• 한국화재소방학회논문지
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• 제25권4호
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• pp.48-55
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• 2011

차동식 스포트형 공기 팽창식 열감지기를 인공 가속열화 시켰을 때 발생하는 고장 원인에 대하여 분석하였다. 감지기에 고장이 발생하는 원인은 감열실 금속을 고정하는 접합재(binder)가 플라스틱 몰딩(moulding)에서 분리되어 발생하는 고장과, 감열실 금속과 다이어프램 금속을 고정하는 플라스틱 몰딩에 균열이 발생되는 고장으로 확인되었다. 고장이 발생하지 않은 감지기는 감열실 금속 및 다이어프램 금속이 플라스틱 몰딩에 접합재로 완전히 부착되어 있었다. 또한 2010G 감지기는 접합재의 기계적 강도를 향상시키기 위하여 접합재에 유리강화섬유가 추가되었음이 확인되었다. 감지기 종류별에 따른 플라스틱과 접합재의 밀도에는 큰 차이가 없었다. 그러나 감지기의 플라스틱에 대한 열중량분석(TGA) 결과, 제작년도는 같지만 제조회사가 다른 2005A와 2005B의 플라스틱 열적특성이 동일하지 않은 것으로 확인되었다.

• Journal of Preventive Medicine and Public Health
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• 제38권1호
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• pp.61-70
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• 2005

Objectives : To develop a tool for multidimensional measurement of the quality of life, which was psychometrically sound, short, and easy to administer for patients with hypertension. Methods : A sample of 1,115 hypertensive patients aged 20 or above in Cheong-Song County was studied from June 1997 to October 1998. In the development of the instrumental stage, the authors first conceptualized the quality of life. Item generation, item reduction, and questionnaire formatting were followed. Item-level (item descriptive, missing%, item internal consistency, item discriminant validity) analysis, scale-level (scale descriptive, floor and ceiling effect) analysis, and other tests(Cronbach's alpha, inter-dimension correlations, factor analysis, clinical validity) were performed to evaluate the validity and reliability of the new measurement scale. After 1 year, responsiveness and confirmatory factor analysis were performed. Results : The results of both item-level and scale-level analyses were acceptable. An acceptable degree of internal consistency was observed for each of the dimensions (Cronbach's alpha was 0.60 or higher). Inter-dimension correlations were below 0.50 and the factor analysis result was the same as the intended dimension structure. Correlation coefficients between perceived health status, stress and dimensions were proven to be acceptable. The result of comparing dimensional score means among ADL and MMSE-K groups above 60 years was statistically significant(p<0.05). The result of confirmatory factor analysis concluded that the dimensional structure model was well fitted. However, the result of responsiveness test using sensitivity and specificity was unsatisfactory. Conclusions : The newly developed measurement scale is psychometrically reliable and valid instrument for measuring quality of life in hypertensive patients.

• Journal of Welding and Joining
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• 제28권1호
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• pp.66-71
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• 2010

With large specific strength and outstanding corrosion resistance and erosion resistance in sea water, titanium and titanium alloy are widely used in heat exchanger production. In particular, pure titanium demonstrates outstanding molding performance and may be considered optimal for production of heat exchanger. Since titanium is very vulnerable to oxidation and embrittlement during welding, processes with less heat input are widely used, and laser welding is widely applied by considering production performance and shield etc in atmosphere. So far, 1st report and 2nd report compared and analyzed embrittlement degrees by bead colors of weldment through oxygen and nitrogen quantitative analysis and hardness measurement, and evaluated welding performance and mechanical properties of butt welding. This study evaluated field applicability of lap welding to heat exchange plate of LPG re-liquefaction device for ships through tensile stress test, hardness test and internal pressure test etc after deducing optimal weding condition and applying to actual heat exchange plate. In bead overlap area, the experiment produced sound welds with no porosity or defect by increasing and decreasing laser power, and tensile-shear test results indicated virtually the same tension and yield strength as base metal. As a result of measuring hardness at lateral cross section and bead overlap zone of actual heat exchanger welds, hardness difference within 20Hv was produced at base metal, HAZ and weldment, and as a result of pneumatic and hydraulic pressure test, no leakage occurred.

