Metaverse,envisioned as the next evolution of the Internet,is expected to evolve into an innovative medium advancing information civilization.Its core characteristics,including ubiquity,seamlessness,immersion,interope...Metaverse,envisioned as the next evolution of the Internet,is expected to evolve into an innovative medium advancing information civilization.Its core characteristics,including ubiquity,seamlessness,immersion,interoperability and metaspatiotemporality,are catalyzing the development of multiple technologies and fostering a convergence between the physical and virtual worlds.Despite its potential,the critical concept of symbiosis,which involves the synchronous generation and management of virtuality from reality and serves as the cornerstone of this convergence,is often overlooked.Additionally,cumbersome service designs,stemming from the intricate interplay of various technologies and inefficient resource utilization,are impeding an ideal Metaverse ecosystem.To address these challenges,we propose a bi-model Parallel Symbiotic Metaverse(PSM)system,engineered with a Cybertwin-enabled 6G framework where Cybertwins mirror Sensing Devices(SDs)and serve a bridging role as autonomous agents.Based on this framework,the system is structured into two models.In the queue model,SDs capture environmental data that Cybertwins then coordinate and schedule.In the service model,Cybertwins manage service requests and collaborate with SDs to make responsive decisions.We incorporate two algorithms to address resource scheduling and virtual service responses,showcasing the synergistic role of Cybertwins.Moreover,our PSM system advocates for the participation of SDs from collaborators,enhancing performance while reducing operational costs for Virtual Service Operator(VSO).Finally,we comparatively analyze the efficiency and complexity of the proposed algorithms,and demonstrate the efficacy of the PSM system across multiple performance indicators.The results indicate our system can be deployed cost-effectively with Cybertwin-enabled 6G.展开更多
Few studies jointly investigate thermal and turbulent effects. In general, these subjects are treated separately. The purpose of this paper is to use the Immersed Boundary Method (IBM) coupled with the Virtual Physica...Few studies jointly investigate thermal and turbulent effects. In general, these subjects are treated separately. The purpose of this paper is to use the Immersed Boundary Method (IBM) coupled with the Virtual Physical Model (VPM) to investigate incompressible two-dimensional Newtonian flow around a heated square cylinder at constant temperature on its surface with forced convection and turbulence. The VPM model dynamically evaluates the force that the fluid exerts on the immersed surface and the thermal exchange between both in the Reynolds numbers (Re) window 40 ≤ Re ≤ 5×103 . For simulations of turbulence the Smagorinsky and Spalart-Allmaras models are used. The first model uses the Large Eddy Simulation (LES) methodology and is based on the local equilibrium hypothesis for small scales associated with the Boussinesq hypothesis, such that the energy injected into the spectrum of the turbulence balances the energy dissipated by convective effects. The second model uses the concept Unsteady Reynolds Averaged Navier-Stokes Equations (URANS), with only one transport equation for turbulent viscosity, being calibrated in pressure gradient layers. The goal of this work is to analyse the combination of the heat-transfer phenomena with the turbulence for the thermo-fluid-structure interaction in a square cylinder. For this, it was developed a C/C++ code that requires low computational costs in regards to memory and computer facilities. It is observed that, with the increase of the Reynolds number, an increase of the drag coefficient occurs, as well as reinforces the influence of the pressure distribution downstream of the cylinder, which is strongly influenced by the formation and detachment of vortices on the upper and lower sides of the square cylinder.展开更多
Museums offer a lifelong edutainment environment with flexible choices for the public and provide fruitful interdisciplinary learning resources to support competency-based education.However,the lack of proper scaffold...Museums offer a lifelong edutainment environment with flexible choices for the public and provide fruitful interdisciplinary learning resources to support competency-based education.However,the lack of proper scaffolding and supports in museums negatively affect learner learning.Further,the individual differences need to be considered to effectively support the diverse learners learning in museums.In this study,an innovative learning model to support competency education for lifelong learning in museums is proposed.A game-based learning service named CoboFun that offers various types of problem-solving activities was developed to facilitate learners’interaction with exhibits and their peers in the museum.To examine the service design of CoboFun,learners’perceptions were evaluated and the differences in their cognitive styles were examined(Field Independent(FI)and Field Dependent(FD)).The results showed that both FI and FD learners enjoyed learning with CoboFun but that flexible learning tools needed to be provided to satisfy the different needs for the learners with different cognitive styles.展开更多
