• Journal of Korean Biological Nursing Science
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• v.4 no.2
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• pp.79-92
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• 2002

This study was aimed to analyze the variables measuring stress and immune responses, to identify the relationship between stress and immune responses, and to find out the effect of nursing interventions associated with stress and immune responses by reviewing thirty-four published articles since 1970 in Korea. The articles were selected in the field of nursing, stress management, and masters or doctoral dissertations and limited to human subject. Among these, the thirty-one articles were published since 1996 and mainly distributed in nursing (44.1%) and medicine(44.1%). The prevailing research design was nonequivalent control pre-post experimental design(41.1%). The research subjects were 55.9% for patients and 44.1% for healthy general persons including 20.6% of university students. To evaluate stress, both physiologic and psychosocial measures were adapted together in 35.3% of the articles. The most frequent two variables measuring stress and immune response were cortisol level(15.9%) and number or activity of natural killer cell(25.9%). The relation between stress and immune responses was positive in 4 articles, negative in 9 cases, and none in 12 cases. Decreased stress and enhanced immune function have been found when massage, abdominal breathing, exercise, relaxation, and touch were provided as nursing interventions. The articles to investigate the relationship between stress and immune function were limited and the tested variables were diverse. Also there was no consistent evidence to correlate the stress and immune function at present. Further studies are needed to construct a valid research design and to investigate the relationship between stress and immune responses. Nursing interventions to decrease stress should be developed to result in the increased immune function and the effect of these interventions would be verified.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.4
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• pp.703-713
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• 2001

Mechanical joints such as bolted or riveted joints are widely used in structural components and the reliable determination of the stress intensity factors for corner cracks in mechanical joints is needed to evaluate the safety and fatigue life. This paper analyzes the mixed-mode stress intensity factors of surface and deepest points for quarter elliptical corner cracks in mechanical joints by weight function method and the coefficients included in weight function are determined by finite element analyses for reference loadings. The extended form of the weight function method for two-dimensional mixed-mode to three-dimensional is presented and the number of terms in weight function is determined by comparing the results for the different number of terms. The amount of clearance is an important factor in evaluating the severity of elliptical corner cracks in mechanical joints and even horizontal crack normal to the applied load is under mixed-mode in the case that clearance exists.

• Research in Community and Public Health Nursing
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• v.20 no.2
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• pp.215-224
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• 2009

Purpose: This study was performed to examine parenting attitude and stress according to personality type in elementary school students' mothers. Methods: The subjects consisted of 206 mothers of students. The measurement instrument was the questionnaire consisting of Korean-version MBTI and PSI test. Data was collected from March 15th to April 15th, 2008. Results: Among personality types by function, ST type was most, occupying 60.2%. Among personality types by temperament, SJ type was most, occupying 59.2%. The score of affective attitude was highest among the parenting attitudes. Parenting attitude was significantly different according to age, education, economic status, number of children, planned pregnancy, factor of stress, and family type. Parenting stress was significantly different according to planned pregnancy and factor of stress. In parenting attitudes by personality types, affective attitude was significantly different. Parenting stress was significantly different according to personality type by function. There was a negative correlation between affective and autonomic attitudes and parenting stress. There was a positive correlation between rejective attitude and parenting stress. Conclusion: It would be essential to provide dynamic developmental programs for increasing the children's social ability, and nursing intervention, education and counseling programs for decreasing parenting stress through understanding mothers' personality type.

• Advances in Computational Design
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• v.9 no.1
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• pp.39-52
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• 2024

If the governing differential equation arising from engineering problems is treated as an analytic, continuous and derivable function, it can be expanded by one point as a series of finite numbers. For the function to be zero for each value of its domain, the coefficients of each term of the same power must be zero. This results in a recursive relationship which, after applying the natural conditions or the boundary conditions, makes it possible to obtain the values of the derivatives of the function with acceptable accuracy. The elastoplastic analysis of an inhomogeneous thick sphere of metallic materials with linear variation of the modulus of elasticity, yield stress and Poisson's ratio as a function of radius subjected to internal pressure is presented. The Beltrami-Michell equation is established by combining equilibrium, compatibility and constitutive equations. Assuming axisymmetric conditions, the spherical coordinate parameters can be used as principal stress axes. Since there is no analytical solution, the natural boundary conditions are applied and the governing equations are solved using a proposed new method. The maximum effective stress of the von Mises yield criterion occurs at the inner surface; therefore, the negative sign of the linear yield stress gradation parameter should be considered to calculate the optimal yield pressure. The numerical examples are performed and the plots of the numerical results are presented. The validation of the numerical results is observed by modeling the elastoplastic heterogeneous thick sphere as a pressurized multilayer composite reservoir in Abaqus software. The subroutine USDFLD was additionally written to model the continuous gradation of the material.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.1
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• pp.1-9
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• 2009