• 한국환경교육학회지:환경교육
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• 제18권1호
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• pp.1-30
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• 2005

Environmental education as worldwide sustainable education is effective when it is carried out as early as possible. But we do not have any aims and textbooks for environmental education in the elementary school. The purpose of this study is systematizing environmental syllabus as sustainable education. To achieve this purpose, firstly, the meaning of environmental education as sustainable education was conceptualized, secondly, the aims of environmental education was set up, thirdly, domains of environmental education was revised, and lastly, the syllabus for environmental instruction were created for each grade. Literature review was practiced over 143 textbooks and teacher's guidebooks from the 4th to 7th curriculum period. The result of this study follows. First, environmental education as sustainable education in the elementary school was conceptualized as an integrative education to keep the lifelong education and welfare. Second, the synthetic aim of environmental education as sustainable education in the elementary school was set up as 'cultivating desirable environmental people that behave for the sustainable future with environment-friendly value and attitude. Third, our environmental domains were divided into 11-12 independent areas, and ESSD (Environmentally Sound and Sustainable Development) was located on the subcategory of environmental domain. These domains were revised into three environmental domains and five sub-domains. Fourth, according to the aims of environmental education as sustainable education and five environmental domains, 253 objectives were established. Fifth, objectives of environmental education of 10 subject matters and integrative objectives were presented. Sixth, based on the objectives of domains and subject matters, 255 contents for environmental education in the elementary school were abstracted and distributed to each grade in the consideration of balance among domains and appropriateness of grades. Seventh, analytic results of textbooks of 7th curriculum shows heavy stress on the 'knowledge perception' section and deficiency on the altitudes and behavior section. The environment-related level and contents overlapped and fragmented deeply. Furthermore, 33 parts of textbooks could bring to mis-concept on environment.

• 한국유체기계학회 논문집
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• 제17권1호
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• pp.35-40
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• 2014

A multi-objective optimization of a regenerative fan for enhancing the aerodynamic and aeroacoustic performance was carried out using an integrated fan design system, namely, Total FAN-Regen$^{(R)}$. The Total FAN-Regen$^{(R)}$ was developed for non-specialists to carry out a series of design process, viz., computational preliminary design, three-dimensional aerodynamic and aeroacoustic analyses, and design optimization, for a regenerative fan. An aerodynamic analysis of the regenerative fan was conducted by solving three-dimensional Reynolds-averaged Navier-Stokes equations using the shear stress transport turbulence model. And, an aeroacoustic analysis of the regenerative fan was implemented in a finite/infinite element method by solving the variational formulation of Lighthill's analogy based on the results of the unsteady flow analysis. An optimum shape obtained by Total FAN-Regen$^{(R)}$ shows the enhanced efficiency and decreased sound pressure level as much as 1.5 % and 20.0 dB, respectively, compared to those of the reference design. The performance test was carried out for an optimized regenerative fan to validate the performance of the numerically predicted optimal design.

• Structural Engineering and Mechanics
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• 제32권2호
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• pp.283-300
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• 2009

The characteristic response of a structure to blast load may be divided into two distinctive phases, namely the direct blast response during which the shock wave effect and localized damage take place, and the post-blast phase whereby progressive collapse may occur. A reliable post-blast analysis depends on a sound understanding of the direct blast effect. Because of the complex loading environment and the stress wave effects, the analysis on the direct effect often necessitates a high fidelity numerical model with coupled fluid (air) and solid subdomains. In such a modelling framework, an appropriate representation of the blast load and the high nonlinearity of the material response is a key to a reliable outcome. This paper presents a series of calibration study on these two important modelling considerations in a coupled Eulerian-Lagrangian framework using a hydrocode. The calibration of the simulated blast load is carried out for both free air and internal explosions. The simulation of the extreme dynamic response of concrete components is achieved using an advanced concrete damage model in conjunction with an element erosion scheme. Validation simulations are conducted for two representative scenarios; one involves a concrete slab under internal blast, and the other with a RC column under air blast, with a particular focus on the simulation sensitivity to the mesh size and the erosion criterion.

• 가족자원경영과 정책
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• 제11권3호
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• pp.23-43
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• 2007

The purpose of this study was to examine how college students' attitudes toward the use of money and credit cards have affected their financial management practices. The data were collected from 231 college students in Seoul using by a self administered questionnaire. Frequencies, factor analyses, t-tests, ANOVA, and multiple regression were conducted using by SPSSWIN 12.0. The results from this study were as follows. First, results of the factor analysis of attitudes toward the use of money were divided into 5 dimensions such as instrument of ostentation, sufficiency of desire, source of anxiety, diligence and economy, and instrument of preparation for the future. Attitudes toward the uses of credit cards were divided into 3 dimensions, such as positive affection, cognition of reverse function, and attitudes of use-behavior. Financial management practices were divided into 2 dimensions: planning and performing. Second, social-demographical & economical factors, among such as gender, allowance, financial stress, number of credit -cards possessed, and expenses of credit -cards totals each month were significant in the regression analyses for the financial management practices. The results indicate that attitudes toward the use of money have a bigger effect on financial management practices than attitudes towards credit cards. Specifically, attitudes toward the use of money as an instrument of preparation for the future had the most effect on the financial management practices. These results imply that for sound financial management practices to take place, there needs to be education on attitudes toward the use of money.

