• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1100-1109
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• 2006

In this study, two different technologies which can measure temperature simultaneously at many points are introduced. One is to use a thermal sensor cable that is comprised of addressable thermal sensors connected in parallel within a single cable. The other is to use an optic fiber with Distributed Temperature Sensing (DTS) system. The difference between two technologies can be summarized as follows. A thermal sensor cable has a concept of 'point sensing' that can measure temperature at accurate position of a thermal sensor. So the accuracy and resolution of temperature measurement are up to the ability of the thermal sensor. Whereas optic fiber sensor has a concept of 'distributed sensing' because temperature is measured by ratio of Stokes and anti-Stokes component intensities of Raman backscatter that is generated when laser pulse travels along an optic fiber. It's resolution is determined by measuring distance, measuring time and spatial resolution. The purpose of this study is that application targets of two temperature measurement techniques are checked in technical and economical phases by examining the strength and weakness of them. Considering the functions and characteristics of two techniques, the thermal sensor cable will be suitable to apply to the assessment of groundwater flow, geothermal distribution and grouting efficiency within 300m distance. It is expected that the optic fiber sensor can be widely utilized at various fields (for example: pipe line inspection, tunnel fire detection, power line monitoring etc.) which need an information of temperature distribution over relatively long distance.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.5
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• pp.113-120
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• 1994

Silicon flow sensor that can detect the velocity and direction of air flow was designed and fabricated by integrated circuit process and bulk micromachining technique. The flow sensor consists of three-layered dielectric diaphragm, a heater at the center of the diaphragm, and four thermopiles surrounding the heater at each side of diaphragm as sensing elements. This diaphragm structure contributes to improve the sensitivity of the sensor due to excellent thermal isolation property of dielectric materials and their tiny thickness. The flow sensor has good axial symmetry to sense 2-D air flow with the optimized sensing position in the proposed structure. The sensor is fabricated using CMOS compatible process followed by the anisotropic etching of silicon in KOH and EDP solutions to form I$\mu$ m thick dielectric diaphragm as the last step. TCR(Temperature Coefficient of Resistance) of the heater of the fabricated sensors was measured to calculate the operating temperature of the heater and the output voltage of the sensor with respect to flow velocity was also measured. The TCR of the polysilicon heater resistor is 697ppm/K, and the operating temperature of the heater is 331$^{\circ}C$ when the applied voltage is 5V. Measured sensitivity of the sensor is 18.7mV/(m/s)$^{1/2}$ for the flow velocity of smaller than 10m/s.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.7
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• pp.418-423
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• 2000

The fiber Fabry-Perot interferometric(FFPI) sensor is well known in the field of industrial diagnosis due to its outstanding properties such as tiny size, simple and rugged structure, and easy interrogation. As other fiber interferometric sensors, it also suffers from ambiguous output caused by highly periodic feature in its optical transfer function. In most cases, the ambiguity leads to relatively short dynamic operating range and long processing time during power-on reset, which limits its application to some specific fields requiring very high resolution. In this paper a method based on double sensing scheme was proposed to overcome the above difficulty. By employing a fringe selection auxiliary FFPI sensor the original FFPI sensor can identify its true position on the phase domain. The performance test with 10mm FFPI sensor and a thermocouple temperature sensor for reference shows wide dynamic range 0-900$\ell$ keeping a reasonable resolution of 0.1$\ell$ over the entire range.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.38-41
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• 2001

Switched reluctance generators(SRGs) attract much attention in the generator because of high efficiency, simplicity, and ruggedness. They require rotor position information In determine the turn-on and turn-off angle, but the rotor position sensor is less tolerant of extreme environmental conditions, such as high temperature or dust, so the position sensor is limited and undesirable. This paper describes a new approach to estimate the rotor position from the measured terminal voltages and currents of the SRG. The proposed method is based on the instantaneous inductance of the SRG. The proposed method is verified by computer simulations and experiments.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.3
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• pp.123-127
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• 2006

