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황재승,김시윤,이승우 한국풍공학회 2021 한국풍공학회지 Vol.25 No.2
본 연구에서는 구조물의 진동제어를 위하여 사용되는 가장 대표적인 수동형 제진장치로 알려진 동조질량 감쇠기(Tuned Mass Damper, TMD)의 동적특성을 운영 중에 추정하는 기법에 대해서 다룬다. 동적특성 추정법은 무향칼만필터에 기반하고 있으며, 구조물과 TMD의 계측 가속도를 이용한다. TMD 파라미터 중에 마찰계수를 추정 파라미터로 포함하는 경우와 그렇지 않은 경우로 구분하여 마찰계수가 TMD의 동적특성에 미치는 영향을 평가하였다. 추정된 TMD 파라미터와 TMD에 의해서 분화된 두 개의 인접모드의 동적 특성을 이용하여 제어 대상 모드의 동적특성을 추정하여 제진장치에 의한 제어성능을 평가하였다. 본 연구에서 제안된 TMD 파라미터 추정법을 실 구조물 계측응답에 적용한 결과 안정적인 파라미터 추정이 이루어지는 것을 확인할 수 있었으며 제어성능 평가가 가능함을 검증하였다. In this study, a technique for estimating the dynamic properties of a tuned mass damper (TMD) in operation, a passive vibration device used for vibration control of structure, is addressed. The dynamic parameter estimation method is based on the unscented Kalman filter(UKF) and uses the acceleration response of the target structure and the TMD. Among the TMD parameters, the effect of the friction coefficient on the dynamic characteristics of the TMD was evaluated by considering the cases where the friction coefficient was considered or not. The control performance by TMD was also evaluated by estimating the dynamic characteristics of the target structural mode using the estimated TMD parameters and the dynamic characteristics of the two adjacent modes popped up by the TMD. From the simulation results of applying the proposed parameter estimation method to in-situ structure, it was found that a stable parameter estimation was made, and the evaluation of control performance by TMD can be verified.
소정훈(So Jung-Hun),이봉섭(Lee Bong-Seob),유진수(Yoo Jin-Su),황혜미(Hwang Hye-mi),유권종(Yu Gwon-Jong) 한국태양에너지학회 2010 한국태양에너지학회 논문집 Vol.30 No.6
This paper presents performance estimation approach of grid-connected photovoltaic(PV) system to predict energy yield from irradiance to PV system using normalized yield model for changing meteorological conditions. The accuracy and validity of proposed performance estimation method is identified by compared measured with estimated yield using monitored data. These results will indicate that it is useful to estimate various loss factors causing the system performance obstruction and enhance the lifetime yield of PV system.
김무섭 한국데이터정보과학회 2024 한국데이터정보과학회지 Vol.35 No.1
다변량정칙변동 (multivariate regular variation)은 꼬리지수 (tail index)와 스펙트럴측도 (spectral measure)로 특징지어진다. 타원분포 (elliptical distribution)는 다변량정칙변동의 주요한 하위모형으로 스펙트럴측도의 확률밀도함수에서 꼬리지수가 형태모수로 등장한다. 그래서 최대우도추정법과 더불어 스펙트럴측도추정에서 꼬리지수를 별도로 하는 방법을 고려할 수 있다. 이 논문은 이 단계적방법을 공식화시켜 기존의 최대우도방법과 성능비교를 수행한다. 비교결과 최대우도추정법과 Hill추정량을 이용한 단계추정법이 전반적으로 나은 성능을 보이는 것으로 확인되었다. Multivariate regular variation is characterized by tail index and spectral measure. Elliptical distributions constitute a prominent subclass, where the tail index not only is related to the magnitude of extremes but also plays the role of shape parameter for the spectral measure. Therefore, estimating the shape parameter separately can be considered for doing the spectral measure. This paper formulates the two-stage estimation procedure and conducts a comparison study. As a result, maximum likelihood estimation and the two-stage one with the Hill estimator turned out to perform better than the others.
