• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.332-335
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• 2008

Newly developing SAR (Synthetic Aperture Radar) sensors commonly include high resolution X-band those data are expected to contribute various applications. Recent few studies are presenting potential of X-band SAR data in forest related application. This study tried to investigate the relationship between forest stand parameters and multi-band SAR normalized backscattering. Multi-band SAR data was radiometric corrected to compare signal from different forest stand condition. Then correlation coefficients were estimated between attribute of forest stand map and normalized backscattering coefficients. Although overall correlation coefficients are not high, only X-band shows strong relationship with DBH class than other bands. The signal of C- and L-band is composed of a large number of discrete tree components such as leaves, stems, even background soil. In forest, strength of radar backscattering is affected by complex parameters. Further study might be considered more various forest stand parameters such as canopy density, stand height, volume, and biomass.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.251-259
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• 2010

It is presented in this study a new efficient intelligent machining strategy, which can be used to remove the uncut volume at the boundary region of curved surfaces caused by cutter interference. The geometric form definitions and recognition of topological features of the surface triangulation mesh are used to generate cutter paths along successive and interconnected steepest pathways, that minimize the cusp height left after flat end milling. In order to machine the uncut volume gradually, the z-map cutter centers are adjusted to avoid cutter interference for the 6 kinds of avoidance types. And then, the generative subsequent paths are sequenced to determine the second step cutter paths for the next uncut volume. For the 2 kinds of test models with convex and concave surface region, the implemented software algorithm is evaluated by investigating the residual swelling of uncut volume for each machining step.

• Water for future
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• v.6 no.1
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• pp.5-12
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• 1973

A simple regression formula for estimating the lake evaporation rate from the copper-plated pan (diameter 20cm, height 10cm) is derived. A comparison with other formulae indicates that the formula is more accurate than others. An annual map of man evaporation in Korean peninsula has been prepared using the relation. It demonstrates the areal average distribution of mean annual evaporation from a free water surface with no heat storage effect and avected energy owing to differences in the temperature of in-and outflow. The mean annual ratio of the lake to the copper-plated pan evaporation is found to be 0.64. The ratio varies with local conditions from 0.62 to 0.66, and hence it can be considered fairly uniform. However the seasonal variation of the ratio appears to be rather significant. It changes from the lowest of 0.61 to the highest of 0.75.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1262-1266
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• 2004

The current combining of computer and geographic information technology. The result of such research oil determinate objective factors of hydrologic-topographical parameters through joining hydrology and GIS(Geographic Information System). In this study, we wish to offer the base data to determinate hydrologic-topographical parameters request of runoff model analysis in this basin. First, we computed the CN(curve number) by using GIS, and then classify the digital map of soil group and landuse on the Sulma river basin. Second, we used Avenue Script to calculate the height of efficient GIS work before using the Clark model to work out flood runoff flow.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.105-110
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• 2002

For the accuracy assessment of DTM obtained by Airborne Laser Mapping Systems (ALMS), we selected 500 m spaced test points and analyze the accuracy of the DTM by various methods including GPS survey. To estimate the height at the point in between the test points of the DTM we produced a TIN, and to analyze the accuracy we use a GPS coverage map overlaid with the TIN. Compared with the existing method, DTM by ALMS is shown to be relatively accurate, and therefore, ALMS is applicable to 1/5000 digital terrain mapping.

• Journal of the Korean Professional Engineers Association
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• v.45 no.1
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• pp.45-48
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• 2012

The 2011 Japan Tsunami caused tremendous damage to coastal areas. Because of their drastic propagation speed and large run-up height, nearshore tsunami can cause catastrophic damages on coastal communities within a short time. It is necessary to establish the tsunami hazard mitigation to reduce human injury housing damage. The construction of Tsunami warning system and production of hazard map are needed for minimizing damage by tsunami.

• Korean Journal of Geomatics
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• v.2 no.1
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• pp.31-35
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• 2002

This paper describes an experiment for three-dimensional positioning for a pair of KOMPSAT stereostrips using the ancillary data and a single ground control point. The photogrammetric model for three-dimensional positioning was performed as follows: first, initialization of orbital and attitude parameters derived from ancillary data; second, adjustment of orbital and attitude parameters for the satellite to minimize the ground position error with respect to a GCP using the collinearity condition; third, determination of actual satellite position; and lastly, space intersection. This model was tested for a pair of stereo strips with 0.6 base-to-height ratio and GCPs identified from a 1:5,000 scale digital map. As the result, the satellite position of offset was corrected by only one GCP and the accuracy for the geometric modeling showed 38.89m RMSE.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.02a
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• pp.64-72
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• 2004

Correction of shadow effects is critical step for image interpretation and feature extraction from aerial imagery. In this paper, an efficient algorithm to correct shadow effects from aerial color imagery is presented. The following steps have been performed to remove the shadow effect. First, the shadow regions are precisely located using the solar position and the height of ground objects derived from LIDAR (Light Detection and Ranging) data. Subsequently, segmentation of context regions is implemented for accurate correction with existing digital map. Next step, to calculate correction factor the comparison between the context region and the same non-shadowed context region is made. Finally, corrected image is generated by correcting the shadow effect. The result presented here helps to accurately extract and interpret geo-spatial information from aerial color imagery

• Journal of Plant Biology
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• v.27 no.2
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• pp.51-60
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• 1984

Jisimdo is an island where evergreen broadleaved forests are well preserved. Soil environments and forest structures of Jisimdo were investigated, and an actual vegetation map and profile diagrams were drawn out. The natural vegetation of Jisimdo was divided into two stand units, one was evergreen broadleaved forest and the other was Pinus thunbergii forest. 26 species were identified as evergreen broadoeaved trees, and among them, Camellia japonica was the dominont of the tree layer of evergreen broadleaved forest. Profile diagram shows that Camellia japonica, with average height of 7∼8m, formed lower tree layer, and laurels like Cinnamomum japonicum, Machilus thunbergii, and Neolitsea sericea formed upper tree layer. In Pinus thunbergii forest, plants of shrub and herb layers were abundant because of much light penetrated into the forest floor, and these layers were largely composed of evergreen broadleaved trees. This fact shows the possibility of succession from Pinus thunbergii forest into evergreen broadleaved forest. Jisimdo is geographically adjacent to Jangseungpo and Okpo, and this increases the economic value of Jisimdo as a place of public resort. It will be necessary from being destroyed by land development and human interferences.

• Journal of the Korean GEO-environmental Society
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• v.15 no.3
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• pp.65-74
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• 2014

Borehole investigation which is mainly used to figure out geotechnical characterizations at construction work has the benefit that it provides a clear and convincing geotechnical information. But it has limitations to get the overall information of the construction site because it is performed at point location. In contrast, geophysical measurements like seismic survey has the advantage that the geological stratum information of a large area can be characterized in a continuous cross-section but the result from geophysics survey has wide range of values and is not suitable to determine the geotechnical design values directly. Therefore it is essential to combine borehole data and geophysics data complementally. Accordingly, in this study, a three-dimensional spatial interpolation of the cross-sectional distribution of seismic refraction was performed using digitizing and geostatistical method (krigring). In the process, digital map were used to increase the trustworthiness of method. Using this map, errors of ground height which are broken out in measurement from boring investigation and geophysical measurements can be revised. After that, average seismic velocity are derived by comparing borehole data with geophysical speed distribution data of each soil layer. During this process, outlier analysis is adapted. On the basis of the average seismic velocity, integrated analysis techniques to determine the three-dimensional geological stratum information is established. Finally, this analysis system is applied to dam construction field.