• Journal of Power Electronics
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• v.14 no.4
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• pp.778-787
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• 2014

This study presents an input filter resonance mitigation method for an AC-DC matrix converter. This method combines the advantages of the one-cycle control strategy and the active damping technique. Unnecessary sensors are removed, and system cost is reduced by employing the grid-side input currents as feedback to damp out LC resonance. A model that includes the proposed method and the input filter is established with consideration of the delay caused by the actual controller. A zero-pole map is employed to analyze model stability and to investigate virtual resistor parameter design principles. Based on a double closed-loop control scheme, the one-cycle control strategy does not require any complex modulation index control. Thus, this strategy can be more easily implemented than traditional space vector-based methods. Experimental results demonstrate the veracity of theoretical analysis and the feasibility of the proposed approach.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.32.1-32.1
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• 2008

It is well known that solar and space weather activities can influence the performance and reliability of modern technological system and can endanger human life. Since 2007, the Korea Astronomy and Space Science Institute (KASI) has initiated a research project for the construction of Korean Space Weather Prediction Center (K-SWPC) to make preparations for the next solar cycle maximum (~2012). In this talk, we briefly introduce the current progress of KASI activities for K-SWPC; extension of ground observation system, construction of space weather database and network, development of prediction models, and space weather effects. In addition, future plans for KSWPC will be discussed.

• Korean Institute of Interior Design Journal
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• no.21
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• pp.101-106
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• 1999

This study has been designed to explore the preferences of interior space for those living in apartment housing. It also examines the relationships between preferences of interior space, such as storage space, organization type of LDK(the living room, the dining room, and kitchen), space facing south, an interior garden, the concept of each room and the characteristics of the consumers, such as age, educational background employment status of homemakers, occupation of the primary income provider, family-life cycle, total household income, the size of floor space, and homeownership. In conclusion, this study suggests that at the time of designing apartment housing units, serious consideration should be given to the built-in closets or storage space in the anbang and to the location of a child's room facing to the south of the dwelling, especially for the families with a child attending primary school or younger and higher education level of homemaker. This study also recommends that the organization of the living room, the dining room, and the kitchen should be varied according to the housing size and the age of homemaker.

• Journal of Families and Better Life
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• v.26 no.6
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• pp.159-166
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• 2008

According to the change in diverse tendency of residents, construction companies has developed the brands of apartments with the concepts of LOHAS, well-being, ubiquitous, etc. The purpose of this study was to suggest space requirement and planning for residents characteristics. The questionnaire survey was adopted in this study and 252 cases were used for data analysis. The survey analysis has been made by using of SPSS WIN 12.0. The major findings were as follows; (1) Resident opinion about the direction of each space was investigated into the need of South-facing in master bedroom highly. (2) The residents didn't want to decrease the current size of each space, the space which wanted to increase was livingroom. (3) The significant variables of space requirement and planning for residents characteristics were family life cycle, the age of householder, the occupation of householder, the size of apartment.

• Journal of the Korean Society of Systems Engineering
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• v.12 no.2
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• pp.19-27
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• 2016

Many countries concentrated on the space developments to enhance the national security and the people's quality of life. A space launch vehicle for accessing the space is a typical large complex system that is composed of the high-technology like high-performance, high-reliability, superhigh-pressure, etc. The project developing large complex system like space launcher is mostly conducted in the uncertain environment. To achieve a goal of the project, its success probability should be enhanced consistently by reducing its uncertainty during the life cycle: it's possible to reduce the project's uncertainty by performing the risk management (RM) that is a method for identifying and tracing potential risk factors in order to eliminate the risks of the project. In this paper, we introduce the risk management (RM) process applied for a Space Launch Vehicle R&D Project.

