• 품질경영학회지
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• 제23권3호
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• pp.20-32
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• 1995

This paper is concerned with the economic selection of both the lower limit and the process mean for a continuous production process. Consider a production process where items are produced continuously. All of the items are subject to acceptance inspection. The items for which the measured values of the quality characteristic are larger than the lower limit are accepted, and those smaller than the lower limit are rejected and excluded from shipment. The process mean may be set higher to reduce the costs incurred by imperfect quality. Using a higher process mean, however, results in a higher production cost when production cost is an increasing function of the quality characteristic. Assuming that the quality characteristic is normally distributed with known variability, cost models are constructed which involve production cost, cost incurred by imperfect quality, rejection cost, and inspection cost. Methods of finding optimal values of the lower limit and the process mean are presented and numerical examples are given.

• Corrosion Science and Technology
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• 제8권4호
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• pp.157-161
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• 2009

The corrosion resistance of reinforcing bar was studied to endure the marine environment during shipment. The red rust on the surface did not damage the adherence in the concrete structures, especially in highly alkaline environment, but made the consumer doubt of the quality. The passivation process by alkalization of the quenching water in the tempcore process failed to endure the long shipping period. The ceramic coating by sol-gel process improved the corrosion resistance without damaging the mechanical properties and adherence between concrete and reinfiorcing bar. Optimal concentration of the coating solution and coating temperature were tested. No additional energy was necessary for the coating process by spraying during cooling process, resulting simplified process and low cost. Salt spray test, cyclic corrosion test and atmospheric test were employed to confirm the resistance. The corrosion rates were presented by rating number and polarization resistance. The coating layer was examined by FIB, XRD and SEM etc.

• 수산경영론집
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• 제47권4호
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• pp.65-75
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• 2016

The purpose of this study was to analyze the production and marketing control effects of aqua-cultured flounder required for stable income growth of aqua-cultured household. We analyzed the supply and demand structure of cultured flounder using the partial equilibrium model approach. And we estimated the optimal yield of cultured flounder and analyzed the effect of marketing control through constructed model. The main results of this study are summarized as follows. First, the fitness and predictive power of the estimated model showed that the RMSPE and MAPE values were less than 5% and Theil's inequality coefficient was very close to 0 rather than 1. It was evaluated that the prediction ability of the aqua-cultured flounder supply and demand model by dynamic simulation was excellent. Second, dynamic simulation based on policy simulation was conducted to analyze the price increase effect of production and shipment control of cultured flounder. As a result, if the annual production volume is reduced by 1%, 5%, and 10% among 32,852~37,520 tons, it is analyzed that the price increase effect is from 1.2% to 12.5%. Finally, this study suggests that the production and marketing control can increase the price of aqua-cultured flounder in the market. In this paper, we propose a policy implementation of the total supply system instead of conclusions.

• Industrial Engineering and Management Systems
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• 제14권1호
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• pp.1-10
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• 2015

In this paper, we consider multi-item inventory management. When managing a multi-item inventory, we coordinate replenishment orders of items supplied by the same supplier. The associated problem is called the joint replenishment problem (JRP). One often-used approach to the JRP is to apply a can-order policy. Under a can-order policy, some items are re-ordered when their inventory level drops to or below their re-order level, and any other item with an inventory level at or below its can-order level can be included in this order. In the present paper, we propose a method for finding the optimal parameter of a can-order policy, the can-order level, for each item in a lost-sales model. The main objectives in our model are minimizing the number of ordering, inventory, and shortage (i.e., lost-sales) respectively, compared with the conventional JRP, in which the objective is to minimize total cost. In order to solve this multi-objective optimization problem, we apply a genetic algorithm. In a numerical experiment using actual shipment data, we simulate the proposed model and compare the results with those of other methods.

• 산업기술연구
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• 제22권B호
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• pp.89-93
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• 2002

When testing products before shipment to the customer, quality characteristics are measured to decide whether or not their values are between the specification limits. Unfortunately, this testing procedure can lead to incorrect decisions because of gauge error. That is, good products can erroneously be qualified as bad, and bad products as good, and this has consequences for producer's and consumer's risk. In cases of such as this, the compressed gauge limit can be used to achieve the desired product quality level dictated by the manufacturer or the customer. A compressed gauge limit is a limit set by the manufacturer on a test gauge that is tighter than the specification limit established by the customer. The compressed gauge limits should be set at levels to achieve the defect levels desired by the customer and simultaneously minimize the loss of good product that is rejected due to errors in the gauges. In this article, the models for determining the defect levels and the losses obtained by adding compressed gauge limits will be developed. A response surface model approach is utilized which allows an optimal operating condition to be generated relatively easily.

• 한국환경과학회지
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• 제26권11호
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• pp.1247-1253
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• 2017

The Fuji variety of apple, introduced in Japan, has excellent storage quality and good taste, such that it is the most commonly cultivated apple variety in Gunwi County, North Gyeongsang Province, Korean Peninsula. Accurate prediction of harvest maturity allows farmers to more efficiently manage their farm in important aspects such as working time, fruit storage, market shipment, and labor distribution. Temperature is one of the most important factors that determine plant growth, development, and yield. This paper reports on the beta distribution (function) model that can be used to simulate the the phenological response of plants to temperature. The beta function, commonly used as a skewed probability density in statistics, was introduced to estimate apple harvest maturity as a function of temperature in this study. The model parameters were daily maximum temperature, daily optimum temperature, and maximum growth rate. They were estimated from the input data of daily maximum and minimum temperature and apple harvest maturity. The difference in observed and predicted maturity day from 2009 to 2012, with optimal parameters, was from two days earlier to one day later.

