• Journal of the Korea Convergence Society
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• v.11 no.3
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• pp.245-252
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• 2020

The present study aimed to identify the effects of the trunk stability exercise on functional movement, dynamic balance, and trunk stability in patients with chronic low back pain, and to compare the difference among yoga exercise, pilates exercise and core exercise. Forty-three patients with chronic low back pain were divided into three groups; 15 yoga groups, 15 pilates groups, and 13 core exercise groups. All subjects were tested the Functional movement, dynamic balance, and trunk stability using Functional Movement Screen (FMS), Lower Quater Y-Balance Test (YBT-LQ) and Trunk Stability Test (TST), respectively, and after each 8-week exercise program was applied, all variables were retested. After exercising during 8 weeks, FMS, YBT-LQ and TST scores of all three groups were significantly improved, compared to before, but there were no interaction effect among three groups depending on application of exercise program. These results showed that yoga, pilates and core exercise help to improve functional movement, dynamic balance and trunk stability in adults with chronic low back pain.

• Geomechanics and Engineering
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• v.11 no.4
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• pp.571-585
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• 2016

The crest of the Pubugou central core rockfill dam (CCRD) cracked in the first and second impounding periods. To evaluate the safety of the Pubugou CCRD, an inversion analysis of the constitutive model parameters for rockfill materials is performed based on the in situ deformation monitoring data. The aim of this work is to truly reflect the deformation state of the Pubugou CCRD and determine the causes of the dam crest cracks. A novel real-coded genetic algorithm based upon the differences in gene fragments (DGFX) is proposed. It is used in combination with the radial based function neural network (RBFNN) to perform the parameters back analysis. The simulated settlements show good agreements with the monitoring data, illustrating that the back analysis is reasonable and accurate. Furthermore, the deformation gradient of the dam crest has been analysed. The dam crest has a great possibility of cracking due to the uncoordinated deformation, which agrees well with the field investigation. The deformation gradient decreases to the value lower than the critical one and reaches a stable state after the second full reservoir.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.1
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• pp.53-67
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• 2023

Background: This study comparatively evaluated the effects of equipment-based pilates exercises (EPE) and lumbar stability exercises (LSE) in patients with chronic low back pain in terms of their Visual Analogue Scale(VAS), Oswestry Disability Index(ODI), and abdominal muscle thickness. Methods: A total of 30 participants were recruited and randomly assigned to either the EPE or the LSE. The VAS, ODI, and abdominal muscle thicknesses of the participants were measured before and after the intervention. Results: The EPE were more effective in terms of the duration of a sustained reduction in VAS scores. post hoc test revealed that EPE were more efficacious in terms of a sustained improvement in ODI scores. With respect to changes in abdominal muscle thickness, there was a significant difference in the thickness of internal oblique muscles(IO) and the external oblique muscles(EO) between the two groups. Conclusion: In this study, both types of exercise interventions resulted in improvements in the VAS, ODI scores, and abdominal muscle thickness in patients with chronic low back pain. However, EPE were found to be more effective than LPE in terms of longer sustained improvements in VAS and ODI scores. Also, with respect to abdominal muscle thickness, the thickness of EO and IO improved only in the EPE group.

• Journal of the Korean Wood Science and Technology
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• v.27 no.3
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• pp.99-116
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• 1999

Wooden hollow core flush door is one of the main products of furniture manufacturing and woodworking industries. Warping and buckling of the door is serious problems in service. It has been reported that warping is caused by differences of physical and mechanical properties of face and back of skin panel for the door. This study focused on the prediction of warping and buckling phenomena of the flush door using numerical models. Predictions from the models were also compared with the experimental results obtained from the doors with plywood and hardboard skin panels under various environmental conditions. Three elastic constitutive models, so called elastic beam model, plate model and plate-buckling model, were employed to predict warping and buckling of the doors. It was observed that warping was more pronounced in low humidity condition than in high humidity condition. The plate model considering Poisson's effect was reliable to predict warping more closely than elastic beam model in low humidity condition. The plate-buckling model, however, was the best in the fitting of predictions with the experimental results under high humidity condition because buckling was developed in face and back of skin panel at that condition.

