This dissertation analyzes hospital efficiency using various econometric techniques. The first essay provides additional and recent evidence to the presence of contract management behavior in the U.S. hospital industry. Unlike previous studies, which focus on either an input-demand equation or the cost function of the firm, this paper estimates the two jointly using a system of nonlinear equations. Moreover, it addresses the longitudinal problem of institutions adopting contract management in different years, by creating a matched control group of non-adopters with the same longitudinal distribution as the group under study. The estimation procedure then finds that labor, and not capital, is the preferred input in U.S. hospitals regardless of managerial contract status. With institutions that adopt contract management benefiting from lower labor inefficiencies than the simulated non-contract adopters. These results suggest that while there is a propensity for expense preference behavior towards the labor input, contract managed firms are able to introduce efficiencies over conventional, owner controlled, firms. Using data for the years 1998 through 2007, the second essay investigates the production technology and cost efficiency faced by Florida hospitals. A stochastic frontier multiproduct cost function is estimated in order to test for economies of scale, economies of scope, and relative cost efficiencies. The results suggest that small-sized hospitals experience economies of scale, while large and medium sized institutions do not. The empirical findings show that Florida hospitals enjoy significant scope economies, regardless of size. Lastly, the evidence suggests that there is a link between hospital size and relative cost efficiency. The results of the study imply that state policy makers should be focused on increasing hospital scale for smaller institutions while facilitating the expansion of multiproduct production for larger hospitals. The third and final essay employs a two staged approach in analyzing the efficiency of hospitals in the state of Florida. In the first stage, the Banker, Charnes, and Cooper model of Data Envelopment Analysis is employed in order to derive overall technical efficiency scores for each non-specialty hospital in the state. Additionally, input slacks are calculated and reported in order to identify the factors of production that each hospital may be over utilizing. In the second stage, we employ a Tobit regression model in order to analyze the effects a number of structural, managerial, and environmental factors may have on a hospital's efficiency. The results indicated that most non-specialty hospitals in the state are operating away from the efficient production frontier. The results also indicate that the structural make up, managerial choices, and level of competition Florida hospitals face have an impact on their overall technical efficiency.

Energy efficient infrastructures or green IT (Information Technology) has recently become a hot button issue for most corporations as they strive to eliminate every inefficiency from their enterprise IT systems and save capital and operational costs. Vendors of IT equipment now compete on the power efficiency of their devices, and as a result, many of the new equipment models are indeed more energy efficient. Various studies have estimated the annual electricity consumed by networking devices in the U.S. in the range of 6 - 20 Terra Watt hours. Our research has the potential to make promising solutions solve those overuses of electricity. An energy-efficient data center network architecture which can lower the energy consumption is highly desirable. First of all, we propose a fair bandwidth allocation algorithm which adopts the max-min fairness principle to decrease power consumption on packet switch fabric interconnects. Specifically, we include power aware computing factor as high power dissipation in switches which is fast turning into a key problem, owing to increasing line speeds and decreasing chip sizes. This efficient algorithm could not only reduce the convergence iterations but also lower processing power utilization on switch fabric interconnects. Secondly, we study the deployment strategy of multicast switches in hybrid mode in energy-aware data center network: a case of famous Fat-tree topology. The objective is to find the best location to deploy multicast switch not only to achieve optimal bandwidth utilization but also minimize power consumption. We show that it is possible to easily achieve nearly 50% of energy consumption after applying our proposed algorithm. Finally, although there exists a number of energy optimization solutions for DCNs, they consider only either the hosts or network, but not both. We propose a joint optimization scheme that simultaneously optimizes virtual machine (VM) placement and network flow routing to maximize energy savings. The simulation results fully demonstrate that our design outperforms existing host- or network-only optimization solutions, and well approximates the ideal but NP-complete linear program. To sum up, this study could be crucial for guiding future eco-friendly data center network that deploy our algorithm on four major layers (with reference to OSI seven layers) which are physical, data link, network and application layer to benefit power consumption in green data center.

