• Journal of The Korean Association For Science Education
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• v.35 no.1
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• pp.27-35
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• 2015

General education is changed by accepting the change in education environment to digital generation, emphasis about student-centered education, and change of teacher's role. E-learning has taken center stage as an effective learning environment but the problems are drawn for the absence of interaction that is important in learning. In this study, on the basis of questionnaire results about learning using website, we operated blended-learning where students come and go in cyberspace and physical space to set up the lesson environment for emphasizing interaction. We selected a control group (N=40) and an experimental group (N=40) from second grade students in a middle school for this research. General instructor-led lessons were implemented in the control group and blended-learning lessons to emphasize interaction between teacher and students were implemented in the experimental group. The experiments were applied to eight class-hours in 'characteristics of matter' unit. We implemented Test of Science Related Attitude (TOSRA) to the students before and after the lessons and administered questionnaire for checking attitude changes and perception in students. The results of the test show that the experimental group students were more encouraged and became more confident and curious about scientific learning than the control group students. The analysis of the interview and results of TOSRA show that blended-learning provided guidance and feedback by the teacher to the experimental group students more than the control group students. Blended-learning is suggested as a learning-method that is helpful in improving scientific attitude in students because it enables them to express their experiences without limit of time-space and promote interaction between teacher and students.

• Journal of the Korea Society of Computer and Information
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• v.6 no.1
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• pp.45-50
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• 2001

Congestion may take place in the ATM network because of high-speed cell transmission features, and cell delay and loss also can be caused by unexpected traffic variation. Thus. traffic control mechanisms are needed. One of them to decrease congestion is the cell shaping. This paper proposes a hybrid type cell shaper composed of a Leaky Bucket with token pool, EWMA with time window, and a spacing control buffer. The simulator BONeS with the ON/OFF traffic source model evaluates the performance of the proposed cell shaping method. Simulation results show that the cell shaping concerning the respective source traffics is adapted to and then controlled on the mean bit rate.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.370-374
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• 1999

The proposed algorithm used the Hybrid teaming rule in the input and hidden layer, and Back-Propagation teaming rule in the hidden and output layer. From the results of simulation of tracking control with one link manipulator as a plant, we verify the usefulness of the proposed control method to compare with common direct adaptive neural network control method; proposed hybrid teaming rule showed faster loaming time faster settling time than the direct adaptive neural network using Back-propagation algorithm. Usefulness of the proposed control method is that it is faster the learning time and settling time than common direct adaptive neural network control method.

• Journal of Korea Multimedia Society
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• v.16 no.4
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• pp.418-429
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• 2013

This paper presents a GIS vector map data compression scheme based on hybrid polyline simplification method and SEC(spatial energy compaction). The proposed method extracts all layers which contain polylines in the GIS vector map and compress all polylines in extracted layers by the hybrid polyline simplification and SEC based on MAE(minimum area error) for each segment in the line. The proposed simplification and SEC increase the compression ratio while preserving the shape quality. We analyze the visual aspects and compression efficiency between the original GIS vector map and the compressed map. From experimental results, we verify that our method has the higher compression efficiency and visual quality than conventional methods.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.2
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• pp.46-53
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• 2005

We have analyzed the temperature and humidity aging test results of a composite solid propellant. The temperature aging test was performed to evaluate the storage life of a propellant, while the humidity aging test could provide the hygroscopicity of Ammonium Perchlorate(AP) exposed to .elative humidity (RH) 10, 30, $50\%$ environment. A specimen was used in the temperature test, and a block of propellant from the actual motor was used in the humidity test. We report that the 4-month storing at 60 degree is equivalent to the 10-year 60 degree condition. The composite solid propellant with HTPB binder showed signs of hardening with time lapse but the effect of humidity up to RH $50\%$ was not noticeable.

