• 제어로봇시스템학회논문지
• /
• 제9권1호
• /
• pp.57-62
• /
• 2003

It is difficult to determine the feeding rate of coagulant in the water treatment plant, due to nonlinearity, multivariables and slow response characteristics etc. To deal with this difficulty, the genetic-fuzzy system genetic-equation system and the neural network system were used in determining the feeding rate of the coagulant. Fuzzy system and neural network system are excellently robust in multivariables and nonlinear problems. but fuzzy system is difficult to construct the fuzzy parameter such as the rule table and the membership function. Therefore we made the genetic-fuzzy system by the fusion of genetic algorithms and fuzzy system, and also made the feeding rate equation by genetic algorithms. To train fuzzy system, equation parameter and neural network system, the actual operation data of the water treatment plant was used. We determined optimized feeding rates of coagulant by the fuzzy system, the equation and the neural network and also compared them with the feeding rates of the actual operation data.

• 제어로봇시스템학회논문지
• /
• 제3권6호
• /
• pp.652-658
• /
• 1997

Coagulant feeding control is very important in the water treatment process. Coagulant feeding is related to the raw water quality such as turbidity, alkalinity, water temperature, pH and so on. However, since the process of chemical reaction has not been clarified so far, coagulant dosing rate has been decided by jar-test. In order to overcome the difficulty mentioned above, Fuzzy Neural Network to fuse fuzzy logic and neural network was proposed, and the scheme was applied to the automatic determination of coagulant dosing rate. This algorithm can automatically identify the if-then rules, tune the membership functions by utilizing expert's experimental data. The proposed scheme is evaluated by computer simulation and interfaced with coagulant feeder operated by magnetic flowmeter, control valve and PLC. It is shown that coagulant feeding according to real time sensing of water quality is very effective.

• 전기학회논문지
• /
• 제62권11호
• /
• pp.1621-1627
• /
• 2013

This paper compares power losses between voltage controlled before and after using power conversion device in AC feeding system. For this purpose we present voltage control procedures and criteria and model high speed line and train using PSCAD/EMTDC to compare power losses in various feeding condition. Power losses of the simulation result in power control before and after in single point feeding system was reduced maximum 0.37 MW(23.8 %) and average 0.23 MW(20.5 %) when one vehicle load operates maximum load condition. When three vehicles operate maximum load condition in one feeder section, power losses after voltage control was reduced 1.03 MW(49.5%) compared to before voltage control. And, power loss of parallel feeding system is reduced the average 0.08 MW(7.2 %) compared to the single feeding system. In conclusion, adaptive voltage control method using power conversion device can reduce power losses compared with existing method.

• 한국전자파학회논문지
• /
• 제24권2호
• /
• pp.113-121
• /
• 2013

본 논문에서는 재구성 급전 구조를 갖는 4중 편파 안테나 시스템을 제안한다. 제안된 안테나는 4중 편파(수직/수평 선형 편파와 우선회/좌선회 원형 편파 혹은 45도 경사각을 갖는 수직/수평 선형 편파)를 갖기 위한 급전부와 그에 따른 편파 수신을 위한 패치 안테나로 구성된다. 본 안테나에서는 임의의 수신 신호에 대하여, 전기적 스위치를 통하여 재구성이 가능한 편파를 갖도록 설계되었으며, 제작된 안테나의 급전부의 삽입 손실은 약 1.2 dB이며, 안테나의 원형 편파 3 dB 축비 대역폭은 약 2 %, 안테나 이득은 약 4 dBi(c)로 측정되었다.

• Journal of electromagnetic engineering and science
• /
• 제12권2호
• /
• pp.155-160
• /
• 2012

A wideband circularly polarized pinwheel-shaped planar monopole antenna fed by a wideband feeding network is presented in this paper. The proposed antenna is formed by four wideband planar monopole antenna elements with aquadruple feeding network in order to improve the performance of circular polarization. Additionally, the antenna, which is introduced here, has a high gain in the z axis direction because of its folded antenna structure. The attractive characteristics of the proposed antenna are the wide impedance bandwidth of 87.3 % (1 GHz to 2.55 GHz), the 3 dB axial ratio (AR) bandwidth of 92.3 % (1.05 GHz to 2.85 GHz), and the maximum gain within the 3 dB AR bandwidth is about 8.24 dBic.

