• Proceedings of the Korea Multimedia Society Conference
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• 2012.05a
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• pp.343-344
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• 2012

With the increase of sensitive data and their secure transmission and storage, the use of encryption techniques has become widespread. The performance of encoding majorly depends on the computational time, so a system with less computational time suits more appropriate as compared to its contrary part. Double Random Phase Encoding (DRPE) is an algorithm with many sub functions which consumes more time when executed serially; the computation time can be significantly reduced by implementing important functions in a parallel fashion on Graphics Processing Unit (GPU). Computing convolution using Fast Fourier transform in DRPE is the most important part of the algorithm and it is shown in the paper that by performing this portion in GPU reduced the execution time of the process by substantial amount and can be compared with MATALB for performance analysis. NVIDIA graphic card GeForce 310 is used with CUDA C as a programming language.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1648-1654
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• 2016

This paper analyzes complex vector current control for the enhanced cross-coupling compensation in accordance with parameter variation in grid-connected inverter system, and verifies through simulation and experiment. Complex vector current control is performed in the synchronous reference frame through d-q transformation. It generates cross-coupling components with rotating nominal angular frequency. In general, cross-coupling elements are compensated by decoupling terms added to output of conventional decoupling PI controller. But, it is impossible to compensate them perfectly which transient response is especially deteriorated such as large overshoot and slow tracking, when variation of grid impedance or measurement error occurs. However, complex vector current control can improve stability and response characteristic of current control regardless of the situation as before. Decoupling controller and complex vector controller are represented through complex forms, and these controllers are analyzed by using frequency response in s-domain, respectively. It is verified that complex vector controller has more superior response characteristic than decoupling controller through MATALB, PSIM and experimental in 5kW grid-connected inverter when L filter parameter is varied from 1.1mH to increase double, 2.2mH.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.530-543
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• 2013

This paper describes a control scheme of speed sensorless fuzzy direct torque control (FDTC) of permanent magnet synchronous motor for electric vehicle (EV). Electric vehicle requires fast torque response and high efficiency of the drive. Speed sensorless FDTC In-wheel PMSM drives without mechanical speed sensors at the motor shaft have the attractions of low cost, quick response and high reliability in electric vehicle application. This paper presents a new approach to estimate the speed of in-wheel electrical vehicles based on Model Reference Adaptive System (MRAS). The direct torque control suffers in low speeds due to the effect of changes in stator resistance on the flux measurements. To improve the system performance at low speeds, a PI-fuzzy resistance estimator is proposed to eliminate the error due to changes in stator resistance. High performance sensorless drive of the in-wheel motor based on MRAS with on line stator resistance tuning is established for four motorized wheels electric vehicle and the whole system is simulated by matalb/simulink. The simulation results show the effectiveness of the new control strategy. This proposed control strategy is extensively used in electric vehicle application.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9C
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• pp.748-755
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• 2010

In this paper we propose an improved face recognition method using Gabor tensor. Gabor transform is known to be able to represent characteristic feature in face and reduced environmental influence. It may contribute to improve face recognition ratio. We attempted to combine three-dimensional tensor from Gabor transform with MPCA(Multilinear PCA) and LDA. MPCA with tensor which use various features is more effective than traditional one or two dimensional PCA. It is known to be robust to the change of face expression or light. Proposed method is simulated by MATALB9 using ORL and Yale face database. Test result shows that recognition ratio is improved maximum 9~27% compared with exisisting face recognition method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.301-304
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• 2006

As is different from formerly used fixing camera method in this paper, proposed method that can measure the speed of vehicles and logarithm of vehicles in video. Vehicles that proposed method runs with 50km/h, 80km/h, 90km/h's the speed recording on Video Tape beginning point and time of reaching point draw, and calculated 47.57km/h, 81.20km/h, the 90.00km/h speed by time and distance, the tracking cars and the velocity detection in video with the 'begin-line mark' and the 'end-line mark' processing.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.453-461
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• 2018

