• The Journal of Advanced Prosthodontics
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• v.14 no.2
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• pp.88-95
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• 2022

PURPOSE. This study investigated the accuracy of full-arch intraoral scans obtained by various scan strategies with the segmental scan and merge methods. MATERIALS AND METHODS. Seventy intraoral scans (seven scans per group) were performed using 10 scan strategies that differed in the segmental scan (1, 2, or 3 segments) and the scanning motion (straight, zigzag, or combined). The three-dimensional (3D) geometric accuracy of scan images was evaluated by comparison with a reference image in an image analysis software program, in terms of the arch shape discrepancies. Measurement parameters were the intermolar distance, interpremolar distance, anteroposterior distance, and global surface deviation. One-way analysis of variance and Tukey honestly significance difference post hoc tests were carried out to compare differences among the scan strategy groups (α = .05). RESULTS. The linear discrepancy values of intraoral scans were not different among scan strategies performed with the single scan and segmental scan methods. In general, differences in the scan motion did not show different accuracies, except for the intermolar distance measured under the scan conditions of a 3-segmental scan and zigzag motion. The global surface deviations were not different among all scan strategies. CONCLUSION. The segmental scan and merge methods using two scan parts appear to be reliable as an alternative to the single scan method for full-arch intraoral scans. When three segmental scans are involved, the accuracy of complete arch scan can be negatively affected.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.3
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• pp.33-42
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• 2018

Purpose : The purpose of this study was to investigate the characteristics of the Flex-OA shoe, a specific functional shoe, in terms of the range of motion (ROM) of hip and knee joint during walking when compared to a standardized shoe. Methods : Twenty-six healthy adults (18 males, 6 females) participated in this study. Subjects performed 8 walking trials consisting of two different shoe conditions to evaluate the hip and knee ROM using a three-dimensional motion capture system. Visual 3D motion analysis software was finally used to coordinate the kinematic data. Result : The total ROM and maximal abduction range of the hip joint in the coronal planes when wearing the Flex-OA shoe were significantly increased during walking compared to wearing a standard shoe (p<.05). On the other hand, significantly increased ROM was observed in the sagittal plane when wearing the Flex-OA shoe in the knee joints compared to a standard shoe (p<.05). Conclusion : Although clinical application of the specific functional shoe has known clearly positive effects on knee moments, the results of this study could provide important clues to explain the background of these effects in terms of the hip and knee joints when applying a specific functional shoe.

• Journal of Sensor Science and Technology
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• v.18 no.6
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• pp.461-466
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• 2009

This paper represents a piezoelectric ultrasonic linear actuator with flexural vibration mode. The actuator is composed of two piezo ceramics, the elastic body, and the connecting tip. It is driven by the frictional force between the connecting tip and the linear motion guide. Unimorph actuators have flexural vibration. Its middle point is fixed so that suitable to the flexural vibration of $3/2\lambda$. These vibrations contribute to elliptical motion by mixed mode between longitudinal and transverse mode. It was generated when the ultrasonic electrical signals with 90 degree phase difference are applied to two ceramics. A linear movement can be easily obtained using the elliptical motion. The ATILA, FEM simulator has been used to design actuator and verify the kinetic and dynamic analysis. We used the ceramics of $20\times10\times1$ mm size and confirmed the flexural vibration of the $3/2\lambda$ at the 79 kHz through the scanning of 3D-vibrometer. The maximum velocity of actuator was 221 mm/sec and the thrust force of actuator was 2.7 N in 200Vp-p of additional voltage.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.3
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• pp.182-190
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• 1993

A numerical technique is presented to calculate the motions of 6 d.o.f and mooring tensions for a catenary moored floating breakwater. The breakwater may be subjected to the 3-D combination of regular or irregular waves and stationary forces. The added mass coefficients at the infinitive frequency of input wave and the variations of damping and exciting force coefficients are calculated using the source distribution method. The coefficients are used to constitute motion equations in time domain which are solved by WiIson-$\theta$ method. The solutions agree quite well with either static displacement determined from Newton method under the stationary force only or 6 d.o.f determined from the frequency domain analysis under regular wave only. An example analysis is also done for a floating breakwater to demonstrate its applicability.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.155-159
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• 2005

High speed presses with high resolution in semiconductor lead frame manufacturing process are needed . But high speed operation accompanies mechanical vibration. therefore optimized kinematic structure to minimize vibration is required for a high speed press. And the growing competition in the industry asks a press with low cost, high speed, high resolution, and high pressing force, For this purpose a high speed press was modeled with 3D CAD solid modeling system and dynamic analysis were performed with CAE S/W for multibody dynamic analysis, Through these analyses a motor appropriate to a high speed press was selected and link structure for feeding system of the press was modified to reduce vibration. To perform this analysis working Model which is 2D kinematics and dynamic analysis software was used.

