No abstract

No abstract

This paper proposes a new objective metric of exceptional motion in VR video contents for VR sickness assessment. In VR environment, VR sickness can be caused by several factors which are mismatched motion, field of view, motion parallax, viewing angle, etc. Similar to motion sickness, VR sickness can induce a lot of physical symptoms such as general discomfort, headache, stomach awareness, nausea, vomiting, fatigue, and disorientation. To address the viewing safety issues in virtual environment, it is of great importance to develop an objective VR sickness assessment method that predicts and analyses the degree of VR sickness induced by the VR content. The proposed method takes into account motion information that is one of the most important factors in determining the overall degree of VR sickness. In this paper, we detect the exceptional motion that is likely to induce VR sickness. Spatio-temporal features of the exceptional motion in the VR video content are encoded using a convolutional autoencoder. For objectively assessing the VR sickness, the level of exceptional motion in VR video content is measured by using the convolutional autoencoder as well. The effectiveness of the proposed method has been successfully evaluated by subjective assessment experiment using simulator sickness questionnaires (SSQ) in VR environment.

No abstract

An ascorbic acid tolerance test is described for assessing vitamin C status. The test is simple to administer and suitable for elderly patients. It involves giving an oral load of 1 g ascorbic acid in water and then measuring urinary excretion of vitamin C over the next 6 h. The excretion pattern at dosing has been studied in ten young subjects. The result of the ascorbic acid tolerance test in these young subjects was significantly different after supplementation with 1 g ascorbic acid daily for 1 month. Two series of elderly patients were also studied with the ascorbic acid tolerance test. They had low initial plasma ascorbic acid levels and much less vitamin C was excreted in the urine after dosing. Seven of these elderly patients were then supplemented with 1 g ascorbic acid for 1 month. After supplementation the initial plasma levels and their response to the ascorbic acid tolerance test became similar to that seen in younger subjects.