We study algebraic properties of categories of Merotopic, Nearness, and Filter Algebras. We show that the category of filter torsion free abelian groups is an epireflective subcategory of the category of filter abelian groups. The forgetful functor from the category of filter rings to filter monoids is essentially algebraic and the forgetful functor from the category of filter groups to the cat...

in this article we introduce the concept of $z^circ$-filter on a topological space $x$. we study and investigate the behavior of $z^circ$-filters and compare them  with corresponding ideals, namely, $z^circ$-ideals of $c(x)$,  the ring of real-valued continuous functions on a completely regular hausdorff space $x$. it is observed that $x$ is a compact space if and only if every $z^circ$-filter ...

In this paper, we proposed a novel structure for designing all optical filter based on photonic crystal structure. In designing the proposed filter, we simply employed a point defect localized between input and output waveguides as wavelength selecting part of the filter. The initial form of this filter is capable of selecting optical waves at =1560 nm, the transmission efficiency of the filte...

In this paper, a special preprocessing operations (filter) is proposed to decrease the effects of noise of textures. This filter using average of circular neighbor points (Cmean) to reduce noise effect. Comparing this filter with other average filters such as square mean filter and square median filter indicates that it provides more noise reduction and increases the classification accuracy...

in this paper, using annular resonator we have designed an adding and dropping filter light based ontwo-dimensional photonic crystals. the shape of ring resonator filter adding and dropping that wehave proposed is race track. this filter has a hexagonal lattice structure of silicon bars withrefractive index 3/46 that is located in the context of air with refractive index 1. transmissionefficien...

in this paper, a novel matched filter based on a new kernel function with cauchy distribution is introduced to improve the accuracy ofthe automatic retinal vessel detection compared with other available matched filter‑based methods, most notably, the methods builton gaussian distribution function. several experiments are conducted to pick the best values of the parameters for the new designedfi...

background: in myocardial perfusion spect imaging, images are degraded by photon attenuation, the distance-dependent collimator, detector response and photons scatter. filters greatly affect quality of nuclear medicine images materials and methods: a phantom simulating heart left ventricle was built. about 1mci of 99mtc was injected into the phantom. images were taken from this phantom. some fi...

In this paper, first we study the semi maximal filters in linear $BL$-algebras and we prove that any semi maximal filter is a primary filter. Then, we investigate the radical of semi maximal filters in $BL$-algebras. Moreover, we determine the relationship between this filters and other types of filters in $BL$-algebras and G"{o} del algebra. Specially, we prove that in a G"{o}del algebra, any ...

periodic noises are unwished and spurious signals that create repetitive pattern on images and decreased the visual quality. firstly, this paper investigates various methods for reducing the effects of the periodic noise in digital images. then an adaptive optimum notch filter is proposed. in the proposed method, the regions of noise frequencies are determined by analyzing the spectral of noisy...