The additive-plus-multiplicative model, Y_ij = μ + α_i + β_j + ∑_p=1^kλ_pτ_piγ_pj, has been used to describe multiplicative interaction in an unreplicated experiment. Outlier effects often appear as interaction in a two-way analysis of variance with one observation per cell. I use this model in the same setting to study outliers. In data sets with significant interaction, one may be interested in determining whether the cause of the interaction is due to a true interaction, outliers or both. I develop a new technique which can show how outliers can be distinguished from interaction when there are simple outliers in a two-way table. Several examples illustrating the use of this model to describe outliers and interaction are presented. I briefly address the topics of leverage and influence. Leverage measures the impact a change in an observation has on fitted values, whereas influence evaluates the effect deleting an observation has on model estimates. I extend the leverage tables for an additive-plus-multiplicative model of rank 1 to a rank k model. Several examples studying the influence in a two-way nonreplicated table are given. / Ph. D.

Delayed flowering has the potential to overcome the problem of restricted vegetative growth, prior to flowering, that is often associated with double-cropped soybeans [Grycine max (L.) Merr.]. Objectives were to study delayed flowering in soybeans as influenced by date of planting, to estimate the lengths of the component vegetative periods in soybeans under short-day conditions, and to study the mode of inheritance of delayed flowering in soybeans. Date of planting experiments conducted in the field at two Virginia locations using 27 cultivars and breeding lines showed that genotypic differences exist for delayed flowering, especially between delayed and normal flowering isolines. Lengths of the juvenile and inductive periods were estimated for some selected early and late flowering genotypes. F85-84l7 had a longer juvenile period, and F85-1226 had both longer juvenile and inductive periods than their respective early flowering isolines and cultivar Essex. cultivar. The method of moving plants from inductive short-days to long-days, which has been used to estimate the length of inductive period, was adapted to estimate the length of the juvenile period as well. Delayed flowering in soybeans appeared to be controlled by two loci, each with two alleles, and delayed flowering appeared to be recessive. Anyone of the genes in the homozygous recessive state delayed flowering. F85-1226 may be segregating for both genes while F85-84l7 appeared to contain only one. / Ph. D.

We develop a technique for identifying unknown coefficients in parabolic partial differential equations. The identification scheme is based on quasilinearization and is applied to both linear and nonlinear equations where the unknown coefficients may be spatially varying. Our investigation includes derivation, convergence, and numerical testing of the quasilinearization based identification scheme / Ph. D.

Recent task based performance feedback research has concentrated on investigation of the effects of feedback message characteristics to explain variance in individual's post feedback predicted performances. Results of this research have not been well integrated within existing performance feedback models. The present study was conducted to assess the differential effects of feedback message content and feedback message characteristics on real subsequent task performance. Results of the present study indicate that feedback message content, not characteristics, is the critical factor in improving subsequent performance. However, the subject's perception of certain feedback message characteristics is important in influencing subsequent performance via the subject's overall perception/acceptance of the feedback message (Ilgen, et al., 1979). Results also indicate that an additional 5% of the variance in subsequent performance can be explained by incorporating a measure of Locke, et al.'s (1981)goa1 setting into the desire/intention to respond to feedback components of the Ilgen, et a1. feedback model, when subjects are asked to articulate their behavioral plans for future task performance. Results are discussed within the framework of current feedback models and future research needs. / Ph. D.

Microwave processing of polymeric adhesives and composites offers great potential for future materials development. However, basic considerations need to be established which will allow the processing of polymeric systems, both as reactive thermosetting systems and as nonreactive thermoplastics. Fundamental studies relating epoxy network generation to processing conditions have been investigated in a tunable, single-mode microwave cavity at a frequency of 2.45 GHz. These studies demonstrate that in as little as ten minutes fully cured networks with good mechanical properties can be generated. Furthermore, toughened epoxy systems which utilize carefully designed amine-terminated poly (arylene ether sulfone) thermoplastics as reactive oligomers have novel phase-separated morphologies. In fact, it has been demonstrated that the morphology in these multiphase systems may actually be controlled by utilizing microwave processing. In addition to epoxy resins, the microwave processing of functionalized poly(arylene ether ketone)s (PEK) has also been demonstrated. PEK's are typically classified as high performance thermoplastics; however, with the appropriate terminal functionalities these ductile thermoplastics may also be transformed into tough, solvent resistant networks. In the current investigation amine-, maleimide- and nadimide-terminated PEK's of controlled molecular weights were synthesized and crosslinked by both electromagnetic radiation (EMR) processing and classical thermal treatments. EMR processing resulted in network formation at rates as high as 20 times faster than conventional thermal treatments at the same isothermal cure temperature. Relationships among processing conditions, curing rates and endgroup functionality were investigated. Novel poly (arylene ether ketone)/poly(aryl imide) homo- and poly (dimethylsiloxane) segmented copolymer blend systems have been investigated to determine the influence of chemical structure on miscibility and physical property behavior. Melt processing results demonstrate that the glass transition temperature of PEEK™ blends increase monotonically with polyimide content. Indeed, T_g'S as high as 240°C have been achieved for certain blend compositions, while still retaining adequate crystallization to provide solvent resistance. The experimental T_g results are in good agreement with the theoretical values predicted by the Fox equation. Lastly, electromagnetic processing was applied to PEEK™/Ultem™ blends to demonstrate the principles of "microwave calorimetry". / Ph. D.

