• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.4
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• pp.431-439
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• 2010

Cross-interferometic synthetic aperture radar (CInSAR) technique from ERS-2 and Envisat images is capable of generating submeter-accuracy digital elevation model (DEM). However, it is very difficult to produce high-quality CInSAR-derived DEM due to the difference in the azimuth and range pixel size between ERS-2 and Envisat images as well as the small height ambiguity of CInSAR interferogram. In this study, we have proposed an efficient method to overcome the problems, produced a high-quality DEM over northern Alaska, and compared the CInSAR-derived DEM with the national elevation dataset (NED) DEM from U.S. Geological Survey. In the proposed method, azimuth common band filtering is applied in the radar raw data processing to mitigate the mis-registation due to the difference in the azimuth and range pixel size, and differential SAR interferogram (DInSAR) is used for reducing the unwrapping error occurred by the high fringe rate of CInSAR interferogram. Using the CInSAR DEM, we have identified and corrected man-made artifacts in the NED DEM. The wave number analysis further confirms that the CInSAR DEM has valid Signal in the high frequency of more than 0.08 radians/m (about 40m) while the NED DEM does not. Our results indicate that the CInSAR DEM is superior to the NED DEM in terms of both height precision and ground resolution.

• Pediatric Infection and Vaccine
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• v.19 no.1
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• pp.12-18
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• 2012

Purpose : This study attempted to investigate the frequency, duration, and risk factors of antibiotic-associated diarrhea (AAD) in infants hospitalized due to febrile urinary tract infection (UTI). This is a basic research on the probiotics used in the prevention and treatment of AAD in infants. Methods : Medical records of the infants aged 3-6 months hospitalized in Gachon University Gil Hospital from January 2008 to September 2010 due to the febrile UTI were retrospectively reviewed. The episodes of loose or watery stool were investigated for frequency, onset, and duration. Those who had AAD and those who did not (non-AAD) were compared. The antibiotic regimens and the episodes of diarrhea were investigated in AAD group. Result : Total 147 infants were included. Fifty-four (36.7%) showed AAD. Intravenous third-generation cephalosporin ($3^{rd}$ CS) single therapy was used for 102 patients (69.4%), the $3^{rd}$ CS and non-$3^{rd}$ CS combination therapy for 24 (16.3%), and non-$3^{rd}$ CS combination therapy for 21 (14.3%). There was no significant difference in the dose of cefotaxime between AAD and non-AAD group (P=0.601). According to the antibiotic therapies above, in AAD group, there was no significant difference in the onset and duration of diarrhea respectively (P=0.717, P=0.830). Although the frequency of diarrhea was higher for the $3^{rd}$ CS and non-$3^{rd}$ CS combination therapy subgroup with $9.25{\pm}5.30$ times/day than the other two subgroups ($7.58{\pm}2.97$ times/day in $3^{rd}$ CS single therapy subgroup, $6.75{\pm}4.40$ times/day in non-$3^{rd}$ CS combination therapy subgroup), there was no statistical significance (P=0.078). Conclusion : AAD seems common to the infants aged 3-6 months with febrile UTI, regardless of regimen and amount of antibiotics in usual dosage. Further research on the effects of probiotics used in the prevention and treatment of AAD in infants is warranted.

• Journal of Yeungnam Medical Science
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• v.16 no.1
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• pp.85-93
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• 1999

