• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1208-1211
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• 1996

In this paper, an efficient and robust robot path planning technique is discussed. Concentric Ripple Edge Evaluation and Progression( CREEP ) algorithm[1] has been elaborated and expanded to carry out 3-D path planning. Like the 2-D case, robot can always find a path, if one exists, in a densely cluttered, unknown and unstructured 3-D obstacle environment. 3-D space in which the robot is expected to navigate is modeled by stacking cubic cells. The generated path is resolution optimal once the terrain is fully explored by the robot or all the information about the terrain is given. Path planning times are significantly reduced by local path update. Accuracy and efficiency of wave propagation in CREEP algorithm are achieved by virtual concentric sphere wave propagation. Simulations in 2-D and 3-D spaces are performed and excellent results are demonstrated.

• Journal of the Semiconductor & Display Technology
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• v.17 no.1
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• pp.88-92
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• 2018

Currently drone industry has become one of the fast growing markets and the technology for unmanned aerial vehicles are expected to continue to develop at a rapid rate. Especially small unmanned aerial vehicle systems have been designed and utilized for the various field with their own specific purposes. In these fields the path planning problem to find the shortest path between two oriented points is important. In this paper we introduce a path planning strategy for an autonomous flight of unmanned aerial vehicles through reinforcement learning with self-positioning technique. We perform Q-learning algorithm, a kind of reinforcement learning algorithm. At the same time, multi sensors of acceleraion sensor, gyro sensor, and magnetic are used to estimate the position. For the functional evaluation, the proposed method was simulated with virtual UAV environment and visualized the results. The flight history was based on a PX4 based drones system equipped with a smartphone.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.68-73
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• 2008

Recently, construction management technology based on information technology is being changed from numerical information management to visual information management with virtual reality (VR) method. This study suggests a IDEF0 model for development process of VR system for the planning, design and construction phases of civil engineering project. And the simulation functions by each phase based on VR were developed by using the suggested IDEF0 model. The developed virtual construction system can be used as an effective design review tool by visualization of design information based on 3D object.

• Journal of International Society for Simulation Surgery
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• v.2 no.2
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• pp.71-75
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• 2015

To overcome limitations of conventional diagnosis and planning for orthognathic surgery, surgeons have begun to use 3-dimensional (3D) virtual simulation to plan complex orthognathic surgery. In many literatures, it has shown that better surgical outcome achieved with 3D virtual simulation than that with conventional methods. But, there is still lack of data about accuracy of maxillary segmental surgery with 3D virtual simulation. The purpose of this paper was to report the case of maxillary segmental orthognathic surgery with 3D virtual simulation and to assess the actual surgical outcome. Though the result was clinically acceptable, discrepancy between 3D simulation and actual surgery was not superior compared with conventional method. The accuracy of 3D simulation surgery and intermediate wafer fabrication for maxillary segmental surgery needs to be improved. Advancement in 3D software program and careful surgical technique will make it more precise and reliable method.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1166-1172
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• 2003

The extremely strong competition among the world automobile industries has introduced the concept of PLM in the total production activities, one of whose major components is VM(Virtual Manufacturing). If the production lines are equipped with robots, the application of OLP in the virtual space is fully mature. However, in the point of the investment's and the maintenance's view, there are always some activities, which can not be automated: for example, typically the manual welding for prefixing in the automobile body shop and the material loading. Process planning for these activities, therefore, are decided mainly by experiences, which caused many repeated rework of the processes and the inconvenience of the workers, and resulted consequently in the reduction of the productivity and the safety of the workers. In this paper, the optimal dimension of the welding gun and its handle position and the optimal working path is simulated and decided by use of DELIMN/IGRIP and DELMIA/Ergo and the working area modelized in the virtual workcell of DELMIA.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.323-325
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• 2021

With the recent revitalization of virtual reality and game industries, digital therapeutics for medical purposes are emerging. Digital therapeutics refer to sports-based therapeutics such as virtual reality contents and games that are effective in preventing, managing, and treating diseases, not drugs. Through this study, we plan and develop contents for healing and brain enhancement using virtual reality technology as a therapeutic digital therapy. Through this, it can help to improve the brain of children who are dependent on electronic devices in the digital age and rarely use their brains.

