• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2004.11a
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• pp.17-20
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• 2004

가정 내에 방송과 총신을 통합하여 제공하기 위한 방법으로서 수동광가입자망(Passive Optical Network)이 제안되고 있다 이를 구현하기 위해 여러 방식들이 연구되고 있는데 크게는 방송과 통신에 각기 다른 파장을 이용하는 방식과, 이들을 시간 다중화 하여 한 개의 과장으로 송신하는 방식으로 나눌 수 있다. 또한 동신에 이용하는 과장의 경우 각 가입자에게 다른 파장을 적용하는 WPON 방식과 모든 가입자에게 한 개의 파장만을 이용하되 시간영역에서 다중화하고 이터넷 프로토콜을 적용하는 EPON 방식으로 구분할 수 있다. WPON의 경우 EPON에 비해 수월하게 광대역 서비스를 할 수 있는 장점이 있으나, 각 가입자 과장의 제어 및 관리가 복잡하며, 고비용을 요구한다. 반면 EPON의 경우 채널의 효율성은 극대화할 수 있으나, 동시 이용자가 많을 경우 전송 속도가 하락한다. 한편, 방송과 통신을 통합한 채널의 특성을 살펴보면 가입자 방향으로의 하향 신호의 양이 중양국 방향으로의 상향 신호의 양에 비해 훨씬 많은 비대칭 구조이다. 따라서 본 연구에서는 이러한 채널 특성에 맞도록 하향 전송에는 WPON의 구조를 이용하고, 상향 전송에는 EPON의 구조를 적용하는 새로운 구조의 광가입자망을 제안하였다. 제안된 구조에 적합한 MPCP (Multi-Point Control Protocol) 프로토콜을 제시하고, 가입자 장치의 여러 종속 신호를 다중화하고 전송할 수 있는 ONU (Optical Network Unit)의 구조를 제안하였다. 또한 이러한 구조를 갖는 W-EPON 테스트베드를 구현하고 전송 시험을 통해 제시된 구조의 적합성을 측정한 결과를 보인다.4 Textual format) 파일을 생성한다. 또한, 콘텐츠 전송 및 저장의 효율성을 위해 이진 포멧인 IPMP화된 MP4 파일을 생성할 수 있다.으로써, 에러 이미지가 가지고 있는 엔트로피에 좀 근접하게 코딩을 할 수 있게 되었다. 이 방법은 실제로 Arithmetic Coder를 이용하는 다른 압축 방법에 그리고 적용할 수 있다. 실험 결과 압축효율은 JPEG-LS보다 약 $5\%$의 압축 성능 개선이 있었으며, CALIC과는 대등한 압축률을 보이며, 부호화/복호화 속도는 CALIC보다 우수한 것으로 나타났다.우 $23.87\%$($18.00\~30.91\%$), 갑폭 $23.99\%$($17.82\~30.48\%$), 체중 $91.51\%$($58.86\~129.14\%$)이였으며 성장율은 사육 온도구간별 차는 없었다.20 km 까지의 지점들(지점 2에서 지점 6)에서 매우 높은 값을 보이며 이는 조석작용으로 해수와 담수가 강제혼합되면서 표층퇴적물이 재부유하기 때문이라고 판단된다. 영양염류는 월별로 다소의 차이는 있으나, 대체적으로 지점 1과 2에서 가장 낮고, 상류로 갈수록 점차 증가하며 지점 7 상류역이 하류역에 비해 높은 농도이다. 월별로는 7월에 규산염, 용존무기태질소 및 암모니아의 농도가 가장 높은 반면에 용존산소포화도는 가장 낮다. 그러나 지점 14 상류역에서는 5월에 측정한 용존무기태질소, 암모니아, 인산염 및 COD 값이 7월보다 다소 높거나 비슷하다. 한편 영양염류와 COD값은 대체적으로 8월에 가장 낮으나

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.153-158
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• 2016

