• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.5
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• pp.21-26
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• 2005

It is important to measure the rotational accuracy of NC lathe spindle as it affects to the qualities of all machines machined by the NC lathe using in industries. The bad rotational accuracy of NC lathe spindle are caused mainly by wearness of the spindle in using and quality of spindle when machining and using low level bearings. It occurs especially in case of NC lathes because the cutting force acting to work-piece act on one side to the spindle not to both sides symmetrically. Therefore in this study, constructing experimental appratus for measuring of rotational accuracy by using eddy current type gap sensors, converters, screw terminal, data acquisition board inserted in computer and software f3r data acquisition, DT VEE ver. 5.0 and then error data acquired in the rotational accuracy test of NC lathe spindle are analysed in plots and statistical treatments.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.43-48
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• 2007

It is important to measure the rotational accuracy of lathe spindle as it affects to the qualities of all machines machined by the lathe using in industries. The bad rotational accuracy of lathe spindle are caused mainly by wearness of the spindle in using and quality of spindle when machining and using low level bearings. It occurs especially in case of lathes because the cutting force acting to work-piece act on one side to the spindle not to both sides symmetrically. Therefore in this study, constructing experimental apparatus for measuring of rotational accuracy by using eddy current type gap sensors AEC5706PS and sensors, s-06LN, data acquisition board DT9834(USB type) and software for data acquisition, DT Measure Foundry ver. 4.0.7 etc., error data acquired in the rotational accuracy test of lathe spindle are analysed in plots and statistical treatments.

• Journal of Environmental Science International
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• v.27 no.10
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• pp.883-899
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• 2018

In this study, water quality data of eight main sites in the Geumho River watershed were collected and analyzed for long-term changes in water quality over the period from 2005 to 2015. The results showed that BOD concentration was gradually improved by the Total Maximum Daily Load (TMDL), stages 1 and 2. Recently, a tendency of increasing BOD concentration was observed in the downstream section of the river. The concentration of COD was analyzed to be contaminated throughout the water system regardless of the water quality improvement project, and the TN concentration tended to increase in the midstream of the river from 2013. The TP concentration has clearly decreased from 2012 after the second stage of TMDL. For the statistical analysis of PCA ordination, monthly water qualities (pH, DO, Electrical Conductivity (EC), Water Temperature (WT), BOD, COD, TN, TP, TOC, and SS) and flow rate data for 5 years from 2012 to 2016 were used. Seasonally the Geumho River showed an increase in the TN concentration at point sources during the dry season (December to February). TP showed the effect of non-point sources in the summer, because rainfall has caused a rise in flow rate in the upstream. Besides, the origin of pollution source was changed from non-point sources with BOD, COD, and TOC.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.225-231
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• 2002

POSCO $\#2$ Stainless steel making plant produces more than 600 thousand ton per year with a variety of products consisting of austenite and ferrite stainless steel to meet custrmers' needs since 1996. The plant has four different major processes, that are, EAF-AOD-VOD-CC to finally produce semi-product called as slab. In this study, we importantly took AOD process into consideration due to its roles such as to check and verify the final qualities through sampling inspection. But the lead-time from sampling to its verification takes five to ten minutes causing produrtivity loss as muck as the lead-time as a result. Of all indices for quality and process control the plant has, carbon ingredient in liquid type of steel is the most important since it affects in a great way to the characteristics of steel, if any problem. customers not satisfied with quality could issue a claim; therefore there is no way hut to guarantee it before delivery. in this study, to reasonably reduce lead-time ran save a cycle time and finally improve our productivity from a state-or-art alternative just such as applying statistical model based on multi-regression analysis into the A.O.D line by analyzing the statistical and technical relationship between carbon and the relevant some vital independent variables. In consequence, the model with R-square $87\%$ allowed the plant to predict, abbreviating the process in relations to sampling to verification. approximately the value of [C] so that operators could run the process line with reliability on data automatically calculated instead of actual inspection. In the future, we are going to do the best to share this type of methodology with other processes, if possible, to apply into them.

• Journal of the Korean Society of School Health
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• v.20 no.1
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• pp.25-35
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• 2007

Purpose: This study was to identify the types and characteristics of health problems of middle school students in Gangwondo. Methods: The subjects of the study were 11 middle schools from 47 schools with nurse teachers in Gangwondo. The anecdotal records of the school health clinics were collected from March to December in 1998 with the agreement of nurse teachers of the schools. Results: 71.0% of the middle students visited the school health care clinics once or more than once. The mean frequency of health problems was 2.03 times per one year. The rate of health problems did not show any statistical differences by sex, school location, age, the day of the week and weather. However, there were statistical differences of the rate by month. The highest rate was showed in September, followed by June and April (F=2.52, p=0.01). Health problems were classified into 11 types. Gastrointestinal illness showed the largest proportion (60.6%). The oral illness showed statistical differences among the location of school, between municipal and rural area (t=-2.97, p=0.016). There were 411 types of signs and symptoms recorded. Among them, headache was showed the highest proportion with 2,122 cases (11.2%). Conclusion : The incidence rate of health problems was higher than that of earlier studies. It showed that the incidence rates and the types of diseasps in middle school students were different by school locations, characteristics of students, and months. To improve the qualities of primary cares in school health services, the reformed and unified anecdotal record system and the standardized guidelines for primary care are necessary.

