• Journal of Ginseng Research
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• v.12 no.1
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• pp.1-10
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• 1988

Panax ginseng seedlings were grown at various temperature regimes from 15 to $30^{\circ}C$ for 19 days under dark and the linear relationship between various regrowth efficiencies and thermal stress indices, cumulative superoptimum temperatures corrected with factors. Gross growth efficiency(shoot weight l root weight loss) was 37.5 % at the optimum temperature $15^{\circ}C$/$15^{\circ}C$, and 12.3% at the highest temperature, $30^{\circ}C$/$30^{\circ}C$ while net growth efficiency (shoot weight + Sm)l(root loss-Rm), which corrected by maintenance respiration for shoot(Sm) and root(Rm) was 39.6% and 16.7 at optimum and highest temperature respectively. All growth efficiencies showed negative correlations (p = 0.001) with all thermal stress indices and negative(p = 0.001) with shoot growth(St). When growth temperature difference in a day was nil or above $15^{\circ}C$ growth efficiency decreased greatly. Thermal stress indices showed negative correlation with root dry matter loss(RDL) but positive with Rm. St showed positive correlation with RDL. Thermal stress appeared to inhibit substrate supply for shoot growth resulting in the extremely low growth efficiency comparing with other crops that seems to be main rate limiting factor of slow growth, Thus it is necessary that growth efficiency and thermal stress must be elucidated in terms of metabolic pathway.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.3
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• pp.77-85
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• 2008

This work proposes a 12b 130MS/s 108mW $1.8mm^2$ 0.18um CMOS ADC for high-quality video systems such as TFT-LCD displays and digital TVs requiring simultaneously high resolution, low power, and small size at high speed. The proposed ADC optimizes power consumption and chip area at the target resolution and sampling rate based on a three-step pipeline architecture. The input SHA with gate-bootstrapped sampling switches and a properly controlled trans-conductance ratio of two amplifier stages achieves a high gain and phase margin for 12b input accuracy at the Nyquist frequency. A signal-insensitive 3D-fully symmetric layout reduces a capacitor and device mismatch of two MDACs. The proposed supply- and temperature- insensitive current and voltage references are implemented on chip with a small number of transistors. The prototype ADC in a 0.18um 1P6M CMOS technology demonstrates a measured DNL and INL within 0.69LSB and 2.12LSB, respectively. The ADC shows a maximum SNDR of 53dB and 51dB and a maximum SFDR of 68dB and 66dB at 120MS/s and 130MS/s, respectively. The ADC with an active die area of $1.8mm^2$ consumes 108mW at 130MS/s and 1.8V.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.531-540
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• 2016

The adoption of legume cover crops in no-tillage system can contribute to improve soil fertility by providing several benefits, including reduction in soil erosion, suppression of weed growth and N supply to subsequent crops. We conducted a field study to investigate the effect of cover crops and nitrogen fertilization rates on yield and nitrogen use efficiency of waxy corn (Zea mays L.) in no-tillage upland field. Two legume cover crops, hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnuturn L.) were mechanically terminated with roller in early June. For each cover crop treatment, nitrogen (N) fertilizer was applied at three different rates (145, 72.5 and $0kg\;N\;ha^{-1}$). The growth and yield characteristics of corn were significantly affected by the N fertilization rates in crimson clover plots, which suggest N mineralization from the cover crop residue was not sufficient. In contrast, N fertilization rates had no significant effect on growth and yield of corn in hairy vetch plots, indicating that the amount of N released from the cover crop is large enough to meet most of the N requirement of corn. However, the application of N fertilizer in hairy vetch cover plots resulted in slight increase of crop yield, though not statically significant, and high levels of N concentration in corn plant tissue possibly due to luxury consumption of N. Organic residues on the soil surface in hairy vetch cover plots had substantial amounts of N after harvest, ranging from 100 to $116kg\;N\;ha^{-1}$, which is presumably retained during winter season and released by microbial mineralization in subsequent year. The highest nitrogen yield efficiency was achieved in the plot with hairy vetch cover and no N fertilizer application, followed by the plot with hairy vetch cover and $72.5kg\;N\;ha^{-1}$ fertilization rate. In conclusion, hairy vetch showed better performance in corn productivity as compared with crimson clover. In addition, it was concluded that the application of N fertilizer between 0 and $72.5kg\;N\;ha^{-1}$ in combination with hairy vetch cover crop might be most efficient for corn yield under no-tillage system with climatic and soil characteristics similar to those of the experimental site.

