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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.
41

Motyvacinių faktorių įtaka personalo kaitai UAB „Drogas“ / The job motivation factors influence over the fluctuation to manpower of UAB „Drogas“

Žakaitienė, Romualda 26 September 2008 (has links)
Norėdami išvengti nuolatinės darbuotojų kaitos, įmonių vadovai privalo išsiaiškinti, kokie motyvaciniai faktoriai labiausiai skatina darbuotojus palikti organizaciją. Tyrimo metu, įvertinus motyvacinių faktorių grupių pagrindinius trūkumus ir atlikus darbuotojų kaitą skatinančių motyvacinių faktorių analizę UAB „Drogas“, nustatyta, jog svarbiausios įmonės darbuotojų motyvavimo sistemos problemos yra nepakankamas gaunamo darbo užmokesčio lygis, galimybė kelti kvalifikaciją, nepakankamas papildomos skatinimo sistemos buvimas įmonėje ir nepatenkinami santykiai su vadovybe. Siekiant išspręsti šias darbuotojų skatinimo problemas įmonės vadovybė turi pasirinkti optimaliausius įmonės darbuotojų valdymo metodus, atsižvelgiant į darbuotojų materialinius ir moralinius poreikius bei individualias jų savybes. / The main purpose of managers to avoid of constantly infuence over the fluctuation to manpower is to find out what the main motivation factors has influence on the employees decision to leave the organization. During the research, upon evaluation of main weakness of groups of motivation factors and upon accomplishment of analysis of factors infuence over the fluctuation to manpower of UAB „Drogas“, it was determined that the main problems of the system of employees motivation are insufficient level of available wages, insufficient possibilities to raise qualification, insufficient additional motivation system in the enterprise and not satisfied relations with management of the enterprise. In order to solve the problems of stimulation of employees, the management of the enterprise has to choose the most optimal methods of management of employees, considering material and moral needs of the employees and individual their characteristics.
42

Compression en phase et en quadrature dans le bruit de grenaille d'une jonction tunnel

Gasse, Gabriel January 2014 (has links)
L'??tude fine des fluctuations de courant dans les petites composantes ??lectroniques est un excellent moyen de tester notre compr??hension du transport ??lectronique quantique. Lorsque la fr??quence est suffisamment ??lev??e, ce qui est mesur?? en laboratoire n???est plus un courant d?????lectrons mais un champ ??lectromagn??tique caus?? par l???agitation des ??lectrons. Faire un pont entre l???optique en terme de photons et l?????lectronique quantique est l???objectif dans le laboratoire de Bertrand Reulet. Ce m??moire de ma??trise traite des fluctuations de courant d???une jonction tunnel polaris??e en courant et excit??e avec une tension alternative dans les micro-ondes. La nouveaut?? dans ce projet provient du fait que les fluctuations de courant g??n??r??es par la jonction tunnel ont ??t?? mesur??es en phase et en quadrature avec l???excitation micro-onde envoy??e sur l?????chantillon. Il a ??t?? d??montr?? qu???il est possible de faire un parall??le entre les fluctuations du courant ??lectrique et l???optique quantique pour arriver ?? pr??dire le comportement de ces fluctuations en phase et en quadrature. De plus, la pr??sence d?????tat comprim?? ou ??squeez???? sur l???une des quadratures du courant a ??t?? mesur??e exp??rimentalement. Les r??sultats obtenus sont en parfait accord avec la th??orie d??velopp??e.
43

Etude du comportement dynamique et du transfert de matière et de chaleur entre des particules sphériques et un écoulement laminaire ou turbulent

