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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.
91

Design of Pipelined Analog-to-Digital Converter with SI Technique in 65 nm CMOS Technology

Rajendran, Dinesh Babu January 2011 (has links)
Analog-to-digital converter (ADC) plays an important role in mixed signal processingsystems. It serves as an interface between analog and digital signal processingsystems. In the last two decades, circuits implemented in current-modetechnique have drawn lots of interest for sensory systems and integrated circuits.Current-mode circuits have a few vital advantages such as low voltage operation,high speed and wide dynamic ranges. These circuits have wide applications in lowvoltage, high speed-mixed signal processing systems. In this thesis work, a 9-bitpipelined ADC with switch-current (SI) technique is designed and implemented in65 nm CMOS technology. The main focus of the thesis work is to implement thepipelined ADC in SI technique and to optimize the pipelined ADC for low power.The ADC has a stage resolution of 3 bits. The proposed architectures combine adifferential sample-and-hold amplifier, current comparator, binary-to-thermometerdecoder, a differential current-steering digital-to-analog converter, delay logic anddigital error correction block. The circuits are implemented at transistor level in 65nm CMOS technology. The static and dynamic performance metrics of pipelinedADC are evaluated. The simulations are carried out by Cadence Virtuoso SpectreCircuit Simulator 5.10. Matlab is used to determine the performance metrics ofADC.
92

Investor distraction during the Swedish summer and stock market under-reaction to companies’ earnings releases

Guscott, Alyssa, Bach, My January 2011 (has links)
This paper investigates whether greater investor distraction on the Swedish stock market during the summer months of June, July and August leads to a more pronounced post earnings announcement drift (PEAD) effect, during the ten year period between 2000 and 2009. PEAD is an anomaly whereby the information contained in earnings announcements is not immediately or completely incorporated into stock prices, in the cases where the announcement contains an ‘earnings surprise’. The methodology involves using the standardised unexpected earnings (SUE) metric to measure the level of ‘earnings surprise’ and a buy and hold abnormal returns (BHAR) trading strategy to measure return. The study tests and confirms the existence of greater investor distraction during summer months on the Swedish market. For a holding period of 12 months, a BHAR trading strategy generates a greater abnormal return for summer months (11.3%) compared with the abnormal return for non-summer months (10.5%). These results are also interesting in a broader context, as they confirm the existence of the PEAD effect, one of the strongest counter-arguments to the efficient markets hypothesis (EMH); the foundation of many financial models used for stock market valuation. This is because, according to the EMH, in an efficient market it should not be possible to generate abnormal returns based on available information. However, it may be noted that these results do not take into account transaction costs. This means that while it can be demonstrated that there is greater investor distraction during the Swedish summer, in order to implement a successful trading strategy based on this finding, further testing would be required. Therefore, based on the findings of this paper, a number of areas for future research have been identified.
93

Incertitude, renégociations et incitations dans les partenariats public privé

Athias, Laure 23 November 2007 (has links) (PDF)
L'objectif de cette thèse est de contribuer à une meilleure compréhension des Partenariats Public-Privé (PPPs). Ces accords entre une autorité publique et un opérateur privé sont considérés comme une "troisième voie" entre fourniture publique et privatisation des services publics. Cependant, les résultats que les PPPs ont produits dans le monde à ce jour sont mitigés. La littérature théorique sur ce sujet a souligné que les PPPs, comme tout contrat de long terme, se caractérisent par une forte incertitude et sont donc sujets à des adaptations ex post non contractuelles. Cette caractéristique a deux conséquences préjudiciables sur l'efficacité des PPPs: premièrement, lorsque des investissements spécifiques sont impliqués, les renégociations peuvent laisser place à d'éventuels comportements opportunistes, de l'autorité publique et de l'opérateur privé. Deuxièmement, les renégociations génèrent des inefficacités dans la mesure où les hold-ups conduisent à des décisions ex ante tordues. Dans ce contexte, les contributions de ma thèse sont les suivantes: premièrement, je montre empiriquement, en analysant le comportement à enchérir des participants aux enchères de contrats de concessions routières à péage, que incertitude et renégociations opportunistes sont bien caractéristiques des PPPs, jusque-là supposées par la littérature. Deuxièmement, je montre théoriquement et empiriquement que ces problèmes peuvent être pris en compte lors de l'arbitrage entre rigidité et flexibilité contractuelle. Troisièmement, je montre théoriquement que les contrats qui ne font pas supporter le risque de demande à l'opérateur privé, afin de remédier aux problèmes d'incertitude et de renégociations, introduisent des incitations tordues pour les autorités publiques à être attentives ex post aux préférences des consommateurs.
94

