Blockchain technology,with its attributes of decentralization,immutability,and traceability,has emerged as a powerful catalyst for enhancing traditional industries in terms of optimizing business processes.However,tra...Blockchain technology,with its attributes of decentralization,immutability,and traceability,has emerged as a powerful catalyst for enhancing traditional industries in terms of optimizing business processes.However,transaction performance and scalability has become the main challenges hindering the widespread adoption of blockchain.Due to its inability to meet the demands of high-frequency trading,blockchain cannot be adopted in many scenarios.To improve the transaction capacity,researchers have proposed some on-chain scaling technologies,including lightning networks,directed acyclic graph technology,state channels,and shardingmechanisms,inwhich sharding emerges as a potential scaling technology.Nevertheless,excessive cross-shard transactions and uneven shard workloads prevent the sharding mechanism from achieving the expected aim.This paper proposes a graphbased sharding scheme for public blockchain to efficiently balance the transaction distribution.Bymitigating crossshard transactions and evening-out workloads among shards,the scheme reduces transaction confirmation latency and enhances the transaction capacity of the blockchain.Therefore,the scheme can achieve a high-frequency transaction as well as a better blockchain scalability.Experiments results show that the scheme effectively reduces the cross-shard transaction ratio to a range of 35%-56%and significantly decreases the transaction confirmation latency to 6 s in a blockchain with no more than 25 shards.展开更多
Traditional Chinese Medicine(TCM)is one of the most promising programs for disease prevention and treatment.Meanwhile,the quality of TCM has garnered much attention.To ensure the quality of TCM,many works are based on...Traditional Chinese Medicine(TCM)is one of the most promising programs for disease prevention and treatment.Meanwhile,the quality of TCM has garnered much attention.To ensure the quality of TCM,many works are based on the blockchain scheme to design the traceability scheme of TCM to trace its origin.Although these schemes can ensure the integrity,sharability,credibility,and immutability of TCM more effectively,many problems are exposed with the rapid growth of TCM data in blockchains,such as expensive overhead,performance bottlenecks,and the traditional blockchain architecture is unsuitable for TCM data with dynamic growth.Motivated by the aforementioned problems,we propose a novel and lightweight TCM traceability architecture based on the blockchain using sharding(LBS-TCM).Compared to the existing blockchain-based TCM traceability system,our architecture utilizes sharding to develop a novel traceability mechanism that supports more convenient traceability operations for TCM requirements such as uploading,querying,and downloading.Specifically,our architecture consists of a leader shard blockchain layer as its main component,which employs a sharding mechanism to conveniently TCM tracing.Empirical evaluations demonstrated that our architecture showed better performance in many aspects compared to traditional blockchain architectures,such as TCM transaction processing,TCM transaction querying,TCM uploading,etc.In our architecture,tracing TCM has become a very efficient operation,which ensures the quality of TCM and provides great convenience for subsequent TCM analysis and retrospective research.展开更多
The sharding technique enables blockchain to process transactions in parallel by dividing blockchain nodes into small groups,each of which handles a subset of all transactions.One of the issues with blockchain shardin...The sharding technique enables blockchain to process transactions in parallel by dividing blockchain nodes into small groups,each of which handles a subset of all transactions.One of the issues with blockchain sharding is generating a large number of cross-shard transactions that need to be checked on the output shard as well as the destination shard.Our analysis suggests that the processing efficiency of cross-shard transactions is consistent with the barrel effect,i.e.,that efficiency is more dependent on slower processing shard.Most of the existing studies focus on how to deal with cross-shard transactions,but neglecting the fact that the relative independence between sharding results in different incentive costs between sharding.We perform a sharding analysis on 100,000 real transactions data on Ethereum,and the results show that there is a large difference in gas prices between different shards indeed.In this paper,we propose an Adaptive Weight Incentive(AWI)for Blockchain Sharding,which uses adaptive weight in place of traditional incentive,to address the problem of differing incentive costs for each shard.Take Ethereum as an example,AWI-BS computes the weight of a transaction as a function of a combination of the underlying gas price,the latency of the transaction,and the urgency of the transaction.Then the node chooses which transaction to pack based on the AWI-BS.Lastly,we also perform an in-depth analysis of AWI-BS's security and effectiveness.The evaluation indicates that AWI-BS outperforms the other alternatives in terms of transaction confirmation latency,transaction hit rate,and system throughput.展开更多
