• 한국정보처리학회논문지
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• 제2권6호
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• pp.903-917
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• 1995

대부분의 데이타베이스 시스템에서, 이미지는 캡션(caption), 주석(annotation), 속성(attribute)과 같이 그 이미지와 관련된 텍스트를 이용하여 간접적으로 인덱스 되었다. 그러나, 이미지에 포함된 정보를 직접적으로 사용하여 내용에 기반한 이미 지의 저장과 검색을 지원하는 이미지 데이타베이스 시스템의 요구가 점점 증가하고 있다. 내용에 기반한 몇몇 인덱싱 방법들이 있는데 그중에서 Petrakis는 이미지를 구성하는 오브젝트들의 공간관계와 속성을 고려한 이미지 인덱싱 방법을 제안했다. 이것은'2-D string'에 기반한 인덱싱 연구의 확장인데. 이 방법은 많은 저장공간을 필요로 하며 융통성이 부족하다. 본 논문은 페이징 기법을 사용하는 kd-trr를 이용한 인덱스 화일구조를 제안한다. 그리고 정규화 과정을 사용해서 실제 이미지로부터 키를 추출하는 예를 보이고 시뮬레이션을 통해 비교하였다. 실험 결과는 제안된 방법이 훨씬 적은 저장공간을 요구하고, 융통성면에서 개선이 되었음을 보여준다.

• 대한공간정보학회지
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• 제18권2호
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• pp.113-118
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• 2010

지형정보에 대한 3차원 복원 및 지리정보에 관한 연구와 적용은 최근 국가적인 정책을 통하여 R&D 사업 및 시범 사업 등으로 여러 분야에 걸쳐 진행되고 있다. LiDAR 시스템은 3차원 공간데이터를 손쉽고 조밀하게 취득할 수 있는 이점이 있어 다방면으로 연구와 활용이 이루어지고 있으나 3차원으로 구성된 점 자료의 특성으로 볼 때 화면을 통한 2차원의 형태로 나타내기 위해서는 많은 연산 처리를 필요로 하게 되어 높은 사양의 처리 프로세서가 필요하다. 이에 비해 2차원 격자구조는 간단한 구조와 처리속도로 인하여 벡터구조에 비하여 저가의 장비에서도 가능한 장점이 있다. 따라서 본 연구에서는 3차원의 형식으로 저장된 LiDAR 자료를 도심지역의 3차원 지형 표현이나 건물 표현등에 활용하고자 할 경우 발생할 수 있는 과대한 저장공간의 요구에 따른 문제를 해소하기 위하여 3차원 지형 표현 자료로 제공하기 유용한 2차원 격자 형태의 자료로 재구성하여 그 저장공간을 축소시키면서 트리구조를 응용하여 세밀한 표현도 가능하도록 하는 저장하는 기법을 제시하고자 한다.

• 한국CDE학회논문집
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• 제1권1호
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• pp.1-19
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• 1996

Non-manifold topological representations can provide a single unified representation for mixed dimensional models or cellular models and thus have a great potential to be applied in many application areas. Various boundary representations for non-manifold topology have been proposed in recent years. These representations are mainly interested in describing the sufficient adjacency relationships and too redundant as a result. A model stored in these representations occupies too much storage space and is hard to be manipulated. In this paper, we proposed a compact hierarchical non-manifold boundary representation that is extended from the half-edge data structure for solid models by introducing the partial topological entities to represent some non-manifold conditions around a vertex, edge or face. This representation allows to reduce the redundancy of the existing schemes while full topological adjacencies are still derived without the loss of efficiency. To verify the statement above, the storage size requirement of the representation is compared with other existing representations and present some main procedures for querying and traversing the representation. We have also implemented a set of the generalized Euler operators that satisfy the Euler-Poincare formula for non-manifold geometric models.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권4호
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• pp.923-948
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• 2013

The main concern in mobile peer-to-peer (P2P) networks is security because jamming or eavesdropping on a wireless link is much easier than on a wired one and such damage can be incurred without physical access or contact. In particular, authentication has increasingly become a requirement in mobile P2P environments. This paper presents a new mutual authentication mechanism which requires less storage space and maintains a high level of security in mobile P2P networks. The proposed mechanism improves efficiency by avoiding the use of centralized entities and is designed to be agile in terms of both reliability and low-cost implementation. The mechanism suggested in the simulation evaluates the function costs occurring in authentication between the devices under mobile P2P network environment comparing to existing method in terms of basic operation costs, traffic costs, communications costs, storage costs and scalability. The simulation results show that the proposed mechanism provides high authentication with low cryptography processing overhead.