확률적 머신러닝 모델기반의 리튬이온배터리 파라미터 추정 알고리즘
김민호(Minho Kim),송민석(Minseok Song),임정택(Jeongtaek Lim),함경선(Kyung Sun Ham),이도헌(DOHEON LEE),김태형(Taehyoung Kim) 한국에너지학회 2024 에너지공학 Vol.33 No.1
In this study, a new lithium-ion battery performance degradation model and a stochastic machine learning model-based lithium-ion battery parameter estimation method were proposed and verified through actual battery degradation cycle experiment data. The proposed parameter estimation method based on a stochastic machine learning model requires less battery model operation time compared to other methods, enabling efficient parameter estimation. The lithium-ion battery performance degradation model is an equivalent circuit-based model, but it reflects various electrochemical phenomena, including side reactions on the surface of the anode active material, including the formation of a solid electrolyte interphase (SEI) layer, the loss of positive electrode active material due to mechanical stress-induced fatigue failure is included, and the corresponding decrease in the amount of cyclable lithium. In the proposed method of estimating the parameters of a lithium-ion battery model, a probabilistic machine learning model that can estimate battery model parameters from sensible data such as voltage and current is developed and used to generate virtual experiment data. We proposed a technique for learning and finding optimal battery model parameters based on the learned model. The developed performance degradation model and parameter estimation method were verified based on actual experimental data. Since it is impossible to observe the inside of the battery, correct answers to the battery parameters cannot be obtained, so the model and parameter estimation algorithm are indirectly verified through errors of voltage and temperature. As a result of the verification, the errors in voltage and temperature were found to be 0.676% and 0.207%, respectively.
구간 추정 기법을 이용한 이동통신 시스템의 통화 성공률 시험 방법
황익순(Iksoon Hwang),박재성(Jaesung Park) 한국정보과학회 2010 정보과학회논문지 : 정보통신 Vol.37 No.6
시스템의 성능 요구 사항은 일반적으로 해당 시스템이 제공하는 서비스의 품질과 높은 연관성을 가진다. 예를 들어 이동통신 시스템에서 통화 성공률은 서비스 품질과 직결되는 사항으로 매우 높은 중요도를 가지며 체계적인 성능 시험 방법이 요구되고 있다. 본 논문에서는 구간 추정 기법을 이용하여 이동통신 시스템의 통화 성공률을 시험하는 방안을 제안한다. 또한 제안된 시험 방안을 기반으로 방송통신위원회에서 최근 시행한 3G 이동전화 서비스 품질 평가에서 사용된 판정 기준에 대해 고찰해 보고 문제점에 대해 살펴본다. Performance requirements of a system are usually closely related to the quality of service provided by the system. The call success rate of a mobile communication system is, for example, directly linked with the quality of call service. Therefore, meeting the performance requirements is one of the critical issues during the operation of services as well as in system development. In this paper, we present a testing method for evaluating the call success rate of a mobile communication system by using interval estimation. Also we analyze the criterion used in the evaluation of the quality of 3G mobile communication services which was recently performed by Korea Communications Commission and then discuss the problems.
장완식,신광수,백은석 조선대학교 생산기술연구소 1996 生産技術硏究 Vol.18 No.1
This paper presents three-dimensional robot task using the vision control method. A minimum of two cameras is required to place points on end effecters of n degree-of-freedom manipulators relative to other bodies. This is accomplished using a sequential estimation scheme that permits placement of these points in each of the two-dimensional image planes of monitoring cameras. Estimation model is developed based on a model that generalizes known manipulator kinematics to accommodate unknown relative camera position and orientation, etc. This model uses six uncertainty-of-view parameter estimated by the iteration method. The method is tested experimentally with three-axis manipulator in two ways; a) the estimation model test, b) a three-dimensional point placement task. These results show that control scheme used is precise and robust.