Quantitative assessment of risks on construction projects using fault tree analysis with hybrid uncertainties

2019 ◽  
Vol 19 (1) ◽  
pp. 48-70 ◽  
Author(s):  
Shahab Shoar ◽  
Farnad Nasirzadeh ◽  
Hamid Reza Zarandi
Keyword(s):  
Risk Analysis ◽  
Uncertainty Analysis ◽  
Fuzzy Set ◽  
Fault Tree ◽  
Analysis Method ◽  
Content Type ◽  
Quantitative Risk Analysis ◽  
Probability Of Occurrence ◽  
Hybrid Uncertainty ◽  
The Impact

Purpose The purpose of this paper is to present a fault tree (FT)-based approach for quantitative risk analysis in the construction industry that can take into account both objective and subjective uncertainties. Design/methodology/approach In this research, the identified basic events (BEs) are first categorized based on the availability of historical data into probabilistic and possibilistic. The probabilistic and possibilistic events are represented by probability distributions and fuzzy numbers, respectively. Hybrid uncertainty analysis is then performed through a combination of Monte Carlo simulation and fuzzy set theory. The probability of occurrence of the top event is finally calculated using the proposed FT-based hybrid uncertainty analysis method. Findings The efficiency of the proposed method is demonstrated by implementing in a real steel structure project. A quantitative risk assessment is performed for weld cracks, taking into account of both types of uncertainties. An importance analysis is finally performed to evaluate the contribution of each BE to the probability of occurrence of weld cracks and adopt appropriate response strategies. Research limitations/implications In this research, the impact of objective (aleatory) dependence between the occurrences of different BEs and subjective (epistemic) dependence between estimates of the epistemically uncertain probabilities of some BEs are not considered. Moreover, there exist limitations to the application of fuzzy set rules, which were used for aggregating experts’ opinions and ranking purposes of the BEs in the FT model. These limitations can be investigated through further research. Originality/value It is believed that the proposed hybrid uncertainty analysis method presents a robust and powerful tool for quantitative risk analysis, as both types of uncertainties are taken into account appropriately.

Artificial intelligence treating the problem of uncertainty in quantitative risk analysis (QRA)

2019 ◽  
Vol 18 (1) ◽  
pp. 40-54
Author(s):  
Mohamed Seddik Hellas ◽  
Rachid Chaib ◽  
Ion Verzea
Keyword(s):  
Artificial Intelligence ◽  
Fuzzy Logic ◽  
Risk Analysis ◽  
Lung Damage ◽  
Whole Body ◽  
Individual Risk ◽  
Content Type ◽  
Quantitative Risk Analysis ◽  
Accident Scenario ◽  
Imperfect Knowledge

Purpose Nowadays, artificial intelligence computational methods, such as knowledge-based systems, neural networks, genetic algorithms and fuzzy logic, have been increasingly applied to several industrial research studies, the purpose of this paper is to study the contribution of fuzzy and possibilistic techniques to quantitative risk analysis (QRA) in the presence of imperfect knowledge about the occurrence and consequences of accidental phenomena. Design/methodology/approach To solve the problem of uncertainties related to the elements of the accident scenario such as the frequency and severity of the consequences, the authors used fuzzy logic. Using this type of analysis, it is possible to visualize the contours of the dead or fuzzy injury by fireball thermal effect (first- and second-degree burn, death) and lesions caused by vapor cloud explosion overpressure (lung damage, eardrum rupture, head impact, whole-body displacement). The frequency and severity of fuzzy results are calculated by extended multiplication using the alpha-cuts method. Findings This research project aims to reflect the real situation in the in Amenas industrial area (SONATRACH company), specifically the liquefied petroleum gas storage tank On-Spec 05-V-411A, to deal with this type of risk. Using this analysis allows us to estimate the fuzzy individual risk using the approach of fuzzy logic to treating this uncertainty in the parameter information of accident scenarios. This index individuel risk (IR) was evaluated against the criterion of acceptability and then used for decision-making in the field of industrial risk analysis and evaluation. Originality/value The originality of the work is to identify the weak points of the classical QRA to solve the problem of the uncertainties related to the elements of the accident scenario such as the frequency and severity of the consequences to visualize the fuzzy risk contours. On the one hand and the development of software to calculate the probability of death by the overpressure effect and classify the most sensitive organs on the other hand. Given the importance of this study, it can be generalized for similar sites in the region.

