Marginalizing the likelihood function for modeled gravitational wave searches

Matched filtering is a commonly used technique in gravitational wave searches for signals from compact binary systems and from rapidly rotating neutron stars. A common issue in these searches is dealing with four extrinsic parameters which do not affect the phase evolution of the system: the overall amplitude, initial phase, and two angles determining the overall orientation of the system. The F-statistic maximizes the likelihood function analytically over these parameters, while the B-statistic marginalizes over them. The B-statistic, while potentially more powerful and capable of incorporating astrophysical priors, is not as widely used because of the computational difficulty of performing the marginalization. In this paper we address this difficulty and show how the marginalization can be done analytically by combining the four parameters into a set of complex amplitudes. The results of this paper are applicable to both transient non-precessing binary coalescence events, and to long lived signals from rapidly rotating neutron stars.Comment: 26 page

Antecedents and Effect of IT Usage on Performance: A Research Framework and Empirical Study

Information Technology (IT) Usage is an important construct in Information Systems research. While the relationshipbetween IT Usage and Performance is well studied along with the antecedents of IT Usage, extant research has not yet fullyexplored an integrated model of IT Usage, its antecedents and impact on performance. In this paper, we propose an integratedtheoretical framework for such an effort. We detail our preliminary results for a section of the theoretical model todemonstrate the viability of the research model. We find that for our research context, the preliminary results align well withtheoretical predictions. We show strong statistical relationships between actual IT Usage and performance at the business unitlevel in both cross sectional and panel data analysis. We conclude by discussing the proposed data collection and analysisapproach for testing the integrated theoretical framework for the relationship between IT Usage, its antecedents and impacton performance

How Client Capabilities, Vendor Configuration and Location Impact BPO Outcomes

Despite the increasing use of onshore and offshore business process outsourcing (BPO), a comprehensive literature review [38] finds that there has been limited empirical research on BPO outcomes. This article responds to the call for research by developing and testing a conceptual model for BPO outcomes using data from 50 firms publicly traded in the U.S., including 38 firms in the Forbes Global 2000. We find that client firm capabilities, vendor configuration, and country location lead to interesting tradeoffs in the BPO quality, cost, and time outcomes. For example, while multi-sourcing offers advantages such as risk mitigation, client firms encounter reduced BPO time benefits when they use multiple vendors. While onshore BPO can lead to an improved quality, higher onshore labor costs result in lower BPO cost savings. And while offshore destinations such as India offer lower labor costs, time zone differences lead to reduced BPO time benefits

Simulation of Particle Impact with a Wedge in Dilute Two-phase Flow

Dilute solid-fluid flow over a wedge in a stationary channel is numerically solved using one-way coupling between fluid and solid particles. The two-dimensional, steady, laminar carrierphaseflow is determined by Galerkin finite-element method using Newton's iteration for primitive variables, pressure, and velocity. Velocity is interpolated biquadratically and pressure is interpolated linearly. Parameter continuation is used to compute solutions for relatively large values of flow Reynolds number. Individual particles are tracked from specified inlet positionsby a fourth-order Runge-Kutta method applied to the equations of motion ofthe particle. Forces acting on the particle include drag, pressure, and inertia. Forces due to particle-particle interaction and Basset forces are neglected. Collisions with the wedge and the walls of the channel are modelled via assumed coefficients ofrestitution in both the normal and the tangential directions. The point of actual impact is determined by interpolation. Results are presented for various parameters, such as particle diameter, wedge angle, Reynolds number, particle density, etc

Object-Oriented Implementation of the NAS Parallel Benchmarks using Charm++

This report describes experiences with implementing the NAS Computational Fluid Dynamics benchmarks using a parallel object-oriented language, Charm++. Our main objective in implementing the NAS CFD kernel benchmarks was to develop a code that could be used to easily experiment with different domain decomposition strategies and dynamic load balancing. We also wished to leverage the object-orientation provided by the Charm++ parallel object-oriented language, to develop reusable abstractions that would simplify the process of developing parallel applications. We first describe the Charm++ parallel programming model and the parallel object array abstraction, then go into detail about each of the Scalar Pentadiagonal (SP) and Lower/Upper Triangular (LU) benchmarks, along with performance results. Finally we conclude with an evaluation of the methodology used

Effect of electron beam irradiation on structural and optical properties of Cu-doped In2O3 films prepared by RF magnetron sputtering.

