• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.4
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• pp.205-211
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• 2003

In this paper we propose a disturbance design method to test a system's stability. It is shown that the time maximum disturbance is represented in bang-bang and state feedback form. To maximize the time severity index, the value of disturbance is determined by the associated switch curve. The original switch curve is vulnerable to model uncertainties and takes much calculation time. We propose an improved method to approximate the original switch curve. This reduces the computational time and implements sufficiently to test the stable system. Simulation results show how the approximate switch curve can be used to stress a system by driving it to oscillation along the maximum limit cycle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.804-807
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• 2005

In this paper, a double scotch yoke mechanism for moving simultaneously the fixed contact and moving contact of a gas circuit brake, is proposed and designed to improve the breaking characteristics of the circuit breaker. Firstly, the design parameters of the scotch yoke are kinematically determined from the desired design condition of the circuit breaker. Next, the stroke curve of the moving contact is designed by considering the design parameter and the specified opening characteristics of electric contacts. Based on the scotch yoke and stroke curve, the dynamics of the electric contacts is analyzed using ADAMS model of switch mechanism.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1187-1190
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• 2009

CURVE SQUEAL NOISE IS THE INTENSE HIGH FREQUENCY TONAL THAT CAN OCCUR WHEN A RAILWAY VEHICLE TRAVERSES A CURVE OR A SWITCH. THE HIGH NOISE LEVEL CAUSES ANNOYANCE FOR PEOPLE WHO LIVE IN THE NEIGHBOURHOOD OF THE SQUEALING RAILWAY TRACK AS WELL AS FOR THE PASSENGERS IN CARS WITH CURVES. THIS PAPER EXAMINES THE SPECTRAL SOUND DISTRIBUTION IN CURVES FOR KTX TRAIN. THE FREQUENCY RANGE IS FROM AROUND 4,000 TO ALMOST 16,000Hz, WITH NOISE LEVELS UP TO 92dB IN CURVE R400.

• Journal of Electrical Engineering and Technology
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• v.5 no.3
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• pp.484-492
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• 2010

Magnetic switch is a kind of saturable inductor, which utilizes nonlinearity of the magnetization curve of ferromagnetic materials. The right understanding of the saturation phenomena, magnetic properties, voltage-time product, and switching characteristics of the magnetic switch is essential in designing the magnetic pulse compressor (MPC). In this paper, the historical background of research on the MPC, fundamental physical properties of the magnetic switches, and application fields of the MPC are presented. Further, an in-depth analysis of pulse compression in series and parallel MPCs is incorporated. As practical application examples, a series MPC used for water treatments and a parallel MPC used for pulsed electric field (PEF) inactivation of bacteria are cited.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.12
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• pp.1152-1159
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• 2013

This paper proposes an effective walking system for a hexapod robot on uneven terrain. To overcome the deficiencies of two-pair walking systems, which are effective on even terrain, the use of only three legs changes the steps required for movement. The proposed system receives feedback data from switches attached to the bottom of the legs and gyro sensor to carry out stable walking using the Bezier curve algorithm. From the coordinates of the Bezier curve, which guarantees the circular motion of legs, the motor's angle value can be obtained using inverse kinematics. The angle values are sent to each motor though RS-485 communication. If a switch is pushed by the surface during navigation in the Bezier curve pattern, the robot is designed to change its circular course. Through the changed course, each leg can be located on an optimal surface and the wobble phenomenon is reduced by using a normal vector algorithm. The simulation and experiment results show the efficiency of the proposed algorithm.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.6
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• pp.584-591
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• 2000

Power Quality Compensator(PQC) has been installed to protect the sensitive loads against the voltage disturbances, such as voltage sag and interruption. In general, static switch is used for the purpose of link between utility and PQC. So transfer operation of the static switch play a important part in the PQC. Many studies on the structure and control of PQC have been progressed in active, but these researches have been rarely mentioned about any voltage-disturbances-detection method to start the PQC operation. In this paper, a new voltage-disturbances-detection algorithm for computer application loads using the CBEMA/ITIC curve is proposed for transfer operation of the static switch. The proposed detection algorithm is implemented to get fast detecting time through the comparison of instantaneous 3-phase voltage values transferred to DC values in the synchronous reference frame with the operating reference values. To get the robust characteristics against the noise, a first order digital filter is designed. The magnitude falling and phase delay caused by the filter are compensated through the error normalizing and numerical analysis using transfer function, respectively. Finally, the validity of the proposed algorithm is proved by ACSL simulation and experimental results.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.219-226
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• 2022

