• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.2
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• pp.1-17
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• 2021

As population concentration, high-rise, and high-density progresses amid rapid industrialization and urbanization in Korea, green areas in the city have decreased significantly and the natural environment has deteriorated day by day due to various development projects. In order to cope with these social changes, many studies related to park and green areas have been conducted, but in the case of Gwangju-si, only studies on green areas such as vegetation structures, street facilities, and recreation forests have been conducted on park green areas. The situation is not losing. Therefore, in this study, a survey was conducted on Gwangju citizens to understand the usage behavior and satisfaction of park green areas, and to provide basic data for future park development and reorganization. As a result, first, to induce a variety of static and dynamic activities in order to increase the park satisfaction of Gwangju citizens, it is possible to create a park that has not been formed as soon as possible, and by planning programs with various themes. Second, it is necessary to expand green space services in marginalized areas by creating water streams, flower pots, and rooftop greening around the lives of Gwangju citizens, and create park green spaces with themes using cultural and historical resources for each administrative district. Third, in order to solve the dry landscape in some urban areas, it is necessary to establish a three-dimensional landscape plan by creating a variety of green areas such as potted plants, green areas, and street trees, and by giving functions of park green areas such as expanding leisure and convenience facilities.

• Journal of Information Technology Services
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• v.20 no.5
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• pp.1-9
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• 2021

Since the first confirmed case in January 2020, Coronavirus disease 2019(COVID-19) has brought many changes to our society, and Korea is no exception. Some changes are direct and immediate such as restrictions on overseas travel and social distancing, but the others are indirect and slowly adapted such as lifestyle changes impacting industries and businesses. IT service sector is tremendously influenced by COVID-19. IT service is used extensively in response to COVID-19 taking advantage of its non-face-to-face characteristics. In that sense, the industry is positively affected and in some sense invigorated, giving birth to new kind of services. This special issue focuses on introducing how the IT services are affected, what kind of transformations are undergoing, and how these are expedited after COVID-19. This special issue expands and extends the case research section by collecting new IT service case studies concerning these topics. After competitive review process, 11 studies are selected for this special issue which deals with four different but closely related aspects: (1) evolutions of private IT services, (2) transformations in public IT services, (3) impacts in the hospitality and tourism industry, and (4) changes of people's behavior along with COVID-19. The first set reports on the evolution of private IT services that have created terms such as foodtech and edutech as we enter a rapid non-face-to-face situation. The second set consists of studies dealing with the evolution of public IT services. Evolution and rapid response to non-face-to-face appear to be no exception in the public sector. The third includes studies of hospitality and tourism which is most strongly affected by COVID-19. The last set deals with the behavioral changes of users such as technostress in telecommuting. Lessons learned through best practices and key problems identified in these studies may help us to actively respond to the coming waves of changes incurred by COVID-19 in our society as well as in the IT service industry.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.573-575
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• 2016

Consumption habits of children who economic consumption habits has not been established is a very big concern for parents. According to the credit recovery committee (2006) youth consumption behavior and needs assessment of the education of, he answered that 60.9% of young people have experienced the impulse buying. Student consumption of is done in pin money to receive almost to the parent. Most of the pin money, in order to be paid in cash, is often consumed with the payment directly in the offline sales floor. Pin money is, or waste to students senseless consumption, to trick the price of the purchase goods, to parents, so as to require a greater amount without parental monitoring and agree. In this paper, we would like to propose a system to solve the problem of giving the authority to make decisions off-line payment from student to the parent.

