Weighted Research Articles

State estimation of magnetorheological suspension of all-terrain vehicle based on a novel adaptive Sage–Husa Kalman filtering

Abstract For the magnetorheological (MR) suspension control system of all-terrain vehicles (ATVs), state estimation is an effective method to obtain system feedback signals that cannot be directly measured by sensors. However, when confronted with modeling errors and sudden changes in sensor noise during complex road driving, conventional estimation methods with fixed parameters encounter challenges in accurately estimating the states of ATV suspension system. To address this issue, this paper introduces a novel adaptive Sage-Husa Kalman filter (ASHKF) algorithm to estimate the sprung and unsprung velocity of ATV suspension system. The algorithm uses exponential weighting function and gradient detection function to adaptively adjust the attenuation coefficient according to the driving conditions of the ATV, thereby realizing real-time correction of the covariance matrix of the prediction error. Ultimately, through simulation and real-vehicle testing, it is demonstrated that the designed ASHKF is able to effectively improve the state estimation accuracy of the speed signal of the suspension system under off-road driving conditions with low-frequency noise and outlying disturbances, and the accuracy is improved by 62.70% compared with that of the conventional Sage-Husa Kalman filter (SHKF).

Hyperbolic valued Beurling weighted bicomplex Lebesgue spaces and some of their geometric characteristics

This study introduces hyperbolic-valued Beurling weight functions and establishes bicomplex weighted Lebesgue spaces using these weight functions. Further, it examines several geometric properties of spaces, such as BC-convexity, BC-strict convexity, and BC-uniform convexity.

Hypothalamic deep brain stimulation augments walking after spinal cord injury.

A spinal cord injury (SCI) disrupts the neuronal projections from the brain to the region of the spinal cord that produces walking, leading to various degrees of paralysis. Here, we aimed to identify brain regions that steer the recovery of walking after incomplete SCI and that could be targeted to augment this recovery. To uncover these regions, we constructed a space-time brain-wide atlas of transcriptionally active and spinal cord-projecting neurons underlying the recovery of walking after incomplete SCI. Unexpectedly, interrogation of this atlas nominated the lateral hypothalamus (LH). We demonstrate that glutamatergic neurons located in the LH (LHVglut2) contribute to the recovery of walking after incomplete SCI and that augmenting their activity improves walking. We translated this discovery into a deep brain stimulation therapy of the LH (DBSLH) that immediately augmented walking in mice and rats with SCI and durably increased recovery through the reorganization of residual lumbar-terminating projections from brainstem neurons. A pilot clinical study showed that DBSLH immediately improved walking in two participants with incomplete SCI and, in conjunction with rehabilitation, mediated functional recovery that persisted when DBSLH was turned off. There were no serious adverse events related to DBSLH. These results highlight the potential of targeting specific brain regions to maximize the engagement of spinal cord-projecting neurons in the recovery of neurological functions after SCI. Further trials must establish the safety and efficacy profile of DBSLH, including potential changes in body weight, psychological status, hormonal profiles and autonomic functions.

The proposal and calculation method of the annular domain weight function for the electromagnetic flowmeter under annular conductivity distribution

Researching on the characteristic of weight function distribution under non-uniform conductivity distribution is of significant importance for expanding the engineering applications of electromagnetic flowmeter. In this paper, the characteristic of weight function distribution is firstly explored for annular conductivity distribution where the center and outer ring are both conductive. The research results indicate an important finding that the average value of the weight function within any small annular domain of the center or outer ring remains constant as the radial position changes. Therefore, the concept of ‘annular domain weight function’ is then innovatively proposed. Furthermore, the relationship is studied between the ratio of the annular domain weight function of the center and outer ring and the annular feature parameters. Ultimately, the correlations are obtained for calculating the annular domain weight functions of the center and outer ring.

