• Industry Promotion Research
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• v.8 no.1
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• pp.83-94
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• 2023

This study explored the effect of corporate field teacher and corporate education satisfaction on apprenticeship education satisfaction and student job competency development focusing on NCS job standards and industry-academia-integrated apprenticeship school project group. As a result of the study, satisfaction with corporate field teachers in the electrical, electronic, and food service sectors was found to have a positive influence on improving students' job competency, while satisfaction with corporate education was important in the management, accounting, office, and information and communication sectors. In the analysis by type of project group, the satisfaction of corporate field teachers in the joint practice type and industry-led type had a strong influence on improving job competency, but in the base school type and single school type, corporate education satisfaction had a greater influence on capacity improvement. Therefore, it is necessary to redefine the competencies of corporate field teachers and to establish and implement an industry-academic integrated apprenticeship school operation plan with the relationship between the type of project group and NCS job standard classification.

• Analytical Science and Technology
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• v.19 no.5
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• pp.369-375
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• 2006

Calibration gas mixtures were prepared using dynamic volumetric method according to ISO 6145-5 and the uncertainty was evaluated. Ten identical capillaries with 0.25 mm in inner diameter and 50 cm in length were applied in this system. Dilution ratio of parent gas was determined by the number of capillaries that passes parent gas and that passes balance gas through. Capillaries were made of Teflon which had good chemical stability against adsorption of gaseous substances. Mechanical valves were introduced in this system in order to minimize the thermal effect of solenoid valves. Concentration of prepared gases were compared with master grade standard gases in cylinders made by RiGAS Co. and calibration of the instrument were completed using comparison method according to ISO 6143. Experimental results showed that the coefficient of variance of diluted oxygen standard gases showed less then 0.2% in most dilution range, that of diluted hydrogen sulfide standard gases showed less then 1.0%. Therefore, it is proven that the standard gases prepared by this system are appropriate to be used as a calibration standards in ambient monitoring, etc.

• Analytical Science and Technology
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• v.19 no.6
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• pp.482-489
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• 2006

Two electrode-based lactate biosensor was prepared by immobilizing lactate oxidase (LOD) obtained from pediococcus species in a poly(vinyl alcohol). Hydrogen peroxide ($H_2O_2$) produced by the reaction of lactate and LOD was detected on the Pt-black that was electrochemically deposited on the Au electrode. Sensors fabricated with Pt-black deposited Au electrode provided a high current of $H_2O_2$ oxidation at a substantially lowered applied potential (+300 mV vs. Ag/AgCl), resulting in reduced interferences from easily oxidizable species such as ascorbic acid, acetaminophen, and uric acid. An outer membrane is formulated by adjusting water uptake of hydrophilic polyurethane (HPU). The sensor performance was evaluated in vitro with both flow-through arrangement and static mode. The sensor showed a linear range from 0.1 mM to about 9.0 mM in 0.05 M phosphate buffer (pH 7.6) containing 0.05 M NaCl. Storing the sensors prepared in this work at $4^{\circ}C$ buffer solution while not in use, they provided same electrochemical performance for more than 25 days.

• Analytical Science and Technology
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• v.20 no.5
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• pp.393-399
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• 2007

In principle, the blood galactose level may be determined conveniently with a strip-type biosensor similar to that for glucose. In this study, we describe the development of a disposable galactose biosensor strip for point-of-care testing. The sensor strip is constructed with screen-printed carbon paste electrode (SPCE) and sample amount (< $100{\mu}L$). The developed strip the galactose level in less than 90 s using bienzymatic system of galactose oxidase (GAO) and horseradish peroxidase (HRP). The effects of pH, mediator (1,1-ferrocenedimethanol) concentration, ratio of enzymes, and applied potential were determined preliminarily with glassy carbon electrodes, and optimized further with the strip-type electrodes. The sensor exhibits linear response in the range of $0{\sim}400{\mu}M$ ($r^2$ = 0.997, S/N = 3). Since a low working potential, in principle, the fabricated disposable galactose biosensor has -100 mV (vs. Ag/AgCl), it is applied for the detection of galactose, interfering responses from common interferents such as ascorbic acid, uric acid and acetaminophen could be minimized. The sensor has been used to determine the total galactose level in standard samples with satisfactory reproducibility (CV = 5 %).

• Analytical Science and Technology
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• v.21 no.4
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• pp.284-295
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• 2008

For plastics samples, a method using combustion ion chromatography was selected as a method for rapid low-cost analysis to test whether hazardous substances are contained or not. Using combustion ion chromatography, a verification test for F, Cl and Br compounds generated a linear calibration curve with a correlation coefficient of $r^2$ = 0.999~1.000 in the calibration range from 0.5 to 4.0 mg/kg. The detection limits were found to be 0.005~0.024 mg/kg and quantitative limits were found to be 0.014~0.073 mg/kg. The recoveries of combustion ion chromatography using certified reference material (CRM) were found to be 95.5~104.9%. Based on these results, a proficiency test was conducted together with several laboratories in and out of the country, to make comparative analysis of the results from each laboratory. As a result, the data supported the use of combustion ion chromatography as an effective analysis method to deal with regulations for halogen-free electronic products and for other hazardous substances in the electronic products.

