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  • Author: Ján Kováč x
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Abstract

We describee some possible options for implementation of the Discrete multiwavelet transform (DMWT) of an image by using filter banks. DMWT can be implemented by two channel bank of vector filters which are made by cross-connected scalar filters. The properties of DGHM, CL, BiHermite and SA4 multiwavelets are here analyzed, and compression analysis for output normalization of DMWT is performed. A procedure is design of equivalent replacing of 2 channel multifilters bank by 4 channel bank of single scalar filters. Finally, we deal with a possible reduction and combinations of subbands and suggest their use.

Abstract

Compared to solid or laminated timber, the main point of the design of cross-laminated timber (CLT) is very low resistance and stiffness of the CLT cross layers. For the modeling and analyzing of the load distribution in CLT, various methods are available. The aim of this paper is to present the possible ways for load-bearing analysis of structural members subjected to uniaxial and biaxial bending in various software products and using various methods. A parametric analysis was performed with the aim to compare the results obtained by the analytical method, the model of the orthotropic slab, the grillage model and using the software based on the finite element method. The values of maximum deflection obtained by selected methods were compared. The mid-span deflection of beams subjected to uniaxial bending differs only slightly. In the case of slabs subjected to biaxial bending, more visible differences in results occurred. The simplified methods give the highest values on the safe side.

Abstract

The purpose of this paper is to develop convolution implementation of DGHM (Donovan, Geronimo, Harding, Massopust) multiwavelet image transform using a new approach of ordering wavelet coefficients at the second and higher levels. Firstly, the method of implementation of one-dimensional discrete multiwavelet transform (1D DMWT) for DGHM multiwavelet using discrete convolution and scalar filters is presented. Then, convolution implementation of DGHM multiwavelet image transform by application of 1D DMWT for two dimensions (2D) in a separable way is proposed. Next, the second level of 2D DMWT is performed in three possible ways. The novelty of the proposed implementation is in reordering of L subband wavelet coefficients at the first level into one subimage. The results are evaluated as the energy ratios between the transformed images in L subband at the second level and the input original image. According to the experimental results, the developed implementation of 2D DMWT is approximately 5% more effective in energy compression than the ones most commonly mentioned in the literature. This paper shows a possibility of convolution implementation of 2D DMWT with higher energy compression.

Abstract

The paper focuses on measuring and evaluating the impact of selected technical and technological factors -the height of adjustable guides and stretching force - on the side deflection of the saw band of a joinery band saw. There is a detailed description of the ways the side deflection can be measured. In order to find out the intensity of the stretching force was used portable tension meter SANDVIK 5000, enabling to check the tensile stress in the saw blades of a gang saw or in the saw bands of a band saw. The actual experiment was conducted on a joinery band saw, at the cutting rate vc = 15 m·s-1. The results of the measurements confirmed the theoretical assumption of the impact of the selected technical and technological factors on the stability of the saw band, where the side deflection decreases with increasing stretching force and increases with increasing height of the guides. The stability of the saw band affects the quality of the surface to be treated, thus saving the cost of machining the workpiece and making work productivity more efficient.

Abstract

The article deals with the research of operational reliability of forest felling machines with the method FMEA (Failure Mode and Effect Analysis) and its implementation for observed machines in the organization. Forwarders 810D by John Deere were chosen for this research. The research was realized in real operational conditions. Application of the FMEA method allows flexibility in case of unexpected situations and optimization of human potential abilities. FMEA tool is a tool preventing outages operational reliability and preventive tool for ensuring the maintenance of facilities. This paper explores and verifies the operational reliability theory in practical real-world conditions, resulting in a reduction in operating (variable) costs, minimization of failures and readiness and increased performance of observed machines.

Abstract

Three plots in Dry Polder Beša in Slovakia (E) and 3 plots in no flooded area (R) were chosen to assess the Cd, Pb and Ni contamination in the soil by using geo-accumulation index (Igeo) and anthropogenic contribution rate (ACR). Heavy metals content was measured at three depths (0‒0.2 m, 0.2‒0.4 m and 0.4‒0.6 m). It was found that the average content of Pb was 1.4 times higher and content of Ni 2.3 times higher at experimental area than at reference area. The average content of Cd were on the same level (E - 0.040 mg/kg, R - 0.041 mg/kg). The variability of heavy metals content in the soil was significantly influenced by soil depth and sampling plot and concentrations significantly correlated with soil organic carbon content (r - in the range of 0.41 to 0.65, p < 0.05). Geo-accumulation index indicates that the soils in the all of studied plots were polluted with respect to Ni, while were unpolluted with respect to Cd and Pb. Cd and Pb occurrence in these soils may be associated to the geochemical weathering. The value of the ACR indicate that anthropogenic input of Ni was 1.331 times higher in flooded area than in reference no flooded area. Different soil types can be arranged in descending Igeo values for Ni as follows: Luvisols ˃ Regosols ˃ Gleysols ˃ Chernozems. It was found that the content of Ni and Pb exceeded the critical values, in relation to transfer of contaminants from the soil to the plant , only at flooded area.

Neogene and Quaternary development of the Turiec Basin and landscape in its catchment: a tentative mass balance model

The development of the Turiec Basin and landscape evolution in its catchment has been reconstructed by methods of geological research (structural geology, sedimentology, paleoecology, and geochronological data) as well as by geophysics and geomorphology. The basin and its surrounding mountains were a subject of a mass balance study during periods of tectonic activity, accompanied by considerable altitudinal differentiation of relief and also during quiet periods, characterized by a development of planation surfaces in the mountains. The coarse clastic alluvial fans deposited beneath the offshore pelitic sediments document the rapid Middle Miocene uplift of mountains on the margin of the Turiec Basin. The Late Miocene finegrained sedimentation represents the main fill of this basin and its origin was associated with the formation of planation surfaces in the surrounding mountains. The rapid uplift of the western and northern parts of the catchment area during the latest Miocene and Early Pliocene times further generated the deposition of coarse-grained alluvial fans. The Late Pliocene basin inversion, due to uplift of the whole Western Carpathians mountain chain, was associated with the formation of the Early Quaternary pediment and ultimately with the formation of the Turiec river terrace systems.

Abstract

This article deals with creating a mathematical model, which is used for calculating the resulting maximum deformation of a rectangular metal sheet with the dimensions 1000 x 900 mm and a thickness of 0.67mm, using FEM. The manipulated object is fixed using vacuum grasping elements, which will be also considered in this calculation. To reach these results we use the programs ANSYS and MATLAB.