• Journal of Broadcast Engineering
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• v.27 no.5
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• pp.629-637
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• 2022

This study is an experiment on the use of RDW(Redirected Walking) technology, which helps users to hardly feel the difference of user movement in the limited physical space and the extended virtual space when the user moves while wearing the HMD in the real world. The RDW function installed in 3D space realization software such as Unity3D is used to induce the user's redirection by slightly distorting the virtual space according to the user's point of view. However, if the RDW distortion rate is used excessively, dissonance is highly likely to occur. In particular, it is easy to make errors that cause cybersickness of users. It is important to obtain the RDW data value in the virtual environment so that the user does not feel fatigue and cybersickness even after wearing the HMD for a long time. In this experiment, it was tested whether the user's RDW was safely implemented, and item and obstacle arrangement data were obtained through this experiment. The RDW data obtained as a result of the experiment were used for item placement and obstacle placement in the virtual space.

• Structural Engineering and Mechanics
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• v.81 no.3
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• pp.293-303
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• 2022

As infrastructure ages and traffic load increases, serious public concerns have arisen for the well-being of bridges. The current health monitoring practice focuses on large-scale bridges rather than short span bridges. However, it is critical that more attention should be given to these behind-the-scene bridges. The relevant information about the construction methods and as-built properties are most likely missing. Additionally, since the condition of a bridge has unavoidably changed during service, due to weathering and deterioration, the material properties and boundary conditions would also have changed since its construction. Therefore, it is not appropriate to continue using the design values of the bridge parameters when undertaking any analysis to evaluate bridge performance. It is imperative to update the model, using finite element (FE) analysis to reflect the current structural condition. In this study, a FE model is established to simulate a concrete culvert bridge in New South Wales, Australia. That model, however, contains a number of parameter uncertainties that would compromise the accuracy of analytical results. The model is therefore updated with a neural network (NN) optimisation algorithm incorporating Monte Carlo (MC) simulation to minimise the uncertainties in parameters. The modal frequency and strain responses produced by the updated FE model are compared with the frequency and strain values on-site measured by sensors. The outcome indicates that the NN model updating incorporating MC simulation is a feasible and robust optimisation method for updating numerical models so as to minimise the difference between numerical models and their real-world counterparts.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.587-588
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• 2022

In this paper, we propose a rigid body tracking method in 3D space using 2D passive marker images from multiple motion capture cameras. First, a calibration process using a chess board is performed to obtain the internal variables of individual cameras, and in the second calibration process, the triangular structure with three markers is moved so that all cameras can observe it, and then the accumulated data for each frame is calculated. Correction and update of relative position information between cameras. After that, the three-dimensional coordinates of the three markers were restored through the process of converting the coordinate system of each camera into the 3D world coordinate system, the distance between each marker was calculated, and the difference with the actual distance was compared. As a result, an error within an average of 2mm was measured.

• Journal of Digital Contents Society
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• v.7 no.4
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• pp.287-294
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• 2006

Mass-customization is fast growing a segment of the apparel market. 2D Virtual wearing system is one of visual support tools that make possible to sell apparel before producing and reduce the time and costs related to product development and manufacturing in the world of apparel mass-customization. This paper is related to fabric color mapping method for 2D image-based virtual wearing system. In proposed method, clothing shape section of interest is segmented from a clothes model image using a region growing method, and then mapping a new fabric color selected by user into it based on its intensity difference map is processed. With the proposed method in 2D virtual wearing system, regardless of color or intensity of model clothes, it is possible to virtually change the fabric color with holding the illumination and shading properties of the selected clothing shape section, and also to quickly and easily simulate, compare, and select multiple fabric color combinations for individual styles or entire outfits.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.201-207
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• 2008

The purpose of this study was to examine the Roche technique performed by three male subjects in 2003 Taegu World Students Game. Conclusions are as followed. If the angular momentum was increased to counter-clockwise on voulting, the momentum acted like an interrupting factor of body spinning force. The biggest body angle was at VTD phase and the smallest was at BTO phase. At the phase of contacting on vaulting board and taking off from the vaulting board, the biggest personal angle difference between VTD and BTO was found. As the Roche technique was needed not only to fly high but also to increase body spinning rate, the projection angles of Roche technique were showed smaller than those of Cuervo technique. The angular velocity was peak during 2 times forward turn phase. The angular momentum was influenced by angular velocity from BTO and VTD phase.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.105-113
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• 2015

This paper investigated Korean popular entertainment (K-entertainment, hereafter) tourism using theory of intention-behavior. Dividing the sample of international visitors to Seoul into the groups of "inclined actors", "inclined abstainers", and "disinclined abstainers," we examined the factors affecting such a division. The results showed that between the inclined actors and the inclined abstainers, there was no significant difference in the years of exposure to K-entertainment contents or the frequency of going to K-entertainment performance in the past. In contrast, the inclined actors were found to have a greater level of knowledge, ability, and cooperation compared to the inclined abstainers. In addition, we found that the K-entertainment performance in Korea was perceived as a substitute, rather than a complement to the performance held elsewhere in the world. Our findings suggest that interests in K-entertainment alone are not sufficient to drive the international visitors' intention to the action of attending K-entertainment performance during their visit to Korea. To this end, this study implies that it is necessary to design attractive tourism packages that include K-entertainment performance.

