As an important energy storage device, lithium-ion batteries (LIBs) have been widely used in various fields due to their remarkable advantages. The high level of precision in estimating the battery's state of heal...
详细信息
As an important energy storage device, lithium-ion batteries (LIBs) have been widely used in various fields due to their remarkable advantages. The high level of precision in estimating the battery's state of health greatly enhances the safety and dependability of the application process. In contrast to traditional model-based prediction methods that are complex and have limited accuracy, data-driven prediction methods, which are considered mainstream, rely on direct data analysis and offer higher accuracy. Therefore, this paper reviews how to use the latest data-driven algorithms to predict the SOH of LIBs, and proposes a general prediction process, including the acquisition of datasets for the charging and discharging process of LIBs, the processing of data and features, and the selection of algorithms. The advantages and limitations of various processing methods and cutting-edge data-driven algorithms are summarized and compared, and methods with potential applications are proposed. Effort was also made to point out their application methods and application scenarios, providing guidance for researchers in this area.
BACKGROUND:Paediatric critical care nurses face challenges in promptly detecting patient deterioration and delivering high-quality care, especially in low-resource settings (LRS). Patient monitors equipped with data-d...
详细信息
BACKGROUND:Paediatric critical care nurses face challenges in promptly detecting patient deterioration and delivering high-quality care, especially in low-resource settings (LRS). Patient monitors equipped with data-driven algorithms that monitor and integrate clinical data can optimise scarce resources (e.g. trained staff) offering solutions to these challenges. Poor algorithm output design and workflow integration, however, are important factors hindering successful implementation. This study aims to explore nurses' perspectives to inform the development of a data-driven algorithm and user-friendly interface for future integration into a continuous vital signs monitoring system for critical care in LRS.
METHODS:Human-centred design methods, including contextual inquiry, semi-structured interviews, prototyping and co-design sessions, were carried out at the high-dependency units of Queen Elizabeth Central Hospital and Zomba Central Hospital in Malawi between March and July 2023. Triangulating these methods, we identified what algorithm could assist nurses and used co-creation methods to design a user interface prototype. data were analysed using qualitative content analysis.
RESULTS:Workflow observations demonstrated the effects of personnel shortages and limited monitor equipment for vital signs monitoring. Interviews identified four themes: workload and workflow, patient prioritisation, interaction with guardians, and perspectives on data-driven algorithms. The interviews emphasised the advantages of predictive algorithms in anticipating patient deterioration, underlining the need to integrate the algorithm's output, the (constant) monitoring data, and the patient's present clinical condition. Nurses preferred a scoring system represented with familiar scales and colour codes. During co-design sessions, trust, usability and context specificity were emphasised as requirements for these algorithms. Four prototype components were examined, with nurses favouring scor
The accurate prediction of mutual inductance in inductive planar coils is a critical challenge in advancing wireless power transfer (WPT) systems, particularly as traditional analytical methods struggle to balance pre...
详细信息
The accurate prediction of mutual inductance in inductive planar coils is a critical challenge in advancing wireless power transfer (WPT) systems, particularly as traditional analytical methods struggle to balance precision and computational speed in complex, real-world scenarios. This study addresses these limitations by exploring data-driven algorithms for predicting mutual inductance. Additionally, the study offers a robust solution to handle the nonlinearities and dynamic requirements of three-dimensional coil configurations. Seven regression algorithms-linear, polynomial, kernel ridge, decision tree, random forest, support vector and neural network-are evaluated to identify the most effective approach. Key results reveal the superior performance of kernel ridge, support vector and neural network regression models, achieving R2 scores of 0.995, 0.987 and 0.992, respectively. Kernel ridge regression demonstrated the lowest error metrics, with an MAE of 49.624 nH and an RMSE of 86.174 nH, whereas support vector and neural network regression followed closely with slightly higher errors. Conversely, traditional models such as linear regression and decision tree showed significantly higher MAEs and RMSEs, highlighting their inadequacy for handling the complexities of WPT datasets. This research establishes a scalable and accurate framework for mutual inductance prediction, paving the way for improved efficiency in WPT systems.
Accurate state of charge (SOC) estimation is critical to the safe and efficient operation of lithium-ion (Li-ion) batteries. In this work, a novel method that integrates a Random Forest-Least Absolute Shrinkage and Se...
