2021 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2021

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Safeguarding democracy during pandemics. Social distancing, postal, or internet voting—the good, the bad, or the ugly?
- Robert Krimmer
- David Duenas Cid
- Iuliia Krivonosova
- David Duenas-Cid
2021 Pełny tekst PUBLIC MONEY & MANAGEMENT
During a pandemic, many countries and organizations must decide whether to postpone upcoming elections or to hold them (Krimmer et al., 2020a). If the decision is made to hold the election, three main scenarios come to mind: continue using the existing system but include measures to ensure the health of participants; or look for alternatives among remote voting channels which could ensure social distancing is guaranteed either by postal voting, or internet voting.
Safety and Functionality Assessment of Tram Loops in Wrocław
- Agnieszka Tubis
- Mateusz Rydlewski
- Marcin Budzyński
2021 Pełny tekst Journal of KONBiN
The article presents the implementation of the ISFTL method proposed by the authors consisting in an indicator assessment of the safety and functionality of tram loops. Five tram loops located in Wrocław were analyzed. Each of these loops has different characteristics. The components of each assessment are described in detail and further directions for improving the proposed assessment are indicated.
Safety at railway level crossings and Vision Zero
- Eligiusz Mieloszyk
- Anita Milewska
- Sławomir Grulkowski
2021 Pełny tekst Archives of Civil Engineering
In this work, safety analysis at the railway level crossings is presented using advanced mathematical modelling. Resistivity of track subgrade panels is taken into account. The analysis does not refer to the assessment of the current regulations. Specific cases of generalized dynamic system are considered by introducing operations S=Δ, S=P defined in space C(N) of real sequences. In this model, generalized discrete exponential and trigonometric functions that reflect the oscillatory nature of the analysed quantities are used. The advantage of the analyzes is the avoidance of numerical errors. We show also the importance of the resistivity of track subgrade panels in safety at the level crossings. The safety at the level crossings can be increased through providing track subgrade panels with appropriate resistivity to minimize negative effect of stray currents. The results may be used to evaluate selected safety indicators as well as to predict safety levels and to determine the ways of improving safety.
Samorządy i nauka
- Piotr Wojtulek
- Justyna Płotka-Wasylka
2021 Pełny tekst Forum Akademickie
inansowanie nauki w Polsce powinno dążyć do modelu, w którym są trzy źródła funduszy dla nauki: budżet centralny, budżety samorządów terytorialnych oraz przedsiębiorców. Obecnie zwłaszcza trzecie ze źródeł jest relatywnie słabo zaangażowane w rozwój nauki, być może jest to związane częściowo ze zbytnią dominacją budżetu centralnego w finansowaniu naszej nauki. Z kolei dla samorządów wojewódzkich inwestycje w uczelnie powinny być jednym ze sposobów budowania wysokiej pozycji regionów.
Sample Preparation in Foodomics: Miniaturized Solid-Phase Extraction
- Dorota Garwolińska
- Renata Marcinkowska
- Jacek Namieśnik
- Weronika Hewelt-Belka
2021
Analytical chemists face a challenge to bring comprehensive information on a given food and biological sample by using the best available analytical techniques and meet the requirements of sustainable development and green chemistry at the same time. A key objective of this chapter is to review selected literature data on the utilization of solid-phase extraction techniques with special attention to their miniaturized modes in order to assess the safety, quality and nutritional value of foods. The techniques will be discussed in the context of different samples and analytical information which is about to be obtained.
Satellite Image Classification Using a Hierarchical Ensemble Learning and Correlation Coefficient-Based Gravitational Search Algorithm
- Kowsalya Thiagarajan
- Mukunthan Manapakkam Anandan
- Andrzej Stateczny
- Parameshachari Bidare Divakarachari
- Hemalatha Kivudujogappa Lingappa
2021 Pełny tekst Remote Sensing
Satellite image classification is widely used in various real-time applications, such as the military, geospatial surveys, surveillance and environmental monitoring. Therefore, the effective classification of satellite images is required to improve classification accuracy. In this paper, the combination of Hierarchical Framework and Ensemble Learning (HFEL) and optimal feature selection is proposed for the precise identification of satellite images. The HFEL uses three different types of Convolutional Neural Networks (CNN), namely AlexNet, LeNet-5 and a residual network (ResNet), to extract the appropriate features from images of the hierarchical framework. Additionally, the optimal features from the feature set are extracted using the Correlation Coefficient-Based Gravitational Search Algorithm (CCGSA). Further, the Multi Support Vector Machine (MSVM) is used to classify the satellite images by extracted features from the fully connected layers of the CNN and selected features of the CCGSA. Hence, the combination of HFEL and CCGSA is used to obtain the precise classification over different datasets such as the SAT-4, SAT-6 and Eurosat datasets. The performance of the proposed HFEL–CCGSA is analyzed in terms of accuracy, precision and recall. The experimental results show that the HFEL–CCGSA method provides effective classification over the satellite images. The classification accuracy of the HFEL–CCGSA method is 99.99%, which is high when compared to AlexNet, LeNet-5 and ResNet.
