• 응용통계연구
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• 제30권5호
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• pp.747-757
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• 2017

본 논문은 다변량 실현 변동성 계산에서 주기 선택 방안에 대해 연구하고 있다. 고빈도(high frequency) 시계열 자료에 기초한 일간 변동성인 실현변동성을 계산하고 차원 축소 방법인 주성분을 도입하였다. Cholesky 모형을 포함한 다양한 다변량 변동성모형을 주성분을 통해 비교하였으며 KOSPI/삼성전자/현대차 고빈도 수익률 자료를 이용하여 예시하였다.

• 한국실내디자인학회논문집
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• 제15권3호
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• pp.173-183
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• 2006

Design is inseparably related to aesthetics. In spite of that, it is difficult to explain the precise aesthetic variables that affect the aesthetic value of space or environment. Therefore, this study intended to find the relationships between aesthetic variables by perceptual and affective judgement for space design with focus on complexity and preference variables. The research found low level of 'arousing' as well as high levels of affective dimension variables 'pleasant' and 'relaxing' evoked high preference. High preference also appeared in space design cases with high unity, order, and clarity with low contrast and complexity, which are variables of perceptual dimension. Complexity, one variables of preference by Kaplan, is in an inverse proportion to space preference. Thus, space design with high complexity has high level of 'exciting' and 'arousing' affective responses and relatively low level of 'relaxing' response. Additionally, it was confirmed that the most importantly influential factor on complexity was diverse components rather than visual richness and ornamentation.

• 국제초고층학회논문집
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• 제9권4호
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• pp.307-314
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• 2020

High-rise buildings with vertical setback are widely used in practice. From the field investigation of the past earthquakes, it was found that such kind of vertically irregular high-rise building structures easily suffer severe damage during strong earthquakes. This paper presents an extensive study on the earthquake responses of moment-resisting frame structures (MFS) popularly applied in high-rise buildings with vertical setback. Four groups of MFS are designed, including three groups of structures with vertical setback and one group of structures with the lateral stiffness varying along the building height but without vertical setback. The numerical models of the structures are established, and the time history analysis of the structures under different levels of earthquakes is conducted. The earthquake responses of the structures are compared. The influence of the ratio between the horizontal setback dimension and the previous plan dimension, the eccentricity of setback, and the position where the setback occurs on the seismic performance of structures is studied. The rationality of the provisions for the structures with vertical setback specified in the current design codes is checked by the findings from this study.

• 정보처리학회논문지B
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• 제15B권4호
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• pp.285-292
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• 2008

색상 히스토그램은 영상의 색상 특징을 표현하기 위한 특징 벡터로 빈번히 사용되지만, 고차원의 특징 벡터를 생성하므로 효율성의 면에서 한계점을 갖고 있다. 본 논문에서는 주어진 차량 영상의 색상 히스토그램에 PCA (principal components analysis) 기법을 적용하여 특징 벡터의 차원을 축소시키는 방법을 제안한다. 차원이 축소된 특징 벡터들에 대해서는 SVM (support vector machine) 기법을 적용하여 차량 색상을 인식하기 위해 사용한다. 특징 벡터의 차원을 1/32로 축소한 결과, 차원이 축소되기 이전의 특징 벡터와 비교하여 약 1.42%의 미소한 차이로 색상 인식 성공률이 감소하였다. 또한, 색상 인식의 수행 시간은 1/31로 단축됨으로써 효율적으로 색상 인식을 수행할 수 있었다.

• 제어로봇시스템학회논문지
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• 제22권9호
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• pp.710-715
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• 2016

Due to its simplicity and high reliability, the box-counting(BC) method is one of the most frequently used techniques to estimate the fractal dimensions of a binary image with a self-similarity property. The fractal calculation requires data sampling that determines the size of boxes to be sampled from the given image and directly affects the accuracy of the fractal dimension estimation. There are three non-overlapping regular grid methods: geometric-step method, arithmetic-step method and divisor-step method. These methods have some drawbacks when the image size M becomes large. This paper presents a BC algorithm for enhancing the accuracy of the fractal dimension estimation based on a new sampling method. Instead of using the geometric-step method, the new sampling method, called the coverage ratio-step method, selects the number of steps according to the coverage ratio. A set of experiments using well-known fractal images showed that the proposed method outperforms the existing BC method and the triangular BC method.

