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Gdańsk University of Technology

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Publications from the year 2021

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  • Globalized parametric optimization of microwave components by means of response features and inverse metamodels
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2021 Full text Scientific Reports

    Simulation-based optimization of geometry parameters is an inherent and important stage of microwave design process. To ensure reliability, the optimization process is normally carried out using full-wave electromagnetic (EM) simulation tools, which entails significant computational overhead. This becomes a serious bottleneck especially if global search is required (e.g., design of miniaturized structures, dimension scaling over broad ranges of operating frequencies, multi-modal problems, etc.). In pursuit of mitigating the high-cost issue, this paper proposes a novel algorithmic approach to rapid EM-driven global optimization of microwave components. Our methodology incorporates a response feature technology and inverse regression metamodels to enable fast identification of the promising parameter space regions, as well as to yield a good quality initial design, which only needs to be tuned using local routines. The presented technique is illustrated using three microstrip circuits optimized under challenging scenarios, and demonstrated to exhibit global search capability while maintaining low computational cost of the optimization process of only about one hundred of EM simulations of the structure at hand on the average. The performance is shown to be superior in terms of efficacy over both local algorithms and nature-inspired global methods.

  • Godna praca – koncepcja, pomiar i praktyka w wymiarze rynkowym i organizacyjnym
    • Łukasz Sienkiewicz
    2021

    W opracowaniu przedstawiono koncepcję „godnej pracy”, podejmując próbę analizy definicyjnej tego złożonego pojęcia. Dokonano analizy istniejących podejść, wychodząc od prac Międzynarodowej Organizacji Pracy służących wzmacnianiu godnej pracy w wymiarze globalnym, a także działań podejmowanych na rzecz rozwoju koncepcji „jakości pracy” w wymiarze europejskim. Dokonano przeglądu metod pomiaru godnej pracy oraz pracy wysokiej jakości, w tym stosowanych w tym zakresie mierników i narzędzi pomiarowych. Wskazano również na determinanty godnej pracy w trzech wymiarach: rynkowym, organizacyjnym i indywidualnym. Dokonano przeglądu badań dotyczących godnej pracy przed i po wybuchu pandemii Covid-19.

  • Gossiping by energy-constrained mobile agents in tree networks
    • Jurek Czyzowicz
    • Dariusz Dereniowski
    • Robert Ostrowski
    • Wojciech Rytter
    2021 THEORETICAL COMPUTER SCIENCE

    Every node of an edge-weighted tree network contains a data packet. At some nodes are placed mobile agents, each one possessing an amount of energy (not necessarily the same for all agents). While walking along the network, the agents spend the energy proportionally to the distance traveled and collect copies of the data packets present at the visited network nodes. An agent visiting a node deposits there copies of all currently possessed data packets and collects a copy of every data packet present at this node. Two agents meeting at a node may exchange any amount of currently possessed energy. The gossiping problem asks whether it is possible to achieve that a copy of the original data packet of each node may reach every other node of the network. We prove that the gossiping problem can be solved in time for an n-node tree network T, where k is the number of agents. Moreover, we prove that in order to compute a gossiping strategy, it is enough to start with a minimum-cost convergecast that ends with all data packets and all remaining energy being present at some node of T, and then finish with a minimum-cost broadcast from this configuration. Thus, we obtain two structural properties of the gossiping problem. First, if a gossiping is feasible and r is the first node receiving all information, then there is one that is a concatenation of a convergecast to r and a broadcast from r. Secondly, it is sufficient to consider only optimal convergecast strategies. This is natural to expect but hard to prove, as locations of agents after a convergecast (moved in this stage) are essential. Hence, the convergecast has to be optimal with regards to both spent energy as well as the resulting configuration of agents, which matters in the next stage.

