• 한국항행학회논문지
• /
• 제16권5호
• /
• pp.846-852
• /
• 2012

영상분할 결과는 알고리즘에 관련된 매개변수들에 따라 다르기 때문에 최적 분할을 위하여 시행 착오법이 많이 이용된다. 본 논문에서는 3차원 변량 분석법을 이용하여 영역기반 active contour 방법에 관련된 최적 매개변수들을 결정하는 방법을 제안한다. 3원 변량 분석법에 의해서 추출된 결과와 사용자가 영상에서 직접 그린 결과가 상호 비교된다. 마지막으로 각 매개변수들의 주요 효과와 상호작용 효과를 측정하고 최적 값을 추출하기 위하여 점 추정 및 구간 추정 값을 계산한다. 본 논문에서 제안한 방법은 구간 상수 모델을 대상으로 영상분할시 최적 매개변수들을 추출하는데 큰 도움을 줄 것이다.

• 산업경영시스템학회지
• /
• 제38권3호
• /
• pp.117-126
• /
• 2015

This paper is to analyze an integrated production and inventory model in a single-vendor multi-buyer supply chain. The vendor is defined as the manufacturer and the buyers as the retailers. The product that the manufacturer produces is supplied to the retailers with constant periodic time interval. The production rate of the manufacturer is constant for the time. The demand of the retailers is constant for the time. The cycle time of the vendor is defined as the elapsed time from the start of the production to the start of the next production, while the cycle times of the buyer as the elapsed time between the adjacent supply times from the vendor to the buyer. The cycle times of the vendor and the buyers that minimizes the total cost in a supply chain are analyzed. The cost factors are the production setup cost and the inventory holding cost of the manufacturer, the ordering cost and the inventory holding cost of the retailers. The cycle time of the vendor is investigated through the cycle time that satisfies economic production quantity with the production setup cost and the inventory holding cost of the manufacturer. An integrated production and inventory model is formulated, and an algorithm is developed. An numerical example is presented to explain the algorithm. The solution of the algorithm for the numerical examples is compared with that of genetic algorithm. Numerical example shows that the vendor and the buyers can save cost by integrated decision making.

• Industrial Engineering and Management Systems
• /
• 제12권1호
• /
• pp.23-29
• /
• 2013

This paper presents inventory models for fresh agriculture products with time-varying deterioration rate. Due to the particularity of fresh agriculture products, the demand rate is a function that depends on sale price and freshness. The deterioration rate increases with time and is assumed to be a time-varying function. In the models, the inventory cycle may be constant or variable. The optimal solutions of models are discussed for different freshness and the deterioration rate. The results of experiments show that the profit depends on the freshness and deterioration rate of products. With the increasing inventory cycle, the sale price and profit increase at first and then start decreasing. Furthermore, when the inventory cycle is variable, the total profit is a binary function of the sale price and inventory cycle. There exist unique sale price and inventory cycle such that the profit is optimal. The results also show that the optimal sale price and inventory cycle depend on the freshness and the deterioration rate of fresh agriculture products.

• 대한토목학회논문집
• /
• 제32권6B호
• /
• pp.399-406
• /
• 2012

본 연구의 목적은 폐기물매립지에서의 온실가스 발생량 예측모델 및 모델에 적용된 변수들의 산정방법을 개발하는 것이다. 본 연구에서는 온실가스 발생예측 모델 중 1차 반응모델의 변수인 메탄잠재발생량과 메탄발생속도상수를 평가하기 위하여 수정 Gompertz 식과 Logistic 식을 미분한 2개의 식을 적용하였다. 변수들은 실제 폐기물매립지에서의 매립가스 발생량에 대한 실측값과 예측값과의 통계학적 비교를 통해 산정하였다. 매립가스 발생량에 대한 실측값과 수정 Gompertz 식 및 Logistic 식을 미분하여 나타낸 2개의 식을 이용한 매립가스 발생량 예측값에 대한 회귀분석결과 결정계수는 각각 0.92와 0.94로 나타나, 폐기물매립지에서의 매립가스 발생량에 대한 측정값이 있을 경우 회귀분석을 통해 변수를 산정할 수 있는 것으로 나타났다. 또한 실측값이 없는 폐기물매립지에서의 온실가스 발생량을 예측할 수 있도록 하기 위하여 수정 Gompertz 식과 Logistic 식을 미분한 2개의 식을 기초로 하여 예측모델을 개발하였으며, 이 모델들의 정확성을 평가하기 위하여 Qcs(실측값):Q(예측값)의 비에 대한 빈도분포를 평가한 결과 LandGEM 모델보다 높은 정확성을 나타내었다. 따라서 본 연구에서 개발한 모델들은 폐기물매립지에서의 온실가스 발생량 예측에 적합한 것으로 사료된다.

