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Hidden Intentions Behind Recommender Systems: Understanding Online Manipulation as Covert Influence

Master thesis (2024) - J. Mondragón Briseño, M.B.O.T. Klenk, C.N. van der Wal

Recommender System Agent Based Model Manipulation

The emergence of social media and recommendation systems has profoundly transformed user interactions with digital content, bringing in both opportunities and ethical challenges. This thesis scrutinizes the online manipulation exerted by RS, which, while enhancing engagement and ...

The emergence of social media and recommendation systems has profoundly transformed user interactions with digital content, bringing in both opportunities and ethical challenges. This thesis scrutinizes the online manipulation exerted by RS, which, while enhancing engagement and profitability, can guide user behavior subtly and without their awareness. This definition is based on covert influence, a particular account of manipulation.

A critical examination of existing literature reveals a significant gap: while the conceptual framework for online manipulation is well-discussed, empirical studies providing concrete evidence are scant. This research addresses this deficiency by employing an agent-based model to simulate interactions between users and recommendation systems, aiming to systematically analyze and quantify the effects of covert manipulation on user preferences.

This study contributes to the field by operationalizing the concept of manipulation within a controlled simulation of a book recommendation system, providing a clearer understanding of its mechanisms and effects. This approach not only offers insights into the ethical implications of RS but also aligns with current legislative movements, such as the European Union's Artificial Intelligence Act, aimed at regulating and mitigating harmful manipulative practices by intelligent systems. The findings are intended to guide the design and regulation of RS to ensure they serve the user's interests without compromising ethical standards.

The results show that book recommendation systems can modify user preferences by 9.79\% when prioritizing items covertly, while awareness of the intentions and social influence can diminish the effect of the manipulative algorithm's intention to 4.01\% and 3.64\%. When compared to the 2.58\% change in the case of a non-prioritized RS, the values provide a measurable estimation of the difference between manipulative and non-manipulative book RS for the change of user preferences after interacting with it for some time.

Explaining Link Prediction in Graph Neural Networks

Master thesis (2024) - Y. Fu, E. Isufi, M. Khosla, Kubilay Atasu

Explainability Link Prediction Graph Neural Networks (GNN)

Graph Neural Networks (GNNs) have achieved state-of-the-art performance in various applications due to their ability to capture complex structural relationships within graph data. However, their inherent black-box nature poses significant challenges to model interpretability, par ...

A Priori Uncertainty Quantification In Reynolds-averaged Turbulence Models With Bayesian Deep Learning

Master thesis (2024) - L. Jiang, R.P. Dwight

This thesis explores the use of Bayesian Deep Learning to improve uncertainty quantification in Reynolds-Averaged Navier-Stokes (RANS) turbulence models. While RANS models are commonly used in computational fluid dynamics due to their efficiency, they are often criticized for ina ...

Thermally Evaporated MoOx and TaTm as Hole Transport Layers for Perovskite Solar Cells

Towards fully thermally evaporated perovskite solar cells

Master thesis (2024) - J.D. Apawti, L. Mazzarella, J. Yan, P.A. Procel Moya, O. Isabella, F.C. Grozema

Perovskite solar cells Thermal evaporation MoOx Hole transport layer TaTm

As global temperatures rise and energy demands increase, the need for clean, renewable
energy sources is more critical than ever. Solar energy is one of the key solutions, with the
majority of solar panels currently on the market being made from crystalline silicon. Howev ...

As global temperatures rise and energy demands increase, the need for clean, renewable
energy sources is more critical than ever. Solar energy is one of the key solutions, with the
majority of solar panels currently on the market being made from crystalline silicon. However, emerging photovoltaic (PV) technologies such as perovskite solar cells have already demonstrated efficiencies comparable to those of silicon solar cells, making them a promising contender to achieve even higher efficiencies.

