Water quality management for agricultural production is a complicated and interesting problem. Hydrological and economic factors must be considered when designing strategies to reduce nutrient runoff from agricultural activities. This dissertation is composed of three chapters that investigate cost-effective ways to mitigate water pollution from agricultural nonpoint pollution sources and explore farmers' incentives when participating in water quality trading programs. Chapter 1 investigates landscape targeting of best management practices (BMPs) based on topographic index (TI) to determine how targeting would affect costs of meeting nitrogen (N) loading goals for Mahantango watershed, Pennsylvania. We use the results from two climate models and the mean of the ensemble of seven climate models to estimate expected climate changes and the Soil and Water Assessment Tool-Variable Source Area (SWAT-VSA) model to predict crop yields and N export. Costs of targeting and uniform placement of BMPs across the entire study area (4.23 km2) are compared under historical and future climate scenarios. We find that with a goal of reducing N loadings by 25%, spatial targeting methods could reduce costs by an average of 30% compared with uniform BMP placement under three historical climate scenarios. Cost savings from targeting are 38% under three future climate scenarios. Chapter 2 scales up the study area to the Susquehanna watershed (71,000 km2). We examine the effects of targeting the required reductions in N runoff within counties, across counties, and both within and across counties for the Susquehanna watershed. We set the required N reduction to 35%. Using the uniform strategy to meet the required N reduction as the baseline, results show that costs of achieving a regional 35% N reduction goal can be reduced by 13%, 31% and 36% with cross-county targeting, within-county targeting and within and across county targeting, respectively. Results from Chapters 1 and 2 suggest that cost effectiveness of government subsidy programs for water quality improvement in agriculture can be increased by targeting them to areas with lower N abatement costs. In addition, targeting benefits are likely to be even larger under climate change. Chapter 3 investigates the landowner's nutrient credit trading behavior when facing the price uncertainty given the credits are allowed to be banked for future use. A two-step decision model is used in this study. For the first step, we determine the landowner's application level of a BMP on working land in the initial time period. The nutrient credits awarded to the landowner depend on the nutrient reduction level at the edge of field generated by the BMP application. For the second step, we use an intertemporal model to examine the landowner's credit trading behavior with stochastic price fluctuations over time and with transaction costs. The theoretical framework is applied with a numerical simulation incorporated with a hydro-economic model and dynamic programming. Nutrient Management (NM) is selected as the BMP on working land to generate N credits. We find that gains to the landowner from credit banking increase with higher price volatility and with higher price drift, but that gains are larger with price volatility. However, for a landowner holding a small amount of nutrient credits, the gains from credit banking are small due to transaction costs. / Doctor of Philosophy / Two considerations are critical for efforts to mitigate nutrient runoff from nonpoint sources: cost effectiveness of strategies to reduce nutrient runoff and landowners' incentives to participate in these programs. This dissertation is composed of three manuscripts, aiming to evaluate the cost effectiveness of government subsidy programs for water quality management in agriculture and investigate the landowner's incentives to participate in water quality trading programs for the Chesapeake Bay watershed. Chapter 1 investigates gains from targeting Best Management Practices (BMPs) under current and future climate conditions based on the soil characteristics relative to uniform BMP application for a small experimental watershed (4.23km2). Chapter 2 scales up the study area to a 71,000 km2 watershed and treats each county within the watershed as a representative farm to explore economic gains from targeting within county and across county based on counties' physical conditions and agricultural patterns. Both Chapters show that cost-effectiveness of government subsidy programs can be improved by spatial targeting BMPs to areas with lower abatement costs. Gains from targeting increase under climate change. In Chapter 3 we shows how a landowner's revenues from nutrient credit selling will be affected if the credits are allowed to be banked for future use when she faces price uncertainty. We find that gains to the landowner from credit banking increase more with higher price volatility than with higher price drift. Gains from banking are largely reduced by transaction costs associated with trading.

