• Journal of Environmental Science International
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• v.22 no.9
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• pp.1079-1088
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• 2013

The objective of this paper is compare to landuse type for calculating peak flood and soil loss in rapidly expansion urban area. This study compares two landuse maps, including numerical landuse map and aerial photograph landuse map, for calculating the ratio of urban and agriculural area, curve number, time of concentration, peak flood discharge, and soil loss. It is found that flood discharge calculated using aerial photograph landuse map are larger than that calculated using numerical landuse map, and soil loss calculated using aerial photograph landuse map are smaller than that calculated using numerical landuse map. Results also indicate that landuse chage in rapidly expansion urban area significantly influences flood discharge and soil loss.

• The Journal of Korea Robotics Society
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• v.13 no.2
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• pp.79-85
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• 2018

This study focuses on autonomous exploration based on map expansion for an underwater robot equipped with acoustic sonars. Map expansion is applicable to large-area mapping, but it may affect localization accuracy. Thus, as the key contribution of this paper, we propose a method for underwater autonomous exploration wherein the robot determines the trade-off between map expansion ratio and position accuracy, selects which of the two has higher priority, and then moves to a mission step. An occupancy grid map is synthesized by utilizing the measurements of an acoustic range sonar that determines the probability of occupancy. This information is then used to determine a path to the frontier, which becomes the new search point. During area searching and map building, the robot revisits artificial landmarks to improve its position accuracy as based on imaging sonar-based recognition and EKF-SLAM if the position accuracy is above the predetermined threshold. Additionally, real-time experiments were conducted by using an underwater robot, yShark, to validate the proposed method, and the analysis of the results is discussed herein.

• Journal of Broadcast Engineering
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• v.12 no.2
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• pp.112-119
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• 2007

Reversible data embedding theory has marked a new epoch for data hiding and information security. Being reversible, the original data and the embedded data as well should be completely restored. Difference expansion transform is a remarkable breakthrough in reversible data hiding scheme. The difference expansion method achieves high embedding capacity and keeps the distortion low. This paper shows that the difference expansion method with simplified location map, and new expandability and changeability can achieve more embedding capacity while keeping the distortion almost the same as the original expansion method.

• Journal of the Korean Mathematical Society
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• v.38 no.3
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• pp.669-681
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• 2001

This paper introduces the notions of essential and inessential map for countably $textsc{k}$-set contractive maps. These ideas enable us to establish a Krasnoselskii-Petryshyn compression and expansion theorem in a cone for countably $textsc{k}$-set contractive maps.

• Journal of the Chungcheong Mathematical Society
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• v.17 no.2
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• pp.125-136
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• 2004

This paper introduces the notion of semi-compatible self-maps in 2-metric spaces and establishes a fixed point theorem for four self-maps, satisfying an implicit relation through semi-compatibility of a pair of self-maps. This results in another fixed point theorem for four expansion maps which generalizes and improves many results of Kang et. al. [5] with an application.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.6
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• pp.125-135
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• 2020

The uncontrolled urban expansion causes various social, economic problems and natural/environmental problems. Therefore, it is necessary to forecast urban expansion by identifying various factors related to urban expansion. This study aims to forecast it using a decision tree that is widely used in various areas. The study used geographic data such as the area of use, geographical data like elevation and slope, the environmental conservation value assessment map, and population density data for 2006 and 2018. It extracted the new urban expansion areas by comparing the residential, industrial, and commercial zones of the zoning in 2006 and 2018 and derived a decision tree using the 2006 data as independent variables. It is intended to forecast urban expansion in 2030 by applying the data for 2018 to the derived decision tree. The analysis result confirmed that the distance from the green area, the elevation, the grade of the environmental conservation value assessment map, and the distance from the industrial area were important factors in forecasting the urban area expansion. The AUC of 0.95051 showed excellent explanatory power in the ROC analysis performed to verify the accuracy. However, the forecast of the urban area expansion for 2018 using the decision tree was 15,459.98㎢, which was significantly different from the actual urban area of 4,144.93㎢ for 2018. Since many regions use decision tree to forecast urban expansion, they can be useful for identifying which factors affect urban expansion, although they are not suitable for forecasting the expansion of urban region in detail. Identifying such important factors for urban expansion is expected to provide information that can be used in future land, urban, and environmental planning.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.49-54
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• 2003

As of date, the cadastral information which is the utility to be computerized have not been identical with local autonomous entities and relational groups each other and updated real-time, therefore the relation group or the academic circles carried out in many researches on a cadastral map matching, but the cadastral maps have not been even occurred the expansion and contraction so that the theory arrangement doesn't seem simple as to a cadastral map matching. As being take such reality into consideration, We have to be based on $\boxDr$construction ministry of the rules for continuous map$\boxUl$ for a continuous cadastral map with using PBLIS data; so the operators use Autodesk Map 5 which added applications and match the neat line by the identical scale, the different scale, the district boundary and the origin according to the judgement myself We have the purpose to minimize the problem as analyzing the accuracy between the parcel coordinates If the matched map and ones of moved map.

• Journal of the Chungcheong Mathematical Society
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• v.11 no.1
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• pp.73-85
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• 1998

This paper deals with the topological stability of continuous maps. First, the notion of local expansion is given and we show that local expansions of compact metric spaces have the shadowing property. Also, we prove that if a continuous surjective map f is a local homeomorphism and local expansion, then f is topologically stable in the class of continuous surjective maps. Finally, we find homeomorphisms which are not topologically stable.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.997-1002
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• 2009

The local loosening of ballast supporting railway tract cause a differential vertical tract settlement. In the bridge, the temperature change make bridge deck to contract and expand, and this movement cause local loosening of ballast on the bridge expansion joint. Therefore, the evaluation of the status of ballast on the bridge expansion joint is important for the track maintenance of the high-speed railway. In this paper, hwaw method was applied to evaluate the status of ballast on the bridge expansion joint. HWAW method is non-destructive test to evaluate 2-D shear wave velocity map along the railway. Shear wave velocity is directly related with status of ballast. In this research, hwaw method was applied two different types of bridges and determine the degree and the range of the ballast loosening caused by movement of the bridge expansion joint.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.985-987
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• 2011

This paper includes a development of a starting time prediction model for a derivative engine. For this derivative engine design, a new map expansion method, Modified Pump Scaling Law(MPS), has been applied and expand the maps to sub-idle range. From loss characteristics of the reference engine, loss models for the derivative engine have been developed considering different pressure, temperature, and engine configurations. Starting time predictions of the derivative engine shows preferable results comparing test results.