• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.420-425
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• 2010

In the process of warm forging, billet is heated up to $800^{\circ}C$ and located in the upper part of die block impression. The scattered oxidized scale may cause workers burn and shortening of die life sticking to the die block impression. The separating materials sprayed in die block cause harmful dust, harmful mist, fume, and bad odor which contaminate workshop environment. The process is classified as one of the avoided jobs and make the planned output achievement difficult. Development of an elimination device to clear out the contaminating materials in the workshop and improvement of the unsatisfactory maintenance method to fix the abrasion of die block impression which delays the dead line, cost increases needs to be developed. In this research, I tried to solve the problems caused in warm forging of bronze pipe joint such as the billet heating process, die maintenance, and manufacturing cost through improvement of warming forging manufacturing method and die maintenance method and eliminating harmful gas which will make the workshop more environment friendly.

• Journal of Labour Economics
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• v.26 no.2
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• pp.31-59
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• 2003

This paper analyzes a social insurance system that integrates unemployment insurance with a pension program, allowing workers to borrow against their future wage income to finance consumption during an unemployment episode and thus improving their search incentives while reducing risks. This paper identifies the conditions under which the integration improves welfare and the factors which determine the optimal degree of integration. A fully integrated system is one in which no reliance is placed at all on a separate tax-funded unemployment insurance program. We show that when the duration of unemployment is very short compared to the period of employment or retirement, the optimal system involves an exclusive reliance on pension-funded self-insurance. This system imposes a negligible risk burden for workers while avoiding attenuating search incentives. We also argue that a joint integration of several social insurance programs with a pension program through an individual account is desirable unless the risks are perfectly correlated to each other.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.5
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• pp.747-752
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• 2011

We conducted a study to select a suitable natural antioxidant from tocopherol, rosemary extract, and green tea extract to be added to commercially-available palm oil to extend the shelf life of non-dairy cream. The green tea extract (400 ppm added) was the most effective of the 3 antioxidants added to the palm oil, increasing OSI time by a factor of 2.3. By examining the correlation coefficients among parameters for storage period, the sensory score indicated that the non-dairy cream was suitable. The shelf life of the TE (green tea extract, 400 ppm) and TEA (TE plus 0.002% ascorbic acid) oils was extended to 24% and 51% more than that of the control at $25^{\circ}C$, respectively. At $20^{\circ}C$, the shelf life of the TE oil was 2.5 months and that of the TEA oil was 5.5 months, increases of 28% and 62.5%, respectively, over the control.

• Journal of the Korea Convergence Society
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• v.10 no.3
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• pp.265-274
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• 2019

The purpose of this study was to explore high school teachers' subjective perception on performance-based pay system(PBPS) for teachers using Q-methodology. This study found three types of high school teachers' subjective perception on the system. Type I is named 'the type of negative perception.' The subjects of type I emphasize the PBPS is not appropriate system for motivating teachers' educational behaviors. Type II is named 'the type of neutral perception.' The subjects of type II emphasize the PBPS is a fair job evaluation, strengthening cooperative atmosphere of educational community but the system is not an usefulness for causing educational behavior etc. Type III is named 'the type of acceptive perception.' The subjects of type III emphasize the PBPS is a good policy to reward for the work most people avoid getting into and improve culture of teaching job etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.1
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• pp.31-35
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• 2003

Switch box is metal box and used for electric wire pipe in building. In manufacturing switch box, we need 5∼6 press machines, 5∼6 dies, 1 tapping machine. and 7∼8 operators. What matters is rise of manufacturing cost and operators' reluctance of working. To solve this problem, we modified the pre-existing die and developed handling mechanism, which leads to improve the manufacturing process. After the research and development, we could reduce the number of machines and workers needed in the process; 2 press machines, 2 dies, 1 tapping machine, and 1 operator. That means we can save labor and the number of operators needed, reduce manufacturing cost, and get the effect of import replacement.

• Korean journal of applied entomology
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• v.62 no.3
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• pp.193-205
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• 2023

Botanical insecticides derived from plant extracts exhibit repellent, antifeedant and enzyme-inhibiting activities against insect pests. Among such pests, phytophagous mites are major threats to horticultural crops. Botanical extracts derived from neem, chrysanthemum, and shrubby sophora are employed as field acaricides. These botanical extracts have low toxicities against natural enemies of the insect pests and, thus, are valuable in pest management. This review focuses on the potential for botanical extracts in the controls of mites, with comparisons of the spectrum of activity, the lethal dose and times and their mode of action. This information will enable better formulation of botanical extracts in integrated mite control.

