• Computational Structural Engineering
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• v.10 no.4
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• pp.205-216
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• 1997

In order to trace the lateral post-buckling behaviors of thin-wafled space frames, a geometrically nonlinear finite element formulation is presented by applying incremental equilibrium equations based on the updated Lagrangian formulation and introducing Vlasov's assumption. The improved displacement field for symmetric thin-walled cross sections is introduced based on inclusion of second order terms of finite rotations, and the potential energy corresponding to the semitangential rotations and moments is consistently derived. For finite element analysis, tangent stiffness matrices of the thinwalled space frame element with 7 degrees of freedom including the restrained warping for each node are derived by using the Hermition polynomials as shape functions. A co-rotational formulation in order to evaluate the unbalanced loads is presented by separating the rigid body rotations and pure deformations from incremental displacements and evaluating the updated direction cosines of the frame element due to rigid body rotations and incremental member forces from pure deformations. Finite element solutions for the spatial buckling and post-buckling analysis of thin-walled space frames are presented and compared with available solutions and other researcher's results.

• Computational Structural Engineering
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• v.10 no.1
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• pp.201-211
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• 1997

A clearly consistent finite element formulation for geometrically non-linear analysis of space frames is presented by applying incremental equilibrium equations based on the updated Lagrangian formulation and introducing Vlasov's assumption. The improved displacement field for symmetric cross sections is introduced based on inclusion of second order terms of finite rotations, and the potential energy corresponding to the semitangential rotations and moments is consistently derived. For finite element analysis, elastic and geometric stiffness matrices of the space frame element are derived by using the Hermitian polynomials as shape functions. A co-rotational formulation in order to evaluate the unbalanced loads is presented by separating the rigid body rotations and pure deformations from incremental displacements and evaluating the updated direction cosines of the frame element due to rigid body rotations and incremental member forces from pure deformaions. Finite element solutions for the spatial buckling and post-buckling analysis of space frames are compared with available solutions and other researcher's results.

• Journal of the Ergonomics Society of Korea
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• v.28 no.3
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• pp.41-47
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• 2009

The purpose of this study, during the lifting task was researching the difference and a relationship between the ground reaction force and the grip strength by change of position. After grip strength has measured in symmetry position and asymmetry position at 45cm and 75cm of height of hand, ground reaction force was measured by same attitude lifting wooden box. We analyzed the difference of grip strength and ground reaction force in each position change. The results of grip strength, the grip strength of both hand were significant difference that in study subject symmetry and asymmetry position (p<0.01). The results of symmetry lifting task, the study subjects was significant difference of the ground reaction force difference by height (p<0.05). Asymmetry lifting task was significant difference of ground reaction force difference by direction of rotation was changed (p<0.01). The result of it will rotate with non-dominant hand side of lifting tasks from height 75cm where it easily maintains a balance possibility and decreasing the load of the hand. Therefore, from the workshop in the work people, it will be between the height 75cm and non-dominant hand side of trunk rotatory direction in the lifting tasks. Future study is necessary researched about the change of grip strength when the height of the hand is higher, and the difference of the ground reaction force when the change of weight.

• Advanced Composite Materials
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• v.17 no.1
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• pp.57-73
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• 2008

The present paper focuses on experimental verification of the ply-by-ply basis inelastic analysis of multidirectional laminates. First of all, rate dependence of the tensile behavior of balanced symmetric cross-ply T800H/epoxy laminates with a $[0/90]_{3S}$ lay-up under off-axis loading conditions at $100^{\circ}C$ is examined. Uniaxial tension tests are performed on plain coupon specimens with various fiber orientations $[{\theta}/(90-{\theta})]_{3S}$ ($\theta$ = 0, 5, 15, 45 and $90^{\circ}C$) at two different strain rates (1.0 and 0.01%/min). The off-axis stress.strain curves exhibit marked nonlinearity for all the off-axis fiber orientations except for the on-axis fiber orientations $\theta$ = 0 and $90^{\circ}$, regardless of the strain rates. Strain rate has significant influences not only on the off-axis flow stress in the regime of nonlinear response but also on the apparent off-axis elastic modulus in the regime of initial linear response. A macromechanical constitutive model based on a ply viscoplasticity model and the classical laminated plate theory is applied to predictions of the rate-dependent off-axis nonlinear behavior of the cross-ply CFRP laminate. The material constants involved by the ply viscoplasticity model are identified on the basis of the experimental results on the unidirectional laminate of the same carbon/epoxy system. It is demonstrated that good agreements between the predicted and observed results are obtained by taking account of the fiber rotation induced by deformation as well as the rate dependence of the initial Young's moduli.

