• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.840-846
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• 2011

In this paper, reflection and RCS characteristic of the EGS(Electromagnetic Gradient Surface) due to incident angle and polarization is analyzed. Incident angle, ${\theta}_i$, is rotated from $0^{\circ}$ to $50^{\circ}$ with $10^{\circ}$ steps and perpendicular and parallel polarization of incident wave are also considered each incident angle. Reflection and RCS characteristic is not much affected by variation of polarization for normal incidence(${\theta}_i=0^{\circ}$). Reflection pattern has different characteristic due to variation of incident angle and polarization but the EGS has about 2 dB of RCS difference due to polarization in RCS characteristic.

• Current Research on Agriculture and Life Sciences
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• v.10
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• pp.35-40
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• 1992

The purpose of this study is to develop regression equations between peak flow and physical characteristic factors of watersheds. 112 irrigation reservoirs located in South Korea which are equal or larger than 200 has. in the irrigation area, are used in the analysis of this study. The results obtained from this study are as follows. 1. The results of correlation analysis of the relationships among the characteristic factors of the watersheds have been derived high significances. 2. Relationship between the peak flow and the simple correlation analysis of physical characteristic factors of the watersheds has been derived low significance. 3. The result of the multiple regression analysis between the peak flow and four physical characteristic factors of watershed such as watershed area, main stream length, average slope of main stream and elevation of reservoir are shown as the equation ; $Q_{100}=66.43A^{0.869}L^{-0.536}S^{0.456}Hs^{-0.122}$.(r=0.838)

• The Journal of Advanced Prosthodontics
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• v.13 no.5
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• pp.269-280
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• 2021

PURPOSE. The objective of this study was to evaluate the effect of thickness reduction and fatigue on the failure load of monolithic zirconia crowns. MATERIALS AND METHODS. 140 CAD-CAM fabricated crowns (3Y-TZP, inCorisTZI, Dentsply-Sirona) with different ceramic thicknesses (2.0, 1.5, 1.0, 0.8, 0.5 mm, respectively, named G2, G1.5, G1, G0.8, and G0.5) were investigated. Dies of a mandibular first molar were made of composite resin. The zirconia crowns were luted with a resin composite cement (RelyX Unicem 2 Automix, 3M ESPE). Half of the specimens (n = 14 per group) were mouth-motion-fatigued (1.2 million cycles, 1.6 Hz, 200 N/ 5 - 55℃, groups named G2-F, G1.5-F, G1-F, G0.8-F, and G0.5-F). Single-load to failure was performed using a universal testing-machine. Fracture modes were analyzed. Data were statistically analyzed using a Weibull 2-parameter distribution (90% CI) to determine the characteristic strength and Weibull modulus differences among the groups. RESULTS. Three crowns (21%) of G0.8 and five crowns (36%) of G0.5 showed cracks after fatigue. Characteristic strength was the highest for G2, followed by G1.5. Intermediate values were observed for G1 and G1-F, followed by significantly lower values for G0.8, G0.8-F, and G0.5, and the lowest for G0.5-F. Weibull modulus was the lowest for G0.8, intermediate for G0.8-F and G0.5, and significantly higher for the remaining groups. Fatigue only affected G0.5-F. CONCLUSION. Reduced crown thickness lead to reduced characteristic strength, even under failure loads that exceed physiological chewing forces. Fatigue significantly reduced the failure load of 0.5 mm monolithic 3Y-TZP crowns.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.107-114
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• 2009

Human walking is essential and important mean of transportation. Pedestrian safety is recently important because accidents often happen while walking. This research is showing that Walking-environmental factors have effect on safety while walking. At first, exact 15 factors and conduct survey in the preceding research. After that, exact 4 important factors through factor analysis. At result of Multiple regression analysis, null hypothesis has proved to be true by satisfying therms which is F-value 9.211 and P-value 0.000. and come to the conclusion that walking-environmental factors influence pedestrian safety. 4 important factors can be listed by below. Pedestrian-road characteristic, landscape characteristic, commercial characteristic, walking characteristics by following influence. Especially, landscape characteristic and pedestrian-road characteristic can be vital factors.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.450-453
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• 2003

This paper presents the estimation on Load Characteristic Factor(k) which is considered to load pattern and seasonal characteristic of consumer. We can calculate the loss of distribution networks through the equation composing of Load Factor(LF), Loss Load Factor(LLF) and load characteristic factor(k). This equation is similar to the method of Regulator-General Victoria, Australia. Generally, the conventional method for calculating the distribution losses uses k with a constant value from 0.1 to 0.3. However, the k which is a relationship between LF and LLF can be varied by load pattern and seasonal characteristics. It is necessary to estimate the k according to load characteristics. This paper shows the result for recalculating k using the KEPCO's SOMAS data measured in distribution networks.

