• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.10
• /
• pp.887-894
• /
• 2013

Effective thermal conductivity of nanofluids has been predicted by using generalized self-consistent model and modified Eshelby model, which have been used for analysis of material properties of composites. A nanolayer between base fluid and nanoparticle, one of key factors for abrupt enhancement of thermal conductivity of nanofluids, is included in the analysis. The effective thermal conductivities of the nanofluid predicted by the present study show good agreement with those by models in the literature for the nanolayer with a constant or linear thermal conductivity. The predicted results by the present approach have been confirmed to be consistent with experiments for representative nanofluids such as base fluids of water or ethyleneglycol and nanoparticles of $Al_2O_3$ or CuO to be validated.

• Journal of Biomedical Engineering Research
• /
• v.32 no.1
• /
• pp.25-31
• /
• 2011

Blood glucose information is important for self regulation in daily life, but the frequency of self test remains to be only 17%(9 tests/month) in Korea, mainly due to pain during blood sampling. The present study tried to validate the clinical efficacy of the forearm as an alternative sampling site with minimized pain. Capillary blood was sampled both on the index finger($G_F$) and the forearm($G_A$), immediately followed by glucose measurements in 531 subjects, 25 who visited the Health Enhancement Center of C University Hospital, then venous blood($G_V$) was sampled for glucose test. The blood glucose concentration measured on the forearm was closer to the venous glucose than on the finger. The mean difference between $G_V$and $G_F$ was only 10 mg/dL well within the internationally accepted error limit. Error grid analyses of $G_F-G_V$, $G_A-G_V$ and $G_A-G_F$ revealed that the number of data points in regions A and B took 100%, 99.8%, and 97.9%, respectively. These results demonstrate the forearm blood glucose test is not only accurate but also clinically valid. Therefore, the forearm blood glucose test can be a useful way of self managing the chronic diabetes with minimized sampling pain.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.8
• /
• pp.3804-3814
• /
• 2013

This study examined the fitness of a structural model on the relationship among biological risk disposition, sociocultural risk factors, self-control, social support, and suicidal ideation for woman adolescents. Data were collected from December 3, 2012 to March 28, 2013 by questionnaires from 343 middle and high school students in the D metropolitan city. The data was analyzed by the SPSS and AMOS programs. Biological risk disposition, sociocultural risk factors, self-control, and social support showed a direct effect on suicidal ideation for woman adolescents, while biological risk disposition and sociocultural risk factors showed an indirect effect on suicidal ideation for woman adolescents. Biological risk disposition and sociocultural risk factors showed a direct effect on self-control and social support for woman adolescents. Based on the outcomes of this study, it is necessary to design an intervention program that emphasizes the reducement of biological risk disposition, sociocultural risk factors and enhancement self-control and social support in order to prevention woman adolescents' suicidal ideation.

• The Journal of the Korea Contents Association
• /
• v.20 no.9
• /
• pp.589-603
• /
• 2020

The purpose of this research is to 'know what causes the social isolation felt by marriage immigrant women'. Thus, a total of 253 cases of marriage immigrant women who use Multi-cultural Family Support Center in D city have been analyzed. The findings reveal that the factors influencing the sense of isolation in the social environment, experienced by immigrant women married to Koreans are: social support, family relationships, self-esteem, household income and economic activity. In other words, their strong sense of isolation from society will be lessened when they get more social support, are happy with their family relationships, have their improved self-esteem, earn higher household incomes and don't take part in undesirable economic activities. Based on the research results, this study makes suggestions, on both a political and practical level, to solve the above problem of social isolation faced by marriage immigrant women through their financial stability, desirable economic activities, healthy family relationships, the enhancement of self-esteem and the provision of generous social support for them.

• Korean Journal of Optics and Photonics
• /
• v.6 no.4
• /
• pp.288-295
• /
• 1995

We have studied about spatial wavefront analysis of a pulsed laser output beam by means of an imaging unstable ring resonator with an infinite Fresnel number. We have constructed a Newtonian telescope type NBUR (Negative Branch Unstable Ring) Nd:YAG laser with 4 plane mirrors. Provided that the NBUR resonator is under self imaging condition, the resonator could be reduced diffraction effects which were occuring to the beam transmitting through the circular aperture of scraper mirror in the resonator. We have observed enhancement in the spatial coherence of wavefronts of laser beam due to the iterative round trips of the self imaging beam inside the ring resonator. The information on the spatial wavefronts was determined by the fringe patterns from Mach-Zehnder interferometer and the fringe analysis by means of the Fourier transform method showed the distortion of wavefronts of less than 0.2), In comparison with a standing wave type resonator, we have confirmed that the spatial coherence of the NBUR Nd:YAG laser output beam was enhanced as much as 75%. s 75%.

