For TDMA MAC protocols in wireless sensor networks (WSNs), redundancy and retransmission are two important methods to provide high end-to-end transmission reliability. Since reliable transmissions will lead to more en...For TDMA MAC protocols in wireless sensor networks (WSNs), redundancy and retransmission are two important methods to provide high end-to-end transmission reliability. Since reliable transmissions will lead to more energy consumption, there exists an intrinsic tradeoff between transmission reliability and energy efficiency. For each link, we name the number of its reserved time slots in each MAC superframe as a replicator factor. In the following paper, we propose a reliability-lifetime tradeoff framework (RLTF) for WSNs to study replicator factor control problem. First, for the redundancy TDMA MAC, we formulate replicator factor control problem as convex programming. By the gradient projection method, we develop a fully distributed algorithm to solve the convex programming. Second, for the retransmission TDMA MAC, we set the retransmission upper bound for each link according to the optimal replicator factors under the redundancy MAC and compute the total communication overhead for the retransmission MAC. Finally, we compare the communication overhead of these two MAC protocols under different channel conditions.展开更多
The phytohormone abscisic acid （ABA） regulates many aspects of division. Previous study indicates that ABA treatment increases DNA plant growth, including seed germination, root growth and cell damage and somatic ho...The phytohormone abscisic acid （ABA） regulates many aspects of division. Previous study indicates that ABA treatment increases DNA plant growth, including seed germination, root growth and cell damage and somatic homologous recombination （HR） in Arabi- dopsis abo4/pol ε （aba overly-sensitive 4/DNA polymerase ε） mutants. DNA replication factor C （RFC） complex is required for loading PCNA （Proliferating Cell Nuclear Antigen） during DNA replication. The defect in RFC1, the largest subunit of RFC, causes the high HR and DNA damage sensitivity in Arabidopsis. Here we found that like pol e/abo4, rfcl is sensitive to ABA in both ABA-inhibiting seed germination and root growth. However, ABA treatment greatly reduces HR and also reduces the expression of the DNA-damaged marker genes in ,rfcl. These results suggest that RFCI plays critical roles in ABA-mediated HR in Arabidopsis.展开更多
基金supported by the National Science Foundation of China (No. 60704046, 60725312, 60804067)the National Science Foundation of Liaoning Province (No. 20092083)the National 863 high technology research and development Plan (No. 2007AA04Z173, 2007AA041201)
文摘For TDMA MAC protocols in wireless sensor networks (WSNs), redundancy and retransmission are two important methods to provide high end-to-end transmission reliability. Since reliable transmissions will lead to more energy consumption, there exists an intrinsic tradeoff between transmission reliability and energy efficiency. For each link, we name the number of its reserved time slots in each MAC superframe as a replicator factor. In the following paper, we propose a reliability-lifetime tradeoff framework (RLTF) for WSNs to study replicator factor control problem. First, for the redundancy TDMA MAC, we formulate replicator factor control problem as convex programming. By the gradient projection method, we develop a fully distributed algorithm to solve the convex programming. Second, for the retransmission TDMA MAC, we set the retransmission upper bound for each link according to the optimal replicator factors under the redundancy MAC and compute the total communication overhead for the retransmission MAC. Finally, we compare the communication overhead of these two MAC protocols under different channel conditions.
文摘The phytohormone abscisic acid （ABA） regulates many aspects of division. Previous study indicates that ABA treatment increases DNA plant growth, including seed germination, root growth and cell damage and somatic homologous recombination （HR） in Arabi- dopsis abo4/pol ε （aba overly-sensitive 4/DNA polymerase ε） mutants. DNA replication factor C （RFC） complex is required for loading PCNA （Proliferating Cell Nuclear Antigen） during DNA replication. The defect in RFC1, the largest subunit of RFC, causes the high HR and DNA damage sensitivity in Arabidopsis. Here we found that like pol e/abo4, rfcl is sensitive to ABA in both ABA-inhibiting seed germination and root growth. However, ABA treatment greatly reduces HR and also reduces the expression of the DNA-damaged marker genes in ,rfcl. These results suggest that RFCI plays critical roles in ABA-mediated HR in Arabidopsis.
