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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.
111

A Predictive (RIVPACS-Type) Model for Streams of the Western Allegheny Plateau

North, Sheila H. 02 October 2008 (has links)
No description available.
112

Prediction of hypertensive disorders in pregnancy by combined uterine artery Doppler, serum biomarkers and maternal characteristics

An, Na 06 1900 (has links)
Objectif: Évaluer l'efficacité du dépistage de l’hypertension gestationnelle par les caractéristiques démographiques maternelles, les biomarqueurs sériques et le Doppler de l'artère utérine au premier et au deuxième trimestre de grossesse. Élaborer des modèles prédictifs de l’hypertension gestationnelle fondées sur ces paramètres. Methods: Il s'agit d'une étude prospective de cohorte incluant 598 femmes nullipares. Le Doppler utérin a été étudié par échographie transabdominale entre 11 +0 à 13 +6 semaines (1er trimestre) et entre 17 +0 à 21 +6 semaines (2e trimestre). Tous les échantillons de sérum pour la mesure de plusieurs biomarqueurs placentaires ont été recueillis au 1er trimestre. Les caractéristiques démographiques maternelles ont été enregistrées en même temps. Des courbes ROC et les valeurs prédictives ont été utilisés pour analyser la puissance prédictive des paramètres ci-dessus. Différentes combinaisons et leurs modèles de régression logistique ont été également analysés. Résultats: Parmi 598 femmes, on a observé 20 pré-éclampsies (3,3%), 7 pré-éclampsies précoces (1,2%), 52 cas d’hypertension gestationnelle (8,7%) , 10 cas d’hypertension gestationnelle avant 37 semaines (1,7%). L’index de pulsatilité des artères utérines au 2e trimestre est le meilleur prédicteur. En analyse de régression logistique multivariée, la meilleure valeur prédictive au 1er et au 2e trimestre a été obtenue pour la prévision de la pré-éclampsie précoce. Le dépistage combiné a montré des résultats nettement meilleurs comparés avec les paramètres maternels ou Doppler seuls. Conclusion: Comme seul marqueur, le Doppler utérin du deuxième trimestre a la meilleure prédictive pour l'hypertension, la naissance prématurée et la restriction de croissance. La combinaison des caractéristiques démographiques maternelles, des biomarqueurs sériques maternels et du Doppler utérin améliore l'efficacité du dépistage, en particulier pour la pré-éclampsie nécessitant un accouchement prématuré. / Objective: To evaluate the screening efficacy of maternal demographic characteristics, serum biomarkers and uterine artery Doppler (uaD) during the first and the second trimester for the hypertensive disorders of pregnancy. To elaborate prediction models of these diseases based on the combination of selected maternal demographic characteristics, maternal serum biomarkers and uaD indexes. Methods: This is a prospective pregnant cohort study of 598 singleton nulliparous consecutive women. UaD investigation was performed by transabdominal sonography between 11+0 and 13+6 weeks, and between 17+0 and 21+6 weeks. All the serum samples for measurement of several placental biomarkers were collected at the first trimester. Maternal demographic characteristics were recorded at the same time. Receiver operating characteristic curves and predictive values were used to analyze the predictive powers of the above parameters. Different combinations and their logistic regression predictive models were analyzed. Results: Among 598 women, 20 developed preeclampsia (3.3%), 7 developed early-onset preeclampsia (1.2%), 52 developed gestational hypertension (8.7%), 10 developed gestational hypertension with delivery before 37 weeks (1.7%). Second trimester uterine artery pulsatility index was the best predictor with statistical significance for all the outcomes. In the multivariable logistic regression analysis, the best predictive value in the first and second trimester was obtained for the prediction of early onset preeclampsia. The combined screening showed significantly better results compared to either maternal parameters or Doppler alone. Conclusion: As a single marker, second trimester Doppler has the highest predictive value for hypertensive disorders, preterm birth and SGA. Combination of the maternal demographic characteristics, maternal serum biomarker and uaD improves the screening efficacy, especially when this necessitates early delivery.
113

