• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.08a
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• pp.53-57
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• 2003

In order to make a doubly curved sheet metal effectively, a sheet metal farming process has been developed by adopting the flexibility of the incremental forming process and the principle of bending deformation which causes slight deformation to thickness. The developed process is an unconstrained forming process with no holder. For this study, the experimental equipment is set up with the roll set which consists of two pairs of support rolls and one center roll. In the experiments using aluminum sheets, it is found that the curvature of the formed sheet metal is determined by controlling the distance between supporting rolls in pairs and the forming depth of the center roll and it also depends on the thickness of the sheet metal. In order to check the effect of process parameters on the generation of sheet metal curvatures in this process, the orthogonal array is adopted. From the experimental results, among the process parameters, the distance between supporting rolls in pairs along the same direction of one principle radius of curvature as well as the forming depth and the thickness of the material is shown to influence the generation of curvature in the same direction significantly. That is, the other distance between supporting rolls in pairs which are not located in the same direction of one principle radius of curvature, does not have an significant effect on the generation of the curvature in that direction. It just affects the generation of curvature in its own direction mainly with the forming depth and the thickness of the material.

• Journal of Korean Library and Information Science Society
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• v.30 no.2
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• pp.1-28
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• 1999

This study aims to provide some rosie material for the libraries to improve its role for supporting the virtual university by recognizing the changing roles to have to support the distance education which is becoming a growing area in the coming new century due to the necessity of continuing renewal and the retaining of the information related workers. Through the study, a few conclusions were derived. (1) To support the virtual university, the library services should be directed toward the operation of the full access - philosophy and should reflect the information needs of the off-campus students. The librarians should be equipped with the ability to make use of networked resources and to provide the document delivery services together with the ability to develop the web-based user training programs. The department of library and Information Science should educate the future librarian for the purpose of supporting the virtual university. (2) A written and agreed guidelines should be established to specify the philosophy, management, facilities, resources and services to support the virtual university. And it is desirable that in the near future the department and a librarian responsible for the supporting the distance education should be established.

• Journal of the Korean Society for Railway
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• v.3 no.2
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• pp.51-61
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• 2000

In this study, field measurements of vibration on the structures supporting railroad track were performed. The vibration data obtained were analyzed to find out any correlation between its magnitude and several factors such as type of bridges, distance from the track, type of train, frequency characteristics, etc. As a result, the magnitude of vibration turned out to be the highest in the steel bridge, the concrete bridge and steel-concrete combined bridge were the next in descending order. It was also found that the dynamic characteristics of ground were the most important factors among several affecting vibration near by the railroad track. And the empirical ground vibration estimation equation for estimating ground vibration was developed. The proposed equation with respect to distances from the railroad could be easily used for the estimation of ground vibration at the residential areas nearby the track.

• Asian Journal of Innovation and Policy
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• v.9 no.2
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• pp.207-222
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• 2020

As the COVID-19 continues spreading, Korea's Ministry of Education (MOE) announced that all public schools, including elementary, middle, and high schools, must begin on April 9, 2020, via online teaching for the first time in the nation's history. There were opposite views among educators regarding the unprecedented attempt to start school online. This study intends to analyze the strategies and policies of distance learning in the public education sector using the experiences in Korea, which has been dealing with the COVID-19 pandemic over the past six months, and thus presents educational implications that may be of interest other countries in the post-COVID-19 era. This study first conceptualized the distance education policy in two domains: technological infrastructure and technological teaching and learning, and then examined what specific policies have supported distance education in school settings. For the analysis of policies supporting distance education in Korea, this study analyzed the relevant documents that include the annual plan and press release uploaded on the website of MOE from early March until early August. Accordingly, 13 documents that contain the distance education policy were analyzed in this study. To provide equal opportunities for all students and ensure fair resource allocations, technological inequality should be discussed in the context of educational inequality. Finally, this study looks at how strategies and policies could be related to educational equality and equity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.4227-4240
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• 2019

