• Microbiology and Biotechnology Letters
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• v.35 no.1
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• pp.1-10
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• 2007

The 44 endophytic bacterial strains were isolated from surface-sterilized root of rice cultivated in seven different locations of Chungcheong province, Korea. Each isolate was introduced into rice seedlings grown gnotobiotically by inoculating scissor-cut first true leaf with cell suspensions, and the colonization capacity of each isolate in root tissue was analyzed at 7 days after inoculation. Sixteen out of 44 isolates were re-isolated from root successfully with the frequency of $10^{3-5}$ CFU/g tissue. Interestingly, seven out of 16 isolates were identified as Burkholderia species. The identity between inoculated strains and re-isolates was confirmed by genomic finger-printing and 16S rDNA sequence analysis. By a confocal laser scanning microscopic observation it was revealed that KJ001 strain, one of the sixteen isolates tagged with gfp colonized in root tissue especially around xylem. Six out of seven Burkholderia strains obtained in this study showed antagonizing activities against seven different fungal pathogens, contain nifH gene, and five of them enhanced growth of cucumber over 30%. The isolates showed no hypersensitive response on tobacco leaves and no pathogenecity in rice. From these results it was found that the endophytic Burkholderia strains will be useful in agriculture to develop a biocontrol agent or a bio-fertilizer.

• Strategy21
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• s.42
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• pp.114-153
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• 2017

고도화 및 가시화되고 있는 북한의 '잠수함발사탄도미사일(SLBM: Submarine Launched Ballistic Missile)'위협에 대응하기 위한 효과적인 전략수단으로써 핵추진잠수함의 필요성에 대한 국민적 관심이 고조되고 있다. 핵추진잠수함의 전략적 가치에 대한 논의가 활발히 진행되고 있는 가운데, 주변국과의 갈등과 국제사회의 비핵화 규범의 미 준수 논란 등 핵추진잠수함 확보과정에서 야기될 수 있는 대·내외의 정치·외교적 파장에 대한 우려의 목소리 또한 높아지고 있다. 그러나, 핵추진잠수함의 필요성 및 확보와 관련한 지금까지의 대부분의 논의들은 한국의 '내부적 논의(Just our own scenario)'에 그치는 한계를 보이고 있다. 전략무기체계로써의 상징성과 그에 따르는 대외적 민감성을 고려 시 일방적이고 독자적인 핵추진잠수함 확보노력은 과정상의 시행착오와 불확실성을 더욱 가중시켜 정책적 실패로 귀결될 수 있는 위험성을 내포하고 있다. 특히, 한반도 평화와 아태지역의 안전보장이라는 공동의 전략적 목표를 공유하고 있는 동맹국인 미국의 공감대와 지지가 뒷받침되지 않은 독자적인 핵추진잠수함 확보노력은 큰 난항이 예상되며 자칫 서로간의 '전략적 신뢰(Strategic Trust)'를 무너뜨려 '한미동맹의 결속력(Alliance Cohesion)'을 약화시키는 요인으로 작용할 수 있다. 미국의 동의와 지지에 기반한 핵추진잠수함 확보를 위해서는 한국의 핵추진잠수함 확보가 동맹의 전략목표 및 미국의 전략적 이해관계에 미칠 수 있는 긍정적, 부정적 효과에 대한 충분한 검토와 논의가 선행되어야 한다. 한미동맹의 공동의 전략목표와 미국의 전략적 이익에 상충하는 한국의 핵추진잠수함 확보시도는 성공 가능성이 낮기 때문이다. 본 연구에서는 현실화되고 있는 북한의 핵위협에 대응하고 지역안전보장에 기여할 수 있는 미국과의 연합방위력 증강차원에서의 한국의 핵추진잠수함의 전략적 효용성을 분석하였다. 더불어, 한국의 핵추진잠수함 확보과정에서 야기될 수 있는 대·내외의 기술적, 정치·외교적 사안들을 살펴본 후 한미동맹 차원에서의 정책적 해결방안을 제시하였다. 연구목적을 위해 유사한 역사적 사례연구를 통해 교훈을 도출하였으며, 미국 오바마 1기 행정부에서 미국의 아태지역 및 대북정책을 주도한 전 미국 국무부부장관 제임스 스타인버그(James Steinberg) 및 여러 미국 내 한반도 전문가들의 의견을 수렴하였다. 본 연구가 한국의 핵잠수함 확보를 위한 한미간 발전적 논의의 시발점이 되기를 기대한다.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.103-107
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• 2005

