2021 - Repozytorium publikacji - Politechnika Gdańska

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Bistability in a One-Dimensional Model of a Two-Predators-One-Prey Population Dynamics System
- Sergey Kryzhevich
- Viktor Avrutin
- Gunnar Sӧderbacka
2021 Pełny tekst Lobachevskii Journal of Mathematics
In this paper, we study a classical two-predators-one-prey model. The classical model described by a system of three ordinary differential equations can be reduced to a one-dimensional bimodalmap. We prove that this map has at most two stable periodic orbits. Besides, we describe the bifurcation structure of the map. Finally, we describe a mechanism that leads to bistable regimes. Taking this mechanism into account, one can easily detect parameter regions where cycles with arbitrary high periods or chaotic attractors with arbitrary high numbers of bands coexist pairwise.
Block graphs with large paired domination multisubdivision number
- Christina M. Mynhardt
- Joanna Raczek
2021 Pełny tekst Discussiones Mathematicae Graph Theory
The paired domination multisubdivision number of a nonempty graph G, denoted by msdpr(G), is the smallest positive integer k such that there exists an edge which must be subdivided k times to increase the paired domination number of G. It is known that msdpr(G) ≤ 4 for all graphs G. We characterize block graphs with msdpr(G) = 4.
Blockchain technologies to address smart city and society challenges
- Julian Szymański
- Higinio Mora
- Julio Mendoza-Tello
- Erick Varela-guzmán
2021 COMPUTERS IN HUMAN BEHAVIOR
New Information and Communications Technologies (ICT) are changing the way in which the world works. These technologies provide new tools to face the issues of contemporary society (poverty, migrations, sustainable development challenges, governance, etc.). Among them, blockchain emerge as a disruptive technology able to make things in a completely different and innovative way. They can provide solutions where before there were none. Recently, these technologies have become subject of intense research and development by industry and academia. In consequence, a large amount of interesting works is published in many areas, proposing solutions, services, frameworks and applications based on these technologies. The research focusing on the previous challenges are especially interesting in current society. However, the proposals arrive at higher speed than society can assimilate them, and sometimes they are not properly exploited. Thus, this paper provides a comprehensive overview of the blockchain technology to identify what are its key attributes that enable to successfully address the social challenges. The review has been conducted from three point of views: service-delivery, resource-management and city-administration, and has been focused on the Sustainable Development Goals of the United Nations, in order to cover the full agenda of current social issues. The contributions of this work are an exhaustive compilation of the existing research on blockchain technology to tackle the social challenges from several angles, and the identification of the key features and the conditioning factors of the practical applicability of the technology.
Blockchain: zdecentralizowane zaufanie
- Stanisław Barański
2021
Bitcoin wprowadził innowację na wielu płaszczyznach. Jako pierwszy rozwiązał problem osiągania konsensusu w sieciach otwartych, stworzył zagadkę ekonomiczną w postaci globalnej waluty deflacyjnej, pozwolił na transfer pieniędzy tym, którzy wcześniej byli wykluczeni bankowo, ale przede wszystkim stworzył fundamenty pod platformę zdecentralizowanego zaufania. Zapoczątkował technologie zdecentralizowanych aplikacji, które dotychczas nie mogły istnieć bez zaufanej trzeciej strony. W pracy opisana została ta ostatnia płaszczyzna.
