• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04a
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• pp.88-95
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• 2002

Recent development in the field of RE-Ba-Cu-O (REBCO, RE: Y or rare earth elements) bulk high-Tc superconductors (HTS) is reviewed in the present paper. After the fatal weak link problem of sintered REBCO superconductors has been overcome by melt processing, this field has been greatly advanced during last ten years. The critical current density $J_c$ at 77 K has been enhanced by introducing effective flux pinning sites into the $REBa_2Cu_3O_y$ (RE123) superconducting matrix. Large melt-textured REBCO bulk crystals have been fabricated with the TSMG(top-seeded melt growth) technique. Mechanical properties of REBCO bulks have been improved by using the Ag additive or epoxy resin. Real bulk applications such as current lead, fault current limiter, flywheel energy storage system, magnetic field source, magnetic separation system, and etc., surely come true near future.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.7
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• pp.696-705
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• 1991

This paper describes the procedures for pre-tuning and re-tuning the gains of PI controller based on output patterns -output error integral- of the unknown process which may not have any information, for example, system order, deadtime, time constant, etc. The key ideas of the proposed adaptive scheme are as follows. The scheme determines the initial gains by using ZNM (Ziegler-Nichols Method) with relay feedback, and then the adaptive algorithms by pattern recognition are introduced for re-runing the PI gains with on-line scheme whenever control conditions are changed. Because, among the various auto-tuning procedures, ANM with relay feedback has the difficulty in re-tuning with on-line and Bristol method has no comment on initial settings and has variables to pre-determine, which makes the algorithm comples, the proposed methods have the combined scheme with above two procedures to recover those problems. And this paper proposes a simple way to determine adaptive constant in Bristol method. To show the validity of the proposed method, an example is illustrated by computer simulation and a laboratory process, heat exchanger, is experimented.

• Journal of The Korea Institute of Healthcare Architecture
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• v.11 no.1
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• pp.43-54
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• 2005

This study is a second paper of the re-structuring strategies of healthcare facilities in Kwang-ju and Jeon-nam province for it's competition power in the emerging global health care market. Kwang-Ju city and Jeon-nam province have had difficulties in building a balanced healthcare system because of rapidly declining population, weakened healthcare infra-structure and geographical problems of healthcare supply by numerous islands. This paper presents the new approaching process for re-building healthcare network in the regional healthcare facilities planning. In addition, it analyzes health planning index, healthcare system, the concept of health care networking, etc. Finally, this presents the case study of regional healthcare facilities planning in Kwang-ju city and Jeon-nam Province.

• Journal of the Korean Solar Energy Society
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• v.35 no.6
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• pp.25-33
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• 2015

In this study, heating performance of the air-cooled heat pump with vapor-injection (VI) cycles, re-heater and solar heat storage tank was investigated experimentally. Devices used in the experiment were comprised of a VI compressor, re-heater, economizer, variable evaporator, flat-plate solar collector for hot water, thermal storage tank, etc. As working fluid, refrigerant R410A for heat pump and propylene glycol (PG) for solar collector were used. In this experiment, heating performance was compared by three cycles, A, B and C. In case of Cycle B, heat exchange was conducted between VI suction refrigerant and inlet refrigerant of condenser by re-heater (Re-heater in Fig. 3, No. 3) (Cycle B), and Cycle A was not use re-heater on the same operating conditions. In case of Cycle C, outlet refrigerant from evaporator go to thermal storage tank for getting a thermal energy from solar thermal storage tank while re-heater also used. As a result, Cycle C reached the target temperature of water in a shorter time than Cycle B and Cycle A. In addition, it was founded that, as for the coefficient of heating performance($COP_h$), the performance in Cycle C was improved by 13.6% higher than the performance of Cycle B shown the average $COP_h$ of 3.0 and by 18.9% higher than the performance of Cycle A shown the average $COP_h$ of 2.86. From this results, It was confirmed that the performance of heat pump system with refrigerant re-heater and VI cycle can be improved by applying solar thermal energy as an auxiliary heat source.

