With multimedia communication growing in popularity, it has become important to develop techniques that will allow a multimedia application to access multimedia files from local as well as remote sites. This thesis describes the methodology used in the design of the Network Multimedia File System (NMFS) protocol. The protocol provides “transparent access to shared files across networks” much like Sun’s Network File System (NFS) protocol. However, NMFS differs from NFS in that it provides a connection-oriented service that allows the user to specify quality of service (QOS) parameters and reserve resources to achieve the desired QOS. NMFS is an application layer protocol and is intended to work with existing multimedia applications, unaltered, on multiple platforms. NMFS will provide real-time delivery of multimedia data over networks both designed and not designed to carry multimedia traffic. A unique feature of this protocol is that it uses an anticipated delivery schedule (ADS) to guide prefetch of portions of files that are likely to be requested in the future. This prefetched data is stored in a local buffer which reduces the need to transfer the data over the variable latency network when the application actually requests it. Thus NMFS provides most unaltered application programs with almost constant latency accesses over a network with variable latency. / Master of Science

The objective of this project was to investigate two mechanisms that are commonly thought to be responsible for heavy metal resistance in aquatic invertebrates. Data were generated based on comparisons of growth and respiration experiments using instar III and IV Chironomus riparius under the influence of 0.0, 62.5, 125, 250, and 500 ppb zinc. Main comparisons were made between larvae that were cultured in clean water conditions and larvae from cultures that had been exposed to 10 ppb zinc for over a year and a half. Instar III larvae from clean water cultures showed significant reductions in growth and respiration rates when exposed to zinc concentrations of 62.5 ppb and greater; growth and respiration rates were significantly reduced in instar IV larvae at 125 and 62.5 ppb, respectively. Instar IV larvae from zinc cultures demonstrated increased tolerance to the metal while instar III larvae displayed no additional tolerance. To determine if the resistance was an acclimation or population adaptation phenomenon, additional growth and respiration experiments were conducted with F2 progeny of adults from zinc cultures that were reared in clean water. Results suggest that both acclimation and adaptation may be responsible for the increased tolerance to the metal. When growth and respiration data were converted to a caloric basis (calories respired per day and calories allocated as growth per day), non-tolerant individuals decreased the amount of energy assimilated per day and increased the proportion of energy respired vs. energy allocated to growth with increasing zinc concentration. Resistant individuals, as a result of changes in toxicological trends, demonstrated less dramatic versions of the previously described trends. / Master of Science

A new experimental method was developed to measure the hysteresis loss during a fatigue test from the load and stroke signals of a standard servo-hydraulic materials testing system. The method was used to characterize changes in properties and performance induced by long-term cyclic loading. Advantages of the load-stroke hysteresis loop include: (1) the fact that contact with the specimen is not required, (2) the fatigue test is not interrupted for data collection, (3) the measured quantity (the hysteresis loop area) is directly related to the (damage) events that alter material properties and life, and (4) a quantitative measure of damage extent and development is obtained. / Master of Science

Three experiments were conducted using crossbred weanling pigs (n=462) to determine the effect of yeast culture (YC) additions to starter diets containing dried whey or a fiber source on performance and nutrient digestibility. An 18% CP corn-soybean meal basal diet was used in all experiments. In Exp. I (n=192), YC (O or .75%) was used in diets with dried whey (0 or 15%) in two 5-wk trials (1 and 2). In Exp. II (n=174), YC (0 or .75%) was used in diets containing no added fiber, 8% soybean hulls (SH), or 8% peanut hulls (PH) in two 5-wk trials (3 and 4). Fifty-four of the pigs in Trial 4 were continued on test for three additional weeks in a grower phase. In Exp. II (n=96), YC (0 or .75%) was used in diets containing three levels of PH (0, 8, and 16%) in one 6-wk trial. In Exp. II, .05% chromic oxide was added to all six diets, and six grab samples were taken (twice daily every other day) during wk 4 and 6 for determination of the digestibility of DM, N, P, and fibrous components using the indirect method. Pigs in all experiments had ad libitum access to feed and water, and body weight and feed consumption were measured weekly. Results from all experiments showed that there was no overall effect of treatments on ADFI. In Exp. I, there was no significant overall effect of YC on ADG or G:F in either trial. In Trial 2 of Exp. I, whey depressed overall ADG (P < .10) and G:F (P < .005). In the nursery phases of Exp. I, there were no significant dietary treatment effects on ADG. Gain to feed ratios tended to be increased (P < .10) by YC additions, but only in diets which also contained fiber. In the grower phase of Trial 4 (Exp. II), fiber additions depressed ADG (P < .005), whereas YC additions improved ADG (P < .01), particularly in pigs fed diets which also contained SH (P < .05). In Exp. III, pigs fed diets containing YC and 8% PH had an overall ADG similar to controls, whereas pigs fed diets containing YC alone or both YC and 16% PH had a lower overall ADG than control pigs (P < .10). Overall G:F ratios were decreased by PH inclusion (P < .01) and by supplemental YC (P < .05). Apparent digestibilities were not influenced by the inclusion of YC. The addition of PH linearly decreased the digestibilities of DM (P < .001), N (P< .05), NDF (P < .001), and ADF (P < .05), and increased the absorption of P (P < .05). These results suggest that YC additions had no effect on ADG or ADFI, variable effects on G:F, and no effect on digestibilities of DM, N, NDF, or ADF, or the apparent absorption of P. Fiber additions, particularly PH at the 16% level, appear to depress ADG and G:F, and the digestibilities of DM, N, NDF, and ADF, but increase apparent absorption of phosphorus. / Master of Science

