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Management of metabolic disorders involves continuous monitoring of physiology. The growing use of glucose sensors, insulin pumps, and other wearable devices, as well as smartphone-based decision support apps, generates large amounts of real-time data, making diabetes a data-rich domain conducive to digital twin implementation. Mechanistic models of glucose–insulin dynamics have been developed in diabetes research, providing a solid foundation for developing digital twin representations of individual patients' metabolic processes. Artificial intelligence (AI) will play a role in improving the accuracy of digital twin technologies and enable their adaptation and personalization. Case studies have demonstrated that personalized approaches that leverage digital twin technology hold promise for optimizing the management of diabetes by tailoring interventions to individual patients' needs and characteristics. Digital twin technology is emerging as a transformative paradigm for personalized medicine in the management of chronic conditions. In this article, we explore the concept and key characteristics of a digital twin and its applications in chronic non-communicable metabolic disease management, with a focus on diabetes case studies. We cover various types of digital twin models, including mechanistic models based on ODEs, data-driven ML algorithms, and hybrid modeling strategies that combine the strengths of both approaches. We present successful case studies demonstrating the potential of digital twins in improving glucose outcomes for individuals with T1D and T2D, and discuss the benefits and challenges of translating digital twin research applications to clinical practice. [ABSTRACT FROM AUTHOR]

For a chemical looping hydrogen generation system, the set of input gas flow rate needed to be adjusted on the reactivity of oxygen carriers, in order to guarantee gas conversion and to obtain higher hydrogen purity. However, the oxygen carriers often decayed upon repeated cycles, leading to pressing need for dynamic alignment between oxygen carrier reactivity and process parameters. Herein, we propose a reaction optimization control method based on machine learning methods that can establish a real-time matching system between the flow rate of input gas and the reactivity of oxygen carriers. The results show that the prediction of hydrogen yield from oxygen carriers when using the optimized Gradient Boosting Decision Tree model is in general agreement with the experimental results (R2 = 0.87, MAE = 0.49). Based on high-precision prediction results, the method is capable of realizing the input gas flow based on the predicted hydrogen production in real time in less than 10s and realizing digital twin with the expansion of the dataset. We envision that the proposed control method can accelerate the industrial application of chemical looping hydrogen generation by predicting accurate operating parameters that can reduce fuel costs and guarantee reactivity of oxygen carriers. • Interpretable relationship between reaction variables and cyclic hydrogen production through machine learning modeling. • Hyperparameter optimization of machine learning models to solve overfitting problems. • The predicted hydrogen production for the new input oxygen carriers is in general agreement with the experimental results. • Digital twin system solves the problem of unstable reduction depth in chemical looping hydrogen production. [ABSTRACT FROM AUTHOR]

The catalytic hydrogenation of carbon dioxide (CO 2) to methanol presents a significant opportunity for both mitigating climate change and producing a valuable chemical feedstock. While existing reviews delve into diverse modeling strategies, the role and potential of machine learning (ML) approaches remain largely unexplored. This review addresses the gap by comprehensively exploring the mechanism, workflow, and application of ML models in the methanol production process. The review highlights the significance of ML application in catalytic CO 2 hydrogenation for methanol synthesis, emphasizing process optimization, predicting methanol performance indicators, thermodynamic modeling, reaction kinetics, and assessing catalyst activity. Furthermore, the review delves into cutting-edge approaches like hybrid models, gray-box models, and digital twins, showcasing their potential to revolutionize the methanol production process. This comprehensive review serves as a valuable resource for forthcoming research aimed at optimizing the CO 2 conversion process to efficiently and sustainably produce methanol. [Display omitted] • Machine learning models are extensively employed in catalytic hydrogenation to produce methanol. • This review is dedicated to the analysis and synthesis of these models as well as to their applications. • ML exhibits high accuracy in modeling CO 2 hydrogenation into methanol. • ML models predict key performance indicators of methanol and optimize reaction conditions. • Innovative ML, gray box, digital twin, and Hybrid algorithms leverage vast databases in this domain. [ABSTRACT FROM AUTHOR]

With the ever increasing number of active satellites in space, the rising demand for larger formations of small satellites and the commercialization of the space industry (so-called New Space), the realization of manufacturing processes in orbit comes closer to reality. Reducing launch costs and risks, allowing for faster on-demand deployment of individually configured satellites as well as the prospect for possible on-orbit servicing for satellites makes the idea of realizing an in-orbit factory promising. In this paper, we present a novel approach to an in-orbit factory of small satellites covering a digital process twin, AI-based fault detection, and teleoperated robot-control, which are being researched as part of the "AI-enabled Cyber–Physical In-Orbit Factory" project. In addition to the integration of modern automation and Industry 4.0 production approaches, the question of how artificial intelligence (AI) and learning approaches can be used to make the production process more robust, fault-tolerant and autonomous is addressed. This lays the foundation for a later realization of satellite production in space in the form of an in-orbit factory. Central aspect is the development of a robotic AIT (Assembly, Integration and Testing) system where a small satellite could be assembled by a manipulator robot from modular subsystems. Approaches developed to improving this production process with AI include employing neural networks for optical and electrical fault detection of components. Force sensitive measuring and motion training helps to deal with uncertainties and tolerances during assembly. An AI-guided teleoperated control of the robot arm allows for human intervention while a Digital Process Twin represents process data and provides supervision during the whole production process. Approaches and results towards automated satellite production are presented in detail. • An automated production system for modular small satellites is proposed. • Central element is a force-sensitive robotic assembly, integration & testing system. • AI and machine learning approaches are applied to make the process more robust. • A digital process twin supervises the autonomous production. • A multi-modal shared control approach allows human teleoperation if required. [ABSTRACT FROM AUTHOR]

This research leverages the potential of digital twin technology to present a novel method of predictive maintenance for 6G communication networks. With the increasing need for 6G networks to be consistently reliable and always available, this essay emphasises the need for more advanced maintenance techniques. The seamless integration of digital twin technology makes it possible to monitor, analyse, and simulate the 6G network in real time. This innovation makes it easier to use artificial intelligence to fine-tune maintenance schedules and anticipate maintenance requirements in advance. The paper fervently promotes the use of digital twin technology as a vital instrument for raising the bar for maintenance requirements in the context of 6G networks. [ABSTRACT FROM AUTHOR]

Pressure swing adsorption(PSA) based gas separation technology is widely applied in chemical industries, especially in hydrogen purification. Its complex mechanism and non-steady state feature restrict the separation performance adjustment and application on efficient gas utilization. Process simulation, machine learning and modelling combined innovating gas management methodology is proposed in this paper to perform accurate gas separation for natural gas based syngas mixture. VB script program is employed to drive Aspen adsorption simulation, and then classical and regression tree(CART), polynomial regression(PNR) and surrogate model are comprehensively used to perform machine learning. Consequently, the coefficient matrix is obtained to quantify the separation performance. This method holds the potential for broader application in refineries and SPCs hybrid hydrogen network, facilitating the comprehensive utilization of hydrogen containing gases. Case study results show this methodology can conserve natural gas and gas productivity by 21.3 %, as well as carbon emission by 8211.6 Nm3/h. This work highlights the promising application of digital twin technology within the chemical industry, showcasing how process simulation, machine learning, and modeling can collectively revolutionize gas management and resource conservation. [Display omitted] • Novel PSA based gas allocation instead of gas separation technology. • Simulation, modelling and machine learning combined gas accommodating methodology. • An insight technology for integration of refinery and SPC. • A novel gas allocation method for zero waste of hydrogen. • An insight application of digital twin technology for gas efficient utilization. [ABSTRACT FROM AUTHOR]

Software-Defined Radios are radio communications devices that have been growing and developing on a larger scale in recent years. Communications are intrinsically embedded in our day by day, thus presenting a higher motivation to use software-defined radios due to its attractive cost. However they present technical limitations. This paper addresses this problem, which is the non-linearity behaviour of gain and frequency in the LimeSDR-USB. That is, this equipment is used to produce a FM signal with an associated frequency and gain before being parameterised according to the internal parameters of each software-defined radio. Each software-defined radio presents a value of frequency and gain of its own, which correlates to the generated signals at the output level. To avoid this, machine learning networks were used, in which networks were trained to adapt to the non-linearity of these devices and correct it without the user noticing. This way, the user sets a desired frequency and gain in a signal, at the output of the software-defined radios, and a neural network calculates which values the software-defined radios should be parameterised, thus mitigating the non-linearity behaviour. This paper presents the evaluation of a laboratory prototype based on low-cost commercial software-defined radios equipment, to replace an expensive metrologically calibrated equipment used for radio frequency tests on a new concept of industrial test station, with description of the integration of Digital Twins, with their physical and virtual parts. [ABSTRACT FROM AUTHOR]

