A large number of anomalous extension twins,with low or even negative twinning Schmid factors,were found to nucleate and grow in a strongly textured Mg-1Al alloy during tensile deformation along the extruded direction...A large number of anomalous extension twins,with low or even negative twinning Schmid factors,were found to nucleate and grow in a strongly textured Mg-1Al alloy during tensile deformation along the extruded direction.The deformation mechanisms responsible for this behaviour were investigated through in-situ electron back-scattered diffraction,grain reference orientation deviation,and slip trace-modified lattice rotation.It was found that anomalous extension twins nucleated mainly at the onset of plastic deformation at or near grain boundary triple junctions.They were associated with the severe strain incompatibility between neighbour grains as a result from the differentbasal slip-induced lattice rotations.Moreover,the anomalous twins were able to grow with the applied strain due to the continuous activation ofbasal slip in different neighbour grains,which enhanced the strain incompatibility.These results reveal the complexity of the deformation mechanisms in Mg alloys at the local level when deformed along hard orientations.展开更多
Against the backdrop of continuous development in the field of education,universities are encouraged to innovate their talent cultivation systems and objectives.The deep integration of industry and education has emerg...Against the backdrop of continuous development in the field of education,universities are encouraged to innovate their talent cultivation systems and objectives.The deep integration of industry and education has emerged as an effective strategy,aligning with the basic requirements of the new engineering education initiative and exerting a positive impact on socioeconomic development.However,an analysis of the current state of industry-education integration in universities reveals several issues that require optimization,affecting the ultimate effectiveness of integration.To optimize this phenomenon and achieve high-quality development,universities need to further explore the construction of a deep integration model of industry and education,adhering to corresponding principles to form a comprehensive system.On this basis,pathways for deep industry-education integration can be summarized.展开更多
In this work,Digital Twins based on Neural Networks for the steady state production of styrene were generated.Thus,both the Aspen Technology AI Model Builder(alternative 1)and a homemade MS Excel VBA code connected to...In this work,Digital Twins based on Neural Networks for the steady state production of styrene were generated.Thus,both the Aspen Technology AI Model Builder(alternative 1)and a homemade MS Excel VBA code connected to Aspen HYSYS and Aspen Plus(alternative 2)were used with this same aim.The raw data used for generating the Digital Twins were obtained from process simulations using Aspen HYSYS and/or Aspen Plus,which were connected through a recycle-like stream via automation for solving the entire simulation flowsheet.Aspen HYSYS was used for solving the pre-heating,reaction,and stabilization sections of the process whereas Aspen Plus ensured the computing of the separation and purification columns.Both alternatives led to an excellent prediction showing the capability of creating Digital Twins from and for process simulation.展开更多
In this work,an as-rolled AZ31 square bar with c-axis//ND(normal direction)texture was used.Side-rolling and reciprocating torsion were performed to treat the bar.Microstructure evolution and tensile-compressive prope...In this work,an as-rolled AZ31 square bar with c-axis//ND(normal direction)texture was used.Side-rolling and reciprocating torsion were performed to treat the bar.Microstructure evolution and tensile-compressive properties were investigated in detail.Initial rolled AZ31 bar exhibits a large yield asymmetry along the rolling direction(RD).Reciprocating torsion can generate extension twins to introduce twin boundaries and twin-texture.The twin structure can reduce yield asymmetry.However,only limited regions in the rolled AZ31 bar can be twinned during torsion.Pre-side-rolling along the transverse direction(TD)can generate two texture components(c-axis//TD texture and c-axis//ND texture)by introducing profuse{10–12}twins.Such dual texture components help increase the regions which are favorable for twinning during torsion.Finally,combining side-rolling and reciprocating torsion generates hybrid{10–12}twins structure on the entire cross-section,resulting in a remarkably low yield asymmetry.The relevant mechanisms were discussed in detail.展开更多
A combined experimental and computational analysis is performed to investigate the less commonly studied embryo-to-lamella transition of deformation twins in magnesium. This work aims to understand the structural vari...A combined experimental and computational analysis is performed to investigate the less commonly studied embryo-to-lamella transition of deformation twins in magnesium. This work aims to understand the structural variables controlling the embryo-to-lamella transition from grain boundaries. Statistical analysis of hundreds of early-stage twins in the lightly deformed microstructure reveals a prevailing wedge shape,with a much thicker base along the grain boundary(GB) where they originate and a thinner tip terminating in the crystal. The analysis also shows that the GB base is super thick and identifies a minimum GB twin thickness among all early-stage twins that is about one micron. A crystal plasticity-based full-field model is employed to calculate the driving forces to migrate the boundary of a three-dimensional GB twin embryo. The stress analysis, considering a full range of embryo shapes and neighboring grain orientations, indicate that the twin embryo is most likely going to form a wedge shape when it first propagates. The calculations predict that the thickness of the embryo at the GB needs to be significantly larger than its length into the crystal in order to propagate into the crystal. The analysis finds that the more aligned the twin embryo variant is with basal slip in the neighboring grain, the thinner the twin embryo needed for propagation.展开更多
