• Communications for Statistical Applications and Methods
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• v.12 no.3
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• pp.589-601
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• 2005

Student evaluation of university teaching is a common tool for measuring the educational contribution of a professor and improving the quality of classes. There, however, exist external factors in the beyond of control of a instructor, which affect the result of Student's rating to prevent practical use of evaluation for administrative purpose. This paper investigates the factors that spoil the validity and the reliability of student evaluation and proposes a method to control the effect by the statistical analysis of evaluation data of Jeonju University for two years.

• Journal of Magnetics
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• v.9 no.4
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• pp.97-100
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• 2004

In the present work exchange coupling between ultrathin Fe ($8{\AA}$) and Tb ($12{\AA}$) layers separated by Au spacer of varied thickness ($3-20{\AA}$) was studied. Anomalous Hall effect measurements showed weakly damped oscillating dependence of the Hall conductivity as a function of Au spacer thickness. Disagreement of the observed damping with the RKKY model of interlayer exchange coupling was explained by the influence of external magnetic field on the behaviour of exchange coupling oscillations. It was confirmed by Hall-like effect measurements at zero applied magnetic field and also illustrated by corresponding estimations.

• Bulletin of the Korean Chemical Society
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• v.16 no.11
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• pp.1113-1118
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• 1995

The Schlo'gl model with the first order transition for a photochemical reaction is considered to study the dynamic behaviors in the neighborhood of the Gaussian white noise by obtaining the explicit results of the time-dependent variance and time correlation function with the aid of approximate methods based on the stationary properties of the system. Then, we discuss the effect of external noise strength on the stability of the model at steady states in detail.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.41-51
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• 2018

Downwash from helicopter rotor blades and external winds from various maneuvering make an unguided rocket change its trajectory and range. For the prediction of the trajectory and range, it is essential to consider the downwash effect. In this study, an algorithm was developed to calculate 6-Degree-Of-Freedom(6 DOF) forces and moments exerting on the rocket, and total flight trajectory of a 2.75-inch unguided rocket in a helicopter downwash flow field. Using Actuator Disk Model(ADM) analysis result, the algorithm could analyze the entire trajectory in various initial launch condition such as launch angle, launch velocity, and external wind. The algorithm that considered the interference between a fuselage and external winds could predict the trajectory change more precisely than inflow model analysis. Using the developed algorithm, the attitude and trajectory change mechanism by the downwash effect were investigated analyzing the effective angle of attack change and characteristics of pitching stability of the unguided rocket. Also, the trajectory and range changes were analyzed by considering the downwash effect with external winds. As a result, it was concluded that the key factors of the rocket range change were downwash area and magnitude which effect on the rocket, and the secondary factors were the dynamic pressure of the rocket and the interference between a fuselage and external winds. In tailwind case which was much influential on the range characteristics than other wind cases, the range of the rocket rose as increasing the tailwind velocity. However, there was a limit that the range of the rocket did not increase more than the specific tailwind velocity.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.321-326
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• 2000

This study was performed to analyze the variation of inside temperature of greenhouse according to shading methods. We used two shading method of external and internal method. The shading effect of external screen was superior to internal screen. Soil temperature of greenhouse without screen was higher than outside soil temperature, but the value of greenhouse with internal and external screen was lower than outside.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.566-570
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• 1997

The effect of average gamma energy on the external radiation dose has been analyzed. Cloud- and groundshine have been calculated according to the average gamma energy. Monte Carlo integration method was used for the calculation of cloudshine and Romberg quadrature method was adopted for groundshine. The analysis shows that the external gamma exposure is strong]y dependent on the gamma energy and the distribution of radiation sources.

• Explosives and Blasting
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• v.31 no.1
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• pp.49-54
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• 2013

External charges with four different kinds of tamping materials are tested to determine the effect of tamping on the blasting of steel components and concrete blocks. The tamping materials used are tamping cap, urethane foam, sand bag and mud. As a result, the tamping cap, urethane foam, and sand bag show no significant effect of tamping. But the mud tamping shows that the charge amount can be reduced by more than 20% in completely cutting the structural components. In addition, it is found from the test that the standard equation for calculating the proper charge is rather conservative, which means the equation overestimates the necessary charge for the blasting.

