• Korean Journal of Computational Design and Engineering
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• v.5 no.2
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• pp.155-167
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• 2000

To be presented is two-dimensional chip-load analysis for cutting-load smoothing which is needed in unmanned machining and high speed machining of sculptured surfaces. Cutter-engagement angle and effective cutting depth are defined as chip-loads which are the geometrical measures corresponding to cutting-load while machining. The extreme values of chip-loads are geometrically derived in the line-line and line-arc-line blocks of the two-dimensional NC-codes. AFA(automatic feedrate adjustment) strategy for cutting-load smoothing is presented based on the chip-load trajectories.

• Journal of applied mathematics & informatics
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• v.29 no.5_6
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• pp.1511-1523
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• 2011

In this paper, we consider the smoothing Newton method for the nonlinear complementarity problems with $P_0$-function. The proposed algorithm is based on a new smoothing function and it needs only to solve one linear system of equations and perform one line search per iteration. Under the condition that the solution set is nonempty and bounded, the proposed algorithm is proved to be convergent globally. Furthermore, the local superlinearly(quadratic) convergence is established under suitable conditions. Preliminary numerical results show that the proposed algorithm is very promising.

• Proceedings of the Korea Water Resources Association Conference
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• 2003.05b
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• pp.627-630
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• 2003

• Journal of Power Electronics
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• v.9 no.2
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• pp.320-333
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• 2009

A Photovoltaic (PV) system's power output varies with the change of climate. Frequency deviations, tie line voltage swings are caused by the varying PV power when large PV power from several PV systems is fed in the utility. In this paper, to overcome these problems, a simple coordinated control method for smoothing the variations of combined PV power from multiple PV systems is proposed. Here, output power command is formed in two steps: central and local. Fuzzy control is used to produce the central smoothing output power command considering insolation, variance of insolation and absolute average of frequency deviation. In local step, a simple coordination is kept between the central power command and the local power commands by producing a common tuning factor. Power converters are used to achieve the same output power as local command power employing PI control law for each of the PV generation systems. The proposed method is compared with the method where conventional Maximum Power Point Tracking (MPPT) control is used for each of the PV systems. Simulation results show that the proposed method is effective for smoothing the output power variations and feasible to reduce the frequency deviations of the power utility.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.939-948
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• 1999

주문형 비디오나 원격 회의 그리고 원격 강의와 같은 멀티미디어 애플리케이션들은 비디오나 오디오와 같은 멀티미디어 트래픽을 유발한다. 이러한 멀티미디어 트래픽의 가장 큰 특성은 폭주성이다. 폭주성은 통신망의 효율을 떨어뜨리는 매우 중요한 요인이며, 따라서 폭주성에 대처할 수 있는 효율적인 대역폭 할당 정책이 통신망 관리에서 매우 중요하다. 본 논문에서는 멀티캐스팅 방식의 온라인 비디오 애플리케이션에 대해서 대역폭 완화 작업이라고 불리우는 효율적이고 유용한 대역폭 할당 방안을 설계하였다. 본 논문에서 제시하는 새로운 대역폭 완화 기법은 비디오 서버에서 이미 전송된 데이타의 특성을 이용하여 대역폭 완화창의 크기를 조절하는 동적인 기법이다. 몇 가지 MPEG 트레이스들로 실험했을 때 기존의 온라인 대역폭 완화 기법과 비슷한 성능을 보이고, 특히 멀티캐스팅 방식의 온라인 비디오 서비스에 대해서는 서버의 자원 효율성을 향상시킴을 알 수 있었다. Abstract All of the multimedia applications such as VOD, teleconferencing, and tele-lecturing invoke multimedia traffic like video or audio traffic. The most important characteristic of these multimedia traffic is the burstiness property. So, bandwidth management is becoming the major part of network management. In this paper, we propose a new and efficient bandwidth management technique called bandwidth smoothing for the multicasting on-line video applications. Our bandwidth smoothing technique reduces as much of the network bandwidth required to transmit on-line video traffic as previously proposed methods, and improves the server's resource utilization especially for the multicast on-line video services.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.54 no.3
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• pp.111-118
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• 2005

Since the residential load is an AC load and the output of solar cell is DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation, it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper, DC/AC converter is three phase PWM converter with smoothing reactor. And then, feed-forward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.

• Journal of applied mathematics & informatics
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• v.29 no.3_4
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• pp.653-668
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• 2011

This paper presents a new hybrid method for solving nonlinear complementarity problems with $P_0$-functions. It can be regarded as a combination of smoothing trust region method with ODE-based method and line search technique. A feature of the proposed method is that at each iteration, a linear system is only solved once to obtain a trial step, thus avoiding solving a trust region subproblem. Another is that when a trial step is not accepted, the method does not resolve the linear system but generates an iterative point whose step-length is defined by a line search. Under some conditions, the method is proven to be globally and superlinearly convergent. Preliminary numerical results indicate that the proposed method is promising.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.262-265
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• 2012

In this paper we propose a new deinterlacing method with block classification and motion vector smoothing. The proposed method classifies a block, then depending on the region it belongs to, the motion estimation or line averaging is applied. To classify a block its variance is calculated. Then, for those blocks that belong to simple non-texture region the line averaging is done while motion estimation is applied to complex region. The motion vector field is smoothed using median filter what yields more accurate interpolation. In the experiments for the subjective evaluation, the proposed method bas shown satisfying results in terms of computation time consumption and peak signal-to-noise ratio. Due to the simplicity of the algorithm computation time was drastically decreased.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.2
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• pp.94-98
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• 2011

Electrolytic power capacitors today form essential components for virtually any power electronic system such as DC/DC converter or UPS. Frequently, electrolytic capacitors for DC link voltage smoothing are the key components which determine the life cycle of the whole unit and often are responsible for converter breakdown failures. In this paper, ethernet-based remote diagnosis system for DC voltage smoothing capacitor using DSP control board is developed. To estimate the status of the capacitor, the equivalent series resistor(ESR) of the component has to be determined. The ESR detection scheme is based on the determination of the capacitor ripple power losses calculated from DC link voltage/current measurement. Experimental results show the veridity and reliability of the proposed ethernet-based remote on-line capacitor diagnosis system.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.4
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• pp.433-440
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• 2007

In this paper a new dynamoelectric winch system is introduced which is widely applied in shipping. building, architecture and so on. Generally in the winch system the squirrel cage induction motor is used as prime mover and line voltage is directly applied to the induction motor during operation. So it is difficult to obtain the smoothing revolution. because of variation of the weight of cargo and system operating method. Based on above reasons, the switched reluctance motor (SRM) is proposed to replace the induction motor because of more reliable mechanical structure, better traction characteristic and higher efficiency compared to induction motor. And in order to solve smoothing revolution problem, instantaneous torque control method based on torque sharing function (TSF) is used. Finally the validity of the proposed method is verified through the simulation and experimental results.