• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.55-55
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• 2015

Today, engineers are facing new set of challenges that are quite different from the conventional ones. Information technologies are rapidly commoditizing while the paths beyond the current roadmaps became uncertain as various technologies have been pushed to their limits. Along with these changes in IT ecosystems, grand challenges such as global security, health, sustainability, and energy increasingly require trans-disciplinary solutions that go beyond the traditional arenas in STEM (Science, Technology, Engineering and Mathematics). Addressing these needs is shifting engineering education and research to a new paradigm where the emphasis is placed on the consilience for holistic and system level understanding and the convergence of technology with AHSD (arts, humanities, social science, and design). At the center of this evolutionary convergence, nanotechnologies are enabling novel functionalities such as bio-compatibility, flexibility, low power, and sustainability while on a mission to meet scalability and low cost for smart electronics, u-health, sensing networks, and self-sustainable energy systems. This talk introduces the efforts of convergence based on the emerging nano technology tool sets in the newly launched School of Integrated Technology and the Yonsei Institute of Convergence Technology at Yonsei International Campus. While the conventional devices have largely depended upon the inherent material properties, the newer devices are enabled by nanoscale dimensions and structures in increasingly standardized and scalable fabrication platform. Localized surface plasmon resonance in 0 dimensional nano particles and structures leads to subwavelength confinement and enhanced near-field interactions enabling novel field of metal photonics for sensing and integrated photonic applications [1,2]. Unique properties offered by 1 dimensional nanowires and 2 dimensional materials and structures can enable novel electronic, photonic, nano-bio, and biomimetic applications [3-5]. These novel functionalities offered by the emerging nanotechnologies are continuously finding pathways to be part of smart systems to improve the overall quality of life.

• Journal of Korean Dental Science
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• v.12 no.2
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• pp.58-65
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• 2019

Purpose: This study was aimed to investigate the possibility of utilizing smart device-based test (SBT) for competency evaluation in dental education and to analyze the student responses on overall competency evaluation using SBT method, in comparison to ubiquitous-based test (UBT). Materials and Methods: Questionnaire surveys have been conducted at Yonsei University College of Dentistry from 2015 to 2018 to obtain students' feedback on the application of SBT to competency evaluation. In addition, in order to supplement the competency evaluation procedure, considerations were explored by comparing the expected and actual difficulty of each item when preparing items for competency evaluation with SBT. Result: According to the survey results, student responses between the initial two years (2015 and 2016) differed from those in next two years (2017 and 2018). Students in 2017 and 2018 had more positive responses on competency evaluation with SBT. To determine the test validity, criterion-referenced evaluation was adopted to compare the data in 2017 and 2018 and slight differences in test difficulty in 2018 between the expected and actual difficulty of items were found. Conclusion: The results indicated that SBT was more appropriate for competency evaluation than UBT, based on four-year period of competency evaluation. The SBT was not affected by either the file size or the number of test-takers. Interestingly, students were not sensitive to test version of competency evaluation (paper-based test and SBT). This study suggests that the quality of the test items should be measured by continuous monitoring of the expected and actual difficulty of items for determining test validity. More detailed results and discussions of the findings are given for the development of test procedure and further potential research directions in dental education.

• Nutrition Research and Practice
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• v.8 no.5
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• pp.544-549
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• 2014

BACKGROUND/OBJECTIVES: Obesity-associated insulin resistance is a strong risk factor for type 2 diabetes mellitus. The aim of this study was to investigate the effect of myricetin on adiposity, insulin resistance, and inflammatory markers in mice with diet-induced insulin resistance. MATERIALS/METHODS: Five-week-old male C57BL/6J mice were fed a basal diet, a high-fat, high-sucrose (HFHS) diet, or the HFHS diet containing 0.06% myricetin or 0.12% myricetin for 12 weeks after a 1-week adaptation, and body weight and food intake were monitored. After sacrifice, serum lipid profiles, glucose, insulin, adipocyte-derived hormones, and proinflammatory cytokines were measured. The homeostasis model assessment for insulin resistance (HOMA-IR) was determined. RESULTS: Myricetin given at 0.12% of the total diet significantly reduced body weight, weight gain, and epidydimal white adipose tissue weight, and improved hypertriglyceridemia and hypercholesterolemia without a significant influence on food intake in mice fed the HFHS diet. Serum glucose and insulin levels, as well as HOMA-IR values, decreased significantly by 0.12% myricetin supplementation in mice fed the HFHS diet. Myricetin given at 0.12% of the total diet significantly reduced serum levels of leptin, tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and interleukin-6 (IL-6) in mice fed the HFHS diet. CONCLUSIONS: These findings suggest that myricetin may have a protective effect against diet-induced obesity and insulin resistance in mice fed HFHS diet, and that alleviation of insulin resistance could partly occur by improving obesity and reducing serum proinflammatory cytokine levels.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.206-214
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• 2017

