• Journal of the Korean Operations Research and Management Science Society
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• v.1 no.1
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• pp.151-170
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• 1976

There are many cases of production processes which intermittently produce several different kinds of products for stock through one set of physical facility. In this case, an important question is what size of production run should be prduced once we do set-up for a product in order to minimize the total cost, that is, the sum of the set-up, carrying, and stock-out costs. This problem is used to be called scheduling of multiple products through a single facility in the production management field. Despite the very common occurrence of this type of production process, no one has yet devised a method for determining the optimal production schedule. The purpose of this study is to develop quantitative analytical models which can be used practically and give us rational production schedules. The study is to show improved models with application to a can-manufacturing plant. In this thesis the economic production quantity (EPQ) model was used as a basic model to develop quantitative analytical models for this scheduling problem and two cases, one with stock-out cost, the other without stock-out cost, were taken into consideration. The first analytical model was developed for the scheduling of products through a single facility. In this model we calculate No, the optimal number of production runs per year, minimizing the total annual cost above all. Next we calculate No$_{i}$ is significantly different from No, some manipulation of the schedule can be made by trial and error in order to try to fit the product into the basic (No schedule either more or less frequently as dictated by) No$_{i}$, But this trial and error schedule is thought of inefficient. The second analytical model was developed by reinterpretation by reinterpretation of the calculating process of the economic production quantity model. In this model we obtained two relationships, one of which is the relationship between optimal number of set-ups for the ith item and optimal total number of set-ups, the other is the relationship between optimal average inventory investment for the ith item and optimal total average inventory investment. From these relationships we can determine how much average inventory investment per year would be required if a rational policy based on m No set-ups per year for m products were followed and, alternatively, how many set-ups per year would be required if a rational policy were followed which required an established total average inventory inventory investment. We also learned the relationship between the number of set-ups and the average inventory investment takes the form of a hyperbola. But, there is no reason to say that the first analytical model is superior to the second analytical model. It can be said that the first model is useful for a basic production schedule. On the other hand, the second model is efficient to get an improved production schedule, in a sense of reducing the total cost. Another merit of the second model is that, unlike the first model where we have to know all the inventory costs for each product, we can obtain an improved production schedule with unknown inventory costs. The application of these quantitative analytical models to PoHang can-manufacturing plants shows this point.int.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.1
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• pp.15-19
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• 1989

This experiment was carried out in order to know the changes in dry matter production of the 2nd cutting by the times of established pasture and its relation with morphological and structural characters of orchardgrass sward. Experimental pasture was established by the times of year, from 1 year to 7 year, 1986 through 1980, alternately. The results were summarizedas follows: 1. The population density of the 2nd cutting was extremely decreased by the times of established year. 2. The dry weight of $plantsW)$ was positively significant correlations with plant length(PL), number of tillers per plant (NT/pl.) and the dry weight of plant(DW/pl.). 3. The highest value of the dry weight of plants(DW) was obtained at 7 year old pasture. 4. The pasture productivity of 7 year old pasture was resulted by the increases of regrowth capacity, yield components and structural characters of the 2nd cutting. 5 . Relationship between morphological and structural characters concerned vegetational structure of the 2nd cutting were changeable year by year.

• Food Science and Industry
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• v.51 no.1
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• pp.45-60
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• 2018

The starch industry in Korea had been based on sweet potato and potato for long time to produce starches which were used for mainly starch noodle such as cellophane noodle. Because of the poor storage stability, high price, and fluctuation of production by year and year of potatoes, the raw material for the production of starch had been changed to corn in 1970s. Along with this, the mass production system had been established, which enabled the production of various starch-related products including modified starches for food, textile, paper, and other industrial uses, starch sweetners, high fructose corn syrup, and gelatinized starch. In this paper, a brief background of corn industry in Korea has been described. The production of starch from corn has been emphasized and the future of corn industry in relation with GMO has been suggested.

