-11-28
Astrophysical observations give convincing evidence for a vast non-baryonic component, the so-called dark matter, accounting for over 20% of the overall content of our Universe. Direct dark matter search experiments ...
Search for direct CP violation in singly Cabibbo-suppressed D±?K+K-?± decays
NASA Astrophysics Data System (ADS)
Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Brown, D. N.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Koch, H.; Schroeder, T.; Asgeirsson, D. J.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; So, R. Y.; Khan, A.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Kravchenko, E. A.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Yushkov, A. N.; Bondioli, M.; Kirkby, D.; Lankford, A. J.; Mandelkern, M.; Atmacan, H.; Gary, J. W.; Liu, F.; Long, O.; Vitug, G. M.; Campagnari, C.; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; West, C. A.; Eisner, A. M.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Schumm, B. A.; Seiden, A.; Chao, D. S.; Cheng, C. H.; Echenard, B.; Flood, K. T.; Hitlin, D. G.; Ongmongkolkul, P.; Porter, F. C.; Rakitin, A. Y.; Andreassen, R.; Huard, Z.; Meadows, B. T.; Sokoloff, M. D.; Sun, L.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Spaan, B.; Schubert, K. R.; Schwierz, R.; Bernard, D.; Verderi, M.; Clark, P. J.; Playfer, S.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cibinetto, G.; Fioravanti, E.; Garzia, I.; Luppi, E.; Piemontese, L.; Santoro, V.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Bhuyan, B.; Prasad, V.; Lee, C. L.; Morii, M.; Edwards, A. J.; Adametz, A.; Uwer, U.; Lacker, H. M.; Lueck, T.; Dauncey, P. D.; Mallik, U.; Chen, C.; Cochran, J.; Meyer, W. T.; Prell, S.; Rubin, A. E.; Gritsan, A. V.; Guo, Z. J.; Arnaud, N.; Davier, M.; Derkach, D.; Grosdidier, G.; Le Diberder, F.; Lutz, A. M.; Malaescu, B.; Roudeau, P.; Schune, M. H.; Stocchi, A.; Wormser, G.; Lange, D. J.; Wright, D. M.; Chavez, C. A.; Coleman, J. P.; Fry, J. R.; Gabathuler, E.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Di Lodovico, F.; Sacco, R.; Sigamani, M.; Cowan, G.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Griessinger, K.; Hafner, A.; Prencipe, E.; Barlow, R. J.; Jackson, G.; Lafferty, G. D.; Behn, E.; Cenci, R.; Hamilton, B.; Jawahery, A.; Roberts, D. A.; Dallapiccola, C.; Cowan, R.; Dujmic, D.; Sciolla, G.; Cheaib, R.; Lindemann, D.; Patel, P. M.; Robertson, S. H.; Biassoni, P.; Neri, N.; Palombo, F.; Stracka, S.; Cremaldi, L.; Godang, R.; Kroeger, R.; Sonnek, P.; Summers, D. J.; Nguyen, X.; Simard, M.; Taras, P.; De Nardo, G.; Monorchio, D.; Onorato, G.; Sciacca, C.; Martinelli, M.; Raven, G.; Jessop, C. P.; LoSecco, J. M.; Wang, W. F.; Honscheid, K.; Kass, R.; Brau, J.; Frey, R.; Sinev, N. B.; Strom, D.; Torrence, E.; Feltresi, E.; Gagliardi, N.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simi, G.; Simonetto, F.; Stroili, R.; Akar, S.; Ben-Haim, E.; Bomben, M.; Bonneaud, G. R.; Briand, H.; Calderini, G.; Chauveau, J.; Hamon, O.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Sitt, S.; Biasini, M.; Manoni, E.; Pacetti, S.; Rossi, A.; Angelini, C.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Cervelli, A.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Oberhof, B.; Paoloni, E.; Perez, A.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Anulli, F.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Li Gioi, L.; Mazzoni, M. A.; Piredda, G.; Bünger, C.; Grünberg, O.; Hartmann, T.; Leddig, T.; Voß, C.; Waldi, R.; Adye, T.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Hamel de Monchenault, G.; Vasseur, G.; Yèche, Ch.; Aston, D.; Bard, D. J.; Bartoldus, R.; Benitez, J. F.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Ebert, M.; Field, R. C.; Franco Sevilla, M.; Fulsom, B. G.; Gabareen, A. M.; Graham, M. T.; Grenier, P.; Hast, C.; Innes, W. R.; Kelsey, M. H.; Kim, P.; Kocian, M. L.; Leith, D. W. G. S.; Lewis, P.; Lindquist, B.; Luitz, S.; Luth, V.; Lynch, H. L.; MacFarlane, D. B.; Muller, D. R.; Neal, H.; Nelson, S.; Perl, M.; Pulliam, T.; Ratcliff, B. N.; Roodman, A.; Salnikov, A. A.; Schindler, R. H.; Snyder, A.; Su, D.; Sullivan, M. K.; Va'vra, J.; Wagner, A. P.; Wisniewski, W. J.; Wittgen, M.; Wright, D. H.; Wulsin, H. W.; Young, C. C.; Ziegler, V.; Park, W.; Purohit, M. V.; White, R. M.; Wilson, J. R.; Randle-Conde, A.; Sekula, S. J.; Bellis, M.; Burchat, P. R.; Miyashita, T. S.; Puccio, E. M. T.; Alam, M. S.; Ernst, J. A.; Gorodeisky, R.; Guttman, N.; Peimer, D. R.; Soffer, A.; Lund, P.; Spanier, S. M.; Ritchie, J. L.; Ruland, A. M.; Schwitters, R. F.; Wray, B. C.; Izen, J. M.; Lou, X. C.; Bianchi, F.; Gamba, D.; Zambito, S.; Lanceri, L.; Vitale, L.; Martinez-Vidal, F.; Oyanguren, A.; Villanueva-Perez, P.; Ahmed, H.
2013-03-01
We report on a search for direct CP violation in the singly Cabibbo-suppressed decay D+?K+K-?+ using a data sample of 476fb-1 of e+e- annihilation data accumulated with the BABAR detector at the SLAC PEP-II electron-positron collider, running at and just below the energy of the ?(4S) resonance. The integrated CP-violating decay rate asymmetry ACP is determined to be (0.37±0.30±0.15)%. Model-independent and model-dependent Dalitz plot analysis techniques are used to search for CP-violating asymmetries in the various intermediate states. We find no evidence for CP-violation asymmetry.
Intrinsic neutron background of nuclear emulsions for directional Dark Matter searches
Aleksandrov, A; Buonaura, A; Consiglio, L; D'Ambrosio, N; De Lellis, G; Di Crescenzo, A; Di Marco, N; Di Vacri, M L; Furuya, S; Galati, G; Gentile, V; Katsuragawa, T; Laubenstein, M; Lauria, A; Loverre, P F; Machii, S; Monacelli, P; Montesi, M C; Naka, T; Pupilli, F; Rosa, G; Sato, O; Tioukov, V; Umemoto, A; Yoshimoto, M
2015-01-01
Recent developments of the nuclear emulsion technology led to the production of films with nanometric silver halide grains suitable to track low energy nuclear recoils with submicrometric length. This improvement opens the way to a directional Dark Matter detection, thus providing an innovative and complementary approach to the on-going WIMP searches. An important background source for these searches is represented by neutron-induced nuclear recoils that can mimic the WIMP signal. In this paper we provide an estimation of the contribution to this background from the intrinsic radioactive contamination of nuclear emulsions. We also report the induced background as a function of the read-out threshold, by using a GEANT4 simulation of the nuclear emulsion, showing that it amounts to about 0.02 neutrons per year per kilogram, fully compatible with the design of a 10 kg$\\times$year exposure.
Light neutralino dark matter: direct/indirect detection and collider searches
NASA Astrophysics Data System (ADS)
Han, Tao; Liu, Zhen; Su, Shufang
2014-08-01
We study the neutralino being the Lightest Supersymmetric Particle (LSP) as a cold Dark Matter (DM) candidate with a mass less than 40 GeV in the framework of the Next-to-Minimal-Supersymmetric-Standard-Model (NMSSM). We find that with the current collider constraints from LEP, the Tevatron and the LHC, there are three types of light DM solutions consistent with the direct/indirect searches as well as the relic abundance considerations: ( i) A 1, H 1-funnels, ( ii) stau coannihilation and ( iii) sbottom coannihilation. Type-( i) may take place in any theory with a light scalar (or pseudo-scalar) near the LSP pair threshold; while Type-( ii) and ( iii) could occur in the framework of Minimal-Supersymmetric-Standard-Model (MSSM) as well. We present a comprehensive study on the properties of these solutions and point out their immediate relevance to the experiments of the underground direct detection such as superCDMS and LUX/LZ, and the astro-physical indirect search such as Fermi-LAT. We also find that the decays of the SM-like Higgs boson may be modified appreciably and the new decay channels to the light SUSY particles may be sizable. The new light CP-even and CP-odd Higgs bosons will decay to a pair of LSPs as well as other observable final states, leading to interesting new Higgs phenomenology at colliders. For the light sfermion searches, the signals would be very challenging to observe at the LHC given the current bounds. However, a high energy and high luminosity lepton collider, such as the ILC, would be able to fully cover these scenarios by searching for events with large missing energy plus charged tracks or displaced vertices.
The degenerate scenario in the NMSSM: Direct singlino-like neutralino searches with a gravitino LSP
Grigoris Panotopoulos
2011-03-01
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 to work. 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.
NASA Astrophysics Data System (ADS)
Chen, Yung-Yao; Hong, Sheng-Yi; Chen, Kai-Wen
2015-03-01
This paper proposes a novel message-embedded halftoning scheme that is based on orientation modulation (OM) encoding. To achieve high image quality, we employ a human visual system (HVS)-based error metric between the continuous-tone image and a data-embedded halftone, and integrate a modified direct binary search (DBS) framework into the proposed message-embedded halftoning method. The modified DBS framework ensures that the resulting data-embedded halftones have optimal image quality from the viewpoint of the HVS.
A directed search for gravitational waves from Scorpius X-1 with initial LIGO
The LIGO Scientific Collaboration; the Virgo Collaboration; J. Aasi; B. P. Abbott; R. Abbott; T. Abbott; M. R. Abernathy; F. Acernese; K. Ackley; C. Adams; T. Adams; T. Adams; P. Addesso; R. X. Adhikari; V. Adya; C. Affeldt; M. Agathos; K. Agatsuma; N. Aggarwal; O. D. Aguiar; A. Ain; P. Ajith; A. Alemic; B. Allen; A. Allocca; D. Amariutei; S. B. Anderson; W. G. Anderson; K. Arai; M. C. Araya; C. Arceneaux; J. S. Areeda; G. Ashton; S. Ast; S. M. Aston; P. Astone; P. Aufmuth; C. Aulbert; B. E. Aylott; S. Babak; P. T. Baker; F. Baldaccini; G. Ballardin; S. W. Ballmer; J. C. Barayoga; M. Barbet; S. Barclay; B. C. Barish; D. Barker; F. Barone; B. Barr; L. Barsotti; M. Barsuglia; J. Bartlett; M. A. Barton; I. Bartos; R. Bassiri; A. Basti; J. C. Batch; Th. S. Bauer; C. Baune; V. Bavigadda; B. Behnke; M. Bejger; C. Belczynski; A. S. Bell; C. Bell; M. Benacquista; J. Bergman; G. Bergmann; C. P. L. Berry; D. Bersanetti; A. Bertolini; J. Betzwieser; S. Bhagwat; R. Bhandare; I. A. Bilenko; G. Billingsley; J. Birch; S. Biscans; M. Bitossi; C. Biwer; M. A. Bizouard; J. K. Blackburn; L. Blackburn; C. D. Blair; D. Blair; S. Bloemen; O. Bock; T. P. Bodiya; M. Boer; G. Bogaert; P. Bojtos; C. Bond; F. Bondu; L. Bonelli; R. Bonnand; R. Bork; M. Born; V. Boschi; Sukanta Bose; C. Bradaschia; P. R. Brady; V. B. Braginsky; M. Branchesi; J. E. Brau; T. Briant; D. O. Bridges; A. Brillet; M. Brinkmann; V. Brisson; A. F. Brooks; D. A. Brown; D. D. Brown; N. M. Brown; S. Buchman; A. Buikema; T. Bulik; H. J. Bulten; A. Buonanno; D. Buskulic; C. Buy; L. Cadonati; G. Cagnoli; J. Calderón Bustillo; E. Calloni; J. B. Camp; K. C. Cannon; J. Cao; C. D. Capano; F. Carbognani; S. Caride; S. Caudill; M. Cavaglià; F. Cavalier; R. Cavalieri; G. Cella; C. Cepeda; E. Cesarini; R. Chakraborty; T. Chalermsongsak; S. J. Chamberlin; S. Chao; P. Charlton; E. Chassande-Mottin; Y. Chen; A. Chincarini; A. Chiummo; H. S. Cho; M. Cho; J. H. Chow; N. Christensen; Q. Chu; S. Chua; S. Chung; G. Ciani; F. Clara; J. A. Clark; F. Cleva; E. Coccia; P. -F. Cohadon; A. Colla; C. Collette; M. Colombini; L. Cominsky; M. Constancio, Jr.; A. Conte; D. Cook; T. R. Corbitt; N. Cornish; A. Corsi; C. A. Costa; M. W. Coughlin; J. -P. Coulon; S. Countryman; P. Couvares; D. M. Coward; M. J. Cowart; D. C. Coyne; R. Coyne; K. Craig; J. D. E. Creighton; T. D. Creighton; J. Cripe; S. G. Crowder; A. Cumming; L. Cunningham; E. Cuoco; C. Cutler; K. Dahl; T. Dal Canton; M. Damjanic; S. L. Danilishin; S. D'Antonio; K. Danzmann; L. Dartez; V. Dattilo; I. Dave; H. Daveloza; M. Davier; G. S. Davies; E. J. Daw; R. Day; D. DeBra; G. Debreczeni; J. Degallaix; M. De Laurentis; S. Deléglise; W. Del Pozzo; T. Denker; T. Dent; H. Dereli; V. Dergachev; R. De Rosa; R. T. DeRosa; R. DeSalvo; S. Dhurandhar; M. Díaz; L. Di Fiore; A. Di Lieto; I. Di Palma; A. Di Virgilio; G. Dojcinoski; V. Dolique; E. Dominguez; F. Donovan; K. L. Dooley; S. Doravari; R. Douglas; T. P. Downes; M. Drago; J. C. Driggers; Z. Du; M. Ducrot; S. Dwyer; T. Eberle; T. Edo; M. Edwards; M. Edwards; A. Effler; H. -B. Eggenstein; P. Ehrens; J. Eichholz; S. S. Eikenberry; R. Essick; T. Etzel; M. Evans; T. Evans; M. Factourovich; V. Fafone; S. Fairhurst; X. Fan; Q. Fang; S. Farinon; B. Farr; W. M. Farr; M. Favata; M. Fays; H. Fehrmann; M. M. Fejer; D. Feldbaum; I. Ferrante; E. C. Ferreira; F. Ferrini; F. Fidecaro; I. Fiori; R. P. Fisher; R. Flaminio; J. -D. Fournier; S. Franco; S. Frasca; F. Frasconi; Z. Frei; A. Freise; R. Frey; T. T. Fricke; P. Fritschel; V. V. Frolov; S. Fuentes-Tapia; P. Fulda; M. Fyffe; J. R. Gair; L. Gammaitoni; S. Gaonkar; F. Garufi; A. Gatto; N. Gehrels; G. Gemme; B. Gendre; E. Genin; A. Gennai; L. Á. Gergely; S. Ghosh; J. A. Giaime; K. D. Giardina; A. Giazotto; J. Gleason; E. Goetz; R. Goetz; L. Gondan; G. González; N. Gordon; M. L. Gorodetsky; S. Gossan; S. Goßler; R. Gouaty; C. Gräf; P. B. Graff; M. Granata; A. Grant; S. Gras; C. Gray; R. J. S. Greenhalgh; A. M. Gretarsson; P. Groot; H. Grote; S. Grunewald; G. M. Guidi; C. J. Guido; X. Guo; K. Gushwa; E. K. Gustafson; R. Gustafson; J. Hacker; E. D. Hall; G. Hammond; M. Hanke; J. Hanks; C. Hanna; M. D. Hannam; J. Hanson; T. Hardwick; J. Harms; G. M. Harry; I. W. Harry; M. Hart; M. T. Hartman; C. -J. Haster; K. Haughian; S. Hee; A. Heidmann; M. Heintze; G. Heinzel; H. Heitmann; P. Hello; G. Hemming; M. Hendry; I. S. Heng; A. W. Heptonstall; M. Heurs; M. Hewitson; S. Hild; D. Hoak; K. A. Hodge; D. Hofman; S. E. Hollitt; K. Holt; P. Hopkins; D. J. Hosken; J. Hough; E. Houston; E. J. Howell; Y. M. Hu; E. Huerta; B. Hughey; S. Husa; S. H. Huttner; M. Huynh; T. Huynh-Dinh; A. Idrisy; N. Indik; D. R. Ingram; R. Inta; G. Islas; J. C. Isler; T. Isogai; B. R. Iyer; K. Izumi; M. Jacobson; H. Jang; P. Jaranowski; S. Jawahar; Y. Ji; F. Jiménez-Forteza; W. W. Johnson; D. I. Jones; R. Jones; R. J. G. Jonker; L. Ju; Haris K; V. Kalogera
2014-12-01
We present results of a search for continuously-emitted gravitational radiation, directed at the brightest low-mass X-ray binary, Scorpius X-1. Our semi-coherent analysis covers 10 days of LIGO S5 data ranging from 50-550 Hz, and performs an incoherent sum of coherent $\\mathcal{F}$-statistic power distributed amongst frequency-modulated orbital sidebands. All candidates not removed at the veto stage were found to be consistent with noise at a 1% false alarm rate. We present Bayesian 95% confidence upper limits on gravitational-wave strain amplitude using two different prior distributions: a standard one, with no a priori assumptions about the orientation of Scorpius X-1; and an angle-restricted one, using a prior derived from electromagnetic observations. Median strain upper limits of 1.3e-24 and 8e-25 are reported at 150 Hz for the standard and angle-restricted searches respectively. This proof of principle analysis was limited to a short observation time by unknown effects of accretion on the intrinsic spin frequency of the neutron star, but improves upon previous upper limits by factors of ~1.4 for the standard, and 2.3 for the angle-restricted search at the sensitive region of the detector.
A directed search for continuous Gravitational Waves from the Galactic Center
The LIGO Scientific Collaboration; The Virgo Collaboration; J. Aasi; J. Abadie; B. P. Abbott; R. Abbott; T. Abbott; M. R. Abernathy; T. Accadia; F. Acernese; C. Adams; T. Adams; R. X. Adhikari; C. Affeldt; M. Agathos; N. Aggarwal; O. D. Aguiar; P. Ajith; B. Allen; A. Allocca; E. Amador Ceron; D. Amariutei; R. A. Anderson; S. B. Anderson; W. G. Anderson; K. Arai; M. C. Araya; C. Arceneaux; J. Areeda; S. Ast; S. M. Aston; P. Astone; P. Aufmuth; C. Aulbert; L. Austin; B. E. Aylott; S. Babak; P. T. Baker; G. Ballardin; S. W. Ballmer; J. C. Barayoga; D. Barker; S. H. Barnum; F. Barone; B. Barr; L. Barsotti; M. Barsuglia; M. A. Barton; I. Bartos; R. Bassiri; A. Basti; J. Batch; J. Bauchrowitz; Th. S. Bauer; M. Bebronne; B. Behnke; M. Bejger; M. G. Beker; A. S. Bell; C. Bell; I. Belopolski; G. Bergmann; J. M. Berliner; A. Bertolini; D. Bessis; J. Betzwieser; P. T. Beyersdorf; T. Bhadbhade; I. A. Bilenko; G. Billingsley; J. Birch; M. Bitossi; M. A. Bizouard; E. Black; J. K. Blackburn; L. Blackburn; D. Blair; M. Blom; O. Bock; T. P. Bodiya; M. Boer; C. Bogan; C. Bond; F. Bondu; L. Bonelli; R. Bonnand; R. Bork; M. Born; S. Bose; L. Bosi; J. Bowers; C. Bradaschia; P. R. Brady; V. B. Braginsky; M. Branchesi; C. A. Brannen; J. E. Brau; J. Breyer; T. Briant; D. O. Bridges; A. Brillet; M. Brinkmann; V. Brisson; M. Britzger; A. F. Brooks; D. A. Brown; D. D. Brown; F. Brückner; T. Bulik; H. J. Bulten; A. Buonanno; D. Buskulic; C. Buy; R. L. Byer; L. Cadonati; G. Cagnoli; J. Calderón Bustillo; E. Calloni; J. B. Camp; P. Campsie; K. C. Cannon; B. Canuel; J. Cao; C. D. Capano; F. Carbognani; L. Carbone; S. Caride; A. Castiglia; S. Caudill; M. Cavagliá; F. Cavalier; R. Cavalieri; G. Cella; C. Cepeda; E. Cesarini; R. Chakraborty; T. Chalermsongsak; S. Chao; P. Charlton; E. Chassande-Mottin; X. Chen; Y. Chen; A. Chincarini; A. Chiummo; H. S. Cho; J. Chow; N. Christensen; Q. Chu; S. S. Y. Chua; S. Chung; G. Ciani; F. Clara; D. E. Clark; J. A. Clark; F. Cleva; E. Coccia; P. -F. Cohadon; A. Colla; M. Colombini; M. Constancio Jr; A. Conte; R. Conte; D. Cook; T. R. Corbitt; M. Cordier; N. Cornish; A. Corsi; C. A. Costa; M. W. Coughlin; J. -P. Coulon; S. Countryman; P. Couvares; D. M. Coward; M. Cowart; D. C. Coyne; K. Craig; J. D. E. Creighton; T. D. Creighton; S. G. Crowder; A. Cumming; L. Cunningham; E. Cuoco; K. Dahl; T. Dal Canton; M. Damjanic; S. L. Danilishin; S. D'Antonio; K. Danzmann; V. Dattilo; B. Daudert; H. Daveloza; M. Davier; G. S. Davies; E. J. Daw; R. Day; T. Dayanga; R. De Rosa; G. Debreczeni; J. Degallaix; W. Del Pozzo; E. Deleeuw; S. Deléglise; T. Denker; T. Dent; H. Dereli; V. Dergachev; R. DeRosa; R. DeSalvo; S. Dhurandhar; L. Di Fiore; A. Di Lieto; I. Di Palma; A. Di Virgilio; M. Díaz; A. Dietz; K. Dmitry; F. Donovan; K. L. Dooley; S. Doravari; M. Drago; R. W. P. Drever; J. C. Driggers; Z. Du; J. -C. Dumas; S. Dwyer; T. Eberle; M. Edwards; A. Effler; P. Ehrens; J. Eichholz; S. S. Eikenberry; G. Endröczi; R. Essick; T. Etzel; K. Evans; M. Evans; T. Evans; M. Factourovich; V. Fafone; S. Fairhurst; Q. Fang; B. Farr; W. Farr; M. Favata; D. Fazi; H. Fehrmann; D. Feldbaum; I. Ferrante; F. Ferrini; F. Fidecaro; L. S. Finn; I. Fiori; R. Fisher; R. Flaminio; E. Foley; S. Foley; E. Forsi; L. A. Forte; N. Fotopoulos; J. -D. Fournier; S. Franco; S. Frasca; F. Frasconi; M. Frede; M. Frei; Z. Frei; A. Freise; R. Frey; T. T. Fricke; P. Fritschel; V. V. Frolov; M. -K. Fujimoto; P. Fulda; M. Fyffe; J. Gair; L. Gammaitoni; J. Garcia; F. Garufi; N. Gehrels; G. Gemme; E. Genin; A. Gennai; L. Gergely; S. Ghosh; J. A. Giaime; S. Giampanis; K. D. Giardina; A. Giazotto; S. Gil-Casanova; C. Gill; J. Gleason; E. Goetz; R. Goetz; L. Gondan; G. González; N. Gordon; M. L. Gorodetsky; S. Gossan; S. Goßler; R. Gouaty; C. Graef; P. B. Graff; M. Granata; A. Grant; S. Gras; C. Gray; R. J. S. Greenhalgh; A. M. Gretarsson; C. Griffo; H. Grote; K. Grover; S. Grunewald; G. M. Guidi; C. Guido; K. E. Gushwa; E. K. Gustafson; R. Gustafson; B. Hall; E. Hall; D. Hammer; G. Hammond; M. Hanke; J. Hanks; C. Hanna; J. Hanson; J. Harms; G. M. Harry; I. W. Harry; E. D. Harstad; M. T. Hartman; K. Haughian; K. Hayama; J. Heefner; A. Heidmann; M. Heintze; H. Heitmann; P. Hello; G. Hemming; M. Hendry; I. S. Heng; A. W. Heptonstall; M. Heurs; S. Hild; D. Hoak; K. A. Hodge; K. Holt; M. Holtrop; T. Hong; S. Hooper; T. Horrom; D. J. Hosken; J. Hough; E. J. Howell; Y. Hu; Z. Hua; V. Huang; E. A. Huerta; B. Hughey; S. Husa; S. H. Huttner; M. Huynh; T. Huynh-Dinh; J. Iafrate; D. R. Ingram; R. Inta; T. Isogai; A. Ivanov; B. R. Iyer; K. Izumi; M. Jacobson; E. James; H. Jang; Y. J. Jang; P. Jaranowski; F. Jiménez-Forteza; W. W. Johnson; D. Jones; D. I. Jones; R. Jones; R. J. G. Jonker; L. Ju; Haris K; P. Kalmus; V. Kalogera; S. Kandhasamy; G. Kang; J. B. Kanner; M. Kasprzack; R. Kasturi; E. Katsavounidis; W. Katzman; H. Kaufer; K. Kaufman; K. Kawabe
2013-09-27
We present the results of a directed search for continuous gravitational waves from unknown, isolated neutron stars in the Galactic Center region, performed on two years of data from LIGO's fifth science run from two LIGO detectors. The search uses a semi-coherent approach, analyzing coherently 630 segments, each spanning 11.5 hours, and then incoherently combining the results of the single segments. It covers gravitational wave frequencies in a range from 78 to 496 Hz and a frequency-dependent range of first order spindown values down to -7.86 x 10^-8 Hz/s at the highest frequency. No gravitational waves were detected. We place 90% confidence upper limits on the gravitational wave amplitude of sources at the Galactic Center. Placing 90% confidence upper limits on the gravitational wave amplitude of sources at the Galactic Center, we reach ~3.35x10^-25 for frequencies near 150 Hz. These upper limits are the most constraining to date for a large-parameter-space search for continuous gravitational wave signals.
Searches for direct pair production of third generation squarks with the ATLAS detector
NASA Astrophysics Data System (ADS)
Pagacova, Martina
2015-05-01
Naturalness arguments for weak-scale supersymmetry favour supersymmetric partners of the third generation quarks with masses not too far from those of their Standard Model counterparts. If the masses of top and bottom squarks are below 1 TeV, the direct pair production cross-section is sufficient to produce observable signatures at the ATLAS detector and to probe various theoretical scenarios with the Large Hadron Collider (LHC) data at ?s = 8 TeV. The most recent ATLAS results from searches for direct stop and sbottom pair production are presented in these proceedings. No evidence of deviations from the Standard Model expectation has been observed, and the limits have been set on the masses of the top and bottom squarks.
ArDM: a ton-scale LAr detector for direct Dark Matter searches
NASA Astrophysics Data System (ADS)
Marchionni, A.; Amsler, C.; Badertscher, A.; Boccone, V.; Bueno, A.; Carmona-Benitez, M. C.; Coleman, J.; Creus, W.; Curioni, A.; Daniel, M.; Dawe, E. J.; Degunda, U.; Gendotti, A.; Epprecht, L.; Horikawa, S.; Kaufmann, L.; Knecht, L.; Laffranchi, M.; Lazzaro, C.; Lightfoot, P. K.; Lussi, D.; Lozano, J.; Mavrokoridis, K.; Melgarejo, A.; Mijakowski, P.; Natterer, G.; Navas-Concha, S.; Otyugova, P.; de Prado, M.; Przewlocki, P.; Regenfus, C.; Resnati, F.; Robinson, M.; Rochet, J.; Romero, L.; Rondio, E.; Rubbia, A.; Scotto-Lavina, L.; Spooner, N. J. C.; Strauss, T.; Touramanis, C.; Ulbricht, J.; Viant, T.
