• Journal of Information Technology Applications and Management
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• v.28 no.4
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• pp.21-32
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• 2021

In this study, factors affecting undergraduate students' dropout intentions consisted of aptitude and career fit of student's major, employement prospects of student's major, and graduation attitude were presented in the structural equation model and the moderating effect of academic year on the path coefficeint presented in the research model was verified. Undergraduate students are grouped into senior year (3rd and 4th grades) and junior year(1st and 2nd year) by the year in the university, As a result of analyzing 454 undergraduate students (105 in the junior group and 349 in the senior group), it was found that graduation attitude had a negative (-) effect on the dropout intention in both junior and senior group. The effect of employment prospects, and major aptitude and career firt on graduation attitude was not found in the junior group. However, in senior group, the effect of employment prospects, and major aptitude and career firt on graduation attitude was found to have a positive (+) effect, indicating that moderating effect of academic year does exist.

• The Korean Journal of Zoology
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• v.12 no.4
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• pp.109-113
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• 1969

Exeriments were carried out to determine the effect of age on the functional response of the predator, Podisus maculiventris reared on the different prey size of Hyphantria cunea in simple vial, twice at the 1st and 2nd generations of Hyphantria cunea. 1. Larvae ingested about 11.23, 18.4 and 20.7mg for each diet level (cf, table 1 to 3)in 2nd instar, 12.3, 23.37 and 28.3mg in 3rd instar, 18.17, 40.3 and 42.7mg in 4th instar, 51.7, 92.7 and 130.2mg in 5th instar for each diet level. 2. Adult males ingested about 528, 740, 545.1mg and females about 516.5, 627.5, 603.3mg in their whole life for each diet level. 3. The relationship between observed and predicted values, established by regression analysis was revealed as 0.80 to 0.91 in correlation coefficient.

• The Journal of the Korea Contents Association
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• v.12 no.8
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• pp.300-309
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• 2012

The purpose of this study was to understand about the influence of female undergraduates health behavior and health state upon sociality and the influence of sociality upon college life satisfaction. The subjects were 335 female junior-college students with major related to public health in Busan, Daegu, and Gyeongnam and were carried out questionnaire survey on general characteristics, sociality, college life satisfaction, health behavior, health status, and internet addiction. An analytical method was made through chi-square test, t-test, one-way ANOVA, ANOVA for trend, and structural equation modeling(SEM). As a result, the influence of accountability had the greatest influence as sub-factor. Accountability and age had a positive correlation(p<0.001). Accountability was low when self-cognitive body shape was very thin(p=0.005). In sociality, full age(p<0.001), self rated health(p<0.001), and physical education instruction for the 3rd grade of high school(p=0.004) showed direct effect. Also, sociality showed direct influence upon college life satisfaction. The older age, the higher self rated health, and the more instruction for the 3rd grade of high school led to the higher sociality, thereby having been indicated to be higher in college life satisfaction. Accordingly, a multi-dimensional effort is judged to be necessary for reinforcing physical education activity for high school students and for improving their quality of life as a plan for increasing college life satisfaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.608-616
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• 2018

If a general nonlinear system is linearized by the successive multiplication of the 1st and 2nd order systems, then there are four types of poles in this linearized system: the pole of the 1st order system and the equal poles, two distinct real poles, and complex conjugate pair of poles of the 2nd order system. Linear Quadratic (LQ) control is a method of designing a control law that minimizes the quadratic performance index. It has the advantage of ensuring the stability of the system and the pole placement of the root of the system by weighted matrix adjustment. LQ control by the weighted matrix can move the position of the pole of the system arbitrarily, but it is difficult to set the weighting matrix by the trial and error method. This problem can be solved using the characteristic equations of the Hamiltonian system, and if the control weighting matrix is a symmetric matrix of constants, it is possible to move several poles of the system to the desired closed loop poles by applying the control law repeatedly. The paper presents a method of calculating the state weighting matrix and the control law for moving the equal poles with Jordan blocks to two real poles using the characteristic equation of the Hamiltonian system. We express this characteristic equation with a state weighting matrix by means of a trigonometric function, and we derive the relation function (${\rho},\;{\theta}$) between the equal poles and the state weighting matrix under the condition that the two real poles are the roots of the characteristic equation. Then, we obtain the moving-range of the two real poles under the condition that the state weighting matrix becomes a positive semi-finite matrix. We calculate the state weighting matrix and the control law by substituting the two real roots selected in the moving-range into the relational function. As an example, we apply the proposed method to a simple example 3rd order system.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.3 s.43
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• pp.33-42
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• 2005

