Advanced system engineering approaches to dynamic modelling of human factors and system safety in sociotechnical systems

Sociotechnical systems (STSs) indicate complex operational processes composed of interactive and dependent social elements, organizational and human activities. This research work seeks to fill some important knowledge gaps in system safety performance and human factors analysis using in STSs. First, an in-depth critical analysis is conducted to explore state-of-the-art findings, needs, gaps, key challenges, and research opportunities in human reliability and factors analysis (HR&FA). Accordingly, a risk model is developed to capture the dynamic nature of different systems failures and integrated them into system safety barriers under uncertainty as per Safety-I paradigm. This is followed by proposing a novel dynamic human-factor risk model tailored for assessing system safety in STSs based on Safety-II concepts. This work is extended to further explore system safety using Performance Shaping Factors (PSFs) by proposing a systematic approach to identify PSFs and quantify their importance level and influence on the performance of sociotechnical systems’ functions. Finally, a systematic review is conducted to provide a holistic profile of HR&FA in complex STSs with a deep focus on revealing the contribution of artificial intelligence and expert systems over HR&FA in complex systems. The findings reveal that proposed models can effectively address critical challenges associated with system safety and human factors quantification. It also trues about uncertainty characterization using the proposed models. Furthermore, the proposed advanced probabilistic model can better model evolving dependencies among system safety performance factors. It revealed the critical safety investment factors among different sociotechnical elements and contributing factors. This helps to effectively allocate safety countermeasures to improve resilience and system safety performance. This research work would help better understand, analyze, and improve the system safety and human factors performance in complex sociotechnical systems

Comparing the Analgesic Effect of Aminophylline and Hyoscine with Morphine on Renal Colic: a Randomized Clinical Trial

Introduction: Although narcotics are effective for pain relief in these patients, they have little impact on the underlying cause. Therefore, surveys have been conducted to find more effective agents. Objective: This study conducted to compare the analgesic effect of aminophylline and hyoscine combination with morphine on renal colic patients. Methods: This double-blind clinical trial was conducted on patients with renal colic caused by urinary tract stones. Subjects were selected via convenience sampling method. Patients were randomly divided into two groups based on whether they received aminophylline + hyoscine or morphine. Before drug administration, one researcher was asked to measure the pain of the patients using Graduated Numbered Visual Analogue Scale (GN-VAS). Afterward, 20 mg of hyoscine along with 3 mg/kg of aminophylline in 100 cc normal saline was injected during 10 minutes into patients in the one group, whereas 0.1 mg/kg of morphine was intravenously with 100 cc normal saline to align two groups, administered to the subjects in another group. Half an hour after the administration of drugs, pain was measured for the second time. Vital signs and side effects were all recorded. Results: In this study, 95 patients (47 patients in the aminophylline+hyoscine group and 48 patients in the morphine group) remained in the trial until the end. The difference in sex distribution(p=0.227) and age(p=0.680) of the two groups was not statistically significant. Median of pain intensity was not significantly different between the two study groups (p<0.05), neither before nor after administration of the drugs. The mean time required for pain relief in morphine group was significantly lower than aminophylline+hyoscine group (5.9±1.6 vs. 11.1±1.6 minutes; p<0.001). Conclusion: Overall, our findings indicated that aminophylline + hyoscine combination was effective in reducing renal colic pain and there is no significant difference between this combination and morphine in terms of pain relief

Comparing the Analgesic Effect of Aminophylline and Hyoscine with Morphine on Renal Colic: a Randomized Clinical Trial

Introduction: Although narcotics are effective for pain relief in these patients, they have little impact on the underlying cause. Therefore, surveys have been conducted to find more effective agents. Objective: This study conducted to compare the analgesic effect of aminophylline and hyoscine combination with morphine on renal colic patients. Methods: This double-blind clinical trial was conducted on patients with renal colic caused by urinary tract stones. Subjects were selected via convenience sampling method. Patients were randomly divided into two groups based on whether they received aminophylline + hyoscine or morphine. Before drug administration, one researcher was asked to measure the pain of the patients using Graduated Numbered Visual Analogue Scale (GN-VAS). Afterward, 20 mg of hyoscine along with 3 mg/kg of aminophylline in 100 cc normal saline was injected during 10 minutes into patients in the one group, whereas 0.1 mg/kg of morphine was intravenously with 100 cc normal saline to align two groups, administered to the subjects in another group. Half an hour after the administration of drugs, pain was measured for the second time. Vital signs and side effects were all recorded. Results: In this study, 95 patients (47 patients in the aminophylline+hyoscine group and 48 patients in the morphine group) remained in the trial until the end. The difference in sex distribution(p=0.227) and age(p=0.680) of the two groups was not statistically significant. Median of pain intensity was not significantly different between the two study groups (p<0.05), neither before nor after administration of the drugs. The mean time required for pain relief in morphine group was significantly lower than aminophylline+hyoscine group (5.9±1.6 vs. 11.1±1.6 minutes; p<0.001). Conclusion: Overall, our findings indicated that aminophylline + hyoscine combination was effective in reducing renal colic pain and there is no significant difference between this combination and morphine in terms of pain relief

Analysis of Root Causes of Major Process Accident in Town Border Stations (TBS) using Functional Hazard Analysis (FuHA) and Bow tie Methods

