Mobile sensor nodes such as hopping sensors are of critical importance in data collection.However,the occurrence of sensing holes is unavoidable due to the energy limitation of the nodes.Thus,it is evident that the re...Mobile sensor nodes such as hopping sensors are of critical importance in data collection.However,the occurrence of sensing holes is unavoidable due to the energy limitation of the nodes.Thus,it is evident that the relocation of mobile sensors is the most desirable method to recover the sensing holes.The previous research conducted by the authors so far demonstrated the most realistic hopping sensor relocation scheme,which is suitable for the distributed environment.In previous studies,the cluster header plays an essential role in detecting the sensing hole and requesting the neighboring cluster to recover the sensing hole that occurred in the sensor node.However,the limitations of the cluster header in the previously proposed relocation protocol are not fully considered.Because the cluster header jumps more frequently than non-header nodes,its energy con-sumption is relatively high compared to other nodes.Therefore,it is most likely to lead to header node failure and can lead to data loss on the network.In this paper,the jumping ability and energy consumption of the cluster header are seriously considered.Additional ability to replace cluster headers in case of failure is also implemented.Simulation results show that the data collection time can be further increased,which demonstrates the validity of the proposed algorithms.展开更多
Based on the time dependent mild slope equation including the effect of wave energy dissipation, an expression for the energy dissipation factor is derived in conjunction with the wave energy balance equation, and the...Based on the time dependent mild slope equation including the effect of wave energy dissipation, an expression for the energy dissipation factor is derived in conjunction with the wave energy balance equation, and then a practical method for the simulation of wave height and wave set-up in nearshore regions is presented. The variation of the complex wave amplitude is numerically simulated by use of the parabolic mild slope equation including the effect of wave energy dissipation due to wave breaking. The components of wave radiation stress are calculated subsequently by new expressions for them according to the obtained complex wave amplitude, and then the depth-averaged equation is applied to the calculation of wave set-up due to wave breaking. Numerical results are in good agreement with experimental data,showing that the expression for the energy dissipation factor is reasonable and that the new method is effective for the simulation of wave set-up due to wave breaking in nearshore regions.展开更多
In order to investigate the fatigue performance ofFrench high modulus asphalt concrete and the correlationbetween Burger＇s parameters and fatigue life, the virtualmodel of asphalt mixture trapezoidal specimen in the ...In order to investigate the fatigue performance ofFrench high modulus asphalt concrete and the correlationbetween Burger＇s parameters and fatigue life, the virtualmodel of asphalt mixture trapezoidal specimen in the two-pointbending fatigue test was constructed in discrement elementsoftware PFC3D. The initial stiffness and the maximum stresswhen the specimen reached fatigue were calculated. Throughthe comparison between virtual and single field fatigue testcurves, the credibility of simulation in DEM was verified.Then, the impacts of top controlled displacement and Burger＇sparameters （ El, E2, η1, η2） on the fatigue life of the specimenwere explored. The simulation results indicate that themaximum stress increases with the increase in the topcontrolled displacement. With the increase of E1 and thedecrease of E2 in Burger＇s model, the modulus of the asphaltbinder increases, and the fatigue performance of the asphaltmixture enhances, η1 and η22 have limited influence on fatiguelife compared with El and E2.展开更多
基金supported by Incheon National University Research Grant in 2020(2020–0437)。
文摘Mobile sensor nodes such as hopping sensors are of critical importance in data collection.However,the occurrence of sensing holes is unavoidable due to the energy limitation of the nodes.Thus,it is evident that the relocation of mobile sensors is the most desirable method to recover the sensing holes.The previous research conducted by the authors so far demonstrated the most realistic hopping sensor relocation scheme,which is suitable for the distributed environment.In previous studies,the cluster header plays an essential role in detecting the sensing hole and requesting the neighboring cluster to recover the sensing hole that occurred in the sensor node.However,the limitations of the cluster header in the previously proposed relocation protocol are not fully considered.Because the cluster header jumps more frequently than non-header nodes,its energy con-sumption is relatively high compared to other nodes.Therefore,it is most likely to lead to header node failure and can lead to data loss on the network.In this paper,the jumping ability and energy consumption of the cluster header are seriously considered.Additional ability to replace cluster headers in case of failure is also implemented.Simulation results show that the data collection time can be further increased,which demonstrates the validity of the proposed algorithms.
基金This subject was financially supported by the National Natural Science Foundation of China (Grant No. 59839330 and No. 59979025)
文摘Based on the time dependent mild slope equation including the effect of wave energy dissipation, an expression for the energy dissipation factor is derived in conjunction with the wave energy balance equation, and then a practical method for the simulation of wave height and wave set-up in nearshore regions is presented. The variation of the complex wave amplitude is numerically simulated by use of the parabolic mild slope equation including the effect of wave energy dissipation due to wave breaking. The components of wave radiation stress are calculated subsequently by new expressions for them according to the obtained complex wave amplitude, and then the depth-averaged equation is applied to the calculation of wave set-up due to wave breaking. Numerical results are in good agreement with experimental data,showing that the expression for the energy dissipation factor is reasonable and that the new method is effective for the simulation of wave set-up due to wave breaking in nearshore regions.
基金The National Natural Science Foundation of China(No.51378121)
文摘In order to investigate the fatigue performance ofFrench high modulus asphalt concrete and the correlationbetween Burger＇s parameters and fatigue life, the virtualmodel of asphalt mixture trapezoidal specimen in the two-pointbending fatigue test was constructed in discrement elementsoftware PFC3D. The initial stiffness and the maximum stresswhen the specimen reached fatigue were calculated. Throughthe comparison between virtual and single field fatigue testcurves, the credibility of simulation in DEM was verified.Then, the impacts of top controlled displacement and Burger＇sparameters （ El, E2, η1, η2） on the fatigue life of the specimenwere explored. The simulation results indicate that themaximum stress increases with the increase in the topcontrolled displacement. With the increase of E1 and thedecrease of E2 in Burger＇s model, the modulus of the asphaltbinder increases, and the fatigue performance of the asphaltmixture enhances, η1 and η22 have limited influence on fatiguelife compared with El and E2.
