• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1998년도 학술대회
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• pp.177-180
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• 1998

본 논문에서는 차세대 이동통신의 다중 접속 방식으로 제안되고 있는 3G IS-95 Multi-Band CDMA중 5MHz 대역폭을 갖는 시스템의 순방향 링크에 대한 SPW 구현 및 검증을 수행하였다. 구현된 시스템은 3개의 반송파를 가지는 5HMz 대역폭의 기본 채널(Fundamental Channel)용 기지국 변조기와 차세대 이동통신용으로 제안된 채널 환경, 그리고 이동국용 복조기로 구성되었다. 각 기능 블록들의 동작 상태와 각 단계에서의 신호 변화 및 전송되는 정보의 복원 과정에 대한 SPW 검증이 SNR(Eclo=-14.08dB에서 이루어졌다.

• Progress in Superconductivity
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• 제1권2호
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• pp.141-145
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• 2000

Different twist pitches of multi filamentary BSCCO 2223 tapes using high resistivity sheath were fabricated to investigate the effect of twist pitches on the microstructure and critical current property. A conductor with a high resitstivity matrix is possible to allow larger twist pitch for reducing ac losses and reduce eddy current losses simultaneously. The $J_{ct}$ values of 10 mm and 5 mm twisted tapes drop faster than that of untwisted and 20 mm twisted tapes under increasing magneticfield, especially in low field regime (0 $\sim$ 0.03 T). It suggests that weak links in the former are more serious than in the latter, which is in accordance with the microstructure analysis.

• 소성∙가공
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• 제18권3호
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• pp.229-235
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• 2009

This paper covers finite element simulations to evaluate the terminal crimping process of automobile electrical connector. Crimping is a classical technology process to ensure the electrical and the mechanical link between a wire and a terminal. Numerical modeling of the process is helpful to choose and to optimize the dimensions of the crimping part of the connector. In this paper, we discuss a 2D simulation of the crimping process, using explicit finite element methods (ABAQUS/Explicit) and we compare the results with experimental data from the industrial process of crimping (crimping height, crimping width and compressibility). The explicit method is preferred for the modeling of multi-contact problems, in spite of the quasi-static process of crimping. As compared with CAE analysis, a performance improvement makes certain of the truth of the matter.

• 한국정밀공학회지
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• 제15권8호
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• pp.165-173
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• 1998

In this paper, a motion control algorithm is developed by using fuzzy control technique, which makes a robot arm avoid unexpected obstacles when the robot is moving from the start to a goal posture. During the motion, if there exist no obstacles the robot arm moves along the pre-defined path. But if some obstacles are recognized and close to the robot arm, a fuzzy controller is activated to adjust the path of the robot arm. To show the feasibility of the developed algorithm, numerical simulations and experiments are carried out. In the experiments, redundant planar robot arms are considered for the collision avoidance test, and it was proved that the developed algorithm gives good collision avoiding performance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.746-751
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• 2002

This purpose of this study was to design the effect of recovering of a hand amputees by myoelectronic hand. It was designed with 2 degree of freedom in tile laboratory. Myoelectronic hand had only one degree of freedom and one movement until now. Also this myoelectronic hand had multi-joint system. Myoelectronic hand data was obtained by measuring hand and data was applied when it was designed myoelectronic hand. PID controll of myoelectronic hand was used to it. Displacement control was applied the first link of finger. Experiment was accomlkished in Tip grasp, power grasp and Hook grasp modes. Displacement controll was good in low frequency. Velocity control was applied to each mode. This myoelectronic hand with a hand amputees could do some jobs such as grasping materials. Further studies were needed to evaluate the effect of a myoelectronic hand with more precise laboratory equipment.

• 천문학회지
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• 제34권4호
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• pp.297-299
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• 2001

We have constructed the foundations to a series of theoretical diagnostic methods to probe the jet phenomenon in young stars as observed at various optical forbidden lines. We calculate and model in a self-consistent manner the physical and radiative processes which arise within an inner disk-wind driven magneto centrifugally from the circumstellar accretion disk of a young sun-like star. Comparing with real data taken at high angular resolution, our approach will provide the basis of systematic diagnostics for jets and their related young stellar objects, to attest the emission mechanisms of such phenomena. This work can help bring first-principle theoretical predictions to confront actual multi-wavelength observations, and will bridge the link between many very sophiscated numerical simulations and observational data. Analysis methods discussed here are immediately applicable to new high-resolution data obtained with HST and Adaptic Optics.

• 한국통신학회논문지
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• 제27권6B호
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• pp.593-600
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• 2002

The reverse link signal power required for multimedia traffic in multipath faded single-code (SC-) and multi-code CDMA (MC-CDMA) systems is investigated. The effect of orthogonality loss among multiple spreading code channels is herein characterized by the orthogonality factor. The required signal power in both the CDMA systems is then analyzed in terms of the relative required signal power ratio of data to voice traffic. The effect of varying system parameters including spreading bandwidth, the of orthogonality factor, and the number of spreading codes are examined. Analytical results show that MC-CDMA users transmitting only a single traffic type require significantly more power than SC-CDMA users with only a single traffic type. On the other hand, MC-CDMA users transmitting multimedia traffic require power levels approximately identical to SC-CDMA users with multimedia traffic. The results can be used in the design of radio resource management (e.g., power allocation) scheme for wireless multimedia services.

• Journal of the Optical Society of Korea
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• 제12권2호
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• pp.69-78
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• 2008

EPONs are a low cost, high speed solution to the bottleneck problem of broadband access networks. To support point-to-point and shared LAN emulation, EPONs use the multi-point control protocol (MPCP), which uses logical link identification (LLID) forframe tagging and filtering between the OLT and ONUs. In this paper, ONU-based multicast or multiple shared LAN emulation for IPTV services is proposed using logical group identification (LGID). Using ONUbased VLAN services, EPONs can support separate and secure connections between providers and subscribers in a simple manner. Also, differentiated IPTV channel packages can be delivered through EPONs by implementing ONU-based VLAN and IGMP snooping mechanisms.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
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• pp.364-367
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• 2004

This paper presents the flight software of KoDSat (KSLV-l Demonstration Satellite) which performs demonstrating the KSLV-l (Korea Space Launch Vehicle-l)'s satellite launch capability. The KoDSat Flight Software executes in a single-processor, multi-function flight computer on the spacecraft, the OBC (On Board Computer). The flight software running on the single processor is responsible for all real-time processing associated with: processor startup and hardware initialization, task scheduling, RS422 handling function, command and data handling including uplink command and down-link telemetry, attitude determination and control, battery state of charge monitoring and control, thermal control processing.

• ETRI Journal
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• 제24권2호
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• pp.69-81
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• 2002

This paper reviews the existing research activities on signaling and control procedures for IP over optical networks. We focus on the IP-centric signaling and control architecture based on the generalized multi-protocol label switching (GMPLS) protocol and analyze various scenarios and technical issues for deploying the IP over an optical network. We analyze the signaling and operations and administration and maintenance requirements for integrating an IP network and an optical network in order to cope with the high bandwidth and poor resource granularity of the optical network, including the optical cross-connect system. On the basis of network architecture and a reference configuration model, we investigate the GMPLS-based control architecture and interconnection model appropriate for controlling IP bandwidth and optical lambda resources. The signaling and control procedure based on GMPLS on optical user-network interface and network-network interface are comparatively investigated to provide the optical lightpath. We also study protection and restoration procedures to protect link failure when it applies to generalized MPLS signaling.