• Journal of the Korean Data and Information Science Society
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• v.16 no.4
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• pp.791-799
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• 2005

We consider two components parallel system in which the lifetimes have the bivariate Pareto model with bivariate random censored data. We assume that bivariate Pareto model is affected by common stress which is independent of the lifetimes of the components. We obtain estimators for the system reliability based on likelihood function and relative frequency. Also we construct approximated confidence intervals for the reliability based on maximum likelihood estimator and relative frequency estimator, respectively. Finally we present a numerical study.

• Journal of the Korean Data and Information Science Society
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• v.15 no.3
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• pp.655-662
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• 2004

In this paper, we assume that strengths of two components system follow a type II bivariate Pareto model with bivariate type I censored data. And these two components are subjected to a common stress which is independent of the strengths of the components. We obtain estimators for the system reliability based on likelihood function and relative frequency, respectively. Also we construct approximated confidence intervals for the reliability based on maximum likelihood estimator and relative frequency estimator, respectively. Finally we present a numerical study.

• Journal of the Korean Data and Information Science Society
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• v.5 no.2
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• pp.11-18
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• 1994

Sample sizes for experiments concerned with inference on R=Pr(X

• Korean Security Journal
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• no.12
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• pp.177-200
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• 2006

This research result that analysis as following. First, difference that keep in mind partially as result that verify difference of job-stress by demography special qualitys that is common people guard's society and turnover intention appeared. Second, result that analyze relation with job-stress and turnover intention, displayed statical correlation in job environment. Third, result that keep in mind as statistical as result that verify effect that common people guard's job-stress gets to turnover intention appeared. During is job-stress variable, was expose that exert effect that keep in mind to turnover intention job surrounding and job special quality. Suggestion point through this research as following be. To raise common people guard's job-stress and turnover intention. system improvement strategy about social estimation etc.. is effective, and do on the basis of this and may have to establish common people guard's enhancing morale plan strategy, low complement that can exert negative impact in change of post for example, line of duty that it is seldom competence, daytime that can elicit common people guards' job satisfaction. Is in visual point that activation of continuous research is leaned against by depth interview and review through qualitative research was insufficient relatively in virtue research so far in research after.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.1
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• pp.41-51
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• 2004

FRP re-bar in concrete structures could be used as a substitute of steel re-bars for that cases in which aggressive environment produce high steel corrosion, or lightweight is an important design factor, or transportation cost increase significantly with the weight of the materials. But FRP fibers have only linearly elastic stress-strain behavior; whereas, steel re-bar has linear elastic behavior up to the yield point followed by large plastic deformation and strain hardening. Thus, the current FRP re-bars are not suitable concrete reinforcement where a large amount of plastic deformation prior to collapse is required. The main objectives of this study in to evaluate the tensile behavior and the fracture mode of hybrid FRP re-bar. Fracture mode of hybrid FRP re-bar is unique. The only feature common to the failure of the hybrid FRP re-bars and the composite is the random fiber fracture and multilevel fracture of sleeve fibers, and the resin laceration behavior in both the sleeve and the core areas. Also, the result of the tensile and interlaminar shear stress test results of hybrid FRP re-bar can provide its excellent tensile strength-strain and interlaminar stress-strain behavior.

• Safety and Health at Work
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• v.14 no.3
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• pp.325-331
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• 2023

Background: Heat stress is a harmful physical hazard in many occupational settings. However, consequences of occupational heat exposure among workers in a sugarcane factory in Ethiopia are not well characterized. This study aimed to assess the level of occupational heat exposure-related symptoms and contributing factors. Methods: In this cross-sectional study, five workstations were selected for temperature measurement. Heat stress levels were measured using a wet-bulb globe temperature index meter. A stratified random sampling technique was used to select 1,524 participants. Heat-related symptoms were assessed using validated questionnaires. Results: The level of occupational heat exposure was 72.4% (95% CI: 70.2%-74.8%), while 71.6% (95% CI: 69.3%-74.9%) of participants experienced at least one symptom related to heat stress. The most common heat-related symptoms were swelling of hands and feet (78%), severe thirst (77.8%) and dry mouth (77.4%). The identified risk factors were a lack of reflective shields (AOR: 2.20, 95% CI: 1.53, 3.17), not-enclosed extreme heat sources (AOR: 1.76, 95% CI: 1.23, 2.51), a lack of access to shade (AOR: 9.62, 95% CI: 6.20, 14.92), and inappropriate protective clothing provision (AOR: 1.58, 95% CI: 1.27, 2.71). Conclusions: The burden of occupational heat exposure and heat-induced symptoms was high. Lack of reflective shields, the absence of enclosed extreme heat sources, a lack of access to shade, and inappropriate protective clothing provision were considerable attributes of heat stress. Therefore, the use of mechanical solutions to stop heat emissions at their sources and the key factors identified were areas for future intervention.

