• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.9
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• pp.59-64
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• 2011

Ultra wideband radars attract considerable attention as a short range automotive radar because of its high range resolution. Radar signal reflected from a target often contains unwanted echoes called as clutter, so the detection of target is difficult due to clutter echoes. Therefore, it is important to investigate the radar detector for better detecting from the reflected signals. In this paper, the optimal detector is obtained for various mean and variance value in log-normal clutter environment. The types of non-coherent detectors used are square law detector, linear detector, and logarithmic detector. The performances of detectors are compared in log normal clutter environment and the suitable detector is determined for automotive short range radar application.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.1020-1022
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• 2013

In this paper, proposed peak detector for the measurement of pulse radiation dose. The speed of the pulse radiation signal is the between a few ns and tens ns. Therefore, it is difficult to measure peak voltage. Peak Detector maintains the peak voltage generated from the sensor for a few ms and the converted signals can be easily measured using the ADC. The peak detector simulation results peak value remained of more than 1ms. Pulse radiation irradiation test results, a dose of $1.95{\times}10^6rad/s$ was measured.

• Nuclear Engineering and Technology
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• v.36 no.1
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• pp.47-52
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• 2004

Recently, a new sintered pellet-type LiF:Mg,Cu,Na,Si TL detector which has a high sensitivity and good reusability, named KLT-300(KAERI LiF:Mg,Cu,Na,Si TL detector), was developed by the variation of the dopants concentrations and the parameters of the preparation procedure at KAERI (Korea Atomic Energy Research Institute). In this study, the thermoluminescent characteristics of the newly developed TL detectors were investigated. The sensitivity of the TL detector was compared with that of the TLD-100 by light integration. The dose linearity of the detector was tested from $10^{-6}$ Gy up to 30 Gy. The dose response was very linear up to 10 Gy and a sublinear response was observed at higher doses. The energy response of the detector was studied for photon energies from 20 keV to 662 keV. The result shows that a maximum response of 1.004 at 53 keV and a minimum response of 0.825 at 20 keV were observed. The reproducibility study for the TL detector was also carried out. The coefficients of variation for each detector separately did not exceed 0.016, and for all the 10 detectors collectively was 0.0054. Lower limit of detection for the detector was investigated at 70 nGy by the Harshaw 4500 TLD Reader and the residual signal of the TL detector was found to be $0.57\%$.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.2
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• pp.120-125
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• 2014

Conventional handheld metal detectors use a single induction coil to detect the metallic parts of explosive objects, and the detector generates an acoustic signal from its magnetic response to a metallic object so that an operator can confirm the existence of mines. Though metal detectors have very useful detection mechanisms to find mines, it is easy to cause a high false alarm ratio due to the detection of non-explosive metallic items such as cans, nails and other pieces of metal, etc. Also, because of the physical characteristic of a metal detector it is hard to detect non-metallic objects such as mines made of wood or plastic. Furthermore, the operator must move it to the left and right slowly and repeatedly to attain enough sensor signals to confirm the existence of mines using only a monotonous acoustic signal. To resolve the disadvantages of handheld detectors, many new approaches have been attempted, such as an arrayed detector and a visualization algorithm based on metal/non-metal sensor. In this paper, we introduce a visualization algorithm with a metal/non-metal complex sensor, an arrayed metal/non-metal sensor and the their testing and evaluation.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.7
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• pp.28-38
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• 1997

Previously, we have proposed the M-BECM(Modified-Band Edge Component Maximization), which is a symbol synchronization algorithm based on spectral line method for all-digital high speed digital communications. However, Until now, the characteristics of the timing detector based on the spectral line method including M-BECM was not analyzed, particularly the effect of a timing offset at the optimal convergence pont. In this paper, we analyze the timing dtector's characteristics of the M-BECM and present optimal design value. First, the expression for the timing detector's mean value(often called its S-Curver) as a function of the normalized symbol timing offset is derived. Next, the P $D_{bias}$, the value for compensating the timing offset at an optimal convergence point, and the bandwidth of bandpass filter in the timing detector are calculated. It is also shown and analyzed that the P $D_{bias}$ is affected by varuous factors such as the excess bandwidth of input signal, frequency offsets, noise and particularly, the excess bandwidth of input signal is a major parameter to decide P $D_{bias}$. Finally, analytic resutls are compared to simulation results.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1649-1651
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• 2002

Ultra-wide bandwidth (UWB) detection method has been widely used as a front end detection scheme for the ultra-high frequency (UHF) partial discharge (PD) monitoring systems. A broad-band video detector module was developed and characterized for the UHF UWB PD detection systems. The useable bandwidth of the module is more than 2 GHz and it is optimized for 50-ohm systems. The detection sensitivity and dynamic range of the module were characterized by using a known ns-width RF pulses of GHz range. The dynamic range is more than 6-decades and the module can detect pulsed RF signals down to 1 nW. The detector module can eliminate expensive equipment such as high speed oscilloscopes and radio frequency (RF) spectrum analyzers. Therefore, it enables one to use slow speed data acquisition systems for the PD monitoring at the UHF range. The detector module was used to detect real PDs of about <3 pC. The module converts the UWB PD signals into a low-bandwidth video signal with a high signal-to-noise ratio.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1991.10a
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• pp.45-47
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• 1991

In this research, we verify the relations between the mechanical hardness of a strip and the output of Residual Magnetic Flux Detector, which is installed in the end side of #2 CAL. First, we install the strip speed detector and get a hardness signal and a speed signal 2 seconds, and then do signal processing and send an output to a printer every 30 seconds. The system that performs above functions is Magnetic Hardness Data Acquisition & Processing System. We got the relation between output current and hardness for the strip of T3 BP through on-line tests. Seconds, we made a hardness Measurement Simulator and observed the speed characteristics of residual magnetic flux, with using it.

• International Journal of Control, Automation, and Systems
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• v.1 no.2
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• pp.203-205
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• 2003

A false signal problem of the bleed air leak detection system in a widely used modem airplane is studied in this paper. It is considered to be a problem of stability of the controller unit. An equivalent circuit is extracted from the study. The circuit is considered to be an alternative bridge. A mathematical model is derived to describe the stability of the circuit. The conclusion is drawn that the sending of the false signal is relevant to not only the sensors, but also the detector. If a parameter in the detector is readjusted, then the problem may be avoided.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.912-913
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• 2008

In this paper, peak detector of generator output voltage and variable gain controller is introduced for the fast dynamic response. The general r.m.s. detecting signal of generator has inherent time delay from the actual signal. So the dynamic response of generator using conventional PID controller has some problem in sudden load change. In order to overcome this problem, the peak detector and signal selector with variable gain controller is used in this paper. The proposed control scheme is verified from experimental test of 200kW diesel engine-generator.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.61-63
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• 1987

In this paper, we develope a system which can perform signal processing for bar-code laser scanner. This system is composed of optical detector and preprocessor. The former detects the diffused light and converts it into TTL lebel output. The latter discriminator valid data from various raw data and transmits data to micro-processor. The preprocessor consists of edge transition detector, latch signal generator, module counter, register array, adder array, and buffer memory control circuit etc..