FILTERED-DYNAMIC-INVERSION CONTROL FOR FIXED-WING UNMANNED AERIAL SYSTEMS

Mullen, Jon 01 January 2014 (has links)
Instrumented umanned aerial vehicles represent a new way of measuring turbulence in the atmospheric boundary layer. However, autonomous measurements require control methods with disturbance-rejection and altitude command-following capabilities. Filtered dynamic inversion is a control method with desirable disturbance-rejection and command-following properties, and this controller requires limited model information. We implement filtered dynamic inversion as the pitch controller in an altitude-hold autopilot. We design and numerically simulate the continuous-time and discrete-time filtered-dynamic-inversion controllers with anti-windup on a nonlinear aircraft model. Finally, we present results from a flight experiment comparing the filtered-dynamic-inversion controller to a classical proportional-integral controller. The experimental results show that the filtered-dynamic-inversion controller performs better than a proportional-integral controller at certain values of the parameter.
95

The economic basis of syndicated lending

Wild, William January 2004 (has links)
This work undertakes the first comprehensive theoretical assessment of syndicated loans. It is shown that syndicated and bilateral (single lender) loans should be good substitutes in meeting a borrower's financing requirements, but that syndicated loans are more complex and impose additional risks to the parties in the way they are arranged. The existing explantions of loan syndication - that they are hybrids of private bank loans and public debt instruments, that syndication is a portfolio management tool, and that loans are syndicated where they are too large to be provided bilaterally - are unable to substantially explain both the nature of syndicated loans and practice in the loan markets. A rigorous new explanation is developed, which shows that syndication reduces the rate of lending costs, so that the return to the loan originator is greater, and the borrower's cost of financing is lower, where a loan is syndicated rather than provided bilaterally. This explanation is shown to hold in competitive loan markets and to be consistent with the observation that syndicated loans are generally larger than other loans. Incidental to this new explanation, new expressions of the return to a bank from providing a loan on a bilateral basis and from originating a syndicated loan are also developed. New algorithms are also developed for determining the distribution of the commitments from syndicate participants and thus the originator's final hold, the amount it must lend itself, where the loan is underwritten. This provides, for the first time, a rigorous basis for assessing the expected return, and the risk, for the originator of a given syndicated loan. Finally, empirical testing finds that a bank's observed lending history is significant to its decision to participate in a new syndicated loan but that predictions of participation, which are fundamental inputs into the final hold algorithms, based on this information have relatively little power. It follows that there is competitive advantage to loan originators that have access to other, private information on potential participants' lending intentions.
96

Economia das licitações, a contratação de obras e reformas em prédios públicos : o caso da UFRGS

