• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.38-45
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• 2006

The superconducting fault current limiters(SFCLs) provide the effect such as enhancement in power system reliability due to limiting the fault current within a few miliseconds. Among various SFCLs we have developed a flux-lock type SFCL and exploited a special design to effectively reduce the fault current according to properly adjustable magnetic field after the short-circuit test. This SFCL consists of two copper coils wound in parallel on the same iron core and a component using the YBCO thin film connected in series to the secondary copper coil. Meanwhile, operating characteristics can be controlled by adjusting the inductances and the winding directions of the coils. To analyze the operational characteristics, we compared closed-loop with open-loop iron core. When the applied voltage was 200[Vrms] in the additive polarity winding, the peak values of the line current the increased up to 30.71[A] in the closed-loop and 32.01[A] in the open-loop iron core, respectively. On the other hand, in the voltages generated at current limiting elements were 220.14[V] in the closed-loop and 142.73[V] in the opal-loop iron core during first-half cycle after fault instant under the same conditions. We confirmed that the open-loop iron core had lower power burden than in the closed-loop iron core. Consequently, we found that the structure of iron core enabled the flux-lock type SFCL at power system to have the flexibility.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1075-1078
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• 2015

Three kinds of typical practices to reflect the values of Agile Development Methodology were selected from a previous study. Those were Communicate using Web 2.0 collaboration tools, test-driven development (TDD, Test-Driven Development) method is adopted, and refactoring. In this study, we set up a hypothesis that the adoption of TDD project will make user satisfaction is higher. Select 100 sample projects from SourceForge(sourceforge.net), the most popular open source hosting site, the criteria is we can be determined whether operate in the project (developer least 7 people, bugs can occur more than 100, created the project since 2000). To determine whether the use of automated development tools xUnit of TDD through the CVS and SVN log analysis. Using data from the FLOSSmole and to evaluate the user experience of the project. User satisfaction of each project Rating, bug fix cycle, downloads and pageviews. Through this study, correlates of whether TDD adoption and user satisfaction, we will suggest a reflected the Agile practices new open source development methodology. As a result, it contributes to increase the maturity of the open source community.

• Advances in concrete construction
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• v.2 no.2
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• pp.109-123
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• 2014

This paper presents chloride induced corrosion durability of reinforcing steel in geopolymer concretes containing different contents of sodium silicate ($Na_2SiO_3$) and molarities of NaOH solutions. Seven series of mixes are considered in this study. The first series is ordinary Portland cement (OPC) concrete and is considered as the control mix. The rest six series are geopolymer concretes containing 14 and 16 molar NaOH and $Na_2SiO_3$ to NaOH ratios of 2.5, 3.0 and 3.5. In each series three lollypop specimens of 100 mm in diameter and 200 mm in length, each having one 12 mm diameter steel bar are considered for chloride induced corrosion study. The specimens are subjected to cyclic wetting and drying regime for two months. In wet cycle the specimens are immersed in water containing 3.5% (by wt.) NaCl salt for 4 days, while in dry cycle the specimens are placed in open air for three days. The corrosion activity is monitored by measuring the copper/copper sulphate ($Cu/CuSO_4$) half-cell potential according to ASTM C-876. The chloride penetration depth and sorptivity of all seven concretes are also measured. Results show that the geopolymer concretes exhibited better corrosion resistance than OPC concrete. The higher the amount of $Na_2SiO_3$ and higher the concentration of NaOH solutions the better the corrosion resistance of geopolymer concrete is. Similar behaviour is also observed in sorptivity and chloride penetration depth measurements. Generally, the geopolymer concretes exhibited lower sorptivity and chloride penetration depth than that of OPC concrete. Correlation between the sorptivity and the chloride penetration of geopolymer concretes is established. Correlations are also established between 28 days compressive strength and sorptivity and between 28 days compressive strength and chloride penetration of geopolymer concretes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.3094-3099
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• 2010

Modern urban cities are experiencing various problems like chronic traffic congestion, environmental pollution, reduced open space, shortage of affordable housing, deterioration of old downtown and sprawl. Under these circumstances, the urban sustainability can be grasped in many view points. Among these view points, urban growth management is one of the most recent and important issues that should be implemented by local government for the urban sustainability. This study will investigate the concept of Smart Growth as an executable strategy for the realization of sustainable urban growth management. On the other hand, one of the most important problems that hinder the urban sustainability is the lack of consistency in driving the sustainable strategy originated from the fragility of virtuous cycle of internal organizations themselves. This study will suggest an alternative local government organization model that enables the consistency and virtuous cycle of sustainable urban growth management based upon Regional Innovation System concept.