Tailings dam failures cause catastrophic impact on the environment and surrounding communities. Incidences of failure in the recent past have caused industrialists and researchers to seek innovative ways for proactively managing their safety and disaster mitigation. Given Industry 4.0 technologies now available, researchers are looking to develop digital tools for cost-effective, realtime monitoring of tailings dams. However, published literature indicates that a reliable framework is still lacking. This paper proposes a framework for developing a data-driven system for monitoring tailings dam stability and early warning detection. The framework relies upon digital twin simulation and machine-learning (ML) techniques, and comprises four main components: realtime data collection, digital twin modelling, ML-based early detection and prediction, and intelligence-driven decision-support. Sensors gather real-time geophysical data from monitored structure, and the digital twin uses this data to simulate dam behaviour. ML algorithms analyse the data and simulations to enable early detection of instability and failure prediction. Literature suggests that digital twin and ML-based approaches may have advantages over traditional monitoring techniques and other AI-based methods. The paper concludes with a discussion of the framework's limitations, opportunities for improvement, and potential for application in mining and geotechnical engineering. The paper serves as a basis for model development and future research. [ABSTRACT FROM AUTHOR]

While the Metaverse is becoming a popular trend and drawing much attention from academia, society, and businesses, processing cores used in its infrastructures need to be improved, particularly in terms of signal processing and pattern recognition. Accordingly, the speech emotion recognition (SER) method plays a crucial role in creating the Metaverse platforms more usable​ and enjoyable for its users. However, existing SER methods continue to be plagued by two significant problems in the online environment. The shortage of adequate engagement and customization between avatars and users is recognized as the first issue and the second problem is related to the complexity of SER problems in the Metaverse as we face people and their digital twins or avatars. This is why developing efficient machine learning (ML) techniques specified for hypercomplex signal processing is essential to enhance the impressiveness and tangibility of the Metaverse platforms. As a solution, echo state networks (ESNs), which are an ML powerful tool for SER, can be an appropriate technique to enhance the Metaverse's foundations in this area. Nevertheless, ESNs have some technical issues restricting them from a precise and reliable analysis, especially in the aspect of high-dimensional data. The most significant limitation of these networks is the high memory consumption caused by their reservoir structure in face of high-dimensional signals. To solve all problems associated with ESNs and their application in the Metaverse, we have come up with a novel structure for ESNs empowered by octonion algebra called NO2GESNet. Octonion numbers have eight dimensions, compactly display high-dimensional data, and improve the network precision and performance in comparison to conventional ESNs. The proposed network also solves the weaknesses of the ESNs in the presentation of the higher-order statistics to the output layer by equipping it with a multidimensional bilinear filter. Three comprehensive scenarios to use the proposed network in the Metaverse have been designed and analyzed, not only do they show the accuracy and performance of the proposed approach, but also the ways how SER can be employed in the Metaverse platforms. • An octonion based nonlinear echo state network framework is proposed. • The proposed approach is developed to analyzing hypercomplex problems. • Three practical scenarios have been proposed to SER in the Metaverse. • Developed approach is successfully tested on EMODB. [ABSTRACT FROM AUTHOR]

Urbanisation is leading to a concentration of growing city populations that contribute significantly to economic growth, while becoming epicentres of waste generation, greenhouse gas emissions, and food consumption. Nutrient smart city circular economy is currently an understudied intersection of growing city populations of food consumers, nutrient recovery technologies, Internet of Things (IoT), and agriculture. Meanwhile, machine learning has exploded with popularity over the years, with many circular economy literatures examining its usefulness in its predictive qualities to support management, optimisation, and recovery of useful resources from organic waste. This review paper examines advancements in machine learning for macronutrient recovery in city organic waste systems for a circular economy. The use of ML will greatly improve the scalability, transparency, productivity and accuracy of nutrient: recovery technologies, logistics, dissemination, and reuse. ML can also be combined with hardware to automate tedious waste separation, recovery and agricultural tasks using drones, hydroponics and satellites. Meanwhile, crop yields, nutrient demand-supply efficiencies, food security, environmental soil monitoring, and prosumer involvement could all increase. However, ML applications for urine, anaerobic digestion and prosumer economics are lacking. [Display omitted] • Lack of ML urine, membrane-AD, and prosumer studies for nutrient recovery. • IoT hardware, drones, democratised data sharing to address ML underfitting. • Lack of digital twins; CE BIM; good technologies and economics were barriers. • ML could increase transparency and food security for building consumer trust. • ML IoT to predict nutrients for soil, hydroponics, water treatment and farming. [ABSTRACT FROM AUTHOR]

• This study proposes an hour-ahead demand response (DR) for PV-based smart homes utilizing the AI method in digital twin while taking into account customer energy consumption and discomfort; • This study adopts a MARL approach for ensuring optimum and decentralized decision-making among several devices; • This study presents a steady cost prediction method utilizing ANN for overcoming the uncertainties in upcoming costs; • This study also compares the energy prices under 2 various scenarios including and excluding AI-enabled DR. Energy management (EM) systems need to have the flexibility to take the optimum real-time decision in the face of constantly varying market factors. Demand response (DR) has become the newest method of improving the performance and reliability of the electrical system. Here, an hour-ahead DR algorithm is proposed for EM at home. This paper presents an artificial neural network approach that uses stable cost predictions as a method for dealing with upcoming price uncertainties. For making optimum and decentralized decisions for various household devices, multi-agent reinforcement learning has been used along with predicted upcoming costs. This paper conducts the simulation with shiftable, non-shiftable, and controllable loads to determine the effectiveness of this suggested EM strategy. Based on the outcomes of the experiments, this suggested DR algorithm has capable of handling EM for a number of devices, minimizing consumer electricity expenses and discomfort prices, and helping the consumer considerably reduce its energy expenses in comparison to a benchmark using no DR. [ABSTRACT FROM AUTHOR]

• Evaluating the impact of a cyber-vulnerability on device-level resilience of solar-based networks. • Designing a structure for assessing device resiliency using controller code verification in digital twin environment. • Determining the effect on microgrid resilience applying a new machine learning based cyber-physical resiliency metric (CPRM). • Adjusting control actions to improved situational awareness of solar-based networks. Cyber-attacks (CAs) on electrical networks in presents of renewable energies, particularly solar energy, have become more complex and sophisticated over the past few years by making severe system outages. In light of increased automation in solar-based energy industries, a holistic cyber-physical infrastructure must be considered to predict the effect of CAs on electrical networks and the ways to enhance its resilience. The present study examines the resilience characteristics at the equipment area of the diverse control methods and their effect on the outage severity of the smart grid using digital twins (DT) simulation technology. The paper presents a machine learning based metric for measuring the resilience of cyber-physical features that considers device-level characteristics, vulnerabilities, and system models. Resiliency refers to a system's capability of providing energy even during severe contingencies and relates to the ability to resist, forecast, and recover. An example based on the newest CA against Ukraine has been provided and simulated on DT environment. A case study is proposed to illustrate how cyber-physical resilience metrics can be applied to improve operators' situational awareness and provide more proactive or corrective control measures for improving resilience. [ABSTRACT FROM AUTHOR]

• A safe framework for the optimum scheduling of renewable hybrid AC-DC MGs is proposed. • A digital twin model is developed to model the complexities of the renewable energy sources. • To ensure system security, an intrusion detection system according to a sequential assumption test is presented. The current study considers numerous renewable energy resources, distributed power generation units, energy storage, and plug-in hybrid electric vehicles (PHEV) in order to propose a reliable large-scale energy management framework that can be applied to islanded and grid-connected operations of renewable hybrid AC-DC microgrids (MGs). The framework uses a bat optimization algorithm (BOA) for minimizing the operating costs of the network and in addition introduces an intrusion detection system (IDS) according to the sequential hypothesis testing (SHT) method for detecting identity-enabled cyber-attacks (i.e classification of Sybil attacks, masquerading attacks) on the wireless-enabled advanced metering infrastructures (AMI). The suggested IDS uses the received signal strength (RSS) amount for distinguishing various signal resources and detecting cyberattacks. An IEEE 33-bus testing system has been used to construct a real-time hybrid MG in order to determine the reliability and efficiency of the suggested framework. [ABSTRACT FROM AUTHOR]

