• Journal of the Korean BIBLIA Society for library and Information Science
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• v.25 no.2
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• pp.77-95
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• 2014

The purpose of this study is to analyze ego state types of teacher librarians by using egogram of the Transactional Analysis. It is the ideal ego state types for teachers that NP (Nurturing Parent), A (Adult) and FC (Free Child) are much higher than CP (Critical Parent) and AC (Adapted Child). But the teacher librarians are under higher CP and AC rather than A and FC. It means that the teacher librarians consider their values and belief as right things. Also it seams that they have not a conciliatory attitude but a hardened attitude that emphasize rules and standards. These ego state may be obstacle to their instructors role under the constructivist learning environment highlighting self directed learning of students. So, in the training course for the teacher librarians, informational and educational service course and development programs of education contents and instructional materials should be reinforced in order to strengthen their teaching competence and partnerships.

• Journal of Korean Association for Spatial Structures
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• v.12 no.1
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• pp.69-75
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• 2012

The purpose of this paper is to study comparative analysis of cable dome structures by reinforcement effect with bracing and fabric. Tensegrity systems are stable structures which are reticulated spatial structures composed of compressive straight members, struts, and cables. Tensegrity structures need to be introduced to the initial stress for the self-equilibrated system to have a stable state. In this paper, the effect of reinforcement resisting the in-plan twisting is investigated for the Geiger-type and Zetlin-type models reinforced by bracing and fabric. The effect of initial imperfection is also studied because the structural instabilitity phenomenon of shell-like structures is very sensitive according to the initial condition. We study a more exact analysis concerning the structural instability of tensegrity structures using nonlinear analysis program. Then, two types of tensegrity models will be analysed and compared.

• Elastomers and Composites
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• v.53 no.3
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• pp.175-180
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• 2018

Solution-styrene-butadiene rubber (SSBR) composites were manufactured using four kinds of fillers: silica-silane coated carbon black (SC-CB) hybrid, starch-SC-CB hybrid, pure silica, and pure starch. The influence of filler type on the mechanical properties of the rubber matrix was studied in this work. SC-CB was prepared by silane-graft-coating using vinyl triethoxy silane and carbon black, which enhanced the dispersion effect between the rubber matrix and the filler, and improved the mechanical properties of the compounds. The morphology of the composites was observed by field-emission scanning electron microscopy (FE-SEM). The thermal decomposition behavior of the composites was determined by thermogravimetric analysis (TGA), and the crosslinking behavior of the composites was tested using a rubber process analyzer (RPA). The hardness, tensile strength, swelling ratio, and gas transmittance rate of the composites were evaluated according to ASTM. The test results revealed that with the addition of SC-CB, the hybrid fillers, especially those blended with silica, showed a better reinforcement effect, the highest hardness and tensile strength, and stable thermal decomposition behavior. This implies that the silica-SC-CB hybrid filler has a notable mechanical reinforcement effect on the SSBR matrix. Because of self-crosslinking during its synthesis, the starch-SC-CB hybrid filler produced the most dense matrix, which improved the anti-gas transmittance property. The composites with the hybrid fillers had better anti-swelling properties as compared to the neat SSBR composite, which was due to the hydrophilicity of silica and starch.

• Journal of Science and Technology Studies
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• v.12 no.1
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• pp.79-106
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• 2012

The paper discusses the issue of reality related to interaction between users and electronic figures that mediate by online game system. MMORPG(Massively Multiple Online Role Playing Game) has been known as virtual world that physically and electronically interconnect users and mechanical elements over huge area. Already game items have became a kind of reality for some users long time ago. How these figures could have been regarded as realities? It suggests to take place the temporality of practice around game world. Tremendous practices of human and machines produce their relations and these relations are reinforced self-referentialy. They could constitute their time-space frame that be situated a figure as the something in it.

• Journal of the Korea Concrete Institute
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• v.13 no.2
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• pp.146-152
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• 2001

The fractal geometry is a non-Euclidean geometry which discribes the naturally irregular or fragmented shaps, so that it can be applied to fracture behavior of materials to investigate the fracture process. Fractal curves have a characteristic that represents a self-similarity as an invariant based on the fractal dimension. This fractal geometry was applied to the crack growth of cementitious composites in order to correlate the fracture behavior to microstructures of cemposite composites. The purpose of this study was to find relationships between fractal dimensions and fracture energy. Fracture test was carried out in order to investigate the fracture behavior of plain and fiber reinforced cement composites. The load-CMOD curve and fracture energy of the beams were observed under the three point loading system. The crack profiles were obtained by the image processing system. Box counting method was used to determine the fractal dimension, D$_{f}$. It was known that the linear correlation exists between fractal dimension and fracture energy of the cement composites. The implications of the fractal nature for the crack growth behavior on the fracture energy, G$_{f}$ is appearent.ent.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.2
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• pp.88-93
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• 2005

To develop a 100 hp high temperature superconducting(HTS) motor with high efficiency first in Korea, we fabricated a HTS field winding and test. HTS field winding is composed of sixteen HTS race track shaped coils wound with stainless steel-reinforced Bi-2223 tape conductor by react and wind fabrication method. Nomex paper was used for electrical insulation. Each of four magnet pole assemblies was constructed with four double pancake sub-coils, mechanically stacked and electrically in series. Four magnet assemblies were fixed on an aluminum support structure to make effective heat transfer. The Critical current (Ic) was 41.5A at 77K and self field. However the lowest Ic value of sub-coils was 35A. Joule heat generated by each joints between sub-coils was lower than 1mW at 77K and 34A. And Joule heat generated by the joints between field coils was lower than 10mW at 77K and 34A. Joule heat of the whole field winding was 1W at 77K and 32A. And so, the lowest Ic value of sub-coils was more important than Joule heats generated by all joints. The operating current must be lower than the lowest Ic of all the sub-coils. In this paper, design, construction and testing of HTS field winding, Joule heat generated by the joints, and operating current were discussed.

