• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.1067-1073
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• 2008

This study grasped the problem by examining the consciousness of professors about the e-Learning and reached a conclusion as follows. The understanding of the e-Learning in university should be reconsidered and diffused. To activate the e-Learning in university, the education system corresponding to course of the coming education should be introduced by hold the seminar and workshop periodically and establish vision and middle-short range policy for the e-Learning. Also, university should manage by characterizing a web-based class with the major for a learner hoping to take a cyber education course and propel contents development and interchange with a foreign university by concluding a convention for taking lectures having competitive power of an advanced country to make a worldwide university.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.32.1-32.7
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• 2019

Background: Tooth extraction commonly leads to loss of residual alveolar ridge, thus compromising the room available for the implant placement. To combat the post-extraction alveolar loss, alveolar ridge preservation is practiced, with the advent of the biomaterial available. The purpose of this study was to assess the efficiency of calcium phosphosilicate biomaterial in alveolar ridge preservation. Twenty patients indicated for extraction were selected followed by socket grafting using calcium phosphosilicate. Implant placement was done 6 months postoperatively during which a core was harvested from the preserved sockets. Clinico-radiographic measurements of hard and soft tissues were taken at baseline and 6 months post-grafting. Results: There were no significant changes in the radiographic and soft tissue parameters while significant changes in hard tissue parameters with 1.9 mm (p = 0.013) gain in mid-buccal aspect and 1.1 mm (p = 0.019) loss in horizontal bone width were observed. The histomorphometric evaluation depicted the vital bone volume of 54.5 ± 16.76%, non-mineralized tissue 43.50 ± 15.80%, and residual material 2.00 ± 3.37%. Conclusion: The implants placed in these preserved ridges presented 100% success rate with acceptable stability after a 1-year follow-up, concluding calcium phosphosilicate is a predictable biomaterial in alveolar ridge preservation.

• Journal of Digital Convergence
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• v.12 no.7
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• pp.247-252
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• 2014

Traffic network is composed of passing vehicls, delayed vehicles, traffic situation which is traffic incomes of traffic interfacing system. Traffic green time light is concluded by inside input factor, that is green light cycle, yellow light cycle, led light cycle, which light cycle is sensor inputs. That light cycle is converted to traffic phase composed of passing peoples and delayed vehicles, whose intervals is concluding of traffic network factors composed of consumptiom power factors, delayed time situation, occupying sensor nodes. This is very important sector,because of much poor traffic situation.

• Acta Via Serica
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• v.1 no.1
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• pp.33-50
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• 2016

The article studies the new situation in international long distance trade after the emergence of new superpower - Arab Caliphate - in Eurasian overland tracks of the Great Silk Road. The stages of Arab advancement along trade routes and outcomes of their contestation with the strong tribal confederations of Turkic nomads in Central Asia and the Caucasus are highlighted. A special focus is made upon the relationship of Arabs with Khazar Turks who have endured severe clashes with strongest army of the time in the region. Khazar kingdom survived and even expanded its control over the tracks of international trade in the western part of Eurasia. The research describes the way how trade partnership between Arabs and Turks was shaped in the aftermath of military clashes. Existing scholarly views on the role of Khazar in Silk Road are reviewed and unattended evidence of Arab sources are involved to support concluding points that Khazar state managed to consolidate various actors for maintenance of international trade such as so called Rus warriors and merchants in the west of Volga, nomadic tribes in Eurasian steppes, and Jewish trading gild named ar-rahdaniyya in Arab sources. It is asserted that Khazar state since the second half of 9th century through its decline in mid 10th century not only served as transit space for goods of exporting countries but also exported goods of its own crafts and natural resources.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1A
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• pp.16-22
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• 2006

This papers described with the analysis for electric Field strength on ground level transmitted from DMB transponder in stratosphere HAPS. It is compare with horizontal propagated ground wave. Resultly we confirm the equal strength a electric field on ground level between hish altitude vertical propagated wave and horizontal ground wave, also, is only 1W compare with terrestrial facility as transmitted output power for the DMB transponder in stratosphere HAPS. It is corresponding to 1Kw as same power value in ground propagated wave. Lastly it is new material wave source and also we concluding remarks as ubiquitous communication networking media.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.543-545
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• 2011

The concern which is abundant in MANET VoIP for comprising the mobility guarantee and mobile network is received without the infrastructure system between the mobile terminal node. However, because the access of system and border is easy, the issue which is big in the security problem becomes more than the wired network system with this convenience by the foreign network attacker differently. In this paper, we would like to the fundamental web network, NAT and concluding the security problem technology in which Firewall can inquire on MANET VoIP and whether it is appropriate or not which can solve this is proposed.

