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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Alterações da solução do solo e resposta do arroz irrigado ao manejo da irrigação e da adubação nitrogenada / Soil solution changes and rice crop response as affected by irrigation and nitrogen management

Borin, José Bernardo Moraes January 2014 (has links)
Extensas áreas de produção de arroz irrigado podem ser afetadas pela escassez de água durante o ciclo da cultura, dependendo das precipitações pluviais e do gerenciamento dos mananciais hídricos pelo produtor. A irrigação intermitente é uma alternativa para a otimização do uso da água pela lavoura. Entretanto, esse manejo altera a dinâmica e disponibilidade de nutrientes na solução do solo, podendo afetar também a cultura. O objetivo deste trabalho foi avaliar a eletroquímica e a dinâmica de nutrientes na solução do solo, assim como a resposta do arroz ao parcelamento da adubação nitrogenada, em diferentes sistemas de irrigação. O experimento foi conduzido no campo, no ano agrícola de 2012/13, em um Gleissolo, na Estação Experimental do Arroz (EEA) do Instituto Rio Grandense do Arroz (IRGA), em Cachoeirinha/RS. Os tratamentos testados foram: irrigação contínua e irrigação intermitente com uma e duas supressões no estágio vegetativo. Nas subparcelas, o manejo de aplicação de N constou de 0 kg ha-1 e 150 kg ha-1 em duas e três vezes. A eletroquímica é afetada pelos sistemas de irrigação e influenciam a dinâmica e disponibilidade dos nutrientes na solução do solo. Na irrigação contínua a disponibilidade dos nutrientes é maior em relação às irrigações intermitentes. Embora a biomassa e o acúmulo do nitrogênio sejam afetados, a produtividade não diferenciou entre os sistemas de irrigação e o manejo de adubação nitrogenada. A intermitência pode ser utilizada como uma ferramenta para melhorar a eficiência de utilização do nitrogênio pela cultura do arroz irrigado. / Large areas of irrigated rice production can be affected by water scarcity during the crop cycle, depending on rainfall and management of water sources by farmer. Intermitent irrigation is an alternative to the optimization of water use by the crop. However, this management modifies the nutrient dynamics and availability in the soil solution and may also affect the crop. The objective of this study was to evaluate the electrochemical and nutrient dynamics in the soil solution, as well as the response of rice to the split of nitrogen fertilization under different irrigation systems. The experiment was conducted under field conditions in the 2012/13 agricultural season, on an Albaqualf soil in the Rice Experiment Station of Instituto Rio Grandense do Arroz (IRGA), in Cachoeirinha/RS. The treatments tested were: continuous flooding and intermittent irrigation with one and two dry cycles in the vegetative stage. Subplots consisted of nitrogen application of 0 kg ha-1 and 150 kg ha-1 in two and three splits. The soil solution electrochemistry is affected by irrigation systems and influence the nutrients dynamics and availability. In continuous flooding, nutrients availability is greater compared to intermittent irrigation. Although biomass and nitrogen accumulation are affected, grain yield did not differ between the irrigation systems and nitrogen fertilization management. The intermittent irrigation can be used as a tool to improve the nitrogen use efficiency by irrigated rice.
12

Intégration et supervision des liens Fronthaul dans les réseaux 5G / Fronthaul integration and monitoring in 5G networks

