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Repozytorium publikacji
Politechniki Gdańskiej

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  • Miniaturization of ESPAR Antenna Using Low-Cost 3D Printing Process
    • Mateusz Czeleń
    • Mateusz Rzymowski
    • Krzysztof Nyka
    • Łukasz Kulas
    2020 Pełny tekst

    In this paper, the miniaturized electronically steerable parasitic array radiator (ESPAR) antenna is presented. The size reduction was obtained by embedding its active and passive elements in polylactic acid (PLA) plastic material commonly used in low-cost 3D printing. The influence of 3D printing process imperfections on the ESPAR antenna design is investigated and a simple yet effective method to compensate them has been proposed. An antenna prototype was fabricated and measured, which showed that the experimental and simulated results are in good agreement. Realized antenna is characterized by 5.6 dBi peak gain and reflection coefficient of -17.6 dB. Base radius reduction of 23% and occupied area reduction of 40% were achieved.

  • Minimalizacja błędu estymaty położenia obiektu przez redukcję błędów radiowych pomiarów odległości
    • Olga Błaszkiewicz
    • Krzysztof Cwalina
    • Alicja Olejniczak
    • Piotr Rajchowski
    • Jarosław Sadowski
    2020 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    Utrzymująca się popularność modułu radiowego DWM1000 firmy DecaWave do zastosowań lokalizacyjnych przyczyniła się do przeprowadzenia analizy wpływu błędów radiowych pomiarów odległości na dokładność estymaty położenia lokalizowanego obiektu. W badaniach skupiono się na analizie błędów radiowych pomiarów odległości dla węzłów oddalonych od siebie w zakresie od kilkudziesięciu centymetrów do dziesięciu metrów. Ze względu na błąd rzędu dziesiątek centymetrów dla bliskich odległości pomiędzy węzłami, tj. 0,5 m – 4 m, zaproponowano nieliniowy model korekty błędów zależny wyłącznie od wartości radiowych pomiarów odległości i porównano go z modelem korekty zaproponowanym przez firmę DecaWave. Model korekty opracowano na podstawie pomiarów przeprowadzonych w środowisku wewnątrzbudynkowym.

  • Minimising the Churn Out of the Service by Using a Fairness Mechanism
    • Izabela Mazur
    • Jacek Rak
    • Krzysztof Nowicki
    2020

    The paper proposes an algorithm of bandwidth distribution, ensuring fairness to end-users in computer networks. The proposed algorithm divides users into satisfied and unsatisfied users. It provides fairness in terms of quality of experience (QoE) for satisfied users and quality of service (QoS) for unsatisfied users. In this paper, we present detailed comparisons relevant to service providers to show the advantages of the proposed algorithm over the popular max-min algorithm. Our algorithm is designed to provide service providers with a mechanism to minimize the number of end-user terminations of service, which is one of the most desired factors for service providers.

  • Minute and diverse in fossil sticky stuff: Tanytarsini (Diptera: Chironomidae) from early Eocene Indian Cambay amber
    • Marta Zakrzewska
    • Hukam Singh
    • Ewa Wagner-Wysiecka
    • Wojciech Giłka
    2020 Pełny tekst ZOOLOGICAL JOURNAL OF THE LINNEAN SOCIETY

    We here present a pioneering systematic review of fossil dipterans of the tribe Tanytarsini (family Chironomidae) discovered in Indian amber from Cambay. The specimens examined belong to five species: Gujaratomyia miripes, Stempellina stebneri sp. nov., Stempellinella pollex sp. nov., Tanytarsus forfex sp. nov. and Tanytarsus ramus sp. nov., which are described. All species belong to the oldest known Tanytarsini and come from the Cambay shale formation in Tadkeshwar, dated to the early Eocene (~54 Mya). Displaying unusual characters/structures of diagnostic and phylogenetic importance, the specimens studied are discussed against the background of the evolution and systematics of the oldest fossil (Eocene) and extant representatives in the tribe. An updated checklist and key to the identification of genera and species of Tanytarsini from Eocene amber is also provided. The spectral characteristics and physical properties of Cambay amber are similar to those of glessite resins, which are discussed in detail in order to substantiate the identity of the amber and the origin of the inclusions studied.

  • Mitigation of Fake Data Content Poisoning Attacks in NDN via Blockchain
    • Stanisław Barański
    • Jerzy Konorski
    2020

    Abstract—Information-centric networks struggle with content poisoning attacks (CPAs), especially their stronger form called Fake Data CPA, in which an intruder publisher uploads content signed with stolen credentials. Following an existing graphinfection based approach leveraging the constrained time when stolen credentials are useful, we design a blockchain-based mitigation scheme for Named Data Networking architectures. We postulate Proof-of-Time verification to distinguish between intruder and legitimate publishers, and argue that blockchain solutions can implement it natively. The proposed scheme, using the Federated Byzantine Agreement protocol, is described in detail and found to be a valuable alternative to the graph infection approach, superior with respect to outcome determinism, resiliency, and fault tolerance.

  • Mitigation of the Flow Maldistribution in Minichannel and Minigap Heat Exchangers by Introducing Threshold in the Manifolds
    • Paweł Dąbrowski
    2020 Pełny tekst Journal of Applied Fluid Mechanics

    In the present paper, a detailed numerical investigation has been carried out to analyze the flow maldistribution in 50 parallel rectangular cross-section (1 mm depth and 1 mm width) minichannels and minigap section (1 mm depth and 99 mm width) with rectangular/trapezoidal manifolds in Z-type flow configuration. The author carried out numerical investigation with various mass flowrates, namely 0.05 kg/s, 0.1 kg/s and 0.2 kg/s which results in Reynolds number of 1532, 3064, 6128 respectively. A novel approach for the mitigation of non-uniform flow has been proposed introducing threshold at the entrance of the minigeometry section. The conventional case without threshold (as reference) and 1 mm, 3 mm and 7 mm threshold were introduced. The threshold has been employed by making a manifolds’ depth bigger than section’s depth. The maldistribution coefficient can be reduced twice in minigap section or three times in the minichannel section already with the 1 mm threshold as compared to the arrangement without threshold. It is found that rectangular manifold gives lower maldistribution coefficient than trapezoidal manifold which corresponds with actual state of the art. The distribution is more uniform in minichannel section than in minigap section for the same inlet parameters. To obtain uniform distribution of fluid flow should be stabilized already at the inlet manifold, at the entrance to the minichannel or minigap section. That was done by introducing the threshold in the manifolds, which is novelty of this study.

