• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.1
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• pp.44-49
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• 2003

Masan Bay is one of the most heavily polluted bay in Korea owing to the large industrial complex and urban area. Water transparency, Secchi depth in meter, was observed 33 times totally at four sites during 1995 through 2002 and analysed statistically. The range was 0.2∼7.2m, mean 204m, and variation coefficient 60% in totally. Roughly speaking, monthly mean showed lower value April or July than other months. Seasonal mean showed lower in spring or summer than other seasons. Yearly mean was lowest in '95 and '98 during 7 years. Each sampling site showed a different patterns by the monthly, seasonal or yearly transparencies. Inner bay area, S1 site, showed lowest transparency and highest variation coefficient owing to the streamlets and urban area. And it was supposed that one of the important factor affecting different transparency distribution of most seaward site, S4 site, among four sites in the Masan Bay may be the underwater effluents of urban sewage water treated.

• Magazine of the Korean Society of Agricultural Engineers
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• v.23 no.4
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• pp.46-52
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• 1981

The aim at this study has the stochastic hydrological analysis for the annual mean discharge and monthly discharge which were observed at Lobith of River Rhine in the Netherlands from 1901 to 1972. After this study was analysed by computer IBM 370 and Hewlett Parkard 9800, the results were as follows; 1.When 72 data was divided into two groups of subsample data as 36 data, they do not have their properties to be non-homogeneous and inconsistent due to F-test and t-test. 2.The credit limits of the serial correlation coefficient was fluctuated $\pm$0. 231 which was shown in Fig. 3. at significant level 99% by Anderson's test. 3.The correlogram at short term was shown to be no short-term persistence as Fig. 3. 4.Since the correlogram at long term has displayed that Hurst's coefficient was 0.6144 between 0.6 and 0.7, it was to be no long-term persistence. 5.The stochastic model with annual discharge of this River Rhine was shown with $\chi$t=2195+483. 8 $\varepsilon$t as $\chi$t=$\mu$+oet and $\varepsilon$t=$_1$ø$\varepsilon$t-$_1$+ζt where t=1,2,3,..., ζt is an independent series with mean zero and variance (1-ø2), $\varepsilon$t is the dependent series, and 4' is the parameter of the model. 6.The serial correlation coefficient of monthly discharge was explained as $\chi$$_1$ = 0.34 . sin(6-$\pi$t+$\pi$) as Fig.4. and the River Rhine has no large fluctuation and smoothly changed during that time.

• Journal of Korean Academy of Nursing
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• v.10 no.2
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• pp.73-85
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• 1980

The purpose of this study was to investigate the compliance behavior of hypertensive patients in light of their health belief model that explains an individual's compliance with health maintenance or getting well. Although there are many effective regimens and treatments for hypertension nowadays. the most important point to be taken to consideration in their behavioral aspect is their compliance with regard to the control of body weight. eating habits as to salt and cholesterol intake. stresses. activity patterns and smoking as related to their life style. The important reasons for the failure in the control of hypertensive patients are the complexity of regimens to be complied to. irregular medication and the life long restrictions in their own life style. The compliance of patients to medical regimens and rocommendations or failure to do so is an essential factor. Accordingly. the degree of the patient's compliance is an important determinant as to the success or failure of hypertension control. The subjects for this study were 187 hypertensive patients selected from admitted and out patients of the medical department at seven University Hospitals in Seoul. Data was collected from Dec. 1, 1979 to Feb. 15, 1980 using the questionaire method and was analysed by the use of means. standard deviations, coefficient of correlations, analysis of variance and multiple regression analysis. The results obtained are as follows A. Of the seven independent variables in light of health belief model. benefit. barrier and severity are closely related to patient's compliance behavior. Therefore these variables could be used as determinants to predict and modify the hypertensive behavior. 1. Benefit is the most important and significant of the variables for explaining the dependent variables. It accounts for the highest variance of patient's compliance. (23.62%) 2. Then taking the former together with barrier. the variance of compliance showed on increase. (26.59%) 3. And with the addition of severity to the first two. the variance of compliance was also increased. (28.l2 %) B. Except for susceptibility all the independent variables such as severity. benefit, knowledge. motivation and barrier are correlated to dependent variable compliance. C. Sex. marital status and religion appeared to have significant influence on the dependent variables. Therefore one could conclude that the more the patients are aware that hypertension is a threat to health. the more they understand the benefit of taking actions to prevent such a threat. and the less they perceive any barrier when taking action. the more compliant they become in following medical regimens and recommendations. Age. marital status and religion played a significant influence to their compliance. Accordingly. the selected structural variables and demographic variables which have influenced sick role behavior of the hypertensive patient must be integrated to teaching and counselling programs for better hypertension control.

