• Structural Engineering and Mechanics
• /
• 제53권4호
• /
• pp.703-723
• /
• 2015

In this paper optimization of volume fraction distribution in a thick hollow cylinder with finite length made of two-dimensional functionally graded material (2D-FGM) and subjected to steady state thermal and mechanical loadings is considered. The finite element method with graded material properties within each element (graded finite elements) is used to model the structure. Volume fractions of constituent materials on a finite number of design points are taken as design variables and the volume fractions at any arbitrary point in the cylinder are obtained via cubic spline interpolation functions. The objective function selected as having the normalized effective stress equal to one at all points that leads to a uniform stress distribution in the structure. Genetic Algorithm jointed with interior penalty-function method for implementing constraints is effectively employed to find the global solution of the optimization problem. Obtained results indicates that by using the uniform distribution of normalized effective stress as objective function, considerably more efficient usage of materials can be achieved compared with the power law volume fraction distribution. Also considering uniform distribution of safety factor as design criteria instead of minimizing peak effective stress affects remarkably the optimum volume fractions.

• 한국감성과학회:학술대회논문집
• /
• 한국감성과학회 2001년도 춘계학술대회 논문집
• /
• pp.225-230
• /
• 2001

Intensity of background noise is a factor significantly affecting both subjective evaluation of experienced stress level and associated electroencephalographic (EEG) responses during mental load in noisy environments. In the study on 27 subjects we analyzed the influence of the background white noise (WN) intensity on psychophysiological responses during a word recognition test. Electrocortical activity were recorded during baseline resting state and 40 s long performance on 3 similar Korean word recognition tests with different intensities of background WN (55, 70 and 85 dB).. An important finding in terms of physiological reactivity was similarity of all physiological response profiles between 55 and 70dB WN, i.e., none of physiological variables differentiated the two conditions, while 85dB WN resulted in a significantly different profile of reactions (higher fast beta power in EEG spectra). This condition was characterized by highest subjective rating of experienced stress, had more fast beta activity and had tendency of right hemisphere dominance, emphasizing the role of brain lateralization in negative affect control.

• 대한기계학회논문집
• /
• 제16권8호
• /
• pp.1493-1502
• /
• 1992

본 연구에서는 크랙선단의 소성변형에 의해 발생하는 소성유기 크랙개구거동 을 검토하기 위하여, 크랙선단 최인접 영역에서 COD를 측정할 수 있는 직접 측정법을 개발 사용하고 (1) 직접측정법의 적용범위와 크랙선단의 개구거동 (2) 측정위치에 따 른 개구하중의 변화 (3) 개구비에 영향을 주는 하중변수등에 대하여 고찰하였다.

• 성인간호학회지
• /
• 제22권1호
• /
• pp.11-18
• /
• 2010

Purpose: The purpose of the study was to identify levels of anxiety, stress hormone, lymphocytes, and neutrophils of the nursing students before an examination and to examine effects of social support on those variables related to taking examinations. Methods: Thirty eight healthy nursing students participated. They completed the questionnaire including state anxiety, test anxiety (VAS scale) and social support two weeks before the exam and again just before the exam. Simultaneously, a venous sample for ACTH, cortisol, lymphocytes & neutrophils count was drawn by a trained nurse. Descriptive statistics, paired t-test, student t-test, and Pearson's correlation with SPSS/WIN 14.0 were used to analyze the data. Results: Test anxiety scores and cortisol level on the exam day showed a significant increment compared with those on the non-exam day. The participants with higher levels of total social support scores showed significantly lower state anxiety on the exam day than those with lower levels of total social support scores. Conclusion: These data indicate a possible alteration in cortisol responsiveness to academic stress in nursing students. Social support would play an important role in modulation of academic stress.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권4호
• /
• pp.1733-1737
• /
• 2016

Background: Stress associated with fishing is known to trigger consumption of alcohol and tobacco among fishermen. This study aimed to assess the prevalence of tobacco and alcohol consumption among fishermen in Udupi Taluk in the state of Karnataka, India, and to study associations with health status and job stress. Materials and Methods: The study was conducted among 825 fishermen in Udupi Taluk of Karnataka between January-June 2015, using a two stage cluster sampling procedure. Associations between variables of interest were assessed using multivariable analysis and logistic regression models. Results: The prevalences of consumption of tobacco, alcohol and either of these substances were 64.2%, 45.6% and 86.9% respectively. There was a positive association between alcohol and any form of tobacco consumption with income but none with respondent's job stress and health status. Conclusions: Our study concluded that fishermen with poor health status are seen more among tobacco and alcohol users.