2011-07-01
The Argon Dark Matter (ArDM-1t) experiment is a ton-scale liquid argon (LAr) double-phase time projection chamber designed for direct Dark Matter searches. Such a device allows to explore the low energy frontier in LAr with a charge imaging detector. The ionization charge is extracted from the liquid into the gas phase and there amplified by the use of a Large Electron Multiplier in order to reduce the detection threshold. Direct detection of the ionization charge with fine spatial granularity, combined with a measurement of the amplitude and time evolution of the associated primary scintillation light, provide powerful tools for the identification of WIMP interactions against the background due to electrons, photons and possibly neutrons if scattering more than once. A one ton LAr detector is presently installed on surface at CERN to fully test all functionalities and it will be soon moved to an underground location. We will emphasize here the lessons learned from such a device for the design of a large LAr TPC for neutrino oscillation, proton decay and astrophysical neutrinos searches.
J. Parallel Distrib. Comput. 72 (2012) 666677 Contents lists available at SciVerse ScienceDirect
Qin, Xiao
2012-01-01
-as-a-Service (IaaS) cloud computing, computational resources are provided to remote users in the form of leases in the cloud system can improve the performance. When applying parallel processing in cloud computing Elsevier Inc. All rights reserved. 1. Introduction In cloud computing, a cloud is a cluster of distributed
Parallel acquisition of PN sequences in DS\\/SS systems
Kapil K. Chawla; Dilip V. Sarwate
1994-01-01
The authors investigate methods for the parallel acquisition of a PN sequence in a baseband direct sequence spread spectrum system. Four different schemes are considered: the optimal estimation scheme, the maximum-likelihood estimation scheme, a hypothesis-testing scheme that searches over all shifts, and a locally optimum detection scheme. Approximate expressions for the probability of error are derived for the first and
Parallel acquisition in mobile DS-CDMA systems
Roland R. Rick; Laurence B. Milstein
1997-01-01
This paper presents the performance of a direct sequence spread spectrum acquisition scheme in a mobile terrestrial communications system. The effects of fading, multipath, power control, shadowing, multiple access interference, out-of-cell interference, vehicle speed, voice activity, and sectorization are examined. The acquisition scheme uses noncoherent detection and a parallel search strategy. The analysis is done for the reverse link of
ZURNI OMAR; MOHAMED SULEIMAN
A new method called parallel R-point explicit block method for solving a single equation of higher order ordinary differential equation directly using a constant step size is developed. This method calculates the numerical solution at R point simultaneously and is parallel in nature. Computational advantages are presented by comparing the results obtained with the new method with that of the
PARALLEL STRINGS - PARALLEL UNIVERSES
Jim McDowall; Saft America
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
Impact of a Light Strange-Beauty Squark on B_s Mixing and Direct Search
Abdesslam Arhrib; Chun-Khiang Chua; Wei-Shu Hou
2001-09-25
If one has Abelian flavor symmetry, $s_R$-$b_R$ mixing could be near maximal. This can drive a "strange-beauty" squark ($\\widetilde{sb}_{1}$) to be rather light, but still evade the $b\\to s\\gamma$ constraint. Low energy constraints imply that all other superpartners are at TeV scale, except for a possibly light neutralino, $\\widetilde \\chi_1^0$. Whether light or heavy, the $\\widetilde{sb}_{1}$ can impact on the $B_s$ system: $\\Delta m_{B_s}$ and indirect CP phase, even for $B_s \\to \\phi\\gamma$. Direct search is similar to usual $\\tilde b \\to b\\widetilde \\chi_1^0$, but existing bounds are weakened by $\\widetilde{sb}_{1} \\to s\\widetilde \\chi_1^0$ possibility. All these effects could be studied soon at the Tevatron.
Low-energy recoils and energy scale in liquid xenon detector for direct dark matter searches
NASA Astrophysics Data System (ADS)
Wang, Lu; Mei, Dongming; Cubed Collaboration
2015-04-01
Liquid xenon has been proven to be a great detector medium for the direct search of dark matter. However, in the energy region of below 10 keV, the light yield and charge production are not fully understood due to the convolution of excitation, recombination and quenching. We have already studied a recombination model to explain the physics processes involved in liquid xenon. Work is continued on the average energy expended per electron-ion pair as a function of energy based on the cross sections for different type of scattering processes. In this paper, the results will be discussed in comparison with available experimental data using Birk's Law to understand how scintillation quenching contributes to the non-linear light yield for electron recoils with energy below 10 keV in liquid xenon. This work is supported by DOE Grant DE-FG02-10ER46709 and the state of South Dakota.
Hybrid halftoning using direct multi-bit search (DMS) screen algorithm
NASA Astrophysics Data System (ADS)
Chandu, Kartheek; Stanich, Mikel; Wu, Chai Wah; Trager, Barry
2014-01-01
In this paper we propose a mathematical framework for multi-bit aperiodic clustered dot halftoning based on the Direct Multi-bit Search (DMS) algorithm. A pixel validation map is provided to the DMS algorithm to guide the formation of homogeneous clusters. The DMS algorithm operates without any user defined guidance, iteratively choosing the best drop absorptance level. An array of valid pixels is computed after each iteration that restricts the selection of pixels available to the DMS algorithm, improving the dot clustering. This process is repeated throughout the entire range of gray levels to create a visually pleasing multi-bit halftone screen. The resultant mask exhibits smoother appearance and improved detail rendering, compared to conventional clustered dot halftoning. Much of the improvements originate from the improved sampling of the aperiodic hybrid screen designs.
Identifying sneutrino dark matter: Interplay between the LHC and direct search
Lee, Hye-Sung; Li Yingchuan [Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States)
2011-11-01
Under R parity, the lightest supersymmetric particle (LSP) is stable and may serve as a good dark matter candidate. The R parity can be naturally introduced with a gauge origin at the TeV scale. We go over why a TeV scale B-L gauge extension of the minimal supersymmetric standard model is one of the most natural, if not demanded, low energy supersymmetric models. In the presence of a TeV scale Abelian gauge symmetry, the (predominantly) right-handed sneutrino LSP can be a good dark matter candidate. Its identification at the LHC is challenging because it does not carry any standard model charge. We show how we can use the correlation between the LHC experiments (dilepton resonance signals) and the direct dark matter search experiments (such as CDMS and XENON) to identify the right-handed sneutrino LSP dark matter in the B-L extended minimal supersymmetric standard model.
Identifying sneutrino dark matter: Interplay between the LHC and direct search
Hye-Sung L.; Li, Y.
2011-11-03
Under R parity, the lightest supersymmetric particle (LSP) is stable and may serve as a good dark matter candidate. The R parity can be naturally introduced with a gauge origin at the TeV scale. We go over why a TeV scale B-L gauge extension of the minimal supersymmetric standard model is one of the most natural, if not demanded, low energy supersymmetric models. In the presence of a TeV scale Abelian gauge symmetry, the (predominantly) right-handed sneutrino LSP can be a good dark matter candidate. Its identification at the LHC is challenging because it does not carry any standard model charge. We show how we can use the correlation between the LHC experiments (dilepton resonance signals) and the direct dark matter search experiments (such as CDMS and XENON) to identify the right-handed sneutrino LSP dark matter in the B-L extended minimal supersymmetric standard model.
A detection system to measure muon-induced neutrons for direct dark matter searches
NASA Astrophysics Data System (ADS)
Kozlov, V. Yu.; Armengaud, E.; Augier, C.; Benoit, A.; Bergé, L.; Besida, O.; Blümer, J.; Broniatowski, A.; Brudanin, V.; Chantelauze, A.; Chapellier, M.; Chardin, G.; Charlieux, F.; Collin, S.; Defay, X.; De Jésus, M.; Di Stefano, P.; Dolgorouki, Y.; Domange, J.; Dumoulin, L.; Eitel, K.; Gascon, J.; Gerbier, G.; Gros, M.; Hannawald, M.; Hervé, S.; Juillard, A.; Kluck, H.; Lemrani, R.; Loaiza, P.; Lubashevskiy, A.; Marnieros, S.; Navick, X.-F.; Olivieri, E.; Pari, P.; Paul, B.; Rozov, S.; Sanglard, V.; Scorza, S.; Semikh, S.; Torrentó-Coello, A. S.; Vagneron, L.; Verdier, M.-A.; Yakushev, E.
2010-09-01
Muon-induced neutrons constitute a prominent background component in a number of low count rate experiments, namely direct searches for dark matter. In this work we describe a neutron detector to measure this background in an underground laboratory, the Laboratoire Souterrain de Modane. The system is based on 1 m 3 of Gd-loaded scintillator and it is linked with the muon veto of the EDELWEISS-II experiment for coincident muon detection. The system was installed in autumn 2008 and passed since then a number of commissioning tests proving its full functionality. The data-taking is continuously ongoing and a count rate of the order of 1 muon-induced neutron per day has been achieved.
Challenges and Benefits of Direct Policy Search in Advancing Multiobjective Reservoir Management
NASA Astrophysics Data System (ADS)
Castelletti, Andrea; Giuliani, Matteo; Zatarain-Salazar, Jazmin; Hermann, John; Pianosi, Francesca; Reed, Patrick
2015-04-01
Optimal management policies for water reservoir operation are generally designed via stochastic dynamic programming (SDP). Yet, the adoption of SDP in complex real-world problems is challenged by the three curses of dimensionality, of modeling, and of multiple objectives. These three curses considerably limit SDP's practical application. Alternatively, in this study, we focus on the use of evolutionary multi-objective direct policy search (EMODPS), a simulation-based optimization approach that combines direct policy search, nonlinear approximating networks and multi-objective evolutionary algorithms to design Pareto approximate operating policies for multi-purpose water reservoirs. Our analysis explores the technical and practical implications of using EMODPS through a careful diagnostic assessment of the EMODPS Pareto approximate solutions attained and the overall reliability of the policy design process. A key choice in the EMODPS approach is the selection of alternative formulations of the operating policies. In this study, we distinguish the relative performance of two widely used nonlinear approximating networks, namely Artificial Neural Networks and Radial Basis Functions, and we further compare them with SDP. Besides, we comparatively assess state-of-the-art multi-objective evolutionary algorithms (MOEAs) in terms of efficiency, effectiveness, reliability, and controllability. Our diagnostic results show that RBFs solutions are more effective that ANNs in designing Pareto approximate policies for several water reservoir systems. They also highlight that EMODPS is very challenging for modern MOEAs and that epsilon dominance is critical for attaining high levels of performance. Epsilon dominance algorithms epsilon-MOEA, epsilon-NSGAII and the auto adaptive Borg MOEA, are statistically superior for the class of problems considered.
Attentional Limitations in the Sensing of Motion Direction
Thomas Thornton; David L. Gilden
2001-01-01
Attentional constraints in the perceptual analysis of motion direction were examined using two independent paradigms: redundant target visual search and the analysis of fluctuations in discrimination accuracy at threshold. Results from both methods implied that directions of object motion are analyzed in parallel when those motions are translations, independent of the observer's line of sight. The registration of rotation direction
NASA Astrophysics Data System (ADS)
Sloan, Gregory James
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.
NASA Astrophysics Data System (ADS)
Karim, Fethallah; Seddiki, Omar
2010-05-01
In this paper, Direct Tabu Search (DTS) is proposed to synthesize the physical parameters of a fiber Bragg grating (FBG) numerically from its reflection response. A reflected spectrum is being calculated by using the Transfer Matrix Method (TMM). Direct search based strategies are used to direct a tabu search. These strategies are based on a new pattern search procedure called Adaptive Pattern Search (APS). In addition, the well-known Nelder-Mead (NME) algorithm is used as a local search method at the final stage of the optimization process. Direct Tabu Search (DTS) is applied for reconstruction of a raised cosine chirped fiber Bragg grating (CFBG) and a Gaussian multi channel fiber grating. The method is then used to synthesize a CFBG from its reflectivity taken at different temperatures. It gives a good estimate of the thermal expansion coefficient and the thermo-optic coefficient of the fiber.
Parallel algorithm development
Adams, T.F.
1996-06-01
Rapid changes in parallel computing technology are causing significant changes in the strategies being used for parallel algorithm development. One approach is simply to write computer code in a standard language like FORTRAN 77 or with the expectation that the compiler will produce executable code that will run in parallel. The alternatives are: (1) to build explicit message passing directly into the source code; or (2) to write source code without explicit reference to message passing or parallelism, but use a general communications library to provide efficient parallel execution. Application of these strategies is illustrated with examples of codes currently under development.
Stable computation of search directions for near-degenerate linear programming problems
Hough, P.D.
1997-03-01
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.
NASA Astrophysics Data System (ADS)
Chen, Hung-Ming; Chen, Po-Hung; Lin, Cheng-Tso; Liu, Ching-Chung
2012-11-01
An efficient algorithm named modified directional gradient descent searches to enhance the directional gradient descent search (DGDS) algorithm is presented to reduce computations. A modified search pattern with an adaptive threshold for early termination is applied to DGDS to avoid meaningless calculation after the searching point is good enough. A statistical analysis of best motion vector distribution is analyzed to decide the modified search pattern. Then a statistical model based on the characteristics of the block distortion information of the previous coded frame helps the early termination parameters selection, and a trade-off between the video quality and the computational complexity can be obtained. The simulation results show the proposed algorithm provides significant improvement in reducing the motion estimation (ME) by 17.81% of the average search points and 20% of ME time saving compared to the fast DGDS algorithm implemented in H.264/AVC JM 18.2 reference software according to different types of sequences, while maintaining a similar bit rate without losing picture quality.
Jeet, Justin; Schneider, Christian; Sullivan, Scott T; Rellergert, Wade G; Mirzadeh, Saed; Cassanho, A; Jenssen, H P; Tkalya, Eugene V; Hudson, Eric R
2015-06-26
We report the results of a direct search for the ^{229}Th (I^{?}=3/2^{+}?5/2^{+}) nuclear isomeric transition, performed by exposing ^{229}Th-doped LiSrAlF_{6} crystals to tunable vacuum-ultraviolet synchrotron radiation and observing any resulting fluorescence. We also use existing nuclear physics data to establish a range of possible transition strengths for the isomeric transition. We find no evidence for the thorium nuclear transition between 7.3 eV and 8.8 eV with transition lifetime (1-2) s???(2000-5600)??s. This measurement excludes roughly half of the favored transition search area and can be used to direct future searches. PMID:26197124
NASA Astrophysics Data System (ADS)
Jeet, Justin; Schneider, Christian; Sullivan, Scott T.; Rellergert, Wade G.; Mirzadeh, Saed; Cassanho, A.; Jenssen, H. P.; Tkalya, Eugene V.; Hudson, Eric R.
2015-06-01
We report the results of a direct search for the 229Th (I?=3 /2+?5 /2+ ) nuclear isomeric transition, performed by exposing 229Th -doped LiSrAlF6 crystals to tunable vacuum-ultraviolet synchrotron radiation and observing any resulting fluorescence. We also use existing nuclear physics data to establish a range of possible transition strengths for the isomeric transition. We find no evidence for the thorium nuclear transition between 7.3 eV and 8.8 eV with transition lifetime (1-2) s ?? ?(2000 - 5600 ) s . This measurement excludes roughly half of the favored transition search area and can be used to direct future searches.
Dark matter direct search rates in simulations of the Milky Way and Sagittarius stream
Purcell, Chris W.; Zentner, Andrew R.; Wang, Mei-Yu, E-mail: cpurcell@pitt.edu, E-mail: zentner@pitt.edu, E-mail: mew56@pitt.edu [Department of Physics and Astronomy and Pittsburgh Particle physics, Astrophysics and Cosmology Center (PITT PACC), University of Pittsburgh, Pittsburgh 15260 (United States)
2012-08-01
We analyze self-consistent N-body simulations of the Milky Way disk and the ongoing disruption of the Sagittarius dwarf satellite to study the effect of Sagittarius tidal debris on dark matter detection experiments. In agreement with significant previous work, we reiterate that the standard halo model is insufficient to describe the non-Maxwellian velocity distribution of the Milky Way halo in our equilibrium halo-only and halo/galaxy models, and offer suggestions for correcting for this discrepancy. More importantly, we emphasize that the dark matter component of the leading tidal arm of the Sagittarius dwarf is significantly more extended than the stellar component of the arm, and also that the dark matter and stellar streams are not necessarily coaxial and may be offset by several kpc at the point at which they impact the Galactic disk. This suggests that the dark matter component of the Sagittarius debris is likely to have a non-negligible influence on dark matter detection experiments even when the stellar debris is centered several kpc from the solar neighborhood. Relative to models without an infalling Sagittarius dwarf, the Sagittarius dark matter debris in our models induces an energy-dependent enhancement of direct search event rates of as much as ? 20–45%, an energy-dependent reduction in the amplitude of the annual modulation of the event rate by as much as a factor of two, a shift in the phase of the annual modulation by as much as ? 20 days, and a shift in the recoil energy at which the modulation reverses phase. These influences of Sagittarius are of general interest in the interpretation of dark matter searches, but may be particularly important in the case of relatively light (m{sub ?}?<20 GeV/c{sup 2}) dark matter because the Sagittarius stream impacts the solar system at high speed compared to the primary halo dark matter.
Science Parametrics for Missions to Search for Earth-like Exoplanets by Direct Imaging
NASA Astrophysics Data System (ADS)
Brown, Robert A.
2015-01-01
We use Nt , the number of exoplanets observed in time t, as a science metric to study direct-search missions like Terrestrial Planet Finder. In our model, N has 27 parameters, divided into three categories: 2 astronomical, 7 instrumental, and 18 science-operational. For various "27-vectors" of those parameters chosen to explore parameter space, we compute design reference missions to estimate Nt . Our treatment includes the recovery of completeness c after a search observation, for revisits, solar and antisolar avoidance, observational overhead, and follow-on spectroscopy. Our baseline 27-vector has aperture D = 16 m, inner working angle IWA = 0.039'', mission time t = 0-5 yr, occurrence probability for Earth-like exoplanets ? = 0.2, and typical values for the remaining 23 parameters. For the baseline case, a typical five-year design reference mission has an input catalog of ~4700 stars with nonzero completeness, ~1300 unique stars observed in ~2600 observations, of which ~1300 are revisits, and it produces N 1 ~ 50 exoplanets after one year and N 5 ~ 130 after five years. We explore offsets from the baseline for 10 parameters. We find that N depends strongly on IWA and only weakly on D. It also depends only weakly on zodiacal light for Z < 50 zodis, end-to-end efficiency for h > 0.2, and scattered starlight for ? < 10-10. We find that observational overheads, completeness recovery and revisits, solar and antisolar avoidance, and follow-on spectroscopy are all important factors in estimating N.
ERIC Educational Resources Information Center
Mattie, Harold D.
2000-01-01
An investigation explored the use of Holland's Self-Directed Search (SDS) by 185 readers and 152 non-readers (ages 14-21) with learning disabilities or mild mental retardation. The SDS was reliable for both readers and non-readers, able to validly measure preferences, and sensitive to preferences with respect to disability group membership.…
Yanikoglu, Berrin
-Preserving Multi-Keyword Search over Encrypted Cloud Data with Ranking Article Type: SI: Secure and Privacy is of a great concern, PIR protocols have been extensively studied in the past [26]. Cloud computing has storage and computation power tend to outsource their data and services to clouds. Clouds enable its
Mapping Unstructured Parallelism to Series-Parallel DAGs
Pan, Yan
Many parallel programming languages allow programmers to describe parallelism by using constructs such as fork/join. When executed, such programs can be modeled as directed graphs, with nodes representing a computation and ...
$H \\to \\gamma\\gamma$ search and direct photon pair production differential cross section
Bu, Xuebing; /Hefei, CUST
2010-06-01
At a hadron collider, diphoton ({gamma}{gamma}) production allows detailed studies of the Standard Model (SM), as well as as searches for new phenomena, such as new heavy resonances, extra spatial dimensions or cascade decays of heavy new particles. Within the SM, continuum {gamma}{gamma}+X production is characterized by a steeply-falling {gamma}{gamma} mass spectrum, on top of which a heavy resonance decaying into {gamma}{gamma} can potentially be observed. In particular, this is considered one of the most promising discovery channels for a SM Higgs boson at the LHC, despite the small branching ratio of BR (H {yields} {gamma}{gamma}) {approx} 0.2% for 110 < M{sub Higgs} < 140 GeV. At the Tevatron, the dominant SM Higgs boson production mechanism is gluon fusion, followed by associated production with a W or Z boson, and vector boson fusion. While the SM Higgs production rate at the Tevatron is not sufficient to observe it in the {gamma}{gamma} mode, the Hgg and H{gamma}{gamma} couplings, being loop-mediated, are particularly sensitive to new physics effects. Furthermore, in some models beyond the SM, for instance, fermiophobic Higgs, with no couplings to fermions, the BR (H {yields} {gamma}{gamma}) can be enhanced significantly relative to the SM prediction, while has the SM-like production cross sections except the gluon fusion is absent. In this thesis, we present a search for a light Higgs boson in the diphoton final state using 4.2 {+-} 0.3 fb{sup -1} of the D0 Run II data, collected at the Fermilab Tevatron collider from April 2002 to December 2008. Good agreement between the data and the SM background prediction is observed. Since there is no evidence for new physics, we set 95% C.L. limits on the production cross section times the branching ratio ({sigma} x BR(H {yields} {gamma}{gamma})) relative to the SM-like Higgs prediction for different assumed Higgs masses. The observed limits ({sigma}(limit)/{sigma}(SM)) range from 11.9 to 35.2 for Higgs masses from 100 to 150 GeV, while the expected limits range from 17.5 to 32.0. This search is also interpreted in the context of the particular fermiophobic Higgs model. The corresponding results have reached the same sensitivity as a single LEP experiement, setting a lower limit on the fermiophobic Higgs of M{sub h{sub f}} > 102.5 GeV (M{sub h{sub f}} > 107.5 GeV expected). We are slightly below the combined LEP limit (M{sub h{sub f}} > 109.7 GeV). We also provide access to the M{sub h{sub f}} > 125 GeV region which was inaccessible at LEP. During the study, we found the major and irreducible background direct {gamma}{gamma} (DPP) production is not well modelled by the current theoretical predictions: RESBOS, DIPHOX or PYTHIA. There is {approx}20% theoretical uncertainty for the predicted values. Thus, for our Higgs search, we use the side-band fitting method to estimate DPP contribution directly from the data events. Furthermore, DPP production is also a significant background in searches for new phenomena, such as new heavy resonances, extra spatial dimensions, or cascade decays of heavy new particles. Thus, precise measurements of the DPP cross sections for various kinematic variables and their theoretical understanding are extremely important for future Higgs and new phenomena searches. In this thesis, we also present a precise measurement of the DPP single differential cross sections as a function of the diphoton mass, the transverse momentum of the diphoton system, the azimuthal angle between the photons, and the polar scattering angle of the photons, as well as the double differential cross sections considering the last three kinematic variables in three diphoton mass bins, using 4.2 fb{sup -1} data. These results are the first of their kind at D0 Run II, and in fact the double differential measurements are the first of their kind at Tevatron. The results are compared with different perturbative QCD predictions and event generators.
Fermilab Experiment E871
Search for Direct CP Violation in Decays of Hyperons Y. C. Chen a , R. A. Burnstein b , A.S.A. The E871 (HyperCP) experiment at FNAL is searching for direct CP violation in decays of \\Xi \\Gamma (\\Xi more data which will improve the sensitivity to Ã? 1 \\Theta 10 \\Gamma4 . 1 Introduction CP violation has
Kalkan, Erol; Kwong, Neal S.
2012-01-01
According to regulatory building codes in United States (for example, 2010 California Building Code), at least two horizontal ground-motion components are required for three-dimensional (3D) response history analysis (RHA) of buildings. For sites within 5 km of an active fault, these records should be rotated to fault-normal/fault-parallel (FN/FP) directions, and two RHA analyses should be performed separately (when FN and then FP are aligned with the transverse direction of the structural axes). It is assumed that this approach will lead to two sets of responses that envelope the range of possible responses over all nonredundant rotation angles. This assumption is examined here using a 3D computer model of a six-story reinforced-concrete instrumented building subjected to an ensemble of bidirectional near-fault ground motions. Peak responses of engineering demand parameters (EDPs) were obtained for rotation angles ranging from 0° through 180° for evaluating the FN/FP directions. It is demonstrated that rotating ground motions to FN/FP directions (1) does not always lead to the maximum responses over all angles, (2) does not always envelope the range of possible responses, and (3) does not provide maximum responses for all EDPs simultaneously even if it provides a maximum response for a specific EDP.
Lu, H; Wang, R; Xiong, J; Xie, H; Kayser, B; Jia, Z P
2015-05-01
Despite decades of research, the exact pathogenic mechanisms underlying acute mountain sickness (AMS) are still poorly understood. This fact frustrates the search for novel pharmacological prophylaxis for AMS. The prevailing view is that AMS results from an insufficient physiological response to hypoxia and that prophylaxis should aim at stimulating the response. Starting off from the opposite hypothesis that AMS may be caused by an initial excessive response to hypoxia, we suggest that directly or indirectly blunting-specific parts of the response might provide promising research alternatives. This reasoning is based on the observations that (i) humans, once acclimatized, can climb Mt Everest experiencing arterial partial oxygen pressures (PaO2) as low as 25 mmHg without AMS symptoms; (ii) paradoxically, AMS usually develops at much higher PaO2 levels; and (iii) several biomarkers, suggesting initial activation of specific pathways at such PaO2, are correlated with AMS. Apart from looking for substances that stimulate certain hypoxia triggered effects, such as the ventilatory response to hypoxia, we suggest to also investigate pharmacological means aiming at blunting certain other specific hypoxia-activated pathways, or stimulating their agonists, in the quest for better pharmacological prophylaxis for AMS. PMID:25778288
Direct dark matter searches—Test of the Big Bounce Cosmology
NASA Astrophysics Data System (ADS)
Cheung, Yeuk-Kwan E.; Vergados, J. D.
2015-02-01
We consider the possibility of using dark matter particle's mass and its interaction cross section as a smoking gun signal of the existence of a Big Bounce at the early stage in the evolution of our currently observed universe. A study of dark matter production in the pre-bounce contraction and the post bounce expansion epochs of this universe reveals a new venue for achieving the observed relic abundance of our present universe. Specifically, it predicts a characteristic relation governing a dark matter mass and interaction cross section and a factor of 1/2 in thermally averaged cross section, as compared to the non-thermal production in standard cosmology, is needed for creating enough dark matter particle to satisfy the currently observed relic abundance because dark matter is being created during the pre-bounce contraction, in addition to the post-bounce expansion. As the production rate is lower than the Hubble expansion rate information of the bounce universe evolution is preserved. Therefore once the value of dark matter mass and interaction cross section are obtained by direct detection in laboratories, this alternative route becomes a signature prediction of the bounce universe scenario. This leads us to consider a scalar dark matter candidate, which if it is light, has important implications on dark matter searches.
Target dependence of the annual modulation in direct dark matter searches
NASA Astrophysics Data System (ADS)
Del Nobile, Eugenio; Gelmini, Graciela B.; Witte, Samuel J.
2015-06-01
Due to Earth's revolution around the Sun, the expected scattering rate in direct dark matter searches is annually modulated. This modulation is expected to differ between experiments when given as a function of recoil energy ER, e.g. due to the gravitational focusing effect of the Sun. A better variable to compare results among experiments employing different targets is the minimum speed vmin a dark matter particle must have to impart a recoil energy ER to a target nucleus. It is widely believed that the modulation expressed as a function of vmin is common to all experiments, irrespective of the dark matter distribution. We point out that the annual modulation as a function of vmin, and in particular the times at which the rate is maximum and minimum, could be very different depending on the detector material. This would be an indication of a scattering cross section with nonfactorizable velocity and target material dependence. Observing an annual modulation with at least two different target elements would be necessary to identify this type of cross section.
R&D Status of Nuclear Emulsion For Directional Dark Matter Search
T. Naka; M. Kimura; M. Nakamura; O. Sato; T. Nakano; T. Asada; Y. Tawara; Y. Suzuki
2011-09-22
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 150nm to 200nm with optical microscopy. Finally we demonstrated by using recoiled nuclei induced by 14.8MeV 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 degrees with optical microscopy to 17degrees with X-ray microscopy at the track length of range from 150nm to 250nm. We are developing the practical system and planning for start of the test running with prototype detector.
Joseph Krummenacher; Hermann J. Müller; Dieter Heller
2001-01-01
In two visual search experiments, the detection of singleton feature targets redundantly defined on multiple dimensions was\\u000a investigated. Targets differed from the distractors in orientation, color, or both (redundant targets). In Experiment 1, the\\u000a various target types were presented either in separate blocks or in random order within blocks. Reaction times to redundant\\u000a targets significantly violated therace model inequality (Miller,
Parallel MATLAB: Parallel For Loops
Crawford, T. Daniel
Parallel MATLAB: Parallel For Loops John Burkardt (FSU) Gene Cliff (AOE/ICAM - ecliff Research Computing ICAM: Interdisciplinary Center for Applied Mathematics 1 / 69 #12;MATLAB Parallel Example ODE SWEEP Example FMINCON Example Conclusion 2 / 69 #12;INTRO: Parallel MATLAB Parallel MATLAB
Richard B. Wattson; Laurence S. Rothman
1986-01-01
The Direct Numerical Diagonalization (DND) technique has been applied to the principal symmetric species of carbon dioxide. A three-dimensional formulation of the DND method has been implemented as a first step in using the method to calculate properties of simple polyatomic molecules. Recent high-resolution observations of both line positions and intensities have been incorporated into the method to yield new
NASA Technical Reports Server (NTRS)
Willsky, A. S.
