• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.190-198
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• 2020

For domestic urban railways, which have a 19.7% aging rate, a performance evaluation is necessary to establish capital improvement investment plans. The performance evaluation, which was recently enacted in the relevant law, points out the excessive time and effort for acquiring data and evaluation. This study developed a performance evaluation simulation prototype using a virtual reality (VR) method to use as training contents for railway performance evaluations. The practical use of the VR technique to reduce the working time under poor environment conditions was confirmed through a literature review. A survey and consultation were conducted for urban railway experts to determine the weight of the performance evaluation items and the facility breakdown structure. This information was utilized to develop performance evaluation sheets for simulation. Based on the evaluation sheet, a training content prototype that evaluates the performance of platform safety doors was developed using VR techniques with HTC VIVE equipment. VR simulation tests were conducted for six players, and the prototype was sufficiently advantageous for a visual confirmation of the facility information. The result is expected to be useful for engineers to understand the performance evaluation process efficiently before an actual performance evaluation of urban railway facilities.

• Journal of the Korea Convergence Society
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• v.12 no.5
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• pp.139-145
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• 2021

Through this study, we intend to study user satisfaction in order to verify whether there is a need for full-scale research, development and commercialization of document viewers in a VR environment. VR content consists of realistic 3D graphics and 360-degree video, and provides a synesthesia experience and immersion. We developed and tested a VR document viewer prototype that can utilize this concept as a document viewing system. It can act as a viewer that provides an interactive viewing environment according to the user's body interaction and the direction of the field of view, and it can be said that the feature of VR document viewer is that it can draw the user's high level of immersion and concentration when using the viewer. The developed prototype was tested in a test group consisting of 100 VR experiences and device owners for about 1 hour and 3 days a day, and then a questionnaire survey in the form of a fixed selection question was conducted. This study is a prototype study of a document viewer suitable for a virtual reality environment, and can lead to a sense of immersion when reading a document, and suggest a new document viewer direction that is effective for visual fatigue and visual perception of the document.

• Journal of Broadcast Engineering
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• v.27 no.6
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• pp.848-859
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• 2022

This paper presents a novel 360-degree video streaming system for large-scale immersive displays and its ongoing implementation. Recent VR systems aim to provide a service for a single viewer on HMD. However, the proposed 360-degree video streaming system enables multiple viewers to explore immersive contents on a large-scale immersive display. The proposed 360-degree video streaming system is being developed in 3 research phases, with the final goal of providing 6DoF. Currently, the phase 1: implementation of the 3DoF 360-degree video streaming system prototype is finished. The implemented prototype employs subpicture-based viewport-dependent streaming technique, and it achieved bit-rate saving of about 80% and decoding speed up of 543% compared to the conventional viewport-independent streaming technique. Additionally, this paper demonstrated the implemented prototype on UCSB AlloSphere, the large-scale instrument for immersive media art exhibition.

• Journal of the HCI Society of Korea
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• v.2 no.2
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• pp.45-51
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• 2007

Space planning is one of the popular applications of VR technology including interior design, architecture design, and factory layout. In order to provide easier methods to accommodate physical objects into virtual space planning task, we suggest applying mixed reality (MR) interface. We describe our hardware and software of our MR system designed according to requirements of the application domain. In brief, our system hardware consists of a video see-through display with a touch screen interface, mounted on a mobile platform, and we use screen space 3D manipulations to arrange virtual objects within the MR scene. Investigating the interface with our prototype implementation, we are convinced that our system will help users to design spaces in more easy and effective way.

• The Journal of Society for e-Business Studies
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• v.4 no.3
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• pp.25-42
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• 1999

As todays manufacturers and business organizations are struggling to compete in the global marketplace, they are concentrating on the efficient use of numerous information on design, development production, testing, distribution, and maintenance of products throughout their whole life cycles. To meet these organizations demands on information integration, the CALS has been recently focused as a dominant philosophy. In this paper, we introduce the computer supports for engineering CALS in which the engineering process at an initial phase of product development is simultaneously and collaboratively peformed. The proposed system supports the following functions: a virtual prototyping, a distributed collaborative design, and engineering information management. We have conformed to CORBA (Common Object Request Broker Architecture) standard to support interoperability between distributed objects and have used JAVA to support cross-platform and distributed user access to the system on the Web. Under this system, multidisciplinary design teams in engineering CALS environment can collaboratively perform their tasks, share design information and communicate with each other on the Web.

