• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8A
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• pp.879-888
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• 2004

In this paper, we propose a real time QoS(Quality of Service) guaranteed transmission mechanism for MPEG video traffic at the congested node in IP based networks. Recent spread of the Internet has increased the demands of a real time multimedia service of the quality, Because the type of Internet services can, however, offer the best effort delivery strategies, it is difficult to treat all the types of traffic with differential COS (Class of Service). Most of all, the hierarchical coding method of MPEG data utilizes the reference frame for the motion prediction. The loss of the reference frames makes QoS of the video traffic degraded because the reference frame bit error causes the consecutive packet loss. Therefore we have studied the real time QoS guaranteed mechanism for video traffic by analyzing the previous methods. Computer simulation results show that the proposed scheme has better performance than the previous one.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.12 no.3
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• pp.171-190
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• 2008

With growing applications of wireless video streaming, an efficient video traffic model featuring modern high-compression techniques is more desirable than ever, because the wireless channel bandwidths are ever limited and time-varying. We propose a modeling and analysis method for video traffic by a class of stochastic processes, which we call '$GEO^Y/G/{\infty}$ input processes'. We model video traffic by $GEO^Y/G/{\infty}$ input process with gamma-distributed batch sizes Y and Weibull-like autocorrelation function. Using four real-encoded, full-length video traces including action movies, a drama, and an animation, we evaluate our modeling performance against existing model, transformed-M/G/${\infty}$ input process, which is one of most recently proposed video modeling methods in the literature. Our proposed $GEO^Y/G/{\infty}$ model is observed to consistently provide conservative performance predictions, in terms of packet loss ratio, within acceptable error at various traffic loads of interest in practical multimedia streaming systems, while the existing transformed-M/G/${\infty}$ fails. For real-time implementation of our model, we analyze G/D/1/K queueing systems with $GEO^Y/G/{\infty}$ input process to upper estimate the packet loss probabilities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.893-901
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• 2013

This paper suggests a method of developing live media streaming service through Linux server system on android system environment. The android application constructed in the experiment is able to record media while sending it to Linux server. Generated real time media data is send to linux server through Multipart Request class of Apache Tomcat server constructed on Linux system. Also in this research, by utilizing Android video player and media player class, development of android application structures was accomplished, which has methods of; playing live media stream data on video server, or playing live media stream data while saving stream data in cache. The structure and function of suggested system and application is confirmed by series of experiments.

• Knowledge Management Research
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• v.21 no.2
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• pp.119-135
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• 2020

Owing to pandemic (COVID-19), the traditional face-to-face education method has been changed to the non-face-to-face real-time online education methods. Using a real time-based video conference system, synchronous education can be adopted by face-to-face class easily. Specially, it is very important to minimize the difference in learning effects between face-to-face and non-face-to-face in Entrepreneurship education. In this study, in order to derive the factors that affect the satisfaction of learners in synchronous online education, authors collected data from learners taking a synchronous entrepreneurship course. Through previous research, learned the reality of education and the composition of lessons. Spatiotemporal effectiveness, mentor ability, and educational environment influence learning satisfaction. PLS-SEM results revealed that it was confirmed that only spatiotemporal effects affect learner satisfaction. However, the education environment (fluent operation and convenience of function use of real-time based online conference system) effect teaching presence, class structure, and spatiotemporal effects. Through this research, we hope to provide theoretical and practical support for developing effective teacher activities, proper lesson structure, convenient function of the conference system, and learner-centered online learning environment when developing synchronous online classes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.57-63
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• 2015

There are increasing demands for the transmission of high speed and non-compressed video informations. The video data usually compressed before transmission for reducing the data. And the received data uncompressed at a receiver, consequently the processing delay is unavoided. In this paper, we implement a 60 GHz band wireless transmission system for real time multimedia contents transmission, and successfully transmit the full HD class uncompressed video information at 4 Gbps with 20 m apart. Hence the non-compressed video data from a remote camera or a smart phone can be transmitted and displayed in a large screen in real time via the developed transceiver system.