  • MnxCo3-xO4 spinel oxides as efficient oxygen evolution reaction catalysts in alkaline media
    • Krystian Lankauf
    • Karolina Cysewska
    • Jakub Karczewski
    • Aleksandra Mielewczyk-Gryń
    • Karolina Górnicka
    • Grzegorz Cempura
    • Ming Chen
    • Piotr Jasiński
    • Sebastian Molin
    2020 Pełny tekst INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    The design of efficient electrocatalysts for oxygen evolution reaction (OER) is an essential task in developing sustainable water splitting technology for the production of hydrogen. In this work, manganese cobalt spinel oxides with a general formula of MnxCo3-xO4 (x=0, 0.5, 1, 1.5, 2) were synthesised via a soft chemistry method. Non-equilibrium mixed powder compositions were produced, resulting in high electrocatalytic activity. The oxygen evolution reaction was evaluated in an alkaline medium (1 M KOH). It was shown that the addition of Mn (up to x ≤ 1) to the cubic Co3O4 phase results in an increase of the electrocatalytic performance. The lowest overpotential was obtained for the composition designated as MnCo2O4, which exhibited a dual-phase structure (~30% Co3O4 + 70% Mn1.4Co1.6O4): the benchmark current density of 10 mA cm-2 was achieved at the relatively low overpotential of 327 mV. The corresponding Tafel slope was determined to be ~79 mV dec-1. Stabilities of the electrodes were tested for 25 hours, showing degradation of the MnCo2O4 powder, but no degradation, or even a slight activation for other spinels.

  • Mobile chromatographs and spectrometers for the analysis of chemical warfare agents
    • Waldemar Wardencki
    • Zygfryd Witkiewicz
    • Sławomir Neffe
    2020 Pełny tekst

    This article describes the technological state of readiness regarding mobile chromatographs and spectrometers and their appiicability for the analysis of chemical warfare agents (CWAs), degradation products, simulants, and precursors.

  • Mobile Cloud computing architecture for massively parallelizablegeometric computation
    • Víctor Sánchez Ribes
    • Higinio Mora-Mora
    • Andrzej Sobecki
    • Francisco José Mora Gimeno
    2020 Pełny tekst COMPUTERS IN INDUSTRY

    Cloud Computing is one of the most disruptive technologies of this century. This technology has been widely adopted in many areas of the society. In the field of manufacturing industry, it can be used to provide advantages in the execution of the complex geometric computation algorithms involved on CAD/CAM processes. The idea proposed in this research consists in outsourcing part of the load to be com- puted in the client machines to the cloud through the Mobile Cloud Computing paradigm. This practice gives substantial benefits to both the clients and the software-provider in terms of costs, flexibility, ubiq- uity and performance. In this document, an outsourcing architecture is proposed based on this paradigm. Extensive experiments have been done using highly parallelizable computational geometry operations to show the strengths and weaknesses of the proposal in combination of specialized computing plat- forms in the cloud. The results suggest that there are some issues that affect the overall performance and the stability of the QoS: the network communication delay, and the number of simultaneous clients and multiple requests. Some solutions have been proposed to face these challenges.

  • Mobile Security: Threats and Best Practices
    • Paweł Weichbroth
    • Łukasz Łysik
    2020 Pełny tekst Mobile Information Systems

    Communicating mobile security threats and best practices has become a central objective due to the ongoing discovery of new vulnerabilities of mobile devices. To cope with this overarching issue, the goal of this paper is to identify and analyze existing threats and best practices in the domain of mobile security. To this extent, we conducted a literature review based on a set of keywords. The obtained results concern recognizable threats and established best practices in the domain of mobile security. Afterwards, this outcome was put forward for consideration by mobile application users (n = 167) via a survey instrument. To this end, the results show high awareness of the threats and their countermeasures in the domain of mobile applications. While recognizing the risks associated with physical and social factors, the majority of respondents declared the use of built-in methods to mitigate the negative impact of malicious software and social-engineering scams. The study results contribute to the theory on mobile security through the identification and exploration of a variety of issues, regarding both threats and best practices. Besides this, this bulk of up-to-date knowledge has practical value which reflects in its applicability at both the individual and enterprise level. Moreover, at this point, we argue that understanding the factors affecting users’ intentions and motivations to accept and use particular technologies is crucial to leverage the security of mobile applications. Therefore, future work will cover identifying and modeling users’ perceptions of the security and usability of mobile applications.

  • Model funkcjonalny wpływu czynników na jakość produktu w branży piekarniczej
    • Radosław Drozd
    2020 Aparatura Badawcza i Dydaktyczna

    W artykule zostały przedstawione czynniki, które mają wpływ na jakość produktu w branży piekarniczej. Tym produktem jest pieczywo, a w szczególności chleb, który stanowi od 80% do 90% jego ogólnej produkcji. Autor wyodrębnił czynniki wpływające na jakość produktu i usystematyzował je, a następnie opisał. Podzielone one zostały na 3 grupy funkcjonujące w procesie produkcyjnym, a następnie na podgrupy. Podstawowe grupy czynników, które mają wpływ na jakość produktu to: czynniki surowcowe, czynniki technologiczne i czynniki organizacyjno-techniczne. Podsumowaniem całości opracowania jest opisowy model funkcjonalny wpływu czynników na jakość produktu w branży piekarniczej.

  • Model of aeration system at biological wastewater treatment plant for control design purposes
    • Robert Piotrowski
    • Tomasz Ujazdowski
    2020 Pełny tekst

    The wastewater treatment plant (WWTP) is a dynamic, very complex system, in which the most important control parameter is the dissolved oxygen (DO) con-centration. The air is supplied to biological WWTP by the aeration system. Aera-tion is an important and expensive activity in WWTP. The aeration of sewage ful-fils a twofold role. Firstly, oxygen is provided as the main component for biolog-ical processes. Secondly, it supports mixing the sludge with the delivered sew-age, which helps to treat the sewage. The paper proposes a model of the aeration system for biological WWTP located in Northeast Poland. This aeration system consists of the blowers, the main collector pipeline, three lines of the aeration with different diameters and lengths and diffusers. This system is a nonlinear dy-namic system with faster dynamics compared to the internal dynamics of the DO at the biological WWTP. Control of the aeration system is also difficult in terms of control of the DO. A practical approach to model identification and validation is proposed. Simulation tests for aeration system at Matowskie Pastwiska WWTP are presented.

  • Model of Nutrient and Pesticide Outflow with Surface Water to Puck Bay (Southern Baltic Sea)
    • Dominika Kalinowska
    • Paweł Wielgat
    • Tomasz Kolerski
    • Piotr Zima
    2020 Pełny tekst Water

    Coastal basins are particularly exposed to the adverse impact of anthropogenic stress. In many places, despite only the seasonal increase in the number of residents, progressive urbanization and associated changes in the catchment characteristics are noticeable. Puck Bay is part of the Gulf of Gdansk and belongs to the Baltic Sea. Although the area of Puck Bay is covered by the Natura 2000 Network, this has not saved it from eutrophication problems. As part of the work on a complex coastal basin analysis (WaterPUCK project), the Soil and Water Assessment Tool (SWAT) model was used to determine the agricultural impact on water quality in rivers with a flow into Puck Bay: Reda, Gizdepka, Płutnica, and Bł ˛adzikowski Stream. The results include the loads of nutrients and pesticides that flow out from the agricultural areas of Puck community into Puck Bay. In this article, special attention has been paid to the impact of precipitation on the quality of water at the outflow of rivers into the Bay of Puck, because it is a decisive element in the amount of nutrients leached along with surface runoff to watercourses and then into the Gulf. The distribution of precipitation thus affects the amount of nutrients absorbed by plants. Modeling the effects of agricultural practices, taking into account long-term meteorological forecasts, is helpful in attempts to reduce the amount of pollutants entering the Baltic Sea.

