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  • Researching Digital Society: Using Data-Mining to Identify Relevant Themes from an Open Access Journal
    • Judith Schoßböck
    • Noella Edelmann
    • Nina Rizun
    2021

    Open Access scholarly literature is scientific output free from economic barriers and copyright restrictions. Using a case study approach, data mining methods and qualitative analysis, the scholarly output and the meta-data of the Open Access eJournal of e-Democracy and Open Government during the time interval 2009–2020 was analysed. Our study was able to identify the most prominent research topics (defined as thematic clusters) of the journal, their evolution over time and how these were influenced by journal management factors. This kind of analysis helps editors to develop an editorial strategy, decide on the thematic development of the journal and address the expectations of future authors of the journal. It further can provide insights about research themes and trends within a scholarly community and their development over time.

  • Researching Digital Society: Using Data-Mining to Identify Relevant Themes from an Open Access Journal
    • Judith Schoßböck
    • Noella Edelmann
    • Nina Rizun
    2021 Full text

    Open Access scholarly literature is scientific output free from economic barriers and copyright restrictions. Using a case study approach, data mining methods and qualitative analysis, the scholarly output and the meta-data of the Open Access eJournal of e-Democracy and Open Government during the time interval 2009–2020 was analysed. Our study was able to identify the most prominent research topics (defined as thematic clusters) of the journal, their evolution over time and how these were influenced by journal management factors. This kind of analysis helps editors to develop an editorial strategy, decide on the thematic development of the journal and address the expectations of future authors of the journal. It further can provide insights about research themes and trends within a scholarly community and their development over time

  • Reshaping financial systems: The role of ICT in the diffusion of financial innovations – Recent evidence from European countries
    • Ewa Lechman
    • Adam Marszk
    2021 Full text TECHNOLOGICAL FORECASTING AND SOCIAL CHANGE

    Exchange-traded funds (ETFs) are among the fastest-growing types of innovative financial products. The emergence and spread of these instruments have been facilitated by the digital revolution. Information and communication technology (ICT) is profoundly reshaping the global economic landscape, laying solid foundations for unrestricted and unbounded flows of information and knowledge, eliminating information asymmetries, and furthering the rapid diffusion of financial innovations worldwide. This work contributes to the literature by exploring the linkages between variations in ICT penetration and the development and expansion of financial innovation on stock exchanges in ten European countries: France, Germany, Hungary, Italy, Norway, Poland, Spain, Switzerland, Turkey, and the United Kingdom. The analysis covers the period from 2004 to 2019, and uses panel and country-specific regression models to verify the relationship hypothesized between increasing ICT penetration and the development of exchange-traded funds. Our findings indicate that ICT spreads evenly in all the countries, laying solid foundations for the development of innovative financial products. We also find that ICT positively influences the diffusion of ETFs, regardless of the other possible determinants considered; however, despite the high level of ICT adoption in most of the economies analyzed, ETF market development has not been universal, with substantial between-country differences.

  • Reshaping the Gdańsk Shipyard—The Birthplace of the Solidarity Movement. The Complexity of Adaptive Reuse in the Heritage Context
    • Piotr Lorens
    • Łukasz Bugalski
    2021 Full text Sustainability

    The Gdańsk Shipyard—the birthplace of the Solidarity movement—is host to a unique example of a multi-layered brownfield redevelopment project, an area that is burdened by a complex history, overlapping heritage, and multiple memories. These circumstances require an integrated yet differentiated approach to the site’s heritage and make the creation of one homogeneous narration of its future impossible. At the same time, the size of the area, as well as its location within Gdańsk city centre, has meant that its future has been the subject of numerous discussions and speculations conducted over the last 20 years—starting from the creation of a large-scale open-air museum and continuing to the localization of the new Central Business District of the city. Consequently, that broad discussion carried out regarding the scope of redevelopment projects has been rooted in the possible introduction of diverse models of adaptive reuse. This variety of possible approaches also includes discussion on the mode of integrating heritage in the redevelopment processes. The goal of this paper—written just before the initiation of the final stage of the conceptual part of the project—is to present the complexity of approaches to issues related to redevelopment and heritage preservation.

  • Revalorisation of the Szewalski’s concept of the law of varying the last-stage blade retraction in a gas-steam turbine
    • Paweł Ziółkowski
    • Stanisław Głuch
    • Tomasz Kowalczyk
    • Janusz Badur
    2021 Full text E3S Web of Conferences

    The article presents the implementations of the free vortex law to the blade of the last stage of a gas-steam turbine. First, a thermodynamic analysis was carried out, determining the parameters at the inlet, then the number of stages of the high and low-pressure part of the turbine was constructed, together with the kinematics and velocity vectors for subsequent stages of the axial turbine. The last step of article was to take into account the law of variation of the peripheral component of the velocity of the medium working with the radius of the turbine in a discrete way and to make a 3D drawing of the resulting geometry. When creating the spatial model, the atlas of profiles of reaction turbine stages was used.

