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Gdańsk University of Technology

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Publications from the year 2024

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  • Typology, current state and non-destructive testing of timber roof trusses of historic churches in the West Vistula Delta, Poland
    • Tomasz Zybała
    • Monika Zielińska
    • Magdalena Rucka
    • Jarosław Przewłócki
    • Karol Grębowski
    2024 Full text Heritage Science

    This paper presents the current state of conservation of historic roof churches located in the Żuławy of Gdańsk (Poland). It also describes the architecture of these temples, the region itself and old carpentry techniques for constructing roof trusses. Interdisciplinary tests were carried out in six churches. The geometry of the load bearing structures, the moisture content and the carpentry technique were specified. The field survey also included visual inspections and non-destructive testing of timber structural elements of the roof constructions. The ground penetrating radar and ultrasonic testing methods were used to assess the structure and extent of the damage to the timber elements. The interdisciplinary research presented in this article is important in the planning of historic buildings conservation works and it might be applied to other timber structures.

  • UAV measurements and AI-driven algorithms fusion for real estate good governance principles support
    • Paweł Tysiąc
    • Artur Janowski
    • Marek Walacik
    2024 International Journal of Applied Earth Observation and Geoinformation

    The paper introduces an original method for effective spatial data processing, particularly important for land administration and real estate governance. This approach integrates Unmanned Aerial Vehicle (UAV) data acquisition and processing with Artificial Intelligence (AI) and Geometric Transformation algorithms. The results reveal that: (1) while the separate applications of YOLO and Hough Transform algorithms achieve building detection rates up to 77% and 83%, respectively, (2) a novel methodology is proposed to combine spatial data and assess their quality of the detected buildings by comparing the generated building polygons with existing cadastral maps. The evaluation uses a polygon-based comparison approach, which computes metrics such as Precision, Recall, F1-Score, and Accuracy based on the spatial relationships between predicted and reference building contours, (3) the weighted model showed about 7 % improvement in accuracy compared to cadastral data. This innovative approach substantially improves spatial data processing, aiding in implementing principles for real estate good governance and offering a valuable asset for various land administration applications.

  • UE ETS: an in-depth descriptive analysis.
    • Helena Anacka
    • Claudia Nardone
    2024

    The European Emission Trading System (EU ETS) plays a pivotal role in the EU’s strategy to address climate change, serving as a fundamental instrument for cost-effective reduction of greenhouse gas emissions. Notably, it inaugurated the word’s first major carbon market and it continues to the largest one. Chapter 1 provides an in-depth examination of the EU ETS, spanning from its inception in 2005 to 2020. After providing a descriptive analysis of emission from stationary installation by year, country, and sector, market dynamics is analyzed. This analysis encompasses transaction frequency and volumes traded annually, as well as a breakdown by type of account and month. The study places special emphasis on Italian firms, comparing trading and non-trading entities, firms engaged solely in buying or purchasing, and those involved in both buying and purchasing activities. Additionally, the analysis distinguishes between inter-firm and intra-firm trades within the market.

  • Ulgi podatkowe w sektorze MŚP - wyniki badań
    • Piotr Kasprzak
    2024

    Niniejsza książka powstała na podstawie rozprawy doktorskiej autora, której podstawowe cele obejmowały zbadanie i określenie, czy i w jakim stopniu preferencje podatkowe w postaci ulg i zwolnień są wykorzystywane przez przedsiębiorców należących do sektora MŚP. Celem poznawczym niniejszej pracy jest uporządkowanie wiedzy na temat stymulacyjnej funkcji podatków realizowanej poprzez system ulg i zwolnień. Badanie składało się z czterech etapów – badania pilotażowego w postaci sondażu ankietowego i wywiadów uzupełniających, zasadniczego badania ankietowego oraz drugiej tury wywiadów. Metoda sondażu diagnostycznego została wykorzystana przy zbieraniu danych pierwotnych wśród przedsiębiorstw sektora MŚP. Instrumentem pomiaru był opracowany przez autora kwestionariusz ankiety. Celem było przebadanie przedsiębiorstw spełniających definicję UE w zakresie mikro-, małych i średnich podmiotów, posiadających siedzibę na terytorium RP, podatników podatku dochodowego (CIT lub PIT), z różnych branż i sektorów Analiza wyników przeprowadzonych badań pozwoliła dokonać oceny wykorzystania ulg i zwolnień przez mikro-, małe i średnie przedsiębiorstwa. Wyniki badań pokazują, że system obowiązujących w Polsce preferencji podatkowych nie jest idealny. Ponadto, ze względu na wielokierunkowy zakres oddziaływania instrumentów podatkowych, ocena poszczególnych wdrożonych do systemu podatkowego rozwiązań jest zagadnieniem wielce skomplikowanym, a jednoznaczna ocena skuteczności oddziaływania – niejednokrotnie niemożliwa.