Développement du modèle E-PPR78 pour prédire les équilibres de phases et les grandeurs de mélange de systèmes complexes d’intérêt pétrolier sur de larges gammes de températures et de pressions / Development of the E-PPR78 model in order to predict the phase equilibria and the mixing properties of complex systems of petroleum interest over wide ranges of temperature and pressure

Qian, Junwei 12 December 2011 (has links)
Nous avons développé un modèle prédictif, utilisant le principe de contribution de groupes, pour prédire avec précision, le comportement des fluides pétroliers. Ce modèle baptisé PPR78 utilise l’équation d’état de Peng et Robinson et des règles de mélange de type Van der Waals avec un coefficient d’interaction binaire kij, dépendant de la température. De telles règles de mélange sont équivalentes à celles obtenues en combinant à compacité constante une fonction d’excès de type Van Laar et une équation d’état cubique.La première partie de cette étude a consisté à étendre le domaine d’application du modèle PPR78 aux systèmes contenant de l’eau, des alcènes et de l’hydrogène, en définissant six nouveaux groupes élémentaires. Une bonne précision du modèle est obtenue pour décrire les équilibres de phases de systèmes binaires impliquant ces constituants, notamment pour les systèmes présentant des diagrammes de phases de Type I et de Type II. Dans la deuxième partie l’ensemble des paramètres de groupes ont été réajustés, non seulement sur des données d’équilibres de phases mais également sur des données de grandeur de mélange. L’avantage de ce nouveau modèle E-PPR78 est qu’il permet de restituer les équilibres de phases avec une précision équivalente au modèle original et qu’il conduit à une très nette amélioration de la prédiction des enthalpies d’excès et des capacités calorifiques d’excès. / We have developed a predictive model, by means of a group contribution method, in order to predict with accuracy, the behavior of petroleum fluids. The model called PPR78 uses the Peng-Robinson equation of state and Van der Waals-type mixing rules with a temperature dependent binary interaction parameter kij. Such mixing rules are identical to those obtained by combining at constant packing fraction, a Van Laar-type excess function and a cubic equation of state.The first part of this study consisted in extending the application of the model PPR78 to systems containing water, alkenes and hydrogen, by defining six new elementary groups. The phase equilibria of binary systems involving these components are accurately described by the model, especially for the phase diagrams of Type I and Type II. In the second part, all the group parameters of the original model were re-fitted by using the phase equilibrium data, as well as the mixing property data. The advantage of this new model E-PPR78 is that it is capable to correlate the phase equilibria with an accuracy which is equivalent to the original model and it produces a very clear improvement in the prediction of excess enthalpies and excess heat capacities.
114

Développement du modèle PPR78 pour décrire, comprendre et prédire les diagrammes de phases hautes et basses pressions des systèmes binaires et des fluides pétroliers / Development of the PPR78 model in order to describe, understand and predict high and low pressure phase diagrams of binary systems and petroleum mixtures