1976-01-01
A number of current research directions in the fields of digital signal processing and modern control and estimation theory were studied. Topics such as stability theory, linear prediction and parameter identification, system analysis and implementation, two-dimensional filtering, decentralized control and estimation, image processing, and nonlinear system theory were examined in order to uncover some of the basic similarities and differences in the goals, techniques, and philosophy of the two disciplines. An extensive bibliography is included.
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
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.
Dipanwita Ghanti; Debashish Chowdhury
2015-01-09
A microtubule (MT) is a hollow tube of approximately 25 nm diameter. The two ends of the tube are dissimilar and are designated as `plus' and `minus' ends. Motivated by the collective push and pull exerted by a bundle of MTs during chromosome segregation in a living cell, we have developed here a much simplified theoretical model of a bundle of parallel dynamic MTs. The plus-end of all the MTs in the bundle are permanently attached to a movable `wall' by a device whose detailed structure is not treated explicitly in our model. The only requirement is that the device allows polymerization and depolymerization of each MT at the plus-end. In spite of the absence of external force and direct lateral interactions between the MTs, the group of polymerizing MTs attached to the wall create a load force against the group of depolymerizing MTs and vice-versa; the load against a group is shared equally by the members of that group. Such indirect interactions among the MTs gives rise to the rich variety of possible states of collective dynamics that we have identified by computer simulations of the model in different parameter regimes. The bi-directional motion of the cargo, caused by the load-dependence of the polymerization kinetics, is a "proof-of-principle" that the bi-directional motion of chromosomes before cell division does not necessarily need active participation of motor proteins.
NASA Astrophysics Data System (ADS)
Zatarain-Salazar, J.; Reed, P. M.; Herman, J. D.; Giuliani, M.; Castelletti, A.
2014-12-01
Globally reservoir operations provide fundamental services to water supply, energy generation, recreation, and ecosystems. The pressures of expanding populations, climate change, and increased energy demands are motivating a significant investment in re-operationalizing existing reservoirs or defining operations for new reservoirs. Recent work has highlighted the potential benefits of exploiting recent advances in many-objective optimization and direct policy search (DPS) to aid in addressing these systems' multi-sector demand tradeoffs. This study contributes to a comprehensive diagnostic assessment of multi-objective evolutionary optimization algorithms (MOEAs) efficiency, effectiveness, reliability, and controllability when supporting DPS for the Conowingo dam in the Lower Susquehanna River Basin. The Lower Susquehanna River is an interstate water body that has been subject to intensive water management efforts due to the system's competing demands from urban water supply, atomic power plant cooling, hydropower production, and federally regulated environmental flows. Seven benchmark and state-of-the-art MOEAs are tested on deterministic and stochastic instances of the Susquehanna test case. In the deterministic formulation, the operating objectives are evaluated over the historical realization of the hydroclimatic variables (i.e., inflows and evaporation rates). In the stochastic formulation, the same objectives are instead evaluated over an ensemble of stochastic inflows and evaporation rates realizations. The algorithms are evaluated in their ability to support DPS in discovering reservoir operations that compose the tradeoffs for six multi-sector performance objectives with thirty-two decision variables. Our diagnostic results highlight that many-objective DPS is very challenging for modern MOEAs and that epsilon dominance is critical for attaining high levels of performance. Epsilon dominance algorithms epsilon-MOEA, epsilon-NSGAII and the auto adaptive Borg MOEA, are statistically superior for the six-objective Susquehanna instance of this important class of problems. Additionally, shifting from deterministic history-based DPS to stochastic DPS significantly increases the difficulty of the problem.
A. Gütlein; G. Angloher; A. Bento; C. Bucci; L. Canonica; A. Erb; F. v. Feilitzsch; N. Ferreiro Iachellini; P. Gorla; D. Hauff; J. Jochum; M. Kiefer; H. Kluck; H. Kraus; J. -C. Lanfranchi; J. Loebell; A. Münster; F. Petricca; W. Potzel; F. Pröbst; F. Reindl; S. Roth; K. Rottler; C. Sailer; K. Schäffner; J. Schieck; S. Schönert; W. Seidel; M. v. Sivers; L. Stodolsky; C. Strandhagen; R. Strauss; A. Tanzke; M. Uffinger; A. Ulrich; I. Usherov; S. Wawoczny; M. Willers; M. Wüstrich; A. Zöller
2015-03-17
Atmospheric and solar neutrinos scattering coherently off target nuclei will be an important background source for the next generation of direct dark matter searches. In this work we focus on calcium tungstate as target material. For comparison with existing works we calculate the neutrino floor indicating which sensitivities can be reached before the neutrino background appears. In addition, we investigate the sensitivities of future direct dark matter searches using CRESST-II like detectors. Extending previous works we take into account achievable energy resolutions and thresholds as well as beta and gamma backgrounds for this investigation. We show that an exploration of WIMP-nucleon cross sections below the neutrino floor is possible for exposures of $\\gtrsim10$ kg-years or higher. In the third part we show that a first detection of coherent neutrino nucleus scattering of atmospheric and solar neutrinos using the same detectors and the backgrounds is feasible for exposures of $\\gtrsim50$ kg-years.
Gao, Fei [Pacific Northwest National Laboratory (PNNL); Heinisch, Howard [Pacific Northwest National Laboratory (PNNL); Kurtz, Richard [Pacific Northwest National Laboratory (PNNL); Osetskiy, Yury N [ORNL; Hoagland, R.G. [Pacific Northwest National Laboratory (PNNL)
2005-01-01
The interstitial clusters produced by cascades in metals have very high mobility and exhibit thermally activated, one-dimensional glide along <1 1 1> directions. Only small interstitial clusters (<4) are observed to change their glide direction during the period of molecular dynamics (MD) simulations ({approx}10 ns), but the directional change for larger clusters is inaccessible to MD due to the limited time-scale. In order to overcome the 'time barrier' in MD simulations, the dimer method is employed to search for possible transition states of interstitials and small interstitial clusters in {alpha}-Fe. The method uses only the first derivatives of the potential energy to find saddle points without knowledge of the final state of the transition. The possible transition states are studied as a function of interstitial cluster size, and the lowest energy barriers correspond to defect migration along <1 1 1> directions, as seen in MD simulations. Small clusters change their direction by a <1 1 0> fragment mechanism involving rotation of each crowdion into and out of the <1 1 0> dumbbell configuration, whereas the directional change for larger clusters is a two-step process consisting of translation along a <1 0 0> direction and rotation into an equivalent <1 1 1> direction. The mechanism of changing direction for a tri-interstitial cluster is also investigated using MD simulations.
Gao, Fei; Heinisch, Howard L.; Kurtz, Richard J.; Osetsky, Yuri N.; Hoagland, Richard G.
2005-02-01
The interstitial clusters produced by cascades in metals have very high mobility and exhibit thermally activated, one-dimensional glide along the crowdion direction, as revealed by molecular dynamics (MD) simulations. Only small interstitial clusters (<4) are observed to change their glide direction during the period of MD simulations ({approx} 10 ns), but the directional change for larger clusters is inaccessible to MD due to the limited time-scale. In order to overcome the ''time barrier'' in MD simulations, the dimer method is employed to search for possible transition states of interstitials and small interstitial clusters in alpha-Fe. The method uses only the first derivatives of the potential energy to find saddle points without knowledge of the final state of the transition. The possible transition states are studied as a function of interstitial cluster size, and the lowest energy barriers correspond to defect migration along (111) directions, as seen in MD simulations. Small clusters change their direction by a (110) fragment mechanism involving rotation of each crowdion into and out of the (110) dumbbell configuration, whereas the directional change for larger clusters is a two-step process consisting of translation along a <100> direction and rotation into an equivalent (111) direction. The mechanism of changing direction for a tri-interstitial cluster is also investigated using MD simulations.
Dietmar Wolfram; Alexandra Dimitroff
1998-01-01
The purpose of this study is to carry out a direct comparison of a hypertext-based bibliographic retrieval system with a traditional Boolean-based retrieval system, each using the same database. Novice and experienced searchers were assigned to either a prototype hypertext system called HyperLynx or to a traditional Boolean system and were asked to perform a set of search tasks. The
PARALLEL DATABASE MACHINES Kjell Bratbergsengen
and database servers for "new" data types, notably film and video. THE TRAUMATIC HISTORY OF DATABASE COMPUTERS and later, European Community supported developments. Also the massively parallel search system based
Parallel Bifold: Large-Scale Parallel Pattern Mining with Constraints
Zaiane, Osmar R.
Parallel Bifold: Large-Scale Parallel Pattern Mining with Constraints Mohammad El-Hajj, Osmar R. Za size; not only the extent of the existing patterns, but mainly the magnitude of the search space. Many cost between $50 and $100. While discovering hidden knowledge in the available repositories of data
NASA Astrophysics Data System (ADS)
Koshida, N.; Kojima, A.; Ikegami, N.; Suda, R.; Yagi, M.; Shirakashi, J.; Yoshida, T.; Miyaguchi, H.; Muroyama, M.; Nishino, H.; Yoshida, S.; Sugata, M.; Totsu, K.; Esashi, M.
2015-03-01
Making the best use of the characteristic features in nanocrystalline Si (nc-Si) ballistic hot electron source, the alternative lithographic technology is presented based on the two approaches: physical excitation in vacuum and chemical reduction in solutions. The nc-Si cold cathode is a kind of metal-insulator-semiconductor (MIS) diode, composed of a thin metal film, an nc-Si layer, an n+-Si substrate, and an ohmic back contact. Under a biased condition, energetic electrons are uniformly and directionally emitted through the thin surface electrodes. In vacuum, this emitter is available for active-matrix drive massive parallel lithography. Arrayed 100×100 emitters (each size: 10×10 ?m2, pitch: 100 ?m) are fabricated on silicon substrate by conventional planar process, and then every emitter is bonded with integrated complementary metal-oxide-semiconductor (CMOS) driver using through-silicon-via (TSV) interconnect technology. Electron multi-beams emitted from selected devices are focused by a micro-electro-mechanical system (MEMS) condenser lens array and introduced into an accelerating system with a demagnification factor of 100. The electron accelerating voltage is 5 kV. The designed size of each beam landing on the target is 10×10 nm2 in square. Here we discuss the fabrication process of the emitter array with TSV holes, implementation of integrated ctive-matrix driver circuit, the bonding of these components, the construction of electron optics, and the overall operation in the exposure system including the correction of possible aberrations. The experimental results of this mask-less parallel pattern transfer are shown in terms of simple 1:1 projection and parallel lithography under an active-matrix drive scheme. Another application is the use of this emitter as an active electrode supplying highly reducing electrons into solutions. A very small amount of metal-salt solutions is dripped onto the nc-Si emitter surface, and the emitter is driven without using any counter electrodes. After the emitter operation, thin metal (Cu, Ni, Co, and so on) and elemental semiconductors (Si and Ge) films are uniformly deposited on the emitting surface. Spectroscopic surface and compositional analyses indicate that there are no significant contaminations in deposited thin films. The implication is that ballistic hot electrons injected into solutions with appropriate kinetic energies induce preferential reduction of positive ions in solutions with no by-products followed by atom migration, nuclei formation, and the subsequent thin film growth. The availability of this technique for depositing thin SiGe films is also demonstrated by using a mixture solution. When patterned fine emission windows are formed on the emitter surface, metal and semiconductor wires array are directly deposited in parallel.
Predicting Performance of Parallel Computations
Victor Wing-kit Mak; Stephen F. Lundstrom
1990-01-01
An accurate and computationally efficient method for predicting the performance of a class of parallel computations running on concurrent systems is described. A parallel computation is modeled as a task system with precedence relationships expressed as a series-parallel directed acyclic graph. Resources in a concurrent system are modeled as service centers in a queuing network model. Using these two models
Global steering of single gimballed control moment gyroscopes using a directed search
Joseph A. Paradiso
1992-01-01
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
NASA Technical Reports Server (NTRS)
Combi, Michael R.
2004-01-01
In order to understand the global structure, dynamics, and physical and chemical processes occurring in the upper atmospheres, exospheres, and ionospheres of the Earth, the other planets, comets and planetary satellites and their interactions with their outer particles and fields environs, it is often necessary to address the fundamentally non-equilibrium aspects of the physical environment. These are regions where complex chemistry, energetics, and electromagnetic field influences are important. Traditional approaches are based largely on hydrodynamic or magnetohydrodynamic (MHD) formulations and are very important and highly useful. However, these methods often have limitations in rarefied physical regimes where the molecular collision rates and ion gyrofrequencies are small and where interactions with ionospheres and upper neutral atmospheres are important. At the University of Michigan we have an established base of experience and expertise in numerical simulations based on particle codes which address these physical regimes. The Principal Investigator, Dr. Michael Combi, has over 20 years of experience in the development of particle-kinetic and hybrid kinetichydrodynamics models and their direct use in data analysis. He has also worked in ground-based and space-based remote observational work and on spacecraft instrument teams. His research has involved studies of cometary atmospheres and ionospheres and their interaction with the solar wind, the neutral gas clouds escaping from Jupiter s moon Io, the interaction of the atmospheres/ionospheres of Io and Europa with Jupiter s corotating magnetosphere, as well as Earth s ionosphere. This report describes our progress during the year. The contained in section 2 of this report will serve as the basis of a paper describing the method and its application to the cometary coma that will be continued under a research and analysis grant that supports various applications of theoretical comet models to understanding the inner comae of comets (grant NAGS- 13239 from the Planetary Atmospheres program).
Grazia, Todd J.; Plenter, Robert J.; Weber, Sarah M.; Lepper, Helen M.; Victorino, Francisco; Zamora, Martin R.; Pietra, Biagio A.; Gill, Ronald G.
2009-01-01
Background CD4 T cells can suffice as effector cells to mediate primary acute cardiac allograft rejection. While CD4 T cells can readily kill appropriate target cells in vitro, the corresponding role of such cytolytic activity for mediating allograft rejection in vivo is unknown. Therefore, we determined whether the cytolytic effector molecules perforin and/or FasL (CD95L) were necessary for CD4 T cell-mediated rejection in vivo. Methods Wild type C3H(H-2k) or Fas (CD95)-deficient C3Hlpr (H-2k) hearts were transplanted into immune-deficient C57B6rag?/? (H-2b) mice. Recipients then were reconstituted with naïve purified CD4 T cells from either wild-type, perforin (pfp)-deficient, or FasL (gld)-deficient T cell donors. Results In vitro, alloreactive CD4 T cells were competent to lyse donor MHC class II+ target cells, largely by a Fas-dependent mechanism. In vivo, the individual disruption of either donor Fas expression (lpr) or CD4 T cell-derived perforin had no signifcant impact on acute rejection. However, FasL-deficient (gld) CD4 T cells demonstrated delayed allograft rejection. Importantly, the simultaneous removal of both donor Fas expression and CD4 T cell perforin completely abrograted acute rejection, despite the persistence of CD4 T cells within the graft. Conclusions Results demonstrate that the direct rejection of cardiac allografts by CD4 effector T cells requires the alternative contribution of graft Fas expression and T cell perforin expression. To our knowledge, this is the first demonstration that cytolytic activity by CD4 T cells can play an obligate role for primary acute allograft rejection in vivo. PMID:20061916
Reyes, Juan C.; Kalkan, Erol
2012-01-01
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.
Wavefront Synthesis and Reconstruction: Direct Binary Search Holograms and Synthetic Aperture Radar.
NASA Astrophysics Data System (ADS)
Jennison, Brian Keith
Computer-generated binary holograms can perform complex waveshaping functions that are beyond the capability of ordinary refractive optical elements. An iterative procedure for the synthesis of computer-generated holograms (CGH's) is investigated that consists of a direct binary search (DBS) for the element configuration that minimizes the error between the actual and desired reconstructed wavefronts. Although DBS CGH's have low reconstruction error and high diffraction efficiency, images reconstructed from DBS holograms suffer from leakage noise due to parts of the diffraction pattern that are not controlled by the algorithm. The statistics of the nonhomogeneous leakage noise are analyzed under the assumption of independent, identically-distributed addressable hologram cell transmittances. The severity of the leakage noise is compared to the representation -related error caused by the finite resolution and binary transmittance of the medium used to realize the CGH. Except for a cross artifact due to a nonzero mean hologram transmittance, the leakage is found to exhibit speckle-like unity contrast. Due to the computational complexity of the DBS algorithm, it has been limited to synthesis of CGH's with a relatively small number of addressable cells. To ameliorate this disadvantage, a fast algorithm is developed that recursively computes the error measure to be minimized. For complex amplitude-based error, the required computation for an L point CGH is reduced by a factor of sqrt{L/log_2/L}. The fast intensity-based algorithm is substantially more complicated; and modifications are considered to make the algorithm more efficient. An acceleration technique that attempts increase the rate of convergence of DBS is also investigated. Spotlight-mode synthetic aperture radar provides measurements in a limited annular sector of the two-dimensional spatial Fourier transform of the complex reflectance function of a spatially limited terrain patch. A maximum likelihood estimate of the reflectance magnitude based on the measured data is derived under the assumption of independent, uniformly distributed reflectance phase. The expectation-maximization (EM) algorithm is employed to solve the nonlinear likelihood function; and it yields a computationally efficient iterative estimator.
George E. Higgins; Gennaro F. Vito; William F. Walsh
2008-01-01
Racial profiling is an important issue in contemporary policing. Racial profiling research has primarily involved two things: (1) examining traffic stop data, and (2) using a benchmark or baseline in the discovery of racial profiling. A smaller literature has examined the searches to uncover racial profiling. The purpose of the present study is to examine traffic stop data-in particular searches-in
RSCS: A Parallel Simplex Algorithm for the Nimrod\\/O Optimization Toolset
Andrew Lewis; David Abramson; Tom Peachey
2004-01-01
This paper describes a method of parallelisation of the popular Nelder-Mead simplex optimization algorithms that can lead to enhanced performance on parallel and distributed computing resources. A reducing set of simplex vertices are used to derive search directions generally closely aligned with the local gradient. When tested on a range of problems drawn from real- world applications in science and
Harborth, J; Weber, K; Osborn, M
1995-01-01
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 PMID:7781599
Jonker, Willem; Lamoree, Marja H; Houtman, Corine J; Hamers, Timo; Somsen, Govert W; Kool, Jeroen
2015-08-01
In this study we developed a new LC nanofractionation platform that combines a human cell (BG1.Luc) gene reporter assay with a high resolution mass spectrometer for the detection and identification of estrogenic and anti-estrogenic compounds in environmental waters. The selection of this assay was based on its high sensitivity and selectivity, which is required for environmental trace level detection. We modified an autosampler and controlled it with in-house developed software to collect fractions in the low second range in microtiter plates. This ensured that chromatographic separation was maintained and allowed straightforward hyphenation with the bioassay. After bioassay testing, bioassay chromatograms were reconstructed and directly correlated with MS chromatograms that were obtained in parallel. This enabled to pinpoint bioactives in the MS chromatogram within a single fractionation cycle and results in a significant increase in throughput compared to traditional EDA studies. The sensitivity of the platform was low enough for environmental waters (80nM for bisphenol A and 320pM and 3.2nM for estradiol and estriol, respectively). In addition, the ability of the platform to detect anti-estrogens was successfully demonstrated as well. Finally, real samples were analysed. PMID:26116188
Etienne, Loïc; Rousset, François; Godelle, Bernard; Courtiol, Alexandre
2014-01-01
Most theoretical research in sexual selection has focused on indirect selection. However, empirical studies have not strongly supported indirect selection. A well-established finding is that direct benefits and costs exert a strong influence on the evolution of mate choice. We present an analytical model in which unilateral mate choice evolves solely by direct sexual selection on choosiness. We show this is sufficient to generate the evolution of all possible levels of choosiness, because of the fundamental trade-off between mating rate and mating benefits. We further identify the relative searching time (RST, i.e. the proportion of lifetime devoted to searching for mates) as a predictor of the effect of any variable affecting the mating rate on the evolution of choosiness. We show that the RST: (i) allows one to make predictions about the evolution of choosiness across a wide variety of mating systems; (ii) encompasses all alternative variables proposed thus far to explain the evolution of choosiness by direct sexual selection; and (iii) can be empirically used to infer qualitative differences in choosiness. PMID:24789896
Lambert, Sylvie D; Girgis, Afaf; McElduff, Patrick; Turner, Jane; Levesque, Janelle V; Kayser, Karen; Mihalopoulos, Cathrine; Shih, Sophy T F; Barker, Daniel
2013-01-01
Introduction Coping skills training interventions have been found to be efficacious in helping both patients and their partners manage the physical and emotional challenges they face following a cancer diagnosis. However, many of these interventions are costly and not sustainable. To overcome these issues, a self-directed format is increasingly used. The efficacy of self-directed interventions for patients has been supported; however, no study has reported on the outcomes for their partners. This study will test the efficacy of Coping-Together—a multimedia, self-directed, coping skills training intervention for patients with cancer and their partners. Methods and analysis The proposed three-group, parallel, randomised controlled trial will recruit patients diagnosed in the past 4?months with breast, prostate, colorectal cancer or melanoma through their treating clinician. Patients and their partners will be randomised to (1) a minimal ethical care (MEC) condition—selected Cancer Council New South Wales booklets and a brochure for the Cancer Council Helpline, (2) Coping-Together generic—MEC materials, the six Coping-Together booklets and DVD, the Cancer Council Queensland relaxation audio CD and login to the Coping-Together website or (3) Coping-Together tailored—MEC materials, the Coping-Together DVD, the login to the website and only those Coping-Together booklet sections that pertain to their direct concerns. Anxiety (primary outcome), distress, depression, dyadic adjustment, quality of life, illness or caregiving appraisal, self-efficacy and dyadic and individual coping will be assessed before receiving the study material (ie, baseline) and again at 3, 6 and 12?months postbaseline. Intention-to-treat and per protocol analysis will be conducted. Ethics and dissemination This study has been approved by the relevant local area health and University ethics committees. Study findings will be disseminated not only through peer-reviewed publications and conference presentations but also through educational outreach visits, publication of lay research summaries in consumer newsletters and publications targeting clinicians. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12613000491763 (03/05/2013) PMID:23883890
Direct search for solar axions by using strong magnetic field and X-ray detectors
Shigetaka Moriyama; Makoto Minowa; Toshio Namba; Yoshizumi Inoue; Yuko Takasu; Akira Yamamoto
1998-01-01
We have searched for axions which could be produced in the solar core by exploiting their conversion to X rays in a strong laboratory magnetic field. The signature of the solar axion is an increase in the rate of the X rays detected in a magnetic helioscope when the sun is within its acceptance.From the absence of such a signal
Leportier, Thibault; Park, Min Chul; Kim, You Seok; Kim, Taegeun
2015-02-01
In this paper, we present a three-dimensional holographic imaging system. The proposed approach records a complex hologram of a real object using optical scanning holography, converts the complex form to binary data, and then reconstructs the recorded hologram using a spatial light modulator (SLM). The conversion from the recorded hologram to a binary hologram is achieved using a direct binary search algorithm. We present experimental results that verify the efficacy of our approach. To the best of our knowledge, this is the first time that a hologram of a real object has been reconstructed using a binary SLM. PMID:25836197
S. Burgos; E. Daw; J. Forbes; C. Ghag; M. Gold; C. Hagemann; V. A. Kudryavtsev; T. B. Lawson; D. Loomba; P. Majewski; D. Muna; A. StJ. Murphy; G. G. Nicklin; S. M. Paling; A. Petkov; S. J. S. Plank; M. Robinson; N. Sanghi; D. P. Snowden-Ifft; N. J. C. Spooner; J. Turk; E. Tziaferi
2008-09-10
We present first evidence for the so-called Head-Tail asymmetry signature of neutron-induced nuclear recoil tracks at energies down to 1.5 keV/amu using the 1m^3 DRIFT-IIc dark matter detector. This regime is appropriate for recoils induced by Weakly Interacting Massive Particle (WIMPs) but one where the differential ionization is poorly understood. We show that the distribution of recoil energies and directions induced here by Cf-252 neutrons matches well that expected from massive WIMPs. The results open a powerful new means of searching for a galactic signature from WIMPs.
Wang, Wenyi; Wu, Renbiao
2013-01-01
DOA (Direction of Arrival) estimation is a major problem in array signal processing applications. Recently, compressive sensing algorithms, including convex relaxation algorithms and greedy algorithms, have been recognized as a kind of novel DOA estimation algorithm. However, the success of these algorithms is limited by the RIP (Restricted Isometry Property) condition or the mutual coherence of measurement matrix. In the DOA estimation problem, the columns of measurement matrix are steering vectors corresponding to different DOAs. Thus, it violates the mutual coherence condition. The situation gets worse when there are two sources from two adjacent DOAs. In this paper, an algorithm based on OMP (Orthogonal Matching Pursuit), called ILS-OMP (Iterative Local Searching-Orthogonal Matching Pursuit), is proposed to improve DOA resolution by Iterative Local Searching. Firstly, the conventional OMP algorithm is used to obtain initial estimated DOAs. Then, in each iteration, a local searching process for every estimated DOA is utilized to find a new DOA in a given DOA set to further decrease the residual. Additionally, the estimated DOAs are updated by substituting the initial DOA with the new one. The simulation results demonstrate the advantages of the proposed algorithm. PMID:23974150
Wang, Wenyi; Wu, Renbiao
2013-01-01
DOA (Direction of Arrival) estimation is a major problem in array signal processing applications. Recently, compressive sensing algorithms, including convex relaxation algorithms and greedy algorithms, have been recognized as a kind of novel DOA estimation algorithm. However, the success of these algorithms is limited by the RIP (Restricted Isometry Property) condition or the mutual coherence of measurement matrix. In the DOA estimation problem, the columns of measurement matrix are steering vectors corresponding to different DOAs. Thus, it violates the mutual coherence condition. The situation gets worse when there are two sources from two adjacent DOAs. In this paper, an algorithm based on OMP (Orthogonal Matching Pursuit), called ILS-OMP (Iterative Local Searching-Orthogonal Matching Pursuit), is proposed to improve DOA resolution by Iterative Local Searching. Firstly, the conventional OMP algorithm is used to obtain initial estimated DOAs. Then, in each iteration, a local searching process for every estimated DOA is utilized to find a new DOA in a given DOA set to further decrease the residual. Additionally, the estimated DOAs are updated by substituting the initial DOA with the new one. The simulation results demonstrate the advantages of the proposed algorithm. PMID:23974150
Footprint of Triplet Scalar Dark Matter in Direct, Indirect Search and Invisible Higgs Decay
Seyed Yaser Ayazi; S. Mahdi Firouzabadi
2015-01-25
In this talk, we will review Inert Triplet Model (ITM) which provide candidate for dark matter (DM) particles. Then we study possible decays of Higgs boson to DM candidate and apply current experimental data for invisible Higgs decay to constrain parameter space of ITM. We also consider indirect search for DM and use FermiLAT data to put constraints on parameter space. Ultimately we compare this limit with constraints provided by LUX experiment for low mass DM and invisible Higgs decay.
NASA Astrophysics Data System (ADS)
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
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.
Heon-Young Chang
2001-07-17
We study the power density spectrum (PDS) of light curves of the observed gamma-ray bursts (GRBs) to search for a direct signature for cosmological time dilation in the PDS statistics with the GRBs whose redshifts $z$'s are known. The anticorrelation of a timescale measure and a brightness measure is indirect evidence of its effect. On the other hand, we directly demonstrate that a time dilation effect can be seen in GRB light curves. We find that timescales tend to be shorter in bursts with small redshift, as expected from cosmological time-dilation effects, and we also find that there may be non-cosmological effects constituting to this correlation. We discuss its implication on interpretations of the PDS analysis results. We put forward another caution to this kind of analysis when we statistically exercise with GRBs whose $z$ is unknown.
Automatic Multilevel Parallelization Using OpenMP
NASA Technical Reports Server (NTRS)
Jin, Hao-Qiang; Jost, Gabriele; Yan, Jerry; Ayguade, Eduard; Gonzalez, Marc; Martorell, Xavier; Biegel, Bryan (Technical Monitor)
2002-01-01
In this paper we describe the extension of the CAPO (CAPtools (Computer Aided Parallelization Toolkit) OpenMP) parallelization support tool to support multilevel parallelism based on OpenMP directives. CAPO generates OpenMP directives with extensions supported by the NanosCompiler to allow for directive nesting and definition of thread groups. We report some results for several benchmark codes and one full application that have been parallelized using our system.