  • Ultra-Compact Self-Quadruplexing Microfluidically Frequency Reconfigurable Slot Antenna Using Half-Mode SIW
    • Rusan Kumar Barik
    • Sławomir Kozieł
    2024 AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS

    In this brief, the design of an ultra-compact self-quadruplexing frequency reconfigurable antenna (SQFRA) utilizing a half-mode substrate-integrated waveguide (HMSIW) and microfluidic channels is discussed. Four HMSIW cavities fed by four microstrip lines and slots are used to construct a highly compact antenna. The microstrip feedings to the HMSIW cavities are applied in such a way that the proposed antenna exhibits self-quadruplexing properties with good isolation. The working principle is explained by employing surface current densities, and an equivalent circuit model. In order to achieve frequency tunability, two or three empty sockets associated with each HMSIW cavity are drilled from the bottom plane and filled with dielectric fluids. The effect of height and locations of fluidic channels are discussed in detail. To validate the proposed tunability, a prototype of SQFTA is fabricated and demonstrated. The fabricated antenna provides frequency ranges of 16.46%, 17.84%, 11.99%, and 14.94% at the first, second, third, and fourth frequency bands, respectively. The SQFTA exhibits a small footprint of 0.084λg2, which makes it the most compact self-quadruplexing tunable antenna in the open literature. Furthermore, the fabricated antenna features high isolation greater than 24.7dB, and realized gain greater than 3.55 dBi at all the operating frequencies.

  • Ultrafast high-temperature sintering (UHS) of cerium oxide-based compound
    • Ahsanul Kabir
    • Bartłomiej Lemieszek
    • Jakub Karczewski
    • Emanuele De Bona
    • Maxim Varenik
    • Sebastian Molin
    • Mattia Biesuz
    2024 Full text Open Ceramics

    Ultrafast high-temperature sintering (UHS) is an innovative sintering technique that can densify ceramics in a few seconds, dramatically reducing the carbon footprint and firing costs. In this work, the feasibility of applying UHS in Gd-doped ceria (GDC) and GDC-Er-stabilized bismuth oxide (ESB) composite powders was investigated. At high UHS currents (22-24 A), a fully dense GDC sample with a large grain size was obtained. Nonetheless, most of the GDC pellets exhibited micro/macro cracks, which were reduced by lowering the sample thickness. Moreover, the GDC-ESB composite sample exhibits no cracks or fragmentation at all, thanks to ESB as a sintering aid. This type of sample was further characterized from an electrochemical and electromechanical point of view. The GDC-ESB material displays an ionic conductivity value of ~1.5 x 10−2 S/cm at 600 °C and frequency-stable (0.1-350 Hz) room temperature electrostriction strain coefficient of ~10−18 (m/V)2.

