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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.
101

none

Chen, Hsiu-Feng 22 August 2003 (has links)
none
102

The Cost of Right-of-Way acquisitions for transportation projects : switching models for condemnation versus negotiated settlement / Switching models for condemnation versus negotiated settlement

Xiong, Xiaoxia 25 June 2012 (has links)
The costs of acquiring parcels by condemnation are usually significantly higher than those for property acquired by negotiation, suggesting that Right-of-Way (R/W) acquisition costs may best be described by two different regression equations. This paper develops a switching regression model of acquisition cost to simultaneously predict the probability of whether a parcel will go to condemnation rather than be acquired via negotiation and the corresponding acquisition costs under these two regimes. The error terms of the selection equation and the two cost equations follow a trivariate normal distribution to reflect correlations across unobserved factors (such as a land owner's tenacity or a site's view value). When this model is calibrated using data on properties acquired across the state of Texas for transportation projects between 2008 and 2011, results suggest that R/W appraisers and staff should pay special attention to commercially used parcels in urban areas involving a partial taking with a relatively small remainder. Comparison of cost estimates between the two regimes (condemnation vs. negotiation) suggests that condemned parcels will have, on average, 78% higher acquisition costs across the 1,710 acquired properties and 51% greater price variation. These results suggest that it is much more costly to acquire a property and more difficult to accurately predict its costs if it cannot be acquired via negotiation. The application of model estimates to an example corridor highlights the value of simulation to capture all modeling uncertainties. This two-regime model is further extended to a three-category multinomial endogenous switching, allowing for differential cost estimates across negotiation-deed, administrative settlement, and condemnation contexts. A model of acquisition time -- from the agency's initial-offer date to its final possession date is also developed, to examine the effects of condemnation on acquisition duration. The results suggest that condemnation proceedings add approximately 7 to 8 months, on average, to parcel acquisitions by the Texas Department of Transportation. Taken together, such switching models for condemnation versus negotiated settlement highlight the benefits of avoiding condemnation proceedings in R/W acquisition. Estimation results illuminate the relative importance of various parcel and owner attributes, impacting the nature and cost of acquisition, and enhancing opportunities for R/W staff to identify more contentious properties and establish more reliable budget estimates. / text
103

Exploring the limits of star formation from the extreme environment of galaxy interactions to the Milky Way

Heiderman, Amanda Lea 29 January 2013 (has links)
In this thesis, I explore the rate at which molecular gas is converted to stars through detailed studies of a sample of molecular clouds in the Milky Way, IFU spatially resolved observations of gas-rich nearby interacting galaxies, as well as the environmental dependence of star formation and galaxy morphology in a galaxy supercluster. This thesis is composed of three individual projects that investigate nearby star formation within the local 500 pc of our Sun, to neighboring extreme star forming environments of interacting starburst galaxies, and finally studying how star formation varies with galaxy morphology in a galaxy supercluster a z~0.165. I discuss the relation between the star formation rate (SFR) and molecular gas surface densities (e.g., Schmidt-Kennicutt relation) in Galactic star forming regions and find there is a discrepancy between my study and extragalactic relations. The discrepancy is attributed to extragalactic measurements that are averaged over large >kpc scales and include star forming molecular gas (above some threshold) and molecular gas the is not dense enough to form stars. I find a steep increase in the Galactic SFR-gas surface density relation indicative of a threshold for efficient star formation that is best fit to a broken power law with a linear slope above 129 Msun pc⁻². I introduce the VIRUS-P Investigation of the eXtreme ENviroments of Starbursts (VIXENS) project which is a survey of interacting is a large integral field unit survey of nearby infrared bright (L_IR>3x10¹⁰ Lsun) interacting/starburst galaxies. The main goal of VIXENS is to investigate the relation between star formation and gas content on spatially resolved scales of ~0.1-1 kpc in the extreme star forming environments of interacting/starburst galaxies. The VIXENS sample is composed of systems in a range interaction stages with morphological signatures from early phase (close pairs) to late stage mergers (single system with multiple nuclei), SFRs, and gas surface densities. I highlight the first results from the VIXENS survey in the late interaction phase galaxy merger Arp 299. I find 1.3 kpc regions in Arp 299 to lie along the SFR-gas surface density relation found for mergers at high redshift, but this relation is highly dependent on the CO to molecular hydrogen (H₂) conversion factor. I find evidence for a Galactic CO-to-H₂ conversion factor using metallicity and dust temperature measurements, which would place 1.3 kpc regions in the Arp 299 merger in between the high redshift and Kennicutt-Schmidt relations. Comparing the SFR to dense gas surface densities as traced by HCN and HCO⁺, I find an agreement between the spatially resolved measurements and that found on global scales in spirals and (ultra)luminous infrared galaxies. Finally, I present an investigation of the influence of environment on frequency, distribution, color, and star formation properties of galaxy mergers and non-interacting galaxies in the Abell 901/902 supercluster at z~0.165. I find galaxy mergers be preferentially blue in color and have an enhanced SFR by a factor of ~2 compared to non-interacting galaxies. This result may be due to a decrease in galaxy velocity dispersion in the cluster outskirt, favoring galaxy-galaxy interactions, or to interacting galaxies that are part of groups or field galaxies being accreted along cosmological filaments by the clusters. I compare to N-body simulations of groups and field galaxies accreting onto the clusters and find the fraction of mergers are similar to that predicated at group overdensities. I find the SFR of galaxies in the supercluster to be depressed compared to field galaxies in both the core and cluster outskirts, suggesting that an environmental process such as ram pressure stripping is effective throughout the cluster. The results of a modest SFR enhancement and a low merger fraction culminate in my finding that mergers contribute only a small fraction (between 10% and 15%) of the total SFR density of the Abell 901/902 clusters. / text
104