• Journal of Science Education
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• v.37 no.1
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• pp.221-232
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• 2013

The purpose of this study was to examine the effect of the CoRe-based density unit class on conceptual formation and on learner satisfaction with the class. For this study, two hundred and forty 8th grade students were chosen from six classes. The students were divided into two groups: an experimental group, which received a CoRe-based density unit lesson, and a control group, which was taught based on traditional teaching method. The CoRe-based density unit classes consisted of 4 periods based on the analysis of the previous studies on CoRe about density. The results showed the meaningful significant difference between the CoRe-based classes and the classes based on traditional teaching method both in the posttest on the extent of the conceptual formation on the density and in the retention test. The difference suggests that the lesson with CoRe is based on the consideration of the difficulties and limitations students face in various fields such as the students themselves, teachers, learning environment, evaluation, etc. during their learning process and even in the types of preconception they have, and the CoRe-based lesson is centered around the best teaching strategies to solve such difficulties. As a result of the analysis on the experimental group's class satisfaction, it is revealed that the students with a high level of attitudes related science or with a high level of science achievement showed especially high satisfaction in their learning. Analysis of questionnaire survey showed that the students in the experimental group got the opportunity through CoRe-based lesson to stretch their thoughts and ideas in a free way and preferred a teaching method which didn't just show the concept, but allowed them to find it for themselves or which let them predict the solution and then confirm the result on their own and a lesson which encouraged their active participation.

• Korean Journal of Oriental Medicine
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• v.18 no.3
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• pp.31-38
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• 2012

Jo Taek-seung(曺澤承, 1841-1907), who devoted himself to medical science mostly living in Haenam, and his son Jo Byeong-hu(曺秉侯, 1869-?) are significant in the history of Korean oriental medicine. The medical science of Jo Taek-seung appointed as Jusa(主事) of Hyeminwon(惠民院) in 1902 was handed down to his only son Jo Byeong-hu, who succeeded to his father's medicine and polished up the medicine, and recorded the results "Sanghangyeongheombangyochwal(傷寒經驗方要撮)" in 1933. Jo Taek-seung's portrait has been handed down to Jo Taek-seung's descendents' house in Munane-ri, Haeman. Not only does Jo Taek-seung's portraits well present the features of portrait mode of Joseon Dynasty period in the 19th century in their front view, exposure of two hands, expressive mode, background articles, etc, but also praises, poems, etc. giving information on manufacture intent, etc. to give prominence to the authors recorded by Jo Taek-seung, time of manufacture and position of medical official appears in one screen. In this paper, through disaster-removing poetic sentence showed in Jo Taek-seun'sg portraits, it was found that the author of the portrait is Choi Byeong-uk who worked mostly staying in Seoul and the present portrait was the one re-painted in 1907 by revising the portrait painted in 1894 when Jo Taek-seung was 54 years old, after Jo Taek-seung died. With regard to revised portion, presuming through records on the picture and comparative analysis of mode with portraits of doctors in the 20th century, it seems that the clothing of Confucian scholars in the first version was revised into the clothing of medical officials showing the position of Jo Taek-seung who took office as Jusa of Hyeminwon at the time of re-painting the portrait. Jo Taek-seung's portrait not only becomes important materials in the oriental medicine and historical world in the aspect of manufacture process, mode, etc. of Korean portraits including an aspect of medical official's portraits, but has significant meaning from the aspect of fine art history or clothing history.

• Korea-Australia Rheology Journal
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• v.21 no.4
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• pp.213-223
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• 2009