  • Ultra-Wideband Vivaldi Antenna with an Integrated Noise-Rejecting Parasitic Notch Filter for Online Partial Discharge Detection
    • Sayed Mohammad Kameli
    • Shady S. Refaat
    • Haitham Abu-Rub
    • Ahmad Darwish
    • Ali Ghrayeb
    • Marek Olesz
    2024 IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT

    Power transformers and gas-insulated switchgear (GIS) play crucial roles in electrical power grids. However, they may suffer from degradation of insulation material due to wear and tear, leading to their imminent failure. Partial discharges (PDs) are an initial sign of insulation materials degradation which emit signals spanning various physical domains, including electromagnetic. PDs are temporally narrow, high-frequency, stochastic radiation sources. The Ultra-Wideband Vivaldi Antenna is the key element for the detection of PDs in power transformers and gas-insulated switchgear. However, they may be subject to different interference environments due to external sources of telecommunication radiation noise occupying the 2.4 GHz – 2.5 GHz band. Noise mixing with PD signals is challenging to resolve, especially for external sensors. Wi-Fi and Bluetooth signals from mobile devices easily overshadow faint PD signals. Band-reject frequency filters may be attached to the antenna, often at the detriment of the insertion loss. The integrated filter does not require any additional post-processing, making it less computationally demanding for smaller processors used in practice. Wi-Fi and Bluetooth degrade the PD signal, necessitating an integrated analog notch filter for noise removal. Therefore, an external ultra-wideband (UWB) Vivaldi antenna with an integrated noise-rejecting parasitic notch filter is designed, fabricated, and tested to detect PDs in electrical assets such as transformers, power cables, and GIS, with GIS being the focus in the experimental validation in this study. A comparative study of the proposed antenna is presented. This paper proposed an antenna that is designed to provide coverage of 95.516% of the 0.226 GHz – 3.506 GHz frequency band, with an average return loss of -16.04 dB and a peak gain of 5.5 in the working band, excluding the notched band. The peak return loss in the 2.4 GHz – 2.5 GHz rejection band is -2.68 dB, with an average attenuation of -35.74 dB. This wide coverage is demonstrated in this paper using simulation and experimentally.

  • Understanding the Dominant Physics Mechanisms on the p-i-n Perovskite Solar Cells Fabricated by Scalable Slot-Die Coating Process in Ambient Air
    • Damian Głowienka
    • Shih-Han Huang
    • Pei-Huan Lee
    • Feng-Yu Tsai
    • Wei-Fang Su
    2024 Full text Solar RRL

    Perovskite solar cells (PSC) are emerging technologies that have shown continuous improvement in power conversion efficiency (PCE) and stability. However, a very important aspect that has been seldom considered is the reproducibility of PCE of PSC devices. It is possible to achieve PCE from 10.21% to 17.05% using scalable slot-die-coating technique. However, a spatial distribution of performance is clearly observed for device samples on a 4 × 4 cm substrate. The relatively low PCE is mainly coming from the losses of electrical mechanism. To have in-depth understanding of the losses, the dominant loss analysis techniques including numerical simulations are used to explore the mechanism. In the results, it is indicated that a part of efficiency decrease is due to the increase of bulk defect density which linearly changes with the quality of the perovskite layer and related to recombination process. However, extremely high-charge-carrier transportation losses are found at the HTL/perovskite interface that are related to the Fermi-level pinning mechanism for low-efficiency device. The result of physics insight of perovskite solar cells leads to a strategy, where chemical passivation technique is used to achieve the PCE from 13.81% to 18.07% for the batch of devices with good reproducibility.

  • Understanding the Ukrainian Migrants Challenges in the EU: A Topic Modeling Approach
    • Nina Khairova
    • Nina Rizun
    • Charalampos Harris Alexopoulos
    • Magdalena Ciesielska
    • Arsenii Lukashevskyi
    • Ivan Redozub
    2024 Full text

