PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 22

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
1
Study and adjustment of dermoscopic image processing algorithms for lesion border detection
Borys D., Szeremet M., Psiuk-Maksymowicz K., Ostrowski Z., Frąckiewicz M.
Studia Informatica
|
2016
|
Vol. 37, nr 3B
33-46
EN
The goal of our work was an initial preprocessing of dermoscopic images towards accurate lesion border detection. Four algorithms were proposed and analyzed: MS – algorithm using mean shift clustering, HE – algorithm using histogram equalization, TTH – algorithm using the top-hat transform, PCA – algorithm using principal component analysis. Those algorithms were tested on PH2 images database that contains 200 dermoscopic images, each with a mask of the lesion. Those algorithms were optimized using lesion mask from database and Jaccard index as a measure of similarity of both sets. Simple statistical analysis of indexes was used to compare proposed algorithms in term of their accuracy.
PL
W artykule poruszono problem wstępnego przetwarzania obrazów dermatoskopowych w celu znalezienia konturu znamienia. Zaproponowano i porównano cztery algorytmy: MS – wykorzystujący klasteryzację ‘mean shift’, HE – wykorzystujący wyrównywanie histogramu, TTH – wykorzystujący transformację ‘top-hat’, PCA – wykorzystujący metodę analizy głównych składowych. Algorytmy przetestowano z wykorzystaniem obrazów z bazy PH2, zawierającej 200 obrazów wraz z obrysem ręcznym, a ich parametry dobrano optymalizując indeks Jaccarda. Proste statystyki wyników pozwoliły na porównanie proponowanych algorytmów.
2
Comparison of three In silico models of heat transfer in human body exposed to mild cooling
Buliński P., Ostrowski Z., Adamczyk W.
Studia Informatica
|
2016
|
Vol. 37, nr 3A
31--42
EN
The comparison of three numerical models of skin undergoing thermal stimulation in a human forearm is presented. Small brass compress is used to cool tissues, followed by the analysis of the skin temperature recovery process. In silico generated results are validated against in vivo measurements on 8 male adults.
PL
W pracy przedstawiono porównanie trzech modeli numerycznych tkanek przedramienia poddanych stymulacji termicznej. Chłodzenie skóry zrealizowano za pomocą mosiężnego kompresu. Analizowano proces powrotu schłodzonej skóry do warunków równowagi termicznej. Wyniki symulacji in silico porównano z pomiarami in vivo wykonanymi dla grupy 8 dorosłych mężczyznach.
3
CFD analysis of blood flow within aorta of patient with coarctation of aorta
Rojczyk M., Ostrowski Z., Adamczyk W., Melka B., Bandoła D., Gracka M., Knopek A., Golda A., Nowak A. J.
Studia Informatica
|
2016
|
Vol. 37, nr 3A
43--55
EN
Blood flow in a real geometry of aorta was analysed. The CFD analysis was performed using commercial ANSYS/Fluent code. Velocity profile was used to mimic inlet flow conditions during human cardiac cycle. Outlet pressure boundary condition was coupled with lumped parameter model (electrical analogy) of circulatory system.
PL
Przeanalizowano jednofazowy przepływ krwi dla modelu aorty odwzorowującego rzeczywistą geometrię. Symulacja CFD przeprowadzona była za pomocą komercyjnego oprogramowania ANSYS/Fluent. Na wlocie do geometrii zadano profil prędkości, odpowiadający cyklowi pracy serca. Ciśnienie krwi na wylotach określono przez sprzężenie z parametrycznym modelem skupionym (zbudowanym w analogii elektrycznej).
4
Content available remote Numerical model of heat transfer in skin lesions
Ostrowski Z., Buliński P., Adamczyk W., Kozołub P., Nowak A. J.
Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika
|
2015
|
z. 87 [291], nr 1
55--62
EN
Preliminary results of numerical modelling of skin undergoing thermal stimulation (mild cooling) in a human forearm is presented. Small brass compress was used for cooling purposes. The skin recovery process was then analysed. Temperature history for N = 14 samples was recorded using IR camera. The samples come from 8 male adults (age 25-38 years). A numerical model of heat transfer in tissues and CFD model of surrounding air (natural convection) was proposed. Simulation results were validated against experimental data.