In this study, measurement of thermophysical properties of materials at high temperatures was performed. This experiment employed a heater device to heat the material to a high temperature. The images of the specimen surface due to thermal load at various temperatures were recorded using charge-coupled device (CCD) cameras. Afterwards, the full-field thermal deformation of the specimen was determined using the digital image correlation (DIC) method. The capability and accuracy of the proposed technique are verified by two experiments: (1) thermal deformation and strain measurement of a stainless steel specimen that was heated to $590^{\circ}C$ and (2) thermal expansion and thermal contraction measurements of specimen in the process of heating and cooling. This research focused on two goals: first, obtaining the temperature dependence of the coefficient of thermal expansion, which can be used as data input for finite element simulation; and second, investigating the capability of the DIC method in measuring full-field thermal deformation and strain. The results of the measured coefficient of thermal expansion were close to the values available in the handbook. The measurement results were in good agreement with finite element method simulation results. The results reveal that DIC is an effective and accurate technique for measuring full-field high-temperature thermal strain in engineering fields such as aerospace engineering.

• Nutrition Research and Practice
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• v.8 no.2
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• pp.172-176
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• 2014

BACKGROUND/OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) is becoming an important public health problem as metabolic syndrome and type 2 diabetes have become epidemic. In this study we investigated the protective effect of Cordyceps militaris (C. militaris) against NAFLD in an obese mouse model. MATERIALS/METHODS: Four-week-old male ob/ob mice were fed an AIN-93G diet or a diet containing 1% C. militaris water extract for 10 weeks after 1 week of adaptation. Serum glucose, insulin, free fatty acid (FFA), alanine transaminase (ALT), and proinflammatory cytokines were measured. Hepatic levels of lipids, glutathione (GSH), and lipid peroxide were determined. RESULTS: Consumption of C. militaris significantly decreased serum glucose, as well as homeostasis model assessment for insulin resistance (HOMA-IR), in ob/ob mice. In addition to lowering serum FFA levels, C. militaris also significantly decreased hepatic total lipids and triglyceride contents. Serum ALT activities and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and interleukin-6 (IL-6) levels were reduced by C. militaris. Consumption of C. militaris increased hepatic GSH and reduced lipid peroxide levels. CONCLUSIONS: These results indicate that C. militaris can exert protective effects against development of NAFLD, partly by reducing inflammatory cytokines and improving hepatic antioxidant status in ob/ob mice.

• Journal of Internet of Things and Convergence
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• v.5 no.2
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• pp.73-79
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• 2019

Research is underway on services and systems that provide real-time alerts for suffocating gases and potentially explosive materials, but currently smart bend type services are lacking. This study supports real-time identification of explosion hazards due to static electricity in the workplace and immediate elimination of accident occurrence factors, real-time monitoring of worker status and workplace hazards (oxygen, hazardous chemical concentration), and immediate warning and data in case of danger. We propose a method of establishing an accident prevention system through analysis. In this way, various accidents that may occur in industrial sites are monitored using IoT-based intelligent sensor nodes, wireless network technology, data processing middleware, and integrated control system, and real-time risk information at the industrial sites is prevented and accidents are prevented. By supporting a safe working environment, the company can significantly reduce costs compared to post-procurement costs.

