• 한국초등과학교육학회지:초등과학교육
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• 제30권3호
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• pp.379-393
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• 2011

The purpose of this study was to analyze the complexity of scientific reasoning during open inquiry activities of pre-service elementary school teachers. In this study, 6 pre-service elementary teachers who participated in open-inquiry activities were selected. The data of scientific reasoning during their inquiry process was collected from the video recording of reporting about inquiry process and results, their reports and researcher's notetaking. CSRI Matrix (Dolan & Grady, 2010) was used to analyze the complexity of participants' scientific reasoning. The result showed that the degree of the complexity of their scientific reasoning varied in participants. Particularly the low degree of the complexity of scientific reasoning presented in posing preliminary hypotheses, providing suggestions for future research, communicating and defending finding. Also, The more pre-service teachers' epistemology of inquiry are similar to that of scientists, the more complex scientific reasoning represents. This results suggest that teachers should impress on students the importance of doing the precedent study and providing suggestions for future research, and provide a place for communicating and defending findings.

• 한국정보통신학회논문지
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• 제18권8호
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• pp.2029-2036
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• 2014

본 논문에서는 반도체 레이저의 직접 변조를 이용한 광전 발진기의 성능에 대한 이론적인 해석을 수행하였다. 먼저 광전 발진기를 구성 하는 각 부분의 응답 특성을 해석 하고, 이를 이용하여 광전 발진기 전체의 개방 루프 응답 특성을 얻었다. 다음으로 개방 루프 응답 특성의 크기 응답과 위상 응답 해석 결과에 루프 발진기의 발진 원리를 적용하여 광전 발진기의 발진 주파수, 스퓨리어스 톤의 간격, 위상 잡음의 성능을 도출하였다.

• Journal of Biosystems Engineering
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• 제43권4호
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• pp.420-425
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• 2018

Purpose: Chemical fertilizers contribute to agricultural productivity. Annually, 450,000 tons of chemical fertilizers are used in Korea, which is 268 kg per hectare (MAFRA, 2016). However, excessive use causes problems such as environmental pollution and soil acidification. This study proposes use conditions for a fertilizer distributor that can reduce excessive fertilization by analyzing distribution patterns. Methods: This study analyzed fertilizer application uniformity according to the number of blades on a centrifugal fertilizer distributor (three or four blades), orifice gate open ratio (50 or 100%), and blade rotation speed (400, 500, or 600 rpm). Results: When using four blades, the coefficient of variation (CV) was lower than when using three by 11-13% points, and the CV using the 50% open ratio was 10-30% points lower than using the 100% open ratio. The CV at 500 rpm blade rotating speed was 9-12% points lower than that for 400 and 600 rpm. Conclusions: The CV with four blades, 50% orifice gate open ratio, and 500 rpm of blade rotating speed was 18.4%, which provided the most uniform fertilization.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2019년도 제60차 하계학술대회논문집 27권2호
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• pp.321-324
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• 2019

최근 국내에는 실업률 상승, 혼인률 하락 등 청년층 생애주기 변화, 단독거주, 고령층의 증가에 따라 1인 가구가 빠른 속도로 증가하고 있다. 이러한 추세는 지속될 것으로 예상되어 1인 가구를 겨냥한 맞춤형 보안솔루션에 대한 관심이 고조되고 있다. 본 논문에서는 사물 인터넷 기술을 적극적으로 접목할 수 있을 것으로 기대되는 디지털 도어락의 구현에 관한 연구를 수행하였다. 사물 인터넷 기술은 5G 시대의 도래에 따라 다시금 주목받고 있다. 이는 4차 산업혁명 시대의 핵심 기반 기술로 주요 IT 기업들이 상용화 기술 확보를 추진하고 있는 상황이다. 한편 디지털 도어락은 열쇠가 필요하지 않으며 위급상황이나 안전상황에 클릭 한번으로 출동 요원의 출동을 곧바로 요청할 수 있어 고객에게 편의성과 보안성을 제공한다. 하지만 비밀번호 방식의 디지털 도어락은 주기적으로 비밀번호를 교체해주지 않는 이상 지속적으로 같은 자리의 버튼만을 누르게 된다. 이렇게 되면 해당 위치에 지문이 남아서 비밀번호가 노출될 위험이 있다. 그러나 사물 인터넷 기술을 이용한 디지털 도어락을 사용하게 된다면 안전한 도어락 사용으로 주거 보안을 실현할 수 있다. 따라서 1인 가구를 노리는 범죄를 예방하기 위해 라즈베리 파이와 아두이노의 UART 통신, 머신러닝 CV를 이용하여 얼굴 인식으로 동일인임을 판단하는 디지털 도어락을 구현했다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제31권5호
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• pp.422-426
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• 2005

