• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.154-162
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• 2017

The aim of study was to identify the reliability and validity of an evaluation tool developed on the basis of performance outcome in Women's Health Nursing simulation practicum. A total of 110 undergraduate nursing students were recruited from one college. Data collection of this study was conducted between August and December of 2014. The data were analyzed using factor analysis, multitrait/multi-item matrix analysis, Pearson's correlation coefficient, and Cronbach's alpha with SPSS win 20.0 program. An exploratory factor analysis demonstrated that the four-factor structures of 10 items explained 68.2% of the total variance. It was significantly correlated with the Critical Thinking Disposition scale(r=.42, p <.001). The Cronbach's alpha was 0.89,ranging from 0.61 to 0.92. The results of this study support the reliability and validity of this evaluation tool. It could be a useful tool in evaluating the performance outcome in simulation practicum for nursing students.

• Korean Journal of Remote Sensing
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• v.18 no.4
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• pp.209-220
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• 2002

We carried out studies on SAR image intensity and interferometric phase over oyster sea farms. Strong backscattering was observed in amplitude images, and that was considered as a radar signal double bouncing from horizontal bars. These sea farming structures are not visible in satellite optical images except IKONOS image, so that it demonstrates the value of radar remote sensing as an effective tool in support of sea farm detection. The intensity of the image is sensitive to system parameters including wavelength, polarization, and look direction, but does not correlate to tide height. We found that the strongest backscattering can be obtained by L-band HH-polarization with a look direction perpendicular to the horizontal bar. We also succeeded in generating 21 coherent JERS-1 SAR interferometric pairs over the oyster farms. The general trend of the fringe rate of the interferometric phases appeared to be governed by altitude of ambiguity. The general trend was modeled by an inverse function and removed to have a residual phase. The residual phase showed a linear relation with the tide height. The results demonstrate for the first time that SAR can possibly be used to estimate sea level. However, the r.m.s. error of a regression line is 11.7 cm, and that is so far too large to make reliable assessments of sea level in practical applications. Further studies is required to improve the accuracy specifically using multi-polarization SAR data.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.1-8
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• 2019

Steel elevator pit was developed for the purpose of minimizing the excavation, simplifying the construction of the frame and economical efficiency by improving the problems that occurred in the existing reinforced concrete. It is common to apply conventional RC method through excavation to underground structures such as underground floor collector well and elevator pit. In recent years, the use of steel collector well and steel elevator pits to reduce construction costs by minimizing the materials of steel and concrete has been continuously increasing. The steel elevator pit is an underground structure and then the performance of the welding part and the structure system is important. Specimen with only steel plate and concrete without studs could support the load more than 3 times than the specimen with deck only. Therefore, even if there is no stud, the deck (steel plate) rib is formed and the effect of restraining the steel plate and the concrete during the bending action can be expected. However, since sudden fracture in the elevator pit may occur, stud bolt arrangement is necessary for the composite effect of steel plate and concrete. It is expected that the bending strength can be expected to increase by about 15% or more depending with and without stud bolts.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.3
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• pp.363-375
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• 2019

Since the double-deck tunnel is deeply constructed in the city, it is necessary to secure the installation space of air supply and exhaust, escape passage stairs, elevator, distribution facilities and connection tunnels in the vertical shaft for the double-deck tunnel. Also, in order to minimize the effect of construction on adjacent area, it is necessary to construct the concrete structures at high speed in vertical shaft after tunnel excavation. Therefore, the slabs and the stairs in vertical shaft are needed to be constructed using precast concrete, and the rapid construction techniques of bracket for supporting the inner precast structure are needed. The bracket installation methods include cast-in-place concrete, precast concrete and steel. In this study, the improvement of the steel brackets with good economical efficiency and good workability was carried out in consideration of the improvement of the construction speed. We have developed a new bracket that is optimized through bracket shape improvement, anchor bolt position adjustment and quantity optimization. As a result of the structural performance test, it was confirmed that the required load supporting capacity was secured. As a result of structural performance test for bar type anchor bolt and bent anchor anchor bolt, it was confirmed that the required load carrying capacity was secured and that the load bearing capacity of bent anchor bolt was large.