• Journal of Korean Academy of Nursing
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• v.29 no.6
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• pp.1263-1272
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• 1999

This study was alone to identify the meaning and the essence of the menopause experience by means of the Colaizzi’s phenomenological method. The participants were eight women, 48-60 years old, who were experiencing perimenopause or postmenopause. They were selected using a theoretical sampling technique. Data were collected through in-depth interviews from April 6 to May 20, 1999. The interviews took from 40 to 90 minutes. Interviews were tape- recorded and analyzed using the constant comparative method. Significant statements from data were extracted. From these formulated meanings, 18 themes, 8 clusters of themes and 3 catagories were constructed. Final descriptions were found to be valid through the interviewee validation process. Essential themes of the menopausal experience which emerged were “coming of change”, “inclined to deny the in mind”, and “adapted life”. Menopause, as coming of change was the turning point in the women’s life cycle acompaning changes, in body and mind and marital life changes. Especially, the unpredictable menopausal changes were an opportunity to hide the fact of menopause and not to talk with anybody. Such a phenomenon reflected on the psychological attributes of menopausal woman such as an inclination to deny in the mind. Their experiences of menopause as adapted life were generally regarded as signalling the end of fertility and were interpreted as a natural developmental process that indicates a life transition. In conclusion, participants depicted the menopause as a natural stage in the life cycle. In order to help women have a positive life change and self accomplishment, nurses need to understand the essential themes of the menopausal experience. Thus, the importance of an open approach in eliciting the phenomena of menopause cannot be overemphasized. In conclusion, the results of this study suggest that exercise program is one of the effective interventions to improve the self-efficacy and also to lower the fatigue in the sample of female college students.

• Clinical and Experimental Reproductive Medicine
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• v.20 no.1
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• pp.45-51
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• 1993

Micromanipulation procedures have been used to improve fertilization rates in patients with male factor or with unexplained infertility. Partial zona disseetion(PZD), a method using mechanical force to open the zona pellucida increase the chances of fertilization. The purpose of this study is to increase rates of fertilization and pregnacy in the ART program by using PZD. The influence of PZD on the fertilization rate was investigated in 57 couples with semen defects, antisperm antibodies(ASA), or unknown factors. PZD directly performed in 35 couples with a history of fertilization failure in previous cycle (Group 1), and PZD applied in 22 couples with the failure of initial fertilization in the same cycle (Group 2). The fertilization rates of the male facor, ASA positive factor and unknown factor in Group 1 were 37.6%, 20.0% and 59.2%, respectively. The rates of fertilization of male factor, ASA positive factor and unknown factor in Group 2 were 34.8%, 20.0% and 26.5%, respectively. The incidences of polyspermy in Group 1 and Group 2 were 5.9% and 9.0%, respectively. Among 35 patients of Group 1, one patient was pregnant and successfully delivered, whereas 1 of 22 patients of Group 2 became pregnant, but aborted at 7 weeks.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.29 no.4
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• pp.48-54
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• 2000