This study (1) determines the information managers commonly need to make decisions and initiate actions to improve performance, based on selected case studies, (2) investigates and explains the features and issues involved with how the different versions of TFPM address these information needs, and (3) develops a teaching model of TFPM. Based on the literature review, interviews with experts, and experiences with applications, the features and differences of the available TFPM versions were explained, providing sample applications whenever necessary. Using four selected cases, common user information needs were identified and compared with results of previous surveys. Alternative TFPM applications for each case were developed and evaluated using Archer's (1978) Design Process as implemented with VPC's (1990) PRFORM software. Based on the evaluations of the TFPM applications in each of the case studies, a teaching TFPM model was developed incorporating the features of the available TFPM versions that most appropriately responded to the common information needs. Some other features not portrayed in the available TFPM versions were added to facilitate portrayal, understanding, and acceptance for new users. There are basically two models of TFPM - the Productivity Indices (PI) Model and the Profitability = Productivity + Price Recovery (PPPR) Model. I proved that as implemented with discrete variables, Gollop's Model is equivalent to the PPPR Model. Various versions of these two models feature differences in deflation, aggregation of Outputs, inputs, and/or organizational units, treatment of capital, computation of dollar effects of changes in performance, and how to use TFPM for planning. The common information needs identified were (1) measures of a firm's past performance using physical productivity related to profitability; (2) measures of individual organizational units’ productivity aggregated into plant, division, or firm level productivity; (3) partial measures to explain what factors dr.ve the total performance measures; and (4) evaluations of plans/budgets to ensure performance improvement. Based on the evaluations of possible TFPM versions appropriate for each application, REALST stands out as the most advanced and flexible version. However, it has become too complicated for first-time users. Hence, the teaching TFPM model I have developed is a simplified version of REALST. / Ph. D.

In this thesis we answer a number of unsolved problems in generalized paracompact topological spaces. Examples satisfying the T₄ separation axiom are constructed showing the relationship between the properties B(D, ω₀)-refinability, B(D, λ)-refinability, and weak θ̅-refinability. The properties B(D, λ)-refinability and weak θ̅-refinability are shown to be strictly weaker than B(D, ω₀)-refinability. Sum theorems, mapping theorems, and o—product theorems are obtained for B(D, ω₀)-refinability, weak θ̅-refinability, and several other properties. The σ—product theorem for B(D,ω₀)-refinability, weak θ̅-refinability, and other properties are shown to follow from a new special B(D,ω₀) sum theorem. / Ph. D.

Interpolation conditions on rational matrix functions expressed in terms of residues are studied. As a compact way of expressing tangential interpolation conditions of arbitrarily high multiplicity possibly from both sides simultaneously, interpolation conditions are represented in terms of residues. The minimal possible complexity, measured by the McMillan degree, of interpolants is found in terms of the controllability and the observability indices of certain pairs of matrices which are part of given data. An interpolant of such complexity is obtained in realization form. This leads to another approach to the partial realization problem. As a generalization of the well-known Lagrange interpolation problem for scalar polynomials, the problem of seeking for a matrix polynomial interpolant of low complexity is studied. The main tool is state space methods borrowed from systems theory. After adoption of state space methods, problems concerning rational matrix functions are reduced to the realm of linear algebra. / Ph. D.

One of the major problems in computer vision involves dealing with uncertain information. Occlusion, dissimilar views, insufficient illumination, insufficient resolution, and degradation give rise to imprecise data. At the same time, incomplete or local knowledge of the scene gives rise to imprecise interpretation rules. Uncertainty arises at different processing levels of computer vision either because of the imprecise data or because of the imprecise interpretation rules. It is natural to build computer vision systems that incorporate uncertainty reasoning. The Dempster-Shafer (D-S) theory of evidence is appealing for coping with uncertainty hierarchically. However, very little work has been done to apply D-S theory to practical vision systems because some important problems are yet to be resolved. / Ph. D.

This dissertation presents different methods for the deconvolution of time domain signals. The techniques developed in this work are frequency domain filtering techniques. and are suitable for the type of deconvolution problems encountered in time domain reflectometry (TOR). They include a smoothing technique that is a variant of the well known lowpass filter. This technique is parameter dependent in order to allow for adequate choice of cutoff frequency. Another more powerful method developed is an adaptive smoothing (regularization) technique, which is both frequency dependent and input-signal dependent as well. Thus, it is an adaptive technique whose performance depends on a parameter associated with its smoothing constraint. These frequency domain techniques and their variants are parameter dependent; hence a parameter optimization criterion must be included. However, in deriving an optimization criterion, great importance must be given to its adequacy in the determination of the appropriate parameter value as well its time efficiency. A parameter optimization method that fulfills those two reqUirements is also developed. The method is fully implemented in the frequency domain in which the filtering techniques are used. The techniques developed are derived with a magnitude component only. i.e., non-causal. The limited derivation is due to the fact that we are usually interested in reducing only the noise level from the magnitude point of view. However, If we consider time domain measurements as an example, physical pulses and transients are causal functions of time, i.e., their values are zero before t = 0, the time at which they begin. Their measured waveform data are also causal. When deconvolution processing is applied to remove instrumentation errors and/or suppress the effects of noise, non-causal deconvolution methods, that were mentioned previously, may introduce unacceptable errors. The conventional deconvolution is modified to ensure that causality is maintained in the deconvolution result. The impulse response of an unknown system is recovered from time domain reflectometry data by implementing a method based on the homomorphic deconvolution technique. In time domain reflectometry, the reflected waveform by a line with several discontinuities is represented as the convolution of the reflection coefficient of the line and the input excitation of the line source. The reflection coefficient is generally a train of spikes (delta functions) when the discontinuities are resistive. However, this is not the case when the discontinuities are capacitive in nature. In this work, we will attempt to show that the conventional frequency domain deconvolution techniques fail to provide good estimates when the waveform contains certain amounts of noise. Since it has been shown that homomorphic systems are useful in separating signals which have combined through convolution, homomorphic filtering can then be applied to recover either the input excitation or the impulse response (reflection coeffiCient) of the network. / Ph. D.