Search Results (989)

A parallel implementation of wavelet-based autofocus (WBA) was presented to accelerate recursive operations and reduce computational costs. WBA evaluates digital focus indices (DFIs) using first- or second-order moments of the wavelet coefficients in high-frequency subbands. WBA is generally accurate and reliable; however, its computational cost is high owing to biorthogonal decomposition. Thus, this study parallelized the Daubechies-6 wavelet and norms of the high-frequency subbands for the DFI. The kernels of the DFI computation were constructed using open sources for driving multicore processors (MCPs) and general processing units (GPUs). The standard C++, OpenCV, OpenMP, OpenCL, and CUDA open-source platforms were selected to construct the DFI kernels, considering hardware compatibility. The experiment was conducted using the MCP, peripheral GPUs, and CPU-resident GPUs on desktops for advanced users and compact devices for industrial applications. The results demonstrated that the GPUs provided sufficient performance to achieve WBA even when using budget GPUs, indicating that the GPUs are advantageous for practical applications of WBA. This study also implies that although budget GPUs are left unused, they can potentially be great resources for wavelet-based processing. Full article

The relationship between the seismic regime and humidity, pressure, temperature, and wind speed measured at a network of stations on the Japanese islands was studied for the period from 1973 to 2025. For each of the parameters, weighted average time series were constructed using the principal component method and then subjected to wavelet decomposition. For wavelet decomposition levels, the amplitudes of the envelopes and the points of their local extrema were found and compared with the times at which earthquakes occurred. The problem of estimating an advanced measure of envelope extremum points relative to earthquake moments was considered using a model of interacting point processes. For a sequence of 213 strong earthquakes with a magnitude of at least 6.5, the same numbers for the largest local maxima and the smallest local minima were selected for the extrema of the envelope amplitude of each parameter. It turned out that the largest advance measures occurred for the seventh level of decomposition (the period from 16 to 32 days). Two advance mechanisms were identified: one mechanism is associated with the trigger effect of cyclones on seismicity, and the second is associated with the occurrence of atmospheric earthquake precursors. Full article

We consider a class of strongly mixing sequences with infinite second moment. This class contains important GARCH processes that are applied in econometrics. We show the relative stability for such processes and construct a counterexample. We apply these results and obtain a new CLT without the requirement of exponential decay of mixing coefficients, and provide a counterexample to this as well. Full article

The current engineering structural design code employs a direct probability design method based on the Taylor series expansion of the performance function at verification points, retaining only linear terms. This approach ignores the curvature and other nonlinear properties of the performance function, leading to insufficient accuracy. To address the deficiencies of the current design method, this paper develops an approximate probability design method that considers the curvature of the limit state surface, integrating it with the second-order moment theory based on the direct probability design method. Using a simply supported plate as a representative example, this paper systematically compares the performance of the proposed design method with the direct probability design method, the partial coefficient method, and the design value method in reinforcement design. The reinforcement areas calculated by the four methods are similar, confirming the correctness and practicality of the proposed method for engineering applications. The accuracy of the design outcomes from the various methods is validated through Monte Carlo simulation. The results indicate that the method proposed in this paper exhibits a high accuracy, with the relative errors of the reliability indices in the two examples being 0.346% and 0.228%, respectively—significantly lower than those of the direct probability design method (2.919% and 0.769%, respectively). This underscores the effectiveness and substantial benefits of the proposed method in structural reliability design, offering a dependable, highly accurate, and economically viable design tool for engineering applications. Full article

