• International Journal of Highway Engineering
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• v.20 no.4
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• pp.27-34
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• 2018

PURPOSES : The objective of this study is to evaluate the physical properties of recycled asphalt mixtures reinforced with glass fiber. METHODS : Firstly, mixing design was conducted on recycled asphalt mixture for use of 50% recycled aggregate. Various laboratory tests were performed on four types of recycled asphalt mixtures with different glass fiber content to evaluate the physical properties. The laboratory tests include indirect tensile strength test, dynamic modulus test, Hamburg wheel tracking test and tensile-strength ratio to evaluate cracks, rutting and moisture resistance of mixtures. RESULTS : The indirect tensile strength of fiber reinforced glass increased about 139.4%. As a result of comparing the master curves obtained by the dynamic modulus test, the elasticity was low in the low temperature region and high in the high temperature region when the glass fiber was reinforced. The glass fiber contents of PEGS 0.3%, Micro PPGF 0.1% and Macro PPGF 0.3% showed the highest moisture resistance and rutting resistance. CONCLUSIONS : The test results show that use of glass fiber reinforcement can increase the resistance to cracking, rutting, and moisture damage of asphalt mixtures. It is also necessary to validate the long-term performance of recycled asphalt mixtures with glass fiber using full scale pavement testing and field trial construction.

• Journal of Korea Foundry Society
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• v.37 no.4
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• pp.115-122
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• 2017

The aim of this research is to evaluate the wear properties of (TiB+TiC) paticulate reinforced titanium matrix composites (TMCs) by in-situ synthesis. Different particle sizes (1500, $150{\mu}m$) and contents (0.94, 1.88 and 3.76 mass% for Ti, 1.98 and 3.96 mass% for the Ti6Al4V alloy) of boron carbide were added to pure titanium and to a Ti6Al4V alloy matrix during vacuum induction melting to provide 5, 10 and 20 vol.% (TiB+TiC) particulate reinforcement amounts. The wear behavior of the (TiB+TiC) particulate reinforced TMCs is described in detail with regard to the coefficient of friction, the hardness, and the degree of reinforcement fragmentation during sliding wear. The worn surfaces of each sliding wear condition are shown for the three types of wear studied here: transfer layer wear, particle cohesion wear and the development of abrasive areas. The fine reinforcements of TMCs were easily fragmented from the Ti matrix as compared to coarse reinforcements, and fragmented debris accelerated the decrease in the wear resistance.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.6
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• pp.763-780
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• 2012

The purpose of this study was to develop the teaching & learning model to increase the key competencies in the university. For this, the researcher suggested the draft of teaching & learning model in the university based on literature analysis and survey for key competencies education to professors and students. After that, the draft of the model was revised through the formative test by experts. And then, the revised model was verified through delphi survey and a final model was fixed. As the result of this study, features of the final model are as follows. First, this study identified that a core values of teaching and learning model for the key competencies education in the university is reinforcement of learner's thinking skills and enhancement of field oriented on learning contents and reinforcement of professor's role as a mentor, a facilitator, a motivator, and an informant. Second, The core learning activity's process of the teaching and learning model for the key competencies education in the university consists of the following in order: team-building, exploring problem, gathering and analysing informations, arranging of leaning outcomes, comprehensive arrangement and self-examination.

• Journal of Korean Elementary Science Education
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• v.30 no.1
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• pp.38-50
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• 2011

As the rate of foreign workers increasing, the rates of their children are rising, as well. The children's native countries vary from Japan, China to Indonesia, and difficulty of learning is expected in their entering the regular education due to the differences in the contents and curriculum they had learnt. This study analyzed the science textbooks of five Asian elementary schools including Korea, China, Indonesia, Thailand, and Iran-in diversified sides focusing on the content of earth science, for the children of foreign workers. The characteristics of the elementary science textbooks of the subject countries were compared in seven criteria-the rate of earth science in the textbooks, how units are arranged, whether the earth science contents are included, the contents highly related to their socio-cultural traits, photographs, scientific inquiries, and test items. The textbooks showed numerous differences with their own characteristics, and it is expected that the children of foreign workers would face difficulties in studies taking parts in the Korean formal education. Hereupon, this study proposes the needs of development of sub-materials for the children of foreign workers adapting to schools, and reinforcement of educating teachers for understanding children, with a national plan for the children excluded from education due to problems such as an illegal residence.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.5
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• pp.63-69
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• 2000

The main target of this research is investigating the relations between mechanical properties and injection conditions, like injection pressure, packing pressure and packing time for various contents ratio of glass fiber and resin. In general idea, high injection pressure produces high strength of molded parts as a monotonic function. but it was revealed that high pressure does not make high strength directly through various experiments of injection molding. In this experiments, PA66 was selected as resin and Glass Fiber was selected as reinforcing fiber Fiber reinforcement was controlled, as 14%, 25%, 33%, 44% of total volume and packing pressure was divided 55%, 65%, 75%, 85% of reference pressure, i.e. 100% equal to 1400kgf/$\textrm{cm}^2$. Finally, tensile testing was executed for injected test specimen. Optimum results based on authors' experiments have been obtained under conditions of 25% and 33% of glass fiber contents. Tensile strength rather depends on the packing pressure and packing time than injection pressure. Especially almost equal value of tensile strength was obtained for various percentage of packing and injection pressure as 65%, 75% and 85% of reference pressure.

