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Faculty Publications

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Articles 6541 - 6570 of 9020

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Upper Limit Map Of A Background Of Gravitational Waves, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, G. Billingsley, R. Biswas Oct 2007

Upper Limit Map Of A Background Of Gravitational Waves, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, G. Billingsley, R. Biswas

Faculty Publications

We searched for an anisotropic background of gravitational waves using data from the LIGO S4 science run and a method that is optimized for point sources. This is appropriate if, for example, the gravitational wave background is dominated by a small number of distinct astrophysical sources. No signal was seen. Upper limit maps were produced assuming two different power laws for the source strain power spectrum. For an f-3 power law and using the 50 Hz to 1.8 kHz band the upper limits on the source strain power spectrum vary between 1.2×10-48Hz-1 (100Hz/f)3 and 1.2×10-47Hz-1 (100Hz/f)3, depending on the position …

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Excision Without Excision, David Brown, Olivier Sarbach, Erik Schnetter, Manuel Tiglio, Peter Diener, Ian Hawke, Denis Pollney Oct 2007

Excision Without Excision, David Brown, Olivier Sarbach, Erik Schnetter, Manuel Tiglio, Peter Diener, Ian Hawke, Denis Pollney

Faculty Publications

to turducken (turduckens, turduckening, turduckened, turduckened) [math.]: To stuff a black hole. We analyze and apply an alternative to black hole excision based on smoothing the interior of black holes with arbitrary initial data, and solving the vacuum Einstein evolution equations everywhere. By deriving the constraint propagation system for our hyperbolic formulation of the BSSN evolution system we rigorously prove that the constraints propagate causally and so any constraint violations introduced inside the black holes cannot affect the exterior spacetime. We present evolutions of Cook-Pfeiffer binary black hole initial configurations showing that these techniques appear to work robustly for generic …

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Upper Limit Map Of A Background Of Gravitational Waves, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales Oct 2007

Upper Limit Map Of A Background Of Gravitational Waves, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales

Faculty Publications

We searched for an anisotropic background of gravitational waves using data from the LIGO S4 science run and a method that is optimized for point sources. This is appropriate if, for example, the gravitational wave background is dominated by a small number of distinct astrophysical sources. No signal was seen. Upper limit maps were produced assuming two different power laws for the source strain power spectrum. For an f-3 power law and using the 50 Hz to 1.8 kHz band the upper limits on the source strain power spectrum vary between 1.2×10-48Hz-1 (100Hz/f)3 and 1.2×10-47Hz-1 (100Hz/f)3, depending on the position …

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High-Et Dijet Photoproduction At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi Oct 2007

High-Et Dijet Photoproduction At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

The cross section for high-ET dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8pb-1. The events were required to have a virtuality of the incoming photon, Q2, of less than 1GeV2 and a photon-proton center-of-mass energy in the range 14215GeV and pseudorapidity (with respect to the proton beam direction) requirements of -1<ηjet1,2

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Searches For Periodic Gravitational Waves From Unknown Isolated Sources And Scorpius X-1: Results From The Second Ligo Science Run, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, S. J. Berukoff, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, Tiffany Z. Summerscales Oct 2007

Searches For Periodic Gravitational Waves From Unknown Isolated Sources And Scorpius X-1: Results From The Second Ligo Science Run, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, S. J. Berukoff, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, Tiffany Z. Summerscales

Faculty Publications

We carry out two searches for periodic gravitational waves using the most sensitive few hours of data from the second LIGO science run. Both searches exploit fully coherent matched filtering and cover wide areas of parameter space, an innovation over previous analyses which requires considerable algorithm development and computational power. The first search is targeted at isolated, previously unknown neutron stars, covers the entire sky in the frequency band 160-728.8 Hz, and assumes a frequency derivative of less than 4×10-10Hz/s. The second search targets the accreting neutron star in the low-mass x-ray binary Scorpius X-1 and covers the frequency bands …

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Poly[(Nitrato-KO)Tris((Μ3-1h-1,2,4-Triazolato)Dizinc(Ii)]: A Three-Dimensional Coordination Polymer, Josephy M. Ellsworth, Mark D. Smith, Hans-Conrad Zur Loye Oct 2007

