• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 26
  • 22
  • 10
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 77
  • 17
  • 9
  • 8
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 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.
71

兩個組合數學的主題: Hadamard 矩陣的建構及有關森林的研究 / Two Combinatorial Topics: Constructions of Hadamard Matrices and Studies of Forests

施耀振, Shih,Yaio-Zhern Unknown Date (has links)
在這篇論文,我們主要探討兩個獨立的組合數學主題:一個是Hadamard矩陣的建構,一個是有關森林的研究。在第一個主題,所得者又分為二,其一,我們從一個已知的Hadamard矩陣,利用Sylvester的方法去建構名為Jm-Hadamard矩陣。從這個矩陣裡,藉由在Sm上適當的排列,可以獲致其他2mm!-1個Hadamard矩陣。另外,我們引進Jm-class的概念, 將之寫成CJm,並探討當n整除n'時,CJn'是否包含於CJn。關於這個問題,我們得到最初的結論是CJ8 CJ4 CJ2。其二,在已知的t個階數分別是4m1,4m2,…,4mt的Hadamard矩陣,希望獲得一個階數是2km1m2… mt的Hadamard矩陣,使得k值愈小愈好。我們可以找到最小指數的上界,這個數稍好於Craigen及de Launey所得到的值。在第二個主題裡,我們致力於三個目標,首先,我們將平面樹上的一些結果,推廣到平面森林上,諸如Shapiro的結果,葉子的偶數、奇數問題,Catalan數與類似數之間的恒等式。其二,我們用了一個很簡潔的方法去證明Chung-Feller定理,也獲致相關的結果及應用。最後,我們以研究數種n-caterpillars的優美標法,作為本文的結束,最特別的是我們可藉用拉丁方陣去建構2n-caterpillars的優美標法。
72

Präzisionsmassebestimmung einzelner Partikel im Femtogrammbereich und Anwendungen in der Oberflächenphysik

Illemann, Jens 03 August 2000 (has links) (PDF)
In this work, a new method for mass determination of single low-charged particles in the sub-picogram regime is developed. It opens applications to chemical physics and surface science via determination of growth rates. The method combines the well-known electrodynamic quadrupole ion trap in a UHV-chamber and fourier transformation of scattered light. The achieved mass resolution of down to $10^{-4}$ at 100 fg mass on a time scale of ten seconds allows a resolution of a few percent of the mass of an adsorbed monolayer and to determine growth rates down to one molecule per second on a time scale of one day. The observation of temperature dependent sticking coefficients results in the measures of the energy of an adsorption barrier. Observation of discrete steps in the rate gives information about the density of molecules in an ordered layer. Temperature dependent desorption data gives the binding energy. The dependence of these observables on the controllable curvature and charge of the substrate's surface is measurable. The first part of this dissertation consists of a description of the common theory of the quadrupole ion trap with the completion of not widely known, newly introduced, contributions to the trapping potential. These contributions lead to systematic shifts in the mass determination. In particular the influence of the inhomogenity of the electrical field, that is used for compensating the gravitational force, is investigated analytically and corroborated experimentally. It is assumed, that the particle's finite size effects in a further shift. In the experimental part initial demonstrative measurements are presented: the time-resolved adsorption of fullerene, anthracene and NO on silica spheres with 500nm diameter has been measured at room temperature. In addition the secondary electron yield of in-situ prepared particles during irradiation with monoenergetic electrons has been determined by analyzing the distribution of change of the number of elementary charges by single events of charging.
73

A relativizaçao da impenhorabilidade dos bens de familia para a satisfaçao de créditos trabalhistas.

