Comparison of PSDA and CCA detection methods in a SSVEP-based BCI-system

Using steady-state visually evoked potential (SSVEP) in brain-computer interface (BCI) systems is the subject of a lot of research. One of the most popular and widely used detection method is using a power spectral density analysis (PSDA). Lately there have been some new methods emerging, one of them is using canonical correlation analysis (CCA) which seems to have some promising improvements and advantages compared to traditional SSVEP detection methods, like better signal-to-noise ratio (SNR), lower inter-subject variability and the possibility to use harmonic frequencies, i.e., a serie of frequencies which have the same fundamental frequency. In this research two different SSVEP detection methods, one using PSDA and one using CCA are compared. The results show that the CCA-based detection method performs significantly better than the PSDA-based detection method. The increase of performance can in particular be seen when using harmonic frequencies. While the PSDA-based detection method has difficulties detecting harmonic frequencies, the CCA-based detection method is able to detect harmonic frequencies

Het raadselspel als rituele handeling

No Abstract

Enige opmerkingen over de tempel als " Heilige" en als "Gewyde" plaats

No Abstract

Rondom de Melanesische "Cargo Cults"

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Interview with Kristine Garnero Obbink, Portland Public School, 2013 (audio)

Interview of Kristine Garnero Obbink by Loraine Decker at 705 N. Killingsworth St., Portland, Oregon on May 14th, 2013. The interview index is available for download

Endotrophic mycorrhiza and the nutrition of grape vines

The roots of grape vines collected from a number of different localities throughout the Australian continent were all infected with mycorrhiza of the vesiculararbuscular type. Similarly a range of Vitis species and hybrids and a number of V. vinifera cultivars all displayed microscopic evidence of mycorrhizal infection.The growth of vine seedlings in soils sterilized either by autoclaving or by gamma irradiation was less than in similar non-sterile soil. The vine seedlings in sterile soils were not infected with mycorrhiza while those in non sterile were. Normal growth of vine seedlings in sterile soils was obtained by inoculating them with vine roots infected with live mycorrhiza. lnoculatio!1 of vine seedlings grown in sterile soils with roots containing dead mycorrhiza (autoclaved) or with filtered soil suspensions does not stimulate their growth. The shoots of vine seedlings grown In nori-sterile soil or in sterile soils and inoculated with live mycorrhiza had a significantly higher phosphorus content than seedlings not infected with mycorrhiza.i:t is suggested that in many of the habitats in which vines are grown in Australia and in Europe vesicular-arbuscular mycorrhiza aids their nutrition