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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.
131

Micro-ring Device Design and Analysis With Large FSR and Narrow Passband

Lee, Yu-zhan 27 August 2012 (has links)
Micro-ring devices are based on resonance principle and inherently are wavelength selective. Thus it is an important optical component for WDM based applications. To fully utilize the available capacity in an optical network, large full spectral range (FSR) and narrow passband are key performance targets of ring device designs. In this paper we report the design and analysis results of micro-ring filters with 4000+ GHz FSR and 25 to 50 GHz passband, based on symmetric add-drop filter structure. We optimize the passband shape (using a box-like factor), drop loss coefficient and off-resonance through loss via the coupling coefficients and ring loss parameters.
132

A Climatology of Tropical Anvil and Its Relationship to the Large-Scale Circulation

Li, Wei 2009 December 1900 (has links)
This dissertation uses multiple tools to investigate tropical anvil, i.e., thick, non-precipitating cloud associated with deep convection with the main objectives to provide a climatology of tropics-wide anvil properties and a better understanding of anvil formation, and to provide a more realistic assessment of the radiative impact of tropical anvil on the large-scale circulation. Based on 10 years (1998-2007) of observations, anvil observed by the Tropical Rainfall Measuring Mission (TRMM) Precipitation (PR) shows significant geographical variations, which can be linked to variations in the parent convection. Strong upper level wind shear appears to assist the generation of anvil and may further explain the different anvil statistics over land and ocean. Variations in the large-scale environment appear to play a more important role in anvil production in regions where convection regularly attains heights greater than 7 km. For regions where convection is less deep, variations in the depth of the convection and the large-scale environment likely contribute more equally to anvil generation. Anvil radiative heating profiles are estimated by extrapolating millimeter cloud radar (MMCR) radiative properties from Manus to the 10-year TRMM PR record. When the unconditional anvil areal coverage is taken into account, the anvil radiative heating becomes quite weak, increasing the PR latent heating profile by less than 1 percent at mid and upper levels. Stratiform rain and cirrus radiative heating contributions increase the upper level latent heating by 12 percent. This tropical radiative heating only slightly enhances the latent heating driven model response throughout the tropics, but more significantly over the East Pacific. These modest circulation changes suggest that previous studies may have overemphasized the importance of radiative heating in terms of Walker and Hadley circulation variations. Further, the relationship of cloud radiative heating to latent heating needs to be taken into account for more realistic studies of cloud radiative forcing on the large-scale circulation.
133

Design of Decentralized Adaptive Sliding Mode Controllers for Large-Scale Systems with Mismatched Perturbations

Yu, Shih-Shou 13 July 2004 (has links)
A novel design methodology of a decentralized adaptive sliding mode control scheme for a class of large-scale systems with mismatched disturbances and uncertainties in each subsystem and interconnections is proposed in this thesis. The main idea of this new method is that the design of the switching surface of each subsystem is through the design of a pseudo-feedback controller which can stabilize the dynamics when system is in the sliding mode. The feedback gain of the pseudo controller then becomes a important parameter of switching surface. The proposed controllers of each subsystem contain three parts. The first part is measurable feedback signals, and the second part is an adaptive control mechanism, which is used for overcoming the disturbances and uncertainties of each subsystem and interconnections among subsystems. The information of upper bound of those disturbances and uncertainties are not required. The third part of the decentralized controllers is used for adjusting the convergent rate of state variables of the controlled system. The asymptotical stability is guaranteed for each subsystem even if the mismatched perturbations exist when employing the proposed control scheme. An example is demonstrated for showing the feasibility of the proposed methodology.
134

Design of Sliding Surfaces for A Class of Mismatched Perturbed Large-Scale Systems to Achieve Asymptotical Stability

Chang, Jen-Chen 01 August 2005 (has links)
A methodology of designing a novel sliding surface for a class of large-scale systems with matched and mismatched perturbations is proposed in this thesis. The main idea is that some adaptive mechanisms are embedded both in the sliding surface function and in the controllers, so that not only the mismatched perturbations are suppressed during the sliding mode, but also the information of upper bound of perturbation is not required except the upper bound of perturbation from input channel. The proposed controller of each subsystem contains two parts. The first part is measurable feedback signals, and the second part is an adaptive control mechanism, which is used for overcoming the perturbation of each subsystem as well as interconnections among subsystems. The dynamics of the controlled system can be driven into the sliding surface in a finite time, and the property of asymptotical stability of each subsystem is guaranteed. Two numerical examples are given to demonstrate the feasibility of the proposed methodology.
135

Design of Decentralized Adaptive Sliding Mode Output Tracking Controllers for a Class of Mismatched Perturbed Large-Scale Systems

Ke, Yi-Ming 20 January 2007 (has links)
Based on the Lyapunov stability theorem, a methodology of designing a decentralized multi-surface adaptive sliding mode control scheme is proposed in this thesis for a class of large-scale nonlinear systems with mismatched perturbations and interconnections. By utilizing the sliding mode control technique, the designed decentralized robust controller with adaptive mechanisms embedded enable the output of each subsystem to track its own desired output signal, and stabilize the whole large-scale system as well as each subsystem at the same time. In addition, the accuracy of output tracking can be adjusted through the designed parameter embedded in the controller. The purpose of the adaptive mechanisms included in the controller is to adapt the unknown upper bounds of perturbations and interconnections. Finally, two illustrative examples are given to demonstrate the feasibility of the proposed methodology.
136

none

Haung, Yen-yen 12 August 2009 (has links)
The analysis of the large-scale international multi-sports event and city development¡Ðtaking the 2009 World Games pre-events as examples. Since winning the right to host the 2009 World Games in June 2004, Taiwan has been making numerous preparations for the big event. During the preparation period, intense preparations and the support of human resource as well as material resource are essential. However, Taiwan is currently lacking of experienced organizations on hosting large-scale international sports events and un-unified affair right. The promotion of the central policy rarely takes into account the diverse local public opinion over an extended period of time, which causes the inappropriate resource allocation for local development. The preparation is full of difficulties because the central and local resources could not bring out the full beneficial result. This research aims to analyze the 2009 World Games pre-events by using the data and literature review analysis. It does not only improve the hardware and software of city¡¦s structure. It also offers the opportunity for citizens to interact with various cultures. The most important thing is increasing the centripetal force of the people in a short time and promoting Taiwan into the international stage. The key factor is the marketing tactics brought out by the sports event, which expresses concretely the cultural integration, united harmony and state consciousness of Taiwan. The marketing tactics brought out by sports event pushes the rapid development of the city appearance, creative and artistic livelihood, and sustainable environment and tourism industries. We hope to drive the economic development by hosting large-scale sports event. Our goal is to promote the city and show the vitality of entire city. The global participative sports event will bring the long-term benefit for the city economy. Kaohsiung should work harder in the future, striving actively for the right to host international event which helps internationalize the city, expand commercial possibilities, and gain people recognition.
137

Estudo sobre um efetivo controle da direção do lançamento com uma das mãos no basquetebol

Iracema, Paulo Murilo Alves, 1939- January 1992 (has links)
No description available.
138

A coordenação visuo-motora na sincronização de acções rápidas-aplicação ao estudo do remate de voleibol

Sardinha, Luís January 1992 (has links)
No description available.
139

A instrução e a estruturação das tarefas no treino de voleibol-estudo experimental no escalão de iniciados feminino

Silva, Isabel Maria Ribeiro Mesquita da January 1998 (has links)
No description available.
140

O ressalto no basquetebol-análise do comportamento do lançador

Barreto, Hermínio January 1995 (has links)
No description available.

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