The rapid growth of the Internet of Things(IoT)has raised security concerns,including MQTT protocol-based applications that lack built-in security features and rely on resource-intensive Transport Layer Security(TLS)p...The rapid growth of the Internet of Things(IoT)has raised security concerns,including MQTT protocol-based applications that lack built-in security features and rely on resource-intensive Transport Layer Security(TLS)protocols.This paper presents an approach that utilizes blockchain technology to enhance the security of MQTT communication while maintaining efficiency.This approach involves using blockchain sharding,which enables higher scalability,improved performance,and reduced computational overhead compared to traditional blockchain approaches,making it well-suited for resource-constrained IoT environments.This approach leverages Ethereum blockchain’s smart contract mechanism to ensure trust,accountability,and user privacy.Specifically,we introduce a shard-based consensus mechanism that enables improved security while minimizing computational overhead.We also provide a user-controlled and secured algorithm using Proof-of-Access implementation to decentralize user access control to data stored in the blockchain network.The proposed approach is analyzed for usability,including metrics such as bandwidth consumption,CPU usage,memory usage,delay,access time,storage time,and jitter,which are essential for IoT application requirements.The analysis demonstrated that the approach reduces resource consumption,and the proposed system outperforms TLS and existing blockchain approaches in these metrics,regardless of the choice of the MQTT broker.Additionally,thoroughly addressing future research directions,including issues and challenges,ensures careful consideration of potential advancements in this domain.展开更多
随着企业信息化进程的不断推进和业务复杂性的提升,企业信息系统主要面临业务连续性无法保障、硬件资源利用率低、运维复杂性高等问题。本文提出了基于VMware v Sphere的基础设施即服务层企业云平台构建方案,并在某企业部署实施应用于...随着企业信息化进程的不断推进和业务复杂性的提升,企业信息系统主要面临业务连续性无法保障、硬件资源利用率低、运维复杂性高等问题。本文提出了基于VMware v Sphere的基础设施即服务层企业云平台构建方案,并在某企业部署实施应用于生产系统中,通过Sharding技术实现了数据库的扁平化。运行结果表明,私有云平台保障了业务连续性,实现了服务器、存储及网络资源的整合及动态按需分配,提升了资源利用率和运维效率,更好地满足了企业信息化发展的需求。展开更多
Recently,sharded-blockchain has attracted more and more attention.Its inherited immutabili-ty,decentralization,and promoted scalability effectively address the trust issue of the data sharing in the Internet of Things...Recently,sharded-blockchain has attracted more and more attention.Its inherited immutabili-ty,decentralization,and promoted scalability effectively address the trust issue of the data sharing in the Internet of Things(IoT).Nevertheless,the traditional random allocation between validator groups and transaction pools ignores the differences of shards,which reduces the overall system per-formance due to the unbalance between computing capacity and transaction load.To solve this prob-lem,a load balance optimization framework for sharded-blockchain enabled IoT is proposed,where the allocation between the validator groups and transaction pools is implemented reasonably by deep reinforcement learning(DRL).Specifically,based on the theoretical analysis of the intra-shard consensus and the final system consensus,the optimization of system performance is formed as a Markov decision process(MDP),and the allocation of the transaction pools,the block size,and the block interval are jointly trained in the DRL agent.The simulation results show that the proposed scheme improves the scalability of the sharded blockchain system for IoT.展开更多
In the 21st century,increasingly significant or entirely new global issues have continued to emerge and accumulate.In response to the spread of global crises such as terrorism,nuclear proliferation,the refugee crisis,...In the 21st century,increasingly significant or entirely new global issues have continued to emerge and accumulate.In response to the spread of global crises such as terrorism,nuclear proliferation,the refugee crisis,climate change,and the spread of disease,the existing global governance system“has lost the momentum for progress.”