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Gdańsk University of Technology

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Publications from the year 2020

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  • Realization, programming and controlling of the Stewart-Gough platform
    • Dawid Owoc
    • Krzysztof Ludwiczak
    • Robert Piotrowski
    2020 Full text Journal of Automation, Mobile Robotics and Intelligent Systems - JAMRIS

    This paper presents realizaon, programming, and controlling of a low cost Stewart-Gough plaorm (SGP) with rotary actuators. The realized SGP is applied in a ball & plate control system. Developed dedicated software consists of embedded and applicaon soware for both the SGP posioning system and the ball & plate control. system. A ball posion is being obtained using computer vision. The paper contains tests results for both an SGP posioning accuracy

  • Realizm kapitalistyczny. Czy nie ma alternatywy? / Mark Fisher; przełożył i posłowiem opatrzył Andrzej Karalus
    • Andrzej Karalus
    2020

    Praca rozważa, jak neoliberalna hegemonia instalując „ontologię biznesu” we wszystkich sferach rzeczywistości, formatuje niepostrzeżenie nasze pragnienia, aspiracje i nadzieje. Wbrew triumfalistycznej retoryce „efektywności” i „społecznej odpowiedzialności” realizm kapitalistyczny nie przestaje jednak generować systemowych zaburzeń, które w dłuższej perspektywie go destabilizują. Jest nie tylko przyczyną degradacji środowiska naturalnego i jednym z powodów, dla których mierzymy się z plagą depresji i neuroz, jest również odpowiedzialny za proliferację dużo mniej oczywistych i paradoksalnych zjawisk charakterystycznych dla post-fordowskiej fazy kapitalizmu: rozrostu biurokracji, „PRyzacji” rzeczywistości, sentymentalizacji polityki czy skasowania czasu. Fisher udanie łączy erudycję, zmysł obserwacji, krytyczną przenikliwość oraz wrażliwość na zjawiska i procesy kulturowe, nie uciekając przy okazji od pytań dotyczących kondycji współczesnej lewicy. Jak przełamać monopol realizmu kapitalistycznego i przezwyciężyć rodzące się tendencje autorytarne, nie popadając zarazem w paraliżujący tryb nostalgii i bezproduktywnej tęsknoty za państwem dobrobytu, dawno pogrzebanym światem powojennego konsensusu?

  • Real-Time Volatilomics: A Novel Approach for Analyzing Biological Samples
    • Tomasz Majchrzak
    • Wojciech Wojnowski
    • Małgorzata Rutkowska
    • Andrzej Wasik
    2020 Full text TRENDS IN PLANT SCIENCE

    The use of the ‘omics techniques in environmental research has become common-place. The most widely implemented of these include metabolomics, proteomics, genomics, and transcriptomics. In recent years, a similar approach has also been taken with the analysis of volatiles from biological samples, giving rise to the so-called ‘volatilomics’ in plant analysis. Developments in direct infusion mass spectrometry (DI-MS) techniques have made it possible to monitor the changes in the composition of volatile flux from parts of plants, single specimens, and entire ecosystems in real-time. The application of these techniques enables a unique insight into the dynamic metabolic processes that occur in plants. Here, we provide an overview of the use of DI-MS in real-time volatilomics research involving plants.

  • Recent advances in compatibilization strategies of wood-polymer composites by isocyanates
    • Aleksander Hejna
    • Marta Przybysz-Romatowska
    • Paulina Kosmela
    • Łukasz Zedler
    • Jerzy Korol
    • Krzysztof Formela
    2020 Full text WOOD SCIENCE AND TECHNOLOGY

    Wood-polymer composites technologies are gaining more and more attention in the scientific community, positively affecting the increase in their industrial applications, for example, automotive, building, 3D printing, etc. Many research works are focused on the improvement in matrix–lignocellulosic filler interactions to produce highly filled composites with satisfying performance properties. In this field of research, using isocyanates due to their versatile structure and functionality seems to be a very promising approach. This paper aims at reporting on recent advances in compatibilization strategies of wood-polymer composites by isocyanates. Particular attention is focused on the correlation between isocyanate structure, as well as modification conditions on the matrix–lignocellulosic filler interactions and their impact on the structure–property relationships of wood-polymer composites. Furthermore, limitations and future research trends related to applications of isocyanate to wood-polymer composites technologies are also discussed.

