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Gdańsk University of Technology

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Publications from the year 2018

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  • Tome-lapse X-ray tomography imaging of flow patterns in versatile silo model
    • Laurent Babout
    • Krzysztof Grudzień
    • Selam Waktola
    • Maciej Niedostatkiewicz
    • Adrien Jerome
    • Maire Eric
    2018

    The paper introduces a new versatile silo model that was especially designed for in situ X-ray tomography studies of silo discharge for various flow conditions, namely concentric and eccentric. The presented work focuses on organic granular materials where low fraction of short-grain white rice is mixed with spheroidal sorghum particles. The high-quality tomography images combined with adequate image processing strategy allows to unambiguously analyze individual grains dynamic behavior during silo discharge. The quantitative image analysis also reveals granular compaction rates in different zones of the funnel flow, which are in agreement with the literature. The proposed experimental methodology is proven to be solid enough to investigate in more details dynamic phenomena during silo discharge. It can also serve as a strong baseline for numerical calibration and predications.

  • Topological modifications for performance improvement and size reduction of wideband antenna structures
    • Adrian Bekasiewicz
    • Sławomir Kozieł
    2018 Full text

    Compact antennas belong to the key components of modern communication systems. Their miniaturization is often achieved by introducing appropriate topological changes such as simple ground plane slots or tapered feeds. More sophisticated modifications are rarely considered in the literature because they normally lead to significant increase of the number of tunable parameters, which makes the antenna design process more challenging. On the other hand, complex topological changes are questionable as their effects on radiator performance and/or size reduction are difficult to be verified in practice. In particular, parameter sweeping commonly used for dimension adjustment is incapable of their appropriate handling. In this work, the effect of feed line and ground plane modifications on performance and size reduction of a wideband antenna is investigated. Considered geometrical changes include a ground plane slot and a stepped impedance feed line (both with gradually increasing number of sections). The modified structures have been optimized for minimum in-band reflection and minimum size using a robust gradient-based algorithm. The obtained results demonstrate that complex topological modifications may be useful for achieving both good performance and small size when handled comprehensively.

  • Torsional buckling and post-buckling of columns made of aluminium alloy
    • Czesław Szymczak
    • Marcin Kujawa
    2018 Full text APPLIED MATHEMATICAL MODELLING

    The paper concerns torsional buckling and the initial post-buckling of axially compressed thin-walled aluminium alloy columns with bisymmetrical cross-section. It is assumed that the column material behaviour is described by the Ramberg–Osgood constitutive equation in non-linear elastic range. The stationary total energy principle is used to derive the governing non-linear differential equation. An approximate solution of the equation determined by means of the perturbation approach allows to determine the buckling loads and the initial post-buckling behaviour. Numerical examples dealing with simply supported I-column are presented and the effect of material elastic non-linearity on the critical loads and initial post-buckling behaviour are compared to the linear solution.

  • Total domination in versus paired-domination in regular graphs
    • Joanna Cyman
    • Magda Dettlaff
    • Michael A. Henning
    • Magdalena Lemańska
    • Joanna Raczek
    2018 Full text Discussiones Mathematicae Graph Theory

    A subset S of vertices of a graph G is a dominating set of G if every vertex not in S has a neighbor in S, while S is a total dominating set of G if every vertex has a neighbor in S. If S is a dominating set with the additional property that the subgraph induced by S contains a perfect matching, then S is a paired-dominating set. The domination number, denoted γ(G), is the minimum cardinality of a dominating set of G, while the minimum cardinalities of a total dominating set and paired-dominating set are the total domination number, \gt(G), and the paired-domination number, \gp(G), respectively. For k ≥ 2, let G be a connected k-regular graph. It is known [Schaudt, Total domination versus paired domination, Discuss. Math. Graph Theory 32 (2012) 435--447] that \gpr(G)/γt(G) \le (2 k)/(k + 1). In the special case when k = 2, we observe that \gpr(G)/γt(G) \le 4/3, with equality if and only if G \cong C5. When k = 3, we show that \gpr(G)/γt(G) \le 3/2, with equality if and only if G is the Petersen graph. More generally for k ≥ 2, if G has girth at least 5 and satisfies \gpr(G)/γt(G) = (2 k)/(k + 1), then we show that G is a diameter-2 Moore graph. As a consequence of this result, we prove that for k ≥ 2 and k \ne 57, if G has girth at least 5, then \gpr(G)/γt(G) \le (2 k)/(k + 1), with equality if and only if k=2 and G \cong C5 or k = 3 and G is the Petersen graph.

