Sökning: "Wavelengths"

Visar resultat 1 - 5 av 193 uppsatser innehållade ordet Wavelengths.

  1. 1. Heart rate estimation from wrist-PPG signals in activity by deep learning methods

    Master-uppsats, KTH/Skolan för elektroteknik och datavetenskap (EECS)

    Författare :Marie-Ange Stefanos; [2023]
    Nyckelord :Deep Learning; Medical Data; Signal Processing; Heart Rate Estimation; Wrist Photoplethysmography; Djup lärning; Medicinska Data; Signalbehandling; Pulsuppskattning; Handledsfotopletysmograf;

    Sammanfattning : In the context of health improving, the measurement of vital parameters such as heart rate (HR) can provide solutions for health monitoring, prevention and screening for certain chronic diseases. Among the different technologies for HR measuring, photoplethysmography (PPG) technique embedded in smart watches is the most commonly used in the field of consumer electronics since it is comfortable and does not require any user intervention. LÄS MER

  3. 2. Antenna measurements of HF antennas using low cost UAVs

    Kandidat-uppsats, KTH/Skolan för elektroteknik och datavetenskap (EECS)

    Författare :Ruimin Ma; Jinting Zhang; [2023]
    Nyckelord :Antenna; HF; UAV; Radiation Pattern; Antenna; HF; UAV; Strålningsmönster;

    Sammanfattning : High-frequency signal far-field measurement systems usually involve the use of complex and expensive equipment, since the measurements must be made at a distance of multiple wavelengths from the antenna. Helicopter surveyors are commonly utilized. LÄS MER

  4. 3. Laboratory starlight simulator for future space-based heterodyne interferometry

    Master-uppsats, Luleå tekniska universitet/Rymdteknik

    Författare :William Karlsson; [2023]
    Nyckelord :Angular resolution; Astronomy; Coherence length; Digital delay lines; Fiber optical circuit; Heterodyne interferometry; Interference; Laboratory starlight simulator; NIR light Near-Infrared ; Optical path differences; Space exploration; Starlight; Testbed environment;

    Sammanfattning : In astronomy, interferometry by ground-based telescopes offers the greatest angular resolution. However, the Earth´s atmosphere distorts the incident wavefront from a celestial object, leading to blurring and signal loss. It also restricts the transmission of specific wavelengths within the electromagnetic spectrum. LÄS MER

  5. 4. Generation of attosecond X-ray pulses in free-electron lasers using electron energy modulation and undulator tapering

    Uppsats för yrkesexamina på avancerad nivå, Uppsala universitet/FREIA

    Författare :Karl-Fredrik Boholm Kylesten; [2023]
    Nyckelord :attosecond; free-electron laser; XFEL; self-amplified spontaneous emission; SASE; tapering; energy modulation;

    Sammanfattning : Free-electron lasers (FELs) are among the world's most intense artificial artificial sources of coherent light and are tunable to various wavelengths, including the X-ray spectrum. X-ray FELs (XFELs) are extremely useful for diffraction experiments to study molecules, materials, and quantum systems. LÄS MER

  7. 5. Improving the experimental setup for ultrasound-optical tomography imaging

    Uppsats för yrkesexamina på avancerad nivå, Luleå tekniska universitet/Institutionen för teknikvetenskap och matematik

    Författare :Ibtisam Dahir Ahmed; [2023]
    Nyckelord :Ultrasound-optical tomography UOT ; thulium-doped lithium niobate;

    Sammanfattning : According to Bröstcancer förbundet, mammography is not efficient at detecting tumors in dense breast tissue or diagnosing breast cancer at its early stages. Ultrasound-optical tomography (UOT) is an imaging technique in development and has the potential for deep-tissue imaging. LÄS MER