scholarly journals Agent Based Risk Assessment of Fire Safety Systems with Automated Event Tree Analysis

2012 ◽  
Vol 31 (3) ◽  
pp. 87-97
Author(s):  
Michael Delichatsios ◽  
Farid Akashah ◽  
Jianping Zhang
Keyword(s):  
Risk Assessment ◽  
Fire Safety ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Agent Based ◽  
Safety Systems

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.

DAM RISK ASSESSMENT USING THE EVENT TREE ANALYSIS AND BAYESIAN NETWORKS

2019 ◽  
Author(s):  
RAFAE ANTONIO BRISEÑO-RAMIRO ◽  
VÍCTOR HUGO ALCOCER-YAMANAKA ◽  
ADRIÁN PEDROZO-ACUÑA ◽  
JOSÉ AGUSTIN BREÑA-NARANJO ◽  
RAMÓN DOMÍNGUEZ-MORA
Keyword(s):  
Risk Assessment ◽  
Bayesian Networks ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Dam Risk

scholarly journals Quantitative Risk Assessment of Biogas Plant – Determination of Assumptions and Estimation of Selected Top Event

2019 ◽  
Author(s):  
Petr Trávníček ◽  
Luboš Kotek ◽  
Tomáš Koutný ◽  
Tomáš Vítěz
Keyword(s):  
Risk Assessment ◽  
Chemical Industry ◽  
Fault Tree Analysis ◽  
Quantitative Risk Assessment ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Hazardous Chemical ◽  
Biogas Plants

Biogas plants are a specific facility from the QRA (Quantitative Risk Assessment) methodologies' point of view, especially in the case of the determination of the event frequency of accident scenarios for biogas leakage from a gas holder and subsequent initiation. QRA methodologies determine event frequencies for different types of accident events related to vessels made of steel. Gas holders installed at biogas plants are predominantly made of other materials and are often integrated with the fermenter. It is therefore a specific type of gas holder, differing from that which is commonly used in the chemical industry. In addition, long-term experience is not available for the operation of biogas plants, unlike in the chemical industry. The event frequencies listed in the QRA methodologies are not relevant for the risk assessment of biogas plants. This work is focused on setting the prerequisites for QRA of biogas storage, including for example: information on hazardous chemical substances occurring at biogas plants, their classification, and information on the construction of integrated gas holders. For the purpose of the work, a scenario was applied where the greatest damage (to life or property) is expected. This scenario is the leakage of the total volume of hazardous gas substance from the gas holder and subsequent initiation. Based on this information, a "tree" was processed for "Fault Tree Analysis" (FTA), and frequencies were estimated for each event. Thereafter, an "Event Tree Analysis" was carried out. This work follows up on a discussion by experts on the determination of scenario frequencies for biogas plants that was conducted in the past.

scholarly journals IT RISK IDENTIFICATION AND ASSESSMENT METHODOLOGY

2017 ◽  
Vol 2 ◽  
pp. 124
Author(s):  
Oskars Podziņš ◽  
Andrejs Romānovs
Keyword(s):  
Risk Assessment ◽  
Impact Analysis ◽  
Risk Identification ◽  
The Other ◽  
Qualitative Assessment ◽  
Event Tree ◽  
Structured Interviews ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Other Hand

There are numerous methods for risk identification and risk assessment phases. Which for risk identification includes historical and systematic approach and inductive or theoretical analysis. One of the main reasons why risk identification is very helpful is that it provides justification in many cases for any large IT investment and other large undertakings. Without it organization probably wouldn’t be able to come to conclusion. Also in this phase business recognize the threats, vulnerabilities, and assets associated with its IT systems. Together with risk assessment phase risk management specialist is responsible for determining asset value, what's the value of the asset business is protecting, and risk acceptance level. Risk assessment on the other hand examines impact or consequence, as well as examines and evaluates the likelihood or probability of that adverse event happening. Risk assessment includes methods like Bayesian analysis, Bow Tie Analysis, brainstorming or structured interviews, business impact analysis, cause and consequence, cause-and-effect analysis, Delphi method, event tree analysis, fault tree analysis, hazard analysis, hazard and operational studies, and finally structured what if technique or SWIFT process. Risk assessment has two distinctive assessment types- quantitative and qualitative assessment. Quantitative assessment tries to put a monetary value on all risks. Qualitative assessment on the other hand rather look at it from a range of values like low, medium, high. The results of these phases are going to be documented in the risk assessment report and reported to senior management.

