• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3A
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• pp.272-280
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• 2009

Measurement of the background radio noise is very important process being used in survey of radio noise environment, calculating the threshold level for the frequency occupancy measurement and so forth. First step of background radio noise measurement is to select the sample sub-band which is mostly dominated by the background white Gaussian noise (WGN) within the target band. The second step is to carry out the main measurement of radio noise on this selected sample sub-band for the representative value of the noise power. In this paper, a method for selection of sample sub-band for the effective background radio noise measurement using SVD is proposed under the assumption that background radio noise is WGN. The performance of the proposed method is compared with that of the APD method which is widely used for the same purpose. Simulation results are shown to demonstrate the high performance of the proposed method in comparison with the existing APD method.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.2
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• pp.165-171
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• 2004

Owing to small sizes and high density to the semiconductor It, it is difficult to discriminate the defects of ICs by human eyes. High precision inspection system with computer vision is essentially established for the manufacturing process due to the variety of defective parts. Especially it is difficult to implement the algorithm for the coplanarity of IC leads. Therefore in this paper, the inspection system which can detect the defects of the SOP types of ICs having 1cm${\times}$0.5cm of the chip size is implemented and evaluated it's performance. In order to optimally detect various items, some principles of geometry are theoretically presented , length measurement, pitch measurement, angle measurement, brightness of image and correcton of position. The interface circuit is designed for implementation of inspection system and connected the HANDLER. In the result, the system could detect two ICs' defects per second and confirmed the resolution of 20$\mu$m per pixel.

• Journal of ILASS-Korea
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• v.27 no.2
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• pp.84-93
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• 2022

To implement carbon-neutrality in transportation sectors until 2050, hydrogen is considered a promising fuel for internal combustion engines because hydrogen does not contain carbon itself. Although hydrogen does not emit CO₂ emission from its combustion process, the low energy density in a volume unit hinders the adoption of hydrogen. Therefore, the understanding of hydrogen jet behavior and measurement of equivalence ratio must be conducted to completely implement the high-pressure hydrogen direct injection. The main objective of this research is feasibility test of hydrogen local equivalence ratio measurement by laser-induced breakdown spectroscopy (LIBs). To visualize the macroscopic structure of hydrogen jet, high-speed schlieren imaging was conducted. Moreover, LIBs has been adopted to validate the feasibility of hydrogen local equivalence ratio measurement. The hydrogen injection pressure was varied from 4 MPa to 8 MPa and injected in a constant volume chamber where the ambient pressure was 0.5 MPa. The increased injection pressure extends the vertical penetration of hydrogen jet. Due to the higher momentum supply when the injection pressure is high, the hydrogen has easily diffused in all directions. As the laser trigger timing has delayed, the low hydrogen atomic emission was detected due to the longer mixture formation time. Based on equivalence ratio measurement results, LIBs could be applied as a methodology for hydrogen local equivalence ratio measurement.

• The Journal of the Acoustical Society of Korea
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• v.43 no.3
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• pp.344-350
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• 2024

A Reference Sound Source (RSS) is an important standard device employed in measuring sound power. The specifications of RSS is specified in international standards, and it is classified as a major calibration item in the field of acoustic metrology. Since the output power of RSS is affected by the supply voltage, each country needs to secure its own calibration service system. In this study, a procedure for calibrating a RSS is established based on the reverberant room conditions and uncertainty evaluation is conducted. Basically, the calibration procedure can apply a precision measurement process of acoustic power, and here, the measurement method using the reverberation chamber of ISO 3741 is applied. For this purpose, a measurement system is constructed, measurements are conducted with two types of RSS, and measurement uncertainty is evaluated. Through measurement examples, it is confirmed that the non-uniformity of the sound pressure distribution in the reverberation room and the volume measurement uncertainty contributed significantly to the overall uncertainty. Additionally, the influence of input voltage is experimentally examined to examine the uncertainty contribution that can be reflected in acoustic power measurements.

• Journal of the Korean Professional Engineers Association
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• v.33 no.5
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• pp.45-48
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• 2000

DyeMax-L system(a real-time dyeing measuring system) which can do on line monitoring of dyeing process and measurement of the exhaustion of individual dye in mixtured dyes were developed By using the instrument, the compatability of mixture dyes and changes of exhaustion behavior of each dye with the variation of dyeing auxiliaries and dyeing conditions to get factors for control of dyeing

• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.31-36
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• 2002

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.195.2-195
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• 2000

• The Microorganisms and Industry
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• v.11 no.1
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• pp.21-33
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• 1985

이글은 다음과 같이 구성되어져 있다. preface 1) introduction 2) general information 3) folin protein determination 4) cellobiase assay 5) filter paper assay for saccharifying cellulase 6) carboxymethyl cellulase assay for endo-.betha.-1,4-glucanase 7) additional assay procedure for endoglucanase 8) evalutaiton of cellulase under process conditions 9) general remartks, references.

• The Journal of Engineering Geology
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• v.5 no.2
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• pp.233-235
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• 1995

Orientation of the linear structure looking simply uniaxial has to be understood to be of cubic property in connection with other fabric elements. It is necessary for not only the measurement and the correction, but also for the analysis process.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.451-452
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• 2005