The sixth-generation (6G) technology of mobile networks will establish new standards to fulfill unreachable performance requirements by fifth-generation (5G) mobile networks. This is due to the high requirements for more intelligent network, ultra-lower latency, extreme network communication speed, and supporting massive number of various connected applications. In the long term, the convergence of various business developments with communication platforms, as initiated by 5G, will exaggerate and highlight areas where 5G's capabilities will fall short of performance requirements. Motivated by the development of applications in massive connections, future networks, developments, and technological advancements for mobile communications that go beyond fifth-generation (B5G) networks are being developed. In this context, highly immersive applications are demanded, such as three-dimensional (3D) communications, digital twins, or massive extended reality (XR)/virtual reality (VR) applications, which will need 6G capabilities to be realized at scale to be commercially feasible. Mainly, we anticipate that only the upcoming 6G networks will be capable of running extremely high-performance connectivity with massive numbers of connected devices, even under laborious scenarios such as extreme density, diverse mobility, and energetic environments. In this article, we look at the most recent trends and future emerging trends that are possible to operate 6G network. Paper aims to provide more inclusive and brief review about 6G mobile communication technology in one survey paper. Initially, a comprehensive overview of the 6G system is introduced in terms of visions, drivers, requirements, architecture, and usage scenarios required to enable 6G applications. After that, the opportunities and advantages of 6G mobile technology has been discussed. Further, the promising new techniques that enable 6G technology has been highlighted. This is followed by a potential discussion of challenges and research directions. This article is envisioned to serve as an informative guideline to stimulate interest and further studies for subsequent research and development of 6G networks. Paper will enable the readers to briefly figure out the key requirements, targets, that will be need and the applications, advantages, and opportunities that can be offered as well as the challenges that need to be addressed before the implementation of this new technology. [ABSTRACT FROM AUTHOR]

• An analysis of the system's effectiveness and the attacks' impacts from both a financial and social standpoint has been presented. • Wald's Sequential hypothesis testing (SHT) process is used to propose a straightforward approach for detecting DIA. • SHTs are widely used in the manufacturing sector to detect defective parts. Microgrids (MG) is originally designed to make Smart Grids more energy-efficient and reliable. The MG represents a complex cyber-physical system whose functioning is driven by the interaction of physical actions and computational elements, making it vulnerable to many forms of malicious cyber-attack. This study considers the effect of data integrity attack (DIA) on the performance of hybrid MGs, an important cyber threat to microgrids (MGs). Further, this paper develops a new process using sequential hypothesis testing (SHT) for detecting DIA on renewable energy resources and improving the security of information in hybrid MGs. By using a binary sample generated from the suggested approach, an analysis statistic is computed and afterward compared to 2 thresholds for deciding between the 3 options. On the measured energy production of renewable energy sources such as wind turbines, DIAs of various severity levels have been conducted for assessing the impact of DIAs on hybrid MG security. A standard IEEE test system has been used to evaluate the efficiency of the suggested process. [ABSTRACT FROM AUTHOR]

• This paper examines a reinforcement learning (RL) method that uses 2steps-ahead to schedule the batteries and PV. • Develop an essential architecture to make multi-criteria decisions via an individual user. • Increase the battery's usage at peak times and increase the wind turbine's and PVs usage for local consumption. • Reinforcement learning algorithms modeling in digital twin to select the optimum battery planning measures based on forecasts of wind power and photovoltaic availability. This research study aims to investigate the microgrid operation for distributing energy including of a local user, a wind turbine, 5 photovoltaics (PV), and a battery, which is linked by a transformer to the external network. This paper examines a reinforcement learning (RL) method that uses 2steps-ahead to schedule the batteries, which is essential for achieving the objective of the users. There is an essential architecture to make multi-criteria decisions via an individual user to increase the battery's usage at peak times and increase the wind turbine's usage for local consumption. RL algorithms select the optimum battery planning measures based on forecasts of wind power and photovoltaic availability. Through the suggested learning, the user can better understand the optimum battery planning measures for various time-varying environment factors. By using the proposed architecture, smart users are capable of learning the uncertain environment and selecting optimum energy management measures based on their experiences. [ABSTRACT FROM AUTHOR]

• A combined EHOA and SVM has been used to perform an efficient DSM. EHOA has been applied to optimize the battery's energy storage and determine its capacity. • Using optimal data from the EHOA, SVMs are trained. This type of training can be applied to batteries in small-scale industries; • EHOA and SVM can be combined to improve the electricity cost when regarding the battery capacity. • Low-cost production per unit is provided by the suggested method in Digital Twin. The key element of tomorrow's smart islanded microgrids (SMG) is Demand Side Management (DSM). Global energy awareness has led to an increase in SMGs' performance and peak balancing capabilities. DSMs are the control layout in these grids, and they aim at optimizing loads in various ways. The SMG includes batteries and distributed photovoltaics. This paper combines an Elephant Herding optimization algorithm (EHOA) and support sector machine (SVM) to the decision-making method in batteries for reducing the electric bill. EHOA could be an effective method for finding a nearly optimum solution to the load scheduling issue in order to reduce the consumers' expenses. Particularly, energy costs could be decreased if the consumer responds to prices that vary with the time of day. Therefore, The EHOA has been applied to assign the battery's optimum energy storage range. The SVM has been trained as a powerful machine learning method using optimal information from the EHOA. It has been employed to determine the amount of energy that has been transmitted into and out of batteries in order to take the lowest possible electric bills. In comparison to the current approach of 2.3 at the consumption of 8.2 kWh/day, the cost of the suggested method of mean generation oscillation (G o s c ) has been equated to 2.27 dollars for the residential load. EHOA-SVM decreases 11.2% of energy costs, thereby assisting the decision-maker to balance the stability of demand-side measures. [ABSTRACT FROM AUTHOR]

• Develop a novel approach called SEH that represents multi-carrier energy systems operating in the SG environments. • The optimum size of the important equipment of SEH such as transformers, ACHs, boilers, and CHP have been considered. • An RL method has been proposed to solve the optimization issue in this article, and also the problem is described as reward function, action space, and state space. • Three criteria as net present value (NPV), rate of return (ROR), and dynamic payback period (DPP) have been applied to approximate the efficiency of the project in the Discounted cash flow (DCF). • The residential customer as an SEH is considered to validate the proposed optimization approach. Getting equipped by highly new smart technologies, Energy Hubs (EHs) and Smart Grids (SGs) are gaining interest these days. Energy management will advance over time as a result of the interaction impact among power and natural gas grids, and the use of smart technology for communications. The present study proposes a novel approach entitled Smart EH (SEH) for modeling multi-carrier energy systems in SG environments. Furthermore, this paper determines the optimum management and sizing of combined heat and power, auxiliary boiler, absorption chiller, as well as transformer unit as the essential components of an SEH. It is difficult to address the requirements of SGs with most conventional load scheduling algorithms because they lack robustness and performance in complex environments. An evaluation of the benefits and costs of optimizing such parameters was carried out in this paper and the Reinforcement Learning (RL) algorithm is applied to solve the optimization problem. An individual user in a dynamic electrical market was examined as an SEH in support of the suggested approach. According to simulation outcomes, the suggested method is effective regarding time efficiencies and load variations. [ABSTRACT FROM AUTHOR]

Digital twins are able to bridge the physical and the virtual world, which is especially useful in industrial environments. One small, but rather essential, kind of digital twin is the so called virtual sensor model. This type of model is used to enhance or replace a physical sensor in industrial settings to reduce costs or enable information retrieval from inaccessible locations within a machine or process. The virtual sensor model is usually trained once, whereat only a predefined amount of information without any adaptation possibilities on the clients side is provided. As manufacturers want to provide the possibility of custom adaptations for their clients, the virtual sensor models require to incorporate adaptive features, which also have to handle incomplete data recordings, e.g. uncensored data. Traditional offline machine learning approaches are often insufficient for such adaptive requirements, therefore the usage of online learning approaches is gaining increased attention, to avoid high computational, storage and temporal costs. This paper covers the continued training of such adaptive virtual sensor models, focusing on the handling and integration of censored online data. Different approaches to tackle the problems of catastrophic forgetting in online learning and correction of censored data are presented as well as the handling of censored data in online learning environments. The experiments sections compares various scenarios with and without censored data using an industrial dataset and demonstrates the positive influence of different online learning approaches. [ABSTRACT FROM AUTHOR]