In this experimental study, the effect of continuously changing the position of electromagnetic force using several coils and a relay switch on fracture energy was investigated. Normal mortar and steel slag mortar specimens in which 50 % and 100 % of sand was replaced with steel slag were cast and exposed to electromagnetic field. The electric field was induced by one coil without a relay switch as an existing method and by partitioning the coil and continuously changing the position using a relay switch. The fracture energy was calculated from the load-vertical displacement curve obtained from the experiment and compared with each other. As a result of the experiment, it was confirmed that the method of partitioning the coil and changing the position of electromagnetic force by using a relay switch is effective in increasing the fracture energy even if the same amount of power is used.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.3
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• pp.313-321
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• 2014

A low-power low-cost polar transmitter for EDGE is designed in $0.18{\mu}m$ CMOS. A differential delta-sigma modulator (DSM) tunes a three-terminal voltage-controlled oscillator (VCO) to perform RF phase modulation, where the VCO tuning curve is digitally pre-compensated for high linearity and the carrier frequency is calibrated by a dual-mode low-power frequency-locked loop (FLL). A digital intermediate-frequency (IF) pulse-width5 modulator (PWM) drives a complementary power-switch followed by an LC filter to achieve envelope modulation with high efficiency. The proposed transmitter with 9mW power dissipation relaxes the time alignment between the phase and envelope modulations, and achieves an error vector magnitude (EVM) of 4% and phase noise of -123dBc/Hz at 400kHz offset frequency.

• Journal of Chest Surgery
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• v.26 no.1
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• pp.36-43
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• 1993

Sixty four children [aged 2 days to 9 years] , 58 with complete transposition of the great arteries, 5 with Taussig-Bing double outlet right ventricle, and 1 with double outlet left ventricle plus left ventricular type single ventricle, have undergone anatomic correction from November 1987 to August 1992. Eleven underwent previous operations: pulmonary artery banding[7], modified Blalock-Taussig shunt[2], coarctoplasty[2], aortic arch reconstruction[1] . Of 58 patients with TGA, Type A coronary arteries of Yacoub were seen in 50[86%]. U-shaped coroanry arterial flaps were transfered to the neoaorta using trap door technique, and neopulmonary arterial tract was constructed using glutaraldehyde fixed autopericardium with Lecompte maneuver. There were 18 hospital deaths [28.1%] with no late mortality. Mean follow-up of 20.4\ulcorner11.9 months were achieved in all survivors. Postoperative cardiac catheterizations were done in 14 cases. Mean pressure gradients of pulmonary and aortic outflow tract were 15.0 $\pm$2.6 and 4.2$\pm$1.4mmHg, mild aortic valve insufficiencies were found in 2, and mean cardiac index was 5.18$\pm$0.19 L/min/M2. We conclude that we should continue anatomic correction for the complex congenital heart anomalies with the malposition of the great arteries because myocardial function seems to be well preserved, though we are still on the learning curve.

• Journal of Photoscience
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• v.11 no.32
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• pp.71-74
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• 2004

The macrocycle L exhibited a switch on-off behavior through the fluorescent responses by aromatic imine molecule 1 (X=H) / trifluoroacetic acid (TFA). In the 'switch on' state, it was supposed that the aromatic imine molecule 1 is in the cavity of macrocycle L and a photoinduced electron transfer (PET) from the nitrogen of azacrown part to the anthryl group is inhibited by the interaction between the aromatic imine molecule 1 and the azacrown part of macrocycle L. In the 'switch off' state, it was supposed that the protonated imine molecule 1 is induced by the continuous addition of TFA and a repulsion between the protonated azacrown part and the protonated imine molecule 1 is occurred. It was considered that this process induces the intermolecular PET from the protonated imine molecule 1 to the anthryl group of macrocycle L because of a proximity effect between the anthryl group and the protonated imine molecule 1. From the investigation of the transient emission decay curve, the macrocycle L showed three components (3.45 ns (79.72%), 0.61 ns (14.53%), and 0.10 ns (5.75%). When the imine molecule 1 was added in the macrocycle L as molar ratio=1:1, the first main component showed a little longer lifetime as 3.68 ns (82.75%) although the other two components were similar as 0.64 ns (14.28%) and 0.08 ns (2.96%). On the contrary, when the imine molecule 3 (X=C1) was added in the macrocycle L as molar ratio=l:1, all the three components were decreased such as 3.27 ns (69.83%), 0.44 ns (13.24%), and 0.06 ns (16.93%). The fluorescent pH titration of macrocycle L was carried out from pH=3 to pH=9. The macrocycle L and C $U^{2+}$- macrocycle L complex were intersected at about pH=5, while the E $u^{3+}$ -macrocycle L complex was intersected at about pH=5.5. In addtion, we investigated the fluorescence change of macrocycle L as a function of the substituent constant ($\sigma$$_{p}$$^{o}$) showing in the para-substituent with electron withdrawing groups (X=F, Cl) and electron donating groups (X=C $H_3$, OC $H_3$, N(C $H_3$)$_2$), respectively, as well as non-substituent (X=H).).ctively, as well as non-substituent (X=H).