• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.106-112
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• 2012

Real-life time series characteristic data has significant amount of non-stationary components, especially periodic components in nature. Extracting such components has required many ad-hoc techniques with external parameters set by users in case-by-case manner. In our study, we evaluate whether Hilbert-Huang Transform, a new tool of time-series analysis can be used for effective analysis of such data. It is divided into two points : 1) how effective it is in finding periodic components, 2) whether we can use its results directly in detecting values outside control limits, for which a traditional method such as ARIMA had been used. We use glass furnace temperature data to illustrate the method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.35-41
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• 2014

Real-life time series characteristic data has significant amount of non-stationary components, especially periodic components in nature. Extracting such components has required many ad-hoc techniques with external parameters set by users in a case-by-case manner. In this study, we used Empirical Mode Decomposition Method from Hilbert-Huang Transform to extract them in a systematic manner with least number of ad-hoc parameters set by users. After the periodic components are removed, the remaining time-series data can be analyzed with traditional methods such as ARIMA model. Then we suggest a different way of setting control chart limits for characteristic data with periodic components in addition to ARIMA components.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.494-500
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• 2008

This paper presents the analyzed result of the series arc fault current by using the discrete wavelet transform. The series arcing is caused by a loose connection in series with the load circuit. The series arc current is limited to a moderate value by the resistance of the device connected to the circuit, such as an appliance or a lighting system. The amount of energy in the sparks from the series arcing is less than in the case of parallel arcing but only a few amps are enough to be a fire hazard. Therefore, it is hard to detect the distinctive difference between a normal current and a intermittent arc current. This paper, presents the variation of the ratio of peak values and RMS values of the series arc fault current, and proposes the novel series arc fault detecting method by using the discrete wavelet transform. Loads such as a CFL lamp, a vacuum cleaner, a personal computer, and a television, which has the very similar normal current with the arc current, were selected to confirm the novel method.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.3
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• pp.146-152
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• 2006

In order to analyze the characteristics of series arcs that could happen in poor connections of electrical facilities, we made an apparatus which is similar to actual situation. series arcs are generated between copper and copper, copper and bronze, copper and brass, bronze and bronze, and then oxidation growth and voltage waveform were measured. A very small vibration with constant movement is needed to grow oxidation initially, whereas oxidation growth proceeded without a vibration after a certain amount of time. At first, blue white flame was generated initially between copper and copper, and then yellow flame was generated. In case of contact between copper and copper, the length of oxidation growth was about 7.1[mm] in 90[min]. In case of contact between copper and brass, the length of oxidation growth was about 4.3[mm] in 90[min], When bronze is contacted with copper, the lengths of oxidation growth were about 1.4[mm] in 20[min] and 2.7[mm] in 40[min] respectively, and no more oxidation growth was shown after that. In case of contact between brass and brass, the length of oxidation growth was about 1.2[mm] in 90[min], so it was the smallest compared to other cases. When copper is contacted with copper, the current through the load was about 1.6[A] and the power dissipation increased from 19[W] to 31[W]. In case of oxidation growth between copper and brass, the voltage changed from 8.4[V] to 11[V]. However, the voltage drop and the power dissipation between copper and brass were small compared to oxidation growth between copper and copper. When series arcs were generated between bronze and copper, a peak was shown at the beginning of voltage increase, and 40[min] later, oxidation material was not grown any longer. When oxidation growth occurred, voltage waveform showed irregular waveforms with tiny ripples.

• Membrane Journal
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• v.25 no.3
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• pp.239-247
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• 2015

The new types of phosphazene diagnostic membranes have been prepared for blood glucose measurements. The possible interferents in human blood were sorted into 4 different series and their effects on the glucose measurements were examined. In case of series I which indicates the lowest concentration, most of them did not show any serious effects on the blood glucose measurements, but only ascorbic acid (AA) showed 5~8% higher values compared to K/S values of the standard solution. In case of series II, all of four interferents showed 3~4% lower K/S values than those of plasma, but they showed consistent values by concentration variation. In case of series III, all of three interferents did not show any big differences compared to the standard solution. In case of series IV which indicates the highest concentration, two interferents showed 11~15% lower K/S values than the standard values, however they did not any serious effect on the blood glucose measurements.

• Imaging Science in Dentistry
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• v.43 no.4
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• pp.283-287
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• 2013

Purpose: This study was performed to determine the prevalence and characteristics of pneumatized articular tubercle or eminence among a defined group of Iranian people. Materials and Methods: Digital panoramic radiographs of 1694 patients in the Department of Oral and Maxillofacial Radiology, Hamadan Dental School, Iran were evaluated retrospectively to detect the above lesion. Finally, 1563 radiographs were selected according to inclusion criteria. Then, a review was done of 10 large case series found using a MEDLINE search of the literature. Chi-squared test was used to analyze the differences in variables such as age, gender, laterality, and locularity in our case series. Results: The average age of our samples was $32.6{\pm}7.63$ years. Pneumatized articular tubercle was found in 98 cases, representing a prevalence of 6.2% with a mean age of $22.8{\pm}7.9$ and a range of 8 to 60 years. Sixty-four (65.3%) pneumatized articular tubercles were unilateral, with 30 lesions on the right and 34 on the left side. Bilateral lesions were found in 34 (34.7%) patients. 52 (53.06%) of the pneumatized articular tubercles were of the unilocular type and 46 (46.94%) were multilocular. The results showed no statistically significant differences regarding age (p=0.454), gender (p=0.634), laterality (p=0.252), or locularity (p=0.807) among the samples. Conclusion: Among ten large case series from other countries, the prevalence of pneumatized articular tubercle (6.2%) in Iranian patients was higher than that of all eight of the case series that used the same detection method as the present study of panoramic radiography.

