• Journal of the Korean Crystal Growth and Crystal Technology
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• 제23권2호
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• pp.67-75
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• 2013

In order to improve osseo-integration of a dental implant with bone crystal we studied an implant with holes inside its body to deliver bioactive materials based on a proposed patent. After bioactive material is absorbed, bone crystal can grow into holes to increase implant bonding in addition to surface integration. The larger cross section area of outlet holes showed the less values of the maximum stress, and the stress concentrations near the uppermost outlet holes were also reduced with an increasing number of outlet holes. The conclusion, that the uppermost outlet design improvement was most effective to reduce the stress concentration and improve the growth rate of bone crystal, could be drawn. After the design optimizations, Type 6-C had provided the best results in this study. The overall shape optimization studies on the shape, location, number, and so on, of the outlet holes, should be carried out further.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.11-17
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• 2000

,An residual stress and out-of plane deformation produced by butt welding was analyzed by four kinds of 3D-FEM programs(Thermal El-P1 Analysis) developed by authors. The magnitude of deformation of perpendicular to the welding line generated by butt welding was large when the reduced integration method was used. This was because of removal of the locking phenomenon, which it was generally known that the stiffness of the shear component of out-of-plane was largely evaluated. And the magnitude of residual stress was analyzed by using the FEM program based on a large and small deformation theory was similar to that was analyzed by the redeced integration method.

• The Journal of Korean Academy of Sensory Integration
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• 제3권1호
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• pp.37-47
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• 2005

Objective : This study was to find out whether there was a difference between parenting stress of parents with and without sensory defensiveness and level of the quality of life, to analyze the factors related with parenting stress of parents and quality of life and to develop intervention program to improve quality of life of parents that care children with problem on sensory process. Methods : The population of this study was consisted of 82 children aged from 3 to 7 years and was treated occupational therapy in clinics or welfare centers for disabled persons. Parenting stress was assessed with Parenting Stress Index and the quality of life scales used by Lee Jeong-Eun was used to assess the level of quality of life. Result : The difference between parenting stress with and without sensory defensiveness and level of quality of life was only shown in parenting stress, and the correlation between parenting stress with and without sensory defensiveness and quality of life indicated negative correlation in both sensory defensiveness and no sensory defensiveness group(r=-0.52, r=-0.65, p<0.05). This study found there was significant difference between quality of life factors affecting parenting stress of parents and parenting stress factors affecting quality of life in sensory defensiveness and no sensory defensiveness group. Conclusion : The study showed that clinicians must develop appropriative intervention program with sensory defensiveness or without sensory defensiveness for decreasing parenting stress and increasing quality of life for their parents.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제23권2호
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• pp.76-80
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• 2013

For further improvement of osseo-integration of bone crystal with a dental implant, a design optimization study is carried out for various holes inside its body to deliver bioactive materials and the effect of bioactive material injection on the bone crystal growing. When bioactive material is absorbed, the bone crystal can grow into holes, which would increase the strength of implant bonding as well as a surface integration. The stress concentrations near the uppermost outlet holes were reduced with increasing the number of outlet holes. A design improvement in the uppermost outlet was shown to be effective in reducing the stress concentration. For design parameters under consideration in this study, total area of outlet of 6.38 $mm^2$ and maximum stress of 1.114 MPa, which corresponds to type 6-C. It is due to the minimization of maximum stress and total area of outlet. The design of the outlet facing down was more effective in reducing the maximum stress value compared with a horizontal symmetry.

• Structural Engineering and Mechanics
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• 제91권5호
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• pp.527-538
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• 2024

The standard numerical approximation of structural displacement field leads to the thickness-wise transverse shear stress distributions which are quite different from the exact ones. To overcome this inherent problem, an effective and reliable post-processing method is presented based on the strain recovery and the stress equilibrium, particularly for functionally graded cylindrical and conical elastic panels. The present method is developed in the framework of locking-free 2-D natural element method. Through the recovery of displacement component-wise derivatives, the element-wise discontinuous in-plane strain distributions are enhanced to be globally continuous and smoothened. And, using the continuous in-plane strains, the troublesome poor transverse shear stress distributions are enhanced through the thickness-wise integration of static equilibrium equations. The validity of present post-processing method is verified through the comparison with the reference solutions. In addition, the comparative experiments are also performed to investigate the difference between the present method and other available post-processing methods. The numerical results confirm that the present method provides the accurate transverse shear stress distributions which are consistent with the reference solutions and much better than other available methods.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제20권12호
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• pp.3792-3803
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• 1996

