Application of fuzzy logic to fault tree and event tree analysis of the risk for cargo liquefaction on board ship

2020 ◽  
Vol 101 ◽  
pp. 102238 ◽  
Author(s):  
Emre Akyuz ◽  
Ozcan Arslan ◽  
Osman Turan
Keyword(s):  
Fuzzy Logic ◽  
Fault Tree ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Board Ship

Risk Assessment in Bridge Construction Projects Using Fault Tree and Event Tree Analysis Methods Based on Fuzzy Logic

2015 ◽  
Vol 1 (3) ◽  
Author(s):  
Gholamreza Abdollahzadeh ◽  
Sima Rastgoo
Keyword(s):  
Fuzzy Logic ◽  
Traditional Approach ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Mitigation Strategies ◽  
Fuzzy Arithmetic ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Risk Event

In this paper, interruption risk in construction activities of bridge projects is assessed in order to identify the main causes of its occurrence and also to determine the potential outcomes resulted from the risk occurrence. To do this, fault tree and event tree analysis (ETA) methods are applied. As the application of the traditional approach of these two methods is difficult in many cases due to limited access to information, fuzzy arithmetic can be considered as a useful tool. In this research, first, fault tree structure is created according to consequences resulted from the Delphi method. Then, the probability of risk occurrence is calculated by applying fault tree analysis (FTA) based on fuzzy logic. By establishing the structure of fault tree related to the failure risk of mitigation strategies, the main causes relating to failure of strategies are identified. The structure of the event tree is created using the obtained results; moreover, the expected monetary value (EMV) of risk event is computed. Finally, to validate the results obtained, a model is created by Monte Carlo simulation and then the results obtained by applying the two methods are compared. The EMV of the risk event evaluated in this paper is determined to be 9.93% of the project baseline cost.

scholarly journals Methodology for tunnel risk assessment using fault and event tree analysis

2021 ◽  
Author(s):  
Zlatko Zafirovski ◽  
Vasko Gacevski ◽  
Zoran Krakutovski ◽  
Slobodan Ognjenovic ◽  
Ivona Nedevska
Keyword(s):  
Risk Assessment ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Economic Consequences ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Geological Conditions ◽  
Hazard And Risk ◽  
Complex Solutions

The intense demand and construction of tunnels is accompanied by uncertainties. The reason for appearance of uncertainties are the complex solutions and conditions for these structures. Location and dimensions are becoming more challenging, and the construction is predicted in complexed geological conditions, leading to application of new approaches, methodologies and technologies by the engineers. Most of the uncertainties and unwanted events in tunnelling occur in the construction phase, which generally leads to economic consequences and time losses. For easier handling of the uncertainties, they should be anticipated and studied within a separate part of each project. One of the newer approaches to dealing with uncertainties is hazard and risk assessment and defining ways to deal with them i.e. management. Hazards and risks can be analysed qualitatively and quantitatively. The quantitative analysis, examines the causes and consequences in more detail way and gives explanation of the dependencies. With the quantitative approach, a more valuable information for decision-making can be provided. There are various models and methods used for the quantification of hazards and risks. This paper presents a methodology in which the fault tree analysis and event tree analysis are used in combination to obtain quantitative results. The fault tree analysis is used for assessment of various hazards and the different ways and reasons that cause them. The event tree analysis is a method for assessing the possible scenarios, which follow after a certain hazard i.e. the consequences that may occur in the project. These trees represent graphic models combined with a mathematical (probabilistic) model, which give the probability of occurrence of the risks.

scholarly journals RISK MANAGEMENT ON THE WARSHIP TASK OPERATIONS

JOURNAL ASRO ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 23
Author(s):  
Diksono Diksono ◽  
I Made Jiwa ◽  
Suparno Suparno
Keyword(s):  
Risk Mitigation ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Main Tool ◽  
Main Task ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Formal Safety Assessment ◽  
The Impact

ABSTRACT The main task of the Indonesia Navy is to enforce the law and maintain security in the territorial sea of national jurisdiction, so that the Indonesian Navy is required to have the main tool of weapons systems (Alutsista) are always ready to carry out the task. The frequent occurrence of accidents experienced by the Indonesian Warship (KRI). This reduces the ability of Warship in performing the task. The purpose of this research is to investigate the causes and effects of accidents, and seek risk mitigation that is considered appropriate. Formal Safety Assessment (FSA) is a structured and systematic methodology used for maritime safety analysis. The fault tree analysis is used to investigate the cause of marine accidents and the event tree analysis is used to determine the impact of an accident. The results of this study are FSA can be effectively applied in accident investigations, although the calculation of cost benefit analysis for warships can be ignored because the Warship task cannot be compared to the value of money.  Keywords: Task Operation, Warship, FSA, fault tree analysis, event tree analysis

scholarly journals Evaluation of the Level of Reliability in Hazardous Technological Processes

2020 ◽  
Vol 11 (1) ◽  
pp. 134
Author(s):  
Darja Gabriska
Keyword(s):  
Reliability Analysis ◽  
Failure Rate ◽  
System Reliability ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Entire System ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Technical Standards ◽  
Tree Analysis

In an automated systems environment is very important to predicted failures or unexpected situations to achieve system reliability. Failure of such systems can cause serious property damage, the environment, damage to human health or cause death. The essential task is to determine the tolerable and acceptable risk. The required level of risk for safety-critical systems can be achieved by using international technical standards and applying safety functions. Safety functions are implemented using an electrical/electronic/programmable electronics (E/E/PE) safety-related system. Technical standards offer the aspect of balancing risk tolerability according to the relevant, reliable safety functions. Based on the specific architecture of the whole system, it is possible to determine the maximum failure rate of the probability of failure on demand (PFDSYS) of the selected architecture. Subsequent application of reliability analysis using the event tree analysis (ETA) and fault tree analysis (FTA) methods can optimize the failure rate of the entire system. Application of reliability analysis using event tree analysis (ETA) and fault tree analysis (FTA) methods can only theoretically optimize the failure rate of the entire system with constant initial conditions and constant parameters of the reliability functions. The article proposes a new methodology for dynamic analysis of the state of system reliability as a function of the system operation time, maintenance frequency and system architecture. As a result of the methodology is a library of standard element architectures and simulation models which allows predicting and optimizing the reliability of E/E/PE safety-related systems.

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