• 대한전자공학회논문지
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• 제25권6호
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• pp.700-709
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• 1988

A new technique is proposed for switch-level logic simulation for NMOS and CMOS logic circuits. For the simple inverter the rise or fall delay time is approximated by a product of polynomials of the input waveform slope, the output loading capacitance and the device configuration ratio, the polynomial coefficients being so determined as to best fit the SPICE simuladtion results for a given fabrication process. This approach can easily and accurately be extened to the case of multiple input transitions. The simulation results show that proposed method can predict the delay times within 5% error and with a speed up by a factor of three orders of magnitude for several circuits tested, as compared with the SPICE simulation.

• 대한전자공학회논문지
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• 제24권4호
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• pp.701-707
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• 1987

This paper is concerned with an accurate delay time modling of the ED MOS logic gates and its application to the multiple delay logic simulator. The proposed delay model of the ED MOS logic gate takes account of the effects of not only the loading conditions but also the slope of the input waveform. Defining delay as the time spent by the current imbalance of the active inverter to charge and discharge the output load, with respect to physical reference levels, rise and fall model delay times are obtained in an explicit formulation, using optimally weighted imbalance currents at the end points of the voltage transition. A logic simulator which uses multiple rise/fall delays based on the model as decribed in the above has been developed. The new delay model and timing verification method are evaluated with repect to delay accuracy and execution time.

• 전자공학회논문지C
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• 제35C권7호
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• pp.59-68
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• 1998

This paper is to develop an algorithm for the unlimited korean speech synthesis. We present the results controlled of prosodic factors with isolated words as aynthesis basis unit int he time domain. With a new pitch-synchronous and parametric speech synthesis mehtod in the time domain here we mainly present the results of controlled prosody factors such a spitch periods, energy envelops and durations and the evaluaton of synthetic speech qualities. In the case of synthesis, it is possible ot synthesize connected words by controlling of a continuous unified prosody that makes to improve the naturalities. In the results of experiment, it also has been to be improved uncontinuities of pitch and zeroing of energy in the junction parts of speech waveforms. Specially it has been to be possible to synthesize speeches with unlimitted durations and tones. So on it makes the noisiness and the clearness better by improving the degradation effects from the phase distortion due to the discontinuities in the waveform connection parts.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.109-112
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• 2005

본 논문에서는 초기화 구간에서의 시간단축과 높은 암실 명암비를 얻을 수 있는 새로운 초기화 파형을 제시한다. 새로운 초기화 파형에서 첫 번째 subfield는 기존의 conventional 구동파형과 마찬가지로 초기화 구간에서 ramp-up구간과 ramp-down구간이 필요하지만, 두 번째 subfield부터는 단지 ramp-up구간만이 적용된다. 한 frame에 8개의 subfield를 적용할 경우, 기존의 구동파형의 배경광이 $0.40cd/m^2$로 측정되는 반면, 새로운 초기화파형을 패널에 적용할 경우 배경광이 측정되지 않는다. 이러하여 우리는 새로운 초기화파형에서 무한대의 암실 명암비를 얻을 수 있다. 또한 새로운 초기화파형에서는 ramp-down구간을 없앰으로써 첫 번째 subfield를 제외하고는 초기화 시간을 165us로 시간을 줄일 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.255-257
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• 1995

Many new electronic products are required to have a unity power factor and a distortion free input current waveform. In this parer, a high performance single phase AC/DC converter with input power factor correction is proposed. And each parameters are determined. Proposed control strategy has many advantages which include two Quadrants operation, simplified control circuit, high performance features and continuous Input current. The experimental results are included to verify the validity of this approach.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.296-298
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• 1995

This paper proposes a new filter topology that suppresses the high voltage gradient(dv/dt) in ac motor terminals. The high voltage gradient(dv/dt) causes over voltages on the motor windings, the degradation or motor insulation, and the bearing failure. Moreover surge voltage with high voltage gradient(dv/dt) in the PWM inverter red drive system where long line cables are required causes more serious problem to the motor. Thus, the most advisable method is attaching output filter to the inverter output terminals. The conventional output filters have several problems such as bulky size, difficulty or parameter tuning. The proposed filter can be relatively smaller than the conventional filters. By the proposed filter, the shaping or PWM waveform can considerably suppress high dv/dt in motor feeding cable from the inverter. The effectiveness or the proposed filter is compared with that or the conventional one and is verified by the computer simulation.

• 전기학회논문지
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• 제57권5호
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• pp.741-747
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• 2008

This paper proposes a new concept of IDSP(Intelligent Digital Switchgear Panel) which can solve the problem of the safety, the reliability and the convenience to correspond to the requirement of the general electric customer or electric power company under the ubiquitous-based home automation environments. By analyzing their requirement functions, a 32-bit micro processor is adopted as main controller to support the designed functions efficiently. The DSP-based single phase power management device is utilized to collect the electric power information and the ethernet convertor to communicate through internet among the IDSPs and the remote computer system. In the proposed IDSP, the several functions are implemented such as the earth leakage level display and waveform transmission, the electric fee display, the voltage management, the load management and the load control function. Finally, the prototype of the IDSP is made experimently based on the designed results, and then the effectiveness is verified by testing its basic functions.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1999년도 학술대회논문집-국제 전기방전 및 플라즈마 심포지엄 Proceedings of 1999 KIIEE Annual Conference-International Symposium of Electrical Discharge and Plasma
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• pp.279-284
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• 1999

Although the switched reluctance motor (SRM) has a several advantages such as simple magnetic structure, robustness, wide range of speed characteristics and simple driving, it has a considerable inherent torque ripple and speed variation duet to the driving characteristics of pulse current waveform and the nonlinear inductance profile. The high torque ripple and speed variation inhibits wide application. The minimization of the torque ripple is very important in high performance servo drive applications, which require smooth operation with minimum torque pulsations. This paper presents the new SRM torque modeling technique for the control of instantaneous torque. The SRM is modeled by the database of torque profiles for every small variation in currents and rotor angles, which is inferred from the several measured data by the adaptive neuro-fuzzy inference technique. Simulation results demonstrating the effectiveness of proposed torque modeling technique are presented.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2000년도 학술대회논문집
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• pp.219-224
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• 2000

This paper presents a ripple reduction of BLDC motor using TMS320F240. A fault of permanent magnet(PM) BLDC motor possible to miniaturization and high-output is to be difficult to reduce speed-ripple at low speed region. An existing solution is to be use of PWM waveform by PI control with computing control angle of 60$^{\circ}$. The new family of DSP controllers provides a single chip solution by integrating on-chip not only a high computational power but also, all the peripherals necessary for electric motor control. This paper gives an advanced solution of the SVPWM technique for the purpose of reducing control angel rather than 60$^{\circ}$. This technique gives an excellent speed ripple characteristic.

• 한국항해학회지
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• 제20권3호
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• pp.85-95
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• 1996

In the velocimeter, the ultrasonic pulse signal is used for measuring the profile velocity of moving targets distributed in space because of the merits of its high distance resolution and harmless affect to the human body. The velocity reading in conventional ultrasonic pulsed velocimeter depends on the wave pattern reflecting the spatial distribution of scatters and includes observational error due to the signal processing of analyzing pulse signal. In this paper, we evaluate an influence of the received waveform of pulsed signal on the velocity information by setting a model. Subsequently, in order to improve the distance resolution and to obtain precise velocity information without the influence of the spatial distribution of scatterers, we propose a new method for the analysis of Doppler pulsed signal, in which the pulsed signal is transformed into a phase function with local data. Finally, it is confirmed that the performance of the velocimeter is more improved in the proposed method than in the conventional one.