• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.256-261
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• 2004

This paper presents a simple two-degree of freedom PID tuning table based on the CDM design method. The structure of the control system will be composed of plant, P or PI or PID controller and a pre-filter. The finalized formula can be used based on the experimental test of the plant in the same manner as the Ziegler-Nichols' second method. That is; users just need to find the critical gain and critical period experimentally and the parameters of the P, PI or PID controller with the pre-filter can be obtained by substituting the values of critical gain and critical period in the tuning table. The simulation results of the control systems utilizing the proposed controllers compared with those using the Ziegler-Nichols' second method will also be demonstrated.

• Ocean Systems Engineering
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• v.10 no.2
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• pp.131-161
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• 2020

The objective of this study was to evaluate the downtime cost of side-by-side offloading operations in Malaysian waters. With the help of a numerical time domain tool, the structure and cable response of moored FPSO vessel was simulated for heading and beam sea-states under irregular waves. The weather downtime was assessed by comparing the response under operational wave condition with the pre defined industrial safe offloading criteria. Additionally, two cases of cable failure were simulated for each sea-state. The novel study on downtime cost was presented for three different location of Malaysia subcontinent for which the location specific wave scatter diagram facilitated to estimate the probability of occurrence of operational wave condition. It was concluded that an unpredictable increment in wave height by 0.5 m can significantly impact the production cost.

• Transactions of Materials Processing
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• v.17 no.7
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• pp.466-472
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• 2008

In this paper, tension tests and formability tests are performed to construct a database related to mechanical properties and the formability of the AZ31B Mg alloy sheet. A forming test with a hemi-spherical punch is conducted at varying temperatures to establish a forming limit diagram. In order to verify the applicability of the analysis using the conventional flow hardening model, a finite element analysis is performed on the hemi-spherical punch forming process and the results are compared with experimental ones. The study investigates problems involving a computational analysis that does not consider flow softening of the magnesium alloy at elevated temperatures.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.1
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• pp.17-25
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• 2005

This paper provides sufficient conditions for the robustness of Affine linear TFM(Transfer Function Matrix) MIMO (Multi-Input Multi-Output) uncertain systems based on Rosenbrock's DNA (Direct Nyquist Array). The parametric uncertainty is modeled through a Affine TFM MIMO description, and the unstructured uncertainty through a bounded perturbation of Affine polynomials. Gershgorin's theorem and concepts of diagonal dominance and GB(Gershgorin Bands) are extended to include model uncertainty. For this type of parametric robust performance we show robustness of the Affine TFM systems using Nyquist diagram and GB, DNA(Direct Nyquist Array). Multiloop PI/PB controllers can be tuned by using a modified version of the Ziegler-Nickels (ZN) relations. Simulation examples show the performance and efficiency of the proposed multiloop design method.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.549-553
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• 2003

SMB(simulated moving bed) chromatography system has been developed to realize continuous separation and save solvent consumption for binary mixture such as chiral compounds in especial. The parameters of SMB chromatography system can be calculated from mass balance equations of true moving bed chromatography, and they are used in design of 6-column SMB chromatography. We can separate 1'R-25 and 1'S-2S enantiomers as a raffinate product in 95% of purity using assembled SMB chromatography system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.877-882
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• 2005

Dynamic stability of an axially accelerating beam stucture is investigated in this paper. The equations of motion of a fixed-free beam are derived using the hybrid deformation variable method and the assumed mode method. Unstable regions due to periodical acceleration are obtained by using the Floquet's theory. Stability diagrams are presented to illustrate the influence of the dimensionless acceleration, amplitude, and frequency. Also, buckling occurs when the acceleration exceeds a certain value. It is found that relatively targe unstable regions exist around the first bending natural frequency, twice the first bending natural frequency, and twice the second bending natural frequency. The validity of the stability diagram is confirmed by direct numerical integration of the equations of motion.

• The Korean Journal of Applied Statistics
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• v.24 no.6
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• pp.1021-1031
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• 2011

Equity linked securities are indirect investments where the return of investment depends on the performance of the underlying equities. In this paper, we review the profit structure of typical equity linked securities through a profit diagram and investigate which characteristics of time series at the investment affect the early repayment of the stepdown ELS based on KOSPI 200 and HSI. We also compare VaRs using the empirical distribution function for risk management.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.46-49
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• 2004

The spider of a drum washing machine receives the repeated fatigue loadings during laundering. Although the spider is designed statically safely, it often happens fatigue failure. Therefore it requires the safe design for fatigue and needs the prediction of quantitative fatigue life. The S-N diagram for a spider material is developed by fatigue test and statistical analysis. The stresses are measured directly from strain gages on the spider. To predict the fatigue life of spider, the rainflow counting method and Miner's rule are used. The data for fatigue life are analyzed statistically. From these data, reliability estimation for fatigue life can be done and also, equivalent fatigue life can be obtained. It will be applied to make and improve to a short period for design and prototype test.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.1
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• pp.1-8
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• 1994

This study carried out to investigate the spray characteristics of diesel oil through out ultrasonic fuel supply system in comparison with conventional. Size of the droplets comprising diesel spray was measured by immersed liquid method at different positions along the spray axis. Droplets distribution diagram was ploted and Sauter Mean Diameter(SMD) was also calculated. The effects of the ultrasonic vibration and injection pressure on the droplet size distribution and SMD were investigated. As the ultrasonic vibration supply SMD decreases on the same injection pressure conditions with conventional injector's. But the effect of ultrasonic vibration decreases with injection pressure increasing.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.478-480
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• 2008

On this paper, digitally controlled push-pull dc-dc converter and dc-ac inverter for induction motor control are presented, which is used one DSP(digital signal processor). This system has 12V battery input for the push-pull converter, and the push-pull converter generates 300V output for induction motor inverter input. In order to compensate the push-pull converter, the transfer function of push-pull converter is derived and digital PI compensator is adapted. Through bode diagram, stability of digital controlled push-pull converter is analyzed. To verify the proposed system, digital simulation of the induction motor drive using digital push-pull converter are performed.