• East Asian Journal of Business Economics (EAJBE)
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• v.8 no.1
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• pp.41-55
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• 2020

Purpose - This paper tries to analyze the factors affecting the utilization of electronic trade of small and medium enterprises and examine how these factors affect the performance of small and medium enterprises. In addition, the leading factors affecting the level of e-trade utilization of small businesses were analyzed by dividing them into external environmental factors affecting the external business and internal resources of the companies themselves Research design, data, and methodology - With a sample of 223 small and medium-sized export firms from South Korea, this study investigates the antecedents of the utilization level of e-Trade such as information exchange, innovation orientation, absorptive capacity and trust by hierarchical regression analysis. Results - The results show that innovation orientation was shown to have a positive effect on e-trade utilization and absorptive capacity has a positive effect on e-trade utilization. Also, information exchange with stakeholders has a positive impact on e-trade utilization. Conclusions - Internal and external factors of companies have a positive effect on the utilization of e-trade. It also showed that the increased utilization of electronic trade had a positive effect on trade performance. Thus, the findings provide policy-makers with implications of the importance of activating e-trade, and furthermore, significant implications for exporter performance.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.21 no.2
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• pp.126-141
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• 2008

Objective : This clinical research was conducted to test patients with Atopic Dermatitis by external application with Yeongyuseungmatang in cosmetics. Methods : We gave scores to 33 patients who visited the Dept. of Oriental Medical Opthalmology & Otolaryngology & Dermatology of Semyung Jecheon Oriental Medical Hospital from April 17th, 2008 to June 12th. Seventeen patients were treated with Yeongyuseungmatang(Experimental group) and sixteen patients were treated with Atopico skin care cream(Control group) for 4weeks. We observed change of total IgE, eosinophil count, Skin Temperature, Transepidermal Water Loss(TEWL), Skin Hydration and Skin pH. Also Clinic Index of Atopic Dermatitis(SCORAD Index) and global assesment of efficacy were used to evaluate the effects of Yeongyuseungmatang. Statistical analysis was performed by using frequency analysis and descriptive analysis. Statistical significance was achieved if the probability was less than 5%(p<0.05). Results : 1. After 4 weeks of external application treatment, SCORAD Index in Yeongyuseungmatang was significant statistically decreased compared with control group. 2. After 4 weeks of external application treatment, eosinophil count in Yeongyuseungmatang was significant statistically decreased compared with control group but total IgE was very increased both Yeongyuseungmatang and control group. 3. Statistically, Yeongyuseungmatang and control group didn't showed significant effect on Skin Temperature was measured by Thermometer SM815. 4. Transepidermal Water Loss(TEWL) in Yeongyuseungmatang was significant statistically decreased compared with control group measured by Tewameter TM300. 5. Skin Hydration in Yeongyuseungmatang was significant statistically increased compared with control group measured by Corneometer CM825. 6. Statistically, Yeongyuseungmatang and control group didn't showed significant effect on Skin pH was measured by Skin-pH-Meter PH905. 7. After 4 weeks of external application treatment, Yeongyuseungmatang showed significant effect on global assesment of efficacy. Conclusion : Considering the above results, we can speculate that cosmetics with Yeongyuseungmatang has some therapeutical effects in mitigating the symptoms of atopic dermatitis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.3
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• pp.211-219
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• 2008

A three-dimensional inviscid flow solver has been developed based on unstructured meshes for the investigation of the effect of the external stores on the tail surfaces of a generic fighter aircraft. The numerical method is based on a vertex-centered finite-volume discretization and an implicit point Gauss-Seidel time integration. The calculations were made for a steady flow and the computed results were compared with experimental data to validate the flow solver. An unsteady time-accurate computation of the generic fighter aircraft with external stores at transonic flight conditions showed that the external stores cause unsteady loading on the horizontal tail surface due to the mutual interference between their wake and the horizontal tail surface. It was shown that downward deflection of the trailing edge flap significantly reduces the undesirable interference effect.