Belkhelfa, Yazid 02 July 2008 (has links) (PDF)
A caractérisation de l'écoulement, du transfert de chaleur et de masse lors du déplacement de gouttelettes de diamètre inferieur au millimètre dans un milieu extérieur font l'objet de notre étude. La première partie présente l'état de l'art des connaissances théoriques et expérimentales des comportements aérodynamiques ainsi que les mécanismes de transfert thermiques et massiques intervenant entre une phase dispersée et une phase continue. La deuxième partie est consacrée à l'étude du phénomène d'évaporation d'une gouttelette mono-dispersée en chute libre dans l'air. Pour cela, nous avons réalisé un dispositif expérimental. Les mesures, nous permettent de prédire l'évaporation de la gouttelette en fonction des caractéristiques physico-chimiques et de l'hygrométrie du milieu extérieur. Pour la modélisation du transfert de chaleur et de masse nous avons utilisé un modèle simple qui tient en compte du couplage entre le mouvement et les phénomènes de transferts, validé dans une précédente étude au sein du laboratoire. Un bon accord est observé. La troisième partie traite de la simulation numérique de l'interaction entre les particules sphériques dans un régime laminaire. Tout d'abord, nous avons proposé et validé un modèle simple qui ne tient pas en compte des phénomènes d'interaction. Les résultats obtenus sont en concordance avec la littérature. Par la suite, nous avons étudié l'interaction entre trois particules identiques et co-alignées. Ce modèle tient compte de la nature de la particule, du nombre du Reynolds et de la distance de séparation. Nous avons validé ce travail par une comparaison avec une étude précédente que nous avons généralisé. La dernière partie est cernée sur l'étude de la dispersion des gouttelettes dans un écoulement turbulent homogène et isotrope. Pour cela, nous avons proposé un modèle Lagrangien de suivi des trajectoires. La production de la turbulence est assurée par une condition de turbulence de grille. Nous avons considéré que les caractéristiques moyennes de l'écoulement fluide sont connues. La sélection des fluctuations de vitesse turbulente est assurée par une méthode probabiliste gaussienne que nous avons développée. La fluctuation est conservée durant un certain temps lié à turbulence, elle est renouvelée au cours du calcul. Ce renouvellement est donné par le temps caractéristique de turbulence.
44

Thermal measurement of turbulent wall shear stress fluctuations: tackling the effects of substrate heat conduction.

Assadian, Elsa 27 April 2012 (has links)
This thesis presents a computational analysis of multi-element guard-heated sensors designed to overcome the most severe limitation of conventional thermal sensors for wall shear stress (WSS) measurement in turbulent flows –that of indirect heat conduction through the substrate. The objectives of this thesis are the study of guard-heated sensors {i} to quantify the reduction, over conventional single-element sensors, of substrate heat conduction losses and resultant errors over a range of applied shear and {ii} to examine a range of values of guard heater geometric parameters, in two common fluids, air and water and identify the best designs. Wall-turbulence, the turbulent flow in the vicinity of solid boundaries, has proved difficult to model accurately, due to the lack of accurate WSS measurements. Examples of areas of impact are drag force reduction on transport vehicles in land, sea, air, which today largely translate to reduced fossil fuel use and dependence; aerodynamic noise and control for flight and for wind energy conversion; atmospheric and oceanic transport studies for weather, climate and for pollutant transport; riverbank erosion. Constant-temperature anemometry with MEMS devices, flush-mounted hot-film thermal sensors, is non-intrusive, affords the best temporal resolution and is well-established. However, these hot-film probes suffer from unwanted heat transport to the fluid through the substrate, with errors and nonlinearity large enough to overwhelm quantitative utility of the data. Microfabrication techniques have enabled multi-element guard-heated prototypes to be fabricated. Our results show that errors in sensing-element signals, contributing to spectral distortion, are sensitive to sensor location within the guard heater. These errors can be reduced to below 1% of the signal with proper location of the sensor. Guard heating also reduces the large variation in spatial averaging due to substrate conduction. This makes them suitable for turbulent flows with a large range of fluctuations. / Graduate
45

ウェーブレット逆変換のアナロジーによるガスト応答波形の推定

北川, 徹哉, KITAGAWA, Tetsuya 04 1900 (has links)
No description available.
46

Aspects of work in quantum thermodynamics

Browne, Cormac January 2017 (has links)
Landauer's principle states that it costs at least k<sub>B</sub>T ln 2 of work to reset one bit in the presence of a heat bath at temperature T. The bound of k<sub>B</sub>T ln 2 is achieved in the unphysical infinite-time limit. Here we consider two different finite-time protocols - one with discretised time and the second in the continuous limit. We prove analytically that the discrete time protocol enables one to reset a bit with a work cost close to k<sub>B</sub>T ln 2 in a finite time. We construct an explicit protocol that achieves this, which involves thermalising and changing the system's Hamiltonian so as to avoid quantum coherences. Using concepts and techniques pertaining to single-shot statistical mechanics, we furthermore prove that the heat dissipated is exponentially close to the minimal amount possible not just on average, but guaranteed with high confidence in every run. Moreover we exploit the protocol to design a quantum heat engine that works near the Carnot efficiency in finite time. We further contrast this to a continuous time version of the protocol which is substantially less energy sufficient. We also consider the fluctuations in the work cost, and calculate how their magnitude is suppressed by a factor depending on the length of the protocol. We demonstrate with an experiment how molecules are a natural test-bed for probing fundamental quantum thermodynamics. Single-molecule spectroscopy has undergone transformative change in the past decade with the advent of techniques permitting individual molecules to be distinguished and probed. By considering the time-resolved emission spectrum of organic molecules as arising from quantum jumps between states, we demonstrate that the quantum Jarzynski equality is satisfied in this set-up. This relates the heat dissipated into the environment to the free energy difference between the initial and final state. We demonstrate also how utilizing the quantum Jarzynski equality allows for the detection of energy shifts within a molecule, beyond the relative shift.
47

