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
The diversity of Linux versions brings challenges to Linux memory analysis,which is an established technique in security and forensic investigations.During memory forensics,kernel data structures are essential informa...The diversity of Linux versions brings challenges to Linux memory analysis,which is an established technique in security and forensic investigations.During memory forensics,kernel data structures are essential information.Existing solutions obtain this information by analyzing debugging information or by decompiling kernel functions to handle a certain range of versions.In this paper,by collecting and analyzing a number of Linux versions,we characterize the properties of different Linux kernel versions and how struct offsets change between versions.Furthermore,the Linux kernel provides over 10,000 configurable features,which leads to different kernel structure layouts for the same kernel version.To deal with this problem,we propose a method of identifying kernel struct layout based on brute-force matching.By examining the relationships between kernel structures,common features are extracted and exploited for brute-force matching.The experimental results show that the proposed technology can deduce structure member offsets accurately and efficiently.展开更多
In this paper, we investigate heterogeneous multiscale method （HMM） for the optimal control problem with distributed control constraints governed by elliptic equations with highly oscillatory coefficients. The state...In this paper, we investigate heterogeneous multiscale method （HMM） for the optimal control problem with distributed control constraints governed by elliptic equations with highly oscillatory coefficients. The state variable and co-state variable are approximated by the multiscale discretization scheme that relies on coupled macro and micro finite elements, whereas the control variable is discretized by the piecewise constant. By applying the well- known Lions＇ Lemma to the discretized optimal control problem, we obtain the necessary and sufficient optimality conditions. A priori error estimates in both L^2 and H^1 norms are derived for the state, co-state and the control variable with uniform bound constants. Finally, numerical examples are presented to illustrate our theoretical results.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.
文摘The diversity of Linux versions brings challenges to Linux memory analysis,which is an established technique in security and forensic investigations.During memory forensics,kernel data structures are essential information.Existing solutions obtain this information by analyzing debugging information or by decompiling kernel functions to handle a certain range of versions.In this paper,by collecting and analyzing a number of Linux versions,we characterize the properties of different Linux kernel versions and how struct offsets change between versions.Furthermore,the Linux kernel provides over 10,000 configurable features,which leads to different kernel structure layouts for the same kernel version.To deal with this problem,we propose a method of identifying kernel struct layout based on brute-force matching.By examining the relationships between kernel structures,common features are extracted and exploited for brute-force matching.The experimental results show that the proposed technology can deduce structure member offsets accurately and efficiently.
基金The work was supported by the Shandong Province Outstanding Y- oung Scientists Research Award Fund Project （Grant No. BS2013DX010）, by the Natural Science Foundation of Shandong Province, China （Grant No. ZR2011FQ030, ZR2013FQ001, ZR2013FM025）, by Natural Science Foundation of China （Grant No. 11501326 and 11571356）, and by the Shandong Academy of Sciences Youth Fund Project （Grant No. 2013QN007）.
文摘In this paper, we investigate heterogeneous multiscale method （HMM） for the optimal control problem with distributed control constraints governed by elliptic equations with highly oscillatory coefficients. The state variable and co-state variable are approximated by the multiscale discretization scheme that relies on coupled macro and micro finite elements, whereas the control variable is discretized by the piecewise constant. By applying the well- known Lions＇ Lemma to the discretized optimal control problem, we obtain the necessary and sufficient optimality conditions. A priori error estimates in both L^2 and H^1 norms are derived for the state, co-state and the control variable with uniform bound constants. Finally, numerical examples are presented to illustrate our theoretical results.