Purpose : The purpose of this study was to investigate the vertical stability after BSSRO surgery in skeletal class III malocclusion patients with mild anterior open bite and to present a method to increase the stability. Materials and methods : 36 patients, 11 male and 25 female, who received BSSRO surgery with the diagnosis of skeletal class III with anterior open bite at the Department of Oral and Maxillofacial Surgery in Samsung Medical Center, from January 2002 to August 2003, were selected for this study. The patients were between 18 to 45 years of age. Preoperative and postoperative (immediate, 6 months, and 1 year after operation) lateral cephalograms were compared to evaluate the vertical stability by measuring the distance of nasion-menton, mandibular plane angle, and overbite. Results : The nasion-menton distance decreased by 1.65mm immediately after the operation in comparison to the preoperative value. This distance further decreased by 0.60 mm at 6 months and 1.06mm at 1 year after the operation. The mandibular plane angle increased after the operation and further increased at 6 months and 1 year. The amount of overbite increased by the operation was 2.34mm and an additional increase of 0.70mm at 6 months and 0.94mm at 1 year were shown. Conclusion : Clinically, none of the patients showed relapse of anterior open bite and the vertical stability is highly influenced by orthodontic treatment after the operation. In this study, BSSRO surgery is considered to be a rather reliable procedure that restores stability to skeletal class III malocclusion patients with slight anterior open bite.

• 한국학교ㆍ지역보건교육학회지
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• 제11권1호
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• pp.67-78
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• 2010

Background & Objectives: Current trend is that funding agencies require investigators to share their data with others. However, there is limited guidance how to access and utilize the shared data. We sought to determine what common data sharing practices in U.S.A. are, what data-related to adolescent health are freely available, and how we deal with the large dataset adopting the complex study design. Methods: The study included only research data-related to adolescent health which was collected in USA and unlimitedly accessible through the internet. Only the raw data, not aggregated, was considered for the study. Major keywords for web search were "adolescent", "children", "health", and "school". Results: Current approaches for public health data sharing lacked of common standards and varied largely due to the data's complex nature, large size, local expertise and internal procedures. Some common data sharing practices are unlimited access, formal screened access, restricted access, and informal exclusive access. The Inter-University Consortium for Political and Social Research and the Center for Disease Control and Prevention were the best data depository. "Data on the net" was search engine for the website providing data freely available. Six datasets related to adolescent health freely available were identified. The importance and methods of incorporating complex research design into analysis was discussed. Conclusion: There have been various attempts to standardize process for open access and open data using the information technology concept. However, it may not be easy for researchers to adapt themselves to this high technology. Therefore, guidance provided by this study may help researchers enhance the accessibility to and the utilization of the open source data.