When long parts are machined in forged blanks, the variability of bulk residual stress (RS) fields leads to uncontrolled deformation after machining, requiring manual reshaping. An original hybrid digital twin of forged part is thus proposed to manage the bulk RS variability and reduce part distortion in machining. The behavior model of parts relies both on reduced models of thermomechanical simulations of the forging process variability, on-line measurements and machine learning from the previous parts deformations. Adaptive machining solutions can then be simulated for a rapid decision-making. The approach was validated on a series of aeronautic forged parts. [ABSTRACT FROM AUTHOR]

Data gathering related to biological parameters evolution using sensor networks associated to the patient, correlated with the analysis and data processing, together with a priori information and knowledge related with the patient, will allow developing new digital models for the characterization of healthcare state. By the help of algorithms for automated learning or neuromorphic devices, one can build a library for patients' Digital Twins based on its corresponding health state. In this papers authors present the main components of an integrated informatic platform which assure an efficient access for patients to various medical health services. Also, the paper presents a model for each patient health state using specific artificial intelligence techniques as a support system for every family doctor's decision and medical experts. [ABSTRACT FROM AUTHOR]

Recent neurological studies shows that emotions are tightly connected to the thinking and cognitive actions, being part of the decision-making process. Considering this, having a way to help decision making processes based on current emotion of the user or to consider the potential emotional impact if a decision is made, would be beneficial. This paper introduces a novel method for fusing multiple emotional signals, using a weighted average, where each weight value adapts to real time conditions, based on signal type, presence, and quality. In the context of a training station for manual operation, we implemented and tested separately several emotion detection methods, each based on a different signal acquired from audio, video, and galvanic skin response data streams. The final goal is to include the proposed method together with state of the art emotion detection machine learning algorithms as part of the digital twin training station for manual operation. [ABSTRACT FROM AUTHOR]

A new idea of machine learning-based technological process segmentation with the use of multi-sensor measurement is proposed in this article. The proposed segmentation of the machining process through appropriate measurement data modelling provides valuable insight that is necessary for technological parameters optimization or predictive maintenance. By combining multi-sensor industrial measurement and data science, this new solution is a more advanced and effective way of determining qualitative characteristics of the machining process that must be taken into account when developing smart analytical approaches, such as digital twins. An experimental measuring system consisting of accelerometers and current transducers is described. The system is implemented on an industrial CNC machine in order to assess operating conditions of the spindle and axis drives during the milling process. A novel method of detecting and segmenting the milling phases is proposed, involving data preprocessing and time-series signals data analysis to detect specific patterns or features that are indicative of each phase of the milling process. When applied in smart structures or digital twins, the proposed segmentation method provides similar information to that obtained by tomography imaging; therefore, the new method is called as virtual tomography. The developed phase segmentation method is of vital practical importance in terms of industrial implementation of technological process measurement and diagnostic systems. Especially as it can provide valuable information concerning elementary cutting zones and their influence on the process efficiency or influence of the composite structure layers machining on the tool wear, not available using hitherto known methods. [Display omitted] • Novel unsupervised technique identifies milling phases, enhancing tool SOH prediction. • Phase-specific feature analysis boosts predictive model accuracy in tool monitoring. • Feature analysis reveals key features impacting milling process and tool health. • Approach advances manufacturing efficiency through virtual tomography in smart structures. [ABSTRACT FROM AUTHOR]

• Efficient metallurgical operations are necessary for ecological sustainability. • Data-driven deep learning models capture intricate relationships among parameters. • Multivariate multistep time series forecasting provides insights for optimisation. • CNN outperforms LSTM and GRU in predicting gold concentrate grade six steps ahead. The escalating demand for environmental and social sustainability underscores the critical need for large industries such as mining and metallurgy to function optimally. Achieving optimal operation of a mineral processing plant requires timely access to information and rapid implementation of corrective actions. Essential information, such as current and future production, plays a pivotal role in enhancing process efficiency by facilitating adjustments in key aspects, including feed, control and operating variables. This study delves into the application of deep learning algorithms to forecast the gold concentrate grade of a flotation process half an hour in advance, a valuable tool for short-term decision-making, e.g., with regard to optimising the operation and process control. Multivariate time series data from a real gold processing plant was acquired through the process instrumentation and control system and augmented with simulated data at 5-minute intervals over 236 days. Surrogate models based on LSTM, GRU and CNN architectures were developed and analysed for predicting the gold grade one to six steps ahead. Evaluation of the testing dataset indicates that the CNN exhibits superior performance, achieving an average error reduction of 36 %, 45 % and 35 % for the performance metrics RMSE, MAE and MAPE respectively compared to the baseline model. These findings reveal the high potential of deep learning surrogate methods for accurately forecasting process outputs, enabling effective data-driven process control and optimisation strategies. [ABSTRACT FROM AUTHOR]

In forestry, colored spray paint is used for different purposes, such as marking trees that are chosen for the next harvest or that will be promoted by future silvicultural activities, or for the demarcation of skid/cable roads. Numerous studies have demonstrated the application of Terrestrial Laser Scanners (TLS) and Personal Laser Scanners (PLS) for the acquisition of tree parameters (diameters, heights, and tree positions) in a forest inventory context. However, no studies have included classification based on spectral information by applying colored markings to trees. When a laser scanner is combined with a camera, the color information can be mapped onto the laser point cloud, allowing for additional analysis of spectral information. In this study, we have tested the analysis of joint information from imagery and 3D point clouds in two different settings: (i) PLS point cloud data from a GeoSLAM ZEB Horizon were complemented with spectral information from images collected with a NCTech iSTAR Pulsar 360-degree camera, (ii) TLS point cloud data from a RIEGL VZ-400i were combined with imagery from a Nikon D850 digital single lens reflex (DSLR) camera with 14 mm fisheye lens. The major objective was to automatically classify trees that were marked with colored sprays automatically identify the numbers sprayed on the trees. The marked trees could be classified correctly with a balanced accuracy of 77.26% for PLS and 98.01% for the data collected with the TLS system using a support vector machine (SVM) model. The numbers written on the trees were classified from the TLS data using a YOLOv8 model. The accuracy of the digit classification reached up to 97.30%. In conclusion, it is possible to automatically detect marked trees and to automatically recognize the numbers spayed on these trees from colored point cloud data. However, accuracy strongly depends on the selected combination of scanner and camera. The findings of future research on this subject might differ with the ongoing development of PLS systems and could be enhanced by creating a large dataset of handwritten numbers collected using laser scanning systems. • Selecting marked trees is essential for using digital twins in forest management. • Colorized PLS and TLS point clouds enable automatic identification of marked trees. • Recognizing numbers sprayed on trees is possible from TLS data using a YOLOv8 model. • The performance of the classification is affected by scanner technology. • Reliable predictions of numbers require a large dataset collected by laser scanning. [ABSTRACT FROM AUTHOR]

Dynamic grasping is a crucial technology in the field of underwater robotics, playing an essential role in executing complex tasks. However, traditional control methods encounter challenges in achieving an efficient and stable dynamic grasping process due to the complexities and uncertainties of underwater environments. This paper introduces a novel black-box intelligent optimization algorithm named Social Learning with Actor–Critic (SLAC) for the dynamic grasping of underwater robots. The core architecture of SLAC is based on the integration of two key algorithms: Intelligent Social Learning (ISL) for intelligent optimization and Soft Actor–Critic (SAC) for reinforcement learning. ISL enhances SAC by supplying a larger number of transitions, whereas SAC improves ISL with more effective strategies. These algorithms interact synergistically, augmenting their respective strengths throughout the learning process. To evaluate SLAC's performance, a comparison is made with six state-of-the-art methods across eight continuous control benchmark cases. The results highlight SLAC's exceptional learning capability and performance benefits. Furthermore, virtual reality software for the underwater robot and a corresponding digital twin system have been developed. The SLAC algorithm is trained in the digital twin environment before its application in the actual underwater setting. Through interactive training and iterative learning, both simulated and experimental results demonstrate the robot's proficiency in achieving efficient and stable dynamic grasping, effectively adapting to various underwater environments' variations and complexities. • A Social Learning with Actor-Critic algorithm for black box robot control systems. • SLAC combines the advantages of intelligent optimization and reinforcement learning. • SLAC outperforms DDPG, SAC, PPO, EA, ISL, ERL in Mujoco benchmarks. • Develop underwater robot VR software and digital twin system platform. • Design grasping tasks and verify the superiority of SLAC in engineering simulations. [ABSTRACT FROM AUTHOR]

