• Journal of applied mathematics & informatics
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• 제19권1_2호
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• pp.215-229
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• 2005

In this paper, constraint aggregation is combined with the adjoint and multiple shooting strategies for optimal control of differential algebraic equations (DAE) systems. The approach retains the inherent parallelism of the conventional multiple shooting method, while also being much more efficient for large scale problems. Constraint aggregation is employed to reduce the number of nonlinear continuity constraints in each multiple shooting interval, and its derivatives are computed by the adjoint DAE solver DASPKADJOINT together with ADIFOR and TAMC, the automatic differentiation software for forward and reverse mode, respectively. Numerical experiments demonstrate the effectiveness of the approach.

• 전기학회논문지
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• 제56권11호
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• pp.1988-1991
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• 2007

This study investigates the performances of the signaling techniques including differential signals for the power-distribution network(PDN)s with and without the slit, using a rigorous evaluation method 'Modal Analysis', validated by being compared to the FDTD simulation up to 5 GHz.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1769-1775
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• 2004

In presence of collision between two rigid bodies, they exhibit impulsive behavior to generate physically feasible state. When the frictional impulse is involved, collision resolution can not be easily made based on a simple Newton's law or Poisson's law, mainly due to possible change of collision mode during collision, For example, sliding may change to sticking, and then sliding resumes. We first examine two conventional methods: the method of mode evolution by differential equation, and the other by linear complementarity programming. Then, we propose a new method for mode evolution by solving only algebraic equations defining mode changes. Further, our method attains the original nonlinear impulse cone constraint. The numerical simulation will elucidate the advantage of the proposed method as an alternative to conventional ones.

• 전기학회논문지P
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• 제62권2호
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• pp.84-89
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• 2013

In this paper, we propose interface circuits for reducing power consumption and EMI when sequences of data from LCD controller to LCD driver IC by transmitting two bit data during one clock period. The proposed circuits are operated in current mode, which is different from conventional voltage-mode signaling techniques, and also employ threshold technique of Modified-LVDS(Low Voltage Differential Signaling) method. We have simulated the proposed circuits using H-SPICE tool for performance analysis of the proposed method. The simulation results show that the proposed circuits provide a faster transmission speed and stronger noise immunity than the conventional LVDS circuits. It might be suitable for the real-time transmission of huge image data in LCD system.

• Steel and Composite Structures
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• 제2권3호
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• pp.223-236
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• 2002

An analytical procedure based on the transfer matrix method to estimate not only the natural frequencies but also vibration mode shapes of the thin-walled members composed of interconnected cylindrical shell panels is presented. The transfer matrix is derived from the differential equations for the cylindrical shell panels. The point matrix relating the state vectors between consecutive shell panels are used to allow the transfer procedures over the cross section of the members. As a result, the interactions between the shell panels of the cross sections of the members can be considered. Although the transfer matrix method is naturally a solution procedure for the one-dimensional problems, this method is well applied to thin-walled members by introducing the trigonometric series into the governing equations of the problem. The natural frequencies and vibration mode shapes of the thin-walled members composed of number of interconnected cylindrical shell panels are observed in this analysis. In addition, the effects of the number of shell panels on the natural frequencies and vibration mode shapes are also examined.

• 한국통신학회논문지
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• 제13권2호
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• pp.149-159
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• 1988

本 論文에서는 모우드 파우어에 대한 結合 微分方程式 구하기 위하여 Fourier Transform이 使用되었고, phasor型態의 試圖解를 使用하여 세 개의 모우드 結合係數 方程式을 誘導하였다. 이 모우드 結合係數 理論은 다른著者들에 의해 제안된 理論을 包含한다. 또한 光源이 正弦函數에 의하여 變調되는 경우에도 이 式이 잘 適用됨을 알 수 있었다. 實驗에서 多 모우드 언덕型 屈折率 光纖維의 모우드 結合係數는 正弦函數로 變調된 光源을 使用함에 의하여 決定되었다.

• 전자공학회논문지S
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• 제35S권4호
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• pp.128-138
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• 1998

This paper describes a principle of the conducted noise separator which can separate the conducted noise to the common mode and differential mode(normal mode), and presents the transfer characteristics of the separator designed and manufactured. We separated the conducted noise generated from switched mode converter to the CM and DM conducted noise, and also analyzed the source and path of conducted noise in the converter by the conducted noise separator. Since we could easily get the characteristics of the CM and DM conducted noise by the separator, we could efficiently determine the contermeasures for the reduction of the conducted noise and establish the foundation of the systematic procedure for the design of low pass filter.

• Journal of Electrical Engineering and Technology
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• 제6권5호
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• pp.647-657
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• 2011

The present paper proposes a sliding mode control with fixed switching frequency for three-phase three-leg voltage source inverter based four-wire shunt active power filter. The aim is to improve phase current waveform, neutral current mitigation, and reactive power compensation in electric power distribution system. The performed sliding mode for active filter current control is formulated using elementary differential geometry. The discrete control vector is deduced from the sliding surface accessibility using the Lyapunov stability. The problem of the switching frequency is addressed by considering hysteresis comparators for the switched signals generation. Through this method, a variable hysteresis band has been established as a function of the sliding mode equivalent control and a predefined switching frequency in order to keep this band constant. The proposed control has been verified with computer simulation which showed satisfactory results.

• 한국정밀공학회지
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• 제15권11호
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• pp.172-179
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• 1998

This paper proposes an identification method for modes of a thin plate where multiple actuators and sensors are bonded. When a natural frequency of a mode is decoupled from all other natural frequencies, the mode can be identified separatedly with a bandpass filter. Since a thin plate has resonant peaks at natural frequencies, the bandpass filter can be designed to extract the signal of the mode to be identified. Parameters of the second order linear differential equation of the mode can be obtained to apply the Least square method to the extract the modal signal. The proposed identification method is applied to an all-clamped plate with two pairs of piezoelectric actuators and sensors. The outputs of the identified model match with the experimental data well.

• Journal of Positioning, Navigation, and Timing
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• 제11권4호
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• pp.239-244
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• 2022

R-Mode is terrestrial based Global Navigation Satellite System (GNSS) backup radio navigation technology which used existing maritime information service infrastructure. It has advantages on reduce the cost and reutilize the frequency resource. In this paper, we propose a method to develop a medium-frequency (MF) band R-Mode transmitting station by utilizing the currently operating Differential GNSS (DGNSS) reference station infrastructure. To this end, the considerations for co-operating the DGNSS reference station and the MF R-Mode transmitting station are analyzed. In this process, we also analyze what is necessary to configure the communication system as a navigation system for range measurement. Based on the analysis result, MF R-Mode transmitting station system is designed and architecture is proposed. The developed system is installed in the field, and the performance evaluation results is presented.