• 한국안전학회지
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• 제36권3호
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• pp.7-14
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• 2021

Hybrid laminated Al/carbon-fiber-reinforced plastic (CFRP) composites are attracting considerable attention from industries such as aerospace and automobiles owing to their excellent specific strength and specific rigidity. However, when this material is used to fabricate high-pressure fuel storage containers subjected to repeated fatigue loads, fatigue life evaluation for the working load is regulated as an important criterion for operational safety and ease of maintenance. Among the existing evaluation methods for these vessels, the burst test and the hydraulic repeat test require expensive facilities. Thus, the present study aims to develop an improved fatigue life test for Al/CFRP laminated hybrid composites. The test specimen was manufactured using a curved mold considering the shape of a type III high-pressure storage container. The strain-life method was used for fatigue life evaluation, and the life was predicted based on the transition life. The results indicate that the more complex the CFRP stacking sequence, the longer is the transition life. This test method is expected to be useful for ensuring the fatigue safety and economy of hybrid laminate composites.

• 한국식품영양학회지
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• 제25권1호
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• pp.205-213
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• 2012

This study investigated the life cycle of menus and made suggestions on the appropriate time for when new menus should be developed. For this purpose, a total of 636 customers who visited 'T' Restaurant more than 25 times in the past three years were used for analysis. After estimating product life cycles based on sales and selling period, an empirical study was conducted. In terms of product life cycle, a growth stage was observed in the category of pasta and pizza in both stores A and B, whereas sales in the rice category stayed constant. Regarding trend in seasonal sales, a big difference was detected between the two stores. While store A was already in the decline stage of the life cycle in all menu categories, store B remained in the growth stage. In terms of menu life cycle, the product life cycle of long-lived products was observed in the pasta category in both stores A and B. While the pizza category was in the growth stage, the product life cycle of long-lived products was observed in the rice category. It is expected that the results of this study could be useful in development of new menus and product life cycle management to fulfill diverse customer needs in the dining-out business.

• 한국주거학회논문집
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• 제27권3호
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• pp.1-9
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• 2016

It is essential to maximize the advantages of long-life housing in consideration of the occupants' demands in order to promote the construction of long-life housing. The diverse plan types with flexibility should be developed based on those demands. Therefore, this study aims to review the level of awareness of long-life housing, and identify the customer needs by conducting the survey for the preference to pre-defined plan types. The results of survey are as follows: 1) Despite the enforcement of the Long-life Housing Certification System in 2014, the recognition among the customers about the long-life housing is still on the low level as shown in that 79.9% of respondents were not aware of the long-life housing; 2) For three alternative plan types, 78.5% on the integration type in front, 63.1% on the moving kitchen type, 47.0% on the Divided Housing type had intention to change; 3) 68.9% of the total are willingly ready to purchase the long-life housing under the condition of no difference in price between normal apartment and long-life housing. The less the number of family members is, the bigger this ratio of positive purchase intention is. Reflecting these results into the designs is expected to contribute to the enhancement of customer satisfaction as well as the diffusion of long-life housing.

• Journal of Preventive Medicine and Public Health
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• 제50권4호
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• pp.240-250
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• 2017

Objectives: Subjective life expectancy (SLE) has been found to show a significant association with mortality. In this study, we aimed to investigate the major factors affecting SLE. We also examined whether any differences existed between SLE and actuarial life expectancy (LE) in Korea. Methods: A cross-sectional survey of 1000 individuals in Korea aged 20-59 was conducted. Participants were asked about SLE via a self-reported questionnaire. LE from the National Health Insurance database in Korea was used to evaluate differences between SLE and actuarial LE. Age-adjusted least-squares means, correlations, and regression analyses were used to test the relationship of SLE with four categories of predictors: demographic factors, socioeconomic factors, health behaviors, and psychosocial factors. Results: Among the 1000 participants, women (mean SLE, 83.43 years; 95% confidence interval, 82.41 to 84.46 years; 48% of the total sample) had an expected LE 1.59 years longer than that of men. The socioeconomic factors of household income and housing arrangements were related to SLE. Among the health behaviors, smoking status, alcohol status, and physical activity were associated with SLE. Among the psychosocial factors, stress, self-rated health, and social connectedness were related to SLE. SLE had a positive correlation with actuarial estimates (r=0.61, p<0.001). Gender, household income, history of smoking, and distress were related to the presence of a gap between SLE and actuarial LE. Conclusions: Demographic factors, socioeconomic factors, health behaviors, and psychosocial factors showed significant associations with SLE, in the expected directions. Further studies are needed to determine the reasons for these results.

