• 한국생활과학회지
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• 제17권1호
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• pp.45-56
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• 2008

The purpose of this study was to provide data for the stress and difficulty of the principal on the day-care centers. For this purpose, we had interviewed with 154 principals on the day-care centers in Daejeon and Chungcheong-do. The principals reported that they had stress about administration of day-care center normally. Their stress was different by the type of the center, the number of the class and their sex. They had difficulties in administrating teachers, managing the center, relating with the authorized officials, and finances. For the governing their center expertly, they needed to improve the quality of teachers, to amplify the financial support, and so on.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.257-258
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• 1998

To reveal the interconnected brain regions involved in human working memory, their functional connectivity was analyzed using principal component analysis (PCA). rCBF PET scans were peformed on 5 normal volunteers during the verbal and visual working memory tasks and PCA was applied. PCA produced the first principal components related with the increase of the difficulty and the second one which demonstrate the dissociation of verbal and visual memory system.

• 영어어문교육
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• 제15권4호
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• pp.75-94
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• 2009

This study was designed to assess demotivation factors and compare the factor between two secondary school student groups. It furthermore examined how the factors related to students' L2 proficiency. A 31-item questionnaire was completed by 407 junior (JH) and senior high school (SH) students. Five factors were extracted through the principal axis factoring: Teachers' competence and teaching styles, Dissatisfaction with English classes and grading system, Difficulty of learning English, Lack of motivation and interest in learning English, and Inadequate learning contents. Although both JH and SH students did not perceive their English teacher as a strong attribution of demotivation, Difficulty of learning English and Dissatisfaction with English classes and grading system were the two strongest demotivating factors. When compared the overall mean scores of each factor between JH and SH groups, significant differences were found in all factors except Factor 4, with SH students reporting stronger demotivation. JH students attributed their demotivation to Difficulty of learning English, while SH students attributed that to Dissatisfaction with English classes and grading system. Both groups tended to attribute their demotivation to external forces. The study also showed that several demotivation factors related negatively to L2 proficiency.

• 대한토목학회논문집
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• 제38권6호
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• pp.801-808
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• 2018

선형회귀모형의 학습은 일반적으로 자료의 개수가 설명변수의 개수보다 충분히 크고, 설명변수들 사이에 심각한 다중공선성이 없다는 가정 하에서 안정적으로 이루어진다. 본 연구에서는 이러한 가정이 위배되었을 경우 모형 학습의 어려움을 실제 호우피해자료를 분석함으로써 조명하였고, 이를 해결하기 위해 자료를 통합한 다음 주성분회귀모형 또는 능형회귀모형을 사용할 것을 검토하였다. 모형의 학습에 사용된 자료와 별도의 독립된 자료에서 제안된 모형들의 예측력을 평가하였고, 제안된 방법이 선형회귀모형보다 더 나은 예측력을 보이는 것을 확인하였다.

• 한국안전학회지
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• 제31권4호
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• pp.35-41
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• 2016

In order to guarantee the process safety and prevent accidents, the deviations from normal operating conditions should be monitored and their root causes have to be identified as soon as possible. The statistical theories-based method among various fault diagnosis methods has been gaining popularity, due to simplicity and quickness. However, according to fault magnitudes, the scalar value generated by statistical methods can be changed and this point can lead to produce wrong information. To solve this difficulty, this work employs PCA (Principal Component Analysis) based method with qualitative information. In the case study of our previous study, the number of assumed faults is much smaller than that of process variables. In the case study of this study, the number of predefined faults is 19, while that of process variables is 6. It means that a fault diagnosis becomes more difficult and it is really hard to isolate a single fault with a small number of variables. The PCA model is constructed under normal operation data in order to get a loading vector and the data set of assumed faulty conditions is applied with PCA model. The significant changes on PC (Principal Components) axes are monitored with CUSUM (Cumulative Sum Control Chart) and recorded to make the information, which can be used to identify the types of fault.

• 한국항해항만학회지
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• 제32권3호
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• pp.207-213
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• 2008

항만이나 항로에서의 심층적인 선박운항 안전성 평가를 위한 목적으로 주로 선박운항 시뮬레이션 시스템이 사용되고 있다. 하지만, 실제 해상에서 선박이 조우할 수 있는 환경 조건은 매우 다양한 반면, 비용이나 시간적인 제약으로 인하여 실시간 선박운항 시뮬레이션은 극히 한정된 경우에 대해서만 수행되는 것이 일반적이다. 본 논문에서는, 이러한 실시간 시뮬레이션 실험 조건을 효과적이고 체계적으로 도출하기 위한 통계적 기법에 대하여 제안하고, 이 기법을 실제 선박 운항 안전성 평가를 위한 시뮬레이션 연구에 적용한 실증 분석 결과를 사례 연구로 기술하였다. 실증 분석에는 주성분을 이용한 종합 운항 난이도 산정 방법과 누적 확률분포 개념을 이용하여 선박 운항 난이도가 높은 실험 조건을 실시간 시뮬레이션 실험 조건으로 선택하는 기법을 제시하였다.