• International Journal of Advanced Culture Technology
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• v.12 no.1
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• pp.182-189
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• 2024

Many South Korean universities highly value and place much investment on the development of students' characteristics as their core competency, offering corresponding educational initiatives and programs. The present study specifically evaluated the level of characteristic competency among freshmen at C University, in which characteristic development is at the central to the institution's core competency. The researchers conducted the study to utilize the findings to inform the design of liberal arts courses and extracurricular programs. The study recruited 210 freshmen at C University in Changwon, South Korea. To ensure anonymity of the respondents, an online questionnaire was administered during the data collection period (i.e., between December 5th and 7th, 2022) with a total of 201 faithful responses finally analyzed. The results showed an average characteristic competency level of 4.21 out of 5 among the freshman participants. Notably, the highest score was ranked in the 'righteous domain' (4.27±0.66), whereas the 'behavioral domain' scored the lowest (4.08±0.77). These findings provide valuable insights for the development of educational programs that aim to promote characteristic competency among university students. The implications of the findings are further discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.7
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• pp.549-555
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• 2021

Open hole strength of composite laminates is often used as the design allowable strength for designing composite aircraft structures, particularly those structures subjected to impact loading. Generally, the degradation of strength due to a barely visible impact damage (BVID) is assumed as the strength of 6.0 mm hole diameter in 24.0 mm width specimen. In this study, the residual strength static tests of composite laminates containing circular holes have been performed to investigate the effects of fiber orientation structure on open hole strength. The point stress criterion using a characteristic length is used to predict the open hole strength. The finite element analysis has been used to validate the analytical method. From the test results, it is shown that the characteristic length is related to the percentage of 0°, ±45° and 90° plies of the laminate. And regression analysis has performed to determine the characteristic length and strength of no hole specimens on the arbitrary layup pattern.

• Laser Solutions
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• v.7 no.3
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• pp.47-50
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• 2004

In this research, we investigated the characteristic of $ZnS_{0.24}Se_{0.76}/GaAs$ heterostructure by using photoreflectance sprctroscopy(PR). The oscillations observed above the 1.43 eV range were attributed Franze-Keldysh effect. The interface electric filed of $GaAs/ZnS_{0.24}Se_{0.76}\;is\;2.153{\times}104\;V/cm$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.165-172
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• 2019

Using two or more coaxial lines, if one port is connected in series and the other port is connected in parallel, it can be implemented the wideband transmission line transformer(TLT). Because the wideband TLT utilizes the outer conductor of the coaxial line, it is difficult to predict the characteristics. In this paper, based on the analysis for the transfer characteristic(S21) according to the loss of the each line in ${\lambda}/4$-microstrip line TLT, the operating characteristic of the fabricated wideband 4:1 TLT using two $25{\Omega}$-coaxial lines is investigated. The fabricated wideband TLT shows the notch characteristic in which the transfer signal sharply decreases at ${\lambda}/4$ frequency of the coaxial line and has a value within -0.2dB of the transfer characteristic(S21) in $0.06{\sim}0.2{\lambda}$ frequency range of the coaxial line. This transfer characteristics(S21) can change the operating frequency range slightly and set the optimum transfer characteristic(S21) at the desired frequency by changing the length of the microstrip line.

• Animal Bioscience
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• v.35 no.11
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• pp.1711-1724
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• 2022

Objective: The present study was to evaluate the effects of different rapeseed meal substitution (RSM) and glutamine (Gln) supplementation on growth performance, intestine morphology, and intestinal mucosa barrier of broilers. Methods: Four hundred and twenty Qiandongnan Xiaoxiang Chicken at 1 day of age with similar weight were chosen and were randomly assigned into 7 groups, consisting of 10 replicates per group and 6 broilers per replicate. Three groups were provided with diets separately containing 0%, 10%, and 20% RSM, and the other four groups were fed with diets separately supplemented with 0.5% and 1% Gln based on the inclusion of 10% and 20% RSM. At 21 and 42 days of age, 10 broilers per group were chosen to collect plasma and intestinal samples for further analysis. Results: The results showed that 10% RSM decreased average daily feed intake (ADFI) and average daily weight gain (ADG) of broilers at 21 days of age (p<0.05). Furthermore, both ADFI and ADG of broilers at 21 and 42 days of age were decreased by 20% RSM, while feed conversion ratio (FCR) was increased (p<0.05). Besides, 10% RSM resulted in lower intestinal villus height and the ratio of villus height to crypt depth, deeper crypt depth (p<0.05), combined with the lower mRNA expressions of occludin, claudin-1, and zonula occludens-1 (ZO-1) in broilers at 21 days of age (p<0.05). Similar results were also observed in broilers at 21 and 42 days of age fed with 20% RSM. However, 1% Gln improved the growth performance of broilers fed with 10% and 20% RSM (p<0.05), ameliorated intestine morphology and elevated mRNA expressions of occludin, claudin-1 and ZO-1 (p<0.05). Conclusion: In conclusion, the increasing inclusion of RSM resulted in more serious effects on broilers, however, 1.0% Gln could reverse the negative effects induced by the inclusion of RSM.