Search Results (177)

In this study, theorems and proofs related to spherical and focal curves are presented in the BCV-Sasakian space. An approximate solution to the differential equation characterizing spherical curves in the BCV-Sasakian manifold ${\mathfrak{M}}^3$ is obtained using the Taylor matrix collocation method. The general equations of canal and tubular surfaces are provided within this geometric framework. Additionally, the curvature properties of the tubular surface constructed around a non-vertex focal curve are computed and analyzed. All of these results are presented for the first time in the literature within the context of the BCV-Sasakian geometry. Thus, this study makes a substantial contribution to the differential geometry of contact metric manifolds by extending classical concepts into a more generalized and complex geometric structure. Full article

In this study, we present two novel subclasses of bi-univalent functions defined in the open unit disk, utilizing Liouville–Caputo fractional derivatives. We find constraints on initial Taylor coefficients $|c_2|$, $|c_3|$ for functions in these subclasses of bi-univalent functions. Additionally, by using the values of $a_2,a_3$ we determine the Fekete–Szegö inequality results. Moreover, a few new subclasses are deduced that have not been studied in relation to Liouville–Caputo fractional derivatives so far. The implications of the results are also emphasized. Our results are concrete examples of several earlier discoveries that are not only improved but also expanded upon. Full article

This paper is concerned with the choice of data granularity for the application of the Mack chain ladder model to forecast a loss reserve. It is a sequel to a related paper by Taylor, which considers the same question for the EDF chain ladder model. As in the earlier paper, it considers the question as to whether a decrease in the time unit leads to an increase or decrease in the variance of the loss reserve estimate. The question of whether a Mack chain ladder that is valid for one time unit (here called mesh size) remains so for another is investigated. The conditions under which the model does remain valid are established. There are various ways in which the mesh size of a data triangle may be varied, two of them of particular interest. The paper examines one of these, namely that in which development periods are preserved. Two versions of this are investigated: 1. the aggregation of development periods without change to accident periods; 2. the aggregation of accident periods without change to development periods. Taylor found that, in the case of the Poisson chain ladder, an increase in mesh size always increases the variance of the loss reserve estimate (subject to mild technical conditions). The case of the Mack chain ladder is more nuanced in that an increase in variance is not always guaranteed. Whether or not an increase or decrease occurs depends on the numerical values of certain of the age-to-age factors actually observed. The threshold values of the age-to-age factors at which an increase transitions to a decrease in variance are calculated. In the case of a change in the mesh of development periods, but with no change to accident periods, these values are computed for one particular data set, where it is found that variance always increases. It is conjectured that data sets in which this does not happen would be relatively rare. The situation is somewhat different when changes in mesh size over accident periods are considered. Here, the question of an increase or decrease in variance is more complex, and, in general terms, the occurrence of an increase in variance with increased mesh size is less likely. Full article

Fractional calculus plays a central role in modeling memory-dependent processes and complex dynamics across various fields, including control theory, fluid mechanics, and bioengineering. This study introduces an efficient and stable fractional-order iterative method based on the Caputo derivative for solving nonlinear equations. By employing a Taylor series expansion, a local convergence analysis shows that for $\gamma \in (0,1]$, the method achieves a convergence order of $2\gamma +1$. To address challenges related to memory effects and instability in existing approaches, the proposed scheme incorporates parameter optimization through chaos and bifurcation analysis. Dynamical plane analysis reveals that parameter values within chaotic regimes lead to divergence, while those in stable regions converge uniformly. The method’s performance is evaluated using a set of nonlinear models drawn from biomedical engineering, including enzyme kinetics with inhibition, extended glucose–insulin regulation, drug dose–responses, and lung volume–pressure dynamics. Comparative results demonstrate that the proposed approach outperforms existing methods in terms of iteration count, residual error, CPU time, convergence order, fractal behavior, and memory efficiency. These findings underscore the method’s applicability to complex systems characterized by nonlinearity and memory effects in scientific and engineering contexts. Full article

