• 한국지반신소재학회논문집
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• 제12권4호
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• pp.1-10
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• 2013

최근들어, 사용 종료된 폐기물 매립장을 공원 및 체육시설로 활용하는 사례가 증가하고 있으며, 사용종료 매립장 활용을 위해서는 일차적으로 환경영향 여부와 구조적 안정성이 중요하다. 특히 상부구조물 설치 시 지지력 및 침하에 대한 안정성을 확보하여야 하며 폐기물 매립지반의 침하에 대한 안정성 확보와 지지력 보강을 위하여 토목섬유(지오셀)을 포설하기도 한다. 본 논문에서는 사용 종료된 폐기물 매립장의 장기침하 계측결과 분석 및 매립지반에 대한 지오셀 보강 시 지지력 보강효과에 대하여 분석하였다. 장기침하 분석은 매립장의 현장계측 침하량과 쓰레기 침하 모델식별 산정된 침하량을 비교하였고, 각 모델식별로 침하량에 가장 큰 영향을 미치는 파라메타를 분석하였다. 본 연구결과에 따르면, Park모델식에 따른 예측침하량($C_{intermediate}$ = 0.0678)이 현장계측 침하량과 가장 유사한 경향을 나타내었다. 또한, 지오셀 보강에 따른 지지력 증가는 무보강 지반에 비하여 약 1.193~1.554배 증가되는 것으로 도출되었다.

• 생물환경조절학회지
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• 제24권3호
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• pp.187-195
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• 2015

본 연구에서는 내재해형 플라스틱 온실과 유리온실의 기초에 대하여 인발저항력을 검토하기 위해 사질토 지반에서 실규모로 제작한 총 15개의 온실 기초를 이용하여 현장시험을 실시하였다. 그 결과, 대상 온실 기초의 최대인발저항력은 기초의 형태 및 규모가 서로 상이함에 따라 11.6 kN~82.4kN의 범위로 나타났다. 온실기초의 최대인발저항력 산정을 위해 제안된 이론식에 대하여 현장시험 결과를 이용하여 적용성을 검토한 결과 전반적으로 기존의 산정 이론식이 현장시험결과와 근접하는 수치를 제공하는 것으로 검토되었다. 다만, 본 연구에서 고려한 지반은 사질토 지반이며, 향후 점성토지반에 대하여 기존의 인발저항력 산정 이론식의 검증이 필요할 것으로 판단된다.

• 한국지반신소재학회논문집
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• 제8권1호
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• pp.33-40
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• 2009

본 논문에서는 도로를 보강하는 토목섬유 중 지오셀을 이용하였을 때의 보강효과를 알아보기 위해서 실내시험과 현장시험을 실시하였다. 실내 시험은 실대형 직접전단시험기와 모형토조 직접전단시험기를 이용하여 수직응력에 따른 전단응력 곡선을 산정하고 이를 통해 지오셀이 점착력과 내부마찰각을 증가하는 효과를 볼 수 있었다. 실내시험의 결과값을 Terzaghi 공식과 Meyerhof의 공식을 이용하여 극한지지력값을 계산하고 현장시험에서 확인한 극한 지지력값과 비교하여 지오셀의 보강효과를 확인하였다. 분석결과, 직접전단시험을 통해 지오셀의 보강효과가 내부마찰각의 증가에 영향을 미치는 것을 확인하였다. 또한 셀의 개수가 커질수록 내부마찰각이 커짐을 확인하여 보강면적이 넓을수록 보강효과가 증가하는 것으로 나타났다. 지지력에 미치는 영향요소중 내부마찰각을 증가시키는 지오셀을 도로저부에 시공할 경우 내부마찰각의 증가로 지지력 또한 증가하는 것을 확인하였으며, 평판재하시험의 결과값을 통해 지오셀보강이 극한지지력값의 증가효과에 2배정도의 보강효과를 확인하였다. 수치해석을 통해 변형의 분포와 침하량을 확인한 결과, 침하량은 지오셀에 의해 줄어드는 결과를 보여 침하에 대한 보강효과를 확인하였다.

• 한국지열·수열에너지학회논문집
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• 제10권3호
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• pp.17-23
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• 2014

One major breakthrough in the field of heating, ventilation and air conditioning has been the development of heat pumps. Heat pump systems offer economic alternatives for recovering heat from different sources for use in various industrial, commercial and residential applications. In recent years, the heat pump has been tipped to have a very good potential for hot water production. This paper investigated the performance of a vapor injection heat pump with the variation of sub-cooler capacity at heating mode. The heating capacity of the vapor injection heat pump slightly increased with an increment of sub-cooler capacity, while COP didn't increase continuously. The 20% capacity of sub-cooler comparing with system capacity could be used as a standard to select sub-cooler capacity.

• Earthquakes and Structures
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• 제12권1호
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• pp.23-34
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• 2017

Composite steel plate deep beam (CDB) is proposed as a lateral resisting member, which is constructed by steel plate and reinforced concrete (RC) panel, and it is connected with building frame through high-strength bolts. To investigate the seismic performance of the CDB, tests of two 1/3 scaled specimens with different length-to-height ratio were carried out under cyclic loads. The failure modes, load-carrying capacity, hysteretic behavior, ductility and energy dissipation were obtained and analyzed. In addition, the nonlinear finite element (FE) models of the specimens were established and verified by the test results. Besides, parametric analyses were performed to study the effect of length-to-height ratio, height-to-thickness ratio, material type and arrangement of RC panel. The experimental and numerical results showed that: the CDBs lost their load-carrying capacity because of the large out-of plane deformation and yield of the tension field formed on the steel plate. By increasing the length-to-height ratio of steel plate, the load-carrying capacity, elastic stiffness, ductility and energy dissipation capacity of the specimens were significantly enhanced. The ultimate loading capacity increased with increasing the length-to-height ratio of steel plate and yield strength of steel plate; and such capacity increased with decreasing of height-to-thickness ratio of steel plate and gap. Finally, a unified formula is proposed to calculate their ultimate loading capacity, and fitting formula on such indexes are provided for designation of the CDB.

