Using Mizar [9], and the formal topological space structure (FMT_Space_Str) [19], we introduce the three U-FMT conditions (U-FMT filter, U-FMT with point and U-FMT local) similar to those VI, VII, VIII and VIV of the proposition 2 in [10]: If to each element x of a set X there corresponds a set B(x) of subsets of X such that the properties VI, VII, VIII and VIV are satisfied, then there is a unique topological structure on X such that, for each x ∈ X, B(x) is the set of neighborhoods of x in this topology. We present a correspondence between a topological space and a space defined with the formal topological space structure with the three U-FMT conditions called the topology from neighbourhoods. For the formalization, we were inspired by the works of Bourbaki [11] and Claude Wagschal [31].
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We analyze several "strong meager" properties for filters on the natural numbers between the classical Baire property and a filter being $F_σ$. Two such properties have been studied by Talagrand and a few more combinatorial ones are investigated. In particular, we define the notion of a P⁺-filter, a generalization of the traditional concept of P-filter, and prove the existence of a non-meager P⁺-filter. Our motivation lies in understanding the structure of filters generated by complements of members of a maximal almost disjoint family.
Hilbert algebras are important tools for certain investigations in intuitionistic logic and other non-classical logic and as a generalization of Hilbert algebra a new algebraic structure, called a GE-algebra (generalized exchange algebra), is introduced and studied its properties. We consider filters, upper sets and congruence kernels in a GE-algebra. We also characterize congruence kernels of transitive GE-algebras.
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The class of bipartite pseudo-BL algebras (denoted by BP) and the class of strongly bipartite pseudo-BL algebras (denoted by BP0) are investigated. We prove that the class BP0 is a variety and show that BP is closed under subalgebras and arbitrary direct products but it is not a variety. We also study connections between bipartite pseudo-BL algebras and other classes of pseudo-BL algebras.
Pseudo BL-algebras are a noncommutative extention of BL-algebras. In this paper we study good pseudo BL-algebras and consider some classes of these algebras.
Some properties of filters on a lattice L are studied with respect to a congruence on L. The notion of a θ-filter of L is introduced and these filters are then characterized in terms of classes of θ. For distributive L, an isomorphism between the lattice of θ-filters of L and the lattice of filters of $L_{/θ}$ is obtained.
We prove a characterization theorem for filters, proper filters and ultrafilters which is a kind of converse of Łoś's theorem. It is more natural than the usual intuition of these terms as large sets of coordinates, which is actually unconvincing in the case of ultrafilters. As a bonus, we get a very simple proof of Łoś's theorem.
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First, we define in Mizar [5], the Cartesian product of two filters bases and the Cartesian product of two filters. After comparing the product of two Fréchet filters on ℕ (F1) with the Fréchet filter on ℕ × ℕ (F2), we compare limF₁ and limF₂ for all double sequences in a non empty topological space. Endou, Okazaki and Shidama formalized in [14] the “convergence in Pringsheim’s sense” for double sequence of real numbers. We show some basic correspondences between the p-convergence and the filter convergence in a topological space. Then we formalize that the double sequence [...] converges in “Pringsheim’s sense” but not in Frechet filter on ℕ × ℕ sense. In the next section, we generalize some definitions: “is convergent in the first coordinate”, “is convergent in the second coordinate”, “the lim in the first coordinate of”, “the lim in the second coordinate of” according to [14], in Hausdorff space. Finally, we generalize two theorems: (3) and (4) from [14] in the case of double sequences and we formalize the “iterated limit” theorem (“Double limit” [7], p. 81, par. 8.5 “Double limite” [6] (TG I,57)), all in regular space. We were inspired by the exercises (2.11.4), (2.17.5) [17] and the corrections B.10 [18].
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Biomedical signals are usually low amplitude and high bandwidth signals. EEG signals are very low amplitude (generally less than 300 μV) and very high bandwidth (range from 0.5 to 100 Hz), too. EEG was used to assist in the diagnosis of brain damage, Alzheimer disease and Parkinson disease, and certain mental disorders. In this study amplifier and filters designed with CCII+ and these simulations are performed with PSPICE program. Normal brain signal, the Alzheimer brain signal, epilepsy brain signal are compared, the shrinking hippocampus compared 25 years old normal brain, 75 years old normal brain and 75 years old with the Alzheimer brain.
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The concepts of I-convergence and I-Cauchy condition are a generalization of statistical convergence and statistical Cauchy conditions and are dependent on the notion of the ideal I of subsets of the set N of positive integers. In this paper, we shall introduce two new notions of I-uniform continuity and I-uniform boundedness of a function with values in R or in a metric space and then study their basic properties.
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We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres) and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections).
Envelope constrained filter design is concerned with the time domain synthesis of a filter whose response to a specified input signal stays within prescribed upper and lowe bounds and in addition has minimal noise enhancement. In many practical applications, a "soft" approach, such as least mean square, is not the most suitable and it becomes necessary to use "hard" constraints such as the ones considered in the paper. We present an overview of key ideas related to robust continuous time envelope constrained filter design.