  • „Gra (5)” (Alphago vs Sedol)
    • Krzysztof Wróblewski
    2021

    To już trzydziesta, jubileuszowa edycja przedsięwzięcia organizowanego przez Stowarzyszenie „Wielkie Serce” na rzecz Specjalnego Ośrodka Szkolno-Wychowawczego nr 1 im. J. Matejki w Krakowie. Po raz kolejny, ze względu na pandemię, aukcja zostanie zrealizowana w formule internetowej – finał Aukcji odbędzie się 27 listopada, początek o godz. 16.00. Gospodynią wieczoru będzie Anna Dymna. Zanim jednak odbędzie się sama aukcja, od 13 do 26 listopada w Muzeum Inżynierii Miejskiej trwała wystawa przedaukcyjna. Jednocześnie 13 listopada, o godz. 12.00 za pośrednictwem portalu artinfo.pl rozpoczęła się aukcja internetowa. Przedsięwzięcie po raz kolejny wsparli wybitni twórcy. W tegoroczną jubileuszową edycję aukcji włączyło się blisko dwustu polskich artystów. Podczas aukcji będzie można znaleźć dzieła m.in. takich twórców, jak: Magdalena Abakanowicz, Zdzisław Beksiński, Jan Berdyszak, Rafał Bujnowski, Tadeusz Dominik, Stanisław Dróżdż, Edward Dwurnik, Ryszard Horowitz, Jan Młodożeniec, Jerzy Kałucki, Ewa Kuryluk, Tomasz Kołodziejczyk, The Krasnals, Jarosław Modzelewski, Jan Młodożeniec, Jerzy Nowosielski, Stanisław Rodziński, Franciszek Starowieyski, Wilhelm Sasnal, Marek Sobczyk, Natalia LL, Jan Tarasin, Jerzy Tchórzewski, Ewa Zawadzka. Aukcja to wyjątkowa okazja dla miłośników i kolekcjonerów polskiej sztuki współczesnej. Kolejny raz będzie można obcować z dziełami artystów, którzy tworzą kanon grafiki i malarstwa polskiego, a wybrane prace będą dostępne już od kilkuset złotych.

  • Gradient versus proper gradient homotopies
    • Piotr Bartłomiejczyk
    • Piotr Nowak-Przygodzki
    2021 Homology Homotopy and Applications

    We compare the sets of homotopy classes of gradient and proper gradient vector fields in the plane. Namely, we show that gradient and proper gradient homotopy classi cations are essentially different. We provide a complete description of the sets of homotopy classes of gradient maps from R^n to R^n and proper gradient maps from R^2 to R^2 with the Brouwer degree greater or equal to zero.

  • Grafo-mania, czyli rzecz o grafach i algorytmach. Prawie 300 lat teorii powstałej blisko Gdańska
    • Marek Kubale
    2021 Pismo PG

    W niniejszym numerze inaugurujemy nową kolumnę popularnonaukową w dziale Edukacja. Będzie ona zawierała szkice poświęcone grafom i algorytmom dyskretnym

  • Grafo-mania, czyli rzecz o grafach i algorytmach. Spłaszczanie grafów
    • Marek Kubale
    2021 Pismo PG

    W eseju poruszono problem rysowania grafów na płaszczyźnie.

  • Grafo-mania, czyli rzecz o grafach i algorytmach. Twierdzenie o czterech barwach
    • Marek Kubale
    2021 Pismo PG

    Przedstawiono istotę i historię twierdzenia o 4 barwach.

  • Grafy w Imperium Rzymskim
    • Joanna Raczek
    2021 Full text Pismo PG

    Teoria grafów znalazła zastosowanie w sieciach telekomunikacyjnych, transporcie, bioinformatyce, zarządzaniu i w wielu innych dziedzinach. Ale co ma ona wspólnego z Imperium Rzymskim?

  • Graph Representation Integrating Signals for Emotion Recognition and Analysis
    • Teresa Zawadzka
    • Tomasz Wierciński
    • Grzegorz Meller
    • Mateusz Rock
    • Robert Zwierzycki
    • Michał Wróbel
    2021 Full text SENSORS

