• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.7
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• pp.555-561
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• 2003

An iterative modal analysis approach is developed to determine the effect of transverse open cracks on the dynamic behavior of simply supported Euler-Bernoulli beams with the moving masses. The influences of the velocities of moving masses, the distance between the moving masses and a crack have been studied on the dynamic behavior of a simply supported beam system by numerical method. The Presence of crack results In large deflection of beam. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments i.e. the crack is modelled as a rotational spring. This flexibility matrix defines the relationship between the displacements and forces across the crack section and is derived by applying fundamental fracture mechanics theory. Totally, as the velocity of the moving masses and the distance between the moving masses are increased, the mid-span deflection of simply supported beam with the crack is decreased.

• The Journal of Industrial Distribution & Business
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• v.11 no.5
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• pp.7-16
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• 2020

Purpose: Prior studies empirically examine how financial flexibility is related to required returns by using realized returns and considering cash holdings as net debts, but they fail to find consistent results. Conjecturing that inappropriate proxy of required returns and aggregation of cash and debts caused the inconsistent results, this study revisits this topic by using a refined proxy of required returns and separating cash holdings from debts. Research design, data and methodology: This study uses a multivariate regression model to investigate the relationship between required returns on cash holdings and financial leverage. The required returns are estimated using the return decomposition method by vector autoregression model. Empirical tests use US stock market data from1968 to 2011. Results: Empirical results reveal that both cash holdings and leverage are positively related to required returns. The positive relation is stronger in economic downturns than in economic upturns. Conclusions: Three major findings are drawn. First, risky firms prefer large cash balance. Second, information shocks in the realized returns caused failure of prior studies to find consistent positive relationship between leverage and realized returns. Third, cash and leverage are related to required returns in the same direction; therefore, cash cannot be considered as negative debts.

• The Journal of Korean Physical Therapy
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• v.23 no.3
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• pp.57-63
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• 2011

Purpose: The purposes of this study were to investigate the effectiveness of Pilates exercise on Fitness Factors related to motor performance including flexibility, agility, power, balance, and muscle endurance. Methods: Forty subjects were randomly allocated to one of two groups. The Pilates group did Pilates exercises 3 times a week for 8weeks, 60 minutes each time, and submitted to evaluation of protocols to assess sitting and reaching tests, a standing broad jump test, a side step test, a balance test using a Biodex Stability System, and muscle endurance using CSMI. Results: The Pilates group (n=20) participated in Pilates exercises three times in a week for eight weeks. The results show significant post-test differences in the Pilates group in the following areas: flexibility, agility, power, balance and muscle endurance. There was no significant increase in the control group. Post-exercise, there was no significant difference between the Pilates and control group. Conclusion: The Pilates method can offer significant improvement in personal flexibility, agility, power, balance, and muscle endurance. This study suggests that individuals can improve their Fitness Factors related to motor performance using Pilates exercises that do not require equipment or a high degree of skill. Further study is required to quantify the benefits of Pilates exercise.

• Structural Engineering and Mechanics
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• v.44 no.3
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• pp.339-361
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• 2012

Large amplitude free vibration and thermal post-buckling of shear flexible Functionally Graded Material (FGM) beams is studied using finite element formulation based on first order Timoshenko beam theory. Classical boundary conditions are considered. The ends are assumed to be axially immovable. The von-Karman type strain-displacement relations are used to account for geometric non-linearity. For all the boundary conditions considered, hardening type of non-linearity is observed. For large amplitude vibration of FGM beams, a comprehensive study has been carried out with various lengths to height ratios, maximum lateral amplitude to radius of gyration ratios, volume fraction exponents and boundary conditions. It is observed that, for FGM beams, the non-linear frequencies are dependent on the sign of the vibration amplitudes. For thermal post-buckling of FGM beams, the effect of shear flexibility on the structural response is discussed in detail for different volume fraction exponents, length to height ratios and boundary conditions. The effect of shear flexibility is observed to be predominant for clamped beam as compared to simply supported beam.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.651-656
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• 2007

Changes in measured structural responses induced by a damage could be significantly smaller than those by environmental effects such as temperature and temperature gradients. It is highly desirable to develop a methodology to distinguish the changes due to the structural damage from those by the environmental variations. In this study, a novel method to extract the damage-induced deflection under temperature variations is presented using the outlier analysis on the deflections obtained using the modal flexibility matrices. The main idea is that temperature change in a bridge would produce global increase or decrease in deflections over the whole bridge while structural damages may cause local variations in deflections near the damage locations. Hence, the correlation between the deflection measurements may show high abnormality near the damage locations. A series of laboratory tests were carried out on a bridge model with a steel box-girder for 14 days. It has been found that the damage existence assessment and localization can carried out for a case with relatively small damage under the temperature variations

