Considering that the current method cannot effectively analyze the complex electricity bill credit risk behavior when conducting electricity bill credit risk analysis, the accuracy of electricity bill credit risk anal...
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The study of homeostatic equilibrium is a key concern in several fields, from physiology and biology to medicine and biomedical engineering. control theory approaches can provide effective strategies to model physiolo...
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The study of homeostatic equilibrium is a key concern in several fields, from physiology and biology to medicine and biomedical engineering. control theory approaches can provide effective strategies to model physiological control systems, helping in understanding the dynamics of bio- and physio-logical regulation processes. However, the intrinsic complexity of living systems makes it difficult to identify unified biomodels that can represent a wide variety of physiological systems. In this context, the present work proposes a general framework to model the dynamics and describe the behavior of a wide class of multivariable physiological control systems, from the molecular to the whole-organ scale. The framework adopts a structure based on a closed-loop topology taking into account multiple inputs and outputs and with the negative feedback action intrinsically embedded within the model. The development of such a general model has at least three important repercussions: the first concerns the possibility of better understanding the basic mechanisms common to many physiological systems;the second is to develop a common theoretical framework to enable effective approaches to the analysis and design of synthetic biological control systems;finally, the investigation of the structural properties of the model in a general context, allows a guided and simplified application to specific cases. To this regard, in this paper, the existence, possible uniqueness and stability properties of the homeostatic equilibrium points of the general model are investigated;the theoretical framework is then illustrated through two real-world case-studies: (i) the PI3K/AKT/mTOR pathway nonlinear dynamics, a critical regulator of cellular growth, proliferation, and survival;(ii) the control mechanism of the neuromuscular stretch reflex, among the prime triggers implicated in postural control. Results proved the capability of the proposed framework to capture the intricate dynamics of multivari
Federated learning (FL) has gained attention for enabling efficient distributed learning while maintaining data privacy. However, the data privacy constraint reduces the transparency in the agents' model update ma...
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Federated learning (FL) has gained attention for enabling efficient distributed learning while maintaining data privacy. However, the data privacy constraint reduces the transparency in the agents' model update making the learning process vulnerable to Byzantine attacks. In this paper, a mathematical proof is provided to show that when the traditional model-combining scheme is used, the model will eventually diverge to non-useful solutions in the presence of Byzantine agents independently from their number or their contributions. A low complexity norm-control based aggregation approach is also proposed and shown to converge to the optimal and sub-optimal solutions in the absence or presence of Byzantine nodes, respectively. Monte-Carlo simulations are also conducted to verify and validate the mathematical derivations and the efficiency of the proposed approach in protecting the FL model.
As climate change affects the physicochemical properties of coastal water, the resulting element re-exposure may override the emission reductions achieved by human pollution control efforts. Here, we conduct an analys...
As climate change affects the physicochemical properties of coastal water, the resulting element re-exposure may override the emission reductions achieved by human pollution control efforts. Here, we conduct an analysis the water quality-climate effect over eight consecutive years from 2015 to 2022 along the South China coast combined with CMIP6 Scenario Model Intercomparison Project. Then we utilized a data-driven model to predict the concentrations of trace metals and nutrients over the next 80 years. It is suggested that the acidification process carries the risk of triggering the ocean's buffering mechanisms. During this alkalinity replenishment process, trace metals, such as Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn, in the sediment are released into the water phase, along with Ca2+ and Mg2+. Here, the aim of this study is to show that the nexus of re-exposure-eutrophication-emission reduction with human activities and climate feedback, cannot be ignored in the pursuit of effective environmental governance.
Fatigue cracking is a prevalent distress, affecting the service life of asphalt pavements. Traditional methods for assessing fatigue resistance can be complex and time-consuming, making it essential to implement more ...
