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Large-Scale Agile Project Management in Safety-Critical Industries:A Case Study on Challenges and Solutions
Get PDFWhile agile project management offers benefits such as faster time to market and improved collaboration, scaling it to larger projects presents challenges, particularly in safety-critical industries. This research provides insights into the resistance to agile adoption due to regulatory constraints and other barriers. The findings contribute to information systems literature by identifying four challenges (organizational, technological, behavioral, regulatory) and complementing solutions to show how large-scale agile can work in safety-critical industries
Developing citizen science ecosystem:critical factors for quadruple helix stakeholders engagement
Get PDFPurpose: The purpose of this paper is to provide answers regarding the factors that motivate or discourage the quadruple helix (QH) stakeholders and the wider public in citizen science (CS) activities. The research reveals a current overview of the perceptions, attitudes, concerns and motivation with regard to development of CS ecosystem in four countries: Greece, Lithuania, the Netherlands and Spain. Design/methodology/approach: The researchers deploy a mixed methodology, entailing an in-depth literature review and a large-scale quantitative survey (approximately 2,000 citizens) targeting QH stakeholders and general public from the local national ecosystems. The results contain both descriptive statistics and statistical analysis per country. After the comprehensive overview of drivers and barriers regarding the participation in CS activities in general, the focus is narrowed down on the engagement motivation of different QH stakeholders and the differences in enabling/hindering factors at the local ecosystems. Findings: Depending on the country and the pre-existing level of CS maturity, the results provide a complicated network of factors that unlock or block participation in CS activities. These factors include, to name a few, political maturity, civic engagement, technological infrastructures, economic growth, culture of stakeholder collaboration, psychological stimulus and surplus of resources. The implications of the findings necessitate the alignment of the envisioned CS ecosystem with the local dynamics in each country. Research limitations/implications: The quantitative nature of the survey method, limited sample size and only four countries context are noted as limitations of the study and offer future research potential for longitudinal settings and mixed-methods studies. Originality/value: The results contribute to the wider literature on CS that focuses on perspectives, possibilities and differences in local contexts with respect to the public engagement by developing CS ecosystem. At the same time, its added value lies in the overall practical proposition, and how the latter can effectively and efficiently attract and retain different stakeholder groups and citizens, under a collaborative approach.</p
Improved Low-Temperature CO Oxidation using Heterogeneous Nanofibrous Structures Decorated with Pd Atoms and Nanocrystals
No full textAmorphous alumina shaped as nanofibers forming a non-woven network, functioning as a heterogeneous dispersion for palladium (Pd) atoms and nanocrystals, is unique yet unstudied for low-temperature CO oxidation. This work demonstrates that nanometric-size alumina fibers (ANFs) with a surface area of ⁓230 m2/g can host Pd species that remain nearly intact after CO oxidation. The ANFs contain various Pd (Pd-ANFs) loadings, ranging from 1%wt. (Pd1-ANFs), 3%wt. (Pd3-ANFs), to 5%wt. (Pd5-ANFs). Among them, Pd3-ANFs show the highest CO chemisorption. Hence, the chemical environment of the Pd3-ANFs is assessed using NAP-XPS under various CO and O2 mixtures. NAP-XPS shows the presence of metallic and oxidized Pd species. The results are correlated with DRIFT spectroscopy, which unveils the CO species adsorbed over Pd. Furthermore, a computational-based kinetic model for CO oxidation shows that Pd single atoms start the CO-oxidation, followed by larger Pd crystals during light-off. Our results demonstrate that the Pd-ANFs have higher activity when compared with the Pd alumina nanoparticles (Pd-ANP) counterpart that lacks a fibrous structure, highlighting the benefits of the ANF's structural network in stabilizing atomic and nanometric scale metal catalysts for low-temperature CO oxidation
