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norskDoktorgradsavhandlinger (Fakultet for ingeniørvitenskap og teknologi)
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A Decision Support Framework for Metal Additive Manufacturing Adoption in Small and Medium-Sized Enterprises
(Doctoral thesis; Doktorgradsavhandling, 2024-12-03)Today's manufacturing landscape is undergoing constant changes, particularly through the widespread integration of advanced digital technologies. Among these, Metal Additive Manufacturing (MAM) stands out, signaling a new era of flexibility and customization capabilities that promise to significantly enhance business competitiveness, sustainability, and cost efficiency. However, the outcomes of MAM ... -
Sea Spray Icing Prediction: Integrating Experiments, Machine Learning, and Computational Fluid Dynamics
(Doctoral thesis; Doktorgradsavhandling, 2024-05-27)<p>Ice accretion is challenging for maritime and offshore operations in the Polar regions. Activities related to tourism, oil and gas exploration, fishing, and offshore wind energy are increasing in the arctic. Ice accretion on vessels and offshore structures pose a threat to structural integrity, vessel stability, and personnel safety in outdoor working environments. Freezing sea spray is the largest ... -
Enhancing AI Systems through Representative Dataset, Transfer Learning, and Embedded Vision
(Doctoral thesis; Doktorgradsavhandling, 2024-02-28)<p>Artificial intelligence (AI) encompasses a range of techniques that enable machines to perceive, learn, and make intelligent decisions and it has emerged as transformative technology in many applications. This thesis presents the development of an AI model, focusing on the significance of the primary representative dataset and the effectiveness of transfer learning and fine-tuning techniques for ... -
Intelligent self- and reconfigurable manufacturing system
(Doctoral thesis; Doktorgradsavhandling, 2023-12-12)Over the past few years, the market has shifted away from mass production towards mass customization and personalized production. This shift has made it necessary for manufacturing companies to change their manufacturing line more frequently, which can be both expensive and time-consuming. To overcome this challenge, reconfigurable manufacturing systems (RMS) have been proposed as a solution. However, ... -
Voltage Control in Smart Distribution Network with High Integration of DERs
(Doctoral thesis; Doktorgradsavhandling, 2023-12-08)The thesis aims to address research questions of how the high integration of distributed energy resources (DER) influences the voltage profile of the distribution network and how the smart converters in DERs can be utilized to address voltage violations. For this purpose, the thesis investigates the coordinated active and reactive power control in smart converters to mitigate voltage violations. To ... -
Capacitive power transfer for maritime electrical charging applications
(Doctoral thesis; Doktorgradsavhandling, 2023-07-07)Wireless power transfer can provide the convenience of automatic charging while the ships or maritime vehicles are docking, mooring, or in a sailing maneuver. It can address the challenges facing conventional wired charging technologies, including long charging and queuing time, wear and tear of the physical contacts, handling cables and wires, and electric shock hazards. Capacitive power transfer ... -
Acoustical properties of solid-liquid composites and related computational problems
(Doctoral thesis; Doktorgradsavhandling, 2023-07-05)The thesis provides a study of acoustical performance and characterisation of solid-liquid composites. We address both experimental and numerical aspects of fluid-solid interaction problems. In the experimental part, we perform a comparative study of the sound damping properties of perforated plates with viscoelastic inclusions, such as polyurethane and soap emulsified with oil grease lubricant, ... -
Some new Contributions to Neural Networks and Wavelets with Applications
(Doctoral thesis; Doktorgradsavhandling, 2023-03-21)<p>In this Ph.D. thesis, we focus on some problems of general interest both in engineering sciences and applied mathematics. The close connection between some problems concerning neural networks, wavelets, structural health monitoring, and modern Fourier analysis is highlighted and applied in various ways. The main body of the Ph.D. thesis consists of six papers, A–F, which are put into a more ... -
A Decision-Support Framework for Smart and Sustainable Reverse Logistics Network Design
(Doctoral thesis; Doktorgradsavhandling, 2022-10-06)The Fourth Industrial Revolution, namely Industry 4.0, has provided opportunities for digitalization and paradigm shifts in many industries and business sectors. Reverse logistics is currently being increasingly focused on by worldwide companies and governments due to the pressure on sustainable development and circular economy. Through the gradual but steady adoption of several disruptive ... -
Architectures and technologies for increased agility in small-scale manufacturing systems
(Doctoral thesis; Doktorgradsavhandling, 2022-06-16)<p>The rapid booming of industry 4.0 technologies has been boosting further development of industrial manufacturing systems in the recent two decades. An increasing number of disruptive yet enabling technologies are becoming available for industrial applications. However, while the factories becoming more complex, a proliferation of incompatible systems that have been developed by different vendors ... -