  • Revealing dynamic changes of the volatile profile of food samples using PTR–MS
    • Tomasz Majchrzak
    • Wojciech Wojnowski
    • Andrzej Wasik
    2021 FOOD CHEMISTRY

    Volatile compounds carry valuable information regarding the properties of foodstuffs. Volatiles emitted from food can be used as, for example, indicators of quality, shelf-life, or authenticity. A better understanding of the multitude of transformations which occur during food processing could facilitate the optimisation of production, increase the desirability of food products, and also their wholesomeness. However, as some of these transformations are fast-paced, it is necessary to monitor them using techniques which enable real-time determination of volatiles, such as proton transfer reaction–mass spectrometry (PTR–MS). Recent years have seen a marked increase in its use in food analysis, since it can be used to obtain insight into the dynamics of the monitored processes and can be the basis for precise quality control methods for food processing. This review highlights recent works in which PTR–MS was used in monitoring during foodstuffs production, preparation and storage.

  • Revealing the Frank–Evans “Iceberg” Structures within the Solvation Layer around Hydrophobic Solutes
    • Joanna Grabowska
    • Anna Kuffel
    • Jan Zielkiewicz
    2021 Full text JOURNAL OF PHYSICAL CHEMISTRY B

    Using computer simulations, the structural properties of solvation water of three model hydrophobic molecules, methane and two fullerenes (C60 and C80), were studied. Systems were simulated at temperatures in the range of 250−298 K. By analyzing both the local ordering of the molecules of water in the solvation layers and the structure of hydrogen bond network, it is shown that in the solvation layer of hydrophobic molecules, ordered aggregates consisting of water molecules are formed. Even though it is difficult to define the exact structure of these aggregates, their existence alone is clearly noticeable. Moreover, these aggregates become more pronounced with the decrease of temperature. The existence of the ordered aggregates around the hydrophobic solutes complies with the concept of “icebergs” proposed by Frank and Evans.

  • Reversible Data Hiding in Encrypted DICOM Images Using Cyclic Binary Golay (23, 12) Code
    • Mariusz Dzwonkowski
    • Roman Rykaczewski
    2021 Full text IEEE Access

    In this paper, a novel reversible data hiding method for encrypted images (RDHEI) is proposed. An efficient coding scheme based on cyclic binary Golay (23, 12) code is designed to embed additional data into the least significant bits (LSBs) of the encrypted image. The most significant bits (MSBs) are used to ensure the reversibility of the embedding process. The proposed scheme is lossless, and based on the receiver’s privileges, allows recovery of marked data, original data and embedded data. Furthermore, the scheme can be used with any type of data, however it is best suited to 16-bit DICOM images of monochrome photometric interpretation. A modification to the standard DICOM network model was also introduced, to point out an example application of the proposed RDHEI method, i.e. an anonymized data storage outsourcing. A computer-based analysis has been carried out and simulation results are shown at the end of this paper.

  • Review of Cybersecurity Assessment Methods: Applicability Perspective
    • Rafał Leszczyna
    2021 Full text COMPUTERS & SECURITY

    Cybersecurity assessments are crucial in building the assurance that vital cyberassets are effectively protected from threats. Multiple assessment methods have been proposed during the decades of the cybersecurity field. However, a systematic literature search described in this paper reveals that their reviews are practically missing. Thus, the primary objective of this research was to fulfil this gap by comprehensively identifying and analysing cybersecurity assessment methods described in the scientific literature. A structured research method and transparent criteria were applied for this purpose. As a result, thirty-two methods are presented in this paper. Particular attention is paid to the question of the methods’ applicability in realistic contexts and environments. In that regard, the challenges and limitations associated with the methods’ application as well as potential approaches to addressing them have been indicated. Besides, the paper systematises the terminology and indicates complementary studies which can be helpful during assessments. Finally, the areas that leave space for improvement and directions for further research and development are indicated. The intention is to support researchers and practitioners in choosing the method to be applied in their assessments and to indicate the areas that can be further explored.

  • Review of International Standards and Policy Guidelines for Smart Sustainable Cities
    • Elsa Estevez
    • Karina Cenci
    • Pablo Fillottrani
    • Tomasz Janowski
    2021 Full text

    Smart cities are often criticized for preoccupation with technology, for ignoring the negative effects of technology, for irrelevance to the needs of the poor, and for ubiquitous data collection creating perfect conditions for surveillance societies and autocratic states. In response, cities pursue smartness and sustainability simultaneously, becoming global (by participation in global digital networks) and local (by addressing local needs and circumstances) at the same time. In the pursuit of smart sustainable cities, they make explicit policy decisions about how technology should serve their residents, businesses and visitors, and avoid disrupting them. Many decisions are about standards—which standards should be followed and how, and increasingly, standards and policy guidelines are adopted by cities from international organizations, circumventing national authorities. This chapter reviews international standards and policy guidelines published by international standards organizations or intergovernmental bodies, with stated goals to support member states in the development and management of smart sustainable cities. We conducted the review through exploratory research and comparative policy analysis. The result could be used to raise awareness and address knowledge needs among city managers, policy analysts, and smart city researchers.

