• Journal of Digital Contents Society
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• v.10 no.1
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• pp.87-96
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• 2009

Digital Broadcast Service is being very popular and the delivery mechanism for digital broadcast content through IP network has progressed constantly, due to the advance of video and audio compression and network technologies. From these trends, in Korea, the commercial IPTV service starts in this year after the law related to IPTV is enacted last year. Since IPTV service, which integrates broadcast and communication services, can give an infrastructure for fusion of communication and interactive multimedia data service, IPTV service is attractive. Recently, by the advent of various wireless connection technologies and the mobile devices of high capability, Mobile IPTV, which has an advantage of not only IPTV but also mobile TV, has gained much interest. In this paper, we review a necessary ingredient for Mobile IPTV in the next generation wired/wireless convergence network environment which consists of heterogeneous wireless access networks. In addition, we propose the scheme for user mobility and service session mobility management using RTSP protocol and introduce the service gateway concept to guarantee the extension of IPTV service platform.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.123-128
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• 2020

Technology in digital video has changed the functions of the digital video field based on various platforms, including streaming, on-demand, interactive, and data-based services. The displays that provide the visual representations of these digital video contents have also been improving with various changes. There is a variety of display screen ratios currently available, with the ratio of the display screen being based on the intended purpose. This study conducted a psychophysics experiment to examine the correlation between colour properties and shape ratio based on the display screen ratio, and then analysed the results. The colours used in the experiment were visual perception-based Munsell colours, and the hue, brightness, and chroma attributes were analysed according to the shape ratio to examine colour properties. The analysis of the results of this study defined the significance of the study as basic data for future studies on colour property changes based on shape ratio, and suggested directions for future studies.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.211-215
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• 2015

It comes into the spotlight as the new Blue Ocean in which the connected car industry in which the car and mobile communication technology is convergence. All sorts of infortainments services connecting with the portable electronic device(Smart phone, tablet PC, and MP3 player) and car are rapidly grown. The Connected car emphasizes the vehicle connectivity with the concept that the car has communication with the around on a real time basis and it provides the safety and expedience to the operator and using the thing of Internet (IoT) in the car and supports the application, presently, the entertainment service including the real-time Navigation, parking assistant function, not only the remote vehicle control and management service but also Email, multimedia streaming service, SNS and with the platform. Intelligent vehicle network is studied as the kind according to MANET(Mobile Ad Hoc Network) for the safety operation of the cars of the road and improving the efficiency of the driving. The intelligent vehicle network is comprised for the driving information offering changing rapidly of the communication(V2V: Vehicle to Vehicle) between the car and the car, communication(V2I : Vehicle to Infrastructure) between the infrastructure and the car, and V2X (Vehicle to Nomadic).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.950-956
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• 2015

In this paper, a WiMedia Distributed-MAC (D-MAC) protocol is adopted for development of a seamless N-screen wireless service in Indoor and Ship Area Networks. Furthermore, to provide the OSMU (One Source Multi Use) N-screen service through P2P streaming in the seamless D-MAC protocol, a ATMT (Asynchronous Traffic Multi-hop Transmission) technology is proposed and analyzed. In this system, a WiMedia ATMT D-MAC bridge transmits control and managing information to various sensors and instruments, from a central integrated ship area network station. For this technology, a time slot allocation scheme for WiMedia asynchronous traffic and a multi-hop resource reservation scheme are combined to evaluate the performance of each scheme. From simulation results, the proposed ATMT scheme enhances performances in viewpoints of N-screen asynchronous data latency and throughput, compared to the conventional WiMedia D-MAC system.

• Convergence Security Journal
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• v.8 no.2
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• pp.41-50
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• 2008

Recently amount of traffic into the network rapidly increase since multimedia streaming services is generally adopted for application. In addition, various network management systems have been suggested for providing a stable service and QoS guarantee. It is necessary for such systems to have QoS monitoring module in order to evaluate acceptance or violation of QoS requirements by analogizing a state information of each node within network. In this paper, we suggest a network management system to evaluate QoS level between end-to-end agents and analysis traffics transmitted between them. The proposed system is implemented for the purpose of collecting network traffic information and monitoring of the view. The proposed system makes user easily understand information of QoS parameters such as throughput, delay and jitter by adopting a method of visual and numerical representation. To achieve this, we purportedly generate test packet into network for confirming acceptance or violation of QoS requirements from point of view of multimedia application service.

