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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.
241

Adaptivní model pro simulaci znečištění ovzduší / Adaptive Model for Simulation of Atmospheric Pollution

Pazúriková, Jana January 2012 (has links)
Air pollution harms the environment and human welfare. Computer models and their simulation are useful tools for deeper understanding of processes behind as they quite accurately represent the dispersion and transformation of pollutants with advection diffusion equation or by other concepts. Current models give valid results only to constrained cases of initial conditions. The general model combining the several specific models which is able to change according to input parametres and improve with training is proposed. The adaptiveness of the system is provided by decision tree as data structure with information for selection and combination process and genetic algorithm as optimization method for adjusting the tree. The evaluation of implemented system proves that the combination of models gives better results than models themselves. Even with simple specific models, the system has achieved results comparable to state-of-art models of air pollution.
242

Personalizovaná webová aplikace / Personalized Web Application

Hradil, Luděk January 2010 (has links)
This thesis deals with the extension of the bachelor's thesis Movie Database. I focus on the practical application of data mining as well as the personalization of this information system. In data mining, I will use the data accrued during the operation site. The introduction summarizes the concepts of data mining. In the second section  outlines new developments in web applications followed by an overview and description of the new site's features.  The last chapters are devoted to  the description of the design and the implementation of data mining techniques. The conclusion gives the achieved results.
243

A comparative study on artificial neural networks and random forests for stock market prediction

Varatharajah, Thujeepan, Victor, Eriksson January 2016 (has links)
This study investigates the predictive performance of two different machine learning (ML) models on the stock market and compare the results. The chosen models are based on artificial neural networks (ANN) and random forests (RF). The models are trained on two separate data sets and the predictions are made on the next day closing price. The input vectors of the models consist of 6 different financial indicators which are based on the closing prices of the past 5, 10 and 20 days. The performance evaluation are done by analyzing and comparing such values as the root mean squared error (RMSE) and mean average percentage error (MAPE) for the test period. Specific behavior in subsets of the test period is also analyzed to evaluate consistency of the models. The results showed that the ANN model performed better than the RF model as it throughout the test period had lower errors compared to the actual prices and thus overall made more accurate predictions. / Denna studie undersöker hur väl två olika modeller inom maskininlärning (ML) kan förutspå aktiemarknaden och jämför sedan resultaten av dessa. De valda modellerna baseras på artificiella neurala nätverk (ANN) samt random forests (RF). Modellerna tränas upp med två separata datamängder och prognoserna sker på nästföljande dags stängningskurs. Indatan för modellerna består av 6 olika finansiella nyckeltal som är baserade på stängningskursen för de senaste 5, 10 och 20 dagarna. Prestandan utvärderas genom att analysera och jämföra värden som root mean squared error (RMSE) samt mean average percentage error (MAPE) för testperioden. Även specifika trender i delmängder av testperioden undersöks för att utvärdera följdriktigheten av modellerna. Resultaten visade att ANN-modellen presterade bättre än RF-modellen då den sett över hela testperioden visade mindre fel jämfört med de faktiska värdena och gjorde därmed mer träffsäkra prognoser.
244

Designing and Assessing New Educational Pedagogies in Biology and Health Promotion