    Confronted with the aggression against Ukraine in 2022, Europe faces one of the most important humanitarian challenges - the migration of war refugees from Ukraine, most of them women with children and the elderly. Both international institutions such as the European Union and the United Nations, but also national governments and, above all, local governments, which are the main providers of services and resources for refugees, are taking a number of measures to meet the needs. The extraordinary nature and extensive humanitarian needs pose exceptional challenges for both governments and Non-Governmental Organizations (NGOs) as well as civil society. The European countries adopted distinct reception procedures to accommodate war refugees in their territories. The purpose of this paper is to examine the challenges of war refugees from Ukraine and gain an understanding of how they vary across selected European countries. Using a text analytics approach such as BERTopic topic modeling, we analyzed text messages published on Telegram channels from February 2022 to September 2023, revealing 12 challenges facing Ukrainian migrants. Furthermore, our study delves into these challenges distribution across 6 major European countries with significant migrant populations, providing insights into regional differences. Additionally, temporal changes in 8 narrative themes in discussions of Ukrainian migration, extracted from official government websites, were examined. Together, this research contributes (1) to demonstrating how analytics-driven methodology can potentially be used to extract in-depth knowledge from textual data freely available on social media; and (2) to a deeper understanding of the various issues affecting the adaptation of Ukrainian migrants in European countries. The study also provides recommendations to improve programs and policies to better support the successful integration of Ukrainian migrants in host countries

  • Underwater Electrochemical Offshore Tests of a Paint Coating Applied in Water on the Legs of an Oil Production Platform
    • Juliusz Orlikowski
    • Krzysztof Żakowski
    • Michał Szociński
    • Piotr Igliński
    • Agata Jazdzewska
    • Łukasz Gaweł
    2024 Materials

    This paper presents the methodology developed for underwater measurements using electrochemical impedance spectroscopy (EIS) technique, aimed at determining the resistance of an epoxy coating applied in seawater to the legs of an oil production platform. Performing such underwater tests in an offshore environment was technically challenging. The results of measurements obtained on the platform were confronted with comparative results obtained in the laboratory, where the properties of the coating applied in water collected from the Baltic Sea (thickness, hardness, adhesion, and electrical resistance) were examined. This made it possible to conclude about the correctness of the paint coating application by divers on the legs of the platform. The single-layer epoxy coating applied by brush to the platform legs had a resistance above 10 kΩ·cm2 and thus met the assumed minimum resistance of the protective coating cooperating with cathodic protection as the anti-corrosion protection system of the platform legs. The synergy of these two technologies ensures full protection of offshore structures against corrosion. Measurements of the potential of the platform legs confirmed this. Before painting, the potential value at a depth of 0–15 m was 310 ÷ 320 mV versus the zinc reference electrode, while after painting the potential value decreased to 220 ÷ 240 mV, which means that the effect of full cathodic protection was achieved and the platform legs were protected from corrosion. The developed methodology for underwater EIS measurements on the high seas can be applied to any underwater metal structure to assess the quality of protective coatings.

  • Unequally-Spaced Slot Strategy for Radiation Null Reduction in Single SIW-Embedded Antenna Element
    • Meha Agrawal
    • Ravi Yadav
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2024 Full text Scientific Reports

    The incorporation of higher-order modes (HOMs) can substantially augment the antenna gain and bandwidth, but this improvement is typically accompanied by compromised radiation performance including radiation nulls and higher side lobe levels. In this study, an inventive strategy is introduced to reduce the radiation nulls and the side lobe levels of a single antenna element by positioning multiple slots of the radiating element at unequal spacing. Dual hybrid HOMs are analyzed inside a Substrate Integrated Waveguide (SIW)-based cavity to design a wide band, enhanced gain dual-polarized antenna. The radiating element of the antenna is designed with multiple slots positioned at unequal spacing but symmetrical along the origin. This methodology provides three-fold advantages: a reduction of side lobes, an adjustment of phase center, and a significant reduction of radiation nulls. The antenna has been fabricated, and experimentally validated. The antenna exhibits a reduction in radiation null to –0.5 dB, a phase adjustment of the main lobe to 0°, and a reduction in side lobe level from -14.4 dB (N = 2, equal spacing) and –15.5 dB (N = 4, equal spacing) a maximum of -19.7 dB (N = 4, unequal spacing) at 12.35 GHz in the phi-0 plane. Excellent agreement between measured and simulated results corroborates the efficacy of the proposed approach. The significant improvement in the radiation performance of the single-element antenna design sets the antenna design apart from the state-of-the-art solutions.