Study and Analyse Hydraulic System of a Boat by Using Risk Analysis Method

2012 ◽  
Vol 542-543 ◽  
pp. 119-123
Author(s):  
Ning Li ◽  
Yuan Gu ◽  
Shi Long Xing ◽  
Lu Li
Keyword(s):  
Risk Analysis ◽  
Failure Probability ◽  
Hydraulic System ◽  
Fault Tree ◽  
Minimum Cut ◽  
Analysis Method ◽  
Reliability Method ◽  
Cut Set ◽  
Working Out

Analysis hydraulic system of a boat by using reliability method, setting up the fault tree, confirming the minimum cut set, working out the failure probability and the criticality importance of all base events. The datum is provided for security and maintainability.

scholarly journals Impact of convection on thermographic analysis of silver based thermal joints

2020 ◽  
Vol 32 (4) ◽  
pp. 241-246
Author(s):  
Krzysztof Jakub Stojek ◽  
Jan Felba ◽  
Johann Nicolics ◽  
Dominik Wołczyński
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Energy Loss ◽  
Thermal Resistance ◽  
Analysis Method ◽  
Content Type ◽  
Heat Transfer Efficiency ◽  
Lowered Pressure ◽  
Thermographic Analysis ◽  
The Impact

Purpose This paper aims to develop thermal analysis method of thermal joints characterization. The impact on convection on thermal resistance analysis with use thermography for silver-based thermal joints were investigated for non-metallized and metalized semiconductor surfaces. Heat transfer efficiency depends on thermal conductivity; radiation was used to perform thermographic analysis; the convection is energy loss, so its removing might improve measurements accuracy. Design/methodology/approach Investigation of thermal joints analysis method was focused on determination of convection impact on thermal resistance thermographic analysis method. Measuring samples placed in vacuum chamber with lowered pressure requires transparent window for infrared radiation that is used for thermographic analysis. Impact of infrared window and convection on temperature measurements and thermal resistance were referred. Findings The results showed that the silicon window allowed to perform thermal analysis through, and the convection was heat transfer mode which create 15% energy loss. Originality/value It is possible to measure thermal resistance for silver-based thermal joints with convection eliminated to improve measurements accuracy.

A comparative study of the evolution of vulnerabilities in IT systems and its relation to the new concept of cloud computing

2014 ◽  
Vol 20 (4) ◽  
pp. 409-433 ◽  
Author(s):  
Issam Kouatli
Keyword(s):  
Cloud Computing ◽  
Risk Analysis ◽  
Comparative Study ◽  
New Technology ◽  
Business Environment ◽  
Cloud Services ◽  
Content Type ◽  
It Systems ◽  
Weighted Score ◽  
The Impact

Purpose – The purpose of this paper is to classify and categorize the vulnerability types emerged with time as information technology (IT) systems evolved. This comparative study aims to compare the seriousness of the old well-known vulnerabilities that may still exist with lower possibility of happening with that of new technologies like cloud computing with Mobility access. Cloud computing is a new structure of IT that is becoming the main part of the new model of business environment. However, issues regarding such new hype of technology do not come without obstacles. These issues have to be addressed before full acceptability of cloud services in a globalized business environment. Businesses need to be aware of issues of concerns before joining the cloud services. This paper also highlights these issues and shows the comparison table to help businesses with appropriate decision-making when joining the cloud. Design/methodology/approach – A historical review of emerged vulnerabilities as IT systems evolved was conducted, then these vulnerabilities were categorized into eight different categories, each of which composed of multiple vulnerability types. Simple scoring techniques were used to build a “risk” analysis table where each vulnerability type was given a score based on availability of matured solution and the likeliness of happening, then in case of vulnerability type, another score was used to derive the impact of such vulnerability. The resulted weighted score can be derived from the multiplication of likeliness to happen score with that of its impact in case it did happen. Percentage of seriousness represented by the percentage of the derived weighted score of each of the vulnerabilities can then be concluded. Similar table was developed for issues related to cloud computing environment in specific. Findings – After surveying the historical background of IT systems and emerged vulnerabilities as well as reviewing the common malicious types of system vulnerabilities, this paper identifies 22 different types of vulnerability categorized in eight different categories. This comparative study explores amount of possible vulnerabilities in new technology like cloud computing services. Specific issues for cloud computing were also explored and a similar comparative study was developed on these issues. The result of the comparative study between all types of vulnerabilities since the start of IT system development till today’s technology of cloud computing, shows that the highest percentage vulnerability category was the one related to mobility access as mobile applications/systems are relatively newly emerged and do not have a matured security solution(s). Practical implications – Learning from history, one can conclude the current risk factor in dealing with new technology like cloud computing. Businesses can realize that decision to join the cloud requires thinking about the issues mentioned in this paper and identifying the most vulnerability types to try to avoid them. Originality/value – A new comparative study and new classification of vulnerabilities demonstrated with risk analysis using simple scoring technique.

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