Effectively preventing hanger bending damage during the configuration transformation of the spatial main cables in suspension bridges is a critical challenge, particularly under the influence of construction errors. T...
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Effectively preventing hanger bending damage during the configuration transformation of the spatial main cables in suspension bridges is a critical challenge, particularly under the influence of construction errors. This study proposes an active fault-tolerant control method that integrates real-time data feedback, tolerance interval inversion technology, and a suspended lateral bracing (SLB) system to mitigate the risk of hanger bending damage in real time. The method establishes a dynamic inversion mechanism, utilizing data feedback, constraint function reconstruction, and secondary optimization to compensate for construction errors. This ensures that hangers remain undamaged throughout the transformation process. Construction errors are quantified as intervals, with the lower bound of the reliability interval used to account for extreme disturbances. This transforms the inversion process into a multi-objective optimization problem constrained by the worst reliability conditions. By integrating finite element analysis (FEA), reliability analysis, surrogate modeling, and interval analysis, the proposed approach establishes a direct relationship between design variables and the lower bound of the reliability interval. Case study results demonstrate that the proposed method not only ensures structural performance and hanger safety, but also significantly enhances the constructability of the configuration transformation. Additionally, it provides a larger fault tolerance margin, thereby improving the overall efficiency and safety of the construction process.
The Maxwell distribution is extensively employed in statistical modeling to analyze data, notably in the fields of chemistry, astrophysics, demography, actuarial sciences, economics, industry, and engineering. Recentl...
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The Maxwell distribution is extensively employed in statistical modeling to analyze data, notably in the fields of chemistry, astrophysics, demography, actuarial sciences, economics, industry, and engineering. Recently, the application of the Maxwell data generating process (DGP) has focused extensively on the domain of statistical control charts. The V chart and V SQ chart are often used to identify unexpected changes in the distributional shift of the Maxwell process. The V SQ chart offers considerably better performance than the V chart for detecting moderate to large shifts in the scale parameter. However, the V SQ chart adopts the fundamental structure of the Shewhart monitoring scheme and is insensitive to small alterations in the target parameter. We propose anew control chart, namely, the Maxwell exponentially weighted moving average (MXEWMA) chart, for improved monitoring of quality attributes that are assumed to conform to Maxwell data generation. The factors used to design the parameters of the proposed chart are computed at different false alarm probabilities and across various sample sizes. The effectiveness of the suggested scheme is considered in terms of the different features of the run length (RL) distribution, including the average, median and standard deviation. A comparative study of the MXEWMA chart with the existing V SQ chart was performed across various sample sizes. The comparative analysis showed that the MXEWMA chart is an effective alternative and performs well in detecting reasonably small shifts in the parameter. Simulated data are employed to describe the computational procedure of the MXEWMA scheme. The simulation analysis demonstrated that the MXEWMA chart outperforms the existing method in identifying slight changes in the studied parameters. A real dataset is also considered to support the theoretical part of the work.
In this article, an improved model predictive torque control (MPTC) method is proposed for switched reluctance motors (SRMs) based on variable hyperbolic tangent function modeling. First, the complete modeling of flux...
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In this article, an improved model predictive torque control (MPTC) method is proposed for switched reluctance motors (SRMs) based on variable hyperbolic tangent function modeling. First, the complete modeling of flux-linkage characteristics is developed based on finite measurement data using a variable hyperbolic tangent function. It could be found that only two parameters are necessary to obtain the corresponding flux-linkage at a given rotor position, significantly reducing the storage space required during the implementation process. Additionally, based on the inductance characteristics, an improved switching table is proposed with three switching states. Meanwhile, the operation principles of MPTC are presented with the improved switching table. Finally, the simulation analysis and experimental results are conducted on a four-phase 8/6 SRM to validate the effectiveness of the proposed improved MPTC. The verification results demonstrate that the proposed method can effectively reduce storage space, lower switching frequency, and exhibit minimal torque ripple.
Background: Patient-specific lumbar spine models are crucial for enhancing diagnostic accuracy, preoperative planning, intraoperative navigation, and biomechanical analysis of the lumbar spine. However, the methods cu...