  • Model systemu zarządzania usługami według metodologii design-thinking
    • Malwina Studzińska
    2020 Pełny tekst

    W literaturze przedmiotu brakuje jednoznacznych wskazań odnośnie decyzji o wyborze najbardziej odpowiedniego modelu projektowania usług, szczególnie w kontekście różnych uwarunkowań dla poszczególnych sektorów rynku. Opracowany algorytm umożliwia samodzielne rozwiązanie problemu doboru modelu wewnątrz organizacji, bez konieczności zatrudniania zewnętrznego specjalisty. Algorytm skierowany jest do organizacji w fazie przygotowawczej do projektowania usługi design-thinking. Realizacja zaproponowanych w ramach niego instrukcji zgodnie z określonymi parametrami, zakończy się skierowaniem do najbardziej optymalnego spośród licznych dostępnych modeli, który pozwoli uzyskać usługę uwzględniającą indywidualne uwarunkowania organizacji. Kolejne kroki algorytmu polegają na rozwiązywaniu powstałych sytuacji decyzyjnych, m.in. w zakresie wskazania i hierarchizacji determinant jakości uwzględniających specyfikę sektora danej firmy czy wyboru globalnego celu określającego oczekiwaną usługę. Synteza dużej ilości danych posiadanych przez organizacje w narzędzie o charakterze decyzyjnym była możliwa dzięki zastosowaniu procedury analizy systemowej. Logika rozmyta została wybrana jako podejście metodyczne do analizy porównawczej próby bardzo podobnych do siebie modeli design-thinking. Zastosowanie algorytmu generuje liczne korzyści ekonomiczne, w tym efektywne wykorzystanie zasobów ludzkich firmy.

  • Model zaangażowania w relacji usługodawca-klient
    • Sławomir Ostrowski
    2020

    W niniejszej monografii przedstawiono rozwiązania pozwalające lepiej zrozumieć złożoność relacji występujących pomiędzy usługodawcami a klientami oraz metody, które pozwalają tę wiedzę wykorzystać w doskonaleniu procesów organizacji usługowych. Monografia podejmuje problem kształtowania zaangażowania na styku usługodawca–klient jako wstępnego i koniecznego warunku rozwijania relacji w usługach. Opierając się na klasycznej drabinie lojalności klienta, autor opracował pięciowarstwowy model rozwoju wzajemnego zaangażowania usługodawca–klient oraz poddał ten model badaniom, wykorzystując dane pozyskane ze studiów przypadków. Zaproponowany model zaangażowania autor opisuje w monografii łącznie z mechanizmem kształtowania wzajemnego zaangażowania w relacji usługodawca–klient, który wpływa na możliwość budowy i rozwijania wzajemnych relacji, opartych na wymianie pomiędzy usługodawcą a klientem różnorodnych zapytań, zachęt, komunikatów i wiadomości. Model zawiera 93 czynniki składowe, które wpływają na kształtowanie zaangażowania usługodawca–klient. Model stanowi praktyczne narzędzie badawcze i diagnostyczne, które umożliwia ocenę poziomu zaangażowania po stronie klienta i po stronie usługodawcy oraz analizę czynników składowych zaangażowania, zwłaszcza powiązanych z zaobserwowanymi przeszkodami w procesie komunikacji realizowanym z wykorzystaniem technologii interaktywnych. W monografii zaprezentowano również, w jaki sposób model wizualizuje wyniki analiz w formie raportów diagnostycznych, które pozwalają diagnozować przeszkody w rozwoju zaangażowania i relacji usługodawca–klient.Praktyczne wykorzystanie modelu umożliwia menedżerom wyższego szczebla, kierownikom projektu, specjalistom w projektowaniu oraz udoskonalaniu usług: - ocenę i analizę czynników składowych zaangażowania; - wizualizację wyników analizy w formie raportów diagnostycznych; - podejmowanie działań niezbędnych do usunięcia przeszkód we wskazanych obszarach/czynnikach i podniesienia zaangażowania na wyższy poziom w celu wzmocnienia mechanizmu rozwoju relacji usługodawca–klient. Model zaangażowania w praktycznym zastosowaniu może być pomocnym narzędziem wypełniającym lukę aplikacyjną w zakresie diagnozowania barier w rozwoju zaangażowania i relacji usługodawca–klient, szczególnie w sytuacjach, gdy usługodawca jest zainteresowany pozyskaniem zaangażowania klientów do współudziału w doskonaleniu usług, realizowanym zgodnie z podejściem współprojektowania w ramach modelu otwartych innowacji.

  • Modele ruchu w nowoczesnym zarządzaniu transportem drogowym
    • Jacek Oskarbski
    2020 Pełny tekst Transport Miejski i Regionalny

    Wdrożenie i rozwijanie wielopoziomowego modelu podróży i sieci transportowej (MST), w ramach Systemu Planowania Ruchu (SPR), usprawniającego zarządzanie transportem w systemach transportowych z wykorzystaniem usług oferowanych przez Inteligentne Systemy Transportu, może stanowić wsparcie naukowe dla krajowych, regionalnych lub lokalnych administracyjnych jednostek planistycznych i operacyjnych w usprawnieniu systemowego zarządzania ruchem drogowym, w działaniach zmierzających do poprawy poziomu sprawności i bezpieczeństwa w transporcie. W artykule przedstawiono koncepcję, realizację oraz przykłady zastosowań SPR wraz z MST jako kluczowych elementów systemów zarządzania transportem. Zostały one wdrożone w wyniku badań naukowych nad integracją modeli podróży, ruchu i sieci transportowej w ramach realizacji Zintegrowanego Systemu Zarządzania Ruchem TRISTAR w Trójmieście oraz projektów badawczych CIVITAS DYN@MO „DYNamic citizens @ctive for sustainable Mobility”, FLOW „Furthering Less Congestion by Creating Opportunities For More Walking and Cycling” i RID-4D „Wpływ stosowania usług Inteligentnych Systemów Transportowych na poziom bezpieczeństwa ruchu drogowego”.

  • Modele rurociągowych procesów przepływowych
    • Zdzisław Kowalczuk
    • Marek Tatara
    2020

    W rozdziale analizowane jest zagadnienie modelowania oraz parametryzacji procesu przepływu w rurociągach przemysłowych. W pierwszej kolejności przedstawia się bazowy model dyskretny, do którego odnoszone są pozostałe syntezowane rozwiązania. Następnie proponuje się metodę aproksymacji diagonalnej (AMDA), w której stosuje się przybliżenia trójdiagonalnych podmacierzy macierzy rekombinacji za pomocą ich diagonalnych odpowiedników -- co pozwala na zdeterminowanie jawnej formuły na odwrotność tej macierzy. Kolejną propozycję stanowi model Thomasa (ATM), w której dokonuje się przeformułowania modelu bazowego do postaci, względem której można zastosować algorytm Thomasa oraz osiągnąć złożoność obliczeniową O(N). Czwartą propozycję stanowi analityczny model AMSS charakteryzujący stan ustalony (po zaniku procesów przejściowych). W dalszej części opisuje się taki sposób parametryzacji modeli dyskretnych w czasie i przestrzeni, który zapewnia maksymalny zapas stabilności numerycznej syntezowanego modelu, co zweryfikowano symulacyjnie. Na koniec porównano opracowane modele biorąc pod uwagę ich dokładność i czas obliczeń względem wzorcowego modelu bazowego.

