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Shifts on trees versus classical shifts in chain recurrence
No full textWe construct continuous (and even invertible) linear operators acting on Banach (even Hilbert) spaces whose restrictions to their respective closed linear subspaces of chain recurrent vectors are not chain recurrent operators. This construction completely solves in the negative a problem posed by Nilson C. Bernardes Jr. and Alfred Peris on chain recurrence in Linear Dynamics. In particular: we show that the non-invertible case can be directly solved via relatively simple weighted backward shifts acting on certain unrooted directed trees; then we modify the non-invertible counterexample to address the invertible case, but falling outside the class of weighted shift operators; and we finally show that this behaviour cannot be achieved via classical (unilateral neither bilateral) weighted backward sifts (acting on N and Z respectively) by noticing that a classical shift is a chain recurrent operator as soon as it admits a non-zero chain recurrent vector
The case for audio-first mixed reality: an AI-enhanced framework
No full textCurrent mixed reality (MR) interfaces predominantly rely on visual modalities, creating fundamental limitations in high-stress scenarios and detail-critical applications. This position paper challenges the visual-first paradigm in MR interfaces by proposing a shift toward audio-centric interaction supported by artificial intelligence. We argue that the convergence of three key developments - advances in spatial audio processing, the emergence of powerful language models, and the increasing sophistication of retrieval-augmented generation - creates a unique opportunity to reimagine MR interfaces. We present a conceptual framework for an Audio-Based Situated Analytics system that prioritizes auditory interaction while reserving visual channels for essential tasks. Drawing from research in audio augmented reality, situated analytics, and AI, we explore how this paradigm shift could transform critical applications such as first response scenarios and cultural heritage experiences. This study aims to spark discussion in the MR community about the role of audio interfaces, outline key research challenges, and propose a roadmap for future investigation. By challenging current assumptions about MR interface design, we hope to encourage new directions in research that could lead to more effective, inclusive, and less cognitively demanding MR experiences
Breaking barriers in accessibility: mobile AR solutions for home assessments
No full textThis study evaluates augmented reality (AR) tools for spatial measurement in the Augmented Reality Home Assessment Tool, designed for consumer-grade mobile phones. The tool provides a reliable home assessment method based on residents’ functional limitations. A mixed-methods study with a convergent parallel design compared AR and traditional methods across speed, accuracy, ease of use, and user confidence. Learnability was tested through repeated measures with 32 participants in a within-subjects design. Results showed AR tools were faster, more accurate, easier to use, and boosted confidence, though a slight learning curve was noted. Qualitative methods, including think-aloud protocols, interviews, and observations, identified usability concerns related to information accessibility, user control, and cognitive aspects. Findings highlight the potential of phone-based AR for identifying residential barriers, supporting high-quality self-assessment for users familiar with mobile technology
Rapid and sensitive biosensing of uropathogenic E. coli using plasmonic nanohole arrays on MIM: bridging the gap between lab and clinical diagnostics
No full textThis study introduces a novel biosensing platform, Plasmonic Array Nanohole Technology on Metal-Insulator-Metal (PANTOMIM), designed to overcome limitations of traditional plasmonic nanohole array biosensors. PANTOMIM utilizes a metal-insulator-metal structure as a lossy waveguide to dampen metal/substrate peaks, ensuring high extinction coefficients and spectral purity for biosensing. The architecture is optimized for the 800–850 nm wavelength range, with potential for future integration into nanophotonic devices. To demonstrate its clinical utility, we applied PANTOMIM to the detection of uropathogenic Escherichia coli (UPEC) in urine samples. This approach addresses the need for rapid diagnosis of urinary tract infections, providing results in 15 min and requiring minimal sample preparation. The efficacy of the technology was validated in a clinical setting with a cohort of 100 patients, showcasing its potential to revolutionize the detection of UPEC. PANTOMIM combines the advantages of plasmonic nanohole arrays, including tunable periodicity, coupled plasmonic response, and extraordinary optical transmission, while mitigating the challenges associated with thin-film plasmonic metals. This innovation paves the way for integrated nanoplasmonic biosensors for point-of-care diagnostics
