1,384 research outputs found

    Correlating matched-filter model for analysis and optimisation of neural networks

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    A new formalism is described for modelling neural networks by means of which a clear physical understanding of the network behaviour can be gained. In essence, the neural net is represented by an equivalent network of matched filters which is then analysed by standard correlation techniques. The procedure is demonstrated on the synchronous Little-Hopfield network. It is shown how the ability of this network to discriminate between stored binary, bipolar codes is optimised if the stored codes are chosen to be orthogonal. However, such a choice will not often be possible and so a new neural network architecture is proposed which enables the same discrimination to be obtained for arbitrary stored codes. The most efficient convergence of the synchronous Little-Hopfield net is obtained when the neurons are connected to themselves with a weight equal to the number of stored codes. The processing gain is presented for this case. The paper goes on to show how this modelling technique can be extended to analyse the behaviour of both hard and soft neural threshold responses and a novel time-dependent threshold response is described

    Variation of natural frequencies by circular saw blade rotation

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    In this paper the influence of circular saw blade rotation, slot shapes and number of slots on its natural frequencies and critical speeds is investigated. Firstly, the governing equation that describes the transverse vibrations of a stationary circular plate clamped at its centre is derived using Hamilton\u2019s principle and based on Kirchhoff-Love plate theory and von Karman strain theory. The results are then compared with the ones obtained using FEM method and the FEM method is then applied to the real circular saw blade model. Finally, influence of slot shapes and number of slots on natural frequencies and critical speeds is investigated

    Using a Total Quality Strategy in a new Practical Approach for Improving the Product Reliability in Automotive Industry

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    In this paper a Total Quality Management strategy is proposed, refined and used with the aim at improving the quality of large-mass industrial products far beyond the technical specifications demanded at the end-customer level. This approach combines standard and non-standard tools used for Reliability, Availability and Maintainability analysis. The procedure also realizes a stricter correlation between theoretical evaluation methods and experimental evidences as part of a modern integrated method for strengthening quality in design and process. A commercial Intake Manifold, largely spread in the market, is used as test-case for the validation of the methodology. As general additional result, the research underlines the impact of Total Quality Management and its tools on the development of innovation

    Entangled photon pairs produced by a quantum dot strongly coupled to a microcavity

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    We show theoretically that entangled photon pairs can be produced on demand through the biexciton decay of a quantum dot strongly coupled to the modes of a photonic crystal. The strong coupling allows to tune the energy of the mixed exciton-photon (polariton) eigenmodes, and to overcome the natural splitting existing between the exciton states coupled with different linear polarizations of light. Polariton states are moreover well protected against dephasing due to their lifetime ten to hundred times shorter than that of a bare exciton. Our analysis shows that the scheme proposed can be achievable with the present technology

    Strength Analysis of Eight-Wheel Bogie of Bucket Wheel Excavator

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    Crawler travel gear is a type of heavy vehicle propulsion that is commonly found in tanks, excavators, and specialized off-road vehicles. They have an advantage over wheels when it comes to robust vehicle weight distribution over soft terrain, and some disadvantages as well. They can damage paved roads and have complex design so, considering the enormous weight they must carry, their reliability must be determined and verified. The main parts of the assembly are the drive wheels, which move the crawler, and the supporting structure that holds four-wheel bogies and two-wheel bogies. In this paper, we present a methodology for FEM analysis of parts of an eight-wheel bogie according to DIN 22261-2 standard

    Conserved roles of Sam50 and metaxins in VDAC biogenesis

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    Voltage-dependent anion-selective channel (VDAC) is a β-barrel protein in the outer mitochondrial membrane that is necessary for metabolite exchange with the cytosol and is proposed to be involved in certain forms of apoptosis. We studied the biogenesis of VDAC in human mitochondria by depleting the components of the mitochondrial import machinery by using RNA interference. Here, we show the importance of the translocase of the outer mitochondrial membrane (TOM) complex in the import of the VDAC precursor. The deletion of Sam50, the central component of the sorting and assembly machinery (SAM), led to both a strong defect in the assembly of VDAC and a reduction in the steady-state level of VDAC. Metaxin 2-depleted mitochondria had reduced levels of metaxin 1 and were deficient in import and assembly of VDAC and Tom40, but not of three matrix-targeted precursors. We also observed a reduction in the levels of metaxin 1 and metaxin 2 in Sam50-depleted mitochondria, implying a connection between these three proteins, although Sam50 and metaxins seemed to be in different complexes. We conclude that the pathway of VDAC biogenesis in human mitochondria involves the TOM complex, Sam50 and metaxins, and that it is evolutionarily conserved

    Generalised Compositional Theories and Diagrammatic Reasoning

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    This chapter provides an introduction to the use of diagrammatic language, or perhaps more accurately, diagrammatic calculus, in quantum information and quantum foundations. We illustrate the use of diagrammatic calculus in one particular case, namely the study of complementarity and non-locality, two fundamental concepts of quantum theory whose relationship we explore in later part of this chapter. The diagrammatic calculus that we are concerned with here is not merely an illustrative tool, but it has both (i) a conceptual physical backbone, which allows it to act as a foundation for diverse physical theories, and (ii) a genuine mathematical underpinning, permitting one to relate it to standard mathematical structures.Comment: To appear as a Springer book chapter chapter, edited by G. Chirabella, R. Spekken

    Effectiveness of Different Analytical Methods for the Characterization of Propolis : a Case of Study in Northern Italy

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    Propolis is used as folk medicine due to its spectrum of alleged biological and pharmaceutical properties and it is a complex matrix not still totally characterized. Two batches of propolis coming from two different environments (plains of Po Valley and the hilly Ligurian\u2013 Piedmont Apennines) of Northern Italy were characterized using different analytical methods: Spectrophotometric analysis of phenols, flavones and flavonols, and DPPH radical scavenging activity, HPLC, NMR, HSPME and GC\u2013MS and HPLC\u2013MS Orbitrap. Balsam and moisture content were also considered. No statistical differences were found at the spectrophotometric analysis; balsam content did not vary significantly. The most interesting findings were in the VOCs composition, with the Po Valley samples containing compounds of the resins from leaf buds of Populus nigra L. The hills (Appennines) samples were indeed characterize by the presence of phenolic glycerides already found in mountain environments. HPLC\u2013Q-Exactive-Orbitrap\uae\u2013MS analysis is crucial in appropriate recognition of evaluate number of metabolites, but also NMR itself could give more detailed information especially when isomeric compounds should be identified. It is necessary a standardized evaluation to protect and valorize this production and more research on propolis characterization using different analytical techniques

    Residual stress evaluation in friction stir welding of aluminum plates by means of acoustic emission and ultrasonic waves

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    © Faculty of Mechanical Engineering, Belgrade. The residual stress assessment in structures is essential for optimization of the structures' design. The attention of this paper is focused on how acoustic emission signals caused by tensile loading of the friction stir welded aluminum plates are expected to vary depending upon the residual stress. To this aim, the distribution of residual stresses in two friction stir welded aluminum specimens was firstly evaluated by ultrasonic stress measurement. AE signals were then produced during tensile tests and captured using AE sensors. The obtained AE signals were analyzed using statistical features including crest factor, cumulative crest factor and sentry function. It was found that the crest factor could be used to identify the presence of the residual stresses and that the trends of sentry function are in good agreement with the results of crest factor and cumulative crest factor
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