All Outputs (65)

Calculation of the System Unavailability Measures of Component Importance Using the D2T2 Methodology of Fault Tree Analysis (2024)
Journal Article

A recent development in Fault Tree Analysis (FTA), known as Dynamic and Dependent Tree Theory (D2T2), accounts for dependencies between the basic events, making FTA more powerful. The method uses an integrated combination of Binary Decision Diagrams... Read More about Calculation of the System Unavailability Measures of Component Importance Using the D2T2 Methodology of Fault Tree Analysis.

Fault Tree Analysis Including Component Dependencies (2023)
Journal Article

Fault Tree analysis is not only the most common technique used in engineering practice for the estimation of system reliability, but is also a key tool shared between designers, analysts and regulators for safe operation and licensing purposes. In sp... Read More about Fault Tree Analysis Including Component Dependencies.

A Petri net model-based resilience analysis of nuclear power plants under the threat of natural hazards (2022)
Journal Article

Due to global climate change, nuclear power plants are increasingly exposed to the threats of extreme natural disasters. In this paper, a resilience engineering approach is applied to tackle all aspects of nuclear safety, spanning from design, operat... Read More about A Petri net model-based resilience analysis of nuclear power plants under the threat of natural hazards.

Dynamic and dependent tree theory (D2T2): A framework for the analysis of fault trees with dependent basic events (2022)
Journal Article

Fault tree analysis remains the most commonly employed method, particularly in the safety critical industries, to predict the probability or frequency of system failures. Whilst it has its origins back in the 1960s, the assumptions employed in the ma... Read More about Dynamic and dependent tree theory (D2T2): A framework for the analysis of fault trees with dependent basic events.

Optimisation of nuclear reactor primary coolant design and maintenance parameters (2022)
Journal Article

An optimisation methodology is presented using the primary coolant circulation system of a nuclear reactor as its case study, the purpose of which is to find combinations of selected design and maintenance parameters to maximise the reactor safety an... Read More about Optimisation of nuclear reactor primary coolant design and maintenance parameters.

An integrated modelling framework for complex systems safety analysis (2022)
Journal Article

The ever-increasing complexity of engineering systems has fuelled the need for novel and efficient computational tools able to enhance the accuracy of current modelling strategies for industrial systems. Indeed, traditional Fault and Event Tree techn... Read More about An integrated modelling framework for complex systems safety analysis.

A Petri net asset management framework for railway switches and crossings (2022)
Journal Article

Switches and Crossings (S&C) are a fundamental part of any railway network, they allow trains to switch between tracks and to cross over other tracks. They consist of various electrical and mechanical components to which there is a substantial mainte... Read More about A Petri net asset management framework for railway switches and crossings.

A reliability study of railway switch and crossing components (2022)
Journal Article

Within any railway network Switches and Crossings (S&C) are essential. They allow trains to change tracks, allowing different routes to be selected. Despite their necessity, they generally have a lower reliability than plain line track and are often... Read More about A reliability study of railway switch and crossing components.

Reduction of Petri net maintenance modeling complexity via Approximate Bayesian Computation (2022)
Journal Article

The accurate modeling of engineering systems and processes using Petri nets often results in complex graph representations that are computationally intensive, limiting the potential of this modeling tool in real life applications. This paper presents... Read More about Reduction of Petri net maintenance modeling complexity via Approximate Bayesian Computation.

Railway track availability modelling with opportunistic maintenance practice (2021)
Journal Article

The geometry of railway track must be maintained within certain standards in order to provide a highly available network, as well as good ride comfort and safety for all rail users. Modelling is well utilised as part of asset management tools in expl... Read More about Railway track availability modelling with opportunistic maintenance practice.

Incorporating defect specific condition indicators in a bridge life cycle analysis (2021)
Journal Article

Bridges are critical assets for the safe, reliable and functional operation of transportation networks. Infrastructure asset managers are responsible for ensuring that these bridges adhere to rigorous safety standards using the finite resources avail... Read More about Incorporating defect specific condition indicators in a bridge life cycle analysis.

A mathematical programming model to select maintenance strategies in railway networks (2021)
Journal Article

This paper presents a nonlinear integer programming model to support the selection of maintenance strategies to implement on different segments of a railway network. Strategies are selected which collectively minimise the impact of sections’ conditio... Read More about A mathematical programming model to select maintenance strategies in railway networks.

Modelling cycle for simulation digital twins (2021)
Journal Article

Digital twins (DT) form part of the Industry 4.0 revolution within manufacturing and related industries. A DT is a digital model (DM) of a real system that features continuous and automated synchronisation and feedback of optimisations between the re... Read More about Modelling cycle for simulation digital twins.

An alternative approach to railway asset management value analysis: application to a UK railway corridor (2021)
Journal Article

Railway networks are complex systems and the management of such systems is a challenging task for railway asset managers. It is their responsibility to ensure that the network delivers the highest level of performance for all stakeholders, whilst adh... Read More about An alternative approach to railway asset management value analysis: application to a UK railway corridor.

An alternative approach to railway asset management value analysis: framework development (2021)
Journal Article

The management of a diverse asset portfolio is a demanding task for railway asset managers. They must ensure that the network delivers a high level of performance for customers and adheres to safety limits. Reliability, availability, maintainability... Read More about An alternative approach to railway asset management value analysis: framework development.

Dynamic Reliability Assessment of PEM Fuel Cell Systems (2021)
Journal Article

In this paper, a novel model for the dynamic reliability analysis of a polymer electrolyte membrane fuel cell system is developed to account for multi-state dynamics and ageing. The modelling approach involves the combination of physical and stochast... Read More about Dynamic Reliability Assessment of PEM Fuel Cell Systems.

Modelling stochastic behaviour in simulation digital twins through neural nets (2021)
Journal Article

Discrete event simulation (DES) is a widely used technique for modelling systems where state changes occur at discrete points in time. Stochastic behaviour is represented through random variables associated with probability distributions, from which... Read More about Modelling stochastic behaviour in simulation digital twins through neural nets.

The impact of summer heatwaves on railway track geometry maintenance (2021)
Journal Article

Elevated summer temperatures are a disrupting factor on the rail network. Due to the risk of a track buckling under thermal expansion forces, geometry maintenance must be delayed during heatwaves, leading to an overall decreased network availability... Read More about The impact of summer heatwaves on railway track geometry maintenance.

A Bayesian Belief Network method for bridge deterioration detection (2020)
Journal Article

Bridges are one of the most important assets of transportation networks. A closure of a bridge can increase the vulnerability of the geographic area served by such networks, as it reduces the number of available routes. Condition monitoring and deter... Read More about A Bayesian Belief Network method for bridge deterioration detection.

A Petri net approach to assess the effects of railway maintenance on track availability (2020)
Journal Article

The railway infrastructure includes a portfolio of assets that are subjected to degradation and failure processes due to both usage and ageing. As a consequence of degradation and failures, speed restrictions and line closures may be imposed to contr... Read More about A Petri net approach to assess the effects of railway maintenance on track availability.