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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.
71

A Content Boosted Collaborative Filtering Approach For Movie Recommendation Based On Local &amp / Global Similarity And Missing Data Prediction

Ozbal, Gozde 01 September 2009 (has links) (PDF)
Recently, it has become more and more difficult for the existing web based systems to locate or retrieve any kind of relevant information, due to the rapid growth of the World Wide Web (WWW) in terms of the information space and the amount of the users in that space. However, in today&#039 / s world, many systems and approaches make it possible for the users to be guided by the recommendations that they provide about new items such as articles, news, books, music, and movies. However, a lot of traditional recommender systems result in failure when the data to be used throughout the recommendation process is sparse. In another sense, when there exists an inadequate number of items or users in the system, unsuccessful recommendations are produced. Within this thesis work, ReMovender, a web based movie recommendation system, which uses a content boosted collaborative filtering approach, will be presented. ReMovender combines the local/global similarity and missing data prediction v techniques in order to handle the previously mentioned sparseness problem effectively. Besides, by putting the content information of the movies into consideration during the item similarity calculations, the goal of making more successful and realistic predictions is achieved.
72

Exploring the authenticity of the tourist experience in culture heritage tourism in South Africa / Milena Ivanovic

Ivanovic, Milena January 2011 (has links)
The research question addressed by this dissertation is: How is the tourist experience formed and what constitutes the authenticity of the tourist experience for two market segments (motivated and not motivated by learning) of tourists visiting (political) cultural heritage sites in South Africa. The study explores the correlation between three types of authenticity, namely objective, constructed and existential on two independent tourist samples, motivated and not motivated by learning. This research was initiated for three reasons. The first reason forms part of the research problem; South African cultural experiences received the lowest ratings from the international tourists despite the fact that culture and heritage play a role in reimaging South Africa from Big 5 destination into ‘It’s possible’ and ‘Leave ordinary behind’. It was suspected that not all types of cultural heritage products justify such a low ratings, especially not the political cultural heritage sites South Africa is famous for. The second reason emerged from the academic literature on authenticity theories and calls from the influential group of postmodernist scholars to declare the objective authenticity obsolete and replace it with the existential authenticity. The argument that; the hyperreal nature of the postmodern experience and its detachment from reality makes the authenticity of the site redundant, seemed inapt for cultural heritage sites exclusively dependent on their historical and authentic values. The third reason was the inability of the postmodern paradigm to explain the new tourism phenomenon driven by the tourists search for selfdevelopment through authentic experiences. The new emerging paradigm, transmodernity seemed to offer better theoretical framework in explaining the omnivorouessness of tourists’ consumption and the authentic nature of tourist experiences. The correlational character of the research question required a descriptive correlational design and quantitative methodology. The selected research instrument for primary data collection is a self–administered questionnaire. The sampling strategy is a non–probability sampling, and the sampling method is a convenience or accidental sample. The data was collected from November 2010 to February 2011 at the Constitutional Hill National Heritage Site in Johannesburg. The final sample (436) consists of 254 foreign and 182 domestic tourists. The questionnaire was designed to identify the variables pertinent to each type of authenticity of tourists experience and of the resultant tourist experience. The data analysis provided very interesting results. Firstly, the results of crosstabulation proved that more than half (56%) of the tourists expressed strong agreement that the Constitution Hill provided them with authentic experience, hence a proof that political heritage sites are not responsible for the overall low experiential ratings of the country’s culture and heritage. Secondly, the results of the Spearman’s correlation coefficient proved that objective authenticity as an independent variable have strong positive correlation with constructed and existential authenticity hence a proof that objective authenticity cannot be declared obsolete and replaced with existential authenticity. Finally, the results of the t–test proved that motivation for learning and place of birth do not play an important role in how tourist evaluate and experience the authenticity of the site pointing to the omnivorous nature of tourist consumption. In line with the transmodern paradigm, motivation for learning plays a critical role in triggering the transformative, authentic experience distinctive of the existential authenticity. The results of the study also showed that 32% of tourists are in fact the purposeful, New Age, transmodern Cultural Creatives. Proposed theoretical model of authenticity of tourists experience presents a theoretical platform for future research studies. / Thesis (M.A. (Tourism))--North-West University, Potchefstroom Campus, 2012.
73