Survival analysis is a fundamental tool for modeling time-to-event data in healthcare, engineering, and finance, where censored observations pose significant challenges. While traditional methods like the Beran estimator offer nonparametric solutions, they often struggle with the complex data structures and heavy censoring. This paper introduces three novel survival models, iSurvM (imprecise Survival model based on Mean likelihood functions), iSurvQ (imprecise Survival model based on Quantiles of likelihood functions), and iSurvJ (imprecise Survival model based on Joint learning), that combine imprecise probability theory with attention mechanisms to handle censored data without parametric assumptions. The first idea behind the models is to represent censored observations by interval-valued probability distributions for each instance over time intervals between event moments. The second idea is to employ the kernel-based Nadaraya–Watson regression with trainable attention weights for computing the imprecise probability distribution over time intervals for the entire dataset. The third idea is to consider three decision strategies for training, which correspond to the proposed three models. Experiments on synthetic and real datasets demonstrate that the proposed models, especially iSurvJ, consistently outperform the Beran estimator from accuracy and computational complexity points of view. Codes implementing the proposed models are publicly available. Full article

Cloud detection is an indispensable step in satellite remote sensing of cloud properties and objects under the influence of cloud occlusion. Nevertheless, interfering targets such as snow and haze pollution are easily misjudged as clouds for most of the current algorithms. Hence, a robust cloud detection algorithm is urgently needed, especially for regions with high latitudes or severe air pollution. This paper demonstrated that the passive satellite detector Advanced Geosynchronous Radiation Imager (AGRI) onboard the FY-4A satellite has a great possibility to misjudge the dense aerosols in haze pollution as clouds during the daytime, and constructed an algorithm based on the spectral information of the AGRI’s 14 bands with a concise and high-speed calculation. This study adjusted the previously proposed cloud mask rectification algorithm of Moderate-Resolution Imaging Spectroradiometer (MODIS), rectified the MODIS cloud detection result, and used it as the accurate cloud mask data. The algorithm was constructed based on adjusted Fisher discrimination analysis (AFDA) and spectral spatial variability (SSV) methods over four different underlying surfaces (land, desert, snow, and water) and two seasons (summer and winter). This algorithm divides the identification into two steps to screen the confident cloud clusters and broken clouds, which are not easy to recognize, respectively. In the first step, channels with obvious differences in cloudy and cloud-free areas were selected, and AFDA was utilized to build a weighted sum formula across the normalized spectral data of the selected bands. This step transforms the traditional dynamic-threshold test on multiple bands into a simple test of the calculated summation value. In the second step, SSV was used to capture the broken clouds by calculating the standard deviation (STD) of spectra in every 3 × 3-pixel window to quantify the spectral homogeneity within a small scale. To assess the algorithm’s spatial and temporal generalizability, two evaluations were conducted: one examining four key regions and another assessing three different moments on a certain day in East China. The results showed that the algorithm has an excellent accuracy across four different underlying surfaces, insusceptible to the main interferences such as haze and snow, and shows a strong detection capability for broken clouds. This algorithm enables widespread application to different regions and times of day, with a low calculation complexity, indicating that a new method satisfying the requirements of fast and robust cloud detection can be achieved. Full article

Despite increased interest in embodied learning, the role of sensorimotor activity in shaping students’ probabilistic reasoning remains underexplored. This design-based study examines how high school students develop key probabilistic concepts, including sample space, certainty, and event probability, through whole-body movement activities situated in an authentic classroom setting. Grounded in embodied cognition theory, we introduce a two-axis interpretive framework. One axis spans sensorimotor exploration and formal reasoning, drawing from established continuums in the literature. The second axis, derived inductively from our analysis, contrasts engagement with distraction, foregrounding the affective and attentional dimensions of embodied participation. Students engaged in structured yet open-ended movement sequences that elicited intuitive insights. This approach, epitomized by one student’s spontaneous question, “Can I use my leg too?”, captures the agentive and improvisational character of the embodied learning environment. Through five analyzed classroom episodes, we trace how students shifted between bodily exploration and formalization, often through nonlinear trajectories shaped by play, uncertainty, and emotionally driven reflection. While moments of insight emerged organically, they were also fragile, as they were affected by ambiguity and the difficulty in translating physical actions into mathematical language. Our findings underscore the pedagogical potential of embodied design for probabilistic learning while also highlighting the need for responsive teaching that balances structure with improvisation and supports affective integration throughout the learning process. Full article

