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- Jorge Sánchez Valverde, Rolf-Rainer Grigat
- ICIP
- 2000

We present a high quality solution to the binarization problem of technical document images. The method is based on locally adaptive methods without the need of manual interaction or tuning. The algorithm includes Niblack's binarization and two validation steps based on morphological image processing and gradient based decisions. Our result has the… (More)

- J. T. Lunardia, L. A. Manzoni, B. M. Pimentel, J. S. Valverde
- 2000

In this paper we consider the scalar sector of Duffin-Kemmer-Petiau theory in the framework of Epstein-Glaser causal method. In this context we calculate the two point distributions for Compton scattering and vacuum polarization. We also recover, in a natural way, the scalar propagator of the usual effective theory. ∗On leave from Universidade Estadual de… (More)

Two problems relative to the electromagnetic coupling of Duffin-Kemmer-Petiau (DKP) theory are discussed: the presence of an anomalous term in the Hamiltonian form of the theory and the apparent difference between the Interaction terms in DKP and Klein-Gordon (KG) Lagrangians. For this, we first discuss the behavior of DKP field and its physical components… (More)

- J S Valverde, Onofre Rojas, S M de Souza
- Physical review. E, Statistical, nonlinear, and…
- 2009

We study a two-dimensional XXZ -Ising model on a square-hexagon (denoted for simplicity by 4-6) lattice with spin 1/2. The phase diagram at zero temperature is discussed, where five states are found, two types of ferrimagnetic states, two types of antiferromagnetic states, and one ferromagnetic state. To solve this model, we have mapped onto the… (More)

- J S Valverde
- Physical review. E, Statistical, nonlinear, and…
- 2012

In this work we study a two-dimensional XXZ-Ising spin-1/2 model with quartic interactions. The model is composed of a two-dimensional lattice of edge-sharing unitary cells, where each cell consists of two triangular prisms, converging in a basal plane with four Ising spin-1/2 (open circles); the apical positions are also occupied by four Heisenberg… (More)

We give an action for the massless spinning particle in pseudoclassical mechanics by using grassmann variables. The constructed action is invariant under τ -reparametrizations, local SUSY and O(N) transformations. After quantization, for the special case N = 2, we get an action which describes the spin 0, 1 particles and topological sectors of the massless… (More)

- J. S. Valverde
- 2003

We prove the equivalence of many-photon Green functions in statistical quantum field Duffin-Kemmer-Petiau (DKP) and Klein-GordonFock (KGF) theories using functional path integral formalism for partition functional in statistical quantum (finite temperature) field theory. We also calculate the polarization operators in these theories in oneloop… (More)

- J. S. Valverde
- 2003

The thermodynamical partition function of the Duffin–Kemmer–Petiau theory is evaluated using the imaginary-time formalism of quantum field theory at finite temperature and path integral methods. The DKP partition function displays two features: (i) full equivalence with the partition function for charged scalar particles and charged massive spin 1… (More)

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