• International Journal of Aeronautical and Space Sciences
• /
• v.17 no.2
• /
• pp.214-221
• /
• 2016

An attitude estimation algorithm which integrates gyroscope and vision measurements using an adaptive complementary filter is proposed in this paper. In order to make the filter more tolerant to vision measurement fault and more robust to system dynamics, fuzzy interpolator is applied. For recognizing the dynamic condition of the system and vision measurement fault, the cut-off frequency of the complementary filter is determined adaptively by using the fuzzy logic with designed membership functions. The performance of the proposed algorithm is evaluated by experiments and it is confirmed that proposed algorithm works well in the static or dynamic condition.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.14 no.1
• /
• pp.11-21
• /
• 1989

In this paper, a GMSK modulator was implemented with a gaussian lowpass filter using digital signal processing, a phase integration, D/A convers and auxiliary circuits. The relatively narrow bandwidth of power spectrum of the GMSK modulator is observed when the cut off frequency (B T) of the gaussian baseband filter is varied. In a demodulator, a discriminator type circuit is used. Using the above degital radio GMSK modem, BER is theoretically derived and experimentally measured when 16Kbps PRBS data is transmitted under Rayleigh fading and additive white gaussian noise conditions.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.55 no.8
• /
• pp.430-435
• /
• 2006

This paper presents a method about the efficiency analysis and the harmonic reduction of single phase NPC multi-level inverter with LC-trap filter and LCR output filter. The proposed LC-trap filter is comprised of a conventional LC output filter, by using LC-trap filter the need for high damping resistor and low LC cut-off frequency is eliminated. Also, low damping resistor is increased the efficiency of the output filter. Experimental verification of the proposed circuit is provided with single phase NPC multilevel inverter system and DSP controller.

• Proceedings of the KIEE Conference
• /
• 1999.07e
• /
• pp.2136-2138
• /
• 1999

In this study, we describe the change of electrical properties of XLPE with electrical-tree degradation. XLPE insulation was used as specimen which was cut off from 22.9kV XLPE insulated cable and made in a type of block. The applying voltages are 8kV, 10kV, 12kV and frequency is 60Hz Ogra needles having tip radius of 10$\mu\textrm{m}$ were inserted in blocks. PD quantity and $tan{\delta}$ and DC current were measured from inception of tree to breakdown and their characteristics were analyzed.

• Proceedings of the KIEE Conference
• /
• 1999.07e
• /
• pp.2161-2163
• /
• 1999

Generally, ZnO varistors have dynamic characteristics that the cut-off voltage increases as the time to crest of the varistor current decreases. Dynamic characteristics of ZnO varistor are the most important factor in region of the steep front discharge current particularly. Also, V-I characteristics of ZnO varistor have hysterisis loop in time domain and frequency dependency. This paper deals with ZnO varistor numerical equation and modeling method which takes the behavior of varying clamping voltage into consideration during the time to crest, in range of $1{\mu}m{\sim}50{\mu}m$, of impulse current applied to a ZnO varistor. The simulated results by the proposed model are compared with experimental results for each of the impulse current.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.27 no.1
• /
• pp.51-58
• /
• 1990

NPN Si bipolar transistors with two different emitter widths are designed and fabricated. The effects of the emitter width on the small signal parameters of BJTs are measured and discussed. A new ac method for determining the current gain, the cut off frequency and the internal capacitances from the input impedance circle characteristics as a function of the varied external series resistances is presented. This method allows an accurate characterization of bipolar transistors with high current gain. The variation of the I-V curves of the emitter junction with the reverse collector junction voltages is discussed from the changes in the intsrinsic base resistances.

• Journal of the Korean Data and Information Science Society
• /
• v.16 no.2
• /
• pp.477-505
• /
• 2005

This paper gives a computer code that gives p-value's for Kendall's Tau table. The code centers around finding the cumulative frequency of a given Sigma value. Current tables usually give critical values for given cut-off percentages. For small sample sizes the critical values may be inexact, and for large samples the values are not be published. SPSS has a built in function for finding the Kendall rank correlation, but the output does not include the Sigma value. Before the code is given, this paper will concentrate around how to find the Sigma value, and the related tau statistic. The computer code is written in MATLAB, but the ideas can be easily transferred to different languages.

• Journal of Navigation and Port Research
• /
• v.28 no.8
• /
• pp.667-671
• /
• 2004

This paper describes an development of digital power supply for ship's emergency lighting system(SELS). Proposed system is composed of emergency power supply system(EPSS), half bridge(HB) inverter, fluorescent lamp(FL) starting circuit and microprocessor control system. Experimental works using proposed system confirm that speedy and stable power to be supplied when main power source cut-off, compared with conventional analog type, and control input power up to 35.0［%］ by adjusting pulse frequency of the HB inverter.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.104-106
• /
• 2003

This paper proposes a parameter estimation technique of a power transformer. Based on the combined equation, it estimates separately the primary and secondary leakage inductances using the least square method from the instantaneous voltages and currents in the steady state. The performance of the proposed technique was investigated by varying the cut-off frequency of the filter and the number of samples per cycle. The estimated values are obtained based on the average value for 41 cycles.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.584-586
• /
• 2005

The stroke of piston in the linear compressor driven by LPMSM can be obtained from integrating the input voltage and current of LPMSM, and may be diverged due to dc components In the voltage and current. The strategy to prevent the divergence of stroke using both the high-pass filter and dc offset compensation was suggested. The equations for the magnitude and phase of the stroke and also dc offset including the stroke are derived as a function of the cut-off frequency of HPF. The performance of stroke calculation scheme has been verified by experimentally on a linear compressor drive system, where the control was implemented by a 16-bit DSP.