Digital twins for wide-areas(DT-WA)can model and predict the physical world with high fidelity by incorporating an artificial intelligence(AI)model.However,the AI model requires an energy-consuming updating process to...Digital twins for wide-areas(DT-WA)can model and predict the physical world with high fidelity by incorporating an artificial intelligence(AI)model.However,the AI model requires an energy-consuming updating process to keep pace with the dynamic environment,where studies are still in infancy.To reduce the updating energy,this paper proposes a distributed edge cooperation and data collection scheme.The AI model is partitioned into multiple sub-models deployed on different edge servers(ESs)co-located with access points across wide-area,to update distributively using local sensor data.To reduce the updating energy,ESs can choose to become either updating helpers or recipients of their neighboring ESs,based on sensor quantities and basic updating convergencies.Helpers would share their updated sub-model parameters with neighboring recipients,so as to reduce the latter updating workload.To minimize system energy under updating convergency and latency constraints,we further propose an algorithm to let ESs distributively optimize their cooperation identities,collect sensor data,and allocate wireless and computing resources.It comprises several constraint-release approaches,where two child optimization problems are solved,and designs a largescale multi-agent deep reinforcement learning algorithm.Simulation shows that the proposed scheme can efficiently reduce updating energy compared with the baselines.展开更多
In order to improve the comprehensive defense capability of data security in digital twins(DTs),an information security interaction architecture is proposed in this paper to solve the inadequacy of data protection and...In order to improve the comprehensive defense capability of data security in digital twins(DTs),an information security interaction architecture is proposed in this paper to solve the inadequacy of data protection and transmission mechanism at present.Firstly,based on the advanced encryption standard(AES)encryption,we use the keystore to expand the traditional key,and use the digital pointer to avoid the key transmission in a wireless channel.Secondly,the identity authentication technology is adopted to ensure the data integrity,and an automatic retransmission mechanism is added for the endogenous properties of the wireless channel.Finally,the software defined radio(SDR)platform composed of universal software radio peripheral(USRP)and GNU radio is used to simulate the data interaction between the physical entity and the virtual entity.The numerical results show that the DTs architecture can guarantee the encrypted data transmitted completely and decrypted accurately with high efficiency and reliability,thus providing a basis for intelligent and secure information interaction for DTs in the future.展开更多
To understand the current application and development of 3D modeling in Digital Twins(DTs),abundant literatures on DTs and 3D modeling are investigated by means of literature review.The transition process from 3D mode...To understand the current application and development of 3D modeling in Digital Twins(DTs),abundant literatures on DTs and 3D modeling are investigated by means of literature review.The transition process from 3D modeling to DTs modeling is analyzed,as well as the current application of DTs modeling in various industries.The application of 3D DTs modeling in theelds of smartmanufacturing,smart ecology,smart transportation,and smart buildings in smart cities is analyzed in detail,and the current limitations are summarized.It is found that the 3D modeling technology in DTs has broad prospects for development and has a huge impact on all walks of life and even human lifestyles.At the same time,the development of DTs modeling relies on the development and support capabilities of mature technologies such as Big Data,Internet of Things,Cloud Computing,Articial Intelligence,and game technology.Therefore,although some results have been achieved,there are still limitations.This work aims to provide a good theoretical support for the further development of 3D DTs modeling.展开更多
At present,the interpretation of regional economic development(RED)has changed from a simple evaluation of economic growth to a focus on economic growth and the optimization of economic structure,the improvement of ec...At present,the interpretation of regional economic development(RED)has changed from a simple evaluation of economic growth to a focus on economic growth and the optimization of economic structure,the improvement of economic relations,and the change of institutional innovation.This article uses the RED trend as the research object and constructs the RED index to conduct the theoretical analysis.Then this paper uses the attention mechanism based on digital twins and the time series network model to verify the actual data.Finally,the regional economy is predicted according to the theoretical model.The specific research work mainly includes the following aspects:1)This paper introduced the development status of research on time series networks and economic forecasting at home and abroad.2)This paper introduces the basic principles and structures of long and short-term memory(LSTM)and convolutional neural network(CNN),constructs an improved CNN-LSTM model combined with the attention mechanism,and then constructs a regional economic prediction index system.3)The best parameters of the model are selected through experiments,and the trained model is used for simulation experiment prediction.The results show that the CNN-LSTM model based on the attentionmechanism proposed in this paper has high accuracy in predicting regional economies.展开更多
