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total: 932
Search results for: Mathematics
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Template chart detection for stoma telediagnosis
PublicationThe paper presents the concept of using color template charts for the needs of telemedicine, particularly telediagnosis of the stoma. Although the concept is not new, the current popularity and level of development of digital cameras, especially those embedded in smartphones, allow common and reliable remote advice on various medical problems, which can be very important in the case of limitations in a physical contact with a doctor....
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Customized crossover in evolutionary sets of safe ship trajectories
PublicationThe paper presents selected aspects of evolutionary sets of safe ship trajectories-a method which applies evolutionary algorithms and some of the assumptions of game theory to solving ship encounter situations. For given positions and motion parameters of the ships, the method finds a near optimal set of safe trajectories of all ships involved in an encounter. The method works in real time and the solutions must be returned within...
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Designing a ship course controller by applying the adaptivebackstepping method
PublicationThe article discusses the problem of designing a proper and efficient adaptive course-keeping control system for a seagoingship based on the adaptive backstepping method. The proposed controller in the design stage takes into account thedynamic properties of the steering gear and the full nonlinear static maneuvering characteristic. The adjustable parametersof the achieved nonlinear control structure were tuned up by using the...
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On a matching distance between rooted phylogenetic trees
PublicationThe Robinson–Foulds (RF) distance is the most popular method of evaluating the dissimilarity between phylogenetic trees. In this paper, we define and explore in detail properties of the Matching Cluster (MC) distance, which can be regarded as a refinement of the RF metric for rooted trees. Similarly to RF, MC operates on clusters of compared trees, but the distance evaluation is more complex. Using the graph theoretic approach...
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ADAPTIVE PREDICTIONS OF THE EURO/ZŁOTY CURRENCY EXCHANGE RATE USING STATE SPACE WAVELET NETWORKS AND FORECAST COMBINATIONS
PublicationThe paper considers the forecasting of the euro/Polish złoty (EUR/PLN) spot exchange rate by applying state space wavelet network and econometric forecast combination models. Both prediction methods are applied to produce one-trading-day- ahead forecasts of the EUR/PLN exchange rate. The paper presents the general state space wavelet network and forecast combination models as well as their underlying principles. The state space...
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Fuzzy logic gain scheduling for non - linear servo tracking
PublicationArtykuł zawiera propozycję strojenia jako metodę sterowania serwomechanizmem z silnie nieliniowymi elementami. Serwomechanizm steruje dwoma elementami układu śledzącego zamontowanymi na okręcie znajdującym się w morzu. W układzie występuje tarcie spoczynkowe przy zerowej prędkości oraz nieliniowe tarcie przeciwdziałające ruchowi w każdej z osi układu śledzącego. Zastosowany został podwójny układ sterowania ze sprzężeniem zwrotnym....
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Approximate and analytic flow models for leak detection and identification
PublicationThe article presents a comprehensive quantitative comparison of four analytical models that, in different ways, describe the flow process in transmission pipelines necessary in the task of detecting and isolating leaks. First, the analyzed models are briefly presented. Then, a novel model comparison framework was introduced along with a methodology for generating data and assessing diagnostic effectiveness. The study presents basic...
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A Measurable Selector in Kadison’s Carpenter’s Theorem
PublicationWe show the existence of a measurable selector in Carpenter’s Theorem due to Kadison. This solves a problem posed by Jasper and the first author in an earlier work. As an application we obtain a characterization of all possible spectral functions of shift-invariant subspaces of L 2 (R d ) and Carpenter’s Theorem for type I ∞ von Neumann algebras.
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Properties of sensorless control systems based on multiscalar models of the induction motor
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Slot harmonics in cage motors due to saturation of a main magnetic circuit
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Computer simulation of induction heating system with series inverter
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The stand for determining of thermal‐electrical material properties of induction heated charge
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The optimisation of induction heating system based on multiquadric function approximation
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Induction heating in estimation of thermal properties of conductive materials
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Implementation of power transformer controlled switching algorithm
PublicationThe article presents two new algorithms of controlled switching the power transformer. The main aim of the paper is to obtain formulas that determine the moments of closing of the circuit breaker poles. The study contains projects of control systems for both algorithms. Mathematical formulas for the time instants of the breaker poles closing were developed on the basis of electric circuit theory and magnetic circuit theory. The...
