• Wind and Structures
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• v.25 no.2
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• pp.131-156
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• 2017

This paper deals with the dynamic stability of embedded functionally graded (FG)-carbon nanotubes (CNTs)-reinforced micro cylindrical shells. The structure is subjected to harmonic non-uniform temperature distribution and 2D magnetic field. The CNT reinforcement is either uniformly distributed or FG along the thickness direction where the effective properties of nano-composite structure are estimated through Mixture low. The viscoelastic properties of structure are captured based on the Kelvin-Voigt theory. The surrounding viscoelastic medium is considered nonhomogeneous with the spring, orthotropic shear and damper constants. The material properties of cylindrical shell and the viscoelastic medium constants are assumed temperature-dependent. The first order shear deformation theory (FSDT) or Mindlin theory in conjunction with Hamilton's principle is utilized for deriving the motion equations where the size effects are considered based on Eringen's nonlocal theory. Based on differential quadrature (DQ) and Bolotin methods, the dynamic instability region (DIR) of structure is obtained for different boundary conditions. The effects of different parameters such as volume percent and distribution type of CNTs, mode number, viscoelastic medium type, temperature, boundary conditions, magnetic field, nonlocal parameter and structural damping constant are shown on the DIR of system. Numerical results indicate that the FGX distribution of CNTs is better than other considered cases. In addition, considering structural damping of system reduces the resonance frequency.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.367-372
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• 2006

Government is not only the biggest owner in public sector, but also the leader responsible for improving and fostering construction industry. Delivery systems and award methods are enacted as laws via government's strong will for construction innovation. In addition to establishing relationships between government and contractor, delivery systems and award methods affect every aspect of industry. Therefore, the government should keep trying to remove inefficiency and achieve Best Value. This paper analyzes the delivery systems and award methods of advanced countries to extract lessons for Korean industry focusing on leading parties, direction, and change in owner's awareness of their respective innovative movements for construction. The prerequisites for improvement in delivery systems and award methods are suggested as partnership between public and private sectors, consistent innovation, enhancement in efficiency, and reinforcement of owner's capability.

• Composites Research
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• v.25 no.4
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• pp.117-125
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• 2012

Warpage of the film insert molded (FIM) part is caused by an asymmetric residual stress distribution. Asymmetric residual stress and temperature distribution is generated by the retarded heat transfer in the perpendicular direction to the attached film surface. Since warpage was not prevented by controlling injection molding conditions, glass fiber (GF) filled composites were employed as substrates for film insert molding to minimize the warpage. Distribution of short GFs was evaluated by using micro-CT equipment. Proper models for micro mechanics, anisotropic thermal expansion coefficients, and closure approximation should be selected in order to calculate fiber orientation tensor and warpage of the FIM part with the composite substrate. After six kinds of micro mechanics models, three models of the thermal expansion coefficient and five models of the closure approximation had been considered, the Mori-Tanaka model, the Rosen and Hashin model, and the third orthotropic closure approximation were selected in this study. The numerically predicted results on fiber orientation tensor and warpage were in good agreement with experimental results and effects of GF reinforcement on warpage of the FIM composite specimen were identified by the numerical results.

• Korean Security Journal
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• no.37
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• pp.295-323
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• 2013

This study's purpose examine the "Four Social Evils" policy during about seven months and presents new policy and policy directions with a critical eyes. The present Government focus 'The safety of the people' in 2013. But, most of all, "Four Social Evils" selected the top priority project of the government that will be worked on for the next five years. "Four Social Evils" means Sexual Violence, School Violence, Domestic Violence and Unsanitary Food as crimes affecting the daily lives of the people. To date, we were having a number of discussions with various people. But currently, there is a lack of research on constructive criticism about "Four Social Evils" policy. Therefore, It is the best thing to get interested in "Four Social Evils" policy and evaluate the effectiveness at this time. But, This study is not simply criticizing the "Four Social Evils" policy. Ultimately, through this constructive criticism, this study is trying to encourage "Four Social Evils" policy in the right direction and serve as the groundwork for reinforcement strengthen of the social safety net.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.167-177
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• 2019

The enhancement of national competitiveness in future society is the discovery and training of excellent SW convergence gifted. In order to cultivate these SW convergence gifted, reinforcing competence of teachers in charge should be made first. Therefore, in this paper, artificial intelligence education contents, one of the core technologies of the 4th Industrial Revolution era, were developed to reinforcing competence of SW convergence gifted teachers. After setting the direction of artificial intelligence education content, we constructed educational content suitable for secondary SW convergence gifted education, and designed and developed it in detail. The composition of artificial intelligence education content consists of machine learning and tensor flow understanding, linear regression machine learning implementation for numerical prediction, and multiple linear regression-based price prediction machine learning implementations. The developed educational contents were verified by experts with qualitative aspects. In the future, we expect that the educational content of artificial intelligence proposed in this paper will be useful for strengthening the ability of SW convergence gifted teachers.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.49-57
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• 2014

