• International Journal of Aeronautical and Space Sciences
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• v.16 no.1
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• pp.102-109
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• 2015

In Korea, Lunar exploration program has been prepared with the aim of launching in the 2020's. As a part of it, a lunar lander demonstrator was developed, which was the model for verifying the system such as structure, propulsion, and control system, before launching into the deep space. This paper deals with the path tracking performance of the lunar lander demonstrator with respect to the thruster controller based on Pulse Width Pulse Frequency Modulator (PWPFM) and Pulse Width Modulator (PWM). First, we derived equations of motion, considering the allocation of the thrusters, and designed the path tracking controller based on Euler angle. The signal generated from the path tracking controller is continuous, so PWPFM and PWM modulator are adopted for generating ON/OFF signal. Finally, MATLAB simulation is performed for evaluating the path tracking ability. We compared the path tracking performances of PWPFM and PWM based thrust controller, using performance measures such as the total impulse and the position error with respect to the desired path.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.112-115
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• 2001

Eigenvalue perturbation theory of augmented system matrix(AMEP) is a useful tool in the analysis and design of large scale power systems. This paper describes the application results of AMEP algorithm with respect to all controller parameter of KEPCO systems. AMEP for interarea and local mode can be used for turning controller parameter, and verifying system data and linear model of controller.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.349-351
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• 2003

A real time simulation method for the stand-alone Wind Power Generation System (WPGS) based on the real-time digital simulator (RTDS) is proposed in this paper for the simulations under the real weather conditions. The wind turbine characteristic equation of a wind turbine is reconstructed in the RTDS, and then the real data of weather conditions are interfaced to the RTDS through the analogue input Ports of the RTDS. The outcomes of the simulation demonstrate the effectiveness of the proposed simulation scheme in this paper. The results show that the cost effective verifying for the efficiency and stability of the WPGS.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1241-1246
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• 2004

The verification confirms a correspondence between requirements and a specification before implementing. The problem in the formal method verifying a protocol specification using model checking is that the protocol behaviors must be always specified in L TS(Label Transition System). But if Region Automata is applied to the model checking, it is enable to verify whether properties are true on specification specified in I/O FSM(Input/Output Finite State Machine) as well as LTS. In this paper, we verify the correctness of rail signal control protocol type 1 specified in I/O FSM by using model checking method and region automata. This removes many errors and ambiguities of an informal method used in the past and saves down expenditures and times required in the protocol development. Therefore it is expected that there will be an increase in safety, reliability and efficiency in terms of the maintenance of the signaling system by using the proposed verification methods.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2811-2813
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• 2000

Nowadays PLC is used for controlling various industrial processes. For its better performance operating status of PLC should be continuously checked. However. it is difficult to monitor the status of PLC owing to the spatial limitation. This paper presents an internet based remote monitoring and control system for PLC and a practical implementation for Tiny PLC is executed for verifying its feasibility.

• Structural Engineering and Mechanics
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• v.19 no.6
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• pp.721-747
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• 2005

The strong need of verifying theories formulated for semi-active control through applications to real structures is due to the fact that theoretical research on semi-active control systems is not matched by a corresponding satisfactory experimental activity. This paper shows how a smart system including magnetorheological devices as damping elements can be implemented in a large-scale structural model, by describing in detail the kind of electronics (dedicated hardware and software) adopted during the experimental campaign. It also describes the most interesting results in terms of reduction of the seismic response (either experimental or numerical) of the semi-actively controlled structure compared to a passive operating control system, and in terms of the evaluation criteria proposed in the benchmark for seismically excited controlled buildings. The paper also explains how to derive from the classical theory of optimal control the adopted control logic, based on a clear physical approach, and provides an exhaustive picture of the time delays characterizing the control sequence.

• Journal of Integrative Natural Science
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• v.9 no.3
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• pp.199-205
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• 2016

In this paper, we established ZIGBEE home network and combined smart-grid and u-Healthcare system. We assisted for amount of electricity management of household by interlocking home devices of wireless sensor, PLC modem, DCU and realized smart grid and u-Healthcare at the same time by verifying body heat, pulse, blood pressure change and proceeded living body signal by using SVM algorithm and variety of ZIGBEE network channel and enabled it to check real-time through IHD which is developed by user interface. In addition, we minimized the rate of energy consumption of each sensor node when living body signal is processed and realized Query Processor which is able to optimize accuracy and speed of query. We were able to check the result that is accuracy of classification 0.848 which is less accounting for average 17.9% of storage more than the real input data by using Mjoin, multiple query process and SVM algorithm.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.10
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• pp.59-68
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• 1992

In this paper, we proposed coordinator description and ambiguity on the hybrid controller for position/force control of robot manipulator. When the hybrid controller is desiged based on the PID control conception, the parameter sharing problem must be considered. However, selection problem of coordinate system on n-DOF robot manipulator control is unsolved. Moreover, contact force on object and change of shape make another problems. And it is very difficult to figure out the accurate mathematical model of manipulator on account of ambiguity and nonlinearity of actuator. Therfore, we design a new hybrid controller, FPID(Fuzzy PID). For verifying the validity of the controller, we tried computer simulation of this system. As a result, we can get remarkable improvement of overdamping and overshooting. Also we can solve compicance problem effectively. Furthermore, ambiguity problem is solved by adding control knowledge based compensator. So robust controller can be acheived, too.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.113-116
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• 1998

A numerical study was performed on the fluid flow in the melt of the cold model for Czochralski growth system. The fluid flow in the melt of Woods metal with crucible diameter of 20cm was calculated using a three dimensional finite difference method. Since the crucible size is large, fully turbulent model as well as laminar model was used in the calculation. The effects of crucible rotation rate, crystal rotation rate and wall temperature difference on the velocity and temperature distribution were also investigated. For the purpose of verifying the results of calculation, a cold model experiment using Woods metal was also conducted and the velocity distribution in the melt of the model was measured.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.3
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• pp.51-62
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• 2013

We propose a method using QFD for design the hierarchical structure of AHP. This method provides definition for each area of House of Quality and design the hierarchical structure of the bottom-up QFD/AHP in which the upper hierarchy is designed through the classification of common characteristics with a focus on the lower hierarchy. Finally, we apply it to the development of an evaluation index for selecting heavy lifting service providers. This study has significance as the first instance of designing the archical structure of AHP after objectively verifying whether MECE condition, the basic requirement for AHP design, is satisfied.