  • Review of Selected Methods for Prediction of Added Resistance in Following Waves
    • Sebastian Bielicki
    • Michał Kalbarczyk
    2021

    The added resistance in waves is a mean value of non-linear, second order reaction of a ship to incoming waves. In the beginning of the 20th century, the experimental methods for investigation of ship hydrodynamics at model scale were developed. They allowed the evaluation of added resistance by measurements in irregular waves (directly) or by measurements in regular waves (in-direct method). The main goal was to find more precise information about the margin for on-board installed engine power to fulfill operational demands of designed vessel. In the early sixties of the 20th century, numerical methods appeared, enabling the seakeeping analyses in frequency domain, and including the methods for determination of added resistance due to head waves. These computational methods, based on gravity character of added resistance, applied the potential flow theory and were mainly determined to cope with head waves. However, the issue of route optimization as well as the phenomena of broaching and surf-riding of vessels going through following and aft-quartering waves gained more attention recently, what demands accurate prediction methods applicable also for these conditions. To avoid dangerous behavior of a vessel, it is necessary to increase the speed, which means that the ship has to maintain a power margin for this operation. The level of added power can be assessed basing on computations of added resistance in waves coming from mentioned directions. The following paper presents the comparison of the results obtained from selected computational methods, including potential methods, semi-empirical formulae and RANS-CFD, with results of dedicated model experiments.

  • Review of Sustainability Assessment Tools for Buildings and Cities
    • Gulben Calis
    • Dorota Kamrowska-Załuska
    • Ezgi Kocaman
    • Merve Kuru
    2021

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  • Review on robust laser light interaction with titania – Patterning, crystallisation and ablation processes
    • Katarzyna Siuzdak
    • Łukasz Haryński
    • Jakub Wawrzyniak
    • Katarzyna Grochowska
    2021 PROGRESS IN SOLID STATE CHEMISTRY

    Titanium dioxide is regarded as a very promising semiconducting material that is widely applied in many everyday-use products, devices, and processes. In general, those applications can be divided into energy or environmental categories, where a high conversion rate, and energy and power density are of particular interest. Therefore, many efforts are being put towards the elaboration of novel production routes, and improving the material's properties such as light absorption, and charge concentration, as well as development of the surface area to improve the efficiency of particular process. Typically, bulk doping and surface modifications can be distinguished, applying some sol-gel, chemical vapour deposition, and hydrothermal processes in the presence of dopant precursors. However, development of waste disposal and many up-scaling optimisation routes have to be performed to consider the proposed path worthy of wide scale, commercial use. In contrast to the wet-chemistry methods, laser technology offers unique material treatment by light of a particular wavelength, fluence, and pulse repetition rate. In consequence, the changes can affect the bulk structure or only its surface. Such an approach provides a wide range of possible modifications without the use of any chemical products, and therefore avoids the formation of any by-products. Moreover, knowing the facile scaling up of laser treatment towards a higher technology readiness level, we believe such an approach stands out from synthesis and/or modification carried out first in small flasks and using small amounts of substrates. In this review, we would like to emphasize the results of selected studies presenting possible laser beam and titania interactions ensuring changes in the surface zone or deeply in the internal structure. The works evoked here indicate that this powerful technique can, among other things, provide slight surface melting of titania nanotubes, their phase transition from an amorphous solid to anatase or, when the fluence exceeds a certain threshold, the ablation of material out of the titania target.

  • Reviewing the recent developments of using graphene-based nanosized materials in membrane separations
    • Roberto Castro-Muñoz
    • Angélica Cruz-Cruz
    • Yrenka Alfaro-Sommers
    • Luisa Ximena Aranda-Jarillo
    • Emilia Gontarek-Castro
    2021 CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY

    According to the potentialities of graphene-based materials and their unique physicochemical properties. Such 2D nanomaterials are likely to be the most implemented within the improvement of the selective separations of polymer membranes, together with enhanced physicochemical properties (such as hydrophilicity/hydrophobicity, transport of molecules, mechanical and thermal features, among others). Hence, this review compiles and analyzes the latest development works (over the last 5 years) for combining graphene materials (including graphene oxide, reduced graphene oxide, etc.) in polymer phases at aiming their implementation in different membrane-based technologies. Herein, particular emphasis has been crucially paid to the novel studies together with relevant findings in the field. Based on the most important insights, the concluding remarks are given with compelling recommendations to the new researchers at exploring graphene materials in membrane separations.

  • Revitalization of Residential Buildings Dating Back to the Late19th and Early 20th Century on the Example of “Willa Halina” in Sopot (Poland)
    • Antoni Taraszkiewicz
    2021 Full text Buildings

    Residential buildings dating back to the late 19th and early 20th century constitute an important element of the urban composition of many European cities, often determining their overall spatial expression. These buildings often require revitalization and sometimes also reconstruction or extension. Such activities make it possible to restore historical buildings to their former glory, but also to create new architecture, inscribed in the context of the place, yet bearing witness to modern times. Revitalization of historically and architecturally valuable but technically degraded residential buildings is one of the important elements of maintaining and sometimes rebuilding the image of modern cities and their sustainable development. However, revitalization activities require solving many problems of conservational nature, especially issues related to preserving the authenticity of the existing tissue, ways of reconstructing lost elements, and connecting historical architecture with contemporary architecture. Historic residential buildings of Sopot, a city located in Poland on the shores of the Baltic Sea, dating back to the late 19th and early 20th century, provide excellent research material for such considerations. In the article, the historical center of Sopot was examined, with particular emphasis on the historic Willa Halina from 1896 located there, which was revitalized (according to the design of the author of the article). Using such research methods as analysis of historical source material (iconography), observation (operationalization of preserved historical objects), comparative analysis of contemporary investments, and analysis of the revitalization design of “Willa Halina”, an attempt was made to present spatial and technical solutions leading to the desired effects in the revitalization process. This work aims to show (on the example of Willa Halina in Sopot) the author’s method of revitalizing valuable, historical residential buildings, complying with international conservation standards, including the Venice Charter, adopted in 1964 by the Second International Congress of Architects and Technicians of Historical Monuments. The paper also aims to present spatial and technical solutions leading to desired effects in the revitalization process, consistent with the idea of sustainable development.

