• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.543-548
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• 2002

Nowadays since the customers of HDD's are interested in their noise levels in addition to their primary performances such as their average access time, capacity, HDD manufacturers make efforts on reducing the noise. The works to reduce noise are usually based on the measurable physical quantities such as SPL or acoustic intensity level. However, since the HDD noise is Judged by human beings, the basis of noise reduction should be human sensations. In this paper, the noise levels of various HDD's are evaluated by the human jury test to find a relationship between the physical quantities used for noise control and the human sensations of noise. Discrepancies are found in the judgments by the human beings and by the physical quantities. The loudness level, a psychoacoustic variable, is used to solve the discrepancy.

• Sleep Medicine and Psychophysiology
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• v.13 no.1
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• pp.27-32
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• 2006

Objectives: Nasal continuous positive airway pressure (nCPAP) is the treatment of choice and has been shown to reduce the frequency of nocturnal respiratory events, improve sleep architecture, and decrease daytime sleepiness in patients with obstructive sleep apnea syndrome (OSAS). However, little is known about the compliance of nCPAP treatment in Korea. Our objective was to look into the nCPAP compliance and examine the factors influencing it. Methods: We reviewed the records of one hundred and twenty consecutive patients with OSAS referred for nocturnal polysomnography with nCPAP pressure titration during the period of January 1995 through April 1999 to the Seoul National University Hospital. We performed a telephone interview and obtained data from eighty-three patients. Results: In sixty patients who had accepted nCPAP treatment, twenty-six patients (43.3%) were still using nCPAP device, while thirty-four patients (56.7%) stopped using it. Fifteen patients (25%) were using nCPAP device everyday. In thirty-four patients who discontinued nCPAP use, twenty-five patients (73.5%) did within the first three months, and thirty-one (91.2%) within the first year. Significant predictor of long-term nCPAP use was the presence of subjective daytime sleepiness before nCPAP application. Conclusions: Long-term compliance with nCPAP treatment appears to be associated with the presence of subjective daytime sleepiness before nCPAP application. Long-term compliance with nCPAP may be mostly predicted from the usage pattern within the first three months of use.