Publications Repository - Gdańsk University of Technology

Page settings

polski
Publications Repository
Gdańsk University of Technology

Show publications from the year

Publications from the year 2015

Show all
  • Accelerated simulation-driven design optimisation of compact couplers by means of two-level space mapping
    • Adrian Bekasiewicz
    • Sławomir Kozieł
    • Bogdan Pankiewicz
    2015 Full text IET Microwaves Antennas & Propagation

    In this study, the authors discuss a robust and efficient technique for rapid design of compact couplers. The approach exploits two-level space mapping (SM) correction of an equivalent circuit model of the coupler structure under design. The first SM layer (local correction) is utilised to ensure good matching between the equivalent circuit and the electromagnetic model at the component level. Subsequent global correction allows for accounting the electromagnetic couplings between the components. The important advantage of two-level model correction is that small number of parameter is utilised at each stage, which substantially simplifies and speeds up the parameters extraction procedure. Another advantage is that the local-global SM results in considerably better generalisation capability of the surrogate model (as compared to conventional SM). This leads to improved reliability of the optimisation process and its reduced computational cost. The proposed technique is validated using an example of two compact microstrip rat-race couplers and compared with other surrogate-based optimisation techniques.

  • Acceleration of the DGF-FDTD method on GPU using the CUDA technology
    • Tomasz Dziubak
    • Michał Wiktor
    • Sławomir Orłowski
    • Tomasz Stefański
    2015

    We present a parallel implementation of the discrete Green's function formulation of the finite-difference time-domain (DGF-FDTD) method on a graphics processing unit (GPU). The compute unified device architecture (CUDA) parallel computing platform is applied in the developed implementation. For the sake of example, arrays of Yagi-Uda antennas were simulated with the use of DGF-FDTD on GPU. The efficiency of parallel computations is presented as a function of the number of current elements in such wire antennas. The speedup of the developed implementation approaches maximally 10 relative to the code executed on a multicore central processing unit (CPU). Furthermore, the hybrid technique combining FDTD and its convolution formulation based on DGF was implemented on a heterogeneous CPU-GPU system, facilitating our research on the DGF-FDTD method.

  • Acceptance Testing of Software Products for Cloud-Based On-Line Delivery
    • Bogdan Wiszniewski
    2015 Full text TASK Quarterly

    Software products intended for on-line delivery by distributors serving an open community of subscribers are developed in a specific life-cycle model, in which roles of the major stakeholders are strongly separated, unlike in any other software development model known in software engineering. Its specificity underlines the fact that a distributor of the final product, responsible for its acceptance for publication and delivery to subscribers (users), is not a member of the product development team. Similarly, users of the product, who normally act as clients in other software development models cannot participate in the process until it is published by a distributor. In the paper a test methodology defined by the industrial IEEE standard is analyzed in the context of that on-line delivery software development model and basic recommendation for the NIWA distribution platform to be operated by the CI-TASK Academic Computer Centre at Gdansk University of Technology are formulated.

  • Accuracy Analysis of Determination the Vertical Displacements in Unstable Reference System
    • Daria Filipiak-Kowszyk
    • Waldemar Kamiński
    • Marek Przyborski
    2015

    Measurements of horizontal and vertical displacements are carried out mostly based on reference points identified as fixed. In surveying practice there may be some situations in which there is not possible to perform the measurements with reference to stable points or the difficulties in identification of points’ stability may arise. Accuracy analysis based on the covariance matrices have a special role in this process. In presented paper the covariance matrices were determined. The authors took advantage of the method of determination the vertical displacements in the absence of stability of reference points. The paper presents algorithm of computation and also results of the empirical tests. Tests were carried out based on simulated data of foundation plate measurements. The conclusions, which came from the calculations, encourage not only to do more detailed analysis and tests but also to theoretical development of the presented method.

  • Acoustic journal bearing - A search for adequate configuration
    • Tadeusz Stolarski
    • Rafał Gawarkiewicz
    • Krzysztof Tesch
    2015 TRIBOLOGY INTERNATIONAL

    Classical non-contact bearings are already used in a number of specialist applications but there are somespecialist areas where they cannot be used for variety of reasons and acoustic sliding bearings could be an alternative. The paper presents the quest for a configuration of an acoustic journal bearing and shows that the overall shape of the bearing and its geometry are of a vital importance for the load capacity oft he bearing. The results clearly demonstrate that the acoustic journal bearing with appropriate geometry can develop a load capacity of magnitude that can be sufficient for some practical applications. The search for the appropriate configuration was carried out using finite element modelling and experimental validating testing.

