• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.263-271
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• 2013

A low dropout regulator (LDO) with fast transient responses is presented. The proposed LDO eliminates the trade-off between slew rate and unity gain bandwidth, which are the key parameters for fast transient responses. In the proposed buffer, by changing the slew current path, the slew rate and unity gain bandwidth can be controlled independently. Implemented in $0.18-{\mu}m$ high voltage CMOS, the proposed LDO shows up to 200 mA load current with 0.2 V dropout voltage for $1{\mu}F$ output capacitance. The measured maximum transient output voltage variation, minimum quiescent current at no load condition, and maximum unity gain frequency are 24 mV, $7.5{\mu}A$, and higher than 1 MHz, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.1
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• pp.60-67
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• 2000

An experimental investigation on transient heat transfer phenomena of impinging diesel-spray on a flat plate in a pressurized chamber is carried out. A diesel spray is injected from a single-hole nozzle and impinges to a heated flat plate in the chamber. A fast-response thermocouple installed in the top surface of the plate measures the transient variation of surface temperature of the plate under various conditions of the chamber pressures. Utilizing the semi-infinite model, the temporal variation of the heat flux on the plate is determined. Effects of various parameters, such as vertical distances between the nozzle and the plate, radial distances from the injection-axis, and the chamber pressures, on the heat flux characteristics of impinging diesel-spray are studied.

• Journal of the Korean Institute of Navigation
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• v.24 no.3
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• pp.141-145
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• 2000

In servo-system which need fast response and accuracy, PID controller has a good steady-state performance, but has a poor transient response performance causing a load be changed. Compared to these features, FLC(Fuzzy Logic Controller) has a good transient response performance for changed load, but has a little Poor steady-state performance. In this paper, Compensated Fuzay Controller which consists of PID controller and FLC is proposed to modify these disadvantages and is examined through simulation to evaluate its functions.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.686-690
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• 2004

This paper describes the performance improvement of transient response and the modeling of small aircraft onboard generator. As the characteristics of the stator coil which are a major parameters of transient response were improved, the characteristics of transient response could be increased, therefore, the improved generator can be satisfied with large and fast load changes. Established the control model of the generator, it could be possible to do the analysis of generator performance, and improve the operational stability of the generator system using the control model.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.66-66
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• 2012

We describe the space project of Ultra-Fast Flash Observatory (UFFO), which will observe early optical photons from gamma-ray bursts (GRBs) with a sub-second optical response, for the first time. The UFFO will probe the early optical rise of GRBs, opening a completely new frontier in GRB and transient studies, using a fast-response rotatable mirror system which redirects opitical path to telescope instead of slewing of telescopes or spacecraft. In our small UFFO-Pathfinder experiment, scheduled to launch aboard the Lomonosov satellite in June 2012, we use a motorized mirror in our Slewing Mirror Telescope instrument to achieve less than one second optical response after X-ray trigger. We describe the science and the mission of the UFFO project, including a serious version called UFFO-100 which will be launched in 2014. With our program of ultra-fast optical response GRB observatories, we aim to gain a deeper understanding of GRB mechanisms, and potentially open up the z>10 universe to study via GRB as point source emission probes.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.8
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• pp.136-143
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• 2007

A improved current controller with reference modification part that has both fast transient response in transient state and high accuracy in steady state is proposed. In this scheme, a improved reference modification part is used to synchronous frame PI controller for the fast transient state. The transient response of current controller is seriously deteriorated in high back e.m.f.(electromotive force) due to the lack of DC link control voltage. This paper is proposed that the improved reference modification part is compared with voltage limit and reference voltage.

• Journal of IKEEE
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• v.25 no.1
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• pp.201-205
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• 2021

In this paper present Low Drop-Out (LDO) regulator that improved load transient characteristics due to the push-pull detection structure. The response characteristic of the voltage delta value is improved due to the proposed push-pull sensing circuit structure between the input terminal of the LDO regulator pass transistor and the output terminal of the internal error amplifier. Voltage value has improved load transient characteristics than conventional LDO regulator. Compared to the conventional LDO regulator, it has an improved response speed of approximately 244 ns at rising time and approximately 90 ns at falling time. The proposed circuit was simulated by the samsung 0.13um process using Cadence's Specter and Virtuoso simulator.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3801-3807
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• 2023

Outcomes of the project "Comprehensive Verification of the FALCON Code for Calculation of Nuclear Fuel Temperature" relating to calculation of fuel temperature during relatively fast thermal transients are presented. Good prediction capabilities of the FALCON MOD01 code coupled with the GRSW-A code are shown as applied to the data of the TF3 and TF5 tests from the Transient Temperature Experiment IFA-507. The IFA-507 related dataset of the OECD/NEA International Fuel Performance Experiments (IFPE) Database is extended by the reconstructed dynamics of the axial power distribution in the rods during the transient phase of the experiment. Based on the code calculation, the time constant of the thermal fuel response to a power transient is estimated.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1654-1659
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• 2003

This paper introduces a fast Fourier transform (FFT)-based spectral analysis method for the transient responses as well as the steady-state responses of linear discrete systems. The force vibration of a viscously damped three-DOF system is considered as the illustrative numerical example. The proposed spectral analysis method is evaluated by comparing with the exact analytical solutions as well as with the numerical solutions obtained by the Runge-Kutta method.

• Journal of Power Electronics
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• v.4 no.2
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• pp.87-95
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• 2004

A new fast-response high-current clamp DC-DC converter circuit design is presented that will meet the requirements and features of the new generation of microprocessors and digital systems. The clamp in the proposed converter amplifies the current in case of severe load changes and is able to produce high slew rate of output current and capability to keep constant the output voltage. This proposed high-current clamp technique is theoretically loss less, low cost and easy to implement with simple control scheme. This is modified from a basic buck topology by replacing the output inductor with two magnetically coupled inductors. Inductors are difference in inductance, one has large inductance and other has small inductance. The inductor with small inductance will take over the output inductor during fast load transient. It speedup the output current slew rate and reduce the output voltage drop in the case of heavy burden load changes.