Visible light communication (VLC) will play a wide variety of important roles in future communication services. This paper deals with color shift keying (CSK) for the modulation of visible light communications. There are some previous studies about psychological and physiological effects of colors. These studies implied that color offset CSKs have psychological and physiological effects, which normal CSK doesn't have. This paper evaluates the psychological and physiological effects of color offset CSKs compared with normal CSK based on interviews and electroencephalogram (alpha wave, beta wave, and P300) measurements. This study evaluates the feasibility of visible light communication providing added value by measuring arousal, rest, visual attraction, task performance, capacity of working memory, and response for the CSK codes. The results showed that red-, green- and blue-offset CSK have specific features. Red-offset CSK induces excitement and increasing wakefulness levels, attracts attention, enlarges capacity of working memory, raises task performance, and induces fast responses. Green-offset CSK maintains rest levels, elevates relaxation levels, reduces stress, raises task performance, and induces fast responses. Blue-offset CSK maintains rest levels and induces fast responses. It is thought that we can use color offset CSK appropriately and provide added value to their application by considering the results of psychological and physiological investigations. Red-offset CSK is thought to be suitable for commercial advertisements. Green- and blue-offset CSK are thought to be suitable for wireless communication environments in hospitals. Red- and green-offset CSK are thought to be suitable for wireless communication environments in business. Red-, green- and blue-offset CSK are thought to be suitable for use in intelligent transportation systems (ITS).

The present study examined the evaluation of aging using the photic driving response, a measure used in routine EEG examinations. We examined 60 normal participants without EEG abnormalities, classified into three age groups (2029, 3059 and over 60 years; 20 participants per group). EEG was measured at rest and during photic stimulation (PS). We calculated Z-scores as a measure of enhancement and suppression due to visual stimulation at rest and during PS and tested for between-group and intraindividual differences. We examined responses in the alpha frequency and harmonic frequency ranges separately, because alpha suppression can affect harmonic frequency responses that overlap the alpha frequency band. We found a negative correlation between Z-scores for harmonics and age by fitting the data to a linear function (CC: -0.740). In contrast, Z-scores and alpha frequency were positively correlated (CC: 0.590).

The objective of this paper is to study the relationship between a visual stimulus and the amplitude and phase of the alpha wave as a first step to investigating a change in the background wave after a sensory stimulus and an evoked potential. We examined the effect of a single visual stimulus on the amplitude and phase of alpha waves using the complex demodulation method. The visual stimuli were generated by an LED mounted in goggles with the eyes-closed condition. The amplitude of the alpha wave decreased gradually after the stimulus, until it reached a minimum at around 300 ms after the stimulus. The alpha wave continued to increase, showing some rebound, and returning again to the pre-stimulus level. The phase variation after the stimulus tends to be considerably larger than that before the stimulus. Moreover, the average phase returned to the same slope as the pre-stimulus by 2550 ms after the stimulus. The visual stimulus has an effect on the alpha wave until about 2500 ms after the stimulus. The phase variation difference before and after stimulus is significant from 112 ms to 678 ms after the stimulus. This finding suggests there is a partially pararell time course between the change in VEPs plus ERP complex and the alpha wave.