Poly[(Nitrato-KO)Tris((Μ3-1h-1,2,4-Triazolato)Dizinc(Ii)]: A Three-Dimensional Coordination Polymer, Josephy M. Ellsworth, Mark D. Smith, Hans-Conrad Zur Loye

Faculty Publications

In the title compound, [Zn2(C2H2N3)3(NO3)], there are two unique Zn atoms, both with site symmetry m. One forms a ZnN3O tetrahedron and the other a ZnN6 octahedron. One and a half 1H-1,2,4-triazolate ligands, with the half-ligand located on a mirror plane, and a disordered nitrate anion complete the asymmetric unit of the structure. The polymeric connectivity is three-dimensional.

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Structural Characterization Using The Multiple Scattering Effects In Grazing-Incidence Small-Angle X-Ray Scattering, Byeongdu Lee, Chieh-Tsung Lo, P. Thiyagarajan, Dong R. Lee, Zhongwei Niu, Qian Wang Oct 2007

Structural Characterization Using The Multiple Scattering Effects In Grazing-Incidence Small-Angle X-Ray Scattering, Byeongdu Lee, Chieh-Tsung Lo, P. Thiyagarajan, Dong R. Lee, Zhongwei Niu, Qian Wang

Faculty Publications

The multiple scattering effects present in grazing-incidence small-angle X-ray scattering (GISAXS) data and interference between them are addressed theoretically as well as experimentally with measurement of a series of patterns at different incident angles, referred to as `incident-angle-resolved GISAXS' (IAR-GISAXS). X-ray reflectivity (XR), GISAXS and IAR-GISAXS of virus particles on Si-substrate supported-polystyrene films have been measured and all the data have been analyzed with appropriate formalisms. It was found that under certain conditions it is possible to extract the correct structural features of the materials from the GISAXS/IAR-GISAXS data using the kinematic SAXS formalisms, without the need to use the …

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Nanoindentation Of The A And C Domains In A Tetragonal Batio3 Single Crystal, Young-Bae Park, Matthew J. Dicken, Zhi-Hui Xu, Xiaodong Li Oct 2007

Nanoindentation Of The A And C Domains In A Tetragonal Batio3 Single Crystal, Young-Bae Park, Matthew J. Dicken, Zhi-Hui Xu, Xiaodong Li

Faculty Publications

Nanoindentation in conjunction with piezoresponse force microscopy was used to study domain switching and to measure the mechanical properties of individual ferroelectric domains in a tetragonal BaTiO3 single crystal. It was found that nanoindentation has induced local domain switching; the a and c domains of BaTiO3 have different elastic moduli but similar hardness.Nanoindentationmodulus mapping on the a and c domains further confirmed such difference in elasticity. Finite element modeling was used to simulate the von Mises stress and plastic strain profiles of the indentations on both a and c domains, which introduces a much higher stress level than …

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Spilling: Expanding Hand Held Interaction To Touch Table Displays, Jeffrey Clement, Dan R. Olsen Jr., Aaron Pace Oct 2007

Spilling: Expanding Hand Held Interaction To Touch Table Displays, Jeffrey Clement, Dan R. Olsen Jr., Aaron Pace

Faculty Publications

We envision a nomadic model of interaction where the personal computer fits in your pocket. Such a computer is extremely limited in screen space. A technique is described for “spilling” the display of a hand held computer onto a much larger table top display surface. Because our model of nomadic computing frequently involves the use of untrusted display services we restrict interactive input to the hand held. Navigation techniques such as scrolling or turning the display can be expressed through the table top. The orientation and position of the hand held on the table top is detected using three conductive …

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Robust Multi-Modal Biometric Fusion Via Multiple Svms, Jonathan Dinerstein, Sabra Dinerstein, Dan A. Ventura Oct 2007

Robust Multi-Modal Biometric Fusion Via Multiple Svms, Jonathan Dinerstein, Sabra Dinerstein, Dan A. Ventura

Faculty Publications

Existing learning-based multi-modal biometric fusion techniques typically employ a single static Support Vector Machine (SVM). This type of fusion improves the accuracy of biometric classification, but it also has serious limitations because it is based on the assumptions that the set of biometric classifiers to be fused is local, static, and complete. We present a novel multi-SVM approach to multi-modal biometric fusion that addresses the limitations of existing fusion techniques and show empirically that our approach retains good classification accuracy even when some of the biometric modalities are unavailable.