• 대한의용생체공학회:의공학회지
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• 제14권1호
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• pp.9-16
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• 1993

For efficient storage and transmission of medical images, the requirement of image com pression is increasing. Because differences between reconstructed images and original images are related with errors In the diagnosis, lossless compression is generally preferred in mod- ical images. in Run Length Coding which is one of the lossless compression method, we have applied modified scanning direction based on the Hilbert curve, which is a kind of space fill ins curve. We have substituted the traditional raster scanning by Hilbert curve direction scanning. Using this method, we have studied enhancement of compression efficiency for medical images.

• 전자공학회논문지B
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• 제31B권4호
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• pp.106-114
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• 1994

A new merging technique is adopted for combining rectangular parallelepipes produced by 2-D rectangular code into more intuitive 30D volume elements. Rectangular parallelepiped codes (RP codes) can be used in volume-based representation of a three-dimensional object. We proposed more regularity-conserving 2-D rectangular coding scheme to merge rectangular cells represented by RP codes in three-dimensional space. After being constructed from modified 2-D rectangular code, 3-D RP codes are merged in the two orthogonal directions using new merging algorithm. The shape of merged 3-D object reconstructed by proposed algorithm is shown to be much closer to the original object shape than that of conventional RP codes. The storage requirement of merged object can be also reduced.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
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• pp.886-893
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• 2002

The standard Hough transform has been dominantly used to detect straight lines in an image. However, massive storage requirement and low precision in estimating line parameters due to the quantization of parameter space are the major drawbacks of the Hough transform technique. In this paper, to overcome the drawbacks, an iterative algorithm based on a self-organizing map is presented. The self-organizing map can be adaptively learned such that image points are clustered by prominent lines. Through the procedure of the algorithm, a set of lines are sequentially detected one at a time. Computational results for synthetically generated images are given. The promise of the algorithm is also demonstrated with its application to two natural images of inserts.

• Journal of Communications and Networks
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• 제9권2호
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• pp.141-149
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• 2007

Multiple-input multiple-output (MIMO) transmit pre-coding/beamforming can significantly improve system spectral efficiency. However, several obstacles prevent precoding from wide deployment in early wireless networks: The significant feedback overhead, performance degradation due to feedback delay, and the large storage requirement at the mobile devices. In this paper, we propose a precoding method that addresses these issues. In this approach, only 3 or 6 bits feedback is needed to select a precoding matrix from a codebook. There are fifteen codebooks, each corresponding to a unique combination of antenna configuration (up to 4 antennas) and codebook size. Small codebooks are prestored and large codebooks are efficiently computed from the prestored codebook, modified Hochwald method and Householder reflection. Finally, the feedback delay is compensated by channel prediction. The scheme is validated by simulations and we have observed significant gains comparing to space-time coding and antenna selection. This solution was adopted as a part of the IEEE 802.16e specification in 2005.

• 한국소프트웨어감정평가학회 논문지
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• 제15권2호
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• pp.129-140
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• 2019

In the IoT environment, there is a huge amount of heterogeneous devices with limited capacity. Existing trust evaluation methods are not adequate to accommodate this requirement due to the limited storage space and computational resources. In addition, since IoT devices are mainly human operated devices, the trust evaluation should reflect the social relations among device owners. There is also a need for a mechanism that reflects the tendency of the trustor and environmental factors. In this paper, we propose an adaptable trust evaluation method for SOA-based IoT system to deal with these issues. The proposed model is designed to minimize the confidence bias and to dynamically respond to environmental changes by combining direct evaluation and indirect evaluation. It is expected that it will be possible to secure trust through quantitative evaluation by providing feedback based on social relationships.

• 한국생활과학회지
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• 제20권3호
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• pp.691-711
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• 2011

This study examines the preliminary license and approval facilitation standards for improvements in quality for childcare centers focusing on the number of children, building space standards, facilities and equipment, and childcare program. Data from 48 caese was collected from childcare centers nationwide in Korea through a questionnaire and building plan. The first step for starting care licensing is to work out the ages and numbers of children within four or five age ranges. The second step is to work out the number of children as small, medium, or large considering staff to child ratios and building size. The Nnext step is to make a choice about childcare service quality classification as minimum, fair, or good, considering space requirements per child for the building, the classroom and the outdoor playground. The next step is to make a choice of space organization relating to service programs, considering the sleeping and eating area, indoor play area, toilet & washing facilities, classroom layouts such as cluster type, double zone type, single zone type, and others. Also, each room and entrance, office, kitchen, storage, laundry, teacher's area, and chilldren's area, need to be checked for space requirements and performances. The last step is to arrange the childcare program with the building and site plan. In conclusion childcare service quality will get better by upgrading of license regulation especially in minimum space requirements per child, corresponding with an increase in GNP and housing area per person. This is needed for childcare licensing in order to determine the quality level of childcare service.