Błedy realizacji prac remontowych przyczyną uszkodzeń wilgotnościowych zabytkowego budynku sali BHP w Gdańsku
- Maciej Niedostatkiewicz
2021 Pełny tekst Builder
W artykule przedstawiono opis uszkodzeń wilgotnościowych występujących w historycznym budynku sali VBHP w Gdańsku po zakończeniu prac związanych z jego remonem opraz opisano zakres podjętych prac naprawczych
Book Review
- Edward Szczerbicki
2021 Intelligent Decision Technologies-Netherlands
Acting over the last three decades as an Editor and Associate Editor for a number of international journals in the general area of cybernetics and AI, as well as a Chair and Co-Chair of numerous conferences in this field, I have had the exciting opportunity to closely witness and to be actively engaged in the stimulating research area of machine learning and its important augmentation with deep learning techniques and technologies. From this extensive personal perspective of an active researcher, I consider the book “Machine Learning Paradigms: Advances in Deep Learning-based Technological Applications” a very important and truly outstanding contribution into the enhancement of our understanding of how deep learning can be applied in real life centred technologies and techniques within a number of important and truly diverse domains. These domains include medical, geospatial, social, economic, and food processing just to mention a few that are covered in this significant book. Its 16 chapters are all well presented, coherent, and well written. The presented applications are innovative and supported by scientifically rigorous research. I find it remarkable that the Editors were able to complete such a comprehensive compendium on deep learning challenges, advances and applications. With no hesitation, I recommend it as a “must read” reference for researchers, practitioners, and higher research degrees students who want to experience truly exciting deep dive into a full-fledged deep learning. Two renowned global class experts in the field edit the book, which for me is always the best indicator of the importance and quality of the content. I would like to finish this brief review expanding a bit further on my personal viewpoint regarding the book. For any active researcher like myself, the most important advantage of the book is the fact that it leaves its reader with a heightened ability to think – in different ways – about developing, evaluating, and implementing deep learning-based techniques and technologies in real life environments.
Boron-Doped Diamond/GaN Heterojunction—The Influence of the Low-Temperature Deposition
- Michał Sobaszek
- Marcin Gnyba
- Sławomir Kulesza
- Mirosław Bramowicz
- Tomasz Klimczuk
- Robert Bogdanowicz
2021 Pełny tekst Materials
We report a method of growing a boron-doped diamond film by plasma-assisted chemical vapour deposition utilizing a pre-treatment of GaN substrate to give a high density of nucleation. CVD diamond was deposited on GaN substrate grown epitaxially via the molecular-beam epitaxy process. To obtain a continuous diamond film with the presence of well-developed grains, the GaN substrates are exposed to hydrogen plasma prior to deposition. The diamond/GaN heterojunction was deposited in methane ratio, chamber pressure, temperature, and microwave power at 1%, 50 Torr, 500 C, and 1100 W, respectively. Two samples with different doping were prepared 2000 ppm and 7000 [B/C] in the gas phase. SEM and AFM analyses revealed the presence of well-developed grains with an average size of 100 nm. The epitaxial GaN substrate-induced preferential formation of (111)-facetted diamond was revealed by AFM and XRD. After the deposition process, the signal of the GaN substrate is still visible in Raman spectroscopy (showing three main GaN bands located at 565, 640 and 735 cm1) as well as in typical XRD patterns. Analysis of the current–voltage characteristics as a function of temperature yielded activation energy equal to 93.8 meV.
Borrelia burgdorferi BmpA-BBK32 and BmpA-BBA64: New Recombinant Chimeric Proteins with Potential Diagnostic Value
- Weronika Grąźlewska
- Bartłomiej Ferra
- Lucyna Holec-Gąsior
2021 Pełny tekst Pathogens
Currently, the diagnosis of Lyme disease is based mostly on two-tiered serologic testing. In the new generation of immunoenzymatic assays, antigens comprise whole-cell lysates of members of the Borrelia burgdorferi sensu lato (s.l.) species complex, with the addition of selected recombinant proteins. Due to the high diversity of members of the B. burgdorferi s.l. genospecies and the low degree of conservation among the amino acid sequences of their proteins, serodiagnostic methods currently in use are not sufficient for the correct diagnosis of borreliosis. Two divalent chimeric proteins (BmpA-BBK32 and BmpA-BBA64) were expressed in Escherichia coli. Following purification by one-step metal-affinity chromatography, preparations were obtained containing milligram levels of chimeric protein exhibiting electrophoretic purity in excess of 98%. Reactivity of the new chimeric proteins with specific human IgG antibodies was preliminarily determined by Western blot. For this purpose, 20 negative sera and 20 positive sera was used. The new chimeric proteins were highly reactive with IgG antibodies contained in the serum of patients suffering from borreliosis. Moreover, no immunoreactivity of chimeric proteins was observed with antibodies in the sera of healthy people. These promising results suggest that new chimeric proteins have the potential to discriminate between positive and negative sera.
