A Survey of Early Design Risk and Reliability Methods and Their Impediments to Move Into Practice

2012 ◽  
Author(s):  
Bryan M. O’Halloran ◽  
Robert B. Stone ◽  
Irem Y. Tumer
Keyword(s):  
Research Methods ◽  
Failure Modes ◽  
Fault Tree Analysis ◽  
Event Tree ◽  
Reliability Engineering ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Early Design ◽  
Reliability Methods ◽  
Reliability Block Diagrams

This research surveys early design risk and reliability methodologies and discusses the impediments of moving these research methods into practice. Reliability engineering techniques exist primarily to help engineers better meet the needs of customers by extending design life and reducing the number of failures observed throughout the intended life. These efforts look at system components and functions, critical events, failure modes, and system characteristics to assess risk and reliability during the early design phase before detailed design has begun. Surveying early design reliability to identify underdeveloped areas of research contributes to an ongoing effort to increase the presence of reliability engineering earlier in design. In addition, this improves a researchers’ understanding of key consideration that need to be addressed during the development of the research so that it is useful in practice. Throughout this paper, four fundamental methods are identified and described including Event Tree Analysis, Fault Tree Analysis, Reliability Block Diagrams, and Failure Modes and Effects Analysis. Related methods, or those developed to solve limitations of the fundamental methods, are presented and compared to the fundamental methods. Finally, the impediments of moving research methods into practice are surveyed, then discussion is provided for the factors that improve this transition of research.

FUNDAMENTALS OF THE DEMPSTER-SHAFER THEORY AND ITS APPLICATIONS TO RELIABILITY MODELING

2007 ◽  
Vol 14 (06) ◽  
pp. 579-601 ◽  
Author(s):  
UWE KAY RAKOWSKY
Keyword(s):  
Failure Modes ◽  
Fault Tree Analysis ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Reliability Modeling ◽  
Tree Analysis ◽  
Dempster Shafer Theory ◽  
Safety And Reliability ◽  
Shafer Theory ◽  
Criticality Analysis

The Dempster-Shafter Theory is well-known for its usefulness to express uncertain judgments of experts. This contribution shows how to apply the calculus to safety and reliability modeling, especially to expert judgment; Failure Modes, Effects, and Criticality Analysis; Event Tree Analysis, Fault Tree Analysis, and Reliability Centered Maintenance. Including a tutorial introduction to the Dempster-Shafer Theory, the differences between the Probability and the Dempster-Shafer Theory are discussed widely.

Risk management and employment of advanced methods of risk estimation

2020 ◽  
pp. 52-57
Author(s):  
A.S. Abdullaev ◽  
◽  
N.A. Abbasov ◽  
Keyword(s):  
Risk Management ◽  
Failure Modes ◽  
Risk Estimation ◽  
Fault Tree Analysis ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Effect Analysis ◽  
Tree Analysis ◽  
Logical Connection ◽  
Pros And Cons

The paper studies the methods applied in risk management and estimation. The brainstorming techniques, Delphi, the method of event tree analysis (ETA) and fault tree analysis (FTA), failure modes and effect analysis (FMEA), hazard and operability study are wide used. The pros and cons of risk management methods applied in world practice by leading companies were analysed. As a technique based on the study of logical connection between the hazardous events, “Tree event” method has its advantages. At the same time, the failure modes and effect analysis differs with simplicity and accessibility. It was defined that this technique is used as one of the most important tools in risk management almost in all spheres including petrochemistry and power economy. It is recommended to use HAZOP method in the analysis of project solutions and for risk estimation in later design stages. It is pointed out that in the context of improvement of risk management system, more qualitative risk estimation, the employment of advanced methods plays a significant role for goal achievement in the company and project decision-making as well.

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 Ανάπτυξη και εφαρμογή μεθοδολογίας εκτίμησης διακινδύνευσης σε ναυπηγεία

2015 ◽  
Author(s):  
Νικόλαος Φραγκιαδάκης
Keyword(s):  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Fault Tree Analysis ◽  
Quantitative Risk Assessment ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Inference System ◽  
Tree Analysis ◽  
Neuro Fuzzy ◽  
Bow Tie