Scaling Up the Process of Titanium Dioxide Nanotube Synthesis and Its Effect on Photoelectrochemical Properties
- Mariusz Szkoda
- Konrad Trzciński
- Zuzanna Zarach
- Daria Roda
- Marcin Łapiński
- Andrzej Nowak
2021 Pełny tekst Materials
In this work, for the first time, the influence of scaling up the process of titanium dioxide nanotube (TiO2NT) synthesis on the photoelectrochemical properties of TiO2 nanotubes is presented. Titanium dioxide nanotubes were obtained on substrates of various sizes: 2 × 2, 4 × 4, 5 × 5, 6 × 6, and 8 × 8 cm2. The electrode material was characterized using scanning electron microscopy as well as Raman and UV–vis spectroscopy in order to investigate their morphology, crystallinity, and absorbance ability, respectively. The obtained electrodes were used as photoanodes for the photoelectrochemical water splitting. The surface analysis was performed, and photocurrent values were determined depending on their place on the sample. Interestingly, the values of the obtained photocurrent densities in the center of each sample were similar and were about 80 µA·cm2. The results of our work show evidence of a significant contribution to wider applications of materials based on TiO2 nanotubes not only in photoelectrochemistry but also in medicine, supercapacitors, and sensors
Scheduling of compatible jobs on parallel machines
- Tytus Pikies
2021
The dissertation discusses the problems of scheduling compatible jobs on parallel machines. Some jobs are incompatible, which is modeled as a binary relation on the set of jobs; the relation is often modeled by an incompatibility graph. We consider two models of machines. The first model, more emphasized in the thesis, is a classical model of scheduling, where each machine does one job at time. The second one is a model of p-batching machines, where a machine can do many jobs at once. Precisely, the jobs have to be grouped into batches and the batches assigned to machines. In the case of the first model, no two jobs that are incompatible can be scheduled on the same machine. In the case of the second one, no two jobs that are incompatible can be scheduled in the same batch. The work analyzes problems of the scheduling with respect to two criteria of optimality, maximum completion time among the jobs and total completion time of jobs. We analyze the problem with the following types of machines: identical, uniform and unrelated. We provide further results for makespan criterion, which is quite commonly considered in the setting of classical machines. More importantly, we provide results for many classes of graphs with respect to the total completion time criterion, which has not been considered in the literature before for the classical machines in the considered setting. In particular, we provide polynomial time algorithms for identical machines; and complete partite graphs or cluster graphs. Also, for complete partite graphs and uniform machines we apply the techniques of rounding, partial exhaustive search, and linear programming to obtain 4-approximate algorithm. The algorithm demonstrates that an application of the techniques to the problems with total completion time criteria is feasible. Finally, there is presented a study of the cost coloring problem, which has direct implications for uniform p-batching machines. Hence, we also briefly consider uniform p-batching machines and weighted total completion time criterion, which is a generalization of total completion time. The study starts with an overview of recent advances in the scheduling algorithms in the context of scheduling incompatible jobs. After the overview, the results presented are: polynomial time algorithms; approximate algorithms with constant approximation ratio; inapproximability results up to some constant, and up to arbitrary constant.
Scheduling with Complete Multipartite Incompatibility Graph on Parallel Machines
- Tytus Pikies
- Krzysztof Turowski
- Marek Kubale
2021
In this paper we consider a problem of job scheduling on parallel machines with a presence of incompatibilities between jobs. The incompatibility relation can be modeled as a complete multipartite graph in which each edge denotes a pair of jobs that cannot be scheduled on the same machine. Our research stems from the works of Bodlaender, Jansen, and Woeginger (1994) and Bodlaender and Jansen (1993). In particular, we pursue the line investigated recently by Mallek, Bendraouche, and Boudhar (2019). We provide several results concerning schedules, optimal or approximate with respect to the two most popular criteria of optimality: Cmax (makespan) and ΣCj (total completion time). We consider a variety of machine types in our paper: identical, uniform, and unrelated. Our results consist of delimitation of the easy (polynomial) and NP-hard problems within these constraints. We also provide algorithms, either polynomial exact algorithms for the easier problems, or algorithms with a guaranteed constant worst-case approximation ratio. In particular, we fill the gap on research for the problem of finding a schedule with the smallest ΣCj on uniform machines. We address this problem by developing a linear programming relaxation technique with an appropriate rounding, which to our knowledge is a novelty for this criterion in the considered setting.
