Physical Sciences and Mathematics Commons^™

Time-Based Clustering And Its Relationship With Mutual Information Theory, Charles R. Tolle

Utah Space Grant Consortium

This paper re-introduces the concepts of TimeBased Clustering (TBC). Also, the ideas of oversampling and embedding time are introduced in connection with mutual information theory. These concepts are then extended through the use of the Time-Based Clustering (TBC) problem. Mutual information curves for the Rössler system are shown to match a slice through the rich cost function space spanned by the Time-Based Clustering (TBC) solution. In closing, some possible repercussions of this find are discussed.

Examination Of The Combustion Morphology Of Ziconium Carbide Using Scanning Electron Microscopy, Brian R. Newbold

Utah Space Grant Consortium

Calculation of viscous particle damping of acoustic combustion instability in solid propellant motors requires an understanding of the combustion behavior of added particles and oxides. A simple hydrogen/oxygen flame was used to ignite carefully sieved zirconium carbide particles which were impacted on slides at different levels below the burner.

Scanning electron microscopy revealed that zirconium carbide has a complex heterogeneous combustion morphology. Initially, particles are partly vitreous and crystalline with a complex surface area. Upon ignition, particles round, but soon wrinkle as zirconium oxide deposits on the surface. Such morphology information is useful to refine viscous damping calculations.

Gps Tracking For Small Sounding Rockets, Darin K. Fowers

Utah Space Grant Consortium

Active areas of research often create the need for improved technology to make observations in a way that has not previously been utilized. Such is the case with middle atmospheric research. This 60 to 120 km region of the atmosphere is too low to be directly probed by satellites and too high to be probed by research airplanes or high altitude balloons. Sounding rockets are the only vehicle that can carry instruments for in situ measurements. Up until now only a few methods have been available to track the location of a sounding rocket - radar skin tracking, radio beacon …

Absolute Solar Transmittance Interferometer, Arthur W. Dybdahl

Utah Space Grant Consortium

The University of Denver's Absolute Solar Transmittance Interferometer (ASTI) has been developed to make high-resolution infrared (TR) radiometric measurements of the incident solar radiance and irradiance at the Earth's surface. It is a research instrument that provides spectral data of high scientific interest in the short-wave infrared (SWIR) band covering 0.97 to 5.13 µm. This band contains about 20 percent of the suns incident energy, having a significant impact on global as well as regional climate. ASTI spectra are used to provide significant radiometric information describing the SWlR transmittance and absorption properties of the atmosphere. The ASTl research program and …

Flow Past Bluff Bodies, Thad S. Morton

Utah Space Grant Consortium

More than a century ago Kirchhoff solved for the velocity distribution within an elliptical patch of uniform vorticity. That solution became the basis for all further studies of elliptical vortices and has been regarded as the only known exact solution for a steady, elliptical patch of uniform vorticity. In the present paper, an exact solution for a new elliptical patch of uniform vorticity is presented. The vortex is constructed of streamlines of constant eccentricity. By specifying a velocity distribution along either of the principle axes of the vortex, continuity between differentially-spaced streamlines provides the velocity distribution throughout the vortex. Some …

Internet Access For Instrumental Control And Data Viewing At Bear Lake Observatory, Kerry M. Nelson

Utah Space Grant Consortium

Two departments at Utah State University have collaborated to operate an observatory near Bear Lake, Utah. The purpose of the observatory is to study various phenomena in the upper atmosphere, and houses such instruments as high-power CCD cameras, a radar system, and others. Until recently, only one instrument has had the capability of being controlled and monitored remotely. Since the other instruments do not have this capability, they must be set up and left running, only to have a person drive up to the observatory to check their operation after a given amount of time. This monitoring system is not …

Microgravity Effects On Water Flow And Distribution In Unsaturated Porous Media, Scott B. Jones, Dani Or

Utah Space Grant Consortium

Several aspects of the physical processes of liquid flow and distribution within partially saturated porous media are altered in the reduced gravity conditions (microgravity) of orbiting spacecraft. The objectives of this study were to simulate and test measured flow and distribution in porous media from a microgravity environment using conventional capillary flow theory. Two past microgravity experiments studying water supply and uptake in porous media took place on a U.S. space shuttle, titled ASC-1, and on the Russian space station Mir, titled Greenhouse-2. Data from microgravity and ground experiments were simulated using similar physical flow models by elimination of the …

Validation Study Of A Novel Neonatal Pneumotach, Scott A. Kofoed

Utah Space Grant Consortium

We have developed a pneumotach for measuring respiratory gas flows in humans and or animals. The pneumotach enables the monitoring of respiratory and metabolic function in human subjects over extended periods of time. A bench study was conducted to validate the new pneumotach system against other predicate devices. The pneumotach under test compared well to the predicate devices used.

