• Korean Journal of Remote Sensing
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• v.23 no.1
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• pp.7-14
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• 2007

Atmospheric correction is one of critical procedures to extract quantitative information related to biophysical variables from hyperspectral imagery. Most atmospheric correction algorithms developed for hyperspectral data have been based upon atmospheric radiative transfer (RT) codes, such as MODTRAN. Because of the difficulty in acquisition of atmospheric data at the time of image capture, the complexity of RT model, and large volume of hyperspectral data, atmospheric correction can be very difficult and time-consuming processing. In this study, we attempted to develop an efficient method for the atmospheric correction of EO-1 Hyperion data. This method uses the pre-calculated look-up-table (LUT) for fast and simple processing. The pre-calculated LUT was generated by successive running of MODTRAN model with several input parameters related to solar and sensor geometry, radiometric specification of sensor, and atmospheric condition. Atmospheric water vapour contents image was generated directly from a few absorption bands of Hyperion data themselves and used one of input parameters. This new atmospheric correction method was tested on the Hyperion data acquired on June 3, 2001 over Seoul area. Reflectance spectra of several known targets corresponded with the typical pattern of spectral reflectance on the atmospherically corrected Hyperion image, although further improvement to reduce sensor noise is necessary.

• Fire Science and Engineering
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• v.25 no.1
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• pp.42-49
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• 2011

In the high temperature situation like in a fire, the high strength of concrete (HSC) has extreme danger named explosive spalling. It is assumed that the major cause of explosive spalling is water vapour pressure inside concrete. This paper examines the effect of the compressive strength and the moisture content on the initial occurrence of explosive spalling. For the effective experiment of the initial explosive spalling, the curve of ISO834 temperature profile is applied on the basis of 15 minute and 30 minute. As a result, the more increase the compressive strength and the moisture content, the more increase the occurrence and phenomenon of explosive spalling. This paper analyzes the territory of explosive spalling depending the compressive strength and the moisture content. The explosive spalling is not examined in the case of the compressive strength 50~100 MPa and the moisture content below 3% and the compressive strength over 100 MPa and the moisture content below 1%. Also, due to the HSC, which makes it more difficult to transport vapour and moisture, very high vapour-pressure may occur close to the surface, there is a greater risk that HSC spalls compared with normal strength concrete (NSC).