• Electronics and Telecommunications Trends
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• v.34 no.3
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• pp.13-22
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• 2019

Although virtual reality technology may not be deemed as having a satisfactory quality for all users, it tends to incite interest because of the expectation that the technology can allow one to experience something that they may never experience in real life. The most important aspect of this indirect experience is the provision of immersive 3D audio and video, which interacts naturally with every action of the user. The immersive audio faithfully reproduces an acoustic scene in a space corresponding to the position and movement of the listener, and this technology is also called spatial audio. In this paper, we briefly introduce the trend of spatial audio technology in view of acquisition, analysis, reproduction, and the concept of MPEG-I audio standard technology, which is being promoted for spatial audio services.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.4
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• pp.125-131
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• 2020

In order to study the correlation between the pilot's cognitive ability and recovery ability by applying a physical element that can cause spatial loss of position to the pilot, a turntable was installed on the top of the motion system to give a quantitative rotational error. We propose a method of simulating flight movement to reduce a difference in feeling and an intuitive method of forward kinematic analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.77-85
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• 2018

Recently, many people have attempted to combine the 4th industry in various fields. Citizen participation has also become more important in the policy making and decision making process. Therefore, this study examined ways to encourage citizen participation by integrating the 4th industry in the field of urban planning and design. The research method was to design street space using virtual reality, and to examine the preference of design and the satisfaction of using a virtual reality device for Cheongju citizens and residents. The main result is that the use of VR in the design process of street space can achieve a sufficient outcome in terms of inducing resident participation. The opinions of the respondents before and after the VR experience were different from each other. After the VR experience, understanding, participation and interest in design were improved. On the other hand, during the course of the study, there are many difficulties in obtaining a place that satisfied the conditions of the PC-VR equipment. Although it can be used by connecting a smart phone and a VR device, the constraint of free movement and degradation of the graphic quality are inevitable. In addition, it is difficult to operate simple interfaces because VR devices are not yet popularized. Accordingly, it will be necessary to popularize and commercialize VR equipment and establish a legal basis.

• Journal of Korea Game Society
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• v.10 no.6
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• pp.157-168
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• 2010

A terrain is an essential element for constructing a virtual world in which game characters and objects make various interactions with one another. Creating a terrain requires a great deal of time and repetitive editing processes. This paper presents a 3D terrain reconstruction system to create 3D terrain in virtual space based on real terrain data. In this system, it converts the coordinate system of the height maps which are generated from a stereo camera and a laser scanner from global GPS into 3D world using the x and z axis vectors of the global GPS coordinate system. It calculates the movement vectors and the rotation matrices frame by frame. Terrain meshes are dynamically generated and rendered in the virtual areas which are represented in an undirected graph. The rendering meshes are exactly created and updated by correcting terrain data errors. In our experiments, the FPS of the system was regularly checked until the terrain was reconstructed by our system, and the visualization quality of the terrain was reviewed. As a result, our system shows that it has 3 times higher FPS than other terrain management systems with Quadtree for small area, improves 40% than others for large area. The visualization of terrain data maintains the same shape as the contour of real terrain. This system could be used for the terrain system of realtime 3D games to generate terrain on real time, and for the terrain design work of CG Movies.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.6
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• pp.57-66
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• 2005

In this paper, a new rehabilitation training system was developed to improve equilibrium sense by combining virtual reality technology with a fixed exercise bicycle. The subjects consisted of two groups. A group of young people, was compared against a group of elderly. We measured three different running modes of virtual bicycle system with two successive sets. The parameters measured were running time, velocity, the weight movement, the degree of the deviation from the road, and the variables about the center of pressure. The repeated training, our results showed that the running capability of the elderly improve compared. In addition, it was found out that the ability of postural control and the equilibrium sense was improved with the presentation of the visual feedback information of the distribution of weight. From the results of this experiment, we showed that our newly developed system might be useful in the diagnosis of equilibrium sense or in the improvement of the sense of sight and, somatic, and vestibular sense of the elderly in the field of rehabilitation training.

• Journal of Platform Technology
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• v.11 no.3
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• pp.32-44
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• 2023

A blockchain bridge (hereinafter referred to as "bridge") is a service that enables the transfer of assets between blockchains. A bridge accepts virtual assets from users and delivers the same virtual assets to users on other blockchains. Users use bridges because they cannot transfer assets to other blockchains in the usual way because each blockchain environment is independent. Therefore, the movement of assets through bridges is not traceable in the usual way. If a malicious actor moves funds through a bridge, existing asset tracking tools are limited in their ability to trace it. Therefore, this paper proposes a method to obtain information on bridge usage by identifying the structure of the bridge and analyzing the event logs of bridge requests. First, to understand the structure of bridges, we analyzed bridges operating on Ethereum Virtual Machine(EVM) based blockchains. Based on the analysis, we applied the method to arbitrary bridge events. Furthermore, we created an automated tool that continuously collects and stores bridge usage information so that it can be used for actual tracking. We also validated the automated tool and tracking method based on an asset transfer scenario. By extracting the usage information through the tool after using the bridge, we were able to check important information for tracking, such as the sending blockchain, the receiving blockchain, the receiving wallet address, and the type and quantity of tokens transferred. This showed that it is possible to overcome the limitations of tracking asset movements using blockchain bridges.