Binary Classification Of Wind Fields Through Hypothesis Testing On Scatterometer Measurements, Paul E. Johnson

Utah Space Grant Consortium

Scatterometers are radars specially designed to nearsurface wind over the ocean from space. Traditional scatterometer wind estimation inverts the model function relationship between the wind and backscatter at each resolution element, yielding a set of ambiguities due to the many-to-one mapping of the model function. Field-wise wind estimation dramatically reduces the number of ambiguities by estimating the wind at many resolution elements, simultaneously, using a wind model that constrains the spatial variability of the wind. However, the appropriate choice of the model order needed for a particular wind field is not known a priori. The approximate model order is valuable …

Temporal Change Enhancement In Multispectral Images Remotely Sensed From Satellites, William P. Pfaff

Utah Space Grant Consortium

The application of principal components analysis to multispectral satellite images is a routine way to present the data in false-color composite images. These composite images include a very high percentage of available information and have no correlation between the displayed colors. The transformation of multispectral image data into its principal components is also an effective way to separate image information from noise. This paper describes a procedure for temporal change enhancement which exploits both the decorrelation and noise isolation properties of the principal components transformation. Using simulated temporal change, this procedure was demonstrated to be more effective than the standard …

Development Of A Full-Spectrum Raman Device For Detection Of Environmental Contaminants, David G. Smith

Utah Space Grant Consortium

NASA needs sensors to accurately monitor the water and atmospheric quality in its space habitat. Concerns for health and safety necessitate the development of sensors to measure common atmospheric gas concentrations, as well as trace contaminants (low ppm or ppb), including both combustible and noncombustible gases. The University of Utah is developing an enhanced Raman monitoring system to detect airborne, environmental contaminants. We have collected laboratory data to benchmark current laser Raman technology for gas analysis, which provides a reference for future developments. The objective of this project was to design a prototype gas-phase monitor, incorporating new technology that would …

Using Ranks To Perform Exact And Estimated Exact Tests In Designed Experiments, Scott J. Richter, Mark E. Payton

Conference on Applied Statistics in Agriculture

A procedure is studied that uses rank transformed data to perform exact and estimated exact tests which is an alternative to the commonly used F-ratio test procedure. First, a common parametric test statistic is computed using rank transformed data, where two methods of ranking - ranks taken of the original observations, and ranks taken after aligning the observations - are studied. Significance is then determined using either the exact permutation distribution of the statistic or an estimate of this distribution based on a random sample of all possible permutations. Simulation studies compare the performance of this method to both the …

Testing Variance Components Using The Glm And Mixed Procedures Of Sas®, Ron Mcnew, Andy Mauromoustakos

Conference on Applied Statistics in Agriculture

The test of a variance component in random and mixed normal linear models can be done using the F statistic from the analysis of variance or the Wald statistic which is the ratio of the variance component estimate to its estimated standard error. These are the methods used in the GLM and MIXED procedures of SAS®. We show that these two tests can give different results on the same data. For the one-way random model, the one-sided Wald test on the among group variance component can never be significant at the 0.05 probability level when the number of levels of …

The Statistical Analysis Of Active Control Equivalence Studies, Armando Garsd, Susana F. Delfino

Conference on Applied Statistics in Agriculture

In experimental work, the notion of equivalence falls short of the idea of equality. Thus, the effects of two treatments, while not identical, may still be regarded as equivalent if their difference is negligible in a certain sense. This simple distinction raises not only technical difficulties, since of necessity it results in special statistical procedures, but also deeper conceptual issues, since one has to ask why two treatments should be equivalent but not equal, more specifically, whether their being merely equivalent has any bearing on the practical questions posed by the data. In this paper we present examples, drawn from …

The Analysis Of The Two-Period Repeated Measurements Crossover Design With Application To A Forestry Problem, Armando Garsd, Maria C. Fabrizio, Maria V. López

Conference on Applied Statistics in Agriculture

The two-period repeated measurements crossover design is not often used in agricultural studies. It is, however, an attractive model, involving the confluence of two powerful statistical ideas, treatment crossover and repeated measurements on the same experimental unit. This paper presents one approach for the statistical analysis of such design based on the work of Wallenstein and Fisher (1977). It is shown how the data may be transformed so that it can be analyzed under the framework of a completely randomized repeated measurements design. We formalize the analysis in the context of a forestry experiment conducted on poplar trees (Populus SP.), …

The Use Of Inverse Theory On An Ill-Posed Environmental Composite Sampling Problem, V. A. Lancaster, S. Keller-Mcnulty

