2013 - Repozytorium publikacji - Politechnika Gdańska

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AC motor feeding cable consequences on EMC performance of ASD
- Jarosław Łuszcz
2013
High level of conducted EMI emissions of adjustable speed drives (ASD) is one of the most difficult problems in contemporary applications. Many investigations are carried out in order to find more effective methods allowing to predict this emission at early stage of design, and therefore to predict adequate countermeasures. This paper deals with the method which allows to estimate by simulation the influence of motor feeding cable parameters on overall EMC performance of ASD. Proposed method is based on analysis of common mode (CM) impedance of motor feeding cable and motor windings which allows to determine their broadband model parameters. Motor windings are modelled by ladder circuit with an adequate number of rungs and motor feeding cable by lossy transmission line. After experimental verification of selected impedances of the evaluated model it can be successfully used for calculation of CM currents distribution at output side of frequency converter for various motor feeding cable lengths. Influence of motor feeding cable parameters on CM currents emission can be evaluated using this model, especially the cable length which depends on particular application requirements and can be determined only at ASD installation design stage.
Accuracy of Differential Phase Delay Estimation for GPS Spoofing Detection
- Jarosław Magiera
- Ryszard Katulski
2013
GPS spoofing is an attack based on transmission of false signals to target receivers, in order to force the computation of incorrect time, position or velocity information. It is a threat which is recently considered with continuously growing awareness. There is a need for effective way of GPS spoofing detection. Many groups of methods are proposed in the literature. Spatial processing methods are considered to be robust in a wide range of scenarios and may fail only when a very sophisticated device is used for spoofing. In this article, a spoofing detection method, based on phase delay measurements, is proposed. Accuracy and precision of phase delay estimation is assessed for various qualities of received signal. Spoofing detection thresholds are determined. Efficiency of this method is evaluated in terms of probability of false alarm and probability of detection.
Accuracy of the Discrete Green's Function Formulation of the FDTD Method
- Tomasz Stefański
2013 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
This paper reports an evaluation of the accuracy of the discrete Greens function (DGF) formulation of the finite-difference time-domain (FDTD) method. Recently, the closed-form expression for the DGF and its efficient numerical implementation were presented, which facilitates applications of the DGF in FDTD simulations of radiation and scattering problems. So far, the accuracy of the DGF formulation of the FDTD method has been rather marginally treated in the literature. Moreover, although windowing has been reported as an efficient method of DGF waveform truncation and a remedy for stability issues, the accuracy and usability of this technique has not yet been fully evaluated. In this paper, previously unrevealed accuracy limitations of the DGF formulation of the FDTD method are demonstrated in several numerical tests. Specifically, the truncation errors are compared for the most frequently applied windowing functions, with the best performance shown for the Hann's window.
Accurate modeling of quasi-resonant inverter fed IM drive
- Piotr Musznicki
- Marek Turzyński
- Piotr Chrzan
2013
In this paper wide-band modeling methodology of a parallel quasi-resonant dc link inverter (PQRDCLI) fed induction machine (IM) is presented. The modeling objective is early-design stage prediction of conductive electromagnetic interference (EMI) emissions of the considered converter fed IM drive system. Operation principles of the selected topology of PQRDCLI feeding IM drive are given. Modeling of the converter drive system is based on the partial-element equivalent circuit (PEEC) method. Component elements description with parasitic inductive and capacitive couplings and distribution of current flow trough connections (skin effects) and cables are included. Simulation study is carried out in the Saber/MAST programming environment with the aid of especially developed Matlab tool, enabling the PEEC matrix equations to be converted directly to the Saber@Sketch macrocomponents. Results of modeling and simulation are experimentally validated.
Acoustic field and the entropy mode induced by it in a waveguide filled with some non-equilibrium gases
- Anna Perelomova
2013 Pełny tekst CENTRAL EUROPEAN JOURNAL OF PHYSICS
The non-linear propagation of an acoustic beam in a rectangular waveguide is considered. The medium of sound propagation, is a gas where thermodynamically non-equilibrium processes take place: such as exothermic chemical reactions or excitation of vibrational degrees of a molecule’s freedom. The incident and reflected compounds of the acoustic field do not interact in the leading order in the case of periodic weakly nonlinear sound with zero mean value of velocity. The acoustic heating or cooling in a waveguide is discussed.