• Clean Technology
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• v.22 no.4
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• pp.232-240
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• 2016

Recently, various research studies have been conducted and many are in progress for the suitable alternative materials for ITO based touch screen panel (TSP) due to limitations in size and flexibility. Various researches from all over the world have been attempted to fabricate the fine electrode less than $5{\mu}m$ for the rapid developing of display technology. Research is also being carried out in metal mesh methods using the existing technologies and alternative materials at commercial level. However, by using the existing technologies certain discrepancies are observed like low transparency and low yield which also results in the distortion of patterns. For repairing the damaged pattern, the conventional laser CVD technique has also been used but there are some challenges observed in CVD technique like achieving a stable fine electrode of $10{\mu}m$ or less and avoiding the formation of satellite drops. To overcome these issues, a new printing process named Electrohydrodynamic (EHD) printing, has been introduced by which $5{\mu}m$ fine patterns can be printed in one step. This EHDA printing technique has been applied to print very fine electrodes of $5{\mu}m$ or less by using conductive inks of various viscosities. This study also presents the optimized process parameters for printing $5{\mu}m$ fine electrode patterns during experiments by controlling the applied voltage and supply flow rate. The $5{\mu}m$ repair electrodes were fabricated for repairing $50{\mu}m$ shorted electrode samples.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.56-61
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• 2009

Paradigm depending only on fossil fuel for building heat source is rapidly changing. Accelerating the change, as it has been known, is obligation for reducing green house gas coming from use of fossil fuel, i.e. reaction to United Nations Framework Convention on Climate Change. In addition, factors such as high oil price, unstable supply, weapon of petroleum and oil peak, by replacing fossil fuel, contributes to advance of environmental friendly renewable energy which can be continuously reusable. Therefore, current new energy policies, beyond enhancing effectiveness of heat using equipments, are to make best efforts for national competitiveness. Our country supports 11 areas for new renewable energy including sun light, solar heat and wind power. Among those areas, ocean thermal energy specifies tidal power generation using tide of sea, wave and temperature differences, wave power generation and thermal power generation. But heat use of heat source from sea water itself has been excluded as non-utilized energy. In the future, sea water heat source which has not been used so far will be required to be specified as new renewable energy. This research is to survey local heating system in Europe using sea water, central solar heating plants, seasonal thermal energy store and to analyze large scale central solar heating plants in German. Seasonal thermal energy store necessarily need to be equipped with large scale thermal energy store. Currently operating central solar heating system is a effective method which significantly enhances sharing rate of solar heat in a way that stores excessive heat generating in summer and then replenish insufficient heat for winter. Construction cost for this system is primarily dependent on large scale seasonal heat store and this high priced heat store merely plays its role once per year. Since our country is faced with 3 directional sea, active research and development for using sea water heat as cooling and heating heat source is required for seashore villages and building units. This research suggests how to utilize new energy in a way that stores cooling heat of sea water into seasonal thermal energy store when temperature of sea water is its lowest temperature in February based on West Sea and then uses it as cooling heat source when cooling is necessary. Since this method utilizes seasonal thermal energy store from existing central solar heating plant for heating and cooling purpose respectively twice per year maximizing energy efficiency by achieving 2 seasonal thermal energy store, active research and development is necessarily required for the future.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.364-369
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• 1982

Two varieties of potatoes, Irish cobbler and Shimabara stored for seven and nine months respectively by irradiation combined with natural low temperature (year-round temperature change:$2{\sim}17^{\circ}C)$ on a batch scale were investigated on the suitability for processing of potato chip. Nine months after storage, irradiated potatoes (Irish cobbler) tended to maintain somewhat-better texture and sensory quality than untreated in potato chip processing. Peel rate, closely related to potato chip yield, of untreated potatoes were $20{\sim}25%$ higher than those of irradiated and Agtron color determination of potato chip from both irradiated were commercially acceptable. Preservation of potatoes by irradiation combined with natural low temperature was evaluated as an alternative method of the supply for raw materials of potato chip processing in the off season in Korea.

