• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.193-203
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• 2016

This paper forecasts electricity demand as a critical element of a demand management system in Smart Grid environment. We present a prediction method of using a combination of predictive values by time series clustering. Periodogram-based normalized clustering, predictive analysis clustering and dynamic time warping (DTW) clustering are proposed for time series clustering methods. Double Seasonal Holt-Winters (DSHW), Trigonometric, Box-Cox transform, ARMA errors, Trend and Seasonal components (TBATS), Fractional ARIMA (FARIMA) are used for demand forecasting based on clustering. Results show that the time series clustering method provides a better performances than the method using total amount of electricity demand in terms of the Mean Absolute Percentage Error (MAPE).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.4
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• pp.41-49
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• 2012

The objective of this study is to investigate the characteristics of the location and prospects of the bear shelves built by Asiatic black bears in the Jirisan National Park. Previous researchers have been analyzed bear shelves in terms of places for resting and eating, but we are going to analyze based on the prospect-and-refuge theory. Characteristics of the sites of bear shelves are measured through field survey and topographic analysis by using digital elevation model (DEM). The normalized difference vegetation index (NDVI) is used to evaluate the optimum location of bear shelves in terms of crown density. Man-made objects are identified by viewshed analysis based on geographical information system (GIS). Findings of this paper can be summarized as follows. First, most bear trees are located deep inside of the mountainous national park, slopes of 30~40 degrees, altitude of 400~1,200m, and relatively low vegetation density with NDVI value of 0.4~0.6 compared to the average NDVI of the park. Second, the average height of bear shelves is 12.44m, or 74% of the average height of bear trees. They are located at suitable places to observe nearby trails and other park facilities. Third, man-made objects within the 100m radius of bear trees include lodge, bear training center, beekeeping camp, and hiking trails. Thus we may temporarily conclude that one of the main criteria of the bear tree selection in the park has been to identify optimum places for the monitoring of human activities in their habitat.

• Journal of Broadcast Engineering
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• v.15 no.2
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• pp.182-191
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• 2010

In this paper, a simple Carrier Frequency Recovery(CFR) scheme is introduced. In relating the use of consumer-grade equipment and satellite transmission environments, carrier frequency recovery have to recovery a large initial Carrier Frequency Offset(CFO), which is 20% normalized CFO, for DVB-S2 receivers. For these reasons, conventional CFR schemes for DVB-S2 systems need significant hardware complexity. Introduced CFR scheme employs Fitz algorithm for coarse CFR and recovers a coarse CFO accurately, and a simple pilot block correlation algorithm is employed for fine CFR. Introduced scheme reduce the number of multiplication operations by 80% and does not need any additional memory without degrading the achievable performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1904-1926
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• 2016

Iris recognition for biometric personnel identification has gained much interest owing to the increasing concern with security today. The image quality plays a major role in the performance of iris recognition systems. When capturing an iris image under uncontrolled conditions and dealing with non-cooperative people, the chance of getting non-ideal images is very high owing to poor focus, off-angle, noise, motion blur, occlusion of eyelashes and eyelids, and wearing glasses. In order to improve the accuracy of iris recognition while dealing with non-ideal iris images, we propose a novel algorithm that improves the quality of degraded iris images. First, the iris image is localized properly to obtain accurate iris boundary detection, and then the iris image is normalized to obtain a fixed size. Second, the valid region (iris region) is extracted from the segmented iris image to obtain only the iris region. Third, to get a well-distributed texture image, bilinear interpolation is used on the segmented valid iris gray image. Using contrast-limited adaptive histogram equalization (CLAHE) enhances the low contrast of the resulting interpolated image. The results of CLAHE are further improved by stretching the maximum and minimum values to 0-255 by using histogram-stretching technique. The gray texture information is extracted by 1D Gabor filters while the Hamming distance technique is chosen as a metric for recognition. The NICE-II training dataset taken from UBRIS.v2 was used for the experiment. Results of the proposed method outperformed other methods in terms of equal error rate (EER).

