• Journal of Astronomy and Space Sciences
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• v.17 no.2
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• pp.309-316
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• 2000

KOMPSAT-2 will carry MSC(Multi-Spectral Camera) which provides 1m resolution panchromatic and 4m resolution multi-spectral images at the altitude of 685km sun-synchronous mission orbit. The mission operation of KOMSPAT-2 is to provide the earth observation using MSC with nadir pointing. KOMPSAT-2 will also have the capability of roll/pitch tilt maneuver using reaction wheel of satellite as required. In order to protect MSC from thermal distortion as well as direct sunlight, MSC shall be operated within the constraint of sun incidence angle. It is expected that the sunlight will not violate the constraint of sun incidence angle for normal mission operations without roll/pitch maneuver. However, during roll/pitch tilt operations, optical module of MSC may be damaged by the sunlight. This study analyzed sun incidence angle of payload using KOMPSAT-2 AOCS (Attitude and Orbit Control Subsystem) Design and Performance Analysis Soft ware for KOMPSAT-2 normal mission operations.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.36-40
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• 2013

Recently, electronic equipments become smaller, more functional, and more complex than before. As these trends, MLC(multi-layer ceramic) circuit has been emerged to a promising technology in semiconductor inspection industry. Especially, multi-layer ceramic which is consisted of many fine-pitch multi-hole is used to produce a semiconductor inspection unit. The hole is processed by UV laser. But, working conditions are changed all the time. Therefore real time measurement of fine-pitch multi-hole is very important method for ensuring performance. In this paper we found the best method for illuminating and auto focusing. And, we verified our equipment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.96-102
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• 2003

Today, stage technology is developing highly by application of digital computer. Performance is composed of audio/video and acoustic technology takes very important position in field of stage technology. Generally speaking, four factors of sound are loudness, pitch, sound timbre and duration. Loudness depends on sound pressure level, yet partly related with spectrum and dulation. Pitch depends mainly on frequence and have a relation with sound pressure and duration. sound timbre depends strongly on spectrum and have a relation with frequence. In this paper, I designed a multi-microphone system which can used in broadcasting and performance stage with vicboss 200MHz-VHF wireless microphone and vicboss 900MHz-VHF wireless microphone. I also studied about multi-microphone which can use conveniently in the super play that needs many microphones. If this multi-microphone is prodused, we could expect better sound quality and a big progress in stereo recording technology.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.10-16
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• 2009

Purpose: As the number of patients has increased since the installation of a PET/CT, we are now examining about 2500-3000 annually. We have realized that if we properly adjust a pitch under the same condition of a CT during a PET/CT exam, radiation quantity that reaches the patient can change. In order to reduce the exposure dose of a patient, the research examines a method of reducing the exposure dose of a patient by controlling the pitch during a PET/CT exam, viewing whether the adjustment of the pitch influences CT image and PET SUV. Methods: The equipment used is a Biograph Positron Emission Tomography (PET) Scanner (CT type: TRCT-240-130 (WCT-240-130)) of Siemens company. For the evaluation of exposure dose of a patient, we measured radiation quantities using a PTW-DIADOS 11003/1383, which is a CT radiation measurement instrument used by Siemens. We measured and analyzed the space resolutions of CT images caused by the change of pitches using an AAPM Standard Phantom in order to see how the adjustment of pitches influenced the CT images. In addition, in order to obtain SUVs caused by each change of pitches using a PET source made with a solid radioactive cylinder phantom, we confirmed whether the SUVs changed in the PET/CT images by calculating the SUVs of the fusion images caused by the change of pitches after obtaining CT and PET images and finishing the test. Results: 2slice CT scanner showed that radiation quantities largely dropped when pitches ranged from 0.7 to 1.3 and that the reduction of radiation quantities were smaller when pitches ranged from 1.5 to 1.9. That is, we found that the bigger pitch values are the smaller the radiation quantities of a patient are. Moreover, we realized that there is no change of SUVs caused by the increase of pitches and that pitch values do not influence PET SUVs and the quality of CT images. It is judged that using 1.5 as a pitch value contributes to the reduction of exposure dose of a patient as long as there is no problem in the quality of an image. Conclusions: When seeing the result of the research, hospital using a PET/CT should make an effort to reduce the exposure dose of a patient seeking pitch values appropriate for their hospital within the range in which there is no image distortion and PET SUVs are not influenced from pitches. We think that the research can apply to all multi-detectors having a CT scanner and that such a research will be needed for other equipments in the future.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.1
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• pp.120-139
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• 1996