Exploring the authenticity of the tourist experience in culture heritage tourism in South Africa / Milena Ivanovic

Ivanovic, Milena January 2011 (has links)
The research question addressed by this dissertation is: How is the tourist experience formed and what constitutes the authenticity of the tourist experience for two market segments (motivated and not motivated by learning) of tourists visiting (political) cultural heritage sites in South Africa. The study explores the correlation between three types of authenticity, namely objective, constructed and existential on two independent tourist samples, motivated and not motivated by learning. This research was initiated for three reasons. The first reason forms part of the research problem; South African cultural experiences received the lowest ratings from the international tourists despite the fact that culture and heritage play a role in reimaging South Africa from Big 5 destination into ‘It’s possible’ and ‘Leave ordinary behind’. It was suspected that not all types of cultural heritage products justify such a low ratings, especially not the political cultural heritage sites South Africa is famous for. The second reason emerged from the academic literature on authenticity theories and calls from the influential group of postmodernist scholars to declare the objective authenticity obsolete and replace it with the existential authenticity. The argument that; the hyperreal nature of the postmodern experience and its detachment from reality makes the authenticity of the site redundant, seemed inapt for cultural heritage sites exclusively dependent on their historical and authentic values. The third reason was the inability of the postmodern paradigm to explain the new tourism phenomenon driven by the tourists search for selfdevelopment through authentic experiences. The new emerging paradigm, transmodernity seemed to offer better theoretical framework in explaining the omnivorouessness of tourists’ consumption and the authentic nature of tourist experiences. The correlational character of the research question required a descriptive correlational design and quantitative methodology. The selected research instrument for primary data collection is a self–administered questionnaire. The sampling strategy is a non–probability sampling, and the sampling method is a convenience or accidental sample. The data was collected from November 2010 to February 2011 at the Constitutional Hill National Heritage Site in Johannesburg. The final sample (436) consists of 254 foreign and 182 domestic tourists. The questionnaire was designed to identify the variables pertinent to each type of authenticity of tourists experience and of the resultant tourist experience. The data analysis provided very interesting results. Firstly, the results of crosstabulation proved that more than half (56%) of the tourists expressed strong agreement that the Constitution Hill provided them with authentic experience, hence a proof that political heritage sites are not responsible for the overall low experiential ratings of the country’s culture and heritage. Secondly, the results of the Spearman’s correlation coefficient proved that objective authenticity as an independent variable have strong positive correlation with constructed and existential authenticity hence a proof that objective authenticity cannot be declared obsolete and replaced with existential authenticity. Finally, the results of the t–test proved that motivation for learning and place of birth do not play an important role in how tourist evaluate and experience the authenticity of the site pointing to the omnivorous nature of tourist consumption. In line with the transmodern paradigm, motivation for learning plays a critical role in triggering the transformative, authentic experience distinctive of the existential authenticity. The results of the study also showed that 32% of tourists are in fact the purposeful, New Age, transmodern Cultural Creatives. Proposed theoretical model of authenticity of tourists experience presents a theoretical platform for future research studies. / Thesis (M.A. (Tourism))--North-West University, Potchefstroom Campus, 2012.
74

