Sökning: "Wavelet transform"

Visar resultat 1 - 5 av 73 uppsatser innehållade orden Wavelet transform.

  1. 1. Data Assimilation for Systems with Multiple Timescales

    Kandidat-uppsats, KTH/Skolan för teknikvetenskap (SCI)

    Författare :Dan Vicente Ihanus; [2023]
    Nyckelord :Mathematics; Partial Differential Equations; Numerical analysis; Data assimilation; Numerical weather prediction; Ensemble Kalman Filter;

    Sammanfattning : This text provides an overview of problems in the field of data assimilation. We explore the possibility of recreating unknown data by continuously inserting known data into certain dynamical systems, under certain regularity assumptions. LÄS MER

  3. 2. Unsupervised Detection of Interictal Epileptiform Discharges in Routine Scalp EEG : Machine Learning Assisted Epilepsy Diagnosis

    Uppsats för yrkesexamina på avancerad nivå, Uppsala universitet/Avdelningen Vi3

    Författare :Shuai Shao; [2023]
    Nyckelord :EEG; electroencephalography; IED; interictal epileptiform discharges; spike detection; epilepsy; unsupervised; Fourier transform; STFT; short-time Fourier transform; CWT; continuous wavelet transform; DWT; discrete wavelet transform; ML; machine learning; ANN; artificial neural network; CNN; convolutional neural network; autoencoder; HMM; hidden Markov model; ECS; Euclidean distance of cumulative spectrum;

    Sammanfattning : Epilepsy affects more than 50 million people and is one of the most prevalent neurological disorders and has a high impact on the quality of life of those suffering from it. However, 70% of epilepsy patients can live seizure free with proper diagnosis and treatment. Patients are evaluated using scalp EEG recordings which is cheap and non-invasive. LÄS MER

  4. 3. Prediktivt underhåll av transformatorstationer genom automatisk analys av störningsdata i COMTRADE-filer

    M1-uppsats, KTH/Hälsoinformatik och logistik

    Författare :Simon Bidros; Ström Gustav; [2023]
    Nyckelord :COMTRADE; predictive maintenance; wavelet transform; substation; relay protection; COMTRADE; prediktivt underhåll; wavelettransform; transformatorstation; reläskydd;

    Sammanfattning : Arbetet beskriver möjligheten att kunna utföra prediktivt underhåll med hjälp av information frånCOMTRADE störningsfiler. En mjukvarualgoritm som hämtar tidsförlopp för händelser som uppstårvid störningar och kan ge indikationer på ifall reläer eller strömbrytare faller utanför optimalaarbetsförhållanden har utvecklats. LÄS MER

  5. 4. Vibroacoustic Analysis of an OLTC Diverter Switch for Condition Monitoring : Time frequency analysis with Fourier and wavelet transform in combination with multivariate logistic regression for condition monitoring of OLTC diverter switch

    Uppsats för yrkesexamina på avancerad nivå, Uppsala universitet/Avdelningen för systemteknik

    Författare :Simon Persson; [2023]
    Nyckelord :Wavelet transform; CWT; logistic regression; machine learning; ML; vibroacoustic analysis; time frequency analysis; tap changer; diverter switch; power transformer; classification; prediction; condition; vibrations; state prediction; Hitachi Energy;

    Sammanfattning : Vibrations are everywhere around us all the time and we often recognise them as sounds that we can hear and analyse with our brain. In this thesis, data that has been gathered from a diverter switch (DS) in a controlled environment, is analysed. LÄS MER

  7. 5. Dealing With Speckle Noise in Deep Neural Network Segmentation of Medical Ultrasound Images

    Master-uppsats, KTH/Skolan för kemi, bioteknologi och hälsa (CBH)

    Författare :Olmo Daniel; [2022]
    Nyckelord :Deep Learning; Ultrasound; Speckle Filtering; Medical Image Segmentation; U-Net; Wavelet Transfrom; Djupinlärning; Ultraljud; Specklefiltrering; Medicinsk bildsegmentering; U-Net; Wavelet transformation;

    Sammanfattning : Segmentation of ultrasonic images is a common task in healthcare that requires time and attention from healthcare professionals. Automation of medical image segmentation using deep learning solutions is fast growing field and has been shown to be capable of near human performance. LÄS MER