• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.372-376
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• 2004

Digital memory circuits have been developed very fast according to the progress of semiconductor technology But It was very difficult to memorize a high frequency radio signal. Many years ago an analog loop was used for store of radio frequency signal, and the digital radio frequency memory was made to the development of wideband amplifier and high speed sampler. We present a design of wide-band DRFM using Johnson code and the simulation results with respect to the sampling speed. in this paper.

• Journal of Sensor Science and Technology
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• v.3 no.2
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• pp.16-23
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• 1994

Developed fiber-optic biosensor for the detection of organophosphorus compounds in a contaminated water needs the analysis of an enzyme kinetics and the transport phenomena in the reaction part to analyze the sensor signal and to design the sensor. The enzyme inhibition kinetics was investigated and the reactor model was proposed to design the reaction part in the proposed sensor. Since the acetylcholinesterase was inhibited by the organophosphorus compounds, experiments for enzyme inhibition reaction were performed from 0 to 2 ppm to be detected by the developed sensor, and irreversible enzyme inhibition kinetics was proposed. The reactor parts were divided into the two phases, i.e. bulk phase and immobilized enzyme layer, to analyze the flow and diffusion. Sensor signal was able to be analyzed based on the total reactor model established by linking the enzyme reaction kinetics. Based on the proposed model, the effects of loading enzyme amount and enzyme layer thickness on the magnitude of readout signal were simulated.

• Tunnel and Underground Space
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• v.33 no.5
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• pp.425-434
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• 2023

To measure the wear amount of the TBM disk cutter in real time, it is important not only to automate the measurement using sensors, but also to stably transmit the measured data to the information processing system. In this study, we investigated the viability of utilizing Bluetooth Low Energy (BLE) technology to wirelessly transmit sensor data from the TBM cutter head to a receiver located at the chamber's rear. Through laboratory experiments, we analyzed the Received Signal Strength Index (RSSI) of the receiver considering various signal strength of the transmitter, separation distances between the transmitter and receiver and chamber fill materials. Our results demonstrate that wireless data transmission is feasible across all tested conditions when the transmitter signal strength is 0 dBm or higher.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.174-175
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• 2013

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.500-501
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• 2012

• The Journal of the Acoustical Society of Korea
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• v.36 no.4
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• pp.229-237
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• 2017

In this paper we propose an auto tonal detection method which exploits short term stationary when targets located in a detection beam area and then additional methods are proposed in order to reduce the computational complexity of the proposed method. The proposed method is adaptive to input signals and robust against interference caused by multiple targets because it compares an expected value of input signals with a threshold value which are estimated from a single beam while signals are keep stationary. The performances of the proposed methods are evaluated using by simulated data and acquired data from real ocean. The proposed method has shown better performance than conventional CFAR (Constant False Alarm Rate) methods.

• Journal of the Korean Society of Radiology
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• v.4 no.3
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• pp.5-11
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• 2010

In this paper, we are suggested development of dual-mode detector for dual-energy digital radiography. Design of dual-energy radiography module for commercial BIS (Baggage Inspection System) is used in the spectrum of the X-ray generator and detector for dual-mode features and radiological characteristics were analyzed. BIS suggestl on the image detector module being used to target X-ray tube to simulate X-ray spectrum and simulated spectrum to offer through the new radiographic characteristics of the detector modules were investigated. Using X-ray experiments with an increase in the thickness of the copper filter low energy detector (LED) and high-energy detector (HED) as the difference between the output signal increases. HED, especially in the size of the output signal decreases with increasing thickness of the copper filter was found.

• Journal of the Korean Geotechnical Society
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• v.34 no.4
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• pp.27-35
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• 2018

The objective of this study is to demonstrate the suitability of electromagnetic waves for evaluating necking defects in bored piles using electromagnetic waves. Experiments are conducted with small-scaled defective model pile with diameter of 150 mm and length of 270 mm. Two necking defects are generated at the upper and lower positions on two different sides of the model pile, respectively. The other two necking defects are generated at the upper and lower positions on the same side of the model pile. Electrical wires are installed alongside the stainless steel wire of a steel cage to configure a two-conductor transmission line. A time-domain reflectometer is used to generate and defect electromagnetic waves. The experimental results show that electromagnetic waves are reflected at the necking defects and the end of the model pile. In addition, calculated defect locations are almost the same as actual defect locations. This study demonstrates that electromagnetic waves can be effective tool for evaluating necking defects in bored piles.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.4
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• pp.57-62
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• 2014

Recently, research activities to develop services for providing safety information to the drivers in fast moving vehicles based on various wireless network technologies such as DSRC (Dedicated Short Range Communication), IEEE 802.11p WAVE (Wireless Access for Vehicular Environment) are widely being carried out. This paper presents a proof-of-concept model based on a robot-car for Dilemma Zone Decision Assistant Service using the wireless LAN technology. The proposed model system consists of a robot-car based on an embedded Linux OS equipped with a WiFi interface and an on-board unit emulator, an Android-based remote controller to model a human driver interface, a laptop computer to run a model traffic signal controller and signal lights, and a WiFi access point to model a road-side unit.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.1
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• pp.1-6
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• 2024

Spiders detect even tiny vibrations through their vibrational sensory organs. Leveraging their exceptional vibration sensing abilities, they can detect vibrations caused by prey or predators to plan attacks or perceive threats, utilizing them for survival. This paper introduces a nanoscale crack-based sensor mimicking the spider's sensory organ. Inspired by the slit sensory organ used by spiders to detect vibrations, the sensor with the cracks detects vibrations and pressure with high sensitivity. By controlling the depth of these cracks, they developed a sensor capable of detecting external mechanical signals with remarkable sensitivity. This sensor achieves a gauge factor of 16,000 at 2% strain with an applied tensile stress of 10 N. With high signal-to-noise ratio, it accurately recognizes desired vibrations, as confirmed through various evaluations of external force and biological signals (speech pattern, heart rate, etc.). This underscores the potential of utilizing biomimetic technology for the development of new sensors and their application across diverse industrial fields.