• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.973-974
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• 2009

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.11
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• pp.1153-1163
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• 2014

An efficient 3D SLAM (Simultaneous Localization and Map Building) method is developed for urban building environments using a tilted 2D LRF (Laser Range Finder), in which a 3D map is composed of perpendicular/horizontal planar polygons. While the mobile robot is moving, from the LRF scan distance data in each scan period, line segments on the scan plane are successively extracted. We propose an "expected line segment" concept for matching: to add each of these scan line segments to the most suitable line segment group for each perpendicular/horizontal planar polygon in the 3D map. After performing 2D localization to determine the pose of the mobile robot, we construct updated perpendicular/horizontal infinite planes and then determine their boundaries to obtain the perpendicular/horizontal planar polygons which constitute our 3D map. Finally, the proposed SLAM algorithm is validated via extensive simulations and experiments.

• The Journal of Korean Academy of Sensory Integration
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• v.16 no.1
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• pp.35-44
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• 2018

Objective : This study aimed to perform a translation, backward translation, item modification, and test of content validity for Korean version of Miller Assessment for Preschoolers (MAP). Methods : Professors in department of occupational therapy, translators, or occupational therapists participated in the processes of translation, comparison and synthesis I, backward translation, comparison and synthesis II, test of understanding, and modify of items. Content Validity Indices (CVI) was calculated for data analysis by using Microsoft Office Excel. Results : Results of comparison between the original MAP and Korean MAP in professor panels were mean $3.66{\pm}0.40$, item-level CVI (I-CVI) 0.94, and overal scale CVI (S-CVI) 0.83. In agreement, result of comparison between of the original MAP and backward translated MAP (version English) was mean 3.14. The erroneous content was omission 13 times, the addition 3 times, the substitution 6 times, erroneous terms 11 times, and reordering 6 times. Average of understanding test in the therapist panels was $3.66{\pm}0.27$. The agreements were I-CVI 0.93 and S-CVI 0.58. Conclusion : Using assessment tools that developed in another country is important to do test of content validity and systematic translation process in Korea. For developing Korean version of MAP, validity and reliability studies need to be followed in near future.

• Bulletin of the Korean Mathematical Society
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• v.47 no.4
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• pp.859-881
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• 2010

The helicoidal surface is a generalization of rotation surface in a Minkowski space. We study helicoidal surfaces in a Minkowski 3-space in terms of their Gauss map and provide some examples of new classes of helicoidal surfaces with constant mean curvature in a Minkowski 3-space.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.2
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• pp.77-86
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• 2014

As raster-based high quality and resolution spatial information has appeared, 1/1,000 digital map lost either its recognition or uses because of insufficient new modified and updated information. Therefore, this study analyzed the linkage between three-dimensional spatial information and 1/1,000 digital map, and also suggested a modification plan of 1/1,000 digital map, made by three-dimensional spatial information. In fact, some area of Incheon and Busan were presented with the modification plan of 1/1,000 digital map as three-dimensional trial models. These trials reflected possibilities of modification by qualitative and quantitative analysis of 1/1,000 digital map, using three-dimensional object model.

• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.284-290
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• 2020

In this paper, we propose a method to generate and optimize the height map that is suitable to render a soap bubble. The height map represents the flow speed of soap bubbles. To this end, we have analyzed the flow of the soap bubble surface through experiment, derived the moving speed value for each section. Some image filters have been used for optimization that reflects the parameters of the derived height map. In addition, in order to verify the results of the study, actual data measuring the surface flow speed of soap bubbles, the speed of the initial height map, and the optimized height map speed have been compared and tested. Through this study, we reach the issue that it is possible to express the variable flow speed of soap bubbles with the optimized height map, and it will help to express various fluids.

• Journal of the Korea Society of Computer and Information
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• v.20 no.10
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• pp.39-44
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• 2015

In this paper, we analyze the immersion effects according to the level of map in adventure game. Computer games are actively enjoyed by many people around the world. Game players have frequently experienced the immersion which is an important aspect to be attained from games. However, it is not clear what immersion is and what kinds of factors influence to immersion. Nonetheless, in recent many researches, the elements of humanities and fun were found as factors of immersion in various digital contents such as game, virtual reality, cinema and etc. Therefore, today's games are developed on the basis of the humanities and fun theory that many researchers have been studied for a long time. In games, the balance of the level of map is related with immersion. Hence, it is important to know how the map patterns of game affect immersion of players. In this paper, we developed a 3D survival adventure game named by "1 Hour" using Unity3D in order to simulate how map patterns affect immersion of players. We also analyzed the relationship between the level of map and immersion using the game.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.3
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• pp.253-259
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• 2014

This study proposes a map-based control method to improve a vehicle's lateral stability, and the performance of the proposed method is compared with that of the conventional model-referenced control method. Model-referenced control uses the sliding mode method to determine the compensated yaw moment; in contrast, the proposed map-based control uses the compensated yaw moment map acquired by vehicle stability analysis. The vehicle stability region is calculated by a topological method based on the trajectory reversal method. The performances of model-referenced control and map-based control are compared under various road conditions and driving inputs. Model-referenced control uses a control input to satisfy the linear reference model, and it generates unnecessary tire lateral forces that may lead to worse performance than an uncontrolled vehicle with step steering input on a road with low friction coefficient. The simulation results show that map-based control provides better stability than model-referenced control.

• Journal of the Korean Mathematical Society
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• v.46 no.1
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• pp.215-223
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• 2009

The helicoidal surfaces with pointwise 1-type or harmonic gauss map in Euclidean 3-space are studied. The notion of pointwise 1-type Gauss map is a generalization of usual sense of 1-type Gauss map. In particular, we prove that an ordinary helicoid is the only genuine helicoidal surface of polynomial kind with pointwise 1-type Gauss map of the first kind and a right cone is the only rational helicoidal surface with pointwise 1-type Gauss map of the second kind. Also, we give a characterization of rational helicoidal surface with harmonic or pointwise 1-type Gauss map.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.423-427
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• 2010

To develope SOC(social overhead capita) which constructs the railroad, highway etc., the geo-technical foundation have to be well understood for the safety works. In this paper, we selected Moonkyung area for the study area, which has various geological units and geological structure including the big thrust and fold. By this reason one of the geo-technical information is the engineering geology map. To make the map, lithology and soil distribution with drilling data are important elements. Three dimensional geo-infomation is established by fence diagram which is several geological cross sections and/or computer software 3D Geomodeller, EarthVision, GSI3D, Gocad.