  • Rewitalizacja posadzek betonowych typu lastrico w obiektach zabytkowych. Część 1
    • Sylwia Świątek-Żołyńska
    • Maciej Niedostatkiewicz
    • Władysław Ryżyński
    2021 Full text Builder

    W artykule przedstawiono zagadnienia materiałowe i technologiczne dotyczące posadzek typu lastrico w aspekcie oceny ich stanu technicznegooraz sposobów naprawy i rewitalizacji.

  • Rewitalizacja posadzek betonowych typu lastrico w obiektach zabytkowych. Część 2
    • Sylwia Świątek-Żołyńska
    • Maciej Niedostatkiewicz
    • Władysław Ryżyński
    2021 Full text Builder

    W artykule przedstawiono zagadnienia materiałowe i technologiczne dotyczące posadzek typu lastrico w aspekcie oceny ich stanu technicznego oraz sposobów naprawy i rewitalizacji. Tekst stanowi kontynuacje artykułu zamieszczonego w Builder Science3 nr 9/2021

  • Ring Opening of Triflates Derived from Benzophospholan-3-one Oxides by Aryl Grignard Reagents as a Route to 2‑Ethynylphenyl(diaryl)phosphine Oxides
    • Łukasz Ponikiewski
    • Sylwia Sowa
    2021 Full text JOURNAL OF ORGANIC CHEMISTRY

    A new simple method for the synthesis of 2-ethynylphenyl(diaryl)phosphine oxides via ring opening of benzophosphol-3-yl triflates has been developed. This process occurs via nucleophilic attack of a Grignard reagent at the phosphorus center, which results in ring opening and cleavage of a leaving group. The reaction proceeds under mild conditions and, within 15−60 min, leads to a library of previously unavailable 2-ethynylphenylphosphine oxides in yields up to 98%.

  • Risk Analysis by a Probabilistic Model of the Measurement Process
    • Wojciech Toczek
    • Janusz Smulko
    2021 Full text SENSORS

    The aim of the article is presentation of the testing methodology and results of examination the probabilistic model of the measurement process. The case study concerns the determination of the risk of an incorrect decision in the assessment of the compliance of products by measurement. Measurand is characterized by the generalized Rayleigh distribution. The model of the meas-urement process was tested in parallel mode by six risk metrics. An undesirable effect in the re-construction building block of the model was detected, consisting in the distortion of probability distribution at the edges of the measuring range. The paper gives guidelines on how to use the model, to obtain the analytical risk assessment consistent with the results of the Monte Carlo method. The study can be useful in product quality control, test design, and fault diagnosis.

  • Risk assessment for tram traffic on tramway bridges
    • Kazimierz Jamroz
    • Sławomir Grulkowski
    • Krystian Birr
    • Łukasz Jeliński
    • Marcin Budzyński
    2021 Full text Archives of Civil Engineering

    Miejski transport szynowy wielu miastach stanowi istotny element systemu transportowego i jest przestrzennie rozwijającym się systemem zapewniającym mieszkańcom codzienną obsługę transportową. Bezpieczeństwo pasażerów transportu szynowego i użytkowników dróg jest jednym z najważniejszych czynników, który należy uwzględnić w trakcie projektowania infrastruktury oraz w ocenie operacyjnej systemu miejskiego transportu tramwajowego. Jedną z nierozwiązanych kwestii funkcjonowania transportu tramwajowego są odcinki dróg tramwajowych o dużych pochyleniach podłużnych. W artykule przedstawiono próbę zastosowania metody zarządzania ryzkiem do oceny bezpieczeństwa funkcjonowania dróg tramwajowych na obiektach zlokalizowanych na odcinkach dróg o dużych pochyleniach podłużnych. Taki problem występuje na trasie tramwajowej w Gdańsku przebiegającej na ulicy (częściowo na estakadzie) o pochyleniu położonej powyżej 5 % i małym łuku poziomym. Do oceny ryzyka zastosowano metodę zarządzania ryzykiem w transporcie TRANS-RISK. W pierwszym etapie przeprowadzono analizę ryzyka zagrożeń, korzystając z metod Bow-Tie i drzewa błędów zidentyfikowano główne zagrożenia poważnymi wypadkami na analizowanym odcinku drogi tramwajowej. Do oceny ryzyka zastosowano trzy podejścia oceniając ryzyko: indywidualne, społeczne i kolektywne. To ostatnie, nie używane w tego typu ocenach miejskiej infrastruktury transportowej, okazało się najbardziej przydatne do oceny bezpieczeństwa analizowanej infrastruktury. Wyniki przeprowadzonych analiz i ocen pozwoliły na sformułowanie zasad projektowania i utrzymania obiektów infrastruktury tramwajowej położonej na odcinkach o dużych pochyleniach.

