• 한국CDE학회논문집
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• 제8권2호
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• pp.75-83
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• 2003

In this paper, OSP(Octal Space Partitioning) tree is proposed for the real time culling of infinite sets of geometries in interactive Virtual Environment applications. And MSVBSP(Modified Shadow Volume BSP) tree is suggested for the occlusion culling. Experimental results show that the OSP and MSVBSP tree are efficiently implemented in real time rendering of interactive geometries.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2017년도 춘계학술발표대회
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• pp.787-790
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• 2017

Data quality is the main issue in the classification problems; generally, the presence of noisy instances in the training dataset will not lead to robust classification performance. Such instances may cause the generated decision tree to suffer from over-fitting and its accuracy may decrease. Decision trees are useful, efficient, and commonly used for solving various real world classification problems in data mining. In this paper, we introduce a preprocessing technique to improve the classification accuracy rates of the C4.5 decision tree algorithm. In the proposed preprocessing method, we applied the naive Bayes classifier to remove the noisy instances from the training dataset. We applied our proposed method to a real e-commerce sales dataset to test the performance of the proposed algorithm against the existing C4.5 decision tree classifier. As the experimental results, the proposed method improved the classification accuracy by 8.5% and 14.32% using training dataset and 10-fold crossvalidation, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.334-335
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• 2006

Solid insulation exposed to voltage is degraded by electrical tree process. And the degradation of the insulation is accelerated by voltage application. For this experimental, specimen of electrical tree model is made by XLPE (cross-linked polyethylene). And the size of the specimen is 7*5*7 $mm^3$. Distance of needle and plane is 2 mm. Voltages applied for acceleration test are 12 kV to 15 kV. And distribution characteristic of degraded stage is studied too. As a PD detecting and data process, discharge data acquire from PD detecting system (Biddle instrument). The system presents statistical distribution as phase resolved. Moreover the processing time of electrical tree is recorded to know the speed of degradation according to voltage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.172-175
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• 1992

This paper proposes the methods to construct the tree-structured database and analyze the distribution system network. In order to cope with an extensive amount of data and the frequent breaker switching operations in distribution systems, the database for system configuration is constructed using binary trees. Once the tree-structured database has been built, the system tracing of distribution network can be rapidly performed. This remarkably enhances the efficiency of data search and easily adapts to system changes due to switching operations. The computation method of fast power flow using tree search strategies is presented. The methods in the paper may be available in the field of distribution system operation.

• Spatial Information Research
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• 제15권2호
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• pp.181-187
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• 2007

수치고도자료를 생성하기 위해서, 항공기 혹은 위성에 탑재된 센서로부터 획득한 입체영상으로부터 자동상관매칭기법에 의해 고도값을 획득하는 연구가 수행되어 왔다. 자동상관매칭에 의한 결과값은 센서의 각도 및 수목 등에 의해 지표고도를 직접 추출하는데는 한계가 있고 영상내 지형지물 분포에 의해 고도값의 수정, 편집량이 결정된다. 본 연구는 수목차폐율과 수목고 자료가 자동상관매칭 고도 결과값에 미치는 영향을 분석하였다.

• 인터넷정보학회논문지
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• 제7권4호
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• pp.91-99
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• 2006

점진적 파싱 기법은 프로그램의 점진적 구성을 허용하는 언어기반 환경의 중요한 부분이며, 프로그램의 변경된 부분에 대해서만 구문분석을 다시 함으로써 시스템의 성능을 향상 시킨다. 기존의 점진적 파싱은 파싱 정보를 저장하기 위해 스택 자료구조를 사용한다. 본 논문에서는 스택 자료구조를 사용하지 않고 노드 주소로 스레드를 추가하여 스레드 트리 구성 알고리즘을 제안한다. 또한 구성된 스레드 트리를 사용하여 5단계의 점진적 파싱 과정으로 나누어 점진적 스레드 트리 구성 알고리즘을 제안한다.

• Communications for Statistical Applications and Methods
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• 제24권6호
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• pp.543-559
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• 2017

Tree-based regression and classification ensembles form a standard part of the data-science toolkit. Many commonly used methods take an algorithmic view, proposing greedy methods for constructing decision trees; examples include the classification and regression trees algorithm, boosted decision trees, and random forests. Recent history has seen a surge of interest in Bayesian techniques for constructing decision tree ensembles, with these methods frequently outperforming their algorithmic counterparts. The goal of this article is to survey the landscape surrounding Bayesian decision tree methods, and to discuss recent modeling and computational developments. We provide connections between Bayesian tree-based methods and existing machine learning techniques, and outline several recent theoretical developments establishing frequentist consistency and rates of convergence for the posterior distribution. The methodology we present is applicable for a wide variety of statistical tasks including regression, classification, modeling of count data, and many others. We illustrate the methodology on both simulated and real datasets.

• Spatial Information Research
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• 제19권2호
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• pp.71-76
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• 2011

본 논문에서는 특정 지역의 전력 소비 데이터를 이용하여 safe와 non-safe 전력 부하 라인의 차이를 분석하여 정의하고, 출현패턴을 사용하여 잠재되어 있는 non-safe라인을 식별하기 위하여 제한된 메모리에서 효율적으로 패턴을 찾을 수 있는 TFP-tree 기반의 점진적 출현패턴 마이닝 알고리즘을 제안한다. 특히, 두 개의 다른 최소 지지도 값을 사용하여 전력 소비 데이터와 같은 대용량 데이터에서의 마이닝 문제를 해결한다.

• 품질경영학회지
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• 제48권2호
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• pp.297-307
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• 2020

Purpose: The purpose of this study is to analyze the factors that affect ammunition performance by applying data mining techniques to the Ammunition Stockpile Reliability Program (ASRP) data of the 155mm propelling charge. Methods: The ASRP data from 1999 to 2017 have been utilized. Logistic regression and decision tree analysis were used to investigate the factors that affect performance of ammunition. The performance evaluation of each model was conducted through comparison with an artificial neural networks(ANN) model. Results: The results of this study are as follows; logistic regression and the decision tree analysis showed that major defect rate of visual inspection is the most significant factor. Also, muzzle velocity by base charge and muzzle velocity by increment charge are also among the significant factors affecting the performance of 155mm propelling charge. To validate the logistic regression and decision tree models, their classification accuracies have been compared with the results of an ANN model. The results indicate that the logistic regression and decision tree models show sufficient performance which conforms the validity of the models. Conclusion: The main contribution of this paper is that, to our best knowledge, it is the first attempt at identifying the significant factors of ASPR data by using data mining techniques. The approaches suggested in the paper could also be extended to other types ammunition data.

• Journal of Information Technology Applications and Management
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• 제13권4호
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• pp.257-271
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• 2006

Recently, flash memories are one of best media to support portable computer's storages in mobile computing environment. The features of non-volatility, low power consumption, and fast access time for read operations are sufficient grounds to support flash memory as major database storage components of portable computers. However, we need to improve traditional Indexing scheme such as B-Tree due to the relatively slow characteristics of flash operation as compared to RAM memory. In order to achieve this goal, we devise a new indexing scheme called F-Tree. F-Tree improves tree operation performance by compressing pointers and keys in tree nodes and rewriting the nodes without a slow erase operation in node insert/delete processes. Based on the results of the performance evaluation, we conclude that F-Tree indexing scheme outperforms the traditional indexing scheme.