• 대한전기학회논문지:전력기술부문A
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• 제52권7호
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• pp.414-420
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• 2003

The domestic needs for larger capability of power sources are increasing to cope with the expanding power load which results from the industrial developments & the progressed life style. In summer, the peak load is mainly due to the non-industrial reasons such as air-conditioners and other cooling equipments. To cover the concentrated peak load in stable, the power transmission lines should be more constructed and efficiently operated. The ampacity design of the underground cable system is generally following international standards such as IEC287, IEC60853 and JCS168 which regards the shape of 100% daily full power loads. It is not so efficient to neglect the real shapes of load curves generally below 60~70% of full load. The dynamic (real time) rating system tends to be used with the measured thermal parameters which make it possible to calculate the maximum ampacity within required periods. In this paper, the CTM(Conductor Temperature Monitoring) which is the base of dynamic rating systems for tunnel environment is proposed by a design of lumped thermal network ($\pi$-type thermal model) and distribution temperature sensor attached configuration, including the estimation results of its performances by load cycle test on 345kV single phase XLPE cable.

• 한국화재소방학회논문지
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• 제24권2호
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• pp.126-132
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• 2010

2006년 1월 9일부터 시행되고 있는 주택 성능 등급 표시제도는 능동적(Active)대책으로서의 인명안전 확보에 대해 어느 정도의 등가성을 확보 할 수 있는 소방시설의 품질 및 성능 향상에 관한 내용을 포함하는 것으로 화재 안전의 확보차원에서 매우 바람직한 방향의 정책이라 보여 진다. 본 연구는 현재 국내에서 시행되고 있는 주택성능등급 표시제도의 항목 중 "화재-소방" 분야의 등급시행 활성화를 위해 각 성능 등급 분야에 대한 이론적 배경을 고찰하고 세부 평가 방식에 대한 합리적 개선점을 도출하기 위해 수행되었다. 연구 결과, 현행 주택 성능등급 제도에 따른 "화재-소방" 분야의 성능 향상을 위해서는 성능 등급 세부 항목에 대한 배점 기준을 상향시키는 제도적 정부 시책이 우선적으로 뒷받침 되어야 하고, 아울러 소방 관계법 규정의 시급한 관련 법규 제정이 필요 하다는 전제조건이 선결되어야함을 알 수 있었고, 이를 바탕으로 현행 세부 평가기준에 대한 개선안을 제시하였다.

• 자원리싸이클링
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• 제27권2호
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• pp.11-23
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• 2018

자원고갈, 원자재 가격상승 그리고 환경규제 강화 등의 원인으로 자동차 부품의 재제조 필요성이 요구되고 있다. 재제조를 위해서는 코어의 안정적인 수급이 수반되어야 한다. 현재 재제조 기업은 다양한 경로를 통하여 코어를 회수하고 있지만, 폐자동차에서 발생하는 코어의 회수율은 저조한 편이다. 매년 수십만대가 발생하는 폐자동차에서의 코어를 체계적으로 회수할 수 있다면 재제조를 위한 코어의 회수율을 더욱 향상시킬 수 있을 것이다. 따라서 본 논문에서는 폐자동차에서 발생하는 코어를 회수하기 위한 방안으로 폐자동차에 대한 등급분류체계를 확립하고자 하였다. 우선 등급 분류에 영향을 주는 요소들을 선정하고 평가를 위한 범위를 결정하였다. 다음 영향요소들 간의 가중치를 산정하여 최종 등급 분류 체계를 구축하였다. 마지막으로 사례연구를 통해 실제 입고된 폐자동차의 해체 등급을 평가하여 2등급의 판정을 도출하였다.

• Tribology and Lubricants
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• 제32권1호
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• pp.18-23
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• 2016

The effective case depth for case-hardened rolling bearing has been discussed. For this purpose, rolling contact fatigue tests for ball bearings built with inner race of various hardness values were conducted until L₁₀ calculating rating life using a bearing life test machine under radial loading. Then, the distribution of residual stress below the inner raceway, which depended on the hardness value, was measured by X-ray diffraction. As a result, the linear relationship was established between the hardness value of the inner race and the theoretical shear stress evaluated at the depth where the residual stress disappeared below the inner raceway. Based on the relationship, it could be found that the factor of safety in bearing manufacturer’s rules for the effective case depth of case hardened rolling bearings was set higher. However, it could be also found that the hardness values at the depth where the maximum shearing stress acted below the raceway surface in a tapered roller bearing hardened by the carburizing process, were not sufficient for preventing plastic deformation under the basic dynamic load rating. Consequently, further efforts were still required to reduce or to disperse the contact load on the material design of a rolling bearing in order to prolong its life.

