• Korean Journal of Remote Sensing
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• v.39 no.6_1
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• pp.1273-1281
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• 2023

Absolute radiometric calibration is a crucial process in converting the electromagnetic signals obtained from satellite sensors into physical quantities. It is performed to enhance the accuracy of satellite data, facilitate comparison and integration with other satellite datasets, and address changes in sensor characteristics over time or due to environmental conditions. In this study, field campaigns were conducted to perform vicarious calibration for the multispectral channels of the CAS500-1. Two valid field observations were obtained under clear-sky conditions, and the top-of-atmosphere (TOA) radiance was simulated using the MODerate resolution atmospheric TRANsmission 6 (MODTRAN 6) radiative transfer model. While a linear relationship was observed between the simulated TOA radiance of tarps and CAS500-1 digital numbers(DN), challenges such as a wide field of view and saturation in CAS500-1 imagery suggest the need for future refinement of the calibration coefficients. Nevertheless, this study represents the first attempt at absolute radiometric calibration for CAS500-1. Despite the challenges, it provides valuable insights for future research aiming to determine reliable coefficients for enhanced accuracy in CAS500-1's absolute radiometric calibration.

• Korean Journal of Weed Science
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• v.13 no.2
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• pp.159-163
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• 1993

This research was conducted at the Crop Experiment Station to determine the changes of weed flora under direct seeded rice cultivation in dry paddy field from 1989 to 1992 and to establish an effective weed control strategy in direct seeded rice cultivation. With the continuous rice growing under direct seeded rice cultivation in dry paddy field, there were more occurrence in grasses and annual weeds while broadleaf and perennial weeds were diminished. The predominant weeds were aquatic weeds such as Eleocharis kuroguwai, Echinochloa crusgalli, and Monochoria vaginalis in machine transplanted rice paddy field while there were predominant of semi aquatic weed species such as E. crusgalli, Digitaria sanguinalis, Bidens tripartita, Aeschynomene indica, and Arthraxon hispidus in continuous direct seeded rice cultivation in dry paddy condition. Based on the vegetative analysis of weeds in terms of simpson index and community dominance, there was more distribution of weed species in direct seeded rice cultivation on dry paddy condition while only distributed with 1-2 weed species in machine transplanted rice paddy field. In similarity coefficient, there was a gradual increase up to 67% of weeds with the continuous direct seeded rice cultivation in dry paddy condition for 4 years starting from 41% of similarity coefficient.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.3
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• pp.189-197
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• 2006

The influence of leodo Ocean Research Station structure to surrounding atmospheric flow is carefully investigated using CFD techniques. Moreover, the validation works of computational results are performed by the comparison with the observed data of leodo Ocean Research station. In this paper, we performed 3-dimensional CAD modelling of the station, generated the grid system for numerical analysis and carried out flow analyses using Navier-Stokes equations coupled with two-equation turbulence model. For suitable free stream conditions of wind speed and direction, the interference of the research station structure on the flow field is predicted. Beside, the computational results are benchmarked by observed data to confirm the accuracy of measured date and reliable data range of each measuring position according to the wind direction. Through the results of this research, now the quantitative evaluation of the error range of interfered gauge data is possible, which is expected to be applied to provide base data of accurate sea surface wind around research stations.

• 한국약용작물학회:학술대회논문집
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• 2011.09a
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• pp.400-401
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• 2011

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.1
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• pp.69-76
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• 2002

Mustard aphid, Lipaphis erysimi(Kalt.) plays a key role in determining the productivity of rapeseed-mustard. This pest alone attributes 30-70% losses in yield potential in different agro climatic zones with a mean loss of 54.2% in India. Considering the extent of damage caused by the pest, the present experiment was conducted at Pulses and Oilseeds Research Station during 1992-93 to 1994-95 to study the migratory nature of mustard aphid by trapping them in yellow colour pan tray and their simultaneous growth and development on three different genotypes. The temperature during noon hours is the predominant factor to govern the appearance of alate mustard aphid in rapeseed-mustard field. Stepwise regression analysis revealed that temperature and relative humidity played an important role for its development. The variety RW white flower glossy stem harboured minimum number of aphid in comparison to other two varieties B 9 and T6342. The population reached a peak of 61.28 aphids/10 cm central twig during $6^{th}$ standard week irrespective of varieties.

