• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2104-2106
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• 1997

In order to develop the three phase GTO CSI with double recovery path of commutation energy by passive devices (LCD), we studied the clamping circuit to protect switching device and energy recovery circuit to recover absorbed energy of capacitor and DC inductor. In this paper, we investigated how DC input power is increased or decreased according to energy recovery path with or not in the three phase GTO current source inverter, we used a induction motor as inverter load, and controlled a induction motor with v/f constant control. Experimental results show that dissipated DC power is decreased in $9{\sim}14%$ by double recovery path. We also confirmed that the characteristics is met as compare simulation results with experimental results according to each frequency.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.1
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• pp.49-55
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• 1996

In this paper, the characteristics of a double-sided linear pulse motor (DLPM) with permanent magnet are analysed using the method which combined the coenergy method and the equivalent magnetic circuit method. In the process of computation, the magnetic material nonlinealities of the permanent magnet, the primary and the secondary core are interpolated by the cubic spline method. Then, the equivalent magnetic circuit modelled by the permeance method including airgap reluctance, which is a function of displacement, is obtained. The static thrust which is the derivative of coenergy is computed by Newton Raphson method at each dispacement. And, in order to investigate the characteristics of the DLPM, the thrust shows as a function of displacement, input current and air gap. The simulation resuls are compared with experimental ones obtained from the DLPM with 2 phase and 4 poles.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.6
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• pp.24-29
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• 1976

A study is presented on the DDM (double delta modulation) system which incorporates another modulation loop in front of the delta modulation system. DDM is proposed to delta modulate the error signal which is derivated through the ordinary delta modulation. This system is constructed simply by adding a differential amplifier and an integrator to the basic DM system. Since signal-to-quantization noise ratio SNR is the most informative measure of quantizer performance, the formula of the max. SNR of the DDM system is derived and investigated experimentally for a sinusoidal input. The max. SNR of the DDM is larger than that of DM in low bit rate region and vice versa in high bit rate region.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.435-437
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• 1997

In order to develop the three phase GTO CSI with double recovery path of commutation energy by passive devices (LCD), we studied the clamping circuit to protect switching device and energy recovery circuit to recover absorbed energy of capacitor and DC link inductor. In this paper, we investigated how DC input power is increased or decreased according to energy recovery path with or not in the three phase GTO current source inverter. We used a induction motor as the load of inverter, and controlled a induction motor with V/F constant control. Experimental results show that dissipated DC power is decreased and capacitor voltage Vc is effectively suppressed by double recovery path.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.325-329
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• 2011

This paper introduces the 10b 1MS/s SAR ADC with double sampling technique to reduce the power consumption. The SAR ADC is implemented in CMOS 1P8M 65nm technology and occupies 0.11um2. The maximum sampling rate is 1MS/s. The simulated SNDR and SFDR are 55.6dB and 62.7dB at 484kHz input frequency, respectively. The implemented data converter consumes 507uW with 1.2-V supply.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.652-659
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• 2014

This paper deals with characteristic analysis of double sided permanent magnet linear generator using analytical method. We derived magnetic field solutions produced by permanent magnet and armature reaction based on the 2D polar coordinate and magnetic vector potential. based on the derived magnetic field solutions, Induced voltage is obtained when arbitrary sinusoidal input condition. In addition, electrical parameters such as back-EMF constant, resistance, and inductance are obtained. Finally, generating performance characteristic at the rated load and various load is examined by using equivalent circuit.

• Corrosion Science and Technology
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• v.20 no.5
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• pp.231-241
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• 2021

The objective of this study was to evaluate total current under steady-state conditions for a material undergoing corrosion using the electrochemical frequency modulation (EFM) technique, taking into account the presence of solution resistance and double layer capacitance. The analysis involving linearization of the Tafel curve allowed for the estimation of corrosion parameters. Results showed that the output signal was dependent on fundamental frequencies and their multiples. In addition, the output signal almost manifested itself at frequencies that were sums of fundamental frequencies of the applied sinusoidal signal. The harmonics calculated showed a significant shift from the principal frequency of input signals. The investigation involved the influence of corrosion current and anode-to-cathode Tafel slope ratio on faradaic and non-faradaic currents (including the average and RMS). The model presented showed both qualitative and quantitative improvements over the previously developed EFM technique that ignored the influence of solution resistance and the double layer capacitance while assuming the applied DC potential corresponded to the corrosion potential of the corroding material.

• Computers and Concrete
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• v.33 no.6
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• pp.739-754
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• 2024

This study presents an innovative AI-driven approach to assess the ultimate axial load in Double-Skinned Profiled Steel sheet Composite Walls (DPSCWs). Utilizing a dataset of 80 entries, seven input parameters were employed, and various AI techniques, including Linear Regression, Polynomial Regression, Support Vector Regression, Decision Tree Regression, Decision Tree with AdaBoost Regression, Random Forest Regression, Gradient Boost Regression Tree, Elastic Net Regression, Ridge Regression, and LASSO Regression, were evaluated. Decision Tree Regression and Random Forest Regression emerged as the most accurate models. The top three performing models were integrated into a hybrid approach, excelling in accurately estimating DPSCWs' ultimate axial load. This adaptable hybrid model outperforms traditional methods, reducing errors in complex scenarios. The validated Artificial Neural Network (ANN) model showcases less than 1% error, enhancing reliability. Correlation analysis highlights robust predictions, emphasizing the importance of steel sheet thickness. The study contributes insights for predicting DPSCW strength in civil engineering, suggesting optimization and database expansion. The research advances precise load capacity estimation, empowering engineers to enhance construction safety and explore further machine learning applications in structural engineering.

• The Journal of the Acoustical Society of Korea
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• v.39 no.5
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• pp.476-482
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• 2020

Sequence-to-sequence deep neural networks with attention mechanisms have shown superior performance across various domains, where the sizes of the input and the output sequences may differ. However, if the input sequences are much longer than the output sequences, and the characteristic of the input sequence changes within a single output token, the conventional attention mechanisms are inappropriate, because only a single context vector is used for each output token. In this paper, we propose a double-attention mechanism to handle this problem by using two context vectors that cover the left and the right parts of the input focus separately. The effectiveness of the proposed method is evaluated using speech recognition experiments on the TIMIT corpus.

• Journal of IKEEE
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• v.18 no.2
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• pp.192-197
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• 2014

In this paper, $3^{rd}$ SDM with FDPA(Feedback Delay Pass Addition) technique to improve the input range is proposed. Conventional architecture with $3^{rd}$ transfer function is just made as adding a digital delay path in $2^{nd}$ SDM architecture. But the input range is very small because feedback path into the first integrator is increased. But, proposed architecture change feedback path into the first integrator to the second integrator, so input range could be improved about 9dB. The $3^{rd}$ SC SDM with only one operational amplifier was implemented using double-sampling technique. Simulation results for the proposed SDM designed in $0.18{\mu}m$ CMOS technology with power supply voltage 1.8V, signal bandwidth 20KHz and audible sampling frequency 2.8224MHz show SNR(Signal to Noise Ratio) of 83.8dB, the power consumption of $700{\mu}W$ and Dynamic Range of 82.8dB.