This paper presents stress distribution around a central crack tip in a tensile plate using phase-shifting photoelasticity and a power series stress function. Isochromatic data along the straight lines far from the crack tip were obtained by phase shifting photoelasticity and were used as input data of the hybrid experimental analysis. By using the complex-type power series stress equations, the photoelastic stress distribution fields in the vicinity of the crack and the mode I stress intensity factor were obtained. With the help of image processing software, accuracy and reliability was enhanced by twice multiplying and sharpening the measured isochromatics. Actual and reconstructed fringes were compared qualitatively. For quantitative comparison, percentage errors and standard deviations of the percentage errors were calculated for all measured input data by varying the number of terms in the stress function. The experimental results agreed with those predicted by finite element analysis and empirical equation within 2 percent error.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.1
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• pp.88-95
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• 2015

For the frequency-domain spectral fatigue analysis, the probability density function of stress range needs to be estimated based on the stress spectrum only, which is a frequency domain representation of the response. The probability distribution of the stress range of the narrow-band spectrum is known to follow the Rayleigh distribution, however the PDF of wide-band spectrum is difficult to define with clarity due to the complicated fluctuation pattern of spectrum. In this paper, efforts have been made to figure out the links between the probability density function of stress range to the structural response of wide-band Gaussian random process. An artificial neural network scheme, known as one of the most powerful system identification methods, was used to identify the multivariate functional relationship between the idealized wide-band spectrums and resulting probability density functions. To achieve this, the spectrums were idealized as a superposition of two triangles with arbitrary location, height and width, targeting to comprise wide-band spectrum, and the probability density functions were represented by the linear combination of equally spaced Gaussian basis functions. To train the network under supervision, varieties of different wide-band spectrums were assumed and the converged probability density function of the stress range was derived using the rainflow counting method and all these data sets were fed into the three layer perceptron model. This nonlinear least square problem was solved using Levenberg-Marquardt algorithm with regularization term included. It was proven that the network trained using the given data set could reproduce the probability density function of arbitrary wide-band spectrum of two triangles with great success.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.11
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• pp.1844-1851
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• 1997

Displacement fields and interface stresses are obtained by modifying the potential energy functional with a penalty function which enforces the continuity of stresses at the interface of two-materials. Based on the displacement field and the interface stresses, a new methodology to generate a continuous stress field over the entire domain including the interface of the dissimilar materials has been proposed by combining the L$^{2}$ projection method of stress-smoothing and the Loubignac's iterative method of improving the displacement field. Stress analysis was carried out on two examples which are made of highly dissimilar materials. As a result of the analysis, it is found that the proposed method provides improved continuity of the stress field over the entire domain as well as predicting accurate nodal stresses at the interface. In contrast, the conventional displacement-based finite element method provides significant stress discontinuties at the interfaces. In addition, it was found that the total strain energy evaluated from the improved continuous stress field converge to the exact value as increasing the number of iterations in the proposed method.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.2
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• pp.108-115
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• 2003

Suppression of cellular immunity is the host responses to surgical stress. When the body is exposed to surgical stress, decreased immunocyte function is one of the surgical stress-induced biologic responses. In all patients exposed to the surgical stress, peripheral blood lymphocyte numbers and function were suppressed until at least 2 weeks postoperatively. This immunosuppression was mainly due to a decrease of helper-inducer T cells, cytotoxic T cells, natural killer cells, and an increase of suppressor T cells. The blood levels of interleukin-6(IL-6) cytokine increase in response to surgical stress and cause an increase of so-called acute phase reactants, including C-reactive protein(CRP). In the previously damaged patients group, expected to early stress expose, immunosuppression was more developed than other normal groups. Cellular immunosuppression by surgical stress was mainly due to an increase of lymphocyte subsets that depress cellular immunity coupled with a decrease of the subsets that promote it. Overproduction of CRP in response to surgical stress may play an important role in the development of immunosuppression.

• Computers and Concrete
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• v.27 no.1
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• pp.73-83
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• 2021

In this article, the mechanical buckling analysis of simply-supported functionally graded plates is carried out using a higher shear deformation theory (HSDT) in conjunction with the stress function method. The proposed formulation is variationally consistent, does not use a shear correction factor and gives rise to a variation of transverse shear stress such that the transverse shear stresses vary parabolically through the thickness satisfying the surface conditions without stress of shear. The properties of the plate are supposed to vary across the thickness according to a simple power law variation in terms of volume fraction of the constituents of the material. Numerical results are obtained to study the influences of the power law index and the geometric ratio on the critical buckling load.

• Magazine of the Korea Concrete Institute
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• v.11 no.1
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• pp.279-288
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• 1999

The creep of concrete structures caused by variable stresses is generally calculated by step-by-step method based on the superposition of creep function. Although most practical application is carried out by this linear assumption. significant deviations between predictions and experiments have been observed when unloading takes place, that is. stress is reduced. This shows that the superposition of creep function does not describe accurately the effect of sustained compressive preload. The main purpose of this study is to propose a creep analysis model which is expressed with both creep function and creep recovery function where increase or decrease of stress is repeated. In these two function method, the creep behavior is modelled by using linear creep law for loading and creep recovery law for unloading. To apply two function method to time analysis of concrete structures, the calculation method of creep strain increment under varying stress is proposed. The calculation results based on the present method correlates very well with test data, but the conventional superposition method exhibits large deviation from test results. This paper provides a more accurate method for the time dependent analysis of concrete structures subjected to varying stress, i.e. increasing or decreasing stress. The present method may be efficiently employed in the revision of future concrete codes.