Cook, Kristian Ciarah 02 April 2020 (has links)
Recent developments in educational research raise important questions about the design of learning environments—questions that suggest the value of rethinking what is taught, how it is taught, and how is it assessed. During the past few decades, STEM disciplines began formally recognizing and integrating discipline-based education research (DBER) into their research programs to improve STEM education. One of the less literature-affluent areas of DBER addresses curriculum order and design appertaining to concept types and the order in which we teach those concepts. As educational researchers, we pose the question: does content order matter? In this project we designed, implemented and analyzed a concrete-to-abstract curriculum as a way of teaching and learning that not only builds off what students already know but how their intellect develops throughout the learning process. This semester-long curriculum design is scientifically supported and provides a learning environment aimed to not only building a student’s declarative knowledge of the subject but procedural knowledge as well and a way of developing scientific reasoning skills. This design also aimed at enhancing a student’s ability to make connections between biological concepts despite being classified as different biological concept types (e.g. descriptive, hypothetical, and theoretical concepts) as described by Lawson et al (2000). The reasoning behind and development of this project was based from Jean Piaget’s proposed stages of intellectual development, which supports the concrete-to-abstract theory. We found that, when compared to a traditional biology course (abstract-to-concrete in terms of content order), a concrete-to-abstract order of content resulted in significantly higher biological declarative knowledge and ability to make concept connections. While we failed to detect a significant difference between the two courses in terms of how quickly scientific reasoning skills are developed or how students’ scores on scientific reasoning skill assessments, the concrete-to-abstract course did show significantly higher gains in reasoning between the start and end of the semester. In addition to this project, a significant amount of time was also allocated to the design and evaluation of a health promotion and education program in Samoa. We developed a program which centered on a principal-run caregiver meeting as a means to expand health promotion and prevention efforts concerning Rheumatic Heart Disease, which is a significant cause of child morbidity and mortality in Samoa. We found that training principals on how to inform their student’s caregivers was an effective way to increase RHD awareness and disseminate correct health information including what to do if their child presents with a sore throat.
245

Aplicación de Data Science en la pequeña empresa, caso: Pollería Mister Pollo

Baldeón Maraví, Brian, Fukushima Castillo, Hugo Kenji, Ochante Quispe, Milagros Karina, Quevedo Trujillo, Haedly Victoria, Tejada Alarcón, Ernesto Rosendo 14 July 2021 (has links)
El presente trabajo tiene como finalidad aplicar los conocimientos y técnicas impartidas durante los tres cursos de Ciencia de Datos. Específicamente identificar y utilizar las variables encontradas en el negocio para determinar un modelo que permita una mayor permanencia del personal en la empresa Mister Pollo. En ese contexto, la investigación se apoyará en la metodología de ciencia de datos de IBM, la cual inicia con la fase de comprensión del negocio para identificar el problema de la organización, analizando sus fortalezas y debilidades; así como la fase de recopilación y preparación de los datos, análisis, interpretación, modelado y evaluación de la data. Asimismo, el tipo de investigación que se emplea es mixto, pues en la fase inicial tiene un enfoque descriptivo que permite entender la importancia de las variables utilizadas. En la segunda fase, el enfoque se vuelve predictivo gracias a la utilización de una técnica de aprendizaje supervisado, en este caso, el modelo de árbol de decisión para la determinación de una herramienta que permita evaluar la mayor permanencia de trabajadores en el restaurante. Esto permitirá que el Gerente General de la empresa pueda elaborar un plan de acción para poder controlar y minimizar la rotación del personal, considerando diferentes escenarios, perfiles y necesidades de la empresa. Finalmente, en la conclusión de este proyecto se evaluarán los hallazgos en el modelo seleccionado para verificar que responden a los objetivos planteados por el Gerente de la empresa Míster Pollo en coordinación con el equipo de trabajo. / The purpose of this work is to apply the knowledge and techniques taught during the three Data Science courses. Specifically, to identify and use the variables found in the business to determine a model that allows a greater permanence of the personnel in the company Mister Pollo. In this context, the research will be supported by IBM's data science methodology, which begins with the phase of understanding the business to identify the organization's problem, analyzing its strengths and weaknesses; as well as the phase of data collection and preparation, analysis, interpretation, modeling and evaluation of the data. Likewise, the type of research used is mixed, since in the initial phase it has a descriptive approach that allows understanding the importance of the variables used. In the second phase, the approach becomes predictive thanks to the use of a supervised learning technique, in this case, the decision tree model for the determination of a tool to evaluate the greater permanence of workers in the restaurant. This will allow the General Manager of the company to develop an action plan to control and minimize staff turnover, considering different scenarios, profiles and needs of the company. Finally, at the conclusion of this project, the findings of the selected model will be evaluated to verify that they respond to the objectives set by the Manager of the company Míster Pollo in coordination with the work team. / Trabajo de investigación
246