Given the serious economic burden that citrus diseases impose on fruit farmers and related industries, achieving rapid and accurate disease detection is particularly crucial. In response to the challenges posed by resource-limited platforms and complex backgrounds, this paper designs and proposes a lightweight method for the identification and localization of citrus diseases based on the RT-DETR-r18 model—GYS-RT-DETR. This paper proposes an optimization method for target detection that significantly enhances model performance through multi-dimensional technology integration. First, this paper introduces the following innovations in model structure: (1) A Gather-and-Distribute Mechanism is introduced in the Neck section, which effectively enhances the model’s ability to detect medium to large targets through global feature fusion and high-level information injection.(2) Scale Sequence Feature Fusion (SSFF) is used to optimize the Neck structure to improve the detection performance of the model for small targets in complex environments. (3) The Focaler-ShapeIoU loss function is used to solve the problems of unbalanced training samples and inaccurate positioning. Secondly, the model adopts two model optimization strategies: (1) The Group_taylor local pruning algorithm is used to reduce memory occupation and the number of computing parameters of the model. (2) The feature-logic knowledge distillation framework is proposed and adopted to solve the problem of information loss caused by the structural difference between teachers and students, and to ensure a good detection performance, while realizing the lightweight character of the model. The experimental results show that the GYS-RT-DETR model has a precision of 79.1%, a recall of 77.9%, an F1 score of 78.0%, a model size of 23.0 MB, and an mAP value of 77.8%. Compared to the original model, the precision, recall, the F1 score, the mAP value, and the FPS value have improved by 3.5%, 5.3%, 5.0%, 5.3%, and 10.3 f/s, respectively. Additionally, the memory usage of the GYS-RT-DETR model has decreased by 25.5 MB compared to the original model. The GYS-RT-DETR model proposed in this article can effectively detect various citrus diseases in complex backgrounds, addressing the time-consuming nature of manual detection and improving the accuracy of model detection, thereby providing an effective theoretical basis for the automated detection of citrus diseases. Full article

Background/Objectives: Constraint-induced movement therapy (CIMT) and bimanual training (BIT) have been commonly used to improve upper limb (ULF) in paediatric populations. This study aimed to compare the efficacy of CIMT and BIT for the recovery of ULF in youth with unilateral cerebral palsy (CP) in the immediate, short, and long term. Methods: A systematic review with a meta-analysis of randomised controlled trials (RCTs) from the PubMed/Medline, Scopus, Web of Science, and PEDro databases was conducted. The primary outcomes were the immediate, short-, and long-term effects on ULF, and the secondary outcomes were related to occupational performance and disability. The risk of bias was assessed using the Cochrane RoB 2.0 tool by two researchers independently. Meta-analyses were performed using RevMan 5.3. Results: From the 174 records obtained, 10 RTCs comprising 418 participants were included. Favourable results were observed immediately after intervention for CIMT regarding unimanual ULF using the Quality of Upper Extremity Test (QUEST) (SMD = 1.08; 95% CI = (0.66;1.50)) and Jebsen–Taylor Hand Function Test (JTHFT) (SMD = −0.62; 95% CI = (−1.23;0.00)). These results were maintained in the short term for the QUEST for dissociated movements (SMD = 1.19; 95% CI = (0.40;1.99)) and in the long term for the JTHFT (SMD = −0.38; 95% CI = (−1;0.24)). Conversely, favourable results were obtained immediately after the intervention for BIT regarding bimanual ULF using the Assisting Hand Assessment (SMD = −0.42; 95% CI = (−0.78–0.05)). Conclusions: CIMT could be more effective for improving unimanual ULF and BIT in youth with unilateral CP. The differences between the interventions decreased in the long term. Nevertheless, these findings should be interpreted with caution due to the variability in the intervention programmes. Further research with standardised protocols is needed. Full article

Background: Workplace procrastination is associated with a wide range of negative organizational outcomes. Our objectives are to systematically review the factors of workplace procrastination and the instruments used to measure this construct. Methods: Following PRISMA guidelines, we searched for papers published between 2000 and 2023 through Google Scholar, Science Direct, and Taylor & Francis, using the search terms “workplace procrastination not academic” and “employee procrastination”. Results: After screening, 33 studies were retained for analysis and were also submitted to quality assessment. The factors were grouped into two main categories, i.e., employee-related and external. Several potential factors have been investigated only in a single study, while contradictory findings have been reported regarding the effect of others, especially in culturally diverse samples. Procrastination was measured using ten different instruments, with variations in their conceptual underpinnings. Conclusions: Future advancements in understanding the factors of workplace procrastination would greatly benefit from studies on employee samples from different countries. Moreover, future research should select their workplace procrastination measures based on careful consideration of the specific facets that it aims to investigate. Our findings also suggest that addressing procrastination at work requires a comprehensive approach involving different interventions at both the organizational and individual level. Full article

El Malpais National Monument in New Mexico, USA, is a landscape of significant cultural and geological importance, characterized by extensive lava flows, caves, and cinder cones. Despite its harsh terrain, El Malpais holds deep cultural and spiritual meanings for Native American communities, including the Acoma, Zuni, Laguna, and Navajo tribes, whose cosmologies and histories are interwoven with this landscape. Employing a mixed-methods approach combining ethnographic fieldwork with comparative literature studies, this paper documents how these Indigenous groups perceive and interpret interconnected geological features as sacred and meaningful parts of their ancestral heritage. The findings reveal that volcanic landscapes are central not only to cultural origin narratives but also to ongoing rituals, resource use, and pilgrimage practices. This interconnectedness is exemplified by the cultural links between El Malpais and adjacent Mount Taylor, highlighting how geological features form a unified sacred geography. This study positions El Malpais as a culturally animated landscape, where Indigenous epistemologies and spiritual relationships with volcanic landforms challenge conventional notions of geoheritage and call for relational, community-informed approaches to heritage management. Full article

