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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

Simulating human-prosthesis interaction and informing robotic prosthesis design using metabolic optimization

Handford, Matthew Lawrence January 2018 (has links)
No description available.
72

Assessing the Influence of Different Inland Lake Management Strategies on Human-Mediated Invasive Species Spread

Morandi, Marc Joseph 22 August 2013 (has links)
No description available.
73

AI-Based Transport Mode Recognition for Transportation Planning Utilizing Smartphone Sensor Data From Crowdsensing Campaigns

Grubitzsch, Philipp, Werner, Elias, Matusek, Daniel, Stojanov, Viktor, Hähnel, Markus 11 May 2023 (has links)
Utilizing smartphone sensor data from crowdsen-sing (CS) campaigns for transportation planning (TP) requires highly reliable transport mode recognition. To address this, we present our RNN-based AI model MovDeep, which works on GPS, accelerometer, magnetometer and gyroscope data. It was trained on 92 hours of labeled data. MovDeep predicts six transportation modes (TM) on one second time windows. A novel postprocessing further improves the prediction results. We present a validation methodology (VM), which simulates unknown context, to get a more realistic estimation of the real-world performance (RWP). We explain why existing work shows overestimated prediction qualities, when they would be used on CS data and why their results are not comparable with each other. With the introduced VM, MovDeep still achieves 99.3 % F1 -Score on six TM. We confirm the very good RWP for our model on unknown context with the Sussex-Huawei Locomotion data set. For future model comparison, both publicly available data sets can be used with our VM. In the end, we compare MovDeep to a deterministic approach as a baseline for an average performing model (82 - 88 % RWP Recall) on a CS data set of 540 k tracks, to show the significant negative impact of even small prediction errors on TP.
74

[pt] ENSAIOS EM PREDIÇÃO DO TEMPO DE PERMANÊNCIA EM UNIDADES DE TERAPIA INTENSIVA / [en] ESSAYS ON LENGTH OF STAY PREDICTION IN INTENSIVE CARE UNITS

IGOR TONA PERES 28 June 2021 (has links)
[pt] O tempo de permanência (LoS) é uma das métricas mais utilizadas para avaliar o uso de recursos em Unidades de Terapia Intensiva (UTI). Esta tese propõe uma metodologia estruturada baseada em dados para abordar três principais demandas de gestores de UTI. Primeiramente, será proposto um modelo de predição individual do LoS em UTI, que pode ser utilizado para o planejamento dos recursos necessários. Em segundo lugar, tem-se como objetivo desenvolver um modelo para predizer o risco de permanência prolongada, o que auxilia na identificação deste tipo de paciente e assim uma ação mais rápida de intervenção no mesmo. Finalmente, será proposto uma medida de eficiência ajustada por case-mix capaz de realizar análises comparativas de benchmark entre UTIs. Os objetivos específicos são: (i) realizar uma revisão da literatura dos fatores que predizem o LoS em UTI; (ii) propor uma metodologia data-driven para predizer o LoS individual do paciente na UTI e o seu risco de longa permanência; e (iii) aplicar essa metodologia no contexto de um grande conjunto de UTIs de diferentes tipos de hospitais. Os resultados da revisão da literatura apresentaram os principais fatores de risco que devem ser considerados em modelos de predição. Em relação ao modelo preditivo, a metodologia proposta foi aplicada e validada em um conjunto de dados de 109 UTIs de 38 diferentes hospitais brasileiros. Este conjunto continha um total de 99.492 internações de 01 de janeiro a 31 de dezembro de 2019. Os modelos preditivos construídos usando a metodologia proposta apresentaram resultados precisos comparados com a literatura. Estes modelos propostos têm o potencial de melhorar o planejamento de recursos e identificar precocemente pacientes com permanência prolongada para direcionar ações de melhoria. Além disso, foi utilizado o modelo de predição proposto para construir uma medida não tendenciosa para benchmarking de UTIs, que também foi validada no conjunto de dados estudado. Portanto, esta tese propôs um guia estruturado baseado em dados para gerar predições para o tempo de permanência em UTI ajustadas ao contexto em que se deseja avaliar. / [en] The length of stay (LoS) in Intensive Care Units (ICU) is one of the most used metrics for resource use. This thesis proposes a structured datadriven methodology to approach three main demands of ICU managers. First, we propose a model to predict the individual ICU length of stay, which can be used to plan the number of beds and staff required. Second, we develop a model to predict the risk of prolonged stay, which helps identifying prolonged stay patients to drive quality improvement actions. Finally, we build a case-mix-adjusted efficiency measure (SLOSR) capable of performing non-biased benchmarking analyses between ICUs. To achieve these objectives, we divided the thesis into the following specific goals: (i) to perform a literature review and meta-analysis of factors that predict patient s LoS in ICUs; (ii) to propose a data-driven methodology to predict the numeric ICU LoS and the risk of prolonged stay; and (iii) to apply this methodology in the context of a big set of ICUs from mixed-type hospitals. The literature review results presented the main risk factors that should be considered in future prediction models. Regarding the predictive model, we applied and validated our proposed methodology to a dataset of 109 ICUs from 38 different Brazilian hospitals. The included dataset contained a total of 99,492 independent admissions from January 01 to December 31, 2019. The predictive models to numeric ICU LoS and to the risk of prolonged stay built using our data-driven methodology presented accurate results compared to the literature. The proposed models have the potential to improve the planning of resources and early identifying prolonged stay patients to drive quality improvement actions. Moreover, we used our prediction model to build a non-biased measure for ICU benchmarking, which was also validated in our dataset. Therefore, this thesis proposed a structured data-driven guide to generating predictions to ICU LoS adjusted to the specific environment analyzed.
75

