• 구강회복응용과학지
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• 제18권3호
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• pp.157-170
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• 2002

IPS Empress 2의 산 부식 후 표면 처리재와 레진 시멘트 종류에 따른 전단 결합 강도를 비교 분석하기 위해서 실란 처리, 실리카 코팅 그리고 Targis link 처리군으로 분류하고 Panavia F, Variolink II와 Rely-X ARC 레진 시멘트 세종류를 이용해서 9개군에 각 군당 30개의 시편을 제작하였다. 그리고 구강환경에서의 변화를 알아보기 위해서 구강환경과 유사한 조건으로 $37^{\circ}C$ 증류수에서 24시간 수중침지, $37^{\circ}C$ 증류수에서 5주간 수중 침지, 그리고 5주간 수중침지 중 매주 2000회씩 10,000회의 열 순환을 한 다음 각 시편의 전단결합강도를 측정하고 파절면을 주사 전자현미경으로 관찰하여 다음과 같은 결론을 얻었다. 1. 표면처리에 따른 전단결합강도는 모든 군에서 유의한 차이를 보였다. 실란 처리, 실리카 코팅, 그리고 Targis link의 순으로 유의한 결합력의 감소를 보였다(p<0.001). 2. 레진 시멘트의 종류에 따른 차이를 비교한 결과에서 Targis link 도포한 군만 제외하고 나머지 군에서는 레진 시멘트의 종류에 따른 결합강도의 차이를 보였다(p<0.05). 3. 수중 침지 시간에 따른 전단 결합강도는 모든 군에서 유의한 차이를 보이지는 않았지만 실란을 처리 후 Panavia를 사용한 군, 실리카 코팅 처리 후 Variolink를 사용한 군, Targis link 처리 후 Rely-X ARC와 Variolink를 사용한 군에서는 결합력의 감소를 나타내었다(p<0.05). 4. 열 순환 시행시에는 실란과 실리카 코팅 처리후 Rely-X ARC를 사용한 군과 실리카 코팅 처리후 Panavia F를 사용한 군만 제외하고 나머지는 유의한 결합력의 감소를 보였다(p<0.05). 5. 파절 시험 후 시편에 대한 주사 전자 현미경 관찰결과 모든 군에서 복합성 파절 양상을 보였다.

• 대한전자공학회논문지TE
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• 제37권3호
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• pp.93-103
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• 2000

본 논문은 MPLS (Multiprotocol Label Switiching) 망에서 인터넷 멀티캐스트 라우팅 프로토콜을 지원하기 위한 방안을 제시한다. 인터넷 멀티캐스트 라우팅 프로토콜은 트리의 구성방식과 속성에 따라 최단거리 트리 방식, 공유트리 방식 및 복합트리 방식 등으로 분류된다. 각 방식에 따라 MPLS 망에서 지원해야 하는 기능이 달라진다. 특히, 단/양방향성 트리 링크, Flooding/prune 방식의 트리 구성, 하나의 멀티캐스트 그룹 에 다중 트리의 존재 등 여러 가지 미해결이거나 해결하기 어려운 문제점들이 존재한다. 본 논문에서는 몇가지 가정을 세우고, 이를 바탕으로 각 멀티캐스트 라우팅 프로토콜을 MPLS 망에서 지원하기 위한 방안을 제시한다. Flooding/prune 방식의 멀티캐스트 라우팅 프로토콜에 대해서는 새로이 브로드 캐스팅용의 레이블 을 정의하여 해결하고, 공유트리 방식에 대해서는 기 제안된 블록기반 멀티캐스트 전송기법을 도입하여 셀인터리빙 (Cell Interleaving) 문제를 해결하며, 마지막으로 복합트리 방식에 대해서는 기존 멀티캐스트 라우팅 프로토콜에 기능을 추가하므로써 MPLS 지원문제를 간단히 해결한다.

• 대한토목학회논문집
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• 제35권5호
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• pp.1173-1177
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• 2015

본 논문에서는 도시철도역사 내 철도안전사상사고의 사고유형과 원인분류를 표준화하는 방안을 제시하였다. 이를 위하여 도시철도 운영기관 (서울메트로, 서울도시철도공사)의 4,086건 철도안전사상 사고를 분석하여 표준화 코드를 작성하였다. 사고유형의 표준화는 사상자유형, 사고대상, 사고 위치, 사고형태로 구분하여 분류하고 이를 포함한 4자리의 표준화코드를 제시하였다. 사고원인의 표준화는 원인제공자, 음주여부, 1차 원인, 2차 원인을 포함한 4자리의 표준화코드를 제시하였다. 이러한 표준화코드는 도시철도 역사 내 철도안전사상사고의 체계적인 비상관리 및 긴급대응에 기본이 되는 역할을 담당할 것이라 판단된다.