Since the skew beam element has two curvatures which are a curvature and a torsion, spatial behavior of curved beam which cannot be included in one plane can be anlayzed by emploting the skew beam element. The $C^{0}$-continuous skew beam element shows the stiffness locking phenomenon when full integration is employed. The locking phenomenpn is characterized by two typical phenomena ; one is the much smaller displacement thant the exact one and theother is the undelation phenomenon is stress distribution. In this paper, we examine how unmatched coefficient in the constrained energy brings about the locking by Reduced Minimization theory. We perform the numerical ones. These comparisons show that uniformly full integration(UFI), which employs full integration for the constrained energy, entails the locking phenomenon. But the use of uniformly reduced integration(URI) of selectively reduced integration(SRI), which employs reduced integration for constrained energy, does not produce the significant errors of displacements of the undulation phenomenon in stress distribution since they do not entails the locking, Additionally, the error due to the approximated parameters for describing the geometry of skew beam is examined.d.

• Korean Journal of Social Welfare
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• 제67권3호
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• pp.57-82
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• 2015

This study examines the extent to which community cohesion moderates the effects of neighborhood disorder on community integration among persons with mental illnesses(MI) who are living in the community. Stress process model, social disorganization theory, and neighborhood disorder model were considered with regard to the moderating effect of community cohesion. 692 persons with MI who utilized Community Mental Health Enhancement Centers were surveyed and analyzed, employing moderated regression model. Major findings showed that neighborhood disorder increased social integration. Community cohesion moderated the relationships of neighborhood disorder to three dimensions of community integration: physical, social and psychological integration. Implications for community intervention beyond the individual and service-level interventions were addressed in order to accomplish community integration for persons with MI.

• Journal of the Korean Geotechnical Society
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• 제19권4호
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• pp.277-286
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• 2003

A constitutive equation was implemented in order to model the behavior in overall ranges from small to large strains, which is based on anisotropic hardening rule and total stress concept. The constitutive model was implemented in ABAQUS code in which large deformation analysis can be performed accurately and efficiently. The formulation includes (1) finite strain plasticity on the basis of Jaumann stress rate, (2) implicit stress integration and (3) consistent tangent moduli. A large deformation analysis was performed with the constitutive model using ABAQUS program. In the analysis of an actual embankment, it was found that the proposed model was formulated accurately and efficiently.

• The Journal of Korean Academy of Sensory Integration
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• 제5권1호
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• pp.1-20
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• 2007

Objective : The purposes of this study were two-fold; First it investigated self-esteem, stress and coping behaviors of mothers with handicapped children as a function of their and their children's characteristics; Second it examined the relationship among these variables. Method : The subjects were 294 mothers of handicapped children who were receiving treatment in one of the sixteen special therapy institutions in Seoul, Gyeonggi-do, and Gangwon-do. Rosenberg's(1965) Self-Esteem Scale translated by Jeon Byung-Jea(1974) was used to measure the degree of mothers' self-esteem. Mothers' stress was assessed using the Support Burden Scale revised by Seong Jong-sook(2000) and their coping behavior was examined using Folkman's(1986) Coping Scale translated by Jeon Sung-hye. The data were analyzed with descriptive statistics, t-test, one-way ANOVA and Pearson's Correlation. Result : The major results of this study were as follows; First, working mothers of handicapped children showed higher self-esteem and problem solving coping behavior more than non-working mothers. Self-esteem was found higher with high-income mothers than with low-income ones. Stress was shown more intense to low- and middle-income mothers than to high-income ones. Problem solving coping behavior was preferred more by high-and middle-income mothers than by low-income ones. Second, mothers with the mild-handicap children showed higher self-esteem than those with the first-degree handicap ones. Mothers of children with first-, second- and third-degree handicap perceived more stress than those with mild handicap. Coping behavior was significantly different depending on the severity of children's handicap, but no significant difference was found among the groups. Third, the higher the self-esteem of mothers was, the less they perceived stress and used more of problem solving coping behavior. When mothers perceived a great deal of stress, they used more of emotion-oriented coping behaviors.

• Journal of the Korean Society for Precision Engineering
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• 제16권4호통권97호
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• pp.197-204
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• 1999

The boundary element method was used for studying singularities of an interface crack with contact zones. The iterative procedure is applied to estimate the contact zone size. Because the contact zone size was extremely small in a tension field, a large number of Gaussian points were used for numerical integration of the Kernels. Stress extrapolation method and J-integral were used ofr determining stress intensity factors. When the interface crack was assumed to have opened tips, oscillatory singularities appear near the tips of the interface crack. But the interface crack with contact zone which Comninou suggested had no oscillatory behavior. The contact zone size under shear loading was much larger than that under tensile. The stress intensity factors computed by stress extrapolation method were close to those of Comninou's solution. And the stress intensity factor evaluated by J-integral was similar to that by stress extrapolation method.