Repozytorium publikacji - Politechnika Gdańska

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Repozytorium publikacji
Politechniki Gdańskiej

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Publikacje z roku 2011

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  • Selected problems of determining the course of railway routes by use of GPS network solution
    • Władysław Koc
    • Cezary Specht
    2011 Pełny tekst Archives of Transport

    W 2009 roku Politechnika Gdańska rozpoczęła prace nad wykorzystaniem ciągłych pomiarów pozycji systemów geodezji satelitarnej dla wyznaczania przebiegu trasy kolejowej z wykorzystaniem fazowych metod GPS opartych o serwis NAVGEO polskiej Aktywnej Sieci Geodezyjnej ASG-EUPOS. W celu eliminacji błędów przypadkowych wpływających na dokładność wyznaczenia trasy kolejowej w następnym roku zespół przeprowadził dwie kampanie pomiarowe Port wykorzystując 3 odbiorniki Leica GPS system 1200 umieszczone w osi platformy pomiarowej. Uzyskiwanie możliwie najwyższych dokładności zapewniono poprzez optymalizację czasu pomiaru minimalizując wartość współczynników DOP i maksymalizując liczbę satelitów. Artykuł prezentuje wybrane aspekty badań i wyników dotychczas realizowanych kampanii. Poddano w nim dyskusji możliwości uzyskiwania centymetrowych dokładności wyznaczenia położenia; rezultaty pomiarów zastosowano w procesie projektowania tras kolejowych.

  • Selected Propagation Models Modification for Application in Container Terminal
    • Sławomir Ambroziak
    • Ryszard Katulski
    2011

    It is particularly important to look for any propagation model that could be useful for designing mobile radio systems in container terminal environment. The selected propagation models have been investigated. The applied research methodology has been described too. Results of the statistical adjustment in terms of signal loss determination in such environment have been analysed. The analysis have proved effectiveness of adjustment by increasing the accuracy of path loss estimation.

  • Selective Protection for All-Optical Physical Impairment Constrained Routing
    • Peter Soproni
    • Tibor Cinkler
    • Jacek Rak
    2011

    W przypadku sieci optycznych, zauważalna jest obecnie tendencja dążenia do transmisji całowicie optycznej (tz. bez konwersji O/E/O w węzłach tranzytowych). Jednakże w niedalekiej przyszłości, z uwagi na techniczne ograniczenia, niemożliwa będzie obsługa całości ruchu wyłącznie w dziedzinie optycznej. Operatorzy będą więc zainteresowani oferowaniem rozwiązań przejściowych implikujących przełączanie w dziedzinie optycznej jedynie niewielkiej części ruchu. W niniejszym artykule zaproponowane zostały metody doboru tras przeżywalnych, które pomogą operatorom powiększyć zysk w obliczu stosowania rozwiązań przejściowych.

  • Selekcja i ekstrakcja cech
    • Agata Kołakowska
    2011

    W rozdziale omówiono sposób przedstawiania danych w postaci wektorów cech, które stanowią zbiory uczące np. w zadaniach klasyfikacji lub grupowania. Opisano metody generowania podzbiorów cech (metodę podziału i ograniczeń, metody sekwencyjne) oraz oceny jakości tych podzbiorów. Zaprezentowano wybrane algorytmy ekstrakcji cech (analizę głównych składowych, wielowymiarowe skalowanie, liniową analizę dyskryminacyjną).

  • Self-assemblies of novel magnesium porphyrins mimicking natural chlorosomal bacteriochlorophylls
    • Jędrzej Szmytkowski
    • Jonas Conradt
    • Hendrik Kuhn
    • Chilla Malla Reddy
    • Mihaela Carmen Balaban
    • Teodor Silviu Balaban
    • Heinz Kalt
    2011 Journal of Physical Chemistry C

    Self-assembling porphyrins are promising materials to mimic natural bacteriochlorophylls c, d, or e encountered in the chlorosomes of photosynthetic bacteria. We have studied four novel magnesium porphyrins mimicking this chlorosomal antenna system. In contrast to previous articles reporting synthetic Zn-porphyrins, our studies focus on porphyrins with Mg as the central atom, which mimic more closely the natural bacteriochlorophylls. The analysis of time-resolved photoluminescence dynamics based on the decay-associated emission spectra shows a short-lived component associated with the supramolecular architecture. It confirms the ordered nature of the investigated porphyrins and suggests that these self-assemblies can be used as artificial antennae in light-harvesting devices like biomimetic solar cells.