PL
W pracy zaprezentowano wstępne wyniki modelowania numerycznego procesów wymiany ciepła w rejonie skóry przedramienia poddanej termostymulacji (łagodnego ochładzania). Do ochładzania użyto kompresów mosiężnych. Przeanalizowano proces powrotu skóry do stanu sprzed termostymulacji. Przy użyciu kamery termowizyjnej zarejestrowano rozkład temperatury dla N = 14 próbek w grupie 8 przebadanych dorosłych mężczyzn (w wieku 25-38 lat). Zaproponowano model numeryczny przepływu ciepła w tkankach przedramienia oraz w otaczającym je powietrzu (w warunkach konwekcji swobodnej). Wyniki symulacji zostały poddane walidacji przy użyciu danych pochodzących z pomiarów.
5
Content available remote Modelling and validation of transient heat transfer processes in human skin undergoing local cooling
Ostrowski Z., Buliński W., Adamczyk W., Nowak A. J.
Przegląd Elektrotechniczny
|
2015
|
R. 91, nr 5
76-79
EN
The analysis of transient heat transfer processes in human forearm skin undergoing local thermal stimulation (mild cooling by means of brass compress) is presented. A numerical model of heat transfer within: living tissues (Pennes bioheat equation) and metal compress used for skin cooling is proposed. Simulation results were validated against in vivo measurement data of heat flux and compress temperature for N=8 samples in four male adults (age 25–38 years).
PL
W pracy przedstawiono analizę niestacjonarnych procesów wymiany ciepła w skórze przedramienia poddanej lokalnej termostymulacji (łagodnego ochładzania przy pomocy mosiężnych kompresów). Zbudowano model numeryczny procesów przepływu ciepła w: tkankach (równanie biociepła Pennes’a) oraz kompresie używanym do chłodzenia. Otrzymane wyniki poddano walidacji na podstawie pomiarów in vivo gęstości strumienia ciepła oraz temperatury kompresu dla N=8 próbek w grupie czterech przebadanych dorosłych mężczyzn w wieku 25-38 lat.
6
Content available remote Validation of a numerical model of locally cooled tissues
Buliński P., Ostrowski Z., Adamczyk W., Fityka A., Nowak A. J.
Computer Assisted Methods in Engineering and Science
|
2015
|
Vol. 22, no. 4
305--314
EN
Measurements of heat transfer and temporal temperature distribution can be used as input in the diagnostic tools and methods of skin lesions, with special attention paid to malignant melanoma identification. Such approach requires mutual use of skin temperature and heat flux measurements combined with numerical simulation. A mild skin cooling process by a brass compress is considered in this paper. The temperature distribution on the skin and the heat flux between metal and tissues are measured. They are used in the course of validation study of the proposed numerical model. A numerical model of heat transfer in living tissues is described by Pennes’ bioheat equation augmented with additional models of passive thermoregulation and vasoconstriction effects. The information regarding material properties of tissues and cooling compress involved in the simulation is essential to accurately solve this problem. Therefore, the main purpose of this work is to determine the accurate material property information by means of laboratory experiments.
7
Content available remote Inverse heat transfer problems: an application to bioheat transfer
Rojczyk M., Orlande H. R. B., Colaço M. J., Szczygieł I., Nowak A. J., Białecki R. A., Ostrowski Z.
Computer Assisted Methods in Engineering and Science
|
2015
|
Vol. 22, no. 4
365--383
EN
In this work, we applied the Markov chain Monte Carlo (MCMC) method for the estimation of parameters appearing in the Pennes’ formulation of the bioheat transfer equation. The inverse problem of parameter estimation was solved with the simulated transient temperature measurements. A one-dimensional (1D) test case was used to explore the capabilities of using the MCMC method in bioheat transfer problems, specifically for the detection of skin tumors by using surface temperature measurements. The analysis of the sensitivity coefficients was performed in order to examine linear dependence and low sensitivity of the model parameters. The solution of the direct problem was verified with a commercial code. The results obtained in this work show the ability of using inverse heat transfer analysis for the detection of skin tumors.
