• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.92-94
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• 2013

최근 기상청에서는 대국민 지진조기경보 전달매체를 통하여 지진 관측 후 지진속보 혹은 지진통보 시간을 획기적으로 줄일 수 있는 '국가 지진 조기 경보 체계'를 2020년까지 구축하고자 하는 기본 계획을 수립하였으며, 본 계획의 일환으로 메시지 전달매체 중의 하나로 고려되고 있는 개인용, 이동형인 방송매체인 T-DMB 방송망과의 연계에 대한 연구가 진행되고 있다. 이에 본 논문은 지진 조기 경보 시스템과 지상파 DMB 방송망을 연계하여, 지진 재해와 같은 재난발생시 기존의 단순 속보형태로의 전달이 아니라, 수신기가 자동으로 재난방송 신호를 인지하여 사용자의 시청 유무와 상관없이 지진조기경보 정보를 제공할 수 있는 지진재해 자동인지 조기경보 서비스 기술 및 송수신 시스템을 소개한다.

• Journal of Nutrition and Health
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• v.40 no.8
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• pp.728-735
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• 2007

The present study was conducted to investigate the effect of iron-enriched cereal supplement and nutrition education program on nutritional status and life style of children. Elementary school students(n=170) aged of 11 years old at Seoul were participated. Subjects were supplemented with iron-enriched cereal for breakfast and provided with 2 sessions of nutrition education during 3 months. Intake of carbohydrate, iron, sodium, zinc, vitamin A, vitamin $B_1$, vitamin $B_2$, vitamin C, niacin, and folic acid was significantly increased after cereal supplement. Caloric intake was similar to KDRIs during both before and after cereal supplement. There was no improvement on exercise and dietary habits after nutrition education. Male students tended to sleep later, wake up early, and ate snack less than female. Cereal supplement was effective on improving nutritional status, but short-term nutrition education had no effect on modification of life style. Thus, further studies are required to develop long-term education program effective on improving lift style and eating habits in children.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.762-770
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• 2010

The researches about energy efficieny of wireless sensor MAC protocol is an issue in present days. Therefore, MAC and routing protocols for reducing energy consumption at sensor nodes is needed. In this study, a low-power MAC protocol for sensor network is proposed, which in based on X-MAC by exploiting virtual synchronization. The virtual synchronization technique lets senders postpone packet transmission until receivers' wake-up time, so that senders transmit only one or two short preambles. Using NS-2, a proposed MAC protocol improve the energy efficiency by 10% compared with the X-MAC protocol.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.388-393
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• 2001

An experimental study is conducted to investigate the interaction of vortices over a delta wing with leading edge extension(LEX) through the off-surface flow visualization and the 5-hole probe measurements of the wing wake region. Especially, the application of a new visualization technique is employed by ultrasonic humidifier water droplet and laser beam sheet. The results, both the off-surface visualization and the 5-hole probe, show that LEX tends to stabilize the vortices of the delta wing up to the high angle of attack even though the model is yawed. With increasing yaw, the windward leading edge vortex moves inward, and closer to the wing surface, while the leeward vortex moves outwards and away from the wing surface. The vortex interaction is promoted in the windward side, and is delayed in the leeward side.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4889-4902
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• 2018

It is a challenging issue to improve the energy efficiency of neighbor discovery in WSNs. This paper proposes an optimal discovery model (ODM) for the first time. Based on the model, we investigate the influence of the relative size of two unequal active slots on the energy efficiency. ODM provides the energy optimal value of the length of the larger active slot at a given duty cycle. Other than existing methods, the worst-case latency bound of ODM is only one period. This is a subversive conclusion, because almost all other related methods are based on a wake-up schedule that contains several periods. We theoretically deduce that ODM can reduce worst-case discovery latency by 43.89% compared to Searchlight-Trim when their duty cycles are the same. The simulations verify the advantage of ODM.

