• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.600-605
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• 2011

This paper shows field test and evaluation results for a wireless vehicle detector with anisotropic magneto-resistive (AMR) sensors. The detector consists of two AMR sensors and mechanical and electronic apparatuses. The AMR sensor senses disturbance of the earth magnetic field caused by a vehicle moving over the sensor and then produces an output indicative of the moving vehicle. In this paper, vehicle speeds are calculated by using two AMR sensors fixed on a board, with constant distance. To test and evaluate the accuracy of the detector in real traffic situations, the detector was installed on a local highway and vehicle speeds and volumes were measured both in a free running and a highly congested traffic. The measurements from the detector are compared with the reference measurements obtained from a traffic camera with the Mean Absolute Percentage Errors (MAPE), which has proved the usefulness of the detector in the field.

• Bulletin of the Korean Chemical Society
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• v.14 no.2
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• pp.211-215
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• 1993

A multichannel optical detector system employing a self-scanning linear photodiode array has been developed. The photodiode array detector system is designed for various applications which require fast, multichannel detection of transient signals. The detector system consists of a controller which runs on an IBM personal computer and a detector head connected to the controller through a DB-15 cable. The entire scanning of 1024 detector elements is achieved in 20 ms. By using an on-board 16-bit counter/timer, the operational mode of the photodiode array detector is fully programmable by software. The design considerations and the performance of the photodiode array detector system is presented.

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.130-131
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• 2009

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• Journal of Astronomy and Space Sciences
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• v.31 no.2
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• pp.177-186
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• 2014

The Immersion Grating Infrared Spectrometer (IGRINS) is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG Focal Plane Array (H2RG FPA) detectors. We present the design and fabrication of the detector mount for the H2RG detector. The detector mount consists of a detector housing, an ASIC housing, a Field Flattener Lens (FFL) mount, and a support base frame. The detector and the ASIC housing should be kept at 65 K and the support base frame at 130 K. Therefore they are thermally isolated by the support made of GFRP material. The detector mount is designed so that it has features of fine adjusting the position of the detector surface in the optical axis and of fine adjusting yaw and pitch angles in order to utilize as an optical system alignment compensator. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the structural and thermal analysis, the designed detector mount meets an optical stability tolerance and system thermal requirements. Actual detector mount fabricated based on the design has been installed into the IGRINS cryostat and successfully passed a vacuum test and a cold test.

• Journal of Satellite, Information and Communications
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• v.1 no.1
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• pp.59-64
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• 2006

The broadband power detector for power amplitude envelope detection of the direct-conversion Six-port output signal was designed and implemented in this paper. The power detector should be linearly operated to produce the linear amplitude and phase signal for input RF signals in required broadband frequency range. The power detector should be designed under conditions of matching circuit with low VSWR, which protect unbalanced phase signal from reflection signal due to mismatch between the output port of a six-port and the input port of a power detector. The designed power detectors, which were implemented in L-band with 50 ohm matching and Ku-band with multiple LC matching circuits and isolator, respectively, were analyzed in viewpoints of the utilization as a power detector of direct conversion Six-port. The dynamic range of designed power detectors were also measured and rvaluated as a power detector of Six-port circuit.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.11
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• pp.727-730
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• 2015

In this paper, we fabricated organic compounds detector using the MWCNT/PMMA (multi-walled carbon nanotube / polymethylmethacrylate) composite film. We used polymer film as a matrix material for the device framework, and introduced CNTs for reacting with the organic compounds resulting in changing electrical conductivity. Spray coating method was used to form the MWCNT/PMMA composite film detector, and pattern formation of the detector was done by shadow mask during the spray coating process. We investigated changes of electrical conductivity of the detector before and after the organic compounds exposure. Electrical conductivity of the detector tended to decrease after the exposure with various organic compounds such as acetone, tetrahydrofuran (THF), toluene, and dimethylformamide (DMF). Finally we conclude that organic compounds detection by the MWCNT/PMMA composite film detector was possible, and expect the feasibility of commercial MWCNT/PMMA composite film detector for various organic compounds.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.36-38
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• 2004

The detector size effect due to the spatial response of defectors is one critical source of inaccuracy in clinical dosimetry and has been a subject of numerous studies. Conventionally, the detector response kernel contains all of the influence that the detector size has on the measured beam profile. Various analytic models for this kernel have been proposed and studied in theoretical and experimental works. Here, we use a method to determine detector response kernel simply by using Monte Carlo simulation and convolution theory. Based on this numerical method and DOSIMETER, an EGS4 Monte Carlo code, the detector response for a Farmer type ion chamber embedded in water phantom is obtained. There exists characteristic difference in the simulated chamber readings between one with carbon graphite wall and the other with Acrylic wail. Using the obtained response and the convolution theory, we are planning to derive the detector response kernel numerically and remove detector size effect from measurements for 6MV, 10${\times}$l0cm2 and 0.5${\times}$10 cm2 photon beam.

• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.182-189
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• 2010

This paper defines the quorum-based fault-tolerant mutual exclusion problem in a message-passing asynchronous system and determines a failure detector to solve the problem. This failure detector, which we call the modal failure detector star, and which we denote by $M^*$, is strictly weaker than the perfect failure detector P but strictly stronger than the eventually perfect failure detector ◇P. The paper shows that at any environment, the problem is solvable with $M^*$.