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Gdańsk University of Technology

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Publications from the year 2015

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  • Evaluation of position estimation based on accelerometer data
    • Zdzisław Kowalczuk
    • Tomasz Merta
    2015

    The paper concerns the problem of integrating data from accelerometers. A suitable model of a MEMS accelerometer is presented which is a part of inertial measurement units (IMU). Such units allow to measure orientation as well as to localize systems. They also appear to be applicable for systems positioning. The main purpose of the paper is to discuss conditions that must be satisfied to calculate the location of the sensor by means of the double integration of acceleration. The model takes into account static and dynamic settings as well as the features of low-cost MEMS accelerometers. Much attention is devoted to the impact the practical motion signals from the sensor have on the desired output of integration, and simulation results emphasize the problem of determining the 'true' linear acceleration from accelerometer measurements.

  • Evaluation of Selected Innovation Policy Instruments on the Example of Poland
    • Anna Lis
    • Ewa Romanowska
    2015 Procedia - Social and Behavioral Sciences

    The main purpose of the paper is to analyze and evaluate the selected instruments of innovation policy in Poland: cooperative relations, business environment institutions and innovation centers, supported within Priority Axis V of OP IE 2007-2013. The evaluation was made on the basis of the four criteria: complementarity, adapting to the needs of businesses, the impact on the innovation and durability of the provided support. The study was conducted from the perspective of institutions providing support as well as companies benefiting from this support. The results of the study indicate relatively high complementarity of the applied instruments. The differences were evident in terms of adapting them to the needs of entrepreneurs and their impact on innovations, taking into account also a longer period of time. The best results were achieved with regard to the innovation centers, while the other instruments featured weaknesses that reduce the expected results of the provided support

  • Evaluation of the impact of geometry and plastic deformation on the stray magnetic field around the bone shaped sample
    • Zbigniew Usarek
    • Bolesław Augustyniak
    2015 INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS

    Influence of two factors: the variable cross-section and the localized plastic deformation, which affect the stray magnetic field profile of a ferromagnetic sample have been studied. Evaluation of an effect size is based on the analysis of the stray magnetic field component which is tangential to the longest dimension of a sample. However, in order to describe the nature of the stray magnetic field, the normal component (perpendicular to the tangential one and to the largest surface of a sample) was also measured.It was found that the impact of the localized plastic deformation is qualitatively similar to the impact of the geometric narrowing. For the assessment one used a comparison of so called k coefficient that was determined as the absolute value of the derivative of the tangential component. Although some authors treat its distribution as information about residual stess distribution, the results indicate that a characteristic curve with two maxima stems from a cross-section reduction as well as plastic deformation presence.

  • EVALUATION OF THE SEMIVARIOGRAM SELECTION ON THE KRIGING INTERPOLATION
    • Wioleta Błaszczak-bąk
    • Katarzyna Pajak
    • Anna Sobieraj-Żłobińska
    2015

    The aim of the paper is to present the possibilities of geostatistical interpolation kriging method using in the process of generating digital terrain models (DTM). The source of data is a direct measurements realized with a precision GNSS positioning kinematic measurement technique RTN. Kriging algorithm was analysed, especially in the meaning of a semivariogram every step. Theoretical semivariogram selection influence on the interpolation accuracy was verified, and thus, the accuracy of the resulting terrain model. Moreover, phenomenon as drift and anisotropy were tested and their influence on the result. The size of the effect was determined with two parameters: the kriging variance and root-mean-square error (RMS). The research results let the authors conclude that proper interpolation by kriging algorithm is a very complicated process and should be based on a geostatistical knowledge. By a right interpolation with the kriging, an accurate surface model can be gained which can reveal every single morphology details.

  • Evaluation of time-efficiency of disjoint paths calculation schemes
    • Kanstantsin Myslitski
    • Jacek Rak
    2015

    The concept of alternate paths has been shown in the literature to provide fast response of a network to failures of its elements (nodes/links) affecting flows along the primary communication paths. Various approaches have been proposed to reduce the time necessary to redirect the respective flows onto the alternate paths. In this paper, we focus on another important objective, that so far has not received much attention, i.e., reduction of the overall time needed to calculate the set of working and alternate paths. The issue is important e.g., in the case of reactive approaches to survivable routing (if a failure of a network element leads to multiple attempts to determine the respective alternate paths), or when performing the periodic updates of the resilient routing scheme in the global scale. The aim of this paper is to present the analysis of time efficiency of our approach to provide the global set of end-to-end disjoint paths in comparison to the reference Bhandari's scheme. In particular, after describing the respective examples of our algorithm execution, we show (based on simulations) that it is possible to establish the sets of primary and alternate paths up to 70 times faster, compared to the common existing reference schemes.