Privat, Romain 27 November 2008 (has links)
Le développement d'un modèle thermodynamique prédictif PPR78, basé sur le concept de contributions de groupes, a été entrepris afin de pouvoir prédire avec précision, le comportement des fluides pétroliers. PPR78 utilise l’équation d’état de Peng et Robinson et les règles de mélange de Van der Waals avec un seul coefficient d’interactions binaires kij, dépendant de la température. Cette approche est rigoureusement équivalente à l’utilisation de règles de mélange à compacité constante avec un modèle d’énergie de Gibbs molaire d’excès, gE, de type Van Laar. Pour développer ce modèle, une étude approfondie des équilibres entre phases fluides des systèmes binaires a été réalisée en deux temps. Dans un premier, une étude phénoménologique permet d'éclairer sous un jour nouveau la classification proposée par Van Konynenburg et Scott qui décrit qualitativement les comportements de ces systèmes. Dans un second temps, quelques principes généraux de calcul des diagrammes d’équilibre de phases isothermes, isobares et globaux sont exposés. L’étude de la stabilité thermodynamique globale occupe une place essentielle au sein de ces calculs. Une fois ces étapes préliminaires franchies, l’extension du modèle aux groupes CO2, N2, H2S et sulfhydryle est réalisée. Une bonne précision du modèle est obtenue pour décrire les systèmes binaires impliquant ces quatre groupes. Enfin, le comportement des fluides pétroliers est souvent prédit avec une précision de l'ordre de l'erreur expérimentale par PPR78 / A predictive thermodynamic model, based on the group contribution concept, and called PPR78, has been developed in order to be able to predict, with high accuracy, the behaviour of petroleum fluids. PPR78 uses the Peng-Robinson equation of state with Van der Waals mixing rules and a temperature dependent binary interaction parameter kij. This method is the equivalent to the constant packing fraction mixing rules with a Van Laar excess Gibbs energy model (gE). To develop the model, an in-depth study on binary systems fluid phase equilibria, was carried out. It was divided into two parts. Firstly, a phenomenological study made a reappraisal of the Van Konynenburg and Scott classification possible. Secondly, some general rules for the calculation of isothermal, isobaric and global phase equilibrium diagrams were demonstrated. It is important to note that the study of the global thermodynamic stability is essential in the calculations. Once these preliminary steps were realized, the extension of the model to the CO2, N2, H2S and sulfhydryl groups was performed. The fluid phase behaviour of binary systems involving these four groups was accurately calculated by the PPR78 model. Finally, the properties of petroleum fluids were predicted by PPR78 with an accuracy close to the experimental uncertainty
115

Modelo de análisis predictivo para determinar clientes con tendencia a la deserción en bancos peruanos

Barrueta Meza, Renzo André, Castillo Villarreal, Edgar Jean Paul 06 December 2018 (has links)
En la actualidad, el rol que cumplen los bancos en la economía del país y el impacto que tienen en las diferentes clases sociales es cada vez más importante. Estos siempre han sido un mercado que históricamente ha recibido un gran número de quejas y reclamaciones. Es por ello que, un mal servicio por parte del proveedor, una deficiente calidad de los productos y un precio fuera de mercado son las principales razones por las que los clientes abandonan una entidad bancaria. Esta situación va aumentando cada vez más y los bancos muestran su preocupación por este problema intentando implementar modelos que hasta el momento no han logrado cumplir con los objetivos. Además, existe un elevado nivel de competencia que obliga a las entidades financieras a velar por la lealtad de sus clientes para intentar mantenerlos e incrementar su rentabilidad. Este proyecto propone un Modelo de Análisis Predictivo soportado con la herramienta SAP Predictive Analytics, con el fin de ayudar en la toma de decisiones para la retención o fidelización de los clientes potenciales con tendencia a la deserción en la entidad bancaria. Esta propuesta se realizó mediante la necesidad de los mismos de conocer la exactitud de deserción de sus clientes categorizados potenciales. Se desarrolló una interfaz web como canal entre el Modelo de Análisis Predictivo propuesto y la entidad bancaria, con el fin de mostrar el resultado obtenido por el modelo indicando la exactitud, en porcentaje, de los clientes con tendencia a desertar. Además, como Plan de continuidad se propone 2 proyectos en base a la escalabilidad del Modelo de análisis predictivo propuesto, apoyándonos en la información obtenida en la etapa de análisis del modelo mismo. / Currently, the role played by banks in the country's economy and the impact they have on different social classes is increasingly important. These have always been a market that has historically received a large number of complaints and claims. It is therefore, poor service by the supplier, poor product quality and a price outside the market are the main reasons why customers leave a bank. This situation is increasingly and banks. In addition, there is a high level of competition that forces financial institutions and the loyalty of their customers to try to maintain them and increase their profitability. This project proposes a Predictive Analysis Model supported with the SAP Predictive Analytics tool, in order to help in making decisions for the retention or loyalty of clients with the tendency to drop out in the bank. This proposal was made through the need to know the accuracy of the desertion of its categorized clients. A web interface is shown as a channel between the Predictive Analysis Model and the bank, in order to show the result by the model that indicates the accuracy, in percentage, of clients with a tendency to defect. In addition, as a continuity plan, 2 projects are proposed based on the scalability of the Predictive Analysis Model, based on the information in the analysis stage of the model itself. / Tesis
116

