• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.849-852
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• 2007

In this paper, the high gain and the broadband microstrip patch antenna, which is applicable to 5 GHz band wireless LAN, is designed in order to integrate IEEE 802.11a's detailed standards($a:5.15{\sim}5.25$, $b:5.25{\sim}5.35$, $c:5.725{\sim}5.875$ [GHz]). Designed patch antenna has settled resonance frequency by insert substance(polyurethane: ${\varepsilon}_r=6.5$) between the separated parasitic patch and radiation patch for the purpose of miniaturize. And the form (${\varepsilon}_r=1.03$) were to fix the separated radiation patch and ground plans by air. Designed frequency bandwidth(VSWR 2:1) of the antenna showed broadband characteristic of $4.9[GHz]{\sim}6.1[GHz]$ to about 1.2[GHz]. Also the E-plan and H-plan profit 12[dBi] above, the 3[dB] beamwidth showed the characteristic over the E-plan $30^{\circ}$ and H-plan $60^{\circ}$ to be improved.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.3
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• pp.351-355
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• 2010

The service which is required wide bandwidth is growing in these days, so building up High Speed communication system is being required. The Task Force team of IEEE 802.3ah set the EPON as a standard; next generation subscriber access network. For offering a high quality service, 10G EPON that is changed from 1Gbps uplink downlink bandwidth to 10Gbps is come up. Although Kramer had studied 10G EPON there was a QoS limitation, when load is low, End-to-End maximum delay is increased. This paper is suggesting time synch ronization method, resource reservation method, band width allocation method. We confirmed that 10EPON was able to offer quality service by the result of the OPNET.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5B
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• pp.466-474
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• 2003

In this paper, we develope the simulation model for Ethernet passive optical networks (Ethernet-PON) by using OPNET. Ethernet-PON is an emerging access network technology that provides a low-cost method of deploying optical access lines. The simulator uses a Request/Grant TDMA MAC protocol based on IEEE 802.3ah EFM. It also executes registration, ranging and dynamic bandwidth allocation algorithm by exchanging control packets between OLT and ONUs. We have evaluated for success ratio of initial registration process and delay of late registration process. We also have simulated for dynamic TDMA protocol and static TDMA protocol in terms of channel utilization and queueing delay. We expect that this simulator can help to determine various parameters which are considered for designing Ethernet-PON system.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.6
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• pp.39-49
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• 2013

In recent, many countries and research institutes have been studying how to construct the high-speed subscriber access network. Task Force team of IEEE 802.3ah has accomplished the standardization of EPON which is the next generation subscriber access network. EPON doesn't still have the bandwidth enough to support the new service(e.g various multimedia service) which demands the high bandwidth. For these new multimedia services,10G EPON is the next generation subscriber access network which expanded the up-down bandwidth range of 1G EPON 10 times in order to support demanding high bandwidth. We have proposed the model which can accommodate IEEE 802.1 AVB traffics smoothly in 10G EPON and suggesting the Intra-ONU scheduling model which makes this model operate effectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3A
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• pp.223-232
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• 2004

In this paper we propose the hierarchical-based dynamic bandwidth allocation algorithm for multi-class services in Ethernet-PON. The proposed algorithm consists of the high level scheduler in OLT and the low level scheduler in ONU. The hierarchical architecture is able to provide scalability and resource efficiency in Ethernet-PON which has the distributed nature of the scheduling domain, with queues and the scheduler located at a large distance from each other. We also propose three dynamic bandwidth allocation algorithms for the low level scheduler: Proportional Allocation algorithm, Maximum Request First Allocation (MRFA) algorithm and High Priority First Allocation (HPFA) algorithm. We implement the Ethernet-PON standardized in the IEEE 802,3ah using OPNET. We also evaluate and analyze the performance for the proposed algorithms in terms of channel utilization, queuing delay and the amount of remainder.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1B
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• pp.1-10
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• 2003

An EPON which is going on standardization in IEEE 802.3ah, is tree topology consists of a OLT and multiple ONU using passive optical components, so this network is susceptible to variable security threats - eavesdropping, masquerading, denial of service and so on. In this paper, we design a security protocol supporting authentication and confidentiality services in MAC layer in order to prevent these security threats and to guarantee secure data exchange The designed security protocol introduce public-key based authentication and key management protocols for efficient key management, and choose Rijndael algorithm, which is recent standard of AES, to provide the confidentiality of EPON Proposed authentication and key management protocols perform authentication and public-key exchange at a time, and are secure protocols using derived common cipher key by exchanging public random number To implement the designed security protocol, we propose the procedures of authentication and public-key exchange, session key update, key recovery. This proposed protocol is verified using unknown session key, forward secrecy, unknown key-share, key-compromise impersonation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.5
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• pp.106-121
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• 2008