Conference on Applied Statistics in Agriculture

As an alternative to retesting, the use of inverse theory techniques is proposed to resolve the lack of information inherent in composite sampling methods. This paper evaluates the feasibility of combining composite sampling with the inverse theory technique of linear regularization on an environmental site characterization investigation. Federal legislation has mandated the cleanup of hazardous waste sites, creating the need to characterize these sites for various chemical constituents. An abundance of samples, high measurement costs, and limited budgets create the appeal of compositing samples. We propose that the number of costly laboratory analyses can be reduced by combining composite sampling …

Bootstrap Confidence Intervals From Adaptive Sampling Of An Insect Population, Jeffrey S. Pontius, Mary C. Christman

Conference on Applied Statistics in Agriculture

We construct 90% normal, percentile, and bias-corrected and accelerated confidence intervals using a finite population bootstrapping algorithm based on adaptive sampling in an agroecosystem. We evaluate the interval estimates based on sampling simulations of a spatially arranged population of plots that contain counts of beet webworms and based on an adaptive condition that generates small networks. The sampling distributions of the original sample estimates and of the bootstrap estimates were generally similar and symmetric. The simulation coverages were from 84% to 90% and similar under any of the sample sizes and any of the three confidence interval types. This study …

Some Experiences With Neural Networks, Lynda L. Ballou, Dallas E. Johnson

Conference on Applied Statistics in Agriculture

This paper gives a brief overview of artificial neural networks which may be used to model data similar to the kind where one usually considers regression models. Many practitioners believe that neural networks perform better than regression models for prediction purposes. Some simulations were performed using three different neural net programs, namely Braincel, Ripley's S+ program, and Nychka's S+ program. These simulations reveal some interesting aspects of neural net programs which should be of interest to anyone considering the use of neural net programs to model continuous data.

Some Factors Limiting The Use Of Generalized Linear Models In Agricultural Research, Walter W. Stroup

Conference on Applied Statistics in Agriculture

The generalized linear model (GLM) is a "hot" topic in statistics. Numerous research articles on GLM's appear in each edition of all major journals in statistics. GLM's are the subject of substantial numbers of presentations at most statistics conferences. Despite the high level of interest and research activity within the statistics community, GLM's are not widely used, with some exceptions, by biological scientists in the statistical analysis of their research data. Why? Reasons include 1) many statisticians are not comfortable with GLM's, 2) the biological research community is not familiar with GLM's, and 3) there is little in introductory statistics …

How Good Are Spatial Glm's? A Simulation Study, Roger G. Collins, Walter W. Stroup, Stephen D. Kachman

Conference on Applied Statistics in Agriculture

An area of increasing interest to agricultural and ecological researchers is the analysis of spatially correlated non-normal data. A generalized linear model(GLM) accounting for spatial covariance was presented by Gotway and Stroup (1997). Their method included approximate inference based on asymptotic distributions. A simulation study was conducted to assess the small sample behavior of their proposed estimates and test statistics. This study suggests that the spatial GLM yields unbiased estimates of treatment means and differences for binomial data, that the spatial GLM improves precision, as measured by MSE, and that the approximate F-statistic is acceptable for hypothesis testing.

Alternative Analyses Of Crossover Designs With More Than Two Periods, Carla L. Goad, Dallas E. Johnson

Conference on Applied Statistics in Agriculture

A crossover experiment is a special form of a repeated measures experiment. An appropriate analysis of a repeated measures experiment depends on the form of the varian-cecovariance matrix of the repeated measures. Certain forms of this matrix yield valid analysis of variance F -tests while other forms invalidate these tests. In a crossover experiment where analysis of variance tests are invalid, two alternative tests of a linear contrast of the parameters are proposed. In addition to these approximate t-tests, three alternative methods for testing for equal treatment effects and equal carryover effects are proposed. A simulation study is conducted to …

Bioavailability And Cv Component Comparison In A Crossover, Zhiming Wang, Vince A. Uthoff

Conference on Applied Statistics in Agriculture

Two medication formulations are compared using noncompartmental pharmacokinetic (PK) variables. However, more than the ratio of mean effects is of interest. A difference in formulation coeficients of varication (CV), within- or between-subject, is sought. The experimental design chosen is a 2 sequence crossover design of the form ABBA and BAAB, where A and B are two medication formulations. A mixed linear model is defined that contains random effects for subjects and for subject by formulation interactions. The model has fixed effects for the average formulation effects and period effects. The 2 formulations are assumed to have different error terms. The …

Equivalence Testing In Agriculture Experiments, Brian J. Fergen

Conference on Applied Statistics in Agriculture

Equivalence testing is a relatively new area of research in statistics. It's development has been motivated in large part by the need for statistical methods for determining if generic drugs are bioequivalent to their name brand counterparts. The application of equivalence testing methods to data resulting from experiments and surveys unrelated to drug development, and in particular agriculture-related experiments, is infrequent and possibly non-existent. These methods provide useful alternatives to the analysis methods currently being used. In this paper, an overview of the philosophy of equivalence testing and a review of equivalence testing methods are presented. Additionally, experimental situations for …

