• Journal of Environmental Science International
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• v.21 no.2
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• pp.241-251
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• 2012

The emissions of several air pollutants ($NO_x$, CO, VOCs, etc.) for the replacement of all diesel buses by Compressed Natural Gas (CNG) buses were estimated in the Busan Metropolitan Area (BMA). These emissions were calculated from emission factors considering the different driving speeds with bus routes, distance traveled, and deterioration factors. For the purpose of this study, three categories of fuel type were selected: (1) the combination of diesel (65%) and CNG buses (35%) (DSL+CNG case), (2) all diesel buses (DSL case), and (3) all CNG buses (CNG case). The emissions of $NO_x$ and CO in the CNG case were estimated to be significant decreases (by about 50% and 98%, respectively) relative to the DSL case. Conversely, the emission of VOCs (980.7 ton/year) in the CNG case were a factor of 3.3 higher than that (299.8 ton/year) in the DSL case. In addition, the diurnal variations of emissions between two city buses (e.g. diesel and CNG) and all other vehicles were distinctly different because the two city buses operate at a regular time interval. Our overall results suggest the possibility that the pollutant emissions from the CNG buses can exert less influence on air quality in the target area than those from the diesel buses.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.06a
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• pp.107-113
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• 2002

We have developed the MIBs for Access Gateway which is for diverse subscribers to access the core network at the NGN. We organized the subscriber and network interface Information such as xDSL, ATN, PSTN, MIBs, and so on. The MIBs are managed by EMS.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.53-55
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• 2005

일반주택지역을 위한 초고속인터넷 제공방안은 xDSL과 HFC 기술방식이 적용되어 왔다. HFC는 전송속도의 기술적 한계를 가지며, xDSL은 기존 동선을 활용하는 솔루션으로 경제적인 장점을 가지지만 동선 선로품질에 따라 품질저하가 발생한다. 이에 UTP케이블이 기포설된 1등급 아파트에만 공급 가능하였던 100Mbit/s 패스트이더넷을 일반주택지역에 공급하기 위한 유사FTTH 시스템이 개발되어 현장에 운용 중이다. 광코어 절감 및 운용유지 측면을 고려하여 WDM-PON (Wavelength Division Multiplexing-Passive Optical Network, 파장분기 수동형광가입자망) 방식을 채택하였으며, 가입자 인근 전주까지 광케이블이 포설되어 ONU(Optical Network Unit)가 설치되며, ONU로부터 가입자 댁내 단말까지 가공형 UTP케이블을 통해 패스트이더넷을 공급하는 방식이다.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.1 s.61
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• pp.65-75
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• 2007

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3B
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• pp.314-324
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• 2004

Recently, high-speed internet subscribers have grown continuously, and reached up to 10 millions. But existing network management that is responsible only for user access is confronted with many difficulties, since user access network(xDSL, Cable, B-WILL, and so on) has diversified and value added wired/wireless contents service has developed. In this paper propose the Agent based Inter Networking platform as object-oriented hierarchical system that can provide various service such as access QoS(Quality of Service), customized application service and security service according to user on demand. This system has divided into two parts(user agent and agent management system ＆ local and central management systems). Management system periodically receive status information such as bandwidth, download speed, delay, current service, and so on, and process them, then build a policy based on processed information. According to personal user profile that is generated by this policy, the customized service can be provided for users. And This system adopt the object-oriented modeling in case that system migration and integration, and implement a system that is robust and stable for security through hierarchical server system.

• Proceedings of the CALSEC Conference
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• 2003.09a
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• pp.8-14
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• 2003

디지털콘텐츠 세상 디지털콘텐츠에 대한 기대 ㆍ멀티미디어 압축 기술 동의 발전 ㆍ인터넷을 통한 멀티미디어 전송 기술 발달 ㆍ광대역 네트워크 및 xDSL, Cable modem과 같은 네트워크 기술 발달 ㆍ이용자의 멀티미디어 기대치 증가 ㆍ디지털 정보의 장점(무한사용, 가공재생, 저장, 비손실성, 접근용이성,...)(중략)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.472-475
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• 2001

본 논문은 경제적, 기술적 문제로 도외시되었던 메트로 이더넷의 새로운 등장 배경 및 기술동향과 향후 전망에 대해 기술하고 있다. 메트로 이더넷은 기존의 LAN, WAN 장비시장을 대체하는 기술인 동시에 xDSL기술의 대안으로도 사용될수 있으며, 요즘 이슈가 되고 있는 사이버 아파트 랜솔루션등으로 가능성을 지니고 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5A
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• pp.545-553
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• 2004

Expansion of network environment and multimedia demand universality of application service as HDTV, etc. During these processes, it is essential to process multimedia in real time in the wireless communication system based on mobile phone network and in the wire communication system due to fiber cable and xDSL. So, in this Paper the optimal memory allocation algorithm combines the merit of huffman encoding which is superior in simultaneous decoding ability and lempel-ziv that is distinguished in execution of compress is proposed to improve the channel transmission rate and processing speed in the compressing procedure and is verified in the entropy encoder of HDTV. Because the entropy encoder system using proposed optimal memory allocation algorithm has memory saturation prevention we confirms that the compressing ratio for moving pictures is superior than Huffman encoding and LZW.

• The KIPS Transactions:PartA
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• v.11A no.6
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• pp.433-438
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• 2004

In this paper, we describes the development of Bluetooth network Access Point(AP) for the access network connection of Bluetooth devices at home. Unlike headset, mouse, and keyboard, the AP should have capability to support multiple connection and stabilized network throughput. Our AP allows various kinds of Bluetooth terminals to access the access network like xDSL and PSTN(Public Swithced Telephone Network) stably. Especially, users can access the PSTN at home instead of expensive CDMA network through the AP by using the one-phone which is the cellular phone with the Bluetooth module.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.2
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• pp.102-106
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• 2011

The transfer capability of HFC (Hybrid Fiber Coax) network is superior to xDSL. HFC network, however, is not suitable for transferring high quality video due to cable model interfaces. For the services of high quality IPIV or VOD, the extra exclusive downstream transfer system is required without upgrading pre-equipped cable modem and service capability. This paper is aimed to develop the extra exclusive downstream transfer system not changing existing cable modem system but providing same quality of services. This system is composed of the extra exclusive downstream IP-cable sender and modem. This sender and modem have 30 Mbps transfer capability and HDTV stream can be served in the Cable TV network using 21 Mbps HDTV transport stream.