  • Recent advances in high-frequency modeling by means of domain confinement and nested kriging
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2020 Full text IEEE Access

    Development of modern high-frequency components and circuits is heavily based on full-wave electromagnetic (EM) simulation tools. Some phenomena, although important from the point of view of the system performance, e.g., EM cross-coupling effects, feed radiation in antenna arrays, substrate anisotropy, cannot be adequately accounted for using simpler means such as equivalent network representations. Consequently, the involvement of EM analysis, especially for tuning of geometry parameters, has become imperative in high-frequency electronics. Notwithstanding, excessive computational costs associated with massive full-wave simulations required by these procedures and even more by tasks such as uncertainty quantification or multi-criterial optimization, constitute a practical bottleneck. Repetitive evaluations of a structure can be facilitated by the use of fast replacement models (surrogates). Among available methods, approximation models are by far the most popular due to their flexibility and accessibility. Unfortunately, surrogate modeling of high-frequency structures is hindered by the curse of dimensionality and nonlinearity of system responses, primarily frequency characteristics. The recently proposed performance-driven techniques attempt to address this issue by appropriate confinement of the model domain to focus the modeling process only on the relevant part of the parameter space, i.e., containing the designs that are of high quality from the point of view the assumed performance figures. The nested kriging framework is perhaps the most advanced of these methods and allows for constructing reliable surrogates over broad ranges of the system parameters and operating conditions. This article summarizes the recent developments of the technique, including the basic formulation and several advancements aiming at the improvement of the surrogate predictive power or lowering the computational cost of training data acquisition. These include the incorporation of sensitivity data, as well as dimensionality reduction through principal component analysis. The problem of uniform data sampling in confined domains is also discussed. Our considerations are comprehensively illustrated using several examples of antennas and microwave circuits.

  • Recent Advances in Performance-Driven Surrogate Modeling of High-Frequency Structures
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2020 Full text INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS

    Design of high‐frequency structures, including microwave and antenna components, heavily relies on full‐wave electromagnetic (EM) simulation models. Their reliability comes at a price of a considerable computational cost. This may lead to practical issues whenever numerous EM analyses are to be executed, e.g., in the case of parametric optimization. The difficulties entailed by massive simulations may be mitigated by the use of fast surrogates, among which data‐driven models are the most popular ones due to their versatility and accessibility. Unfortunately, conventional modeling techniques are significantly affected by the curse of dimensionality. It is particularly restrictive in the case of high‐frequency components, typically exhibiting highly nonlinear characteristics. Recently, the concept of performance‐driven modeling has been proposed where the surrogate model setup is focused on a small subset of the parameter space, containing the designs that are optimal or nearly optimal with respect to the considered performance figures. Domain confinement allows for a dramatic reduction of the number of training data samples needed for rendering reliable surrogates valid over wide ranges of the system parameters. In this paper, we review some of the recent techniques employing these concepts, discuss their properties, and illustrate them using real‐world examples of antenna and microwave components.

  • Recent advances in traffic optimisation: systematic literature review of modern models, methods and algorithms
    • Aleksander Rydzewski
    • Paweł Czarnul
    2020 IET Intelligent Transport Systems

    Over the past few decades, the increasing number of vehicles and imperfect road traffic management have been sources of congestion in cities and reasons for deteriorating health of its inhabitants. With the help of computer simulations, transport engineers optimise and improve the capacity of city streets. However, with an enormous number of possible simulation types, it is difficult to grasp valuable, innovative solutions which are of the greatest value to city citizens. In this work, the authors expose various problems within this area having reviewed and analysed over 130 papers selected out of 1200 works in the field of urban simulations. The study describes the selection process of important papers and highlights characteristics of microsimulations, macrosimulations, computation optimisations and other approaches found in the literature which are especially useful and should be further built on in the future. They present and compare results provided in reviewed works in terms of throughput improvement, queue, waiting and travel time reduction, vehicle speed increase, speed‐ups as well as assumed simulation parameters. Finally, they focus on research gaps, such as a small number of works considering crisis simulations, few real‐world scale simulations as well as on software architectural changes and low‐level optimizations.

