• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1583-1593
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• 2002

This paper discusses the model validation and vibration suppression of an AMB flexible rotor via additional LQG controller. The main difficulty in the vibration suppression of the flexible rotor using AMB is to realize a controller that can minimize resonance without injuring the stabilized rigid modes. In order to solve this problem, simple scheme for system modeling and controller design are developed. Firstly, the AMB flexible rotor is stabilized with a PID controller, which leads to a new stable rotor-bearing system. Then, authors propose the model validation procedure using measured open-loop frequency responses to obtain an accurate model of the AMB flexible rotor system. After that, LQG controller with modal weighting is designed to suppress resonances of the stable rotor-bearing system. Due to the poor controllability and observability of flexible modes compared to rigid ones, balancing of two Gramians is prerequisite for the fair LQG controller design. Simulation with step disturbance and experimental results of unbalance response up to 10,000 rpm verified the effectiveness of the proposed scheme.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.626-631
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• 2002

This paper describes the weldability and mechanical behavior of JIS S45C medium carbon steel (corresponding to KS SM45C and SAE 1045) for machine structures in CW Nd:YAG laser welding. ill general, medium carbon steels have a limited application to the industrial fields in spite of good mechanical characteristics. This is due to welding difficulty because of the high carbon contents and impurities in this material. Therefore, in this study the laser weldability of medium carbon steel with adjusted contents of S and P has been investigated in order to extend the application to medium carbon steels. Several experiments and numerical simulations have been conducted to determine the characteristics of mechanical behavior in CW Nd:YAG laser welds. The results of the simulations concur with the experiment results. From the result of this study, the application possibility of CW Nd:YAG laser welding to medium carbon steel has been confirmed. Also, the appropriateness of mechanical behavior simulation has been verified to analyze and predict the welding phenomena.

• The Journal of Korean Academic Society of Nursing Education
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• v.15 no.1
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• pp.5-14
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• 2009

Purpose: The purpose of this study was to develop clinical education of Oriental Nursing. Methods: The subjects were one hundred and ninety-three students who have completed clinical practice. The questionnaires were composed of experience type and Oriental Nursing practices(25 items), level of satisfaction(20 items), difficulty level of practices(6 items), and preparation level of practice instructor(5 items). The reliability were Chronbach's $\alpha$=.84, .86, .74, and .93 respectively. Frequencies, percentage, t-test, and Pearson's Correlation was used in data analysis using SPSS PC+ 11.0. Results: Nursing students recognized that they had difficulties caused by a lack of knowledge of Oriental medicine, of learning the uniqueness of the nurse's role and lack of nurse's enthusiasm in teaching students. However, they were confident in preparing acupuncture and implementing Moxibustion, large Moxibustion, Bu-Hang therapy, aroma therapy and on administration of medicines and control of temperature of the medicines, exercise and rehabilitation. Therefore, instructors should train nursing students by developing a unique Oriental Nursing practice and reinforcement of nurses' independent and cooperative roles through the acquisition of Oriental Medical knowledge and terminology. It is necessary that they develop an educational program based on Oriental Nursing practice, perform consistently within the program and train its teaching faculty and instructors.

• Journal of Korean Academy of Nursing
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• v.44 no.2
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• pp.129-138
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• 2014

Purpose: To develop a Critical Thinking Skill Test for Nursing Students. Methods: The construct concepts were drawn from a literature review and in-depth interviews with hospital nurses and surveys were conducted among students (n=607) from nursing colleges. The data were collected from September 13 to November 23, 2012 and analyzed using the SAS program, 9.2 version. The KR 20 coefficient for reliability, difficulty index, discrimination index, item-total correlation and known group technique for validity were performed. Results: Four domains and 27 skills were identified and 35 multiple choice items were developed. Thirty multiple choice items which had scores higher than .80 on the content validity index were selected for the pre test. From the analysis of the pre test data, a modified 30 items were selected for the main test. In the main test, the KR 20 coefficient was .70 and Corrected Item-Total Correlations range was .11-.38. There was a statistically significant difference between two academic systems (p=.001). Conclusion: The developed instrument is the first critical thinking skill test reflecting nursing perspectives in hospital settings and is expected to be utilized as a tool which contributes to improvement of the critical thinking ability of nursing students.

• The Journal of Korean Academic Society of Nursing Education
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• v.22 no.4
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• pp.452-461
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• 2016

Purpose: This study was conducted to investigate the relationships among communication competence, professional self-concept, and stress in clinical practice of nursing students. Methods: The study participants were 308 senior year nursing students in D city and K province. Collected data were analyzed using t-tests, analysis of variance, Pearson's correlation coefficient, and stepwise multiple regression with the SPSS Version 20.0. Results: There were significant differences in participants' stress of clinical practice based on their level of satisfaction on clinical practice, self-confidence of nursing and difficulty with relationships in clinical practice. A negative correlation was detected between stress in clinical practice and the professional self-concept of nursing students. Significant predictors of the perceived stress of clinical practice were satisfaction in clinical practice and pride in nursing. These accounted for 18% of the perceived stress of clinical practice in a regression model. Conclusion: The results may serve as basic data in support of the need to the develop effective systematic stress management programs and clinical training courses in order to attenuate the stress experienced during clinical practice of nursing students.

