• Geomechanics and Engineering
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• 제24권6호
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• pp.519-529
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• 2021

In coal mining activities, the abutment stress of the coal has to undergo cyclic loading and unloading, affecting the strength and seepage characteristics of coal; additionally, it can cause dynamic disasters, posing a major challenge for the safety of coal mine production. To improve the understanding of the dynamic disaster mechanism of gas outburst and rock burst coupling, triaxial devices are applied to axial pressure cyclic loading-unloading tests under different axial stress peaks and different pore pressures. The existing empirical formula is use to perform a non-linear regression fitting on the relationship between stress and permeability, and the damage rate of permeability is introduced to analyze the change in permeability. The results show that the permeability curve obtained had "memory", and the peak stress was lower than the conventional loading path. The permeability curve and the volume strain curve show a clear symmetrical relationship, being the former in the form of a negative power function. Owing to the influence of irreversible deformation, the permeability difference and the damage of permeability mainly occur in the initial stage of loading-unloading, and both decrease as the number of cycles of loading-unloading increase. At the end of the first cycle and the second cycle, the permeability decreased in the range of 5.777 - 8.421 % and 4.311-8.713 %, respectively. The permeability decreases with an increase in the axial stress peak, and the damage rate shows the opposite trend. Under the same conditions, the permeability of methane is always lower than that of helium, and it shows a V-shape change trend with increasing methane pressures, and the permeability of the specimen was 3 MPa > 1 MPa > 2 MPa.

• 한국지반공학회지:지반
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• 제6권1호
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• pp.43-58
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• 1990

지반앵커의 극한인기저항흉을 구하기 위해서는 파괴면의 위치, 파괴면 위의 수직응력 및 마찰각 을 알지 않으면 안된다. 본 연구에서는 평면변형률 모형실험을 통해서, 앵커주변지반의 변형을 관찰하여 파괴면의 위치를 구하고, 앵커표면의 수직응력,전단응력을 실측하므로써 앵커표면의 응력상태를 분석했다. 그리고, 측압계수와 파괴면의 위치의 관계(파괴모-드)를 구하구 무차원 계수인 극한인발저항력계수를 이용하여 극한51기저항력의 산정식을 제안했다.

• 한국응급구조학회지
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• 제11권3호
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• pp.65-79
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• 2007

Purpose : It was to find out demand and supply of EMT from 2007 to 2045 and to expand scope of practice of paramedic in Korea. Methods : This study was conducted by applying a projection formula to the data from admission quota for EMT of the Ministry of Education & Human Resources Development, rate of successful candidates of annual report of the National Health Personnel Licensing Examination Board etc. Results : The number of EMTs were 6,043 paramedics, 5,378 EMT-Bs until 2006 and two produce constants derived from simple estimation were paramedic 0.81, EMT-B 0.86. On the American basis of 5.6 EMTs per 10,000, the number of paramedics under the present act will reach the basis around 2015(5.02), the number of paramedics under the amended act will reach the basis around 2030(5.50). Conclusion : There was relationship between scope of practice of paramedic in the act and demand-supply of paramedic, this necessitates surveys, studies, amendment of the act, legalization for expanded scope of practice of paramedic.

• The Journal of Asian Finance, Economics and Business
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• 제7권12호
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• pp.795-807
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• 2020

The more liquid the capital market, the more attractive it will be for investors to place their money in the capital market. Therefore, the purpose of this study is to investigate the factors that influence stock liquidity of manufacturing sector companies listed on the stock exchange in Indonesia. The independent variables used in this study are forward-looking information disclosure, institutional ownership, foreign ownership, and board activity with information asymmetry as an intervening variable and stock liquidity as the dependent variable. The population of this study is manufacturing sector companies listed on the Indonesian stock exchange (IDX). Samples are selected based on the random sampling method, and the number of samples is calculated based on the Slovin formula. The sample was 59 manufacturers, and data was annual reports (for 2 years) and stock transactions from 2016 to 2017. The results of the study showed that forward-looking information disclosure had a significant effect on information asymmetry. Information asymmetry and foreign ownership have a significant impact on stock liquidity, whereas information asymmetry mediates the relationship between forward-looking disclosures and stock liquidity. Furthermore, the accuracy of information about the certainty of business activity both now and in the future can instill confidence in stakeholders in interacting and cooperating.

• 한국컴퓨터정보학회논문지
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• 제9권3호
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• pp.135-141
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• 2004

소프트웨어의 종류가 다양하고, 커짐에 따라서 유지 보수 문제는 더욱 복잡하고 어렵게 되고, 프로그램 에러의 교정이나 요구 사항의 변경, 사용자에 대한 요구가 점차 증가되면서 소프트웨어의 유지 보수가 소프트웨어 생명 주기에서 가장 비용을 많이 차지하는 부분이 되었다. 본 논문에서는 객체지향 시스템에서 소프트웨어 재구성 환경을 위한 역공학 도구를 설계, 구현하였다. 이 도구는 클래스 정보를 이용한 규칙기반 역공학 도구이다. 프로그램 유지보수자가 프롤로그를 이용한 시스템 쿼리를 사용할 수 있도록 하였다. 대부분의 유사한 클래스를 추출하기 위한 재구조화 방법과 변수와 함수 사이의 관계에 근거를 둔 방법을 사용하였다. 추출된 클래스의 가시성이 자동적으로 산출되고, 논리언어를 이용한 쿼리를 사용함으로서 실질적인 유지보수가 이루어지도록 하였다. 또한 이 도구를 평가하는 방법을 제안하였다.

