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Development of High-Performance Wireless Channel Models for Transportation Systems
No full textOne promising technology in rail signaling is communication-based train control (CBTC), offering substantial enhancements to the efficiency of light rail, subway, and high-speed train networks. In CBTC systems, telecommunications are employed between the train and track equipment for traffic management and infrastructure control. Due to the safety-critical nature of rail signaling and the rapid, cost-effective nature of system deployment, the existence of an accurate and efficient wave propagation model for transportation systems is critical. This thesis presents a high-performance wireless channel model, based on parabolic wave equation (PWE) methods, for radio wave propagation predictions in realistic and complex railway environments. The developed 3-D PWE-based tools are validated in a variety of scenarios, including waveguides, irregular terrain environments, and realistic arched tunnels. Then, a systematic analysis of the numerical error and computational complexity of various PWE methods are provided, and concrete guidelines for the choice of parameters are also given. Furthermore, the thesis also presents an efficient model for propagation prediction in tunnels by combining the PWE method with sparse Fourier transform techniques. Moreover, two machine learning (ML)-driven PWE methods are introduced, aimed at offering promising solutions to reconcile the traditional trade-off between accuracy and efficiency. Finally, a physics-based trajectory design approach for cellular-connected unmanned aerial vehicles (UAVs) in rainy environments, and an efficient localization framework in road tunnels are presented. It is shown that such modeling tools can be quite useful as they enable the design and optimization of wireless communication systems through integrating propagation modeling with network-level systems, instead of carrying out these tasks conventionally
Confidence is predicted by pre- and post-choice decision signal dynamics
No full textIt is well established that one’s confidence in a choice can be influenced by new evidence encountered after commitment has been reached, but the processes through which post-choice evidence is sampled remain unclear. To investigate this, we traced the pre- and post-choice dynamics of electrophysiological signatures of evidence accumulation (Centro-parietal Positivity, CPP) and motor preparation (mu/beta band) to determine their sensitivity to participants’ confidence in their perceptual discriminations. Pre-choice CPP amplitudes scaled with confidence both when confidence was reported simultaneously with choice, and when reported 1 second after the initial direction decision with no intervening evidence. When additional evidence was presented during the post-choice delay period, the CPP exhibited sustained activation after the initial choice, with a more prolonged build-up on trials with lower certainty in the alternative that was finally endorsed, irrespective of whether this entailed a change-of-mind from the initial choice or not. Further investigation established that this pattern was accompanied by later lateralisation of motor preparation signals toward the ultimately chosen response and slower confidence reports when participants indicated low certainty in this response. These observations are consistent with certainty-dependent stopping theories according to which post-choice evidence accumulation ceases when a criterion level of certainty in a choice alternative has been reached, but continues otherwise. Our findings have implications for current models of choice confidence, and predictions they may make about EEG signatures.Science Foundation IrelandWellcome Trust -- Submitted for publication after 1 Jan 2021: 0m embargo and CC-BY licenseEuropean Commission Horizon 202
An international survey of patient radiation dose management practice in interventional radiology
No full textInterventional radiology (IR) is a rapidly evolving imaging domain with potential to deliver high patient radiation doses resulting in stochastic effects of radiation but also tissue reactions. As a result of the potential for high patient doses and in some cases tissue reactions, high standards of radiation safety practice are imperative and much work has been done on the development of patient radiation dose management strategies internationally by organizations, professional societies, countries, and individuals. These strategies can be deployed before, during and after IR procedures through appropriate patient consent, dose monitoring and patient follow-up. This questionnaire-based study surveyed fixed (non-mobile) IR departments across seven countries incorporating a wide range of IR specialties including cardiology, neurology and vascular interventional radiology which collectively completing over 250,000 IR procedures annually. Patient radiation