Irregular ocean waves contribute to random and non-linear hydrodynamic forces on marine and offshore platforms, in particular those made of slender bodies such as jack-ups. Keeping track of the structural fatigue, integrity, and reliability renders benefits to these platforms such as enabling predictive maintenance and risk-based decision support. While computational techniques are useful in providing insights to deepen our understanding of the physics involved, these are resource-intensive and not suited for predictive capabilities. Here we introduce an effective deep learning method based on Long Short Time Memory (LSTM) to predict unsteady hydrodynamic forces on jack-up legs, which are mainly governed by non-linear drag forces, as well as dynamic responses of the jack-up in terms of reaction forces and hull motion. The numerical OF-ABAQUS solver (one-way fluid-structure coupling) designed for jack-up by Li et al. (2022, 2023) is used to generate a database for the deep neural network, which takes in wave elevation time series as the input. A leaky non-linear rectification is used to trace the relationship between wave elevation (as the input) and hydrodynamic forces as well as structural responses (as the outputs). The LSTM model is trained using a stochastic gradient descent method, and the results are compared with the full-order numerical simulations. Once the hyper-parameters of the LSTM algorithm are identified, further tuning for each sea-state is not required. Instead, the same LSTM algorithm can be used for different sea-states. The predictions made with our LSTM model are real-time, 96,000 times faster than the full-order simulations, within a 6% error threshold, and use a negligible amount of central processing unit (CPU) power. This powerful tool can be used to obtain real-time predictions using computers on offshore platforms without high-performance computers inland. Further, the proposed LSTM-based method can be applied to create digital twins for jack-up platforms. [ABSTRACT FROM AUTHOR]

• Integrated digital twins Framework for revolutionizes defect diagnosis for pumps. • Domain adaptation boosts diagnostic model accuracy. • Promising potential for scalable industrial applications. Bearing defects in centrifugal pumps represent a prevalent source of equipment failure, often resulting in significant downtime and maintenance expenses. Deep learning algorithms can be used to detect defects. However, in the real world, there is always a scarcity of labeled data. To address this challenge, we propose a framework integrating digital twin technology with domain adaptation for accurate diagnosis of bearing defects. The proposed framework leverages the concept of digital twins to create a virtual representation of the pump bearing, enabling real-time monitoring and simulation of operating conditions. Domain adaptation techniques are then applied to transfer knowledge from synthetic data generated by the digital twin to the actual operating environment, overcoming the domain gap between synthetic and real-world data. The results highlight the potential of digital twin-assisted combined with domain adaptation techniques for enhancing predictive maintenance strategies in industrial applications. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) has undergone significant development over the past decades, resulting in vast amounts of data that carry valuable information. Numerous research studies have been conducted to extract insights from AM data and utilize it for optimizing various aspects such as the manufacturing process, supply chain, and real-time monitoring. Data integration into proposed digital twin frameworks and the application of machine learning techniques is expected to play pivotal roles in advancing AM in the future. In this paper, we provide an overview of machine learning and digital twin-assisted AM. On one hand, we discuss the research domain and highlight the machine-learning methods utilized in this field, including material analysis, design optimization, process parameter optimization, defect detection and monitoring, and sustainability. On the other hand, we examine the status of digital twin-assisted AM from the current research status to the technical approach and offer insights into future developments and perspectives in this area. This review paper aims to examine present research and development in the convergence of big data, machine learning, and digital twin-assisted AM. Although there are numerous review papers on machine learning for additive manufacturing and others on digital twins for AM, no existing paper has considered how these concepts are intrinsically connected and interrelated. Our paper is the first to integrate the three concepts big data, machine learning, and digital twins and propose a cohesive framework for how they can work together to improve the efficiency, accuracy, and sustainability of AM processes. By exploring latest advancements and applications within these domains, our objective is to emphasize the potential advantages and future possibilities associated with integration of these technologies in AM. • Explored how additive manufacturing evolution yields big data, leveraging ML and DT to optimize manufacturing. • Discussed the interconnection among big data, machine learning, and digital twins. • Examined ML's role in material analysis, design optimization, process optimization, defect detection, and sustainability. • Reviewed current developments for the application of digital twins to empower additive manufacturing. [ABSTRACT FROM AUTHOR]

Digital Twins (DT) are the real-time virtual representation of systems, communities, cities, or even human beings with the substantial potential to revolutionize post-disaster risk management efforts and achieve resilient communities against the adverse effects of disasters. However, this potential remains largely unrecognized and poorly understood in disaster risk management. This study explores current achievements, existing challenges, and the untapped potential of DT in disaster risk management, and accordingly, proposes an improved Digital twin-based post-disaster risk management framework. This paper employs a systematic literature review approach focusing on digital post-disaster risk management twinning (DPRMT) and smart early warning systems derived from two databases: Scopus and Web of Science. After a screening process with exclusion criteria, the final analysis synthesizes findings from a selected set of 96 papers. The results revealed that previous studies are not beyond only providing general statements about DT. There is a need for diverse data collection methods, considering demographic and financial aspects, understanding social dynamics, employing dynamic models, recognizing interconnected systems, and giving due attention to the often-neglected recovery phase. This study proposes a comprehensive DPRMT concept framework leveraging decision-makers with a holistic and efficient approach that offers real-time, detailed, and data-driven modeling solutions to achieve insights into disaster-affected areas and communities. It is also helpful to optimize response planning, resource allocation, and scenario testing by capturing the dynamic and complex human behaviors and understanding interconnected systems and entities that are often overlooked in previous disaster risk management studies. [ABSTRACT FROM AUTHOR]

Digital twin (DT)-driven intelligent fault diagnosis (IFD) has been a hot topic, which can support personalized monitoring of critical machinery. A central challenge is that diagnostic models using deep learning (DL) suffer from the problem of catastrophic forgetting if personalized faults occur in dynamic environments. To deal with this issue, this article presents a class-incremental learning method with multi-fidelity information fusion (MFIF-CIL) for the continuous diagnosis of key faults in rolling bearings. First, an effective bearing DT model is constructed to generate enough low-fidelity (LF) simulation data. Second, feature boosting is developed to fit the residuals with distribution drifts between old classes and new classes, which helps prevent the problem of catastrophic forgetting. Last, the MFIF module is proposed for multi-fidelity knowledge transfer and fusion to leverage LF simulation data to improve the class-incremental learning ability of feature boosting with limited high-fidelity (HF) physical data. The testing datasets consisting of the measured signals are utilized as testing datasets of optimal incremental neural networks for fault diagnosis. The proposed MFIF-CIL-1 (using 15 HF data and 100 LF data as exemplars) and MFIF-CIL-2 (using 20 HF data and 100 LF data as exemplars) obtain the average diagnostic accuracies of 96.87% and 98.10%, respectively. The MFIF-CIL-2 only uses 41.93% of the training time required by the joint training method. These satisfying results demonstrate that the MFIF-CIL can effectively diagnose different health conditions over time and provide a tradeoff between relatively low experimental costs and high accuracy. • A digital twin model is developed for the dynamic modeling of bearings. • Feature boosting mechanism is used to overcome catastrophic forgetting. • Multi-fidelity information fusion for reduction of the experimental costs. • One laboratory dataset is used to validate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Health monitoring of structures using ultrasonic guided waves is an evolving technology with potential applications in monitoring pipelines, civil bridges, and aircraft components. However, the sensitivity of guided waves to external parameters affects the reliability of monitoring systems based on them. These influencing factors and experimental related factors cannot be perfectly modeled, which give rise to the discrepancy between numerical simulations and experimental measurements. Therefore, it is important to address this inevitable discrepancy and generate close-to-experiment simulations. In this work, we present a deep learning-based Digital Twin framework containing multi-fidelity modeling to reduce the discrepancy between measurements and simulations and a deep generative model to generate close-to-experiment guided wave responses by harnessing the vital characteristics of the two sources. These realistic simulations (close to experiment) can then be used in assessing the reliability of health monitoring system by generating probability of detection curves. Furthermore, they can also be used for augmenting the training data for a machine learning algorithm. We use a measurement dataset corresponding to crack propagation and simulations to validate the proposed framework. The results show that the discrepancy is indeed reduced to a great extent, furthermore, we also show that this framework enables the computation of probability of detection from close-to-experiment data as a direct consequence of rapid generation of realistic simulations. • Structural health monitoring based on ultrasonic guided waves. • Discrepancy reduction between simulations and experiments. • A novel unifed deep neural network model blending simulations and experiments. • Enhanced ultrasonic guided waves signals generation. • Discrepancy quantification through phase and amplitude based misfit metrics. • Metamodel based computation of probability of detection. [ABSTRACT FROM AUTHOR]