Tayq, Zakaria 12 December 2017 (has links)
Le Cloud RAN a été préconisé pour la 5G. Cependant, sa mise en place rencontre des difficultés notamment sur l'intégration du fronthaul, ce dernier généralement basé sur l’interface CPRI représente le segment situé entre la Digital Unit et la Radio Unit. Vu les contraintes de débit, de latence et de gigue sur cette interface, le multiplexage en longueur est la solution adéquate pour son transport. En revanche, les technologies radio recommandées pour la 5G augmenteront considérablement les débits CPRI, ce qui rend l’utilisation du WDM bas coût très difficile. Cette thèse traite quatre sujets principaux : L'introduction d'un canal de contrôle dans le CPRI permettrait la supervision de l'infrastructure WDM et l'accordabilité en longueurs d'onde des transceivers. L’impact de l’intégration de ce canal de contrôle dans le fronthaul est étudié dans le chapitre II. La radio analogique sur fibre peut améliorer de manière significative l'efficacité spectrale du fronthaul, permettant potentiellement le transport des interfaces 5G. Une étude approfondie sur le gain réel apporté par cette solution est rapportée dans le chapitre III. La compression du CPRI basée sur la quantification uniforme et non uniforme est également une solution pour améliorer l'efficacité spectrale du CPRI. Le chapitre IV démontre expérimentalement les taux de compression réalisables. Enfin, les nouveaux splits fonctionnels sont considérés comme une solution prometteuse pour la 5G. Deux nouvelles interfaces ont été identifiées pour les splits couche haute et couche basse. Une étude théorique et expérimentale de ces nouvelles interfaces est présentée dans le chapitre V. / Cloud Radio Access Network (RAN) was identified as a key enabler for 5G. Its deployment is however meeting multiple challenges notably in the fronthaul integration, the latter being the segment located between the Digital Unit and the Radio Unit generally based on CPRI. Giving its bit-rate, latency and jitter constrains, Wavelength Division Multiplexing (WDM) is the most adequate solution for its transport. However, the radio technologies recommended for 5G will drastically increase the CPRI bit-rate making its transport very challenging with low-cost WDM. This thesis deals with four main topics : The introduction of a control channel in the CPRI enables offering the WDM infrastructure monitoring and the wavelength tunability in the transceivers. The study of this control channel integration in the fronthaul link is reported in the second chapter as well as an investigation on the wireless transmission of CPRI. The use of Analog Radio over Fiber (A-RoF) can significantly improve the fronthaul spectral efficiency compared to CPRI-based fronthaul enabling, potentially, the transport of 5G interfaces. A thorough investigation on the actual gain brought by this solution is stated in the third chapter. CPRI compression based on uniform and non-uniform quantization is also a solution to enhance the CPRI spectral efficiency. The fourth chapter describes this solution and experimentally shows the achievable compression rates. Finally, establishing a new functional split in the radio equipment was considered as a promising solution for 5G. Two new interfaces have been identified for high and low layer functional splits. A theoretical and experimental study of these new interfaces is reported in the fifth chapter.
13

The Emergence, Maintenance and Defeat of Dominant Party Authoritarian Regimes (DPARs)

Ong, Kian M. January 2010 (has links)
<p>This thesis is an investigation into the causes behind the emergence, maintenance and defeat of dominant authoritarian party regimes (DPARs). The emergence of these regimes during certain critical junctures in a country's history is attributed to the ability of charismatic leaders to co-opt political elites using electoral instruments and incentives under the banner of a single party. The presence of institutional mechanisms that can smooth the leadership transition process, provide rewards for elites to remain in the dominant party and increase the costs of elite defections are important explanatory factors in DPAR maintenance. DPARs also employ different strategies to co-opt and divide the opposition in order to reassert their political dominance. Intra regime splits are a necessary but not sufficient condition to weaken a DPAR. Institutional reform which further weakens a DPAR and increases the probability of future elite splits is introduced when the opposition can play a veto card. The mutually reinforcing effects of elite splits and institutional reform explain the downfall of DPARs in Mexico, Taiwan, Senegal and Paraguay. The DPAR in Malaysia is at a critical juncture whereby an opposition veto which can possibly lead to institutional reform currently hangs in balance.</p> / Dissertation
14

Modelagem de equações estruturais aplicada à reação a splits : integrando as hipóteses de liquidez, sinalização e nível ótimo de preços