• Journal of Pharmacopuncture
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• v.20 no.1
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• pp.45-51
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• 2017

Objectives: This study aimed to evaluate the hypoglycemic effects of an ethanol extract of Cassia abbreviata (ECA) bark and the possible mechanisms of its action in diabetic albino rats. Methods: ECA was prepared by soaking the powdered plant material in 70% ethanol. It was filtered and made solvent-free by evaporation on a rotary evaporator. Type 2 diabetes was induced in albino rats by injecting 35 mg/kg body weight (bw) of streptozotocin after having fed the rats a high-fat diet for 2 weeks. Diabetic rats were divided into ECA-150, ECA-300 and Metformin (MET)-180 groups, where the numbers are the doses in mg.kg.bw administered to the groups. Normal (NC) and diabetic (DC) controls were given distilled water. The animals had their fasting blood glucose levels and body weights determined every 7 days for 21 days. Oral glucose tolerance tests (OGTTs) were carried out in all animals at the beginning and the end of the experiment. Liver and kidney samples were harvested for glucose 6 phosphatase (G6Pase) and hexokinase activity analyses. Small intestines and diaphragms from normal rats were used for ${\alpha}-glucosidase$ and glucose uptake studies against the extract. Results: Two doses, 150 and 300 mg/kg bw, significantly reduced the fasting blood glucose levels in diabetic rats and helped them maintain normal body weights. The glucose level in DC rats significantly increased while their body weights decreased. The 150 mg/kg bw dose significantly increased hexokinase and decreased G6Pase activities in the liver and the kidneys. ECA inhibited ${\alpha}-glucosidase$ activity and promoted glucose uptake in the rats' hemi-diaphragms. Conclusion: This study revealed that ECA normalized blood glucose levels and body weights in type 2 diabetic rats. The normalization of the glucose levels may possibly be due to inhibition of ${\alpha}-glucosidase$, decreased G6Pase activity, increased hexokinase activity and improved glucose uptake by muscle tissues.

• Structural Engineering and Mechanics
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• v.59 no.3
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• pp.455-473
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• 2016

Methods for the seismic demands evaluation of structures require iterative procedures. Many studies dealt with the development of different inelastic spectra with the aim to simplify the evaluation of inelastic deformations and performance of structures. Recently, the concept of inelastic spectra has been adopted in the global scheme of the Performance-Based Seismic Design (PBSD) through Capacity-Spectrum Method (CSM). For instance, the Modal Pushover Analysis (MPA) has been proved to provide accurate results for inelastic buildings to a similar degree of accuracy than the Response Spectrum Analysis (RSA) in estimating peak response for elastic buildings. In this paper, a simplified nonlinear procedure for evaluation of the seismic demand of structures is proposed with its applicability to multi-degree-of-freedom (MDOF) systems. The basic concept is to write the equation of motion of (MDOF) system into series of normal modes based on an inelastic modal decomposition in terms of ductility factor. The accuracy of the proposed procedure is verified against the Nonlinear Time History Analysis (NL-THA) results and Uncoupled Modal Response History Analysis (UMRHA) of a 9-story steel building subjected to El-Centro 1940 (N/S) as a first application. The comparison shows that the new theoretical approach is capable to provide accurate peak response with those obtained when using the NL-THA analysis. After that, a simplified nonlinear spectral analysis is proposed and illustrated by examples in order to describe inelastic response spectra and to relate it to the capacity curve (Pushover curve) by a new parameter of control, called normalized yield strength coefficient (${\eta}$). In the second application, the proposed procedure is verified against the NL-THA analysis results of two buildings for 80 selected real ground motions.

