• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.189-194
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• 1994

Adaptive control systems based upon the command generator tracker(CGT) approach have attracted considerable interest because of the simple structure of its adaptive controller. Some attempts to such improve the adaptive control algorithm, for the sake of the application to broader class of plants, are made. Recently, Su and Sobel(1992) proposed that those schemes can be treated by an unified theory using a metasystem representation with some types of supplementary dynamics. However, in their method, it is difficult to find the dynamic compensator, which is proper and output feedback stabilizable, for the uncertain plant. This paper proposes a new design method of such supplementary dynamics and some parameters of adaptive control system for linear time invariant SISO plants. The method gives a concrete and systematic design method using only a few priori knowledge of the plant.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.253-256
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• 1996

In this paper, A new time-varying sliding surface design using eigenvalue locus is proposed to achieve fast and robust in a class of high-order uncertain dynamic system. A moving sliding surface(MSS) was proposed earlier for the second-order variable structure control systems(VSCS). This methodology led to fast and robust control responses of the second-order VSCS. However, the moving algorithm of the MSS was too complicated to be employed the high-order VSCS. To resolve this problem, we propose a new moving algorithm that switching surface moves such that the eigenvalues of equivalent system in the sliding mode have a predetermined locus. Using the proposed surface fast and robust behaviors are accomplished. The problem of chattering can be eliminated by using a boundary layer of switching surface. The efficiency of proposed algorithm is illustrated by an application to four-order workbench.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권4호
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• pp.251-258
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• 2005

Automatic document classification may differ significantly according to the characteristics of documents that are subject to classification, as well as classifier's performance. This research identifies e-mail document's characteristics to apply a three-step preprocessing algorithm that can minimize e-mail document's atypical characteristics. In the first 5go, uncertain based sampling algorithm that used Mean Absolute Deviation(MAD), is used to address the question of selection learning document for the rule generation at the time of classification. In the subsequent stage, Weighted vlaue assigning method by attribute is applied to increase the discriminating capability of the terms that appear on the title on the e-mail document characteristic level. in the third and last stage, accuracy level during classification by each category is increased by using Naive Bayesian Presumptive Algorithm's Dynamic Threshold. And, we implemented an E-Mail Recommendtion System using a three-step preprocessing algorithm the enable users for direct and optimal classification with the recommendation of the applicable category when a mail arrives.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.490-495
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• 1998

In this paper an asymmetric hydraulic actuator which consists of single acting cylinder and servo valve is modeled for a quarter car active suspension system. This model regards the force as an internal state rather than a control input. The control input of the model is the sum of oil flows that pass through the valve's orifices. The resulting dynamic equation in the state space ap-pears a feedback connection of a nominal linear time in-variant term with a nonlinear bounded uncertain block. Since this model makes it possible to eliminate the force control phase, analysis and controller design are made straightforward and simple. Well known LQR method is then applied. Simulation and test rig experiment show the effectiveness of this approach in modeling and control.

• 한국항공운항학회지
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• 제21권3호
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• pp.1-8
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• 2013

An application of adaptive flight controller is required for the non-linear and high uncertain system that configuration of tiltrotor aircraft is dramatically changed from rotary wing mode to fixed wing mode. In this paper, the applicable adaptive controller for the tiltrotor aircraft was designed using Neural Networks and DMI (Dynamic Model Inversion). The performance of the SCAS (Stability and Control Augmentation System) was simulated against manned military specification, using the fullscale model of 'Smart UAV(Unmanned Aerial Vehicle)' developed by Korea Aerospace Research Institute. And Neural Networks based adaptive controller was verified through its whole operating envelope using the established HQ (Handling Quality) criteria.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.1012-1019
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• 2016

A robust control intended for a nonholonomic mobile robot is considered to guarantee good tracking a desired trajectory. The main drawbacks of the mobile robot model are the existence of nonholonomic constraints, uncertain system parameters and un-modeled dynamics. in order to overcome these drawbacks, we propose a robust control based on Lyapunov theory associated with sliding-mode control, this solution shows good robustness with respect to parameter variations, measurement errors, noise and guarantees position and velocity tracking. The global asymptotic stability of the overall system is proven theoretically. The simulation results largely confirm the effectiveness of the proposed control.

• Structural Engineering and Mechanics
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• 제5권2호
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• pp.115-126
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• 1997

Importance sampling methods have been developed with the aim of reducing the computational costs inherent in Monte Carlo methods. This study proposes a new algorithm called the adaptive kernel method which combines and modifies some of the concepts from adaptive sampling and the simple kernel method to evaluate the structural reliability of time variant problems. The essence of the resulting algorithm is to select an appropriate starting point from which the importance sampling density can be generated efficiently. Numerical results show that the method is unbiased and substantially increases the efficiency over other methods.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.377-382
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• 2005

The tools, methods and measures used for project control reflect underlying theories of management. Management theory has been neglected in the construction industry, which has rather focused on tools and neglected theory. This paper contributes to the theory of project management by introducing and developing two fundamental and competing conceptualizations of management: MBM (Managing-by-Means) and MBR (Managing-by-results). Current project control and performance measurement practice is based on MBR. However, project control based on MBR may not be appropriate for managing dynamic projects. The paper present the Last Planner^TM System (LPS) and Process Variance Control (PVC) as examples of methods reflecting the MBM view. It is argued first that the MBM view is appropriate for managing uncertain, complex and quick projects. The paper also explores how MBR tools and techniques may be appropriately used within an MBM framework.

• 동력기계공학회지
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• 제21권1호
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• pp.30-36
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• 2017

In robot industries, the request to obtain a high efficiency and accurately controlled electric actuator has been growing. Nevertheless, the effectiveness of electric actuators is significantly affected by the presence of factors such as nonlinearity, uncertain disturbance and unknown dynamics. Therefore, it makes difficult to derive an exact mathematical model of the controlled system. In this paper, a new method for easily recognizing and regenerating robot motions used in small size industries such as painting and welding parts is proposed. Instead of modeling the entire dynamic motion of the robot system, this method is based on the procedure of modeling and controller design for every arm individually. The proposed method does not require complex model and control system such that it gives easy working process to the small size industries. Based on this fact, in this research, the model and PID controller for every arm of the 3 DOF robot system are obtained separately. Some experimental results are implemented to validate the effectiveness of the proposed method.

• 대한안전경영과학회지
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• 제8권4호
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• pp.151-166
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• 2006

One of The standard issue in riding on the wave of the information system(IS) is records of performance, grow unprecedently fast, and has highly uncertain future. Within the framework of IS Evaluation, The main purpose of this study is to suggest performance quality evaluation system as follows, The Integrated Quality Evaluation Model Design(IQEMD) of Information System helps corporations to improve productivity, customer service and corporate competitive power. To respond flexibly this trend, we have to realize that the information system has to keep the most effective optimal information network at the proper time. The existing evaluation method has been concentrated on the evaluation of a degree of the information system maturity focused on static viewpoints. The evaluation of potential factors to affect the future-oriented performance, that can analyze both unit business being able to apply an information system base was used efficiently well and what performance evaluation item was obtained actually, was insufficient relatively. In this paper, An integrated quality evaluation method will analyze a degree of information system maturity in dynamic evaluation viewpoints rather than in static evaluation viewpoints. finally we estimated the relative degree of importance of each determinant using the AHP methodology The validity of the proposed model was also partially proved using two different methods, holistic and historical approach.