Direct search for pair production of heavy stable charged particles in Z decays
Soderstrom, E.; McKenna, J.A.; Abrams, G.S.; Adolphsen, C.E.; Averill, D.; Ballam, J.; Barish, B.C.; Barklow, T.; Barnett, B.A.; Bartelt, J.; Bethke, S.; Blockus, D.; Bonvicini, G.; Boyarski, A.; Brabson, B.; Breakstone, A.; Bulos, F.; Burchat, P.R.; Burke, D.L.; Cence, R.J.; Chapman, J.; Chmeissani, M.; Cords, D.; Coupal, D.P.; Dauncey, P.; DeStaebler, H.C.; Dorfan, D.E.; Dorfan, J.M.; Drewer, D.C.; Elia, R.; Feldman, G.J.; Fernandes, D.; Field, R.C.; Ford, W.T.; Fordham, C.; Frey, R.; Fujino, D.; Gan, K.K.; Gero, E.; Gidal, G.; Glanzman, T.; Goldhaber, G.; Gomez Cadenas, J.J.; Gratta, G.; Grindhammer, G.; Grosse-Wiesmann, P.; Hanson, G.; Harr, R.; Harral, B.; Harris, F.A.; Hawkes, C.M.; Hayes, K.; Hearty, C.; Heusch, C.A.; Hildreth, M.D.; Himel, T.; Hinshaw, D.A.; Hong, S.J.; Hutchinson, D.; Hylen, J.; Innes, W.R.; Jacobsen, R.G.; Jaros, J.A.; Jung, C.K.; Kadyk, J.A.; Kent, J.; King, M.; Koetke, D.S.; Komamiya, S.; Koska, W.; Kowalski, L.A.; Kozanecki, W.; Kral, J.F.; Kuhlen, M.; Lab
1990-06-18
A search for pair production of stable charged particles from {ital Z} decay has been performed with the Mark II detector at the SLAC Linear Collider. Particle masses are determined from momentum, ionization energy loss, and time-of-flight measurements. A limit excluding pair production of stable fourth-generation charged leptons and stable mirror fermions with masses between the muon mass and 36.3 GeV/{ital c}{sup 2} is set at the 95% confidence level. Pair production of stable supersymmetric scalar leptons with masses between the muon mass and 32.6 GeV/{ital c}{sup 2} is also excluded.
Direct Search for Mass of Neutrino and Anomaly in the Tritium Beta-Spectrum
NASA Astrophysics Data System (ADS)
Lobashev, V. M.; Aseev, V. N.; Belesev, A. I.; Berlev, A. I.; Geraskin, E. V.; Golubev, A. A.; Kazachenko, O. V.; Kuznetsov, Yu. E.; Ostroumov, R. P.; Rivkis, L. A.; Stern, B. E.; Titov, N. A.; Zadoroghny, C. V.; Zakharov, Yu. I.
2000-06-01
Results of the "Troitsk ?-mass" experiment on the search for the neutrino rest mass in the tritium beta-decay are presented. Study of time dependence of anomalious, bump-like structure at the end of beta spectrum reported earlier gives indication of periodic shift of the position of the bump with respect to end-point energy with period of 0.5 year. New upper limit for electron antineutrino rest mass m ?< 2.5 {eV}/{c2} is derived after accounting for the bump.
Equivalency-processing parallel photonic integrated circuit EP3
Louri, Ahmed
Equivalency-processing parallel photonic integrated circuit EP3 IC : equivalence search module present an optoelectronic module called the equivalency-processing parallel photonic integrated circuit EP.e., database word searches . The module combines a parallel-computation model with multiwavelength photonic
Searching for evidence of a preferred rupture direction in small earthquakes at Parkfield
NASA Astrophysics Data System (ADS)
Kane, D. L.; Shearer, P. M.; Allmann, B.; Vernon, F. L.
2009-12-01
Theoretical modeling of strike-slip ruptures along a bimaterial interface suggests that the interface will have a preferred rupture direction and will produce asymmetric ground motion (Shi and Ben-Zion, 2006). This could have widespread implications for earthquake source physics and for hazard analysis on mature faults because larger ground motions would be expected in the direction of rupture propagation. Studies have shown that many large global earthquakes exhibit unilateral rupture, but a consistently preferred rupture direction along faults has not been observed. Some researchers have argued that the bimaterial interface model does not apply to natural faults, noting that the rupture of the M 6 2004 Parkfield earthquake propagated in the opposite direction from previous M 6 earthquakes along that section of the San Andreas Fault (Harris and Day, 2005). We analyze earthquake spectra from the Parkfield area to look for evidence of consistent rupture directivity along the San Andreas Fault. We separate the earthquakes into spatially defined clusters and quantify the differences in high-frequency energy among earthquakes recorded at each station. Propagation path effects are minimized in this analysis because we compare earthquakes located within a small volume and recorded by the same stations. By considering a number of potential end-member models, we seek to determine if a preferred rupture direction is present among small earthquakes at Parkfield.
Jean-marc Jézéquel; Jean-lin Pacherie
1996-01-01
: Encapsulating parallelism and synchronization code within object-oriented softwarecomponents is a promising avenue towards mastering the complexity of the distributedmemory supercomputer programming. However, in trying to give application programmersbenefit of supercomputer power, the library designer generally resorts to low level parallelconstructs, a time consuming and error prone process. To solve this problem we introducea new abstraction called Parallel Operators. A
A Framework for Quantum Search Heuristics
Tad Hogg
1996-11-04
A quantum algorithm for combinatorial search is presented that provides a simple framework for utilizing search heuristics. The algorithm is evaluated in a new case that is an unstructured version of the graph coloring problem. It performs significantly better than the direct use of quantum parallelism, on average, in cases corresponding to previously identified phase transitions in search difficulty. The conditions underlying this improvement are described. Much of the algorithm is independent of particular problem instances, making it suitable for implementation as a special purpose device.
NSDL National Science Digital Library
An introduction to optimisation techniques that may improve parallel performance and scaling on HECToR. It assumes that the reader has some experience of parallel programming including basic MPI and OpenMP. Scaling is a measurement of the ability for a parallel code to use increasing numbers of cores efficiently. A scalable application is one that, when the number of processors is increased, performs better by a factor which justifies the additional resource employed. Making a parallel application scale to many thousands of processes requires not only careful attention to the communication, data and work distribution but also to the choice of the algorithms to use. Since the choice of algorithm is too broad a subject and very particular to application domain to include in this brief guide we concentrate on general good practices towards parallel optimisation on HECToR.
NASA Astrophysics Data System (ADS)
Adrián-Martínez, S.; Samarai, I. Al; Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Astraatmadja, T.; Aubert, J.-J.; Baret, B.; Basa, S.; Beemster, L. J.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bogazzi, C.; Bou-Cabo, M.; Bouhou, B.; Bouwhuis, M. C.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Cârloganu, C.; Carminati, G.; Carr, J.; Cecchini, S.; Charif, Z.; Charvis, Ph.; Chiarusi, T.; Circella, M.; Coniglione, R.; Core, L.; Costantini, H.; Coyle, P.; Creusot, A.; Curtil, C.; De Bonis, G.; Decowski, M. P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti, Q.; Drouhin, D.; Eberl, T.; Emanuele, U.; Enzenhöfer, A.; Ernenwein, J.-P.; Escoffier, S.; Fehn, K.; Fermani, P.; Ferri, M.; Ferry, S.; Flaminio, V.; Folger, F.; Fritsch, U.; Fuda, J.-L.; Galatà, S.; Gay, P.; Geyer, K.; Giacomelli, G.; Giordano, V.; Gómez-González, J. P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Hartman, J.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Herold, B.; Hößl, J.; Hsu, C. C.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Katz, U.; Kavatsyuk, O.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lambard, G.; Larosa, G.; Lattuada, D.; Lefèvre, D.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martínez-Mora, J. A.; Meli, A.; Montaruli, T.; Morganti, N.; Moscoso, L.; Motz, H.; Neff, M.; Nezri, E.; Palioselitis, D.; P?v?la?, G. E.; Payet, K.; Payre, P.; Petrovic, J.; Picot-Clemente, N.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Reed, C.; Riccobene, G.; Richardt, C.; Richter, R.; Rivière, C.; Robert, A.; Roensch, K.; Rostovtsev, A.; Ruiz-Rivas, J.; Rujoiu, M.; Russo, G. V.; Salesa, F.; Samtleben, D. F. E.; Sánchez-Losa, A.; Sapienza, P.; Schöck, F.; Schuller, J.-P.; Schüssler, F.; Seitz, T.; Shanidze, R.; Simeone, F.; Spies, A.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Taiuti, M.; Tamburini, C.; Toscano, S.; Vallage, B.; Vallée, C.; Van Elewyck, V.; Vannoni, G.; Vecchi, M.; Vernin, P.; Visser, E.; Wagner, S.; Wijnker, G.; Wilms, J.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J. D.; Zúñiga, J.
2013-09-01
A multimessenger analysis optimized for a correlation of arrival directions of ultra-high energy cosmic rays (UHECRs) and neutrinos is presented and applied to 2190 neutrino candidate events detected in 2007-2008 by the ANTARES telescope and 69 UHECRs observed by the Pierre Auger Observatory between 2004 January 1 and 2009 December 31. No significant correlation is observed. Assuming an equal neutrino flux (E -2 energy spectrum) from all UHECR directions, a 90% CL upper limit on the neutrino flux of 5.0 × 10-8 GeV cm-2 s-1 per source is derived.
Direct Search for Spin-Dependent WIMPS with CaF2 Detector
NASA Astrophysics Data System (ADS)
Hazama, R.; Ogawa, I.; Mukaida, K.; Ajimura, S.; Hirano, Y.; Ichihara, K.; Ishikawa, Y.; Itamura, M.; Katsuki, A.; Kishimoto, K.; Matsuoka, K.; Miyawaki, H.; Nitta, T.; Sakai, H.; Shiomi, S.; Suzuki, N.; Tanaka, Y.; Tatewaki, Y.; Tomii, S.; Umehara, S.; Yokoyama, D.; Yoshida, S.; Kishimoto, T.
2008-04-01
A CaF2 scintillator complex system (ELEGANT VI) is developed to search for the axial-vector coupled dark matter (WIMPs) and study the neutrino-less double beta decay of 48Ca. Active light guides of pure CaF2 crystals which are on both sides of the central CaF2(Eu) crystal act as a 4? active shield, combined with surrounding CsI(Tl) scintillators. The whole system is in operation at the underground laboratory (Oto Cosmo Observatory) located in Nara. In this article recent several improvements and our current status of the investigation are described, especially putting emphasis on the radioactive impurities of CaF2 crystal and development of flash scaler/trigger system with FPGA (Field Programmable Gate Array) to do a single photon counting and a noise-cut via photon time distribution.
Direct imaging and new technologies to search for substellar companions around MGs cool dwarfs
NASA Astrophysics Data System (ADS)
Gálvez-Ortiz, M. C.; Clarke, J. R. A.; Pinfield, D. J.; Folkes, S. L.; Jenkins, J. S.; García Pérez, A. E.; Burningham, B.; Day-Jones, A. C.; Jones, H. R. A.
2011-07-01
We describe here our project based in a search for sub-stellar companions (brown dwarfs and exo-planets) around young ultra-cool dwarfs (UCDs) and characterise their properties. We will use current and future technology (high contrast imaging, high-precision Doppler determinations) from the ground and space (VLT, ELT and JWST), to find companions to young objects. Members of young moving groups (MGs) have clear advantages in this field. We compiled a catalogue of young UCD objects and studied their membership to five known young moving groups: Local Association (Pleiades moving group, 20-150 Myr), Ursa Mayor group (Sirius supercluster, 300 Myr), Hyades supercluster (600 Myr), IC 2391 supercluster (35 Myr) and Castor moving group (200 Myr). To assess them as members we used different kinematic and spectroscopic criteria.
ERIC Educational Resources Information Center
Weisbord, Marvin R.; And Others
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…
Paola Leaci; Reinhard Prix
2015-04-09
We derive simple analytic expressions for the (coherent and semi-coherent) phase metrics of continuous-wave sources in low-eccentricity binary systems, both for the long-segment and short- segment regimes (compared to the orbital period). The resulting expressions correct and extend previous results found in the literature. We present results of extensive Monte-Carlo studies comparing metric mismatch predictions against the measured loss of detection statistic for binary parameter offsets. The agreement is generally found to be within ~ 10%-30%. As an application of the metric template expressions, we estimate the optimal achievable sensitivity of an Einstein@Home directed search for Scorpius X-1, under the assumption of sufficiently small spin wandering. We find that such a search, using data from the upcoming advanced detectors, would be able to beat the torque- balance level [1,2] up to a frequency of ~ 500 - 600 Hz, if orbital eccentricity is well-constrained, and up to a frequency of ~ 160 - 200 Hz for more conservative assumptions about the uncertainty on orbital eccentricity.
Julien Lavalle; David Maurin; Antje Putze
2015-01-22
Galactic Cosmic-ray (CR) transport parameters are usually constrained by the boron-to-carbon ratio. This procedure is generically plagued with degeneracies between the diffusion coefficient and the vertical extent of the Galactic magnetic halo. The latter is of paramount importance for indirect dark matter (DM) searches, because it fixes the amount of DM annihilation or decay that contributes to the local antimatter CR flux. These degeneracies could be broken by using secondary radioactive species, but the current data still have large error bars, and this method is extremely sensitive to the very local interstellar medium (ISM) properties. Here, we propose to use the low-energy CR positrons in the GeV range as another direct constraint on diffusion models. We show that the PAMELA data disfavor small diffusion halo ($L\\lesssim 3$ kpc) and large diffusion slope models, and exclude the minimal ({\\em min}) configuration (Maurin et al. 2001, Donato et al. 2004) widely used in the literature to bracket the uncertainties in the DM signal predictions. This is complementary to indirect constraints (diffuse radio and gamma-ray emissions) and has strong impact on DM searches. Indeed this makes the antiproton constraints more robust while enhancing the discovery/exclusion potential of current and future experiments, like AMS-02 and GAPS, especially in the antiproton and antideuteron channels.
NASA Astrophysics Data System (ADS)
Kozlov, Valentin; EDELWEISS Collaboration
2013-08-01
Due to a very low event rate expected in direct dark matter search experiments, a good understanding of every background component is crucial. Muon-induced neutrons constitute a prominent background, since neutrons lead to nuclear recoils and thus can mimic a potential dark matter signal. EDELWEISS is a Ge-bolometer experiment searching for WIMP dark matter. It is located in the Laboratoire Souterrain de Modane (LSM, France). We have measured muon-induced neutrons by means of a neutron counter based on Gd-loaded liquid scintillator. Studies of muon-induced neutrons are presented and include development of the appropriate MC model based on Geant4 and analysis of a 1000-days measurement campaign in LSM. We find a good agreement between measured rates of muon-induced neutrons and those predicted by the developed model with full event topology. The impact of the neutron background on current EDELWEISS data-taking as well as for next generation experiments such as EURECA is briefly discussed.
Kozlov, Valentin [Karlsruhe Institute of Technology, Institut für Kernphysik, Postfach 3640, 76021 Karlsruhe (Germany)] [Karlsruhe Institute of Technology, Institut für Kernphysik, Postfach 3640, 76021 Karlsruhe (Germany); Collaboration: EDELWEISS Collaboration
2013-08-08
Due to a very low event rate expected in direct dark matter search experiments, a good understanding of every background component is crucial. Muon-induced neutrons constitute a prominent background, since neutrons lead to nuclear recoils and thus can mimic a potential dark matter signal. EDELWEISS is a Ge-bolometer experiment searching for WIMP dark matter. It is located in the Laboratoire Souterrain de Modane (LSM, France). We have measured muon-induced neutrons by means of a neutron counter based on Gd-loaded liquid scintillator. Studies of muon-induced neutrons are presented and include development of the appropriate MC model based on Geant4 and analysis of a 1000-days measurement campaign in LSM. We find a good agreement between measured rates of muon-induced neutrons and those predicted by the developed model with full event topology. The impact of the neutron background on current EDELWEISS data-taking as well as for next generation experiments such as EURECA is briefly discussed.
Leaci, Paola
2015-01-01
We derive simple analytic expressions for the (coherent and semi-coherent) phase metrics of continuous-wave sources in low-eccentricity binary systems, both for the long-segment and short- segment regimes (compared to the orbital period). The resulting expressions correct and extend previous results found in the literature. We present results of extensive Monte-Carlo studies comparing metric mismatch predictions against the measured loss of detection statistic for binary parameter offsets. The agreement is generally found to be within ~ 10%-30%. As an application of the metric template expressions, we estimate the optimal achievable sensitivity of an Einstein@Home directed search for Scorpius X-1, under the assumption of sufficiently small spin wandering. We find that such a search, using data from the upcoming advanced detectors, would be able to beat the torque- balance level [1,2] up to a frequency of ~ 500 - 600 Hz, if orbital eccentricity is well-constrained, and up to a frequency of ~ 160 - 200 Hz for m...
Bhattacherjee, Biplob; Choudhury, Arghya
2015-01-01
In this paper, we search for the regions of the phenomenological minimal supersymmetric standard model (pMSSM) parameter space where one can expect to have moderate Higgs mixing angle ($\\alpha$) with relatively light (up to 600 GeV) additional Higgses after satisfying the current LHC data. We perform a global fit analysis using most updated data (till December 2014) from the LHC and Tevatron experiments. The constraints coming from the precision measurements of the rare b-decays $B_s \\to \\mu^+ \\mu^-$ and $b\\to s \\gamma$ are also considered. We find that low $M_{A}$ $(\\lesssim 350)$ and high $tan\\beta$ $(\\gtrsim 25)$ regions are disfavoured by the combined effect of the global analysis and flavour data. However, regions with Higgs mixing angle $\\alpha \\sim$ 0.1 - 0.8 are still allowed by the current data. We then study the existing direct search bounds on the heavy scalar/pseudoscalar ($\\rm H/A$) and charged Higgs ($\\rm H^\\pm$) masses and branchings at the LHC. It has been found that regions with low to modera...
Armstrong, Jerawan C. [Los Alamos National Laboratory; Favorite, Jeffrey A. [Los Alamos National Laboratory
2012-06-20
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.
Quantum Computing and Phase Transitions in Combinatorial Search
Tad Hogg
1995-08-16
We introduce an algorithm for combinatorial search on quantum computers that is capable of significantly concentrating amplitude into solutions for some NP search problems, on average. This is done by exploiting the same aspects of problem structure as used by classical backtrack methods to avoid unproductive search choices. This quantum algorithm is much more likely to find solutions than the simple direct use of quantum parallelism. Furthermore, empirical evaluation on small problems shows this quantum algorithm displays the same phase transition behavior, and at the same location, as seen in many previously studied classical search methods. Specifically, difficult problem instances are concentrated near the abrupt change from underconstrained to overconstrained problems.
Shah, Ronak C.
1991-01-01
I'sge III. A Review III. B MasPar System Architecture 18 III. C MasPar FORTRAN 21 III. D MasPar Programming Environment IV MLOCFES: PARALLEL VERSION IV. A Potential Regions of Parallelism in LOCFES IV. B FORTRAN gg Adaptations IV. C Program... formulation for spherical geometry. I. C Problem Statement LOCFES is a computationally intense program written in FORTRAN 77. It exhibits some regions of fine-grained (i. e. , at the cell level) parallelism. The program and the algorithm can be modified...
Future directions in the microwave cavity search for dark matter axions
NASA Astrophysics Data System (ADS)
Shokair, T. M.; Root, J.; van Bibber, K. A.; Brubaker, B.; Gurevich, Y. V.; Cahn, S. B.; Lamoreaux, S. K.; Anil, M. A.; Lehnert, K. W.; Mitchell, B. K.; Reed, A.; Carosi, G.
2014-07-01
The axion is a light pseudoscalar particle which suppresses CP-violating effects in strong interactions and also happens to be an excellent dark matter candidate. Axions constituting the dark matter halo of our galaxy may be detected by their resonant conversion to photons in a microwave cavity permeated by a magnetic field. The current generation of the microwave cavity experiment has demonstrated sensitivity to plausible axion models, and upgrades in progress should achieve the sensitivity required for a definitive search, at least for low mass axions. However, a comprehensive strategy for scanning the entire mass range, from 1-1000 ?eV, will require significant technological advances to maintain the needed sensitivity at higher frequencies. Such advances could include sub-quantum-limited amplifiers based on squeezed vacuum states, bolometers, and/or superconducting microwave cavities. The Axion Dark Matter eXperiment at High Frequencies (ADMX-HF) represents both a pathfinder for first data in the 20-100 ?eV range ( 5-25 GHz), and an innovation test-bed for these concepts.
Porter, Joanne L; Boon, Priscilla L S; Murray, Tracy P; Huber, Thomas; Collyer, Charles A; Ollis, David L
2015-02-20
The ease with which enzymes can be adapted from their native roles and engineered to function specifically for industrial or commercial applications is crucial to enabling enzyme technology to advance beyond its current state. Directed evolution is a powerful tool for engineering enzymes with improved physical and catalytic properties and can be used to evolve enzymes where lack of structural information may thwart the use of rational design. In this study, we take the versatile and diverse ?/? hydrolase fold framework, in the form of dienelactone hydrolase, and evolve it over three unique sequential evolutions with a total of 14 rounds of screening to generate a series of enzyme variants. The native enzyme has a low level of promiscuous activity toward p-nitrophenyl acetate but almost undetectable activity toward larger p-nitrophenyl esters. Using p-nitrophenyl acetate as an evolutionary intermediate, we have generated variants with altered specificity and catalytic activity up to 3 orders of magnitude higher than the native enzyme toward the larger nonphysiological p-nitrophenyl ester substrates. Several variants also possess increased stability resulting from the multidimensional approach to screening. Crystal structure analysis and substrate docking show how the enzyme active site changes over the course of the evolutions as either a direct or an indirect result of mutations. PMID:25419863
NASA Astrophysics Data System (ADS)
Spooner, N. J. C.; Majewski, P.; Muna, D.; Snowden-Ifft, D. P.
2010-12-01
We present the first detailed simulations of the so-called head-tail effect of nuclear recoils in gas, the presence of which is vital to directional WIMP dark matter searches. We include comparison simulations of the range and straggling of carbon, sulphur and fluorine recoils in low pressure gas. However, the prime focus is a detailed investigation of carbon and sulphur recoils in 40 Torr negative ion carbon disulfide, a gas proposed for use in large scale directional detectors. The focus is to determine whether the location of the majority of the ionization charge released and observed from a recoil track in carbon disulfide is at the beginning (tail) of the track, at the end (head) or evenly distributed. We used the SRIM simulation program, together with a purpose-written Monte Carlo generator to model production of ionizing pairs, diffusion and basic readout geometries relevant to potential real detector scenarios, such as under development for the DRIFT experiment. The results indicate the likely existence of a head-tail track asymmetry but with a magnitude critically influenced by several competing factors, notably the W-value assumed, the drift distance and diffusion, and the recoil energy.
XENON1T - Direct Dark Matter Search on the Verge of a New Detector Generation
NASA Astrophysics Data System (ADS)
Aprile, Elena
2015-04-01
The XENON dark matter project aims at finding direct evidence for the scattering of weakly interacting massive dark matter particles (WIMPs) with target nuclei in an ultra-low background liquid xenon detector. After the successful operation of the XENON100 instrument - for many years the world's most sensitive deep underground WIMP detector - the next generation detector XENON1T is presently being built at the Italian Gran Sasso underground facility. The commissioning and first data taking of the experiment are expected to start in 2015. The talk will focus on the special challenges related to a ton-scale liquid xenon detector, provide a comprehensive overview of the ongoing construction phase, and discuss the prospects and projected physics reach of the experiment. We gratefully acknowledge the continuing support of the XENON dark matter project by the National Science Foundation.
Struve, Juliane; Lorenzen, Kai; Blanchard, Julia; Börger, Luca; Bunnefeld, Nils; Edwards, Charles; Hortal, Joaquín; MacCall, Alec; Matthiopoulos, Jason; Van Moorter, Bram; Ozgul, Arpat; Royer, François; Singh, Navinder; Yesson, Chris; Bernard, Rodolphe
2010-01-01
The workshop ‘Spatial models in animal ecology, management and conservation’ held at Silwood Park (UK), 9–11 March 2010, aimed to synthesize recent progress in modelling the spatial dynamics of individuals, populations and species ranges and to provide directions for research. It brought together marine and terrestrial researchers working on spatial models at different levels of organization, using empirical as well as theory-driven approaches. Different approaches, temporal and spatial scales, and practical constraints predominate at different levels of organization and in different environments. However, there are theoretical concepts and specific methods that can fruitfully be transferred across levels and systems, including: habitat suitability characterization, movement rules, and ways of estimating uncertainty. PMID:20484232
SEEK: A FORTRAN optimization program using a feasible directions gradient search
NASA Technical Reports Server (NTRS)
Savage, M.
1995-01-01
This report describes the use of computer program 'SEEK' which works in conjunction with two user-written subroutines and an input data file to perform an optimization procedure on a user's problem. The optimization method uses a modified feasible directions gradient technique. SEEK is written in ANSI standard Fortran 77, has an object size of about 46K bytes, and can be used on a personal computer running DOS. This report describes the use of the program and discusses the optimizing method. The program use is illustrated with four example problems: a bushing design, a helical coil spring design, a gear mesh design, and a two-parameter Weibull life-reliability curve fit.
Demonstrating Forces between Parallel Wires.
ERIC Educational Resources Information Center
Baker, Blane
2000-01-01
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)
Direct search for a ferromagnetic phase in a heavily overdoped nonsuperconducting copper oxide
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
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. PMID:20855579
Search for a direction in the forest of Lyman-$\\alpha$
Hazra, Dhiraj Kumar
2015-01-01
We report the first test of isotropy of the Universe in the matter dominated epoch using the Lyman-$\\alpha$ forest data from the high redshift quasars ($z>2$) from SDSS-III BOSS-DR9 datasets. Using some specified data cuts, we obtain the probability distribution function (PDF) of the Lyman-$\\alpha$ forest transmitted flux and use the statistical moments of the PDF to address the isotropy of the Universe. In an isotropic Universe one would expect the transmitted flux to have consistent statistical characteristics in different parts of the sky. We trisect the total survey area of 3275 ${\\rm deg}^2$ along the galactic latitude and using quadrant convention. We also make three subdivisions in the data for three different signal-to-noise-ratios (SNR). Finally we obtain and compare the statistical moments in the mean redshifts of 2.3, 2.6 and 2.9. We find, that the moments from all patches agree at all redshifts and at all SNRs, within 3$\\sigma$ uncertainties. Since Lyman-$\\alpha$ transmitted flux directly maps the...
Automatic Multilevel Parallelization Using OpenMP
NASA Technical Reports Server (NTRS)
Jin, Hao-Qiang; Jost, Gabriele; Yan, Jerry; Ayguade, Eduard; Gonzalez, Marc; Martorell, Xavier; Biegel, Bryan (Technical Monitor)
2002-01-01
In this paper we describe the extension of the CAPO parallelization support tool to support multilevel parallelism based on OpenMP directives. CAPO generates OpenMP directives with extensions supported by the NanosCompiler to allow for directive nesting and definition of thread groups. We report first results for several benchmark codes and one full application that have been parallelized using our system.
Research on parallel algorithm for sequential pattern mining
NASA Astrophysics Data System (ADS)
Zhou, Lijuan; Qin, Bai; Wang, Yu; Hao, Zhongxiao
2008-03-01
Sequential pattern mining is the mining of frequent sequences related to time or other orders from the sequence database. Its initial motivation is to discover the laws of customer purchasing in a time section by finding the frequent sequences. In recent years, sequential pattern mining has become an important direction of data mining, and its application field has not been confined to the business database and has extended to new data sources such as Web and advanced science fields such as DNA analysis. The data of sequential pattern mining has characteristics as follows: mass data amount and distributed storage. Most existing sequential pattern mining algorithms haven't considered the above-mentioned characteristics synthetically. According to the traits mentioned above and combining the parallel theory, this paper puts forward a new distributed parallel algorithm SPP(Sequential Pattern Parallel). The algorithm abides by the principal of pattern reduction and utilizes the divide-and-conquer strategy for parallelization. The first parallel task is to construct frequent item sets applying frequent concept and search space partition theory and the second task is to structure frequent sequences using the depth-first search method at each processor. The algorithm only needs to access the database twice and doesn't generate the candidated sequences, which abates the access time and improves the mining efficiency. Based on the random data generation procedure and different information structure designed, this paper simulated the SPP algorithm in a concrete parallel environment and implemented the AprioriAll algorithm. The experiments demonstrate that compared with AprioriAll, the SPP algorithm had excellent speedup factor and efficiency.
