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Seongnam, South Korea

Nguyen H.C.,Yonsei University | Jung J.,Yonsei University | Kim D.,Yonsei University | Heo J.,Yonsei University | Kim K.,KFRI
33rd Asian Conference on Remote Sensing 2012, ACRS 2012 | Year: 2012

To achieve quantitative information of aboveground forest biomass carbon stock by remote sensing approach, a number of methods have been conducted. This study is to examine application of regression tree (tree decision) and k-Nearest Neighbor (kNN) algorithm for forest carbon stock estimation of Chungnam province in South Korea. Dataset used for this research includes Landsat Thematic Mapper (TM) images and field data from 5th National Forest Inventory (NFI). As a result, total above forest carbon stock estimated by kNN (20,467,652.900 ton C) model is closer to the number given by Korean Institutes of Forest than regression tree's number (20,239,247.239 ton C), however RMSE from latter algorithm is less than the former, 19.168 ton C/ha and 20.063 ton C/ha, respectively. Source


Kim J.Y.,Hoseo University | Lee J.Y.,Hoseo University | Lee W.Y.,KFRI | Yi Y.,Hoseo University | Lim Y.,Konkuk University
Korean Journal of Microbiology and Biotechnology | Year: 2010

Plants extracts are good resources to find functional compounds for human health. The following eight plants were collected and total phenolic contents were determined. Acerpsedo-siebolianum showed the highest phenolic contents, 16.4 mg/g, whereas Cercidiphyllum japonica showed the lowest contents, 1.9 mg/g. The DPPH free radical scavenging capacities of the plant extracts showed high activity in following order : Acer ginnala (21.3 μg/mL) > Cornus walteri (23.9 μg/mL) > Distylum racemosum (29.2 μg/mL) > Castanopsis cuspidata var. Thunbergii (31.7 μg/mL) > Acer psedo-siebolianum (34.6 μg/mL) > Thuijopsis dolabrata cv. Aurea (53.1 μg/mL) > Cercidiphyllum Japonica (115.2 μg/mL). Also the mushroom tyrosinase inhibitory activities of total extracts were determined at different concentration. D. racemosum extract showed highest (49.1% at 1,000 mg) in inhibitory activity than other seven extracts. The ethanol fraction (IC 50 value: 118.1 μg/mL) from D. racemosum showed more inhibitory activity than ethyl acetate fraction (IC50 value: 203 μg/mL). The ethanol fraction on showed no significant cytotoxicity in B16/F1 cells line up to 60 μg/mL. Over 80 μg/mL of ethanol fraction showed cytotoxicity in B16/F1 cells. The melanin contents of cells were significantly attenuated by ethanol fraction in a dose-dependent manner. The IC50 value of ethanol fraction was 75.4 μg/mL. Source


Liu P.,Washington State University | Upadhyaya P.,Xilinx Inc. | Jung J.,Washington State University | Heo D.,Washington State University | And 2 more authors.
Electronics Letters | Year: 2012

A novel LC VCO topology with switched current source is presented. Theoretical analysis is given to show the reduction of cross-paired transistors' drain current duty cycle with the implementation of current source switching, which reduces the upconversion of 1/f noise and also provides noise shaping by directly reducing 1/f noise. A 5.25-5.5 GHz LC VCO has been fabricated and measured for the proposed topology, achieving a FOM of -191 dBc/Hz, which is among the best published FOM results for 5-6 GHz VCOs in standard CMOS process. © 2012 The Institution of Engineering and Technology. Source


Liu P.,Washington State University | Upadhyaya P.,Xilinx Inc. | Jung J.,Washington State University | Heo D.,Washington State University | And 2 more authors.
Electronics Letters | Year: 2011

A novel load-independent switched LC VCO with PMOS dynamically switched current source and harmonic filtering is presented. The VCO has been designed and implemented with Jazz 0.18m CMOS process. At 5.47GHz carrier frequency, the VCO achieves a measured phase noise of -122.4 and -102dBc/Hz at 1MHz and 100kHz offset, respectively. The VCO works between 5.3-5.7GHz, which yields a tuning range of 400MHz. This VCO consumes 4.2mA from a 1.2V supply and the figure-of-merit (FOM) is -190.2dBc/Hz, which is among the best published FOM results for 5-6GHz VCOs in standard CMOS process. © 2011 The Institution of Engineering and Technology. Source


Lee S.H.,KFRI | Lee S.,KFRI | Kim J.,Hoseo University | Lee C.-K.,Korea University | And 2 more authors.
Korean Journal of Microbiology and Biotechnology | Year: 2012

Five strains out of 200 candidate strains (SG 1-9, 1-12, SG 2-8, 2-10, and 2-17) were selected to determine their antifungal activity against Raffaelea quercus-mongolicae. The 16S rDNA sequences of the five strains were determined by sequencing analysis and analyzed by the homology of the blast program at NCBI. The homology search showed that SG 1-9 and 1-12 had a 98% homology with Streptomyces cinnamoneus and 98% homology with Burkholderia cepacia, while SG 2-8, 2-10, and 2-17 had a 99% homology with Streptomyces fradiae, a 97% homology with Staphylococcus epidermidis, and a 99% homology with Staphylococcus epidermidis. Out of the five selected strains, organic extract and protein extracts of SG2-17 strain broth were employed to determine antifungal activity against Raffaelea quercus-mongolicae. The organic extract exhibited antifungal activity, but the protein extracts did not demonstrate such an activity. Three organic solvents, butanol, benzene, and ethyl acetate, were also used for determination of antifungal activities. The activity measurements revealed that benzene extract possessed the greatest inhibitory effect on the growth of Raffaelea quercus-mongolicae, with the next highest being butanol extract, and ethyl acetate extract being the lowest. Source

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