  • Recent progress in the development of steroid sulfatase inhibitors – examples of the novel and most promising compounds from the last decade
    • Mateusz Daśko
    • Sebastian Demkowicz
    • Karol Biernacki
    • Olga Ciupak
    • Witold Kozak
    • Maciej Masłyk
    • Janusz Rachoń
    2020 Full text JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY

    The purpose of this review article is to provide an overview of recent achievements in the synthesis of novel steroid sulfatase (STS) inhibitors. STS is a crucial enzyme in the biosynthesis of active hormones (including estrogens and androgens) and, therefore, represents an extremely attractive molecular target for the development of hormone-dependent cancer therapies. The inhibition of STS may effectively reduce the availability of active hormones for cancer cells, causing a positive therapeutic effect. Herein, we report examples of novel STS inhibitors based on steroidal and nonsteroidal cores that contain various functional groups (e.g., sulfamate and phosphorus moieties) and halogen atoms, which may potentially be used in therapies for hormone-dependent cancers. The presented work also includes examples of multitargeting agents with STS inhibitory activities. Furthermore, the fundamental discoveries in the development of the most promising drug candidates exhibiting STS inhibitory activities are highlighted.

  • Recent total cross section measurements in electron scattering from molecules
    • Czesław Szmytkowski
    • Paweł Możejko
    2020 Full text EUROPEAN PHYSICAL JOURNAL D

    The grand-total cross sections (TCSs) for electron scattering from a range of molecules, measured over the period 2009-2019 in various laboratories, with the use of different electron transmission systems, are reviewed. Where necessary, the presented TCS data are also compared to earlier results. Collection of investigated molecular targets (biomolecules, biofuels, molecules of technological application,hydrocarbons) reflects their current interest in biology, medicine, ecology and industry. Most of measurements covered the energy range from about 1 eV to some hundreds of eV, with a few exceptions extending those limits down to near thermal or up to almost high impact energies. The importance of reliable TCS data in the field of electron-scattering physics is emphasized. Problems encountered in TCS experiments are also specified

  • Reclaimed Rubber/Poly(ε‐caprolactone) Blends: Structure, Mechanical, and Thermal Properties
    • Aleksander Hejna
    • Łukasz Zedler
    • Marta Przybysz-Romatowska
    • Javier Cañavate
    • Xavier Colom
    • Krzysztof Formela
    2020 Full text Polymers

    The amount of elastomeric waste, especially from tires is constantly increasing on a global scale. The recycling of these residua should be considered a priority. Compounding the waste rubbers with other polymers can be an excellent alternative to reuse waste materials. This procedure requires solving the issue of the lack of compatibility between the waste rubber particles and other polymers. Simultaneously, there is a claim for introducing biodegradable plastics materials to reduce their environmental impact. In this work, reclaimed rubber/poly(ε‐caprolactone) (RR/PCL) blends are proposed to enhance the recycling and upcycling possibilities of waste rubbers. The results show that the addition of PCL to the RR allows obtaining blends with improved mechanical properties, good thermal stability, and enhanced interfacial compatibility between the used components. Structure and properties of the proposed RR/PCL have been studied by means of static and dynamic mechanical testing, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA)‐FTIR analysis.

  • Reconfiguring Minimum Dominating Sets in Trees
    • Magdalena Lemańska
    • Paweł Żyliński
    2020 Full text Journal of Graph Algorithms and Applications

    We provide tight bounds on the diameter of γ-graphs, which are reconfiguration graphs of the minimum dominating sets of a graph G. In particular, we prove that for any tree T of order n ≥ 3, the diameter of its γ-graph is at most n/2 in the single vertex replacement adjacency model, whereas in the slide adjacency model, it is at most 2(n − 1)/3. Our proof is constructive, leading to a simple linear-time algorithm for determining the optimal sequence of “moves” between two minimum dominating sets of a tree.

  • Recovery and Management of Postindustrial Spaces in the City on Selected Examples od European Implementations
    • Anna Stasiak
    2020 Full text Przestrzeń i Forma

    Undeveloped, neglected and then abandoned post-industrial areas often located in a short distance from city centers have become, on one hand a major problem for city stewards due to the formation of dead urban tissue disturbing the continuity and cohesion of urbanized areas, on the other hand are spaces with high potential for a good location. The article aims to formulate, from the architectural and urban perspective, an answer to the important question arising in this context: what activities are carried out to recover and properly manage post-industrial spaces?

  • Reduced-Cost Constrained Modeling of Microwave and Antenna Components: Recent Advances
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    • Leifur Leifsson
    2020

    Electromagnetic (EM) simulation models are ubiquitous in the design of microwave and antenna components. EM analysis is reliable but CPU intensive. In particular, multiple simulations entailed by parametric optimization or uncertainty quantification may considerably slow down the design processes. In order to address this problem, it is possible to employ fast metamodels. Here, the popular solution approaches are approximation surrogates, which are versatile and easily accessible. Notwithstanding, the major issue for conventional modeling methods is the curse of dimensionality. In the case of high-frequency components, an added difficulty are highly nonlinear outputs that need to be handled. A recently reported constrained modeling attempts to broaden the applicability of approximation surrogates by confining the surrogate model setup to a small subset of the parameter space. The said region contains the parameter vectors corresponding to high-quality designs w.r.t. the considered figures of interest, which allows for a dramatic reduction of the number of training samples needed to render reliable surrogates without formally restricting the parameter ranges. This paper reviews the recent techniques employing these concepts and provides real-world illustration examples of antenna and microwave structures.

