• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.7
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• pp.32-38
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• 2012

In this paper, to eliminate intersymbol interference of the received signal due to multipath propagation, a parallel equalization algorithm using two error estimation functions is proposed. In the proposed algorithm, multilevel two-dimensional signals are considered as equivalent binary signals, then error signals are estimated using the sigmoid nonlinearity effective at the initial phase equalization and threshold nonlinearity with high steady-state performance. The two errors are scaled by a weight depending on the relative accuracy of the two error estimations, then two filters are updated differentially. As a result, the combined output of two filters was to be the optimum value, fast convergence at initial stage of equalization and low steady-state error level were achieved at the same time thanks to the combining effect of two operation modes smoothly. Usefulness of the proposed algorithm was verified and compared with the conventional method through computer simulations.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.6
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• pp.16-25
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• 2009

In this paper we propose the block based image segmentation method using the cyclic properties of hue components in HSI color model. In proposed method we use center point instead of hue mean values as the hue representatives for regions in image segmentation considering hue cyclic properties and we also use directed distance for the hue difference among regions. Furthermore we devise the simple and effective method to get critical values through control parameter to reduce the complexity in the calculation of those in the conventional method. From the experimental results we found that the segmented regions in the proposed method is more natural than those in the conventional method especially in texture and red tone regions. In the simulation results the proposed method is better than the conventional methods in the in the evaluation of the human segmentation dataset presented Berkely Segmentation Database.

• Journal of the Korea Concrete Institute
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• v.23 no.6
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• pp.791-797
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• 2011

This paper presents the test results of 12 direct tensile specimens to investigate the effect of cover thickness on the tension stiffening behavior in axially loaded reinforced concrete tensile members. Six concrete cover thickness ratios are selected as a main experimental parameter. The results showed that, as cover thickness became thinner, more extensive split cracking along the reinforcement occurred and transverse crack spacing became smaller, making the effective tensile stiffness of thin specimens at the stabilized cracking stage to be much smaller than that of thick specimens. This observation is not implemented in the current design provisions, in which the significant reduction of tension stiffening effect can be achieved by applying thinner cover thickness. Based on the present results, a modified tension stiffening factor is proposed to account for the effect of the cover thickness.

• Journal of Ecology and Environment
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• v.43 no.4
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• pp.385-389
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• 2019

Knowledge of abundance, or population size, is fundamental in wildlife conservation and management. Camera-trapping, in combination with capture-recapture methods, has been extensively applied to estimate abundance and density of individually identifiable animals due to the advantages of being non-invasive, effective to survey wide-ranging, elusive, or nocturnal species, operating in inhospitable environment, and taking low labor. We assessed the possibility of using coat patterns from images to identify an individual leopard cat (Prionailurus bengalensis), a Class II endangered species in South Korea. We analyzed leopard cat images taken from Digital Single-Lense Relfex camera (high resolution, 18Mpxl) and camera traps (low resolution, 3.1Mpxl) using HotSpotter, an image matching algorithm. HotSpotter accurately top-ranked an image of the same individual leopard cat with the reference leopard cat image 100% by matching facial and ventral parts. This confirms that facial and ventral fur patterns of the Amur leopard cat are good matching points to be used reliably to identify an individual. We anticipate that the study results will be useful to researchers interested in studying behavior or population parameter estimates of Amur leopard cats based on capture-recapture models.

• Phonetics and Speech Sciences
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• v.12 no.3
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• pp.55-63
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• 2020

Voice conversion can be applied to various voice processing applications. It can also play an important role in data augmentation for speech recognition. The conventional method uses the architecture of voice conversion with speech synthesis, with Mel filter bank as the main parameter. Mel filter bank is well-suited for quick computation of neural networks but cannot be converted into a high-quality waveform without the aid of a vocoder. Further, it is not effective in terms of obtaining data for speech recognition. In this paper, we focus on performing voice-to-voice conversion using only the raw spectrum. We propose a deep learning model based on the transformer network, which quickly learns the voice conversion properties using an attention mechanism between source and target spectral components. The experiments were performed on TIDIGITS data, a series of numbers spoken by an English speaker. The conversion voices were evaluated for naturalness and similarity using mean opinion score (MOS) obtained from 30 participants. Our final results yielded 3.52±0.22 for naturalness and 3.89±0.19 for similarity.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.787-795
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• 2009