Approximation properties of Cesàro means of Vilenkin-Fourier series
(Doctoral thesis; Doktorgradsavhandling, 2022-05-05)<p>This PhD thesis focuses on the investigation of approximation properties of Cesàro means of the Vilenkin-Fourier series. In particular, we obtain some new inequalities related to the rate of <i>L<sup>p</sup></i> approximation by Cesàro means of the Vilenkin-Fourier series of functions from <i>L<sup>p</sup></i>. These inequalities imply sufficient conditions for the convergence of Cesàro means of ... -
Some new mathematical and engineering results connected to structural problems
(Doctoral thesis; Doktorgradsavhandling, 2022-04-08)<p>The research in this PhD thesis is focused on some problems of general interest in both applied mathematics and engineering sciences. It contains new results, which can be directly used for solving some important structural problems in engineering sciences, but which are also of interest in pure mathematics. The main body of this PhD thesis consists of six papers (Papers A – F). <p>In Paper A ... -
A study of bounded operators on martingale Hardy spaces
(Doctoral thesis; Doktorgradsavhandling, 2021-12-13)<p>The classical Fourier Analysis has been developed in an almost unbelievable way from the first fundamental discoveries by Fourier. Especially a number of wonderful results have been proved and new directions of such research has been developed e.g. concerning Wavelets Theory, Gabor Theory, Time-Frequency Analysis, Fast Fourier Transform, Abstract Harmonic Analysis, etc. One important reason for ... -
The Impact of Ambient Temperature on Low Carbon Energy Supply - Modelling and optimization studies on the supply of hydrogen energy from northern Norway
(Doctoral thesis; Doktorgradsavhandling, 2021-12-10)To avoid the worst impacts of climate change a rapid green energy transition is required where traditional fossil fuels are replaced by low-carbon alternatives. One attractive route to emissions reduction is blue hydrogen, which has lower CO<sub>2</sub> emissions that traditional hydrogen production. For hydrocarbon exporters, increased blue hydrocarbon production can be achieved in two main ways: ... -
Study of Atmospheric Ice Accretion on Wind Turbine Blades
(Doctoral thesis; Doktorgradsavhandling, 2021-09-02)<p>This Ph.D. work concerns itself with the atmospheric ice accretion on wind turbine blades. The wind energy has been at the forefront of the renewable energy generation for the last several decades, with the amount and capacity of installed wind turbines steadily increasing. The cold climate (CC) regions around the world like Finland, Germany, Slovak Republic, Norway, Czech Republic, UK, Sweden, ... -
Study of the in-cloud dry ice accretion on cylinders for low values of the Stokes number
(Doctoral thesis; Doktorgradsavhandling, 2021-08-31)The study of the atmospheric ice accretion has received some attention from the scientific community in the past, with the available knowledge spanning from the works of the Langmuir and Blodgett (1946) on the Mt. Washington Observatory till the analytical parameterization of the Finstad et al. (1988), with the latter being the current analytical benchmark and the integral part of the ISO 12494 ... -
Mathematical modelling of bioenergy systems for stability analysis and parametric sensitivity
(Doctoral thesis; Doktorgradsavhandling, 2021-03-19)<p>This thesis presents a research study on bioreactor design and biochemical processes for conversion of biomass into bioenergy and develops mathematical models that can be used for designing better reactors and control systems. Good design of the bioreactors and understanding of the biochemical process is essential to control the process for maximizing the yield. Improving the performance efficiency ... -
An applied investigation of viscosity–density fluid sensors based on torsional resonators
(Doctoral thesis; Doktorgradsavhandling, 2020-12-04)Real-time viscosity and density measurements give insight into the status of many chemical and biochemical processes and allow for automated controls. In many applications, sensors that enable the real-time measurements of fluid properties use resonant elements. Such sensors measure induced changes in the element’s resonance frequency and damping that can be related to the fluid properties. These ... -
Geometric Modeling- and Sensor Technology Applications for Engineering Problems
(Doctoral thesis; Doktorgradsavhandling, 2020-10-20)In applications for technical problems, Geometric modeling and sensor technology are key in both scientific and industrial development. Simulations and visualization techniques are the next step after defining geometry models and data types. This thesis attempts to combine different aspects of geometric modeling and sensor technology as well as to facilitate simulation and visualization. It includes ... -
Representation and application of spline-based finite elements
(Doctoral thesis; Doktorgradsavhandling, 2020-03-31)Isogeometric analysis, as a generalization of the finite element method, employs spline methods to achieve the same representation for both geometric modeling and analysis purpose. Being one of possible tool in application to the isogeometric analysis, blending techniques provide strict locality and smoothness between elements. Motivated by these features, this thesis is devoted to the design and ...
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