• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.254-255
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• 2013

최근 다양한 종류의 재난 발생이 증가와 그 피해로 인해 재난에 대한 관심이 높아지고 있다. 특히 재난이 발생 징후가 포착되었을 때나 재난이 발생하였을 때 그 정보를 신속하고 정확하게 전달하고자 국내에서는 각 재난의 특성에 맞는 다양한 종류의 경보시스템을 개발하여 운영하고 있다. 하지만 다양한 경보시스템들은 그 관리책임기관이 다르기 때문에 개별적으로 등장하였다. 그래서 하나의 경보를 전달하기 위해 여러 시스템을 각각 동작시켜야 하는 등의 비효율성의 문제가 발생하였다. 이와 같은 문제를 해결하기 위해 미국, 유럽등지에서는 재난관리 시스템을 통합하려는 연구를 진행하고 있으며, 국내에서도 통합경보시스템을 위한 연구가 진행되어 이 연구 결과로 "이기종 경보 시스템 서버와 통합 재난 경보 게이트웨이 연계 프로토콜" 표준이 제정되었다. 이에 본 논문은 통합재난경보네트워크(IDAN: Integrated Disater Alert Network)를 계층적으로 분석하고, 경보전달을 위한 국제 표준인 CAP(Common Alerting Protocol)과 비교 연구하여 IDAN의 문제점을 제시하고 이를 해결하기 위한 방법을 제안한다.

• Journal of information and communication convergence engineering
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• v.9 no.2
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• pp.244-250
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• 2011

Gossip is a well-known protocol which was proposed to implement broadcast service with a high reliability in an arbitrarily connected network of sensor nodes. The probabilistic techniques employed in gossip have been used to address many challenges which are caused by flooding in wireless sensor networks (WSNs). However, very little work has yet been done on real-time wireless sensor networks which require not only highly reliable packets reception but also strict time constraint of each packet. Moreover, the unique energy constraining feature of sensor makes existing solutions unsuitable. Combined with unreliable links, redundant messages overhead in real-time wireless sensor networks is a new challenging issue. In this paper, we introduce a Reliable Gossip Zone, a novel fine-tailored mechanism for real-time wireless sensor networks with unreliable wireless links and low packet redundancy. The key idea is the proposed forwarding probability algorithm, which makes forwarding decisions after the realtime flooding zone is set. Evaluation shows that as an oracle broadcast service design, our mechanism achieves significantly less message overhead than traditional flooding and gossip protocols.

• Journal of Broadcast Engineering
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• v.8 no.4
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• pp.427-436
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• 2003

Many applications that are transport multimedia data through the networks should put existing network structure to practical use. Because the existing network structure and protocols are designed for static data transmission, multimedia applications with timing concept have limitations for using existence. In this paper, we present limitations of existing network structure for multimedia delivery, survey network element's characteristics in side view of multimedia application, present the streaming protocol for realtime multimedia traffic. Lastly, we consider a protocol stack for MPEG-21 Digital Item transmission using these existing protocols.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.11-14
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• 2008

본 논문에서는 ATSC 기반 국내 지상파 DTV 방송신호를 대상으로 ATSC A/65c(Program and System Information Protocol; PSIP) 및 A/57b(Content Identification and Labeling for ATSC Transport) 표준규격 기반의 방송프로그램ID 규격을 제안한다. 특히, 현재 방송사 내부적으로 운영되고 있는 콘텐츠 식별관리 방식의 독자성을 유지하고, 지상파방송 서비스 환경의 특수성을 반영한 지상파 방송프로그램 식별정보인 방송프로그램ID 구조를 제시한다. 또한 방송프로그램ID 삽입/추출기의 구현 및 실험과정을 통하여, 국내 지상파 DTV 방송 송수신규격과의 정합 및 방송프로그램ID의 기능 검증을 수행한다.

• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.596-610
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• 2012

This paper proposes a method to provide the high quality 3D broadcasting service in a mobile broadcasting system. In this method, audio and video data are delivered through a heterogeneous network, consisting of a mobile network as well as a broadcasting network, due to the limited bandwidth of the broadcasting system. However, it is more difficult to synchronize the left and right video frames of a 3D stereoscopic service, which come through different types of networks. The proposed method suggests the use of the offset from the initial timestamp of RTP (Real Time Protocol) to determine the order of frames and to find the pair of a left and a right frame that must be played at the same time. Additionally, a new signaling method is introduced for a mobile device to request a 3D service and to get the initial RTP timestamp.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.847-853
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• 2014

When a disaster occurs, effective alerts will reduce human life and property loss. The Integrated Emergency Alert System is a national disaster management system which integrates existing alert systems to deliver effective disaster alerts. Alert message exchange protocol is the essential technology for the System. In Korea, the first specification for "Common Alerting Protocol Profile for Integrated Emergency Alert System" was established in 2014. In this paper, we derive two additional requirements for more enhanced alert service and propose revision of the specification: multilingual alert service for foreigners and more flexible representation of target area. We review the associated foreign profile specifications as well as the domestic specifications to analyze these requirements. Finally, we propose the most efficient way to deliver multilingual alert message and to represent target area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1306-1312
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• 2017

The route request (RREQ) packet is selectively re-broadcasted in the routing protocols that improve the broadcast storm problem of the ad-hoc on-demand routing protocol (AODV). However, in a low node density scenario, the connectivity of these selective rebroadcast schemes becomes less than that of the AODV. In order to clarify the requirements of these selective re-broadcast routing protocols, it is necessary to investigate the relationship between the node density and the connectivity. In this paper, we drive a probability to preserve the connectivity of the GAODV at an intermediate rebroadcast node. In addition, we present an intuitive method to approximate the end-to-end connectivity of the GAODV. We draw the required node density to guarantee the connectivity of 0.9 and 0.99 through computer simulations, and verify the validity of the derived theoritical connectivity by comparing with the simulation results.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.738-749
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• 2011

In this paper, we study QoS(Quality of Service) control protocols and the effect using MAC/PHY parameters of client device in mobile network. We proposes the way of controling the bit-rate by estimating the channel condition of the client with measured MAC/PHY parameters which is sent from the client. With the proposed method, more accurate available bit-rate can be estimated compared to conventional protocol, RTCP(Real-time Transport Control Protocol). The accurate bit-rate estimation can decrease wasted bit-rate and transport delay. In the result of the advantages, the transported video quality can be enhanced. In this paper, we show the effects of enhancement using client's the field data measured in WiMAX.

• Journal of Broadcast Engineering
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• v.13 no.1
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• pp.62-68
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• 2008

Remote user authentication scheme is a cryptographic tool which permits a server to identify a remote user. In 2007, Wang et al. pointed out that Ku's remote user authentication scheme is vulnerable to a dictionary attack by obtaining some secret information in a smart card using side channel attacks. They also proposed a remote user authentication scheme which is secure against dictionary attack. In this paper, we analyze the protocol proposed by Wang et al. In the paper, it is claimed that the protocol is secure even though some values, which is stored in a smart card, are revealed to an adversary, However, we show that their protocol is insecure if the values are disclosed to an adversary.

• Journal of Broadcast Engineering
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• v.13 no.2
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• pp.245-250
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• 2008

Efficient service discovery mechanism is a crucial feature for the usability of a wireless ad-hoc network. A wireless ad-hoc network is a temporal network formed by a collection of wireless mobile nodes without the aid of any existing network infrastructure or centralized administration. We propose an efficient service discovery mechanism using non-disjoint multi-path routing protocol for a wireless ad-hoc network. Our scheme has advantages of not only multi-path routing protocol but also cross-layer service discovery. By simulation, we showed that faster route recovery is possible by maintaining multiple routing paths in each node, and the route maintenance overhead can be reduced by limiting the number of multiple routing paths and by maintaining link/node non-disjoint multi-path.