BCI systems analyze the EEG signal and translate patient intentions into simple commands. Signal processing methods are very important in such systems. Signal processing covers: preprocessing, feature extraction, feature selection and classification. In the article authors present the results of implementing linear discriminant analysis as a feature reduction technique for BCI systems. Streszcz...

The regular open subsets of a topological space form Boolean algebra, where the join two sets is interior closure their union. A content finitely additive measure on this or one its subalgebras. We develop theory integration for such contents. then explain relationship between contents, residual charges, and Borel measures. show that can be represented by normal measure, augmented with liminal ...

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Let a and b be distinct positive integers. We show that the equation u + a · p = v + b · p has no solutions with u, v ∈ βN and p ∈ βN\N. More generally, we show that if (S,+) is any commutative cancellative semigroup and S has no nontrivial solutions to n · s = n · t for n ∈ N and s, t ∈ S, then the equation u + a · p = v + b · p has no solutions with u, v ∈ βS and p ∈ βS\S. We characterize com...

If f is an autohomeomorphism of some space X, then βf denotes its Stone-Čech extension to βX. For each n ≤ ω, we give an example of a first countable, strongly zerodimensional, subparacompact X and a map f such that every point of X has an orbit of size n under f and βf has a fixed point. We give an example of a normal, zero-dimensional X such that f is fixed-point-free but βf is not. We note t...

Let X be a completely regular space and let A(X) be a ring of continuous real-valued functions onX which is closed under local bounded inversion. We show that the structure space of A(X) is homeomorphic to a quotient of the Stone–Čech compactification of X. We use this result to show that any realcompactification of X is homeomorphic to a subspace of the structure space of some ring of continuo...

Eric van Douwen [5] produced a maximal crowded extremally disconnected regular space and showed that its Čech–Stone compactification is an at most two-to-one image of βN. We construct for any n = 3 an example of a compact crowded space Xn that is an image of βN under a map all of whose fibers have either size n or n− 1. We also show that under CH this is best possible.