Undoped and Cu-doped In2O3 films were prepared by radiofrequency magnetron sputtering technique. The effects of Cu doping and high-energy electron beam irradiation on the structural and optical properties of as-prepared films were investigated using techniques such as x-ray diffraction, x-ray photoelectron spectroscopy (XPS), lateral scanning electron microscopic image analysis, energy-dispersive x-ray (EDX) spectroscopy, micro-Raman, and ultraviolet-visible (UV-vis) spectroscopy. Moderate doping of Cu in In2O3 enhanced the intensity of (222) peak, indicating alignment of crystalline grains along . Electron beam irradiation promoted orientation of crystalline grains along in undoped and moderately Cu-doped films. EDX spectroscopic and XPS analyses revealed incorporation of Cu2+ ions in the lattice. The transmittance of Cu-doped films decreased with e-beam irradiation. Systematic reduction of the bandgap energy with an increase in Cu doping concentration was seen in unirradiated and electron-beam-irradiated films

Manufacturing practices for silicon-based power diode in fast recovery applications

This paper reports a fast recovery semiconductor diode that was developed for use in high power applications. The diode constructed in disc-type ceramic package with a peak-inverse voltage rating of 2800 V and current rating of 710 A was fabricated using float-zone (FZ) silicon wafer as the starting raw material. Alternate processes viz. gold diffusion, gamma irradiation and electron irradiation were explored for control of carrier lifetime required to tune the switching response of the diode to the desired value of 8 s. The paper compares the results of these alternate processes. The diodes were fabricated and tested for forward conduction, reverse blocking and switching characteristics. The measured values were observed to be comparable with the design requirements. The paper presents an overview of the design, manufacturing nd testing practices adopted to meet the desired diode characteristics and ratings. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2788

The cross-correlation search for periodic gravitational waves

In this paper we study the use of cross-correlations between multiple gravitational wave (GW) data streams for detecting long-lived periodic signals. Cross-correlation searches between data from multiple detectors have traditionally been used to search for stochastic GW signals, but recently they have also been used in directed searches for periodic GWs. Here we further adapt the cross-correlation statistic for periodic GW searches by taking into account both the non-stationarity and the long term-phase coherence of the signal. We study the statistical properties and sensitivity of this search, its relation to existing periodic wave searches, and describe the precise way in which the cross-correlation statistic interpolates between semi-coherent and fully-coherent methods. Depending on the maximum duration over we wish to preserve phase coherence, the cross-correlation statistic can be tuned to go from a standard cross-correlation statistic using data from distinct detectors, to the semi-coherent time-frequency methods with increasing coherent time baselines, and all the way to a full coherent search. This leads to a unified framework for studying periodic wave searches and can be used to make informed trade-offs between computational cost, sensitivity, and robustness against signal uncertainties.Comment: 17 pages, 1 figure, RevTeX

Effect of electron irradiation on the properties of CdTe/CdS solar cells

Abstract Polycrystalline CdTe/CdS solar cells are used in space, as well as terrestrial, applications. The results of the studies on the effect of 8 MeV electron irradiation on p-CdTe/n-CdS thin film solar cells prepared by radio frequency (RF) sputtering are presented in this article. Solar cell parameters like short circuit current (I sc ), open circuit voltage (V oc ), fill factor (FF), conversion efficiency (Z), saturation current (I s ) and ideality factor (n) have been considered. CdTe thin film solar cells exhibit good stability against electron irradiation up to 100 kGy.