491 research outputs found
Feature selection for classification of medical images of human tissue for cancer recognition
A statistical pattern recognition system for ultrasound medical images of prostatic tissue for cancer has been proposed. Using the autocorrelation method, the correct size of a statistical sliding window for feature extraction was defined. Known texture discrimination features have been tested for effectiveness. Another set of discriminating features, based on edge value distribution, Fourier power spectrum and wavelet transform has been derived and investigated. The set can be used as an input to a neural net classifier
On a class of three-dimensional integrable Lagrangians
We characterize non-degenerate Lagrangians of the form such that the corresponding Euler-Lagrange equations are integrable by the method of
hydrodynamic reductions. The integrability conditions constitute an
over-determined system of fourth order PDEs for the Lagrangian density ,
which is in involution and possess interesting differential-geometric
properties. The moduli space of integrable Lagrangians, factorized by the
action of a natural equivalence group, is three-dimensional. Familiar examples
include the dispersionless Kadomtsev-Petviashvili (dKP) and the Boyer-Finley
Lagrangians, and ,
respectively. A complete description of integrable cubic and quartic
Lagrangians is obtained. Up to the equivalence transformations, the list of
integrable cubic Lagrangians reduces to three examples, There exists a
unique integrable quartic Lagrangian, We
conjecture that these examples exhaust the list of integrable polynomial
Lagrangians which are essentially three-dimensional (it was verified that there
exist no polynomial integrable Lagrangians of degree five). We prove that the
Euler-Lagrange equations are integrable by the method of hydrodynamic
reductions if and only if they possess a scalar pseudopotential playing the
role of a dispersionless `Lax pair'. MSC: 35Q58, 37K05, 37K10, 37K25. Keywords:
Multi-dimensional Dispersionless Integrable Systems, Hydrodynamic Reductions,
Pseudopotentials.Comment: 12 pages A4 format, standard Latex 2e. In the file progs.tar we
include the programs needed for computations performed in the paper. Read
1-README first. The new version includes two new section
The Assembly of Hierarchs in Krasnoyarsk: Historical and Architectural Study
The article examines the stages of construction history of the Assembly of Hierarchs in Krasnoyarsk
that is a monument of architecture in the late XIX century. Archival documents and field studies of
the object have been used for this research. On the basis of documentary material, the role of the first
bishop of the Yenisei Diocese, Nicodemus, has been revealed in organizing and conducting activities
related to site selection for the Hierarchs town church in Krasnoyarsk, with its buildings, as well as the
design of interior decoration of residential buildings and chapel. A complex study design drawings of
buildings in initial and final stages of formation have been presented for the first time; their architectural
and planning analysis has been carried out. They allow us not only to discover creative proposals of
architects, but also trace the techniques of architectural projects in the XIX century. The names of
architects, who made up projects of structure and rebuilding homes for the Assembly of Hierarchs
in Krasnoyarsk in the pre-revolutionary period, have been revealed. These materials given in the
article make it possible to recreate an authentic architectural and planning structure of the Assembly
of Hierarchs and chapel and the elements of the decor with great accuracy nowadays. The results of
the study prove to have a great architectural and urban planning, historical and cultural value of the
Assembly of Hierarchs in Krasnoyarsk.В статье рассмотрены этапы строительной истории Архиерейского дома в Красноярске -
памятника архитектуры конца XIX века. Для исследования использованы архивные документы
и натурное изучение объекта. На основе документальных материалов выявлена роль
первого епископа Енисейской епархии, Никодима, в организации и проведении мероприятий,
связанных с выбором участка для архиерейского подворья в Красноярске, с его застройкой, а
также с оформлением внутреннего убранства жилых помещений и домовой церкви. Впервые
представлены проектные чертежи комплекса исследуемых зданий начального и завершающего
этапов формирования; проведен их архитектурно-планировочный анализ. Они позволяют
раскрыть не только творческие предложения зодчих, но и методы составления архитектурных
проектов в XIX веке. Выявлены фамилии архитекторов, составлявших в дореволюционный
период проекты устройства и перестройки дома для Архиерея в Красноярске. Приведенные
в статье материалы исследования позволяют с большой достоверностью воссоздать в
настоящее время подлинную архитектурно-планировочную структуру Архиерейского дома
и домовой церкви, элементы их декора. Результаты исследования подтверждают высокую
архитектурно-градостроительную и историко-культурную ценность Архиерейского дома в
Красноярске
Oriented Associativity Equations and Symmetry Consistent Conjugate Curvilinear Coordinate Nets
This paper is devoted to description of the relationship among oriented
associativity equations, symmetry consistent conjugate curvilinear coordinate
nets, and the widest associated class of semi- Hamiltonian hydrodynamic-type
systems.Comment: 19 page
Classification of integrable two-component Hamiltonian systems of hydrodynamic type in 2+1 dimensions
Hamiltonian systems of hydrodynamic type occur in a wide range of
applications including fluid dynamics, the Whitham averaging procedure and the
theory of Frobenius manifolds. In 1+1 dimensions, the requirement of the
integrability of such systems by the generalised hodograph transform implies
that integrable Hamiltonians depend on a certain number of arbitrary functions
of two variables. On the contrary, in 2+1 dimensions the requirement of the
integrability by the method of hydrodynamic reductions, which is a natural
analogue of the generalised hodograph transform in higher dimensions, leads to
finite-dimensional moduli spaces of integrable Hamiltonians. In this paper we
classify integrable two-component Hamiltonian systems of hydrodynamic type for
all existing classes of differential-geometric Poisson brackets in 2D,
establishing a parametrisation of integrable Hamiltonians via
elliptic/hypergeometric functions. Our approach is based on the Godunov-type
representation of Hamiltonian systems, and utilises a novel construction of
Godunov's systems in terms of generalised hypergeometric functions.Comment: Latex, 34 page
Staeckel systems generating coupled KdV hierarchies and their finite-gap and rational solutions
We show how to generate coupled KdV hierarchies from Staeckel separable
systems of Benenti type. We further show that solutions of these Staeckel
systems generate a large class of finite-gap and rational solutions of cKdV
hierarchies. Most of these solutions are new.Comment: 15 page
Integrable Systems and Metrics of Constant Curvature
In this article we present a Lagrangian representation for evolutionary
systems with a Hamiltonian structure determined by a differential-geometric
Poisson bracket of the first order associated with metrics of constant
curvature. Kaup-Boussinesq system has three local Hamiltonian structures and
one nonlocal Hamiltonian structure associated with metric of constant
curvature. Darboux theorem (reducing Hamiltonian structures to canonical form
''d/dx'' by differential substitutions and reciprocal transformations) for
these Hamiltonian structures is proved
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