• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.11
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• pp.1186-1193
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• 2009

In this paper, we propose DDS(Direct Digital Synthesizer) as a new implementation method of chirp LO(Local Oscillator) for compressive receiver applied for RFID signal detection in UHF band. We designed a receiver whose input frequency range is 908.5~914 MHz, DDL(Dispersive Delay Line) bandwidth is 6 MHz, and dispersion delay time is $13\;{\mu}s$. Chirp LO based on DDS is designed to meet $26\;{\mu}s$ sweep time and 12 MHz bandwidth for complete compressive mechanism. The measured 3 dB pulse width of the compressed signal of the fabricated receiver is 260 ns and the frequency resolution for simultaneous input signals is below 200 kHz. These performances indicate that the proposed chirp LO based on DDS and the compressive receiver is suitable for RFID signal detection in UHF band.

• Journal of Biosystems Engineering
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• v.27 no.6
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• pp.521-528
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• 2002

Rotary and plow implements are mainly utilized for the tillage operation in Korea, and a implement control system for agricultural tractors was designed and fabricated to improve the working accuracy and efficiency. The control system was composed of three units: 1) sensors fur detection of angle of liftarm, draft force, engine rpm, tillage depth and so on, 2) a controller, and 3) hydraulic circuits, which included solenoid valves and so on, for operation of three point linkage and implements. The control system can control the speed(high and low speed) of implements by adjusting input flow rates of the hydraulic cylinder which was controled by two speed valve, which was composed of a solenoid valve and a orifice. Indoor experiments were conducted to evaluate response characteristics of the designed implement control system under experimental conditions of various engine nm, two kinds of input flow rates of the cylinder and some input frequency. The results of experiments showed the response characteristics sufficient to use as the implement control system fur agricultural tractors.

• The Journal of the Acoustical Society of Korea
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• v.13 no.6
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• pp.24-30
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• 1994

In this paper, the system for detection of photoacoustic signal has been constructed by using CW $CO_{2}$ laser for an analysis of the photoacoustic signal In metals and aluminum carbon steel, brass have been used as sample. The photoacoustic signals of several nano amperes have been detected in each sample with varying modulation frequency of laser, time constant of lock-in amplifier, thickness of sample. The characteristics of photoacoustic signal has been analysed in term of phase angle by using signal processing technique. Results indicate that the photoacoustic signal can be stabilized by adjustment of time constant of lock-in amplifier, that the signal amplitude is proportional to the ratio of thermal expansion coefficient to thermal capacity of metal, and that the signal amplitude decreases exponentially with sample thickness as well as with modulation frequency.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.2
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• pp.75-82
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• 2000

This paper presents a method of detecting surface flaw of cold-rolled steel plate using image processing technique and a neural network classifier. The amount of steel plate surface image data is reduced by the wavelet transform. Features are extracted from the co-occurence matrix of the partial image corresponding to the low-frequency region, and a MLP neural network classifies into predetermined surface flaw categories. Simulations show the neural network classifier outperforms conventional vector quantization method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.187-189
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• 1995

A Surface Acoustic Wave Gas sensor for NO, CO, H$_2$gas detection was designed fabricated, and tested. A delay line device was designed to composite a single mode SAW oscillator which enables to measure a SAW velocity. To reduce the effect of temperature and humidity, dual delay line oscillator circuit was used. And final output was measured by digital frequency counter. NO, CO, H$_2$gas were detected by WO$_3$thin film deposited on the path of the Delay Line.

• Journal of electromagnetic engineering and science
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• v.10 no.1
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• pp.18-24
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• 2010

A Ka-band microstrip array antenna for wide-range detection of moving targets is analyzed through a photonicassisted reactive-near-field characterization technique. The antenna array employs a 3-dB-tapered feed network to suppress the sidelobe level while retaining a wide azimuth beamwidth for a wide detection range. The relative nearelectric field patterns of the array and its 3-dB-tapered feed lines have been measured using an electro-optic fieldmapping technique for minimally invasive millimeter-wave sensing. A number of typical limitations on the technique, involving bandwidth, low signal-modulation depth, and high laser-induced noise in high-frequency applications, have been overcome by suppressing the carrier portion of the optical interrogation beam.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.10
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• pp.909-916
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• 2016