8
Content available remote Infant care bed natural convection heat transfer coefficient – measurements and estimation
Ostrowski Z., Rojczyk M., Łaszczyk J., Szczygieł I., Kaczmarczyk J., Nowak A. J.
Przegląd Elektrotechniczny
|
2014
|
R. 90, nr 5
122--125
EN
The energy balance and heat exchange for newborn baby in infant care bed environment (radiant warmer) are considered. Convective and radiant heat losses from an infant in radiant warmer were studied using copper cast anthropomorphic thermal manikin and controlled climate chamber setup. The total body heat loss was measured for several mean skin and ambient temperatures, leading to total heat transfer coefficient estimation.
PL
Rozważany jest bilans energii oraz mechanizmy wymiany ciepła dla noworodka w otwartym inkubatorze dla niemowląt. Wykorzystano miedziany antropomorficzny manekin termiczny noworodka do zbadania konwekcyjnej i radiacyjnej wymiany ciepła z otoczeniem w komorze klimatycznej. Zmierzono całkowity strumień traconego ciepła dla wybranych średnich temperatur skóry oraz otaczającego powietrza, a następnie wyznaczono konwekcyjny współczynnik wnikania ciepła.
9
Content available Modernization of ASW sonar SQS-56 at Gdansk University of Technology
Marszal J., Schmidt J., Salamon R., Kilian L., Raganowicz A., Zachariasz K., Ostrowski Z., Jedel A., Rudnicki M., Sidorko T.
Hydroacoustics
|
2010
|
Vol. 13
191-196
EN
The fast development of electronic technology and digital signal processing methods makes electronic devices, including sonar systems ones, obsolete very quickly. On the other hand the ships mechanical components including mechanical parts of sonars are operational for a few dozens of years. It makes good opportunity to modernize these devices by using modern electronic devices and new digital signal processing methods with application of existing antenna and mechanical systems. The paper presents the modernization of ASW sonar SQS-56 on the Polish frigate ORP “Kościusko”. The aim of modernization, the new parameters of the sonar and block diagram after modernization are presented.
10
Content available Bearing errors in passive sonar stationary target location
Schmidt A., Marszal J., Salamon R., Jedel A., Ostrowski Z.
Hydroacoustics
|
2009
|
Vol. 12
189-200
EN
The paper presents a method for determining the coordinates of stationary targets using passive sonar bearing. It identifies the requirements sonar movements must meet to keep the incorrect determination of coordinates to a minimum. It gives the relations, which help determine coordinate errors analytically. Numerical experiments are used to demonstrate the success of the analysis.
11
Zastosowanie techniki POD do identyfikacji prędkości wody gruntowej w obszarze zamrażania gruntu na podstawie pomiarów temperatury
Fic A., Ostrowski Z.
Modelowanie Inżynierskie
|
2008
|
T. 5, nr 36
71-78
PL
W pracy wykorzystano technikę POD i funkcje radialne do symulacji temperatury wykorzystywanej w algorytmie estymacji prędkości brzegowej wody gruntowej. Rozpatrywany w układzie dwuwymiarowym problem dotyczy nieustalonego procesu wymiany ciepła w gruncie podczas jego zamrażania poprzedzającego drżenie szybu. Analizowane w zmiennych bezwymiarowych zagadnienie odwrotne sprowadza się do estymacji liczby Pecleta na podstawie pomiarów temperatury bezwymiarowej.
EN
The POD technique and radial basis functions have been applied in the algorithm for estimation of the inlet groundwater velocity. The considered 2D problem concerns unsteady heat transfer in the ground which is frozen before shaft drilling. An inverse problem analyzed in the dimensionless variables reduces to estimation the Peclet number based on measurements of the dimensionless temperature.
