NUI Maynooth Eprint Archive
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An 18‐month follow‐up of the Covid‐19 psychology research consortium study panel: Survey design and fieldwork procedures for Wave 6
No full textObjectives: Established in March 2020, the C19PRC Study monitors the psychological and socio-economic impact of the pandemic in the UK and other countries. This paper describes the protocol for Wave 6 (August-September 2021).
Methods: The survey assessed: COVID-19 related experiences; experiences of common mental health disorders; psychological characteristics; and social and political attitudes. Adult participants from any previous wave (N = 3170) were re-invited, and sample replenishment procedures helped manage attrition. Weights were calculated using a survey raking algorithm to ensure the on-going original panel (from baseline) was nationally representative in terms of gender, age, and household income, amongst other factors.
Results: 1643 adults were re-interviewed at Wave 6 (51.8% retention rate). Non-participation was higher younger adults, those born outside UK, and adults living in cities. Of the adults recruited at baseline, 54.3% (N = 1100) participated in Wave 6. New respondent (N = 415) entered the panel at this wave, resulting in cross-sectional sample for Wave 6 of 2058 adults. The raking procedure re-balanced the longitudinal panel to within 1.3% of population estimates for selected socio-demographic characteristics.
Conclusions: This paper outlines the growing strength of the publicly available C19PRC Study data for COVID-19-related interdisciplinary research
You Are Gone From Me. This publiction is by Padraig Cunningham and part of Decade of Centenaries Artist Commission 2023, ‘Douglas Hyde (1860-1949) – Cultural Influencer’.
No full textThis publication, You Are Gone From Me, highlights Hyde’s dedication to collecting folklore from Irish-speaking members of the community, such as Biddy Crummy. As the first to recognise the cultural importance of these individuals, Hyde preserved their songs, poetry, and folklore, ensuring that their voices and traditions were not lost to history. This publication celebrates Hyde’s enduring cultural legacy
Wave energy converter array layout control co-design for different mooring configurations
No full textThis paper introduces a comprehensive control co-design (CCD) methodology for optimising the
layout of wave energy converter (WEC) arrays from an
economic perspective. The CCD approach ensures that all
optimised WEC and array parameters are aligned with
the final control strategy, resulting in an optimal design
from an overall perspective. By integrating a spectral-based
control strategy into the array layout design, this study aims
to achieve an optimal WEC array layout that maximises
energy absorption while considering the economic cost of
the system. The proposed methodology provides a unique
design approach that combines optimal layout design with
optimal control performance. The analysis focuses on a
three-device in-line WEC array, with different spacing and
mooring arrangements. Energy capture and system cost
evaluation are calculated, and the results obtained using
the spectral-based controller are compared with those obtained using a benchmark passive controller. The findings
underscore the importance of integrating advanced control
strategies at the design stage to enhance energy absorption
and cost reduction
The politics of algorithmic rank systems in the Brazilian erotic webcam industry
No full textThis article examines the structuring of algorithmic rank systems in
the Brazilian webcam industry. The article questions the criteria
behind those automated systems and their impacts on the
working conditions of performers. The research comprises a four-year digital ethnography (from 2016 to 2020) of Brazil’s two
major webcamming platforms, Camera Hot and Camera Prive.
Fifteen in-depth interviews were conducted with cisgender
women performers. The results reveal that rankings rely on axes
of difference, centrally gender, race and age, foregrounding
young white cisgender women. The unequal distribution of
visibility affects the work conditions of the performers who do
not fit platforms’ patterns, pressing them to negotiate with
ranking criteria to succeed on camming. As the Brazilian
camming business promotes the homogenization of services and
prices, ranking stratifications hamper performers’ opportunities to
engage and thrive on platforms. The research argues that
inequalities imposed by rankings are already seen in the Brazilian
sex trades
A Dominant Interferer Plus Mean Field-Based Approximation for SINR Meta Distribution in Wireless Networks
No full textThis paper proposes a novel approach for computing the meta distribution of the signal-to-interference-plus-noise ratio (SINR) for the downlink transmission in a wireless network with Rayleigh fading. The novel approach relies on an approximation mix of exact and mean-field analysis of interference (dominant interferer-based approximation) to reduce the complexity of analysis and enhance tractability. In particular, the proposed approximation omits the need to compute the first or the second moment of the SINR that is used in the beta approximation typically adopted in the literature but requires of computing the joint distance distributions. We first derive the proposed approximation based on a Poisson point process (PPP) network with a standard path-loss and Rayleigh fading and then illustrate its accuracy and operability in another four widely used point processes: Poisson bipolar network, Matérn cluster process (MCP), K -tier PPP and Poisson line Cox process (PLCP). Specifically, we obtain the SINR meta distribution for PLCP networks for the first time. Even though the proposed approximation looks simple but it shows good matching in comparison to the popular beta approximation as well as the Monte-Carlo simulations, which opens the door to adopting this approximation in more advanced network architectures
Energy Efficiency Analysis of Charging Pads-Powered UAV-Enabled Wireless Networks
No full textThis paper analyzes the energy efficiency of a novel system model where unmanned aerial vehicles (UAVs) are used to provide coverage for user hotspots (user clusters) and are deployed on charging pads to enhance the flight time. We introduce a new notion of “cluster pairs” to capture the dynamic nature of the users spatial distribution in order to exploit one of the top advantages of UAVs, which is the mobility and relocation flexibility. Using tools from stochastic geometry, we first derive a new distance distribution that is vital for the energy efficiency analysis. Next, we compute the coverage probability under two deployment strategies: (i) one UAV per cluster pair, and (ii) one UAV per cluster. Finally, we compute the energy efficiency for both strategies. Our numerical results reveal which of the two strategies is better for different system parameters. Our work investigates some new aspects of the UAV-enabled communication system such as the dynamic density of users and the advantages or disadvantages of one- or two-UAV deployment strategies per cluster pair. By considering the relationships between the densities of user cluster pairs and the charging pads, it is shown that an optimal cluster pair density exists to maximize the energy efficiency
Comparing the Effect of Different Electrode Subsets on P300 Speller Performance
No full textThe P300 speller is a widely used application in
brain-computer interface research. It has been demonstrated
that the P300 speller can serve as a neurofeedback training
tool for attention enhancement by gradually increasing the
difficulty of the spelling task. This adaptive approach makes
it harder for users to spell words correctly, encouraging them
to improve their attention to counteract the increasing difficulty.