  • Evidence for consolidation of neuronal assemblies after seizures in humans
    • Mark R. Bower
    • Matt Stead
    • Regina S. Bower
    • Michał Tomasz Kucewicz
    • Vladimir Sulc
    • Jan Cymbalnik
    • Benjamin H. Brinkmann
    • Vincent Vasoli
    • Erik K. ST.Louis
    • Frederic Meyer
    • W. Richard Marsh
    • Gregory A. Worrell
    2015 Full text Journal of Neuroscience

    The establishment of memories involves reactivation of waking neuronal activity patterns and strengthening of associated neural circuits during slow-wave sleep (SWS), a process known as "cellular consolidation" (Dudai and Morris, 2013). Reactivation of neural activity patterns during waking behaviors that occurs on a timescale of seconds to minutes is thought to constitute memory recall (O'Keefe and Nadel, 1978), whereas consolidation of memory traces may be revealed and served by correlated firing (reactivation) that appears during sleep under conditions suitable for synaptic modification (Buhry et al., 2011). Although reactivation has been observed in human neuronal recordings (Gelbard-Sagiv et al., 2008; Miller et al., 2013), reactivation during sleep has not, likely because data are difficult to obtain and the effect is subtle. Seizures, however, provide intense and synchronous, yet sparse activation (Bower et al., 2012) that could produce a stronger consolidation effect if seizures activate learning-related mechanisms similar to those activated by learned tasks. Continuous wide-bandwidth recordings from patients undergoing intracranial monitoring for drug-resistant epilepsy revealed reactivation of seizure-related neuronal activity during subsequent SWS, but not wakefulness. Those neuronal assemblies that were most strongly activated during seizures showed the largest correlation changes, suggesting that consolidation selectively strengthened neuronal circuits activated by seizures. These results suggest that seizures "hijack" physiological learning mechanisms and also suggest a novel epilepsy therapy targeting neuronal dynamics during post-seizure sleep.

  • Evidence for solid state electrochemical degradation within a small molecule OLED
    • Przemysław Data
    • Agnieszka Swist
    • Mieczysław Lapkowski
    • Jadwiga Soloduchno
    • Kazimierz Darowicki
    • Andrew P. Monkman
    2015 ELECTROCHIMICA ACTA

    Acridone derivative have been synthesised and used as OLED (Organic Light Emitting Diode) emitters which were found to be electroactive. Electrochemical investigations showed a side reaction takes place inside an active layer which diminished the overall device efficiency. By using a dopant and host active layer architecture, the formation of the by product was removed. The by-product was identified as a σ-dimer formed inside an oligomer. The active layers were investigated by electrochemical techniques (cyclic voltammetry, UV-Vis-NIR spectroelectrochemistry, Electron Paramagnetic Resonance (EPR) spectroelectrochemistry and Dynamic Electrochemical Impedance Spectroscopy (DEIS)) to characterize the layers, charge carriers, and electronic energy levels. It is clear from these observations that electrochemical reactions of emitter molecules in a working devices is a route to device degradation.

  • Evolutionary Planning of Safe Ship Tracks in Restricted Visibility
    • Rafał Szłapczyński
    2015 JOURNAL OF NAVIGATION

    The paper presents the continuation of the author's research on ship track planning by means of Evolutionary Algorithms (EA). The presented method uses EA to search for an optimal set of safe tracks for all ships involved in an encounter. Until now the method assumed good visibility – compliance with standard rules of the Convention on the International Regulations for Preventing Collisions at Sea (COLREGS, 1972). However, in restricted visibility, when Rule 19 applies instead of Rules 11 to 18, the problem is a different one. Therefore this paper introduces the extended method, with a focus on compliance with Rule 19 and its implications. It includes descriptions of detecting, penalizing and eliminating violations of Rule 19. The method has been implemented and the paper contains sample results of computer simulation tests carried out for ship encounters in restricted visibility in both open and restricted waters. They confirm the effectiveness of the chosen approach and suggest that the method could be applied in on board decision support systems.