  • Uniwersalne uchwyty obróbkowe wykorzystujące siły magnetyczne
    • Adam Barylski
    2024 Projektowanie i Konstrukcje Inżynierskie

    Przedstawiono współczesne konstrukcje uniwersalnych uchwytów przedmiotowych wykorzystujące do zamocowania przedmiotów obrabianych siły magnetyczne. Analizowano uchwyty magnetyczne i elektromagnetyczne w technologia obróbki wiórowej i ściernej oraz w technikach spawalniczych.

  • Unlocking the electrochemical performance of glassy carbon electrodes by surface engineered, sustainable chitosan membranes
    • Agata Smułka
    • Mateusz Cieślik
    • Adrian Olejnik
    • Artur Zieliński
    • Jacek Ryl
    • Tadeusz Ossowski
    2024 Full text BIOELECTROCHEMISTRY

    Chitosan coatings, derived from crustacean shell waste, possess inherent biocompatibility and biodegradability, rendering them suitable for various biomedical and environmental applications, including electrochemical biosensing. Its amine and hydroxyl functional groups offer abundant sites for chemical modifications to boost the charge transfer kinetics and provide excellent adhesion, enabling the construction of robust electrode-coating interfaces for electroanalysis. This study explores the role of electrostatically-driven chemical interactions and crosslinking density originating from different chitosan (Cs) and glutaraldehyde (Ga) concentrations in this aspect. Studying anionic ([Fe(CN)6]3−/4−), neutral (FcDM0/+), and cationic ([Ru(NH3)6]2+/3+) redox probes highlights the influence of Coulombic interactions with chitosan chains containing positively-charged pathways, calculated by DFT analysis. Our study reveals how a proper Ch-to-Ga ratio has a superior influence on the cross-linking efficacy and resultant charge transfer kinetics, which is primarily boosted by up to 20× analyte preconcentration increase, due to electrostatically-driven migration of negatively charged ferrocyanide ions toward positively charged chitosan hydrogel. Notably the surface engineering approach allows for a two-orders of magnitude enhancement in [Fe(CN)6]4− limit of detection, from 0.1 µM for bare GCE down to even 0.2 nM upon an adequate hydrogel modification.

  • Unraveling Energy Transfer and Fluorescence Quenching Dynamics in Biomolecular Complexes: A Comprehensive Study of Imiquimod-Rifampicin Interaction.
    • Sudhanshu Sharma
    • Dineshbabu Takkella
    • Abhinav Srivastava
    • Jacek Czub
    • Subrahmanyam Sappati
    • Krishna Gavvala
    2024 PHYSICAL CHEMISTRY CHEMICAL PHYSICS

    In nature, numerous biomolecules are implicated in charge transfer (CT) and energy transfer (ET) mechanisms crucial for fundamental processes such as photosynthesis. Unveiling these mechanisms is pertinent to multiple disciplines including chemistry, engineering and biochemistry. This letter presents a study involving two molecules forming a model system with efficient ET properties. Specifically, their complex exhibits dark quenching phenomena arising from fluorescence resonance energy transfer (FRET) from the donor (imiquimod) to the acceptor (rifampicin). Supplemented by experimental findings, molecular dynamics simulations and time dependent density functional theory (TD-DFT) calculations conclusively validate the ET properties from the donor to the acceptor as described above

  • Unraveling the role of boron dimers in the electrical anisotropy and superconductivity in boron-doped diamond
    • Michał Sobaszek
    • Soonho Kwon
    • Tomasz Klimczuk
    • Paweł P. Michałowski
    • Jacek Ryl
    • Bogdan Rutkowski
    • Dongying Wang
    • Xinwei Li
    • Marc Bockrath
    • Robert Bogdanowicz
    • William A. Goddard III
    2024 CARBON

