• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.1
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• pp.7-14
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• 2006

In this paper, an in-process diagnosis method for performance of position control servo system was studied, which was based upon null bias, slew-rate ratio and delay time measurement. Slew-rate ratio and delay time were analyzed by theoretical analysis, computer simulation and experiment. As a result of these analysis, when spool of servovalve was weared, slew-rate ratio was decreased and delay time was increased.

• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.2
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• pp.1-7
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• 2004

In-process diagnosis is essential to achieve predictive maintenance in industrial plants. An in- process diagnosis method was proposed for hydraulic servo systems, which was based upon leakage flow measurement. Leakage due to servovalve wear was analysed and modeled mathematically far computer simulation work. The key idea of diagnosis algorithm is that when monitoring signals, such as servovalve input and load displacement are in steady states, the return-line flow of hydraulic servo systems can be regarded as null-leakage of servovalve. Virtual experiments were performed to ensure effectiveness of the proposed diagnosis method.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.2
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• pp.22-30
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• 2009

An in-process method of diagnosing the spool wear of hydraulic servovalves was explored. The diagnostic method discussed in this paper is for force-control hydraulic servo systems. The key principle used is that pressure sensitivity of a servovalve drops as the valve spool wears out so that it is possible to determine the spool condition by monitoring pressure sensitivity. A diagnostic algorithm was developed and evaluated through numerical simulation and experiments. Two major steps of diagnosis are the evaluation of null bias of the servovalve and the approximation of pressure sensitivity, both of which could be successfully done during normal operation of a servo system. The difference between a new servovalve and a worn valve could be clearly detected in-process, and the diagnostic test was found to be repeatable.

• Journal of Technology Innovation
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• v.28 no.4
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• pp.1-26
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• 2020

Due to the spread of Corona 19 around the world, Infectious Disease Medicine and New Medical Devices such as Diagnostic Agent are being rapidly developed and launched, and for the fast supply and demand of these, each country has eased import regulations or has implemented policies for fast approval(NIDS, 2020). On the other hand, New Developed Medical Devices that are not related to New Infectious Diseases, they are still entering the market through strict licensing and licensing regulations, such as delay and cancellation in the test inspection process, etc. Therefore, This Study specialized in the government-managed laws encountered when New Medical Devices enter the market, derive Factors influencing the Strength of Regulations, analyzes the Strength of Regulations, and proposes a Regulatory Response Framework. The Research Method was conducted by Literature Research, was applied by Failure Mode and Effects Analysis(FMEA) Method, Expert Interview(1st): Idea Collection, Expert Interview(2nd): Validation, and Priority through the Application Process of FMEA Method. A Method of Quantifying the Intensity of Regulation was proposed by multiplying the Impact of the Influencing Factors for each stage of regulation and the Burden Impact for each type of Regulatory Affairs to find the Importance of the Regulatory Factors and multiplying the Severity of the Regulatory Impact. The Implications are that major overseas countries and the Korean government are actively responding with Special Regulatory Policies and Mitigation Policies for fast licensing of New Developed Medical Devices in accordance with Corona 19. It is expected that the direction for improvement of regulations and measures to respond to regulations will be implemented so that a more proactive and preemptive response to the regulatory process of the licensing policy for New Devices can be achieved.