  • Reducing common mode voltage and bearing currents in quasi - resonant DC - link inverter
    • Marek Turzyński
    • Piotr Chrzan
    2020 IEEE TRANSACTIONS ON POWER ELECTRONICS

    In the paper, a concept of separation of an inverter-fed induction motor drive from its mains supply by two transistor switches inserted in the dc-link circuit is reexamined based on the proposed parallel quasi-resonant dc-link inverter (PQRDCLI). The objective of the paper is to show an advantage of the proposed topology in limiting high frequency common mode voltage and bearing currents. In the laboratory setup, an induction machine was equipped with hybrid ceramic bearings and an insulated clutch to measure the shaft-to-frame bearing voltage and the shaft-grounding current. Experimental tests of the PQRDCLI confirm significant reduction of common mode voltage and shaft-to-frame bearing voltage at dc-link zero voltage notches. By controlling the output voltage slopes, the shaft-grounding brush current and the ground leakage current are also reduced. The efficiency measurement and evaluation of the proposed topology, as compared with a two-level hard switched inverter, reveal comparable efficiency of around 95% and indicate loss distributions in both inverters

  • Reduction of the Multipath Propagation Effect in a Hydroacoustic Channel Using Filtration in Cepstrum
    • Agnieszka Czapiewska
    • Andrzej Łuksza
    • Ryszard Studański
    • Andrzej Żak
    2020 Full text SENSORS

    During data transmission in a hydroacoustic channel, one of the problems is the multipath propagation effect, which leads to a decrease in the transmission parameters and sometimes completely prevents it. Therefore, we have attempted to develop a method, which is based on a recorded hydroacoustic signal, that allows us to recreate the original (generated) signal by eliminating the multipath effect. In our method, we use cepstral analysis to eliminate replicas of the generated signal. The method has been tested in simulation and during measurements in a real environment. Additionally, the influence of the method on data transmission in the hydroacoustic channel was tested. The obtained results confirmed the usefulness of the application of the developed method and improved the quality of data transmission by reducing the multipath propagation effect.

  • Refinement of the Hardening Soil model within the small strain range
    • Marcin Cudny
    • Andrzej Truty
    2020 Full text Acta Geotechnica

    The popularity of the elasto-plastic Hardening Soil (HS) model is based on simple parameter identification from standard testing and empirical formulas. The HS model is implemented in many commercial FE codes designed to analyse geotechnical problems. In its basic version, the stress–strain behaviour within the elastic range is subject to the hypoelastic power law, which assures the barotropy of the elastic stiffness. However, a proper modelling within the small strain range, i.e. strain-induced stiffness degradation and correct reproduction of the hysteretic behaviour, was one of the most important drawbacks in the HS formulation. The first small strain stiffness extension to the HS model was proposed by Benz (Small strain stiffness of soils and its numerical consequences, 2007), and the new model was called Hardening Soil Small (HSS). Despite the simple isotropic formulation, its applicability was proved in various numerical simulations in geotechnics. However, the HSS formulation exhibits a serious fault known in the literature as overshooting, i.e. uncontrolled reset of the loading memory after tiny unloading–reloading cycles. The authors’ main aim was to retain the set of material parameters for the HSS formulation and to propose a new small strain extension to the HS model without overshooting. The new proposal is based on the BRICK model which represents the concept of nested yield surfaces in strain space. The implementation aspects of the new HS-Brick model are described, and its performance is presented in some element tests and selected boundary value problems by comparisons with the HSS formulation.

