Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: A collaboration between the Katholieke Universiteit van Leuven (KUL) and Stellenbosch University (SU), resulted in the development of a satellite based platform for use in agricultural sensing applications. This will primarily serve as a test platform for a digitally beam-steerable antenna array (SAA) that was developed by KUL. SU developed all flight - and ground station based hardware and software, enabling ground to flight communications and interfacing with the KUL SAA. Although most components had already been completed at the start of this M:Sc:Eng: project, final systems integration was still unfinished. Modules necessary for communication were also outstanding. This project implemented an automatic repeat and request (ARQ) strategy for reliable file transfer across the wireless link. Channel coding has also been implemented on a field programmable gate array (FPGA). This layer includes an advanced forward error correction (FEC) scheme i.e. a low-density parity-check (LDPC), which outperforms traditional FEC techniques. A flexible architecture for channel coding has been designed that allows speed and complexity trade-offs on the FPGA. All components have successfully been implemented, tested and integrated. Simulations of LDPC on the FPGA have been shown to provide excellent error correcting performance. The prototype has been completed and recently successfully demonstrated at KUL. Data has been reliably transferred between the satellite platform and a ground station, during this event. / AFRIKAANSE OPSOMMING: Tydens ’n samewerkingsooreenkoms tussen die Katholieke Universiteit van Leuven (KUL) en die Universiteit van Stellenbosch (US) is ’n satelliet stelsel ontwikkel vir sensor-netwerk toepassings in die landbou bedryf. Hierdie stelsel sal hoofsaaklik dien as ’n toetsmedium vir ’n digitaal stuurbare antenna (SAA) wat deur KUL ontwikkel is. Die US het alle hardeware en sagteware komponente ontwikkel om kommunikasie d.m.v die SAA tussen die satelliet en ’n grondstasie te bewerkstellig. Sedert die begin van hierdie M:Sc:Ing: projek was die meeste komponente alreeds ontwikkel en geïmplementeer, maar finale stelselsintegrasie moes nog voltooi word. Modules wat kommunikasie sou bewerkstellig was ook nog uistaande. Hierdie projek het ’n ARQ protokol geïmplementeer wat data betroubaar tussen die satelliet en ’n grondstasie kon oordra. Kanaalkodering is ook op ’n veld programmeerbare hekskikking (FPGA) geïmplementeer. ’n Gevorderde foutkorrigeringstelsel, naamlik ’n lae digtheids pariteit toetskode (LDPC), wat tradisionele foutkorrigeringstelsels se doeltreffendheid oortref, word op hierdie FPGA geïmplementeer. ’n Kanaalkoderingsargitektuur is ook ontwikkel om die verwerkingspoed van data en die hoeveelheid FPGA logika wat gebruik word, teenoor mekaar op te weeg. Alle komponente is suksesvol geïmplementeer, getoets en geïntegreer met die hele stelsel. Simulasies van LDPC op die FPGA het uistekende foutkorrigeringsresultate gelewer. ’n Werkende prototipe is onlangs voltooi en suksesvol gedemonstreer by KUL. Betroubare data oordrag tussen die satelliet en die grondstasie is tydens hierdie demonstrasie bevestig.

This thesis examines the validity of the cost of carry model for pricing FTSE100 futures contracts and the relationship between FTSE100 spot and futures markets during two sub-periods characterised by different market trading systems employed by the LSE and LIFFE. The empirical work is carried out using three approaches to econometric modeling: a basic VECM for spot and futures prices, a VECM extended with a DCCTGARCH framework to account for the conditional variance-covariance structure for spot and futures prices and a threshold VECM to capture regime-dependent spot-futures price dynamics. Overall, both the basic VECM and the DCC-TGARCH analysis suggest that there are deviations from the cost of carry relationship in the first sub-sample when transactions costs in both markets are relatively high but that the cost of carry relationship tends to be valid in the second sub-sample when transactions costs are lower. This is further confirmed by the evidence of higher conditional correlations between the two markets in the second sub-sample as compared with the first, using the DCC-TGARCH analysis. This implies that the no-arbitrage cost of carry relationship between spot and futures markets is more effectively maintained by index arbitrageurs in the second period when market conditions are closer to perfect market assumptions, and hence the cost of carry model could be more reasonably used as a benchmark for pricing stock index futures. The threshold VECM analysis depicts regime-dependent price dynamics between FTSE100 spot and futures markets and leads to some interesting and important findings: arbitrage may not be practicable under some market conditions, either because it is difficult to find counterparties for the arbitrage transactions, or because there is significant risk associated with arbitrage; as a result, the cost of carry model may not always be suitable for pricing stock index futures. Furthermore, the threshold values yielded from estimating the threshold VECM reflect the average transaction costs for most arbitrageurs that are more reliable and fair than subjective estimations.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

This paper focuses on analysing and modelling inflation and its dynamics in Czech Republic applying a special kind of econometric models. Firstly economic theory of inflation is mentioned - fundamental terms, measuring methods of inflation, the way Czech national bank is monitoring the inflation and obviously a short summary of historical evolution of inflation in Czech economy. In the second part of this paper two econometric concepts of modelling time series are introduced - vector autoregression models (VAR models) and volatility models, concretely ARCH and GARCH models. In connection with the VAR models, Granger causality, impulse response functions, cointegration and error correction models are described. The empirical part includes application of selected models on real time series of chosen macroeconomic indicators. The estimation outputs are interpreted and forecasts are implemented. The quality of chosen econometric models for modelling inflation in Czech Republic is discussed.