*1 Its effectiveness under the leadership of certain Western countries has begun to be questioned by many parties and has fallen into a dilemma marked by stagnation.The reform of the global governance system has become an inevitable requirement for international relations.With today?s unprecedented changes,not only are global financial,developmental,and ecological issues constantly erupting,but the sudden emergence of the new COVID-19 virus poses a serious threat to human health and safety.In this context,the world is obviously facing instability and uncertainty,and the reform o f the global governance system is at a historical turning point.The existing global governance mechanisms have been unable to adapt to the new complex and diverse situation,and the old global order is further disintegrating.China is actively promoting for the reform of the global governance system to build a community with a shared future for mankind that will lead the world into a new global governance structure.It is also an important practice of China's major-country diplomacy with Chinese characteristics in the new era.展开更多
With the rapid advancement of the Internet of Things(IoT),the typical application of wireless body area networks(WBANs)based smart healthcare has drawn wide attention from all sectors of society.To alleviate the press...With the rapid advancement of the Internet of Things(IoT),the typical application of wireless body area networks(WBANs)based smart healthcare has drawn wide attention from all sectors of society.To alleviate the pressing challenges,such as resource limitations,low-latency service provision,mass data processing,rigid security demands,and the lack of a central entity,the advanced solutions of fog computing,software-defined networking(SDN)and blockchain are leveraged in this work.On the basis of these solutions,a task offloading strategy with a centralized low-latency,secure and reliable decision-making algorithm having powerful emergency handling capacity(LSRDM-EH)is designed to facilitate the resource-constrained edge devices for task offloading.Additionally,to well ensure the security of the entire network,a comprehensive blockchain-based two-layer and multidimensional security strategy is proposed.Furthermore,to tackle the inherent time-inefficiency problem of blockchain,we propose a blockchain sharding scheme to reduce system time latency.Extensive simulation has been conducted to validate the performance of the proposed measures,and numerical results verify the superiority of our methods with lower time-latency,higher reliability and security.展开更多
Blockchain technology is used in edge computing(EC) systems to solve the security problems caused by single point of failure(SPOF) due to data loss, task execution failure, or control by malicious nodes. However, the ...Blockchain technology is used in edge computing(EC) systems to solve the security problems caused by single point of failure(SPOF) due to data loss, task execution failure, or control by malicious nodes. However, the disadvantage of blockchain is high latency, which contradicts the strict latency requirements of EC services. The existing single-level sharded blockchain system(SLSBS) cannot provide different quality of service for different tasks. To solve these problems, a multi-level sharded blockchain system(MLSBS) based on genetic algorithm(GA) is proposed. The shards are classified according to the delay of the service, and the parameters such as the shard size of different shards are different. Using the GA, the MLSBS obtains the optimal resource allocation strategy that achieves maximum security. Simulation results show that the proposed scheme outperforms SLSBS.展开更多
A volcanic ash layer was observed in the 3 ice cores on the Nelson Ice Cap,Antarctica.Acomparison of major elemental composition of glass shards from the 3 tephra layers with average whole-rockcompositions of 1967-197...A volcanic ash layer was observed in the 3 ice cores on the Nelson Ice Cap,Antarctica.Acomparison of major elemental composition of glass shards from the 3 tephra layers with average whole-rockcompositions of 1967-1970 eruptions on the Deception Island and of glass shards from other suspected De-ception Island eruptions collected from Antarctic ice and firn indicate that the most reasonable source for thetephra in the Nelson Ice Cap cores is the 1970 eruption on the Deception Island.From the depth of the vol-canic ash layer and measured density profile of the cores,the net accumulation rate at the summit,CoreGW,is 1200 g·cm<sup>-2</sup>·a<sup>-1</sup> during the past 20 years,and the net accumulation rates are 700 g·cm<sup>-2</sup>·a<sup>-1</sup>and 6 g·cm<sup>-2</sup>·a<sup>-1</sup> at sites N30 and N50,respectively.In the eastern part of the Nelson Ice Cap,the accu-mulation rate may be higher than that in the northern part,because no volcanic ash in ice cores was observedat similar depths collected from this region.展开更多
基金supported by Shandong Provincial Key Research and Development Program of China(2021CXGC010107,2020CXGC010107)the Shandong Provincial Natural Science Foundation of China(ZR2020KF035)the New 20 Project of Higher Education of Jinan,China(202228017).