  • Ewolucja projektu konwersji autobusów na trolejbusy w Gdyni
    • Marcin Połom
    • Mikołaj Bartłomiejczyk
    2015 Full text Autobusy. Technika, Eksploatacja, Systemy Transportowe

    Koszty zakupu taboru w komunikacji elektrycznej są istotnym czynnikiem kształtującym jej funkcjonowanie. W przypadku trolejbusów, przy ograniczonym rynku producentów i klientów, ceny nowych pojazdów są stosunkowo wysokie. Trolejbusy niskopodłogowe – wytwarzane przez producentów w Unii Europejskiej i Szwajcarii - dostosowane są indywidualnie do wymagań przewoźników. Zakup pojazdów z rynku wtórnego jest bardzo ograniczony. Podczas gdy zakup używanych autobusów jest zjawiskiem powszechnym, dla wielu spółek przewozowych odnowa taboru trolejbusowego stanowi problem. Gdyńskie Przedsiębiorstwo Komunikacji Trolejbusowej od 2003 r. wprowadza w życie projekt konwersji autobusów niskopodłogowych na trolejbusy. W artykule przedstawiono ewolucję tego projektu w latach 2011-2014, polegająca na zastosowaniu zdywersyfikowanych nadwozi i nowoczesnych rozwiązań napędowych.

  • Ewolucja projektu konwersji autobusów niskopodłogowych na trolejbusy w Gdyni
    • Marcin Połom
    • Mikołaj Bartłomiejczyk
    2015 Logistyka

    Koszty zakupu taboru w komunikacji elektrycznej są istotnym czynnikiem kształtującym jej funkcjonowanie. W przypadku trolejbusów, przy ograniczonym rynku producentów i klientów ceny nowych pojazdów są stosunkowo wysokie. Trolejbusy niskopodłogowe produkowane przez producentów w Unii Europejskiej i Szwajcarii dostosowywane są indywidualnie do wymagań przewoźników. Zakup pojazdów z rynku wtórnego jest bardzo ograniczony. Przed spółkami przewozowymi, w odróżnieniu od powszechnego zakupu autobusów używanych, stoi trudne wyzwanie odnowy taboru. Gdyńskie Przedsiębiorstwo Komunikacji Trolejbusowej od 2003 r. wprowadza w życie projekt konwersji autobusów niskopodłogowych na trolejbusy. W artykule przedstawiono ewolucję tego projektu w latach 2011-2014, polegającą na zastosowaniu zdywersyfikowanych nadwozi i nowoczesnych rozwiązań napędowych.

  • Examination of cyp51A and cyp51B expression level of the first Polish azole resistant clinical Aspergillus fumigatus isolate
    • Anna Brillowska-Dąbrowska
    • Martyna Mroczyńska
    • Urszula Nawrot
    • Katarzyna Włodarczyk
    • Ewelina Kurzyk
    2015 Full text Acta Biochimica Polonica

    Aspergillus fumigatus is one of the most prevalent airborne fungal pathogens causing infections worldwide. Most A. fumigatus strains are susceptible to azoles, which are administered as the first line therapeutics. However, during last decade the acquired resistance to triazoles by these species has been described. There is a number of publications concerning the examination of clinical A. fumigatus strains from different countries, however there has been no report from Poland. Here, we describe for the first time, an examination of cyp51A and cyp51B expression level of 11 clinical A. fumigatus strains isolated during 2007-2014 period from the collection of Medical University in Wrocław. Their susceptibility to itraconazole, voriconazole and posaconazole has been examined. The MIC values of triazoles for one of the examined isolates were respectively: > 8 mg/L for itraconazole, 2 mg/L for voriconazole and 0.5 mg/L for posaconazole. The cyp51A gene with its promoter region of all isolates was sequenced. It was found that the resistant isolate harbors the TR34/L98H mutation in the cyp51A gene and when cultured on media supplemented with voriconazole exhibits overexpression of both, cyp51A and cyp51B genes. The level of cyp51A gene expression was about 50 times higher than cyp51B.

  • Examining Influence of Distance to Microphone on Accuracy of Speech Recognition
    • Piotr Bratoszewski
    • Marcin Szykulski
    • Andrzej Czyżewski
    2015

    The problem of controlling a machine by the distant-talking speaker without a necessity of handheld or body-worn equipment usage is considered. A laboratory setup is introduced for examination of performance of the developed automatic speech recognition system fed by direct and by distant speech acquired by microphones placed at three different distances from the speaker (0.5 m to 1.5 m). For feature extraction from the voice signal the Mel- Frequency Cepstral Coefficients (MFCC) are used. The experiments are conducted employing the HTK engine (Hidden Markov Toolkit) for the Automatic Speech Recognition (ASR) task. The dictionary of 184 words was employed and WER (Word Error Rate), correctness and accuracy measures were calculated in order to verify and to compare obtained results of speech recognition.

