• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1991.10a
• /
• pp.464-464
• /
• 1991

We address the problem of designing a physical CATV network with switched-star topology in which the broadband interactive service is provided. There are two types of decision variables: One is where to place conduit paths, and the other is how many cable units to be installed on each link traversed by an established conduit path. Due to the serious drawback of the conventional approach partitioning the problem into two subproblems, the unified approach handled in one setting is used here to attack the whole problem without dividing into two ones. In this paper, we present a mathematical design model and propose an efficient solution method exploiting the nice structure of it. In addition to this physical design, some results on logical network configuration have also been made. Finally, computaional experiments are conducted to illustrate the efficiency of our design approach.

• Proceedings of the KIEE Conference
• /
• 2002.07d
• /
• pp.2540-2542
• /
• 2002

In recent years, it is a worldwide trend that many power utilities focus their attention to employ up-to-date communication technology to the automation of their power plants and distribution systems. Automation Systems in Korea was installed using twisted pair cable(TPC), power line carrier(PLC), coaxial cable(CA), wireless network(wireless data, TRS and PCS). Among the communication media only Satellite Communication guarantees the reliable communication in case of emergency such as a flood, a heavy snow and an earthquake. It can integrate two-way satellite systems to existent nationwide SCADA controlling points of electric power transmission & distribution system that enables real time remote monitoring and controlling automatically. This paper presents some of design efforts for the satellite communication network as the media of Automation Systems.

• Electronics and Telecommunications Trends
• /
• v.11 no.4 s.42
• /
• pp.63-75
• /
• 1996

본 고에서는 일반 가정 및 소규모 업무용 가입자들에 대한 광대역화의 가장 경제적인 대안으로 관심을 끌고 있는 Hybrid fiber-coax 구조의 CATV 전송망에 대한 표준화 동향에 대해 조사 분석한 내용을 기술한다. HFC 액세스망에 대한 표준화는 IEEE 802.14 그룹, DAVIC, ATM Forum, IETF(Internet Engineering Task Force)와 Cable TV업계 등 여러기구에서 추진하고 있다. 지금까지 물리계층, MAC계층 등에 대한 주요 표준규격에 대해 DAVIC과 IEEE 802.14에서 주도하고 있으나, 앞으로는 데이터 서비스에 상대적 우선 순위를 두고 표준화를 추진하는 IEEE 802.14그룹에서 주도하게 될 것으로 보인다. 또한 인터넷 접속과 고속 데이터 서비스를 위한 인터페이스와 IP 접속 프로토콜에 대한 표준화를 발 빠르게 추진하고 있는 IETF와 MCNS(Multimedia Cable Network System) 등의 역할이 커질 것으로 전망된다.

• Korean Journal of Optics and Photonics
• /
• v.6 no.4
• /
• pp.379-384
• /
• 1995

In order to construct B-ISDN, it is inevitable to introduce optical fiber of low loss and wide bandwidth. Coincidently, high count optical fiber cable is solely important to form optical subscriber network. The best structure of high count optical fiber cable to achieve multi-splicing as well as high density at the same time is the one of taking optical ribbon as a unit of accomodation. However, since optical ribbon has its own width. optical loss due to length difference during the bending of ribbon cable unit occurs in relatively easy way. Therefore, care should be taken during its manufacturing and storage. In t\1::; paper, strain, bending radius and lateral pressure of each fiber in ribbon due to the bending of ribbon cable unit are caculated theoretically. Hence, we have measured optical loss of each fiber as function of unit bending radius, when we bent the ribbon cable unit on the various reel. We found that the result accords well with the theoretical analysis. The result shows the importance to determine proper radius of reel used in ribbon cable manufacturing and storage. orage.