A pioneering detailed comparative study of the dynamics of plasma flows generated by high-power nanosecond and high-intensity femtosecond laser pulses with similar fluences of up to $3\times {10}^4$ J/cm² is presented. The experiments were conducted on the petawatt laser facility PEARL using two types of high-power laser radiation: femtosecond pulses with energy exceeding 10 J and a duration less than 60 fs, and nanosecond pulses with energy exceeding 10 J and a duration on the order of 1 ns. In the experiments, high-velocity (>100 km/s) flows of «femtosecond» (created by femtosecond laser pulses) and «nanosecond» plasmas propagated in a vacuum across a uniform magnetic field with a strength over 14 T. A significant difference in the dynamics of «femtosecond» and «nanosecond» plasma flows was observed: (i) The «femtosecond» plasma initially propagated in a vacuum (no B-field) as a collimated flow, while the «nanosecond» flow diverged. (ii) The «nanosecond» plasma interacting with external magnetic field formed a quasi-spherical cavity with Rayleigh–Taylor instability flutes. In the case of «femtosecond» plasma, such flutes were not observed, and the flow was immediately redirected into a narrow plasma sheet (or «tongue») propagating across the magnetic field at an approximately constant velocity. (iii) Elongated «nanosecond» and «femtosecond» plasma slabs interacting with a transverse magnetic field broke up into Rayleigh–Taylor «tongues». (iv) The ends of these «tongues» in the femtosecond case twisted into vortex structures aligned with the ion motion in the external magnetic field, whereas the «tongues» in the nanosecond case were randomly oriented. It was suggested that the twisting of femtosecond «tongues» is related to Hall effects. The experimental results are complemented by and consistent with numerical 3D magnetohydrodynamic simulations. The potential applications of these findings for astrophysical objects, such as short bursts in active galactic nuclei, are discussed. Full article

Artificial intelligence (AI) is revolutionizing the fashion, textile, and clothing industries by enabling automated assessment of garment quality, condition, and recyclability, addressing key challenges in sustainability. This systematic review explores the applications of AI in evaluating clothing quality and condition within the framework of a circular economy, with a focus on supporting second-hand clothing resale, charitable donations by NGOs, and sustainable recycling practices. A total of 135 research resources were identified through searching academic databases including Google Scholar, Springer, ScienceDirect, IEEE, Taylor and Francis, and Sage journals. These publications were subsequently refined down to 49 based on selected inclusion criteria. The selection of these sources from diverse databases was undertaken to mitigate any potential bias in the selection process. By analyzing the effectiveness and challenges of related peer-reviewed articles, conference papers, and technical reports, this study highlights state-of-the-art methodologies such as convolutional neural networks (CNNs), hybrid models, and other machine vision systems. A critical aspect of this review is the examination and analysis of datasets used for model development, categorized and detailed in a comprehensive table to guide future research. Whilst the findings emphasize the potential of AI to enhance quality assurance in second-hand clothing markets, streamline textile sorting for donations and recycling, and reduce waste in the fashion industry, they also highlight gaps in the available datasets, often due to limited size and scope. The types of textiles captured were most commonly swatches of fabric, with 20 studies examining these, whereas whole garments were less frequently studied, with only 7 instances. This review concludes with insights into future research directions and the promising use of AI within fashion and textiles to facilitate a transition to a circular economy. This project was supported through RMIT University’s School of Fashion and Textiles internal seed funding (2024). Full article

For the management of the water cycle, it is essential to comprehend evapotranspiration (ET) and how it changes over time and space, especially in relation to vegetation. Here, using the Priestley–Taylor Jet Propulsion Laboratory (PT-JPL) model, we explored the spatiotemporal variations in ET across different time scales during 1982–2018 in the Wuding River Basin. We also quantitatively evaluated the driving mechanisms of climate and vegetation changes on ET changes. Results showed that the ET estimate by the PT-JPL model showed good agreement (R² = 0.71–0.84) with four ET products (PML, MOD16A2, GLASS, FLDAS). Overall, the ET increased significantly at a rate of 3.11 mm/year (p < 0.01). Spatially, ET in the WRB is higher in the southeast and lower in the northwest. Attribution analysis indicated that vegetation restoration (leaf area index) was the dominant driver of ET changes (99.93% basin area, p < 0.05), exhibiting both direct effects and indirect mediation through the Vapor Pressure Deficit. Temperature influences emerged predominantly through vegetation feedbacks rather than direct climatic forcing. These findings establish vegetation restoration as a key driver of regional ET, providing empirical support for optimizing revegetation strategies in semi-arid environments. Full article

