Sökning: "Frequency methods"

Visar resultat 1 - 5 av 1576 avhandlingar innehållade orden Frequency methods.

  1. 1. Active Control of Propeller-Induced Noise in Aircraft : Algorithms & Methods

    Författare :Sven Johansson; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; active control of sound; active noise control; anc; actuator individual normalized filtered-x lms; filtered-x lms algorithm; newton algorithm; complex lms; multireference algorithm; leaky lms; control effort weighting; feedforward control; feedback contro;

    Sammanfattning : In the last decade acoustic noise has become more and more regarded as a problem. In cars, boats, trains and aircraft, low-frequency noise reduces comfort. Lightweight materials and more powerful engines are used in high-speed vehicles, resulting in a general increase in interior noise levels. LÄS MER

  3. 2. Pitch, loudness and frequency selectivity in low-frequency hearing loss

    Författare :Jonas Brännström; Lund näs- och halssjukdomar Öron-; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; frequency coding; Cochlea; frequency selectivity; hearing fluctuation; inner ear pressure; long-term measurement; Ménière s disease; low-frequency hearing loss; loudness; pitch.;

    Sammanfattning : Patients with Ménière's disease and cochlear hydrops show fluctuating low-frequency hearing loss (FLFHL). At present these changes are followed as patients' subjective reports and occasional measurements. LÄS MER

  4. 3. Methods in time-frequency analysis

    Författare :Johan Brynolfsson; Statistical Signal Processing Group; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : .... LÄS MER

  5. 4. Low frequency noise during work. Effects on performance and annoyance

    Författare :Johanna Bengtsson; Göteborgs universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Low frequency noise; performance; workload; annoyance; cortisol; subjective stress; subjective sensitivity to noise; sound characteristics; frequency balance; modulation frequency;

    Sammanfattning : Aims. Low frequency noise (LFN) is defined as "a noise with a dominant frequency content of 20 to 200 Hz". Common sources of LFN in occupational environments are ventilation, heating and air-conditioning systems, computer network installations and compressors. LÄS MER

  7. 5. Numerical Methods for Turbomachinery Aeromechanical Predictions

    Författare :Maria Angelica Mayorca; Damian Vogt; Torsten Fransson; Robert Kielb; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aeromechanics; numerical tools; methods; turbomachinery; aeroelasticity; gas turbines; vibrations;

    Sammanfattning : In both aviation and power generation, gas turbines are used as key components. An important driver of technological advance in gas turbines is the race towards environmentally friendly machines, decreasing the fuel burn, community noise and NOx emissions. LÄS MER