• 대한지구과학교육학회지
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• 제5권1호
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• pp.8-19
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• 2012

The purpose of this study is to: analyze the characteristics on ill-structured problem-solving process; examine the type of memories used in their monitoring. The data were primary collected from observation and secondary the semi-structured in-depth interviews based on analysis of observation results with two students who belong to science school and a guidance. The findings of this study revealed that the ill-structured problems possess multiple representations and the upper level's problem have several sub-problems. And multiple steps simultaneously exist in particular stage of problem-solving process that is not single sequential but complex flow and have high frequency of discussion step. Type of memories used in ill-structured problems include idiosyncratic memories which is related in personal histories such as school performance, problem-related memories, abstract rules and intuition.

• Steel and Composite Structures
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• 제42권5호
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• pp.591-598
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• 2022

The article deals with the possibilities of vibration stimulation. Based on the stability analysis, a multi-scale approach with a modified whole-building model is implemented. The motion equation is configured for a controlled bridge with a MDOF (multiple dynamic degrees of freedom) Tuned Mass Damper (M-TMD) system, and a combination of welding, excitation, and control effects is used with its advanced packages and commercial software submodel. Because the design of high-performance and efficient structural systems has been of interest to practical engineers, systematic methods of structural and functional synthesis of control systems must be used in many applications. The smart method can be stabilized by properly controlling the high frequency injection limits. The simulation results illustrate that the multiple modeling method used is consistent with the accuracy and high computational efficiency. The M-TMD system, even with moderate reductions in critical pressure, can significantly suppress overall feedback on an unregulated design.

• Advances in nano research
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• 제13권5호
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• pp.475-485
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• 2022

Crystalline silicon photovoltaic cells have advantages of zero pollution, large scale and high reliability. A major challenge is that sunlight wavelength with photon energy lower than semiconductor band gap is converted into heat and increase its temperature and reduce its conversion efficiency. Traditional cooling PV method is using water flowing below the modules to cool down PV temperature. In this paper, the idea is proposed to reduce the temperature of the module and improve the energy conversion efficiency of the module through the modulation of the solar spectrum. A spectrally selective nanofilm reflector located directly on the surface of PV is designed, which can reflect sunlight wavelength with low photon energy, and even enhance absorption of sunlight wavelength with high photon energy. The results indicate that nanofilm reflector can reduce spectral reflectivity integral from 9.0% to 6.93% in 400~1100 nm wavelength range, and improve spectral reflectivity integral from 23.1% to 78.34% in long wavelength range. The nanofilm reflector can reduce temperature of PV by 4.51℃ and relatively improved energy conversion efficiency of PV by 1.25% when solar irradiance is 1000 W/m². Furthermore, the nanofilm reflector is insensitive in sunlight's angle and polarization state, and be suitable for high irradiance environment.

• 대한가정학회지
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• 제43권1호
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• pp.1-15
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• 2005

The purpose of this study was to evaluate the propriety of various aspects of the 7th home economics science curriculum in high school. In this study, home economics education experts participated in a three-round Delphi survey. The findings of this study were as follows: First, the experts evaluated that the subject arrangement and title 'home economics science' were inadequate. Second, the experts evaluated that the characteristics of home economics science were similar to those in prior home economics curricula, and that the characteristics of the subject were also ambiguous. Third, the experts evaluated that the objectives of home economics science were too technically presented, and pointed out that the objectives are not distinct from those of prior home economics courses as they are too general and abstract. Fourth, the experts evaluated that the content of home economics science was deficient in its hierarchy and integration. Moreover, the contents do not sufficiently reflect the characters of the learners or their social demands. Fifth, the experts evaluated that the teaching/learning methods of home economics science were stated for the sake of formality only. Even though it provides many methods, it is not practical in the current educational situation. Sixth, the experts evaluated that although home economics science provides various methods of assessment, it has practical difficulties under current educational circumstances. Besides, the assessment methods failed to give concrete and objective standards.

• 대한간호학회지
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• 제9권1호
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• pp.31-40
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• 1979

The purpose of the study was undertaken to present transition of school nurses to analyze some factors related to them. 1. Overage increase rate of school nurses the year of 8 years (1970 - 1978) was 4.61% for the primary school, 2.14% for the middle school, and 15.26% for the high school which was the highest. The total number of school nurses was 1289. 2. The percentage of school working school nurses to the total schools was 14.6％ for the primary school, 7.1% for the middle school, and 15.2% for the high school in 1918. In Seoul was largest of 66.7% while that of kyongsangnamdo showed the lowest of 1.5%. 3, In 1978, the increase of school nurses was 17.9% for the private school which was highest while that of the nation and public school showed the lowest of 12.4%. 4. Studies for the Primary, middle and high school per school nurses in 1979 were 5,981.14,923.7,655 respectively. 5. Considering the age distribution of the total school nurses for the primary, middle and high schools was the most of 54.1% in 20s. Regarding the, career of school nurses, those who had worked for less than 5 years were 46.4% in 1970, while 51.8% in 1978. And the school nurses who had worked for less than 10 years reduced 71.3% from 82.7%. 6, There were close relationship between the number of school nurses and that of school, and a regression formular made as follow: SNi = -24.497+0.675 Si+ 0,196 Ni (School) (Nurses).