• Tissue Engineering and Regenerative Medicine
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• v.15 no.6
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• pp.735-750
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• 2018

BACKGROUND: The major challenge of tissue engineering is to develop constructions with suitable properties which would mimic the natural extracellular matrix to induce the proliferation and differentiation of cells. Poly(${\varepsilon}$-caprolactone)-poly(ethylene glycol)-poly(${\varepsilon}$-caprolactone) (PCL-PEG-PCL, PCEC), chitosan (CS), nano-silica ($n-SiO_2$) and nano-hydroxyapatite (n-HA) are biomaterials successfully applied for the preparation of 3D structures appropriate for tissue engineering. METHODS: We evaluated the effect of n-HA and $n-SiO_2$ incorporated PCEC-CS nanofibers on physical properties and osteogenic differentiation of human dental pulp stem cells (hDPSCs). Fourier transform infrared spectroscopy, field emission scanning electron microscope, transmission electron microscope, thermogravimetric analysis, contact angle and mechanical test were applied to evaluate the physicochemical properties of nanofibers. Cell adhesion and proliferation of hDPSCs and their osteoblastic differentiation on nanofibers were assessed using MTT assay, DAPI staining, alizarin red S staining, and QRT-PCR assay. RESULTS: All the samples demonstrated bead-less morphologies with an average diameter in the range of 190-260 nm. The mechanical test studies showed that scaffolds incorporated with n-HA had a higher tensile strength than ones incorporated with $n-SiO_2$. While the hydrophilicity of $n-SiO_2$ incorporated PCEC-CS nanofibers was higher than that of samples enriched with n-HA. Cell adhesion and proliferation studies showed that n-HA incorporated nanofibers were slightly superior to $n-SiO_2$ incorporated ones. Alizarin red S staining and QRT-PCR analysis confirmed the osteogenic differentiation of hDPSCs on PCEC-CS nanofibers incorporated with n-HA and $n-SiO_2$. CONCLUSION: Compared to other groups, PCEC-CS nanofibers incorporated with 15 wt% n-HA were able to support more cell adhesion and differentiation, thus are better candidates for bone tissue engineering applications.

• Design & Manufacturing
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• v.15 no.2
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• pp.11-16
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• 2021

Recently, three-dimensional (3D) cell culture systems, which are superior to conventional two-dimensional (2D) vascular systems that mimic the in vivo environment, are being actively studied to reproduce drug responses and cell differentiation in organisms. Conventional two-dimensional cell culture methods (scaffold-based and non-scaffold-based) have a limited cell growth rate because the culture cannot supply the culture medium as consistently as microvessels. To solve this problem, we would like to propose a 3D culture system with an environment similar to living cells by continuously supplying the culture medium to the bottom of the 3D cell support. The 3D culture system is a structure in which microvascular structures are combined under a scaffold (agar, collagen, etc.) where cells can settle and grow. First, we have manufactured molds for the formation of four types of microvessel-mimicking chips: width / height ①100 ㎛ / 100 ㎛, ②100 ㎛ / 50 ㎛, ③ 150 ㎛ / 100 ㎛, and ④ 200 ㎛ / 100 ㎛. By injection molding, four types of microfluidic chips were made with GPPS (general purpose polystyrene), and a 100㎛-thick PDMS (polydimethylsiloxane) film was attached to the top of each microfluidic chip. As a result of observing the flow of the culture medium in the microchannel, it was confirmed that when the aspect ratio (height/width) of the microchannel is 1.5 or more, the fluid flows from the inlet to the outlet without a backflow phenomenon. In addition, the culture efficiency experiments of colorectal cancer cells (SW490) were performed in a 3D culture system in which PDMS films with different pore diameters (1/25/45 ㎛) were combined on a microfluidic chip. As a result, it was found that the cell growth rate increased up to 1.3 times and the cell death rate decreased by 71% as a result of the 3D culture system having a hole membrane with a diameter of 10 ㎛ or more compared to the conventional commercial. Based on the results of this study, it is possible to expand and build various 3D cell culture systems that can maximize cell culture efficiency by cell type by adjusting the shape of the microchannel, the size of the film hole, and the flow rate of the inlet.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.202-210
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• 2022

Recently with the advance in digital dentistry, the fabrication of dentures using computer-aided design and computer-aided manufacturing (CAD-CAM) is on the rise. The denture designed through a CAD software can be produced in a 3-dimensional manufacturing process. This process includes a subtractive processing method such as milling and an additive processing method such as 3D printing and in which it can be applied efficiently in more complex structures. In this case, complete dentures were fabricated using Stereolithography (SLA)-based 3D printing to shorten the production time and interval of visits in patient with physical disabilities due to cerebral infarction. For definitive impression, the existing interim denture was digitally replicated and used as an individual tray. The definitive impression obtained with polyvinyl siloxane impression material was including information about the inclination and length of the maxillary anterior teeth, vertical dimension, and centric relation. In addition, facial scan data with interim denture was obtained so that it can be used as a reference in determination of the occlusal plane and in arrangement of artificial teeth during laboratory work. Artificial teeth were arranged through a CAD program, and a gingival festooning was performed. The definitive dentures were printed by SLA-based 3D printer using a FDA-approved liquid photocurable resin. The denture showed adequate retention, support, and stability, and results were satisfied functionally and aesthetically.

