• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.530-533
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• 1993

This paper describes a new method of dynamic error compensation, using a digital convolution integrator and two digital low pass filters. In this method, the process of compensation consists of three steps. First, sampling and digitizing of input signal, second, removing the noise in sampled data by the low pass filter and third, making a convolution integral using the output data of low pass filters. This method showed a good experimental result of reducing dynamic error even if there was a slight noise in the input signal. As a result, the detecting time constant of resistance thermo-bulb was improved to about 1/10th.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1191-1192
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• 2011

We released new triple redundant digital excitation system with real time generator-turbine simulator. One of its great merits is the real time generator-turbine simulator when it was compared with the other products. If excitation system is tripped by unexpected faults, Maintenance man can do easily performance test of digital excitation control board, sequence relay and thyristor switching device of phase controlled rectifier without manufacturer's support. For the verification of this system, It was tested with an actual excitation system implemented on 5kVA M-G Set. After finishing the tests, the trial product will be installed and operated at a 500MW thermal power plant.

• 전기학회논문지
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• 제56권4호
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• pp.677-682
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• 2007

In the distribution system, Change of system happens frequently. However, most of the relays are operated manually by a person or not changed when system changed. So, when fault happened, a case that relaydoes not act rapidly happens. Also, in current power system, digital relays are used because of digitization of relay. Digital relay has very many advantages than existing analog relay. One of these advantages is that communication is available and easily can make characteristic curve. If specific values are sent to a relay by communication, A relay can make suitable characteristic curve according to the value. In this paper, by using voltages and currents measured by relay, state of CB(Circuit Breaker) and these relays, SCADA(Supervisory Control And Data Acquisition) system that control and correct characteristic curve of overcurrent relay at system change by using HMI(Human Machine Interface) is proposed.

• 한국인쇄학회지
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• 제16권3호
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• pp.81-95
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• 1998

If a image doesn't include sufficient data of output size and resolution, we will scan again the image. Interpolation generates a new pixel by methematical average of processing. In the interpolation method, there are nearest neighbor interpolation, bilinear interpolation and bicubic interpolation etc. This study was carried out for the purpose of researching compatible method to digital scan image caused by only different interpolation methods. Nearest neighbor interpolation show superior effect in the drawing image. Bilinear interpolation show reduction in detail and contrast. Bicubic interpolation show superior effect in the digital photo image USM(Unsharp Mask) application after extension by interpolation show better than extension by interpolation after USM(unsharp mask) application.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.81-83
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• 2005

The Reactor Protection System (RPS) is a very important system in a nuclear power plant because the system shuts down the reactor to maintain the reactor core integrity and the reactor coolant system pressure boundary if the plant conditions approach the specified safety limits. This paper describes the unavailability assessment of a digital reactor protection system using the fault tree analysis technique. The fault tree technique can be expressed in terms of combinations of the basic event failures. In this paper, a prediction method of the hardware failure rate is suggested for a digital reactor protection system. and applied to the reactor protection system being developed in Korea.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집(한일합동학술편); 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.753-758
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• 1987

The purpose of ocean thermal energy conversion (OTEC) plant control is to provide stable power efficiently by appropriately regulating the seawater flow rates and the working fluid flow rate under conditions of continually changing seawater temperatures. This paper describes digital control of working fluid flow rate based on an adaptive control theory for the "Imari 2" OTEC plant at Saga University. Provisions have been made for linkage between the software of the adaptive control theory and the hardware of the OTEC plant. In implementing the working fluid flow rate control, if persistency of excitation conditions are lost, the algorithm of identification often exhibits bursting phenomena. To avoid this difficulty, the stopping-and-starting rule for identification was derived and was used for the working fluid flow rate control. Satisfactory control performance was then obtained by using this digital control system.ol system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.113.3-113
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• 2001

In this paper, we have designed the VHDL module of DS/SS QPSK wireless modem processor for digital data communication. The spread spectrum method is used for modern processor, because this method guarantees good frequency efficiency and higher security. Also, it guarantees good performance in digital communication system under multi-path interferences. The differential encoder and decoder are used for simple circuit composition in the signal detection. For the synchronization of receiver, matched filter and power detector are used. And the IF modulation/demodulation of QPSK method is used in the digital level. The transmitter of VHDL modem processor consists of differential encoder, PN code generator, and QPSK ...

• 인터넷정보학회논문지
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• 제3권6호
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• pp.35-41
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• 2002

차량항법 시스템에서는 디지털 맵을 대상으로 하기 때문에 많은 양의 메모리가 소요되며 계산시간도 많이 필요하게 된다. 또한 교통 상황은 실시간으로 변하기 때문에 이러한 정보를 차량항법 시스템에 반영한다면 좀더 실제적인 결과를 얻을 수 있을 것이다. 본 연구에서는 출발지와 목적지간의 방향정보를 이용하여 차량운행 중에 발생하는 실시간 교통정보를 반영하면서도 적은 계산시간과 메모리 사용으로도 효율적인 경로 탐색을 할 수 있는 알고리즘을 제안하였다.

• Journal of electromagnetic engineering and science
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• 제1권2호
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• pp.131-138
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• 2001

The DTV (Digital TV) tuner for an 8-VSB (Vestigial Side-Band) modulation was developed to meet the requirements of the ATSC (Advanced Television Systems Committee). The double frequency conversion and the active tracking filter in the front-end were used to cancel interferences between adjacent channels and multi-channels by suppressing the IF beat and the Image frequency. However, It was impossible to get frequency mapping between the tracking filter and the first VCO (Voltage Controlled Oscillator) in the existing DTV tuner structure which differs from the NTSC (National Television Systems Committee) tuner. This paper, therefore, suggests an assailable structure and a new method for the automatic frequency selection by mapping the frequency characteristics over the tracking voltage and the combined HW which is composed of a Micro-controller, an EEPROM (Electrically Erasable Programmable Read Only Memory), a DAC (Digital-to-Analog Converter), an OP amplifier, and a switch driver.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 추계학술발표회 논문집
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• pp.319-324
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• 2004

With a PMS, a maintenance plan should be drawn up after surface conditions are precisely examined and analyzed. The majority of the present PMSs are run by the fact that experts first examine surface conditions on sites, and then enter results into systems. However, considering the actual circumstances of the present time and an increase in paved road hereafter, it is inefficient that experts examine the whole paved roads in person and long-lasting PMSs can not be kept up. Therefore, in the study digital photogrammetry was used to examine asphalt concrete pavements. In a consequence, it was found that if databases are implemented in the future with quality digital image information accumulated from studies on roads, they will be able to provide the field of pavement management system with a large amount of information and data.