• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1998.06a
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• pp.872-875
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• 1998

• Broadcasting and Media Magazine
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• v.12 no.2
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• pp.38-46
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• 2007

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.94-98
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• 2009

A video caption recognition system has been developed for broadcasting sport events such as major league baseball. The purpose of the system is to translate the information expressed in English units such as miles per hour (MPH) to the international system of units (SI) such as km/h. The system detects the ball speed displayed in the video and recognizes the numerals. The ball speed is then converted to km/h and displayed by the following character generator (CG) system. Although neural-network based methods are widely used for character and numeral recognition, we use template matching to avoid the training process required before the broadcasting. With the proposed template matching method, the operator can cope with the situation when the caption’s appearance changed without any notification. Templates are configured by the operator with a captured screenshot of the first pitch with ball speed. Templates are updated with following correct recognition results. The accuracy of the recognition module is over 97%, which is still not enough for live broadcasting. When the recognition confidence is low, the system asks the operator for the correct recognition result. The operator chooses the right one using hot keys.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.55-62
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• 2009

In this paper, we propose a method on the training sequence based on channel estimation issues for relay networks that employ amplify-and-forward(AF) transmission scheme. In $^{[1]}$ and $^{[2]}$, we have to point out that jointly estimating the channel from source to relay and from relay to destination suffers from many drawbacks in fast fading case because the estimation of previous pilots is not suitable for current channel. In this paper, we consider a new joint estimation of overall channel impulse response(CIR) using one OFDM signal without pilots. Using the maximum likelihood(ML) function, we derive a channel estimator by taking the frequency domain of transmitted signal as Gaussian and averaging the ML function over the resulting Gaussian distribution. Simulation results show that our proposed channel estimator performs a fraction of 1dB compared with $^{[1]}$ in high SNR region.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.295-302
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• 2011

In this paper we consider technological requirements to broadcast digital television signals using single frequency networks(SFN) in the Advanced Television Systems Committee(ATSC) transmission systems and propose Interference Cancellation Digital On Channel Regenerative Repeater(IC-DOCR) thar overcomes the limitation of EDOCR(Equalization Digital On Channel Repeater) proposed by ETRI. The proposed IC-DOCR maintains the benefits of EDOCR that have good output signal quality removing multi-path, additive white Gaussian noise(AWGN). In additional, since the Interference Cancellation algorithm using the 8-VSB symbol demodulation of received signal removes the Interference of feedback signal, IC-DOCR improve the weakness of EDOCR that have low isolation between receive and transmit antenna so that can overcome the limitation of output signal power. we did analysis and verification of the proposed system performance using computational simulation.

• Journal of Broadcast Engineering
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• v.13 no.3
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• pp.350-364
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• 2008

Single frequency network (SFN) design based on the Advanced Television Systems Committee (ATSC) specification, a terrestrial digital television (DTV) system, normally causes a interference problem, among signals from multiple transmitters or repeaters. To solve this, the ATSC recommended practice (RP) introduces a transmitter identification (TxID) signal embedded in a signal from each transmitter or repeater. A TxID signal analyzer is then used to detect the TxID signal, and following the analysis results, a SFN design can be adjusted. This paper discusses the generation and usages of Kasami sequence, is used the TxID signal. The configuration of the TxID signal analyzer to efficiently detect TxID signal is proposed and the results of theoretical performance analysis are provided. Moreover, computer simulation and laboratory test results are provided to evaluate the performance of TxID signal analyzer and the theoretical performance analysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.367-370
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• 2017

This paper proposes a method for selecting efficient relay nodes in stochastic DTN model. Delay Tolerant Network (DTN) uses the Carry and Forward method, which creates a bundle layer for efficient communication, selects relay nodes between different networks and heterogeneous networks, and forwards messages. DTN is basically composed of mobile nodes so DTN has no fixed routing route and it has long latency due to intermittent connection. Therefore, the nodes constituting the DTN necessarily have the characteristics to store the messages, and the capacity of the stored messages and nodes affects the performance of the network. Stochastic DTN model proposed a Markov model that changes randomly over time to analyze the performance of DTN. In this paper, we use stochastic message distribution and node contact probabilities using contact time analyzed through message generation and extinction in order to select efficient relay nodes in stochastic DTN model.