Most of the layers in perovskite solar cells are deposited via spincoating, which is a fast and easy process but can only be done on laboratory-scale. However, deposition through thermal evaporation offers significant advantages, enabling fabrication of nanometer-thin films and facilitating large-scale fabrication needed for future industrialization of perovskite solar cell. Therefore, this research aims to develop perovskite solar cells entirely through thermal evaporation.

The reported number of hole transport materials deposited through thermal evaporation is limited. Recently, fully thermally evaporated perovskite solar cells have been created using the hole transport materials MoOx and TaTm, and these hole transport materials will be studies in this thesis.

The MoOx and TaTm were used as single and double hole transport layer to replace the
reference layer of spincoated PTAA. It was found that the MoOx in direct contact with the pervovskite resulted in a chemical reaction, which negatively affected the energy alignment. The MoOx also showed poor charge carrier selectivity, resulting in high interfacial recombination. Great hole extraction from the perovskite was observed for TaTm, however, a misalignment of the band energy with the electrode hindered the hole collection. Improved hole transfer was found with MoOx and TaTm being used a double hole transport layer. Here, the TaTm functions as a passivation layer between the MoOx and perovskite, while effectively blocking the electrons. In turn, the MoOx improved the energy alignment from the TaTm to the electrode to improve the hole collection.

A thickness optimization of the hole transport layers was also performed. For MoOx as
single hole transport layer, it was found that number of oxygen vacancies decreased with
thickness, leading to less recombination. No change was observed for TaTm as single hole
transport layer when varying the thickness. However, as a double hole transport layer with MoOx, increasing the thickness of TaTm led to an increase in Voc . Ultimately, a thin layer of 2 nm MoOx with a 5-nm thick TaTm showed the most promising results, demonstrating a final efficiency of 4.73%.

Time, Activities, and Energy at Berth

A quantitative study of seagoing vessels in the Port of Rotterdam

Master thesis (2024) - G. Meani, J.A. Annema, A. Correljé, Jorrit Harmsen

Port of Rotterdam Berthing Emission Calculation Maritime Operations

Dutch ports face significant environmental challenges due to high greenhouse gas and air pollutant emissions from berthed ships engaged in essential operations. Entities like the Port of Rotterdam and research institutes produced emission inventories to gain insight into ports' e ...

Dutch ports face significant environmental challenges due to high greenhouse gas and air pollutant emissions from berthed ships engaged in essential operations. Entities like the Port of Rotterdam and research institutes produced emission inventories to gain insight into ports' environmental impact.

However, existing emission inventories rely on fixed factors and overlook berthing duration and activities: they assume the same emission factors regardless of the operations performed by vessels. Thus hindering effective emission reduction strategies and infrastructure development.

Consequently, the following research studies areas of improvement for the current emission calculation methods by including berthing time patterns. Then, it will apply this information to the Port of Rotterdam to test the new methodology.

The principal result that emerged from this work is that reality is far more complex than the most widely used models to represent it; luckily, the available data can still grasp this complexity. First, not all berthing events are equal, and the rarest ones still hold a considerable impact on the total berthing time. Additionally, the differences do not exist only as a matter of frequency and duration but also imply different energy requirements, as suggested by the interviewed parties. Consequently, a model based on a standard stop only reliably captures part of the behaviour of moored ships. Second, there is no universal relationship between standard industry size classes and time spent in port. Some ship types show a positive linear behaviour (the larger the ship, the longer the visit berthing time), while others show more complex relationships. Moreover, some fleet types belong to only a few classes; therefore, no size-related difference can be observed in the behaviour of berthed vessels. These considerations apply to metrics of volume (GT), maximum transportable weight (DWT), and also cargo capacity (TEU). Consequently, the size classes commonly used in the industry - which reflect the physical limits of channels, ports, and other waterways - might be insufficient to portray the in-port behaviour of all the fleet types. Third, most ships berth at a single location during a port visit, proving that the duration of a port visit could be the only way to identify different types of berthing events. Finally, even the interviews suggested that the system is much more complex than captured by the currently used models. The division by fleet type might be an oversimplification as the product transported and the ship type considerably influence the behaviour in port and energy consumption.