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Magnetic and infrared thermography methods in detection of antipersonnel landmines
PublicationIn this paper the two alternative methods of antipersonnel landmine detection are shown: the magnetic method and the active infrared thermography. The experimental results of the detection of selected, plastic mines using both methods are also presented.
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Broken rotor symptoms in the sensorless control of induction machine
PublicationThe purpose of this paper is to investigate the need for a universal method for sensorless controlled induction motor drive diagnosis. The increasing number of sensorless control systems in industrial applications require a universal method for the drive diagnosis, which provides reliable diagnostic reasoning independent of control system structure and state variables measurement or estimation method.Simulations and experimental...
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Nonlinear secondary arc model use for evaluation of single pole auto-reclosing effectiveness
PublicationPurpose – The purpose of this paper is to discuss two evaluation methods of single pole autoreclosing process effectiveness in HV transmission lines. Secondary arc current and recovery voltage results obtained by load flow calculation are compared to the results obtained by the time domain simulations. Moreover, a nonlinear secondary arc implementation is presented. Design/methodology/approach – A computer simulation studies were...
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Representation of magnetic hysteresis in a circuit model of a single-phase transformer
PublicationThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. The set of loop differential equations was developed for K-th winding transformer model where the flux linkages of each winding includes a flux common Φ to all windings as function of magneto motive force Θ of all windings. The first purpose of this paper is to determine a hysteresis nonlinearity involved...
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Broken rotor bar impact on sensorless control of induction machine
PublicationThe aim of the research is analysis of the sensorless control system of induction machine with broken rotor for diagnostic purposes. Increasing popularity of sensorless controlled variable speed drives requires research in area of reliability, range of stable operation, fault symptoms and application of diagnosis methods. T transformation (Cunha et al.,2003) used for conversion of instantaneous rotor currents electrical circuit...
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Properties of sensorless control systems based on multiscalar models of the induction motors
PublicationCelem artykułu jest opracowanie ogólnych postaci multiskalarnych modeli silnika indukcyjnego i zaprezentowanie właściwości bezczujnikowych układów regulacji opartych na takich modelach. Poprzednio prezentowane modele multiskalarne silnika indukcyjnego oparte na wykorzystaniu wektorów prądu stojana i strumienia wirnika zostły uogólnione jako model typu 1. Nowy model typu 2 zdefiniowany został dla wektora prądu stojana i innego wektora...
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Magnetic and capacitive couplings influence on power losses in double circuit high voltage overhead transmission line
PublicationPurpose – The paper aims to discuss problems of power and energy losses in a double-circuit overhead transmission line. It was observed from energymeters’ readings, that in such a line, active power losses can be measured as “negative”. The “negative” active power losses appear when the active power injected to the circuit is lower than the active power received at the circuit end. The purpose of this paper is to explain this phenomenon. Theoretical...
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Research of leakage magnetic field in deenergized transformer
PublicationThe article deals with the issue of the numerical analysis of the magnetic field occurring around the transformer after it has been powered down. The main goal of this analysis was to examine if it is possible to identify the residual fluxes in the transformer legs based on this fields’ measurements. It was also intended to determine the type and the location of magnetic sensors. Numerical analysis of the magnetic field was performed....
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Applying of thin plate boundary condition in analysis of ship’s magnetic field
PublicationThis paper presents computer simulations of ship’s magnetic signatures using a new thin plate boundary condition implemented in the Opera-3d 18R2 program. The paper aims to check the magnetic signatures’ numerical calculations precision of objects using the thin plate boundary conditions and analysis of the magnetic signature of ship with a degaussing system and with and without inner devices.