Experiment was performed to study the heat transfer characteristics in 27 kinds of 15 : 1 scale models of multi-louverred fin heat exchangers with a wide range of variables(R $e_{Lp}$ =100~1, 800, $L_p$/F$p$=0.3~0.9, $\theta$=20$^{\circ}$~40$^{\circ}$). Thermofoil heaters were used to heat the louver fins and the local average Nusselt number for each louver in the louver array was obtained at constant wall temperature conditions. Correlations are developed to predict the heat transfer characteristics and drag coefficients. Generally, the heat transfer characteristics in the multi-louvered fins is shown to be similar to those of the laminar heat transfer on a flat plate. As the Reynolds number, the louver pitch to fin pitch ratio$L_p$/F$p$and the louver angle($\theta$) increase respectively, the average Nusselt number increases, but the variation of average Nusselt number as a function of the louver angle is smaller than that as a function of the louver pitch to fin pitch ratio. In case of$L_p$/F$p$ <0.5, the average Nusselt number of the 3rd louver is especially lower than the others, it is expected that it is due to the flow structure such as a recirculation flow and a flow separation.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.221-225
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• 2000

The effect of twisting on the microstructural evolution and critical current of BSCCO superconductor tape has been evaluated. Twisting pitches of the tapes are in the range of 8-70 mm and uniformly deformed. The critical current of twisted tape was dependent on the twist pitch. Specifically, it was observed that the critical current decreased with decreasing twist pitch, and only 50% of critical current was retained when the tape was twisted to a pitch of 8 mm. This reduction of the critical current may be related to the interface irregularity, smaller grain size, worse texture and the presence of cracks due to the induced strain during the twisting processing.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.147-150
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• 2002

This paper describes procedures to implement a real-time pitch analyzer using Matlab. Matlab is a multi-purpose signal-processing tool. Using this tool real-time analysis tool is implemented. To make it real-time we used data acquisition toolbox which comes with Matlab. Autocorrelation method was used as a basic algorithm. The resulting pitch informations are displayed in two different forms, i.e. instantaneous pitch plot and pitch track. V/UV decision is performed using zero crossing rate and energy Informations based on 500 utterances.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.65-66
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• 2008

• The Journal of Korea Robotics Society
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• v.12 no.1
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• pp.11-18
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• 2017

Static balance of an articulated robot arm at various configurations requires a torque compensating for the gravitational torque of each joint due to the robot mass. Such compensation torque can be provided by a spring-based counterbalance mechanism. However, simple installation of a counterbalance mechanism at each pitch joint does not work because the gravitational torque at each joint is dependent on other joints. In this paper, a 6 DOF industrial robot arm based on the parallelogram for multi-DOF counterbalancing is proposed to cope with this problem. Two passive counterbalance mechanisms are applied to pitch joints, which reduces the required torque at each joint by compensating the gravitational torque. The performance of this mechanism is evaluated experimentally.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.2
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• pp.140-154
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• 1994

Experimental studies were performed to determine the characteristics of flow structure and pressure drop in 15 : 1 scale models of multi-louvered fin heat exchanger in a wide range of variables($L_P/F_P=0.5{\sim}1.23$, ${\theta}=27^{\circ}{\sim}37^{\circ}$, $Re_{LP}=50{\sim}2000$). Flow structure inside the louvered fin was analyzed by smoketube method and new correlations on flow efficiency and drag coefficient were suggested. The new definition for flow efficiency, which modifies the existing flow efficiency, can predict the flow efficiency in the range above mentioned and is represented as a function of Reynolds number, louver pitch to fin pitch ratio, louver angle at low Reynolds number. Drag coefficient which is defined here is a function of Reynolds number, louver pitch to fin pitch ratio, louver angle below critical Reynolds number, and can be represented by a function of louver pitch to fin pitch ratio only above the critical Reynolds number.