• Korean Journal of Optics and Photonics
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• v.15 no.1
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• pp.79-85
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• 2004

We report on a transmittance controlled photomask with phase patterns on the back quartz surface. Theoretical analysis for changes in illumination pupil shape with respect to the variation of size and density of backside phase patterns and experimental results for improvement of critical dimension uniformity on a wafer by using the transmittance controlled photomask are presented. As phase patterns for controlling transmittance of the photomask we used etched contact-hole type patterns with 180" rotative phase with respect to the unetched region. It is shown that pattern size on the backside of the photomask must be made as small as possible in order to keep the illumination pupil shape as close as possible to the original pupil shape and to achieve as large an illumination intensity drop as possible at a same pattern density. The distribution of illumination intensity drop suitable for correcting critical dimension error was realized by controlling pattern density of the contact-hole type phase patterns. We applied this transmittance controlled photomask to a critical layer of DRAM (Dynamic Random Access Memory) having a 140nm design rule and could achieve improvement of the critical dimension uniformity value from 24.0 nm to 10.7 nm in 3$\sigma$.TEX>.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.1
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• pp.1-8
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• 2004

According to the development of the Internet and the pervasion of Data Base, it is not easy to search for necessary information from the huge amounts of data. In order to do efficient analysis of a large amounts of data, this paper proposes a method for pattern classification based on the effective strategy for dimension reduction for narrowing down the whole data to what users wants to search for. To analyze data effectively, Radial Basis Function Networks based on VC-dimension of Support Vector Machine, a model of statistical teaming, is proposed in this paper. The model of Radial Basis Function Networks currently used performed the preprocessing of Perceptron model whereas the model proposed in this paper, performing independent analysis on VD-dimension, classifies each datum putting precise labels on it. The comparison and estimation of various models by using Machine Learning Data shows that the model proposed in this paper proves to be more efficient than various sorts of algorithm previously used.

• Journal of dental hygiene science
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• v.12 no.3
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• pp.259-269
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• 2012

This study examined in what category that the knowledge dimension and the cognitive processes dimension are described based on 'A revision o Bloom's taxonomy of educational objectives' in oral health education textbooks. Oral health education and practice from Educational Objectives of Dental Hygiene Department(Korea dental hygienist Prof Council, 2009) were selected to analyze a textbook, the body contents was analyzed in the knowledge dimension, and the activity was analyzed in cognitive processes dimension. Three experts were selected as a corder for reliable analysis. As a result of this study, the knowledge dimension in oral health education textbook was focused on the categories of factual knowledge and conceptual knowledge in textbook analysis based on 'A revision of Bloom's taxonomy of educational objectives', and the category dimension of 'understand' showed to be the most for the cognitive processes dimension. Moreover, there was no 'meta cognitive knowledge' that conforms to a higher-order thinking and the category dimensions of 'analyze', 'evaluate', and 'create' took very low proportion or did not exist. Conclusion, Oral health education textbooks were analyzed to fragmentary and Memorizing the level knowledge. Thus we have to develop oral health education textbooks reflected a variety of cognitive and knowledge dimension.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.2
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• pp.185-191
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• 2013

This paper presents a new method for roller design of IRB(isolation roller bearing) seismic isolation device using experimental evaluation. Three layered plate is adopted for the IRB in which the upper plate is placed on x direction and the lower plate is placed on y direction. The rollers placed in each plate make a plate movement. The roller is then optimally designed using variable geometric conditions. Stress distribution depends on the diameter and length of the roller and hence this is used for the determination of optimal geometry of the roller. In the experimental evaluation, it is observed that stress concentration at the end sides of roller is decreased and geometric coefficients depend on crowning dimension. In addition, in order to determine optimal design parameters of the roller the plastic deformation and friction are experimentally identified.

• ETRI Journal
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• v.42 no.1
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• pp.78-89
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• 2020

Human activity recognition (HAR) has become effective as a computer vision tool for video surveillance systems. In this paper, a novel biometric system that can detect human activities in 3D space is proposed. In order to implement HAR, joint angles obtained using an RGB-depth sensor are used as features. Because HAR is operated in the time domain, angle information is stored using the sliding kernel method. Haar-wavelet transform (HWT) is applied to preserve the information of the features before reducing the data dimension. Dimension reduction using an averaging algorithm is also applied to decrease the computational cost, which provides faster performance while maintaining high accuracy. Before the classification, a proposed thresholding method with inverse HWT is conducted to extract the final feature set. Finally, the K-nearest neighbor (k-NN) algorithm is used to recognize the activity with respect to the given data. The method compares favorably with the results using other machine learning algorithms.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.96-103
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• 2002

The objective of this study is to adjust the roll gap fur the dimension accuracy of bar in hot bar rolling process considering roll wear. In this study hot bar rolling processes fur round and oval passes have been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental from and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the effects of thermal softening of DCI (Ductile Cast Iron) roll material according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering curve. The new technique developed in this study for adjusting roll gap can give more systematically and economically feasible means to improve the dimension accuracy of bar with full usefulness and generality.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.1
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• pp.56-62
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• 2003

The objective of this study is to adjust the roll gap for the dimension accuracy of bar in hot bar rolling process considering roll wear. In this study hot bar rolling processes for round and oval passes have been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental form and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the effects of thermal softening of DCI (Ductile Cast Iron) roll material according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering curve. The new technique developed in this study for adjusting roll gap can give more systematically and economically feasible means to improve the dimension accuracy of bar with full usefulness and generality.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.6
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• pp.101-109
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• 2012

Silt curtains are constructed for minimizing pollution of sediment dispersion in water bodies. In spite of wide uses of the silt curtains, there are few studies for analyzing the effectiveness of them with respect to their dimension and hydraulic characteristics. Currently, the market of silt curtains does not provide the various dimension of them due to the limit of information regarding its effectiveness on reducing sediment pollution. In this study, a series of experiments were conducted to investigate hydraulic characteristics around the silt curtains under the different flow conditions. For this study, a silt curtain was fabricated and an open channel with 30cm of width and 40cm of depth was used. The results indicated that the silt curtain was not effective in preventing dispersion at flow velocities over 0.5m/s in real conditions. Based on the experimental results, it is required that approaching velocity should be minimized and the weight of bottom be increased in order to reduce deformation. The results of this study will provide information required to design appropriate dimension of silt curtains in various water environment such as velocity and water depths.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.1036-1041
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• 1997

The objective of this study is to adjust the roll gap for the dimension accuracy of bar in hot bar rolling process considering roll wear. In this study hot bar rolling processes for round and oval passes have been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental form and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the effects of thermal softening of DCI (Ductile Cast Iron) roll material according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering curve. The new technique developed in this study for adjusting roll gap can give more systematically and economically feasible means to improve the dimension accuracy of bar with full usefulness and generality.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.986-994
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• 2005

This Paper proposes the likelihood-based nonlinear dimension reduction method of the speech feature parameters in order to construct the voice activity detecter adaptable in noisy environment. The proposed method uses the nonlinear values of the Gaussian probability density function with the new parameters for the speec/nonspeech class. We adapted Likelihood Ratio Test to find speech part and compared its performance with that of Linear Discriminant Analysis technique. In experiments we found that the proposed method has the similar results to that of Gaussian Mixture Models.