• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.507-514
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• 2018

This study utilized latent growth curve modeling to investigate the trajectories of adolescent life satisfaction changes in middle and high school students. The effects of self-esteem, career identity, school learning activity, gender, and household earnings on life satisfaction changes were examined. Data was obtained from the Korea Child Youth Panel Survey (KYCPS), a longitudinal study following students for 7 years. Year 3-6 data was utilized. Results found that the life satisfaction trajectory resulted as a quadratic model in which individual differences were significant. Second, school learning activity used as a time variant variable had a positive significant effect on life satisfaction each year. Third, gender and self-esteem as time invariant variables had significant effects on initial levels while self-esteem had effects on the slope and quadratic change. Further implications and research issues are discussed.

• Journal of Korea Multimedia Society
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• v.13 no.12
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• pp.1778-1785
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• 2010

This paper proposes a new video-based method of analyzing human gait which is a highly variable dynamic process. It captures a human gait of varying directions as a trajectory in the phase space. The proposed method includes two options of a stochastic process model and a self-organizing feature map as the tool of feature space representation and analysis. Test results show that the model is highly intuitive and we believe it can contribute to our understanding of human activity as well as gait behavior.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.165-170
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• 1997

In this paper, we consider the aortic sinus baroreceptor, which is the most representative baroreceptors sensing the variance of pressure in the cardiovascular system(CVS), and propose heart activity control model to observe the effect of delay time in heart period and stroke volume under the regulation of baroreflex in arotic sinus. The proposed heart activity baroreflex regulation model contains CVS electric circuit sub-model, baroreflex regulation sub-model and time delay sub-model. In these models, applied electric circuit sub-model is researched by B.C.Choi and the baroreflex regulation sub-model transforms the input, the arotic pressure of CVS electric circuit sub-model, to outputs, heart period and stroke volume by mathematical nonlinear feedback. We constituted the time delay sub-model to observe sensitivity of heart activity baroreflex regulation model by using the variable value to represent the control signal transmission time from the output of baroreflex regulation model to efferent nerve through central nervous system. The simulation object of this model is to observe variability of the CVS by variable value in time delay sub-model. As simulation results, we observe three patterns of CVS variability by the time delay. First, if the time delay is over 2.5 sec, arotic pressure, stroke volume and heart rate is observed nonperiodically and irregularly. Second, if the time delay is from between 0.1 sec and 0.25 sec, the regular oscillation is observed. Finally, if time delay is under 0.1 sec, then heart rate and arotic pressure-heart rate trajectory is maintained in stable state.

• Journal of Environmental Science International
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• v.28 no.12
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• pp.1133-1145
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• 2019

Successful launch requires state-of-the-art launch vehicle technology and constant test operations, However, the meteorological threat to the launch vehicle flight trajectory is also an important factor for launch success. Atmospheric stability above the Naro Space Center at the this time is very important, especially because the initial flight operation can determine the success of the launch. Moreover, during the flight of launch vehicle with rapid pressure and thrust into the atmosphere, convection activity in the atmosphere may create environmental conditions that cause severe weather threats such as thunderstorms. Hence, studies of atmospheric instability characteristics over the Naro Space Center are a necessary part of successful launch missions. Therefore, the main aims of this study were to (1) verify the atmospheric stability index and convection activity characteristics over the Naro Space Center using radiosonde data observed from 2007 to 2018 by the Naro Space Center, (2) analyze changes in the atmospheric stability index according to monthly and seasonal changes, and (3) assess how the calculated atmospheric stability index is related to actual thunderstorm occurrence using statistical analysis. Additionally, we aimed to investigate the atmospheric characteristics above the Naro Space Center through the distribution chart of the atmospheric stability index during summer, when convection activity is highest. Finally, we assessed the relationship between lightning occurrence and unstable atmospheric conditions, through predictability analysis performed using the lightning observation data of the Korea Meteorological Administration.

• Journal of Oral Medicine and Pain
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• v.22 no.1
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• pp.167-181
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• 1997

The aim of this study was to investigate the relationship between velocity and factors which could affect the velocity of mandibular movement. For this study, 30 dental students without any masticatory signs and symptoms and 90 patients with temporomandibular disorders(TMD) were selected as the control group and the patients group, respectively. After determining Angle's classification and lateral guidance pattern of occlusion, clinical examination for TMD was perfomed. Velocity and distance of mandibular movements were recorded with BioEGN, reproducibility index of lateral excursions was evaluated by Pantronic(PRI) and BioEGN (BERI) activity in masticatory and cervical muscles were measured with BioEMG, and occlusal contact time and cross-arch unbalance(Total left-right statistics, TLR) on clenching were recorded with T-scan, respectively. The results of this study were as follows : 1. Velocity in the patients was faster than that in the controls in most mandibular movements, but on wide opening and closing movement, result was reverse. 2. Velocity on closing movements were faster than that on opening movements in the control group and a similar tendency was also shown in the patients group. 3. Patients with muscle disorders showed a tendency to have the highest value of velocity of all diagnostic subgroups, while patients with degenerative joint diseases showed a tendency to have the lowest value. 4. Patients with canine guidance showed a tendency to have the highest value of velocity in three subgroups by lateral guidance pattern, while patients with group function showed a tendency to have the lowest value. 5. BERI had a positive correlation with opening velocity on lateral excursion, while TLR had a negative correlation with opening velocity on swallowing. 6. EMG activity on clenching in masticatory muscles had negative correlation with opening velocity on border movements, and on swollowing, while the activity in rest correlated positively with opening velocity on border movements. 7. There were positive correlation between the velocity and the distance in long components of mandibular trajectory.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.1
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• pp.29-35
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• 2016