Bortezomib induces methylation changes in neuroblastoma cells that appear to play a significant role in resistance development to this compound
- Karolina Łuczkowska
- Katarzyna Ewa Sokołowska
- Olga Taryma-Leśniak
- Krzysztof Pastuszak
- Anna Supernat
- Jonas Bybjerg-Grauholm
- Lise Lotte Hansen
- Edyta Paczkowska
- Tomasz K. Wojdacz
- Bogusław Machaliński
2021 Pełny tekst Scientific Reports
The anticancer activity of bortezomib (BTZ) has been increasingly studied in a number of indications and promising results for the use of this treatment have been shown in neuroblastoma. As BTZ treatment is usually administered in cycles, the development of resistance and side effects in patients undergoing therapy with BTZ remains a major challenge for the clinical usage of this compound. Common resistance development also means that certain cells are able to survive BTZ treatment and bypass molecular mechanisms that render BTZ anticancer activity. We studied the methylome of neuroblastoma cells that survived BTZ treatment. Our results indicate that BTZ induces pronounced genome wide methylation changes in cells which recovered from the treatment. Functional analyses of identified methylation changes demonstrated they were involved in key cancer pathology pathways. These changes may allow the cells to bypass the primary anticancer activity of BTZ and develop a treatment resistant and proliferative phenotype. To study whether cells surviving BTZ treatment acquire a proliferative phenotype, we repeatedly treated cells which recovered from the first round of BTZ treatment. The repetitive treatment led to induction of the extraordinary proliferative potential of the cells, that increased with subsequent treatments. As we did not observe similar effects in cells that survived treatment with lenalidomide, and non‑treated cells cultured under the same experimental conditions, this phenomenon seems to be BTZ specific. Overall, our results indicate that methylation changes may play major role in the development of BTZ resistance.
Bounds on isolated scattering number
- Marcin Jurkiewicz
2021
The isolated scattering number is a parameter that measures the vulnerability of networks. This measure is bounded by formulas de- pending on the independence number. We present new bounds on the isolated scattering number that can be calculated in polynomial time.
Bounds on isolated scattering number
- Marcin Jurkiewicz
2021 ANZIAM JOURNAL
The isolated scattering number is a parameter that measures the vulnerability of networks. This measure is bounded by formulas de- pending on the independence number. We present new bounds on the isolated scattering number that can be calculated in polynomial time.
Brief Literature Review and Classification System of Reliability Methods for Evaluating the Stability of Earth Slopes
- Jarosław Przewłócki
2021 Pełny tekst Sustainability
The issue of slope stability is one of the most important and yet most difficult geotechnical problems. Assessing slope stability is particularly difficult because of the many uncertainties involved in the process. To take these uncertainties into account, probabilistic methods are used, and the reliability approach is adopted. There are many methods for reliability assessment of earth slope stability. However, there is no system that would organize all of these methods in an unambiguous way. In fact, these methods can be classified in different ways: by assignment to a deterministic classification of methods, by description of uncertainties of soil parameters, by level of reliability according to the theory of reliability, etc. The huge number of articles summarizing the research in this field, but in various “disordered” directions, certainly do not facilitate the understanding or ultimately the practical application of the reliability approach by the engineer. The paper proposes a universal classification system of reliability methods for evaluating the stability of earth slopes. This proposal is preceded by a brief literature review of both historical background and contemporary research on reliability analysis of earth slope stability.