  • ROAD SAFETY FOR CYCLISTS BASED ON THE CALORIES NEEDED
    • Gaetano Bosurgi
    • Orazio Pellegrino
    • Joanna Wachnicka
    • Romanika Okraszewska
    2021 Full text Transport Problems

    Cyclists are a vulnerable group of road users, especially when no separate infrastructure for cyclists is provided. Then, road factors such as distance and altitude differences can indirectly affect cyclists' safety. Therefore, the authors proposed a procedure based on the geometric characteristics of the road that can determine riding difficulties for cyclists. The proposed procedure can be used both by the public authorities who manage cyclists' safety and as a method of classifying the road network for cycling. The proposed procedure, based on the use of pattern recognition techniques, analyses data from a sample of nine riders who travelled on rural roads within the Municipality of Messina (Italy) to classify the roads according to their cycling difficulty. For each rider, duration, distance, road slope, altitude difference and spent calories have been measured and analysed. The collected data were used for the development of a model capable of predicting the cyclist’s physical effort as a function of the road alignment itself. Knowing the effort required to cycle along a route can contribute to a more complete assessment of road classification, commonly defined according to motor vehicles. Moreover, it may constitute a measure determining the safety of cycling by encouraging cyclists to travel along roads compatible with their physical abilities.

  • Roadmap on dynamics of molecules and clusters in the gas phase
    • Henning Zettergren
    • Alicja Domaracka
    • Thomas Schlathölter
    • Paola Bolognesi
    • Sergio Díaz-Tendero
    • Marta Łabuda
    • Sanja Tosic
    • Sylvain Maclot
    • Per Johnsson
    • Amanda Steber
    • Denis Tikhonov
    • Mattea Carmen Castrovilli
    • Lorenzo Avaldi
    • Sadia Bari
    • Aleksandar Milosavljević
    • Alicia Palacios
    • Shirin Faraji
    • Dariusz G. Piekarski
    • Patrick Rousseau
    • Daniela Ascenzi
    • Claire Romanzin
    • Ewa Erdmann
    • Manuel Alcamí
    • Janina Kopyra
    • Paulo Limão-Vieira
    • Jaroslav Kočišek
    • Juraj Fedor
    • Simon Albertini
    • Michael Gatchell
    • Henrik Cederquist
    • Henning T. Schmidt
    • Elisabeth Gruber
    • Lars H. Andersen
    • Oded Heber
    • Yoni Toker
    • Klavs Hansen
    • Jennifer A. Noble
    • Christophe Jouvet
    • Christina Kjær
    • Steen Nielsen
    • Eduardo Carrascosa
    • James Bull
    • Alessandra Candian
    • Annemieke Petrignani
    2021 Full text EUROPEAN PHYSICAL JOURNAL D

    This roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics of molecules and clusters in the gas phase. It comprises nineteen contributions by scientists with leading expertise in complementary experimental and theoretical techniques to probe the dynamics on timescales spanning twenty orders of magnitudes, from attoseconds to minutes and beyond, and for systems ranging in complexity from the smallest (diatomic) molecules to clusters and nanoparticles. Combining some of these techniques open up new avenues to unravel hitherto unexplored reaction pathways and mechanisms, and to establish their significance in, e.g. radiotherapy and radiation damage on the nanoscale, astrophysics, astrochemistry, and atmospheric science.

  • Robot-Based Intervention for Children With Autism Spectrum Disorder: A Systematic Literature Review
    • Katrin D. Bartl-Pokorny
    • Pinar Uluer
    • Duygun Erol Barkana
    • Alice Baird
    • Hatice Kose
    • Tatjana Zorcec
    • Ben Robins
    • Bjorn Schuller
    • Agnieszka Landowska
    • Małgorzata Pykała
    2021 Full text IEEE Access

    Children with autism spectrum disorder (ASD) have deficits in the socio-communicative domain and frequently face severe difficulties in the recognition and expression of emotions. Existing literature suggested that children with ASD benefit from robot-based interventions. However, studies varied considerably in participant characteristics, applied robots, and trained skills. Here, we reviewed robot-based interventions targeting emotion-related skills for children with ASD following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We systematically searched for all relevant articles published in English language until May 2021, using the databases Scopus, Web of Science, and PubMed. From a total of 609 identified papers, 60 publications including 50 original articles and 10 non-empirical articles including review articles and theoretical articles were eligible for the synthesis. A total of 892 participants were included in the robot-based intervention studies; 570 of them were children with ASD. Nao and ZECA were the most frequently used robots; recognition of basic emotions and getting into interaction were the most frequently trained skills, while happiness, sadness, fear, and anger were the most frequently trained emotions. The studies reported a wide range of challenges with respect to robot-based intervention, ranging from limitations for certain ASD subgroups and security aspects of the robots to efforts regarding the automatic recognition of the children’s emotional state by the robotic systems. Finally, we summarised and discussed recommendations regarding the application of robot-based interventions for children with ASD.

