• 한국철도학회논문집
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• 제8권6호
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• pp.520-524
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• 2005

It is consequential to reduce the environmental impact of a product for sustainable development in 21st Century. In the field of transportation, especially, the technological market concerned about reduction and assessment of greenhouse gas emission is expected to be extended. The LCA gas been esteemed and utilized as a realistic alternative greenhouse gas emission is expected to be extended. The LCA has been esteemed and utilized as a realistic alternative to improve the environment by the assessment of environmental impacts. In this study, simplified life cycle assessment(S-LCA), was performed to analyze the environmental impacts quantitatively, which were produced through the life cycle of a electric motor unit(EMU). The object of the present work is rth investigate main parameters of environmental impacts and to establish the plans to improve the environment impact of EMU. As a result of quantitative assessment for environmental impact and manufacturing, the EMU carbody made of SUS showed acidification(AD) and marine water aquatic ecotoxicity(MAET) the most, while that made of Mild showed high impact of global warning(GW) and abiotic resources depletion(ARD). For the SUS EMU, the high AD and MAET impact is occurred by the discharged pollutants during acid-washing process. Also, high value of GW and ARD for Mild EMU is resulted from the consumption of iron ore, coal and crude oil during manufacturing. Therefore, the environment impact of carbody would be decreased by enhancing of energy efficiency and the lightening the weight of it.

• 한국비블리아학회지
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• 제20권3호
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• pp.97-114
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• 2009

도서관의 역할 및 서비스는 전통적으로 정보기술의 변화에 많은 영향을 받으면서 발전하여 왔다. 최근 새로운 정보 기술로서 유비쿼터스 기술이 의학, 건축, 상거래, 방송통신 등의 다양한 분야에서 연구되어지고 있다. 이와 같은 유비쿼터스 정보기술은 도서관에서 제공하고 있는 서비스 및 기능에 많은 영향을 미치고 있다. 유비쿼터스 정보기술의 발전과 함께, 도서관은 역할 및 기능에 있어서 많은 변화가 요구된다. 따라서 본 연구에서는 유비쿼터스 컴퓨팅과 네트워크에 대한 개념과 정의를 알아보았으며 특히, 향후 유비쿼터스 사회의 기술적 기반이 되는 요소기술 및 요구사항과 함께, 도서관의 새로운 역할 및 서비스에 대하여 알아 보았다. 이를 위하여 문헌조사, 사례연구 및 전문가그룹과의 인터뷰를 수행하였다. 이를 통하여 본 연구에서는 유비쿼터스 환경에서의 도서관 서비스 및 역할은 두 가지 관점 즉, 네트워크 및 물리적 공간을 기준으로 고려되어져야 함을 제안하였다. 또한 도서관은 전통적인 정보제공기관으로서 뿐만이 아니라 문화기관 및 교육기관으로서 역할이 더욱 확대되어질 것이며 이를 위한 개인화 및 문화 교육서비스를 위한 프로그램의 개발이 요구된다.

• Journal of Welding and Joining
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• 제17권6호
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• pp.78-83
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• 1999

Solder joint is the weakest part which connects in mechanically and electronically between package body and PCB(Printed Circuit Board). Recently, the reliability of solder joint become the most critical issue in surface mounted technology. The solder joint interconnection between plastic package and PCB is susceptible to shear stress during thermal storage due to the mismatch in coefficient of thermal expansion between plastic package and PCB. A general computational approach to determine the effect of solder joint shape on the fatigue life presented. The thermal fatigue life was estimated from the engelmaier equation which was obtained from the temperature cycling loading($-65^{\circ}C$ to $150^{\circ}C$). As result of the simulation, TSOP structure has the shortest thermal fatigue life and the same structure Copper lead has 2.5 times as much fatigue life as Alloy 42 lead. In BGA structure, fatigue life time extended 80 times when underfill material exists.

• Preventive Nutrition and Food Science
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• 제6권4호
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• pp.240-243
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• 2001

Fresh pasta was packaged in a modified atmosphere of 22% $CO_2$/78% $N_2$ and compared with a control air package for its quality changes during storage at 8$^{\circ}C$. The modified atmosphere packaging suppressed the microbial growth of total aerobic bacteria and yeasts/molds with a concomitant reduction in the rates of physical and chemical quality changes, and thus successfully extended the shelf life of fresh packs from 20 days of air packs to 40 days based on microbial criterion of 10$^{6}$ cfu/g. The shelf life extension was greater when the initial microbial quality of the product was better.

• 한국정밀공학회지
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• 제13권3호
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• pp.123-131
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• 1996

This paper presents the development of an algorithm for the reliability and life of a hypoid gear axle system (located in the last section of power train) in heavy vehicles. The algorithm is developed about expecting the reliability and service-life for applied loads on each component in the system using the Weibull's probabilistic distribution and the extended Palmgren's model. The probabilistic method is used to results. Also this model is involved in predicting the failure which is related to the number of load cycles with the approaching load. Then the precious evaluation of the reliability and life in the axle system can be effectively carried out. Thus the general procedures of a reliability and life design, including the mathematical formulation and numerical examples, are illustrated for a hypoid gear axle system.

