Searched for: subject%3A%22Doppler%22
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Wansink, Nick (author)
Micromechanical resonators, which have become feasible due to advanced manufacturing techniques, have shown several interesting phenomena including mode coupling in a range of applications that span metrology and sensing. Conventional fabrication methods of these resonators have been used throughout the field. However, fabrication of...
master thesis 2024
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Dash, T.K. (author), Driessen, J.N. (author), Krasnov, O.A. (author), Yarovoy, Alexander (author)
The challenge of reconstructing the Doppler spectrum of a precipitation-like event observed by a fast-scanning weather radar is addressed. A novel method is proposed where the echo sequence in time is assumed to be a complex Gaussian process with a known covariance structure. It is a two-step approach where the first step is the estimation of...
conference paper 2024
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Kortenbout, A.J. (author), Costerus, Sophie (author), Dudink, Jeroen (author), de Jong, N. (author), de Graaff, Jurgen C. (author), Vos, H.J. (author), Bosch, Johan G. (author)
Objective: Post-operative brain injury in neonates may result from disturbed cerebral perfusion, but accurate peri-operative monitoring is lacking. High-frame-rate (HFR) cerebral ultrasound could visualize and quantify flow in all detectable vessels using spectral Doppler; however, automated quantification in small vessels is challenging...
journal article 2024
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Hernandez-Burgos, Sergi (author), Gibert, Ferran (author), Broquetas, Antoni (author), Kleinherenbrink, M. (author), De la Cruz, Adrian Flores (author), Gomez-Olive, Adria (author), Garcia-Mondejar, Albert (author), Aparici, Monica Roca i. (author)
The 2-D frequency-based omega-K method is known to be a suitable algorithm for fully focused SAR (FF-SAR) radar altimeter processors, as its computational efficiency is much higher than equivalent time-based alternatives without much performance degradation. In this article, we provide a closed-form description of a 2-D frequency-domain omega...
journal article 2024
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Chang, X. (author), Wellens, P.R. (author)
The lack of suitable boundary conditions in practical surface wave simulations with maritime structures in current or at forward speed may cause energy in the computational domain to accumulate due to spurious wave reflection. The common way to prevent wave reflection is to use passive wave absorbers, such as damping zones or relaxation zones...
journal article 2024
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Zeng, Y. (author), Nunez, Alfredo (author), Li, Z. (author)
A transfer function (TF) is an effective representation of the load-response relationship of railway track structures. To fill the gap in measuring track structure TFs over a wide frequency range from a moving vehicle, we develop a TF measurement system and the associated TF estimation methodology. Accelerometers are utilized to estimate the...
journal article 2024
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Eenkhoorn, C. (author), Goos, T.G. (author), Dankelman, J. (author), Franx, Arie (author), Eggink, Alex J. (author)
Introduction: In clinical practice, fetal heart rate monitoring is performed intermittently using Doppler ultrasound, typically for 30 minutes. In case of a non-reassuring heart rate pattern, monitoring is usually prolonged. Noninvasive fetal electrocardiography may be more suitable for prolonged monitoring due to improved patient comfort and...
journal article 2024
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Dash, T.K. (author), Driessen, J.N. (author), Krasnov, O.A. (author), Yarovoy, Alexander (author)
The problem of the limited accuracy of precipitation Doppler spectrum moments estimation measured by fast azimuthally scanning weather radars is addressed. A novel approach for the Doppler moment estimation based on maximum likelihood estimation is proposed. A simplified semianalytical parametric model for the precipitation power spectral...
journal article 2024
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Zeng, Y. (author)
doctoral thesis 2023
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Sprenkels, Amber (author)
This thesis analyses the possibility of creating a portable Doppler tracking ground station using commercial of the shelf components. This solution is called DopTrackBox and is based on TU Delft’s DopTrack. This system uses the Doppler shift of radio signals received from satellites to analyse their location and velocity. Different experiments...
master thesis 2023
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Jin, J. (author)
Laser Doppler vibrometer (LDV) is a vibration-detecting instrument for noncontact and non-destructive measurement. It is superior to classic contact transducers in terms of the wide frequency range and high measurement resolution. LDV on moving platforms (LDVom) is one of the LDV measurement technology to one-way scan the vibrating surface, so...
doctoral thesis 2023
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Liu, Tianyi (author)
Transcranial Doppler ultrasound imaging is a crucial tool for both clinical and research applications. Despite its significance, its utility is constrained by the dynamic range limitations of the receiver system. Traditional methods, relying on high-dynamic-range front-end amplifiers and high-resolution ADCs, are often inefficient. These methods...
master thesis 2023
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XIAO, Jiaxuan (author)
Autonomous driving can bring revolutionary advancements in transportation, by making vehicles navigate and operate independently without human intervention. To achieve this, autonomous vehicles are equipped with sensors, including cameras, Light Detection and Ranging (LiDAR), and radar, which provide them with a comprehensive view of their...
master thesis 2023
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Pappas, Apostolos (author)
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master thesis 2023
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ZHU, LEXI (author)
Doppler ultrasound imaging of cerebral blood flow faces challenges arising from a low signal-to-noise ratio (SNR) and a wide dynamic range. Echo signals received from blood cells are significantly weaker compared to surrounding tissues, such as the skull or brain soft tissue, resulting in inhibited visualization of small blood vessels and deep...
master thesis 2023
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Gao, Xuan (author)
Micro-Doppler (µDoppler) ultrasound imaging is a high frame rate ultrasound imaging modality that provides high spatiotemporal resolution ultrasound images of blood flow. It is sensitive to slow blood flow and particularly suitable for capturing fast-changing phenomena like rapid blood flow. Clutter filtering is an essential step in µDoppler...
master thesis 2023
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van Nifterik, Bob (author)
Radar micro-Doppler signatures are powerful indicators of target movements and activities, enabling the extraction of valuable information about various objects' internal and external dynamics. Consequently, classifying these signatures has become crucial in numerous applications, ranging from target recognition in surveillance, to biomedical...
master thesis 2023
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Focante, Edoardo (author)
In recent years, neural networks (NNs) have seen a surge in popularity due to their ability to model complex patterns and relationships in data. One of the challenges of using NNs is the requirement for large amounts of labelled data to train the model effectively. In many real-world applications such as radar, labelled data may be scarce due to...
master thesis 2023
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Generowicz, Bastian S. (author), Dijkhuizen, Stephanie (author), Bosman, Laurens W.J. (author), De Zeeuw, Chris I. (author), Koekkoek, Sebastiaan K.E. (author), Kruizinga, P. (author)
Functional ultrasound (fUS) using a 1-D-array transducer normally is insufficient to capture volumetric functional activity due to being restricted to imaging a single brain slice at a time. Typically, for volumetric fUS, functional recordings are repeated many times as the transducer is moved to a new location after each recording, resulting...
journal article 2023
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Generowicz, Bastian S. (author), Dijkhuizen, Stephanie (author), De Zeeuw, Chris I. (author), Koekkoek, Sebastiaan K.E. (author), Kruizinga, P. (author)
Volumetric 3-D Doppler ultrasound imaging can be used to investigate large scale blood dynamics outside of the limited view that conventional 2-D power Doppler images (PDIs) provide. To create 3-D PDIs, 2-D-matrix array transducers can be used to insonify a large volume for every transmission; however, these matrices suffer from low...
journal article 2023
Searched for: subject%3A%22Doppler%22
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