• Safety and Health at Work
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• v.13 no.4
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• pp.469-474
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• 2022

Background: Nowadays, counter-productive work behaviors (CWBs) have turned into a common and costly position for many organizations and especially health centers. Therefore, the study was carried out to examine and compare the demand-control-support (DCS) and effort-reward imbalance (ERI) models as predictors of CWBs. Methods: The study was cross-sectional. The population was all nurses working in public hospitals in Hamadan, Iran of whom 320 were selected as the sample based on simple random sampling method. The instruments used were Job Content Questionnaire, Effort-Reward Imbalance Questionnaire, and Counterproductivity Work Behavior Questionnaire. Data were analyzed using correlation and regression analysis in SPSS18. Results: The findings indicated that both ERI and DCS models could predict CWB (p ≤ 0.05); however, the DCS model variables can explain the variance of CWB-I and CWB-O approximately 8% more than the ERI model variables and have more power in predicting these behaviors in the nursing community. Conclusion: According to the results, job stress is a key factor in the incidence of CWBs among nurses. Considering the importance and impact of each component of ERI and DCS models in the occurrence of CWBs, corrective actions can be taken to reduce their incidence in nurses.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.137-143
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• 2008

For most bearings, it is a common requirement to have long durability. Especially wheel bearing fatigue life is the most important in automotive quality. The contact fatigue life analysis of automotive wheel bearing considering real raceway rough surface is presented in this paper. Contact stresses are obtained by contact analysis of a semi-infinite solid based on the use of influence functions; the subsurface stress field is obtained using rectangular patch solutions. Mesoscopic multiaxial fatigue criterion which can yield satisfactory results for non-proportional loading is then applied to predict fatigue damage. Suitable counting method and damage rule were used to calculate the fatigue life of random loading caused by rough surface. The life analysis considering real rough surface of wheel bearing raceway is in good agreement with the experimental results.

• The Korean Journal of Applied Statistics
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• v.9 no.2
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• pp.119-134
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• 1996

Accelerated life testing (ALT) of a system is commonly used to reduce time and cost. ALT is achieved by subjecting the test systems to more severe conditions than the normal ones to obtain estimates of life distribution under normal condition. The major interest of this research is to use a model of incorporating the common environmental effect on the components serially linked into a system-so called frailty model for the system life time distribution under each stress and to discuss the related data analysis and comparison of the model with the generally used one. The profile likelihood is used to get an initial values required to compute maximum likelihood estimates and simulation is carried for comparison.

• Journal of Agricultural Extension & Community Development
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• v.11 no.1
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• pp.95-110
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• 2004

The purposes of this study were to analyze rural youth's leisure activity and to suggest measures for activation. This study was conducted by review of literature and questionnaire, The data was collected from 1,209 stratified cluster random sampled rural youth who are in middle school and high school. To analyze the data, SPSS/WIN program was employed. The major finding of the study were as follows: 1) About 30% of rural youths had less than 1-2 hours for leisure activity in daily life and more than 8 hours for leisure activity during the weekend, and over 40% of rural youths had no plan for leisure activity. 1) They recognized that leisure activity made them enjoy common life, decrease their stress, and get new experience far self-development, 3) participation in sports, organized-activity and self-directed activity of the middle schools youths were higher compare to youths in high schools, 4) to activate leisure life, rural youths expected to get a) direct support for participating leisure activity expenses(27%), b) develop and diffusion of diverse and interesting leisure programs(23%), and c) securing appropriate leisure facilities(22%).