• Journal of Cadastre & Land InformatiX
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• v.44 no.2
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• pp.103-112
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• 2014

The objective of this study is to suggest the possibility on land cover classification using hyperspectal imagery on area which includes lands and waters. After atmospheric correction as a preprocessing work was conducted on hyperspectral imagery acquired by airborne hyperspectral sensor CASI-1500, the effect of atmospheric correction to a few land cover class in before and after atmospheric correction was compared and analyzed. As the result of accuracy of land cover classification by highspectral imagery using reference data as airphoto and digital topographic map, maximum likelihood method represented overall accuracy as 67.0% and minimum distance method showed overall accuracy as 52.4%. Also product accuracy of land cover classification on road, dry field and green house, but that on river, forest, grassland showed low because the area of those was composed of complex object. Therefore, the study needs to select optimal band to classify specific object and to construct spectral library considering spectral characteristics of specific object.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.1
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• pp.1-8
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• 2016

Temperature correction trans-membrane pressure (TC-TMP) is frequently used as a fouling index in membrane water treatment plants. TC-TMP equation is derived based on an assumption that the total membrane resistance (i.e. the sum of the intrinsic membrane resistance and fouling resistance) is not affected by temperature. This work verified the validity of this assumption using microfiltration (MF) and ultrafiltration (UF) membranes with and without fouling. The foulants used in the work were kaolin (inorganic) and humic acid (organic). The intrinsic resistances of MF and UF membranes remains at constant values regardless of temperature change. When the same amount of foulants were accumulated on the membrane, inorganic fouling resistance with kaolin was constant regardless of temperature change while organic fouling resistance with humic acid decreased at higher temperatures, which means that TC-TMP cannot be used as a fouling index when organic fouling occurs in a real field application. Since TC-TMP underestimates the amount of fouling at higher temperatures, more attention should be necessary in the operation of membrane water treatment plant in a hotter season like summer.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.2
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• pp.137-145
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• 2003

Currently, the availability of 3-D topographical survey by combination of GPS and Echo Sounder has been increased in the various field like as the construction of structure, the dredging and the reclamation in the ocean and river, and observation of topographic change in seabed or riverbed. In this case, the error of depth sounding can divide in form that is happened by combination of GPS and Echo Sounder, and form that is happened in Echo Sounder itself, In this study, in the case happen by Echo Sounder itself, analyzed error by specially about geological features of the seabed and riverbed that is specular surface of sound wave and wished to present solution way. The sounding error about the echo sounder and characteristic of estuary riverbed was found by understanding the relation of average diameter and residual error and we defined correction formula, Y=-0.00474$^{*}$In(X) -0.0045 by the regression analysis. and then we verified applicability of correction formula. As the result, if measure Preliminary investigation or pre-survey the geological features for the survey area at topographical survey of estuary riverbed, we presented the error correction formula that estimate and can correct of error by Echo Sounderer.

• Journal of Korean Society for Geospatial Information Science
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• v.1 no.1 s.1
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• pp.181-192
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• 1993

Image is composed of the digital numbers including information on natural phenomena, their condition and the kind of objects. Digital numbers change in geometric correction(that is preprocessing). This change of digital numbers gave an effect on results of land-cover classification. We intend to know the influence of resampling as classifying land-cover using the image reconstructed by geometric correction in this paper. Chun-cheon basin was selected the study area having most variable land-cover pattern in North-Han river valley and made on use of RESTEC data resampled in preprocessing. Land-cover is classified as six classes of LEVEL I using maximum likelyhood classification method. We classified land-cover using the image resampled by two methods in this study. Bilinear interpolation method was most accurate in five classes except bear-land in the result of comparing each class with topographic map. We should choose the method of resampling according to the class in which we put the importance in the image resampling of geometric correction. And if we use four-season's image, we may classify more accurately in case of the confusion in case of the confusion in borders of rice field and farm.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.2
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• pp.107-116
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• 2016

Airborne or spaceborne remote sensing can increase the efficiency of seabed material surveys compared with field surveying using a vessel. For the same seabed material, the optical remote sensing image shows variation in the reflectance depending on the water depth, which is due to the absorption and scattering by the water column. This study suggests a correction procedure to use the hyperspectral image for seabed material analysis. The study is conducted in the coastal area from Sacheonjin Port to Gyungpo Beach in Gangwon-do. The hyperspectral image is acquired using the CASI-1500 sensor. The diffuse attenuation coefficient is estimated for each band through regression models between the water reflectance and depth. Then, the coefficient is applied to each band of the image. As a result, the completely corrected image can be interpreted for a deeper area, although the interpretable area is very shallow without water column correction. Additionally, the water column corrected image shows decreased variation of reflectance with various water depths.

