• Journal of rehabilitation welfare engineering & assistive technology
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• v.5 no.1
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• pp.27-33
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• 2011

Estimating algorithm of physical activity energy expenditure and physical activity intensity was implemented by using a tri-axial accelerometer motion detector of the SVM(Signal Vector Magnitude) of 3-axis(x, y, z). A total of 10 participants(5 males and 5 females aged between 20 and 30 years). The ActiGraph(LLC, USA) and Fitmeter(Fit.life, korea) was positioned anterior superior iliac spine on the body. The activity protocol consisted of three types on treadmill; participants performed three treadmill activity at three speeds(3, 5, 8 km/h). Each activity was performed for 7 minutes with 4 minutes rest between each activity for the steady state. These activities were repeated four weeks. Algorithm for METs, kcal and intensity of activities were implemented with ActiGraph and Fitmeter correlation between the data.

• The Korean Journal of Emergency Medical Services
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• v.17 no.2
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• pp.89-97
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• 2013

Purpose : The purpose of this study was to investigate the correlation between stress and maxillofacial injuries in male students. Methods : The subjects were 386 male students who were 18 years or more. Mean age was $20.99{\pm}2.80$ years. Data were collected using a self-reported questionnaire from March 7 to March 28, 2013. We surveyed maxillofacial injuries, mouth guards use and stress in male students majoring physical education. The data were analyzed by Cochran's Mantel-Haenszel, McNemar test and logistic multiple regression. Results : Those who had clenching habit and maxillofacial pain accounted for 48.7%. The pain was 3.23 folds higher in clenching habit than those who had not (OR=3.23, p <.001). The more stress they had, the more clenching habit (OR=2.13) and pain(OR=1.68) did they have. Within 2 years, those having maxillofacial injury accounted for 53.2% and 78.6% of them put on maxillofacial protection guard. In rule for mouth guard use, 39.9% had no maxillofacial injury. Maxillofacial injury was 2.41 folds higher in those who had no mouth guard usee (OR=2.41). Conclusion : Maxillofacial injury had a close correlation with mouth guard use and stress. Therefore, it is very important to establish the rule for mouth guard use in sports activities.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.9 no.1
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• pp.29-34
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• 2011

Purpose : The purpose of this study was to determine the effect of book bag handling styles and types of footwear on muscle activation of erector spine muscles and calf muscles. Methods : Ten participants took off their book bags and used sneakers to walk on a treadmill for 30 minutes. The following day, 10 participants put on their backpack with 10% of the weight and used sneakers to walk on the treadmill for 30 minutes. On the last day, 10 participants put on their backpack with 10% of the weight and used formal shoes to walk on the treadmill for 30 minutes. After walking on the treadmill at 3 mph for thirty minutes, we measured muscle activation in erector spine muscles and calf muscles. Results : The results of this study showed the activation of the erector spine muscles and the calf muscles significantly increased when walking with a book bag and the activation of the erector spine muscles and the calf muscles significantly increased when walking in formal shoes. Conclusion : Using a backpack and formal shoes increase muscle activity of erector spine muscles and calf muscles. The results of this study indicate that not using a backpack and wearing sneakers are more beneficial than that using a backpack weighted 10% and wearing formal shoes and can be recommended to adult women by clinicians.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.4
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• pp.191-195
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• 2017

The microstructures of nonwoven fabric with and without nanofibers used as a filter for air purification type mask were investigated using scanning electron microscope. Moreover, we proposed a new mask design which is effective in the improvement of the fine dust blocking property. When comparing to nonwoven fabrics of which an average diameter was $25{\mu}m$, the nanofibers formed by the electrospinning process had a tight mesh structure arranged irregularly with a relatively large specific surface area, which could be associated with their much smaller diameter ranging from 25 to 120 nm. Such a prominent structural feature at nanofibers led to mechanical adsorption of fine particles, resulting in enhancement of filtering behavior maintaining high permeability. In addition to the excellent performance of the mask filter, wearing the mask properly is expected to maximize the blocking property of fine dust. To meet such a requirement, a new mask design that can be closely attached to the face in order to effectively block fine dust entering the gap between the face and the mask.