These results contrast with the emission calculation methodologies commonly used in literature and policy documents, indicating a widespread risk of policy and investment failure because partial data and oversimplified models of reality might have driven policy and economic decisions. Thus, institutions may have enacted regulations with potentially inefficient economic, environmental, and social returns. Consequently, improving the system's knowledge is essential for informed decision-making and risk minimization. This research has shown that this objective is not only reachable but could be achievable without exponentially increasing the required data.

A Fully Compliant Pendulum Balancer with a Spherical Range of Motion

Master thesis (2024) - R.L.B. Barendse, G. Radaelli, J.L. Herder, Mohammad J. Mirzaali

Compliant mechanism Pendulum balancer Compliant spherical joint Optimized stiffness Remote center of rotation

This paper introduces a fully compliant spherical joint with an optimized stiffness profile specifically for balancing a pendulum. The design builds on previous work that has successfully created a fully compliant spherical joint using tetrahedron-shaped elements connected in ser ...

The Influence of Intersection Strategies of Autonomous Terminal Tractor-Only Intersections on the Productivity of an RTG-based Container Terminal

A Simulation Case Study at Portwise

Master thesis (2024) - T.A. Nooyens, M.B. Duinkerken, A.J. van Binsbergen, R.R. Negenborn, Gijsbert Bast

Autonomous Vehicles Simulation Model Discrete Event Simulation Container terminal Autonomous Terminal Tractor Autonomous Terminal Truck Intersection management strategy

Autonomous terminal tractors (ATTs) are a current development as a driver-less alternative to terminal tractors (TTs). This paper focuses on the integration of these ATTs in a rubbertired gantry (RTG)-based container terminal, and more specifically looking at how strategies for A ...

Evaluating surgeon experience to improve AR in liver surgery

Master thesis (2024) - M.L. Pruijt, K.A. Olthof, Matteo Fusaglia, J.S.D. (Sven) Mieog, K. (Koert) Kuhlmann, Theo Van Walsum

Augmented Reality Laparoscopic Intraoperative Liver surgery Image guided surgery

Introduction - Accurate intrahepatic anatomical localization remains challenging for laparoscopic liver resection (LLR) of patients with colorectal liver metastases (CRLMs). Image-guided surgery (IGS) systems utilizing augmented reality (AR) visualizations have been developed to ...

Introduction - Accurate intrahepatic anatomical localization remains challenging for laparoscopic liver resection (LLR) of patients with colorectal liver metastases (CRLMs). Image-guided surgery (IGS) systems utilizing augmented reality (AR) visualizations have been developed to assist in these procedures by projecting virtual models onto the laparoscopic view. However, AR visualization, often presented as a comprehensive model, requires improvements to achieve an effective and positive experience for surgeons. A user study was performed to develop and evaluate multiple AR and VR visualizations and identify the most promising and effective visualizations based on feedback from surgeons. Additionally, adapters with EM sensors are required to track the 30° laparoscopes and enable AR. The secondary objective was to develop and calibrate these adapters.

Methods - Multiple visualizations, categorized into three classes, were developed and assessed on a phantom and patients. The user study consisted of two phases. Phase 1 focused on the development and evaluation of these visualizations. Feedback from three surgeons was gathered using a custom-made survey that assessed experience, effectiveness, and usability. Phase 2 involved evaluating clinical usage of the visualizations and their applications by showing videos of these tests to seven surgeons from two hospitals.

Results - In Phase 1, five patients were included for AR-guided laparoscopic resection. Improvements were made compared to the gold standard whole liver model in AR experience, effectiveness, depth perception, and information balance. In Phase 2, the most promising visualizations from class 1 were the depth shader and target
structures visualization, both preferred by six surgeons. Additionally, all seven surgeons wanted the ability to augment a predefined virtual resection plan. For class 2, all seven surgeons found the US view promising and only one surgeon indicated they would use the virtual painter. Five surgeons indicated they would use the third-person and target view of class 3 during liver procedures. Furthermore, adapters with EM sensors were developed and calibrated to track the 30° laparoscopes and enable AR.