The lodging resistance of rice is a prerequisite for ensuring yield and rice quality. An in-depth analysis of key traits affecting rice lodging resistance is crucial for guiding the cultivation of excellent rice varieties and field production. Given consumer demand for high-quality rice and frequent extreme weather conditions, this study focused on six high-quality conventional rice varieties and compared the main stem internode physical traits, stem and sheath plumpness traits, main stem mechanical properties, yield-related traits, and panicle characteristics of the plants based on field phenotype measurements. Among them, three varieties showed lodging resistance in the field, while the other three varieties all experienced varying degrees of lodging susceptibility. The results showed that lodging-resistant varieties exhibited a more reasonable internode structure, lower plant height, gravity center height, and relative gravity center height, as well as shorter and thicker second internodes (N2). Additionally, they had higher sheath phimosis degree, greater bending stress, internode-breaking moment, and plant-breaking moment, along with a lower lodging index compared to lodging-susceptible varieties. Specifically, lodging-resistant varieties had 0.83–9.61% lower plant height, 4.11–16.10% lower gravity center height, and 0.09–12.68% lower relative gravity center height than those of lodging-susceptible varieties. Their N2 internode length was 8.96–44.69% shorter, while stem and sheath weight ratios were 16.37–268.58% and 8.27–165.01% higher than those of lodging-susceptible varieties, respectively. At the same time, lodging-resistant varieties exhibit the ability to stabilize yield while reducing their own risk of lodging by increasing effective panicles and reducing single panicle weight. In addition, NX42, LD3, and SY17 were ultimately evaluated as low-risk lodging varieties in this study. This study aims to address the lodging problem of high-quality conventional rice and analyze the key mechanisms underlying its lodging resistance. The research provides important theoretical support for genetic improvement of high-quality conventional rice. Full article

This work presents a new insight into the buckling phenomenon to approach the calculation of the compressed bar with the following firm supports: bi-pinned, bi-fixed, and fixed-pinned. Buckling is redefined as the result of second-order deformations in the real bar by gradually applying the compression load, thus dismissing Euler’s critical load. The analytical results are obtained from the differential equation of the directrix beam with sinusoidal deformation associated with each type of support. The bending moment is generated only by the compression load acting on the initial geometric imperfection. These analytical solutions are associated with first-order effects, applying the entire compressive load, and with second-order effects, applying the load gradually. The analytical solutions are continuous functions. In this paper, the Finite Transfer Method was applied to obtain numerical results. The bending moments, transverse displacements, and normal stresses are presented as the results. Beams with different initial imperfections in the directrix are studied: with sinusoidal deformation, with deformation produced by a specific transverse load, and with deformation produced by a uniform transverse load. The results obtained through the analytical expressions derived from the gradual application of the load are compared with those results obtained numerically when calculating the beam under second-order conditions. It is concluded that in structural practice, they are equivalent. Full article

This paper investigates the pth moment exponential stability of random impulsive delayed nonlinear systems (RIDNS) with multiple periodic delayed impulses. Moreover, the continuous dynamics are described by random delay differential equations whose random disturbances are driven by second-order moment processes. Using the periodic impulsive intensity (PII), average delay time (ADT), average impulsive delay (AID), as well as the Lyapunov method, we present some pth exponential stability criteria for impulsive random delayed nonlinear systems with multiple delayed impulses. Furthermore, the criterion is unified, which is not only applicable to stable or unstable original systems but also takes into account the coexistence of stabilizing and destabilizing impulses. The periodic structure of impulses and their intensities introduces an intrinsic temporal symmetry, which plays a critical role in determining the stability behavior of the system. This symmetry-based perspective highlights the fundamental impact of regularly recurring impulsive actions on system dynamics. Several illustrated examples are given to verify the effectiveness of our results. Full article