In this paper, we proposed and designed the protocol for energy efficiency and the center of data aiming at the design of a Multi Location Awareness System that recognizes a shadow site in parking and tunnel, which stands on the basis of CSS(Chirp Spread Spectrum) method using ISM Band of IEEE 802.15.4a that aware close location with wireless RF only. As a result of the protocol measurement, it displays the observation errors of less than 15cm, the data error rate of less than 5%, and can implement the Multi Location Awareness System with maximum length of life for 13.5 days using battery of 3V(1500 mAh).

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2687-2689
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• 2003

국내 LNG/LPG 누출을 관리할 수 있는 유무선 복합 종합관리시스템을 개발하였다. 이 시스템은 무선가스누출 탐지 및 제어부, 유선가스누출 탐지 및 제어부, 종합관리 시스템부로 구성되며, 특징으로는 무선가스누설 제어부 : 통신속도 1200bps, 유선가스누설 제어부 : 내부통신속도 9600 bps, IEEE 802 양방향 통신 방식, 최대전송속도 25 Mbps, 군 관리기능(server to server). 자체진단기능 등이다. 본 시스템을 가스공사 연구개발원 내에 운영되고 있는 CNG 및 LCNG 충전에 설치 운영하여 성능시험을 거친 결과, 현재까지 기존의 외국제품과 동등한 성능을 보이고 있으며 단가면에서도 2/3정도로 경쟁력을 가지고 있다. 보다 장기적인 현장적용 시험을 통해 성능 및 장기안정성 등이 확립되면 국내시장뿐만 아니라 수출을 통한 국제시장 점유도 기대할 수 있을 것이다.

• ETRI Journal
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• v.28 no.1
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• pp.9-16
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• 2006

In this paper, we analyzed and measured the electrical crosstalk characteristics of a 1.25 Gbps triplexer module for Ethernet passive optical networks to realize fiber-tothe-home services. Electrical crosstalk characteristic of the 1.25 Gbps optical triplexer module on a resistive silicon substrate should be more serious than on a dielectric substrate. Consequently, using the finite element method, we analyze the electrical crosstalk phenomena and propose a silicon substrate structure with a dummy ground line that is the simplest low-crosstalk layout configuration in the 1.25 Gbps optical triplexer module. The triplexer module consists of a laser diode as a transmitter, a digital photodetector as a digital data receiver, and an analog photodetector as a cable television signal receiver. According to IEEE 802.3ah and ITU-T G.983.3, the digital receiver and analog receiver sensitivities have to meet -24 dBm at $BER=10^{-12}$ and -7.7 dBm at 44 dB SNR. The electrical crosstalk levels have to maintain less than -86 dB from DC to 3 GHz. From analysis and measurement results, the proposed silicon substrate structure that contains the dummy line with $100\;{\mu}m$ space from the signal lines and 4 mm separations among the devices satisfies the electrical crosstalk level compared to a simple structure. This proposed structure can be easily implemented with design convenience and greatly reduce the silicon substrate size by about 50 %.

• ETRI Journal
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• v.26 no.4
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• pp.321-331
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• 2004

In this paper, we propose a new dynamic bandwidth allocation (DBA) algorithm for multimedia services over Ethernet PONs (passive optical networks). The proposed algorithm is composed of a low-level scheduler in the optical network unit (ONU) and a high-level scheduler in the optical line terminal (OLT). The hierarchical DBA algorithm can provide expansibility and efficient resource allocation in an Ethernet PON system in which the packet scheduler is separated from the queues. In the proposed DBA algorithm, the OLT allocates bandwidth to the ONUs in proportion to the weight associated with their class and queue length, while the ONU preferentially allocates its bandwidth to queues with a static priority order. The proposed algorithm provides an efficient resource utilization by reducing the unused remaining bandwidth caused by the variable length of the packets. We also define the service classes and present control message formats conforming to the multi-point control protocol (MPCP) over an Ethernet PON. In order to evaluate the performance, we designed an Ethernet PON system on the basis of IEEE 802.3ah "Ethernet in the first mile" (EFM) using OPNET and carried out simulations. The results are analyzed in terms of the channel utilization, queuing delay, and ratio of the unused remaining bandwidth.