• Journal of the Korean Society for Precision Engineering
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• v.18 no.11
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• pp.107-115
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• 2001

Most of rotating machineries supported by contact bearing accompany lowering efficiency, vibration and wear. Moreover, because of vibration, which is occurred in rotating shaft, they have the limits of driving speed and precision. The rotor system has parametric variations or external disturbances such as mass unbalance variations in long operation. Therefore, it is necessary to research about magnetic bearing, which is able to support the shaft without mechanical contact and to control rotor vibration without being affected by external disturbances or parametric changes. Magnetic bearing system in the paper is composed of position sensor, digital controller, actuating amplifier and electromagnet. This paper applied the robust control method using quantitative feedback theory (QFT) to control the magnetic bearing. It also proposed design skill of optimal controller, in case the system has structured uncertainty, unstructured uncertainty and disturbance. Reduction of vibration is verified at critical rotating speed even external disturbance exists. Unbalance response, a serious problem in rotating machinery, is improved by magnetic bearing using QFT algorithm.

• The Research Journal of the Costume Culture
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• v.26 no.6
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• pp.966-981
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• 2018

Consumers' desire for beauty has become a driving force in the beauty service industry which was further developed through specialization and segmentation. Nail-care service, which is one of the beauty services, is showing rapid growth, and intense competition among salons has become apparent. Thus, service management method and marketing strategy are required for customer satisfaction. Therefore, in this study, we tried to classify the nail-care services on the basis of systematization and realization of its characteristics which are fundamental when developing management and marketing strategies. The subjects of this study were women in their 20s and above living in Seoul, Gyeonggi, and Incheon areas. As a result, the nail-care service factors are classified as "external environment" (interior, celebrity, newness), "internal environment" (equipment and products, cleanliness, and environment), "location" (location and transportation convenience), "reputation" (good reputation), "technician skill," "kindness," "relationship" (relationship, empathy, and affinity), and "price and discount." The consumer types of nail-care services were classified into three groups according to the degree of involvement of these concept systems. These results can be used as marketing basics and will be the basis for studying marketing strategies. However, the consideration of setting up a marketing strategy for each consumer type will be presented in a follow-up study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.254-255
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• 2016

The Human have sought convenience through advancing Science skill, The Generation that unman control all machine have came. the unman - vehicle have used and applied flight, ship, car, manufacturing all over the world. plus which, that is researching. but pros and cons of unman - vehicle is that unman control machine, It mean that unman - vehicle have high possibility which have collision with obstacle on driving. I will show you that this evading collision will be made from fuzzy control and video recognition and sensor recognition.I look for good effect for this system.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.37-45
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• 2019

In recent years, the emergence of virtual reality (VR Virtual Reality) technology has provided a new model of safety education, enabling users to learn and respond to disasters in a virtual safety education environment. However, the related VR products related to domestic and foreign R & D are relatively simple, there is no practical training on specific accident, and it is not practical enough to play a sufficient role in safety education. In this paper, the problems and disadvantages of VR technology applied in the field of automobile safety education as an example of automobile accident among the types of disasters are examined, and a system framework of automotive safety education based on VR technology is proposed. The vehicle safety education system proposed in this paper will help users to improve driving safety consciousness, to acquire safety knowledge in driving, and to acquire driving safety skill which is very important for automobile safety education. In addition, the design and production methods of safety education based on VR technology are considered to have important reference implications for the application of modern teaching and teaching theory by integrating with VR technology and developing related teaching materials products and finally introducing education.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.178-185
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• 2018