  • Total Domination Versus Domination in Cubic Graphs
    • Joanna Cyman
    • Magda Dettlaff
    • Michael A. Henning
    • Magdalena Lemańska
    • Joanna Raczek
    2018 Full text GRAPHS AND COMBINATORICS

    A dominating set in a graph G is a set S of vertices of G such that every vertex not in S has a neighbor in S. Further, if every vertex of G has a neighbor in S, then S is a total dominating set of G. The domination number,γ(G), and total domination number, γ_t(G), are the minimum cardinalities of a dominating set and total dominating set, respectively, in G. The upper domination number, \Gamma(G), and the upper total domination number, \Gamma_t(G), are the maximum cardinalities of a minimal dominating set and total dominating set, respectively, in G. It is known that γ_t(G)/γ (G)≤2 and \Gamma_t(G)/ \Gamma(G)≤2 for all graphs G with no isolated vertex. In this paper we characterize the connected cubic graphs G satisfying γ_t(G)/γ (G)=2, and we characterize the connected cubic graphs G satisfying \Gamma_t(G)/ \Gamma(G)=2.

  • Toughness augmentation by fibrillation and yielding in nanostructured blends with recycled polyurethane as a modifier
    • Arunima Reghunadhan
    • Janusz Datta
    • Nandakumar Kalarikkal
    • Józef Haponiuk
    • Sabu Thomas
    2018 APPLIED SURFACE SCIENCE

    In the present paper, we have carefully investigated the morphology and fracture mechanism of the recycled polyurethane (RPU) /epoxy blend system. The second phase (RPU) added to the epoxy resin has a positive effect on the overall mechanical properties. Interestingly, the recycled polymer has a remarkable effect on the fracture toughness of epoxy resin. The mechanism behind the fracture toughness improvement up on the addition of RPU was found to be very similar to that of the incorporation of hyperbranched polymers in epoxy resin. Brittle to ductile fracture was clear in the case of higher loadings such as 20 and 40 phr of RPU in the epoxy resin. The mechanism behind improvement of fracture toughness was found to fibrillation of the RPU phase which was evidenced by the fracture morphology. In fact the force applied to the epoxy matrix was effectively transferred to the added RPU phase due to its strong interaction with the epoxy phase. This effective transfer of force to the RPU phase protects the epoxy matrix without catastrophic failure and we observed 44% increase in G1C values at an addition of 40 phr RPU. This results in the extensive fibrillation of RPU which causes the generation of new surfaces. Thus the impact energy has been fully utilized by the RPU phase. The mechanism is termed as simultaneous reinforcing and toughening and normally reported as a result of cavitations and yielding. SEM, HRTEM and AFM analyses clearly demonstrated the fibrillated morphology of the fracture surface and the formation of nanostructures. This report is first of its kind in the case of both epoxy modification and the elastomer toughening.

  • Toward Intelligent Vehicle Intrusion Detection Using the Neural Knowledge DNA
    • Fei Li
    • Haoxi Zhang
    • Juan Wang
    • Cesar Sanin
    • Edward Szczerbicki
    2018 Full text CYBERNETICS AND SYSTEMS

    In this paper, we propose a novel intrusion detection approach using past driving experience and the neural knowledge DNA for in-vehicle information system security. The neural knowledge DNA is a novel knowledge representation method designed to support discovering, storing, reusing, improving, and sharing knowledge among machines and computing systems. We examine our approach for classifying malicious vehicle control commands based on learning from past valid driving behavior data on a simulator.

