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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

Does real-time reporting deter strategic disclosures by management?

Tian, Xiaoli 01 July 2012 (has links)
Over the last decade, the SEC has taken a number of steps to move towards a real-time reporting regime in an effort to deter strategic accumulation of news disclosures by management. However, evidence from theoretical literature suggests managers are still able to engage in strategic bunching of within-firm disclosures under a real-time reporting regime if managers have control over the timing of news-triggering events. To test whether real-time reporting deters strategic disclosures I examine managers' disclosure behavior for both regular poison pill adoptions and in-play pill adoptions because managers can time the regular poison pill adoptions but have limited ability to do so for in-play pill adoptions. My results indicate real-time reporting does not (does) deter disclosure bunching for regular poison pills (in-play pills). To the extent that disclosure bunching occurs for in-play pills under the real-time reporting regime, my findings suggest managers are more likely to time the disclosure of other news to achieve disclosure bunching. Disclosure bunching dampens the negative pricing impact of poison pill adoption disclosures and continues to do so under the real-time reporting regime.
12

Weather effect considerations in reliability evaluation of electrical transmission and distribution systems

Acharya, Janak Raj 02 September 2005
<p>The weather environment has a significant impact on the reliability of a power system due to its effect on the system failure mechanisms of overhead circuits and on the operational ability of an electric power utility. The physical stresses created by weather increase the failure rates of transmission or distribution lines operating in adverse weather conditions, resulting in increased coincident failures of multiple circuits. Exceptionally severe weather can cause immense system damages and significantly impact the reliability performance. Recognition of the pertinent weather impacts clearly indicates the need to develop appropriate models and techniques that incorporate variable weather conditions for realistic estimation of reliability indices.</p> <p>This thesis illustrates a series of multi-state weather models that can be utilized for predictive reliability assessment incorporating adverse and extremely adverse weather conditions. The studies described in this thesis are mainly focused on the analyses using the three state weather model. A series of multi-state weather models are developed and utilized to assess reliability performance of parallel redundant configurations. The application of weather modeling in reliability evaluation is illustrated using a practical transmission system. The thesis presents an approach to identify weather specific contributions to system reliability indices and illustrates the technique by utilizing a test distribution system. The analysis of a range of reliability distributions with regard to major event day segmentation is presented.</p><p>The research work illustrated in this thesis clearly illustrates that reliability indices estimated without recognition of weather situations are unrealistic and that at minimum the three state weather model should be applied in reliability evaluation of systems residing in varying weather environments. The conclusions, concepts and techniques presented in this thesis should prove useful in practical application.</p>
13

Weather effect considerations in reliability evaluation of electrical transmission and distribution systems

Acharya, Janak Raj 02 September 2005 (has links)
<p>The weather environment has a significant impact on the reliability of a power system due to its effect on the system failure mechanisms of overhead circuits and on the operational ability of an electric power utility. The physical stresses created by weather increase the failure rates of transmission or distribution lines operating in adverse weather conditions, resulting in increased coincident failures of multiple circuits. Exceptionally severe weather can cause immense system damages and significantly impact the reliability performance. Recognition of the pertinent weather impacts clearly indicates the need to develop appropriate models and techniques that incorporate variable weather conditions for realistic estimation of reliability indices.</p> <p>This thesis illustrates a series of multi-state weather models that can be utilized for predictive reliability assessment incorporating adverse and extremely adverse weather conditions. The studies described in this thesis are mainly focused on the analyses using the three state weather model. A series of multi-state weather models are developed and utilized to assess reliability performance of parallel redundant configurations. The application of weather modeling in reliability evaluation is illustrated using a practical transmission system. The thesis presents an approach to identify weather specific contributions to system reliability indices and illustrates the technique by utilizing a test distribution system. The analysis of a range of reliability distributions with regard to major event day segmentation is presented.</p><p>The research work illustrated in this thesis clearly illustrates that reliability indices estimated without recognition of weather situations are unrealistic and that at minimum the three state weather model should be applied in reliability evaluation of systems residing in varying weather environments. The conclusions, concepts and techniques presented in this thesis should prove useful in practical application.</p>
14

