Human reliability analysis in de-energization of power line using HEART in the context of Z-numbers.

Investigation reveals that a high percentage of incident causes are ascribed to some forms of human error. To effectively prevent incidents from happening, Human Reliability Analysis (HRA), as a structured way to represent unintentional operator contribution to system reliability, is a critical issue. Human Error Reduction and Assessment Technique (HEART) as a famous HRA technique, provides a straightforward method to estimate probabilities of human error based on the analysis of tasks. However, it faces varying levels of uncertainty in assigning of weights to each error producing condition (EPC), denoted as assessed proportion of affect (APOA), by experts. To overcome this limitation and consider the confidence level (reliability or credibility) of the experts, the current study aimed at proposing a composite HEART methodology for human error probability (HEP) assessment, which integrates HEART and Z-numbers short for, Z-HEART. The applicability and effectiveness of the Z-HEART has been illustrated in the de-energization power line as a case study. Furthermore, a sensitivity analysis is fulfilled to investigate the validity of the proposed methodology. It can be concluded that Z-HEART is feasible for assessing human error, and despite the methodological contributions, it offers many advantages for electricity distribution companies.

Risk assessment in academic laboratories in the west of Iran: compare the CHRA and the RSLs methods.

In the laboratories staffs, there is potential for adverse health effects in exposure to chemicals. Therefore, risk assessment is one of the main issues to prevent these effects. The purpose of this study was to assess the health risk of laboratory staffs and compare the two methods, including 'Chemical Health Risk Assessment' (CHRA) and 'Regional Screening Levels' (RSLs), that developed by the Department of Occupational Safety and Health of Malaysia and the Environmental Protection Agency respectively. Using these two methods, the places with the highest risk were identified. Comparisons showed that RSLs is a precise method without personal judgment. The CHRA is a simple method for wider chemicals that categorize risk. But CHRA includes fewer parameters compared to RSLs, as well as personal judgment. The results of the present study showed that two methods did not compatible. According to the characteristics of these two methods, it is recommended to use them as a compliment each other to obtain accurate results.