• Proceedings of the KSRS Conference
• /
• 2005.10a
• /
• pp.542-545
• /
• 2005

Spaceborne radar interferometry has been widely used to estimate the topography and deformation of the Earth. It is difficult to obtain coherent interferometric SAR pairs especially over coastal areas mainly because of variation of surface conditions. We carried out the experiment using a cross-interferometric pair with a perpendicular baseline of about 1.4 km, a 30 minutes temporal separation and the height sensitivity of about 6 meters. The temporal decorrelation can be reduced by the cross interferometric technique with a 30 minutes temporal separation. Accurate coregistration was performed through resampling of ENVISAT ASAR data to equivalent pixel spacing to the ERS SAR data, because of the differences of the pulse repetition frequency and range sampling rate between the two sensors. Then we estimated range and azimuth offset to a sub-pixel accuracy using image intensity cross correlation. A larger window chip size than a general case was used because it was difficult to distinguish typical features. As range bin increased, the difference of Doppler centroid also increased. It resulted in lower coherence in far range than in near range. Coherences over wetland in near and far range were about 0.8 and 0.5, respectively. The coherence was improved by applying azimuth and range common band filtering, but coherence gap still existed. ERS-ENVISAT cross-interferogram usually lost information in urban area. However, high coherence over a city in this pair was shown, because of less man-made structures than other major cities. Accuracy of the DEM constructed by the ERS-ENVISAT 30-minute pair in a coastal area is to be evaluated.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.13 no.2
• /
• pp.98-107
• /
• 2013

This work describes a 13b 100 MS/s 0.13 um CMOS four-stage pipeline ADC for 3G communication systems. The proposed SHA-free ADC employs a range-scaling technique based on switched-capacitor circuits to properly handle a wide input range of $2V_{P-P}$ using a single on-chip reference of $1V_{P-P}$. The proposed range scaling makes the reference buffers keep a sufficient voltage headroom and doubles the offset tolerance of a latched comparator in the flash ADC1 with a doubled input range. A two-step reference selection technique in the back-end 5b flash ADC reduces both power dissipation and chip area by 50%. The prototype ADC in a 0.13 um CMOS demonstrates the measured differential and integral nonlinearities within 0.57 LSB and 0.99 LSB, respectively. The ADC shows a maximum signal-to-noise-and-distortion ratio of 64.6 dB and a maximum spurious-free dynamic range of 74.0 dB at 100 MS/s, respectively. The ADC with an active die area of 1.2 $mm^2$ consumes 145.6 mW including high-speed reference buffers and 91 mW excluding buffers at 100 MS/s and a 1.3 V supply voltage.

• Journal of Environmental Science International
• /
• v.15 no.7
• /
• pp.695-699
• /
• 2006

This study is to investigate the relationship between pore structures of activated carbons and adsorption characteristics of toluene vapor using dynamic adsorption method. The surface areas of below $10{\AA}$ in the pore diameter of activated carbons used in this experiment were in the range of 72 -93 % of total cumulative surface area and the toluene vapor equilibrium adsorption capacities were in the range of 350 - 390mg/g. Activated carbons having larger toluene adsorption capacity than the compared activated carbons had relatively pores in the pore diameter range of $7-10{\AA}$. Linear relationship between equilibrium adsorption capacity and cumulative sur- face area was in the diameter range of over $7{\AA}$. It was thought that toluene vapor was relatively well adsorbed on surfaces of pores of over $7{\AA}$.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.58 no.4
• /
• pp.602-608
• /
• 2009

In this thesis, output voltage, current and power of solar module were classified by irradiation from data of overall operating characteristics collected for one year in order to manage efficient photovoltaic generation system and deliver maximum power. In addition, from these data, correlations between irradiation of photovoltaic cell and amount of power given by photovoltaic cell was quantitatively examined to deduce optimization of the design and construction of photovoltaic generation system. As I-V characteristics according to a temperature range of 10~50[$^{\circ}C$], the area of I-V characteristics were increased with an increase in temperature. Since this area corresponds to the power, output power is thought to have increased with temperature. As output power characteristics according to a temperature range of 10~50[$^{\circ}C$], output power was increased with an increase in temperature. Since output power increases with temperature increase, the result corresponds well to the related equation on temperature and output power. As I-V characteristics according to a irradiation range of 100~900 [$W/m^2$], voltage and current were increased with an increase in irradiation. The result is thought of as an increase in output power with increasing irradiation. As output power characteristics according to a irradiation range of 100~900 [$W/m^2$], output power was increased with increasing irradiation. This result corresponds well to the related equation on irradiation and output power.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.15 no.1
• /
• pp.1-8
• /
• 1986

Authors investigatigated the analysis heavy metals in corps at the Mankyung river area. Samples were digested with Cone. nitric acid and Cone. hydroc hrorico acid and analyzed by Varian 875 Atomic Absorption Atomic Absorption Spectrophotometer in 1984. The results were as follows: The contents of heavy metals in rice were in the range of $0.41{\sim}5.15,\;1.12{\sim}5.18,\;10.65{\sim}14.54,\;24.15{\sim}35.41ppm$ for Pb, Cu, Mn, Zn respectively. Those in barley were in the range of $0.48{\sim}0.8,\;1.39{\sim}2.81,\;9.69{\sim}14.89,\;30.14{\sim}34.84ppm$ for Pb, Cu, Mn, Zn respectively. Those in kidney bean were in the range of $0.06{\sim}0.13,\;3.65{\sim}6.25,\;.65{\sim}12.15,\;51.25{\sim}65.69\;ppm$ for Pb, Cu, Mn, Zn respectively. Those in corn were in the range of $0.59{\sim}0.89,\;2.15{\sim}2.83,\;6.01{\sim}10.15,\;29.31{\sim}36.15ppm$for Pb, Cu, Mn, Zn respectively. We might be concluded that the above values of heavy metals contained in crop at the sites near to Mankyung river were serious partially.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1340-1352
• /
• 2008

