• Computers and Concrete
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• v.31 no.5
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• pp.457-468
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• 2023

Buildings, bridges, and dams are examples of civil infrastructure that play an important role in public life. These structures are prone to structural variations over time as a result of external forces that might disrupt the operation of the structures, cause structural integrity issues, and raise safety concerns for the occupants. Therefore, monitoring the state of a structure, also known as structural health monitoring (SHM), is essential. Owing to the emergence of the fourth industrial revolution, next-generation sensors, such as wireless sensors, UAVs, and video cameras, have recently been utilized to improve the quality and efficiency of building forensics. This study presents a method that uses a target-based system to estimate the dynamic displacement and its corresponding dynamic properties of structures using UAV-based video. A laboratory experiment was performed to verify the tracking technique using a shaking table to excite an SDOF specimen and comparing the results between a laser distance sensor, accelerometer, and fixed camera. Then a field test was conducted to validate the proposed framework. One target marker is placed on the specimen, and another marker is attached to the ground, which serves as a stationary reference to account for the undesired UAV movement. The results from the UAV and stationary camera displayed a root mean square (RMS) error of 2.02% for the displacement, and after post-processing the displacement data using an OMA method, the identified natural frequency and damping ratio showed significant accuracy and similarities. The findings illustrate the capabilities and reliabilities of the methodology using UAV to evaluate the dynamic properties of structures.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.648-653
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• 1993

This paper presents an nonlinear observer scheme for flexible joint robot manipulators. This nonlinear observer scheme is based on the sliding mode method. Sliding controllers have recently been shown to feature excellent robustness and performance properties for specific classes of nonlinear tracking problems. Dynamic equations of flexible joint robot manipulators are derived from the Euler-Lagrange equations by forming the corresponding Lagrangian. Simulation results are presented to show the validness of the proposed nonlinear observer scheme.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.788-791
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• 1996

A mathematical model is developed for thermal solution copolymerization of styrene and acrylonitrile in a continuous stirred tank reactor(CSTR). Computational studies are carried out with the continuous copolymerization system model developed in this work to give the monomer conversion, copolymer composition and the average molecular weights of the copolymer. By performing the dynamic analysis of the reaction system, the polymer properties against the changes in the operating conditions are determined quantitatively. The cascade PID and fuzzy controller show satisfactory performances for both set point tracking and disturbance rejection. Especially, the fuzzy controller is superior to the PID controller.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.734-740
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• 1987

Various kinds of predictive control design methods such as MAC(Model Algorithmic Control), DMC(Dynamic Matrix Control), MC(Extended Horizon Adaptive Control), GPC(Generalized Predictive Control), RHTC(Receding Horizon Tracking Controller), and PVC(PreView Controller) are surveyed and compared in this paper. In addition, stability properties of these control laws known to date are summarized and some new stability results are presented.

• International Journal of Highway Engineering
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• v.11 no.4
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• pp.25-31
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• 2009

In general, it is well known fact that the stone mastic asphalt (SMA) pavement has a high resistance against rutting. However, performance of SMA is not well measured by general method used in the laboratory. The objective of this study is to investigate an applicability of deformation strength ($S_D$) for performance estimation of SMA, and to find out the correlation between rut depth and dynamic stability, and $S_D$ of SMA. This study carried out wheel tracking test and Kim-test with optimum asphalt content (OAC) determined by mix design. The results indicated that the $S_D$ of SMA was very poorer than those of dense-graded asphalt mixtures. $S_D$ showed similar WT dynamic stability and rut-depth level. It was found that Kim-test was not reflected higher rutting resistance of SMA like as indirect tensile strength (ITS) test and Marshall stability test. Also, it was revealed that dynamic stability and rut-depth of WT had some problems to estimate rutting resistance of SMA mixtures.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.4 s.316
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• pp.86-92
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• 2007