Silva, Marcos José da January 2018 (has links)
Este estudo faz uma análise teórica e empírica dos processos de licitação e contratação de obras e reformas de prédios públicos em uma Universidade Pública Federal, utilizando a Teoria da Informação Assimétrica e dos Contratos. O período da pesquisa foi entre 2010 a 2013, na Universidade Federal do Rio Grande do Sul, sendo que foram analisados 127 processos licitatórios e contratos. As análises revelaram diversas ocorrências em licitações e nas contratações de obras e reformas. Na etapa licitatória, anterior à contratação (ex ante), a sessão para lances das licitações de obras e reformas, em alguns casos, estiveram desertas. Na contratação e execução de obras e reformas (ex post), foram constatados diversos pedidos de prorrogação de prazos e de reequilíbrio econômico financeiro, e na fiscalização das obras e reformas foram constatadas 31 ocorrências nos serviços finalizados pelas Empreiteiras. Os resultados também indicaram que, do total dos processos analisados no período de 2010 – 2013, cerca de 30% das obras e reformas ainda não foram finalizadas ou estão suspensas, o que demonstra deficiências na fiscalização e na gestão dos contratos. Além disso, o tempo médio entre a abertura do processo e a conclusão dos serviços gira em torno de três anos, sendo que grande parte deste tempo foi despendido com procedimentos internos da UFRGS. Tais fatos indicam problemas de seleção adversa e assimetria de informações, além do Hold up problem, em que o Principal é tomado como refém pelo Agente e do problema do Risco moral (Moral Hazard), em que o Agente passa a agir de modo não apropriado ou não aprovado pelo Principal, com a ocorrência dos custos de transação. / This study makes a theoretical and empirical analysis of the processes of bidding and contracting works and reforms of public buildings in a Federal Public University, using Asymmetric Information Theory and Contracts. The period analyzed was between 2010 and 2013, at the Federal University of Rio Grande do Sul, being that 127 bidding processes and contracts were analyzed. The analyses revealed several occurrences in tenders and hiring of work and restoration. In the bidding phase, prior to hiring (ex ante), the bidding session for work and renovations, in some cases, was deserted. There were several requests for deadline extension, and economic-financial adjustment in the work and restoration hiring and execution (ex post), while in the inspection of work and restoration it could be noticed 31 occurrences in services finalized by the contractors. The results also indicated that, of the total number of processes analyzed in the period 2010-2013, about 30% either have not been completed or are suspended, which shows deficiencies in the supervision and management of the contracts. In addition, the average time between the opening of the process and the conclusion of services is about three years, and much of this time was spent with internal procedures of UFRGS. These facts indicate problems of adverse selection and information asymmetry , in addition to the "Hold up problem", in which the Principal is taken hostage by the Agent besides the problem of Moral Hazard, when the Agent begins to act inappropriately or in a way which is disapproved by the Principal, together with the incidence of transaction costs.
97

Etude des interactions fatigue-fluage-environnement lors de la propagation de fissure dans l'Inconel 718 DA / Fatigue-creep-environment effect on the crack growth behaviour under hold-time conditions in DA Inconel 718