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.416-418
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• 2008

Cost effective and high efficiency energy recovery circuit (ERC) using an address voltage source is proposed. Different from prior ERC, the proposed circuit uses a voltage source to charge a panel and a current source to discharge the panel. As a result, it can be achieved zero voltage switching (ZVS) of switches in H-bridge inverter and zero current switching (ZCS) of switches of the ERC. Moreover, the proposed ERC can obtain high efficiency, high performance and the decrease of the cost and the size.

• 한국과학교육학회지
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• 제14권3호
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• pp.293-303
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• 1994

The purpose of this study was to find the effect of molecular movement model based instruction on high school students' conceptions of diffusion and osmosis. The study was composed of two groups, the traditional instruction group in which the so-called traditional instruction was performed, and the other group in which interventions by researchers were made. The subjects of the traditional instruction group consisted of a total of 242 high school students from Seoul, Gwangju and Mokpo. The subjects of the model based instruction group consisted of 177 first-year high school students in Mokpo. The study was focused on the use of the term of 'molecular movement' in their explanation of diffusion and osmosis in the correct contexts. In general, students who got the molecular movement model based instruction showed more frequent use of the terms of 'molecular movement' in the correct contexts than the control group students did. It was found that misconceptions including teleological explanations changed into scientific explanations by the intervention. It seemed that the molecular movement model led students to make scientific explanations on natural phenomena. A further research is recommended to assess the improvement of teleological explanation and scientific attitude by the molecular movement model.

• Toxicological Research
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• 제29권4호
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• pp.293-298
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• 2013

A method of detecting lead was developed using square wave anodic stripping voltammetry (SWASV) with DNA-carbon nanotube paste electrode (CNTPE). The results indicated a sensitive oxidation peak current of lead on the DNA-CNTPE. The curves were obtained within a concentration range of 50 $ngL^{-1}-20mgL^{-1}$ with preconcentration time of 100, 200, and 400 sec at the concentration of $mgL^{-1}$, ${\mu}gL^{-1}$, and $ngL^{-1}$, respectively. The observed relative standard deviation was 0.101% (n = 12) in the lead concentration of 30.0 ${\mu}gL^{-1}$ under optimum conditions. The low detection limit (S/N) was pegged at 8 $ngL^{-1}$ ($2.6{\times}10^{-8}M$). Results showed that the developed method can be used in real-time assay in vivo without requiring any pretreatment and pharmaceutical samples, and food samples, as well as other materials requiring water source contamination analyses.

• 한국컴퓨터교육학회 학술대회
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• 한국컴퓨터교육학회 2018년도 동계학술대회
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• pp.125-128
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• 2018

오늘날 스마트폰, 태블릿과 같은 모바일 디바이스가 등장하고, 무선 네트워크의 기술이 향상되면서 모바일 쇼핑 이용률이 높아지고 있다. 이에 따라 택배의 사용률도 증가하고 있는데, 택배를 수령하는 일반적인 방법으로 직접 수령하는 것과 공동 택배 보관 장소를 통해 수령하는 것이 있다. 그러나 이러한 방법들은 택배기사와 시간을 정해야 하는 번거로움, 택배기사를 위장한 범죄, 그리고 공동 택배 보관 장소에서의 택배 분실 등과 같은 문제점이 존재한다. 따라서 본 연구에서는 1인 가구와 택배 수령에 어려움을 겪는 가구를 위한 개인 택배 보관 시스템을 개발하였다. 이 시스템은 안드로이드 어플리케이션에서 택배에 부착된 바코드를 스캔하여 그 정보를 아두이노와 블루투스 통신을 통해 전달한다. 이때, 아두이노는 미리 저장된 운송장 번호와 수신한 운송장 번호를 비교하여 택배 보관 시스템의 잠금 장치를 열고 닫는다.

• 한국지구과학회지
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• 제38권3호
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• pp.239-249
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• 2017

이 연구의 목적은 사범 대학 과학교육학부에 재학 중인 예비 과학 교사들을 대상으로 고등학교에서의 지구과학선택 과목의 이수 여부와 대학 전공이 일반지구과학 수업에 대한 태도, 학업 성취도에 미치는 영향을 분석하는 것이다. 이 연구의 대상은 광역시 소재 대학교 과학교육학부 소속의 학생들 중 2012년 2학기부터 2015년 2학기까지 총 4개 학기 동안 일반지구과학 강의를 수강한 273명의 학생들이다. 현재 전공과 고등학교 지구과학 교과목 이수 여부가 일반지구과학 수업에 대한 태도 및 시험 체감 난이도, 학업 성취도에 미치는 영향을 SPSS 23.0을 활용하여 이원분산분석(two-way ANOVA)을 실시하였다. 연구 결과에 따르면, 지구과학교육 전공 학생들과 타 과학교육전공 학생들 사이에는 일반지구과학 수업에 대한 태도와 시험 체감 난이도에 대해서 차이가 없었지만, 고등학교에서 지구과학의 이수 여부는 학생들의 태도와 성취도에 영향을 미쳤다. 즉, 고등학교에서 지구과학 I과 지구과학 II를 모두 이수한 학생은 지구과학 I만 이수한 학생 또는 지구과학을 전혀 선택하지 않은 학생들보다 일반지구과학 수업 태도가 더 좋았으며 높은 성취 수준을 보이는 것으로 분석되었다. 과학 교사를 양성하는 사범 대학의 교육에서는 학생들의 요구와 수준을 반영한 교수학습적 접근이 필요하며, 과학 교사로서 필요한 교과 지식을 효과적으로 학습할 수 있도록 사범 대학 과학과 교육과정의 지속적인 보완이 있어야 할 것이다.