Scheelite-Type Wide-Bandgap ABO4 Compounds (A = Ca, Sr, and Ba; B = Mo and W) as Potential Photocatalysts for Water Treatment
- Marta Kowalkińska
- Paweł Głuchowski
- Tomasz Swebocki
- Tadeusz Ossowski
- Adam Ostrowski
- Waldemar Bednarski
- Jakub Karczewski
- Anna Zielińska-Jurek
2021 Pełny tekst Journal of Physical Chemistry C
In the present study, alkaline-earth metal scheelite-type compounds ABO4 (A = Ca, Sr, Ba, B = Mo, W) synthesized by a hydrothermal method were systematically studied. The as-obtained photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller surface area analysis (BET), UV–Vis diffuse reflectance spectroscopy (DR/UV-Vis), photoluminescence, and thermoluminescence (TL) spectroscopy together with charge carrier’s lifetime measurements, electron paramagnetic resonance spectroscopy (EPR) and electrochemical impedance spectroscopy (EIS). The photocatalytic activity was studied in the reaction of phenol degradation under simulated solar light. The obtained tungstates and molybdates revealed excellent photocatalytic activity despite the low surface area and wide-bandgap typical for insulators. The mechanism of phenol degradation proceeded through hydroquinone and catechol formation in the presence of hydroxyl and superoxide radicals. The presence of electron traps allowed to absorb light with lower energy than resulting from the absorption edge. BaWO4 and SrWO4, with the most extended average carrier lifetime, were the most efficient photocatalysts from obtained series. In general, molybdates exhibited lower photocatalytic activity towards phenol degradation due to deeper trap states and lower average charge carriers' lifetimes than tungstates. Additionally, electrochemical studies emerged that molybdates exhibit more insulating behavior than tungstates. Overall results showed that wide-bandgap semiconductors, mainly tungstates, can be applied as earth-abundant photocatalytic materials for the degradation of persistent organic pollutants.
Searching by heterogeneous agents
- Dariusz Dereniowski
- Łukasz Kuszner
- Robert Ostrowski
2021 JOURNAL OF COMPUTER AND SYSTEM SCIENCES
In this work we introduce and study a pursuit-evasion game in which the search is performed by heterogeneous entities. We incorporate heterogeneity into the classical edge search problem by considering edge-labeled graphs: once a search strategy initially assigns labels to the searchers, each searcher can be only present on an edge of its own label. We prove that this problem is not monotone even for trees and we give instances in which the number of recontamination events is asymptotically quadratic in the tree size. Other negative results regard the NP-completeness of the monotone, and NP-hardness of an arbitrary (i.e., non-monotone) heterogeneous search in trees. These properties show that this problem behaves very differently from the classical edge search. On the other hand, if all edges of a particular label form a (connected) subtree of the input tree, then we show that optimal heterogeneous search strategy can be computed efficiently.
Seasonal and spatial differences in metal and metalloid concentrations in the snow cover of Hansbreen, Svalbard
- Krystyna Kozioł
- Aleksander Uszczyk
- Filip Pawlak
- Marcin Frankowski
- Żaneta Polkowska
2021 Pełny tekst Frontiers in Earth Science
Metals and metalloids in snow on glaciers, depending on the season of deposition, may come from various sources: local rock dust (erosion of the geological substratum), marine aerosol, local human activity (e.g. fuel combustion, waste incineration) and long-range atmospheric transport. Hansbreen glacier, located close to the Polish Polar Station in Svalbard, is a perfect site to study metals and metalloids: it has complex geological substratum, a year-round presence of a small group of people, and is near the coast. We analysed a snapshot of elemental concentrations in snow samples from shallow cores corresponding to autumn, winter and spring deposition on Hansbreen. Eighteen cores of snow were collected across the glacier, revealing the influence of potential local pollution sources. In these samples, we predominantly found Na, Mg and K, followed by Zn, Ca, Al and Fe. Heavy metals (Bi, Hg) were also detected. Cluster analysis of the determined elemental concentrations divided them into three distinct groups: 1) Ag, As, Bi, Cd, Hg, Mo, Sb, Se and Zn – representing mostly long-range transported volatile elements, with possible extra local geological sources; 2) Al, Fe, Cu and Mn – elements with crustal sources, and 3) Na, Ca, Mg, K and Sr – mainly from sea spray aerosol. Such interpretation was confirmed by the calculation of sea salt contribution based on mean seawater composition. In the study site, snow was up to six times more efficient in bringing metal and metalloid pollution into terrestrial environment, when comparared to rain.
