• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.2
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• pp.145-152
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• 2009

SGBEM(Symmetric Galerkin Boundary Element Method)-FEM alternating method has been proposed by Nikishkov, Park and Atluri. In the proposed method, arbitrarily shaped three-dimensional crack problems can be solved by alternating between the crack solution in an infinite body and the finite element solution without a crack. In the previous study, the SGBEM-FEM alternating method was extended further in order to solve elastic-plastic crack problems and to obtain elastic-plastic stress fields. For the elastic-plastic analysis the algorithm developed by Nikishkov et al. is used after modification. In the algorithm, the initial stress method is used to obtain elastic-plastic stress and strain fields. In this paper, elastic-plastic J integrals for three-dimensional cracks are obtained using the method. For that purpose, accurate values of displacement gradients and stresses are necessary on an integration path. In order to improve the accuracy of stress near crack surfaces, coordinate transformation and partitioning of integration domain are used. The coordinate transformation produces a transformation Jacobian, which cancels the singularity of the integrand. Using the developed program, simple three-dimensional crack problems are solved and elastic and elastic-plastic J integrals are obtained. The obtained J integrals are compared with the values obtained using a handbook solution. It is noted that J integrals obtained from the alternating method are close to the values from the handbook.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.521-527
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• 2013

This study provides the elastic stress intensity factors, K, for circumferential and longitudinal surface cracked straight pipes under single or combined loads of internal pressure, bending, and torsion based on three-dimensional (3D) finite element (FE) analyses. FE results are compared with two different types of defect assessment codes (API-579-1 and RCC-MR A16) to prove the accuracy of the FE results and the differences between the codes. Through the 3D FE analysis, it is found that the stress intensity factors are sensitive to the number of elements, which they were believed to not be sensitive to because of path independence. Differences were also found between the FE analysis results for crack defining methods and the results obtained by two different types of defect assessment codes.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.2
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• pp.66-81
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• 1989

The characteristics of resilient modulus(Mr) which dominates the life of pavement and the design of pavement were investigated on the test specimens which were cement treated and non-treated of the three different soil types. The results are summarized as follows : 1. The resilient modulus was decreased by increasing the cyclic deviator stress ($\sigma$d) , especially the resilient modulus was gradually decreased or sometimes increased when the value of ad was greater than 0.75- 1. 0kg/cm$^2$. 2. The resilient modulus was increased by increasing the homogeneous confined stress ($\sigma$do) and such phenomena were distinct on the coarse soils. 3. The resilient modulus was increased by increasing the ratio of confined stress(Kc), and this phenomena were eminent on the coarse soils too, and the higher permanent strain was showed by increasing the value of Kc. 4. In the drained cyclic triaxial compression test, the value of ad, Kc, and (Oho) was introduced by the following interrelated equations which were similar to the Mr model of Cole. Kcn/Mr=K1(J$_2$/ $\tau$oct)K2 ............. (coarse soli) Mcn/Mr=K3($\sigma$dp/ $\tau$f)k4 ...............(fine soils) 5. The stress path was not much affected by the value of Mr, however, moisture content, dry desity, and contant of fines affected the value of Mr. 6. In the soil-cement specimens, the resilient compression strain($\varepsilon$d) was decreased by the increment of the $\sigma$ho, and Mr was decreased by increasing the $\sigma$d 7. In the flexible pavement. the cement treated layer should be designed not to fail by the fatigue before the designed traffic load, and actually the pavement could cover the traffic load to a certain extent under the post-crack phase, therefore farther studies on this phenomena' are required in the design analysis. 8. The finite element computer program (ANALYS) was used for displacement analysis of pavement containing the cement-treated layer, The result showed that the program used for this analysis was proved to be usable.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.192-195
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• 2004

