• 한국항공우주학회지
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• 제34권5호
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• pp.93-100
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• 2006

본 논문에서는 레이더와 원격측정시스템으로부터 수신되는 다중센서자료를 모사하는 시뮬레이터 설계와 이들 자료를 융합하기 위한 알고리듬 개발에 대하여 소개한다. 설계된 데이터 시뮬레이터는 실제 센서 시스템으로부터 얻게 되는 시간의 비동기, 통신지연, 다중 갱신주기들을 갖는 모의센서 자료를 생성하며 실제적인 센서 모델을 이용하여 측정 잡음을 생성한다. 융합알고리듬은 센서 바이어스 상태를 고려한 PVA모델을 기초로 21차 분산형 칼만 필터로 설계되었고, 센서의 이상이나 정상적이 아닌 측정치를 검출하기 위한 로직도 포함되었다. 설계된 알고리듬을 시뮬레이터에서 생성한 모의 자료 및 실제 자료를 적용하여 검증하였다.

• 한국통신학회논문지
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• 제33권1A호
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• pp.67-73
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• 2008

최근 무선 통신 및 전자 기술의 발달로 저가, 저전력, 소형이면서 라디오 신호를 이용한 근거리 무선 통신이 가능한 스마트 센서가 일반적으로 배치될 것으로 기대된다. 센서 네트워크에서 각 노드는 음파, 지진, 적외선, 정지/이동 등 다양한 센서들로 이뤄지며 이러한 노드들은 특정 지역에 집단적으로 네트워크를 구성하게 되는데, 이를 센서 네트워크라고 한다. 본 논문에서는 간단히 한국통신학회의 논문작성법에 대하여 설명하고자 합니다. 기존에 연구되고 있는 무선 네트워크가 높은 데이터 전송률 및 처리성능을 기본으로 하는 컴퓨팅에 초점을 둔 반면에, 센서 네트워크는 기존 무선 네트워크와는 매우 상이한 응용 요구사항을 갖는다. 즉 센서들은 CPU와 통신기능, 센싱 기능을 같춘 자율적인 컴퓨팅 단말 기능을 수행한다고 할 수 있다. 그러므로 본 논문에서는 USN기반 다중접속이 가능한 기반 기술로 무선 센서 네트워크에서 다중접속 프로토콜을 이용하여 무선 통신상에서 원활한 통신이 이루어 질수 있도록 미들웨어 및 알고리즘을 분석하여 성능 평가를 하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.185-188
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• 1993

The goal of this paper is to develop an on-board controller for a model helicopter's hovering attitude control, using i8096 one-chip microcontroller. Required controller algorithm is programmed in ASM-96 assembly language and downloaded into an i8096 microcontroller. The performance of hovering flight using this system is verified by experiments with the model helicopter mounted on an instrumented flight stand where 3 potentiometers and an optical proximity sensor measure te attitude and main rotor speed of the helicopter.

• Smart Structures and Systems
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• 제20권3호
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• pp.311-328
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• 2017

The characteristics of boundary layers have significant effects on the aerodynamic forces and vibration of the wind turbine blade. The incorporation of active trailing edge flaps (ATEF) into wind turbine blades has been proven as an effective control approach for alleviation of load and vibration. This paper is aimed at investigating the effects of external trailing edge flaps on the flow pattern and velocity distribution within a boundary layer of a NREL 5MW reference wind turbine, as well as designing a new type of velocity sensors for future validation measurements. An aeroelastic-aerodynamic simulation with FAST-AeroDyn code was conducted on the entire wind turbine structure and the modifications were made on turbine blade sections with ATEF. The results of aeroelastic-aerodynamic simulations were combined with the results of two-dimensional computational fluid dynamic simulations. From these, the velocity profile of the boundary layer as well as the thickness variation with time under the influence of a simplified load case was calculated for four different blade-flap combinations (without flap, with $-5^{\circ}$, $0^{\circ}$, and $+5^{\circ}$ flap). In conjunction with the computational modeling of the characteristics of boundary layers, a bio-inspired hair flow sensor was designed for sensing the boundary flow field surrounding the turbine blades, which ultimately aims to provide real time data to design the control scheme of the flap structure. The sensor element design and performance were analyzed using both theoretical model and finite element method. A prototype sensor element with desired bio-mimicry responses was fabricated and validated, which will be further refined for integration with the turbine blade structures.

• Nuclear Engineering and Technology
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• 제42권2호
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• pp.219-230
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• 2010

In nuclear power plants (NPPs), periodic sensor calibrations are required to assure that sensors are operating correctly. By checking the sensor's operating status at every fuel outage, faulty sensors may remain undetected for periods of up to 24 months. Moreover, typically, only a few faulty sensors are found to be calibrated. For the safe operation of NPP and the reduction of unnecessary calibration, on-line instrument calibration monitoring is needed. In this study, principal component-based auto-associative support vector regression (PCSVR) using response surface methodology (RSM) is proposed for the sensor signal validation of NPPs. This paper describes the design of a PCSVR-based sensor validation system for a power generation system. RSM is employed to determine the optimal values of SVR hyperparameters and is compared to the genetic algorithm (GA). The proposed PCSVR model is confirmed with the actual plant data of Kori Nuclear Power Plant Unit 3 and is compared with the Auto-Associative support vector regression (AASVR) and the auto-associative neural network (AANN) model. The auto-sensitivity of AASVR is improved by around six times by using a PCA, resulting in good detection of sensor drift. Compared to AANN, accuracy and cross-sensitivity are better while the auto-sensitivity is almost the same. Meanwhile, the proposed RSM for the optimization of the PCSVR algorithm performs even better in terms of accuracy, auto-sensitivity, and averaged maximum error, except in averaged RMS error, and this method is much more time efficient compared to the conventional GA method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.75.5-75
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• 2001