Proposta e validação de uma nova metodologia para medição automatizada de folgas de trabalho em sistemas de direção automotiva

Aimi, Vinícius January 2010 (has links)
Todos os anos, milhões de reais são gastos para cobrir os custos de garantia de caixas de direção que apresentam problemas de ruído e inconvenientes são causados nas linhas de montagem das grandes montadoras devido a este mesmo problema. Parte destas ocorrências se devem a um ruído específico chamado de Rattle Noise originado por uma operação de regulagem incorreta do bujão de ajuste. Em caixas de direção cujo “design” não permite uma medição direta da regulagem do sistema de ajuste, não existe um meio de avaliar a qualidade da operação e garantir que todas as peças estejam dentro das especificações. Baseado neste problema, este trabalho visa propor uma metodologia de avaliação da qualidade da operação de ajuste da caixa de direção de uma maneira indireta, porém com uma representação muito próxima do resultado que seria apresentado por uma medição direta, se o “design” do produto permitisse. Para tornar isso possível, foram realizados ensaios com caixas de direção em uma bancada experimental de testes aplicando-se a cremalheira cargas perpendiculares a seu eixo e momentos torsores. Foram avaliadas as respostas da amplitude do movimento angular descrito e também do deslocamento da cremalheira no sentido do seu raio observando-se a correlação que as respostas tinham com a real folga do mancal no interior do sistema de ajuste. Estes ensaios mostram que existe uma correlação muito forte entre as variáveis medidas externamente e a real flutuação do mancal no interior do sistema de ajuste e, através da regressão linear, uma equação foi definida para expressar este correlacionamento. Uma máquina foi construída para que a verificação fosse feita em 100% dos mecanismos produzidos na linha de montagem de um modelo de caixa de direção. Depois de construída a máquina, validou-se o seu funcionamento através dos estudos de R&R (Repetitividade e Reprodutibilidade), que ficaram abaixo de 20%, e da calibração da mesma comparando-se os resultados fornecidos pela máquina com as leituras realizadas de forma direta através de peças com o “design” alterado de forma a tornar isto possível, mostrando uma correlação de 99%. Hoje, o sistema está rodando perfeitamente em uma linha de montagem de um grande fabricante de sistemas de direção nacional. / Every year, millions of dollars are spent to cover the insurance costs of steering systems that have noise problems and inconveniences are caused in assembly lines of major car industry because of this same problem. Most of these occurrences are due to a specific noise called Rattle Noise caused by an incorrect operation of the adjustment screw to adjust the steering box. In cases where the direction of "design" does not allow a direct measurement of the values of the adjustment system, there is no way to assess the quality of operation and thus ensure that all parts are within specifications. Based on this problem, this work proposes a methodology to assess the quality of the adjust operation of the steering system in an indirect way, but with a very close representation of the results to be presented by a direct measurement if the "product design" had allowed. To make this possible, tests on steering systems were conducted in a test bench each exciting to rack with loads perpendicular to its axis and torsion loads. We studied responses of the magnitude of angular momentum described by the system and also the displacement of the rack along its radius by observing the correlation within the measured values to the actual bearing clearance into the system. These tests showed that there was a very strong correlation between the measured variables and externally real bearing fluctuation within the system of adjustment and using a linear regression, an equation was defined to express this correlation. A machine was built in order to verify 100% of the products in the assembly line of a vehicle steering system. Once built the machine and validated its operation through R & R studies, which has shown results below of 20%, the system was calibrated comparing the output of the machine with the readings taken directly in parts with the altered "design" to make this possible, showing a correlation of 99%. Today, the system is running perfectly on an assembly line of a major national manufacturer of steering systems.
48

Proposta e validação de uma nova metodologia para medição automatizada de folgas de trabalho em sistemas de direção automotiva

