• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.409-414
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• 2007

Nowadays, with the advancement of computational mechanics, and vehicle dynamics simulation linked up with virtual testing laboratory(VTL) and virtual proving ground(VPG) technologies has become a useful method for analyzing numerous driving performances and diverse noise/vibration characteristics. In this paper, the analytical vehicle model based on multi-body dynamics theory was developed to investigate the vibration characteristics according to various road conditions. For the purpose, the whole vehicle parameters, each vehicle's part parameter, and part connecting elements such as spring, damper, and bush were measured by an experiment. Also, the vehicle dynamics model, which includes the front suspension, rear suspension, steering, front wheel, rear wheel, and body subsystems has been constructed for computer simulation. With the developed vehicle dynamics model, three forces and three moments measured at each wheel center were applied to evaluate and analyze dynamics and vibration characteristics for miscellaneous road conditions.

• Korean Journal of Materials Research
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• v.25 no.9
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• pp.429-434
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• 2015

Resistance switching memory cells were fabricated using atomically dispersed Pt-$SiO_2$ thin film prepared via RF co-sputtering. The memory cell can switch between a low-resistance-state and a high-resistance-state reversibly and reproducibly through applying alternate voltage polarities. Percolated conducting paths are the origin of the low-resistance-state, while trapping electrons in the negative U-center in the Pt-$SiO_2$ interface cause the high-resistance-state. Intermediate resistance-states are obtained through controlling the compliance current, which can be applied to multi-level operation for high memory density. It is found that the resistance value is related to the capacitance of the memory cell: a 265-fold increase in resistance induces a 2.68-fold increase in capacitance. The exponential growth model of the conducting paths can explain the quantitative relationship of resistance-capacitance. The model states that the conducting path generated in the early stage requires a larger area than that generated in the last stage, which results in a larger decrease in the capacitance.

• Journal of the Korean Society of Safety
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• v.31 no.5
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• pp.82-88
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• 2016

The current risk assessment system do not reflect workers' various opinion. However, the worker actually are in the center of work field and are exposed to accidents. In this regard, this study suggests enhanced risk assessment by 'safety circle discussion' on workers' hand. The self-administered surveys on supervisors and workers were done for the effect analysis of the safety circle discussion. According to the question investigation, even though the current risk assessment causes difficulties in preventing accidents by unsafe behaviors, the worker-oriented safety circle discussion establishing measures for risk factors of each work type will be able to prevent accidents more effectively. Also, it can positively contribute to safety health awareness, industrial accident prevention, accurate recognition on risk factors, improving safety facilities/work conditions, workers' compliance to safety health rules. Lastly, most respondents agreed that it is necessary to form organic relationship through circle discussion and deriving safety inspections that workers participate.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.4
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• pp.417-425
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• 2012

This paper presents reference ZMP trajectory generation and implementation for a biped robot via linear inverted dumbbell model (LIDM), which can consider the effect of external momentum on the center of mass (COM) of robot. Based on a reference ZMP trajectory derived by using LIDM, a base trajectory is proposed not only to make the locomotion of robot similar to that of human but also to facilitate its implementation and tuning. In order to realize a dynamic walking using the proposed trajectory, compliance, impedance and ZMP tracking controllers are adopted together. Extensive experiments show that the proposed locomotion of a biped robot is stable and also, similar to that of human. Further researches on balance recovery of a biped robot will be carried out to guarantee its robust locomotion in combination with the proposed trajectory.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.2
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• pp.147-153
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• 2015

The International Maritime Organization has conducted SEEMP for reducing $CO_2$ emission from ships. The study was carried out by comparing the real application of three shipping companies with IMO guideline about SEEMP on the same category. This paper suggests a method to improve implementation of SEEMP more efficiently through a grasp of the problem from its real application. Improvements are error correction of Company EEOI, unification of EEOI data acquisition period, compliance of measurements for fuel-efficient operation, suggestion of $CO_2$ mass conversion factors for various fuel and EEOI goal setting through formal standards of the International Maritime Organization.

• Architectural research
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• v.11 no.2
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• pp.27-34
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• 2009

The purpose of this study is to investigate the problem of crack repair materials and methods in existing concrete structure and to propose the effective injection method on crack repair by packer type. The result of this study is as follows. It is investigated that the crack width in the inner matrix of concrete structure is decreased about 30-40% than that in the surface of the concrete structure. Also it is showed that the possibility which could be monolithic with injection part became higher if the injection part is installed near to surface of concrete on the punching method to vertical direction against crack area. The injection of repair material can be poured smoothly under about $10N/mm^2$ pressure on the condition that cracks are monolithic with injection part without dust by drill. The method which is effective injection for a repair material is the punching method in compliance with coredrill. But, the research continuously is necessary about minimum injection pressure.