Products of gridded surface wind and windstress vectors over the world ocean have been constructed by satellite scatterometer data with highly temporal and spatial resolutions. Even if the ADEOS-II/SeaWinds has supplied surface wind data only for short duration in Apr. to Oct. 2003 to us, it permits us to construct a product with higher resolution together with the Qscat/SeaWinds. In addition to our basic product with its resolution of $1^{\circ}\times1^{\circ}$ in space and daily in time, we try to construct products with $1/2^{\circ}\times1/2^{\circ}$ and semi- and quarter-daily resolution. These products are validated by inter-comparison with in-situ data (TAO and NDBC buoys), and also compared with numerical weather prediction(NWP) ones (NCEP reanalysis). Result reveals that our product has higher reliability in the study area than the NCEP's. For the open ocean regions in the middle and high latitudes where there are no in-situ data, we find that there are clear differences between them. Especially in the southern westerly region of 400-600S, the' wind-stress magnitudes by the NCEP are significantly larger than the others, suggesting that they are overestimated. We also calculate wind-stress curl field that is an important factor for ocean dynamics and focus its spatial character in the northwestern Pacific around Japan. Positive curl areas are found to cover from southwest to northeast in our focus region and almost correspond to the Kuroshio path. It is suggested that the vorticity field in the lower atmosphere is related to the upper oceanic one, and thus an aspect of air-sea interaction process.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.329-336
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• 2019

This study is a descriptive research study that examines the level of terminal care nursing care and the effects on terminal nursing in the internal and external control beliefs of nurses in the nursing geriaic hospital.. The subjects consisted of 442 nurses, and data were collected through structured questionnaires.. The data were analyzed with descriptive that used SPSS WIN 22.0, and AMOS 5.0 statistical program was hypothetical model and path analysis of research hypothesis. As a result, terminal care of geriatric hospital nurses was statininificant to the terminal care stress, fatigue and locus of internal & external control. and the higher the internal control belief, the less stress of the terminal care and the higher the terminal care performance As a result, this study providers a more terminal care performance, It is considered that nursing hospital nurses who develop strategic programs and terminal care nursing will need to provide quality nursing education and work environment improvement.

• Journal of the Korea Convergence Society
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• v.8 no.6
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• pp.65-73
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• 2017

The purpose of this study is a path modeling study to examine the factors that affect nursing students' quality of life. Subject consists of 209 nursing students in B City and G City. Collected data was analyzed using SPSS 22.0 and Amos 22.0. Variables that directly affect nursing students' quality of life were physical condition and stress, and the variable that directly affect stress were monthly income and physical condition. In other words, they were more stressed as the monthly income was lower(${\beta}=-,067$ p=.030) and their physical condition was worse(${\beta}=-.109$, p=.003), and their quality of life increased as they had sufficient physical condition(${\beta}=.083$, p=.013) and less stress(${\beta}=.-213$, p=.001). Based on the results of this study, educational programs to enhance the quality of life in order to improve information support and affectionate support of nursing students should be developed and applied.

• Journal of the Korean Home Economics Association
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• v.45 no.5
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• pp.121-133
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• 2007

The purpose of this study was to investigate the psychological wellbeing as applied to the bioecological family life welfare model, concerning individual attributes, family backgrounds, and family processes across the family life cycles. Based on Bronfenbrenner's bioecological perspective, the "bioecological family welfare model", which includes person (individual attributes), context (family background), process (mechanism - family process), and time (the family life cycles), was applied as a research paradigm for this study. The sample for the questionnaire study comprised for 900 families, considering the family life cycle in Busan and the Kyungnam area. The families were categorized into 6 family life cycles based on Duvall and Hill's family life cycle. For the final analysis, 628 families were used. According to the path analysis results, the length of commitment before marriage and self-esteem had significant effects on the stress coping ability. Several individual attributes and family backgrounds such as age, length of marriage, family life cycle, self-esteem and stress coping ability had significant effects on marital adjustment. The family life cycle and age were significant variables on family function. The significant variables on psychological wellbeing were monthly income, length of commitment before marriage, stress coping ability and marital adjustment. The regression model showed that the variables of the individual attributes, context and family process accounted for 51% of the psychological wellbeing. The results show that the suggested research model was significant and effective to explain the mechanism of psychological wellbeing. Individual attributes and family context have an impact on stress coping, marital adjustment, and family function, which in turn affect psychological wellbeing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.622-628
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• 2016

