Blockchain is a viable solution to provide data integrity for the enormous volume of 5G IoT social data, while we need to break through the throughput bottleneck of blockchain. Sharding is a promising technology to so...Blockchain is a viable solution to provide data integrity for the enormous volume of 5G IoT social data, while we need to break through the throughput bottleneck of blockchain. Sharding is a promising technology to solve the problem of low throughput in blockchains. However, cross-shard communication hinders the effective improvement of blockchain throughput. Therefore, it is critical to reasonably allocate transactions to different shards to improve blockchain throughput. Existing research on blockchain sharding mainly focuses on shards formation, configuration, and consensus, while ignoring the negative impact of cross-shard communication on blockchain throughput. Aiming to maximize the throughput of transaction processing, we study how to allocate blockchain transactions to shards in this paper. We propose an Associated Transaction assignment algorithm based on Closest Fit (ATCF). ATCF classifies associated transactions into transaction groups which are then assigned to different shards in the non-ascending order of transaction group sizes periodically. Within each epoch, ATCF tries to select a shard that can handle all the transactions for each transaction group. If there are multiple such shards, ATCF selects the shard with the remaining processing capacity closest to the number of transactions in the transaction group. When no such shard exists, ATCF chooses the shard with the largest remaining processing capacity for the transaction group. The transaction groups that cannot be completely processed within the current epoch will be allocated in the subsequent epochs. We prove that ATCF is a 2-approximation algorithm for the associated transaction assignment problem. Simulation results show that ATCF can effectively improve the blockchain throughput and reduce the number of cross-shard transactions.展开更多
The 1997 United Nations Convention on the Law of the Non-navigational Uses of International Watercourses (UNWC) contains a negotiation framework for transboundary water rights. However, it is a subjective document ope...The 1997 United Nations Convention on the Law of the Non-navigational Uses of International Watercourses (UNWC) contains a negotiation framework for transboundary water rights. However, it is a subjective document open to a wide range of possibilities and interpretations. Water Rights Allocations (WRAs) as described by Dinar and Nigatu (2013) and Dinar and Tsur (2017) provide a limited number of quantifiable allocation possibilities based on the UNWC. It is suggested that this methodology streamlines the negotiation process and reduces the effects of hydro hegemony. These methodologies are explored and applied through a case study on the Orontes River Basin.展开更多
基金supported by Anhui Provincial Key R&D Program of China(202004a05020040),the open project of State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System in China(CEMEE2018Z0102B)the open fund of Intelligent Interconnected Systems Laboratory of Anhui Province(PA2021AKSK0114),Hefei University of Technology.
文摘Blockchain is a viable solution to provide data integrity for the enormous volume of 5G IoT social data, while we need to break through the throughput bottleneck of blockchain. Sharding is a promising technology to solve the problem of low throughput in blockchains. However, cross-shard communication hinders the effective improvement of blockchain throughput. Therefore, it is critical to reasonably allocate transactions to different shards to improve blockchain throughput. Existing research on blockchain sharding mainly focuses on shards formation, configuration, and consensus, while ignoring the negative impact of cross-shard communication on blockchain throughput. Aiming to maximize the throughput of transaction processing, we study how to allocate blockchain transactions to shards in this paper. We propose an Associated Transaction assignment algorithm based on Closest Fit (ATCF). ATCF classifies associated transactions into transaction groups which are then assigned to different shards in the non-ascending order of transaction group sizes periodically. Within each epoch, ATCF tries to select a shard that can handle all the transactions for each transaction group. If there are multiple such shards, ATCF selects the shard with the remaining processing capacity closest to the number of transactions in the transaction group. When no such shard exists, ATCF chooses the shard with the largest remaining processing capacity for the transaction group. The transaction groups that cannot be completely processed within the current epoch will be allocated in the subsequent epochs. We prove that ATCF is a 2-approximation algorithm for the associated transaction assignment problem. Simulation results show that ATCF can effectively improve the blockchain throughput and reduce the number of cross-shard transactions.
文摘The 1997 United Nations Convention on the Law of the Non-navigational Uses of International Watercourses (UNWC) contains a negotiation framework for transboundary water rights. However, it is a subjective document open to a wide range of possibilities and interpretations. Water Rights Allocations (WRAs) as described by Dinar and Nigatu (2013) and Dinar and Tsur (2017) provide a limited number of quantifiable allocation possibilities based on the UNWC. It is suggested that this methodology streamlines the negotiation process and reduces the effects of hydro hegemony. These methodologies are explored and applied through a case study on the Orontes River Basin.