• Journal of the Korean Chemical Society
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• v.42 no.6
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• pp.646-651
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• 1998

The molecular structure of sulfur compounds and the retention relationship are studied by gas chromatography. Analyzed sulfur compounds are, hydrogen sulfide, sulfur dioxide, carbon disulfide, ethyl mercaptan, dimethyl sulfide, iso-propyl mercaptan, normal propyl mercaptan, ethyl methyl sulfide, tert-butyl mercaptan, tetrahydrothiophene, thiophene, and 2-chlorothiophene. Multiple linear regression explains the retention relationship of molecular descriptors. In GC the temperature program is 30$^{\circ}C$ held for 10.5 min, and then increased to 150$^{\circ}C$ at a rate 15$^{\circ}C$/min. Predicted equation for relative retention time (RRT) using SAS program is as follows; $RRT=0.121bp+14.39dp-8.94dp^2+0.0741sqmw-35.78\; (N=8,\; R^2=0.989, \;Variance=0.175,\;F=66.21)$. RRTs are function of boiling point, the square root of molecular weight, molecular dipole moment, and boiling point effects mostly on RRT. The RRT is maximized at the molecular dipole moment of 0.805D, when using nonpolar columns. The planar and highly symmetric compounds are eluted slowly. The square, of correlation coefficient $(R^2)$ using SAS program, is 0.989, and the variance is 0.175 in training sets. For three sulfur compounds, the variance between observed RRTs and predicted RRTs is 0.432 in testing sets.

• Journal of Biosystems Engineering
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• v.21 no.2
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• pp.155-166
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• 1996

A direct injection sprayer was designed using the concepts of injection mixing and total flow control, flowrate-based system compensating for the variation of forwarding speed. A metered rate, proportionally to the actual diluent flow rate, of a tracer chemical was injected directly into the diluent stream. The injection of chemical may improve the precision and safety of chemical application process. The control system was evaluated for the variables of the control interval, tolerances and sensitivities of flow regulation valve and injection pump. Performance of the system was assessed as that the response time of flow rate, response time of injection rate, absolute steady state error, and the coefficient of variance(C.V.) of concentration were 8.5 and -0.53 seconds, 0.067 lpm(0.8%) and 3.15%, respectively, at optimal parameters of control interval of 1.0 sec, fast sensitivity of flow regulation valve, medium sensitivity of injection pump and medium tolerance of flow rate. Performance of the system can be improved by increasing the sensitivity of flow regulating valve and employing a high resolution velocimeter, such as Doppler radar.

