With the world’s population set to reach 9 billion by the mid 21st century food security has never been more important. Increased competition regarding land for agricultural use and over fished seas means it falls to aquaculture to meet the global demands for protein requirements. The largest supply of aquaculture products are cultivated in South East Asia where the industry has seen rapid expansion, particularly of pond production in the past 50 years. This initial expansion has come at a cost with mangrove losses and eutrophication of natural water sources resulting. The impact of these not only affects other stakeholders, including domestic users, but effects will be felt by the aquaculture industry. Indiscriminate release of effluents to the surrounding water reduces the water quality for other users and may impact on the farm discharging the water originally. Poor water quality can then result in poor growth rates and increased mortalities reducing the profitability of the farm and endangering the livelihood of the farmer. If aquaculture is to meet the global food demand it is important that current and future enterprises are developed with sustainability at the fore front. This study investigates the nutrient dynamics in pond culture in South East Asia, focussing initially on four countries outlined by the SEAT (Sustainable Ethical Aquaculture Trade) project, including Thailand, Vietnam, China and Bangladesh. Within the four countries the main species cultured for export were identified resulting in tilapia, shrimp, pangasiid catfish and prawn. Following a farmer survey designed to collect a large volume of data over a range of topics including, water management, social, economic and ethical perceptions, dynamic models were developed, using Powersim Studio 8© (Powersim, Norway), for a generic fish and shrimp ponds separately. The models draw on data from the survey combined with other literature sources to provide outputs for Total Nitrogen and Total Phosphorus in water and sediment as well as dissolved oxygen in the pond water. One of the biggest challenges facing this study was the objective selection of relevant sites for case studies to apply the models to. With such a large preselected set of sites (200 per species per country) it was important that the method be capable of handling such large datasets. Thusly it was decided that a multivariate method be used due to the removal of any pre judgement of the data relevant to the study. In order to investigate the nutrient dynamics water management data was used in the multivariate analysis to identify any similarity between the practices occurring on farms. The case studies in this project focus on Thailand and Vietnam, covering tilapia, shrimp and pangasius. Prawn farms were disregarded as, through the survey, it was discovered most production was for domestic trade. The models were adapted to each farm case study expanding the boundary from pond level to farm level, providing an output for each pond in terms of nutrients in the water and production levels and the farm as a whole for dissolved oxygen and sediment accumulation. The results of the models suggest the culture species to be taking up much of the TN added followed by the accumulation in sediments in shrimp ponds, while TP is mostly taken up by sediments. The fish case studies suggest that most of the TN is discharged to the environment followed by uptake. While Total phosphorus shows similar results to shrimp, accumulating in the sediment. The models presented in this study can be used to estimate outputs from farms of similar water management strategies and can assist in the determination of where improvements can be made to reduce the potential for eutrophication of natural water sources.

