• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.05a
• /
• pp.461-466
• /
• 2005

This paper presents a new speed control scheme of the spindle induction motor (IM) using fuzzy-logic control in fold weakening region. The implementation of the proposed FLC-based spindle IM are investigated and compared to those obtained from the conventional PI controller based drive system, we have confirmed good simulation and experimental results at different dynamic operating conditions such as sudden change in command speed, step change, etc.

• Journal of Power System Engineering
• /
• v.19 no.5
• /
• pp.93-98
• /
• 2015

Nuclear power plants has a number of valves, which are operating at a high temperature-high pressure and radiation environment conditions. Nevertheless, it is important to maintain the reliability of the valves to ensure safe operation of the nuclear power plant. However, the aging of the valves by increasing of years of plant operation and the system transients due to the sudden load change are working the failures of the reliability of the valve. In this paper, we evaluate experimentally the performance change according to the thermal aging of the valve. Results show that the valve stem and the actuator leakages were enlarged by the thermal aging.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1991.10a
• /
• pp.64-68
• /
• 1991

It happened that there was a sudden peak with the capacity of change, when I measured the capacity of change, cubical expansion and Thermally Stimulated Current on the Cross - Linked Polythylene. Crystal melting began at 375 K and changed into formaless shapeless at 380 K. The conduct of a particle on the surfase of dipole, electron trap was founded to be ion conduction nature under the low electronic field, wherase, the electron nature under the high electronic field. Consequentity, under the semi-conduction layer electronic a particle was injected to inter-fase and accumulated for a time and appeared to be TSC.

• Proceedings of the KIPE Conference
• /
• 2004.07a
• /
• pp.303-307
• /
• 2004

This paper presents a new speed control scheme of the spindle induction motor (IM) using fuzzy-logic control in field weakening region. The implementation of the proposed FLC-based spindle IM are investigated and compared to those obtained from the conventional PI controller based drive system, we have confirmed good simulation and experimental results at different dynamic operating conditions such as sudden change in command speed, step change, etc.

• Journal of Sensor Science and Technology
• /
• v.16 no.6
• /
• pp.467-474
• /
• 2007

The real-time monitoring about the activity of the human provides useful information about the activity quantity and ability. The present study implemented a small-size and low-power acceleration monitoring system for convenient monitoring of activity quantity and recognition of emergent situations such as falling during daily life. For the wireless transmission of acceleration sensor signal, we developed a wireless transmission system based on a wireless sensor network. In addition, we developed a program for storing and monitoring wirelessly transmitted signals on PC in real-time. The performance of the implemented system was evaluated by assessing the output characteristic of the system according to the change of posture, and parameters and acontext recognition algorithm were developed in order to monitor activity volume during daily life and to recognize emergent situations such as falling. In particular, recognition error in the sudden change of acceleration was minimized by the application of a falling correction algorithm

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 2001.05a
• /
• pp.300-310
• /
• 2001

In this paper, new gamut-mapping algorithm (GMA) that utilizes variable anchor points (center of gravity on the luminance axis) is proposed. The proposed algorithm increases luminance range, which is reduced from conventional gamut mapping toward an anchor point. In this process, this algorithm utilizes multiple anchor points with constant slopes to both reduce a sudden color change on the gamut boundary of the printer and to maintain a uniform color change during the mapping process. Accordingly, the proposed algorithm can reproduce high quality images with low-cost color devices.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.31 no.2
• /
• pp.15-26
• /
• 2006

In reality, we can observe anomalous diffusion patterns of cycle-recycle or rejuvenation. Abrupt changes in the market environment such as sudden currency devaluation or change in government policy or those in marketing strategies such as drastic repositioning can lead to such atypical diffusion patterns. The authors present extended Bass models that incorporate effects of such abrupt changes of external factors into the hazard rate and the market potential. Using a set of compact-car data affected by a drastic change in the government policy, they illustrate the strengths of the proposed models.

• Journal of the Korean Ceramic Society
• /
• v.43 no.9 s.292
• /
• pp.537-543
• /
• 2006

Length change, hydration heat, setting time and compressive strength of OPC were measured by adding KCl and replacing limestone powder so as to examine the influence of limestone powder on hydration of the OPC contained much chloride. In general, the chloride modified cement was high in heat of hydration, short in its setting time, low in its fluidity and low in its strength at 28 days due to the sudden hydration in its initial stage. As a result of the experiment, it has been demonstrated that heat of hydration, became low as one replaced limestone powder to the chloride modified cement, and the fluidity and shrinkage rate of mortar decreased without change in setting time; furthermore, the compressive strength at 28 days was improved.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.25 no.1
• /
• pp.29-36
• /
• 2020

In this study, a variable step algorithm is proposed on the basis of the perturb and observe method. The proposed algorithm can follow the maximum power point (MPP) quickly when solar irradiance changes rapidly. The proposed technique uses the voltage change characteristic at the MPP when the environment changes because of insolation or temperature. The MPP is tracked through the voltage control using a variable step method. This method determines the sudden change of solar irradiance by setting the threshold value and operates in fast tracking mode to track the MPP rapidly. When the operation point reaches the MPP, the mode switches to the variable step mode to minimize the steady state error. In addition, the output disturbance is decreased through the optimization of the control method design. The performance of the proposed MPPT algorithm is verified through simulation and experiment.

• Journal of Oral Medicine and Pain
• /
• v.43 no.4
• /
• pp.142-146
• /
• 2018

Patients with temporomandibular disorder often present with acute occlusal change and properly managed with conservative treatment. If such change is caused by unusual etiology, differential diagnosis may be challenged. This article describes the diagnosis of a patient exhibiting pain and acute posterior open bite on the ipsilateral side after chewing hard food. After initial conservative treatment failed to resolve the complaint, magnetic resonance imaging was ordered and confirmed partial perforation of articular disc. Disc perforation itself is usually chronic in nature, but sudden macrotrauma may also cause the disorder. However, occlusal discrepancy caused by disc perforation is rare and seldom reported. We present a case of acute malocclusion caused by disc perforation with a review of related literature.