Frequency domain Volterra model is applied to nonlinear parameter identification procedure for dynamic systems modeled by nonlinear function. The frequency domain Volterra kernels, which correspond io linear, quadratic, and cubic transfer functions in lime domain, are incorporated in nonlinear parametric identification procedure. The nonlinear transfer functions, which can be derived from the Volterra series representation of the nonlinear differential equation of the system by Schetzen's method(1980), are directly used for modeling input output relation. The error is defined by the difference between the observed output and the estimated output which is calculated by substituting the observed input to nonlinear frequency domain model. The system parameters are searched by minimizing the error. Volterra model guarantees enough accuracy and convergence and the estimated coefficients have a good agreement with their actual values not only in the linear frequency region but also in the legion where the $2^{nd}\;or\;3^{rd}$ order nonlinearity is dominant.

• The Korean Journal of Pesticide Science
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• v.18 no.3
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• pp.175-180
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• 2014

This study was carried out to determine the economic injury level and economic threshold level on beet (Beta vulgaris L.) infested with Spoladea recurvalis in the plastic greenhouse condition in 2010. The second instar larvae of S. recurvalis were inoculated with 7 different density levels on the each 10 beet plants as a replication. Injury levels of beet leaves and density of S. recurvalis were increased with the inoculation density of S. recurvalis. However, yield and marketable commodity of beet were decreased. Linear relationship between the percent yield reduction (Y) of beet leaves and different infestation densities of S. recurvalis (X) was estimated by the following equation Y = 1.226x + 3.36. Based on the relationships between the densities of S. recurvalis larvae and yield index of beet leaves, the number of second instar larvae which caused 5% loss of yield, economic threshold level was estimated as 1.1 larvae/10 plants for the planting 10 days. The percent yield reduction (Y) of beet roots infested with different densities of S. recurvalis (X) estimated by the following equation Y = 1.537x + 1.4634 after inoculation for 10 days at 3rd harvesting of leaves. Based on the relationships between the densities of S. recurvalis larvae and yield index of beet roots, the number of second instar larvae which caused 5% loss of yield, economic threshold level was estimated as 6.4 larvae/10 plants for the planting 10 days.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.1 s.20
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• pp.49-58
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• 2006

Rainfall-runoff characteristics are analysed based on the geomorphological instantaneous unit hydrograph(GIUH) derived by geomorphological parameters using geographical information system in watershed ungaged or deficient of field data. Observed data of Seom river experiment watershed at upstream of Hoengseong dam and variable slope method for hydrograph separating of direct non are used. The 4th stream order of Seom river experimental watershed is developed with a regular correlation referred to the Horton-Strahler's law of stream order. The characteristic velocity to determine shape parameter of GIUH is 1.0m/s and its equation is modified for accurate results. Hydrograph at the outlet of 4th stream order of Maeil gage station and at the outlets of 3rd stream order of Sogun and Nonggeori gage stations show a little differences in falling limb of hydrograph but agree well to the observed data in general. The results by hydrological routing with HEC-HMS to the outlet of 4th stream order of Maeil gage station which the hydrograph by GIUH obtained at Sogun and Nonggeori gage stations of 3rd stream oder are applied as upstream inputs give better agreement with observed data than those by hydrograph by GIUH obtained at Maeil gage station of 4th stream order. In general, the rainfall-runoff by GIUH has applicability to the watershed routing of ungaged project regions.