Budowanie strategii edukacyjnej uczelni z uwzględnieniem wykorzystania e-technologii – wnioski z analizy doświadczeń uczelni technicznej
- Anita Dąbrowicz-Tlałka
- Magdalena Musielak
2021 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Artykuł zawiera wnioski z podsumowania działań koncepcyjnych i organizacyjnych jakie zostały przeprowadzone w toku rozbudowy uczelnianej platformy edukacyjnej i jej integracji z systemami uczelni. Autorki podjęły starania, aby na podstawie analizowanego przypadku uczelni technicznej, przedstawić rekomendacje związane z tworzeniem edukacyjnej strategii uczelni w zakresie zdalnej edukacji. W artykule przedstawiono dane z ankiet oraz dane dotyczące systemów edukacyjnych Politechniki Gdańskiej, które uzyskano w okresie zawieszenia kształcenia na uczelniach.
Burnout Investigation of Small Diameter Tubes Immersed in Nanofluids
- Janusz Cieśliński
- Katarzyna Ronewicz
2021 Pełny tekst ENERGIES
This paper deals with research into pool boiling critical heat flux (CHF) of water–Al2O3, water–TiO2 and water–Cu nanofluids on horizontal stainless steel tubes. The experiments were conducted under atmospheric pressure. Nanoparticles were tested at concentrations of 0.001%, 0.01%, 0.1% and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. Although dispersants were not used to stabilize the suspension, the solutions tested showed satisfactory stability. Experimental measurements were performed with stainless steel tubes of three outside diameters: 1.6, 3 and 5 mm. Enhancement of CHF was observed to be independent of the concentration and material of the nanoparticles and tube diameter, with simultaneous heat transfer degradation. Built up during the boiling process, nanolayers improve substantially the heating surface wettability. A correlation is suggested for the CHF prediction during pool boiling of nanofluids.
Business continuity management framework for Industry 4.0 companies regarding dependability and security of the ICT and ICS/SCADA system
- Kazimierz Kosmowski
2021 Pełny tekst
This chapter addresses a business continuity management (BCM) framework for the Industry 4.0 companies including the organizational and technical solutions, regarding the dependability and security of the information and telecommunication technology (ICT), and the industrial control system (ICS) / supervisory control and data acquisition (SCADA) system. These technologies and systems play nowadays important roles in modern advanced manufacturing systems and process plants due to their openness to external systems and networks using various communication channels. It gives on the one hand, some advantages in effective realization of technological and business processes, logistics and distribution of goods, but, on the other hand, makes the company assets and resources potentially vulnerable to some threats with relevant risks. The chapter outlines some ideas related to designing a business continuity management system (BCMS) based on defined processes and procedures. Such system includes planning of changes in organization / industrial company, nonconformity issues, and planning corrective actions. In a final part of this chapter the leadership importance, and staff awareness and responsibility are emphasized to create a robust and healthy corporate culture based on accepted values, properly spread among the employees. It is beneficial for shaping good organizational culture, and then safety and security culture. The BCM approach outlined in this chapter distinguishes both preventive and recovery activities regarding suggestions in selected international standards and domain publications.
Buzz-based honeybee colony fingerprint
- Tymoteusz Cejrowski
- Julian Szymański
2021 Pełny tekst COMPUTERS AND ELECTRONICS IN AGRICULTURE
Non-intrusive remote monitoring has its applications in a variety of areas. For industrial surveillance case, devices are capable of detecting anomalies that may threaten machine operation. Similarly, agricultural monitoring devices are used to supervise livestock or provide higher yields. Modern IoT devices are often coupled with Machine Learning models, which provide valuable insights into device operation. However, the data preparation step for ML models has to be addressed differently for industrial and agriculture cases. Animals are characterized by their circadian rhythms and seasonal dependence, which can bias the accuracy of classifiers. In the presented work, a Design-of-Experiment (DoA) approach for extracting valuable bee colony audio data is described. With the presented methods, it is possible to precisely define the most distinctive bee hours where unique colony sounds are emitted. The first step of the data filtering process is based on identifying the ambient temperatures that are conducive to its operation. The second step provides the unique hours specification based on the hives’ characteristics comparison where dissimilar time periods are being marked. For this comparison, the most noticeable difference between the colonies is calculated with MSE integral and thus the trend’s joint component is removed. A new concept of a bees’ fingerprint was introduced for the identification of the particular bee colony.
