• 한국의류학회지
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• 제30권5호
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• pp.699-710
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• 2006

The objective of this study was to identify the texture-related components of woven fabrics and to develop a multidimensional perceptual structure map to represent the tactile textures. Eighty subjects in clothing and tektite industries were selected for multivariate data on each fabric of 30 using the questionnaire with 9 pointed semantic differential scales of 20 texture-related adjectives. Data were analyzed by factor analysis, hierarchical cluster analysis, and multidimensional scaling(MDS) using SPSS statistical package. The results showed that the five factors were selected and composed of density/warmth-coolness, stiffness, extensibility, drapeability, and surface/slipperiness. As a result of hierarchical cluster analysis, 30 fabrics were grouped by four clusters; each cluster was named with density/warmth-coolness, surface/slipperiness, stiffness, and extensibility, respectively. By MDS, three dimensions of tactile texture were obtained and a 3-dimensional perceptual structure map was suggested. The three dimensions were named as surface/slipperiness, extensibility, and stiffness. We proposed a positioning perceptual map of fabrics related to texture naming system(TNS). To classify the textural features of the woven fabrics, hierarchical cluster analysis containing all the data variations, even though it includes the errors, may be more desirable than texture-related multidimensional data analysis based on factor loading values in respect of the effective variables reduction without losing the critical variations.

• 한국치위생학회지
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• 제15권1호
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• pp.111-118
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• 2015

Objectives: The aim of the study is to investigate the health belief model affecting the oral health behavior in middle and high school students. Methods: The subjects were 296 middle and high school students in Seoul, Gyeonggi and Incheon from February 15 to March 21, 2014. The students filled out the self-reported questionnaires after receiving informed consents. The instrument was adopted and revised from those of Kim & Hwang, and Choi & Joo. The questionnaire consisted of 4 questions of general characteristics, 9 questions of oral health status including subjective oral health status, frequency of tooth brushing, duration of tooth brushing, method of tooth brushing, use of oral health devices, dental clinic visit, scaling services, snack intake, and smoking. The oral health belief consisted of 25 questions including susceptibility, seriousness, barriers, benefit, and self-efficacy using Likert 5 scale. The reliability of Cronbach's alpha in the study was 0.725. Data were analyzed using SPSS ver 18.0 for frequency analysis, t-test, ANOVA, ${\chi}^2$-test, and Pearson's correlation coefficient, simple regression, and binary logistic regression. Results: Oral health beliefs of middle and high school students affected the oral health behaviors. Susceptibility, barriers and self-efficacy also influenced on the oral health behaviors. In order to provide the best oral health education, susceptibility and self-efficacy are the primary factors to increase motivation because the motivation endows the students with correction of oral health behaviors that improve the knowledge, attitudes, and decrease barriers in oral hygiene. Conclusions: It is important to correct oral health behaviors in the middle and high school students by providing the continuing and systematic oral health education.

• 한국치위생학회지
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• 제14권4호
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• pp.547-553
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• 2014

Objectives : This research aims to analyze the relationship between the state of mental illness and oral health management of mental patients in mental health care institutions. Methods : The data were randomly selected from 474 patients in mental health care institutions. and analyzed by SPSS WIN 12.0 program. Results : Schizophrenia accounted for 79.5%(337 patients) ; alcohol dependency, 5.3%(25 patients) ; mental retardation, 2.7%(13 patients) ; mental development disorder, 3.0%(14 patients) ; mental delusion and dementia, 7.6%(36 patients). Those who were in 40s had the highest dental caries of 3.95 and the highest remaining teeth of 26.76 were shown in the 20s. The correlation between remaining teeth and mental retardation was the highest, measuring 22.38(p<.05). Those who were in 70s had the serious periodontal condition that accounted for 41.3%(12 patients)(p<.05). The correlation coefficient for all factors-dental caries, remaining teeth, need for scaling, and periodontal condition-between mental illness condition and oral health were all positive(p <.05). The regression analysis resulted in the formula Y(mental health condition)=2.999+0.166(dental aries)-0.028(remaining teeth). Conclusions : Those who had mental illness had very poor and serious dental caries and periodontal diseases, so it is necessary to manage the dental health care for the mentally ill patients.

