Spelling suggestions: "subject:"aynthetic data generation"" "subject:"asynthetic data generation""
11 |
[en] AN APPROACH BASED ON INTERACTIVE MACHINE LEARNING AND NATURAL INTERACTION TO SUPPORT PHYSICAL REHABILITATION / [pt] UMA ABORDAGEM BASEADA NO APRENDIZADO DE MÁQUINA INTERATIVO E INTERAÇÃO NATURAL PARA APOIO À REABILITAÇÃO FÍSICAJESSICA MARGARITA PALOMARES PECHO 10 August 2021 (has links)
[pt] A fisioterapia visa melhorar a funcionalidade física das pessoas, procurando
atenuar as incapacidades causadas por alguma lesão, distúrbio ou
doença. Nesse contexto, diversas tecnologias computacionais têm sido desenvolvidas
com o intuito de apoiar o processo de reabilitação, como as tecnologias
adaptáveis para o usuário final. Essas tecnologias possibilitam ao fisioterapeuta
adequar aplicações e criarem atividades com características personalizadas de
acordo com as preferências e necessidades de cada paciente. Nesta tese é proposta
uma abordagem de baixo custo baseada no aprendizado de máquina
interativo (iML - Interactive Machine Learning) que visa auxiliar os fisioterapeutas
a criarem atividades personalizadas para seus pacientes de forma fácil
e sem a necessidade de codificação de software, a partir de apenas alguns exemplos
em vídeo RGB (capturadas por uma câmera de vídeo digital) Para tal,
aproveitamos a estimativa de pose baseada em aprendizado profundo para rastrear,
em tempo real, as articulações-chave do corpo humano a partir de dados
da imagem. Esses dados são processados como séries temporais por meio do algoritmo
Dynamic Time Warping em conjunto com com o algoritmo K-Nearest
Neighbors para criar um modelo de aprendizado de máquina. Adicionalmente,
usamos um algoritmo de detecção de anomalias com o intuito de avaliar automaticamente
os movimentos. A arquitetura de nossa abordagem possui dois
módulos: um para o fisioterapeuta apresentar exemplos personalizados a partir
dos quais o sistema cria um modelo para reconhecer esses movimentos; outro
para o paciente executar os movimentos personalizados enquanto o sistema
avalia o paciente. Avaliamos a usabilidade de nosso sistema com fisioterapeutas
de cinco clínicas de reabilitação. Além disso, especialistas avaliaram clinicamente
nosso modelo de aprendizado de máquina. Os resultados indicam que
a nossa abordagem contribui para avaliar automaticamente os movimentos dos
pacientes sem monitoramento direto do fisioterapeuta, além de reduzir o tempo
necessário do especialista para treinar um sistema adaptável. / [en] Physiotherapy aims to improve the physical functionality of people, seeking
to mitigate the disabilities caused by any injury, disorder or disease. In
this context, several computational technologies have been developed in order
to support the rehabilitation process, such as the end-user adaptable technologies.
These technologies allow the physiotherapist to adapt applications and
create activities with personalized characteristics according to the preferences
and needs of each patient. This thesis proposes a low-cost approach based on
interactive machine learning (iML) that aims to help physiotherapists to create
personalized activities for their patients easily and without the need for
software coding, from just a few examples in RGB video (captured by a digital
video camera). To this end, we take advantage of pose estimation based on deep
learning to track, in real time, the key joints of the human body from image
data. This data is processed as time series using the Dynamic Time Warping
algorithm in conjunction with the K-Nearest Neighbors algorithm to create a
machine learning model. Additionally, we use an anomaly detection algorithm
in order to automatically assess movements. The architecture of our approach
has two modules: one for the physiotherapist to present personalized examples
from which the system creates a model to recognize these movements; another
to the patient performs personalized movements while the system evaluates
the patient. We assessed the usability of our system with physiotherapists
from five rehabilitation clinics. In addition, experts have clinically evaluated
our machine learning model. The results indicate that our approach contributes
to automatically assessing patients movements without direct monitoring by
the physiotherapist, in addition to reducing the specialist s time required to
train an adaptable system.