  • Towards a method for detecting large roll motions suitable for oceangoing ships
    • Maria Acanfora
    • Przemysław Krata
    • Jakub Montewka
    • Pentti Kujala
    2018 APPLIED OCEAN RESEARCH

    The concept of autonomous merchant ships is quite recent. The increasing interest in autonomous vessels is nowadays calling for smart technologies that are supposed to replace the human actions on board. This involves troublesome issues related to ship safety. In the future, decision-making processes that are conventionally performed by human beings on board ship will be moved ashore to the control centre and maybe even completely replaced by computers and smart technologies. This paper proposes a method suitable for oceangoing ships, providing an autonomous routine for the avoidance of two dangerous phenomena involving excessive motions of the ship, e.g. the synchronous roll and the parametric resonance, both taking place in rough seas. The method is two-fold, since it pertains to the process of route planning and route monitoring and it encompasses two submethods (A and B). Submethod A is used to define a set of operational scenarios to be avoided due to excessive accelerations, with the use of a numerical ship motion model. This is applied at the route-planning stage. Submethod B is developed to monitor ship motions and to detect large roll motion for a ship in the seaway. It also raises alerts at two levels, first when the large roll motions are expected to develop (leaving ample time for remotely located operators to react), second when the large roll motions are developing (leaving a short time window for action taken on board the ship). The main sources of uncertainty are defined and the solutions to address those are proposed. Finally, the method is applied on simulated time histories of ship motion, which is a container ship traversing the Pacific Ocean. The obtained results are promising; however, further work is required with respect to various manoeuvers performed by a ship in the seaway.

  • Towards Audio Signal Equalization Based on Spectral Characteristics of a Listening Room and Music Content Reproduced
    • Piotr Hoffmann
    • Bożena Kostek
    2018

    This study presents investigations of the influence of the room acoustics on the frequency characteristic of the audio signal playback. First, the concept of a novel spectral equalization method of the room acoustic conditions is introduced. On the basis of the room spectral response, a system for room acoustics compensation based on an equalizer designed is proposed. The system settings depend on music genre recognized automatically. In order to acquire room acoustic characteristics, a series of measurements are performed. The impact of the enclosure on particular music genre spectral characteristics has also been presented. In the analyses a comparison of spectral characteristics obtained with pink noise and music genres as measurement signals is presented.

  • Towards Contactless, Hand Gestures-Based Control of Devices
    • Krzysztof Czuszyński
    • Jacek Rumiński
    2018

    Gesture-based intuitive interactions with electronic devices can be an important part of smart home systems. In this paper, we adapt the contactless linear gesture sensor for the navigation of smart lighting system. Set of handled gestures allow to propose two methods of active light source selection, continuous dimming, and turning on and off based on discrete gestures. The average gesture recognition accuracy was 97.58% in the first of proposed methods of lamp selection and 95.45% in the second method. Apart of the accuracy of the gesture sensor in the real case implementation the user convenience of navigation was monitored. 72.73% of users pointed the first method as more intuitive and convenient to use. 63.64% of users indicated that the dimming of light is more intuitive when moving a hand along the sensor than closing it towards the package. The impact of utilizing dirty or gloved hand on the pose recognition accuracy of the sensor was verified as well. The results indicate the capability of incorporating considered touchless gesture sensor to homes, factories or operating rooms. These are places where the need of the functionality of discrete and continuous gestures for handling some basic devices or functions can be limited due to dirty hand scenarios or sterility requirements.