Solid phase extraction (SPE) has become a popular sample preparation method for the extraction of analytes from complex matrices. Solid phase extraction overcomes such disadvantages as large solvent usage and waste, large amounts of time spent in sample preparation and labor intensive methods with little hope of automation. In this report, SPEC®⋅ Microcolumns are evaluated for the extraction of Zantac® (ranitidine hydrochloride) from urine for high performance liquid chromatography (HPLC) analysis. SPEC®⋅Microcolumns are rigid disc structures with glass fiber impregnated with silica gel. These microcolumns look like packed-bed SPE cartridges but have the advantages of low void volumes and low bed mass that give clean extracts with the use of small amounts of solvents. An SPE method was developed and evaluated for the recovery of Zantac® from water and spiked urine. Percent recoveries and matrix interferences are reported. The limit of detection and analytical range tor the HPLC method of analysis with ultraviolet detection will be presented. / Master of Science

It is known that transform techniques do not represent an optimal way in which to code a signal in terms of theoretical rate distortion bounds. A signal may be coded more efficiently if side information is included with the signal during transmission. This side information can then be used to reconstruct the image at some later time. In this thesis, the type of transform coding used is Multiple Bases Representation (MBR). This coding scheme is known to perform better than transform coding that uses a single basis. The method of Projection Onto Convex Sets (POCS) is used to reconstruct an approximation to the MBR signal using the side information. Thus, any number of constraints may be used as long as they form closed and convex sets and the side information is a priori knowledge required to implement projections onto the defined closed and convex sets. Several closed and convex sets are examined including the MBR, positivity, sign, zero crossing, minimum increase, and minimum decrease constraints. Constraints that tend to limit energy are not as effective as constraints that introduce energy into the signal especially when the observed image is used as the initialization vector. When a different initialization vector is used, the POCS reconstruction performs considerably better. Two initialization vectors are proposed; the observed signal plus white noise and the observed signal plus a constant. The performance of POCS with initialization by the observed signal plus a constant is superior to that when using the observed signal only. One nonconvex constraint is considered. The Laplacian histogram constraint requires other convex constraints to help ensure convergence of the reconstruction algorithm, but produces good quality images. / Master of Science

Fatigue and electrical degradation including low voltage breakdown of ferroelectric lead zirconate titanate Pb(Zr_xTi₁)O₃ (i.e. PZT) thin films are the major limitations for commercial memory applications of these films. It is noted that the presence of oxygen vacancies and their entrapment at the electrode-ferroelectric interfaces are the sources of the degradation phenomena. Attempts were made in this study to solve these problems: 1) by minimizing oxygen vacancy entrapment at the interfaces by employing RuO₂ electrodes; 2) by lowering the oxygen vacancy concentration in PZT films using donor doping (e.g. La³⁺ at Pb²⁺ site and Nb⁵⁺ at Ti/Zr⁴⁺ site). For this study, PZT thin films were prepared by a sol-gel method and deposited on both Pt/Ti/SiO₂/Si and RuO₂/SiO₂/Si substrates. The microstructure and electrical properties, such as hysteresis properties, fatigue, leakage current, time-dependent dielectric breakdown (TDDB), and retention, were studied with regard to the Zr/Ti ratio, the excess lead, the annealing temperature, the electrode material, and the doping amount. Furthermore, the pyrochlore to perovskite phase transformation of PZT on RuO₂ electrodes was also investigated. It was shown that PZT films (Zr/Ti=50/50) with 10 at.% excess lead annealed at 650°C for 30 min possessed the best electrical properties for ferroelectric memory application. In confirmation with earlier theoretical and experimental results, no polarization loss was observed up to 10¹¹ switching cycles for the PZT films deposited on RuO₂ electrodes. However, the low Schottky barrier at the interfaces between RuO₂ and PZT films resulted in a higher leakage current at a high electric fields. Donor doping of PZT films decreased carrier concentrations in PZT films, and thus, decreased the leakage current to acceptable limits. In addition, it was also noted that the pyrochlore to perovskite phase transformation of PZT on RuO₂ was similar to that of PZT on Pt electrodes. It can be concluded that the combination of RuO₂ electrodes and donor doping produced PZT films with high fatigue endurance and low leakage currents which are suitable for memory applications. / Master of Science

