• Progress in Superconductivity and Cryogenics
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• v.8 no.2
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• pp.17-19
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• 2006

A novel clock distribution technique for pipelined-RSFQ logics using variable Bias Currents of JTLs as delay-medium is newly proposed. RSFQ logics consist of several logic gates or blocks connected in a pipeline structure. And each block has variable delay difference. In the structure, this clock distribution method generates a set of clock signals for each logic blocks with suitable corresponding delays. These delays, in the order of few to tens of pS, can be adjusted through controlling bias current of JTL of delay medium. While delays with resistor value and JJ size are fixed at fabrication stage, delay through bias current can be controlled externally, and thus, is heavily investigated for its range as well as correct operation within current margin. Possible ways of a standard delay library with modular structure are sought for further modularizing Pipelined-RSFQ applications. Simulations and verifications are done through WRSpice with Hypres 3-um process parameters.

• Asian Journal of Innovation and Policy
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• v.12 no.3
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• pp.277-303
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• 2023

The importance of ecosystem service such as green spaces has risen due to restrictions on outdoor activities amid the climate crisis and COVID-19. While gardens significantly impact economic development, quality of life, and social well-being, comprehensive studies on their multidimensional values are lacking. This research categorizes garden values into social, cultural, environmental, and health dimensions and proposes an integrated assessment framework that introduces detailed elements and evaluation methods. An empirical assessment of carbon storage index in two Korean gardens, Semiwon and Juknokwon, reveals Semiwon's higher carbon storage per unit area. The proposed framework, emphasizing a quantitative approach, enables cross-national and regional comparisons, contributing to a broader understanding and evaluation of garden values beyond specific facilities.

• Journal of Adhesion and Interface
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• v.8 no.1
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• pp.1-7
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• 2007

The objectives of this study are to analyze emitted components and concentrations of VOCs (Volatile Organic Compounds) from the inside of vehicles that were experimented with sedans and RVs (Recreational Vehicles) delivered from warehouses after 15, 30, 45 and 60 days. The value of TVOC (Total Volatile Organic Compounds) was twice to eight times over than the standard value. However, TVOC of vehicles was more detected than RVs. Especially, the value of toluene was rapidly decreased after 45 days. But after 60 days, it was more detected than the standard value. After 45 days, the xylene value was confirmed to be lower than the standard value. As a result, it was found that development of alternative technologies such as non-solvent and systems for automobile interior parts may be imminent. Using test method standard, although it is not yet International Standard, to analyze and replace components, concentrations, human-noxious, it will contribute to producing environmental-friendly vehicles.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.9
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• pp.63-69
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• 1998

In this paper, we propose a new Bit-Rate control algorithm based on bit usage matching to substitute encoded GOP(s) for new GOP(s) in MPEG-2 bitstream. It iteratively encodes current picture according to quantization value of previous picture and records bit-usage of each slice until nearly target bits are used. With target bits falling in two output bits, quantization value of slice should be changed to alleviate output bit error. We use recorded bit-usage information to decide which slices should be encoded with one quantization value and others with another. As every macroblock has different activity, we change macroblock quantization value using slice quantization value and activity value. The simulation results demonstrate that the fluctuation of the output bits can be kept within few-several tens of bits while maintaining the quality of the reconstructed pictures at a relatively stable level.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.96-96
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• 2019

Sedum kamchaticum, Sedum middendorffianum and Sedum takesimense belong to the sebum species. Especially, Sedum takesimense is a Korean native species growing only on Ullenung-do. Few studies for the biological activities of these plants have been reported. In this study, we examined biological activity and the contents of functional components of the aerial part and the root part of Sedum kamchaticum, Sedum middendorffianum and Sedum takesimense. As the results, the roots of Sedum takesimense showed the highest total phenolic contents (TPC : $13040{\pm}50.0mg\;GAE{\cdot}100g^{-1}$), and the aerial part of Sedum takesimens showed the highest total flavonoid contents (TFC : $2722.2{\pm}107.1mg\;CAE{\cdot}100g^{-1}$). Meanwhile, Sedum middendorffianum exhibited the highest anti-oxidant activity (DPPH $RC_{50}$ value of aerial part : $50.69{\pm}0.75{\mu}g{\cdot}mL^{-1}$, DPPH $RC_{50}$ value of root part : $27.27{\pm}0.55{\mu}g{\cdot}mL^{-1}$; ABTS $RC_{50}$ value of aerial part : $11.32{\pm}0.38{\mu}g{\cdot}mL^{-1}$, ABTS $RC_{50}$ value of roots part $5.54{\pm}0.02{\mu}g{\cdot}mL^{-1}$). The root part of Sedum middendorffianum showed the potent alpha glucosidase inhibitory activity (AGI $IC_{50}$ : $60.69{\pm}0.72{\mu}g{\cdot}mL^{-1}$). In order to elucidate active principle of Sedum middendorffianum that was shown the most potent antioxidant and anti-diabetic activities, the methanol extract of Sedum middendorffianum was fractionated with various solvents according to the polarity successively. As a result, EtOAc fraction of Sedum middendorffianum showed the highest contents of functional components (TPC : $16245.8{\pm}1025.7mg\;GAE{\cdot}100g^{-1}$, TFC : $4850.4{\pm}182.9mg\;CAE{\cdot}100g^{-1}$). And it also showed excellent anti-oxidant activities (DPPH $RC_{50}$ : $14.0{\pm}0.6{\mu}g{\cdot}mL^{-1}$, ABTS $RC_{50}$ : $3.4{\pm}0.1{\mu}g{\cdot}mL^{-1}$) and anti-diabetic activity (AGI $IC_{50}$ : $79.0{\pm}2.2{\mu}g{\cdot}mL^{-1}$). Above results suggest that Sedum middendorffianum can be developed to health functional material as a plant resource with potent antioxidant activity.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.390.1-390.1
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• 2016