Unconditional Relationships within Zero Knowledge

Ong, Shien Jin 09 September 2011 (has links)
Zero-knowledge protocols enable one party, called a prover, to "convince" another party, called a verifier, the validity of a mathematical statement such that the verifier "learns nothing" other than the fact that the proven statement is true. The different ways of formulating the terms "convince" and "learns nothing" gives rise to four classes of languages having zero-knowledge protocols, which are: statistical zero-knowledge proof systems, computational zero-knowledge proof systems, statistical zero-knowledge argument systems, and computational zero-knowledge argument systems. We establish complexity-theoretic characterization of the classes of languages in NP having zero-knowledge argument systems. Using these characterizations, we show that for languages in NP: -- Instance-dependent commitment schemes are necessary and sufficient for zero-knowledge protocols. Instance-dependent commitment schemes for a given language are commitment schemes that can depend on the instance of the language, and where the hiding and binding properties are required to hold only on the YES and NO instances of the language, respectively. -- Computational zero knowledge and computational soundness (a property held by argument systems) are symmetric properties. Namely, we show that the class of languages in NP intersect co-NP having zero-knowledge arguments is closed under complement, and that a language in NP has a statistical zero-knowledge **argument** system if and only if its complement has a **computational** zero-knowledge proof system. -- A method of transforming any zero-knowledge protocol that is secure only against an honest verifier that follows the prescribed protocol into one that is secure against malicious verifiers. In addition, our transformation gives us protocols with desirable properties like having public coins, being black-box simulatable, and having an efficient prover. The novelty of our results above is that they are **unconditional**, meaning that they do not rely on any unproven complexity assumptions such as the existence of one-way functions. Moreover, in establishing our complexity-theoretic characterizations, we give the first construction of statistical zero-knowledge argument systems for NP based on any one-way function.
105

The fourteen principles of the Toyota Way

Chacon, Andrez C. 22 December 2010 (has links)
The thesis is aimed at discussing the principles of the Toyota Way, philosophy and system of management guidelines, by way of elaborating and evaluating upon its fourteen core principles that are followed by companies worldwide. Further, the discussion will throw light on why the systemic root cause of the multiple recalls of 2009 and 2010 was not due to their concepts of lean manufacturing but can be attributed to the inability of the management of Toyota Motor Corporation to thoroughly apply their core principles. / text
106

Improving right-of-way acquisition in highway projects through scope definition and management of inherent factors

Le, Tiendung 24 March 2011 (has links)
Right-of-Way (R/W) acquisition is a critical function in the project development process (PDP). Improving this acquisition process requires both a good collaboration among the functions of the PDP and a good understanding of the factors affecting R/W acquisition. This research has two phases. Phase I aims at developing a systematic method for risk and scope management using scope elements that cover the work of all functions of the entire PDP. Phase II aims at studying the inherent factors that might have significant impact on the R/W acquisition schedule. As a result, the Advance Planning Risk Analysis (APRA) was successfully developed. It contains 59 scope elements with descriptions and a mechanism to assess the project’s level of definition. The APRA can provide a platform for project participants to cooperate and coordinate project activities and responsibilities. The method provides a high level approach to improving the effective of the PDP and its functions, including R/W acquisition. In studying the R/W acquisition inherent factors in phase II, the research was able to draw conclusions on the impact of the identified inherent factors on R/W acquisition durations based on statistical analyses. The research was also successful in developing a statistically significant model for predicting the total R/W acquisition duration, from R/W Release to Possession, using inherent factors. This research provides a number of significant contributions toward the better understanding and improvement of the PDP process in general and the R/W acquisition process in particular. Further research in this area and direction was recommended and believed to be promising, productive, and highly valuable. / text
107

