• Steel and Composite Structures
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• v.28 no.1
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• pp.73-82
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• 2018

This paper experimentally and analytically elucidates the shear behavior and shear bearing capacity of partially prefabricated steel reinforced concrete (PPSRC) columns and hollow partially prefabricated steel reinforced concrete (HPSRC) columns. Seven specimens including five PPSRC column specimens and two HPSRC column specimens were tested under static monotonic loading. In the test, the influences of shear span aspect ratio and difference of cast-in-place concrete strength on the shear behavior of PPSRC and HPSRC columns were investigated. Based on the test results, the failure pattern, the load-displacement behavior and the shear capacity were focused and analyzed. The test results demonstrated that all the column specimens failed in shear failure mode with high bearing capacity and good deformability. Smaller shear span aspect ratio and higher strength of inner concrete resulted in higher shear bearing capacity, with more ductile and better deformability. Furthermore, calculation formula for predicting the ultimate shear capacity of the PPSRC and HPSRC columns were proposed on the basis of the experimental results.

• Earthquakes and Structures
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• v.16 no.6
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• pp.757-769
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• 2019

The seismic performance of a coupled shear wall system is governed by the shear resistances of its coupling beams. The plate-reinforced composite (PRC) coupling beam is a newly developed form of coupling beam that exhibits high deformation and energy dissipation capacities. In this study, the shear capacity of plate-reinforced composite coupling beams was investigated. The shear strengths of PRC coupling beams with low span-to-depth ratios were calculated using a softened strut-and-tie model. In addition, a shear mechanical model and calculating method were established in combination with a multi-strip model. Furthermore, a simplified formula was proposed to calculate the shear strengths of PRC coupling beams with low span-to-depth ratios. An analytical model was proposed based on the force mechanism of the composite coupling beam and was proven to exhibit adequate accuracy when compared with the available test results. The comparative results indicated that the new shear model exhibited more reasonable assessment accuracy and higher reliability. This method included a definite mechanical model and reasonably reflected the failure mechanisms of PRC coupling beams with low span-to-depth ratios not exceeding 2.5.

• Journal of Ocean Engineering and Technology
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• v.34 no.6
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• pp.481-488
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• 2020

Composite materialsuch as glass-fiber reinforced plastic and carbon-fiber reinforced plastic (CFRP) shows anisotropic property and have been widely used for structural members and outfitings of ships. The structural safety of composite structures has been generally evaluated via finite element analysis. This paper presents a technique for updating the finite element model of anisotropic beams or plates via natural frequencies. The finite element model updates involved a compensation process of anisotropic material properties, such as the elastic and shear moduli of orthotropic structural members. The technique adopted was based on a discrete genetic algorithm, which is an optimization technique. The cost function was adopted to assess the optimization problem, which consisted of the calculated and referenced low-order natural frequencies for the target structure. The optimization process was implemented with MATLAB, which includes the finite element updates and the corresponding natural frequency calculations with MSC/NASTRAN. Material properties of a virtual cantilevered orthotropic beam were estimated to verify the presented method and the results obtained were compared with the reference values. Furthermore, the technique was applied to a cantilevered CFRP beam to successfully estimate the unknown material properties.

• Journal of Korea Multimedia Society
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• v.21 no.9
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• pp.1090-1098
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• 2018

MQTT is a lightweight messaging protocol that can be used for low power IoT devices. The MQTT basically uses single MQTT broker to indirectly share message information between publishers and subscribers. This approach has a weakness in regard to traffic overflow, connection fault, security, etc. In this paper, we propose a distributed MQTT broker architecture that solves the problems in single MQTT broker structure. The distributed MQTT broker architecture is expected to support new application services that cannot be supported by a conventional MQTT architecture. We have designed and implemented a distributed MQTT broker architecture based on the RPL protocol that has been widely used for IoT network. The experiment results show that the proposed MQTT broker architecture represents better publishing/subscribing latency and network stability than the conventional MQTT broker architecture.

• Journal of Korean Society of Rural Planning
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• v.12 no.4 s.33
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• pp.115-123
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• 2006

The direct payment program for rural landscape conservation in practice since 2005. Recently it is the policy or plan of direct payment for rural landscape conservation attracts great interests as they may help rural people who are very disadvantaged. This paper presents the status of the direct payment program for landscape conservation in rural area and proposed improvements to the program as following; 1) to diversify the plant species, 2) to include other rural elements than plants, 3) to enlarge the areas of crop plantation, 4) to simplify and clarify application process. We sampled two pilot programs, one of spring flower crop and the other of autumn flower crop, and questionnaire surveyed visitors, local government officers and farmers in order to find problems and suggest improvements.

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.180-180
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• 2003

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.123-123
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• 2004

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.1
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• pp.170-181
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• 2015

Generally, because individual agricultural product possesses its own distinctive characteristics and shows different characteristics at each stage of the agricultural supply chain, it is necessary to develop a proper enterprise architecture for managing information system. In this paper, we propose an enterprise architecture based on RFID/USN technology that can be used as a reference enterprise architecture for u-IT application in the agriculture sectors, which is called the u-Farm enterprise architecture with taking heterogeneous characteristics of agricultural products into account for. In addition, we also developed the RFID/USN middleware platform as a core infrastructure technology. Fo evaluation of the performance of the proposed u-Farm architecture and the RFID/USN middleware platform, the field-trial evaluation at the apple Agricultural Processing Center (APC) has been executed and the results shows that the proposed architecture and platform perform well in terms of information integration over the whole SCM process from the farming stage to delivering statge to the customers. It is expected that the proposed u-Farm enterprise architecture can be utilized as a standard information architecture, and the RFID/USN middleware platform can be a infrastructure platform for future u-IT based information technology applications and services in the agricultural environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2497-2504
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• 2013

This study aims to analyze the 'Standard Drawings for School Facilities' issued by Seoul Education Committee in 1975 because it is the early example for middle school architecture. The results of this study are summarized as follows 1) In general trend of single-corridor type block plan, there are also changes in floor plan like no-corridor type block plan, $9.9{\times}6.6m$ classroom unit for the better daylight condition, built-in storage for students. 2) As for elevation design, it is characterized as daylight-oriented, functional exterior for without making full use of design elements. 3) Standardized dimensions are used as a rule in the height of story, ceiling, window sill and etc. Transitional characteristics of the early RC school architecture are found in exposed ceiling, incomplete insulation structure and mixed use of wood framed floor of earlier type. 4) Contrast to main school building, gymnasium shows the intend to express the symbolism of school architecture with diverse elevation design elements and the plasticity of building mass. 5) Separated plan of toilet and night-duty building also show the transitional characteristics. As conclusion, though showing the stereotyped school architecture, on the other hand, 'Standard Drawings for School Facilities' (1975) makes it possible to see the way of coping with the demands for school architecture in that time and the transition of school architecture. This is the main value of it as the material for the studies related to the history of educational facilities.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2007.02a
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• pp.139-151
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• 2007

Decision-making in the crisis management happens in dynamic, rapidly changing, and often unpredictable distributed environments. Crisis management Decision Support Systems (DSSs) in E-Government are challenged by the need to use it availably at anytime, from anywhere, and even under any-situation. In this paper the reasons of developing distributed architecture for crisis management Decision Support Systems (DSSs) in E-Government are analyzed. Consequently, a distributed architecture for crisis management Decision Support System (DSS) is proposed in this paper. Finally it is implemented by Web Services. If crisis management Decision Support System (DSS) based on distributed architecture is implemented by Web Service, then it can provide decision support for decision-makers to deal with crisis at anytime, from anywhere, and even under any-situation.