Manufacture, modelling and characterisation of novel composite tubes

Agwubilo, Ikenna January 2016 (has links)
This thesis primarily focused on the development of novel composite tubes by braiding. The objective was to use hierarchical scale technique, i.e., micro, meso and macro scales, with the transfer of information from one scale to another to develop novel braided composite tubes. This research was conducted and reported in three journal papers. The aim of the first paper was to predict plane elastic properties for E-glass/epoxy braided composite structures at different braid orientations, by analytical and finite element techniques. The lenticular shape has been used to describe the geometry of the tow. Modified lenticular geometric model was developed to improve an existing geometric model, in terms of tow parameters, thereafter, plane elastic properties from Chamis micromechanical model for E-glass fibre and epoxy matrix without any knockdown effects were used as benchmark to develop predictive models, namely; Lekhnitskii's methodology and braided unit cell meso-scale finite element model to account for the effects of tow geometry, undulations/crimp, cross-over and braid orientations on the plane elastic properties of E-glass/epoxy composite. The results showed agreement in trend between the predictive models, Chamis micromechanical model, and a similar existing model. However, the plane elastic properties were knocked down in predictive models by 30% in the E11 direction and 32% in the E22 direction, when compared with Chamis micro-mechanical model for largest ±65° braid angle, among the braid angles, considered. The aim of the second paper was to manufacture E-glass/epoxy braided tubes at different braid orientations by vacuum bag infusion technique, conduct internal pressure tests, and determine the hoop and axial moduli of the infused tubes. Lekhnitskii's methodology was also used to develop plane elastic moduli by experiment using microscopy results, and by calculation. The experimental elastic moduli of the infused tubes and the experimental elastic moduli from Lekhnitskii's methodology were used to compare the predictive elastic moduli for E-glass/epoxy braided structures by Chamis micro-mechanical model, and the braided unit cell meso-scale finite element model. The two were from another paper. Results showed a perfect agreement in trend between the experimental results and the predictive results. However, the values of the experimental results were close but lower than the predicted results. Optical microscopy was performed on braided tube cross-section to evaluate the level of crimp or undulation. This was done by the determination of tow centreline crimp angle and aspect ratio. Results show that when compared with the predicted crimp, there was an agreement in trend, although the experimental results were lower than the predicted. Also, the knockdown factor was evaluated and used to quantify the reduction in experimental elastic moduli when compared with the predicted. Results showed that the absences of crimp in the Chamis model caused a tremendous difference between it, other predicted models and the experiment results. The elastic moduli of Chamis were by far higher than all others, including other predictive models. The purpose of the third paper was to manufacture E-glass/epoxy braided tube at ±31°, ±45°, ±55°, ±65° braid orientations using vacuum bagging and resin infusion technique, to design and manufacture a rig for tube internal pressures experiment, to determine the hoop and axial stress performances of the tubes by internal pressure experiment, to compare experimental results with laminate analysis predictions to evaluate the effect of crimp on the internal pressure performance of the braided tubes. To use E-glass braided tow meso-scale unit cell finite element model to predict the tow critical stresses, and the optimum braided tube architecture, using tube hoop and axial failure stresses or strains. The tubes were manufactured and subjected to internal pressure test (2:1), to failure. Failure mode was by weeping and bursting. Hoop stress was twice the axial stress. The highest value of hoop stress was at the ±65° braid angle, higher than the hoop stresses at the ±31°, ±45°, and ±55 ° braid angles by 50%, 39%, and 28% respectively. Hoop stress increased with increase in braid angle. The experimental results were validated by laminate analysis predictions by Chamis micro-mechanical model and Lekhnitskii's methodology, and the trend of the laminate analysis prediction matched that of the experimental results. However, the predicted values were higher than the experimental results by 21%, 14%, 11%, 10% for the ±31°, ±45°, ±55°, ±65° braid angles for the Chamis micro-mechanical model and 5%, 7%, 7%, 5% for the ±31°, ±45°, ±55°, ±65 braid angles respectively for the Lekhnitskii's model, showing the severe effect of crimp in the experimental tube, mostly when compared with Chamis micro-mechanical model. Braided tow unit cell finite element model prediction, showed that tow axial stresses increased with increase in braid angle, while the tow transverse stresses decreased with increase in braid angle. The predictions showed that the tow critical stresses and the tube optimum braided architecture lie between the ±65° and 90° braid angles. The tow critical stresses are the stresses at which the tow decreasing transverse stress and the tow increasing axial stress causes the tube to fail.
117