Maskininlärning som verktyg för att extrahera information om attribut kring bostadsannonser i syfte att maximera försäljningspris / Using machine learning to extract information from real estate listings in order to maximize selling price

Ekeberg, Lukas, Fahnehjelm, Alexander January 2018 (has links)
The Swedish real estate market has been digitalized over the past decade with the current practice being to post your real estate advertisement online. A question that has arisen is how a seller can optimize their public listing to maximize the selling premium. This paper analyzes the use of three machine learning methods to solve this problem: Linear Regression, Decision Tree Regressor and Random Forest Regressor. The aim is to retrieve information regarding how certain attributes contribute to the premium value. The dataset used contains apartments sold within the years of 2014-2018 in the Östermalm / Djurgården district in Stockholm, Sweden. The resulting models returned an R2-value of approx. 0.26 and Mean Absolute Error of approx. 0.06. While the models were not accurate regarding prediction of premium, information was still able to be extracted from the models. In conclusion, a high amount of views and a publication made in April provide the best conditions for an advertisement to reach a high selling premium. The seller should try to keep the amount of days since publication lower than 15.5 days and avoid publishing on a Tuesday. / Den svenska bostadsmarknaden har blivit alltmer digitaliserad under det senaste årtiondet med nuvarande praxis att säljaren publicerar sin bostadsannons online. En fråga som uppstår är hur en säljare kan optimera sin annons för att maximera budpremie. Denna studie analyserar tre maskininlärningsmetoder för att lösa detta problem: Linear Regression, Decision Tree Regressor och Random Forest Regressor. Syftet är att utvinna information om de signifikanta attribut som påverkar budpremien. Det dataset som använts innehåller lägenheter som såldes under åren 2014-2018 i Stockholmsområdet Östermalm / Djurgården. Modellerna som togs fram uppnådde ett R²-värde på approximativt 0.26 och Mean Absolute Error på approximativt 0.06. Signifikant information kunde extraheras from modellerna trots att de inte var exakta i att förutspå budpremien. Sammanfattningsvis skapar ett stort antal visningar och en publicering i april de bästa förutsättningarna för att uppnå en hög budpremie. Säljaren ska försöka hålla antal dagar sedan publicering under 15.5 dagar och undvika att publicera på tisdagar.
76