文摘Blockchain technology,with its attributes of decentralization,immutability,and traceability,has emerged as a powerful catalyst for enhancing traditional industries in terms of optimizing business processes.However,transaction performance and scalability has become the main challenges hindering the widespread adoption of blockchain.Due to its inability to meet the demands of high-frequency trading,blockchain cannot be adopted in many scenarios.To improve the transaction capacity,researchers have proposed some on-chain scaling technologies,including lightning networks,directed acyclic graph technology,state channels,and shardingmechanisms,inwhich sharding emerges as a potential scaling technology.Nevertheless,excessive cross-shard transactions and uneven shard workloads prevent the sharding mechanism from achieving the expected aim.This paper proposes a graphbased sharding scheme for public blockchain to efficiently balance the transaction distribution.Bymitigating crossshard transactions and evening-out workloads among shards,the scheme reduces transaction confirmation latency and enhances the transaction capacity of the blockchain.Therefore,the scheme can achieve a high-frequency transaction as well as a better blockchain scalability.Experiments results show that the scheme effectively reduces the cross-shard transaction ratio to a range of 35%-56%and significantly decreases the transaction confirmation latency to 6 s in a blockchain with no more than 25 shards.
基金supported by the research and innovation program for graduate students of the Guangzhou University of Traditional Chinese MedicineThis work is also partially supported by the National Key Research and Development Program of China(2019YFC1710402)the research on tracing TCM Electronic Medical Records Based on the Lightweight Blockchain of Guangdong Provincial Bureau of Traditional Chinese Medicine(20222045).
文摘Traditional Chinese Medicine(TCM)is one of the most promising programs for disease prevention and treatment.Meanwhile,the quality of TCM has garnered much attention.To ensure the quality of TCM,many works are based on the blockchain scheme to design the traceability scheme of TCM to trace its origin.Although these schemes can ensure the integrity,sharability,credibility,and immutability of TCM more effectively,many problems are exposed with the rapid growth of TCM data in blockchains,such as expensive overhead,performance bottlenecks,and the traditional blockchain architecture is unsuitable for TCM data with dynamic growth.Motivated by the aforementioned problems,we propose a novel and lightweight TCM traceability architecture based on the blockchain using sharding(LBS-TCM).Compared to the existing blockchain-based TCM traceability system,our architecture utilizes sharding to develop a novel traceability mechanism that supports more convenient traceability operations for TCM requirements such as uploading,querying,and downloading.Specifically,our architecture consists of a leader shard blockchain layer as its main component,which employs a sharding mechanism to conveniently TCM tracing.Empirical evaluations demonstrated that our architecture showed better performance in many aspects compared to traditional blockchain architectures,such as TCM transaction processing,TCM transaction querying,TCM uploading,etc.In our architecture,tracing TCM has become a very efficient operation,which ensures the quality of TCM and provides great convenience for subsequent TCM analysis and retrospective research.
