351 research outputs found

    Notch Filtering Suitable for Real Time Removal of Power Line Interference

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    This paper presents a high performance notch filtering for real time suppression of power line interference in a general signal. The disturbing signal is suppressed using an optimal notch FIR filter with tunable notch frequency. The tuning of the filter preserves its selectivity, most importantly the specified attenuation at the notch frequency. One example and two Matlab functions demonstrate the performance, robustness and usefulness of the proposed procedure for the design and tuning of optimal notch FIR filters suitable in the real time notch filtering

    On qq- Component Models on Cayley Tree: The General Case

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    In the paper we generalize results of paper [12] for a qq- component models on a Cayley tree of order k≄2k\geq 2. We generalize them in two directions: (1) from k=2k=2 to any k≄2;k\geq 2; (2) from concrete examples (Potts and SOS models) of q−q- component models to any qq- component models (with nearest neighbor interactions). We give a set of periodic ground states for the model. Using the contour argument which was developed in [12] we show existence of qq different Gibbs measures for qq-component models on Cayley tree of order k≄2k\geq 2.Comment: 8 page

    Modelling design of multiphase bubble-bed reactors for advanced food-industry applications

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    An EC project (IC15-CT98-0904 / PL979021) under this title commenced November 1998 courtesy of Dr Jindrich Zahradnik, sadly since deceased. In dedication to his memory overviewed here are contributions from the four partners whose lead investigators appear as authors (plus coordinator as corresponding author) with principals and researchers recognised in cited literature. A website (www.copernicus.aston.ac.uk) has been launched to disseminate major individual components and collaborations facilitated by study exchanges, also envisaged exploitation by industries. Drawing on this material we outline partners' established expertise and its unification under EC umbrella funding. To avoid confusion on due credit for contributions, references are designated by first letters of the above-named authors. At risk of appearing to favour ones' own wares, we humbly refer readers to our cited papers for contextual commentaries

    A Contour Method on Cayley tree

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    We consider a finite range lattice models on Cayley tree with two basic properties: the existence of only a finite number of ground states and with Peierls type condition. We define notion of a contour for the model on the Cayley tree. By a contour argument we show the existence of ss different (where ss is the number of ground states) Gibbs measures.Comment: 12 page

    Free Energy Minimizers for a Two--Species Model with Segregation and Liquid-Vapor Transition

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    We study the coexistence of phases in a two--species model whose free energy is given by the scaling limit of a system with long range interactions (Kac potentials) which are attractive between particles of the same species and repulsive between different species.Comment: 32 pages, 1 fig, plain tex, typeset twic

    Ordering and Demixing Transitions in Multicomponent Widom-Rowlinson Models

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    We use Monte Carlo techniques and analytical methods to study the phase diagram of multicomponent Widom-Rowlinson models on a square lattice: there are M species all with the same fugacity z and a nearest neighbor hard core exclusion between unlike particles. Simulations show that for M between two and six there is a direct transition from the gas phase at z < z_d (M) to a demixed phase consisting mostly of one species at z > z_d (M) while for M \geq 7 there is an intermediate ``crystal phase'' for z lying between z_c(M) and z_d(M). In this phase, which is driven by entropy, particles, independent of species, preferentially occupy one of the sublattices, i.e. spatial symmetry but not particle symmetry is broken. The transition at z_d(M) appears to be first order for M \geq 5 putting it in the Potts model universality class. For large M the transition between the crystalline and demixed phase at z_d(M) can be proven to be first order with z_d(M) \sim M-2 + 1/M + ..., while z_c(M) is argued to behave as \mu_{cr}/M, with \mu_{cr} the value of the fugacity at which the one component hard square lattice gas has a transition, and to be always of the Ising type. Explicit calculations for the Bethe lattice with the coordination number q=4 give results similar to those for the square lattice except that the transition at z_d(M) becomes first order at M>2. This happens for all q, consistent with the model being in the Potts universality class.Comment: 26 pages, 15 postscript figure

    Combining stable isotope analysis and conventional techniques to improve knowledge of the diet of the European Roller Coracias garrulus

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    Diet studies are crucial for understanding the ecology and evolution of species, as well as for establishing appropriate conservation and management strategies. However, they remain methodologically challenging due to variation between seasons, sites, sexes or age groups and even variation between individuals. Due to method-specific characteristics and biases, a combination of existing techniques can overcome the inherent limitations of each technique and provide a more accurate and broad picture of species’ food preferences. Here, we examine diet information obtained using three different assessment methods to better understand the trophic ecology of the European Roller Coracias garrulus, a species targeted by conservation measures in Europe. First, we analysed regurgitated pellets and video recordings to report the diet composition of adult and nestling Rollers, respectively. Secondly, we used stable isotope analysis (SIA) to investigate adult sexual diet segregation as well as to confirm the main findings regarding adult and nestling diets obtained through conventional methods. Based on the analysis of pellets, the diet of adult Rollers was dominated by Coleoptera, while camera images revealed that the diet of nestlings was dominated by Orthoptera, mainly grasshoppers and bush crickets. Blood isotopic signatures of adult and nestling Rollers confirmed the results obtained through pellet and video recording techniques. Of the 45 three methods, pellet analysis contained the most comprehensive trophic information regarding the detectable prey spectrum and prey species contribution, and also provided basic diet information to inform the SIA. Our results also highlight the potential of SIA for assessing intra-specific variation in diet by sampling individuals of known age and sex, which is often unfeasible through conventional approaches. SIA analysis showed no differences in ή13C and ή15N ratios of blood between males and females and a high degree of overlap amongst isotopic niches, suggesting no sex-specific partitioning in resource use. Overall, we showed that the combination of different methods could be used to gain new and clearer insights into avian trophic ecology that are essential for informing habitat management aiming to improve availability of foraging resources
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