• Structural Engineering and Mechanics
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• v.64 no.3
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• pp.339-346
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• 2017

Slabs prevent harmful effects of fire that may occur in any floor. However, it is necessary to protect the slabs from fire. Insulation materials may be appropriate to protect reinforced concrete (RC) slab from elevated temperature. In the present study, a model has been developed in artificial neural network (ANN) to predict the moment capacity ($M_r$) of RC slabs exposed to fire with insulation material. 672 data were obtained for ANN model through author's prepared program. Input layer in model consisted of seven input parameters; such as effective depth (d), ratio of d'/d, thermal conductivity coefficient ($k_{insulation}$), insulation materials thickness ($L_{insulation}$), reinforcement area ($A_{st}$), fire exposure time ($t_{\exp}$), and concrete compressive strength ($f_c$). The predicted $M_r$ by ANN was consistent with the obtained $M_r$ by author. It is proposed to ease computational complexity in determining $M_r$ using ANN. The effects of using insulation material on the moment capacity in RC slabs were also investigated. Insulating material with low thermal conductivity has been found to be more effective for durability to high temperature.

• Journal of Korean Library and Information Science Society
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• v.34 no.2
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• pp.209-231
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• 2003

A literature analysis for the planning and implementation of information system was carried out to establish the oceanographic R&D results, the first in Korea. The study targeted from scientific & technical report and to oceanographic survey data. The focus of the analysis lies in the providing practical information retrieval service for oceanographic R&D results based on the framework of effective Dublin Core metadata. The analyses included information system organization, web information service process, data input-output process, web visualization process, and retrieval for planning and implementation of oceanographic survey data and scientific & technical report.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1893-1895
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• 1997

This paper presents an analysis of the electromagnetic field in the 3D microwave oven using computational method. The model is accounted the real shape, including the formings, input waveguide with the magnetron, tray, and so on. For quantisation of this problem, Galerkin method with the Nedelec's edge basic functions is used. The system of linear algebraic equations is solved by the iteration method. The simulation results were compared with the experimental results.

• Journal of Korea Foundry Society
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• v.25 no.4
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• pp.156-160
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• 2005

There are many factors that influence solidification behavior during continuous casting, e.g. include superheat, casting speed, cooling rate and holding time. However, when melt is stirred by electromagnetic force, there would be some changes in its solidification behavior compared to that of the ordinary casting process. In this study, the billets of A356 alloy with a diameter of 3 inch were fabricated with electromagnetic stirring under various conditions of superheat, casting speed and input voltage of electro magnetic stirring (EMS) device. The microstructure was also investigated under the various casting conditions and electromagnetic input voltages. When increase in input voltage, the microstructure was changed from dendritic to rosette type and finally to spheroidal. With pouring temperature, casting speed and electromagnetic input voltage were $650^{\circ}C$, 100 mm/min and 140 V, respectively, the billet with a diameter of 3 inch, which has a uniform dispersed spheroidal particles in the whole area of billet except for the surface area, was manufactured.

• Journal of Welding and Joining
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• v.24 no.1
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• pp.64-70
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• 2006

570MPa grade weldable steels were gas metal arc welded with various heat inputs and interpass temperatures using flux cored wires. Effects of heat input and interpass temperature on the strength and impact toughness of weld metal were investigated in terms of microstructural change, recovery of alloying elements, and the amount of reheated weld metal. Increase of heat input and interpass temperature resulted in decrease of weld metal strength. This is because of the small amount of acicular ferrite, large columnar size and low recovery of alloying elements such as manganese and silicon. In addition to the microstructural change, weld metal toughness was also influenced by the deposition sequence. It increased with an increase of the amount of reheated weld metal.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.259-266
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• 2021

This study is a study to systematize the R&D activities of social enterprises to derive a logical model of the R&D support policy, and aims to systematize the R&D activities based on the R&D demand survey and R&D activity analysis of social enterprises. R&D activities of social enterprises are at an early stage or are not systematic compared to general enterprises, so the process modeling method is used to group detailed activity elements to standardize and systemize them. As a result of the research, social enterprises are aware of the necessity and importance of R&D activities to secure competitiveness of products and services to increase social value, and because of their lack of R&D experience and capabilities, R&D specialized institutes (R&D planning institutes, government-funded research institutes), Universities, etc.) and are expected to improve R&D capabilities. The performance indicators of social enterprise R&D activities are derived in units of input-process-performance indicators through demand survey, activity analysis, and in-depth interview (FGI), and the logical model of R&D support policy is in the areas related to business strategy and performance.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.329-341
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• 2017

In order to analyze how the entrepreneurship affects the commercialization performance in relation to R&D input factors, technological innovation and technology in the course of technology commercialization process. Korean manufacturing venture companies has been surveyed. The structural equation model showed technology commercialization mechanism driven by entrepreneurship. Innovativeness is one of the most important factors in the success of venture firms. Technology commercialization was dependent on innovation rather than the input of research and development resources. Technological innovation shows mediating effects in the influence of entrepreneurship on commercialization performance, but technology capability has relatively small effect. Commercialization process of new product development and product improvement was different. The government needs to actively support R&D strategies and commercialization infrastructure in order to promote innovation, assist R&D workforce and enhance product commercialization in venture companies.

• Journal of Powder Materials
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• v.29 no.6
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• pp.459-467
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• 2022

Soft magnetic powder materials are used throughout industries such as motors and power converters. When manufacturing Fe-based soft magnetic composites, the size and shape of the soft magnetic powder and the microstructure in the powder are closely related to the magnetic properties. In this study, Fe-Si-Al-P alloy powders were manufactured using various manufacturing process parameter sets, and the process parameters of the vacuum induction melt gas atomization process were set as melt temperature, atomization gas pressure, and gas flow rate. Process variable data that records are converted into 6 types of data for each powder recovery section. Process variable data that recorded minute changes were converted into 6 types of data and used as input variables. As output variables, a total of 6 types were designated by measuring the particle size, flowability, apparent density, and sphericity of the manufactured powders according to the process variable conditions. The sensitivity of the input and output variables was analyzed through the Pearson correlation coefficient, and a total of 6 powder characteristics were analyzed by artificial neural network model. The prediction results were compared with the results through linear regression analysis and response surface methodology, respectively.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2110-2112
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• 1997

The induction motor drive for the spindle of machining center is required to do not only a constant torque operation in low speed region(below base rpm), but also a constant power operation in high speed region(beyond base rpm). Also, control voltage shortage due to high speed operation must be overcome. The vector controlled inverter system with input 3 phase pwm converter is designed for that kind of condition. We experimented the performance of the inverter system with spindle motor made by Hyosung industries co.

• 한국가스학회:학술대회논문집
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• 1998.09a
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• pp.295-300
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• 1998