以資料科學技術進行轉職行為之分析 / Career Transition Analysis Using Data Science Techniques

諶宏軍, Chen, Hung Chun Unknown Date (has links)
轉職對於職涯發展來說,是非常重要的人生課題;而求職者目前在面臨轉職問題時,大多時候顯得手足無措,只能詢問親友的經驗或者憑著直覺找自己有興趣的工作;整個求職的過程就像是拿人生當賭注,運氣不好時即可能賠上美好的未來。 本篇研究使用國內某知名人力銀行的求職者資料,採用資料科學的方式,利用大量求職者的實際轉職資料來做資料分析與探勘,分析轉職高峰期、工作轉換頻率、跨職類轉職、跨產業轉職及轉職與景氣的關係,並使用J48、Naïve Bayesian Classifier、Logistic Regression、Random Forest、AdaBoost和Support Vector Machines這6種分類方法來預測轉職行為。 為了方便呈現實驗結果,本研究使用Google App Engine建立了一個轉職分析查詢系統,透過分析結果可以了解台灣各產業與各職類的轉職趨勢,而轉職預測功能也可以提供給求職者與人資人員做為參考。 / Career transition is important for employees. However, most of job seekers are helpless in decision of career transition. They can only make the decision based on the experience from their friends and family members, or by intuition. The decision of job seeking is like a gamble that may lose a better future when they faced with bad luck. This research tried to analyse and discover the behaviours of job transition from the job seeking data based on the data science approach. The job seeker’s data used in the study was obtained from the well-known job bank’s database. We analyse the behaviours of the job transition, including the peak months of transition, transition frequency, cross-job and cross-industry career transition. Moreover, we investigate the methods to predict the behavior of job transfer. Six kinds of classification algorithms were used to predict the behavior of career transfer, including the J48, Naïve Bayesian Classifier, Logistic Regression, Random Forest, AdaBoost and SVM. We develop the web-based Career Transition Analysis System to provide users the capability for behaviour analysis and prediction of career transition based on Google App Engine. The findings in this study are helpful for industry trends and career transition forecasts for job seeker and human resource staffs.
75

Návrh na snížení zákaznických reklamací / Suggestion for Reduction of Customer Complaints

Kropáčová, Lucie January 2016 (has links)
The master’s thesis is focused on evaluation of present process of managment of complaints in particular company in 2014. The evaluation is made by quality managment tools and with using correlation analysis. On the basis of acquired pieces of information there will be suggest corrective measures. These correctives measures will lead to improvement of managment process of complaints and reduce customer complaints.
76

Variação da pressão em Tahiti e sua relação com a precipitação no Brasil com ênfase no leste do nordeste / Variation of pressure in Tahiti and its relation with rainfall in Brazil with emphasis on the east northeast

Santos, André Gonçalo dos 29 April 2011 (has links)
The objective of this work was to analyze the relationship of the sea level pressure (SLP) of Tahiti and some meteorological variables over Brazil, with emphasis in the eastern coast of Northeastern Brazil (ENE). For this purpose, NCEP/NCAR reanalysis data sets of SLP, rainfall rate, outgoing longwave (OLR), zonal and meridional wind components at 850 mb level, for a period that includes two phases of Pacific Decadal Oscillation (PDO), a cold phase (1948-1976) and a warm phase (1977-1998), were used. Firstly, the variables anomaly fields were elaborated. Then, a Tahiti SLP standardized index time series (IPT) was constructed and used for correlating with the above mentioned variables anomalies over Brazil. The software GrADS was employed to constructing the variables anomaly fields and the IPT linear correlation coefficient maps. The IPT spatial correlation was performed for each variable anomalies of the cold and the warm PDO phases separately. IPT and rainfall rate correlation coefficients values, ranging from 0,3 to 0,5 , with statistically significance level up to 99%, were found over the northeastern Amazon (Trombetas river watershed) and ENE. In general, the correlation coefficients presented higher values in the PDO warm phase and the IPT performed better than other climatic indices, such as SOI, MEI and Niño 3.4, with respect to rainfall rate over Brazil. Lag correlations were performed, with the meteorological variables lagging up to 5 months the IPT. The results suggested that the IPT is a good predictor of the rainfall rate 5 months in advance, particularly in northeastern Amazon. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo deste trabalho foi analisar a relação da pressão atmosférica ao nível do mar (PNM) de Tahiti com algumas variáveis meteorológicas sobre o Brasil, com ênfase na costa leste de Nordeste Brasileiro (ENE). Para esse propósito, foram utilizados conjuntos de dados de reanálises do NCEP/NCAR das variáveis PNM, taxa de precipitação, radiação de onda longa emergente (ROLE) e componentes zonal e meridional do vento ao nível de 850 mb para um período que compreende duas fases da Oscilação Decadal do Pacífico (ODP), suas fases fria (1948-1976) e quente (1977-1998). Primeiramente, foram elaborados os campos de anomalias dessas variáveis. Em seguida, foi construída uma série temporal do índice de PNM de Tahiti padronizado (IPT), que foi correlacionado com as variáveis acima mencionadas sobre o Brasil. O software GrADS foi usado para construir os mapas de coeficientes de correlação entre o IPT e as anomalias das variáveis. A correlação espacial foi feita para cada variável nas fases fria e quente da ODP separadamente. Foram encontrados valores dos coeficientes de correlação entre o IPT e a taxa de precipitação variando de 0,3 a 0,5, com nível de significância de até 99%, para o nordeste da Amazônia (bacia do rio Trombetas) e o ENE. De maneira geral, os coeficientes de correlação apresentaram valores maiores durante a fase quente da ODP e o IPT teve um desempenho melhor que os outros índices climáticos, como o IOS, IME e Niño 3.4 com relação à taxa de precipitação sobre o Brasil. Correlações atrasadas ( lag ) foram feitas, com as variáveis meteorológicas atrasadas de até 5 meses com relação ao IPT. Os resultados sugeriram que o IPT é um bom previsor da taxa de precipitação com até 5 meses de antecedência, particularmente sobre o nordeste da Amazônia.
77