In this paper, we study a generalized Duffin–Kemmer equation for a spin-1 particle with two characteristics, anomalous magnetic moment and polarizability in the presence of external uniform magnetic and electric fields. After separating the variables, we obtained a system of 10 first-order partial differential equations for 10 functions $f_A(r,z)$. To resolve this complicated problem, we first took into account existing symmetry in the structure of the derived system. The main step consisted of applying a special method for fixing the r-dependence of ten functions $f_A(r,z),A=1,\dots ,10$. We used the approach of Fedorov–Gronskiy, according to which the complete 10-component wave function is decomposed into the sum of three projective constituents. The dependence of each component on the polar coordinate r is determined by only one corresponding function, $F_i\left(r\right),i=1,2,3$. These three basic functions are constructed in terms of confluent hypergeometric functions, and in this process a quantization rule arises due to the presence of a magnetic field.In fact, this approach is a step-by-step algebraization of the systems of equations in partial derivatives. After that, we derived a system of 10 ordinary differential equations for 10 functions $f_A\left(z\right)$. This system was solved using the elimination method and with the help of special linear combinined with the involved functions. As a result, we found three separated second-order differential equations, and their solutions were constructed in the terms of the confluent hypergeometric functions. Thus, in this paper, the three types of solutions for a vector particle with two additional electromagnetic characteristics in the presence of both external uniform magnetic and electric fields. Full article

Online psychotherapy for patients with suicidal behavior was considered inappropriate by the Brazilian Federal Psychology Council prior to the COVID-19 pandemic. Due to the need for physical distancing, this restriction was temporarily suspended. This study aims to analyze the perceptions of Brazilian clinical psychologists regarding online psychotherapy for patients with suicidal behavior in the context of the COVID-19 pandemic, to generate a theoretical understanding of this experience. It is a qualitative, exploratory, longitudinal study based on the Constructivist Grounded Theory framework. Ten clinical psychologists who conducted online psychotherapy for patients with suicidal behavior during the pandemic were interviewed at two moments, with an interval of approximately two years: the first round was conducted from December 2020 to March 2021, followed by a second round between November and December 2022. Data analysis led to four categories: (1) Reflecting on suicidal behavior; (2) Addressing specificities of online interventions; (3) Managing suicidal behavior in online psychotherapy; (4) Evaluating online psychotherapy for patients with suicidal behavior. The theoretical model “Pathways of care: main roads and access routes in online psychotherapy for suicidal behavior” was constructed. It was concluded that online psychotherapy for patients with suicidal behavior is complex and requires caution but is feasible and can be important in specific circumstances. This makes it an additional resource for suicide prevention and mental health promotion. Full article

This study presents the design, implementation, and experimental validation of a self-contained earthquake early warning system (EEWS) based on real-time frequency-domain analysis of ground motion. The proposed system integrates a low-noise triaxial micro-electro-mechanical system (MEMS) accelerometer with a high-performance microcontroller, enabling autonomous seismic event detection without dependence on external communications or centralized infrastructure. The characteristic period of ground motion (τ_c) is estimated using a spectral moment method applied to the first three seconds of vertical acceleration following P-wave arrival. Event triggering is based on a short-term average/long-term average (STA/LTA) algorithm, with alarm logic incorporating both spectral and amplitude thresholds to reduce false positives from low-intensity or distant events. Experimental validation was conducted using a custom-built uniaxial shaking table, replaying 10 real earthquake records (Mw 4.1–7.7) in 20 repeated trials each. Results show high repeatability in τ_c estimation and strong correlation with event magnitude, demonstrating the system’s reliability. The findings confirm that modern embedded platforms can deliver rapid, robust, and cost-effective seismic warning capabilities. The proposed EEW solution is well-suited for deployment in critical infrastructure and resource-limited seismic regions, supporting scalable and decentralized early warning applications. Full article

