针对传统的基于栅格图的拓扑分析方法存在实时性差和理解困难,提出了一种新颖的基于连通度的拓扑分析法(topological analysis based on connection,TAC),该方法通过定义“连通度”的概念,改进通常的“障碍物膨胀法”,使之实现实时计算...针对传统的基于栅格图的拓扑分析方法存在实时性差和理解困难,提出了一种新颖的基于连通度的拓扑分析法(topological analysis based on connection,TAC),该方法通过定义“连通度”的概念,改进通常的“障碍物膨胀法”,使之实现实时计算和对栅格图较好的拓扑理解。在此基础上,进一步提出了综合考虑几何与拓扑信息的探测策略,提高了机器人完成任务的效率。仿真实验及在ATU-Ⅱ机器人上的应用证明了策略的有效性。展开更多
In order to transmit the secure message, a deterministic secure quantum direct communication protocol which was called ＂Ping-pong＂ protocol was proposed by Bostrrm and Felbinger [Bostrom K, et al. Phys Rev Lett, 200...In order to transmit the secure message, a deterministic secure quantum direct communication protocol which was called ＂Ping-pong＂ protocol was proposed by Bostrrm and Felbinger [Bostrom K, et al. Phys Rev Lett, 2002, 89： 187902]. But the protocol was proved very vulnerable, and can be attacked by an eavesdropper. An improved ＂Ping-pong＂ protocol is presented to overcome the problem. The GHZ state particles are used to detect eavesdroppers, and the classical XOR operation which serves as a one-time-pad is used to ensure the security of the protocol. During the security analysis, the method of the entropy theory is introduced, and three detection strategies are compared quantitatively by using the constraint between the information which an eavesdropper can obtain and the interference introduced. If the eavesdropper gets the full information, the detection rate of the original ＂Ping-pong＂ protocol is 50%; the detection rate of the second protocol which used two particles of EPR pair as detection particles is also 50%; and the detection rate of the presented protocol is 75%. In the end, the security of the pro-posed protocol is discussed. The analysis results show that the improved ＂Ping-pong＂ protocol in this paper is more secure than the other two.展开更多
Personality can play a large role in dispersal decisions, influencing how each individual estimates and values ex- pected costs versus benefits of ventnring out to explore the unknown. We contrast the impact of persis...Personality can play a large role in dispersal decisions, influencing how each individual estimates and values ex- pected costs versus benefits of ventnring out to explore the unknown. We contrast the impact of persistence on fitness using deci- sion theory models to examine the relative success of prospecting movement （which is a widespread behavior used by animals to explore available breeding habitat before determining where to settle） in different landscapes among individuals with different personalities. While evaluating trends in the costs and benefits of movement we provide a quantifiable measure of the impacts of relative tenacity in prospecting behavior on fitness gains/losses. Our model results predict that, regardless of landscape composi- tion, individuals with greater tenacity in prospecting strategy have reduced fitness gains relative to individuals who are more willing to both initiate novel strategies, but then also abandon the new strategy rapidly if initial search does not seem fruitful. We show that fitness gains from choosing an appropriate prospecting strategy （i.e. abandoning poor habitat or staying in rich habitat） can be very high, indicating a potentially large influence from personality on fitness. Importantly, the model predicts that relative fitness gains are highly dependent on the availability of high quality habitat in the landscape, even if the difference under varying fitness outcomes between poor and rich habitat was substantial展开更多
文摘针对传统的基于栅格图的拓扑分析方法存在实时性差和理解困难,提出了一种新颖的基于连通度的拓扑分析法(topological analysis based on connection,TAC),该方法通过定义“连通度”的概念,改进通常的“障碍物膨胀法”,使之实现实时计算和对栅格图较好的拓扑理解。在此基础上,进一步提出了综合考虑几何与拓扑信息的探测策略,提高了机器人完成任务的效率。仿真实验及在ATU-Ⅱ机器人上的应用证明了策略的有效性。
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20060013007)the Natural Science Foundation of Beijing (Grant No. 4092029)the National Natural Science Foundation of China (Grant No. 60873001)
文摘In order to transmit the secure message, a deterministic secure quantum direct communication protocol which was called ＂Ping-pong＂ protocol was proposed by Bostrrm and Felbinger [Bostrom K, et al. Phys Rev Lett, 2002, 89： 187902]. But the protocol was proved very vulnerable, and can be attacked by an eavesdropper. An improved ＂Ping-pong＂ protocol is presented to overcome the problem. The GHZ state particles are used to detect eavesdroppers, and the classical XOR operation which serves as a one-time-pad is used to ensure the security of the protocol. During the security analysis, the method of the entropy theory is introduced, and three detection strategies are compared quantitatively by using the constraint between the information which an eavesdropper can obtain and the interference introduced. If the eavesdropper gets the full information, the detection rate of the original ＂Ping-pong＂ protocol is 50%; the detection rate of the second protocol which used two particles of EPR pair as detection particles is also 50%; and the detection rate of the presented protocol is 75%. In the end, the security of the pro-posed protocol is discussed. The analysis results show that the improved ＂Ping-pong＂ protocol in this paper is more secure than the other two.
文摘Personality can play a large role in dispersal decisions, influencing how each individual estimates and values ex- pected costs versus benefits of ventnring out to explore the unknown. We contrast the impact of persistence on fitness using deci- sion theory models to examine the relative success of prospecting movement （which is a widespread behavior used by animals to explore available breeding habitat before determining where to settle） in different landscapes among individuals with different personalities. While evaluating trends in the costs and benefits of movement we provide a quantifiable measure of the impacts of relative tenacity in prospecting behavior on fitness gains/losses. Our model results predict that, regardless of landscape composi- tion, individuals with greater tenacity in prospecting strategy have reduced fitness gains relative to individuals who are more willing to both initiate novel strategies, but then also abandon the new strategy rapidly if initial search does not seem fruitful. We show that fitness gains from choosing an appropriate prospecting strategy （i.e. abandoning poor habitat or staying in rich habitat） can be very high, indicating a potentially large influence from personality on fitness. Importantly, the model predicts that relative fitness gains are highly dependent on the availability of high quality habitat in the landscape, even if the difference under varying fitness outcomes between poor and rich habitat was substantial
