• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.92-100
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• 2015

For the purpose of improving the efficiency of the radiation impact assessment of dry interim storage facilities for the spent nuclear fuel of pressurized water reactors (PWRs), radiation impact assessment was performed after the application of sensitivity assessment according to the radiation source term designation method, development of a 2-step calculation technique, and cooling time credit. The present study successively designated radiation source terms in accordance with the cask arrangement order in the shielding building, assessed sensitivity, which affects direct dose, and confirmed that the radiation dosage of the external walls of the shielding building was dominantly affected by the two columns closest to the internal walls. In addition, in the case in which shielding buildings were introduced into storage facilities, the present study established and assessed the 2-step calculation technique, which can reduce the immense computational analysis time. Consequently, results similar to those from existing calculations were derived in approximately half the analysis time. Finally, when radiation source terms were established by adding the storage period of the storage casks successively stored in the storage facilities and the cooling period of the spent nuclear fuel, the radiation dose of the external walls of the buildings was confirmed to be approximately 40% lower than the calculated values; the cooling period was established as being identical. The present study was conducted to improve the efficiency of the Monte Carlo shielding analysis method for radiation impact assessment of interim storage facilities. If reliability is improved through the assessment of more diverse cases, the results of the present study can be used for the design of storage facilities and the establishment of site boundary standards.

• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.681-694
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• 2021

This study is aimed to investigate the effects of perceived value of the users in the relationship between service qualities of the Pilates training centers, which has been recently increasing, and their reuse intention. A survey research was conducted with 487 users who used the Pilates training centers and collected data were analyzed using SPSS 23.0 and AMOS 23.0 programs. The analysis results are as follows. First, service qualities perceived by the Pilates users including external service, quality of trainers, training program, and tuition fee showed significant impact on reuse intention, positively. Second, service qualities perceived by the Pilates users including external service, quality of trainers, training program, and tuition fee showed significant impact on both functional and emotional values, positively. Third, functional and emotional values perceived by the Pilates users showed significant impact on reuse intention, positively. Fourth, significant mediating effect of functional value was found in the relationship between service qualities of the Pilates training centers, which were external service, quality of trainers, training program, and tuition fee, and reuse intention. Fifth, significant mediating effect of emotional value was found in the relationship between service qualities of the Pilates training centers including training program and tuition fee, and reuse intention.

• Journal of Venture Innovation
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• v.4 no.3
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• pp.17-30
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• 2021

Environmental deterministic perspectives and resource-based perspectives have different perceptions on the factors that determine corporate performance. While the environmental deterministic viewpoint sees the external environment as having a significant impact on corporate performance. On the other hand, the resource-compliant viewpoint believes that it is important to obtain the necessary resources through appropriate decision-making in order to overcome the uncertainty of the environment. Although the external environmental impact on corporate performance is important, the study is in the position that efforts within the company to cope with environmental uncertainty are necessary. This study identified the role that factors within the company play in the process of affecting the external environment of the company's performance. This study looked at whether the CEO's innovation direction plays an mediating role in the market environment favorability affecting sales growth rate. The data was collected using a survey method. We collected data from 138 small and medium-sized manufacturing companies in Gyeongin area. The collected data was analyzed using SPSS 22 packages. According to the analysis, market environment favorability positively affects sales growth rate, and the CEO's innovation direction plays a mediating role between market environment favorability and sales growth rate. The results of this study showed that depending on the market environment, the CEO's interest and willingness to innovate, present a vision for innovation, and institutionalize innovation activities increase management performance through innovation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.9
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• pp.862-868
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• 2010

Development of a small scale aircraft has been carried out for the BASA(Bilateral Aviation Safety Agreement) program in Korea. This aircraft adopted all the composite structures for environmental friendly by low fuel consumption due to its lightness behavior. However the composite structure has s disadvantage which is very weak against impact due to foreign object damages. Therefore the aim of this study is focusing on the damage evaluation and repair techniques of the aircraft composite structure. The damages of composite laminates including the carbon/epoxy UD laminate and the carbon/epoxy fabric face sheets-honeycomb core sandwich laminate were simulated by a drop weight type impact test equipment and the damaged specimen were repaired using the external patch repair method after removing damaged area. The compressive strength test and analysis results after repairing the impact damaged specimens were compared with the compressive strength test and analysis results of undamaged specimens and impact damaged specimens. Finally, the strength recovery capability by repairing were investigated.