12
Artificial intelligence optimisation of gas turbine systems
Smołka J., Liszka M., Ostrowski Z., Nowak A., Ziębik A.
Prace Naukowe Politechniki Warszawskiej. Konferencje
|
2007
|
T. 2, z. 25
529-537
EN
It is commonly accepted that inside the whole European Union within the next 15 years signiflcant investments are expected in both the electricity production as well as in energy transfers. Such investments will need the precise decision-making processes, supported with very versatile engineering tools. The major objective of this paper is to propose an application of a new methodology to design of power systems in a fuIly automatic way. The proposed methodology utilises the current artificial intelligence tools like genetic algorithm, artificial neural networks, expert systems, fuzzy logic toolbox, etc.
13
Content available Time variable gain for long range sonar with chirp sounding signal
Marszal J., Ostrowski Z., Schmidt J., Kilian L., Jedel A., Schmidt A.
Hydroacoustics
|
2007
|
Vol. 10
117-122
EN
The main purpose of applying Time Variable Gain (TVG) in active sonars with digital signal processing is to reduce dynamic range of echo signal and adapt it to the dynamic range of the analogue to digital conversion. With high transmission losses level, the dynamic range of the input signal in long range sonars can be very high and even exceed 200 dB. When chirp sounding signals with matched filtration are used, sonars can reach very long ranges. The article presents optimisation of TVG control for long range sonars. It also looks at the influence of chirp sounding signal compression, the result of digital matched filtration, for the TVG controlling. The examples of obtained results are presented.
14
Content available remote AI tool for automatic synthesis of CHP systems
Ostrowski Z., Liszka M., Smołka J., Ziębik A., Nowak A. J.
Computer Assisted Mechanics and Engineering Sciences
|
2007
|
Vol. 14, No. 4
705-714
EN
Inside the EU countries significant investments are expected in both the electricity production and energy transfers within the next 15 years. Such investments will need the precise decision-making processes, supported with very versatile engineering tools. The major objective of this paper is to propose an application of a new methodology to design power systems in a fully automatic way. The proposed methodology utilizes such artificial intelligence tools like genetic algorithms and expert systems.
15
Content available Dynamic control of the receiving beam horizontal cross-section in the side scan sonar
Jedel A., Kilian L., Marszal J., Ostrowski Z., Salamon R.
Hydroacoustics
|
2005
|
Vol. 8
69-76
EN
A decade old side scan sonars are now being modernised by way of dynamically controlling the width of the receiving beam in the horizontal cross-section. The result is a quasi-constant linear resolution of the sonar (replacing constant angular resolution), when it picks up echo signals as it moves further away from the targets. The advantage of the treatment is that the ship using the side scan sonar can increase its speed without risking the loss of near targets’ echo. The articles describes how the system of dynamic control was implemented. Special TVG systems were introduced to control dynamic signal gain from several separate sections of the sonar’s acoustic array, which was divided symmetrically into unequal sections. The location of these systems in the sonar’s receiver is presented. Examples are given of curves that control TVG and of the effects of dynamic horizontal stabilisation of the sonar’s linear resolution as it receives signals.
16
Content available Hydrographic echosounder for sounding inland waters
Jedel A., Kilian L., Marszal J., Ostrowski Z., Wojan Z., Zachariasz K.
Hydroacoustics
|
2004
|
Vol. 7
89-96
EN
This article describes a new echosounder model designed specifically for institutions responsible for the management of inland waterways, artificial and natural reservoirs, and marine coastal waters. The basic requirement related to the need of sounding shallow waters is measuring the smallest possible depths. Using separate transducers (sending and receiving) and attenuating them, and introducing a high dynamic range TVG circuit allowed the measurement of depths from 20cm at a maximum range of 100m. Water temperature is measured in order to include sound velocity corrections. The echosounder is manufactured using modern technology, with a PC 104 computer, robust FLASH memory emulating a hard disk, 8 inch color LCD panel, thermal printer with paper band for instant profile printouts, and a floppy disk drive for permanent storage. The echosounder interfaces to GPS.
