• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.4
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• pp.349-360
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• 2006

Controller for doubly-fed induction-type wind generation system should be designed with mechanical power on blade. The controller in this paper consists of upper level controller and lower level controller. The upper level controller determines operating modes according to mechanical input power and calculates proper reference values. There are 4 operating modes - minimum speed control, variable torque control, torque limit control and idle mode. The lower level controller performs current regulated PWM control of rotor-side converter and grid-side inverter. A wind turbine simulator is implemented using doubly-fed induction-type generator and DSP based back-to-back converter to verify the performance of designed controller experimentally.

• Review of KIISC
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• v.27 no.2
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• pp.34-40
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• 2017

제어시스템(발전시설, 전력시설, 교통시설 등)은 생산성, 가용성, 안전성을 목적으로 다양한 제어기기들로 구성되며, 물리적으로 다양한 위치에 분산되어 운영되고 있다. 그리고 안전성과 가용성을 유지하기 위해 시스템 도입 시 기존 시스템에 영향을 미치지 않는지 검증을 수행 후 시스템을 도입한다. 이러한 이유로 신규 기술의 도입이나, 기기의 변경이 자유롭지 않다. 이와 같은 제어시스템의 특성으로 인해 현재 증가되고 있는 제어시스템 사이버공격에 대한 보안대책 또는 기술들의 적용이 쉽지 않아 사이버공격에 취약한 상황이다. 제어시스템은 상위 시스템의 제어 명령을 통해 하위 제어기기 또는 필드기기를 제어하는 형태로 제어 명령의 무결성 유지가 특히 중요하다. 이는 곧 제어시스템에 환경에 접근한 공격자가 인가되지 않은 장비를 제어시스템에 연결하고, 악성 제어명령을 전송하게 된다면 제어기기는 이를 인지하지 못하고 정지되거나 오작동을 유발 할 수 있다는 것을 의미한다. 본 논문에서는 제어시스템 내 제어명령의 무결성 유지를 위해 임베디드 Add-on 단말을 통해 OTP 값을 생성, 전달, 검증하는 방안을 제안한다. 해당 방안은 상위노드와 하위노드 사이에 Add-on 장치를 두어 상위노드에서 제어명령 발생 시, 제어명령에 OTP값을 통해 캡슐화하고 하위노드로 전달한다. Add-on 장비는 일반 IT시스템과 상이한 제어시스템의 특성에 맞게 고안되었으며 제어시스템 내에 발생되는 제어명령 위변조, 제어명령 재사용 공격 등을 차단 할 수 있다.

• Korean Journal of Culture and Social Issue
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• v.21 no.3
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• pp.355-376
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• 2015

This study purposed to reveal the process of change in dismissed workers' experiences at dismissal and the subsequent period of unemployment. For this purpose, six dismissed workers' psychological experiences were explored using the phenomenological method as one of qualitative research methods. Data were collected through in-depth interviews with the workers on their psychological experiences at dismissal, continuous psychological or physical changes after dismissal, current state, etc. and from the analysis of the data were derived 12 sub-themes and they were categorized into four main themes. The four main themes were 'emotions experienced with dismissal,' 'psychological and physical symptoms,' 'patterns of social perception,' 'and ways of coping with dismissal.' The main themes and their sub-categories were described, and dismissed workers' specific experiences related to them were explained. Lastly, dismissed workers' changes and experiences were discussed based on previous studies.

• 한국노년학
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• v.31 no.4
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• pp.855-870
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• 2011

This paper investigates the effect of retirement-related subjective expectations on the capital accumulation of the Korean baby-boom generation. Using the 1st, 2nd waves of the KLoSA (2006, 2008), we estimate the distributional effects with quantile regression. In addition, the endogeneity of the expectation variables is handled using the fixed effect model. The quantile regression results reveal that the schooling, gender and the number of children are important determinants, but their effects are heterogenous across quantiles to a significant margin. The expectations of the stronger bequest motives and longer lifespan turned out to lead to more capital accumulation. The expectation regarding the expanded role of government retirement support seemed to crowd out private savings for the baby boomers with the total assets over 0.7 percentile.

• 한국벤처창업학회:학술대회논문집
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• 2022.04a
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• pp.89-97
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• 2022

본 연구에서는 창업 성장단계별 특허분석 요인들의 중요도와 우선순위를 제시하였고, 구체적으로 창업준비기, 창업기, 성장기, 성숙기 창업 성장단계 기준으로 구분하여 가장 먼저 선행되어야 할 특허분석 요인을 AHP기법을 활용하여 분석하였다. 분석결과, 상위요인의 중요도는 창업준비기(.633), 창업기(.231), 성장기/성숙기(0.136) 순으로 나타났다. 상위요인인 창업준비기의 하위요인 중요도는 환경분석(.593), 특허조사(.236), 특허분석(.171) 순으로 분석되었다. 창업기의 하위요인 중요도는 사업화전략(.415), R&D전략(.333), 보완출원전략(.138), 보유특허분석(.114) 순이고, 성장기/성숙기 하위요인 중요도는 후속IP창출(.337), 핵심특허 대응전략(.260), 후속R&D방향제시(.183), 특허인프라구축(.137), 라이센싱(매입)전략(.083) 순으로 나타났다. 전체 복합신뢰도 상위권 중요도 순위로는 1위 환경분석, 2위 특허조사, 3위 특허분석, 4위 사업화전략, 5위 R&D전략, 6위 후속 IP창출 순으로 나타났다. 이러한 연구 결과를 통해 창업을 준비하는 창업자에게 특허와 관련하여 단계별 집중해야 하는 요인의 중요도와 우선순위를 제시하고 더 생산적이고 효율적인 일들에 집중할 수 있는 가이드가 되기를 바란다.

