Thermomechanical couplings in shape memory alloy materials

In this work we address several theoretical and computational issues which are related to the thermomechanical modeling of shape memory alloy materials. More specifically, in this paper we revisit a non-isothermal version of the theory of large deformation generalized plasticity which is suitable for describing the multiple and complex mechanisms occurring in these materials during phase transformations. We also discuss the computational implementation of a generalized plasticity based constitutive model and we demonstrate the ability of the theory in simulating the basic patterns of the experimentally observed behavior by a set of representative numerical examples

FQUERY III+: A “human-consistent” database querying system based on fuzzy logic with linguistic quantifiers

Using a fuzzy-logic-based calculus of linguistically quantified propositions we present FQUERY III+, a new, more “human-friendly” and easier-to-use implementation of a querying scheme proposed originally by Kacprzyk and Ziołkowski to handle imprecise queries including a linguistic quantifier as, e.g. find all records in which most (almost all, much more than 75%, … or any other linguistic quantifier) of the important attributes (out of a specified set) are as desired (e.g. equal to five, more than 10, large, more or less equal to 15, etc.). FQUERY III+ is an “add-on” to Ashton-Tate's dBase III Plus

The Radar Ambiguity Function Application for the Frequency Modulated Signals Designing

The optimization of the transmitted signal time-frequency structure is the very important part of the radar system design from the point of view of the radar system effectiveness. In this meaning the radar ambiguity function is the basic tool used for the radar system features testing. The synthesis procedure of the signal with simultaneous amplitude and phase manipulation is presented in the paper. The procedure is based on the Zak transform that is connected with the radar ambiguity function. The Legendre polynomials were applied in the procedure mentioned above. The results of the simulation tests are presented as examples of the consideration main effects

Cholesky decomposition techniques in electronic structure theory

We review recently developed methods to efficiently utilize the Cholesky decomposition technique in electronic structure calculations. The review starts with a brief introduction to the basics of the Cholesky decomposition technique. Subsequently, examples of applications of the technique to ab inito procedures are presented. The technique is demonstrated to be a special type of a resolution-of-identity or density-fitting scheme. This is followed by explicit examples of the Cholesky techniques used in orbital localization, computation of the exchange contributionto the Fock matrix, in MP2, gradient calculations, and so-called method specific Cholesky decomposition. Subsequently, examples of calibration of the method with respect to computed total energies, excitation energies, and auxiliary basis set pruning are presented. In particular, it is demonstrated that the Cholesky method is an unbiased method to derive auxiliary basis sets. Furthermore, details of the implementational considerations are put forward and examples from a parallel Cholesky decomposition scheme is presented. Finally, an outlook and perspectives are presented, followed by a summary and conclusions section. We are of the opinion that the Cholesky decomposition method is a technique that has been overlooked for too long. We have just recently started to understand how to efficiently incorporate the method in existing ab initio programs. The full potential of the Cholesky technique has not yet been fully explored