• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.3
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• pp.326-333
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• 2015

This paper reports an adaptive positive feedback bias control technique for operational transconductance amplifiers to adjust the bias current based on the output current monitored by a current replica circuit. This technique enables operational transconductance amplifiers to quickly adapt their power consumption to various analog workloads when they are configured with negative feedback. To prove the concept, a test voltage follower is fabricated in $0.5-{\mu}m$ CMOS technology. Measurement result shows that the power consumption of the test voltage follower is approximately linearly proportional to the load capacitance, the signal frequency, and the signal amplitude for sinusoidal inputs as well as square pulses.

• Structural Engineering and Mechanics
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• v.24 no.2
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• pp.155-180
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• 2006

Many applications in mechanical design involve elastic bodies coming into contact under the action of the applied load. The distribution of the contact pressure throughout the contact interface plays an important role in the performance of the contact system. In many applications, it is desirable to minimize the maximum contact pressure or to have an approximately uniform contact pressure distribution. Such requirements can be attained through a proper design of the initial surfaces of the contacting bodies. This problem involves a combination of two disciplines, contact mechanics and shape optimization. Therefore, the objective of the present paper is to develop an integrated procedure capable of evaluating the optimal shape of contacting bodies. The adaptive incremental convex programming method is adopted to solve the contact problem, while the augmented Lagrange multiplier method is used to control the shape optimization procedure. Further, to accommodate the manufacturing requirements, surface parameterization is considered. The proposed procedure is applied to a couple of problems, with different geometry and boundary conditions, to demonstrate the efficiency and versatility of the proposed procedure.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.9
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• pp.450-453
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• 2005

A high speed address recovery technique for AC plasma display panel(PDP) is proposed. Replacing GND switch by clamping diode. the recovery speed can be increased by saving GND hold-time and switching loss due to GND switch also becomes also be reduced. The proposed method is able to perform load-adaptive operation by controlling the voltage level of energy recovery capacitor, which prevents increasing inefficient power consumption caused by circuit loss during recovery operation. Test results with 50' HD single-scan PDP(resolution = 1366$\times$768) show that less than 3sons of recovery time is successfully accomplished and about$54\%$ of the maximum power consumption can be reduced, tracing minimum power consumption curves.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.8
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• pp.500-508
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• 2004

This paper presents a new sensorless vector control system for high performance induction motor drives fed by a matrix converter with non-linearity compensation and disturbance observer. The nonlinear voltage distortion that is caused by commutation delay and on-state voltage drop in switching device is corrected by a new matrix converter modeling. The lumped disturbances such as parameter variation and load disturbance of the system are estimated by the radial basis function network (RBFN). An adaptive observer is also employed to bring better responses at the low speed operation. Experimental results are shown to illustrate the performance of the proposed system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.11
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• pp.888-895
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• 1989

A novel model reference adaptive control (MRAC) scheme for electrical servo drives is proposed, in which the control input is synthesized without any parameter identification mechanism and a PI controller is inserted ahead of the plant to reduce the steady state chattering. The proposed scheme is shown to be asymptotically stable in the case where the load torque disturbance satisfies a certan condition. An application to a permanent magnet synchronous motor drive shows that the output error between the plant and the reference model tends to zero and the chattering is greatly reduced.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.13-15
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• 2007

The washing machine needs high torque for large load variation, Interior permanent magnet synchronous motor(IPMSM) is proper to adapt the washing machine system. However, IPMSM can operate the lower output power than the other permanent magnet synchronous motor(PMSM) when the motor control by the conventional control. This paper suggests adaptive motor control for IPMSM and experiments the washing machine system.

• Annual Conference of KIPS
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• 2002.11a
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• pp.183-186
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• 2002

클러스터는 부하 분산 스케줄링의 방법에 따라서 그 시스템의 성능이 달라진다. 본 논문에서는 클러스터의 한 종류인 LVS에서 제시되었던 RR, WRR, LC, WLC의 부하 분산 스케줄링을 이용하여 시스템의 각종 부하를 처리하는 방법과 클러스터의 각 서버의 성능을 측정하여 부하 분산을 결정하는 ALBM(Adaptive Load Balancing Mechanism) 방식을 비교하였다. 이 성능 평가를 하기 위하여 여러 실험 환경 설정을 하여 다양한 실험을 통하여 비교 분석 하였다. 실험을 통하여 ALMB 이 기존의 여러 스케줄링 방식에 비하여 전체적으로 좋은 성능 결과를 낳았으며 클러스터 서버간의 안정적인 부하 분산이 되는 결과를 얻었다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06b
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• pp.228-231
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• 2007

ALBM(Adaptive Load Balancing and Management)은 S/W L4 스위치를 포함하는 능동형 클러스터 시스템이다. 이 클러스터 시스템은 확장 가능한 인터넷 서비스와 적응형 부하분산 처리 능력을 제공한다. ALBM 클러스터 시스템을 설계할 때, 우리는 Model-Driven Development Method를 사용하여 메타모델을 설계하였다. 본 논문에서는 클러스터의 구성을 위한 에이전트관리, 정보관리와 같은 기능과 결함내성을 위한 이벤트관리, 알고리즘관리와 같은 기능을 고려하는 메타모델을 제시한다. 이 메타모델의 초점은 클러스터의 구성관리와 결함관리를 클러스터 관리 시스템의 설계에 반영하여, 새롭게 클러스터 시스템을 설계할 때 쉽게 이러한 기능을 가질 수 있도록 지원하는 것이다.

• ETRI Journal
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• v.41 no.1
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• pp.124-132
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• 2019

The energy balance (EB) model of a primary side regulation (PSR) fly-back converter in the discontinuous conduction mode (DCM) is discussed in this paper. Based on this EB model, the stability of a PSR fly-back converter in the pulse skipping mode (PSM) is analyzed, and a self-adapting modulation factor control strategy is proposed. Theoretical analysis and simulation results show that by saving an optocoupler and correlative circuits, which are necessary in traditional PSM fly-back converters, the modulation factor tolerance controlled by this method is 1.26% on average, corresponding to the ideal value. Compared with traditional fly-back PSM controllers, the power saved in the sampler/comparator modules is 87% on average for a load range of $1{\Omega}$ to $1k{\Omega}$.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5669-5684
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• 2018

The new mobile edge network architecture has been required for an increasing amount of traffic, quality requirements, advanced driver assistance system for autonomous driving and new cloud computing demands on highway. This article proposes a hierarchical cloud computing architecture to enhance performance by using adaptive data load distribution for buses that play the role of edge computing server. A vehicular dynamic cloud is based on wireless architecture including Wireless Local Area Network and Long Term Evolution Advanced communication is used for data transmission between moving buses and cars. The main advantages of the proposed architecture include both a reduction of data loading for top layer cloud server and effective data distribution on traffic jam highway where moving vehicles require video on demand (VOD) services from server. Through the description of real environment based on NS-2 network simulation, we conducted experiments to validate the proposed new architecture. Moreover, we show the feasibility and effectiveness for the connected car media service on highway.