• KIEAE Journal
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• v.9 no.2
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• pp.65-71
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• 2009

Results from tests for what mixing rate of soil and sand is proper for the rammed earth and for how much additives are optimum are as under. 1) In the test to evaluate what mixing rate of soil and sand is desirable, peptizing property and surface sticking rate are found similar in its degree, but compression strength is found most stable when the ratio of soil and sand mixing shows 30:70 which indicates the best mixing rate of soil and sand. 2) In a test to add hydrated lime, compression strength, peptizing property, and surface sticking rate are found best when the mixing rate of soil and sand shows 23:7. 3) In a test to add sea weeds, the peptizing property goes down at 75% of sea weeds input a little bit more than at 100%, but compression strength shows best at 75% which is thought to be the best rate. 4) In a drop test, more soil powder mixed, the sticking strength gets better and more sands are contained, the sticking strength gets far worse to be scattered in powder type. 5) As concluding all results mentioned in the above item, the most desirable mixing rate of soil, sand, and hydrated lime is found to be 23:7:70 for the rammed earth where compression strength, peptizing property, and surface sticking rate are best.

• Journal of the Korean Institute of Educational Facilities
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• v.16 no.5
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• pp.27-33
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• 2009

The existing universities enlarged the scope, filled up the facilities. And many new universities are founded by increase of university students, the change of curriculum and extension of installations for new curriculum. However, the planning for university campus hinders desirable activities in campus and also the origin function of university, because of the problems caused by an application of a uniform planning standard that lacks in logical analysis and such a short step as the occasion demands for the growth and the change of the university campus changing more rapidly than any other field in society. This dissertation is for space program beginning from architectural explanation and basic planning concluding a general structure-planning for land utility, circulation planning, and building layout planning in order to find the practical solution for the applicable campus plan. The contents of this dissertation is summarized below. First, I studied the characteristics of the university, the structure of the university facilities and the expansion the development process of the campus. Second, through the case study of domestic campus planning, I analyzed the characteristics and the problems about space programming, facility layout planning, circulation planning and exterior space planning. Third, in the basis of the above analyses, I set up the directions of comprehensive campus master plan.

• Computers and Concrete
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• v.7 no.5
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• pp.469-482
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• 2010

This paper investigates the concrete permeability through a numerical and statistical approach. Concrete is considered as a random heterogeneous composite of three phases: aggregates, interfacial transition zones (ITZ) and matrix. The paper begins with some classical bound and estimate theories applied to concrete permeability and the influence of ITZ on these bound and estimate values is discussed. Numerical samples for permeability analysis are established through random aggregate structure (RAS) scheme, each numerical sample containing randomly distributed aggregates coated with ITZ and dispersed in a homogeneous matrix. The volumetric fraction of aggregates is fixed and the size distribution of aggregates observes Fuller's curve. Then finite element method is used to solve the steady permeation problem on 2D numerical samples and the overall permeability is deduced from flux-pressure relation. The impact of ITZ on overall permeability is analyzed in terms of ITZ width and contrast ratio between ITZ and matrix permeabilities. Hereafter, 3680 samples are generated for 23 sample sizes and 4 contrast ratios, and statistical analysis is performed on the permeability dispersion in terms of sample size and ITZ characteristics. By sample theory, the size of representative volume element (RVE) for permeability is then quantified considering sample realization number and expected error. Concluding remarks are provided for the impact of ITZ on concrete permeability and its statistical characteristics.

• Coupled systems mechanics
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• v.6 no.3
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• pp.335-349
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• 2017

To cope with the demand on giant and durable buildings, reinforcement of concrete is a practical problem being extensively investigated in the civil engineering field. Among various reinforcing techniques, fiber-reinforced concrete (FRC) has been proven to be an effective approach. In practice, such fibers include steel fibers, polyvinyl alcohol (PVA) fibers, polyacrylonitrile (PAN) carbon fibers and asbestos fibers, with the length scale ranging from centimeters to micrometers. When advancing such technique down to the nanoscale, it is noticed that carbon nanotubes (CNTs) are stronger than other fibers and can provide a better reinforcement to concrete. In the last decade, CNT-reinforced concrete attracts a lot of attentions in research. Despite high cost of CNTs at present, the growing availability of carbon materials might push the usage of CNTs into practice in the near future, making the reinforcement technique of great potential. A review of existing research works may constitute a conclusive reference and facilitate further developments. In reference to the recent experimental works, this paper reports some key evaluations on CNT-reinforced cementitious materials, covering FRC mechanism, CNT dispersion, CNT-cement structures, mechanical properties and fire safety. Emphasis is placed on the interplay between CNTs and calcium silicate hydrate (C-S-H) at the nanoscale. The relationship between the CNTs-cement structures and the mechanical enhancement, especially at a high-temperature condition, is discussed based on molecular dynamics simulations. After concluding remarks, challenges to improve the CNTs reinforcement technique are proposed.