• Journal of Chest Surgery
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• v.36 no.3
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• pp.164-174
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• 2003

Background: The Nuss procedure is a recently developed technique for minimally invasive repair of pectus excavatum using a metal bar. Although its technical simplicity and cosmetic advantages are remarkable, applications have been limited to children with standard pectus excavatum. We report a single center experience of the technique that has been evolving in order to correct asymmetric pectus configurations and adult patients. Material and Method: Between August 1999 and June 2002, 322 consecutive patients un-derwent repair by the Nuss technique and its modifications. Among them, 71 (22%) were adults. For the precise correction, morphology of the pectus was classified as symmetric and asymmetric types. Asymmetric type was subdivided into eccentric and unbalanced types. In repair, differently shaped bars were applied to individual types of pectus to achieve symmetric correction. Result: Symmetric type was 57.5% (185/322) and asymmetric type was 42.5% (137/322). Eccentric, unbalanced, and combined types were 71, 47 and 19, respectively, Major modifications were bar shaping and fixation. In asymmetric group, different shapes of asymmetric bars were applied (n=125, 38.8%). For adult patients, double bar or compound bar technique was used (n=51, 15.8%). To prevent bar rotation, multipoint wire fixations to ribs were used. Major postoperative complications were pneumothorax (n=24, 7.5%) and bar displacement (n=11, 3.4%). 42 patients had bar removal 2 years after the initial procedure. Conclusion: The Nuss procedure is safe and effective. Modifications of the techniques in accordance with precise morphological classification enabled the correction of all variety of pectus excavatum including asymmetric types and adult patients.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.133-133
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• 2002

Purpose： The purpose of paper is to implement software to visualize brain fiber tract using a 24-bit color coding scheme and to test its feasibility. Materials and Methods： MR imaging was performed on GE 1.5 T Signa scanner. For diffusion tensor image, we used a single shot spin-echo EPI sequence with 7 non-colinear pulsed-field gradient directions： (x, y, z)：(1,1,0),(-1,1,0),(1,0,1),(-1,0,1),(0,1,1),(0,1,-1) and without diffusion gradient. B-factor was 500 sec/$\textrm{mm}^2$. Acquisition parameters are as follows： TUTE=10000ms/99ms, FOV=240mm, matrix=128${\times}$128, slice thickness/gap=6mm/0mm, total slice number=30. Subjects consisted of 10 normal young volunteers (age：21∼26 yrs, 5 men, 5 women). All DTI images were smoothed with Gaussian kernel with the FWHM of 2 pixels. Color coding schemes for visualization of directional information was as follows. HSV(Hue, Saturation, Value) color system is appropriate for assigning RGB(Red, Green, and Blue) value for every different directions because of its volumetric directional expression. Each of HSV are assigned due to (r,$\theta$,${\Phi}$) in spherical coordinate. HSV calculated by this way can be transformed into RGB color system by general HSV to RGB conversion formula. Symmetry schemes： It is natural to code the antipodal direction to be same color(antipodal symmetry). So even with no symmetry scheme, the antipodal symmetry must be included. With no symmetry scheme, we can assign every different colors for every different orientation.(H =${\Phi}$, S=2$\theta$/$\pi$, V=λw, where λw is anisotropy). But that may assign very discontinuous color even between adjacent yokels. On the other hand, Full symmetry or absolute value scheme includes symmetry for 180$^{\circ}$ rotation about xy-plane of color coordinate (rotational symmetry) and for both hemisphere (mirror symmetry). In absolute value scheme, each of RGB value can be expressed as follows. R=λw｜Vx｜, G=λw｜Vy｜, B=λw｜Vz｜, where (Vx, Vy, Vz) is eigenvector corresponding to the largest eigenvalue of diffusion tensor. With applying full symmetry or absolute value scheme, we can get more continuous color coding at the expense of coding same color for symmetric direction. For better visualization of fiber tract directions, Gamma and brightness correction had done. All of these implementations were done on the IDL 5.4 platform.

• Journal of Korea Entertainment Industry Association
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• v.15 no.1
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• pp.171-180
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• 2021

The present study investigated the effects of dynamic tubing gait (DTG II) program on the balancing ability for the promotion of life care of patients with chronic stroke. In the study, 25 sessions of DTG II program (30 minutes per session, 5 sessions per week, for a total of 5 weeks) were applied to 10 patients with chronic stroke. To determine the effects of DTG II program for improving balance, surface electromyography(external oblique, erector spinae, iliopsoas, gluteus maximus), symmetry index test on three pelvic axes, and dynamic gait index test were performed before and after the intervention. The results showed statistically significant differences between preand post-intervention measurements of the gluteus maximus muscle at early and mid-stance phases(p<.05). The pelvic symmetry index differed significantly between pre- and post-intervention measurements of diagonal and rotational movement(p<.05). Comparison of dynamic gait index also showed statistically significant differences between pre- and post-intervention measurements(p<.05). Based on these findings, it was determined that the DTG II program was able to improve the balancing ability of patients with chronic stroke by activating their trunk muscles and improving the symmetry of diagonal pelvic movement and rotation. Therefore, DTG II program is recommended as an interventional method to improve life-care through improving the balancing ability of patients with chronic stroke.