Vieira, Kelmara Mendes January 2006 (has links)
Dentre as decisões adotadas pelos gestores quanto à política acionária em suas empresas, está a realização splits. Como a sua realização não altera a posição relativa dos investidores e não interfere nas políticas de investimento, de financiamento e de distribuição de resultados, espera-se, a luz da teoria financeira, que os splits sejam apenas eventos cosméticos. Entretanto, grande parte das pesquisas empíricas desenvolvidas ao longo dos últimos anos demonstra que o mercado reage positivamente ao splits. As possíveis explicações para este comportamento são ainda inconclusivas. Dentre as diversas hipóteses levantadas pela literatura três se destacam: sinalização, liquidez e nível ótimo de preços. Este trabalho tem como objetivo principal o desenvolvimento de um modelo capaz de considerar, simultaneamente, o papel destas hipóteses na explicação da reação dos investidores aos splits. Para avaliar a influência de cada uma das hipóteses e das suas inter-relações utiliza-se um modelo híbrido de equações estruturais. No modelo de mensuração, foram definidos quatro construtos: negociação, spread, tamanho e preço. O modelo estrutural define as relações existentes a partir da proposição de 22 hipóteses. Para a avaliação do modelo utilizou-se uma amostra de 321 splits realizados no mercado brasileiro entre 1990 e 2004. Os resultados da análise fatorial confirmatória apontaram para a validade e coerência dos quatro construtos, validando o modelo de mensuração. Após a eliminação das hipóteses não significativas e da inserção de algumas correlações entre os erros das variáveis, o modelo estrutural confirmou 12 das hipóteses levantadas originalmente e apresentou índices de ajuste adequados. De maneira geral, os resultados apontam para a pequena influência da assimetria informacional, dentre eles, o fato do tipo de split (bonificações ou desdobramentos) e do split fator não influenciarem a reação e a não significância das hipóteses que envolvem a maioria das variáveis relacionadas à assimetria. Quanto à decisão de realizar os splits, observou-se que o gestor leva em consideração principalmente a volatilidade e o preço para a escolha do split fator. / Among the decisions that managers make concerning stock policies in their companies, one can find the splits. As splits do not effect changes in the relative position of investors nor influences the policies for investment, financing and distribution of results, it is expected that, according to financial theory, splits play a cosmetic role and nothing else. Nonetheless, a great deal of current empirical research shows that the market reacts positively to splits. Possible explanations for such a behavior are yet inconclusive. Among the several hypotheses that were raised so far in the literature, three can be given special attention: signaling, liquidity, and optimal price level. The preset work develops a model able to take simultaneously the role of these hypotheses to explain the reaction of investors to the splits. In order to assess the influence of each hypothesis and interrelationships, a hybrid model of structural equations is deployed. Four constructs were defined in the measurement model: trading activity, spread, size, and price. The structural model defines extant relations from the proposition of 22 hypotheses. A sample of 321 splits performed in the Brazilian market between 1990 and 2004 was used for assessing the model. Confirmatory factor analysis revealed the validity and coherence of the four constructs, thus enabling one to claimabout the validity of the measurement model. After eliminating non-significant hypotheses and adding some correlations for the errors in variables, the structural model confirmed 12 original hypotheses and exhibited adequate fit indexes. Broadly, findings suggest that there is little influence from the informational asymmetry, among which the facts that the type of split (stock dividends or stock splits) and the split factor do not influence the reaction and the non-significance of the hypotheses that comprise most variables related to asymmetry. In what comes to deciding to do splits, it was clear that the manager mainly takes into account the volatility and the price for choosing the split factor.
15

Modelagem de equações estruturais aplicada à reação a splits : integrando as hipóteses de liquidez, sinalização e nível ótimo de preços