• 대한공업교육학회지
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• 제44권1호
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• pp.114-140
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• 2019

이 연구는 데이컴(DACUM) 직무 분석기법을 활용하여 직업계고 학교장의 직무를 분석한 연구이다. 연구의 내용은 직업계고 학교장의 직무를 구성하는 임무와 작업을 도출하고 각 임무에 작업의 순서를 정한 후, 작업별 중요도, 난이도, 수행 빈도를 밝히고, 입직 초기에 갖출 필수능력 인지의 여부를 구분하여 제시하는 것이다. 최종 직무분석 결과를 토대로 직업계고 교장의 DACUM 차트를 개발하였다. DACUM 직무분석을 위한 워크숍은 DACUM 분석가 1명, 현업내용전문가 위원 7명, 서기 1명, 실무자 2명으로 구성하여 이틀 동안 진행하였다. 연구 결과는 다음과 같다. 첫째, 직업계고 학교장의 정의는 특성화고 산업수요맞춤형고 등에서 산업수요인재양성의 직업교육과정을 운영하는 학교경영자이며, 직업계고 학교장의 직무 영역은 11개의 임무(duty)와 95개의 작업(task)이 도출되었다. 둘째, 직업계고 학교장의 임무별 작업마다 중요도, 난이도 및 수행 빈도를 정도에 따라 각각 높음(A), 보통(B), 낮음(C)으로 구분한 결과, 직업계고 학교장의 임무별 작업(95개)의 중요도는 A 84개, B 11개, 난이도는 A 58개, B 33개, C 4개, 수행 빈도는 A 18개, B 33개, C 44개이다. 학교장의 임무별 작업(95개) 중에서 입직 초기에 갖추어야 할 필수능력은 30개로 나타났다. 셋째, 직무분석 결과를 토대로 직업계고 학교장의 DACUM 직무분석 차트를 제시하였다. 또한, 직업계고 학교장의 직무를 수행할 때 요구되는 일반 지식과 능력 49개, 직무수행에 필요한 통합자료 및 비품 목록 16개를 도출하고, 작업자의 태도 28개와 직업계고 학교장의 장래 전망과 특성 33가지를 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.95-97
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• 2006

Cogging torque is often a principal source of vibration, noise and difficulty of control in BLDC motors. Therefore, this paper will present a design method of magnetization system with sinusoidal air-gap flux density distribution of Nd-Fe-B magnets in ring type for reduction of Vibration and Noise and low manufacturing cost.

• 대한산업공학회지
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• 제38권3호
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• pp.198-207
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• 2012

In product or process parameter design, the case of multiple performance characteristics appears more commonly than that of a single characteristic. Numerous methods have been developed to deal with such multi-characteristic parameter design (MCPD) problems. Among these, this paper considers three representative methods, which are respectively based on the desirability function (DF), grey relational analysis (GRA), and principal component analysis (PCA). These three methods are then used to solve the MCPD problems in ten case studies reported in the literature. The performance of each method is evaluated for various combinations of its algorithmic parameters and alternatives. Relative performances of the three methods are then compared in terms of the significance of a design parameter and the overall performance value corresponding to the compromise optimal design condition identified by each method. Although no method is significantly inferior to others for the data sets considered, the GRA-based and PCA-based methods perform slightly better than the DF-based method. Besides, for the PCA-based method, the compromise optimal design condition depends much on which alternative is adopted while, for the GRA-based method, it is almost independent of the algorithmic parameter, and therefore, the difficulty involved in selecting an appropriate algorithmic parameter value can be alleviated.

• International Journal of Costume and Fashion
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• 제4권
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• pp.113-130
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• 2004

Korea may have the social environment that has a high interest and demand for the fashion industry, but the relative importance that the Hanbok industry occupies in the fashion industry is very low. It can be found that this is attributed to the difficulty in identifying the trends of Hanbok due to the smallness of Hanbok material producers and Hanbok producers, a change in consumers' consciousness of Hanbok, the difficulty of ties and integration between Hanbok-related organizations, the lack of support from government and the like. Given the recent trend that the principal factor that enables the Korean fashion industry to be competitive in the world fashion business community is based on the beauty of Hanbok, this indifference to the Korean Hanbok industry would be the roadblock to internationalizing the Korean fashion industry. Accordingly, this study attempted to identify the problem of Hanbok-rela1ed department as the basic work for the development of the Hanbok industry and present the plan to activate it, thereby providing basic materials for exploiting the new arena of the Hanbok cultural industry the domestic and foreign fashion market in the 21st century.