• Journal of information and communication convergence engineering
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• v.19 no.3
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• pp.131-135
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• 2021

The interference between closely placed co-coverage satellites was analyzed. In general, a satellite network may use different orthogonal polarizations and frequencies to increase the throughput of a satellite. However, when orthogonal linear polarization (horizontal polarization and vertical polarization) or orthogonal circular polarization (left-handed circular polarization and right-handed circular polarization) is used, the signal from one polarization sense to another may be coupled, resulting in cross-polarization interference. This signal-coupling arises due to the finite value of the cross-polarization discrimination of the earth station. In this study, field equations were used to analyze the interference between adjacent satellites using co-frequency. The level of interference was compared to that when two adjacent satellites used the same polarization. The simulation results show that the interference mainly depends on the off-axis co-polar pattern and the cross-polar pattern of the earth station antenna.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2885-2890
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• 2011

Simulation study were performed for fire location effect on the smoke spread in the deeply-underground subway station(DUSS). In this research, Shingumho station (The line # 5, Depth: 46m) has been selected as case-study for the analysis of smoke-spread effect with the different fire location. Field test data measured for actual fan in DUSS was applied as a condition of a simulation. The whole station was covered in this analysis and 4 million grids were generated for this simulation. The fire driven flow was analyzed case by case to compare the smoke-spread effect according to the fire location. In order to enhance the efficiency of calculation, parallel processing by MPI was employed and LES(large eddy simulation) method in FDS code was adopted.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.660-667
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• 2000

This paper aims at analyzing the traffic of CDMA base station. RTD(Round Trip Delay) method, used for the study, is one of the developed tool for calculating the call setup time between the BTS(Base Station TransceiverSubsystem) and mobile station.We compare the calculated call setup time in air with the field experiments.And we suggest the RTD method for dividing the traffic of the connected repeater from that of the BTS, andwe can testify it by the experiment which analyze the difference of the received time between the base stationand the repeater including the forced delay elements.

• Journal of Environmental Science International
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• v.11 no.4
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• pp.297-308
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• 2002

Field observations for research of oceanographic characteristics in waters adjacent to fish farm on land and water quality at area where water is supplied to fish farm and area where water is discharged from fish farm are carried out in coastal waters of Pyoson located in the southeastern region of Jeju Island in March, May, August and November of 2000. Semidiurnal tides to the northeast and southwest dominate. The mean velocities of current around neap tides and spring tides are 8.52cmㆍs$^{-1}$, 28.63cmㆍs$^{-1}$, respectively. The difference of temperature between area where water is supplied to fish farm and area where water is discharged from fish farm is about 0.6$^{\circ}C$. Seasonal variation range for temperature and salinity is 13.5$^{\circ}C$ and 3.5psu, individually. Concentrations of nitrate(NO$_3$$^{-}$), phosphate(PO$_4$$^{3-}$ ), silicate(SiO$_2$) and COD(chemical oxygen demand) are high in autumn. Particularly, concentrations of nitrate and COD in winter and spring at station where water is supplied to fish farm are higher than these at station where water is dischared from fish farm. However, concentration of phosphate and silicate at station where is supplied to fish farm in spring, summer and autumn is higher than that at station where water is dischared from fish farm. Water quality in the study area is grade 1 and this level is kept up in the whole year.

• Korean Journal of Veterinary Research
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• v.33 no.1
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• pp.81-85
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• 1993

Gel electrophoresis has proven to be one of the most useful of DNA separation and purification. The new technique of pulsed field gel electrophoresis (PFGE) is high resolution separation of large size DNA moleculs. Conventional continuous gel electrophresis can not be separation of large DNA fragments(20~50 k base). Field inversion gel electrophoresis(FIGE) is very useful for large DNA molecules. We have found that a pulse ratio ; 2 : 1, time ; 24hrs., volts ; $10^{volts}/_{cm}$, start ; 0.45sec, end ; 1sec, is most effectively resolves DNA fragment in the 6~50k base.