• 자원환경지질
• /
• 제42권2호
• /
• pp.133-141
• /
• 2009

본 연구는 지질자원 연구개발 분야에서 경제적 효과 분석 연구가 활발히 수행되지 않은 분야인 지하수자원 분야의 연구개발 사업을 대상으로 경제적 효과를 분석하고자 한다. 제주도 청정 대용량 지하수 개발사업 중 2004년에서 2007년 기간에는 5년간 44.70억원(2006년 가치, 5.5% 할인율 적용)의 연구개발비용을 지출하여 제주도 지하수 부존량 산정, 대용량 지하수 개발 가능 지역 선정 및 개발 타당성 제시 등의 연구가 실시되었다. 본 사업의 편익요소로 대용량(2만톤/일 이상) 지하수 부존지역 깨소 설정으로 3,600만톤/년의 제주도 지하수 개발지역을 확보한 것으로 보았다. 이에 지하수개발시업의 편익에 연구개발 기여도(9.97%)를 적용, 연구개발투자에 대한 경제성 분석을 실시하였다. 기존의 경제이론 및 결과자료(가상가치평가, 생산기석도)와 시장자료(수입단가, 시설용량)를 기초로 한 지하수개발사업의 편익을 도출하고, 사업의 실행화 시점 및 할인율의 변동에 따른 영향을 제시하였다. 분석 결과 상수도 및 병입수 상업화로 연간 총 1,223만톤의 지하수 이용은 2,934억원의 가치로 나타났으며, 연구개발 투자효과는 2006년 순현재가치(NPV)로 30년간 총 136.59억원, 비용대편익비율(B/C ratio)은 4.06이며 내부수익율(IRR)은 22.74%로 나타났다. 사업화 시행 시점을 기존 10년 후에서 5년 후로 앞당기는 경우 추가적인 55.80억원의 편익이 산정되며, 사업의 할인율이 1% 상승하는 경우 역시 166.73억원 편익이 발생하여, 순편익 121.82억원, 비용편익비 3.71로 연구개발사업 타당성을 확보한다.

• Structural Engineering and Mechanics
• /
• 제48권1호
• /
• pp.17-39
• /
• 2013

In the present paper, a coaxial rotating smeared crack model is proposed for mass concrete in three-dimensional space. The model is capable of applying both the constant and variable shear transfer coefficients in the cracking process. The model considers an advanced yield function for concrete failure under both static and dynamic loadings and calculates cracking or crushing of concrete taking into account the fracture energy effects. The model was utilized on Koyna Dam using finite element technique. Dam-water and dam-foundation interactions were considered in dynamic analysis. The behavior of dam was studied for different shear transfer coefficients considering/neglecting fracture energy effects. The results were extracted at crest displacement and crack profile within the dam body. The results show the importance of both shear transfer coefficient and the fracture energy in seismic analysis of concrete dams under high hydrostatic pressure.

• Korea-Australia Rheology Journal
• /
• 제20권2호
• /
• pp.51-58
• /
• 2008

This paper describes a two-step Tikhonov regularization procedure for converting the steady shear data generated by parallel-disk viscometers, in the presence of wall slip, into a shear stress-shear rate function and a wall shear stress-slip velocity functions. If the material under test has a yield stress or a critical wall shear stress below which no slip is observed the method will also provide an estimate of these stresses. Amplification of measurement noise is kept under control by the introduction of two separate regularization parameters and Generalized Cross Validation is used to guide the selection of these parameters. The performance of this procedure is demonstrated by applying it to the parallel disk data of an oil-in-water emulsion, of a foam and of a mayonnaise.

• 수산경영론집
• /
• 제47권4호
• /
• pp.1-13
• /
• 2016

Fish mortality is the most important success factor in aquaculture management. To analyze the effect of mortality considering biological and economic condition is a important problem in land-based aquaculture. This study is aimed to analyze the effect of mortality for duration of cultivation in land-based aquaculture. This study builds the mathematical model that finds the value of decision variable to minimize cost that sums up the water pool usage cost, sorting cost, fingerling cost and feeding cost under critical standing corp constraint. The proposed mathematical model involves many aspects, both biological and economical: (1) number of fingerlings (2) timing and number of batch splitting event, based on (3) fish growth rate, (4) mortality, and (5) several farming expense. Numerical simulation model presented here in. The objective of numerical simulation is to provide for decision makers to analyse and comprehend the proposed model. When extensive biological and cost data become available, the proposed model can be widely applied to yield more accurate results.

• 대한조선학회지
• /
• 제24권1호
• /
• pp.1-8
• /
• 1987

It is shown that irregular frequencies in the source and doublet distribution method, can be eliminated if the Green function associated with Kelvin's source of pulsating strength, is modified only in the region inside the body at the level of the undisturbed free surface. The system of the resulting Green integral equation is augmented without loss of the square-integrable property of its kernel so hat the discretisation yield N linearly independent equations for N unknown variables. From the solution, the potential and velocity at any point on the wetted surface of a surface-piercing body can be found using the properties of the double layer composed of the source and normal doublet distribution.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2005년도 국제학술회의
• /
• pp.100-113
• /
• 2005