  • Acquisition and indexing of RGB-D recordings for facial expressions and emotion recognition
    • Mariusz Szwoch
    2015 Studia Informatica Pomerania

    In this paper KinectRecorder comprehensive tool is described which provides for convenient and fast acquisition, indexing and storing of RGB-D video streams from Microsoft Kinect sensor. The application is especially useful as a supporting tool for creation of fully indexed databases of facial expressions and emotions that can be further used for learning and testing of emotion recognition algorithms for affect-aware applications. KinectRecorder was successfully exploited for creation of Facial Expression and Emotion Database (FEEDB) significantly reducing the time of the whole project consisting of data acquisition, indexing and validation. FEEDB has already been used as a learning and testing dataset for a few emotion recognition algorithms which proved utility of the database, and the KinectRecorder tool.

  • Active and Dynamic Graphical Code for Object Identification in Healthcare
    • Adam Bujnowski
    • Martin Benoit
    • Mariusz Kaczmarek
    • Piotr Przystup
    • Jacek Rumiński
    • Isabelle Pecci
    2015 Journal of Medical Imaging and Health Informatics

    A new approach for item marking using two dimensional discrete graphics markers. Proposed solution allow o change the code rapidly, upon request and in the case of thermal markers make the code invisible for unauthorized observers. Connecting the proposed codes with wearable multmedial platform such as eGlasses can create new possibilities in human-environment interaction.

  • Active feedback noise control in the presence of impulsive disturbances
    • Maciej Niedźwiecki
    • Michał Meller
    2015

    The problem of active feedback control of a narrowband acoustic noise in the presence of impulsive disturbances is considered. It is shown that, when integrated with appropriately designed outlier detector, the proposed earlier feedback control algorithm called SONIC is capable of isolating and rejecting noise pulses. According to our tests this guarantees stable and reliable operation of the closed-loop noise cancelling system.

  • Active management of equipment cooling in hoteling data centers
    • Artur Opaliński
    2015 Full text Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Hoteling data centers are designated for housing computing and storage units of many, usually small customers, as opposed to traditional data centers supporting own computing and storage resources of a bigger company. One of the services to be provided to consumer’s equipment is cooling. Cooling in data centers is prevalently achieved by circulating air in computer room. Efficient cooling requires delivering cold air from central cooling units directly to the equipment that needs it, in appropriate quantity, and at the right time. But with centralized cooling, hot spots and cold spots arise in computer room, caused by uneven, uncontrolled heat generation. The proposed active cold air flow management is to periodically input data from sensors into a model which calculates parameters at every floor localization based on measurements taken at the most reliable measurement locations. Such model has been created and verified by implementation in an industrial data center

  • Adaptacja kulturowa jako wyzwanie w zespołachmiędzynarodowych
    • Beata Krawczyk-Bryłka
    • Dominika Fijałkowska
    2015 Full text Przedsiębiorczość i Zarządzanie

    Wyzwania dotyczące pracy w międzykulturowym środowisku są najczęściej odnoszone do menedżerów, ze względu na powszechność ich międzynarodowych migracji oraz podejmowanie międzynarodowej współpracy z kooperantami. Rozwój globalnego rynku pracy stymuluje jednak również szeregowych pracowników do poszukiwania pracy w różnych krajach, co sprawia, że wielu z nich pracuje w międzykulturowych zespołach, gdzie doświadczają kulturowego szoku i musza zaadaptować swój styl pracy do kulturowych wymogów. Zadaniem liderów jest wówczas przygotowanie członków zespołu do pracy w warunkach kulturowej różnorodności. Celem artykułu jest podkreślenie znaczenia perspektywy pracowników w procesie adaptacji wielokulturowej oraz opracowanie rekomendacji dla liderów zespołów międzykulturowych, których to zadanie dotyczy. Oparto je o badanie na grupie 50 pracowników zatrudnionych w międzykulturowych organizacjach. Zaproponowano szereg narzędzi wspierających prawidłowy proces adaptacji pracowników do pracy w zespole wielokulturowym.