• Structural Engineering and Mechanics
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• v.43 no.5
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• pp.691-709
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• 2012

This paper provides a variety of viewpoints to illustrate the mechanism of the deck-stay interaction with the appropriate initial shapes of cable-stayed bridges. Based on the smooth and convergent bridge shapes obtained by the initial shape analysis, the one-element cable system (OECS) and multi-element cable system (MECS) models of the Kao Ping Hsi Bridge in Taiwan are developed to verify the applicability of the analytical model and numerical formulation from the field observations in the authors' previous work. For this purpose, the modal analysis of the two finite element models are conducted to calculate the natural frequency and normalized mode shape of the individual modes of the bridge. The modal coupling assessment is also performed to obtain the generalized mass ratios among the structural components for each mode of the bridge. The findings indicate that the coupled modes are attributed to the frequency loci veering and mode localization when the "pure" deck-tower frequency and the "pure" stay cable frequency approach one another, implying that the mode shapes of such coupled modes are simply different from those of the deck-tower system or stay cables alone. The distribution of the generalized mass ratios between the deck-tower system and stay cables are useful indices for quantitatively assessing the degree of coupling for each mode. These results are demonstrated to fully understand the mechanism of the deck-stay interaction with the appropriate initial shapes of cable-stayed bridges.

• The Journal of Korean Obstetrics and Gynecology
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• v.28 no.4
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• pp.46-56
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• 2015

Objectives : Cold hypersensitivity has been regarded to be associated with Autonomic Nervous System (ANS). This study aims to investigate the indicator of cold hypersensitivity of hands and evaluate the correlation between indicator of coldness of hands and Heart Rate Variability (HRV). Methods : We studied 55 patients with cold hypersensitivity of hands who visited in SeMyung University Hospital from 17 August 2015 to 21 August 2015. Thermometer and VAS scale were used for the diagnosis of cold hypersensitivity. After careful examination to rule out other disease which may affect thermometer and HRV data, patients were taken thermometer, those with thermal difference between upper arm (L4) and palm(P8), also asked to answer a VAS scale of cold hypersensitivity of hands, VAS more than 4 were enrolled for evaluation. Results : There was significant correlation between L4-P8 temperature difference and VAS score of cold hypersensitivity. In HRV data, normalized high frequency (HF normal) was significantly correlated with L4-P8 temperature difference, which was objective indicator of cold hypersensitivity of hands. Conclusions : L4-P8 temperature difference using thermometer is objective indicator of cold hypersensitivity, based on VAS scale. Cold hypersensitivity is highly related with ANS, regulating body heat and temperature. HRV is considered to be widely used in cold hypersensitivity in hands for evaluation of ANS.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.2
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• pp.122-129
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• 2014

Identification of the whipping response out of the combined wave-vibration response of a flexible sea going vessel is one of the most interesting research topic from ship designer's point of view. In order to achieve this goal, a novel methodology based on the wavelet cross-correlation technique was proposed in this paper. The cross-correlation of the wavelet power spectrum averaged across the frequency axis was introduced to check the similarity between the combined wave-vibration response and impulse response. The calculated cross-correlation of the wavelet power spectrum was normalized by the auto-correlation of the each spectrum with zero time lag, eventually providing the cross-correlation coefficient that stays between 0 and 1, precisely indicating the existence of the impulse response buried in the combined wave-vibration response. Additionally, the weight function was introduced while calculating the cross-correlation of the two spectrums in order to filter out the signal of lower frequency so that the accuracy of the similarity check becomes as high as possible. The validity of the proposed methodology was checked through the application to the artificially generated ideal combined wave-vibration signal, together with the more realistic signal obtained by running 3D hydroelasticity program WISH-Flex. The correspondence of the identified whipping instances between the results, one from the proposed method and the other from the calculated slamming modal force, was excellent.

• The Journal of the Petrological Society of Korea
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• v.17 no.3
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• pp.133-143
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• 2008

On the basis of chemical composition of granite, gneiss and their weathering products, in this paper, rare earth elements (REEs) was estimated as tracer for clarifying a geochemical variance of earth surface material during weathering process. The chemical composition of clay, clay ware and pottery also were measured for testifying usefulness of REE geochemistry in clarifying the source material of pottery. It was observed that there was no systematic variation of chemical composition among source rock, weathered rock and soil during weathering process. The chemical composition of clay, clay ware and pottery also did not show systematic variation by baking pottery. However, PAAS (Post Archean Australian Shale)-normalized REE patterns of rock-weathered rock-soil and clay-clay ware-pottery are similar regardless of weathering process or ceramic art. Our results confirm that REE geochemistry is powerful tool for clarifying the source materials of surface sediment or archaeological ceramic products.