• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.5
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• pp.467-477
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• 2004

A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The typical speed estimation scheme in most servo system for low speed operation is sensitive to the variation of machine parameters, especially the moment of inertia. To estimate the motor inertia value, the observer using the Radial Basis Function Networks(RBFN) is applied. The effectiveness of the proposed inertia estimation method is verified by experiments. It is concluded that the speed control performance in the low speed region is improved with the proposed disturbance observer using RBFN.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.6
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• pp.554-560
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• 1999

In this paper, a vibration suppression method using an energy stored in winding inductance and an induced v voltage of the Linear Stepping Motor(LSM) is shown, and it is applied to a new one-phase excitation method A And a magnetic equivalent circuit is based on the structure of the LSM, and then the electric equivalent circuit of the LSM is derived by solving equations for the magnetic equivalent circuit. Several dynamic characteristics of the LSM are analyzed by the ACSL with the voltage equations, the force equations and the kinetic equation, a and are measured by experimental system.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.555-558
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• 2003

When a fault relating to the urgent alarm occurs, we must prevent control rods from dropping and make one of two grippers in Control Rod Drive Mechanism (CRDM) grip the drive rod laking a control rod assembly. If a gripper with any problem is ordered to grip the drive rod, the gripper which cannot latch the rod stably will fail to take the rod. On the purpose of escaping this bad case, we order two grippers to hold the drive rod and enhance the reliability of holding control rods. This action is called the double hold. In the middle of the movement of the drive rod, the latching of the drive rod can cause friction between a gripper and the drive rod. This state may give damage to both the gripper and the drive rod. In this paper, we have devised the method which can have two grippers hold the drive rod more stably, without damaging the equipment.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.559-562
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• 2003

In this paper, we introduce a new method detecting thyristor faults of the power converter module in Control Rod Control System. When we control the currents in each coil of Control Rod Drive Mechanism by using the current control method, the current value can follow the current reference despite the faults like the missing phase or the diode acting. Comparing the fault current values with the normal current values, the bad transient characteristics of the abnormal current can make the operations of control rods incorrect. In this case, the information from the current trends cannot be enough to detect the fault occurrence in thyristors. Instead of the coil currents, the state of thyristors can be watched by measuring the coil voltages. In the existing system of Westinghouse type, the ripple detector takes charge of this task. But this detector has some shortcomings in the point of time for fault detection, we come to devise a new fault detection method solving the problems which belong to the ripple detector.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.563-566
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• 2003

We have designed the power control unit which belongs to the power cabinet and controls the power supplied to Control Rod Drive Mechanism(CRDM) as a digital system based on Digital Signal Processor(DSP). The power control unit dualized as the form of Master/Slave has had its increased reality. The Central Process Unit(CPU) board of a power control unit possesses two Digital Signal Processors(DSPs) of the control DSP for performing the tasks of power control and system monitoring and the communication of the Control DSP and the Communication DSP. To accomplish the functions requested in the power control unit effectively, we have installed Field Programmable Gate Arrays(FPGAS) on the CPU board and have FPGAs perform the memory mapping, the generation of each chip selection signal, the giving and receiving of the signals between the power controllers dualized, the fault detection and the generation of the firing signals.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.9
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• pp.739-744
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• 2016

The truck that is used as running equipment for tank freight car support is a core structural part that supports the load of the car body and significantly influences the safety of freights and vehicles, as well as their running performance. Running equipment is composed of truck frames, wheels and wheel axles, independent suspensions, and brakes. Among these components, the truck frame supporting the load of the vehicles and freights may be the most important component. This study was carried out to analyze the structure of truck frames and to determine whether they are safe when the maximum vertical load, braking part load, and the front and rear load are applied to truck frames. This was achieved by subjecting the truck frames to stress tests and then measuring the stress on each part. The results of the stress tests showed that truck frames have a safe vehicle load design.

