• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.99-105
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• 2017

With the advancement of Information and Communication Technology (ICT), the wearable-device industry is growing at a rapid pace in line with the hyper-connected society of people-to-things and things-to-things network connections. International Data Corporation (IDC), a market research institute, estimates that the wearable-device industry will grow rapidly by 2020, despite not yet attracting a popular response. This study investigates the trend of the wearable-device industry and draws implications for product and service development through user experience analysis. The subject of analysis was smart bands and the data generated from product review were collected and analyzed. As a result, user experience could extract utility, usability, aesthetics, value, and reliability, and polarity was analysed and visualized in the extracted data. The study results reveal that current wearable-devices are expensive, that users cannot receive useful information from the long-term viewpoint since the analysis of accumulated data remains focused on functional development, and that they are recognized as a fashion item or an accessory. These factors hinder the continuous usage, motivation and market spread of the product. In a future follow-up study, we will conduct a comparative study on bands and watches by analyzing the second smart watch.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.280-280
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• 2007

$Pb(Zr,Ti)O_3$ (PZT) 강유전체 박막은 높은 잔류 분극 (remanent polarization) 특성 때문에 현재 강유전체 메모리 (FeRAM) 소자에 적용하기 위하여 가장 활발히 연구되고 있다. 그런데 PZT 물질은 피로 (fatigue) 및 임프린트 (imprint) 등의 장시간 신뢰성 (long-term reliability) 특성이 취약한 단점을 가지고 있다. 이러한 신뢰성 문제를 해결할 수 있는 효과적인 방법 중의 하나는 $IrO_2$, $SrRuO_3$(SRO) 등의 산화물 전극을 사용하는 것이다. 많은 산화물 전극 중에서 SRO는 PZT와 비슷한 pseudo-perovskite 결정구조를 갖고 격자 상수도 비슷하여, PZT 커패시터의 강유전 특성 및 신뢰성을 향상시키는데 매우 효과적인 것으로 알려져 있다. 따라서 본 연구는 PZT 커패시터에 적용하기 위하여 SRO 박막을 증착하고 이의 전기적 특성 및 미세구조를 분석하고자 하였다. 또 실제로 SRO 박막을 상부전극과 PZT 사이의 버퍼 층 (buffer layer)으로 적용한 경우의 커패시터 특성도 평가하였다. 먼저 다결정 SRO 박막을 $SiO_2$/Si 기판 위에 DC 마그네트론 스퍼터링 법 (DC magnetron sputtering method)으로 증착하였다. 그 다음 이러한 SRO 박막의 미세구조, 결정성 및 전기적 특성이 증착 조건들의 변화에 따라서 어떤 경향성을 보이는지를 평가하였다. 기판 온도는 $350\;{\sim}\;650^{\circ}C$ 범위에서 변화시켰고, 증착 파워는 500 ~ 800 W 범위에서 변화시켰다. 또 Ar+$O_2$ 혼합 가스에서 산소의 혼합 비율을 20 ~ 50% 범위에서 변화시켰다. 이러한 실험 결과 SRO 박막의 전기적 특성 및 미세 구조는 기판의 증착 온도에 따라서 가장 민감하게 변함을 관찰할 수 있었다. 다른 증착 조건과 무관하게 $450^{\circ}C$ 이상의 온도에서 증착된 SRO 박막은 모두 주상정 구조 (columnar structure)를 형성하며 (110) 방향성을 강하게 나타내었다. 가장 낮은 전기 저항은 $550^{\circ}C$ 증착 온도에서 얻을 수 있었는데, 그 값은 약 $440\;{\mu}{\Omega}{\cdot}cm$ 이었다. SRO 버퍼 충을 적용하여 제작한 PZT 커패시터의 잔류 분극 (Pr) 값은 약 $30\;{\mu}C/cm^2$ 정도로 매우 높은 값을 나타내었고, 피로 손실 (fatigue loss)도 $1{\times}10^{11}$ 스위칭 사이클 후에 약 11% 정도로 매우 양호한 값을 나타내었다.

• Journal of the Korean Institute of Gas
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• v.17 no.5
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• pp.64-68
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• 2013

Non destructive testing(NDT) methods of electrofusion(EF) joints of thermoplastics pipes are required for fusion joint safety and for the long term reliability of a pipe system. Electrofusion joints, which are joined at the proper fusion process and procedures, may encounter defects due to the difference of ovality between pipes and coupling, improper fusion process or porosity result from electrofusion joining. These defects can cause the failure of pipeline and by extension, they can be caused the limit to expand the use of plastics pipes. This paper studies inspection results using ultrasonic imaging method for damaged polyethylene electrofusion joints. Gas was leaking from 250mm diameter polyethylene electrofusion joints at February 2004 which was electrofused at December 1994 and operation pressure was 2.45kPa. First, surface inspection was conducted and then in order to find the types of defects examination using ultrasonic imaging method was performed. Lack of fusion and inappropriate inserting for polyethylene pipes into electrofusion coupling were found and causes of the gas leak were judged that misalignment and insert defect. Cutting inspection was performed and each inspection results were compared to. Results of ultrasonic imaging method and cutting inspection were the same.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3452-3459
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• 2012

