• Journal of the Korean Applied Science and Technology
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• v.25 no.1
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• pp.52-57
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• 2008

In the present study, impedance characteristics for AgO-Zn cell at various State-of-Charge (SoC) has been studied. The impedance measurements of AgO-Zn cell at various SoC were made over the frequency range from 100kHz to 10mHz with an amplitude 5mV. The impedance parameters have been evaluated by the analysis of the data using an equivalent circuit and a Non-linear least squares (NLLS) fitting method. The total resistances reflects the SoC of the cell. This indicates that the total resistance is important parameter for predicting SoC of AgO-Zn cell.

• Journal of the Korean Data and Information Science Society
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• v.21 no.2
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• pp.241-250
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• 2010

Over the past few decades, several studies have been made on the modeling of circular data. But these studies focused mainly on the symmetrical cases including von Mises distribution. Recently, many studies with skew-normal distribution have been conducted in the linear case. In this paper, we dealt the problem of fitting of non-symmetrical circular data with wrapped skew-normal distribution which can be derived by using the principle of wrapping. Wrapped skew-normal distribution is very flexible to asymmetical data as well as to symmetrical data. Multi-modal data are also fitted by using the mixture of wrapped skew-normal distributions. To estimate the parameters of mixture, we suggested the EM algorithm. Finally we verified the accuracy of the suggested algorithm through simulation studies. Application with real data is also considered.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.1
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• pp.1-6
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• 2015

Factors that have influence on solar power generation are specified into three aspects such as meteorological, geographical factors as well as equipment installation. Meteorological factors influence the most among the three. Insolation, sunshine hours, and cloud directly influence on solar power generation, whereas temperature and wind speed have impacts on equipment installation. This paper provides explanation over temperature-wind speed equation by calculating influence of temperature and wind speed on equipment installation. In order to conduct a research, pyranometer, anemometer, air thermometer, module thermometer are installed in 2MWp solar power plant located in South Cholla province, so that real-time meteorological data and generating amount can be analyzed through monitoring system. Besides, if existing and new methods are applied together, accuracy of prediction for generating amount is improved.

• Current Optics and Photonics
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• v.1 no.5
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• pp.505-513
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• 2017

Measuring the thickness of thin films is strongly required in the display industry. In recent years, as the size of a pattern has become smaller, the substrate has become larger. Consequently, measuring the thickness of the thin film over a wide area with low spatial sampling size has become a key technique of manufacturing-yield management. Interferometry is a well-known metrology technique that offers low spatial sampling size and the ability to measure a wide area; however, there are some limitations in measuring the thickness of the thin film. This paper proposes a method to calculate the thickness of the thin film in the following two steps: first, pre-estimation of the thickness with the phase at the peak position of the interferogram at the bottom surface of the thin film, using white-light phase-shift interferometry; second, accurate correction of the measurement by fitting the interferogram with the theoretical pattern through the estimated thickness. Feasibility and accuracy of the method has been verified by comparing measured values of photoresist pattern samples, manufactured with the halftone display process, to those measured by AFM. As a result, an area of $880{\times}640$ pixels could be measured in 3 seconds, with a measurement error of less than 12%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.3
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• pp.239-244
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• 2020

This study examines the feasibility of the image deep learning method using convolution neural networks (CNNs) to maintain a porcelain insulator. Data augmentation is performed to prevent over-fitting, and the classification performance is evaluated by training the age, material, region, and pollution level of the insulator using image data in which the background and labelling are removed. Based on the results, it was difficult to predict the age, but it was possible to classify 76% of the materials, 60% of the pollution level, and more than 90% of the regions. From the results of this study, we identified the potential and limitations of the CNN classification for the four groups currently classified. However, it was possible to detect discoloration of the porcelain insulator resulting from physical, chemical, and climatic factors. Based on this, it will be possible to estimate the corrosion of the cap and discoloration of the porcelain caused by environmental deterioration, abnormal voltage, and lightning.