详细信息
Accurate state of charge (SOC) estimation is critical to the safe and efficient operation of lithium-ion (Li-ion) batteries. In this work, a novel method that integrates a Random Forest-Least Absolute Shrinkage and Selection Operator (RF-LASSO) with a window-varying adaptive extended Kalman filter (WVAEKF) is applied to a physics-based battery model to estimate SOC. The algorithm integrates the strengths of data-driven methods and adaptive filtering to enhance the precision of SOC forecasting. The proposed physics-based battery model is a novel equivalent circuit model with diffusion dynamics. This model integrates the diffusion dynamics principle to provide a detailed account of the voltage loss encountered by Li-ion batteries during the diffusion phase. The WVAEKF algorithm's estimation error due to inaccurately capturing the distribution changes of the error innovation sequence and inherent instability of battery model, particularly under dynamic load conditions, is compensated by the introduction of a data-driven RF-LASSO model to improve the accuracy of SOC estimation. The experimental results show that the maximum SOC error of the SOC estimation method proposed in this study is less than 1% under the Dynamic Stress Test (DST) and Federal Urban Driving Schedule (FUDS) conditions. Compared with the conventional AEKF, this method has higher SOC estimation accuracy. Under DST and FUDS conditions at 25 degrees Celsius , the peak error of SOC estimation is significantly reduced by 58.73% and 57.53%, respectively. This improvement highlights the reliability and accuracy of the method in SOC estimation.
This study aims to enhance the precision and efficiency of indoor spatial design for college physical bookstores in the context of the new media environment. To achieve this, a novel intelligent analysis model was dev...
详细信息
This study aims to enhance the precision and efficiency of indoor spatial design for college physical bookstores in the context of the new media environment. To achieve this, a novel intelligent analysis model was developed by integrating the Squares Support Vector Machine (LSSVM). The research analyzes the relationship between the new media environment and bookstore design, identifies key design principles, and establishes performance metrics. The proposed NOA-LSSVM model optimizes design parameters by utilizing a hybrid convergence-divergence search mechanism, achieving improved accuracy and computational efficiency. A case study of Jilin Jianzhu University's bookstore was conducted to evaluate the model's performance. The NOA-LSSVM model was compared with three other optimization algorithms: the Flower Pollination Algorithm (FPA), Whale Optimization Algorithm (WOA), and Sine Cosine Algorithm (SCA). Results showed that the NOA-LSSVM model achieved superior accuracy, with a Mean Absolute Percentage Error (MAPE) of 2.9, significantly lower than FPA (4.6), WOA (3.8), and SCA (4.2). Additionally, the model exhibited faster convergence and enhanced design efficiency, optimizing the bookstore's functional zones and spatial layout to balance dynamic and quiet areas effectively. In conclusion, the NOA-LSSVM model demonstrates a robust capability to optimize indoor spatial design in the new media environment, outperforming traditional methods in accuracy and practicality. This study provides valuable insights for integrating intelligent algorithms into spatial design processes, with the potential for broader applications in other commercial or educational spaces. Future research should focus on extending the model's generalizability and incorporating advanced media technologies for enhanced user experiences.
For unachievable tracking problems, where the system output cannot precisely track a given reference, achieving the best possible approximation for the reference trajectory becomes the objective. This study aims to in...
详细信息
For unachievable tracking problems, where the system output cannot precisely track a given reference, achieving the best possible approximation for the reference trajectory becomes the objective. This study aims to investigate solutions using the Ptype learning control scheme. Initially, we demonstrate the necessity of gradient information for achieving the best ***, we propose an input-output-driven learning gain design to handle the imprecise gradients of a class of uncertain systems. However, it is discovered that the desired performance may not be attainable when faced with incomplete *** address this issue, an extended iterative learning control scheme is introduced. In this scheme, the tracking errors are modified through output data sampling, which incorporates lowmemory footprints and offers flexibility in learning gain *** input sequence is shown to converge towards the desired input, resulting in an output that is closest to the given reference in the least square sense. Numerical simulations are provided to validate the theoretical findings.
Deformation monitoring is a critical task for dam operators to guarantee safe operation. Given an increasing number of extreme weather events caused by climate change, the precise prediction of dam deformations has be...
详细信息
Deformation monitoring is a critical task for dam operators to guarantee safe operation. Given an increasing number of extreme weather events caused by climate change, the precise prediction of dam deformations has become increasingly important. Traditionally, multiple linear regression models have been employed, utilizing in situ data from pendulum systems or trigonometric measurements. These methods sometimes suffer from sparse data, which typically represent deformations only at specific points on the dam, if such data are available at all. Technical advances in multi-temporal synthetic aperture radar interferometry (MT-InSAR), particularly Persistent Scatterer Interferometry (PSI), address these limitations by enabling monitoring in high spatial and temporal resolution, capturing dam deformations with millimeter precision, and providing extensive spatial coverage. This study advances traditional methods of dam monitoring by employing data-driven techniques and integrating Sentinel-1 C-band Persistent Scatterer (PS) time series alongside in situ data. Through a comprehensive evaluation of advanced data-driven approaches, we demonstrated considerable improvements in predicting dam deformations and evaluating their drivers. The analysis provided evidence for the following insights: First, the accuracy of current modeling approaches can be greatly improved by utilizing advanced feature engineering and data-driven model selection. The prediction performance of the pendulum data was improved by utilizing data-driven algorithms, reducing the mean absolute error from 0.51 mm in the baseline model (R2 = 0.92) to as low as 0.05 mm using the full model search space (R2 = 0.99). Although the model accuracy for the PS datasets (MAEmax: 0.81 mm) was about one order of magnitude lower than that for pendulum data, the mean absolute errors could be reduced by up to 0.25 mm. Second, by incorporating freely available PS time series into deformation prediction, dams can be monitore
Background Clinical decision-making is increasingly shifting towards data-driven approaches and requires large databases to develop state-of-the-art algorithms for diagnosing, detecting and predicting diseases. The in...