• 아동학회지
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• 제10권1호
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• pp.1-10
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• 1989

This study compared the effects of open and directed teaching styles on creativity and mathematical achievement. The subjects were 32 three- and four-year-old children enrolled in the Home Economics Laboratory Nursery School at the University of Arkansas during the fall semester of 1987. In this study, the open teaching style was a child-oriented method of teaching with the help or guidance rather than the actual instruction of teacher, while the directed teaching style was a teacher-oriented method of teaching with actual instruction of the teacher. Forty-eight activities and materials relevant to mathematical concepts appropriately designed for the subjects were used. The nursery school children were divided into morning and afternoon groups. Utilizing a Latin square design, the children in the morning group were taught by the directed teaching style for four weeks followed by a three week period of no planned mathematical activities, then taught by the open teaching style for four weeks. The children in the afternoon group followed the same schedule except the open teaching style was first. At the end of the two four-week sessions of mathematics experiences Thinking Creatively in Action and Movement and selected items of Tests of Basic Experiences 2: Mathematics were administered. The scores of each of the two tests were analyzed using a t-test of dependent measures for the two teaching styles, the sex, and the age of the children. Children taught using the directed teaching style showed a significantly higher originality and mathematical achievement scores than those taught using the open teaching style. Differences for sex and age revealed that the directed teaching style was a significantly better method of instruction to foster the originality for boys and the mathematical achievement for four-year-old children.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.469-474
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• 2008

The objective of this study is to propose basic design guidelines for more effective air ventilation system in apartments. It is well known that ventilation depends on whether the room doors are open or closed as well as people's living patterns. This study considers 84 ㎡-sized apartment which has extended living room without balcony. Ventilation of bathroom and kitchen is not considered. The height of the building, external air pressure and air infiltration through the windows are also neglected. The regulation on indoor air quality made it mandatory that the air change per hour be more than 0.7. Four models are suggested to study the effect of open and closed doors. Models 1 and 3 are open door types and models 2 and 4 are closed door types. The open types have 50 mm hole near the top of the door to substitute exhaust outlet. The ventilation effectiveness was evaluated by 3-dimensional numerical simulation using finite volume method by a commercial software. This work compares air flow, temperature of air, age of air and the efficiency of ventilation of apartments with wooden doors of bedroom 1 and 2, which are open or closed.

• Restorative Dentistry and Endodontics
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• 제37권2호
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• pp.68-73
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• 2012

Objectives: The purpose of this study was to assess the accuracy of Root ZX (J. Morita Corp.) according to the location of major foramen and open apex. Materials and Methods: 81 mandibular premolars with mature apices were selected. After access preparation, 27 teeth were instrumented to simulate open apices. 54 teeth were classified according to location of major foramen under surgical microscope (${\times}16$). The file was fixed at the location of apical constriction by Root ZX using glass ionomer cement .The apical 4 mm of the apex was exposed and photo was taken and the distance from file tip to the major foramen was measured by calibrating metal ruler on graph paper. The results were statistically analyzed using ANOVA and Scheffe test at p < 0.05 level. Results: Mean distance from file tip to major foramen was 0.308 mm in Tip foramen group (I), 0.519 mm in Lateral foramen group (II) and 0.932 mm in open apex group (III). Root ZX located apical constriction accurately within ${\pm}0.5mm$ in group I of 85.71%, in group II of 59.09%, and in group III of 33.33%. There was a statistically significant difference between group I and III (p < 0.05). Conclusion: Root ZX located apical constriction accurately regardless of location of major foramen. However, Root ZX couldn't find it in open apex. Clinicians have to use a combination of methods to determine an appropriate working length at open apex. It may be more successful than relying on just electronic apex locator.

• 한국과학교육학회지
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• 제32권9호
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• pp.1417-1426
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• 2012

The purpose of this study was to analyze elementary school students' understanding of the human body by drawing the human organism. Data was gathered by open questionnaires of drawing for human body. The open questionnaire was taken with 530 elementary school students from 3rd to 6th grade. The results were as following: First, elementary school students show the highest understanding of the skeletal system, the digestive systems, the respiratory systems, the circulating system and the muscular system respectively. Second, elementary school students' understanding of the human body improved as the grade goes up. Third, it seems that elementary school students have had their own knowledge about the human body through environmental surroundings before learning about the human body.