A New Silicon Accumulation-Mode Trench Bidirectional Switch
No full textThe bidirectional switch, or bidiswitch, is a key component widely used for battery protection. During charging and discharging of the battery, the bidiswitch should be able to handle sufficient current and to block high voltages all in both the directions. In this work, we propose a new type of silicon bidiswitch: the accumulation-mode trench bidiswitch (AM bidiswitch). Due to aggressive cell dimensions (≤ 0.6 μm), both the accumulation-mode field effect and the reduced surface field (RESURF) effect can be adopted, so that no separate p-body connection is required, and consequently, minimal specific on-resistances (R on,sp) and even minimal leakage currents (I rev) can be obtained. Based on a theoretical framework, an optimization guideline is presented using TCAD simulations. The results show R on,sp values ranging from 3.5 to 10.8 mΩ·mm 2 for stripe (or 2-D) structures and 6.5 to 45.6 mΩ·mm 2 for gate-all-around (GAA) structures, with breakdown voltages (BVs) ranging from 25 to 75 V. For high temperatures (T = 425 K), the obtained minimal I rev ranges from 0.75 to over 5 mA for the stripe structures and from 0.1 to 0.4 mA for the GAA structures both for an active device area of 1 mm 2.</p
Comprehensive monitoring and prediction of seismicity within the Groningen gas field using large-scale field observations
Get PDFThis dissertation addresses the critical issue of induced seismicity within the Groningen gas field, one of the largest natural gas reservoirs globally. Since its discovery in the 1960s, the Groningen field has played a pivotal role in meet- ing the energy needs of the Netherlands. However, decades of sustained gas extraction have resulted in significant seismic activity in what was previously a tectonically inactive region. These induced earthquakes have raised press- ing public safety concerns, necessitating a comprehensive understanding of the underlying processes, alongside the development of robust methodologies for monitoring and predicting seismic events. The aim of this research is to advance the monitoring, analysis, and pre- diction of seismicity by integrating statistical models with geomechanical in- sights and decision-making frameworks. Specifically, this study seeks to analyse the spatial and temporal patterns of seismic activity, predict future earthquake occurrences using spatio-temporal models, and optimise production strategies while mitigating seismic risk. Conducted within the framework of the DeepNL programme by the nwo (nwo), this work forms part of a broader effort to deepen understanding of subsurface dynamics influenced by anthropogenic activities. A multidisciplinary methodological approach was employed to achieve the study objectives. The research relies on an extensive dataset comprising seis- mic event records provided by knmi (covering magnitudes ≥ 1.5 from 1995 to 2023), historical gas production data, pore pressure measurements from bore- holes, and NAM’s dynamic reservoir model output. Rigorous data cleaning and integration procedures ensured the datasets’ reliability, which formed the basis for subsequent statistical analyses. The study begins with a detailed temporal and spatial analysis of seismic activity. Temporal trends were examined using Poisson point processes, which allowed for the identification of earthquake timing patterns. Moreover, adap- tive kernel estimation techniques were employed to detect spatial clustering of seismic events, particularly in regions experiencing significant pore pressure de- pletion. Building upon these initial analyses, spatio-temporal Cox processes were applied to model earthquake intensity more comprehensively. This ap- proach was enhanced by incorporating covariates derived from pore pressure estimates using polynomial kriging and Bayesian inference methods, thereby improving the predictive accuracy of seismic hazard assessments
Do urban digital twins need agents?