详细信息
Background Clinical decision-making is increasingly shifting towards data-driven approaches and requires large databases to develop state-of-the-art algorithms for diagnosing, detecting and predicting diseases. The intensive care unit (ICU), a data-rich setting, faces challenges with high-frequency, unstructured monitor data. Here, we showcase a successful example of a data pipeline to efficiently move patient data to the cloud environment for structured storage. This supports individual patient analysis, enables largescale retrospective research, and the development of data-driven algorithms. Methods Since June 2021, ICU data of the Amsterdam UMC have been collected and stored in a third-party cloud environment which is hosted on large virtual servers. The feasibility of the pipeline will be demonstrated with the available data through research and clinical use cases. Furthermore, privacy, safety, data quality, and environmental impact are carefully considered in the cloud storage transition. Findings Over two years, data from over 9000 patients have been stored in the cloud. The availability, agility, computational power, high uptime, and streaming data pipelines allow for large retrospective analyses as well as the opportunity to implement real-time prediction of critical events with machine learning algorithms. Critical events can be accessed by applying keyword search in the natural language data, annotated by the treating team. Besides, the cloud environment offers storage of institutional data enabling evaluation of healthcare. Interpretation The combined data and features of cloud environments offer support for predictive algorithm development and implementation, healthcare evaluation, and improved individual patient care. Funding University of Amsterdam Research Priority Agenda Program AI for Heath Decision-Making. Copyright (c) 2024 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://***/
State of charge (SOC) estimation is crucial for battery management systems (BMS), which relies on accurate battery mathematical models. The conventional equivalent circuit model, however, does not describe the actual ...
详细信息
State of charge (SOC) estimation is crucial for battery management systems (BMS), which relies on accurate battery mathematical models. The conventional equivalent circuit model, however, does not describe the actual electrochemical nonlinear dynamic response of a lithium-ion battery. In this work, a novel a nonlinear equivalent circuit model (NLECM) is established. It is based on an odd random phase multisine signal for parameter estimation. The signal allows parametrization over a bandwidth broader than that of a conventional HPPC signal. Based on the established NLECM model, a window-varying adaptive extended Kalman filter (WVAEKF) with data-driven algorithm is first applied for SOC estimation. The designed WVAEKF can identify variations in the error innovation sequence distribution and modify the window’s length. Learning from a large number of battery operating data, the data-driven algorithm extracts useful features for the estimation of SOC error and improves the accuracy of the SOC estimation. The experimental results show that the error of SOC estimation by WVAEKF with data-driven algorithm is limited to 1% under dynamic stress test (DST) conditions and 0.5C constant current discharge. Compared with artificial neural network and traditional AEKF, the RMSE of the proposed algorithm is reduced by 93 % and 96 % respectively, which shows that the algorithm has higher accuracy under DST conditions .
A data-driven algorithm is proposed for flow reconstruction from sparse velocity and/or scalar measurements. The algorithm is applied to the flow around a two-dimensional, wall-mounted, square prism. To reduce the pro...
详细信息
A data-driven algorithm is proposed for flow reconstruction from sparse velocity and/or scalar measurements. The algorithm is applied to the flow around a two-dimensional, wall-mounted, square prism. To reduce the problem dimensionality, snapshots of flow and scalar fields are processed to derive POD modes and their time coefficients. Then a system identification algorithm is employed to build a reduced order, linear, dynamical system for the flow and scalar dynamics. Optimal estimation theory is subsequently applied to derive a Kalman estimator to predict the time coefficients of the POD modes from sparse measurements. Analysis of the flow and scalar spectra demonstrate that the flow field leaves its footprint on the scalar, thus extracting velocity from scalar concentration measurements is meaningful. The results show that remarkably good reconstruction of the flow statistics (Reynolds stresses) and instantaneous flow patterns can be obtained using a very small number of sensors (even a single scalar sensor yields very satisfactory results for the case considered). The Kalman estimator derived at one condition is able to reconstruct with acceptable accuracy the flow fields at two nearby off-design conditions. Further work is needed to assess the performance of the algorithm in more complex, three-dimensional, flows.
暂无评论