Vieira, Kelmara Mendes January 2006 (has links)
Dentre as decisões adotadas pelos gestores quanto à política acionária em suas empresas, está a realização splits. Como a sua realização não altera a posição relativa dos investidores e não interfere nas políticas de investimento, de financiamento e de distribuição de resultados, espera-se, a luz da teoria financeira, que os splits sejam apenas eventos cosméticos. Entretanto, grande parte das pesquisas empíricas desenvolvidas ao longo dos últimos anos demonstra que o mercado reage positivamente ao splits. As possíveis explicações para este comportamento são ainda inconclusivas. Dentre as diversas hipóteses levantadas pela literatura três se destacam: sinalização, liquidez e nível ótimo de preços. Este trabalho tem como objetivo principal o desenvolvimento de um modelo capaz de considerar, simultaneamente, o papel destas hipóteses na explicação da reação dos investidores aos splits. Para avaliar a influência de cada uma das hipóteses e das suas inter-relações utiliza-se um modelo híbrido de equações estruturais. No modelo de mensuração, foram definidos quatro construtos: negociação, spread, tamanho e preço. O modelo estrutural define as relações existentes a partir da proposição de 22 hipóteses. Para a avaliação do modelo utilizou-se uma amostra de 321 splits realizados no mercado brasileiro entre 1990 e 2004. Os resultados da análise fatorial confirmatória apontaram para a validade e coerência dos quatro construtos, validando o modelo de mensuração. Após a eliminação das hipóteses não significativas e da inserção de algumas correlações entre os erros das variáveis, o modelo estrutural confirmou 12 das hipóteses levantadas originalmente e apresentou índices de ajuste adequados. De maneira geral, os resultados apontam para a pequena influência da assimetria informacional, dentre eles, o fato do tipo de split (bonificações ou desdobramentos) e do split fator não influenciarem a reação e a não significância das hipóteses que envolvem a maioria das variáveis relacionadas à assimetria. Quanto à decisão de realizar os splits, observou-se que o gestor leva em consideração principalmente a volatilidade e o preço para a escolha do split fator. / Among the decisions that managers make concerning stock policies in their companies, one can find the splits. As splits do not effect changes in the relative position of investors nor influences the policies for investment, financing and distribution of results, it is expected that, according to financial theory, splits play a cosmetic role and nothing else. Nonetheless, a great deal of current empirical research shows that the market reacts positively to splits. Possible explanations for such a behavior are yet inconclusive. Among the several hypotheses that were raised so far in the literature, three can be given special attention: signaling, liquidity, and optimal price level. The preset work develops a model able to take simultaneously the role of these hypotheses to explain the reaction of investors to the splits. In order to assess the influence of each hypothesis and interrelationships, a hybrid model of structural equations is deployed. Four constructs were defined in the measurement model: trading activity, spread, size, and price. The structural model defines extant relations from the proposition of 22 hypotheses. A sample of 321 splits performed in the Brazilian market between 1990 and 2004 was used for assessing the model. Confirmatory factor analysis revealed the validity and coherence of the four constructs, thus enabling one to claimabout the validity of the measurement model. After eliminating non-significant hypotheses and adding some correlations for the errors in variables, the structural model confirmed 12 original hypotheses and exhibited adequate fit indexes. Broadly, findings suggest that there is little influence from the informational asymmetry, among which the facts that the type of split (stock dividends or stock splits) and the split factor do not influence the reaction and the non-significance of the hypotheses that comprise most variables related to asymmetry. In what comes to deciding to do splits, it was clear that the manager mainly takes into account the volatility and the price for choosing the split factor.
16

Modelagem de equações estruturais aplicada à reação a splits : integrando as hipóteses de liquidez, sinalização e nível ótimo de preços