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Background: Patient-specific lumbar spine models are crucial for enhancing diagnostic accuracy, preoperative planning, intraoperative navigation, and biomechanical analysis of the lumbar spine. However, the methods currently used for creating and analyzing these models primarily involve manual operations, which require significant anatomical expertise and often result in inefficiencies. To overcome these challenges, this study introduces a novel method for automating the creation and analysis of subject-specific lumbar spine models. Methods: This study utilizes deep learning algorithms and smoothing algorithms to accurately segment CT images and generate patient-specific three-dimensional (3D) lumbar masks. To ensure accuracy and continuity, vertebral surface models are then constructed and optimized, based on these 3D masks. Following that, model accuracy metrics are calculated accordingly. An automated modeling program is employed to construct structures such as intervertebral discs (IVD) and generate input files necessary for Finite Element (FE) analysis to simulate biomechanical behavior. The validity of the entire lumbar spine model produced using this method is verified by comparing the model within vitro experimental data. Finally, the proposed method is applied to a patient-specific model of the degenerated lumbar spine to simulate its biomechanical response and changes. Results: In the test set, the neural network achieves an average Dice coefficient (DC) of 97.8%, demonstrating high segmentation accuracy. Moreover, the application of the smoothing algorithm reduces model noise substantially. The smoothed model exhibits an average Hausdorff distance (HD) of 3.53 mm and an average surface distance (ASD) of 0.51 mm, demonstrating high accuracy. The FE analysis results agree closely within vitro experimental data, while the simulation results of the degradation lumbar model correspond with trends observed in existing literature.
Underground space development has significantly increased the depth, scale, and complexity of foundation pit engineering. However, monitoring systems lack mechanical analysis models and fail to predict and control con...
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Underground space development has significantly increased the depth, scale, and complexity of foundation pit engineering. However, monitoring systems lack mechanical analysis models and fail to predict and control construction risks. Additionally, the foundation pit model could not be updated based on on-site observed data, leading to inaccurate predictions. This study proposes a DT modeling framework for foundation pits, which is used to simulate, predict, and control the risks associated with the entire excavation process. Consequently, based on the DT modeling framework, a DT foundation pit model (DTFPM) was established using modeling and updating algorithms. This study summarizes and identifies the key modeling parameters of foundation pits. A parametric modeling algorithm based on ABAQUS (v2020) was developed to drive the excavation pit modelingprocess within seconds. Furthermore, an inverse analysis optimization algorithm based on genetic algorithms (GA) and real-time observed deformation was employed to update the elastic modulus of the soil. The algorithm supports parallel computing and can converge within 10 generations. The prediction error of the model after inverse analysis can be reduced to within 10%. Finally, the authors applied DTFPM to establish an intelligent monitoring system. The focus is on real-time and predictive warnings based on the monitoring deformation of the current construction step and the updated model. This study analyzes a Beijing project case to verify the effectiveness of the system, demonstrating the practical application of the proposed method. The results showed that the DTFPM could accurately simulate the deformation behavior of the foundation pit. The system could provide more timely and accurate safety warnings. The proposed method can potentially contribute to the intelligent construction of foundation pits in the future, both theoretically and practically.
Optical emission spectroscopy (OES) data is essential for virtual metrology, enabling accurate predictions of wafer performance in plasma etching processes. This approach not only reduces the need for physical measure...
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Optical emission spectroscopy (OES) data is essential for virtual metrology, enabling accurate predictions of wafer performance in plasma etching processes. This approach not only reduces the need for physical measurements of product quality, leading to significant resource savings, but also supports improved decision-making, particularly in processcontrol and quality assurance. To exploit the consecutive nature of OES data, we propose a prediction method based on a functional approach using multivariate functional partial least squares regression, coupled with dimension reduction and a novel outlier detection technique via functional independent component analysis. The proposed approach improves prediction performance by capturing the continuous nature of OES data and effectively extracting the components that describe the data structure. Numerical experiments, including simulation studies and real-world applications of OES data, demonstrate the effectiveness of the proposed method through superior prediction performance, as evidenced by low RMSE and MAE values, particularly in the presence of outliers.
SENTINEL (SEnsor NeTwork INtelligent Emissions Locator) is an application developed in R Shiny to support emerging user groups of lower cost fenceline sensors, such as those monitoring volatile organic compound or met...
