The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying coevolution.Avian brood parasitism reduces the reproductive success of hosts,and thus,hosts ...The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying coevolution.Avian brood parasitism reduces the reproductive success of hosts,and thus,hosts have evolved anti-parasitic strategies,such as rejecting parasitic eggs and adopting aggressive nest defense strategies,to avoid the cost brought on by brood parasitism.To test whether host anti-parasitic strategies are adjusted with the risk of being parasitized when the breeding seasons of brood parasites and hosts are not synchronous,we conducted a field experiment assessing nest defense and egg recognition behaviors of the Isabelline Shrike(Lanius isabellinus),a host of the Common Cuckoo(Cuculus canorus).In the local area,the host Isabelline Shrike begins to breed in April,whereas the summer migratory Common Cuckoo migrates to the local area in May and begins to lay parasitic eggs.Results showed that nest defense behaviors of the Isabelline Shrike increases significantly after cuckoo arrival,showing higher aggressiveness to cuckoo dummies,with no significant difference in attack rates among cuckoo,sparrowhawk and dove dummies,but their egg rejection did not change significantly.These results imply that Isabelline Shrikes may adjust their nest defense behavior,but not egg rejection behavior,with seasonality.展开更多
As a core component of the network,web applications have become one of the preferred targets for attackers because the static configuration of web applications simplifies the exploitation of vulnerabilities by attacke...As a core component of the network,web applications have become one of the preferred targets for attackers because the static configuration of web applications simplifies the exploitation of vulnerabilities by attackers.Although the moving target defense(MTD)has been proposed to increase the attack difficulty for the attackers,there is no solo approach can cope with different attacks;in addition,it is impossible to implement all these approaches simultaneously due to the resource limitation.Thus,the selection of an optimal defense strategy based on MTD has become the focus of research.In general,the confrontation of two players in the security domain is viewed as a stochastic game,and the reward matrices are known to both players.However,in a real security confrontation,this scenario represents an incomplete information game.Each player can only observe the actions performed by the opponent,and the observed actions are not completely accurate.To accurately describe the attacker’s reward function to reach the Nash equilibrium,this work simulated and updated the strategy selection distribution of the attacker by observing and investigating the strategy selection history of the attacker.Next,the possible rewards of the attacker in each confrontation via the observation matrix were corrected.On this basis,the Nash-Q learning algorithm with reward quantification was proposed to select the optimal strategy.Moreover,the performances of the Minimax-Q learning algorithm and Naive-Q learning algorithm were compared and analyzed in the MTD environment.Finally,the experimental results showed that the strategy selection algorithm can enable defenders to select a more reasonable defensive strategy and achieve the maximum possible reward.展开更多
<strong>Introduction</strong><strong>:</strong> The key to success is finding the perfect mixture of tactical patterns and sudden breaks of them, which depends on the behavior of the opponent t...<strong>Introduction</strong><strong>:</strong> The key to success is finding the perfect mixture of tactical patterns and sudden breaks of them, which depends on the behavior of the opponent team and is not easy to estimate by just watching matches. According to the specific tactical team behavior of “attack vs. defense” professional football matches are investigated based on a simulation approach, professional football matches are investigated according to the specific tactical team behavior of “attack vs. defense.” <strong>Methods:</strong> The formation patterns of all the sample games are categorized by SOCCER<span style="white-space:nowrap;">©</span> for defense and attack. Monte Carlo-Simulation can evaluate the mathematical, optimal strategy. The interaction simulation between attack and defense shows optimal flexibility rates for both tactical groups. <strong>Approach: </strong>A simulation approach based on 40 position data sets of the 2014/15 German Bundesliga has been conducted to analyze and optimize such strategic team behavior in professional soccer. <strong>Results:</strong> The results revealed that both attack and defense have optimal planning rates to be more successful. The more complex the success indicator, the more successful attacking player groups get. The results also show that defensive player groups always succeed in attacking groups below a specific planning rate value.<strong> Conclusion:</strong> Groups are always succeeding. The simulation-based position data analysis shows successful strategic behavior patterns for attack and defense. Attacking player groups need very high flexibility to be successful (stay in ball possession). In contrast, defensive player groups only need to be below a defined flexibility rate to be guaranteed more success.展开更多