    Data reusability is an important feature of current research, just in every field of science. Modern research in Affective Computing, often rely on datasets containing experiments-originated data such as biosignals, video clips, or images. Moreover, conducting experiments with a vast number of participants to build datasets for Affective Computing research is time-consuming and expensive. Therefore, it is extremely important to provide solutions allowing one to (re)use data from a variety of sources, which usually demands data integration. This paper presents the Graph Representation Integrating Signals for Emotion Recognition and Analysis (GRISERA) framework, which provides a persistent model for storing integrated signals and methods for its creation. To the best of our knowledge, this is the first approach in Affective Computing field that addresses the problem of integrating data from multiple experiments, storing it in a consistent way, and providing query patterns for data retrieval. The proposed framework is based on the standardized graph model, which is known to be highly suitable for signal processing purposes. The validation proved that data from the well-known AMIGOS dataset can be stored in the GRISERA framework and later retrieved for training deep learning models. Furthermore, the second case study proved that it is possible to integrate signals from multiple sources (AMIGOS, ASCERTAIN, and DEAP) into GRISERA and retrieve them for further statistical analysis.

  • Graphs hard-to-process for greedy algorithm MIN
    • Marcin Jurkiewicz
    • Krzysztof Pastuszak
    • Mateusz Szypulski
    2021

    We compare results of selected algorithms that approximate the independence number in terms of the quality of constructed solutions. Furthermore, we establish smallest hard- to-process graphs for the greedy algorithm MIN.

  • Green analytical chemistry as an integral part of sustainable education development
    • Justyna Płotka-Wasylka
    • Heba M. Mohamed
    • Aleksandra Kurowska-Susdorf
    • Rajkumar Dewani
    • Michel Y. Fares
    • Vasil Andruch
    2021 Full text Current Opinion in Green and Sustainable Chemistry

    Green chemistry is an important way of thinking in the field of chemistry and aims to conduct processes in accordance with the principles of sustainable development. It is the application of a wide range of principles that minimize the impact of both chemical processes and products on the environment. And what about analytical chemistry? Without a doubt, analytical chemistry plays an important role in the sustainable development of the planet. However, this only applies if analytical procedures are of high quality (sensitive, precise and accurate) and also in line with the principles of environmental sustainability. This essay presents a brief discussion of the evolution of green chemistry and its multidimensional impacts, including the “industry” of analytical chemistry as well as academic education and research. We emphasize the difference between the term “sustainability” and “greenness”. Therefore, at least basic information on sustainability in analytical chemistry is provided. We hope that our considerations will inspire analytical chemists and will contribute to the further development of both green analytical chemistry and sustainable analytical chemistry.

  • Green TPUs from Prepolymer Mixtures Designed by Controlling the Chemical Structure of Flexible Segments
    • Paulina Kasprzyk
    • Ewa Głowińska
    • Paulina Parcheta-Szwindowska
    • Kamila Rohde
    • Janusz Datta
    2021 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    This study concerns green thermoplastic polyurethanes (TPU) obtained by controlling the chemical structure of flexible segments. Two types of bio-based polyether polyols—poly(trimethylene glycol)s—with average molecular weights ca. 1000 and 2700 Da were used (PO3G1000 and PO3G2700, respectively). TPUs were prepared via a two-step method. Hard segments consisted of 4,4?- diphenylmethane diisocyanates and the bio-based 1,4-butanodiol (used as a chain extender and used to control the [NCO]/[OH] molar ratio). The impacts of the structure of flexible segments, the amount of each type of prepolymer, and the [NCO]/[OH] molar ratio on the chemical structure and selected properties of the TPUs were verified. By regulating the number of flexible segments of a given type, different selected properties of TPU materials were obtained. Thermal analysis confirmed the high thermal stability of the prepared materials and revealed that TPUs based on a higher amount of prepolymer synthesized from PO3G2700 have a tendency for cold crystallization. An increase in the amount of PO3G1000 at the flexible segments caused an increase in the tensile strength and decrease in the elongation at break. Melt flow index results demonstrated that the increase in the amount of prepolymer based on PO3G1000 resulted in TPUs favorable in terms of machining.

