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Number of results: 6
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Abstract

This work addresses the problem of difficulties in classical interpretation of combination tones as non- linear distortions. One of the basic problems of such an interpretation is to point out the sources of these distortions. Besides, these kinds of distortions have numerous “anomalies” which are difficult to explain on the grounds of physics or physiology. The aim of the model presented in this paper is to show that combination tones phenomenon can be explained as an effect of central mechanisms. Most of existing theories of pitch perception focus mainly on virtual pitch perception and do not take into account combination tones as an element of the same mechanism. The proposed model of central auditory processing for pitch perception allows one to interpret in a coherent way both virtual pitches and combination tones phenomena. This model is of a demonstrative nature and gives an introduction to more advanced model. It belongs to the class of spectral models and it will be shown that such a model can be in a simple way extended to spectral - time model which is partially consistent with autocorrelation models.

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Authors and Affiliations

Tadeusz Ziębakowski
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Abstract

This paper presents mechanical fault detection in squirrel cage induction motors (SCIMs) by means of two recent techniques. More precisely, we have analyzed the rolling element bearing (REB) faults in SCIM. Rolling element bearing faults constitute a major problem among different faults which cause catastrophic damage to rotating machinery. Thus early detection of REB faults in SCIMs is of crucial importance. Vibration analysis is among the key concepts for mechanical vibrations of rotating electrical machines. Today, there is massive competition between researchers in the diagnosis field. They all have as their aim to replace the vibration analysis technique. Among them, stator current analysis has become one of the most important subjects in the fault detection field. Motor current signature analysis (MCSA) has become popular for detection and localization of numerous faults. It is generally based on fast Fourier transform (FFT) of the stator current signal. We have detailed the analysis by means of MCSA-FFT, which is based on the stator current spectrum. Another goal in this work is the use of the discrete wavelet transform (DWT) technique in order to detect REB faults. In addition, a new indicator based on the MCSA-DWT technique has been developed in this study. This new indicator has the advantage of expressing itself in the quantity and quality form. The acquisition data are presented and a comparative study is carried out between these recent techniques in order to ensure a final decision. The proposed subject is examined experimentally using a 3 kW squirrel cage induction motor test bed.

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Authors and Affiliations

N. Bessous
S. Sbaa
A.C. Megherbi
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Abstract

The continuous growth of smart communities and ever-increasing demand of sending or storing videos, have led to consumption of huge amount of data. The video compression techniques are solving this emerging challenge. However, H.264 standard can be considered most notable, and it has proven to meet problematic requirements. The authors present (BPMM) as a novel efficient Intra prediction scheme. We can say that the creation of our proposed technique was in a phased manner; it's emerged as a proposal and achieved impressive results in the performance parameters as compression ratios, bit rates, and PSNR. Then in the second stage, we solved the challenges of overcoming the obstacle of encoding bits overhead. In this research, we try to address the final phase of the (BPMM) codec and to introduce our approach in a global manner through realization of decoding mechanism. For evaluation of our scheme, we utilized VHDL as a platform. Final results have proven our success to pass bottleneck of this phase, since the decoded videos have the same PSNR that our encoder tells us, while preserving steady compression ratio treating the overhead. We aspire our BPMM algorithm will be adopted as reference design of H.264 in the ITU.

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Authors and Affiliations

Sara Hamdy
Abdelhalim Zekry
Wael A. Mohamed
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Abstract

A sample of late Viséan limestone from the Włodawa IG-4 borehole, east of Lublin, Poland, yielded a piece of a tooth and a few hundred well-preserved scales comparable to those of “Ctenacanthus” costellatus Traquair, 1884 from Glencartholm, Scotland, UK. Most of the scales are typical compound body scales of the ctenacanthid type. Their crowns are composed of several separate odontodes whose distal ends are turned backwards and bases are characterised by concave undersides. In the material, there are also sparse scales with similar crowns but with flat or convex bulbous bases, as well as ornamented plates and single, star-like denticles, probably from the head region. The taxonomic status of “Ctenacanthus” costellatus was analysed and a new generic name for that species, viz. Glencartius gen. nov., is proposed.

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Authors and Affiliations

Michał Ginter
Stanisław Skompski
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Abstract

Large floors of industrial enterprises, warehouses, stores, and shopping centres are quite heavily loaded with production technologies, transport mechanisms, stored material or shelf stackers. Regarding simple reinforcement and construction, industrial floors have been used in recent decades mainly reinforced with fibres from so-called fibre-reinforced concrete. Most slab failures are caused by extreme loads on the unbearable subsoil, a small amount of fibres, or by the shrinkage of concrete due to insufficient structural design of sliding, shrinking and expansion joints. Recently, however, in several constructions, structural failures have occurred caused by a volume-unstable subsoil in the form of a mixture of slag or metallurgical debris. The article deals with some failures of fibre concrete floors in practice, their methods of diagnostics and laboratory analysis of samples. The results are supplemented by practical examples of floor failures with respect to their origin.
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Authors and Affiliations

Radim Cajka
1
ORCID: ORCID
Jana Vaskova
1
ORCID: ORCID
Martina Smirakova
1
ORCID: ORCID
Kamil Burkovic
1
ORCID: ORCID
Zdenka Neuwirthova
1
ORCID: ORCID

  1. VSB Technical University of Ostrava, Faculty of Civil Engineering, Ludvíka Podéšte 1875/17708 00 Ostrava-Poruba, Czech Republic

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