{1012¯}twins were introduced into the magnesium(Mg)plate AZ31 via pre-rolling along its transverse direction.The plates,both with and without the pre-induced{1012¯}twins,were subjected to uniaxial tension al...{1012¯}twins were introduced into the magnesium(Mg)plate AZ31 via pre-rolling along its transverse direction.The plates,both with and without the pre-induced{1012¯}twins,were subjected to uniaxial tension along different directions.Using crystal plasticity modeling,we found that the strengthening effect of the pre-induced{1012¯}twins on the macroscopic flow stress primarily arised from the increased slip resistance caused by the boundaries,rather than the orientation hardening due to the twinning reorientation(although the latter did make its contribution in some specific loading directions).Besides,the pre-existing{1012¯}twins were found,by both experiments and simulation,to promote the activity of prismatic and pyramidal<c+a>in the parent matrix of the material.Further analysis showed that the enhanced non-basal slip activity is related to the{1012¯}twin boundaries’low micro Hall-Petch slope ratios of non-basal slips to basal slip.With the critical resolved shear stress(CRSS)obtained from crystal plasticity modeling and the orientation data from EBSD,a probability-based slip transfer model was proposed.The model predicts higher slip transfer probabilities and thus lower strain concentration tendencies at{1012¯}twin boundaries than that at grain boundaries,which agrees with the experimental observation that the strain localization was primarily associated with the latter.The present findings are helpful scientifically,in deepening our understanding of how the pre-induced{1012¯}twins affect the strength and slip activity of Mg alloys,and technologically,in guiding the design of the pre-strain protocol of Mg alloys.展开更多
Despite advances in intelligent medical care,difficulties remain.Due to its complicated governance,designing,planning,improving,and managing the cardiac system remains difficult.Oversight,including intelligent monitor...Despite advances in intelligent medical care,difficulties remain.Due to its complicated governance,designing,planning,improving,and managing the cardiac system remains difficult.Oversight,including intelligent monitoring,feedback systems,and management practises,is unsuccessful.Current platforms cannot deliver lifelong personal health management services.Insufficient accuracy in patient crisis warning programmes.No frequent,direct interaction between healthcare workers and patients is visible.Physical medical systems and intelligent information systems are not integrated.This study introduces the Advanced Cardiac Twin(ACT)model integrated with Artificial Neural Network(ANN)to handle real-time monitoring,decision-making,and crisis prediction.THINGSPEAK is used to create an IoT platform that accepts patient sensor data.Importing these data sets into MATLAB allows display and analysis.A myocardial ischemia research examined Health Condition Tracking’s(HCT’s)potential.In the case study,75%of the training sets(Xt),15%of the verified data,and 10%of the test data were used.Training set feature values(Xt)were given with the data.Training,Validation,and Testing accuracy rates were 99.9%,99.9%,and 99.9%,respectively.General research accuracy was 99.9%.The proposed HCT system and Artificial Neural Network(ANN)model gather historical and real-time data to manage and anticipate cardiac issues.展开更多
Digital twins have emerged as a promising technology for maintenance applications,enabling organizations to simulate and monitor physical assets to improve their performance.In Operation and Maintenance(O&M),digit...Digital twins have emerged as a promising technology for maintenance applications,enabling organizations to simulate and monitor physical assets to improve their performance.In Operation and Maintenance(O&M),digital twin facilitates the diagnosis and prognosis of critical assets,forming the basis for smart maintenance planning and reducing downtime.However,there is a lack of standardized approaches for the qualifications of digital twins in maintenance,leading to low trustworthiness and limiting its application.This paper proposes a novel framework for the qualifications of digital twins in maintenance based on five pillars,namely fidelity,smartness,timeliness,integration,and standard compliance.We demonstrate the effectiveness of the framework through two case studies,showing how it can be implemented on digital twins for preventive maintenance and condition-based maintenance.Our proposed framework can help organizations across different industrial domains develop and implement digital twins in maintenance more effectively and efficiently,leading to significant benefits in terms of cost reduction,performance improvement,and sustainability.展开更多
Backgrounds This work emphasizes the current research status of the urban Digital Twins to establish an intelligent spatiotemporal framework.A Geospatial Artificial Intelligent(GeoAI)system is developed based on the G...Backgrounds This work emphasizes the current research status of the urban Digital Twins to establish an intelligent spatiotemporal framework.A Geospatial Artificial Intelligent(GeoAI)system is developed based on the Geographic Information System and Artificial Intelligence.It integrates multi-video technology and Virtual City in urban Digital Twins.Methods Besides,an improved small object detection model is proposed:YOLOv5-Pyramid,and Siamese network video tracking models,namely MPSiam and FSSiamese,are established.Finally,an experimental platform is built to verify the georeferencing correction scheme of video images.Result The MultiplyAccumulate value of MPSiam is 0.5B,and that of ResNet50-Siam is 4.5B.Besides,the model is compressed by 4.8times.The inference speed has increased by 3.3 times,reaching 83 Frames Per Second.3%of the Average Expectation Overlap is lost.Therefore,the urban Digital Twins-oriented GeoAI framework established here has excellent performance for video georeferencing and target detection problems.展开更多
