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Gdańsk University of Technology

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Publications from the year 2014

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  • Evolutionary sets of safe ship trajectories with speed reduction manoeuvres within traffic separation schemes
    • Rafał Szłapczyński
    2014 Full text Polish Maritime Research

    In the previous paper the author presented the evolutionary ship trajectory planning method designed to support Traffic Separation Schemes (TSS). This time the extensions of this method are described which allow to combine evolutionary trajectory planning with speed reduction manoeuvres. On TSS regions with higher than usual density of traffic and smaller distances between ships, the course alterations alone are not always sufficient or effective means of collision avoidance. Therefore they must be supplemented by speed reduction manoeuvres to a larger extent than on open waters. The paper includes a brief description of the optimisation problem, descriptions of the new elements of the method (fitness function, algorithms and the evolutionary cycle) and the examples of how the extended method successfully solves the problems unsolvable without applying speed reduction.

  • Ewolucja polityki instytucjonalnej rynku pracy w Polsce
    • Dagmara Nikulin
    2014 Full text Przestrzeń Ekonomia Społeczeństwo

    Celem artykułu jest przedstawienie zmian, jakie miały miejsce w polskiej polityce rynku pracy w kontekście instytucjonalnym. Artykuł składa się z części teoretycznej, zawierającej omówienie podstaw polityki rynku pracy w rozróżnieniu na politykę aktywną oraz pasywną, jak również prezentującej najważniejsze zmiany, jakie miały miejsce na polskim rynku pracy po roku 1989, a w szczególności po wstąpieniu Polski do Unii Europejskiej. W części empirycznej zbadano strukturę wydatków związanych z realizacją polityki rynku pracy w Polsce. Skonfrontowano w tym celu wydatki na instrumenty aktywne oraz pasywne w latach 2005–2011 w Polsce oraz krajach Unii Europejskiej. W wyniku przeprowadzonych badań udzielono odpowiedzi na pytanie o kierunek zmian zachodzących na polskim rynku pracy w kontekście czynników instytucjonalnych.

  • Ewolucyjne planowanie bezpiecznych trajektorii statków oparte na zmodyfikowanym diagramie Cockcrofta.
    • Rafał Szłapczyński
    2014 Logistyka

    Artykuł przedstawia kontynuację badań autora nad planowaniem bezpiecznych trajektorii statków za pomocą algorytmów ewolucyjnych. Prezentowana metoda poszukuje optymalnego zbioru bezpiecznych trajektorii wszystkich statków biorących udział w spotkaniu. Bieżąca wersja metody zakłada ograniczoną widoczność i obowiązywanie Prawidła 19 Międzynarodowych Przepisów o Zapobieganiu Zderzeniom na Morzu (MPZZM) zamiast Prawideł 11 – 18. Artykuł skupia się na zapewnieniu zgodności wyników z Prawidłem 19, oraz z jego interpretacją [2]. Zawiera on opis sposobów wykrywania i usuwania naruszeń Prawidła 19 oraz wyniki komputerowych symulacji przeprowadzonych dla wód otwartych oraz ograniczonych. Wyniki potwierdzają skuteczność metody i możliwość zastosowania jej w pokładowym systemie wspomagania decyzji nawigatora. Słowa kluczowe: ograniczona widoczność, algorytmy ewolucyjne, manewry antykolizyjne, diagram Cockcrofta.

  • Exact modal absorbing boundary condition for waveguide simulations - discrete Green's function approach
    • Michał Wiktor
    • Tomasz Stefański
    2014

    A modal absorbing boundary condition (ABC) based on the discrete Green's function (DGF) is introduced and applied for termination of waveguides simulated by means of the finite-difference time-domain (FDTD) method. The differences between the developed approach and implementations already demonstrated in the literature are presented. By applying DGF, a consistent theoretical approach to modal ABC in the FDTD method is obtained. Developed ABC is applicable to propagating and evanescent modes yielding the reflection error below -250 dB. Because the perfect matching may be computationally expensive, results of investigations of the tradeoff between computational efficiency and accuracy of the developed method are presented.

  • Examining Acoustic Emission of Engineered Ultrasound Loudspeakers
    • Piotr Bratoszewski
    • Janusz Cichowski
    • Andrzej Czyżewski
    2014

    Measurement results of the sound emitted from an ultrasound custom-made system with high spatial directivity are presented. The proposed system is using modulated ultrasound waves which demodulate in nonlinear medium resulting in audible sound. The system is aimed at enhancing the users’ personal audio space, therefore the measurements are performed using the Head and Torso Simulator which provides the realistic reproduction of the human auditory system. Based on the measurements of the sound emitted from the two parametric arrays of ultrasonic transducers the directivity of the proposed system and the interaural crosstalk characteristics are determined. The application of the system concerns creating a personal audio space for users of mobile platforms, such as notebooks, and applying 3D audio algorithms without the need of using headphones.

