Brno University of Technology

About: Brno University of Technology is a education organization based out in Brno, Czechia. It is known for research contribution in the topics: Fracture mechanics & Filter (video). The organization has 6339 authors who have published 15226 publications receiving 194088 citations. The organization is also known as: Vysoké učení technické v Brně & BUT.

Evolutionary design of gate-level polymorphic digital circuits

Abstract: A method for the evolutionary design of polymorphic digital combinational circuits is proposed. These circuits are able to perform different functions (e.g. to switch between the adder and multiplier) only as a consequence of the change of a sensitive variable, which can be a power supply voltage, temperature etc. However, multiplexing of standard solutions is not utilized. The evolved circuits exhibit a unique structure composed of multifunctional polymorphic gates considered as building blocks instead. In many cases the area-efficient solutions were discovered for typical tasks of the digital design. We demonstrated that it is useful to combine polymorphic gates and conventional gates in order to obtain the required functionality.

Influence of superimposed biaxial stress on the tensile strength of perfect crystals from first principles

Abstract: Influence of biaxial stresses applied perpendicularly to the [100] loading axis on the theoretical tensile strength is studied from first principles. Ten crystals of cubic metals and three crystals of diamond ceramics were selected as particular case studies. Obtained results show that, within a limited range of biaxial stresses, the tensile strength monotonously increases with increasing biaxial tensile stress for most of the studied metals. Within the range, the dependence can be approximated by a linear function. Beyond the range, the dependence shows a maximum that usually appears in the tensile range of biaxial stresses. On the other hand, some of the materials (Si, Ni, Cu, and Ge) exhibit a maximum tensile strength at nearly uniaxial stress state, and the superposition of both tensile and compressive biaxial stresses reduces the tensile strength. Unlike the other crystals, diamond revealed a maximum under compressive biaxial stress.

Relaxation processes in PVAc-HA nanocomposites

Abstract: Fundamental principles of polymer physics were used for description of relaxation behavior of polymer chain near solid surface. In a nanocomposite, consid- erable portion of polymer matrix is in contact with the filler surface even at very low filler loadings. In this study, nanocomposite was considered as a two component sys- tem consisting of (i) bulk polymer matrix and (ii) effective particles composed of adsorbed polymer shell and filler particle core. Both polymer phases, i.e., bulk and immobilized, are able to relax, however, each of them on a different time scale. Thus, above the neat matrix Tg, these two phases undergo (i) free and (ii) retarded repta- tion dynamics due to the adsorption processes on the filler surface, respectively. Relaxation time was calculated for each phase using the reptation theory. To calcu- late the mixed response of the whole polymer nanocomposite, a simple rule of mix- tures model and percolation model were used. Calculated composite relaxation times were correlated with experimental modulus recovery data measured after the Payne effect in poly(vinylacetate)-hydroxyapatite nanocomposite. Good agreement was found between theoretical predictions and experimental data. V C 2007 Wiley Periodicals, Inc.

Rapid vanishing point estimation for general road detection

Abstract: This paper deals with fast vanishing point estimation for autonomous robot navigation. Preceding approaches showed suitable results and vanishing point estimation was used in many robotics tasks, especially in the detection of illstructured roads. The main drawback of such approaches is the computational complexity - the possibilities of hardware accelerations are mentioned in many papers, however, we believe, that the biggest benefit of a vanishing point estimation algorithm is for primarily tele-operated robots in the case of signal loss, etc., that cannot use specialized hardware just for this feature. In this paper, we investigate possibilities of an efficient implementation by the expansion of Gabor wavelets into a linear combination of Haar-like box functions to perform fast filtering via integral image trick and discuss the utilization of superpixels in the voting scheme to provide a significant speed-up (more than 40 times), while we loose only 3–5% in precision.

Physical Demonstration of Polymorphic Self-Checking Circuits

Abstract: Polymorphic gates can be considered as a new reconfigurable technology capable of integrating logic functions with sensing in a single compact structure. Polymorphic gates whose logic function can be controlled by the level of the power supply voltage (Vdd) represent a special class of polymorphic gates. A new polymorphic NAND/NOR gate controlled by Vdd is presented. This gate was fabricated and utilized in a self-checking polymorphic adder. This paper presents an experimental evaluation of this novel implementation.