• 제어로봇시스템학회논문지
• /
• 제20권2호
• /
• pp.170-174
• /
• 2014

In this paper, an unknown input estimation method via the optimal FIR smoother is proposed for linear discrete-time systems. The unknown inputs are represented by random walk processes and treated as auxiliary states in augmented state space models. In order to estimate augmented states which include unknown inputs, the optimal FIR smoother is applied to the augmented state space model. Since the optimal FIR smoother is unbiased and independent of any a priori information of the augmented state, the estimates of each unknown input are independent of the initial state and of other unknown inputs. Moreover, the proposed method can be applied to stochastic singular systems, since the optimal FIR smoother is derived without the assumption that the system matrix is nonsingular. A numerical example is given to show the performance of the proposed estimation method.

• International Journal of CAD/CAM
• /
• 제6권1호
• /
• pp.193-198
• /
• 2006

Plunge milling is the fastest way to mill away large volumes of metal in the axial direction. The residual volume (inaccessible volume by the plungers) is minimized when selecting a specific direction of filling. This direction is known as the optimal inclination angle for filling of the plunged area. This paper proposes a new algorithm to calculate the optimal inclination angle of filling and to fill the plunged area with multi-plungers sizes. The proposed algorithm uses the geometry of the 2D area of the shape that being cutting to estimate the optimal inclination angle of filling. It is found that, the optimal inclination angle for filling of the plunged area is the same direction as the longer width of the equivalent convex polygon of the boundary contour. The results of the tested examples show that, the residual volume is minimized when comparing the proposed algorithm with the previous method.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제18권2호
• /
• pp.184-191
• /
• 2018

Purpose: The purpose of this study is to propose a method to calculate the optimal preventive maintenance cycle of radar used in the aviation weapon system of ROKAF. Methods: A hybrid model is used to estimate the optimal preventive maintenance cycle in a system that can perform condition based predictive maintenance (CBPM) through continuous diagnosis. The failure data of the radars operating in the military were used to calculate the reliability. Results: According to the research results, the reliability threshold of the radar began to decrease after 5 flights, and decreased rapidly after 12 flights. Since the second check, costs have continued to decline. Conclusion: A method is proposed to determine the cycle of optimal preventive maintenance of radar within operational budget through modeling results between reliability limit and cost for radar. The results can be used to determine the optimal preventive maintenance cycle and frequency of various avionics equipment.

• 한국멀티미디어학회논문지
• /
• 제19권2호
• /
• pp.264-270
• /
• 2016

In this paper, we proposed a method which can detect pedestrians from CCTV video and estimate the height of the detected objects. We separate the foreground using Gaussian mixture model and the pedestrian is detected using the conditions such as the width-height ratio and the size of the candidate objects. In order to obtain the optimal model for estimating the height of pedestrian, we get many training data from the pedestrian whose height is known. Using these training data, we designed optimal Wiener height estimator and used to estimate the height of pedestrians. The height of the pedestrian at various distance is estimated and the accuracy is evaluated. In the experimental results, proposed method shows that it can estimate the height of pedestrian for various positions effectively.

• 대한교통학회지
• /
• 제24권1호
• /
• pp.97-108
• /
• 2006

현재 우리나라에서는 버스 노선의 정류장 수 및 간격 산정을 위해 전문가의 주관적인 판단에 의존하는 경우가 많다. 좀 더 객관적인 절차를 통해 신뢰성 있는 결과를 얻기 위해 최적 정류장 수 및 간격을 구하는 기존 모형들을 살펴보았지만 하차수요와 임의적인 수요분포를 고려하지 못한다는 한계점을 안고 있었다. 본 연구는 기존 모형들의 이러한 한계를 인식하고 수요를 승차와 하차로 구분하고 그 분포에 라라 일정한 구간별로 서로 다른 최적 정류장 수와 간격을 탄력적으로 산출해 낼 수 있는 모형을 정립하였다. 정립된 모형을 다양한 수요분포를 가지는 간단한 예제노선에 적용해본 결과 승차 혹은 하차수요에 비례하여 구간별 정류장 수가 탄력적으로 산출됨을 알 수 있었다.