In order to investigate the velocity structure of the southern part of the Korean peninsula, exploded seismic signals were recorded for 120 s along a 294-km WNW-ESE line and 150 s along a 335-km NNW-SSE line in 2002 and 2004, respectively. Velocity tomograms were derived from inverting first arrival times. One-dimensional velocity models derived by joint analyses of teleseismic receiver functions and surface wave dispersion at several stations near the profiles were uesd to build initial models. The raypaths indicate several midcrust interfaces including ones at approximate depths of 2.0 and 14.9 km with refraction velocities of approximately 6.0 and 7.1 km/s, respectively. The deepest significant interface varies in depth from 30.8 km to 36.1 km. The critically refracting velocity varies from 7.8 to 8.1 km/s along this interface which may correspond to the Moho discontinuity. The velocity tomograms show (1) existence of a low-velocity zone centered at 6-7 km depth under the Okchon fold belt, (2) extension of the Yeongdon fault down to greater than 10 km, and (3) existence of high-velocity materials under the Gyeongsan basin whose thickness is less than 4.2 km.

• Journal of the Korean earth science society
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• v.32 no.6
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• pp.602-612
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• 2011

Jeju Island, a volcanic island located in South Korea, has been one of the main targets of geophysical and/or geological studies because of its tectonic importance related to the volcanism and tectonic link to the southern part of the Korean Peninsula. Recently, as a number of broad-band magnetotelluric (MT) measurements were made, we have examined the deep part of the island. In such an insular setting, it is not easy to properly recover the deep structures such as the lower crust and the upper crust using MT data, because their low-frequency components are strongly affected by the surrounding sea of the island. In this study, we apply the sea-effect correction to the existing MT data collected at a total of 102 sites in Jeju Island. The sea-effect correction makes remarkable changes in the observed MT data at frequencies below 1 Hz, clearly indicating the existence of a conductive lower crust. The 2-D inversion results for both Jeju Southern Line (JSL) and Jeju Northern Line (JNL) show that the transition zone separating the resistive upper crust and conductive lower crust exists at a depth of 20 km on average.

• Journal of the Korean earth science society
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• v.34 no.7
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• pp.669-680
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• 2013

Ozone sensitivity analysis with respect to $NO_x$ is conducted around the south-eastern area of the Korean Peninsula. WRF-CMAQ modeling system is used to simulate a local circulation and high ozone episode day. To analyze the sensitivity, the adjoint model for CMAQ is adopted in this study. The purpose of current study is to investigate the location that affects a day time ozone concentration of these receptors on the high ozone episode day. Adjoint sensitivity analysis for Daegu shows two areas of influence. One is the range from the neighboring location to Pohang and it affects mainly on the same day as receptor time. The other is the remote south-eastern area from Daegu. This remote influence area suggests that $NO_x$ emitted on the previous day can change the ozone concentration at receptor time. The influence area for Busan, on the other hand, is originated only from the emission on the previous day because the sea-breeze occurred on the episode day makes low influence of surrounding emission. The cross sectional analysis reveals that $NO_x$ advection is important not only near the surface of land but also around the height of boundary layer.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.4
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• pp.51-61
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• 2012

Kyong-Eui Railway used to be one of the major cross-country railways connecting Busan and Shineuiju. Being the central axis of logistics and transportation in Korea, it also signifies a symbolic meaning of the people's desire for the unification of divided Korean peninsula. A steam locomotive that had stopped in Jangdan Station was bombed out during the Korean War. The locomotive has been neglected and covered with rust in DMZ over a half century, and now is becoming a historic reminder of divided Korea. The initial design approach was based on the three main perspectives of the relocation plan of the steam locomotive in Jangdan Station which is designated as the registered cultural asset no. 78: historical significance, role of a monumental space, and influence on and from the local culture and tourism. Three design subjects were especially highlighted which would represent the identity of the cultural asset, the stream locomotive. First, a vertical watching deck was installed to provide various view points toward the locomotive while ensuring the security of visitors as well as the cultural asset. Second, the Dokgae bride area has good design potentials being on the railway. However, the site is too narrow. Thus, a new ramp and a stairway were placed responding to the existing topography so that the pedestrian environment could be secured last, to respect the local context where the locomotive was originally located, mulberry trees in the locomotive were transplanted as well. Flowering plants were planted around the display area for better ventilation to minimize the negative impact on the locomotive.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.508-520
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• 2016