  • EXAMINING INFLUENCE OF VIDEO FRAMERATE AND AUDIO/VIDEO SYNCHRONIZATION ON AUDIO-VISUAL SPEECH RECOGNITION ACCURACY
    • Piotr Bratoszewski
    • Kuba Łopatka
    • Andrzej Czyżewski
    2014

    The problem of video framerate and audio/video synchronization in audio-visual speech recogni-tion is considered. The visual features are added to the acoustic parameters in order to improve the accuracy of speech recognition in noisy conditions. The Mel-Frequency Cepstral Coefficients are used on the acoustic side whereas Active Appearance Model features are extracted from the image. The feature fusion approach is employed. The initial video framerate equals 100 frames per second. The test signals were recorded with a specialized hardware for synchronous registration of audio and video data. In a practical implementation, however, it is difficult to achieve a high rate of images per second and maintain the precise audio/video synchronization. Therefore, in this work it is assessed, how the lowered framerate and lack of synchronization be-tween audio and video data impairs the performance of the recognition engine. The lowered video framerate is enforced by downsampling the visual data. The lack of synchronization is simulated programmatically in the feature fusion process. The experiments are conducted employing the HTK engine (Hidden Markov Toolkit). Word Error Rate, correctness and accuracy measures are considered and a small dictionary of 11 words (numerals) is employed.

  • EXAMINING INFLUENCE OF VIDEO FRAMERATE AND AUDIO/VIDEO SYNCHRONIZATION ON AUDIO-VISUAL SPEECH RECOGNITION ACCURACY
    • Piotr Bratoszewski
    • Kuba Łopatka
    • Andrzej Czyżewski
    2014

    The problem of video framerate and audio/video synchronization in audio-visual speech recognition is considered. The visual features are added to the acoustic parameters in order to improve the accuracy of speech recognition in noisy conditions. The Mel-Frequency Cepstral Coefficients are used on the acoustic side whereas Active Appearance Model features are extracted from the image. The feature fusion approach is employed. The initial video framerate equals 100 frames per second. The test signals were recorded with a specialized hardware for synchronous registration of audio and video data. In a practical implementation, however, it is difficult to achieve a high rate of images per second and maintain the precise audio/video synchronization. Therefore, in this work it is assessed, how the lowered framerate and lack of synchronization between audio and video data impairs the performance of the recognition engine. The lowered video framerate is enforced by downsampling the visual data. The lack of synchronization is simulated programmatically in the feature fusion process. The experiments are conducted employing the HTK engine (Hidden Markov Toolkit). Word Error Rate, correctness and accuracy measures are considered, while a small dictionary of 11 words (numerals) is employed.

  • Examining Quality of Hand Segmentation Based on Gaussian Mixture Models
    • Michał Lech
    • Piotr Dalka
    • Grzegorz Szwoch
    • Andrzej Czyżewski
    2014

    Results of examination of various implementations of Gaussian mix-ture models are presented in the paper. Two of the implementations belonged to the Intel’s OpenCV 2.4.3 library and utilized Background Subtractor MOG and Background Subtractor MOG2 classes. The third implementation presented in the paper was created by the authors and extended Background Subtractor MOG2 with the possibility of operating on the scaled version of the original video frame and additional image post-processing phase. The algorithms have been evaluated for various conditions related to stability of background. The quality of hand segmentation when a whole user’s body is visible in the video frame and when only a hand is present has been assessed. Three measures, based on false negative and false positive errors, were calculated for the as-sessment of segmentation quality, i.e. precision, recall and accuracy factors.