Covariance Adjustment In Studies Involving Observational Factors Or Covariates Influenced By Treatments, O. B. Allen, I. B. Mandell, J. W. Wilton, L. B. Buchanan-Smith

Conference on Applied Statistics in Agriculture

We extend the definition of adjusted treatment means in the analysis of covariance to deal with the case where some of the covariates are influenced by treatments or where some of the factors are observational. In these cases, comparison of treatment means adjusted to a common value of the covariate may be inappropriate. Partially adjusted means are defined and it is shown that special cases include the usual adjusted means (adjusted to a common value for each of the covariates) and unadjusted means. In fact, in a multifactorial experiment, one can, by appropriate choice of adjustment, compare adjusted means for …

Comparing The Use Of Block And Covariate Information In Analysis Of Variance, James R. Schwenke

Conference on Applied Statistics in Agriculture

Of primary concern in the statistical analysis of the results of an experiment is to quantify the mean response to treatment and to accurately quantify the experimentation error variance. The traditional approach to account for nuisance sources of variation or a heterogeneous population is to group or block the population (or sample) into homogeneous groups with respect to a concomitant variable. A blocking term then is included in the statistical analysis. Alternatively, concomitant variables can be used as covariate information in a statistical analysis. A statistical analysis incorporating blocks assumes that the magnitude of difference in treatment response is equal …

Analysis Of A Midwest Farmer Survey Of Pest Infestation, Susanne Aref

Conference on Applied Statistics in Agriculture

A survey of farmers rating the severity of crop pest infestation in their fields was conducted in the Midwest in 1992. The purpose of the present study was to detennine summary variables of the pest infestation ratings and the effect of region, soil type, and tillage on these summary variables. The pests were in the following six categories: perennial and annual weeds, insects and diseases of com (Zea mays L.) and insects and diseases of soybean (Glycine max (L.) MerritT). Categorical models were used to analyze individual pest ratings. A non-parametric method, the Sheirer-Ray-Hare extension of the Kruskal-Wallis test …

Empirical Estimates Of Power For Binomial Data With Mixed Models, R. K. Splan, L. D. Van Vleck, H. D. Hafs

Conference on Applied Statistics in Agriculture

Observations on return to estrus from anestrus postpartum beef cows were used as the basis for a simulation study to develop a method to determine numbers of locations and animals per treatment per location to achieve a specified power of test. Estimates of among location and total variance were obtained by REML from the data set and then used to generate simulated data for the binomial trait. Each combination of several pre-determined factors was replicated 1000 times. Pre-determined factors were number of locations, number of animals per treatment per location, desired detectable difference due to treatment, alpha-probability level and ratio …

Alternative Procedures For Estimation Of Nonlinear Regression Parameters, William J. Price, Bahman Shafii

Conference on Applied Statistics in Agriculture

Biological research data are often represented using nonlinear model specifications that lend themselves to the testing of relevant hypotheses concerning the model parameters. This is typically achieved with classical nonlinear least squares techniques such as Gauss-Newton or Levenberg-Marquardt which allow for both the estimation and inference phases of the analysis. Under some circumstances, however, sensitivity to data or model specifications may lead these methods to fail convergence tests or exhibit nonlinearity in the parameter estimates, which will in turn limit the usefulness of inferential results. In such cases, other estimation methods may present a means of avoiding these problems while …

Confidence Intervals For Heritability In A Mixed Linear Model, Brent D. Burch, Hari K. Iyer

Conference on Applied Statistics in Agriculture

A family of procedures is given to construct confidence intervals for the heritability of a trait in a mixed linear model. The procedures are applicable for constructing confidence intervals for a ratio of variance components in a mixed linear model having two sources of variation. The resulting intervals are evaluated in terms of expected length. The investigator may select the best confidence interval procedure from the family of procedures based on the interval( s) having short expected length. Confidence intervals for loineye data using bulls from a Red Angus seed stock herd will be presented.

Using Prior Knowledge Of The Intraclass Correlation To Increase The Power Of Tests For Treatment Means, Marjorie E. Bond, James J. Higgins

Conference on Applied Statistics in Agriculture

It is common in agricultural research to have experimental units that consist of multiple observational units. For instance, treatments may be applied to pens of animals, pens being the experimental units, while weights are measured on individual animals, the observational units. If there are a small number of experimental units, the power of statistical tests for treatment effects can be small regardless of the number of observational units. We show that it is possible to increase the power of such statistical tests by taking advantage of prior knowledge of the intraclass correlation. Our assertion is that such prior knowledge is …