This study proposes a parallel model reduction method for two-dimensional discrete-time systems, utilizing Krawtchouk moments and equivalent transformation. This work makes two significant contributions. First, we introduce a projection subspace that is independent of the input as well as of the Krawtchouk parameters, thus ensuring robustness. Second, we propose an efficient parallel algorithm for computing the basis of the projection subspace. With the difference relation of Krawtchouk polynomials and the analytic identity theorem, we obtain the explicit formula for the Krawtchouk moments of the state, which is input-dependent and Krawtchouk-parameter-dependent. We derive a projection subspace that is independent of both input and Krawtchouk parameter, such that it is equivalent to the subspace spanned by the Krawtchouk moments. Further, we propose a parallel strategy based on the equivalent transformation of the block bi-diagonal Toeplitz matrices with bi-diagonal blocks to compute the basis of the projection subspace, facilitating acceleration of the model reduction process on high-performance computers. Moreover, we analyze the Krawtchouk moment invariants of the proposed parallel method. Finally, the effectiveness of the proposed method is illustrated by two numerical examples. Full article

Background/Objectives: Interstitial lung disease (ILD) is a frequent complication of rheumatoid arthritis (RA), representing the most common extra-articular manifestation (with a prevalence of about 10–60%) and the second cause of mortality. Spondyloarthritides (SpAs) are chronic arthritides that share with RA both a similar disease burden and similar therapeutical approaches. The evaluation of ILD is challenging, given the low sensitivity of X-ray and pulmonary function tests, and the radiation exposure linked to repetitive HRCT. Lung ultrasound (LUS) has shown potential in the evaluation of ILD in autoimmune diseases. The purpose of this study is to assess the prevalence of ILD in a cohort of SpA patients (pts) using LUS in comparison with healthy subjects (HSs). The secondary aim is to evaluate potential correlations between ILD and clinical features within the SpA cohort using LUS. Methods: Consecutive SpA out-patients were examined by LUS, applying the definition for pleural line irregularity (PLI) recently provided by the OMERACT taskforce for LUS in systemic sclerosis. Seventy-one intercostal spaces were studied (14 in the anterior chest, 27 lateral and 30 posterior) in all the pts/HS using an Esaote MyLab25 Gold US machine with a linear 7.5–10 MHz probe. A total pleural score was calculated. Each patient answered to Italian-validated PROs on respiratory function (Leicester and Saint-George), global health (SF-36) and dyspnea (mMRC scale). Clinical data on disease duration, disease onset, disease activity (at the moment of the examination) and methotrexate (MTX) or biologics treatment were collected from the medical records. Results: Seventy-three SpA pts (46 psoriatic arthritis -PsA- and 27 ankylosing spondylitis -AS-) and 56 HS were studied. No significant differences were demonstrated between groups (SpA vs. HS and PsA vs. AS) for age, sex, BMI and smoking habits. The total PLI score was significantly higher in SpA pts than in HS (p < 0.001). A positive correlation was found between the total PLI score and the PLI score from anterior, posterior and lateral chest. The posterior region of the chest showed a higher PLI score than the anterior and lateral regions. No statistically significant differences were found between PsA and AS. MTX use was not a risk factor for PLI (no differences were found between SpA MTX+ and SpA MTX- patients). PROs (Leicester, Saint-George and SF-36) were not related to the PLI total score. A significant correlation was found only between the SF36 score and the presence of PLI in the anterior chest. PROs were instead correlated with each other, showing a good concordance for absence/presence of symptoms. Disease activity, disease duration and age at disease-onset were not related to PLI total score. Smoking habit was found to be predictive of a significantly higher PLI score both in SpA patients and HSs. Conclusions: LUS examination shows a higher amount of PLI in SpA patients with respect to HSs. Smoking habit was the only clinical feature correlated to PLI on LUS examination in our population. Full article