• Journal of Powder Materials
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• v.29 no.3
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• pp.207-212
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• 2022

Nanosized rutile titanium dioxide (TiO₂) is used in inorganic pigments and cosmetics because of its high whiteness and duality. The high quality of the white pigments depends on their surface coating technique via the solgel process. SiO₂ coatings are required to improve the dispersibility, UV-blocking, and whiteness of TiO₂. Tetraethyl orthosilicate (TEOS) is an important coating precursor owing to its ability to control various thicknesses and densities. In addition, we use Na₂SiO₃ (sodium silicate) as a precursor because of its low cost. Compared to TEOS, which controls the pH using a basic catalyst, Na₂SiO₃ controls the pH using an acid catalyst, giving a uniform coating. The coating thickness of TiO₂ is controlled using a surface modifier, cetrimonium bromide, which is used in various applications. The shape and thickness of the nanosized coating layer on TiO₂ are analyzed using transmission electron microscopy, and the SiO₂ nanoparticle behavior in terms of the before-and-after size distribution is measured using a particle size analyzer. The color measurements of the SiO₂ pigment are performed using UV-visible spectroscopy.

• Steel and Composite Structures
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• v.51 no.5
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• pp.509-527
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• 2024

Bonding carbon fiber-reinforced polymer (CFRP) laminates have been extensively employed in the restoration of steel constructions. In addition to the mechanical properties of the CFRP, the bond strength (P_U) between the CFRP and steel is often important in the eventual strengthened performance. Nonetheless, the bond behavior of the CFRP-steel (CS) interface is exceedingly complicated, with multiple failure causes, giving the P_U challenging to forecast, and the CFRP-enhanced steel structure is unsteady. In just this case, appropriate methods were established by hybridized Random Forests (RF) and support vector regression (SVR) approaches on assembled CS single-shear experiment data to foresee the P_U of CS, in which a recently established optimization algorithm named Aquila optimizer (AO) was used to tune the RF and SVR hyperparameters. In summary, the practical novelty of the article lies in its development of a reliable and efficient method for predicting bond strength at the CS interface, which has significant implications for structural rehabilitation, design optimization, risk mitigation, cost savings, and decision support in engineering practice. Moreover, the Fourier Amplitude Sensitivity Test was performed to depict each parameter's impact on the target. The order of parameter importance was t_c> L_c > E_A > t_A > E_c > b_c > f_c > f_A from largest to smallest by 0.9345 > 0.8562 > 0.79354 > 0.7289 > 0.6531 > 0.5718 > 0.4307 > 0.3657. In three training, testing, and all data phases, the superiority of AO - RF with respect to AO - SVR and MARS was obvious. In the training stage, the values of R² and VAF were slightly similar with a tiny superiority of AO - RF compared to AO - SVR with R² equal to 0.9977 and VAF equal to 99.772, but large differences with results of MARS.

• The Journal of the Korea Contents Association
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• v.16 no.10
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• pp.255-266
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• 2016

Oral health knowledge, awareness and attitude towards parents of the dental hygiene students is giving a mutual influence over their children enrolled in the dental hygiene department. Therefore, the university is a situation that requires students to oral health education that can be caused by changes in attitudes and behavior, rather than a simple knowledge transfer. This study was performed to compare the differences in oral health knowledge and awareness of dental hygiene department parents. Research method was used to survey the SPSS v19.0 through the Google study has used a total of 200 in the final analysis to the National Dental Hygiene Department of the lower grades (first grade) and seniors (fourth grade), the student's parent. The results child's impact as a student in the dental hygiene department is older group were more statistically significant than the younger group. Oral Health Knowledge average of the parents of the grade your child is younger parents, older parents, cognitive average younger parents, older parents, education, whether through a child younger parents older parents, the impact is younger parents was higher in the upper grades to both parents of older parents. Therefore, the older the child the more it can be seen that grade their knowledge and habitual behavior affects the oral health knowledge and awareness of their parents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.54-62
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• 2017

This paper describes the behavior and failure probability of the basic structural members in a fire for the fire safety assessment of offshore structures. A fire safety assessment can be accomplished by comparing the fire resistance of the members with the fire severity of the heat load due to fire. The fire severity is represented as the maximum temperature of the members using the Eurocode 1 standard fire curve and heat transfer equation. On the other hand, the fire resistance is the limiting temperature calculated by a simplified formula in the case of simple structural members. Considering the complexity of FPSOs and offshore structures, a general-purpose structural analysis program should be used and the limiting temperature obtained by analyzing the structural strength of the members through an elasto-plastic analysis with a large deflection, and compared with the maximum temperature. Also, the equality of these two methods of evaluating the fire resistance was confirmed by comparing them. Following three criteria, the strength, serviceability and stability, three failure modes, namely the first failure of a hinge, large deflection and buckling, were chosen. The failure temperature was verified for each failure mode. using the AFOSM method in the equation of the fire severity and fire resistance, thereby giving the failure probability of the member. By applying these processes to the example of a beam and plate, the behavior of the structure and failure (temperature?) of each failure mode can be determined.