  • Greencoin: a Pro­environmental Action-­Reward System
    • Kacper Radziszewski
    • Helena Anacka
    • Paweł Weichbroth
    2021 Full text

    The massive destruction of the natural environment is rapidly eroding the world’s capacity to provide food and water, threatening the security of billions of people. In order to facilitate green lifestyles – understood in terms of both pro-environmental behaviors and green self-image on the one hand, and to build sustainable local and global communities, on the other, we put forward an idea of a novel action-reward system based on an application solution, namely Greencoin. In this paper, the framework of the pilot system, underpinning its earnings and value, is introduced. The novelty of the Greencoin system is in introducing an application adjusted to the local needs, that is, based on gamification and aims at encouraging, facilitating and rewarding citizens who undertake pro-environmental actions. In this context, we have formulated and answered two research questions, namely: what practical pro-environmental activities an individual can practice and evidence, as well as what rewards can be offered to an individual for performing such activities in the Greencoin application. To explore these topics, we adopted the literature review (along with the content analysis) method as the methodology for the research. The results concern a broad and multifaceted review of the literature on individual pro-environmental behavior through multiple disciplinary and subject-matter lenses, outlining the corresponding system of rewarding its participants (citizens) with non-monetary and monetary benefits that are to be used in the Greencoin pilot. The study contributes to the topic of smart cities, in particular digital and mobile eco-innovations, resulting in significant progress toward the goal of sustainable development by promoting and facilitating a more efficient and responsible use of natural resources.

  • Greencoin: prototype of a mobile application facilitating and evidencing pro-environmental behavior of citizens
    • Kacper Radziszewski
    • Helena Anacka
    • Hanna Obracht-Prondzyńska
    • Dorota Tomczak
    • Kacper Wereszko
    • Paweł Weichbroth
    2021 Full text

    Among many global challenges, climate change is one of the biggest challenges of our times. While it is one of the most devastating problems humanity has ever faced, one question naturally arises: can individuals make a difference? We believe that everyone can contribute and make a difference to the community and lives of others. However, there is still a lack of effective strategies to promote and facilitate pro-environmental behavior of individuals. To fill this gap, in this paper, we introduce and discuss the Greencoin mobile application prototype. The app is built on existing intelligent data-driven technologies, including supervised and unsupervised learning techniques. Since its end-users will mostly concern the city dwellers, the project falls into the scope of the ongoing research in the area of smart city applications. Nevertheless, the application is still in the design phase, we believe it is a good starting point to spark discussion on its further directions of development, as well as to draw the attention of both national and international audiences to the issues raised.

  • Gronden en afbeeldsels der voornaamste gebouwen, Van alle die Philips Vingboons geordineert heeft
    • Anna Sobolewska
    2021

    Nota katalogowa zawiera informacje nt autora ksiązki, holenderskiego architekta Philipa Vingeboons (1607-1678) i stylu jego zmysłu architektonicznego w projektowaniu amsterdamskich kamienic.

  • Ground Tire Rubber Filled Flexible Polyurethane Foam—Effect of Waste Rubber Treatment on Composite Performance
    • Paulina Kosmela
    • Adam Olszewski
    • Łukasz Zedler
    • Paulina Burger
    • Adam Piasecki
    • Krzysztof Formela
    • Aleksander Hejna
    2021 Full text Materials

    The application range of flexible polyurethane (PU) foams is comprehensive because of their versatility and flexibility in adjusting structure and performance. In addition to the investigations associated with further broadening of their potential properties, researchers are looking for new raw materials, beneficially originated from renewable resources or recycling. A great example of such a material is ground tire rubber (GTR)—the product of the material recycling of post-consumer car tires. To fully exploit the benefits of this material, it should be modified to enhance the interfacial interactions between PU and GTR. In the presented work, GTR particles were thermo-mechanically modified with the addition of fresh and waste rapeseed oil in the reactive extrusion process. The introduction of modified GTR particles into a flexible PU matrix caused a beneficial 17–28% decrease in average cell diameters. Such an effect caused an even 5% drop in thermal conductivity coefficient values, enhancing thermal insulation performance. The application of waste oil resulted in the superior mechanical performance of composites compared to the fresh one and thermo-mechanical modification without oils. The compressive and tensile performance of composites filled with waste oil-modified GTR was almost the same as for the unfilled foam. Moreover, the introduction of ground tire rubber particles enhanced the thermal stability of neat polyurethane foam.