  • Examples of numerical simulations of two-dimensional unsaturated flow with VS2DI code using different interblock conductivity averaging schemes
    • Adam Szymkiewicz
    • Witold Tisler
    • Kazimierz Burzyński
    2015 Full text GEOLOGOS

    Flow in unsaturated porous media is commonly described by the Richards equation. This equation is strongly nonlinear due to interrelationships between water pressure head (negative in unsaturated conditions), water content and hydraulic conductivity. The accuracy of numerical solution of the Richards equation often depends on the method used to estimate average hydraulic conductivity between neighboring nodes or cells of the numerical grid. The paper presents application of the computer simulation code VS2DI to three test problems concerning infiltration into initially dry medium, using various methods for inter-cell conductivity calculation (arithmetic mean, geometric mean and upstream weighting). It is shown that the influence of the averaging method can be very large for coarse grid, but diminishes as the cell size decreases. Overall, the arithmetic average produced the most reliable results for coarse grids. Moreover, the difference between results obtained with various methods is a convenient indicator of the adequacy of grid refinement.

  • Exergy analysis of the Szewalski cycle with a waste heat recovery system
    • Tomasz Kowalczyk
    • Paweł Ziółkowski
    • Janusz Badur
    2015 Full text Archives of Thermodynamics

    The conversion of a waste heat energy to electricity is now becoming one of the key points to improve the energy efficiency in a process engineering. However, large losses of a low-temperature thermal energy are also present in power engineering. One of such sources of waste heat in power plants are exhaust gases at the outlet of boilers. Through usage of a waste heat regeneration system it is possible to attain a heat rate of approximately 200 MWth, under about 90 ◦C, for a supercritical power block of 900 MWel fuelled by a lignite. In the article, we propose to use the waste heat to improve thermal efficiency of the Szewalski binary vapour cycle. The Szewalski binary vapour cycle provides steam as the working fluid in a high temperature part of the cycle, while another fluid – organic working fluid – as the working substance substituting conventional steam over the temperature range represented by the low pressure steam expansion. In order to define in detail the efficiency of energy conversion at various stages of the proposed cycle the exergy analysis was performed. The steam cycle for reference conditions, the Szewalski binary vapour cycle as well as the Szewalski hierarchic vapour cycle cooperating with a system of waste heat recovery have been comprised.

  • Exergy Losses in the Szewalski Binary Vapor Cycle
    • Tomasz Kowalczyk
    • Paweł Ziółkowski
    • Janusz Badur
    2015 Full text ENTROPY

    In this publication, we present an energy and exergy analysis of the Szewalski binary vapor cycle based on a model of a supercritical steam power plant. We used energy analysis to conduct a preliminary optimization of the cycle. Exergy loss analysis was employed to perform a comparison of heat-transfer processes, which are essential for hierarchical cycles. The Szewalski binary vapor cycle consists of a steam cycle bottomed with an organic Rankine cycle installation. This coupling has a negative influence on the thermal efficiency of the cycle. However, the primary aim of this modification is to reduce the size of the power unit by decreasing the low-pressure steam turbine cylinder and the steam condenser. The reduction of the “cold end” of the turbine is desirable from economic and technical standpoints. We present the Szewalski binary vapor cycle in addition to a mathematical model of the chosen power plant’s thermodynamic cycle. We elaborate on the procedure of the Szewalski cycle design and its optimization in order to attain an optimal size reduction of the power unit and limit exergy loss.

  • Exhaust gas temperature measurements in diagnostics of turbocharged marine internal combustion engines. Part I. Standard measurements.
    • Zbigniew Korczewski
    2015 Full text Polish Maritime Research

    The article discusses the problem of diagnostic informativeness of exhaust gas temperature measurements in turbocharged marine internal combustion engines. Theoretical principles of the process of exhaust gas flow in turbocharger inlet channels are analysed in its dynamic and energetic aspects. Diagnostic parameters are defined which enable to formulate general evaluation of technical condition of the engine based on standard online measurements of the exhaust gas temperature. A proposal is made to extend the parametric methods of diagnosing workspaces in turbocharged marine engines by analysing time-histories of enthalpy changes of the exhaust gas flowing to the turbocompressor turbine. Such a time-history can be worked out based on dynamic measurements of the exhaust gas temperature, performed using a specially designed sheathed thermocouple. The first part of the article discusses possibilities to perform diagnostic inference about technical condition of a marine engine with pulse turbocharging system based on standard measurements of exhaust gas temperature in characteristic control cross-sections of its thermal and flow system. Selected metrological issues of online exhaust gas temperature measurements in those engines are discusses in detail, with special attention being focused on the observed disturbances and thermodynamic interpretation of the recorded measuring signal. Diagnostic informativeness of the exhaust gas temperature measurements performed in steady-state conditions of engine operation is analysed in the context of possible evaluations of technical condition of the engine workspaces, the injection system, and the fuel delivery process.