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Speed sensorless induction motor drive with motor choke and predictive control
PublicationArtykuł przedstawia układ napędowy z silnikiem indukcyjnym, zasilanym z falownika napięcia przy zastosowaniu filtru silnikowego. System pracuje bez czujnika prędkości obrotowej. Głównym aspektem pracy jest zwrócenie uwagi na to, że zastosowanie dławika silnikowego wymaga odpowiednich zmian w strukturach sterowania i estymacji zmiennych. Zaproponowano odpowiednie rozwiązanie dla układu napędowego z regulatorem predykcyjnym prądu....
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Mechanisms positioned in a neighbourhood of their singular positions - velocity amplification in the electromagnetic damping. Part 2. Numerical Verification
PublicationPraca prezentuje zagadnienia występujące podczas elektromagnetycznego tłumienia drgań układów mechanicznych. Analizowano zachowania układu ciągłego i jego drgania. Aby przyśpieszyć tłumienie, wprowadzono specjalny dwuramienny mechanizm umieszczony pomiędzy elementem drgającym i elementem tłumiącym drgania. Mechanizm ustawiony jest w pobliżu swojego ustawienia osobliwego. Aby określić potencjalny kierunek zmian prowadzący do poprawić...
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Mechanisms positioned in a neighbourhood of their singular positions - velocity amplification in the electromagnetic damping. Part 1 - Background of the mechanical structure modeling
PublicationW pracy przedstawiono metodę modelowania dynamiki drgającego hybrydowego układu mechanicznego złożonego z odkształcalnego podukładu ciągłego oraz z połączonego z nim mechanizmu. U układzie pojawiają się drgania części odkształcalnej. By je wytłumić, ich energia zamieniana jest w energię elektryczną (za pomocą prądnicy prądu stałego) i rozpraszana na oporności obecnej w układzie elektrycznym. Aby przyśpieszyć tłumienie, wprowadzony...
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Design advantages and analysis of a novel five-phase doubly-fed induction generator
PublicationPurpose – The purpose of this paper is to provide an analysis of the performance of a new five-phase doubly fed induction generator (DFIG). Design/methodology/approach – This paper presents the results of a research work related to fivephase DFIG framing, including the development of an analytical model, FEM analysis as well as the results of laboratory tests of the prototype. The proposed behavioral level analytical model is based...
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Improved methods for stator end winding leakage inductance calculation
PublicationCalculating the stator end-winding leakage inductance, taking into account the rotor, is difficult due to the irregular shape of the end-winding. The end-winding leakage may distribute at the end of the active part and the fringing flux of the air gap. The fringing flux belongs to the main flux but goes into the end-winding region. Then, not all the magnetic flux occurring in the end region is the end-winding leakage flux. The...
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State and control system variables sensitivity to rotor asymmetry in the induction motor drive
PublicationThe aim of this paper is to undertake analysis and comparison of the closed-loop and sensorless control systems sensitivity to the broken rotor for diagnostic purposes. For the same vector control system induction motor drive analysis concerning operation with the asymmetric motor, broken rotor fault handling and operation were investigated. Reliability, range of stable operation, fault symptoms and application of diagnosis methods...
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Jerzy Balicki dr hab. inż.
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Justyna Signerska-Rynkowska dr inż.
PeopleI am currently an assistant professor (adjunct) at Gdansk University of Technology (Department of Differential Equations and Mathematics Applications). My scientific interests include dynamical systems theory, chaos theory and their applications to modeling of biological phenomena, especially to neurosciences. In June 2013 I completed PhD in Mathematics at the Institute of Mathematics of Polish Academy of Sciences (IMPAN) (thesis...
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TWORZENIE TESTÓW Z MATEMATYKI Z WYKORZYSTANIEM PLATFORMY ENAUCZANIE
PublicationThe aim of the article is to present the use of the eNauczanie platform to create tests in mathematics after the first semester of mathematics at the Gdańsk University of Technology. Different types of questions will be discussed with special attention to questions that will allow to present mathematics content in an effective manner.