Aimi, Vinícius January 2010 (has links)
Todos os anos, milhões de reais são gastos para cobrir os custos de garantia de caixas de direção que apresentam problemas de ruído e inconvenientes são causados nas linhas de montagem das grandes montadoras devido a este mesmo problema. Parte destas ocorrências se devem a um ruído específico chamado de Rattle Noise originado por uma operação de regulagem incorreta do bujão de ajuste. Em caixas de direção cujo “design” não permite uma medição direta da regulagem do sistema de ajuste, não existe um meio de avaliar a qualidade da operação e garantir que todas as peças estejam dentro das especificações. Baseado neste problema, este trabalho visa propor uma metodologia de avaliação da qualidade da operação de ajuste da caixa de direção de uma maneira indireta, porém com uma representação muito próxima do resultado que seria apresentado por uma medição direta, se o “design” do produto permitisse. Para tornar isso possível, foram realizados ensaios com caixas de direção em uma bancada experimental de testes aplicando-se a cremalheira cargas perpendiculares a seu eixo e momentos torsores. Foram avaliadas as respostas da amplitude do movimento angular descrito e também do deslocamento da cremalheira no sentido do seu raio observando-se a correlação que as respostas tinham com a real folga do mancal no interior do sistema de ajuste. Estes ensaios mostram que existe uma correlação muito forte entre as variáveis medidas externamente e a real flutuação do mancal no interior do sistema de ajuste e, através da regressão linear, uma equação foi definida para expressar este correlacionamento. Uma máquina foi construída para que a verificação fosse feita em 100% dos mecanismos produzidos na linha de montagem de um modelo de caixa de direção. Depois de construída a máquina, validou-se o seu funcionamento através dos estudos de R&R (Repetitividade e Reprodutibilidade), que ficaram abaixo de 20%, e da calibração da mesma comparando-se os resultados fornecidos pela máquina com as leituras realizadas de forma direta através de peças com o “design” alterado de forma a tornar isto possível, mostrando uma correlação de 99%. Hoje, o sistema está rodando perfeitamente em uma linha de montagem de um grande fabricante de sistemas de direção nacional. / Every year, millions of dollars are spent to cover the insurance costs of steering systems that have noise problems and inconveniences are caused in assembly lines of major car industry because of this same problem. Most of these occurrences are due to a specific noise called Rattle Noise caused by an incorrect operation of the adjustment screw to adjust the steering box. In cases where the direction of "design" does not allow a direct measurement of the values of the adjustment system, there is no way to assess the quality of operation and thus ensure that all parts are within specifications. Based on this problem, this work proposes a methodology to assess the quality of the adjust operation of the steering system in an indirect way, but with a very close representation of the results to be presented by a direct measurement if the "product design" had allowed. To make this possible, tests on steering systems were conducted in a test bench each exciting to rack with loads perpendicular to its axis and torsion loads. We studied responses of the magnitude of angular momentum described by the system and also the displacement of the rack along its radius by observing the correlation within the measured values to the actual bearing clearance into the system. These tests showed that there was a very strong correlation between the measured variables and externally real bearing fluctuation within the system of adjustment and using a linear regression, an equation was defined to express this correlation. A machine was built in order to verify 100% of the products in the assembly line of a vehicle steering system. Once built the machine and validated its operation through R & R studies, which has shown results below of 20%, the system was calibrated comparing the output of the machine with the readings taken directly in parts with the altered "design" to make this possible, showing a correlation of 99%. Today, the system is running perfectly on an assembly line of a major national manufacturer of steering systems.
49

Utilização do dentreded fluctuation analysis e do dentreded cross-correlation analysis para estudo do espectro de correlação de ações constantes no Ibovespa no período de crise do subprime / Use of dentreded fluctuation analysis and dentreded cross-correlation analysis for study of the correlation spectrum of constant actions in the Ibovespa in the subprime crisis period