W artykule zaprezentowano metodę strojenia, pozwalającą na uniknięcie problemu zapewnienia kontaktu elektrycznego w układach strojenia filtrów na bazie linii SLP. Układ proponowanego strojnika nie wymaga kontaktu elektrycznego z obudową filtru i bazuje na idei kondensatora cylindrycznego z ruchomą częścią wewnętrzną. W artykule, oprócz zasady działania układu, zaprezentowano również wyniki symulacji i pomiarów modelowego pięciostopniowego filtru grzebieniowego w paśmie L/S.
EN
The article comprises an approach to avoiding the problem of obtaining the electrical contact in typical tuners for stripline-based filters. The tuner structure shown here does not require any electrical contact and is based on the concept of the cylindrical capacitor with a sliding inner part. The idea of the construction and working principle are shown together with a simulation and measurement results fora manufactured model of 5' order combline L/S-band filter.
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In this paper a theory of ideals and filters m some kind of ring-like structures, namely in generalized Boolean quasirings (GBQRs), is presented. We refer to weak distributivity in GBQRs, too.
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Obracające się części maszyn i urządzeń generują drgania o szerokim widmie częstotliwości, które są źródłem informacji wykorzystywanej w diagnostyce. Szczególne znaczenie w procesie diagnozowania mają składowe synchroniczne ze źródłem pobudzenia. Powszechnie znane są uniwersalne programy umożliwiające zamianę przebiegu w dziedzinie czasu na przebieg w dziedzinie częstotliwości (analiza Fouriera). Ich zastosowanie do pomiaru drgań synchronicznych ze źródłem pobudzenia jest ograniczone ze względu na niestabilność częstotliwości sygnału pobudzającego np. turbiny silnika. W pracy na przykładach z wykorzystaniem sygnału przyspieszenia wibracji silnika K-15 wykazano, że w przypadku gdy w poddanym analizie przedziale czasu, częstotliwość analizowanego przebiegu podlega zmianie, jednej rzeczywistej składowej w dziedzinie częstotliwości odpowiada kilka dyskretnych składowych przebiegu wyjściowego analizy Fouriera. W sytuacji gdy poziomy mierzonych przebiegów są małe wyodrębnienie ich jest niemożliwe. Zjawisko rośnie ze wzrostem rzędu harmonicznej. Wykazano, że zastosowanie filtrów śledzących umożliwia wydzielenie składowych synchronicznych z sygnałem pobudzającym oraz eliminację dla składowych synchronicznych z sygnałem pobudzającym, omówionego powyżej zjawiska rozszczepiania (zwielokratniania) składowych. Przedstawiono ocenę przydatności zastosowania zespołu cyfrowych filtrów śledzących do pomiaru drgań jednowirnikowego turbinowego silnika odrzutowego.
EN
A total frequency spectrum of rotating elements conteins a great deal of interesting and valuable information. The most valuable components are synchronous with rotating elements. There are a lot of universal programs for changing time-domain signals into frequency-domain signals (Fourier transform analysis). Their applications to measurement of synchronous with a source of vibration components are limited due to frequency unstability of the source of vibration.The paper using vibration acceleration signals of the K-15 turbine engine presents that when frequency of an analysing signal is changing one physicaly existing frequency signal component has a few counterparts in Fourier transform analysis. As the rate of harmonics increases the phenomenon increases. Using of narrow-band tracking filters anables extractions of synchronic components and elimination stated above phenomenon. The papers presents usability evaluation of implementation narrow-band tracking filters to measurement of vibration of a gas turbine engine.
We deal with congruences on semilattices with section antitone involution which rise e.g., as implication reducts of Boolean algebras, MV-algebras or basic algebras and which are included among implication algebras, orthoimplication algebras etc. We characterize congruences by their kernels which coincide with semilattice filters satisfying certain natural conditions. We prove that these algebras are congruence distributive and 3-permutable.
Characterizations of IF-filters of a pseudo-BL-algebra are established. Some related properties are investigated. The notation of prime IF- filters and a characterization of a pseudo-BL-chain are given. Homomorphisms of IF-filters and direct product of IF-filters are studied.
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The infimum of elements a and b of a Hilbert algebra are said to be the compatible meet of a and b, if the elements a and b are compatible in a certain strict sense. The subject of the paper will be Hilbert algebras equipped with the compatible meet operation, which normally is partial. A partial lower semilattice is shown to be a reduct of such an expanded Hilbert algebra i ?both algebras have the same ?lters.An expanded Hilbert algebra is actually an implicative partial semilattice (i.e., a relative subalgebra of an implicative semilattice),and conversely.The implication in an implicative partial semilattice is characterised in terms of ?lters of the underlying partial semilattice.
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