• Coupled systems mechanics
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• v.11 no.3
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• pp.267-284
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• 2022

Due to the high usage of ABS in industries, such as aerospace, auto, recreational devices, boat, submarines, etc., the purpose of this project was to find a way to weld this material, which gives advantages, such as affordable, high speed, and good connection quality. In this experimental project, the friction welding method was applied with parameters such as numerical control (NC) machine with two different speeds and three cross-sections, including a flat surface, cone, and step. After the end of the welding process, samples were then applied for both tensile and bending tests of materials, and the results showed that, with increasing the machining velocity Considering of samples, the friction of the surface increased and then caused to increase in the surface temperature. Considering mentioned contents, the melting temperature of composite materials increased. This can give a chance to have a better combination of Nanomaterial to base melted materials. Thus, the result showed that, with increasing the weight percentage (wt %) of Nanomaterials contents, and machining velocity, the mechanical behavior of welded area for all three types of samples were just increased. This enhancement is due to the better melting process on the welded area of different Nano contents; also, the results showed that the shape of the welding area could play a significant role, and by changing the shape, the results also changed drastically.A better shape for the welding process was dedicated to the step surface.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.2
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• pp.70-75
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• 2022

With the spread of various digital devices, devices have become commonplace in modern society. Moreover, due to the increase in device usage and online learning while staying indoors during the COVID-19 pandemic, symptoms such as an increase in myopia in children due to eye fatigue, an increase in young presbyopia, and dry eye syndrome are increasing, and now people are paying attention to eye health. This is different from before. There are various prescriptions for eye health, but in this paper, we would like to propose a training method for enhancing visual function using VR contents. The analog methods of the existing teaching aids for visual function reinforcement training were planned and produced as digital contents, and VR-based training contents were selected from among the various methods carried out with teaching aids at the visual function training center, which can be made into contents. was developed with In the training process for each content, it was proposed to apply eye tracking to the VR device in order to give the user feedback on their participation in the training so that the management and concentration of the training process could be analyzed.

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.44-53
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• 2022

The purpose of this study is to plan and develop contents for training social skills using robots for elementary school students. Seven functions (guiding activity, providing reinforcement, guiding students behavior, team setting, presenting team order, timer setting, and checking scores) were developed by analyzing functions that robots can take charge of in the training contents. A total of 8 sessions of social skills training contents were developed by selecting social skills required for academic achievement and social interaction of elementary school students. The lesson consisted of providing positive and negative examples, modeling, role-playing, providing feedback on performance, and encouraging generalization stages using effective strategies for acquiring social skills. After developing social skills training contents using robots for elementary school students, so-called Friendly Friends (FF), a satisfaction survey was conducted on the field application of contents and participating students and teachers to examine the acceptance pattern. As a result, it was found that the participating students and teachers were satisfied with the contents. Finally, the meaning and the expected effects of the 'FF (Friendly Friends)' contents were discussed, and also, the matters to be considered when developing social skills training contents using robots in the future were suggested.

• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.192-209
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• 2011

This study looked into coping strategies of local terrestrial broadcasting companies in the media market, since the introduction of comprehensive programming channels was confirmed. Local terrestrial broadcasting companies vulnerable to market competitiveness are driven more out to the difficulty of survival in a limited advertising market with the advent of comprehensive programming channel. and Local terrestrial broadcasting receive discriminative application than comprehensive programming channel. They have reverse discrimination in must-carry, broadcasting area, programming regulation, advertisement regulation, broadcasting development fund. Hence, Local terrestrial broadcasting needs diverse countermeasures at difficult media circumstances. Above all, Competitive content reinforcement is desperately needed. That's why content distribution structure needs diversification. And, It is necessary for local terrestrial broadcasting companies to diversify the content distribution system. As a way to expand distribution structure of local broadcasting, the introduction of local programming regulations for total amount will be highlighted in the nationwide network program. The mandatory policy that programs produced by local terrestrial broadcasting companies will be broadcast regularly in prime time through a nationwide network is an example. In addition to developing high content independently, 2nd Multiple channels of distribution is needed. It has to be supplied to various platforms including local broadcasting, SO and etc. In addition, it is necessary to activate regional co-production program between local terrestrial broadcasting companies and regions. Time rate between central stations and local terrestrial broadcasting companies must be distributed practically. And also, local terrestrial broadcasting companies in addition to ad revenue model to themselves and their own businesses by expanding the sponsorship to strengthen the competitiveness will have to nurture self-sustaining. Moreover they must have enlarge economy of scale through widen of broadcasting area.

• Journal of Engineering Education Research
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• v.19 no.3
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• pp.13-22
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• 2016

The purpose of this study is to analyze middle and high school technology teachers' recognition and educational need about engineering education. For this, we surveyed secondary school technology teachers. The result of this study is as follow. First, most technology teachers perceive that engineering contents are lack in technology education, therefore they recognize the needs of reinforcement of engineering contents. Second, most technology teachers perceive that present technology subject does not give positive affect to students for their own career selection on engineering field. Furthermore, they perceive that if it contained the contents of engineering in technology education, students would experience creative design and problem solving process. Third, most technology teachers perceive that they are able to teach engineering in technology education and they need the change of national curriculum and the development of engineering program contents. Fourth, they perceive that the 7~9 grade is the best grade to start to study engineering in elementary and secondary school. Fifth, they perceive that 'design', 'problem solving' and 'creative thinking' are the priority of educational needs of teaching ability and knowledge about engineering. Sixth, they perceive that the aerospace engineering, the electrical engineering, the electronic engineering, the mechanical engineering, the computer engineering and the environmental engineering are the priority of educational needs of teaching knowledge about engineering fields.