Zhodnocení cenového vývoje hovězího masa ve vybraných státech EU / Evaluation of the Beef Price Developments in Selected EU Countries

PANGRÁCOVÁ, Kristýna January 2014 (has links)
The main objective of this work is to evaluate the dependency of the price of beef in the income of households. For the six selected EU will be examined twelve consecutive period from 2001 to 2012 will be used for the calculation of trend analysis, the coefficient of elasticity and correlation index. On the basis of these results was to confirm that the four selected countries dependence prices of beef in the income of households. These states are the Czech Republic, Slovakia, Germany and Austria. In Poland and Hungary dependence was refuted.
78

Mesure du coefficient de corrélation angulaire a entre l'électron et l'antineutrino dans la désintégration ß du neutron avec le spectromètre aSPECT / Measurement of the angular correlation coefficient a between electron and antineutrino in neutron beta-decay with the spectrometer aSPECT

Maisonobe, Romain 25 February 2014 (has links)
La désintégration beta du neutron est définie par divers coefficients de corrélation mesurables qui sont utilisés pour déterminer des paramètres du Modèle Standard et rechercher de nouvelle physique. L'objectif du spectromètre aSPECT est de mesurer le coefficient a de corrélation angulaire entre l'électron et l'antineutrino avec une précision sans précédent de 1%. Ce coefficient est extrait à partir d'une mesure de haute précision du spectre d'énergie des protons. Un point central de cette thèse est l'analyse du bruit de fond, motivée par les observations de décharges durant le temps de faisceau de 2011, et par une précédente indication d'une dépendance sur le potentiel de sélection des protons. Au cours de cette thèse, plusieurs mesures ont été réalisées hors ligne, en absence de particules ionisantes issues de la désintégration du neutron. Un bruit de fond "interne" (rayons-X et ions) a été identifié. Son influence sur da/a est de l'ordre de 10^-5 à 10^-4 suivant le niveau du vide (~10^-9 mbar) et la configuration du spectromètre. L'analyse des données du temps de faisceau en 2013 permet de construire un modèle de correction des différents bruits de fond présents dans l'expérience de désintégration du neutron, en considérant sa dépendance dans le temps. La correction est d'environ 3% sur le coefficient pour une configuration et un vide standard, mais elle peut atteindre 7% dans une configuration défavorable. Pour réduire ce bruit de fond, un champ électrique de dérive est appliqué au-dessus du maximum du potentiel de sélection. Des mesures supplémentaires réalisées durant ce temps de faisceau incluaient des tests systématiques comme les effets de bord (profil du faisceau) et différentes configurations des électrodes. Afin d'obtenir le résultat final, l'analyse doit être complétée en incluant les différentes corrections et en la comparant avec des simulations des effets systématiques. / Neutron beta-decay is parametrized by several measurable correlation coefficients which are used to determine parameters of the Standard Model and to search for new physics. The aim of the retardation spectrometer aSPECT is to measure the electron-antineutrino angular correlation coefficient a with an unprecedented accuracy of well below 1%. The coefficient is extracted from a high precision measurement of the proton energy spectrum. A central point of this PhD thesis is the analysis of the background, motivated by the observations of discharges during the beam time of 2011, and an earlier indication for a dependence on the retardation potential. During this thesis, several measurements were conducted off-line, without ionizing particles from neutron decay. An "internal" background (X-rays and ions) was identified. It has an influence of 10^-5 to 10^-4 on da/a depending on the vacuum level (~10^-9 mbar) and the spectrometer settings. Within the analysis of the data from the beam time in 2013, a model was built to correct for backgrounds present in neutron decay experiment, taking into account its time dependence. The correction is about 3% on the coefficient for standard settings and vacuum but it can reach 7% for unfavorable settings. To reduce the background, a drift electric field was applied close to the maximum of the retardation potential. Additional measurements performed during this beam time included tests of systematics, in particular the edge effect (beam profile) and different electrode settings. In order to obtain the final result, the analysis has to be extended by including the different corrections and by comparing with simulations of the systematic effects.
79