The beacon receiver is an equipment which detects and measures the signal strength of transmitting satellite beacon signal. Beacon signals transmitted by satellites are low power continuous wave(CW) signals without any modulation intended for antenna steering to satellite direction and power control purposes on the earth. The beacon signal detection method using a very narrow band analog filter and RSSI(Received Signal Strength Intensity) has been typically used. However, it requires the implementation to track the frequency at the beacon receiver, thus a beacon frequency variation of the satellite due to temperature changes and long-term operation. Therefore, in this paper, the beacon signal detection receiver is designed by using a very narrow band digital filter array for a faster acquisition and SNR(Signal to Noise Ratio) method detection. For this purpose, by calculating the satellite link budget with the rain attenuation between satellite and ground station, and then extracting the received $C/N_o$ of the beacon signal, this work derives the bandwidth and the array number of the configured digital filter that gives the required C/N.

• Journal of IKEEE
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• v.22 no.3
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• pp.723-728
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• 2018

This paper proposes a signal detection method for IoT door lock system which is a new application field of VLC (Visible Light Communication). This paper describes the signal detection technique for user recognition that needs to be overcome in order to apply VLC to door lock system which has a demand for new technology due to security issue. This system has security and high signal detection characteristics because it uses existing infrastructure to communicate with visible light. In order to detect the signal using FFT, the signal of the user who accesses the authentication channel based on the pilot signal is detected, and the performance of the false alarm probability and detection probability is shown in the channel model.

• Journal of the Korea Society for Simulation
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• v.24 no.3
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• pp.45-54
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• 2015

This paper presents the influence of backlash can be greatly increased on the frequency response characteristic which is presented as the angular velocity of a motor to the motor input voltage, if the motor input voltage is adequately reduced. And, this paper verifies theoretically, analytically and experimentally the availability on the method of detecting the change of backlash magnitude by investigating on the change of the anti-resonance and resonance frequencies in the frequency response characteristic due to the change of backlash magnitude. The amount of change of anti-resonance frequency is more useful that of resonance frequency when detecting the change of backlash magnitude, because the change of anti-resonance frequency can be measured more stable. This paper also shows the sharp change of resonance frequency can be investigated when the motor input voltage is enough reduced. The work will be useful for the further research on the backlash estimation method of a servo system with a gear reducer.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3963-3967
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• 2013

Background: The presence of Epstein-Barr virus (EBV) in Non-Hodgkin's lymphoma can be identified by immunohistochemistry for detection of EBV latent membrane protein (LMP). The role of EBV as an etiologic agent in the development of non-Hodgkin lymphoma has been supported by detection of high levels of latent membrane protein 1 (LMP-1) expression in tumors. However, no study has been conducted in a Pakistani population up till now to determine the frequency of Epstein-Barr virus positivity. The objective of our study was to determine a value for non-Hodgkin lymphoma patients using EBV LMP-1 immunostaining in our institution. Materials and Methods: This study was carried out at the Department of Histopathology, Armed Forces Institute of Pathology (AFIP), Pakistan from December 2011 to December 2012. It was a cross sectional study. A total of 71 patients who were diagnosed with various subtypes of NHL after histological and EBV LMP-1 immunohistochemical evaluation were studied. Sampling technique was non-probability purposive. Statistical analysis was achieved using SPSS version 17.0. Mean and SD were calculated for quantitative variables like patient age. Frequencies and percentages were calculated for qualitative variables like subgroup of NHL, results outcome of IHC for EBV and gender distribution. Results: Mean age of the patients was $53.6{\pm}16$ years (Mean${\pm}$SD). A total of 50 (70.4%) were male and 21 (29.6%) were female. Some 9 (12.7%) out of 71 cases were positive for EBV-LMP-1 immunostaining, 2 (22.2%) follicular lymphoma cases, 1 (11.1%) case of T-cell lymphoblastic lymphoma, 4 (44.4%) cases of diffuse large B cell lymphomas, 1 (11.1%) mantle cell lymphoma and 1 (11.1%) angioimmunoblastic T cell lymphoma case. Conclusion: In our study, frequency of EBV in NHL is 12.7% and is mostly seen in diffuse large B cell lymphoma. This requires further evaluation to find out whether this positivity is due to co-infection or has a role in pathogenesis.