• 한국안전학회지
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• 제15권1호
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• pp.100-105
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• 2000

Correlation between propagation of bush-type electrical tree and internal partial discharges(PD) was discussed. We used specimens with needle-plane electrode system made of LDPE(Low Density Polyethylene), observed inception and propagation of electrical tree by optical microscope interfaced with computer and investigated characteristics of phase resolved PD pulses accompanying with propagation of electrical tree. Electrical tree generally growed bush-type tree. PD data detected and analyzed were average discharge current and statistical operator of q-n, $\psi$- $q_{avg}$, $\psi$-n, ${\psi}-q_{max}$ distribution. Parameters used were skewness, kurtosis, average discharge phase, cross-correlation factor, asymmetry and etc. In generally, average discharge current had good linear relationship with propagation of bush type electrical tree on this experiment. Peak discharge magnitude and repetition rate were increased, but they had not good linear relationship.p.

• 한국멀티미디어학회논문지
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• 제10권3호
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• pp.358-364
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• 2007

본 논문에서는 집성 트리를 이용한 MPLS 복구 방안을 제시한다. MPLS에서 장애 복구를 위한 효과적인 방안으로, 다수의 노드에서 하나의 목적지 노드로 향하는 집성 트리를 통해 장애가 생긴 경로를 목적지 노드별로 그룹 복원하는 방안을 제시한다. 집성 트리는 하나의 노드에서 보낸 메시지가 복수의 노드에게로 전달되는 멀티캐스트 트리와 반대로, 복수의 노드에서 하나의 목적지 노드를 향해 정보가 전달되는 데이터 전달 트리이다. 실험을 통해 집성 트리를 이용한 그룹 복구 방안은 기존의 단일 복구 방안과 비교하여, 보다 빠른 속도로 복구함을 확인할 수 있었다.

• 정보처리학회논문지D
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• 제12D권7호
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• pp.965-978
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• 2005

소프트웨어 개발 시, 일정과 품질에 저해 요인이 되는 결함이 다수 존재한다. 일정과 품질의 저해 요인을 제거하고 동시에 체계적으로 이를 관리하기 위하여 본 논문에서는 opportunity tree 프레임워크를 설계한다. 유사한 프로젝트를 수행 시 영역 전문가의 지식을 활용한 opportunity tree 발생되는 문제점을 예측, 대비할 수 있게 하여, 소프트웨어 프로세스를 개선할 수 있다 본 연구에서는 소프트웨어 개발 시 발생하는 일정관리에 대한 결함을 찾아내고, 원인을 식별 및 해결책을 제시하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제2권2호
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• pp.82-102
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• 2008

Packet losses tend to occur during short error bursts separated by long periods of relatively error-free transmission. There is also a significant spatial correlation in loss among the receiver nodes in a multicast session. To recover packet transmission errors at the transport layer, tree-based protocols construct a logical tree for error recovery before data transmission is started. The current tree construction scheme does not scale well because it overloads the sender node. We propose a scalable recovery tree construction scheme considering these properties. Unlike the existing tree construction schemes, our scheme distributes some tasks normally handled by the sender node to specific nodes acting as repair node distributors. It also allows receiver nodes to adaptively re-select their repair node when they experience unacceptable error recovery delay. Simulation results show that our scheme constructs the logical tree with reduced message and time overhead. Our analysis also indicates that it provides fast error recovery, since it can reduce the number of additional retransmissions from its upstream repair nodes or sender node.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2060-2062
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• 1999

When the high voltage is applied on insulation materials that have voids and impurities inner one, then probability of electrical tree inception is increased at defects. Electrical tree gives a profit to degradation analysis, because it is possible to observe by eyes and provides electrical degradation step. And electrical tree is divided to three types in usual - tree type, bush type and chestnut type tree. But these three types are divided not by method of quantitative analysis but visual and experiential analysis. In this paper, three types of electrical tree were calculated by quantitative analysis using fractal mathematics and classified to fractal dimensions (FD). FD of tree types are 1.1$\sim$1.4, bush types are 1.4$\sim$1.6 and chestnut type trees have above 1.6 FD.