• Journal of Broadcast Engineering
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• v.9 no.4 s.25
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• pp.371-383
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• 2004

In this paper we consider technological requirements to broadcast digital television signals using single frequency networks (SFN) in the Advanced Television Systems Committee (ATSC) transmission systems and propose equalization digital on-channel repeater (EDOCR) that overcomes the limitations of conventional digital on-channel repeaters (DOCRs). Since there are no forward error correction (FEC) decoder and encoder, the EDOCR does not have an ambiguity problem. In addition, since an adaptive equalizer in the EDOCR removes multi-path signals, additive white Gaussian noise (A WGN), and feedback signal due to low antenna isolation, the EDOCR may have good output signal quality with high power.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.199-206
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• 1999

본 연구에서는 웹기반의 화물차량위치추적시스템의 개발과 관련된 문제를 다루고 있다. 화물위치추적 시스템이란 이동하는 화물차량으로부터 위치데이터 및 관련 정보를 수신하여 중앙관제센터에서 이 정보를 데이터베이스에 저장하여 두고 화물위치 정보를 지도 위에 표시하는 시스템으로 화주, 운송회사 등 육상물류관련 기관에서 화물위치추적, 공동수배송, 화물차량 통제 등 다양한 목적으로 사용될 수 있다. 화물차량위치추적시스템은 AVLS(Automatic Vehicle Location System)라 불리우면서 산업계에서 활용되고 있으며 위치획득 방법의 종류에 따라 다양한 유형의 AVLS모델이 등장하고 있다. 예를 들면 전통적인 GPS(Global Positioning System) 위성 수신, DGPS(Differential GPS) 기지국, PCS(Personal Communication System) Cell, 도로기반 시설에 포함되는 비콘 등의 방법에 의해 AVLS는 구현되고 있다. AVLS는 정보통신 요소 기술과 정보통신 기반 시설로 구성되는데, 정보통신 요소기술로는 위치획측의 매개체인 AVL단말기와 관제시스템 S/W. 그리고 GIS(Geographic Information System)가 있고, 정보통신 기반 시설로는 차량의 단말기와 관제시스템 사이의 데이터 중계를 담당하는 네트워크가 있다. 화물차량위치추적시스템을 구성하기 위한 구비요건으로 중계망의 안정성과 신뢰성, 획득한 위치데이터의 정확성, 관제시스템의 완성도와 AVL단말기의 사용자 인터페이스, GIS S/W개발을 위한 Map API(Application Program Interface)등을 들 수 있다. 본 연구에서는 PCS Cell 방식에 의한 위치결정방식을 채택하였는데, 이것은 PCS망을 기반으로 데이터를 주고받이며 인터넷 단말기로 확장 가능한 PCS 단말기를 사용해서 위치추적을 하는 시스템이다. 이러한 시스템을 선정하게된 배경은 단말기아 망 이용료의 가격이 저렴하여 현실적으로 트럭이 쉽게 부착할 수 있다는 장점이 있으며 나아가 인터넷 단말기를 활용하여 차량과 관제센터사이에 메시지 전송 등 부가적인 서비스가 가능하기 때문이다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.418-420
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• 2002

휴대용 컴퓨팅이 발전해 나가면서 무선 네트워킹이 등장하게 되었다. 유선 네트워크의 케이블로부터 자유로워지면서 사용자들은 장소의 제약을 덜 받으며 네트워크와 인터넷의 다양한 서비스를 받는 것이 가능해졌다. 무선 네트웍킹 환경이 나날이 발전함에 따라 무선 네트워킹에 관련된 여러 가지 기술이 발표되어왔다. 이들 중 가장 대표적인 것이 바로 무선 랜과 Bluetooth이다. 본 논문에서는 Bluetooth륵 이용한 무선망에 있는 PC와 유선망에 위치한 PC와의 통신을 가능케 하는 어플리케이션의 구현을 통하여 무선망과 유선망간의 데이터 교환 방법을 보였다. 구현된 프로그램은 총 3개로 구성되어 있다. 유선망에 연결되어있지 않은 PC에는 Bluetooth module이 부착되어있고, Bluetooth gateway는 유선망에 연결되어 있으며 Bluetooth module이 부착되어있다. Bluetooth gateway와 유선망의 PC와는 ethernet을 통하여 데이터를 주고받도록 구현하였다. 본 연구에서는 유선망과 무선망을 중계할 게이트웨이를 애플리케이션 레벨에서 분리(split) 방식을 이용하여 구현하였다.