• Journal of Wetlands Research
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• v.14 no.1
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• pp.11-20
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• 2012

The aim of this study is to accumulate the data about the roof-harvested rainwater quality characteristics for the better rainwater management. According to the results of rainwater quality indicators (pH, COD, TSS, T-N, T-P, $NH_4$-N, $NO_3$-N, enteric bacteria, heterotrophs, Pb, Cd, Cu), the rainwater qualities of the first flush of roof-harvested was the most polluted about 2 or 3 times (more than 100 times in microbial contamination) compared to the qualities of directly collected rainwater. In the first 10 min flush, over the 60% amounts of contaminant were released from the roof during 30 minute rainwater monitoring. Through statistical factor analysis, relatively close items(variables) can be categorized. It is expected that the continuous monitoring of the roof-harvested rainwater will help to design the safe and economical rainwater storage system in Korea.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.141-144
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• 2006

Though this study examines closely relation of sphere school register special qualities and participation degree, participation motive and mind health that is society based on person and model virtue study finding and the construction enemy about study of effect, woman's. swimming participation and mind satisfaction which exercise gets in company employee's mind health in the morning before attendance positively, there is main purpose. The subject who answered to given questionaire was 298 persons. To analyze collected data, used statistical technique statistical analysis technique anova analysis. Through such method of study and formality, this study deduced following result. First, adult woman's participation among by thing which participation frequency was mind health and difference that keep in mind statistically. Second, adult woman's participation among by thing which participation period was mind health and difference that keep in mind statistically Third, adult woman's participation among by thing which participation strength was mind health and difference that keep in mind statistically.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.469-479
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• 2015

This study have been conducted to analyze the feasibility of establishing Contamination Warning System(CWS) that is capable of monitoring early natural or intentional water quality accidents, and providing active and quick responses for domestic C_water supply system. In order to evaluate the water quality data set, pH, turbidity and free residual chlorine concentration data were collected and each statistical value(mean, variation, range) was calculated, then the seasonal variability of those were analyzed using the independent t-test. From the results of analyzing the distribution of outliers in the measurement data using a high-pass filter, it could be confirmed that a lot of lower outliers appeared due to data missing. In addition, linear filter model based on autoregressive model(AR(1) and AR(2)) was applied for the state estimation of each water quality data set. From the results of analyzing the variability of the autocorrelation coefficient structure according to the change of window size(6hours~48hours), at least the window size longer than 12hours should be necessary for estimating the state of water quality data satisfactorily.

• Culinary science and hospitality research
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• v.16 no.3
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• pp.188-204
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• 2010

This research aims at finding relationship marketing factors that have positive effects on customer long-term orientation concerning wine purchasing personnels of domestic dinging companies such as sommeliers and managers. By figuring out the qualities of relationship such as the roles of trust and commitment while long-term orientation is being developed, it also tries to help wine suppliers which have been having a hard time due to domestic market recession and tight competition develop marketing strategies for promotion. A survey of wine purchasing personnels and sommeliers who work for fine dining restaurants, casual dining restaurants and wine bars was conducted for 30 days from Jan. 15, 2010 to Feb. 13, 2010. The statistical packages of SPSS 15.0 statistical package and AMOS 7.0 ver were used to perform frequency analysis, reliability test, confirmatory factor analysis, and path analysis. The result shows that among relationship marketing factors, communication and seller expertise have a positive impact on long-term orientation through trust and affective commitment.

• Journal of the Korean Society of Food Culture
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• v.22 no.1
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• pp.22-31
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• 2007

The purpose of this study was to analyze evaluation variables of service quality of Korean restaurant especially focused on cold noodle restaurants(CNR). The data were analyzed about customer’s expectation of food service quality, service quality was improved by employee’s service in restaurant and employee education in the focus on CNR. The survey was carried out 423 customers and 50 employees in Seoul and Kyunggi province. All statistical data analyses were conducted using the Statistical Package for the Social Science(SPSS version 10.0). The consumer’s evaluation score of service quality were significantly different by consumer’s characteristics. The well planned service at CNR must be developed according to consumer variables such as sex and age group. The evaluation score of service quality were not significantly different by seasonal variation and consumer’s menu selection. The evaluation score of service qualities in CNR were significantly different between customer variables with employees variables. All of the evaluation points of service quality in employees were significantly higher than customers. This result was show that well-trained employees were important factors in consumer satisfaction. Through the employee education program, consumer oriented service mind mort be to developed in employees and employees’ recognition about the importance of service increased the satisfaction of customer using CNR.