• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.4
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• pp.346-352
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• 1982

The vibration characteristics of hyoid gears are experimentally investigated with backlash and tooth mesh frequency varied. Experiments are performed with two types of gear sets; well-machined and over-lapped gears. Through the experimental works, a constant torque 0.8kg.m is applied to th gears and a pulse type of trigger signal synchronizing tooth contact is used to measure the tooth mesh frequency and to average the gear vibration signal in the time domain. The time averaged vibration signals are frequency analyzed by a digital signal analyzer. The experimental results show the vibration characteristics of the two different types of gears in relation to backlash amount and mesh frequency variations are well differentiated by harmonic amplitudes and their ratios, and peak-to-peak amplitude of the gear vibration.

• The Plant Pathology Journal
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• v.26 no.1
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• pp.1-7
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• 2010

Phosphorylation is a major post-translational modification of proteins that regulate diverse signal transduction pathways in eukaryotic cells. 14-3-3 proteins are regulatory proteins that bind to target proteins in a phosphorylation-dependent manner and have been shown to play an important role in plant growth and development, primary metabolism, and signal transduction. Because phosphorylation plays a critical role in signal transduction pathways to trigger plant immunity, involvement of 14-3-3 proteins in plant immunity has been suggested for a long time. Recent studies have provided new evidence to support a role for 14-3-3 proteins in plant immunity. This review will briefly discuss general characteristics of 14-3-3 proteins and their involvement in plant immunity.

• Journal of Power System Engineering
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• v.16 no.1
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• pp.72-77
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• 2012

Acoustic emission (AE) is known to be sensitive to fracture process and so it was expected that AE data may propose as a means of monitoring the fracture information. The aim of this study is to analyze the characteristic of AE signal emitted from glass during Vickers indentation. To observe AE characteristics by surface effect, both glass and coating glass were studied. During Vickers indentation loading, AE signal resulted from penny-like crack is detected. During Vickers indentation unloading, AE signal resulted from both radial/median crack and lateral crack is detected. In case of indentation on glass, the emission energy(${\epsilon}$) is found to be approximately proportional to the fourth power of the crack length. In case of indentation on coating glass, the emission energy(${\epsilon}$) is approximately proportional to the crack length.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1503-1511
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• 2013

This paper deals with the analysis of leakage current characteristics of silicone rubber insulator in order to develop a new condition monitoring tool to identify the flashover of outdoor insulators. In this work, laboratory based pollution performance tests are carried out on silicone rubber insulator under ac voltage at different pollution levels and relative humidity conditions with sodium chloride (NaCl) as a contaminant. Min-Norm spectral analysis is adopted to calculate the higher order harmonics and Signal Noise Ratio (SNR). Choi-Williams Distribution (CWD) function is employed to understand the time frequency characteristics of the leakage current signal. Reported results on silicone rubber insulators show that the flashover development process of outdoor polymer insulators could be identified from the higher order harmonics and signal noise ratio values of leakage current signals.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.75-81
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• 1997

Automatic monitoring the cutting state is one of the important problems to increase the reliability of modern machining processes. In this study, cutting force signals were used in order to monitor the tool wear and fracture in the turning process. Turning experiments were performed using cemented carbide insert tools(K20) and STS304 steel as a workpiece. Cutting force signal characteristics and histogram analysis method were used to recognize the cutting states. It was found that tool wear and fracture can be diagnosed from the cutting force signal coefficient of variation(C.V.) and histogram analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.905-908
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• 2007

The purpose of this work is to obtain fundamental data about fatigue crack detection of the welded exhaust flange by using the AE method. The acoustic emission method as a nondestructive evaluation is one of high technical test for realtime monitoring in the dangerous industry fields. Signal analysis of both AE sensor and accelerometer for fatigue crack failure are presented in this paper.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1347-1351
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• 1987

This thesis aims at studying laplacian pyramid vector quantization which keeps a simple compression algorithm and stability against various kinds of image data. To this end, images are devied into two groups according to their statistical characteristics. At 0.860 bits/pixel and 0.360 bits/pixel respectively, laplacian pyramid vector quantization is compared to the existing spatial domain vector quantization and transform coding under the same condition in both objective and subjective value. The laplacian pyramid vector quantization is much more stable against the statistical characteristics of images than the existing vector quantization and transform coding.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.390-394
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• 2003

It is very important to simulate various mobile communication channels for the reliable system design and performance tests. Therefore, a new method is proposed in this paper to improve the conventional one for the purpose of the efficient channel simulation having various characteristics. A newly proposed method can simulate any narrow band channel very efficiently from the given Doppler power spectrum model. Also, it has many simulation advantages considering the variety of wireless channel conditions since parameters related with channel characteristics, such as a signal power, signal to noise ratio, direct signal power ratio, etc., can be easily changed according to various propagation environments to be tested.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.3
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• pp.10-21
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• 1993

Bilinear models are attractive for adaptive filtering applications because they can approximate a large class of nonlinear systems adequately, and usually with considerable parsimony in the number of coefficients compared with Volterra models. But bilinear filters have stability problem because they involve nonlinear feedback. Adaptive algorithms for bilinear filters may be diverge and have poor convergence characteristics when input signal is large In this paper, necessary and sufficient condition for mean square stability of bilinear filters for given input signal statistics is briefly described, and the method obtaining the input bound to guarantee the stability of bilinear filters is presented. New RPEM algorithm, which does not diverge and has the superior convergence characteristics compared with the conventional RPEM algorithm when input signal is large, is derived by applying the time-varying Kalman filtering concept to the conventional RPEM algorithm.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.379-384
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• 2003

Noise is a problem in many electronic circuits and active control system. Arising from spuriously coupled noise from other circuits, it corrupts the signal of interest and introduces an uncertainty into information it contains. In this paper, re have researched noise characteristics of the inductive displacement sensor which has been designed. n first present basic concept and characteristics of magnetic field-coupled noise in the sensor output signal. Then, n are present relation noise and sensor performances. Finally, we concentrate low noise design of a sensor driver and a signal detection circuit.