• 한국물환경학회지
• /
• 제26권4호
• /
• pp.574-579
• /
• 2010

In this study the enzyme inhibition method using dehydrogenase which has been popularly used to estimate ecotoxicity was optimized. When three bacterial strains, Escherichia coli HB101, Enterobacter asburiae KCAD-4, and Aeromonas media KCAD-13, were compared, KCAD-4 was considered as the adequate strain to estimate toxicity because of its sensitivity and reproducibility. The optimal bacterial density was estimated as $5.4{\times}10^9CFU/mL$, at which the maximum sensitivity was observed. The phosphate buffer was suitable for the reaction solution. When the reaction times required for inhibition of enzyme activity by contact of toxicants and for reaction of damaged bacteria and substrate were tested, the optimal value was estimated as 20 min and 2 hrs, respectively. It is expected that the optimized conditions can be used to develop the standardized kits to estimate ecotoxicity of heavy metals in effluent from the industrial wastewater treatment facilities.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2007년도 정기 학술대회 논문집
• /
• pp.481-486
• /
• 2007

The Zienkiewicz-Zhu(Z/Z) error estimate is slightly modified for the hierarchical p-refinement, and is then applied to L-shaped plates subjected to bending to demonstrate its effectiveness. An adaptive procedure in finite element analysis is presented by p-refinement of meshes in conjunction with a posteriori error estimator that is based on the superconvergent patch recovery(SPR) technique. The modified Z/Z error estimate p-refinement is different from the conventional approach because the high order shape functions based on integrals of Legendre polynomials are used to interpolate displacements within an element, on the other hand, the same order of basis function based on Pascal's triangle tree is also used to interpolate recovered stresses. The least-square method is used to fit a polynomial to the stresses computed at the sampling points. The strategy of finding a nearly optimal distribution of polynomial degrees on a fixed finite element mesh is discussed such that a particular element has to be refined automatically to obtain an acceptable level of accuracy by increasing p-levels non-uniformly or selectively. It is noted that the error decreases rapidly with an increase in the number of degrees of freedom and the sequences of p-distributions obtained by the proposed error indicator closely follow the optimal trajectory.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권8호
• /
• pp.996-1003
• /
• 1999

This paper propose a position-speed controller with an estimator which can estimate states and disturbance. The overall control system consists of two parts: the position-speed controller and an estimator. The Kalman filter applied as state-feedback controller is an optimal state estimator applied to a dynamic system that involves random perturbations and gives a linear, unbiased and minimum error variance recursive algorithm to optimally estimate the unknown state. Therefore, we consider the error problem about the servo system modeling and the measurement noise as a stochastic system and implement a optimal state observer, and enhance the estimate performance of position and speed using that. Using two-degree-of freedom(TDOF) conception, we design the command input response and the closed loop characteristics independently. The servo system is to improve the closed loop characteristics without affecting the command imput response. The characteristics of the closed loop system is improved by suppressing disturbance torque effectively with the disturbance observer using a inverse-transfer matrix. Therefore, the performance of overall position-speed controller is enhanced. Finally, the performance of the proposed controller is exemplified by some simulations and by applying the real servo system.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제24권1호
• /
• pp.39-78
• /
• 2020

In this paper, we propose a decoupled local discontinuous Galerkin method for solving the Klein-Gordon-Schrödinger (KGS) equations. The KGS equations is a model of the Yukawa interaction of complex scalar nucleons and real scalar mesons. The advantage of our scheme is that the computation of the nucleon and meson field is fully decoupled, so that it is especially suitable for parallel computing. We present the conservation property of our fully discrete scheme, including the energy and Hamiltonian conservation, and establish the optimal error estimate.

• East Asian mathematical journal
• /
• 제14권1호
• /
• pp.63-76
• /
• 1998

we consider the hp-version to solve non-constant coefficients elliptic equations $-div(a{\nabla}u)=f$ with Dirichlet boundary conditions on a bounded polygonal domain $\Omega$ in $R^2$. In [6], M. Suri obtained an optimal error-estimate for the hp-version: ${\parallel}u-u^h_p{\parallel}_{1,\Omega}{\leq}Cp^{(\sigma-1)}h^{min(p,\sigma-1)}{\parallel}u{\parallel}_{\sigma,\Omega}$. This optimal result follows under the assumption that all integrations are performed exactly. In practice, the integrals are seldom computed exactly. The numerical quadrature rule scheme is needed to compute the integrals in the variational formulation of the discrete problem. In this paper we consider a family $G_p=\{I_m\}$ of numerical quadrature rules satisfying certain properties, which can be used for calculating the integrals. Under the numerical quadrature rules we will give the variational form of our non-constant coefficients elliptic problem and derive an error estimate of ${\parallel}u-\tilde{u}^h_p{\parallel}_{1,\Omega}$.