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AES Munich 2009
Poster Session P15

Friday, May 8, 16:30 — 18:00

P15 - Hearing

P15-1 Psychoacoustics and Noise Perception Survey in Workers of the Construction SectorMarcos D. Fernández; Bálder Vitón; José Antonio Ballesteros, Samuel Quintana, Isabel González, Escuela Universitaria Politécnica de Cuenca, Universidad de Castilla-La Mancha - Cuenca, Spain
Noise levels are not enough to assess completely the influence of the noise. Therefore, psychoacoustics and perception surveys should be taken into account. The noise that the construction workers produce in their tasks is recorded with a HATS. Later, those recordings are processed to derive different parameters: spectrum, weighted equivalent levels, and the main psychoacoustics parameters. After that, a specific survey has been developed to assess the perception of such activity noises during the working time to correlate adjectives of perception with those parameters mentioned. The survey has been designed to be answered by the workers that are exposed to the noise, so that conclusions could be derived about the feelings and annoyance that the noise can cause.
Convention Paper 7734 (Purchase now)

P15-2 On the Design of Automatic Sound Classification Systems for Digital Hearing AidsEnrique Alexandre, Lorena Álvarez-Perez, Roberto Gil-Pita, Raúl Vicen-Bueno, Lucas Cuadra, University of Alcalá - Alcalá de Henares, Spain
The design of digital hearing aids able to carry out advanced functionalities (such as, for instance, classify the acoustic environment and automatically select the best amplification program for the user’s comfort) exhibits a great difficulty. Since hearing aids have to work at very low clock frequency in order to minimize power consumption and maximize life battery, the number of available instructions per second is actually very small. This enforces the design of efficient algorithms with a reduced number of instructions. In particular, this paper will focus on three extremely related topics: (1) the design of low-complexity features; (2) the use of automatic feature selection algorithms to optimize the performance of the classifier; and (3) the critical analysis of a variety of different classification algorithms, basically based on their complexity and performance and determining whether or not they are feasible to be implemented.
Convention Paper 7735 (Purchase now)

P15-3 Pruning Algorithms for Multilayer Perceptrons Tailored for Speech/Non-Speech Classification in Digital Hearing AidsLorena Álvarez, Enrique Alexandre, Manuel Rosa-Zurera, University of Alcalá - Alcalá de Henares, Spain
This paper explores the feasibility of using different pruning algorithms for multilayer perceptrons (MLPs) applied to the problem of speech/non-speech classification in digital hearing aids. A classifier based on MLPs is considered the best option in spite of its presumably high computational cost. Nevertheless, its implementation has been proven to be feasible: it requires some trade-offs involving a balance between reducing the computational demands (that is, the number of neurons) and the quality perceived by the user. In this respect, this paper will focus on the design of three novel pruning algorithms for MLPs, which attempt to converge to the minimum complexity network (that is, the lowest number of neurons in the hidden layer) without degrading the performance of it. The results obtained with the proposed algorithms will be compared with those obtained when using another pruning algorithm proposed in the literature.
Convention Paper 7736 (Purchase now)

P15-4 Evolutionary Optimization for Hearing Aids of Computational Auditory Scene AnalysisAnton Schlesinger, Marinus M. Boone, Technical University of Delft - Delft, The Netherlands
Computational auditory scene analysis (CASA) provides an excellent means to improve speech intelligibility in adverse acoustical situations. In order to utilize algorithms of CASA in hearing aids, sets of algorithmic parameters need to be adjusted to the individual auditory performance of the listener and the acoustic scene in which they are employed. Performed manually, the optimization is an expensive procedure. We therefore developed a framework in which algorithms of CASA are automatically optimized by the principles of evolution, i.e., by a genetic algorithm. By using the speech transmission index (STI) as an objective function, the presented framework presents a holistic routine that is solely based on psychoacoustical and physiological models to improve and to assess speech intelligibility. The initial listening test revealed a discrepancy between the objective and subjective assessment of speech intelligibility, which suggests a review of the objective function. Once the objective function is in accordance with the individual perception of speech intelligibility, the presented framework could be applied in the optimization of all complex speech processors and therewith accelerate their assessment and application.
Convention Paper 7737 (Purchase now)

P15-5 Enhanced Control of On-Screen Faders with a Computer MouseMichael Hlatky, Kristian Gohlke, David Black, Hochschule Bremen (University of Applied Sciences) - Bremen, Germany; Jörn Loviscach, Fachhochschule Bielefeld (University of Applied Sciences) - Bielefeld, Germany
Input devices of the audio studio that formerly were physical have mostly been converted into virtual controls on the computer screen. Whereas this transition saves space and cost, it has reduced the performance of these controls, as virtual controls adjusted using the computer mouse do not exhibit the accuracy and accessibility of their physical counterparts. Previous studies show that interaction with scrollable timelines can be enhanced by an intelligent interpretation of the mouse movement. We apply similar techniques to virtual faders as used for audio control, leveraging such approaches as controllable zoom levels and pseudo-haptic interaction. Tests conducted on five such methods provide insight into how to decouple the fader from the mouse movement to improve accuracy without impairing the speed of the interaction.
Convention Paper 7738 (Purchase now)

P15-6 Modeling of External Ear Acoustics for Insert Headphone UsageMarko Hiipakka, Miikka Tikander, Matti Karjalainen, Helsinki University of Technology - Espoo, Finland
Although acoustics of the external ear has been studied extensively for auralization and hearing aids, the acoustic behavior with insert headphones is not as well known. Our research focused on the effects of outer ear physical dimensions, particularly on sound pressure at the eardrum. The main parameter was the length of the canal, but eardrum’s damping of resonances was also studied. Ear canal simulators and a dummy head were constructed. Measurements were also performed from human ear canals. The study was carried out both with unblocked ear canals and when the canal entrance was blocked with an insert earphone. Special insert earphones with in-ear microphones were constructed for this purpose. Physics-based computational models were finally used to validate the approach.
Convention Paper 7739 (Purchase now)