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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.
361

Simultaneous calibration of a microscopic traffic simulation model and OD matrix

Kim, Seung-Jun 30 October 2006 (has links)
With the recent widespread deployment of intelligent transportation systems (ITS) in North America there is an abundance of data on traffic systems and thus an opportunity to use these data in the calibration of microscopic traffic simulation models. Even though ITS data have been utilized to some extent in the calibration of microscopic traffic simulation models, efforts have focused on improving the quality of the calibration based on aggregate form of ITS data rather than disaggregate data. In addition, researchers have focused on identifying the parameters associated with car-following and lane-changing behavior models and their impacts on overall calibration performance. Therefore, the estimation of the Origin-Destination (OD) matrix has been considered as a preliminary step rather than as a stage that can be included in the calibration process. This research develops a methodology to calibrate the OD matrix jointly with model behavior parameters using a bi-level calibration framework. The upper level seeks to identify the best model parameters using a genetic algorithm (GA). In this level, a statistically based calibration objective function is introduced to account for disaggregate form of ITS data in the calibration of microscopic traffic simulation models and, thus, accurately replicate dynamics of observed traffic conditions. Specifically, the Kolmogorov-Smirnov test is used to measure the "consistency" between the observed and simulated travel time distributions. The calibration of the OD matrix is performed in the lower level, where observed and simulated travel times are incorporated into the OD estimator for the calibration of the OD matrix. The interdependent relationship between travel time information and the OD matrix is formulated using a Extended Kalman filter (EKF) algorithm, which is selected to quantify the nonlinear dependence of the simulation results (travel time) on the OD matrix. The two test sites are from an urban arterial and a freeway in Houston, Texas. The VISSIM model was used to evaluate the proposed methodologies. It was found that that the accuracy of the calibration can be improved by using disaggregated data and by considering both driver behavior parameters and demand.
362

Construction of Scalable Macro-models of Interconnects Using the Time-Domain Pencil of Matrix Method

Wu, Che-Ching 29 July 2009 (has links)
As the circuit density and clock rate in SIP or SOC getting higher, the crosstalk interference between interconnects becomes more and more serious. This results in the degradation of signal integrity. Full wave simulation softwares such as HFSS are often used to analyze the characteristics of the transmission system, but the computation time is relatively long and it is difficult to integrate with active circuits. On the other hand, circuit simulation softwares such as ADS has the advantages of simplicity and needs less simulation time. The circuit simulation softwares is so far the best tool of designing high speed circuits. Usually obtain scalable equivalent macro-model in the existing literature with the technology of the frequency-domain, but using the technology of the time-domain to construct scalable equivalent macro-model have more direct, convenient and low-cost. Therefore, considering cost and practicability, this thesis develops a systematic method using the method of Pencil Matrix in time domain to obtain the scalable broadband equivalent macro-model of the components of high-speed interconnect structures. The developed macro-models can be applied to existing simulation softwares for a fast and accurate analysis of systems such as SIP.
363

Influence of the electron effective mass distribution on the application of the extended WKB approximation method

Chen, Chih-yuan 30 July 2009 (has links)
The position-dependent effective mass (PDEM) problem is of enormous importance to the realization of the extended Wentzel-Kramers-Brillouin (WKB) approximation in bound state calculations for semiconductor heterostructures. By studying some model problems, we show that the extended WKB method provides good approximations for the bound states with the high eigenenergies. In addition, the effect of the smoothness of the effective mass distribution functions and potential barrier in the PDEM problems is discussed in our work. We found the precision can be affected by the effective mass and potential barrier in the PDEM.
364

The Mott-Anderson transition in the disordered one-dimensional Hubbard model

Pai, R. V., Punnoose, A., Römer, R. A. 30 October 1998 (has links) (PDF)
We use the density matrix renormalization group to study the quantum transitions that occur in the half-filled one-dimensional fermionic Hubbard model with onsite potential disorder. We find a transition from the gapped Mott phase with algebraic spin correlations to a gapless spin-disordered phase beyond a critical strength of the disorder 1 c ss U= 2. Both the transitions in the charge and spin sectors are shown to be coincident. We also establish the finite-size corrections to the charge gap and the spin-spin correlation length in the presence of disorder and using a finite-size-scaling analysis we obtain the zero temperature phase diagram of the various quantum phase transitions that occur in the disorder-interaction plane.
365

Model substrates for mechanistic studies of cell-matrix interactions /

Houseman, Benjamin Thomas. January 2001 (has links)
Thesis (Ph. D.)--University of Chicago, Dept. of Chemistry, June 2001. / Includes bibliographical references. Also available on the Internet.
366

Tissue engineering cellularized silk-based ligament analogues

Sell, Scott. January 1900 (has links)
Thesis (Ph.D.)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Biomedical Engineering. Title from resource description page. Includes bibliographical references.
367

The effect of adipokines on collagens and matrix metalloproteinases in rat cardiac cells /

Wong, Man Chee Maggie. January 2007 (has links)
Thesis (M.Sc.)--York University, 2007. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 119-133). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR38842
368

Cellular and extracellular matrix characteristics of canine chondrocytes in pathologic conditions

Kuroki, Keiichi, January 2003 (has links)
Thesis (Ph. D.)--University of Missouri--Columbia, 2003. / Typescript. Vita. Includes bibliographical references.
369

Application of the historic preservation index strategy to historic vernacular landscape

Parmar, Sonal D. January 2008 (has links)
Thesis (M.L.A.) -- University of Texas at Arlington, 2008.
370

Cellular and extracellular matrix characteristics of canine chondrocytes in pathologic conditions /

Kuroki, Keiichi, January 2003 (has links)
Thesis (Ph. D.)--University of Missouri--Columbia, 2003. / "May 2003." Typescript. Vita. Includes bibliographical references.

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