• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.875-888
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• 2013

The researches have recently progressed toward the use of the superelastic shape memory alloys (SMAs) to develop new smart control systems that reduce permanent deformation occurring due to severe earthquake events and that automatically recover original configuration. The superelastic SMA materials are unique metallic alloys that can return to undeformed shape without additional heat treatments only after the removal of applied loads. Once the superelastic SMA materials are thus installed at the place where large deformations are likely to intensively occur, the structural system can make the best use of recentering capabilities. Therefore, this study is intended to propose new buckling-restrained braced frames (BRBFs) with superelastic SMA bracing systems. In order to verify the performance of such bracing systems, 6-story braced frame buildings were designed in accordance with the current design specifications and then nonlinear dynamic analyses were performed at 2D frame model by using seismic hazard ground motions. Based on the analysis results, BRBFs with innovative SMA bracing systems are compared to those with conventional steel bracing systems in terms of peak and residual inter-story drifts. Finally, the analysis results show that new SMA bracing systems are very effective to reduce the residual inter-story drifts.

• Resources Recycling
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• v.27 no.3
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• pp.16-29
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• 2018

In this study, metal and nonmetal contents and their economic values in ICT devices such as smart phones and laptop computers were evaluated. The electronic devices made by LG and Samsung were disassembled into 5 parts, which are printed circuit board assembly, battery, display, case and other electronic components. Metal and nonmetal contents in these parts were analyzed, and their economic values were calculated via multiplying the materials' contents by metal price obtained from KOMIS or nonmetal exchange price acquired from Korean recycling markets. Finally, the materials' contents and values according to each electronic parts and electronic devices were calculated. The results showed that the value of the smartphones and laptop computers of LG are 4,449.6 KRW (28,506 KRW/kg) and 6,830.2 KRW (7,053 KRW/kg), and those of Samsung are 1,849.3 KRW (13,499 KRW/kg) and 6,667.5 KRW (4,831 KRW/kg), respectively. It was also found that most of the value was concentrated in batteries and printed circuit board assemblies. In addition, Co, Au and Cu were found to be the most valuable resources in the devices.

• Journal of Distribution Science
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• v.14 no.6
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• pp.53-63
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• 2016

Purpose - This study examines the effects of the influence strategies on sales representative and headquarter trust, and investigates how sales representative trust plays a mediating role in the relationship between influence strategies and headquarter trust. For these purposes, a structural model which consists of several constructs was developed. In this model, influence strategies that consist of relational influence strategies (information exchange, recommend, promise) and mandatory influence strategies (legal plea, request, threat) were proposed to affect the sales representative trust and in turn, increase the headquarter trust. Thus, this study proposed that sale representative trust plays a core mediating role in the relationship between relational and mandatory influence strategies and headquarter trust in B2B food materials distribution context. Research design, data, and methodology - For these purposes, the authors collected the data from 208 B2B specialized complex agents. We used the 2,200 B2B specialized complex agents which trade with CJ, Ottogi, and Daesang firms and supply food materials to restaurant, school cafeteria, supermarket and traditional market as a sample frame. Once we identified 330 B2B specialized complex agent owners, CEOs, and/or Directors who had agreed to participate in this study, we dropped off a questionnaire at each B2B specialized complex agent and explained the purpose of this study. The survey was conducted from October 1, 2015 to December 15, 2015. A total of 230 questionnaires were collected. Of these collected questionnaires, 28 questionnaires excluded since they had not been fully completed. The data were analyzed using frequency test, reliability test, measurement model analysis, and structural equation modeling with SPSS and SmartPLS 2. Results - First, information exchange, recommendation, and promise of relational influence strategies had positive effects on sales representative trust. The threat of mandatory influence strategies had a negative effect on sales representative trust, but legal plea and request did not have a significant effect on sales representative trust. Second, information exchange and recommendation of relational influence strategies had positive effects on headquarter trust, but promise did not. Also, legal plea, request, and threat of mandatory influence strategies did not have a significant effect on headquarter trust. Third, this findings show that sales representative trust plays a partial mediator between information exchange and headquarter trust, and threat and headquarter trust, and a full mediator between promise and headquarter trust, and recommendation and headquarter trust. Conclusions - The aim of this study was to examine the effects how diverse dimensions of relational and mandatory influence strategies relate to sales representative trust and headquarter trust. To do so, we integrated the influence strategies and the trust transfer theory to hypothesize that various influence strategies increase sales representative and headquarter trust. The findings of this study suggest that headquarter firms should establish and enforce proper influence strategies guidelines to make clear what proper actions sales representatives should implement in relationship with B2B specialized complex agents. Also, relational and mandatory influence strategies must be regarded as a long-term and ongoing strategy that eventually build a long-term orientation with B2B specialized complex agents and guarantee a company's sustainable growth and success.

