• Coupled systems mechanics
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• 제10권2호
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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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• 제13권6호
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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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• 제27권2호
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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.

• 한국산학기술학회논문지
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• 제19권2호
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• pp.370-379
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• 2018

우리나라는 중이온 가속기 건설을 중심으로 과학지식이 사업화로 연결될 수 있도록 하는 지리적 공간으로서의 국제과학비즈니스벨트에 관한 계획을 2009년에 확정하였다. 과학기반 클러스터의 형성 단계에서 국제과학비즈니스벨트의 각 클러스터의 우선 유치업종의 선택은 클러스터의 성격과 발전에 많은 영향을 미칠 수 있다는 점에서 매우 중요하다. 본 연구는 정부에서 제시한 국제과학비즈니스벨트의 과학기반 혁신클러스터의 조성을 위해 유치해야 할 핵심 업종들을 제시하고자 한다. 산업별로 클러스터 형성과정이 상이할 뿐만 아니라, 산업 내 특정 업종이 클러스터의 성장과정에 미치는 영향력이 다르기 때문에 혁신생태계 조성을 위한 앵커 섹터를 파악하는 것이 매우 중요하다. 국제과학비즈니스벨트 내 4개 클러스터의 형성 및 성장을 위한 기업을 분석하기 위해 본 연구는 Swann & Prevezer의 산업 클러스터링(industrial clustering) 모델을 활용하여 분석하였다. 본 연구에서는 기업 관련 자료의 경우 2014년의 제조업 및 서비스업 대상 한국기업혁신조사(ICT 클러스터), 2014년 국내 바이오산업 실태조사(바이오헬스케어 클러스터), 2015 국내 나노융합산업 실태조사(첨단산업 클러스터)에 관한 최신자료를 이용하였다. ICT, 바이오헬스케어, 나노 등 3개 산업군에 대한 클러스터링 분석을 수행한 결과 각 산업군에는 다른 여러 섹터에 속하는 기업들의 지역 내 진입을 유발하는 중심적 역할을 하는 섹터들이 있는 것으로 나타났는데, ICT 산업의 경우 정보통신서비스 섹터, 바이오헬스케어 산업의 경우 바이오공정/기기 섹터, 나노 산업군의 경우 나노전자 섹터가 각각 중심적 역할을 하는 것으로 분석되었다. 분석 결과를 바탕으로 본 연구는 국제과학비즈니스벨트 클러스터를 육성하기 위한 기업 유치 전략과 정책에 대한 시사점을 제시하였다.

• 대한토목학회논문집
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• 제34권5호
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• pp.1559-1569
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• 2014

본 연구는 우리나라 공공기관이 운영하는 대도시의 도시철도 노선에 대하여 비용 비효율성의 정도를 도출하고, 이러한 비효율성의 발생 원인을 파악하고자 하였다. 이를 위하여 도시철도 노선을 노동, 동력, 유지보수의 세 가지 생산요소를 투입하여 열차-km의 산출물을 생산하는 형태로 상정하고, 확률적 비용변경 접근법을 이용한 초월대수 함수형태의 가변비용함수모형을 설정하였다. 확률적 비용변경 접근법을 적용한 도시철도 노선의 운영비용 비효율성 분석 결과, 노선 전체의 6년간 절감가능 비용은 약 6,672억원으로 추정되었으며, 비효율성이 높은 상위 5개 노선은 부산1호선, 대구1호선, 대전1호선, 광주1호선, 대구2호선으로 파악되었다. 비효율의 발생원인은 노동과 유지보수 요소에 기인하며, 본 연구의 결과를 활용하면, 도시철도 운영에 있어서의 인력 및 유지보수 비용 절감을 위한 대책의 우선순위와 구체적인 방안 모색에 있어 참고가 가능할 것이라 사료된다.

• 한국지진공학회논문집
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• 제18권1호
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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 $S_E$.

• 한국조경학회지
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• 제33권6호
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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.

• 한국입자에어로졸학회지
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• 제10권1호
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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.

• 한국멀티미디어학회논문지
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• 제25권2호
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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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• 제12권1호
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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.