  • Regulacja napięcia w sieci nN z rozproszonymi źródłami energii
    • Zbigniew Krzemiński
    2020 Full text Przegląd Elektrotechniczny

    Podłączanie rozproszonych źródeł energii do sieci energetycznych niskiego napięcia powoduje powstawanie problemów zmienności i niesymetrii napięcia, zwłaszcza w przypadku dużych odległości od transformatora zasilającego. W skrajnych przypadkach zachodzi konieczność redukcji mocy generowanej przez źródło podczas oddawaniu energii do sieci. Rozwiązaniem tego problemu jest zastosowanie energoelektronicznego regulatora napięcia składającego się z dwóch falowników, z których jeden służy do dodawania, za pomocą transformatora dodawczego, napięcia o regulowanej małej amplitudzie. Drugi falownik służy do dostarczania energii czynnej do układu regulacji oraz do korekty poboru mocy biernej w założonym zakresie. W referacie pokazano zastosowanie regulatora do stabilizacji napięcia sieci nN z generacją rozproszoną.

  • Regularity of weak solutions for aclass of elliptic PDEs in Orlicz-Sobolev spaces
    • Jakub Maksymiuk
    • Karol Wroński
    2020 Full text Topological Methods in Nonlinear Analysis

    We consider the elliptic partial differential equation in the divergence form $$-\div(\nabla G(\nabla u(x))) t + F_u (x, u(x)) = 0,$$ where $G$ is a convex, anisotropic function satisfying certain growth and ellipticity conditions We prove that weak solutions in $W^{1,G}$ are in fact of class $W^{2,2}_{loc}\cap W^{1,\infty}_{loc}$.

  • Regulation of the First Committed Step in Lipopolysaccharide Biosynthesis Catalyzed by LpxC Requires the Essential Protein LapC (YejM) and HslVU Protease
    • Daria Biernacka
    • Patrycja Gorzelak
    • Gracjana Klein-Raina
    • Satish Raina
    2020 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    We previously showed that lipopolysaccharide (LPS) assembly requires the essential LapB protein to regulate FtsH-mediated proteolysis of LpxC protein that catalyzes the first committed step in the LPS synthesis. To further understand the essential function of LapB and its role in LpxC turnover, multicopy suppressors of ΔlapB revealed that overproduction of HslV protease subunit prevents its lethality by proteolytic degradation of LpxC, providing the first alternative pathway of LpxC degradation. Isolation and characterization of an extragenic suppressor mutation that prevents lethality of ΔlapB by restoration of normal LPS synthesis identified a frame-shift mutation after 377 aa in the essential gene designated lapC, suggesting LapB and LapC act antagonistically. The same lapC gene was identified during selection for mutations that induce transcription from LPS defects-responsive rpoEP3 promoter, confer sensitivity to LpxC inhibitor CHIR090 and a temperature-sensitive phenotype. Suppressors of lapC mutants that restored growth at elevated temperatures mapped to lapA/lapB, lpxC and ftsH genes. Such suppressor mutations restored normal levels of LPS and prevented proteolysis of LpxC in lapC mutants. Interestingly, a lapC deletion could be constructed in strains either overproducing LpxC or in the absence of LapB, revealing that FtsH, LapB and LapC together regulate LPS synthesis by controlling LpxC amounts.

  • Reinforced Secure Gossiping Against DoS Attacks in Post-Disaster Scenarios
    • Christian Esposito
    • Zhongliang Zhao
    • Jacek Rak
    2020 Full text IEEE Access

    During and after a disaster, the perceived quality of communication networks often becomes remarkably degraded with an increased ratio of packet losses due to physical damages of the networking equipment, disturbance to the radio frequency signals, continuous reconfiguration of the routing tables, or sudden spikes of the network traffic, e.g., caused by the increased user activity in a post-disaster period. Several techniques have been introduced so far (mainly using data retransmission mechanisms) to tolerate such circumstances. Among them, gossiping has been shown to be efficient in the recovery from message losses. However, a conventional gossiping scheme may exhibit security problems, which can be exploited for further attacks (such as Denial of Service – DoS attack). For instance, the flooding method used by the gossiping can be used to forward the traffic towards many vulnerable nodes to drain their resources and compromise them. Typically, protection against DoS attacks is realized by using cryptographic primitives. However, their scalability limits and costs make them improper for emergency communications after a disaster. In this article, we introduce an approach based on reinforcement learning and game theory to protect the gossiping scheme from DoS attacks without incurring the costs of cryptographic primitives. In our method, nodes properly select which requests to satisfy, which in turn helps other nodes to avoid receiving manipulated gossip messages from malicious and colluded nodes. Additionally, our method operates without exploiting any cryptographic primitives, which prevents excessive energy waste that is undesired in post-disaster resilient networking. Simulation experiments performed in OMNeT++ confirmed the advantages of our approach over the reference schemes in terms of reliability, security, overhead, latency, and power efficiency.