In this study, variations in water temperature after the passage of typhoons in Korean waters from 2009-2015 were analyzed. Sea surface temperature (SST) images derived from satellite remote sensing data were used, and water temperature information came from real-time mooring buoys at Yangyang, Gangneung, Samcheok and Yeoungdeok, while wind data was supplied by the Korea Meteorological Administration. Differences in SST observed before and after the passage of a typhoon using the SST images were found to be affected by wind direction as well as hot and cool seasonal tendencies. Coastal water temperatures of the eastern part of the Korean peninsula, located to the right of a typhoon, as in the case of typhoons Muifa, Chanhom, Nakri and Tembin, were lowered by a coastal upwelling system from southerly winds across the water's surface at depths of 15m and 25m. In particular, typhoons Chanhom and Tembin decreased water temperatures by about $8-11^{\circ}C$ and $16^{\circ}C$, respectively. However, temperatures to the left of the typhoons were increased by a downwelling of offshore seawater with a high temperature through the mid and lower seawater layers. After the passage of the typhoons, further mixing of seawater at a higher or lower temperature due to southerly or northerly winds, according to the context, lasted for 1-2 or 4 days, respectively.

• The Journal of the Petrological Society of Korea
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• v.20 no.4
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• pp.191-206
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• 2011

The emplacement ages, whole-rock geochemistry and Sr-Nd isotopic compositions of granitoid rocks from Cheongju area, South Korea, were investigated for delineating their petrogenetic link to the Jurassic Daebo granitoid rocks. Zircon crystals were collected from the diorite, biotite granite and acidic dyke samples in a single outcrop. Cross-cutting relationships show that the emplacement of diorite was postdated by the intrusion of biotite granite. Both rocks have been subsequently intruded by acidic dyke. The U-Pb isotopic compositions of zircon from the diorite, biotite granite, and acidic dyke were measured using a SHRIMP-II ion microprobe, yielding the crystallization ages of $174{\pm}2Ma$, $170{\pm}2Ma$, and $170{\pm}5Ma$, respectively, with 95% confidence limits ($t{\sigma}$). The emplacement ages are consistent with those determined from the above relative ages. The major and trace element patterns of the rocks are consistent with those of the Jurassic Daebo granitoid rocks, possibly suggesting a subduction-related I-type granite. The geochemical signature is, however, betrayed by the Sr and Nd isotopic compositions of these rocks. The isotopic signatures suggest that the rocks were produced either by the partial melting of lower-crust or by the mantle-derived magma contaminated by the basement rocks during its ascent and/or emplacement. In addition, the inherited ages of zircons of the rocks (ca. 2.1, 1.8, 0.8 and 0.4 Ga) suggest a possible assimilation with crustal rocks from the Gyeonggi massif and Ogcheon metamorphic belt.

• Journal of the Korean association of regional geographers
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• v.5 no.1
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• pp.151-162
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• 1999

This study is a comparative analysis of sea level and 500hPa surfaces between dry year and wet year, which are selected by variability of precipitation and standardized anomalies in Korea in early autumn. While the amount of precipitation of early autumn decreases, the variability of precipitation increases rapidly reflecting the strength and weakness of Kaul Changma front and the occurrences of the typhoonic precipitation. The regional distribution of the variability of precipitation shows west-high, east-low pattern in which the east coast and the southeastern coast shows low, but high in the southwestern coast. In the anomalies distribution of sea-level and 500hPa surfaces, during dry year, the northern part of Siberia and the core area of North Pacific high shows negative anomalies, on the contrary, there were positive anomalies in wet year at the same areas. In addition, at the 500hPa level, while the Korean peninsula was located at the west of deep trough with low zonal index in dry year, the peninsula was influenced by weak trough with high zonal index showing strong zonal flow in wet year. During dry year the height of 500hPa surface is low at the north of $40^{\circ}N$, but high in wet year. In consequences, this study identified that the occurrences of dry year and wet year were influenced by the seasonal variations of the strength and the weakness of North Pacific high and Siberian high.

• Journal of Korea Water Resources Association
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• v.50 no.2
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• pp.75-87
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• 2017

In recent decades, extreme events have been significantly increased over the Korean Peninsula due to climate variability and climate change. The potential changes in hydrologic cycle associated with the extreme events increase uncertainty in water resources planning and designing. For these reasons, a reliable changing point analysis is generally required to better understand regime changes in hydrologic time series at watershed scale. In this study, a hierarchical changing point analysis approach that can apply in a watershed scale is developed by combining the existing changing point analysis method and hierarchical Bayesian method. The proposed model was applied to the selected stations that have annual rainfall data longer than 40 years. The results showed that the proposed model can quantitatively detect the shift in precipitation in the middle of 1990s and identify the increase in annual precipitation compared to the several decades prior to the 1990s. Finally, we explored the changes in precipitation and sea level pressure in the context of large-scale climate anomalies using reanalysis data, for a given change point. It was concluded that the identified large-scale patterns were substantially different from each other.