Background and objective: To control and prevention of accidents, attention to root causes of accident occurrence is very important. Safety risk of process units located in metropolis, must be always under control and in accordance with risk acceptance criteria of the community. In this regard, the purpose of this study is identification of functional failures, root cause analysis and incident outcomes arising from gas release in the Town Border Stations (TBS). Materials and method: Using at the same time of both methods the Functional Hazard Analysis (FuHA) and Failure Mode & Effect Analysis (FMEA), identification of the failure locations and qualitative risk analysis were carried out. For identification and analysis of the causes accident, Bow tie analysis method was also used. Results: Occurrence probability of identified top events was 0.71 and its failure rate was 1.24 per year. Unsafe behavioral (FP=0.36, &lambda=0.446) and mechanical causes (FP= 0.133, &lambda= 0.142) had highest and lowest the contribution in the top event occurrence. Vapor cloud explosion (VCE) had the highest probability (0.261) and failure rate (0.243) among the all identified incidents outcomes. Conclusion: Prevention of the root causes and attention to the human factors have the considerable contribution in accident control in the process units. In the combined approach used in present study, if are considered to be, the barriers role against of the root causes and incident outcomes occurrence, it could be an appropriate approach for identification of root causes and control of the hazards process

Assessing the Reliability of the City Gate Station Using Monte Carlo Simulation

Introduction: Reliability is always of particular importance in system design and planning; thus, improving reliability is among the approaches for achieving a safe system. Simulation methods are widely used in system reliability assessment. Therefore, this study aims to assess the reliability of the City Gate Gas Station (CGS) using Monte Carlo Simulation (MCS). Material and Methods: This descriptive and analytical study was conducted in one of the CGSs of North Khorasan Province in 2021. The CGS process was carefully examined and its block diagram was plotted. Then, failure time data of CGS equipment were collected over 11 years and time between failures of subsystems was calculated. The failure probability distribution function of subsystems was determined using Easy Fit software and Kolmogorov-Smirnov test. Moreover, subsystems’ reliability was estimated by MCS. Finally, station reliability was calculated considering the series-parallel structure of the CGS. Results: The results revealed that the failure probability density distribution function of CGS subsystems was based on gamma and normal functions. The reliabilities of filtration, heater, pressure reduction system, and odorize were calculated as 0.97, 0.987, 0.98, and 0.992 respectively, and their failure rates were 0.000003477, 0.0000014937, 0.0000023062, and 0.0000009169 failures per hour respectively. The station reliability was calculated as 0.93. Conclusion: The failure probability distribution function and reliability assessment of subsystems were determined by data modeling and MCS respectively. Filtration and pressure reduction systems had the highest failure rate and required a proper maintenance program

AcciMap-Based Development of a Dedicated Approach for Marine Accident Analysis

Introduction: Iran has the most extensive maritime transport fleet in the Middle East, with 2700 km of water border with other countries in the region. However, the complex and hazardous marine environment has turned this advantage into a disadvantage. On the other hand, technological advancement has added to the complexity. Thus, new accident analysis tools should be developed to bring unity to marine casualty analysis and improve the analyst’s power of discovery from incident information. The current project aims to develop a specialized AcciMap-based marine accident investigation method. Material and Methods: The primary stages of this applied descriptive study include data collection, method development, and validation. The necessary information about the factors leading to marine accidents was initially gathered through a review of previous studies, expert interviews, and analysis of actual cases. The AcciMap technique was then partially developed, and marine experts approved the designed model. Results: This study’s results included an AcciMap model established on three levels: external influences (national and international), intra-organizational factors, and environmental/individual conditions and individual activities. Whereas external factors (international and national) are categorized into three main layers, two sublayers, and 13 secondary sublayers, intra-organizational factors are categorized into two main layers, 11 sublayers, and 35 secondary sublayers, and environmental/individual conditions and individual activities are organized in one main layer, three sublayers, and 11 secondary sublayers. Conclusion: The developed approach can identify flawed levels and determine who is responsible for implementing corrective action. Because it includes emerging components that are effective in accidents, the method used in this study can better examine data from marine accidents

Safety analysis of process systems using Fuzzy Bayesian Network (FBN)

none4siQuantitative risk assessment (QRA) has played an effective role in improving safety of process systems during the last decades. However, QRA conventional techniques such as fault tree and bow-tie diagram suffer from drawbacks as being static and ineffective in handling uncertainty, which hamper their application to risk analysis of process systems. Bayesian network (BN) has well proven as a flexible and robust technique in accident modeling and risk assessment of engineering systems. Despite its merits, conventional applications of BN have been criticized for the utilization of crisp probabilities in assessing uncertainty. The present study is aimed at alleviating this drawback by developing a Fuzzy Bayesian Network (FBN) methodology to deal more effectively with uncertainty. Using expert elicitation and fuzzy theory to determine probabilities, FBN employs the same reasoning and inference algorithms of conventional BN for predictive analysis and probability updating. A comparison between the results of FBN and BN, especially in critically analysis of root events, shows the outperformance of FBN in providing more detailed, transparent and realistic results.mixedZarei, Esmaeil; Khakzad, Nima; Cozzani, Valerio; Reniers, GenserikZarei, Esmaeil; Khakzad, Nima; Cozzani, Valerio; Reniers, Genseri