• 한국재난정보학회 논문집
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• 제14권3호
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• pp.262-270
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• 2018

연구목적: 본 연구는 국내와 국외의 도시 및 고속철도터널 유지관리 계측센서의 손망실 현황을 조사하고 분석을 실시하였다. 연구방법: 도시철도터널 유지관리 계측센서 설치 후 5년에서 6년의 손망실율은 서울 지하철5,6,7,9호선은 14.2%에서 14.8%, 영국의 Channel tunnel은 13.9%로 거의 유사하게 나타나 5년 경과연수에서는 15%로 설정하는 것이 타당한 것으로 판단된다. 연구결과: 고속철도터널 유지관리 계측센서 설치 후 3년에서 5년의 손망실율은 호남고속 철도1단계 에서 60.9%로 서울지하철5,6,7,9호선의 4배 이상 크게 나타났다. 결론: 8년에서 10년의 경부고속철도2단계에서는 66.8%로 나타나 5년에서 10년 사이에 급격하게 증가하므로 향후 10년 이상 장기간의 경과연수에 따른 계측항목별 손망실율 연구가 필요할 것으로 판단된다.

• 한국유체기계학회 논문집
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• 제14권1호
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• pp.48-54
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• 2011

The effect of channel cutback on three-dimensional flow fields and aerodynamic losses downstream of a cavity squealer tip has been investigated in a turbine rotor cascade for the squealer rim height-to-chord ratio and tip gap height-to-chord ratio of $h_{st}/c$ = 5.51% and h/c = 2.0% respectively. The cutback length-to-camber ratio is changed to be $CB/c_c$ = 0.0, 0.1, 0.2 and 0.3. The results show that longer cutback delivers not only stronger secondary flow but also higher aerodynamic loss in the tip leakage vortex region, meanwhile it leads to lower aerodynamic loss in the passage vortex region. The discharge of cavity fluid through the cutback opening provides a beneficial effect in the reduction of aerodynamic loss, whereas there also exists a side effect of aerodynamic loss increase due to local wider tip gap near the trailing edge. With increasing $CB/c_c$ from 0.0 to 0.3, the aerodynamic loss coefficient mass-averaged all over the measurement plane tends to increase slightly.

• 대한기계학회논문집B
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• 제20권4호
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• pp.1363-1375
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• 1996

Oil-film flow visualizations and three-dimensional flow measurements using a five-hole probe have been conducted to investigate three-dimensional flow characteristics and total pressure losses of a row of film-cooling jets injected in spanwise direction. For several span-to-diameter ratios, experiments are performed in the case of three velocity ratios of 0.5, 1.0 and 1.5. The flow measurements show that downstream flow due to the injection is characterized by a single streamwise vortex instead of a pair of counter-rotating vortices, which appear in the case of streamwise injection, and the vortex strength strongly depends on the velocity ratio. Regardless of the velocity*y ratio, presence of the spanwise film-cooling jets always produces total pressure loss, which is pronounced when the velocity ratio is large. It has also been found that the production of the total pressure loss is closely related to the secondary vortical flow. In addition, effects of the span-to-diameter ratio on the flow and total pressure loss are discussed in detail.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.17-20
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• 2000

TCP is ill-suited to real-time multimedia applications. Its bursty transmission, and abrupt and frequent wide rate fluctuations cause high delay jitters and sudden quality degradation of multimedia applications. Deploying non congestion controlled traffic results in extreme unfairness towards competing TCP traffic. Therefore, they need to be enhanced with congestion control schemes that not only am at reducing loss ratios and improve bandwidth utilization but also are fair towards competing TCP connections. This paper proposes a differentiated rate adaptation algorithm based on loss and round trip time. Rate in a sender quickly responds to loss ratio and holds steady state. Additionally, this algorithm reduces loss ratio by loss prediction in a receiver.

• 한국초전도ㆍ저온공학회논문지
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• 제9권1호
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• pp.72-75
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• 2007

Magnetization loss of HTS wire is strongly dependent on the critical current density and the aspect ration of the HTS wire. This paper presents the magnetization loss of stacked BSCCO wire and stacked YBCO wires which had different critical current densities. Width of the BSCCO wire was 4mm and widths of two YBCO wires were 4mm and 8mm. Single wire, two stacked three stacked and four stacked wires were fabricated and tested. Ratio of magnetization loss of BSCCO wire to YBCO wire was presented at single wire. For stacked wire, ratio of magnetization loss of single wire to stacked wire was presented. Test results shows that magnetization losses of stacked wires were greater than that of single wire at large high magnetic field above critical magnetic field.

