• Journal of Cardiovascular Imaging
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• v.31 no.3
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• pp.135-141
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• 2023

BACKGROUND: Global longitudinal strain (GLS) is an accurate and reproducible parameter of left ventricular (LV) systolic function which has shown meaningful prognostic value. Fast, user-friendly, and accurate tools are required for its widespread implementation. We aim to compare a novel web-based tool with two established algorithms for strain analysis and test its reproducibility. METHODS: Thirty echocardiographic datasets with focused LV acquisitions were analyzed using three different semi-automated endocardial GLS algorithms by two readers. Analyses were repeated by one reader for the purpose of intra-observer variability. CAAS Qardia (Pie Medical Imaging) was compared with 2DCPA and AutoLV (TomTec). RESULTS: Mean GLS values were -15.0 ± 3.5% from Qardia, -15.3 ± 4.0% from 2DCPA, and -15.2 ± 3.8% from AutoLV. Mean GLS between Qardia and 2DCPA were not statistically different (p = 0.359), with a bias of -0.3%, limits of agreement (LOA) of 3.7%, and an intraclass correlation coefficient (ICC) of 0.88. Mean GLS between Qardia and AutoLV were not statistically different (p = 0.637), with a bias of -0.2%, LOA of 3.4%, and an ICC of 0.89. The coefficient of variation (CV) for intra-observer variability was 4.4% for Qardia, 8.4% 2DCPA, and 7.7% AutoLV. The CV for inter-observer variability was 4.5%, 8.1%, and 8.0%, respectively. CONCLUSIONS: In echocardiographic datasets of good image quality analyzed at an independent core laboratory using a standardized annotation method, a novel web-based tool for GLS analysis showed consistent results when compared with two algorithms of an established platform. Moreover, inter- and intra-observer reproducibility results were excellent.

• Bulletin of the Korean Chemical Society
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• v.25 no.8
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• pp.1273-1276
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• 2004

• Atmosphere
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• v.25 no.2
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• pp.235-248
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• 2015

In this study, we analyzed the three dimensional variations (latitude, longitude, and height of Jet core) and wind speed of upper Jet stream in the East Asian region using recent 35 years (1979~2013) of four reanalysis data (NCEP-R2, MERRA, ERA-Interim. and JRA-55). Most of Jet core is located in $30.0{\sim}37.5^{\circ}N$ and $13.0{\sim}157.5^{\circ}E$ although there are slight differences among the four reanalysis data. The wind speed differences among reanalysis are about $3m\;s^{-1}$ regardless of seasons, the weakest in NCEP-R2 and the strongest in JRA-55. Although significance level is not high, most of reanalysis showed that the Jet core has a tendency of southward moving during spring and winter, but moving northward during summer and fall. This amplified seasonal variation of Jet core suggests that seasonal variations of weather/climate can be increased in the East Asian region. The longitude of Jet core has a tendency of systematically westward moving and decreasing of zonal variations regardless of averaging methods and reanalysis data. In general, the Jet core shows a tendency of moving south-west-ward and upward, getting intensified during spring and winter regardless of the reanalysis data. However, the Jet core shows a tendency of moving westward and downward, and getting weakened during summer. In fall, there were no distinctive trends not only in wind speed but also three dimensional locations compared to other seasons. Although the significance levels are not high and variation patterns are slightly different according to the reanalysis data, our findings are more or less different from the previous results. So, more works are needed to clarify the three dimensional variation patterns of Jet core over the East Asian region as a result of global warming.

• Nuclear Engineering and Technology
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• v.45 no.6
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• pp.721-730
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• 2013

Within the framework of the ASTRID project, core design studies are being conducted by the CEA with support from AREVA and EDF. The pre-conceptual design studies are being conducted in accordance with the GEN IV reactor objectives, particularly in terms of improving safety. This involves limiting the consequences of 1) a hypothetical control rod withdrawal accident (by minimizing the core reactivity loss during the irradiation cycle), and 2) an hypothetical loss-of-flow accident (by reducing the sodium void worth). Two types of cores are being studied for the ASTRID project. The first is based on a 'large pin/small spacing wire' concept derived from the SFR V2b, while the other is based on an innovative CFV design. A distinctive feature of the CFV core is its negative sodium void worth. In 2011, the evaluation of a preliminary version (v1) of this CFV core for ASTRID underlined its potential capacity to improve the prevention of severe accidents. An improved version of the ASTRID CFV core (v2) was proposed in 2012 to comply with all the control rod withdrawal criteria, while increasing safety margins for all unprotected-loss-of-flow (ULOF) transients and improving the general design. This paper describes the CFV v2 design options and reports on the progress of the studies at the end of pre-conceptual design phase 1 concerning: - Core performance, - Intrinsic behavior during unprotected transients, - Simulation of severe accident scenarios, - Qualification requirements. The paper also specifies the open options for the materials, sub-assemblies, absorbers, and core monitoring that will continue to be studied during the conceptual design phase.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.464-469
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• 2017

This study evaluated the displacements of a Cu bar in the Y-direction and the relationship between swaging pressures and total contact forces to increase the productivity of the rotor core swaging process. Elastic-plastic numerical analyses of four different Cu bar shapes were performed with a constant swaging pressure to evaluate the displacements of the Cu bar in the Y-direction and the contact force distributions at the contact surfaces during the swaging process. Based on the numerical analysis results, the following conclusions were obtained. First, a simplified 2-dimensional cyclic symmetric analysis model was developed for the numerical analysis of the rotor core swaging process. Second, the final displacements of the Cu bar in the Y-direction were nearly the same as the change of the Cu bar size at a constant swaging pressure. Third, a linear relationship between the swaging pressures and the total contact forces, the so called resistance forces, was suggested.