  • Modeling of a Quasi-Resonant DC Link Inverter Dedicated to Common-Mode Voltage and Ground Current Reduction
    • Marek Turzyński
    • Michal Frivaldsky
    2020 Pełny tekst ENERGIES

    In this paper, the modeling methodology of the AC drive system with a Parallel Quasi-Resonant DC Link Inverter (PQRDCLI) is described. A presented modeling approach is an attractive tool used for the effective evaluation of a common-mode (CM) voltage and grounds current reduction methods. Designed models of inverter, induction machine (IM), and cable are simple, thus the methods for parameter extraction are not complicated. Verification of the proposed modeling approach was realized with the use of the the Synopsys (Mountain View, CA, USA) SABER simulator, while simulation results were experimentally verified. Operation principles of the proposed PQRDCLI converter topology are also described. Based on simulation and experimental results, it was confirmed that the proposed PQRDCLI solution represents required performance within the reduction of common-mode voltage and ground current in electric drives. Moreover, comparisons from a simulation complexity point of view have been performed to the existing methods. The evaluation is being shown at the end of the paper. It is confirmed that the presented method is simple, fast, accurate, and robust as well.

  • Modeling of wood frame structures with different insulation materials under damaging dynamic loading
    • Marcin Szczepański
    • Wojciech Migda
    • Robert Jankowski
    2020 AIP Conference Proceedings

    Wood frame buildings are very popular in regions that are exposed to different dynamic excitations, such as damaging earthquakes. Their seismic resistance is really important in order to prevent structural damages and human losses. This paper presents the results of advanced numerical investigation carried out using the FEM. Based on the models of wall panels, the numerical model of real structure of the wood frame building has been proposed for two cases of thermal insulation (using polyurethane foam and mineral wool). Then, the modal analysis for both models has been conducted so as to compare the frequencies of natural vibrations. Finally, the linear and nonlinear dynamic analyses have been carried out so as to investigate the structural behavior under damaging earthquake excitation. The results of the numerical investigation clearly confirm the beneficial effect of using polyurethane foam as thermal insulation. This can be seen both in the results of modal analysis (higher natural frequencies of building) and seismic analyses, which resulted in a significant reduction in peak values of displacements and accelerations, as compared to the case when mineral wool is applied. Moreover, the results of investigation confirm that the use of the FEM with detailed representation of material and geometric structural properties together with the Newmark algorithm can be considered as the effective approach so as to obtain the accurate response of wood frame building under dynamic loading.

  • Modeling process of planning finished product sales volumes at industrial enterprises in modern economic conditions
    • Kateryna Udachyna
    • Larysa Savchuk
    • Nina Rizun
    2020 Pełny tekst Przedsiębiorstwo we współczesnej gospodarce - teoria i praktyka

    This article presents improving the existing system of planning finished products sales volumes. The influencing factors of the sales volumes in modern economic conditions have been determined: falling world oil prices, the reduction of pipe consumption in the domestic market, the global pandemic. The algorithm of planning finished products sales volumes has been constructed. Calculations based on the Holt forecasting method has been done, which allows to make forecast with trend. Calculations based on real data have been conducted, the model has been adapted to modern pandemic conditions, and impact factors have been identified. The plan of finished products sales volumes with factors of influence has been made. Forecast results obtained have been corrected and presented on periods and on markets. System of planning finished product sales volumes at industrial enterprises in modern economic conditions has been improved.

  • Modeling, simulation, and validation of a TB41 crash test of the H2/W5/B concrete vehicle restraint system
    • Łukasz Pachocki
    • Dawid Bruski
    2020 Pełny tekst Archives of Civil and Mechanical Engineering

    The paper addresses numerical simulations of a concrete vehicle restraint system. The model is described in detail. The advanced material law of the continuous surface cap model was used to analyze the damage locations in concrete barrier segments. The results were validated against the TB41 full-scale crash test. The test was conducted in compliance with European standard EN 1317, and the validation was performed in accordance with the PD CEN/TR 16303 technical report. The force and moment envelopes of the road safety barrier during a vehicle crash are provided. The detailed concrete segment model successfully reproduced the characteristic splitting failure cracks that were found near the connection of the adjacent barrier segments in the actual structure after the full-scale crash test.

  • Modelling of Abdominal Wall Under Uncertainty of Material Properties
    • Katarzyna Szepietowska
    • Izabela Lubowiecka
    • Benoit Magnain
    • Eric Florentin
    2020 Pełny tekst

    The paper concerns abdominal wall modelling. The accurate prediction and simulation of abdominal wall mechanics are important in the context of optimization of ventral hernia repair. The shell Finite Element model is considered, as the one which can be used in patient-specific approach due to relatively easy geometry generation. However, there are uncertainties in this issue, e.g. related to mechanical properties since the properties may vary naturally or as an effect of identification accuracy etc. The aim of the study is to include uncertainties in the modelling and investigate their influence on the model response. The parameters of Gasser-Ogden-Holzapfel hyperelasticmaterialmodel including fibre orientation are treated here as random variables. The uncertainties are propagated with the use of regression based polynomial chaos expansion method. Sobol’ indices are used as the measures of global sensitivity analysis and they provide information about the influence of input uncertainties on the uncertainty of the model output. Uncertainty of parameter affecting stiffness of ground substance (C10) has the highest contribution to the variation of the displacement of chosen point in the center of the abdominal wall.

  • Modelling of dielectric properties of BiNbO4-based microwave ceramics
    • Dionizy Czekaj
    • Agata Lisińska-Czekaj
    • Barbara Garbarz-Glos
    • Wojciech Bąk
    2020 Pełny tekst ARCHIVES OF METALLURGY AND MATERIALS

    In the present paper results of the studies devoted to computer simulations of dielectric response of electroceramics in a frequency domain as well as analysis of the experimental data are given. As an object of investigations BiNbO4-based microwave ceramics was taken. Simulations of the hypothetical impedance response of the ceramic system were performed under assumption of the brick-layer model. A strategy for analysis and modelling of the impedance data for microwave electroceramics was discussed. On the base of the discussed strategy modelling of the dielectric response of BiNbO4 ceramics was performed with the electric equivalent circuit method. The Voigt’s and Maxwell’s circuits were taken as electric models. Parameters of the electric components of the circuits were determined and related to parameters of the ceramic object under study. It was found that fitting quality was good and changed within the range χ2 = 6.78 × 10–4 – 6.77 × 10–5 depending on the model.