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A Phenomenological Template Family For Black-Hole Coalescence Waveforms, P. Ajith, S. Babak, Y. Chen, M. Hewitson, B. Krishnan, J. T. Whelan, B. Brügmann, P. Diener, J. Gonzalez, M. Hannam, S. Husa, M. Koppitz, D. Pollney, L. Rezzolla, L. Santamaría, A. M. Sintes, U. Sperhake, J. Thornburg Oct 2007

A Phenomenological Template Family For Black-Hole Coalescence Waveforms, P. Ajith, S. Babak, Y. Chen, M. Hewitson, B. Krishnan, J. T. Whelan, B. Brügmann, P. Diener, J. Gonzalez, M. Hannam, S. Husa, M. Koppitz, D. Pollney, L. Rezzolla, L. Santamaría, A. M. Sintes, U. Sperhake, J. Thornburg

Faculty Publications

Recent progress in numerical relativity has enabled us to model the non-perturbative merger phase of the binary black-hole coalescence problem. Based on these results, we propose a phenomenological family of waveforms which can model the inspiral, merger and ring-down stages of black-hole coalescence. We also construct a template bank using this family of waveforms and discuss its implementation in the search for signatures of gravitational waves produced by black-hole coalescences in the data of ground-based interferometers. This template bank might enable us to extend the present inspiral searches to higher-mass binary black-hole systems, i.e., systems with total mass greater than …

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An Experimental Technique For The Evaluation Of Strain Dependent Material Properties Of Hard Coatings, Shad A. Reed, Anthony N. Palazotto, William P. Baker Oct 2007

An Experimental Technique For The Evaluation Of Strain Dependent Material Properties Of Hard Coatings, Shad A. Reed, Anthony N. Palazotto, William P. Baker

Faculty Publications

A novel vibration experiment consisting of a free-free boundary condition, an electromagnetic excitation source, a vacuum chamber, and a laser vibrometer based surface measurement system has been developed that permits high levels of excitation on highly damped specimens with a minimal amount of unwanted systematic error. While some of the aspects of this experiment are not unique, when combined with a processing technique that accounts for the nonlinearities present in the system, this experiment permits, accurate measurement of strain dependent stiffness and damping properties of hard coatings at high strain levels. This procedure has been demonstrated using a titanium beam …

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A Data-Dependent Distance Measure For Transductive Instance-Based Learning, Jared Lundell, Dan A. Ventura Oct 2007

A Data-Dependent Distance Measure For Transductive Instance-Based Learning, Jared Lundell, Dan A. Ventura

Faculty Publications

We consider learning in a transductive setting using instance-based learning (k-NN) and present a method for constructing a data-dependent distance “metric” using both labeled training data as well as available unlabeled data (that is to be classified by the model). This new data-driven measure of distance is empirically studied in the context of various instance-based models and is shown to reduce error (compared to traditional models) under certain learning conditions. Generalizations and improvements are suggested.

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Adtrees For Sequential Data And N-Gram Counting, Robert Van Dam, Dan A. Ventura Oct 2007

Adtrees For Sequential Data And N-Gram Counting, Robert Van Dam, Dan A. Ventura

Faculty Publications

We consider the problem of efficiently storing n-gram counts for large n over very large corpora. In such cases, the efficient storage of sufficient statistics can have a dramatic impact on system performance. One popular model for storing such data derived from tabular data sets with many attributes is the ADtree. Here, we adapt the ADtree to benefit from the sequential structure of corpora-type data. We demonstrate the usefulness of our approach on a portion of the well-known Wall Street Journal corpus from the Penn Treebank and show that our approach is exponentially more efficient than the naïve approach to …

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Changing Course: Navigating Life After Fifty, E Michael Brady Phd Oct 2007

Changing Course: Navigating Life After Fifty, E Michael Brady Phd

Faculty Publications

The article reviews the book Changing Course: Navigating Life After Fifty, by William A. Sadler and James H. Kreft.