• Design & Manufacturing
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• v.9 no.2
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• pp.34-37
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• 2015

The HEV Traction Motor Core manufacturing technology is a core component of HEV Traction Motor Core (Iron Core) is a key technology for the manufacture of eco-friendly automotive industry is essential for the competitiveness of the country must obtain the technology. In this study, the HEV Motor Core of the Rotor manufacturing technology, the Stator manufacturing technology applied to Press Lamination Die and Core(Iron Core) was developed and the results are discussed.

• East Asian mathematical journal
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• v.35 no.2
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• pp.163-172
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• 2019

In recent years, the term core literacy has been popular in educational circles all over the world, and there are more and more research on core literacy. At the same time, the mathematical culture has also been highly valued on a global scale. The mathematical culture is a part of college students' cultural quality, and then, what is the connection between the mathematical culture and mathematical core literacy? How to improve the mathematical core literacy of contemporary college students? This paper gives the corresponding answers to these two questions. By illustrating the concrete implementation of the course "Mathematical Culture" offered by Yanbian University, this paper discusses various measures for cultivating students' core qualities in Chinese universities. It must be useful and promote the research on mathematical core literacy for the educators in various countries.

• Journal of Sensor Science and Technology
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• v.27 no.2
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• pp.76-81
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• 2018

Au@ZnO core-shell nanoparticles (NPs) were prepared by a simple method followed by heat-treatment for gas sensor applications. The advantage of the core-shell morphology was investigated by comparing the gas sensing performances of Au@ZnO core-shell NPs with pure ZnO NPs and different wt% of Au-loaded ZnO NPs. The crystal structures, shapes, sizes, and morphologies of all sensing materials were characterized by XRD, TEM, and HAADF-STEM. Au@ZnO core-shell NPs were nearly spherical in shape and Au NPs were encapsulated in the center with a 40-45 nm ZnO shell outside. The gas sensing operating temperature for Au@ZnO core-shell NPs was $300^{\circ}C$, whereas it was $350^{\circ}C$ for pure ZnO NPs and Au-loaded ZnO NPs. The maximum response of Au@ZnO core-shell NPs to 1000 ppm CO at $300^{\circ}C$ was 77.3, which was three-fold higher than that of 2 wt% Au-loaded ZnO NPs. Electronic and chemical effects were the primary reasons for the improved sensitivity of Au@ZnO core-shell NPs. It was confirmed that Au@ZnO core-shell NPs had better sensitivity and stability than Au-loaded ZnO NPs.

• Journal of Korean Critical Care Nursing
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• v.9 no.2
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• pp.36-47
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• 2016

Purpose: The study examined core job characteristics and job preference to explain work performance among critical care nurses. The theoretical model was constructed based on the job characteristics model with core job characteristics as exogenous variables, and work performance and job preference as endogenous variables. Methods: A total of 228 hospital nurses participated in the study from May to September, 2015. Data were collected through structured questionnaires and analyzed using structural equation modeling. Results: The model showed a good fit to the data with $x^2/df=2.90$, goodness of fit index = .91, root mean square residual = .20, comparative fit index = .93, and incremental fit index = .93. The core job characteristics explained 64% of the variance in job preference. The core job characteristics and job preference explained 52% of the variance in work performance. Conclusions: The core job characteristics can explain the work performance among critical care nurses through job preference. Effective strategies to improve the work performance among critical care nurses should focus on the application of the core job characteristic into a productive work environment. Further studies are warranted to explore the role of job preference of critical care nurses in promoting their work performance.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.507-510
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• 2004

동중국해 북부에서 쿠로시오의 경계역으로 확장된 중국대륙 연안수가 주변의 북상 난류역에 의해 포획된 후 고립되는 현상이 1999년 및 2003년 NOAA 위성영상에 포착되었다. 1999년의 경우 cold core eddy는 약 2개월간 존재(5월초～6월 하순)하였고, cold core의 중심 수온은 15～20℃로 주변해역의 17～23℃보다 2～3℃ 낮게 나타났다. 1999년 5월 7일 획득된 SeaWiFS 위성자료로부터 추정된 클로로필 α 분포는 1999년 5월 6일부터 획득된 NOAA 위성수온 영상에 나타난 cold core eddy의 주변 가장자리 해역에서 비교적 높게 나타났다. 2003년 경우 2월 중순에 cold core의 수온은 9～10℃c였으며 직경 150km 정도였다. cold core의 수평규모는 50m 등수심 분포와 유사하게 나타났다. 이어도를 중심으로 동계 및 춘계에 나타나는 cold core eddy의 형성 메카니즘은 중국대륙 연안수와 쿠로시오 난류가 만나는 경계역에서의 힘의 균형과 계절풍 조건, 해저 지형 분포와 밀접한 관계성이 있는 것으로 사료된다.