• Journal of muscle and joint health
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• v.14 no.1
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• pp.42-51
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• 2007

Purpose: The purpose of this study was to examine the effects of Tai-Chi self-help program for osteoarthritis patients. Method: This study was performed from 1th August. to 30th Dec. 2006. 27 osteoarthritis patients were participated in the Tai-Chi self-help program. Outcome measures were pain, flexibility and balance, self-efficacy. Data were analysed by SPSS WIN 12.0. Result: There were statistically significant in balance and knee flexibility. but no significant differences were found in pain and self-efficacy. Conclusion: In conclusion, Tai-Chi self-help program was proved to be an effective nursing intervention to increase the balance and flexibility. Also 12 forms of Tai-Chi self-help program has been found safely applicable to the patients with osteoarthritis for 8 weeks. A rigorous research design should be further considered to identify the long-term benefit for this population.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1085-1090
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• 2003

An iterative modal analysis approach is developed to determine the effect of transverse open cracks on the dynamic behavior of simply supported Euler-Bernoulli beams with the moving masses. The influences of the velocities of moving masses, the distance between the moving masses and a crack have been studied on the dynamic behavior or a simply supported beam system by numerical method. no presence or crack results in large deflection of beam. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments i.e. the crack is modelled as a rotational spring. This flexibility matrix defines the relationship between the displacements and forces across the crack section and is derived by applying fundamental fracture mechanics theory. Totally, as the velocity of the moving masses and the distance between the moving masses are increased, the mid-span deflection of simply supported beam with the crack is decreased.

• Structural Engineering and Mechanics
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• v.38 no.3
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• pp.361-384
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• 2011

Earlier studies on hollow-circular rubber bearings, all of which are conducted for steel-reinforced bearings, indicate that the hole presence not only decreases the compression modulus of the bearing but also increases the maximum shear strain developing in the bearing due to compression, both of which are basic design parameters also for fiber-reinforced rubber bearings. This paper presents analytical solutions to the compression problem of hollow-circular fiber-reinforced rubber bearings. The problem is handled using the most-recent formulation of the "pressure method". The analytical solutions are, then, used to investigate the effects of reinforcement flexibility and hole presence on bearing's compression modulus and maximum shear strain in the bearing in view of four key parameters: (i) reinforcement extensibility, (ii) hole size, (iii) bearing's shape factor and (iv) rubber compressibility. It is shown that the compression stiffness of a hollow-circular fiber-reinforced bearing may decrease considerably as reinforcement flexibility and/or hole size increases particularly if the shape factor of the bearing is high and rubber compressibility is not negligible. Numerical studies also show that the existence of even a very small hole can increase the maximum shear strain in the bearing significantly, which has to be considered in the design of such annular bearings.

• Steel and Composite Structures
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• v.24 no.4
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• pp.425-439
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• 2017

As a thin-walled structure, local joint flexibility (LJF) in a tubular structure is prominent, and it may produce significant effect on the static performance for the overall structure. This study presents a simplified analytical model to analyze the static behavior for a steel tubular structure with LJF. The presented model simplifies a tubular structure into a frame model consisted of beam elements with considering the LJFs at the connections between any two elements. Theoretical equations of the simplified analytical model are deduced. Through comparison with 3-D finite element results of two typical planar tubular structures consisted of T- and Y-joints respectively, the presented method is proved to be accurate. Furthermore, the effect of LJF on the overall performance of the two tubular structures (including the deflection and the internal forces) is also investigated, and it is found from analyses of internal forces and deformation that a rigid connection assumption in a frame model by using beam elements in finite element analysis can provide unsafe and inaccurate estimation.

• PNF and Movement
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• v.16 no.3
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• pp.345-353
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• 2018

Purpose: The purpose of the present study was to compare the effects of proprioceptive neuromuscular facilitation (PNF) and static stretching on weight distribution and flexibility for trunk flexion. Method: Sixty participants who had no musculoskeletal disorders were recruited from a local university within six months of this study. The participants were randomly assigned to a PNF stretching group (N=30) and a static stretching group (N=32). For the pre-and post-measurement design, the left-right weight distribution, anterior-posterior weight distribution, and finger-to-floor distance (FFD) were measured before and after the stretching interventions. Result: The FFD results were significantly improved after the interventions, regardless of the group differentiation (p<0.05). The PNF stretching intervention significantly increased the differences between anterior and posterior weight distribution compared to the static stretching group (p<0.05). Conclusions: Both the PNF and static stretching interventions could improve flexibility for trunk flexion mobility. Although the PNF intervention improved the weight distribution in the anterior-posterior direction, further research is required to investigate the various PNF interventions on left-and-right and anterior-posterior weight distribution.