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Fatigue cracking is a prevalent distress, affecting the service life of asphalt pavements. Traditional methods for assessing fatigue resistance can be complex and time-consuming, making it essential to implement more proactive approaches during the mix design and/or quality controlprocess. Screening tests, such as the semi-circular bending (SCB) test with the Illinois flexibility index (FI) variant, have gained traction as a viable alternative. Despite its potential, the FI is often shown to exhibit high variability and lacks sensitivity to certain mix design variables. These limitations have prompted alternative dataanalysis methodologies and performance indices to evaluate the cracking potential of asphalt concrete. This study presents a comprehensive evaluation of cracking resistance derived from the SCB test results, where multiple performance indicators, including fracture energy (Gf), flexibility index (FI), cracking resistance index (CRI), toughness index (TI), fracture strain tolerance (FST), and Nflex factor, were adopted. Four polymer- modified, dense-graded asphalt mixtures, varying in aggregate types, gradations, and design gyrations, were tested. The efficacy of selected performance criteria to capture the cracking susceptibility of asphalt mixtures, focusing on consistency and reliability, was assessed. While useful for screening exercises, monotonic tests and associated performance indices often overlook critical behaviors, such as stress relaxation, highlighting the need for methods like cyclic loading tests and viscoelastic modeling to improve performance predictions of asphalt mixtures. Consequently, a comparative approach was initiated by benchmarking the results obtained against established fatigue characterization methods like the uniaxial tension/compression (T/C) fatigue test and viscoelastic continuum damage (VECD) analysis in a controlled laboratory environment. Results revealed varying degrees of correlation between SCB-based indicators a
Typical sensors for rotor position measurement are susceptible to environmental factors and may even cause reliability concerns during online operation. Thus, sensorless control becomes increasingly crucial in motor d...
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Typical sensors for rotor position measurement are susceptible to environmental factors and may even cause reliability concerns during online operation. Thus, sensorless control becomes increasingly crucial in motor drives. To fulfill the precise position estimation of permanent magnet synchronous motors (PMSMs), a novel hybrid-driven position estimation method is proposed in this article. Instead of employing huge neural networks (NNs) for direct position estimation with a laborious offline training process, the preliminary position information is extracted from the designed model-based estimator in the proposed method and fed to the data-driven radial basis function (RBF) NN compensator to predict the position residuals for high-precision position estimation. For the convenience of practical application, an online training scheme based on the gradient descent method is designed for the learning of RBF compensator. Additionally, a domain-related compensation strategy is introduced to enhance the dynamic performance of the proposed method. By combining the respective strengths of model-based and data-driven methods, the proposed method significantly alleviates the parameter-tuning burden in the conventional model-based methods with enhanced estimation precision and addresses the high computational complexity in the data-driven methods with better generalization performance. Finally, real-time experiments are presented to verify the effectiveness and viability of the proposed method.
This article aims to construct and validate a student information literacy evaluation model based on the BP neural network algorithm. In the current information age, the information literacy of students is crucial for...
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Due to the influence of the hydraulic pump, the fluid medium in the pipeline is accompanied by strong periodic pressure pulsation, which is easy to induce large forced vibration in the clamppipeline system. Thus, stud...
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Due to the influence of the hydraulic pump, the fluid medium in the pipeline is accompanied by strong periodic pressure pulsation, which is easy to induce large forced vibration in the clamppipeline system. Thus, studying the vibration characteristics of pipeline systems under fluid pulsation excitation is particularly important. The finite element method based on beam elements has distinct advantages in the modeling of spatial pipelines and complex boundaries. However, its application is often restricted due to its low computational efficiency and inaccuracy in handling fluid pulsation excitation loads. Therefore, in this paper, the measured pressure pulsation functions are taken as inputs, and the vibration response of the pipeline system under fluid pulsation excitation is solved through two-way fluid-structure interaction (FSI) analysis. The validity of the simulation is verified by comparing the results with the experimental data. On this basis, the fluid pulsation excitation forces at different nodes of the pipeline are extracted, and an in-depth analysis of the magnitude and phase distribution patterns of the excitation forces at each node is carried out. Finally, a characterization method of fluid pulsation excitation is proposed, which is based on the node excitation force fitted by two-way FSI analysis. The results indicate that the proposed fluid pulsation excitation expression can approximate the actual fluid pulsation excitation. The amplitude error between the simulation and experimental vibration responses can be controlled within an acceptable range. Specifically, the error under a pressure of 8 MPa is controlled within 20 %, which verifies the effectiveness of the proposed characterization method.
Time series forecasting and anomaly detection are becoming essential in smart manufacturing for prognostics and health management of a machine, especially where traditional methods struggle with the analysis of high f...
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The state-of-the-art modulation strategy of MMC is closely related to the quality of its output voltage waveform and system loss, and is related to whether the entire MMC system can maintain efficient and stable opera...
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