• Clinics in Orthopedic Surgery
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• v.10 no.4
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• pp.468-478
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• 2018

Background: The restriction of wrist motion results in limited hand function, and the evaluation of the range of wrist motion is related to the evaluation of wrist function. To analyze and compare the wrist motion during four selected tasks, we developed a new desktop motion analysis system using the motion controller for a home video game console. Methods: Eighteen healthy, right-handed subjects performed 15 trials of selective tasks (dart throwing, hammering, circumduction, and winding thread on a reel) with both wrists. The signals of light-emitting diode markers attached to the hand and forearm were detected by the optic receptor in the motion controller. We compared the results between both wrists and between motions with similar motion paths. Results: The parameters (range of motion, offset, coupling, and orientations of the oblique plane) for wrist motion were not significantly different between both wrists, except for radioulnar deviation for hammering and the orientation for thread winding. In each wrist, the ranges for hammering were larger than those for dart throwing. The offsets and the orientations of the oblique plane were not significantly different between circumduction and thread winding. Conclusions: The results for the parameters of dart throwing, hammering, and circumduction of our motion analysis system using the motion controller were considerably similar to those of the previous studies with three-dimensional reconstruction with computed tomography, electrogoniometer, and motion capture system. Therefore, our system may be a cost-effective and simple method for wrist motion analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.148-154
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• 2016

Video security has recently emerged as an important issue owing to CCTV video image spill accidents over the Internet. KISA recommends the use of encryption protocols for remote access through its guidelines for CCTV personal video information protection. But still, many products do not adhere to the guidelines, and those products are easily exposed to security threats, such as hacking. To solve these security vulnerabilities, this paper proposes a CCTV system that connects from remote locations, and is implemented by using secure shell (SSH) tunneling techniques. The system enhances security by transmitting encrypted data by using SSH. By using the tunneling technique, it also solves the problem of not being able to access a CCTV recorder located inside a firewall. For evaluation of the system, this paper compares various CCTV remote access schemes and security. Experimental results on the effectiveness of the system show it is possible to obtain remote access without a significant difference in transmission quality and time. Applying the method proposed in this paper, you can configure a system secure from the threats of hacking.

• Journal of Korea Multimedia Society
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• v.4 no.1
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• pp.13-28
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• 2001

In a VOD(Vide-On-Demand) system, video data are generally stored in magnetic disk array. In order to provide real-time requirement for data retrieval, video streams must be delivered continuously to the clients such that the delivery of continuous media can be guaranteed in a timely fashion. Compared to the increased performance of processors and networks, the performance of magnetic disk systems have improved only modestly. In order to improve the performance of storage system, disk array system is proposed and used. The array system improves I/O performance by placing disks in parallel and retrieving data concurrently. In this paper, two approaches are considered in order to access the video data in a VOD system, which are CTL(Constant Time Length) and CDL(Constant Data Length) access policies. Disk scheduling policies are also classified into the two categories and compared in terms of the maximum allowable video streams with different degrees of disk array synchronization, under the mixed environments in which both data access policy and disk scheduling policy are considered. Among the compared scheduling policies, LOOK was shown to have the best performance. In terms of degree of disk synchronization, more gain was achieved with large degree of synchronization. In comparisons of performance of CTL and CDL, CTL was proved to have a little superior performance in terms of number of maximum allowable streams.

• Journal of Broadcast Engineering
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• v.24 no.6
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• pp.1085-1095
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• 2019

In this paper, we perform a subjective quality assessment on low-resolution surveillance videos, which are encoded with a very low target bit-rate to use in an ultra-low band transmission system and investigate the encoding effects on the perceived video quality. The test videos are collected based on their spatial and temporal characteristics which affect the perceived quality. H.265/HEVC encoder is used to prepare the impaired sequences for three target bit-rates 20, 45, and 65 kbps and subjective quality assessment is conducted to evaluate the quality from a viewing distance of 3H. The experimental results show that the quality of encoded videos, even at target bit-rate of 45 kbps can satisfy the users. Also we compare objective image/video quality assessment methods on the proposed dataset to measure their correlation with subjective scores. The experimental results show that the existing methods poorly performed, that indicates the need for a better quality assessment method.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.105.6-105
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• 2001

Fish schools behave like a single organism and offer a considerable survival advantage. In our simulations, the fish school is well organized and behaves like a single creature depending solely on the interactions among individuals without having any director fish. This kind of system can be said as the typical one of "Complex Systems". We make clear the validity of fractal analyses to evaluate fish school movements through evaluation of both the simulated movements and the real sardine movements taken by video tape. The analyses showed that we need two kinds of fractal dimensions (D$_1$, D$_2$) to fit to the observations; the one(D$_1$) corresponds to smaller coarsening levels and D$_2$ does to larger coarsening levels. The double linear analyses in ...

