• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.448-450
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• 2001

위성 인터넷 서비스 제공을 위한 시스템 구조는 위성망과 지상망을 함께 이용한 하이브리드형 시스템과 양방향에서 위성링크만을 사용한 양방향 위성 인터넷 시스템이 있다. 본 논문에서는 위성링크를 통하여 정보가 직접 송수신되는 양방향 위성 인터넷 시스템에서 종단간 인터넷 서비스를 제공하기 위한 시스템을 설계하였다. 세부적으로, 시스템 보안, 사용자 인증을 포함한 효과적인 시스템 관리를 위해 IPSec 및 RADIUS시스템의 도입하여 안전하고 안정적인 양방향 위성 인터넷 시스템을 설계하였다. 또한, 패킷 전송시 인증 및 대역폭 할당을 위한 동작 절차를 설계하였다.

• Journal of Advanced Navigation Technology
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• v.20 no.6
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• pp.503-510
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• 2016

In recent years, owing to the growing user demand for the two-way internet service based on the move global broadband communications, a new type of satellite terminal has developed, known as earth station in motion (ESIM). This service was required by Resolution 158 (WRC-15) to study on the coexistence with the co-primary fixed service (FS) in 27.5-29.5 GHz as a FSS uplink. In this paper, four scenarios was introduced to account for the antenna pointing error and the azimuth for an analysis on the sharing between ESIM and FS. From analysis results, the required separation distance between two systems should be about 32~52 km according to the elevation angles of $20^{\circ}{\sim}40^{\circ}$ using thresholds of 5% and 10% outage probability. Therefore, it is necessary to control the azimuth angle due to a moving terminal as well as the pointing error of ESIM to minimize the required separation distance and to protect the co-primary FS.

• Journal of Satellite, Information and Communications
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• v.10 no.4
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• pp.23-27
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• 2015

This paper, discusses about the implementation of the remote control LED Lights in elevator facility Since 1990, the elevator dissemination has greatly increasing. Currently in the elevator most of people they can use smart devices anytime or anywhere to view and retrieve the information by using internet. Therefore, in this paper, efficient management of power LED and LED remote control LED lighting fluid, in order to control features and smart devices can be applied to Web services platform and OS-specific proposals. Additionally based on the configured UI technology and programs offered by the present, and the LED lights are offered through the simulation to efficiently manage technology to demonstrate the usefulness.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.47-54
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• 1997

Today's communication needs the super high-speed data transmission system to send many data rapidly, correctly, and simultaneously because of the increase of internet use, the demand of multimedia service and so on. Before long, the super high data service will be offered us by a satellite called platform which will be located at stratosphere of 20[km]over earth. It is possible to build the optical wireless communication networks which have the high data-tarrying capacity because this system use a laser. But, there are many problems to overcome because it make use of the atmospheric space as transmission channel. In this paper, therefore, we study up on the relations of data rates, bit error rates, and turbulent effects of atmosphere to present the effects of atmosphere to present the effects of atmospheric turbulence on the optical satcom link.

• Korean journal of communication and information
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• v.46
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• pp.9-36
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• 2009

In a competitive media environment, Internet Protocol television (IPTV) has gained appeal because of its essential characteristics, 'Internet and Interactivity'. Our study aims to explore predictors that affect IPTV-VOD adoption within the context of competing media (i.e., existing multi-channel video programming services, such as cable television and digital broadcasting satellite services). In addition, this study examines if IPTV-VOD functions as a substitute for existing multi-channel services, such as cable television and direct broadcasting satellite services. A self-report survey through face-to-face interviews was conducted in Seoul metropolitan area and other six big cities. Our findings showed that primary factors for adopting an IPTV-VOD are: age of user, subjective importance of terrestial broadcasting services, real-time terrestrial broadcasting services, and other interactive service characteristics, such as time-shifting. Also, IPTV-VOD services were found to be a substitute for existing multi-channel video programming services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1285-1294
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• 1999

