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IRS-Enhanced UAV Communication Networks: Securing Data With Hybrid Genetic and Gradient Descent Algorithms
Get PDFIn the rapidly advancing field of wireless communication, Unmanned Aerial Vehicles (UAVs) have become indispensable due to their extensive coverage capabilities and ability to access remote locations. Whether deployed as mobile base stations (BSs) or relays, UAVs significantly enhance network throughput and reliability. Alongside UAVs, Intelligent Reflecting Surfaces (IRS) have emerged as a cost-effective solution for improving communication quality through passive modulation arrays. Despite these advancements, the potential misuse of UAVs poses serious security risks, particularly in the form of communication eavesdropping. To address these challenges, this paper introduces a novel communication framework that integrates a UAV equipped with an adaptive IRS. The primary aim is to boost communication secrecy between BSs and multiple users, even in the presence of several UAV eavesdroppers. This objective is formulated as an optimization problem focused on maximizing the secrecy rate while considering UAV mobility constraints. To solve this non-convex problem, we propose a hybrid strategy that combines Genetic Algorithms and Gradient Descent techniques. This innovative approach efficiently determines suboptimal reflection angles and UAV trajectories for IRS-equipped UAVs, thereby enhancing the security of the communication network. This method not only addresses the complexity of the optimization but also provides a practical pathway to secure communications in environments with high eavesdropping risks
‘Going dark’ or under the radar? Challenges and opportunities for local authorities and dark kitchens in ensuring food safety
Get PDFTraditionally takeaway food outlets have relied on passing trade or it was included as part of a restaurant’s offering. Yet the surge in online applications for ordering food has challenged this operational model. The rise of so-called dark kitchens that have no physical customer-facing presence has revolutionised the takeaway food sector. This change comes with a unique set of challenges and opportunities for food safety inspections and implementations. This study aims to assess the challenges in identifying and regulating dark kitchens, and to identify potential interventions to increase food safety compliance in dark kitchens by working with local authorities and dark kitchen owners and tenants. A mixed-method study involving a cross-sectional survey (n=123) and two focus group discussions with 16 Environmental Health Officers (EHOs) and 16 semistructured interviews with dark kitchen owners and tenants were conducted in England. Our study revealed multiple challenges faced by dark kitchen operators in managing food safety in shared spaces, food handling during delivery, high turnover of staff and delays in updating menu changes with online aggregators. The latter part of our study highlights the challenges encountered by EHOs in identifying and inspecting dark kitchens; including resource constraints, lack of dark kitchens’ visibility, multiple trading names, insufficient guidance from regulatory body, communication difficulties, difficult working conditions in some dark kitchens and problems identifying where responsibility lies. Based on the perspectives of EHOs and dark kitchens, practical recommendations to improve food safety standards of dark kitchens are provided. The study also highlights the important role the online aggregators play in supporting Local Authorities as they have the ability to monitor and ensure rigorous vetting of food businesses before onboarding the food business. This is the first empirical study to assess the challenges in identifying and regulating dark kitchens as well as to identify the challenges and opportunities for food safety implementation and inspection in dark kitchens
Integrating Multidisciplinary DBR in Mechanical Engineering Education, Challenges, and Opportunities
No full textThis chapter explores the challenges and opportunities of integrating multidisciplinary design-based research (DBR) into mechanical engineering education. As engineering problems become more complex, there is a growing need for graduates who can work across disciplines. DBR enhances the mechanical engineering curriculum by fostering collaboration, promoting real-world problem-solving skills, and bridging theory and practice. The chapter addresses challenges in implementing DBR, including resistance to change, resource constraints, and assessment issues, while highlighting opportunities for improved student engagement, creativity, and industry partnerships. Case studies of successful DBR integration in mechanical engineering programs are presented, showcasing innovative approaches and outcomes. Finally, the chapter proposes strategies to overcome barriers and maximize the benefits of multidisciplinary DBR, contributing valuable insights for educators seeking to prepare students for the evolving demands of the engineering profession
“Yes, everyone is blindfolded but that doesn’t make it equal”: the intersectional experiences of visually impaired women footballers in England.