  • Exchange Traded Funds (ETFs) rynków wschodzących
    • Adam Marszk
    2014

    ETFs są instrumentami umożliwiającymi osiąganie przez inwestorów szeregu korzyści, zwłaszcza w zestawieniu z tradycyjnymi funduszami. O wysokim zainteresowaniu ETFs świadczą rosnące rozmiary rynku. Jednak wzrost zróżnicowania ETFs i wprowadzenie na rynek funduszy syntetycznych sprawiły, że pojawiły się nowe czynniki ryzyka, które muszą zostać uwzględnione zarówno przez podmioty biorące udział w obrotach, jak i przez instytucje dbające o stabilność systemu finansowego. Główną grupą ETFs są fundusze oparte na rynkach akcji krajów wysoko rozwiniętych, znaczenie ETFs rynków wschodzących jest niewielkie. Można jednak wyróżnić kilka krajów wschodzących, z których rynkami powiązane są ETFs o stosunkowo wysokiej wartości aktywów – Chiny (obok USA i Japonii jeden z najważniejszych rynków w skali całego świata), Koreę Płd., Meksyk i Brazylię. W większości krajów wschodzących brak ETFs notowanych na miejscowych giełdach (dotyczy to w szczególności mniejszych krajów), ETFs oparte na indeksach tych rynków akcji są także rzadko notowane na giełdach w krajach wysoko rozwiniętych. Problem przyczyn zacofania rynku ETFs i perspektyw jego rozwoju w krajach wschodzących może być przedmiotem dalszych badaniach obejmujących m.in. kwestie otoczenia regulacyjnego systemów finansowych, zaawansowania technologicznego (w zakresie mechanizmów handlu oraz dostępu do informacji na rynku akcji), wpływu zmian popytu ze strony inwestorów zagranicznych oraz krajowych.

  • EXHAUST TEMPERATURE MEASUREMENTS OF THE MARINE TURBOCHARGED DIESEL ENGINES IN OPERATION
    • Zbigniew Korczewski
    2014 Full text Journal of Polish CIMEEAC

    The article presents the selected metrology issues concerning the exhaust temperature of the turbocharged marine engines during operation. The special concern has been paid on existing disturbances as well as thermodynamical interpretation of the recorded measurement signal. A diagnostic informativeness of the standard exhaust temperature’s measurements has worked out while the engine runs in steady states has been also considered about many aspects of technical state evaluation of its working spaces, the fuel injection unit as well as the load exchange system.

  • Existence and uniqueness of monotone and bounded solutions for a finite-difference discretization a` la Mickens of the generalized Burgers–Huxley equation.
    • J. E. Macías-Díaz
    • Anna Szafrańska
    2014 JOURNAL OF DIFFERENCE EQUATIONS AND APPLICATIONS

    Departing from a generalized Burgers–Huxley partial differential equation, we provide a Mickens-type, nonlinear, finite-difference discretization of this model. The continuous system is a nonlinear regime for which the existence of travelling-wave solutions has been established previously in the literature. We prove that the method proposed also preserves many of the relevant characteristics of these solutions, such as the positivity, the boundedness and the spatial and the temporal monotonicity. The main results provide conditions that guarantee the existence and the uniqueness of monotone and bounded solutions of our scheme. The technique was implemented and tested computationally, and the results confirm both a good agreement with respect to the travelling-wave solutions reported in the literature and the preservation of the mathematical features of interest.

  • Existence of solutions with an exponential growth for nonlinear differential-functional parabolic equations
    • Agnieszka Bartłomiejczyk
    • Henryk Leszczyński
    2014 Full text Annales Polonici Mathematici

    We consider the Cauchy problem for nonlinear parabolic equations with functional dependence.We prove Schauder-type existence results for unbounded solutions. We also prove existence of maximal solutions for a wide class of differential functional equations.

  • Expedited design of microstrip antenna subarrays using surrogate-based optimization
    • Sławomir Kozieł
    • Stanislav Ogurtsov
    • Włodzimierz Zieniutycz
    • Łukasz Sorokosz
    2014 IEEE Antennas and Wireless Propagation Letters

    Computationally efficient simulation-driven design of microstrip antenna subarrays is presented. The proposed design approach aims at simultaneous adjustment of all relevant geometry parameters of the subarray, which allows us to take into account the effect of the feeding network on the subarray radiation pattern (in particular, the side lobe level, SLL). In order to handle a large number of variables involved in the design process, a surrogate-based optimization procedure is proposed that exploits EM array simulations of variable fidelity and suitably designed correction techniques. The penalty function approach allows us to minimize SLL while maintaining array matching at a required level. The optimized designs are obtained at the low computational cost corresponding to a few high-fidelity subarray simulations. Experimental validation of the manufactured designs of microstrip subarrays operating at 10 GHz is also provided.

  • Expedited EM-driven multi-objective antenna design in highly-dimensional parameter spaces
    • Sławomir Kozieł
    • Adrian Bekasiewicz
    • Włodzimierz Zieniutycz
    2014 IEEE Antennas and Wireless Propagation Letters

    A technique for low-cost multi-objective optimization of antennas in highly-dimensional parameter spaces is presented. The optimization procedure is expedited by exploiting fast surrogate models, including coarse-discretization EM antenna simulations and response surface approximations (RSA). The latter is utilized to yield an initial set of Pareto non-dominated designs which are further refined using response correction methods. Efficient handling of multiple geometry parameters is realized by the initial reduction of the solution space. Our approach is demonstrated using 13-parameter triple trapezoidal, planar ultra-wideband (UWB) monopole antenna.

