• Korean Journal of Plant Resources
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• v.26 no.4
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• pp.503-510
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• 2013

This study was conducted to determine the optimum intensity of root pruning and the initial seedling size of 1-year-old Quercus serrata for producing 2-year-old healthy seedlings. Large( > 26 cm hight) and small size ( < 24 cm hight) seedlings were pruned their root by the length of 5, 10, and 15cm and then transplanted on nursery. Stem height, root-collar diameter(RCD), height to RCD ratio(H/D ratio), shoot dry weight(DW) and root development were measured during first growing season after transplanting. Seedling size and pruning intensity influenced on shoot growth such as height, RCD, H/D ratio and DW after transplanting. In addition, the development of lateral roots such as number, length, DW and diameter were affected by the seedling size. Taproot pruned by 15cm was shown excellent above-ground growth in large seedling group, but pruned by 10 and 15cm showed respectively better shoot growth in small seedling group. Large seedlings increased their above-ground growth, taproot regrowth, and number of lateral roots more than those of the small seedlings. But the length and DW of lateral roots were increased in the small seedlings. In conclusion, in order to produce high quality 2-year-old seedlings, it is important to produce large size of Q. serrata seedlings. Also root pruning length of 1-year-old Q. serrata was reasonable on 15 cm in taller than 26 cm or 10cm in less than the height.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.672-678
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• 2017

In this paper, we studied a design method for a broadband quasi-Yagi antenna (QYA) for terrestrial digital television (DTV) reception. The proposed antenna is composed of a dipole driver, a rectangular patch type director close to the dipole, and a ground reflector printed on an FR4 substrate. A balun between a microstrip line and a coplanar strip (CPS) line is a rectangular patch inserted along the center of the CPS. The end of the balun is connected to the CPS line through a shorting pin. An antenna, as an design example for the proposed antenna, is designed for the operation in the frequency band of 470-806 MHz for terrestrial DTV, and the characteristics of the designed antenna are examined. The antenna has a good performance such as a frequency band of 430-842 MHz for a voltage standing wave ratio < 2, a gain > 3.7 dBi, and a front-to-back ratio > 7.4 dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.5
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• pp.906-912
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• 2017

In this paper, we studied a design method for a broadband 3-element quasi-Yagi antenna (QYA) for indoor digital television (DTV) reception. The proposed QYA employs a novel balun between a microstrip (MS) line and a coplanar strip (CPS) line feeding the driver dipole. The proposed balun is constructed by connecting the end of MS line to CPS line through a shorting pin, and the CPS and ground reflector are connected through a circular ring-type conductor. An antenna, as an design example for the proposed antenna, is designed for the operation in the frequency band of 470-806 MHz for terrestrial DTV. The antenna fabricated on an FR4 substrate with a size of $270mm{\times}150mm$ showed a good performance such as a frequency band of 470-820 MHz for a voltage standing wave ratio < 2, a gain > 4.0 dBi, and a front-to-back ratio > 8.4 dB over the DTV frequency band.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.79-88
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• 2019

This study analyzes the influential factors and patterns associated with death from aircraft accidents and incidents using data mining techniques. To this end, we used two datasets for aircraft accidents and incidents, one from the National Transportation Safety Board (NTSB) and the other from the Federal Aviation Administration (FAA). We developed our prediction models using the decision tree classifier to predict death from aircraft accidents or aircraft incidents and thereby derive the main cause factors and patterns that can cause death based on these prediction models. In the NTSB data, deaths occurred frequently when the aircraft was destroyed or people were performing dangerous missions or maneuver. In the FAA data, deaths were mainly caused by pilots who were less skilled or less qualified when their aircraft were partially destroyed. Several death-related patterns were also found for parachute jumping and aircraft ascending and descending phases. Using the derived patterns, we proposed helpful strategies to prevent death from the aircraft accidents or incidents.

• Korean Journal of Plant Resources
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• v.27 no.2
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• pp.174-182
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• 2014

This study was carried out to investigated the effects of soil type and light condition on seedling quality of rare and endemic plants Orostachys iwarenge and Orostachys iwarenge for. magnus. The best seedling quality of O. iwarenge and O. iwarenge for. magnus seedling were shown in Klasmann soil at non-shading or LED (Red+Blue) condition, 50% shading or LED (Red+Blue) condition, respectively. Survival of O. iwarenge seedling was not influenced by the period of experiment but survival of O. iwarenge for. magnus seedling in sandy soil conditions decreased significantly. Results of correlation analysis of seedling quality and survival rate, indicated that O. iwarenge showed a correlation of 0.8 or more at plant height, leaf length and fresh weight. O. iwarenge for. magnus showed a correlation of 0.8 or more at plant height, leaf width and leaf length. Especially, seedling survival of O. iwarenge and O. iwarenge for. magnus showed a correlation of 0.8 or more at first seedling survival and second seedling survival. It was important to manage the early seedling stages of O. iwarenge and O. iwarenge for. magnus. Therefore, seedlings with plant height (over 2.5~4 cm) and root length (over 3~5 cm) were grown vigorously at 35 days after the seedling was transplanted in mid-April in Klasmann soil of 72 plug cell tray at LED (Red+Blue) conditions.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.6
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• pp.417-427
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• 2010