The densification behavior of porous gold films made from commercial circuit paste used in microelectronic packaging applications was studied. Constrained gold circuit films of 60-65μm thick were formed by multiple screen printing of the gold paste on rigid alumina substrates, while freestanding films were obtained by carefully peeling off gold films from the substrates after binder burn-out. Optical techniques were developed to determine the densification kinetics of the constrained and freestanding films at temperatures below 1000°C. The densification kinetics of gold films constrained on rigid substrates were observed to be significantly retarded relative to the free films, at all sintering temperatures between 650°C and 900°C studied. SEM studies revealed the microstructure of the constrained films to be much more porous than its freestanding film counterpart. Considerably higher sintering temperatures were required to obtain densities comparable to those of freestanding films. SEM studies also showed no significant difference in grain size between the sintered freestanding and constrained gold films. Inplane tensile stresses generated during constrained-film sintering, was determined to have a maximum value of 460 KPa at the sintering temperature of 750°C. The negligible difference in grain size between the sintered freestanding and constrained gold films, and the small magnitude of the measured tensile stresses, were both determined to be insufficient to account for the observed retardation in the densification kinetics of the constrained gold films. The activation energies for densification of the porous gold films during isothermal sintering, were found to be 21.54±1.03 Kcal/mole and 45.12​​±1.6 Kcal/mole for freestanding and constrained gold films respectively. These values corresponded very well with the activation energies for grain-boundary diffusion and lattice diffusion respectively, for gold as found in literature. Hence from our results of the activation energies for densification of the constrained and freestanding gold films, coupled with our studies on grain growth and stress, we suggest that the observed retardation in the densification kinetics of the constrained gold films are due to a change in the dominant diffusion mechanism during sintering of the porous gold films constrained on rigid substrates. / Master of Science

A total of 1926 A.I. sampled Holstein bulls born from 1984 to 1988 and with first proofs from Summer 1991 to Summer 1993 were used to determine the accuracy of predicting PTAT and DTD from different sources of pedigree information obtained before the bull had daughter information. Pedigree sources used were PA, PI, PTAT_SIRE, and PTAT_DAM. Simple linear regression was used to determine which pedigree source predicted PTAT or DTD with the highest accuracy (highest R²). R² was higher for PA than had the other pedigree sources. R²s for PA to predict initial PTAT and DTD with daughter information were .59 and .18 respectively. Higher weights and R²s for PTAT than DTD resulted from the part whole relationship between PA and PTAT. Accuracy of prediction varied depending on when a bull received his first proof. R² values for PA to predict initial PTAT ranged from .35 to .69, and increased as the time of the pedigree estimate approached the date of the initial proof. R² values for PA to predict initial DTD ranged from .16 to .21 and increased as the time of the pedigree estimate approached the date of the initial proof. The impact of the within herd variance correction which was implemented in the Summer 1993 summary was also evaluated. Correlations between PA, PI, PTAT_SIRE, and PTAT_DAM from the Winter 93 and Summer 93 evaluations were .98, .99, .99, and .96 respectively. Regression of the change in DTD estimated from previous PA minus actual DTD on PTAT_DAM S 93 - PTAT_DAM W 93 for bulls grouped by date of initial proof gave R²s from .00 to .06. It was concluded that the variance correction had little impact on the dam’s of bulls in this study. The impact of the addition of granddaughters (son’s daughters) on the PTA of the bull dam was evaluated. The mean change in PTAT_DAM with the addition of first granddaughters was .016, indicating that the PTAT of the bull dam was slightly underestimated. R²s for the regression of the change in bull dam’s PTAT on DTD, DTD-PA, and PTAT-PA were .39, .54, and .56 respectively. Little evidence was found to indicate a bias based on the testing population used to prove the bull. R²s for the regression of PA and PI on PTAT from the bull’s initial proof with daughter information ranged from .38 to .69, and .26 to .58 respectively. When PA and PI were used to estimate PTAT of a bull’s second proof both within and across NAAB codes, values agreed closely. / Master of Science

A number of studies have concluded that the Myers-Briggs Type Indicator (MBTI) measures four general dimensions of personality; however, their findings also suggest that the MBTI's scales could benefit from improvements in their measurement precision. The degree to which the addition of newly constructed items to the Form F item pool would improve the measurement precision of the four primary MBTI scales was assessed. Using item response theory (IRT) to quantify each scale's performance, findings indicate that the new items substantially increased the test information functions (TIFs) and decreased the standard errors of measurement (SEM), especially in the critical area around the type cutoff scores (e.g., SEMs for scales containing the original plus new items were approximately half the size produced by the original MBTI items). The potential benefits of this increased measurement precision were discussed with respect to a number of applied testing issues. / Master of Science