• The Journal of the Acoustical Society of Korea
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• v.43 no.4
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• pp.422-435
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• 2024

This study intended to verify the effects of face masks on the Korean language in terms of acoustic, aerodynamic, and formant parameters. We chose all types of face masks available in Korea based on filter performance and folding type. Two professional voice actors (a male and a female) with more than 20 years of experience who are native Koreans and speak standard Korean participated in this study as speakers of voice data. Face masks attenuated the high-frequency range, resulting in decreased Vowel Space Area (VSA) and Vowel Articulation Index (VAI)scores and an increased Low-to-High spectral ratio (L/H ratio) in all voice samples. This can result in lower speech intelligibility. However, the degree of increment and decrement was based on the voice characteristics. For female speakers, the Speech Level (SL) and Cepstral Peak Prominence (CPP) increased with increasing face mask thickness. In this study, the presence or filter performance of a face mask was found to affect speech acoustic parameters according to the speech characteristics. Face masks provoked vocal effort when the vocal intensity was not sufficiently strong, or the environment had less reverberance. Further research needs to be conducted on the vocal efforts induced by face masks to overcome acoustic modifications when wearing masks.

• Journal of the Korean Geotechnical Society
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• v.21 no.4
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• pp.65-70
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• 2005

Many case histories of re-liquefaction phenomena seem to support the idea that sand deposits, if they once have been liquefied, could be reliquefied again by a subsequent earthquake even though the earthquake is smaller than the previous one. The magnitude of the strains induced in the initial liquefaction has a significant influence on the resistance of the sample to re-liquefaction. The deposits undergoing liquefaction experience large shear strain during liquefaction. And this previous strain changes the microstructure into highly anisotropic structure such as columnlike structure and connected voids. This type of anisotropy is so unstable that it can reduce re-liquefaction resistance. It is blown that the extent of anisotropic structural change depends on the gradation characteristics of ground. The purpose of this study is to estimate the correlation between the gradation characteristics of the sand and the ratio of re-liquefaction resistance to liquefaction resistance. In this study, 1-g shaking table tests were carried out on five different kinds of sands. During the tests the values of excess pore pressure at various depths and surface settlements were measured. Re-liquefaction resistances were not affected by the initial void ratio and the effective confining pressures, and the deposits of all test sands which had once been liquefied were reliquefied in the cyclic loading number below 1 to 1.5. The ratio of re-liquefaction resistance to liquefaction resistance linearly decreased as $D_{10}/C_u$ increased, and was constant as about 0.2 above the value of $D_{10}/C_u$, 0.15 mm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.1026-1038
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• 1995

Although aloe lost a lot of its previous popularity in modern clinical uses as medicine numerous scientific researches still have claimed the beneficial properties(curing and general tonic effect) of aloe gel. Whereas considerable contradictory reports have helped to confuse the aloe gel issue and continually aroused controversy about aloe gel efficacy. However health food, cosmetic and medicinal products made from aloe gel are widely available in the world market especially in U.S.A. so the growing of Aloe plant and the processing of A. vera gel have become big industries in some countries. In some previous papers the salicylic acid, one of the common trace gel components, was thought to have an analgetic and antinflammatory effect. Large amount of Mg ion in the gel was suggested to act as anesthetic, Mg-lactate as antihistamic, and Aloctin A(a glycoprotein) as wound healer by promoting the cell growth. The carboxypeptidase and bradykinase activity in the gel were proposed to have the pain relieving and antiinflammatory effect. But any of thes etheories concerining the physiological action of the trace gel components has not been demonstrated by modern pharmacology, and failed to be supported by clinical research. It was suggested by some research workers that trace amount of anthraquinone compounds in the gel play an important role to act as false substrate inhibitors for PG and TX production(antiprostanoid effect), by which, they believed, inflammation, burn and frostbite, and infected wound could be healed. This hypothesis has not been substantiated. Butthe suggested antimicrobial action, antidiabetic, and antidotic effect of aloe gel are likely to be attributed to the trace anthraquinone compounds. In a lot of recent experimental reports it has been claimed that aloe gel polysaccharides(acetylglucomannan, acetylmannan, and glycoprotein) have the antimicrobial, antinflammatory, antitumour, and infected wound healing effect by immunoenhancement. It is hoped that these effects will be soon documented in clinical studies, then the controversy on aloe gel beneficial effect will cease. In the 30 days subchronic toxicity test the lowest observed adverse effect level of acemannan(acetylmannan) on dog was 5.0 mg/kg, IP. But the aloe gel is generally agreed to be harmless and non toxic even for the internal use such as health food. In the case of idiosynrasy one must keep the delayed type hypersensitivity reaction of aloe gel in mind. In conclusion it seem to be impossible to simply refuse a lot of evidences made by research workers who have claimed aloe gel's beneficial effects and to deny the fact that there had been long therapeutic histories of Aloe plants.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.25-30
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• 2008

Purpose: In this paper, we have analyzed the problems of the Oh's report which is used to the basic data for supply and demand of medical technicians and studied a proposal for improvement to control system and supply and demand of korean optometrists. Methods: We have analyzed errors of Oh's report including supply and demand for medical technicians and management policy, expecting number for future optician, inaccurate estimation by limited data (employment rate, retirement rate, mortality rate) and an incorrect method of measurement for future supply and demand. Results: Oh's report showed the 18% error for estimation of supply which exclude the irregular entrance students. The estimation of supply was calculated by graduation rate 62.6% (college and University of Technology are 78.9% and 85.98% respectively), employment rate 65.8% (the average employment between 2002 and 2007 is 73.96%) and retirement rate is 2.3% (the retirement of pharmacists is 1.3%) but it showed the significant differences to objective data. For estimate the suitable ratio of optometrists to the population, the ratio use of medical facilities by an age group was used, and suggested spectacle wearers 1,280 persons (populations 2,928 persons) per optometrist but the different from reference of Germany (4,706 persons), America (1,789 persons) and Korea (1,825 persons/an optometrist) are applied to estimation on supply. This report applied the low employment rate and argued that maintain the present situation, but claimed that utilize unemployment persons. The above result has induced double weighting effect on estimation of supply. Conclusions: To solve the related problems of supply and demand, we have to make a search for exact data and optimum application model, have to take an example of nation similar job category as Germany and the research result of the job satisfaction into consideration. After we get the integrated research result, we must carried out the policy with fairness and balance for the estimation of supply and demand. Therefore exact research is required prior to beginning policy establishment, government and related group have to make a clear long-term plan and permanent organization for medical technician to establish supply and demand of medical technician.