p. 1-146 / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-04-23T18:50:56Z No. of bitstreams: 1 1111A.pdf: 933472 bytes, checksum: 178184c8d9124f9c72f181505bf2071b (MD5) / Approved for entry into archive by Maria Creuza Silva(mariakreuza@yahoo.com.br) on 2013-05-04T16:50:05Z (GMT) No. of bitstreams: 1 1111A.pdf: 933472 bytes, checksum: 178184c8d9124f9c72f181505bf2071b (MD5) / Made available in DSpace on 2013-05-04T16:50:05Z (GMT). No. of bitstreams: 1 1111A.pdf: 933472 bytes, checksum: 178184c8d9124f9c72f181505bf2071b (MD5) Previous issue date: 2007 / A importância das relações do homem com o meio ambiente e seus impactos na saúde da população levou o Ministério da Saúde a estruturar a vigilância em saúde ambiental no Brasil, no âmbito do Sistema Único de Saúde (SUS). Ela vem sendo operacionalizada por meio do Subsistema Nacional de Vigilância em Saúde Ambiental (SINVSA). Com objetivo de contribuir para o fortalecimento deste subsistema, o presente estudo se propôs a elaborar um modelo lógico do SINVSA baseado na experiência profissional da própria autora e em uma análise crítica da percepção de seus gestores federais quanto à concepção e operacionalização da Vigilância em Saúde Ambiental no SUS. Para tanto se realizou uma pesquisa qualitativa de natureza exploratória descritiva. Os dados foram coletados mediante análise documental e entrevistas semi-estruturadas com 11 informantes-chave provenientes da Coordenação Geral de Vigilância em Saúde Ambiental, da Secretaria de Vigilância em Saúde do Ministério da Saúde, a quem compete a gestão federal do SINVSA. Após sistematização dos dados coletados referentes a percepção dos informantes procedeu-se a análise do material usando-se a técnica de análise de discurso, cujas categorias analíticas constituíram-se na práxis e concepção. Estas categorias foram operacionalizadas em diversas dimensões, que expressavam a percepção dos gestores do Subsistema quanto sua concepção e operacionalização, servindo de base à elaboração do modelo lógico proposto, o qual foi denominado modelo lógico condutor do SINVSA. Além disso, foi possível descrever a construção da vigilância em saúde ambiental no Brasil e seu contexto sócio-histórico. / Salvador

This thesis describes the accounting's and auditing's systems in Vietnam. The Vietnamese regulations and legilations are particularly emphased in great details as the important components of the accounting and auditing systems. On the other hand, it, also, focuses on the financial statements for the business and its audit as well as the struture of equity and types of investments for allied companies.

Made available in DSpace on 2017-07-10T17:11:48Z (GMT). No. of bitstreams: 1 Dissertacao Mariana Uzeda2.pdf: 3273824 bytes, checksum: cb0d125fc8aae9dfe673029b5f5a30a5 (MD5) Previous issue date: 2014-08-29 / This work presents a comparative study between four different sliding mode variable structure control strategies (SMVSC) applied to autonomous underwater vehicles (AUV) positioning in 6 DOF, under the influence of wind, waves and marine currents. The addressed strategies are the conventional CEV-MD control based on Lyapunov stability, the CEV-MD control based on the equivalent control, the CEV-MD control based on the input-output stability and the CEVMD adaptive control. The accomplished comparisons seek a satisfactory tradeoff between the tracking performance and the closed-loop system stability in light of eliminating the chattering phenomenon. In that sense, the analysis and synthesis of the respective SMVSC control laws is carried out fromthe Lyapunov Stability Theory and the Barbalat s Lemma. As well as numerical simulations are implemented to obtaining the respective performances of each SMVSC control strategy presented. / Este trabalho apresenta um estudo comparativo entre quatro diferentes estratégias de controle de estrutura variável por modos deslizantes (CEV-MD) aplicadas ao posicionamento de veículos subaquáticos autônomos (VSA) em 6 GDL, sob a influência de ventos, ondas e correntes marinhas. As estratégias abordadas são o controle CEV-MD convencional baseado na estabilidade de Lyapunov, o controle CEV-MD baseado no controle equivalente, o controle CEV-MD baseado na estabilidade entrada-saída e o controle CEV-MD adaptativo. As comparações realizadas visam a eliminação do do fenômeno do chattering buscando um compromisso satisfatório entre o desempenho de rastreamento e a estabilidade do sistema em laço fechado. Nesse sentido, a análise e síntese das respectivas leis de controle CEV-MD é realizada a partir da Teoria de Estabilidade de Lyapunov e do Lema de Barbalat. Assim como simulações numéricas são implementadas para a obtenção dos respectivos desempenhos de cada estratégia de controle CEV-MD apresentada.