• Journal of Biomedical Engineering Research
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• v.14 no.2
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• pp.163-167
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• 1993

We developed a ventricular assist device(VAD) to be used as a bridge to heart transplantation or a circulatory assist device for patients with end-stage heart disease or poor myocardial function after cardiac surgery. It is a pneumatic and diaphragm-type VAD and its stroke volume is 90 cc. The upper housing and diaphragm is made of a segmented polyurethane and the lower back plate is made of a polycarbonate. Two Carbomedics$^R$ mechanical valves are used as inlet and outlet valves. It was tested in vitro and the cardiac output of the VAD was 7 L/min at a heart rate of 70 bpm. The line pressure from a pressure transducer inserted in the pneumatic line was recorded and compared with the ideal pressure tracing.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.703-705
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• 2002

본 논문에서는 홈 자동화 네트워크의 대표적으로 자리잡고 있는 론웍스(Lonworks) 시스템의 하드웨어 플랫폼인 뉴론칩(Neuron) 기반의 노드를 대신하는 새로운 구조를 갖는 홈 자동화 제어기를 제안한다. 기존의 론웍스 해답(Solution)은 8비트 프로세서인 뉴론칩을 모든 노드들이 중앙처리장치로 사용하므로 고성능의 처리를 필요로 하는 응용 프로그램은 구현할 수 없었다. 또한 뉴런C(Neuron C) 언어를 사용하여 응용 프로그램을 개발하므로 C 언어에서 파생된 언어인 뉴런C 언어를 새롭게 배워야 하는 번거로운 점을 가지고 있으며, 뉴런C 컴파일러(Compiler)를 비롯한 LonMaker 등의 고가의 개발 장비를 구비해야 하므로 개발자로 하여금 개발비용에 대한 부담이 컸다. 이에 본 논문에서는 처리능력이 뛰어나며 저전력 특성을 갖춘 스트롱암(SA1110)칩을 메인 프로세서로 사용한 홈 자동화 제어기인 ECONICS를 개발했다. 이 ECONICS는 홈 제어 네트워크를 구성하기 위해 통신 하드웨어 및 ANSI 표준 프로토콜인 EIA709.1 통신 프로토콜 스택을 가지고 있다. 제안된 홈 자동화 제어기를 통하여 기존의 론웍스 노드에서 구현하기 힘든 다양하고 복잡한 응용프로그램을 구현할 수 있게 되었고, 제안된 홈 자동화 제어기의 상업적 유용성을 증명하기 위해 기존의 론웍스 노드들과의 호환성을 확인하였으며 개발자로 하여금 기존의 C 언어를 통하여 응용프로그램을 개발하게 함으로써 추후 홈 자동화 제어기로써 파급효과가 클 것이다.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.3
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• pp.380-387
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• 2010

For the fault diagnosis of three-phase induction motors, we propose a diagnosis algorithm based on mutual information and linear discriminant analysis (LDA). The experimental unit consists of machinery module for induction motor drive and data acquisition module to obtain the fault signal. As the first step for diagnosis procedure, DFT is performed to transform the acquired current signal into frequency domain. And then, frequency components are selected according to discriminate order calculated by mutual information As the next step, feature extraction is performed by LDA, and then diagnosis is evaluated by k-NN classifier. The results to verify the usability of the proposed algorithm showed better performance than various conventional methods.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.12
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• pp.2298-2305
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• 2007

Many people is studying the embedded system. The embedded system becomes a small size device. The DOM memory is using in the mobile device and small site devices. This paper proposes light-weighted Linux O.S that is running onto the DOM memory. The embedded system with the DOM must have a light-weigthed O.S due to the memory space restriction. This paper designs light-weigthed Linux O.S for the DOM memory. The new designed LILO boot loader boots the new designed light-weigthed Linux O.S as a normal Linux O.S. This paper experiments comparing the designed new light-weigthed Linux O.S with a Linux PC.