Shaft stations of underground uranium mines in China are not only utilized as waiting space for loaded mine-cars queuing to be hoisted but also as the principal channel for fresh air taken to working places. Therefore, assessment of how mine-car queuing processes affect shaft station radon concentration was carried out. Queuing network of mine-cars has been analyzed in an underground uranium mine, located in Quzhou, Zhejiang province of Eastern China. On the basis of mathematical analysis of the queue network, a MATLAB-based quasi-random number generating program utilizing Monte-Carlo methods was worked out. Extensive simulations were then implemented via MATALB operating on a DELL PC. Thereafter, theoretical calculations and field measurements of shaft station radon concentrations for several working conditions were performed. The queuing performance measures of interest, like average queuing length and waiting time, were found to be significantly affected by the utilization rate (positively correlated). However, even with respect to the "worst case", the shaft station radon concentration was always lower than $200Bq/m^3$. The model predictions were compared with the measuring results, and a satisfactory agreement was noted. Under current working conditions, queuing-induced variations of shaft station radon concentration of the study mine are not remarkable.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.997-1004
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• 2007

High resolution synthetic aperture radar image could be sensitive to the various parameters of the payload, platform, and ground system. In this paper, a parameter based SAR simulator is presented for two-dimensional image formation and image quality analysis. Functional modules are implemented by Matalb code and GUI for the flexibility and expandability. Main function of this simulator includes the SAR input signal generation, range-doppler algorithm(RDA) based SAR image formation, and the SAR image quality analysis which is relevant to the SAR system design parameters. This simulator can effectively be used for the SAR image quality performance evaluation, which can be applicable to the airborne as well as spaceborne SAR system design and analysis.

• Journal of the Korea Institute of Building Construction
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• v.19 no.1
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• pp.39-46
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• 2019

A three-dimensional flow simulation model for high flow concrete was developed using Incompressible Smoothed Particle Hydrodynamics (ISPH), which can solved Navier-Stokes equation with the assumption of a fluid to be incompressible. For the simulation, a computer program code for ISPH was implemented with MATALB programming code. A piecewise cubic spline function was used for the kernel function of ISPH. Projetion method was used to calculate the velocity and pressure of particles as a function of time. Fixed ghost particle was used for wall boundary condition. Free surface boundaries were determined by using virtual density of particles. In order to validate the model and the code, the simulation results of slump flow test, $T_{500}$ test and L-box test were compared with experimental ones. The simulation results were well matched with the experimental results. The simulation described successfully the characteristics of the flow phenomenon according to the change of the viscosity and yield stress of high flow concrete.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.6
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• pp.415-422
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• 2010

Development of the reliability-based design program in the GUI environment is inadequate for engineers familiar with the deterministic design to deal with the international design criterion based on the probabilistic design. In this study, the design program based on the GUI environment is developed in order to more efficiently input the design factor and more easily carry out the design works. The GUI environment is the GUIDE (Graphic User Interface Development Environment) tool supported by the latest MATALB version 7.1. In order to test the model reliability, the probabilities of failure (POF) on the breakwater armor block (AB) and gravity quay-wall (QW) in the sliding mode are computed using the model in the Level II and Level III. The POF are 55.4~55.7% for breakwater AB and 0.0006~0.0007% for gravity QW. A non-GUI environment program results of the POF are 55.6% for breakwater AB and 0.0018% for gravity QW. In comparison, the POF difference is negligible for breakwater AB because the exact input design parameters are available, whereas the large POF difference, but within the same order, for gravity QW can be explained by the difference of the input design factors because of the poor input data information.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.453-458
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• 2019

In this study we analyzed the tendency of the image characteristic by changing filtering factor for the proposed fast non local means (FNLM) noise reduction algorithm with designed Male Adult mesh (MASH) phantom through Geant4 application for tomographic emission (GATE) simulation program. To accomplish this purpose, MASH phantom for human copy was designed through the GATE simulation program. In addition, we acquired degraded image by adding Gaussian noise with a value of 0.005 using the MATALB program in MASH phantom. Moreover, in degraded image, the FNLM noise reduction algorithm was applied by changing the filtering factors, which set to 0.005, 0.01, 0.05, 0.1, 0.5, and 1.0 value, respectively. To quantitatively evaluate, the coefficient of variation (COV), signal to noise ratio (SNR), and contrast to noise ratio (CNR) were calculated in reconstructed images. Results of the COV, SNR and CNR were most improved in image with a filtering factor of 0.05 value. Especially, the COV was decreased with increasing filtering factor, and showed nearly constant values after 0.05 value of the filtering factor. In addition, SNR and CNR were showed that improvement with increasing filtering factor, and deterioration after 0.05 value of the filtering factor. In conclusion, we demonstrated the significance of setting the filtering factor when applying the FNLM noise reduction algorithm in degraded image.