Machine Learning and Multivariate Statistical Tools for Football Analytics

Malagón Selma, María del Pilar 05 October 2023 (has links)
[ES] Esta tesis doctoral se centra en el estudio, implementación y aplicación de técnicas de aprendizaje automático y estadística multivariante en el emergente campo de la analítica deportiva, concretamente en el fútbol. Se aplican procedimientos comunmente utilizados y métodos nuevos para resolver cuestiones de investigación en diferentes áreas del análisis del fútbol, tanto en el ámbito del rendimiento deportivo como en el económico. Las metodologías empleadas en esta tesis enriquecen las técnicas utilizadas hasta el momento para obtener una visión global del comportamiento de los equipos de fútbol y pretenden ayudar al proceso de toma de decisiones. Además, la metodología se ha implementado utilizando el software estadístico libre R y datos abiertos, lo que permite la replicabilidad de los resultados. Esta tesis doctoral pretende contribuir a la comprensión de los modelos de aprendizaje automático y estadística multivariante para la predicción analítica deportiva, comparando su capacidad predictiva y estudiando las variables que más influyen en los resultados predictivos de estos modelos. Así, siendo el fútbol un juego de azar donde la suerte juega un papel importante, se proponen metodologías que ayuden a estudiar, comprender y modelizar la parte objetiva de este deporte. Esta tesis se estructura en cinco bloques, diferenciando cada uno en función de la base de datos utilizada para alcanzar los objetivos propuestos. El primer bloque describe las áreas de estudio más comunes en la analítica del fútbol y las clasifica en función de los datos utilizados. Esta parte contiene un estudio exhaustivo del estado del arte de la analítica del fútbol. Así, se recopila parte de la literatura existente en función de los objetivos alcanzados, conjuntamente con una revisión de los métodos estadísticos aplicados. Estos modelos son los pilares sobre los que se sustentan los nuevos procedimientos aquí propuestos. El segundo bloque consta de dos capítulos que estudian el comportamiento de los equipos que alcanzan la Liga de Campeones o la Europa League, descienden a segunda división o permanecen en mitad de la tabla. Se proponen varias técnicas de aprendizaje automático y estadística multivariante para predecir la posición de los equipos a final de temporada. Una vez realizada la predicción, se selecciona el modelo con mejor precisión predictiva para estudiar las acciones de juego que más discriminan entre posiciones. Además, se analizan las ventajas de las técnicas propuestas frente a los métodos clásicos utilizados hasta el momento. El tercer bloque consta de un único capítulo en el que se desarrolla un código de web scraping para facilitar la recuperación de una nueva base de datos con información cuantitativa de las acciones de juego realizadas a lo largo del tiempo en los partidos de fútbol. Este bloque se centra en la predicción de los resultados de los partidos (victoria, empate o derrota) y propone la combinación de una técnica de aprendizaje automático, random forest, y la regresión Skellam, un método clásico utilizado habitualmente para predecir la diferencia de goles en el fútbol. Por último, se compara la precisión predictiva de los métodos clásicos utilizados hasta ahora con los métodos multivariantes propuestos. El cuarto bloque también comprende un único capítulo y pertenece al área económica del fútbol. En este capítulo se aplica un novedoso procedimiento para desarrollar indicadores que ayuden a predecir los precios de traspaso. En concreto, se muestra la importancia de la popularidad a la hora de calcular el valor de mercado de los jugadores, por lo que este capítulo propone una nueva metodología para la recogida de información sobre la popularidad de los jugadores. En el quinto bloque se revelan los aspectos más relevantes de esta tesis para la investigación y la analítica en el fútbol, incluyendo futuras líneas de trabajo. / [CA] Aquesta tesi doctoral se centra en l'estudi, implementació i aplicació de tècniques d'aprenentatge automàtic i estadística multivariant en l'emergent camp de l'analítica esportiva, concretament en el futbol. S'apliquen procediments comunament utilitzats i mètodes nous per a resoldre qu¿estions d'investigació en diferents àrees de l'anàlisi del futbol, tant en l'àmbit del rendiment esportiu com en l'econòmic. Les metodologies emprades en aquesta tesi enriqueixen les tècniques utilitzades fins al moment per a obtindre una visió global del comportament dels equips de futbol i pretenen ajudar al procés de presa de decisions. A més, la metodologia s'ha implementat utilitzant el programari estadístic lliure R i dades obertes, la qual cosa permet la replicabilitat dels resultats. Aquesta tesi doctoral pretén contribuir a la comprensió dels models d'aprenentatge automàtic i estadística multivariant per a la predicció analítica esportiva, comparant la seua capacitat predictiva i estudiant les variables que més influeixen en els resultats predictius d'aquests models. Així, sent el futbol un joc d'atzar on la sort juga un paper important, es proposen metodologies que ajuden a estudiar, comprendre i modelitzar la part objectiva d'aquest esport. Aquesta tesi s'estructura en cinc blocs, diferenciant cadascun en funció de la base de dades utilitzada per a aconseguir els objectius proposats. El primer bloc descriu les àrees d'estudi més comuns en l'analítica del futbol i les classifica en funció de les dades utilitzades. Aquesta part conté un estudi exhaustiu de l'estat de l'art de l'analítica del futbol. Així, es recopila part de la literatura existent en funció dels objectius