The lubrication regimes of a laboratory scale journal bearing were analysed with wide band acoustic emission (AE) measurements. The analysis was supported by data-based clustering of AE data. Digital twin of the journal bearing was generated with Simpack multi-body simulation software to study opportunities for developing a hybrid methodology for more complex systems monitoring. The AE and data-based clustering approach can be effectively used to reveal fundamental lubrication modes, i.e., hydrodynamic (HL), mixed (ML) and boundary (BL) lubrication as a function of Hersey number, which can be evaluated in situ by utilizing digital twin. Besides AE the other parameters monitored were friction torque, bearing temperature, loading, sliding velocity and oil pressure. The materials used in the experiments were case-hardened 18CrNiMo7–6 steel and nitrided 42CrMo7 steel. The tests were lubricated with synthetic extreme-pressure gear oil (SGN 320) and the bearing temperature was kept constant during the tests. The bearing loading and sliding velocity during tests were varied in the wide range resulting in different lubrication situations. The acoustic emission signals power and frequency content was analysed, and essential features were extracted for data clustering. For lubrication regime change identification the parameters such as signal RMS and coefficient of variation (CV) proved to be important, while signal kurtosis showed to be the most sensitive in discovering anomalies. The high sensitivity requires data filtering to remove erroneous peaks and to reveal real trends more clearly. It is also interesting to notice the changes in AE frequency during changing to different lubrication regime. In literature different clustering and classification methods has been proposed and applied for journal bearing status identification. Here the selected unsupervised clustering method was the mean-shift clustering due to fact, that the lubrication regimes in the Stribeck curve form an inseparable continuum. The algorithm does not require specifying the number of clusters in advance, i.e., the clusters are determined by the algorithm with respect to the data. The results were compared to simulations with digital twin. i.e., by comparing simulated digital twin film thickness and measured AE kurtosis relative to measured Hersey number. It was concluded that digital twins can be utilized as virtual sensor for in situ detecting of lubrication regimes, if it is possible to calibrate the simulation with sensitive measurements, e.g., AE. It is obvious that simulations alone cannot predict suddenly appearing anomalies, such as impurities or surface fatigue failures. • Lubrication regimes in Stribeck curve can be detected with acoustic emission. • The kurtosis showed to be an important feature in detecting lubrication status. • Machine learning data clustering supports near real-time monitoring. • Digital twin can be used as virtual lubrication sensor if calibrated with AE. • Simulations alone cannot predict suddenly appearing anomalies. • With described hybrid approach the monitoring efficiency may be enhanced. [ABSTRACT FROM AUTHOR]

Digital twins belong to ten of the strategic technology trends according to the Gartner list from 2019, and have encountered a big expansion, especially with the introduction of Industry 4.0. Sport, on the other hand, has become a constant companion of the modern human suffering a lack of a healthy way of life. The application of digital twins in sport has brought dramatic changes not only in the domain of sport training, but also in managing athletes during competitions, searching for strategical solutions before and tactical solutions during the games by coaches. In this paper, the domain of digital twins in sport is reviewed based on papers which have emerged in this area. At first, the concept of a digital twin is discussed in general. Then, taxonomies of digital twins are appointed. According to these taxonomies, the collection of relevant papers is analyzed, and some real examples of digital twins are exposed. The review finishes with a discussion about how the digital twins affect changes in the modern sport disciplines, and what challenges and opportunities await the digital twins in the future. [ABSTRACT FROM AUTHOR]

The digital twin system of nuclear reactors is the foundation for the intelligent operation and maintenance of reactors and the visualization of operational data. Because of the current problem of low computational accuracy and lack of interpretability of deep learning algorithms for complex physical fields, this paper designs a deep learning and numerical analysis fusion algorithm based on a time series convolutional neural network algorithm, which can be used to solve the neutron diffusion spatiotemporal kinetics equation. The algorithm is based on convolutional neural network architecture, using finite volume method, constructing fixed parameter convolution kernel, and reconstructing loss function to replace convolutional neural network structure. This algorithm retains the convolutional neural network's structure and ensures that all steps have clear physical meaning. Finally, the algorithm logic and GPU acceleration are implemented on the Pytorch platform, and the algorithm's feasibility is verified using the simplified Tsinghua High Flux Reactor(THFR). The results show that the relative errors between the time series convolutional neural network and OpenMC in calculating the neutron flux density and the fission reaction rate are approximately within the range of 1% to 5%. The calculation speed of the time series convolutional neural network for neutron flux density is 1/20 of OpenMC, and the calculation speed of the expansion matrix is 1/8 of the NumPy library. Therefore, the time series convolutional neural network not only ensures the accuracy of calculation and improves the speed of operation, but also ensures the interpretability of the algorithm. In addition to being used to solve the neutron diffusion spatiotemporal kinetics equation, this algorithm is mainly used to develop the virtual physics engine of the digital twin system. Using this algorithm to implement the virtual reality method of the neutron field provides theoretical guidance and algorithm support for the development of the THFR digital twin system. [ABSTRACT FROM AUTHOR]

Real-time weighing plays a crucial role in various applications in the road infrastructure field, such as pavement design, pavement monitoring systems, and the development of digital twins. Innovative sensing technologies offer solutions to the limitations of traditional sensors, enhancing durability and cost-effectiveness. Current research on self-sensing technologies primarily focuses on material manufacturing, electrode embedding, and testing of piezoresistive properties. However, there is limited investigation of innovative methods for processing and analyzing electrical signals from self-sensing materials for load classification. The novelty of the present paper lies in the development of a machine learning-based load classifier using electrical data from laboratory self-sensing asphalt mixtures with carbon fibers (CFs). Specimens underwent repeated cyclic dynamic loads, and electrical signals were recorded and processed using a customized digital processing algorithm. Artificial Neural Network (ANN) and decision tree algorithms were employed to develop load classification models. Results indicate that the addition of CFs strengthens the asphalt mixture, converting it into a piezoresistive material with load-sensing capabilities. Conclusions show that while the machine learning algorithms performed satisfactorily, further research is required for optimization purposes. [Display omitted] • Carbon fibres transform asphalt mixtures into a self-sensing material. • Electromechanical laboratory tests were conducted. • Discrete Wavelet Transform (DWT) was employed for filtering data. • Different machine-learning algorithms were developed for load classification. [ABSTRACT FROM AUTHOR]

Artificial intelligence and its subfields, such as machine learning, robotics, optimisation, knowledge-based systems, reality capture and extended reality, have brought remarkable advancements and transformative changes to various industries, including the building deconstruction industry. Acknowledging AI's benefits for deconstruction, this paper aims to investigate AI applications within this domain. A systematic review of existing literature focused on AI applications for planning, implementation and post-implementation activities within the context of deconstruction was carried out. Furthermore, the challenges and opportunities of AI for deconstruction activities were identified and presented in this paper. By offering insights into AI's application for key deconstruction activities, this paper paves the way for realising AI's potential benefits for this sector. • Artificial intelligence, types, and subfields in deconstruction. • AI applications in planning, implementation, and post-implementation activities. • Challenges of adopting AI in the deconstruction industry. • Potential opportunities of AI in deconstruction. • Future studies like extended reality, digital twins, and generative AI. [ABSTRACT FROM AUTHOR]