• Korean journal of applied entomology
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• v.12 no.3
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• pp.109-114
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• 1973

In order to use the red wood ants (Formica sp.) as a resources of natural enemy of pine caterpillar (Dendrolimus spectabilis Butler), the distribution of red wood ants in Gyeongnam Province, general ecology, and the limit of transplantation was investigated. The results obtained were summarized as follows: 1. Red wood ants preyed upon 1st to 3rd instar of pine caterpillar. 2. Red wood ants were distributed to 474 locations of 18 county, covering 7,702, $559m^2$ in Gyeongnam Province. 3. The distribution of red wood ants was $60\%$ in lower part, $39.5\%$ in middle part and $0.5\%$ in upper part of the mountain. 4. It seems that the height of building nest was directly proportional to the total number of each colony, showing the regression equation of Y=6,200 X-27,813, and the building nest was concerned with soil moisture. 5. It was possible to transplant the red wood ants from May to September, md 5 nests were built by the transplanted ants within one year.

• Health Policy and Management
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• v.15 no.3
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• pp.60-78
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• 2005

The main objective of this study is to define the nature of the patient service quality of Health Centers, and based on that, to examine the causal relationship of Health Center visitor's perceived service quality with overall satisfaction, intention to revisit and intention to recommend. Data are collected on the basis of the second field survey of '3rd Regional Health Care Planning' operated by the Ministry of Health and Welfare(MOHW). In this study, the 24 patient satisfaction questions are used as outcome indicators. The samples are 3,091 patients who visited 68 Health Centers. The reliability and validity of patient service quality items was evaluated. Finally, the Structural Equation Modeling(SEM) analysis was conducted to find a causal relationship of service quality, patient satisfaction, intention to revisit and intention to recommend. This study shows firstly, the dimension of patient service quality was categorized into 3 dimensions, that is, facilities and environment, staff kindness, and convenience of utilization process. Secondly, the reliability and validity of patient service quality items was satisfied. Lastly, the total effect of convenience of utilization process factor on satisfaction(path coefficients=1.721), intention to revisit(0.843) and intention to recommend(0.696) is more higher than other variables. These findings imply that the quality of various services concerning convenience of utilization process at Health Centers should be improved to satisfy the health need of community people and improve the service quality of Health Centers.

• Journal of Environmental Science International
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• v.25 no.5
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• pp.737-744
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• 2016

For electrolysis process using an insoluble electrode, electrochemical performance was greatly affected by the manufacturing method and procedure, such as the firing temperature, pre-treatment, type of precursor solution, coating method, electrode material, etc. Components of the electrode therein is one of the most important factors in electrochemical reaction. To achieve such characteristics, a appropriate ratio of the electrode material should be carefully chosen. The aim of this research was to apply experimental design method in the optimization of electrode component for the maximum generation of oxidants in electrochemical oxidation process. Mixture design, especially expanded simplex lattice design, in DOME (design of mixture experiments) with Design Expert - commercial software - was used to analyze the data. Analysis of variance (ANOVA) showed a high coefficient of determination ($R^2$) value of 0.9470, thus ensuring a satisfactory adjustment of the $3^{rd}$ order special cubic regression model with the experimental data. The application of response surface methodology (RSM) yielded the following regression equation, which is an empirical relationship between the TRO generation concentration and independent variables(mol ratio of 3 electrode components) in a real unit: TRO generation concentration $(mg/L)=TRO\;conc.=98.25{\times}[Ir]+49.71{\times}[Sn]+95.29{\times}[Sb]-16.91{\times}[Ir]{\times}[Sn]-29.47{\times}[Ir]{\times}[Sb]-22.65{\times}[Sn]{\times}[Sb]+703.19{\times}[Ir]{\times}[Sn]{\times}[Sb]$. The optimized formulation of the 3 component electrode for an high TRO (total residual oxidants) generation was acquired at mol ratio of Ir 0.406, Sn 0.210, Sb 0.384 (desirability d value, 1).