Moving target defense （MT_D） is a novel way to alter the asymmetric situation of attacks and defenses, and a lot of MTD studies have been carried out recently. However, relevant analysis for the defense mechanism of...Moving target defense （MT_D） is a novel way to alter the asymmetric situation of attacks and defenses, and a lot of MTD studies have been carried out recently. However, relevant analysis for the defense mechanism of the MTD technology is still absent. In this paper, we analyze the defense mechanism of MTD technology in two dimensions. First, we present a new defense model named MP2R to describe the proactivity and effect of MTD technology intuitively. Second, we use the incomplete information dynamic game theory to verify the proactivity and effect of MTD technology. Specifically, we model the interaction between a defender who equips a server with different types of MTD techniques and a visitor who can be a user or an attacker, and analyze the equilibria and their conditions for these models. Then, we take an existing incomplete information dynamic game model for traditional defense and its equilibrium result as baseline for comparison, to validate the proactivity and effect of MTD technology. We also identify the factors that will influence the proactivity and effectiveness of the MTD approaches. This work gives theoretical support for understanding the defense process and defense mechanism of MTD technology and provides suggestions to improve the effectiveness of MTD approaches.展开更多
Aims Climate warming and increasing nitrogen(N)deposition have influenced plant nutrient status and thus plant carbon(C)fixation and vegetation composition in boreal peatlands.Phenols,which are secondary metabolites i...Aims Climate warming and increasing nitrogen(N)deposition have influenced plant nutrient status and thus plant carbon(C)fixation and vegetation composition in boreal peatlands.Phenols,which are secondary metabolites in plants for defense and adaptation,also play important roles in regulating peatland C dynamics due to their anti-decomposition properties.However,how the phenolic levels of different functional types of plants vary depending on nutrient availability remain unclear in boreal peatlands.Methods Here,we investigated total phenols contents(TPC)and total tannins contents in leaves of 11 plant species in 18 peatlands of the Great Hing’an Mountains area in northeastern China,and examined their variations with leaf N and phosphorus(P)and underlying mechanisms.Important Findings Shrubs had higher TPC than graminoids,indicating less C allocation to defense and less uptake of organic N in faster-growing and nonmycorrhizal graminoids than in slower-growing and mycorrhizal shrubs.For shrubs,leaf TPC decreased with increasing N contents but was not influenced by changing leaf phosphorus(P)contents,which suggested that shrubs would reduce the C investment for defense with increasing N availability.Differently,leaf TPC of graminoids increased with leaf N contents and decreased with leaf P contents.As graminoids are more N-limited and less P-limited,we inferred that graminoids would increase the defensive C investment under increased nutrient availability.We concluded that shrubs would invest more C in growth than in defense with increasing N availability,but it was just opposite for graminoids,which might be an important mechanism to explain the resource competition and encroachment of shrubs in boreal peatlands in the context of climate warming and ever-increasing N deposition.展开更多
基金Project supported by the National Basic Research Program(973)of China(No.2012CB315906)
文摘Moving target defense （MT_D） is a novel way to alter the asymmetric situation of attacks and defenses, and a lot of MTD studies have been carried out recently. However, relevant analysis for the defense mechanism of the MTD technology is still absent. In this paper, we analyze the defense mechanism of MTD technology in two dimensions. First, we present a new defense model named MP2R to describe the proactivity and effect of MTD technology intuitively. Second, we use the incomplete information dynamic game theory to verify the proactivity and effect of MTD technology. Specifically, we model the interaction between a defender who equips a server with different types of MTD techniques and a visitor who can be a user or an attacker, and analyze the equilibria and their conditions for these models. Then, we take an existing incomplete information dynamic game model for traditional defense and its equilibrium result as baseline for comparison, to validate the proactivity and effect of MTD technology. We also identify the factors that will influence the proactivity and effectiveness of the MTD approaches. This work gives theoretical support for understanding the defense process and defense mechanism of MTD technology and provides suggestions to improve the effectiveness of MTD approaches.
基金supported by the National Key Research and Development Program of China(2016YFA0600802)the National Natural Science Foundation of China(41730855,41522301)+1 种基金the Open Project Foundation in Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains,Ministry of Education(GPES201904)supported by the 11th Recruitment Program of Global Experts(the Thousand Talents Plan)for Young Professionals granted by the central budget of China.
文摘Aims Climate warming and increasing nitrogen(N)deposition have influenced plant nutrient status and thus plant carbon(C)fixation and vegetation composition in boreal peatlands.Phenols,which are secondary metabolites in plants for defense and adaptation,also play important roles in regulating peatland C dynamics due to their anti-decomposition properties.However,how the phenolic levels of different functional types of plants vary depending on nutrient availability remain unclear in boreal peatlands.Methods Here,we investigated total phenols contents(TPC)and total tannins contents in leaves of 11 plant species in 18 peatlands of the Great Hing’an Mountains area in northeastern China,and examined their variations with leaf N and phosphorus(P)and underlying mechanisms.Important Findings Shrubs had higher TPC than graminoids,indicating less C allocation to defense and less uptake of organic N in faster-growing and nonmycorrhizal graminoids than in slower-growing and mycorrhizal shrubs.For shrubs,leaf TPC decreased with increasing N contents but was not influenced by changing leaf phosphorus(P)contents,which suggested that shrubs would reduce the C investment for defense with increasing N availability.Differently,leaf TPC of graminoids increased with leaf N contents and decreased with leaf P contents.As graminoids are more N-limited and less P-limited,we inferred that graminoids would increase the defensive C investment under increased nutrient availability.We concluded that shrubs would invest more C in growth than in defense with increasing N availability,but it was just opposite for graminoids,which might be an important mechanism to explain the resource competition and encroachment of shrubs in boreal peatlands in the context of climate warming and ever-increasing N deposition.
