• Journal of Elementary Mathematics Education in Korea
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• v.22 no.4
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• pp.331-368
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• 2018

This study is derived from a student who can add without knowing the addition principle. To understand where the student's response come from, we came to analyse the curriculum contents of natural numbers, decimals and fractions addition principle. At the same time, we surveyed two different school of forty six sixth grade participants with questionnaires to determine whether it is a problem of the student or an universal one. As a result, we found that there is a room for improvement in the addition and connections of addition. We propose appropriate instructional method regarding connections of addition and addition principle of natural numbers, decimals and fractions. The conclude there is a close relation and differences among the principles of natural numbers, decimals and fractions in the proposed instructional method. Therefore, we need to consider and instruct the differences of the number expansion.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.451-455
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• 2012

Asymptotic analysis is a powerful tool for the mathematically rigorous design and analysis of anisotropic beam structures. However, it has a limitation in that the asymptotic approach requires asymptotically correct boundary conditions for higher-order solutions, which are often needed for beams weak in shear. A method utilizing Saint-Venant's principle was proposed in a previous work to improve the stress state of isotropic beams and plates. In this paper, such a method is generalized for anisotropic beams, so that one does not need to consider the asymptotically correct boundary conditions for higher-order solutions. Consequently, solving the recursive system equations is not necessary, which makes the method very efficient in terms of accuracy and computational effort.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.7
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• pp.669-676
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• 2003

In this paper, a novel design method for an ultra-wide band TEM horn antenna is proposed on the basis of parallel plate waveguide theory. A principle of TEM modes generation is analyzed and the characteristics of this antenna are experimentally investigated. The proposed TEM horn antenna has an exponentially tapered structure to increase matching bandwidth. Also, the designed TEM horn has shortened length but increased aperture so that the bandwidth for cutoff frequency is increased. The measured result show that the proposed TEM hem antenna has the frequency band of 75 MHz to 1200 MHz for VSWR less than 2.0 and the bandwidth of the TEM horn becomes more than twice comparing to that of a linearly tapered TEM hem. It is anticipated that the manufactured antenna is applicable to UWB systems for impulse response measurement.

• Asia Marketing Journal
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• v.7 no.2
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• pp.93-121
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• 2005

This study is about to enhance our understanding of market and market principle, so that marketing research contribute to create more values for customers and firms. For this purpose three following suggestions are proposed. First, marketing research should expand its research scope to include all the market participants in addition to consumers. Second, marketing research should expand into the 'internal market' of the organization. where internal sub-groups are engaging in fierce marketing-like activities. Third, marketing researchers should thoroughly understand the basic market principles and the macro political-economic structure of capitalism. Only on the ethical basis of free market system, it is argued, market, marketing, and marketing research will flourish.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.82-84
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• 2003

위치 기반 서비스 시스템은 이동객체에 대한 효율적인 검색을 가능하게 해주는 시스템으로 이동객체의 현재와 과거 위치에 대한 정보를 유지한다. 이러한 시스템을 평가하기 위해서는 이동객체들의 사실적인 움직임을 기술한 데이타 집합이 필요하다. 이러한 데이타 집합을 생성하는 대표적인 생성기로는 GSTD가 있다. 하지만 GSTD도 몇 가지 문제점을 지니고 있다. GSTD에 의해서 생성되는 작업공간과 데이타 집합은 실생활 객체의 움직임을 묘사하는데 부적절한 면이 있다. 또한 GSTD가 제공하는 매개변수 안에 사용자가 객체의 이동성과 시간성을 명확히 기술 해줄 수 있는 부분이 제시 되어 있지 않다. 본 논문에서는 GSTD의 여러 매개변수들과 함수들을 변환하거나 추가하여 좀 더 현실적인 객체 움직임을 나타내는 데이타 집합을 만들고, 사용자가 객체의 특성을 세밀히 지정해 줄 수 있는 확장된 GSTD를 구현한다. 또한 확장된 GSTD 기반 LBS 시뮬레이터의 설계와 구현에 관한 원리를 포함한 주요 특징을 기술한다. 확장된 GSTD는 다양한 LBS 응용 시스템의 성능 측정에 활용될 수 있을 것이다.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.909-915
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• 2004

This paper suggests an evaluation of risk level for damage of marine accidents in SRRs. Qualitative analyses in words is sometimes priorior to quantative analyses in numeric symbols. This paper introduces a concept of fuzzy theory with the plenty of related literature riview and AHP in the Korean SRRs of RCC and RSC. The methodology of this paper is $max{\cdot}min$ composition of fuzzy extensive principle, defuzzifiation is centroid of gravity methods. At the result, the evaluation of risk level is especially over Serious for marine accident of Busan SRRs. This paper recommends that many Rescue Vessels and Equipments need to the reduction of risk level about those.

• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.83-88
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• 2004

This paper suggests on evaluation of risk level for damage of marine accidents in SRRs. This paper intoduces a concept of fuzzy logic with the plenty of related literature riview, fuzzy measure t-seminormed fuzzy integral and in the Korean. SRRs of RCC and RSC. The methodology of this paper is max$\cdot$min composition of fuzzy extensive principle, defuzzifiation is centroid of gravity methods. And final evaluation value using t-seminormed fuzzy integral. At the result, the evaluation of risk level is especially over Serious for marine accident of Mokpo, Tongyoung, Busan SRRs. This paper recommends tint many Rescue Vessels and Equipments need to the reduction of risk level about those.

• Journal of the Korea Society of Computer and Information
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• v.9 no.4 s.32
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• pp.5-12
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• 2004

The data transformation between XML and Relation Database is made through the Principle of mapping bewtween them. There are two ways to access SQL Server, one is to assign SQL query to URL and the other is to use template file. MS-SQL server takes advantage of OpenXML function to transform the results of executing SQL query into XML documents. That is, OpenXML first makes node tree and then transforms row set data of XML documents into XML data of relation type. In order to insert XML data into database data. data is extracted from parsing XML documents using sp_xml_preparedocument procedure, and then the document structure is mapped into tree structure and stored in a table of database. Consequently, Data transformation between XML and Relation Database is made through mapping bewtween them. This article proposes the principle of mapping between XML and Relation Database and then shows the implementation of transformation between them so that it introduces the possibilty of bringing the extension and efficiency of data and various effects.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.4
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• pp.77-82
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• 2017

As frequencies increase to the millimeter wave bands the cross sections of wave guides become smaller than a few millimeters, which cause sapatial problems in realization of spatial combining power amplifiers. In this paper we intented to overcome the problem by widening the width of wave guides using horn antenna principles. We designed a widened rectangular wave guide for using in spatial combining power amplifier in 60GHz ISM band(57-64GHz), and we installed Antipodal transition in the widened wave guide, and then we characterized it as a spatial combining power amplifier. For the compatibility of WR15 standard wave guide, we widened the width of WR15 to 7mm using principle of H-plane sectoral horn antenna and then installed 3 slots of back to back Antipodal transition. The designed spatial combining power amplifier showed good characteristics of return loss less than -22.4dB and insertion loss less than 0.53dB. However, as widening the width of the wave guide, additional modes such as $TE_{20}$, $TE_{30}$ in addition to $TE_{10}$ were accurred in the bandwidth of WR15, which restricted the bandwidth and widening of the width of the wave guide.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.242-245
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• 2020

최근 IT 기술의 발전에 따라 블록체인 기술과 융합하려는 다양한 시도를 보인다. 비트코인(Bitcoin)의 탄생으로 알려지게 된 블록체인은 P2P (Peer-to-Peer) 네트워크에서 데이터의 무결성 조건을 만족할 수 있게 되면서 보안 기술에 대해 많은 연구가 진행 중이다. 데이터의 무결성을 증명하기 위해 합의 알고리즘을 사용하는데 합의 알고리즘의 처리속도 및 저장 공간 문제 등으로 인해 다른 분야로 확장에 어려움을 겪고 있다. 따라서 블록체인을 구성하는 환경이나 목표에 따라서 적절한 합의 알고리즘을 선택하는 것이 중요하다. 본 논문에서는 확장성 문제를 해결할 수 있는 Bitcoin-NG 합의 알고리즘을 비롯하여 다양한 합의 알고리즘의 원리와 장단점을 소개한다. 블록의 합의에 참여하는 범위, 리더를 선정하는 방법 등의 기준으로 Bitcoin-NG 알고리즘이 확장성 문제에 긍정적인 합의 알고리즘으로서 갖춘 특징을 살펴 보고 앞으로 합의 알고리즘의 발전 방향에 대해 고찰한다.