• 산업경영시스템학회지
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• 제42권1호
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• pp.55-63
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• 2019

This paper develops an algorithm to determine the batch size of the batch process in real time for improving production and efficient control of production system with multiple processes and batch processes. It is so important to find the batch size of the batch process, because the variability arising from the batch process in the production system affects the capacity of the production. Specifically, batch size could change system efficiency such as throughput, WIP (Work In Process) in production system, batch formation time and so on. In order to improve the system variability and productivity, real time batch size determined by considering the preparation time and batch formation time according to the number of operation of the batch process. The purpose of the study is to control the WIP by applying CONWIP production system method in the production line and implements an algorithm for a real time batch size decision in a batch process that requires long work preparation time and affects system efficiency. In order to verify the efficiency of the developed algorithm that determine the batch size in a real time, an existed production system with fixed the batch size will be implemented first and determines that batch size in real time considering WIP in queue and average lead time in the current system. To comparing the efficiency of a system with a fixed batch size and a system that determines a batch size in real time, the results are analyzed using three evaluation indexes of lead time, throughput, and average WIP of the queue.

• 산업공학
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• 제24권3호
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• pp.241-247
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• 2011

This paper develops a mathematical model which searches an optimum lot size of a press line, and applies this model to the scheduling of the press line. This mathematical model is not a widely studied cost model but a model which considers the utilization of the press line under a lean production system. In this paper, the optimum lot size is a minimum lot size which does not exceed the total work time of the press line. A production volume and the priority of the production in the press line are adjusted using this optimum lot size. A mathematical model developed in this paper will allow determining the optimum lot size easily in case of variable production environments such as an introduction of a new product and a fluctuation of production volume of each item. Therefore, our model will make a better scheduling of the press line and will enhance the utilization of it.

• 농업과학연구
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• 제29권2호
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• pp.135-148
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• 2002

In recent years, domestic market environment of rice production is confronted with the problems of excessive production and decrease in per capita consumption, resulting in steady decline of domestic rice price. Moreover, as new trade negotiations of WTO or FTA are being forwarded, cheap price of imported rice will also make the rice production environment being worse off. One of the possible production strategies to relieve this situation could be expanding farm size, which increases market competitiveness in terms of cost-saving. Since 1990's, one of the main agricultural policies for rice production in Korea has been expanding farm size. This study aims at 1)exploring brief history of Korean government's agricultural policy for expanding farm size, 2)examining economic effect of farming size expansion, and 3)discussing major role of government to promote appropriate programs for rice-farming and producers. Main conclusion suggests that appropriate farming size should be expanded upto at least five hectares per farm, with producers' effort to reduce farming costs and continuous investments on agricultural infrastructures including irrigation systems, etc. Continuous government's investment on operation and maintenance on water facility is also one of the important factors in expanding farm size.

• 수산경영론집
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• 제43권1호
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• pp.1-9
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• 2012

Based on Clark and Munro's theory of dynamic optimization between fishery resources and production, this study is aimed to take an empirical analysis of optimal production level to the Danish Seine fishery under the sandfish stock rebuilding plan. For empirical analysis, it examined the optimal fish stock size, production and fishing effort levels and it also made an additional evaluation of optimal production changes on main variables by sensitivity analyses. When a 4% of the discount rate is assumed, the optimal sandfish production of Danish Seine fishery would be 3,049 t, and the sandfish optimal stock size is evaluated to be 19,016 t. In addition, the optimal fishing effort is estimated to be 4,368 days. Accordingly, to achieve the optimal production level, current fishing efforts should be reduced while the fish stock size should be increased up to the optimal level.

• 유통과학연구
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• 제14권7호
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• pp.53-61
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• 2016

Purpose - The production efficiency of agricultural crops has been the subject of numerous studies in the field of agricultural economics. This study examines the production efficiency of emerging vineyards in the 14 northern U.S. states and aims to understand raw input and managerial factors affecting the grape production with focusing on the effect of farm size. Research design, data, and methodology - Using a unique survey dataset that was collected from 176 vineyards in 2012, we employed data envelopment analysis (DEA) for estimation of production efficiency in individual vineyards. Production efficiency is regressed on various input and managerial covariates to understand factors influencing the productivity. Results - Although there exists positive correlation between the farm size and productivity of vineyards in Northern U.S. states, we find negative relationship when the farm size is instrumented by the additional farm size expansion indicator. The negative effect is more pronounced for the recently established vineyards. Conclusions - This study suggests that there needs to be adequate managerial improvements for emerging vineyards in northern states for the achievement of increased productivity.