Dolovací moduly systému pro dolování z dat na platformě NetBeans / Mining Modules of Data Mining System on NetBeans Platform

Henkl, Tomáš January 2009 (has links)
The master's thesis deals with the knowledge discover in databases and with the extending of the data mining systems in the Oracle environment developed at the VUT FIT. The system kernel conception incorporates an interface that enables the adding of data mining modules. The objective of the thesis is to learn this interface and implement and embed the data mining module for decision-tree classification into the application. In addition, the thesis compares the application with similar commercial product SAS Enterprise Miner
247

[en] THE USE OF DECISION TREES, NEURAL NETWORKS AND KNN SYSTEMS TO AUTOMATICALLY IDENTIFY BOX & JENKINS NON-SEASONAL AND SEASONAL STRUCTURES / [pt] UMA APLICAÇÃO DE ÁRVORES DE DECISÃO, REDES NEURAIS E KNN PARA A IDENTIFICAÇÃO DE MODELOS ARMA NÃO-SAZONAIS E SAZONAIS

LUIZA MARIA OLIVEIRA DA SILVA 19 December 2005 (has links)
[pt] A metodologia Box & Jenkins tem sido mais utilizada para fazer previsões do que outros métodos até então. Alguns analistas têm relutado, entretanto, em usar esta metodologia, em parte porque a identificação da estrutura adequada é uma tarefa complexa. O reconhecimento tanto dos padrões de comportamento das funções de autocorrelação quanto da autocorrelação parcial (teórica/estimada) dependem da série temporal através da qual é possível extraí-las. Uma vez obtidos os resultados, pode-se inferir qual o tipo de estrutura Box & Jenkins adequada para a série. A proposta do trabalho é desenvolver três novas metodologias de identificação automática das estruturas Box & Jenkins ARMA simples e/ou sazonais, identificar os filtros sazonal e linear da série de uma forma menos complexa. A primeira metodologia utiliza árvores de decisão, a segunda, redes neurais e a terceira, K-Nearest Neighbor (KNN). A estas metodologias serão utilizadas as estruturas Box & Jenkins sazonais de períodos 3, 4, 6 e 12 e não sazonais. Os resultados são aplicados a séries simuladas, bem como a séries reais. Como comparação, utilizou-se o método automático de identificação proposto no software FPW-XE. / [en] The Box & Jenkins is the most popular forecasting technique. However, some researchers have not embraced it because the identification of its structure is highly complex. The process of proper characterizing the properties of both autocorrelation functions and partial correlation (theoretical or estimated) depends on the time series from which they are being obtained. Given the results in question, it is possible to infer the proper Box & Jenkins structure for the time series being studied. For the reasons above, the goal of this dissertation is to develop three new methodologies to identifying, in an automatic fashion, the Box & Jenkins structure of an ARMA series. The methodologies identify, in a simpler manner, both the seasonal and linear filters of the series. The first methodology applies the decision tree. The second applies the neural networks. The third applies the K-Nearest Neighbor (KNN). In each of them the Box & Jenkins seasonal structures of 3, 4, 6 and 12 periods were used, as well as the nonseasonal structure. The results are applied to simulated and actual series. For comparison purposes, the automatic identification procedure of the software FPW-XE is also used.
248

Activity Intent Recognition of the Torso Based on Surface Electromyography and Inertial Measurement Units

Zhang, Zhe 01 January 2013 (has links) (PDF)
This thesis presents an activity mode intent recognition approach for safe, robust and reliable control of powered backbone exoskeleton. The thesis presents the background and a concept for a powered backbone exoskeleton that would work in parallel with a user. The necessary prerequisites for the thesis are presented, including the collection and processing of surface electromyography signals and inertial sensor data to recognize the user’s activity. The development of activity mode intent recognizer was described based on decision tree classification in order to leverage its computational efficiency. The intent recognizer is a high-level supervisory controller that belongs to a three-level control structure for a powered backbone exoskeleton. The recognizer uses surface electromyography and inertial signals as the input and CART (classification and regression tree) as the classifier. The experimental results indicate that the recognizer can extract the user’s intent with minimal delay. The approach achieves a low recognition error rate and a user-unperceived latency by using sliding overlapped analysis window. The approach shows great potential for future implementation on a prototype backbone exoskeleton.
249