Physical properties of star-forming regions across the Galaxy

Dunham, Miranda Kay 13 June 2011 (has links)
The Bolocam Galactic Plane Survey (BGPS) has surveyed the northern Galactic plane at 1.1 mm and detected 8,358 sources. The BGPS catalog is large enough to characterize the properties of massive star formation in a statistically significant way. In this dissertation, I have conducted a survey of NH₃ lines toward 771 BGPS sources located throughout the Galactic plane. The NH₃ and 1.1 mm continuum observations together have allowed for complete characterization of the physical properties of these sources. I detected the NH₃(1,1) line toward 408 BGPS sources in the inner Galaxy, allowing for determination of their kinematic distances. At distances less than roughly 1 kpc, the BGPS detects predominately cores which will form a single star or small multiple system, while at distances between 1 and 7 kpc the BGPS detects predominately clumps which will form entire stellar clusters. At distances greater than 7 kpc, the BGPS detects the large scale clouds which contain clumps and cores. I have correlated the BGPS catalog with mid-IR catalogs of massive young stellar objects (MYSOs), and found that 49% of the BGPS sources contain signs of active star formation. The masses, densities, H₂ and NH₃ column densities, gas kinetic temperatures, and NH₃ velocity dispersions are higher in BGPS sources with associated mid-IR sources. I have also studied the physical properties of the BGPS sources as a function of Galactocentric radius, R[subscript Gal]. I find that the mean radius and mass decrease with increasing R[subscript Gal] but peak within the 5 kpc molecular ring where the gas kinetic temperature reaches a minimum. The fraction of BGPS sources with associated mid-IR sources decreases by 10% within the molecular ring. I postulate that these trends can be explained by an ambient gas density which decreases with R[subscript Gal], but peaks within the molecular ring. Similarly, the NH₃ column density and abundance decrease by almost an order of magnitude from the inner to outer Galaxy. / text
108

Public highway vs private property boundaries

Huckelberry, C. H. (Charles Howard), 1949- January 1976 (has links)
No description available.
109

Lekens magi! : Synen på lekens betydelse för lärandeprocesser bland pedagoger på en Reggio Emilia- respektive Montessoriförskola / The magic of play!

Yildiz, Alev January 2010 (has links)
This study deals with play and the importance of meaning of play in the learning process. The aim is to look in to and analyze four preschool teacher´s beliefs and views about the importance of play for children´s learning and development. The study looks at two different preschools, one based on Reggio Emilia- and the other on Montessori- pedagogy, and the aim is to compare the different views and ways of working that the preschool educators have. The theoretical basis for this study is both rooted in a socio-cultural and constructivist perspective, and deals with the relationships between theoretical concepts mean as play, learning, way of working and pedagogy. The study is based on qualitative research methods that consist of interviews and participant observations. The person’s participants in the study consisted of four active preschool educators, who work in two different preschools. The results of the investigation show that the educators have similar views on the importance of play for the children´s learning process, and this also applies to their way of working. In the interviews, they emphasize the importance of observing the child, and to start from the child´s own interests and the free play, when working with the children. But the implementation of their work differed in the sense that the Reggio Emilia- preschool educators work with theme works that extended over longer periods while the Montessori- preschool educators worked with free play.
110

Seguimiento cuantitativo de procesos de degradación de contaminantes orgánicos fotosensibles mediante fluorescencia molecular y métodos de ánalisis de dptos de múltiples vías