It is important to uniformly supply the fuel gas into the reaction activity area in polymer electrolyte membrane fuel cell (PEMFC). Recent studies have shown that the cell performance can be significantly improved by employing metal foam gas distributor as compared with the conventional bipolar plate types. The metal foam gas distributor has been reported to be more efficient to fuel transport. In this study, three-dimensional computational fluid dynamics (CFD) simulations have been performed to examine the effects of metal foam flow field design on the fuel supply to the reaction site. Darcy's law is used for the flow in the porous media. By solving additional advection equation for fluid particle trajectory, the gas transport has been visualized and examined for various geometrical configuration of metal foam gas distributor.

• The Journal of the Convergence on Culture Technology
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• v.5 no.1
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• pp.417-428
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• 2019

The aims of this study were to evaluate the prevalence of dysphagia in patients hospitalized with acute stroke and to identify factors associated with dysphagia. The study was conducted in a tertiary hospital and a total of 131 patients hospitalized with acute stroke (aged 34-92 years old, 58.0% male) were enrolled. The prevalence of dysphagia was 24.4% out of 131 participants and risk factors associated with dysphagia were age, neurological severity, oral health status, and dependence in activity of daily living of participants. Considering the long-term rehabilitation trajectory, it is necessary to apply the early screening and preventive nursing intervention for dysphagia during acute stage of stroke patient.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.565-573
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• 2004

In this paper, we proposed a heart activity control model for simulation of the aortic sinus baroreceptor, which was the most representative baroreceptor sensing the variance of pressure in the cardiovascular system. And then, the heart activity control model composed electric circuit model of the cardiovascular system with baroreflex control and time delay sub-model to observe the effect of time delay in heart period and stroke volume under the regulation of baroreflex in the aortic sinus. The mechanism of time delay in the heart activity baroreflex control model is as follows. A control function is conduct sensing pressure information in the aortic sinus baroreceptor to transmit the efferent nerve through central nervous system. As simulation results of the proposed model, we observed three patterns of the cardiovascular system variability by the time delay. First of all, if the time delay over 2.5 second, aortic pressure and stroke volume and heart rate was observed non-periodically and irregularly. However, if the time delay from 0.1 second to 0.25 second, the regular oscillation was observed. And then, if time delay under 0.1 second, then heart rate and aortic pressure-heart rate trajectory were maintained in stable state.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.138-148
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• 2019

Although social relation factors are confirmed to be closely associated with the depression level of the elderly through the preceding studies, there has been no specific study on subfactors of social relation that influence the trajectory of depression level. Considering such limitation, this study aims to analyze influencing subfactors of social relation on the trajectory of depression of the elderly. The 3rd, 4th, 5th, and 6th-year data of the Korean Longitudinal Survey of Ageing (KLoSA), which were provided by the Korea Employment Information Service (KEIS), were used in this study and 2,484 people aged 65 and over who responded to all the four-session surveys were used as final analysis subjects. In the result of the longitudinal study on depression level of the elderly aged 65 and over, the individual depression level was confirmed become lowered over time, showing a positive change. Also, the conditional model of Latent Growth Modeling (LGM) was applied to identify specific social network factors that influence the longitudinal change of depression level of the elderly. In the result of the analysis, it was found that initial value of depression of the elderly was influenced by whether they have a spouse or not, number of household member, meeting with close people, whether they do economic activity or not, whether they have a religion or not, etc. and the rate of change in depression of the elderly was influenced by number of household member, meeting with close people, expectation about life, etc. Through above results, this study suggests a need for specific programs and supports to continuously lower the depression level of the elderly.

• Archives of Plastic Surgery
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• v.49 no.2
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• pp.207-214
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• 2022

Background Fellowship training is becoming more popular in plastic surgery, with over half of residents pursuing advanced training. Here, we investigate how clinical and research fellowship training impacts career trajectory and scholastic achievement in academic plastic surgery. Methods Plastic surgery faculty members, from programs recognized by the American Council of Academic Plastic Surgeons, were identified using institutional Web sites. Data extracted included faculty demographics, training history, academic positions, and research productivity. Continuous and categorical variables were compared using t-tests and chi-square, respectively. Results In total, 949 faculty members were included, with 657 (69%) having completed fellowship training. Integrated program residents were more likely to complete a fellowship when compared with independent residents (p < 0.0001). Fellowship trained faculty were more likely to have graduated from a higher ranked residency program, in terms of both overall and research reputation (p = 0.005 and p = 0.016, respectively). When controlling for years in practice, there was no difference found in number of publications, Hirsch index (h-index), or National Institutes of Health funding between faculty between the two cohorts (p > 0.05). In a subanalysis comparing hand, craniofacial, microsurgery, and research fellowships, those who completed a research fellowship had higher h-indices and were more likely to reach full professor status (p < 0.001 and p = 0.001, respectively). Fellowship training had no effect on being promoted to Chief/Chair of departments (p = 0.16). Conclusion Fellowship training is common among academic plastic surgeons. In this study, both clinical and research fellowships were associated with various aspects of academic success. However, fellowship training alone did not affect attainment of leadership positions.