• 한국산학경영학회:학술대회논문집
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• 2006.06a
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• pp.171-190
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• 2006

Toyota 2005 annual report said Toyota has six consecutive fiscal year positive revenues and record breaking revenues during recent four consecutive years. Net profit is 11% grower than last year. (\11,000,000,000,000). In the spotlight they have record breaking net profit every year, their strongest point is their unique production system which come up with MUDA(waste) free and ongoing improvement activity. Their basic production philosophy is value added through improve production efficiency which can be possible by eliminating MUDA(waste). This basic philosophy's key points are "Just in Time" and "Automation with human". Recently, Korean manufacturing companies and service companies have a growing interest in Toyota Production System. They try to find ways for appling Toyota system to their companies. Through observing Toyota production theory, understand Toyota Production System, Through studying practical application in industrial fields, examine application possibility for Korean industry and more detailed researches are required.

• Korean Journal of Medicinal Crop Science
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• v.4 no.4
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• pp.271-276
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• 1996

This studies were conducted to basic information on growth characteristics and root yield in progeny the derived from different bolting years and to establish optimum seed production time in Angelica gigas. Plant height of early and mid-growing stages had decreased with each year increase in bolting year, but showed no significance in late growing stage at different bolting years. Root charac­teristics including root length, root diameter and dry root weight was slightly good and it had high root/ shoot ratio in third year seed production. respectively. Bolting rate showed that first year seed 38.1%, second year seed 10.4% and third year seed 1.2%, respectively. Therefore, optimum seed production time revealed third year seed for reduce bolting rate. Root yield at different bolting years showed average 1,690kg per hectare as fresh root weight on first year seed, 2,860kg on second year and 2,940kg on third year seed, respectively. A significant positive correlation was appeared between bolting rate and plant height in mid-growing stage. On the other hard, there was highly significant negative correlation between bolting rate and root yield.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.4
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• pp.264-270
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• 1994

This experiment was undertaken to determine the effect of pasture ages on the total production and seasonal yield trends, botanical composition and forage quality of pasture mixtures. This experiment was conducted at the Livestock Experiment Station, RDA, Suweon. The results obtained were as follows : 1. Total dry matterDM) yield of pasture mixtures was the highest in the first year, and thereafter no significant reduction in the 2nd through the 4th year, but decreased by 30% in the 5th year. 2. The 34.4% of total DM yield was produced at the first cut, and decreased from then on. Total DM yield of pasture mixtures varied by year and climatic facton. In 1992, Total DM and TDN yields of pasture mixtures were 13.4 and 8.5 IvlT/ha, respectively. 3. The content of crude protein(CP), in virro DM digestibility(IVDMD) and TDN of pasture mixtures were 12-14, 70-80, and 62-65%, respectively. The highest forage quality was obtained at the 4th cutting. 4. The botanical compositions of legumes and weeds were increased as the year of establishment advanced, and highly increased at the 3rd cut after summer growth. 5. Based on the results of this study it appears that economic forage production could be expended to the 4th year with proper management, and the special renovation techniques may be needed for maintenance of pasture yield from the 5th year.

• Journal of Korea Foresty Energy
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• v.18 no.1
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• pp.6-10
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• 1999

This study was conducted to examine biomass production and its allocation characteristics by the planting density for 12- year - old Pinus densiflora forma erecta Uyeki plantation located in Chilbo Experimental Forest of Seoul National University in Suwon, Kyonggj-do. Different sample trees were selected for harvest by the planting density as follows; six trees from 1.0m X 1.0m, five trees from 1.8m X 1.8m, four trees from 3.0m X 3.0m. Stem, previous year branches, current year branches, previous year needles and current year needles were weighed respectively with the stratified clipping method, and biomass production and its allocation characteristics were analyzed : (1) Total biomass of the above-ground was the highest at the planting density of 1.8m X l.8m and followed by 1.0m X l.0m. (2) The higher the planting density was, the lower the ratio of biomass in branches and needles. (3) As the planting density decreased, the moisture contents of stem and current year branches increased but those of needles and previous year branches decreased. (4) Maximum photosynthetic layer appeared in the upper portion of the tree at higher density plantation.