This paper presents a histogram equalization based on the logistic function for enhancing the quality of images. The histogram equalization is a simple and effective spatial processing method that it enhances the quality by adjusting the brightness of image. The logistic function that is a nonlinear transformation function is applied to adaptively enhance the brightness of the image according to its intensity level frequency. We propose a flexible and asymmetrical logistic function by only using the intensity level with maximum frequency and the maximum intensity level in an histogram, and the total number of pixels. The proposed function excludes both the computation load of an exponential function and the heuristic setting of an optimal parameter values in the traditional logistic function. The proposed method has been applied for equalizing many images with a different resolution and histogram distribution. The experimental results show that the proposed method has the superior enhancement performances and the faster equalizing speed compared with the traditional histogram equalization and the adaptively modified histogram equalization, respectively. And the proposed histogram equalization can be used in various multimedia systems in real-time.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1053-1056
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• 2008

Permeability coefficient of concrete is a substantial key parameter for understanding the durability performance of concrete and its micro-structural densification. Many researches to deal with the issue have been accomplished, however, it is very rare to deal with the theoretical study on permeability coefficient in connection with carbonation of concrete and the effect of volumetric fraction of cement paste or aggregate on the permeability coefficient. The majority of these researches have not dealt with this issue combined with carbonation of concrete, although carbonation can significantly impact on the permeability coefficient of concrete. The purpose of this study is to establish a fundamental approach to compute the permeability coefficient of (non)carbonated concrete. When simulating micro-structural characteristics as a starting point for deriving a model for the permeability coefficient by the numerical simulation program for cementitious materials, HYMOSTRUC, a more realistic formulation can be achieved. For several compositions of cement pastes, the permeability coefficient is calculated with the analytical formulation, followed by a microstructure-based model. Emphasis is on the micro-structural changes and its effective change of the permeability coefficient of carbonated concrete. The results of micro-structural water permeability coefficient model will be compared with results achieved from permeability experiments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.9
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• pp.783-787
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• 2002

In recent year, B $i_{4-}$x L $a_{x}$ $Ti_3$ $O_{12(BLT)}$ is one of promising substitute materials for the ferroelectric random access memory(FRAM) applications. But the systematic composition is still insufficient, so this experiment was carried out in ceramic ambient sintering process which has the very excellent ferroelectric property. Samples were prepared by a bulk and the purpose which was estimated with a suitability of thin films applications. The density of B $i_{3.75}$ L $a_{0.25}$ $Ti_3$ $O_{12}$ was high and the XRD pattern showed that the intensity of main peak (117) was increased at the argon ambient sintering. Controlling the quantity of oxygen, crystallization showed a thin, long plate like type, and we obtained the excellent dielectric and polarization properties at the argon atmosphere sintering. Also this sintering process was effective at the bulk sample. Argon ambient sintered sample produced higher permittivity of 154, the remanent polarization(2Pr) of 6.8 uC/$\textrm{cm}^2$ compared with that sintered in air and oxygen ambient. And this sintering process showed a possibility which could be applied to thin films process..

• Convergence Security Journal
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• v.13 no.1
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• pp.71-78
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• 2013

In this study, software products developed in the course of testing, software managers in the process of testing software test and test tools for effective learning effects perspective has been studied using the NHPP software. The doubly bounded power law distribution model makeup Weibull distribution applied to distribution was based on finite failure NHPP. Software error detection techniques known in advance, but influencing factors for considering the errors found automatically and learning factors, by prior experience, to find precisely the error factor setting up the testing manager are presented comparing the problem. As a result, the learning factor is greater than automatic error that is generally efficient model could be confirmed. This paper, a numerical example of applying using time between failures and parameter estimation using maximum likelihood estimation method, after the efficiency of the data through trend analysis model selection were efficient using the mean square error and $R^2$.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.1
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• pp.105-111
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• 2003

Wheel for passenger car support the car weight with tires, and they transmit rolling and braking power into the ground. Whittling away at wheel weight is more effective to boost fuel economy than lighting vehicle body structure. A shape of hole in disk is optimized for minimizing the weight of steel wheel. Pro/ENGINEER program is used for formulating the design model, and ANSYS package is selected for analyzing the design model. It has difficulties to interface these commercial software directly. For Combining both programs, response surface methodology is applied to construct approximation functions for maximum stresses and maximum displacements are obtained by full factorial design of five levels. This steel wheel is modeled in 14-inch diameter of rim, and wide parameter of hole in disk is only selected as design variable for reducing the weight of steel whee. PLBA(Pshenichny-Lim-Belegundu-Arora) algorithm, which used the second-order information in the direction finding problem and uses the active set strategy, is used for solving optimization problems.