  • Towards high quality ITO coatings: the impact of nitrogen admixture in HiPIMS discharges
    • Vitezslav Stranak
    • Robert Bogdanowicz
    • Petr Sezemsky
    • Harm Wulff
    • Angela Kruth
    • Mateusz Smietana
    • Jiri Kratochvil
    • Martin Cada
    • Zdenek Hubicka
    2018 SURFACE & COATINGS TECHNOLOGY

    The paper reports controlled deposition of optically transparent and electrically conductive ITO films prepared by a combination of rf (13.56 MHz) and High Power Impulse Magnetron Sputtering (HiPIMS) systems without any post deposition thermal treatment/annealing. It is shown that (i) reactive admixture of N2 gas to the process and (ii) pressure in the deposition chamber enable to optimize optical properties of ITO films. Furthermore, the changes of electrical resistivity were observed, too. The variation of these ITO properties are attributed to change of crystalline structure measured by XRD methods.

  • Towards New Mappings between Emotion Representation Models
    • Agnieszka Landowska
    2018 Full text Applied Sciences-Basel

    There are several models for representing emotions in affect-aware applications, and available emotion recognition solutions provide results using diverse emotion models. As multimodal fusion is beneficial in terms of both accuracy and reliability of emotion recognition, one of the challenges is mapping between the models of affect representation. This paper addresses this issue by: proposing a procedure to elaborate new mappings, recommending a set of metrics for evaluation of the mapping accuracy, and delivering new mapping matrices for estimating the dimensions of a Pleasure-Arousal-Dominance model from Ekman’s six basic emotions. The results are based on an analysis using three datasets that were constructed based on affect-annotated lexicons. The new mappings were obtained with linear regression learning methods. The proposed mappings showed better results on the datasets in comparison with the state-of-the-art matrix. The procedure, as well as the proposed metrics, might be used, not only in evaluation of the mappings between representation models, but also in comparison of emotion recognition and annotation results. Moreover, the datasets are published along with the paper and new mappings might be created and evaluated using the proposed methods. The study results might be interesting for both researchers and developers, who aim to extend their software solutions with affect recognition techniques.

  • Towards Understanding of Mechanics of Hernia Managed by Synthetic Mesh in Laparoscopic Operation: A Single Case Study
    • Agnieszka Tomaszewska
    • Izabela Lubowiecka
    • Czesław Szymczak
    2018 Advances in Intelligent Systems and Computing

    In this paper a research towards understanding of mechanics of ventral hernia operated with the use of Physiomesh Open image in new window implant and SecureStrap Open image in new window staples is described. Experimental and numerical studies are conducted for that purpose. Experimental works cover uni-axial tension tests of the implant samples and of the implant-staples-tissue system. Also experiments on implant-staples-tissue models, representing operated hernia, subjected to impulse pressure loading are performed. Based on that, constitutive model of the mesh has been identified and failure load of the staples has been determined. In the experiments on the operated hernia systems subjected to pressure loading safe loading level has been determined and failure modes connected to higher pressure values have been observed. Finally, in the numerical simulations of the operated hernia model, built according to FEM rules, it has been proved that failures observed experimentally result from exceeding of the load bearing capacity of the staples considered in this study.

  • Tożsamość i przynależność do miasta w dobie globalizacji
    • Małgorzata Dymnicka
    • Paweł Starosta
    2018 Full text Miscellanea Anthropologica et Sociologica

    Celem naszej wypowiedzi jest próba przedstawienia wybranych koncepcji przynależności i tożsamości w miastach doby globalizacji. We współczesnej socjologii, zwłaszcza w tych jej odmianach, które zajmują się problematyką miejską, można odnaleźć wiele istotnych ustaleń wspierających tezę, że istotę procesu globalizacji stanowi odprzestrzennienie relacji gospodarczych, społecznych i kulturowych. Globalizacja działa aktywnie również na polu kultury miejskiej, obejmując swoim zakresem tożsamości, sposoby życia, zjawisko kulturowej różnorodności i hybrydyzacji. Tożsamości miejskie częściej niż kiedykolwiek stają się przedmiotem negocjacji tego, co lokalne, z tym, co kosmopolityczne. Przynależność do miejsca z kolei to idealna sytuacja dla „nowych plemion”, czyli wspólnot tworzących się wokół podzielanych zainteresowań, przekraczających granice klasowe, geograficzne, wiekowe, kulturowe etc. Wyzwaniem dla współczesności staje się akceptacja wielu „wiosek” dających poczucie zakorzenienia i przynależności.