Στόχος αυτής της διατριβής είναι η δημιουργία μοντέλου που θα οδηγεί σε μια Ποσοτική Εκτίμηση Επαγγελματικής Διακινδύνευσης (Quantitative Risk Assessment, QRA) εργαζομένων στην ναυπηγική και ναυπηγοεπισκευαστική βιομηχανία με γνώμονα το εργατικό ατύχημα, επιχειρώντας να συμβάλλει στην αντιμετώπιση ενός προβλήματος που έχει σημαντικές κοινωνικές αλλά και οικονομικές διαστάσεις. Ακολουθήθηκαν δύο ανεξάρτητοι οδοί που συμπληρώνουν η μία την άλλη.Η πρώτη οδός οδήγησε στην ανάπτυξη ενός Αναλυτικού Μοντέλου, ικανό να περιγράφει τους μηχανισμούς σύνδεσης μεταξύ αιτίου- αιτιατού - συνεπειών εργατικών ατυχημάτων σε ναυπηγικές εργασίες και να οδηγεί υπό προϋποθέσεις σε μια ολοκληρωμένη QRA. Το μοντέλο στηρίχθηκε στον εντοπισμό και στην αξιολόγηση των πηγών κινδύνου, καθώς και άλλων επιβαρυντικών παραγόντων μέσα στο εργασιακό περιβάλλον ενός ναυπηγείου. Τεχνικές χρήσης επαγωγικών μοντέλων όπως τα δέντρα γεγονότων (Event Tree Analysis, ETA) και τα δέντρα σφαλμάτων (Fault Tree Analysis, FTA) χρησιμοποιήθηκαν. Τα επαγωγικά μοντέλα συνδέθηκαν τελικά σε μια ολοκληρωμένη δομή “BOW TIE”, στην οποία απεικονίζεται σαφώς η σχέση των γενεσιουργών αιτιών και των επιβαρυντικών παραγόντων που δύναται να οδηγήσουν στη δημιουργία ενός συμβάντος, καθώς και η πορεία από το συμβάν στις πιθανές συνέπειες μέσω των αμβλυντικών παραγόντων που συνθέτουν τα ανεξάρτητα επίπεδα προστασίας (Independent Layers of Protection, ILPs). Έτσι παρίστανται οι παράγοντες που συγκροτούν τη διακινδύνευση, δηλαδή η πιθανότητα ενός συμβάντος αφενός και οι πιθανές συνέπειες αφετέρου. Για την καλύτερη κατανόηση και τεκμηρίωση του μοντέλου διενεργήθηκαν τεχνικές ανάλυσης και αναγνώρισης κινδύνου για συγκεκριμένες χαρακτηριστικές περιπτώσεις (HAZID), κατασκευάστηκαν διαγράμματα ροής για αυτές τις περιπτώσεις και αριθμητικό παράδειγμα υπολογισμού της διακινδύνευσης για μια εκ των περιπτώσεων.Η δεύτερη οδός οδήγησε στην δόμηση ενός έμπειρου συστήματος, στηριζόμενου σε κανόνες ασαφούς λογικής και ασαφούς συμπερασμού, που χρησιμοποιεί την παρεχόμενη πληροφορία από δεδομένα εργατικών ατυχημάτων στη ναυπηγική βιομηχανία, τα οποία έχουν συγκεντρωθεί από ναυπηγοεπισκευαστικές μονάδες, μέσω της χρήσης στατιστικής ανάλυσης και με τη χρήση υπολογιστικών τεχνικών soft computing. Επιλέχθηκε η δημιουργία ενός «Ασαφούς Συστήματος Συμπερασμού» (Fuzzy Inference System, FIS) που στηρίζεται στα προσαρμοζόμενα νευρωνικά δίκτυα (Adaptive Neural Networks, AN). Τα καταγεγραμμένα δεδομένα στοιχεία υπέστησαν στατιστική επεξεργασία και καθορίστηκαν οι παράμετροι και τα δεδομένα για την τροφοδότηση, την εκπαίδευση και τον έλεγχο των αποτελεσμάτων του Προσαρμοζόμενου Νευρωνικού Ασαφούς Συστήματος Συμπερασμού (Adaptive Neuro-Fuzzy Inference System ANFIS).Το μοντέλο “BOW TIE” αποδείχθηκε ικανό να οδηγήσει σε ποιοτικά συμπεράσματα όπως ο εντοπισμός των πηγών κινδύνου, των επιβαρυντικών αλλά και των αμβλυντικών παραγόντων αλλά και να τεκμηριώσει ποσοτικά κάθε μέτρο βελτίωσης της ασφάλειας με στόχο τη μείωση της διακινδύνευσης.Το μοντέλο ANFIS αποδεδείχθηκε μια εφικτή μέθοδος προσομοίωσης της πολύπλοκης σχέσης μεταξύ των παραμέτρων που εμπλέκονται σε ένα εργατικό ατύχημα στη ναυπηγική βιομηχανία, εκμεταλλευόμενο ήδη υπάρχοντα και κατάλληλα στατιστικά επεξεργασμένα ιστορικά στοιχεία εργατικών ατυχημάτων, αποτελώντας ένα εργαλείο ικανό να κάνει προβλέψεις και να οδηγεί σε ασφαλή συμπεράσματα, σε μικρό υπολογιστικό χρόνο.