  • Modelling of heat and mass transfer through wooden buildings
    • Rachid Méchi
    • Emilia Miszewska
    • Khalifa Slimi
    • Robert Jankowski
    2020 Proceedings of the Institution of Civil Engineers-Engineering and Computational Mechanics

    The aim of this review paper is to examine the most recent available studies dealing with theoretical, numerical and experimental aspects related to modelling of heat and mass transfer through wooden buildings. The main thermophysical, mechanical and hygrometric properties of wood are firstly discussed. Then, the basic governing equations of heat and mass transfer phenomena are presented. A detailed description of the physical problem is also shown. After giving the main results from the comprehensive literature review, the authors propose future possibilities of scientific research studies for a better understanding of the complexity of thermomechanical and optimal designing aspects in wood-based construction.

  • Modelling of heat transfer in supercritical pressure recuperators
    • Dariusz Mikielewicz
    • Jarosław Mikielewicz
    2020 Pełny tekst ENERGY

    In the paper presented is analysis of convective flow heat transfer at supercritical pressure in channels of heat exchanger working in the thermodynamic cycle. The modelling is based on the division of the flow into three regions, namely the heavy fluid, a two phase flow consisting of the heavy and light fluids and finally the light fluid flow. Modelling is concentrated on the region of simultaneous flow of two fluids divided into the zones with the light and heavy fluids. These agents are considered with averaged thermophysical properties in each region. The surface separating the two zones with respective fluids is assumed to feature the pseudocritical temperature. The problem is solved using a previously developed theoretical model based on considerations of energy dissipation in the flow. The fundamental hypothesis in the model is the fact that heat transfer is considered as being dependent on two contributions of energy dissipation, one stemming from the shearing pseudo two-phase flow of the heavy and light fluids, whereas the second contribution comes from the energy dissipation due to exchange of mass between the heavy and light fluids. The results of calculations have been compared with some experimental data from literature showing a good consistency.

  • Modelling study of flow boiling heat transfer of perspective fluids for refrigeration technology
    • Michał Pysz
    • Dariusz Mikielewicz
    2020

    There is a gap of knowledge on flow boiling at high saturation temperatures and higher values of reduced pressure. Thus far, the in-house developed semi-empirical model for flow boiling and flow condensation showed a satisfactory accuracy for calculations for various refrigeration fluids for a wide scope of reduced pressures. This study presents results of calculations of heat transfer coefficient of perspective refrigeration fluids, such as R152a, R32, R245fa, propane and isobutane. Computations were carried out to validate the generalized theoretical in-house model. Study was performed for both conventional and minichannel tubes for a full range of vapour quality. The vast part of the database consists of experiments carried out for low saturation temperature, however in case of R245fa the collected data includes medium and high saturation temperatures. The theoretical results shows a good agreement with experimental data especially for low saturation temperature cases. Most unfavorable outcomes were gained for R245fa. Inconsistency of these results show that more attention should be given to the influence of higher values of reduced pressure on heat transfer predictions.

  • Modelowanie bezpiecznika rozłącznikowego w układach formowania impulsów wielkiej mocy
    • Daniel Kowalak
    • Mikołaj Nowak
    • Mirosław Wołoszyn
    • Kazimierz Jakubiuk
    2020 Pełny tekst Przegląd Elektrotechniczny

    Problem modelowania bezpieczników o dużej dynamice wyłączania prądu jest zagadnieniem szeroko opisywanym w literaturze. Układy takie mogą być wykorzystane w szczególności do formowania impulsów wysokiego napięcia o wartościach rzędu setek kV, charakteryzujących się czasem trwania rzędu ułamka μs. W niniejszej pracy przedstawiono empiryczny model bezpiecznika wielotopikowego, rozszerzony w oparciu o wyniki badań eksperymentalnych.

  • Modelowanie losowych imperfekcji geometrycznych przestrzennych konstrukcji metalowych
    • Jarosław Górski
    • Tomasz Mikulski
    • Magdalena Oziębło
    • Przemysław Sorn
    • Karol Winkelmann
    2020 Inżynieria i Budownictwo

    Imperfekcje geometryczne zbiorników, silosów i powłok siatkowych mogą znaczą-co wpłynąć na ich nośność, a więc powinny być one uwzględniane w obliczeniach komputerowych i w procesie projektowania. Wykazano, że przy podstawowych obcią-żeniach, działających na tego typu konstrukcje, tj. podciśnieniu oraz naporu wiatru i śniegu (w przypadku powłok siatkowych), wykazują wyraźne różnice w porównaniu z analogicznymi wynikami dla tych konstrukcji o idealnej geometrii. Wprowadzenie me-tod probabilistycznych do projektowania oraz szacowanie niezawodności konstrukcji staje się coraz bardziej dostępne i powinno być uwzględniane w projektowaniu.

  • Modelowanie matematyczne transportu lodu w rejonie projektowanego Stopnia Wodnego Siarzewo
    • Tomasz Kolerski
    • Krzystof Wrzosek
    • Przemysław Sobiesak
    • Krzystof Polak
    2020 Gospodarka Wodna

    Przedstawiono wpływ planowanego stopnia Siarzewo na Wiśle na dynamikę lodu w obszarze powyżej i poniżej stopnia. Do tego celu zaimplementowano model matematyczny i przeprowadzono symulacje numeryczne dla różnych scenariuszy. Obliczenia służyły do wyznaczeniu trasy spływu lodu przez zbiornik i poniżej zbiornika oraz sił z jakimi lód będzie oddziaływał na brzegi i dno rzeki oraz projektowane na zbiorniku wyspy. Badaniami objęto odcinek Wisły pomiędzy istniejącym stopniem wodnym Włocławek (km 674,850) a km 715.

  • Models of Brushless Synchronous Generator for Studying Autonomous Electrical Power System
    • Filip Kutt
    2020

    This is a PhD dissertation. The work presented in this monograph was carried out at the Department of Power Electronics and Electrical Machines, Faculty of Electrical and Control Engineering at the Gdansk University of Technology. Developed during the research models of brushless synchronous generator ware verified using FEM based simulations and measurements conducted on the prototype generator. The main focus of the research was toward a brushless synchronous generator in variable frequency modern more electric aircraft power systems. The generator prototype was developed and its performance was analyzed with the focus on the higher rotational velocity of the prototype components and the generated power quality. For this FEM based and circuit models of the generator ware developed and the machine performance was measured and simulated. The proposed circuit model allowed for the inclusion of nonsinusoidal spatial distribution of the magnetic flux along the air gap which in turn allowed for simulation-based power quality analysis.

  • Modernity and postmodernity in architectural education
    • Piotr Czyż
    2020 Pełny tekst World Transactions on Engineering and Technology Education

    The purpose of this article is to present a philosophical education strategy for architecture and interior architecture faculties. The approach is the result of trial and error in lectures and debates with students of philosophical courses in these fields. The presented article is not a result of empirical research, but rather a report on the problems encountered and proposals for their solution. The experience gained from conducting philosophical didactics in architecture faculties allowed the author to note that the main reason for the low interest in philosophical problems is the distance between classically understood philosophy or the history of philosophy and professional issues. Bridging that gap can result in increasing the graduates’ ability to solve problems and strengthen their social competencies.

