• Korean Journal of Remote Sensing
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• v.28 no.6
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• pp.635-651
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• 2012

To produce a level-3 monthly composite image from daily level-2 Sea-viewing Wide Field-of-view Sensor (SeaWiFS) chlorophyll-a concentration data set in the East Sea, we applied four average methods such as the simple average method, the geometric mean method, the maximum likelihood average method, and the weighted averaging method. Prior to performing each averaging method, we classified all pixels into normal pixels and abnormal speckles with anomalously high chlorophyll-a concentrations to eliminate speckles from the following procedure for composite methods. As a result, all composite maps did not contain the erratic effect of speckles. The geometric mean method tended to underestimate chlorophyll-a concentration values all the time as compared with other methods. The weighted averaging method was quite similar to the simple average method, however, it had a tendency to be overestimated at high-value range of chlorophyll-a concentration. Maximum likelihood method was almost similar to the simple average method by demonstrating small variance and high correlation (r=0.9962) of the differences between the two. However, it still had the disadvantage that it was very sensitive in the presence of speckles within a bin. The geometric mean was most significantly deviated from the remaining methods regardless of the magnitude of chlorophyll-a concentration values. Its bias error tended to be large when the standard deviation within a bin increased with less uniformity. It was more biased when data uniformity became small. All the methods exhibited large errors as chlorophyll-a concentration values dominantly scatter in terms of time and space. This study emphasizes the importance of the speckle removal process and proper selection of average methods to reduce composite errors for diverse scientific applications of satellite-derived chlorophyll-a concentration data.

• Journal of Environmental Science International
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• v.33 no.2
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• pp.179-185
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• 2024

This study aimed to evaluate the differences in canine preferences for pet food terrine according to the processing method. As companion dogs, three male Spitz canines (average age 12 years, average weight 7 kg) and three male Spitz mix canines (average age 12 years, average weight 5 kg) were used in Experiment 1, whereas five male (average age 10 years, average weight 9 kg) and five female Shetland Sheepdogs (Sheltie, average age 10 years, average weight 8 kg) were used in Experiment 2, to evaluate their preferences and intake types. In both experiments, all dog categories mostly preferred 'meat' when it came to their first choice of food consumed, followed by 'vegetables', 'mixed eating', and 'vegetable leftover' last. This confirms means that canines are carnivores, and over time, choosing 'vegetables' or 'vegetable leftovers' as a secondary or alternate food source can be considered a natural process. When provided various terrines, canines in both experiments first ingested 'cooked' rather than 'freeze-dried' duck, chicken, beef, and pork terrines when selecting food at the start of feeding. For both experiments, most of the intake types using duck, chicken, beef, and pork terrine showed a preference for 'after consuming cooked terrine first and then intake freeze-dried' item. In conclusion, the reason for preferring cooked terrine can be attributed to the difference in the preparation cooking method of freeze-dried cooked terrine.

• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.813-822
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• 2001

In this paper we proposed four data migration methods based on time segmented storage structure including past segment, current segment, and future segment. The migration methods proposed in this paper are the Time Granularity migration method, the LST-GET (Least valid Start Time-Greatest valid End Time) migration method, the AST-AET (Average valid Start Time-Average valid End Time) migration method, and the Min-Overlap migration method. In the each data migration method we define the dividing criterion among segments and entity versions to store on each segment. We measured the response time of queries for the proposed migration methods. When there are no LLTs (Long Lived Tuples), the average response time of AST-AET migration method and LST-GET migration method are smaller than that of Time Granularity migration method. In case of existing LLT, the performance of the LST-GET migration method decreased. The AST-AET migration method resulted in better performance for queries than the Time Granularity migration method and the LST-GET migration method. The Min-Overlap migration method resulted in the almost equal performance for queries compared with the AST-AET migration method, in case of storage utilization more efficient than the AST-AET.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.4
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• pp.16-22
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• 2013

This paper presents a method to analyze the voltage sag data obtained from monitoring systems. In order to establish effective countermeasures against voltage sag problems, an assessment of the system performance with respect to voltage sags is needed. Generally, the average annual sag frequency can be estimated by using the recorded voltage sag events for several years. However, the simple average value can not give the information about the errors of estimation. Such an average estimation is not useful for establishing effective solutions for voltage sag problems. Therefore, this paper proposes an effective method based on the Interval Estimation method. The estimation of voltage sag frequency is performed by using the average frequency and Poisson probability model. The proposed method can give the expected annual sag frequency and upper one-sided bound frequency.