Conclusion - AR is promising in liver surgery when surgeons can easily interpret the visualization and have a positive experience. To be effective, AR systems should accurately localize and define vessels and tumor margins, provide clear depth perception, and offer well-balanced information. Several aspects of AR visualization for the entire liver model have been improved. Future research should further improve these visualization aspects, implement non-rigid registration techniques and on-demand patient-specific activation of structures. These advancements can enable AR integration into the surgical workflow, enhancing precision and effectiveness.

Definition of the Criteria to Evaluate the Viability of Post-Use Options for Excavated Concrete Sewer Pipes in Rotterdam

Master thesis (2024) - A. KERANIS, Q.A.M. Reijtenbagh, D.F.J. Schraven, Dr. ir. Johan Ninan

Circulair economy Circular Construction Industry Sewer pipes Post-use Municipality of Rotterdam

This study aimed to define and evaluate the viability of post-use options for excavated concrete sewer pipes. The research was conducted with a combination of literature review and expert interviews with professionals from the Municipality of Rotterdam. The process involved sev ...

This study aimed to define and evaluate the viability of post-use options for excavated concrete sewer pipes. The research was conducted with a combination of literature review and expert interviews with professionals from the Municipality of Rotterdam. The process involved several key steps. The goal was to create a conceptual framework that can evaluate the viability of post-use options for excavated concrete sewer pipes. Initially, the study identified two existing circular economy theories from which four circular strategies were adopted. The potential post-use options for the excavated sewer pipes, were developed based on those strategies such as reuse, repurpose, refurbish, and recycle. The potential post-use options were identified through literature review. Following this, viability criteria were developed from academic literature and expert interviews. These criteria were categorized into general criteria, which must be met by all post-use options, and specific criteria specified to each circular strategy.A conceptual framework was established using the identified viability criteria, designed to evaluate the practical feasibility of post-use options for concrete sewer pipes. This framework was then applied to a test case involving excavated concrete sewer pipes in Rotterdam, serving as a prototype application to test its practical applicability. Seven potential post-use options were evaluated using the framework. From those seven, only two options were considered viable for the test case of Rotterdam. These were, repurposing the pipes for breakwater construction and recycling them using a conservative breaking installation. Other options were rejected due to factors such as insufficient remaining lifetime, lack of structural integrity, and inefficiency. The study concluded by demonstrating the practical application of leading criteria to evaluate post-use options. It also provided insights into the limitations of the study and suggested areas for future research, particularly in improving data accuracy and expanding the applicability of the criteria. However, the study faced some limitations. Some academic criteria were too generalized and not directly applicable to the specific context of concrete sewer pipes. The study heavily relied on expert opinions from the Municipality of Rotterdam, which may introduce bias or limit the perspective to that specific locality

Dual-Task Training with Consigo

Motivating older adults to follow cognitive and physical training for an active and healthy ageing

Master thesis (2024) - V. Guadagno, J.J. Kraal, C. Schneegass, Tilman Dingler, Ana Isabel Martins

Physical Activity Older adults Cognitive Training

With the European population rapidly aging, addressing the vulnerabilities associated with physical and cognitive decline is essential. Promoting an active lifestyle among older individuals has proven effective in preserving health and independence. Growing evidence suggests that ...

With the European population rapidly aging, addressing the vulnerabilities associated with physical and cognitive decline is essential. Promoting an active lifestyle among older individuals has proven effective in preserving health and independence. Growing evidence suggests that combining cognitive and physical exercises can significantly enhance both cognitive function and physical health, especially among sedentary elderly populations who are at increased risk due to physical inactivity.