  • Modernized cathodic protection system for legs of the production rig – Evaluation during ten years of service
    • Krzysztof Żakowski
    • Piotr Igliński
    • Juliusz Orlikowski
    • Kazimierz Darowicki
    • Kinga Domańska
    2020 Pełny tekst OCEAN ENGINEERING

    The modernization of cathodic protection system of the Baltic Beta platform legs is described. It was that the sacrificial anodes cone-shaped groups were to be placed on the seabed at a depth of 80 m. The measurements results of cathodic protection effectiveness during its ten-years operation are presented. The effectiveness was assessed based on the potential value along the entire length of the legs from the sea surface to the seabed. The gained experience indicates that use of sacrificial anode systems mounted on the seabed can be an effective form of cathodic protection of offshore platforms legs. It is basically the only means of anticorrosion protection in case of a platform not able to leave its location for renovation works in a shipyard.

  • Modification of Ground Tire Rubber—Promising Approach for Development of Green Composites
    • Łukasz Zedler
    • Marta Przybysz-Romatowska
    • Józef Haponiuk
    • Shifeng Wang
    • Krzysztof Formela
    2020 Pełny tekst Journal of Composites Science

    Ground tire rubber (GTR) was mechano-chemically modified using a road bitumen 100/150 and two types of organic peroxides: di-(2-tert-butyl-peroxyisopropyl)-benzene (BIB) and dicumyl peroxide (DCP). The impact of used additives on reactive sintering efficiency and physico-mechanical properties of modified GTR was investigated using oscillating disc rheometer measurements, followed by tensile tests and swelling behavior studies. It was found that the application of bitumen and both used peroxides (DCP/BIB) improves processing and reactive sintering efficiency better than untreated GTR. However, the results indicate that BIB is more prone to blooming on the surface of modified GTR, thus limiting (especially at higher content) its application as a modifier and promotor of GTR reactive sintering.

  • Modifications at the C(5) position of pyrimidine nucleosides
    • Kozak Witold
    • Sebastian Demkowicz
    • Mateusz Daśko
    • Janusz Rachoń
    • Janusz Rak
    2020 Pełny tekst RUSSIAN CHEMICAL REVIEWS

    This review summarizes the state of knowledge on the chemical methods of C(5)-modifications of uridine and cytidine derivatives and may serve as a useful tool for synthetic chemists to choose an appropriate reaction protocol. The synthesis of 5-substituted uracil derivatives is gaining an increasing interest because of their possible applications in medicine and pharmacy. Modifications at the C(5) position of pyrimidine nucleosides can enhance their biostability, bioavailability or(and) biological activity. Among the C(5)-modified nucleosides, 5-halopyrimidines exhibit anticancer, antiviral, radio- and photosensitizing properties. Besides 5-halo-substituted derivatives, there are other examples of nucleosides with confirmed biological activity containing a C7C bond at the C(5) position in the pyrimidine ring. In recent decades, scientists have achieved great progress in the field of cross-coupling reactions. Among them, nickel-catalyzed processes provide a broad spectrum of synthetic methods that are based on less toxic and cheaper starting materials. This review summarizes the synthetic approaches based on the coupling or halogenation reactions, which enable 5-substituted pyrimidine nucleosides to be obtained. Moreover, the importance of the systems considered for medicine and pharmacy is briefly discussed.

  • Modified Manganese Phosphate Conversion Coating on Low-Carbon Steel
    • Jakub Duszczyk
    • Katarzyna Siuzdak
    • Tomasz Klimczuk
    • Judyta Strychalska-Nowak
    • Adriana Zaleska-Medynska
    2020 Pełny tekst Materials

    Conversion coatings are one of the primary types of galvanic coatings used to protect steel structures against corrosion. They are created through chemical reactions between the metal surface and the environment of the phosphating. This paper investigates the impact that the addition of new metal cations to the phosphating reaction environment has on the quality of the final coating. So far, standard phosphate coatings have contained only one primary element, such as zinc in the case of zinc coatings, or two elements, such as manganese and iron in the case of manganese coatings. The structural properties have been determined using a scanning electron microscope (SEM), X-ray diraction (XRD), and electrochemical tests. New manganese coatings were produced through a reaction between the modified phosphating bath and the metal (Ba, Zn, Cd, Mo, Cu, Ce, Sr, and Ca). This change was noticeable in the structure of the produced manganese phosphate crystallites. A destructive eect of molybdenum and chromium was demonstrated. Microscopic analysis, XRD analysis and electrochemical tests suggest that the addition of new metal cations to the phosphating bath aects the corrosion resistance of the modified coating.

  • Moduł platformy SyMEC odpowiedzialny za współpracę serwera MEC z sieciami komórkowymi i bezprzewodowymi sieciami dostępowymi WLAN
    • Michał Hoeft
    • Krzysztof Gierłowski
    • Józef Woźniak
    • Wojciech Gumiński
    • Krzysztof Nowicki
    • Dariusz Więcek
    • Igor Michalski
    • Dariusz Wypiór
    2020 Pełny tekst Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    Zaprezentowano moduł współpracy z sieciami dostępowymi, będący istotnym elementem serwera MEC (Multi-access Edge Computing), budowanego w ramach projektu SyMEC i umożliwiającego uruchamianie elementów aplikacyjnych na brzegu sieci. Przedstawiono różnice w wymaganiach dotyczących sposobu realizacji tego komponentu w przypadku sieci dostępowych standaryzowanych przez 3GPP oraz sieci WLAN. Zaproponowana została architektura umożliwiająca spełnienie powyższych wymagań i ujednolicenie dostępnej funkcjonalności, pomimo zróżnicowanych możliwości oferowanych przez wykorzystywane sieci dostępowe.

  • Molecular Dynamics simulations of thermal conductivity of penta-graphene
    • Isyna Izzal Muna
    • Szymon Winczewski
    2020 Pełny tekst TASK Quarterly

    The thermal conductivity of penta-graphene (PG), a new two dimensional carbon allotrope and its dependence on temperature, strain, and direction are studied in this paper. The thermal conductivity of PG is investigated using a non-equilibrium molecular dynamics simulation (NEMD) with the Two Region Method by applying the optimized Tersoff interatomic potential. Our study shows that the thermal conductivity of PG (determined for the [100] direction) at the room temperature of 300 K is about 18.7 W/(m K), which is much lower than the thermal conductivity of graphene. As the temperature increases, the thermal conductivity of PG is decreasing because, unlike graphene, PG has lower phonon group velocities and few collective phonon excitations. The obtained dependence of the thermal conductivity on the temperature can be described as ∼ −0.32. For the [110] direction the thermal conductivity at the room temperature of 300 K is very similar: about 17.8 W/(m K). In this case, the temperature dependence follows the ∼ −0.3 relation. Our investigations reveal that the thermal conductivity of PG is isotropic, meaning that heat transport behavior is independent of the heat flow direction. Our results indicate that the thermal conductivity of PG depends in an interesting way on the applied strain: nonmonotonic up-and-down behavior is observed. The thermal conductivity increases between strains from 0% up to 12.5%, and it decreases above a strain of 12.5%. Our investigation highlights the fascinating thermal transport properties of penta-graphene. The ultra-low thermal conductivity, the decreasing thermal conductivity with the increasing temperature, and the ultra-high mechanical strength of PG show that PG possesses a great potential in thermoelectric and nanomechanics applications. We hope that these findings, made by means of simulations, will become a bridge to inspire and encourage the experimental works, especially in the synthesis of PG.

