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Parallel computation of automatic differentiation applied to magnetic field calculations

Description: The author presents a parallelization of an accelerator physics application to simulate magnetic field in three dimensions. The problem involves the evaluation of high order derivatives with respect to two variables of a multivariate function. Automatic differentiation software had been used with some success, but the computation time was prohibitive. The implementation runs on several platforms, including a network of workstations using PVM, a MasPar using MPFortran, and a CM-5 using CMFortran. A careful examination of the code led to several optimizations that improved its serial performance by a factor of 8.7. The parallelization produced further improvements, especially on the MasPar with a speedup factor of 620. As a result a problem that took six days on a SPARC 10/41 now runs in minutes on the MasPar, making it feasible for physicists at Lawrence Berkeley Laboratory to simulate larger magnets.
Date: September 1, 1994
Creator: Hinkins, R. L.
Partner: UNT Libraries Government Documents Department

Exploring phase space concepts in the forecasting of time series with artificial neural networks

Description: The authors study the performance of feedforward artificial neural networks in forecasting future values of several different time series. They explore both short- and long-term prediction of several periodic time series. They find that a significant source of error in long-term prediction of time series is introduced by a phase shift between the network output and the time series. They explore the origin of this phase shift and suggest strategies for minimizing its effect. They find that the phase diagrams of the time series and the neural network forecast contain useful diagnostic information.
Date: September 13, 1993
Creator: Rogers, R. D. & Vemuri, V.
Partner: UNT Libraries Government Documents Department

Control of DWPF (Defense Waste Processing Facility) melter feed composition

Description: The Defense Waste Processing Facility will be used to immobilize Savannah River Site high-level waste into a stable borosilicate glass for disposal in a geologic repository. Proper control of the melter feed composition in this facility is essential to the production of glass which meets product durability constraints dictated by repository regulations and facility processing constraints dictated by melter design. A technique has been developed which utilizes glass property models to determine acceptable processing regions based on the multiple constraints imposed on the glass product and to display these regions graphically. This system along with the batch simulation of the process is being used to form the basis for the statistical process control system for the facility. 13 refs., 3 figs., 1 tab.
Date: January 1, 1990
Creator: Edwards, R.E. Jr.; Brown, K.G. & Postles, R.L.
Partner: UNT Libraries Government Documents Department

Statistical techniques applied to aerial radiometric surveys (STAARS): principal components analysis user's manual. [NURE program]

Description: A Principal Components Analysis (PCA) has been written to aid in the interpretation of multivariate aerial radiometric data collected by the US Department of Energy (DOE) under the National Uranium Resource Evaluation (NURE) program. The variations exhibited by these data have been reduced and classified into a number of linear combinations by using the PCA program. The PCA program then generates histograms and outlier maps of the individual variates. Black and white plots can be made on a Calcomp plotter by the application of follow-up programs. All programs referred to in this guide were written for a DEC-10. From this analysis a geologist may begin to interpret the data structure. Insight into geological processes underlying the data may be obtained.
Date: January 1, 1981
Creator: Koch, C.D.; Pirkle, F.L. & Schmidt, J.S.
Partner: UNT Libraries Government Documents Department

Multivariate optimization of production systems: The time dimension

Description: Traditional analysis of oil and gas production systems treats individual nodes one at a time. This only calculates a feasible solution which is not necessarily optimal. Multivariate optimization is able to determine the most profitable configuration, including all variables simultaneously. The optimization can also find the optimal recovery over a period of time, rather than just at a single instant as in traditional methods. This report describes the development of multivariate optimization for situations in which the decision variables may change as a function of time. For example, instead of estimating a tubing size which is optimal over the life of the project, this approach determines a series of optimal tubing sizes which may change from year to year. Examples show that under an optimal strategy, tubing size can be changed only infrequently while still increasing profitability of a project. The methods used in this work considered the special requirements of objectives which are not smooth functions of their decision variables. The physical problems considered included artificial lift production systems.
Date: April 1, 1993
Creator: Ravindran, N. & Horne, R.N.
Partner: UNT Libraries Government Documents Department

