• Journal of Power Electronics
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• v.12 no.6
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• pp.982-991
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• 2012

In this study, a new method has been presented for the detection of broken rotor bar (BRB) faults in inverter driven induction motors controlled via Field Oriented Control (FOC). To this end, a FOC controlled induction motor with a BRB fault was modeled using the Matlab/Simulink program. Experiments were carried out using the prepared simulation model at various loads and operating speeds. The motor current and speeds were monitored for healthy, 1, 2 and 3 BRB faults. The Resampling Based Order Tracking Analysis (RB-OTA) method was applied to the monitored signals. The obtained results were compared by using the classic Fast Fourier Transform (FFT) method. When the obtained results were analyzed via the FFT method no information regarding any faults was determined in the run up or run down regions of the motor and the presented method gave very good results. The reliability of the proposed method was validated with experimental results. The main innovative part of this study is that the RB-OTA method was implemented on the induction motor current signal for detecting BRB faults.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.436-438
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• 2005

모델 기반 아키텍처 (Model Driven Architecture, MDA)는 플랫폼 독립적인 모델로부터 변환 규칙을 이용하여 특정 플랫폼 용 모델을 생성하는 소프트웨어 자동화 기술로 각광을 받고 있다. EJB(Enterprise JavaBeans)는 컴포넌트 기반의 분산 컴퓨팅을 위한 아키텍처로써 Java 기반 어플리케이션 개발에서 가장 널리 사용되는 개발 플랫폼이다. 기존의 PIM에서 EJB 용 PSM으로 변환 규칙에 대한 연구는 아직 미흡하고 체계적이지 못하다. 본 논문에서는 PIM 의 구조적인 구성요소와 EJB 용 PSM 의 구성요소를 비교 분석하여 변환 규칙을 정의한다. EJB 어플리케이션 개발을 위해 제안된 변환 규칙을 적용한다면 모델간의 대응관계를 효율적으로 표현 할 수 있기 때문에 이들간의 일관성과 추적성을 높일 수 있고 제품의 생산성, 유지보수성을 높일 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.325-327
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• 2005

컴포넌트는 컴포넌트 기반 개발(Component Based Development, CBD)기술에서 재사용되는 기본 단위로서 OOP(Object Oriented Programming, OOP)의 객체보다 상대적으로 큰 단위의 기능성을 제공하며 재사용성이 뛰어나다. 모델 기반 아키텍처(Model Driven Architecture, MDA)는 모델들 간의 다양한 변환(Transformation)을 활용하여 어플리케이션 개발을 자동화하는 새로운 패러다임으로서 소프트웨어의 생산성을 향상시킨다. 그러나 MDA 는 컴포넌트와 같은 어플리케이션들 간의 공통성과 가변성을 활용한 재사용성을 직접적으로 지원하지는 않는다. 본 논문에서는 CBD 와 MDA 의 장점과 한계점을 알아보고 서로의 단점을 보완할 수 있도록 컴포넌트 PIM 과 컴포넌트 기반의 MDA 공학 프로세스를 제안한다. 제안된 컴포넌트 PIM 과 프로세스를 이용하면 어플리케이션들 간의 공통성과 가변성을 이용한 뛰어난 재사용성과 자동화를 통한 생산성의 ,향상 및 높은 유지보수성을 가질 수 있다.

• Electrical & Electronic Materials
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• v.9 no.1
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• pp.24-29
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• 1996

A composite piezoelectric ceramic transducer is fabricated with three piezoelectric ceramic disk vibrators and two sheets of thin insulator. Its equivalent circuit is derived from the Mason's model of a thickness-driven piezoelectric vibrator. When the electric input near its fundamental resonance frequency is applied to the center vibrator and the output voltages across the left and the right vibrators are connected in series to the resistor loads, the load characteristics at resonance frequencies under the various resistor loads and the frequency characteristics near the resonance frequency without load are investigated. Furthermore, symbolic expressions for input impedances, voltage ratios, resonance frequencies, and bandwidths are derived. The data calculated from those symbolic expressions are agreed well with the measurement data.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.977-979
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• 1996

This paper presents an algorithm to control the undesirable sway of a suspended load in the crane system that has a trade-off between positioning the load and suppressing the sway of the load. The aim is to transport the load to a specified place with small sway angle as quickly as possible. Dynamic model is based on a simple pendulum driven by a velocity drive that is mostly used for actuating a trolley in industry. Proposed algorithm is composed of two parts : one is a off-line optimal trajectory generator, the other on-line tracking control. The former produces optimal trajectories minimizing energy under the speed constraint of velocity drive. The latter controls outputs to track the generated trajectories. Digital simulations and experiments are performed on a pilot crane to demonstrate the performance of the proposed control algorithm.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1048-1050
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• 2003

Recently, many linear motion generators and motors are rapidly finding applications that ranges from short stroke linear motion vibrators, such as dynamic con type loud speakers to stilting engine driven linear reciprocating alternators, compressors, textile machines etc. In this paper, we analyze the characteristics of tubular linear motor with Halbach and radial magnet array respectively. We already derived magnetic field solutions due to the PMs and to the currents and Motor thrust. On the basis of analytical field solutions, this paper deals with flux linkages and back emf. The results are validated extensively by comparison with finite element analyses. Then, this parer also presents thrust characteristics according to design parameters for each model.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1151-1153
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• 2003

In this paper, switching surge voltage distribution in stator windings of induction motor driven by IGBT PWM inverter is studied. To analyze the irregular voltage of stator winding, equivalent circuit model of inverter-cable-motor was proposed and high frequency parameter is computed by using finite element method (FEM). Electromagnetic transient program (EMTP) analysis of the whole system for induction motor and PWM inverter is proposed. In order to experiment, an induction motor, 380 [V], 50 [HP], with taps from one phase and a switching surge generator was built to consider the voltage distribution.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1036-1038
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• 2003

Electric control of eddy coupling offers many new possibilities in process control and other industrial control applications. And a form of speed control for the load is affected for a system driven by costant frequency induction motor. This paper compare speed-torque characteristic of three types of eddy-current coupling by using the analytical method. And characteristic experiment of three types of eddy current coupling is put into operation. And then, this paper will discuss operational and magnetic field characteristic of three types model.

• Environmental Engineering Research
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• v.10 no.2
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• pp.88-103
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• 2005

In this paper, data-driven modeling and multiresolution analysis (MRA) are applied for a full-scale wastewater treatment plant (WWTP). The proposed method is based on modeling by partial least squares (PLS) and multiscale monitoring by a generic dissimilarity measure (GDM), which is suitable for nonstationary and non-normal process monitoring such as a biological process. Case study in an industrial plant showed that the PLS model could give good modeling performance and analyze the dynamics of a complex plant and MRA was useful to detect and isolate various faults due to its multiscale nature. The proposed method enables us to show the underlying phenomena as well as to filter out unwanted and disturbing phenomena.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.111-118
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• 1999

Recently computer can make cyberspace to walk through by an interactive virtual reality technique. An a avatar in cyberspace can bring us a virtual face-to-face communication environment. In this paper, an avatar is realized which has a real face in cyberspace and a multiuser communication system is constructed by voice transmitted through network. Voice from microphone is transmitted and analyzed, then mouth shape and facial expression of avatar are synchronously estimated and synthesized on real time. And also an entertainment application of a real-time voice driven synthetic face is introduced and this is an example of interactive movie. Finally, face motion capture system using physics based face model is introduced.