Digital twin(DT)can achieve real-time information fusion and interactive feedback between virtual space and physical space.This technology involves a digital model,real-time information management,comprehensive intell...Digital twin(DT)can achieve real-time information fusion and interactive feedback between virtual space and physical space.This technology involves a digital model,real-time information management,comprehensive intelligent perception networks,etc.,and it can drive the rapid conceptual development of intelligent construction(IC)such as smart factories,smart cities,and smart medical care.Nevertheless,the actual use of DT in IC is partially pending,with numerous scientific factors still not clarified.An overall survey on pending issues and unsolved scientific factors is needed for the development of DT-driven IC.To this end,this study aims to provide a comprehensive review of the state of the art and state of the use of DT-driven IC.The use of DT in planning,design,manufacturing,operation,and maintenance management of IC is demonstrated and analyzed,following which the driving functions of DT in IC are detailed from four aspects:information perception and analysis,data mining and modeling,state assessment and prediction,intelligent optimization and decision-making.Furthermore,the future direction of research,using DT in IC,is presented with some comments and suggestions.This work will help researchers gain in-depth and systematic understanding of the use of DT,and help practitioners to better promote its implementation in IC.展开更多
Asynchronous brain-computer interfaces(aBCIs)using brain switches have demonstrated significant reliability and usability in discriminating a user's control intention and resting state.However,there is a rare rese...Asynchronous brain-computer interfaces(aBCIs)using brain switches have demonstrated significant reliability and usability in discriminating a user's control intention and resting state.However,there is a rare research demonstration of the BCI brain switch independent of visual feedback;the drawback of relying on visual channels might be disadvantageous in exploring the surrounding environment and inappropriate for some target users with severe disability.In this study,we proposed a vibrotactile-based brain switch using a virtual physical model to integrate the weak intention information to address the challenge without visual feedback.Specifically,two vibrators were worn on the left and right ankles to convey the system's swing direction to the subject,and the subject completed the periodic motor imagery task according to the vibrotactile feedback direction until the intention information was integrated enough to trigger the brain switch.A control experiment with visual feedback and vibrotactile feedback was conducted,respectively.The results showed that the triggering time for visual feedback was 54±67 s,the triggering time for vibration feedback was 53±50 s,and the false triggering rate(or false positive rate,FPR)was 1.3±1.5 and 1.1±1.4 FP/h,respectively.These results show that the proposed brain switch framework based on virtual physical systems does not need to rely on the visual pathway and can provide good reliability and triggering speed.It sheds light on developing asynchronous visual independent brain-computer interface systems.展开更多
A virtual physical system(VPS)for VIV studies of a bluff body is developed to replace the actual physical systems.It can arbitrarily and accurately control and edit the physical parameters,including mass,damping ratio...A virtual physical system(VPS)for VIV studies of a bluff body is developed to replace the actual physical systems.It can arbitrarily and accurately control and edit the physical parameters,including mass,damping ratio and spring stiffness,specifically for the mass-spring-damper system.The recursive Duhamel integral method(DIM)with unconditional stability was used for the VPS control system,addressing real-time noise filtering problem and simplifying the system as a single input and single output(SISO)one.Delay compensation and inertial force elimination methods were investigated and proposed to overcome the crucial unwanted damping effects.An experimental facility for VIV model tests by VPS was manufactured,and the bluff body model with a measurement system was specially designed to accurately sense the hydrodynamic force during VPS operation.Systematic verification experiments for parameter editing and control of an actual physical target system were conducted,showing that the VPS can reproduce the equivalent spring-damper-mass system in high fidelity with an accuracy error of less than 5%.VIV model tests for a bluff body at Reynolds numbers(Re=UD/υ,where U is the flow velocity,D represents the diameter of cylinder model,andυis the kinematic viscosity coefficient)of 5.7E4 and 2.3E5 were performed using the VPS experimental facility,presenting well-Repeated VIV responses at low Re and unexpected VIV response with a large amplitude of 2.4 D at high Re,which can cause severe fatigue damage for relevant structures.The present VPS will provide promising and powerful experimental tools for VIV studies of a bluff body to reveal the related sensitive parameter effects.展开更多
Village in Flows(流乡村 liú xiāng cūn): Village in flows refers to a new type of rural settlement that has emerged in the mobile internet era, characterized by physical dispersion and virtual clustering. While ...Village in Flows(流乡村 liú xiāng cūn): Village in flows refers to a new type of rural settlement that has emerged in the mobile internet era, characterized by physical dispersion and virtual clustering. While these villages retain their rural appearance, they have become integrated into regional or global industrial division systems. In China, prominent examples include Taobao Villages(rural communities whose economies are dominantly driven by e-commerce) and Wanghong Villages(villages that have leveraged social media and influencer marketing to become tourist destinations or promote local products).展开更多