1987 wet deposition temporal and spatial patterns in North America

Description: The focus of this report is on North American wet deposition temporal patterns from 1979 to 1987 and spatial patterns for 1987. The report investigates the patterns of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. Data are from the Acid Deposition System (ADS) for the statistical reporting of North American deposition data which includes the National Atmospheric Deposition Program/National Trends Network (NADP/NTN), the MAP3S precipitation chemistry network, the Utility Acid Precipitation Study Program (UAPSP), the Canadian Precipitation Monitoring Network (CAPMoN), and the daily and 4-weekly Acidic Precipitation in Ontario Study (APIOS-D and APIOS-C). Mosaic maps, based on surface estimation using kriging, display concentration and deposition spatial patterns of pH, hydrogen, sulfate, nitrate, ammonium, and calcium ion species for 1987 annual, winter, and summer periods. The temporal pattern analyses use a subset of 39 sites over a 9-year (1979--1987) period and an expanded subset of 140 sites with greater spatial coverage over a 6-year (1982--1987) period. 68 refs., 15 figs., 15 tabs.
Date: March 1, 1990
Creator: Simpson, J.C. & Olsen, A.R.
Partner: UNT Libraries Government Documents Department

Investigation of an empirical probability measure based test for multivariate normality

Description: Foutz (1980) derived a goodness of fit test for a hypothesis specifying a continuous, p-variate distribution. The test statistic is both distribution-free and independent of p. In adapting the Foutz test for multivariate normality, we consider using chi/sup 2/ and rescaled beta variates in constructing statistically equivalent blocks. The Foutz test is compared to other multivariate normality tests developed by Hawkins (1981) and Malkovich and Afifi (1973). The set of alternative distributions tested include Pearson type II and type VII, Johnson translations, Plackett, and distributions arising from Khintchine's theorem. Univariate alternatives from the general class developed by Johnson et al. (1980) were also used. An empirical study confirms the independence of the test statistic on p even when parameters are estimated. In general, the Foutz test is less conservative under the null hypothesis but has poorer power under most alternatives than the other tests.
Date: January 1, 1984
Creator: Booker, J.M.; Johnson, M.E. & Beckman, R.J.
Partner: UNT Libraries Government Documents Department

Geochemical and physical properties of soils and shallow sediments at the Savannah River Site

Description: A program to characterize the geochemical and physical properties of the unimpacted soils and shallow sediments at the Savannah River Site (SRS) has been completed. The maximum, minimum, median, standard deviation, and mean values for metals, radionuclides, inorganic anions, organic compounds, and agricultural indicator parameters are summarized for six soil series that were identified as representative of the 29 soil series at SRS. The soils from unimpacted areas of SRS are typical of soils found in moderately aggressive weathering environments, including the southeastern United States. Appendix 8 organic compounds were detected in all samples. Since these constituents are not generally present in soil, this portion of the investigation was intended to assess possible laboratory artifacts. An additional objective of the SRS Soil Study was to determine if the composition of the split spoon sampler biased chemical analysis of the soils. Twenty-five duplicate samples were analyzed for a number of metals, radiological and agricultural parameters, and organics by two laboratories currently contracted with to analyze samples during waste site characterization. In all cases, the absolute values of the average differences are relatively small compared to the overall variability in the population. 31 refs., 14 figs., 48 tabs.
Date: August 31, 1990
Creator: Looney, B.B.; Eddy, C.A.; Ramdeen, M.; Pickett, J. (Savannah River Lab., Aiken, SC (USA)); Rogers, V. (Soil Conservation Service, Aiken, SC (USA). Savannah River Site Savannah River Lab., Aiken, SC (USA)); Scott, M.T. et al.
Partner: UNT Libraries Government Documents Department

The comparative uptake and interaction of several radionuclides in the trophic levels surrounding the Los Alamos Meson Physics Facility (LAMPF) waste water ponds