Semi-Supervised Machine Learning Algorithms for Classifying the Imbalanced Protocol Flows

2014 ◽  
Vol 536-537 ◽  
pp. 809-814
Author(s):  
Lin Lin Li ◽  
Xiao Yi Zhang ◽  
Xia Zhang ◽  
Qing Li
Keyword(s):  
Fault Tree Analysis ◽  
Machine Learning Algorithms ◽  
Supervised Machine Learning ◽  
Event Tree ◽  
Level Crossing ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Minimal Cut Set ◽  
Risk Event ◽  
Precautionary Measures

The collision that between a car and a train is the main type of accidents in the case railway level-crossing, which is proved by the arrangement diagram analysing. The fault tree analysis and the event tree analysis are used to assess the level of the risk of the level-crossing quantificationally. Some conclusions can be drawn: the collision of the railway level-crossing that between a car and a train will happen 2.552 in a year, which can bring 0.061 equivalent fatalities. This paper puts forward some precautionary measures that based on the minimal cut set of the collision of the accident and the most probable or the highest risk event.

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.

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.

Operations Research and Archaeology

1991 ◽  
Vol 56 (1) ◽  
pp. 19-35 ◽  
Author(s):  
Peter Bleed
Keyword(s):  
Great Plains ◽  
Operations Research ◽  
Conceptual Models ◽  
Fault Tree Analysis ◽  
Event Tree ◽  
Archaeological Remains ◽  
Economic Activities ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Analysis Models

Operations research is the systematic study of resource utilization through the manipulation of conceptual models. Used most often by engineers and managers, these models also have potential application in archaeology. Event tree analysis, which models multipart systems with a number of potential consequences resulting from a series of events, makes it possible to analyze artifact-production processes or the operation of complex economic activities such as hunting. Fault tree analysis models the interactions of factors that can cause a technological system to fail. It offers a framework for the interpretation of archaeological remains such as flintlock firearm parts at Indian and Euroamerican sites of the Great Plains.

Decision Making for Safety Assessment of Mobile Mooring System

2013 ◽  
Vol 61 (3) ◽  
Author(s):  
Silvianita S. ◽  
Mohd Faris Khamidi ◽  
V. J. Kurian
Keyword(s):  
Decision Making ◽  
Safety Assessment ◽  
Fault Tree Analysis ◽  
Inductive Method ◽  
Mooring System ◽  
Offshore Platforms ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Floating Structures

Floating structures use mooring system for station keeping in any water depths. Mooring system is a vital component for the safety of floating structures. Mooring accidents can cause serious injury or damage to the vessel, and hence it is necessary to establish a systematic risk–based decision making for safety assessment of mobile mooring system. This study uses the mobile mooring system of a semi submersible pipe laying barge as a case study. The aim of this study is to develop a Methodology for Investigation of Critical Hazards (MIVTA), which is carried out by the development of preliminary risk analysis using HAZOP (Hazard and Operability), to generate the root causes using FTA (Fault Tree Analysis) and to construct the sequence of the consequences using ETA (Event Tree Analysis). HAZOP is a systematic examination of a system helpful to identify and evaluate the risks related to accidents/incidents in mooring system. FTA is a deductive method useful to generate the potential causes of mooring system failure into undesired events. ETA is an inductive method helpful to define all possible outcomes of accidental events. This study conducts risk-based decision making coupled with the knowledge of the experts of mooring system to identify the root causes, to evaluate the frequency of failure and to classify their class of consequences. This study provides a systematic methodology guideline for the risk–based decision making useful to identify the risk of accidents occurring in offshore platforms.

Human Factor in the Life Cycle and Safety of Machines and Pipelines

2003 ◽  
Author(s):  
Sviatoslav A. Timashev
Keyword(s):  
Risk Analysis ◽  
Human Error ◽  
Human Factor ◽  
Fault Tree Analysis ◽  
Qualitative Assessment ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Human Reliability Analysis ◽  
Tree Analysis ◽  
Main Components

The paper is an overview (using references listed below) and describes the main components, means and methods of a holistic and quantitative human reliability analysis (QHRA) using quantitative values of human error when performing Fault Tree Analysis (FTA) and Event Tree Analysis (ETA). It also deals with qualitative assessment of the influence of the human factor (HF) reliability on safety and risk analysis of potentially dangerous man-machine-structures-environment systems (PDMMSES). Qualitative risk analysis of such man-machine-structures-environment (MMSE) systems is based on using the event-decision technique in combination with a generalized socio-psychological model of the decision making person (DMP). Three types of DMP’s are considered: members of maintenance/repair crews, diagnosticians and different rank DMP’s that operate or own the PDMMSES.

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