In a heating control system, the indoor temperature controller transfers temperature signals inputted from the temperature sensor and the user to the valve controller. The valve controller receives these signals then the valve controller controls the valve driving motor on two position control and controls the indoor temperature. When setting up a new valve driving motor from a long distance it is necessary to set up a new valve controller. But occasionary, due to construction, It is impossible to wire between the existing valve controller and the new valve controller. In this situation, the new and existing valve controllers can communicate via power line communication. In this paper it is proposed heating control system controls on two position control via power line communication.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1150-1155
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• 2006

In a heating control system, the indoor temperature controller transfers temperature signals inputed from the temperature sensor and the user to the valve controller. The valve controller recieves these signals then the valve controller controls the valve driving motor on two position control and controls the indoor temperature. When setting up a new valve driving motor from a long distance it is necessary to set up a new valve controller. But occasionary, due to construction, it is impossible to wire between the existing valve controller and the new valve controller. In this situation, the new and existing valve controllers can communicate via power line communication. In this paper it is proposed heating control system controls on two position control via power line communication.

• Journal of the Korean Magnetics Society
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• v.21 no.1
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• pp.32-36
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• 2011

We fabricated a sensor for measuring the water level and water temperature using GMR-SV (giant magnetoresistance-spin valve) device, simultaneously. It could be applied to the medical cooling system of the potassium titanylphosphate KTP) laser system for the therapy of a benign prostatic hyperplasia. The middle point of GMR-SV device was set to the near position of a high magnetic sensitivity with 2.8%/Oe. The sensitivity for the water level and water temperature of the fabricated sensor were $400\;m{\Omega}/mm$ and $100\;m{\Omega}/^{\circ}C$, respectively.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.10
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• pp.707-713
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• 2015

This paper proposes experimental results for control performance deterioration of a piezoelectric actuator under high temperature conditions due to external heat environment. In this work, a heat environment from 30 ℃ to 190 ℃ is established by a heat chamber which is capable of high temperature of heat environment. Inside the heat chamber, an experimental apparatus consisting of the stack type of piezoelectric actuator, laser sensor, gap sensor and temperature sensor is established. After evaluating temperature dependent blocking force, displacement and time response of a piezoelectric actuator inside the heat chamber, tracking control performances are evaluated under various temperature conditions via proportional-integral-derivative(PID) feedback controller. The desired position trajectory has a sinusoidal wave form with a fixed frequency. Control performances are experimentally evaluated at both room temperature and high temperature and presented in time domain.

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.281-285
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• 2009

Mobile robot has various sensors for describing the external world. The ultrasonic sensor widely applied to the most mobile robot to detect the obstacle and environment owing to low cost, its easy to use. However, ultrasonic sensor has major problems: the uncertainty information of sensor, false readings caused by specular reflection, multi path effect, low angular resolution and sensitivity to changes in temperature and humidity. This paper describes a sensor system for map building of mobile robot. It was made of low cost PSD (Position Sensitive Detector) sensor array and high speed RISC MPU. PSD sensor is cost effective and light weighting but its output signal has many noises. We propose heuristic S/W filter to effectively remove these noises. The developed map building sensor system was equipped on a mobile robot and was compared with ultrasonic sensor through field test.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.215-219
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• 1996

We developed a part of hydraulic stroke sensing cylinder for te purpose of position controlbyusing magnetic sensor and evaluated variously its performance its performance. In this paper, for the evaluation of the developed cylinder under various temperature change, thermal control systems are designed and controlled. It is composed of an heater case, temperature sensor, and interface circuits which included SCR(silicon controlled rectifier) for the control of the voltage's phase. To obtain various temperature conditions, the thermal systems are controlled by using Ziegler-Nichols PED tuning method. The thermalcontrol systems are used to experiment to evaluate whether the developed cylinder can obtain a stable output signal for detecting a stroke of the cylinder under the controlled temperature condition.