Description: A study was undertaken to examine the uptake, distribution, and interaction of five activation products (Co-57, Be-7, Cs-134, Rb-83, and Mn-54) within the biotic and abiotic components surrounding the waste treatment lagoons of the Los Alamos Meson Physics Facility (LAMPF). The study attempted to ascertain where, and what specific interactions were taking place among the isotopes and the biotic/abiotic components. A statistical approach, utilizing Multivariate Analysis of Variance (MANOVA), was conducted testing the radioisotopic concentrations by (1) the trophic levels (TROPLVL) in each position sampled on the grid, (2) where sampled on the grid (TRAN), (3) where sampled with-in each grid line (PLOT), and (4) the side with which sampled (SIDE). This provided both the dependent and independent variables that would be tested. The Null Hypothesis (Ho) tested the difference in the mean values of the isotopes within/between each of the four independent variables. The Rb-83 statistic indicated an accumulation within the TRAN and PLOT variables within the sampled area. The Co-57 test statistic provided a value which indicated that accumulation of this isotope within TROPLVL was taking place. Mn-54 test values indicated that accumulation was also taking place at the higher trophic levels within the PLOT, TRAN, and SIDE positions. Cs-134 was found to accumulate to third level in this trophic level structure (TROPLVL-(vegetation)), and then decrease from there. The Be-7 component provided no variance from known compartmental transfers. 210 refs., 17 figs., 4 tabs.
Date: August 1, 1989
Creator: Brooks, G.H. Jr.
Partner: UNT Libraries Government Documents Department

Modeling and generating input processes

Description: This tutorial paper provides information relevant to the selection and generation of stochastic inputs to simulation studies. The primary area considered is multivariate but much of the philosophy at least is relevant to univariate inputs as well. 14 refs.
Date: January 1, 1987
Creator: Johnson, M.E.
Partner: UNT Libraries Government Documents Department

A method for evaluating the effectiveness of site characterization measurements

Description: A quantitative approach for evaluating the effectiveness of site characterization measurement activities is developed and illustrated with an example application to hypothetical measurement schemes at a potential geologic repository site for radioactive waste. The method is a general one and could also be applied at sites for underground disposal of hazardous chemicals. The approach presumes that measurements will be undertaken to support predictions of the performance of some aspect of a constructed facility or natural system. It requires a quantitative performance objective, such as groundwater travel time or contaminant concentration, against which to compare predictions of performance. The approach recognizes that such predictions are uncertain because the measurements upon which they are based are uncertain. The effectiveness of measurement activities is quantified by a confidence index, ..beta.., that reflects the number of standard deviations separating the best estimate of performance from the predetermined performance objective. Measurements that reduce the uncertainty in predictions lead to increased values of ..beta... 5 refs., 4 figs.
Date: January 1, 1987
Creator: Ditmars, J.D.
Partner: UNT Libraries Government Documents Department

Stepwise Calculation for the Determination of the Number of Transfer Units in Countercurrent Extraction Columns

Description: Report discussing a method for the stepwise calculation of the number of transfer units utilized in a given solvent extraction operation. "Use of the method results in a very appreciable saving in time of calculation with an error of 1.5% for the runs tested. The error tends to become smaller with increasing total numbers of transfer units involved."
Date: September 12, 1949
Creator: Burns, W. A. & Eschbach, E. A.
Partner: UNT Libraries Government Documents Department

Multivariable and distributed control of nonlinear chemical processes using adaptive methods

Description: In this work we studied the application of adaptive learning and optimization to chemical process control. The work covered theory as well as practical applications of adaptive and nonlinear control, including multivariable periodic control The main findings were: 1. Linear adaptive control systems may display chaotic behavior. The chaos has small amplitude if the algorithm is properly implemented. 2. Stability theory for nonlinear adaptive control has been developed. 3. Experimental evaluation of predictive control was performed. 4. A theory for periodic control and adaptive periodic control of chemical processes was developed.
Date: January 1, 1988
Creator: Ydstie, B.E.
Partner: UNT Libraries Government Documents Department

Multivariate methods in nuclear waste remediation: Needs and applications

Description: The United States Department of Energy (DOE) has developed a strategy for nuclear waste remediation and environmental restoration at several major sites across the country. Nuclear and hazardous wastes are found in underground storage tanks, containment drums, soils, and facilities. Due to the many possible contaminants and complexities of sampling and analysis, multivariate methods are directly applicable. However, effective application of multivariate methods will require greater ability to communicate methods and results to a non-statistician community. Moreover, more flexible multivariate methods may be required to accommodate inherent sampling and analysis limitations. This paper outlines multivariate applications in the context of select DOE environmental restoration activities and identifies several perceived needs.
Date: May 1, 1992
Creator: Pulsipher, B.A.
Partner: UNT Libraries Government Documents Department

