Efficient spectrum resource allocation in wireless heterogeneous networks is important for improving the system throughput and guaranteeing the user's Quality-of-Service(QoS).In this paper,we propose an enhanced a...Efficient spectrum resource allocation in wireless heterogeneous networks is important for improving the system throughput and guaranteeing the user's Quality-of-Service(QoS).In this paper,we propose an enhanced algorithm for spectrum resource allocation in heterogeneous networks.First,the bandwidth of each user is determined by the user's rate demand and the channel state.Second,graph theory is enhanced and used to improve the spectrum efficiency.Third,spectrum resource is dynamically split between macrocell and femtocells with the changes of users' conditions.Our simulation results show that the proposed algorithm improves the system throughput significantly and also guarantees the fairness for the users.展开更多
Heterogeneous mean-field theory is commonly used methodology to study dynamical processes on complex networks,such as epidemic spreading and phase transitions in spin models.In this paper,we propose an improved hetero...Heterogeneous mean-field theory is commonly used methodology to study dynamical processes on complex networks,such as epidemic spreading and phase transitions in spin models.In this paper,we propose an improved heterogeneous mean-field theory for studying the Ising model on complex networks.Our method shows a more accurate prediction in the critical temperature of the Ising model than the previous heterogeneous mean-field theory.The theoretical results are validated by extensive Monte Carlo simulations in various types of networks.展开更多
Using molecular dynamics with embedded-atom-type interatomicpotentials, we simulated the melting behavior of a spherical Ag3055 cluster coated with Ni. The semi-coherent Ag/Ni interface formed at low temperatures acts...Using molecular dynamics with embedded-atom-type interatomicpotentials, we simulated the melting behavior of a spherical Ag3055 cluster coated with Ni. The semi-coherent Ag/Ni interface formed at low temperatures acts as an effective barrier against the surface melting and leads to a substantial superheating of the Ag cluster. The melting point was found to be about 100 K above the equilibrium melting point of the bulk Ag crystal (1230 K±15 K) and about 290 K above that (1040 K) of the free Ag3055 cluster. A superheating of 70 K was observed in the high-temperature differential scanning calorimetry measurement for Ag particles with a mean size of 30 nm embedded in Ni matrix prepared by means of melt-spinning. Melting is initiated locally at the defective interfacial area and then propagates inwards, suggesting a heterogeneously nucleated melting event at the Ag/Ni interface.展开更多
基金supported in part by National Natural Science Foundation(61231008)Natural Science Foundation of Shannxi Province(2015JQ6248)+1 种基金National S&T Major Project(2012ZX03003005-005)the 111 Project (B08038)
文摘Efficient spectrum resource allocation in wireless heterogeneous networks is important for improving the system throughput and guaranteeing the user's Quality-of-Service(QoS).In this paper,we propose an enhanced algorithm for spectrum resource allocation in heterogeneous networks.First,the bandwidth of each user is determined by the user's rate demand and the channel state.Second,graph theory is enhanced and used to improve the spectrum efficiency.Third,spectrum resource is dynamically split between macrocell and femtocells with the changes of users' conditions.Our simulation results show that the proposed algorithm improves the system throughput significantly and also guarantees the fairness for the users.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11875069,11405001the Key Scientific Research Fund of Anhui Provincial Education Department under Grant No.KJ2019A0781
文摘Heterogeneous mean-field theory is commonly used methodology to study dynamical processes on complex networks,such as epidemic spreading and phase transitions in spin models.In this paper,we propose an improved heterogeneous mean-field theory for studying the Ising model on complex networks.Our method shows a more accurate prediction in the critical temperature of the Ising model than the previous heterogeneous mean-field theory.The theoretical results are validated by extensive Monte Carlo simulations in various types of networks.
基金This work was supported by the Ministry of Science and Technology of China (Grant No. 1999064505)the National Natural Science Foundation of China (Grant Nos. 59801011, 59931030 and 59841004) the Max-Planck-Society of Germany.
文摘Using molecular dynamics with embedded-atom-type interatomicpotentials, we simulated the melting behavior of a spherical Ag3055 cluster coated with Ni. The semi-coherent Ag/Ni interface formed at low temperatures acts as an effective barrier against the surface melting and leads to a substantial superheating of the Ag cluster. The melting point was found to be about 100 K above the equilibrium melting point of the bulk Ag crystal (1230 K±15 K) and about 290 K above that (1040 K) of the free Ag3055 cluster. A superheating of 70 K was observed in the high-temperature differential scanning calorimetry measurement for Ag particles with a mean size of 30 nm embedded in Ni matrix prepared by means of melt-spinning. Melting is initiated locally at the defective interfacial area and then propagates inwards, suggesting a heterogeneously nucleated melting event at the Ag/Ni interface.