• 정보처리학회논문지C
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• 제10C권1호
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• pp.77-86
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• 2003

본 논문은 MPLS(Multiprotocol Label Swtiching) 망에서 인터넷 멀티캐스트 라우팅 프로토콜을 지원하기 위한 방안을 제시한다. 인터넷 멀티캐스트 라우팅 프로토콜은 트리의 구성방식과 속성에 따라 최단거리트리 방식, 공유트리 방식 및 복합트리 방식 등으로 분류된다. 각 방식에 따라 MPLS 망에서 지원해야 하는 기능이 달라진다. 특히, 단/양방향성 트리 링크, Flooding/Prune 방식의 트리 구성, 하나의 멀티캐스트 그룹에 다중 트리의 존재 등 여러 가지 미해결이거나 해결하기 어려운 문제점들이 존재한다. 본 논문에서는 몇가지 가정을 세우고, 이를 바탕으로 각 멀티캐스트 라우팅 프로토콜을 MPLS 망에서 지원하기 위한 방안을 제시한다. Flooding/Prune 방식의 멀티캐스트 라우팅 프로토콜에 대해서는 새로이 브로드캐스팅용의 레이블을 정의하여 해결하고, 공유트리 방식에 대해서는 기 제안된 블록기반 멀티캐스트 전송기법을 도입하여 셀 인터리빙(Call Interleaving) 문제를 해결하며, 마지막으로 복합트리 방식에 대해서는 기존 멀티캐스트 라우팅 프로토콜에 수정된 SPT 전환 기능을 추가하므로써 MPLS 지원문제를 해결한다. 제안하는 방법이 기존의 방법보다 비교해 보았을 때 전송지연에서 우수한 성능을 보임을 모의 실험을 통해서 확인하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1365-1375
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• 2009

The types and quantities of Hazmat and Hazmat transport are gradually increasing, keeping pace with industrialization and urbanization. There are currently more than 1,000 types of Hazmat,, and new types are added every year. At present the safety management for Hazmat transport only considers reducing accident probability, but even when an accident involving Hazmat-carrying vehicles occurs, that is not regarded as a Hazmat-related accident if the Hazmats do not leak out from the containers carrying them. Based on this principle, in turn., the methods to reduce risk (Risk=Probability$\times$Consequence) have to be developed by incorporating accident probability and consequence. By using Geographic Information System (GIS), a technical method was invented and is automatically able to evaluate the consequence by different types of Hazmat. Thus this study analyzed the degree of risk on the links classified by the Hazmat transport pathways. In order to mitigate the degree of risk, a method of 7-step risk management in transporting Hazmat on railway industries was suggested. The 7-step risk management is definded as the following: 1st step: buliding up GIS DB, 2nd step: calculating accident probability on each link, 3rd step: calculating consequence by Hazmat types, 4th step: determination of risk, 5th step: analysis of alternative plans for mitigating the risk, 6th: measure of effectiveness against each alternative, and 7th step: action plans to be weak probability and consequence by the range recommended from ALARP. In conclusion., those 7 steps are recommended as a standardization method in this study.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제2권1호
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• pp.3-13
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• 1998

In mathematics education we have focused on how to improve the problem-solving ability, which makes its way to the new direction with the introduction of meta-cognition. As meta-cognition is based on cognitive activity of learners and concerned about internal properties, we may find a more effective way to generate learners problem-solving power. Its means that learners can regulate cognitive process according to their gorls of learning by themselves. Moreover, they are expected to make active participation through this process. If specific meta problems designed to develop meta-cognition are offered, learners are able to work alone by means of their own cognition and regulation while solving problems. They can transfer meta-cognition to the other subjects as well as mathematics. The studies on meta-cognition conducted so far may be divided into these three types. First in Flavell(［3］) meta-cognition is defined as the matter of being conscious of one's own cognition, that is, recognizing cognition. He conducted an experiment with presschoolers and children who just entered primary school and concluded that their cognition may be described as general stage that can not link to specific situation in line with Piaget. Second, Brown(［1］, ［2］) and others argued that meta-cognition means control and regulation of one's own cognition and tried to apply such concept to classrooms. He tried to fined out the strategies used by intelligent students and teach such types of activity to other students. Third, Merleary-Ponty (1962) claimed that meta-cognition is children's way of understanding phenomena or objects. They worked on what would come out in children's cognition responding to their surrounding world. In this paper following the model of meta-cognition produced by Lester (［7］) based on such ideas, we develop types of meta-cognition. In the process of meta-cognition, the meta-cognition working for it is to be intentionally developed and to help unskilled students conduct meta-cognition. When meta-cognition is disciplined through meta problems, their problem-solving power will provide more refined methods for the given problems through autonomous meta-cognitive activity without any further meta problems.