The concept of community is of great significance in guiding the innovation of the mechanism of industry-education integration,which can promote the integration of industry-education integration from"integration&...The concept of community is of great significance in guiding the innovation of the mechanism of industry-education integration,which can promote the integration of industry-education integration from"integration"to real"integration".We summarize the current situation of the development of industry-teaching integration mode through research,point out the"four deviations"in the development of industry-teaching integration,analyze the causes of deviations,and put forward the research strategy of"four synergistic"innovation mechanism for industry-teaching integration based on the concept of community,i.e.,synergistic development of community planning It proposes the research strategy of"four synergies"innovation mechanism based on the concept of community,namely the synergy of community planning and development,the synergy of community governance concept,the synergy of community multi-party educating mechanism,and the synergy of community fusion effect system,so as to establish collaborative ties,build a new form of cooperation concepts,safeguard the docking of talent supply and demand,and enhance the effect of integration of industry and education.展开更多
In this study, a three dimensional(3D) numerical model of six-degrees-of-freedom(6DOF) is applied to simulate the water entries of twin spheres side-by-side at different lateral distances and time intervals.The turbul...In this study, a three dimensional(3D) numerical model of six-degrees-of-freedom(6DOF) is applied to simulate the water entries of twin spheres side-by-side at different lateral distances and time intervals.The turbulence structure is described using the shear-stress transport k-ω(SST k-ω) model, and the volume of fluid(VOF) method is used to track the complex air-liquid interface. The motion of spheres during water entry is simulated using an independent overset grid. The numerical model is verified by comparing the cavity evolution results from simulations and experiments. Numerical results reveal that the time interval between the twin water entries evidently affects cavity expansion and contraction behaviors in the radial direction. However, this influence is significantly weakened by increasing the lateral distance between the two spheres. In synchronous water entries, pressure is reduced on the midline of two cavities during surface closure, which is directly related to the cavity volume. The evolution of vortexes inside the two cavities is analyzed using a velocity vector field, which is affected by the lateral distance and time interval of water entries.展开更多
The mechanical behavior and microstructural evolution of an Fe-30Mn-3Al-3Si twinninginduced plasticity(TWIP)steel processed using warm forging was investigated.It is found that steel processed via warm forging improve...The mechanical behavior and microstructural evolution of an Fe-30Mn-3Al-3Si twinninginduced plasticity(TWIP)steel processed using warm forging was investigated.It is found that steel processed via warm forging improves comprehensive mechanical properties compared to the TWIP steel processed via cold rolling,with a high tensile strength(R_(m))of 793 MPa,a yield strength(R_(P))of 682 MPa,an extremely large R_(P)/R_(m)ratio as high as 0.86 as well as an excellent elongation rate of 46.8%.The microstructure observation demonstrates that steel processed by warm forging consists of large and elongated grains together with fine,equiaxed grains.Complicated micro-defect configurations were also observed within the steel,including dense dislocation networks and a few coarse deformation twins.As the plastic deformation proceeds,the densities of dislocations and deformation twins significantly increase.Moreover,a great number of slip lines could be observed in the elongated grains.These findings reveal that a much more dramatic interaction between microstructural defect and dislocations glide takes place in the forging sample,wherein the fine and equiaxed grains propagated dislocations more rapidly,together with initial defect configurations,are responsible for enhanced strength properties.Meanwhile,larger,elongated grains with more prevalently activated deformation twins result in high plasticity.展开更多
The construction of a municipal industry-education consortium is one of the important measures for the“one body,two wings,and five key points”reform of China’s modern vocational education system in the new era.It i...The construction of a municipal industry-education consortium is one of the important measures for the“one body,two wings,and five key points”reform of China’s modern vocational education system in the new era.It is of great significance for the integrated promotion of the three major national strategies of education,technology,and talent.Exploring the construction path of municipal industry-education consortia from the perspective of“four-chain integration”is essential for improving the quality of vocational education talents,comprehensively promoting local economic and social development,and serving the national strategy of revitalizing the country through science and education.The new generation of information technology industry-education consortium in Chengdu actively explores new paths of industry-education integration,science-education integration,and vocational-education integration.It has formed a“park+alliance”to establish a diversified collaborative construction and management mechanism,a“professional+industry”school-enterprise cooperation to promote industrial transformation and upgrading,a“teaching+research and development”to build an industry-university research innovation platform to empower high-quality development,and a“cultivation+employment”to explore a matrix style talent cultivation model,thus promoting regional governments,industries enterprises,and higher education institutions.Fully leveraging complementary advantages involves capitalizing on the spatial cluster effect.It requires a foundation in the education chain,guided by the industrial chain,activation of the innovation chain,establishment of a talent chain,enhancement of the value chain,and the promotion of a modern vocational education structure.This structure should align with market demand and industry structure,ultimately promoting regional economic and social development.展开更多
基金supported by the project(MAD2DCM)-IMDEA Materials funded by Comunidad de Madrid and by the Recovery,Transformation and Resilience Plan and by NextGenerationEU from the European Union,and by the María de Maeztu seal of excellence from the Spanish Research Agency(CEX2018-000800-M)Mr.B.Yang wishes to express his gratitude for the support of the China Scholarship Council(202106370122).