• Journal of the Korean GEO-environmental Society
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• v.9 no.2
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• pp.47-59
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• 2008

Application of mechanically stabilized earth wall (MSEW) abutment has been rapidly increasing in United States of America, Pennsylvania since 2002. MSEW is effective for reducing construction cost and period compared to general concrete reinforced wall. In the paper, theoretical background and conventional criterion of MSEW abutment that is widely used abroad are analyzed. Based on the results, application of suitable MSEW abutment to domestic bridge type is examined. For the application of MSEW abutment in Korea, load interacting with upper shoe in domestic bridge types and structural analyses of beam seat and pile are investigated. As a result, all applications are possible except for PSC BOX Bridge that has heavy self-weight of girder. Through two and three dimensional numerical analyses, horizontal behaviour mechanisms between pile and MSEW were analyzed and field tests are also carried out for seven piles behind earth walls. From results of field tests, it is confirmed that an angle of internal friction of backfill material needs to be greater than 34 degree to use H-Pile as foundation of MSEW.

• Korean Journal of Community Nutrition
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• v.22 no.1
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• pp.40-52
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• 2017

Objectives: This study was conducted to examine the length of exposure to smartphone and its association with dietary behavior toward snacks, lifestyle, and nutrition knowledge in elementary school students. Methods: Subjects were 372 5th and 6th grade schoolchildren in Cheongju, Korea, and data was collected by a self-administered questionnaire. They were divided into two groups by the time spent using smartphone: moderate (< 2 hours/day) and overexposure (${\geq}2$ hours/day). Data was analyzed using frequency analysis, ${\chi}^2$-test, and independent t-test as well as analysis of covariance when necessary. Results: Approximately half of subjects (41.4%) reported spending ${\geq}2$ hours/day using smartphone. That habit was more frequent among students in the 6th grade, those who received more monthly allowance, and who has a working mother. 63.4% of the subjects reported that they consumed snacks while watching television, using a computer and/or a smartphone and 48.1% said that they consumed snacks while they use a smartphone. Both situations were most prevalent among those with overexposure to smartphone (${\geq}2$ hours/day). We also observed that a higher percentage of subjects from the overexposure group spent more money on snack foods with the preference for ice cream, fast food, and carbonated drinks. Further, those in the overexposure group consumed more ice cream, cookies, and carbonated drinks. In addition, they had less desirable dietary behavior and health-related lifestyle (sleep duration and frequency of regular exercise) compared to those with moderate smartphone usage (< 2 hours/day). However, there was no statistical difference in nutrition knowledge among children with different degrees of smartphone usage. Conclusions: Our results showed that longer smartphone use was associated with less desirable snack preference/consumption and other dietary behavior in elementary school students. Thus interest and positive attitudes towards healthy snacks and diet should be reinforced in nutrition education programs, especially for those who are prone to use smartphones.

• Transactions of Materials Processing
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• v.23 no.5
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• pp.289-296
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• 2014

Uniaxial tensile tests were conducted to accurately evaluate the in-plane mechanical properties of fiber metal laminates (FMLs). The FMLs in the current study are comprised of a layer of self-reinforced polypropylene (SRPP) sandwiched between two layers of aluminum alloy 5052-H34. The nonlinear tensile behavior of the FMLs under in-plane loading conditions was investigated using both numerical simulations and a theoretical analysis. The numerical simulation was based on finite element modeling using the ABAQUS/Explicit code and the theoretical constitutive model was based on the volume fraction approach using the rule of mixture and a modification of the classical lamination theory, which incorporates the elastic-plastic behavior of the aluminum alloy and the SRPP. The simulations and the model are used to predict the inplane mechanical properties such as stress-strain response and deformation behavior of the FMLs. In addition, a post-stretching process is used to reduce the thermal residual stresses before uniaxial tensile testing of the FMLs. Through comparison of both the numerical simulations and the theoretical analysis with the experimental results, it is concluded that the numerical simulation model and the theoretical approach can describe with sufficient accuracy the actual tensile stress-strain behavior of the FMLs.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.820-830
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• 1989

The tire inflation and contact problem has been solved by a finite element method. The finite element formulation is derived from the equilibrium equations by the principle of virtual work in the form of an updated Lagrangian formulation for incremental analysis. Then, a contact formulation is added to the finite element formulation to calculate stress state of tire in contact with flat rigid road under the load due to the self-weight of a vehicle. In the finite element analysis, equations of effective material properties are introduced to analyze a plane strain model of the shell-like tire by considering the bending effect of reinforced steel cords. The proposed equations of effective material properties produced stress concentration around the edge of belt layers, which does not appear when other well-known equations of material properties are adopted. The result from the above algorithm demonstrates the validity of the formulation and the proposed equations for the effective elastic constants. The result fully interprets the cause of separation between belt layers by showing the stress concentration.