• 한국환경과학회지
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• 제24권11호
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• pp.1547-1550
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• 2015

Fuji apple variety introduced in Japan has excellent storage quality and good taste so it is most commonly cultivated in the Korean Peninsula. Accurate prediction of harvest maturity allows farmers to more efficiently manage their farm, such as working time, fruit storage, market shipment and labor distribution so it is very important. This study was carried out to predict the harvest maturity of 'Fuji' apple using DTS (Days Transformed to Standard temperature) model based on the Arrhenius law in the Gunwi province of the South Korea. Input data are daily average temperature and apple harvest maturity. Predicted the harvest maturity of Fuji apple after estimating the optimal parameters by using the Nelder-Mead method. The differences of observed and predicted harvest maturity day are approximately 1 to 4 days and the RMSE is 2.9.

• 농업과학연구
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• 제29권1호
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• pp.24-31
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• 2002

본 연구는 수출용 딸기에 대한 실용적 $CO_2$ 처리방안을 도입하여 수출단계에서 과실 품질에 미치는 영향을 조사하기 위하여 실시하였다. $CO_2$ 처리에 따른 경도 증진 효과는 과숙한 과실에서 더욱 컸으나 과실의 실제적인 경도는 미숙한 과실에서 높아 미숙과에 대한 처리 효과가 실용적인 가치가 있었다. 처리조건은 수확한 과실을 예냉실에 넣어 냉각시키고 15% 이상의 $CO_2$에 4시간 이상 노출시키는 것이 바람직 하였으며 $CO_2$ 처리의 잔류효과는 모의 선적 및 소매과정까지 유지되었다. 그러나 과숙한 과실에서는 소매과정을 부여할 때 과피면이 검붉게 변하여 상품가치를 상실하였다. 본 연구 결과에서 농가 소유의 소형 저온실을 활용하여 간편하게 $CO_2$를 처리할 수 있으므로 수출은 물론 국내 유통에서 품질 증진을 위한 수확 후 처리기술로 활용 가능성이 있었다.

• 한국산업보건학회지
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• 제24권1호
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• pp.59-64
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• 2014

Objectives: The principal aim of this study is to investigate and analyze domestic usage amounts of insecticide in rice cultivation in order to provide fundamental data for establishing a job-exposure matrix(JEM) related to farmers working with agricultural insecticides. Materials and Methods: An investigation of domestic usage amounts of insecticides rice cultivation was performed through two methods. The first method utilized information on agricultural pesticides published annually by the Korea Crop Protection Association(KCPA). The second method made use of area of cultivation of rice as officially determined by Statistics Korea(SK). An estimation of domestic usage of insecticides in rice cultivation through the second method was determined by multiplying the total cultivation area of rice($m^2$) by the optimal spray volume of insecticides for rice cultivation per unit of cultivation area($kg/m^2$). Results: As a result of the analysis of public data regarding insecticides in rice cultivation, it was found that the domestic usage amount has decreased sharply from the first year of market sales(1969) to the final data year(2012). There is little difference in the annual usage trend of insecticides in rice cultivation between shipment and estimation. Also, the annual usage trends of insecticides in rice cultivation based on regional classification were nearly similar to those based on the overall aspect. Conclusions: The region which used the largest volume of insecticide in rice cultivation in Korea was the Jeolla Provinces, followed by the Gyeonsang Provinces, the Chungcheong Provinces, Seoul/Gyeonggi Province, Gangwon Province and Jeju Province. Substantially, the mean ratio of usage amounts of insecticide based on shipments and those based on estimation by cultivation area was $96{\pm}29%$, which indicates that the domestic usage amount of insecticide for rice cultivation corresponded to the optimal spray standard per unit area.

• 한국컴퓨터정보학회논문지
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• 제29권7호
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• pp.33-40
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• 2024

가축의 생체중은 건강 및 사육 환경 관리에 중요한 정보이고 이를 통해 최적 사료량이나 출하 시기 등을 결정하게 된다. 일반적으로 가축의 무게를 측정할 때 체중계를 이용하지만, 체중계를 이용한 가축 무게를 측정하는데 상당한 인력과 시간이 필요하고 성장 단계별 측정이 어려워 사료급이량 조절 등의 효과적인 사육 방법이 적용되지 못하는 단점이 있다. 본 연구는 축산 양돈 분야에 영상 및 이미지 데이터를 수집, 분석, 학습, 예측 등을 통해 포유자돈, 이유자돈, 육성돈, 비육돈 구간별 체중 측정에 관한 연구와 함께 정확도를 높이고자 하였다. 이를 위해 파이토치(pytorch), YOLO(you only look once) 5 모델, 사이킷런(scikit learn) 라이브러리를 사용하여 학습시킨 결과, 실제치(actual)와 예측치(prediction) 그래프에서 RMSE(root mean square error) 0.4%와 MAPE(mean absolute percentage error) 0.2%로 유사한 흐름을 확인할 수 있다. 이는 양돈 분야의 포유자돈, 이유자돈, 육성돈, 비육돈 구간에서 활용할 수 있으며 다각도로 학습된 이미지 및 영상 데이터와 실제 측정된 체중 데이터를 바탕으로 지속적인 정확도 향상이 가능하고 향후 영상판독을 통해 돼지의 부유별 생산량에 대한 예측으로 효율적인 사육관리가 가능할 것으로 기대된다.