文摘A large number of anomalous extension twins,with low or even negative twinning Schmid factors,were found to nucleate and grow in a strongly textured Mg-1Al alloy during tensile deformation along the extruded direction.The deformation mechanisms responsible for this behaviour were investigated through in-situ electron back-scattered diffraction,grain reference orientation deviation,and slip trace-modified lattice rotation.It was found that anomalous extension twins nucleated mainly at the onset of plastic deformation at or near grain boundary triple junctions.They were associated with the severe strain incompatibility between neighbour grains as a result from the differentbasal slip-induced lattice rotations.Moreover,the anomalous twins were able to grow with the applied strain due to the continuous activation ofbasal slip in different neighbour grains,which enhanced the strain incompatibility.These results reveal the complexity of the deformation mechanisms in Mg alloys at the local level when deformed along hard orientations.
基金2023 Annual Project of the China Association for Construction Education“Research on the Development Path of Private Colleges and Industry Integration in Liaoning Province Under the Strategy of Intelligent Manufacturing Strong Province”(Project number:2023239)。
文摘Against the backdrop of continuous development in the field of education,universities are encouraged to innovate their talent cultivation systems and objectives.The deep integration of industry and education has emerged as an effective strategy,aligning with the basic requirements of the new engineering education initiative and exerting a positive impact on socioeconomic development.However,an analysis of the current state of industry-education integration in universities reveals several issues that require optimization,affecting the ultimate effectiveness of integration.To optimize this phenomenon and achieve high-quality development,universities need to further explore the construction of a deep integration model of industry and education,adhering to corresponding principles to form a comprehensive system.On this basis,pathways for deep industry-education integration can be summarized.
基金V.R.F.thanks to the Aspen Technology Inc.the possibility to participate in the training course“EHM 101:Introduction to Aspen Hybrid Models for Engineering”,where,during the trial time available for AIMB he carried out the case presented in the current paper.
文摘In this work,Digital Twins based on Neural Networks for the steady state production of styrene were generated.Thus,both the Aspen Technology AI Model Builder(alternative 1)and a homemade MS Excel VBA code connected to Aspen HYSYS and Aspen Plus(alternative 2)were used with this same aim.The raw data used for generating the Digital Twins were obtained from process simulations using Aspen HYSYS and/or Aspen Plus,which were connected through a recycle-like stream via automation for solving the entire simulation flowsheet.Aspen HYSYS was used for solving the pre-heating,reaction,and stabilization sections of the process whereas Aspen Plus ensured the computing of the separation and purification columns.Both alternatives led to an excellent prediction showing the capability of creating Digital Twins from and for process simulation.
基金supported by the National Natural Science Foundation of China,No.51601154。
文摘In this work,an as-rolled AZ31 square bar with c-axis//ND(normal direction)texture was used.Side-rolling and reciprocating torsion were performed to treat the bar.Microstructure evolution and tensile-compressive properties were investigated in detail.Initial rolled AZ31 bar exhibits a large yield asymmetry along the rolling direction(RD).Reciprocating torsion can generate extension twins to introduce twin boundaries and twin-texture.The twin structure can reduce yield asymmetry.However,only limited regions in the rolled AZ31 bar can be twinned during torsion.Pre-side-rolling along the transverse direction(TD)can generate two texture components(c-axis//TD texture and c-axis//ND texture)by introducing profuse{10–12}twins.Such dual texture components help increase the regions which are favorable for twinning during torsion.Finally,combining side-rolling and reciprocating torsion generates hybrid{10–12}twins structure on the entire cross-section,resulting in a remarkably low yield asymmetry.The relevant mechanisms were discussed in detail.
基金funded by the U.S.Dept.of Energy,Office of Basic Energy Sciences Project FWP 06SCPE401support by the National Science Foundation under Grant Number 2051390。
文摘A combined experimental and computational analysis is performed to investigate the less commonly studied embryo-to-lamella transition of deformation twins in magnesium. This work aims to understand the structural variables controlling the embryo-to-lamella transition from grain boundaries. Statistical analysis of hundreds of early-stage twins in the lightly deformed microstructure reveals a prevailing wedge shape,with a much thicker base along the grain boundary(GB) where they originate and a thinner tip terminating in the crystal. The analysis also shows that the GB base is super thick and identifies a minimum GB twin thickness among all early-stage twins that is about one micron. A crystal plasticity-based full-field model is employed to calculate the driving forces to migrate the boundary of a three-dimensional GB twin embryo. The stress analysis, considering a full range of embryo shapes and neighboring grain orientations, indicate that the twin embryo is most likely going to form a wedge shape when it first propagates. The calculations predict that the thickness of the embryo at the GB needs to be significantly larger than its length into the crystal in order to propagate into the crystal. The analysis finds that the more aligned the twin embryo variant is with basal slip in the neighboring grain, the thinner the twin embryo needed for propagation.
基金supported by National Key Research and Development Program of China(2020YFB1807900).
