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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Generalized Spectral Analysis for Large Sets of Approval Voting Data

Uminsky, David 01 May 2003 (has links)
Generalized Spectral analysis of approval voting data uses representation theory and the symmetry of the data to project the approval voting data into orthogonal and interpretable subspaces. Unfortunately, as the number of voters grows, the data space becomes prohibitively large to compute the decomposition of the data vector. To attack these large data sets we develop a method to partition the data set into equivalence classes, in order to drastically reduce the size of the space while retaining the necessary characteristics of the data set. We also make progress on the needed statistical tools to explain the results of the spectral analysis. The standard spectral analysis will be demonstrated, and our partitioning technique is applied to U.S. Senate roll call data.

Three Essays on Spectral Analysis and Dynamic Factors

Liska, Roman 10 September 2008 (has links)
The main objective of this work is to propose new procedures for the general dynamic factor analysis introduced by Forni et al. (2000). First, we develop an identification method for determining the number of common shocks in the general dynamic factor model. Sufficient conditions for consistency of the criterion are provided for large n (number of series) and T (the series length). We believe that our procedure can shed light on the ongoing debate on the number of factors driving the US or Eurozone economy. Second, we show how the dynamic factor analysis method proposed in Forni et al. (2000), combined with our identification method, allows for identifying and estimating joint and block-specific common factors. This leads to a more sophisticated analysis of the structures of dynamic interrelations within and between the blocks in suchdatasets. Besides the framework of the general dynamic factor model we also propose a consistent lag window spectral density estimator based on multivariate M-estimators by Maronna (1976) when the underlying data are coming from the alpha mixing stationary Gaussian process.

Role of Glutamatergic Neurotransmission at the Nucleus Reticularis Ventrolateralis during Experimental Endotoxemia

Chang, Pi-Shan 26 June 2001 (has links)
The components of SAP signals of low- frequency (LF: 0.08-0.15 Hz) and very low- frequency (VLF: 0.00-0.08 Hz) related with vasomotor tone that reflects the activity of sympathetic premotor neuron in the nucleus reticularis ventrolateralis (NRVL). The Sprague-Dawely male rats with acute endotoxemia (lipopolysaccharide, LPS; 15 mg/Kg i.v.) induced a reduction phase (phase¢¹), followed by partial recovery (phase¢º) and a secondary decrease (phase ¢»). The rats with acute endotoxemia display three phases based on change in the power density of LF and VLF component. Pretreatment with microinjection of NMDA receptor antagonist, MK-801, and non-NMDA receptor antagonist, CNQX into the bilaterial NRVL prolong the survival time and prolong the duration time of phase¢º and phase¢». Pretreatment with high concentration MK-801 (200 pmol) and CNQX (10 pmol) hold the MSAP and heart rate in the steady state and decrease the slope of MSAP falling during endotoxemia.The power density of pretreatment with high concentration MK-801 (200 pmol) and CNQX (10 pmol) was deceease. We conclude that the rat during experimental endotoxemia decrease the duration time of NMDA and non-NMDA receptor activity in NRVL. The NMDA receptor and non-NMDA receptor activity in NRVL during endotoxemia contribute the slope of MSAP falling and cause to death.

Vanishing properties and spectral analysis in the Kerzman-Stein theory /

January 2001 (has links)
Thesis (Ph. D.)--University of Chicago, Dept. of Mathematics, June 2001. / Includes bibliographical references. Also available on the Internet.

Spectroscopic studies of coal and an ESR study of mono and dicarbonyl radical cations

Portwood, Lynn January 1987 (has links)
Part I - ESR spectra of pure coals, oils and tars are presented; their g values and linewidths are calculated. Almost all the spectra are single, broad resonances; but one coal, Hucknall Coal, exhibits a two line spectrum, a narrow line superimposed on a broad line. On admission of oxygen the narrow line is reversibly lost. On the addition of various solvents to the samples, in most cases, an irreversible loss in ESR signal intensity was observed. There seems to be no direct correlation between which solvent is added to which coal and the effect on the ESR signal intensity. Infra-red spectra of pure coals are studied, both as pressed discs and thin films, and a method for the preparation of these discs and films is given. Solvent addition experiments were undertaken and the results show the breaking of weak coal/water hydrogen bonds and the formation of stronger coal/solvent hydrogen bonds. Part II - ESR spectra of the radical cations of several mono and dicarbonyl compounds are presented and interpretation of these spectra are given. For most compounds the parent radical cation is seen, with the spin on oxygen. The cyclic dicarbonyls show the σ-bonded structure for the cation with coupling to the protons δ to the spin. Some non-aldehydic dicarbonyls show a rearranged structure with the spin on carbon. The aldehydic dicarbonyls all show, in addition to the parent radical cation, lines due to an acetal type species, as yet unidentified. Some compounds containing nitrogen or sulphur in addition to oxygen have the spin localised onto these alternative heteroatoms.

Energy transfer studies in polymer and dye scintillator systems

Hutton, Barbara January 1994 (has links)
No description available.

Asymptotics for the solution of the Schrödinger equation

Al-Naggar, Ibtesam M. Abu-Sulayman January 1994 (has links)
No description available.

Optimisation of the inductively-coupled plasma for the analysis of solutions and slurries

Norman, Philip January 1987 (has links)
The application of inductively-coupled plasma (ICP) spectrometry for the analysis of solutions and slurries is reviewed. The critical parameters which affect analytical performance are identified and methods for the optimisation of the ICP for such applications demonstrated. Particle size of the suspended sample is shown to be the most important factor in the analysis of slurry samples. It is demonstrated that only particles less than 8 um in diameter reach the plasma even when the maximal diameter injector tube (3 mm i.d.) is used. Accordingly various methods for the reduction of particle size have been investigated and milling shown to be the preferable approach. A low cost method using blown zirconia spheres in a screw-cap plastic bottle agitated on a flask shaker was developed. Using this method it proved possible to analyse a wide variety of solid samples using slurry atomisation using both ICP- atomic emission spectrometry (ICP-AES) and ICP-mass spectrometry (ICP-MS) with aqueous calibration. Results are presented for the elemental analysis of certified reference material (CRM) soils, catalyst samples, a zeolite, titanium dioxide, P.T.F.E. powder, and unfiltered natural waters by slurry atomisation ICP-AES. Comparison by other techniques showed excellent accuracy for major, minor and trace elements and equivalent precision to solution analysis. The CRM soils, catalysts and the zeolite were also analysed by ICP-MS using slurry atomisation with similar success and enhanced accuracy at the trace level. Aluminium proved to be an exception and generally low recoveries (80-90%) were observed for this element using slurry atomisation. Finally the uses of the simplex optimisation algorithm to improve analytical performance, particularly in ICP-AES, is discussed. A computer program to facilitate the use of simplex optimisation for a variety of instrumentation was written and its use in three different analytical techniques demonstrated. The necessary hardware and software modifications to a commercially available ICP spectrometer to enable automated simplex optimisation are described. The prospects for such intelligent self-optimising instrumentation are discussed as is the potential extension of the application of slurry analysis by ICP-AES and ICP-MS.

VLSI implementation of an efficient method for the computation of line spectral frequencies /

Reynolds, David L. January 2004 (has links)
Thesis (M.S.)--Rowan University, 2004. / Typescript. Includes bibliographical references.

Continuous real-time recovery of optical spectral features distorted by fast-chirped readout

Bekker, Scott Henry. January 2006 (has links) (PDF)
Thesis (M.S.)--Montana State University--Bozeman, 2006. / Typescript. Chairperson, Graduate Committee: Ross K. Snider. Includes bibliographical references (leaves 101-102).

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