Maskininlärning med konform förutsägelse för prediktiva underhållsuppgifter i industri 4.0 / Machine Learning with Conformal Prediction for Predictive Maintenance tasks in Industry 4.0 : Data-driven Approach

Liu, Shuzhou, Mulahuko, Mpova January 2023 (has links)
This thesis is a cooperation with Knowit, Östrand \& Hansen, and Orkla. It aimed to explore the application of Machine Learning and Deep Learning models with Conformal Prediction for a predictive maintenance situation at Orkla. Predictive maintenance is essential in numerous industrial manufacturing scenarios. It can help to reduce machine downtime, improve equipment reliability, and save unnecessary costs.  In this thesis, various Machine Learning and Deep Learning models, including Decision Tree, Random Forest, Support Vector Regression, Gradient Boosting, and Long short-term memory, are applied to a real-world predictive maintenance dataset. The Orkla dataset was originally planned to use in this thesis project. However, due to some challenges met and time limitations, one NASA C-MAPSS dataset with a similar data structure was chosen to study how Machine Learning models could be applied to predict the remaining useful lifetime (RUL) in manufacturing. Besides, conformal prediction, a recently developed framework to measure the prediction uncertainty of Machine Learning models, is also integrated into the models for more reliable RUL prediction.  The thesis project results show that both the Machine Learning and Deep Learning models with conformal prediction could predict RUL closer to the true RUL while LSTM outperforms the Machine Learning models. Also, the conformal prediction intervals provide informative and reliable information about the uncertainty of the predictions, which can help inform personnel at factories in advance to take necessary maintenance actions.  Overall, this thesis demonstrates the effectiveness of utilizing machine learning and Deep Learning models with Conformal Prediction for predictive maintenance situations. Moreover, based on the modeling results of the NASA dataset, some insights are discussed on how to transfer these experiences into Orkla data for RUL prediction in the future.
250

[en] A METHOD FOR INTERPRETING CONCEPT DRIFTS IN A STREAMING ENVIRONMENT / [pt] UM MÉTODO PARA INTERPRETAÇÃO DE MUDANÇAS DE REGIME EM UM AMBIENTE DE STREAMING

JOAO GUILHERME MATTOS DE O SANTOS 10 August 2021 (has links)
[pt] Em ambientes dinâmicos, os modelos de dados tendem a ter desempenho insatisfatório uma vez que a distribuição subjacente dos dados muda. Este fenômeno é conhecido como Concept Drift. Em relação a este tema, muito esforço tem sido direcionado ao desenvolvimento de métodos capazes de detectar tais fenômenos com antecedência suficiente para que os modelos possam se adaptar. No entanto, explicar o que levou ao drift e entender suas consequências ao modelo têm sido pouco explorado pela academia. Tais informações podem mudar completamente a forma como adaptamos os modelos. Esta dissertação apresenta uma nova abordagem, chamada Detector de Drift Interpretável, que vai além da identificação de desvios nos dados. Ele aproveita a estrutura das árvores de decisão para prover um entendimento completo de um drift, ou seja, suas principais causas, as regiões afetadas do modelo e sua severidade. / [en] In a dynamic environment, models tend to perform poorly once the underlying distribution shifts. This phenomenon is known as Concept Drift. In the last decade, considerable research effort has been directed towards developing methods capable of detecting such phenomena early enough so that models can adapt. However, not so much consideration is given to explain the drift, and such information can completely change the handling and understanding of the underlying cause. This dissertation presents a novel approach, called Interpretable Drift Detector, that goes beyond identifying drifts in data. It harnesses decision trees’ structure to provide a thorough understanding of a drift, i.e., its principal causes, the affected regions of a tree model, and its severity. Moreover, besides all information it provides, our method also outperforms benchmark drift detection methods in terms of falsepositive rates and true-positive rates across several different datasets available in the literature.

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