• International Journal of Contents
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• v.14 no.1
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• pp.18-27
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• 2018

The objective of this study was to derive approximate closed-form error rates for M-ary burst symbol transmission (MBST) of dual-hop adaptive decode-and-forward (ADF) cooperative relay systems over quasi-static Rayleigh fading channels. Within a burst, there are pilot symbols and data symbols. Pilot symbols are used for channel estimation schemes and each relay node's transmission mode selection schemes. At first, our focus was on ADF relay systems' error-events at relay nodes. Each event's occurrence probability and probability density function (PDF) were then derived. With error-event based approach, we derived a tractable form of PDF for combined signal-to-noise ratio (SNR). Averaged error rates were then derived as approximate expressions for arbitrary link SNR with different modulation orders and numbers of relays. Its accuracy was verified by comparison with simulation results.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.296-301
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• 2004

The Wireless Sensor Network is technology that makes possible utilize the information collected from rescue, the agricultural and livestock management system, and the home automation system by using an ultra-small sized, ultra-lightweight sensor module. This study proposes the routing protocol with directional nature that can improve the utilization by higher energy efficiency and reliability than those of existing studies on data transmission, and we also analyze the current studies, make a comparison of them in performance.

• The Journal of the Korea Contents Association
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• v.6 no.2
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• pp.9-16
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• 2006

This paper proposes a scheduling algorithm for efficiently processing multimedia pakcet services in OFDMA physical system of the future broadband wireless access networks. The scheduling algorithm uses wireless channel state estimation, and allocates transmission rates after deciding transmission ordering based on class and priority policy. As the result, the proposed scheduling algorithm offers maximum throughput and minimum jitter for realtime services, and fairness for non-realtime services. In simulation study, the proposed algorithm proves superior performances than traditional round robin method.

• Journal of Digital Contents Society
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• v.5 no.3
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• pp.171-175
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• 2004

In this paper, We applied CCI canceller to remove multi-user interference in co-channel environment and improved performance of TH PPM UWB-IR system. As a result, We could get reception performance that data transmission of high speed is available in small reception power applying CCI canceller. Also, We could get permission available channel capacity to maximum access number 40 in high speed transmission environment more than 100Mbps.

• International Journal of Contents
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• v.14 no.4
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• pp.30-38
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• 2018

Recently, HTTP Adaptive Streaming(HAS), a video streaming service over the HTTP based web platform has become common. The use of HAS service in mobile communication devices such as mobile phones and tablet PCs is rapidly expanding. This paper addresses ways to improve the quality of HAS service by enhancing the terms of viewer satisfaction. HAS systems have several internal operational processes, which can affect viewer satisfaction. Such processes include, the quality determination for the next video chunk, the TCP connections-setup procedure and the congestion control operation of the TCP. This paper proposes a transmission scheme to improve the HAS quality services over mobile web. The proposed scheme takes into consideration the past implicit communication state of the receiver's playback buffer occupancy. The results of these experiments indicate that the proposed scheme can improve the quality of HAS service from the mobile viewer's point of view.

• The Journal of the Korea Contents Association
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• v.14 no.10
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• pp.315-329
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• 2014

The purpose of this study is to examine a direction for contents choice and transmission strategies of radio literature reading programs. For this, 129 picturebook contents used for EBS program of "children books for adults" in recent 6 months were collected and analyzed quantitatively and qualitatively based on Nicholajeva's societal and aesthetic approach. In terms of external literary elements, there were unequal distribution of published period, nation, company and genre. In terms of literary inner factors, they were excellently reflecting the stream and the tendency of modern children literature. Finally, in the process of turning visual texts into auditory texts, the program used diverse auditory transmission strategies. Based on these results, it is suggested that this program need to take into account reforming the contents selection practice to provide abundant literary experience for listeners and sophisticating the transmission effects adapted for a digital era.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.33-46
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• 2019

The purpose of this study is to analyze how China, which is the largest consumption area of Hallyu broadcasting contents but the most illegal copy market infringe the rights of domestic broadcasters and what of the policy of regulatory authority in this illegal market. To this end, this study investigate the most common types of paths and methods of copyright infringement in the Internet and mobile multi-platform environments, and investigated how broadcasters responded to them with in-depth interviews. As a result of research, the most frequent type of infringement of rights of reproduction were to use links with web and apps and TV pads. In this regard, it was not easy to solve the problem of illegal copy in China in the way that domestic companies responded to individually, and it was very rare that the lawsuit was filed. In the future, the government will need to provide side support for Korean Wave broadcasting contents through steady monitoring as well as market research for eradication of illegal copy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.4
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• pp.581-587
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• 2021

Real-time video streaming scheme for multimedia content delivery and remote conference services is one of technologies that are significantly sensitive to data transmission delay. Recently, because of COVID-19, real-time video streaming contents for the services are significantly increased such as personal broadcasting and remote school class. In order to support the services, there is a growing emphasis on low transmission delay and secure content delivery, respectively. Therefore, our research proposed a packet aggregation algorithm to reduce the transmission delay of selectively encrypted video transmission for real-time video streaming services. Through the application of the proposed algorithm, the selectively encrypted video framework can control the amount of MPEG-2 TS packets for low latency transmission with a consideration of packet priorities. Evaluation results on testbed show that the application of the proposed algorithm to the video framework can reduce approximately 11% of the transmission delay for high and low resolution video.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.02a
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• pp.457-463
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• 2000

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2C
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• pp.283-290
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• 2004

With the development of Web technologies, the demand for multimedia contents and network bandwidth is increasing explosively. In this situation, Caching, P2P and CDN are using for fast transmission with low traffic. In this research, we designed and implemented a redirection system for best replica selection where contents are distributed to multiple replicated web servers. This redirection system selects a close and least loaded replica and redirect a client's request to the replica. As a result, this system improved user-perceived performance. It is expected that this redirection system will contribute to the faster and more stable transmission of massive multimedia contents.