Distribution selection in statistical simulation studies

Description: The statistics profession has been remiss in exploiting the numerous advances in simulation methodology. The purpose of this article is to outline progress in variate generation relevant to the conduct of statistical simulation studies. The emphasis is on multivariate distributions, a thriving area of research. 11 refs.
Date: January 1, 1986
Creator: Johnson, M.E.
Partner: UNT Libraries Government Documents Department

Identification of multivariate linear systems

Description: Multivariate identification problems are treated with a least-squares approach. A chapter on scalar problems focuses attention on the classical parameter-estimate bias problem caused by measurement noise and develops a straightforward and effective way to remove the bias. A chapter on multivariate problems generalizes the bias removal method and develops a form selection procedure. The form selection procedure generally ensures more accurate identification than is possible with identification methods which rely on a fixed form. The concept of a form selection procedure is new to this work. A results chapter presents four example problems. Each example illustrates specific features of the identification technique. As a collection the examples emphasize the complexity of system identification and demonstrate that identification techniques will perform well when carefully applied.
Date: April 1, 1982
Creator: Griffith, J.M.
Partner: UNT Libraries Government Documents Department

An Application of Multivariate Statistical Analysis for Query-Driven Visualization

Description: Abstract?Driven by the ability to generate ever-larger, increasingly complex data, there is an urgent need in the scientific community for scalable analysis methods that can rapidly identify salient trends in scientific data. Query-Driven Visualization (QDV) strategies are among the small subset of techniques that can address both large and highly complex datasets. This paper extends the utility of QDV strategies with a statistics-based framework that integrates non-parametric distribution estimation techniques with a new segmentation strategy to visually identify statistically significant trends and features within the solution space of a query. In this framework, query distribution estimates help users to interactively explore their query's solution and visually identify the regions where the combined behavior of constrained variables is most important, statistically, to their inquiry. Our new segmentation strategy extends the distribution estimation analysis by visually conveying the individual importance of each variable to these regions of high statistical significance. We demonstrate the analysis benefits these two strategies provide and show how they may be used to facilitate the refinement of constraints over variables expressed in a user's query. We apply our method to datasets from two different scientific domains to demonstrate its broad applicability.
Date: March 1, 2010
Creator: Gosink, Luke J.; Garth, Christoph; Anderson, John C.; Bethel, E. Wes & Joy, Kenneth I.
Partner: UNT Libraries Government Documents Department

Automated detection and analysis of particle beams in laser-plasma accelerator simulations

Description: Numerical simulations of laser-plasma wakefield (particle) accelerators model the acceleration of electrons trapped in plasma oscillations (wakes) left behind when an intense laser pulse propagates through the plasma. The goal of these simulations is to better understand the process involved in plasma wake generation and how electrons are trapped and accelerated by the wake. Understanding of such accelerators, and their development, offer high accelerating gradients, potentially reducing size and cost of new accelerators. One operating regime of interest is where a trapped subset of electrons loads the wake and forms an isolated group of accelerated particles with low spread in momentum and position, desirable characteristics for many applications. The electrons trapped in the wake may be accelerated to high energies, the plasma gradient in the wake reaching up to a gigaelectronvolt per centimeter. High-energy electron accelerators power intense X-ray radiation to terahertz sources, and are used in many applications including medical radiotherapy and imaging. To extract information from the simulation about the quality of the beam, a typical approach is to examine plots of the entire dataset, visually determining the adequate parameters necessary to select a subset of particles, which is then further analyzed. This procedure requires laborious examination of massive data sets over many time steps using several plots, a routine that is unfeasible for large data collections. Demand for automated analysis is growing along with the volume and size of simulations. Current 2D LWFA simulation datasets are typically between 1GB and 100GB in size, but simulations in 3D are of the order of TBs. The increase in the number of datasets and dataset sizes leads to a need for automatic routines to recognize particle patterns as particle bunches (beam of electrons) for subsequent analysis. Because of the growth in dataset size, the application of machine learning techniques for ...
Date: May 21, 2010
Creator: Ushizima, Daniela Mayumi; Geddes, C.G.; Cormier-Michel, E.; Bethel, E. Wes; Jacobsen, J.; Prabhat, , et al.
Partner: UNT Libraries Government Documents Department