dose management was investigated. Respondents indicated that pre-procedure IR patient consent included all radiation effects in only 35% of cases. The patient skin dose surrogate parameter of Kerma to air at a reference point (Kar) is under-reported by respondents suggesting a lack of familiarity with this dose parameter which is highlighted as surrogate for peak skin dose (PSD). Only 23% of respondents indicated that their facility uses a substantial radiation dose level (SRDL) and only half of those reporting to use SRDLs inform the patient after these dose levels have been reached. Poor compliance with unambiguous, readily available best practice guidance was observed highlighting patient communication, patient dose quantification and subsequent patient dose management concerns
The polarisation constant for JB*-triples
No full textIn [2]. Harris showed that for any J*- alegbra, Z, the polarisation constant c(n, Z) satisfies... A norm estimate for a derivative of the generalised Moebius transformation on JB*-triples is presented in Corollary 3.6 of [4]. This estimate allows us to extend the result of Harris to the case of JB*-triples, whose open unit balls have the same rich holomorphic structure as those of J*algebras. The JB*-triples are, indeed, exactly those Banach spaces whose open unit balls have a transitive group of biholomorphic automorphisms
Demoicratic Political Legitimacy in the European Union: The Eurosystem and the Conduct of Supranational Monetary Policy in Times of Crisis
No full textThis thesis evaluates the Eurosystem’s institutional design and function, particularly under crisis conditions, through the lens of normative legitimacy. It develops an integrated framework of normative standards for European monetary integration, identifying public justification within a diverse community of democratic peoples as the core requirement of legitimacy. Advancing international political theory, this research develops an innovative model of public justification as a transnational social contract among free and equal peoples. Through an adapted Original Position thought experiment tailored to the EMU’s dynamic and asymmetrically interdependent structure, it establishes three core standards of normative legitimacy, including the requirements of stability, joint self-direction and equity. These standards are applied to Eurozone central banking law and practice, critiquing prevailing monetary orthodoxy and analysing how crisis has shaped the Eurosystem since 2008. While the Eurosystem’s original establishment upon a price stability target and its post-crisis functional expansion meet certain legitimacy criteria, applying these standards reveals a need to further develop the secondary mandate, accountability framework, and financial stability architecture within the Eurozone. The thesis thus proposes reforms supporting the establishment of a constrained conservative central banking regime, advocating enhanced political and judicial oversight at both national and European levels, a reinterpretation of the secondary mandate as a convergence objective, a strengthened decentralisation principle for the Eurosystem, a completed banking union, and the creation of a European stability fund. Addressing relatively neglected issues in political theory and applying normative tools often overlooked in empirical studies, this research presents a novel perspective on Eurozone political economy and governance, aiming to foster a more stable and equitable monetary union among Europe’s diverse peoples, directing the process of economic and monetary integration 'together but not as one’
Co-creating diversity and inclusion training resources for delivery to staff and learners on Teagasc further education and training courses
No full textThis project employs Participatory Action Research (PAR) to co-create a diversity and inclusion training resource with staff, and to pilot and evaluate its effectiveness with learners in Teagasc further education and training courses. This initiative aligns with the 2018-2022 Teagasc People Strategy and the 2021-2024 Teagasc Statement of Strategy highlight the importance of diversity and inclusion within Teagasc education. This project builds directly upon two previous MAIS projects on diversity and inclusion in agricultural education which indicate that staff and learners would benefit from bespoke training resources. Diversity and inclusiveness training should help our students to be prepared for the increasingly diverse world when they graduate. It should also help ensure that Teagasc education attracts a student body that is diverse in terms of gender, race, age, ability, and sexual orientation. PAR was the overall methodological approach. The researcher established a staff working group at Ballyhaise Agricultural College and facilitated meetings to identify priority issues and explore options. This process led to the development and delivery of a pilot training initiative, which was a dignity and respect