• 한국지반환경공학회 논문집
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• 제3권1호
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• pp.67-77
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• 2002

준설토의 체적변화는 여수토를 통해 물과 함께 빠져나간 토립자의 유실량과 침강되어 새로이 형성된 지반 표면에서의 건조수축과 지반 내에서의 자중압밀에 의한 침하량의 합으로 생각할 수 있다. 그러나 현재까지 체적변화요인과 관련하여 자중압밀과 건조수축에 관한 연구에 비해 토립자의 유실과 관련된 연구는 미미한 실정이다. 따라서 본 연구에서는 준설토의 체적변화요인 중 여수토를 통해 외부로 유실되는 토량을 보다 명확히 규명하기 위해, 준설작업을 실시하기 전의 원지반과 준설토를 투기하여 조성된 매립 지역에서 각각 채취한 시료에 대한 입도분석결과에 Marsal의 수정파쇄율(일본토질공학회, 1990)을 적용하여 유실율을 평가하는 방법을 적용하였고, 이를 검증하기 위하여 기존의 방법을 이용하여 평가한 유실율과 비교 검토해 보았다. 또한 실내모형시험을 실시하여 현장계측 결과와 비교 검토하였으며 마지막으로 준설토를 단계투기법에 의하여 투기했을때 유실율에 미치는 영향을 실내모형시험을 통하여 확인하였다.

• 한국농공학회논문집
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• 제50권1호
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• pp.13-21
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• 2008

Water losses in irrigation canals are mainly estimated as the sum of conveyance and delivery water loss. The losses occur via the evaporation, infiltration, gate operation and water distribution processing. Recently, the study regarding these water losses are not satisfactory enough, also delivery water loss has not been mainly considered on field design. The objective of this study is to investigate and analyze the volume of water loss in irrigation canals considering condition of actual farm land. A field measurement was performed at four research sites, which are managed by Korea Rural Community & Agriculture Corporation, to evaluate conveyance and delivery water loss for 2 years. The measurement was performed by canal type, size and designed flow using the inflow-outflow method at a major points such as start and end of each canal, derivation point of canal and inlet of paddy fields. Results of this study showed that water loss ratio in lateral canals was bigger than that of main canal unlike current design standard and the loss decrease as flow increase. The total of water loss ratio including conveyance and delivery water loss in several irrigation canals ranged between 33.25 and 45.0%.

• 한국응용과학기술학회지
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• 제11권2호
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• pp.139-146
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• 1994

MDABM and MDAEW, as a accelerating weight loss agents, were prepared by adding water to myristyldimethylbenzylammonium bromide(MDAB) and myristyldimethylethylammonium ethyl sulfate (MDAE) synthesized. As a result of weight loss finishing of the MDABW and MDAEW with NaOH on PET fiber, the ratio of weight loss of MDABW was very larger than that of MDAEW. This result showed that quaternary ammonium bromide had higher weight loss effect than quaternary ammonium sulfate, and the ratio of weight loss was greatly varied with the kind of quaternary ammonium salts used. In these conditions, proper treatment concentration, treatment time, and treatment bath ratio were about 8g/l, $6O{\sim}90min$, and $40:1{\sim}50:1$, respectively.

• Geomechanics and Engineering
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• 제37권6호
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• pp.565-576
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• 2024

In this study, the earthquake risk assessment of single-story RC precast buildings in Turkey was carried out using loss curves. In this regard, Kocaeli, a seismically active city in the Marmara region, and this building class, which is preferred intensively, were considered. Quality and period parameters were defined based on structural and geometric properties. Depending on these parameters, nine main sub-classes were defined to represent the building stock in the region. First, considering the mean fragility curves and four different central damage ratio models, vulnerability curves for each sub-class were computed as a function of spectral acceleration. Then, probabilistic seismic hazard analyses were performed for stiff and soft soil conditions for different earthquake probabilities of exceedance in 50 years. In the last step, 90 loss curves were derived based on vulnerability and hazard results. Within the scope of the study, the comparative parametric evaluations for three different earthquake intensity levels showed that the structural damage ratio values for nine sub-classes changed significantly. In addition, the quality parameter was found to be more effective on a structure's damage state than the period parameter. It is evident that since loss curves allow direct loss ratio calculation for any hazard level without needing seismic hazard and damage analysis, they are considered essential tools in rapid earthquake risk estimation and mitigation initiatives.

• 한국임상보건과학회지
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• 제3권1호
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• pp.276-289
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• 2015

Purpose. To efficiently manage hospitals, this study aims to analyze the general characteristics, common-type balance sheet, common-type profit and loss statement and financial ratio of a tertiary general hospital and use the results as basic data for future hospital development by comprehending causes for problems and analyzing hospital management. Methods. By using information about a tertiary general hospital, located in A Metropolitan City, provided through Alio (www.alio.go.kr), a public organization information provider, Health Insurance Review & Assessment Service, and Ministry of Health and Welfare, this study used data during 3 years(2011 to 2013) by analyzing the general characteristics, common-type balance sheet, common-type profit and loss statement, industrial mean ratio and financial ratio of hospitals. Results. This study came to the following conclusions through the general characteristics, common-type balance sheet, common-type profit and loss statement, industrial mean ratio, financial ratio, circular chart and ROI by analyzing the data from 2011 to 2013. Conclusions. Overall, A Tertiary General Hospital showed an increase in fixed cost due to the construction of J Hospital and even in the size of capital and assets. It also showed an increase in medical profit, but the increase of its medical cost was higher, resulting in a financial loss. Especially, this hospital showed a slight decrease in net profit, featuring a reduction in inventory turnover. When the management of A Tertiary General Hospital was predicted based on such features, this hospital is expected to improve its profit structure through the opening of J Hospital, and it is necessary for this hospital to increase and sustain the turnover rate of inventories accumulated by managing them better.