• Journal of the Korean Data and Information Science Society
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• v.14 no.2
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• pp.265-274
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• 2003

Time series data are influenced by the external events such as holiday, strike, oil shock, and political change, so the external events cause a sudden change to the time series data. We regard the observation as outlier that occurred as a result of external events. In general, it is called intervention if we know the period and the reason of external events, and it makes an analyst difficult to establish a time series model. Therefore, it is important that we analyze the styles and effects of intervention. In this paper, we considered the linear time series model with invention and compared with nonlinear time series models such as ARCH, GARCH model and also we compared with the combination prediction method that Tong(1990) introduced. In the practical case study, we compared prediction power with RMSE among linear, nonlinear time series model with intervention and combination prediction method.

• Communications for Statistical Applications and Methods
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• v.17 no.3
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• pp.377-390
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• 2010

In the case of time-series analysis, it is often more convenient to rely on the frequency domain than the time domain. Spectral density is the core of the frequency-domain analysis that describes autocorrelation structures in a time-series process. Possible ways to estimate spectral density are to compute a periodogram or to average the periodogram over some frequencies with (un)equal weights. This can be an attractive tool to measure the similarity between time-series processes. We employ the metrics based on a smoothed periodogram proposed by Park and Kim (2008) for the classification of different classes of time-series processes. We consider several lag windows with unequal weights instead of a modified Daniel's window used in Park and Kim (2008). We evaluate the performance under various simulation scenarios. Simulation results reveal that the metrics used in this study split the time series into the preassigned clusters better than do the raw-periodogram based ones proposed by Caiado et al. 2006. Our metrics are applied to an economic time-series dataset.

• Herbal Formula Science
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• v.26 no.4
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• pp.363-380
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• 2018

Objectives : We analyzed the principle of compatibility of socheongnyong-tang and expanded the range of application in clinical practice. Methods : Socheongnyong-tang was analyzed by the compatibility principle through the system of chief, deputy, assistant, and envoy, but the basic formulas of "Discussion of Cold Damage" and "Synopsis of the Golden Chamber" was used. Results : Socheongnyong-tang treats exterior wind-cold and interior water accumulation. Exterior wind-cold is treated mainly by exterior-releasing herbs constituting mahwang-tang and gyeji-tang in "Discussion of Cold Damage", and interior water accumulation is treated mainly by retained fluid-resolving herbs constituting yeonggamomigangsinha-tang, yeonggamomigagangsinbanhahaengin-tang and yeonggamomigagangsinbanhaengdaehwang-tang in "Synopsis of the Golden Chamber". Depending on the weight of exterior wind-cold and interior water accumulation, the disease condition is classified as a case where exterior wind-cold is heavier than interior water accumulation, a case where exterior wind-cold is lighter than interior water accumulation, and a case where it is equivalent. When exterior wind-cold is heavier than interior water accumulation, chief herbs are Ephedrae Herba and Cinnamomi Ramulus of exterior-releasing herbs series and deputy herbs are Zingiberis Rhizoma and Asari Radix et Rhizoma of retained fluid-resolving herbs series. When exterior wind-cold is equal to the disease condition of interior water accumulation, chief herbs are Ephedrae Herba of exterior-releasing herbs series and Zingiberis Rhizoma of retained fluid-resolving herbs series, and deputy herbs are Cinnamomi Ramulus of the exterior-releasing herbs series and Asari Radix et Rhizoma of retained fluid-resolving herbs series. When exterior wind-cold is lighter than interior water accumulation, chief herbs are Zingiberis Rhizoma and Asari Radix et Rhizoma of retained fluid-resolving herbs series and deputy herbs are Ephedrae Herba and Cinnamomi Ramulus of exterior-releasing herbs series. In any case, assistant herbs are Pinelliae Rhizoma, Paeoniae Radix alba, and Schisandrae Fructus, and envoy herb is Glycyrrhizae Radix preparata. Conclusions : In conclusion, socheongnyong-tang must differently formulate the system of chief, deputy, assistant, and envoy according to the grade of exterior wind-cold and interior water accumulation. These results suggest that socheongnyong-tang can be applied flexibly when applied in clinical practice to enhance the therapeutic effect.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.609-615
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• 2001

This study proposes analysis and evaluation method of time series ultrasonic signal using attractor analysis for fusion joint part of polyethylene piping. Quantitatively characteristics of fusion joint part is analysed features extracted from time series. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics. These differences in characteristics of fusion joint part enables the evaluation of unique characteristics of fusion joint part. In quantitative fractal feature extraction, feature values of 4.291 in the case of debonding and 3.694 in the case of bonding were proposed on the basis of fractal dimensions. In quantitative quadrant feature extraction, 1,306 point in the case of bonding(one quadrant) and 1,209 point(one quadrant) in the case of debonding were proposed on the basis of fractal dimensions. Proposed attractor feature extraction can be used for integrity evaluation of polyethylene piping material which is in case of bonding or debonding.