• 간호행정학회지
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• 제12권1호
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• pp.131-139
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• 2006

Purpose: This study was carried out to understand the degree of moral distress of nurses and to provide scientific data for searching measures to efficiently manage their moral distress. Method: The survey was conducted with 302 nurses at the general hospital in City D by using the self-report type of questionnaire composed of 66 questions of 5-point Likert scale in four dimensions. Result: The mean scores of moral distress of nurses showed higher than average in all four dimensions: $80.54{\pm}14.82$ of 150 in the situational dimension, $52.99{\pm}9.98$ of 90 in the cognitive dimension, $13.30{\pm}2.85$ of 25 in the behavioral dimension, and $48.06{\pm}7.76$ of 65 in the emotional dimension. In addition, moral stress of each factor in the situational area showed $34.20{\pm}7.27$ in negative medical behavior, $10.98{\pm}2.53$ in lack of respect for autonomy of patients, excessive economic burden $10.86{\pm}2.94$, $7.40{\pm}1.89$ in irrational organizational administration and $17.10{\pm}3.50$ in negative nursing behavior. Conclusion: It is necessary to develop the intervention program to help nurses to reduce their moral distress since its degree showed considerably high.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1308-1311
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• 2004

It is very important that get polishing characteristic that to be stable that accomplish planarization of high efficiency in chemical mechanical polishing, and there is repeatability Groove of pad causes much effects in flow of slurry among various factors that influence in polishing characteristic, is expected to cause change of lubrication state and polishing characteristic in contact between wafer and pad. Therefore, divided factors of pad groove by groove pattern, groove profile, groove dimensions. This research wishes to study effect that dimension of pad groove gets in polishing performance. When changed dimension (width, depth, pitch of groove) of groove, measured change of removal rate and friction force. According as groove dimension changes, could confirm that removal rate and friction force change. While result of this experiment studies effect of pad groove in CMP, it is expected to become small help.

• 한국수학교육학회지시리즈A:수학교육
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• 제55권4호
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• pp.397-416
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• 2016

This study analyzed the quality of mathematics classes with observations using the instrument, MQI(Mathematical Quality of Instruction). Class recordings and interviews were conducted on 2 pre-service teachers and 4 in-service teachers. This study recorded and analyzed 3 or 4 classes for each mathematics teacher by using revised MQI. There were a total of 8 raters: 2 or 3 raters analyzed each class. MQI has four dimensions: Richness of the Mathematics, Working with Students and Mathematic, Errors and Imprecision, Student Participation in Meaning-Making and Reasoning. In the dimension of 'Richness of Mathematics', all teachers had good scores of 'explanations of teacher' but had lower scores of 'linking and connections', 'multiple procedures or solution methods' and 'developing mathematical generalizations.' In the dimension of 'Working with Students and Mathematics', two in-service teachers who have worked and having more experience had higher scores than others. In the dimension of 'Errors and Imprecision', all teachers had high scores. In the dimension of 'Student Participation in Meaning-Making and Reasoning', two pre-service teachers had contrast and also two in-service teachers who hadn't worked not long had contrast. Implications were deducted from finding to improving quality of mathematics classes.

• 한국의류산업학회지
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• 제18권5호
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• pp.647-657
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• 2016

This study investigated domestic and foreign cycle wear sizing systems for the domestic market and provided basic data for development of a high functional cycle wear with excellent fitness qualities. Each brand was found to have different dimension items and different sizes as well as size deviation and range according to each item. Therefore, a size selected by referring to the dimension items would be expected to have confusion when selecting a size. Domestic brands are able to selects sizes relatively easily because they suggest sizes mainly by height and weight (which are a universal size). However, the development of a sizing system for domestic cycle wear brands is needed because each brand have different sizes according to its dimension items. Foreign brands are also different from domestic brands in size marking items and sizes according to items. Therefore, the establishment of a sizing system standard for foreign brands is necessary because there could be a problem with fitness in the same sizes selected for domestic brands. Cycle wear is also able to cover various body types due to the elasticity of its material; however, and evaluation of fitness and a follow-up study will be necessary to develop cycle wear with a fitness that is proper for a Korean body type.

• Wind and Structures
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• 제29권6호
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• pp.389-403
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• 2019

In this study, two original spectral representations of stationary stochastic fields, say the continuous proper orthogonal decomposition (CPOD) and the frequency-wavenumber spectral representation (FWSR), are derived from the Fourier-Stieltjes integral at first. Meanwhile, the relations between the above two representations are discussed detailedly. However, the most widely used conventional Monte Carlo schemes associated with the two representations still leave two difficulties unsolved, say the high dimension of random variables and the incompleteness of probability with respect to the generated sample functions of the stochastic fields. In view of this, a dimension-reduction model involving merely one elementary random variable with the representative points set owing assigned probabilities is proposed, realizing the refined description of probability characteristics for the stochastic fields by generating just several hundred representative samples with assigned probabilities. In addition, for the purpose of overcoming the defects of simulation efficiency and accuracy in the FWSR, an improved scheme of non-uniform wavenumber intervals is suggested. Finally, the Fast Fourier Transform (FFT) algorithm is adopted to further enhance the simulation efficiency of the horizontal stochastic wind velocity fields. Numerical examplesfully reveal the validity and superiorityof the proposed methods.