• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.3
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• pp.233-244
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• 2001

Stress-strain behaviour of soil varies based on stress path and stress history. There has been few study on the characteristics of yielding curve which has anisotropic compression stress history in decomposed granite soil. During this study, various stress path tests in previous anisotropic compression stress history are performed on compacted decomposed granite soil sampled at Iksan, Chonbuk. Yielding points are determined from various stress-strain curves (${\eta}-{\varepsilon}$, ${\eta}$-v, and ${\eta}$-k, ${\eta}$-W curves). Stress-strain curve is certified which shows yielding point very clearly. The shape and characteristics of anisotropic compression yielding curves are examined. The main results are summarized as follows : 1) p' constant and compressive direction in stress paths, which has experienced previous anisotropic compression stress history, shows relatively dear yielding points. 2) Yielding curves defined from ${\eta}$-k and ${\eta}$-W curve show almost perfect ellipse. 3) Directions of plastic strain incremental vector($dv^p/d{\varepsilon}^p$) are not perpendicular to yielding curve.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.2
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• pp.86-95
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• 2003

During this study, constant stress ratio tests with previous compression anisotropic stress history are performed on compacted decomposed granite soil sampled at Iksan, Jeonbuk. Yielding points are determined from stress-strain curves. The shape and characteristics of compression anisotropic yield curves is examined. In addition, the measured value of yielding curve and stress-strain behavior is predicted by Yasufuku's anisotropic constitutive model based on non-associated flow rule. The main results are summarized as follows : 1) Shape of yielding curves shows almost ellipse but asymmetry with respect to stress path during previous consolidation stress. 2) Yasufuku's anisotropic constitutive model is suitable in evaluation of yielding curves on anisotropic consolidated decomposed granite soil. 3) The predicted stress-strain curve shows reasonable agreement to measured behaviours.

• Steel and Composite Structures
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• v.29 no.1
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• pp.125-138
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• 2018

The research on the confinement behavior of ultra high performance concrete without and with the use of steel fibers (UHPC and UHPFRC) has been extremely limited. In previous studies, authors experimentally investigated the axially compressive behavior of circular steel tube confined concrete (STCC) short and intermediate columns with the employment of UHPC and UHPFRC. Under loading on only the concrete core, the confinement effect induced by the steel tube was shown to significantly enhance the utimate stress and its corresponding strain of the concrete core. Therefore, this paper develops a simplified stress - strain model for circular STCC columns using UHPC and UHPFRC with compressive strength ranging between 150 MPa and 200 MPa. Based on the regression analysis of previous test results, formulae for predicting peak confined stress and its corresponding strain are proposed. These proposed formulae are subsequently compared against some previous empirical formulae available in the literature to assess their accuracy. Finally, the simplified stress - strain model is verified by comparison with the test results.

• Korean Journal of Culture and Social Issue
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• v.18 no.2
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• pp.215-234
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• 2012

The purpose of this study was to explore linkages between stress and a range of individual difference factors on children's memory for a potentially stressful event. Children (N=63) aged from 4 to 10 years, who undergone a minor dental operative procedure were evaluated. Overall, the results of this study replicated and extended previous findings of the related literature, providing some further evidence for a negative relation between stress and children's recall. More considerable variation in individual difference variables, in particular, children 's stress coping strategies, quality of previous experiences, amount of the advanced parental preparation were existed among the children, influencing the relation between the level of stress and children's remembering of a stressful event. Future inquiries for understanding theoretical, clinical, and forensic issues in children's remembering of a stressful event were discussed.

• Journal of Korean Academy of Nursing
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• v.5 no.2
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• pp.29-37
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• 1975

The purpose of this study was to measure the extent of stress existing in hospitalized patients which might play an important part in delaying recovery of patients. The study was conducted July l0th through 16th, 1975; a total of 146 patients from 2 general hospitals in Seoul were sampled. Questionnaire, formulated by the researcher, were used to gather necessary information concerning stress in accordance with the physical, psychological, economical and social variables. Data were analysed by mean stress score, and the significances were tested by Critical Ratio. The results were as follows ; 1. No significant difference was revealed in accordance with sex, however, male patients showed higher stress scores on the economic variables. 2. No. significant difference was apparent in accordance with marital status, however, the unmarried showed a tendency of higher stress scores at all variables. 3. Significant difference was revealed between the age group of 35-49 years and that of over 50 years; the age group of 18-34, and 35-49 years showed higher stress scores. 4. No. significant difference was revealed in accordance with previous experience of hospitalization, however, the group with previous experience tends to show higher stress scores in all variables. 5. No significant difference was revealed in accordance with the types of admission, however, group admitted on emergency showed higher stress scores compared to the group admitted plained in advance at social and economic variables. 6. No significant difference was revealed in accordance with the length of hospitalization, however, tendencies were apparent that the longer the length of hospitalization, the lower the mean stress scores.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.1
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• pp.30-40
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• 2016