Adaptive modulation has been actively researched as a means to increase spectral efficiency of wireless communications systems. In general, analytic closed form models have been derived for the performance of the communications system as a function of the control parameters. However, in systems where general error correction coding is employed, it may be difficult to derive closed form performance functions of the communications systems. In addition, in closed form optimization, real time adaptation is not possible. Systems designed with deterministic state optimization are developed offline for a certain set of parameters and hardwired into mobile devices. In this thesis we present stochastic learning algorithms for adaptive modulation design. The algorithms presented allow for adaptive modulation system design in-dependent of error correction coding and modulation constellation requirements. In real time, the performance of the system is measured and stochastic approximation techniques are used to learn the optimal transmission parameters of the system. The technique is applied to Software Defined Radio (SDR) platforms, an emerging wireless technology which is currently being researched as a means of designing intelligent communications devices. The fundamental property that sets SDR apart from traditional radios is that the communications parameters are controlled in software, allowing for real-time control of physical layer communications. Our treatment begins by modeling the time evolution of the adaptive modulation process as a general state space Markov chain. We show the existence and uniqueness of the invariant measure and model performance functions as expectations with respect to the invariant measure. We consider constrained and unconstrained throughput optimization. We show that the cost functions considered are convex. Next we present stochastic approximation algorithms that are used to estimate the gradient of the cost function given only noisy estimates. We conclude by presenting simulation results obtained by the presented method. The learning based method is able to achieve the maximum throughput as dictated by exhaustive Monte Carlo simulation of the communications system, which provide an upper bound on performance. In addition, the learning algorithm is able to optimize communications under various error correction schemes. The tracking abilities of the algorithm are also demonstrated. We see that the proposed method is able to track optimal throughput settings as constraints are changed in time. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

With increasing energy costs and competitive pressures, interest has increased in surveying installed pumps for potential energy savings. Field pump efficiency tests are required to assess pumping performance and help to identify improvement opportunities. This work concerns the on-site measurements of pulp-suspension pumping efficiency. This involves the measurement of pump head, flow rate and power consumption. Provided that consistent flow measurements are available, it is possible to reliably and non-invasively measure actual pump system efficiencies in pulp suspension flow, with a minimum process disturbance. As part of a most appropriate measurement-procedure study, four portable nonintrusive flow meters were evaluated on site for pulp suspension flow. The Fast Fourier Transform Doppler was found to be the most suitable for a pulp mill pump survey. Efficiency measurements were performed on six pump systems with motors between 100 and 700 HP. It is shown that as-installed pump efficiency can be used to help predict the degradation of the pump and also its effect on the pumping system’s operation. A system approach analysis was performed in each case, which can be effective in assessing system performance and finding potential enhancements. The use of variable speed drives allows the operating point to move along the system curve, requiring less energy to drive the pump. VSD of larger motors are expensive and their profitability compared to other modification alternatives should always be carefully checked by calculations based on accurate on site measurements and life cycle costs. Finally, in this survey of six pump systems, significant potential savings of around 30% of present power consumption were found. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

The objective of the study was to determine the feed conversion efficiency (FCE), carcass characteristics, physico-chemical quality, fatty acid (FA) composition and shelf life of pork from pigs fed diets containing either 0% (T1), 2.5% (T2), 5% (T3) or 7.5% (T4) Moringa oleifera leaf meal (MOLM). Consumer health-related perceptions on pork and fatty acids were also investigated. Twenty four crossbred Large White x Landrace pigs of both sexes at 18 weeks of age and initially weighing 71.6 kg on average were housed individually and had ad libitum access to one of the four dietary treatments for a period of six weeks. Average daily feed intake (ADFI) and average daily gain (ADG) and feed conversion ratios (FCR) were calculated as an indication of FCE and pigs were slaughtered at an average live weight of 99.6 kg. Carcass traits such as back fat thickness (BFT), carcass temperatures and pH readings taken 45 minutes and 24 hours (pH45 and pHu) post mortem were recorded. M. longissimus