A coalition formation algorithm is presented with limited communication ranges and delays in unknown environment,for the performance of multiple heterogeneous unmanned aerial vehicles(UAVs)in cooperative search and at...A coalition formation algorithm is presented with limited communication ranges and delays in unknown environment,for the performance of multiple heterogeneous unmanned aerial vehicles(UAVs)in cooperative search and attack missions.The mathematic model of coalition formation is built on basis of the minimum attacking time and the minimum coalition size with satisfying resources and simultaneous strikes requirements.A communication protocol based on maximum number of hops is developed to determine the potential coalition members in dynamic network.A multistage sub-optimal coalition formation algorithm(MSOCFA)with polynomial time is established.The performances of MSOCFA and particle swarm optimization(PSO)algorithms are compared in terms of complexity,mission performance and computational time.A complex scenario is deployed to illustrate how the coalitions are formed and validate the feasibility of the MSOCFA.The effect of communication constraints(hop delay and max-hops)on mission performance is studied.The results show that it is beneficial to determine potential coalition members in a wide and deep range over the network in the presence of less delay.However,when the delays are significant,it is more advantageous to determine coalitions from among the immediate neighbors.展开更多
Two different mechanisms have been proposed for the formation of ettringite, i.e. through-solution reaction and topochemical reaction. In this paper, the formation mechanism of secondary ettringite in concrete due to ...Two different mechanisms have been proposed for the formation of ettringite, i.e. through-solution reaction and topochemical reaction. In this paper, the formation mechanism of secondary ettringite in concrete due to sulfate attack was reviewed and analyzed. It was deduced that the formation mechanism of secondary ettringite is mainly by topochemical mechanism. The sample made from AFm (4CaO·Al2O3·CaSO4·12H2O) and Ca (OH)2 was immersed in 5% sodium sulfate at 20℃for 20 days. X-ray diffraction (XRD) was used to analyze the sample. The results verified that the formation mechanism of secondary ettringite should be attributed to topochemical reaction.展开更多
Poorly secured connected objects can compromise the security of an entire company, or even paralyze others. As useful as they are, they can be open doors for computer attacks against the company. To protect themselves...Poorly secured connected objects can compromise the security of an entire company, or even paralyze others. As useful as they are, they can be open doors for computer attacks against the company. To protect themselves, large companies set up expensive infrastructures to analyze the data that circulates inside and outside the company. They install a SOC, a Security Operation Center whose objective is to identify and analyze, using various tools, the level of protection of a company and, if necessary, to alert on vulnerabilities and leaks of security data. However, the attack detection capabilities of traditional systems are based on a base of known signatures. Problem is that it is increasingly rare to have to face threats whose signature is unknown. Artificial intelligence, on the contrary, does not look for fingerprints in the packets carrying the attack, but rather analyzes how these packets are arranged. The objective of this study is to show that the use of artificial intelligence in companies may be low and to show the positive impacts of its use compared to the traditional system used in companies. We also simulate an attack on a system equipped with artificial intelligence to highlight the advantages of AI in a computer attack. This research is important because it highlights the risks that companies expose themselves to by always remaining secure in their systems based on traditional techniques. The aim of this research is to show the advantages that AI offers on cyber security compared to the traditional security system. The expected result is to show the existing issues regarding the rate of use of AI on cybersecurity in Burkina Faso. .展开更多
基金partially sponsored by the Fundamental Research Funds for the Central Universities(No.3102015ZY092)
文摘A coalition formation algorithm is presented with limited communication ranges and delays in unknown environment,for the performance of multiple heterogeneous unmanned aerial vehicles(UAVs)in cooperative search and attack missions.The mathematic model of coalition formation is built on basis of the minimum attacking time and the minimum coalition size with satisfying resources and simultaneous strikes requirements.A communication protocol based on maximum number of hops is developed to determine the potential coalition members in dynamic network.A multistage sub-optimal coalition formation algorithm(MSOCFA)with polynomial time is established.The performances of MSOCFA and particle swarm optimization(PSO)algorithms are compared in terms of complexity,mission performance and computational time.A complex scenario is deployed to illustrate how the coalitions are formed and validate the feasibility of the MSOCFA.The effect of communication constraints(hop delay and max-hops)on mission performance is studied.The results show that it is beneficial to determine potential coalition members in a wide and deep range over the network in the presence of less delay.However,when the delays are significant,it is more advantageous to determine coalitions from among the immediate neighbors.
基金Funded by the National Natural Science Foundation of China (No. 50378092)
文摘Two different mechanisms have been proposed for the formation of ettringite, i.e. through-solution reaction and topochemical reaction. In this paper, the formation mechanism of secondary ettringite in concrete due to sulfate attack was reviewed and analyzed. It was deduced that the formation mechanism of secondary ettringite is mainly by topochemical mechanism. The sample made from AFm (4CaO·Al2O3·CaSO4·12H2O) and Ca (OH)2 was immersed in 5% sodium sulfate at 20℃for 20 days. X-ray diffraction (XRD) was used to analyze the sample. The results verified that the formation mechanism of secondary ettringite should be attributed to topochemical reaction.
文摘Poorly secured connected objects can compromise the security of an entire company, or even paralyze others. As useful as they are, they can be open doors for computer attacks against the company. To protect themselves, large companies set up expensive infrastructures to analyze the data that circulates inside and outside the company. They install a SOC, a Security Operation Center whose objective is to identify and analyze, using various tools, the level of protection of a company and, if necessary, to alert on vulnerabilities and leaks of security data. However, the attack detection capabilities of traditional systems are based on a base of known signatures. Problem is that it is increasingly rare to have to face threats whose signature is unknown. Artificial intelligence, on the contrary, does not look for fingerprints in the packets carrying the attack, but rather analyzes how these packets are arranged. The objective of this study is to show that the use of artificial intelligence in companies may be low and to show the positive impacts of its use compared to the traditional system used in companies. We also simulate an attack on a system equipped with artificial intelligence to highlight the advantages of AI in a computer attack. This research is important because it highlights the risks that companies expose themselves to by always remaining secure in their systems based on traditional techniques. The aim of this research is to show the advantages that AI offers on cyber security compared to the traditional security system. The expected result is to show the existing issues regarding the rate of use of AI on cybersecurity in Burkina Faso. .