• 전산구조공학
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• 제8권3호
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• pp.113-122
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• 1995

이 논문의 목적은 현행법규(Uniform Buidling Code, NEHRP 설계규준 등)에 따라 설계된 구조들의 성능 및 안정성을 평가하는데 있다. 구조물의 내진성능은 신뢰성으로 표현할 수 있다. 구조물의 그의 수명동안 내진에 대한 신뢰성 해석을 하기 위해서는 주어진 구조물들의 많은 양의 동적반응 해석을 요구하는 것이 일반적이다 따라서 구조물의 신뢰성 해석을 위하여 구조물이 위치한 지역에 많은 양의 지진기록들이 요구된다. 이 논문에서는 인위적인 지진들(artificial earthquakes)을 부정착 임계 파정법(nonstationary randon process)을 이용해 만들었고 구조물은 Uniform Building Code와 AISC 허용응력 설계지침서(AISC allowables stress design manual)에 따라서 설계하였다. 이 논문에서는 주어진 지진하중에 대한 구조물의 반응은 구조물의 비선형 반응해석과 반응변위수정계수들을 이용한 간략화된 동위 구조물 해석(ENS)으로 얻었다. 이 논문에서는 구조물의 내진성능을 평가하였다. 또한 동위구조물(Equivalent Nonlinear System (ENS))을 이용한 해석과 구조물의 비선형 반응해석의 결과들을 비교하여 동위구조물을 이용한 방법의 정확성도 령가하였다.

• 한국재료학회지
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• 제23권10호
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• pp.550-554
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• 2013

As continued scaling becomes increasingly difficult, 3D integration has emerged as a viable solution to achieve higher bandwidths and good power efficiency. 3D integration can be defined as a technology involving the stacking of multiple processed wafers containing integrated circuits on top of each other with vertical interconnects between the wafers. This type of 3D structure can improve performance levels, enable the integration of devices with incompatible process flows, and reduce form factors. Through silicon vias (TSVs), which directly connect stacked structures die-to-die, are an enabling technology for future 3D integrated systems. TSVs filled with copper using an electro-plating method are investigated in this study. DC and pulses are used as a current source for the electro-plating process as a means of via filling. A TiN barrier and Ru seed layers are deposited by plasma-enhanced atomic layer deposition (PEALD) with thicknesses of 10 and 30 nm, respectively. All samples electroplated by the DC current showed defects, even with additives. However, the samples electroplated by the pulse current showed defect-free super-filled via structures. The optimized condition for defect-free bottom-up super-filling was established by adjusting the additive concentrations in the basic plating solution of copper sulfate. The optimized concentrations of JGB and SPS were found to be 10 and 20 ppm, respectively.

• Journal of Periodontal and Implant Science
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• 제38권1호
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• pp.23-30
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• 2008

Purpose: The purpose of this study was to investigate the incidence of curet fracture and its contributing factors. Material and Methods: Fifty-eight periodontal curets which were broken during periodontal treatment in Kangnung National University Dental Hospital for 1 year were used as study materials. The blade thickness of new curets and broken ones was measured using a digital micrometer. Types of treatment procedures, clinical experience of operators, point of breakage, and method of removal of broken fragments were recorded for each broken curet. Results: The incidence of curet fracture in root planing (16.4 curets per 1,000 procedures) was higher than those in flap surgery (7.5) or supragingival scaling (2.7). No curet was broken during supportive periodontal treatment. The incidence of fracture did not seem to be related with clinical experience of operators. The most frequent breakage point of the curets were upper 1/3 of blades. Fifty-six of 58 broken fragments were removed by non-surgical methods. Two broken tips which could not removed non-surgically were left in the pockets, and proved to be removed spontaneously 1 week later. Conclusion: Root planing showed higher incidence of curet fracture than any other type of periodontal treatment. Most of the fractured fragments were removed by non-surgical method. Further study is needed to develop methods of removal of the fragments which can not be removed non-surgically.

• 한국지반공학회논문집
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• 제20권9호
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• pp.91-103
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• 2004

지반-유체-구조물 시스템에 대한 1g 진동대 실험을 위한 상사법칙의 유효성을 검증하기 위하여 일련의 모형실험을 수행하였다. 크기가 서로 다른 3가지의 모형에 대한 실험결과 분석에는 lai가 제안한 상사법칙뿐만 아니라 과잉간극수압 발생을 위한 정상상태개념도 적용하여 각 크기의 모형이 예측하는 안벽시스템의 거동을 서로 비교하였다. 그 결과, 가속도와 과잉간극수압, 그리고 변위 응답의 경우, 가장 작은 모형벽체와 가장 큰 모형벽체는 비슷한 값을 예측한 반면, 중간크기의 모형벽체는 공진현상으로 인해 엉뚱하게 큰 값을 예측하였다. 또한 벽체의 수직침하와 회전각은 모형의 크기와 관계없이 모형벽체시스템의 크기가 증가할수록 증가하는 경향을 나타내었다.