文摘Digital twins for wide-areas(DT-WA)can model and predict the physical world with high fidelity by incorporating an artificial intelligence(AI)model.However,the AI model requires an energy-consuming updating process to keep pace with the dynamic environment,where studies are still in infancy.To reduce the updating energy,this paper proposes a distributed edge cooperation and data collection scheme.The AI model is partitioned into multiple sub-models deployed on different edge servers(ESs)co-located with access points across wide-area,to update distributively using local sensor data.To reduce the updating energy,ESs can choose to become either updating helpers or recipients of their neighboring ESs,based on sensor quantities and basic updating convergencies.Helpers would share their updated sub-model parameters with neighboring recipients,so as to reduce the latter updating workload.To minimize system energy under updating convergency and latency constraints,we further propose an algorithm to let ESs distributively optimize their cooperation identities,collect sensor data,and allocate wireless and computing resources.It comprises several constraint-release approaches,where two child optimization problems are solved,and designs a largescale multi-agent deep reinforcement learning algorithm.Simulation shows that the proposed scheme can efficiently reduce updating energy compared with the baselines.
基金supported in part by the Intergovernmental International Cooperation in Science and Technology Innovation Program under Grants 2019YFE0111600in part by National Natural Science Foundation of China under Grants 62122069,62072490,62201507,and 62071431+2 种基金in part by Science and Technology Development Fund of Macao SAR under Grants 0060/2019/A1 and 0162/2019/A3in part by FDCT-MOST Joint Project under Grant 0066/2019/AMJin part by Research Grant of University of Macao under Grant MYRG2020-00107IOTSC。
文摘In order to improve the comprehensive defense capability of data security in digital twins(DTs),an information security interaction architecture is proposed in this paper to solve the inadequacy of data protection and transmission mechanism at present.Firstly,based on the advanced encryption standard(AES)encryption,we use the keystore to expand the traditional key,and use the digital pointer to avoid the key transmission in a wireless channel.Secondly,the identity authentication technology is adopted to ensure the data integrity,and an automatic retransmission mechanism is added for the endogenous properties of the wireless channel.Finally,the software defined radio(SDR)platform composed of universal software radio peripheral(USRP)and GNU radio is used to simulate the data interaction between the physical entity and the virtual entity.The numerical results show that the DTs architecture can guarantee the encrypted data transmitted completely and decrypted accurately with high efficiency and reliability,thus providing a basis for intelligent and secure information interaction for DTs in the future.
文摘To understand the current application and development of 3D modeling in Digital Twins(DTs),abundant literatures on DTs and 3D modeling are investigated by means of literature review.The transition process from 3D modeling to DTs modeling is analyzed,as well as the current application of DTs modeling in various industries.The application of 3D DTs modeling in theelds of smartmanufacturing,smart ecology,smart transportation,and smart buildings in smart cities is analyzed in detail,and the current limitations are summarized.It is found that the 3D modeling technology in DTs has broad prospects for development and has a huge impact on all walks of life and even human lifestyles.At the same time,the development of DTs modeling relies on the development and support capabilities of mature technologies such as Big Data,Internet of Things,Cloud Computing,Articial Intelligence,and game technology.Therefore,although some results have been achieved,there are still limitations.This work aims to provide a good theoretical support for the further development of 3D DTs modeling.
文摘At present,the interpretation of regional economic development(RED)has changed from a simple evaluation of economic growth to a focus on economic growth and the optimization of economic structure,the improvement of economic relations,and the change of institutional innovation.This article uses the RED trend as the research object and constructs the RED index to conduct the theoretical analysis.Then this paper uses the attention mechanism based on digital twins and the time series network model to verify the actual data.Finally,the regional economy is predicted according to the theoretical model.The specific research work mainly includes the following aspects:1)This paper introduced the development status of research on time series networks and economic forecasting at home and abroad.2)This paper introduces the basic principles and structures of long and short-term memory(LSTM)and convolutional neural network(CNN),constructs an improved CNN-LSTM model combined with the attention mechanism,and then constructs a regional economic prediction index system.3)The best parameters of the model are selected through experiments,and the trained model is used for simulation experiment prediction.The results show that the CNN-LSTM model based on the attentionmechanism proposed in this paper has high accuracy in predicting regional economies.
基金supported by the National Natural Science Foundation of China(grant numbers 51801147,51790482,51722104,51625103,and 51621063)the National Key Re-search and Development Program of China(grant number 2017YFB0702301)the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies.
文摘{1012¯}twins were introduced into the magnesium(Mg)plate AZ31 via pre-rolling along its transverse direction.The plates,both with and without the pre-induced{1012¯}twins,were subjected to uniaxial tension along different directions.Using crystal plasticity modeling,we found that the strengthening effect of the pre-induced{1012¯}twins on the macroscopic flow stress primarily arised from the increased slip resistance caused by the boundaries,rather than the orientation hardening due to the twinning reorientation(although the latter did make its contribution in some specific loading directions).Besides,the pre-existing{1012¯}twins were found,by both experiments and simulation,to promote the activity of prismatic and pyramidal<c+a>in the parent matrix of the material.Further analysis showed that the enhanced non-basal slip activity is related to the{1012¯}twin boundaries’low micro Hall-Petch slope ratios of non-basal slips to basal slip.With the critical resolved shear stress(CRSS)obtained from crystal plasticity modeling and the orientation data from EBSD,a probability-based slip transfer model was proposed.The model predicts higher slip transfer probabilities and thus lower strain concentration tendencies at{1012¯}twin boundaries than that at grain boundaries,which agrees with the experimental observation that the strain localization was primarily associated with the latter.The present findings are helpful scientifically,in deepening our understanding of how the pre-induced{1012¯}twins affect the strength and slip activity of Mg alloys,and technologically,in guiding the design of the pre-strain protocol of Mg alloys.