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Hypoxia In The Northern Gulf Of Mexico: Does The Science Support The Plan To Reduce, Mitigate, And Control Hypoxia?, Nancy N. Rabalais, R. Eugene Turner, B.K. Sen Gupta, D. F. Boesch, P. Chapman, M. C. Murrell Oct 2007

Hypoxia In The Northern Gulf Of Mexico: Does The Science Support The Plan To Reduce, Mitigate, And Control Hypoxia?, Nancy N. Rabalais, R. Eugene Turner, B.K. Sen Gupta, D. F. Boesch, P. Chapman, M. C. Murrell

Faculty Publications

We update and reevaluate the scientific information on the distribution, history, and causes of continental shelf hypoxia that supports the 2001 Action Plan for Reducing, Mitigating, and Controlling Hypoxia in the Northern Gulf of Mexico (Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2001), incorporating data, publications, and research results produced since the 1999 integrated assessment. The metric of mid-summer hypoxic area on the Louisiana-Texas shelf is an adequate and suitable measure for continued efforts to reduce nutrients loads from the Mississippi River and hypoxia in the northern Gulf of Mexico as outlined in the Action Plan. More frequent measurements …

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The Asymptotic Density Of Finite-Order Elements In Virtually Nilpotent Groups, Pallavi Dani Oct 2007

The Asymptotic Density Of Finite-Order Elements In Virtually Nilpotent Groups, Pallavi Dani

Faculty Publications

Let Γ be a finitely generated group with a given word metric. The asymptotic density of elements in Γ that have a particular property P is the limit, as r → ∞, of the proportion of elements in the ball of radius r which have the property P. We obtain a formula to compute the asymptotic density of finite-order elements in any virtually nilpotent group. Further, we show that the spectrum of numbers that occur as such asymptotic densities consists of exactly the rational numbers in [0, 1). © 2007 Elsevier Inc. All rights reserved.

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Instrumentation And Metrology For Single Rna Counting In Biological Complexes Or Nanoparticles By A Single-Molecule Dual-View System, Hui Zhang, Dan Shu, Faqing Huang, Peixuan Guo Oct 2007

Instrumentation And Metrology For Single Rna Counting In Biological Complexes Or Nanoparticles By A Single-Molecule Dual-View System, Hui Zhang, Dan Shu, Faqing Huang, Peixuan Guo

Faculty Publications

Limited by the spatial resolution of optical microscopy, direct detection or counting of single components in biological complexes or nanoparticles is challenging, especially for RNA, which is conformationally versatile and structurally flexible. We report here the assembly of a customized single-molecule dual-viewing total internal reflection fluorescence imaging system for direct counting of RNA building blocks. The RNA molecules were labeled with a single fluorophore by in vitro transcription in the presence of a fluorescent AMP. Precise calculation of identical or mixed pRNA building blocks of one, two, three, or six copies within the bacteriophage phi29 DNA packaging motor or other …

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Ecological Interfaces For Improving Mobile Robot Teleoperation, Michael A. Goodrich, Curtis W. Nielsen, Robert W. Ricks Oct 2007

Ecological Interfaces For Improving Mobile Robot Teleoperation, Michael A. Goodrich, Curtis W. Nielsen, Robert W. Ricks

Faculty Publications

Navigation is an essential element of many remote robot operations including search and rescue, reconnaissance, and space exploration. Previous reports on using remote mobile robots suggest that navigation is difficult due to poor situation awareness. It has been recommended by experts in human–robot interaction that interfaces between humans and robots provide more spatial information and better situational context in order to improve an operator’s situation awareness. This paper presents an ecological interface paradigm that combines video, map, and robotpose information into a 3-D mixed-reality display. The ecological paradigm is validated in planar worlds by comparing it against the standard interface …

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Psoda: Better Tasting And Less Filling Than Paup, Hyrum Carroll, Mark J. Clement, Mark Ebbert, Quinn O. Snell Oct 2007

