Weyl-Heisenberg Spaces for Robust Orthogonal Frequency Division Multiplexing

Design of Weyl-Heisenberg sets of waveforms for robust orthogonal frequency division multiplex- ing (OFDM) has been the subject of a considerable volume of work. In this paper, a complete parameterization of orthogonal Weyl-Heisenberg sets and their corresponding biorthogonal sets is given. Several examples of Weyl-Heisenberg sets designed using this parameterization are pre- sented, which in simulations show a high potential for enabling OFDM robust to frequency offset, timing mismatch, and narrow-band interference

A study of gamification effectiveness

Studies have shown that gamification increases motivation and user experience when it comes to a certain behavior or completing a process. Gamification is often deeply associated with naïve animations and stylized text. This paper addresses the effect that visual representation has on the motivation of a subject by measuring their motivation after completing a mundane process, with entertaining gamification elements as well as gamification elements presented in plain text. For the purposes of this study a within subject design was used to gather data. Participants completed a mundane task three times, once without any gamification elements, once with pragmatic feedback and once with entertaining feedback. After completion the participants filled out the same Likert scale survey. The results were evaluated using the Wilcoxon Signed-Ranks test method, indicated that there was not a significant difference in user motivation between the visually stylized and plain text feedback. If conducted on a larger scale, this discovery could lead to a reduction time and cost for gamification development

Classification of Human Ventricular Arrhythmia in High Dimensional Representation Spaces

We studied classification of human ECGs labelled as normal sinus rhythm, ventricular fibrillation and ventricular tachycardia by means of support vector machines in different representation spaces, using different observation lengths. ECG waveform segments of duration 0.5-4 s, their Fourier magnitude spectra, and lower dimensional projections of Fourier magnitude spectra were used for classification. All considered representations were of much higher dimension than in published studies. Classification accuracy improved with segment duration up to 2 s, with 4 s providing little improvement. We found that it is possible to discriminate between ventricular tachycardia and ventricular fibrillation by the present approach with much shorter runs of ECG (2 s, minimum 86% sensitivity per class) than previously imagined. Ensembles of classifiers acting on 1 s segments taken over 5 s observation windows gave best results, with sensitivities of detection for all classes exceeding 93%.Comment: 9 pages, 2 tables, 5 figure