AI-Assisted Design & Optimization for Predictive Maintenance: A Case Study using Deep Learning and Search Metaheuristics for Structural Health Monitoring in Aviation

One of the classical solutions to maintain the aircraft structural integrity is to rely on the analysis of non-destructive testing (NDT) inspector with various inspection methods. However, it is relatively expensive in matter of time and costs to train human resources until the certification is reached. Further, in majority of the cases of...

Shearography non-destructive testing and defect characterisation of thick composite structures

THICK composite materials, e.g., thickness of more than 50 mm, are increasingly being used across diverse industry sectors owing to their significant advantages of weightsavings, superiormaterial properties and load-carrying capability. These materials tend to be adopted in safety-critical applications such as large primary or secondary load...

Influence and Detection of Vacuum Bag Leakages in Composites Manufacturing

Composites are increasingly used in the aerospace industry due to their lightweight potential and flexible design options. The most widespread manufacturing process for large components made of fibre composites is still the open mould process. In this process, a composite component is placed on a mould and hermetically sealed with a vacuum bag...

Decisions on life-cycle reliability of flood defence systems

Many countries rely on flood defence systems to prevent economic damage and loss-of-life due to catastrophic floods. Asset managers of flood defence systems need to cope with the consequences of structural degradation, and changing societal and environmental conditions, in order to satisfy performance requirements and optimize societal value of...

Automated Defect Analysis using Optical Sensing and Explainable Artificial Intelligence for Fibre Layup Processes in Composite Manufacturing

In modern aircraft, structural lightweight composite components are increasingly<br/>used. To manufacture these components in a costeffective way, robust production systems for the manufacturing of complex fibre composite components are necessary. A rather novel but already established process for fibre material deposition is the Automated Fibre...

Inverse Electromagnetics for EUV mask metrology and inspection

The importance of inverse problems is paramount in science and physics because their solution provides information about parameters that cannot be directly observed. This thesis discusses and details the application of a few inverse methods in optical imaging, metrology and inspection of lithographic targets, particularly patterned structures on...

Sensor-based quality inspection of secondary resources: Laser-induced breakdown spectroscopy

The quality control of materials from waste is an important step for acceptance in new high-quality products. Given the large volumes and complexity of waste streams, this requires advanced sensor technology such as the Laser Induced Breakdown Spectroscopy (LIBS) investigated in this thesis. Recyclers often rely solely on manual sorting and...

Use of volunteers' information to support proactive inspection of hydraulic structures

This thesis describes the development and testing of a methodology to use information collected by volunteers and technicians on the status of hydraulic structures, applicable for day-to-day risk management. The study was performed in the northeastern Italian Alps of the Friuli Venezia Giulia region. A decision support method was developed and...

Cybersecurity via Intermediaries: Analyzing Security Measurements to Understand Intermediary Incentives and Inform Public Policy

Research in the field of information security economics has clarified how attacker and defender incentives affect cybersecurity. It has also highlighted the role of intermediaries in strengthening cybersecurity. Intermediaries are organizations and firms that provide the Internet’s infrastructure and platforms. This dissertation looks at how...

Assessment Methods for Structural and Hydraulic Properties of Concrete Sewer Pipes

Asset management is a tool for maintaining the required level of serviceability of urban drainage systems, which are costly to construct and in some cases even more costly to replace. The required asset management effort to achieve a certain level of service is unclear due to a limited knowledge on sewer failure mechanisms and due to scarcity of...

Detection of early squats by axle box acceleration

This thesis discusses a new method for detection of short track irregularities, particularly squats, with axle box acceleration (ABA) measurements. A squat is a surface initiated short track defect, associated with high frequency vibrations of the wheel-rail system. High stresses in the contact patch at squats cause accumulation of plastic...

Focusing Automatic Code Inspections

Automatic Code Inspection tools help developers in early detection of defects in software. A well-known drawback of many automatic inspection approaches is that they yield too many warnings and require a clearer focus. In this thesis, we provide such focus by proposing two methods to prioritize inspection results, based on the execution...

Designs and algorithms for packet and content inspection

This dissertation deals with essential issues pertaining to high performance processing for network security and deep packet inspection. The proposed solutions keep pace with the increasing number and complexity of known attack descriptions providing multi-Gbps processing rates. We advocate the use of reconfigurable hardware to provide...

Renovation techniques for fatigue cracked orthotropic steel bridge decks

This dissertation presents the research into renovation techniques for orthotropic steel bridge decks. These techniques are needed to solve fatigue problems in the decks of these bridges, as several fatigue cracks have been detected in the deck structure of these bridges the last decade. A well-known example of fatigue cracks are those observed...

Foundations of Acoustic Methods Used in Non-Destructive Inspection of Laminated Materials

Ultrasonic inspection has become one of the most popular nondestructive testing technique because of its versatility and easy operation. It can detect internal cracks and inclusion type defects in homogeneous or layered materials, often without much difficulty. Layered materials, which are also called laminated materials, have become widely used...

Ultrasonic imaging for the characterization of defects in steel components