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Mostrando ítems 1-10 de 19

#### Usefulness of cutting planes in the hierarchical segmentation of cardiac anatomical structures

(IOP Publishing, 2019)

A spatial geometric plane is defined by the three-dimensional coordinates of a pair of
spatial points and the direction that the normal vector establishes, which is formed by joining
those points by means of an oriented line segment. This type of planes, in three-dimensional
images, is extremely useful as an alternative solution to the problem of low contrast that exhibit
the anatomical structures present in cardiac computed tomography images. To do this, after using
a predetermined filter bank and in order to define a region of interest, a ...

#### Newton-Raphson method initialization for non-analytical equations solution linked to anticipated annuities

(IOP Publishing, 2019)

The series of payments made in equal intervals of time is known, in the world of
financial mathematics, as an annuity. An anticipated annuity is one whose periodic payment
expires at the beginning of the established payment interval. The non-analytical equation that
allows us to calculate the interest rate, linked to the anticipated annuity, can be solved using
several numerical methods, in particular, the numerical method called Newton-Rhapson. The
main problem with this method is its initialization, which requires of one starting point ...

#### Pulmonary adenocarcinoma characterization using computed tomography images

(IOP Publishing, 2019)

Lung cancer is one of the pathologies that sensitively affects the health of human
beings. Particularly, the pathology called pulmonary adenocarcinoma represents 25% of all lung
cancers. In this research, we propose a semiautomatic technique for the characterization of a
tumor (adenocarcinoma type), present in a three-dimensional pulmonary computed tomography
dataset. Following the basic scheme of digital image processing, first, a bank of smoothing filters
and edge detectors is applied allowing the adequate preprocessing over the dataset ...

#### Smart operator for the human liver automatic segmentation, present in medical images

(IOP Publishing, 2019)

The segmentation of the human body organ called liver is a highly challenging problem due to the noise, artifacts and the low contrast exhibited by the anatomical structures located around the liver and that are present in digital images, generated by any modality of medical images. The main modalities are: ultrasound, nuclear emission, magnetic resonance and the gold standard called multi-slice computed tomography. In this paper, with the objective of to address this problem, we consider multi-slice computed tomography images and we propose an ...

#### Usefulness of digital images segmentation in pulmonary transplantation

(IOP Publishing, 2019)

In the presence of pulmonary pathologies such as chronic obstructive pulmonary
disease, diffuse pulmonary disease and cystic fibrosis, among others, it is common to require
the removal or replacement of a portion of lungs. There are several requirements for both
donors and organ receivers (recipients) established in the literature. May be the main one is the
volume that the donor's lungs occupy in the thoracic cavity. This parameter is vital because if
the volume of the lungs exceeds the thoracic cavity of the recipients the transplant, ...

#### Use of computational realistic models for the cardiac ejection fraction calculation

(IOP Publishing, 2019)

Ejection fraction is one of the most useful clinical descriptors to determine the cardiac
function of a subject. For this reason, obtaining the value of this descriptor is of vital importance
and requires high precision. However, in the clinical routine, to generate the mentioned
descriptor value, a geometric hypothesis is assumed, obtaining an approximate value for this
fraction, usually by excess, and which is a dependent-operator. The aim of the present work is
to propose the accurate calculation of the ejection fraction from realistic ...

#### Mathematical argumentation in the classroom

(IOP Publishing, 2019)

The article shares some elements of comprehensive type about "mathematical
argumentation in the classroom"; whose analysis, was made from two fundamental categories
in the development of an oral mathematical argumentation process for the conviction,
contradiction and validation of a written mathematical argumentation process. The research
addressed two central categories of argumentation as a discursive form, the first one is the
epistemic position, and the second one is the discursive position that students unveil at the time
of mathematically ...

#### Space-occupying lesions identification in mammary glands using a mixed computational strategy

(IOP Publishing, 2019)

Abstract. The mammary pathology can manifest itself in multiple ways and originates spaceoccupying
lesions. The breast cancer is a space-occupying lesion, which is highly prevalent,
especially in women, and worldwide it is one of the leading causes of morbidity and mortality
in this population. The main image modality for breast cancer detection is the magnetic
resonance but this kind of image modality introduces several imperfections that affect the
image quality. Some of these imperfections or problems are: inhomogeneity in the ...

#### Large cells cancer volumetry in chest computed tomography pulmonary images

(IOP Publishing, 2019)

Lung cancer is the leading oncological cause of death in the world. As for
carcinomas, they represent between 90% and 95% of lung cancers; among them, non-small cell
lung cancer is the most common type and the large cell carcinoma, the pathology on which this
research focuses, is usually detected with the computed tomography images of the thorax.
These images have three big problems: noise, artifacts and low contrast. The volume of the
large cell carcinoma is obtained from the segmentations of the cancerous tumor generated, in a
semi-automatic ...

#### Interest rates calculation in certain ordinary annuities

(IOP Publishing, 2019)

Certain annuities are annuities whose payments occur on fixed dates; while a certain ordinary annuity is one in which payments are made at the end of each established period. The calculation of the interest rate, which governs the certain ordinary annuity, involves the use of a non-analytical equation that requires the application of numerical techniques to obtain the value of the aforementioned rate. The literature indicates that any of these techniques requires one or several numerical values for initialization, which generally are estimated ...