In this study, the bidirectional reflectance distribution function （BRDF） of a one-dimensional conducting rough surface and a dielectric rough surface are calculated with different frequencies and roughness values i...In this study, the bidirectional reflectance distribution function （BRDF） of a one-dimensional conducting rough surface and a dielectric rough surface are calculated with different frequencies and roughness values in the microwave band by using the method of moments, and the relationship between the bistatic scattering coefficient and the BRDF of a rough surface is expressed. From the theory of the parameters of the rough surface BRDF, the parameters of the BRDF are obtained using a genetic algorithm. The BRDF of a rough surface is calculated using the obtained parameter values. Further, the fitting values and theoretical calculations of the BRDF are compared, and the optimization results are in agreement with the theoretical calculation results. Finally, a reference for BRDF modeling of a Gaussian rough surface in the microwave band is provided by the proposed method.展开更多
By using function S-rough sets（function singular rough sets）, this paper gives rough law generation and the theorem of rough law generation.Based on these results above, the paper proposes rough law separation, the ...By using function S-rough sets（function singular rough sets）, this paper gives rough law generation and the theorem of rough law generation.Based on these results above, the paper proposes rough law separation, the theorem of rough law separation, the compound generation theorem of rough law bands, and the principle of rough law bands.In the end, an application of rough law separation in recognizing the risk law of profit is presented.展开更多
A normalized two-dimensional band-limited Weierstrass fractal function is used for modelling the dielectric rough surface. An analytic solution of the scattered field is derived based on the Kirchhoff approximation. T...A normalized two-dimensional band-limited Weierstrass fractal function is used for modelling the dielectric rough surface. An analytic solution of the scattered field is derived based on the Kirchhoff approximation. The variance of scattering intensity is presented to study the fractal characteristics through theoretical analysis and numerical calculations. The important conclusion is obtained that the diffracted envelope slopes of scattering pattern can be approximated as a slope of linear equation. This conclusion will be applicable for solving the inverse problem of reconstructing rough surface and remote sensing.展开更多
运用基于矩量法(method of moment,MoM)结合基尔霍夫近似(Kirchhoff approximation,KA)的混合算法研究一维带限Weierstrass分形分层介质粗糙面的电磁波透射问题.在混合算法中将上层粗糙面和下层粗糙面分别划分到MoM区域和KA区域,数值计...运用基于矩量法(method of moment,MoM)结合基尔霍夫近似(Kirchhoff approximation,KA)的混合算法研究一维带限Weierstrass分形分层介质粗糙面的电磁波透射问题.在混合算法中将上层粗糙面和下层粗糙面分别划分到MoM区域和KA区域,数值计算得到透射系数随透射波的散射角的变化,讨论粗糙面分维数、高度起伏均方根、底层介质介电常数、中间层介质介电常数和厚度、入射波频率对透射系数的影响,结果表明上层粗糙面参数对透射系数有显著影响,而下层粗糙面参数对透射系数影响较小.展开更多
基金Project supported by the National Natural Science Foundation for Distinguished Young Scholars of China （Grant No. 61225002）, the Aeronautical Science Fund and Aviation Key Laboratory of Science and Technology on Avionics Integrated Sensor System Simulation, China （Grant No. 20132081015）, and the Fundamental Research Funds for the Central Universities, China （Grant No. SPSZ031403）
文摘In this study, the bidirectional reflectance distribution function （BRDF） of a one-dimensional conducting rough surface and a dielectric rough surface are calculated with different frequencies and roughness values in the microwave band by using the method of moments, and the relationship between the bistatic scattering coefficient and the BRDF of a rough surface is expressed. From the theory of the parameters of the rough surface BRDF, the parameters of the BRDF are obtained using a genetic algorithm. The BRDF of a rough surface is calculated using the obtained parameter values. Further, the fitting values and theoretical calculations of the BRDF are compared, and the optimization results are in agreement with the theoretical calculation results. Finally, a reference for BRDF modeling of a Gaussian rough surface in the microwave band is provided by the proposed method.
基金supported partly by the Natural Science Foundation of Shandong Province of China (Y2007Ho2)the Elementary and Advanced Technology Foundation of Henan Province of China (082300410040)
文摘By using function S-rough sets（function singular rough sets）, this paper gives rough law generation and the theorem of rough law generation.Based on these results above, the paper proposes rough law separation, the theorem of rough law separation, the compound generation theorem of rough law bands, and the principle of rough law bands.In the end, an application of rough law separation in recognizing the risk law of profit is presented.
基金supported by the National Natural Science Foundation of China (Grant No 60571058)Specialized Research Fund for the Doctoral Program of Higher Education, China (Grant No 20070701010)
文摘A normalized two-dimensional band-limited Weierstrass fractal function is used for modelling the dielectric rough surface. An analytic solution of the scattered field is derived based on the Kirchhoff approximation. The variance of scattering intensity is presented to study the fractal characteristics through theoretical analysis and numerical calculations. The important conclusion is obtained that the diffracted envelope slopes of scattering pattern can be approximated as a slope of linear equation. This conclusion will be applicable for solving the inverse problem of reconstructing rough surface and remote sensing.
文摘运用基于矩量法(method of moment,MoM)结合基尔霍夫近似(Kirchhoff approximation,KA)的混合算法研究一维带限Weierstrass分形分层介质粗糙面的电磁波透射问题.在混合算法中将上层粗糙面和下层粗糙面分别划分到MoM区域和KA区域,数值计算得到透射系数随透射波的散射角的变化,讨论粗糙面分维数、高度起伏均方根、底层介质介电常数、中间层介质介电常数和厚度、入射波频率对透射系数的影响,结果表明上层粗糙面参数对透射系数有显著影响,而下层粗糙面参数对透射系数影响较小.