• 한국벤처창업학회:학술대회논문집
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• 2017.04a
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• pp.25-25
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• 2017

전국에 1,000여개의 다문화 기관들이 활동 중이다. 그중 정부주도형인 여성가족부 지정 다문화가족지원센터 210여 곳을 제외한 나머지 기관들은 대부분 정부 민간 혼합형이거나 민간주도형 기관들이다. 정부주도형 기관들은 중앙정부와 지방자치단체로부터 운영비가 지원되지만 정부 민간 혼합형이나 민간주도형 기관들은 운영비를 기부금 또는 후원금에 의존한다. 그러나 경제위기의 도래로 기부금이나 후원금이 급감하는 상황에서 정부 민간 혼합형이나 민간주도형 기관들의 자립은 더욱더 어려워질 전망이다. 이러한 전망과는 달리, 지원 대상들과 다문화이슈는 지금보다 훨씬 더 늘어날 전망이다. 국내 이주민의 수는 매년 증가추세이다. 향후 2050년이 되면 전체인구의 10%가 외국인이라는 전망도 나온다. 외국인의 정주화 그리고 가족이민 증가에 따른 상이한 종교와 문화에 대한 편견 없는 이해와 대화가 강조될 것이며, 학교교육정책, 직업양성, 노동시장정책, 동등한 노동조건과 사회보장 요구, 사회적 차별에 대한 계몽정책 등 다양한 다문화 이슈도 부각될 것이다. 이처럼 다양한 분야에서 다문화 이슈를 가장 잘 다룰 수 있는 민간주도형 다문화기관의 자립 여부는 다문화 지원정책의 성패와도 연결된다고 볼 수 있다. 결국 민간주도형 다문화기관이 지금의 운영구조를 개선하고 재정적 자립을 확보하기 위해서는 다문화 관련 비즈니스모델 개발을 통해 다문화 기관들이 스스로 자립할 수 있는 사회적기업에 관심을 가질 수밖에 없다. 사천다문화통합지원센터는 비영리민간단체로 지난 13년 동안 창조적인 다문화 사업들을 추진하여 괄목할만한 성과를 거두었다. 그러나 일반 기부금이나 후원금으로 운영비를 충당하고 있는 상황에서 자립 기반 구축을 위한 비즈니스 모델 개발은 필수적이었다. 마침내 요리조리아시아 협동조합을 만들어 청소년 공정여행 프로그램인 세계로여행학교와 아열대채소 농장을 운영중에 있다. 뿐만 아니라 기업의 CSR(Corporate Social Responsibility) 해외공헌사업도 위탁받아 운영하고 있다. 본 연구에서는 사천다문화통합지원센터가 그동안 진행해 온 청소년 공정여행과 아열대채소 농장을 다문화기관의 비즈니스 모델적 측면에서 사례 분석한 후, 벤치마킹을 통해 민간주도형 다문화기관들로 확대시킴으로써 사회혁신의 기회를 증대시킬 방안을 제시하였다.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.138-142
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• 2007

본 연구는 고점도 유체의 혼합을 위한 교반기 설계의 기초연구로서 스크류 형상의 임펠러(또는 헬리컬 임펠러)를 가지는 교반기 내의 유동과 이에 따른 유체혼합 특성을 수치해석을 통해 가시화한 것이다. 이와 더불어 양호한 혼합효과를 가져다 줄 것으로 예상되는 엇갈림형 스크류 임펠러의 모델을 제안하였다. 수치해석상의 유체는 고점도의 Newton유체로 가정하였으며 임펠러의 회전속도는 6[rpm]으로 아주 작게 하여 저 레이놀즈수(약 Re=3)에서 혼합효과를 연구하였다. 또한 각종 설계 파라미터를 변화시켜 혼합 양상의 차이를 분석하여 설계에 반영하고자 하였다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.1
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• pp.19-27
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• 2017