|
12 |
Multivariate Time Series Data Generation using Generative Adversarial Networks : Generating Realistic Sensor Time Series Data of Vehicles with an Abnormal Behaviour using TimeGANNord, Sofia January 2021 (has links)
Large datasets are a crucial requirement to achieve high performance, accuracy, and generalisation for any machine learning task, such as prediction or anomaly detection, However, it is not uncommon for datasets to be small or imbalanced since gathering data can be difficult, time-consuming, and expensive. In the task of collecting vehicle sensor time series data, in particular when the vehicle has an abnormal behaviour, these struggles are present and may hinder the automotive industry in its development. Synthetic data generation has become a growing interest among researchers in several fields to handle the struggles with data gathering. Among the methods explored for generating data, generative adversarial networks (GANs) have become a popular approach due to their wide application domain and successful performance. This thesis focuses on generating multivariate time series data that are similar to vehicle sensor readings from the air pressures in the brake system of vehicles with an abnormal behaviour, meaning there is a leakage somewhere in the system. A novel GAN architecture called TimeGAN was trained to generate such data and was then evaluated using both qualitative and quantitative evaluation metrics. Two versions of this model were tested and compared. The results obtained proved that both models learnt the distribution and the underlying information within the features of the real data. The goal of the thesis was achieved and can become a foundation for future work in this field. / När man applicerar en modell för att utföra en maskininlärningsuppgift, till exempel att förutsäga utfall eller upptäcka avvikelser, är det viktigt med stora dataset för att uppnå hög prestanda, noggrannhet och generalisering. Det är dock inte ovanligt att dataset är små eller obalanserade eftersom insamling av data kan vara svårt, tidskrävande och dyrt. När man vill samla tidsserier från sensorer på fordon är dessa problem närvarande och de kan hindra bilindustrin i dess utveckling. Generering av syntetisk data har blivit ett växande intresse bland forskare inom flera områden som ett sätt att hantera problemen med datainsamling. Bland de metoder som undersökts för att generera data har generative adversarial networks (GANs) blivit ett populärt tillvägagångssätt i forskningsvärlden på grund av dess breda applikationsdomän och dess framgångsrika resultat. Denna avhandling fokuserar på att generera flerdimensionell tidsseriedata som liknar fordonssensoravläsningar av lufttryck i bromssystemet av fordon med onormalt beteende, vilket innebär att det finns ett läckage i systemet. En ny GAN modell kallad TimeGAN tränades för att genera sådan data och utvärderades sedan både kvalitativt och kvantitativt. Två versioner av denna modell testades och jämfördes. De erhållna resultaten visade att båda modellerna lärde sig distributionen och den underliggande informationen inom de olika signalerna i den verkliga datan. Målet med denna avhandling uppnåddes och kan lägga grunden för framtida arbete inom detta område.
|
13 |
Privacy-preserving Synthetic Data Generation for Healthcare Planning / Sekretessbevarande syntetisk generering av data för vårdplaneringYang, Ruizhi January 2021 (has links)
Recently, a variety of machine learning techniques have been applied to different healthcare sectors, and the results appear to be promising. One such sector is healthcare planning, in which patient data is used to produce statistical models for predicting the load on different units of the healthcare system. This research introduces an attempt to design and implement a privacy-preserving synthetic data generation method adapted explicitly to patients’ health data and for healthcare planning. A Privacy-preserving Conditional Generative Adversarial Network (PPCGAN) is used to generate synthetic data of Healthcare events, where a well-designed noise is added to the gradients in the training process. The concept of differential privacy is used to ensure that adversaries cannot reveal the exact training samples from the trained model. Notably, the goal is to produce digital patients and model their journey through the healthcare system. / Nyligen har en mängd olika maskininlärningstekniker tillämpats på olika hälso- och sjukvårdssektorer, och resultaten verkar lovande. En sådan sektor är vårdplanering, där patientdata används för att ta fram statistiska modeller för att förutsäga belastningen på olika enheter i sjukvården. Denna forskning introducerar ett försök att utforma och implementera en sekretessbevarande syntetisk datagenereringsmetod som uttryckligen anpassas till patienters hälsodata och för vårdplanering. Ett sekretessbevarande villkorligt generativt kontradiktoriskt nätverk (PPCGAN) används för att generera syntetisk data från hälsovårdshändelser, där ett väl utformat brus läggs till gradienterna i träningsprocessen. Begreppet differentiell integritet används för att säkerställa att motståndare inte kan avslöja de exakta träningsproven från den tränade modellen. Målet är särskilt att producera digitala patienter och modellera deras resa genom sjukvården.