Broadcasting in multi-hop wireless sensor networks is a basic operation that supports many applications such as route search, setting up addresses and sending messages from the sink to sensor nodes. The broadcasting using flooding causes problems that can be mentioned as a broadcasting storm such as redundancy, contention and collision. A variety of broadcasting schemes using wireless sensor networks have been proposed to achieve superior performance rather than simple flooding scheme. Broadcasting algorithms in wireless sensor networks can be classified into six subcategories: flooding scheme, probabilistic scheme, counter-based scheme, distance-based scheme, location-based schemes, and neighbor knowledge-based scheme. This study analyzes a simple flooding scheme, probabilistic scheme, counter-based scheme, distance-based scheme, and neighbor knowledge-based scheme, and compares the performance and efficiency of each scheme through network simulation.

• Journal of Information Technology Applications and Management
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• v.22 no.2
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• pp.43-70
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• 2015

Concerns have been growing about whether domestic internet protocol television (IPTV) can establish a solid foothold in the pay TV market, largely because of the lack of IPTV-only content and service differentiation. It has been difficult for IPTV providers to attract valuable PPs (program providers) to strengthen their positions, and IPTV providers have invested much money into procuring content. To survive this difficult situation, IPTV providers need to reappraise their profit sharing methods and content distribution structure to facilitate the expansion of their subscriber base. This can be done by attracting valuable PPs to IPTV providers and securing extra revenue by distributing more content for their PP partners. The IPTV industry has a different structure and value chain from the digital cable industry. Moreover, profit sharing schemes among participants in the IPTV industry are complicated. Thus it is essential to analyze the criteria for profit sharing, the selection of attributes in profit sharing, and their cause-effect relationship in developing fair pricing for broadcast content in the IPTV industry. This study introduces the attributes that need to be considered for the pricing of content and profit sharing among IPTV providers and PPs. In addition, this study uses system dynamics to analyze the relationship among those attributes along with additional associated factors for the pricing of content.

• International journal of advanced smart convergence
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• v.5 no.3
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• pp.61-65
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• 2016

In the TV broadcasting, movie production and business the transportation of video between creators (programmers, studios) and distributors (broadcast and cable networks, cable and satellites companies) is still a mix of File Transfer Protocol (FTP), physical delivery, and expensive multicast satellite. Cloud-based file sync-and-share providers like Dropbox and box are playing an increasing role, but the industry's unique demands for speed and multicasting have fueled the growth of IP Video transport. This paper gives a solid grasp of the major elements of IP video technology, including content preparation, system architecture alternatives and network performance management.

• Journal of the Korea Society for Simulation
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• v.12 no.4
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• pp.73-81
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• 2003

An Ad Hoc network is a dynamic multi-hop wireless network that is established by a group of mobile hosts on a shared wireless channel by virtue of their proximity to each other. Since wireless transmissions are locally broadcast in the region of the transmitting host, hosts that are in close proximity can hear each other and are said to be neighbors. The transitive closure of the neighborhood of all the hosts in the set of mobile hosts under consideration forms an Ad Hoc network. Thus, each host is potentially a router and it is possible to dynamically establish routes by chaining together a sequence of neighboring hosts from a source to a destination in the Ad Hoc network. In a network, various real-time services require the network to guarantee the Quality of Services provided to the receiver. End-to-end QoS can be provided most efficiently when each layer of the protocol stack translates the requirements of the application into layer classified requirements and satisfies them. In this study, a mechanism to guarantee the QoS in Ad Hoc networks with buffer nodes is proposed. They effectively prevent traffic congestion and yield better transmission rate. In this way QoS is enhanced.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1555-1558
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• 2002

