• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2821-2829
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• 2011

Since the KTX was in operation in 2004, a number of researches on increasing the train speed have been conducted. Currently, the Honam High-speed train system is designed for the operation velocity of 350km/h. The societal demand expects higher operation speed, whereas the existing construction method and design specification are questioned in the KTX operation in the velocity over 350 km/h. In this study, a full-scale model test was conducted to obtain the preliminary data that is necessary to understand deformation characteristics of the reinforced road bed and the subgrade layers. In the full-scale model test, direct arrival seismic tests, crosshole seimic test, in-situ bender element test and sensing bar test were employed to measure the stiffness and deformation of the trackbed. The systematic analysis on the different set of measurements enhances the understanding of the behavior of the trackbed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1542-1549
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• 2009

The function of subgrade in the railway is to support track load on the subgrade as well as train load. Unlike the traditional railway, the uppermost subgrade layer in the Gyeongbu high speed railway was constructed as the reinforced road bed. The reinforced road bed comprises sub-ballast in the upper part and grade ballast in the lower part. The filling material such as soil and rocks in the subgrade can be settled by consolidation of original ground, compression due to self weight, plastic displacement due to train operation, and unequal settlement due to embankment material or improper compaction, therefore many efforts have been given for sufficient compaction and use of proper filling materials in the construction stage. The purpose of this study is to investigate the deformation state of subgrade in the Gyeongbu high speed railway. The investigation on the subgrade settlement was performed by choosing representative sections suspected to be settled based on the previous GPR test results and track maintenance history, measuring the settlement for some time period after installing settlement measuring instruments on and under the reinforced road bed. and analyzing the long-term subgrade settlement data from monitoring system which was installed at the construction stage of the high speed railway.

• Structural Engineering and Mechanics
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• 제9권4호
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• pp.375-382
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• 2000

Experimental investigation into the cyclic behaviour of sand plast brick masonry was performed on forty two square panels. The panels were subjected to cyclic uniaxial compression for two cases of loading: normal to bed joint and parallel to bed joint. Experimental data were used to plot the unloading-reloading curves for the entire range of the stress-strain curve. Mathematical expressions to predict the reloading and unloading stress-strain curves at various values of residual strain are proposed. A simple parabola and an exponential type formula are found adequate to model the unloading and reloading curves respectively. The models account for the potential effects of residual strain on these curves. Comparison of test results with the proposed mathematical expression shows good correspondence.

• 한국환경보건학회지
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• 제24권3호
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• pp.41-47
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• 1998

The purpose of this research is evaluation of adsorption capacity of the cast for TCE comparing with the yellow clay. Furthermore, the experimental data was fitted with the Langmuir and Freundlich isotherm and was found to be apllicable to the adsorption isotherm equation. The soil bed reactor used in this study was made of glass(10 cm in diameter, 100 cm in depth). The cast and yellow clay used as adsorbents were screened with 8-20 mesh mecanically. Results from Equilibrium test with adsorbents showed that the equibrium time of the cast and yellow clay was 9min independent of the amount of the adsorbents. The adsorption efficiencys of the cast and yellow clay for TCE was 66.3% and 56.2%, respectively. In the application of Freundlich isotherm, 1/n of the cast and yellow clay were 0.786 and 0.704, respectively. These results showed that the cast was more available than the yellow clay as TCE adsorbent. The best adsorption capacity was showed at 0% moisture content, 70 ppm inlet concentration and 25$^{\circ}$C temperature.

• Computers and Concrete
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• 제9권5호
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• pp.375-387
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• 2012

The objective of this investigation was to develop rules for automatic categorization of concrete quality using selected artificial intelligence methods based on machine learning. The range of tested materials included concrete containing a new waste material - solid residue from coal combustion in fluidized bed boilers (CFBC fly ash) used as additive. The rapid chloride permeability test - Nordtest Method BUILD 492 method was used for determining chloride ions penetration in concrete. Performed experimental tests on obtained chloride migration provided data for learning and testing of rules discovered by machine learning techniques. It has been found that machine learning is a tool which can be applied to determine concrete durability. The rules generated by computer programs AQ21 and WEKA using J48 algorithm provided means for adequate categorization of plain concrete and concrete modified with CFBC fly ash as materials of good and acceptable resistance to chloride penetration.