• Physics-guided machine learning models were developed to predict thermal behaviors of advanced test reactors capsules. • Feature similarity measurement showed good predictive performance for the extrapolation cases. • An approach for data similarity enhancement and data recovery planning was applied to enhance the machine learning predictive capabilities. Instrumented experiments conducted at test reactors are essential to the deployment of new advanced reactor systems. Designing new experiments and generating data on specific reactor conditions require significant investments in terms of both time and cost. Finite element analysis software can be used to create high-fidelity models of experiment environments in order to support the actual experiments, but computation time remains a concern in terms of applying outcomes to real-time usage of data (e.g., a digital twin [DT]). The present research proposes a machine-learning (ML) aided approach to making temperature and displacement predictions based on the thickness of the outer gas gap on the experimental capsule used for in-pile demonstration of a novel new thermal conductivity probe in the Advanced Test Reactor (ATR). This capsule consisted of U10Zr fuel, a rodlet, sodium, and inner and outer capsules. Gas gaps existed between the fuel and the rodlet, and between the inner and the outer capsule. The learning data pertained to an experimental capsule's radial distributions of temperature and displacement, as obtained based on Abaqus and the physical features. For the first step of ML sequence, the temperature was predicted using three positional parameters. Next, the displacement was predicted using seven additional parameters. Each physical feature was normalized in order to be both nondimensional and standardized. The temperature and displacement predictions showed good agreement with the simulation results in all cases involving interpolation and extrapolation. Furthermore, data similarity enhancement increased the similarity between the training and the target data, thereby increasing the predictive accuracy of the ML models. In certain extrapolation cases involving limited original ML model accuracy, data similarity enhancement and data recovery was able to somewhat improve this accuracy. [ABSTRACT FROM AUTHOR]

• Combustion-based manufacturing needs innovative solutions to drastically reduce carbon emissions. • Digital twin technology can improve the efficiency and reduce emissions of industrial furnaces. • Digital twins can revolutionize all lifecycle phases of furnaces, from design optimization to online control. • This technology facilitates the transition of furnaces to zero-carbon fuels, aiding environmental sustainability. • It is crucial to develop standardized frameworks and enhance the reliability of digital twin models. The energy-intensive industry, heavily reliant on heat generation processes, faces the critical challenge of drastically reducing greenhouse gas emissions. This study reviews the potential of digital twin technology in decarbonizing combustion-dependent manufacturing processes. While primarily focusing on scholarly articles, our analysis may not cover all current industrial practices and digital twin implementations. This paper highlights challenges and opportunities in deploying practical digital twins for industrial furnaces within the Industry 4.0 framework. Digital twins, integrating real-time simulation models with predictive capabilities, aim to enhance industrial furnaces' design, operation, and maintenance by combining high-fidelity simulations with data-driven modelling techniques. The findings indicate that digital twins can facilitate the transition to furnace electrification and adopting zero-carbon fuels, significantly reducing emissions and optimizing overall furnace performance. However, challenges like model reliability and high upfront investments in IT and connectivity infrastructures limit their widespread adoption. Despite these limitations, ongoing technological advancements predict a rapid expansion of digital twin applications in industrial furnaces, making them indispensable for achieving decarbonization goals in energy-intensive industries. [ABSTRACT FROM AUTHOR]

This review article explores the potential and significance of digital twins (DTs) in advancing battery technology, specifically in electric vehicles (EVs). Due to their ability to accurately predict, diagnose, and enhance energy systems, DTs offer a transformative solution for addressing environmental concerns and improving energy storage capabilities. Moreover, DTs hold promise in facilitating vehicle-to-grid (V2G) integration and testing autonomous driving systems, while robust cybersecurity measures will be essential to protect sensitive data. The applications of DTs in estimating state of charge (SOC) and state of health (SOH) parameters demonstrate their effectiveness in optimizing battery performance. In addition to exploring the application of artificial intelligence (AI) and machine learning models for improving battery performance while highlighting real-world case examples, the study also highlights how digital twin (DT) technology can enhance battery design, increase longevity, and ensure safety. Furthermore, this study discusses the challenges of implementing DTs for battery packs, and the potential applications of this technology in future directions are discussed. In conclusion, DTs are set to revolutionize the future of electric transportation, promoting sustainability and efficiency in the EV ecosystem. • Explores how digital twin technology can advance battery technology in electric vehicles (EVs). • The paper also highlights applications in V2G integration and autonomous driving systems, while emphasizing cybersecurity. • Overall, digital twins offer promising solutions for sustainable and efficient EVs. [ABSTRACT FROM AUTHOR]

Large volumes of 3D parametric datasets, such as building information modeling (BIM), are the foundation for developing and applying smart city and digital twin technologies. Those datasets are also considered valuable tools for efficiently managing rebuilt structures during the operation and maintenance stages. Nevertheless, current approaches developed for the scan-to-BIM process rely on manual or semi-automatic procedures and insufficiently leverage semantic data in point clouds. These methods struggle to accurately represent large-scale indoor complex layouts and extract details from irregular-shaped unstructured elements, causing inefficiencies in BIM model generation. To address these issues, we propose an innovative scan-to-BIM framework based on deep learning algorithms and raw point cloud data, enabling the automatic generation of 3D models for both structured and unstructured indoor elements. Initially, we propose an enhanced deep learning neural network to improve the point clouds' semantic segmentation accuracy. Subsequently, an efficient workflow is developed to reconstruct 3D building models of structured indoor scenes. The proposed workflow can reconstruct large-scale data with multiple room layouts of Manhattan or non-Manhattan structures and reconstruct 3D models automatically by using a BIM parametric algorithm implemented in Revit software. Moreover, we introduce a robust method for unstructured elements to automatically generate corresponding 3D BIM models, even when the incorporating semantic information is incomplete. The proposed approach was evaluated on synthetic and real data for different scales and complexities of indoor scenes. The results of the experiments demonstrate that the improved model significantly enhances the overall semantic segmentation accuracy compared to the baseline models. The proposed scan-to-BIM framework is efficient for indoor element 3D reconstruction, achieving precision, recall, and F-score values ranging from 96% to 99%. The generated BIM models are competitive with traditional methods regarding model completeness and geometric accuracy. • We propose an innovative scan-to-BIM framework based on deep learning algorithms: • We propose an enhanced deep-learning neural network to improve the point clouds' semantic segmentation accuracy. • A novel and efficient workflow is developed to reconstruct 3D building models of structured indoor scenes. It can reconstruct large-scale data with multiple room layouts in 3D model automatically by using a BIM parametric • For unstructured elements, we propose a robust method to automatically generate 3D BIM models, even when the semantic information is incomplete. [ABSTRACT FROM AUTHOR]

The increasing popularity of digital twins, alongside the rapid evolution of connectivity driven by the Internet of Things, highlights their potential to greatly aid in the development of smart cities. Digital twins are employed more commonly as smart cities grow and societies become more interconnected. With the growing need for this technology, there is a pressing demand for the automatic captioning of security events from the videos collected from these models. This is needed as Dtwin models generate a lot of data that makes it difficult to caption them manually. This is required for extracting rich and meaningful higher-level interpretations from images and videos. Current models often lack in-depth insights into these complex urban systems. Additionally, there is a need for a model that can interpret and explain images and videos effectively, leveraging a combination of machine learning and knowledge graph approaches. Therefore, in this paper, we developed the Digital Twin for the buildings and road network of the TEC (Tecnologico De Monterrey) district region and additionally developed the Knowledge Graph models for emulating security events with dense video captioning. This is done by designing an AI-based TEC District Digital Twin for emulating security events by leveraging knowledge graph. The proposed approach provides data and insights about the district's operations and security. This initiative will help district planners and managers to make better decisions by analyzing the real-time data. This is supposed to contribute to increased effectiveness of district services, transparency, and an efficient infrastructure. [ABSTRACT FROM AUTHOR]

Artificial intelligence and digital twins have become more popular in recent years and have seen usage across different application domains for various scenarios. This study reviews the literature at the intersection of the two fields, where digital twins integrate an artificial intelligence component. We follow a systematic literature review approach, analyzing a total of 149 related studies. In the assessed literature, a variety of problems are approached with an artificial intelligence-integrated digital twin, demonstrating its applicability across different fields. Our findings indicate that there is a lack of in-depth modeling approaches regarding the digital twin, while many articles focus on the implementation and testing of the artificial intelligence component. The majority of publications do not demonstrate a virtual-to-physical connection between the digital twin and the real-world system. Further, only a small portion of studies base their digital twin on real-time data from a physical system, implementing a physical-to-virtual connection. [ABSTRACT FROM AUTHOR]

Neural Operator Networks (ONets) represent a novel advancement in machine learning algorithms, offering a robust and generalizable alternative for approximating partial differential equations (PDEs) solutions. Unlike traditional Neural Networks (NN), which directly approximate functions, ONets specialize in approximating mathematical operators, enhancing their efficacy in addressing complex PDEs.In this work, we evaluate the capabilities of Deep Operator Networks (DeepONets), an ONets implementation using a branch–trunk architecture. Three test cases are studied: a system of ODEs, a general diffusion system, and the convection–diffusion Burgers' equation. It is demonstrated that DeepONets can accurately learn the solution operators, achieving prediction accuracy (R 2) scores above 0.96 for the ODE and diffusion problems over the observed domain while achieving zero-shot (without retraining) capability. More importantly, when evaluated on unseen scenarios (zero-shot feature), the trained models exhibit excellent generalization ability. This underscores ONets' vital niche for surrogate modeling and digital twin development across physical systems. While convection–diffusion poses a greater challenge, the results confirm the promise of ONets and motivate further enhancements to the DeepONet algorithm. This work represents an important step towards unlocking the potential of digital twins through robust and generalizable surrogates. [ABSTRACT FROM AUTHOR]