Get PDFThe urban digital twin (UDT) is derived from the original digital-twin concept of a representation of physical assets. This has left the social component of the city underrepresented in UDTs. Here, we discuss what this means for the current maturity stage of UDTs and why better representing human behaviour in UDTs may diversify possibilities to support different types of planning. We contemplate operationalizing the representation of human behaviour by means of agent-based models (ABMs) integrated with UDTs and illustrate this with two concrete examples of simulating stress and safety perception in public spaces. One example shows the idea of the UDT as a live data repository for ABMs, with the ABM adding dynamism, and the other of live feedback between the city, the ABM and UDT. We discuss several epistemological, conceptual, technical, and ethical challenges that may be involved in this integration. We conclude with a future agenda to promote (1) the abandonment of the vision of a UDT as the highly detailed mirror of the city, (2) UDTs fit for sectoral (strategic) in addition to operational planning, (3) the inclusion of behavioural and social processes in UDTs by incorporating ABMs, (4) a culture of cumulative research using structured guided frameworks and reusable building blocks, (5) ABMs with explicit purposes to allow fit-for-purpose selection in UDTs, and (6) explicitly addressing epistemic, normative, and moral responsibilities. Thus, though including agents may at some point be a solution for the (currently lacking) perspective on the role of humans in shaping and being shaped by the city, several reconsiderations in the UDT and ABM communities need to take place first.</p
Explicit Values of Bernoulli Polynomials at Rational Numbers
No full textWe give an explicit formula for the value of the Bernoulli polynomial B2k(t) when t is a rational number in the interval (0,1). When t=12,13,23,14,34,16,56 the value of B2k(t) is known explicitly. In 1938 Emma Lehmer asked for the value of B2k(t) when the denominator of t is 5, 8, 10, or 12. We apply our formula to determine B2k(t) when the denominator of t is 5, 8, 10, and 12 thereby answering Lehmer's 87 year old question.<br/
Patching up finger vein recognition:An unsupervised approach using local information for robustness
Get PDFIn the era of heightened security and privacy concerns, finger vein recognition presents a significant advantage over traditional biometric methods like facial and fingerprint recognition. Unlike fingerprints and facial features, which can be easily captured or replicated, vein patterns are hidden beneath the skin, making them resistant to theft and forgery. This makes finger vein recognition a promising technology for high-security applications.However, several challenges hinder its widespread adoption. These include limited labelled data, difficulties in generalising learned representations, and the lack of comprehensive image quality assessment methods. Finger vein datasets are relatively small, making deep learning approaches reliant on transfer learning from natural image datasets. While this technique achieves state-of-the-art performance on individual datasets, it struggles with cross-dataset generalisation, limiting its effectiveness in real-world applications where multiple devices are involved. Additionally, current image quality assessments often focus on general image attributes like sharpness and contrast, overlooking their actual utility in recognition.To address these challenges, this thesis explores alternative approaches for improving the reliability and robustness of finger vein recognition. An unsupervised auto-encoder model is proposed to learn meaningful representations without requiring large datasets. However, it struggles with distinguishing vein structures due to the dominance of background patterns. To overcome this, a patch-based approach is introduced, dividing images into smaller sections to enhance training variability and reduce background interference. This approach outperforms traditional deep learning models and maintains consistent performance across unseen datasets.For cross-device recognition, a novel dataset comprising images from six different devices is introduced. The results show that device variations impact recognition performance, but the patch-based auto-encoder achieves superior generalisation compared to traditional and deep learning methods. This highlights the need for standardised acquisition protocols for improved interoperability.Finally, a patch-based quality assessment method is developed, focusing on vein visibility and diversity to ensure reliable recognition. Evaluations demonstrate its effectiveness in detecting poor-quality samples, enhancing system security.Overall, this research advances finger vein recognition technology, offering insights into its robustness, generalisation, and quality assessment, with potential for real-world applications
China’s Belt and Road Initiative is Not a Novel Approach to International Law-Making
Get PDFThe Belt and Road Initiative (BRI) has advanced in various regions. While analyses have predominantly focused on its political and economic impacts, its legal aspects received less attention. This article explores whether the Chinese legal model implemented via the initiative represents a novel approach to international law-making. The focus is on its application in theMiddle East andNorth Africa, where a set of primary mechanisms are utilised: soft law instruments that establish a theoretical and practical framework for collaboration. The author provides a comparative analysis of the European Union (EU) and United States (US) legal models, considering the overall pros and cons of Beijing’s strategy. The article concludes that while these mechanisms represent a pragmatic governance model relying on flexible rules, they are not a novel approach. The US and the EU have employed such soft lawinstruments, under which binding agreements were established to ensure formal commitments