This thesis, conducted in collaboration with the Portuguese company Neuroinova, presents the development and evaluation of a digital intervention aimed at integrating physical exercises into their platform for cognitive training COGWEB in individuals experiencing cognitive decline or impairments. The integration process started with ACTIVAS, a program developed in collaboration with researchers from the University of Aveiro, who provided guidelines for an effective physical exercise regimen based on personalization and progression. However, motivating users to adhere to the program, particularly in a remote setting, remained a challenge.

Understanding the needs and barriers of both patients and professionals was crucial to shaping a program that positively impacts user motivation.
Utilizing a user-centered design approach, including generative sessions, interviews with healthcare professionals, and literature reviews, two primary user groups were identified: sedentary individuals with minimal physical activity and busy active individuals with irregular physical exercise patterns. Despite individual differences, the insights revealed that successful integration of physical exercises into COGWEB requires clear, structured guidance from a trusted professional, such as a physiotherapist, alongside engaging and enjoyable exercise activities. Personalization of the program emerged as a key factor in addressing these needs.

The design process focused on ensuring effective guidance and engagement by iteratively testing various prototypes of exercise sessions, with special attention to interaction qualities such as being engaged, guided, proud, trusting, and in control.
The final concept involved a session where cognitive tasks in the form of games—similar to the original COGWEB format—were paired with physical movements and exercises, allowing users to train both cognitive functions and their body simultaneously. Emphasis was placed on providing clear instructions and professional guidance through the presence of a physiotherapist.

Final test results showed promise in motivating sedentary individuals to participate in these sessions, achieving the design goal of ensuring guidance and engagement. While the design objective of this thesis was met within the study's scope, further work is necessary to implement and evaluate the program's long-term effectiveness in real-world settings. The findings suggest that this approach has the potential to significantly increase physical activity levels and improve adherence among elderly COGWEB users, contributing to their overall well-being.

Robust Helicopter Control using Structured H∞-based Multi-Objective Design

Application to Hingeless Rotorcraft

Master thesis (2024) - T. Capra, S.T. Theodoulis, M.D. Pavel

Robust Control Helicopter H-infinity control

This thesis introduces a multi-objective design approach for an Attitude Command-Attitude
Hold (ACAH) and vertical velocity flight control system for the MBB Bo-105 helicopter
longitudinal model. The design employs a decentralized structured 𝐻∞ dynamic controller
usin ...

Threshold Ridge Regression for the Purpose of Turbulence Closure Modelling

Testing sparse regression for the possible creation of transport equations for RANS turbulence modelling

Master thesis (2024) - J.V. Weijers, R.P. Dwight

Regression Turbulence modeling Aerodyanamics Ridge regression PDE FIND

Reynolds averaged Navier Stokes (RANS) models are the industry standard when it comes to computational fluid dynamics (CFD). RANS models have notable shortcomings as the
Reynolds stress is modelled locally and does not include temporal behaviour. Therefore,
current RANS m ...

Directional stability assessment of a wingsail-driven vessel

Master thesis (2024) - G.S. Haenen, A. Coraddu, M. Alexandersson, F. Olsson, A.A.K. Rijkens, P. de Vos, N. Vasilikis

Wingsail Directional stability Wind propulsion Yaw stability Course stability

This thesis investigates the yaw stability of wind-driven vessels using wingsails, addressing the urgent need for decarbonising global shipping. An analytical method is developed to assess directional stability based on aerodynamic and hydrodynamic characteristics, yielding a uni ...

Asteroid Gravity Field Estimation by a Satellite Constellation

Master thesis (2024) - M. Munuera, E. Mooij, J. De Teixeira Da Encarnação, B.C. Root

Kalman Filter Spherical harmonics Asteroid Gravity Field

Asteroid missions stand at the forefront of space exploration endeavours. These face a number of challenges, with safe navigation being one of the main issues. The irregular nature of these bodies creates highly perturbed gravity fields that, if modelled incorrectly, can be a dan ...