    We use quantum mechanics (QM) to determine the states formed by B dopants in diamond. We find that isolated B sites prefer to form BB dimers and that the dimers pair up to form tetramers (BBCBB) that prefer to aggregate parallel to the (111) surface in the <110> direction, one double layer below the H-terminated surface double layer. These tetramers lead to metallic character (Mott metal Insulator Transition) with holes in the valence band near the point and electrons in the BBCBB tetramer promoted band along the X direction. Our experiments find very significant anisotropy in the superconductivity for boron-doped diamond thin films prepared with Microwave Plasma Assisted Chemical Vapor Deposition using deuterium-rich plasma. This leads to much higher conductivity in the X direction than the Y direction, as predicted by the QM. This phase transition to the anomalous phase is linked with the emergence of boson quantum entanglement states behaving as a bosonic insulating state. These anisotropic superconducting properties of the diamond film might enable applications such as single-photon detectors. We expect that this formation of a dirty superconductivity state is related to the BBCBB tetramers found in our QM calculations.

  • Unsupervised Learning for Biomechanical Data Using Self-organising Maps, an Approach for Temporomandibular Joint Analysis
    • Mateusz Troka
    • Wiktoria Wojnicz
    • Katarzyna Szepietowska
    • Izabela Lubowiecka
    2024

    We proposed to apply a specific machine learning technique called Self-Organising Maps (SOM) to identify similarities in the performance of muscles around human temporomandibular joint (TMJ). The performance was assessed by measuring muscle activation with the use of surface electromyography (sEMG). SOM algorithm used in the study was able to find clusters of data in sEMG test results. The SOM analysis was based on processed sEMG data collected when testing subjects performing four mandibular motions: opening, closing, protrusion and retrusion. Muscle activation of four TMJ muscles (masseter right, masseter left, temporalis right and temporalis left) were used as input variables for SOM algorithm. The results of the network are presented on U-matrix maps. These maps consist of formed groupings that correspond to similarities in data points that clustered together. The clustering implies similarity in muscle activation of different subjects. The results show that it is possible to cluster medical datasets with SOM algorithm in the analysis of full jaw motions, which may support the diagnostic process.

  • Unusual dynamics and nonlinear thermal self-focusing of initially focused magnetoacoustic beams in a plasma
    • Anna Perelomova
    2024 Full text CONTRIBUTIONS TO PLASMA PHYSICS

    Unusual thermal self-focusing of two-dimensional beams in plasma which axis is parallel to the equilibrium straight magnetic field is considered. The equi- librium parameters of plasma determine scenario of a beam divergence (usual or unusual) which is stronger as compared with a flow without magnetic field. Nonlinear thermal self-action of a magnetosonic beam behaves differently in the ordinary and unusual cases. Damping of wave perturbations and normal defocusing in gases leads to reduction of the magnitude of initially planar per- turbations at the axis of a beam. Additional thermal self-focusing nonspecific for gases occurs in plasma under some condition which counteracts this reduc- tion. The theory and numerical examples concern thermal self-action of initially focused (defocused) magnetosonic beam. Dynamics of perturbations in a beam is determined by dimensionless parameters responsible for diffraction, damp- ing of the wave perturbations, initial radius of a beam’s front curvature, and the ratio of viscous to thermal damping coefficients.

  • Unveiling the electron-induced ionization cross sections and fragmentation mechanisms of 3,4-dihydro-2H-pyran
    • Tomasz Wąsowicz
    • Michał Jurkowski
    • Allison Harris
    • Ivan Ljubić
    2024 Full text JOURNAL OF CHEMICAL PHYSICS

