• Proceedings of the KIEE Conference
• /
• 2005.04a
• /
• pp.280-282
• /
• 2005

This paper proposes a simple MPPT control scheme of a Current-Control-Loop Error system Based that can be obtains a lot of advantage to compare with another digital control method, P&O and IncCond algorithm, that is applied mostly a PV system. An existent method is needed an expensive processor such as DSP that calculated to change the measure power of a using current and voltage sensor at the once. Therefore, it is applied a small home power generation system that required many expenses. But, a proposed method is easy to solve the cost reduction and power unbalance problems that it is used by control scheme to limit error of a current control of common sensor. This proposed algorithm had verified through a simulation and an experiment on battery charger using PIC that is the microprocessor of a low price.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.7 no.4
• /
• pp.125-132
• /
• 1987

The bundle adjustment used in photogrammetric data reduction is based on the collinearity condition. Photogrammetry has been used in many non-topographic applications. Due to the necessities of having fiducial marks and knowing initial approximations for interior and exterior orientation elements in bundle adjustment, it cannot be applied when non-metric cameras are used. Marzan and Karara develop the DLT(Direct Linear Transformation) program which directly transforms comparator coordinates into object space coordinates without approximate values. In this paper, several modifications of original DLT program have been made for accuracy improvement in close-range photogrammetry using non-metric cameras. In modified program, gross error detection method and computation of exterior orientation elements are incorporated, and more iterations are introdued.

• Earthquakes and Structures
• /
• v.9 no.3
• /
• pp.455-480
• /
• 2015

In the last decade, displacement-based (DB) methods have become established design procedures for reinforced concrete (RC) structures. They use strain and displacement measures as seismic performance control parameters. As for other simplified seismic design methods, it is of great interest to prove if they are usually conservative in respect to more refined, nonlinear, time history analyses, and can estimate design parameters with acceptable accuracy. In this paper, the current Direct Displacement-Based Design (DDBD) procedure is evaluated for designing simple single degree of freedom (SDOF) systems with specific reference to simply supported RC bridge piers. Using different formulations proposed in literature for the equivalent viscous damping and spectrum reduction factor, a parametric study is carried out on a comprehensive set of SDOF systems, and an average error chart of the method is derived allowing prediction of the expected error for an ample range of design cases. Following the chart, it can be observed that, for the design of actual RC bridge piers, underestimation errors of the DDBD method are very low, while the overestimation range of the simplified displacement-based procedure is strongly dependent on design ductility.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.55 no.1
• /
• pp.33-38
• /
• 2006

This paper proposes a simple MPPT control scheme of a based Current-Control-Loop system that can be obtains a lot of advantage to compare with another digital control method, P&O(Perturbation and Observation) and IncCond(Incremental Conductance) algorithm, that is applied mostly a PV system. An existent method is needed an expensive processor such as DSP that calculated to change the measure power of a using current and voltage sensor at the once. Therefore, it is applied a small home power generation system that required many expenses. But, a proposed method is easy to solve the cost reduction and power unbalance Problems that it is used by control scheme to limit error of a current control of common sensor. This proposed algorithm had verified through a simulation and an experiment results on battery charger using PIC that is the microprocessor of a low price.

• Journal of Satellite, Information and Communications
• /
• v.9 no.4
• /
• pp.104-110
• /
• 2014

This paper considers two reconstruction schemes of structured-sparse signals, turbo inference and Markov chain Monte Carlo (MCMC) inference, in compressed sensing(CS) technique that is recently getting an important issue for an efficient video wireless transmission system using multi-copter as an unmanned aerial vehicle. Proposed reconstruction algorithms are setting importance on reduction of image data sizes, fast reconstruction speed and errorless reconstruction. As a result of experimentation with twenty kinds of images, we can find turbo reconstruction algorithm based on loopy belief propagation(BP) has more excellent performances than MCMC algorithm based on Gibbs sampling as aspects of average reconstruction computation time, normalized mean squared error(NMSE) values.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.20 no.4
• /
• pp.497-504
• /
• 2017