The main purpose of this study is to empirically assess the relationship between inflation and economic growth in Ethiopia using quarterly dataset from 1992Q1 to 2010Q4. In doing so, an interesting policy issue arises. What is the threshold level of inflation for the Ethiopian economy? Based on the Engle-Granger and Johansen co-integration tests it is found out that there is a positive long-run relationship between inflation and economic growth. The error correction models show that in cases of short-run disequilibrium, the inflation model adjusts itself to its long-run path correcting roughly 40% of the imbalance in each quarter. In addition, based on the conditional least square technique, the estimated threshold model suggests 10% as the optimal level of inflation that facilitates growth. An inflation level higher or lower than the threshold level of inflation affects the economic growth negatively and hence fiscal and monetary policy coordination is vital to keep inflation at the threshold. / Economics / M. Com. (Economics)

O processamento de informação quântica requer medidas, muitas vezes precedidas devoluções unitárias. Uma descrição realista de um computador quântico também deve levar em conta que o sistema interage com um ambiente externo - distinto do observador - que o remove de sua evolução ideal, gerando erros. Neste trabalho, fazemos um estudo da dinâmica de sistemas quânticos observados múltiplas vezes ou continuamente, enquanto interagem com ambientes externos. Para tanto, empregamos uma equação mestra híbrida, que permite modelar uma interação contínua e markoviana do sistema com o medidor, enquanto o ruído do ambiente apresenta características não markovianas. O estudo da dinâmica de uma medida contínua ruidosa revela que o sistema melhor preserva suas populações iniciais quando é realizada a medida de uma observável que não comuta com os operadores do ruído produzido pelo ambiente. Estes resultados, já conhecidos para o caso simples de um qubit de memória interagindo com o vácuo, são generalizados para uma temperatura inicial superior a zero e para um qubit submetido a uma porta quântica. A universalidade destes fenômenos de preservação da população inicial permite fazer analogia com o efeito Zenão quântico. Mantendo o mesmo formalismo, mas adaptando a interação com o ambiente para descrever um decaimento verificamos que o efeito Zenão quântico é observado para acoplamentos fracos com o ambiente. Tratamos também de como tal conhecimento sobre a preservação das populações pela medida auxilia na elaboração de melhores formas de preservar a informação em códigos quânticos. Com o auxílio da teoria das medidas fracas, propomos um possível método experimental simples para o teste da validade dos modelos de descrição de medidas contínuas. Com este estudo da dinâmica de uma medida quântica, esperamos elucidar questões de ordem prática no processamento de informação quântica, assim como ajudar no melhor entendimento de questões fundamentais, como o postulado da medida. / The processing of quantum information requires measurements, often preceded by unitary evolutions. A faithful description of a quantum computer should also take into account that the system interacts with an external environment - other than the observer - that removes it from its ideal evolution, causing errors. Here, we study the dynamics of quantum systems observed multiple times or continuously, while they interact with external environments. To do this, we employ a hybrid master equation, which allows us to model a continuous, Markovian interaction between the system and the measurement apparatus, while the environmental noise presents non-Markovian features. This study of the dynamics of the noisy continuous measurement reveals that the system better preserves its initial populations when the observable measured does not commute with the environmental noise operators. These results, already known for the simpler case of a memory qubit interacting with vacuum, are generalized for an initial temperature above zero and a qubit undergoing a quantum gate. The universality of these phenomena of preservation of the initial populations allows an analogy with the Quantum Zeno Effect. Keeping the same formalism, but adapting the environmental interaction to describe a decay, we verify that the quantum Zeno effect is observed for weak coupling with the environment. We also deal with how the knowledge about the preservation of the populations by the measurement helps in creating better ways to preserve the information in quantum codes. With the help of the weak measurement theory, we propose a simple experimental method to test the validity of models that describe a continuous measurement. With this study of the dynamics of a quantum measurement, we hope to help solve practical issues in quantum information processing, as well as provide greater insight into fundamental questions, such as the measurement postulate.