Bus Bunching Prediction and Transit Route Demand Estimation Using Automatic Vehicle Location Data / バスロケーションデータを用いたバスバンチングの予測と路線バス利用者の需要推定に関する研究

Sun, Wenzhe 25 May 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22653号 / 工博第4737号 / 新制||工||1740(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 山田 忠史, 教授 藤井 聡, 准教授 SCHMOECKER Jan-Dirk / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
15

Electromigration induced step instabilities on silicon surfaces

Gibbons, Brian J., Jr 22 September 2006 (has links)
No description available.
16

Kinetically determined surface morphology in epitaxial growth

Jones, Aleksy K. 11 1900 (has links)
Molecular beam epitaxy has recently been applied to the growth and self assembly of nanostructures on crystal substrates. This highlights the importance of understanding how microscopic rules of atomic motion and assembly lead to macroscopic surface shapes. In this thesis, we present results from two computational studies of these mechanisms. We identify a kinetic mechanism responsible for the emergence of low-angle facets in recent epitaxial regrowth experiments on patterned surfaces. Kinetic Monte Carlo simulations of vicinal surfaces show that the preferred slope of the facets matches the threshold slope for the transition between step flow and growth by island nucleation. At this crossover slope, the surface step density is minimized and the adatom density is maximized, respectively. A model is developed that predicts the temperature dependence of the crossover slope and hence the facet slope. We also examine the "step bunching" instability thought to be present in step flow growth on surfaces with a downhill diffusion bias. One mechanism thought to produce the necessary bias is the inverse Ehrlich Schwoebel (ES) barrier. Using continuum, stochastic, and hybrid models of one dimensional step flow, we show that an inverse ES barrier to adatom migration is an insufficient condition to destabilize a surface against step bunching.
17

Kinetically determined surface morphology in epitaxial growth

Jones, Aleksy K. 11 1900 (has links)
Molecular beam epitaxy has recently been applied to the growth and self assembly of nanostructures on crystal substrates. This highlights the importance of understanding how microscopic rules of atomic motion and assembly lead to macroscopic surface shapes. In this thesis, we present results from two computational studies of these mechanisms. We identify a kinetic mechanism responsible for the emergence of low-angle facets in recent epitaxial regrowth experiments on patterned surfaces. Kinetic Monte Carlo simulations of vicinal surfaces show that the preferred slope of the facets matches the threshold slope for the transition between step flow and growth by island nucleation. At this crossover slope, the surface step density is minimized and the adatom density is maximized, respectively. A model is developed that predicts the temperature dependence of the crossover slope and hence the facet slope. We also examine the "step bunching" instability thought to be present in step flow growth on surfaces with a downhill diffusion bias. One mechanism thought to produce the necessary bias is the inverse Ehrlich Schwoebel (ES) barrier. Using continuum, stochastic, and hybrid models of one dimensional step flow, we show that an inverse ES barrier to adatom migration is an insufficient condition to destabilize a surface against step bunching.
18

Kinetically determined surface morphology in epitaxial growth

Jones, Aleksy K. 11 1900 (has links)
Molecular beam epitaxy has recently been applied to the growth and self assembly of nanostructures on crystal substrates. This highlights the importance of understanding how microscopic rules of atomic motion and assembly lead to macroscopic surface shapes. In this thesis, we present results from two computational studies of these mechanisms. We identify a kinetic mechanism responsible for the emergence of low-angle facets in recent epitaxial regrowth experiments on patterned surfaces. Kinetic Monte Carlo simulations of vicinal surfaces show that the preferred slope of the facets matches the threshold slope for the transition between step flow and growth by island nucleation. At this crossover slope, the surface step density is minimized and the adatom density is maximized, respectively. A model is developed that predicts the temperature dependence of the crossover slope and hence the facet slope. We also examine the "step bunching" instability thought to be present in step flow growth on surfaces with a downhill diffusion bias. One mechanism thought to produce the necessary bias is the inverse Ehrlich Schwoebel (ES) barrier. Using continuum, stochastic, and hybrid models of one dimensional step flow, we show that an inverse ES barrier to adatom migration is an insufficient condition to destabilize a surface against step bunching. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
19

