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A data-centric approach to terminal unit’s fault categorization and optimal positioning in building HVAC systems using ensemble learning
Get PDFThis paper focuses on the fault detection and diagnosis of terminal units (TUs) in a building located in London, utilizing real operational historical data to assess their performance and optimal placement across multiple floors. While precise locations of the TUs are unavailable, our method analyzes their operational behaviour for one month, applying popular machine learning models to detect and analyze faults effectively. By examining each TU individually and in the aggregate, we identify behavioural patterns that inform decisions regarding their positioning within the building. The dataset comprises over 2 million data points collected from 730 TUs, enabling a comprehensive analysis of their functionality and the impact of suboptimal thermostat placements. Our study employs three machine learning models-traditional multi-class Support Vector Machines and two ensemble methods: Random Forest (RF), and Adaptive Boosting (AdaBoost)-to classify TU behaviors into normal operation, heating faults, and cooling faults. Results indicate that RF outperforms the other models with an accuracy of 99.89%, while AdaBoost achieves an accuracy of 85% and SVM shows 47% accuracy. The findings underscore the potential of a data-driven approach to inform retrofitting decisions and enhance the reliability of HVAC systems. This research contributes valuable knowledge toward optimizing TU placement, ultimately leading to improved energy efficiency and indoor environmental quality
Metasurface effect on the performance of planar antennas for wireless communications
Get PDFThis paper demonstrates the performance enhancement of a conventional planar antenna by incorporating metasurface (MTS) layer using a proposed unit‐cell array. The impact of MTS unit‐cell density on bit‐error‐rate (BER) and channel capacity (CC) in a point‐to‐point microwave link is investigated. The MTS layer is constructed from an array of identical unit‐cells, including circular, square, and Jerusalem cross microstrip‐line elements. The proposed H‐shaped checkerboard antenna design is integrated with the MTS and evaluated for various unit‐cell densities. Analytical scrutiny reveals significant enhancements in BER and CC with higher MTS unit‐cell density, along with an increase in antenna gain through optimal MTS placement. This improvement is attributed to the MTS's ability to concentrate radiated energy within a narrower spatial region, optimizing signal transmission. Experimental validation shows a strong correlation between analytical predictions and measured results, confirming the effectiveness of our methodology. This study not only highlights the impact of MTS configurations on wireless channel performance but also provides valuable insights into the design and optimization of future wireless communication systems
A Christocentric theology of vaccination: a pastoral resource for navigating science and faith
Get PDFThis study aims to provide a Christocentric theological and pastoral framework for understanding vaccination, offering a theological and epistemological tool (Theological Epistemology) that distinguishes observation and reason (OR) from beliefs inconsistent with biblical doctrine, thereby enabling trust in the veracity of scientific OR. This study is motivated by two pressing concerns within the Christian community: a growing mistrust of scientific observation and reason (OR), particularly regarding vaccination, and a theological gap in understanding how vaccination aligns with Christ’s redemptive mission. The study critiques existing theological literature on vaccination, identifying gaps in either scientific or theological rigour. In response, this study proposes a balanced integration of theological and scientific reasoning (Theological Reflection), presenting vaccination as participation in Christ’s redemptive mission to “destroy the works of the enemy” (1 John 3:8). Public health successes, such as smallpox eradication, are framed as missional acts, supported by scientific observation and reason (OR) that reinforce the theological argument. The paper responds to common objections (Systematic Theology), including concerns about aborted foetal cell lines, bodily sanctity, divine healing, and moral implications of certain vaccines, through biblical reasoning and pastoral sensitivity. Thus, the method is a three-step process: Theological Epistemology, Theological Reflection and Systematic Theology. This Christocentric framework enables church leaders to guide congregations toward informed, compassionate vaccination choices, aligning with their missional and pastoral responsibilities. This significance lies in its potential to foster faith-informed public health engagement and promote life-affirming theological reflection
Scaffolds for teachers' integration of social justice issues in mathematics education: a pilot study
No full textIn this article we report on a pilot study conducted in the Philippines in which the aim was to investigate the scaffolding that mathematics teachers needed to participate in a project in which social justice issues were incorporated in their classroom activities. We collaborated with 2 mathematics teachers at public high schools to implement activities developed by us in which social justice issues were integrated in their mathematics classes. We then interviewed the teachers to gain insight into (1) the teachers’ decisions and actions during the implementation of these activities, and (2) their learners’ experiences and views working on such mathematics activities. Based on an analysis of their interview responses, it was found that both the teachers and learners welcomed the incorporation of social justice themes in their lessons. However, it was also found that teachers required more support to develop their agency in two main areas: (1) crafting contextualised mathematics activities incorporating social justice issues, and (2) creating learning environments that develop learners’ agency to participate effectively in such activities
System inertia cost forecasting using machine learning: a data-driven approach for grid energy trading in Great Britain
Get PDFAs modern power systems integrate more renewable and decentralised generation, maintaining grid stability has become increasingly challenging. This study proposes a data-driven machine learning framework for forecasting system inertia service costs - a key yet underexplored variable influencing energy trading and frequency stability in Great Britain. Using eight years (2017–2024) of National Energy System Operator (NESO) data, four models - Long Short-Term Memory (LSTM), Residual LSTM, eXtreme Gradient Boosting (XGBoost), and Light Gradient-Boosting Machine (LightGBM) - are comparatively analysed. LSTM-based models capture temporal dependencies, while ensemble methods effectively handle nonlinear feature relationships. Results demonstrate that LightGBM achieves the highest predictive accuracy, offering a robust method for inertia cost estimation and market intelligence. The framework contributes to strategic procurement planning and supports market design for a more resilient, cost-effective grid