• Journal of Ecology and Environment
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• 제36권3호
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• pp.151-158
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• 2013

We estimated phenotypic selection on the height and number of flowering-stalks in a rosette annual Cardamine hirsuta by applying path analysis to the data collected at three natural populations located in central Japan. The path from rosette size was positively connected with the fruit production through the both height and number of flowering-stalks. In the all three populations, the paths from the number of stalks were more strongly connected with the fruit production than from the height of stalks. The paths from the rosette size showed similar magnitude with the number of stalks and the height of stalks. The direct path from rosette size to the fruit production was detected only at one site. These results suggest stronger phenotypic selection on the rosette size through the number of stalks than the height of stalks. The lateral branching rather than increment of individual inflorescence size is the major response to control the fruit production for C. hirsuta growing in a natural habitat.

• 대한인간공학회지
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• 제3권1호
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• pp.3-11
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• 1984

This study aims to investigate the effects of the size of operator's hand and the use of foot on the production quantity and product quality. To find out the facts the survey is conducted by measuring the hand size for the worker who is randomly chosen and by grouping them into the large hand size group and small hand size group on the base of the measuring data. The grouped operators are assigned to their job as usual, and their daily production quantities and qualities are measured. The survey shows that the production quantity of the small hand group are higher than the large hand group, and the number of defects of the small hand group are less than the large hand group.

• Journal of Ecology and Environment
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• 제44권4호
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• pp.229-240
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• 2020

Background: Genus Quercus is a successful group that has occupied the largest area of forest around the world including South Korea. The acorns are an important food source for both wild animals and humans. Although the reproductive characteristics of this genus are highly variable, it had been rarely studied in South Korea. Therefore, in Seoraksan and Odaesan National Parks (i) we measured the acorn production of Quercus mongolica, an overwhelmingly dominant species in South Korea, for 3 years (2017-2019), (ii) evaluated the spatial-temporal variation of acorn production, and (iii) analyzed the effects of oak- and site-related variables on the acorn production. Results: The annual acorn production of Q. mongolica increased 36 times from 1.2 g m-2 in 2017 to 43.2 g m-2 in 2018, and decreased to 16.7 g m-2 in 2019, resulting in an annual coefficient of variation of 104%. The coefficient of spatial variation was high and reached a maximum of 142%, and the tree size was the greatest influencing factor. That is, with an increase in tree size, acorn production increased significantly (2018 F = 16.3, p < 0.001; 2019 F = 8.2, p < 0.01). Elevation and slope also significantly affected the production in 2019. However, since elevation and tree size showed a positive correlation (r = 0.517, p < 0.001), the increase in acorn production with increasing elevation was possibly due to the effect of tree size. The acorn production of Odaesan for 3 years was 2.2 times greater than that of Seoraksan. This was presumed that there are more distribution of thick oak trees and more favorable site conditions such as deep soil A-layer depth, high organic matter, and slower slopes. Conclusion: As reported for other species of the genus Quercus, the acorn production of Q. mongolica showed large spatial and annual variations. The temporal variability was presumed to be a weather-influenced masting, while the spatial variability was mainly caused by oak tree size.

• Journal of Plant Biotechnology
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• 제6권4호
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• pp.265-268
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• 2004

Cell growth and ginseng saponin production by large-scale suspension (bioreactor) cultures of Panax ginseng were investigated under various inoculum sizes. Cell growth was low at an inoculum size of 40 g FW/L, and the maximum cell growth was obtained with increasing inoculum size up to 100 g FW/L. The cell density of 333 g FW/L and 12.7 g DW/L was obtained at inoculum size of 100 g FW/L after 30 days of cultivation. Maximum saponin production of $4.40\;\cal{mg/g}$ DW was achieved at 60 g FW/L of inoculum size. Thus, inoculum size 60 g FW/L was suitable for optimum biomass accumulation as well as saponin production during bioreactor cultivation of ginseng suspension cells.

• 복식
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• 제55권2호
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• pp.116-128
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• 2005

The aim of this study is to understand problems with both fit and sizing system of gloves by analyzing the glove production industries with an emphasis on the sizing system, production measurement system, and general marking situation. Also, to suggest the basic raw materials for improving sizing system for gloves, actual glove control sizes were compared to the anthropometric data of the previous study Fifteen domestic production companies were participated in this study-Domestic glove production companies established their own sizing system by copying inter-national brand's glove sizing system or by their experience. The Korean Standard of gloves and the 1997 Korean Standard Anthropometrics Measurement for producing glove patterns are not considered because of its discordance with the reality of the required measurements. Domestic glove production companies used different size designation and labeling system. Size measurement unit also showed difference among the glove production companies. Some companies used 'cm', some used 'mm', some used 'inch' for the measurement unit. In general, companies produced 5 to 4 sizes in one design of glove and the production was the highest in M and L size. In 9 out of 15 companies preferred control size as hand length and hand circumference. For reference size, most of the companies preferred finger circumference, finger length, palm length, hand breadth, crotch height, and hand thickness. Actual glove sizes were compared to the anthropometric data of the previous study. The results indicated that most of the measurements of actual glove sizes were significantly larger than the anthropometric data.