• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.129-132
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• 2002

The practical virtual compensator, which uses a dynamic multi-leaf collimator (dMLC) and three-dimensional radiation therapy planning (3D RTP) system, was designed. And the feasibility study of the virtual compensator was done to verify that the virtual compensator acts a role as the replacement of the physical compensator. Design procedure consists of three steps. The first step is to generate the isodose distributions from the 3D RTP system (Render Plan, Elekta). Then isodose line pattern was used as the compensator pattern. Pre-determined compensating ratio was applied to generate the fluence map for the compensator design. The second step is to generate the leaf sequence file with Ma's algorithm in the respect of optimum MU-efficiency. All the procedure was done with home-made software. The last step is the QA procedure which performs the comparison of the dose distributions which are produced from the irradiation with the virtual compensator and from the calculation by 3D RTP. In this study, a phantom was fabricated for the verification of properness of the designed compensator. It is consisted of the styrofoam part which mimics irregular shaped contour or the missing tissues and the mini water phantom. Inhomogeneous dose distribution due to the styrofoam missing tissue could be calculated with the RTP system. The film dosimetry in the phantom with and without the compensator showed significant improvement of the dose distributions. The virtual compensator designed in this study was proved to be a replacement of the physical compensator in the practical point of view.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.231-243
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• 2016

This study presents the applicability of two-dimensional (2D) flood inundation model by applying to real irrigation reservoir failure with limited available data. The study area is Sandae Reservoir placed in Gyeongju and downstream area of it and the reservoir was failured by piping in 2013. The breach hydrograph was estimated from one-dimensional (1D) hydrodynamic model and the discharge was employed for upstream boundary of 2D flood inundation model. Topography of study area was generated by integrating digital contour map and satellite data, and Cartesian grids with 3m resolution to consider geometry of building, road and public stadium were used for 2D flood inundation analysis. The model validation was carried out by comparing predictions with field survey data including reservoir breach outflow, flood extent, flood height and arrival time, and identifying rational ranges with allowed error. In addition, the applicability of 2D model is examined using different simulation conditions involving grid size, building and roughness coefficient. This study is expected to contributed to analysis of irrigation reservoirs were at risk of a failure and setting up Emergency Action Plan (EAP) against irrigation reservoir failure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.274-280
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• 2017

The smart-car industry has emerged as the important variable that will decide the future industrial contour of the automotive industry, together with commercialization of electronic vehicles, connected cars, infotainment, telematics, and the autonomous/self-driving car. This study analyzes the strategic position of platform companies and car manufacturers that would determine the future of the smart-car market. The findings of this study show that despite the entry barriers in industrial factors, such as economies of scale, the industrial infrastructure, and global production networks, and technical factors like exclusive head-sector information, car manufacturers may be deprived of their industrial leadership by platform companies with map and user data, big data capabilities, and user interface experience if they lag behind ICT innovation. This insight is based on the emerging importance of software and platforms, and the simplification of car structures, proven by the successful commercialization of electronic vehicles. This study complements existing studies mainly focused on technical aspects of the smart-car industry by examining the strategic dimensions of platform companies and their approach to the future smart-car market by comparing them with existing car manufacturing multinationals.

• Korean journal of food and cookery science
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• v.28 no.3
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• pp.275-283
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• 2012

This study was conducted to monitor the quality characteristics of Lespedeza cuneata ethanolic extracts, by a response surface methodology. The independent variables were the extraction temperature ($35{\sim}95^{\circ}C}$), extraction time (2~10 hr), and ethanol concentration (10~90%). The coefficients of the determinations (R2) were 0.8562 (p<0.1), 0.9787 (p<0.01), and 0.8344 (p<0.1) in total polyphenol, total flavonoid, and electron donating ability, respectively. The electron donating ability and nitrite scavenging effect were improved with an increase of ethanol concentration, rather than the extraction temperature. ORAC (Oxygen Radical Absorbance Capacity) with extraction conditions was 1,636.47~2,696.99 ${\mu}moles$ TE/g, and was increased with the increase of extraction temperature and 40~60% of ethanol concentration. Estimated conditions for the maximized extraction including the yield, total polyphenol, electron donating ability, nitrite scavenging effect, and ORAC, were $60{\sim}68^{\circ}C$ in extraction temperature, 6~7 hr in extraction time, and 38~60% in ethanol concentration.

• Journal of Technology Innovation
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• v.21 no.2
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• pp.25-56
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• 2013

As science and technology are emphasized as national competitiveness, major nations designate new growth engine industry and establish the effective investment and the development strategy to enhance industrial development and competitiveness through science and technology. New industrial sectors such as Biotechnology and renewable energy have been spot lighted as major new growth engines and this competitive situation is getting fiercer. Universities and research institutions in each country selected and announced the future promising technological field which will produce ripple effect in the future on a regular basis. In Korea, various research institutions continue to select and announce the promising technological fields. In this study, we would like to study the method to derive the promising technological field in the field of biotechnology spotlighted as a new growth engine by utilizing patent information. We would like to derive the major technological field by collecting domestic and international patents in the field of biotechnology using IPC code based technological classification and identifying bio technological trends utilizing text mining method for analysis of technological development trends with patents. Patent contour of US and Korea is compared and analyzed through analysis of text mining to derive the general technological development field in the field of biotechnology. After that, we would like to investigate research theme of promising biotechnology focused technological development through details on technological trends through in-depth analysis about technological field which draws interest more and more in Korea and other countries.