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SENTINEL (SEnsor NeTwork INtelligent Emissions Locator) is an application developed in R Shiny to support emerging user groups of lower cost fenceline sensors, such as those monitoring volatile organic compound or methane concentrations inside and near industrial facilities or for emergency response applications. During deployment, sensors collect a large quantity of high-frequency pollutant concentration data, time-aligned meteorological information, and sensor performance indicators. These sensors can collect a quantity of data that is overwhelming for users to process and understand without designated software. The SENTINEL application provides users with a consistent framework for processing, analyzing, and visualizing fenceline sensor data. SENTINEL temporally aggregates data for synthesized analysis and interpretation. Quality assurance screening automatically removes anomalous datapoints and a baseline correction algorithm reduces background drift in pollutant concentration data. SENTINEL offers streamlined sensor dataanalysis through a user-friendly graphical user interface that supports interpretation of source emission data and sensor-triggered field samples.
This paper presents a discrete counterpart of the mixture exponential distribution, namely discrete mixture exponential distribution, by utilizing the survival discretization method. The moment generating function and...
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This paper presents a discrete counterpart of the mixture exponential distribution, namely discrete mixture exponential distribution, by utilizing the survival discretization method. The moment generating function and associated moment measures are discussed. The distribution's hazard rate function can assume increasing or decreasing forms, making it adaptable for diverse fields requiring count datamodeling. The paper delves into two parameter estimation methods and evaluates their performance through a Monte Carlo simulation study. The applicability of this distribution extends to time series analysis, particularly within the framework of the first-order integer-valued autoregressive process. Consequently, an INAR(1) process with discrete mixture exponential innovations is proposed, outlining its fundamental properties, and the performance of conditional maximum likelihood and conditional least squares estimation methods is evaluated through a simulation study. Real dataanalysis showcases the proposed model's superior performance compared to alternative models. Additionally, the paper explores quality control applications, addressing serial dependence challenges in count data encountered in production and market management. As a result, the INAR(1)DME process is employed to explore control charts for monitoring autocorrelated count data. The performance of two distinct control charts, the cumulative sum chart and the exponentially weighted moving average chart, are evaluated for their effectiveness in detecting shifts in the process mean across various designs. A bivariate Markov chain approach is used to estimate the average run length and their deviations for these charts, providing valuable insights for practical implementation. The nature of design parameters to improve the robustness of process monitoring under the considered charts is examined through a simulation study. The practical superiority of the proposed charts is demonstrated through effective mode
Digital twin technology in the manufacturing process faces challenges like integrating diverse data sources and managing real-time data flow. To address this, we propose a novel three-layer knowledge graph architectur...
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Digital twin technology in the manufacturing process faces challenges like integrating diverse data sources and managing real-time data flow. To address this, we propose a novel three-layer knowledge graph architecture to enhance digital twin modeling for manufacturing processes. This architecture consists of a concept layer that structures key information into a knowledge network, a model layer that aligns digital and physical parameters, and a decision layer that leverages model and real-time data for decision support. Validated in aero-engine blade production, this system integrates multi-source data, enhances predictive analysis and anomaly detection, and supports processcontrol and quality management. Over a 5-month validation period, the maximum contour error precision of the blades improved from 0.073 mm to 0.062 mm, and the product qualification rate increased from 81.3% to 85.2%. This demonstrates the system's robust capability for advancing digital twin utilization in manufacturing, highlighting its potential for future improvements.
Business processes require continuous changes or interventions to remain efficient and competitive over time. However, implementing these changes-such as reordering or adding new tasks- can negatively affect the overa...
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ISBN:
(纸本)9783031790584;9783031790591
Business processes require continuous changes or interventions to remain efficient and competitive over time. However, implementing these changes-such as reordering or adding new tasks- can negatively affect the overall process performance. A longstanding problem in Business process Management is that of forecasting ex-ante the values that process performance measures will assume after implementing changes. To achieve this, the concept of Digital process Twins, which extends the well-established Digital Twin paradigm, paves the way for new interesting opportunities. Digital process Twins enable enhanced what-if analysis by virtually predicting process performance under various changes, thus allowing for informed decision-making before actuating process changes in the real world. However, despite recognition as one of the new key enablers of modern process re-engineerization, a comprehensive approach to implementing Digital process Twins is still lacking. This paper proposes a novel conceptual architecture for deploying Digital process Twins to address this gap. Additionally, we introduce Dolly, a framework that implements such conceptual architecture using a multi-modeling approach combining domain data and processmodeling along with a data-driven process simulation technique.
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