• The Korean Journal of Community Living Science
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• v.27 no.3
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• pp.419-435
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• 2016

The purpose of the present study was to suggest the design requirements for Korean naval duty uniforms by evaluating the physiological and psychological comfort while wearing the uniforms. Two sets of wear trials were conducted with summer uniforms(eight young males) and winter uniforms(seven other young males). The summer wear trial consisted of 10-min rest, 60-min exercise, and 10-min recovery at an air temperature($T_{air} $) of $33^{\circ}C$ and 62%RH, followed by 10-min recovery at a $T_{air} $ of $23^{\circ}C$ and 64%RH(total 90 min). The winter wear trial consisted of 20-min rest at $T_{air} $ $20^{\circ}C$ and 55%RH, 25-min rest, 30-min exercise, and 35-min recovery at a $T_{air} $ of 0oC and 43%RH(total 110 min). Rectal and seven skin temperatures, clothing microclimate, heart rate, oxygen consumption, total sweat rate, and subjective perceptions were measured during the wear trials. By evaluating the experimental results from the wear trials, we extracted the following psycho-physiological design requirements to improve the current Korean naval uniforms: (1) It is important to maintain the skin temperatures within their comfort range, which depends on the body region (higher than $30^{\circ}C$ in winter, but less than $35^{\circ}C$ in summer). (2) In summer, the feet should be protected from the high heat of the ship floor surface. (3) In summer, sweat from the back should be sufficiently absorbed and allowed to dry quickly.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.2
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• pp.219-225
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• 2015

Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program.

• Fire Science and Engineering
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• v.24 no.5
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• pp.68-78
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• 2010

The purpose of this study, fire officials during the field activities find causes fugitive dust of containing asbestos is the seriousness of the phenomenon is a threat case and through questionnaires, during on-site activities to prevent exposure to asbestos is effectively. Analysis of the relationship to field activities of fire officials and about the dangers of asbestos dust, asbestos cancer caused by asbestos, and to protect fire officials from the same disease like malignant mesothelioma, by varying the conditions of irrational, fire officials at the scene activities in advance of a deadly hazard is aimed to eliminate through optimization of organizational management and a safe and pleasant working conditions for fire officials through the deadly hazards at the scene of action is aimed to obviate. Also according to asbestos exposure by wearing protective equipment as well as thoroughly strengthen firefighting, firefighting awards to recognize the seriousness of the hazard factors, disease and provide compensation to the legal system, for diseases not yet recognized officially recognized by disaster supplemented by institutional, fire officials to improve morale and working conditions, etc. versus expectations is to improve public services.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.254-260
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• 2013

Control signal generated from EEG (electro-encephalogram) can be used in many applications. In our study, for the purpose of developing practical instruments, a single channel system of providing reliable on/off signals was investigated since a multi-channel system can be bulky and expensive. Brainwaves in alpha, beta and theta bands were analyzed in order to extract reliable control signals when the concentration state reached. Rest and concentration states were differentiated based on power spectrum and histogram analysis. A better performance was obtained when the ratio between the beta and theta bands was used compared to the theta band only. In general, the longer the rest period before concentration, the lower success rate was. In addition, longer rest time produced longer detection time. Though there were individual differences, in case of 10-second rest time, a success rate of 91% and a detection time of 20.2 seconds was achieved on average.

• Journal of Convergence for Information Technology
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• v.7 no.3
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• pp.111-116
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• 2017

This study offers the possibility as a new product of souvenirs from cultural tourist sites with virtual reality contents, instead of a simple exhibit. Users can watch augmented reality contents on souvenirs, and use the virtual experience service of cultural tourist sites with VR viewer. It has 4K-class high-quality $360^{\circ}$ image capture to increase the immersion of users in virtual space, implement virtual reality space and intuitive UI interaction with users using IMU (Inertial Measurement Unit). It is also possible to apply various add-on functions, including 3D contents, through technical development to increase its marketability, and apply in other industries. In addition, the prototype of the souvenir and VR viewer will be made by using a 3D printer and such in order to apply the contents which will be introduced in this study. Various product expansions can be considered through consultation with the relevant companies for the use of ready-made products.

• Journal of Convergence for Information Technology
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• v.10 no.5
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• pp.143-149
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• 2020

The aim of this study was to examine the perceptions and attitudes of dental hygienists on the use of dental loupes. A questionnaire survey was conducted to 180 dental hygienists working at dental institutions and public health centers. 4.6% of all respondents answered that they use dental loupes currently, and 38.9% answered that they need to introduce dental loupes in the dental clinic. About half indicated that loupes were a benefit to improved vision(53%) and Improved clarity(44%). The most commonly reported disadvantages to loupes wear were limited depth of vision(39%) and overall dependency. It was confirmed that most dental hygienists did not use loupes, there was little interest in loupes. More research is needed on the effects of loupes in dental practice.