• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.1
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• pp.1-8
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• 2002

It has been integrated into several navigation systems. This paper shows that system recognizes difficult indoor roads without any specific marks such as painted guide line or tape. In this method the robot navigates with visual sensors, which uses visual information to navigate itself along the read. The Neural Network System was used to learn driving pattern and decide where to move. In this paper, I will present a vision-based process for AMR(Autonomous Mobile Robot) that is able to navigate on the indoor read with simple computation. We used a single USB-type web camera to construct smaller and cheaper navigation system instead of expensive CCD camera.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.163-166
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• 2004

The conventional fluorescent lamp dimming system using an another control line is complex and will increased the cost. Therefore, many studies have focused on the wireless communication, but it is not fit for dimming system because of the interference generated by the infra-red light of lamp or switching noises in ballast. So, we applied the power line communication on the dimming system and we proposed a new coupling circuit using the voltage controlled impedance convertor for improving the performance of the FH/SS PLC modem. The performance for the proposed modem is evaluted by the BER.

• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.354-362
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• 2008

In this paper, a new algorithm of optimal voltage control is proposed for the Distribution Automation System (DAS) based on constants of four terminal network modeling. In the proposed method, the voltage profiles along feeders are estimated from the measurement of the current and power factor by a Feeder Remote Terminal Unit (FRTU) installed at each node. Whenever the voltage profile violates the restriction, the voltage control strategy is applied to keep the voltage levels along the feeders within the pre-specified range through the modification and coordination of the transformer under-load tap changers (ULTC), step voltage regulator (SVR), as well as shunt condenser. In the case studies, the estimation and control of the voltages have been testified in a radial distribution system with 11 nodes.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.252-255
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• 2003

Digital environment that is represented to internet is displacing business way of industry and business achievement way with the fast speed being giving great change on life whole, improve existence business process utilizing internet and Web connection technology, information superhighway to tradition industrialist manufacture and e-transformation's propulsion that wish to maximize productivity and administration efficiency is spread vigorously. In this paper, we wish to accomplish generation equipment's heighten stability and believability through remote monitoring and control of BIPV system. This paper describes the design of the monitoring system for sensing the monitoring data and indirect controlling of the BIPV system. Most of the conventional monitoring system depend on the special hardware and software. Basic design goal of monitoring system is to provide the convenience for the user and the portability for the system. In order for the system to fulfill its requirements, it was designed using Labview GUI facility based on the Windows 2000 environment of IBM PC compatible and Add-on card based on the TCP/IP protocol. Advantage of the monitoring system are a personnel expenses curtailment effect, free of the place restriction and unmanned system of the generation plants, etc.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.387-394
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• 2013

A travel aid system for the visually impaired person is proposed by providing the position and heading information. The position and heading information is obtained from range difference localization estimator, and the information is notified to the visually impaired person by using braille display system. For the precise estimation of the position and heading information, we apply recently developed linear localization estimator which utilizes the instrumental variable method and the state augmentation method. The estimation results are compared with well-known Kalman filter through experiment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1354-1363
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• 2014

In this paper, an improved method of fault indicator generation algorithm in FRTUs is proposed for the present Distribution Automation System. In order to find fault area, correct FI information should be generated. But when a single line-to-ground fault occurs, FI information is generated in downside of the fault in some circumstance because existing FI algorithm considers only magnitude. It is found that the upside fault current direction if different from the downside fault current direction. Therefore, in order to prevent to generate the wrong fault indication information for FRTU at the downside of the fault, an improved fault indication generation method is developed. Not only the basic conditions are taken into account, but also the directions from the angle difference between zero and positive sequence currents are considered to generated the fault indication information. In case study, the proposed method has been testified and shown the reasonability in generating correct the fault indication information, for many kinds of faults according to conditions.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.673-676
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• 2001

The photovoltaic power generation system has a great future as clean energy instead of fossil fuel, which has many environmental problems such as exhausted gas or air pollution. In a utility interactive photovoltaic generation system, a three phase inverter is used for the connection between the photovoltaic array and the utility. This paper presents a three phase inverter for photovoltaic power system with current controller, voltage controller, PLL control system and the phase detector of interactive voltage by using dq transformation. The proposed inverter system provides a sinusoidal ac current for domestic loads and the utility line with unity power factor.

• Journal of Electrical Engineering and Technology
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• v.10 no.2
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• pp.474-486
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• 2015

This paper proposes a multi-objective optimal placement method of Phasor Measurement Units (PMUs) in large electric transmission systems. It is proposed for minimizing the number of PMUs for complete system observability and maximizing measurement redundancy of the buses, simultaneously. The measurement redundancy of the bus indicates that number of times a bus is able to monitor more than once by PMUs set. A high level of measurement redundancy can maximize the system observability and it is required for a reliable power system state estimation. Therefore, simultaneous optimizations of the two conflicting objectives are performed using a binary coded firefly algorithm. The complete observability of the power system is first prepared and then, single line loss contingency condition is added to the main model. The practical measurement limitation of PMUs is also considered. The efficiency of the proposed method is validated on IEEE 14, 30, 57 and 118 bus test systems and a real and large- scale Polish 2383 bus system. The valuable approach of firefly algorithm is demonstrated in finding the optimal number of PMUs and their locations by comparing its performance with earlier works.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2852-2858
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• 2022

A proton therapy facility is under development at Huazhong University of Science and Technology (HUST). To meet the need for fast energy changes during treatments, a beamline control system (BCS) has been designed and implemented. The BCS coordinates and controls various beamline devices by adopting a distributed architecture divided into three layers: the client, server, and device layers. Among these, the design of the server layer is the key to realize fast energy changes. The server layer adopts the submodule programming paradigm and optimizes the data interface among modules, allowing the main workflow to be separated from the device workflow and data. Furthermore, this layer uses asynchronous, multithreaded, and thread-locking methods to improve the system's ability to operation efficiently and securely. Notably, to evaluate the changing energy status over time, a dynamic node update method is adopted, which can dynamically adjust the update frequency of variable nodes. This method not only meets the demand for fast updates on energy changes but also reduces the server's communication load in the steady state. This method is tested on a virtual platform, and the results are as expected.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.619-620
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• 2006

차세대 무선통신 'ZigBee' 는 표준인준으로 상용화가 임박하였으며, 저전력을 장점으로 홈 네트워크에 가장 적합한 것으로 평가되고 있다. 그래서 우리는 이러한 ZigBee 통신과 현재 가장 보편화 되어있는 휴대용 단말기인 휴대폰을 이용하여 원거리에서 가정을 감시 및 제어 할 수 있는 시스템을 구축하였다.