• Title/Summary/Keyword: sequential estimation

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Uncertainty Analysis of Spatial Characteristics Related to Probability Rainfall Estimation Using Sequential Indicator Simulation (Sequential Indicator Simulation을 이용한 확률강우량의 공간적 불확실성 평가)

  • Hwang, Soonho;Kang, Moon Seong
    • Proceedings of the Korea Water Resources Association Conference
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    • 2017.05a
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    • pp.350-350
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    • 2017
  • 저수지의 설계홍수량 산정 시 인근의 기상관측 자료를 활용하고 있으나 인근에 기상관측 자료가 없거나 저수지 배후 유역이 큰 경우에는 단일 기상관측 자료를 이용하기에는 한계가 있다. 따라서 실무적으로 지점별 기상관측소의 자료를 이용하여 설계홍수량을 산정할 때에는 각 관측소 자료를 이용하여 확률강우량을 산정하고 Thiessen 가중평균을 한 후 면적우량환산계수 (ARF)를 곱하여 사용하고 있는데, Thiessen 방법의 경우 방법이 간단하지만 지형 고도 효과는 무시되고 우량계의 지배면적에 의한 우량계의 분포 상태만을 고려하게 된다. 그러므로 설계홍수량 산정시 사용되는 Thiessen 방법은 공간적 불확실성을 내포하고 있고, 특히 소규모 저수지의 설계홍수량을 산정하는 경우에는 저수지 유역의 국소적인 특징을 나타내기 어렵다. 본 연구에서는 설계홍수량 산정 시 저수지 위치에 해당하는 확률강우량의 공간적 불확실성을 평가하기 위하여 SIS(Sequential Indicator Simulation) 방법을 이용하였다. SIS 방법은 Kriging 기법과 마찬가지로 베리오그램으로부터 얻어지는 공간적 상관관계를 기반으로 하고 있는 방법으로 Kriging 기법과 달리 공간분포의 국소적인 특성을 평가할 수 있다는 장점을 가지고 있다.

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Experimental Study for Modal Parameter Estimation of Structural Systems (구조물의 자유진동특성 추정을 위한 실험적 연구)

  • 윤정방;이형진
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1994.10a
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    • pp.175-182
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    • 1994
  • As for the safety evaluation of existing large-scale structures, methods for estimation of the structural and dynamic properties are studied. Sequential prediction error method in time domain and improved FRF estimator in frequency domain are comparatively studied. For this purpose, impact tests of 2 bay 3 floor steel frame structure are performed. Results from both methods are found to be consistent to each others, however those from the finite-element analysis are slightly different from experimental results.

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A Bayes Reliability Estimation from Life Test in a Stress-Strength Model

  • Park, Sung-Sub;Kim, Jae-Joo
    • Journal of the Korean Statistical Society
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    • v.12 no.1
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    • pp.1-9
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    • 1983
  • A stress-strength model is formulated for s out of k system of identical components. We consider the estimation of system reliability from survival count data from a Bayesian viewpoint. We assume a quadratic loss and a Dirichlet prior distribution. It is shown that a Bayes sequential procedure can be established. The Bayes estimator is compared with the UMVUE obtained by Bhattacharyya and with an estimator based on Mann-Whitney statistic.

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Activity estimation in a biocatalyst reactor (생촉매 반응기에서의 활성도 추정)

  • 이중헌;유영제;홍주안
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.637-642
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    • 1987
  • In immobilized cell reactors, effective cell mass is a very important parameter which must be estimated during operation for control and regeneration of biocatalyst. In this report, the effective cell mass in immobilized cell reactor was studied using a sequential estimation method. An immobilized yeast reactor was operated in batch recycle mode. The states of the immobilized cell reactor could be estimated from the process data using an extended Kalman filter.

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Development of Vision System Model for Manipulator's Assemble task (매니퓰레이터의 조립작업을 위한 비젼시스템 모델 개발)

  • 장완식
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.6 no.2
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    • pp.10-18
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    • 1997
  • This paper presents the development of real-time estimation and control details for a computer vision-based robot control method. 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 know 4-axis Scorbot manipulator kinematics to accommodate unknown relative camera position and orientation, etc. This model uses six uncertainty-of-view parameters estimated by the iteration method. The method is tested experimentally in two ways : First the validity of estimation model is tested by using the self-built test model. Second, the practicality of the presented control method is verified in performing 4-axis manipulator's assembly task. These results show that control scheme used is precise and robust. This feature can open the door to a range of application of multi-axis robot such as deburring and welding.