workshop for students. Throughout the process, notes and observations were made, and a reflective journal was kept by the researcher. Students were surveyed following the workshops and the working group staff reflected on workshop effectiveness. The main diversity challenges are accessibility, minority representation, gender bias, and support for students with disabilities. A working group designed and developed a dignity and respect workshop, using case studies to engage students. The group members facilitated the pilot workshops. Post-workshop evaluation and student surveys showed strong student engagement, relevance to real-world scenarios, and valuable insights for staff development. Themes from researchers' reflections included trust-building, facilitation challenges, group dynamics, emotional responses, and the success of interactive methods. Overall, the workshops increased awareness of diversity and inclusion, promoted practical skills, and promoted meaningful staff-student connections, achieving positive outcomes for all participants. This process has the potential to be replicated and adapted in other agricultural colleges and for additional topics, provided it is supported by thorough planning and skilled facilitation
Investigation of Polymer Integrated Smart Piezoelectric Fillers
No full textThis study investigates the influence of fillers on the piezoelectric response and material properties of PVDF and epoxy-based polymer composites, focusing on fracture behaviour, mechanical performance, thermal behaviour, and structural integrity. PVDF films were produced using solvent casting and hot pressing followed by various processing techniques aimed at increasing the β phase content of PVDF. A contact poling unit was designed, and the poling process was optimised. The optimal processing sequence - solvent casting, hot pressing, quenching, and cold rolling - yielded 81% β phase content. PVDF based piezoelectric composites were prepared using this sequence with 0.2 wt.% multiwalled carbon nanotubes (MWCNT), 20 wt.% barium titanate (BT), and 20 wt.% silane-modified BT. A maximum d33 value of 13.2 pC/N was achieved through solvent casting, hot pressing, quenching, and stretching. The PVDF composites were produced using cold rolling, as tearing occurred during the stretching step. However, cold rolling negatively affected the morphology. The maximum d33 value achieved was 4.7 pC/N, observed in the MWCNT-added PVDF composites. Epoxy-based piezoelectric composites were prepared by integrating 20 wt.% PVDF (P) with 5 wt.% or 20 wt.% BT and 5 wt.% silver (S), using two curing agents of different flexibilities. The highest piezoelectric response (1.35 V) was achieved in P0BT20S0 samples cured with the more flexible agent. The lowest response (0.21 V) occurred in P20BT5S5 samples due to the agglomeration of BT and S particles. Reference P0BT0S0 samples cured with the less flexible agent showed higher glass transition temperature (81.2 °C), tensile strength (44.3 MPa), modulus (2206 MPa), and lower fracture toughness (2.0 MPa.m1/2) and fracture energy (1652 J/m2) compared to those cured with the more flexible agent. The study further examined the effect of core-shell rubber (CSR) and BT on epoxy. In the first set, 30 wt.% CSR was added with varying nano-sized BT into epoxy resin. Increasing BT content led to higher tensile modulus and crosslink density; but tensile strength, lap shear strength, and glass transition temperatures did not change significantly. Agglomerations occurred at 10 wt.% BT, slightly reducing mechanical properties. The highest fracture toughness and fracture energy were obtained with 5 wt.% BT (2.28 MPa·m1/2, 2006 J/m2), while the maximum voltage output response (0.50 V) was recorded at 20 wt.% BT. In the second set, with 20 wt.% BT and varying CSR, the compositions exhibited brittle failure. Tensile strength and modulus decreased as CSR content increased. Optimal fracture toughness and energy were achieved with 5 wt.% CSR (2.15 MPa·m1/2, 1921 J/m2), and the highest voltage response (1.85 V) was observed with 15 wt.% CSR. To extend the scope of this study, a PVDF based piezoelectric film was integrated into CFRP as a mid-layer. The PVDF+MWCNT solution was poured onto a PPS layer, dried, hot-pressed, and perforated. CFRP laminates were produced via vacuum infusion. The effects of the piezoelectric layer and perforation on performance were investigated. Flexural modulus dropped from 87.7 GPa to 72.5 GPa and 76.6 GPa with non-perforated and perforated PVDF, respectively. Despite this, the composite generated 100 mV at 0.4 Hz under a compression force of 10 N. The results showed that incorporating a PVDF-PPS layer into CFRP is promising for potential sensing applications
Developing the Entrepreneurial Paradox Mindset: The Role of Startup Accelerators and Educational Programs
