@conference{kowalk2018,
 author = {Kowalk, U. and Holube, I. and Franz, S. and Groenewold, H. and Gablenz, P. v. and Kissner, S. and Bitzer, J.},
 title = {An open source toolkit for privacy-preserving real-world EMA data collection},
 abstract = {Modern audiological studies show a deep interest in the combination of objective data and subjective ratings, especially when personal benefit of rehabilitation measures is the desired entity. In order to perform experiments that gather data of both varieties in an ecological, compliant, and privacy-preserving manner, we developed and evaluated a system modeled around a smartphone allowing for comfortable usage with minimal user interaction needed. Audio signals recorded close to the ears are transmitted to the device via a stereo A2DP bluetooth stream. All objective parameters are then extracted in real time and no audio data is stored. Simultaneous to recording objective data, surveys are taken in situ on the smartphone at a fixed or random time interval. Questionnaire design follows a simple set of rules and new surveys can be produced without any programming skills. This system is the central element of data collection within the IHAB-RL study on hearing aid benefit in real-world scenarios. The technical assessment of the system has shown a flat frequency response with low inherent noise, a sufficient dynamic range, and a runtime suitable for real-life experiment purposes. The interface itself has been designed for unambiguity and clean display of only the most essential variables. While the software may traverse different states and handle various tasks in the background, the user is only involved in case of critical battery level or permanent loss of the downlink. With our new evaluation software we are able to display compressed results of whole multi-day experiments (compare the corresponding IHCON contribution Gablenz et al, 2018). An external module checks all data blocks for plausibility, ensuring that only meaningful data is included. In order to manage the huge amount of data and enable international collaboration, we designed and implemented a database, which is specifically structured for ease of access, expandability, and assignment of individual permissions. Access and permission management is facilitated by a specially tailored programming interface (API). Furthermore, a revised hardware design is presented which utilizes a serial wireless connection to the benefit of increased dynamic range, broader control of the system variables and a less restricted catalog of usable hardware. In order to promote collaborative approaches, all software is published under an open source license while all hardware plans are made available under an open hardware license.},
 keywords = {EMA, android, smartphone, IHAB},
 tags = {EMA, IHAB-RL, Acoustical Measurements, Fragebogen, H+A, HALLO, Höranstrengung, Hörgeräte, Sprachverstehen},
 booktitle = {International Hearing Aid Research Conference (IHCON), Lake Tahoe, CA, USA},
 year = {2018},
}