• 간호행정학회지
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• 제21권3호
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• pp.308-316
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• 2015

Purpose: The purpose of this study was to identify the level of project perception for those nurses from research-driven hospitals and to analyze the effect of research-relevant performance in the health care field focusing on the mediated effect of research capacity and job satisfaction. Methods: Data were collected from June, 2014 to July, 2014, and participants were 106 research nurses in Research-driven hospitals. Descriptive statistics, Independent t-test, One-way ANOVA, structural equation modeling (SEM). Results: As a result, Research-relevant performance according to project perception of research nurses from Research-driven Hospitals was not statistically significant, but research capacity and job satisfaction had a mediating role. Evaluation System Perception was significantly different from Research Capacity (p<.001), Research Capacity was significantly different from Job Satisfaction (p<.001), Job Satisfaction was significantly different from Research Performance (p<.001) Conclusion: The results indicate that research capacity building and job security research nurses are able to contribute to improving research performance of research-driven hospitals.

• 한국군사과학기술학회지
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• 제18권4호
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• pp.402-408
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• 2015

Protection against direct projectiles has been adapted just to the main command posts in the existing protective facility standards. However, protective capacity for the shelters against direct projectiles is also required because the initial survivability as well as the operation sustainment of the shelters is critical during a couple of days from outbreak of war. In this study, the Russian artillery is used to determine the existing and future threat of the North Korean Armed Forces indirectly. And then, required protective capacity of military shelters in the contact areas is calculated along with UFC 3-340-02 and it is verified using modeling and simulation. Based on the assessed capacity, actual inspect of military facilities with contact areas on spot is performed whether military shelters have enough protection capacity against determined threats. According to the field study, it is verified that proper earth bermed shelter has enough protection capacity. The results in this study could be used how to retrofit the current shelters in the contact areas.

• 한국지반환경공학회 논문집
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• 제18권9호
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• pp.19-31
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• 2017

미국 사례의 경우 항타말뚝과 현장타설말뚝은 동재하시험과 정재하시험 지지력 상관관계 분석에서 좋은 상관관계를 나타내었다. 하지만, 국내에서는 해외에서 많이 사용하지 않는 매입말뚝으로 주로 시공을 하고 있으며, 매입말뚝의 동재하시험 신뢰성에 대해 의문이 많아 동재하시험의 신뢰도를 확인하고자 하였다. 본 연구에서는 LH 현장(천안, 인천, 의정부)에서 PHC 매입말뚝에 대하여 재하시험을 실시하였으며, 동재하시험(EOID 7회, Restrike 7회)과 정재하시험(7회) 지지력을 비교 분석하였다. 그 결과 재항타동재하지지력 및 정재하지지력 평균 값 비교 시 정재하지지력 평균 값이 약 27% 높게 나타났다(신뢰도 : 0.73, 변동계수 : 0.3). 재항타지지력(Davisson 판정 값) 및 정재하지지력(Davisson 판정 값) 평균 값 비교 시 정재하지지력(Davisson 판정 값) 평균 값이 약 27% 높게 나타났다(신뢰도 : 0.73, 변동계수 : 0.2). 동재하시험과 정재하시험의 차이를 줄이고자 본 연구에서는 수정동재하지지력(EOID의 극한선단지지력+Restrike의 극한주면마찰력)을 제시하였으며, 수정동재하지지력과 정재하지지력을 비교했을 때는 그 차이가 9%로 줄어들었다(신뢰도 : 0.91, 변동계수 : 0.2). 또한 변동계수가 0.2로 줄어들어 일관성이 증가한 것으로 나타났다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.227-230
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• 2009

In this paper, the results of field testing of high-speed power line in-home networking in Korea are reported. When multiple networks share a common channel, they can interfere destructively and reduce system capacity. This is major problem in-home power line communications, especially in MDU deployments. The effects of neighboring network interference in power line communications are reported.

• Agricultural and Biosystems Engineering
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• 제3권2호
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• pp.73-78
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• 2002

Cabbage is one of the most important vegetable in Korea. The cabbage production was mainly based on human labor A comprehensive research fur substituting the human labor by machines has been performed until now. In general, cabbage is cultivated on hillside in Korea. Picking up the harvested cabbages in field and carrying to a vehicle fur transportation are very laborious work. Manual transportation of cabbage is likely to damage the quality and is also a cause to increase the cost of cabbage production. This study was to develop and evaluate a prototype cabbage loader fur efficient and safe transportation of cabbage. The developed loader was a semi-tracked vehicle operated by a hydraulic system, allowing the safe transportation and loading of cabbage in a steep field. The maximum loading weight of the loader was 1.0 ton. By using two sets of safety devices attached to the loader to avoid the roll-over in a steep field, the static rollover slopes were increased up to 34.0% and 37.4% fur the left and the rear direction, respectively The maximum field speed was about 6km/hr with two cabbage pallets of 750kg at a 25% inclined field. The loading capacity of the loader was about 35 pallets/hr when picking up, carrying, and unloading two cabbage pallets for one loading operation. The loading capacity was more than 8 times in comparison with the conventional human labor. The developed loader could be used fur loading and carrying the other vegetables. The study suggested a possible approach for designing the field machines operated on hillside.