Medidas de assimetria bivariada e dependência local. / Measures of bivariate asymmetry and local dependence.

Flavio Henn Ferreira 03 October 2008 (has links)
Esta tese trata de dois assuntos importantes na teoria de risco: o fenômeno da dependência local e a identificação e mensuração de assimetrias apresentadas pelos dados. A primeira parte trata de dependência local, sendo abordadas algumas medidas já analisadas na literatura. Versões locais dos coeficientes de Kendall e Spearman , baseadas na distribuição condicional dos dados, são propostas. São apresentadas algumas propriedades dessas medidas e a aplicação das mesmas a algumas cópulas. Na segunda parte são apresentados resultados sobre cópulas bivariadas que são as menos associativas e menos bi-simétricas segundo o critério de máxima distância modular. A última parte trata da não-permutabilidade e assimetria radial dos dados. Uma medida de não-permutabilidade baseada nos coeficientes de correlação condicional é proposta e aplicada a algumas distribuições. No final, o conceito de quantil bivariado é aplicado nas definições de medidas para avaliar o grau de permutabilidade e de simetria radial presentes na estrutura de dependência dos dados e de testes de hipóteses para verificar se a cópula subjacente aos dados é permutável ou radialmente simétrica. / In this thesis two important fields in risk theory are studied: the local dependence phenomenon and the identification and measuring of asymmetries contained in data. The first part deals with local dependence: some measures already studied in the literature are presented and discussed, and local versions of the coefficients Kendall and Spearman , based on the conditional distribution of data, are proposed. Properties of these measures and some examples concerning its application are treated. In the second part are presented some results about bivariate copulas which are the least associative and the least bi-symmetric according to the maximum modular distance. The last part analyses the nonexchangeability and the radial asymmetry of data. A measure of nonexchangeability based on the conditional correlation coefficient is proposed and applied to some distribution functions. At the end, the concept of bivariate quantile is applied in the definitions of measures for evaluating the degree of exchangeability and radial symmetry present in data and of hypothesis tests proposed for verifying whether the underlying copula is exchangeable or radially symmetric.
80

Titulador automático baseado em filmes digitais para determinação de dureza e alcalinidade total em águas minerais/Titulador automático baseado em filmes digitais para determinação de dureza e alcalinidade total em águas minerais

