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When auralizing moving sound sources in Virtual Reality (VR) environments, the two main input parameters are the location and radiated signal of the source. An array measurement-based model is developed to characterize moving sound sources regarding the two parameters in this thesis. This model utilizes beamforming, i.e. delay and sum beamforming (DSB) and compressive beamforming (CB) to obtain the locations and signals of moving sound sources. A spiral and a pseudorandom microphone array are designed for DSB and CB, respectively, to yield good localization ability and meet the requirement of CB. The de-Dopplerization technique is incorporated in the time-domain DSB to address moving source problems. Time-domain transfer functions (TDTFs) are calculated in terms of the spatial locations within the steering window of the moving source. TDTFs then form the sensing matrix of CB, thus allowing CB to solve moving source problem. DSB and CB are further extended to localize moving sound sources, and the reconstructed signals from the beamforming outputs are investigated to obtain the source signals. Moreover, localization and signal reconstruction are evaluated through varying parameters in the beamforming procedures, i.e. steering position, steering window length and source speed for a moving periodic signal using DSB, and regularization parameter, signal to noise ratio (SNR), steering window length, source speed, array to source motion trajectory and mismatch for a moving engine signal using CB. The parameter studies show guidelines of parameter selection based on the given situations in this thesis for modeling moving source using beamforming. Both algorithms are able to reconstruct the moving signals in the given scenarios. Although CB outperforms DSB in terms of signal reconstruction under particular conditions, the localization abilities of the two algorithms are quite similar. The practicability of the model has been applied on pass-by measurements of a moving loudspeaker using the designed arrays, and the results can match the conclusions drawn above from simulations. Finally, a framework on how to apply the model for moving source auralization is proposed.

Engineering. --- Construction --- Industrial arts --- Technology --- Source modeling --- Moving sound sources --- Array measurements --- Auralization --- Beamforming

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While binaural technology applications gained in popularity in recent years, the majority of applications still use non-individual Head-Related Transfer Functions (HRTFs) from artificial heads. However, certain applications, for example research of spatial hearing or hearing attention, require an physically exact and realistic binaural signal. The limiting factor that prohibits the widespread use of individual HRTFs is the acquisition time of such data. This time requirement has recently been reduced by the use of parallelization in the measurement signal which lead to the development of fast measurement systems capable of acquiring individual and spatially dense HRTF. This thesis provides a objective and subjective evaluation of such a system that is designed with the goal of little disturbance of the measurements in mind. The construction is detailed, followed by both an objective and subjective evaluation. A detailed investigation into additional distortion of the sound field introduced by the system itself is presented and it is shown that the system performs comparably to a conventional system in terms of sound source localization. Furthermore, a method is introduced and evaluated to further reduce the measurement time by using continuous rotation during the measurement. This method is used to reduced the measurement duration from eight minutes to three minutes without audible differences.

Technology. --- Applied science --- Arts, Useful --- Science, Applied --- Useful arts --- Science --- Industrial arts --- Material culture --- Akustik --- HRTF --- Messtechnik --- Binauraltechnik --- Psychoakustik

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In einem Solarturmkraftwerk werden hunderte bis tausende Spiegel (sogenannte Heliostate) einzeln der Sonne nachgeführt, sodass das Sonnenlicht auf die Spitze eines Turmes konzentriert wird. Dort befindet sich der Receiver, der die Solarstrahlung absorbiert und an das Wärmeträgermedium weitergibt. Große thermische Energiespeicher erlauben die ganztägige Stromproduktion (auch Nachts). In aktuellen Solarturmkraftwerken kommen als Wärmeträger- und Speichermedium häufig flüssige Nitratsalze wie Solar Salt zum Einsatz. Aufgrund ihrer hohen Wärmekapazität und den geringen Kosten eignen sie sich sehr gut zur thermischen Energiespeicherung, jedoch bringen sie auch einige Nachteile mit sich. Flüssigmetalle weisen in vielen Punkten Vorteile gegenüber den Flüssigsalzen auf. In der vorliegenden Arbeit werden die Eigenschaften von Flüssigmetallen detailliert analysiert und mit Solar Salt verglichen. Zur Bewertung werden die Jahreserträge bzw. die Stromgestehungskosten (LCOE) herangezogen. Die Ergebnisse zeigen ein Potenzial zur Reduktion der Stromgestehungskosten mit Flüssigmetallen um bis zu 16 % gegenüber dem Referenzsystem mit Solar Salt, ohne dabei den Kraftwerksblock und den thermischen Speicher zu verändern.

Technology. --- Solarturmkraftwerk --- Flüssigmetalle --- Flüssigsalz --- Wärmeübertragung --- Concentrated solar power

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Listeners with hearing impairments have difficulties understanding speech in the presence of background noise. Although prosthetic devices such as hearing aids and cochlear implants may improve the hearing capability, listeners with hearing impairments still complain about their speech perception in the presence of noise. The basic tonal audiometry only gives a cursory idea of the degree of difficulty in spoken communication caused by hearing loss because it does not assess the ability to understand speech. Therefore, the use of speech-in-noise tests to measure hearing loss in complex scenes is an integral part of a patient's audiological study. Most research has concentrated on studying only stationary sound sources, but in natural acoustic scenes, conversations may become very difficult to understand in the presence of moving sound sources such as a moving talker or a passing vehicle. Therefore, this thesis deals with quantifying speech perception in the presence of moving maskers through virtual sound sources presented binaurally via headphones. Significant differences in several conditions were found, revealing that the auditory system assesses differently the moving maskers than the stationary maskers. Therefore, the inclusion of moving conditions in clinical listening tests is recommended, in order to assess speech-in-noise perception in a more realistic environment.

Engineering --- Acoustics. --- speech-in-noise perception --- binaural technology --- room acoustics --- moving sound sources --- head movements