This work focuses on fixing measurement inaccuracies to which models and figures of merit are susceptible in two wireless communication environments: power amplifier and multipath. To emulate or rate the performance of these environments, models and figures of merit, respectively, are often used. The usefulness of a model depends on how accurately and efficiently it emulates its real-world counterpart. The usefulness of a figure of merit depends on how accurately it represents system behavior. Most discussions on the challenges and trade-offs faced in modeling nearly always focus on the complexity of the device or channel of interest and the resultant difficulty in describing it. Similarly, figures of merit are meant only to summarize the performance of the device or channel. At some point, either in generation or verification of a model or figure of merit, there is a dependence on measured data. Though the complexity and performance of the device or channel are challenges by themselves, there are other significant sources of distortion that must be minimized to avoid errors in the measured data. For this work, the unique distortion of power amplifier and multipath environments is considered, and then errors in measurement which would obscure these distortions are eliminated. Specifically, three measurement issues are addressed: 1) identifying measurement setup artifacts, 2) achieving consistent measurement results and 3) reducing variations in the environment. This work contributes to increasing the accuracy of microwave measurements used in the modeling of nonlinear high-power amplifiers and used in figures of merit for power amplifiers and multipath channels.

This study investigates different ways of efficiently educating learners to become bi- or multilingual. In the introduction relevant background information concerning the definition of bilingualism is given and related issues are being discussed, such as language learning, language awareness, bilingual instruction and bilingual education models. Human beings are characterised by language, but also by social and cultural tradition. In the context of globalisation pluralism and multiculturalism are common factors affecting even previously isolated communities. Bi- and multilingualism are some of the strategies of adaptation to this reality. It can be assumed, that this development will continue rapidly as the inhabitants of the global village grow in and adapt to this realisation. In countries with a history and tradition of multilingual and bilingual education like South Africa, Canada, Luxembourg and Belgium and also in countries where immigration results in issues of multilingual and bilingual challenging society like in the USA one finds a great variety of answers to these problems posed. The situation in Germany is different, because bilingualism became an issue only fairly recently due to the actual demands brought by the European union. In South Africa the social context determines largely that people are inclined to bi- and multilingualism and the educational system tries to promote this predisposition by means of bi- or multilingual models in schools, so that the learners become efficient facing the bi- and multilingual challenges of their diverse and pluralistic society. In the USA on the other hand the need arises to provide for minority groups, so that they can retain their mother tongue (e.g. Spanish) while becoming fluent in the predominant language (i.e. American). Lastly the new development of the European Union has led Germany to actively promote bi- und multilingual education to aid the integration of Germans in the Union. The various models developed in these countries are studied in the wide variety of their different social and historical contexts. The main part of the study comprises a systematic overview of the various bilingual education models that are being implemented in different countries. These countries include the USA, Canada, Germany, Luxembourg, Belgium and lastly and more detailed, South Africa. A number of different circumstances surrounding bi- or multilingualism in the various countries have given rise to a large variety of models attempting to address the challenges posed by the various issues. A number of different goals have been addressed and the results have been just as varied. This leads to a concluding comparison of the western and European models with those of the South African models. Much research has been done on bi- and multilingualism and specifically bilingual education, as humans since earliest times were concerned with this subject. For my study I have relied mainly on more recent sources (1990 to the present) from the USA, Canada and Germany. However as the academic study of this issue has been going on for quite a time in some countries like South Africa, I have also referred to older books and journals (1945<). Due to the overwhelming information about this subject a drastic limitation of sources was necessary. / Dissertation (MA (German))--University of Pretoria, 2005. / Modern European Languages / unrestricted

The paper focuses on the issue of access control. It presents an universal bilateral protocol of access control of ACP. The paper describes the messages and its sequences that AC portals uses for communication. It describes the functions and features of the modules from which the portal is composed. The paper suggests the concept of a modular AC portal solutions including the design of basic modules. It also outlines possible test scenarios. Under this proposal is generated functional AC portal on the .NET Framework platform using the C\# programming language. The portal provides access to local assets or to the assets on other computers in the local network. Created application is tested according to the scenarios proposed in both the network version and the local version of the AC portal. Test results are objectively evaluated and commented.

Radio astronomy is the science of observing the heavens at radio frequencies, from a few kHz to approximately 300 GHz. In recent years, radio astronomy has faced a growing interference problem as radio frequency (RF) bandwidth has become an increasingly scarce commodity. A programmable real-time DSP least-mean-square interference canceller was developed and demonstrated as a successful method of excising satellite down-link signals from both an experimental platform at BYU, and the Green Bank Telescope at the National Radio Astronomy Observatory in West Virginia. A performance analysis of this cancellation system in the radio astronomy radio frequency interference (RFI) mitigation regime constitutes the main contribution of this thesis. The real-time BYU test platform consists of small radio telescopes, low noise RF receivers, and a state-of-the-art DSP platform. This programmable real-time radio astronomy RFI mitigation tool is the first of its kind. Basic tools needed for radio astronomy observations and the analysis and implementation of interference mitigation algorithms were also implemented in the DSP platform, including a power spectral density estimator, a beamformer, and an array signal correlator.