Fessler, Emmanuel 15 December 2017 (has links)
L’Inconel 718 est un superalliage base nickel largement utilisé par les motoristes tels Safran Aircraft Engines pour l’élaboration des disques de turbine. Après forgeage des disques, un traitement de vieillissement appelé « Direct Aged » est appliqué. En service, le régime de croisière représente un temps de maintien sous chargement constant pour les disques. Bien que pas complètement compris, il est largement admis qu’un temps de maintien dans un cycle de fatigue a un effet néfaste sur le comportement en fissuration de l’Inconel 718 ainsi que d’autres superalliages. Cette étude porte donc sur la fissuration en fatigue-fluage dans l’Inconel 718 DA à 550°C et 650°C. Des essais sont menés pour des temps de maintien allant jusqu’à 1h. Des développements de la méthode de suivi de fissure par mesure de potentiel (DCPD) ont permis d’identifier la décharge-recharge (contribution de fatigue) d’un cycle de fatigue-fluage comme la partie la plus néfaste du cycle. L’application d’un temps de maintien amplifie cette contribution. Le temps de maintien induit également des fronts de fissure extrêmement courbes et tortueux, contrairement à de la fatigue pure. Une stratégie numérique a été développée, couplant la simulation 3D de la propagation et la méthode dite DCPD, permettant de réaliser des « essais numériques ». La propagation de fronts courbes et tortueux est simulée. Il a été démontré que le comportement en propagation est directement lié à la forme du front de fissure et son évolution. Des essais complexes ont été menés, sous vide, ou impliquant des surcharges. Lorsque l’effet du temps de maintien est annihilé, les morphologies complexes des fronts disparaissent. Elles sont alors associées à une inhibition locale de l’effet endommageant de l’environnement due à la plasticité et aux vitesses de déformation locales. Tous les essais présentés sont analysés en considérant l’effet de la vitesse de déformation locale qui influe largement le comportement en fissuration de l’Inconel 718. / Inconel 718 is a nickel-based superalloy widely used by aeroengines manufacturers like Safran Aircraft Engine to manufacture turbine disks. After forging, disks are given an ageing treatment called “Direct Aged”. In service, during cruise, these critical components handle hold-time periods at constant loading. It is well known, although not fully understood, that hold-time increases crack growth rates (CGR) in Inconel 718 as well as others superalloys. Therefore, this study focuses on crack propagation under hold-time conditions in DA Inconel 718, at 550°C and 650°C. Experiments were carried out for different hold-times, up to 1h. Developments on the crack monitoring technique (DCPD) led to the conclusion that the most damaging part of the cycle is load-reversal (fatigue contribution). This contribution is enhanced by the hold-time period. Holdtime leads to dramatically curved and tortuous crack front, contrary to pure fatigue cycles. A numerical framework was developed, combining crack growth and DCPD simulations, so that “numerical tests” can be carried out. Using this method, crack growth simulations were performed from curved and tortuous, experimentally reproduced, crack front. It was concluded that increased crack CGR under hold-time conditions are closely related to the crack front morphology and its evolution during propagation. More complex tests, with overloads or under vacuum, were carried out. When the hold-time effect is inhibited, complex morphologies vanish. Such morphologies were associated to local inhibition of the environmental damaging effect due to local high plastic strain and strain rates. The large variety of experiments, presented in this study, was then successfully analyzed considering the effect of local strain rates which greatly influence the crack growth behavior of Inconel 718.
98

Erfarenheter från insatserna i Somalia under 1990-talet : kopplat till utvecklingen av den amerikanska doktrinen FM3-24

Carlbaum, Gustaf January 2012 (has links)
Den amerikanska doktrinen FM3-24 beskriver hur en operation inom COIN-konceptet kan genomföras och hur befälhavaren kan använda doktrinen som stöd i genomförande och planering av operationer.  Doktrinen är utvecklad med stöd av de lärdomar som amerikanska trupper dragit i 2000-talets konflikter i Irak och Afghanistan, och doktrinen används idag som stöd i de pågående insatserna. Under 1990-talets konflikt i Somalia fanns inte denna doktrin.  Syftet med uppsatsen är att undersöka om det kan spåras lärdomar redan från 1990-talets Somalia till utformandet av den nu utvecklade amerikanska doktrinen FM3-24.  Resultatet visar att likheter finns i hur operationer enligt FM3-24 skall genomföras, dock är olikheterna de som är mest tydliga. Många av de steg som beskrivs i doktrinen har under insatsen avvikit helt eller vartefter insatsen fortskred. En orsak till det kan vara att amerikanska trupper under början av 1990-talet inte hade samma erfarenhet av COIN-insatser som de hade när doktrinen under 2000-talet utvecklades. I slutet av studien presenteras tänkta ”lessons learned” som kan vara bidragande till doktrinens utformning.
99

3D analýza okamžitého vlivu vložek do bot s posturální pelotou dle Raševa a s proceptory PodoAktiv na posturu. / 3D analysis of immediate effect on posture of shore with postural insoles based on Rašev and with proceptor insoles PodoAktiv