  • Molywood: streamlining the design and rendering of molecular movies
    • Miłosz Wieczór
    • Adam Hospital
    • Genis Bayarri
    • Jacek Czub
    • Modesto Orozco
    2020 Pełny tekst BIOINFORMATICS

    Motivation High-quality dynamic visuals are needed at all levels of science communication, from the conference hall to the classroom. As scientific journals embrace new article formats, many key concepts – particularly in structural biology – are also more easily conveyed as videos than still frames. Notwithstanding, the design and rendering of a complex molecular movie remain an arduous task. Here, we introduce Molywood, a robust and intuitive tool that builds on the capabilities of VMD to automate all stages of movie rendering. Results Molywood is a Python-based script that uses an integrated workflow to give maximal flexibility in movie design. It implements the basic concepts of actions, layers, grids and concurrency and requires no programming experience to run. Availability The script is freely available on GitLab (gitlab.com/KomBioMol/molywood) and PyPI (through pip), and features an extended documentation, tutorial and gallery hosted on mmb.irbbarcelona.org/molywood.

  • Moments of Hermite-Gaussian functionals
    • Marek Beśka
    • Mateusz Gałka
    2020 Pełny tekst Applicationes Mathematicae

    Moments of finite products of Hermite-Gaussian functionals are expressed by covariances of Gaussian sequence.

  • Monetary values estimates of solvents emissions
    • Marek Tobiszewski
    • Marta Bystrzanowska
    2020 Pełny tekst GREEN CHEMISTRY

    The impact values for environmental emissions of 52 solvents are estimated and expressed in monetary units. The impact values of solvents present in the air are calculated on the basis of 13 impact indicators and for solvents present in water on additional 2 impact indicators. These impact values are weighted with the results obtained with multi-compartment distribution model, allowing to calculate the fraction of solvent emitted to the environment present in each of the compartments. The results show that the impact values of solvents emissions are in range 0.7 – 1179.06 $ L-1, with mean value 20.69 $ L-1, expressed in USD2019. These impacts are considerably lower for short chain aliphatic hydrocarbons, alcohols, ethers, aldehydes, ketones and esters. High impact values are obtained for long chain aliphatic hydrocarbons, aromatic hydrocarbons, terpenes and extremely high value for carbon tetrachloride. Monetary values calculated to assess the solvents emissions impact have the advantage that they are quantitative, and easily applicable.

  • Monitoring the BTEX Volatiles during 3D Printing with Acrylonitrile Butadiene Styrene (ABS) Using Electronic Nose and Proton Transfer Reaction Mass Spectrometry
    • Wojciech Wojnowski
    • Kaja Kalinowska
    • Jacek Gębicki
    • Bożena Zabiegała
    2020 Pełny tekst SENSORS

    We describe a concept study in which the changes of concentration of benzene, toluene, ethylbenzene, and xylene (BTEX) compounds and styrene within a 3D printer enclosure during printing with different acrylonitrile butadiene styrene (ABS) filaments were monitored in real-time using a proton transfer reaction mass spectrometer and an electronic nose. The quantitative data on the concentration of the BTEX compounds, in particular the concentration of carcinogenic benzene, were then used as reference values for assessing the applicability of an array of low-cost electrochemical sensors in monitoring the exposure of the users of consumer-grade fused deposition modelling 3D printers to potentially harmful volatiles. Using multivariate statistical analysis and machine learning, it was possible to determine whether a set threshold limit value for the concentration of BTEX was exceeded with a 0.96 classification accuracy and within a timeframe of 5 min based on the responses of the chemical sensors.

  • Mono- and bimetallic (Pt/Cu) titanium(IV) oxide photocatalysts. Physicochemical and photocatalytic data of magnetic nanocomposites’ shell
    • Zuzanna Bielan
    • Kowalska Ewa
    • Szymon Dudziak
    • Kunlei Wang
    • Bunsho Ohtani
    • Anna Zielińska-Jurek
    2020 Pełny tekst Data in Brief

    Surface modification of titania with noble and semi-noble metals resulted in significant enhancement of photocatalytic activity. Presented data, showing the photocatalytic properties of TiO2-M (where M is Pt and/or Cu) photocatalysts were further used as Fe3O4@SiO2/TiO2-M magnetic nanocomposites shells in "Mono- and bimetallic (Pt/Cu) titanium(IV) oxide core-shell photocatalysts with Vis light activity and magnetic separability" [1]. Platinum and copper were photodeposited on four different titania matrices (commercial and self-obtained ones). The prepared photocatalysts were characterized by X-ray diffraction (XRD) analysis, specific surface area measurements using the Brunauer-Emmet-Teller (BET) isotherm, diffuse reflectance spectroscopy (DR-UV/Vis) analysis as well as scanning transmission electron microscopy (STEM) analysis. Photocatalytic properties were investigated in three different reactions: H2 generation, acetic acid oxidation to CO2, and phenol degradation.

  • Morze możliwości
    • Karol Moszyk
    • Łukasz Rogatka
    2020 Kaizen

    Z Karolem Moszykiem, Kierownikiem ds. Rozwoju Operacyjnego/ Lean Six Sigma Black Belt, DCT Gdańsk SA i prelegentem pierwszego Gdańskiego Manager Clubu - o ciągłbym doskonaleniu w głębokowodnym terminalu kontenerowym - rozmawiał Łukasz Rogatka

  • Mountain pass solutions to Euler-Lagrange equations with general anisotropic operator
    • Magdalena Chmara
    • Jakub Maksymiuk
    2020 Pełny tekst JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS

    Using the Mountain Pass Theorem we show that the problem \begin{equation*} \begin{cases} \frac{d}{dt}\Lcal_v(t,u(t),\dot u(t))=\Lcal_x(t,u(t),\dot u(t))\quad \text{ for a.e. }t\in[a,b]\\ u(a)=u(b)=0 \end{cases} \end{equation*} has a solution in anisotropic Orlicz-Sobolev space. We consider Lagrangian $\Lcal=F(t,x,v)+V(t,x)+\langle f(t), x\rangle$ with growth conditions determined by anisotropic G-function and some geometric conditions of Ambrosetti-Rabinowitz type.

  • Możliwości wykorzystania spektroskopii fotoelektronów w analizie jakości środowiska wodnego
    • Jacek Ryl
    • Tadeusz Ossowski
    • Maria Elektorowicz
    • Elżbieta Niemirycz
    2020 Technologia Wody

    Spektroskopia fotoelektronów w zakresie promieniowania X, (XPS, z ang. X-ray photoelectron spectroscopy) jest nowoczesną metodą analityczną wykorzystywaną w wielu wiodących ośrodkach naukowych na świecie. Jest ona stale ulepszana, jak też poznawane są nowe obszary jej zastosowania. W niniejszym artykule przedstawione zostały możliwości wykorzystania metody XPS w ramach obszarów badawczych powiązanych z gospodarką wodną, takich jak analiza jakościowa i ilościowa wód oraz osadów dennych, ocena stanu technicznego obiektów i instalacji wodnych oraz badania technik membranowych i bioreaktorów wykorzystywanych w ochronie środowiska wodnego.

