• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1740-1741
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• 2011

This paper proposes a new linear recursive target state estimator for automotive collision warning system. The target motion is modeled in Cartesian coordinate system while the radar measurements such as range, line-of-sight angle and range rate are obtained in polar coordinate system. To solve the problem by nonlinear relation between these two coordinate system, a practical linear filter design scheme employing the predicted line-of-sight Cartesian coordinate system (PLCCS) is proposed. Especially, PLCCS can effectively incorporate range rate measurements into target tracking system. It is known that the utilization of range rate measurements enables the improvement of target tracking performance. Moreover, PLCCS based target tracking system is implemented by linear recursive filter structure and hence is more suitable scheme for the development of reliable collision warning system. The performance of the proposed method is demonstrated by computer simulations.

• Journal of the Korean Vacuum Society
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• v.8 no.3B
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• pp.353-360
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• 1999

The global balance model is applied to investigate the transient behavior of the electron density and temperature in helicon plasmas. The power absorption calculated from the solutions of the Maxwell equations is used in solving the power balance equation. A balance model for the neutral gas is also considered to fins its density self-consistently. It is turned out that the numerical results reasonably explain consequences of the ion pumping effect including the occurrence of two distinct modes of pulsed helicon discharge which have been observed experimentally. The behavior of the discharge parameters are fond to be primarily dependent on the power absorption and the gas flow rate, but the pressure controls the electron density and temperature of the final steady state as well as the transient state even with the same flow rate. Finally, it is shown that the electron density virtually the linear relationship between the density and the magnetic field is retained for a higher pressure when the effect of the ion pumping is negligible.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.36-42
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• 1998

In this study, active muffler was designed and was manufactured for exhaust noise reduction of commercial vehicle, then experiment of real vehicle was conducted. In a manufactured active muffler, because the flow of exhaust noise in tail pope outlet are become a plane wave, the global reduction if radiation noise from outlet and the placement of error microphone to avoid the exhaust gas of high temperature could be implemented. In control algorithm, reduction of noise of engine driving frequency and harmonic frequency can be archieved using proposed reference signal including a fixed speed state(2,000rpm, 3,000rpm, 4,000rpm) and a run-up speed state(2,000rpm$\rightarrow$4,000rpm) is accomplished with the active muffler installed in vehicle.

• Earthquakes and Structures
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• v.6 no.1
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• pp.45-69
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• 2014

The 2009 L'Aquila, Italy earthquake shook a high density area causing a wide spectrum of damage to reinforced concrete with infill buildings, one of the most common building types used in Italy. The earthquake has proven to be a "full-scale" laboratory to further understand building performance. This paper presents the first results of a joint research effort between the University of Bologna and Degenkolb Engineers, aimed at investigating the seismic behavior of an infilled frame building that collapsed during the earthquake. State-of-the-practice techniques were implemented as a way to determine the reliability of these modeling techniques in anticipating the observed building performance. The main results indicate that: (i) the state-of-the-practice techniques are able to predict the observed behavior of the buildings; (ii) the masonry infills have a great influence on the behavior of the building in terms of stiffness, strength and global ductility.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.10
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• pp.1498-1506
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• 1989

A new stabilization scheme is proposed in which the local state feedback is utilized in each decentralized controller for large-scale interconnected systems. In the proposed scheme, the controller is designed in two steps. First, the feedback gain of each decentralized controller is temporarily chosen so that the eigenvalues of each isolated subsystem are placed at the desired locations in the complex plane. Secondly, the feedback gain of each controller is compensated so that the time derivative of the Lyapunov function candidate for the overall closed-loop system should be negative. A sufficient condition which assures the global system to stable is given.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.344-348
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• 1992

This paper describes a procedure to design a hovering flight controller for a model helicopter using LQG theory. Parameters of the model helicopter in hover are obtained using direct measurements and calculations proposed by other research. A feedback co is by using digital LQG theory. First, a full state feedback controller is designed to the discretized system taking desirable transient response and other assumptions into account. Then a full-state estimator is designed and revised until desirable response is obtained while global stability is maintained. Performance of the controller is tested by computer simulations. Experiments have been performed using a 3-degree-of-freedom gimbal that holds the model helicopter, and the controller exhibited stable hover capability.

• School Mathematics
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• v.4 no.1
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• pp.63-78
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• 2002

This research's purpose is to investigate follows. 1. How do middle school teachers recognize the mathematical communication globally? 2. If we classify the modes of mathematical communication as written, spoken, graphic and active ones, how much do teachers use them and how do the students' communication ability come as teachers judge? 3. What are teachers' thinking, the present condition and the future indication for the application of mathematical communication with computer? 4. Do teachers evaluate their students' communication ability? If then, what is the assessment rubric of student's communication ability? The results are analyzed by frequency analysis including percentile and free writings are arranged by similar responses. The result of this study is that global recognition for mathematical communication, current state for students' concrete performance of mathematical communication, and assessment of mathematical communication & proposals are very lacking.

• Asian review of World Histories
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• v.3 no.1
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• pp.113-135
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• 2015

The word 'urbanity' literally means 'quality or state of being urban' where the criterion of urban economic and civic culture is assumed despite the general celebration of cultural uniqueness of urban centers. The narratives celebrating the uniqueness of urban centers since the ancient past till recent times could not get rid of the broad categorization of the urban models depending on their contextual networks of trade, mobility and culture. This paper attempts to explore whether the urban cultures in South Asia even preceding a global phenomenon like colonialism were actually reflecting an idea of urbanity where the urban culture, including planning and architecture reflected a trans-national model. This paper particularly concentrates on the medieval period when a pattern of urbanity took shape in this subcontinent under the influence of Islam, which could be explained by its particular idea of urban model, cultural exchange and vibrant trade networks.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.77-78
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• 2006

Post industrial technologies have improved human standard of living, however, a host of negative environmental consequences from the unlimited industrial appetite have posed serious global challenges. Remanufacturing is an industrial manufacturing process that is to restore old products to perform like a new and to save energy, natural resources, landfill space and to reduce air pollution by less re-smelting. By extending product life cycle, remanufacturing gives us enormous opportunities for sustainable development of our society. This paper introduces current state of the art and future perspective in the field of automotive remanufacturing focusing on alternator and start motor. The results could be used as a basic information for further remanufacturing applications in Korea.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1471-1474
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• 2002

In this paper, we propose a robust indirect adaptive fuzzy state feedback regulator based on Takagi-Sugeno fuzzy model. The proposed adaptive fuzzy regulator is less sensitive to singularity than the conventional one based on the feedback linearization method. Furthermore, the proposed control method is applicable to not only plants with a perfect model but also plants with an imperfect model, which causes uncertainties. We verify the global stability of the proposed method by using Lyapunov method. In order to support the achievement, the application of the proposed adaptive fuzzy regulator to the control of a nonlinear system under the external disturbance is presented and the performance was verified by some simulation result.