• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.1
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• pp.87-92
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• 2004

This review focuses on the developed and the being developed environmental sensors in particular biological sensors. As well as discussing the classification and some main principles, presenting current trend of the environmental sensors is given. Two main categories are immunosensors and catalytic sensors. In addition to those. DNA or RNA sensors or protein based sensors are discussed. Some crucial examples of the applications of such sensors are given to show how the sensor technology it used for environmental and biological monitoring, biomarkers of exposure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.8
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• pp.688-693
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• 2000

In this paper an optical voltage sensor and an optical current sensor which can be used for the measurement of impulse voltage and current are implemented. BSO single crystal is utilized as a voltage sensor(Pockels effect cell). An rare earth doped YIG is used as a current sensor(Faraday effect cell). A new signal processing technique is adopted not only to avoid the influences o external optical fiber pertubations of transmitting optical fiber but also to improves the frequency response characteristics of the fiber-optic voltage and current sensors. Experimental results show that optical voltage sensor has maximum 2.5% error within the voltage range from 0V to 500V. and optical current sensor has maximum 2.5% error within the current range and that of optical current sensor is about 1.5% within temperature range from -2$0^{\circ}C$ to 6$0^{\circ}C$. The proposed optical sensors have good frequency response characteristics within the frequency range from DC to 10MHz.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.307-310
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• 1999

This paper proposes a novel current control method of three-phase PWM rectifiers without phase current sensors. The features of this method are to reconstruct phase currents by using switching pattern of space vector modulation and to estimate phase currents by a predictive state observer for practical applications. Simulation results show that the performance of the proposed system is nearly the same as that of sensor-based system.

• Journal of IKEEE
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• v.21 no.4
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• pp.375-380
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• 2017

A differential current-to-time interval converter is presented for current mode sensors. It consists of a ramp voltage generator, a current mode sensor, a reference current source, two current-tunable Schmitt triggers, a one-shot multivibrator, and two logic gates. The design principle is to apply a ramp voltage to each input of the two current-tunable Schmitt triggers whose threshold voltages are proportional to the drain current values of the current mode sensors. A proposed circuit converts a current change in the ISFET biosensor into its equivalent pulse width change. A prototype circuit built using TSMC 0.18 nm CMOS process exhibit a conversion sensitivity amounting to $726.9{\mu}s/pH$ over pH variation range of 2-12 and a linearity error less than ${\pm}0.05%$.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.836-839
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• 1997

In recent years, much progress has been made in the automation of welding coped with a variety of highly flexible sensors. Among these sensors, only the eddy current sensor can detect the center location of the butt joint whose gap distance is zero. Thus, in this study the eddy current sensor is used to develop a robust and useful joint tracking system. The developed system is tested to qualify the performance of the system and seam tracking algorithm is proposed and two simulation are executed to show the performance of the proposed tracking algorithm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.809-816
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• 2008

With increasing demands for reducing cost of maintenance which can detect machine fault automatically; low cost and intelligent functionality sensors are required. Rapid developments, in semiconductor, computing, and communication have led to a new generation of sensor called "smart" sensors with functionality and intelligence. The purpose of this research is comparison of machine fault classification between general analyzer signals and smart sensor signals. Three types of sensors are used in induction motors faults diagnosis, which are vibration, current and flux. Classification results are satisfied.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.283-292
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• 2020

Current sensors that use a Hall element and Hall IC to measure the magnetic fields generated in steel silicon core gaps do not distinguish between direct and alternating currents. Thus, they are primarily used to measure direct current (DC) in industrial equipment. Although such sensors can measure the DC when installed in expensive equipment, ascertaining problems becomes difficult if the equipment is set up in an unexposed space. The control box is only opened during scheduled maintenance or when anomalies occur. Therefore, in this paper, a method is proposed for facilitating the safety management and maintenance of equipment when necessary, instead of waiting for anomalies or scheduled maintenance. A Bluetooth 4.0 low-energy current-sensor system based on near-field communication is used, which compensates for the nonlinearity of the current-sensor output signal using a piecewise linear model. The sensor is controlled using its generic attribute profile. Sensor nodes and cell phones used to check the signals obtained from the sensor at 50-A input currents showed an accuracy of ±1%, exhibiting linearity in all communications within the range of 0 to 50 A, with a stable output voltage for each communication segment.

• Journal of Ocean Engineering and Technology
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• v.29 no.2
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• pp.199-206
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• 2015

Regular high-strength carbon steel is currently the most commonly used pipe material for onshore and offshore pipelines. The corrosion of offshore pipelines is a major problem as they age. The collapse of these structures as a result of corrosion may have a heavy cost is lives and assets. Therefore, their monitoring and screening is a high priority for maintenance, which may ensure the integrity and safety of a structure. Monitoring risers and subsea pipelines effectively can be accomplished using eddy current inspection to detect the average remaining wall thickness of corroded low-alloy carbon steel pipelines through corrosion scaling, paint, coating, and concrete. A test specimen for simulating the offshore pipeline is prepared as a standard specimen for an analysis and experiment with differential bobbin eddy current sensors. Using encircling coils, the signals for the defect in the simulated specimen are analyzed and evaluated in experiments. Differential bobbin eddy current sensors can diagnose the defects in a specimen, and experiments have been carried out using the developed bobbin eddy current sensor. As a result, the most optimum coil parameters were selected for designing differential bobbin eddy current sensors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.394-399
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• 2012

In recent years, MEMS sensors show huge attraction in machine condition monitoring, which have advantages in power, size, cost, mobility and flexibility. They can integrate with smart sensors and MEMS sensors are batch product. So the prices are cheap. And the suitability of it for condition monitoring is researched by experimental study. This paper presents a comparative study and performance test of classification of MEMS sensors in target machine fault classification by 3 intelligent classifiers. We attempt to signal validation of MEMS sensor accuracy and reliability and performance comparisons of classifiers are conducted. MEMS accelerometer and MEMS current sensors are employed for experiment test. In addition, a simple feature extraction and cross validation methods were applied to make sure MEMS sensors availabilities. The result of application is good for using fault classification.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.363-364
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• 2016

In this paper, a novel bridgeless interleaved power factor correction circuit with single current sensor is proposed. The proposed control strategy requires only one current sensor for the interleaved bridgeless PFC. By sampling the output current, all the boost indictor currents can be calculated and used to control the input current according to the input voltage. The reduced number of current sensors and associated feedback circuits helps reduce the cost of system. The problem caused by the unequal current gain between current sensors inherently does not exist in the proposed topology. Thus, current sharing between converters can be achieved more accurately and the high frequency distortion is decreased. In addition, the proposed technique can be applied to the other kinds of interleaved PFC topologies. Performance of the proposed control strategy is verified by the experimental results with 6.6kW bridgeless interleaved PFC circuit.