• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1B
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• pp.117-124
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• 2004

With MPEG-4 3D mesh coding(3DMC), the problem of the need of a wide bandwidth can be solved to store and transmit 3D information because of its high compression rate. And to realize the 3D information service with broadcasting or internet, one needs to transmit not only the 3D contents but also the 3D player. Therefore, in this paper we implement a 3D player based on MPEG-4 using a java language. A well-known java language employed in this paper provides the player with a wider range of applications, for example, when the O/S or the platform are different, due to its properties of scalability and universality. The implemented player which has functions (translation, rotation, etc) that can manipulate contents decodes the 3D contents and displays them. In addition, the player has a network function that receives a 3D content from the server. This paper explains the architecture and characteristics of the player and shows its simulation results.

• Journal of Satellite, Information and Communications
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• v.4 no.2
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• pp.28-33
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• 2009

In this paper, we evaluate the performance of various diversity techniques which can contribute to provide efficient multimedia broadcasting services via hybrid/integrated satellite and terrestrial network. Space-time coding can achieve the diversity gain in a multi-path environment without additional bandwidth requirement. Recent study results reported that satellite systems can achieve high diversity gains by appropriate utilization of STC and/or forward error correction. Based on these previous study results, we present various cooperative diversity techniques by combing STC and rate compatible turbo codes in order to realize the transmit diversity for the mobile satellite system. The satellite and several terrestrial repeaters operate in unison to send the encoded signals, so that receiver may realize diversity gain. The results demonstrated in this paper can be utilized in future system implementation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.119-124
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• 2010

디지털 제작, 압축 기술의 발전, 유무선 인터넷 보급 확산, 다양한 전송 및 서비스 플랫폼의 등장, 전송 기술의 광대역화, 단말 기술의 발전, 라이프스타일 변화와 킬러 서비스 등장으로 미디어 시장은 급속도로 발전하고 있다. 지상파 방송은 아날로그에서 디지털로 전환하고 있으며, 고화질, 다채널, 모바일, 3D 서비스를 제공하거나 제공할 예정에 있다. 현재 디지털 TV는 아날로그 TV와 동시 방송 형태로 제공되고 있지만 2012년말 디지털 TV로 완전한 전환을 앞두고 있으며, 모바일 TV인 DMB는 2005년말 본방송을 시작하여 전국 서비스를 제공하고 방송 커버리지를 확장하고 있다. FM과 AM의 디지털화를 위한 디지털 오디오 방송도 방식 선정을 위한 절차가 진행 중이다. 전파는 송신소에서 단말까지 전송되는 도중 신호레벨 감쇠, 페이딩, 왜곡, 잡음 유입 등을 겪게 된다. 양질의 지상파 방송을 제공하기 위해서는 전파가 수신 가능한 상태 이상의 양호한 상태로 시청자에게 전달되어야 한다. 이를 위해 방송사는 방송 수신 품질을 측정하고 수신이 불량한 지역에 대해서는 송신기 설치, 송신 출력 증강, 중계기 설치 등을 통해 양질의 서비스 제공이 가능한 방송 서비스 영역을 확대한다. 다양한 지상파 방송 매체에서 수신 품질 평가를 위해 가장 많이 측정하는 항목은 전계강도이다. 대부분의 경우 어떤 지역의 전계강도가 해당 매체가 요구하는 기준 레벨 이상이면 해당 지역을 양호 지역으로 평가한다. 본 논문에서는 다양한 지상파 방송 매체에 대한 전계강도를 측정하고 이를 분석할 수 있는 시스템을 제안하고자 한다. 제안 시스템을 이용하면 자동화된 절차에 의해 최단 시간에 다양한 지역에 대한 방송 수신 품질을 측정하고, 그 결과를 분석하여 방송 서비스 영역에 대한 평가를 내릴 수 있으며, 측정결과를 DB로 관리하여 동일 채널에 대한 이전 측정결과와 비교 분석, 다른 채널과 전계강도 비교 분석을 통해 특정 송신기 출력이 감소되거나 특정 안테나 출력에 문제가 발생한 경우에도 이를 쉽게 감지하여 최적의 방송망 구축 및 관리가 가능하다.

• Journal of KIISE
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• v.44 no.5
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• pp.545-552
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• 2017

Because of the explosive growth of mobile devices and development of network technologies, HTTP (Hypertext Transfer Protocol) adaptive streaming has become a new trend in video delivery to provide efficient multimedia streaming services. As interest in personalized broadcasting grows, the study of interactive multimedia has been actively pursued. The interactive multimedia service is a method of playing media according to a scenario selected by the user. Providing the interactive multimedia service with the existing HTTP adaptive streaming causes switching delay and buffer underflow according to the point in time when the user selects the scenario while the client streams the interactive multimedia and therefore decreases the user QoE (Quality of Experience). In this paper, we propose an adaptive streaming scheme for interactive multimedia service in HTTP adaptive streaming to provide seamless playback. We design the architecture and prefetching scheme for interactive multimedia streaming.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.4
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• pp.313-322
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• 2016