  • Group-9 Transition-Metal Suboxides Adopting the Filled-Ti2Ni Structure: A Class of Superconductors Exhibiting Exceptionally High Upper Critical Fields
    • KeYuan Ma
    • Robin Lefèvre
    • Karolina Górnicka
    • Harald O. Jeschke
    • Xiaofu Zhang
    • Zurab Guguchia
    • Tomasz Klimczuk
    • Fabian O. von Rohr
    2021 CHEMISTRY OF MATERIALS

    Ti2Ni and the related η-carbide structure are known to exhibit various intriguing physical properties. The Ti2Ni structure with the cubic space group Fd3̅m is surprisingly complex, consisting of a unit cell with 96 metal atoms. The related η-carbide compounds correspond to a filled version of the Ti2Ni structure. Here, we report on the structure and superconductivity in the η-carbide-type suboxides Ti4M2O with M = Co, Rh, and Ir. We have successfully synthesized all three compounds in the single-phase form. We found all three compounds to be type-II bulk superconductors with transition temperatures of Tc = 2.7, 2.8, and 5.4 K and with normalized specific heat jumps of ΔC/γTc = 1.65, 1.28, and 1.80 for Ti4Co2O, Ti4Rh2O, and Ti4Ir2O, respectively. We found that all three superconductors exhibit high upper critical fields. Particularly noteworthy in this regard is Ti4Ir2O with an upper critical field of μ0Hc2(0) = 16.06 T, which exceeds by far the weak-coupling Pauli limit─widely considered as the maximal upper critical field─of μ0HPauli = 9.86 T. The role of the void-filling light atom X has so far been uncertain for the overall physical properties of these materials. Herein, we have successfully grown single crystals of Ti2Co. In contrast to the metallic η-carbide-type suboxides Ti4M2O, we found that Ti2Co displays a semimetallic behavior down to 0.75 K. Below 0.75 K, we observe a broad decrease in the resistivity, which can most likely be attributed to an onset of a superconducting transition at lower temperatures. Hence, the octahedral void-filling oxygen plays a crucial role in the overall physical properties, even though its effect on the crystal structure is small. Our results indicate that the design of new superconductors by incorporation of electron–acceptor atoms may in the Ti2Ni-type structures and other materials with crystallographic void position be a promising future approach. The remarkably high upper critical fields, in this family of compounds, may furthermore spark significant future interest.

  • Grywalizacja zajęć akademickich na Politechnice Gdańskiej
    • Joanna Mytnik
    • Brygida Mielewska
    • Aneta Sobiechowska-Ziegert
    • Katarzyna Kubiszewska
    • Natalia Gietka
    2021 Pismo PG

    Jak wyglądają zgrywalizowane zajęcia akademickie na Politechnice Gdańskiej i co sądzą o nich studenci? Zaprezentowano cztery wybrane wdrożenia prototypów zrealizowane w roku akademickim 2020/2021.

  • GTR/NBR/Silica Composites Performance Properties as a Function of Curing System: Sulfur versus Peroxides
    • Łukasz Zedler
    • Xavier Colom
    • Javier Cañavate
    • Krzysztof Formela
    2021 Full text Materials

    In this work, conventional sulfur and two types of organic peroxides (dicumyl peroxide (DCP) and di-(2-tert-butyl-peroxyisopropyl)-benzene (BIB)) curing systems were used to investigate the possibility for tailoring of the performance properties of GTR/NBR blends reinforced with a variable content of highly dispersive silica (0–30 phr). The curing characteristics, static mechanical and acoustical properties, swelling behavior, thermal stability, and microstructure of the prepared composites were investigated. The results show that regardless of the curing system used, increasing the content of highly dispersive silica resulted in the improvement of the mechanical properties of the studied materials. It was observed that sulfur-based systems are the best choice in terms of cross-linking efficiency determined based on torque increment and cross-link density parameters. However, further analysis of the physico-mechanical properties indicated that the cross-linking efficiency does not match the performance of specimens, and the materials obtained using organic peroxides show higher tensile properties. This is due to the improved physical interactions between the GTR/NBR matrix and highly dispersive silica when using peroxide systems. It was confirmed using the analysis of the Wolff activity coefficient, indicating the enhanced synergy.