Oliveira, Vanessa Lima Bacilieri de January 2010 (has links)
Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2013-04-17T19:27:45Z No. of bitstreams: 1 VOliveira.pdf: 989857 bytes, checksum: 8067986511c12bf701bca81aaf2b3e8c (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-05-09T18:09:48Z (GMT) No. of bitstreams: 1 VOliveira.pdf: 989857 bytes, checksum: 8067986511c12bf701bca81aaf2b3e8c (MD5) / Made available in DSpace on 2013-05-09T18:09:49Z (GMT). No. of bitstreams: 1 VOliveira.pdf: 989857 bytes, checksum: 8067986511c12bf701bca81aaf2b3e8c (MD5) Previous issue date: 2010 / Com o fim de propiciar uma mudança na mentalidade dos operadores do direito visando tornar mais efetivo o processo bem como respeitando os princípios norteadores do nosso ordenamento jurídico e principalmente a pessoa do trabalhador face a sua hipossuficiência o presente trabalho tem por objetivo estudar a satisfação de créditos trabalhistas através da possibilidade de penhora de determinados bens considerados como de família. A partir de uma noção histórica do nascimento do direito do trabalho com enfoque posterior à sua evolução e desenvolvimento no Brasil será traçado o conceito deste ramo jurídico especilizado bem como alguns dos seus princípios específicos norteadores mais precisamente o princípio da proteção do trabalhador e da valorização do trabalho. Posteriormente tentar-se-á definir o conceito de bens de família a partir do estudo dos mesmos através da análise do princípio da dignidade da pessoa humana, direito à moradia utilidade e habitalidade para fins de delimitação da impenhorabilidade desses bens. Ultrapassando tal estudo será objeto de análise também o princípio da efetividade processual como fundamento do processo assim como a execução trabalhista a qual face à natureza alimentar do crédito exeqüendo, deve ser ainda mais efetiva e célere. Ulteriormente serão abordados os princípios da razoabilidade e da proporcionalidade, os quais se tornam imprescindíveis ao alcance de uma interpretação justa e eficaz no que tange à proteção insculpida na Lei 8.009/90. Por fim após fixarem-se as premissas necessárias à viabilização da interpretação mais adequada das normas postas sob apreço no presente passa-se a propor a relativização da impenhorabilidade dos bens de família para a satisfação de créditos trabalhistas através de parâmetros de razoabilidade e proporcionalidade na ponderação de valores conflitantes. / Salvador
74

Strategie rozvoje podniku / Strategy of Business Development

Nováková, Libuše January 2021 (has links)
This thesis is aimed at business plan of further development of the company XY, s.r.o. The theoretical basis for the work include basic concepts related to the focusing on the main idea of the company´s development plan. The analysis section deals with the evaluation of the current problém and includes the identification of key factors in the wider context of the environment, the summary of which is then followed by a suitable strategy for the implementation of future development. In this part, analyzes of External and internal factors are used. The proposals are based on a performer SWOT analysis. This section lists appropriate measures to eliminate risks in the field.
75

Präzisionsmassebestimmung einzelner Partikel im Femtogrammbereich und Anwendungen in der Oberflächenphysik

Illemann, Jens 26 July 2000 (has links)
In this work, a new method for mass determination of single low-charged particles in the sub-picogram regime is developed. It opens applications to chemical physics and surface science via determination of growth rates. The method combines the well-known electrodynamic quadrupole ion trap in a UHV-chamber and fourier transformation of scattered light. The achieved mass resolution of down to $10^{-4}$ at 100 fg mass on a time scale of ten seconds allows a resolution of a few percent of the mass of an adsorbed monolayer and to determine growth rates down to one molecule per second on a time scale of one day. The observation of temperature dependent sticking coefficients results in the measures of the energy of an adsorption barrier. Observation of discrete steps in the rate gives information about the density of molecules in an ordered layer. Temperature dependent desorption data gives the binding energy. The dependence of these observables on the controllable curvature and charge of the substrate's surface is measurable. The first part of this dissertation consists of a description of the common theory of the quadrupole ion trap with the completion of not widely known, newly introduced, contributions to the trapping potential. These contributions lead to systematic shifts in the mass determination. In particular the influence of the inhomogenity of the electrical field, that is used for compensating the gravitational force, is investigated analytically and corroborated experimentally. It is assumed, that the particle's finite size effects in a further shift. In the experimental part initial demonstrative measurements are presented: the time-resolved adsorption of fullerene, anthracene and NO on silica spheres with 500nm diameter has been measured at room temperature. In addition the secondary electron yield of in-situ prepared particles during irradiation with monoenergetic electrons has been determined by analyzing the distribution of change of the number of elementary charges by single events of charging.
76