    The interactions of electrons with molecular systems under various conditions are essential to interdisciplinary research fields extending over the fundamental and applied sciences. In particular, investigating electron-induced ionization and dissociation of molecules may shed light on the radiation damage to living cells, the physicochemical processes in interstellar environments, and reaction mechanisms occurring in combustion or plasma. We have, therefore, studied electron-induced ionization and dissociation of the gas phase 3,4-dihydro-2H-pyran (DHP), a cyclic ether appearing to be a viable moiety for developing efficient clinical pharmacokinetics and revealing the mechanisms of biofuel combustion. The mass spectra in the m/z = 10–90 mass range were measured at several different energies of the ionizing electron beam using mass spectrometry. The mass spectra of DHP at the same energies were simulated using on-the-fly semi-classical molecular dynamics (MD) within the framework of the QCxMS formalism. The MD settings were suitably adjusted until a good agreement with the experimental mass spectra intensities was achieved, thus enabling a reliable assignment of cations and unraveling the plausible fragmentation channels. Based on the measurement of the absolute total ionization cross section of DHP (18.1 ± 0.9) × 10−16 cm2 at 100 eV energy, the absolute total and partial ionization cross sections of DHP were determined in the 5–140 eV electron energy. Moreover, a machine learning algorithm that was trained with measured cross sections from 25 different molecules was used to predict the total ionization cross section for DHP. Comparison of the machine learning simulation with the measured data showed acceptable agreement, similar to that achieved in past predictions of the algorithm.

  • Upward convergence patterns in chosen environmental-related SDGs
    • Marta Kuc-Czarnecka
    • Iwona Markowicz
    • Agnieszka Sompolska-Rzechuła
    2024 Full text ECOLOGICAL INDICATORS

    Sustainable development is a challenge facing humanity. EU countries not only strive to reach their specific objectives, but they also work collaboratively towards shared goals. There is a need to balance synergies and compromises to address these objectives effectively. When discussing countries' development and people's well-being, one often focuses on socio-economic development. However, it is crucial not to overlook the environmental repercussions and the need to care for the planet. Thus, our article pays attention to the sustainable development objectives of the “planets” group. We analysed upward convergence in the scope of the “Planet” goals, i.e. the analysis of improving the results of Member States and, at the same time, reducing the differences between them. Convergence trends were examined individually for each variable and then for all variables combined (Planet). Our article fills a research gap because, to our knowledge, analyses of the trajectories of achieving individual goals in such a context have not been analysed so far. The results of our study indicate a favourable situation in the case of six out of eight examined variables. Areas in which intensification of activities is necessary for some EU countries are an increase in energy productivity and a reduction in net greenhouse gas emissions of land use. The second stage of the study concerned the development paths of individual countries. The most challenging situation concerns the variable sdg_07_20 (final energy consumption in households per capita). In this case, as many as 12 countries belong to the weak group.

  • Usability of Mobile Applications: A Consolidated Model
    • Paweł Weichbroth
    2024 Full text IEEE Access

    Mobile devices have become an integral part of the digital ecosystem, connecting people, businesses, and information around the world in ways never before possible. In particular, smartphones, tablets and other handheld devices equipped with mobile applications have changed every aspect of our lives. Today, a user can choose from nearly five million applications available for both Android and iOS operating systems. However, only 0.5 percent of applications succeed in the marketplace. Many factors contribute to their failure, including poor design, lack of value, privacy violations, and usability issues. While usability is often identified as a major concern, there seems to be no agreement between researchers and practitioners on its nature, although many models have been developed. This paper attempts to find a consensus by synthesizing the state of the art literature. More specifically, we aim to develop a consolidated, universal usability model for mobile applications, through the lens of existing human computer interaction theory. In order to achieve this goal, our study uses a mix of qualitative and quantitative methods. Overall, the research methodology consisted of two steps. First, we conducted a systematic literature review to identify, collect, and analyze current research on mobile usability. Second, we used the meta-analysis approach to quantitatively describe the extracted data and summarize the findings. The PACMAD+3 model was developed and discussed in light of the results obtained and the PACMAD model. While our model borrows seven attributes from its ancestor, the remaining three attributes were derived from the synthesis of other studies, along with three external factors adopted from the ISO 9241-11 standard. In addition, we reviewed existing definitions of usability attributes. We expect that this unified approach will lead to a better understanding of mobile usability, including all relevant attributes and factors, thus making a significant contribution to theory. On the other hand, in practice, the PACMAD+3 model can be used to translate abstract attributes into tangible terms, which is particularly useful in empirical research focused on measuring and evaluating the usability of mobile applications.