  • Experience Visualizaton
    • Bartosz Kucharski
    • Edward Szczerbicki
    2014

    Set of Experience Knowledge Structure (SOEKS) has proved its capability of storing substantial part of experience at a particular decision point. The management of SOEKS record is also proposed in many papers for example referring to concepts of Decisional DNA knowledge representation, that is a collection of a number of SOEKS. The aim of this paper is to focus on visualization and practical aspects of presenting gathered knowledge to the end user.

  • Experiences from operation of various expansion devices in small scale ORC
    • Dariusz Mikielewicz
    • Jan Wajs
    • Jarosław Mikielewicz
    • Krzysztof Kosowski
    2014

    The main aim of this paper was to present various expansion devices for an application in the small scale ORC system. The investigations were carried out in two parallel directions. One direction was to design and construct a device dedicated to the analyzed ORC system. The second direction was to adapt existing expansion devices for the needs of the analyzed ORC system. Four various devices were described and presented together with the experimental results. The most promising seemed to be the vapour microturbine which was built from the beginning as the device ORC system oriented.

  • EXPERIMENTAL ANALYSIS OF RUBBER AND STYROFOAM BUMPERS INFLUENCE ON THE COLLIDING STRUCTURES
    • Barbara Sołtysik
    2014 Dokonania Młodych Naukowców

    Past and recent investigations of colliding structures under seismic excitation confirmed that pounding may have a significant influence on the structural response. Interactions between adjacent buildings may cause serious damage to the structures, leading even to its total collapse. The main reason of earthquake-induced pounding, besides insufficient distance between structures, are differences in stiffness or mass of colliding structures. The aim of this study is to show the results of experimental analysis focused on structural pounding between insufficiently separated buildings under earthquake excitation. To perform this study, models of three steel towers, with different dynamic parameters were constructed and mounted to the platform of a shaking table. The influence of rubber and styrofoam bumpers located in gap (=30 mm) was taken under consideration. Analyses were performed to answer the question if putting bumpers between two adjacent structures may prevent damage which were the result of pounding. Experimental study confirmed that earthquake-induced pounding may lead to changes of structural behaviour. Additionally, use of bumpers may lead to the decrease of structural response, as well as its increase, but the pattern of changes is not constant.

  • Experimental and numerical evaluation of mechanical behaviour of composite structural insulated panels
    • Łukasz Smakosz
    • Ireneusz Kreja
    2014

    Composite structural insulated panels (CSIPs) are novel prefabricated elements for structural applications. Panels under consideration are made from glass-fibre reinforced magnesia cement boards as facesheets and expanded polystyrene foam (EPS) as a core. Quasi-static full-scale and model bending tests under monotonic loading were performed to recognize mechanical properties of CSIPs in flexure. In addition, tensile, compressive, shear and flexural small-scale tests were performed in order to establish material properties of composing materials. A FEM computational model was then created in commercial code ABAQUS in order to predict the behaviour of CSIPs. The main aim of this paper is to present the results of numerical simulations of the selected small- and full-scale tests and to compare them with the experimental data in order to validate the presented FEM model.

  • EXPERIMENTAL AND NUMERICAL STUDY ON COLLISIONS BETWEEN STEEL STRUCTURES UNDER EARTHQUAKE EXCITATION
    • Barbara Sołtysik
    • Robert Jankowski
    2014

    In the time of high urbanization, the need to build closely-spaced structures forces the designers to take into account earthquake-induced collisions between adjacent buildings and their effects on the response of structures. Past and recent investigations confirmed that interactions between adjacent buildings during earthquakes may cause serious damages to the structural elements and may even lead to total collapse of the structure. The aim of the paper is to show the results of the experimental and numerical study focused on earthquake–induced pounding between adjacent steel structures in series. In the study, two analyses were performed using three steel towers with different dynamic parameters and various distance between structures. The results of the study indicate that collisions may significantly influence the structural behaviour, leading to the increase in the response

  • EXPERIMENTAL AND THEORETICAL FLOW OF THE FORCES IN DEEP BEAMS WITH CANTILEVAR
    • Krystyna Nagrodzka-Godycka
    • Anna Kopańska
    • Kamila Zmuda-Baszczyn
    2014

    This article presents the results of experimental research carried out on deep beams with cantilever which was loaded throughout the depth. The main deep beam was directly simply supported on the one side. On the other side the deep beam was suspended in another deep member situated at right angles. All deep beams created a spatial arrangement. The paper is focused on the analysis of the cracks morphology and flow of the internal forces in the cantilever deep beams. Experimental results in comparison with the theoretical as well as the current design recommendations were discussed.