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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.
441

Concepts for coupling hydrological and meteorological models

Mölders, Nicole 06 December 2016 (has links) (PDF)
Earth system modeling, climate modeling, water resource research as well as integrated modeling (e.g., climate impact studies) require the coupling of hydrological and meteorological models. The paper presents recent concepts on such a coupling. It points out the difficulties to be solved, and provides a brief overview on recently realized couplings. Furthermore, a concept of a hydrometeorological module to couple hydrological and meteorological models is introduced. / Wasserresourcenforschung, Erdsystem- und Klimamodellierung sowie integrierte Modellierung (z.B. Klimafolgenforschung) erfordern das Koppeln von hydrologischen und meteorologischen Modellen. Dieser Artikel präsentiert Konzepte für eine solche Kopplung. Er zeigt die zu lösenden Schwierigkeiten auf und gibt einen kurzen Überblick über bisher realisierte Kopplungen. Ferner stellt er ein Konzept für einen hydrometeorologischen Moduls zur Kopplung von hydrologischen mit meteorologischen Modellen vor.
442

Chinese Stock Markets: Underperformance and its Determinants / Chinese Stock Markets: Underperformance and its Determinants

Kováč, Roman January 2015 (has links)
Performance of stock markets is determined by three classes of variables: macroeconomic indicators, industry & firm heterogeneity and third country effects. When assessing performance of a stock market index, impact of industry & firm heterogeneity is marginal as it is already embedded in the index through its constituent companies. This paper will therefore focus on the other two. Chinese stock market was selected as an application as their performance compared to other domestic indicators (mainly GDP growth) is considered inferior by many researchers. Using econometric framework for panel data and a Bayesian extension, the paper estimates multiple models of Chinese stock market performance examining individual determinants of it. Subsequently, it predicts development of theoretical prices of two main Chinese stock indices on two time samples until 2013. The paper then demonstrates underperformance of Chinese stock market by comparing the modeled prices to actual prices realized on the market. JEL Classification C23, C51, C53, G15, G17 Keywords underperformance, panel data, fixed effects model, Bayesian Model Averaging Author's e-mail roman_kovac@ymail.com Supervisor's e-mail karel.bata@seznam.cz
443

Matematický model proudění ovlivněného cirkulačními vrty / Mathematical model of groundwater flow affected by circulation wells

Nedvěd, Jakub January 2014 (has links)
In this thesis, I focused on numerical modelling of groundwater flow in the vicinity of groundwater circulation well (GCW). The thesis can be devided to two parts. In the first one, I created a simple numerical model of GCW. I used a cylindrical flow domain because of the radial symmetry of the problem. The task was to find out which parameters have the biggest influence on groundwater flow. It was found that the hydrogeological settings and hydraulic properties have more considerable effect on GW flow than the well construction parameters. Distance between the well screens is the only important construction parameter, other parameters can be neglected. However, we cannot neglect the influence of hydraulic properties of the porous medium. Considering the radius of influence of GCW, the presence of aquitards and anisotropy of layers affect the groundwater flow around the well seriously. These two parameters cause the extension of the radius of influence, which leads to a longer path of the particle of water. The travel time of particles increases too this slows down the remediation. A big influence has also an intensity of natural groundwater flow in the area because it decreases the radius of influence of the well. In the second part I created a numerical model of pilot site Velká Hleďsebe to investigate...
444

Determinants of Economic Growth: A Bayesian Model Averaging

Kudashvili, Nikoloz January 2013 (has links)
MASTER THESIS Determinants of Economic Growth: A Bayesian Model Averaging Author: Bc. Nikoloz Kudashvili Abstract The paper estimates the economic growth determinants across 72 countries using a Bayesian Model Averaging. Unlike the other studies we include debt to GDP ratio as an explanatory variable among 29 growth determinants. For given values of the other variables debt to GDP ratio up to the threshold level is positively related with the growth rate. The coefficient on the ratio has nearly 0.8 posterior inclusion probability suggesting that debt to GDP ratio is an important long term growth determinant. We find that the initial level of GDP, life expectancy and equipment investments have a strong effect on the GDP per capita growth rate together with the debt to GDP ratio.
445

Biomechanická reflexe scaffoldu na mechanické zatěžování / Biomechanical response of scaffold on mechanical loading

Anděrová, Jana January 2014 (has links)
The purpose of this work is to identify the parameters of scaffold's mechanical properties by observing/monitoring their response to defined external mechanical strain. The first part of the work is summarizing the knowledge about the required properties of scaffolds, their production and the factors influencing production. The practical part of the work concerns itself with measurement, analysis and evaluation of data based on proprietary methodology. Based on the results at this stage of the research, we can confirm, that scaffolds have viscoelastic, or viscoplastic character and its response depends on the magnitude of deformation, state of hydration, ratio of solutions and period of networking. Keywords: scaffod, tensile test, rheologic model
446

Modelování výnosů bank / Banks' Income Modelling

Lelovská, Adriána January 2013 (has links)
Bank profitability is one of the key inputs for macroprudential surveillance. Although we may find extensive empirical literature analyzing banks' performance, there is to our knowledge no study examining whole banking sectors. This thesis contributes to the existing research twofold. Firstly, we develop a banks' income model that considers banking sectors as a whole, using a sample of 40 countries in the period of 1997 to 2011. Secondly, we implement this model to two different restrictions of our data sample testing the model's applicability. We explore three hypotheses. Firstly, we test whether macroeconomic, industry-specific and bank-specific determinants are significant drivers of bank profitability. The final banks' income model is estimated via a dynamic GMM specification, consisting of proxies for the level of economic development, capitalization, interest-earning activities, credit quality and two lags of profitability capturing its persistency. The hypothesis is rejected since we do not find evidence of a significant industry-specific indicator. The second and third hypotheses restrict our sample to a time period before the financial crisis and banking sectors comprising only commercial banks, respectively. We conclude that the model is robust with regards to the chosen time period but...
447

