Programs take on changing behavior at nmtime in a simultaneous multithreading （SMT） environment. How reasonably common resources are distributed among the threads significantly determines the throughput and fairness...Programs take on changing behavior at nmtime in a simultaneous multithreading （SMT） environment. How reasonably common resources are distributed among the threads significantly determines the throughput and fairness performance in SMT processors. Existing resource distribution methods either mainly rely on the front-end fetch policy, or make distribution decisions according to the limited information from the pipeline. It is difficult for them to efficiently catch the various resource requirements of the threads. This work presents a spatially triggered dissipative resource distribution （SDRD） policy for SMT processors, its two parts, the self-organization mechanism that is driven by the real-time instructions per cycle （IPC） performance and the introduction of chaos that tries to control the diversity Of trial resource distributions, work together to supply sustaining resource distribution optimization for changing program behavior. Simulation results show that SDRD with fine-grained diversity controlling is more effective than that with a coarse-grained one. And SDRD benefits much from its two well-coordinated parts, providing potential fairness gains as well as good throughput gains. Meanings and settings of important SDRD parameters are also discussed.展开更多
This study proposes a recoverable stress testing algorithm （RSTA） for such special devices as compression/decompression card and encryption/deeryption card. It uses a chaos function to generate a random sequence, an...This study proposes a recoverable stress testing algorithm （RSTA） for such special devices as compression/decompression card and encryption/deeryption card. It uses a chaos function to generate a random sequence, and then, according to the random sequence, generates an effective command sequence. The dispatch of command obeys a special schedule strategy we designed for such devices, i.e., the commands are sent according to the command sequence, and the complete commands are put in a buffer for further result check. RSTA is used to test the HIFN compression acceleration card SAICHI-1000. Test results show that RSTA can make the card work continuously and adequately.展开更多
Wireless sensor networks(WSNs)are vulnerable to security attacks due to their deployment and resource constraints.Considering that most large-scale WSNs follow a two-tiered architecture,we propose an efficient and den...Wireless sensor networks(WSNs)are vulnerable to security attacks due to their deployment and resource constraints.Considering that most large-scale WSNs follow a two-tiered architecture,we propose an efficient and denial-of-service(DoS)-resistant user authentication scheme for two-tiered WSNs.The proposed approach reduces the computational load,since it performs only simple operations,such as exclusive-OR and a one-way hash function.This feature is more suitable for the resource-limited sensor nodes and mobile devices.And it is unnecessary for master nodes to forward login request messages to the base station,or maintain a long user list.In addition,pseudonym identity is introduced to preserve user anonymity.Through clever design,our proposed scheme can prevent smart card breaches.Finally,security and performance analysis demonstrates the effectiveness and robustness of the proposed scheme.展开更多
This paper presents a robust lossless data hiding scheme. The original cover image can be recovered without any distortion after data extraction if the stego-image remains intact, and conversely, the hidden data can s...This paper presents a robust lossless data hiding scheme. The original cover image can be recovered without any distortion after data extraction if the stego-image remains intact, and conversely, the hidden data can still be extracted correctly if the stego-image goes through JPEG compression to some extent. A cover image is divided into a number of non-overlapping blocks, and the arithmetic difference of each block is calculated. By shifting the arithmetic difference value, we can embed bits into the blocks. The shift quantity and shifting rule are fixed for all blocks, and reversibility is achieved. Furthermore, because the bit-0- and bit-1-zones are separated and the particularity of the arithmetic differences, minor changes applied to the stego-image generated by non-malicious attacks such as JPEG compression will not cause the bit-0- and bit-l-zones to overlap, and robustness is achieved. The new embedding mechanism can enhance embedding capacity and the addition of a threshold can make the al- gorithm more robust. Experimental results showed that, compared with previous schemes, the performance of the proposed scheme is significantly improved.展开更多
基金the Hi-Tech Research and Development Pro-gram (863) of China (No. 2006AA01Z431) the Key Science andTechnology Program of Zhejiang Province (Nos. 2007C11068 and2007C11088), China
文摘Programs take on changing behavior at nmtime in a simultaneous multithreading （SMT） environment. How reasonably common resources are distributed among the threads significantly determines the throughput and fairness performance in SMT processors. Existing resource distribution methods either mainly rely on the front-end fetch policy, or make distribution decisions according to the limited information from the pipeline. It is difficult for them to efficiently catch the various resource requirements of the threads. This work presents a spatially triggered dissipative resource distribution （SDRD） policy for SMT processors, its two parts, the self-organization mechanism that is driven by the real-time instructions per cycle （IPC） performance and the introduction of chaos that tries to control the diversity Of trial resource distributions, work together to supply sustaining resource distribution optimization for changing program behavior. Simulation results show that SDRD with fine-grained diversity controlling is more effective than that with a coarse-grained one. And SDRD benefits much from its two well-coordinated parts, providing potential fairness gains as well as good throughput gains. Meanings and settings of important SDRD parameters are also discussed.
基金the Hi-Tech Research and Development Pro-gram (863) of China (No. 2006AA01Z431)the Giant Project of Zhejiang Province, China (No. 2006C11105)
文摘This study proposes a recoverable stress testing algorithm （RSTA） for such special devices as compression/decompression card and encryption/deeryption card. It uses a chaos function to generate a random sequence, and then, according to the random sequence, generates an effective command sequence. The dispatch of command obeys a special schedule strategy we designed for such devices, i.e., the commands are sent according to the command sequence, and the complete commands are put in a buffer for further result check. RSTA is used to test the HIFN compression acceleration card SAICHI-1000. Test results show that RSTA can make the card work continuously and adequately.
文摘Wireless sensor networks(WSNs)are vulnerable to security attacks due to their deployment and resource constraints.Considering that most large-scale WSNs follow a two-tiered architecture,we propose an efficient and denial-of-service(DoS)-resistant user authentication scheme for two-tiered WSNs.The proposed approach reduces the computational load,since it performs only simple operations,such as exclusive-OR and a one-way hash function.This feature is more suitable for the resource-limited sensor nodes and mobile devices.And it is unnecessary for master nodes to forward login request messages to the base station,or maintain a long user list.In addition,pseudonym identity is introduced to preserve user anonymity.Through clever design,our proposed scheme can prevent smart card breaches.Finally,security and performance analysis demonstrates the effectiveness and robustness of the proposed scheme.
基金supported in part by the Major Science and Technology Special Project of Zhejiang Province, China (No. 2007C11088)the Science and Technology Project of Zhejiang Province, China (No. 2008C21077)
文摘This paper presents a robust lossless data hiding scheme. The original cover image can be recovered without any distortion after data extraction if the stego-image remains intact, and conversely, the hidden data can still be extracted correctly if the stego-image goes through JPEG compression to some extent. A cover image is divided into a number of non-overlapping blocks, and the arithmetic difference of each block is calculated. By shifting the arithmetic difference value, we can embed bits into the blocks. The shift quantity and shifting rule are fixed for all blocks, and reversibility is achieved. Furthermore, because the bit-0- and bit-1-zones are separated and the particularity of the arithmetic differences, minor changes applied to the stego-image generated by non-malicious attacks such as JPEG compression will not cause the bit-0- and bit-l-zones to overlap, and robustness is achieved. The new embedding mechanism can enhance embedding capacity and the addition of a threshold can make the al- gorithm more robust. Experimental results showed that, compared with previous schemes, the performance of the proposed scheme is significantly improved.