Some reports have shown a decreased effectiveness of extracorporeal shock wave lithotripsy(ESWL) with newer lithotriptors. We compared the treatment results of ESWL with a second generation Northgate SD-3 and a third generation Modulith SLX device. A total of 2,000 patients underwent ESWL treatments for single urinary calculus between September, 1988 and July, 1998. 1,241 patients were treated with Northgate SD-3 between September, 1988 and December, 1995. And 759 patients were treated with Modulith SLX between January, 1996 and July 1998. The treatment results were compared using chi-square test to determine statistical significance. The overall success rate, success rate according to the location and size, the mean number of sessions, complication rate and retreatment rate were calculated, according to lithotriptor. The overall success rate was 90.6% with Northgate SD-3 and 89.1% with Modulith SLX. With Northgate SD-3 and Modulith SLX, the success rate according to the location was 91.0%(579/636) and 88.1%(236/268) in kidney: 93.2%(517/555) and 89.9%(258/287) in upper ureter: 83.3%10/12) and 94.4%167/177) in middle and lower ureter: 47.4%(18/38) and 55. 6%(15/27) in staghorn stone, respectively. The success rate according to the size of stone with Northgate SD-3 and Modulith SLX for stones with the size under 10mm was 96.1%(612/637) and 93.1%(470/505); from 11mm to 20mm was 87.3%(421/482) and 86.4%(165/191); from 21mm to 30mm, 77.5%(62/80) and 67.5%(23/34): and for stones larger than 31mm was 69%(29/42) and 62.1%(18/29), respectively. Mean number of sessions for successful fragmentation was 1.21 and 1.69, respectively with Northgate SD-3 and Modulith SLX. Retreatment rate was 16.7% and 17.5%, respectively. The complications after treatment were severe pain(6.2% with Northgate SD-3 vs. 2.0% with Modulith SLX), steinstrasse(3.4% vs. 1.9%), fever(1.2% vs. 0.5%) and perirenal hematoma(0.2% vs. 0%) in order of frequency. There was no significant difference in the effectiveness of Northgate SD-3 and Modulith SLX. However, a statistically significant difference was observed between the two lithotriptors. We concluded that ESWL with Modulith SLX is more safe compared to Northgate SD-3.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.5
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• pp.346-355
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• 2005

To investigate the application of biochemical markers' and small-sample methods using whole-wheat flours for screening in early generation in Korean wheat breeding system, 74 Korean wheats, including cultivars, local breeding lines and experimental lines, were analyzed. Seed storage protein and amylose contents of grains were evaluated. Biochemical makers, including granule bound starch synthase (GBSS), high molecular weigh glutenin subunits (HMW-GS) and friabilin were also evaluated by using one-dimensional sodium dodecyl sulfate-polyacryla-mide gel electrophoresis with a single kernel. The small­sample methods, including modified SDS-sedimentation test (MST), micro-alkaline water retention capacity (AWRC) and whole-wheat flour swelling volume (WSV) were also tested in this study. Protein content, MST and AWRC was $11.0 - 15.8\%$, 2.7 - 26.2 ml and $71.9 - 109.7\%$, respectively. Apparent and total amylose content and WSV was $20.6 - 25.0\%$, $26.1 - 32.4\%$ and 9.0 - 16.9 ml, respectively. There were highly significant correlations between MST and AWRC (r=0.592, P<0.001), but Korean wheats showed no significant difference in protein content, amylose content and small-sample methods. In the biochemical markers, Korean wheats contained all three GBSS encoded by Wx loci, except for Suwon 252. Korean wheats showed the high frequency ($58.1\%$) of 1Dx2.2 + 1Dy12 subunits of HMW-GS. Friabilin band was present in 46 lines ($62.2\%$) and absent in 28 lines ($37.8\%$). Friabilin-absence lines showed the higher MST (14.9 ml) and AWRC ($92.1\%$) value than friabilin-presence lines (8.5 ml and $82.4\%$, respectively).

• Journal of Radiation Protection and Research
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• v.37 no.1
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• pp.1-9
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• 2012

A year has passed since the nuclear power plant accident in Fukushima on March 11, 2011, and a survey for public perception on radiation by Korean people has been made. The methodological design was based on a quantitative survey and a frequency analysis was done. The analysis objects were survey papers (n=2,754pcs) answered by random ordinary citizens chosen from all over the country. The questionnaires, and study tool, were directly distributed and collected. A total of 40 questionnaires using a coefficient of Cronbach's ${\alpha}$ per each area was 'self perception of radiation' (0.620), 'radiation risk' (0.830), 'benefit from radiation' (0.781), 'radiation controlled' (0.685), 'informative source of radiation' (0.831), 'influence degree from Fukushima accident' (0.763), showing rather high score from all areas. As the result of the questionnaires, the knowledge of radiation concept was 69.50 out of 100 points, which shows a rather significant difference from the result of 'know well about radiation' (53.7%) and 'just know about radiation' (37.40%). According to the survey, one of the main reasons why radiation seems risky was that once exposed to radiation, it may not have negative impacts presently but, the next generation could see negative impacts (66.1%). About 41% of our respondents showed a negative position against the government's report on radiation while 39.5% of respondents said that we should stop running nuclear power in light of Fukushima nuclear power plant accident. This study was done for the first time by Korean people's public perception on radiation after the Fukushima nuclear power plant accident. We expect this might have significant contributions to the establishment of the government's policy on radiation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.21 no.1
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• pp.12-18
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• 1985

