• Journal of Industrial Convergence
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• v.21 no.7
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• pp.29-39
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• 2023

In the recent period, there have been numerous earthquakes both domestically and internationally, and buildings in South Korea are particularly vulnerable to seismic design and earthquake damage. Therefore, the objective of this study is to discover an effective method for assessing the seismic vulnerability of buildings and conducting a density analysis of high-risk structures. The aim is to model this approach and validate it using data from pilot area(Seoul). To achieve this, two modeling techniques were employed, of which the predictive accuracy of the statistical analysis technique was 87%. Among the machine learning techniques, Random Forest Model exhibited the highest predictive accuracy, and the accuracy of the model on the Test Set was determined to be 97.1%. As a result of the analysis, the district rating revealed that Gwangjin-gu and Songpa-gu were relatively at higher risk, and the density analysis of at-risk buildings predicted that Seocho-gu, Gwanak-gu, and Gangseo-gu were relatively at higher risk. Finally, the result of the statistical analysis technique was predicted as more dangerous than those of the machine learning technique. However, considering that about 18.9% of the buildings in Seoul are designed to withstand the Seismic intensity of 6.5 (MMI), which is the standard for seismic-resistant design in South Korea, the result of the machine learning technique was predicted to be more accurate. The current research is limited in that it only considers buildings without taking into account factors such as population density, police stations, and fire stations. Considering these limitations in future studies would lead to more comprehensive and valuable research.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.524-527
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• 2002

본 연구에서는 Support Vector Machine(SVM)을 이용한 호스트 기반 침임 탐지 방법을 제안한다. 침입 탐지는 침입과 정상을 판단하는 이진분류 문제이므로 이진분류에 뛰어난 성능을 발휘하는 SVM을 이용하여 침입 탐지 시스템을 구현하였다. 먼저 감사자료를 system call level에서 분석한 후, sliding window기법에 의해 패턴 feature를 추출하고 training set을 구성하였다. 여기에 SVM을 적용하여 decision model을 생성하였고, 이에 대한 판정 테스트 결과 90% 이상의 높은 침입탐지 적중률을 보였다.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.337-340
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• 2000

비디오객체 추출 기법은 MPEG-4 및 MPEG-7의 응용을 목표로 최근 활발하게 연구되고 있다. 이들 연구는 객체 추출의 전체적인 구조와 정확한 윤곽선 검출 알고리즘의 개발에 초점을 맞추고 있으며 제한적인 조건하에서 만족할 만한 성능을 내고 있다 그러나, 카메라 움직임, 객체의 빠른 움직임, 비강체 운동 등 보다 일반적인 상황에서는 객체 추출의 안정성이 떨어진다. 본 논문에서는 객체 추출의 안정성을 높이기 위해 칼라, 움직임 정보 등의 특징정보(feature)가 균일한 영역으로 사전분할하고, 분할된 균일영역을 추적하는 알고리즘을 제안한다. 추적된 균일 영역간의 경계는 각 영역의 통계적 분포와 영역경계의 윤곽선으로 정의된 에너지를 레벨셑 방법으로 최소화함으로 조정된다.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.10
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• pp.465-472
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• 2017

In the past, researchers mainly used the supervised learning technique of machine learning to analyze power data and investigated the identification of patterns through the data mining technique. Data analysis research, however, faces its limitations with the old data classification and analysis techniques today when the size of electric power data has increased with the possible real-time provision of data. This study thus set out to propose a clustering architecture to analyze large-sized electric power data. The clustering process proposed in the study supplements the K-means algorithm, an unsupervised learning technique, for its problems and is capable of automating the entire process from the collection of electric power data to their analysis. In the present study, power data were categorized and analyzed in total three levels, which include the row data level, clustering level, and user interface level. In addition, the investigator identified K, the ideal number of clusters, based on principal component analysis and normal distribution and proposed an altered K-means algorithm to reduce data that would be categorized as ideal points in order to increase the efficiency of clustering.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.10
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• pp.1-8
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• 2000

