• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.145-148
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• 1990

In this paper, the problem of designing a feedback controller for a robotic manipulator, which is activated by a D.C. motor through a gear train and a flexible shaft or chain, is considered. When the response of the closed loop control system is relatively slow, a satisfactory controller may be designed as a PID controller. As the speed of the control system increases, however, the spring effect of the linkage becomes profound, and as a result, the transient response exhibits a substantial oscillation. To eliminate this oscillation, it is necessary to design the controller based on at least a fourth order system model. This, in turn, requires the feedback of the entire state variables. In practice, however, only the position of the manipulator and the velocity of the motor are readily measurable. The state variable reconstruction method or a state observer cannot be used because of the system nonlinearities such as the Coulomb frictions. In this study, an alternative controller, which is based on delayed feedback of the output variable only, is proposed, and a successful delayed feedback controller is designed and implemented on an actual experimental manipulator.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.327-329
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• 1997

Current was generated from monolayers on a air/water surface by monolayer compression, and the measuring technique has been applied to the study on monolayers of Arachidic acid and the range of gas state, gas/fuid state and fluid state in the course of monolayer compression. Also, we measured that compression veloecity(30, 40, 50mm/min) when the sample's spread volume was about $500{\mu}{\ell}$ of sample. From the result, it is known that current is generated in the range of high surface pressures as compression velocity become faster.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.3
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• pp.615-619
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• 2007

In this study, the MCC(modified Cam-Clay) model and the Hvorslev-MCC model, recently developed based on the critical state theory and with relatively few model parameters, were investigated by comparing the model predictions with the result of the conventional triaxial compression test strictly performed in laboratory. The discrepancy of the prediction capacities of the models exists on the heavily over-consolidated specimen. The Hvorslev-MCC model accurately predicts the peak strength envelope for heavily over-consolidated clayey specimens on the dry side of the critical state since it adopts the Hvorslev surface in the supercritical region other than the ellipse of the MCC model.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.212-214
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• 2002

Existence of leverage points was claimed to be the reason for the WLAV estimator failing to reject bad data in the measurements. This paper presents an impact of leverage points on the result of power system state estimation. State estimator is run with measurement sets with gross error and leverage point. Three test cases are performed and the results are presented using IEEE 30 bus system.

• Korean Journal of Mathematics
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• v.12 no.1
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• pp.77-90
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• 2004

The purpose of this paper is to give a sufficient condition for the existence, nonexistence and uniqueness of coexistence of positive solutions to a rather general type of elliptic competition system of the Dirichlet problem on the bounded domain ${\Omega}$ in $R^n$. The techniques used in this paper are upper-lower solutions, maximum principles and spectrum estimates. The arguments also rely on some detailed properties for the solution of logistic equations. This result yields an algebraically computable criterion for the positive coexistence of competing species of animals in many biological models.

• Proceedings of the KOSOMBE Conference
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• v.1989 no.05
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• pp.61-65
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• 1989

In this paper, a method of the measument the degree of the musule fatigue by Short Time Fourier Analysis of the EMG signals from human biceps in the action state is proposed. For this purpose, fatigue state and recovery state of 10 persons EMG signals are sampled. And then spectrum centroids are analyzed with respect to the change of sample time window. As result of 10 persons experiment, we know that person A is most good recovery stale.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.19-22
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• 1997

This paper studies the arousal effects of aroma and warning sound using EDA(Electrodermal Activity:EDA), Aroma stimulus started at Nz value over 1.2. Warning sound was prepared according to the arousal evaluation and control criteria. As a result, the warning sound could be controlled the arousal level in all the mKSS state. Aroma stimulus was able to prevent drowsy more than warning sound in the mKSS 3 state(the first stage of drowsiness). Therefor, aroma stimulus was can be used for arousal control at that state. Futhermore, arousal control was shown to be more effective with presentation of both aroma and warning sounds than each presentation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.06a
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• pp.160-173
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• 1997

Microstructure of hypereutectic Al-17wt.% Si alloy, fabricated by mechanical stirring and by reheating at semi-solid state, was investigated by optical microscope. Flow behavior semi-solid metal also was investigated at diffentent mould temperatures 280$^{\circ}C$, 290$^{\circ}C$ and 300$^{\circ}C$. Size of silicon particles were increased over 100$\mu\textrm{m}$ during solidification as a result of stirring. It is considered as microstructural coarsening by bonding between neighbouring primary silion particles during stirring of slurry. In case of reheating at semi-solid state, however, primary silicon particle was not increased at size of 40$\mu\textrm{m}$ and nearly spherical aluminum solde particle also could be obtained uniformly in distribution. The fludity of Al-17wt.% Si alloys at semi-solid state was improved when solid fraction was 0.7 at mould temperature of 300$^{\circ}C$ than other conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.913-920
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• 1996

In this study, the counting method for multi-axial and multi-point load states was proposed. Using this counting method, the load spectrum is generated from the service load history which is measured for boom structure of excavator. Loading state for loading points of boom structure is described as a multi-dimensional state space. From this load spectrum, the stress spectrum was generated by FEM analysis using the superposition of the unit load. The cumulated damage at the severe damage point of In nm structure by the failure example is calculated by Palmgren-Miner's rule. As a result of this study, the fatigue life estimation using the multi-axial and multi-point load counting method is useful.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.166-170
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• 2008

The elder population is growing rapidly in Korea nowadays. Therefore, a demand for adaptable installation standard of residential space for the elderly is increasing with growth of the elder population. This study analyzed actual state by interviewing manager, surveying actual measurement and using draft of Elderly nursing facility which is for senile patients. As a result of the survey for size and facilities, facilities for elderly safety, accommodation per a person and room size per a person are below to standard. Therefore, establishing adaptable design standard is needed which is to make safe and fresh living environment for the elderly.