Steven Y. Newell; Robert D. Fallon
1982-01-01
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
Shah, Ronak C.
1991-01-01
I'sge III. A Review III. B MasPar System Architecture 18 III. C MasPar FORTRAN 21 III. D MasPar Programming Environment IV MLOCFES: PARALLEL VERSION IV. A Potential Regions of Parallelism in LOCFES IV. B FORTRAN gg Adaptations IV. C Program.... 2 MasPar MP-1 System Diagram (Adapted from MasPar System Overview). . . 19 3 The flow of control. 31 LIST OF TABLES TABLE Page Analytical vs computational (MLOCFES) solution for I = 1, K = 1, and L=1 Analytical vs computational (MLOCFES...
An Approach To Portable Parallel Programs
Charles C. Weems Jr
1992-01-01
Parallel architectures vary greatly in their organizations. These differences arise naturally from designing machines to fit different problem domains, and from different physical and cost constraints. Thus, the world is, and will continue to be, populated with parallel processors having significantly different organizations and hence, incompatible programming models: a program written specifically for one parallel processor does not transport directly
An Optimizing Algorithm for Extended CAM Processors with Threshold Search
Takao TOTSUKA; Yuichiro MIYAOKA; Yuichiro ISHIKAWA; Nozomu TOGAWA; Masao YANAGISAWA; Tatsuo OHTSUKI
An extended content addressable memory (CAM) realizes not only conventional equivalent search but parallel threshold search such as less-than search and greater-than search. In order to use the parallel processing function of CAM, parallel processing circuits are needed around a CAM cell array. Furthermore every application requires its specific CAM cell array and peripheral circuits. This paper proposes an optimizing
316 -- 2008/10/16 -- 10:15 -- page 1 -- le-tex ii ii ii Earthquake Location, Direct, Global-Search Methods 1 Earthquake Location, Direct, Global-Search Methods ANTHONY LOMAX1, ALBERTO MICHELINI2,1 ANDREW Roma, Italy5 3 ECOSSE (Edinburgh Collaborative6 of Subsurface Science and Engineering),7 Grant
NASA Astrophysics Data System (ADS)
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
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.
Abreu, P.; ,
2012-01-01
Observations of cosmic ray arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects drawn from the Veron-Cetty Veron catalog. In this paper we report on the use of three catalog independent methods to search for anisotropy. The 2pt-L, 2pt+ and 3pt methods, each giving a different measure of self-clustering in arrival directions, were tested on mock cosmic ray data sets to study the impacts of sample size and magnetic smearing on their results, accounting for both angular and energy resolutions. If the sources of UHECRs follow the same large scale structure as ordinary galaxies in the local Universe and if UHECRs are deflected no more than a few degrees, a study of mock maps suggests that these three methods can efficiently respond to the resulting anisotropy with a P-value = 1.0% or smaller with data sets as few as 100 events. Using data taken from January 1, 2004 to July 31, 2010 we examined the 20, 30, ..., 110 highest energy events with a corresponding minimum energy threshold of about 51 EeV. The minimum P-values found were 13.5% using the 2pt-L method, 1.0% using the 2pt+ method and 1.1% using the 3pt method for the highest 100 energy events. In view of the multiple (correlated) scans performed on the data set, these catalog-independent methods do not yield strong evidence of anisotropy in the highest energy cosmic rays.
Abreu, P.; Andringa, S. [LIP and Instituto Superior Técnico, Technical University of Lisbon (Portugal); Aglietta, M. [Istituto di Fisica dello Spazio Interplanetario (INAF), Università di Torino and Sezione INFN, Torino (Italy); Ahlers, M. [University of Wisconsin, Madison, WI (United States); Ahn, E.J. [Fermilab, Batavia, IL (United States); Albuquerque, I.F.M. [Universidade de São Paulo, Instituto de Física, São Paulo, SP (Brazil); Allard, D. [Laboratoire AstroParticule et Cosmologie (APC), Université Paris 7, CNRS-IN2P3, Paris (France); Allekotte, I. [Centro Atómico Bariloche and Instituto Balseiro (CNEA-UNCuyo-CONICET), San Carlos de Bariloche (Argentina); Allen, J. [New York University, New York, NY (United States); Allison, P. [Ohio State University, Columbus, OH (United States); Almela, A. [Universidad Tecnológica Nacional - Facultad Regional Buenos Aires, Buenos Aires (Argentina); Castillo, J. Alvarez [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico); Alvarez-Muñiz, J. [Universidad de Santiago de Compostela (Spain); Ambrosio, M.; Aramo, C. [Università di Napoli 'Federico II' and Sezione INFN, Napoli (Italy); Aminaei, A. [IMAPP, Radboud University Nijmegen (Netherlands); Anchordoqui, L. [University of Wisconsin, Milwaukee, WI (United States); Antici'c, T. [Rudjer Boškovi'c Institute, 10000 Zagreb (Croatia); Arganda, E. [IFLP, Universidad Nacional de La Plata and CONICET, La Plata (Argentina); Arqueros, F., E-mail: auger_spokesperson@fnal.gov [Universidad Complutense de Madrid, Madrid (Spain); Collaboration: Pierre Auger Collaboration; and others
2012-04-01
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.
NSDL National Science Digital Library
Michael Horton
2009-05-30
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
Max Tegmark
2003-01-01
I survey physics theories involving parallel universes, which form a natural four-level hierarchy of multiverses allowing progressively greater diversity. Level I: A generic prediction of inflation is an infinite ergodic universe, which contains Hubble volumes realizing all initial conditions - including an identical copy of you about 10^{10^29} meters away. Level II: In chaotic inflation, other thermalized regions may have
Petersohn, Anja; Bernhardt, Jörg; Gerth, Ulf; Höper, Dirk; Koburger, Torsten; Völker, Uwe; Hecker, Michael
1999-01-01
A consensus-directed search for ?B promoters was used to locate potential candidates for new ?B-dependent genes in Bacillus subtilis. Screening of those candidates by oligonucleotide hybridizations with total RNA from exponentially growing or ethanol-stressed cells of the wild type as well as a sigB mutant revealed 22 genes that required ?B for induction by ethanol. Although almost 50% of the proteins encoded by the newly discovered ?B-dependent stress genes seem to be membrane localized, biochemical functions have so far not been defined for any of the gene products. Allocation of the genes to the ?B-dependent stress regulon may indicate a potential function in the establishment of a multiple stress resistance. AldY and YhdF show similarities to NAD(P)-dependent dehydrogenases and YdbP to thioredoxins, supporting our suggestion that ?B-dependent proteins may be involved in the maintenance of the intracellular redox balance after stress. PMID:10482513
Fornengo, N.; Scopel, S. [Department of Physics, Sogang University Seoul, Korea, 121-742 (Korea, Republic of); Bottino, A. [Dipartimento di Fisica Teorica, Universita di Torino Istituto Nazionale di Fisica Nucleare, Sezione di Torino via P. Giuria 1, I-10125 Torino (Italy)
2011-01-01
We examine the status of light neutralinos in an effective minimal supersymmetric extension of the standard model at the electroweak scale which was considered in the past and discussed in terms of the available data of direct searches for dark matter particles. Our reanalysis is prompted by new measurements at the Tevatron and B factories which might potentially provide significant constraints on the minimal supersymmetric extension of the standard model. Here we examine in detail all these new data and show that the present published results from the Tevatron and B factories have only a mild effect on the original light-neutralino population. This population, which fits quite well the DAMA/LIBRA annual modulation data, would also agree with the preliminary results of CDMS, CoGeNT, and CRESST, should these data, which are at present only hints of excesses of events over the expected backgrounds, be interpreted as authentic signals of dark matter. For the neutralino mass we find a lower bound of 7-8 GeV. Our results differ from some recent conclusions by other authors because of a few crucial points which we try to single out and elucidate.
ZEN2: a narrow J-band search for z ~ 9 Ly? emitting galaxies directed towards three lensing clusters
NASA Astrophysics Data System (ADS)
Willis, J. P.; Courbin, F.; Kneib, J.-P.; Minniti, D.
2008-03-01
We present the results of a continuing survey to detect Ly? emitting galaxies at redshifts z ~ 9: the `z equals nine' (ZEN) survey. We have obtained deep VLT Infrared Spectrometer and Array Camera observations in the narrow J-band filter NB119 directed towards three massive lensing clusters: Abell clusters 1689, 1835 and 114. The foreground clusters provide a magnified view of the distant Universe and permit a sensitive test for the presence of very high redshift galaxies. We search for z ~ 9 Ly? emitting galaxies displaying a significant narrow-band excess relative to accompanying J-band observations that remain undetected in Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) optical images of each field. No sources consistent with this criterion are detected above the unlensed 90 per cent point-source flux limit of the narrow-band image, FNB = 3.7 × 10-18ergs-1cm-2. To date, the total coverage of the ZEN survey has sampled a volume at z ~ 9 of approximately 1700 comoving Mpc3 to a Ly? emission luminosity of 1043ergs-1. We conclude by considering the prospects for detecting z ~ 9 Ly? emitting galaxies in light of both observed galaxy properties at z < 7 and simulated populations at z > 7.
Parallel hierarchical global illumination
Snell, Q.O.
1997-10-08
Solving the global illumination problem is equivalent to determining the intensity of every wavelength of light in all directions at every point in a given scene. The complexity of the problem has led researchers to use approximation methods for solving the problem on serial computers. Rather than using an approximation method, such as backward ray tracing or radiosity, the authors have chosen to solve the Rendering Equation by direct simulation of light transport from the light sources. This paper presents an algorithm that solves the Rendering Equation to any desired accuracy, and can be run in parallel on distributed memory or shared memory computer systems with excellent scaling properties. It appears superior in both speed and physical correctness to recent published methods involving bidirectional ray tracing or hybrid treatments of diffuse and specular surfaces. Like progressive radiosity methods, it dynamically refines the geometry decomposition where required, but does so without the excessive storage requirements for ray histories. The algorithm, called Photon, produces a scene which converges to the global illumination solution. This amounts to a huge task for a 1997-vintage serial computer, but using the power of a parallel supercomputer significantly reduces the time required to generate a solution. Currently, Photon can be run on most parallel environments from a shared memory multiprocessor to a parallel supercomputer, as well as on clusters of heterogeneous workstations.
Analytic Guided-Search Model of Human Performance Accuracy in Target- Localization Search Tasks
NASA Technical Reports Server (NTRS)
Eckstein, Miguel P.; Beutter, Brent R.; Stone, Leland S.
2000-01-01
Current models of human visual search have extended the traditional serial/parallel search dichotomy. Two successful models for predicting human visual search are the Guided Search model and the Signal Detection Theory model. Although these models are inherently different, it has been difficult to compare them because the Guided Search model is designed to predict response time, while Signal Detection Theory models are designed to predict performance accuracy. Moreover, current implementations of the Guided Search model require the use of Monte-Carlo simulations, a method that makes fitting the model's performance quantitatively to human data more computationally time consuming. We have extended the Guided Search model to predict human accuracy in target-localization search tasks. We have also developed analytic expressions that simplify simulation of the model to the evaluation of a small set of equations using only three free parameters. This new implementation and extension of the Guided Search model will enable direct quantitative comparisons with human performance in target-localization search experiments and with the predictions of Signal Detection Theory and other search accuracy models.
Parallel MATLAB at VT: Parallel For Loops
Crawford, T. Daniel
Parallel MATLAB at VT: Parallel For Loops John Burkardt (FSU) Gene Cliff (AOE/ICAM - ecliff Research Computing ICAM: Interdisciplinary Center for Applied Mathematics 1 / 72 #12;MATLAB Parallel Example ODE SWEEP Example FMINCON Example Conclusion 2 / 72 #12;INTRO: Parallel MATLAB Parallel MATLAB
Parallel MATLAB at VT: Parallel For Loops
Crawford, T. Daniel
Parallel MATLAB at VT: Parallel For Loops John Burkardt (FSU) Gene Cliff (AOE/ICAM - ecliff Research Computing ICAM: Interdisciplinary Center for Applied Mathematics 1 / 71 #12;MATLAB Parallel Example ODE SWEEP Example FMINCON Example Conclusion 2 / 71 #12;INTRO: Parallel MATLAB Parallel MATLAB
Directed Graphs digraph search
Sedgewick, Robert
web page hyperlink game board position legal move telephone person placed call food web species? Shortest path. Find best route from s to t in a weighted digraph PageRank. What is the importance of a web in a map hyperlinks connecting web pages dependencies in software modules prey-predator relationships #12
Parallel Hardware and Parallel Software: a Reconciliation
Zanibbi, Richard
Parallel Hardware and Parallel Software: a Reconciliation Peter Welch Computing Laboratory University of Kent, Canterbury, UK Abstract Parallel hardware is commercially marketed today at all levels of gran- ularity - from
Load Balancing Instabilities due to Time Delays in Parallel Computations
naturally to a parallel decomposition of the DNA database search problem while providing orders of magnitude database and in the demand for searches of the database necessitates migration to a parallel computing to an expected waiting tim* *e, normalizing to account for differences among CEs, and aggregates the behavior
Load Balancing Instabilities due to Time Delays in Parallel Computations
][4][3][17][16] lead naturally to a parallel decomposition of the DNA database search problem while providing orders of the NDIS database and in the demand for searches of the database necessitates migration to a parallel waiting time, normalizing to account for di#erences among CEs, and aggregates the behavior of each queue
Computer-Aided Parallelizer and Optimizer
NASA Technical Reports Server (NTRS)
Jin, Haoqiang
2011-01-01
The Computer-Aided Parallelizer and Optimizer (CAPO) automates the insertion of compiler directives (see figure) to facilitate parallel processing on Shared Memory Parallel (SMP) machines. While CAPO currently is integrated seamlessly into CAPTools (developed at the University of Greenwich, now marketed as ParaWise), CAPO was independently developed at Ames Research Center as one of the components for the Legacy Code Modernization (LCM) project. The current version takes serial FORTRAN programs, performs interprocedural data dependence analysis, and generates OpenMP directives. Due to the widely supported OpenMP standard, the generated OpenMP codes have the potential to run on a wide range of SMP machines. CAPO relies on accurate interprocedural data dependence information currently provided by CAPTools. Compiler directives are generated through identification of parallel loops in the outermost level, construction of parallel regions around parallel loops and optimization of parallel regions, and insertion of directives with automatic identification of private, reduction, induction, and shared variables. Attempts also have been made to identify potential pipeline parallelism (implemented with point-to-point synchronization). Although directives are generated automatically, user interaction with the tool is still important for producing good parallel codes. A comprehensive graphical user interface is included for users to interact with the parallelization process.
Parallel acquisition of PN sequences in DS/SS systems
Chawla, K.K.; Sarwate, D.V. (Univ. of Illinois, Urbana, IL (United States))
1994-05-01
We investigate methods for the parallel acquisition of a PN sequence in a baseband direct sequence spread spectrum system. Four different schemes are considered: the optimal estimation scheme, the maximum-likelihood estimation scheme, a hypothesis-testing scheme that searches over all shifts, and a locally optimum detection scheme. Approximate expressions for the probability of error are derived for the first and last of these schemes and compared with the actual error probabilities obtained via Monte Carlo simulation. Monte Carlo simulation is also used to obtain the error probabilities of the other two schemes and the results for all the schemes are compared. Since the obvious methods of implementing a parallel acquisition scheme require large amounts of hardware or excessive computation, we outline a technique that can be used to reduce the amount of computation. 10 refs.
NSDL National Science Digital Library
NCSA
Several tutorials on parallel computing. Overview of parallel computing. Porting and code parallelization. Scalar, cache, and parallel code tuning. Timing, profiling and performance analysis. Overview of IBM Regatta P690.
Sampath, Rahul S [ORNL; Sundar, Hari [Siemens Corporate Research; Veerapaneni, Shravan [New York University
2010-01-01
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.
Y. Nakajima; A. Goldschmidt; M. Long; D. Nygren; C. Oliveira; J. Renner
2015-05-14
Directional sensitivity is one of the most important aspects of WIMP dark matter searches. Yet, making the direction of nuclear recoil visible with large target masses is a challenge. To achieve this, we are exploring a new method of detecting directions of short nuclear recoil tracks in high-pressure Xe gas, down to a few micron long, by utilizing columnar recombination. Columnar recombination changes the scintillation and ionization yields depending on the angle between a track and the electric field direction. In order to realize this, efficient cooling of electrons is essential. Trimethylamine(TMA) is one of the candidate additives to gaseous Xe in order to enhance the effect, not only by efficiently cooling the electrons, but also by increasing the amount of columnar recombination by Penning transfer. We performed a detailed simulation of ionization electrons transport created by nuclear recoils in a Xe + TMA gas mixture, and evaluated the size of the columnar recombination signal. The results show that the directionality signal can be obtained for a track longer than a few micrometers in some ideal cases. Although more studies with realistic assumptions are still needed in order to assess feasibility of this technique, this potentially opens a new possibility for dark matter searches.
NASA Astrophysics Data System (ADS)
Larsson, P. O.; Batsch, T.; Kirchner, R.; Klepper, O.; Kurcewicz, W.; Roeckl, E.; Schardt, D.; Feix, W. F.; Nyman, G.; Tidemand-Petersson, P.
1983-02-01
The earlier preliminary assignment of a 1,055±6 keV proton line to direct proton decay of147Tm is supported by cross bombardment measurements and by a negative result from a positron-proton coincidence experiment. The half-life was remeasured to be 0.56 ±0.04s. For two types of thermal ion sources, overall efficiencies were estimated for on-line mass separation of known short-lived isotopes of promethium, europium, terbium, and holmium. Direct proton decay was searched for among very neutron-deficient isotopes of these elements, and of iodine and caesium. No evidence for direct proton decay was found. Based on estimated overall efficiencies, on calculated cross-sections, and on predictions from the gross-theory of ? decay, half-life limits for direct proton decay were deduced.
Max Tegmark
2003-02-07
I survey physics theories involving parallel universes, which form a natural four-level hierarchy of multiverses allowing progressively greater diversity. Level I: A generic prediction of inflation is an infinite ergodic universe, which contains Hubble volumes realizing all initial conditions - including an identical copy of you about 10^{10^29} meters away. Level II: In chaotic inflation, other thermalized regions may have different effective physical constants, dimensionality and particle content. Level III: In unitary quantum mechanics, other branches of the wavefunction add nothing qualitatively new, which is ironic given that this level has historically been the most controversial. Level IV: Other mathematical structures give different fundamental equations of physics. The key question is not whether parallel universes exist (Level I is the uncontroversial cosmological concordance model), but how many levels there are. I discuss how multiverse models can be falsified and argue that there is a severe "measure problem" that must be solved to make testable predictions at levels II-IV.
Parallel MATLAB at VT: Parallel For Loops
Crawford, T. Daniel
Parallel MATLAB at VT: Parallel For Loops John Burkardt (FSU) Gene Cliff (AOE/ICAM - ecliff Research Computing ICAM: Interdisciplinary Center for Applied Mathematics 1 / 56 #12;Matlab Parallel ODE SWEEP Example MD Example Conclusion 2 / 56 #12;INTRO: Parallel Matlab In a previous lecture we
Lori S. Mestre; Christine Turner; Beth Lang; Barbara Morgan
2007-01-01
The Five College Libraries of Western Massachusetts have a long-standing tradition of collaborating on technology projects which improve our communities' access to information resources. After investigating various link resolver and federated search products in 2002, the Five College Librarians' Council signed a three-year contract with Ex Libris in spring 2003 to host SFX link resolver and MetaLib federated search installations.
Utilizing parallel optimization in computational fluid dynamics
NASA Astrophysics Data System (ADS)
Kokkolaras, Michael
1998-12-01
General problems of interest in computational fluid dynamics are investigated by means of optimization. Specifically, in the first part of the dissertation, a method of optimal incremental function approximation is developed for the adaptive solution of differential equations. Various concepts and ideas utilized by numerical techniques employed in computational mechanics and artificial neural networks (e.g. function approximation and error minimization, variational principles and weighted residuals, and adaptive grid optimization) are combined to formulate the proposed method. The basis functions and associated coefficients of a series expansion, representing the solution, are optimally selected by a parallel direct search technique at each step of the algorithm according to appropriate criteria; the solution is built sequentially. In this manner, the proposed method is adaptive in nature, although a grid is neither built nor adapted in the traditional sense using a-posteriori error estimates. Variational principles are utilized for the definition of the objective function to be extremized in the associated optimization problems, ensuring that the problem is well-posed. Complicated data structures and expensive remeshing algorithms and systems solvers are avoided. Computational efficiency is increased by using low-order basis functions and concurrent computing. Numerical results and convergence rates are reported for a range of steady-state problems, including linear and nonlinear differential equations associated with general boundary conditions, and illustrate the potential of the proposed method. Fluid dynamics applications are emphasized. Conclusions are drawn by discussing the method's limitations, advantages, and possible extensions. The second part of the dissertation is concerned with the optimization of the viscous-inviscid-interaction (VII) mechanism in an airfoil flow analysis code. The VII mechanism is based on the concept of a transpiration velocity boundary condition, whose convergence to steady state is accelerated. The number of variables in the associated optimization problem is reduced by means of function approximation concepts to ensure high number of parallel processors to number of necessary function evaluations ratio. Numerical results are presented for the NACA-0012 and the supercritical RAE-2822 airfoils subject to transonic flow conditions using a parallel direct search technique. They exhibit a satisfactory level of accuracy. Speed-up depends on the number of available computational units and increases for more challenging flow conditions and airfoil geometries. The enhanced code constitutes a useful tool for airfoil flow analysis and design and an acceptable alternative to computationally expensive high fidelity codes.
Taylor, Frank E.
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=7??TeV. The measurement is based on ...
NASA Astrophysics Data System (ADS)
Meadors, Grant; Goetz, Evan; Riles, Keith
2014-03-01
Scorpius X-1 and similar low-mass X-ray binary (LMXB) systems with neutron stars contain favorable conditions for the emission of continuous gravitational waves (GW). Companion star accretion is believed to recycle the neutron star, spinning it up to high rotational speeds. That accretion could also induce non-axisymmetries in the neutron star, leading to detectable GW emission. Advanced LIGO and other 2nd-generation interferometric observatories will permit searches for such gravitational waves using new algorithms, including the TwoSpect program, which was developed originally for all-sky binary searches. In this presentation we discuss an implementation of TwoSpect using fine templates in parameter space at the initial stage and optimized to search for LMXBs, such as Sco X-1, where some of the orbital parameters are known. Results from simulations will be shown.
Predicting performance of parallel computations
NASA Technical Reports Server (NTRS)
Mak, Victor W.; Lundstrom, Stephen F.
1990-01-01
An accurate and computationally efficient method for predicting the performance of a class of parallel computations running on concurrent systems is described. A parallel computation is modeled as a task system with precedence relationships expressed as a series-parallel directed acyclic graph. Resources in a concurrent system are modeled as service centers in a queuing network model. Using these two models as inputs, the method outputs predictions of expected execution time of the parallel computation and the concurrent system utilization. The method is validated against both detailed simulation and actual execution on a commercial multiprocessor. Using 100 test cases, the average error of the prediction when compared to simulation statistics is 1.7 percent, with a standard deviation of 1.5 percent; the maximum error is about 10 percent.
Predicting performance of parallel computations
Mak, V.W. (Distributed Software Research Group, Bell Communications Research, Morristown, NJ (US)); Lundstrom, S.F. (Stanford Univ., CA (USA). Computer Systems Lab.)
1990-07-01
This paper describes an accurate and computationally efficient method for predicting performance of a class of parallel computations running on concurrent systems. Earlier work either dealt with very restricted computation structures or used methods with exponential complexity. A parallel computation is modeled as a task system with precedence relationships expressed as a series-parallel directed acyclic graph. Resources in a concurrent system are modeled as service centers in a queueing network model. Using these two models as inputs, the method outputs predictions of expected execution time of the parallel computation and the concurrent system utilization. The method has been validated against both detailed simulation and actual execution on a commercial multiprocessor. Using one hundred test cases, the average error of the prediction when compared to simulation statistics was 1.7% with a standard deviation of 1.5%, and the maximum error was about 10%.
NASA Astrophysics Data System (ADS)
Stokes, Benjamin Taylor
2006-06-01
Although the existence of cosmic rays with energies extending well above 10^19 eV has been confirmed, their origin remains one of the most important questions in astro-particle physics today. The High Resolution Fly's Eye Detector (HiRes) detects Ultra High Energy Cosmic Rays (UHECRs) by employing the air- fluorescence technique to observe Extensive Air Showers (EAS) in the atmosphere over Dugway, Utah. It has been collecting data since May 1997 during which time over 1500 events with energies greater than 10 18.5 eV have been observed in monocular mode. These events are characterized by arrival directions with asymmetric uncertainties, which are explored in detail for this study. Multiple methods are developed and utilized to search for anisotropies in the arrival directions. A primary emphasis is placed upon previous reported observations that suggested small-scale clustering and global dipole biases. Additionally a new method for searching for anisotropies is explored. While all conclusions are statistically limited in their applicability, the sensitivities are shown to be compatible with prior experiments. However, all evidence to date on the arrival directions of the UHECRs observed by HiRes in monocular mode is consistent with an isotropic distribution.
NASA Technical Reports Server (NTRS)
Nguyen, D. T.; Al-Nasra, M.; Zhang, Y.; Baddourah, M. A.; Agarwal, T. K.; Storaasli, O. O.; Carmona, E. A.
1991-01-01
Several parallel-vector computational improvements to the unconstrained optimization procedure are described which speed up the structural analysis-synthesis process. A fast parallel-vector Choleski-based equation solver, pvsolve, is incorporated into the well-known SAP-4 general-purpose finite-element code. The new code, denoted PV-SAP, is tested for static structural analysis. Initial results on a four processor CRAY 2 show that using pvsolve reduces the equation solution time by a factor of 14-16 over the original SAP-4 code. In addition, parallel-vector procedures for the Golden Block Search technique and the BFGS method are developed and tested for nonlinear unconstrained optimization. A parallel version of an iterative solver and the pvsolve direct solver are incorporated into the BFGS method. Preliminary results on nonlinear unconstrained optimization test problems, using pvsolve in the analysis, show excellent parallel-vector performance indicating that these parallel-vector algorithms can be used in a new generation of finite-element based structural design/analysis-synthesis codes.
Huske, Nils Kristian; /Paris U., VI-VII
2010-09-01
We have presented results in two different yet strongly linked aspects of Higgs boson physics. We have learned about the importance of the Higgs boson for the fate of the Standard Model, being either only a theory limited to explaining phenomena at the electroweak scale or, if the Higgs boson lies within a mass range of 130 < m{sub H} < 160 GeV the SM would remain a self consistent theory up to highest energy scales O(m{sub Pl}). This could have direct implications on theories of cosmological inflation using the Higgs boson as the particle giving rise to inflation in the very early Universe, if it couples non-minimally to gravity, an effect that would only become significant at very high energies. After understanding the immense meaning of proving whether the Higgs boson exists and if so, at which mass, we have presented a direct search for a Higgs boson in associated production with a W boson in a mass range 100 < m{sub H} < 150 GeV. A light Higgs boson is favored regarding constraints from electroweak precision measurements. As a single analysis is not yet sensitive for an observation of the Higgs boson using 5.3 fb{sup -1} of Tevatron data, we set limits on the production cross section times branching ratio. At the Tevatron, however, we are able to combine the sensitivity of our analyses not only across channels or analyses at a single experiment but also across both experiments, namely CDF and D0. This yields to the so-called Tevatron Higgs combination which, in total, combines 129 analyses from both experiments with luminosities of up to 6.7 fb{sup -1}. The results of a previous Tevatron combination led to the first exclusion of possible Higgs boson masses since the LEP exclusion in 2001. The latest Tevatron combination from July 2010 can be seen in Fig. 111 and limits compared to the Standard Model expectation are listed in Table 23. It excludes a SM Higgs boson in the regions of 100 < m{sub H} < 109 GeV as well as 158 < m{sub H} < 175 GeV based on the observed final limits at 95% C.L. In the most interesting low mass region between 115 and 135 GeV, even the full Tevatron combination is not yet sensitive enough to exclude a Higgs boson, or to even prove its existence with a meaningful significance. Fig. 112 shows a projection plot for sensitivity to the SM Higgs boson at the Tevatron as a measure of increasing luminosity. The 10 fb{sup -1} projection is a rather conservative outlook for the coming year of data taking as the Tevatron runs smoothly and the run till the end of 2011 is assured. By now, already 9 fb{sup -1} have been recorded by the two experiments. As the extrapolation plot shows, this amount of luminosity will allow to exclude the Higgs boson over a wide mass range at a 95% C.L. With the LHC at CERN now running and successfully collecting first data, it is worth looking at projections of Higgs boson sensitivity at the current center of mass energy of 7 TeV of the LHC accelerator. Fig. 113 shows a projection of a possible SM Higgs boson exclusion using 1 fb{sup -1} of LHC data collected by the ATLAS experiment. An exclusion is expected between 135 and 188 GeV at 95% C.L., combining the three decay channels H {yields} WW, H {yields} ZZ and H {yields} {gamma}{gamma}. A combination between LHC experiments would possibly yield an even broader range of excluded Higgs boson mass points. Therefore, whether at the Tevatron or the LHC, exciting times in the exclusion or possible discovery of the SM Higgs boson lie ahead.