Weight functions for [formula omitted]-stresses in inner/outer double edge cracked circular rings

Weight functions (WF) for calculating the elastic T-stresses for inner edge cracked and outer edge cracked ring specimens are derived in this paper. Six forms of WF are considered, each of which requires only two reference T-stress solutions obtained using finite element method (FEM). Uniform and linear crack-face pressures are chosen as the two reference loading configurations. Quadratic and cubic crack-face pressures are chosen to validate the T-stresses obtained from WF, for both the ring specimens. When compared to T-stresses obtained from FEM, a percentage error of less than 3% is obtained for both the specimens, and hence the derived WF can be used for determining the T-stress solutions for any loading configurations. The derived WF is then used to determine the T-stresses in inner edge cracked and outer edge cracked circular rings subjected to uniform diametrical compression over arcs of the outer boundary. The effect of load distribution angle on the T-stresses is also found for the two rings for various inner to outer radii ratios.

Weight function and stress intensity factors for external circumferential surface cracks with high aspect ratio in cylinders

Weight function and stress intensity factors for external circumferential surface cracks with high aspect ratio in cylinders

A study of blind denoising algorithms for two-scale real images based on partial differential equations

In order to better preserve the details and texture information in the image, a dual scale real image blind denoising algorithm based on partial differential equations is studied. Input real image information, perform small-scale denoising based on differential curvature partial differential equations, and combine with a new diffusion coefficient function to distinguish the edges, flat areas, and noise of the image, allowing the algorithm to retain more subtle information such as weak edges and textures while removing noise. For the large-scale information in the input real image, a multi-stage partial differential equation is used for denoising processing. Based on the mixed denoising method of 8-neighborhood and implicit curvature, a weight function is constructed to control the proportion of the two types of equations in image denoising, effectively achieving the goal of large-scale image denoising. The experimental results show that in the MATLAB coding platform, this algorithm can eliminate different types of noise, preserve more edge and detail information of the image, and improve the registration and recognition accuracy in the image application process.

Effects of Laurus extract against cadmium-induced neurotoxicity in rats

Cadmium (Cd) is a hazardous heavy metal with widespread environmental presence, posing significant threats to human and animal health. This study investigates the neurotoxic effects of Cd exposure and explores the therapeutic efficacy of Laurus nobilis L. in counteracting these adverse effects. Cd exposure induces oxidative stress and neurotoxicity, leading to neuronal damage and histopathological alterations. Laurus, known for its antioxidant properties, is assessed for its potential in mitigating Cd-induced neurotoxicity through in vitro antioxidant assays, GC–MS analysis, HPLC profiling, and experimental animal models. Results demonstrate that Laurus ethanolic extract exhibits significant antioxidant activity, attributed to its phenolic and flavonoid constituents. GC–MS analysis reveals various bioactive compounds in the extract, including Hexadecanoic acid methyl ester and (Z)-13-Docosenamide, which posses neuroprotective properties. HPLC analysis identifies phenolic compounds such as ellagic acid and flavonoids like rutin and kaempferol in the extract. In vivo studies in rats exposed to Cd demonstrate that Laurus extract administration mitigates Cd-induced alterations in body and brain weight, hematological parameters, liver and kidney function, oxidative stress markers, and acetylcholinesterase (AchE) activity. Histopathological examination confirms the protective effects of Laurus against Cd-induced neuronal damage. The SOD model, validated with high resolution (2.05 Å) and strong R values (work: 0.192, free: 0.236, observed: 0.194), shows strong structural stability (C-score: 0.30). Docking studies reveal high binding affinities of kaempferol (−8.1 kcal/mol) and rutin (−8.7 kcal/mol) with SOD with kaempferol demonstrating superior solubility, lipophilicity, and drug-likenessSimulation analysis confirms the protein’s flexibility and adaptability, highlighting its therapeutic potential, especially with kaempferol. These findings suggest the therapeutic potential of Laurus. as a natural remedy for Cd-induced neurotoxicity, highlighting its antioxidant and neuroprotective properties.