Koukalová, Martina January 2018 (has links)
Title: 3D analysis of immediate effect on posture of shoe with postural insoles based on Rašev and with proceptor insoles PodoAktiv® Objective: The aim of this study is to evaluate the immediate effect of shoe insoles with postural pelote by Rašev and shoe insoles with proceptors PodoAktiv® on the postural hold with main focus at the pelvis and shoulder. Methodology: In this thesis we examined 9 participants who agreed joining the study. To messure postural hold body segments which we have chosen, we have used the Balance® 4D device. The selected body segments were marked by white spheric stickers. To compare postural hold of selected body segments we examined the participants in altogether 4 situations. Barefoot stand, stand in shoes without insoles, stand in shoes with custom-made postural insoles based on Rašev and stand in shoes with custom-made insoles PodoAktiv® . Results: In this study we confirmed that postural insoles based on Rašev have immediate effect on the hold of pelvis and shoulders. The insoles PodoAktiv® don't show such an effect on the hold of those segments we have tested. The hypothesis H1 and H2 have been confirmed, hypothesis H3 and H4 have been rejected. There was not found any trend which would describe the immediate reaction of the participants (postural hold with main...
100

Economia das licitações, a contratação de obras e reformas em prédios públicos : o caso da UFRGS

Silva, Marcos José da January 2018 (has links)
Este estudo faz uma análise teórica e empírica dos processos de licitação e contratação de obras e reformas de prédios públicos em uma Universidade Pública Federal, utilizando a Teoria da Informação Assimétrica e dos Contratos. O período da pesquisa foi entre 2010 a 2013, na Universidade Federal do Rio Grande do Sul, sendo que foram analisados 127 processos licitatórios e contratos. As análises revelaram diversas ocorrências em licitações e nas contratações de obras e reformas. Na etapa licitatória, anterior à contratação (ex ante), a sessão para lances das licitações de obras e reformas, em alguns casos, estiveram desertas. Na contratação e execução de obras e reformas (ex post), foram constatados diversos pedidos de prorrogação de prazos e de reequilíbrio econômico financeiro, e na fiscalização das obras e reformas foram constatadas 31 ocorrências nos serviços finalizados pelas Empreiteiras. Os resultados também indicaram que, do total dos processos analisados no período de 2010 – 2013, cerca de 30% das obras e reformas ainda não foram finalizadas ou estão suspensas, o que demonstra deficiências na fiscalização e na gestão dos contratos. Além disso, o tempo médio entre a abertura do processo e a conclusão dos serviços gira em torno de três anos, sendo que grande parte deste tempo foi despendido com procedimentos internos da UFRGS. Tais fatos indicam problemas de seleção adversa e assimetria de informações, além do Hold up problem, em que o Principal é tomado como refém pelo Agente e do problema do Risco moral (Moral Hazard), em que o Agente passa a agir de modo não apropriado ou não aprovado pelo Principal, com a ocorrência dos custos de transação. / This study makes a theoretical and empirical analysis of the processes of bidding and contracting works and reforms of public buildings in a Federal Public University, using Asymmetric Information Theory and Contracts. The period analyzed was between 2010 and 2013, at the Federal University of Rio Grande do Sul, being that 127 bidding processes and contracts were analyzed. The analyses revealed several occurrences in tenders and hiring of work and restoration. In the bidding phase, prior to hiring (ex ante), the bidding session for work and renovations, in some cases, was deserted. There were several requests for deadline extension, and economic-financial adjustment in the work and restoration hiring and execution (ex post), while in the inspection of work and restoration it could be noticed 31 occurrences in services finalized by the contractors. The results also indicated that, of the total number of processes analyzed in the period 2010-2013, about 30% either have not been completed or are suspended, which shows deficiencies in the supervision and management of the contracts. In addition, the average time between the opening of the process and the conclusion of services is about three years, and much of this time was spent with internal procedures of UFRGS. These facts indicate problems of adverse selection and information asymmetry , in addition to the "Hold up problem", in which the Principal is taken hostage by the Agent besides the problem of Moral Hazard, when the Agent begins to act inappropriately or in a way which is disapproved by the Principal, together with the incidence of transaction costs.

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