  • Self-optimizing narrowband interference canceller - can reference signal help?
    • Maciej Niedźwiecki
    • Michał Meller
    2011

    SONIC (Self-Optimizing Narrowband Interference Canceller) is an acronym of the recently proposed active noise control algorithm with interesting adaptivity and robustness properties. SONIC is a purely feedback controller, capable of rejecting nonstationary sinusoidal disturbances (with time-varying amplitudes and/or frequencies) in the presence of plant (secondary path) uncertainties. We show that even though SONIC can work reliably without access to the reference signal, when frequency of the disturbance is unknown and possibly time-varying the algorithm can take advantage of such an additional source of information. Unlike the classical feedforward solutions, the reference signal is used only to extract information about the instantaneous frequency of the disturbance. The time advantage, available due to the fact that the acoustic delay in the system is larger than the electrical delay, allows one to incorporate in the control loop the smoothed, and hence more accurate, frequency estimates. This increases the attenuation efficiency of SONIC and widens its operating range - the modified algorithm can be safelyused in the presence of faster frequency changes.

  • Self-Organizing Map representation for clustering Wikipedia search results
    • Julian Szymański
    2011 LECTURE NOTES IN COMPUTER SCIENCE

    The article presents an approach to automated organization of textual data. The experiments have been performed on selected sub-set of Wikipedia. The Vector Space Model representation based on terms has been used to build groups of similar articles extracted from Kohonen Self-Organizing Maps with DBSCAN clustering. To warrant efficiency of the data processing, we performed linear dimensionality reduction of raw data using Principal Component Analysis. We introduce hierarchical organization of the categorized articles changing the granularity of SOM network. The categorization method has been used in implementation of the system that clusters results of keyword-based search in Polish Wikipedia.

  • Self–Organizing Map representation for clustering Wikipedia search results
    • Julian Szymański
    2011

    The article presents an approach to automated organization of textual data. The experiments have been performed on selected sub-set of Wikipedia. The Vector Space Model representation based on terms has been used to build groups of similar articles extracted from Kohonen Self-Organizing Maps with DBSCAN clustering. To warrant efficiency of the data processing, we performed linear dimensionality reduction of raw data using Principal Component Analysis. We introduce hierarchical organization of the categorized articles changing the granularity of SOM network. The categorization method has been used in implementation of the system that clusters results of keyword-based search in Polish Wikipedia.

  • Semantic Integration of Heterogeneous Recognition Systems
    • Paweł Kaczmarek
    • Piotr Raszkowski
    2011 LECTURE NOTES IN COMPUTER SCIENCE

    Computer perception of real-life situations is performed using a variety of recognition techniques, including video-based computer vision, biometric systems, RFID devices and others. The proliferation of recognition modules enables development of complex systems by integration of existing components, analogously to the Service Oriented Architecture technology. In the paper, we propose a method that enables integration of information from existing modules to calculate results that are more accurate and complete. The method uses semantic description of concepts and reasoning to manage syntactic differences between information returned by modules. The semantic description is based on existing real-world concepts in video recognition and ubiquitous systems. We propose helper functionalities such as: module credibility rating, confidence level declaration and selection of communication protocol. Two integration modes are defined: voting of matching concepts and aggregation of complementing concepts.

  • Semantyczny portal wiedzy środowiskiem wsparcia procesów integracji uczelni i biznesu
    • Irena Bach-Dąbrowska
    • Łukasz Szczygielski
    2011

  • Semi-adaptive feedback active control of MRI noise
    • Michał Meller
    • Maciej Niedźwiecki
    • Tetsu Hirofumi
    • Kajikawa Yoshinobu
    2011

    A feedback controller is proposed for cancellation of magnetic resonance imaging (MRI) noise. The design of the controller takes into account specific features of the MRI noise signal. Simulation results show that a considerable rejection rate of the MRI noise can be obtained.

  • Sensitivity to nitrogen dioxide of electrocatalytic gas sensor based on NASICON
    • Anna Strzelczyk
    2011

    W pracy przedstawiono wyniki badań czujnika elektrokatalitycznego na bazie NASICONu.

  • Sensorless IPMSM drive with rotor position estimator based on analysis of phase current derivatives
    • Leszek Jarzębowicz
    2011

    This paper describes a sensorless Interior Permanent Magnet Synchronous Motor (IPMSM) drive designed for traction applications. Wide-speed sensorless operation is provided with the use of three methods of rotor position estimation designed for: a standstill, low- and high-speed range. The paper focuses on the high-speed estimation algorithm. The estimator uses the derivatives of motor phase currentsresulting from PWM modulation to obtain the rotor position. The algorithm is characterized by very simple formulae. The calculation of the rotor position is performed in every PWM cycle. However, the determination of phase current derivatives requires a special current measurement algorithm in which sampling is coordinated with inverter transistors switching. The basis of the algorithm is presented, accompanied by an error analysis. The current sampling issues are reviewed and the laboratory test results are given and discussed.