基金supported by FDCT under its General R&D Subsidy Program Fund(0038/2022/A)。
文摘The sharding technique enables blockchain to process transactions in parallel by dividing blockchain nodes into small groups,each of which handles a subset of all transactions.One of the issues with blockchain sharding is generating a large number of cross-shard transactions that need to be checked on the output shard as well as the destination shard.Our analysis suggests that the processing efficiency of cross-shard transactions is consistent with the barrel effect,i.e.,that efficiency is more dependent on slower processing shard.Most of the existing studies focus on how to deal with cross-shard transactions,but neglecting the fact that the relative independence between sharding results in different incentive costs between sharding.We perform a sharding analysis on 100,000 real transactions data on Ethereum,and the results show that there is a large difference in gas prices between different shards indeed.In this paper,we propose an Adaptive Weight Incentive(AWI)for Blockchain Sharding,which uses adaptive weight in place of traditional incentive,to address the problem of differing incentive costs for each shard.Take Ethereum as an example,AWI-BS computes the weight of a transaction as a function of a combination of the underlying gas price,the latency of the transaction,and the urgency of the transaction.Then the node chooses which transaction to pack based on the AWI-BS.Lastly,we also perform an in-depth analysis of AWI-BS's security and effectiveness.The evaluation indicates that AWI-BS outperforms the other alternatives in terms of transaction confirmation latency,transaction hit rate,and system throughput.
文摘The rapid growth of the Internet of Things(IoT)has raised security concerns,including MQTT protocol-based applications that lack built-in security features and rely on resource-intensive Transport Layer Security(TLS)protocols.This paper presents an approach that utilizes blockchain technology to enhance the security of MQTT communication while maintaining efficiency.This approach involves using blockchain sharding,which enables higher scalability,improved performance,and reduced computational overhead compared to traditional blockchain approaches,making it well-suited for resource-constrained IoT environments.This approach leverages Ethereum blockchain’s smart contract mechanism to ensure trust,accountability,and user privacy.Specifically,we introduce a shard-based consensus mechanism that enables improved security while minimizing computational overhead.We also provide a user-controlled and secured algorithm using Proof-of-Access implementation to decentralize user access control to data stored in the blockchain network.The proposed approach is analyzed for usability,including metrics such as bandwidth consumption,CPU usage,memory usage,delay,access time,storage time,and jitter,which are essential for IoT application requirements.The analysis demonstrated that the approach reduces resource consumption,and the proposed system outperforms TLS and existing blockchain approaches in these metrics,regardless of the choice of the MQTT broker.Additionally,thoroughly addressing future research directions,including issues and challenges,ensures careful consideration of potential advancements in this domain.
文摘随着企业信息化进程的不断推进和业务复杂性的提升,企业信息系统主要面临业务连续性无法保障、硬件资源利用率低、运维复杂性高等问题。本文提出了基于VMware v Sphere的基础设施即服务层企业云平台构建方案,并在某企业部署实施应用于生产系统中,通过Sharding技术实现了数据库的扁平化。运行结果表明,私有云平台保障了业务连续性,实现了服务器、存储及网络资源的整合及动态按需分配,提升了资源利用率和运维效率,更好地满足了企业信息化发展的需求。
基金Supported by the National Natural Science Foundation of China(No.61901011)the Foundation of Beijing Municipal Commission of Edu-cation(No.KM202010005017,KM202110005021).
文摘Recently,sharded-blockchain has attracted more and more attention.Its inherited immutabili-ty,decentralization,and promoted scalability effectively address the trust issue of the data sharing in the Internet of Things(IoT).Nevertheless,the traditional random allocation between validator groups and transaction pools ignores the differences of shards,which reduces the overall system per-formance due to the unbalance between computing capacity and transaction load.To solve this prob-lem,a load balance optimization framework for sharded-blockchain enabled IoT is proposed,where the allocation between the validator groups and transaction pools is implemented reasonably by deep reinforcement learning(DRL).Specifically,based on the theoretical analysis of the intra-shard consensus and the final system consensus,the optimization of system performance is formed as a Markov decision process(MDP),and the allocation of the transaction pools,the block size,and the block interval are jointly trained in the DRL agent.The simulation results show that the proposed scheme improves the scalability of the sharded blockchain system for IoT.
