• Journal of Korean Society for Quality Management
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• v.47 no.3
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• pp.453-465
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• 2019

Purpose: A main purpose is to increase the operational rate and reduce operating maintenance costs by Improving the durability of Blower of Military Armored Vehicle and Self-propelled Artillery. As a result, it is expected to improve the service quality of customers. Methods: After analyzing the cause of the stop of the blower, the improvement plans were established and the effectiveness of each improvement plans were verified by testing. Results: Mechanical, electrical and environmental factors affecting brush wear were reviewed, but it was difficult to specify the cause, which necessitated a review of the application of the BLDC motor. Conclusion: After applying the BLDC motor to the blower, tests proved that the existing blower can be replaced. It is expected that this study will help improve the durability life of similar equipment that is applied with Brushed DC motors as well as blowers.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.693-702
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• 2021

The aim of this study was to analyze the genetic diversity and distance of the Korean native black goat line. Thus far, this Korean native black goat line has not been studied intensively, especially in genetic diversity and relationship studies in comparison with other breeds. In total, eleven microsatellite (MS) markers were used to evaluate alleles from 391 Korean native black goats and foreign hybrid animals. The genetic diversity index was evaluated based on the allele distributions. Four Korean native black goat lines showed expected ranges of observed heterozygosity, expected heterozygosity, and polymorphism information content (PIC) values for use in genetic diversity research (0.509 - 0.643, 0.434 - 0.623 and 0.356 - 0.567). Lines from the Korean native black goat and foreign hybrid were clearly separated according to principal coordinates analysis (PCoA), phylogenetic tree and tended to be clustered in each Korean native black goat line. Thus, this study can be used for analyzing the genetic relationships between Korean native black goats and foreign breeds for line preservation and for fundamental information to determine breed improvement strategies.

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.165-180
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• 2023

This study investigated 62 nested quadrat plots of Jinaksan to identify community classification and changes of the vegetation by using the phytosocial method and analyzed importance values. Vegetation types were classified into 8 communities: Quercus mongolica community, Q. variableis community, Q. aliena community, Pinus densiflora, Q. acutissima, Zelkova serrata, Carpinis laxiflora, and C. tschonoskii. The significance value was highest in Q. mongolica (62.75) followed by P. densiflora (55.16), Q. variabilis community (25.03), Z. serrata (22.17), Q. aliena (18.30), Prunus serrulata var. pubescens (16.86), C. laxiflora (13.25), Q. acutissima (10.72), C. tschonoskii (10.08), Q. serrata (8.02), Fraxinus sieboldiana (6.93), Acer pseudosieboldianum (6.73), and Styrax obassis (5.73). Quercus mongolica displayed a stable distribution pattern, presenting a reverse J-shaped curve from the diameter at breast height (DBH) analysis, and it was judged that current state would be maintained for a certain period. In addition, P. densiflora is expected to dominate for the time being and Quercus species are expected to gradually decrease.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.4
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• pp.583-588
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• 2016

The high-temperature steam pipes of thermal power plants are subjected to severe conditions such as creep and fatigue due to the power plant frequently being started up and shut down. To prevent critical pipes from serious damage and possible failure, inspection methods such as computational analysis and online piping displacement monitoring have been developed. However, these methods are limited in that they cannot determine the life consumption rate of a critical pipe precisely. Therefore, we set out to develop a life assessment system, based on a three-dimensional piping displacement monitoring system, which is capable of evaluating the life consumption rate of a critical pipe. This system was installed at the "M" thermal power plant in Malaysia, and was shown to operate well in practice. The results of this study are expected to contribute to the increase safety of piping systems by minimizing stress and extending the actual life of critical piping.

