Wyniki wyszukiwania - BazTech

1

Direct proofs of intrinsic properties of prox-regular sets in Hilbert spaces

Konstantinov Matey, Zlateva Nadia

Journal of Applied Analysis

|

2023

|

Vol. 29, nr 1

143--149

EN

We provide new proofs of two intrinsic properties of prox-regular sets in Hilbert spaces.

2

Distance between two Keplerian orbits

Mohamed Ayman Homda, Dwidar Hany Ramdan, Adham Inal, Bakry Abd-Elazaz, El-Raffie Ahmed

Artificial Satellites : Journal of Planetary Geodesy

|

2021

|

Vol. 56, No. 3

57--77

EN

In this paper, constrained minimization for the point of closest approach of two conic sections is developed. For this development, we considered the nine cases of possible conics, namely, (elliptic-elliptic), (elliptic-parabolic), (elliptic–hyperbolic), (paraboli-elliptic), (paraboli-parabolic), (parabolic–hyperbolic), (hyperbolic-elliptic), (hyperbolic-parabolic), and (hyperbolic–hyperbolic). The developments are considered from two points of view, namely, analytical and computational. For the analytical developments, the literal expression of the minimum distance equation (S) and the constraint equation (G), including the first and second derivatives for each case, are established. For the computational developments, we construct an efficient algorithm for calculating the minimum distance by using the Lagrange multiplier method under the constraint on time. Finally, we compute the closest distance S between two conics for some orbits. The accuracy of the solutions was checked under the conditions that L|solution ≤ε1G||solution ≤ε2, where ε1,2 < 10 -10. For the cases of (paraboli-parabolic), (paraboli-hyperbolic), and (hyperbolic-hyperbolic), we studied thousands of comets, but the condition of the closest approach was not met.

3

Evaluation of Head Defect Images of Railway Rails in Laser Scatterometry

Lesiak P., Sokołowski A.

Problemy Kolejnictwa

|

2017

|

Z. 177

37--43

EN

The images of head checking faults of railway rails have been examined by laser scattering method. The studies used the functions of similarity and distance, both for binary images and multi-level quantized ones. The analysis was performed on the basis of numerical calculations, experimentally determined images of samples of these defects. These type of functions have proven extremely useful in evaluating these faults and can be used to classify them.

PL

Dokonano oceny obrazów wad szyn kolejowych typu head checking, zbadanych metodą skaterometrii laserowej. W badaniach wykorzystano funkcje podobieństwa i odległości, zarówno dla obrazów zbinaryzowanych, jak i skwantowanych wielopoziomowo. Analizę przeprowadzono na podstawie obliczeń numerycznych, wyznaczonych doświadczalnie obrazów próbek tych wad. Funkcje tego typu okazały się niezwykle przydatne w ocenie tych wad i mogą być wykorzystywane do ich klasyfikacji.

4

Applying the radiated emission to the specific emitter identification

Dudczyk J., Wnuk M., Matuszewski J.

Journal of Telecommunications and Information Technology

|

2005

|

nr 2

57-60

EN

During the last years we have observed fast development of the electronic devices and electronic warfare systems (EW). One of the most principal functions of the ESM/ELINT system is gathering basic information from the entire electromagnetic spectrum and its analysis. Simultaneously, utilization of some tools of artificial intelligence (AI) during the process of emitter identification is very important too. A significant role is played by measurement and signature intelligence (MASINT) based on non-intentional emission (calls-radiated emission). This emission is a source of knowledge about an analysed emitter due to its incidental "chemical", "spectral" traces and non-communication emitter's characteristics. The process of specific emitter identification (SEI) based on extraction of distinctive radiated emission features is presented by the authors. Specially important is utilization of a database (DB) in the process of identifying a detectable radar emission.

5

Optimised directional distance filter

Lukac R.

Machine Graphics and Vision

|

2002

|

Vol. 11, No. 2/3

311-326

EN

In this paper, a new adaptive directional distance filter especially for the impulse noise suppression in color images is provided. The proposed method takes advantage from the optimal filtering situation when only the affected samples are estimated, whereas noisy image points are passed to a filter output without change. For that reason, the proposed method is based on switching between the indentity filter (no smoothing) and the directional distance filter that provides a maximum amount of the smoothing. In order to achieve the most precise control of the proposed method, three center-weighted directional distance filters are utilised to determine a parameter compared with a threshold value. This simple comparison serves as a switching control. After the optimisation of the threshold, it will be shown that the proposed method achieves a significant improvement of the filter performance in comparison with standard vector filter classes for a wide range of impulse noise corruption.

6

Using Distance Functions to Solve Representation Choice Problems

Nguyen N.T.

Fundamenta Informaticae

|

2001

|

Vol. 48, nr 4

295-314

EN

A representation choice problem is based on the selection of an object (or objects), which should at best represent a given set of objects. In this paper we propose to solve this problem by using distance functions between objects. These distance functions are used to define representation choice functions. Six postulates for representation choice functions are given and their analysis is presented. The theoretical results provide us with some interesting relationships between classes of choice functions specified by the accepted postulates. They also make it possible to specify essential properties of considered choice functions. In particular, it has been proved that in practical settings it is suggested to use functions from two particular classes, for they preserve important features. Less popular representation choice functions are also pointed at and analyzed.

7

An image processing based study of the bone erosion process in osteoporosis using radiographic images : a shape metric approach

Majumdar D., Bhattacharya M.

Image Processing & Communications

|

1999

|

Vol. 5, no 2

39-55

EN

An investigation of a class of metabolic bone diseases called osteoporosis which is a very common bone disorder resulting a major disability is carried out with radiographic image modality for diagnostics and therapeutic planning. Based on a mathematical theory of shape authors developed a methodology to compute: (a) an erosion factor for different cases of osteoporosis; (b) a gradation of the disease so that doctor make some quantitative assessment and decide if the disorder can be treated conservatively or surgically.