Vieira, Kelmara Mendes January 2006 (has links)
Dentre as decisões adotadas pelos gestores quanto à política acionária em suas empresas, está a realização splits. Como a sua realização não altera a posição relativa dos investidores e não interfere nas políticas de investimento, de financiamento e de distribuição de resultados, espera-se, a luz da teoria financeira, que os splits sejam apenas eventos cosméticos. Entretanto, grande parte das pesquisas empíricas desenvolvidas ao longo dos últimos anos demonstra que o mercado reage positivamente ao splits. As possíveis explicações para este comportamento são ainda inconclusivas. Dentre as diversas hipóteses levantadas pela literatura três se destacam: sinalização, liquidez e nível ótimo de preços. Este trabalho tem como objetivo principal o desenvolvimento de um modelo capaz de considerar, simultaneamente, o papel destas hipóteses na explicação da reação dos investidores aos splits. Para avaliar a influência de cada uma das hipóteses e das suas inter-relações utiliza-se um modelo híbrido de equações estruturais. No modelo de mensuração, foram definidos quatro construtos: negociação, spread, tamanho e preço. O modelo estrutural define as relações existentes a partir da proposição de 22 hipóteses. Para a avaliação do modelo utilizou-se uma amostra de 321 splits realizados no mercado brasileiro entre 1990 e 2004. Os resultados da análise fatorial confirmatória apontaram para a validade e coerência dos quatro construtos, validando o modelo de mensuração. Após a eliminação das hipóteses não significativas e da inserção de algumas correlações entre os erros das variáveis, o modelo estrutural confirmou 12 das hipóteses levantadas originalmente e apresentou índices de ajuste adequados. De maneira geral, os resultados apontam para a pequena influência da assimetria informacional, dentre eles, o fato do tipo de split (bonificações ou desdobramentos) e do split fator não influenciarem a reação e a não significância das hipóteses que envolvem a maioria das variáveis relacionadas à assimetria. Quanto à decisão de realizar os splits, observou-se que o gestor leva em consideração principalmente a volatilidade e o preço para a escolha do split fator. / Among the decisions that managers make concerning stock policies in their companies, one can find the splits. As splits do not effect changes in the relative position of investors nor influences the policies for investment, financing and distribution of results, it is expected that, according to financial theory, splits play a cosmetic role and nothing else. Nonetheless, a great deal of current empirical research shows that the market reacts positively to splits. Possible explanations for such a behavior are yet inconclusive. Among the several hypotheses that were raised so far in the literature, three can be given special attention: signaling, liquidity, and optimal price level. The preset work develops a model able to take simultaneously the role of these hypotheses to explain the reaction of investors to the splits. In order to assess the influence of each hypothesis and interrelationships, a hybrid model of structural equations is deployed. Four constructs were defined in the measurement model: trading activity, spread, size, and price. The structural model defines extant relations from the proposition of 22 hypotheses. A sample of 321 splits performed in the Brazilian market between 1990 and 2004 was used for assessing the model. Confirmatory factor analysis revealed the validity and coherence of the four constructs, thus enabling one to claimabout the validity of the measurement model. After eliminating non-significant hypotheses and adding some correlations for the errors in variables, the structural model confirmed 12 original hypotheses and exhibited adequate fit indexes. Broadly, findings suggest that there is little influence from the informational asymmetry, among which the facts that the type of split (stock dividends or stock splits) and the split factor do not influence the reaction and the non-significance of the hypotheses that comprise most variables related to asymmetry. In what comes to deciding to do splits, it was clear that the manager mainly takes into account the volatility and the price for choosing the split factor.
17

Essays on Stock Return Predictability: Novel Measures Based on Technology Spillover and Firm's Public Announcement

Bai, Qing 12 September 2014 (has links)
No description available.
18

Interplay between capacity and energy consumption in C-RAN transport network design

