• 한국초전도ㆍ저온공학회논문지
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• 제17권2호
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• pp.31-35
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• 2015

Mapping is a useful tool in the magnetic field analysis and design. In some specific research area, such as the nuclear magnetic resonance (NMR) or the magnetic resonance imaging (MRI), it is important to map the magnetic field in the interesting space with high accuracy. In this paper, an indirect mapping method in the center volume of an air-core solenoid is presented, based on the solution of the Laplace's equation for the field. Through the mathematical analysis on the mapping calculation, we know that the condition number of the matrix, generated by the measurement points, can greatly affect the error of mapping result. Two different arrangement methods of the measurement points in field mapping are described in this paper: helical cylindrical line (HCL) method and parallel cylindrical line (PCL) method. According to the condition number, the HCL method is recommended to measure the field components using one probe. As a simple example, we mapped the magnetic fields in a MRI main magnet system. Comparing the results in the different methods, it is feasible and convenient to apply the condition number to reduce the error in the field mapping calculation. Finally, some guidelines were presented for the magnetic field mapping in the center volume of the air-core solenoid.

• 한국정보과학회논문지:소프트웨어및응용
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• 제33권1호
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• pp.114-129
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• 2006

유사한 지식구조의 분산된 온톨로지들을 통합 및 연결하여 새로운 온톨로지를 생성하거나 확장 지식 검색을 효과적으로 제공하기 위해서는 온톨로지 모델 자체의 구조적 특성이나 제약조건을 고려한 온톨초지 매핑이 중요하다. 그러나 과거의 온톨로지 매핑은 범용성을 높이기 위해 대부분 그래프 모델을 기반으로 노드와 간선 중심의 매핑여부를 계산함으로써 온톨로지 모델의 특성과 제약조건을 매핑에 반영하지 못하는 문제점을 가진다. 본 논문에서는 RDF와 함께 온톨로지 모델로 사용되고 있는 토픽맵의 구문적 특성과 제약조건을 반영한 다중 매핑 전략의 토픽맵 매핑 기법을 제안한다. 다중 매핑 전략에는 토픽명 기반 매핑, 토픽 속성 기반 매핑, 계층 구조 기반 매핑, 연관관계 기반 매핑의 4가지 매핑 전략이 포함되어 있으며 개체들 사이의 매핑 여부를 결정하기 위해 각 매핑의 개별 유사도를 조합한 다음 단일 유사도를 결정하는 하이브리드 방식을 사용한다. 또한 토픽맵의 구문적 특성에 따라 매핑 계산 전에 매핑이 불가능한 개체들을 미리 제거함으로써 탐색 범위를 줄이고 있으며 토픽명 색인과 PSI 색인을 생성하여 매핑 계산의 효율을 높이고 있다. 제안하는 토픽맵 매핑 기법의 성능을 보이기 위해 동, 서양 철학 온톨로지들과 야후 철학 백과사전 및 독일 문학 백과사전을 토픽맵으로 구현하여 실험 데이타로 활용하였으며 그 결과 자동 생성된 매핑 집합이 전문가에 의해 생성된 매핑 집합을 대부분 포함함을 확인하였다.

• 한국과학교육학회지
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• 제28권4호
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• pp.340-349
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• 2008

이 연구에서는 비유를 사용한 반응 속도 개념 학습에서 유발되는 학생들의 대응 오류를 조사하고, 비유 표현 방식에 따라 비교하였다. 고등학교 1학년 학생 418명을 '농도와 반응 속도' 및 '온도와 반응 속도'의 목표 개념과 비유물의 글 또는 글과 그림 형태의 표현방식에 따라 4집단으로 배치하였다. 각 집단에 해당하는 비유 수업을 한 후, 대응 관계 이해도 검사를 실시하였다. 연구 결과, 과잉 대응, 인위적 대응, 대응 불이행, 무분별한 대응, 부적절한 대응, 표면적 속성 대응, 비유물 속성 보유, 불가능한 대응의 8가지 대응 오류 유형이 나타났다. 또한, 비유 표현 방식과 목표 개념의 속성에 따라 학생들이 범하는 대응 오류 유형의 빈도가 다른 양상을 보였다. 이에 대한 교육학적 함의를 논의하였다.

• Journal of applied mathematics & informatics
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• 제26권3_4호
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• pp.757-766
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• 2008

We define and characterize a fuzzy pairwise $\gamma$-irresolute open mapping (fuzzy pairwise $\gamma$-irresolute closed mapping) on a fuzzy bitopological space. We also characterize a fuzzy pairwise $\gamma$-irresolute homeomorphism on a fuzzy bitopological space.

• Journal of Computing Science and Engineering
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• 제2권1호
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• pp.44-73
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• 2008

There is general agreement that the problem of data semantics has to be addressed for XML data to become machine-processable. This problem can be tackled by defining a semantic mapping between an XML schema and an ontology. Unfortunately, creating such mappings is a tedious, time-consuming, and error-prone task. To alleviate this problem, we present a solution that heuristically discovers semantic mappings between XML schemas and ontologies. The solution takes as input an initial set of simple correspondences between element attributes in an XML schema and class attributes in an ontology, and then generates a set of mapping formulas. Once such a mapping is created, it is important and necessary to maintain the consistency of the mapping when the associated XML schema and ontology evolve. In this paper, we first offer a mapping formalism to represent semantic mappings. Second, we present our heuristic mapping discovery algorithm. Third, we show through an empirical study that considerable effort can be saved when discovering complex mappings by using our prototype tool. Finally, we propose a mapping maintenance plan dealing with schema evolution. Our study provides a set of effective solutions for building sustainable semantic integration systems for XML data.