No full textStartup founders often encounter paradoxical tensions. Yet, whether and how startup accelerators can equip founders to embrace such contradictions remains underexplored. Our study of Y Combinator reveals that accelerators can play a pivotal role in cultivating an entrepreneurial paradox mindset by exposing founders to teachings about paradoxical tensions, imparting heuristics to navigate them, and implementing thoughtful design choices to foster learning—particularly through vicarious and experiential learning opportunities. This study integrates paradox theory into entrepreneurship research, contributes to understanding the interplay between accelerator design choices and entrepreneurial learning, extends knowledge of entrepreneurial mindsets, and provides several practical insights.2025-09-19 JG: PDF replaced at author's requestUpdate citation details during checkdate report - RO
Last Shadow of Dáil Courts Disappears
No full textOne hundred years ago, in 1925, the last shadow of the Dáil courts disappeared. The Dáil courts are associated in popular memory with the Irish War of Independence (1919-1921). Many people think of their depiction in Ken Loach’s film The Wind that Shakes the Barley. In fact, their origins go back further
Blockchain, Recommender System, and Artificial Intelligence: Leveraging advanced digital technology for disruption risk mitigation in the medical device closed-loop supply chain
No full textMotivated by the global medical device supply chain (SC) disruption (shortage) chal-lenges triggered by the COVID-19 pandemic, in light of revolutionary trends such as the technological revolution (i.e., Industry 4.0 and 5.0), especially the rapid develop-ment of advanced digital technologies such as artificial intelligence (AI), Blockchain (BLC), Digital Twin (DT)/Simulation, and Big Data Analysis (BDA), simultaneously considering the requirements of sustainability, this thesis aims to build a resilient and sustainable medical device CLSC by leveraging advanced digital tools. This goal is achieved by (1) developing a novel BLC-based intelligent recom-mender system for SC disruption on the forward side of the medical device CLSC and (2) developing an ML-based medical device recall initiator prediction system, on the reverse side. To mitigate the disruption risk on the forward side of SC and ensure the overall CLSC operates effectively, this research first proposes a data-driven supply chain dis-ruption response framework baseline based on intelligent recommender system tech-niques. The blockchain (BLC) technology is integrated into the baseline architecture of the IRS to promise the reliability and stability of the proposed IRS as a resilient de-cision support system. The novel BLC-IRS framework can generate high-quality rec-ommendation results and identify internal and external supplementary resource infor-mation in an agile, safe, and real-time manner, thereby facilitating a higher resilience level in the physical supply chain. The BLC-IRS was implemented on a practical use case, and the information exchange mechanism in the BLC network through a smart contract was prototyped. The BLC-IRS framework was validated as an effective digi-tal SCRes measure by a System Dynamics (SD) simulation model. The simulation results demonstrate that the initial proposed BLC-IRS framework can be effectively implemented as a SC disruption mitigation measure in the SCRes response phase, enabling SC participants to better react to SC disruptions at the physical level. On the reverse side, to reduce the unexpected reverse logistics activities in the medical device sector, this research developed a machine learning-based medical de-vice recall initiator prediction framework with five algorithms to conduct proactive fail-ure detection through a practical industrial case study. In this case study, an accuracy rate of 88.18% is achieved, indicating the potential of the proposed framework in as-sisting manufacturers with asset predictive failure detection, thereby reducing recalls. A comparative analysis of prediction performance between the proposed framework and the most similar research was presented. The comparison results showed that the dataset, clustering method, and key input features chosen by this thesis are valid and efficient. The proposed predictive framework obtains higher accuracy, scalability, and practical values. The primary objective of the proposed predictive framework is to establish a sustainable and resilient supply chain utilising an intelligent decision-making support tool. This research contributes two executable digital SCRes solutions for academia and industry, as most of the previous discussions on utilizing advanced digital tech-nologies for developing SCRes are limited to the conceptual level. The deliveries of the whole research are significant from a comprehensive perspective, as this re-search is a piece of work that: (1) Considered both the forward side and reverse side of the medical device CLSC. (2) Developed SCRes with both proactive and reactive measures. (3) Combined the requirements of resiliency and sustainability