• Journal of Convergence for Information Technology
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• v.12 no.2
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• pp.1-16
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• 2022

Social network service (SNS) using mobile or web is growing rapidly, and the emergence of various platform services is causing innovative changes in social network service (SNS). This study is to identify the target relation factors of social network users and to empirically study the causal relationship of how much these factors affect user satisfaction through pleasure and self-efficacy. To present an effective and efficient development plan in. In order to empirically verify the research model of this study, a survey was conducted with the general public who had experience using social network services (SNS). Path analysis was performed. As a result, it was possible to verify the correlation of the object relational factors on user satisfaction through pleasure and self-efficacy.First, non-excluded had a significant effect on pleasure, but did not significantly affect self-efficacy. Second, stability attachment did not significantly affect both enjoyment and self-efficacy. Third, social ability did not significantly affect both enjoyment and self-efficacy. Fourth, self-centeredness did not have a significant effect on both enjoyment and self-efficacy. Fifth, pleasure had a significant effect on both self-efficacy and user satisfaction. Sixth, self-efficacy had a significant effect on user satisfaction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.871-879
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• 2008

Recently, as there are a rise in the standard of living and higher concerns of an electromagnetic wave and environment, undergrounding the aerial cables which are supported by large pylons and generally considered as the least attractive feature of an urban area is on an increasing trend to improve aesthetic benefits and electric reliability. This study applied Contingent Valuation Method (CVM) which is expected to become an effective tool to measure indirect benefit to estimate the substantial benefits of undergrounding overhead power line projects in an urban area. The tunneling construction project of the 345kV Shinsungnam electric power cable in Seongnam city was selected and a hypothetical scenario was given to respondents to determine their levels of Willingness to Pay (WTP) for undergrounding overhead power lines. The result from the estimation of the WTP of undergrounding overhead power lines in Seongnam city was calculated as approximately 17.1 billion won. Placing existing overhead lines underground is difficult to justify economically. Most undergrounding costs appear to be justified by aesthetic and public policy considerations. Therefore, considering the result of this study, undergrounding overhead power lines is of great benefit to public.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1C
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• pp.11-20
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• 2009

A new alternative method based on HWAW method to detect underground anomaly was introduced. The location of underground anomaly can be estimated by using 2-dimensional image of phase velocity image with position and wavelength based on distortion phenomena of surface wave due to underground anomaly. Overall procedure of proposed method such as field testing, signal processing and interpretation of the result was introduced. Numerical verification study was performed by using various ground models containing underground anomaly. According to the condition of anomaly, the propagation and reflection characteristics of surface wave were different and this could be more easily shown in the image of phase velocity. Some rules of distortion phenomena were found and these become clues for estimating underground anomaly in interpreting real field data. Field verification tests were performed with conventional geophysical methods such as DC resistivity method and GPR. Though field condition is not homogeneous like numerical models, similar distortion phenomena were found in the testing results and estimated location of underground anomaly was agreed well with the results of another geophysical methods.

• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.10-19
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• 2023

This study aimed to examine the early life history of Trident goby (Tridentiger brevispinis) by observing their egg development and juvenile fish morphology. The average size of mature eggs was 1.13~1.41 (1.30±0.07) mm (n=30), and 0.70~0.86 (0.79±0.04) mm (n=30) in long diameter and short diameter, respectively. The incubation period at 24±1℃ ranged from 167~228 h. The newly hatched larvae measured 2.31~2.78 (2.51±0.18) mm (n=30) in total length (TL), and their mouth and anus were not yet open. At 3 days after hatching, the preflexion larvae reached 2.84~3.10 (2.98±0.10) mm in TL, where in their yolk absorption was complete and their mouths began to open. At 19 days after hatching, the larvae reached the flexion stage, measuring 4.02~4.62 (4.36±0.19) mm in TL. The tip of their notochord was bent upward. At 30 days post-hatching, the larvae reached the postflexion stage, measuring between 5.04~6.36 (5.76±0.51) mm in TL, with the tip of the caudal fin bent at 45°. After 54 days, the larvae had reached the juvenile stage, measuring between 7.43~9.84 (8.48±0.90) mm in TL, and were differentiated by their constant number of fins (6 first dorsal, 12 second dorsal, 11 anal, and 10 ventral fins). This study found that T. brevispinis had larger fertilized eggs and a greater number of myotomes in hatching larva than similar species. Additionally, the distribution of melanophores in T. brevispinis was distinct from that in other similar species, making it easy to distinguish them morphologically.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2C
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• pp.99-108
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• 2006

In this study a series of bench scale test are conducted to increase the undrained shear strength of clayey soils using by Electro-kinetic injection stabilization method. The sodium silicate was injected in anode reservoir and its concentration was changed with 500, 1000, 1500, 2000, 2500mM for configuration of applicability of Electro-kinetic injection stabilization method. Also, the treatment time and electric gradient was changed to acquire the optical influence factors. For increasing the shear strength to maximum values, the calcium chloride and aluminium hydroxide, which concentration was changed with 50, 250, 500, 750, 1000mM, were added at anode reservoir for 5 days after the treatment of sodium silicate in 5 days as the 2nd additives. The test of results in determination of sodium silicate concentration show that the undrained shear strength at each point had a tendency to converge into a constant value when the concentration of sodium silicate came to 1000mM and above. The maximum shear strength increasement was 800% compared with initial value. After a series of test, the electric gradient and treatment time for application of electric fielld were 1V/cm and 6 days. In case of 2nd additives test, the concentration for maximum shear strength is 250mM in all additives and the effects of shear strength improvement was developed approximately 20~30% in comparison to addition of single injection material.