03. Lisensiaatin tutkinnon opinnäytteet / Licentiate theses

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Browsing 03. Lisensiaatin tutkinnon opinnäytteet / Licentiate theses by Degree programme/Major subject "Acoustics and Audio Signal Processing"

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    An agent-based method for self-study interactive web-based education
    (Teknillinen korkeakoulu, 2006) Rahkila, Martti; Karjalainen, Matti; Prof.; Department of Electrical and Communications Engineering; Sähkö- ja tietoliikennetekniikan osasto; Karjalainen, Matti; Prof.
    This thesis deals with computer-based education of acoustics and digital signal processing. The focus throughout the thesis is on interactive, self-study web-based applications even though many issues are of more general nature as well. The emphasis is especially on describing interactivity while using educational applications and the use of log information for evaluation of learning. The goal for the thesis has been to develop a web-based solution for audio signal processing education with emphasis on advanced, intelligent interactivity. The basis for this interactivity is the double agent architecture for web applications. The architecture allows the control of the interaction process by means of logs and using them as a basis for content adaptation. Furthermore, the novelty of this method is its applicability to evaluation of learning. The log information, provided by the architecture, can be used for on-line evaluation of users' requests and thus provides means for content adaptation. Furthermore, the log information can also be post-processed and used for off-line evaluation of the learning process by both teachers as well as students themselves. The latter has also pedagogical importance supporting the development of self-reflection and metacognitive skills.
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    Methods of automatic audio content classification
    (Teknillinen korkeakoulu, 2007) Pohjalainen, Jouni; Kurimo, Mikko;; Department of Electrical and Communications Engineering; Sähkö- ja tietoliikennetekniikan osasto; Laine, Unto K.; Prof.
    This study presents an overview of different methods of digital signal processing and pattern recognition that are frequently applicable to automatic recognition, classification and description of audio content. Moreover, strategies for the combination of the said methods are discussed. Some of the published practical applications from different areas are cited to illustrate the use of the basic methods and the combined recognition strategies. A brief overview of human auditory perception is also given, with emphasis on the aspects that are important for audio recognition.
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    Parametric Spatial Audio in Hearing Performance Evaluation of Hearing-Impaired and Aided Listeners
    (Aalto University, 2018) Koski, Teemu; Pulkki, Ville, Assoc. Prof., Aalto University, Department of Signal Processing and Acoustics, Finland; Signaalinkäsittelyn ja akustiikan laitos; Department of Signal Processing and Acoustics; Sähkötekniikan korkeakoulu; School of Electrical Engineering; Pulkki, Ville, Assoc. Prof., Aalto University, Department of Signal Processing and Acoustics, Finland
    Clinical hearing performance testing has conventionally been conducted by measuring the detection thresholds for narrow-band stimuli or the reception of speech in quiet. However, especially hearing-impaired individuals and hearing device users generally have the most problems in communication situations involving dynamic background noise or reverberation, and these problems are not necessarily reflected well with these measures. Thus, methods have been developed to more accurately assess the real-life representative hearing performance using multiple loudspeakers. However, many of the current systems are either too large and complex for clinical environments or do not reproduce the spatial characteristics of the sound scene correctly. Directional Audio Coding (DirAC) is a parametric perceptually-motivated spatial sound reproduction technique. With DirAC, the spatial attributes of sound can be captured and reproduced with arbitrary loudspeaker setups. In this thesis, DirAC was applied to reproducing sound scenes and reverberation for realistic hearing performance testing. A method is proposed for conducting speech intelligibility assessments in realistic pre-recorded sound scenes where an external speech target is augmented. With listening tests, a comparison was made between a reference sound scene and a reproduced scene where the reference was reproduced by the method under investigation. Furthermore, analysis of the error sources was provided when the system is used in aided listening, where the test subject listens the reproduced sound scene through a hearing device beamformer. Requirements were specified for a clinical implementation of the system. The main advantage of the system is that with certain limitations it enables a fairly accurate assessments of real-life hearing abilities using a relatively compact loudspeaker setup.