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.739-751
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• 2018

The purpose of this study is to identify the differences of argumentation discourses for Socio-Scientific Issues in the types of decision-making and personality traits of pre-service biology teachers. For this study, SSI discussion topics were selected according to four types of decision making: logical reasoning, suggestion of complement, emotional base, and internal conflict. Three groups were constructed based on personality traits such as extroversion, acceptability, and integrity. Each three group used the workbook specially developed and freely used the smart device for discussion. A recorder and a camcorder were used to record each group, their behavior was recorded and the written materials during the discussion were collected for the results. Using Walton's analysis framework, the collected data analyzed in terms of the source of utterance, the process of dialogue shift, and the critical movements that can judge the reasoning of utterance. As a result of the study, it was confirmed that the decision-making type of SSI topics and learners' personalities were influential in the decision-making process of SSI small group discussions. This research shows that there is a need to develop instructional materials considering decision-making types and learners' personality types of students as well as pre-service teachers for SSI discussion.

• Korean Journal of Optics and Photonics
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• v.24 no.4
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• pp.184-188
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• 2013

Two types of polymer-based optical splitters with $200{\mu}m$ large core are presented for optical multimode networks, such as smart home networks, intelligent automotive networks, etc. Optical splitters that have 1:1 symmetric and 9:1 asymmetric structure were fabricated by a ultra violet(UV)-imprint technology using a deep etched Si(silicon) master by the Bosch process. In this paper, we successfully fabricated the symmetric and asymmetric optical splitters with suitable optical network applications.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.6
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• pp.711-718
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• 2019

Spectrum analyzer and electromagnetic field meter were used to investigate the EM generation behaviour in different types of home electrical appliances. During microwave oven operation, the EM power measured at a point 30cm apart was measured in the range of 8~11mW/㎡, the strength of the low frequency magnetic field was 60~80mG and the electric field strength was measured at 150~160V/m. For smart phone wireless charging pad, it was measured at an electromagnetic power of 0.4mW/㎡, an electric field of 160 V/m and a magnetic field of 1mG at a point 10cm away. For microwave oven and wireless charging pad, if used within 10cm, the size of the electric field has been measured at a large value that exceeds the human body protection standard and may be hazardous to humans. On the other hand, home appliances such as TVs, hairdryers and refrigerators all showed very low levels of electromagnetic waves, electric fields and magnetic fields, with no harmful effects seen. For electromagnetic shielding, the metal Cu fabric and metal foil had a high level of EM shielding, while polymer films had a low EM shielding characteristic.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.23-29
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• 2023

Microfluidic reactors have been made to achieve significant development for the generation of new functional materials to apply in a variety of fields. Over the last decade, microfluidic reactors have attracted attention as a user-friendly approach that is enabled to control physicochemical parameters such as size, shape, composition, and surface property. Here, we develop a centrifugal microfluidic reactor that can control the flow of fluid based on centrifugal force and generate multifunctional particles of various sizes and compositions. A centrifugal microfluidic reactor is fabricated by combining microneedles, micro- centrifuge tubes, and conical tubes, which are easily obtained in the laboratory. Depending on the experimental control param- eters, including centrifuge rotation speed, alginate concentration, calcium ion concentration, and distance from the needle to the calcium aqueous solution, this strategy not only enables the generation of size-controlled microparticles in a simple and reproducible manner but also achieves scalable production without the use of complicated skills or advanced equipment. Therefore, we believe that this simple strategy could serve as an on-demand platform for a wide range of industrial and academic applications, particularly for the development of advanced smart materials with new functionalities in biomedical engineering.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.1
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• pp.30-35
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• 2013

