• Journal of Drive and Control
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• v.15 no.1
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• pp.28-37
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• 2018

When the wind speed rises above the rated wind speed, the produced power of the wind turbines exceeds the rated power. Even more, the excessive power results in the undesirable mechanical load and fatigue. A solution to this problem is pitch control of the wind turbines. This paper presents a systematic design method of a collective pitch controller for the wind turbines using a discrete fuzzy Proportional-Integral (PI) controller. Unlike conventional PI controllers, the fuzzy PI controller has variable gains according to its input variables. Generally, tuning the parameters of fuzzy PI controller is complex due to the presence of too many parameters strongly coupled. In this paper, a systematic method for the fuzzy PI controller is presented. First, we show the fact that the fuzzy PI controller is a superset of the PI controller in the discrete-time domain and the initial parameters of the fuzzy PI controller is selected by using this relationship. Second, for simplicity of the design, we use only four rules to construct nonlinear fuzzy control surface. The tuning parameters of the proposed fuzzy PI controller are also obtained by the aforementioned relationship between the PI controller and the fuzzy PI controller. As a result, unlike the PI controller, the proposed fuzzy PI controller has variable gains which allow the pitch control system to operate in broader operating regions. The effectiveness of the proposed controller is verified with computer simulations using FAST, a NREL's primary computer-aided engineering tool for horizontal axis wind turbines.

• Journal of Korean Academy of Nursing
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• v.22 no.2
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• pp.143-156
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• 1992

This descriptive study explored the health and illness concepts of preschoolers to provide understanding on which to build research. The subjects were convenience sample three to six year of age attending one art institute in Cheju city. Data were collected through semistructured interviews by author, Children were asked to draw two figures, one healthy and one ill persons. The drawings were not analysed to grasp the meaning as in a projective technique, but only to relate to their response. Data were coded and categorized by content analysis. The results of this study are summarized as follows : 1) Three year olds responded with some unrelated answers but well to questions related to their experiences of illness ; older participants answered questions related health and illness concepts more easily. Generally the levels of subjects' responses did not differ according to age and sex. 2) Preschoolers' answers about the cause, treatment and prevention of illness, and the meaning and promotion of health were coded and then classificated to 9 categories, (food, obedience to authoritys physical function, presence or absence of illness or symptoms, hygiene. treatment, traumatic injury, rest and germs). Food and obeidence to authority categories were most frequent responses the food category was associated with obeidence to authority because it seemed that the children follow the orders of their parents or other authority figures to eat or not to eat something This result was compatible with that of previous studies that preschoolers perceived illness as possible punishment for misbehavior. Participants except for one four year old boy did not suggest that germs cause illness. The children perceived themselves and their families as healthy even though they had symptoms of illness. 3) Preschoolers' health and illness concepts were. influenced by their experiences and related to their development that rules derived from authority and if not complied with, will bring punishment. These oonceptualizations may be the disparity that they perceived themselves and their families as healthy even though they were ill. A previous study by Perrin and Gerrity suggested that the level of children's illness concepts correlated with that of their physical causality and was lower than it. But the levels of health and illness concepts in this sample higher than those of the physical causality.

• Journal of KIISE:Software and Applications
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• v.32 no.5
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• pp.385-395
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• 2005

Long sentence analysis has been a critical problem in machine translation because of high complexity. The methods of intra-sentence segmentation have been proposed to reduce parsing complexity. This paper presents the intra-sentence segmentation method based on maximum entropy probability model to increase the coverage and accuracy of the segmentation. We construct the rules for choosing candidate segmentation positions by a teaming method using the lexical context of the words tagged as segmentation position. We also generate the model that gives probability value to each candidate segmentation positions. The lexical contexts are extracted from the corpus tagged with segmentation positions and are incorporated into the probability model. We construct training data using the sentences from Wall Street Journal and experiment the intra-sentence segmentation on the sentences from four different domains. The experiments show about $88\%$ accuracy and about $98\%$ coverage of the segmentation. Also, the proposed method results in parsing efficiency improvement by 4.8 times in speed and 3.6 times in space.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5
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• pp.1559-1569
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• 2000

CHILL96 is recommended as development language for telecommunication systems by ITU-T. In this paper, we describe the design and implementation of CHILL96 compiler using C++ intermediate code. Translation rules from CHILL96 to C++ are designed for code generation. The CHILL96 compiler is composed of four parts such s syntax analyzer, visibility checker, semantic analyzer and code generator, and each part has very close relationship with symbol table and abstract syntax tree. Performance evaluation has been performed for feasibility study. After performance evaluation, we conclude the CHILL96 compiler using C++ intermediate sho good performance compared with other CHILL compilers. In addition to high performance and portability, the CHILL96 compiler using C++ intermediate code helps application developers to maintain and enhance telecommunications software by translating CHILL96 program to C++ program.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.78
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• pp.119-143
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• 2018