Acoustic Processor of the MCM Sonar
- Mariusz Rudnicki
- Jan Schmidt
- Aleksander Schmidt
- Wojciech Leśniak
2013 Pełny tekst Automatyka / Automatics
This paper presents the concept of an acoustic processor of the mine countermeasure sonar. Developed at the Department of Marine Electronics Systems, Gdansk University of Technology, the acoustic processor is an element of the MG-89, a modernised underwater acoustic station. The focus of the article is on the modules of the processor. They are responsible for sampling analogue signals and implementing the algorithms controlling the measurement cycle and digital signal processing. As it performs the above functions, the device should be highly reliable and resistant to mechanical and weather conditions and ensure a user friendly operation. The functions of the processor software should help with object detection and classification. In addition to these properties, the acoustic processor should operate in real time. The results of measurements should be displayed with the shortest possible delay in relation to sounding signals to allow the operator to take decisions quickly and establish if the object poses a risk. This acoustic processor meets all of the above requirements.
Acoustics - new services for urban planning, research and education
- Józef Kotus
- Maciej Szczodrak
- Bożena Kostek
- Andrzej Czyżewski
2013
The main purpose of the presented design is twofold, namely: providing detailed information about the noise threats that occur every day in city areas and preventing the noise induced hearing loss especially among young people. An experimental system designed for the continuous monitoring of the acoustic climate of urban areas was developed and implemented within the PLGrid Plus project. The assessment of environmental threats is performed based on online data, acquired through a grid of engineered monitoring stations, employing some selected psychoacoustic properties of the human hearing system. Another aim is to make available efficient computational tools for the community of acousticians engaged in the noise threat combating.
Adaptacja osadu do wód poosadowych i zewnętrznego źródła węgla.
- Joanna Majtacz
- Magdalena Kaszubowska
2013 Zeszyty Naukowe Politechniki Gdańskiej. Inżynieria Lądowa i Wodna
Spełnienie obowiązujących obecnie warunków usuwania azotu, możliwe jest w przypadku osią-gnięcia wysokiej efektywności procesu denitryfikacji, która musi być poprzedzona pełną nitryfikacją, wiąże się to z wysokimi kosztami napowietrzania w bioreaktorach. Do stref anoksycznych konieczne jest dostarczenie odpowiedniej ilości węgla organicznego, co wiąże się z koniecznością wspomagania denitryfikacji. Odcieki z beztlenowych procesów przeróbki osadu w komorach fermentacji (tzw. wody posadowe) są podstawowym źródłem azotu dopływającego do części biologicznej komunalnych oczyszczalni ścieków. Wody poosadowe mogą odprowadzać od 10-30 % całkowitego ładunku azotu zawartego w dopływie do oczyszczani. Wydzielone systemy oczyszczania wód posadowych znacząco redukują ładunek azotu kierowany do głównego reaktora i poprawiają ogólny efekt usuwania azotu. Celem badań kinetycznych jest ocena przydatności produktów odpadowych z produkcji alkoholu do intensyfikacji procesu biologicznej denitryfikacji, w trakcie oczyszczania odcieków z przeróbki osadu w komunalnych oczyszczalniach ścieków opartych na metodzie osadu czynnego. W części doświadczalnej wykonano eksperymenty adaptacji osadu czynnego do wód osadowych i wpływu zewnętrznego źródła węgla (etanolu i olejów fuzlowych) na przebieg denitryfikacji. Podczas adaptacji osadu do wód poosadowych, zauważono znaczną poprawę efektywności denitryfikacji zarówno w reaktorze z konwencjonalnym źródłem węgla – etanolem, jak i alternatywnym –olejem fuzlowym. W końcowym etapie badań stężenia azotu amonowego i azotynów utrzymywały się stabilnie na poziomie poniżej 2 g N/m3, a efektywność usuwania azotu wynosiła ponad 90%.