• Korean Journal of Ecology and Environment
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• v.33 no.1 s.89
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• pp.31-37
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• 2000

For the purpose of surveying the physicochemical composition of sediment collected from Kwangyang Bay, the percentage of water loss, COD, $H_2S$, grain size and 10 heavy metals were studied at 17 sites. During the surveying period, the changes of the percentage of water loss were appeared $35.5\;{\sim}\;53.8%$. COD and $H_2S$ were showed $3.8\l{\sim}\;12.9\;mg/g$, and $0.1\;{\sim}11.4\;{\mu}g/g$, respectively, In composition of grain size on the sediment, percentages of grain sizes under $74\;{\mu}m$ were varied from 40.5% to 86.7% and above $74\;{\mu}m$ were varied from 11.5% to 43.0%. From the spatial distribution of heavy metal using contour map, we can suppose some heavy metal discharges which affect sediment of Kwangyang Bay, It was estimated that Shinpung creek, Ssang-bong creek, and draining area of sewange treatment plant were the main discharge among the heavy metal output sources. By comparison between present study and heavy metal guideline of nonpolluted sea sediment that is provided by EPA, US, it was showed that the contents of Pb and Hg were acceptable but contents of Mn, Zn, Cu, Fe, As, and Cr were higher than those of EPA guideline.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.4
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• pp.234-246
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• 2007

The role of macropore in the hydrological processes is important at the hillslope scale. Developments and distribution of macropores have not been investigated in conjunction with the characteristics of the hillslope such as topography, soil property, and soil moisture. In this study, macropore properties, such as macropore flow and saturation hydraulic conductivity were measured at a hillslope located in Gwangneung Research Forest, Pochun-gun, Gyeonggi-do, South Korea. An intensive field survey provided a refined Digital Elevation Model (DEM) for surface and subsurface topography. Spatial distributions of upslope area and topographic index were obtained through the digital terrain analysis. The total number of monitoring points was 22, and the selected points were distributed along the transect of the digital contour map. Vertical fluxes through macropores were measured using a tension infiltrometer at the depth of 0.1 m from the surface. Spatial and temporal distributions of soil moisture were obtained using an on-line measurement system, TRASE, installed in the study area. Soil moisture for the aforementioned points was measured at 0.1 and 0.3m depths below the surface. The results from tension infiltrometer experiments present that the macropore flows ranged between 21 and 94%, and the measured macroporosities varied from 1.4 to 47%. Macropore flows and macroporosities tended to increase as the measurement location moved to downslope. The ability for water conduction through macropores becomes increasingly developed as the location approaches the outlet of the hillslope.

• Food Science and Preservation
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• v.18 no.5
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• pp.755-763
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• 2011

This study was conducted to monitor the quality characteristics Citrus unshiu ethanolic extracts by a response surface methodology. In extraction conditions based on the central composite design with variations in ethanol concentration (0~100%), extraction temperature($35\sim95^{\circ}C$), and ratio of solvent to sample(20 mL/g). The maximum value of yield was 36.31% at $93.18^{\circ}C$, 67.13% of ethanol concentration. The extraction yield and total polyphenol content were improved with the increase of ethanol concentration than extraction temperature. Total flavonoid content was improved with the increase of extraction temperature than ethanol concentration. The coefficients of determinations($R^2$) were 0.8646(p<0.1) and 0.9153(p<0.05) in electron donating ability and hesperidin content, respectively. Estimated conditions for the maximized extraction including yield, total polyphenol content, total flavonoid content, electron donating ability, and hesperidin content were 55~73% in ethanol concentration, $89\sim95^{\circ}C$ in extraction temperature, and 20 mL/g in ratio of solvent to sample.

• Journal of Korea Water Resources Association
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• v.50 no.12
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• pp.877-887
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• 2017

The energy losses due to surcharged flow at four-way combining manhole, which is mainly installed in the downstream of urban sewer system, is the main cause of inundation in urban area. Surcharged four-way combining manholes form various flow configuration such as straight through, T-type, and four-way manholes depending on variation of inflow discharge in inlet pipes. Therefore, it is necessary to analyze change of energy loss and estimate head loss coefficients at surcharged four-way combining manhole with variation of inflow discharge ratio. The hydraulic experimental apparatus which can change inflow ratios were installed to analyze the flow characteristics at four-way combining manhole. In this study, to calculate the head loss coefficient according to change of the inflow discharge ratios at the surcharged four-way combining square manhole, the discharge conditions of 40 cases which the inflow ratios of each inlet pipe were changed by 10% interval was selected. The head loss coefficient at surcharged square manhole showed the lowest value of 0.40 at the straight manhole and the highest value of 1.58 at the $90^{\circ}$ junction manhole. In the combining manholes (T-type and four-way), the head loss coefficients were calculated more higher as the lateral flow rate was biased. The contour map of head loss coefficient range was constructed by using the estimated head loss coefficients and the empirical formula of head loss coefficients was derived to consider the variation of inflow discharge ratios at the surcharged square manhole. The empirical formula could be applied to the design and assessment of the urban drainage system.

• 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.