The instability of a non-Newtonian dielectric fluid jet of power-law (P-L) type injected when streaming dielectric gas through porous media is examined using electrohydrodynamic (EHD) linear analysis. The interfacial boundary conditions (BCs) are used to derive the dispersion relation for both shear-thinning (s-thin) and shear-thickening (s-thick) fluids. A detailed discussion is outlined on the impact of dimensionless flow parameters. The findings show that jet breakup can be categorized into two instability modes: Rayleigh (RM) and Taylor (TM), respectively. For both fluids, the system in TM is found to be more unstable than that found in RM, and, for s-thick fluids, it is more unstable. For all P-L index values, the system is more unstable if a porous material exists than when it does not. It is demonstrated that the generalized Reynolds number (${Re}_n$), Reynolds number ($Re$), P-L index, dielectric constants, gas-to-liquid density, and viscosity ratios have destabilizing influences; moreover, the Weber number ($We$), electric field (EF), porosity, and permeability of the porous medium have a stabilizing impact. Depending on whether its value is less or more than one, the velocity ratio plays two different roles in stability, and the breakup length and size of P-L fluids are connected to the maximal growth level and the instability range in both modes. Full article

A common challenge in direct digital frequency synthesizers (DDFSs) is obtaining high memory compression while maintaining good output signal purity. To address this challenge, in this paper, we present a 16-bit, quadrature direct digital frequency synthesizer (DDFS) that utilizes the second-order Taylor series polynomial interpolation in the phase-to-amplitude conversion. In this approach, the sinusoidal signal is divided into multiple segments, and for each segment, related values are stored into a look-up table (LUT). The amplitude values for each segment are calculated using the stored LUT values and the second-order Taylor series polynomial interpolation. A Python-based model was created to optimize the number of segments, and the resulting design was coded using register-transfer level VHDL. The design is synthesized and implemented on an AMD Artix 7 FPGA, and the implementation results are presented. We show that the proposed design is capable of reaching a very high memory compression ratio of 5178:1. Additionally, the design generates both sine and cosine with high spectral purity utilizing a low number of FPGA resources compared to previous work. With 107 logic slices and 3 DSP slices, the design reaches a spurious-free dynamic range (SFDR) of −102.9 dBc. Full article

The aim of this study is to examine the behavior of subharmonics in a one-dimensional cavity filled with a bubbly liquid, leveraging the nonlinear softening phenomenon of the medium at high amplitudes to enhance subharmonic generation. To this purpose, we use a numerical model developed previously that solves a coupled differential system formed by the wave equation and a Taylor-expanded Rayleigh–Plesset equation. This system describes the nonlinear mutual interaction between ultrasound and bubble vibrations. We carry out several different simulations to measure the response of the subharmonic component $f/2$ and the acoustic source frequency signal f when the cavity is excited over a range around the linear resonance frequency of the cavity (the resonance value obtained at low pressure amplitudes). Different source amplitudes in three different kinds of medium are used. Our results reveal several new characteristics of subharmonics as follows: their generation is predominant compared to the source frequency; their generation is affected by the softening of the bubbly medium when acoustic pressure amplitudes are raised; this specific behavior is solely an acoustically-related phenomenon; their behavior may indicate that the bubbly liquid medium is undergoing a softening process. Full article

Communication, collaboration, critical thinking, and creativity are core 21st century skills. Meanwhile, educational robotics is regarded as a contributor to their promotion. Hence, education tries to embrace them in school curricula. Yet, there is a lack of reviews in the existing literature presenting the robotics activities used to promote children’s communication, collaboration, creativity, and critical thinking from an early age. Consequently, this study employed a thematic literature review aiming to 1. map the research field of robotics activities suitable for promoting kindergarteners’ skills, 2. facilitate researchers and teachers in their current and future work related to robotics, and 3. provide guidelines and a model flow related to robotics activities for supporting educators in integrating them into their school reality. The PRISMA Flow Diagram and the Atlas.ti software were used to investigate the Scopus database and the Taylor and Francis register. Finally, 16 papers were examined out of 349 initially retrieved and published from 2014 to 2025. Based on our findings, a few interventions have been aimed at fostering kindergarteners’ communication, collaboration, creativity, and critical thinking via educational robotics, but there is rarely a clear record of robotics activities achieving that. Moreover, there is no specific model or guideline for developing such activities in kindergarten. Full article