  • Robust Parameter Tuning of Antenna Structures by Means of Design Specification Adaptation
    • Sławomir Kozieł
    • Wacław Pietrenko
    2021 Full text IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    Parameter tuning through numerical optimization has become instrumental in the design of high-performance antenna systems. Yet, practical optimization faces several major challenges, including high cost of massive evaluations of antenna characteristics, normally involving full-wave electromagnetic (EM) analysis, large numbers of adjustable variables, the shortage of reasonable initial solutions in the case of topologically complex structures, and multimodality of the objective function landscapes. The last two reasons foster the employment of global search routines, which might be prohibitively expensive. This paper proposes a novel procedure for efficient and reliable antenna optimization by means of design specification adaptation. By using appropriate selection criteria and the predictions from a linear expansion model, the ability of improving the current design is verified, and—in the case of a negative outcome—performance requirements are relaxed temporarily. The adjustment is carried out before each iteration of the optimization process with the specifications eventually converging to their original levels. The algorithm is intended to improve the efficacy of local optimizers if the target operating frequencies of the structure at hand are severely misaligned with respect to those at the available initial design. This eliminates the need for global routines, and greatly enhances the robustness of the search process, as demonstrated using several antenna structures optimized under different scenarios.

  • Robust-adaptive dynamic programming-based time-delay control of autonomous ships under stochastic disturbances using an actor-critic learning algorithm
    • Hossein Nejatbakhsh Esfahani
    • Rafał Szłapczyński
    2021 Full text JOURNAL OF MARINE SCIENCE AND TECHNOLOGY

    This paper proposes a hybrid robust-adaptive learning-based control scheme based on Approximate Dynamic Programming (ADP) for the tracking control of autonomous ship maneuvering. We adopt a Time-Delay Control (TDC) approach, which is known as a simple, practical, model free and roughly robust strategy, combined with an Actor-Critic Approximate Dynamic Programming (ACADP) algorithm as an adaptive part in the proposed hybrid control algorithm. Based on this integration, Actor-Critic Time-Delay Control (AC-TDC) is proposed. It offers a high-performance robust-adaptive control approach for path following of autonomous ships under deterministic and stochastic disturbances induced by the winds, waves, and ocean currents. Computer simulations have been conducted under two different conditions in terms of the deterministic and stochastic disturbances and all simulation results indicate an acceptable performance in tracking of paths for the proposed control algorithm in comparison with the conventional TDC approach.

  • Robustness Analysis of a Distributed MPC Control System of a Turbo-Generator Set of a Nuclear Plant – Disturbance Issues
    • Paweł Sokólski
    • Tomasz Rutkowski
    • Bartosz Ceran
    • Dariusz Horla
    2021 Full text Advances in Intelligent Systems and Computing

    Typically, there are two main control loops with PI controllers operating at each turbo-generator set. In this paper, a distributed model predictive controller with local quadratic model predictive controllers for the turbine generator is proposed instead of a set of classical PI controllers. The local quadratic predictive controllers utilize step-response models for the controlled system components. The parameters of these models are determined based on the proposed black-box models of the turbine and synchronous generator, which parameters are identified on-line with the recursive least-squares algorithm. A robustness analysis of the control system with respect to different disturbances is presented in the paper. There are various configurations considered, such as change in disturbance levels from the side of electrical and thermal systems, or changes in prediction horizons.

  • Robustness in Compressed Neural Networks for Object Detection
    • Sebastian Cygert
    • Andrzej Czyżewski
    2021 Full text

    Model compression techniques allow to significantly reduce the computational cost associated with data processing by deep neural networks with only a minor decrease in average accuracy. Simultaneously, reducing the model size may have a large effect on noisy cases or objects belonging to less frequent classes. It is a crucial problem from the perspective of the models' safety, especially for object detection in the autonomous driving setting, which is considered in this work. It was shown in the paper that the sensitivity of compressed models to different distortion types is nuanced, and some of the corruptions are heavily impacted by the compression methods (i.e., additive noise), while others (blur effect) are only slightly affected. A common way to improve the robustness of models is to use data augmentation, which was confirmed to positively affect models' robustness, also for highly compressed models. It was further shown that while data imbalance methods brought only a slight increase in accuracy for the baseline model (without compression), the impact was more striking at higher compression rates for the structured pruning. Finally, methods for handling data imbalance brought a significant improvement of the pruned models' worst-detected class accuracy.

  • Rola i techniki eksploracji w uczeniu przez wzmacnianie
    • Piotr Januszewski
    2021

    W rozdziale podjęto rozważania na temat roli eksploracji w uczeniu się agentów sztucznej inteligencji przez wzmacnianie. Prezentuje przegląd współczesnych technik eksploracji i rozróżnia dwie główne rodziny technik: eksplorację nieukierunkowaną i eksplorację ukierunkowaną. Praca ta powinna pomóc zrozumieć dylemat pomiędzy eksploatacją wiedzy a eksploracją środowiska, któremu poddany jest agent w każdym kroku interakcji ze środowiskiem. Opisane tutaj techniki mogą być inspiracją do dalszych prac nad rozwiązaniem tego dylematu i tym samym ulepszenia metod uczenia się przez wzmacnianie.