The purpose of this study was to analyze the relationships on participation on health education program toward skin care and the improvement of healthy life habit. The subject of the study was selected by multi-stage stratified cluster random sampling among the skin care education center to learn health education program toward skin care among women in the Seoul and Kyunggi area. The data were collected through a questionnaire adapted from Payne and Hahn's(1986) 'Understanding Your Health-A personal profile; Evaluating Your Health'. The pilot test was executed after the questionnaire was translated into Korean. The statistics employed the study were validity and reliability test, $x^2$ verification, frequency, ANOVA, multiple classification analysis, ANCOVA and Multiple Regression Analysis. The results that were derived from these processes were as follows: First, before and after on health education program toward skin care, the student's healthy life habit is partially changed. Second, the relationship the period of education program and the characteristic healthy life habit, long-term skin care education is positively affected sleeping habit, anti-stress treatment, exercise and nutrition. Third, the relationship on the frequency of education program and the characteristic healthy life habit, more frequently participation on skin care education is positively affected on healthy life habit and exercise.

• Journal of Distribution Science
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• v.14 no.4
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• pp.93-101
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• 2016

Purpose - As more consumers pursue high quality products at reasonable prices, Korean retail companies are increasing investment in expanding their outlet stores. Despite the growing importance of the outlet business, there has been very little empirical research on consumers' outlet shopping behaviors. This study aimed to investigate the relationships between consumers' perceived product value (performance quality, value for money, and social value) of outlet stores and overall shopping satisfaction and the effect of shopping satisfaction on outlet store loyalty. Research design, data and methodology - The authors developed a structural model in which performance quality, value for money, and social value of products are proposed to affect overall outlet shopping satisfaction, thus increasing customer loyalty. To analyze the research model, data were collected from 88 shoppers at suburban outlets. SPSS 21.0 and AMOS 21.0 were utilized to test the hypotheses. The unidimensionality of each construct was supported from the results of the reliability test with Cronbach's α and confirmatory factor analyses. Correlation analysis was performed and the results warranted the nomological validity of the measures. The fit statistics of the overall model analysis demonstrated an acceptable fit(X²(₁₆₁)=171.651, p=.000; X²/df=1.546; GFI=.821, NFI=.879, TLI=.942, CFI=.953, RMR=.035, RMSEA=.079). Results - The findings are as follows. First, consumers' perceived value of product performance quality had a significant positive effect on overall outlet shopping satisfaction. Consumers, who evaluate performance quality of the product more positively, tend to express stronger satisfaction and happiness about outlet shopping experience. Second, consumers' perceived social value of outlet products influenced their overall satisfaction significantly. Consumers who believe that products of outlet stores enhance self-concepts are more likely to satisfy with outlet shopping experience. However, consumers' perception of outlet products on value for money was not found to significantly influence overall shopping satisfaction. Finally, overall shopping satisfaction had a significant and positive influence on loyalty. Conclusions - While outlet retailers have traditionally focused on promoting competitively priced merchandise, the results of this study suggest that customers' overall satisfaction with outlet shopping is influenced more by the non-price-related product values. In the context of an outlet shopping environment, performance quality and social value of the products were found to be more critical predictors of customer overall satisfaction. Therefore, it would not be efficient for outlet retailers to highlight economic value of their merchandise. Instead, they need to investigate the performance quality of the products regularly and try to deliver quality guaranteed goods to enhance customer satisfaction. Also, outlet retailers should differentiate their businesses by carrying more unique and prestigious brands and emphasize higher social value and symbolic meanings of their products. As competition among outlet retailers are getting fierce, retail companies need to focus on strengthening customer loyalty with a long-term perspective. With a deeper understanding of the relationship between consumers' perceived product values and shopping satisfaction, outlet retailers will be able to develop customer loyalty strategies effectively and to achieve competitive advantage.

• Korean Journal of Construction Engineering and Management
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• v.19 no.5
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• pp.61-69
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• 2018

Construction projects consist of long-term on-site production, and most disciplines are featured by outdoor works. Therefore, when a process plan is established, non-working days are calculated and reflected in a process schedule to comply with the planned construction period. However, necessary information and working methods are different in the course of the work, so the method of calculation varies depending on persons even for the same site, and the result is also very different. Therefore, scientific and quantitative understanding of business information is needed. This study reconstructed non-working day estimation process by collecting and organizing the information necessary for non-working day estimation, and designed the demonstration screen based on the reconstructed process and verified through expert interview at each stage. As a result, it showed about 69% reduction of work time and reliability of 92% work information matrix, and 80% of the experts evaluated the systemization of the relevant work. This study is expected to improve the understanding of work and increase the efficiency of work performance, and the study on systemization in the future should be continued.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.169-177
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• 2018

