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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.
21

Data Extrapolation in the FDTD Method

Lan, Zhi-yang 29 June 2004 (has links)
The Finite-Difference Time-Domain method ( FDTD ) is a numerical method introduced by K. S. Yee in 1966. However , it needs so much time to simulate circuits by applying the FDTD method and some extensional methods for simulating circuits are still incomplete . Therefore, the author combine the FDTD method with the data extrapolation method to improve the simulation effect. When applying the FDTD method to simulate circuits, it needs a large number of time steps; furthermore, if the structure we simulated is complicated, the simulation time will be so much longer that the efficiency of simulation will be bad as well. The author decrease the number of time steps of the FDTD method, and then extrapolate the time-domain data to reconstruct the complete frequency response, therefore, we can save the simulation time as well because the number of the time steps of the FDTD method decreased. Furthermore, in the thesis, we also introduce a new FDTD method combined with the S-parameter Matrix, called ¡§S-parameter Matrix method¡¨. People can simulate circuits without deriving the equivalent circuit by applying the S-parameter Matrix method. One only have to obtain the S-parameter Matrix by measurement, data sheet, calculation, etc, and then we translate it to time domain data by the IFT technique to apply the FDTD calculation , this way, we avoid the difficulty of deriving the equivalent circuit of general microwave circuits. However, the S-parameter data we can obtain are often limited in a finite bandwidth, we make it to be extrapolated to obtain the complete time-domain response, and this way, the S-parameter Matrix method can by apply to simulate circuits.
22

Quelques contributions sur l'approximation rationnelle et les méthodes d'extrapolation

Matos, Ana Christina Brezinski, Claude January 2007 (has links)
Reproduction de : Habilitation à diriger des recherches : Sciences mathématiques : Lille 1 : 2006. / N° d'ordre (Lille 1) : 532. Résumé. Titre provenant de la page de titre du document numérisé. Bibliogr. p. 101-107. Liste des publications.
23

Localised splitting criteria for classification and regression trees /

Bremner, Alexandra P. January 2004 (has links)
Thesis (Ph.D.)--Murdoch University, 2004. / Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 172-182.
24

Graphical perception of nonlinear trends : discrimination and extrapolation /

Best, Lisa A., January 2001 (has links)
Thesis (Ph. D.) in Psychology--University of Maine, 2001. / Includes vita. Includes bibliographical references (leaves 162-174).
25

A study of reactivity changes in the AGN-20l reactor using perturbation theory

Sager, David Alan. January 1969 (has links) (PDF)
Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 1069. / Thesis Advisor(s): Marto, P. J. "June 1969." Description based on title screen as viewed on June 2, 2010. DTIC Descriptor(s): (Research Reactors, Reactor Reactivity), Reactor Cores, Fuel Burn Up, Fission Product Poisoning, Polyethylene Plastics, Perturbation Theory, Computer Programs, Theses. Author(s) subject terms: Perturbation, Polyethylene, Fermi Age, Extrapolation, Neutron Temperature, Samarium. Includes bibliographical references (p. 88). Also available in print.
26

The Phantoms that Chase Us: Judicialization of Arbitration: A Latent or Overcome Problem? / Los Fantasmas que nos Persiguen: Judicialización del Arbitraje: ¿Un Problema Latente o Superado?

Limas Calderón, Sherin 10 April 2018 (has links)
This article is about the situation of the arbitration activity in Peru and how this development is affected by the phenomenon of the Judicialization. In the first part of the article, it questioned the jurisdiction attributed to arbitration. In the second part it approaches the theories of the nature of arbitration and its importance. Finally, it concludes with the concept of the judicialization and its impact on the arbitration.
27

Caracterização e aplicação de duas câmaras de extrapolação em feixes padronizados de radiação X / Characterization and application of two extrapolation chambers in standard X radiation beams

SILVA, ERIC A.B. da 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:24Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:24Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
28

Caracterização e aplicação de duas câmaras de extrapolação em feixes padronizados de radiação X / Characterization and application of two extrapolation chambers in standard X radiation beams

SILVA, ERIC A.B. da 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:24Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:24Z (GMT). No. of bitstreams: 0 / As câmaras de extrapolação são câmaras de ionização com volume variável e são utilizadas principalmente como detectores de radiação beta. Neste trabalho foram caracterizadas duas câmaras de extrapolação, uma comercial da marca PTW, e uma outra desenvolvida no Laboratório de Calibração do IPEN, para aplicação como sistemas de referência em feixes de mamografia, radiodiagnóstico convencional e radioterapia. Os resultados obtidos nos testes de caracterização da resposta das câmaras de extrapolação: corrente de fuga, estabilidade de curto e médio prazos, determinação das correntes de saturação e das eficiências de coleção de íons, dependência angular e energética, mostram que estas câmaras de extrapolação podem ser utilizadas em dosimetria de feixes de radiação X de energias baixas. Os fatores de transmissão no tecido e os fatores de calibração foram também determinados para todas as qualidades de radiação citadas. Finalmente, foi estabelecido um procedimento de calibração de detectores de radiação em feixes padronizados de radiação X, utilizando as câmaras de extrapolação. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
29

An efficient method for an ill-posed problem [three dashes]band-limited extrapolation by regularization

Chen, Weidong January 1900 (has links)
Doctor of Philosophy / Department of Mathematics / Robert B. Burckel / In this paper a regularized spectral estimation formula and a regularized iterative algorithm for band-limited extrapolation are presented. The ill-posedness of the problem is taken into account. First a Fredholm equation is regularized. Then it is transformed to a differential equation in the case where the time interval is R. A fast algorithm to solve the differential equation by the finite differences is given and a regularized spectral estimation formula is obtained. Then a regularized iterative extrapolation algorithm is introduced and compared with the Papoulis and Gerchberg algorithm. A time-frequency regularized extrapolation algorithm is presented in the two-dimensional case. The Gibbs phenomenon is analyzed. Then the time-frequency regularized extrapolation algorithm is applied to image restoration and compared with other algorithms.
30

Segmentace 2D Point-cloudu pro proložení křivkami / 2D Point-cloud segmentation for curve fitting

Šooš, Marek January 2021 (has links)
The presented diploma thesis deals with the division of points into homogeneous groups. The work provides a broad overview of the current state in this topic and a brief explanation of the main segmentation methods principles. From the analysis of the articles are selected and programmed five algorithms. The work defines the principles of selected algorithms and explains their mathematical models. For each algorithm is also given a code design description. The diploma thesis also contains a cross comparison of segmentation capabilities of individual algorithms on created as well as on measured data. The results of the curves extraction are compared with each other graphically and numerically. At the end of the work is a comparison graph of time dependence on the number of points and the table that includes a mutual comparison of algorithms in specific areas.

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