  • Trace Elements in Aquatic Environments
    • Piotr Konieczka
    • Bartłomiej Cieślik
    • Jacek Namieśnik
    2018

    A trace element is defined as a chemical element whose the average concentration is less than 100 ppm (mg/kg, mg/L – in the case of a water matrix). In aquatic environments the concentrations of trace elements are usually at the level of picomoles per liter and lower. This causes extreme analytical problems, especially in situations where low content is in the range of background levels. Taking into account the role of trace elements in the environment, there are toxic ones, physiological, and inert.

  • Tracing financial innovation diffusion and substitution trajectories. Recent evidence on exchange-traded funds in Japan and South Korea.
    • Ewa Lechman
    • Adam Marszk
    2018 Full text TECHNOLOGICAL FORECASTING AND SOCIAL CHANGE

    Since the rapid growth of the popularity of ETFs, the potential substitution between innovative financial products, exchange-traded funds (ETFs), and traditional investment funds (open-end and closed-end funds) is recognized as one of the most-discussed issues in the financial industry. This is the first study to empirically verify and compare the diffusion and substitution of ETFs using monthly data on their assets in two selected countries. The main aim of this paper is to provide in-depth insights into the development of innovative financial products available in two Asian economies: Japan and South Korea. The empirical study uses monthly total net assets data for 2004–2017. Our methodological framework combines models of innovation diffusion and technological substitution. The results reported in the study show that in both countries the diffusion of ETFs has occurred. The rate of diffusion and the phase of growth reached differed – in Japan the ETF market was in the early exponential growth stage, whereas in South Korea it was closer to achieving the expected maximum saturation. The results of the substitution analysis between the largest category of the innovative funds – equity ETFs and equity open-end funds clearly demonstrate that the process of “switching” from equity open-end funds into ETFs may be easily traced in both countries. Substitution processes were, however, gradual and reversals of the trajectories were noticed

  • Trade-offs in multiparty Bell-inequality violations in qubit networks
    • Ravishankar Ramanathan
    • Piotr Andrzej Mironowicz
    2018 Full text PHYSICAL REVIEW A

    Two overlapping bipartite binary input Bell inequalities cannot be simultaneously violated as this would contradict the usual no-signalling principle. This property is known as monogamy of Bell inequality violations and generally Bell monogamy relations refer to trade-offs between simultaneous violations of multiple inequalities. It turns out that multipartite Bell inequalities admit weaker forms of monogamies that allow for violations of a few inequalities at once. Here we systematically study monogamy relations between correlation Bell inequalities both within quantum theory and under the sole assumption of no signalling. We first investigate the trade-offs in Bell violations arising from the uncertainty relation for complementary binary observables, and exhibit several network configurations in which a tight trade-off arises in this fashion. We then derive a tight trade-off relation which cannot be obtained from the uncertainty relation showing that it does not capture monogamy entirely. The results are extended to Bell inequalities involving different number of parties and find applications in device-independent secret sharing and device-independent randomness extraction. Although two multipartite Bell inequalities may be violated simultaneously, we show that genuine multi-party non-locality, as evidenced by a generalised Svetlichny inequality, does exhibit monogamy property. Finally, using the relations derived we reveal the existence of flat regions in the set of quantum correlations.

  • Traffic Remapping Attacks in Ad Hoc Networks
    • Jerzy Konorski
    • Szymon Szott
    2018 Full text IEEE COMMUNICATIONS MAGAZINE

    Ad hoc networks rely on the mutual cooperation of stations. As such, they are susceptible to selfish attacks that abuse network mechanisms. Class-based QoS provisioning mechanisms, such as the EDCA function of IEEE 802.11, are particularly prone to traffic remapping attacks, which may bring an attacker better QoS without exposing it to easy detection. Such attacks have been studied in wireless LANs, whereas their impact in multihop settings is less known. We provide a definition of traffic remapping attacks, highlighting their ease of execution, and analyze their impact in multihop networks. Suitable detection methods and defense measures are also discussed and evaluated.