C. B. Winkelmann; J. Elbs; Yu. M. Bunkov; E. Collin; H. Godfrin; M. Krusius
2006-11-28
We report on the calibration of a superfluid $^3$He bolometer developed for the search of non-baryonic Dark Matter. Precise thermometry is achieved by the direct measurement of thermal excitations using Vibrating Wire Resonators (VWRs). The heating pulses for calibration were produced by the direct quantum process of quasiparticle generation by other VWRs present. The bolometric calibration factor is analyzed as a function of temperature and excitation level of the sensing VWR. The calibration is compared to bolometric measurements of the nuclear neutron capture reaction and heat depositions by cosmic muons and low energy electrons. The comparison allows a quantitative estimation of the ultra-violet scintillation rate of irradiated helium, demonstrating the possibility of efficient electron recoil event rejection.
NASA Astrophysics Data System (ADS)
Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Khalek, S. Abdel; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmad, A.; Ahmadov, F.; Aielli, G.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Gonzalez, B. Alvarez; Alviggi, M. G.; Amako, K.; Coutinho, Y. Amaral; Amelung, C.; Amidei, D.; Ammosov, V. V.; Santos, S. P. Amor Dos; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Bella, L. Aperio; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Mayes, J. Backus; Badescu, E.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, S.; Balek, P.; Balli, F.; Banas, E.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bannoura, A. A. E.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; da Costa, J. Barreiro Guimarães; Bartoldus, R.; Barton, A. E.; Bartos, P.; Bartsch, V.; Bassalat, A.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, K.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belloni, A.; Beloborodova, O. L.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Garcia, J. A. Benitez; Benjamin, D. P.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Kuutmann, E. Bergeaas; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernard, C.; Bernat, P.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Bessidskaia, O.; Besson, N.; Betancourt, C.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; De Mendizabal, J. Bilbao; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boek, T. T.; Bogaerts, J. A.; Bogdanchikov, A. G.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borri, M.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutouil, S.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Brendlinger, K.; Brennan, A. J.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, G.; Brown, J.; de Renstrom, P. A. Bruckman; Bruncko, D.; Bruneliere, R.
2014-04-01
A search for the direct production of charginos and neutralinos in final states with three leptons and missing transverse momentum is presented. The analysis is based on 20.3 fb-1 of = 8 TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with the Standard Model expectations and limits are set in R-parity-conserving phenomenological Minimal Supersymmetric Standard Models and in simplified supersymmetric models, significantly extending previous results. For simplified supersymmetric models of direct chargino and next-to-lightest neutralino production with decays to lightest neutralino via either all three generations of sleptons, staus only, gauge bosons, or Higgs bosons, and masses are excluded up to 700 GeV, 380 GeV, 345 GeV, or 148 GeV respectively, for a massless . [Figure not available: see fulltext.
NASA Astrophysics Data System (ADS)
Aad, G.; Abbott, B.; Abdallah, J.; Khalek, S. Abdel; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmad, A.; Ahmadov, F.; Aielli, G.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnold, H.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Backus Mayes, J.; Badescu, E.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, S.; Balek, P.; Balli, F.; Banas, E.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bannoura, A. A. E.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Guimarães da Costa, J. Barreiro; Bartoldus, R.; Barton, A. E.; Bartos, P.; Bartsch, V.; Bassalat, A.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, K.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belloni, A.; Beloborodova, O. L.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Garcia, J. A. Benitez; Benjamin, D. P.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernard, C.; Bernat, P.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Bessidskaia, O.; Besson, N.; Betancourt, C.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boek, T. T.; Bogaerts, J. A.; Bogdanchikov, A. G.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borri, M.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutouil, S.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Brendlinger, K.; Brennan, A. J.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, G.; Brown, J.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.
2014-06-01
A search is presented for direct top squark pair production using events with at least two leptons including a same-flavour opposite-sign pair with invariant mass consistent with the boson mass, jets tagged as originating from -quarks and missing transverse momentum. The analysis is performed with proton-proton collision data at collected with the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of 20.3 fb. No excess beyond the Standard Model expectation is observed. Interpretations of the results are provided in models based on the direct pair production of the heavier top squark state () followed by the decay to the lighter top squark state () via , and for pair production in natural gauge-mediated supersymmetry breaking scenarios where the neutralino () is the next-to-lightest supersymmetric particle and decays producing a boson and a gravitino () via the process.
Programming environments for highly parallel multiprocessors
A. P. Reeves
1988-01-01
Emerging highly parallel multiprocessors offer an exciting alternative to conventional pipelined supercomputers for a variety of computationally intensive scientific applications. A factor that has impeded the introduction of these multiprocessor systems is that conventional languages, such as Fortran, cannot be directly used and new programming techniques must be mastered. A key issue for highly parallel systems is the development of
Hemispheric asymmetries in visual search
William Poynter; Candice Roberts
2011-01-01
We conducted two visual search experiments, and found that target-detection accuracy and speed were better when the target was projected to the right hemisphere in the feature search condition and better when the target was projected to the left hemisphere in the feature-conjunction search condition. We propose that the highly efficient, so-called parallel search performance characteristic of feature search is
Fermilab Experiment E871
1 Search for direct CP violation in \\Lambda and \\Xi hyperon decays C. G. White, a R. A. Burnstein for direct CP violation in \\Xi \\Gamma ( Â¯ \\Xi + ) and \\Lambda ( Â¯ \\Lambda) decays is underway at FNAL. Experiment E871 (HyperCP) intends to perform a precision measurement of the angular distribution of protons
Parallel Hybrid Particle Swarm Optimization and Applications in Geotechnical Engineering
Youliang Zhang; Domenico Gallipoli; Charles Augarde
2009-01-01
A novel parallel hybrid particle swarm optimization algorithm named hmPSO is presented. The new algorithm combines particle\\u000a swarm optimization (PSO) with a local search method which aims to accelerate the rate of convergence. The PSO provides initial\\u000a guesses to the local search method and the local search accelerates PSO with its solutions. The hybrid global optimization\\u000a algorithm adjusts its searching
S. Burgos; E. Daw; J. Forbes; C. Ghag; M. Gold; C. Hagemann; V. A. Kudryavtsev; T. B. Lawson; D. Loomba; P. Majewski; D. Muna; A. St J. Murphy; G. G. Nicklin; S. M. Paling; A. Petkov; S. J. S. Plank; M. Robinson; N. Sanghi; D. P. Snowden-Ifft; N. J. C. Spooner; J. Turk; E. Tziaferi
2009-01-01
We present first evidence for the so-called head–tail directional signature of neutron-induced nuclear recoil tracks at energies down to 1.5keV\\/amu using the DRIFT-IIc dark matter detector. This regime is appropriate for recoils induced by Weakly Interacting Massive Particle (WIMPs) but one where the differential ionization is poorly understood. We show that the distribution of recoil energies and directions induced here
Topic-based Index Partitions for Efficient and Effective Selective Search
Callan, Jamie
Keywords selective searching, federated search, document clustering 1. INTRODUCTION TraditionallyTopic-based Index Partitions for Efficient and Effective Selective Search Anagha Kulkarni and Jamie divided into shards that are distributed across multiple computers and searched in parallel to provide
Medipix2 parallel readout system
NASA Astrophysics Data System (ADS)
Fanti, V.; Marzeddu, R.; Randaccio, P.
2003-08-01
A fast parallel readout system based on a PCI board has been developed in the framework of the Medipix collaboration. The readout electronics consists of two boards: the motherboard directly interfacing the Medipix2 chip, and the PCI board with digital I/O ports 32 bits wide. The device driver and readout software have been developed at low level in Assembler to allow fast data transfer and image reconstruction. The parallel readout permits a transfer rate up to 64 Mbytes/s. http://medipix.web.cern ch/MEDIPIX/
Parallel Composition Communication and Allow Hiding Parallel Processes
Groote, Jan Friso
Parallel Composition Communication and Allow Hiding Parallel Processes Mohammad Mousavi Eindhoven University of Technology, The Netherlands Requirement Analysis and Design Verification, 2008-2009 Mousavi: Parallel Processes #12;Parallel Composition Communication and Allow Hiding Overview Motivation Parallel
W. Daniel Hillis; Guy L. Steele Jr.
1986-01-01
Parallel computers with tens of thousands of processors are typically programmed in a data parallel style, as opposed to the control parallel style used in multiprocessing. The success of data parallel algorithms—even on problems that at first glance seem inherently serial—suggests that this style of programming has much wider applicability than was previously thought.
Introduction to Parallel Programming
Introduction to Parallel Programming 1Tuesday, April 17, 12 #12;Overview · Parallel programming allows the user to use multiple cpus concurrently · Reasons for parallel execution: · shorten execution expect as a function of the number of processors (N) used and the code fraction that is parallel (p). T(1
Introduction to Parallel Programming
Alvarado, Alejandro Sánchez
Introduction to Parallel Programming Martin Cuma Center for High Performance Computing University of Utah mcuma@chpc.utah.edu #12;Overview · Types of parallel computers. · Parallel programming options. · How to write parallel applications. · How to compile. · How to debug/profile. · Summary, future
Radhakrishnan, S.
1990-01-01
The quest for efficient parallel algorithms for graph related problems necessitates not only fast computational schemes but also requires insights into their inherent structures that lend themselves to elegant problem solving methods. Towards this objective efficient parallel algorithms on a class of hypergraphs called acyclic hypergraphs and directed hypergraphs are developed in this thesis. In this thesis, first, the author presents efficient parallel algorithms for the following problems on graphs. (1) Determining whether a graph is strongly chordal, ptolemaic, or a block graph. If the graph is strongly chordal, determine the strongly perfect vertex elimination ordering. (2) Determining the minimal set of edges needed to make an arbitrary graph strong chordal, ptolemaic, or a block graph. (3) Determining the minimum cardinality dominating set, connected dominating set, total dominating set, and the domatic number of a strongly chordal graph. Secondly, he shows that the query implication problem (Q{sub 1} {yields} Q{sub 2}) on two queries, which is to determine whether the data retrieved by query Q{sub 1} is always a subset of the data retrieved by query Q{sub 2}, is not even in NP and in fact complete in {Pi}{sub 2{sup p}}. Thirdly, he develops efficient parallel algorithms for manipulating directed hypergraphs H such as finding a directed path in H, closure of H, and minimum equivalent hypergraph of H. Finally, he also presents an efficient parallel algorithm for multidimensional range search.
Real-time trajectory optimization on parallel processors
NASA Technical Reports Server (NTRS)
Psiaki, Mark L.
1993-01-01
A parallel algorithm has been developed for rapidly solving trajectory optimization problems. The goal of the work has been to develop an algorithm that is suitable to do real-time, on-line optimal guidance through repeated solution of a trajectory optimization problem. The algorithm has been developed on an INTEL iPSC/860 message passing parallel processor. It uses a zero-order-hold discretization of a continuous-time problem and solves the resulting nonlinear programming problem using a custom-designed augmented Lagrangian nonlinear programming algorithm. The algorithm achieves parallelism of function, derivative, and search direction calculations through the principle of domain decomposition applied along the time axis. It has been encoded and tested on 3 example problems, the Goddard problem, the acceleration-limited, planar minimum-time to the origin problem, and a National Aerospace Plane minimum-fuel ascent guidance problem. Execution times as fast as 118 sec of wall clock time have been achieved for a 128-stage Goddard problem solved on 32 processors. A 32-stage minimum-time problem has been solved in 151 sec on 32 processors. A 32-stage National Aerospace Plane problem required 2 hours when solved on 32 processors. A speed-up factor of 7.2 has been achieved by using 32-nodes instead of 1-node to solve a 64-stage Goddard problem.
NASA Astrophysics Data System (ADS)
Cerdeño, D. G.; Peiró, M.; Robles, S.
2015-06-01
We show that the right-handed (RH) sneutrino in the next-to-minimal supersymmetric standard model can account for the observed excess in the Fermi-LAT spectrum of gamma rays from the Galactic center, while fulfilling all the current experimental constraints from the LHC as well as from direct and indirect dark matter searches. We have explored the parameter space of this scenario, computed the gamma-ray spectrum for each phenomenologically viable solution and then performed a ?2 fit to the excess. Unlike previous studies based on model-independent interpretations, we have taken into account the full annihilation spectrum, without assuming pure annihilation channels. Furthermore, we have incorporated limits from direct detection experiments, LHC bounds and also the constraints from Fermi-LAT on dwarf spheroidal galaxies and gamma-ray spectral lines. In addition, we have estimated the effect of the most recent Fermi-LAT reprocessed data (pass 8). In general, we obtain good fits to the Galactic center excess (GCE) when the RH sneutrino annihilates mainly into pairs of light singletlike scalar or pseudoscalar Higgs bosons that subsequently decay in flight, producing four-body final states and spectral features that improve the goodness of the fit at large energies. The best fit (?2=20.8 ) corresponds to a RH sneutrino with a mass of 64 GeV which annihilates preferentially into a pair of light singletlike pseudoscalar Higgs bosons (with masses of order 60 GeV). Besides, we have analyzed other channels that also provide good fits to the excess. Finally, we discuss the implications for direct and indirect detection searches paying special attention to the possible appearance of gamma-ray spectral features in near future Fermi-LAT analyses, as well as deviations from the Standard Model-like Higgs properties at the LHC. Remarkably, many of the scenarios that fit the GCE can also be probed by these other complementary techniques.
Parallel Algorithms for Time and Frequency Domain Circuit Simulation
Dong, Wei
2010-10-12
simulation are the main focuses of our re- search, and correspondingly, the parallel simulation techniques in the following chap- ters are discussed and proposed based on these two analysis methods. B. Time domain analysis: transient simulation 1...
Fast data parallel polygon rendering
Ortega, F.A.; Hansen, C.D.
1993-09-01
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.
The parallel complexity of minimizing column conflicts
John E. Savage; Markus G. Wloka
1992-01-01
Two-layer channel routers typically require a post-processing phase to reduce or eliminate column conflicts. Attempts have been made to parallelize this problem using local search heuristics that swap horizontal channel wire segments. The authors show that all such heuristics for this problem are P-hard and unlikely to be efficiently parallelizable
The Paradyn Parallel Performance Measurement Tool
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
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
Message passing with parallel queue traversal
Underwood, Keith D. (Albuquerque, NM); Brightwell, Ronald B. (Albuquerque, NM); Hemmert, K. Scott (Albuquerque, NM)
2012-05-01
In message passing implementations, associative matching structures are used to permit list entries to be searched in parallel fashion, thereby avoiding the delay of linear list traversal. List management capabilities are provided to support list entry turnover semantics and priority ordering semantics.
Beata Smarzynska Javorcik
Many countries strive to attract foreign direct investment (FDI) in the hope that knowledge brought by multinationals will spill over to domestic industries and increase their productivity. In contrast with earlier literature th at failed to find positive intra-industry spillovers from FDI, this study focuses on effects operating across industries. The analysis, based on a firm-level panel data set from
Beata Smarzynska Javorcik
2004-01-01
Many countries strive to attract foreign direct investment (FDI) hoping that knowledge brought by multinationals will spill over to domestic industries and increase their productivity. In contrast with earlier literature that failed to find positive intraindustry spillovers from FDI, this study focuses on effects operating across industries. The analysis, based on firm-level data from Lithuania, produces evidence consistent with positive
Saleh A. Al-abood; Keith Davids; Simon J. Bennett
2001-01-01
In the present study, the efficacy of visual demonstrations and verbal instructions as instructional constraints on the acquisition of movement coordination was investigated. Fifteen participants performed an aiming task on 100 acquisition and 20 retention trials, under 1 of 3 conditions: a modeling group (MG), a verbally directed group (VDG), and a control group (CG). The MG observed a model
Fuzzy controlled parallel PSO to solving large practical economic dispatch
Belkacem Mahdad; K. Srairi; T. Bouktir; M. El Benbouzid
2010-01-01
This paper proposes a version of fuzzy controlled parallel particle swarm optimization approach based decomposed network (FCP-PSO) to solve large nonconvex economic dispatch problems. The proposed approach combines practical experience extracted from global database formulated in fuzzy rules to adjust dynamically the three parameters associated to PSO mechanism search. The adaptive PSO executed in parallel based in decomposed network procedure
Dataflow Query Execution in a Parallel Main-Memory Environment
Annita N. Wilschut; Peter M. G. Apers
1991-01-01
In this paper, the performance and characteristics of the execution of various join-trees on a parallel DBMS are studied. The results of this study are a step into the direction of the design of a query optimization strategy that is fit for parallel execution of complex queries. Among others, synchronization issues are identified to limit the performance gain from parallelism.
Automatic Management of Parallel and Distributed System Resources
NASA Technical Reports Server (NTRS)
Yan, Jerry; Ngai, Tin Fook; Lundstrom, Stephen F.
1990-01-01
Viewgraphs on automatic management of parallel and distributed system resources are presented. Topics covered include: parallel applications; intelligent management of multiprocessing systems; performance evaluation of parallel architecture; dynamic concurrent programs; compiler-directed system approach; lattice gaseous cellular automata; and sparse matrix Cholesky factorization.
Task Clustering and Scheduling for Distributed Memory Parallel Architectures
Michael A. Palis; Jing-chiou Liou; David S. L. Wei
1996-01-01
This paper addresses the problem of scheduling parallel programs represented as directed acyclic task graphs for execution on distributed memory parallel architectures. Because of the high communication overhead in existing parallel machines, a crucial step in scheduling is task clustering, the process of coalescing fine grain tasks into single coarser ones so that the overall execution time is minimized. The
On Parallelizing Universal Kriging Interpolation Based on OpenMP
Tangpei Cheng; Dandan Li; Qun Wang
2010-01-01
Kriging is one of the important interpolation methods in geostatistics, which has been widely applied in engineering project. In this paper, we present an efficient method for the parallelization of universal Kriging interpolation on shared memory multiprocessors. By using OpenMP directives, we implement a portable parallel algorithm, which enables an incremental approach to add parallelism, without modifying the rest part
Swipp-a multicomputer framework for bulk synchronous parallel computing
O. Sorasen; Yngvar Lundh
1997-01-01
A computer framework feasible for developing parallel systems according to the Bulk Synchronous Parallel (BSP) computing model is described: Switched Interconnection of Parallel Processors (Swipp). Demanding applications can be described as directed graphs where the interdependent subtasks constitute the nodes. The tasks are predistributed by a system master, Computer Executive Engine (GEE), to a set of heterogeneous computing nodes. Each
Computing contingency statistics in parallel.
Bennett, Janine Camille; Thompson, David; Pebay, Philippe Pierre
2010-09-01
Statistical analysis is typically used to reduce the dimensionality of and infer meaning from data. A key challenge of any statistical analysis package aimed at large-scale, distributed data is to address the orthogonal issues of parallel scalability and numerical stability. Many statistical techniques, e.g., descriptive statistics or principal component analysis, are based on moments and co-moments and, using robust online update formulas, can be computed in an embarrassingly parallel manner, amenable to a map-reduce style implementation. In this paper we focus on contingency tables, through which numerous derived statistics such as joint and marginal probability, point-wise mutual information, information entropy, and {chi}{sup 2} independence statistics can be directly obtained. However, contingency tables can become large as data size increases, requiring a correspondingly large amount of communication between processors. This potential increase in communication prevents optimal parallel speedup and is the main difference with moment-based statistics where the amount of inter-processor communication is independent of data size. Here we present the design trade-offs which we made to implement the computation of contingency tables in parallel.We also study the parallel speedup and scalability properties of our open source implementation. In particular, we observe optimal speed-up and scalability when the contingency statistics are used in their appropriate context, namely, when the data input is not quasi-diffuse.
Parallelizing Timed Petri Net simulations
NASA Technical Reports Server (NTRS)
Nicol, David M.
1993-01-01
The possibility of using parallel processing to accelerate the simulation of Timed Petri Nets (TPN's) was studied. It was recognized that complex system development tools often transform system descriptions into TPN's or TPN-like models, which are then simulated to obtain information about system behavior. Viewed this way, it was important that the parallelization of TPN's be as automatic as possible, to admit the possibility of the parallelization being embedded in the system design tool. Later years of the grant were devoted to examining the problem of joint performance and reliability analysis, to explore whether both types of analysis could be accomplished within a single framework. In this final report, the results of our studies are summarized. We believe that the problem of parallelizing TPN's automatically for MIMD architectures has been almost completely solved for a large and important class of problems. Our initial investigations into joint performance/reliability analysis are two-fold; it was shown that Monte Carlo simulation, with importance sampling, offers promise of joint analysis in the context of a single tool, and methods for the parallel simulation of general Continuous Time Markov Chains, a model framework within which joint performance/reliability models can be cast, were developed. However, very much more work is needed to determine the scope and generality of these approaches. The results obtained in our two studies, future directions for this type of work, and a list of publications are included.
NASA Astrophysics Data System (ADS)
Fox Machado, L.; Michel, R.; Alvarez, M.; Peña, J. H.
2015-01-01
We report the results of CCD photometric observations in the direction of the Coma Berenices and Upgren 1 open clusters with the aim at searching for new short-period variable stars. A total of 35 stars were checked for variability. As a result of this search the star designated in the SIMBAD database as Melotte 111 AV 1224 was found to be a new eclipsing binary star. Follow-up Strömgren photometric and spectroscopic observations allowed us to derive the spectral type, distance, reddening and effective temperature of the star. A preliminary analysis of the binary light curve was performed and the parameters of the orbital system were derived. From the derived physical parameters we conclude that Melotte 111 AV 1224 is most likely a W-UMa eclipsing binary that is not a member of the Coma Berenices open cluster. On other hand, we did not find evidence of brightness variations in the stars NSV 5612 and NSV 5615 previously catalogued as variable stars in Coma Berenices open cluster.
NASA Astrophysics Data System (ADS)
Dmtpc Collaboration; Ahlen, S.; Battat, J. B. R.; Caldwell, T.; Deaconu, C.; Dujmic, D.; Fedus, W.; Fisher, P.; Golub, F.; Henderson, S.; Inglis, A.; Kaboth, A.; Kohse, G.; Lanza, R.; Lee, A.; Lopez, J.; Monroe, J.; Sahin, T.; Sciolla, G.; Skvorodnev, N.; Tomita, H.; Wellenstein, H.; Wolfe, I.; Yamamoto, R.; Yegoryan, H.
2011-01-01
The Dark Matter Time Projection Chamber (DMTPC) is a low pressure (75 Torr CF4) 10 liter detector capable of measuring the vector direction of nuclear recoils with the goal of directional dark matter detection. In this Letter we present the first dark matter limit from DMTPC from a surface run at MIT. In an analysis window of 80-200 keV recoil energy, based on a 35.7 g-day exposure, we set a 90% C.L. upper limit on the spin-dependent WIMP-proton cross section of 2.0×10-33 cm2 for 115 GeV/c2 dark matter particle mass.
NASA Astrophysics Data System (ADS)
Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Bacci, C.; Beltrame, P.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocchetta, S.; Bossi, F.; Branchini, P.; Caloi, R.; Campana, P.; Capon, G.; Capussela, T.; Ceradini, F.; Cesario, F.; Chi, S.; Chiefari, G.; Ciambrone, P.; Crucianelli, F.; De Lucia, E.; de Santis, A.; de Simone, P.; de Zorzi, G.; Denig, A.; di Domenico, A.; di Donato, C.; di Micco, B.; Doria, A.; Dreucci, M.; Felici, G.; Ferrari, A.; Ferrer, M. L.; Fiore, S.; Forti, C.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Gorini, E.; Graziani, E.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Leone, D.; Martini, M.; Massarotti, P.; Mei, W.; Meola, S.; Miscetti, S.; Moulson, M.; Müller, S.; Murtas, F.; Napolitano, M.; Nguyen, F.; Palutan, M.; Pasqualucci, E.; Passeri, A.; Patera, V.; Perfetto, F.; Primavera, M.; Santangelo, P.; Saracino, G.; Sciascia, B.; Sciubba, A.; Sibidanov, A.; Spadaro, T.; Testa, M.; Tortora, L.; Valente, P.; Venanzoni, G.; Versaci, R.; Xu, G.
2008-06-01
We present a measurement of the ratio R=?(K0 e3?;E* ? > 30 MeV, ?* ?>20°)/?(K0 e3) and a first measurement of the direct emission contribution in semileptonic KL decays. The measurement was performed at the DA NE ? factory by selecting ??KLKS decays with the KLOE detector. We use 328 pb-1 of data, corresponding to about 3.5 million K0 e3 events and about 9000 K0 e3? radiative events. Our result is R=(924±23stat±16syst)×10-5 for the branching ratio and
Search for a Direct Large-Cluster-Transfer Process in the C-12,c-13(ne-20,a) Reaction
Murakami, T.; Takahashi, N.; Lui, YW; Takada, E.; Tanner, D. M.; Tribble, Robert E.; Ungricht, E.; Nagatani, K.
1985-01-01
initiated by the exper- imental discovery of broad peaks in the continuum region of the '2C('60, o.) reaction. ' Since the excitation energies of those peaks were closely correlated to energies of the ' C+' C intermediate, or nuclear molecular resonances... of a ONe nucleus has a strong n-'60 clustering strength. Therefore, a Ne induced reaction might have appreciable amount of a direct '60 transfer process. The ' C+' 0 system is generally accepted to have intermediate-structure resonances and has been...
Speculative parallelization of partially parallel loops
Dang, Francis Hoai Dinh
2009-05-15
, and applied a fully parallel data dependence test to determine if it had any cross–processor depen- dences. If the test failed, then the loop was re–executed serially. While this method exploits doall parallelism well, it can cause slowdowns for loops...
NSDL National Science Digital Library
Amy Apon
* 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
Parallel algorithm for dominant points correspondences in robot binocular stereo vision
NASA Technical Reports Server (NTRS)
Al-Tammami, A.; Singh, B.
1993-01-01
This paper presents an algorithm to find the correspondences of points representing dominant feature in robot stereo vision. The algorithm consists of two main steps: dominant point extraction and dominant point matching. In the feature extraction phase, the algorithm utilizes the widely used Moravec Interest Operator and two other operators: the Prewitt Operator and a new operator called Gradient Angle Variance Operator. The Interest Operator in the Moravec algorithm was used to exclude featureless areas and simple edges which are oriented in the vertical, horizontal, and two diagonals. It was incorrectly detecting points on edges which are not on the four main directions (vertical, horizontal, and two diagonals). The new algorithm uses the Prewitt operator to exclude featureless areas, so that the Interest Operator is applied only on the edges to exclude simple edges and to leave interesting points. This modification speeds-up the extraction process by approximately 5 times. The Gradient Angle Variance (GAV), an operator which calculates the variance of the gradient angle in a window around the point under concern, is then applied on the interesting points to exclude the redundant ones and leave the actual dominant ones. The matching phase is performed after the extraction of the dominant points in both stereo images. The matching starts with dominant points in the left image and does a local search, looking for corresponding dominant points in the right image. The search is geometrically constrained the epipolar line of the parallel-axes stereo geometry and the maximum disparity of the application environment. If one dominant point in the right image lies in the search areas, then it is the corresponding point of the reference dominant point in the left image. A parameter provided by the GAV is thresholded and used as a rough similarity measure to select the corresponding dominant point if there is more than one point the search area. The correlation is used as a final decision tool when there is still more than one point in the search area. If there is no dominant point in the search area of if the points in the search area are below a correlation threshold, then the dominant point in the reference image is occluded and can not be corresponded. The algorithm has been modeled, implemented and shown to be fast, robust and parallel. The parallelism is created from three main features: locality of the operators; a memory optimization scheme; and the ability to fully parallelize the extraction phase which is the most computational intensive task in the algorithm. The last feature is achieved by performing the extraction phase on the two images simultaneously.
Parallel flow diffusion battery
Yeh, H.C.; Cheng, Y.S.
1984-01-01
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.
Parallel flow diffusion battery
Yeh, Hsu-Chi (Albuquerque, NM); Cheng, Yung-Sung (Albuquerque, NM)
1984-08-07
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.
