• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.928-931
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• 2002

Network based intrusion detection system is a computer network security tool. In this paper, we present an intrusion detection system based on Self-Organizing Maps (SOM) and Resilient Propagation Neural Network (RPROP) for visualizing and classifying intrusion and normal patterns. We introduce a cluster matching equation for finding principal associated components in component planes. We apply data from The Third International Knowledge Discovery and Data Mining Tools Competition (KDD cup'99) for training and testing our prototype. From our experimental results with different network data, our scheme archives more than 90 percent detection rate, and less than 5 percent false alarm rate in one SYN flooding and two port scanning attack types.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.107-110
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• 2000

화학 박막 증착용(CVD : Chemical Vapor Deposition) 클러스터 장비는 다양한 공정 경로가 가능하며 물류 흐름이 매우 복잡해질 수 있다. 또한, 공정이 종료된 웨이퍼는 제한 시간 내에 챔버에서 꺼내져야만 한다. 클러스터 장비는 두 개의 팔을 가진 로봇이며, 빈 쪽 팔을 이용하여 공정이 종료된 웨이퍼를 꺼낸 후, 다른 쪽 팔을 이용하여 이전 공정에서 가져온 웨이퍼를 해당 공정에 넣어 주는 스왑(SWAP) 방식으로 운영된다. 이러한 스왑 방식에서는 로봇 작업 순서가 결정되어 진다. 그러나, 로봇의 팔 이외에 임시버퍼가 없고, 각 챔버는 엄격한 체제 시간 제약(Residency Time Constraint)을 가지고 있기 때문에 로봇의 작업 시점의 제어가 필요하다. 본 논문에서는 간단한 Earliest Starting 방식으로 로봇의 작업 시점을 제어한다고 가정했을 때, 스왑 방식을 운용하면서 체제 시간 제약을 만족하는 공정 시간들의 조건을 제시한다. 공정 시간은 엔지니어에 의해 다소 조정이 가능하므로 공정 시간들의 조건은 엔지니어에게 스케줄 가능한 공정 시간을 결정할 수 있도록 지원해 주는 시스템에 활용 가능하다. 또한, 본 논문에서는 FSM(Finite State Machine)을 이용하여 CTC(Cluster Tool Controller) 내부의 실시간 스케줄러 구현 방법을 제안한다.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.4
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• pp.404-409
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• 2011

Report on the notion of uncertainty is important. The reason is that the measured value includes a lot of uncertain factors. Reliable results can't be derived without the notion of uncertainty. The mathematical model to evaluate uncertainty considering the quality of vibration is important to evaluate uncertainty, and it must contain the every quantity which contributes significantly to uncertainty in the measured results. In this paper, the evaluation of uncertainty analysis about rotor vibration measurements of machine tools is presented to evaluate the most important factors of uncertainty.

• Nuclear Engineering and Technology
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• v.36 no.3
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• pp.229-236
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• 2004

Radiation hardening is a multiscale phenomenon involving various processes over a wide range of time and length. We present a multiscale model for estimating the amount of radiation hardening in pressure vessel steel in the environment of a light water reactor. The model comprises two main parts: molecular dynamics (MD) simulation and a point defect cluster (PDC) model. The MD simulation was used to investigate the primary damage caused by displacement cascades. The PDC model mathematically formulates interactions between point defects and their clusters, which explains the evolution of microstructures. We then used a dislocation barrier model to calculate the hardening due to the PDCs. The key input for this multiscale model is a neutron spectrum at the inner surface of reactor pressure vessel steel of the Younggwang Nuclear Power Plant No.5. A combined calculation from the MD simulation and the PDC model provides a convenient tool for estimating the amount of radiation hardening.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.42.1-42.1
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• 2014

A gravitational weak-lensing map provides a weighted "picture" of the projected surface mass density and is to be an important tool for identifying "mass-selected" clusters of galaxies. However, weak-lensing maps have a limitation due to the projection of large-sclae structure along the line-of-sight. Geller et al. (2010) and Kurtz et al. (2012) compared massive clusters identified in a dense redshift survey with significant weak-lensing map convergence peaks. Both assessments of the efficiency of weak-lensing map for cluster identification did not draw a general conclusion, because the sample is so small. Thus, we additionally perform deep imaging observations of fields in a dense galaxy redshift survey that contain galaxy clusters at z~0.2-0.5, using CFHT Megacam. Our study will provide an important opportunity to examine the efficiency and completeness of a weak-lensing selection, and further to improve the method of cluster identification in future weak-lensing surveys.