Seaweed as a resource for Anaerobic Digestion
- Iwona Cichowska-Kopczyńska
- Robert Aranowski
2021
Extensive growth of algae contributes to disruptive changes to the water ecosystems. This is mainly caused by redundant nutrients that are washed off the land and end up in waters. Tackling eutrophication by recovery of nutrients can be a solution to the problem. Cast marine biomass can be a resource for renewable energy technologies like anaerobic digestion. Such approach can contribute to the transition to a circular bio-economy and to preserving recreational value of the area.
Seaweed utilization issues in biogas production
- Robert Aranowski
- Iwona Cichowska-Kopczyńska
2021
Macroalgae can be seen as a renewable feedstock for the production of biofuels in many coastal areas around the World and especially in Baltic Sea region where the eutrophication is particularly troublesome. The investigation of anaerobic digestion technologies for extracting inexhaustible bioenergy from seaweed was conducted in many research institutions mainly in laboratory scale. Although seaweeds seem to have a great potential as a feedstock in anaerobic digestion due to high biomass yields and lack of competition with terrestrial plants on limited agricultural land, their potentially high heavy metals content and other impurities (like sand and plastics) creates significant problems for the digestion process, but also for the further use of the digestate. Due to high levels of contaminants, it is not always possible to directly use the cast seaweed as a substrate for biogas production. The micro and macro elements uptake by algae strongly depends on factors as water salinity, characteristics of habitats (e.g. presence of an nearby industrial area or existence of an estuary whose waters might carry additional nutrient loads from urban and agriculture areas). The main limiting factor of a digestate utilisation as an organic fertiliser is the heavy metals concentration but the main process issues during anaerobic digestion are caused by the presence of sand in the feedstock. Collected seaweed biomass (especially from sandy beaches) very often contains sand, which can negatively effect the durability of bioreactors and other biogas plant equipment. Pre-treatment of the collected seaweed is essential for the anaerobic digestion process safety and efficient operation of the biogas plant. Furthermore, different stages of pre-treatment as well as the combination of pre-treatment methods can greatly increase the quality of the methane yield. Present study focuses on pre-treatment methods case reducing sand contents in seaweed feedstock.
Secure Italian domination in graphs
- Magda Dettlaff
- Magdalena Lemańska
- Juan A. RODRíGUEZ-VELáZQUEZ
2021 Pełny tekst JOURNAL OF COMBINATORIAL OPTIMIZATION
An Italian dominating function (IDF) on a graph G is a function f:V(G)→{0,1,2} such that for every vertex v with f(v)=0, the total weight of f assigned to the neighbours of v is at least two, i.e., ∑u∈NG(v)f(u)≥2. For any function f:V(G)→{0,1,2} and any pair of adjacent vertices with f(v)=0 and u with f(u)>0, the function fu→v is defined by fu→v(v)=1, fu→v(u)=f(u)−1 and fu→v(x)=f(x) whenever x∈V(G)∖{u,v}. A secure Italian dominating function on a graph G is defined as an IDF f which satisfies that for every vertex v with f(v)=0, there exists a neighbour u with f(u)>0 such that fu→v is an IDF. The weight of f is ω(f)=∑v∈V(G)f(v). The minimum weight among all secure Italian dominating functions on G is the secure Italian domination number of G. This paper is devoted to initiating the study of the secure Italian domination number of a graph. In particular, we prove that the problem of finding this parameter is NP-hard and we obtain general bounds on it. Moreover, for certain classes of graphs, we obtain closed formulas for this novel parameter.
Segmentation Quality Refinement in Large-Scale Medical Image Dataset with Crowd-Sourced Annotations
- Tomasz Dziubich
- Jan Cychnerski
2021
Deployment of different techniques of deep learning including Convolutional Neural Networks (CNN) in image classification systems has accomplished outstanding results. However, the advantages and potential impact of such a system can be completely negated if it does not reach a target accuracy. To achieve high classification accuracy with low variance in medical image classification system, there is needed the large size of the training data set with suitable quality score. This paper presents a study on the use of various consistency checking methods to refine the quality of annotations. It is assumed that tagging was done by volunteers (crowd-sourcing model). The aim of this work was to evaluate the fitness of this approach in the medical field and the usefulness of our innovative web tool designed to facilitate large-scale annotation of magnetic resonance (MR) images, as well as the accuracy of crowd-source assessment using this tool, comparing to expert classification. We present the methodology followed to annotate the collection of kidney MR scans. All of the 156 images were acquired from the Medical University of Gdansk. Two groups of students (with and without medical educational background) and three nephrologists were engaged. This research supports the thesis that some types of MR image annotations provided by naive individuals are omparable to expert annotation, but this process could be shortened in time. Furthermore, it is more costeffective in the simultaneous preservation of image analysis accuracy. With pixel-wise majority voting, it was possible to create crowd-sourced organ segmentations that match the quality of those created by individual medical experts (mAP up to 94% +/-3.9%).