DC Circuits: Parallel Resistances
NSDL National Science Digital Library
In this interactive learning activity, students will learn about parallel circuits. They will measure and calculate the resistance of parallel circuits and answer several questions about the example circuit shown.
Learning in Parallel Universes
Michael R. Berthold; Bernd Wiswedel
2007-01-01
This abstract summarizes a brief, preliminary formalization of learning in parallel universes. It also attempts to highlight a few neigh- boring learning paradigms to illustrate how parallel learning ts into the greater picture.
Introduction to parallel programming
Brawer, S. (Encore Computer Corp., Marlborough, MA (US))
1989-01-01
This book describes parallel programming and all the basic concepts illustrated by examples in a simplified FORTRAN. Concepts covered include: The parallel programming model; The creation of multiple processes; Memory sharing; Scheduling; Data dependencies. In addition, a number of parallelized applications are presented, including a discrete-time, discrete-event simulator, numerical integration, Gaussian elimination, and parallelized versions of the traveling salesman problem and the exploration of a maze.
Fan, W.C.; Halbleib, J.A. Sr.
1996-09-01
This report provides a users` guide for parallel processing ITS on a UNIX workstation network, a shared-memory multiprocessor or a massively-parallel processor. The parallelized version of ITS is based on a master/slave model with message passing. Parallel issues such as random number generation, load balancing, and communication software are briefly discussed. Timing results for example problems are presented for demonstration purposes.
On the Scalability of Parallel UCT
NASA Astrophysics Data System (ADS)
Segal, Richard B.
The parallelization of MCTS across multiple-machines has proven surprisingly difficult. The limitations of existing algorithms were evident in the 2009 Computer Olympiad where Zen using a single four-core machine defeated both Fuego with ten eight-core machines, and Mogo with twenty thirty-two core machines. This paper investigates the limits of parallel MCTS in order to understand why distributed parallelism has proven so difficult and to pave the way towards future distributed algorithms with better scaling. We first analyze the single-threaded scaling of Fuego and find that there is an upper bound on the play-quality improvements which can come from additional search. We then analyze the scaling of an idealized N-core shared memory machine to determine the maximum amount of parallelism supported by MCTS. We show that parallel speedup depends critically on how much time is given to each player. We use this relationship to predict parallel scaling for time scales beyond what can be empirically evaluated due to the immense computation required. Our results show that MCTS can scale nearly perfectly to at least 64 threads when combined with virtual loss, but without virtual loss scaling is limited to just eight threads. We also find that for competition time controls scaling to thousands of threads is impossible not necessarily due to MCTS not scaling, but because high levels of parallelism can start to bump up against the upper performance bound of Fuego itself.
Circuit Optimization Using Efficient Parallel Pattern Search
Narasimhan, Srinath S.
2011-08-08
challenging task to optimize the entire system considering all block level trade-offs. In this work, we address these two challenging optimization problems i.e.; clock mesh skew optimization and PLL locking time reduction. The expensive objective function...
Pthreads for Dynamic Parallelism
Girija J. Narlikar; Guy E. Blelloch
1998-01-01
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
ERIC Educational Resources Information Center
Fahnestock, Jeanne
2003-01-01
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…
Karen A. Frenkel
1986-01-01
The articles presented in our Special Issue on parallel processing on the supercomputing scale reflect, to some extent, splits in the community developing these machines. There are several schools of thought on how best to implement parallel processing at both the hard- and software levels. Controversy exists over the wisdom of aiming for general- or special-purpose parallel machines, and what
Vergados, J. D. [University of Ioannina, Ioannina, GR 45110 (Greece)], E-mail: vergados@cc.uoi.gr
2009-07-15
In this paper, we obtain the weakly interacting, massive particle (WIMP) velocity distribution in our vicinity starting from spherically symmetric WIMP density profiles in a self-consistent way by employing the Eddington approach. By adding a reasonable angular-momentum-dependent term in the expression of the energy, we obtain axially symmetric WIMP velocity distributions as well. We find that some density profiles lead to approximate Maxwell-Boltzmann distributions, which are automatically defined in a finite domain, i.e., the escape velocity need not be put by hand. The role of such distributions in obtaining the direct WIMP detection rates, including the modulation, is studied in some detail and, in particular, the role of the asymmetry is explored.
PARASPICE: A Parallel Circuit Simulator for Shared-Memory Multiprocessors
Gung-chung Yang
1990-01-01
This paper presents a general approach to parallelizing direct method circuit simulation. The approach extracts parallel tasks at the algorithmic level for each compute-intensive module and therefore is suitable for a wide range of shared-memory multiprocessors. The implementation of the approach in SPICE2 resulted in a portable parallel direct circuit simulator, PARASPICE. The superior performance of PARASPICE is demonstrated on
Parallel Cholesky-based reduction for the weighted integer least squares problem
NASA Astrophysics Data System (ADS)
Xu, Peiliang
2012-01-01
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.
Parallel Imaging Microfluidic Cytometer
Ehrlich, Daniel J.; McKenna, Brian K.; Evans, James G.; Belkina, Anna C.; Denis, Gerald V.; Sherr, David; Cheung, Man Ching
2011-01-01
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. PMID:21704835
Parallel Atomistic Simulations
HEFFELFINGER,GRANT S.
2000-01-18
Algorithms developed to enable the use of atomistic molecular simulation methods with parallel computers are reviewed. Methods appropriate for bonded as well as non-bonded (and charged) interactions are included. While strategies for obtaining parallel molecular simulations have been developed for the full variety of atomistic simulation methods, molecular dynamics and Monte Carlo have received the most attention. Three main types of parallel molecular dynamics simulations have been developed, the replicated data decomposition, the spatial decomposition, and the force decomposition. For Monte Carlo simulations, parallel algorithms have been developed which can be divided into two categories, those which require a modified Markov chain and those which do not. Parallel algorithms developed for other simulation methods such as Gibbs ensemble Monte Carlo, grand canonical molecular dynamics, and Monte Carlo methods for protein structure determination are also reviewed and issues such as how to measure parallel efficiency, especially in the case of parallel Monte Carlo algorithms with modified Markov chains are discussed.
Agis-Torres, Angel; Sölhuber, Monica; Fernandez, Maria; Sanchez-Montero, J.M.
2014-01-01
The lack of an adequate therapy for Alzheimer's Disease (AD) contributes greatly to the continuous growing amount of papers and reviews, reflecting the important efforts made by scientists in this field. It is well known that AD is the most common cause of dementia, and up-to-date there is no prevention therapy and no cure for the disease, which contrasts with the enormous efforts put on the task. On the other hand many aspects of AD are currently debated or even unknown. This review offers a view of the current state of knowledge about AD which includes more relevant findings and processes that take part in the disease; it also shows more relevant past, present and future research on therapeutic drugs taking into account the new paradigm “Multi-Target-Directed Ligands” (MTDLs). In our opinion, this paradigm will lead from now on the research toward the discovery of better therapeutic solutions, not only in the case of AD but also in other complex diseases. This review highlights the strategies followed by now, and focuses other emerging targets that should be taken into account for the future development of new MTDLs. Thus, the path followed in this review goes from the pathology and the processes involved in AD to the strategies to consider in on-going and future researches. PMID:24533013
Taylor, Frank E.
The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1 fb?1 of proton-proton collision data at s? = 8 TeV recorded with the ATLAS detector at the ...
Taylor, Frank E.
A search for the direct production of charginos and neutralinos in final states with three leptons and missing transverse momentum is presented. The analysis is based on 20.3 fb[superscript ?1] of s? = 8 TeV proton-proton ...
Taylor, Frank E.
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[superscript -1] of ?s = 7 TeV ...
GPU Computing with OpenACC Directives
Crawford, T. Daniel
, with low-level access ! Compiler directives to specify parallel regions in C, C++, Fortran ! Open Languages OpenACC Directives Maximum Flexibility Easily Accelerate Applications #12;OpenACC Directives access to the massive parallel power of a GPU OpenACC The Standard for GPU Directives #12;High-level
Wright, Kynna; Giger, Joyce Newman; Norris, Keth; Suro, Zulma
2013-01-01
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. PMID:23021318
NASA Astrophysics Data System (ADS)
Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmad, A.; Ahmadov, F.; Aielli, G.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Gonzalez, B. Alvarez; Alviggi, M. G.; Amako, K.; Coutinho, Y. Amaral; Amelung, C.; Amidei, D.; Ammosov, V. V.; Santos, S. P. Amor Dos; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Bella, L. Aperio; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Backus Mayes, J.; Badescu, E.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, S.; Balek, P.; Balli, F.; Banas, E.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bannoura, A. A. E.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Bartsch, V.; Bassalat, A.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, K.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belloni, A.; Beloborodova, O. L.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernard, C.; Bernat, P.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Bessidskaia, O.; Besson, N.; Betancourt, C.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; De Mendizabal, J. Bilbao; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boek, T. T.; Bogaerts, J. A.; Bogdanchikov, A. G.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borri, M.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutouil, S.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Brendlinger, K.; Brennan, A. J.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, G.; Brown, J.; de Renstrom, P. A. Bruckman; Bruncko, D.; Bruneliere, R.
2014-06-01
A search is presented for direct top-squark pair production in final states with two leptons (electrons or muons) of opposite charge using 20.3 fb-1 of pp collision data at = 8 TeV, collected by the ATLAS experiment at the Large Hadron Collider in 2012. No excess over the Standard Model expectation is found. The results are interpreted under the separate assumptions (i) that the top squark decays to a b-quark in addition to an on-shell chargino whose decay occurs via a real or virtual W boson, or (ii) that the top squark decays to a t-quark and the lightest neutralino. A top squark with a mass between 150 GeV and 445 GeV decaying to a b-quark and an on-shell chargino is excluded at 95% confidence level for a top squark mass equal to the chargino mass plus 10 GeV, in the case of a 1 GeV lightest neutralino. Top squarks with masses between 215 (90) GeV and 530 (170) GeV decaying to an on-shell (off-shell) t-quark and a neutralino are excluded at 95% confidence level for a 1 GeV neutralino. [Figure not available: see fulltext.
PDDP: A data parallel programming model. Revision 1
Warren, K.H.
1995-06-01
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.
Quantum Search in Hilbert Space
NASA Technical Reports Server (NTRS)
Zak, Michail
2003-01-01
A proposed quantum-computing algorithm would perform a search for an item of information in a database stored in a Hilbert-space memory structure. The algorithm is intended to make it possible to search relatively quickly through a large database under conditions in which available computing resources would otherwise be considered inadequate to perform such a task. The algorithm would apply, more specifically, to a relational database in which information would be stored in a set of N complex orthonormal vectors, each of N dimensions (where N can be exponentially large). Each vector would constitute one row of a unitary matrix, from which one would derive the Hamiltonian operator (and hence the evolutionary operator) of a quantum system. In other words, all the stored information would be mapped onto a unitary operator acting on a quantum state that would represent the item of information to be retrieved. Then one could exploit quantum parallelism: one could pose all search queries simultaneously by performing a quantum measurement on the system. In so doing, one would effectively solve the search problem in one computational step. One could exploit the direct- and inner-product decomposability of the unitary matrix to make the dimensionality of the memory space exponentially large by use of only linear resources. However, inasmuch as the necessary preprocessing (the mapping of the stored information into a Hilbert space) could be exponentially expensive, the proposed algorithm would likely be most beneficial in applications in which the resources available for preprocessing were much greater than those available for searching.
Parallel Plate System for Collecting Data Used to Determine Viscosity
NASA Technical Reports Server (NTRS)
Kaukler, William (Inventor); Ethridge, Edwin C. (Inventor)
2013-01-01
A parallel-plate system collects data used to determine viscosity. A first plate is coupled to a translator so that the first plate can be moved along a first direction. A second plate has a pendulum device coupled thereto such that the second plate is suspended above and parallel to the first plate. The pendulum device constrains movement of the second plate to a second direction that is aligned with the first direction and is substantially parallel thereto. A force measuring device is coupled to the second plate for measuring force along the second direction caused by movement of the second plate.
Deshmane, Anagha; Gulani, Vikas; Griswold, Mark A.; Seiberlich, Nicole
2015-01-01
Parallel imaging is a robust method for accelerating the acquisition of magnetic resonance imaging (MRI) data, and has made possible many new applications of MR imaging. Parallel imaging works by acquiring a reduced amount of k-space data with an array of receiver coils. These undersampled data can be acquired more quickly, but the undersampling leads to aliased images. One of several parallel imaging algorithms can then be used to reconstruct artifact-free images from either the aliased images (SENSE-type reconstruction) or from the under-sampled data (GRAPPA-type reconstruction). The advantages of parallel imaging in a clinical setting include faster image acquisition, which can be used, for instance, to shorten breath-hold times resulting in fewer motion-corrupted examinations. In this article the basic concepts behind parallel imaging are introduced. The relationship between undersampling and aliasing is discussed and two commonly used parallel imaging methods, SENSE and GRAPPA, are explained in detail. Examples of artifacts arising from parallel imaging are shown and ways to detect and mitigate these artifacts are described. Finally, several current applications of parallel imaging are presented and recent advancements and promising research in parallel imaging are briefly reviewed. PMID:22696125
Kinosita Jr., Kazuhiko
Advanced Search Search Tips Advanced Search Search Tips springerlink.com SpringerLink 2,000 40 Search Tips CONTENT DOI CITATION DOI ISSN ISBN CATEGORY AND DATE LIMITERS Journals Books ProtocolsPress ID Save this Item Saved Item Name MY SPRINGERLINK Pay-per-View 5. http
The psychophysics of visual search
John Palmer; Preeti Verghese; Misha Pavel
2000-01-01
Most theories of visual search emphasize issues of limited versus unlimited capacity and serial versus parallel processing. In the present article, we suggest a broader framework based on two principles, one empirical and one theoretical. The empirical principle is to focus on conditions at the intersection of visual search and the simple detection and discrimination paradigms of spatial vision. Such
Parallel symbolic computation in ACE
Enrico Pontelli; Gopal Gupta
1997-01-01
We present an overview of the ACE system, a sound and complete parallel implementation of Prolog that exploits parallelism\\u000a transparently (i.e., without any user intervention) from AI programs and symbolic applications coded in Prolog. ACE simultaneously\\u000a exploits all the major forms of parallelism – Or-parallelism, Independent And-parallelism, and Dependent And-parallelism –\\u000a found in Prolog programs. These three varieties of parallelism
The Paradyn parallel performance measurement tools
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
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.
Parallel Algorithms for Reducible Flow Graphs
Vijaya Ramachandran
1997-01-01
We present parallel NC algorithms for recognizing a reducible flow graph (rfg) and for finding dominators, minimum feedback vertex sets, and a depth first search tree in an rfg. On ann-node rfg, all of these algorithms run inpolylog(n) time usingM(n) processors, whereM(n) is the number of processors needed to multiply twon×nmatrices in polylog time. We show that finding a minimum
Code Parallelization with CAPO: A User Manual
NASA Technical Reports Server (NTRS)
Jin, Hao-Qiang; Frumkin, Michael; Yan, Jerry; Biegel, Bryan (Technical Monitor)
2001-01-01
A software tool has been developed to assist the parallelization of scientific codes. This tool, CAPO, extends an existing parallelization toolkit, CAPTools developed at the University of Greenwich, to generate OpenMP parallel codes for shared memory architectures. This is an interactive toolkit to transform a serial Fortran application code to an equivalent parallel version of the software - in a small fraction of the time normally required for a manual parallelization. We first discuss the way in which loop types are categorized and how efficient OpenMP directives can be defined and inserted into the existing code using the in-depth interprocedural analysis. The use of the toolkit on a number of application codes ranging from benchmark to real-world application codes is presented. This will demonstrate the great potential of using the toolkit to quickly parallelize serial programs as well as the good performance achievable on a large number of toolkit to quickly parallelize serial programs as well as the good performance achievable on a large number of processors. The second part of the document gives references to the parameters and the graphic user interface implemented in the toolkit. Finally a set of tutorials is included for hands-on experiences with this toolkit.
Parallel Programming and Parallel Abstractions in Fortress
Guy L. Steele Jr.
2005-01-01
Summary form only given. The Programming Language Research Group at Sun Microsystems Laboratories seeks to apply lessons learned from the Java (TM) programming language to the next generation of programming languages. The Java language supports platform-independent parallel programming with explicit multithreading and explicit locks. As part of the DARPA program for High Productivity Computing Systems, we are developing Fortress, a
Highly scalable parallel sorting
Edgar Solomonik; Laxmikant V. Kalé
2010-01-01
Sorting is a commonly used process with a wide breadth of applications in the high performance computing field. Early research in parallel processing has provided us with comprehensive analysis and theory for parallel sorting algorithms. However, modern super- computers have advanced rapidly in size and changed significantly in architecture, forcing new adaptations to these algorithms. To fully utilize the potential
Weening, J.S.
1988-05-01
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 describes the structure of the simulator, measures its performance, and gives an example of its use with a parallel Lisp program.
D. Bailey; E. Barszcz; J. Barton; D. Browning; R. Carter; L. Dagum
1994-01-01
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
Parallelizing quantum circuits
Anne Broadbent; Elham Kashefi
2009-01-01
We present a novel automated technique for parallelizing quantum circuits via forward and backward translation to measurement-based quantum computing patterns and analyze the trade off in terms of depth and space complexity. As a result we distinguish a class of polynomial depth circuits that can be parallelized to logarithmic depth while adding only polynomial many auxiliary qubits. In particular, we
Parallelization of thermochemical nanolithography.
Carroll, Keith M; Lu, Xi; Kim, Suenne; Gao, Yang; Kim, Hoe-Joon; Somnath, Suhas; Polloni, Laura; Sordan, Roman; King, William P; Curtis, Jennifer E; Riedo, Elisa
2014-01-01
One of the most pressing technological challenges in the development of next generation nanoscale devices is the rapid, parallel, precise and robust fabrication of nanostructures. Here, we demonstrate the possibility to parallelize thermochemical nanolithography (TCNL) by employing five nano-tips for the fabrication of conjugated polymer nanostructures and graphene-based nanoribbons. PMID:24337109
Performance Evaluation in Network-Based Parallel Computing
NASA Technical Reports Server (NTRS)
Dezhgosha, Kamyar
1996-01-01
Network-based parallel computing is emerging as a cost-effective alternative for solving many problems which require use of supercomputers or massively parallel computers. The primary objective of this project has been to conduct experimental research on performance evaluation for clustered parallel computing. First, a testbed was established by augmenting our existing SUNSPARCs' network with PVM (Parallel Virtual Machine) which is a software system for linking clusters of machines. Second, a set of three basic applications were selected. The applications consist of a parallel search, a parallel sort, a parallel matrix multiplication. These application programs were implemented in C programming language under PVM. Third, we conducted performance evaluation under various configurations and problem sizes. Alternative parallel computing models and workload allocations for application programs were explored. The performance metric was limited to elapsed time or response time which in the context of parallel computing can be expressed in terms of speedup. The results reveal that the overhead of communication latency between processes in many cases is the restricting factor to performance. That is, coarse-grain parallelism which requires less frequent communication between processes will result in higher performance in network-based computing. Finally, we are in the final stages of installing an Asynchronous Transfer Mode (ATM) switch and four ATM interfaces (each 155 Mbps) which will allow us to extend our study to newer applications, performance metrics, and configurations.
Massively parallel mathematical sieves
Montry, G.R.
1989-01-01
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.
NASA Technical Reports Server (NTRS)
Khanna, S. M.; Urban, E. W. (inventors)
1979-01-01
A direct current transformer in which the primary consists of an elongated strip of superconductive material, across the ends of which is direct current potential is described. Parallel and closely spaced to the primary is positioned a transformer secondary consisting of a thin strip of magnetoresistive material.
Rowe, Will; Baker, Kate S.; Verner-Jeffreys, David; Baker-Austin, Craig; Ryan, Jim J.; Maskell, Duncan; Pearce, Gareth
2015-01-01
Background Antimicrobial resistance remains a growing and significant concern in human and veterinary medicine. Current laboratory methods for the detection and surveillance of antimicrobial resistant bacteria are limited in their effectiveness and scope. With the rapidly developing field of whole genome sequencing beginning to be utilised in clinical practice, the ability to interrogate sequencing data quickly and easily for the presence of antimicrobial resistance genes will become increasingly important and useful for informing clinical decisions. Additionally, use of such tools will provide insight into the dynamics of antimicrobial resistance genes in metagenomic samples such as those used in environmental monitoring. Results Here we present the Search Engine for Antimicrobial Resistance (SEAR), a pipeline and web interface for detection of horizontally acquired antimicrobial resistance genes in raw sequencing data. The pipeline provides gene information, abundance estimation and the reconstructed sequence of antimicrobial resistance genes; it also provides web links to additional information on each gene. The pipeline utilises clustering and read mapping to annotate full-length genes relative to a user-defined database. It also uses local alignment of annotated genes to a range of online databases to provide additional information. We demonstrate SEAR’s application in the detection and abundance estimation of antimicrobial resistance genes in two novel environmental metagenomes, 32 human faecal microbiome datasets and 126 clinical isolates of Shigella sonnei. Conclusions We have developed a pipeline that contributes to the improved capacity for antimicrobial resistance detection afforded by next generation sequencing technologies, allowing for rapid detection of antimicrobial resistance genes directly from sequencing data. SEAR uses raw sequencing data via an intuitive interface so can be run rapidly without requiring advanced bioinformatic skills or resources. Finally, we show that SEAR is effective in detecting antimicrobial resistance genes in metagenomic and isolate sequencing data from both environmental metagenomes and sequencing data from clinical isolates. PMID:26197475
Dataflow Query Execution in a Parallel, Main-memory Environment
Annita N. Wilschut; P. M. G. Apers
1993-01-01
In this paper, the performance and characteristics of the execution of various join-trees on a parallel DBMS are studied. The results of this study are a step into the direction of the design of a query optimization strategy that is fit for parallel execution of complex queries.\\u000aAmong others, synchronization issues are identified to limit the performance gain from parallelism.
Parallel transistor level circuit simulation using domain decomposition methods
He Peng; Chung-kuan Cheng
2009-01-01
This paper presents an efficient parallel transistor level full-chip circuit simulation tool with SPICE-accuracy. The new approach partitions the circuit into a linear domain and several non-linear domains based on circuit non-linearity and connectivity. The linear domain is solved by parallel fast linear solver while nonlinear domains are parallelly distributed into different processors and solved by direct solver. Parallel domain
Parafrase restructuring of FORTRAN code for parallel processing
NASA Technical Reports Server (NTRS)
Wadhwa, Atul
1988-01-01
Parafrase transforms a FORTRAN code, subroutine by subroutine, into a parallel code for a vector and/or shared-memory multiprocessor system. Parafrase is not a compiler; it transforms a code and provides information for a vector or concurrent process. Parafrase uses a data dependency to reveal parallelism among instructions. The data dependency test distinguishes between recurrences and statements that can be directly vectorized or parallelized. A number of transformations are required to build a data dependency graph.
Application of a parallel DSMC method to hypersonic rarefied flows
Wilmoth, R.G. (NASA, Langley Research Center, Hampton, VA (USA))
1991-01-01
This paper describes a method for doing direct simulation Monte Carlo (DSMC) calculations using parallel processing and presents some results of applying the method to several hypersonic, rarefied flow problems. The performance and efficiency of the parallel method are discussed. The applications described are the flow in a channel and the flow about a flat plate at incidence. The results show significant advantages of parallel processing over conventional scalar processing and demonstrate the scalability of the method to large problems. 8 refs.
Bilingual parallel programming
Foster, I.; Overbeek, R.
1990-01-01
Numerous experiments have demonstrated that computationally intensive algorithms support adequate parallelism to exploit the potential of large parallel machines. Yet successful parallel implementations of serious applications are rare. The limiting factor is clearly programming technology. None of the approaches to parallel programming that have been proposed to date -- whether parallelizing compilers, language extensions, or new concurrent languages -- seem to adequately address the central problems of portability, expressiveness, efficiency, and compatibility with existing software. In this paper, we advocate an alternative approach to parallel programming based on what we call bilingual programming. We present evidence that this approach provides and effective solution to parallel programming problems. The key idea in bilingual programming is to construct the upper levels of applications in a high-level language while coding selected low-level components in low-level languages. This approach permits the advantages of a high-level notation (expressiveness, elegance, conciseness) to be obtained without the cost in performance normally associated with high-level approaches. In addition, it provides a natural framework for reusing existing code.
Simulating Billion-Task Parallel Programs
Perumalla, Kalyan S [ORNL] [ORNL; Park, Alfred J [ORNL] [ORNL
2014-01-01
In simulating large parallel systems, bottom-up approaches exercise detailed hardware models with effects from simplified software models or traces, whereas top-down approaches evaluate the timing and functionality of detailed software models over coarse hardware models. Here, we focus on the top-down approach and significantly advance the scale of the simulated parallel programs. Via the direct execution technique combined with parallel discrete event simulation, we stretch the limits of the top-down approach by simulating message passing interface (MPI) programs with millions of tasks. Using a timing-validated benchmark application, a proof-of-concept scaling level is achieved to over 0.22 billion virtual MPI processes on 216,000 cores of a Cray XT5 supercomputer, representing one of the largest direct execution simulations to date, combined with a multiplexing ratio of 1024 simulated tasks per real task.
Parallelization for geophysical waveform analysis
Kurth, Derek Edward
2013-02-22
&M University to aid the parallel programmer by providing standard implementations of common parallel programming tasks. Our research involves using STAPL to apply parallel methods to a problem that has already been solved sequentially: Seismic ray tracing...
Parallel Programming and Parallel Abstractions in Fortress
Guy L. Steele Jr.
2006-01-01
\\u000a The Programming Language Research Group at Sun Microsystems Laboratories seeks to apply lessons learned from the Java (TM)\\u000a Programming Language to the next generation of programming languages. The Java language supports platform-independent parallel\\u000a programming with explicit multithreading and explicit locks. As part of the DARPA program for High Productivity Computing\\u000a Systems, we are developing Fortress, a language intended to support
PARALLEL IMPLEMENTATION OF VLSI HED CIRCUIT SIMULATION
Silc, Jurij
14 PARALLEL IMPLEMENTATION OF VLSI HED CIRCUIT SIMULATION INFORMATICA 2/91 Keywords: circuit, India Junj Sile Marjan Spegel Jozef Stefan Institute, Ljubljana, Slovenia The importance of circuit simulation in the design of VLSI circuits has channelised research work in the direction of finding methods
A Parallel VLSI Circuit Layout Methodology
S. Bapat; James P. Cohoon
1993-01-01
We propose a parallel computation layout technique that solves the layout problem directly rather than decomposing it into the traditional distinct steps of placement and routing. The method combines a superior geometric partitioning algorithm with extensive use of pre-computed minimum-length Steiner trees to produce layouts.
NSDL National Science Digital Library
2013-08-30
In this activity, learners demonstrate and discuss simple circuits as well as the differences between parallel and serial circuit design and functions. Learners test two different circuit designs through the use of low voltage light bulbs.
Parallelization of thermochemical nanolithography
NASA Astrophysics Data System (ADS)
Carroll, Keith M.; Lu, Xi; Kim, Suenne; Gao, Yang; Kim, Hoe-Joon; Somnath, Suhas; Polloni, Laura; Sordan, Roman; King, William P.; Curtis, Jennifer E.; Riedo, Elisa
2014-01-01
One of the most pressing technological challenges in the development of next generation nanoscale devices is the rapid, parallel, precise and robust fabrication of nanostructures. Here, we demonstrate the possibility to parallelize thermochemical nanolithography (TCNL) by employing five nano-tips for the fabrication of conjugated polymer nanostructures and graphene-based nanoribbons.One of the most pressing technological challenges in the development of next generation nanoscale devices is the rapid, parallel, precise and robust fabrication of nanostructures. Here, we demonstrate the possibility to parallelize thermochemical nanolithography (TCNL) by employing five nano-tips for the fabrication of conjugated polymer nanostructures and graphene-based nanoribbons. Electronic supplementary information (ESI) available: Details on the cantilevers array, on the sample preparation, and on the GO AFM experiments. See DOI: 10.1039/c3nr05696a
ERIC Educational Resources Information Center
Rogers, Pat
1972-01-01
Criteria for a reasonable axiomatic system are discussed. A discussion of the historical attempts to prove the independence of Euclids parallel postulate introduces non-Euclidean geometries. Poincare's model for a non-Euclidean geometry is defined and analyzed. (LS)
On the Parallel kth Extension of the Sieve of Eratosthenes
K. Liszka; A. Quesada
1996-01-01
The Sieve of Eratosthenes has been recently extended by excluding, for a given k the multiples of the first k primes from the initial set. The approach developed lends itself nicely to massive parallelism. Four data layouts are presented for a massively parallel SIMD architecture. It is shown that the mapping of data directly affects the performance of the algorithm.