• 비파괴검사학회지
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• 제32권5호
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• pp.484-493
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• 2012

초음파를 사용해 음속도, 감쇠 계수, 밀도, 비선형 B/A 파라미터 등을 측정하여 인체 조직의 특성을 정량적으로 영상화하고자 하는 연구가 1980년대부터 많이 진행되어 왔으나 아직 상용화 단계에는 도달하지 못했다. 하지만 1990년대 초에 시작된 탄성 영상법은 최근 들어 초음파 진단기에 상용화되어 임상에서 B-모드 영상법과 함께 전립선, 유방, 갑상선, 간, 혈관 등을 진단하기 위한 보완적이며 더 정량적인 모드로 사용되고 있는 단계에 진입하였다. 본고에서는 주로 준정적 또는 정적탄성 영상법에 사용되는 여러 가지 알고리듬을 소개하고 특성을 비교하고자 한다. 대부분의 알고리듬은 상호상관함수 또는 자기상관함수 방법에 그 기반을 두고 있으며 전자는 래그를 변화시켜가면서 시간 이동량을 찾지만 후자는 보간 과정 없이 고정된 래그에서의 위상차로부터 시간 이동량을 바로 구해 변위를 추정하는 점이다.

• 한국콘텐츠학회논문지
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• 제19권10호
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• pp.112-125
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• 2019

1인 방송 및 동영상 플랫폼들이 영상 소비를 위한 주요 창구로 자리잡은 상태에서 ASMR 콘텐츠가 새로운 소비의 트렌드로 자리잡고 있다. 이러한 가운데 본 연구는 ASMR 콘텐츠 이용 영향 요인들을 실증적으로 살펴보고자 하였다. 좀 더 구체적으로, 본 연구는 인구사회학적 요인들, 하위 콘텐츠 유형, 이용 동기, 신경증 및 주관적 규범을 영향 가능 요인들로 설정하고 이들의 ASMR 콘텐츠 이용에의 영향력을 실증적으로 규명해보았다. 신경증의 직접 효과 이외에 조절 효과 또한 검증하였다. 분석 결과 인구사회학적 요인들로 교육수준, 마찰 및 입소리 콘텐츠 유형, 이용 동기로서 집중, 수면장애해소, 즐거운쾌감 스트레스해소 및 주관적 규범이 ASMR 콘텐츠 이용에 긍정적 영향을 미치는 것으로 나타났다. 반면 호기심 유행 및 성적 쾌감 동기는 이용에 부정적 영향을 미치는 것으로 나타났다. 신경증의 조절 효과도 발견되었다. 본 연구는 ASMR 콘텐츠 이용을 보다 정확히 이해하기 위해서는 신경증과 같은 이용자의 성격 특성들도 영향 가능 요인으로 고려할 필요성이 있음을 제시하였다는 점에서 의의를 지닌다.

• 한국산학기술학회논문지
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• 제19권1호
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• pp.615-621
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• 2018

본 연구에서는 에너지절감과 실내쾌적성을 높이기 위하여 색온도, 아로마 및 소리 변동리듬의 자극을 가하여 비교분석하였다. 온도$25[^{\circ}C]$, 상대습도 50[RH%], 기류속도 0.02[m/s] 및 조도 1000[lux]가 유지되는 항온항습실에서 뇌파, 심박동 변이 및 바이브라이미지가 측정되었다. 자극 종류는 자극을 가하기 전, 소리 변동리듬 a=1.106 재즈 음원으로 이루어지는 단일자극 그리고 붉은 조명, 아로마향기 및 소리 변동리듬 a=1.106 재즈 음원으로 이루어지는 다감각자극의 세종류로 측정이 이루어졌다. 변동리듬 a=1.106의 재즈 음원, 붉은 조명 및 아로마향기의 다감각자극에서 생산성과 집중력이 향상되었고, 스트레스지수와 피로도가 감소되었다. 또한 변동리듬 a=1.106의 재즈음원, 붉은 조명 및 아로마향기의 다감각자극에서 심박동이 안정되게 유지되었으며, 바이브라이미지의 긴장도와 스트레스 역시 감소되었다. 변동리듬 a=1.106 음원, RED조명 및 쟈스민 향기의 다감각자극이 쾌적성과 집중력 향상에 효과적이라는 것을 알 수 있었으며, 단일감각에 노출되기 전보다 뉴로에너지가 증가한다는 것을 알 수 있었다. 변동리듬 a=1.106 음원, RED조명 및 쟈스민 향기의 다감각자극이 자극을 가하기전보다 또한 단일감각자극을 가했을 때 보다 뉴로에너지가 증가된다는 것을 알 수 있었다.