In general the impulse sound sources of underwater generated by electric arc discharge had used static energy of the charged capacitors. The author proposed an underwater arc discharge sound source using secondary voltage of high voltage transformer without capacitors. The arc discharge device was composed of a high voltage transformer and a switching system. The impulse current in the primary turn of the high voltage transformer is controlled by the switching system and inductive current of the secondary turn in the high voltage transformer is used in making impulsive arc discharge. A series of experiment have been carried out to observe the acoustic characteristics of the impulse sound source generated by the arc discharge. The results obtained were as follows: 1. Secondary current at the time of arc discharge keeps after ohm's law in the beginning and the maximum current flows out as soon as arc discharge breaks out. 2. A time difference between a start of applied current and a generation of arc discharge sound is the 3msec and it is generated arc sound when breaking down electric insulation at maximum voltage. 3. The sharper the end of electrodes and the higher the secondary voltage, the higher the sound pressure level. 4. Arc discharge sound was generated even at the distance of 100cm between electrodes and was stably reproductive at the gap of 1cm to 100cm. 5. Electric arc discharge sound wave is a shock wave of pulse-width of 0.15msec and spectral distribution of it is plenty of low frequency components less than 10 KHz.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.3
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• pp.125-133
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• 2017

Time comparison is necessary for the verification and synchronization of the clock. Two-way satellite time and frequency (TWSTFT) is a method for time comparison over long distances. This method includes errors such as atmospheric effects, satellite motion, and environmental conditions. Ionospheric delay is one of the significant time comparison error in case of the carrier-phase TWSTFT (TWCP). Global Ionosphere Map (GIM) from Center for Orbit Determination in Europe (CODE) is used to compare with Bernese. Thin shell model of the ionosphere is used for the calculation of the Ionosphere Pierce Point (IPP) between stations and a GEO satellite. Korea Research Institute of Standards and Science (KRISS) and Koganei (KGNI) stations are used, and the analysis is conducted at 29 January 2017. Vertical Total Electron Content (VTEC) which is generated by Bernese at the latitude and longitude of the receiver by processing a Receiver Independent Exchange (RINEX) observation file that is generated from the receiver has demonstrated adequacy by showing similar variation trends with the CODE GIM. Bernese also has showed the capability to produce high resolution IONosphere map EXchange (IONEX) data compared to the CODE GIM. At each station IPP, VTEC difference in two stations showed absolute maximum 3.3 and 2.3 Total Electron Content Unit (TECU) in Bernese and GIM, respectively. The ionospheric delay of the TWCP has showed maximum 5.69 and 2.54 ps from Bernese and CODE GIM, respectively. Bernese could correct up to 6.29 ps in ionospheric delay rather than using CODE GIM. The peak-to-peak value of the ionospheric delay for TWCP in Bernese is about 10 ps, and this has to be eliminated to get high precision TWCP results. The $10^{-16}$ level uncertainty of atomic clock corresponds to 10 ps for 1 day averaging time, so time synchronization performance needs less than 10 ps. Current time synchronization of a satellite and ground station is about 2 ns level, but the smaller required performance, like less than 1 ns, the better. In this perspective, since the ionospheric delay could exceed over 100 ps in a long baseline different from this short baseline case, the elimination of the ionospheric delay is thought to be important for more high precision time synchronization of a satellite and ground station. This paper showed detailed method how to eliminate ionospheric delay for TWCP, and a specific case is applied by using this technique. Anyone could apply this method to establish high precision TWCP capability, and it is possible to use other software such as GIPSYOASIS and GPSTk. This TWCP could be applied in the high precision atomic clocks and used in the ground stations of the future domestic satellite navigation system.

