• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.22-26
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• 2007

In the fibre to the home (FTTH) era, it is expected that broadband network provisioning will require thousands of optical fibres to be accommodated in a central office for optical access networks. An optical fibre line testing system could be used to reduce maintenance costs and improve service availability depending on the PON's element manager capabilities and the maintenance procedures adopted by the network supplier. When monitoring optical fibres transmitting communication lights, a wavelength of 1625 nm is used for maintenance testing. The splitter installed optical filters allow the communication light to pass but that cut off the test light in the front of optical line terminals (OLTs) and optical network terminals (ONTs). In the economic point of view, We design new planer lightwave circuit splitter embedded filtter and study it optical property.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.2
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• pp.121-128
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• 2010

This paper presents a design of a 100 W high-efficiency power amplifier, whose operational frequency band expands from 30 to 512 MHz, using negative feedback network, push-pull structure, broadband RF choke, and transmission line transformer for balun configuration. The push-pull amplifier has been tuned for higher output power using a shunt capacitor as a matching component at its load especially for high-frequency region. The implemented power amplifier exhibited a very flat power gain of $18.34{\pm}0.9\;dB$ throughout the operating frequency band and very high power-added efficiency(PAE) of greater than 40% at an output power of 100 W. It also showed second- and third-harmonic distortion levels of below -34 dBc and -12 dBc, respectively, through the entire operating frequency band.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.3
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• pp.132-139
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• 2002

The implementation of passive optical network in the access network will result in design of the network that have characteristics of broadband, long distance transmission, transparency. Particularly, optical technologies of WDM and WGR have made a new access network of WDM-PON. This paper proposes the algorithm that determines structural elements of a survivable optical access network, and simulates the cost of various scheme of proposed network architectures. Our results show that multistage star is the most cost effective scheme than the other architectures and show that network architecture designed by proposed algorithm provides survivability with single link and 1st node failure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2011-2018
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• 2009

The international society under the internet technology have been declining boundaries of the global economy. After this step, a social revolution will be happen from the ubiquitous technology which gives objects intelligence to serve people. And then it is expected that every part of a city competitive power is defined by both in quality and in quantity of the ubiquitous information unit in the future. On this score, now each nation is trying to set relative services and broadband networks to lead the ubiquitous industry. Therefore this paper analyzed about the progress and prospect of a local U-city plan in our nation. And than we propose a method of configurating broadband self-communication network on the base of cost and utilization Especially we propose a new city development model which use U-city and self-communication network to improve a city competitive power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1101-1112
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• 2006

With the recent growth in demand for high-data rate multimedia services in the wireless environments, the Mobile Broadband Wireless Access (MBWA) technologies, such as WiBro (Wireless Broadband internet) system, are gradually coming into the spotlight. Unlike the conventional mobile communication networks based on cellular system, the WiBro system basically consists of IP based backbone networks that will be ultimately deployed by Ipv6 (IP version six) based backbone networks according to the All-IP trend for the network evolution. In such wireless mobile environments, it is needed to support the mobility management protocol on network layer as well as physical layer and Medium Access Control (MAC) layer in WiBro system. Accordingly, in this paper, we propose a fast handover scheme for improving the handover performance in IPv6 based WiBro system and show that the proposed scheme achieves loss-free and low handover latency during inter-subnet movement of the mobile stations through the simulation.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.577-585
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• 2010

The Military Tactical Communication technology for effective network-centric warfare is developing. Targeting broadband wireless transmission, core technology for connection, and Transmission technology that secure survivability under High-speed Movement environment. On the one hand, Tactical data communication system that reflects military characteristic is developing on the base of Legacy communication equipment which is used in the field. Because almost every military units in the field have used voice to communicate which lower efficiency of operation, they have made effort to Substitute voice communication which delays military Operation Tempo to digital communication. The Communications environment of troops in Forward edge of battle field area is very poor. Especially in terms of limited frequency allocation and bandwidth. Therefore, improving the efficiency of frequency is essential for Military Tactical Communication. This paper is about The Data Compression Method for increase of Efficiency in Tactical Data Communication over Legacy Radios which are UHF, VHF, HF Radio. I proposed and proved the most efficient Data Compression Method that reflects military characteristic, after analyzing the experimentation, which simulate CAS(Close Air Support mission) data transmission between Pilot and TACP.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.41-51
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• 2017

Recently, Broadband Internet service in the rural area is deployed actively so it will be needed to identify the factors influencing success for continuous spread. In this paper, we explain the users'satisfaction of BcN for rural area and verify success factors such as obstacles the digital divide through the empirical analysis. We select basic variables from Information System (IS) Success Model and add specific variables from former research about overcoming digital divide. The results show that system quality has a significant influence on satisfaction. Use and satisfaction have an impact on eliminating the digital divide in rural area. Based on the findings, academic and practical implications for establishing Broadband Service in rural area are also discussed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.9-14
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• 2016

The Korea Communication Commission(KCC) measures communication qualities of mobile phones' voice calls, mobile internet, and broadband internet to provide quality communication services. It particularly focuses on measuring qualities of mobile internet data that is on the rise in terms of usage. However, existing quality measurement simply measures the speed of mobile communication through data without providing much information to users and does not disclose measured data, making it hard for individuals to objectively determine their communication quality. Thus, to improve such problems, the author suggests a system that measures qualities of mobile communication through Android. The method guarantees user convenience and reliability and improved mobile communication by making it easy for users to select the quantity of data to be used. It also saves the current GPS obtained through GPS module or mobile communication network and transfers measured data to servers so that the data can be processed into new information and be reinterpreted.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.6
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• pp.520-527
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• 2015

The key exchange protocols are very crucial tools to provide the secure communication in the broadband satellite access network. They should be required to satisfy various requirements such as security, key confirmation, and key freshness. In this paper, we present the security functions in ETSI(European Telecommunications Standards Institute), and analyze the specification of the security primitives and the key exchange protocols for the authenticated key agreement between RCST(Return Channel Satellite Terminal) and NCC(Network Control Centre). ETSI key exchange protocols consists of Main Key Exchange, Quick Key Exchange, and Explicit Key Exchange. We analyse the pros and cons of key exchange protocols based on performance analysis and performance evaluation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.7
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• pp.1238-1244
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• 2001

Earlier efforts on optical access concentrated on the design of PONs for the collection and distribution portion of the access network. In these networks the optical hardware in the RN is very simple, but a multiple access protocol is needed for upstream traffic control. On the other hand, the role of communications is already well established in the office environment. With the advent of cheap, affordable broadband communications and the increasing complexity of consumer electronics, it seems natural to extend the network into the home. As the application of Home Area Network is ever increasing, we therefore consider connectivity between access network and home network which generates various traffic to design MAC protocol over residential network. Global-FIFO is quite simple and allows dynamic upstream bandwidth assignment on the basis of a request-and-permit mechanism. It has good bandwidth efficiency and being cell-based, it does not consider the various traffic from home network. In this paper, we design and analyze the new MAC resource assignment algorithm called MQ-FIFO (Multiple Queue-FIFO) that provides good performance under the environment of ATM-PON and Home Network.