• Journal of Medicine and Life Science
• /
• v.21 no.1
• /
• pp.1-10
• /
• 2024

The purpose of this study is to determine the issues of supplementation and improvement to prepare for the outbreak of new infectious diseases such as new variants of coronavirus disease 2019 (COVID-19) to guide work for a strategic new response to infectious disease. Public officials of Jeju Special Self-governing Province and health personnel responding to COVID-19, working at six public health centers in Jeju-do region were administered a survey about additional preparations to be made in the future, based on the period when COVID-19 was treated legally as a first-class infectious disease. Frequency analysis was conducted on the collected data. The Likert 5-point scale and Kruskal-Wallis test were used to compare the scores for effective response to emerging infectious diseases according to demographics. Among the important factors identified for effective response to new infectious diseases, 'facilitation of cooperation with public institutions' and 'facilitation of cooperation with private institutions' had the highest scores. In the future, when a patient presents with a new infectious disease, the step that needs to be supplemented in each phase of the public health center's response is 'immediate response team operation'. Further, public health centers responded that 'expansion of dedicated personnel related to infectious diseases' needs to be improved to respond to new infectious diseases. Along with the results of this study, considering the difficulties experienced by health personnel responding to new infectious diseases in preparation for future outbreaks of new infectious diseases, and to respond effectively, detailed and clear guidelines for responding to quarantine of patients of new infectious diseases will be needed.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2528-2533
• /
• 2007

Thermoforming is one of the most versatile and economical processes available for the manufacturing polymer products. The drawback of thermoforming is difficult to get uniform thickness of final products. For the distribution of thickness strongly depends on the temperature distribution of sheet, the adjustment of heater power is very important In this paper, an optimization study for getting uniform temperature distribution was carried out using dual optimization steps. At first, the steady state optimal distribution of heater power is searched by numerical optimization to get uniform temperature of sheet surface. In the second step, time-dependent optimal heater inputs have been found out to decrease the temperature difference through the direction of thickness using Rseponse Surface Method and D-optimal method. The optimization results show that the time-dependent optimal heater power distribution gives acceptable uniform sheet temperature in the field of forming temperature..

• The Transactions of the Korean Institute of Power Electronics
• /
• v.18 no.4
• /
• pp.349-358
• /
• 2013

In this paper, the sensorless MPPT algorithm is proposed where the performance of varied duty ratio change has been improved using multi-layer neuro-fuzzy that aligns with neuro-fuzzy based optimized membership function. Since the change of duty ratio of sensorless MPPT is varied by using the neuro-fuzzy, the MPPT response speed is faster than the convectional method and is able to reduce the steady-state ripple. The neuro fuzzy controller has the response characteristics which is superior to the existing fuzzy controller, because of the usage of the optimal width of the fuzzy membership function. The effectiveness of the proposed method has been verified by simulations and experimental results.

• Transactions of The Korea Fluid Power Systems Society
• /
• v.8 no.4
• /
• pp.9-16
• /
• 2011

Because of the increasing demand on the high precision and high response of a machinery, proportional control valves are widely adopted at various application fields. This paper studies on the static and dynamic characteristics of a pilot proportional pressure control valve. An experimental apparatus including hydraulic pump, variable speed inverter, pressure and flow sensors and data aquisition system was set up. And various experiments such as P-Q-V curves, step responses due to input voltage and flow rate, hysteresis, frequency response of the proportional valve was carried out and the results are discussed.

• International Journal of Control, Automation, and Systems
• /
• v.1 no.1
• /
• pp.76-82
• /
• 2003

This paper establishes some integral equalities formulated by zeros located in the convergence region of a Laplace transformable function. Using the definition of the Laplace transform, it shows that Laplace transformable functions have to satisfy the integral equalities in the time-domain, which can be applied to the understanding of the fundamental limitations on the control system represented by the transfer function. In the unity-feedback control scheme, another integral equality is derived on the output response of the system with open-loop poles located in the convergence region of the output function. From these integral equalities, two sufficient conditions related to undershoot and overshoot phenomena in the step response, respectively, are investigated.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.301-306
• /
• 2003

PID controller is applied mostly to two-order system. In third-order or higher- system, it's impossible to get high response quality because of having more zero point than the number of zero point being in the PID controller. To solve those, Jung & Dorf suggested a new type of PIDA controller and solved problen of a third-order system. But, as the result of getting step response using PIDA controller, rising time is very quickly but wide overshoot is happened. Beside designing PIDA controller with using CDM(Coefficient Diagram Method) suggested by shunji manabe. But, In Performance standard, CDM decreases overshoot to desired but rising time is very slow. Therefore this paper suggest a PD-PIDA controller for low overshoot with PD type Pre-compensator. This paper applied designed PD-PIDA controller to position control of 3-Phase induction motor.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1836-1840
• /
• 2003

This paper, we propose a new phase-locked loop (PLL) system with the controllable output phase, independent from the output frequency, and lock-up time. This PLL system has a dual control loop is described, the inner loop greatly improved VCO characteristic such as faster speed response as well as higher operation bandwidth, to minimize the effect of the VCO noise and the power supply variation and also get better linearity of VCO output. The main loop is the heart of this PLL which greatly improved the output frequency instability due to the external high frequency noise coupling to the input reference frequency also the main loop can control the output phase, independent from the output frequency, and reduce the lock-up time of the step frequency response. The experimental results confirm the validity of the proposed strategy.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1-6
• /
• 2003

This paper considers the problem of determining a set of stabilizing first order controller gains, for a given linear time invariant plant, that meets or exceeds closed loop step response specifications. The method utilizes two recent results: For a given system, (1) finding a set of stabilizing first order controller gains and (2) the relationship between time response (overshoot and speed) and the coefficients of the characteristic polynomial. The method allows us to extract a subset of first order controller gains that meets stability as well as time domain performance requirements. The computations involved are the intersections of two dimensional sets described by linear and quadratic inequalities in the controller design space. It is illustrated by examples.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10b
• /
• pp.385-390
• /
• 1993

It is the purpose of this paper to present a dialogical tuning method of the sampling period in fuzzy control systems. Last year, the authors gave a dialogical tuning technique of fuzzy control system under the fixed sampling period in this symposium. In the case where sampling period is chosen larger, the response of the control system is unsatisfactory, and in the case where the sampling period is smaller, ineffective control actions are repeated. The appropriate sampling period is chosen through the step response of the closed loop fuzzy control process. As the tuning technique depends on the controlled plant, it is necessary to estimate the rough characteristics of it. The authors propose a method to decide th appropriate sampling period, by inspecting the characteristics of the plant.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.04a
• /
• pp.536-542
• /
• 2002

There are two important variables in machining process control, which are feed and cutting speed. In this work, a two degree-of-freedom controller is designed and implemented to achieve on-line cutting force control and position control based on the modelling of cutting process dynamics which are established through step response test. Two schemes are proposed and implemented. The first is feed control under the constant spindle speed and spindle speed control under the constant feed speed. The second is a simultaneous control of feed and spindle speed. The last performs a position control under the constant cutting force. Those are confirmed to work properly. Especially the latter shows a faster response.