To promote the application of edge com-puting in wireless blockchain networks,this paper presents a business ecosystem,where edge comput-ing is introduced to assist blockchain users in imple-menting the mining process...To promote the application of edge com-puting in wireless blockchain networks,this paper presents a business ecosystem,where edge comput-ing is introduced to assist blockchain users in imple-menting the mining process.This paper exploits re-source trading and miner competition to enable se-cure and efficient transactions in the presented busi-ness ecosystem.The resource trading problem is for-mulated as a Stackelberg game between miner candi-dates and edge computing servers,where computing,caching,and communication resources are jointly op-timized to maximize the potential profit.Partial of-floading is introduced to further enhance the system performance when compared with the existing work.We analyze the existence and uniqueness of the Nash equilibrium and Stackelberg equilibrium.Based on the optimization result,winners are selected from the set of miner candidates by bidding and constitute the mining network.Simulation results demonstrate that the proposal is able to improve the social welfare of blockchain miners,thus stimulating more blockchain users to join the mining network.展开更多
In this paper, the dynamics of a delayed phytoplankton-zooplankton model is considered. Taking the delay due to the gestation of zooplankton as param- eter, we describe the local Hopf bifurcation by center manifold th...In this paper, the dynamics of a delayed phytoplankton-zooplankton model is considered. Taking the delay due to the gestation of zooplankton as param- eter, we describe the local Hopf bifurcation by center manifold theorem and normal form, then we discuss the global existence of periodic solution. At last, some simulations are given to support our result.展开更多
We experimentally studied con-specific interference in Ibalia leucospoides, a parasitoid of the woodwasp Sirex noctilio, on pine logs containing variable numbers of woodwasp larvae. Competiton occurred when two differ...We experimentally studied con-specific interference in Ibalia leucospoides, a parasitoid of the woodwasp Sirex noctilio, on pine logs containing variable numbers of woodwasp larvae. Competiton occurred when two different-sized female parasitoids foraged on a host patch, and consequently the small female always abandoned the patch. Regardless of host density, con-specific presence did not affect the attack rate, the number of hosts attacked, nor patch residence time by the winner, when compared to a control female that foraged alone. In contrast, con-specific presence reduced patch time and the number of hosts attacked by the loser. Finally patch time （by both） as well as number of hosts attacked （by the winner only） increased with host density per patch. Our results suggest that con-specific presence has different consequences for different-sized females during patch exploitation.展开更多
Previous investigations have shown that nifA gene is involved in nodulation and symbiotic nitrogen fixation regulation of Rhizobium. We study the role of nifA on nodulation of leguminous plants. We found that Sinorhiz...Previous investigations have shown that nifA gene is involved in nodulation and symbiotic nitrogen fixation regulation of Rhizobium. We study the role of nifA on nodulation of leguminous plants. We found that Sinorhizo-bium fredii harboring multi-copy plasmid carrying the con-stitutively expressed Klebsiella pneumoniae nifA exhibited an increase of nodulation activity and nodulation competitiveness on soybean plants. The Nod-factor secreted by the rhizobia cells containing the multi-copied nifA was assayed, and preliminary results showed that S. fredii containing the multi-copy plasmid carrying nifA produced higher strength of Nod-factor than the rhizobia containing the same plasmid carrying the vector did.展开更多
基金This work was supported by National Natural Science Foundation of China(No.62271368,No.62201421)National Natural Science Foundation of Shaanxi Province(No.2021JQ-206)+1 种基金Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110084)China Postdoctoral Science Foundation(No.2018M640960,No.2019T120879).
文摘To promote the application of edge com-puting in wireless blockchain networks,this paper presents a business ecosystem,where edge comput-ing is introduced to assist blockchain users in imple-menting the mining process.This paper exploits re-source trading and miner competition to enable se-cure and efficient transactions in the presented busi-ness ecosystem.The resource trading problem is for-mulated as a Stackelberg game between miner candi-dates and edge computing servers,where computing,caching,and communication resources are jointly op-timized to maximize the potential profit.Partial of-floading is introduced to further enhance the system performance when compared with the existing work.We analyze the existence and uniqueness of the Nash equilibrium and Stackelberg equilibrium.Based on the optimization result,winners are selected from the set of miner candidates by bidding and constitute the mining network.Simulation results demonstrate that the proposal is able to improve the social welfare of blockchain miners,thus stimulating more blockchain users to join the mining network.
基金supported by the National Natural Science Foundations of China(No.11431008)NSF of Shanghai grant(No.15ZR1423700)
文摘In this paper, the dynamics of a delayed phytoplankton-zooplankton model is considered. Taking the delay due to the gestation of zooplankton as param- eter, we describe the local Hopf bifurcation by center manifold theorem and normal form, then we discuss the global existence of periodic solution. At last, some simulations are given to support our result.
文摘We experimentally studied con-specific interference in Ibalia leucospoides, a parasitoid of the woodwasp Sirex noctilio, on pine logs containing variable numbers of woodwasp larvae. Competiton occurred when two different-sized female parasitoids foraged on a host patch, and consequently the small female always abandoned the patch. Regardless of host density, con-specific presence did not affect the attack rate, the number of hosts attacked, nor patch residence time by the winner, when compared to a control female that foraged alone. In contrast, con-specific presence reduced patch time and the number of hosts attacked by the loser. Finally patch time （by both） as well as number of hosts attacked （by the winner only） increased with host density per patch. Our results suggest that con-specific presence has different consequences for different-sized females during patch exploitation.
基金This work was supported by the State "863" High-Tech Programs and the fund of the Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences.
文摘Previous investigations have shown that nifA gene is involved in nodulation and symbiotic nitrogen fixation regulation of Rhizobium. We study the role of nifA on nodulation of leguminous plants. We found that Sinorhizo-bium fredii harboring multi-copy plasmid carrying the con-stitutively expressed Klebsiella pneumoniae nifA exhibited an increase of nodulation activity and nodulation competitiveness on soybean plants. The Nod-factor secreted by the rhizobia cells containing the multi-copied nifA was assayed, and preliminary results showed that S. fredii containing the multi-copy plasmid carrying nifA produced higher strength of Nod-factor than the rhizobia containing the same plasmid carrying the vector did.