The aim of this study was to clarify how the role stress of administrative workers in medical institutions affects burnout, job satisfaction, and organizational commitment. The study conducted surveys on administrative workers at ten general hospitals with more than 200 beds for one month between July 13 and August 18, 2015. The surveys then underwent factor analysis, average variation extraction, a suitability index of the research model, and a path-coefficient estimation analysis of the research model using AMOS 18.0. The main results revealed a positive (+) effect according to the role conflict and role excess on burnout, and a negative (-) effect of burnout on job satisfaction, while they displayed no significant relationship with organizational commitment. These results suggest that clear guidelines and unity in instructions are needed to reduce the role of stress in cooperative tasks between departments and that optimizing the roles of organization members by accurately measuring and weighing tasks can increase the attachment to the organization and ultimately improve the individual job performance.

• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.259-271
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• 2019

It is important to obtain reasonable predictions of the extent of the damage during maritime accidents such as ship collisions and groundings. Many fracture models based on different mechanical backgrounds have been proposed and can be used to estimate the extent of damage involving ductile fracture. The goal of this study was to compare the damage extents provided by some selected fracture models. Instead of performing a new series of material constant calibration tests, the fracture test results for the ship building steel EH36 obtained by Park et al. (2019) were used which included specimens with different geometries such as central hole, pure shear, and notched tensile specimens. The test results were compared with seven ductile fracture surfaces: Johnson-Cook, Cockcroft-Latham-Oh, Bai-Wierzbicki, Modified Mohr-Coulomb, Lou-Huh, Maximum shear stress, and Hosford-Coulomb. The linear damage accumulation law was applied to consider the effect of the loading path on each fracture surface. The Swift-Voce combined constitutive model was used to accurately define the flow stress in a large strain region. The reliability of these simulations was verified by the good agreement between the axial tension force elongation relations captured from the tests and simulations without fracture assignment. The material constants corresponding to each fracture surface were calibrated using an optimization technique with the minimized object function of the residual sum of errors between the simulated and predicted stress triaxiality and load angle parameter values to fracture initiation. The reliabilities of the calibrated material constants of B-W, MMC, L-H, and HC were the best, whereas there was a high residual sum of errors in the case of the MMS, C-L-O, and J-C models. The most accurate fracture predictions for the fracture specimens were made by the B-W, MMC, L-H, and HC models.

• Journal of Oriental Neuropsychiatry
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• v.26 no.1
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• pp.63-78
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• 2015

Objectives: Pinelliae Rhizoma has traditionally been used as an anti-depressant in oriental medicine. This study is to investigate the effect of Pinelliae Rhizoma extract (PRe) on psychological stress in genome wild expression of mice. Methods: After giving physical stress to mice, PRe was orally administered with 100 mg/kg/day for five days. After extracting whole brain tissue from the mice, their genome changes were observed by micorarray analysis method. The genome changes were analyzed by IMAGENE 4.0, TREEVIEW, FatiGo algorithems, BOND database, cytoscape program, etc. Results: 1. PRe administered group were remained at normal level; 60% of increase was shown in expressed genes by physical stress, and 65% of decrease was shown in expressed genes by psychological stress. 2. Genes with increased expression in control group that remained at a normal state in PRe administered group were involved with the gene of a cellular metabolic process on biological process, protein binding on molecular function, and cell part on cell composition. The pathway was found to be cytokin-cytokin receptor interaction. 3. Genes with decreased expression in control group that remained at a normal state in PRe administered group were involved with the gene of a cellular metabolic process on biologiacl detail and coupled ATPaes activity on molecular function. This gene related path was Ubiquintin mediated proteolysis etc. 4. Core node genes analyzed by protein interaction network were Vinculin, Cell sdivision cycle 42 homolog (S. cerevisiae) etc. They played an important role in maintaining cytoskeleton and controlling cell cycle. Conclusions: Several genes were up-regulated and down-regulated in response to psychological stress. The expression of most of the genes that were altered in response to psychological stress was restored to normal levels in PRe treated mice. When the interaction network information was analyzed, the recovery of the core node genes in PRe treated mice indicates that this final set of genes may be the effective target of PRe.