文摘In the 21st century,increasingly significant or entirely new global issues have continued to emerge and accumulate.In response to the spread of global crises such as terrorism,nuclear proliferation,the refugee crisis,climate change,and the spread of disease,the existing global governance system“has lost the momentum for progress.”*1 Its effectiveness under the leadership of certain Western countries has begun to be questioned by many parties and has fallen into a dilemma marked by stagnation.The reform of the global governance system has become an inevitable requirement for international relations.With today?s unprecedented changes,not only are global financial,developmental,and ecological issues constantly erupting,but the sudden emergence of the new COVID-19 virus poses a serious threat to human health and safety.In this context,the world is obviously facing instability and uncertainty,and the reform o f the global governance system is at a historical turning point.The existing global governance mechanisms have been unable to adapt to the new complex and diverse situation,and the old global order is further disintegrating.China is actively promoting for the reform of the global governance system to build a community with a shared future for mankind that will lead the world into a new global governance structure.It is also an important practice of China's major-country diplomacy with Chinese characteristics in the new era.
基金supported by the National Natural Science Foundation of China(No.61761007)the Scientific Research Project of Guangxi University Xingjian College of Science and Liberal Arts(No.Y2021ZK03)。
文摘With the rapid advancement of the Internet of Things(IoT),the typical application of wireless body area networks(WBANs)based smart healthcare has drawn wide attention from all sectors of society.To alleviate the pressing challenges,such as resource limitations,low-latency service provision,mass data processing,rigid security demands,and the lack of a central entity,the advanced solutions of fog computing,software-defined networking(SDN)and blockchain are leveraged in this work.On the basis of these solutions,a task offloading strategy with a centralized low-latency,secure and reliable decision-making algorithm having powerful emergency handling capacity(LSRDM-EH)is designed to facilitate the resource-constrained edge devices for task offloading.Additionally,to well ensure the security of the entire network,a comprehensive blockchain-based two-layer and multidimensional security strategy is proposed.Furthermore,to tackle the inherent time-inefficiency problem of blockchain,we propose a blockchain sharding scheme to reduce system time latency.Extensive simulation has been conducted to validate the performance of the proposed measures,and numerical results verify the superiority of our methods with lower time-latency,higher reliability and security.
文摘Blockchain technology is used in edge computing(EC) systems to solve the security problems caused by single point of failure(SPOF) due to data loss, task execution failure, or control by malicious nodes. However, the disadvantage of blockchain is high latency, which contradicts the strict latency requirements of EC services. The existing single-level sharded blockchain system(SLSBS) cannot provide different quality of service for different tasks. To solve these problems, a multi-level sharded blockchain system(MLSBS) based on genetic algorithm(GA) is proposed. The shards are classified according to the delay of the service, and the parameters such as the shard size of different shards are different. Using the GA, the MLSBS obtains the optimal resource allocation strategy that achieves maximum security. Simulation results show that the proposed scheme outperforms SLSBS.
基金the National Natural Science Foundation of China the State Committee for Antarctic Research of China
文摘A volcanic ash layer was observed in the 3 ice cores on the Nelson Ice Cap,Antarctica.Acomparison of major elemental composition of glass shards from the 3 tephra layers with average whole-rockcompositions of 1967-1970 eruptions on the Deception Island and of glass shards from other suspected De-ception Island eruptions collected from Antarctic ice and firn indicate that the most reasonable source for thetephra in the Nelson Ice Cap cores is the 1970 eruption on the Deception Island.From the depth of the vol-canic ash layer and measured density profile of the cores,the net accumulation rate at the summit,CoreGW,is 1200 g·cm<sup>-2</sup>·a<sup>-1</sup> during the past 20 years,and the net accumulation rates are 700 g·cm<sup>-2</sup>·a<sup>-1</sup>and 6 g·cm<sup>-2</sup>·a<sup>-1</sup> at sites N30 and N50,respectively.In the eastern part of the Nelson Ice Cap,the accu-mulation rate may be higher than that in the northern part,because no volcanic ash in ice cores was observedat similar depths collected from this region.