Angle-based multi-goal ordering and path-planning using an improved A-star algorithm
No full textIn the field of autonomous mobile robotics, the demand for highly efficient path-planning algorithms is crucial. Among the various path-planning tasks and challenges, multi-goal path planning stands out as a particularly complex problem, where the objective is to determine the most efficient path for a robot to visit multiple goal nodes. In this paper, we introduce a novel ordering algorithm designed to optimize the sequence in which the goal nodes are visited. The ordering is based on a one-distance-two-angles ordering paradigm, which reduces the dependency on distances as deciding factors and incorporates more angles to gather the necessary information, thereby reducing the computational complexity of the overall ordering procedure. The backbone of the algorithm is an improved version of the A* search algorithm that we developed to further reduce the distance cost of the original A* algorithm by solving some internal issues caused by the nature of the algorithm when dealing with grid-based environments. Extensive experiments were conducted to demonstrate the computational efficiency and cost-effectiveness of our proposed algorithm. The scalability and reproducibility of the proposed ordering algorithm and the improved A* were validated by testing them on various publicly available maps in numerous different scenarios. We also performed comprehensive comparisons with existing state-of-the-art algorithms to evaluate the performance. The conducted experiments report that our proposed algorithm consistently outperformed other algorithms in numerous scenarios, underscoring its reliability and potential to match or even exceed the performance of current state-of-the-art methods in the domain of multi-goal path planning. The entire code, map and other resources of our proposed algorithms are available at https://github.com/abdullah1aloush1/AMuGOPIA
The local well-posedness for the dispersion generalized Camassa-Holm equation
No full textIn this paper, we establish the local well-posedness of the Cauchy problem for a dispersion generalized Camassa–Holm equation. The present generalization is obtained by replacing the operator (Formula presented.) of the Camassa–Holm equation with (Formula presented.) where L is a positive differential operator with order p, an even positive integer. We follow Kato's semigroup approach for quasi-linear evolution equations but use L-dependent operators and norms. We show that the Cauchy problem is locally well-posed in a Banach space for which the norms are equivalent to Sobolev space norms and the regularity index has a threshold depending on p. Considering the special cases of the operator L, we verify that our results are consistent with those presented in the literature
Human factors in phishing: understanding susceptibility and resilience
No full textThis study examines the demographic and organizational factors influencing phishing susceptibility and incident reporting behaviors among employees in a large European financial organization following realistic phishing simulations and how these factors correlate with susceptibility to phishing attacks. In the phishing simulations campaign with 8,102 participants, unannounced, monthly phishing emails with different templates are sent during regular work hours over a duration of 2 years, and the reactions (clicking the link and reporting the phishing email) are collected. The results are combined with demographic and relevant organizational data such as age, gender, level of education, department type, tenure, and job level. Multivariate logistic regression models are developed to analyze the relationship between these variables and phishing behaviors. The analysis reveals significant differences in susceptibility to and resilience against phishing attacks across various demographic and organizational groups. Older employees are more susceptible to phishing, while males show lower vulnerability to phishing attacks. Additionally, our results revealed that higher-level employees often under report phishing emails. These findings highlight the necessity for targeted anti-phishing training tailored to different demographics and departments within the organization and the importance of fostering a culture of incident reporting. Recommendations include customized cyber awareness training programs, regular awareness sessions, and incentivizing reporting. Future research is encouraged to prioritize investigating the root causes of phishing behaviors and evaluating the effectiveness of training programs