aconseguits, conjuntament amb una revisió dels mètodes estadístics aplicats. Aquests models són els pilars sobre els quals se sustenten els nous procediments ací proposats. El segon bloc consta de dos capítols que estudien el comportament dels equips que aconsegueixen la Lliga de Campions o l'Europa League, descendeixen a segona divisió o romanen a la meitat de la taula. Es proposen diverses tècniques d'aprenentatge automàtic i estadística multivariant per a predir la posició dels equips a final de temporada. Una vegada realitzada la predicció, se selecciona el model amb millor precisió predictiva per a estudiar les accions de joc que més discriminen entre posicions. A més, s'analitzen els avantatges de les tècniques proposades enfront dels mètodes clàssics utilitzats fins al moment. El tercer bloc consta d'un únic capítol en el qual es desenvolupa un codi de web scraping per a facilitar la recuperació d'una nova base de dades amb informació quantitativa de les accions de joc realitzades al llarg del temps en els partits de futbol. Aquest bloc se centra en la predicció dels resultats dels partits (victòria, empat o derrota) i proposa la combinació d'una tècnica d'aprenentatge automàtic, random forest, i la regressió Skellam, un mètode clàssic utilitzat habitualment per a predir la diferència de gols en el futbol. Finalment, es compara la precisió predictiva dels mètodes clàssics utilitzats fins ara amb els mètodes multivariants proposats. El quart bloc també comprén un únic capítol i pertany a l'àrea econòmica del futbol. En aquest capítol s'aplica un nou procediment per a desenvolupar indicadors que ajuden a predir els preus de traspàs. En concret, es mostra la importància de la popularitat a l'hora de calcular el valor de mercat dels jugadors, per la qual cosa aquest capítol proposa una nova metodologia per a la recollida d'informació sobre la popularitat dels jugadors. En el cinqué bloc es revelen els aspectes més rellevants d'aquesta tesi per a la investigació i l'analítica en el futbol, incloent-hi futures línies de treball. / [EN] This doctoral thesis focuses on studying, implementing, and applying machine learning and multivariate statistics techniques in the emerging field of sports analytics, specifically in football. Commonly used procedures and new methods are applied to solve research questions in different areas of football analytics, both in the field of sports performance and in the economic field. The methodologies used in this thesis enrich the techniques used so far to obtain a global vision of the behaviour of football teams and are intended to help the decision-making process. In addition, the methodology was implemented using the free statistical software R and open data, which allows for reproducibility of the results. This doctoral thesis aims to contribute to the understanding of the behaviour of machine learning and multivariate models for analytical sports prediction, comparing their predictive capacity and studying the variables that most influence the predictive results of these models. Thus, since football is a game of chance where luck plays an important role, this document proposes methodologies that help to study, understand, and model the objective part of this sport. This thesis is structured into five blocks, differentiating each according to the database used to achieve the proposed objectives. The first block describes the most common study areas in football analytics and classifies them according to the available data. This part contains an exhaustive study of football analytics state of the art. Thus, part of the existing literature is compiled based on the objectives achieved, with a review of the statistical methods applied. These methods are the pillars on which the new procedures proposed here are based. The second block consists of two chapters that study the behaviour of teams concerning the ranking at the end of the season: top (qualifying for the Champions League or Europa League), middle, or bottom (relegating to a lower division). Several machine learning and multivariate statistical techniques are proposed to predict the teams' position at the season's end. Once the prediction has been made, the model with the best predictive accuracy is selected to study the game actions that most discriminate between positions. In addition, the advantages of our proposed techniques compared to the classical methods used so far are analysed. The third block consists of a single chapter in which a web scraping code is developed to facilitate the retrieval of a new database with quantitative information on the game actions carried out over time in football matches. This block focuses on predicting match outcomes (win, draw, or loss) and proposing the combination of a machine learning technique, random forest, and Skellam regression model, a classical method commonly used to predict goal difference in football. Finally, the predictive accuracy of the classical methods used so far is compared with the proposed multivariate methods. The fourth block also comprises a single chapter and pertains to the economic football area. This chapter applies a novel procedure to develop indicators that help predict transfer fees. Specifically, it is shown the importance of popularity when calculating the players' market value, so this chapter is devoted to propose a new methodology for collecting players' popularity information. The fifth block reveals the most relevant aspects of this thesis for research and football analytics, including future lines of work. / Malagón Selma, MDP. (2023). Machine Learning and Multivariate Statistical Tools for Football Analytics [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/197630
77