  • Service time distribution influence on end-to-end call setup delay calculation in networks with Session Initiation Protocol
    • Piotr Gutkowski
    • Sylwester Kaczmarek
    2011

    The most important GoS parameter for networks with SIP protocol is end-to-end call setup delay. So far there were no coherent models allowing calculation of these parameters for networks with SIP protocol. Few models were developed but they are insufficient. In the paper we propose model which allows end-to-end call setup delay calculation for networks with SIP protocol. The model is using chain of M/G/1/K models and is applicable for network with any number of the links. There are two versions of calculation depending on service time distribution type. In basic form the model bases on deterministic service time distribution and equations for M/G/1/K were taken directly from the literature. In more sophisticated version, for uniform distribution of service time, equations were derived by the authors. The paper includes results of call setup delay calculation obtained using each distribution type. They show that there is no big difference when applying model with deterministic service time than using model with uniform distribution service time (for all checked scenarios the difference was below 3%). The results were verified by simulation.

  • Shaking table experimental study on damage mechanism of the disconnecting switch under seismic excitation
    • Paweł Dembowski
    • Robert Jankowski
    2011 Key Engineering Materials

    The efficiency of the energetic network is a very import safety issue in the region experienced by the earthquake. High voltage disconnecting switches are important elements of the energetic infrastructure used to separate electric circuits (i.e. during repairs), which should not be damaged remaining fully operational. The aim of the paper is to show the results of the shaking table experimental investigation focused on damage mechanism of a high voltage disconnecting switch under seismic excitation. The real example of the two-column pantograph-type disconnecting switch was considered in the study. First, the tests were carried out by exciting the unit with the sweep-sine function. Based on the results, the structural dynamic properties of undamaged structure (natural frequencies, damping ratios) could be determined. Then, the so called rumbling seismic tests were conducted in order to determine the seismic strength of disconnecting switch according to the standards PN-EN 60068-3-3. After each experiment, the sweep-sine test was carried out so as to check the decrease in the natural frequencies of the unit. The results of the study show that the lower parts of the columns, which serve as isolators, are the most critical locations of the disconnecting switch considered. The unit was damaged due to failure of one of the rotational mechanisms installed at the bottom of columns.

  • Shannon Capacity and Ramsey Numbers
    • Marcin Jurkiewicz
    • Marek Kubale
    2011

    Ramsey-type theorems are strongly related to some results from information theory. In this paper we present these relations.

  • Shipping Low Frequency Noise and Its Propagation in Shallow Water
    • Eugeniusz Kozaczka
    • Grażyna Grelowska
    2011 Pełny tekst ACTA PHYSICA POLONICA A

    One of the most significant factor influencing acoustical climate of the sea is underwater noise generated by moving ships. If the considered sea area has features of the shallow water, namely the wave frequency fulfils relation f < 10c/h, where c denotes phase speed of sound, and h is depths of the sea, then in certain distance from the wave source specific image of sound pressure distribution in the mean of wave modes appears. The modes constitute wave packet propagating with group speed in the direction parallel to the sea surface. The paper presents results of the experimental investigation concerning the distribution of the sound field created by moving ship in the shallow water, in a small distance from the ship. The main acoustical characteristics, describing features of the field are spectrograms in pseudo-3D system: distance and frequency in geometrical form, and sound intensity in the optical one (color). Results presented in such a way pointed individual features of the sound source known often as acoustical signature of the source (ship).

  • Siedem i pół wieku Wrzeszcza
    • Jakub Szczepański
    2011

    Syntetyczna historia rozwoju przestrzennego dzielnicy Wrzeszcz.

  • Silent Sonar with matched filtration
    • Roman Salamon
    • Jacek Marszal
    • Jan Schmidt
    • Mariusz Rudnicki
    2011 Pełny tekst HYDROACOUSTICS

    Radars with continuous wave frequency (CW FM sonars) are used in radiolocation as 'silent sonars'. They determine the distance to target by measuring the difference between the frequency of the sounding signal and echo signal. The article presents the principle of operation and parameters of silent CW FM sonars. Target distance determined by these sonars is based on the signal at the output of the matched filter. The Doppler effect is studied in detail to identify its effect on the sonar's parameters. The results of theoretical calculations are presented together with the results of the sonar's computer simulation.

  • Silniki piezoelektryczne o ruchu prostym i złożonym - przegląd wybranych topologii i sterowania ruchem
    • Roland Ryndzionek
    • Łukasz Sienkiewicz
    • Wojciech Szłabowicz
    • Marek Grzywacz
    • Mieczysław Ronkowski
    2011 Wiadomości Elektrotechniczne

    W artykule omówiono topologię i sterowanie silników o ruchu prostym i złożonym. Prace nad tymi silnikami są kontynuowane w wielu ośrodkach, zwłaszcza w Japonii, USA, Niemczech oraz Francji. Silniki piezoelektryczne/ultrasoniczne dzięki swym wyjątkowym cechom - uproszczonej strukturze elektromechanicznej (możliwości wykonania bez wału), bezszumnej pracy, samohamowności, precyzyjnemu zatrzymywaniu się dla zadanego położenia, bardzo małej elektromechanicznej stałej czasowej, a głównie dzięki bardzo dużej gęstości momentu obrotowego, znalazły zastosowanie jako elementy wykonawcze - aktuatory, szczególnie w napędach o ruchu złożonym - stosowanych w aeronautyce.