• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.548-551
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• 2007

Among components of digital topographic maps used officially in Korea, only contours have 3D values except buildings and trees that are demanded in landscape planning. This study presented a series of processes for 3Dreconstructing landscape features such as terrain, buildings and standing trees using LiDAR (Light Detection And Ranging) data and aerial digital photo graphs. The 3D reconstructing processes contain 1) building terrain model, 2) delineating outline of landscape features, 3) extracting height values, and 4) shaping and coloring landscape features using aerial photograph and 3-D virtual data base. LiDAR data and aerial photograph was taken in November 2006 for $50km^{2}$ area in Sorak National Park located in eastern part of Korea. The average scanning density of LiDAR pulse was 1.32 points per square meter, and the aerial photograph with RGB bands has $0.35m{\times}0.35m$ spatial resolution. Using reconstructed 3D landscape features, visibility with the growing trees with time and at different viewpoints was analyzed. Visible area from viewpoint could be effectively estimated considering 3D information of landscape features. This process could be applied for landscape planning like building scale with the consideration of surrounding landscape features.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.471-478
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• 2011

This UGV (Unmanned Ground Vehicle) is not only widely used in various practical applications but is also currently being researched in many disciplines. In particular, obstacle avoidance is considered one of the most important technologies in the navigation of an unmanned vehicle. In this paper, we introduce a simple algorithm for path planning in order to reach a destination while avoiding a polygonal-shaped static obstacle. To effectively avoid such an obstacle, a path planned near the obstacle is much shorter than a path planned far from the obstacle, on the condition that both paths guarantee that the robot will not collide with the obstacle. So, to generate a path near the obstacle, we have developed an algorithm that combines an edge detection method and a limit-cycle navigation method. The edge detection method, based on Hough Transform and IR sensors, finds an obstacle's edge, and the limit-cycle navigation method generates a path that is smooth enough to reach a detected obstacle's edge. And we proposed novel algorithm to solve local minima using the virtual wall in the local vision. Finally, we verify performances of the proposed algorithm through simulations and experiments.

• Journal of Auto-vehicle Safety Association
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• v.15 no.4
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• pp.16-22
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• 2023

This paper presents a proactive longitudinal motion planning algorithm for improving the safety of an automated bus. Since the field of view (FOV) of the autonomous vehicle was limited depending on onboard sensors' performance and surrounding environments, it was necessary to implement vehicle-to-vehicle (V2V) communication for overcoming the limitation. After a virtual V2V-equipped target was constructed considering information obtained from V2V communication, the reference motion of the ego vehicle was determined by considering the state of both the V2V-equipped target and the sensor-detected target. Model predictive control (MPC) was implemented to calculate the optimal motion considering the reference motion and the chance constraint, which was deduced from manual driving data. The improvement in driving safety was confirmed through vehicle tests along actual urban roads.

• Archives of design research
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• v.16 no.2
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• pp.255-270
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• 2003

The main goal of this study is to find the role of landmarks in route communication process and to explore the describability of landmarks, a linguistic factor of landmarks that was not noted frequently by previous wayfinding studies. Through analysis of landmarks in this study, the describability of landmarks was identified and this study hypothesized that the describability affects to the whole process of route communication. A virtual reality (VR) simulation test was conducted to examine the effect of the describability of landmarks in route communication. The independent variable was the describability of landmarks and landmarks. As dependent variables, the total time to find final destination and the number of errors were measured. Results showed that the describability of landmarks gives positive effect to the whole of route communication processes. Consequently, this study provides the solution of wayfinding problems in route communication and suggests the usage of landmarks as a prerequisite for planning spaces having the efficiency of wayfinding.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.3
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• pp.231-238
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• 2017

Using 3D based BIM(Building Information Modeling) enables a variety of construction simulations. The is no case to simulate BIM demonstration experiment on deeply immersed virtual reality environment in korea. This paper develops a multi screen based simulation system to enable 3D based immersed environment to diverse decision making and virtual construction simulation. In a developed simulation laboratory, we can carry out BIM drawing review, disaster evacuation simulation, constructability review on wild land and design urban planning using haptic device on 3-side space with 4K resolution . Also, It can review large amount of drawings without data conversion because of compatibility with BIM software.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.1 no.1
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• pp.55-64
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• 2003

In this study, the maintenance process by the servo manipulator has been developed for the parts of the equipment, which we unable to reach out by the Master-Slave Manipulator(MSM) in a hot cell. To do this, a virtual mock-up is implemented using the iか prototyping technology. Using this mock-up, the workspace of the manipulators in the hot cell and the operator's view through the wall-mounted lead glass have been analyzed. In addition, the path planning of the servo manipulator using the collision detection function of the virtual mock-up has been established. From these, the maintenance process for the parts of the equipment, which are located at the outside of the MSM's workspace using the servo manipulator has been proposed and verified through the graphic simulation. It is revealed that the proposed remote maintenance process of the equipment can effectively be used in the real hot cell operation. It is also believed that the implemented virtual mock-up of the hot cell can effectively be applied in analyzing the various hot cell operation and enhancing the reliability and safety in a hot cell remote handling for the spent fuel management.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.337-344
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• 2003

In this study, the maintenance process by the servo manipulator for the parts of the equipment that cannot be reached by MSM in the hot cell was developed. To do this, the virtual mock up is implemented using virtual prototyping technology. And, Using this mock-up, the workspace of the manipulators In the hot cell and the operator's view through the wall-mounted lead glass are analyzed. And the path planning of the servo manipulator using the collision detection of the virtual mockup is established. Also, the maintenance process for the parts of the equipment that are located out area of the MSM's workspace by the servo manipulator is proposed and verified through the graphic simulation. The proposed remote maintenance process of the equipment can be effectively used in the real hot cell operation. Also, the implemented virtual mock-up of the hot cell can be effectively used in analyzing the various hot cell operation and in enhancing the reliability and safety of the spent fuel management.

• Journal of the Korea Society of Computer and Information
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• v.25 no.4
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• pp.55-61
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• 2020

In this paper, we present a novel approach to efficiently control the location of NPC(Non-playable characters) in the interactive virtual world such as game, virtual reality. To control the NPC's movement path, we first calculate the main trajectory based on the user's path, and then move the NPC based on the weight map. Our method constructs automatically a navigation mesh that provides new paths for NPC by referencing the user trajectories. Our method enables adaptive changes to the virtual world over time and provides user-preferred path weights for smartagent path planning. We have tested the usefulness of our algorithm with several example scenarios from interactive worlds such as video games, virtual reality. In practice, our framework can be applied easily to any type of navigation in an interactive world.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.2
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• pp.216-224
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• 2000

The spatial layout planning system allocates rectangular resources in the limited space according to user requirements, This system also can optimizes the spatial allocation problem to maximize the user's requirement. The spatial layout planning Problems for this system can be solved by searching a wide area of space since this problem entails the non-polynomial algorithm. By accommodating the user's dynamic requirements, the modification of a specific space and the redesign of the whole area can be accomplished. In this paper, the spatial layout planning problem is solved efficiently with a resource allocation method based on CSP. The dynamic constraints by adding user requirements are accommodated through the intelligent user Interface. The 3-D layout on the web environment by using VRML is also shown for providing for the visual verification of the 2-D layout and, thereafter, the additional modification of the 2-D layout.

• 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.