基金partially supported by Beijing Advanced Innovation Center for Future Blockchain and Privacy Computingthe Fundamental Research Funds for the Central Universities(2024ZCJH07)。
文摘Metaverse,envisioned as the next evolution of the Internet,is expected to evolve into an innovative medium advancing information civilization.Its core characteristics,including ubiquity,seamlessness,immersion,interoperability and metaspatiotemporality,are catalyzing the development of multiple technologies and fostering a convergence between the physical and virtual worlds.Despite its potential,the critical concept of symbiosis,which involves the synchronous generation and management of virtuality from reality and serves as the cornerstone of this convergence,is often overlooked.Additionally,cumbersome service designs,stemming from the intricate interplay of various technologies and inefficient resource utilization,are impeding an ideal Metaverse ecosystem.To address these challenges,we propose a bi-model Parallel Symbiotic Metaverse(PSM)system,engineered with a Cybertwin-enabled 6G framework where Cybertwins mirror Sensing Devices(SDs)and serve a bridging role as autonomous agents.Based on this framework,the system is structured into two models.In the queue model,SDs capture environmental data that Cybertwins then coordinate and schedule.In the service model,Cybertwins manage service requests and collaborate with SDs to make responsive decisions.We incorporate two algorithms to address resource scheduling and virtual service responses,showcasing the synergistic role of Cybertwins.Moreover,our PSM system advocates for the participation of SDs from collaborators,enhancing performance while reducing operational costs for Virtual Service Operator(VSO).Finally,we comparatively analyze the efficiency and complexity of the proposed algorithms,and demonstrate the efficacy of the PSM system across multiple performance indicators.The results indicate our system can be deployed cost-effectively with Cybertwin-enabled 6G.
基金the partial support by CMUP(UID/MAT/00144/2013),which is funded by FCT(Portugal)with national(MCTES)and European structural funds(FEDER),under the partnership agreement PT2020-ext.to 2018the financial support by CAPES(Brazil)SG acknowledges the Project STRIDE-NORTE-01-0145-FEDER-000033,funded by ERDF NORTE 2020.
文摘Few studies jointly investigate thermal and turbulent effects. In general, these subjects are treated separately. The purpose of this paper is to use the Immersed Boundary Method (IBM) coupled with the Virtual Physical Model (VPM) to investigate incompressible two-dimensional Newtonian flow around a heated square cylinder at constant temperature on its surface with forced convection and turbulence. The VPM model dynamically evaluates the force that the fluid exerts on the immersed surface and the thermal exchange between both in the Reynolds numbers (Re) window 40 ≤ Re ≤ 5×103 . For simulations of turbulence the Smagorinsky and Spalart-Allmaras models are used. The first model uses the Large Eddy Simulation (LES) methodology and is based on the local equilibrium hypothesis for small scales associated with the Boussinesq hypothesis, such that the energy injected into the spectrum of the turbulence balances the energy dissipated by convective effects. The second model uses the concept Unsteady Reynolds Averaged Navier-Stokes Equations (URANS), with only one transport equation for turbulent viscosity, being calibrated in pressure gradient layers. The goal of this work is to analyse the combination of the heat-transfer phenomena with the turbulence for the thermo-fluid-structure interaction in a square cylinder. For this, it was developed a C/C++ code that requires low computational costs in regards to memory and computer facilities. It is observed that, with the increase of the Reynolds number, an increase of the drag coefficient occurs, as well as reinforces the influence of the pressure distribution downstream of the cylinder, which is strongly influenced by the formation and detachment of vortices on the upper and lower sides of the square cylinder.
文摘Museums offer a lifelong edutainment environment with flexible choices for the public and provide fruitful interdisciplinary learning resources to support competency-based education.However,the lack of proper scaffolding and supports in museums negatively affect learner learning.Further,the individual differences need to be considered to effectively support the diverse learners learning in museums.In this study,an innovative learning model to support competency education for lifelong learning in museums is proposed.A game-based learning service named CoboFun that offers various types of problem-solving activities was developed to facilitate learners’interaction with exhibits and their peers in the museum.To examine the service design of CoboFun,learners’perceptions were evaluated and the differences in their cognitive styles were examined(Field Independent(FI)and Field Dependent(FD)).The results showed that both FI and FD learners enjoyed learning with CoboFun but that flexible learning tools needed to be provided to satisfy the different needs for the learners with different cognitive styles.
基金the financial support partially provided by The Quality Engineering Project of Anhui Province(2019sjjd58,2020sxzx36)The Ministry of Education Cooperative Education Project(201901119016)+1 种基金The Chinese(Jiangsu)-Czech Bilateral Co-funding R&D Project(SBZ2018000220)the Key R&D Project of Anhui Science and Technology Department(202004b11020026).
