• The Journal of Korean Institute of Communications and Information Sciences
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• 제35권1A호
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• pp.16-24
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• 2010

High Speed Uplink Packet Access(HSUPA) is a WCDMA Release 6 technology which corresponds to High Speed Downlink Packet Access(HSDPA). Node B Supports fast scheduling, Hybrid ARQ(HARQ), short Transmission Time Interval(TTI) for high rate uplink packet data. It is very important to detect Iub congestion to improve end user's Quality of Service(QoS). This paper proposes Node B Congestion Detection(BCD) mechanism and suggests to use the hybrid of Transport Network Layer(TNL) congestion detection and BCD. It is shown that HSUPA user throughput performance can be improved by the proposed method even with small Iub bandwidth.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.355-355
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• 2000

The position control accuracy of a robot manipulator is significantly deteriorated when a long arm robot is operated at a high speed. This paper presents a very simple sliding mode control which eliminates multiple mode residual vibration in a 개bot manipulator. The neural network is used to avoid that sliding mode condition is deviated due to the change of system parameter and disturbance. This paper is suggested control system which designed by sliding mode controller using neural network. The effectiveness of proposed scheme is demonstrated through computer simulation.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.233-236
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• 2005

Our country compares with advanced nations by supply of super high speed network and information communication infra construction has gone well very. Many people by extension of on-line transaction and various internet services can exchange, or get information easily in this environment. But, virus or poisonous information used to Cyber terror such as hacking was included within such a lot of information and such poisonous information are threatening national security as well as individual's private life. There were always security and speed among a lot of items to consider networks equipment from these circumstance to now when develop and install in trade-off relation. In this paper, we present a high speed VPN Acceleration Board(VPN-AB) that balances both speed and security requirements of high speed network environment. Our VPN-AB supports two VPN protocols, IPsec and SSL. The protocols have a many cryptographic algorithms, DES, 3DES, AES, MD5, and SHA-1, etc.. The acceleration board process data packets into the system with In-line mode. So it is possible that VPN-AB processes inbound and outbound packets by 10Gbps. We use Nitrox-II CN2560 security processor VPN-AB is designed using that supports many hardware security modules and two SPI-4.2 interfaces to design VPN-AB.

• Proceedings of the KIEE Conference
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1228-1229
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• 2011

A novel approach has been promoted for FNN ship controllers. An Electro-hydraulic governor has been widely adopted to the ship speed control of propulsion marine diesel engines for a long time, it was very difficult for Electro-hydraulic governor to regulate the speed of high power engine with long stroke at low speed and low load, because of the jiggling phenomena by rough fluctuation of rotating torque and the hunting phenomena by long dead time occurred in fuel combustion process in the engine cylinder. This paper provides an efficient way for improving control performance by FNN controller. An RBF neural network and GA optimization are employed in a fuzzy neural controller to deal with the nonlinearity, time varying and uncertain factors, the rule base and membership functions can be auto-adjusted by GA optimization. The parameters of neural network can be decreased by using union-rule configuration in the hidden layer of the network. The performance of controller is evaluated by the system simulation using simulink tools.

• IEIE Transactions on Smart Processing and Computing
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• 제3권4호
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• pp.212-220
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• 2014

The current cellular communications are optimized for low mobility users, meaning that their performance is degraded at high speed. Therefore, passengers in a high-speed train experience very poor radio link quality due to the significantly large number of simultaneous handovers. In addition, wireless data traffic is expanding exponentially in trains, subways and buses due to the widespread use of smartphones and mobile devices. To solve the inherent problem of cellular communication networks and meet the growing traffic demand, this paper proposes the mobile hotspot network of a millimeter-wave communication system as a mobile wireless backhaul. This paper describes the physical layer design of uplink and downlink in the proposed system, and the performances of uplink and downlink are evaluated under Rician fading channel conditions. The implemented baseband prototype of the proposed millimeter-wave communication modem is presented. This system can provide a Gbps data rate service in high-speed trains carrying hundreds of wireless Internet users.