The paper investigates the previous studies about welding residual stresses in nuclear components. First, various residual stress measurement methods are reviewed in applicability. Second a finite element welding residual stress analysis technique, which was developed from the viewpoint of FFS (Fitness-For-Service) assessment, is explained. Third, characteristics of the welding residual stresses on J-groove welds and butt welds were presented via investigating the previous studies. Last, engineering formulae for residual stresses in the FFS assessment codes such as R6 and API 579/ASME FFS-1 Code is summarized.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.25-35
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• 2015

The goal of this study was to review the visual grading and allowable stress determination methodologies for the domestic softwood. Previous studies used different grading (KFRI 1995-27, KFRI 2000-39, KFRI 2007-3, KFRI 2009-1) and allowable stress determination methodologies (ASTM D 245, KS F 2152, JAS 1990). The results of the visual grading were different by each researcher. Compared to the $1^{st}$ grade proportion from the previous studies using the previous specification on visual grading (KFRI 1995-2007), a higher $1^{st}$ grade proportion was found from the studies using the current specification (KFRI 2009). Compared to the allowable stress values from the small clear sample, the higher allowable stress values from the structural size were found. The results indicated that the strength reduction factor used in small clear sample was too conservative for the different grades. To obtain consistent results for the grade, it is required to have experts in visual grading and authorized organizations. An official standard methodology for the allowable stress value determination needs to be defined for the reliable stress value.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.1-10
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• 1998

Testing high reliability devices under nomal operating condition is difficult, because the devices are not likely to fail in the relatively short time available for tests. For most applications it is necessary to accelerate the causes of failure by increasing a stress above its nomal value. Previous accelerated life test(ALT) plans have shown how to find optimum allocation, lowest stress and sample size subject to minimizing the variance of mean life estimator. In these ALT plans, the highest acceptable test-stress was assumed to be specified in advance by the experimenter but there is no guidance for selecting it. This assumption is, however, inappropriate for many applications. Testing devices at too-high stress levels can invalidate the extrapolation model, or introduce failure mechanisms that are not anticipated under nomal operating conditions. In this paper, we propose new 4:2:1 compromise plans using Min-Max method to minimize this risk and present minimized test-stress levels(max, middle, min), and find sample allocation based on Min-Max 4:2:1 compromise plans. In result, we compare previous 4:2:1 compromise plans specified maximum test-stress with Min-Max 4:2:1 compromise plans minimized maximum test-stress.

• International Journal of Concrete Structures and Materials
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• v.18 no.2E
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• pp.111-116
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• 2006

The purpose of this study is to investigate the relations between unbonded tendon stress and its influential parameters, i.e. bonded reinforcement ratio, span/depth ratio, and loading type. To this end, the influence of such parameters was examined with twenty eight test results of previous studies. Afterwards, an experimental study was carried out with twenty one test specimens. The investigation of previous and current experiments revealed the followings; (1) The bonded reinforcement ratio and prestressing ratio were proved to be important variables on the unbonded tendon stress. (2) The ratio of span to depth and the type of loading affected the unbonded tendon stress partially although their effects varied with bonded reinforcement ratio. (3) AASHTO LRFD Code and Moon/Lim's design equations predicted the experimental results well with the safety margin.

• Anxiety and mood
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• v.2 no.2
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• pp.86-93
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• 2006

Depression, anxiety and stress are important components of theories of pathological gambling and are often foci of treatment with patients with gambling problems. In the present review we attempt to examine the relationship between anxiety, depression, stress and pathological gambling. Although the previous studies on this subject are limited and the relationship is unclear and complex, our review on the previous studies and clinical experiences on this subject could offer new insights for the assessment and treatment of pathological gamblers.