• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.5
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• pp.272-278
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• 2023

Attention, an important element of human cognitive function, is an important cognitive function that focuses only on necessary stimuli from various stimuli through sensory systems. Although various studies have shown that environmental conditions may affect the level of attention, the effect on attention by applying cooling directly to the skin has not been studied much. Differences in attention depending on when and whether cryotherapy was applied during learning and relaxation activities were examined among 36 subjects. The FAIR attention test, a visual attention evaluation tool, was used, and statistical analysis was conducted on the results of the sub-index of FAIR: Performance index, Quality index, and Continuity index. Among participants who performed rest activities, the application of cryotherapy appeared to have no effect on any subindex. Among the participants who performed learning activities, the group that applied pre-cryotherapy (P=469.0, C=435.4)) and the group that applied post-cryotherapy (P=457.4, C=425.4) showed higher Performance index and Continuity index than the group that did not apply cryotherapy (P=335.8, C=301.7). From these results, it can be concluded that cryotherapy maintains the level of alertness and awakens attention, albeit to a limited extent.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.336-343
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• 2003

Two types of statistical models, simple and multivariate log linear models, were studied for continuity simulation and trend analysis of water qualities in incoming flows to Lake Paldang. Water quality is a function of one independent variable (flow) in the simple log linear model, and of three different variables (flow, time, and seasonal cycle) in multivariate model. The independent variables act as surrogate variables of water quality in both models. The model coefficients were determined by the monthly data. The water qualities included 5-day Biochemical Oxygen Demand ($BOD_5$), Total Nitrogen (TN), and Total Phosphorus (TP) measured from 1995 to 2000 in the South and the North branches of Han River and the Kyoungan Stream. The results indicated that the multivariate model provided better agreements with field measurements than the simple one in a31 attempted cases. Flow dependency, seasonality, and temporal trends of water quality were tested on the determined coefficients of the multivariate model. The test of flow dependency indicated that BOD concentrations decreased as the water flow increased. In TN and TP concentrations, however, there were no discernible flow effects. From the temporal trend analyses, the following results were obtained: 1) no trends on BOD at all three upstreams, 2) increase on TN at the South Branch and the Kyoungan Stream, 3)decrease on TN at the North Branch,4) no trends on TP at the North and the South Branches and 5) increase on TP at the Kyoungan Stream by 3 to 8% per years. The seasonality test showed that there were significant seasonal variations in all three water qualities at three incoming flows.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.146-156
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• 2010

The objective of this study was to improve the accuracy of calculation and estimation of solar radiation and duration of sunshine, which are the most important variables of photovoltaic power generation in deciding the location of photovoltaic facilities efficiently. With increasing interest in new and renewable energies, research on solar energy is also being conducted actively, but there have not been many studies on the location of photovoltaic facilities. Thus, this study calculated solar duration and solar radiation based on geographical factors, which have the most significant effect on solar energy in GIS environment, and corrected the results of analysis using diffuse radiation. Moreover, we performed ordinary kriging, a spatial statistical analysis method, for estimating values for parts deviating from the spatial resolution of input data, and used variogram, which can determine the spatial interrelation and continuity of data, in order to estimate accurate values. In the course, we compared the values of variogram factors and estimates from applicable variogram models, and selected the model with the lowest error rate. This method is considered helpful to accurate decision making on the location of photovoltaic facilities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1477-1484
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• 2015

This paper proposes a robust method for object tracking based on Kalman filters algorithm and covariance matrix. As a feature of the object to be tracked, covariance matrix ensures the continuity of the moving target tracking in the image frames because the covariance is addressed spatial and statistical properties as well as the correlation properties of the features, despite the changes of the form and shape of the target. However, if object moves faster than operation time, real time tracking is difficult. In order to solve the problem, Kalman filters are used to estimate the area of the moving object and covariance matrices as a feature vector are compared with candidate regions within the estimated Kalman window. The results show that the tracking rate of 96.3% achieved using the proposed method.

• 한국가시화정보학회:학술대회논문집
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• 2003.11a
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• pp.39-42
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• 2003

Leading edge extension(LEX) in a highly swept shape applied to a delta wing features the modern air-fighters. The LEX vortices generated upon the upper surface of the wing at high angle of attack enhance the lift force of the delta wing by way of increased negative suction pressure over the surfaces. The present 3-D stereo PIV includes the Identification of 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system, removal of error vectors by a statistical method followed by a continuity equation criterion and so on. A delta wing model with or without LEX was immersed in a circulating water channel. Two high-resolution, high-speed digital cameras$(1280pixel\times1024pixel)$ were used to allow the time-resolved animation work. The present dynamic stereo PIV represents the complicated vortex behavior, especially, in terms of time-dependent characteristics of the vortices at given measuring sections. Quantities such as three velocity vector components, vorticity and other flow information can be easily visualized via the 3D time-resolved post-processing to make the easy understanding of the LEX effect or vortex emerging and collapse which are important phenomena occurring in the field of delta wing aerodynamics.