文摘Despite advances in intelligent medical care,difficulties remain.Due to its complicated governance,designing,planning,improving,and managing the cardiac system remains difficult.Oversight,including intelligent monitoring,feedback systems,and management practises,is unsuccessful.Current platforms cannot deliver lifelong personal health management services.Insufficient accuracy in patient crisis warning programmes.No frequent,direct interaction between healthcare workers and patients is visible.Physical medical systems and intelligent information systems are not integrated.This study introduces the Advanced Cardiac Twin(ACT)model integrated with Artificial Neural Network(ANN)to handle real-time monitoring,decision-making,and crisis prediction.THINGSPEAK is used to create an IoT platform that accepts patient sensor data.Importing these data sets into MATLAB allows display and analysis.A myocardial ischemia research examined Health Condition Tracking’s(HCT’s)potential.In the case study,75%of the training sets(Xt),15%of the verified data,and 10%of the test data were used.Training set feature values(Xt)were given with the data.Training,Validation,and Testing accuracy rates were 99.9%,99.9%,and 99.9%,respectively.General research accuracy was 99.9%.The proposed HCT system and Artificial Neural Network(ANN)model gather historical and real-time data to manage and anticipate cardiac issues.
文摘Digital twins have emerged as a promising technology for maintenance applications,enabling organizations to simulate and monitor physical assets to improve their performance.In Operation and Maintenance(O&M),digital twin facilitates the diagnosis and prognosis of critical assets,forming the basis for smart maintenance planning and reducing downtime.However,there is a lack of standardized approaches for the qualifications of digital twins in maintenance,leading to low trustworthiness and limiting its application.This paper proposes a novel framework for the qualifications of digital twins in maintenance based on five pillars,namely fidelity,smartness,timeliness,integration,and standard compliance.We demonstrate the effectiveness of the framework through two case studies,showing how it can be implemented on digital twins for preventive maintenance and condition-based maintenance.Our proposed framework can help organizations across different industrial domains develop and implement digital twins in maintenance more effectively and efficiently,leading to significant benefits in terms of cost reduction,performance improvement,and sustainability.
基金Supported by Key R&D Program of the Ministry of Science and Technology (2019YFC0810704)Key R&D Program of Guangdong Province (2019B111102002)Shenzhen Science and Technology Program (KCXFZ202002011007040)。
文摘Backgrounds This work emphasizes the current research status of the urban Digital Twins to establish an intelligent spatiotemporal framework.A Geospatial Artificial Intelligent(GeoAI)system is developed based on the Geographic Information System and Artificial Intelligence.It integrates multi-video technology and Virtual City in urban Digital Twins.Methods Besides,an improved small object detection model is proposed:YOLOv5-Pyramid,and Siamese network video tracking models,namely MPSiam and FSSiamese,are established.Finally,an experimental platform is built to verify the georeferencing correction scheme of video images.Result The MultiplyAccumulate value of MPSiam is 0.5B,and that of ResNet50-Siam is 4.5B.Besides,the model is compressed by 4.8times.The inference speed has increased by 3.3 times,reaching 83 Frames Per Second.3%of the Average Expectation Overlap is lost.Therefore,the urban Digital Twins-oriented GeoAI framework established here has excellent performance for video georeferencing and target detection problems.
基金this paper is supposed by National Natural Science Foundation of China(12074289)Zhejiang Provincial Natural Science Foundation of China(Y23A040004)+2 种基金Teaching Reform Project of Zhejiang Province(jg20220509)Scientific Research Project of Zhejiang Graduate Education Association(2023-016)The 14th Five-year Teaching Reform Project of Zhejiang Province(jg20220522)。
文摘The concept of community is of great significance in guiding the innovation of the mechanism of industry-education integration,which can promote the integration of industry-education integration from"integration"to real"integration".We summarize the current situation of the development of industry-teaching integration mode through research,point out the"four deviations"in the development of industry-teaching integration,analyze the causes of deviations,and put forward the research strategy of"four synergistic"innovation mechanism for industry-teaching integration based on the concept of community,i.e.,synergistic development of community planning It proposes the research strategy of"four synergies"innovation mechanism based on the concept of community,namely the synergy of community planning and development,the synergy of community governance concept,the synergy of community multi-party educating mechanism,and the synergy of community fusion effect system,so as to establish collaborative ties,build a new form of cooperation concepts,safeguard the docking of talent supply and demand,and enhance the effect of integration of industry and education.
