• Journal of Power Electronics
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• v.14 no.4
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• pp.641-648
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• 2014

This paper presents the design considerations and analysis for an interleaved boundary conduction mode power factor correction buck converter. A thorough analysis of the harmonic content of the AC line current is presented to examine the allowable voltage gain (K value) for meeting the EN61000-3-2, Class D standard while maximizing efficiency. The results of the harmonic analysis are used to derive the required value of K and therefore the output voltage necessary to meet the class D requirements for a given AC line voltage. The discussed design consideration and harmonic current analysis are verified on a 300W universal line experimental prototype converter with an 80V output. The measured efficiencies remain above 96% down to 20% of the full load. The input current harmonics also meet the IEC61000-3-2 (class D) standard.

• Journal of Engineering Education Research
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• v.22 no.1
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• pp.22-28
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• 2019

The purpose of this study is to develop instructional design model of flipped learning suitable for engineering education field and to draw out effects and improvements by applying it to actual lessons for engineering college students. Literature review and case studies were conducted to achieve the purpose of the study. For a case study, flipped learning was applied to 'creative problem solving methodology' which is a liberal arts course of engineering college at D university in Gyeonggi-do. As a result of the literature review, the PARTNER model was applied and weekly instructional guide was presented by each stage. In addition, the results of analysis on the reflection journal showed that the students were more able to achieve the deepening learning stage through active participation in class than the existing class, and found that they had a more challenging plan after the class.

• Journal of Engineering Education Research
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• v.21 no.4
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• pp.28-34
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• 2018

Design class through team activities is increasing in engineering education. Team-based education has been known to improve students' creativity, problem solving ability, cooperative ability, self-directed learning ability, and communication ability. How to organize a team is an important issue that affects the performance of team activities as well as student satisfaction. However, previous studies have focused on the causal relationship between team formation and the team's performance. This paper deals with how to organize a balanced team in a real class. When the basic characteristic values of students are givens, the aim is to make the sum of the characteristic values as fair as possible for each team. We propose a mathematical team formation model and show how to apply it through case studies.

• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.53-56
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• 2007

In the response to the demand for electrical energy, much effort was given to develop and commercialize high temperature superconducting (HTS) power equipment has been made around the world. Especially, a HTS transformer is one of the most promising devices. Recently, Korea Polytechnic University and Gyeongsang National University are developing a power distribution and transmission class HTS transformer that is one of the 21st century superconducting frontier projects in Korea. For the development of 154 kV class HTS transformer, the cryogenic insulation technology should be established. We have been analyzed insulation composition and investigated electrical characteristics such as the breakdown of $LN_2$, barrier, kapton films, and the surface flashover of FRP in $LN_2$. Furthermore, we are going to compare with measured each value and apply the value to the most suitable insulating design of the HTS transformer.

• Journal of the Korean Society of Floral Art and Design
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• no.45
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• pp.47-56
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• 2021

It was applied by making the models such as the prior learning (e-learning), modeling by manual, learner's practice, 1:1 teaching coaching, self evaluation, coaching behavior assessment(primary, secondary), and self-directed practice. First, the cognitive practice education through the prior learning is very essential in the practice of floral design. Second, the practice class of floral design is a class where the professor generally set an example first, and the learners followed. Third, this study was to prepare the checklist, reflect it through the self evaluation, and prepare the evaluation form in accordance with the element, principle, and technical parts of floral design about the finished works. Fourth, contrary to the existing class completing within the class hour, the practice class is a process of trying to do self-directed practice, returning to home. Fifth, this study was to evaluate the works the learner made once again through the sketching and photographing by placing the work process of portfolio at the last step. To conclude, this study has found that such series of process through six steps on the practice form by the learner only would be excellent teaching learning model to improving the basic capacity of floral design. Accordingly, the development of teaching materials related to this and adaptation in the field in the future is considered as it will be very helpful to the learners' self-directed learning.

• Journal of Fashion Business
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• v.6 no.6
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• pp.43-55
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• 2002

This study intends to consider the characteristics of Tudorian costume and find out how the thoughts and cultures in those days had influences on the costume trends of low and middle class. In terms of the Tudorian costume which generated new cultural mainstreams along with blossomed civil culture, this study focuses on the characteristics and trends of costume at low and middle class, which have been little addressed in studies on western costume history or related fields, turning from the costume of upper class based on wealthy noblemen who showed off its dignity and authority along with jewelry and gorgeous ornamental craftsmanship. This study used related pictures, museum material and other literatures as its reference. It first looked into the general characteristics of western costume and considered the characteristics of costumes popularized in professionals at middle class such as apprentice, yeomen and low-class people. Professional or other middle class almost typically used to wear tunic, doublet, shirts, coat or long gown. Black was mainly used as clothes color. Similarly to upper class, silk or velvet was very often used as material. People at low class enjoyed wear costumes with simple and easy style for working. They also preferred natural color and cotton or wool as material. This study intended to find out which type of costumes people at low and middle class enjoyed wearing, rather than compare costume between such two classes.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.85-89
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• 2004

The paper presents a summary of the multidisciplinary/optimization method for the preliminary design of container feeder vessel. The current scenario in the ship building industry highly focuses on container ship design and construction proving the inherent demand in maritime industry. The design accomplishes the outer circle of the design spiral giving stress in areas of Hull Form Design, Resistance & Propulsion. Empirical relations, model test results, data from built ships, class rules and latest market demands stood as the criteria for the design. Optimization of the design as per the owners requirement. class rules, and the trade route selected are the major challenges met with. Strength. reliability, structural safety and stability have been incorporated in compromising standards.

• Journal of the Ergonomics Society of Korea
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• v.22 no.3
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• pp.45-56
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• 2003

This study was conducted to develop user interface design guidelines for those who design education software products (web sites or CD-ROM titles). To establish this guideline scheme, international standards, commercial design guidelines, and research papers were surveyed. Especially, ISO 9241 was referred as a basic model of a guideline scheme. First, the research group developed draft guidelines. After that, education software developers, designers, and a user group reviewed the draft and the draft was revised with their commentations. Five components were selected as a primary class of guideline scheme: general principle, dialogue design, user guidance, visual interface, and information presentation. Each component was divided several components as a secondary class. Finally, 45 items were selected as user interface design guidelines for the education software design.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.211-218
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• 2002

An entity-based integrated design product and process model uses product and process entities to describe design information and design activities, respectively. The concepts and notation for product and process entities in the entity-based integrated design model are similar to the concepts of object-oriented programming languages such as C++ and Smalltalk. This paper uses C++ to program an entity-based integrated design model for building frames structures. The design information and activities involved in the three dimensional building space, the locations of frames, and the grouping of frames represented as entities in the entity-based integrated design model are transformed to C++ codes. Each product or process entity can be basically transformed to an class. The attributes of an entity can be defined as variables and member functions of a class.

• Journal of Engineering Education Research
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• v.22 no.4
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• pp.71-77
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• 2019

Capstone design is a very important college course that enhances students' creativity and skills. However, in most universities, the operation of capstone design is operated by the experience and intuition of the advisor, and it is somewhat lacking in the generation of useful results such as patent rights and technology start-up from the capstone design result. In this study, we proposed a performance - based capstone design operation model through patent linkage so that the capstone design class can create creative and useful results. The proposed operating model includes support for research on prior art of patent information utilization, patent right of idea, and technology commercialization. The proposed operating model was directly applied to the capstone design class in the university, and it was confirmed that useful results such as expansion of the scope of the research achievement and technology start - up were created compared to the existing operation model.