• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.2
• /
• pp.162-168
• /
• 2006

Recently, diagnosis techniques have been investigated to detect a Partial Discharge associated with a dielectric material defect in a high voltage electrical apparatus, However, the properties of detection technique of Partial Discharge aren't completely understood because the physical process of Partial Discharge. Therefore, this paper analyzes the process on surface discharge of polymer insulator using wavelet transform. Wavelet transform provides a direct quantitative measure of spectral content in the time~frequency domain. As it is important to develop a non-contact method for detecting the kaolin contamination degree, this research analyzes the electromagnetic waves emitted from Partial Discharge using wavelet transform. This result experimentally shows the process of Partial Discharge as a two-dimensional distribution in the time-frequency domain. Feature extraction parameter namely, maximum and average of wavelet coefficients values, wavelet coefficients value at the point of $95\%$ in a histogram and number of maximum wavelet coefficient have used electromagnetic wave signals as input signals in the preprocessing process of neural networks in order to identify kaolin contamination rates. As result, root sum square error was produced by the test with a learning of neural networks obtained 0.00828.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.47 no.2
• /
• pp.11-20
• /
• 2010

In this paper we propose a face detection system which consists of a method of face candidate extraction using skin color and a method of face verification using the feature of facial structure. Firstly, the proposed extraction method of face candidate uses the image segmentation and merging algorithm in the regions of skin color and the neighboring regions of skin color. These two algorithms make it possible to select the face candidates from the variety of faces in the image with complicated backgrounds. Secondly, by using the partial face classifier, the proposed face validation method verifies the feature of face structure and then classifies face and non-face. This classifier uses face images only in the learning process and does not consider non-face images in order to use less number of training images. In the experimental, the proposed method of face candidate extraction can find more 9.55% faces on average as face candidates than other methods. Also in the experiment of face and non-face classification, the proposed face validation method obtains the face classification rate on the average 4.97% higher than other face/non-face classifiers when the non-face classification rate is about 99%.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
• /
• 2004.03a
• /
• pp.493-498
• /
• 2004

The objective of the present study is to compare various conventional and recently evolved satellite image-processing techniques and to ascertain the best possible technique that can identify and position of aquaculture farms accurately in and around the Younggwang coastal area. Several conventional techniques performed to extract such information fiom the Landsat-TM imagery do not seem to yield better information about the aquaculture farms, and lead to misclassification. The large errors between the actual and extracted aquaculture farm information are due to existence of spectral confusion and inadequate spatial resolution of the sensor. This leads to possible occurrence of mixture pixels or 'mixels' of the source of errors in the classification techniques. Understanding the confusing and mixture pixel problems requires the development of efficient methods that can enable more reliable extraction of aquaculture farm information. Thus, the more recently evolved methods such as the step-by-step partial spectral end-member extraction and linear spectral unmixing methods are introduced. The farmer one assumes that an end-member, which is often referred to as 'spectrally pure signature' of a target feature, does not appear to be a spectrally pure form, but always mix with the other features at certain proportions. The assumption of the linear spectral unmxing is that the measured reflectance of a pixel is the linear sum of the reflectance of the mixture components that make up that pixel. The classification accuracy of the step-by-step partial end-member extraction improved significantly compared to that obtained from the traditional supervised classifiers. However, this method did not distinguish the aquaculture ponds and non-aquaculture ponds within the region of the aquaculture farming areas. In contrast, the linear spectral unmixing model produced a set of fraction images for the aquaculture, water and soil. Of these, the aquaculture fraction yields good estimates about the proportion of the aquaculture farm in each pixel. The acquired proportion was compared with the values of NDVI and both are positively correlated (R$^2$ =0.91), indicating the reliability of the sub-pixel classification.ixel classification.

• The Korean Journal of Food And Nutrition
• /
• v.10 no.4
• /
• pp.503-508
• /
• 1997

The extraction and separation methods of protein-bound polysaccharides from the mycelium and culture broth of L. edodes were investigated. The use 2% solution of surface active agent, Triton X-100 was effective for extraction of the protein-bound polysaccharide from the mycelium. The extraction of the protein-bound polysaccharides from mycelium with hot water was achieved by 4 hours extraction at 10$0^{\circ}C$. For the separation and partial purification of the protein bound polysaccharides the column chromatography using DEAE-Cellulose, DEAE-Sephadex and Sephadex proved to be effective.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.2
• /
• pp.8-17
• /
• 2000

