• Journal of the Korea Society of Computer and Information
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• v.27 no.8
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• pp.135-142
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• 2022

In this paper, we propose a graph-based user route control for rapidly conducting virus inspections in emergency situations (eg, COVID-19) and a framework that can simulate this on a city map. A^* and navigation mesh data structures, which are widely used pathfinding algorithms in virtual environments, are effective when applied to CS(Computer science) problems that control Agents in virtual environments because they guide only a fixed static movement path. However, it is not enough to solve the problem by applying it to the real COVID-19 environment. In particular, there are many situations to consider, such as the actual road traffic situation, the size of the hospital, the number of patients moved, and the patient processing time, rather than using only a short distance to receive a fast virus inspection.

• Journal of Biomedical Engineering Research
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• v.29 no.6
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• pp.451-456
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• 2008

Total knee arthroplasty(TKA) using computer-assisted navigation has been increased in order to improve the accuracy of femoral and tibial components implantation. Recently, a few clinical studies have reported on the femoral stress fracture after TKA using computer-assisted navigation. The purpose of this study is to investigate the stress concentration around the femoral pin-hole for different pin-hole diameter, the modes of pin penetration by finite element analysis to understand the effects of pin-hole parameters on femoral stress fracture risk. A three-dimensional finite element model of a male femur was reconstructed from 1 mm thick computed tomography(CT) images. The bone was rigidly fixed to a 25 mm above the distal end and 1500 N of axial compressive force and 12 Nm of axial torsion were applied at the femoral head. For all cases, transcortical pin penetration mode showed the highest stress fracture risk and unicortical pin penetration mode showed the lowest stress concentration. Pin-hole diameter increased the stress concentration, but pin number did not increase the stress dramatically. The results of this study provided a biomechanical guideline for pin-hole fracture risk of the computer navigated TKA.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.3
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• pp.282-288
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• 2010

Surgery with the computer navigation system can make it possible to identify important anatomical structures which are difficult to be confirmed with the naked eye in the operation, and has extended their applications in various surgical fields. The head and neck surgery especially requires detailed anatomical knowledges and these knowledges have influences on postoperative functions and esthetics of a patient. In the orthognathic surgery, we should take osteotomies in the precise locations of the jawbones and move segments to the intended positions. There are so many important anatomical structures around the osteotomy-sites in the orthognathic surgery that the prevention of damage to these structures to obtain satisfactory results without any complication. There are vessels of the pterygoid plexus posterior to the pterygoid plate in the maxilla and the mandibular nerve enters the mandibluar foramen in the mandibular ramus. These locations should be confirmed perioperatively to avoid any injury to these structures. The navigation-assisted surgery may be helpful for this purpose. We performed navigational orthognathic surgeries with preoperative CT images and obtained satisfactory results. The osteotomy was performed in the proper location and damaging the surrounding important anatomical structures was avoided by keeping the saw away from them with the real-time navigation. It may be required to develop proper devices and protocols for the navigation-assisted orthognathic surgery.

• Archives of design research
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• v.14 no.3
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• pp.117-125
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• 2001

The 2D based-web contents are limited to implement interactive elements for the users even though the contents are offered in various styles. Using the mouse and keyboards users chose any web contents for themselves beyond the limitation of time and space. They want more interactive style as they become familiar with convenience of web contents. The 3 dimensional web contents integrated with interactive technologies are one of the ways for them There are many researches and commercialization of the interactive web 30 for the past years because it has a lot of user benefits in terms of immersion, realistic expression, and interactivity. It has two types of implementation; one is for 3D polygon based objects, the other is for virtual worlds. This research is focus of on the concept of web interactive 3D, the technical aspects, design elements, and the proposal of navigation methods for the purpose of creating new type of web interactive contents.

• Journal of Digital Contents Society
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• v.16 no.3
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• pp.445-455
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• 2015

According as internet and computer technology develops, the amount of information has increased exponentially, arising from a variety of web authoring tools and is a new web standard of appearance and a wide variety of web content accessibility as more convenient for the web are produced very quickly. However, web documents are put out on a variety of topics divided into some blocks where each of the blocks are dealing with a topic unrelated to one another as well as you can not see with contents such as many navigations, simple decorations, advertisements, copyright. Extract only the exact area of the web document body to solve this problem and to meet user requirements, and to study the effective information. Later on, as the reconstruction method, we propose a web search system can be optimized systematically manage documents.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.8
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• pp.195-202
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• 2018

With the development of location-based applications such as smart phones and GPS navigation, active research is being conducted to protect location and trajectory privacy. To receive location-related services, users must disclose their exact location to the server. However, disclosure of users' location exposes not only their locations but also their trajectory to the server, which can lead to concerns of privacy violation. Furthermore, users request from the server not only location information but also multimedia information (photographs, reviews, etc. of the location), and this increases the processing cost of the server and the information to be received by the user. To solve these problems, this study proposes the EGTC (Enhanced Grid-based Trajectory Cloaking) technique. As with the existing GTC (Grid-based Trajectory Cloaking) technique, EGTC method divides the user trajectory into grids at the user privacy level (UPL) and creates a cloaking region in which a random query sequence is determined. In the next step, the necessary information is received as index by considering the sub-grid cell corresponding to the path through which the user wishes to move as c(x,y). The proposed method ensures the trajectory privacy as with the existing GTC method while reducing the amount of information the user must listen to. The excellence of the proposed method has been proven through experimental results.