In this paper, we present our proposed magnetic induction based wireless communication system. The proposed system is designed to perform communication as well as distance measurement in underground environments. In order to improve the communication quality, we propose and implement the adaptive channel compensation technique. Based on the fact that the channel may be fast time-varying, we keep track of the channel status each time the data is received and accordingly compensate the channel coefficient for any change in the channel status. By using the proposed compensation technique, the developed platform can reliably communicate over distances of 10m while the packet error rate is being maintained under 5%. We also implement the distance measurement block that is useful for various applications that should promptly estimate the location of nearby nodes in communication. The distance between two nodes in communication is estimated by generating a table describing pairs of the magnetic signal strength and the corresponding distance. The experiment result shows that the platform can estimate the distance of a node located within 10m range with the measurement error less than 50cm.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.849-850
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• 2004

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.347-359
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• 2017

Blast resistant gates are required to be lightweight and able to mitigate extreme loading effect. This may be achieved through innovative design of a gate and its supporting frame. The first is well covered in literature while the latter is often overlooked. The design of supporting frame depends mainly on the boundary conditions and corresponding reaction forces. The later states the novelty and the aim of this paper, namely, the analysis of reaction forces in supporting structure of rectangular steel gates subjected to "far-field explosions". Flat steel plate was used as simplified gate structure, since the focus was on reaction forces rather than behaviour of gate itself. The analyses include both static and dynamic cases using analytical and numerical methods to emphasize the difference between both approaches, and provide some practical hints for engineers. The comprehensive study of reaction forces presented here, cover four different boundary conditions and three length to width ratios. Moreover, the effect of explosive charge and stand-off distance on reaction forces was also covered. The analyses presented can be used for a future design of a possible "blast absorbing supporting frame" which will increase the absorbing properties of the gate. This in return, may lead to lighter and more operational blast resistant gates.

• Geomechanics and Engineering
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• v.33 no.5
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• pp.507-518
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• 2023

The effects of various supporting arrangements have been investigated on an excavation support system using a numerical tool. The purpose of providing different supporting arrangements was to limit the pile wall deflection in the range of 0.5% to 1% of the excavation depth. Firstly, a deep excavation supported by sheet pile wall was modeled and the effects of sheet pile wall thickness, excavation depth and distance to adjacent footings from sheet pile wall face were explored on the soil deformation and wall deflection. Further analysis was performed considering six different arrangements of tieback anchors and struts in order to limit the wall deflections. Case-01 represents the basic excavation geometry supported by sheet pile wall only. In Case-02, sheet pile wall was supported by struts. Case-03 is a sheet pile wall supported by tieback anchors. Likewise, for the Cases 04, 05 and 06, different arrangements of struts and tieback anchors were used. Finally, the effects of different supporting arrangements on soil deformation, sheet pile wall deflection, bending moments and anchor forces have been presented.

• Journal of Korean Home Economics Education Association
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• v.19 no.2
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• pp.171-184
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• 2007

This research focused on the consciousness and behavior of married-teachers to support their aged-parents. The subject of this study was 239 married-teachers, in the Gyeongnam area, Korea, living with at least one of their old-parents. Statistical analysis was carried out using SPSS/WIN programs including frequencies, t-test, one-way ANOVA, correlation analysis and stepwise regression. The major findings in this study are as follows; 1) Degree of consciousness in supporting married-teachers' aged parents was 3.98 on a scale of 0-5.0. The significant variables affecting the results were sex, living-distance, and familism. 2) Degree of behavior in supporting married-teachers' aged parents was 3.07 on a scale of 0-4.0. The significant variables affecting the results were number of child, living-distance, economic level of aged parents, and self-esteem. 3) There was a close relationship between the consciousness and behavior of married-teachers to support their aged-parents. 4) Stepwise regression analysis showed that the most effective variable of the married-teachers' behavior for supporting aged-parents was supporting consciousness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.440-450
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• 2003

The reverse link of a spectrally overlaid macrocell/microcell cellular CDMA system supporting multimedia traffic is characterized in terms of the required signal power, interference, and capacity. Several narrowband subsystems are overlaid with a wideband subsystem in macrocells, while a single wideband subsystem is operated in a microcell with the same spectrum as the macrocell wideband subsystem. Using a typical propagation model the reverse link signal power and interference are characterized as the relative user signal power and the cross-tier interference factors between the macrocell and the microcell. The reverse link capacity of the overlay system is then analyzed. Analytical results show that the dominant parameters affecting the system performance are the spectral overlay ratio and the distance between the microcell and macrocell base stations. In particular, when the distance equals a half of macrocell radius, optimum performance can be achieved by minimizing the cross-tier interference factors. These results can be applied to CDMA multimedia network planning in heavily populated traffic areas.