The UK has a large and growing inventory of higher activity radioactive waste awaiting safe long term disposal. The international consensus is to dispose of this radioactive and toxic waste within a deep geological repository, situated 200-1,000 metres beneath the ground surface. The deep geological disposal facility is designed to be a series of engineered and natural barriers. Groundwater forms an integral component of the natural barrier because it 1) controls the flux of reactive components towards the engineered repository, and 2) forms one of the primary transport mechanism through which released radionuclides can be transported away from the repository. The timescale of protection provided by the natural barrier exceeds those provided by the engineered barriers. Knowledge of the regional hydrogeology is a vital step towards predicting the long term performance of any potential repository site. Topically, a UK government decision in 2017 to re-open a nation-wide repository location search has now created a renewed mandate for site exploration. This research aims to determine the regional groundwater characteristics of three UK settings, selected to be hydrogeologically distinct, in order to determine which, if any, offers natural long term hydrogeological containment potential. The settings selected for analysis include Sellafield in West Cumbria, the Tynwald Basin within the East Irish Sea Basin, and Thetford within East Anglia. Site selection is based on diverse groundwater characteristics, and on previous research suggesting potential hydrogeological suitability at these locations. This research is novel in that it provides, for the first time, a direct comparison between the characteristics and qualities of different regional groundwater settings to contain and isolate radioactive waste, based on UK site specific data. Large and detailed numerical models for the three sites, covering areas of 30 km length by 2- 4 km depth have been developed using the open source finite element code 'OpenGeoSys'. The models couple the physical processes of liquid flow and heat transport, in order to replicate regional scale groundwater flow patterns. Models are calibrated to measured rock properties, and predict groundwater behaviour 10,000 years into the future. Uncertain parameter ranges of lithological and fault permeabilities, and peak repository temperatures are tested to determine the possible range of groundwater outcomes. Geochemical retention is assessed separately and validated using the finite difference modelling software 'GoldSim'. Worst case groundwater characteristics for containment and isolation at each site are compared to an 'ideal' benchmark far-field hydrogeological outflow scenario, and scored accordingly using a newly proposed method of assessment. Results show that the Tynwald Basin offers the best potential of the three sites for natural radionuclide containment, performing between 3.5 and 4 times better than Sellafield, and between 1.7 and 4 times better than Thetford. The Tynwald Basin is characterised by 1) long and deep groundwater pathways, and 2) slow local and regional groundwater movement. Furthermore, the Tynwald Basin is located at a feasible tunnelling distance from the coast, adjacent to the UK's current nuclear stockpile at Sellafield, and thus could provide a simple solution to the current waste legacy problem. Results from the Sellafield model indicate that this location cannot be considered to exhibit beneficial characteristics due to short and predictable groundwater pathways which ascend, from the repository, towards surface aquifers. Finally, Thetford within East Anglia has never been drilled to depth so that sub-surface rock properties of basement, located beneath layered sediments, are based on evidence inferred from around the UK. Uncertainties in rock properties has produced a wide range of groundwater characteristic possibilities, with results indicting prospective performance to range from 0 to 2.4 times better than Sellafield. As such, the hydrogeological suitability to host a potential deep geological repository is promising when modelled with most-likely permeability values, but cannot be accurately determined at present. Consideration of decaying heat from the heat emitting waste packages at the three sites reveal that the natural groundwater flow patterns can be distorted up to as much as 7 km away from the theoretical repository, depending on setting. This thus changes the use of the term 'near-field' for safety assessments, as implying an area within the immediate vicinity of the excavated repository site. The overarching findings from this research are that: 1) some locations have greater long term radionuclide containment and isolation prospectivity than others, due to variable quality far-field geological and hydrogeological characteristics; 2) the effect of radiogenic heat emission on the natural groundwater flow pattern is dependent on the site specific geological and hydrogeological characteristics, and therefore so is the area defined as the 'near-field'; and 3) a simple method of site comparison is possible for regional groundwater system under steadystate conditions. Recommendations are for scoping models of regional groundwater settings to be used as a comparative tool, such as undertaken as part of this research, to differentiate between potential sites at an early stage of the current UK site selection programme.

<p>This thesis focuses on a black-tailed godwit (<i>Limosa limosa</i>) population, consisting of 35-40 pairs, that breeds on a grazed shore meadow on SE Gotland, Sweden. The small size of the population makes it more prone to extinction due to chance events, than a larger population.</p><p>The godwits showed microhabitat preferences when choosing nest sites. Godwit nests had higher vegetation over the nest cup, lower surrounding (1-3 m) vegetation and different plant species composition, as compared to random sites. Breeding near conspecifics or other wader species, especially lapwings (<i>Vanellus vanellus</i>) and further away from potential predator perches were the most important factors in decreasing nest predation. A comparison between different shore meadows along the east coast of the island revealed that large, open areas suffered less from nest predation. Thus, shore meadows suitable for breeding godwits should be large and without trees or other predator perches and have a grazing regime that favours variation in vegetation height.</p><p>Over 80% of previously ringed adults returned each year, but very few birds ringed as chicks were recovered. Hatching success was 55-60% for all observed nests. To predict the future of the current population, demographic data were used in an ecological risk analysis. The simulations showed that the Gotlandic population will not survive the coming 40 years without immigration.</p><p>Black-tailed godwits are divided into three subspecies. Genetic analyses (mtDNA) revealed that all subspecies had unique haplotypes and there was a clear geographic structure among subspecies. Within the <i>limosa</i> subspecies, godwits on Gotland and Öland showed a high proportion of rare haplotypes, but no genetic variation was found in Dutch birds. These results imply that black-tailed godwits on Gotland and Öland have high conservation value.</p>

This thesis studies connections between disorder type in tree polymers and the branching random walk and presents an application to swarm site-selection. Chapter two extends results on tree polymers in the infinite volume limit to critical strong disorder. Almost sure (a.s.) convergence in the infinite volume limit is obtained for weak disorder by standard theory on multiplicative cascades or the branching random walk. Chapter three establishes results for a simple branching random walk in connection with a related tree polymer. A central limit theorem (CLT) is shown to hold regardless of polymer disorder type, and a.s. connectivity of the support is established in the asymmetric case. Chapter four contains a model for site-selection in honeybee swarms. Simulations demonstrate a trade-off between speed and accuracy, and strongly suggest that increasing the quorum threshold at which the process terminates usually improves decision performance. / Graduation date: 2013

