• 한국정보처리학회논문지
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• 제6권12호
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• pp.3469-3476
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• 1999

공간적인 자료구조를 기반으로 하는 공간 데이터베이스에서는 일차원 색인구조와는 달리 공간객체들의 다차원적인 특성에 부합되는 새로운 색인구조가 요구되고 있다. 본 논문에서는 이러한 요구사항을 충족시키기 위하여 기존 다차원 색인구조들의 특징 분석을 통하여 공간 데이터베이스의 효율적인 검색을 위한 새로운 색인구조를 제안하였다. 기존 X-트리에서 슈퍼노드의 순차적인 검색방법의 개선과 방대한 슈퍼노드가 생성되는 경우에도 검색시간의 단축이 가능하도록 하기 위하여, 포인트 색인구조를 갖는 kd-트리를 X-트리에 병합시킨 색인구조를 제안하였다. 제안된 색인구조를 실제로 구현하여 실험 데이터의 차원과 분포에 따라 검색시간을 분석하였다.

• 제어로봇시스템학회논문지
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• 제14권11호
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• pp.1110-1116
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• 2008

In this paper, we suggest GP operators based on tree structure considering tree distributions in structure space and structural difficulties. The main idea of the proposed genetic operators is to place generated offspring into the specific region which nodes and depths are balanced and most of solutions exist. To enable that, the proposed operators are designed to utilize region information where parents belong and node/depth rates of selected subtree. To demonstrate the effectiveness of our proposed approach, experiments of binomial-3 regression, multiplexer and even parity problem are executed. The experiments results show that the proposed operators based on tree structure is superior to the results of standard GP for all three test problems in both success rate and number of evaluations.

• 한국지능시스템학회:학술대회논문집
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• 한국지능시스템학회 2008년도 춘계학술대회 학술발표회 논문집
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• pp.294-298
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• 2008

이메본 논문은 GP 트리의 노드포화도를 제어함으로써 트리의 구조공간에서 효율적인 개체 분포를 유도하는 GP 진화연산자를 제안한다. 특정 영역으로의 트리 개체의 분포가 성능에 미치는 영향을 검증하고 진화과정에서 나타나는 군집내의 개체 다양성과의 관계를 분석한다. 제안된 진화연산자를 회귀다항식, 멀티플렉서, 짝수 패리티의 3가지 벤치마크 문제에 대해서 실험을 하였고, 표준 GP 연산자와 비교하였다.

• KCI Concrete Journal
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• 제11권3호
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• pp.165-174
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• 1999

The objective of the research stated herein is to observe the elastic and inelastic behaviors and ultimate capacity of 1:5 scale 3-story reinforced concrete frame. Pushover tests were performed to 1:5 scale 3-story reinforced concrete frames with and without infilled masonry. To simulate the earthquake effect, the lateral force distribution was maintained by an inverted triang1e by using the whiffle tree. From the test results, the relation ships between the total lateral load and the roof drift, the distribution of column shears, the relation between story shear and story drift, and the angular rotations at the critical portions of structures were obtained. The effects of infilled masonry were investigated with regards to the stiffness, strength, and ductility of structures. Final collapse modes of structures with and without infilled masonry were compared.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.529-536
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• 1999

The objective of the research stated herein is to observe th elastic and inelastic behaviors and ultimate capacity of 1 : 5 scale 3-story reinforced concrete frame. Pushover tests were performed to 1:5 scale 3-story reinforced concrete frames without and with infilled masonry. To simulate the earthquake effect, the lateral force distribution was maintained to be an inverted triangle by using the whiffle tree. From the results of tests, the relations between the total lateral load and the roof drift, the distribution of column shears, the relation between story shear and story drift, and the angular rotations at the critical portions of structures were obtained. The effects of infilled masonry are investigated with regards to the stiffness, strength, and ductility of structures. Final collapse modes of structures with and without infilled masonry are compared.

• 인간식물환경학회지
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• 제24권2호
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• pp.219-227
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• 2021

Background and objective: Urban street trees play an important role in carbon reduction in cities where greenspace is scarce. There are ongoing studies on carbon reduction by street trees. However, information on the carbon reduction capacity of street trees based on field surveys is still limited. This study aimed to quantify carbon uptake and storage by urban street trees and suggest a method to improve planting of trees in order to increase their carbon reduction capacity. Methods: The cities selected were Sejong, Chungju, and Jeonju among cities without research on carbon reduction, considering the regional distribution in Korea. In the cities, 155 sample sites were selected using systematic sampling to conduct a field survey on street environments and planting structures. The surveyed data included tree species, diameter at breast height (DBH), diameter at root collar (DRC), height, crown width, and vertical structures. The carbon uptake and storage per tree were calculated using the quantification models developed for the urban trees of each species. Results: The average carbon uptake and storage of street trees were approximately 7.2 ± 0.6 kg/tree/yr and 87.1 ± 10.2 kg/tree, respectively. The key factors determining carbon uptake and storage were tree size, vertical structure, the composition of tree species, and growth conditions. The annual total carbon uptake and storage were approximately 1,135.8 tons and 22,737.8 tons, respectively. The total carbon uptake was about the same amount as carbon emitted by 2,272 vehicles a year. Conclusion: This study has significance in providing the basic unit to quantify carbon uptake and storage of street trees based on field surveys. To improve the carbon reduction capacity of street trees, it is necessary to consider planning strategies such as securing and extending available grounds and spaces for high-density street trees with a multi-layered structure.