• 아동학회지
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• 제32권2호
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• pp.87-104
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• 2011

The purpose of this study was to develop a basic life habit scale for infant early childhood. The participants of this study were composed of 1,000 parents of children aged from two to five years old in the Seoul, Gyeong-gi, and In-cheon areas. For the purposes of data analysis, the study made use of the following methods : descriptive statistics for SES variables, item-analysis, factor analysis for validity, and Cronbach's a for reliability. Most items were acceptable in terms of item response rates, and item discrimination. The results of factor analysis uncovered six factors, and 46 items were selected from a total of 69 items in the original scale. The six factors were (1) safety and rules (2) neatness (3) manners (4) self-help (5) eating habits (6) cleanliness. Cronbach's a value for the reliability of the factors ranged from .76 to .94.of Cooperative Learning. Methods. Westport, CT : Greenwood Press.

• The Journal of Korean Physical Therapy
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• 제28권1호
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• pp.39-45
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• 2016

Purpose: Physical therapists are likely to be exposed to work-related musculoskeletal pain due to excessive repetitive tasks. This study was conducted to identify the relationship between work-related musculoskeletal pain and quality of life of physical therapists. Methods: A self-reported questionnaires was sent to 200 physical therapists at in Seoul and Kyoungido. The questionnaires was returned by 170 physical therapists. The questionnaire had included 4 items that coveringed demographic information, areas of musculoskeletal problems, pain rating scale, and WHOQOL-BREF. The analysis was completed using descriptive statistics, and differences between pain and demographic variables were identified using the chi-square test. The relationship between work-related musculoskeletal pain and quality of life was analyzed by t-test and Pearson's correlation. Results: The overall prevalence of work-related musculoskeletal pain was 76.8%. The most affected pain sites included the low back (48.8%), shoulder (45.,2%), hand and wrist (43.5%), and neck (33.3%). Pain ratings of subjects with pain was were moderate. There was a A significant difference for the subdomains of quality of life was observed between the subjects with musculoskeletal pain and those without pain. Weak negative correlations (r=-0.28) were observed between pain rating scale and QOL. Conclusion: These findings show that physical therapists appear to be at a higher risk for work-related musculoskeletal pain and physical domain of QOL. Therefore, Ffurther research is needed to investigate examine the effect of risk factors and ergonomics as physical load, general health status on prevalence of musculoskeletal pain.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.441-442
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• 2008

• 대한기계학회논문집
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• 제18권7호
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• pp.1654-1663
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• 1994

Even if the ball bearing was conservatively designed considering the dynamic capacity and the rating life, sometimes the bearing was early failed on account of the misalignment and the lubricant contaminations etc. Misalignment was generated when bearing-shaft system transmitted large power and when the bearing was inadequately mounted. It was possible to predict the fatigue life of ball bearing under the misalignment considering the motions of ball, cage and raceway, and the factors of the effect on fatigue life. Misalignment affected on ball bearing as radial and moment load and the relationships between misalignment and moment were obtained. In this paper, the analysis of the load distributions between ball and raceway, and the prediction of fatigue life of deep groove ball bearing under radial and moment loads were carried out. And, the new formulation of equivalent dynamic load considering the effects of moment load was proposed.

• 대한화학회지
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• 제58권6호
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• pp.622-629
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• 2014

이 연구는 최근 5년간(2009년~2013년) 전국과학전람회 학생부 화학부문 수상 작품의 '탐구대상' 변화 추이, '독창성' 평가등급과 실제 수상등급과의 상관관계를 분석하였다. 이를 위해 각 작품들에서 다루어진 '탐구대상'을 6가지 항목별로 분석하였고, 두 평가자 집단(연수 참여 교사, 수상 경험 교사)의 설문조사를 통해 각 작품의 '독창성' 평가등급을 분석하였다. 각 작품에서 다룬 '탐구대상'의 변화 추이를 분석한 결과, 초등학교에서는 '일상생활', '자연현상', 중학교에서는 '일상생활', '학문', 고등학교에서는 '학문'에서 탐구대상을 선정하도록 지도하는 것이 좋을 것이다. 주제의 '독창성' 평가등급과 실제 수상등급 간의 상관관계를 알아본 결과, 두 등급 사이에는 뚜렷한 상관이 없었으므로 다양한 영역을 종합적으로 고려해 지도하는 것이 좋을 것이다.

• 생물정신의학
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• 제18권4호
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• pp.254-259
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• 2011

Objectives The aim of this study was to assess variations in caudate volume according to dopamin receptor D2/ankyin repeat and kinase domain containing 1 (DRD2/ANKK1) Taq 1a polymorphisms in young healthy adults and to evaluate the relationship between caudate volumes and psychiatric symptoms as measured by the Brief Psychiatric Rating Scale. Methods Genetic information regarding DRD2/ANKK1 Taq 1a and T1-weighted brain magnetic resonance images were acquired from 30 young healthy adults. Automatic segmentation of caudate was performed using the FreeSurfer program. Results Individuals with A2 homozygotes of DRD2/ANKK1 Taq 1a polymorphisms (n = 10) had greater right caudate volumes compared to those with A1 allele (s)(18.4% greater ; p = 0.019). Right caudate volumes were negatively associated with total scores of the Brief Psychiatric Rating Scale (${\beta}$=-0.50 ; p = 0.016). Conclusions Our findings suggest the possibility that DRD2/ANKK1 Taq 1a polymorphisms may underlie the psychiatric symptoms by influencing the structure of the right caudate.