Therefore, the adaptive P300 speller has the potential to serve
as a treatment option for children with ADHD, elderly patients
with dementia, and as a cognitive enhancement tool for healthy
adults. However, the training length, including setup time,
needs to be quick to ensure user acceptability. This study
investigates the effect of different electrode subsets on P300
speller performance, with and without the use of the xDAWN
spatial filter. Results indicate that the xDAWN spatial filter can
improve performance with many electrodes but can decrease
results with fewer than eight electrodes. For scenarios where
near-perfect performance is crucial and many electrodes are
available, a set of 16 electrodes with the xDAWN spatial filter
is recommended. For situations where cost and setup time are
a concern and lower performances are acceptable, using six
electrodes without the spatial filter were found to be sufficient
Wave-to-Wire Control of an Oscillating Water Column Wave Energy System Equipped with a Wells Turbine
No full textWave energy is a significant source of renewable energy which is harnessed by wave energy converters (WECs). However, the high levelised cost of energy
(LCoE) associated with wave energy projects hinders the
commercial development of WECs. To minimise the LCoE,
comprehensive control strategies, to maximise electric energy production, are essential. The oscillating water column
(OWC) is one of the most promising WECs for harnessing
wave power, especially due to its relative simplicity of operation. Due to the overbearing issue of turbine efficiency,
the vast majority of OWC control strategies focus on a
simplified control objective, namely turbine efficiency maximisation. However, it is important to note that rotational
speed control impacts generator performance. Additionally,
for Wells turbines, rotational speed control also affects
the hydrodynamic performance, specifically the wave-to-pneumatic energy conversion process. Therefore, Wells
turbine rotational speed should be ideally modulated to
improve the overall wave-to-wire (W2W) efficiency of the
OWC system, rather than just turbine efficiency. In this
paper, a control strategy for maximising W2W efficiency
of a fixed OWC WEC, equipped with a Wells turbine,
is designed. The proposed control strategy comprises two
parts: Firstly, a ‘global’ setpoint, which considers the entire
OWC W2W model, is derived. Secondly, a Lyapunov-based
nonlinear controller is designed to track the aforementioned setpoint. Results from numerical simulation show
that, in comparison to the somewhat traditional turbine
efficiency maximising control approach, the proposed W2W
control strategy significantly improves W2W efficiency for
the considered sea states
Feature selection and hierarchical modelling in tree-based machine learning models.
No full textTree-based algorithms are quite popular in the machine learning area in general,
due to its many advantages: interpretability, flexibility, high prediction power, and
so on. They can be used to many different classification and regression problems,
and are in constant development. Because of that, there are many tree-based machine
learning algorithms available, including both standard and Bayesian options.
In this thesis, we propose a few methodological extensions to tree-based models
including BART, which is the main Bayesian version of it. The list of methods
is: extending and generalizing the feature gain penalization idea for tree- based
algorithms; extending the BART model into HEBART, to deal with hierarchical
data, when there is a grouping variable present; lastly, extending HEBART to deal
with more complicated hierarchical data situations. The methods proposed here
aim to tackle important deficiencies of the algorithms in question, as they are very
popular and in high-demand at the moment.
The first method develops a new gain penalization idea that exhibits a general
local-global regularization for tree-based models, which is able to create much more
powerful and interpretable generalizations of the gain penalization method. One of
the main advantages of this technique is that it can be applied to all (non-Bayesian)
tree-based algorithms without loss of generality. The second method switches
topics a bit and deals with simple yet powerful extension of Bayesian Additive
Regression Trees which we name Hierarchical Embedded BART (HEBART). This
model allows for random effects to be included at the terminal node level of the set
of regression trees estimated in BART, making it a non-parametric alternative to
mixed effects models. At last, we propose yet a few more extensions to HEBART,
namely, I) the Crossed Random Effects HEBART (CHEBART) which allows for
multiple grouping variables in the same model; II) the Nested Random Effects
HEBART (NHEBART) approach, which accounts for multiple nested grouping
variables, where each group level has sub-levels (or sub-groups)