Bypass kolejowy dla wiaduktu łukowego i kratownicowego w ciągu modernizowanej linii kolejowej E59 na odcinku Wronki – Dobiegniew
- Agnieszka Makowska
- Cezary Najda
- Anna Banaś
2021 Mosty
W artykule przedstawiono realizacje bypassu kolejowego, zlokalizowanego nieopodal miejscowości Krzyż Wielkopolski w ciągu linii kolejowej E59 na skrzyżowaniu z linią kolejową 203. Wariantowa analiza kilku zaproponowanych rozwiązań wykazała, ze wykonstruowanie bypassu na czas prowadzenia prac modernizacyjnych pozwoli na utrzymanie ciągłości ruchu kolejowego, nie stworzy nadmiernych problemów podróżnym, a jednocześnie pozwoli na obniżenie kosztów inwestycji w stosunku do wdrożenia komunikacji zastępczej.
By-Products from Food Industry as a Promising Alternative for the Conventional Fillers for Wood–Polymer Composites
- Aleksander Hejna
- Jerzy Korol
- Paulina Kosmela
- Anton Kuzmin
- Adam Piasecki
- Arkadiusz Kulawik
- Błażej Chmielnicki
2021 Pełny tekst Polymers
The present paper describes the application of two types of food-industry by-products, brewers’ spent grain (BSG), and coffee silverskin (ŁK) as promising alternatives for the conventional beech wood flour (WF) for wood–polymer composites. The main goal was to investigate the impact of partial and complete WF substitution by BSG and ŁK on the processing, structure, physicochemical, mechanical, and thermal properties of resulting composites. Such modifications enabled significant enhancement of the melt flowability, which could noticeably increase the processing throughput. Replacement of WF with BSG and ŁK improved the ductility of composites, which affected their strength however. Such an effect was attributed to the differences in chemical composition of fillers, particularly the presence of proteins and lipids, which acted as plasticizers. Composites containing food-industry by-products were also characterized by the lower thermal stability compared to conventional WF. Nevertheless, the onset of decomposition exceeding 215 ◦C guarantees a safe processing window for polyethylene-based materials.
Cable-stayed bridges. Basic static schemes
- Krzysztof Żółtowski
2021 Pełny tekst Archives of Civil Engineering
The paper presents an overview of shaping of cable-stayed bridges. Historical background, basic static sketches and overview of selected bridges are included. Selected natural solutions and interesting unrealized projects were presented. Basic ideas and most important principals are discussed. The examples and sketches were given an author's comment. Static diagrams of two pylon structures with three variants of the arrangement of cables are presented. The details important for the structure were discussed and the consequences of choosing the variant were indicated. Mono-pylon structures in asymmetric and symmetrical arrangements are shown. the solutions are discussed and the details important for the structure are indicated. An overview of multi-pylon structures is also presented, paying attention to important details. All the discussed static diagrams were enriched with realized examples. The advantages and disadvantages of individual structural solutions are presented. The main ideas allowing to achieve the goal in the implementation of non-standard suspended structures were also indicated.
Calibration-Free Single-Anchor Indoor Localization Using an ESPAR Antenna
- Mateusz Groth
- Krzysztof Nyka
- Łukasz Kulas
2021 Pełny tekst SENSORS
In this paper, we present a novel, low-cost approach to indoor localization that is capable of performing localization processes in real indoor environments and does not require calibration or recalibration procedures. To this end, we propose a single-anchor architecture and design based on an electronically steerable parasitic array radiator (ESPAR) antenna and Nordic Semiconductor nRF52840 utilizing Bluetooth Low Energy (BLE) protocol. The proposed algorithm relies on received signal strength (RSS) values measured by the receiver equipped with the ESPAR antenna for every considered antenna radiation pattern. The calibration-free concept is achieved by using inexpensive BLE nodes installed in known positions on the walls of the test room and acting as reference nodes for the positioning algorithm. Measurements performed in the indoor environment show that the proposed approach can successfully provide positioning results better than those previously reported for single-anchor ESPAR antenna localization systems employing the classical fingerprinting method and relying on time-consuming calibration procedures.