• Korean Journal of Labor Studies
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• v.23 no.1
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• pp.1-45
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• 2017

The aim of this study is to analyze the process of the struggle and bargaining for the change of the employment position of the irregular (in-house subcontracted) workers being at work in the Hyundai Motor Company (HMC) plants into the status of the regular employee of the company, and evaluate the results and limitation of the irregular workers' movement. Since the unionization of irregular workers in 2003, they have carried on the struggle against and the bargaining with the HMC, over the past 10 years and more, making claims for abolishing 'illegal temporary agency work' and for converting their positions into the regular ones. The HMC have gradually altered a confrontational stance against the workers' claim at the early stage, into the bargaining relationship with irregular workers' union. Eventually, the collective agreement on the 'special hiring' of about six thousands irregular workers by the HMC was reached in 2016. We attempt to analyze in depth the overall process by dividing three phases of the movement, according to the criteria of the relationship between the alliance and conflict system, and the cycle of protests of irregular workers. Furthermore, we try to trace the long and winding path of the movement, focusing on the cooperation/conflict relationship within the movement's alliance system, the confrontation/bargaining relationship between the movement and the conflict system, and the critical roles played by mediators (or third parties) between two systems. In the conclusion of the paper, we evaluate the results and limitation of the irregular workers' movement upon the basis of the following points; the convergence of the workers' demands into the prime goal of 'becoming HMC's regular employee,' the breakaway of regular workers' union from the movement's alliance system, and a virtual extinction of irregular workers' union after the final labor-management agreement of 2016.

• Progress in Medical Physics
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• v.29 no.1
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• pp.1-7
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• 2018

The $TomoTherapy^{(R)}$ beam-delivery method creates helical beam-junctioning patterns in the dose distribution within the target. In addition, the dose discrepancy results in the particular region where the resonance by pattern of dose delivery occurs owing to the change in the position and shape of internal organs with a patient's respiration during long treatment times. In this study, we evaluated the dose pattern of the longitudinal profile with the change in respiration. The superior-inferior motion signal of the programmable respiratory motion phantom was obtained using AbChes as a four-dimensional computed tomography (4DCT) original moving signal. We delineated virtual targets in the phantom and planned to deliver the prescription dose of 300 cGy using field widths of 1.0 cm, 2.5 cm, and 5.0 cm. An original moving signal was fitted to reflecting the beam delivery time of the $TomoTherapy^{(R)}$. The EBT3 film was inserted into the phantom movement cassette, and static, without the movement and with the original movement, was measured with signal changes of 2.0 s, 4.0 s, and 5.0 s periods, and 2.0 mm and 4.0 mm amplitudes. It was found that a dose fluctuation within ${\pm}4.0%$ occurred in all longitudinal profiles. Compared with the original movement, the region of the gamma index above 1 partially appeared within the target and the border of the target when the period and amplitude were changed. Gamma passing rates were 95.00% or more. However, cases for a 5.0 s period and 4.0 mm amplitude at a field width of 2.5 cm and for 2.0 s and 5.0 s periods at a field width of 5.0 cm have gamma passing rates of 92.73%, 90.31%, 90.31%, and 93.60%. $TomoTherapy^{(R)}$ shows a small difference in dose distribution according to the changes of period and amplitude of respiration. Therefore, to treat a variable respiratory motion region, a margin reflecting the degree of change of respiration signal is required.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.711-719
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• 2021

EBS has been producing numerous educational contents with traditional virtual studio production systems since the early 2000s and applied AR video production system in October 2020, twenty-years after. Although the basic concept of synthesizing graphic elements and actual image in real time by tracking camera movement and lens information is similar to the previous one but the newly applied AR video production system contains some of advanced technologies that are improved over the previous ones. Marker tracking technology that enables camera movement free and position tracking has been applied that can track the location stably, and the operating software has been applied with Unreal Engine, one of the representative graphic engines used in computer game production, therefore the system's rendering burden has been reduced, enabling high-quality and real-time graphic effects. This system is installed on a crane camera that is mainly used in a crane shot at the live broadcasting studio and applied for live broadcasting programs for children and some of the videos such as program introductions and quiz events that used to be expressed in 2D graphics were converted to 3D AR videos which has been enhanced. This paper covers the effect of introduction and application of the AR video production system on EBS content production and the future development direction and possibility.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.65-73
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• 2006

Network based VPN(Virtual Private Network) using MPLS(Multiprotocol Label Switching) technology, called PE(Provider Edge router) based MPLS VPN, is regarded as a good solution for intranets or ext3nets because of the low cost and the flexibility of the service provision. In this paper, we describe a mechanism that allows the VPN users to move from one site to another site of the VPN network based on the BGP-E MPLS technology. This mechanism is designed for PE(Provider Edge) routers of the backbone network. PE routers connected to the VPN sites establish a new MPLS path to the mobile node after they detect movement of the mobile VPN node. The new location may belong to the same VPN or to different VPN. We desisted VPN management and control functions of the PE routers in order to interface with the Mobile IP protocol and support the QoS mechanism. The pilot implementation and performance measurement were carried out on a simulation using COVERS tool.