• Korean Journal of Childcare and Education
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• v.16 no.2
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• pp.89-118
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• 2020

Objective: The purpose of this study is to conduct maker-education for prospective child care teachers explore changes and for the results to be used as a basic data to study the utilization of maker-education. Methods: To that end, 36 prospective child care teachers attending nursery school applied to the maker-education program and to the curriculum of children's literature and play. The collected interview materials and student journals were qualitatively analyzed. Results: The results showed that prospective child care teachers started with mixed expectations and but then actively participated in worries classes with interest and had fun. Also, in the stage of sharing, they changed from having difficulty communicating with colleagues to developing an attitude of cooperation and unity through communication. In addition, it has been shown that from feeling the difficulties of planning, planning changes and modifications are directly related to their development and that they are quickly and wisely dealt with. Conclusion/Implications: It is recognized that there is a need for a follow-up study to verify the effect of this as meaningful implications are derived from the effects of positively accepting feedback, planning to attempt a step-by-step approach, and active attitude toward communication between colleagues.

• Journal of Korean Elementary Science Education
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• v.39 no.4
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• pp.522-532
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• 2020

The aims of this study were to do a survey on teachers' perception and operational state for elementary science online remote classes and suggest ways to improve the elementary science online remote classes. The survey was based on responses from 100 teachers who have taught elementary science online remote classes for the first semester of 2020 for COVID-19. The questionnaire used in this study consisted of four parts: general informations of participants, the operation status of elementary science online remote classes, teachers' perceptions on the operation of elementary science online remote classes, ways to improve elementary science online remote classes. As a result of this study, elementary teachers taught elementary science online remote classes on the main use of content utilization type. And they had a difficulty in conducting elementary science online remote classes because of lack of contents, absence of elementary science online remote classes teaching methods, learner management and heavy workload. Therefore, to improve elementary science online remote classes the Ministry of Education and regional offices of education have to develop and provide high-quality contents reflect the characteristics of elementary science subjects, introduce a rent-an-experiment equipment system, and build a science class platform providing frequent real-time interaction between teacher and student.

• Journal of the Korean Home Economics Association
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• v.31 no.3
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• pp.187-197
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• 1993

The objectives of this study were to investigate university students' knowledge of traditional dishes and seasonal festive foods, and to estimate the level of consumption in Korea. The result of the study indicated that their level of knowledge of the seasonal festive foods was very low on as average. The reason was that, because each family prepared only one or two festive dishes on seasonal festival days, these students had few opportunity of being acquainted with other kinds of festive foods. In case of traditional foods university students ate some traditional foods. However, they age other kinds of traditional foods such as Jun-Gol and San-Juk less than once a month because of the difficulty in cooking these foods everyday. Finally, the students showed their intention to eat more traditional foods and festive foods if they can find these types of foods easily. The findings of this study suggested that, in order to increase the consumption of our traditional foods, it is necessary to encourage the establishment of many traditional food stores and to provide an easy access to these stores. Furthermore, every effort should be made to develop various kinds of food materials and easy recipes which can be used at home.

• Journal of the Korea Computer Industry Society
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• v.3 no.8
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• pp.1007-1018
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• 2002

A systematic and multi-dimensional analysis in evaluation results may play a role of providing both learners and instructors with essential information. Conventional types of evaluation research have a tendency of partiality for developing evaluation tools, and analyzing the evaluation results has mostly been fragmentary and a one-dimensional analysis. In this study, through analyzing evaluation results in a multi-dimensional way, a multi-dimensional evaluation result analyzing system was developed for the purpose of providing various information for both learners and instructors to accomplish quality learning teaching. Dimensions are classified into four dimensions including period, student, difficulty degree, and evaluation domain. Analysis results are presented in various types of Dcube, graphs, and spreadsheets.

• Journal of the Korean School Mathematics Society
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• v.2 no.1
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• pp.231-242
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• 1999

The focus of this development program is to input multimedia materials into learning according to the trend of recent social changes and to maximize the learning effect for improving problem-solving by offering familiar teaching materials. The expecting effects of this study are as follows: 1. This program helps students acquire mathematical concepts and principles about circular equation through concrete examples using a variety of media - text, voice, sound, and animation and so on - , makes it possible individual learning which was difficult for students to expect at the existing multitude class as progressing learning each unit on the screen and the perfect learning by offering FEED BACK 2. This program varied the difficulty of learning contents to learn according to learning abilities of learners by using animation and making the most of merits of computer and was able to improve learning effect by studying in a mutual way with managing learning procedure nonsuccessively. 3. Class using CAI program about developed circular equation unit has a positive effect on improving problem-solving by becoming from teacher centered class to student centered one. 4. This program makes students understand the contents of auxiliary learning in multimedia computer more efficiently, and cultivate abilities to adopt in accordance with changes in the future society by forming familiar computer mind.