Segmented bio-based polyurethane composites containing powdered cellulose obtained from novel bio-based diisocyanate mixtures
- Ewa Głowińska
- Paulina Kasprzyk
- Janusz Datta
2021 Pełny tekst WOOD SCIENCE AND TECHNOLOGY
A considerable number of research works focus on the positive influence of cellulose on the properties of polymer-based composites and their wide range of application possibilities. The present work is focused on the synthesis of novel bio-based polyurethane (bio-PU) composites filled with powdered cellulose (microcellulose, MC) in an amount of 5 wt.%. Bio-PU composites were synthesized via a non-solvent prepolymer method. First, the prepolymer was synthesized from diisocyanate mixture based on hexamethylene diisocyanate and bio-based polyisocyanate Tolonate™ X Flo 100 and α,ω-oligo(ethylene-butylene adipate)diol which contained cellulose. Then, resulted prepolymer was extended by bio-based 1,4 butanediol (bio-BDO). Bio-PU composites were obtained with the different [NCO]/[OH] molar ratios: 0.95, 1.0, 105 and 1.1. Special attention was paid to the influence of MC on the phase separation between soft and hard segments of bio-PU by studying the chemical structure, morphology and thermal and mechanical properties of the prepared cellulose-based composites.
Seismic damage diagnosis in adjacent steel and RC MRFs considering pounding effects through improved wavelet-based damage-sensitive feature
- Benyamin Mohebi
- Omid Yazdanpanah
- Farzin Kazemi
- Antonio Formisano
2021 Journal of Building Engineering
This paper aims to propose complex Morlet (cmorfb-fc) wavelet-based refined damage-sensitive feature (rDSF) as a new and more precise damage indicator to diagnose seismic damages in adjacent steel and Reinforced Concrete (RC) Moment Resisting Frames (MRFs) assuming pounding conditions using acceleration responses. The considered structures include 6- and 9-story steel and 4- and 8-story RC benchmark MRFs that are assumed to have different values of separation distances, δMT, calculated according to the ASCE 7-10 seismic provision. For the sake of pounding modelling, linear viscoelastic contact elements among the pounding structures are assumed. Furthermore, an algorithm is developed to compute the seismic collapse capacities of each pounding MRF through Incremental Dynamic Analyses (IDA) using OpenSees software. In the next step, auto-regressive movingaverage with exogenous input (ARX) model together with a stabilization diagram is utilized to appraise the natural frequencies of each adjacent MRF. Shannon entropies and correlation coefficient (ρ) are used to select the best cmorfb-fc wavelet. Based on the results, damage resulting from pounding effects can be accurately detected in both cases of with and without δMT, especially for steel MRFs.
Seismic Pounding Between Bridge Segments: A State-of-the-Art Review
- Mahmoud Miari
- Kok Choong
- Robert Jankowski
2021 ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING
Earthquake-induced structural pounding in bridge structures has been observed in several previous seismic events. Collisions occur at the expansion joints provided between adjacent decks or between the deck and abutment. Pounding between the structural elements may lead to severe damages and even to the unseating of the bridge in certain cases. Several investigations have been performed to study pounding in bridges under uniform and non-uniform seismic excitations. Moreover, different mitigation measures have been suggested to overcome the drawbacks of this phenomenon. This work reviews previous research studies concerning earthquake-induced structural pounding in bridge structures, the factors that influence it and the recommended mitigation measures.
Selected Aspects of Pavement Texture Influence on Tire Rolling Resistance
- Jerzy Ejsmont
- Sławomir Sommer
2021 Pełny tekst Coatings
Tire rolling resistance has a significant influence on fuel consumption in cars and trucks and on CO2 emissions. Rolling resistance depends on the tire construction, pavement texture and stiffness, as well as environmental and traffic conditions. This article presents a pilot study on the impact of pavement texture on the rolling resistance of passenger car tires. Reasons why Mean Profile Depth is not a good descriptor of pavement characteristics from the point of view of rolling resistance are presented, and an experimental method which takes into account tire deformation on texture and partial enveloping is described. A method based on testing the volume and depth of tire tread deformation is also proposed.