In this paper we consider the performance of TCP video traffic over ABR with Long-Range Dependent VBR traffic. As compressed coded video traffics are increasing rapidly over Internet, lots of studies are being done for transmitting those traffics efficiently using limited network resources. We consider here the transmitting video service over ABR service in ATM networks, especially satellite networks. CBR or VBR services are suggested in transmitting the video traffic in ATM Forum TM 4.0. But ABR service connection, which is considered as appropriate service for data traffic, can be established with a small amount of bandwidth, MCR (Minimum cell rate). Furthermore ABR service can control the source's transmitting rate using feedback mechanism. Using this feature ABR service can be used in some applications which can control their quality of services corresponding to network loads. Compressed video sources with MPEG-2 are used for Long-Range Dependent VBR traffic here. We model the compressed video source to resemble the MPEG-2 transport streams. These compressed video traffic streams are consisted of three different frames, I-frame, P-frame, and B-frame. So when a network are overloaded, we can control the quality of service using this traffic features. TCP Traffics over ABR need large buffers in ATM switch to satisfy their QoS with background VBR traffics, which have high deviations in bandwidth. Furthermore satellite ATM networks with large feedback delay need large buffers corresponding RTT delay. The performance comparisons among EFCI and ER switch (ERICA+) switches in the network circumstances described above were shown in this paper. We also considered the case with ON-OFF VBR traffics.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.494-497
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• 2008

DIMPEC, Direct Interactive Motion Picture Electronic Commerce technique is not only that gain additional detail information on the entry properties and actor custom by seeing and hearing VOD and TV drama with internet but also source technology which can buy product using electronic commerce. Also, this is enable to construct in variety platform environment like internet, PDA, MOBILE, Settop box, and this is a technology where competition is very high due to application is possible to satellite DMB, and DMB for ground which is high technology IT. DIMPEC is expected that next generation business model will be formed by combining to user participation, consumption magnification of mobile contents, advancement and intelligence of internet service which is next generation internet business model which combines this technique.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.853-871
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• 2012

The location based service is divided into GPS that uses the artificial satellite or base transceiver station in order to cover the wide area and RTLS(Real Time Location System) using the Zigbee, RFID, CSS(Chirp Spread Spectrum), UWB, Bluetooth and Wi-Fi equipment in the space(close range) limited like the building inside or park. Moreover it also repeats the technical development upon through the acceleration of the development of the wire and wireless infrastructure and determination technology, the development of the Internet, diversification of the contents, and etc. As a result, it is expected to develop around the determination technology, witch is common core technology element, contents technology, Internet and mobile communication technology, and etc. afterward. In this research, the direction we investigate was to find and analyze new technology and standardization trend of LBS in order to contribute to the related industry.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2B
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• pp.59-68
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• 2008

In order to activate the digital broadcasting in Korea, the analog broadcasting will have been closed down until 2012. Recently IPTV(Internet Protocol TV) thorough internet has been regarded as the fourth media following the terrestrial, satellite, and cable for the digital broad casting. And it has been the important medium for the communication and broadcasting system. However IP is not easy to replace the entire broadcasting system with the digital - type broadcasting system. For the digital broadcasting, we should replace all TV sets, install the settop-boxes to receive the various IP media, solve problems about time delaying when changing channels, and support communication and broadcasting consolidation service for such as PVR and Network CCTV. IPMG is the digital converter that is able to solve these problems. In this paper, I'll develop and analyze IPMG converter's performance which sends and receives both the analogue and digital broadcasting signals through various media gives the Network PVR service.

• Journal of Advanced Navigation Technology
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• v.26 no.2
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• pp.119-124
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• 2022

The international gnss service (IGS) provides real-time service (RTS) orbit and clock correction applicable to the broadcast ephemeris of GNSS satellites. However, since the RTS correction cannot be received if the Internet connection is lost, the RTS correction should be predicted and used when a signal interruption occurs in order to perform stable precise point positioning (PPP). In this paper, PPP was performed by predicting orbit and clock correction using a long short-term memory (LSTM) algorithm in real-time during the signal loss. The prediction performance was analyzed by implementing the LSTM algorithm in RPI (raspberry pi), the processing speed of which is not high. Compared to the polynomial prediction model, LSTM showed excellent performance in long-term prediction.