• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.2
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• pp.247-254
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• 2003

The paper presents the influence of spring dynamics and friction on dynamic responses in a spring-driven cam system. The characteristics of the friction on the camshaft are analyzed using the nonlinear pendulum experiment while the parameters of the friction model are estimated using the optimization technique. The analysis reveals that the friction of the camshaft depends on stick-slip, Stribeck effect and viscous damping. Spring elements are found to have much influence on the dynamic characteristics. Hence, they are modeled as four-degree-of-freedom lumped masses with equivalent springs. The appropriateness of the derived friction model and spring model is verified by its application to a vacuum circuit breaker mechanism of the cam-follower type.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2245-2247
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• 2003

The present DC Motor or STEP Motor have been used in electronic work or products. There have been researches that let those Motor improved more conveniently in controlling and measuring those than before. By controlling and measuring those, the convenience of users and the functions of products can be improved. In addition, the responding speed of whole system can be increased by improving it of controlling and measuring. Therefore it is necessary that we develop motor motion application. Because of this necessity, Neural-Network was used to improve the responding speed of controlling and measuring, and a new application was developed for the convenience of users. This thesis showed efficiency of controlling methodology by Neural-Network superior to others in correctness and speed. We are intend to verify its appropriateness though experimentations.

• Journal of the Korea Fashion and Costume Design Association
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• v.6 no.2
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• pp.21-33
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• 2004

The purpose of this study was to provide information on how to improve both the satisfaction and the current sizing system for the school uniform focused on middle and high school girls' students. For the satisfaction of their school uniform, there were statistical significance by the academic year in jacket design, blouse color, and skirt design in the case of middle school girls'. On the other hand, high school girls' evaluation of school uniform was significantly different in jacket color, jacket design, blouse color, textile of blouse, skirt color, and skirt design by the academic year. For the assessment of wearing motion, there was no significant difference by the grade in both middle school and high school girls'. However, it was shown more frequency of discomfort than that of comfort. For the evaluation of sizing fitness, the breadth of sleeve in jacket and the width of blouse were statistical significance in middle school girls' by the grade while the width of jacket, he breadth of sleeve in jacket, the length of blouse, the width of blouse and length of sleeve in blouse were different in high school students by the grade.

• 재활복지
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• v.21 no.2
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• pp.233-246
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• 2017

The present study is a basic study for application of Augmented Reality (AR) to verb teaching for children with language developmental disorders and is intended to examine validity for the list of verbs at the beginning of development. To confirm the validity of the verbs list, the appropriateness of the verbs was evaluated by three professors with certification of KSLP (Korean Speech-Language Pathologist) working in the department of Speech-Language Pathology at the university. The motion validity test was conducted by showing motion implemented as AR to eight master's students in Speech-Language Pathology major, having them record verbs that came to their mind, and evaluating in the conformity. The second motion validity test was conducted by using 5-point Likert scales to 87 undergraduates in Speech-Language Pathology major and having them see the motions in AR and marked the degrees to which them see the motions conform to the relevant verbs on the scales. Using the SPSS 21.0 program, descriptive statics analyses of the results were conducted. Through this all process, thirty verbs were selected as having content validity. It could be seen that when AR based communication system are applied, things and backgrounds that complement the insufficient movements of motions and help motion recognition should be also provided. In future studies, the 3D images of the AR based communication system will be complemented and the content validity will be verified with typically developing children and the children with language developmental disorders.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.4
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• pp.307-315
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• 2023

Korea controls the departure of vessels based on the Maritime Safety Act such that only ships with seaworthiness can navigate in bad weather, but scientific evaluation results and quantitative basis for the designation of ships subject to control are insufficient. Opinions for improvement are being raised for a reasonable departure control operation. The purpose of this study is to evaluate the adequacy of the current departure control standards through actual measurement of tugboats, which are the type of vessels subject to control when a wind and wave advisory is effective, and to present quantitative grounds for improvement of controls. A sensor was installed on the tugboat to measure the ship's three-axis motion and hull acceleration, and the hull motion performance was measured by operating in the sea area with a significant wave height of 3 m. The measured values were compared and analyzed based on seaworthiness evaluation factors and limit value standards. The actual ship was excluded from the current control standard according to tonnage, but as a result of the analysis, the pitch value exceeded the operation standard, and a risk to navigation safety existed. The results of this study suggest the need for additional actual measurement studies that can represent various ship types and specifications and review ship departure control targets.

• Fashion & Textile Research Journal
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• v.17 no.5
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• pp.781-792
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• 2015

This study aims to develop a spring/fall motorcycle jacket for quick service transporter. Depending on the results of the previous research, this study produced the tested jacket which was improved in material, pattern, and design. For the tested jacket, 100% polyester fabric excellent in strength, durability and abrasion-resistance was selected as a major material, and Cordura was used as a partial material to improve the strength and abrasion-resistance of the sleeve side lines, elbow and shoulder areas. The retro-reflection material was applied partially in order to improve visibility of the jacket in the night or in a dark place. A total of 7 pockets were composed in the jacket for the sufficient storage spaces. The functional design elements such as the 2-way zipper and the placket at the center front, the action pleats at the upper part of back armholes, the pit-zip at armpit were applied. In addition, the sleeve pattern was bent with the shape of elbow curvature in time of driving and the back length of the jacket was lengthened 4cm. As a result of the appearance assessment, there was a significant difference from the existing jacket in all items but chest size, shoulder width, cuffs circumference, and jacket hemline circumference. In motion adaptability and field activity appropriateness assessments, the assessment grade for all items was found to be commonly higher than that of the existing jacket, and thus, the tested jacket was assessed to be suitable for a motorcycle jacket design for the quick service transporters.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.206-217
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• 2009

