Collision avoidance decision-making models of multiple agents in virtual driving environment are studied. Based on the behavioral characteristics and hierarchical structure of the collision avoidance decision-making i...Collision avoidance decision-making models of multiple agents in virtual driving environment are studied. Based on the behavioral characteristics and hierarchical structure of the collision avoidance decision-making in real life driving, delphi approach and mathematical statistics method are introduced to construct pair-wise comparison judgment matrix of collision avoidance decision choices to each collision situation. Analytic hierarchy process （AHP） is adopted to establish the agents＇ collision avoidance decision-making model. To simulate drivers＇ characteristics, driver factors are added to categorize driving modes into impatient mode, normal mode, and the cautious mode. The results show that this model can simulate human＇s thinking process, and the agents in the virtual environment can deal with collision situations and make decisions to avoid collisions without intervention. The model can also reflect diversity and uncertainly of real life driving behaviors, and solves the multi-objective, multi-choice ranking priority problem in multi-vehicle collision scenarios. This collision avoidance model of multi-agents model is feasible and effective, and can provide richer and closer-to-life virtual scene for driving simulator, reflecting real-life traffic environment more truly, this model can also promote the practicality of driving simulator.展开更多
While remote trust attestation is a useful concept to detect unauthorized changes to software, the current mechanism only ensures authenticity at the start of the operating system and cannot ensure the action of runni...While remote trust attestation is a useful concept to detect unauthorized changes to software, the current mechanism only ensures authenticity at the start of the operating system and cannot ensure the action of running software. Our approach is to use a behavior-based monitoring agent to make remote attestation more flexible, dynamic, and trustworthy. This approach was mostly made possible by extensive use of process information which is readily available in Unix. We also made use of a behavior tree to effectively record predictable behaviors of each process. In this paper, we primarily focus on building a prototype implementation of such framework, presenting one example built on it, successfully find potential security risks in the run time of a ftp program and then evaluate the performance of this model.展开更多
Poly（L-lactide）（PLLA）/pristine vermiculite nanocomposites were prepared by melt blending in a twin-screw extruder, and the detailed information of vermiculite dispersion state and effect of vermiculite on thermal ...Poly（L-lactide）（PLLA）/pristine vermiculite nanocomposites were prepared by melt blending in a twin-screw extruder, and the detailed information of vermiculite dispersion state and effect of vermiculite on thermal and mechanical properties were systematically studied. The results show that the dispersion of vermiculite in the matrix is quite well when the loading content does not exceed 3 wt%. Pristine vermiculite can obviously improve the melt-crystallization temperature during the nonisothermal crystallization. Both crystallization time span and spherulitic size of PLLA decrease with the increasing amount of vermiculite under isothermal crystallization condition by enhancing the primary nucleation of PLLA. And the adding vermiculite can also improve the tensile modulus and Izod impact strength of PLLA. The intrinsic mechanism for the nucleating effect of vermiculite on PLLA is proposed to be the epitaxial crystallization and specific interaction between vermiculite and PLLA.展开更多
基金supported by National Basic Research Program (973 Program,No.2004CB719402)National Natural Science Foundation of China (No.60736019)Natural Science Foundation of Zhejiang Province, China(No.Y105430).
文摘Collision avoidance decision-making models of multiple agents in virtual driving environment are studied. Based on the behavioral characteristics and hierarchical structure of the collision avoidance decision-making in real life driving, delphi approach and mathematical statistics method are introduced to construct pair-wise comparison judgment matrix of collision avoidance decision choices to each collision situation. Analytic hierarchy process （AHP） is adopted to establish the agents＇ collision avoidance decision-making model. To simulate drivers＇ characteristics, driver factors are added to categorize driving modes into impatient mode, normal mode, and the cautious mode. The results show that this model can simulate human＇s thinking process, and the agents in the virtual environment can deal with collision situations and make decisions to avoid collisions without intervention. The model can also reflect diversity and uncertainly of real life driving behaviors, and solves the multi-objective, multi-choice ranking priority problem in multi-vehicle collision scenarios. This collision avoidance model of multi-agents model is feasible and effective, and can provide richer and closer-to-life virtual scene for driving simulator, reflecting real-life traffic environment more truly, this model can also promote the practicality of driving simulator.
基金Supported by the National Natural Science Foun-dation of China (90104005 ,60373087 ,60473023)
文摘While remote trust attestation is a useful concept to detect unauthorized changes to software, the current mechanism only ensures authenticity at the start of the operating system and cannot ensure the action of running software. Our approach is to use a behavior-based monitoring agent to make remote attestation more flexible, dynamic, and trustworthy. This approach was mostly made possible by extensive use of process information which is readily available in Unix. We also made use of a behavior tree to effectively record predictable behaviors of each process. In this paper, we primarily focus on building a prototype implementation of such framework, presenting one example built on it, successfully find potential security risks in the run time of a ftp program and then evaluate the performance of this model.
基金financially supported by the National Natural Science Foundation of China(No.21304108)the Science Foundation of China University of Petroleum-Beijing(No.YJRC-2013-142462013BJRC001)
文摘Poly（L-lactide）（PLLA）/pristine vermiculite nanocomposites were prepared by melt blending in a twin-screw extruder, and the detailed information of vermiculite dispersion state and effect of vermiculite on thermal and mechanical properties were systematically studied. The results show that the dispersion of vermiculite in the matrix is quite well when the loading content does not exceed 3 wt%. Pristine vermiculite can obviously improve the melt-crystallization temperature during the nonisothermal crystallization. Both crystallization time span and spherulitic size of PLLA decrease with the increasing amount of vermiculite under isothermal crystallization condition by enhancing the primary nucleation of PLLA. And the adding vermiculite can also improve the tensile modulus and Izod impact strength of PLLA. The intrinsic mechanism for the nucleating effect of vermiculite on PLLA is proposed to be the epitaxial crystallization and specific interaction between vermiculite and PLLA.