Leaf color and plant vigor are key indicators of crop health. These visual plant attributes are frequently used by greenhouse managers, producers, and consultants to make water, nutrient, and disease management decisions. Remote sensing techniques can quickly quantify soil and plant attributes, but it requires humans to translate such data into meaningful information. Over time, scientists have used reflectance data from individual wavebands to develop a series of indices that attempt to quantify things like soil organic matter content, leaf chlorophyll concentration, leaf area index, vegetative cover, amount of living biomass, and grain yield. The recent introduction of active sensors that function independent of natural light has greatly expanded the capabilities of scientists and managers to obtain useful information. Characteristics and limitations of active sensors need to be understood to optimize their use for making improved management decisions. Pot experiments involving sand culture were conducted in 2003 and 2004 in a green house to evaluate corn and red pepper biomass. The rNDVI, gNDVI and aNDVI by ground-based remote sensors were used for evaluation of corn and red pepper biomass. The result obtained from the case study was shown that ground remote sensing as a non-destructive real-time assessment of plant nitrogen status was thought to be a useful tool for in season crop nitrogen management providing both spatial and temporal information.

• 수산경영론집
• /
• 제42권2호
• /
• pp.85-96
• /
• 2011

Oliver flounder population density affect Oliver flounder growth and mortality rate. In laboratory pilot experiment, Oliver flounder growth rate is inversely proportional to stocking density. But previous study has not proved external validity. This study is aimed to analyze the effect of stocking density on the Oliver flounder culture farms in Jeju Island. In order to do this, I selected 13 farms in Jeju island as a sample. In the study, various analytical methods including productivity analysis, regression analysis, statistical analysis were conducted for 13 Oliver flounder culture farms. The result of analysis can be summarized as follows. First, in case of the Oliver flounder culture farms, Bertalanffy equation is not applicable to the Oliver flounder growth. Second, the Oliver flounder stocking density, defined as the surface area of Oliver flounder per $m^2$ of water surface area, is preferred to density definition defined as the weight of Oliver flounder per $m^2$ of water surface area on the Oliver Flounder Culture Farms case. Third, growth rate and production weight on the Oliver flounder culture farms are inversely proportional to stocking density on spearman rank correlation test. When extensive comparable biological and culture condition data become available, analysis model can be easily modified to yield more accurate results.

• 한국가시화정보학회지
• /
• 제19권2호
• /
• pp.15-25
• /
• 2021

Numerical studies on the hydrodynamics of a freely falling rigid sphere in bounded and unbounded water domains are presented having investigation on the drag coefficient, normalized velocity, surface pressure and skin friction coefficient as a function of time. Two different conditions of the bounded and unbounded domains have been simulated by setting the blockage ratio. Four cases of bounded domains (B.R. = 1%, 25%, 45%, 55%, 65% and 75%) have been taken, whereas the unbounded domain has been considered with 0.01%. In the case of the bounded domain (higher values of B.R.), a substantial reduction in normalized velocity and increase in the drag coefficient have been found in presence of the bounded domain. Moreover, bounded domains also yield a significant increase in the pressure coefficient when the sphere is partially submerged, but the insignificant effect is found on the skin friction coefficient. In the case of the unbounded domain, a significant reduction in normalized velocity occurs with a decrease in Reynolds number (Re) and also increase in the drag coefficient.

• 한국응용과학기술학회지
• /
• 제40권6호
• /
• pp.1363-1372
• /
• 2023

This study is concerned with the optimization of the manufacturing process of a hot water extract containing antioxidant activity from Lycium barbarum, traditionally known to have various physiological activities. For the establishment of the optimization process, the central composite design of response surface methodology(RSM) was used. Thirteen extraction processes were performed by encoding the independent variables, extraction temperature (65.9℃-94.1℃) and extraction time (2.59 hr-5.41 hr). As a result of the experiment, the optimal manufacturing conditions for the extract were 340.0 mg/100 g of GAE at an extraction temperature of 94.1℃ and an extraction time of 5 hr. The maximum yield of flavonoids was 22.44 mg/100 g of HES at an extraction temperature of 94.1℃ and an extraction time of 4 hr. The conditions for producing the extract with the maximum antioxidant capacity (DPPH 92.12%) were 90℃ and 4.5 hr extraction time. Therefore, the optimal manufacturing process conditions for extracts containing total phenol content, flavonoid content, and DPPH radical scavenging activity, which are dependent variables, were extraction temperature of 90-95℃ and extraction time of 4 hr, which were not significantly different from the actual values. Therefore, Lycium barbarum extract rich in total phenol and flavonoid content related to antioxidant function is expected to be used as a functional food and cosmetic material.

• 한국산림과학회지
• /
• 제98권3호
• /
• pp.247-254
• /
• 2009

이 연구에서는 산림과학원 광릉시험림을 사례연구 대상으로 산림기능에 따른 목표임상 조건이 산림경영에 미치는 영향을 알아보기 위하여 선형계획법을 적용하였다. 이를 위해 대상산림의 사회 경제 생태적 요구에 따라 자연환경림, 자원생산림, 수원함양림 그리고 경관보존림으로 구성된 4개의 산림기능으로 구분하고, 각 기능에 적합한 산림시업체계표를 작성하였다. 선형계획수식모형은 Model II 기법을 적용하여 구성하였으며, 재적생산의 극대화를 목적함수로 그리고 비감소수확, 벌채허용면적, 계획기간말의 영급구조 및 수종선택 등의 경영방침을 제약조건에 포함시켰다. 선형계획수식모형을 이용하여 각 경영시나리오별로 최적해를 계산하고 재적생산량, 순현재가 그리고 영급구조 등을 비교하여 목표임상 조건이 산림경영에 미치는 영향을 알아보았다.