Metallic Bipolar Plates for Polymer Electrolyte Fuel Cell (PEFC) Used in Electric Vehicles using the WSM Method

Metallic Bipolar Plates for Polymer Electrolyte Fuel Cell (PEFC) used in electric vehicles. Electric vehicles use electrolytic polymeric fuel cells (PEFCs) built of bipolar sheet metal. Along with the MEA, One of the most essential components of a PEFC cell is the bipolar plate. since they support the MEA, provide rigidi-ty to the layer, and even allow for gas diffusion. Electrical conductivity is provided by the entire electrode surface. The control of heat and the ejection of product water are two additional benefits of a well-prepared bipolar plate [103-105]. In the PEFC stack, bipolar plates are placed between the MEAs so that each of them offers a link to one end of a MEA and, on the other side, to the cath of an adjacent MEA. Bi-polar panels should be small and thin to reduce For PEMFCs, a variety of metal bipolar plates are now being investigated to suit the demands of lowering costs, increasing stacking size, lowering weight, and raising energy density. The quality of interest strategy was compared to the best answer (TOPSIS) the multi-attribute decision-making approach (MADM) in this work, the optimal substance for a metallic bi-polar plate is selected using (MADM). For electrolyte polymer fuel cells (PEFCs), which can have numer-ous competing objectives? Material designers can choose the best material based on preset criteria with the use of a suggested algorithm tool. The theoretical framework is followed by a case study on the mate-rial selection for a PEFC bipolar plate. A list of all the products that meet the requirements for selection, including production costs, by dividing each of our objectives by a user-supplied weight, we divide our audience into a single goal via the weighted sum approach. One of the most popular methods is this one. When considering overall weights, one concern is determining how much weight to give each goal. The primary goal governs are added with varying weights in the weighed total approach, and the sum is then optimized. The goal that function is optimized while another is constrained to a variable's value in the electrically operated constraint approach you can generate an integrated analysis by combining several inputs and weights using the Total Weight function. In that several raster inputs representing various fac-tors can be easily mixed, mixing weights or relative importance, it is comparable to the Weighted Overlay function. 316 austenitic stainless steel,310 austenitic stainless steel,317l austenitic stainless steel,316l aus-tenitic stainless steel, aluminum (gold plated), aisi 446 ferritic stainless steel, aisi 436 ferritic stainless steel, aisi 444 ferritic stainless stee, aisi 434 ferritic stainless stee,304 austenitic stainless steel, titanium (coated with nitride), a560 (50cr–ni). the density of an object, the tensile strength, the expansions coeffi-cients, conductivity of heat, thermal diffusivity, and fracture toughness are some of the other characteris-tics of bipolar plates that should be considered. From the result it is seen that titanium (coated with ni-tride) is got the first rank whereas is the 310 austenitic stainless steel having the lowest rank. The first ranking titanium (coated with nitride) is obtained with the lowest quality of 310 austenitic stainless steel.

Comparative Assessment of Suggested Dam Sites Using both Analytic Hierarchy Process and Weighted Sum Method for Rainwater Harvesting in Al-Naft Valley, Eastern Diyala, Iraq

The study compares suggested dam sites for rainwater harvesting in the Al-Naft Valley, east of Diyala Governorate, Iraq, near the Iranian border. The digital elevation model, Operational Land Imager data, ArcGIS 10.8, Global Mapper 24, and Surfer 17 software were employed for this purpose. The watershed, predominantly in Iran 70% with 30% in Iraq, was of the sixth order, covering 1443 km². The total surface runoff volume was estimated at 320,000,000 m³/year using the SCS-CN method, which highlighted challenges due to international border crossings. The evaluation of the suggested dam sites depended on 11encompassed morphometric (stream order), hydrological (annual water income), geometric (reservoir capacity, average depth, surface area of reservoir, and safety factor), demographic (number of capita benefiting), economic (relative cost/ storage, road submerging by the lake, distance to roads) and geopolitical criteria (area of lake crossed international borders). Analytic Hierarchy Process and Weighted Sum Method were used for comparison, with input from 35 experts to weight criteria to evaluate six proposed sites (alternatives). The second, third, and fourth proposed dams are classified as large-sized, while the others are medium-sized. The third proposed dam emerged as the most suitable, offering a storage capacity of 165,000,000 m³, representing 51.5% of annual input water. To align storage with annual water input, multiple dams are preferred. The first, third, and sixth proposed reservoirs, with a total capacity of 237,000,000 m³, constitute 74% of the expected annual water input to the watershed.