• Journal of Korean Society of Forest Science
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• v.55 no.1
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• pp.30-36
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• 1982

Wood biomass production at 1-year, 2-year, and 3-year rotations on both low and upper hills at 2m 2m spacing (25,000 trees/ha) was studied for a six-year period with following 12 species; Lespedeza cyrtobotrya Amorpha fruticosa. Robinia pseudoacacia, Acer saccharinum, Platanus orientalis Populus alba ${\times}$ P. glandulosa $F_1$, Salix alba, Pinus rigida, Alnus hirsuta var. sibirica, A. inokumai A. gultinosa, and A. incana. In One-year rotation, Lespedeza cyrtobotrya produced largest amoung of biomass (2.6 t/ha/year, fresh weight) and Populus alba ${\times}$ P. glandulosa $F_1$ the second largest (2.2 t/ha/year) on low hill. In two-year rotation, the latter produced the largest amount (4.8 t/ha/year) and Alnus hirsuta var. sibirica second largest (2.8 t/ha/year) on low hill. In three-year rotation, the largest weight (11.2 t/ha/year) was produced by Robinia pseudoacacia and the second largest (6.2 t/ha/year) by Alnus hirsuta var. sibirica on low hill Amorpha fruticosa, Acer saccharinum, Platanus orientalis and Salix alba were not suitable for biomass or fuelwood productio due to poor growth. Biomass yield on upper hill was reduced considerably for all tewlve species, with less than 4 t/year at maximum Only nitrogen fixing species (Robinia and Alnus species) are recommended on upper hill for biomass production wood sprouting ability of species was generally associated with good biomass production. Calori values of ovendry wood ranged from 4,485 cal/g for Salix alba to 5,125 cal/g for Alnus glutinosa. For maximum biomass production a three-year ratation with coppice is preferred to one-year and two-year roataions The best species appeared to be Robinia pseudoacacia and Alnus hirsuta var sibirica.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.245-249
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• 1976

The present paper deals with estimation of zooplankton production in the South Sea of Korea based on the plankton data of the Annual Report of Oceanographic Observations, Fisheries Research and Development Agency, Korea during the period of seven years from 1967 through 1973. Net zooplankton biomass of the layer tipper 150 meters is calculated with an average of $70.2\;mg/m^3$ and gross production in the region $59,800\;km^2$ are about $5.14\~10.27\times10^6\;tons/year$. Mean zooplankton productivity is estimated $86\~172\;tons/km^2/year$.

• Journal of Embryo Transfer
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• v.33 no.4
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• pp.265-270
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• 2018

Up-to-date artificial insemination (AI) using frozen sperm consider as the most widely using technology for improvement of Korean Native Cow (Hanwoo) embryo production. However, it is time consuming, required at least 15~20 years to make more than 6 generations, and their offspring number is limited. To overcome such limitations, superovulation and in vitro fertilization have been developed. For superovulation, the number of produced embryos are not enough for commercialization and donor cows need rest period. This led to use of slaughterhouse ovary for in vitro fertilization, but it is impossible to repeat the collection from the same individual and it only can improve the genetic merits of offspring for one generation. Production of embryos using Ovum Pick-Up (OPU) technique, where oocytes can be repeatedly collected from living elite donor, might overcome these limitations. In this study, we investigated the possibility of using OPU technique from donors at different age and different session periods for mass-embryo-production. Oocytes were collected from 26 donor cows twice per week, 3 - 4 months per year, between 2013 and 2016. Results showed that, the average number of embryo produced in first year used donor was significantly higher than that in second year used donor ($3.89{\pm}2.85$ vs $3.29{\pm}2.70$), however, there was no significant difference between third year used donor ($3.51{\pm}3.32$) and other groups. Taken together, our data showed that repeated using of donor up to three years is possible for in vitro embryo mass-production. Moreover, OPU can be used as suitable embryo producing technique for livestock breed improvement.