A hybrid identification model based on multilayer artificial neural networks(ANNs) and particle swarm optimization(PSO) algorithm is developed to improve the simultaneous identification efficiency of thermal conductiv...A hybrid identification model based on multilayer artificial neural networks(ANNs) and particle swarm optimization(PSO) algorithm is developed to improve the simultaneous identification efficiency of thermal conductivity and effective absorption coefficient of semitransparent materials.For the direct model,the spherical harmonic method and the finite volume method are used to solve the coupled conduction-radiation heat transfer problem in an absorbing,emitting,and non-scattering 2D axisymmetric gray medium in the background of laser flash method.For the identification part,firstly,the temperature field and the incident radiation field in different positions are chosen as observables.Then,a traditional identification model based on PSO algorithm is established.Finally,multilayer ANNs are built to fit and replace the direct model in the traditional identification model to speed up the identification process.The results show that compared with the traditional identification model,the time cost of the hybrid identification model is reduced by about 1 000 times.Besides,the hybrid identification model remains a high level of accuracy even with measurement errors.展开更多
E-mail communication network evolution model based on user information propagation is studied. First, mathematical representation of weighted e-mail communication network is proposed, and network center parameters of ...E-mail communication network evolution model based on user information propagation is studied. First, mathematical representation of weighted e-mail communication network is proposed, and network center parameters of Enron dataset and the distribution of node degree and strength are analyzed. Then, some rules of e-mail communication network evolution are found. Second, the model of e-mail information propagation is described, and e-mail communication network evolution model based on user information propagation is proposed. Lastly, the simulation proves the correctness of the distribution characteristic of degree and strength of the model proposed and then verifies that the model proposed is closer to the real situation of e-mail communication network through parameter comparison. This research provides the basis for other researches on social network evolution and data communication.展开更多
An evolution model of KAD Dynamic Model Network(KDMN) is proposed to study the reason of hot node and simulate the process of network evolution based on node behavior from a holistic perspective.First,some symbols and...An evolution model of KAD Dynamic Model Network(KDMN) is proposed to study the reason of hot node and simulate the process of network evolution based on node behavior from a holistic perspective.First,some symbols and meanings are introduced to describe nodes relationship and network states at a time step.Second,some evolution rules for network are formulated when node behaviors of join,exit,routing table update,data retrieval and content index distribution happen with different contextual scene in KAD network.In addition,a lightweight simulator is designed to implement the KDMN model.Moreover,an example of how to use the simulator to simulate the network changes in order to observe the result is described in detail.Finally,the KDMN is applied to analyze the reason for the formation of hot nodes in the BT and eMule network in the experiment.The different evolution principles of local priority,global priority and hybrid random are adopted based on the provision of network protocol of BT and eMule.The result of this experiment demonstrates that there are some hot nodes exist in the KAD network.However,the principle of hybrid random can effectively alleviate the phenomenon that a node is widely linked with others compared with global and local priority.展开更多
基金supported by the Fundamental Research Funds for the Central Universities (No.3122020072)the Multi-investment Project of Tianjin Applied Basic Research(No.23JCQNJC00250)。
文摘A hybrid identification model based on multilayer artificial neural networks(ANNs) and particle swarm optimization(PSO) algorithm is developed to improve the simultaneous identification efficiency of thermal conductivity and effective absorption coefficient of semitransparent materials.For the direct model,the spherical harmonic method and the finite volume method are used to solve the coupled conduction-radiation heat transfer problem in an absorbing,emitting,and non-scattering 2D axisymmetric gray medium in the background of laser flash method.For the identification part,firstly,the temperature field and the incident radiation field in different positions are chosen as observables.Then,a traditional identification model based on PSO algorithm is established.Finally,multilayer ANNs are built to fit and replace the direct model in the traditional identification model to speed up the identification process.The results show that compared with the traditional identification model,the time cost of the hybrid identification model is reduced by about 1 000 times.Besides,the hybrid identification model remains a high level of accuracy even with measurement errors.
基金sponsored by the National Natural Science Foundation of China under grant number No. 61100008, 61201084the China Postdoctoral Science Foundation under Grant No. 2013M541346+3 种基金Heilongiiang Postdoctoral Special Fund (Postdoctoral Youth Talent Program) under Grant No. LBH-TZ0504Heilongjiang Postdoctoral Fund under Grant No. LBH-Z13058the Natural Science Foundation of Heilongjiang Province of China under Grant No. QC2015076Funds for the Central Universities of China under grant number HEUCF100602
文摘E-mail communication network evolution model based on user information propagation is studied. First, mathematical representation of weighted e-mail communication network is proposed, and network center parameters of Enron dataset and the distribution of node degree and strength are analyzed. Then, some rules of e-mail communication network evolution are found. Second, the model of e-mail information propagation is described, and e-mail communication network evolution model based on user information propagation is proposed. Lastly, the simulation proves the correctness of the distribution characteristic of degree and strength of the model proposed and then verifies that the model proposed is closer to the real situation of e-mail communication network through parameter comparison. This research provides the basis for other researches on social network evolution and data communication.
文摘An evolution model of KAD Dynamic Model Network(KDMN) is proposed to study the reason of hot node and simulate the process of network evolution based on node behavior from a holistic perspective.First,some symbols and meanings are introduced to describe nodes relationship and network states at a time step.Second,some evolution rules for network are formulated when node behaviors of join,exit,routing table update,data retrieval and content index distribution happen with different contextual scene in KAD network.In addition,a lightweight simulator is designed to implement the KDMN model.Moreover,an example of how to use the simulator to simulate the network changes in order to observe the result is described in detail.Finally,the KDMN is applied to analyze the reason for the formation of hot nodes in the BT and eMule network in the experiment.The different evolution principles of local priority,global priority and hybrid random are adopted based on the provision of network protocol of BT and eMule.The result of this experiment demonstrates that there are some hot nodes exist in the KAD network.However,the principle of hybrid random can effectively alleviate the phenomenon that a node is widely linked with others compared with global and local priority.