Estimating the load weight of freight trains using machine learning

Kongpachith, Erik January 2023 (has links)
Accurate estimation of the load weight of freight trains is crucial for ensuring safe, efficient and sustainable rail freight transports. Traditional methods for estimating load weight often suffer from limitations in accuracy and efficiency. In recent years, machine learning algorithms have gained significant attention and use cases within the railway industry due to their strong predictive capabilities for classification and regression tasks. This study aims to present a proof of concept in the form of a comparative analysis of five machine learning regression algorithms: Polynomial Regression, K-Nearest Neighbors, Regression Trees, Random Forest Regression, and Support Vector Regression for estimating the load weight of freight trains using simulation data. The study utilizes two comprehensive datasets derived from train simulations in GENSYS, a simulation software for modeling rail vehicles. The datasets encompasses various driving condition factors such as train speed, track conditions and running gear configurations. The algorithms are trained and evaluated on these datasets and their performance is evaluated based on the root mean squared error and R2 metrics. Results from the experiments demonstrate that all five machine learning algorithms show promising performance for estimating the load weight. Polynomial regression achieves the best result for both of the datasets when using many features of the datasets are considered. Random forest regression achieves the best result for both of the data sets when a small number features of the datasets are considered. Furthermore, it is suggested that the methodical approach of this study is examined on real world data from operating freight trains to assert the proof of concept in a real world setting. / Noggrann uppskattning av godstågens lastvikt är avgörande för att säkerställa säkra, effektiva och hållbara godstransporter via järnväg. Traditionella metoder för att uppskatta lastvikt lider ofta av begränsningar i noggrannhet och effektivitet. Under de senaste åren har maskininlärningsalgoritmer fått betydande uppmärksamhet och användningsfall inom järnvägsindustrin på grund av deras starka prediktiva förmåga för klassificerings- och regressionsproblem. Denna studie syftar till att presentera en proof of concept i form av en jämförande analys av fem maskininlärningalgoritmer för regression: Polynom regression, K-Nearest Neighbors, Regression träd, Random Forest Regression och Support Vector Regression för att uppskatta lastvikten för godståg med hjälp av simuleringsdata. Studien använder två omfattande dataset konstruerade från tågsimuleringar i GENSYS, en simuleringsprogramvara för modellering av järnvägsfordon. Dataseten omfattar olika körfaktorer såsom tåghastighet, spårförhållanden och vagns konfigurationer. Algoritmerna tränas och utvärderas på dessa dataset och deras prestanda utvärderas baserat på root mean squared error och R2 måtten. Resultat från experimenten visar att alla fem maskininlärningsalgoritmerna visar lovande prestanda för att uppskatta lastvikten. Polynom regression uppnår det bästa resultatet för båda dataset när många variabler i datan beaktas. Random Forest Regression ger det bästa resultatet för båda dataset när ett mindre antal variabler i datan beaktas. Det föreslås det att det metodiska tillvägagångssättet för denna studie undersöks på verklig data från aktiva godståg för att fastställa en proof of concept på en verklig världsbild.
77

Evapotranspiração e coeficientes de cultivo (KC) da cana-de-açúcar irrigada por gotejamento subsuperficial / Evapotranspiration and crop coefficients of subsurface drip irrigated sugar cane