• Journal of the Korea Convergence Society
• /
• v.10 no.11
• /
• pp.543-555
• /
• 2019

The purpose of this study was to define and clarify the concept of Shared decision-making (SDM) in patients with chronic disease. Walker and Avant's concept analysis process was used to analyze interdisciplinary convergence in SDM. SDM in patients with chronic disease can be defined by the following attributes: acknowledgment patients as 'self-care experts', the rights of self-determination, reversible negotiation, and patient-centered care. The antecedents of SMD consisted of situations where there is a need to make a decision from several treatment options of similar efficacy, decisional conflict, patient, family, and health provider's willingness to participate in the decision-making process, enough time and opportunity for SDM. The consequences occurring as a result of SMD were decrease decisional conflict, improvement health outcome, satisfaction, quality of life, enhancement self-management and self-efficacy with long-term, and living acceptably with the illness. Based on these results, a scale measuring SDM in patients with chronic disease is needed.

• Journal of Digital Convergence
• /
• v.16 no.11
• /
• pp.69-79
• /
• 2018

This study examines and measures the enhancement of intrinsic motivation in learners who have been part of the e-Learning system (www.englishbuddy.kr) for elementary-level English learning, developed based on the systematic application of the motivation theory as dictated by 'interest' and 'self-determination' and put into practice at 3,100 private tutoring institutions. According to the survey conducted on 328 learners in the e-Learning system inspired by the motivation theory and on 150 learners in other English programs, the former was found to have stimulated 'interest' and satisfied 'psychological desire' in the learners, leading to the development of 'specific strategies to motivate learners.' The study has clearly identified how learners are better motivated in the e-Learning environment, demonstrating its contributions to advancing e-Learning, building a practical e-Learning system based on a systematic motivation theory defined by 'interest' and 'self-determination,' and applying the system to some 16,000 learners at 3,100 private tutoring institutions.

• Journal of Digital Convergence
• /
• v.18 no.12
• /
• pp.353-362
• /
• 2020

This was a single group pretest-protest pre-experimental study designed to find out whether writing using media enhances creative convergence capacity. Data were collected from 30 C university students in C city, from March 1st to July 15th, 2020. Analysis was done using IBM SPSS 25.0 for frequency, percentage, average, standard deviation, and paired t-test. Creative problem solving ability was enhanced by an average of 0,63 points (p<.001), critical thinking tendency by 1.06 points (p<.001), self-leadership by 0,53 points (p<.001), and self-control by an average of 0.51 points, so was statistically significant (p=.001). Writing using media had the effect of improving creativity and integration capabilities. The results of this study are expected to be used as basic data for the development of educational programs for creativity and integration enhancement at university-level. Also, follow-up studies on the effectiveness of writing education by utilizing web media as text and tools simultaneously and customized university-level writing education utilizing media are required.

• Journal of The Korean Association of Information Education
• /
• v.18 no.2
• /
• pp.225-234
• /
• 2014

Robot programming allows students to plan an algorithm in order to solve a task, implement the algorithm, easily confirm the results of the implementation with a robot, and correct errors. Thus, robot programming is a problem solving process based on reflective thinking, and is closely related to students' metacognition. On this point, this research is conducted to develop a robot programming instructional model for tile enhancement of students' metacognition. The instructional processes of robot programming are divided into 5 stages (i.e., 'exploration of learning tasks', 'a teacher's modeling', 'preparation of a plan for task performance along with the visualization of the plan', 'task performance', and 'self-evaluation and self-reinforcement'), and core strategies of metacognition (i.e., planning, monitering, regulating, and evaluating) are suggested for students' activities in each stage. Also, in order to support students' programming activities and the use of metacognition, instructional strategies based on cognitive apprenticeship (i.e. modeling, coaching and scaffolding) are suggested in relation to the instructional model. In addition, in order to support students' metacognitive activities. the model is designed to use self-questioning, and questions that students can use at each stage of the model are presented.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.6
• /
• pp.585-592
• /
• 2011

The enhancement of the cold-start capability of polymer electrolyte fuel cells is of great importance in terms of the durability and reliability of fuel-cell vehicles. In this study, vanadium oxide films deposited onto the flat surface of metallic bipolar plates were synthesized to investigate the feasibility of their use as an efficient self-heating source to expedite the temperature rise during startup at subzero temperatures. Samples were prepared through the dip-coating technique using the hydrolytic sol-gel route, and the chemical compositions and microstructures of the films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy. In addition, the electrical resistance hysteresis loop of the films was measured over a temperature range from -20 to $80^{\circ}C$ using a four-terminal technique. Experimentally, it was found that the thermal energy (Joule heating) resulting from self-heating of the films was sufficient to provide the substantial amount of energy required for thawing at subzero temperatures.