• Proceedings of the KSME Conference
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• 2004.04a
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• pp.804-809
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• 2004

This paper introduces a link-type tracked vehicle which is developed for demining operations. The vehicle consists of three parts - front frame, rear frame and body. The front frame is connected to the rear frame by a rotational passive adaptation mechanism which is a driving mechanism of the vehicle. Additionally, the demining system which is adaptable to mobile robot is developed to clear small Anti-Personnel(AP) mines with inexplosive method. In other words, assembled rakes unearth mines by their opposite rotation to the direction of the robot. Finally, the motions of demining rakes and design parameters of the demining system are analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1569-1574
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• 2003

최근에 VOD, HDTV, 라이브 스트리밍 등의 서비스가 늘어나면서 가입자들은 광대역 서비스를 요구하고 있다. 이를 가입자에게 제공하기 위해서는 광대역폭을 지원할 수 있는 FTTH(Fiber to The Home)의 실현이 필수적이며, FTTH의 고비용과 설비 문제를 해결하기 위한 대안으로 PON(Passive Optical Network)이 부상하고 있다. PON은 네트워크를 시스템이 아닌 소자로 구성해, 일정거리까지는 하나의 광 회선을 설치하고 스플리터를 중심으로 여러 개로 회선을 분배하는 것이다. 이 또한 스플리터의 한계로 분배할 수 있는 회선이 제한적이며, 이를 해결하기 위한 방법으로 WDM(Wavelength Division Multiplexing)-PON이 고려되고 있다. 이에 본 논문에서는 WDM-PON에 적용할 수 있는 Ethemet 기반의 광 송수신 채널 유닛을 설계하였다. 채널 유닛은 1000BASE-T Ethernet 신호를 입력받아 파장별 DFB-LD에 직접 변조하는 방식을 사용하여 구현하였다

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.8
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• pp.1004-1013
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• 1999

This paper considers the transient stability problem of power system. The power system model is given as interconnected system consisting of many machines which are described by swing equations. We design a transient stability controller using passivity and neural network. The structure of the neural network controller is derived using a filtered error/passivity approach. In general, a neural network cannot be guaranteed to be passive, but the weight tuning algorithm given here do guarantee desirable passivity properties of the neural network and hence of the closed-loop error system. Moreover proposed controller shows good robustness by simulation for uncertainties in parameters, which can not be shown in the speed gradient method proposed by Fradkov[3,7].

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.608-610
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• 2003

Ethernet PON(Passive Optical Network)에서 핵심 기술 중의 하나인 MAC(Media Access Control) 프로토콜은 ONU(Optical Network틴nit)들이 상향으로 트래픽을 전송할 때 공유되어 있는 링크상의 충돌을 방지하고, 효율적인 대역폭을 할당하기 위한 스케줄링 알고리즘을 포함하고 있다. 본 논문에서는 차세대 가입자 망인 Ethernet PON에서 상향으로의 대역폭 부족을 개선하기 위하여, n개의 파장을 사용한 가변 슬롯 할당 TDMA(Time Division Multiple Access) 방식의 MAC 프로토콜을 제안한다. 이를 검증하기 위하여 OPNET 시뮬레이션 도구를 이용해 Ethernet PON 모델을 설계하고 시뮬레이션 한다.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.251-258
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• 1999

The vibration control of bridge is studied considering the vibration characteristics of the Korean-type high-speed railway bridge. Fast nonlinear analysis is adopted as time integration method and the bridge and the train are modeled by FEM and sequentially moving constant forces respectively. Additional damping mechanism is indispensable to the Korean-type high-speed railway bridge because resonance vibration is excited under the maximum design speed. The optimal position and capacity of the damper is studied through the parametric studies, Transient vibration of the bridge is effectively controlled by such additional dampers which means that dampers play a role as structural damping. And also the maximum response of the bridge is reduced. Therefore it is verified that the increase of expected service life and the improvement of serviceability can be obtained through dampers.

• Korean Institute of Interior Design Journal
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• v.20 no.6
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• pp.254-261
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• 2011

The purpose of this study was to investigate the characteristic as to how the Indonesian traditional space is expressed in a contemporary space. As for the study method, We visited 12 Indonesian restaurants in Jakarta from Oct. 16 to Oct. 20, 2010 for a case study. The study result is presented as follows: First, as a factor of facade components, the roof part revealed its identity as a Joglo structure. Walls, windows and doors reflected Indonesian tradition, or were transformed in passive or aggressive ways. Second, as a factor of interior space components, ceilings were predominantly designed by reflecting a structural exposure ceiling or Tumpang Sari as it was or by passively transforming them; Interior walls, windows and doors were transformed in aggressive ways. Third, regarding the factors of interior decoration components, traditional furniture was not used, but instead, furniture with contemporary form and local materials were dominently used, and traditional accessaries were used as they were. Therefore, in the case of designing spatial componentss in Indonesian restaurants located in Jakarta, roofs and ceilings, floors, furniture, and accessaries reflected Indonesian tradition, or were passively transformed, whereas walls, windows, doors, and some ceilings aggressively reflected modernized tradition so that they were formed in harmony with traditional and contemporary styles.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.8
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• pp.1263-1268
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• 2008

In this paper, the low noise power amplifier for GaAs FET ATF-10136 is designed and fabricated with active bias circuit and self bias circuit. To supply most suitable voltage and current, active bias circuit is designed. Active biasing offers the advantage that variations in the pinch-off voltage($V_p$) and saturated drain current($I_{DSS}$) will not necessitate a change in either the source or drain resistor value for a given bias condition. The active bias network automatically sets a gate-source voltage($V_{gs}$) for the desired drain voltage and drain current. Using resistive decoupling circuits, a signal at low frequency is dissipated by a resistor. This design method increases the stability of the LNA, suitable for input stage matching and gate source bias. The LNA is fabricated on FR-4 substrate with active and self bias circuit, and integrated in aluminum housing. As a results, the characteristics of the active and self bias circuit LNA implemented more than 13 dB and 14 dB in gain, lower than 1 dB and 1.1 dB in noise figure, 1.7 and 1.8 input VSWR at normalized frequency $1.4{\sim}1.6$, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2367-2374
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• 2011

Today's digital broadcasting services based on DVB-SI standard are provided a two-way broadcast. However, using the power of STB if the user does not use a waste of time spent on standby power is becoming a serious problem. Accordingly, for energy savings both at home and abroad to actively promote green policies, but highly functional STB, the internal software to automatically update the appropriate scheduling techniques are not shown, power usage does not meet the standard can. Therefore, In this paper We analyze the current STB technology and the problems, as proper use of power to the standard STB design scheme and the automatic software installation method of operation is presented.

• Journal of Korea Multimedia Society
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• v.7 no.10
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• pp.1421-1435
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• 2004

When various work was given from user, the existing mobile agent model migrated from node to node and process the work at the point that much traffics according to passive routing schedule are happened, until it makes service the work result, time cost of round work process for the distributed nodes are increased. Therefore, the existing agent systems need migration method to solve the problems of agent size increment or a lack of interoperability among agent systems. To solve these problems in this thesis, we design and implement an CORBA-based Mobile Agent Model(CMAM) for the efficient work process into the distributed nodes, when the mobile agents are migrated among the nodes, using an optimal path search by sensing of network traffic.

• 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 %.