자성재료에 자기장을 걸어주변 가열되고 자기장을 제거하면 냉각되는 성질이 있는데, 이를 자기열량효과(magnetocaloric effect)라고 하며, 이것을 이용해서 저온을 생성시키는 방법을 자기냉동(magnetic refrigeration)이라고 한다. 큐리 온도(Curie temperature) 부근의 강자성체에 자 기장이 가해지면 전자례도내에서 쌍을 이루지 않은 전자들의 자기모벤트들이 자기장에 평행 하게 배열되는데, 이로 인해 열역학적 무질서의 척도인 엔트로피는 낮아지고 이러한 손실을 보상하기 위해 재료의 온도가 올라가게 된다.반대로 자기장이 제거되면 자기모벤트가 본래의 무질서한 상태로 돌아오며, 엔트로피가 증가하 고 재료의 온도는 떨어지게 되는 것이다. 역사적으로 보면 1881년에 Warburg가 큐리온도 부근의 철에서 자기열량효과를 처음 발견하였으며. 1926년과 1927년에 Debye와 Giauque가 각각 단열소자볍 (adiabatic demagnetization)을 제안함으로써 실용화되기 시작하여 주로 극저온을 얻는 방법으로 이용되어 왔다. 1950년도 이전의 연구는 절대온도 영도(OK)에 도달하고 자 하는 순수과학적인 노력으로서 개방사이클(open cycle)을 이용한 단열냉각 방식을 추구하 였으나, 1950년 이후부터는 공학적인 응용을 목적으로 밀폐사이클(closed cycle)을 형성하는 자기냉동기에 관한 연구가 진행되었다. 1976년에 Brown은 희토류(rare earth) 금속인 가돌리늄(Gd)을 사용하여 유체(물 80%와 에틸 알코올 20%)를 재생시킴으로써 상온에서 작동 하는 자기냉동기를 보고한 바 있다. 그는 7 T의 큰 자장을 이용하였으며, 고온부와 저온부의 온도는 각각 $46^{\circ}C와\;-1^{\circ}C로서\;47^{\circ}C$의 온도간격을 얻었다. 자기냉동에 있어서의 또 하나의 중요한 진전은 1978년과 1982년에 Steyert와 Barclay에 의해서 능동자기재생기(active magnetic r regenerator)의 개념이 소개되고 개발된 것으로, 이는 자성재료가 냉매로서 뿐만 아니라 열전달 유체의 재생기로도 사용되는 방식이다. 이상과 같은 자기냉동기술의 발달에 이어서 1997년에 미국의 Astronautics사(Wisconsin주 Madison시 소재)와 Ames 연구소(Iowa주 Ames 시 소재)의 공동연구팀이 발표한 두 가지의 새로운 진전으로 인해 공기조화 및 냉동분야에 적용할 수 있는 자기냉동기의 실용화 가능성이 한층 높아졌다. 이들의 연구결과는 (1) 자기냉동이 실온에서도 실현 가능한 기술이며 증기압 축식 냉동에 필적할 만하다는 것을 보인 것과 (2) 이미 알려져 있던 자기냉동재료보다 자기 열량효과가 훨씬 큰 새로운 재료를 발견한 것이다. 이로써 자기냉동에 대한 관심과 기대가 한결 커지고 있다. 본 원고에서는 자기냉동의 원리가 되는 자기열량효과와 이를 이용한 자기냉동의 방법 그리고 최근에 이루어진 새로운 진전에 대해 소개하고 공기조화 및 냉동분야에의 적용 가능성을 전망해 보고자 한다.

• Research in Community and Public Health Nursing
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• v.13 no.3
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• pp.503-512
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• 2002

Purpose: This study was conducted to develop educational materials for preventing type B viral hepatitis infection. Prior to this study, a survey had been conducted to define the educational needs of persons with hepatitis B antigen. Method: Based on the results of the former study and a review of the literature, the content of the educational materials was confined to the transmission cycle and its prevention in type B hepatitis. A professional team that consisted of writers and producers videotaped the lectures provided by professors and instructors in a nursing school. A professional graphic designer produced the leaflet to enhance the visual effects. Results: The contents of the educational materials for type B hepatitis were composed of six parts: (1) the prevalence rate (or morbidity) of type B hepatitis antigen positive and its recent trend, (2) transformation of hepatitis. (3) transmission cycle of hepatitis infection, (4) persons who are susceptible to hepatitis and need a vaccination, (5) preventive approach hepatitis vaccination and the guideline for patients' daily lives for preventing infection and (6) questions and answers. The materials were delivered in the form of lectures, visual charts, graphics, and multi-media. Conclusion: The educational materials developed in this study may provide practical information and knowledge on strategies to prevent type B hepatitis. The educational materials may be utilized in primary health care centers or school health services.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1377-1386
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• 2015

GDP gap is closely related with economic activity of a country as a whole, especially with the economic fluctuations which is called business cycle. GDP gap is regarded as an important variable for the monetary policy of the central bank because it provides information on the excess demand pressures and employment matters. However, GDP gap may not provide enough information of the effect of recent economic structural change or the environmental change of domestic and external economic condition. In this paper, the GDP is decomposed by statistical filtering techniques and various models are fitted to estimate the influence of GDP gap on Inflation and see if it has been changed. Analysis results show that the influence of GDP gap on inflation decreased in the 2000s while that of global GDP gap increased. These results also support that recent low inflation rate is due to the change of overseas economic condition, such as a slowdown in exports resulting from the global recession, as well as domestic factors.

• Journal of Korean Society of Archives and Records Management
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• v.16 no.1
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• pp.89-120
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• 2016

This study aims to understand the concept and changes of the records management of InterPARES based on the analysis of background, main research interests, and major achievements of IP3 and ITrust. To this end, this study conducted a content analysis of IP3 and ITrust to drive main keywords. This study also utilized word clouds from IP project titles. In addition, a comparative analysis of IP3 and ITrust was conducted based on the environment, scope, core research areas, keywords, objectives, and record management life cycle perspectives. The research identified that InterPARES research was widely expanding the content and subject areas of the study: 1) to apply across the life cycle, as well as long-term preservation; 2) to focus on the concept of trust as well as the concept of authenticity; and 3) to include the concept of the Internet, digital forensics, and the open government along with electronic records.