Psoda: Better Tasting And Less Filling Than Paup, Hyrum Carroll, Mark J. Clement, Mark Ebbert, Quinn O. Snell

Faculty Publications

PSODA is an open-source phylogenetic search application that implements traditional parsimony and likelihood search techniques as well as advanced search algorithms. PSODA is compatible with PAUP and the search algorithms are competitive with those in PAUP. PSODA also adds a basic scripting language to the PAUP block, making it possible to easily create advanced meta-searches. Additionally, PSODA provides a user-friendly GUI with real-time graphing visualizations and phylogeny viewer, and a multiple sequence alignment algorithm PSODA is freely available from the PSODA web site: http://csl.cs.byu.edu/psoda.

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Psodascript: Applying Advanced Language Constructs To Open-Source Phylogenetic Search, Hyrum Carroll, Mark J. Clement, Jonathan Krein, Quinn O. Snell, Adam R. Teichert Oct 2007

Psodascript: Applying Advanced Language Constructs To Open-Source Phylogenetic Search, Hyrum Carroll, Mark J. Clement, Jonathan Krein, Quinn O. Snell, Adam R. Teichert

Faculty Publications

Due to the immensity of phylogenetic tree space for large data sets, researches must rely on heuristic searches to infer reasonable phylogenies. By designing meta-searches which appropriately combine a variety of heuristics and parameter settings, researchers can significantly improve the performance of heuristic searches. Advanced language constructs in the open-source PSODA project—including variables, mathematical and logical expressions, conditional statements, and user-defined commands—give researchers a better framework for the exploration and exploitation of phylogenetic meta-search algorithms. PSODA’s approach to scripting meta-search algorithms is unique among open-source packages and addresses several limitations of other phylogenetic applications.

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Using Parsimony To Guide Maximum Likelihood Searches, Hyrum Carroll, Mark J. Clement, Timothy O'Connor, Quinn O. Snell, Kenneth Sundberg Oct 2007

Using Parsimony To Guide Maximum Likelihood Searches, Hyrum Carroll, Mark J. Clement, Timothy O'Connor, Quinn O. Snell, Kenneth Sundberg

Faculty Publications

The performance of maximum likelihood searches can be boosted by using the most parsimonious tree as a starting point for the search. The time spent in performing the parsimony search to find this starting tree is insignificant compared to the time spent in the maximum likelihood search, leading to an overall gain in search time. These parsimony boosted maximum likelihood searches lead to topologies with scores statisitically similar to the unboosted searches, but in less time.

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Using A Mini-Uav To Support Wilderness Search And Rescue: Practices For Human-Robot Teaming, Julie A. Adams, Brian G. Buss, Joseph L. Cooper, Michael A. Goodrich, Curtis Humphrey, Ron Zeeman Sep 2007

Using A Mini-Uav To Support Wilderness Search And Rescue: Practices For Human-Robot Teaming, Julie A. Adams, Brian G. Buss, Joseph L. Cooper, Michael A. Goodrich, Curtis Humphrey, Ron Zeeman

Faculty Publications

Wilderness Search and Rescue can benefit from aerial imagery of the search area. Mini Unmanned Aerial Vehicles can potentially provide such imagery, provided that the autonomy, search algorithms, and operator control unit are designed to support coordinated human-robot search teams. Using results from formal analyses of the WiSAR problem domain, we summarize and discuss information flow requirements for WiSAR with an eye toward the efficient use of mUAVs to support search. We then identify and discuss three different operational paradigms for performing field searches, and identify influences that affect which human-robot team paradigm is best. Since the likely location of …

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Search For Gravitational Wave Radiation Associated With The Pulsating Tail Of The Sgr 1806-20 Hyperflare Of 27 December 2004 Using Ligo, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales Sep 2007

Search For Gravitational Wave Radiation Associated With The Pulsating Tail Of The Sgr 1806-20 Hyperflare Of 27 December 2004 Using Ligo, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales

