• Journal of Society of Preventive Korean Medicine
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• v.12 no.2
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• pp.85-100
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• 2008

The purpose of this study was to determine factors influencing family closeness in family with an elderly members. The study was conducted with 1,904 subjects during 3 months from 1st March to 30,May. 2006. The results were as follows. 1. Family closeness of subjects was significantly associated with age, sex, marital status, monthly allowance, education level, occupation, the number of family members living together, health state, stress, and emotional conflict with children. 2. Emotional conflict with children was significantly associated with age, sex, religion, the number of family members living together, occupation, health state, stress, family closeness. 3. Stress was significantly associated with age, sex, religion, the number of family members living together, occupation, stress, family closeness. Finaly, Family closeness in family with an elderly member was positively related to family type(living with a spouse), monthly allowance, occupation but negatively related to emotional conflict with children and stress levels. The government, social service units and experts need to pay more attention to factors influencing family closeness and devise effective policy and programs for healthier family relations.

• Journal of the Korean Society of Safety
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• v.14 no.1
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• pp.19-24
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• 1999

A two dimensional thermo elasto-plastic finite clement stress analysis was performed to study stress distributions in functionally gradient material. The upper $ZrO_2$ surface is heated at 1200K until a steady state is established and cooled at 300K. The influences on the thermal stress distributions due to the difference of compositional gradient exponent p were investigated. In this study, we obtained the thermal stresses are low for p=1.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.667-670
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• 2004

This study describes a practical method of measurement of the sustained stress in concrete structures. In most cases, the sustained stress was determined by various theoretical calculations. However, the theoretical calculations can not always provide sufficient informations about current stress state having lots of uncertainty. Therefore, the present study proposes a practical measuring method, Partial Sectioning Method.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.749-754
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• 1998

This study describes a practical method for the measurement of sustained stress in concrete structures. In most cases, the sustained stress was determined by various theoretical calculation. However, the theoretical calculation can not always provide a sufficient information on the current stress state due to lots of uncertainty. Therefore, the present study proposes a practical in situ measuring method, Partial Sectioning Method

• Korean Journal of Materials Research
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• v.33 no.5
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• pp.205-213
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• 2023

This paper reports the results of an experimental examination using X-rays to test annealing materials for lapped bearing steel (STB2), to confirm the validity of the weighted averaging analysis method. The distribution behavior for the α_𝜓-sin²𝜓 diagram and the presence or absence of differences in the peak method, half-value breadth method, and centroid method were investigated. When lapping the annealed bearing steel (STB2) material, a residual stress state with a non-directional steep gradient appeared in the surface layer, and it was found that the weighted averaging analysis method was effective. If there is a steep stress gradient, the sin²𝜓 diagram is curved and the diffraction intensity distribution curve becomes asymmetric, resulting in a difference between the peak method, half-value breadth method, and centroid method. This phenomenon was evident when the stress gradient was more than 2~3 kg/mm²/㎛. In this case, if the position of the diffraction line is determined using the centroid method and the weighted averaging analysis method is applied, the stress value on the surface and the stress gradient under the surface can be obtained more accurately. When the stress gradient becomes a problem, since the curvature of the sin²𝜓 diagram appears clearly in the region of sin²𝜓 > 0.5, it is necessary to increase the inclination angle 𝜓 as much as possible. In the case of a lapping layer, a more accurate value can be obtained by considering 𝜎₃ in the weighted averaging analysis method. In an isotropic biaxial residual stress state, the presence or absence of 𝜎₃ can be determined as the presence or absence of strain for sin²𝜓≈0.4.

• Structural Engineering and Mechanics
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• v.41 no.4
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• pp.495-508
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• 2012

The strength theory of concrete is significant to structure design and nonlinear finite element analysis of concrete structures because concrete utilized in engineering is usually subject to the action of multi-axial stress. Experimental results have revealed that lightweight aggregate (LWA) concrete exhibits plastic flow plateau under high compressive stress and most of the lightweight aggregates are crushed at this stage. For the purpose of safety, therefore, in the practical application the strength of LWA concrete at the plastic flow plateau stage should be regarded as the ultimate strength under multi-axial compressive stress state. With consideration of the strength criterion, the ultimate strength surface of LWA concrete under multi-axial stress intersects with the hydrostatic stress axis at two different points, which is completely different from that of the normal weight concrete as that the ultimate strength surface is open-ended. As a result, the strength criteria aimed at normal weight concrete do not fit LWA concrete. In the present paper, a multi-axial strength criterion for LWA concrete is proposed based on the Unified Twin-Shear Strength (UTSS) theory developed by Prof Yu (Yu et al. 1992), which takes into account the above strength characteristics of LWA under high compressive stress level. In this strength criterion model, the tensile and compressive meridians as well as the ultimate strength envelopes in deviatoric plane under different hydrostatic stress are established just in terms of a few characteristic stress states, i.e., the uniaxial tensile strength $f_t$, the uniaxial compressive strength $f_c$, and the equibiaxial compressive $f_{bc}$. The developed model was confirmed to agree well with experimental data under different stress ratios of LWA concrete.

