Digital Twin(DT)supports real time analysis and provides a reliable simulation platform in the Internet of Things(IoT).The creation and application of DT hinges on amounts of data,which poses pressure on the applicati...Digital Twin(DT)supports real time analysis and provides a reliable simulation platform in the Internet of Things(IoT).The creation and application of DT hinges on amounts of data,which poses pressure on the application of Artificial Intelligence(AI)for DT descriptions and intelligent decision-making.Federated Learning(FL)is a cutting-edge technology that enables geographically dispersed devices to collaboratively train a shared global model locally rather than relying on a data center to perform model training.Therefore,DT can benefit by combining with FL,successfully solving the"data island"problem in traditional AI.However,FL still faces serious challenges,such as enduring single-point failures,suffering from poison attacks,lacking effective incentive mechanisms.Before the successful deployment of DT,we should tackle the issues caused by FL.Researchers from industry and academia have recognized the potential of introducing Blockchain Technology(BT)into FL to overcome the challenges faced by FL,where BT acting as a distributed and immutable ledger,can store data in a secure,traceable,and trusted manner.However,to the best of our knowledge,a comprehensive literature review on this topic is still missing.In this paper,we review existing works about blockchain-enabled FL and visualize their prospects with DT.To this end,we first propose evaluation requirements with respect to security,faulttolerance,fairness,efficiency,cost-saving,profitability,and support for heterogeneity.Then,we classify existing literature according to the functionalities of BT in FL and analyze their advantages and disadvantages based on the proposed evaluation requirements.Finally,we discuss open problems in the existing literature and the future of DT supported by blockchain-enabled FL,based on which we further propose some directions for future research.展开更多
目的:比较传统双合垫(Twin block)矫治器与无托槽隐形矫治器矫治安氏二类下颌后缩的效果。方法:收集2020年1月至2023年7月本院93例安氏二类下颌后缩患者临床资料,按矫治器的不同分为传统TB(Twin block)组(n=48)和无托槽隐形组(n=45)。传...目的:比较传统双合垫(Twin block)矫治器与无托槽隐形矫治器矫治安氏二类下颌后缩的效果。方法:收集2020年1月至2023年7月本院93例安氏二类下颌后缩患者临床资料,按矫治器的不同分为传统TB(Twin block)组(n=48)和无托槽隐形组(n=45)。传统TB采用传统Twin block矫治器矫治,无托槽隐形组采用无托槽隐形矫治器矫治,矫治前、矫治6 m后采用数字化口腔全景X射线机测定两组蝶鞍中心、鼻根点、下牙槽座点形成的交角(Sella nasion B point angle,SNB)、蝶鞍中心、鼻根点、上牙槽座点形成的交角(Sella nasion A point angle,SNA)、上牙槽座点、鼻根点、下牙槽座点形成的交角(ANB angle,ANB)、下中切牙长轴与鼻根点-下牙槽座点连线的交角(L1-NB角)、上中切牙长轴与鼻根点和上齿槽座点连线的上交角(U1-NA角)、上中切牙切缘到鼻根点和上齿槽座点连线的垂直距离(U1-NA距)、下中切牙切缘到鼻根点-下牙槽座点连线的距离(L1-NB距)、下颌角点至下颌颏顶点的距离(Go-Gn距)水平;采用卧式口腔锥形束CT机测定上气道的总体积(V总)、最小横截面积(Smin)、最小矢状径(Lmin矢)、最小冠状径(Lmin冠)水平;同时采用中文版儿童口腔健康影响程度量表(Child perception questionnaire,CPQ11-14)评估口腔健康情况,并于矫治期间统计不良反应。结果:矫治后,两组SNB角、SNA角、ANB角、L1-NB角、U1-NA角、U1-NA距、L1-NB距、Go-Gn距均优于矫治前,组间无显著差异(P>0.05);矫治后,两组V总、Smin、Lmin矢、Lmin冠、CPQ11-14评分均高于矫治前,且传统TB组均高于无托槽隐形组(P<0.05);两组不良反应发生率比较,差异无统计学意义(P>0.05)。结论:传统Twin block与无托槽隐形矫治器矫治安氏二类下颌后缩均有良好效果,但前者改善气道效果更佳,而后者更能维持口腔健康。展开更多
As an open network architecture,Wireless Computing PowerNetworks(WCPN)pose newchallenges for achieving efficient and secure resource management in networks,because of issues such as insecure communication channels and...As an open network architecture,Wireless Computing PowerNetworks(WCPN)pose newchallenges for achieving efficient and secure resource management in networks,because of issues such as insecure communication channels and untrusted device terminals.Blockchain,as a shared,immutable distributed ledger,provides a secure resource management solution for WCPN.However,integrating blockchain into WCPN faces challenges like device heterogeneity,monitoring communication states,and dynamic network nature.Whereas Digital Twins(DT)can accurately maintain digital models of physical entities through real-time data updates and self-learning,enabling continuous optimization of WCPN,improving synchronization performance,ensuring real-time accuracy,and supporting smooth operation of WCPN services.In this paper,we propose a DT for blockchain-empowered WCPN architecture that guarantees real-time data transmission between physical entities and digital models.We adopt an enumeration-based optimal placement algorithm(EOPA)and an improved simulated annealing-based near-optimal placement algorithm(ISAPA)to achieve minimum average DT synchronization latency under the constraint of DT error.Numerical results show that the proposed solution in this paper outperforms benchmarks in terms of average synchronization latency.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 62072351in part by the Academy of Finland under Grant 308087,Grant 335262,Grant 345072,and Grant 350464+1 种基金in part by the Open Project of Zhejiang Lab under Grant 2021PD0AB01in part by the 111 Project under Grant B16037.