This paper presents a method to improve the performance of Scalable Multicast Protocol deployed in wired and wireless network by adding retransmission function on base stations. When using Scalable Multicast Protocol over wireless and wired networks, packet drops on the wireless link produce the initiation of retransmission request packets and the implosion of retransmission packets, which deteriorate the multicast session performance. The efficient reliable multicast mechanism in wireless networks utilizing the retransmission function on the base station is addressed in this paper. We explain the design of a retransmission function which improves the performance of Scalable Multicast Protocol sessions in wireless and wirednetwork. The main idea is to cache Scalable Multicast Protocol packets at the base station and perform local retransmissions across the wireless link. ARENA has been used to simulate and to get performance for reducing signaling overhead and processing delay through the comparison of the proposed function to the Scalable Multicast Protocol.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.934-941
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• 2014

In this paper, we present a low profile 2-layered meander built-in monopole antenna for portable RFID reader using FDTD(Finite Difference Time Domain) method. The input impedance, return loss, and VSWR in the frequency domain are calculated by Fourier transforming the time domain results. The double meander 2-layer structure is used to enhance the impedance matching and increase the antenna gain. The measured bandwidth of the antenna is 0.895 GHz ~ 0.930 GHz for a S11 of less than -10dB. The measured peak gain of proposed low profile RFID built-in antenna is 2.3 dBi. And the proposed built-in antenna for portable RFID reader can offers relatively wide-bandwidth and high-gain characteristics, in respectively. Experimental data for the return loss and the gain of the antenna are also presented, and they are relatively in good agreement with the FDTD results. This antenna can be also applied to mobile communication field, energy fields, RFID, and home-network operations, broadcasting, and other low profile mobile systems.

• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.641-650
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• 2006

There has been a continued increase in the complexity of software equipped with wireless mobile devices, due to the introduction of new device functionality and services via network connection. The increasement expected to be accelerated by convergence of telecommunication and broadcasting, and proliferation of telematics and home networking services using wireless mobile devices. The higher the complexity of mobile device software, the higher the necessity of management for the software. As for the global standard of mobile device management technology, OMA DM has been widely adopted by device manufacture and expected to be accelerated its adoption. In this paper, we present a development result of mobile device software release management system ThinkSync DM SoftMan. The implementation details of ThinkSync DM SoftMan are provided in implementation architecture and its working scenario based on the design of ThinkSync DM SoftMan that is summarized in this paper as our previous work. The conformance and performance test of the system are presented.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.395-402
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• 2016

When the operation of battery is converted at charging and discharging system based on a DC micro grid, the voltage is fluctuated. And excessive voltage fluctuation could cause damage or failure of charging and discharging equipment. Therefore, in this paper, we studied the operating schedule of the charging and discharging system based on the DC micro grid and a design point of the capacitor which was able to reduce the voltage fluctuation. A result of computer simulation showed that when a fluctuation-reducing capacitor which had an initial value of 600V/35mF was applied at the charging and discharging system based on a DC micro grid which was operated with three charging battery sets and five discharging battery sets, voltage fluctuation by charging and discharging operation was reduced by about 63.3%. Furthermore, voltage fluctuation which occurred when initial network voltage was stabilized was reduced by about 73%.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.599-609
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• 2005

There are many test parameters in the DTV measurement, which uses several test measuring instruments and miscellaneous devices. To operate all of those devices and analyse test results is a tedious and time-consuming process with a high error rate committed by inexperienced test crews. In this paper, we propose an integrated DTV measurement and analysis system(IMAS) that remotely controls and manages any instruments with standard network interface. This system can take, organize, store the field data into an integrated database and easily produce systematic output according to user-defined form. It can also measure several types of digital broadcasting signals such as DTV, DMB, DAB with generalized measurement procedures. Proposed measurement system was applied in the DTV field test by KBS and proved that it could enhance the accuracy and efficiency of entire test sequences and also dramatically reduce measurement time compared to conventional measurement systems.

• Archives of design research
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• v.18 no.2 s.60
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• pp.5-14
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• 2005

Graphic Design is being developed as a unique genre and widely applied to movie, TV broadcasting, music video, computer an, web design, animation, and game. Some university added motion graphics in their curriculum recently. However Motion Graphic has not been defined clearly and pedagogy of motion graphics was not studied enough. Motion Graphic is not merely moving picture. Its typical purpose and concept are evolving because of the diversified application. Meta-synthesis between media and hybrid development based on diverse approach and composite presentational methods are also changing Motion Graphic. Various technology such as photograph, analytical engine, hypermedia, multimedia, digital composite picture, network and interface should be studied to understand Motion Graphic. This study reviews the historic background of Motion Graphic mainly related to its advent. A fundamental definition of Motion Graphic including the space and time is suggested and the international trend is introduced. Future Motion Graphic and possible development was also predicted.