• Journal of the Semiconductor & Display Technology
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• v.18 no.2
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• pp.23-28
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• 2019

Wire breakage in drawing, which is the most critical process in glass fiber manufacturing, is caused by numerous factors such as height, drawing speed, and air flow. The vibrations of the draw tower, however, is the most dominant factor to create the wire breakage. In this study, the structure of a draw tower has been analyzed through experiments and computer simulations to figure out the main reasons of the vibrations. And the design alterations were applied to the machine to identify the effects of those alterations. The result shows that design alterations of the draw tower structure can suppress the 87% of the vibrations, and further can prevent the wire breakage.

• Journal of Engineering Education Research
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• v.13 no.2
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• pp.3-6
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• 2010

In this paper, we report a case study of applying puzzle solving as a programming practice. There are many students, who have attended computer programming language courses, have had difficulties in accomplishing the course assignments. It is because just following and citing the programming language course materials is not sufficient for constructing computer programs. Many professional developers have stated that computer programming for small problems is an art of puzzle solving, where developing enterprise-size computer programming projects involves architectural insights which are already dealt in software engineering literatures. Following those backgrounds, we have explored the applicability of puzzle solving in a C++ object oriented programming course and have reported the results. The experimental results show that puzzle solving is effective to the students who are interested in computer programming and have at least beginner-level knowledge and expertise, but it turned out that puzzle solving assignments still does not draw much attention of the students who are not seriously interested in computer programming.

• Journal of the Optical Society of Korea
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• v.17 no.4
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• pp.300-304
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• 2013

Novel breakthrough random-hole optical fibers (RHOFs) are fabricated in a draw tower facility, by tapering an optical fiber preform packed with a silica powder mixture capable of producing air holes in situ at the high temperature of tens of hundreds in degrees Celsius. Structural and propagation characteristics of the porous RHOF are explained briefly. Experimental investigations of the invented RHOF are performed for pressure sensor applications. Remarkable results are obtained for the RHOF with desirable pressure sensitivity independent of temperature, as is required for harsh conditions as in oil reservoirs.

• Journal of the Optical Society of Korea
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• v.12 no.1
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• pp.19-24
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• 2008

In this paper, we describe the fabrication process and the characteristics of polarization maintaining photonic crystal fibers (PM-PCFs). The PM-PCF is fabricated by stack-and-draw method, i.e., stacking silica capillary tubes (making a PM-PCF preform) and drawing to optical fiber. Firstly, a PM-PCF preform is formed by stacking two kinds of capillary tubes around a solid silica rod and jacketing these stacked tubes with an outer silica tube (out-jacket tube). Later, the desired preform is drawn to a fiber in a high temperature drawing tower. We also compare the polarization properties such as polarization dependent loss, birefringence, and differential group delay of the fabricated PM-PCF with those of the conventional PANDA PM fiber.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.378-389
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• 2018

This study is intended to comprehend the level of Crisis management through the review of the government Crisis management system, to draw its problems and improvement methods, and to present implications on the establishment of effective Crisis management systems for the future. For this, the condition of operating Crisis management system was analyzed based on legal system, organizations and networks through the major disaster cases during Park Geun-hye administration period. The result of the study showed that there was lack of the interconnectedness among laws in the legal system, manuals and disaster preparation training. The Crisis management organizations had such problems as inappropriate response to crisis, perfunctory re-organization and lack of organizations' functions. The problems in the networks were relations between central and local governments, lack of cooperation and association among each division, and operation methods. The presented improvements for the above problems were the comprehensive revision of legal system, securing responsiveness of Crisis management organizations and the establishment of organic network system.