Silva, Diego Roberto Cintra da [UNESP] 02 December 2016 (has links)
Submitted by Diego Roberto Cintra da Silva null (diegocntr@hotmail.com) on 2017-01-22T14:31:57Z No. of bitstreams: 1 Diego Cintra - Dissertação - Mestrado.pdf: 3332491 bytes, checksum: cb4ba5462d138f7b73df3323acd794c3 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-01-25T16:43:04Z (GMT) No. of bitstreams: 1 silva_drc_me_bauru.pdf: 3332491 bytes, checksum: cb4ba5462d138f7b73df3323acd794c3 (MD5) / Made available in DSpace on 2017-01-25T16:43:04Z (GMT). No. of bitstreams: 1 silva_drc_me_bauru.pdf: 3332491 bytes, checksum: cb4ba5462d138f7b73df3323acd794c3 (MD5) Previous issue date: 2016-12-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As crises que ocorrem no mercado de ações são prejudiciais não só à parte monetária da economia de um país, mas ao desenvolvimento do país como um todo. A crise do subprime em 2008, que se iniciou nos Estados Unidos da América, atingiu o mundo todo, muitos países tiveram quedas significativas do PIB e vários entraram em recessão. Existe, então, o interesse em se compreender a dinâmica das séries temporais de variáveis como retorno e volatilidade das ações negociadas nesse mercado, a fim de compreender as diferenças de seu comportamento em momentos de crise econômica. Com o objetivo de analisar o espectro de correlação da volatilidade de ações no período da crise de 2008 e em suas vizinhanças, foram verificadas 31 ações de empresas pertencentes a diversos setores da economia brasileira, que compuseram entre 2007 e 2011 o Índice Bovespa. Para tal foram utilizados os métodos do Detrended Fluctuation Analisys – DFA e do Detrended Cross-Correlation Analisys – DCCA. Ambos métodos evidenciaram uma significativa mudança na função de probabilidade no período de crise comparativamente aos períodos de sua vizinhança. / Crises occurring in the stock market are harmful not only to the monetary part of a country's economy, but to the development of the country as a whole. The subprime crisis in 2008, which began in the United States of America, hit the whole world, many countries had significant declines in GDP and several went into recession. There is, therefore, an interest in understanding the dynamics of time series of variables such as return and volatility of the shares traded in this market, in order to understand the differences in their behavior in times of economic crisis. With the objective of analyzing the correlation spectrum of stock volatility in the period of the 2008 crisis and its neighborhoods, 31 stocks of companies belonging to various sectors of the Brazilian economy were verified, which made up the Bovespa Index between 2007 and 2011. The methods of Detrended Fluctuation Analyzes - DFA and Detrended Cross-Correlation Analyzes - DCCA were used for this. Both methods evidenced a significant change in the probability function in the period of crisis compared to the periods of its neighborhood.
50

Důvody fluktuace sester z nemocnic / The reasons for Turnover of Nurses Working in Hospital

BÁRTOVÁ, Marie January 2010 (has links)
In my diploma thesis I deal with the reasons for turnover of nurses working in hospitals. Health care workers turnover is a topical issue. It is therefore desirable to pay attention to this issue, to focus on identification of its causes and explore the motivations that lead nurses to leave their jobs. Only when we know the causes, it is possible to start fighting against turnover and to introduce measures for its reduction. The aim of the thesis was to identify causes of turnover of nurses in selected hospitals of the South Bohemian region, to survey the current state of turnover of nurses in selected hospitals of the South Bohemian region, and to identify measures imposed by the management in selected hospitals of the South Bohemian region to affect the excessive turnover of nurses. The goals of the thesis were met. Based on interviews conducted with nurses who had left their workplaces, hypotheses of this thesis were stated. These are the following hypotheses: H: 1 One of the main causes of nurse turnover is the psychically demanding job, H: 2 One of the main causes of nurse turnover is the physically demanding work of nurses, H: 3 Nurses change jobs due to problematic interpersonal relationships, H: 4 Nurses change jobs because of increasing demands for nursing competencies, H: 5 Younger nurses change jobs more frequently than older nurses, H: 6 Younger nurses change jobs because they cannot ensure care for their children when pursuing their profession, H: 7 Nurse turnover rates are uniform over all departments in selected hospitals in the South Bohemian region, and H: 8 Management of selected hospitals in the South Bohemian region implements measures to affect the excessive turnover of nurses. To verify the established hypotheses, quantitative research through a questionnaire survey was conducted in selected hospitals in the South Bohemian region. Furthermore, the interviews with the Deputy Director of Nursing in individual hospitals of the South Bohemian region were carried out. The research outcomes show that hypothesis H: 1 One of the main causes of nurse turnover is the psychically demanding job, H: 2 One of the main causes of turnover of nurse is the physically demanding work of nurses, H: 3 Nurses change jobs due to problematic interpersonal relationships, H: 5 Younger nurses change jobs more frequently than older nurses, and H: 7 Nurse turnover rates are uniform over all departments in selected hospitals in South Bohemian region, were confirmed. However, the research survey proved that H 4: Nurses change jobs because of increasing demands for nursing competencies, and H: 6 Younger nurses change jobs because they cannot ensure care for their children when pursuing their profession, cannot be uniquely confirmed. Hypothesis H: 8 Management of selected hospitals in the South Bohemian region implements measures to affect the excessive turnover of nurses was disproved by my research.

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