Noise level in a marine environment has raised extensive concern in the scientific community.The research is carried out on i4 Ocean platform following the process of ocean noise model integrating,noise data extractin...Noise level in a marine environment has raised extensive concern in the scientific community.The research is carried out on i4 Ocean platform following the process of ocean noise model integrating,noise data extracting,processing,visualizing,and interpreting,ocean noise map constructing and publishing.For the convenience of numerical computation,based on the characteristics of ocean noise field,a hybrid model related to spatial locations is suggested in the propagation model.The normal mode method K/I model is used for far field and ray method CANARY model is used for near field.Visualizing marine ambient noise data is critical to understanding and predicting marine noise for relevant decision making.Marine noise map can be constructed on virtual ocean scene.The systematic marine noise visualization framework includes preprocessing,coordinate transformation interpolation,and rendering.The simulation of ocean noise depends on realistic surface.Then the dynamic water simulation gird was improved with GPU fusion to achieve seamless combination with the visualization result of ocean noise.At the same time,the profile and spherical visualization include space,and time dimensionality were also provided for the vertical field characteristics of ocean ambient noise.Finally,marine noise map can be published with grid pre-processing and multistage cache technology to better serve the public.展开更多
Several representative studies on China＇s carbon emission scenarios in 2050 are compared in scenario settings, methodologies, macro parameters, energy consumption and structure, carbon emissions, and carbon emission ...Several representative studies on China＇s carbon emission scenarios in 2050 are compared in scenario settings, methodologies, macro parameters, energy consumption and structure, carbon emissions, and carbon emission intensity. Under the baseline scenario of the present policy framework, the future energy structure will be optimized and carbon emission intensity will decrease continually. China＇s carbon emissions up to 2050 show a significant increase reaching between 11.9 Gt and 16.2 Gt CO2 in 2050. By strengthening a low carbon policy, the optimization of energy structure and the decline in carbon emission intensity will become more obvious within the comparative scenarios, which show a significant decrease in carbon emission until 2050 reaching only between 4.3 Gt and 9.5 Gt CO2 bv then.展开更多
A new algorithm for linear instantaneous independent component analysis is proposed based on maximizing the log-likelihood contrast function which can be changed into a gradient equation.An iterative method is introdu...A new algorithm for linear instantaneous independent component analysis is proposed based on maximizing the log-likelihood contrast function which can be changed into a gradient equation.An iterative method is introduced to solve this equation efficiently.The unknown probability density functions as well as their first and second derivatives in the gradient equation are estimated by kernel density method.Computer simulations on artificially generated signals and gray scale natural scene images confirm the efficiency and accuracy of the proposed algorithm.展开更多
基金supported by the Global Change and Air-Sea Interaction Project (GASI-03-01-01-09)the National Natural Science Foundation of China under Grant No.61170106+1 种基金the Project funded by China Postdoctoral Science Foundation under Grant No.2015M571993Qingdao Postdoctoral Application Research Funded Project
文摘Noise level in a marine environment has raised extensive concern in the scientific community.The research is carried out on i4 Ocean platform following the process of ocean noise model integrating,noise data extracting,processing,visualizing,and interpreting,ocean noise map constructing and publishing.For the convenience of numerical computation,based on the characteristics of ocean noise field,a hybrid model related to spatial locations is suggested in the propagation model.The normal mode method K/I model is used for far field and ray method CANARY model is used for near field.Visualizing marine ambient noise data is critical to understanding and predicting marine noise for relevant decision making.Marine noise map can be constructed on virtual ocean scene.The systematic marine noise visualization framework includes preprocessing,coordinate transformation interpolation,and rendering.The simulation of ocean noise depends on realistic surface.Then the dynamic water simulation gird was improved with GPU fusion to achieve seamless combination with the visualization result of ocean noise.At the same time,the profile and spherical visualization include space,and time dimensionality were also provided for the vertical field characteristics of ocean ambient noise.Finally,marine noise map can be published with grid pre-processing and multistage cache technology to better serve the public.
基金supported by the "Low Carbon Economy Academy Special Programs,Tsinghua University Independent Research Plan"
文摘Several representative studies on China＇s carbon emission scenarios in 2050 are compared in scenario settings, methodologies, macro parameters, energy consumption and structure, carbon emissions, and carbon emission intensity. Under the baseline scenario of the present policy framework, the future energy structure will be optimized and carbon emission intensity will decrease continually. China＇s carbon emissions up to 2050 show a significant increase reaching between 11.9 Gt and 16.2 Gt CO2 in 2050. By strengthening a low carbon policy, the optimization of energy structure and the decline in carbon emission intensity will become more obvious within the comparative scenarios, which show a significant decrease in carbon emission until 2050 reaching only between 4.3 Gt and 9.5 Gt CO2 bv then.
文摘A new algorithm for linear instantaneous independent component analysis is proposed based on maximizing the log-likelihood contrast function which can be changed into a gradient equation.An iterative method is introduced to solve this equation efficiently.The unknown probability density functions as well as their first and second derivatives in the gradient equation are estimated by kernel density method.Computer simulations on artificially generated signals and gray scale natural scene images confirm the efficiency and accuracy of the proposed algorithm.