Augmented Intelligence for Clinical Discovery: Implementing Outlier Analysis to Accelerate Disease Knowledge and Therapeutic Advancements in Preeclampsia and Other Hypertensive Disorders of Pregnancy

Janoudi, Ghayath 02 October 2023 (has links)
Clinical observations of individual patients are the cornerstones for furthering our understanding of the human body, diseases, and therapeutics. Traditionally, clinical observations were communicated through publishing case reports and case series. The effort of identifying and investigating unusual clinical observations has always rested on the shoulders of busy clinicians. To date, there has been little effort dedicated to increasing the efficiency of identifying unique and uncommon patient observations that may lead to valuable discoveries. In this thesis, we propose and implement an augmented intelligence framework to identify potential novel clinical observations by combining machine analytics through outlier analysis with the judgment of subject-matter experts. Preeclampsia is a significant cause of maternal and perinatal mortality and morbidity, and advances in its management have been slow. Considering the complex etiological nature of preeclampsia, clinical observations are essential in advancing our understanding of the disease and therapeutic approaches. Thus, the objectives and studies in this thesis aim to answer the hypothesis that using outlier analysis in preeclampsia-related medical data would lead to identifying previously uninvestigated clinical cases with new clinical insight. This thesis combines three articles published or submitted for publication in peer-reviewed journals. The first article (published) is a systematic review examining the extent to which case reports and case series in preeclampsia have contributed new knowledge or discoveries. We report that under one-third of the identified case reports and case series presented new knowledge. In our second article (submitted for publication), we provide an overview of outlier analysis and introduce the framework of augmented intelligence using our proposed extreme misclassification contextual outlier analysis approach. Furthermore, we conduct a systematic review of obstetrics-related research that used outlier analysis to answer scientific questions. Our systematic review findings indicate that such use is in its infancy. In our third article (published), we implement the proposed augmented intelligence framework using two different outlier analysis methods on two independent datasets from separate studies in preeclampsia and hypertensive disorders of pregnancy. We identify several clinical observations as potential novelties, thus supporting the feasibility and applicability of outlier analysis to accelerate clinical discovery.
78

Forecasting Stock Prices Using an Auto Regressive Exogenous model

Hjort, Måns, Andersson, Lukas January 2023 (has links)
This project aimed to evaluate the effectiveness of the Auto Regressive Exogenous(ARX) model in forecasting stock prices and contribute to research on statisticalmodels in predicting stock prices. An ARX model is a type of linear regression modelused in time series analysis to forecast future values based on past values and externalinput signals. In this study, the ARX model was used to forecast the closing pricesof stocks listed on the OMX Stockholm 30 (OMXS30*) excluding Essity, Evolution,and Sinch, using historical data from 2016-01-01 to 2020-01-01 obtained from YahooFinance. The model was trained using the least squares approach with a control signal that filtersoutliers in the data. This was done by modeling the ARX model using optimizationtheory and then solving that optimization problem using Gurobi OptimizationSoftware. Subsequently, the accuracy of the model was tested by predicting prices in aperiod based on past values and the exogenous input variable. The results indicated that the ARX model was not suitable for predicting stock priceswhile considering short time periods.
79

