• Coupled systems mechanics
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• v.10 no.2
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• pp.161-184
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• 2021

Strengthening of reinforced concrete beams with externally bonded fiber reinforced polymer plates/sheets technique has become widespread in the last two decades. Although a great deal of research has been conducted on simply supported RC beams, a few studies have been carried out on continuous beams strengthened with FRP composites. This paper presents a simple uniaxial nonlinear analytical model that is able to accurately estimate the load carrying capacity and the behaviour of damaged RC continuous beams flexural strengthened with externally bonded prestressed composite plates on both of the upper and lower fibers, taking into account the thermal load. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, i.e., the damaged concrete beam, the FRP plate and the adhesive layer. The flexural analysis results and analytical predictions for the prestressed composite strengthened damaged RC continuous beams were compared and showed very good agreement in terms of the debonding load, yield load, and ultimate load. The use of composite materials increased the ultimate load capacity compared with the non strengthened beams. The major objective of the current model is to help engineers' model FRP strengthened RC continuous beams in a simple manner. Finally, this research is helpful for the understanding on mechanical behaviour of the interface and design of the FRP-damaged RC hybrid structures.

• Advances in concrete construction
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• v.13 no.6
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• pp.471-479
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• 2022

In this paper, vibrational attributes of double-walled carbon nanotubes (CNTs) has been studied based upon nonlocal elastic shell theory. The implication of small scale is being perceived by establishing nonlocal Love shell model. The wave propagation approach has been operated to frame the governing equations as eigen value system. The comparison of local and nonlocal model has been overtly explored by means of scaling parameter. An appropriate selection of material properties and nonlocal parameter has been considered. The influence of changing mechanical parameter Young's modulus has been studied in detail. The dominance of end condition via nonlocal parameter is explained graphically. The results generated furnish the evidence regarding applicability of nonlocal shell model and also verified by earlier published literature.

• Journal of Korea Trade
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• v.27 no.2
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• pp.61-76
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• 2023

Purpose - The digital service trade has become an important driver of the global service trade. The main purpose of this study is to explore the influencing factors of digital service exports from China and Korea to RCEP sample countries respectively, and to comprehensively study the export potential of China and Korea to RCEP countries, so as to provide theoretical guidance and a decision-making reference to promote digital service trade exports and digital economy development in China and Korea. Design/methodology - First, the stochastic frontier gravity model was improved by introducing nonefficiency factors affecting digital services trade, extending the gravity model of traditional services trade exports to digital services trade exports. Secondly, the panel data of China and Korea for the eight sample countries of RCEP from 2011 to 2021 were adopted for the empirical analysis of digital service export potential by a stochastic frontier model. Findings - China's economic growth plays a role in increasing China's digital service trade exports, while Korea's economic growth does not play a significant role in increasing Korea's digital service trade exports. However, the economic growth of trading partner countries can play a significant role in boosting the digital service trade in both China and Korea, and comparison shows that Korea has higher resilience in the digital services trade than China. In addition, the market size of target countries plays a positive role in promoting the digital service trade exports of both China and Korea, and the increase in the value-added share of services in target countries will lead to a decrease in the digital service trade exports of both China and Korea. Originality/value - This study is innovative in terms of research perspective and method. Academic research on the export potential of international trade has been extensive, but most studies are based on the perspective of the goods trade, fewer studies are based on the perspective of the service trade, and there are almost no studies based on the perspective of digital service trade. There is a gap based on the comparative analysis of the export potential of the digital service trade between China and Korea. This study extends the gravitational model of traditional service trade exports to digital service trade exports to comparatively analyze the export potential of China and Korea to RCEP countries. This study addresses this limitation by analyzing a comparative analysis of the digital service trade export potential of China and Korea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.370-379
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• 2018

The Korean government announced plans for the International Science Business Belt as a spatial area for promoting the linkage between scientific knowledge and commercialization in 2009. R&D and entrepreneurial activities are essential for the success of the International Science Business Belt. In particular, prioritizing the types of businesses is critical at the cluster establishment stage in that this largely affects the features and development of clusters comprising the International Science Business Belt. This research aims to predict the entry and growth of firms that specialize in four industrial clusters, including Big Science Cluster, Frontier Cluster, ICT Cluster, and Bio-Healthcare Cluster. For this purpose, we employ the Swann & Prevezer's industrial clustering model to identify sectors that affect the establishment and growth of industrial clusters in the International Science Business Belt, focusing on ICT, Bio-Healthcare and Frontier clusters. Data was collected from the 2014 Korean Innovation Survey (KIS) and University Alimi for the ICT cluster, 2014 National Bio Industry Survey and University Alimi for the Bio-Healthcare Cluster, and the 2015 National Nano Convergent Industry Survey and Annual Report of Nano Technology for the Frontier cluster. Empirical results show that the ICT service sector, bio process/equipment sector, and Nano electronic sector promote clustering in other sectors. Based on the analysis results, we discuss several policy implications and strategies that can attract relevant firms for the development of industrial clusters.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1559-1569
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• 2014

The purpose of this study is to estimate the degree of cost inefficiency for the urban railway lines of a metropolitan city operated by public institutions in Korea and identify the causes of this inefficiency. To this end, we assume that the urban railway lines produce the output of train-km by putting three production factors of labor, electric power and maintenance and set the variable cost function model with the translog function to make a stochastic cost frontier analysis. Based on estimated result, we conclude that the cost savings for 6 years of all lines are about 6,672 hundred million won and top five lines with high inefficiency are Busan Line1, Daegu Line1, Daejeon Line1, Gwangju Line1, and Daegu Line2. The causes of inefficiency are attributable to labor and maintenance factors. The results of this study can be useful in case of finding the priorities of measures and specific plans for reducing labor and maintenance costs in the urban railway operation.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.1
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• pp.37-43
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• 2014