• Journal of Families and Better Life
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• v.2 no.1
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• pp.111-129
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• 1984

The purpose of this study is to make a model of Family Life Cycle in Korea now. Answers to a questionnaire were collected from 724 housewives in Seoul area, 232 housewives in big cities, 203 housewives in small cities. The questionnaire contained 10 items about family situations,. Analyzing method employed for modeling to family life cycle are frequency, percentage, X2 -test . Results and findings are as follows; 1) The mean of first marriage age is 22.4yrs old. 23.5yrs old is the result of statistical materials published by E.P.B. 1975. The age of first marriage is higher according to the age, education & residential area. 2) The mean of first baby bearing age is 24.2 yrs old (generally 1 year after marriage). This age is the same as the result of statistical materials published by E.P.B. 3) the mean of last baby berating age is 32.6 yrs old compared to the E.P.B. statistical materials 3 yrs. low. This age is very different according to the age, education & residential area. 4) The mean of first child marriage age is 46.4 yrs old compared to the E.P.B. statistical materials 2.5 yrs old low. 5) the mean of last marriage age is 52.7 yrs old. this age is also 2.3 yrs low compared to the result of E.P.B. materials. 6) The number of child & interval is quite different according to the result of family planning generation of not. 7)According to the wife's employment, it does not show and difference. 8)The result of analyzing by F.L.C.,, we don't have launching stage & middle age stage apparently. So, we can make model of F.L.C. in Korea as follows (it will be change). 1) Establishment stage; from marriage to first baby born (23yrs old -24yrs old). 2) Child bearing & rearing stage; form first baby born to first child enter primary school(24 yrs old-30 yrs old). 3) Families with children's education stage; from first child primary school to high school graduation (30 yrs old-42yrs old) 4)Families with adult children stage; form first child got army college or stay at home(42 yrs- 48 yrs old). 5)Families with children's marriage stage; from first child marriage to last child marriage (48yrs old-57yrs old). 6) Aging stage; from last child marriage to self dying.

• 한국해양학회지
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• v.29 no.2
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• pp.152-163
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• 1994

The characteristics and fluctuations of structures and spatial distributions of warm eddies (anticyclonic eddies) in the southwestern part of the East Sea (the Japan Sea) are discussed based on the data gathered y the Fisheries Research and Development Agency, Korea from 1967 to 1968. The warm eddies existed very often in the southwest of the Ullung Island. The warm eddies are elliptical in shape and the mean size is about 130 km in diameter. Bimonthly distributions of warm eddies, the largest value of observed frequency and diameter in August and the least in June, indicate that the generation of the warm eddy is related with the development of the East Korean Warm Current. The warm eddies move west, north or southward with 0.80∼2.50 cm/sec or stay over a few months at the same place southwest of the Ullung Island. Movement of warm eddies may be influenced by the neighboring currents, the Rossby wave and the topography. The relationship between the position of warm eddies and the bottom topography suggests that the development and the movement of warm eddies are controlled by the Ullung Basin. The warm eddies should be divided into two groups. One group is the shallow warm eddy with strong baroclinic characteristics and the other is the deep one with strong Barotropic characteristics. The shallow group seems to be closely related with positive values (in summer) of the sea level difference between Pusan and Mozi (the Tsushima Current), while the deep group has no relation with that.

• Journal of IKEEE
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• v.22 no.4
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• pp.1006-1011
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• 2018

This paper proposes a three level buck converter utilizing multi-bit flying capacitor voltage control. The conventional three-level buck converter can not control the flying capacitor voltage, so that the operation is unstable or the circuit for controlling the flying capacitor voltage can not be applied to the PWM mode. Also when the load current is increased, an error occurs in the inductor voltage. The proposed structure can control the flying capacitor voltage in PWM mode by using differential difference amplifier and common mode feedback circuit. In addition, this paper proposes a 3bit flying capacitor voltage control circuit to optimize the operation of the three level buck converter depending on the load current, and a triangular wave generation circuit using the schmitt trigger circuit. The proposed 3-level buck converter is designed in $0.18{\mu}m$ CMOS process and has an input voltage range of 2.7V~3.6V and an output voltage range of 0.7V~2.4V. The operating frequency is 2MHz, the load current range is 30mA to 500mA, and the output voltage ripple is measured up to 32.5mV. The measurement results show a maximum power conversion efficiency of 85% at a load current of 130 mA.