• 한국해안해양공학회지
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• 제12권1호
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• pp.19-26
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• 2000

폭풍발생에 따른 해안종단방향의 표시이동은 경빈과 사구의 침식, 연안사주의 생성등 해안단면변화에 있어 주요한 요인의 하나로 알려져 있다. 그러나 폭풍발생에 따른 표사이동은 표사의 입경, 수면상승높이, 쇄파고 등 많은 요소들에 의해 복합적으로 작용하기 때문에 현재에도 정확한 예측이 어려운 실정이다. 본 논문에서는 해안단면에서의 평형에너지소산개념과 표사량 예측에 있어 주요한 요소인 표사량 파라미터를 차원해석을 통하여 변수화하고 수치모델에 도입하여 폭풍발생에 따른 해안종단방향의 해안단면변화와 해빈침식에 대하여 분석하여 보았다. 해안종단방향의 해빈침식은 단면형상 파라미터, 표사량 파라미터, 수면상승높이에 의해 크게 영향을 받음을 알 수 있다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.172-175
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• 2009

The purpose of this study is to predict the forming limit diagram (FLD) of strain-rate sensitive materials on the basis of the Marciniak and Kuczynski (M-K) theory. The strain-rate effect is taken into consideration in such a way that the stress-strain curves for various strain-rates are inputted into the formulation as point data, not as curve-fitted models such as power function. To solve the nonlinear system of equations derived from the equilibrium and constraints in the groove region and the safe zone, the Newton-Raphson method is used. The theoretical FLDs using four different yield criteria, that are von Mises, Hill (1948), Hill (1979), Logan and Hosford, are compared with the experimental, numerical (FEA) and other theoretical results. A new trial is made where a modified M-K model having n-step grooves is introduced to describe a real localized neck.

• Journal of applied mathematics & informatics
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• 제9권1호
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• pp.101-124
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• 2002

The convergence rate of a numerical procedure barred on Schwarz Alternating Method (SAM) for solving elliptic boundary value problems (BVP's) depends on the selection of the interface conditions applied on the interior boundaries of the overlapping subdomains. It hee been observed that the Robin condition(mixed interface condition), controlled by a parameter, can optimize SAM's convergence rate. Since the convergence rate is very sensitive to the parameter, Tang[17] suggested another interface condition called over-determined interface condition. Based on the over-determined interface condition, we formulate the two-layer multi-parameterized SAM. For the SAM and the one-dimensional elliptic model BVP's, we determine analytically the optimal values of the parameters. For the two-dimensional elliptic BVP's , we also formulate the two-layer multi-parameterized SAM and suggest a choice of multi-parameter to produce good convergence rate .

• 한국대기환경학회지
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• 제5권1호
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• pp.1-10
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• 1989

The sensitivity analysis is a method to quantify to what extent the output of a model changes with the values of input parameters. This will lead to increase model accuracy through measurement validation. Three line source air quality models, HIWAY 2, PAL, and CALINE 3 were selected for this study. The input parameters analysed included wind speed, wind direction, stability, emission rate, mixing height, receptor distance, initial dispersion coefficient, surface roughness, and averaging time. It turned out that PAL model generally showed higher concentration than other two models, and that between CALINE 3 and HIWAY 2, CALINE 3 showed higher concentration than HIWAY 2 model near the line sources, but beyond a certain downwind distances HIWAY 2 model showed higher concentration. The modesl were very sensitive to wind speed especially in the range of 0 $\sim$ 1 m/s and to wind direction near the parallel wind to streets. In case of emission rate, the output concentration was directly proportional to these input parameters. And the sensitivity of the input parameters such as stability, mixing height, initial dispersion coefficient, surface roughness, and averaging time were not very significant.

• Journal of Preventive Medicine and Public Health
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• 제20권1호
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• pp.40-48
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• 1987

In this paper strategic planning is applied for effective management to improve hospital income. Though community hospital has been set up for improving the health status of community, it must be trying to increase income for continuing with referral hospital in the community. The most useful tool of management to do this purpose is thought of strategic planning. Therefore this paper developed strategic planning a typical community hospital, which for it presenting the strategic planning process and developing the simulation model for evaluation of strategic alternatives. In the result it is represented that admission rate is the most sensitive to hospital operating income among the important variables in the model. And simulation by changing the parameter could estimate the yearly hospital income in the response of alternatives. This strategic planning simulation model has had constraints as number of date but also significance such as evaluating the alternatives by quantitative model and at first applying the hospital in our country.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1989년도 봄 학술발표회 논문집
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• pp.38-43
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• 1989

하중 재하속도의 영향을 고려한 철근 콘크리트 부재의 거동을 예측하기 위한 해석모델이 layer modeling 기법에 의하여 개발되었다. 철근 콘크리트 부재의 압축 및 휨거동 해석 과정에서 하중에 따른 변형율 속도를 변수로 사용한 개발된 모델을 이용하여 얻은 해석결과는 여러가지 다른 하중재하 속도하에서 실험된 실험결과와 비교되었으며, 그의 비교결과는 만족스러웠다. 본 연구에서는 개발된 모델을 사용하여 철관 콘크리트 보 및 기둥에서 다양하게 사용될 수 있는 기하학적 형태 및 사용재료 등의 변수변환이 하중재하 속도에 따른 부재의 강도 및 강성에의 민감성을 조사하였다. 본 논문에서는 또한 하중재하 속도의 영향을 고려할 수 있는 철근 콘크리트 단면의 휨 및 압축강도를 계산할 수 있는 두개의 설계 공식도 제안하였다.

