• Journal of Biomedical Engineering Research
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• v.41 no.1
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• pp.8-13
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• 2020

To develop cardiovascular simulator capable of implementing pulse waves similar to the human body, accurate information about reflection wave is required. However, the conclusion is still not clear and various discussions are underway. In this study, the pulse wave velocity of the tube used in the experiment was first determined by measuring the pressure waves at two points in a single tube system with the experimental device to implement the pulse wave transmission of blood vessels, and the superposition time and characteristics of the reflection wave were confirmed. After that, an air chamber was set at the reflection site, and the effect of the change of air volume on the reflection wave was investigated. Finally, the effect of the number of branches connected to a single tube on the reflection wave was investigated. The superposition time of the reflection wave can be controlled by the air volume of the air chamber, and the magnitude of the reflection wave is influenced by the number of reflection sites that generate the reflection wave. The results of this study may be of practical assistance to simulator researchers who want to implement pulse wave similar to clinical data. It is expected that the more results similar to clinical are provided, the greater the scope of the simulator's contribution to clinical cardiovascular research.

• Journal of Korean Academy of Nursing Administration
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• v.19 no.2
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• pp.282-291
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• 2013

Purpose: The purpose of this study was to identify clusters of nursing competency, and investigate the influence of reflective thinking, team learning climate, and learning organization building according to nursing competency clusters. Methods: Participants were 244 clinical nurses who worked in 4 general hospitals in Gwangju Metropolitan City. Data were collected by self-report questionnaires during June and July, 2011. Nursing competency, levels of reflection hierarchy, team learning climate, and learning organization building were measured. Data were analyzed using frequencies, means, t-test, one-way ANOVA, Pearson correlation coefficients, and K-means cluster analysis with SPSS/WIN 20.0 version. Results: Nursing competency correlated positively with intensive reflection, reflection, team learning climate, and learning organization building (p<.001). There were three clusters of nursing competency in a clinical ladder, which were derived from cluster analysis, grouped as high, middle, and low competency. Intensive reflection, reflection, team learning climate, and learning organization building showed significant differences according to grouping of nursing competency. Conclusion: The results indicate that developing intensive reflection, reflection, team learning climate, and learning organization building would be useful strategies for enhancement of nursing competency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.127-127
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• 2009

The most important part of the fabrication solar cells is the anti-reflection coating when excludes the kinds of silicon substrates (crystalline, polycrystalline, or amorphous), patterns and materials of electrodes. Anti-reflection coatings reduce the reflection of sunlight and at last increase the intensity of radiation to inside of solar cells. So, we can obtain increase of solar cell efficiency about 10% using anti-reflection coating. There are many kinds of anti-reflection film for solar cell, such as SiN, $SiO_2$, a-Si, and so on. And, they have two functions, anti-reflection and passivation. However such materials could not perfectly prevent reflection. So, in this work, we investigated the anti-reflection coating with the columnar structure ZnO thin film. We synthesized columnar structure ZnO film on glass substrates. The ZnO films were synthesized using a RF magnetron sputtering system with a pure (99.95%) ZnO target at room temperature. The anti-reflection coating layer was sputtered by argon and oxygen gases. The angle of target and substrate measures 0, 20, 40, 60 degrees, the working pressure 10 mtorr and the 250 W of RF power during 40 minutes. The confirm the growth mechanism of ZnO on columnar structure, the anti-reflection coating layer was observed by field emission scanning electron microscopy (FE-SEM). The optical trends were observed by UV-vis and Elleso meter.

• Journal of the Korea Computer Graphics Society
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• v.20 no.1
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• pp.13-19
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• 2014

In this paper, we introduce a real-time method to render a 3D scene using image-based lighting. Previous approaches for image-based lighting focused on diffuse reflection and mirror-like specular reflection. In this paper, we provide a simple preprocessing approach to efficiently approximate Phong reflection model, which has been used for computer graphics applications for several decades. For diffuse reflection, we generate a texture map for diffuse reflection by integrating the source image in preprocessing step, similarly to the previous approaches. We adopt the similar idea to produce a set of specular reflection maps for various material shininess. By doing this, we can render a dynamic scene without high computational complexity or numerous texture map access.

