Nicolas-Alexander Tatlas

Wireless Digital Audio Delivery Analysis and Evaluation

Real-time digital wireless playback of CD-quality audio in multipoint setups using quality of service enhancements is analyzed and evaluated in this work. A novel methodology is introduced for simulating wireless digital audio delivery as well as for theoretically deriving the playback distortions. This methodology allows the accurate wireless digital audio delivery and reproduction simulation and leads to significant results for both the wireless networking and audio playback performance, while it provides a framework for defining the optimal parameters for error-free wireless stereo audio reproduction

Sonic perceptual crossings: a tic-tac-toe audio game

The development of audio-only computer games imposes a number of challenges for the sound designer, as well as for the human machine interface design approach. Modern sonification methods can be used for effective data and game-environment or conditions representation through sound, including earcons and auditory icons. In this work we take advantage of earcons fundamental characteristics, such as spatialization usually employed for concurrent/parallel reproduction, in order to implement a tic-tac-toe audio game prototype. The proposed sonic design is transparently integrated with a novel user control/interaction mechanism that can be easily implemented in state-of-the-art mobile devices incorporating movement sensors (i.e. accelerometers and gyroscope). The overall prototype design efficiency is assessed in terms of the employed sonification accuracy, while the playability achieved through the integration of the sonic design and the employed auditory user interface is assessed in real game-play conditions.

WLAN technologies for audio delivery

Audio delivery and reproduction for home or professional applications may greatly benefit from the adoption of digital wireless local area network (WLAN) technologies. The most challenging aspect of such integration relates the synchronized and robust real-time streaming of multiple audio channels to multipoint receivers, for example, wireless active speakers. Here, it is shown that current WLAN solutions are susceptible to transmission errors. A detailed study of the IEEE802.11e protocol (currently under ratification) is also presented and all relevant distortions are assessed via an analytical and experimental methodology. A novel synchronization scheme is also introduced, allowing optimized playback for multiple receivers. The perceptual audio performance is assessed for both stereo and 5-channel applications based on either PCM or compressed audio signals.

A Wireless Acoustic Sensor Network for environmental monitoring based on flexible hardware nodes

Monitoring areas of environmental interest by employing a wireless acoustic sensor network has been recently investigated. Although feature-rich sensor solutions have surfaced, the requirements for a flexible node from a networking and processing segmentation point of view cannot be met by commercially available systems. The hardware development presented is based on a single design that can support multiple subsystems with the actual node operation being defined by the embedded software. The systems performance was investigated through a six month pilot operation; for that duration, data for anthropogenic, geophysical and biophysical sounds were logged.

Accessible electronic games for blind children and young people.

Abstract: We present a suite of inclusive games designed to address the needs of people with blindness or low vision. Particularly, through the employment of modern sonification strategies that achieves efficient perceptual representation of the game‐play, several audio‐games with different scenarios and application scope (entertainment and education) were developed and demonstrated. A platform called “Memor‐i studio” that allows nontechnical users (including blind ones under supervision) to create such inclusive games has also been developed. The overall presentation includes the detailed description of the outcome of the evaluation process involved children and young people aged between 7 and 20 years old from the Special Elementary School for the Blind in Athens and the Education and Rehabilitation Centre for the Blind in Athens, Greece. The description is also extended to include the design framework of Memor‐i studio. The conclusions of this evaluation are unexpectedly encouraging, showing that the specific type of inclusive games genre may be a strong alternative toward the development of accessible games for blind people, providing a secure starting point for future developments on this field. [ABSTRACT FROM AUTHOR]

PC-based room correction for audio

The characteristics and implementation of a complete software bundle consisting of a room acoustics measurement tool, an application for the calculation of the room correction filters and a plugin for real time audio filtering is described. Via this plug-in a non-experienced user should be able to follow the documentation, measure the impulse response of his listening room, calculate the appropriate stereo inverse filters and utilize them in order to equalize the audio input in real time. The proposed room equalization solution was evaluated in terms of subjective and objective performance.