基金funded by the National Natural Science Foundation of China (Nos. 31970427 and 32270526 to WL)。
文摘The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying coevolution.Avian brood parasitism reduces the reproductive success of hosts,and thus,hosts have evolved anti-parasitic strategies,such as rejecting parasitic eggs and adopting aggressive nest defense strategies,to avoid the cost brought on by brood parasitism.To test whether host anti-parasitic strategies are adjusted with the risk of being parasitized when the breeding seasons of brood parasites and hosts are not synchronous,we conducted a field experiment assessing nest defense and egg recognition behaviors of the Isabelline Shrike(Lanius isabellinus),a host of the Common Cuckoo(Cuculus canorus).In the local area,the host Isabelline Shrike begins to breed in April,whereas the summer migratory Common Cuckoo migrates to the local area in May and begins to lay parasitic eggs.Results showed that nest defense behaviors of the Isabelline Shrike increases significantly after cuckoo arrival,showing higher aggressiveness to cuckoo dummies,with no significant difference in attack rates among cuckoo,sparrowhawk and dove dummies,but their egg rejection did not change significantly.These results imply that Isabelline Shrikes may adjust their nest defense behavior,but not egg rejection behavior,with seasonality.
基金This paper is supported by the National Key R&D Program of China(2017YFB0802703)the National Nature Science Foundation of China(61602052).
文摘As a core component of the network,web applications have become one of the preferred targets for attackers because the static configuration of web applications simplifies the exploitation of vulnerabilities by attackers.Although the moving target defense(MTD)has been proposed to increase the attack difficulty for the attackers,there is no solo approach can cope with different attacks;in addition,it is impossible to implement all these approaches simultaneously due to the resource limitation.Thus,the selection of an optimal defense strategy based on MTD has become the focus of research.In general,the confrontation of two players in the security domain is viewed as a stochastic game,and the reward matrices are known to both players.However,in a real security confrontation,this scenario represents an incomplete information game.Each player can only observe the actions performed by the opponent,and the observed actions are not completely accurate.To accurately describe the attacker’s reward function to reach the Nash equilibrium,this work simulated and updated the strategy selection distribution of the attacker by observing and investigating the strategy selection history of the attacker.Next,the possible rewards of the attacker in each confrontation via the observation matrix were corrected.On this basis,the Nash-Q learning algorithm with reward quantification was proposed to select the optimal strategy.Moreover,the performances of the Minimax-Q learning algorithm and Naive-Q learning algorithm were compared and analyzed in the MTD environment.Finally,the experimental results showed that the strategy selection algorithm can enable defenders to select a more reasonable defensive strategy and achieve the maximum possible reward.
文摘<strong>Introduction</strong><strong>:</strong> The key to success is finding the perfect mixture of tactical patterns and sudden breaks of them, which depends on the behavior of the opponent team and is not easy to estimate by just watching matches. According to the specific tactical team behavior of “attack vs. defense” professional football matches are investigated based on a simulation approach, professional football matches are investigated according to the specific tactical team behavior of “attack vs. defense.” <strong>Methods:</strong> The formation patterns of all the sample games are categorized by SOCCER<span style="white-space:nowrap;">©</span> for defense and attack. Monte Carlo-Simulation can evaluate the mathematical, optimal strategy. The interaction simulation between attack and defense shows optimal flexibility rates for both tactical groups. <strong>Approach: </strong>A simulation approach based on 40 position data sets of the 2014/15 German Bundesliga has been conducted to analyze and optimize such strategic team behavior in professional soccer. <strong>Results:</strong> The results revealed that both attack and defense have optimal planning rates to be more successful. The more complex the success indicator, the more successful attacking player groups get. The results also show that defensive player groups always succeed in attacking groups below a specific planning rate value.<strong> Conclusion:</strong> Groups are always succeeding. The simulation-based position data analysis shows successful strategic behavior patterns for attack and defense. Attacking player groups need very high flexibility to be successful (stay in ball possession). In contrast, defensive player groups only need to be below a defined flexibility rate to be guaranteed more success.
