• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.133-138
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• 2019

BACKGROUND: Production function gives the equation that shows the relationship between the quantities of productive factors used and the amount of product obtained, and can answer a variety of questions. This study was carried out to evaluate the relationship between irrigation water used for rice production and rice productivity by the production function which shows the mathematical relation between input and output. METHODS AND RESULTS: The statistical data on rice production and on the amount of irrigation water were used for the production function analysis. The analysis period was separated for 1966-1981 and 1982-2011, based on goal's change on agriculture from 'increasing food' to 'complex farming'. The relation between irrigation and yield considering production function is a short-term production function both before and after 1982. These results can be expressed by the sigmoid relation. When comparing the graphs of the two analyzed periods, there are differences in quantity between the maximum point and the minimum point during the same analysis period, which can be called an 'Irrigation Effect' by the difference of irrigation, and 'Technical Effect' by the difference by inputs like as fertilizers etc. CONCLUSION: The results could be useful as information for assessing the relationship between agricultural water and the productivity of rice and predicting rice productivity by irrigation water in Korea.

• Korean Journal of Human Ecology
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• v.8 no.1
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• pp.95-107
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• 1999

Difficulties in the measuring home food production activities obstructs development of home production activity related studies. For solving such problems, this study intended to develope a home food production frequency scale. The data were collected from 219 housewives in Taejon. Validity, reliability, correlation, and multiple regression analysis were used to test home food production frequency scale. The scale's validity and reliability were reveled considerable potential for its use to ascertain relationships between home food production activity and other family variables.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.3
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• pp.71-79
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• 1993

Dynamic production planning problems are to determine the optimal production times and production quantities of product for discrete finite periods. In previous many researches, the solutions for these problems have been developed through the algorithms using dynamic programming. The purpose of this research is to suggest the new algorithm using linear programming. This research is to determine optimal production quantities of product in each period to satisfy dynamic for discrete finite periods, minimizing the total of production cost and inventory holding cost. Cost functions are concave, and no backlogging for product is allowed. The new algorithm for capacity constrained problem is developed.

• Journal of the Korea Society for Simulation
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• v.12 no.1
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• pp.35-48
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• 2003

This paper suggests the long-term strategy of the production distribution planning considering the capacity of factory production and the uncertain demand in a supply chain. This paper determines the near optimal capacity of factory production by using the advantages of mathematical and simulation models. Also, the relationship between the capacity from the suggested model and the strategy of production and distribution in a supply chain is studied. Arena is used for modeling and analysis.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.36
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• pp.93-103
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• 1995

This paper des with an economic production quantity model with partial backorders for the situation in which production lead time is deterministic and demand during lead time follows a continuous distribution. In the model, an objective function is formulated In minimize an average annual inventory cost. And then the procedure of iterative solution method for the model is developed to find both production reorder point and production quantity. Finally, sensitivity analysis for various partial backorder ratios and standard deviations of demand during production lead time are presented.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.1
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• pp.52-58
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• 2014

This study consists of two parts. The first discusses the development of a single production forming machine which was reported in earlier papers. The second outlines the development of a multi-production forming machine, which consists primarily of a film feeding unit, an unwinding unit, and a heating block unit. The heating block unit of the multi-production forming machine has 30 members per die. An analysis of the stress deformation and temperature deviation of this machine is carried out using ANSYS Workbench and CFX-11 under the design conditions. According to this analysis, the maximum deflection in the Z-direction is $0.05104{\mu}m$ and the maximum temperature deviation is $0.7^{\circ}C$ when the temperature of the heating block unit is $175^{\circ}C$. It was also found that these values are structurally safe. The advantage of the developed multi-production forming machine is demonstrated to be in its offering of a proper voice test.

• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.481-495
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• 2016

Lily, which is one of Korea's main flower exports, is one of the most important agricultural product in the country. Korean lily farmers have difficulty earning more profit from producing lilies, because of the high cost of lily bulbs. Most lily bulbs used in Korea are imported from the Netherlands. Thus, the Korean government has kept trying to supply more and better Korean lily bulbs. However, many experts have questioned the efficiency and economic value of the Korean lily production system. The purpose of this paper is to analyze the economic value of the production of lily bulbs in Korea. Especially, this study evaluates the economic value of the production systems of Korean lily bulbs and compares the results from several cases. The results of the present study presents some useful findings, as follows: first, two Korean production areas (Gangneung and Jeju) show a positive economic value but one Korean production area (Taean) presents problems causing a negative economic value. Second, the Korean production area in Vietnam currently has trouble in the view of economic value but will likely overcome that problem. Third, the production area in the Netherlands shows the best economic value. Thus, Korean lily bulb producers need to benchmark that system.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.344-352
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• 2019

Marine production strings are continuously affected by unstable internal fluid during operation. In this paper, the structural governing equation for marine production string self-induced vibration is constructed. A finite element analysis model is established based on Euler-Bernoulli theory and solved by the Newmark method. Furthermore, based on reliability theory, a self-design procedure is developed to determine the operability envelope for marine production string self-induced vibration. Case studies show: the response frequency of the production strings is consistent with the excitation frequency under harmonic fluctuation and mainly determined by the first-order natural frequency under stochastic fluctuation. The operability envelope for marine production string self-induced vibration is a near symmetrical trapezium. With the increasing of natural gas output, the permissible fluctuation coefficient dramatically decreases. A reasonable centralizer spacing, increasing top tension, and controlling natural gas output are of great significance to the risk control in marine production string operation.

• Journal of Korea Trade
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• v.23 no.2
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• pp.14-33
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• 2019

Purpose - This paper aims to articulate determinants of inter-organizational cooperation based on to the extent to which inter-organizational tasks are related to product development and production processes. Design/Methodology - This research conducted OLS regression analysis based on the data acquired from questionnaire survey in Korean auto industry. Findings - Our analysis has verified that complementary and compatible resources, as well as physical and human asset specificities, positively affect inter-organizational product development cooperation. Conversely, in the production process, only complementary resources positively affect inter-organizational cooperation, whereas compatible resources and physical asset specificity have a negative influence. The changing characteristics of compatible resources (with IT innovations and AI), and physical asset specificity (influenced by a rising need to reduce production costs), cause inter-organizational cooperation in production to decrease. Originality/value - This research attempts to expound upon these determining factors of inter-organizational cooperation by considering both complementary-compatible resources and asset specificity in product development and production simultaneously. The reason why the impact of complementary-compatible resources and asset specificity on inter-organizational cooperation is critical in understanding the determinants of inter-organizational cooperation is that the attributes of complementary-compatible resources and asset specificity in production have changed drastically due to the continuing diffusion of IT innovations and AI (Artificial Intelligence).

• Transactions of Materials Processing
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• v.19 no.8
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• pp.523-528
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• 2010

The forging industry is composed of those plants that make parts to order for customers; or make parts for their own company's internal use; or make standard parts for resale. Also, the forging industry is closely related with automobile industry and ship building industry - Korea's major export industry. But, it is hard to find the Korea's forging industry's statistical analysis because it is not revealed with final product. In this paper, we perform statistical analysis using the micro data service provided by the Statistics Korea. We focus on the analysis of production costs as well as the status of forging company and their employee.