A comprehensive analysis of the tail-dependent structure of wind loads and its engineering applications

Wind load field characteristics on the roof surface of low-rise buildings based on field measurements have crucial engineering guidance value. In the background, tail-dependence structure from measured wind loads can assist in modeling the joint tail distribution of multivariate wind loads. In this study, the non-parameter estimation method, multi-copula function model and multivariate peak over threshold model are applied to estimate its precise value. The upper tail dependence coefficient's value is around 0.20 when the quantile for p(y) = 0.75. When p(y) = 0.95, the Gumbel copula overestimates the tail-dependence value slightly. Additionally, the lower tail-dependence values estimated by the Clayton copula are around 0.19 at 0.25 quantile. For extreme tail-dependence coefficients, little difference exists in the estimated results by the non-parameter estimation method and the peak over threshold model, in which its value varies from 0.80 to 0.90. Under roof pitch = 5°, its value exhibits some dispersion at different locations. An area weight function is applied to estimate the extreme tail-dependence value between critical regions. Then, the expectation function of tail dependence reaches the peak value in p(x) = 0.50, p(y) = 0.50 and it has different gradients for different variables and tail regions. Additionally, the lower tail dependence structure is significantly stronger than the upper tail dependence for wind loads with negative skewness. For application in wind engineering, potential applications in risk analysis for roof structures, extreme value estimation for local region block wind load, and wind load forecast for unmonitored locations are proposed.

Flatness constraints in the estimation of GNSS satellite antenna phase center offsets and variations

Accurate information on satellite antenna phase center offsets (PCOs) and phase variations (PVs) is indispensable for high-precision geodetic applications. In the absence of consistent pre-flight calibrations, satellite antenna PCOs and PVs of global navigation satellite systems are commonly estimated based on observations from a global network, constraining the scale to a given reference frame. As part of this estimation, flatness and zero-mean conditions need to be applied to unambiguously separate PCOs, PVs, and constant phase ambiguities. Within this study, we analytically investigate the impact of different boresight-angle-dependent weighting functions for PV minimization, and we compare antenna models generated with different observation-based weighting schemes with those based on uniform weighting. For the case of the GPS IIR/-M and III satellites, systematic differences of 10 mm in the PVs and 65 cm in the corresponding PCOs are identified. In addition, new antenna models for the different blocks of BeiDou-3 satellites in medium Earth orbit are derived using different processing schemes. As a drawback of traditional approaches estimating PCOs and PVs consecutively in distinct steps, it is shown that different, albeit self-consistent, PCO/PV pairs may result depending on whether PCOs or PVs are estimated first. This apparent discrepancy can be attributed to potentially inconsistent weighting functions in the individual processing steps. Use of a single-step process is therefore proposed, in which a dedicated constraint for PCO-PV separation is applied in the solution of the normal equations. Finally, the impact of neglecting phase patterns in precise point positioning applications is investigated. In addition to an overall increase of the position scatter, the occurrence of systematic height biases is illustrated. While observation-based weighting in the pattern estimation can help to avoid such biases, the possible benefit depends critically on the specific elevation-dependent weighting applied in the user’s positioning model. As such, the practical advantage of such antenna models would remain limited, and uniform weighting is recommended as a lean and transparent approach for the pattern estimation of satellite antenna models from observations.

Flexible modelling of time-varying exposures and recurrent events to analyse training load effects in team sports injuries

Abstract We present a flexible modelling approach to analyse time-varying exposures and recurrent events in team sports injuries. The approach is based on the piece-wise exponential additive mixed model where the effects of past exposures (i.e. high-intensity training loads) may accumulate over time and present complex forms of association. In order to identify a relevant time window at which past exposures have an impact on the current risk, we propose a penalty approach. We conduct a simulation study to evaluate the performance of the proposed model, under different true weight functions and different levels of heterogeneity between recurrent events. Finally, we illustrate the approach with a case study application involving an elite male football team participating in the Spanish LaLiga competition. The cohort includes time-loss injuries and external training load variables tracked by Global Positioning System devices, during the seasons 2017–2018 and 2018–2019.