• Archives of Pharmacal Research
• /
• 제20권5호
• /
• pp.480-485
• /
• 1997

The absorption profile of phenytoin Na emulsion were examined compared to that of phenytoin suspension after oral administration in the rat. The corn oil-in-water emulsion, particle size of $184{\pm}$57.8 nm, was prepared using a microfludizer, and phenytoin Na added by shaft homogenizer. The phenytoin emulsion or suspension, 100 mg/kg, were intubated intragastrically using oral dosing needle and blood samples were withdrawn via an indwelling cannula from the conscious rat. Plasma concentrations of phenytoin were measured with HPLC using phenacetin as an internal standard. The plasma concentration versus time data were fitted to a one compartment open model and the pharmacokinetic parameters were calculated using the computer program, Boomer. The phenytoin plasma concentrations from the emulsion at each observed time were about 1.5-2 times higher than those from the suspension, significantly at time of 5, 6 and 7 hr after administration. The absorption $(k_a)$ and elimination rate constant $(k_e)$ were not altered significantly, however the AUC increased from 65.6 to $106.7{\mu}ghr/ml$ after phenytoin suspension or emulsion oral administration, respectively. From an equilibrium dialysis study, the diffusion rate constant $(k_{IE})$ was considerably higher from the phenytoin Na emulsion $(0.0439 hr{-1})$ than phenytoin suspension $(0.0014 hr{-1})$.

• 한국농공학회논문집
• /
• 제52권2호
• /
• pp.1-9
• /
• 2010

This study was carried out to comparison of coefficient of consolidation and the prediction of excess pore water pressure in agricultural reservoir on soft clay ground. For the purpose of verification of the proposed equation, laboratory model tests and field tests were performed and excess pore water pressure was compared to those predicted with the Terzaghi's method. The predicted excess pore water pressure according to ponding was very applicable to practice because it was close to the observed data. Also, for the comparison of coefficient of consolidation, the oedometer, constant rate of strain (CRS), and Rowe cell tests were performed. The coefficient of consolidation at the Rowe cell and CRS tests showed a greate increase than in the oedometer test. The ratio of the vertical and horizontal coefficient of consolidation showed a large difference according to various tests method and mixing ratio. Therefore, it is recommended that careful attention should be paid to predicting the required consolidation period in agricultural reservoir.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제10권S_4호
• /
• pp.157-164
• /
• 2001

The performance of fluidized-bed reactor with Photomedia, immobilized TiO$_2$ onto the porous ceramic ball using a sol-gel method has been studied in this work. A simple model substrate, dilute Rhodamine B (RhB), was decolorized at room temperature. For the purpose of comparison, the slurry reactor and the Inner Wall Coated Reactor (IWCR) were used. The aim of this work was to develop the photocatalytic fluidized bed reactor (PFBR) through contrasting the photodegradability of various reactors such as the TiO$_2$slurry reactor, the inner-wall coated reactor (IWCR). In this study, the RhB was decolorized in three types of reactor. Even though the reaction rate constant of PFBR was lower than that of slurry reactor, PFBR had the advantages of preventing the wash-out of photocatalyst, so it can be operated continuously.