• Proceedings of the Korea Contents Association Conference
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• 한국콘텐츠학회 2003년도 춘계종합학술대회논문집
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• pp.474-479
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• 2003

We discussed the usage of a radio resource, the spectrum allocation and the trends of policy about 5㎓ band in other countries, We studied about the technical regulation on high speed wireless access system and the spectrum allocation of ISM bard in 5㎓ bard for other countries. We also analyzed the efficient use of radio resource, the method of frequency sharing and the calculation of spec01m requirement in noel to progress the high speed wireless access system In addition We proposed the schemes of domestic spectrum allocation for high speed wireless access system at 5㎓ band

• Journal of Communications and Networks
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• 제9권4호
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• pp.394-401
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• 2007

High speed all optical network is a viable option to satisfy the exponential growth of internet usage in the recent years. Optical networks offer very high bit rates and, by employing technologies like internet protocol over wavelength division multiplexing(IP-over-WDM), these high bit rates can be effectively utilized. However, failure of a network component, carrying such high speed data traffic can result in enormous loss of data in a few seconds and persistence of a failure can severely degrade the performance of the entire network. Designing IP-over-WDM networks, which can withstand failures, has been subject of considerable interest in the research community recently. Most of the research is focused on the failure of optical links in the network. This paper addresses the problem of designing IP-over-WDM networks that do not suffer service degradation in case of a single link failure. The paper proposes an approach based on the framework provided by a recent paper by M. Kurant and P. Thiran. The proposed approach can be used to design large survivable IP-over-WDM networks.

• Journal of Internet Computing and Services
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• 제5권4호
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• pp.23-33
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• 2004

In this paper, we propose a novel traffic measurement based detection of network attack symptoms on high speed Internet backbone links. In order to do so, we characterize the traffic patterns from the normal and the network attacks appeared on Internet backbone links, and we derive two efficient measures for representing the network attack symptoms at aggregate traffic level. The two measures are the power spectrum and the ratio of packet counts to traffic volume of the aggregate traffic. And, we propose a new methodology to detect networks attack symptoms by measuring those traffic measures. Experimental results show that the proposed scheme can detect the network attack symptoms very exactly and quickly. Unlike existing methods based on Individual packets or flows, since the proposed method is operated on the aggregate traffic level. the computational complexity can be significantly reduced and applicable to high speed Internet backbone links.

• Journal of Electrical Engineering and information Science
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• 제2권6호
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• pp.64-73
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• 1997

Network technology has been developed for very high-speed networking and multimedia data whose characteristics are the continuous and bursty transmission as well as a large amount of data. With this trend users wish to view the information about the application services as well as network devices and system hardware. However, it is rarely available for the users the information of performance or faults of the application services. Most of information is limited to the information related network devices or system hardware. Furthermore, users expect the best services without knowing the service environments in the network and there is no good way of delivering the service related problems and fault information of application services in a high speed network yet. In this paper we present a web-based application management system that we have developed for the past year. It includes a method to build an agent system that uses an existing network management standards, SNMP MIB and SNMP protocols. The user interface of the system is also developed to support visualization effects with web-based Java interface which offers a convenient way not only to access management information but also to control networked applications.

• The KIPS Transactions:PartC
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• 제8C권3호
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• pp.335-344
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• 2001

최근 인터넷 환경이 반도체, 광통신 그리고 차세대 인터넷 기술의 발달로 고성능화 되어가고 있다. 따라서 고성능 인터넷을 위한 TCP의 성능 향상 연구가 매우 중요해졌다. 그러나 기존 TCP는 수신위도 버퍼의 물리적 크기에 의하여 최대 전송 성능과 대역폭 탐색 기능이 제한을 받는 구조적인 문제점을 갖고 있다. 본 논문에서는 이를 해결하기 위하여 수신 호스트에 가상 윈도 개념을 도입하였다. 이는 송신 호스트가 RTT 동안 균일하게 세그먼트를 분산시켜서 패킷을 전송할 때 세그먼트 간격 시간 동안 수신 호스트의 처리 능력을 가상윈도로 나타내는 것이다. 따라서 가상 윈도의 크기는 수신 호스트의 성능에 비례하기 때문에 수신 호스트가 고성능일 경우 TCP의 전송 능력 성능이 더 높아질 수 있다. 초고속 인터넷일 경우 제안 알고리즘이 기존 TCP보다 전송능력에 있어 1.5∼5배 개선되는 것을 네트워크 시뮬레이션인 NS2를 이용하여 확인하였다.