• Elastomers and Composites
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• v.46 no.1
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• pp.45-53
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• 2011

The effect of the silane coupling agent, bis(triethoxysilypropyl)tetrasulfide (TESPT), on mechanical properties of a silica-filled NBR compound for oilseal was investigated. Curing behavior and crosslinking density of the compounds were measured using ODR (oscillating disk rheometer) and swelling ratio in toluene. UTM (universal testing machine) and shore A hardness tester were used in order to study the characteristics of mechanical properties of original vulcanizates and aged ones with heated air and ASTM No. 3. oil. Recovery of elasticity which influences the performance and service life of oilseal was investigated by giving bending deformation to vulcanizates in aging condition. After bending aging test, recovery distance was measured and calculated angle of recovery from it. TR (temperature retraction) test was performed on these vulcanizates to determine the low temperature recovery behavior. Wear resistance was measured by Taber type abrasion tester. In addition, SEM was used to characterize the morphology of the worn surface of vulcanizates. The result showed that addition of TESPT into silica-filled compound improves not only compound flow-ability, interaction between NBR and silica and crosslinking density, but also hardness, 100% modulus, recovery of elasticity, wear resistance, heat resistance and ASTM No.3 oil resistance of vulcanizates.

• Journal of the Korean Geotechnical Society
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• v.23 no.8
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• pp.159-169
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• 2007

The behavior of fiber-reinforced cemented sands (FRCS) was studied to improve a brittle failure mode observed in cemented sands. Nak-dong River sand was mixed with ordinary Portland cement and a Polyvinyl alcohol (PVA) fiber. A PVA fiber is widely used in concrete and cement reinforcement. It has a good adhesive property to cement and a specific gravity of 1.3. A PVA fiber has a diameter of 0.1 mm that is thicker than general PVA fiber for reinforced cement. Clean Nak-dong River sand, cement and fiber at optimum water content were compacted in 5 layers giving 55 blows per layer. They were cured for 7 days. Cemented sands with a cement/sand ratio of 4% were fiber-reinforced at different locations and tested for unconfined compression tests. The effect of fiber reinforcement form and distribution on strength was investigated. A specimen with evenly distributed fiber showed two times more strength than not-evenly reinforced specimen. The strength of fiber-reinforced cemented sands increases as fiber reinforcement ratio increases. A fully reinforced specimen was 1.5 times stronger than a specimen reinforced at only middle part. FRCS behavior was controlled not only by a dosage of fiber but also by fiber distribution methods or fiber types.

• 한국노년학
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• v.34 no.2
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• pp.215-228
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• 2014

This study aims to develop a scale to measure the elderly's intention on home renovation and to verify its validity. As a methodological study based on the theory of planned behavior, this study provides 26 preliminary items in the pre-test. The first main test, performed to verify the content validity of the developed items, was followed by a second test of construct validity and reliability. As the result of the content validity test targeting experts, some of the original 26 items were excluded, while others were combined for a total of 22. As the result of the construct validity test of the scale, targeting the elderly aged 65 and over, the 22 items were narrowed down to 14 items, excluding the items that were unsuitable for communality and Eigen value. After once more conducting a factor analysis, the items were classified into five factors with a total cumulative variance of 72.5% and a Cronbach's α of 0.75. This study will contribute to the discussion of housing for the elderly by giving force to environmental regeneration activities through facilitating the identification of the home owners' intentions to renovate in order to improve the physical environment in decayed areas at a public level.