• Journal of Environmental Science International
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• v.19 no.7
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• pp.819-827
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• 2010

This study was conducted to investigate runoff characteristics of non-point pollutants source at the urban area in boeun area, Chungbuk Province. The monitoring site covering the watershed of $2.11\;km^2$ contains about 40.3 % of total watershed with the urban area. The monitoring was conducted with six events for five months and Event Mean Concentration(EMC) and Site Mean Concentration(SMC) of SS, BOD, CODMn, T-N, T-P were calculated on the result of the water quality parameters. As a result of the comparion between Arithmetic Mean Concentration and Event Mean Concentration, it showed that over all Event Mean Concentration was higher than Arithmetic Mean Concentration. And it showed that SS, BOD, T-P featured the first-flushing effect, showing relatively high concentration in early-stage storm event.

• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.85-96
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• 1994

In this study, 24 curved resin blocks were prepared by one of the following four methods: 1) Conventional technique using K-flexo files 2) Step-back technique using K-flexo files 3) Crown-down technique using K-flexo files 4) Canal Master instrumentation using Canal Master Resin blocks were sectioned, photographed, and evaluated the mean centering ratio and the mean area of dentin removed before and after the instrumentation. The results were as follows : I. the mean centering ratio 1. In the level 1 and level 3, there was no significant difference in the mean centering ratio. 2. In the level 2, Step-back technique showed the worst mean centering ratio among the tested groups(p<0.001) and there was no significant difference between the other three groups. 3. In the level 4, Canal Master instrumentation and Step-back technique showed better mean centering ratio than the other two techniques(p<0.001) and there was no significant difference between the two techniques. II. the mean area of dentin removed 1. In the level l and level 3, there was no significant difference in the mean area of dentin removed. 2. In the level 2, Canal Master instrumentation removed less dentin than the other three techniques(P<0.01). 3. In the level 4, Crown-down technique removed less dentin than the other three techniques(P<0.05).

• Journal of the Korea Society of Computer and Information
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• v.14 no.6
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• pp.59-64
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• 2009

Edge detection always influenced by the noise of original image, therefore need some methods to eliminate them in advance, and the Mean Shift algorithm has the smooth function which suit for this purpose, so adopt it to fade out the unimportant information and the sensitive noise portions. Above all, we use the Canny algorithm to pick up the contour of the objects we focus on. And, take tests and get better result than the former sole Canny algorithm. This combination method of Mean Shift algorithm and Canny algorithm is suitable for the edge detection processing.

• Journal of Environmental Science International
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• v.20 no.1
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• pp.107-118
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• 2011

While the assessment of mean flow field is very important to characterize the hydrodynamic aspect of the flow regime in river, the conventional methodologies have required very time-consuming efforts and cost to obtain the mean flow field. The paper provides an efficient technique to quickly assess mean flow field by developing and applying spatial averaging method utilizing repeatedly surveyed acoustic Doppler current profiler(ADCP)'s cross-sectional measurements. ADCP has been widely used in measuring the detailed velocity and discharge in the last two decades. In order to validate the proposed spatial averaging method, the averaged velocity filed using the spatial averaging was compared with the bench-mark data computed by the time-averaging of the consistent fix-point ADCP measurement, which has been known as a valid but a bit inefficient way to obtain mean velocity field. The comparison showed a good agreement between two methods, which indicates that the spatial averaging method is able to be used as a surrogate way to assess the mean flow field. Bed shear stress distribution, which is a derived hydrodynamic quantity from the mean velocity field, was additionally computed by using both spatial and time-averaging methods, and they were compared each other so as to validate the spatial averaging method. This comparison also gave a good agreement. Therefore, such comparisons proved the validity of the spatial averaging to quickly assess mean flow field. The mean velocity field and its derived riverine quantities can be actively used for characterizing the flow dynamics as well as potentially applicable for validating numerical simulations.

• Korean Journal of Veterinary Research
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• v.52 no.2
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• pp.141-146
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• 2012

Calving records of Holstein dairy cows from 2005 to 2010 comprising Goyang and Paju cities herd with 2,362 calving events representing 240 twin births were used to evaluate the effect of abomasal displacement and retained placenta after single or twin births on fertility. In retained placenta cows, the period of twin pregnancy (mean 270.5 days) was shorter than that of single pregnancy (mean 274.8 days), however first artificial insemination period (twin: mean 107.4 days, single: mean 92.0 days), non-pregnant period (twin: 154.8 days, single: 132.2 days), and number of insemination (twin: mean 2.00 times, single: mean 1.87 times) of twin pregnancy were increased as compared with single pregnancy. In abomasal displacement cows, first artificial insemination period (twin: mean 122.9 days, single: mean 106.0 days), non-pregnant period (twin: 172.4 days, single: 152.0 days), and number of insemination (twin: mean 2.16 times, single: mean 1.89 times) of twin pregnancy were increased as compared with single pregnancy. The prevalence of complication such as retained placenta, abomasal displacement with single or twin births increased first artificial insemination period, non-pregnant period, and number of insemination period.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1499-1513
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• 2014