• Journal of Biomedical Engineering Research
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• v.38 no.5
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• pp.232-236
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• 2017

In this study, We investigated the effect of foot cooling on the reduction of body temperature after hard exercise at the high temperature of $40^{\circ}C$. We performed a total of 30 subjects, and the subjects performed treadmill exercise for 30 minutes. We produced the cooling device to cool the foot using Peltier module. After the end of the exercise, We performed normal recovery method and cooling recovery method(one foot, both feet) for 1 hour on the same indoor environmental conditions and confirmed the change of body temperature of subjects. The results of deep body temperature measurement showed average $38.78{\pm}0.22^{\circ}C$ to $38.54{\pm}0.15^{\circ}C$ when the normal recovery method was performed. Cooling recovery method on one foot showed average $38.69{\pm}0.14^{\circ}C$ to average $38.06{\pm}0.17^{\circ}C$ and Cooling recovery method on both feet showed average $38.69{\pm}0.15^{\circ}C$ to average $37.84{\pm}0.21^{\circ}C$. There was a significant difference between the normal recovery method and the one foot cooling recovery method(p < .05), there was a significant difference between the normal recovery method and the both feet cooling recovery method(p < .05) and there was a significant difference between the one foot cooling recovery method and the both feet cooling recovery method(p < .05). Body temperature showed the lowest decrease rate when the normal recovery method was performed, and body temperature showed the highest decrease rate when the both feet cooling recovery method was performed. Therefore, recovery of cooling on the foot after hard exercise have decreased body temperature, delay fatigue in the body, and will be contributed to improvement of athlete performance.

• Journal of the Korean Society for Heat Treatment
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• v.12 no.2
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• pp.157-165
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• 1999

Grain size of steels is one of the most important parameters which influence yield strength and fracture toughness. Ultrasonic wave propagating in polycrystalline materials is mostly attenuated by scattering at grain boundary. Effect of ultrasonic attenuation on average ferrite grain size of carbon steels with tensile strength $40{\sim}60kgf/mm^2$ consisting of multi phases such as ferrite + pearlite and ferrite + pearlite + bainite was evaluated. The attenuation of these steels rapidly increased with average ferrite grain diameter. Average ferrite grain diameter ($D_{av}$, ${\mu}m$) could be expressed as $1.79+22.97*a^{1/2.03}$, where a is attenuation with unit of nepers/cm. From this study, it was confirmed that nondestructive ultrasonic method could be used in measuring average ferrite grain size indirectly.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.9-21
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• 2020

The aim of this paper is to predict the Borsa Istanbul (BIST) 30 index movements to determine the most accurate buy and sell decisions using the methods of Artificial Neural Networks (ANN) and Genetic Algorithm (GA). We combined these two methods to obtain a hybrid intelligence method, which we apply. In the financial markets, over 100 technical indicators can be used. However, several of them are preferred by analysts. In this study, we employed nine of these technical indicators. They are moving average convergence divergence (MACD), relative strength index (RSI), commodity channel index (CCI), momentum, directional movement index (DMI), stochastic oscillator, on-balance volume (OBV), average directional movement index (ADX), and simple moving averages (3-day moving average, 5-day moving average, 10-day moving average, 14-day moving average, 20-day moving average, 22-day moving average, 50-day moving average, 100-day moving average, 200-day moving average). In this regard, we combined these two techniques and obtained a hybrid intelligence method. By applying this hybrid model to each of these indicators, we forecast the movements of the Borsa Istanbul (BIST) 30 index. The experimental result indicates that our best proposed hybrid model has a successful forecast rate of 75%, which is higher than the single ANN or GA forecasting models.

• Journal of Power Electronics
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• v.12 no.3
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• pp.410-417
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• 2012

In this paper, a direct current control method based on a one-cycle controller (DCOCC) for double frequency buck converters (DF buck) is proposed. This control method can make the average current through the high frequency and low frequency inductors of a DF buck converter equal. This is similar to the average current control method. However, the design of the loop compensator is much easier when compared with the average current control. Since the average current though the high frequency and low frequency inductors is equivalent, the current stress of the high frequency switches and the switch losses are minimized. Therefore, the efficiency of the DF buck converter is improved. Firstly, the operation principle of DCOCC is described, then the small signal models of a one cycle controller and a DF buck converter are presented based on the state space average method. Eventually, a system block diagram of the DCOCC controlled DF buck is established and the compensator is designed. Finally, simulation and experiment results are given to verify the correction of the theory analysis.

• Journal of the Korean Statistical Society
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• v.23 no.1
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• pp.89-102
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• 1994

A new method for approximating the average run length (ARL) of cumulative sum (CUSUM) chart is proposed. This method uses the conditional expectation for the test statistic before the stopping time and its asymptotic conditional density function. The values obtained by this method are compared with some other methods in normal and exponential case.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.466-467
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• 2010

Researches about DSTATCOM are mainly divided two parts, one is the calculation of the load-side average active power and dc-link capacitor average voltage, the other part is the current control. This paper proposes a calculation of dc-link capacitor average voltage using improved method instead of conventional method using LPF (low pass filter). Through the theoretical analysis and simulation under unbalance loads and non-linear load, the proposed method is verified.