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Anita Maria Dąbrowicz-Tlałka dr
PeopleAnita Dąbrowicz-Tlałka graduated from the Faculty of Mathematics and Physics at the University of Gdańsk with an outstanding grade, having written her thesis in the field of geometric topology. She concurrently obtained a diploma in Postgraduate Studies in the Basics of Computer Science at the University of Gdańsk. In 2001 she received a Ph.D. degree in mathematical studies at the Poznań University of Technology after defending...
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Victor Eremeev prof. dr hab.
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Paweł Możejko dr hab.
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Leszek Ziemczonek dr
PeopleUniversity education 1973-1978 – Nicolaus Copernicus University in Toruń, University of Gdańsk in Gdańsk, Mathematical Physics, M. Sc. 1979 – Diploma of Postgraduate Studies, Pedagogics 1989 – Institute of Physics, Polish Academy of Sciences in Warsaw, Theoretical Physics, Ph. D. 2010-2012 – Diploma of Postgraduate Studies, Mathematics Training: · 09.1983 – Trieste (Italy) – International Centre for Theoretical Physics...
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Justyna Szostak dr inż.
PeopleI Gdańsk University of Technology: Chair of the Rector’s Internationalization Committee (October 2020 - Present) Erasmus + Coordinator for students and staff members, Faculty of Applied Physics and Mathematics (Mar 2017 - Present) Dean's Proxy for Internationalization, Faculty of Applied Physics and Mathematics (October 2020 - Present) Coordinator of the International Relations Office of the Faculty of Applied Physics and...
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Joanna Raczek dr inż.
PeopleEmployment 2003 -- 2019: Faculty of Applied Physics and Mathematics, Gdańsk University of Technology. 2019 - present: Faculty of Electronic, Informatics and Telecominications, Gdańsk University of Technology. Education May 2007: Doctor of Philosophy in Mathematics, University of Gdańsk. Doctoral dissertation: "Paired domination and doubly domination in graphs". Supervisor: dr hab. Jerzy Topp. 2000 -- 2004 Bachelor of Science...
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Aleksandra Dorota Mielewczyk-Gryń dr hab. inż.
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Preface
PublicationThis special issue of Discussiones Mathematice Graph Theory (DMGT) is dedicated to selected papers presented at the 13th Workshop on Graph Theory: Colourings, Independence and Domination (CID) held on 18-23 September 2009 in Szklarska Poręba, Poland. It continues a series of international workshops: 1993-1997 in Lubiatów, 1998-2001 in Gronów, and 2003-2007 in Karpacz. The meeting was organized by the Faculty of Mathematics, Computer...
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Mieczysław Brdyś prof. dr hab. inż.
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Beata Bochentyn dr hab. inż.
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Grzegorz Graff prof. dr hab.
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Unifying Aspects of Generalized Calculus
PublicationNon-Newtonian calculus naturally unifies various ideas that have occurred over the years in the field of generalized thermostatistics, or in the borderland between classical and quantum information theory. The formalism, being very general, is as simple as the calculus we know from undergraduate courses of mathematics. Its theoretical potential is huge, and yet it remains unknown or unappreciated.
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Joanna Janczewska prof. dr hab.
PeopleJoanna Janczewska obtained her PhD degree at the University of Gdansk in 2002. From October 1999 to September 2004 she was an assistant at the University of Gdansk. Since October 2004 she has been an assistant professor at the Gdansk University of Technology. Moreover, from October 2008 to September 2010 she had a visiting position in the Institute of Mathematics of the Polish Academy of Sciences. Her mathematical interests...
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Anna Niewulis dr
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Jan Kozicki dr hab. inż. arch.
PeopleIn year 2002 after obtaining master's degree in construction was employed on Faculty of Civil and Environmental Engineering. In 2004 obtained master's degree in architecture on Faculty of Architecture focusing on a research outpost on Mars. Defended PhD in year 2007 in the field of numerical modeling. In 2013 obtained Licentiate degree in theoretical physics on University of Gdańsk. In year 2014 obtained habilitation in technical...
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Topology and Dynamical Systems in Action - Summer school 2023
e-Learning CoursesThe course is designed for participants in the Spinnaker summer school in mathematics.
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Radosław Szmytkowski prof. dr hab.
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