• 한국측량학회지
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• 제31권6_2호
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• pp.593-599
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• 2013

China's Mapping Satellite-1, developed by the China Aerospace Science and Technology Corporation (CASC), was launched in three years ago. The data from Mapping Satellite-1 are able to use for efficient surveying and geometric mapping application field. In this paper, we fuse the panchromatic and multispectral images of Changchun area, which are obtained from the Mapping Satellite-1, the one that is the Chinese first transmission-type three-dimensional mapping satellite. The four traditional image fusion methods, which are HPF, Mod.IHS, Panshar and wavelet transform, were used to approach for effectively fusing Mapping Satellite-1 remote sensing data. Subsequently we assess the results with some commonly used methods, which are known a subjective qualitative evaluation and quantitative statistical analysis approach. Consequently, we found that the wavelet transform remote sensing image fusion is the optimal in the degree of distortion, the ability of performance of details and image information availability among four methods. To further understand the optimal methods to fuse Mapping Satellite-1 images, an additional study is necessary.

• 한국컴퓨터정보학회논문지
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• 제22권7호
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• pp.1-7
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• 2017

As the capacity of NAND flash module increases, the amount of RAM increases for caching and maintaining the FTL mapping information. In order to reduce the amount of mapping information managed in the RAM, a demand-based address mapping method stores the entire mapping information in the flash and some valid mapping information in the form of cache in the RAM so that the RAM can be used efficiently. However, when cache miss occurs, it is necessary to read the mapping information recorded in the flash, so overhead occurs to translate the address. If the RAM space is not enough, the cache hit ratio decreases, resulting in greater overhead. In this paper, we propose a method using two tables called TPMT(Translation Page Mapping Table) and SMT(Segmented Translation Page Mapping Table) to utilize both temporal locality and spatial locality more efficiently. A performance evaluation shows that this method can improve the cache hit ratio by up to 30% and reduces the extra translation operations by up to 72%, compared to the TPM scheme.

• 산업공학
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• 제22권1호
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• pp.17-25
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• 2009

In mobile device's user interface, menu organization is very important as well as menu structure because small display of mobile device. Menu items should be organized based on user knowledge structure to design user-centered interface. Traditionally, MDS (Multidimensional Scaling) have been most often used to expose users' perceived organization of menu items. But, information that MDS reveals is just relative spatial location of concepts and not relevant to concepts connection. Unlike MDS, Trajectory Mapping explicitly finds users' cognitive links between perceived concepts. This study proposes a Trajectory Mapping technique for eliciting knowledge structure, especially a set of cognitive pathways linking menu items, from end user. With twelve participants, MDS and Trajectory Mapping were conducted using cellular phone's menu items. And user knowledge structure was analyzed through Visual Concept Map that combination of results of MDS and Trajectory Mapping. After then, menu items were organized according to users' perceived organization. Empirical usability test was also conducted. The results of usability test showed that usability, in terms of task performance time, number of errors, and satisfaction, for newly organized interface was significantly improved compare to original interface. The methodology of this study is expected to be applicable to design a user-centered interface. In other words, Trajectory Mapping technique can be used as a design tool of user interface for imposing user knowledge structure on the interface.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제15권12호
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• pp.918-922
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• 2009

본 논문에서는 참조 패턴에 따라 페이지 사상 정책과 블록 사상 정책을 선택적으로 사용하는 Janus-FTL을 제안한다. 일반적으로 플래시 메모리의 특성에 따르면, 순차 참조의 경우 블록 사상 FTL이 적당하고, 비 순차적인 참조의 경우 페이지 사상 FTL이 적당하다. 따라서 실용적인 FTL은 데이터의 특성에 따라 플래시 메모리 블록을 블록 사상 또는 페이지 사상 정책으로 선택적으로 사용하면서, 블록 사상 영역과 페이지 사상 영역의 크기를 참조 패턴에 따라 효율적으로 변화하여 할당하는 관리 기법이 필요하다. 본 논문에서는 저장된 데이터가 블록 사상 영역에서 페이지 사상 영역으로 이동하는 퓨전(Fusion) 연산과 반대로 이동하는 디퓨전(Defusion) 연산을 통해, 블록 사상과 페이지 사상 기법을 동시에 활용하는 Janus-FTL을 설명한다. 또한 Janus-FTL을 구현하여 성능을 측정하였으면, 성능 측정 결과에 따르면 기존의 FTL에 비해 최대 50%의 우수한 성능을 보였다.

• 한국정밀공학회지
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• 제23권5호
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• pp.30-36
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• 2006

The participants in collaborative environment want to get the right information or documents which are intended to find. In general search systems, documents which contain only the keywords are retrieved. For searching different word-expressions for the same meaning, we perform mapping before searching. Our mapping-based search approach has two parts, ontology-based mapping logic and ontology libraries. The ontology-based mapping consists of three steps such as character matching (CM), definition comparing (DC) and similarity checking (SC). First, the character matching is the mapping of two terminologies that have identical character strings. Second, the definition comparing is the method that compares two terminologies' ontological definitions. Third, the similarity checking pairs two terminologies which were not mapped by two prior steps through evaluating the similarity of the ontological definitions. For the ontology libraries, document ontology library (DOL), keyword ontology library (KOL), and mapping result library (MRL) are defined. With these three libraries and three mapping steps, an ontology-based search engine (OntSE) is built, and a use case scenario is discussed to show the applicability.