• Journal of Power Electronics
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• v.14 no.6
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• pp.1147-1156
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• 2014

This study proposes a quasi-fixed-frequency hysteresis current tracking control strategy for modular multilevel converters (MMCs) on the basis of voltage partition principle. First, by monitoring the grid voltage and the deviation between the output and reference currents, the output voltage is determined, thus prompting the output current to quickly and efficiently track the given current. Second, the voltages of the upper/lower capacitor of the arm and the voltages between the upper and lower arms are balanced by combining these arms with virtual loop mapping and arm voltage balance control, respectively. In particular, the proposed method is designed for any level and number of sub-modules. The validity of the proposed method is verified by simulations and experimental results of a five-level MMC prototype.

• Korean Journal of Computational Design and Engineering
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• v.4 no.2
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• pp.87-99
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• 1999

We developed a Part Information Brokering System, namely PIBS, that can inter-link part suppliers and buyers using WWW(World Wide Web). The major contribution of this paper is that the system provides a 3D collaboration environment that enables multiple users to share the same workspace where they cooperatively manipulate part features in real time. PIBS carries out two major functions: one to maintain part data in a part library, and the other to provide the means for the clients to cooperate. An object-oriented database is used for the part library which stores apart information registered by part suppliers. VRML(Virtual Reality Modeling Language) the ISO standard for 3D visualization on WWW, is used to represent 3D part models. Several Java programs have been implemented to support synchronous and a synchronous communication of the 3D models. Once the users are interconnected through the system, a user's manipulation of part objects is transparently and instantaneously transmitted to the others. This means that all the participants can are the same view and movement of the 3D part models. Since the system is developed using a Java applet-server architecture, it requires no additional software other than standard web browser. The prototype system has been successfully implemented, and demonstrated its applicability to virtual 3D part information sharing.

• Architectural research
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• v.19 no.1
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• pp.1-6
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• 2017

Over the past decade, building information modeling (BIM) has gained a foothold in the construction sector. However, as digital data generated in the virtual space of a computer environment, BIM-based data have an inherent limitation in their application efficacy under field conditions. To overcome this, the present study employs augmented reality (AR) to reduce the discrepancy between the digital data generated in virtual spaces and real-world conditions. We assessed the potential applicability of an AR-based interface by analyzing existing examples of Apple, Google, and Facebook, which reflect the recent developments of technologies focusing on user experience. We then proceeded with an AR study, restricting the scope of application to a mobile environment in which an efficient information transmission between a digital model and real life can take place. Object-oriented software engineering was employed to ensure an efficient implementation of a BIM-based AR system for campus space management (CSM) in a mobile environment. Finally, we conducted a module test to check the reliability of the CSM method by using an AR-based mobile system with a prototype of the model used in university campuses, and extracted and itemized the supplementary requirements for CSM by using BIM tools for running AR applications.

• Journal of Korea Game Society
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• v.17 no.6
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• pp.7-18
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• 2017

This year, global IT companies such as Google, Apple, and Facebook launched a mobile augmented reality platform. Existing augmented reality technology required a special device such as AR glass or tango phone, but now it will be easy to experience augmented reality in general Android phone and iPhone. The mobile augmented reality game market, which has been attracting interest since the Pokemon game, is expected to become more active. In this article, we introduce augmented reality platforms technology for mobile augmented reality game and mobile augmented reality games including ETRI prototype centered on user interface.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.1
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• pp.23-33
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• 2018

In the general manual feeder of an LED lighting assembly system, many workers are needed to supply parts to the main conveyor. The automatic feeder for modern automation lighting assembly systems consists of a completely automated feeding system and a magazine system that supplies the parts automatically. A standardized LED panel and diffusion cover is stacked in the cartridge of the magazine system. The structural safety of the automatic feeding system with regard to handling the load from the panels and covers stored in the cartridge should be guaranteed. LED convergency lighting modules are assembled using two LED panels and one diffusion cover in an automatic feeder. In this study, the structural safety and fatigue life of the automatic feeder and magazine were analyzed by considering the load generated in the automatically assembled LED convergency lighting system. In addition, the dynamic behavior of each auto-feeding system and magazine delivery system was visualized, and the working process was evaluated via dynamic simulation using a virtual engineering method. A tack time table for automatic feeding systems was derived by developing a virtual prototype.