• Journal of Conservation Science
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• v.28 no.1
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• pp.87-94
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• 2012

This study was focused on digital restoration and surface depth modeling applying the three-dimensional laser scanning system of the Haeundae Stone Inscription. Firstly, the three-dimensional digital restoration carried out acquiring of point cloud using wide range and precision scanner, thereafter registering, merging, filtering, polygon mesh and surveyed map drawing. In particular, stroke of letters, inscribed depth and definition appearing the precision scanning polygon was outstanding compared with ones of the wide range polygon. The surface depth modeling completed through separation from polygon, establishment of datum axis, selection of datum point, contour mapping and polygon merging. Also, relative inscribed depth (5~17mm) and outline by the depth modeling was well-defined compared with photograph and polygon image of the inscription stone. The digital restoration technology merging wide range and precision scanning restored the total and detailed shape of the Stone Inscription quickly and accurately. In addition, the surface depth modeling visibly showed unclear parts from naked eye and photograph. In the future, various deteriorations and surrounding environment change of the Stone Inscription will be numerically analyze by periodic monitoring.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.191-196
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• 2019

The development of open-pit mines leads to large-area topographical changes in highland forests and can lead to severe deterioration of forests, requiring continuous monitoring. The drone photogrammetry is performed at a lower altitude than the existing manned aerial photogrammetry, and thus has a relatively high accuracy. The purpose of this study is to construct spatial information of large open pit mine using drone photogrammetry and to evaluate the accuracy and utilization of the results. The accuracy of the drone photogrammetric results was 0.018 ~ 0.063m in the horizontal direction and 0.027m ~ 0.088m in the vertical direction. These results satisfy the permissible accuracy of 1: 1,000 digital topographic map and it can be used for open mine monitoring. The geospatial information of the open pit mine can be used in various ways, and it can be used to monitor the quantitative change of a specific area for time series change through data management by periodic data acquisition. If drone photogrammetry is applied to open-pit mine monitoring in the future, work time and cost can be greatly reduced compared to the conventional GNSS or total station method, and the work efficiency can be greatly improved because more visible data can be generated.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.53-60
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• 2002

Motion of lung tumors from respiration has been reported in the literature to be as large as of 1-2 cm. This motion requires an additional margin between the Clinical Target Volume (CTV) and the Planning Target Volume (PTV). While such a margin is necessary, it may not be sufficient to ensure proper delivery of Intensity Modulated Radiotherapy (IMRT) to the CTV during the simultaneous movement of the DMLC. Gated treatment has been proposed to improve normal tissues sparing as well as to ensure accurate dose coverage of the tumor volume. The following questions have not been addressed in the literature: a) what is the dose error to a target volume without gated IMRT treatment\ulcorner b) what is an acceptable gating window for such treatment. In this study, we address these questions by proposing a novel technique for calculating the 3D dose error that would result if a lung IMRT plan were delivered without gating. The method is also generalized for gated treatment with an arbitrary triggering window. IMRT plans for three patients with lung tumor were studied. The treatment plans were generated with HELIOS for delivery with 6 MV on a CL2100 Varian linear accelerator with a 26 pair MLC. A CTV to PTV margin of 1 cm was used. An IMRT planning system searches for an optimized fluence map ${\Phi}$ (x,y) for each port, which is then converted into a dynamic MLC file (DMLC). The DMLC file contains information about MLC subfield shapes and the fractional Monitor Units (MUs) to be delivered for each subfield. With a lung tumor, a CTV that executes a quasi periodic motion z(t) does not receive ${\Phi}$ (x,y), but rather an Effective Incident Fluence EIF(x,y). We numerically evaluate the EIF(x,y) from a given DMLC file by a coordinate transformation to the Target's Eye View (TEV). In the TEV coordinate system, the CTV itself is stationary, and the MLC is seen to execute a motion -z(t) that is superimposed on the DMLC motion. The resulting EIF(x,y)is inputted back into the dose calculation engine to estimate the 3D dose to a moving CTV. In this study, we model respiratory motion as a sinusoidal function with an amplitude of 10 mm in the superior-inferior direction, a period of 5 seconds, and an initial phase of zero.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.525-538
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• 2019

The purpose of this study was to analyze the habitat status and species diversity of benthic diatoms and estimate the applicability of TDI (Trophic Diatom Index) to obtain the basic data for the identification and management of created wetlands in the Nakdong River. We observed a total of 38 families and 173 species of benthic diatom during the survey period, and spring and autumn showed a similar number of species of 156 and 154, respectively. The result of the SOM (Self-Organizing Map) analysis showed that the distribution of benthic diatom was sensitive to environmental factors such as nutrient concentration and rainfall in each wetland. The cluster 1 was characterized by the survey sites of autumn mostly and consisted of points of high TDI, although the nutrients such as total phosphorus and total nitrogen were low, and the species number and abundance of diatoms were low. Conversely, cluster 4 was characterized by the survey sites of spring mostly and consisted of points of low TDI, even though total nitrogen was high. Considering that most of the created wetlands had the reduced inflow and outflow, the increased flow rate in the summer lowers nutrient values in autumn, and the species number and abundance of benthic diatom decreases due to the increase of turbidity, which reduces the light penetrations to the substrates. On the contrary, the TDI value is low in spring because the low water level causes insufficient substrate surface to the benthic diatoms, and it is too early for the establishment and development of saprophilous species. Although various studies have used TDI as an indicator for evaluating the habitat environment and water quality, it is not a good evaluation indicator in this study since the nutrient concentration in the wetlands mostly high as they have a low flow rate and are close to the stagnant area. Nevertheless, additional periodic surveys that comprehensively reflect the fact that the summer rainfall and inflow/outflow regulating function might affect the species diversity and distribution of benthic diatoms are necessary.