• Journal of Internet Computing and Services
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• v.8 no.5
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• pp.161-170
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• 2007

The proposed switch which has separated data plane and switching plane can make parallel processing for packet data storing, memory address pointer switching and simultaneously can be capable of switching the variable length for IP packets. The proposed architecture does not require the complicated arbitration algorithms in VOQ, also is designed for QoS of generic output queue switch as well as input queue. At the result of simulations, the proposed architecture has less average packet delay than the one of the memory-sharing based architecture and guarantees keeping a certain average packet delay in increasing switch size.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.769-771
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• 2004

급증하는 무선 인터넷 서비스 요구에 효과적으로 대처하기 위해서는 휴대성과 이동성이 보장되며 저렴한 요금을 지향하는 새로운 형태의 무선데이터 시스템인 초고속 휴대용 인터넷(High-speed Portable Internet: HPi) 시스템이 요구된다. ETRI(Electronics and Telecommunications Research Institute)에서 독자 개발 중인 HPi 시스템은 IEEE 802.16 표준을 기반으로 서비스 분류에 따른 차별적인 서비스를 제공한다. 이동 단말이 서로 다른 셀 영역을 이동할 경우 핸드오버를 수행하고 핸드오버 동안의 패킷 유실 발생을 방지하기 위하여 이전 AP에서 패킷 버퍼링을 해야한다. 따라서 핸드오버 동안에 HPi에서 제공하는 서비스 분류에 따른 차별적인 품질을 보장하기 위하여 서비스 클래스에 따른 차별적인 패킷 버퍼링 메커니즘이 필요하다. 본 논문에서는 HPi에서의 핸드오버 시 차별적인 서비스 품질 보장을 위한 패킷 버퍼링 메커니즘을 제안한다.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.2
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• pp.117-122
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• 2015

Our research team proposed a flux-offset type fault current limiter as a new limiter. The flux-offset type fault current limiter uses a fault current limit technology based on the flux offset principle of the primary and secondary windings of a transformer. Stable fault current limit characteristics were achieved through a preliminary study. However, it was discovered that the initial fault current was not limited. Therefore, in this paper, a high-speed interrupter and a superconducting element were separately applied to the secondary winding of the flux-offset type fault current limiter and the operating characteristics were comparatively analyzed. In the experiment, when the superconducting element was applied to the secondary winding of the transformer, the initial fault current was limited while the limitation in the operation time was further shortened.

• Electronics and Telecommunications Trends
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• v.18 no.6 s.84
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• pp.1-7
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• 2003

현재 이용되고 있는 이동통신 시스템은 기지국 구축 비용이 높아 무선 인터넷의 이용 요금이 높고 단말기 화면이 작기 때문에 콘텐츠의 제약이 발생하는 등 문제점이 존재하여 초고속 무선인터넷을 제공하기에는 한계가 있다. 그리고, 기존에 사용되고 있는 ISM 대역을 이용한 무선 LAN 기술은 홈 LAN 등에는 가능하나 전파간섭, 좁은 사용영역 등으로 공중서비스 제공에 역시 한계가 있다. 이를 위해서 무선 LAN보다 셀 크기가 크고 중저속의 이동성을 지원하면서 심리스(seamless)한 서비스를 제공할 수 있는 초고속 휴대용 인터넷(High-speed Portable internet: HPi) 시스템이 절실히 요구되고 있다. 이와 같이 급증하는 무선 인터넷 서비스 요구에 효과적으로 대처하기 위한, 휴대성과 이동성이 보장되며 저렴한 요금을 지향하는 새로운 형태의 무선데이터 시스템인 초고속 휴대용 인터넷 시스템 기술에 관련된 국내외 기술 및 표준화 동향을 설명하고, 서비스 특징, HPi 시스템 구조 및 기능 등에 대하여 기술한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1149-1154
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• 2006

HPI(High-speed Portable Internet) system is going to be commercialized before long. Efficient scheduling mechanisms for UGS, rtPS, nrtPS and BE, which are service types of the HPI, are necessary to increase the utilization of wireless channels under the different QoS requirements. In this paper, we develop a simulator which can be used to evaluate the performance of scheduling mechanisms. The advantage of the proposed simulator is that one can simulate diverse situations not changing the simulation model but just setting various parameters.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.233-236
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• 2004

With the internet(World Wide Web) widespread among people after 1995, Information Communication Network, which is basic structure of the internet, is rapidly changing into fiber optics communication. The information conveyed through the internet is being diversified - from simple information based on text to bulky multimedia information such as auido & video data. So the demand for higher speed, hish storage Router is on the crease. This research aims to analyze the general trend of the patent by systematical, multilateral and segmented analysis of the technology's flow and trend, the present technological position of status and the distribution map of the technology by country, technology area using chart and graph.