• Journal of Digital Convergence
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• v.18 no.4
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• pp.425-431
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• 2020

The purpose of this study is to measure the user experience of Netflix which is a representative global OTT service, Watcha and Wavve which is a representative service of Korea. Using mobile applications, qualitative research and quantitative research on user experience of OTT service were conducted with task test, in-depth interviews and surveys. As a result of the study, The usefulness and accessible of the OTT service has not shown much difference between OTT services. Rather, contents based on personal preferences has a significant impact on OTT service selection. The study found that Netflix needs to secure contents, Watcha needs to improve interface and recast categories, Wavve needs to present contents that are focused on and improve interface of main screen. The study expects to help a build a differentiate user experience in the face of growing OTT platform competition.

• Korean Journal of Social Welfare
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• v.40
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• pp.191-225
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• 2000

The purpose of this study is to formulate the way of the feminist strategy in Germany which is to change in the process of the globalization in the economic relations. The radical feminism which is the main streaming of german feminism shows a little interest in the role of the german welfare state (social state) to improve the quality of life of women. The german welfare state is, as the feminism says, only a instrument of patriarchy to perpetuate the domination of men over women. The german welfare state has played, but, an important role for the individualization of the relation of women's life which is the first condition for the emancipation of women from the patriarchal domination. That is a result of the interaction between the german welfare state and feminism. The role of the german welfare state for the interest of women is now challenged by the globalization of the economic relations which tries to reduce the standard of social services. The greatest victim of this process is women. Therefore it is necessary for the german feminism to think over the way of his strategy in relation to the german welfare state. The content of this study is as follows: First, the historical background of the german feminism explains how the radical feminism has become the mainstreaming of the german feminism. Seconds, the feminist strategy which rejects the role of the german welfare state for the interest of women has its own limits. Third, the german welfare state has not only developed the ideology of breadwinner but also contributed to the beginning of independent life of woman who were under the control of man. Fourth, the german welfare state is challenged by the economic globalization and being changed by the economic globalization. Fifth, therefore, the feminism has to concentrate to develop a strategy which accepts the limit and the possibility of german welfare state.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2B
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• pp.137-145
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• 2006

In this paper, we propose a multicast P2Patching technique in the application layer. The P2Patching technique serves VOD stream effectively with Patching in P2P environment. The P2Patching provides multicast tree construction technique that reduces the server load and minimizes the start delay with extended multicast technique. And we provide a fast recovery technique by tree failure and dynamic buffering scheme that guarantees the continuous streaming by frequent tree disconnections. Comparing the method with that of $P2Cast^{[12]}$, we obtained the better performance by our scheme in terms of average join count, service rejection probability, tree recovery failure and buffer starvation. The average about 16$\%$ of the improvement is shown by the simulation. Most of all, the performance of buffer starvation and average join count shows a significant improvement than that of P2Cast.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.460-475
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• 2016

The existing Proxy Mobile IPv6 suffers from a long handover latency which in turn causes significant packet loss that is unacceptable for seamless realtime services such as multimedia streaming. This paper proposes an OpenFlow-enabled proxy mobile IPv6 (OF-PMIPv6) in which the control of access gateways is centralized at an OpenFlow controller of a foreign network. The proposed OF-PMIPv6 separates the control path from the data path by performing the mobility control at the controller, whereas the data path remains direct between a mobile access gateway and a local mobility anchor in an IP tunnel form. A group of simple OpenFlow-enabled access gateways performs link-layer control and monitoring activities to support a comprehensive mobility of mobile nodes, and communicates with the controller through the standard OpenFlow protocol. The controller performs network-layer mobility control on behalf of mobile access gateways and communicates with the local mobility anchor in the Proxy Mobile IPv6 domain. Benefiting from the centralized view and information, the controller caches the authentication and configuration information and reuses it to significantly reduce the handover latency. An analytical analysis of the proposed OF-PMIPv6 reactive and proactive handover schemes shows 43% and 121% reduction in the handover latency, respectively, for highly utilized network. The results gathered from the OF-PMIPv6 testbed suggest similar performance improvements.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.527-535
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• 2004

Handling mixed workload in digital set-top box or streaming server becomes an important issue as integrated file system gets momentum as the choice for the next generation file system. The next generation file system is required to handle real-time audio/video playback while being able to handle text requests such as web page, image file, etc. Legacy file system provides only best effort I/O service and thus cannot properly support the QoS of soft real-time I/O. In this paper, we would like to present our experience in developing the file system which fan guarantee the QoS of multimedia stream. We classify all application I/O requests into two category: periodic I/O and sporadic I/O. The QoS requirement of multimedia stream could be guaranteed by giving a higher priority to periodic requests than sporadic requests. The proto-type file system(Qosfs) is developed on Linux Operating System.