• Journal of Science Education
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• v.32 no.1
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• pp.1-18
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• 2008

We investigated 8th grade science textbooks and their instructor's manuals treating the ideal condition for isochronism of a simple pendulum. The isochronism, i.e. the period is independent of amplitude, is satisfied only if the amplitude is very small. This is so called "ideal condition" for isochronism of a simple pendulum. Most textbooks and instructor's manuals are found not to state this ideal condition properly, which often leads to the deviation between experimental data and theoretical calculation. This difference between theoretical and experimental results makes students to create a sense of alienation from the real world and eventually keeps them away from physics. We thus study the cycloidal pendulum as an alternative method to test the isochronism regardless of amplitude and discuss the practical utility of it in class.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.4
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• pp.135-143
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• 2012

Remote sensing which observes repeatedly the whole Earth and GIS-based decision-making technology have been utilized widely in disaster management such as early warning monitoring, damage investigation, emergent rescue and response, rapid recovery etc. In addition, various countermeasures of national level to collect timely satellite imagery in emergency have been considered through the operation of a satellite with onboard multiple sensors as well as the practical joint use of satellite imagery by collaboration with space agencies of the world. In order to respond heavy snowfall disaster occurred on the east coast of the Korean Peninsula in February 2011, snow-covered regions were analyzed and detected in this study through NDSI(Normalized Difference Snow Index) considering reflectance of wavelength for MODIS sensor and change detection algorithm using satellite imagery collected from International Charter. We present the application case of National Disaster Management Institute(NDMI) which supported timely decision-making through GIS spatial analysis with various spatial data and snow cover map.

• Journal of the Korea Safety Management & Science
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• v.6 no.4
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• pp.83-97
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• 2004

The growing importance of product quality is becoming more and more daily apparent as we enter the age of globalization around the world. And the product safety is getting more focus as well as product quality. As a result, many domestic companies are putting a lot of emphasis on safety measures and management activities and these companies' products are mainly superior to other companies' product. When we separate the product quality procedure into 3 steps, i.e. quality secure-quality confirm-quality guarantee, of course the 1st step is the most important, but also End step of product quality confirm process is important. And in mass production environment, sampling inspection is more desirable than the 100 % inspection procedure. As a part of globalization trend, KS system is also being revised and reestablished based on ISO, IEC, etc. which are based on international standard. Conventional KS sampling inspection standards were in many areas quite different from ISO sampling standards, only KS A 3102, 3104, 3151 are left and the rest become obsolete, and even the ones that are still around are planned to the gone step by step. It has been already 3 years since the new KS A ISO 2859-0-3 sampling inspection process has been established which the abolition of the popular KS A 3101, KS A 3105, KS A 3109, yet the implementation rate is very slow. This study will attempt to analyze the new KS A ISO 2859-2 and KS A ISO 2859-3, and try to understand the difference as that the new standard can be easily understood and used widely among companies, by using examples. Our attempt is to help implement with the companies with active safety involvement but the final result can be spread among other companies as well in the near future.

• KIEAE Journal
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• v.9 no.5
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• pp.85-96
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• 2009

This study analyzed a characteristic by types of urban regeneration helping the establishment of urban identity under social condition change. It will be foundation of sustainable urban development with strategy that secures world-wide competitive power. For this, sample cases that established identity from urban regeneration were reviewed about the main subject and the supporting subject in business side and hardware, software, system, and finance in design factors. 4samples each in inheritance intensification type and change creation type were selected and analyzed. The result said it is most effective to establish urban identity when inheritance intensification type is the private-centered for urban regeneration. And it is better to do the project that the main subject and the supporting subject are taken by the private or the private-leading partnership. It is necessary to manage the region and plan events with software design factors more than hardware design factors. In addition, for urban identity, it was found to be desirable to utilize and preserve fully current resources such as historical scenery and activate the communities than making new facilities. On the contrary, the project based on change creation type needs to be under the public management with innovative idea. Also, when it comes to design factors, facilities related to culture and art and community spaces should open and run actively. It is important for the region to improve its image by New design style such as TOD. In software side, it is important to manage the region by monitoring about urban regeneration business and solve social mix and employment problem. On the other hand, in terms of system and administration, both types don't show a difference in urban identity establishment, since it is same that both should make partnership and get a support of subsidy to be most effective.