• Journal of KSNVE
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• v.5 no.4
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• pp.515-524
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• 1995

Tubes in heat exchanger of fuel rods in reactor core are supported at intemediate point by support p0lates or springs. Current practice is, in case of heat exchanger, to allow clearance between tube and support plate for design and manufacturing consideration. And in case of fuel rod the clearance in support point can be generated due to the support spring force relaxation. Flow-induced vibration of a tube can cause it to impact or rub against support plate or against adjacent tubes and can result in fretting-wear. The tube-to- support dynamic interaction is used to relate experimental wear data from single-span test rigs to real multi-span heat exchanger configurations. The dynamic interaction cna be measured during experimental wear tests. However, the dynamic interaction is difficult to measure in real heat exchangers and, therefore, analytical techniques are required to estimate this interaction. This paper describels the nonlinear impact model of DAGS(Dynamic Analysis of Gapped Structure) code which simulates the tube response to external sinusodial or step excitation and predicts tube motion and tube-to-support dynamic interaction. Three experimental measurements-two single span rods excited by sinusodial force and a two span rod impacted by a steel ball are compared from the simulation nonlinear model of DAGS code. The simulation results from DAGS code are in good agreement with measurements. Therefore, the developed model of DAGS code is good analytical tool for estimating tube-to-support dynamic interaction in real heat exchangers.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.217-223
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• 2012

This study describes an experimental investigation about the impact damage characteristics of various types of high speed train window glass. Kinds of impact test standards for glass were studied and impact test considering scattering ballast were developed. Windows with external impact side made with annealed, heat strengthened and tempered glasses are likely to be broken by sharp tipped falling object. Broken shape of annealed glass is like line in part and that of heat strengthened glass is line on the whole. Tempered glass is destroyed to pieces. The change of tip type from sharp to blunt makes the higher destroyed level. Tempered glass has higher strength than annealed glass with blunt tip. When the protective films are attached to glasses, strength against destruction increases. In case of real ballast test, glasses without protective films were destroyed, but those with protective films are hard to be broken.

• Composites Research
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• v.36 no.1
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• pp.25-31
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• 2023

Composite structures have been designed by stacking the laminae with different stacking angles to meet the required mechanical performance. Although the induced stresses on the composite structures under the external loads usually differ depending on the location, we determined the stacking sequence based on the maximum stress, which leads to low efficiency and generally is not the optimum design. Recently, piecewise integrated composites (PICs) were suggested for solving this inefficiency. PICs assume the perfect bonding between adjacent pieces, but this is ideal and hard to accomplish. Therefore, the overlap at the boundary is essential to prevent separation from each other. In this study, we investigated the effect of the overlap design on the impact failure mode of PIC plates. We fabricated the sample composite plates with different overlap designs using the fast curing carbon prepreg and conducted the impact tests according to ASTM D 7136. We found that PICs had different failure modes according to the overlap design, which lead the changes of absorbed impact energies as well as impact load curves.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.563-566
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• 2000

Recently vehicle development trend puts emphasis on cost reduction and performance improvement through weight reduction, and safety security to protect passenger and chassis against external impact. Primary factors effected on vehicle safety are chassis structure, chassis system, and safety equipment like bumper. Research in part of weight reduction is proceeding actively about prohibition of over-design and material through optimal design method. Bumper in these factors is demanded two of all factors, safety security and weight reduction. It is the part that prohibits or reduces a physical impact in low speed crash. Bumper is composed of a few parts but this study exhibits the shape of bumper rail has a role on energy absorption of safety security and weight reduction from structure analysis of bumper rail's variable shape surface.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.511-516
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• 2007

Rubber wheeled AGT(Automated Guide-way Transit) system is a prominence transportation system for urban area, because of its low construction cost and management, low noise and vibration and fine exterior view. AGT system uses concrete tracks. Concrete can be easily damaged by the impact, change of temperature and external loads. The fault of concrete track is harmful not only to riding quality but also to bridge. Therefore, in this study, the effects of railway prominence to the bridge are surveyed by experimental method. The experiment was executed for PSC bridge at AGT test line in Kyungsan. And the test results for 5mm, 10mm prominence and without prominence are compared and investigated, according to the vehicle speed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.5
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• pp.430-436
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• 2011

The purpose of this study is to analyze the vibration and sound generation characteristics of the sandwich panel. Two thick panels were assumed to be separated by a compliant viscoelastic core. The transverse vibration induced by an external impact was analyzed using the Rayleigh-Ritz method. For applying arbitrary boundary condition of the panels, the edges were assumed to be supported by the translational and rotational springs. The beam functions were used as the trial functions. The effect of the boundary condition and viscoelastic core on the resulting vibration characteristics was investigated. The radiated sound power was analyzed using the proposed numerical model and the Rayleigh integral. The dynamic properties of the core and the mass-stiffness-mass resonance frequency had significant influence on the impact sound.