  • Role of cholesterol in substrate recognition by -secretase
    • Łukasz Nierzwicki
    • Michał Olewniczak
    • Paweł Chodnicki
    • Jacek Czub
    2021 Full text Scientific Reports

    -Secretase is an enzyme known to cleave multiple substrates within their transmembrane domains, with the amyloid precursor protein of Alzheimer’s Disease among the most prominent examples. The activity of -secretase strictly depends on the membrane cholesterol content, yet the mechanistic role of cholesterol in the substrate binding and cleavage remains unclear. In this work, we used all-atom molecular dynamics simulations to examine the role of cholesterol in the initial binding of a direct precursor of -amyloid polypeptides by -secretase. We showed that in cholesterol-rich membranes, both the substrate and the enzyme region proximal to the active site induce a local membrane thinning. With the free energy methods we found that in the presence of cholesterol the substrate binds favorably to the identified exosite, while cholesterol depletion completely abolishes the binding. To explain these findings, we directly examined the role of hydrophobic mismatch in the substrate binding to -secretase, showing that increased membrane thickness results in higher propensity of the enzyme to bind substrates. Therefore, we propose that cholesterol promotes substrate binding to -secretase by increasing the membrane thickness, which leads to the negative hydrophobic mismatch between the membrane and binding partners.

  • Room temperature depinning of the charge-density waves in quasi-two-dimensional 1T-TaS2 devices
    • A. Mohammadzadeh
    • A. Rehman
    • F. Kargar
    • S. Rumyantsev
    • Janusz Smulko
    • W. Knap
    • R. K. Lake
    • A. A. Balandin
    2021 Full text APPLIED PHYSICS LETTERS

    We report on the depinning of nearly commensurate charge-density waves in 1T-TaS2 thin films at room temperature. A combination of the differential current–voltage measurements with the low-frequency noise spectroscopy provides unambiguous means for detecting the depinning threshold field in quasi-2D materials. The depinning process in 1T-TaS2 is not accompanied by an observable abrupt increase in electric current—in striking contrast to depinning in the conventional charge-density-wave materials with quasi-1D crystal structure. We explained it by the fact that the current density from the charge-density waves in the 1T-TaS2 devices is orders of magnitude smaller than the current density of the free carriers available in the discommensuration network surrounding the commensurate charge-density wave islands. The depinning fields in 1T-TaS2 thin-film devices are several orders of magnitude larger than those in quasi-1D van der Waals materials. Obtained results are important for the proposed applications of the charge-density wave devices in electronics.

  • Rozwój systemu finansowego Polski w gospodarce globalnej
    • Karolina Tura-Gawron
    • Adam Marszk
    2021

    Temat niniejszej monografii to powstanie oraz rozwój systemu finansowego w Polsce od rozpoczęcia transformacji ustrojowej, ze szczególnym uwzględnieniem miejsca Polski w globalnej gospodarce. Istotną częścią monografii są przesłanki i wytyczne dotyczące możliwych przyszłych rozwiązań oraz kierunków ewolucji polskiego systemu finansowego, wyprowadzone na podstawie wykonanych przez autorów badań i analiz polskiej/ globalnej gospodarki. Cele główne monografii: - przedstawienie oraz ocena zmian, które zaszły w polskim systemie finansowym po 1989 roku, od kiedy Polska stała się w pełni częścią globalnej gospodarki; - określenie kierunków, w których podąża lub powinien podążać system finansowy w Polsce w warunkach postępującej globalizacji w XXI wieku. Zakres czasowy monografii obejmuje okres po rozpoczęciu transformacji gospodarczej w Polsce, tj. lata 1989–2018 (w niektórych rozdziałach zakres ten jest krótszy lub dłuższy ze względu na dostępność danych lub poruszane zagadnienie), a przedmiotem badania są system finansowy w Polsce oraz – dla celów porównawczych – systemy finansowe w innych wybranych krajach (głównie europejskich). W kolejnych rozdziałach omówione zostały zagadnienia teoretyczne, rezultaty badań (w tym przeprowadzonych przez autorów) oraz płynące z nich wnioski. Część pierwsza opracowania, Polityka monetarna w Polsce – od transformacji do globalizacji, obejmuje cztery rozdziały dotyczące prowadzenia polityki w warunkach niepewności, inflacji, strategii polityki monetarnej oraz problemów współczesnej polityki monetarnej. Wybrane zagadnienia pokazują bezpośrednio ewolucję polskiej bankowości centralnej, ze szczególnym uwzględnieniem zastosowanych rozwiązań operacyjno-instytucjonalnych. Klamrą scalającą i tematyką wiodącą tej części jest wdrażanie przez Narodowy Bank Polski (NBP) strategii bezpośredniego celu inflacyjnego (BCI). Część druga monografii, Rynek kapitałowy i stabilność polskiego systemu finansowego – perspektywa lokalna i globalna, stanowi, symetryczny w stosunku do poprzedniego, zbiór czterech rozdziałów na temat historii i roli polskiego rynku kapitałowego, innowacji w systemie finansowym oraz stabilności polskiego systemu finansowego. Zakończenie zawiera wnioski z rozważań o charakterze teoretycznym oraz empirycznym, przedstawionych w obu częściach pracy.