  • MP3vec: A Reusable Machine-Constructed Feature Representation for Protein Sequences
    • Sanket Rajan Gupte
    • Dharm Skandh Jain
    • Ashwin Srinivasan
    • Raviprasad Aduri
    2020

    —Machine Learning (ML) methods have been used with varying degrees of success on protein prediction tasks, with two inherent limitations. First, prediction performance often depends upon the features extracted from the proteins. Second, experimental data may be insufficient to construct reliable ML models. Here we introduce MP3vec, a transferable representation for protein sequences that is designed to be used specifically for sequence-to-sequence learning tasks. We use transfer learning to generate the MP3vecs by training a deep neural network on the source problem of protein secondary structure prediction, and then extracting representations learned by the trained network for use in related downstream prediction tasks. ML methods using MP3vecs perform as well as the state-of-the-art (or better) on the target problems, while being orders of magnitude faster in terms of training time. We suggest that MP3vec can act as a strong baseline for comparative work on the use of ML in protein-prediction tasks; and for future extensions with domainspecific features.

  • Multi-agent graph searching and exploration algorithms
    • Dorota Osula
    2020 Pełny tekst

    A team of mobile entities, which we refer to as agents or searchers interchangeably, starting from homebases needs to complete a given task in a graph.The goal is to build a strategy, which allows agents to accomplish their task. We analyze strategies for their effectiveness (e.g., the number of used agents, the total number of performed moves by the agents or the completion time).Currently, the fields of on-line (i.e., agents have no a priori knowledge about the graph topology) multi-agent graph searching and exploration are rapidly expanding. Recent studies have presented new approaches and models to better describe real-life problems like clearing danger areas by a group of robots or constructing a map of an unknown terrain. A centralized searching and exploration in the off-line setting (i.e., when the topology of a graph is known in advance) are well studied, due to their wide applications in robotic and network fields, and many profound results have been established. In this thesis we are focusing on the issues of the monotone connected decontamination problem, the on-line collaborative exploration and the partial exploration of digraphs. Firstly, we provide two comprehensive surveys on the topics of graph searching and exploration. Then in the four subsequent chapters, we present the following results: - We give a distributed algorithm for the searchers that allows them to compute a connected and monotone strategy that guarantees searching any unknown partial grid of order n with the use of O(\sqrt{n}) searchers. Moreover, we give a lower bound of Ω(\sqrt{n}/log n) in terms of achievable competitive ratio of any distributed algorithm. - Checking if the connected pathwidth of any graph is at most some fixed integer k can be done in polynomial time. - Let the cost of a strategy be the total distance traversed by agents coupled with the price of invoking them. We construct two cost-optimal off-line algorithms for rings and trees, respectively. For unknown rings, we give a 2-competitive algorithm. We prove a lower bound of competitive ratio of 3/2 (for rings) and 2 (for trees) for any on-line algorithm. - The problem of establishing if there exists a subgraph, which connects a chosen vertices and can be explored by a given number of agents is NP-hard and FPT.

  • Multicopy Suppressor Analysis of Strains Lacking Cytoplasmic Peptidyl-Prolyl cis/trans Isomerases Identifies Three New PPIase Activities in Escherichia coli That Includes the DksA Transcription Factor
    • Paweł Wojtkiewicz
    • Daria Biernacka
    • Patrycja Gorzelak
    • Anna Stupak
    • Gracjana Klein-Raina
    • Satish Raina
    2020 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Consistent with a role in catalyzing rate-limiting step of protein folding, removal of genes encoding cytoplasmic protein folding catalysts belonging to the family of peptidyl-prolyl cis/trans isomerases (PPIs) in Escherichia coli confers conditional lethality. To address the molecular basis of the essentiality of PPIs, a multicopy suppressor approach revealed that overexpression of genes encoding chaperones (DnaK/J and GroL/S), transcriptional factors (DksA and SrrA), replication proteins Hda/DiaA, asparatokinase MetL, Cmk and acid resistance regulator (AriR) overcome some defects of Δ6ppi strains. Interestingly, viability of Δ6ppi bacteria requires the presence of transcriptional factors DksA, SrrA, Cmk or Hda. DksA, MetL and Cmk are for the first time shown to exhibit PPIase activity in chymotrypsin-coupled and RNase T1 refolding assays and their overexpression also restores growth of a Δ(dnaK/J/tig) strain, revealing their mechanism of suppression. Mutagenesis of DksA identified that D74, F82 and L84 amino acid residues are critical for its PPIase activity and their replacement abrogated multicopy suppression ability. Mutational studies revealed that DksA-mediated suppression of either Δ6ppi or ΔdnaK/J is abolished if GroL/S and RpoE are limiting, or in the absence of either major porin regulatory sensory kinase EnvZ or RNase H, transporter TatC or LepA GTPase or Pi-signaling regulator PhoU.

  • MULTI-CRITERIA COMPARATIVE ANALYSIS OF THE USE OF SUBTRACTIVE AND ADDITIVE TECHNOLOGIES IN THE MANUFACTURING OF OFFSHORE MACHINERY COMPONENTS
    • Mariusz Deja
    • Mieczysław Siemiątkowski
    • Dawid Zieliński
    2020 Pełny tekst Polish Maritime Research

    The dynamic development of additive manufacturing technologies, especially over the last few years, has increased the range of possible industrial applications of 3D printed elements. This is a consequence of the distinct advantages of additive techniques, which include the possibility of improving the mechanical strength of products and shortening lead times. Offshore industry is one of these promising areas for the application of additive manufacturing. This paper presents a decision support method for the manufacturing of offshore equipment components, and compares a standard subtractive method with an additive manufacturing approach. An analytic hierarchy process was applied to select the most effective and efficient production method, considering CNC milling and direct metal laser sintering. A final set of decision criteria that take into account the specifics of the offshore industry sector are provided.

  • Multi-criteria Differential Evolution for Optimization of Virtual Machine Resources in Smart City Cloud
    • Jerzy Balicki
    • Honorata Balicka
    • Piotr Dryja
    • Maciej Tyszka
    2020

    In a smart city, artificial intelligence tools support citizens and urban services. From the user point of view, smart applications should bring computing to the edge of the cloud, closer to citizens with short latency. However, from the cloud designer point of view, the trade-off between cost, energy and time criteria requires the Pareto solutions. Therefore, the proposed multi-criteria differential evolution can optimize virtual machine resources in smart city clouds to find compromises between preferences of citizens and designers. In this class of distributed computer systems, smart mobile devices share computing workload with the set of virtual machines that can be migrated among the nodes of the cloud. Finally, some numerical results are studied for the laboratory cloud GUT-WUT.