• Journal of Magnetics
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• v.14 no.1
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• pp.47-51
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• 2009

The coreless linear synchronous motor (coreless LSM) has been widely used as a driving source of semiconductor production processes for machine speeding up, positioning accuracy and simple maintenance. However, this coreless LSM suffers the disadvantage of decreased thrust force created by the leakage of magnetic flux. With the goal of increasing the generated thrust force and decreasing the cogging force, the slot of the core part was removed and a moving-coil-type slotless LSM (moving-coil-type slotless LSM) is proposed in this paper. Although this moving-coil-type slotless LSM with a back-yoke at the primary side demonstrated an increase in the generated thrust force, it remained capable of generating the cogging force when the primary side was moved due to the position between the permanent magnet and the back-yoke. Therefore, we attempted to decrease the cogging force of the moving-coil-type slotless LSM. We found that the back-yoke length at the primary side needs to be made $0.5{\tau}$ longer than the integral multiple of the magnetic pole pitch in order to decrease the cogging force created by the moving-coil-type slotless LSM.

• Proceedings of the Korea Contents Association Conference
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• 2010.05a
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• pp.112-114
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• 2010

Mainly through the pervasive emergence of portable devices (laptops, PDAs, now iPods), the screen arts, that is, the cinematic arts has suffered the loss of what constitutes the core of its existence: the theatre and theatre-audience. This paper discusses cinema's distinct place and significance in culture and its difference from television and other forms of mass media. The most pressing question at hand would be, "how do you bring back attention to the medium that is distinctly cinematic?" "How do you bring people back to the theatres?" This paper argues that cinema, and the film industry as a whole must push for a technological leap that is in conjunction with culture. With mentioning of the rapid development of 3D technologies in the moving images, this paper proposes that such technological novelties and innovation are necessary conditions for a new kind of film culture to emerge.

• Korea journal of population studies
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• v.12 no.2
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• pp.56-68
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• 1989

The methodology in historical demography comprises the three core areas the family reconstitution method at the Institut National d' Ftudes Demographiques(I.N.E.D), the back projection at the Cambridge Group for the History of PopuJation and Social Struc-ture(HPSS). and the household-pattern analysis at the Cambridge Group and at the California Institute of Technology. The paper presents an outline of the family reconstitu-tion method and discusses the problems, both theoretical and methodological, arising from the problematic back projection vis-a-vis the usual inverse projection developed by Ronald D. Lee at Berkeley. Recent developments in the tield of the generalized inverse projection method designed 10 supplement the defects in the back projection and the inverse projection are presented. and for ease of explanation of the parish register data for the family reconstitution form (FRE). pre-modern Korean household register data are presented along with the parish register data of England and Wales that constitute the backbone of historical demography in pre-modern Europe. Possibilities of exploring the household pattern analysis method based on the Laslett-Hammel classification scheme for the mid-eighteenth-century Korean household register data are suggested.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.8-13
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• 2009

LED BLU(Back Light Unit), based on MCPCB(Metal Core Printed Circuit Board) with anodizing oxide dielectric layer and improved thermal dissipation property, are presented. Reflecting cups were also formed on the surface of the MCPCB such that optical coupling between neighboring chips were minimized for improving the photon extraction efficiency. LED chips were directly attached on the MCPCB by using the COB (Chip On Board) scheme.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.1
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• pp.16-22
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• 2013

This paper presents the analysis and optimization of air-core permanent magnet linear synchronous motor with overlapping concentrated windings to achieve high thrust density, high thrust per copper losses and low thrust ripple. For the motor design, we adopt equivalent magnetizing current (EMC) method to analyze the magnetic field and give analytical formulae for calculation of motor parameters such as no-load back EMF, dynamic force, thrust density and thrust per copper losses. Further, we proposed a multi-objective optimization by genetic algorithm to search for the optimum parameters. The design optimization is verified by 2-D Finite Element analysis (FEA).

• Transactions of Materials Processing
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• v.26 no.4
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• pp.240-245
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• 2017

Mixed-model production technology is a method of producing multiple products with one production process and production line in order to reduce wasted manpower and adjust to market trends. In other words, mixed-model production is a flexible production system that changes production volume by model according to market demand. This study has developed a progressive laminated stamping die technology to enable flexible production of a motor core consisting of attaching and detaching the Cam on the back of the punch so that two kinds of stator and two kinds of rotor could be produced in one progressive die.