  • Różnica w subiektywnej ocenie jakości mowy pomiędzy nastolatkami dwujęzycznymi a jednojęzycznymi
    • Przemysław Falkowski-Gilski
    • Stefan Brachmański
    • Maurycy Kin
    • Andrzej Dobrucki
    2021

    Proces percepcji mowy omawiany jest w szerokim zakresie dziedzin i dyscyplin naukowych, od nauk humanistycznych, technicznych, aż po nauki medyczne. Wiele badań skupia się np. na ocenie różnicy w grupach bez i z wykształceniem muzycznym. Skoro stwierdzono, że zdolności muzyczne wpływają na percepcję poszczególnych atrybutów dźwięku, autorzy postanowili zbadać, czy zdolności językowe także mogą mieć wpływ na ocenę jakości sygnału mowy. W pracy przedstawiono różnicę w postrzeganiu sygnałów mowy pomiędzy młodzieżą szkolną z klas dwujęzycznych i jednojęzycznych. Badania obejmowały grupę 30 uczestników, po 15 osób w każdej klasie, w wieku 16-18 lat. Próbki mowy składały się z 3 zbiorów: angielski amerykański, angielski brytyjski i polski. Otrzymane wyniki mogą stanowić cenną wskazówkę zarówno dla naukowców jak i nauczycieli w szkolnictwie podstawowym, średnim oraz wyższym, a także inżynierów projektujących usługi i dostarczających treści.

  • Rubrene Thin Films with Viably Enhanced Charge Transport Fabricated by Cryo-Matrix-Assisted Laser Evaporation
    • Rafał Jendrzejewski
    • Natalia Majewska
    • Sayani Majumdar
    • Sawczak Mirosław
    • Jacek Ryl
    • Gerard Śliwiński
    2021 Full text Materials

    Among organic semiconductors, rubrene (RB; C42H28) is of rapidly growing interest for the development of organic and hybrid electronics due to exceptionally long spin diffusion length and carrier mobility up to 20 cm2V−1s−1 in single crystals. However, the fabrication of RB thin films resembling properties of the bulk remains challenging, mainly because of the RB molecule’s twisted conformation. This hinders the formation of orthorhombic crystals with strong π–π interactions that support the band transport. In this work, RB films with a high crystalline content were fabricated by matrix-assisted laser evaporation and the associated structure, composition, and transport properties are investigated. Enhanced charge transport is ascribed to the crystalline content of the film. Spherulitic structures are observed on top of an amorphous RB layer formed in the initial deposition stage. In spherulites, orthorhombic crystals dominate, as confirmed by X-ray diffraction and the absorption and Raman spectra. Surprisingly, nanowires several microns in length are also detected. The desorption/ionization mass and X-ray photoelectron spectra consistently show minimal material decomposition and absence of RB peroxides. The observed carrier mobility up to 0.13 cm2V−1s−1, is close to the technologically accepted level, making these rubrene films attractive for spintronic and optoelectronic applications

  • Rynek pracy w Azerbejdżanie, Armenii i Gruzji
    • Krystyna Gomółka
    2021

    Praca ukazuje zmiany na rynku pracy w trzech państwach Kaukazu Południowego w latach 2000-2020

  • RYNEK PRACY w dobie pandemii COVID-19 na przykładzie Azerbejdżanu i Polski
    • Krystyna Gomółka
    • Marzena Kacprzak
    • Dorota Kmieć
    • Agnieszka Król
    • Janusz Majewski
    2021

    Nieoczekiwane pojawienie się pandemii COVID-19 spowodowało prawdziwą rewolucję w wielu sektorach gospodarek na całym świecie. Jedne z nich dotknięte zostały bardziej niż inne, a z kolei niektóre, jak na przykład branża e-commerce, kurierska, EdTech – edukacja online, przeżywały wręcz prawdziwy rozkwit. W zasadzie można powiedzieć, że każde państwo odczuwa skutki pandemii, zwłaszcza te negatywne, choć oczywiście uwarunkowane jest to wieloma różnymi czynnikami. Kryzys nie ominął też rynków pracy na całym świecie. Panująca na nich sytuacja w dość dużym stopniu uzależniona jest od ich kondycji z czasów sprzed pandemii, a także efektywności mechanizmów, zwłaszcza w kontekście adaptacji i funkcjonowania w turbulentnym otoczeniu. Polityka rynku pracy w poszczególnych krajach stanęła przed trudnym zadaniem, jakim jest konieczność wdrażania rozwiązań, często innowacyjnych, które pomogą zapobiec wzrastającej stopie bezrobocia oraz zapewnić równowagę w obszarze popytu i podaży pracowników, uwzględniając kształtujący się nowy profil kompetencyjny pracowników na rynku pandemicznym, a także w niedalekiej przyszłości popandemicznej. Autorzy niniejszej monografii podjęli próbę identyfikacji kluczowych trendów i zjawisk na dotkniętych skutkami pandemii rynkach pracy, ze szczególnym uwzględnieniem sytuacji panującej w Azerbejdżanie i Polsce. Analizę rynku pracy oparto na wynikach własnych badań empirycznych. Cele szczegółowe pracy dotyczyły m.in. charakterystyki rynków pracy w Azerbejdżanie i Polsce; określenia sytuacji różnych grup społecznych (kobiet, pracowników 50+, młodych pracowników) na rynku pracy w okresie kryzysu; identyfikacji sytuacji na rynku pracy osób zatrudnionych w korporacjach i MSP w kontekście pandemii COVID-19.

  • 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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.