• Journal of The Korean Digital Architecture Interior Association
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• v.6 no.1
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• pp.25-32
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• 2006

This paper is a study on the anthroposophic characteristics shown in the first Goetheanum. Rudolf Steiner promoted anthroposophy base on the critique of modem times. His philosophy has developed in various areas such as medical science, agriculture, education, and art. In particular, his thinking was well expressed in the first Goetheanum which was built for Anthroposophical Society. The anthrososophic architectural theory is defined here as application of cosmology, metamorphology and geometry. Steiner defined geometry as a unconscious awareness inscribed in skeletal system of human body as humans have evolved in the process of cosmological development. As a result, Steiner's architecture was able to create metamorphological spaces with harmonizing geometric and organic factors. In respect of decoration, the shapes of plants applied to the decoration still kept individuality because of being made manually, thus perfect symmetrical architecture was impossible. Moreover, the first Goetheanum placed an emphasis on formative dynamics. This was to wake an individual's self-conscienceless up, by enabling him to experience with all the senses without reasoning from the precedent.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.247-248
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• 2015

Wind turbines causes instabilities on the grid as their penetration increase. To mitigate harmful effects from wind turbines, transmission system operator(TSO) set up some requirements to obligate for wind generation operator for grid connection. So wind farm management system(WFMS) has important role to follow requirement from TSO, WFMS calculates available real power by considering wake effects, and dispatches real power order to each wind turbine in wind farm to optimize for decreasing load fatigue. To verify operation of WFMS, real-time simulator(RTS) is necessary. This paper deals with RTS configuration to verify WFMS operation. RTS includes wind farm model and power flow code. Normally, wind farm equivalent simple model makes wind turbines in wind farm to one wind turbine mode which cannot verify power flow in wind farm and WFMS operation. Thus, this paper makes wind farm model using simple wind turbine model with transfer function. Matlab is used for make power flow code and wind farm model to impose RTS and those model is certified by PSCAD/EMTDC.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.142-144
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• 2012

T-DMB는 개인용, 휴대용, 이동형의 디지털방송매체로서의 특징을 가지고 있으며 최근들어 수신기 보급 증가로 새로운 재난방송 매체로 부상하고 있다. 그러나 현재의 T-DMB 기반 재난방송 기술은 T-DMB를 시청하고 있어야만 재난정보 수신이 가능하다는 한계를 갖고 있다. 이에 본 논문은 기존 T-DMB를 시청해야만 재난정보 수신이 가능한 기존 T-DMB 재난방송 서비스의 한계를 뛰어 넘어 재난발생시 수신기가 자동으로 재난방송신호를 인지하여 T-DMB를 시청하지 않더라도 재난정보를 제공하고 평상시 지역정보, 날씨 등 공공서비스 정보를 제공하는 T-DMB 재난방송 서비스 기술을 소개한다.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.1
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• pp.111-120
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• 2008

A particle image velocimetry (PIV) technique was employed to investigate the effects of blowing jet on the flow characteristics over stationary and pitch-oscillating airfoils. The Reynolds number was $7.84{\times}10^5$ based on the chord length. It was found that for stationary airfoil cases, continuous and pulsating blowing jets successfully reduced separated wake region at high angles of attack. A comparison study of two different types of jet blowing indicated that pulsating jet is more effective than continuous jet for flow separation control. Pulsating leading-edge blowing postpones flow separation and increased stall angle of attack by $2^{\circ}{\sim}3^{\circ}$. For pitch-oscillating airfoil cases, the PIV results showed that blowing jet efficiently delays the separation onset point during pitch-up stroke, whereas it does not prevent flow separation during pitch-down stroke, even at angles of attack smaller than static ones.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.2
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• pp.171-183
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• 2013

We examined breakfast patterns and preferences in 420 elementary school students (216 boys, 206 girls) in the Chung-nam area. About thirty percent of the subjects had breakfast irregularly. The main reasons for skipping breakfast were having a 'poor appetite' and being 'busy'. The person who prepared breakfast was the 'mother' in both groups. Subjects were satisfied with 'Korean style' menu but dissatisfied with 'rice porridge-style'. Multiple regression analysis indicated that the 'frequency of having breakfast' was positively related to the subject's 'frequency of having breakfast with their mother'. On the other hand, the frequency of having breakfast was negatively related to feeling obligated to have breakfast. The multiple regression analysis also indicated that a Korean style 'breakfast preference' was positively related to the mother's age and negatively related to their 'wake-up time'. A 'breakfast preference for bread and milk' was positively related to 'bed time' and negatively related to the 'age of the father'. Our results will provide critical information for the nutritional education of elementary school students.