|
14 |
Augmenting High-Dimensional Data with Deep Generative Models / Högdimensionell dataaugmentering med djupa generativa modellerNilsson, Mårten January 2018 (has links)
Data augmentation is a technique that can be performed in various ways to improve the training of discriminative models. The recent developments in deep generative models offer new ways of augmenting existing data sets. In this thesis, a framework for augmenting annotated data sets with deep generative models is proposed together with a method for quantitatively evaluating the quality of the generated data sets. Using this framework, two data sets for pupil localization was generated with different generative models, including both well-established models and a novel model proposed for this purpose. The unique model was shown both qualitatively and quantitatively to generate the best data sets. A set of smaller experiments on standard data sets also revealed cases where this generative model could improve the performance of an existing discriminative model. The results indicate that generative models can be used to augment or replace existing data sets when training discriminative models. / Dataaugmentering är en teknik som kan utföras på flera sätt för att förbättra träningen av diskriminativa modeller. De senaste framgångarna inom djupa generativa modeller har öppnat upp nya sätt att augmentera existerande dataset. I detta arbete har ett ramverk för augmentering av annoterade dataset med hjälp av djupa generativa modeller föreslagits. Utöver detta så har en metod för kvantitativ evaulering av kvaliteten hos genererade data set tagits fram. Med hjälp av detta ramverk har två dataset för pupillokalisering genererats med olika generativa modeller. Både väletablerade modeller och en ny modell utvecklad för detta syfte har testats. Den unika modellen visades både kvalitativt och kvantitativt att den genererade de bästa dataseten. Ett antal mindre experiment på standardiserade dataset visade exempel på fall där denna generativa modell kunde förbättra prestandan hos en existerande diskriminativ modell. Resultaten indikerar att generativa modeller kan användas för att augmentera eller ersätta existerande dataset vid träning av diskriminativa modeller.
|
15 |
Complex Vehicle Modeling: A Data Driven ApproachAlexander Christopher Schoen (8068376) 31 January 2022 (has links)
<div> This thesis proposes an artificial neural network (NN) model to predict fuel consumption in heavy vehicles. The model uses predictors derived from vehicle speed, mass, and road grade. These variables are readily available from telematics devices that are becoming an integral part of connected vehicles. The model predictors are aggregated over a fixed distance traveled (i.e., window) instead of fixed time interval. It was found that 1km windows is most appropriate for the vocations studied in this thesis. Two vocations were studied, refuse and delivery trucks.</div><div><br></div><div> The proposed NN model was compared to two traditional models. The first is a parametric model similar to one found in the literature. The second is a linear regression model that uses the same features developed for the NN model.</div><div><br></div><div> The confidence level of the models using these three methods were calculated in order to evaluate the models variances. It was found that the NN models produce lower point-wise error. However, the stability of the models are not as high as regression models. In order to improve the variance of the NN models, an ensemble based on the average of 5-fold models was created. </div><div><br></div><div> Finally, the confidence level of each model is analyzed in order to understand how much error is expected from each model. The mean training error was used to correct the ensemble predictions for five K-Fold models. The ensemble K-fold model predictions are more reliable than the single NN and has lower confidence interval than both the parametric and regression models.</div>
|
Page generated in 0.178 seconds