• Journal of the Korean Home Economics Association
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• v.41 no.6
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• pp.13-28
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• 2003

The purposes of this study were to identify money altitudes of college students and to examine both socio-economic characteristics and clothing purchase behaviors by different money attitudes. For this study, guestionnaires completed by 2-year and 4-year college students (n=426) were analyzed by factor analysis, cluster analysis, X²- test, and ANOVA. The results of this study were as follows: First, the money attitudes were composed of five factors and they were categorized by three clusters: cluster of considering the money as a tool for future safety, a way of approval and filling up emotions, and inclination toward stinginess and distrust. Second, the factors which were associated with money attitudes were academic level, education level of parents, household income, students' own income, and the economic level of their households. Third, in each type of attitudes, the clothing purchase behavior had four steps of decision making: problem recognition, information search, evaluation of alternatives, and the purchase. There were significant differences in the clothing purchase behavior among the money attitude styles.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.9-16
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• 2016

In this paper, we present a performance evaluation agent based on fuzzy cluster analysis and validity measures. The proposed agent is consists of three modules, fuzzy cluster analyzer, performance evaluation measures, and feature ranking algorithm for feature selection step in CAD system. Feature selection is an important step commonly used to create more accurate system to help human experts. Through this agent, we get the feature ranking on the dataset of mass and calcification lesions extracted from the public real world mammogram database DDSM. Also we design a CAD system incorporating the agent and apply five different feature combinations to the system. Experimental results proposed approach has higher classification accuracy and shows the feasibility as a diagnosis supporting tool.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.253-255
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• 2002

최근 인터넷 서버의 역할을 위해 24 시간 무정지 서비스가 요구되면서 여러 개의 단일 서버를 고속의 네트웍으로 연결한 클러스터 DMBS 에 관한 연구가 국내외적으로 활발히 진행중이다. 그러나, 이러한 클러스터 DBMS를 효율적으로 관리할 수 있는 관리 도구에 대한 연구는 미흡한 실정이다. 본 논문에서는 각 서버의 상태를 모니터링한 정보를 바탕으로 서버의 오류를 감지하고 복구함으로써, 전체 클러스터 DBMS가 정상적인 서비스를 할 수 있도록 지원할 수 있는 고가용성 클러스터 관리기률 설계하고 구현한다.

• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.25-30
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• 2018

Pattern classification system is often an important component of intelligent systems. In this paper, we present a pattern classification system consisted of the feature selection module, knowledge base construction module and decision module. We introduce a feature impact evaluation selection method based on fuzzy cluster analysis considering computational approach and generalization capability of given data characteristics. A fuzzy neural network, OFUN-NET based on unsupervised learning data mining technique produces knowledge base for representative clusters. 240 blemish pattern images are prepared and applied to the proposed system. Experimental results show the feasibility of the proposed classification system as an automating defect inspection tool.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.8
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• pp.43-49
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• 2020

The growth of the AR/VR market due to the advent of the 4th Industrial Revolution begins with the development of the display industry. The development of OLED and flexible displays is further accelerated by the development of R2R technology. Micro-processing technology using a fast tool servo (FTS), the core technology in R2R processes, is making technological progress in increasingly diverse ways. This paper proposes a method to develop an FTS for horizontal driving and presents this method through experiments and analyses. To develop a swing-type FTS based on a seesaw motion, a rotational moment hinge structure was designed for each type, and research was conducted to determine an effective design method. A cantilever-based swing-type FTS was developed in two variations: one with single-side hinges and another with dual-side hinges. The parameters in the design of the swing-type FTS are rotational moment, natural frequency, and material selection. In conclusion, an FTS with a single-side hinge demonstrates the high performance required for micro processing.