所得變動之課稅方法研究

陳錦秀, CHEN, JIN-XIU Unknown Date (has links)
在現行所得稅制度下,由於課稅期間的規定,會計基礎的選擇篤累進稅率的採行,使 所得經常變動者負擔較多的租稅,而產生不公平的現象。此種不公平的現象導致人們 將所得費用在各期間們意移轉,以逃避過重的稅負,因而形成經濟效率的損失,所得 變動的集遽效果(BUNCHING EFFECT ),使資產的所得者不願變動其資產的持有,進 而形成緊銷效果(LOCKING-IN EFFECT ),減少資產的流動性,擾亂了資本市場的秩 序;另一方面,為了避免納稅者將所得及費用在期間們意移轉,若以法規加以限制, 不但交果不彰,反而增加了稅制複雜性,而使整個經濟體制的運作缺乏效率。因此多 婁字者均主張以所得平均法解決上重問題。 本文共分六章,第一章為導論:對所得變湩之課稅問題加以扼要說明;第二章對所得 變動發生課稅問題的原由及其影響作一番探討;第三章對所得變動之課稅問題提出一 些解決的方法,即所得平均法的介紹;第四章為美國平均法之歷史回顧,並對其引申 模型加以評介;第五章對我國所得變動之處理詳加評述,並對所得平均法在我國實施 之可三性作一綜合性論述;第六章為結論與建議。
20

Développement d'un refroidisseur-regroupeur quadripolaire radiofréquence pour PIPERADE et mesure de la demi-vie de 17F / Developpement of a radio-frequency quadrupole cooler and buncher for PIPERADE and half-life measurement of 17F

Guerin, Hugo 11 December 2014 (has links)
La future installation SPIRAL2 du GANIL, à Caen, permettra de produire une gamme étendue de noyaux exotiques avec des intensités très importantes. Cependant, ces faisceaux ne pourront pas être directement utilisés pour réaliser certaines études de haute précision et devront d'abord être purifiés. C'est pour réaliser ce travail que des équipes du CENBG, du MPIK (Heidelberg), du CSNSM, du LPC Caen, du GANIL et de l'IPNO développent un double-piège de Penning dans le cadre du projet PIPERADE. Ce double-piège nécessitant un travail de mise en forme préalable du faisceau (diminution de l'émittance transverse et mise en paquet), le CENBG est en charge de la réalisation d'un refroidisseur-regroupeur quadripolaire radiofréquence : le GPIB. C'est ce développement qui a constitué la majeure partie de mon travail de thèse, notamment en ce qui concerne les simulations de ce refroidisseur-regroupeur dont les résultats ont permis de trouver une méthode innovante pour la mise en paquet et de valider sa conception mécanique. Nous disposons également d'une source d'ions afin de pouvoir tester le GPIB et le double-piège et il m'a fallu la remonter, la comprendre et la caractériser pour que ces tests soient ensuite possibles. Dans un second temps j'ai aussi participer à l'analyse de l'expérience E622S menée au GANIL et qui avait pour but de déterminer précisément la demi-vie de 17F. Ce travail n'a pas permis d'améliorer la précision sur la demi-vie de 17F mais nous avons cependant quelques doutes sur les 2 précédentes mesures et sur leur détermination du taux de contamination de leurs échantillons. / The future SPIRAL2 installation of GANIL, at Caen, will produce large range of exotic nuclei with very high intensities. Nevertheless, these beams could not be used directly for some high precision studies and will have to be purified first. To achieve this work, teams of CENBG, MPIK (Heidelberg), CSNSM, LPC Caen, GANIL and IPNO develop a double Penning trap in the framework of the PIPERADE project. Because this double Penning-trap needs some shaping work (reduction of transverse emittance and bunching), the CENBG team is in charge of the realisation of a radio-frequency quadrupole cooler and buncher : the GPIB. This developpement work was the main part of my PhD work, especially for the simulations of this cooler buncher whose results lead us to find a new bunching method and allowed us to approve its mechanical design. We also have an ion source to be able to test both GPIB and Penning trap and I had to reassemble it, to understand it and to characterise it before these tests could be achieved. In a second time I also took part to the analysis of the E622S experiment which aimed to determined precisely the 17F half-life. This work did not lead to a more precise determination of this half-life but we now have some doubts concerning the 2 last measurements and their way to determine the contamination rate of their radioactive samples.

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