Jan-Niklas Antons

Too tired for calling? A physiological measure of fatigue caused by bandwidth limitations

Common methods to determine the quality of media rely on conscious ratings of a subjects opinion about the quality of presented stimuli. While such methods provide a reliable and valid means of determining quality, they provide little insight into the physiological processes preceding the quality judgment, which, however, may affect the subjective behavior, e.g., in terms of alertness or media usage duration. In this paper we used a non-intrusive physiological method, electroencephalography, to assess the cognitive state of subjects related to the quality of auditory speech stimuli. We show that users listening to degraded audio rated the quality lower in comparison to an undisturbed stimulus as expected and, in addition, got more fatigued during the 20 minute presentation. Indicators of the increased fatigue were Theta and Alpha frequencies of the electroencephalogram data. The results show that the perception of degraded media has long-term influences on physiological processes at the time scale of minutes which may immediately influence customer behavior.

Using electroencephalography and subjective self-assessment to measure the influence of quality variations in cloud gaming

Subjective self-assessment is a frequently used method when it comes to Quality of Experience assessment in general. If correctly used a variety of scales can be applied to assess the quality of cloud gaming for different constructs such as experienced quality or flow. Besides self-assessment, physiological correlates are a promising method to measure the influence of cloud gaming quality on the player without the interruption introduced by the rating task. We present subjective and physiological results and lessons learned from a laboratory study in which 32 participants played a first person shooter game in a cloud gaming setup with varying levels of video quality caused by different video compression bitrates. We found that the video quality influenced the perceived quality, player experience, the valence rating, and the alpha frequency band power. It is shown that 1) subjective methods assess the quality variation and 2) physiological measures capture the influence on the player in terms of a reduced cognitive state. Taken together, test set-ups will benefit from a mixed methods approach in cloud gaming QoE testing.

Impact of perceived quality and other influencing factors on emotional video experience

How quality, quality perception and emotions are related, and what this may imply for research on Q, is a question that to date still lacks an unambiguous answer. The study of this relationship is challenging and requires validated emotional stimuli as well as suitable methods and tools to evaluate their emotional impact. This paper shares findings from an inter-laboratory study (N=39), in which electroencephalography data and self-report data on experienced affect, content likeability and perceived quality were collected to evaluate the emotional impact of stimuli from a publicly available database aimed at evoking certain emotional responses. The results call for caution when evaluating emotional impact of such stimuli, as both the self-reported and EEG data point to a number of influencing factors that interfere with the emotion elicitation and need to be taken into account in future research.

A method for feedback delay measurement using a low-cost Arduino microcontroller: Lesson learned: Delay influenced by video bitrate and game-level

Studying cloud gaming QoE, we found the video compression bitrate and the played game level to significantly influence the systems feedback delay. We present a novel low-cost approach to accurately measure the latency between a user command and the system response using the popular Arduino microcontroller platform and conclude with lessons learned for future cloud gaming lab studies.

EEG Frequency Band Power Changes Evoked by Listening to Audiobooks at Different Quality Levels

In the current chapter (Chap. 5, Audiobook Experiment—Constant Quality), the frequency band power of the alpha and theta EEG bands will be analyzed. As stimulus material, speech files with the length of audiobooks will be used. The degradation factors will be differing bit rate conditions of a speech codec with a constant quality level during each presentation block.

ERPs and Quality Ratings Evoked by Word Stimuli and Varying Bit Rate Conditions

The second combined experiment (Word Experiment) described in this chapter will investigate whether the combined EEG/opinion test set-up also functions with word-long stimuli and differing bit rate conditions of a speech codec as degradation factors. This is the third major contribution of this book, showing that the test set-up developed in this context can be applied to longer stimuli and other degradation classes.

General Discussion and Future Work

The general discussion will be structured similar to this book and the presented contributions are as follows: Implementation of a test set-up combining neurophysiological and subjective quality assessment methods for speech quality perception testing. The proof that this test set-up functions with short speech stimuli (phonemes) and a generic quality impairment, i.e. signal-correlated noise. A successful transfer of this test method to longer speech stimuli (words) with a more realistic quality impairment, i.e. reduced bit rate of a speech codec. The proof that this technique works with stimuli of standard length for speech quality assessment (sentences) and an environmental-dependent quality impairment, i.e. reverberation. Investigation of the impact of a speech compression algorithm with reduced bit rate on the cognitive state of listeners for speech stimuli of long duration (audiobooks) in constant and varying quality conditions.

ERPs and Quality Ratings Evoked by Phoneme Stimuli Under Varying SNR Conditions

In this chapter, the first and second contributions of this book will be introduced. First, a test set-up combining neurophysiological and subjective quality assessment methods for speech quality perception testing will be presented. Secondly, the functionality of this set-up will be validated for short speech stimuli with the length of phonemes and a generic quality impairment, i.e. signal-correlated noise. It will be shown that a test set-up combining neurophysiological and subjective quality assessment methods for speech quality perception testing is suitable for measuring the perceived speech quality, and in some instances (trials) it is advanced in comparison to a standard subjective test set-up.

ERPs and Quality Ratings Evoked by Sentence Stimuli at Different Reverberation Levels

In this chapter (Chap. 4, Sentence Experiment), the generalization of the test set-up will be further applied to sentence-long stimuli at different reverberation levels. Therefore, a speech stimulus with the length of one sentence will be presented and—as degradation factors—different reverberation conditions will be employed.

Did you notice?: neuronal processing of multimodal mobile phone feedback

To acknowledge information received by a mobile device, a number of feedback modalities are available for which human information processing is still not completely understood. This paper focuses on how different feedback modalities are perceived by users introducing a test method that is new in this field of research. The evaluation is done via standard self-assessment and by analyzing brain activity [electroencephalogram (EEG)]. We conducted an experiment with unimodal and multi-modal feedback combinations, and compared behavioral user data to EEG data. We could show that EEG is a feasible method for quantifying conscious processing of feedback in different modalities as it correlates highly with subjective ratings. EEG can thus be considered an additional tool for assessing the effectiveness of feedback, revealing conscious and potential non-conscious information processing.