• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.6
• /
• pp.1542-1550
• /
• 1994

For a class of singularly perturbed uncertain system, an output feedback control law is designed. The controller structure is designed based on the uncertain reduced-order system, and the controller parameters are determined by information on the reduced-order and full-order systems. It has been shown that the reduces-order system with the designed controller possesses a stability property(specifically, a global uniform attractivity). Furthermore, the stability property of this control scheme is robust with respect to singular perturbation ; i.e., the full-order system, subject to the same controller, possesses the global uniform attractivity, provided the singular perturbation parameter $\mu<\mu^{*}$, where a threshold value $\mu^{*}$ can be computed from the information available on the full-order system.

• Proceedings of the KIEE Conference
• /
• 1998.07b
• /
• pp.458-460
• /
• 1998

The drum level control is initiated by 1-element manual control, and then the control mode is changed to 1-element automatic control mode. Finally, the drum level control is changed to 3-element automatic control mode by the logic based on pre-defined threshold of main steam flow. In terms of plant automation, the automatic 1-element control mode is required from the start-up of boiler. In this paper, the fuzzy controller is adopted for automatic 1-element control of drum level from start-up. It is suggested that the fuzzy controller is used in 1-element control, and the fuzzy-PI cascade controller is used in 3-element control. Finally, the validity of suggested control scheme is shown via simulation.

• Journal of Auto-vehicle Safety Association
• /
• v.11 no.2
• /
• pp.11-16
• /
• 2019

This paper suggests an algorithm for detecting fault of longitudinal controller in autonomous vehicles. Guaranteeing safety in fault situation is essential because electronic devices in vehicle are dependent each other. Several methods like alarm to driver, ceding control to driver, and emergency stop are considered to cope with fault. This research investigates the fault monitoring process in fail-safe system, for controller which is responsible for accelerating and decelerating control in vehicle. Residual is computed using desired acceleration control command and actual acceleration, and detection of its abnormal increase leads to the decision that system has fault. Before computing residual for controller, health monitoring process of acceleration signal is performed using hardware and analytic redundancy. In fault monitoring process for controller, a process model which is fitted using driving data is considered to improve the performance. This algorithm is simulated via MATLAB tool to verify performance.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.6
• /
• pp.1114-1116
• /
• 2015

In this paper, we propose a load distribution scheme in SDN utilizing load redirection, enabling incoming messages to be migrated to another controller. Specifically, when the capacity of a controller reaches a threshold, the controller makes incoming packets be migrated to a less-loaded controller to prevent them from being blocked. Analytical result shows that our scheme has lower blocking probability than the conventional scheme.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.4
• /
• pp.275-277
• /
• 2013

Thin-film transistors(TFTs) with silicon zinc tin oxide(SZTO) channel layer are fabricated by solution-process. The threshold voltage ($V_{th}$) shifted toward positive directly with increasing Si contents in SZTO system. Because the Si has a lower standard electrode potential (SEP) than Sn, Zn, thus degenerate the oxygen vacancy (VO). As a result, the Si act as carrier suppressor and oxygen binder in the SZTO as well as a $V_{th}$ controller.

• Journal of Information Display
• /
• v.3 no.3
• /
• pp.35-43
• /
• 2002

Silicon-based 0.69-inch AMOEL microdisplay with integrated driver and timing controller circuits for microdisplay applications has been developed using 0.35 ${\mu}m$ l-poly 4-metal standard CMOS process with 5 V CMOS devices and CMP (Chemical Mechanical Polishing) technology. To reduce the large data programming time consumed in a conventional current programming pixel circuit technique and to achieve uniform display, de-amplifying current mirror pixel circuit and the current-mode data driver circuit with threshold roltage compensation are proposed. The proposed current-mode data driver circuit is inherently immune to the ground-bouncing effect. The Monte-Carlo simulation results show that the proposed current-mode data driver circuit has channel-to-channel non-uniformity of less than ${\pm}$0.6 LSB under ${\pm}$70 mV threshold voltage variaions for both NMOS and PMOS transistors, which gives very good display uniformity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.9
• /
• pp.697-700
• /
• 2011

Thin-film transistors(TFTs) with magnesium zinc tin oxide(MZTO) channel layer are fabricated by solution-process. The threshold voltage (Vth) shifted toward positive directly with increasing Mg contents in MZTO system. Because the Mg has a lower standard electrode potential (SEP) than Sn, Zn, thus degenerate the oxygen vacancy ($V_O$). As a result, the Mg act as carrier suppressor and oxygen binder in the MZTO as well as a Vth controller.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.8 no.2
• /
• pp.45-52
• /
• 2009

The off-state impedance of LED signal head is greater than that of a traditional bulb signal head, and the traffic controller has inherent off-state output leakage current. These two characteristics make the field trouble and reduce signal safety when the LED signal head is installed with traffic controller. In this Paper, a complement method of the LED signal head and traffic controller local standard (220vac line voltage) for improving signal safety is suggested. The point of designed complement method is to reduce the output leakage current of the traffic controller under 3mA, to increase the voltage feedback threshold to $70{\pm}5V$, and to make LED signal head maintain off-state in 0-95vac with 10Kohm maximum impedance.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.685-692
• /
• 2011

DC/DC switching power converters produce DC output voltages from different DC input sources. The converters can be used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The current mode DC/DC converter is composed of a PWM (pulse width modulation) controller, a MOSFET, and inductor, etc. Pulse width modulation is applied to control and regulate the total output voltage. It is shown that the variation of threshold voltage at MOSFET and the offset voltage increase caused by radiation effects make the PWM pulse unstable. In the PWM operation, the missing pulses, the changes in pulse width, and a change in the period of the output waveform are studied by simulation program with integrated circuit emphasis (SPICE) and experiments.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.12
• /
• pp.60-70
• /
• 1999

An efficient automatic inspection system for Floating Seal is developed, The proposed system consists of a high resolution line scan camera, microcomputer, and PLC (Programmable Logic Controller). In order to perform rapid inspection, The ROI (Region of Interest) is extracted from the original image. There are types of defects; shape defects and surface defects. Each features of defects are captured by edge detect, segmentation, morphological operation, and threshold analysis. PLC controller is used to synchronize the whole system and store the inspection results temporarily to reduce the overhead of microcomputer. As a result, the system is being utilized successfully in a teal inspection line.