• Journal for History of Mathematics
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• v.13 no.2
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• pp.1-12
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• 2000

The first life tables of the Korean, the so-called Chosun Joomin Saengmyong_Pyo were constructed by Misusima, the head professor, and his faculty members of Preventive Medicine Department, Division of Medical Science, Keijo Imperial University in 1937. The above mentioned life tables were based on the age specific mortality rates by the resident registration and the data of a couple of total population censuses conducted by the Governor of Chosun Government General in 1925 and 1930. And they revealed the following facts: (1) by the first Abridged Life Tables of Korean(Chosunin), the expected life span of Korean male and female were 32 and 35 from 1925 to 1930, respectively. (2) the infant mortality rate of Korean male and female were 252- and 230-person among 1000-born respectively. In conclusion, nobody knows the level of those Life Tables, but it is important in terms of that they are the origin of Korean life tables.

• 연구논문집
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• s.33
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• pp.67-79
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• 2003

The life of oilless bearing affects the durability of scroll compressor. The main shaft of the scroll compressor is supported by oiiless bearing. Some of the major parameters which influence the life of oilless bearing are rotational speed, normal load, environment of refrigerant and oil film thickness. The reliability evaluation of oiiless bearing is performed through the acceleration life test for reduction of experimental time and costs. In this study, the experimental and computational investigations were performed to verify the effects of various parameters on the life of oilless bearing. The acceleration factor was achieved with the lubrication analysis between the scroll compressor and the developed reliability tester. the expected life of oilless bearing was guaranteed by reliability evaluation accompanied with the acceleration life test.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.15-30
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• 2005

The increasing amount of structures presenting distress due to reinforcement corrosion is urging the establishment of more accurate calculation methods for the service life of concrete structures. In the present paper, a summary of the different approaches is presented that are able to calculate the expected life of new structures, in certain aggressive environments or the residual life of already corroding structures. The methods for the initiation period are based on the proper calculation of the carbonation front or chloride penetration and on the steel corrosion rate. The methods for the residual load-bearing capacity calculations are based in the use of ' indicators ' or in the evaluation of the reduced section and a structural recalculation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.57-61
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• 1999

Electrical stress makes insulating materials aged finally resulting in the dielectric failure. It becomes more and more important to recognize the degree of aging and the life time of the insulating materials since it is directly concerned with the reliability of the insulation system. In this paper, the life time of the Cross-linked Polyethylene(XLPE), the insulation layer in the 154kV-grade power cable, is expected and calculated using statistical and mathematical methods. The simulated results are compared with experimental ones and the life exponent of the material is obtained.

• Korean Journal of Organic Agriculture
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• v.15 no.3
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• pp.277-290
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• 2007

This study has been analyzed an execution example of the life cycle assessment on the packaged bean-curd of P company, the first case of the regular life cycle assessment on the processed foods in Korea and considered on the significance and directions of the life cycle assessment on the foods. It is possible to divide the potential environmental impact through the life cycle of the bean-curd into six categories and analyze the environmental impact on the production, use and disposal phases of the product. The values of each environmental impact have been quantified from the strength of the potential impact fur the corresponding category of impact. In the future, it is expected that the result of the lift cycle assessment will be increasingly used fur many areas such as Climate Change Convention and ISO22000, etc. and it is required to promote a project to make database through the assessment on the individual corps or types of businesses for it from now on.

• Journal of the Korean housing association
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• v.21 no.5
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• pp.73-81
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• 2010

With rapid development of various information and communication technologies, to forecast future became important for coping with new environment. Experts in each field of study are forecasting future society, and considerable life scenarios are derived in the process. Life scenarios help people to approach and understand future circumstances easily. Therefore, to study future housing with life scenarios as materials will be helpful to establish the direction to the development of current housing. The purpose of this research is to examine what characterizes the housing functions and life behaviors of future house and what is changing from the housing functions and life behaviors of past and present. Content analysis was used as research method. The subject was 10 future forecasting books which reflects daily life in the house, and 1 episode relating residential space as 1 analysis unit, the total of 213 episodes were analyzed as materials. As a result, most of the life behaviors in the house are expected to be performed by robots instead of humans in the future. On the other hand, partial life behaviors are already being performed mostly by computer system, and another partial life behaviors show that the role-performance of them are not being totally by robots but partially with human.