• Journal of Internet of Things and Convergence
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• v.8 no.6
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• pp.55-63
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• 2022

In recent years, with the rapid development of large and medium-sized urban rail transit in China, the total operating mileage of high-speed railway and the total number of EMUs(Electric Multiple Units) are rising. The system complexity of high-speed EMU is constantly increasing, which puts forward higher requirements for the safety of equipment and the efficiency of maintenance.At present, the maintenance mode of high-speed EMU in China still adopts the post maintenance method based on planned maintenance and fault maintenance, which leads to insufficient or excessive maintenance, reduces the efficiency of equipment fault handling, and increases the maintenance cost. Based on the intelligent operation and maintenance technology of PHM(prognostics and health management). This thesis builds an integrated PHM platform of "vehicle system-communication system-ground system" by integrating multi-source heterogeneous data of different scenarios of high-speed EMU, and combines the equipment fault mechanism with artificial intelligence algorithms to build a fault prediction model for traction motors of high-speed EMU.Reliable fault prediction and accurate maintenance shall be carried out in advance to ensure safe and efficient operation of high-speed EMU.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.3
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• pp.145-154
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• 2006

WiBro (Wireless Broadband Internet) system is going to be 9ot down to commercialization. The high portable internet system is able to be connected to the high-speed internet using 2.3 GHz frequency bandwidth, anytime and anywhere. An effective scheduling for UGS, rtPS, nrtPS and BE requiring different QoS, which are service types of the WiBro, is necessary to increase the efficiency of radio channels that are the limiting resource. This paper researches an uplink scheduling that plays a role in assignment for the radio channels from subscribers to base stations. The suggested scheduling provides priorities with each service type considering QoS of them but reserves some bandwidth for lower priory services. After deciding effective amount of bandwidth for reservation, we suggest analytical result on mean delayed time of packet transmission for each terminal, transmission rate for the data, and capacity for uplink. This research can be used as basic data for the standard in the high portable internet system and as data to predict the capacity of base stations.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.347-353
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• 2005

WiBro (Wireless Broadband Internet) system is going to be commercialized before long. The high portable internet system is abie to be connected to the high-speed internet using 2.3 CHz frequency bandwidth, anytime and anywhere. An effective scheduling for UCS, rtPS. nrtPS and BE requiring different QoS, which are service types of the WiBro, is necessary to increase the efficiency of radio channels that arc the limiting resource. This paper researches an uplink scheduling that plays a role in assignment for the radio channels from subscribers to base stations. The suggested scheduling provides priorities With each service type considering QoS of them but reserves some bandwidth for lower priory services. After deciding effective amount of bandwidth for reservation, we suggest analytical result on mean delayed time of packet transmission for each terminal, transmission rate for the data, and capacity for uplink. This research can be used as basic data for the standard in the high portable internet system and as data to predict the capacity of base stations.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.478-482
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• 2002

Recently, the demand for the optical cable is rapidly glowing because the number of internet user increases and high speed internet data transmission is required. To meet this demand, it is necessary to have a sufficient manufacturing capability for mass and high-quality production. But the present optical cable winding system has some serious problems such that the optical cable of radius (6 mm -40 mm) is often piled up and collapsed usually at the edge of the bobbin in the process of the cable winding. It is often necessary to have an additional operator in order to adjust the cable, which causes the productivity decrease. In order to improve a performance of cable winding system which deals with relatively thick cable( radius : 6 mm -40 mm ), we developed a new guiding system for a high-speed self-align cable winding. First of all, the winding mechanism was analyzed. Synchronization logics for the motions of winding, traversing, and the guiding were created and implemented by using the PLC and guiding system controller in a prototype cable winding system manufactured in the CILS( Computer Integrated Large scale System ) lab. An experimental verification was carried out to validate the logic. Results showed that the winding system with the developed guiding system outperformed in reducing pile-up and collapse in the high-speed winding(up to 300 mm/s) compared with the system without the guiding system.