In the ease that a new cross tunnel is constructed under the existing tunnel, development of a longitudinal arching would be influenced by the existing tunnel. But it is not enough to investigate. Especially, the influence of the structure loads on the ground surface on the new tunnel, which the under-passes existing tunnel has been rarely studied. This study, therefore, aimed to clarify the effect of the existing tunnel and the structure on the ground surface on the development of a longitudinal ground arching during the excavation of a cross tunnel under the existing tunnel. Two-dimensional model tests were carried out in the test box, whose dimension was 30 cm (wide) ${\times}$ 113 cm (deep) ${\times}$ 87 cm (high). The existing tunnel was made of S21 steel tube in 16 cm diameter and 1 mm thickness. The ground surface load was 4.9 kPa and was loaded on the model structure in the size with 30 cm width ${\times}$ 16 cm height. New tunnel was excavated in 250 mm height by a bench cut method. As results, the longitudinal arching would be developed but it was severely influenced by not only the existing upper tunnel but also the ground surface load. The influence of the ground surface load on the development of longitudinal ground arching around a new tunnel showed the highest value when the tunnel face located direct under the surface load.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.239-240
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• 2003

인간활동에 의해 오존이 감소하고 있다는 사실이 1985년 남극지역 전량오존에 관한 보고서로 처음 밝혀진 이후 계속적으로 북극지역과 중위도 지역에서도 동일한 현상이 일어나고 있다고 보고되고 있다(WMO/GAW No.143). 세계기상기구에서는 지상부근의 오존 또는 대기중의 오존전량에 대해서는 1950년대에 처음으로 전지구적차원의 오존관측이 실시되었으며, 1980년대초에 세계기상기구가 발족시킨 전지구오존관측시스템(Global Ozone Observing System, GO$_3$OS)에 의해 전세계적인 관측을 실시하고 있고 있다. (중략)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2774-2779
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• 2010

In this paper, we develope the bucket driven dredger for sludge treatment in box type culvert. The dreadger is opererated in $2m\;{\times}\;2m$ box type narrow culvert under the road, and controlled using remote controller on the remote zone. In order to operate under dangerous environment, we develope the bucket drived dredger, and we will commercialize the result.

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.134-137
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• 2007

GB-SAR (Ground-Based Synthetic Aperture Radar) 시스템은 지상에서 안테나의 정밀한 일축 제어를 통해 합성 구경(synthetic aperture) 효과를 얻어 높은 해상도의 영상을 얻는 레이더 스캐너(Radar Scanner) 의 일종이다. GB-SAR는 장기간에 걸쳐 안정 적으로 마이크로파 영상 및 위상을 얻을 수 있기 때문에，SAR간섭기법(interferometry)을 통하여 비교적 안정된 산란체의 시간에 따른 변위를 cm 혹은 mm 정밀도로 정량적으로 얻을 수 있으며, 또한 긴밀도(coherence)를 통해 산란체의 안정성을 정성적으로 추출해 낼 수 있다. 이 논문에서는 GB-SAR 시스템의 개발을 소개하고 여러 가지 영상 획득 모드를 통하여 얻어진 SAR 영상， DInSAR, Cross-Track InSAR, ${\triangle}k-InSAR$, PSInSAR, 및 SAR Polarimetry 등 GB-SAR 시스템의 다양한 응용 가능성을 간략하게 보였다.

• Defense and Technology
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• no.11 s.297
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• pp.44-55
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• 2003

최근의 국내.외에서는 정보의 보관 및 활용측면에서 CALS의 일환인 전자식 기술교범에 관한 개발이 활발하게 이루어지고 있다. 이미 국내에서도 K9 자주포에서 기술교범을 개발하여 운용중에 있으며, 해.공군에서도 전자식 기술교범을 개발 중 혹은 계획중에 있는 실정이다. 그러나 이러한 전자식 기술교범 구축을 위해 필요한 소프트웨어는 해외 도구를 활용중이거나 국내의 업체에서 개발된 표준화되지 않은 소프트웨어를 활용하고 있는 실정이다. 이에 따라 전자식 기술교범 개발비 상승, 상호 활용성 미확보, 기술교범 국방규격서 충족의 어려움 등 여러 가지 문제점을 내포하고 있다. 따라서 이러한 문제점을 해결하기 위해 국내의 육군 지상무기체계 전자식 기술교범 개발시 공통으로 적용이 가능한 표준 소프트웨어를 개발하게 되었다. 이 글에서는 이렇게 개발된 육군 전자식 기술교범 표준 소프트웨어(,KAIS : Korean Army IETM Software)에 대해 기술하고자 한다.