17
Content available Autonomous hydroacoustic sound velocity profiler
Jedel A., Marszal J., Ostrowski Z., Kilian L.
Hydroacoustics
|
2003
|
Vol. 6
261--266
EN
The paper presents the autonomous hydroacoustic sound velocity profiler collaborating with ordinary PC by small box included interface & battery charger. The measurement and calibration methods and block diagram of the meter are presented as well as principles of operation, data collection, selection and transmission. There are described three versions of this meter - dropped from "normal" ships, installed in the light hull of submarines and casings in the hulls of variable depth sonar antennas.
18
Zastosowanie algorytmu ewolucyjnego MEB do optymalizacji kształtu elementów termosprężystych z uwzględnieniem promieniowania
Białecki R. A., Ostrowski Z., Burczyński T., Długosz A.
Prace Naukowe Politechniki Warszawskiej. Konferencje
|
2002
|
T. 1, z. 22
75-82
PL
Praca dotyczy optymalizacji kształtu ciała sprężystego i przewodzącego ciepło. Ciało to wymienia ciepło z otoczeniem na drodze promieniowania i konwekcji, może być wieło-spójne a jego powierzchnie mogą się wzajemnie opromieniowywać. Zadanie promieniowania uwzględnienia występowanie stref zacienionych. W zadaniu termospręźystości uwzględnia się tytko wpływ poła temperatury na połę naprężeń. Zarówno zadanie przewodzenia ciepła, sprzężone z rozwiązaniem problemu promieniowania, jak i zadanie sprężystości są rozwiązywane metodą elementów brzegowych. Do rozwiązywania zadania optymalizacji kształtu użyto algorytmu ewolucyjnego. Łatwość modyfikacji siatek w MEB pozwała na prostą automatyzację obliczeń ewolucyjnych. Sama procedura optymalizacyjna cechuje się dużą elastycznością i odpornością na obecność łokałnych ekstremów.
EN
Shape optimization of heat conducting, elastic bodies subjected to thermal and standard loads is considered. Interaction of stress and temperature fields is modelled using the formulation of uncoupled steady state thermoelasticity. The presence of heat radiation with mutual irradiation of the boundaries and the presence of shadow zones is taken into account. To find the optimal shape evolutionary algorithm is used. The boundary element method is applied to discretize the thermoelasticity, conduction and radiation problems.
19
Content available Special forms of echo visual representation in an ahead looking sonar
Raganowicz A., Kilian L., Ostrowski Z.
Hydroacoustics
|
2002
|
Vol. 5
47--52
EN
The paper discusses ways to organise visual representation in a multi-beam ahead looking sonars whose function is to detect objects on the bottom and in pelagic zones. Forms of visual representation are shown and illustrated on the basic screen (panoramic representation and setting, alarms) and on the auxiliary screen (type A, B and special). Special forms of visual representation are mainly used in detecting objects in difficult hydrological conditions and when classifying objects. Several types of visual representations are shown, including a historical data example, multiplied type A representation in multiple beams and two types of quasi-spatial displays.
20
Redukcja wzajemnych zakłóceń w sonarach impulsowych z modulacja częstotliwości
Jedel A., Salamon R., Marszal J., Kaczmarek J., Ostrowski Z.
Prace Naukowe Instytutu Telekomunikacji i Akustyki Politechniki Wrocławskiej. Konferencje
|
2001
|
Vol. 83, nr 27
281-284
EN
Some of important disturbances in sonar echo are signals emitted by the other sonars. Sonar receives these signals by the direct trace or as echoes from the targets. The mutual interference level depends on many parameters, like: the sounding frequency bands aliasing, the distance between sonars and the mutual localization of sonar transducers. The mutual interference of sonars is particularly sharp when the same type of sonars (with the same frequency bands) is used in the same area The analysis of such situations is presented in the paper. Some solutions of mutual interference reduction for pulse sonars with linear frequency modulation and match filtering with FFT technique, designed in Technical University of Gdansk, are given. The results of computer simulations are presented. It is possible to obtain the 40 dB reduction of mutual interference.
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.