thoracis et lumborum (LTL) samples were taken from each carcass for the determination of lightness (L*), redness (a*), yellowness (b*), thawing loss percentage (TL%), cooking loss percentage (CL%), Warner Bratzler Shear Force (WBSF), shelf life and FA composition. Furthermore a survey was conducted amongst 80 University of Fort Hare Students to determine their health-related perceptions on pork and fatty acids as well as their pork consumption frequency using questionnaires. The FCE of pigs fed on 0-5% MOLM (T1, T2 and T3) diets did not differ significantly, but the FCE of pigs fed 7.5% MOLM (T4) was significantly (p<0.05) reduced. No significant relationship was reported between inclusion of MOLM carcass characteristics and physico-chemical pork quality. There was however a significant improvement (p<0.05) in the shelf life of the pork from MOLM fed pigs in terms of colour and odour during 10 days of refrigerated storage (at 3±1°C). There was a significant (p<0.05) reduction in the total intramuscular fat (IMF) content and the saturated fatty acid (SFA) C18:0 (stearic acid) content and an overall non-significant (p>0.05) increase in the poly unsaturated fatty acid (PUFA) content of pork from MOLM fed pigs. The possible reason for this is that the feeding of MOLM was commenced when the pigs were at an advanced age and weight. The survey revealed that the majority of interviewed students consume fresh (39.7%) and processed (32.4%) pork two to three times a week, perceive pork to be generally healthy (70%) and the second most healthy meat type (39.5%). While the majority (55.4%) were aware of the health implications of FAs they did not know which FA classes pose more of a health risk (51.3%). In conclusion2.5% and 5% of MOLM in finisher pig feed did not negatively affect FCE, carcass characteristics or physico-chemical meat quality; significantly improved pork shelf life and reduced total IMF and SFA content of pork but 7.5% MOLM negatively affected FCE; and the majority of students perceive pork to be the second most healthy type of meat and are generally aware of the health implications of FAs.

Knowledge of water use, through water foot printing (WF) in smallholder agriculture crop production is the key to the global fight against poverty, achievement of food security and sustainability within the world’s rural community. Water footprint of a crop can be defined as the volume of fresh water used to produce a certain crop in all the steps in the production line. This study, therefore aimed at contributing towards improvements in rural livelihoods by raising awareness of the increased productive use of green, blue and grey water in smallholder agriculture in South Africa. This was done through determination of water footprints of five vegetable crops, i.e. potatoes (Solanum tuberosum), tomatoes (Solanum lycopersicum), dry beans (Phaseolus vulgaris), cabbage (Brassica oleracea spp) and spinach (Spinacia oleracea) in the 2000-2013 period. Quantification of water footprints has been done worldwide but, in South Africa (SA) focus has mostly been on the industrial and domestic sector. Water footprint assessment framework, was used to estimate the full impact of vegetable production on water resources at Zanyokwe, Thabina and Tugela Ferry irrigation schemes as case studies. The CROPWAT@ model was used to calculate crop evapotranspiration, differentiating green and blue water. Local climatic data were obtained from SA weather services, while the crop and soil parameters were obtained from the FAO data base. Nitrogen was considered the main pollutant hence its use in the grey water footprint calculation. Generally, Thabina irrigation scheme had the highest water footprint, followed by Tugela Ferry irrigation scheme whilst Zanyokwe irrigation scheme had the lowest. Green beans had the highest water footprint at all the three irrigation schemes with Thabina irrigation scheme having the highest (3535.1 m3/ton). For Tugela Ferry irrigation scheme, the calculated WF was 2753 m3/ton whilst the lowest was observed at ZIS i.e. 2407.6 m3/ton. Cabbage had the lowest water footprint. The highest water footprint for growing cabbage was 254.5 m3/ton in TFIS, 223.1 m3/ton in TIS and the lowest was 217.8 m3/ton in ZIS. The differences observed in the WF of a crop at each scheme maybe attributed to the differences management, weather and environmental characteristics, in the three locations. Moreover, the needs for ET are related to soil type and plant growth, and primarily depend on crop development and climatic factors which are closely related to climatic demands. The grey water footprint was calculated using the recommended fertilizer application rates for all the three sites. Green beans had the highest WFgrey i.e. 373 m3/ton and the lowest was cabbage with 37 m3/ton. Potato, spinach and tomatoes had 156 m3/ton, 214 m3/ton and 132 m3/ton, respectively. Grey water footprint in this study was higher as compared to other studies, possibly because of the high rates of nitrogen fertilizers used in the calculations and the low yields farmers get. Compared with estimates from other studies, the water footprints of vegetable production within smallholder irrigation schemes was relatively high. There is therefore, a need to focus on crop management and tillage practices that will help in increasing yield while minimizing water usage.