Wang, Huajun January 2016 (has links)
Current mobile network architecture is facing a big challenge as the traffic demands have been increasing dramatically these years. Explosive mobile data demands are driving a significant growth in energy consumption in mobile networks, as well as the cost and carbon footprints [1]. In 2010, China Mobile Research Institute proposed Cloud Radio Access Network (C-RAN) [2], which has been regarded as one of the most promising architecture to solve the challenge of operators. In C-RAN, the baseband units (BBU) are decoupled from the remote radio units (RRH) and centralized in one or more locations. The feasibility of combination of implementing the very tight radio coordination schemes and sharing baseband processing and cooling system resources proves to be the two main advantages of C-RAN compared to traditional RAN. More importantly, mobile operators can quickly deploy RRHs to expand and make upgrades to their networks. Therefore, the C-RAN has been advocated by both operators and equipment vendors as a means to achieve the significant performance gains required for 5G [3]. However, one of the biggest barriers has shown up in the deployment of C-RAN as the novel architecture imposes very high capacity requirement on the transport network between the RRHs and BBUs, which is been called fronthaul network. With the implementation of 5G wireless system using advanced multi-antenna transmission (MIMO), the capacity requirement would go further up, as well as the power consumption. One solution has been proposed to solve the problem is to have the baseband functions divided, partially staying with RRHs and other functions would be centralized in BBU pool. Different splitting solutions has been proposed in [4] [5] and [6]. In this thesis work, we choose four different splitting solutions to build four CRAN architecture models. Under one specific case scenario with the fixed number of LTE base stations, we calculate the transport capacity requirement for fronthaul and adopt three different fronthaul technology. The power consumption is calculated by adding up the power utilized by RRHs, fronthaul network and baseband processing. By comparing the numerical results, split 1 and 2 shows the best results while split 2 is more practical for dense cell area, since split 1 requires large fronthaul capacity. The fronthaul transport technology can be decided according to different density of base stations. TWDM-PON shows better energy performance as fronthaul network when the capacity requirement is high, compared to EPON. However, for larger number of BSs, mm-Wave fronthaul is a better solution in terms of energy efficiency, fiber saving and flexibility.
19

Stock Splits And The Impact On Abnormal Return : A Quantitative Research on Nasdaq Stockholm

Fausti, Giovanni, Sandelin, Gustaf, Bratt, Adam January 2021 (has links)
Throughout history stock splits have only been seen as a cosmetic change on how a firm express its market value of equity. This study investigates if abnormal return occurs in connection with stock split announcements on Nasdaq Stockholm and how the variations may be explained by selected factors. An event study is performed on 83 stock splits during the time period 2010-2020 to establish if abnormal return is present. With a multivariate linear regression, split quota, firm size and trading volume are the selected factors which may explain the variations in abnormal return. The results from the event study establish abnormal return one day prior to the announcement and the event day itself. Further, the regression confirms at a statistically significant level the negative relationship between firm size and abnormal return. For trading volume, the regression finds no statistically significant result and thereby it does not explain the variations in abnormal return. As for split quota, no conclusion can be drawn whether it affects abnormal return or not. The study concludes the occurrence of abnormal return in connection with stock split announcements on Nasdaq Stockholm and firm size as one of the factors explaining the variations.
20

'The affirmation of Behan?' : an understanding of the politicisation process of the Provisional Irish Republican Movement through an organisational analysis of splits from 1969 to 1997

Morrison, John F. January 2010 (has links)
One of the foremost reasons for the success of the Northern Irish Peace Process has been the ability of the national leadership of the Provisional Republican Movement to bring the majority of their membership away from the armed campaign and towards the acceptance of peaceful politics. This dissertation analyses how they were able to achieve this. This is carried out by considering the processes of the four major splits in modern day Irish republicanism from 1969 to 1997. Each split was analysed so as to derive why the split took place and why one side was more successful than the other in the aftermath. The cases were used to test a stage-based process model of split designed by the author. The data from thirty-eight semi-structured interviews were analysed using Interpretative Phenomenological Analysis (IPA). This analysis treated the three Provisional splits as three micro-processes within the macro-process of Provisional Republican involvement in the ‘Troubles', as it did the two Official splits with respect to the Official macro-process of involvement. The results of the analysis showed that the success of the later Provisional leadership was significantly tied to their method of changing strategies, tactics and policies one step at a time rather than by attempting to implement a variety of substantial changes within a short space of time as the leadership of the 1960s endeavoured to. This research outlines how the acceptance of peaceful politics for a terrorist organisation is a gradual stage-based process and that in order to be successful the significant changes must be implemented in a patient manner.

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