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Adaptive Approach to Acoustic Car Driving Detection in Mobile Devices

100%
Aksamit P.
Acta Physica Polonica A
|
2013
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vol. 124
|
issue 3
381-383
EN
The context awareness of mobile devices is broadly researched area as it improves the functionality, usability, safety of usage and intelligence of the device as perceived by its user. The special type of context is driving a car. The awareness of a mobile device whose user drives a car may allow to disable some features like making and taking phone calls and enable other features like e.g. navigation thus improving the safety of the user. The paper presents the results of a research on acoustic detection of car driving based on over 60 h of collected data. The modification of traditional k-nearest neighbors classification algorithm is proposed that allows for learning and adaptation of classifier configuration. The proposed approach significantly improves both the sensitivity and specificity of the classifier comparing to the classifier based only on offline training data. The challenges in performing the acoustic wave analysis using highly heterogeneous devices like mobile phones are discussed.
2
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Analysis and Elaboration of an Air-Coupled Ultrasound Wideband Sensor Array

100%
Herman K., Stach L.
Acta Physica Polonica A
|
2013
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vol. 123
|
issue 1
31-33
EN
In this paper a design process of 64 sensor matrix is described. This study presents adaptation of well known sonar engineering methods of analysis in order to design air operating ultrasound beamforming system. The elaborated system is based on wideband micro electro-mechanical systems. A full digital beamformer with advanced digital signal processing block description is also included. The main goal of the system is direct of arrival of ultrasound wave estimation.
3
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Evaluation of the Active Plate Vibration Reduction by the Parameter of the Acoustic Field

100%
Brański A., Szela S.
Acta Physica Polonica A
|
2011
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vol. 119
|
issue 6A
942-945
EN
Effectiveness of the active vibration reduction of triangular plate is evaluated by way of the analysis of acoustical field. The active vibration reduction is performed with actuators. The effect is measured by the analysis of the acoustical field both far distance and near one from the plate. As the control parameter, the difference between acoustical pressures is considered. The first pressure and the second one are radiated by the plate without and with the vibration reduction, respectively. The control parameter is calculated for two reduction cases. First case, when actuators are attached at so-called quasi-optimal places and second one, when they are shifted. The numerical calculations show that the acoustical field is sensitive to change of the plate active vibration reduction. It responds to even little changes of the plate vibrations in both active reduction cases mentioned above. So that it is handy indirect control parameter of the active vibration reduction.
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