Bosco Costa, Marta Verónica 03 December 2008 (has links)
En esta Tesis Doctoral, se aborda la aplicación de metodologías de análisis de datos de múltiples vías, a datos tridimensionales de fluorescencia molecular de excitación-emisión obtenidos a lo largo de una reacción, para obtener de forma rápida información de interés en el desarrollo de técnicas basadas en procesos de eliminación oxidativa de contaminantes orgánicos. Se afrontan dos casos en particular: la foto-degradación de una mezcla de hidrocarburos policíclicos aromáticos (benzo[a]antraceno, benzo[a]pireno, benzo[k]fluoranteno, dibenzo[a,h]antraceno)y la foto-catálisis del fenol. Los espectros de fluorescencia de excitación y emisión registrados para cada muestra analizada constituyen una matriz o datos de segundo orden. Información cualitativa y cuantitativa acerca de las especies que participan en los procesos en estudio se ha extraido trabajando con métodos de análisis multivariante, que permiten analizar datos de múltiples vías como son el método de resolución de curvas basado en el análisis de factores paralelo (PARAFAC)yelbasadoenlaoptimizaciónpormínimoscuadrados(M CR -ALS),asícomoel método de calibración multivariante en mínimos cuadrados parciales para datos de múltiples vías (N -PLS). En la Tesis doctoral se realiza un análisis comparativo de los resultados encontrados por lo diferentes métodos de análisis multivariante. Los resultados encontrados fueron validados al comparar los resultados con los obtenidos cuando el seguimiento cuantitativo se realizaba mediante cromatografía líquida de alta resolución (H PLC), considerada como técnica de referencia para el seguimiento de este tipo de reacciones. La rapidez que aportan estas metodologías es una característica valiosa en estudios de optimización de dichos procesos. En esta Tesis empleando estas metodologías para el cálculo de constantes cinéticas se ha abordado el análisis simultáneo, empleando técnicas de diseño de experimentos, de variables de interés en el desarrollo de los procesos de foto-degradación. Del estudio realizado se derivan los siguientes resultados: *En la foto-degradación de una mezcla de hidrocarburos poli cíclicos aromáticos se evidenció la interacción de las variables experimentales y la importancia del análisis conjunto de sus efectos sobre el proceso para la selección de las condiciones óptimas de trabajo. En el dominio experimental en estudio, se encontró que la degradación es más rápida cuando se trabaja a pH ácido utilizando etanol como solvente e irradiando con una lámpara de baja presión de mercurio. *Tanto al aplicar PARAFAC como M CR -ALS el número de factores significativos fue de cuatro, uno por cada analito presente en la muestra. La bondad de los espectros recuperados en ambos casos fue evaluada calculando el coeficiente de similitud que resultó tener valor superior a 0.98 en todas las situaciones. Cuando los valores de concentración obtenidosenelprocesodedegradaciónmediantePARAFACoM CR -ALSaplicadosadatos EEM fueron representados frente a los obtenidos mediante H PLC se obtuvo una línea de regresión mediante mínimos cuadrados, con pendiente próxima a 1 e intercesión en el origen próxima a 0. El test conjunto de la pendiente y la ordenada en el origen para corroborar la ausencia de sesgo fue superado para todos los analitos. *En la determinación del fenol y sus dihidroxiderivados el error de predicción global tanto para PARAFAC como para M CR -ALS, era admisible y de ello se concluye que es posible realizar un seguimiento rápido y cuantitativo de la concentración del fenol y de la concentración de sus intermediarios, catecol, resorcinol e hidroquinona en un proceso de foto-degradación a partir de sus espectros fluorescentes de excitación-emisión. *El fenol y la hidroquinona se resuelven perfectamente y se obtienen errores bajos a los diferentes niveles de concentración analizados, mientras que catecol y el resorcinol que están fuertemente solapados presentan errores significativamente mayores. * Con el propósito de analizar si los errores encontrados fundamentalmente para el catecol y resorcinol eran susceptibles de mejora, se trabajó con mínimos cuadrados parciales para datos de múltiples vías (N -PLS), en particular tri-PLS1. Los valores encontrados de aplicar este método y los anteriormente descritos a un nuevo conjunto de mezclas representativas del proceso en estudio fueron comparados en términos del error global cometido. *El análisis de los efectos de las variables implicadas en el proceso de degradación en estudio:tipo de catalizador, pH del medio y concentración del sustrato en la constante de velocidad de la reacción permitió concluir que todas ellas interaccionan entre sí y la importancia de sus efectos resultó significativa a un nivel de confianza del 95% cuando se realizó un test estadístico A N O V A . A partir de los resultados encontrados en el desarrollo de esta Tesis, hemos corroborado que la utilización conjunta de la espectrofluorimetría de EEM y la aplicación de diferentes métodos de análisis de datos de múltiples vías, es una opción válida y atractiva para la monitorización cuantitativa de la foto-degradación de una mezcla de hidrocarburos policíclicos aromáticos y de la evolución de la degradación foto-catalítica del fenol y sus intermediarios, así como para el análisis cinético de los procesos estudiados .

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