• The Journal of Advanced Prosthodontics
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• v.6 no.2
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• pp.88-95
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• 2014

PURPOSE. The purpose of this study is to evaluate if pre-treatment with desensitizers have a negative effect on microtensile bond strength before cementing a restoration using recently introduced self-adhesive resin cement to dentin. MATERIALS AND METHODS. Thirty-five human molars' occlusal surfaces were ground to expose dentin; and were randomly grouped as (n=5); 1) Gluma-(Glutaraldehyde/HEMA) 2) Aqua-Prep F-(Fluoride), 3) Bisblock-(Oxalate), 4) Cervitec Plus-(Clorhexidine), 5) Smart protect-(Triclosan), 6) Nd:YAG laser, 7) No treatment (control). After applying the selected agent, RelyX U200 self-adhesive resin cement was used to bond composite resin blocks to dentin. All groups were subjected to thermocycling for 1000 cycles between $5-55^{\circ}C$. Each bonded specimen was sectioned to microbars ($6mm{\times}1mm{\times}1mm$) (n=20). Specimens were submitted to microtensile bond strength test at a crosshead speed of 0.5 mm/min. Kolmogorov-Smirnov, Levene's test, Kruskal-Wallis One-way Analysis of Variance, and Conover's nonparametric statistical analysis were used (P<.05). RESULTS. Gluma, Smart Protect and Nd:YAG laser treatments showed comparable microtensile bond strengths compared with the control group (P>.05). The microtensile bond strengths of Aqua-Prep F, and Cervitec Plus were similar to each other but significantly lower than the control group (P<.05). Bisblock showed the lowest microtensile bond strength among all groups (P<.001). Most groups showed adhesive failure. CONCLUSION. Within the limitation of this study, it is not recommended to use Aqua-prep F, Cervitec Plus and Bisblock on dentin when used with a self-adhesive resin cement due to the decrease they cause in bond strength. Beside, pre-treatment of dentin with Gluma, Smart protect, and Nd:YAG laser do not have a negative effect.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.2
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• pp.81-85
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• 2017

Fiber-reinforced polymer composites, which are made by combining a continuous fiber that acts as reinforcement and a homogeneous polymeric material that acts as a host, are engineering materials with high strength and stiffness and a lightweight structure. In this study, a shape memory alloy(SMA) reinforced composite actuator is presented. This actuator is used to generate large deformations in single lightweight structures and can be used in applications requiring a high degree of adaptability to various external conditions. The proposed actuator consists of numerous individual laminas of the glass-fiber fabric that are embedded in a polymeric matrix. To characterize its deformation behavior, the composition of the actuator was changed by changing the matrix material and the number of the glass-fiber fabric layers. In addition, current of various magnitudes were applied to each actuator to study the effect of the heating of SMA wires on applying current.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.638-641
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• 2013

In college, you can view the online quiz through the cyber education, and online learning. However, if there is no computer has a problem that can not be many students it is in place or not the Internet watch online quizzes. In recent years, many college students have a smart phone, from anywhere, using smartphone, you have utilized various Web surfing, news, and Messenger. In addition, office workers and students, have to learn to put to PDF necessary materials through the smartphone. Advantage of smart phones, have a feature that can be easy to carry and use anywhere at any time. Online learning from anywhere via a smart phone, so that you can see the online quizzes, in this paper, the system that not only online quizzes through a smartphone using the Hybrid-App, you can see in real time the results and scores of the person I proposed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.533-539
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• 2013

Recently, Ionic Polymer Metal Composite (IPMC) systems receive great attention in the fields of the medical and biomedical Engineering because of several merits in terms of new actuators and sensors and fuel cell materials. When the voltage is excited to IPMC system, it moves. Conversely, if there are any movement on the IPMC, the IPMC has charge voltage by the internal properties. Therefore the IPMC can be used as a motion sensor or force sensor. In this paper, we identify characteristics of the IPMC and control its movements from remote locations by the smart-phone system based on visual information for monitoring. Additionally, control of movements of the IPMC is realized by transmit motion commands using the smart-phone system with the blue-tooth communication. Unfortunately, there are some deficiencies to perfectly attain physical properties of the IPMC systems from our experiments in this paper. However, in its utilization point of view, we demonstrate that the IPMC has some potentials as new sensors, actuators, and fuel cells.