• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.7
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• pp.728-736
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• 2014

Due to the recent development of mobile wireless telecommunication, RRHs(Remote Radio Heads) are widely being utilized to expand the cell coverage. Wire-link, an existing connection between DU(Digital Unit) and RRH through fiber cables, is considered to have limitations in relation to cost for a wide range of applications. This paper focuses on replacing the wire-link by wireless transmission using millimeter-wave, and implementing cellular network system through RRH from a remote location. After an influence element analysis on millimeter-wave wireless link transmissions, a comparative analysis between wireless link and an existing fiber link method will be made by utilizing currently commercialized LTE(Long Term Evolution), to prove the compatibility of millimeter-wave wireless link RRH method in replacing fiber link method without a significant decline in data transmission performance.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.1
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• pp.44-55
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• 2008

Catalyzed by the recent development of space technology, various kinds of spacecrafts were launched and utilized with purposes in many developed countries. In case of emergency such as natural disasters, proper satellite images are required in order to help to mitigate and assess the effects of disasters on human life and property. Since there are limitations for a nation to single-handedly operate a satellite and fulfill complete demands, a development need of international cooperation organization to share satellite images among the member countries has risen. In this paper, preestablished four international organizations' background, objectives, and operating system, and their principal characteristics were analyzed and compared. Especially, the paper has focused on the analysis of on-going operating procedures and its cases for International Charter, UN SPIDER's development of local supporting network to support NFP, establishment of Web-GIS by Sentinel Asia under the goal of 'Digital Asia', and the utilization of GEO that is widely applied in natural disaster fields.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.297-310
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• 2013

In this paper, we present a model-based video bit rate estimation scheme for reducing the bit rate while maintaining a subjective quality in many video streaming services limited by network bandwidth, such as IPTV services. First, we extract major parameters which serve as an indirect measurement of frame's bits. Using those parameters, the proposed bit rate estimation scheme can extract candidate frames. Finally, the bit rate of each segment is estimated by statistical analysis and a mathematical model based on a given target quality. In experimental results, we show that the proposed scheme can reduce the bit rate on average by 43% in low-complexity video while maintaining the subjective quality. To find the appropriate bit rate based on video contents, the proposed schemes can estimate the bit rate with neither the repeated full encoding nor subjective quality test. On average, the bit rate can be automatically estimated by encoding the candidate frames of 4%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8C
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• pp.777-785
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• 2006

H.264 is the prominent video coding standard in various applications such as real-time video streaming and digital multimedia broadcasting, since it provides enhanced compression performance, error resilience tools, and network adaptation. Since compressed video stream is vulnerable to packet loss, error resilience and error concealment(EC) tools are essential for the transmission of video over the Internet. In this paper, we first propose a simple temporal EC method that improves the EC performance for intra-frame in H.264 when the amount of motion is relatively small. Then we propose a new hybrid EC method for intra-frame in H.264, which combines the spatial EC and temporal EC adaptively. The simulations are performed in packet-lossy environments, and the proposed hybrid EC method shows about 0.5-4dB PSNR improvement compared to the conventional spatial EC method that is used for intra-frame in H.264.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.611-614
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• 2007

Due to illegal copying and distribution via the internet, the digital media that have been introduced create certain intellectual property issues. Because of this, several intellectual property groups have been created to create and maintain Digital Rights Management systems (DRM), in order to crack down on illegal and unauthorized copying. However, these systems are often created by many different companies, which leads to problems of interoperability. Despite attempts to regulate DRM systems, including the MPEG group's Intellectual Property Management and Protection" system, the system is still struggling to maintain some sort of interoperability between differing protocols. In this paper, we designed and implemented a DRM system with Gstreamer, following the DMP.

• Journal of KIISE:Software and Applications
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• v.31 no.10
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• pp.1320-1331
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• 2004

A video adaptation system translates the source video stream into appropriate video stream while satisfying the network and client constraints and maximizing the video quality as much as possible. This paper proposes a semi-dynamic video adaptation scheme, in which several intermediate video streams and the information for the measuring of video quality are generated statically. The intermediate video streams are generated by reducing the resolution of the video stream by a power of two several times, and they are stored as the intermediate video streams on the video server. The statically generated information for the input video stream consists of the degrees of smoothness for each frame rate and the degree of frame definition for each pixel bit rate. It helps to dynamically generate the target video stream according to the client's QoS at run-time as quickly as possible. Experimental result shows that the proposed adaptation scheme can generate the target video stream about thirty times faster while keeping the quality degradation as less than 2% comparing to the target video stream that is totally dynamically generated, although the extra storages for the intermediate video streams are required.

• Journal of KIISE:Information Networking
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• v.33 no.2
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• pp.139-148
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• 2006

Recently with the advancement of local wireless communication technologies, digital trends of audio contents and devices are paving the way for new experiences to network-based audio streaming services. In this paper, we present the Wireless Audio Sharing (WASH) technology over Bluetooth and Wireless Local Area Network (WLAN). WASH system provides an audio sharing mechanism over multiple users and also provides stereo audio streaming between Bluetooth-enabled devices and Universal Plug and Play (UPnP) media devices connected to wired/wireless LANs. To achieve these, we extended the Bluetooth audio distribution profile and combined the extended profile with the UPnP AV architecture. With the implementation of this WASH technology, we show some experimental results of the stereo audio streaming in a real environment.

• The Journal of the Korea Contents Association
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• v.6 no.3
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• pp.154-162
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• 2006

The weight of the story in the field of animation that is developed in digital and network is increasing gradually. It occurs not only in animation but several related fields. It shows the potential and needs of animation education based on the story. In this research several literary studies were conducted to identify essential factors of the story-telling in the animation story board production. To visualize the contents in details for the first time, we tried to find the intention of the producer of the animation story board and the work's depth by researching the role and production process in animation story board which applies all of the productions. The important visual factors in producing the animation will be the subjects of the research in near future, and the studies as the important communication art will be carried out by developing the visual and creativeness of the expressions.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.3
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• pp.164-179
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• 2013

Ulaanbaatar city, the capital of Mongolia and the center of Mongolian economy, increasingly needs to have a long-term urban planning and a system to impose a tax on land effectively as insufficient development of land and the moving of nomad into urban areas increases during its rapid growth. Therefore, Mongolian government has to prepare a land management system which provides the infrastructure to improve work efficiency and service quality by integrating digitalized data about land and main facilities and sharing data between related departments. This research analyzed the environment to operate the existing land management system and working environment and redesigned database. Furthermore, it integrated all the existing systems, configured service network, and made working environment for land registration, land permission, land payment management to be processed online. With this, it provides the foundation to improve quality of people's life through the preparation of long term urban planning, clean tax administration of real estate, and reconsideration of efficiency about urban infrastructure investment.

• Journal of the Korean Society for information Management
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• v.31 no.4
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• pp.69-102
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• 2014

In this study, we propose an approach of building a portal site that can offer integrated services for textbook through special libraries For this purpose, we analyzed previous related studies and investigated textbook portal construction sites domestically and abroad. Based on this research, we developed survey questions and conducted a survey targeting users of textbook libraries. As a result, the following projects are required for creating a textbook library: a comprehensive list of textbooks and other content construction, digitization projects of library holdings, collection and delivery of various textbook-related reference books, building a textbook database by topic, collecting and providing textbook-related research publications, a cooperation network with textbook-related organizations, and active promotion of portal sites.