Chemometric and Statistical Analyses of ToF-SIMS Spectra of Increasingly Complex Biological Samples

Description: Characterizing and classifying molecular variation within biological samples is critical for determining fundamental mechanisms of biological processes that will lead to new insights including improved disease understanding. Towards these ends, time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to examine increasingly complex samples of biological relevance, including monosaccharide isomers, pure proteins, complex protein mixtures, and mouse embryo tissues. The complex mass spectral data sets produced were analyzed using five common statistical and chemometric multivariate analysis techniques: principal component analysis (PCA), linear discriminant analysis (LDA), partial least squares discriminant analysis (PLSDA), soft independent modeling of class analogy (SIMCA), and decision tree analysis by recursive partitioning. PCA was found to be a valuable first step in multivariate analysis, providing insight both into the relative groupings of samples and into the molecular basis for those groupings. For the monosaccharides, pure proteins and protein mixture samples, all of LDA, PLSDA, and SIMCA were found to produce excellent classification given a sufficient number of compound variables calculated. For the mouse embryo tissues, however, SIMCA did not produce as accurate a classification. The decision tree analysis was found to be the least successful for all the data sets, providing neither as accurate a classification nor chemical insight for any of the tested samples. Based on these results we conclude that as the complexity of the sample increases, so must the sophistication of the multivariate technique used to classify the samples. PCA is a preferred first step for understanding ToF-SIMS data that can be followed by either LDA or PLSDA for effective classification analysis. This study demonstrates the strength of ToF-SIMS combined with multivariate statistical and chemometric techniques to classify increasingly complex biological samples. Applying these techniques to information-rich mass spectral data sets opens the possibilities for new applications including classification of subtly different biological samples that ...
Date: October 24, 2007
Creator: Berman, E S; Wu, L; Fortson, S L; Nelson, D O; Kulp, K S & Wu, K J
Partner: UNT Libraries Government Documents Department

Final report : multicomponent forensic signature development : interactions with common textiles; mustard precursors and simulants.

Description: 2-Chloroethyl phenyl sulfide (CEPS), a surrogate compound of the chemical warfare agent sulfur mustard, was examined using thermal desorption coupled gas chromatography-mass spectrometry (TD/GC-MS) and multivariate analysis. This work describes a novel method of producing multiway data using a stepped thermal desorption. Various multivariate analysis schemes were employed to analyze the data. These methods may be able to discern different sources of CEPS. In addition, CEPS was applied to cotton, nylon, polyester, and silk swatches. These swatches were placed in controlled humidity chambers maintained at 23%, 56%, and 85% relative humidity. At regular intervals, samples were removed from each test swatch, and the samples analyzed using TD/GC-MS. The results were compared across fabric substrate and humidity.
Date: February 1, 2010
Creator: Van Benthem, Mark Hilary; Mowry, Curtis Dale; Kotula, Paul Gabriel & Borek, Theodore Thaddeus, III
Partner: UNT Libraries Government Documents Department

Single top quark production and Vtb at the Tevatron

Description: Single top quark production via the electroweak interaction was observed by the D0 and CDF collaborations at the Tevatron proton-antiproton collider at Fermilab. Multivariate analysis techniques are employed to extract the small single top quark signal. The combined Tevatron cross section is 2.76{sub -0.47}{sup +0.58} pb. This corresponds to a lower limit on the CKM matrix element |V{sub tb}| of 0.77. Also reported are measurements of the t-channel cross section, the top quark polarization in single top quark events, and limits on gluon-quark flavor-changing neutral currents and W{prime} boson production.
Date: September 1, 2010
Creator: Schwienhorst, Reinhard & U., /Michigan State
Partner: UNT Libraries Government Documents Department

Multivariate analysis of progressive thermal desorption coupled gas chromatography-mass spectrometry.