• Journal of Information Technology Applications and Management
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• v.24 no.2
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• pp.97-112
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• 2017

This paper aims to research the technology level of sports industry, through analyzing the technology gap between Korea and other major countries (USA, Europe, Japan, and China), and provide a list of technologies to be prioritized for R&D investment by conducting an analysis of the strategic importance of various element technologies. The results of the analysis showed that the technology level of Korean sports industry currently stands at 70.5% of the country with the most advanced technology (the USA), and that the technology gap amounts to 4.8 years. It was also found that the USA is the country with the most advanced technology (100%) at present, followed by Europe (91.1%), Japan (88.3%), Korea (70.5%), and China (61.2%). To reduce the technology gap, we established a Strategic Zone (SZ) and derived three element technologies including 'design and production technologies for sports and game equipment' in the $1^{st}$ tier, nine element technologies including '3D motion analysis and simulation technology' in the $2^{nd}$ tier, and four element technologies including 'fitness/health promotion and management technology' in the $3^{rd}$ tier. The significance of this research is that it included five major technology categories of the sports industry in its analysis, selected an expert on sports industry technologies using the delphi method. Therefore, the results of this study may be suitable for use as basic data in establishing the R&D strategy for the future development of the sports industry.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.989-999
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• 2006

In this paper, numerical analysis method to perform linear dynamic analysis of bridge considering the road surface roughness and bridge-vehicle interaction when vehicle is moving on bridge is presented. The vehicle and bridge are modeled as three-dimension where contact length of tire and pitching of tandem spring are considered and single truck with 2-axles and 3- axles, and tractor-trailer with 5-axles are modeled as 7-D.O.F., 8-D.O.F., and 14-D.O.F., respectively. Dynamic equations of vehicle are derived from the Lagrange's equation and solution of the equation is obtained by Newmark-${\beta}$ method. The surface roughness of bridge deck for this analysis is generated from power spectral density (PSD) function. Beam element for the main girder, shell element for concrete deck and rigid link between main girder and concrete deck are used. The equations of the motion of bridges are solved by mode-superposition procedures. The proposed procedure is validated by comparing the results with the experimental data by Whittemore and Fenves.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.590-595
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• 2007

It is important to predict the collision behavior of a train consist to improve its crashworthiness. To analyze crash behavior of train, four kinds of methods are mainly used so far. The first is method using multibody dynamics to predict the gross motion of the train set. The second uses 3D FE model to apply the section analysis method in order. The third is used to deduce design specification and evaluate the crashworhiness of a train by using 1D model. The last is to constitute 2D model to check overriding and coupling devices. The train evaluation procedures are so complex that it is difficult to understand or deal with. In this study, VTM for railway train was introduced to simplify the procedures. VTM involves 3D models, 1D models and dynamic components such as suspension and coupling. The method using hybrid concept model makes it possible to do all the things that are mentioned above. To analyze crash behavior tendency of VTM, the model was simulated and the simulation results were discussed.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.631-634
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• 2006

The national standard physique research of Korea is being conducted every 5$\sim$6 year term after its first research was started in 1979. The result of the national physique research was reflected in manufactured goods design of allied industries such as clothing, shoes, furniture. In this thesis, we measured anthropometry value for every bodily figurative classification after dividing users according to gender, age, bodily figure using the result of the national standard physique research. We constructed 3D character through the process of analyzing interrelation of measured anthropometry and measuring representative category. For the process for organization, we measured anthropometry which can express sports action of golf, tennis and etc effectively. We made it by presenting measurement which is able to form each type of 3D character after the category was decided. Quantitative and objective valuation for posture and action became possible by developing visible information offer and posture action analysis protocol in theoretical approach for analysis of posture and action in sports.

• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.29-47
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• 2003

This study is to analyze the kinematic variables in release motion of discuss throwing. For the matter, 5 people from the national team and collegiate discuss throwing in the year 2001 were chosen as the subjects and two S-VHS video cameras set in 60frames/sec were used for recording their motions. Coordinated raw positions data through digitizing are smoothing by butter-worth 's low-pass filtering method at a cut off frequency 6.0Hz. and the direct linear transformation(DLT) method was employed to obtain 3-D position coordinates. The conclusions were as follows; 1. The better record players showed the shorter approach time in the last support phase. 2. In the displacement CG, the better record players showed the shorter displacement in medial-lateral direction, and the longer displacement in horizontal direction. In the motion, the COG showed longer displacement vertical direction. 3. The better record players showed the faster horizontal velocity than vertical velocity in the release. 4. The better record players showed to take the posture of vertical axis in the release.