信用卡信用風險預警範例學習系統之研究 / Predicting Credit Card Risks Using Learning From Examples

馬芳資, Ma, Fang-tsz Unknown Date (has links)
近年來,信用卡市場快速地成長,發卡銀行亦大量地發卡,然而目前國內 發卡銀行在整個信用卡信用風險管理上,大都採行人類專家經驗判斷的方 式進行。發卡銀行隨著持卡人數快速地增加,其信用資料亦呈等比例急速 上升,若仍採用人工處理方式,除了會大幅增加工作負荷外,其授信品質 也不易控制。因此,本研究擬引進資訊技術來解決大量信用卡信用資料之 信用管理問題。 首先,我們探討信用卡信用管理業務,並根據其作業 流程來建構一信用卡信用管理自動化的架構,此架構包括徵信驗證系統、 審核系統、預警系統、高風險客戶管理系統、及催收系統等五個系統,其 目的在於輔助授信管理之業務、減少授管人員的工作負荷、以有效控制授 信品質、及降低授信的風險。 其次,本研究針對上述信用卡信用管理 自動化中的預警系統,利用範例學習法來建立信用卡信用風險預警範例學 習系統,且實際以一家發卡銀行的信用資料來建立並驗證四個預警模式, 期能事先讓系統自動查核信用不良之客戶。此四類預警模式為: (一)提前 預警模式(二)群體決策預警模式(三)追蹤管理預警模式(四)例外管理預警 模式 最後,我們亦提出一些未來研究之課題,期能進一步發展本研究 之信用卡信用管理自動化系統及預警模式,以推廣應用至各發卡機構。
118

Analytical measurements and predictions of perchlorate ion concentration in sodium hypochlorite solutions and drinking water kinetics of perchlorate ion formation and effects of associated contaminants /

Pisarenko, Aleksey N. January 2009 (has links)
Title from second page of PDF document. Includes bibliographical references (p. 144-152).
119

Cactus Hill, Rubis-Pearsall and Blueberry Hill : one is an accident; two is a coincidence; three is a pattern : predicting "old dirt" in the Nottoway river valley of Southeastern Virginia, USA

Johnson, Michael Farley January 2012 (has links)
This thesis covers more than thirty years of the author's research into the Paleoamerican period of the Middle Atlantic Region of North America, including the last 19+ years of focused work on the Cactus Hill site (44SX202) and replication of the Paleoamerican occupation discovered there. Using a landform and geology based predictive model derived from the Paleoamerican occupation at Cactus Hill, the author directed preliminary archaeological testing in three other areas of the same Nottoway River Valley, where Cactus Hill is located. These areas were the Barr site, located 11 miles (18 km.) downriver from Cactus Hill; the Chub Sandhill Natural Resource Conservation Area, located 19 miles (30 km.) downriver from Cactus Hill; and the Blueberry Hill site (44SX327), located approximately 1,000 feet (300 meters) east of Cactus Hill. The latter two produced OSL dated, pre-Younger-Dryas landforms, as predicted. The Rubis-Pearsall site (44SX360), located in the Chub Sandhill preserve also produced a buried Paleoamerican, Clovis age cultural level confirming the model. In addition to the OSL dates, Blueberry Hill also produced a distinct and apparently discrete activity surface with a possible pre-Clovis age Cactus Hill point at the same depth as the Paleoamerican levels at Cactus Hill and Rubis-Pearsall.
120

Prediction of hypertensive disorders in pregnancy by combined uterine artery Doppler, serum biomarkers and maternal characteristics