• Asian Journal for Public Opinion Research
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• v.8 no.3
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• pp.297-323
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• 2020

The relationship between compliance with behaviors recommended to prevent the spread of COVID-19 and media exposure, negative emotions, and risk perception was examined using regression analyses of data from KAMOS, a nationally representative survey of South Korean adults. The strongest predictor of preventive behaviors in general was negative emotions, which had the largest βh (.22) among the independent variables considered. The eight negative emotions, identified using factor analysis of a series of 11 emotions, were anger, annoyance, fear, sadness, anxiety, insomnia, helplessness, and stress. Negative emotions themselves were influenced most strongly by the respondent's anxiety over social safety (βe=.286), followed by prediction of COVID-10 spread (β=.121, p<.001) and perceived risk of COVID-19 infection (β=.70, p=.023). Females (β=-.134) and those who felt less healthy (βo=-.097) experienced more negative emotions. Media exposure and increased media exposure both have significant relationships with negative emotions and both a direct and indirect impact on the adoption of preventive measures. Women, older people, and healthier people perceived greater risks and engaged in more preventive behaviors than their counterparts.

• Research in Community and Public Health Nursing
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• v.18 no.1
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• pp.112-122
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• 2007

Purpose: The purpose of this study was to identify and profile distinct subgroups of patients with hypertension based on knowledge, attitudes, and behavior regarding their medication and health lifestyle. Method: A descriptive-exploratory research design was employed. Two hundred and twenty-three patients with hypertension using W Public Health Center were randomly recruited on the basis of being over 30 of age. Upon the receipt of their written consents, direct interview with a structured questionnaire were conducted by a public health nurse. Descriptive statistics and $X^2-test$ were utilized. Results: Three subgroups were identified. Group I members had a low score on all three factors including knowledge, attitudes and behavior related to medication and health lifestyle. Group II members had a low score on one or two of the factors. Group III members had a high score on all three factors. The three subgroups were significantly associated with education level, economic status, non-smoking and non-drinking. Conclusions: Further research should be conducted to validate these findings and test tailored nursing intervention for patient compliance.

• Journal of Korean Biological Nursing Science
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• v.18 no.4
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• pp.288-295
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• 2016

Background: This study was conducted in order to survey the current state of cleaning, disinfection, rinsing, drying, and storage of gastrointestinal endoscopes. Methods: Eighty hospitals were selected through convenient sampling. Self-reported questionnaire was distributed from September 14 to October 10 in 2015. Results: The response rate was 67.5% (54/80). In 88.9% of the hospitals, reprocessing was performed in a cleaning space separated from the laboratory and 88.9% used an enzymatic cleaner. Disinfectants used were ortho-phthalaldehyde in 63.0%, and paracetic acid in 33.3%. Eighty seven percent of the hospitals used test strips in order to test the effective concentration of disinfectant and in 61.1%, drying was done through passing air and over 70% alcohol. Microbial culture for the quality control of gastrointestinal endoscopes was performed in 77.8%. In the comparison of the adequacy of gastrointestinal endoscope reprocessing, it was observed that gastrointestinal endoscopes were reprocessed more adequately in larger and tertiary care hospitals. Conclusion: Gastrointestinal endoscopes were reprocessed in similar manners, but there were differences in the detailed process. It is still necessary to segment reprocessing into stages, to prepare standardized guidelines, and to monitor compliance with the guidelines.

• Smart Structures and Systems
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• v.14 no.4
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• pp.659-678
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• 2014

The study is aimed at investigating the feasibility of a high TRL solution for a wing flap segment characterized by morphable camber airfoil and properly tailored to be implemented on a real-scale regional transportation aircraft. On the base of specific aerodynamic requirements in terms of target airfoil shapes and related external loads, the structural layout of the device was preliminarily defined. Advanced FE analyses were then carried out in order to properly size the load-carrying structure and the embedded actuation system. A full scale limited span prototype was finally manufactured and tested to: ${\bullet}$ demonstrate the morphing capability of the conceived structural layout; ${\bullet}$ demonstrate the capability of the morphing structure to withstand static loads representative of the limit aerodynamic pressures expected in service; ${\bullet}$ characterize the dynamic behavior of the morphing structure through the identification of the most significant normal modes. Obtained results showed high correlation levels with respect to numerical expectations thus proving the compliance of the device with the design requirements as well as the goodness of modeling approaches implemented during the design phase.