Adaptive Method of Adjusting Flowgraph for Route Reconstruction in Video Surveillance Systems
- Andrzej Czyżewski
- Karol Lisowski
2013 FUNDAMENTA INFORMATICAE
Pawlak’s ﬂowgraph has been applied as a suitable data structure for description and anal- ysis of human behaviour in the area supervised with multicamera video surveillance system. Infor- mation contained in the ﬂowgraph can be easily used to predict consecutive movements of a partic- ular object. Moreover, utilization of the ﬂowgraph can support reconstructing object route from the past video images. However, such a ﬂowgraph with its accumulative nature needs a certain period of time for adaptation to changes in behaviour of objects which can be caused, e.g. by closing a door or placing other obstacle forcing people to pass it by. In this paper a method for reduction of time needed for ﬂowgraph adaptation is presented. Additionally, distance measure between ﬂowgraphs is also introduced in order to determine if carrying out the adaptation process is needed.
Adhesion of organic coatings to hot-dip galvanized steel
- Andrzej Miszczyk
2013 Ochrona przed Korozją
Duplex systems provide long-time corrosion protection, much longer than the sum of the lifetimes of zinc and paint used individually. However loss of adhesion between coating and zinc substrate is often found in practice. Different methods of zinc surface preparations are used in the fi eld. The aim of this study was to examine and compare coating protection when the old zinc surface, stored during long-time period (15 years) in laboratory conditions, was painted. Adhesion and impedance studies using epoxy coating systems on galvanized steel substrate, which had been prepared by different methods, were performed.
Adjusting Game Difficulty by Recreating Behavioral Trees of Human Player Actions
- Waldemar Korłub
- Michał Wójcik
2013
This paper presents a proposition of a method for adjusting game difficulty to the current level of player's skills in one-on-one games. The method is based on recognition of human player's actions and recording of those actions in the form of behavioral trees. Such trees are later used to drive behaviors of computer-controlled opponents so that human player has beat hit own strategy and improve on it, to win subsequent games. The basic concept of the method is presented on the simple example of Tic-tac-toe. The paper discusses required enhancements and modifications needed for the use of this method in more refined games. Finally, additional aspects of modern games related to the application of presented method, e.g. continuity of game universe (in contrast to discrete board games) and vague and hard to recognize player's actions, are brought into consideration.
ADT in mammography
- Mariusz Kaczmarek
- Mateusz Moderhak
- Antoni Zbigniew Nowakowski
2013
We discuss limitations of the known methods of IR imaging in diagnostics of breast cancer. In conclusion we show that for practical reasons one requires new approaches because the known methods based on simple observation of external temperature distribution are not fully effective. Even advanced pattern recognition could not help too much for static images. We ask the question: may active dynamic thermography, known in nondestructive testing of materials, be of any help? Analysis of thermal transients forced by external thermal excitation shows even on simple models, that one may expect visible improvement in resolution after such excitation. Applied models allow analysis of both, static as well as active thermograms. Basing on the models one may recognize elements of the internal structure of a breast not visible using static pictures. This new in clinical practice method seems to be promising, but still needs more studies.
AEGIS — demonstrator technologii C-IED
- Sławomir Ambroziak
- Ryszard Katulski
- Jarosław Sadowski
- Jacek Stefański
2013 Zeszyty Naukowe Akademii Marynarki Wojennej
W artykule przedstawiono budowę i działanie opracowanego na Politechnice Gdańskiej demonstratora technologicznego systemu AEGIS, przeznaczonego do przeciwdziałania atakom z wykorzystaniem prowizorycznych urządzeń wybuchowych detonowanych drogą radiową (RCIED — Radio Controlled Improvised Explosive Devices). Przedstawiono zaimplementowaną oryginalną metodę generowania sygnału zagłuszającego o dowolnie ukształtowanym widmie częstotliwościowym, będącą przedmiotem zgłoszenia patentowego o numerze P.398050.
Affect-awareness framework for intelligent tutoring systems
- Agnieszka Landowska
2013
The paper proposes a framework for construction of Intelligent Tutoring Systems (ITS), that take into consideration student emotional states and make affective interventions. The paper provides definitions of `affect-aware systems' and `affective interventions' and describes the concept of the affect-awareness framework. The proposed framework separates emotion recognition from its definition, processing and making decisions on interventions. The components of the proposed framework were described, including trustworthiness model and affect-aware control mechanisms, and a case study of the proposed framework implementation in GERDA Intelligent Tutoring System was also presented. Presented evidence allows to state, that affect-awareness framework allows to reduce the risk of unnecessary and disturbing application intervention and improves application adaptability and trustworthiness.