• 종양간호연구
• /
• 제11권2호
• /
• pp.93-100
• /
• 2011

The purpose of this study was to examine the effects of laughter therapy on mood, state anxiety, and serum cortisol based on a Stress-Coping Model for preoperative breast cancer patients. Methods: The study used a nonequivalent control group pretest-posttest design. The participants were 40 breast cancer patients who were admitted to one general hospital for surgery in 2009 (experimental group 23, control group 17). The experimental group received one hour laughter therapy consisting of dance, lots of laughter techniques, and meditation. Results: The mean ages were 47 years (experimental group) and 49 years (control group). There were no significant differences in demographic and disease-related characteristics between the two groups. After the intervention, the scores of mood and state-anxiety of experimental group were significantly improved than those of control group. However, no difference was found in serum cortisol. Conclusion: The laughter therapy was partially effective in improving stress response in patients with breast cancer. Further research is needed to develop and evaluate the longer periods of interventions to testify the effects on serum cortisol, and other biochemical variables.

• Journal of Preventive Medicine and Public Health
• /
• 제22권1호
• /
• pp.90-101
• /
• 1989

Recently concerns on work stress and mental health status of industrial workers were increased. The purpose of this study was to investigate the work stress measured by PSI (psychiatric symptom index) according to socio-demographic variables. The study population was consisted with two types of group; manual and clerical workers. The major findings of this study were as follows; Mean scores of psychiatric symptom in manual workers were higher in female, youth, educated, unmarried and divorced, noisy condition, that in clerical workers was higher in aged. Mean scores of psychiatric symptom were highly affected by degree of work autonomy, self-esteem, and self-efficacy in both groups. The higher the work autonomy, self-esteem, and self-efficacy, the lower the mean scores of work stress it showed. Psychiatric symptom index was explained with the work autonomy, self-esteem, self-efficacy through multiple stepwise regression. The annual admission rates were high in highly ranked groups on each psychiatric symptom dimension.

• 간호행정학회지
• /
• 제22권4호
• /
• pp.373-383
• /
• 2016

Purpose: This study was conducted to develop a resilience training program for nurses and test its effects. Methods: A non-equivalent experimental group and a control group pretest-posttest study design was used with 56 participating nurses (28 nurses in the experimental group and 28 nurses in the control group). The resilience training program was provided to participants for 4 weeks from August 12 to September 4, 2013. Each session was scheduled for two hours per week. Participants completed the tools for resilience, positive affect, and perceived stress assessment. Data were analyzed using ${\chi}^2$ test, Independent t-test, and 2*2 repeated measures multivariate analyses of variance (MANOVAs) with the SPSS/WIN 21.0 program. Results: Application of the resilience training program significantly helped nurses enhance their resilience and positive affect to workplace adversity, and reduce their perceived stress. There were significant positive differences for these variables in the experimental group compared to the control group. Conclusion: The findings indicate that the resilience training program for nurses is effective and can be used as an intervention for a stress management guide for nurses.

• 한국전산구조공학회논문집
• /
• 제22권4호
• /
• pp.331-334
• /
• 2009

본 논문에서는 원자적 계산(atomistic calculation)을 위한 해석적 모델로 surface relaxation model을 제시한다. 기존의 분자정역학(molecular statics)이 모든 원자의 위치를 자유도로 선정하여 사용하는데 반하여, 이 모델은 면내방향에 해당하는 두 개의 자유도로 나노박막의 원자 위치를 기술하는 매우 간단한 방법이다. 본 연구에서는 surface relaxation model을 이용하여 표면응력(surface stress)과 표면강성계수(surface stiffness tensor)와 같은 표면인자(surface parameter)의 계산을 수행하고, surface stress model을 이용하여 평형상태에서의 원자의 위치정보를 계산한다. 그리고 surface relaxation model을 검증하기 위하여 분자동역학 전산모사(molecular dynamics simulation)의 수치 결과가 제시되며, 본 연구에서 계산한 equilibrium strain과 비교 검증한다.

• 근관절건강학회지
• /
• 제17권2호
• /
• pp.212-221
• /
• 2010

Purpose: The purpose of this study was to determine the effects of music therapy (Jang-Gu) on depression, stress, pain and body discomfort in women with osteoarthritis. Methods: The study is designed using one group pretest-posttest experimental design. 31 arthritis patients, the subjects of the group participated in the music therapy program. The program was provided for 12 weeks (two times per week). The questionnaires were used to measure the outcome variables before and after the program. Data were analyzed with the SPSS 17.0 using descriptive statistics, paired t-test. Results: Depression, Stress, Pain did not decrease. But body discomfort decreased (p=0.001). Conclusion: Therefore this program was effective in body discomfort and can be a community based self-help management program for arthritis patient.