Risk Assessment of Hydrogen Production System by Dimethyl Ether Steam Reforming With the Use of Nuclear Power

2009 ◽  
Author(s):  
Kazuo Koguchi ◽  
Shigeo Kasai ◽  
Makoto Takahashi ◽  
Toshio Wakabayashi
Keyword(s):  
Risk Assessment ◽  
Heat Exchanger ◽  
Hydrogen Production ◽  
Dimethyl Ether ◽  
Steam Reforming ◽  
Nuclear Power ◽  
Average Frequency ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis

Hydrogen is regarded as a clean fuel because it does not pollute when burned with air. In the case of commercial use, there is a need to research how to produce hydrogen more efficiency and large scale. Although there are some methods of hydrogen production, it can be considered that the heat of the nuclear reactor is promising method. In the recent studies on the hydrogen production with nuclear power, there has focused on the technical issues. Therefore, the object in this paper is to perform the risk assessment for a system of hydrogen production plant by Dimethyl Ether (DME) steam reforming with the use of nuclear power. First, one of the suitable systems with the DME steam reforming plant was selected PWR. A FMEA (Failure Mode and Effects analysis) was performed to identify initiating events. After identifying initiating events, event tree analysis (ETA) was performed to quantify the average frequency of an accident at this system. The result of the PSA, the safety of DME steam reforming plant with nuclear power depends on a rupture of reformer and heat exchanger between hydrogen and DME by the result of FMEA. Event tree analysis shows that the average frequency of hydrogen or DME explosion is 7.7×10−7 year−1 in the case of the rupture of the reformer and 1.9×10−8 year−1 in the case of the break of the heat exchanger.

scholarly journals Risk Assessment of a Battery-Powered High-Speed Ferry Using Formal Safety Assessment

Safety ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 39
Author(s):  
Haibin Wang ◽  
Evangelos Boulougouris ◽  
Gerasimos Theotokatos ◽  
Alexandros Priftis ◽  
Guangyu Shi ◽  
...  
Keyword(s):  
Risk Assessment ◽  
High Speed ◽  
Safety Assessment ◽  
Assessment Procedure ◽  
Event Tree ◽  
Maritime Industry ◽  
Event Tree Analysis ◽  
Safety Level ◽  
Tree Analysis ◽  
Formal Safety Assessment

Fully electric ships have been widely developed, investigated and evaluated by the maritime industry as a potential solution to respond to the emissions control required according to the International Maritime Organization (IMO). This study aims at presenting a novel approach to evaluate the safety level of a battery-powered high speed catamaran. Following the Formal Safety Assessment procedure, the risk assessment of the considered ship was conducted leading to the identification of the involved hazards along with the estimation of their frequency and consequences thus allowing for the identification of the most severe hazards. Fault tree analysis is carried out for and the identified top events followed by an event tree analysis to estimate the risk and safety level of the vessel. Furthermore, a cost-benefit assessment is conducted to evaluate the financial impact of selected risk control options. The derived results indicate that the application of battery power systems for high speed ferries exhibits low and acceptable accident frequencies. It is also supported the current regulation to carry out mandatory risk assessment for battery-powered ships.

Risk mitigation in unstabilized approach with fuzzy Bayesian bow-tie analysis

2020 ◽  
Vol 92 (10) ◽  
pp. 1513-1521
Author(s):  
Caner Acarbay ◽  
Emre Kiyak
Keyword(s):  
Risk Assessment ◽  
Performance Indicator ◽  
Risk Mitigation ◽  
Assessment System ◽  
Assessment Process ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Content Type ◽  
Bow Tie

Purpose Stable approach concept has great importance for the safe operation of an airline during the approach and landing phases. The purpose of this study is to analyse the unstabilized approaches with bow-tie method and determine the threats that may cause risk in an unstable approach. Design/methodology/approach In this study, risk assessment of the unstabilized approaches is carried out by using fuzzy bow-tie method and Bayesian networks. Bow-tie method is the combination of event tree analysis and fault tree analysis. Bayesian network is used in the analysis to see interrelationship of basic and intermediate events as well as to update posterior probabilities. Finally, analysis results are verified by the safety performance indicator values. Findings In this study, the probabilistic values of the numerical model presented by the risk assessment system for risks were calculated using the fuzzy bow-tie method. Thus, the risk assessment system has been transformed into a structure that can be expressed in a probabilistic manner, and the relationship of the risks within the system has been examined and the effect of a possible change on the risk value has been found to be prevalent. Originality/value The bow-tie model is widely applied to assess the risks in aviation. Obtaining prior probabilities is not always possible in the risk assessment process. In this paper, innovative fuzzy bow-tie method is used to assess the risks to overcome the lack of prior probability problem in aviation operations.

Sign in / Sign up

Export Citation Format

Share Document