Taylor-Couette flow (i.e., flow between concentric, rotating cylinders) has long served as a paradigm for studies of hydrodynamic stability. For Newtonian fluids, the rich cascade of transitions from laminar, Couette flow to turbulent flow occurs through a set of well-characterized flow states (Taylor Vortex Flow, wavy Taylor vortices, modulated wavy vortices, etc.) that depend on the Reynolds numbers of both the inner and outer cylinders ($Re_i$ and $Re_o$). While extensive work has been done on (a) the effects of weak viscoelasticity on the first few transitions for $Re_o=0$ and (b) the effects of strong viscoelasticity in the limit of vanishing inertia ($Re_i$ and $Re_o$ both vanishing), the viscoelastic Taylor-Couette problem presents an enormous parameter space, much of which remains completely unexplored. Here we describe our recent experimental efforts to examine the effects of drag reducing polymers on the complete range of flow states observed in the Taylor-Couette problem. Of particular importance in the present work is 1) the rheological characterization of the test solutions via both shear and extensional (CaBER) rheometry, 2) the wide range of parameters examined, including $Re_i$, $Re_o$ and Elasticity number E1, and 3) the use of a consistent, conservative protocol for accessing flow states. We hope that by examining the stability changes for each flow state, we may gain insights into the importance of particular coherent structures in drag reduction, identify simple ways of screening new drag reducing additives, and improve our understanding of the mechanism of drag reduction.

• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.101-110
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• 2009

The 6LoWPAN(IPv6 Low-power Wireless Personal Area Network) performs IPv6 header compression, TCP/UDP/IGMP header compression, packet fragmentation and re-assemble to transmit IPv6 packet over IEEE 802,15.4 MAC/PHY. However, from the point of view of security. It has the existing security threats issued by IP packet fragmenting and reassembling, and new security threats issued by 6LoWPAN packet fragmenting and reassembling would be introduced additionally. If fragmented packets are retransmitted by replay attacks frequently, sensor nodes will be confronted with the communication disruption. This paper analysis security threats introduced by 6LoWPAN fragmenting and reassembling, and proposes a re-transmission mechanism that could minimize re-transmission to be issued by replay attacks. Re-transmission procedure and fragmented packet structure based on the 6LoWPAN standard(RFC4944) are designed. We estimate also re-transmission delay of the proposed mechanism. The mechanism utilizes timestamp, nonce, and checksum to protect replay attacks. It could minimize reassemble buffer overflow, waste of computing resource, node rebooting etc., by removing packet fragmentation and reassemble unnecessary.

• Journal of Welding and Joining
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• v.18 no.5
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• pp.70-76
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• 2000

The effect of Post Weld Heat Treatment(PWHT) of RE36 steel for marine structure was investigated with parameters such as micro-vickers hardness, corrosion potential and corrosion current density of weld metal(WM), base metal(BM) and heat affected zone(HAZ), and both Al alloy anode generating current and Al alloy anode weight loss quantity etc. Hardness of post-weld heat treated BM, WM and HAZ is lower than that of As-welded condition of each region. However, hardness of HAZ was the highest among those three parts regardless of PWHT temperature and corrosion potential of WM was the highest among those three parts without regard to temperature and corrosion potential of WM was the highest among those three parts without regard to PWHT temperature. The amplitude of corrosion potential difference of each other three parts at PWHT temperature $550^{\circ}C$, $650^{\circ}C$ are smaller than that of three parts by As-welded condition and corrosion current density obtained by PWHT was also smaller than that of As-welded condition. Eventually, it was known that corrosion resistance was increased by PWHT. However both Al anode generating current and anode weight loss quantity were also decreased by PWHT compare to As-welded condition when RE36 steel is cathodically protected by Al anode. Therefore, it is suggested that the optimum PWHT temperature with increasing corrosion resistance and cathodic protection effect is $550^{\circ}C$.

• Journal of Fashion Business
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• v.7 no.5
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• pp.17-31
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• 2003

$Premi\grave{e}re$ Vision is a leading textile collection held since 1973. In this study, textiles for 2004/05 F/W season in $Premi\grave{e}re$ Vision were analyzed at the various point of view, such as general trend, sub-theme, fiber content, color trend, structure, yarn trend, pattern, texture, decoration, finishing and other technical treatment, and functionality. There were three general trends; natural/ecology, geometry, and combination. Natural color and texture were widely used over the fabric exhibited, and irregularities expressed the natural trend of textiles. Geometric patterns were used for knit as well as for woven. Geometry expressed by various methods such as weaving, knitting, printing, shearing, embossing, and etc. However, geometry shown in this season was not a clear form expressed by weaving, but a blurry, irregular form expressed by various other methods such as knitting. The combination among heterogeneous fibers, yarns, colors, images, and textures was usual, however, the harmony among them was accomplished.