Asteroid missions stand at the forefront of space exploration endeavours. These face a number of challenges, with safe navigation being one of the main issues. The irregular nature of these bodies creates highly perturbed gravity fields that, if modelled incorrectly, can be a danger to the safe navigation of the spacecraft. Therefore, improving the gravity field modelling of asteroids is of key importance.

This research aims to improve the gravity field estimation of asteroids through the use of a satellite constellation consisting of a mothership and a set of CubeSats. In particular, it focuses on the modelling and estimation of the gravity field with spherical harmonics (SH), which makes the research only applicable to the navigation of the spacecraft outside of the Brillouin sphere.

The system design is based on a CubeSat constellation orbiting the asteroid that relays measurements back to a mothership that estimates its state and gravity field through an Unscented Kalman Filter (UKF). The research is centered around 433 Eros asteroid for the model implementation, being an irregular body with known characteristics from the Near-Shoemaker mission.

An end-to-end simulation environment is implemented for the system research. This allows for simulating the orbits of the satellites in a real-world environment considering SH gravity field up to degree and order 15, the perturbation effect of the Sun point mass, and the solar radiation pressure. Additionally, it includes a realistic polyhedral shape of the asteroid including its landmarks. The asteroid model is used together with the modelling of the satellite sensors to estimate the measurements that can be obtained in a realistic scenario including sensor errors, visibility, and communications constraints. Furthermore, the simulation environment contains a UKF filter capable of conducting the gravity-field estimates from the measured states of the constellation satellites.

The research conducts a thorough sensitivity analysis of the scenario evaluating how the constellation design impacts the estimates obtained. This analysis evaluates a number of filter designs, and determines that better performance is achieved when the design models the dynamics of several satellites at the same time. This is followed by an analysis of variance, conducted to obtain a better understanding of the constellation characteristics' effects on the filter estimates.

From the results obtained, a design synthesis is conducted to test the system implemented with an optimised constellation design. Furthermore, the filter design is re-evaluated and improved through the addition of better covariance matrix tuning and the addition of a degree-by-degree estimation procedure that allows to reduce computational load, a main constraint of the system. The results obtained show that the model is capable of accurately estimating the gravity field spherical harmonic coefficients with an error lower than 15% when the filter is tuned properly for SH up to degree and order nine. Additional verification of its applicability has been conducted by testing the system with extreme case asteroids, which show that the system requires a thruster and control system for the satellites to be capable of maintaining stable orbits around the asteroids when these have extremely irregular gravity fields.

Absurdist chatbots

A Pataphysical Exploration of Trustworthy AI

Master thesis (2024) - R.A. Postma, R. Bendor, Kars Alfrink

Artificial Intelligence Human Computer Interaction Research Through Design Critical Design Generative AI Trustworthy AI Absurdism Pataphysical Design Solutionism

In an era dominated by technological solutionism, artificial intelligence (AI) is often seen as a quick fix for complex problems. Inspired by the surrealist notion of pataphysics, this graduation project employs a novel, critical design approach to address the imaginary problem o ...

Massively Parallel Analog Front-End Array for Flexible CMOS-based Brain-Computer Interfaces

Master thesis (2024) - A. Diez Clos, D.G. Muratore, K. Bult, Bert Monna

BCI AFE Neural recording ΜECoG EDO Cancellation Embedded DAC

Brain-computer interfaces (BCIs) have the potential to revolutionize human-computer interaction and offer significant biomedical benefits by enabling applications such as closed-loop neuromodulation, mobility restoration for spinal cord injury patients, and therapies for neurodeg ...

Brain-computer interfaces (BCIs) have the potential to revolutionize human-computer interaction and offer significant biomedical benefits by enabling applications such as closed-loop neuromodulation, mobility restoration for spinal cord injury patients, and therapies for neurodegenerative diseases. To fully leverage BCIs’ capabilities, it is crucial to enhance spatial resolution and robustness by increasing the number of recording channels and expanding brain area coverage. However, current approaches often focus on maximizing the channel count within a single recording analog front-end (AFE), limiting scalability and coverage.