• Bulletin of the Korean Mathematical Society
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• v.45 no.3
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• pp.419-425
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• 2008

For $q^5-q^3-q^2-q+1{\leq}d{\leq}q^5-q^3-q^2$, we prove the non-existence of a $[g_q(6,d),6,d]_q$ code and we give a $[g_q(6,d)+1,6,d]_q$ code by constructing appropriate 0-cycle in the projective space, where $g_q (k,d)={{\sum}^{k-1}_{i=0}}{\lceil}\frac{d}{q^i}{\rceil}$. Consequently, we have the minimum length $n_q(6,d)=g_q(6,d)+1\;for\;q^5-q^3-q^2-q+1{\leq}d{\leq}q^5-q^3-q^2\;and\;q{\geq}3$.

• International Journal of Aeronautical and Space Sciences
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• v.6 no.2
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• pp.17-22
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• 2005

As one of validation tool for attitude determination system, we have used various constraints using priori information which is known through base vector set up. However these conventional constraints cannot guarantee validity in terms of final solutions such as Euler angle. So we suggest attitude boundary concept to verify the final attitude solution on the flying airplane, it is based on the combination of velocity based attitude estimation technique and ambiguity resolution. we can say it can check invalid solution effectively at just one epoch without repeatability test of resolved cycle ambiguity. In this paper we show that the suggested constraint can effectively reject incorrectly resolved cycle ambiguity the conventional constraints have missed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.8
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• pp.725-734
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• 2011

At high angles of attack, aircraft dynamics can display an oscillatory lateral behavior that manifests itself as a limit cycle known as wing rock. In this paper, a classical and neural network based adaptive control design methods of adaptively stabilizing the oscillatory motion by adapting uncertainties are described in detail. All methods are simulated and compared using a model for an 80o swept delta wing.

• Journal of the Korean Geographical Society
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• v.39 no.6 s.105
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• pp.922-932
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• 2004

This paper uses the diary entitled Kieo, which was kept by Ryu Hyeong-eop for 38 years, to analyze the active space of small-scale Yangban landlords. Ryu lived during the period spanning from the end of the Taehan Empire through the colonial era. The researcher classified the contents of Kieo into different sections which were divided according to different stages of the writer's life, his objectives, destinations, and periods, and based on the writer's life-cycle, strived to recreate his spatial activities. As a result, researcher was able to ascertain that Ryu's spatial activities gradually increased, and that his active space also continuously expanded. Ryu's active space during his youth was narrow and centered around certain specific places. However, this active space gradually increased as time went by. It was during the middle stages of his life that the volume of his spatial activities was the heaviest. In addition, the objectives of his outings also became more diversified over time. This change was originated in the larger changes in his roles within the family and community, as well as by the changes in the periodic situation. Moreover, the regional sphere of Ryu's outings, including his day and over nights trips, allowed the researcher to form a better understanding of the daily living area of the Yangban.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.145-147
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• 2005

This paper presents a methodology for satisfying the thermal comfort of Indoor environment and reducing the summer peak demand power by minimizing the power consumption for an Air-conditioner within a space. KEPCO(Korea Electric Power Corporation) use the fixed duty cycle control method regardless of the indoor thermal environment. This method has disadvantages that energy saying depends on the set-point value of the Air-Conditioner and DLC has no net effects on Air-conditioners if the appliance has a lower operating cycle than the fixed duty cycle. A variable duty cycle estimates the PMV(Predict Mean Vote) at the next step with a predicted temperature and humidity coming from the back propagation neural network model. It is possible to reduce the energy consumption by maintaining the Air-conditioner's OFF state when the PMV lies in the thermal comfort range. The proposed methodology uses the historical real data of Sep. 7th, 2001 from a classroom in seoul to verify the effectiveness of the variable duty cycle method comparing with fixed duty cycle. The result shows that the variable duty cycle reduces the peak demand to 2.6times more than fixed duty cycle and increases the load control ratio by 8% more. Based on the variable duty cycle control algorithm, the effectiveness of DLC is much more improved as compared with the fixed duty cycle.