• Journal of the Korean Society of Safety
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• v.33 no.2
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• pp.76-85
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• 2018

The interest in the Building Information Modeling (BIM) technology has risen remarkably due to the effects on construction work period reduction, cost reduction, work safety improvement, and other factors. In civil engineering field, BIM applications mainly focus on data modeling and virtual construction. In this study, we present the BIM-based virtual construction and analyze the effects of BIM for the railway facilities so that the conventional approach to the equipment operation plan can be improved in order to prevent safety accidents which can result from unclear information during the operation plan. The BIM-based virtual construction technology is applied to establish the construction plan for the site with constraints, the installation of steel girder needs to be completed, avoiding interference with the existing high-speed railway operation within a given limited time. A virtual construction model consisting of topography, structures, equipments, and avatar was built and more detailed model, including safety guard rails, was then created. Specifications of the construction equipment were input as a database, and the virtual construction model was manipulated in the equipment operation planning. Through the BIM-based virtual construction, including the verification of alternative construction method, 311 million won was saved and the construction period was shortened by 87 days compared to the original plan. In addition, it was shown that the interest and participation of the construction workers can be increased by providing the 3D virtual scene for real construction work and various safety hazards occurring during equipment operation can be effectively removed in advance by the interactive worker education.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.230-240
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• 2020

To develop a virtual world-based immersive tutoring system, we would like to develop a simulation in the spatial aspect to maximize the diversity and realism of the situation. This implementation requires the modeling of virtual space as well as the knowledge and intelligent thinking functions of virtual humans. First, information structures are needed to simulate the hierarchical and multifaceted composition of space and the corresponding knowledge of virtual humans. Specifically, four structures for 2.5D spatial distribution expression, complex spatial relationship expression, object expression, and temporal and spatial representation of events are developed respectively. It then uses these expressed knowledge to develop the spatial thinking function of virtual humans needed to make spatial movement. In general, events have a chain effect on adjacent or connected objects through force, resulting in a variety of situations and reflected in the planning of the next action by the virtual humans involved. For this purpose, the development of events according to historical trends is recorded on the representation structure of time and space. It embodies typical events to demonstrate the feasibility of independent behavior in complex spaces among virtual people.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.145-154
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• 2022

With the real museum changing from a center of viewing to a center of experience and communication, virtual museums have become independent as well as auxiliary and alternative roles for real museums. Therefore, it is necessary to review the concept and meaning of virtual museums and analyze the attributes of each exhibition type. This paper categorizes the exhibition types of virtual museums into four categories and analyzes the interaction methods of each exhibition type. The essential characteristics of interaction subjects affect all four types, but the method of virtual expression is distinguished, and the exhibition type that actively utilizes the virtuality of exhibition space and work expands the user's experience and communication. In this study, various forms and methods of construction of virtual museums can be explored by providing characteristics and considerations for each type of exhibition during the planning and construction of virtual museums.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.30 no.2
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• pp.71-90
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• 2021

The virtual patient dataset is a collection of diagnostic data from various sources acquired from a single patient into a coordinate system of three-dimensional visualization. Virtual patient dataset makes it possible to establish a treatment plan, simulate various treatment procedures, and create a treatment planning delivery device. Clinicians can design and simulate a patient's smile on the virtual patient dataset and select the optimal result from the diagnostic process. The selected treatment plan can be delivered identically to the patient using manufacturing techniques such as 3D printing, milling, and injection molding. The delivery of this treatment plan can be linked to the final prosthesis through mockup confirmation through provisional restoration fabrication and delivery in the patient's mouth. In this way, if the diagnostic data superimposition and processing accuracy during the manufacturing process are guaranteed, 3D digital smile design simulated in 3D visualization can be accurately delivered to the real patient. As a clinical application method of the virtual patient dataset, we suggest a decision-making method that can exclude occlusal adjustment treatment from the treatment plan through the digital occlusal pressure analysis. A comparative analysis of whole-body scans before and after temporomandibular joint treatment was suggested for adolescent idiopathic scoliosis patients with temporomandibular joint disease. Occlusal plane and smile aesthetic analysis based on the virtual patient dataset was presented when treating patients with complete dentures.