• Structural Engineering and Mechanics
• /
• v.23 no.4
• /
• pp.449-454
• /
• 2006

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39A no.6
• /
• pp.357-364
• /
• 2014

In this paper deals with PON Remote monitoring solution using Reflecting Filter. The current FTTH-PON can not be monitored in real time that Optical cable fault and Quality degradation of Splitter. To solve this problem, Monitoring can make Feeder Network and Splitter that Reflecting filter development using the basic structure of Fiber Bragg grating. Reflecting Filter is Quality Monitoring System shall provide tools for user to view and analyze degradation of cables and splitter in particular predict any gradual component degradation(Optical cable bending, splice, connector, etc) before it becomes service impacting. The Reflecting Filter solution is splitter down and confirm the fault location of optical cable and it will send central control station can be monitored system an alarm to the OLT. In other words, wavelength side branches Mating existing communication affairs (Coupler) using the core of one optical wavelength for live monitoring two wavelengths and sends the subscriber side modem and aggregation switch device remotely using a reflective optical line filter monitoring the study of the system. this study can development of Reflecting filter improve the average processing time of Optical cable fault and efficient Maintenance of the network.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.9A
• /
• pp.1332-1339
• /
• 2000

This paper presents the architecture and design of a high speed asymmetric data transmission baseband MODEM ASIC chip for CATV networks. The implemented MODEM chip supports the physical layer of the DOCSIS(Data Over Cable Service Interface Specification) standard in MCNS(Multimedia Cable Network System) The chip consists of a QPSK/16-QAM transmitter and a 64/256-QAM receiver which contain a symbol timing recovery circuit, a carrier recovery circuit, a blind equalizer using MMA and LMS algorithms. The chip can support data rates of 64Mbps at 256 QAM and 48Mbps at 64-QAM and can provide symbol rates up to 8MBaud. This symbol rate is faster than existing QAM receivers. We have performed logic synthesis using the $0.35\mu\textrm{m}$ standard cell library. The total number of gates is about 290,000 and the implemented chip is being fabricated and will be delivered soon.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2013.11a
• /
• pp.196-199
• /
• 2013

제한수신시스템(Conditional Access System, CAS)은 사용자의 조건에 따라 방송에 대한 접근을 제어하는 시스템으로 유료 방송 시스템에서 인가된 사용자만이 해당 프로그램에 접근할 수 있도록 하는 콘텐츠 보안 기술이다. 최근에는 기존의 하드 웨어 기반 CAS가 가지는 이기종 기기간 호환성과 다른 서비스와의 연동 등의 문제를 해결하고자 CAS 모듈을 소프트웨어로 구현하여 네트워크를 통해 설치하는 교환 가능형 제한수신시스템(eXchangeable CAS, 이하 XCAS) 방식을 도입하여 활발하게 서비스를 제공하고 있다. XCAS는 기존 CableCard방식이 가지는 CAS의 보안성과 분리교환 원칙을 유지하면서도 다양한 단말에 쉽게 설치하여 서비스가 가능하다는 점에서 큰 장점을 가지고 있지만, 방송수신만을 목적으로 하는 DTV(Digtal Television)에 대해 적용하기가 어렵다는 문제점이 존재하였다. 본 논문에서는 케이블방송환경에서 DTV를 통한 유료방송서 비스 제공을 위한 DTV 인증 및 XCAS 서비스에 필요한 SM(Secure Module) 모듈을 다운로드하기 위한 기법을 제안한다.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.1977-1983
• /
• 2009

This paper described partial discharge(PD) patterns depending on types of insulation defects in CNCO-W cable(Concentric Neutral Closs-linked Polyethylene Insulated Polyolefin-Water Proof Sheathed Power Cable). The PD measurement system consists of a coupling network, a detection impedance, and a low noise amplifier. A 16 bit, 250 MS/s data acquisition system was used to analyze PD patterns. To simulate insulation defects in a power cable, a needle with the curvature radius of $10{\mu}m$ was inserted into the insulation part. We measured phase ($\Phi$), magnitude (q), and counts (n) of PD pulse for the defects, and classified PD patterns using the PRPD (phase Resolved Partial Discharge) method. From the analysis of acquired PD signals, we could find that a unique PD pattern is formed according to the types of defect.

• Proceedings of the KSR Conference
• /
• 2003.10c
• /
• pp.653-658
• /
• 2003

This study is represented a method to give connect to optical cable from accident site and reviewed the method to transmission a moving image to control centre by real time, following the study of image transmission method in copper cable section where is a main line of railroad communication. Concept of network is studied to use cable and equipment effectively, and it's also reviewed technology of digital image transmission system and image evaluation methods, in spite of the pixel of camera and monitor resolution determine quality of image when moving image transferring by point to point. In addition, this study is reviewed checks and considerations of image transmission equipment (codec) with various transmission methods in room test, and then examined and analyzed wire/wireless combined transmission methods at wayside.