Faculty Publications

We have searched for gravitational waves (GWs) associated with the SGR 1806-20 hyperflare of 27 December 2004. This event, originating from a Galactic neutron star, displayed exceptional energetics. Recent investigations of the x-ray light curve's pulsating tail revealed the presence of quasiperiodic oscillations (QPOs) in the 30-2000 Hz frequency range, most of which coincides with the bandwidth of the LIGO detectors. These QPOs, with well-characterized frequencies, can plausibly be attributed to seismic modes of the neutron star which could emit GWs. Our search targeted potential quasimonochromatic GWs lasting for tens of seconds and emitted at the QPO frequencies. We have …

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A Utile Function Optimizer, James Carroll, Christopher K. Monson, Kevin Seppi Sep 2007

A Utile Function Optimizer, James Carroll, Christopher K. Monson, Kevin Seppi

Faculty Publications

We recast the problem of unconstrained continuous evolutionary optimization as inference in a fixed graphical model. This approach allows us to address several pervasive issues in optimization, including the traditionally difficult problem of selecting an algorithm that is most appropriate for a given task. This is accomplished by placing a prior distribution over the expected class of functions, then employing inference and intuitively defined utilities and costs to transform the evolutionary optimization problem into one of active sampling. This allows us to pose an approach to optimization that is optimal for each expressly stated function class. The resulting solution methodology …

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Parallel Pso Using Mapreduce, Andrew Mcnabb, Christopher K. Monson, Kevin Seppi Sep 2007

Parallel Pso Using Mapreduce, Andrew Mcnabb, Christopher K. Monson, Kevin Seppi

Faculty Publications

In optimization problems involving large amounts of data, such as web content, commercial transaction information, or bioinformatics data, individual function evaluations may take minutes or even hours. Particle Swarm Optimization (PSO) must be parallelized for such functions. However, large-scale parallel programs must communicate efficiently, balance work across all processors, and address problems such as failed nodes. We present MapReduce Particle Swarm Optimization (MRPSO), a PSO implementation based on the MapReduce parallel programming model. We describe MapReduce and show how PSO can be naturally expressed in this model, without explicitly addressing any of the details of parallelization. We present a benchmark …

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Inclusion Of Electrochemically Active Guests By Novel Oxacalixarene Hosts, Daniel Sobransingh, Mahender B. Dewal, Jacob Hiller, Mark D. Smith, Linda S. Shimizu Sep 2007

Inclusion Of Electrochemically Active Guests By Novel Oxacalixarene Hosts, Daniel Sobransingh, Mahender B. Dewal, Jacob Hiller, Mark D. Smith, Linda S. Shimizu

Faculty Publications

We demonstrate for the first time the utility of oxacalixarenes as hosts and investigate the forces that influence the thermodynamics of binding.

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Novel Perturbation Approach For The Structure Factor Of The Attractive Hard-Core Yukawa Fluid, Andrij Trokhymchuk, Roman Melnyk, Filip Moucka, Ivo Nezbeda Sep 2007

Novel Perturbation Approach For The Structure Factor Of The Attractive Hard-Core Yukawa Fluid, Andrij Trokhymchuk, Roman Melnyk, Filip Moucka, Ivo Nezbeda

Faculty Publications

A novel perturbation approach for the structure factor S(k) of the Lennard-Jones-type Yukawa fluid with z=1.8 is presented. An approach is based on a new reference system, that is, the short-range Yukawa model with z0 > z=1.8. By choosing for the reference system the value z0=6, it is shown that (i) the proposed approach for S(k) performs much better than the traditional hard-sphere reference perturbation method does; (ii) the use of an approximate mean spherical (MSA) description of the reference structure factor provides the results for S(k) that are more accurate as those obtained from the direct MSA computations; and (iii) …

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Mathematics Library News 2, Aaron Lercher Sep 2007

Mathematics Library News 2, Aaron Lercher

Faculty Publications

No abstract provided.

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The Contributions Of Dominic Welsh To Matroid Theory, James Oxley Sep 2007

The Contributions Of Dominic Welsh To Matroid Theory, James Oxley

Faculty Publications

Dominic Welsh began writing papers in matroid theory nearly forty years ago. Since then, he has made numerous important contributions to the subject. This chapter reviews Dominic Welsh's work in and influence on the development of matroid theory.

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