  • Train the trainer course
    • Marzena Grzesiak
    • Magdalena Olczyk
    2018

    This chapter presents the concept, evaluation and evaluation results for the train the trainer. This concept of train the trainers is prepared within Workpackage 5 of EU-funded project: MASTER BSR (Erasmus+ Strategic Partnership Programme). Due to the nature of adult learning the content is designed for the use of participatory methods (involved, active). This method uses various techniques of active learning e.g. group work, simulation or discussion. The main purpose of ‘train the trainer’ is to transfer knowledge, develop skills and competences, build up engaged attitudes among lecturers and teachers who train the craftsmen and skilled workers to master craftsmen. The target group of “train the trainer” are teachers, lecturers and instructors that train craftsmen and skilled workers for master craftsman. In the “train the trainer” seminar they should obtain additional competences. Evaluation of training concerning both quality and knowledge increase. The generic goal of most evaluations is to provide "useful feedback" to a variety of audiences including sponsors, donors, client-groups, administrators, staff, and other relevant constituencies. Most often, feedback is perceived as "useful" if it aids in decision-making. But the relationship between an evaluation and its impact is not a simple one - studies that seem critical sometimes fail to influence short-term decisions, and studies that initially seem to have no influence can have a delayed impact when more congenial conditions arise. Despite this, there is broad consensus that the major goal of evaluation should be to influence decision-making or policy formulation through the provision of empirically-driven feedback. The aim of the train the trainers evaluation is to improve training design, content and delivery. First, we want to evaluate the trainees and their reaction during training delivery. Second, the trainer work will be evaluated. Evaluation results allowed for the formulation of guidelines for improving the training.

  • Transcriptional profile of in vitro expanded human epidermal progenitor cells for the treatment of non-healing wounds
    • Paulina Langa
    • Anna Wardowska
    • Jacek Zieliński
    • Justyna Podolak-Popinigis
    • Piotr Sass
    • Paweł Sosnowski
    • Karolina Kondej
    • Alicja Renkielska
    • Paweł Sachadyn
    • Piotr Trzonkowski
    • Michał Pikuła
    2018 JOURNAL OF DERMATOLOGICAL SCIENCE

    Background Epidermal progenitor cells (EPCs) have been under extensive investigation due to their increasing potential of application in medicine and biotechnology. Cultured human EPCs are used in the treatment of chronic wounds and have recently became a target for gene therapy and toxicological studies. One of the challenges in EPCs culture is to provide a high number of undifferentiated, progenitor cells displaying high viability and significant biological activity. Objectives The goal of this study was to characterize the in vitro cultured progenitor cells and the assessment whether the cells with the progenitor phenotype are able to enhance wound healing. Additionally, we aimed to estab lish the complete procedure of the culture, analysis and clinical application of epidermal progenitor cells. Methods In this study we present a method of cell isolation and culture followed by a technique of transplantation of the cultured cells onto the wound bed. The applied isolation technique involves two enzymatic steps (dispase, trypsin) and it is characterized with a high yield of cells. The obtained cells were cultured in vitro up to the second passage in serum-free and xeno-free keratinocytes-dedicated medium. Key stem cell markers were determined with means of flow cytometry and quantitative real-time PCR. Results The in vitro expanded cells displayed high proliferative activity without features of either apoptosis or necrosis. The flow cytometry and transcriptomic analyses showed the enhanced expression of stem cell mark ers (i.e. ΔNp63, CD29, CD49f and BNC1, CDKN1A transcripts) in the expanded cells. In the presented com passionate use study, cultured autologous cells from an oncological patient were suspended in fibrin sealant and transplanted directly to a non-healing wound, resulting in wound closure within 2 months. Conclusion The cells cultured in serum-free media display epidermal stem cells features and a potential to stimulate wound healing. This promising procedure of isolation, culture and application warrants further clinical trials in the treatment of chronic wounds.