This thesis focuses on a black-tailed godwit (Limosa limosa) population, consisting of 35-40 pairs, that breeds on a grazed shore meadow on SE Gotland, Sweden. The small size of the population makes it more prone to extinction due to chance events, than a larger population. The godwits showed microhabitat preferences when choosing nest sites. Godwit nests had higher vegetation over the nest cup, lower surrounding (1-3 m) vegetation and different plant species composition, as compared to random sites. Breeding near conspecifics or other wader species, especially lapwings (Vanellus vanellus) and further away from potential predator perches were the most important factors in decreasing nest predation. A comparison between different shore meadows along the east coast of the island revealed that large, open areas suffered less from nest predation. Thus, shore meadows suitable for breeding godwits should be large and without trees or other predator perches and have a grazing regime that favours variation in vegetation height. Over 80% of previously ringed adults returned each year, but very few birds ringed as chicks were recovered. Hatching success was 55-60% for all observed nests. To predict the future of the current population, demographic data were used in an ecological risk analysis. The simulations showed that the Gotlandic population will not survive the coming 40 years without immigration. Black-tailed godwits are divided into three subspecies. Genetic analyses (mtDNA) revealed that all subspecies had unique haplotypes and there was a clear geographic structure among subspecies. Within the limosa subspecies, godwits on Gotland and Öland showed a high proportion of rare haplotypes, but no genetic variation was found in Dutch birds. These results imply that black-tailed godwits on Gotland and Öland have high conservation value.

I conducted this study to better understand the greater roadrunner’s (Geococcyx californianus) spatial use, nest site selection, and sexual morphometrics. Data were first collected from a roadrunner population in Fisher County, Texas. I trapped, measured, and removed feathers for sex confirmation through DNA PCR analysis. I then fit the roadrunners with a radio transmitter and released them at the capture site. I captured a total of 10 birds (1 male and 9 females) and triangulated the location of each bird 2-4 times per week from February to August 2011 during the roadrunner nesting season. The data produced a mean minimum convex polygon nesting range of 43.01-ha, a 50% core utilization distributions of 11.88-ha, and an overlap index of 33.05 percent. Habitat selection ratios showed a preference for ridge as well as grassland habitat and avoidance of bare ground and flatland habitats. The location data from west Texas was further analyzed to build a predictive logistic regression model to understand the significant site characteristics in roadrunner land use during the nesting season. It was determined that percent rock (-0.12, P = 0.0001) and percent litter (-0.05, P = 0.0052) were the best predictors in determining actual from random locations. Rock references open area for hunting, transportation as well as ridge habitat. Litter alludes to region below dense stands of shrubs and is used by roadrunners for evasion from threats and as shade for thermoregulation. The measurements from the roadrunners in west Texas as well as museum specimens from across their natural range were combined to develop an easy, inexpensive, and field-relevant sex identification model. The strongest model consisted of bill depth (0.79, P< 0.0001) and bill tip to the back of the head (0.05, P = 0.1573) which were both found to be larger in males. The final portion of this study concerned roadrunner nest site selection. Data were collected in Wilbarger County, Texas from May 2006 to October 2009. A predictive logistic regression model of nesting locations determined that mesquite nesting tree (-0.89, P = 0.0064), oval tree shape (1.58, P = 0.0118), mesquite density (-0.004, P = 0.0080), and topographic edge (1.37, P = 0.0027) were the best predictors in determining actual nest sites from random locations.

The main scope of this thesis is to select alternative landfill sites for Ankara based on the growing trends of Ankara towards the Sincan and G&ouml / lbaSi municipalities and to eventually select the best alternative. Landfill site selection was carried out utilizing Geographic Information System (GIS) and Multi-Criteria-Decision-Analysis (MCDA). A number of criteria were gathered in a GIS environment. Each criterion was assigned a weight value by applying the Pairwise Comparison Method (PCM). &ldquo / The Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS)&rdquo / , was applied and the best landfill site alternative was determined. The geotechnical properties of the clay samples, obtained from selected locations in G&ouml / lbaSi and Sincan were determined in order to design a landfill liner system using compacted &ldquo / Ankara Clay&rdquo / as the liner material. The permeability values for the clay samples were determined by performing falling head tests and consolidation tests. The coefficient of permeability value of the compacted clay was determined to be in the order of 10-10 m/s for the G&ouml / lbaSi samples and 10-11 m/s for the Sincan samples for both of the tests performed. These tests indicated that the native clay was suitable to be utilized as a landfill liner material. The HELP and POLLUTE was employed for the purpose of landfill design and predicting the landfill hydrological processes. The landfill profile with a double lining system composed of geomembrane/compacted clay composite top and bottom liners with a drainage layer was determined to show the best performance amongst the others.