An, Na 06 1900 (has links)
RÉSUMÉ Objectif: Évaluer l'efficacité du dépistage de l’hypertension gestationnelle par les caractéristiques démographiques maternelles, les biomarqueurs sériques et le Doppler de l'artère utérine au premier et au deuxième trimestre de grossesse. Élaborer des modèles prédictifs de l’hypertension gestationnelle fondées sur ces paramètres. Methods: Il s'agit d'une étude prospective de cohorte incluant 598 femmes nullipares. Le Doppler utérin a été étudié par échographie transabdominale entre 11 +0 à 13 +6 semaines (1er trimestre) et entre 17 +0 à 21 +6 semaines (2e trimestre). Tous les échantillons de sérum pour la mesure de plusieurs biomarqueurs placentaires ont été recueillis au 1er trimestre. Les caractéristiques démographiques maternelles ont été enregistrées en même temps. Des courbes ROC et les valeurs prédictives ont été utilisés pour analyser la puissance prédictive des paramètres ci-dessus. Différentes combinaisons et leurs modèles de régression logistique ont été également analysés. Résultats: Parmi 598 femmes, on a observé 20 pré-éclampsies (3,3%), 7 pré-éclampsies précoces (1,2%), 52 cas d’hypertension gestationnelle (8,7%) , 10 cas d’hypertension gestationnelle avant 37 semaines (1,7%). L’index de pulsatilité des artères utérines au 2e trimestre est le meilleur prédicteur. En analyse de régression logistique multivariée, la meilleure valeur prédictive au 1er et au 2e trimestre a été obtenue pour la prévision de la pré-éclampsie précoce. Le dépistage combiné a montré des résultats nettement meilleurs comparés avec les paramètres maternels ou Doppler seuls. Conclusion: Comme seul marqueur, le Doppler utérin du deuxième trimestre a la meilleure prédictive pour l'hypertension, la naissance prématurée et la restriction de croissance. La combinaison des caractéristiques démographiques maternelles, des biomarqueurs sériques maternels et du Doppler utérin améliore l'efficacité du dépistage, en particulier pour la pré-éclampsie nécessitant un accouchement prématuré. Mot clés: Hypertension gestationnelle, Doppler utérins, Biomarqueurs sériques maternels, Caractéristiques démographiques maternelles, Dépistage, Modèle prédictif Multivarié. / ABSTRACT Objective: To evaluate the screening efficacy of maternal demographic characteristics, serum biomarkers and uterine artery Doppler (uaD) during the first and the second trimester for the hypertensive disorders of pregnancy. To elaborate prediction models of these diseases based on the combination of selected maternal demographic characteristics, maternal serum biomarkers and uaD indexes. Methods: This is a prospective pregnant cohort study of 598 singleton nulliparous consecutive women. UaD investigation was performed by transabdominal sonography between 11+0 and 13+6 weeks, and between 17+0 and 21+6 weeks. All the serum samples for measurement of several placental biomarkers were collected at the first trimester. Maternal demographic characteristics were recorded at the same time. Receiver operating characteristic curves and predictive values were used to analyze the predictive powers of the above parameters. Different combinations and their logistic regression predictive models were analyzed. Results: Among 598 women, 20 developed preeclampsia (3.3%), 7 developed early-onset preeclampsia (1.2%), 52 developed gestational hypertension (8.7%), 10 developed gestational hypertension with delivery before 37 weeks (1.7%). Second trimester uterine artery pulsatility index was the best predictor with statistical significance for all the outcomes. In the multivariable logistic regression analysis, the best predictive value in the first and second trimester was obtained for the prediction of early onset preeclampsia. The combined screening showed significantly better results compared to either maternal parameters or Doppler alone. Conclusion: As a single marker, second trimester Doppler has the highest predictive value for hypertensive disorders, preterm birth and SGA. Combination of the maternal demographic characteristics, maternal serum biomarker and uaD improves the screening efficacy, especially when this necessitates early delivery. Key words: Hypertensive disorders of pregnancy, Doppler, Maternal serum biomarkers, Maternal demographic characteristics, Screening, Multivariable predictive model.

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