文摘Digital Twin(DT)supports real time analysis and provides a reliable simulation platform in the Internet of Things(IoT).The creation and application of DT hinges on amounts of data,which poses pressure on the application of Artificial Intelligence(AI)for DT descriptions and intelligent decision-making.Federated Learning(FL)is a cutting-edge technology that enables geographically dispersed devices to collaboratively train a shared global model locally rather than relying on a data center to perform model training.Therefore,DT can benefit by combining with FL,successfully solving the"data island"problem in traditional AI.However,FL still faces serious challenges,such as enduring single-point failures,suffering from poison attacks,lacking effective incentive mechanisms.Before the successful deployment of DT,we should tackle the issues caused by FL.Researchers from industry and academia have recognized the potential of introducing Blockchain Technology(BT)into FL to overcome the challenges faced by FL,where BT acting as a distributed and immutable ledger,can store data in a secure,traceable,and trusted manner.However,to the best of our knowledge,a comprehensive literature review on this topic is still missing.In this paper,we review existing works about blockchain-enabled FL and visualize their prospects with DT.To this end,we first propose evaluation requirements with respect to security,faulttolerance,fairness,efficiency,cost-saving,profitability,and support for heterogeneity.Then,we classify existing literature according to the functionalities of BT in FL and analyze their advantages and disadvantages based on the proposed evaluation requirements.Finally,we discuss open problems in the existing literature and the future of DT supported by blockchain-enabled FL,based on which we further propose some directions for future research.
文摘目的:比较传统双合垫(Twin block)矫治器与无托槽隐形矫治器矫治安氏二类下颌后缩的效果。方法:收集2020年1月至2023年7月本院93例安氏二类下颌后缩患者临床资料,按矫治器的不同分为传统TB(Twin block)组(n=48)和无托槽隐形组(n=45)。传统TB采用传统Twin block矫治器矫治,无托槽隐形组采用无托槽隐形矫治器矫治,矫治前、矫治6 m后采用数字化口腔全景X射线机测定两组蝶鞍中心、鼻根点、下牙槽座点形成的交角(Sella nasion B point angle,SNB)、蝶鞍中心、鼻根点、上牙槽座点形成的交角(Sella nasion A point angle,SNA)、上牙槽座点、鼻根点、下牙槽座点形成的交角(ANB angle,ANB)、下中切牙长轴与鼻根点-下牙槽座点连线的交角(L1-NB角)、上中切牙长轴与鼻根点和上齿槽座点连线的上交角(U1-NA角)、上中切牙切缘到鼻根点和上齿槽座点连线的垂直距离(U1-NA距)、下中切牙切缘到鼻根点-下牙槽座点连线的距离(L1-NB距)、下颌角点至下颌颏顶点的距离(Go-Gn距)水平;采用卧式口腔锥形束CT机测定上气道的总体积(V总)、最小横截面积(Smin)、最小矢状径(Lmin矢)、最小冠状径(Lmin冠)水平;同时采用中文版儿童口腔健康影响程度量表(Child perception questionnaire,CPQ11-14)评估口腔健康情况,并于矫治期间统计不良反应。结果:矫治后,两组SNB角、SNA角、ANB角、L1-NB角、U1-NA角、U1-NA距、L1-NB距、Go-Gn距均优于矫治前,组间无显著差异(P>0.05);矫治后,两组V总、Smin、Lmin矢、Lmin冠、CPQ11-14评分均高于矫治前,且传统TB组均高于无托槽隐形组(P<0.05);两组不良反应发生率比较,差异无统计学意义(P>0.05)。结论:传统Twin block与无托槽隐形矫治器矫治安氏二类下颌后缩均有良好效果,但前者改善气道效果更佳,而后者更能维持口腔健康。
基金supported by the National Natural Science Foundation of China under Grant 62272391in part by the Key Industry Innovation Chain of Shaanxi under Grant 2021ZDLGY05-08.
文摘As an open network architecture,Wireless Computing PowerNetworks(WCPN)pose newchallenges for achieving efficient and secure resource management in networks,because of issues such as insecure communication channels and untrusted device terminals.Blockchain,as a shared,immutable distributed ledger,provides a secure resource management solution for WCPN.However,integrating blockchain into WCPN faces challenges like device heterogeneity,monitoring communication states,and dynamic network nature.Whereas Digital Twins(DT)can accurately maintain digital models of physical entities through real-time data updates and self-learning,enabling continuous optimization of WCPN,improving synchronization performance,ensuring real-time accuracy,and supporting smooth operation of WCPN services.In this paper,we propose a DT for blockchain-empowered WCPN architecture that guarantees real-time data transmission between physical entities and digital models.We adopt an enumeration-based optimal placement algorithm(EOPA)and an improved simulated annealing-based near-optimal placement algorithm(ISAPA)to achieve minimum average DT synchronization latency under the constraint of DT error.Numerical results show that the proposed solution in this paper outperforms benchmarks in terms of average synchronization latency.