Enabling more than one function in an entity provides a new cost-effective way to develop a highly reliable system. In this dissertation, we study the reliability of systems containing multi-functional entities. We derive the expressions for reliability of one-shot systems and reliability of each function. A step further, a redundancy allocation problem (RAP) with the objective of maximizing system reliability is formulated. Unlike constructing a system with only single-functional entities, the number of copies of a specific function to be included in each multi-functional entity (i.e., functional redundancy) needs to be determined as part of the design. Moreover, a start-up strategy for turning on specific functions in these components must be decided prior to system operation. We develop a heuristic algorithm and include it in a two-stage Genetic Algorithm (GA) to solve the new RAP. We also apply a modified Tabu search (TS) method for solving such NP-hard problems. Our numerical studies illustrate that the two-stage GA and the TS method are quite effective in searching for high quality solutions. The concept of multi-functional entities can be also applied in probabilistic site selection problem (PSSP). Unlike traditional PSSP with failures either at nodes or on edges, we consider a more general problem, in which both nodes and edges could fail and the edge-level redundancy is included. We formulate the problem as an integer programming optimization problem. To reduce the searching space, two corresponding simplified models formulated as integer linear programming problems are solved for providing a lower bound to the primal problem. Finally, a big challenge in reliability analysis is how to determine the failure distribution of components. This is especially significant for multi-functional entities as more levels of redundancy are considered. We provide an automated model-selection method to construct the best phase-type (PH) distribution for a given data set in terms of the model complexity and the adequacy of statistical fitting. To efficiently utilize the Akaike Information Criterion for balancing the likelihood value and the number of free parameters, the proposed method is carried out in two stages. The detailed subproblems and the related solution procedures are developed and illustrated through numerical studies. The results verify the effectiveness of the proposed model-selection method in constructing PH distributions.

Orientador: Paulina Setti Riedel / Banca: Paulo Milton Barbosa Landim / Banca: Diana Sarita Hamburger / Resumo: O presente trabalho, desenvolvido no município de Americana, estado de São Paulo, teve como objetivo avaliar a adequabilidade à disposição de resíduos sólidos através da utilização dos métodos da lógica Difusa, comparando-os aos resultados obtidos através da aplicação da análise booleana e da análise multicriterial ponderada, gerados por ARAÚJO(1999). As variáveis utilizadas na análise foram: permeabilidade relativa, capacidade de troca catiônica (CTC), potencial hidrogeniônico (pH), profundidade do lençol freático, espessura do material inconsolidado, declividade, distância das áreas urbanas, distância das estações de captação de água, distância dos principais corpos d'água e distância das áreas de proteção ambiental. Os resultados obtidos foram discutidos em termos de vantagens de aplicação dos métodos e mostraram que as áreas com adequabilidade crescente à disposição de resíduos sólidos, encontradas através dos métodos de lógica Difusa, são territorialmente mais restritas que as obtidas pelos métodos mais tradicionais. Dentre os operadores Difusos, o mais otimista foi o Operador Difuso Máximo, enquanto que o Gama Difuso o mais restritivo, os demais operadores produziram mapas intermediários. Entretanto, o mapa gerado a partir do Operador Difuso Mínimo pode ser empregado em posteriores estudos voltados à seleção de áreas para disposição de resíduos sólidos. / Abstract: This study, developed in the municipal district of Americana, São Paulo State, had the aim to evaluate the waste disposal suitability, through the application of fuzzy logic methods and to compare the obtained results to those generated by boolean analysis and weighted multi- criteria analysis, produced by ARAUJO (1999). The factors used were: relative permeability, pH scale, cationic exchange capacity, unconsolidated material thickness, static level depth, slope, distance from urban perimeter, distance from water reservoir, distance from city water source and from environmental protection areas. The obtained results were discussed based on the advantages and disadvantages of the applied method and showed that the indicated areas with increasing suitability to waste disposal , produced by fuzzy logic methods, are smaller than those produced by the traditional methods. Comparing the different fuzzy operators used, the less restrictive one was the Fuzzy OR, on the other hand, the Gamma Operation was the most restrictive one and the others generated intermediary results. The map generated by the Fuzzy AND can be applied to further studies directed to site selection to waste disposal. / Mestre

In this study, increasing electricity demand requires considerable attention to increasing the diversity of power generation. Alternative energy can produce heating and power systems and thermal storage. Our objective and every organization’s objectives are to minimize its energy consumption cost under electricity demand uncertainty. In rural areas, heat and power availability and stability are also crucial. Combined heat and power have proven their effectiveness as a subsequent to Electricity. This paper identified four criteria and eleven sub-criteria to determine the most appropriate structure location for combined heat and power in the rural community. The Bayesian Network technology has been applied to analyze these criteria comprehensively. A case study including multiple sites across the Mississippi state was used to validate the proposed approach, and propagation and sensitivity analysis were used to evaluate performance. Results showed the summarized eleven criteria proposed Bayesian Network approach could aid location selection for Combined heat and power location in the rural area. Supplementary, the created model can support decision-makers to select the best alternatives under different electricity demand variability levels.