This paper proposes a novel blind image watermarking scheme exploiting Block Truncation Coding (BTC). Most of existing BTC-based watermarking or data hiding methods embed information in BTC compressed images by modifying the BTC encoding stage or BTC-compressed data, resulting in watermarked images with bad quality. Other than existing BTC-based watermarking schemes, our scheme does not really perform the BTC compression on images during the embedding process but uses the parity of BTC quantization data to guide the watermark embedding and extraction processes. In our scheme, we use a binary image as the original watermark. During the embedding process, the original cover image is first partitioned into non-overlapping $4{\times}4$ blocks. Then, BTC is performed on each block to obtain its BTC quantized high mean and low mean. According to the parity of high mean and the parity of low mean, two watermark bits are embedded in each block by modifying the pixel values in the block to make sure that the parity of high mean and the parity of low mean in the modified block are equal to the two watermark bits. During the extraction process, BTC is first performed on each block to obtain its high mean and low mean. By checking the parity of high mean and the parity of low mean, we can extract the two watermark bits in each block. The experimental results show that the proposed watermarking method is fragile to most image processing operations and various kinds of attacks while preserving the invisibility very well, thus the proposed scheme can be used for image authentication.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.195-198
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• 2013

Recognition and Tracking of interesting object is the significant field in Computer Vision. Mean-Shift algorithm have chronic problems that some errors are occurred when histogram of tracking area is similar to another area. in this paper, we propose to solve the problem. Each algorithm blocks skin color filtering, face detect and Mean-Shift started consecutive order assists better operation of the next algorithm. Avoid to operations of the overhead of tracking area similar to a histogram distribution areas overlap only consider the number of white pixels by running the Viola-Jones algorithm, simple arithmetic increases the convergence of the Mean-Shift. The experimental results, it comes to 78% or more of white pixels in the Mean-Shift search area, only if the recognition of the face area when it is configured to perform a Viola-Jones algorithm is tracking the object, was 100 percent successful.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.79-85
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• 2019

In this paper, we propose a short-term power forecasting method by applying Long Short Term Memory (LSTM) and Gated Recurrent Unit (GRU) neural network to Internet of Things (IoT) power meter. We analyze performance based on real power consumption data of households. Mean absolute error (MAE), mean absolute percentage error (MAPE), mean percentage error (MPE), mean squared error (MSE), and root mean squared error (RMSE) are used as performance evaluation indexes. The experimental results show that the GRU-based model improves the performance by 4.52% in the MAPE and 5.59% in the MPE compared to the LSTM-based model.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.176-182
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• 2021

Objective: The purpose of this study is to investigate whether the athletic knee show greater rotation and translation movement than non-athletic knee during the treadmill walking with their preferred speed in a complete gait cycle. Method: Thirty young and healthy male subjects participated in the study, fifteen handball players (mean age: 19.6 ± 1.4 years old, mean weight: 85 ± 11.9 Kg, mean height: 179.8 ± 4.7) and fifteen non-athletes (mean age: 22.8 ± 1.2 years old, mean weight: 74.5 ± 8.6 Kg, mean height: 175 ± 5.9). Three-dimensional positional coordinate of lower limb during treadmill walking were analyzed. Results: There were significant differences (t (22.014)=1.585, p=0.127 in the range of internal and external rotation with mean value for handball player (M=14.4513, SD=2.3839) was higher than non-athletes (M=13.3327, SD=1.337). The magnitude of the difference in the means (mean difference=1.11867, 95% CI: -0.34489 to 2.5822) was significant. There were also significant differences (t (17.956)=1.654, p=0.116 in the max abduction and adduction with mean value for handball player (M=5.7160, SD=2.49281) was higher than non-athletes (M=4.5773, SD=0.94667). The magnitude of the difference in the means (mean difference=1.138, 95% CI: -0.30805 to 2.58539) was significant. At significance level 0.05. Conclusion: Finding of this study suggest that to understand the actual characteristic of knee motion studies have to be done in different walking and running trial at variable speed.

• Survey Research
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• v.7 no.2
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• pp.53-69
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• 2006

Weights can be made and imposed in both sample design stage and analysis stage in a sample survey. While in design stage weights are related with sample data acquisition quantities such as sample selection probability and response rate, in analysis stage weights are connected with external quantities, for instance population quantities and some auxiliary information. The final weight is the product of all weights in both stage. In the present paper, we focus on the weight in analysis stage and investigate the effect of such weights imposed on the weighted mean when estimating the population mean. We consider a finite population with a pair of fixed survey value and weight in each unit, and suppose equal selection probability designs. Under the condition we derive the formulas of the bias as well as mean square error of the weighted mean and show that the weighted mean is biased and the direction and amount of the bias can be explained by the correlation between survey variate and weight: if the correlation coefficient is positive, then the weighted mein over-estimates the population mean, on the other hand, if negative, then under-estimates. Also the magnitude of bias is getting larger when the correlation coefficient is getting greater. In addition to theoretical derivation about the weighted mean, we conduct a simulation study to show quantities of the bias and mean square errors numerically. In the simulation, nine weights having correlation coefficient with survey variate from -0.2 to 0.6 are generated and four sample sizes from 100 to 400 are considered and then biases and mean square errors are calculated in each case. As a result, in the case or 400 sample size and 0.55 correlation coefficient, the amount or squared bias of the weighted mean occupies up to 82% among mean square error, which says the weighted mean might be biased very seriously in some cases.