• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1232-1240
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• 2018

This paper aims at designing an intelligent controller, based on control Lyapunov Function strategy integrated with fabricating discrete model of Buck and Boost converters and analyzing energy changes during the DC/DC progress to realize tracing reference current on Buck and Boost converters. In addition, practical stability phenomenon research and transient performance analysis has been proposed to give an insight to the influence of controller parameters in achieving an enhanced output performance and how the time of sample period affect the error of practical stability will be illustrated. The novelty of this controller in comparison to other schemes lies in the improved performance of practical stability.

• Journal of Power Electronics
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• v.11 no.3
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• pp.375-380
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• 2011

A STATic synchronous COMpensator (STATCOM) is a shunt connected voltage source converter (VSC) based FACTS controller using Gate Turn Off (GTO) power semiconductor devices employed for reactive power control. The operation principal is similar to that of a synchronous condenser. A typical application of a STATCOM is voltage regulation at the midpoint of a long transmission line for the enhancement of power transfer capability and/or reactive power control at the load centre. This paper presents the modeling of STATCOM with twenty four pulse three level VSC and Type-1 controller to regulate the reactive current or the bus voltage. The performance is evaluated by transient simulation. It is observed that, the STATCOM shows excellent transient response to step change in the reactive current reference. While the eigenvalue analysis is based on D-Q model, the transient simulation is based on both D-Q and 3 phase models of STATCOM (which considers switching action of VSC).

• ETRI Journal
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• v.31 no.5
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• pp.565-575
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• 2009

This paper concerns the use of support vector regression (SVR), which is based on the kernel method for learning from examples, in identification of walking robots. To handle complex dynamics in humanoid robot and realize stable walking, this paper develops and implements two types of reference natural motions for a humanoid, namely, walking trajectories on a flat floor and on an ascending slope. Next, SVR is applied to model stable walking motions by considering these actual motions. Three kinds of kernels, namely, linear, polynomial, and radial basis function (RBF), are considered, and the results from these kernels are compared and evaluated. The results show that the SVR approach works well, and SVR with the RBF kernel function provides the best performance. Plus, it can be effectively applied to model and control a practical biped walking robot.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1883-1887
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• 1991

Identification theory for linear discrete system has been presented by a great many reference, but research works for identification of continuous-time system are less than preceding identification. In fact, a great man), systems for engineering are continuous-time systems, hence, research for identification of continuous-time system has important meaning. This paper offers the following results: 1. Corresponding relations for the parameters of continuous-time model and discrete model may be shown, when single input-output system has general characteristic roots. 2. To do identification of single variable continuity linear system with stability constraints from samples of input-output data, it is necessary to use optimization with stability constraints. 3. Main results of this paper may be explained by a simple example.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.51-56
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• 1998

In this paper, we analyze the effects of scaling factors on the performance of a fuzzy logic controller(FLC). The quantitative relation between input and output variables of FLC is obtained by using a qualsi-linear fuzzy model, and an approximate transfer function of FLC is dervied from the comparison of it with the conventional PID controller. Then we analyze in detail the effects of scaling factor using this approximate transfer function and root locus method. Also we suggest an on-line tuning method for scaling factors which employs an sample performance function and a variable reference for tuning index.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06b
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• pp.185-188
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• 2011

스마트폰의 대중화로 인해 사용자의 다양한 요구사항이 발생하고 있고, 스마트폰 용 어플리케이션에 대한 개발이 활발히 수행되고 있으나 하드웨어와의 밀접한 관계 및 재사용성의 요구를 반영하고 있지 못하므로 향후 수요를 감안하여 객체지향 개발방법론을 적용한 체계적인 접근이 필요하다. 본 논문에서는 대표적인 스마트폰 플랫폼인 안드로이드와 아이폰 플랫폼의 수명주기, 하드웨어, 어플리케이션 간의 관계를 통해 스마트폰 어플리케이션 개발절차를 도출하도록 시도하였으며, 객체지향 개발방법론 중에서 Reference Model 중심의 안드로이드 플랫폼과 Rich Client를 지원하는 아이폰 플랫폼에 각각 스마트폰 플랫폼에 준한 하드웨어 특성을 고려하여 특화된 CBD(Component Based Development)기반인 마르미-EM방법론과 서비스 기반의 어플리케이션을 지향하고 있는 MVC(Model-View-Control)패턴이 적용된 SaaS(Software-as-a-Service) 개발방법론을 적용하여 어플리케이션 개발 절차를 비교한다. 이를 통하여 개발방법론의 절차상의 차이점, 강점 및 보완 사항을 분석하고 방법론별 특징을 토대로 향후 보완점을 제안한다.

• Journal of Korean Library and Information Science Society
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• v.30 no.3
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• pp.97-116
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• 1999

The purpose of this paper is to develop a model of the strategic management of university library in Korea. The model from this study is summarized as follows: 1. External environment is divide into opportunities and threats. 2) Internal environment is divide into strengths and weakness. We can formulate a management strategy on the basis of library environment element from environment analysis and library situation. 2. Formulation of strategic management are formulated through three stages. 1) Library strategy: $\circled1$Growth strategy $\circled2$Stability $\circled3$Retrenchment 2) Business(competition) strategy 3) Functional strategy: $\circled1$Material organization strategy $\circled2$Collection strategy $\circled3$Reference service strategy $\circled4$Human resource management strategy $\circled5$marketing strategy 3. Implementation of strategic management 1) The chief of strategy implementation 2) Programs, budgets and procedures 3) Structure and strategy implementation 4) culture and strategy implementation 4. Evaluation and control of strategy implementation.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.426-429
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• 1989

The robust self-tuning controller is designed which is guaranteed the asymptotic regulation and tracking in the presence of a bounded parameter perturbation. The global stability in the presence of a finite noise and disturbance is ensured. The controller has a error driven structure, and involves the common model of a disturbance and reference input in the internal model. The adaptive system tunes the controller parameters such that the quadratic performance index which involves a weighting factor is optimized.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.85-86
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• 2006

In this paper, a nonlinear controller based on adaptive sliding-mode method which has a sliding surface vector including new boundary function is proposed and applied to a two-wheeled voiding mobile robot (WMR). This controller makes the welding point of WMR achieve tracking a reference point which is moving on a smooth curved welding path with a desired constant velocity. The mobile robot is considered in view of a kinematic model and a dynamic model in Cartesian coordinates. The proposed controller can overcome uncertainties and external disturbances by adaptive sliding-mode technique. To design the controller, the tracking error vector is defined, and then the new sliding is proposed to guarantee that the error vector converges to zero asymptotically. The stability of the dynamic system will be shown through the Lyapunov method. The simulations is shown to prove the effectiveness of the proposed controller.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.675-678
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• 1997

In this research we continue the study of nuclear power plant steam generator's intelligent modeling. This model represents the input-output behavior and is a preliminary stage for intelligent control. Among many intelligent models available, we study neural network models that have been proven as universal function approximators. We select multilayer perceptrons, circular backpropagation networks, piecewise linearly trained networks and recurrent neural networks as the candidates for the steam generator's intelligent models. We take the input-output pairs from steam generator's reference model and train the neural network models. We validate trained neural network models as intelligent models of steam generator.