• 산업경영시스템학회지
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• 제38권3호
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• pp.29-38
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• 2015

In this paper, scale efficiencies and relative efficiencies of R&D projects in Industrial Technology Program, sponsored by Ministry of Trade, Industry and Energy, Korea, are calculated and compared. For the process, various DEA (Data Envelopment Analysis) models are adopted as major techniques. For DEA, two stage input oriented models are utilized for calculating the efficiencies. Next, the calculated efficiencies are grouped according to their subprograms (Industrial Material, IT Fusion, Nano Fusion, Energy Resources, and Resources Technology) and recipient types (Public Enterprise, Large Enterprise, Medium Enterprise, Small Enterprise, Lab., Univ., and etc.) respectively. Then various subprograms and recipient types are compared in terms of scale efficiencies (CCR models) and relative efficiencies (BCC models). In addition, the correlation between the 1st stage relative efficiencies and the 2nd stage relative efficiencies is calculated, from which the causal relationship between them can be inferred. Statistical analysis shows that the amount of input, in general, should increase in order to be scale efficient (CCR models) regardless of the subprograms and recipient types, that the 1st and 2nd stage relative efficiencies are different in terms of the programs and recipient types (BCC models), and that there is no significant correlation between the 1st stage relative efficiencies and the 2nd stage relative efficiencies. However, the results should be used only as reference because the goal each and every subprogram has is different and the situation each and every recipient type faces is different. In addition, the causal link between the 1st stage relative efficiencies and the 2nd relative efficiencies is not considered, which, in turn, is the limitation of this paper.

• 한국수학교육학회지시리즈A:수학교육
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• 제44권4호
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• pp.627-651
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• 2005

This study was conducted to attain an in-depth understanding of students' mathematical representations and to present the educational implications for teaching them. Twelve mathematical tasks were developed according to the six types of problems. A task performance was executed to 151 third graders from four classes in DaeJeon and GyeongGi. We analyzed the types and forms of representations generated by them. Then, qualitative case studies were conducted on two small-groups of five from two classes in GyeongGi. We analyzed how individuals' representations became elaborated into group representation and what patterns emerged during the collaborative small-group learning. From the results, most students used more than one representation in solving a problem, but they were not fluent enough to link them to successful problem solving or to transfer correctly among them. Students refined their representations into more meaningful group representation through peer interaction, self-reflection, etc.. Teachers need to give students opportunities to think through, and choose from, various representations in problem solving. We also need the in-depth understanding and great insights into students' representations for teaching.

• 한국자동차공학회논문집
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• 제10권1호
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• pp.209-215
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• 2002

A study of the guideway vehicle was made for a comparison of ride stabilities between its two primary steering types; one is the front wheel steering and the other the front-rear wheel. A numerical model as a closed loop system was built for an investigation of various factors to have an influence on the vehicular critical speed which is closely associated with ridabilities. It was shown that dynamics stabilities of the front steering type was much better over a large value of steering gain and the longer distance between front axle and guide link for both types provided better stabilities as well. A large steering gain ratio of the front to the rear significantly plays an important role in an improvement of stability in the front-rear steering. To observe a qualitative trend on stability behaviors, the root locus was obtained by considering a time lag which may be frequently caused by the complicated steering mechanism. In performing so, the appropriate selection of steering gain had a greater effect on the front-rear steering vehicle far more ride comfort. In addition, the dynamics model proposed here can be utilized for a more accurate evaluation on the vehicle design in lateral or yawing absorber and moreover expanded for the analysis of independent four-wheel steering vehicle.

• 대한안전경영과학회지
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• 제12권1호
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• pp.35-42
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• 2010

Due to the industrialization and urbanization, the transport of hazardous materials increases, which rises possibilities in occurring prospective accidents in terms of hazardous material transport as well. This study applied the model developed from the previous research to analyze the scale of damage areas from the accidents related to hazardous material accidents, as well as suggested a method to measure automatically the scale of accident including casualties and environmental damage based on the guideline which suggests the quantities of hazardous materials exposed from an accident and was defined in the study of standardization for hazardous material classification. A buffering analysis technique of Geographic Information System (GIS) was applied for that. To apply the model which evaluates the scale of population and exposure to environment on each link, rail network, zones, rail accident data, rail freight trips, and locations of rivers etc were complied as a database for GIS analysis. In conclusion, a method to measure damage areas by the types of hazardous materials was introduced using a Clip and a Special Join technique for overlay analysis.