Get PDFIn recent years there have been concerted global efforts to develop women’s visually impaired (VI) football. However, these developments have not occurred without challenges and the players’ experiences during this significant period of progress have received no academic attention. We adopt an intra-categorical complexity approach to intersectionality to explore VI women’s experiences of becoming and being footballers. The study utilises a focus group and in-depth semi-structured interviews with a purposive sample of seven women, with differing sight conditions, who have participated in VI football in England. Using abductive analysis, we examine how the players’ lived experiences have been shaped by the complex intersections of being female, disabled and, more specifically, VI. Our analysis reveals that these intersections create inequitable outcomes for footballers with various subordinate identities. The main inequities derive from the historic marginalisation of women in disability football and include the challenges of learning a new sport, players with different sight conditions adjusting to wearing blindfolds in blind football, and tensions between players brought about by the combination of B1-B3 classes. The findings reveal complex lived realities of VI women footballers, which have implications for key stakeholders tasked with growing the game in a manner that leads to more equitable outcomes for VI women
A Transdisciplinary Study of Global Mobilities: Identities on the Move
No full textIdentities on the Move interrogates the categories given and adopted by people on the move through a transdisciplinary and global approach that includes social and political sciences and the arts. It brings together experiences of displacement from a variety of cultural and national backgrounds, including Brazilians, Chinese, Koreans, South Italians, Africans, Muslims, Arabophobe migrants, Iranians, Pakistanis, Bosnians, Latin Americans and Eastern Europeans. It looks at their identity-negotiating processes in different geographies across the globe, namely Japan, UK, Palestine, Italy, Australia, Europe and North America. This multi-geographical and multi-disciplinary approach allows us to decentralise previous narratives of migration by reformulating them against coloniality and invisibility and presenting them within a richer and changing contemporary map of dynamic identities. The global scale of the case studies included in this volume also allows for a wider exploration of thematic concepts within the (trans)formation of displaced identities, such as assimilation versus alienation, memory and trauma, stigmatisation, enculturation, acculturation and deculturation. In a nutshell, this volume highlights current complexities of identity formation in a global scene that is moving away from homogenous nations by presenting a multi-layered and multi-spatial notion of belonging
Vertical movement of head, withers and pelvis of high level dressage horses trotting in-hand vs. ridden
Get PDFPrior to international competitions, dressage horses are evaluated for fitness to compete while trotting in hand on a firm surface. This study compares the kinematics of experienced dressage horses trotting under fitness-to-compete conditions vs. performing collected and extended trot when ridden on a sand-fiber arena surface. The hypotheses are that the vertical range of motion (ROM) and left–right asymmetries in minimal and maximal heights of axial body segments at ridden trot exceed those when trotting in hand. Inertial measurement units (IMUs) attached mid-dorsally to the head, withers, and pelvis of 19 actively competing dressage horses measured the vertical ROM and left–right asymmetries in minimal (MinDiff) and maximal (MaxDiff) heights of the midline sensors. The vertical ROM was greater for both types of ridden trot, reflecting greater impulsion in response to the riders’ aids. Head MinDiff/MaxDiff and withers MaxDiff were significantly higher under both ridden conditions. Pelvis MinDiff was significantly the largest for collected trot. Compared with trot in hand, left–right differences in limb protraction were larger for extended and collected trot in the forelimbs but only for extended trot in the hind limbs. The rider’s influence increases the horse’s impulsion and vertical ROM, which may exacerbate inherent asymmetries in muscular strength when lowering the haunches and elevating the withers
Exploration of running in minimal and conventional footwear on tibial stress fracture probability in habitual and non-habitual minimal users
Get PDFThis research sought to investigate the impact of minimal and conventional footwear on the likelihood of tibial stress fractures among individuals who habitually and do not habitually use minimal footwear. Ten males who habitually ran in minimal footwear and ten males who habitually ran in conventional footwear, took part in this investigation. Kinematic information during over-ground running were gathered using an eight-camera motion-capture system, and ground reaction forces were recorded using a force plate. Tibial strains were assessed through finite element model-ling, while the likelihood of stress fractures was determined through probabilistic modelling across a 100-day running period. Medial tibial loads were significantly greater in minimal footwear in both habitual (minimal = 1.27 & conventional = 1.09 BW) and non-habitual runners (habitual: minimal = 1.36 & conventional = 1.10 BW). There were however no significant differences between footwear or between habitual and non-habitual minimal footwear groups in 90th percentile tibial strain (habitual: minimal = 3894.45 & conventional = 3691.70 με and non-habitual: minimal = 4047.03 & conventional = 3787.73 με). Furthermore, tibial stress fracture probability also did not differ significantly between footwear or between habitual and non-habitual minimal footwear groups (habitual: mini-mal = 9.81 & conventional = 10.62% and non-habitual: minimal = 12.08 & conventional = 13.63%). This investigation, therefore, indicates that neither habitual and non-habitual minimal footwear users nor minimal and conventional footwear appears to significantly affect the probability of developing a tibial stress fracture in experienced runners
Thermodynamic properties of hydrogen containing systems and calculation of gas critical flow factor
Get PDFSonic nozzles are emerging as crucial reference devices in the calibration of flow meters designed for hydrogen service. In this research study we aim to investigate existing equations governing the critical flow factor (C∗) for hydrogen and assess the achievable uncertainty in determining this vital property. An examination of the literature has been undertaken to target experimental measurements related to hydrogen mixtures, setting the stage for a comprehensive gap analysis.
We introduced C∗ values and validated our calculations with two calibration gases: nitrogen, and methane and their standardised C∗ values. Then, the verified methodology has been utilised for generating C∗ values for hydrogen.
This study concluded that the integration of precise experimental data and the utilisation of representative equations and optimised thermodynamic models is essential for enhancing the accuracy of C∗ calculations, particularly in the context of the expanding role of sonic nozzles in hydrogen flow meter calibration
Magnetic fields on different spatial scales of the L328 cloud
Get PDFL328 core has three sub-cores S1, S2, and S3, among which the sub-core S2 contains L328-IRS, a Very Low Luminosity Object (VeLLO), which shows a CO bipolar outflow. Earlier investigations of L328 mapped cloud/envelope (parsec-scale) magnetic fields (B-fields). In this work, we used JCMT/POL-2 submillimeter (sub-mm) polarisation measurements at 850 μm to map core-scale B-fields in L328. The B-fields were found to be ordered and well-connected from cloud to core-scales, i.e., from parsec- to sub-parsec-scale. The connection in B-field geometry is shown using Planck dust polarisation maps to trace large-scale B-fields, optical and near-infrared (NIR) polarisation observations to trace B-fields in the cloud and envelope, and 850 μm polarisation mapping core-scale field geometry. The core-scale B-field strength, estimated using the modified Davis-Chandrasekhar-Fermi relation, was found to be 50.5 ± 9.8 μG, which is ∼2.5 times higher than the envelope B-field strength found in previous studies. This indicates that B-fields are getting stronger on smaller (sub-parsec) scales. The mass-to-flux ratio of 1.1 ± 0.2 suggests that the core is magnetically transcritical. The energy budget in the L328 core was also estimated, revealing that the gravitational, magnetic, and non-thermal kinetic energies were comparable with each other, while thermal energy was significantly lower