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Huijbrechts, Maartje (author)Macro X-ray fluorescence (MA-XRF) is a recently developed technology allowing to obtain elemental information from cultural heritage objects. This information can, for example, be used to identify pigments used in a painting. Yet, the extended period of time it takes to scan an object is a major issue within MA-XRf. For instance, it took about...master thesis 2023
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Joyandeh, Arian (author)With the rise of zero-shot synthetic image generation models, such as Stability.ai's Stable Diffusion, OpenAI's DALLE or Google's Imagen, the need for powerful tools to detect synthetic generated images has never been higher. In this thesis we contribute to this goal by considering wavelet-based approaches for synthetic image detection.<br/><br/...master thesis 2023
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Licurici, Teodor (author)Estimating the transmembrane currents travelling through the epicardium and local activation times based on atrial epicardial electrograms can greatly help in the study of cardiac arrhythmias such as atrial fibrillation. This work focuses on the accurate estimation of the aforementioned signals and features. To do this, two least squares-based...master thesis 2023
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Koppensteiner, Sarah (author), van Velthoven, J.T. (author), Voigtlaender, Felix (author)This paper provides maximal function characterizations of anisotropic Triebel–Lizorkin spaces associated to general expansive matrices for the full range of parameters p∈ (0 , ∞) , q∈ (0 , ∞] and α∈ R. The equivalent norm is defined in terms of the decay of wavelet coefficients, quantified by a Peetre-type space over a one-parameter dilation...journal article 2023
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Meloni, S. (author), de Paola, E. (author), Grande, E. (author), Ragni, D. (author), Stoica, L. G. (author), Di Marco, A. (author), Camussi, R. (author)Propeller noise generally exhibits a rich mixture of tonal and broadband components related to different physical mechanisms. Specifically, the tones are characterized by having deterministic and persistent characteristics, while the broadband counterpart has random behaviour. The separation is essential for the experimenters as they provide...journal article 2023
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Dirkx, Nic (author), Tiels, Koen (author), Oomen, T.A.E. (author)Frequency response function (FRF) estimation from measured data is an essential step in the design, control, and analysis of complex dynamical systems, including thermal and motion systems. Especially for systems that require long measurement time, missing samples in the data record, e.g., due to measurement interruptions, often occur. The...journal article 2023
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Kekkonen, H.N. (author), Lassas, Matti (author), Saksman, Eero (author), Siltanen, Samuli (author)We propose alternatives to Bayesian prior distributions that are frequently used in the study of inverse problems. Our aim is to construct priors that have similar good edge-preserving properties as total variation or Mumford-Shah priors but correspond to well-defined infinite-dimensional random variables, and can be approximated by finite...journal article 2023
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Dependence and risk spillovers among clean cryptocurrencies prices and media environmental attentionNdubuisi, G.O. (author), Urom, Christian (author)This paper examines the relationships among cryptocurrency environmental attention and clean cryptocurrencies prices using Time-Varying Parameter Vector Auto-Regression (TVP-VAR) and wavelets techniques. Results show strong connectedness among these variables, implying that the prices of clean cryptocurrencies are influenced by attention on...journal article 2023
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Dimitriou, Dimitris (author), Nastos Konstantopoulos, C. (author), Saravanos, Dimitris (author)A multiresolution finite wavelet domain method, that utilizes Daubechies wavelet and scaling functions for the hierarchical approximation of state variables, is presented. The multiresolution approximation yields a hierarchical set of equations of motion involving the coarse component of generalized displacements, while additional equations...conference paper 2023
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Koppensteiner, Sarah (author), van Velthoven, J.T. (author), Voigtlaender, Felix (author)Continuing previous work, this paper provides maximal characterizations of anisotropic Triebel-Lizorkin spaces F˙p,qα for the endpoint case of p= ∞ and the full scale of parameters α∈ R and q∈ (0 , ∞]. In particular, a Peetre-type characterization of the anisotropic Besov space B˙∞,∞α=F˙∞,∞α is obtained. As a consequence, it is shown that...journal article 2023