• 대한전자공학회논문지
• /
• 제19권6호
• /
• pp.80-83
• /
• 1982

X-밴드 주파수에서 λg/4 개방 마이크로스트립 선로 급전형 스로트 점렬을 구현하였다. 최적 급전점은 실험적으로 결정하였고 스로트 점각의 여러 주파수에서 입력 임피던스와 복재 패턴을 측정하였으며 다소 다른 길이의 16개 소자와 본 논문에서 제시한 급전 선로를 사용하여 주파수 대역을 증가시켜 보았다. A quarter-wavelength open circuited microstripline slot array is realized at X-band froquency. The optimal feeding point is experimentally determined. The input impedance of the slot array for various frequencies and its radiation pattern are measured. The bandwidth of the slot array is increased by using the 4×4 elements which are slightly different in length and feeding network which is suggested in this papers.

• 전기학회논문지
• /
• 제65권5호
• /
• pp.883-887
• /
• 2016

The power supply system in Korean electrified railway has adopted AT feeding. If a fault occurs in some substation for any reason, the vicinity substation must feed electric power on the outage substation through catenary. So, the feeding distance grows twice of the normal state at extended feeding condition. If substation's feeding distance is longer than normal condition, the catenary impedance and train to supply electric power from the substation. Therefore, the severe voltage drop can occur and power supply shall be not allowed. This paper presents the model of compensator against voltage drop using multi-port network algorithm. Whole traction power supply system can be analyzed with this model. Computer simulation including this model is performed based on real train schedule and increased schedule in case studies.

• 제어로봇시스템학회논문지
• /
• 제10권11호
• /
• pp.1100-1106
• /
• 2004

In this report, a self-organizing fuzzy neural network is proposed to control chemical feeding, which is one of the most important problems in water treatment process. In the case of the learning according to raw water quality, the self-organizing fuzzy network, which can be driven by plant operator, is very effective, Simulation results of the proposed method using the data of water treatment plant show good performance. This algorithm is included to chemical feeder, which is composed of PLC, magnetic flow-meter and control valve, so the intelligent control of chemical feeding is realized.

• 사물인터넷융복합논문지
• /
• 제2권3호
• /
• pp.31-35
• /
• 2016

IoT기술은 최근 수년간 급격히 발달하였고, 많은 분야에 적용되고 있다. 수산업 분야에서는 IoT 플랫폼을 활용한 양식장 수질관리 시스템이 개발되어 생산성 향상과 근로 환경 개선에 많은 도움을 주고 있다. 본 연구에서는 내수면 양식장 수질관리 시스템에서 더욱 발전하여, 수질 연동형 자동 급이 시스템을 설계함으로써 보다 효율적이고 체계적인 양식장 관리 시스템을 제안한다. IoT 전용망인 LPWA를 활용하여 내수면 양식장 환경에 적합하고, 저전력과 낮은 통신비용으로 상용화를 위한 경제성을 확보하였다. 본 연구를 통하여 내수면 양식 산업의 발전은 물론, 빅데이터 분석을 통한 양식 기술 발전에 일조할 것으로 기대한다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 B
• /
• pp.1236-1238
• /
• 2001

The electrified railway has various power supply schemes. Although the identical trains are operated in same condition and the impedance of track are equal, the genealogy impedance of track is changed according to composition method of feeding scheme. So, the collection voltage of train and supplying power from railway substation are greatly unlike. For simulation of collection voltage and power supply according to feeding scheme, using 6-port network analysis proposed previously simulate collection voltage and supply power according to feeding scheme(Parallel Post feeding system, normal feeding system and tie feeding system) and compare and investigate each characteristics.