Using energy more efficiently is essential if carbon emissions are to be reduced. According to the International Energy Agency (IEA), energy efficiency improvements represent the largest and least costly savings in carbon emissions, even when compared with renewables, nuclear power and carbon capture and storage. Yet, how should future priorities be directed? Should efforts be focused on light bulbs or diesel engines, insulating houses or improving coal-fired power stations? Previous attempts to assess energy efficiency options provide a useful snapshot for directing short-term responses, but are limited to only known technologies developed under current economic conditions. Tomorrow's economic drivers are not easy to forecast, and new technical solutions often present in a disruptive manner. Fortunately, the theoretical and practical efficiency limits do not vary with time, allowingthe uncertainty of economic forecasts to be avoided and the potential of yet to be discovered efficient designs to be captured. This research aims to provide a rational basis for assessing all future developments in energy efficiency. The global fow of energy through technical devices is traced from fuels to final services, and presented as an energy map to convey visually the scale of energy use. An important distinction is made between conversion devices, which upgrade energy into more useable forms, and passive systems, from which energy is lost as low temperature heat, in exchange for final services. Theoretical efficiency limits are calculated for conversion devices using exergy analysis, and show a 89% potential reduction in energy use. Efforts should befocused on improving the efficiency of, in relative order: biomass burners, refrigeration systems, gas burners and petrol engines. For passive systems, practical utilisation limits are calculated based on engineering models, and demonstrate energy savings of 73% are achievable. Significant gains are found in technical solutions that increase the thermal insulation of building fabrics and reduce the mass of vehicles. The result of this work is a consistent basis for comparing efficiency options, that can enable future technical research and energy policy tobe directed towards the actions that will make the most difference.

Producing steel causes 6% of global anthropogenic carbon dioxide emissions. Experts recommend that these emissions are reduced by half by the year 2050 in order to avert the worst consequences of climate change. Demand for steel is predicted to double in the next 36 years, meaning that a 75% reduction in emissions per unit of steel produced is necessary to reach the recommended limit. Process efficiency improvements cannot deliver this magnitude of reduction; however if steel is used more efficiently so that less new material is required to deliver the same service - a concept termed 'material efficiency' - then this could allow demand to be satisfied whilst emissions targets are achieved. Construction is the single largest use of steel globally, therefore using steel more efficiently in construction will reduce emissions. Three material efficiency strategies are identified as having most potential for this industry: using less material, using products for longer, and reusing components. In order to prioritise areas for research, steel flows into construction are mapped, finding that industrial buildings and utility infrastructure are the largest users of steel, while superstructure is confirmed as the main use of steel in a typical building. To estimate the potential to use less steel in buildings, 23 steel-frame designs are studied, sourced from three leading design consultancies. The utilisation of each element is found and the building datasets are analysed to infer the amount of steel over-provided. The results suggest that such buildings contain almost twice as much steel as necessary for structural performance, and indicate that this amount of over-provision occurs to minimise labour costs, which are a larger proportion of total costs than materials. To investigate how buildings and infrastructure could be used for longer, reasons for their failure are reviewed. Based on interviews with industry professionals a set of strategies is proposed, tailored to each failure cause and distinguishing between cases where failure can and cannot be reasonably foreseen. Steel sections could be reclaimed from old buildings and reused in new buildings but this does not occur because they are damaged during demolition. Designing for deconstruction would facilitate reuse but is not practised due to its cost. Data from interviews and a commercial working group are analysed to identify three aspects of designing for deconstruction that provide financial and operational benefits to clients, thus encouraging their use. One remaining technical barrier to deconstruction is composite steel-concrete systems, where welded connectors make it impractical to separate the steel beam from the concrete slab without damage. A novel bolted composite connector is proposed and tested in three beam experiments. The bolted connector allows successful separation of the components, facilitating reuse. Its structural performance is similar to that of welded connectors and can be predicted using current design standards. Each of the investigations reveals significant opportunities to reduce steel use in construction by using material more efficiently. Achieving these savings would reduce demand for new steel production and thereby decrease carbon dioxide emissions.