• Journal of Preventive Medicine and Public Health
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• v.7 no.2
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• pp.395-401
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• 1974

In order to figure out the normal range, lower limit of hypertension and upper limit of hypotension of the blood pressure of Korean, authors had measured blood pressure according to Korotkow's method for 31,897 healthy persons as samples who were occupied different levels of the social class except cases who would seem to be the essential hypertension and had the diseases affecting to secondary hypertension. A following conclusion was induced by actual measurement and statistical reasoning. 1. The normal range and limits of hypo- and hypertension by sex and age groups of Korean were demonstrated in Table 1 and Figure 1. 2. The more aging the higher value of blood pressure in both sexes, especially women rather than men and systolic as to diastolic. 3. Generally, blood pressure values of female were lower than male, after 55 years of age, however, the crossing phenomenon was recognizable. 4. To settle the normal and abnormal ranges of the blood pressure of Korean, it was attempted that $M{\pm}1.282{\sigma}$ as normal range, $M+2{\sigma}$ as lower limit of hypertension and $M-2{\sigma}$ as upper limit of hypotension were calculated, and regression lines were drawn to adjust the biological variables and derive continuity from each age class. (Fig. 2 and 3) 5. The blood pressure levels were becoming elevated as to getting increased of the body weight, particularly diastolic value at 40-49 age group in male and systolic value at 30-39 age group in female.

• Journal of Technologic Dentistry
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• v.32 no.3
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• pp.211-220
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• 2010

Purpose: The purpose of this study was to analyze dental laboratory's working environment and turnover intention level and to examine its correlation. Methods: 180 dental technicians in Seoul, Incheon, and Chungnam area were selected. Survey was carried out from April 6, 2009 to May 20, 2009 by using self-administered questionnaire. As for the tools for this study, the structured questionnaire was used with its proven reliability and feasibility, and the contents of questionnaire consisted of 43 questions on the basis of related references. The questionnaire consisted of total 32 questions which included general attribute of subjects(14 questions), working Environment(20 questions) and turnover intention(9 questions). The data analysis was processed by computerized system with SPSS 12.0. Statistical analysis techniques included frequency, percentage, T-test, F-test analysis and regression analysis. Results: As a result of analyzing the research subjects' working environment level, there was significant difference in the item of health(P<0.05). The average in the working environment was indicated to be high with 1.53. As a result of analyzing the research subjects' turnover intention level, there was difference in the item of working hours a day(Hour), job satisfaction level, plan for task continuity, most difficulty given task(P<0.05). The average of turnover intention was indicated to be high with 2.85. Conclusion: Correlation between working environment and turnover intention, most of variables were indicated to have reverse correlation, thereby having been shown that the worse working environment leads to the more turnover intention.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.132-143
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• 2017

It is essential to obtain periodic sediment discharge data in a river in order to minimize problems that may arise from the erosion, transport, and deposition of sediment. However, it is difficult to estimate sediment discharge by the sediment discharge measurement plan in Korea at present, and empirical fomulas or numerical models are used to replace them. This paper has applied the K-DRUM model, a grid-based rainfall-runoff-sediment model, to estimate sediment discharge and ensure the continuity of the data in the watershed. Discharge and sediment load in 17 watersheds were estimated and the applicability of the model was analyzed through comparisons with measured data. For quantitative evaluation, NSE, PBIAS and RSR items were used, and discharge results reflected the tendency of rainfall and showed high statistical value. In case of sediment discharge, the soil erosion process of the watershed is physically well reflected. When the calibration was performed using the measure data, the applicability seems to be excellent in estimating the continuous sediment discharge data in the real watershed.

• Korean Journal of Social Welfare
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• v.35
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• pp.205-229
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• 1998

Although experts have called for increased collaboration between families and school systems, the actual programs for such efforts were not introduced. Thus, this study attemps to develop school-based parent education program for home-school collabration. PEP was developed through the circular process, which consist of planning, design, enactment, and evaluation. The group process of PEP was analyzed qualitatively and the effectiveness of outcomes was examined by nonparametric statistical analysis. Two factors contributed to success of PEP were as follows: 1) Increased homogenities, such as children's developmental stage, same school enrollment, and sense of community belongingness. 2) Consistency and continuity between PEP and Mental Health Prevention Program for students. Through the PEP based on these factors, parents' strong commitment was established and tangible results such as increased knowlege and fluent coping skills regarding children's problematic behaviors were found. Implications for home-school collaboration were explored, as are recommendations for how PEP can be prepared to link between families and schools.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.103-110
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• 2008

A reliable extraction of welded area is the precedent task before the detection of weld defects in industrial radiography. This paper describes an attempt to detect and extract the welded features of steel tubes from the computed radiography(CR) images. The statistical properties are first analyzed on over 160 sample radiographic images which represent either weld or non-weld area to identify the differences between them. The analysis is then proceeded by pattern classification to determine the clustering parameters. These parameters are the width, the functional match, and continuity. The observed weld image is processed line by line to calculate these parameters for each flexible moving window in line image pixel set. The local statistic line-clustering method is used as the classifier to recognize each window data as weld or non-weld cluster. The sequential procedure is to track the edge lines between two distinct regions by iterative calculation of threshold, and it results in extracting the weld feature. Our methodology is concluded to be effective after experiment with CR weld images.