Assessment of aqueous graphene as a cancer therapeutics delivery system
No full textGraphene is a nanomaterial used in health and oncology settings. However, several reports have raised the alarm about potential toxicity. This study addressed this concern and determined the in vitro cytotoxicity of few-layer graphene (FLG) flakes produced in bespoke ultrasonic reactors using benign methods. The use of graphene flakes as a potential sensitising agent and a carrier for drug delivery in cancer cells was evaluated. To this end, aqueous based FLG suspensions were systematically characterised using UV-Vis, Raman spectroscopy and High-resolution Transmission electron microscopy (HR-TEM). Cell toxicity characterisation (e.g., cell viability assays using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and cell membrane integrity) of FLG in water were performed together with charge coupled device (CCD) and second harmonic generation (SHG) imaging of live cells in graphene solutions. Collectively, our findings show that NIH 3T3 mouse fibroblast and human fibroblast cells survival was higher than 80% and 90%, respectively upon treatment with the FLG fraction (~ 16 µg/ml) recovered after centrifugation at 2000 revolutions per minute (RPM). In contrast, the cervical cancer cell line HeLa exposed to similar concentrations of FLG flakes resulted in approximately 30% cell death arguing in favour of a sensitising effect in cervical cancer cells
Aligning spectral emissivity profiles to the atmospheric transmission window for radiative cooling using layered dielectrics augmented with metamaterial interfaces
No full textPassive radiative cooling, an innovative approach for cooling buildings and devices, has attracted considerable attention in recent years. One significant challenge in radiative cooling is the need for surfaces with selective spectral emissivity that aligns with the atmospheric transmission of earth. The spectral emissivity of the surface in the 8–13 μm serves as a crucial factor in enhancing the net cooling capacity of the surface. In this study, we achieved a spectral surface emissivity that is aligned with the atmospheric transmission window using layered dielectrics augmented with a metamaterial interface. By harnessing the strong coupling within the gap of a bowtie antenna resulting from the interaction of light with metallic surfaces, we achieve a broadband absorption around a resonance frequency within the atmospheric window spectrum. Additionally, we successfully attained broadband reflection in the visible region with a reflectivity of more than approximately 97 % and in the near-infrared spectra through the design and optimization of alternating layers with high and low refractive indices (SiO2–TiO2) deposited on a thin silver layer. Our results indicate that merging the metamaterial surface with dielectric layers eliminates the need for thick layers in conventional radiative cooling structures. This configuration significantly improves cooling performance, and it results in a more compact and thinner stack
Influence of stacking sequence and compaction force during the AFP process on mechanical performance and damage mechanisms elucidated by acoustic emission insights
No full textThis study examines the effect of consolidation force during Automated Fiber Placement (AFP) on the mechanical and fracture behavior of carbon fiber-reinforced polymer composites with different stacking sequences. Unidirectional (UD), cross-ply (CP), and quasi-isotropic (QI) laminates are fabricated using consolidation forces of 300 N and 600 N. Tensile, mode-I, mode-II, and short beam shear (SBS) tests are conducted, complemented by in-situ acoustic emission (AE) analysis to monitor real-time damage progression. Higher consolidation forces enhance tensile strength, particularly in QI laminates, resulting in a 12% increase, while Young's modulus remains unaffected for UD and CP laminates. Mode-I interlaminar fracture toughness improves by 16% for UD and CP laminates under higher consolidation forces, while QI laminates exhibit minimal change. Mode-II tests reveal that QI laminates demonstrate superior delamination resistance, whereas UD composites show lower toughness due to rapid crack propagation. AE analysis indicates that QI laminates have higher cumulative acoustic counts and energy, reflecting increased damage accumulation and energy dissipation under both mode-I and mode-II loading conditions. Additionally, AE data highlight enhanced interfacial bonding, supported by peak-frequency rates and AE energy levels. This study emphasizes the critical roles of fiber orientation and consolidation force in determining the mechanical performance and damage behavior of AFP-manufactured composites. By integrating in-situ AE techniques, it provides insights into optimizing AFP processes for improved composite performance