• 한국컴퓨터정보학회논문지
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• 제12권4호
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• pp.111-117
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• 2007

본 논문에서는 정규 허프만 트리의 성질을 이용하여 허프만 코드를 효율적으로 디코딩 하는 방법을 제안하고 그 특성을 살펴보았다. 허프만 코드를 정규 허프만 트리로 변환한 후 각 레벨의 단말 노드 값들에 대한 규칙을 이용하여 최소한의 정보로 허프만 트리를 표현하였다. 제안한 방법은 기존의 방법과 동일한 수행 시간을 유지하며 트리정보를 위한 메모리를 줄일 수 있었다. 트리정보를 저장하기 위한 메모리의 크기는 2h + 2klogn로서 기존의 방법들보다 적었으며 심벌로 변환하기 위한 검색의 수는 비슷하였다.

• 한국가구학회지
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• 제23권4호
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• pp.479-484
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• 2012

Tree-ring dating can be used to date scientifically prehistoric timbers, historical buildings or woodcrafts. It gives a calendar year to each tree ring and produces the felling dates of logs or wood panels. In this study, we applied tree-ring dating to a medicine cabinet in Seoul Museum of History. We obtained tree-ring data from radial or cross section by taking photographs with a digital camera. The cabinet were dated A.D. 1821 to the last ring. It was about 50 year older than the previous medicine cabinets. Tree-ring patterns indicated that the origin of woods for the cabinet would be near Sorak mountains.

• International Journal of Computer Science & Network Security
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• 제21권7호
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• pp.56-62
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• 2021

The surge in generic attacks execution against cipher text on the computer network has led to the continuous advancement of the mechanisms to protect information integrity and confidentiality. The implementation of explicit decision tree machine learning algorithm is reported to accurately classifier generic attacks better than some multi-classification algorithms as the multi-classification method suffers from detection oversight. However, there is a need to improve the accuracy and reduce the false alarm rate. Therefore, this study aims to improve generic attack classification by implementing two hybridized decision tree algorithms namely Naïve Bayes Decision tree (NBTree) and Logistic Model tree (LMT). The proposed hybridized methods were developed using the 10-fold cross-validation technique to avoid overfitting. The generic attack detector produced a 99.8% accuracy, an FPR score of 0.002 and an MCC score of 0.995. The performances of the proposed methods were better than the existing decision tree method. Similarly, the proposed method outperformed multi-classification methods for detecting generic attacks. Hence, it is recommended to implement hybridized decision tree method for detecting generic attacks on a computer network.

• Journal of Forest and Environmental Science
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• 제35권2호
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• pp.115-120
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• 2019

There are many countries having a long history of exotic tree introduction from different countries and several countries including New Zealand, Brazil and Hungary have successfully introduced exotic trees. Korea's tree breeding program for introduction of exotic tree was originally started from 1924. Records reveal that hundreds of tree species were introduced from many countries and tested their germination and viability. About 415 introductions were eliminated since they had been introduced and tested. Subsequently, seven exotic trees that proved successful in trials and plantations have planted for afforestation. Simultaneously, several promising exotic trees are still under the test. In this paper, we will succinctly review and evaluate their comparative growth performance of the exotic trees in the plantation programs of the country to coping with climate change.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2021년도 제63차 동계학술대회논문집 29권1호
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• pp.287-288
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• 2021

본 논문에서는 macOS의 파일시스템인 HFS+의 B-tree구조를 디지털 포렌식의 관점에서 분석할 수 있는 기능을 갖춘 도구의 구현에 대하여 다룬다. HFS+ 파일시스템의 파일과 디렉토리에 대한 메타정보를 카탈로그 B-tree에서 구하여 디지털 포렌식 정보로 활용한다. HFS+파일시스템 포렌식 분석도구는 C/C++언어로 구현된다. 텍스트 기반의 명령행 프로그램으로 구현되며 macOS/Windows에서 터미널/명령프롬프트에서 각각 실행될 수 있도록 제작된다. 타임스탬프/파일크기/위치 등의 메타데이터의 파싱기능, 리프노드에 저장된 데이터를 이용한 파일/디렉토리 트리 구조의 재구성, B-tree구조에 의한 키워드 탐색 기능, 인덱스 노드 없이 B-tree 리프노드의 구성에 의한 파일/디렉토리 파싱/검색 기능 등이 구현된다.