This thesis introduces a novel architecture for a low-power and compact AFE, designed for seamless integration into a massively parallel array of distributed single-channel AFEs dedicated to micro-electrocorticography (μECoG) recording. The proposed AFE features a DC-coupled, chopper-stabilized low-noise boxcar sampler (LNB), followed by a passive switched-capacitor low-pass filter (SC-LPF) and a single-slope (SS) analog-to-digital converter (ADC). The LNB enhances anti-aliasing by introducing notches at multiples of the sampling frequency and effectively reduces chopping ripple. An 8-bit quantization is performed using a continuous time comparator synchronized with a globally distributed ramp across all channels of the array. The SS-ADC achieves a 12-bit resolution at the Nyquist rate (1 kSps) through oversampling at a rate of 16 times (OSR = 16).

Additionally, a novel electrode DC offset (EDO) cancellation loop prevents LNB saturation due to large EDO values, ensuring reliable performance in practical scenarios. Notably, this design eliminates the need for large AC coupling capacitors traditionally used for EDO cancellation, leading to a more compact design and improved scalability for high-density neural recording applications.

The proposed architecture is implemented at the transistor level in 40 nm CMOS technology and extensively validated through simulations. The AFE achieves exceptional area efficiency, with an estimated footprint of only 0.0028 mm² per channel. Moreover, the AFE achieves an input-referred noise (IRN) of 1.69 μV_rms over 0.5-500 Hz and provides an EDO compensation exceeding 100 mVpp. The design exhibits an input impedance of 71.4 MΩ and a common-mode rejection ratio (CMRR) of 80.94 dB. Additionally, the AFE achieves a signal-to-noise ratio (SNR) of 43.3 dB with a 1 mV_pp input signal. These results indicate that the presented AFE architecture, and specifically the novel compensation scheme, represent a promising approach for neural recording applications.

Leveraging Parallel Schwarz Domain Decomposition

Using node level parallelism for the implementation of the parallel Schwarz method

Bachelor thesis (2024) - K.J. Gimbergh, A. Heinlein, B. van den Dries

Numerical analysis High Performance Computing Domain Decomposition

This thesis concerns the implementation of parallel Schwarz domain decomposition using node-level parallelism, focusing on the parallel Schwarz method in comparison with the Jacobi iterative method. The study goes into the complexities of domain decomposition methods for solving ...

Characterising the Post-Collision Tumbling Dynamics and Attitude Control Retrieval of Solar-Sails

Master thesis (2024) - L.A.V. Veithen, M.J. Heiligers, O. Çelik

Solar-sailing is a promising propellant-free propulsion method leveraging the momentum of photons to generate a thrust force, making them attractive for long-term missions both in Earth-bound and interplanetary space. In Earth orbit, solar-sails have been envisioned for space deb ...

Design and Evaluation of a Soft Hydro-Pneumatic Haptic Ring for Multimodal Texture Rendering

Master thesis (2024) - A. Sanz Cozcolluela, Y. Vardar, B.F. Fereidoonnezhad, Dr. S (Sepideh) Ghodrat, J. Jovanova

Wearable Multimodal Haptics Soft actuators Hydraulic Pneumatic Texture rendering

With the growing popularity of virtual and augmented reality, there is an increasing demand for haptic devices that can replicate naturally occurring tactile sensations. Specifically, multimodal devices capable of delivering multiple types of haptic feedback simultaneously are cr ...

Proactive Airline Disruption Management: Increasing Schedule Robustness by Simulating Flexibility Measures

Master thesis (2024) - J.M. Hinsenveld, A. Bombelli

Disruptions in airline operations significantly decrease passenger satisfaction, and have a large influence on the profits of airlines, accounting for an estimated cost of 5 to 10% of yearly revenue. At the same time, disruptions are inevitable and difficult to predict, so should ...

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