• Journal of the Korean Society of Radiology
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• v.6 no.3
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• pp.173-182
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• 2012

It was well known that working memory highly related with academic achievement. The aim of this study was to investigate the differences of brain activation which visually evoked working memory(encoding and retrieval) through functional Magnetic Resonance Imaging(fMRI) in Higher Academic Achievement Group(HAAG) and Lower Academic Achievement Group(LAAG) of college students. 20 assigned college students participated in fMRI studies. They underwent totally 210 seconds repeated paradigm. Stimulation paradigm composed with resting time and encoding and retrieval seeing the figures from the mirror with head coil. The brain activation maps and their quantification were analyzed by the statistical parametric mapping(SPM99) program from level of significance 95%. HAAG was more significantly higher than LAAG in bilateral prefrontal lobe(brodmann 46) associated with working memory, inferior parietal lobe associated with attention, and visual association area in encoding figures test. Right dosoprefrontal lobe(BA 44), right fusiform gyrus associated with decision of figure and, lingual gyrus were more activated in retrieval test with HAAG. On the other hand, LAAG was more significantly higher than HAAG in cingulate gyrus during encoding test. Thalamus, basal ganglia, cerebellum were more activated in retrieval test. Consequently, We could guess from these results HAAG more effectively executed than LAAG in visual working memory test.

• Korean Journal of Child Education & Care
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• v.18 no.3
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• pp.91-104
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• 2018

Objective: The purpose of the study was to explore early childhood teachers' content knowledge and knowledge level on unification education through an analysis of a concept map (Novak & Gowin, 1984). Methods: The subjects, including 65 early childhood teachers in a metropolitan area, were asked to draw concept maps illustrating their understanding of unification education for young children. The collected concept maps were analyzed using the methods utilized by Novak and Gowin (1984) as well as You and Kim (2018). Results: In terms of early childhood teachers' content knowledge, 282 superordinate concepts and 1,766 subordinate concepts were shown. The 282 superordinate concepts were categorized into 7 representative superordinate concepts: understanding of North Korean, understanding of separation/unification, identification as Korean citizen, unification policy, relationship between South Korea & North Korea, educational activities, connection with home and society. In terms of early childhood teachers' knowledge level, the numbers of subordinate concepts and hierarchical level were shown to be varied according to the 7 representative superordinate concepts. Conclusion/Implications: Discussions were included to support and enhance early childhood teachers' content knowledge on unification education for young children through the development of comprehensive programs and teacher education.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.1
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• pp.42-56
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• 2002

It is possible but not efficient to model and simulate asynchronous microprocessors with the existing HDLs(HARDware Description Languages) such as VHDL or Verilog. The reason it that the description becomes too complex. and also the simulation time becomes too long to explore the design space. Therefore it is necessary to establish a methodology and develop a tool for modeling the handshake protocol of asynchronous microprocessors very easily and simulating it very fast. Under this objective an efficient CAD(Computer Aided Design) tool SLEDS(System Level Event-Driven Simulator) was developed which can evaluate performance of a processor through modeling with a simple description an simulating with event driven engine in the system level. The ultimate goal in the tool SLEDS is to fin the optimal conditions for a system to produce high performance by balancing the delay of each module in the system. Besides SLEDS aims at verifying the design through comparing the expected results with the actual ones by performing the defined behavior.

• The Korean Society of Law and Medicine
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• v.16 no.1
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• pp.125-151
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• 2015

South Korea's medical system has dual systems-that is, Oriental and Western Medicine. Both are different from method for diagnosis or treatment of diseases and Scientific principle. Of the characteristics of Oriental medical practice in comparison with Western medical practice, notably, it is difficult to acknowledge specific constitutions, Oriental medical doctors' discretion is broad, and Oriental medical practice has a low invasiveness. Thus, it is difficult to acknowledge human specific constitutions when grounded on Oriental medical principles, thereby making it difficult for Oriental medical doctors to argue such specific constitutions as a means of defending against their medical negligence. And, it is difficult to prove Oriental medical doctors' negligence because Oriental medical doctors' scope of discretion is broad. Collaboration of Oriental medicine and western medicine can diagnose and treat the patient's diseases from a different viewpoint, making both medicines complementary. Oriental medicine and western medicine are independent of each other, equal, thus making them divided horizontally. Horizontal medical service division involves the principle of trust, but the principle of trust does not always apply to Oriental medicine and western medicine, because if patients shift from one area of medicine to another, the scientific principle, diagnostic method and treatment method of that medical area should be different. Application of the principle of trust to both of them needs to be analyzed according to types of medical institutions where transfers occur, and to the scope of work division between them.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.99-106
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• 2004

This paper presents some comparisons between Cournot-Nash and Stackelberg game in bi-level program, composed of both upper level program and lower level one. The upper level can be formulated to optimize a specific objective function, while the lower formulated to express travelers' behavior patterns corresponding to the design parameter of upper level problem. This kind of hi-level program is to determine a design parameter, which leads the road network to an optimal state. Bi-level program includes traffic signal control, traffic information provision, congestion charge and new transportation mode introduction as well as road expansion. From the view point of game theory, many existing algorithms for bi-level program such as IOA (Iterative Optimization Assignment) or IEA (Iterative Estimation Assignment) belong to Cournot-Nash game. But sensitivity-based algorithms belongs to Stackelberg one because they consider the reaction of the lower level program. These two game models would be compared by using an example network and show some results that there is no superiority between the models in deterministic case, but in stochastic case Stackelberg approach is better than that of Cournot-Nash one as we expect.