Building environmental assessment (BEA) is critical to improving sustainability. However, the BEA process is inefficient, costly, and often inaccurate. Because automation has the potential to enhance the efficiency and accuracy of the BEA process, studies have focused on automating BEA (ABEA). Updated until now, a comprehensive analysis of prevailing literature on ABEA remains absent. This study conducts the first comprehensive systematic analysis appraising the state-of-the-art of research on ABEA. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guided to systematically analyse 91 relevant studies. Results uncover that only 29.7% of BEA systems worldwide have automated their processes, with the US LEED residing at the vanguard of automation efforts. The New Buildings scheme was mostly focused on, while largely ignoring other schemes, e.g., Existing Buildings. Five key digital approaches to ABEA were revealed, namely building information modelling (BIM) and plug-in software, BIM-ontology, data mining and machine learning, cloud-BIM, and digital twin-based approaches. Based on identified gaps, future research directions are proposed, specifically: using data mining and machine learning models for ABEA; development of a holistic cloud-based approach for real-time BEA; and digital twin for dynamic BEA. This study generates a deeper understanding of ABEA and its theoretical implications, such as major constructs and emerging perspectives, constitute a basis for holistic, and innovation in, BEA. • This study presents the first comprehensive systematic analysis appraising the state-of-the-art of research on ABEA. • This study reveals focused and unfocused BEA systems and their schemes for ABEA. • Five key digital approaches to ABEA include BIM and plug-in software, BIM-ontology, data mining and machine learning, cloud-based, and digital twin-based approaches. • From the major construct, emerging perspectives and gaps identified, potential future research directions related to ABEA are presented. [ABSTRACT FROM AUTHOR]

Due to the growing rate of energy consumption, it is necessary to develop frameworks for enhancing ship energy efficiency. This paper proposes a solution for this issue by introducing a digital twin framework for quantifying ship performance. For this purpose, extensive low-level clustering is performed using Gaussian Mixture Models (GMM) with the Expectation Maximization algorithm on a dataset of a selected vessel to detect the vessel's most frequent operating regions. Then, a regression analysis is performed in each operating region, to identify their shapes using Singular Value Decomposition (SVD). The results of SVD make the basis for model development in digital twin applications. For this reason, a low-level clustering is performed so that a more accurate model can be developed in future. Moreover, based on the resulting cluster analysis, an energy efficiency index is developed, and the energy efficiency of each cluster has been evaluated to identify the most efficient operating condition. Hence, the main contribution of this research is to develop a digital twin framework of a marine engine which can be utilized for green ship operations. The same contribution can facilitate the shipping industry to meet the International Maritime Organization energy efficiency requirements. • Introducing a digital twin framework for quantifying ship performance. • Capturing 7 operating regions of a selected vessel using GMM-EM approach. • Finding the most frequent operating region of the selected vessel. • Utilizing two different methods to find the proper number of clusters for GMM-EM. • Using SVD to find the relationship between variables and shape of each operating region. • Defining an Energy Efficiency Index to find the most energy efficient operating region. [ABSTRACT FROM AUTHOR]

The European Commission (EC) has launched the European Green Deal communication, setting out the path for a fundamental transformation of Europe. Key element in this policy is a fully sustainable food system outlined in the farm-to-fork strategy. Such strategy requires a systems approach in which all aspects related to the production and consumption of sufficient and healthy food are considered, including economic, environmental (climate, ecosystems) and social aspects. Here, we present the systems approach concept for food production, following the farm-to-fork principle as embraced by the EC, and elaborate on how digitalisation and Artificial Intelligence (AI) can solve the challenges that a sustainable food system imposes. We present a number of research and innovation challenges and illustrate these by some specific examples. It is concluded that AI and digitalisation show great potential to support the transition towards a sustainable food system. This development will impact the roles and interactions of the actors in the entire value chain from farmers to consumers. Policy recommendations are made for a successful future implementation of AI in sustainable food production. • System approach is needed to achieve sustainable food systems. • AI and digitalisation are key to the transition towards sustainable food systems. • Data availability and use is important for actors in all stages from farm to fork. • Policy recommendations for a successful AI implementation in food systems. [ABSTRACT FROM AUTHOR]

A wide variety of computational models covering statistical, mechanistic, and machine learning (locked and adaptive) methods are explored for use in biopharmaceutical manufacturing. Limited discussion exists on how to establish the credibility of a computational model for application in biopharmaceutical manufacturing. In this work, we tried to use the American Society of Mechanical Engineers (ASME) Verification and Validation 40 (V&V 40) standard and FDA proposed AI/ML model life cycle management framework for Software as a Medical Device (SaMD) in biopharmaceutical manufacturing use cases, by applying to a set of curated hypothetical examples. We discussed the need for standardized frameworks to facilitate consistent decision making to enable efficient adoption of computational models in biopharmaceutical manufacturing and alignment of existing good practices with existing frameworks. In the study of our examples, we anticipate existing frameworks like V&V 40 can be adopted. [ABSTRACT FROM AUTHOR]

Digital twin ushers in growth as one cutting-edge technology that enables high-precision, informative and real-time interaction of advanced composites, influencing the paradigm of composite analysis and design in aerospace, automotive, intelligent electronics and other fields. The online and fine evolution of digital twins at scale face challenges due to creating scalable predictions, updates, and controls with coupled information in workflows. In this work, an interactive digital twin methodology for complex composite structures (CCSDT) based on machine learning is introduced. To demonstrate the framework's feasibility and applicability, a hybrid architecture comprising hierarchical deep neural networks (H-DNNs), statistical inference and cross-scale physical constraints is proposed considering the fabric rubber composites (FRC) in aerospace field. The framework predicts 3D displacement and stress fields directly from sensing features and can incorporate dynamic updating and evaluation of computational models into data assimilation. Real-time prediction and uncertainty quantification are verified through synthetic and experimental data, and the capability of CCSDT in perception and decision is demonstrated by a case of cruise state monitoring. The comparison between the measured strain field and the post-processing predicted strain field shows the extensibility of the direct prediction results. These results provide guidance for the development of composite digital twins, stimulating the potential for cost-effective and efficient digital twin services. [Display omitted] [ABSTRACT FROM AUTHOR]

The digital twinning process is essential for transferring real-world objects to the Metaverse by creating accurate digital versions, known as digital twins. However, complex systems pose challenges in this process. With the increasing utilization of microwave components and circuits in telecommunication systems such as IoT, 5 G, and 6 G, the need for digital twins of these components arises. Nevertheless, high-frequency components exhibit intricate behavior, requiring advanced modeling techniques. Artificial intelligence (AI) provides a powerful tool for enhancing the reliability and accuracy of estimated models in such cases. In this study, a microstrip lowpass filter (LPF) is designed, fabricated, and measured as the physical twin. An intelligent digital twinning approach is employed using a machine learning method based on an adaptive neuro-fuzzy inference system (ANFIS), trained by a subtractive clustering algorithm. The resulting digital twin of the LPF proves valuable for communication networks and IoT applications. Moreover, this research showcases the applicability and accessibility of machine learning in creating digital twins of electromagnetic components for communication cyber-physical systems (CPSs) and the Metaverse. Furthermore, the proposed method exhibits adaptability to various passive and active electrical or electronic circuits. By harnessing the potential of AI and digital twinning, this study presents a robust and accurate approach for modeling and analyzing complex circuits, specifically in the context of communication systems and their integration into the Metaverse. The findings highlight the advantages of an intelligent digital twinning approach and its potential for advancing various domains involving complex circuitry. • Machine learning for accurate digital twins in telecom & Metaverse. • Microstrip filter case study shows IoT & network benefits. • Machine learning enhances electromagnetic twins for CPS & Metaverse. • AI-driven circuit modeling & analysis advances in telecom. • Robust digital twin solutions for IoT & future 5G/6G tech. [ABSTRACT FROM AUTHOR]