• Journal of Korean Elementary Science Education
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• v.31 no.3
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• pp.372-385
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• 2012

For decades, reflection has been recognised as a meaningful tool to bring forth teachers' ownership as well as knowledge and action empowerment in teacher education. Yet there have been few studies on elementary teachers' reflection on their science teaching in Korea. In this study, 71 reflective journals of 24 elementary teachers on their science teaching were analyzed. The characteristics of reflective journals were analyzed in terms of 'productive reflection', a concept suggested by Davis (2006). Unproductive reflection is mainly descriptive without analysis, whereas productive reflection can promote teachers' learning by integrating four aspects of teaching (learner/learning, subject matter knowledge, instruction and assessment). The result showed what elementary teachers consider and emphasize and how they integrate their ideas. Most of reflective journals included aspects of 'instruction', 'learner/learning', and 'subject matter knowledge'. However 'instruction' was emphasized most frequently (69.0%) than 'subject matter knowledge' (33.8%) and 'learner/learning' (26.8%). 'Assessment' was hardly included nor emphasized. More than half of the journals (56.3%) showed no integrations, which were unproductive reflection. A third of the journals (32.4%) integrated only two aspects among four. Average score of integrations was 1.6 on a scale of 4 points. The integrations were not affected by the length of reflective journals and the teaching experience. These findings suggest that productive reflection would not increase naturally with teaching experience and there needs more tactful guidance to develop elementary teachers' productive reflection on their science teaching.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.105-111
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• 2023

The purpose of this study is to find out what self-reflection, relationship reflection, gratitude and happiness reflection, and social reflection among the sayings of Confucius in the Analects of Confucius are reinterpreted in various ways depending on the times and what meaning they contain today. Self-reflection is the process of considering one's identity, values, emotions, thoughts, and actions. Humans grow through reflection because they can identify their own problems, acknowledge their mistakes, find opportunities for improvement, and set a direction for the future. Confucius pursued the life of a gentleman as a person who constantly reflects on his life and grows. We classified it into the four categories presented above and examined them. In an era of coexistence with generative AI, Confucius' reflective life and teachings are recognized as important values in modern society in terms of human-centered value orientation, mature human relationships, and continuous social value realization, and reflection on happiness is the best attitude to life.

• The Journal of the Acoustical Society of Korea
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• v.28 no.3
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• pp.174-186
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• 2009

When we apply a propagation model to the ocean with boundaries, we can calculate reflected wave using reflection coefficient suggested by Rayleigh assuming the boundaries are flat. But boundaries in ocean such as sea surface and sea bottom have an irregular rough surface. To calculate the reflection loss for an irregular boundary, it is needed to compute the coherent reflection coefficient based on an experimental formula or scattering theory. In this article, we derive the coherent reflection coefficients for a fluid-fluid interface using perturbation theory, Kirchhoff approximation and small-slope approximation respectively. Based on each formula, we can calculate coherent reflection coefficients for a rough sea surface or sea bottom, and then compare them to the Rayleigh reflection coefficient to analyze the reflection loss for a random rough surface. In general, the coherent reflection coefficient based on small-slope approximation has a wide valid region. Comparing it with the coherent reflection coefficients derived from the Kirchhoff approximation and perturbation theory, we discuss a valid region of them.

• Journal of Engineering Education Research
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• v.16 no.3
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• pp.42-50
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• 2013

The main purpose of this study was to develop a program outcomes assessment tool using reflection journal. Reflection journal has recently come to gain more attention from school as an alternative assessment tool. Although numerous studies reconfirmed the educational importance and value of reflection journal as an assessment tool, research on the assessment tool of the engineering accreditation, based on education view is scarce. After literature reviews about the case studies on the program outcomes assessment, this study, to analyse the current assessment tools, and then, examined the educational implications of reflection journal as a program outcomes assessment tool. This study suggested the assessment tool using reflection journal for PO6 (teamwork) and PO11 (engineering ethics), one of the most important assessment items in engineering accreditation. In this study, we used the performance criteria, assessment criteria, rubric, and closed the loop to measure the teamwork and engineering ethics. The result of this study is significant in terms of guiding the future evaluation system development for program outcomes.

• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.856-862
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• 2020

Defect inspection system for industrial applications takes the important portion. Non-destructive inspection method has been significantly improved. Infrared thermography, as one of method for non-destructive inspection, can provide relatively precise data and quick inspection time. This study, it was performed to measure defect according to the measurement limit of the non-visible areas such as the back surface of the pipe using reflection plate using reflection plate based on Infrared thermography. The materials of the reflection plate were determined in consideration of the space limitation and the thermal characteristics, and defects were detected by the manufactured reflection plate. Detection of defect in non-visible area using the candidate materials for reflection plate was conducted.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.19 no.1
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• pp.47-54
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• 2015

Objective Wave reflection is an important factor that determines the shape of the pulse wave. The purpose of this study is to compare the conventional method used for estimating the reflection site of pulse with a cardiovascular simulator. Methods: In this study, cardiovascular simulator with one elastic tube was used. The pressure and flow was measured simultaneously at three different points. The measured data were used to the conventional methods to estimate the pulse wave reflection site. The results were compared with the known length which were the distances from the measured points to the end of tube. Results & Conclusions: There is a significant error with the time domain method. While, the reflection site with the frequency domain method was similar to the actual reflection site.