This research aims to review every important academic research on risk management in FTA and to suggest a future area for further research. This research area seems to focus on conceptual study or fact finding rather than on theory development or empirical research on causal relationship or theory testing. The National Assembly Digital Library analyzed the results of 3,576 researches on thesis and journals fromthe results of the FTA. Research on FTA is analyzed in four major themes. First, there have been previous studies on business performance such as FTA export performance and economic effect. Second, analyzed the effects of FTA in product and service. The products are classified into agricultural, marine products, manufacturing, textiles and clothing, medicinal pharmaceuticals, cosmetics, and others. Services are classified into educational and cultural contents, service industry and financial industry. Third, research on the risk management of FTA Origin is broadly classified into the use of country of origin and the verification of origin, and the use of origin includes the study of rules of origin and systems of origin and management. Origin verification was divided into origin verification and origin risk management. Fourth, study on the conclusion area of the FTA, studies were conducted on areas such as Korea-US FTA, Korea-China FTA, Korea-EU FTA, Korea-Japan FTA, Korea-Chile FTA, and Korea-ASEAN FTA. Search results through the FTA, focused on analyzing the FTA area and concept research by research purpose. In addition, research methods are mainly focused on documentary survey, and research areas are concentrated on specific countries such as China and USA. This implies a necessity for a future development in that research area. Other areas for future research may include case research on actual failures in FTA, proactive risk management strategy, and integrated risk management for export companies. Risk management in FTA may help investment expansion, and that is why research on the issue matters.

• School Mathematics
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• v.1 no.2
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• pp.637-660
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• 1999

Although ‘to understand mathematics’ is an important educational purpose, most student do not have a relational understanding of the basic concept of mathematics but have a instrumental understanding. This paper will investigate the possibility of using computers for enhancing relational understanding. In the ‘Qualitative case study’, three students who are in the first grade at E-High school took part in 7 activities during four weeks, and were later interviewed and engaged in informal discussion and were observed. This is the result of this study. 1. The three students were passive participants in mathematics problem solving situation at school. Therefore, student B just applied formulas which she had memorized, and student C would forgot the formulas occasionally. These common students needed to participate actively in doing mathematics. 2. The activities utilized two software healing with connection between graphs and function, giving the students the opportunity to plan, practice, and test by themselves. As a result, they understood the mathematical formulas and rules more deeply through their own trial and error, and then they gained thinking abilities necessary for doing mathematics. In addition, the activities boosted their confidence. 3. The understanding type of students was slightly different. Student A who received a high score, understood the most relationally, but student B who received a very high score, understood instrumentally and so couldn't app1y her knowledge to solving problems related to function concept. Student C who received a middle score lacked knowledge of mathematics but thought more creatively. The result is that students need an opportunity to think rotationally regardless of score. Therefore, this study concludes that using computer software will provide a positive effect for relational understanding in loaming function concept.

• The Journal of the Korea Contents Association
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• v.18 no.6
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• pp.50-62
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• 2018

This study is to ascertain the meaning of personal media as cultural intermediaries in the cultural diffusion, acceptance, and intermediation for the production and consumption of cultural contents. We examined the case of personal media, , which is one of popular YouTube channel in Korea and analyzed fifty most viewed videos in last two years based on four perspectives of digital cultural intermediaries: forms, expression methods, linguistic features, and evaluations. As expected, results demonstrate that shows characteristics of digital intermediary: diverse subjects without fixed rules, a variety of multimedia effects, colloquial style including neologism and multilingual, and users' high preferences caused by creator's sincerity. Our findings and limitations can serve directions of further empirical researches.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.3
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• pp.120-128
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• 2018

OLED Display fabrication system is one of the most complicated discrete processing systems in the world. As the glass size grows from $550{\times}650mm$ to $1,500{\times}1,850mm$ in recent years, the efficiency of Automated Material Handling System (AMHS) has become very important and OLED glass manufacturers are trying to improve the overall efficiency of AMHS. Aiming to meet the demand for high efficiency of transportation, various kind of approaches have been applied for improving dispatching rules and facility layout, while simultaneously considering the system parameters such as glass cassettes due date, waiting time, and stocker buffer status. However, these works did not suggest the operational policy and conditions of distribution systems, especially for handling unnecessary material flows such as detour. Based on this motivation, in this paper, we proposed an efficient algorithm for improving detour transportation in OLED FAB. Specifically, we considered an OLED FAB simplifying OLED production environment in a Korean company, where four stockers are constructed for the delivery of Lot in a bay and linked to processing equipments. We developed a simulation model using Automod and performed a numerical experiment using real operational data to test the performance of three operation policies under considerations. We showed that a competitive policy for assigning alternative stocker in case of detour was superior to the current dedicated policy using a specified stocker and other considered policies.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.219-224
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• 2017

These days, it is developed renewable energy-based wind power technology. Wind power generation is relatively quiet, and environmental damage is relatively low. In developed countries, a lot of wind power generation is being built. In Korea, the generation efficiency is low because there are few areas where the wind speed is maintained for four seasons. In recent years, forest damage, low noise, and environmental degradation complaints are frequent. In this paper, we performed an experiment to manage pitch control effectively by analyzing wind, direction, and temperature in real time based on FUZZY rule and cluster analysis.Using the new algorithm proposed by the simulation results, we could verify the efficiency of wind power generation pitch control for wind condition and direction condition by using the pitch control analysis technique.Furthermore, visualization representations have proven to automatically analyze early warning and efficiency of generator performance.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.55-62
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• 2018

American charter schools are independent public schools of choice, freed from rules but accountable for results. Charter schools have celebrated the 25th anniversary of its creation in 2017 and become part of landscape of public education in America. However, little research has been conducted on an individual charter school. This study aimed to examine the major factors of a successful charter school. A qualitative approach was employed. Seven one-hour in-depth interviews were conducted with semi-structured interview questions. And four teachers were participated. The conclusions are as follows: First, there is the combination of system and cultural factors as major successful factors of the Dayton Early College Academy. Second, system factors are the gateways and the advisory that is a twin at the charter school. The findings are considered to be applied for Korean educational settings and the implications can be used for policy development in Korea.