• 한국융합학회논문지
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• 제9권7호
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• pp.141-147
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• 2018

치위생과 학생들의 스트레스 부분을 스트레스 반응 척도를 이용하여 체계적으로 분석하여 대학생활 만족도와의 관련성을 파악하기 위하여 경남지역에 소재한 치위생과 학생 299명을 대상으로 스트레스, 스트레스 반응척도, 대학생활 만족도를 융합연구 하였다. 스트레스 반응척도에 따라 체계적으로 분석한 결과 피로와 좌절, 우울, 분노에서 높은 수치를 나타내었다. 또한 스트레스를 경험한 경우 만족도에도 부정적인 영향을 미쳤다. 스트레스는 심각한 경우 질병으로 이어질 수 있는 부정적인 영향을 줄 수 있다. 대학생활의 스트레스가 부적응과 불만족을 가중 시킬 것을 예상 할 때 스트레스 반응척도를 이용한 체계적인 분석 연구는 스트레스를 줄이고 대학생활 만족도 향상에 분명히 도움이 될 것으로 판단된다. 이에 대한 방안으로 치위생과에 맞는 스트레스 반응 도구의 개발과 분석을 제안한다.

• 한국콘텐츠학회논문지
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• 제14권10호
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• pp.137-150
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• 2014

본 연구는 급속한 한국의 인구 고령화로 노후설계의 필요성이 증대되고 있음에도 불구하고 사회와 다소 소외되어 있는 군인을 대상으로 노후생활인식이 노후설계준비에 미치는 영향을 분석하였다. 연구결과 인구사회학적 특성에 따른 차이는 2개 영역(경제적 여가)의 노후설계준비에서 계급, 학력, 종교, 가정구성에서 유의한 차이를 보였으나 신체적 영역에서는 재산만이 유의한 차이를 보여 군 특성이 반영된 결과를 나타냈다. 예비 전역자의 노후생활인식이 노후설계준비에 어떠한 영향을 미치는지의 연구에서는 노후생활인식을 '성공적인 노후생활의 인식'과 '노후에 예상되는 문제점 인식'으로 상반된 개념의 두 가지 요인을 적용한 결과, 이들은 2개 영역(경제적 여가)의 노후설계준비에 정(+)의 영향을 주는 요인이었으나 신체적 영역에서는 유의하지 않았다. 전직지원교육 학습활동의 조절효과는 노후생활인식 중 '예상되는 문제점 인식'에 조절효과가 나타났으나 '성공노년 인식'요인에는 나타나지 않았다.

• 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.

• 대한통합의학회지
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• 제8권4호
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• pp.117-123
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• 2020

Purpose : VDT (visual display terminal syndrome) can affect individuals who monitor or who work or play using video screens, including those of smartphones. In general, headache symptoms from overuse of these screens can appear due to eye fatigue, muscle pain in the joints of wrists or fingers, and muscle pain in the neck or shoulders. Many studies in the literature have supported standards that seek to prevent these symptoms. The incidence of musculoskeletal diseases caused by the use of smartphones is expected to increase rapidly, particularly among children and young adults, and these diseases are expected to develop into a societal problem. Therefore, in this study we investigate whether tension headaches that develop from smartphone usage can affect forward neck posture, neck pain, and quality of life. Methods : A total of 93 students from University participated in this study. We divided participants into two groups, those with tension headaches (n = 25) and those without (n = 68) and took forward neck measurements. Headaches were classified according to criteria from the International Headache Society and involved bilateral headache position, quality of pressing or tightening pain, mild or moderate pain intensity, and none due to daily physical activity. We surveyed participants using the smartphone addiction diagnosis questionnaire, the Neck Disability Index (NDI), the Headache Impact Test (HIT-6), and the Quality of Life Questionnaire. Results : Although we found no significant differences in tension headaches due to smartphone addiction diagnosis (p = 0.25), SF-36 life quality assessment (p = 0.06), and cranio-vertebral angle (p = 0.07), we found significant differences from the HIT-6 and the NDI (p <.05). Conclusion : Tension headaches are not correlated with smartphone addiction, quality of life, and forward neck angle but do have a correlation with the degree of cervical dysfunction and the effects of the headaches.

• 디지털융복합연구
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• 제7권2호
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• pp.71-81
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• 2009

This paper studied the impact of Internet addiction on school life adaptation of high school students. We searched the literature on Internet addiction for such research and analyzed the impact that Internet addiction has on school life fitness. The SPSS statistics program was used for Internet addiction factor analysis and the analysis was carried out through the structure equation model. The family relation, individual relation, school relation and friend relation factor were deduced to Internet addiction as a result. It was revealed that the individual relation factor among Internet addiction factors had an influence on school life fitness. It is expected that this research will prove helpful in providing preventative education for Internet addiction

• Journal of Microbiology and Biotechnology
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• 제10권6호
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• pp.881-884
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• 2000

A polymerase chain reaction (PCR) was performed to rapidly identify Lactobacillus plantarum from type strains and kimchi samples. The PCR experiments were carried out using specific oligonucleotide primer sets based on the 16S rRNA gene sequences of L. plantarum. The expected DNA amplificate of 419 bp was obtained when either purified DNA or whole cells of L. plantarum strains reacted with LP primers, yet not with any of the other strains. The PCR product was confirmed by DNA sequencing. Accordingly, since the PCR method used is simple, specific, and rapid, it will be useful for monitoring and evaluation L. plantarum in the mixed microbial population found in kimchi.