On Traub–Steffensen-Type Iteration Schemes With and Without Memory: Fractal Analysis Using Basins of Attraction

This paper investigates the design and stability of Traub–Steffensen-type iteration schemes with and without memory for solving nonlinear equations. Steffensen’s method overcomes the drawback of the derivative evaluation of Newton’s scheme, but it has, in general, smaller sets of initial guesses that converge to the desired root. Despite this drawback of Steffensen’s method, several researchers have developed higher-order iterative methods based on Steffensen’s scheme. Traub introduced a free parameter in Steffensen’s scheme to obtain the first parametric iteration method, which provides larger basins of attraction for specific values of the parameter. In this paper, we introduce a two-step derivative free fourth-order optimal iteration scheme based on Traub’s method by employing three free parameters and a weight function. We further extend it into a two-step eighth-order iteration scheme by means of memory with the help of suitable approximations of the involved parameters using Newton’s interpolation. The convergence analysis demonstrates that the proposed iteration scheme without memory has an order of convergence of 4, while its memory-based extension achieves an order of convergence of at least 7.993, attaining the efficiency index 7.9931/3≈2. Two special cases of the proposed iteration scheme are also presented. Notably, the proposed methods compete with any optimal j-point method without memory. We affirm the superiority of the proposed iteration schemes in terms of efficiency index, absolute error, computational order of convergence, basins of attraction, and CPU time using comparisons with several existing iterative methods of similar kinds across diverse nonlinear equations. In general, for the comparison of iterative schemes, the basins of iteration are investigated on simple polynomials of the form zn−1 in the complex plane. However, we investigate the stability and regions of convergence of the proposed iteration methods in comparison with some existing methods on a variety of nonlinear equations in terms of fractals of basins of attraction. The proposed iteration schemes generate the basins of attraction in less time with simple fractals and wider regions of convergence, confirming their stability and superiority in comparison with the existing methods.

An approximate solution of multi-term fractional telegraph equation with quadratic B-spline basis functions

This paper introduces the Galerkin Method for the approximate solution ofMulti-term Fractional Telegraph Equations (MFTE). The Galerkin Method (GM)is one of the most popular techniques for the solution of Partial Differential Equations (PDEs), and it uses the idea of mapping a solution onto a set of basis functions and then seeking the residual error through minimization. In GM, the weight and basis functions are the same, and as such, the basis functions are selected appropriately to satisfy the given conditions imposed. In this paper, the quadratic B-spline functions are adopted as shape and test functions for resolving the approximate solution of MFTE. Here, the Caputo fractional derivative takes care of the fractional part, and the Gauss-Mamadu-Njoseh quadrature scheme handles numerical integration. Numerical illustrations are examined for single-term and two-term MFTE, respectively, with numerical evidence measured usingL2 and L∞ error norms. Consequently, the resulting numerical evidence, as presented in Tables and Figures, shows the accuracy and reliability of the method. Also, the study examined and presented relevant theorems of convergence and error analyses of method. MAPLE 18 was used for all computational frameworks in this research.

A prospect theory-driven three-way decision framework: Integrating prior probability tolerance and dominance relations in fuzzy incomplete information systems

This study proposes a novel method that integrates Prospect Theory (PT) with a Three-Way Decision (TWD) framework to enhance decision quality in Fuzzy Incomplete Information Systems (FIIS). The method first applies prior probability tolerance dominance relations to manage and evaluate binary relationships among decision options, laying the groundwork for subsequent calculations. Based on this foundation, PT is used to construct objective weight and value functions, effectively reducing uncertainties due to subjective factors in the decision-making process. Unlike traditional methods, this PT-based TWD approach can address incomplete data while fully considering decision-makers’ psychological preferences under risk, enabling more precise and scientific decision support. Extensive experimental studies and comparative analyses demonstrate that this method outperforms existing approaches in terms of stability, effectiveness, and superiority, highlighting its potential for applications in fields with high data diversity and uncertainty, such as healthcare.

Intestinal Drug Absorption After Subarachnoid Hemorrhage and Elective Neurosurgery: Insights From Esomeprazole Pharmacokinetics.