The objective of this study was to determine the growth characteristics of cool (C1) and warm season grasses (C2) in pastures mixed with C1 and C2 at an altitude of 400 m in Jeju island to establishing pasture suitable for grazing horses and to evaluate the effect of pastures mixed with tall and short type grasses on the intake characteristics of horses. C1 used in this study was Kentucky bluegrass, redtop (short type grass) and tall type grasses were orchardgrass and tall fescue, respectively. Treatments of this study were consisted of four groups and the short type grass used in pastures mixed with C1 and C2 was mainly bermudagrass. Four treatment groups were follow as; Treatment 1 (bermudagrass + Kentucky bluegrass + redtop) 2) Treatment 2 (bermudagrass + tall fescue + orchardgrass) 3) Treatment 3 (Kentucky bluegrass + redtop) 4) Treatment 4 (tall fescue + orchardgrass). Bermudagrass was a little winter killing and inhibition of plant growth at an altitude of 400 m. Plant heights in pastures mixed with C1 and C2 were grown better than that in pastures mixed with C1. Especially, plant height in Treatment 4 was higher than other treatments. Dry matter yield was in the following order: Treatment 4> Treatment 3> Treatment 2> Treatment 1. Dry matter yield in pastures mixed with C1 increased as compared with pastures mixed with C1 and C2. Dry matter yield in Treatment 3 was higher than other treatments. In the first investigation regarding vegetation distribution, bermudagrass ratios among grasses in Treatment 1 and Treatment 2 were 11.7 and 13.3%, respectively. The growth of bermudagrass in winter was low due to the cold damage. However the growth of Kentucky bluegrass, redtop, tall fescue and orchardgrass was good. In the second investigation, bermudagrass ratios among grasses in Treatment 1 and Treatment 2 were 5.0 and 11.7%, respectively. Growth of forage in the second investigation was poor as compared to the first investigation. nutritive values(crude protein content, neutral detergent fiber content, acid detergent fiber content, digestibility) were good in pastures mixed with C1 Especially, nutritive values in pastures mixed with tall was higher than those of pastures mixed short grasses. P content among minerals in Treatment 1 was higher than other groups. However, the content of Ca, Mg and Mn were lower. The contents of Ca, K, Mg, Na, Cu, Zn and Fe in Treatment 2 were higher. However, the contents of K, Mg, Na, Cu, Zn and Fe in Treatment 3 were lower. Therefore, we suggest that cool season grasses with short grasses were sowed to establishing pasture suitable for grazing horses at an altitude of 400 m in Jeju island.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.1
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• pp.49-62
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• 2024

In this paper, a sustainable closed-loop supply chain (SCLSC) network model is proposed for domestic mobile phone industry. Economic, environmental and social factors are respectively considered for reinforcing the sustainability of the SCLSC network model. These three factors aim at minimizing total cost, minimizing total amount of CO₂ emission, and maximizing total social influence resulting from the establishment and operation of facilities at each stage of the SCLSC network model. Since they are used as each objective function in modeling, the SCLSC network model can be a multi-objective optimization problem. A mathematical formulation is used for representing the SCLSC network model and a hybrid meta-heuristic approach is proposed for efficiently solving it. In numerical experiment, the performance of the proposed hybrid meta-heuristic approach is compared with those of conventional meta-heuristic approaches using some scales of the SCLSC network model. Experimental results shows that the proposed hybrid meta-heuristic approach outperforms conventional meta-heuristic approaches.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.685-687
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• 2002

오늘날 인터넷 활용이 본격적으로 대중화되면서 교육현장에서도 웹을 기반으로 한 다양한 교육방법이 연구, 개발되어 WBI 학습, 웹 기반 CAI, 원격강의 등의 가상교육으로 발전되어 왔다. 웹 기반 교육이 교실수업에 비해 가지는 장점을 최대한 살려서 현실성 있고 효율적인 교육의 효과를 얻으려면 학습자의 능력과 관심 , 흥미 , 적성 등을 고려한 웹 기반 수업 모형 개발이 요구된다. 본 논문은 제7차 교육과정에서 실시되는 단계형 수준별 교육과정에 심화보충형을 혼합한 수준별 수업모형을 웹 기반 수업모형으로 제시하고자 한다. 웹을 기반으로 한 혼합형 수준별 수업이 가능해짐으로써 교수자는 웹 데이터베이스를 통해 학습의 촉매자, 조언자로서의 역할을 할 수 있으며, 학습자는 학업 성취수준에 알맞은 학습 구성이 가능해짐으로써 보다 효과적인 자기주도적인 학습이 이루어질 것으로 기대된다