Purpose: One of the current services, providing information to the patients and their guardians by using promotion materials induces positive responses and contributes to the improvement of the hospital reliability. Therefore, the objective of this study is to evaluate the effectiveness of audio visual materials, one of the means of promotion, as a way to give accurate medical information to resolve patient's curiosity about purpose and procedure of their examination and deplete complains about waiting which attributes negative effect to service quality assessment. Materials and Methods: 60 patients(mean age $53.97{\pm}12.24$, male : female = 26 : 34) who had $^{18}F-FDG PET/CT$ scan from July 2012 to August 2012 in Seoul Asan Medical Center were referred to the study. All of the patients having PET/CT scan were asked to watch an informative video material before the injection of radiopharmaceutical ($^{18}F-FDG$) and to fill in a questionnaire. Results: As a result of analyzing the contents of questionnaire, 52% of 60 patients had PET/CT scan for the first time and 72.4% of the patients read the PET/CT guidebook offered from their outpatient department or inpatient wards before their scan. After we searched the level of previous knowledge of the purpose and method of PET/CT scan, the patients answered 25.1% "know well", 34% "not sure", 40.9% "don't know" respectively. And 84.7% of the patients answered that watching the PET/CT guide video before the injection helps understanding what exam they were having and 15.3% of the patients did not. For the question asking ever the patients have experienced using our homepage or smart phone QR code to see the guide video before they visit out PET center, only 3.3% of them answered "yes". Lastly, the patients answered 60.1% "yes", 31.4% "so so" and 8.5% "no" respectively for the question asking whether watching the video makes the patients to fill the waiting time short. Conclusion: It is found that understanding of objective and method of the PET/CT scan and level of satisfaction was improved after the patients watched the guide video whether they had PET/CT scan before and read the PET/CT guidebook or not. Also, watching the video was effective for the reduction of perceptible waiting time. But while displaying the PET/CT guide video is useful for providing information about the scan and shortening the waiting time as one of the medical service, utilization of service was actually very poor because of the passive promotion and indifference of the patients about their examination. Therefore, from now on, it is necessary to construct the healthcare system which can be offered to more patients through the active promotion.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.1
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• pp.55-65
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• 2020

The use of underfill materials in semiconductor packages is not only important for stress relieving of the package, but also for improving the reliability of the package during shock and vibration. However, in recent years, as the size of the package becomes larger and very thin, the use of the underfill shows adverse effects and rather deteriorates the reliability of the package. To resolve these issues, we developed the package using a solid epoxy material to improve the reliability of the package as a substitute for underfill material. The developed solid epoxy was applied to the package of the application processor in smart phone, and the reliability of the package was evaluated using thermal cycling reliability tests and numerical analysis. In order to find the optimal solid epoxy material and process conditions for improving the reliability, the effects of various factors on the reliability, such as the application number of solid epoxy, type of PCB pad, and different solid epoxy materials, were investigated. The reliability test results indicated that the package with solid epoxy exhibited higher reliability than that without solid epoxy. The application of solid epoxy at six locations showed higher reliability than that of solid epoxy at four locations indicating that the solid epoxy plays a role in relieving stress of the package, thereby improving the reliability of the package. For the different types of PCB pad, NSMD (non-solder mask defined) pad showed higher reliability than the SMD (solder mask defined) pad. This is because the application of the NSMD pad is more advantageous in terms of thermomechanical stress reliability because the solderpad bond area is larger. In addition, for the different solid epoxy materials with different thermal expansion coefficients, the reliability was more improved when solid epoxy having lower thermal expansion coefficient was used.

• Fashion & Textile Research Journal
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• v.24 no.6
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• pp.667-685
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• 2022

This paper aims to investigate 4D printing materials for soft robots. 4D printing is a targeted evolution of the 3D printed structure in shape, property, and functionality. It is capable of self-assembly, multi-functionality, and self-repair. In addition, it is time-dependent, printer-independent, and predictable. The shape-shifting behaviors considered in 4D printing include folding, bending, twisting, linear or nonlinear expansion/contraction, surface curling, and generating surface topographical features. The shapes can shift from 1D to 1D, 1D to 2D, 2D to 2D, 1D to 3D, 2D to 3D, and 3D to 3D. In the 4D printing auxetic structure, the kinetiX is a cellular-based material design composed of rigid plates and elastic hinges. In pneumatic auxetics based on the kirigami structure, an inverse optimization method for designing and fabricating morphs three-dimensional shapes out of patterns laid out flat. When 4D printing material is molded into a deformable 3D structure, it can be applied to the exoskeleton material of soft robots such as upper and lower limbs, fingers, hands, toes, and feet. Research on 4D printing materials for soft robots is essential in developing smart clothing for healthcare in the textile and fashion industry.