• Korean Journal of Human Ecology
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• v.17 no.1
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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.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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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.

• English Language & Literature Teaching
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• v.15 no.4
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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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.801-808
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• 2018

The learning of the linear regression model is stable on the assumption that the sample size is sufficiently larger than the number of explanatory variables and there is no serious multicollinearity between explanatory variables. In this study, we investigated the difficulty of model learning when the assumption was violated by analyzing a real heavy rain damage data and we proposed to use a principal component regression model or a ridge regression model after integrating data to overcome the difficulty. We evaluated the predictive performance of the proposed models by using the test data independent from the training data, and confirmed that the proposed methods showed better predictive performances than the linear regression model.

• Journal of the Korean Society of Safety
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• v.31 no.4
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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.

• Journal of Navigation and Port Research
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• v.32 no.3
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• pp.207-213
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• 2008

Ship-handling simulation system has been used for maritime traffic safety assessment for harbor and fairway. There exist various environmental conditions under which ship may navigate along a fairway or in harbor. Due to the time and budget limitations, however, ship-handling simulations are usually carried out for very limited number of environmental conditions. In this paper, statistical method for effective and systematic determination of real time simulation conditions is suggested and applied to the maritime traffic safety assessment problems. In the empirical study, the principal component analysis method and the concept of empirical cumulative distribution function are suggested to estimate synthetic navigational difficulty and to select simulation conditions which would impose high difficulty on shiphandling.

• 대한공업교육학회지
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• v.44 no.1
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• pp.114-140
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• 2019

The purpose of this research is to analyze a principal's job at a Vocational High School using DACUM Task Analysis Method. The contents of this research are to set the order after deriving the duties and tasks of the principal., then to verify as the importance, difficulty, and frequency of each task, and also to indicate whether it is an essential capability to have in the early stages of one's duty. Finally, based on the job analysis results, a DACUM chart was developed by the principal of the Vocational High School. The DACUM Task Analysis Workshop was attended by one DACUM analyst with LEVEL - 1 license, seven DACUM members with more than four years experience, one secretary and two administrative assistants for a two-day period. The results of the research are as follows; First, the Vocational High School Principal is defined as a school administrator who operate the vocational education curriculum of in the specialized and customized high schools of industrial demand development and the job area. The analysis derived 11 duties and 95 tasks of the Principal. Second, the importance, difficulties, and frequency of each task were divided respectively into high (A), moderate (B), and low (C), and the consensus of the experts was made to determine whether the core capabilities are acquired early on the job. Third, based on the analysis results, a DACUM Task Analysis chart of the Vocational High School principals was presented. In addition, while engaged on the job of the vocational high school principal, a list of 49 general knowledge and abilities, 16 tools, Integrated data and fixtures are required. Along with 28 attitudes 33 future prospects and characteristics of the Vocational High School principal was presented.

• Proceedings of the KIEE Conference
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• 2006.10d
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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.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.3
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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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• v.4
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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.