Siqueira, Lucas Alfredo 29 February 2016 (has links)
Submitted by Maike Costa (maiksebas@gmail.com) on 2017-06-21T14:26:33Z No. of bitstreams: 1 arquivototal.pdf: 3690977 bytes, checksum: 752560aa5c7d78968c32cb55f0778788 (MD5) / Made available in DSpace on 2017-06-21T14:26:33Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3690977 bytes, checksum: 752560aa5c7d78968c32cb55f0778788 (MD5) Previous issue date: 2016-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Total hardness and Total alkalinity are important physico-chemical parameters for the evaluation of water quality and are determined by volumetric analytical methods. These methods have difficult to detect the endpoint of the titration due to the difficult of viewing the color transition inherent to each of them. To circumvent this problem, here is proposed a new automatic method for the detection of the titration end point for the determination of total hardness and total alkalinity in mineral water samples. The proposed flow-batch titrator consists of a peristaltic pump, five three-way solenoid valves, a magnetic stirrer, an electronic actuator, an Arduino MEGA 2560TM board, a mixing chamber and a webcam. The webcam records the digital movie (DM) during the addition of the titrant towards mixing chamber, also recording the color variations resulting from chemical reactions between titrant and sample within chamber. While the DM is recorded, it is decompiled into frames ordered sequentially at a constant rate of 30 frames per second (FPS). The first frame is used as a reference to define the region of interest (RI) of 48 × 50 pixels and the R channel values, which are used to calculate the Pearson's correlation coefficient (r) values. r is calculated between the R values of the initial frame and each subsequent frame. The titration curves are plotted in real time using the values of r (ordinate axis) and the total opening time of the valve titrant (abscissa axis). The end point is estimated by the second derivative method. A software written in ActionScript 3.0 language manages all analytical steps and data treatment in real time. The feasibility of the method was attested by its application for the analysis of natural water samples. Results were compared with classical titration and did not present statistically significant differences when the paired ttest at the 95% confidence level was applied. The proposed method is able to process about 71 samples per hour, and its precision was confirmed by overall relative standard deviation (RSD) values, always lower than the 2,4% for total hardness and 1,4% for total alkalinity. / A dureza total e a alcalinidade total são importantes parâmetros físico-químicos para avaliação da qualidade de águas e são determinados por métodos volumétricos de análise. Estes métodos apresentam difícil detecção do ponto final da titulação devido à dificuldade de visualização das transições de cores inerentes a cada um deles. Para contornar este problema, foi proposta neste trabalho uma nova metodologia automática para a detecção do ponto final nas determinações de dureza total e alcalinidade total em águas. O titulador em fluxo-batelada proposto é composto de uma bomba peristáltica, cinco válvulas solenoides de três vias, um agitador magnético, um acionador de válvulas, uma placa Arduíno MEGA 2560TM, uma câmara de mistura e uma webcam. O programa de gerenciamento e controle do titulador foi escrito em linguagem ActionScript 3.0. A webcam grava o filme digital durante a adição do titulante na câmara de mistura, registrando as variações de cor decorrentes das reações químicas entre titulante e amostra no interior de câmara. Enquanto o filme é gravado, este é decomposto em quadros ordenados sequencialmente a uma taxa constante de 30 quadros por segundo (FPS). O primeiro quadro é utilizado como referência para definir uma região de interesse (RI) com 48 x 50 pixels, na qual seus valores R, G e B são utilizados para calcular os valores de coeficiente de correlação de Pearson (r). O valor de r é calculado entre os valores de R do quadro inicial e de cada quadro subsequente. As curvas de titulação são obtidas em tempo real usando os valores de r (ordenadas) e o tempo total de abertura da válvula de titulante (abscissas). O ponto final é estimado pelo método de segunda derivada. O método foi aplicado na análise de águas minerais e os resultados foram comparados com a titulação clássica, não apresentando diferenças estatisticamente significativas com aplicação do teste t pareado a 95% de confiança. O método proposto foi capaz de processar até 71 amostras por hora e a sua precisão foi confirmada pelos valores de desvio padrão relativos (DPR) globais, sempre inferiores as 2,4% para dureza total e 1,4% para alcalinidade total.

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