현재 여러 기관에서 사용하고 있는 방송 시스템은 스튜디오, 방송 장비의 설치 및 확장에 대한 불편함과 비용의 부담, 거리에 따른 방송품질의 저하 등 많은 문제점을 가지고 있다. 이를 해결하기 위한 대안으로 인터넷을 이용한 방송 시스템이 등장하였다. 이는 별도의 시스템 추가 없이 인터넷이 연결되어 있는 장치를 이용하므로 비용절감과 설치의 간편함, 일정한 방송품질을 제공할 수 있다. 그러나 현재 소개되어 있는 인터넷을 이용한 방송 시스템들은 독자적 합의에 의한 호 설정으로서, 시스템 확장과 선택에 대하여 매우 낮은 퍼포먼스를 제공한다. 이를 해결하기 위해 차세대 네트워크 서비스로 각광받고 있는 SIP(Session Initiation protocol)을 이용하여 방송 시스템을 설계 및 구현 하였다.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.45-46
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• 2007

In order to go digital broadcasting in Korea, it is conducted various policies in the country which be expanded network, be increased digital broadcasting hours. And broadcasting stations in the country close down analog broadcasting until 2012. Moreover IPTV is a method of delivering broadcast television and on-demand, rich media content that uses an IP(Internet protocol network) as the medium. And an IP is regarded as a very favorable approach for the future "Medium for Digital TV". However It is not easy to replace the entire digital infrastructure. And there are some problems in the digital infrastructure for Digital TV(i.e. channel zapping delay). Moreover user require service. IPMG is to solve these problems. IPMG is digital converter that allows receive and transmit signal by using many kinds of medium for Digital TV. Moreover IPMG provides users a Network PVR service. In this paper we developing, manufacturing IPMG and analyze its performance.

• Journal of Communications and Networks
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• v.11 no.3
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• pp.248-260
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• 2009

To connect a mobile ad hoc network (MANET) with an IP network and to carryout communication, ad hoc network node needs to be configured with unique IP adress. Dynamic host configuration protocol (DHCP) server autoconfigure nodes in wired networks. However, this cannot be applied to ad hoc network without introducing some changes in auto configuration mechanism, due to intrinsic properties (i.e., multi-hop, dynamic, and distributed nature) of the network. In this paper, we propose a scalable autoconfiguration scheme for MANETs with hierarchical topology consisting of leader and member nodes, by considering the global Internet connectivity with minimum overhead. In our proposed scheme, a joining node selects one of the pre-configured nodes for its duplicate address detection (DAD) operation. We reduce overhead and make our scheme scalable by eliminating the broadcast of DAD messages in the network. We also propose the group leader election algorithm, which takes into account the resources, density, and position information of a node to select a new leader. Our simulation results show that our proposed scheme is effective to reduce the overhead and is scalable. Also, it is shown that the proposed scheme provides an efficient method to heal the network after partitioning and merging by enhancing the role of bordering nodes in the group.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.384-387
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• 2003

In this paper, we have designed the integrated wire and wireless P2P framework using mobile agents to share efficiently resources as media file. Most of the P2P applications are used on the wire network. We propose the integrated wire and wireless P2P framework. Proposed P2P platform is based on JXTA of Sun Microsystems. But JXTA is pure peer-to-peer network model, so it sends message other peers as broadcast style to request resources. In this way, there are some problems as massage overload, bandwidth loss, etc. In order to solve this problem, we propose a hybrid peer-to-peer network model using mobile agent. Proposed scheme also solve existing hybrid pEp model's flaws which have the delay and low rate due to concentrated server. In proposed scheme, mobile agents that have autonomy and mobility are used to search the location of resources. Besides, mobile agents could solve the loss problem of the search result. To improve P2P QoS(Quality of Service), we could monitor peer's state information using PIP(Peer Information Protocol) of JXTA.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.9
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• pp.433-444
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• 2005

In video-on-demand(VOD) systems, a broadcast-based scheduling mechanism is known to be a very efficient technique for disseminating popular videos to very large client populations. The main motivations of broadcasting scheduling mechanisms are that they scale up extremely well and they have very modest bandwidth requirements. This paper proposes a new dynamic broadcasting scheduling mechanism, named FDBS (fast dynamic broadcasting scheme), and proves its correctness. This paper also evaluates the performance of FDBS on the basis of a simulation approach. The simulation results indicate that FDBS shows a superior performance over UD, CBHD, and NPB in terms of the average response time with very reasonable bandwidth requirements.