The present work explains the interfacial energetics of all oxide transparent photodiodes. The optical, structural and morphological of copper oxides were systematically analyse by UV-Visible spectrometer, X-Ray diffraction, Raman spectroscopy, Scanning electron microscopy (SEM) and Atomic force microscopy measurements (AFM). The UV-Visible result exhibits optical bandgap of Cu2O and CuO as 2.2 and 2.05 eV respectively. SEM and AFM result shows a uniform grain size distribution in Cu2O and CuO thin films with the average grain size of 45 and 40 nm respectively. The results of Current-Voltage and Kelvin probe force microscope characteristics describe the electrical responses of the Cu2O/ZnO and CuO/ZnO heterojunctions photodiodes. The obtained electrical response depicts the approximately same knee voltages with a measurable difference in the absolute value of net terminal current. More over the present study realizes the all oxide transparent photodiode with zero bias photocurrent. The presented results lay the template for fabricating and analysing the self-bias all oxide transparent photodetector.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.1
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• pp.9-17
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• 2020

Currently, Storage Reliability is analyzed when predicting the reliability of guided missile. However, Mission Reliability and Logistics Reliability should be analyzed according to the definition of reliability in MIL-STD-785B. Therefore, it is necessary to accurately predict the reliability of guided missile based on the definition of reliability. In this paper, we proposed improved the reliability procedure and model for guided missile based on which the definition of reliability considering the mission profile. The proposed model can calculate the final failure rate by applying the ratio of the dormant and storage according to the mission profile. The proposed model has been confirmed to be more accurate than the existing model compared to the actual failure rate value. The results of this study can be useful for applying the reliability prediction to any guided missile.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.283-293
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• 2016

Owing to an increase in the air tightness of recent buildings, the natural ventilation rate was significantly lowered and the removal of accumulated moisture became difficult in these buildings. The hygrothermal performance of these buildings should be carefully considered to provide comfortable indoor environment by removing the moisture condensation risk and the mold growth potential. In this study, hygrothermal performance of two selected wall structures was investigated based on WUFI simulation program. The results displayed that the indoor temperature had impact on the moisture accumulation in the insulation layer for both modeled walls, showing that lower indoor temperature resulted in higher moisture accumulation, especially in the wood frame structure. Also, the yearly moisture accumulation profile exhibited a downward shift throughout the year by adding a vapour retarder with a lower sd-value. In addition, both of the two walls have condensation risk in winter, due to low temperature level. The wood frame structure has a bigger fluctuation and higher condensation risk than the concrete structure.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.245-252
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• 2004

When some enormous earthquake hazards broke out in the neighboring Japan and Taiwan, many Korean earthquake engineers thought that seismic guidelines must be adjusted safely and economically to consider the moderate earthquake characteristics. In the present aseismic guideline for liquefaction potential assessment, a simplified method using SPT-N value and a detail method based on the dynamic lab-tests were introduced. However, it is said that these methods based on the equivalent stress concept to simplify an irregular earthquake are not reliable to simulate the kaleidoscopical characteristics of earthquake loading correctly. Especially, even though various data from the dynamic lab-test can be obtained, only two data, a maximum cyclic load and a number of cycle at an initial liquefaction are used to determine the soil resistance strength in the detailed method. In this study, a new assessment of liquefaction potential is proposed and verified. In the proposed assessment, various data from dynamic lab-tests are used to determine the unique soil resistance characteristic and a site specific analysis is introduced to analyze the irregular earthquake time history itself. Also, it is found that the proposed assessment is reasonable because it is devised to reflect the changeable soil behavior under dynamic loadings resulted from the generation and development of excess pore water pressure.

• Journal of Electrochemical Science and Technology
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• v.11 no.4
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• pp.323-329
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• 2020

The cathodic hydrogen evolution ability of different pure metals and their long term galvanic corrosion behavior with pure Mg were investigated. The hydrogen evolution ability of pure Ti, Al, Sn and Zr is weak, while that of Fe, W, Cr, and Co is very strong. Initial polarization test could not completely reveal the cathodic behavior of the tested metals during long term corrosion. The cathodic hydrogen evolution ability may vary significantly in the long term galvanic tests for different metals, especially for Al whose cathodic current density reduced to 1/50 of the initial value. The anodic polarization shows that Al and Sn as alloying elements are supposed to provide relatively good passive effect for Mg alloy, while Ag can provide a slight passive effect and Zn has little passive effect.