New approach to calculation of electromagnetic scattering by a perfectly conducting rectangular cylinder

1983 ◽  
Vol 19 (20) ◽  
pp. 861
Author(s):  
S. Sugimoto ◽  
S. Kozaki
Keyword(s):  
Electromagnetic Scattering ◽  
New Approach ◽  
Rectangular Cylinder

Research on Semi-Empirical Model for Backscattering Coefficient of Sea Clutter

2014 ◽  
Vol 654 ◽  
pp. 300-303
Author(s):  
Geng Kun Wu ◽  
Guang Rong Ji ◽  
Hong Xia Ren
Keyword(s):  
Target Detection ◽  
Empirical Model ◽  
Electromagnetic Scattering ◽  
Radar Target ◽  
Sea Clutter ◽  
Backscattering Coefficient ◽  
New Approach ◽  
Semi Empirical

To understand the influence of sea clutter on radar target detection, this paper simulates three typical backscattering coefficient models, i.e. GIT, TSC and HYB. Also, it proposes a new approach to evaluate the fitting degree between TSM and the three backscattering coefficient models. Finally, this paper gives the applicability of different models in the calculation of electromagnetic scattering.

Nonlinear Hydrostatic Restoring of Floating Platforms

2015 ◽  
Vol 10 (4) ◽  
Author(s):  
Mohammed Khair Al-Solihat ◽  
Meyer Nahon
Keyword(s):  
The Body ◽  
Circular Cylinders ◽  
Offshore Platforms ◽  
New Approach ◽  
Force Magnitude ◽  
Rectangular Cylinder ◽  
Inertial Frames ◽  
Action Center ◽  
Floating Platforms ◽  
Fully Coupled

This paper provides a comprehensive theoretical analysis to determine the nonlinear hydrostatic restoring loads and stiffnesses of a floating offshore platform. A new approach is developed to calculate the buoyancy forces and the corresponding moments for general 3D displacements of offshore platforms that utilize cylindrical floaters, such as barge (rectangular cylinder), spar, tension leg platform (TLP), and semisubmersible (circular cylinders) offshore platforms. The exact buoyancy force magnitude and point of action (center of buoyancy) and hydrostatic restoring moments for general fully coupled 3D displacements are derived. Exact expressions for the coupled water plane area restoring moments in pitch, roll, and yaw are derived in the body and inertial frames. The analysis is subsequently used to evaluate the hydrostatic loads and stiffness of floating cylinders that undergo large displacement, such as floating wind turbine (FWT) platforms. Moreover, it can be used to determine the equilibrium positions and orientation of free floating cylindrical bodies.

An Unpreconditioned Boundary-Integral for Iterative Solution of Scattering Problems with Non-Constant Leontovitch Impedance Boundary Conditions

2014 ◽  
Vol 15 (5) ◽  
pp. 1431-1460 ◽  
Author(s):  
D. Levadoux ◽  
F. Millot ◽  
S. Pernet
Keyword(s):  
Electromagnetic Scattering ◽  
Three Dimensional ◽  
Iterative Solution ◽  
Accurate Solution ◽  
Boundary Integral ◽  
Impedance Boundary Condition ◽  
Scattering Problems ◽  
Impedance Boundary ◽  
New Approach ◽  
Impedance Condition

AbstractThis paper concerns the electromagnetic scattering by arbitrary shaped three dimensional imperfectly conducting objects modeled with non-constant Leontovitch impedance boundary condition. It has two objectives. Firstly, the intrinsically well-conditioned integral equation (noted GCSIE) proposed in [30] is described focusing on its discretization. Secondly, we highlight the potential of this method by comparison with two other methods, the first being a two currents formulation in which the impedance condition is implicitly imposed and whose the convergence is quasi-optimal for Lipschitz polyhedron, the second being a CFIE-like formulation [14]. In particular, we prove that the new approach is less costly in term of CPU time and gives a more accurate solution than that obtained from the CFIE formulation. Finally, as expected, It is demonstrated that no preconditioner is needed for this formulation.

The O–C diagrams of minor planets − a new approach to modelling the rotation

1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss
Keyword(s):  
Error Analysis ◽  
Time Dependence ◽  
Theoretical Work ◽  
Minor Planet ◽  
Minor Planets ◽  
New Approach ◽  
Preliminary Results ◽  
Ccd Observations

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.

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