A deterioration of typical reinforced concrete (RC) bridge deck is due to the use of calcium chloride, cracks and water penetration inside of the deck slab with steel reinforcement. In order to eliminate the defects of RC decks in terms of material, therefore, the steel-strapped deck system is studied and developed by maximizing the arching effect while the girders are restrained using straps in lateral direction to the bridge. This parametric study was performed to analyze the structural characteristics of steel-strapped deck, and to identify the factors of the thickness, span length and lateral restraint stiffness of deck slab considering the concrete non-linearity. Finally, a design equation, which is adequate to South Korea, is suggested.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.836-845
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• 2016

The variation and structure of the cold water mass around Ganjeol Point during the summer of 2011 were studied using data from CTD observations and temperature monitoring buoys deployed at 20 stations off the southeast coast of Korea. There was a $-12^{\circ}C$ surface temperature difference between the cold water mass and normal water during the monitoring period. Variations in the isothermal lines for surface temperature along the coast showed that the seabed topography at Ganjeol Point played an important part in the distribution of water temperature. Cold water appeared when the wind components running parallel to the coast had positive values. The upwelling -response for temperature fluctuations was very sensitive to changes in wind direction. Vertical turbulent mixing due to the seabed topography at Ganjeol Point can reinforce the upwelling of cold bottom water. From wavelet analysis, coherent periods found to be 2-8 days during frequent upwelling events and phase differences for a decrease in water temperature with a SSW wind were 12-36 hours.

• The Journal of the Korea Contents Association
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• v.6 no.11
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• pp.317-326
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• 2006

By the rapid progress of U-IT(Ubiquitous Information Technology), a variety of national development policies have been devised on the basis of the utilization of the technology Above all things, a number of local governments are driving to construct a 3D GIS(Geographical Information System) that is as a infrastructure for the regional development which is including a u-City construction as a future city model, the competitiveness reinforcement of local governments, a reasonable means of urban management, etc. In this study we tried to find the fundamental direction of construction and utilization of 3D GIS in local governments. As the result of study, we suggested the advanced vision of 3D GIS has a role of treating the public affairs of local governments and of supporting the various private business scope.

• The Journal of Fisheries Business Administration
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• v.48 no.1
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• pp.31-49
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• 2017

This study focuses on developing a theoretical framework for evaluating Operational Performance of the Marine Forest Creation project on a balanced and comprehensive perspective by using BSC, AHP, and IPA. Also, the purpose of this study is empirically to analyze operational performance of the project and to suggest the future improvement plan. For this purpose, We will first determine the critical success factors(CSF) and key performance indicators(KPI) required for evaluating the performance of the Marine Forest Creation project from the four perspectives of BSC. And, After determining the weight for each of CSF, KPI, and four perspectives of BSC by using AHP, we will measure the project performance. We will also conduct IPA analysis to propose the direction of improvement of the Marine Forest Creation project. The results of this study are as follows. First, this study has drawn 8 critical success factors and 16 key performance indicators for four BSC perspectives based on the theoretical considerations and expert interview survey. Second, as a result of deriving relative importance of BSC perspectives using AHP, customer perspective was the highest, followed by financial perspective, learning and growth perspective, and internal process perspective. Third, as the results of analyzing the importance and performance of BSC perspectives using IPA, customer perspective was the maintenance reinforcement category, financial perspective was the key improvement category, internal process perspective and learning and growth perspective were gradual improvement category. This study has a great academic significance in terms of BSC first tried to evaluate the performance of the Marine Forest Creation project. The results of this study are expected to lead to various discussions for a balanced and comprehensive verification of Marine Forest Creation project performance.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.4
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• pp.171-180
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• 2014

Since the execution of structural design by professional structural engineers is not mandatory for small-size buildings in Korea, structural design is conducted by architects or contractors resulting in concern about the seismic safety of the buildings. Therefore, the Korean Structural Engineers Association proposed dedicated structural design criteria in 2012. The criteria were developed based on a deterministic approach in which the structural members are designed only with information of story and span length of the buildings and without structural analyses. However, due to the short time devoted to their development, these criteria miss satisfactory basis and do not deal with structural walls popularly used in Korea. Accordingly, the Ministry of Land, Infrastructure and Transport launched a research on the 'development of structural performance enhancement technologies for small-size buildings against earthquakes and climate changes'.. As part of this research, this paper intends to establish direction for the preparation of deterministic structural design guidelines for seismic safety of domestic small-size reinforced concrete buildings. To that goal, a typical plan of these buildings is selected considering frames only and frames plus walls, and then design is conducted by changing the number of stories and span length. Next, the seismic performance is analyzed by nonlinear static pushover analysis. The results show that the structural design guidelines should be developed by classifying frames only and frames plus walls. The size and reinforcement of structural elements should be provided in the middle level of the current Korean Building Code and criteria for small buildings by considering story and span length for buildings with frames only, and determined by considering the shape and location of walls and the story and span length as well for buildings with frames plus walls. It is recommended that the design of walls should be conducted by reducing the amount of walls along with symmetrically located walls.