• Journal of the Korea Society for Simulation
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• v.9 no.2
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• pp.51-61
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• 2000

In recent years, significant advances in computers and communication technologies have made multimedia services feasible. As a result, various queueing models and cost models on architecture and data placement for multimedia server have been proposed. However, most of these models do not evaluate dependability of systems. In the design phase of a system, simulation is an important experimental means for performance and dependability analysis. Fault injection simulation has been used in evaluation of dependability metric. In this paper, we develop fault injection simulation model to analyze dependability of parallel video servers. In addition, we evaluate reliability and MTTF(Mean Time To Failure) of systems by using the simulator.

• Journal of The Korean Association For Science Education
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• v.31 no.1
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• pp.1-13
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• 2011

The purpose of this research is to investigate ways to introduce mentoring system to support beginning and experienced teachers for their professional development. As an alternative to existing teacher training programs, we planned and implemented a mentoring system to examine its effects in developing professionalism among teachers-in-need, and those who have not met the teacher's evaluation standards. Mentoring is defined as being concerned with promoting the 'development of an individual to his/her full potential,' both professionally and personally. It is linked with professional and career development, and is somewhat characterized by an 'expert-novice' relationship. The mentoring system in science features group mentoring, where 3 prot$\'{e}$g$\'{e}$-mentor teams gathered together for instructional consulting using their videotaped classroom teaching. Through video-based discussions, teachers could share reflective experiences through collaborative investigations based on evidences revealed in classroom teaching videos. Using open-ended interviews with the teachers and video-based discussions, we extracted needs and goals of mentoring, the need of mentoring system to support beginning teachers, and the requirement of mentor quality in light of mentor's expected roles. Conclusions and recommendations related to teachers' mentoring and for the government's development of mentoring system are discussed.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.1
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• pp.32-40
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• 2009

In this paper, we proposed an reconstruction algorithm of transmitted frames from displayed image on video terminal. For image quality assessment of the video streaming in the wireless network, we need information of the image that is transmitted to the end-user's device. Generally, subjective methods are widely used to evaluate the image quality by human beings because it is difficult to extract the transmitted image from the end-user's device. This paper presents an image reconstruction algerian based on the displayed image in video terminal for the extraction of the transmitted image. In the proposed method, we acquired the displayed image on video terminal using the camera. Camera-acquired images exhibit geometric and color distortions caused by characteristics of cameras and display devices. Therefore we correct the geometric distortion by exploiting the homography and color distortion by pre-computed look-up table. The experimental results show that the proposed measurement system yields promising estimation performance in terms of PSNR of $27{\sim}28dB$. We also carried out performance evaluation of the proposed method in terms of EPSNR and the quality of the estimated images by the proposed algerian was in fairly good range of MOS test scale.

• Journal of the Korea Society of Computer and Information
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• v.14 no.3
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• pp.65-74
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• 2009

Scene change detection is pretreatment to index and search video information in video search system, and it is very important technology for overall performance. Existing scene change detection used single characteristic of pixel value difference, histogram difference, etc or mixed single characteristics that have complementary relationship. However, accuracy of those researches is very poor for special video such as infrared camera, night shooting. Therefore, this paper is proposed the method that is mixed color histogram and at algorithm for scene change detection at the specific movie. To verify the usefulness of a proposed method, we did an experiment which used color histogram only and KLT algorithm with color histogram. In result, evaluation index of proposed method is improved about 11.4% at the specific movie.

• Korean Institute of Interior Design Journal
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• v.22 no.2
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• pp.58-67
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• 2013

The methods used in this study included investigation of media facades used for landmarks in downtown areas in previous studies, visits to these areas, and recording of media facades. The changes in the colors or the size of buildings were analyzed among the recorded cases and 12 of these cases were selected for further study. The sensibility preference of the media facades was evaluated by sorting the 12 kinds of media facades, and providing them as materials to a group of 60 participants (40 undergraduate and 20 graduate students majoring in architecture and design) consisting of an equal proportion of males and females. This study addressed the following four_stage questions: 1) Five questions of recognition evaluation about media facades and the cognitive evaluation items of emotional vocabulary and color preference in each research case; 2) sensibility preference items regarding the media facade color design; and 3) design evaluation items of the media facades; 4) Video clips and still images were recorded from a middle distance at 7p.m to 11p.m. in central New York, Singapore, Seoul, and Beijing. The participants looked at the changes in colors through the video clips in each case and evaluated their preferences through 23 pairs of emotional vocabulary items using system dynamics. Construction of an emotional vocabulary followed, based on previous studies about media facades and color design. To evaluate the sensibility preference and the perceived representative colors of the media facade, this study suggests new emotional responses that depended on the color emotional vocabulary of light in the LED lighting technical evaluation methodology. A media facade with a moving change of colors, unlike a fixed landscape color design, suggests a new communication method based on architectural factors. New architectural color coordination can be presented for urban landscapes at night. Designs that factor in the pedestrians' emotional vocabulary or preference should take precedence over the use of high luminance and various colors.