• Computers and Concrete
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• v.30 no.1
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• pp.33-42
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• 2022

Experimentally predicting the compressive strength (CS) of concrete (for a mix design) is a time-consuming and laborious process. The present study aims to propose surrogate models based on Support Vector Machine (SVM) and Gaussian Process Regression (GPR) machine learning techniques, which can predict the CS of concrete containing nano-silica. Content of cement, aggregates, nano-silica and its fineness, water-binder ratio, and the days at which strength has to be predicted are the input variables. The efficiency of the models is compared in terms of Correlation Coefficient (CC), Root Mean Square Error (RMSE), Variance Account For (VAF), Nash-Sutcliffe Efficiency (NSE), and RMSE to observation's standard deviation ratio (RSR). It has been observed that the SVM outperforms GPR in predicting the CS of the concrete containing nano-silica.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.279-284
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• 2000

The object of this paper is to evaluate the chip breakability using the experimental equation of surface roughness, which is developed in turning by an orthogonal array method. L$\sub$9/(3$^4$) orthogonal array method, one of fractional factorial design has been used to study effects of main cutting parameters such as cutting speed, feed rate and depth of cut, on the surface roughness. The evaluation of chip breakability is used the chip breaking index(C$\sub$B/), non-dimensional parameter. And the analysis of variance (ANOYA)-test has been used to check the significance of cutting parameters. Using the result of ANOYA-test, the experimental equation of chip breakability, which consists of significant cutting parameters, has been developed. The coefficient of determination of this equation is 0.866.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.257-261
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• 1997

Patents often serve as leading indicators of technological change. This patenting activity reflected R&D (Research & Development) of new technology. The purpose of this study is to set up a forecasting model that anticipate the number of domestic patent applications and the number of patents granted relating to R&D inputs (R&D expenditure, R&D manpower) at the level of three industrial sectors in Korea : electrical-electronic, machinery, chemical etc. In this study, forecasting models were used trend extrapolation and a set of regressions. Both Theil's inequality coefficient and MAE(Mean Absolute Error) were utilized to test the precision of predicted value. The patent data and the R&D data were based on Indicators of Industrial Technology data throught 1980 to 1996. The major results obtained in this study are as follows (1) The regression model is more useful for forecasting the trends of the number of patent applications and patents granted than the trend extrapolation method. (2) The variance of Theil's inequality is smaller in patent applications than in patent granted.

• Research in Community and Public Health Nursing
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• v.18 no.1
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• pp.23-31
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• 2007

Purpose: This study was to investigate factors influencing the well-being of the aged in rural areas. Method: The subjects consisted of 250 elders living in rural areas of Kyungsangbuk-do. Data were collected by questionnaire surveys using convenience sampling. The instruments used in this study were the Well-being Scale by Chang (1999), the perceived health status developed by Speake, Cowart, and Pellet (1989), and the Social Support Scale developed by Song (1991). Data were analyzed using the SPSS program through descriptive statistics, t-test, ANOVA, Duncan's multiple-range test, Pearson Correlation Coefficient and stepwise multiple regression. Results: The most powerful predictor of well-being was social support, and then religion, health status, living expenses, and habitation accounted for 42.95% of variance in the well-being of the aged in rural areas. Conclusion: These results suggest that perceived health status and social support can be potential risk factors in the well-being of the aged. The findings of this study provide the basis of program development to improve the well-being of the aged in rural areas.

• Korean Journal of Applied Biomechanics
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• v.27 no.2
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• pp.149-155
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• 2017

Objective: The purpose of this study was to investigate the effects of three visual conditions (eyes opened, eyes closed, and wearing of a head mounted display [HMD]) on single-leg standing through kinematics and kinetic analysis. Method: Twelve college students (age: $24.5{\pm}2.6years$, height: $175.0{\pm}6.4cm$, weight: $69.2{\pm}5.1kg$) participated in this study. The study method adopted three-dimensional analysis with six cameras and ground reaction force measurement with one force plate. The analysis variables were coefficient of variation (CV) of the center of body mass, head movement, ground reaction force, and center of pressure, which were analyzed using one-way analysis of variance with repeated measures according to visual conditions. Results: In most cases, the results of this study showed that the CV was significantly higher in the order of HMD wearing, eyes closed, and eyes opened conditions. Conclusion: Our results indicated that body sway was the largest in the HMD wearing condition, and the risk of falling was high owing to the low stability.