• Journal of Korean Physical Therapy Science
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• v.28 no.3
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• pp.1-10
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• 2021

Background: The purpose of this study is to investigate the effect of the online team project based learning on problem-solving, cooperative self-efficacy, and cooperative self-regulation of college students. Design: Single group pre-post design. Methods: The online team project based learning was conducted for a total of 92 college students for 8 weeks. A survey was conducted on problem-solving ability, cooperative self-efficacy, and cooperative self-regulation. In the online team project-based class, two projects were performed. It consists of video lectures and real-time video conferencing. Through the real-time video conference, the project was carried out based on discussion among learners and feedback was provided. Results: There was a significant difference in the change in problem-solving ability compared to before learning (p<0.05). As a result of the evaluation of cooperative self-efficacy, there was a significant difference (p<0.05). There was a significant differences in cooperative self-regulation compared to before learning (p<0.05). Conclusion: The online team project-based learning are effective in improving learners' problem-solving ability, cooperative self-efficacy, and cooperative self-regulation.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.341-348
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• 2022

Formulaic sequences are continuous or discontinuous series of words that are seemingly treated like single units. Formulaic sequences play a key role in language development, and formulaic sequences acquisition determines the success or failure of language development. This study proposes a reading aloud activity as a way for international students to learn formulaic sequences. A class focused on reading aloud was conducted with 41 international students taking a general English course at a university in Seoul. For 15 weeks, video lectures and real-time Zoom classes were conducted in parallel. The animated film Frozen was used as course material. In the video lectures, the teacher interpreted the movie script in easy Korean and read aloud formulaic sequences. Students were tasked with reading the sentences with formulaic sequences aloud, recording themselves reading aloud, and submitting their recordings. During real-time class meetings, students performed the activity of reading aloud the formulaic sequences they had studied in the video lectures. There was a significant increase in the interpretation and sentence writing of formulaic sequences in participants' post-evaluation compared to the pre-evaluation. Through the study's survey, students exhibited positive views in the affective domains.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.11
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• pp.795-800
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• 2013

Early detection of oestrus in Korean cows is one of the important issues in maximizing the economic benefit. Although various methods have been proposed, we still need to improve the performance of the oestrus detection system. In this paper, we propose a video surveillance system which can detect unusual behavior of multiple cows including the mounting activity. The unusual behavior detection is to detect the dangerous or abnormal situations of cows in video coming in real time from a surveillance camera promptly and correctly. The prototype system for unusual behavior detection gets an input video from a fixed location camera, and uses the motion vector to represent the motion information of cows in video, and finally selects a SVDD (one of the most well-known types of one-class SVM) as a detector by reinterpreting the unusual behavior into an one class decision problem from the practical points of view. The experimental results with the videos obtained from a farm located in Jinju illustrate the efficiency of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.288-303
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• 2009

In the near future it is foreseen that a genuine multimedia service over the WiMAX system is provided in a worldwide manner by exploiting the QoS technologies introduced in the wireless and wired broadband network. In this work we propose a pricing scheme for the multimedia service over the generic WiMAX system that supports a full QoS functionality. We assume real-time services such as the voice and video as well as the nonreal-time service such as the conventional high-speed data, and we propose a pricing and charging scheme for those services by investigating the inherent characteristics of those services and the multiple-class of QoS-service provided to them. After that we propose a method to compute expected revenue that is obtained from the WiMAX system by using an analytic method to estimate the usage of the bandwidth resources for the different class of services. Via numerical experiment, we verify the implication of the work.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.473-494
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• 2020

To provide a guaranteed Quality of Service (QoS) to real-time traffic in High-Speed Downlink Packet Access (HSDPA) core network, we proposed an enhanced mechanism. For an enhanced QoS, a Class-Based Low Latency Fair Queueing (CBLLFQ) packet scheduling algorithm is introduced in this work. Packet classification, metering, queuing, and scheduling using differentiated services (DiffServ) environment was the points in focus. To classify different types of real-time voice and multimedia traffic, the QoS provisioning mechanisms use different DiffServ code points (DSCP).The proposed algorithm is based on traffic classes which efficiently require the guarantee of services and specified level of fairness. In CBLLFQ, a mapping criterion and an efficient queuing mechanism for voice, video and other traffic in separate queues are used. It is proved, that the algorithm enhances the throughput and fairness along with a reduction in the delay and packet loss factors for smooth and worst traffic conditions. The results calculated through simulation show that the proposed calculations meet the QoS prerequisites efficiently.