The purpose of this study was to investigate the cause-effect relationship between motor impairments, hand function, gross motor function and activities of daily living (ADL) in children with cerebral palsy through the analysis of structural equation modeling. For this, 105 children with cerebral palsy (between 6 and 12 years old) were assessed about muscle tone and strength, range of motion, abilities of selective motor control, hand function, gross motor function and ADL. The results of this study were follows: Firstly, there were significant correlations between motor impairments of muscle tone, muscle strength, the abilities of selective motor control and ADL (p < .05); Secondly, a good correlation between the gross motor function, hand function and ADL was found in all children (p < .05); Thirdly, the appropriateness of research model was good. This study focused on exploration of the relationship between the motor impairment, gross motor function, hand function and ADL through structural equation modeling.

• Journal of Drive and Control
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• v.17 no.3
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• pp.33-46
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• 2020

We introduce a piece of special-purpose equipment for responding to disasters that has a dual-arm manipulator consisting of six-axis multi joints, and a master-slave operating system controlled by a wearable joystick for intuitive and convenient operation. However, due to the complexity and diversity of a disaster environment, training and suitable training means are needed to improve the interaction between the driver and equipment. Therefore, in this paper, a system that can improve the operator's immersion in the training simulation is proposes, this system is implemented in a virtual environment. The implemented system consists of a cabin installed with the master-slave operation system, a motion platform, visual and sound systems, as well as a real-time simulation device. This whole system was completed by applying various techniques such as a statistical mapping method, inverse kinematics, and a real-time physical model. Then, the implemented system was evaluated from a point of view of the appropriateness of the mapping method, inverse kinematics, the feasibility for real-time simulations of the physical environment through some task mode.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.185-188
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• 2019

In this paper, the towing stability of the LNG bunker barge is estimated. Currently, LNG bunkering barge is being developed as an infrastructure for the bunkering of LNG (Liquefied Natural Gas), an eco-friendly energy source. Since the LNG bunker barge are in the form of towed ship connected to the tow line, the towing stability of the LNG bunker barge is very important for the safety of not only the LNG bunker barge but also the surrounding sailing vessels. The numerical code for towing simulation was developed to estimate the towing stability of the LNG bunker barge at the initial design stage. The MMG(Manoeuvring Mathematical Group) model was applied to the equations of motion and the empirical formula was applied to the maneuvering coefficients so that they could be used in the initial design stage. To validity of the developed numerical code, it was compared with published calculation and model test results. Towing simulations were carried out according to with and without stern skeg of the LNG bunker barge using the developed numerical code. Through the results of the simulations, the appropriateness of the stern skeg area designed was confirmed.

• The Journal of Korean Society for Radiation Therapy
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• v.34
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• pp.61-72
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• 2022

Purpose: Conventional CBCT(Cone-beam Computed-tomography) caused an error in the target volume due to organ movement in the area affected by respiratory movement. The purpose of this paper is to evaluate the usefulness of accuracy and time spent using the Gated CBCT function, which reduces errors when performing RGRT(respiratory gated radiation therapy), and to examine the appropriateness of phase. Materials and methods: To evaluate the usefulness of Gated CBCT, the QUASAR^TM respiratory motion phantom was used in the Truebeam STx^TM. Using lead marker inserts, Gated CBCT was scaned 5 times for every 20~80% phase, 30~70% phase, and 40~60% phase to measure the blurring length of the lead marker, and the distance the lead marker moves from the top phase to the end of the phase was measured 5 times. Using Cedar Solid Tumor Inserts, 4DCT was scanned for every phase, 20-80%, 30-70%, and 40-60%, and the target volume was contoured and the length was measured five times in the axial direction (S-I direction). Result: In Gated CBCT scaned using lead marker inserts, the axial moving distance of the lead marker on average was measured to be 4.46cm in the full phase, 3.11cm in the 20-80% phase, 1.94cm in the 30-70% phase, 0.90cm in the 40-60% phase. In Fluoroscopy, the axial moving distance of the lead marker on average was 4.38cm and the distance on average from the top phase to the beam off phase was 3.342cm in the 20-80% phase, 3.342cm in the 30-70% phase, and 0.84cm in the 40-60% phase. Comparing the results, the difference in the full phase was 0.08cm, the 20~80% phase was 0.23cm, the 30~70% phase was 0.10cm, and the 40~60% phase was 0.07cm. The axial lengths of ITV(Internal Target Volume) and PTV(Planning Target Volume) contoured by 4DCT taken using cedar solid tumor inserts were measured to be 6.40cm and 7.40cm in the full phase, 4.96cm and 5.96cm in the 20~80% phase, 4.42cm and 5.42cm in the 30~70% phase, and 2.95cm and 3.95cm in the 40~60% phase. In the Gated CBCT, the axial lengths on average was measured to be 6.35 cm in the full phase, 5.25 cm in the 20-80% phase, 4.04 cm in the 30-70% phase, and 3.08 cm in the 40-60% phase. Comparing the results, it was confirmed that the error was within ±8.5% of ITV Conclusion: Conventional CBCT had a problem that errors occurred due to organ movement in areas affected by respiratory movement, but through this study, obtained an image similar to the target volume of the setting phase using Gated CBCT and verified its usefulness. However, as the setting phase decreases, the scan time was increases. Therefore, considering the scan time and the error in setting phase, It is recommended to apply it to patients with respiratory coordinated stereotactic radiation therapy using a wide phase of 30-70% or more.