Religion, morality, and democracy in Ghana
Get PDFMany Ghanaians express concern about what they regard as a serious decline in morality and integrity, at both elite and popular levels. The decline is believed to fuel corruption, undermine national development, and diminish faith in democracy as the best available system of government. The paper argues that a close relationship between Ghana’s largest church, the Church of Pentecost (CoP), and the country’s two main political parties, the New Patriotic Party and the National Democratic Congress, threatens Ghana’s secular constitution and the country’s three decades of democracy in two ways. First, the CoP wants undemocratically to impose a framework to control Ghanaians’ moral behaviour according to the church’s values and beliefs. Second, the CoP’s influence on Ghana’s two main political parties seeks to prioritise power and control over all Ghanaians regardless of their religious affiliation and of the country’s commitment to democratic norms and institutions
Secure satellite downlink with hybrid RIS and AI-based optimization
Get PDFIn this paper, we explore a secure multiuser multiple-input single-output (MISO) satellite downlink communication system, enhanced by the integration of a hybrid reconfigurable intelligent surface (RIS). The study formulates a robust joint design for satellite and RIS beamforming, aimed at maximizing the secrecy rate of the overall system. Both the active and passive elements of the RIS are optimized, taking into account practical models that reflect real-world constraints, such as outdated channel state information (CSI) and the power consumption of the system. To address the highly complex, dynamic, and multidimensional nature of the beamforming design problem, deep reinforcement learning (DRL) techniques are employed. Simulation results demonstrate the effectiveness of the proposed beamforming strategy, highlighting significant performance improvements when utilizing hybrid-RIS compared to traditional passive RIS solutions in wireless communication systems
The temporality of building: European and Chinese perspectives on architecture and heritage
No full textThis book examines the role that time plays in the life of buildings, adopting a comparative study of this influence between European and Chinese traditions. Whilst issues of time in architecture have attracted increasing interest by academics in the West, challenging the dominant modernist precepts of space, there is little understanding of the subject in China and how these compare to historical and contemporary perspectives in Europe. A guiding premise of the investigation is that notions of building time require insight into how cultural habits commingle with natural rhythms, or what David Leatherbarrow calls “concurrency”.
Rather than examining specific buildings, the first three chapters apply three key themes (language, ritual and heritage) as cultural lenses to reveal differences and similarities between the two traditions. Through these lenses, buildings, interiors and their exterior spaces (churches/cathedrals, temples, palaces, gardens and courtyard houses) are explored to demonstrate how building time involves particular situations/settings and their correlating relationships to past traditions. In the final chapter we consider notions of time in the context of contemporary buildings in Europe and China, drawing on the earlier historical investigations and addressing globalising influences.
This book would be of interest to architects, architectural theorists, historians, philosophers, sociologists and anthropologists
Label flipping attacks in hierarchical federated learning for intrusion detection in IoT
No full textFederated learning (FL) is a promising approach for distributed training of deep neural networks within Internet of Things (IoT) environments, where the data generated by IoT devices stays local, and only model updates are communicated to a central server. This methodology is particularly relevant for intrusion detection systems in IoT networks, where security is paramount. However, the decentralized nature of FL introduces vulnerabilities, such as the risk of data poisoning by malicious participants. In this paper, we propose a hierarchical federated learning to reduce communication overhead and improve privacy by limiting data spread. We further explore the impact of label-flipping attacks on hierarchical FL systems used in IoT-based intrusion detection. We focus on scenarios where a subset of malicious participants attempts to degrade the global model’s performance by submitting corrupted model updates based on intentionally mislabeled data. Our findings reveal significant decreases in classification accuracy by 10.53% and recall rates, even with a minimal number of compromised participants, primarily affecting the specific classes targeted by the attackers. We further examine how the availability of these malicious nodes influences the attack’s success. To counteract these threats, we introduce a defense mechanism that successfully identifies all rogue participants and mitigates their impact. As a result, the global model’s accuracy is maintained at the original 95% level found during training without the presence of malicious clients, thereby enhancing the resilience of federated learning models in IoT security applications
Clay ingestion adverse health experiences during pregnancy among African women in London
Get PDFBackground/Aims: Scientific evidence points to the health risks associated with clay ingestion during pregnancy. However, little is known about African migrant women’s self-reported adverse health experiences from the practice, as well as adapted mitigating measures. This study aimed to explore these experiences to diversify the knowledge base.
Methods: This qualitative study used an interpretative phenomenological approach. Data were gathered from a purposive sample of 30 participants through individual semi-structured interviews. The data were analysed thematically.
Results: Self-reported adverse health experiences were mainly constipation and iron deficiency anaemia. Remedies applied included increased fibre and water intake, a traditional herb-clay mixture and medical interventions in the form of constipation pumps and laxatives. Anaemia resulted in blood transfusion and iron infusion in some cases.
Conclusions: Despite the known risks or drawbacks, many women continued to ingest clay during pregnancy, as it was a traditional or cultural practice in their communities. This could cause effects severe enough to merit medical intervention. Implications for practice: Community-led interventions in collaboration with public health authorities and practitioners that engage women regarding the potential health risks for mothers and their babies should be prioritised