基金China Academy of Launch Vehicle Technology(Grant No.CALT-2022-03)Science and Technology on Underwater Information and Control Laboratory(Grant No.2021-JCJQ-LB-030-05).
文摘In this study, a three dimensional(3D) numerical model of six-degrees-of-freedom(6DOF) is applied to simulate the water entries of twin spheres side-by-side at different lateral distances and time intervals.The turbulence structure is described using the shear-stress transport k-ω(SST k-ω) model, and the volume of fluid(VOF) method is used to track the complex air-liquid interface. The motion of spheres during water entry is simulated using an independent overset grid. The numerical model is verified by comparing the cavity evolution results from simulations and experiments. Numerical results reveal that the time interval between the twin water entries evidently affects cavity expansion and contraction behaviors in the radial direction. However, this influence is significantly weakened by increasing the lateral distance between the two spheres. In synchronous water entries, pressure is reduced on the midline of two cavities during surface closure, which is directly related to the cavity volume. The evolution of vortexes inside the two cavities is analyzed using a velocity vector field, which is affected by the lateral distance and time interval of water entries.
基金Funded by the National Natural Science Foundation of China(Nos.51701206 and 51671187)the Shanxi Natural Science Foundation(No.2019JQ-833)+2 种基金the Anhui Natural Science Foundation(1808085QE166)the Special Scientific Research Project of Shanxi Education Committee(No.19JQ0974)the Doctoral Research Initiation Project of Yan’an University(No.YDBD2018-21)。
文摘The mechanical behavior and microstructural evolution of an Fe-30Mn-3Al-3Si twinninginduced plasticity(TWIP)steel processed using warm forging was investigated.It is found that steel processed via warm forging improves comprehensive mechanical properties compared to the TWIP steel processed via cold rolling,with a high tensile strength(R_(m))of 793 MPa,a yield strength(R_(P))of 682 MPa,an extremely large R_(P)/R_(m)ratio as high as 0.86 as well as an excellent elongation rate of 46.8%.The microstructure observation demonstrates that steel processed by warm forging consists of large and elongated grains together with fine,equiaxed grains.Complicated micro-defect configurations were also observed within the steel,including dense dislocation networks and a few coarse deformation twins.As the plastic deformation proceeds,the densities of dislocations and deformation twins significantly increase.Moreover,a great number of slip lines could be observed in the elongated grains.These findings reveal that a much more dramatic interaction between microstructural defect and dislocations glide takes place in the forging sample,wherein the fine and equiaxed grains propagated dislocations more rapidly,together with initial defect configurations,are responsible for enhanced strength properties.Meanwhile,larger,elongated grains with more prevalently activated deformation twins result in high plasticity.
基金2022-2024 Sichuan Vocational Education Talent Training and Education and Teaching Reform Research Project:Research and Practice on Comprehensive Education of Digital Media Technology Major"Posts,Courses,Competitions,and Certificates in Higher Vocational Colleges from the Perspective of Talent Chain,Innovation Chain,Education Chain,and Industrial Chain Integration"(Chuanjiaohan[2023]No.100,GZJG2022-107)2023 Sichuan Education and Scientific Research Project Key Project"Based on the Skills Master Studio's'Three-Pairs,Three-Levels,and Four-Integration'Education Path Research and Practice in Digital Media Technology Major in Higher Vocational Education"(Chuanjiaohan[2023]No.478,SCJG23A077)+2 种基金14th Five-Year Plan for Education Information Technology Research in Sichuan Province 2022 Project(DSJ2022100)2022 Chengdu Agricultural College Key Education and Teaching Reform Project(JG-202202-11)Chengdu Philosophy and Social Sciences Key Research Base:Chengdu Craftsman Culture Research Center Project(2023ZC03)。
文摘The construction of a municipal industry-education consortium is one of the important measures for the“one body,two wings,and five key points”reform of China’s modern vocational education system in the new era.It is of great significance for the integrated promotion of the three major national strategies of education,technology,and talent.Exploring the construction path of municipal industry-education consortia from the perspective of“four-chain integration”is essential for improving the quality of vocational education talents,comprehensively promoting local economic and social development,and serving the national strategy of revitalizing the country through science and education.The new generation of information technology industry-education consortium in Chengdu actively explores new paths of industry-education integration,science-education integration,and vocational-education integration.It has formed a“park+alliance”to establish a diversified collaborative construction and management mechanism,a“professional+industry”school-enterprise cooperation to promote industrial transformation and upgrading,a“teaching+research and development”to build an industry-university research innovation platform to empower high-quality development,and a“cultivation+employment”to explore a matrix style talent cultivation model,thus promoting regional governments,industries enterprises,and higher education institutions.Fully leveraging complementary advantages involves capitalizing on the spatial cluster effect.It requires a foundation in the education chain,guided by the industrial chain,activation of the innovation chain,establishment of a talent chain,enhancement of the value chain,and the promotion of a modern vocational education structure.This structure should align with market demand and industry structure,ultimately promoting regional economic and social development.