In this paper, positioning schemes based on AOA(Angle of Arrival), TOA(Time of Arrival), and TDOA(Time Difference of Arrival) measurements are reviewed and analyzed. In the case of using those schemes in microcell structure with severe multipath fading and shadowing conditions, the rapid and unpredictable variation of signal level makes it difficult to estimate the position and velocity of mobiles. Therefore, we propose a novel mobile tracking method based on the multicriteria decision making, in which uncertain parameters such as RSS(Received Signal Strength), the distance between mobile and base station, the moving direction, and the previous location are participated in the decision process using aggregation function in fuzzy set theory. Through a simulation, we analysis the impaction of the frequent change of direction and speed of mobiles.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1223-1228
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• 2011

A moving-coil type linear actuator has been widely used in the system reciprocating short stroke because of its several advantages, such as the structural simplicity, low weight and a fast control response speed. This paper presents a design approach for improving the actuating performance with a clear expression of optimal configuration represented by a level set function. The optimization problem is formulated to minimize the variation of magnetic force at every moving displacement of the mover for fast and easy control. To consider the manufacturability of actuator, the concept of phase-field model is incorporated to control the complexity of structural boundaries. To verify the usefulness of the proposed method, the core design example of cylindrical linear actuator is performed.

• The KIPS Transactions:PartB
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• v.18B no.3
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• pp.131-138
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• 2011

In this paper, we compare our proposed method with previous methods for the volumetric image segmentation using level set. In order to obtain an exact segmentation, the region and boundary information of image object are used in our proposed speed function. The boundary information is defined by the gradient vector flow obtained from the gradient images and the region information is defined by Gaussian distribution information of pixel intensity in a region-of-interest for image segmentation. Also the regular term is used to remove the noise around surface. We show various experimental results of real medical volume images to verify the superiority of proposed method.

• Journal of the Korea Society for Simulation
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• v.11 no.1
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• pp.59-70
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• 2002

This article presents the results of research to develop a descriptive model of firm-level productivity that will allow a myriad of factor interactions to be directly accounted for. The model is a linked set of equations that attempt to capture how changes in one-factor influences the level of another factor. and ultimately bottom-line performance. The model is coded in SIMAN. It is used to determine the best use of an infusion of funds should they go for additional automation, or training etc. An application of the model to U.S. industry is presented based on parameter values obtained through a national survey.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.664-671
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• 2017

This paper presents a numerical analysis of behaviors of rear closer of vertical launch system under rocket plume based on fluid structure interaction analysis. The rocket plume loading is modeled by fully Eulerian method and elasto-plastic behavior of rear cover is calculated by total Lagrangian method based on a 9-node planar element. The interface motion and boundary conditions are described by a hybrid particle level-set method within the ghost fluid framework. We compare the fluid flow pattern between different rear closer models which are elast-plastic and rigid deformation.

• Journal of computational fluids engineering
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• v.22 no.1
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• pp.81-87
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• 2017

The characteristics of flow past a square cylinder submerged under the free surface have been numerically studied. An immersed boundary method was adopted for implementation of the cylinder cross-section in a Cartesian grid system. Also, a level-set method was used to capture the interface of the two fluids. The case for Reynolds number 150 was examined. At the specific Reynolds number, by varying the gap ratio(0.25, 0.40, 0.55, 0.70, 1.00, 1.50, 2.50, 5.00) the effects of the free surface on the force coefficients and Strouhal number of vortex shedding were identified. The presence of the free surface very close to the cylinder significantly affects the shedding pattern, resulting in considerable deviation of the force coefficients and Strouhal number from those of the single-phase flow. In addition, the influence of Froude number was considered in this study. By increasing Froude number(0.2-0.4), flow topology change was identified at the specific gap ratios(0.40, 0.70, 1.50, 5.00).