In this study, S-wave velocity range is gauged in every field test method at the total 5 locations in the marine deposits in Incheon area. field test method is accomplished the SPT(Standard Penetration Test), CPT(Cone Penetration Test), SPS(Suspension PS Logger), SCPT (Seismic Cone Penetration Test) and so on. The S-wave velocity of SCPT in the downhole test method is measured lower than SPS logger at the N value > 15 range. But at the N value < 15 range, SPS logger and SCPT result is measured same. In this result, although the soil strength of the downhole test method increased, the rate of S-wave velocity is tend to be slowed. This result shows that the downhole test is difficult to apply at the place that the intensity of soil is more extreme and harder soil. And it shows that the existing Imai(1982) type that is mostly used within the country is not suitable for the marine deposits. Thus, the empirical formula that can show the range of S-wave velocity in each N value for domestic soil is needed.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.22 no.6
• /
• pp.832-840
• /
• 2019

Recently, pollution from gunpowder due to shell shootings at military drilling sites has raised various environmental concerns. The purpose of this study is to predict the contamination level of RDX in the soil area of the firing range zone near Anwol river watershed, the study site, and the intake area, Anwol river and Imjin river, as a function of time and space. In this study, a multimedia model was developed to predict the variation of RDX contamination by rainfall. The range of the medium was limited to soil, water, and sediment, and excluded the atmosphere, taking into account the physical and chemical properties of RDX with low vapor pressure and low Henry's constant. The pollutant levels of the waters of compartments, including the last section of the Imjin River affecting the water intake, was compared with the environmental standard for RDX.

• Journal of Korean Society for Geospatial Information Science
• /
• v.18 no.2
• /
• pp.55-61
• /
• 2010

Using 3D point data implemented from terrestrial LiDAR, this research has modelled geospatial data in 2 categories(gridded & un-gridded) and conducted LOS analysis experiment using outcome from the modeling exercise. To compare LOS analysis results from each of the 2 models in the above, maximum LOS (line of sight) range in the experimental area was specified as 30m in Area A, 40m in Area B and 50m in Area C and the time taken by LOS analysis and the number of visible points were measured. As for the LOS analysis experiment results, in comparison with the gridded model, the un-gridded model took about 3.9 times more time in Area A, 5.4 times in Area B and 6.5 times in Area C. In addition, about 0.97 times fewer points were measured in Area A, 0.93 times in Area B and 0.94 times in Area C. The difference between gridded model and un-gridded model in terms of the time taken by LOS analysis increased, as the maximum LOS range extended. On the other hand, the number visible points did not vary significantly in reference to the size of visible range.

• Journal of the Korean Society of Radiology
• /
• v.15 no.2
• /
• pp.139-145
• /
• 2021

This study is to confirm the range of tube voltage for Chest X-ray in DR system by comparing with dose area product (DAP) and effective dose in efficient detector exposure index (DEI) range. GE definium 8000 was used to for the phantom study. The range of tube voltage is 60~130 kVp and of mAs is 2.5~40 mAs. The acquired images were classified into efficient DEI groups, then calculated effective dose with DAP by using a PC-Based Monte Carlo Program 2.0. The signal to noise ratio (SNR) was measured at 4 regions, including the thoracic spine, the lung area with the ribs, the lung area without the ribs, and the liver by using Picture Archiving and Communication System. The significance of the group for each tube voltage was verified by performing the kruskal-wallis test and the mann-whitney test as a post-test. When set to 4 groups dependned on the tube voltage, DAP showed significant differences; 60 kVp and 80 kVp, and 60 kVp and 90 kVp (p= 0.034, 0.021). Effective dose exhibited no statistically significant differences from the all of the group (p>0.05). SNR exhibited statistically significant differences from the all of the group in the liver except compared to 80 kVp and 90 kVp (p<0.05). Therefore, high tube voltages of 100 kVp or more need to be reconsidered in terms of patient dose and imaging in order to represent an appropriate chest X-ray image in a digital system.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.1497-1500
• /
• 2006

The cooling effect of paddy fields was compared with those of other land-use areas (upland, urban park, and urban residential area) during midsummer. The temperature were monitored using data logger at one hour intervals in study sites. Diurnal temperature range of study areas in clear days was larger than in cloudy days. Also, diurnal temperature ranges in paddy field, upland, and park areas were larger than those in the urban residential area during clear days. The paddy field or upland area has shown more remarkable cooling effect compared to urban residential areas: Mean duration of temperature below $25^{\circ}C$ in the paddy field area is longer(7 to 8 hours) than in the residential area; The time to fall to below $25^{\circ}C$ in the paddy field area is sooner than in the residential area; Mean daily minimum temperature in the paddy field area is much lower than in the residential area.