• Journal of Electrical Engineering and information Science
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• 제2권4호
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• pp.37-45
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• 1997

With rapid increase of information requirements from various application areas, there has been much research on dynamic information storage structures that effectively support insertions, deletions and updates. In this appear we evaluate the performance of he existing dynamic signature file methods such as the S-tree, Quick Filter and HS file and provide guidelines for the most effective usage to a given operational environment. We derive analytic performance evaluation models of the storage structures based on retrieval time, storage overhead and insertion time. We also perform extensive experiments with various data distributions such as uniform, normal and exponential distributions. The relationships among various performance parameters are throughly investigated. We show through performance comparison based on analytic models and experiments that regardless of data distribution, the HS file significantly improves performance in both the retreival time and the storage overhead over S-tree and Quick Filter.

• 한국멀티미디어학회논문지
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• 제13권10호
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• pp.1534-1546
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• 2010

센서 네트워크에서는 에너지 소비를 줄이기 위해 다양한 계층적 클러스터링 방법이 제안되었다. 그러나 대부분의 연구에서 나타나는 문제점은 노드의 실제 배치를 생각하지 않고 일방적인 그리드 형태의 구조 또는 무작위 적인 클러스터 구조를 구성하는 것이다. 이렇게 구성된 클러스터는 클러스터의 크기와 포함된 노드의 수가 불균형하기 때문에 큰 에너지 효율을 보이기 힘들다. 그래서 본 논문에서는 실제 노드들이 배치가 된 후 R-Tree의 노드 분할 및 병합 알고리즘에 착안하여 보다 더 효율적인 클러스터를 구성할 수 있는 방법인 CSM(Clustering using Split & Merge algorithm)을 제안한다. 다양한 실험결과 CSM은 기존 방법보다 에너지 효율적인 클러스터링을 생성함으로써 최대 1.6배의 에너지 효율을 보였다.

• Structural Engineering and Mechanics
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• 제9권6호
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• pp.557-568
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• 2000

As time-variant reliability approaches become increasingly used for service life prediction of the aging infrastructure, the demand for computer solution methods continues to increase. Effcient computer techniques have become well established for the reliability analysis of structural systems. Thus far, however, this is largely limited to time-invariant reliability problems. Therefore, the requirements for time-variant reliability prediction of deteriorating structural systems under time-variant loads have remained incomplete. This study presents a computer program for $\underline{REL}$iability of $\underline{T}$ime-Variant $\underline{SYS}$tems, RELTSYS. This program uses a combined technique of adaptive importance sampling, numerical integration, and fault tree analysis to compute time-variant reliabilities of individual components and systems. Time-invariant quantities are generated using Monte Carlo simulation, whereas time-variant quantities are evaluated using numerical integration. Load distribution and post-failure redistribution are considered using fault tree analysis. The strengths and limitations of RELTSYS are presented via a numerical example.

• 한국컴퓨터정보학회논문지
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• 제27권12호
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• pp.209-217
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• 2022

함정 전투관리체계는 다양한 센서, 무장 장비들이 연동 노드를 통해 연결되며 체계내 노드간 효율적인 통신을 위해 DDS(Data Distribution Service) 통신을 활용한다. DDS를 사용하기 위해 체계내 응용소프트웨어 사이에는 DDS토픽을 기본으로 하는 PUB/SUB(Publication/Subscribe)방식으로 통신한다. 이 PUB/SUB방식으로 통신하는 DDS 메시지 구조가 일치하지 않으면 송수신 응용소프트웨어에서 잘못된 명령처리 및 정보전달 등 문제가 발생한다. 이를 개선하기 위해 본 논문에서는 해시트리를 활용한 DDS 메시지 구조 무결성 검증 방법을 제안한다. 제안하는 방법의 전투관리체계에 적용가능성을 확인하기 위해, 제안하는 방법의 메시지 구조 무결성 검증률을 측정하고 전투관리체계의 운용과 개발과정에 미치는 영향을 확인하기 위해 전투관리체계 초기화 시간 비교, 메시지 해시트리의 생성시간 측정을 하였다. 이 시험을 통해 본 논문에서 제안하는 체계 안정성을 위한 메시지 구조 검증 방법이 함정 전투관리체계에 적용 가능함을 확인하였다.