Dinâmica populacional e avaliação do estoque do camarão rosa (Farfantepenaeus subtilis Pérez-Farfante 1967) na plataforma continental amazônica brasileira / Population dynamics and stock assessment of the brown shrimp, Farfantepenaeus subtilis, (Pérez-Farfante 1967) in the Amazon continental shelf

Aragão, José Augusto Negreiros 12 September 2012 (has links)
O camarão rosa (Farfantepenaeus subtilis) explotado pela pesca industrial na plataforma continental amazônica brasileira possui um ciclo de vida curto, mas complexo, habitando áreas oceânicas, mais ao norte da área de ocorrência, na fase adulta e larval, e áreas estuarinas e lagunares na fase de pós-larva e juvenil. O período de maior intensidade de reprodução se estende de maio a setembro e logo após a reprodução as larvas eclodem e iniciam sua migração para áreas costeiras, passando por diversas fases, onde se assentam e residem principalmente entre junho e outubro. A partir de setembro até janeiro do ano seguinte é maior a intensidade de recrutamento de juvenis às áreas oceânicas, onde passam a amadurecer e, a partir de dezembro, começam a ser capturados pela pesca industrial. A maior abundância da população adulta em termos de biomassa vai de março a agosto quando também se verificam as maiores capturas. As fêmeas crescem mais que os machos e estão presentes sempre em maior proporção nas capturas (61%). Os comprimentos assintóticos foram estimados em 231 mm ( k = 1,6 \'ano POT.-1\') e 205 mm (k = 0,94 \'ano POT.-1\'), para fêmeas e machos respectivamente. A população apresenta taxa de mortalidade natural relativamente elevada, 2,53 \'ano POT.-1\' para fêmeas e 1,83 \'ano POT.-1\' para machos, sendo observadas acentuadas flutuações de recrutamento e abundância, com evidências de que são fortemente governadas pelas condições ambientais. O estoque vem sendo explotado em níveis moderados nos anos recentes (E = 0,45), embora tenha sofrido elevadas taxas de explotação na década de 80, o que levou a uma redução do tamanho da população. O rendimento máximo sustentável, considerado uma média de longo prazo, foi estimado em 4.032 toneladas de cauda por ano, para um esforço de pesca de 19.370 dias de mar. Nos últimos anos, se observa uma tendência de recuperação da biomassa populacional, mas com as oscilações anuais características da espécie. A vazão do rio Amazonas é o fator ambiental que governa com mais intensidade as condições do ambiente costeiro na região e verificou-se que suas flutuações estão correlacionadas a alterações na abundância da população da espécie. Postula-se que o aporte e sobrevivência das larvas e pós-larvas no ambiente costeiro seja influenciada pela intensidade da vazão do rio. O período em que se assentam nos berçários na zona costeira coincide com a estação de vazante do rio, sendo a sobrevivência favorecida por vazões abaixo da média e vice-versa. Portanto, medidas de ordenamento voltadas para o uso sustentável do recurso devem estar associadas ao conhecimento das condições ambientais nesta fase, bem como a estudos sobre a abundância de pós-larvas e juvenis na faixa costeira. / The brown shrimp (Farfantepenaeus subtilis) exploited by the industrial fishery on the continental shelf of the Brazilian Amazon has a short but complex life cyele, inhabiting oceanic areas, at the north of the area of occurrence, during the adult and larval stages, and estuarine areas and lagoons in post-larval and juvenile. The period of highest intensity of reproduction extends from May to September and soon after the hatch, the larvae start their migration to coastal areas, passing through several stages, where they settle and remain resident between June and October. From September to January of the following year the intensity of recruitment to ocean areas is higher, and once there they start to mature and are caught by the industrial fishery from December on. The highest abundance of the adult population in terms of biomass is observed from March to August when the largest catches also occur. Females grow larger than males and are always present in greater proportion in catches (61%). The asymptotic lengths were estimated at 231 mm (k = 1.6 \'year POT.-1\') and 205 mm (k = 0.94 \'year POT.-1\') for females and males respectively. The population has a natural mortality rate relatively high, 2.53 \'year POT.-1\' for females and 1.83 \'years POT.-1\' for males, and pronounced fluctuations in recruitment and abundance are observed, with evidence of being strongly governed by environmental conditions. The stock has been exploited at moderate levels in recent years (E = 0.45), although it has suffered high rates of exploitation in the 80\'s, which led to a reduction in population size. The maximum sustainable yield, considered a long-term average, was estimated at 4,032 ton of tail per year for a fishing effort of 19,370 days at sea. In recent years, it is observed a tendency of recovering of the population biomass, but annual fluctuations are characteristics of the species. The flow of the Amazon River is the main environmental facto r that governs the conditions of the coastal environment in the region and it was found that it is correlated with the fluctuatícn of the brown shrimp population abundance. It is postulated that the uptake and survival of larvae and post larvae in the coastal environment is lnfluenced by the intensity of river flow, The period during which they settle at the nurseries in the coastal zone coincides with the dry season and their survival is favored when the flow of the river is below the average, and vice versa. Therefore, management measures aimed at sustainable use of the resource must be associated with the knowledge of environmental conditions during this phase, as well as studies on the abundance of post-larvae and juveniles in the coastal zone.
80

