• Journal of Digital Convergence
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• v.17 no.6
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• pp.219-227
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• 2019

This study aims to examine Blockchain research trend using bibliometrics-based network analysis. The data were collected from WoS, Scopus, Korea Citation Index and National science & Technology Information Service, from 2009 to 2018. As results, the number of publications has started increasing rapidly from 2017 and it showed the initial stage of formation of coauthor network. Words often used in the title of the publications were related to application development, controversy and technology development. In addition, the majority of domestic papers are in the subject of social science, while international papers tend to focus on engineering issues. The results of the temporal analysis show that Korean researchers' block chain 3.0 started in 2017 and are rapidly increasing in 2018. The number of citations was associated with publication year in a statistically signifiant way. By examining these research trends, we hope that this paper can be a useful basis for the development of blockchain. Future research is expected to reveal more clearly the knowledge structure and characteristics of blockchain around the world.

• Journal of the Korea Society of Computer and Information
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• v.11 no.6 s.44
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• pp.227-235
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• 2006

MPEG-21's digital item adaptation technology becomes a new way for universal multimedia access. It needs transcoder to change media resource's format and so on according to delivery context Then, the use of heavy transcoder with various transcoding functions integrated into one altogether is so complicated and difficult in supporting universal multimedia access. Unit transcoder Is useful is to resolve this question, in which a transcoder has only one transcoding function. This requires considering how to compose a set of unit transcoders. Thus, given a set for end-to-end different service quality pairs according to the character of application as defined by user, this study suggests how to compose complete unit transcoders that can always create one and more transcoding path(s) for each pair in the set. This method has a question of creating too many transcoding paths for each pair or end-to-end different service quality. Thus, this study also suggests the algorithm that generates minimum unit transcoder sets to support multimedia adaptation with minimum unit transcoder. The algorithm suggested was implemented into multimedia stream engine, and this paper describes the results of experiment for this algorithm.

• Journal of Information Management
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• v.22 no.1
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• pp.21-38
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• 1991

Optical laser discs are expected with it's roles as a new media to manage vast materials. Optical disc, optical videodisc, CD-ROM began to emerge from laboratories in the early seventies. By the passage of time, each of optical disc became to take particular significances to libraries. Also, each of optical discs were developed and disseminated with different objectives each other in information market. Recently, the storage capacity of CD-ROM disc began to lead to extensive consumer in on-line database market, and became an economic reality, because it's storage capacity is considerable over 600MB on a 12cm disc and it's system could be built in rather with cheap equipment. In my article, the optical disc retrieval system in libraries was investigated among various features in each kinds of libraries historically. And many efforts were attempted to present the possibilities which can apply on optical disc system. I relized that CD-ROM could be utilized at cataloging service and bibliographic database than other technical service. At the same time, I recognized that optical disc system could be used to retrieve all kinds of graphic information and digital data with retrieval system development. Therefore the tendancy of information management in future will be foreward to the way which apply optical discs on base of on-line and include all of graphic and digital database by using the developed retrieval software.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.10
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• pp.1031-1041
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• 2009

A small microstrip monopole antenna for macro-micro frequency tuning over multiple bands is presented. The meander-shape antenna is fabricated on a conventional printed circuit board(FR-4, $\varepsilon_r=4.4$ and tan $\delta=0.02$). The antenna operates over WiBro(2.3~2.4 GHz) and WLAN a/b(2.4~2.5 GHz/5.15~5.35 GHz) service bands with an essentially constant antenna gain within each service band. Two diodes, a PIN diode and a varactor, are embedded into the antenna for frequency reconfiguration. The PIN diode is used for frequency switching(macro-tuning) between 2 GHz and 5 GHz bands while the varactor is used for frequency tuning(micro-tuning) within the service bands, 2.3~2.5 GHz and 5.15~5.35 GHz. Unwanted resonances between the two frequency bands(2 GHz and 5 GHz) are suppressed by filling up the gaps between the meander lines. The antenna gain is essentially constant and higher than 2 dBi within each service band. The measured performance of the proposed antenna system suggests the macro-micro frequency tuning techniques be useful in reconfigurable wireless communication systems.

• Journal of Broadcast Engineering
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• v.17 no.5
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• pp.827-837
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• 2012

As broadcasting environments change rapidly to digital, user requirements for next-generation broadcasting service which surpass current HDTV service become bigger and bigger. The next-generation broadcasting service progress from 2D to 3D, from HD to UHD and from 5.1ch audio to more than 10ch audio for high quality realistic broadcasting service. In this paper, we propose 10.2ch based multichannel audio reproduction system for UHDTV. The 10.2ch-based audio reproduction system add two side loudspeakers to enhance the surround sound localization effect and add two height and one ceiling loudspeakers to enhance the elevation localization effect. To evaluate the proposed system, we used APM(Auditory Process Model) for objective localization test and conducted subjective localization test. As a result of objective/subjective localization test, the proposed system shows the statistically same performance compare with 22.2ch audio system and shows the significantly better performance compared with 5.1ch audio system.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.92-100
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• 2010

Due to the development of digital appliance, role of TV causes both-way by introducing IPTV, and SNS service causes big change of watching environment and residence environment. There are good conditions on the role of integrated control because it is arranged in the living room which secures movement most effectively and because family members can easily use, and the degree of use is high. Therefore, we infer user's needs by analyzing user scenario and current role of TV in home network environment. Primarily, we collect surveys of development scenario and technology which companies suggest TV applied by home network service, and secondly, we comparatively study scenario which the companies mentioned above suggest through observing user scenario, and study the role of IPTV in the future through actual scenario-based experiment by ethnography. After analyzing user scenario through case study and experiment, there are integrated device studies mainly in company study because it can be made up inside home, security and entertainment. On the other hand, there are patterns of user behavior by scenario experiment mainly in auto-tainment, security, and it showed that it is insufficient for interaction between TV and home media peripheral. Through this paper, we analyze context of home user, and based on this, we could suggest effective use of service development. Also after analyzing user form, we could know it also should be considered of ratio between activity inside home and activity outside home.

• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.310-339
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• 2015

In this paper, the possibility of a terrestrial fixed 4K UHD (Ultra High Definition) and mobile HD (High Definition) convergence broadcasting service through a single channel employing the FEF (Future Extension Frame) multiplexing technique in DVB (Digital Video Broadcasting)-T2 (Second Generation Terrestrial) systems is examined. The performance of such a service is also investigated. FEF multiplexing technology can be used to adjust the FFT (fast Fourier transform) and CP (cyclic prefix) size for each layer, whereas M-PLP (Multiple-Physical Layer Pipe) multiplexing technology in DVB-T2 systems cannot. The convergence broadcasting service scenario, which can provide fixed 4K UHD and mobile HD broadcasting through a single terrestrial channel, is described, and transmission requirements of the SHVC (Scalable High Efficiency Video Coding) technique are predicted. A convergence broadcasting transmission system structure is described by employing FEF and transmission technologies in DVB-T2 systems. Optimized transmission parameters are drawn to transmit 4K UHD and HD convergence broadcasting by employing a convergence broadcasting transmission structure, and the reception performance of the optimized transmission parameters under AWGN (additive white Gaussian noise), static Brazil-D, and time-varying TU (Typical Urban)-6 channels is examined using computer simulations to find the TOV (threshold of visibility). From the results, for the 6 and 8 MHz bandwidths, reliable reception of both fixed 4K UHD and mobile HD layer data can be achieved under a static fixed and very fast fading multipath channel.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.4
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• pp.414-420
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• 2018

The digital convergence looking for new ways to engage visitors by superimposing virtual content on projection over the real world captured media contents. This paper propose the Light ID based interactive 3D immersive exhibition things view using HMD AR technology. This approach does not required to add any additional infrastructure to be built-in to enable service and uses the installed Lighting or displays devices in the exhibit area. In this approach, the Light ID can be used as a Location Identifier and communication medium to access the content unlike the QR Tag which supports provide the download information through web interface. This utilize the advantages of camera based optical wireless communication (OWC) to receive the media content on smart device to deliver immersive 3D content visualization using AR. The proposed exhibition method is emulated on GALAXY S8 smart phone and the visual performance is evaluated for Jeonju Hanok Village. The experimental results shows that the proposed method can give immersive 3D view for exhibit things in real-time.

• Journal of Broadcast Engineering
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• v.9 no.4 s.25
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• pp.305-321
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• 2004

With the advent of the digital broadcasting, the audiences can access a large number of TV programs and their information through the multiple channels on various media devices. The access to a large number of TV programs can support a user for many chances with which he/she can sort and select the best one of them. However, the information overload on the user inevitably requires much effort with a lot of patience for finding his/her favorite programs. Therefore, it is useful to provide the persona1ized broadcasting service which assists the user to automatically find his/her favorite programs. As the growing requirements of the TV personalization, we introduce our automatic user preference learning algorithm which 1) analyzes a user's usage history on TV program contents: 2) extracts the user's watching pattern depending on a specific time and day and shows our automatic TV program recommendation system using MPEG-7 MDS (Multimedia Description Scheme: ISO/IEC 15938-5) and 3) automatically calculates the user's preference. For our experimental results, we have used TV audiences' watching history with the ages, genders and viewing times obtained from AC Nielson Korea. From our experimental results, we observed that our proposed algorithm of the automatic user preference learning algorithm based on the Bayesian network can effectively learn the user's preferences accordingly during the course of TV watching periods.

• Journal of Broadcast Engineering
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• v.19 no.3
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• pp.342-354
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• 2014

This paper deals with digital watermarking methods to protect ownership of image with targeting the ultra-high multi-view or free-view image service in which an arbitrary viewpoint image should be rendered at the user side. The main purpose of it is not to propose a superior method to the previous methods but to show how difficult to construct a watermarking scheme to overcome the viewpoint translation attack. Therefore we target the images with various attacks including viewpoint translation. This paper first shows how high the error rate of the extracted watermark data from viewpoint-translated image by basic schemes of the method using 2DDCT(2D discrete cosine transform) and the one using 2DDWT(2D discrete wavelet transform), which are for 2D image. Because the difficulty in watermarking for the viewpoint-translated image comes from the fact that we don't know the translated viewpoint, we propose a scheme to find the translated viewpoint, which uses the image and the corresponding depth information at the original viewpoint. This method is used to construct the two non-blind watermarking methods to be proposed. They are used to show that recovery of the viewpoint affect a great deal of the error rate of the extracted watermark. Also by comparing the performances of the proposed methods and the previous ones, we show that the proposed ones are better in invisibility and robustness, even if they are non-blind.