Subarachnoid hemorrhage (SAH) may critically impair cardiovascular, metabolic, and gastrointestinal function. Previous research has demonstrated compromised drug absorption in this group of patients. This study aimed to examine the impact of SAH on gastrointestinal function and its subsequent effect on the absorption of enterally administered drugs, using esomeprazole as a probe drug. Prospective observational cohort study. Academic hospital in Germany. We included 17 patients with high-grade SAH and 17 controls, comparable in age, sex, body weight, and renal function, who underwent elective cranial surgery. None. Both groups received esomeprazole per standard protocol to prevent acid-associated mucosal damage, either orally or through a nasogastric tube. On day 4, esomeprazole was administered IV to estimate oral bioavailability. Esomeprazole serum concentrations were measured on days 1, 3, and 4 in both groups and on day 7 in the SAH group. Patients with high-grade SAH exhibited severely impaired drug absorption. Most patients showed no improvement in intestinal drug absorption even a week after hemorrhage. Following SAH, significantly reduced drug absorption may be attributed to decreased intestinal motility and compromised intestinal mucosal function. Clinicians should anticipate the reduced effectiveness of enterally administered medications for at least seven days after high-grade SAH.

Dynamics of HPAM flow and injectivity in sandstone porous media

Polymer flooding is a prominent chemical enhanced oil recovery (CEOR) method that involves the injection of polymer solution into the oil reservoirs to improve the sweep efficiency and maximize the ultimate oil recovery. Selecting an appropriate polymer type, molecular weight, and concentration is crucial for success of any polymer flooding project. This paper studies the flow behavior of HPAM-based EOR polymers with different molecular weights through porous media. Dynamic adsorption and injectivity tests were performed through 5 Darcies sandpacks using polymer solutions prepared with low (LM; 8–10 MDa) and high (HM; 20–25 MDa) molecular weight polymers. Polymer solutions with different target viscosity values of 7, 15 and 30 cP were flooded through sandpacks at the reservoir temperature of 80 ºC and pore pressure of 1000 psi. The results showed that HM solutions with different target viscosity have higher polymer retention through sandpacks compared to LM solutions. Furthermore, results of residual resistance factor (RRF) measurements were in line with dynamic adsorption tests results. That is, permeability reduction due to irreversible polymer retention was higher when HM polymer solutions were injected. Furthermore, the results showed that although the resistance factor (RF) and in-situ viscosity of HM and LM polymers are in the same range, however, shear thickening regime becomes pronounced in the case of HM polymer with higher target viscosity. Polymer relaxation time measurements, and consequently, Deborah number calculations were performed to describe the shear thickening behavior by polymers viscoelastic characteristics. Results demonstrate that occurrence of shear thickening regime is controlled by Deborah number which is a function of polymer molecular weight, polymer concentration and injection rate. These results shed light on the importance of the selection of optimal polymer molecular weight and concentration during the design of polymer flooding projects.

A parsimonious dynamic mixture for heavy-tailed distributions

Dynamic mixture distributions are convenient models for highly skewed and heavy-tailed data. However, estimation has proved to be challenging and computationally expensive. To address this issue, we develop a more parsimonious model, based on a one-parameter weight function given by the exponential cumulative distribution function. Parameter estimation is carried out via maximum likelihood, approximate maximum likelihood and noisy cross-entropy. Simulation experiments and real-data analyses suggest that approximate maximum likelihood is the best method in terms of RMSE, albeit at a high computational cost. With respect to the version of the dynamic mixture with weight equal to the two-parameter Cauchy cumulative distribution function, the reduced flexibility of the present model is more than compensated by better statistical and computational properties.

A new weighted means of failure rate and associated quantile versions

Abstract In this paper, we define weighted failure rate and their means from the stand point of an application. We begin by emphasizing that the formation of n independent component series system having weighted failure rates with sum of weight functions being unity is same as a mixture of n distributions. We derive some parametric and non-parametric characterization results. We discuss on the form invariance property of baseline failure rate for a specific choice of weight function. Some bounds on means of aging functions are obtained. Here, we establish that weighted increasing failure rate average (IFRA) class is not closed under formation of coherent systems unlike the IFRA class. An interesting application of the present work is credited to the fact that the quantile version of means of failure rate is obtained as a special case of weighted means of failure rate.