• Nuclear Engineering and Technology
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• v.47 no.7
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• pp.939-944
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• 2015

The calibration methods of neutron-measuring devices such as the neutron survey meter have advantages and disadvantages. To compare the calibration factors obtained by the shadow cone method and semi-empirical method, 10 neutron survey meters of five different types were used in this study. This experiment was performed at the Korea Atomic Energy Research Institute (KAERI; Daejeon, South Korea), and the calibration neutron fields were constructed using a $^{252}Californium$ ($^{252}Cf$) neutron source, which was positioned in the center of the neutron irradiation room. The neutron spectra of the calibration neutron fields were measured by a europium-activated lithium iodide scintillator in combination with KAERI's Bonner sphere system. When the shadow cone method was used, 10 single moderator-based survey meters exhibited a smaller calibration factor by as much as 3.1-9.3% than that of the semi-empirical method. This finding indicates that neutron survey meters underestimated the scattered neutrons and attenuated neutrons (i.e., the total scatter corrections). This underestimation of the calibration factor was attributed to the fact that single moderator-based survey meters have an under-ambient dose equivalent response in the thermal or thermal-dominant neutron field. As a result, when the shadow cone method is used for a single moderator-based survey meter, an additional correction and the International Organization for Standardization standard 8529-2 for room-scattered neutrons should be considered.

• Journal of the Korea Convergence Society
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• v.10 no.10
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• pp.15-21
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• 2019

X-rays with shorter wavelengths than ultraviolet light have very good penetration power. It is convergence in industrial and medical fields has been used a lot. n particular, in the industrial field, various researches have been conducted on the detection of foregin body inside metal that can occur in the production process of products such as metal using x-ray, a non-destructive inspection device. Detectors are becoming increasingly popular for the popularization of DR (Digital Radiography) photography methods that digitally acquire X-ray video images. However, there are cases where foreign body detection is impossible depending on the sensor noise and sensitivity inside the detector. When producing a metal product, since the defective rate of the produced product may increase due to contamination of the foreign body, accurate detection is necessary. In this paper, we provide a correction model for X-ray images acquired in order to improve the efficiency of defect detection such as foreign body inside metal. When applied to defect detection in the production process of metal products through the proposed model, it is expected that the detection of product defects can be processed accurately and quickly.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.707-716
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• 2020

Spectroradiometers have recently been drawing great attention in earth observing communities for its capability for obtaining target's quantitative properties. In particular, light-weighted multispectral cameras are gaining popularity in many field domains, as being utilized on UAV's. Despite the importance of the radiometric accuracy, studies are scarce on the performance of the inexpensive multispectral camera sensors that have various applications in agricultural, vegetation, and water quality analysis. This study conducted assessment of radiometric accuracy for MicaSense RedEdge-MX multispectral camera, by comparing the radiometric data with an independent hyperspectral sensor having NIST-traceable calibration quality. The comaprison showed that radiance from RedEdge-MX is lower than that of TriOS RAMSES by 5 to 16% depending on the bands, and the irradiance from RedEdge-MX is also lower than RAMSES by 1~20%. The correction coefficients for RedEdge-MX alculated through the 1-st and the 3-rd order regression analysis were presented as a result of the study.

• The Journal of the Korean dental association
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• v.15 no.5
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• pp.359-364
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• 1977

Orthognathic surgery, ie, the surgical correction of congenital and acquaired anormalities of the jaws, is currently a field of vigorous activity among oral surgeons. Surgical correction of maxillofacial deformities benefits the patient both psychologically and functionally. Facial mutilation may precipitate adverse psychologic effects. Function is frequently impaired by malrelation of the jaws. In addition, speech, specifically articulation, is often handicapped in patient with severe jaw deformities. Therefore, in dealing with these patient, above mentioned problem should be considered deliberately. In this regard, the authors have treated 2 cases of mandible defect caused by gunshot and explosives with iliac bone graft. In both cases, the patient had Tantalum plate on defect area. But it became lose and gave functional disturbances. So, the authors have removed Tantalum plate and performed bone transplantation with autogenous soild iliac bone graft on that area with good results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.4
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• pp.241-248
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• 2017

GCPs (Ground Control Points) are needed to correct the DEM (Digital Elevation Model) produced from high-resolution satellite images and the RPC (Rational Polynomial Coefficient). It is difficult to acquire the GCPs through field surveys such as GPS surveys and to read the image coordinates corresponding to the GCPs. In addition, GCPs cannot cover the entire image of the test site, and the RPC correction results may be influenced by the arrangement and distribution of the GCPs in the image. Therefore, a new method for the RPC correction is needed. In this study, an LHD (Least-squares Height Difference) DEM matching method was applied using previous DEMs: SRTM DEM, digital map DEM, and corrected IKONOS DEM. This was carried out to correct the DEM produced from KOMPSAT-3 satellite images and the provided RPC without GCPs. The IKONOS DEM had the highest accuracy, and the height accuracy was about ${\pm}3m$ RMSE in a mountainous area and about ${\pm}2m$ RMSE in an area with only low heights.