A self-report evaluation is used to prevent driving accidents by elderly drivers. The majority of normal older adults may have mild cognitive impairment with reduced cognitive function. These depressed cognitive functions may be variables that affect the performance of elderly drivers. This study confirmed the cognitive functions that affect the self-reported evaluation for elderly drivers with mild cognitive impairment. Based on the results of the Korean Version of the Montreal Cognitive Assessment, 103 elderly drivers were classified into mild cognitive impairment and normal groups of elderly drivers. The Korean-Drivers 65 plus scores used in the self-reported evaluation of the two groups were compared, and the cognitive functions affecting the evaluation were analyzed. Results found the mild cognitive impairment group showed a significantly lower evaluation performance compared to the normal group, and the self-reported evaluation results of the elderly driver with mild cognitive impairment showed a significant correlation between visuoconstructional skills and delayed recall. As a result of regression analysis, the visuoconstructional skill was identified as the cognitive function with the strongest influence on the self-reported evaluation performance. Delayed recall was also found to have a partial effect but not at the level of altering the self-reported evaluation results of the elderly driver with mild cognitive impairment.

• Journal of National Security and Military Science
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• s.7
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• pp.271-303
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• 2009

"Ubiquitous sensor network" definition is this-Someone attaches electro-magnetic tag everything which needs communication between man to man, man to material and material to material(Ubiquitous). By using attached every electro-magnetic tag, someone detects it's native information as well as environmental information such as temperature, humidity, pollution and infiltration information(Sensor). someone connects it realtime network and manage generated information(Network). 21st century's war is joint combined operation connecting with ground, sea and air smoothly in digitalized war field, and is systematic war provided realtime information from sensor to shooter. So, it needs dramatic development on watch reconnaissance, command and control, pinpoint strike etc. Ubiquitous computing and network technologies are essential in national defense to operate 21st century style war. It is possible to use many parts such as USN combined smart dust and sensor network to protect friend unit as well as to watch enemy's deep area by unmanned reconnaissance, wearable computer upgrading soldier's operational ability and combat power dramatically, RFID which can be used material management as well as on time support. Especially, unmanned watch system using USN is core part to transit network centric military service and to get national defense efficiency which overcome the dilemma of national defense person resource reducing, and upgrade guard quality level, and improve combat power by normalizing guardian's bio rhythm. According to the test result of sensor network unmanned watch system, it needs more effort and time to stabilize because of low USN technology maturity and using maturity. In the future, USN unmanned watch system project must be decided the application scope such as application area and starting point by evaluating technology maturity and using maturity. And when you decide application scope, you must consider not only short period goal as cost reduction, soldier decrease and guard power upgrade but also long period goal as advanced defense ability strength. You must build basic infra in advance such as light cable network, frequency allocation and power facility etc. First of all, it must get budget guarantee and driving force for USN unmanned watch system project related to defense policy. You must forwarded the USN project assuming posses of operation skill as procedure, system, standard, training in advance. Operational skill posses is come from step by step application strategy such as test phase, introduction phase, spread phase, stabilization phase and also repeated test application taking example project.

• Korean Journal of Culture and Social Issue
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• v.8 no.1
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• pp.41-59
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• 2002

The present study explored the major behavior patterns of drivers and the environmental settings having an effect on traffic accident using the data collected from drivers and traffic police. Drivers and traffic police read questionnaire which contain the passible causes of traffic accident and selected the major causes on the basis of their latest accidents. Unexperienced drivers were forced to answer the questionnaire by referring to their friends and neighborhoods. The results showed that the major causes of traffic accident were connected with the driver's factors. The most important cause of traffic accidents was inattention/incautiousness. The next were lack of competence, skill, and experience. One interesting fact was that drivers and traffic police attributed differently. Drivers pointed out the lack of ability coping with an emergency and the insufficient skill of defensive driving as causes of the traffic accident. On the other hand, traffic polices indicated the intentional violations such as the disregard for traffic rules, trespassing on the central line of the roadway, speed limit violation, and breaking into the vehicle's line. The implications for appling the this results to driver education institutions were discussed.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.6.1-6.15
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• 2023