A segmentação dos mercados internacionais permite a existência do pricing-to-market, hipótese inicialmente formulada por Krugman (1986). O primeiro objetivo deste trabalho foi testar o pricing-to-market realizado pelos exportadores brasileiros entre 1999 e 2012 utilizando dados para 26 setores industriais. À partir do modelo de Marston (1990), a sua estratégia de identificação adotada foi expandida para ser utilizada em dados em painel e considerar a possibilidade de cointegração entre as variáveis. Modelos de correção de erros em painel foram estimados utilizando diferentes técnicas de estimação, o efeito médio da taxa real de câmbio no longo prazo é de 0.673, ou seja, um aumento de 1% na taxa real de câmbio leva a um aumento de aproximadamente 0.07% nos preços relativos. No curto prazo, o efeito médio da taxa real de câmbio é de 0.233 nos preços relativos. Então há um efeito maior da taxa real de câmbio no longo prazo que no curto prazo. Após encontrar evidências de pricing-to-market nas exportações brasileiras, este estudo testou a assimetria do pricing-to-market através do modelo de painel com parâmetros limiares proposto por Hansen (1999). Foi estudado se a assimetria ou a volatilidade cambial possuem efeitos no nível de pricing-to-market realizado. As evidências encontradas mostram que a taxa real de câmbio possui efeitos assimétricos, há um aumento do pricing-to-market com a desvalorização cambial. / The segmentation of international markets allows the pricing-to-market, hypothesis initially defined by Krugman (1986). The first objective of this work is to test the pricing-to-market held by Brazilian exporters between 1999 and 2012 using data panel for 26 industrial sectors. Using the model proposed by Marston (1990), his identification strategy has been expanded from and consider the possibility of cointegration between the variables. Panel error correction models were estimated using differents estimation techniques, the average effect of the real exchange rate in the long run is 0.673, i.e. an increase of 1% in the real exchange rate leads to an increase of 0.07% in relative prices. In the short term, the average effect of the real exchange rate is 0.233 in relative prices. So there is a higher effect of real exchange rate in the long run than the in the short term. After finding evidence of the Brazilian pricing-to-market, this study tested the asymetric pricingto-market using the panel threshold model proposed by Hansen (1999). It was examined whether the exchange rate asymmetry or the volatility have effects on the level of pricing-tomarket. The evidences shows the real exchange rate has asymmetric effects, there is an increase of brazilian pricing-to-market associated with a depreciated exchange rate.

Submitted by Mariana Dornelles Vargas (marianadv) on 2015-03-19T15:37:37Z No. of bitstreams: 1 analise_importacao.pdf: 945712 bytes, checksum: 6101bf28275e0f55c9b783cb13f2a508 (MD5) / Made available in DSpace on 2015-03-19T15:37:37Z (GMT). No. of bitstreams: 1 analise_importacao.pdf: 945712 bytes, checksum: 6101bf28275e0f55c9b783cb13f2a508 (MD5) Previous issue date: 2011-03-30 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho procurou avaliar o comportamento da função de demanda brasileira por arroz pós-Mercosul e sua relação com a variação na renda, nos preços internos e externos, na indústria e política comercial brasileira. Para a análise, foi desenvolvido um modelo teórico, o qual fundamentou a especificação dos modelos econométricos para o arroz em casca e beneficiado. Considerou-se na investigação estatística dados históricos de janeiro de 1995 a junho de 2010, tendo como objetivo geral testar a adequação de modelos lineares e não-lineares que representem as relações de curto e longo prazo das variáveis de comércio exterior brasileiro do setor. Além disso, pretende-se datar a cronologia dos ciclos das importações de arroz e verificar a relação desses com as idiossincrasias da condução das políticas econômicas, bem como com eventos climáticos. As elasticidades encontradas apresentaram sinais coerentes com o modelo econômico definido em sua maioria. Os resultados obtidos permitiram interpretar a dinâmica do mercado importador de arroz no Brasil. Em geral, os impactos de longo prazo da renda e preço doméstico foram os principais determinantes das importações e ressalta-se o comportamento de bem inferior de ambos os tipos de arroz nas equações trimestrais. Já o preço de importação contribui menos que proporcionalmente, ao passo que o importador parece ajustar a quantidade importada do período com certo grau de defasagem. Já a indústria, tendo como base dados trimestrais, manteve uma relação contra-cíclica com as importações de ambos os tipos de arroz, embora não tenha se mostrado significativa para a maioria dos modelos. A dinâmica de correção do modelo a choques no longo prazo foi atenuada nas estimativas não-lineares mensais, enquanto permaneceu praticamente estável nas estimativas trimestrais. Ainda, conforme