This paper proposes a method to measure the airburst height by utilizing a high speed camera. This method might be applied to the test of which flight target is alive after the burst. The proposed method consists of four main steps. The first step is to compute the impact point using the sea surface height. The second step is to compute the height of burst (HOB) by using the distance from the camera to the impact point. This could be different from the real explosion height. That is because the distance from the camera to the burst point is not the same as it from the camera to the impact point. Therefore, the third step is to calculate the approach angle of the flight target with respect to the installed camera. Then, the last step is to compensate the computed height by using the approach angle. The result of the proposed method is compared with it from the triangulation. In this paper, the HOB error is also analyzed regarding the approach angle difference. Based on this analysis, the camera position might be suggested for error reduction.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.11
• /
• pp.1645-1650
• /
• 2015

This paper presents the 3-dimensional electromagnetic field analysis method and correction of sensor distortion that is used by a motor speed sensor. The magnetic sensors are being expanded due to lower price than the other speed sensors such as resolver and encoder. Magnetic sensor generates sine and cosine waves when the motor rotates. However, the sine and cosine signals are distorted due to magnetic noise, which makes the angle error of the sensor, generated near by the Hall element. This paper defines an optimal design variables by using the Taguchi method to minimize output distortion of the magnetic sensor and permanent magnet. To enhance reliability of the magnetic position sensor from sensitivity error, assembly amplitude mismatch and the electrical angle, 3-Dimensional electromagnetic finite element method and correction algorithm errors were performed in due of the magnetic sensor in order to improve the quality of the initial production model.

• ETRI Journal
• /
• v.41 no.2
• /
• pp.235-241
• /
• 2019

In this paper, we propose a rank-weighted reconstruction feature to improve the robustness of a feed-forward deep neural network (FFDNN)-based acoustic model. In the FFDNN-based acoustic model, an input feature is constructed by vectorizing a submatrix that is created by slicing the feature vectors of frames within a context window. In this type of feature construction, the appropriate context window size is important because it determines the amount of trivial or discriminative information, such as redundancy, or temporal context of the input features. However, we ascertained whether a single parameter is sufficiently able to control the quantity of information. Therefore, we investigated the input feature construction from the perspectives of rank and nullity, and proposed a rank-weighted reconstruction feature herein, that allows for the retention of speech information components and the reduction in trivial components. The proposed method was evaluated in the TIMIT phone recognition and Wall Street Journal (WSJ) domains. The proposed method reduced the phone error rate of the TIMIT domain from 18.4% to 18.0%, and the word error rate of the WSJ domain from 4.70% to 4.43%.

• Journal of the Korean Society of Visualization
• /
• v.17 no.2
• /
• pp.48-57
• /
• 2019

A straightforward strategy for particle image velocimetry (PIV) interrogation and post-processing has been proposed, aiming at reducing errors and clarifying vortex structures. The interrogation window size should be kept small to reduce bias error and improve spatial resolution. A spatial filter is then applied to the velocity field to reduce random error and clarify flow structure. The performance of three popular spatial filters were assessed: box filter, median filter, and local quadratic polynomial regression filter. In order to quantify random uncertainty, the image matching (IM) method is applied to an experimental dataset of homogeneous and isotropic turbulence (HIT) obtained by 2D-PIV. We statistically analyze the uncertainty propagation through the spatial filters, and verify the reduction in random uncertainty. Moreover, we illustrate that the spatial filters help clarify vortex structures using vortex identification criteria. As a result, PIV random uncertainty was reduced and the vortex structures became clearer by spatial filtering.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.18 no.2
• /
• pp.27-37
• /
• 2022

In this paper, we presents a Multiple User Multiple Input Multiple Output (MU-MIMO) test-bed system for Time Division Duplex (TDD) Long Term Evolution-Advanced (LTE-A). Using two parameters, the condition number of the channel matrix and the path gain, the MU-MIMO system could switch pre-coder to maintain target Bit Error Rate (BER) level. This paper also introduces a calibration procedure for compensating error of Radio Frequency (RF) paths of the antennas and RF transceivers. From experimental measurements, dynamic pre-coding scheme could maintain target BER, set to 10^-3, with the pre-coder set configured with Zero Forcing (ZF), Tomlinson Harashima Pre-coding (THP), Lattice Reduction (LR). The simplest pre-coder ZF is adopted in stable channel, and when path gain become less than 0.25, LR is adopted. Lastly, when condition number of channel matrix become larger than 7, THP is adopted.