CUDA-Accelerated ODETLAP: A Parallel Lossy Compression Implementation
Franklin, W. Randolph
CUDA-Accelerated ODETLAP: A Parallel Lossy Compression Implementation [Extended Abstract] Daniel N Laplacian Partial Differentiation Equations (ODETLAP) that uses CUDA directly. This lossy compression, correlated data. ODETLAP can be used to compress a dataset or to reconstruct missing data. Parallelism
Breakdown of Spatial Parallel Coding in Children's Drawing
ERIC Educational Resources Information Center
De Bruyn, Bart; Davis, Alyson
2005-01-01
When drawing real scenes or copying simple geometric figures young children are highly sensitive to parallel cues and use them effectively. However, this sensitivity can break down in surprisingly simple tasks such as copying a single line where robust directional errors occur despite the presence of parallel cues. Before we can conclude that this…
Parallel plate THz transmitter S. Coleman and D. Grischkowskya)
Parallel plate THz transmitter S. Coleman and D. Grischkowskya) School of Electrical and Computer December 2003 A THz transmitter that directly excites the guided wave modes of a dielectric filled parallel plate waveguide is demonstrated. When coupled to free space, the transmitter yields a large peak time
Rachel Cooke; Rebecca Donlan
2008-01-01
In a comparison of Google Scholar, Windows Live Search Academic, and Serials Solutions' Central Search, relevant retrieval increases in direct relation to the complexity of the search interface. Central Search, as customized for Florida Gulf Coast University Library, permits far more complex searching than Google Scholar or Windows Academic and performs better than its simpler competitors. However, a close review
NASA Technical Reports Server (NTRS)
Reif, John H.
1987-01-01
A parallel compression algorithm for the 16,384 processor MPP machine was developed. The serial version of the algorithm can be viewed as a combination of on-line dynamic lossless test compression techniques (which employ simple learning strategies) and vector quantization. These concepts are described. How these concepts are combined to form a new strategy for performing dynamic on-line lossy compression is discussed. Finally, the implementation of this algorithm in a massively parallel fashion on the MPP is discussed.
Integrated Task And Data Parallel Programming: Language Design
NASA Technical Reports Server (NTRS)
Grimshaw, Andrew S.; West, Emily A.
1998-01-01
his research investigates the combination of task and data parallel language constructs within a single programming language. There are an number of applications that exhibit properties which would be well served by such an integrated language. Examples include global climate models, aircraft design problems, and multidisciplinary design optimization problems. Our approach incorporates data parallel language constructs into an existing, object oriented, task parallel language. The language will support creation and manipulation of parallel classes and objects of both types (task parallel and data parallel). Ultimately, the language will allow data parallel and task parallel classes to be used either as building blocks or managers of parallel objects of either type, thus allowing the development of single and multi-paradigm parallel applications. 1995 Research Accomplishments In February I presented a paper at Frontiers '95 describing the design of the data parallel language subset. During the spring I wrote and defended my dissertation proposal. Since that time I have developed a runtime model for the language subset. I have begun implementing the model and hand-coding simple examples which demonstrate the language subset. I have identified an astrophysical fluid flow application which will validate the data parallel language subset. 1996 Research Agenda Milestones for the coming year include implementing a significant portion of the data parallel language subset over the Legion system. Using simple hand-coded methods, I plan to demonstrate (1) concurrent task and data parallel objects and (2) task parallel objects managing both task and data parallel objects. My next steps will focus on constructing a compiler and implementing the fluid flow application with the language. Concurrently, I will conduct a search for a real-world application exhibiting both task and data parallelism within the same program m. Additional 1995 Activities During the fall I collaborated with Andrew Grimshaw and Adam Ferrari to write a book chapter which will be included in Parallel Processing in C++ edited by Gregory Wilson. I also finished two courses, Compilers and Advanced Compilers, in 1995. These courses complete my class requirements at the University of Virginia. I have only my dissertation research and defense to complete.
Parallel Composition Communication and Allow Hiding Parallel Processes
Mousavi, Mohammad
Parallel Composition Challenge (Dish1+Dish2) || Coke ? = (Dish1 || Coke)+(Dish2 || Coke) Mousavi: Parallel Composition Challenge (Dish1+Dish2) || Coke ? = (Dish1 || Coke)+(Dish2 || Coke) Faron Moller's Result Parallel Parallel Composition and |: Raisons d'^etre (Dish1 + Dish2) Coke (Dish1 Coke) + (Dish2 Coke) (Dish1 + Dish
King, Clarence; Bien, Julius, (lithographer)
1876-01-01
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'.
Some fast elliptic solvers on parallel architectures and their complexities
NASA Technical Reports Server (NTRS)
Gallopoulos, E.; Saad, Youcef
1989-01-01
The discretization of separable elliptic partial differential equations leads to linear systems with special block triangular matrices. Several methods are known to solve these systems, the most general of which is the Block Cyclic Reduction (BCR) algorithm which handles equations with nonconsistant coefficients. A method was recently proposed to parallelize and vectorize BCR. Here, the mapping of BCR on distributed memory architectures is discussed, and its complexity is compared with that of other approaches, including the Alternating-Direction method. A fast parallel solver is also described, based on an explicit formula for the solution, which has parallel computational complexity lower than that of parallel BCR.
Zhang, Xuetao; Huang, Jie; Yigit-Elliott, Serap; Rosenholtz, Ruth
2015-01-01
Observers can quickly search among shaded cubes for one lit from a unique direction. However, replace the cubes with similar 2-D patterns that do not appear to have a 3-D shape, and search difficulty increases. These results have challenged models of visual search and attention. We demonstrate that cube search displays differ from those with “equivalent” 2-D search items in terms of the informativeness of fairly low-level image statistics. This informativeness predicts peripheral discriminability of target-present from target-absent patches, which in turn predicts visual search performance, across a wide range of conditions. Comparing model performance on a number of classic search tasks, cube search does not appear unexpectedly easy. Easy cube search, per se, does not provide evidence for preattentive computation of 3-D scene properties. However, search asymmetries derived from rotating and/or flipping the cube search displays cannot be explained by the information in our current set of image statistics. This may merely suggest a need to modify the model's set of 2-D image statistics. Alternatively, it may be difficult cube search that provides evidence for preattentive computation of 3-D scene properties. By attributing 2-D luminance variations to a shaded 3-D shape, 3-D scene understanding may slow search for 2-D features of the target. PMID:25780063
Optimized data communications in a parallel computer
Faraj, Daniel A
2014-10-21
A parallel computer includes nodes that include a network adapter that couples the node in a point-to-point network and supports communications in opposite directions of each dimension. Optimized communications include: receiving, by a network adapter of a receiving compute node, a packet--from a source direction--that specifies a destination node and deposit hints. Each hint is associated with a direction within which the packet is to be deposited. If a hint indicates the packet to be deposited in the opposite direction: the adapter delivers the packet to an application on the receiving node; forwards the packet to a next node in the opposite direction if the receiving node is not the destination; and forwards the packet to a node in a direction of a subsequent dimension if the hints indicate that the packet is to be deposited in the direction of the subsequent dimension.
Optimized data communications in a parallel computer
Faraj, Daniel A.
2014-08-19
A parallel computer includes nodes that include a network adapter that couples the node in a point-to-point network and supports communications in opposite directions of each dimension. Optimized communications include: receiving, by a network adapter of a receiving compute node, a packet--from a source direction--that specifies a destination node and deposit hints. Each hint is associated with a direction within which the packet is to be deposited. If a hint indicates the packet to be deposited in the opposite direction: the adapter delivers the packet to an application on the receiving node; forwards the packet to a next node in the opposite direction if the receiving node is not the destination; and forwards the packet to a node in a direction of a subsequent dimension if the hints indicate that the packet is to be deposited in the direction of the subsequent dimension.
Dynamic graphics using quasi parallelism
Kenneth M. Kahn; Carl Hewitt
1978-01-01
Dynamic computer graphics is best represented as several processes operating in parallel. Full parallel processing, however, entails much complex mechanism making it difficult to write simple, intuitive programs for generating computer animation. What is presented in this paper is a simple means of attaining the appearance of parallelism and the ability to program the graphics in a conceptually parallel fashion
Parallel Processing in Amplitude Analysis
Evans, Hal
Parallel Processing in Amplitude Analysis Lecture 2 of 2 on Parallel Processing Physics 411/610 March 31, 2011 Matt Shepherd #12;M. R. Shepherd Parallel Processing Lecture 2 March 31, 2011 Outline · Theoretical Background · Experimental Technique · Application of Parallel Computing · Method of Maximum
Sublattice parallel replica dynamics.
Martínez, Enrique; Uberuaga, Blas P; Voter, Arthur F
2014-06-01
Exascale computing presents a challenge for the scientific community as new algorithms must be developed to take full advantage of the new computing paradigm. Atomistic simulation methods that offer full fidelity to the underlying potential, i.e., molecular dynamics (MD) and parallel replica dynamics, fail to use the whole machine speedup, leaving a region in time and sample size space that is unattainable with current algorithms. In this paper, we present an extension of the parallel replica dynamics algorithm [A. F. Voter, Phys. Rev. B 57, R13985 (1998)] by combining it with the synchronous sublattice approach of Shim and Amar [ and , Phys. Rev. B 71, 125432 (2005)], thereby exploiting event locality to improve the algorithm scalability. This algorithm is based on a domain decomposition in which events happen independently in different regions in the sample. We develop an analytical expression for the speedup given by this sublattice parallel replica dynamics algorithm and compare it with parallel MD and traditional parallel replica dynamics. We demonstrate how this algorithm, which introduces a slight additional approximation of event locality, enables the study of physical systems unreachable with traditional methodologies and promises to better utilize the resources of current high performance and future exascale computers. PMID:25019913
Sublattice parallel replica dynamics
NASA Astrophysics Data System (ADS)
Martínez, Enrique; Uberuaga, Blas P.; Voter, Arthur F.
2014-06-01
Exascale computing presents a challenge for the scientific community as new algorithms must be developed to take full advantage of the new computing paradigm. Atomistic simulation methods that offer full fidelity to the underlying potential, i.e., molecular dynamics (MD) and parallel replica dynamics, fail to use the whole machine speedup, leaving a region in time and sample size space that is unattainable with current algorithms. In this paper, we present an extension of the parallel replica dynamics algorithm [A. F. Voter, Phys. Rev. B 57, R13985 (1998), 10.1103/PhysRevB.57.R13985] by combining it with the synchronous sublattice approach of Shim and Amar [Y. Shim and J. G. Amar, Phys. Rev. B 71, 125432 (2005), 10.1103/PhysRevB.71.125432], thereby exploiting event locality to improve the algorithm scalability. This algorithm is based on a domain decomposition in which events happen independently in different regions in the sample. We develop an analytical expression for the speedup given by this sublattice parallel replica dynamics algorithm and compare it with parallel MD and traditional parallel replica dynamics. We demonstrate how this algorithm, which introduces a slight additional approximation of event locality, enables the study of physical systems unreachable with traditional methodologies and promises to better utilize the resources of current high performance and future exascale computers.
Variations on Multi-Core Nested Depth-First Search
Alfons Laarman; Jaco van de Pol; J. Barnat; K. Heljanko
2011-01-01
Recently, two new parallel algorithms for on-the-fly model checking of LTL properties were presented at the same conference: Automated Technology for Verification and Analysis, 2011. Both approaches extend Swarmed NDFS, which runs several sequential NDFS instances in parallel. While parallel random search already speeds up detection of bugs, the workers must share some global information in order to speed up
NASA Astrophysics Data System (ADS)
Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Balek, P.; Balestri, T.; Balli, F.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, K.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Beringer, J.; Bernard, C.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertsche, C.; Bertsche, D.; Besana, M. I.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blanco, J. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boddy, C. R.; Boehler, M.; Bogaerts, J. A.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutouil, S.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozic, I.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, J.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Bruschi, M.; Bryngemark, L.; Buanes, T.; Buat, Q.; Bucci, F.; Buchholz, P.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Buehrer, F.; Bugge, L.
2015-05-01
A search is presented for the direct pair production of a chargino and a neutralino , where the chargino decays to the lightest neutralino and the boson, , while the neutralino decays to the lightest neutralino and the 125 GeV Higgs boson, . The final states considered for the search have large missing transverse momentum, an isolated electron or muon, and one of the following: either two jets identified as originating from bottom quarks, or two photons, or a second electron or muon with the same electric charge. The analysis is based on 20.3 of proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with the Standard Model expectations, and limits are set in the context of a simplified supersymmetric model.
Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdel Khalek, Samah; Abdelalim, Ahmed Ali; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alam, Mohammad; Alam, Muhammad Aftab; Albert, Justin; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Allbrooke, Benedict; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alonso, Francisco; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amelung, Christoph; Ammosov, Vladimir; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amram, Nir; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Andrieux, Marie-Laure; Anduaga, Xabier; Angelidakis, Stylianos; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Ask, Stefan; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Atkinson, Markus; Aubert, Bernard; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Backus Mayes, John; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Balek, Petr; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Basye, Austin; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beale, Steven; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Begel, Michael; Behar Harpaz, Silvia; Behera, Prafulla; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertolucci, Federico; Besana, Maria Ilaria; Besjes, Geert-Jan; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare
2013-01-01
A search for direct chargino production in anomaly-mediated supersymmetry breaking scenarios is performed in pp collisions at $\\sqrt{s}$ = 7 TeV 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.
Parallelizing the spectral transform method, part 2
NASA Astrophysics Data System (ADS)
Walker, D. W.; Worley, P. H.; Drake, J. B.
1991-07-01
This paper describes the parallelization and performance of the spectral method for solving the shallow water equations on the surface of a sphere using a 128-node Intel iPSC/860 hypercube. The shallow water equations form a computational kernel of more complex climate models. This work is part of a research program to develop climate models that are capable of much longer simulations at a significantly finer resolution than current models. Such models are important in understanding the effects of the increasing atmospheric concentrations of greenhouse gases, and the computational requirements are so large that massively parallel multiprocessors will be necessary to run climate models simulations in a reasonable amount of time. The spectral method involves the transformation of data between the physical, Fourier, and spectral domains. Each of these domains is two-dimensional. The spectral method performs Fourier transforms in the longitude direction followed by summation in the latitude direction to evaluate the discrete spectral transform. A simple way of parallelizing the spectral code is to decompose the physical problem domain in just the latitude direction. This allows an optimized sequential FFT algorithm to be used in the longitude direction. However, this approach limits the number of processors that can be brought to bear on the problem. Decomposing the problem over both directions allows the parallelism inherent in the problem to be exploited more effectively - the grain size is reduced and more processors can be used. Results are presented that show that decomposing over both directions does result in a more rapid solution of the problem. The importance of minimizing communication latency and overlapping communication with calculation is stressed. General methods for doing this, that may be applied to many other problems, are discussed.
Parallel channel flow excursions
Johnston, B.S.
1990-01-01
Among the many known types of vapor-liquid flow instability is the excursion which may occur in heated parallel channels. Under certain conditions, the pressure drop requirement in a heated channel may increase with decreases in flow rate. This leads to an excursive reduction in flow. For channels heated by electricity or nuclear fission, this can result in overheating and damage to the channel. In the design of any parallel channel device, flow excursion limits should be established. After a review of parallel channel behavior and analysis, a conservative criterion will be proposed for avoiding excursions. In support of this criterion, recent experimental work on boiling in downward flow will be described. 5 figs.
Parallelizing Quantum Circuits
Anne Broadbent; Elham Kashefi
2007-04-13
We present a novel automated technique for parallelizing quantum circuits via forward and backward translation to measurement-based quantum computing patterns and analyze the trade off in terms of depth and space complexity. As a result we distinguish a class of polynomial depth circuits that can be parallelized to logarithmic depth while adding only polynomial many auxiliary qubits. In particular, we provide for the first time a full characterization of patterns with flow of arbitrary depth, based on the notion of influencing paths and a simple rewriting system on the angles of the measurement. Our method leads to insightful knowledge for constructing parallel circuits and as applications, we demonstrate several constant and logarithmic depth circuits. Furthermore, we prove a logarithmic separation in terms of quantum depth between the quantum circuit model and the measurement-based model.
Ramachandran, Vijaya
in this file.) Parallel Open Ear Decomposition with Applications to Graph Biconnectivity and Triconnectivity describe this method for searching undirected graphs, called ``open ear decomposition'', and we relate and we relate it to a sequential algorithm based on depthfirst search. We then apply open ear
Ramachandran, Vijaya
in this file.) Parallel Open Ear Decomposition with Applications to Graph Biconnectivity and Triconnectivity this method for searching undirected graphs, called open ear decomposition", and we relate this decomposition relate it to a sequential algorithm based on depth- rst search. We then apply open ear decomposition
Semantic knowledge representation and its parallel reasoning applications
Brown, S.N.
1989-01-01
This dissertation presents a new way of thinking about machine reasoning as applied to the domain of knowledge as it appears in nature, along with its taxonomy. The new way of thinking involves a new approach for the representation of this natural knowledge taxonomy: the Semantic Overlapped Tree (S.O.Tree). This structure differs from previous semantic structures in that order is provided in the form of an overlapped tree while maintaining its semantic integrity. To facilitate machine reasoning, algorithms are presented for efficient operation on the S.O.Tree, including sequential search, insert, and delete, and parallel search, insert and delete. The speedup performance of the parallel algorithms is provided as a function of the number of processors, as well as processor efficiency. The speedup asymptote for the parallel algorithms for search, insert and delete is 20.21, 13.93 and 11.80, respectively. Also presented is a hybrid memory architecture which permits the hardware to map to the topology of the problem domain. The hybrid nature of this memory configuration consists of a combination of globally shared memory and local/private memory. This new method for knowledge representation, the machine's capacity to carry out parallel reasoning, and the hybrid memory architecture combine to form a parallel-reasoning system which well exemplifies the domain-driven concept.
Parallel computation of a maximum-likelihood estimator of a physical map.
Bhandarkar, S M; Machaka, S A; Shete, S S; Kota, R N
2001-01-01
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. PMID:11238392
Numerical wind tunnel and parallel FORTRAN
NASA Astrophysics Data System (ADS)
Nakamura, Takashi; Yoshida, Masahiro; Fukuda, Masahiro; Takamura, Moriyuki; Okada, Shin
1992-12-01
Computational Fluid Dynamics (CFD) requires computers 100 times faster than the Fujitsu VP400 in effective speed. Such a processor can be suitably called the 'Numerical Wind Tunnel'. Numerical Wind Tunnel (NWT) is a parallel computer system of a distributed memory architecture composed of vector processors connected through cross-bar network. In this report, the system configuration, processing element, and interconnection network and communication mechanism of the NWT are shown. Fundamental functions global data, parallel execution of DO-loop, and data decomposition and allocation, which the language-processor system has to provide in order to realize parallel execution on the NWT are also shown. FORTRAN 77 is chosen as a basic programming language for NWT and some compiler directives are added to make effective use of the NWT.
Line-drawing algorithms for parallel machines
NASA Technical Reports Server (NTRS)
Pang, Alex T.
1990-01-01
The fact that conventional line-drawing algorithms, when applied directly on parallel machines, can lead to very inefficient codes is addressed. It is suggested that instead of modifying an existing algorithm for a parallel machine, a more efficient implementation can be produced by going back to the invariants in the definition. Popular line-drawing algorithms are compared with two alternatives; distance to a line (a point is on the line if sufficiently close to it) and intersection with a line (a point on the line if an intersection point). For massively parallel single-instruction-multiple-data (SIMD) machines (with thousands of processors and up), the alternatives provide viable line-drawing algorithms. Because of the pixel-per-processor mapping, their performance is independent of the line length and orientation.
Reed, Nancy E.
. remove Help window CÂx 1 scroll Help window ESC CÂv apropos: show commands matching a string CÂh a show garbaged screen CÂl Incremental Search search forward CÂs search backward CÂr regular expression search CÂMÂs reverse regular expression search CÂMÂr select previous search string MÂp select next later search string
John Dubinski
1996-03-18
We describe a new implementation of a parallel N-body tree code. The code is load-balanced using the method of orthogonal recursive bisection to subdivide the N-body system into independent rectangular volumes each of which is mapped to a processor on a parallel computer. On the Cray T3D, the load balance in the range of 70-90\\% depending on the problem size and number of processors. The code can handle simulations with $>$ 10 million particles roughly a factor of 10 greater than allowed in vectorized tree codes.
NASA Astrophysics Data System (ADS)
McWhirter, John G.
1989-12-01
The potential application of parallel computing techniques to digital signal processing for radar is discussed and two types of regular array processor are discussed. The first type of processor is the systolic or wavefront processor. The application of this type of processor to adaptive beamforming is discussed and the joint STL-RSRE adaptive antenna processor test-bed is reviewed. The second type of regular array processor is the SIMD parallel computer. One such processor, the Mil-DAP, is described, and its application to a varied range of radar signal processing tasks is discussed.
Speeding up parallel processing
NASA Technical Reports Server (NTRS)
Denning, Peter J.
1988-01-01
In 1967 Amdahl expressed doubts about the ultimate utility of multiprocessors. The formulation, now called Amdahl's law, became part of the computing folklore and has inspired much skepticism about the ability of the current generation of massively parallel processors to efficiently deliver all their computing power to programs. The widely publicized recent results of a group at Sandia National Laboratory, which showed speedup on a 1024 node hypercube of over 500 for three fixed size problems and over 1000 for three scalable problems, have convincingly challenged this bit of folklore and have given new impetus to parallel scientific computing.
Adaptive parallel logic networks
NASA Technical Reports Server (NTRS)
Martinez, Tony R.; Vidal, Jacques J.
1988-01-01
Adaptive, self-organizing concurrent systems (ASOCS) that combine self-organization with massive parallelism for such applications as adaptive logic devices, robotics, process control, and system malfunction management, are presently discussed. In ASOCS, an adaptive network composed of many simple computing elements operating in combinational and asynchronous fashion is used and problems are specified by presenting if-then rules to the system in the form of Boolean conjunctions. During data processing, which is a different operational phase from adaptation, the network acts as a parallel hardware circuit.
Parallelization of Thermochemical Nanolithography
NASA Astrophysics Data System (ADS)
Curtis, Jennifer E.; Carroll, Keith; Lu, Xi; Kim, Suenne; Gao, Yang; Kim, Hoe-Joon; Somnath, Suhas; Polloni, Laura; Sordan, Roman; King, William; Riedo, Elisa
2014-03-01
One of the most pressing technological challenges in the development of next generation nanoscale devices is the rapid, parallel, precise and robust fabrication of nanostructures. We demonstrate the possibility to parallelize thermochemical nanolithography (TCNL) by employing five nano-tips for the fabrication of luminescent polymer nanostructures and graphene-based nanoribbons. This work has been supported by the National Science Foundation PHYS 0848797 (J.E.C.), CMMI 1100290 (E.R., W.P.K), MRSEC program DMR 0820382 (E.R., J.E.C.), and the Office of Basic Energy Sciences DOE DE-FG02-06ER46293 (E.R.).
Architecture studies and system demonstrations for optical parallel processor for AI and NI
NASA Astrophysics Data System (ADS)
Lee, Sing H.
1988-03-01
In solving deterministic AI problems the data search for matching the arguments of a PROLOG expression causes serious bottleneck when implemented sequentially by electronic systems. To overcome this bottleneck we have developed the concepts for an optical expert system based on matrix-algebraic formulation, which will be suitable for parallel optical implementation. The optical AI system based on matrix-algebraic formation will offer distinct advantages for parallel search, adult learning, etc.
Exploiting data parallelism in the Image Content Engine
NASA Astrophysics Data System (ADS)
Miller, W. Marcus; Garlick, Jim E.; Weinert, George F.; Abdulla, Ghaleb M.
2006-05-01
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.
From Distributed Memory Cycle Detection to Parallel LTL Model Checking
Jiri Barnat; Lubos Brim; Jakub Chaloupka
2005-01-01
In (2) we proposed a parallel graph algorithm for detecting cycles in very large di- rected graphs distributed over a network of workstations. The algorithm employs back-level edges as computed by the breadth first search. In this paper we describe how to turn the algorithm into an explicit state distributed memory LTL model checker by extending it with detection of
Exploiting Data Parallelism in the Image Content Engine
Miller, W M; Garlick, J E; Weinert, G F; Abdulla, G M
2006-03-09
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.
Parallel computers and parallel algorithms for CFD: An introduction
NASA Astrophysics Data System (ADS)
Roose, Dirk; Vandriessche, Rafael
1995-10-01
This text presents a tutorial on those aspects of parallel computing that are important for the development of efficient parallel algorithms and software for computational fluid dynamics. We first review the main architectural features of parallel computers and we briefly describe some parallel systems on the market today. We introduce some important concepts concerning the development and the performance evaluation of parallel algorithms. We discuss how work load imbalance and communication costs on distributed memory parallel computers can be minimized. We present performance results for some CFD test cases. We focus on applications using structured and block structured grids, but the concepts and techniques are also valid for unstructured grids.
SMMH--A Parallel Heuristic for Combinatorial Optimization Problems
Domingues, Guilherme; Morie, Yoshiyuki [Institute of Systems and Information Technologies, Fukuoka (Japan); Research Institute for Information Technology, Kyushu University (Japan); Gu, Feng Long; Nanri, Takeshi [Research Institute for Information Technology, Kyushu University (Japan); Murakami, Kazuaki [Research Institute for Information Technology, Kyushu University (Japan); Department of Informatics, Kyushu University (Japan)
2007-12-26
The process of finding one or more optimal solutions for answering combinatorial optimization problems bases itself on the use of algorithms instances. Those instances usually have to explore a very large search spaces. Heuristics search focusing on the use of High-Order Hopfield neural networks is a largely deployed technique for very large search space. It can be established a very powerful analogy towards the dynamics evolution of a physics spin-glass system while minimizing its own energy and the energy function of the network. This paper presents a new approach for solving combinatorial optimization problems through parallel simulations, based on a High-Order Hopfield neural network using MPI specification.
SMMH - A Parallel Heuristic for Combinatorial Optimization Problems
Domingues, Guilherme; Morie, Yoshiyuki [Institute of Systems and Information Technologies, Fukuoka (Japan); Research Institute for Information Technology, Kyushu University (Japan); Gu, Feng Long; Nanri, Takeshi [Research Institute for Information Technology, Kyushu University (Japan); Murakami, Kazuaki [Research Institute for Information Technology, Kyushu University (Japan); Department of Informatics, Kyushu University (Japan)
2007-12-26
The process of finding one or more optimal solutions for answering combinatorial optimization problems bases itself on the use of algorithms instances. Those instances usually have to explore a very large search spaces. Heuristics search focusing on the use of High-Order Hopfield neural networks is a largely deployed technique for very large search space. It can be established a very powerful analogy towards the dynamics evolution of a physics spin-glass system while minimizing its own energy and the energy function of the network. This paper presents a new approach for solving combinatorial optimization problems through parallel simulations, based on a High-Order Hopfield neural network using MPI specification.
NSDL National Science Digital Library
In 1996 Yahoo added this enhancement to its popular Internet directory service. It's People Search allows you to find telephone numbers and email addresses by entering a search form. The telephone directory is supplied by Database America (the provider of the Switchboard.com database), and the email interface directly queries Four11.com.
MPI-based Parallelization for ILP-based Multi-relational Concept Discovery
Alev Mutlu; Pinar Senkul; Yusuf Kavurucu
2011-01-01
Multi-relational concept discovery is a predictive learning task that aims to discover descriptions of a target concept in the light of past experiences. Parallelization has emerged as a solution to deal with efficiency and scalability issues relating to large search spaces in concept discovery systems. In this work, we describe a parallelization method for the ILP-based concept discovery system called
Zhe Wang; Zhixing Wang; Wentao Liu; Yucheng Lei
2001-01-01
We present an algorithm, called the boundary search method, to determine the workspace of a parallel machine tool, and taking the parallel machine tool BJ-30 developed by the Harbin Institute of Technology as an example, its workspace based on the cutter point is calculated. We also analyze the boundary workspace in order to expand its operating scope. Due to the
Uwe Gropengiesser
1995-01-01
Using a simple master-slave parallelization scheme given by A. Berengoltz and J. Adler, we observe superlinear speedups during the search algorithm for the ground state energy of the ±J spin glass via biologically motivated methods. With this parallel implementation we are able to improve earlier sequentially-calculated estimates for the infinite lattice ground state energy of the square and simple cubic
Fast and processor-efficient parallel algorithms for reducible-flow graphs. Technical report
Ramachandran
1988-01-01
This document presents parallel NC algorithms for recognizing reducible flow graphs (rfg's), and for finding dominators, minimum feedback vertex sets, and a depth first-search numbering in an rfg. All of these algorithms run in polylog parallel time using M (n) processors, where M (n) is the number of processors needed to multiply two nxn matrices in polylog time; this is