os resultados é possível afirmar que os ciclos de expansão das importações de arroz beneficiado durante o período foram, em média, mais longos que as retrações. Finalmente, pode-se entender que os ciclos de importação se mostraram fortemente relacionados a eventos climáticos adversos e à alterações da política comercial. / This study tried to investigate the behavior of Brazilian demand for post-Mercosur rice and its relation with variation in income, in domestic and foreign prices, in industry and in Brazil?s trade policy. For the analysis, a theoretical model was developed, which based the specification of econometric models for rough and milled rice. The statistical investigation considered historical data from January 1995 through June 2010, aiming mainly to test the adequacy of linear and nonlinear relations that represent short and long-term variables of the Brazilian foreign trade in the sector. Furthermore, there is the goal of setting the chronology of the cycles of rice imports and verifying their relationship with idiosyncrasies of the conduct of economic policies, as well as of weather events. The elasticities estimated showed signs consistent with the economic model set in their majority. The results achieved allowed the interpretation of the rice import market dynamics in Brazil. In general, long-term impacts from income and domestic prices were the main determinants of imports; it should be pointed out the much lower behavior of both types of rice in quarterly equations. The price of imports contributes less than proportionately, while the importer seems to adjust the quantity imported in the period with some lag. The industry, based on quarterly data, sustained its counter-cyclical relation with the imports of both types of rice, although it has been not proved significant for most models. The correction dynamic of the model to long-term shocks was eased in monthly non-linear equations, while it remained nearly stable in quarterly estimates. Besides, still according to results, it is possible to say that expansion cycles of imports of milled rice are on average longer than the contractions. Finally, one can understand that import cycles were strongly related to adverse climatic events, as well as to alterations in trade policy.

Submitted by Mariana Dornelles Vargas (marianadv) on 2015-06-15T14:27:47Z No. of bitstreams: 1 efeitos_mecanismos.pdf: 1238336 bytes, checksum: d005a9b54ec8b6cb1f09c6a122961c17 (MD5) / Made available in DSpace on 2015-06-15T14:27:47Z (GMT). No. of bitstreams: 1 efeitos_mecanismos.pdf: 1238336 bytes, checksum: d005a9b54ec8b6cb1f09c6a122961c17 (MD5) Previous issue date: 2012-01-12 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo desse estudo é investigar de que forma ocorrem os efeitos de transmissão de política monetária no Brasil e no Chile. Para esse fim, é utilizado um modelo econométrico VEC (vector error correction), no período do primeiro trimestre de 1995 até o último de 2010 para o modelo brasileiro de do primeiro trimestre de 2000 até o primeiro de 2011 no Chile. Inicialmente, a revisão teórica e empírica faz uma discussão acerca do tema. Subsequentemente, são analisados alguns fatos estilizados sobre as políticas monetárias do Brasil e do Chile e outras variáveis macroeconômicas. Os principais resultados encontrados por meio do modelo econométrico mostraram que a política monetária brasileira pode ser capaz de influenciar a produção industrial no longo prazo, e ocorre um trade-off entre elevação na atividade econômica e controle da inflação. Adicionalmente, a manutenção da taxa de juros num patamar alto pode implicar em queda da atividade econômica, elevação da dívida pública sobre o PIB e valorização cambial, que possui efeito de controlar a inflação, mas reduz a atividade industrial. Entretanto, a alta nos juros pode ser influenciada por aumentos da dívida pública e no risco. A taxa de câmbio mostrou-se como um canal relevante para a transmissão de política monetária, no entanto, sem efeitos no longo prazo. No Chile, a política monetária pareceu agir passivamente, com a produção industrial sendo o canal mais relevante para a desaceleração da inflação. A taxa de câmbio não demonstrou desempenhar um papel relevante na transmissão da política monetária. Por sua vez, um aumento na taxa de juros pareceu ter maior sensibilidade na queda na atividade industrial em relação à desaceleração da inflação, com efeito de longo prazo. A pouca influência dos riscos na taxa de juros pode indicar que o Banco Central chileno consegue manter essa variável num patamar baixo, otimizando sua atuação. / The aim of this study is to investigate how monetary policies are transmitted and their effects in Brazil and Chile. For this purpose, a VEC (vector error correction) model is applied to data running from the first quarter of 1995 to the fourth quarter of 2010 for Brazil and from the first quarter of 2000 to the first of 2011 in Chilean case. Initially, in the review, a theoretical and empirical