In order to evaluate the impact of off-road terrains on the ride comfort of construction vehicles,a nonlinear dynamic model of the construction vehicles interacting with the terrain deformations is established based o...In order to evaluate the impact of off-road terrains on the ride comfort of construction vehicles,a nonlinear dynamic model of the construction vehicles interacting with the terrain deformations is established based on Matlab/Simulink software.The weighted root mean square(RMS)acceleration responses and the power spectral density(PSD)acceleration responses of the driver s seat heave,the pitch and roll angle of the cab in the low-frequency region are chosen as objective functions under different operation conditions of the vehicle.The results show that the impact of off-road terrains on the driver s ride comfort and health is clear under various conditions of deformable terrains and range of vehicle velocities.In particular,the driver s ride comfort is greatly affected by a soil terrain while the comfortable shake of the driver is strongly affected by a sand terrain.In addition,when the vehicle travels on a poor soil terrain in the frequency range below 4 Hz,more resonance peaks of acceleration PSD responses occurred than that on a rigid road of ISO 2631-1 level C.Thus,the driver s health is significantly affected by the deformable terrain in a low-frequency range.展开更多
Using the fuzzy rule-based classification method, normalized difference vegetation index (NDVI) images acquired from 1982 to 1998 were classified into seventeen phases. Based on these classification images, a probabil...Using the fuzzy rule-based classification method, normalized difference vegetation index (NDVI) images acquired from 1982 to 1998 were classified into seventeen phases. Based on these classification images, a probabilistic cellular automata-Markov Chain model was developed and used to simulate a land cover scenario of China for the year 2014. Spatiotemporal dynamics of land use/cover in China from 1982 to 2014 were then analyzed and evaluated. The results showed that the change trends of land cover type from 1998 to 2014 would be contrary to those from 1982 to 1998. In particular, forestland and grassland areas decreased by 1.56% and 1.46%, respectively, from 1982 to 1998, and should increase by 1.5% and 2.3% from 1998 to 2014, respectively.展开更多
基金The Science and Technology Support Program of Jiangsu Province(No.BE2014133)the Prospective Joint Research Program of Jiangsu Province(No.BY2014127-01)
文摘In order to evaluate the impact of off-road terrains on the ride comfort of construction vehicles,a nonlinear dynamic model of the construction vehicles interacting with the terrain deformations is established based on Matlab/Simulink software.The weighted root mean square(RMS)acceleration responses and the power spectral density(PSD)acceleration responses of the driver s seat heave,the pitch and roll angle of the cab in the low-frequency region are chosen as objective functions under different operation conditions of the vehicle.The results show that the impact of off-road terrains on the driver s ride comfort and health is clear under various conditions of deformable terrains and range of vehicle velocities.In particular,the driver s ride comfort is greatly affected by a soil terrain while the comfortable shake of the driver is strongly affected by a sand terrain.In addition,when the vehicle travels on a poor soil terrain in the frequency range below 4 Hz,more resonance peaks of acceleration PSD responses occurred than that on a rigid road of ISO 2631-1 level C.Thus,the driver s health is significantly affected by the deformable terrain in a low-frequency range.
基金Supported by the National Natural Science Foundation of China(No.30730021)the Applied Basic Research Programs of Yunnan Province,China(Nos.2011FZ140 and 2010CD047)
文摘Using the fuzzy rule-based classification method, normalized difference vegetation index (NDVI) images acquired from 1982 to 1998 were classified into seventeen phases. Based on these classification images, a probabilistic cellular automata-Markov Chain model was developed and used to simulate a land cover scenario of China for the year 2014. Spatiotemporal dynamics of land use/cover in China from 1982 to 2014 were then analyzed and evaluated. The results showed that the change trends of land cover type from 1998 to 2014 would be contrary to those from 1982 to 1998. In particular, forestland and grassland areas decreased by 1.56% and 1.46%, respectively, from 1982 to 1998, and should increase by 1.5% and 2.3% from 1998 to 2014, respectively.
