Learning with belief levels

We study learning of predicate logics formulas from “elementary facts,” i.e. from the values of the predicates in the given model. Several models of learning are considered, but most of our attention is paid to learning with belief levels. We propose an axiom system which describes what we consider to be a human scientist's natural behavior when trying to explore these elementary facts. It is proved that no such system can be complete. However we believe that our axiom system is “practically” complete. Theorems presented in the paper in some sense confirm our hypothesis.     

Fusion of smartphone sensor data for classification of daily user activities

Multimedia Tools and Applications - New mobile applications need to estimate user activities by using sensor data provided by smart wearable devices and deliver context-aware solutions to users...     

Shakedown analysis of circular plates using a yield criterion of the mean

Structural optimization based on the shakedown theory is a powerful and promising technique. However, due to the nonlinearities of physical materials and the number of variable loads in real structures, it is computationally complex and time-consuming. To simplify the occurring non-linear, non-convex optimization problems, the paper suggests reducing the number of yield conditions. The so-called a yield criterion of the mean (integral yield condition) is analysed and explained in detail, which allows taking into account one yield condition for the entire finite element instead of multiple point-wise conditions. This approach shows promising results in numerical application to the optimization of a circular plate, considering a possibility of employing the yield criteria of the mean or pointwise yield conditions in different areas of the plate in particular. The methods applied are based on the assumptions of perfect plasticity and small deformations.     

E-beam lithography of computer generated holograms using a fully vectorial 3D beam propagation method

A fully vectorial 3D beam propagation method (BPM) has been applied to obtain a required pattern of computer generated hologram (CGH) with a variable profile of four phase levels. The computer reconstruction of the CGH image having one and two focal spots was performed by application of the fully vectorial 3D BPM method. After transferring the CGH by EBL technique an adequate phase profile was obtained. Inter-level parameter method was developed to obtain the estimated an electron beam dose required for the even topographical patterning. Using this method, an EBL exposure dose determined to achieve the required relief amplitude of 1.29 μm was 43 μC/cm². The manufactured holograms showed that the overall proposed production process, from the 3D BPM computer simulation to e-beam lithography, can be used to obtain good quality product with reasonable time and computational resources.     

Silver nanostructured catalyst for modification of dielectrics surface

The preparation of nano-size Ag particles and their application for forming nanostructured catalysts on various surfaces are described. Silver colloid solutions were prepared by reduction of Ag(I) salt by tin(II) and characterized by electron microscopy, X-ray diffraction and light absorption spectra. Depending on the colloid preparation conditions metal particles of 5-100 nm size were obtained. According to XRD data, the colloid particles contain Ag and SnO₂ phases and no metallic Sn. The Ag nanoparticles were found to be efficient electrocatalysts for anodic oxidation of formaldehyde in alkaline solutions. The catalytic activity of a glassy carbon electrode with Ag surface coverage of 0.3-1 μg cm⁻² is similar or even exceeds that of the metallic electrode. The silver particles were used for the initiation of the electroless copper deposition process on dielectrics; for that 1-2 μg cm⁻² Ag is needed.     

Catalytic Friedel–Crafts Acylation of Heteroaromatics

Catalytic Friedel–Crafts acylation of heteroaromatics has been achieved using metal triflates as catalysts. While conventional Friedel–Crafts acylation often requires the use of more than stoichiometric amounts of aluminum chloride, metal triflates such as tin(II) triflate, scandium triflate, and gallium triflate, etc. have enabled efficient acylation reactions by catalytic use.