• 한국식품저장유통학회지
• /
• 제24권4호
• /
• pp.505-509
• /
• 2017

Water vapor adsorption kinetics of vacuum-dried jujube powder were investigated in temperature and relative humidity ranges of 10 to $40^{\circ}C$ and 32 to 75%, respectively. Water vapor was initially adsorbed rapidly and then reached equilibrium condition slowly. Reaction rate constant for water vapor adsorption of vacuum-dried jujube powder increased with an increase in temperature. The temperature dependency of water activity followed the Clausius-Clapeyron equation. The net isosteric heat of sorption increased with an increase in water activity. Good straight lines were obtained with plotting of $1/(m-m_0)$ vs. 1/t. It was found that water vapor adsorption kinetics of vacuum-dried jujube powder was accurately described by a simple empirical model, and temperature dependency of the reaction rate constant followed the Arrhenius-type equation. The activation energy ranged from 50.90 to 56.00 kJ/mol depending on relative humidity. Arrhenius kinetic parameters ($E_a$ and $k_0$) for water vapor adsorption by vacuum-dried jujube powder showed an effect between the parameters with the isokinetic temperature of 302.51 K. The information on water vapor adsorption kinetics of vacuum-dried jujube powder can be used to establish the optimum condition for storage and processing of jujube.

• 대한전자공학회논문지TE
• /
• 제39권2호
• /
• pp.17-28
• /
• 2002

최근 신경회로망 구조 또는 퍼지논리를 이용한 자력등화 즉, 비선형 등화에 대한 연구가 활발하게 진행되고 있다. 본 논문에서는 계산의 복잡성과 등화 성능 사이에 더 나은 trade-off를 찾기 위해 스텝 크기(step size)를 자동적으로 조절할 수 있는 즉, 에러 오차 값이 크면 계수갱신율을 크게 하고 에러 오차 값이 작으면 계수갱신율을 작게 하여 빠른 수렴비와 낮은 초과 MSE를 갖는 TS(Tagaki-Sugeno) 퍼지 모델과 ISI에 강하고 위상변화에 둔감한 CMA(Constant Modulus Algorithm)를 접목시킨 새로운 FSG (Fuzzy Stochastic Gradient)/CMA 알고리즘을 제안하였다. 제안된 FSG/CMA 알고리즘을 사용한 채널 적응 등화기를 설계하여 모의실험한 결과 기존 알고리즘 보다 3.5dB의 SNR이 개선됨을 확인하였다.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제15권2호
• /
• pp.90-100
• /
• 2015

Reliability growth rate (or reliability growth curve slope) have the two cases of trend as a constant or changing one during the reliability growth testing. The changing case is very common situation. The reasons of reliability growth rate changing are that the failures to follow the NHPP (None-Homogeneous Poisson Process), and the solutions implemented during test to break out other problems or not to take out all of the root cause permanently. If the changing were big, the "Goodness of Fit (GOF)" of reliability growth curve to test data would be very low and then reduce the accuracy of assessing result with test data. In this research, we are using Duane model and AMSAA model for assessing test data and projecting the reliability level of complex and repairable system as like construction equipment and vehicle. In case of no changing in reliability growth rate, it is reasonable for reliability engineer to implement the original Duane model (1964) and Crow-AMSAA model (1975) for the assessment and projection activity. However, in case of reliability growth rate changing, it is necessary to find the method to increase the "GOF" of reliability growth curves to test data. To increase GOF of reliability growth curves, it is necessary to find the proper parameter calculation method of interesting reliability growth models that are applicable to the situation of reliability growth rate changing. Since the Duane and AMSAA models have a characteristic to get more strong influence from the initial test (or failure) data than the latest one, the both models have a limitation to contain the latest test data information that is more important and better to assess test data in view of accuracy, especially when the reliability growth rate changing. The main objective of this research is to find the parameter calculation method to reflect the latest test data in the case of reliability growth rate changing. According to my experience in vehicle and construction equipment developments over 18 years, over the 90% in the total development cases are with such changing during the developing test. The objective of this research was to develop the newly assessing method and the process for GOF level increasing in case of reliability growth rate changing that would contribute to achieve more accurate assessing and projecting result. We also developed the new evaluation method for GOF that are applicable to the both models as Duane and AMSAA, so it is possible to compare it between models and check the effectiveness of new parameter calculation methods in any interesting situation. These research results can reduce the decision error for development process and business control with the accurately assessing and projecting result.