• The Journal of Korean society of community based occupational therapy
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• v.5 no.1
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• pp.45-53
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• 2015

Objective : The purpose of this study is to investigate the awareness and interest rate of residential environment and to establish basic data for further development of occupational therapy through the results. Methods : This survey was conducted between April 1th and May 31st 2015 and 165 questionnaires were public. The questionnaires of 165 respondents were analyzed through Cosstabs, Descriptive statistics, Frequency study and t-test, ANOVA analysis using SPSS ver. 18.0 Results : Looking for recognition percentage of residential environment improvement, 44.8% of people reply the changing the house structure and 26.8% of people reply the cure method. in contrast to 28.5% of people reply the architect, the only 9.1% of people reply occupation therapist. the most people agree that residential environment improvement is important. but there is no difference about answer between sex and age. 5.9% of people reply that improving live environments may be good for improving life quality but 7.6% of people reply independency may increase, it is not important because it must need lot of money for improving live environments Conclusion : The awareness of the residential environment improvement in short supply, but Things that are significant in the distance, the need for further residential environment improvement was broad consensus. residential environment improvement for people with disabilities in economic assistance and occupational therapists and incursion of correlated to require institutional support.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.6
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• pp.679-685
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• 2011

This paper presents an algorithm identifying devices that generate observed mixed signals that are collected at main power-supply line. The proposed algorithm, which is necessary for low cost electric power monitoring system at appliance-level, that is non-intrusive load monitoring system, divides incoming mixed signal into multiple time intervals, calculating difference-signals between consecutive time interval, and identifies which device is operating at the time interval by analysing the difference-signals. Since the features of one device can remain when the time interval is short enough and the features are independent and additive, well-known classification algorithms can be used to classify the difference-signals with features of N individual devices, otherwise $2^N$ features might be necessary. The proposed algorithm was verified using data mixed in a laboratory with individual devices's data collected from field. When maximum 4 devices operate or stop sequentially and when features satisfy the requirements of proposed algorithm, the proposed algorithm resulted nearly 100% success rate under the constrained test condition. In order to apply the proposed algorithm in real world, the number devices shall increase, the time interval shall be smaller and the pattern of mixture shall be more diverse. However we can expect, if features used follow guidelines of proposed algorithm, future system could have certain level of performance without the guideline.

• Journal of the Korea Institute of Building Construction
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• v.17 no.3
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• pp.227-234
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• 2017

This research analyzes the properties of mortar following the rise in water-cement ratio and applicability as an eco-friendly construction supply by using the mudflats of a dredged arena as a substitute for aggregate. The results of a experiment of the flow showed that the flow value decreases as the amount of mudflats increases. A test for chloride content showed that the chloride content increases with the amount of mudflats. In the compression of specimen mixed with mudflat and the testing of tensile strength, the strength weakened as the addition ratio of mudflats rose. However, with 14-day strength as the standard, most specimen showed more strength than the plain, and 14-day strength was higher than 28-day strength. It appears to be experimental error in the mixing process from the viscosity and cohesion of mudflats, and it is considered that there will be a need for an experiment on mixing methods of mudflats in the future. The compressive strength of this research was the strongest with 70% in water-cement ratio, and the tensile strength was strongest with 80% in water-cement ratio. In the evaluation of surface analysis, 70% water-cement ratio, which is finest in strength, mixing, and compactness, was selected to analyze the roughness of the surface, and the results showed that the surface became smoother as the addition ratio of mudflats increases. In conclusion, it appears that 70% water-cement ratio is the optimal mixing ratio for mortar and 10 to 30% addition ratio of mudflats the optimal ratio. It also appears that the application of interior finishing material like bricks and tiles and interior plastering material using the mudflats are possible.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.93-101
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• 2014

How to determine the extent of national energy security? In this paper, we estimate it by comparative analysis of South Korea and other OECD countries in terms of energy diversity (fuel diversity). Energy security consists of 4 key factors such as availability, accessibility, acceptability, affordability. Especially the importance of accessibility can grow as local imbalance of supply and demand increases. As a proxy of the accessibility, fuel diversity can be a significant indicator to estimate a measure of energy security. In this paper, we use Shannon-Wiener index to measure energy diversity. If fuel diversity increases, the stability of energy security also should increase, because of the smoothing effect to lessen dependence on key energy sources. In 2012 Korean growth rate of H-index (energy diversity) is 18.38%, which is higher than other OECD countries. However, Korean H-index itself is 1.93, lesser than other countries. Shift from oil to coals/gas within fossil fuels has more impact on H-index than weight transition from fossil fuels to renewable energies in Korea. We conclude that more renewable energy is an effective solution to achieve higher energy diversity and ultimately higher energy security as the same as the German case.