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Biagini, D. (author), Pascoe, J.A. (author), Alderliesten, R.C. (author)Although several studies have been performed, the compression after impact (CAI) failure of CFRP is still not entirely understood. It is still unclear what sequence of events determines the onset of failure in CAI tests and how the different damage modes are involved in this process. To experimentally investigate this matter, the present work...journal article 2023
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Liu, L. (author), Lekić, A. (author), Popov, M. (author)The DC transmission line protection technology is crucial for the development of multi-terminal Voltage Source Converter (VSC)-based HVDC systems. This article proposes a robust non-unit traveling wave protection (TWP), which deals with the DC fault area identification and fault type discrimination for high impedance fault...journal article 2023
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Wong, Jing Jing (author)This research consists of two applications of image processing, namely, image compression and image denoising. Image compression aims to reduce the size of an image without losing too many features. This is often used to store a large number of images such as fingerprints. Denoising is a technique for removing noise from an image while...bachelor thesis 2022
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van Denderen, R. Pepijn (author), Kater, Emiel (author), Jans, Luc H. (author), Schielen, R.M.J. (author)The river bed level in low-land rivers like the Rhine branches in The Netherlands changes continuously on various spatial and temporal scales. Large-scale degradation occurs in many rivers due to river-wide engineering interventions, such as channelization, in the last decades and centuries. Local river interventions, such as the construction...journal article 2022
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Candeloro, Paolo (author), Martellini, Edoardo (author), Nederlof, R. (author), Sinnige, T. (author), Pagliaroli, Tiziano (author)The aim of the present manuscript is to investigate the noise footprint of an isolated propeller in different flight configurations for the propulsion of a hybrid-electric aircraft. Experimental tests were performed at the Low-Turbulence Tunnel located at Delft University of Technology with a powered propeller model and flush-mounted...journal article 2022
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Payo-Payo, Marta (author), Bricheno, Lucy M. (author), Dijkstra, Y.M. (author), Cheng, Weicong (author), Gong, Wenping (author), Amoudry, Laurent O. (author)Salt intrusion in surface waters endangers freshwater availability, influences water quality, and affects estuarine ecosystem services with high economic and social values. Salt transport and the resulting salinity distributions result from the non-linear interactions between salt and water dynamics. Estuaries are often considered under ...journal article 2022
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Thangavel, Prasanth (author), Thomas, John (author), Sinha, Nishant (author), Peh, Wei Yan (author), Yuvaraj, Rajamanickam (author), Cash, Sydney S. (author), Chaudhari, Rima (author), Karia, Sagar (author), Dauwels, J.H.G. (author)Objective. Clinical diagnosis of epilepsy relies partially on identifying interictal epileptiform discharges (IEDs) in scalp electroencephalograms (EEGs). This process is expert-biased, tedious, and can delay the diagnosis procedure. Beyond automatically detecting IEDs, there are far fewer studies on automated methods to differentiate epileptic...journal article 2022
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Boskos, D. (author), Cortes, Jorge (author), Martinez Sandez, S. (author)This paper introduces a spectral parameterization of ambiguity sets to hedge against distributional uncertainty in stochastic optimization problems. We build an ambiguity set of probability densities around a histogram estimator, which is constructed by independent samples from the unknown distribution. The densities in the ambiguity set are...conference paper 2022
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Medeiros, R.P. (author), Costa, F.B. (author), Silva, K.M. (author), de Jesus Chavez, Jose (author), Popov, M. (author), Lima Junior, J.R. (author)Phasor-based differential protection is widely used as the main protection function of the power transformer due to its reliability and ability to discriminate internal from external faults and inrush currents. However, these methods present some delays due to phasor convergence during the fault occurrence and can fail during challenging...journal article 2022
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Ranganathan, Archana (author)Electrical faults in the distribution system can lead to interruptions in customer power supply resulting in penalties that are borne by the distribution system operator. Accurate fault classification is an important step in locating the fault to achieve faster network restoration times. This reduces the operational costs of the system operator...master thesis 2021