Vícerozměrná kredibilita / Multidimensional Credibility

Zhuravova, Nadezda January 2014 (has links)
The aim of this graduation work is theoretically describe and also demonstrate the practical application of the theory of credibility in the multidimensional case. This theory is one of the most frequently used methods for calculating premiums, expected claims frequency or the expected average amount of damage. In this work we describe multidimensional Bühlmann-Straub credibility model and two- dimensional model with a known distribution. For each of these models we derive credibility estimate and examples of using these estimates in practice. Both models are compared on simulated data. Powered by TCPDF (www.tcpdf.org)
448

Dynamické modely zemětřesného zdroje a seismicita / Dynamic models of earthquake source and modeling of seismicity

Kostka, Filip January 2015 (has links)
In the present thesis we perform modeling of earthquake source using laboratory derive rate-and-state laws of friction. We have developed a code in Fortran 90 for modeling a planar, two-dimensional fault with general dip and heterogeneous distribution of frictional parameters. We use a quasi-dynamic approximation and assume that the fault is submnerged in an infinite elastic half-space. We performed an extensive number of numerical experiments to study the effect of fricitonal parameters distribution on the spatio-temporal complexity of slip on fault. We also study the effect of the so called Coulomb stress changed on clock advance and clock delay of events. For this purpose we use both a homogeneous model and a model of random frictional parameteres which exhibits the Gutenberg-Richter frequency- size dependence in the range of two magnitudes. We find that the effect of Couloumb stress change is nontrivial and depends on factors such as the domain of stress load and the slip velocity on it. Powered by TCPDF (www.tcpdf.org)
449

Food safety impacts on U.S. domestic meat demand and international red meat trade

Shang, Xia January 1900 (has links)
Doctor of Philosophy / Department of Agricultural Economics / Glynn Tonsor / Few things facing the U.S. meat industry in recent years have garnered more attention of economic researchers than food safety events, policies, and mitigation efforts. This dissertation has two main essays and themes focusing on both domestic and international food safety issues. Contributing new insights to this situation, the impacts of FSIS (Food Safety Inspection Service) recalls on consumer meat demand in the United States are estimated by a series of Rotterdam models in the first study using monthly grocery-scanner data. Multiple model specifications are employed to further assess effects across meat products and geographic regions. Recall variables are constructed separately as beef E. coli recall, beef non-E. coli recall, pork recall, and poultry recall variables to facilitate finer assessment of demand impacts. Results suggest beef E. coli recalls significantly reduce the demand for ground beef contemporaneously among most, but not all, regions in the United States. The ultimate finding of food safety effects neither being fully homogeneous nor entirely heterogeneous warrants appreciation. In order to protect domestic consumers and meat industries from potential food safety hazards, some member countries of the WTO implement sanitary and phytosanitary (SPS) measures as non-tariff barriers. The second study focuses on investigating the determinants of red meat trade patterns and associated impacts of SPS regulations. This analysis uses multiple product-level gravity equation models and PPML (Poisson Pesudo Maximum-likelihood estimators to overcome sample selection bias and heteroscedasticity and examine the trade relationship among other factors. Results indicate that, trade values of frozen beef and pork are significantly reduced by the implementation of SPS measures. Also, the spillover effects across meat products on trade were detected which provides essential information to the meat industry, policy makers, and trade representatives.
450

Scalable and Robust Designs of Model - Based Control Strategies for Energy - Efficient Buildings

Agbi, Clarence 01 May 2014 (has links)
In the wake of rising energy costs, there is a critical need for sustainable energy management of commercial and residential buildings. Buildings consume approximately 40% of total energy consumed in the US, and current methods to reduce this level of consumption include energy monitoring, smart sensing, and advanced integrated building control. However, the building industry has been slow to replace current PID and rule-based control strategies with more advanced strategies such as model-based building control. This is largely due to the additional cost of accurately modeling the dynamics of the building and the general uncertainty that model-based controllers can be reliably used in real conditions. The first half of this thesis addresses the challenge of constructing accurate grey-box building models for control using model identification. Current identification methods poorly estimate building model parameters because of the complexity of the building model structure, and fail to do so quickly because these methods are not scalable for large buildings. Therefore, we introduce the notion of parameter identifiability to determine those parameters in the building model that may not be accurately estimated and we use this information to strategically improve the identifiability of the building model. Finally, we present a decentralized identification scheme to reduce the computational effort and time needed to identify large buildings. The second half of this thesis discusses the challenge of using uncertain building models to reliably control building temperature. Under real conditions, building models may not match the dynamics of the building, which directly causes increased building energy consumption and poor thermal comfort. To reduce the impact of model uncertainty on building control, we pose the model-based building control problem as a robust control problem using well-known H1 control methods. Furthermore, we introduce a tuning law to reduce the conservativeness of a robust building control strategy in the presence of high model uncertainty, both in a centralized and decentralized building control framework.

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