• Industrial Engineering and Management Systems
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• v.9 no.2
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• pp.131-140
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• 2010

Biclustering is a method of finding meaningful subsets of objects and attributes simultaneously, which may not be detected by traditional clustering methods. It is popularly used for the analysis of microarray data representing the expression levels of genes by conditions. Usually, biclustering algorithms do not consider a sequential relation between attributes. For time series data, however, bicluster solutions should keep the time sequence. This paper proposes a new biclustering algorithm for time series data by modifying the plaid model. The proposed algorithm introduces a parameter controlling an interval between two selected time points. Also, the pruning step preventing an over-fitting problem is modified so as to eliminate only starting or ending points. Results from artificial data sets show that the proposed method is more suitable for the extraction of biclusters from time series data sets. Moreover, by using the proposed method, we find some interesting observations from real-world time-course microarray data sets and apartment price data sets in metropolitan areas.

• Journal of the Korean Society of Safety
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• v.23 no.6
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• pp.51-56
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• 2008

As RFID/USN technology is used in the latest industry trend, the information analysis paradigm shifts to intelligence service environment. The intelligent service includes autonomic operation, which select activity by defining itself to the status of industry facilities. Furthermore, information analysis based on IT used to frequently data mining for detecting the meaning information and deriving new pattern. This paper suggest self-classifying of context-aware by applying data mining in gas facilities for serving the intelligent gas safety management. We modify data algorithm for fitting the domain of gas safety, construct context-aware model by using the proposed algorithm, and demonstrate our method. As the accuracy of our model is improved over 90%, the our approach can apply to intelligent gas safety management based on RFID/USN environments.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.546-547
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• 2012

In the three-phase power system using the three-phase load, when any one-phase is open-phase, the unbalanced current flows and the single-phase power supplied by power supply produces over-current. As a result, the enormous damage and electrical fire can be given to the power system. In order to improve these problems, this paper is proposed a new control circuit topology for open-phase protection using semiconductor devices. Therefore, the proposed open-phase protection device (OPPD) enhances the sensing speed and precision, and has the advantage of simple fitting in the three-phase distribution panel in the field, as it manufactures into small size and light weight. As a result, the proposed OPPD minimizes the electrical fire from open-phase, and contributes for the stable driving of the power system.

• Journal of Veterinary Clinics
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• v.19 no.3
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• pp.290-294
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• 2002

The frequencies of gamma-ray-induced micronuclei (MN) in cytokinesis-blocked (CB) lymphocytes at several doses were measured in three donors of Korean native cattle and Korean native goat. Measurements performed after irradiation showed a dose-related increases in MN frequency in each of the donors studied. When analysed by linear-quadratic model the line of best fit was cattle : y : 0.1016D +$0.0118D^2$+0.0147, goat : y = 0.1353D +$0.0043D^2$+0.0087 (y : number of MN/CB cells and D = irradiation dose in Gy). The relative sensitivity of goat lymphocytes compared with cattle lymphocytes was estimated by best fitting linear-quadratic model based on the radiation-induced MN data over the range from 0 Gy to 4 Gy. In the case of MN frequency with 0.05, 0.1, 0.2, 0.4 and 0.8, the relative sensitivities of goat lymphocytes were 1.106. 1.166. 1.140, 1.069 and 0.976 respectively. Our in vitro radiobiological study confirmed that the cytogenetic response obtained in blood from cattle and goat can be utilized for application in environmental studies.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.54-63
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• 2006

Enhancement methods of sensitivity to in-plane strain measurement by micro-ESPI(Electronic Speckle Pattern Interferometry) technique were proposed using TiN and Au thin films. Micro-tensile strain over the micro-tensile specimens, prepared in micro-scale by those films, was measured by micro-tensile loading system and micro-ESPI system developed in this study. The subsequent measurement of in-plane tensile strain in the micro-sized specimens was introduced using the micro-ESPI technique, and the micro-tensile stress-strain curves for these films were determined. To enhance the sensitivity to measurement of in-plane tensile strain, algorithms of the phase estimation by using curve fitting of inter-fringe and the discrete Fourier Transform with object-induced dynamic phase shifting were developed. Using these two algorithms, the micro-tensile strain-stress curves were generated. It is shown that the algorithms for enhancement of the sensitivity suggested in this study make the sensitivity to measurement of the in-plane tensile strain increase.