discussion of the theme is performed. Subsequently, some stylized facts about the monetary policies of Brazil and Chile and other macroeconomic variables for these countries are analyzed. The main results found by the econometric model are that the Brazilian monetary policy may be able to influence economic activity in the long run, and that is a trade-off between increased industrial production and inflation control. Additionally, keeping interest rates at a high level can result in an economic activity downturn, a rising public debt to GDP ratio and an exchange rate appreciation, which has the effect of controlling inflation, but reduces industrial activity. However, the rise in interest rates may be influenced by increases in public debt and risk. The exchange rate showed up as a relevant channel for the transmission of monetary policy, although, not exhibiting long run effects. In Chile, monetary policy seemed to act passively, with industrial production being the most important channel for the deceleration of inflation. The exchange rate has not demonstrated an important role in monetary policy transmission. Furthermore, an increase in interest rates seemed to have greater sensitivity in the fall in industrial activity in relation to the deceleration of inflation, and a long run effect. The low influence of risks in the interest rate may indicate that the Chilean Central Bank can keep this variable in a low base, optimizing its performance.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-06-16T14:20:53Z No. of bitstreams: 1 Eduarda Martins Correa da Silveira.pdf: 825671 bytes, checksum: 02c3fcea0957cd9bb91507ffbd8c96be (MD5) / Made available in DSpace on 2015-06-16T14:20:53Z (GMT). No. of bitstreams: 1 Eduarda Martins Correa da Silveira.pdf: 825671 bytes, checksum: 02c3fcea0957cd9bb91507ffbd8c96be (MD5) Previous issue date: 2015-02-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo principal desta dissertação foi verificar se o balanço de pagamentos é uma limitação para o crescimento econômico brasileiro, no período que compreende os anos de 1995 até 2013, considerando o arcabouço teórico de Thirlwall (1979). Para o alcance desse objetivo, foram estimadas as funções demanda por importações e exportações através de dois modelos econométricos: vetorial de correção de erros (VAR/VEC) e modelo estrutural em formato de estado de espaço para o período 1995-2013. As funções demanda por exportações e importações também foram estimadas por meio do modelo estrutural em formato de estado de espaço para o período 2001-2013, com a intenção de verificar o impacto da elevação dos preços das commodities e o aumento na demanda por esses bens nos parâmetros calculados. Pela análise, para esse período, nota-se que o processo de commoditização da pauta de exportações brasileira aprofundou o problema da restrição externa brasileira. Na estimação da função demanda por exportações, utilizando o modelo VAR/VEC, foi incluída uma variável que representou o preço das commodities. Os resultados empíricos deste trabalho confirmam que o balanço de pagamentos é uma restrição ao crescimento econômico brasileiro, dado tanto pela razão entre as elasticidades-renda das exportações e importações, como também pela baixa sensibilidade das exportações ao câmbio real. Logo, o ajuste da balança comercial via alterações suaves da taxa de câmbio tem pouca eficácia para o caso brasileiro. Além disso, as exportações são mais sensíveis aos preços das commodities do que à taxa de câmbio real. / The main objective of the present dissertation was to verify if the balance of payments was a limitation to Brazilian economic growth, in the period of the years 1995 to 2013, considering the Thirwall's Law (1979). In order to achieve this goal, export and import demand functions were estimated by two econometric models: vector error correction (VAR/VEC) and structural state space model for the period of 1995-2013. The export and import demand functions were also estimated by the structural state space model for the period of 2001-2013, with the intention of verifying the impact of the commodities price increase and the increase in the demand for these goods in the estimated parameters. According to the analysis of this period, it has been noticed that commoditization process in the Brazilian exports agenda has increased the problem of Brazilian external constraint. In the estimation of the export demand function, using the VAR/VEC model, it was included a variable which represented commodities price. The empiric results of this paper confirm that the balance of payments is a constraint to the Brazilian economic growth, given the ratio between exports and imports income elasticities and, also, the exports low sensitivity to the real exchange. Thus, the adjustment of the balance of trade by soft alterations in the exchange rate have little efficiency for the Brazilian case. Furthermore, the exports are more sensitive to the commodities price than to the real exchange rate.