• Advances in Computational Design
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• v.5 no.3
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• pp.305-321
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• 2020

In this paper is presented the solution method for three-dimensional problem of transversely isotropic body's elastoplastic deformation by the finite element method (FEM). The process of problem solution consists of: determining the effective parameters of a transversely isotropic medium; construction of the finite element mesh of the body configuration, including the determination of the local minimum value of the tape width of non-zero coefficients of equation systems by using of front method; constructing of the stiffness matrix coefficients and load vector node components of the equation for an individual finite element's state according to the theory of small elastoplastic deformations for a transversely isotropic medium; the formation of a resolving symmetric-tape system of equations by summing of all state equations coefficients summing of all finite elements; solution of the system of symmetric-tape equations systems by means of the square root method; calculation of the body's elastoplastic stress-strain state by performing the iterative process of the initial stress method. For each problem solution stage, effective computational algorithms have been developed that reduce computational operations number by modifying existing solution methods and taking into account the matrix coefficients structure. As an example it is given, the problem solution of fibrous composite straining in the form of a rectangle with a system of circular holes.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.221-230
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• 2011

The purpose of this study was to determine whether parenting stress is related to anxiety in children with ADHD. The data were provided by 112 children between the ages of 7 and 9. Forty nine children with a diagnosis of ADHD were recruited through 3 departments of child psychiatry and 63 normal children were recruited from elementary schools from the same city. The Korean version of Parenting Stress Index-Short Form was used to assess parenting stress and the Korean version of the State Trait Anxiety Inventory for Children was used to assess the level of anxiety. The results show that children with ADHD have significantly higher levels of anxiety and parenting stress than normal children. However, no significant differences in parenting stress and anxiety were found across gender, age, and the type of ADHD. Significant correlation was found between trait anxiety and parental distress and between state anxiety and difficult child. Parenting stress didn't significantly influence on anxiety in children with ADHD. Occupational therapist need to consider that the anxiety level of children with ADHD is different from normal children. It is needed for interventions for children with anxiety symptoms and also consultation and intervention for parents with parenting stress.

• Journal of the Korea Safety Management & Science
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• v.7 no.3
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• pp.73-84
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• 2005

This study examined the associations between job stress and psychosocial stress in telecommunication service workers. In this survey, four hundred seventy workers and six variables(general characteristics, state of health, job characteristics, personality, psychosocial characteristics, and job stress) were used to measure worker's subjective satisfaction and status of stress. The results of this study indicated that 135 workers($28\%$) were classified into a high risk group to stress, 317 workers($67\%$) were into a potential risk group, and only 18 workers($6\%$) were into a healthy group. Also the results indicated that job stress outcomes related to job characteristics, personality, and psychosocial characteristics.

• Smart Structures and Systems
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• v.30 no.3
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• pp.245-253
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• 2022

A two-layer beam consisting of an elastoplastic layer and a functional layer made of shape memory alloy (SMA) TiNi is considered. Constitutive relations for SMA are set by a microstructural model capable to calculate strain increment produced by arbitrary increments of stress and temperature. This model exploits the approximation of small strains. The equations to calculate the variations of the strain and the internal variables are based on the experimentally registered temperature kinetics of the martensitic transformations with an account of the crystallographic features of the transformation and the laws of equilibrium thermodynamics. Stress and phase distributions over the beam height are calculated by steps, by solving on each step the boundary-value problem for given increments of the bending moment (or curvature) and the tensile force (or relative elongation). Simplifying Bernoulli's hypotheses are applied. The temperature is considered homogeneous. The first stage of the numerical experiment is modeling of preliminary deformation of the beam by bending or stretching at a temperature corresponding to the martensitic state of the SMA layer. The second stage simulates heating and subsequent cooling across the temperature interval of the martensitic transformation. The curvature variation depends both on the total thickness of the beam and on the ratio of the layer's thicknesses.