• 보건의료산업학회지
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• 제8권2호
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• pp.1-10
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• 2014

This study examined nonpatient revenues of university hospitals in korea. The data source for this study was 22 university hospitals over the period 2010-2012. In this study, patient revenues, patient expenses, operating profit, nonpatient revenues, total revenues, operating margin, normal profit to gross revenues, ratio of the nonpatient revenues in the total revenues were analysed by the annual and three-year average. The analysis of nonpatient revenue differences by hospital type, bed size, location, management performance was performed by T-test and oneway ANOVA. The results were as follows. First, nonpatient revenues of university hospitals were increased during the period 2010-2012. Second, nonpatient revenues according to hospital type, bed size, location in the university hospitals had significant difference. Third, hospital type was significantly associated with normal profit to gross revenues which was profitability index about nonpatient revenues. Based on these results, this study suggests implications to diversify for management performance in hospitals.

• 한국공작기계학회논문집
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• 제10권5호
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• pp.31-38
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• 2001

This paper deals with the micro turning property of setting angle using diamond tool. The bed of the system has used the granite which has the thermal and vibrational characteristics superior to the cast iron bed for the common machine tool. To minimize the inner and outer vibration of the fuming system, an air pad system was manufactured and tested. The aero-static spindle system which has the excellent rotation accuracy was designed and manufactured. As a result of the micro-cutting test on aluminum alloy, tool setting angel have effected on surface roughness. From the results, the micro-cutting conditions hope to provide the useful actual data using in industrial fields.

• 한국병원경영학회지
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• 제14권2호
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• pp.1-20
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• 2009

The purpose of this study is to find the determinant variables to make profitability in regional public hospitals. The data come from financial statements and annual reports of 34 regional public hospitals for five years (from year 2003 to year 2007). The T or F-test and hierarchical multiple regression analysis are used. The dependant variables are the profitability indicators, ordinary income to total asset and operating margin to gross revenue, and the independent variables are general characteristics, diagnosis and treatment patterns, financial and public benefits. The findings of this study are summarized as follows. First, Variables affecting the profitability indexes revealed from DEA results is the bed occupancy rate, number of hospitalized patients to outpatients, ratio of first medical examination for outpatients, number of daily patients per medical specialist, labor cost per patient and managerial expenses per patient. Second, the ordinary income to total asset representing the asset usage performance is affected by the average hospitalized days, bed occupancy rate, labor cost per patient and ratio of patients with medical insurance coverage. Third, the operating martin to gross revenue obtained from the actual operations of hospitals has its significance with the bed occupancy rate, number of hospitalized patients to outpatients, managerial expenses per patient and public benefit indicator. This study has some restriction not to use pannel data analysis, although it used data for five years. Accordingly, various additional studies should be done to supplement such problems.

• 한국항공우주학회지
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• 제34권11호
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• pp.84-91
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• 2006

최근에 인공위성용 전자소자는 우주방사선에 좀 더 강한 소자를 요구되어진다. 왜냐하면, 인공위성의 수명과 기능은 우주방사선으로부터 영향을 받기 때문이다. 또한, 과거에는 부품단위의 우주방사선 시험을 수행하지 않고 유닛 또는 서브시스템 단위의 우주방사선 시험을 수행하였다. 게다가, 발사된 인공위성이 작동오류 상태에 있을 때 그 이유를 분석하기에는 그다지 쉬운 일은 아니다. 따라서, 발사 전 부품 단위 우주방사선 시험을 수행하여 주요 소자에 대한 우주방사선에 의한 영향을 분석 할 필요가 있으며, 지상에서 데이터를 확보할 필요가 있다. 그러므로, 본 논문에서는 모든 전자소자의 기본이라 할 수 있는 금속-산화막 반도체 전계효과 트랜지스터의 총이온화선량에 대한 영향 시험을 수행하기 위한 테스트 베드를 제안한다.

• 기본간호학회지
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• 제18권2호
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• pp.195-200
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• 2011

Purpose: The purpose of this study was to assess rates for handwashing adherence before and after nursing contact in intensive care units (ICU). Methods: The participants included 90 nurses working in intensive care units of an 800-bed university-affiliated hospital in Gyeonggi Province and 2000-bed university-affiliated hospital in Seoul. Time for handwashing was calculated using the average number of handwashings during an 8-hour day shift. Nursing contact was based on indications as defined by the Centers for Disease Control and Prevention (CDC, 2002). Data were analyzed using frequency, percent, t-test and ${\chi}^2$-test. Results: During an 8-hour day shift, the average number of times that hands were washed was 25.0. The rates were significantly lower before the nursing contact than after the nursing contact when it involved sectioning, observation or contact with a wound, cleaning enteric feeding bag, physical exam, use of gloves, or contact with contaminants. Conclusions: The results indicate that as handwashing rates were significantly lower before nursing contacts than after nursing contacts, there is need to develop strategies to address this deficiency in handwashing.