• 전기학회논문지
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• 제56권5호
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• pp.926-932
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• 2007

A recently developed methods for on-site calibration of the current transformer (CT) comparator system have been reviewed in the paper. The method utilizes several traveling standards, which consist of the CT, non-reactive standard resistors, wide ratio error CT, and shunt resistors. The traveling CT is used for absolute evaluation of a standard CT belonging to industry. The non-reactive standard resistors and a wide ratio error CT are used for the linearity check of errors in the current comparator. The shunt resistors are used for evaluation of CT burden of industry.

• 대한기계학회논문집
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• 제17권11호
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• pp.2655-2663
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• 1993

In order to evaluate the relative significance of tolerance management of various elements in a VHS VTR tape transport system, the effect of geometric variations of the elements from standard design values on the tape traveling path is studied. The tape is modeled as a string and each element in the tape transport system is modeled as a cylinder whose radius, position vector and orientation vector are specified. An numerical algorithm is proposed to find the coordinates of tape entry points and tape exit points for the elements from which the tape traveling path can be completely described. By using the suggested algorithm, an error sensitivity analysis of tape traveling path due to the geometric variations of tape transport elements is performed for a particular model in the market and the elements demanding relatively strict tolerance management are identified.

• 전기학회논문지
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• 제56권7호
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• pp.1268-1274
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• 2007

A recently developed methods for the on-site calibration of the voltage transformer (VT) comparator system have been reviewed in the paper. The method utilizes the several traveling standards consisting of the VT, the non-reactive standard resistors, the wide ratio error VT, and the decade resistors. The VT is used for the absolute evaluation of a standard VT belonging to the industry. The non-reactive standard resistor and wide ratio error VT are used for the linearity check of errors in the voltage comparator of the industry. The decade resistors are used for evaluation of a VT burden of the industry.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권3호
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• pp.255-265
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• 2012

This paper presents a 15-GHz multiphase rotary traveling-wave voltage-controlled oscillator (RTW VCO) where a shielded coplanar stripline (CPS) is exploited to provide better shielding protection and lower phase noise at a moderate cost of characteristic impedance and power consumption. Test chips were implemented in a standard 90-nm CMOS process, demonstrating the measured results of 2-GHz frequency tuning range, -11.3-dBm output power, -109.6-dBc/Hz phase noise at 1-MHz offset, and 2-ps RMS clock jitter at 15 GHz. The chip core occupies the area of $0.2mm^2$ and dissipates 12 mW from a single 1.2-V supply.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.675-676
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• 2008

The computer based three phase power analysing system has been developed as a traveling standard for onsite power calibration. The system is utilized with digital-to-analog converts which were synchronized each other. Using digital signal processing technique the software has been developed to calculate power parameters. The calibration system is fully traceable to national standard system and, accuracy allows the calibration of industrial power measurement systems.

• Journal of electromagnetic engineering and science
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• 제15권4호
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• pp.224-231
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• 2015

A comparison of the antenna parameters for R-band (1.7-2.6 GHz) and S-band (2.6-3.95 GHz) standard gain horn antennas has been performed by the Korea Research Institute of Standards and Science (KRISS), together with seven domestic participants from private companies and public institutions. Its purpose, as a proficiency test program of the 'Antenna Measurement Club' of KRISS, was to check equivalences in antenna parameter measurements between KRISS and the participants, particularly in the R-/S-band, to support antenna manufacturers and end users in Korea. The measurement parameters of this comparison are the power gain, radiation pattern, and reflection coefficient of the traveling standards for R-/S-band pyramidal standard gain horn antennas. The comparison used a gain comparison method and an extrapolation method to measure the power gain of the two traveling standards; the radiation patterns were measured in the far-field region of the transmitting and receiving antennas.

• 한국공간구조학회논문집
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• 제5권1호
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• pp.65-71
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• 2005

This research analyzed dynamic responses of the preflex railroad bridge. Vertical deflection and acceleration induced by operating train loads and test train loads were measured. Deflection of bridge by train traveling satisfies deflection limitation regulation (L/800) about the concrete bridge, but compare with UIC standard, vibration acceleration happened fairly greatly. Also test result show that acceleration receives greatly effect about the speed than deflection. It must discuss about vibration acceleration problems for speed elevation hereafter.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1021-1027
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• 2004

This research analyzed dynamic responses of the preflex railroad bridge. Vertical deflection and acceleration induced by operating train loads and test train loads were measured. Deflection of bridge by train traveling satisfies deflection limitation regulation (L/800) about the concrete bridge, but compare with UIC standard, vibration acceleration happened fairly greatly. Also test result show that acceleration receives greatly effect about the speed than deflection. It must discuss about vibration acceleration problems for speed elevation hereafter.

• Journal of Communications and Networks
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• 제10권4호
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• pp.412-421
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• 2008

We observe simultaneous transmission of relay stations (RSs) allowed in current IEEE 802.16j draft standard for multi-hop relay networks may involve severe interference among the RSs, hence leading to throughput degradation. Allowing only 1/3 of the RSs to simultaneously transmit instead of 1/2 RSs as in the current draft standard reduces the interference but results in reduced throughput. To remedy this problem, we devise schemes to incorporate network coding at link-layer level (decode-and-forward) into the simultaneous transmission of RSs. Data movement is rearranged to maximize coding gain. Formula is derived to dictate exact movement of packets traveling between base station (BS) and mobile stations (MSs) via intermediate RSs. The frame structure in the current IEEE 802.16j draft standard does not allow broadcast needed for network coding. We devise a new frame structure which supports the broadcast. A new R-MAP (pointers to the burst data) is introduced to implement the broadcast. Since our new frame structure is used only for BS to RS or RS to RS communication, our schemes retain backward compatibility with legacy MSs based on IEEE 802.16e standard. Simulation based on simple configuration of RSs shows considerable improvement in terms of system throughput and round trip delay. For a 4-hop relay network with 1 BS and 4 RSs with symmetric traffic in uplink (UL) and downlink (DL), throughput is improved by 49% in DL and by 84% in UL traffic compared with IEEE 802.16j draft standard under the assumption that omni-directional antennae are used in BS and RSs.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2002년도 추계기술심포지움논문집
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• pp.115-121
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• 2002

In this research we have investigated the characteristics of ultra thin $HfO_2 /SiON$stack structure films using several analytical techniques. SiON layer was thermally grown on standard SCI cleaned silicon wafer at $825^{\circ}C$ for 12sec under $N_2$O ambient. $HfO_2 /SiON$$_4$/$H_2O$ as precursors and $N_2$as a carrier/purge gas. Solid HfCl$_4$was volatilized in a canister kept at $200^{\circ}C$ and carried into the reaction chamber with pure $N_2$carrier gas. $H_2O$ canister was kept at $12^{\circ}C$ and carrier gas was not used. The films were grown on 8-inch (100) p-type Silicon wafer at the $300^{\circ}C$ temperature after standard SCI cleaning, Spectroscopic ellipsometer and TEM were used to investigate the initial growth mechanism, microstructure and thickness. The electrical properties of the film were measured and compared with the physical/chemical properties. The effects of heat treatment was discussed.