Bu-Kyeong Park

In the field of stability analysis for time-delay systems, finding precise bounds of integral/summationforms of quadratic functions plays a key role in reducing the conservatism. Consequently, there have been manyattempts to develop inequalities yielding much tighter bounds. This paper develops novel inequalities using intermediateterms called auxiliary functions, which includes the existing inequalities as special cases. The stabilityconditions for continuous/discrete time-delay systems are der

This paper extends the results of the stability criterion, introduced in the literature, to the problem of stabilization for systems with time-varying delays. Unfortunately, the delay-dependent stabilization conditions using state/output-feedback controllers are not formulated as LMIs. To achieve a better degree of freedom in relaxing the resultant nonlinear terms, we do not assume any restriction on the form of variables, which is a generally adopted procedure in the structure-imposing relaxati

This article surveys the control theoretic study on time delay systems. Since time delay systems are infinite dimensional, there are not analytic but numerical solutions on almost analysis and synthesis problems, which implies that there are a tremendous number of approximated solutions. To show how to find such solutions, several results are summarized in terms of two different axes: 1) theoretic tools like integral inequality associated with the derivative of delay terms, Jensen inequality, lo

In this paper, we propose a novel defects inspection algorithm for TFT-LCD panels. We first compensate the distorted image caused by the camera distortion and the uneven illumination environment using the least squares method and the bezier surface. We find a starting point of each pattern for restricting each pattern. A clean image is compared to each pattern to find defects using modified PCSR-G algorithm. The simulation example shows that our algorithm not only inspects the defects well, but

For underwater vehicles, the use of sensors such as cameras and laser scanners is limited by the difference in environment compared to robots designed to work on dry land. In underwater environments, if use is made of sound signals, valuable information can be obtained. The most important application is the localization of underwater sound sources. The estimated location of a sound source can be used to control underwater robots or submarines. Thus, the purpose of this research is to estimate th

Over the past few decades, the stability issues of linear time-varying delay systems have garnered significant attention in academia. Numerous studies have been reported in the literature, focusing on obtaining less conservative stability conditions expressed in the form of Linear Matrix Inequalities. This paper firstly provides an investigation into numerical techniques developed to estimate the upper bound of the single integral term arising from the time derivative of double integral Lyapunov

In this paper, we present a dynamic output-feedback receding horizon H∞ controller for linear discrete-time systems with disturbance. The controller is obtained numerically from the finite horizon output-feedback H∞ optimization problem, which is, in fact, hardly solved analytically. Under a matrix inequality condition on the terminal weighting matrix, the monotonic decreasing property of the cost is shown. This property guarantees both the closed-loop stability and the H∞ norm bound. Then, we e

For a smooth transition between consecutive paths, conventional robot controllers usually generate a transition trajectory by blending consecutive paths in a time coordinate. However, this has two inherent drawbacks: the shape of a transition path cannot be designed coherently and the speed during transition is uncontrollable. To overcome these problems, this paper provides a path-level, rather than trajectory-level, smooth transition method with the curvature bound between non-smoothly connecte

This paper proposes the soak time estimation method using the slope of control output in heat treatment process. The soak time is the time at which the center temperature of the steel and ambient temperature of the steel reach the target temperature. The center temperature of the steel is needed to find the soak time, but it is difficult to always measure because of the industrial furnace structure. By calculating the relation between soak time and control output, the proposed method can find th

Recently, some novel researches regarding the state estimation for power distribution system have been focused on the dynamic state estimation algorithm due to trend abrupt changes in the distribution system such as actions of prosumers. The previous works studied the Kalman filter for nonlinear system such as extended Kalman filter, unscented Kalman filter. They assume that the state transient model follows smoothing model of the previous states. However, it is hard to set the smoothing coeffic

This paper deals with estimating the acid concentration of pickling process using the Volterra inputs. To estimate the acid concentration, the whole pickling process is represented by the grey box model consists of the white box dealing with known system and the black box dealing with unknown system. Because there is a possibility of nonlinear term in the unknown system, the Volterra series are used to estimate the acid concentration. For the white box modeling, the acid tank solution level and

This paper proposes a variable step-size diffusion least-mean-square algorithm based on an eventtriggered combination method. While much of the existing research in distributed system estimation focuses on improving the convergence rate and accuracy, relatively little attention has been paid to energy efficiency in communications. Thus, this paper proposes an algorithm that aims to reduce communication cost with minimal performance degradation. A variable step size is proposed to achieve stable