• 융합경영연구
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• 제7권1호
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• pp.26-38
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• 2019

Purpose - This paper is to review recent literature, by conducting a thorough investigation of the limitations and implications for future research on work-life balance with the focus and linkages between work-life balance practices, machine learning and emotional intelligence, work-life conflict, the correlations between work-life enrichment and work-life balance practices, the relationships between employee job satisfaction and work-life balance, the links between work-life balance and the managerial support. Research design, data, and methodology - The paper will further detail linkages between work-life balance and organizational performance outcomes productivity and innovation. Previous literatures have paid attentions to the link of HR practices and organizational outcomes such as productivity, flexibility, and financial performance, but the understanding needs to be extended to involve innovation performance. Dealing with employees' emotions using different machine learning techniques is one of the phenomenal researches in today's world. Here, we examine how far the employees are conscious of their own self and found the ideas and views of an individual about themselves and others. Without proper knowledge about their personality it will be very difficult for an individual to manage their own emotions. This study also aims at finding out the individual abilities to manage their emotions in order to perform well. Conclusions - A theoretical conceptual framework has been built by integrating the existing literature to explain a number of factors which are closely associated with work-life balance. The conceptual model illustrates how the work-life balance interplays with performance and interrelates with the aforementioned factors.

• Molecules and Cells
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• 제28권3호
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• pp.209-213
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• 2009

Caenorhabditis elegans is a free living soil nematode and thus in its natural habitat, C. elegans encounters many different species of soil bacteria. Although some soil bacteria may be excellent sources of nutrition for the worm, others may be pathogenic. Thus, we undertook a study to understand how C. elegans can identify their preferred food using a simple behavioral assay. We found that there are various species of soil bacteria that C. elegans prefers in comparison to the standard laboratory E. coli strain OP50. In particular, two bacterial strains, Bacillus mycoides and Bacillus soli, were preferred strains. Interestingly, the sole feeding of these bacteria to wild type animals results in extended lifespan through the activation of the autophagic process. Further studies will be required to understand the precise mechanism controlling the behavior of identification and selection of food in C. elegans.

• 산업경영시스템학회지
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• 제32권1호
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• pp.130-136
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• 2009

Estimation of mortality behavior of a industrial property are useful for calculating depreciation and making management decisions relating to property. The common methods of computing depreciation require an estimation of service life, and some methods may require an estimate of life expectancy. Estimation of service life and life expectancy can be computed from a smoothed and extended life table of original life tables developed through life analysis techniques. Several actuarial techniques are available to construct a life table for depreciation application. Of these methods, the graphic approach and graduation by mathematical formula are the most widely used in the field of depreciation. A commonly used technique of smoothing and of extending the life table is to fit a lows type survivor curves to the observed retirement rate by the least square method. In this paper, estimates of depreciation rate based on directly observed data of the domestic petrochemical equipments are presented.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2006년도 학술발표대회 논문집
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• pp.48-54
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• 2006

In this thesis, accelerated life test (ALT) method and procedure for rubber O-ring are applied to assure specified reliability of the products at guaranteeing the life of the products. Rubber O-ring is parts that keep intensity or make machine operation smoothly on attrition portion of machine and is used to prevent that oil is leaked. Usually. Rubber O-ring used NBR that is copolymer of acrylonitrile and butadiene. this are superior oil resistance, heat resistance, durability of abrasion, cold resistance, chemical resistance etc. The accelerated life test model for rubber O-ring are developed using the relationship between stresses and life characteristics of products. Using the accelerated life test method and the acceleration life test equipment which is developed, we performed life test, collected life data and analyzed the results of tests. The proposed accelerated life test method and procedure may be extended and applied to testing similar kinds of products to reduce test times and costs of the tests remarkably.

• 한국재료학회지
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• 제10권2호
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• pp.128-137
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• 2000

가스터빈 블레이드 재료로 사용되는 IN738LC 니켈기 초합금 주조재에 대하여 고온등압압축(HIP) 공정에 의한 미세조직 변화와 고온 피로수명에 미치는 영향을 조사하였다. 세부적으로 HIP 처리에 따른 주조결함 제거와 피로변형 열화재의 물성재생효과 확인에 중점을 두었으며, 이를 위하여 회전굽힘 피로시험을 실시하고 변형전후의 미세조직을 광학 및 주사전자현미경으로 관찰하였다. HIP 처리 전후의 미세조직과 피로수명을 비교, 평가한 결과, 주조재와 열처리재의 피로수명 차는 크지 않았으나 HIP 처리재의 피로수명은 이들과 비교하여 평균 60배 이상 증가한 것으로 나타났다. 또한 인위적으로 고온 피로변형을 가한 열화재를 대상으로 반복 HIP 처리한 결과, 열화 변형조직이 신재 상태로 거의 완전히 재생될 뿐만 아니라, 재료내에 미세하게 잔존하던 주조결함까지 부가적으로 제거됨에 따라 반복 HIP 처리에 의한 피로수명 연장 효과가 크게 나타났다.