• 한국환경과학회지
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• 제10권6호
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• pp.445-450
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• 2001

This study was carried out In Investigate the correlation between toluene In air and hippuric acid In human urine, which 1.: based on the results of the health check-in and the measure of working environment, was investigated for two years. The concentration of toluene in air for the five working places in Yang-San area were ranged from 39.05±10.31 ppm to 4.04±3.38ppm and the mean value of those was 16.89±14.76ppm. The mean value was 16.89±14.76ppm which is below the permissible limit of toluene. The concentration of hippuric acid(HA) In the worker's urine were between 0.47g/ℓ and 0.76g/ℓ. There was mutual correlation (Υ=0.94) between the concentration of toluene in air and that of hippuric acid in urine. In case of male workers, the mean value of hippurlc acid In urine was 0.56g/ f and the female workers was 0.57g/ℓ that showed higher than the male's. However, there was no relationship between the workshop and the distinction of sex. From the mean value of toluene in air(T) and that of hippuric acid(H), we obtained the formula, Η=0.3logΤ+0.235.

• 복식문화연구
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• 제4권3호
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• pp.395-406
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• 1996

This article aims, by analyzing structurally the codification of dress sign in Korean society, the signifying system of the codes and their message communicated, to make clear a signifying structure that would be codified through the relationship between abstract concepts and real condition of dress. I used the semiotic theory of Ferdinand de Saussure′s conception on structuralismly the codification, cultural semiology of Roland Barthes and Myung-Sook Han′s formula of dress structure as tools analyse may objective of wedding dress of folks in Choson Dynasty, which has been successive our traditional Korean wedding dress. My results of the study are : The procedure of wedding ceremony in Choson Dynasty was presented in texts like Juga-garye, Sarye-peonram and Kukjo-orye, its dress system has been more emphasized on language, and aspect of social system, than parole, one of individual realization. In addition, the meanings of marrage such as "Oneness of bride and bridegroom", "Mixture of two sexes", "Blessing of good luck", were included in the signified like the style, pattern and color of the wedding dress, and specially, pattern and color, the articulated morphemes, was emphasized, When we combinated terms of dress in Choson Dynasty with syntagmatic, regarding their list as paradigmatic, it will signify a wedding dress, and according to combinating ways, it amy be divided as sign of dresses of bride and bridgeroom by sex or king, gentry and common people by class. Wedding Dress in Choson Dynasty = [{ODx(U/Dxu/d)}+AC·H·FW].

• 지질공학
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• 제29권4호
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• pp.393-403
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• 2019

취수보의 저류성능은 유량과 수심의 관계로 평가될 수 있다. 돌망태 취수보의 유량과 수심의 관계는 채움재의 물리적 특성에 따라 달라진다. 본 연구에서는 인공함양 원수확보를 위한 돌망태 취수보의 저류성능을 평가하는데 활용할 기존의 방류량 산출식들을 검토하였다. 채움재의 물리적 특성을 실험변수들과 관계식으로 표현한 기존의 방류량 산출식은 유량과 수심의 관계를 잘 표현하였다. 또한 채움재의 평균입경은 수심확보와 간접취수에 영향을 미치기 때문에 저류성능 뿐 아니라 취수성능에도 중요한 인자임을 알 수 있었다.

• 한국항해학회지
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• 제9권1호
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• pp.41-81
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• 1985

Tidal phenomenon can be utilized by the wise and cautious mariner to safely perform his duties as pilot and navigator. It can be either a help or hindrance to the mariner. The principle of MULDAE which expresses the determination of the state of the tide based upon knowledge of the lunar date and it has been used in Korea since ancient times. The folk method of calculation was essentially based on an unsystematic division of the lunar month, traditionally using the numbers 7 or 8. As the lunar cycle is complete in 15 days the tidal cycle should also correspondence closely to the lunar date. This paper represents the first scientific attempt to systematically investigate this unique traditional method of tidal calculation and contains a comparison of the MULDAE and ordinary (solar based) tide calculation methods. MULDAE was compared with the standard tide table for standard and island ports in Korea from 1982 to 1985. This study concluded that MULDAE was indeed an accurate adn reliable predictor of tidal activity. Furthermore, the number 6 was found to be the correct divisor upon which to base MULDAE calculations Also a formula expressing MULDAE as a function was discovered. This research show that MULDAE can be applied nationwide and is a reliable and easy way to predict tides based upon mean figures for certain ports and island A calender showing MULDAE is presented here for the first time. A clear relationship between the MULDAE method of calculating tides and the use of ordinary tide tables is proven.

• Journal of Chest Surgery
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• 제17권4호
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• pp.644-656
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• 1984

In Tetralogy of Fallot, the most common congenital cyanotic heart disease, the mortality is decreasing continuously with adequate type and timing of operation. At S.N.U.H., 195 patients were operated from January 1982 to December 1983 and 176 patients among them were analysed in the view of pre-operative pulmonary arterial condition measured by cardiac cineangiogram. The most common associated anomaly was PFO and ASD and they did not affect the postoperative course and mortality. The overall mortality rate was 8.5% in 1982 and 6.8% in 1983 but under 2 years of age, the mortality rate was relatively high as 25% in 1982 and 16.7% in 1983, and when transannular patch widening of Right Ventricular Outflow Tract was used, the mortality rate was 12.5% in 1982 and 27.3% in 1983. Preoperative angiographic measurements of the pulmonary arterial status for prediction of the ratio between the Left Ventricular and Right Ventricular peak systolic pressure were calculated retrospectively according to the Blackstones formula, and the predicted value of PRV/LV greater than 0.6 carried apparently high complication and mortality rate as 16.6% M.R. in 1982 and 11.1 % in 1983. Among postoperative complications, c-RBBB occurred most frequently about 50% but did not influenced to mortality, Low Cardiac Output Syndrome was developed in about 40%. If we select the patient who should have the staged operation including shunt operation and choose the type of RVOT relief, we expect the improvement of postoperative clinical results.