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Carbohydrates have variable digestibilities and metabolizable energy values in carnivorous fish. Simple sugars are generally more digestible than complex polysaccharides, and low levels of dietary carbohydrate may contribute more metabolizable energy than high levels. Two experiments were conducted to study the effects of dietary level and processing treatment of wheat starch on the digestibility of diets fed to sablefish (Anoplopoma fimbria), in different regions of the digestive tract. Moreover, an experiment was undertaken to determine if the dietary concentration of an indigestible external marker (chromic oxide) influenced its motility, relative to other ingredients in the ingesta, as it passed through the digestive tract. Lastly, a growth experiment was undertaken to compare the performance of sablefish fed formulated diets containing one of two levels of carbohydrate to that of fish fed a natural fish diet. The gastric evacuation of a formulated and a natural diet were also investigated. Apparent digestibility values for the nutrients in a formulated diet (containing 44.4% cooked wheat and 0.1% chromic oxide) fed to sablefish were noted to increase progressively from the anterior to the posterior regions of the intestinal tract. Within each region of the gut, the apparent digestibility values for most nutrients declined over three sample periods. Carbohydrate (nitrogen-free extract) digestibility down to the distal section of the intestine ranged from 51.0 to 82.8%. An experiment designed to assess the effect of carbohydrate treatment on the digestibility of four isonitrogenous, isocaloric diets met with partial failure. It was determined that the 1.0% chromic oxide marker flowed at a differential rate to the rest of the ingesta in the digestive tract, which violated the criteria for an effective marker. Consequently, diet digestibility was not determined in this experiment. Hepatic glycogen levels in fish receiving the dietary treatments were compared, and these values were used to estimate the relative availability (digestibility) of carbohydrate from the respective diets. According to this index, the sequence for digestibility was as follows: pregelatinized starch > cooked wheat > pregelatinized starch/cooked wheat > unprocessed wheat. Differential movement of chromic oxide relative to other ingesta was observed in sablefish fed on alternate days regardless of the dietary concentration of the indigestible marker (0.1 or 1.0%). It was surmised that the feeding protocol established the circumstances from which marker 'streaming' was observed in the results. Differential transport of Cr₂O₃ through the gut by ingested seawater was suggested as a possible mechanism for the phenomenon. Sablefish fed a natural fish diet had the highest growth rates, condition factors, liver lipid levels and the lowest feed conversion ratios and liver glycogen levels. Sablefish fed a diet containing 22.2% cooked wheat had a higher growth rate, condition factor, and a lower food conversion ratio, than those fed a diet containing 44.4% cooked wheat. Ingestion of the 44.4% cooked wheat diet resulted in the highest values for liver glycogen and hepatosomatic index. It was concluded that sablefish have a limited ability to metabolically utilize digestible carbohydrate and that most of the dietary non-protein energy should originate from high quality lipid for maximum protein sparing. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate