• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2002년도 추계학술대회논문집
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• pp.118-123
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• 2002

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.123.2-123.2
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• 2010

Fuel Cell cogeneration system is a promising technology for generating electricity and heat with high efficiency of low pollutant emission. We have been developed 5kW class fuel cell cogeneration system for commercial and residential application. The fuel processor is a crucial part of producing hydrogen from the fossil fuels such as LNG and LPG. The 5kW class high efficiency fuel processor consists of steam reformer, CO shift converter, CO preferential oxidation(PrOx) reactor, burner and heat exchanger. The one-stage CO shift converter process using a metal oxide catalyst was adopted. The efficiency of 5 kW class fuel processor shows 75% based on LHV. In addition, for the purpose of continuous operation with load fluctuations in the commercial system for residential use, load change of fuel processor was tested. Efficiency of 30%, 50%, 70% and 100% load shows 75%, 75%, 73% and 72%(LHV), respectively. Also, during the load change conditions, the product gas composition was stable and the outlet CO concentration was below 5 ppm. The Fuel processor operation was carried out in residential fuel cell cogeneration system with fuel cell stack under dynamic conditions. The 5kW class fuel processor have been evaluated for long-term durability and reliability test including with improvement in optimal operation logic.

• Educational Technology International
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• 제19권1호
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• pp.123-151
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• 2018

This study aims to examine the effects of self-directed learning readiness (SDLR) on academic performance and the perceived usefulness for each elements of flipped learning. Based on their SDLR scores, 69 students were assigned to a high SDLR group and a low SDLR group. Academic performance was measured by the completion rate of a pre-class online learning and the final exam score, and perceived usefulness for each element of flipped learning was measured by a survey designed by the researcher. For academic performance, the high SDLR group showed a significantly higher completion rate than the low SDLR group, but no significant difference was observed in their final exam scores. Students in the high SDLR group perceived in-class student-centered activities as more useful than those in the low SDLR group. Additional qualitative analyses indicated that students needed more support from instructors and well-prepared peers. Finally, this study suggested that more examination on the various learning characteristics that may influence the effectiveness of flipped learning should be done.

• International Journal of Reliability and Applications
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• 제15권2호
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• pp.111-123
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• 2014

A new class of bivariate distributions is derived by specifying its conditionals as the exponential and gamma distributions. Some properties and relations with other distributions of the new class are studied. In particular, the estimation of parameters is considered by the methods of maximum likelihood and pseudolikelihood of a special case of the new class. An application using a real bivariate data is given for illustrating the flexibility of the new class in this context, and, also, for comparing the estimation results obtained by the maximum likelihood and pseudolikelihood methods.

• 대한치과교정학회지
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• 제20권1호
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• pp.123-133
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• 1990

The work was undertaken to evaluate the calcification of the second and the third molars in skeletal Class II and III malocclusions. The differences in the calcification stages between skeletal Class II and III malocclusion were evaluated and statistically analysed from panoramic radiographs of 202 males and females ranging in age from 11 to 15 years old. The results were as follows, 1. The calcification stages of the second and the third molars were not different between the skeletal Class II and III malocclusions in each age groups of both sexes. 2. The calcification stages of lower second and third molars of the skeletal Class III malocclusion are more advanced than those of the skeletal Class II malocclusion in male. 3. The clacification stages of upper second and third molars are more advanced than those of lower second and third molars in skeletal Class II malocclusion. 4. The calcification stages of lower second and third molars are more advanced than those of upper second and third molars in skeletal Class III malocclusion.

• 대한치과교정학회지
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• 제9권1호
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• pp.117-123
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• 1979

The aspects examined in the present study concerning the location and position of the lower third molar and the interrelationships of this molar, the gonial angle, and the second lower molar in subjects aged 8-24 are based on measurements made from 472 orthopantomograms. The following conclusion were drawn on the basis of the present study. 1. The gonial angle decreased with age, but slight enlarging occurred in the age group 20-21. 2. The angulation of the third molar in relation to the second molar did not correlate with the size of the gonial angle but decreased with developmental stage. 3. The mesial angle between the longitudinal axis of the second molar and the mandibular base line correlated significantly with the gonial angle. The above angle were smaller in Class II, Divison 2 and larger in Class III than in Class I and Class II, Division 1. 4. The rate of presence of lower third molar was 74.4%.

• 영재교육연구
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• 제24권6호
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• pp.935-959
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• 2014

본 연구에서는 서울지역 초등과학영재학급의 영재교사를 대상으로 이들의 영재교육 운영에 대한 경험의 의미를 탐색하고자 하였다. 본 연구의 대상은 저소득층 밀집지역에 위치한 단위 학교 초등과학영재학교 영재교사 4명이며, 연구 참여자에게 인터뷰를 실시하고 현상학적 연구 방법인 Giorgi 분석 방법을 사용하여 이들의 영재교육 운영 경험의 의미를 분석하였다. 영재교사들의 느낌, 생각, 행동, 생활변화를 중심으로 연구 참여자의 경험을 분석한 결과 총 123개의 유의미한 진술을 도출하였고, 이를 바탕으로 총 26개의 주제와 12개의 중심의미를 규명하였다. 이렇게 분석된 중심의미와 주제를 토대로 영재교사의 경험이 가지는 의미에 대하여 상황적 구조적 진술과 일반적 구조적 진술을 하였다. 단위학교 초등과영재학급 운영에서 영재교사가 경험하는 문제점에 대한 이해를 토대로 단위학교 수준에서의 영재학급 운영에 대한 개선점 등에 대한 시사점을 제안하였다.

• 천문학논총
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• 제23권2호
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• pp.123-128
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• 2008

Productivity of the Giant Magellan Telescope is estimated based on the annual number of papers produced by the currently operating large telescopes such as the telescope at the ESO La Silla observatory, CFHT, AAT, the Magellan telescopes, ESO VLT, Japanese Subaru, the Gemini telescopes, and the Keck telescopes. We find that the amount of papers produced by a large telescope is roughly proportional to the diameter of its primary mirror. With this fact, we estimate the SCI-paper productivity of the Giant Magellan Telescope by extrapolating the productivity of the above-mentioned large telescopes. Moreover, according to the paper written in 2001 by Benn and Sanchez, the amount of highly-cited papers produced by a large telescope is roughly proportional to the light-gathering power of the telescope or the square of the diameter. Hence, we survey the productivity of Nature-class papers of the large telescopes and extrapolate the relationship to estimate the productivity of the Nature-class papers by using the Giant Magellan telescope of a filled aperture 21.4 meters in diameter. We expect that Korean astronomers will be able to produce annually 60 SCI-class papers and 20 Nature-class papers with high scientific impact by using the telescope-time corresponding to the 10% share of the Giant Magellan Telescope.

• 한국수학교육학회지시리즈A:수학교육
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• 제40권1호
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• pp.113-123
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• 2001

We investigated an irrational constant e and compared its computational methods using spreadsheet. Such methods are based on classical definition, infinite series, continued fraction, infinite product exponential function and accelerated classical method. This kind of work is focused on experimental mathematics using computers in math class. This approach will be helpful for mathematics teachers to teach constant e in their classroom.

• 대한치과교정학회지
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• 제19권1호
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• pp.123-135
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• 1989

This study was undertaken to investigate the relationship between the depth of antegonial notch and the craniofacial morphology, and to predict the mandibular growth direction & potential in class III malocclusion. The computerized analyses were carried out on longitudinal lateral cephalometric radiographs of 50 children with class III malocclusion, divided into two groups ; 30 deep notch subjects (more than 2.6mm) and 20 shallow notch subjects (less than 1.5mm). The conclusions were as follows: 1. The mandibular growth direction in deep notch group was more vertically directed than in shallow notch group. 2. Deep notch group had shorter anterior & posterior cranial base than shallow notch group. 3. There was not significant difference between deep & shallow notch groups in the amount of mandibular growth during treatment period. 4. Notch depth increased in both deep & shallow notch groups during treatment period.