• Journal of Food Hygiene and Safety
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• v.37 no.5
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• pp.364-371
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• 2022

The bones of the human body support the structures of the body and provide protection for a person's internal organs. Bone metabolic diseases are on the rise due to a significant increase in life expectancy over a short period of time. Therefore, we investigated the osteoblast differentiation promoting and osteoclastogenesis inhibitory activities of fermented Benincasa hispida cong. (HR1901-BS, HR1901-BSaf). We evaluated the alkaline phosphatase (ALP) activity of MC3T3-E1 mouse calvarial-derived osteoblasts. We also evaluated expression of ALP, osteocalcin (OCN), and runt-related transcription factor 2 (Runx2), which regulate osteoblast differentiation. To assess effects on osteoclast formation, tartrate-resistant acid phosphatase (TRAP) activity in RAW264.7 cells was analyzed. ALP activity increased by 121-136% and 140-156%, respectively in the presence of HR1901-BS and HR1901-BSaf. Expression of osteoblast differentiation factor also increased significantly. We also confirmed that HR1901-BS and HR1901-BSaf decreased TRAP activity in osteoclasts by 35-47% and 23-39%, respectively. Our results showed that fermented Benincasa hispida cong. (HR1901-BS, HR1901-BSaf) increase bone mineralization and osteoblast differentiation activity in MC3T3-E1 cells, and inhibit bone resorption activity in RAW264.7 cells. In conclusion, fermented Benincasa hispida cong. (HR1901-BS, HR1901-BSaf) can be used as an effective natural resource for preventing and treating bone-related diseases.

• Journal of Conservation Science
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• v.36 no.6
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• pp.440-455
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• 2020

This study aims to examine the material characteristics of bowls and compare the making techniques of flat cup with cover and jar coffin from the Oryang-dong kiln site, Naju. Bowls, the most frequently excavated small pottery have similar material characteristics, including gray surface, fine-grained texture, and small-sized tempers such as quartz and feldspar, regardless of the excavation slopes. However, the firing temperature of the bowls mostly ranges from 950 to 1,100 ℃. It is estimated that the bowls had formalized making techniques, owing to the similar material composition and firing technique regardless of the excavation slope. The flat cups with cover have similar texture and mineral phases, except their poorly sorted inclusions. However, the jar coffins contain not only fine-grained minerals but also medium-grained quartz, feldspar, and biotite, showing a relatively wide range of firing temperatures. According to the geochemical results of pottery by type, it is assumed that chemical compositions are classified into two groups: small pottery(bowl and falt cup with cover) and jar coffins. In conclusion, small potteries such as bowls and flat cups with cover were made by removing the heavy minerals from raw materials, whereas jar coffins were made by adding medium-grained minerals to raw materials to maintain and support their structures, despite the same source materials. In addition, it is presumed that pottery making proceeded by selecting the source materials, preparing according to their use and controlling the firing temperature and environment.

• Korean small business review
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• v.42 no.2
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• pp.179-193
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• 2020

In the rapid trend of social change, such as the 4th industrial revolution and the realignment of job structures, university-industry cooperation(UIC) is emphasized as a key factor in enhancing national competitiveness. The level of UIC in Korea is insufficient compared to national competitiveness, and despite the world-class R&D investment, there is a lack of linkage between the result of technology development and the industrial field, and the knowledge-transfer between university and industry is also insufficient. This paper analyzed the employment effects of UIC program supported by government, especially youth employment effects. The companies participating in the UIC program showed higher employment effect than the non-participating companies. In addition, the result of examining the employment growth rate of participating companies only for projects aimed at 'education and human resource development', show that employment growth rate after one year (total, youth employment) was significantly higher than that of non-participating companies, while employment growth after two years was not significant. UIC program need to have sustainability and systemicity so that they can be directly linked to the employment effects.