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Optimal Measurement Placement for Static Harmonic State Estimation in the Power Systems based on Genetic Algorithm

  • Dehkordl, Behzad Mirzaeian;Fesharaki, Fariborz Haghighatdar;Kiyournarsi, Arash
    • Journal of Electrical Engineering and Technology
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    • v.4 no.2
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    • pp.175-184
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    • 2009
  • In this paper, a method for optimal measurement placement in the problem of static harmonic state estimation in power systems is proposed. At first, for achieving to a suitable method by considering the precision factor of the estimation, a procedure based on Genetic Algorithm (GA) for optimal placement is suggested. Optimal placement by regarding the precision factor has an evident solution, and the proposed method is successful in achieving the mentioned solution. But, the previous applied method, which is called the Sequential Elimination (SE) algorithm, can not achieve to the evident solution of the mentioned problem. Finally, considering both precision and economic factors together in solving the optimal placement problem, a practical method based on GA is proposed. The simulation results are shown an improvement in the precision of the estimation by using the proposed method.

A study on the rigid bOdy placement task of robot system based on the computer vision system (컴퓨터 비젼시스템을 이용한 로봇시스템의 강체 배치 실험에 대한 연구)

  • 장완식;유창규;신광수;김호윤
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.1114-1119
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    • 1995
  • This paper presents the development of estimation model and control method based on the new computer vision. This proposed control method is accomplished using a sequential estimation scheme that permits placement of the rigid body in each of the two-dimensional image planes of monitoring cameras. Estimation model with six parameters is developed based on a model that generalizes known 4-axis scara robot kinematics to accommodate unknown relative camera position and orientation, etc. Based on the estimated parameters,depending on each camers the joint angle of robot is estimated by the iteration method. The method is tested experimentally in two ways, the estimation model test and a three-dimensional rigid body placement task. Three results show that control scheme used is precise and robust. This feature can open the door to a range of application of multi-axis robot such as assembly and welding.

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Estimation of Localized Structural Parameters Using Substructural Identification (부분구조 추정법을 이용한 국부구조계수추정)

  • 윤정방;이형진
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1996.04a
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    • pp.119-126
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    • 1996
  • In this paper, a method of substructural identification is presented for the estimation of localized structural parameters. for this purpose, an auto-regressive and moving average with stochastic input (ARMAX) model is derived for the substructure to process the measurement data impaired by noises. The sequential prediction error method is used fer the estimation of unknown localized parameters. Using the substructural method, the number of unknown parameters can be reduced and the convergence and accuracy of estimation can be improved. For some substructures, the effect of the input excitation is expressed in terms of the responses at the inferences with the main structure, and substructural identification may be carried out without measuring the actual input excitation to the whole structure. Example analysis is carried out for idealized structural models of a multistory building and a truss bridge. The results indicate that the present method is effective and efficient for local damage estimation of complex structures.

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A Study on Rigid body Placement Task of based on Robot Vision System (로봇 비젼시스템을 이용한 강체 배치 실험에 대한 연구)

  • 장완식;신광수;안철봉
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.11
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    • pp.100-107
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    • 1998
  • This paper presents the development of estimation model and control method based on the new robot vision. This proposed control method is accomplished using the sequential estimation scheme that permits placement of the rigid body in each of the two-dimensional image planes of monitoring cameras. Estimation model with six parameters is developed based on the model that generalizes known 4-axis scara robot kinematics to accommodate unknown relative camera position and orientation, etc. Based on the estimated parameters, depending on each camera the joint angle of robot is estimated by the iteration method. The method is experimentally tested in two ways, the estimation model test and a three-dimensional rigid body placement task. Three results show that control scheme used is precise and robust. This feature can open the door to a range of application of multi-axis robot such as assembly and welding.

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Robust 2D human upper-body pose estimation with fully convolutional network

  • Lee, Seunghee;Koo, Jungmo;Kim, Jinki;Myung, Hyun
    • Advances in robotics research
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    • v.2 no.2
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    • pp.129-140
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    • 2018
  • With the increasing demand for the development of human pose estimation, such as human-computer interaction and human activity recognition, there have been numerous approaches to detect the 2D poses of people in images more efficiently. Despite many years of human pose estimation research, the estimation of human poses with images remains difficult to produce satisfactory results. In this study, we propose a robust 2D human body pose estimation method using an RGB camera sensor. Our pose estimation method is efficient and cost-effective since the use of RGB camera sensor is economically beneficial compared to more commonly used high-priced sensors. For the estimation of upper-body joint positions, semantic segmentation with a fully convolutional network was exploited. From acquired RGB images, joint heatmaps accurately estimate the coordinates of the location of each joint. The network architecture was designed to learn and detect the locations of joints via the sequential prediction processing method. Our proposed method was tested and validated for efficient estimation of the human upper-body pose. The obtained results reveal the potential of a simple RGB camera sensor for human pose estimation applications.