Affective computing and affective learning – methods, tools and prospects
- Agnieszka Landowska
2013 Pełny tekst EduAkcja. Magazyn Edukacji Elektronicznej
Every teacher knows that interest, active participation and motivation are important factors in the learning process. At the same time e-learning environments almost always address only the cognitive aspects of education. This paper provides a brief review of methods used for affect recognition, representation and processing as well as investigates how these methods may be used to address affective aspect of e-education. The paper analyzes on how affective learning and affective computing can be combined to assess and improve effectiveness of educational processes, including the processes enhanced with technology. Three case studies are analyzed to illustrate the complexity and diversity of affective learning tools. Some of the challenges of affective computing are outlined and prospects of application in e-learning are discussed.
Agents in Simulation of Cyberattacks to Evaluate Security of Critical Infrastructures
- Rafał Leszczyna
2013
In the last years critical infrastructures have become highly dependent on the information technologies and exposed to cyberattacks. Because the effects of the attacks can be detrimental, it is crucial to comprehensively asses the security of the infrastructures' information systems. This chapter describes MAlSim - the simulator of malicious software based on software agents, developed for the needs of a testbed for critical infrastructures security. The authors explain the choice of agent paradigm for the development of the toolkit, present main design decisions, overview changes to the project introduced during the implementation, and provide the details of the completed project followed by a brief description of the application of MAlSim to security evaluation of a power plant. The chapter concludes with the discussion of the perspectives for the future of agent technology based on the experiences which came during the course of the project.
Aggregation of nonionic surfactants in imidazolium ionic liquids
- Anna Selwent
- Justyna Łuczak
2013
Micellar aggregation of surfactants in aqueous solutions has been described in terms of the balance between dispersive interactions of the hydrocarbon part of the amphiphilic molecule, and the hydration and electrostatic repulsive effects of hydrophilic head group. Changing the interactions by replacing water with another polar solvent, such as amides or glycols, has been studied to a smaller extent (Singh, Saleem et al. 1980; Li, Zhang et al. 2005). To this date, only little number of known non-aqueous polar solvents was found to support micelle formation. As a consequence, changing properties of a self-assembly system is limited manly to modification of the amphiphile structure. Despite extensive studies conducted on self-assembly in typical non-aqueous solvents (and their mixtures), the process is still not fully understood (Greaves and Drummond 2008).
Air Pollution: Monitoring
- Waldemar Wardencki
2013
The entry presents an overview of the issues in the field of air pollution monitoring. At the beginning, the general objectives of air monitoring, ambient air quality standards for so-called criteria pollutants, and their sources are discussed. In the next part, both analytical methods and instruments for monitoring of ambient air and stack gases are briefly presented. Additionally, other approaches used in air pollution monitoring, such as biomonitoring, geographical information system (GIS), or remote monitoring, are also briefly characterized.
Aktualny stan prawny w zakresie reklam widzianych z drogi i rekomendacje do zmian
- Kazimierz Jamroz
2013 Pełny tekst Transport Miejski i Regionalny
W artykule zostały omówione regulacje składające się na aktualny stan prawny dotyczący umiejscawiania reklam widzianych z drogi. Obowiązujące przepisy prawa nie zawierają wyczerpującej regulacji na temat umiejscawiania reklam w kontekście brd, przez co interesy użytkowników dróg nie są należycie chronione. Uwagi nt. obowiązujących norm uzupełnione zostały o przegląd wybranych orzeczeń sądów administracyjnych oraz przedstawienie propozycji zmian aktualnego stanu prawnego również w kontekście projektowanych przepisów wzmacniających instrumenty ochrony krajobrazu.
Akwarela- pasje i namiętności
- Jacek Krenz
2013
Monografia dwujęzyczna: w języku polskim i angielskim przedstawiająca twórczość akwarelistów, członków założycieli nowo powstałego Stowarzyszenie Akwarelistów Polskich.