• Korean Security Journal
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• no.47
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• pp.37-59
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• 2016

The purpose of this study is to investigate about security service history during the 1st and 2nd Republic. The 3rd Republic, one of the important periods, deserves special emphasis until now. But Compared with 1st and 2nd Republic, the 3rd Republic is inferior. Although security service history excluded the 1st and 2nd Republic. This research focused on the two points about the chief of the presidential security and the law of presidential security special order. Firstly, the chiefs of the presidential security in 1st Republic were Kim, Jang-Heung Seo, Jung-Hak Kim, Kuk-Jin Kwak, Young-Joo. Secondly, The law of presidential security special order be specified in Korean presidential security for the first time. Before the 1st Republic already recognized the importance of security services when they adopted the first security service regulations on December 29, 1949, which comprised 25 articles. But this law was only focused on presidential security and promulgated the law more than 10 years ago than law of the office of the Presidential Security in 1963. Deplorable in this law was declared by statute on July 7, 1953 from the 1st Republic, but repealed in 1960 after the 2nd Republic. Thirdly, 2nd Republic established the presidential security organization with the new government has been formed. In spite of this organization can not be kept for a long time, 2nd Republic attempted to professional forms of presidential security organization. The research of secret service history must continue to advance for academical learning.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.4
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• pp.373-377
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• 1997

The bird repellent, methiocarb 50% WP, has been used to reduce the bird damage in the crop field in the European countries. The bird damage occaisonally would occur in the wet direct seeded rice and in soybean field, and resulted in decreasing the crop productivity by the reduction of seedling emergence rate. In this experiment, rice seeds, Hwasungbyeo(Oryza sativa), were coated with the different application rate of methiocarb, 5, 10 and 15 per kg seed, and soybean, Taegwangkong(Glycine max), 2.5, 5.0 and 7.5g. In rice, the seeds coated with 10 and 15g of methiocarb were not lost by bird, while those with 5g and control were lost to 37 and 50% of total seeds, respectively. No damage by birds was observed in rice seedling when the coleoptile and radicle of rice were emerged at 7 days after the water seeding. The crop injury of methiocarb reducing the emergence rate of seedlings, shortening the shoot length, and decreasing the leaf number was occurred at the treated of methiocarb 15g per kg seed. In soybean, the loss of the sprouting by birds was lower in the treatment of methiocarb 7.5g per kg seed than that in both the control and the treatments of methiocarb, 2.5 and 5.0g per kg seed. No crop injury by the treatment of methiocarb was observed in all application rate.

• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.9-19
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• 2001

This study was carried out to investigate natural insectifuge materials from tree extractives in order to substitute for organic synthetic insecticides for food wrapping corrugated board. Tree samples were collected, extracted, fractionated with hexane, $CH_2Cl_2$, ethylacetate(EtOAc) and $H_2O$, and then freezed dried for further study. EtOAc or $H_2O$ fractions were chromatographed on a Sephadex LH-20 column for isolation and purification, and the isolated compounds were characterized by spectroscopic tools such as NMR and MS. Crude extractives of EtOAc and $H_2O$ fractions were added to the printing ink for corrugated board with the concentration of 2% or 3% based on the weight of the ink, then the prepared ink was printed on the corrugated board to be used for evasion test using larva of indian meal moth(Plodia interpunctella(Hubner)). Robtin, dihydrorobinetin and leucorobinetinidin were isolated from the wood extractives of black locust(Robinia pseudoacacia) and the bark of poplar(Populus alba $\times$ glandulosa) contained many kinds of compounds such as (+)-catechin, naringenin, aromadendrin, eriodictyol, sakuranetin and its glycoside, taxifolin, neosaturanin, salireposide, p-coumaric acid and aesculin. Much of (+)-catechin was isolated from the bark extractives of willow(Salix koreensis) in addition to (+)-gallocatechin and p-coumaric acid and the bark of weeping willow(Salix babylonica) also contained (+)-catechin, (+)-gallocatechin, dihydromyricetin and myricetin.

• Korean Journal of Environmental Biology
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• v.25 no.3
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• pp.223-227
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• 2007

Crop loss and damage by wildlife are becoming more serious to residents inside and around National Parks of Korea annually. It could be caused by small size of Parks, which is couples of ten $km^2$ only, and more than a third of total parks' areas are belonging to privates. Wild boar (Sus scrofa) is one of the most harmful pests in nationwide. Treading down crop field using as bedding or resting site are major damaged types and foraging behavior is following. Besides of boars, Korean water deer (Hydropotes inermis), racoon dog (Nyctereutes procyonoides), and badger (Meles meles) are another serious pests. Mainly, farm products planted in upland, such as corns, sweet potatoes, cabbages, etc. are harmed easily, a rate reaches up to 76.9% of whole losses. 92.4% (n=187) of interviewees, who are mostly seniors, cultivate small crop fields smaller than 1 ha. Crop damage would be started from June to late November, time differences are happened due to latitude, climate condition, and crop differences of National Parks. Dusting animal repellents are easier and widespread methods to prevent animal foraging to crop fields and installing noisy makers using gun powder and setting up scarecrows are traditional methods for repelling animals. Nevertheless, effects of these self-defence are turned out to be useful soon after labors done only. Since legal compensation for crop damages by wildlife are not prepared systematically so far, crop loss are rarely reported to local government by most farmers. Systematic and objective methods for quantifying of crop loss by wildlife and population managements system should be offered urgently to well-managed animals habitat and residents' living inside National Parks.