Description: Thermal decomposition of poly dimethyl siloxane compounds, Sylgard{reg_sign} 184 and 186, were examined using thermal desorption coupled gas chromatography-mass spectrometry (TD/GC-MS) and multivariate analysis. This work describes a method of producing multiway data using a stepped thermal desorption. The technique involves sequentially heating a sample of the material of interest with subsequent analysis in a commercial GC/MS system. The decomposition chromatograms were analyzed using multivariate analysis tools including principal component analysis (PCA), factor rotation employing the varimax criterion, and multivariate curve resolution. The results of the analysis show seven components related to offgassing of various fractions of siloxanes that vary as a function of temperature. Thermal desorption coupled with gas chromatography-mass spectrometry (TD/GC-MS) is a powerful analytical technique for analyzing chemical mixtures. It has great potential in numerous analytic areas including materials analysis, sports medicine, in the detection of designer drugs; and biological research for metabolomics. Data analysis is complicated, far from automated and can result in high false positive or false negative rates. We have demonstrated a step-wise TD/GC-MS technique that removes more volatile compounds from a sample before extracting the less volatile compounds. This creates an additional dimension of separation before the GC column, while simultaneously generating three-way data. Sandia's proven multivariate analysis methods, when applied to these data, have several advantages over current commercial options. It also has demonstrated potential for success in finding and enabling identification of trace compounds. Several challenges remain, however, including understanding the sources of noise in the data, outlier detection, improving the data pretreatment and analysis methods, developing a software tool for ease of use by the chemist, and demonstrating our belief that this multivariate analysis will enable superior differentiation capabilities. In addition, noise and system artifacts challenge the analysis of GC-MS data collected on lower cost equipment, ubiquitous in commercial laboratories. ...
Date: September 1, 2010
Creator: Van Benthem, Mark Hilary; Mowry, Curtis Dale; Kotula, Paul Gabriel & Borek, Theodore Thaddeus, III
Partner: UNT Libraries Government Documents Department


Description: Model and experimental estimates of the Multi-Isotope Process Monitor performance for determining burnup after dissolution and acid concentration during solvent extraction steps during reprocessing of spent nuclear fuel are presented.
Date: October 18, 2009
Creator: Schwantes, Jon M.; Orton, Christopher R.; Fraga, Carlos G.; Christensen, Richard; Laspe, Amy R. & Ward, Rebecca M.
Partner: UNT Libraries Government Documents Department

Decreased expression of RNA interference machinery, Dicer and Drosha, is associated with poor outcome in ovarian cancer patients

Description: The clinical and functional significance of RNA interference (RNAi) machinery, Dicer and Drosha, in ovarian cancer is not known and was examined. Dicer and Drosha expression was measured in ovarian cancer cell lines (n=8) and invasive epithelial ovarian cancer specimens (n=111) and correlated with clinical outcome. Validation was performed with previously published cohorts of ovarian, breast, and lung cancer patients. Anti-Galectin-3 siRNA and shRNA transfections were used for in vitro functional studies. Dicer and Drosha mRNA and protein levels were decreased in 37% to 63% of ovarian cancer cell lines and in 60% and 51% of human ovarian cancer specimens, respectively. Low Dicer was significantly associated with advanced tumor stage (p=0.007), and low Drosha with suboptimal surgical cytoreduction (p=0.02). Tumors with both high Dicer and Drosha were associated with increased median patient survival (>11 years vs. 2.66 years for other groups; p<0.001). In multivariate analysis, high Dicer (HR=0.48; p=0.02), high-grade histology (HR=2.46; p=0.03), and poor chemoresponse (HR=3.95; p<0.001) were identified as independent predictors of disease-specific survival. Findings of poor clinical outcome with low Dicer expression were validated in separate cohorts of cancer patients. Galectin-3 silencing with siRNA transfection was superior to shRNA in cell lines with low Dicer (78-95% vs. 4-8% compared to non-targeting sequences), and similar in cell lines with high Dicer. Our findings demonstrate the clinical and functional impact of RNAi machinery alterations in ovarian carcinoma and support the use of siRNA constructs that do not require endogenous Dicer and Drosha for therapeutic applications.
Date: May 6, 2008
Creator: Merritt, William M.; Lin, Yvonne G.; Han, Liz Y.; Kamat, Aparna A.; Spannuth, Whitney A.; Schmandt, Rosemarie et al.
Partner: UNT Libraries Government Documents Department