  • ADAPTACYJNY DOBÓR KROKU OBLICZEŃ DLA SYMULATORA CZASU RZECZYWISTEGO O MIĘKKICH WYMAGANIACH CZASOWYCH
    • Jarosław Tarnawski
    • Tomasz Karla
    • Tomasz Adam Rutkowski
    • Bartosz Puchalski
    • Kazimierz Duzinkiewicz
    2015 Full text Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Symulacje czasu rzeczywistego mają duże walory praktyczne i dydaktyczne w zastosowaniach automatyki. Praca z symulatorem czasu rzeczywistego pozwala na poznaniei doświadczenie dynamiki symulowanego obiektu, wprowadzanie sterowań oraz decyzji operatorskich w warunkach czasowych odpowiadających rzeczywistemu obiektowi. Realizacja symulatorów czasu rzeczywistego wymaga zakończenia obliczeń numerycznych jednego kroku symulatora w czasie krótszym niż założona długość kroku symulacji. Jest to wyzwanie zwłaszcza dla małych kroków symulacji. Innego typu problemem jest realizacja symulatora czasu rzeczywistego o wymaganiach miękkich (tj. z możliwymi incydentalnymi naruszeniami ograniczeń na czas obliczeń numerycznych) w środowisku obliczeniowym nie będącym systemem czasu rzeczywistego. Wobec powyższych wymagań i ograniczeń konieczne jest rozwiązanie zawierające kompromis pomiędzy nadążaniem za czasem symulacji kosztem wydłużania kroku symulacji co może powodować pogorszenie wyników symulacji. W artykule rozpatrywane jest zagadnienie adaptacyjnego doboru kroku symulacji zastosowane dla symulatora procesów reaktora jądrowego.

  • Adaption of Open Science Paradigm at Gdańsk University of Technology
    • Tomasz Maria Boiński
    2015 Full text TASK Quarterly

    Open Access plays growing role in sharing results of today's research. The movement is very strong and many Universities, including Gdańsk University of Technology, are adapting this approach. This paper presents general information about Open Access movement and the approach adapted by the Gdańsk University of Technology. The components of Open Science platform as well as the procedures are described.

  • ADAPTIVE IDENTIFICATION OF TIME-VARYING IMPULSE RESPONSE OF UNDERWATER ACOUSTIC COMMUNICATION CHANNEL
    • Iwona Kochańska
    2015 Full text HYDROACOUSTICS

    The transmission properties of underwater acoustic communication channel can change dynamically due to the movement of acoustic system transmitter and receiver or underwater objects reflecting transmitted signal. The time-varying impulse response measurement and estimation are necessary to match the physical layer of data transmission to instantaneous channel propagation conditions. Using the correlative measurement method, impulse response estimate can be obtained no more than the duration of the measurement sequence. The paper proposes a joint correlative measurement and adaptive filtration approach, applying the Kalman filter algorithm to increase the time-domain resolution of the time-varying impulse response estimation.

  • Adaptive system for recognition of sounds indicating threats to security of people and property employing parallel processing of audio data streams
    • Kuba Łopatka
    2015

    A system for recognition of threatening acoustic events employing parallel processing on a supercomputing cluster is featured. The methods for detection, parameterization and classication of acoustic events are introduced. The recognition engine is based onthreshold-based detection with adaptive threshold and Support Vector Machine classifcation. Spectral, temporal and mel-frequency descriptors are used as signal features. The algorithms are implemented in a supercomputing environment utilizing a specializedframework for processing multimedia data streams. The recognition engine is evaluated in various conditions, both using pre-recorded signals and real-world events. First, an evaluation in laboratory conditions is performed to simulate selected acoustic environ-ments and evaluate the recognition rates in noise. Subsequently, the recognition rates are assessed in various practical situations (related to indoor and outdoor surveillance)and compared with the results obtained in simulations. The adaptation of event detection evaluated by comparing dierent approaches to adapting the detection thresholds. Finally, parallel processing is introduced to improve the performance of the developedrecognition engine. The experiments utilizing a supercomputing platform are introduced, which show that the employment of parallel processing leads to signicant shortening of the time required to make the decision. The possible practical applications ofthe developed methods are outlined, including surveillance of urban space, public events or private property.

  • Advanced Control Structures of Turbo Generator System of Nuclear Power Plant
    • Paweł Sokólski
    • Karol Kulkowski
    • Anna Kobylarz
    • Kazimierz Duzinkiewicz
    • Tomasz Adam Rutkowski
    • Michał Grochowski
    2015

    In the paper a synthesis of advanced control structures of turbine and synchronous generator for nuclear power plant working under changing operating conditions (supplied power level) is presented. It is based on the nonlinear models of the steam turbine and synchronous generator cooperating with the power system. Considered control structure consists of multi-regional fuzzy control systems with local linear controllers, including PID controllers, in particular control loops of turbine and generator. Soft switching between the local controllers is performed by TakagiSugeno-Kang fuzzy logic mechanism. Parameters of the local controllers were optimally tuned for a priori chosen operating points within the range 50–100% of nominal active power generated by the synchronous generator. Simulation results show that proposed advanced control structure is superior to widely used classic control structure (local controllers tuned for nominal operating points). During simulations the data of the real devices were used, respectively for the 4 CK 465 steam turbine and synchronous generator GTHW-600, which were planned to be used in the first Polish nuclear power plant in Żarnowiec.