In current seismic design code, steel moment frames are classified into ordinary, intermediate, and special moment frames. In the case of special moment frames which have large R-factor, economic design is possible by reducing the design lateral force. However, there is difficulty for practical application due to constraints such as strong column-weak beam requirement. This study evaluated if steel intermediate moment frame could maintain enough seismic capacity when the R-factor is increased from 4.5 to 6. As for the analytical models, steel moment frames of 3 and 5 stories were categorized into four performance groups according to seismic design category. Seismic performances of the frames were evaluated through the procedure based on FEMA P695. FEMA P695 utilizes nonlinear static analysis(pushover analysis) and nonlinear dynamic analysis(incremental dynamic analysis, IDA). In order to reflect the characteristics of Korean steel moment frames on the analytical model, the beam-column connection was modeled as weak panel zone where the collapse of panel zone was indirectly considered by checking its ultimate rotational angle after an analysis is done. The analysis result showed that the performance criteria required by FEMA P695 was satisfied when R-factor increased in all the soil conditions except $S_E$.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.6 s.113
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• pp.22-39
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• 2006

This paper is the study on the activity of citizen participation in the movement of Million Amenity Park's creation which was proposed by citizen participation for large scale's flat park within city. This park was proposed by the Busan Green Plan, commission study in 1999. The location of Park site was finally proposed at Dunchi-do, Bonglim-dong, Gangseo-gu, Busan and neighbor areas. The area of park site is approximately 500ha included the surface area of West-Nakdong River. Citizen's organization for Million Amenity Park which has 3,500 members, was established in 2001 in order to compose Million Amenity Park The development processes of this study were found to have quickening period, germination period, the 1st growing period, and the 2nd growing period, and then the results of this activity was also arranged by the researcher of this study. The movement for this park was found to have a positive activity for participating and understanding all the citizens during 7 years. And then the activities for this park were as follows: every information, fund-raising campaign, organization, purchase of park site, contribution of purchasing park site to Busan city. The results of this study, through the movement of citizen's participation such as this park movement were 1) respectively found to have the settlement in the movement of NGO, 2) the possibility of large scale's park fostering by public and civil partnership, and 3) the model presentation of frontier park in the citizen participation's types which will be able to introduce the development of city.

• Particle and aerosol research
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• v.10 no.1
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• pp.1-8
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• 2014

In this study, we have developed a real-time monitoring device for measuring $PM_{10/2.5/1}$ of ambient aerosol particles. The real-time PM (Particulate Matter) monitor was based on the light scattering method and had 16 channels in particle size. The laboratory and field tests were carried out to evaluate the performance of the PM monitor developed. Arizona Road Dust particles ranging from diameter of 0.1 to $20{\mu}m$ were generated as test particles in the laboratory test. The field test was carried out at the Seoul Meteorological Observatory. We can obtain the particle size and number concentration (particle size distribution) only from the real-time PM monitor developed. Therefore, the average density of aerosol particles was used to obtain the PM data from the particle size distribution. The $PM_{10/2.5/1}$ results of the PM monitor were compared with the data of the Grimm Dust Monitor (Model 1.108) and a beta ray gauge (Thermo Fisher Scientific). As a result, it was shown that the $PM_{10/2.5/1}$ results obtained by the real-time PM monitor agreed well with the data of the reference devices, and overall, the real-time PM monitor could be used as a PM monitoring device for real-time monitoring of the ambient particles.

• Journal of Korea Multimedia Society
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• v.25 no.2
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• pp.311-324
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• 2022

In this paper, we adjusted the feedback and learning materials for each learning based on ARCS motivation which applied DEVS methodology. We designed the ARCS professor-student model that expresses the continuous change in the student's attitude toward the class according to the student's attention, relevance, confidence, and satisfaction. It was applied to computational thinking and data analysis classes Based on the designed model. Before and after class, the students were asked the same question and then analyzed for each part of the ARCS. It was observed that students' perceptions of Attention, Relevance, and Satisfaction were improved except for Confidence. we observed that the students themselves felt that they lacked a lot of confidence compared to other ARS through the analysis. Although, Confidence showed a 13.5% improvement after class but it was about 33% lower than the average of other ARS. However, when it was observed that students' self-confidence was 30% lower than other motivational factors it was confirmed that the part that leads C to a similar level in other ARS is necessary.

• Advances in materials Research
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• v.12 no.1
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• pp.43-65
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• 2023

Free vibration analysis of power law and sigmoidal sandwich plates made up of functionally graded materials (FGMs) has been carried out using finite element based higher-order zigzag theory. The present model satisfies all-important conditions such as transverse shear stress-free conditions at the plate's top and bottom surface along with continuity condition for transverse stresses at the interface. A Nine-noded C0 finite element having eleven degrees of freedom per node is used during the study. The present model is free from the requirement of any penalty function or post-processing technique and hence is computationally efficient. The present model's effectiveness is demonstrated by comparing the present results with available results in the literature. Several new results have been proposed in the present work, which will serve as a benchmark for future works. It has been observed that the material variation law, power-law exponent, skew angle, and boundary condition of the plate widely determines the free vibration behavior of sandwich functionally graded (FG) plate.