• The Journal of Korea Robotics Society
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• v.17 no.1
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• pp.8-15
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• 2022

In this paper, we proposed the method of virtual reality-based surgical navigation to reproduce the pre-planned position and angle of the pedicle screw in spinal fusion surgery. The goal of the proposed method is to quantitatively save the surgical plan by applying a virtual guide coordinate system and reproduce it in the surgical process through virtual reality. In the surgical planning step, the insertion position and angle of the pedicle screw are planned and stored based on the virtual guide coordinate system. To implement the virtual reality-based surgical navigation, a vision tracking system is applied to set the patient coordinate system and paired point-based patient-to-image registration is performed. In the surgical navigation step, the surgical plan is reproduced by quantitatively visualizing the pre-planned insertion position and angle of the pedicle screw using a virtual guide coordinate system. We conducted phantom experiment to verify the error between the surgical plan and the surgical navigation, the experimental result showed that target registration error was average 1.47 ± 0.64 mm when using the proposed method. We believe that our method can be used to accurately reproduce a pre-established surgical plan in spinal fusion surgery.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2211-2216
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• 2005

This paper describes a novel navigation algorithm using a locomotion interface with two 6-DOF parallel robotic manipulators. The suggested novel navigation system can induce user's real walking and generate realistic visual feedback during navigation, using robotic manipulators. For realistic visual feedback, the virtual environment is designed with three components; 3D object modeler for buildings and terrains, scene manager and communication manager component. The walking velocity of the user is directly translated to VR actions for navigation. Finally, the functions of the RPC interface are utilized for each interaction mode. The suggested navigation system can allow a user to explore into various virtual terrains with real walking and realistic visual feedback.

• Proceedings of the Korea Society of Design Studies Conference
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• 2005.05a
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• pp.130-131
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• 2005

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.53-59
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• 2007

A navigation system for virtual environments using low-qualify HMD(head mounted display) must quantize images when the system presents true-color image with restricted number of colors. Such navigation system quantizes an image by using fixed palette. If the system represents an image by using a variable palette which is made considering a region around the viewpoint then user can perceive a virtual environments more vividly because human visual system is sensitive to the colors variation in the region around the viewpoint. In this paper we propose a color quantization algorithm that quantize a region around the viewpoint more finely than other regions at each variation of viewpoint for virtual environments navigation system and compose virtual environments navigation system using proposed algorithm. The system quantizes an image at each variation of viewpoint and shows a quantized image to user through HMD. We tested user preferences for our proposed system and the results show that users preferred our system.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.10-15
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• 2008

This paper describes virtual environment and sensor modeling to analyze and verify the performance of autonomous navigation system. Virtual synthetic environment is constructed with 6 subgroups which cover from virtual environment construction to virtual sensor modeling of real systems. This research is applied to validate and assess performance of concerned algorithms and complex functions for autonomous navigation system based on virtual environment.

• Journal of Game and Entertainment
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• v.2 no.1
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• pp.35-44
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• 2006

Objective of this study is to develop a 3D car navigation system that shows the driving direction to a destination through real-time 3-D panoramic views of the route. For the purpose, a new searching process was established to find the optimal driving direction based on the driver's current location and the real-time traffic situation and the TIP (tour into the picture) method was extended to implement a wide virtual environment. A virtual environment was built up by applying the extended TIP method to the panoramic images taken at a constant distance from a real road, and then, displayed 3-D navigation as clear as the real images. The car navigation system developed in this study provides the optimal driving direction and real-time traffic situation using 2-D navigation module and 3D navigation module.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.6
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• pp.358-366
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• 2006

This paper describes a novel navigation algorithm using a locomotion interface with two 6-DOF programmable foot platforms. When a human walks on the locomotion interface (LI), the walking motions of the human are recognized by several sensors. Then, the sensed information is used by the LI for generation of infinite surfaces for continuous walking and the virtual environments for scene update according to motions of the human walking. The suggested novel navigation system can induce user's real walking and generate realistic visual feedback during navigation. A novel navigation algorithm is suggested to allow natural navigation in virtual environments by utilizing conditions of normal gait analysis. For realistic visual feedback, the virtual environment is designed with three components; 3D object modeler for buildings and terrains, scene manager and communication manager component. From experiments, the subjects were satisfied with the reality of the suggested navigation algorithm using the locomotion interface. Therefore, the suggested navigation system can allow a user to explore into various virtual terrains with real walking and realistic visual feedback.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.772-774
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• 2008

A navigation system for virtual environments using low-quality HMD(head mounted display)must quantize images when the system presents true-color image with restricted number of colors. Such navigation system quantizes an image by using fixed palette. If the system represents an image by using a variable palette which is made considering a region around the viewpoint then user can perceive a virtual environments more vividly because human visual system is sensitive to the colors variation in the region around the viewpoint. In this paper we propose a color quantization algorithm that quantize a region around the viewpoint more finely than other regions at each variation of viewpoint for virtual environments navigation system and compose virtual environments navigation system using proposed algorithm. The system quantizes an image at each variation of viewpoint and shows a quantized image to user through HMD. We tested user preferences for our proposed system and the results show that users preferred our system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.315-320
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• 1999

Obstacle Detection System(ODS) is a essential system for automated vehicle, such as AGV(Automatic Guided Vehicle), mobile robot. Automated vehicle must have a capability to detect and to avoid obstacles to guarantee a safe driving condition. To implement obstacle detection system, virtual bumper concept adapted. Like real bumper in a car, such as in the truck, it protects vehicle from collision using laser distance sensor. When an obstacle(such as other vehicle, building, etc) intrudes this virtual bumper area, a virtual force is calculated and produces necessary strategy to be able to avoid collision. In this paper, simplified virtual bumper concept is presented, and various problems when happens to implement are discussed.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.53-57
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• 2003

The last goof if the study is to develop a law cost and a readily available Virtual Reality (VR) based Ship Handling Simulator using Personal Computer. This paper mainly describes procedures and methods to control the dynamic motions if the 3D ship object with maneuvering coefficients in a virtual navigation world The creation if virtual navigation world, the mathematical background q a ship control, and the construction of the system are also discussed.