Modélisation automatique et simulation de parcours de soins à partir de bases de données de santé / Process discovery, analysis and simulation of clinical pathways using health-care data

Prodel, Martin 10 April 2017 (has links)
Les deux dernières décennies ont été marquées par une augmentation significative des données collectées dans les systèmes d'informations. Cette masse de données contient des informations riches et peu exploitées. Cette réalité s’applique au secteur de la santé où l'informatisation est un enjeu pour l’amélioration de la qualité des soins. Les méthodes existantes dans les domaines de l'extraction de processus, de l'exploration de données et de la modélisation mathématique ne parviennent pas à gérer des données aussi hétérogènes et volumineuses que celles de la santé. Notre objectif est de développer une méthodologie complète pour transformer des données de santé brutes en modèles de simulation des parcours de soins cliniques. Nous introduisons d'abord un cadre mathématique dédié à la découverte de modèles décrivant les parcours de soin, en combinant optimisation combinatoire et Process Mining. Ensuite, nous enrichissons ce modèle par l’utilisation conjointe d’un algorithme d’alignement de séquences et de techniques classiques de Data Mining. Notre approche est capable de gérer des données bruitées et de grande taille. Enfin, nous proposons une procédure pour la conversion automatique d'un modèle descriptif des parcours de soins en un modèle de simulation dynamique. Après validation, le modèle obtenu est exécuté pour effectuer des analyses de sensibilité et évaluer de nouveaux scénarios. Un cas d’étude sur les maladies cardiovasculaires est présenté, avec l’utilisation de la base nationale des hospitalisations entre 2006 et 2015. La méthodologie présentée dans cette thèse est réutilisable dans d'autres aires thérapeutiques et sur d'autres sources de données de santé. / During the last two decades, the amount of data collected in Information Systems has drastically increased. This large amount of data is highly valuable. This reality applies to health-care where the computerization is still an ongoing process. Existing methods from the fields of process mining, data mining and mathematical modeling cannot handle large-sized and variable event logs. Our goal is to develop an extensive methodology to turn health data from event logs into simulation models of clinical pathways. We first introduce a mathematical framework to discover optimal process models. Our approach shows the benefits of combining combinatorial optimization and process mining techniques. Then, we enrich the discovered model with additional data from the log. An innovative combination of a sequence alignment algorithm and of classical data mining techniques is used to analyse path choices within long-term clinical pathways. The approach is suitable for noisy and large logs. Finally, we propose an automatic procedure to convert static models of clinical pathways into dynamic simulation models. The resulting models perform sensitivity analyses to quantify the impact of determinant factors on several key performance indicators related to care processes. They are also used to evaluate what-if scenarios. The presented methodology was proven to be highly reusable on various medical fields and on any source of event logs. Using the national French database of all the hospital events from 2006 to 2015, an extensive case study on cardiovascular diseases is presented to show the efficiency of the proposed framework.

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