• 전기학회논문지
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• 제58권2호
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• pp.391-398
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• 2009

In this study, we introduce the design methodology of an optimized fuzzy cascade controller with the aid of hierarchical fair competition-based genetic algorithm(HFCGA) for ball & beam system. The ball & beam system consists of servo motor, beam and ball, and remains mutually connected in line in itself. The ball & beam system determines the position of ball through the control of a servo motor. The displacement change the position of ball leads to the change of the angle of the beam which determines the position angle of a servo motor. Consequently the displacement change of the position of the moving ball and its ensuing change of the angle of the beam results in the change of the position angle of a servo motor. We introduce the fuzzy cascade controller scheme which consists of the outer(1st) controller and the inner(2nd) controller as two cascaded fuzzy controllers, and auto-tune the control parameters(scaling factors) of each fuzzy controller using HFCGA. The inner controller controls the position of lever arm which corresponds to the position angle of a servo motor and the outer controller decides the set-point value of the inner controller. HFCGA is a kind of parallel genetic algorithms(PGAs), and helps alleviate the premature convergence being generated in conventional genetic algorithms (GAs). For a detailed comparative analysis from the viewpoint of the performance results and the design methodology, the proposed method for the ball & beam system which is realized by the fuzzy cascade controller based on HFCGA, is presented in comparison with the conventional PD cascade controller based on serial genetic algorithms.

• 한국컴퓨터정보학회논문지
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• 제15권5호
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• pp.13-21
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• 2010

도립진자 시스템에서 칼만 필터링 최적의 결과를 얻기 위해서는 잡음 공분산 행열 Q, 측정잡음 공분산 행열 R과 초기 에러 공분산 행열 $P_0$와 같은 인자가 필요하다. 이러한 인자는 실제 상황에서 근사화된 값을 사용하거나 정확한 값을 알 수 없기 때문에 칼만 필터의 최적화에 영향을 미치지 않거나 이러한 공분산 행열의 스칼라 이득변화에 덜 민감한 경우를 연구의 대상으로 하고 있다. 또한 상태 측정시 에러를 예측하는 방법으로 구해진 에러 공분산 행열은 상태측정 값 보다는 공분산 행열의 이득과 연관성을 가지게 된다. 따라서 3가지 공분산 행열과 칼만 이득 그리고 에러 공분산 행열 간의 상관관계가 잡음인자인 스칼라 이득과의 연관성을 해석하고자 하였다. 본 연구는 3절에서 도립진자 시스템 모델을 간략하게 정리를 하였고 4절에서는 이러한 모델을 기반으로 하여 컴퓨터 시뮬레이션을 위한 도립진자 시스템에 대한 수학적 동적모델을 구성하고 5절에서는 이러한 인자와 스칼라 이득 값을 이용한 다양한 시뮬레이션 결과를 통하여 잡음인자의 연관성을 해석하였다.

• 한국지진공학회논문집
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• 제24권5호
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• pp.197-209
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• 2020

Evidence of liquefaction during the 2017 Pohang earthquake has highlighted the urgent need to evaluate the current seismic design standard for liquefaction in Korea, particularly the liquefaction triggering standard. With the simplified method, which is the most popular method for evaluating liquefaction triggering, the factor of safety for liquefaction triggering is calculated via the cyclic stress ratio (CSR) and the cyclic resistance ratio (CRR). The parameters in the CSR and CRR have undergone changes over time based on new research findings and lessons learned from liquefaction case-histories. Hence, the current design standard for liquefaction triggering evaluation in Korea should also reflect these changes to achieve seismic safety during future earthquakes. In this study, liquefaction susceptibility criteria were discussed initially and this was followed by a review of the current liquefaction triggering codes/guidelines in other countries and Korea. Next, the parameters associated with the CSR such as the maximum ground acceleration, stress reduction factor, magnitude scaling factor, and overburden correction factor were discussed in detail. Then, the evaluation of the CRR using the SPT N-value and CPT qc-value was elaborated along with overburden and clean-sand correction factors. Based on this review of liquefaction triggering evaluation standards, recommendations are made for improving the current seismic design standard related to liquefaction triggering in Korea.