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A three-dimensional "full-polarized" model for arbitrary transmitter, receiver and target motions in bistatic synthetic aperture radar configurations is proposed. Qualitative validation of this model is presented through comparison with existing results and quantitative validation is obtained from proposed general analytical resolution equations. To take into account complex targets, geometric theory of diffraction based models are considered. Some numerical results are proposed in bistatic and monostatic configurations which permit to check the performance of the proposed model and to highlight the interest of the bistatic synthetic aperture radar imaging. [ABSTRACT FROM AUTHOR]

Database systems that can efficiently manage complex objects are increasingly needed in many different fields, Such as office automation, knowledge processing, CAD/CAM, CASE, etc. A hit of recent complex object database systems support the concepts of object identity and object identifier. Following an object identifier to access the referenced object is called navigation operation and is an essential operation in dealing with complex objects. Navigation operation is a difficult operation to implement efficiently since every navigation operation inherently causes one disk access operation. This paper proposes a scheme to notably. accelerate the navigation operation among a sea of complex objects, by increasing the effective number of objects in one disk page. The main concept of the presented technique is threefold. The first idea is to store a cached value within a complex object that is referencing another complex object. The second is that when the referenced object, is to be updated the update propagation is delayed until the time when the cached value is referenced. The third is to utilize a hashed table on main memory to efficiently validate the consistency between the cached values and the original values. [ABSTRACT FROM AUTHOR]

Context-free grammars provide the basis for many useful tools such as parser-generators, compiler-compilers and syntax-directed editors. This paper demonstrates the potential benefits obtained when context-free grammars are used to define complex objects in the relational model. The grammar formalism facilitates relational queries on the hierarchical structure of these objects and promotes the use of grammar-based tools as front ends to relational database systems. [ABSTRACT FROM AUTHOR]

POFACETS is an implementation of the Physical Optics approximation for predicting the radar cross section (RCS) of complex objects [1]. It utilizes the scientific computational features of MATLAB and its graphical-user-interface (GUI) functions to provide an error-free encoding of input parameters and efficient calculation of RCS. POFACETS provides a convenient tool for a “first cut” at the RCS of complex shapes by representing its constituent parts by triangular facets. The software calculates the monostatic or bistatic RCS of the object for the parameters specified by the user, and displays plots for the model's geometry and its RCS. The latest version (POFACETS 3.0) features new options and tools for complex target design, and provides new computational capabilities, including the approximate effects of the ground, the exploitation of symmetry planes in targets, and the effects of materials and coatings [2]. The software is ideal for use by students on projects and for instruction. It has been used in the past by students in the Naval Postgraduate School's Aeronautical Engineering Department and Total Ship Systems Engineering Program to compute the RCS of their platform entries for student design competitions. [ABSTRACT FROM AUTHOR]