  • Advanced Control Structures of Turbo Generator System of Nuclear Power Plant
    • Paweł Sokólski
    • Karol Kulkowski
    • Anna Kobylarz
    • Kazimierz Duzinkiewicz
    • Tomasz Adam Rutkowski
    • Michał Grochowski
    2015 Full text Acta Energetica

    In the paper a synthesis of advanced control structures of turbine and synchronous generator for nuclear power plant working under changing operating conditions (supplied power level) is presented. It is based on the nonlinear models of the steam turbine and synchronous generator cooperating with the power system. Considered control structure consists of multi-regional fuzzy control systems with local linear controllers, including PID controllers, in particular control loops of turbine and generator. Soft switching between the local controllers is performed by TakagiSugeno-Kang fuzzy logic mechanism. Parameters of the local controllers were optimally tuned for a priori chosen operating points within the range 50–100% of nominal active power generated by the synchronous generator. Simulation results show that proposed advanced control structure is superior to widely used classic control structure (local controllers tuned for nominal operating points). During simulations the data of the real devices were used, respectively for the 4 CK 465 steam turbine and synchronous generator GTHW-600, which were planned to be used in the first Polish nuclear power plant in Żarnowiec.

  • Advanced Monte Carlo simulator of the polarization-sensitive optical coherence tomography systems
    • Maciej Kraszewski
    • Michał Trojanowski
    • Jerzy Pluciński
    • Marcin Strąkowski
    2015

    Simulations of the optical coherence tomography (OCT) systems using the Monte Carlo method is a widely explored research area. However, there are several difficulties that need to be overcome in order to properly model the OCT imaging with the Monte Carlo algorithm. First of all, the temporal and the spatial coherence of the scattered light need to be considered, since OCT is based on the interference phenomenon. For the same reason, the polarization state of the scattered light need to be calculated. Moreover, the OCT systems use light beams that can be described by the Gaussian beam model. However, such beams cannot be directly simulated using the standard Monte Carlo algorithm. Different research groups have developed simulators dealing with some of these problems but the Monte Carlo simulator which considers all of them has not been published yet. Here we present the Monte Carlo program allowing to simulate OCT images of heterogeneous light scattering structures. The presented program considers all of the listed problems and allows to model complex sample geometries with layer boundaries described by a set of polygons. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  • Advancements in Diamond-Like Carbon Coatings
    • Robert Bogdanowicz
    2015

    An essential resource for engineers and scientists in the coatings field, providing an in-depth examination of current and advanced technologies for industrially oriented nanoceramic and nanocomposite coatings

  • Aerodynamic shape optimization by variable-fidelity computational fluid dynamics models: a review of recent progress
    • Leifur Leifsson
    • Sławomir Kozieł
    2015 Journal of Computational Science

    A brief review of some recent variable-fidelity aerodynamic shape optimization methods is presented.We discuss three techniques that—by exploiting information embedded in low-fidelity computationalfluid dynamics (CFD) models—are able to yield a satisfactory design at a low computational cost, usu-ally corresponding to a few evaluations of the original, high-fidelity CFD model to be optimized. Thespecific techniques considered here include multi-level design optimization, space mapping, and shape-preserving response prediction. All of them use the same prediction–correction scheme, however, theydiffer in the way the low-fidelity model information it utilized to construct the surrogate model. Thepresented techniques are illustrated using three specific cases of transonic airfoil design involving liftmaximization and drag minimization.

  • Affective reactions to playing digital games
    • Agnieszka Landowska
    • Michał Wróbel
    2015

    The paper presents a study of emotional states during a gameplay. An experiment of two-player Tetris game is reported, followed by the analysis of the results - self-reported emotional states as well as physiological signals measurements interpretation. The study reveals the diversity of emotional reactions and concludes, that a representative player's emotional model is hard to define. Instead, an adaptive approach to emotion recognition and individualized classifiers seem to be a better solution for affect-aware digital games.