Glass fiber reinforced polyester (GFRP) composites are widely used as structural materials in harsh environment such as underground pipes, tanks and boat hulls, which requires long-term water resistance. Especially, these materials might be damaged due to delamination between gelcoat and composites through an osmotic process when they are immersed in water. In this study, GFRP laminates were prepared by surface treatment of UPE (unsaturated polyester) gelcoat by vacuum infusion process to improve the durability of composite materials used in underground pipes. The composite surface coated with gelcoat was examined for surface defects, cracking, and hardness change characteristics in water-immersion environments (different temperatures of $60^{\circ}C$, $75^{\circ}C$, and $85^{\circ}C$). The penetration depth of cracks was investigated by micro CT imaging according to water immersion temperature. It was confirmed that cracks developed into the composites material at $75^{\circ}C$ and $85^{\circ}C$ causing loss of durability of the materials. The point at which the initial crack initiated was defined as the failure time and the life expectancy at $23^{\circ}C$ was measured using the Arrhenius equation. The results from this study is expected to be applied to reliability evaluation of various industrial fields where gelcoat is applied such as civil engineering, construction, and marine industry.

• Journal of the Korean Society of Radiology
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• v.12 no.6
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• pp.785-791
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• 2018

Recently, Disk array is widely used as a long term storage device in PACS, but reliability is not enough in relation to annual failure rate of disk. Between October 2016 and February 2017, we scanned the serial port of the hard disk while reading or storing medical images on a PACS reader. The data rate was calculated from the data stored in HDD 99ea that were used in the PCAS image storage device and in HDD 101ea that were used in the Personal Computer. When a CT image was read from a PACS reader, Reading was 87.8% and Writing was 12.2% in units of several tens of megabytes or less. When the CT image was stored in the PACS reader, Reading was 11.4% and Writing was 88.6% in units of several tens of megabytes or less. While reading the excel file on the personal computer, Reading was 75% and Writing was 25% in less than 3 MB, and In the process of storing the excel file on the personal computer, Reading was carried out by 38% and Writing was carreid out 62% in the units of 3 MB or less. The transfer rate of the hard disk used in the PACS image storage device was 10 GB/h, and the transfer rate per hour of the hard disk of the personal computer was 5 GB / h. Annual failure rate of hard disk of image storage system is 0.97 ~ 1.13%, Annual failure rate of Hard Disk of personal computer is 0.97 ~ 1.13%. the higher transfer rate is, the higher annual failure rate is. These results will be used as a basis for predicting the life expectancy of the hard disk and the annual failure rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.488-494
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• 2019

Precision Guided Missiles after production and militarization have various characteristics that enable the final performance to be identified by conducting live-fire tests after long-term storage. Likewise, the performance and reliability of ${\bigcirc}{\bigcirc}$ Missiles, which are currently used by the Korean Navy, are also verified consistently by conducting live-fire tests after militarization. Specially, the live fire test at '00 year, which was conducted by Korean Navy, showed the result that 'Ring', which is a component of the canister's front cover, was jammed with wings for propulsion and then broke away from the canister during the missile launch process. This situation led to an interruption of the deployment of wings and finally affected the missile's flight performance. The results of a survey of the canisters of those missiles whose live fire tests were conducted successfully, based on the live fire test at '00 year, showed the 'Ring's separation from canisters. This raises recognition for the need to solve the problems of 'Ring's separation and breakaway. This study suggests an improvement derived by the result of live-fire tests and introduces the effect of final launch performance of ${\bigcirc}{\bigcirc}$ Missiles and test result after applying the improvement.

• Journal of radiological science and technology
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• v.44 no.4
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• pp.359-365
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• 2021

A heavy particle accelerator is a device that accelerates particles using high energy and is used in various fields such as medical and industrial fields as well as research. However, secondary neutrons and particle fragments are generated by the high-energy particle beam, and among them, the neutrons do not have an electric charge and directly interact with the nucleus to cause radiation of the material. Quantitative evaluation of the radioactive material produced in this way is necessary, but there are many difficulties in actual measurement during or after operation. Therefore, this study compared and evaluated the generated radioactive material in the concrete shield for protons and carbon ions of specific energy by using the simulation code FLUKA. For the evaluation of each energy of proton beam and carbon ion, the reliability of the source term was secured within 2% of the relative error with the data of the NASA Space Radiation Laboratory(NSRL), which is an internationally standardized data. In the evaluation, carbon ions exhibited higher neutron flux than protons. Afterwards, in the evaluation of radioactive materials under actual operating conditions for disposal, a large amount of short-lived beta-decay nuclides occurred immediately after the operation was terminated, and in the case of protons with a high beam speed, more radioactive products were generated than carbon ions. At this time, radionuclides of ⁴⁴Sc, ³H and ²²Na were observed at a high rate. In addition, as the cooling time elapsed, the ratio of long-lived nuclides increased. For nonparticulate radionuclides, ³H, ²²Na, and for particulate radionuclides, ⁴⁴Ti, ⁵⁵Fe, ⁶⁰Co, ¹⁵²Eu, and ¹⁵⁴Eu nuclides showed a high ratio. In this study, it is judged that it is possible to use the particle accelerator as basic data for facility maintenance, repair and dismantling through the prediction of radioactive materials in concrete according to the cooling time after operation and termination of operation.