Gonçalves, Fabricio Mota January 2010 (has links)
GONÇALVES, Fabrício Mota. Evapotranspiração e coeficientes de cultivo (KC) da cana-de-açúcar irrigada por gotejamento subsuperficial. 2010. 64 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia Agrícola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2010. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-28T16:59:16Z No. of bitstreams: 1 2010_dis_fmgonçalves.pdf: 3900094 bytes, checksum: 1ad79acf1432c0de09bcbdf52cb0f8c3 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-06-28T16:59:48Z (GMT) No. of bitstreams: 1 2010_dis_fmgonçalves.pdf: 3900094 bytes, checksum: 1ad79acf1432c0de09bcbdf52cb0f8c3 (MD5) / Made available in DSpace on 2016-06-28T16:59:48Z (GMT). No. of bitstreams: 1 2010_dis_fmgonçalves.pdf: 3900094 bytes, checksum: 1ad79acf1432c0de09bcbdf52cb0f8c3 (MD5) Previous issue date: 2010 / Sugar cane is one of the crops with the highest level of water consumption, with a high evapotranspiration demand throughout most of its cycle. Knowledge of the sugar cane water demand, the time that irrigation should be applied, and how to irrigate the crop are becoming increasingly important for the sustainable development of irrigated sugar cane cultivation, especially in areas of low water availability, as it is the case in northea stern Brazil. The experiment was carried out at the Curu Experimental Field (property of the Embrapa Tropical Agroindustry), located in the Curu-Paraipaba Irrig ation Project, city of Paraipaba-CE (3 ° 29 '20''S, 39 ° 9' 45''W and elevation 30m), in order to determine the evapotrans piration and crop coefficients (Kc) of sugarcane (Saccharum L. officinarium), subsurface drip-irrigated. It was used the SP 6949 sugar cane variety, planted in a spacing of 1.8 m between double rows and 0.4 m between rows within the double row. As to t he irrigation, we used one lateral water line for each double row, buried at a depth of 0.15 m, w ith self-compensating drip emitters, with a flow rate of 1 L h-1, spaced 0.5 m on the water line. The crop was irrigated daily and there were three fertigations per week. The irrigation de pth was periodically adjusted, keeping the soil water potential between -8 kPa to -20 kPa. The crop evapotranspiration (ETc) was determined using a wei ghing lysimeter with a surface area of 2.25 m 2. The reference evapotranspiration (ETo) was estimated by the FAO Penman-Monteith method. The durations of the phenological stages of cane sugar were estimated through analysis of soil cover, with the use of digital images. Durations of 31, 49, 237 and 118 days were observed, respectively for initial, crop development, mid-season and late season stages. The yields achieved within and outside the lysimeter were respectively 144.4 and 108.8 t ha -1 . The total ETc observed during the cycle of the sugar cane was 1074.1 m m, with maximum values of 6.6 mm d-1 during the mid-season stage. Observed Kc values for initial, mid-season and late season stages were respectively 0.23, 1 .03 and 0.50. In the crop development stage, the relationship between Kc and the (crop) soil cover was represented with good accuracy by a negative quadratic model. / A cana-de-açúcar é uma das culturas com maior consumo de água, apresentando uma alta demanda evapotranspirativa ao longo da maior parte do seu ciclo. O conhecimento das necessidades hídricas da cana-de-açúcar, do momento de aplicação da água requerida pela mesma e a forma de aplicação torna-se cada vez mais importante para o desenvolvimento sustentável da sua produção irrigada, principalmente em regiões de pouca disponibilidade hídrica, como é o caso da região Nordeste do Brasil. O experimento foi conduzido no Campo Experimental do Curu, pertencente à Embrapa Agroindústria Tropical localizado no Perímetro Irrigado Curu-Paraipaba, município de Paraipaba-CE (3° 29’ 20’’ S, 39° 9’ 45’’ W e altitude de 30 m), com o objetivo de determinar a evapotranspiração e os coeficientes de cultivo (Kc) da cana-de-açúcar (Saccharum officinarium L.), irrigada por gotejamento subsuperficial. Utilizou-se a variedade de cana SP 6949, plantada no espaçamento de 1,8 m entre fileiras duplas e 0,4 m entre linhas dentro da fileira dupla. Na irrigação utilizou-se uma linha lateral para cada fileira dupla, enterrada na profundidade de 0,15 m, com gotejadores autocompensantes, com vazão de 1 L h-1, espaçados de 0,5 m na linha. A cultura foi irrigada com freqüência diária e foram realizadas três fertirrigações por semana. A lâmina de irrigação foi ajustada periodicamente, mantendo-se o potencial de água no solo entre -8 kPa e -20 kPa. A evapotranspiração da cultura (ETc) foi determinada utilizando-se um lisímetro de pesagem com área superficial de 2,25 m2. A evapotranspiração de referência (ETo) foi estimada pelo método FAO Penman-Monteith. As durações das fases fenológicas da cana-de-açúcar foram estimadas por meio da análise da cobertura do solo pela cultura, determinada com o uso de imagens digitais. Foram observadas durações de 31, 49, 237 e 118 dias, para as fases inicial, de desenvolvimento, intermediária e final, respectivamente. A produtividade alcançada dentro e fora do lisímetro foi de 144,4 e 108,8 t ha-1, respectivamente. A ETc total observada durante o ciclo da cana-de-açúcar foi de 1.074,1 mm, com valores máximos da ordem de 6,6 mm d-1 durante a fase intermediária. Foram observados valores de Kc iguais a 0,23, 1,03 e 0,50, para as fases inicial, intermediária e final, respectivamente. Na fase de desenvolvimento vegetativo a relação entre o Kc e a cobertura do solo pela cultura foi representada com bastante exatidão por um modelo quadrático negativo.

Page generated in 0.0523 seconds