In this work, two approaches were proposed for the recognition of partial discharge patterns. The first approach was neural network with backpropagation algorithm, and the second approach was angle calculation between t재 operator vectors. PD signals were detected using three electrode systems; IEC(b), needle-plane and CIGRE method II electrode system. Both of neural network and angle comparison method showed good recognition performance for the patterns similar to the trained patterns. And the number of operators to be used had a great influence on the recognition performance to the untrained patterns.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.49 no.11
• /
• pp.616-621
• /
• 2000

This paper deals with the multiresolution analysis of wavelet transform for partial discharge(PD). Test arrangement is based on the needle-plane electrode system and applied AC high voltage. The measured PD signal was decomposed into "approximations" and "details". The approximation are the high scale, low-frequency components of the PD signal. The details are the low-scale, high frequency components. The decomposition process are iterated to 3 level, with successive approximation being decomposed in turn, so that PD signal is broken down into many lower-resolution components. Through the procedure of signal wavelet transform, signal noise extraction and signal reconstruction, the signal is analyzed to determine the magnitude of PD.

• Restorative Dentistry and Endodontics
• /
• v.36 no.3
• /
• pp.211-218
• /
• 2011

Purpose: Intentional replantation (IR) is a suitable treatment option when nonsurgical retreatment and periradicular surgery are unfeasible. For successful IR, fracture-free safe extraction is crucial step. Recently, a new extraction method of atraumatic safe extraction (ASE) for IR has been introduced. Patients and Methods: Ninety-six patients with the following conditions who underwent IR at the Department of Conservative Dentistry, Seoul National University Bundang Hospital, in 2010 were enrolled in this study: failed nonsurgical retreatment and periradicular surgery not recommended because of anatomical limitations or when rejected by the patient. Preoperative orthodontic extrusive force was applied for 2-3 weeks to increase mobility and periodontal ligament volume. A Physics Forceps was used for extraction and the success rate of ASE was assessed. Results: Ninety-six premolars and molars were treated by IR. The complete success rate (no crown and root fracture) was 93% (n = 89); the limited success rates because of partial root tip fracture and partial osteotomy were 2% (n = 2) and 5% (n = 5), respectively. The clinical and overall success rates of ASE were 95% and 100%, respectively; no failure was observed. Conclusions: ASE can be regarded as a reproducible, predictable method of extraction for IR.

• Proceedings of the IEEK Conference
• /
• 2001.09a
• /
• pp.179-182
• /
• 2001

In this paper. a key frame extraction algorithm for browsing and searching the summary of a video is proposed. Toward this end, important frames representing a shot are selected according to the correlations among frames. by using the Fourier descriptor which is useful for the shot boundary detection. To quantitatively evaluate the importance of selected frames. a new measure based on correlation coefficients of frames is proposed. If there are several frames with a same importance. another criteria is introduced to break the tie. by computing the partial moment of subframes including each candidate key frame so that the distortion rate is minimized Since a key frame extraction algorithm can be evaluated subjectively. the performance of the proposed algorithm has been verified by a statistical test. Experiments show that more than 20% improvement has been obtained by the proposed algorithm compared to existing methods.

• The Korean Journal of Food And Nutrition
• /
• v.21 no.2
• /
• pp.143-147
• /
• 2008

To develop a new anti-wrinkle agent from medicinal plants, this study investigated the optimal conditions for extracting elastase inhibitor from Rheum undulatum L. Maximal extraction occurred by using 70% methanol at $50^{\circ}C$ for 24 hr; the elastase inhibitory activity was 60.4%($IC_{50}:6.7{\times}10^3{\mu}g/m{\ell}$). Systematic solvent extraction, thin layer chromatography, silica gel column chromatography, Sephadex LH-20 column chromatography, and reverse-phase high performance liquid chromatography were used in the partial purification of the elastase inhibitor. The compound was soluble in dimethylsulfoxide, methanol, and ethanol, and had maximum absorption spectra at 231.5 nm and 275.5 nm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.225-226
• /
• 2005

In this Study, we have acquired 5-simulation Fault types Signals of high voltage Motor stator winding using epoxy/mica coupler. In order to know stator winding fault type using fault signals, we have performed feature extraction to apply wavelet transform technique. we have obtained skewness and kurtosis as statistical parameters of fault signal pattern from non deterioration state winding. We have know that 5 fault signals types have done an exponential function pattern shape but individually fault a class widely was different each other a signal waveform of pattern.