• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.28-35
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• 2013

Micro electrical discharge machining (EDM) as a non-contact machining process is very effective for micromachining with a thin electrode because of its low machining reaction force. The micro-electrode machining device has the advantage of maintaining high precision through the whole processes and uses a feeding wire in the thin electrode tool manufacturing process. This study describes the design and evaluation of a micro-electrode machining device using optical photo-interrupter. The electrode was fabricated by reverse electrical discharge machining. The performance of designed system was evaluated to measure tension force according to feed speed of wire. This system for micro electrode fabrication proves the feasibility in the micro-EDM process of the micro holes and parts for industrial applications.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.195-198
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• 1994

A bubble counter was designed and fabricated for the measurement of gas production rate on the basis of number of bubbles produced from yeast fermentor. The sensor was consisted of bubble forming device and electronic signal processing circuitry. The bubble forming device was built with bubble collector and liquid cell to form uniform size of bubble. Bubbles were counted by pulses formed by photo-interrupter circuitry having 8-bit binary latch counter. The gas production rate curves on the basis of bubble counted showed a good agreement to that of growth curves obtained by the optical measurement method. The sensor was succesfully applied to monitoring of the nutrient utilization test with glucose and galactose media.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.6-8
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• 1994

Switched reluctance motor drive system is well known as a variable speed drive system because it has a simple motor structure and a simple driving circuit. Widely slotted photo interrupter has been investigated as a position sensor for SRM speed control because it has advantages of low cost and simple structure. However it has low resolution and it produces dead-time signal. This paper studies variable speed SRM drive system with slotted photo-interrupter. Controller in this study is constructed by using fuzzy controller that covers system nonlinearities and small perturbations in sufficiency. The performance of this system is evaluated through computer simulation and experiment results.

• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.391-394
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• 1993

For the automation of Tackjoo fermentation, a sensor measurable gas production during brewing and a controller were built. The performance tests were carried out at 10 litter Tackjoo fermentor, The sensor was consisted of a transparent acryl cell for bubble formation and photo-interrupter for the detection of bubbles of 0.018ml size. The fermentation controller was fabricated with a single chip microcomputer (MC68705R3) and provided with both the monitoring module of temperature measurement and the valve controling device for the cooling water circulation in coil type heat exchanger. The operation programs were developed and systemized in ROM. With this computer system, the gas production amount and rate were acquired during the Tackjoo fermentation. The fermentation curve based on the gas production rate showed a good agreement with that of alcohol concentration. The maximum rate of gas production was found after 24 hr at $30^{\circ}C$. The correlation equation between the gas production and alcohol concentration was established and used as the control algorithm of the fermentation.