文摘Digital twin(DT)can achieve real-time information fusion and interactive feedback between virtual space and physical space.This technology involves a digital model,real-time information management,comprehensive intelligent perception networks,etc.,and it can drive the rapid conceptual development of intelligent construction(IC)such as smart factories,smart cities,and smart medical care.Nevertheless,the actual use of DT in IC is partially pending,with numerous scientific factors still not clarified.An overall survey on pending issues and unsolved scientific factors is needed for the development of DT-driven IC.To this end,this study aims to provide a comprehensive review of the state of the art and state of the use of DT-driven IC.The use of DT in planning,design,manufacturing,operation,and maintenance management of IC is demonstrated and analyzed,following which the driving functions of DT in IC are detailed from four aspects:information perception and analysis,data mining and modeling,state assessment and prediction,intelligent optimization and decision-making.Furthermore,the future direction of research,using DT in IC,is presented with some comments and suggestions.This work will help researchers gain in-depth and systematic understanding of the use of DT,and help practitioners to better promote its implementation in IC.
基金supported by the National Natural Science Foundation of China(Grant Nos.52175023,52227808)。
文摘Asynchronous brain-computer interfaces(aBCIs)using brain switches have demonstrated significant reliability and usability in discriminating a user's control intention and resting state.However,there is a rare research demonstration of the BCI brain switch independent of visual feedback;the drawback of relying on visual channels might be disadvantageous in exploring the surrounding environment and inappropriate for some target users with severe disability.In this study,we proposed a vibrotactile-based brain switch using a virtual physical model to integrate the weak intention information to address the challenge without visual feedback.Specifically,two vibrators were worn on the left and right ankles to convey the system's swing direction to the subject,and the subject completed the periodic motor imagery task according to the vibrotactile feedback direction until the intention information was integrated enough to trigger the brain switch.A control experiment with visual feedback and vibrotactile feedback was conducted,respectively.The results showed that the triggering time for visual feedback was 54±67 s,the triggering time for vibration feedback was 53±50 s,and the false triggering rate(or false positive rate,FPR)was 1.3±1.5 and 1.1±1.4 FP/h,respectively.These results show that the proposed brain switch framework based on virtual physical systems does not need to rely on the visual pathway and can provide good reliability and triggering speed.It sheds light on developing asynchronous visual independent brain-computer interface systems.
基金support from the National Natural Science Foundation of China(No.52101323,52471291,52088102,51825903)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515240044)+2 种基金Shanghai Science and Technology Program(No.22ZR1432300)Chenguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.22CGA10)Shandong Provincial Key Laboratory of Ocean Engineering(No.kloe202302).
文摘A virtual physical system(VPS)for VIV studies of a bluff body is developed to replace the actual physical systems.It can arbitrarily and accurately control and edit the physical parameters,including mass,damping ratio and spring stiffness,specifically for the mass-spring-damper system.The recursive Duhamel integral method(DIM)with unconditional stability was used for the VPS control system,addressing real-time noise filtering problem and simplifying the system as a single input and single output(SISO)one.Delay compensation and inertial force elimination methods were investigated and proposed to overcome the crucial unwanted damping effects.An experimental facility for VIV model tests by VPS was manufactured,and the bluff body model with a measurement system was specially designed to accurately sense the hydrodynamic force during VPS operation.Systematic verification experiments for parameter editing and control of an actual physical target system were conducted,showing that the VPS can reproduce the equivalent spring-damper-mass system in high fidelity with an accuracy error of less than 5%.VIV model tests for a bluff body at Reynolds numbers(Re=UD/υ,where U is the flow velocity,D represents the diameter of cylinder model,andυis the kinematic viscosity coefficient)of 5.7E4 and 2.3E5 were performed using the VPS experimental facility,presenting well-Repeated VIV responses at low Re and unexpected VIV response with a large amplitude of 2.4 D at high Re,which can cause severe fatigue damage for relevant structures.The present VPS will provide promising and powerful experimental tools for VIV studies of a bluff body to reveal the related sensitive parameter effects.
文摘Village in Flows(流乡村 liú xiāng cūn): Village in flows refers to a new type of rural settlement that has emerged in the mobile internet era, characterized by physical dispersion and virtual clustering. While these villages retain their rural appearance, they have become integrated into regional or global industrial division systems. In China, prominent examples include Taobao Villages(rural communities whose economies are dominantly driven by e-commerce) and Wanghong Villages(villages that have leveraged social media and influencer marketing to become tourist destinations or promote local products).