In this paper, we study design of a ILQ(Inverse Linear Quadratic optimal control) looper control system for hot strip mills. The looper which is placed between stands plays an important role in controlling strip width by regulating strip tension variation generated from the velocity difference of main work rolls. A Looper servo controller is designed by ILQ control theory which is an inverse problem of LQ(Linear Quadratic optimal control) control. The mathematical model for looper system is obtained by Taylor´s linearization of nonlinear differential equations. Then we designed linear controller for linearization model by using the ILQ control algorithm. Thereafter this controller is applied to the nonlinear model for model identification. As a result, we show the controller´s robustness for the model error, external disturbance and sensor noise.

• 대한공업교육학회지
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• 제33권2호
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• pp.273-286
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• 2008

수중에서 UUV(Unmanned Underwater Vehicle)에 장착되는 수중 음향 센서 배열은 UUV의 측면이나 전면에 부착하여 외부 신호를 탐지하게 된다. 이러한 센서 배열은 UUV의 특성상 곡면배열(Conformal array) 형태이며 유체 유기 소음의 영향을 받는다. 따라서 본 논문에서는 탄성층에 삽입된 하이드로폰이 외부 유입 소음의 영향을 받는 정도를 해석하였다. 유입 소음은 난류 경계층에서 발생하는 Corcos 모델을 이용하였고 주파수 밀도 함수를 이용하여 수치해석 하였다. x-방향의 파수인 kx에 다른 전달함수의 특성은 탄성층의 두께가 커질수록 전달함수의 적분값은 적어지므로 소음의 영향은 줄어드는 것으로 나타났다. 또한 탄성층 및 고정판의 탄성계수, 밀도 등의 변화가 전달함수 값의 변화를 일으키는지를 조사하였다. 향후 이러한 연구는 UUV에 장착되는 곡면 배열 센서의 설계에 활용할 수 있을 것으로 판단된다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 춘계학술대회
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• pp.155-159
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• 1995

A design method that can easily construct intelligent patient monitoring systems is proposed. To achieve the design method, the SES/MB concept and a discrete event-based logic control formalism based on a set theory is introduced. In this control paradigm the controller expects to receive confirming sensor responses to its control commands within definite time windows determined by DEVS model of the system under control. Because data to be used for rule-based symbolic reasoning are to be abstracted, several AI methods are applied the processes. These methods are applied to intelligent patient monitoring systems so that they facilitate transformation from low level raw data to high level linguistic data. Model-based system representations have advantages of reusability, extensibility, flexsibility, independent testability and encapsulation.

• Ocean Systems Engineering
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• 제9권4호
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• pp.391-407
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• 2019

Tracking the location (position) of a surface or underwater marine vehicle is important as part of guidance and navigation. While the Global Positioning System (GPS) works well in an open sea environment but its use is limited whenever testing scaled-down models of such vehicles in the laboratory environment. This paper presents the design, development and implementation of a low energy ultrasonic augmented single beacon-based localization technique suitable for such requirements. The strategy consists of applying Extended Kalman Filter (EKF) to achieve location tracking from basic dynamic distance measurements of the moving model from a fixed beacon, while on-board motion sensor measures heading angle and velocity. Iterative application of the Extended Kalman Filter yields x and y co-ordinate positions of the moving model. Tests performed on a free-running ship model in a wave basin facility of dimension 30 m by 30 m by 3 m water depth validate the proposed model. The test results show quick convergence with an error of few centimeters in the estimated position of the ship model. The proposed technique has application in the real field scenario by replacing the ultrasonic sensor with industrial grade long range acoustic modem. As compared with the existing systems such as LBL, SBL, USBL and others localization techniques, the proposed technique can save deployment cost and also cut the cost on number of acoustic modems involved.

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1756-1768
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• 2021

The containment filtered venting system (CFVS) filters the atmosphere of the containment building and discharges a part of it to the outside environment to prevent containment overpressure during severe accidents. The Korean CFVS has a tank that filters fission products from the containment atmosphere by pool scrubbing, which is the primary decontamination process; however, prediction of its performance has been done based on researches conducted under mild conditions than those of severe accidents. Bubble behavior in a pool is a key parameter of pool scrubbing. Therefore, the bubble behavior in the pool was analyzed under various injection flow rates observed at the venturi nozzles used in the Korean CFVS using a wire-mesh sensor. Based on the experimental results, void fraction model was modified using the existing correlation, and a new bubble size prediction model was developed. The modified void fraction model agreed well with the obtained experimental data. However, the newly developed bubble size prediction model showed different results to those established in previous studies because the venturi nozzle diameter considered in this study was larger than those in previous studies. Therefore, this is the first model that reflects actual design of a venturi scrubbing nozzle.