  • Existence and uniqueness of solutions for single-population McKendrick-von Foerster models with renewal
    • Agnieszka Bartłomiejczyk
    • Henryk Leszczyński
    • Piotr Zwierkowski
    2015 Full text ROCKY MOUNTAIN JOURNAL OF MATHEMATICS

    We study a McKendrick-von Foerster type equation with renewal. This model is represented by a single equation which describes one species which produces young individuals. The renewal condition is linear but takes into account some history of the population. This model addresses nonlocal interactions between individuals structured by age. The vast majority of size-structured models are also treatable. Our model generalizes a number of earlier models with delays and integrals. The existence and uniqueness is proved through a fixed-point approach to an equivalent integral problem.

  • Expedited Geometry Scaling of Compact Microwave Passives by Means of Inverse Surrogate Modeling
    • Sławomir Kozieł
    • Adrian Bekasiewicz
    2015 IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES

    In this paper, the problem of geometry scaling of compact microwave structures is investigated. As opposed to conventional structures (i.e., constructed using uniform transmission lines), re-design of miniaturized circuits (e.g., implemented with artificial transmission lines, ATSs) for different operating frequencies is far from being straightforward due to considerable cross-couplings between the circuit components. Here, we develop a simple and computationally efficient methodology for dimension scaling of the compact circuits. The proposed approach utilizes an equivalent circuit representation to identify a fast inverse model that determines the relationship between the geometry parameters of the structure at hand and its operating frequency. Upon suitable correction, the inverse model is applied to find dimensions of the scaled design at the high-fidelity (EM-simulation) model level. Owing to reasonable correlations between the low- and high-fidelity models, the circuit geometry scaled to a requested operating frequency can be found using just a single EM simulation of the structure, despite possible (and normally large) absolute discrepancies between the models. The proposed methodology is demonstrated using two exemplary compact couplers scaled in wide ranges of 0.5 GHz to 2 GHz, and 0.5 GHz to 1.8 GHz, respectively. The numerical results are supported by physical measurements of the fabricated coupler prototypes.

  • Expedited Multi-Objective Design Optimization of Miniaturized Microwave Structures Using Physics-Based Surrogates
    • Sławomir Kozieł
    • Adrian Bekasiewicz
    • Piotr Kurgan
    • John W. Bandler
    2015

    In this paper, a methodology for fast multi-objective design optimization of compact microwave circuits is presented. Our approach exploits an equivalent circuit model of the structure under consideration, corrected through implicit and frequency space mapping, then optimized by a multi-objective evolutionary algorithm. The correction/optimization of the surrogate is iterated by design space confinement and segmentation based on a Pareto set representation obtained thus far in the process, aiming at improving the surrogate model in the vicinity of the Pareto-optimal solutions. Our technique is demonstrated by the design of a folded rat-race coupler.

  • Experience oriented enhancement of smartness for Internet of Things
    • Haoxi Zhang
    • Cesar Sanin
    • Edward Szczerbicki
    2015

    In this paper, we propose a novel approach, the Experience-Oriented Smart Things that allows experiential knowledge discovery, storage, involving, and sharing for Internet of Things. The main features, architecture, and initial experiments of this approach are introduced. Rather than take all the data produced by Internet of Things, this approach focuses on acquiring only interesting data for its knowledge discovery process. By catching decision events, this approach gathers its own daily operation experience, which is the interesting data, and uses such experience for knowledge discovery. An initial experiment was made at the end of this paper, by applying this approach to a sensors-equipped bicycle, the bicycle is able to learn user’s physical features and recognize its user out of other riders. Customized version of Decisional DNA is used in this approach as the knowledge representation technique. Decisional DNA is a domain-independent, and flexible, and standard experiential knowledge repository solution that allows knowledge to be acquired, reused, evolved and shared easily. The presented conceptual approach demonstrates how knowledge can be discovered through its domain’s experiences and stored as Decisional DNA.