• 수산경영론집
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• 제29권2호
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• pp.199-216
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• 1998

An economic appraisal of a proposed marine ranching project is analysed using capital budgeting model such as net present value(NPV) and internal rate of return( IRR) as well as sensitivity analysis and goal seeking model. Of the factors for economic appraisal, direct benefits are to be determined by estimated harvest, prices and costs incurred by catching fishes, and indirect benefits include the additional economic effect of recreational fishing. And judging the worth of these project options depends upon the choice of discount rate of which 8.5% is recommended here. On the basis of estimated production, prices and costs the project is expected to yield NPV=615 million won and IRR=8.8%, which is quite accepted for an economic feasibility, under the first scenario, and NPV= -127 million won and IRR=7.93%, which is rejected, under the second scenario. Sensitivity analysis has been performed by calculating the switching value and sensitivity indicator in respect of the main project parameters. The results suggest that the project NPV and IRR are especially sensitive to fishes(rock fish and other rock fish) prices and fixed costs. Finally goal seeking analysis is carried out in order to reach a desired level of performance like NPV=0 in respect of the amount of hatchery-reared juverniles, the prices and the discount rate.

• 한국지하수토양환경학회지:지하수토양환경
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• 제11권2호
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• pp.45-55
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• 2006

강변여과수 취수 방식의 도입이 고려되었던 경상북도 고령군 낙동강변의 충적대수층을 대상으로 2차원 지하수 유동모사를 수행하여, 취수정 및 주변 대수층에서의 지하수위와 하천수 유입량의 계절적 변화를 분석하였다. 개념모델의 하천 경계조건은 연평균 하천수위를 고정 수두로 설정하는 경우와 실제 관측된 시계열 자료를 이용하여 변동 수두로 설정하는 경우로 구분하여 모사를 수행하였다. 모사 결과 산정된 하천수 유입 비율은 고정하천수두 모사의 경우 연중 $74.3{\sim}87.0%$의 범위를 보이며 연평균 82.4%인 반면, 변동하천수두 모사의 경우 $52.7{\sim}98.1%$, 연평균 78.5%로 나타났다. 따라서 시기별로 변동하는 하천수위가 하천수 유입 비율에 큰 영향을 미치며, 하천수 유입 비율을 정확하게 산정하기 위해서는 변동하천수두 조건을 이용해야 하는 것으로 해석된다. 강변으로부터 취수정까지의 이격거리를 변화시키면서 모사를 반복 수행한 결과 취수정 이격거리가 커질수록 하천수 혼합 비율은 다소 감소하지만 그 영향이 수 % 정도로 매우 작게 나타났다. 강변여과 취수 시 지하수위 및 하천수 혼합비율에 영향을 미치는 인자인 대수층의 수리전도도 및 저유계수, 지하수 함양량, 취수량 등에 대한 민감도 분석을 수행하였다. 대수층의 평균 지하수위와 하천수 유입 비율은 취수량과 지하수 함양량 변화에 민감한 반면, 취수정의 지하수위는 수리전도도와 취수량에 민감한 것으로 나타났다.

• Archives of Pharmacal Research
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• 제27권7호
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• pp.763-768
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• 2004

To investigate the feasibility of developing a new quercetin transdermal system, a preformulation study was carried out. Therefore, the effects of vehicles and pressure-sensitive adhesives (PSA) on the in vitro permeation of quercetin across dorsal hairless mouse skin were studied. Among vehicles used, propylene glycol monocaprylate (PGMC) and propylene glycol mono-laurate were found to have relatively high permeation flux from solution formulation (i.e., the permeation fluxes were 17.25$\pm$1.96 and 9.60$\pm$3.87 $\mu\textrm{g}$/$\textrm{cm}^2$/h, respectively). The release rate from PSA formulations followed a matrix-controlled diffusion model and was mainly affected by the amount of PSA and drug loaded. The overall permeation fluxes from PSA formulations were less than 0.30 $\mu\textrm{g}$/$\textrm{cm}^2$/h, which were significantly lower compared to those obtained from solution formulations. The lower permeation fluxes may be due to the decrease of solubility and diffusivity of quercetin in the PSA layer, considering the fact that the highest flux of 0.26 $\mu\textrm{g}$/$\textrm{cm}^2$/h was obtained with the addition of 0.2％ butylated hydroxyanisole in PGMC-diethyl-ene glycol monoethyl ether co-solvents (80-85 ： 15-20, v/v). Taken together, these observations indicate that improvement in the solubility and diffusivity of quercetin is necessary to realize fully the clinically applicable transdermal delivery system for the drug.

• East Asian Economic Review
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• 제19권1호
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• pp.3-38
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• 2015

Fama's (1984) volatility relations show that the risk premium in foreign exchange markets is more volatile than, and is negatively correlated with the expected rate of depreciation. This paper studies these relations from the perspective of goods markets frictions. Using a sticky-price general equilibrium model, we show that near-random walk behaviors of both exchange rates and consumption, in response to monetary shocks, can be derived endogenously. Based on this approach, the paper provides quantitative results on Fama's volatility relations.