• International Journal of Control, Automation, and Systems
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• v.1 no.2
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• pp.210-214
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• 2003

This paper presents a residence time distribution (RTD) measurement method using a radioisotope tracer and the estimation method of RTD model parameters to analyze a submerged bio-reactor. The mathematical RTD models have been investigated to represent the flow behavior and the existence of stagnant regions in the reactor. Knowing the parameters of the RTD model is important for understanding the mixing characteristics of a reactor The radioisotope tracer experiment was carried out by injecting a radioisotope tracer as a pulse into the inlet of the reactor and recording the change of its concentration at the outlet of the reactor to obtain the experimental RTD response. The parameter estimation was performed by the Levenberg-Marquardt optimization algorithm. The proposed scheme allowed the parameter estimation of RTD model suggested by Adler-Hovorka with very low deviations. The estimation procedure is shown to lead to accurate estimation of the RTD parameters and to a good agreement between experimental and simulated response.

• Smart Structures and Systems
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• v.29 no.3
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• pp.485-498
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• 2022

In near-fault earthquake prone areas, the velocity pulse-like seismic waves often results in excessive horizontal displacement for structures, which may result in severe structural failure during large or near-fault earthquakes. The recently developed isolator-gap damper (IGD) systems provide a solution for the large horizontal displacement of long period base-isolated structures. However, the hysteresis characteristics of the IGD system are significantly different from the traditional hysteretic behavior. At present, the hysteretic behavior is difficult to be reflected in the structural analysis and performance evaluation especially under random earthquake excitations for lacking of effective analysis models which prevent the application of this kind of IGD system. In this paper, we propose a mathematical hysteretic model for the IGD system that presents its nonlinear hysteretic characteristics. The equivalent linearization is conducted on this nonlinear model, which requires the variances of the IGD responses. The covariance matrix for the responses of the structure and the IGD system is obtained for random earthquake excitations represented by the Kanai-Tajimi spectrum by solving the Lyapunov equation. The responses obtained by the equivalent linearization are verified in comparison with the nonlinear responses by the Monte Carlo simulation (MCS) analysis for random earthquake excitations.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.267-270
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• 1997

Oxygen saturation is an important parameter in clinical fields; fetal monitoring, apnea, emergency medicine etc. Because of monitoring patients continuously, pulse oximeter that measures oxigen saturation non-invasively is regarded attentively. But, though research about accuracy of signal extraction has been developed, it actually plays a supplementary part in hospital for not trusting the principle of measurement by clinicians. In this paper focusing on these things, first we suggested simple mathematical modelling on separating do components, ac components andnoise components in optical signal transmitted from fingertip or earlobe, and then we considered oxygen saturation computing algorithm using integral ratio of pulsating components. Last, we analyzed its effect by comparing received data.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.151-154
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• 2002

In this paper a mathematical model, the results of computer simulation and exprimental investigations of electrochemical machining with a too-electrode are presented. The experimental investigations were carried out in order to evaluate the influence of working voltage, initial interelectrode gap size, and metal remove rate. Accuracy of computer simulation evaluated by differences between results of experimental test and computer simulation depends on electrochemical machining coefficient, total overpotential of electrode process, current density, electrical conductivity of electrolyte, and etc. Metal removal rate would be predicted by the simulation of ECM process.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.12-14
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• 1994

In industrial drive of the BDCW motor, voltage source inverter is of tenly used. In this paper in operation of the inverter for the BDCM drives, some PWM techniques are applied and the mathematical torque ripple model is developed to investigate the performance of the PWM techniques. The simulation results show that the multiple pulse modulation is practically introduces the lowest torque ripple components.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2678-2680
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• 2000

In this paper, we calculates mathematical model of ex-core neutron flux monitoring system for nuclear reactor and design the digital system using the bilinear transformations. The output pulse shape and resolving time of the system determines from the proposed method.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1114-1123
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• 2017

A linear permanent-magnet vernier (LPMV) motor has magnets and windings in the short mover, which is very suitable for long stroke applications. This paper proposed a new field oriented control with space vector pulse width modulation for the LPMV motor, which considers loss minimization. First, the topology of the LPMV motor is briefly presented. Then, the mathematical model is derived, and the mover field oriented control strategy is proposed. Also, the loss analysis is performed. Finally, the simulated and experimental results are given, verifying the feasibility and effectiveness of the proposed control strategy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.720-725
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• 2000

A new ultrasonic pulse-echo technique was developed and described for vibration measurement of the suspension assembly in hard disk drives. The method is based upon the difference in magnitude of two consecutive reflection waves from a moving object(suspension), while the traditional ultrasonic vibrometer uses the phase shift of the reference wave and the reflection wave. A cone-shape delay line is designed to access the small structure. A simple mathematical model is presented and analyzed with experimental results to show the feasibility of the method. The advantages of this ultrasonic vibration measurement method are relatively high resolution, low cost, and ease of implementation comparing with the Laser Doppler vibrometer.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.16-24
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• 2005

Mathematical model was developed to verify a sequential particle removal taking place in a granular media gravity filter. Consequential multi-layer filtration cycle model was applied to verify the fraction of filter effluent particles that are filter influent particles that were never removed as well as the fraction of filter effluent particles that were detached after deposition were performed through laboratory experiments. Three sizes of marker particles were injected ahead of the filter column as a pulse in the presence of four sizes of polystyrene particles that were used as a primary source of particles in the raw suspension to investigate particle attachment alone in contrast to net removal from attachment and detachment. Microscopic counting of filter effluent particles was assumed to reflect attachment. Experimental results indicated that particle detachment is significant beginning from the early phase of filtration. For each size of fluorescent microspheres at one filter depth, fluorescent microsphere removal increased with filter runtime to a maximum due to ripening. The detached fraction of effluent particles increased with particle size and filter depth. The presence of detached particles and the increasing fraction of detached particles in deeper bed were confirmed.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.2
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• pp.95-101
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• 2006

A fuel metering unit using PWM(Pulse Width Modulated) solenoid valve has some advantages such as low cost, small size and simple structure. The mathematical model and its experimental rig of the fuel metering unit using PWM solenoid valve and CPDV(Constant Pressure Drop Valve) for miniature turbo engines were constructed. As the results of simulation, some major parameters which have dominant effects on the performance were found. And the experimental results verified the validity of established model by showing the good agreement with the numerical simulation results. Hence, this system modeling could be used effectively in the actual development of a PWM fuel control system.