Background: Polycyclic aromatic hydrocarbons (PAHs) are occupational and environmental pollutants generated by the incomplete combustion of organic matter. Exposure to PAHs can occur in various occupations. In this study, we compared PAH exposure levels among occupations based on 4 urinary PAH metabolites in a Korean adult population. Methods: The evaluation of occupational exposure to PAHs was conducted using Second Korean National Environmental Health Survey data. The occupational groups were classified based on skill types. Four urinary PAH metabolites were used to evaluate PAH exposure: 1-hydroxypyrene (1-OHP), 2-naphthol (2-NAP), 1-hydroxyphenanthrene (1-OHPHE), and 2-hydroxyfluorene (2-OHFLU). The fraction exceeding the third quartile of urinary concentration for each PAH metabolite was assessed for each occupational group. Adjusted odds ratios (ORs) for exceeding the third quartile of urinary PAH metabolite concentration were calculated for each occupational group compared to the "business, administrative, clerical, financial, and insurance" group using multiple logistic regression analyses. Results: The "guard and security" (OR: 2.949; 95% confidence interval [CI]: 1.300-6.691), "driving and transportation" (OR: 2.487; 95% CI: 1.418-4.364), "construction and mining" (OR: 2.683; 95% CI: 1.547-4.655), and "agriculture, forestry, and fisheries" (OR: 1.973; 95% CI: 1.220-3.191) groups had significantly higher ORs for 1-OHP compared to the reference group. No group showed significantly higher ORs than the reference group for 2-NAP. The groups with significantly higher ORs for 1-OHPHE than the reference group were "cooking and food service" (OR: 2.073; 95% CI: 1.208-3.556), "driving and transportation" (OR: 1.724; 95% CI: 1.059-2.808), and "printing, wood, and craft manufacturing" (OR: 2.255; 95% CI: 1.022-4.974). The OR for 2-OHFLU was significantly higher in the "printing, wood, and craft manufacturing" group (OR: 3.109; 95% CI: 1.335-7.241) than in the reference group. Conclusions: The types and levels of PAH exposure differed among occupational groups in a Korean adult population.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.147-152
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• 2020

The purpose of this study was to develop an auxiliary device useful for promoting continued participation in the golf among young golfers and female beginner-level golfers who were gradually increasing in number but often losing interest in the golf and gave up playing golf due to difficulty with posture, boredom from golf itself, slow improvement of skill, etc., in the process of learning the golf. For that, a hardware device fitted with various sensors was attached to the lower part of golf club grip to develop a platform capable of collecting and transmitting the data on each golfer's swing posture, driving distance, etc. If a smartphone app, which can analyze and store those data, is developed and synchronized, each golfer's postures can be identified and golfers can correct the posture on their own. Moreover, the smartphone app provides the contents for self-comparison and comparison with others and will be able to infuse the beginner-level golfers with internal motivation for continued participation in the golfing exercise if the game-type elements are added.

• Korean Journal of Applied Biomechanics
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• v.27 no.4
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• pp.239-245
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• 2017

Objective: The bobsleigh shoes used in the start section are one of the most important equipment for improving the competition. Despite the importance of the start section, there are no shoes that are specific for bobsleigh athletes in Korea and Korean athletes have to wear sprint spike shoes and practice the start instead of wearing bobsleigh shoes. The objective of the present study was to provide data for improving the performance of Korean bobsleigh athletes by investigating the differences in their split time, plantar pressure, and forefoot bending angle based on skill levels at the start of a run under the same conditions as training conditions. Method: Six Korean bobsleigh athletes were divided into two groups, superior (n=3) and non-superior (n=3). A digital speedometer measured the split time at the start; the Pedar-X system (Novel, Germany) measured plantar pressure. Plantar pressures and split times were measured as the athletes pushed a bobsleigh and sprinted at full speed from the start line to the 10-m mark on the bobsleigh track. An ultra-high-speed camera was used to measure the forefoot bending angle during the start phase. Results: Significant between-group differences were found in split times (p<.000; superior = 2.38 s, non-superior = 2.52 s). The superior group had a larger rearfoot (p<.05) contact area, maximum rearfoot force (p<.01), and a larger change in angles 3 and 4 (p<.05). Conclusion: At the start of a bobsleigh run, proper use of the rearfoot for achieving effective driving force and increasing frictional resistance through a wider frictional force can shorten start time.