A discrete dynamic model for tracking feature points in 2D images is developed. Conventional snake approaches deform a contour to lock onto features of interest within an image by finding a minimum of its energy functional, composed of internal and external forces. The neighborhood around center snaxel is a space matrix, typically rectangular. The structure of the model proposed in this paper is a set of connected vertices. Energy model is designed for its local minima to comprise the set of alternative solutions available to active process. Block on tracking is one dimension, line type. Initial starting points are defined to the satisfaction of indent states, which is then automatically modified by an energy minimizing process. The track is influenced by curvature constraints, ascent/descent or upper/lower points. The advantages and effectiveness of this layer approach may also be applied to feature points tracking of digital image whose pixels have one directional properties with high autocorrelation between adjacent data lines, vertically or horizontally. The test image is the ultrasonic carotid artery image of human body, and we have verified its effect on intima/adventitia starting points tracking.

• Polymer(Korea)
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• v.31 no.6
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• pp.538-542
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• 2007

This study is on the performance analysis of modified asphalts which were prepared by mixing the asphalt with polymer modifiers of varying compositions which were synthesized by the emulsion polymerization method. Thermal properties of mired asphalt were investigated by DSC (differential scanning calorimetry), and dispersion of modifiers in asphalt was investigated by the fluorescence microscope. Dynamic stability and permanent deformation velocities of mixed asphalt were investigated by wheel tracking measurements. Modifier 6 showed the best results in both penetration test and wheel tracking measurement among investigated modifiers, which supports MMA(methyl methacrylate) moiety in modifiers plays better contribution for the enhancement of asphalt performance than styrene moiety does.

• Smart Structures and Systems
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• v.29 no.4
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• pp.617-624
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• 2022

A new intelligent adaptive control scheme was proposed that combines the control based on interference observer and fuzzy adaptive s-curve for flight path tracking control of unmanned aerial vehicle (UAV). The most important contribution is that the control configurations don't need to know the uncertainty limit of the vehicle and the influence of interference is removed. The proposed control law is an integration of fuzzy control estimator and adaptive proportional integral (PI) compensator with input. The rated feedback drive specifies the desired dynamic properties of the closed control loop based on the known properties of the preferred acceleration vector. At the same time, the adaptive PI control compensate for the unknown of perturbation. Additional terms such as s-surface control can ensure rapid convergence due to the non-linear representation on the surface and also improve the stability. In addition, the observer improves the robustness of the adaptive fuzzy system. It has been proven that the stability of the regulatory system can be ensured according to linear matrix equality based Lyapunov's theory. In summary, the numerical simulation results show the efficiency and the feasibility by the use of the robust control methodology.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1447-1453
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• 2014

This paper proposes the new method based on the availability of three points measurement and convexity of photovoltaic (PV) curve characteristic at the maximum power point (MPP). In general, the MPP tracking (MPPT) function is the important part of all PV systems due to their power-voltage (P-V) characteristics related with weather conditions. Then, the analog-to-digital converter (ADC) and low pass filter (LPF) are required to measure the voltage and current for MPPT by the digital controller, which is used to implement the PV power conditioning system (PCS). The measurement and quantization error due to rounding or truncation in ADC and the delay of LPF might degrade the reliability of MPPT. To overcome this limitation, the proposed method is proposed while improving the performances in both steady-state and dynamic responses based on the detailed investigation of its properties for availability and convexity. The performances of proposed method are evaluated with the several case studies by the PSCAD/EMTDC$^{(R)}$ simulation. Then, the experimental results are given to verify its feasibility in real-time.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.265-270
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• 2001

In this paper, a robust controller is proposed to control a robot manipulator which is governed by highly nonlinear dynamic equations. The controller is computationally efficient since it does not require the dynamic model or parameter values of a robot manipulator. It, however, requires uncertainty bounds which are derived by using properties of revolute joint robot dynamics. The stability of the robot with the controller is proved by using Lyapunov's direct method. The results of computer simulations also show that the robot system is stable, and has excellent trajectory tracking performance.