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Gdańsk University of Technology

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  • A palatal prosthesis from archaeological research in the St Francis of Assisi church in Cracow (Poland)
    • Anna E. Spinek
    • Marta Kurek
    • Krzysztof Demidziuk
    • Marcin Nowak
    • Magdalena Śliwka-Kaszyńska
    • Anna Drążkowska
    2024 Journal of Archaeological Science-Reports

    The hard palate is a septum that not only prevents food from entering between the oral and nasal cavity, but also plays an important role during breathing or speech. The presence of cavities within it negatively affects the comfort of life of people with this type of impairment. Hence, in the literature one can find examples of the use of hard palate prostheses to restore the separation between the nasal and oral cavity. During archaeological research conducted in 2017–18 in the church of St Francis of Assisi in Cracow, the remains of a man with a cleft palate, who died at the age of about 50, were found. His burial is dated to the eighteenth century. Within his mouth, the presence of a palatal prosthesis was noted. This is the first case in Poland of finding an individual with an obturator tailored to its needs. The aim of the work is to present the structure and elemental composition of the found prosthesis and comparisons to the other obturators known from written sources. Macroscopic analysis showed the presence of an elliptical-shaped metal diaphragm and a textile “tampon” entering nasal cavity. The metal part of the prosthesis was made of copper alloy, covered with a layer of silver and gold. The comparison of the analysed obturator with examples from the literature indicates its great similarity to those used in the sixteenth and eighteenth centuries.

  • A Planar-Structured Circularly Polarized Single-Layer MIMO Antenna for Wideband Millimetre-Wave Applications
    • Ubaid Ullah
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Shahanawaz Kamal
    2024 Full text Engineering Science and Technology-An International Journal-JESTECH

    In this paper, a simple geometry, planar-structured printed multiple-input-multiple-output (MIMO) antenna utilizing dual circular polarization (CP) is presented. The proposed numerically and experimentally validated design features a fully grounded coplanar waveguide (CPW) and a systematically perturbed feedline radiator. The fringing electric (E) field along the feedline is altered by extruding periodic stubs on each side of the microstrip line extended from a grounded CPW. The different physical size of the stubs on each side, plus a slight offset introduced between the stubs breaks the symmetry of the vector E-fields on both side of the edges. The asymmetric E-field weakens the intensity of the respective magnetic current on the opposite side for a wider spectrum, resulting in a wideband operation. The asymmetric vertical magnetic current along the length of the stubs and the combined current on the horizontal edges yield 90-degree out-of-phase orthogonal field components, radiating circularly polarized waves. The proposed design has the advantage of topological simplicity and ease of polarization sense alteration. Owing to this, the design is implemented in MIMO configuration with each port radiating a different sense of CP. The antenna's simulated and measured -10 dB impedance bandwidth is more than 26.5% ranging from 24.6 GHz to 32.1 GHz frequency. Additionally, the antenna retains an axial ratio (AR) of 3 dB or less from 26 GHz to 31.8 GHz. The peak realized gain (RG) of the antenna is 10.3 dBic with an average value of ~ 9.5 dBic across the bandwidth confirming stable radiation in the broadside direction. At the same time, the envelop correlation coefficient and the diversity gain are about 0.01 and 10 dB, respectively over the operating band.

  • A Probabilistic Optimisation Approach to the Equitable Controller Location Problem
    • Erison Ballasheni
    • Dritan Nace
    • Artur Tomaszewski
    • Alban Zyle
    2024 IEEE Transactions on Network and Service Management

    The ability of the Software-Defined Network (SDN) to transport traffic flows depends, in particular, on the SDN switches being able to communicate with SDN controllers, which are responsible for the setup of network connections and the configuration of switches. Since in principle the number of SDN controllers is limited they must be installed in a set of carefully selected node locations. Whereas the problem of controller placement is well defined and has been thoroughly studied and effectively solved for the nominal network state, it becomes difficult when the network is subject to attacks, especially as they can occur anywhere and anytime. In this paper we tackle the problem of controller placement resilient to network attacks considering probabilistic characterisation of attacks and equitable access of switches to controllers. We treat the problem as a specific facility location problem with the objective of providing resilience to network attacks, and analyze a couple of major solution fairness criteria. We derive a number of Mixed-Integer Linear Programming (MILP) problem models that exploit robust optimization and fair optimization concepts and techniques, and examine their effectiveness by means of a numerical study that uses five transport networks.

  • A probabilistic-driven framework for enhanced corrosion estimation of ship structural components
    • Krzysztof Wołoszyk
    • Yordan Garbatov
    2024 Full text RELIABILITY ENGINEERING & SYSTEM SAFETY

    The work proposes a probabilistic-driven framework for enhanced corrosion estimation of ship structural components using Bayesian inference and limited measurement data. The new approach for modelling measurement uncertainty is proposed based on the results of previous corrosion tests that incorporate the non-uniform character of the corroded surface of structural components. The proposed framework's basic features are outlined, and the detailed algorithm is presented. Further, the proposed framework is validated by comparison with the classical statistical approach and mass measurements, considering previous experimental work results. Notably, the impact of the number of measuring points is investigated, and the accuracy index is proposed to identify the optimum number of measurements. The developed framework has a significant advantage over the classical approach since measuring uncertainty is incorporated. Additionally, the confidence intervals of both mean value corrosion depth and standard deviation could be gathered due to the probabilistic character of the framework. Thus, the presented approach can potentially be used in the structural health monitoring of ship structural components and reliability analysis.

  • A procedure for the identification of effective mechanical parameters of additively manufactured elements using integrated ultrasonic bulk and guided waves
    • Erwin Wojtczak
    • Magdalena Rucka
    • Angela Andrzejewska
    2024 Full text MEASUREMENT

    The subject of the current work was a simple but robust novel two-stage procedure for the non-destructive determination of effective elastic constants using ultrasonic wave propagation. First, ultrasonic bulk wave velocities measured on cubic samples were used to calculate most of the elements of the stiffness matrix. Secondly, the remaining elements were determined using the dispersion curves of elastic guided waves measured on plate samples. Based on the complete stiffness matrix it was possible to calculate the complete set of effective elastic constants. The algorithm was verified for AM elements produced from PLA filament satisfying the conditions of transversely isotropic and orthotropic material models. For the transversely isotropic samples, Young’s moduli (E) varied from 2.6 to 2.9 GPa, shear moduli (G) equalled between 0.9 and 1.2 GPa, whereas Poisson’s ratios (ν) ranged between 0.20 and 0.32. In orthotropic sample the corresponding values were: E = 1.3–2.8 GPa, G = 0.6–1.2 GPa, and ν = 0.07–0.59. The results of the current study have been compared with references from the literature, giving satisfactory agreement.

  • A procedure for the visualization of fingerprint traces on standard and thermal paper using the electron excitation energy of 1,8-diazafluoren-9- one aggregates in a polyvinylpyrrolidone polymer
    • Aneta Lewkowicz
    • Martyna Czarnomska
    • Emilia Gruszczyńska
    • Katarzyna Karpienko
    • Maciej Wróbel
    • Michalina Chabowska
    • Piotr Bojarski
    2024 Full text Z Zagadnień Nauk Sądowych

    The scope of this study is a new procedure for visualizing dactyloscopic traces on an absorbent surface using a solution based on aggregates of 1,8-diazafluoren-9-one (DFO) in a polyvinylpyrrolidone polymer (PVP). An absorbent surface is defined as a plain or thermal paper, which is considered to be a difficult surface due to its varying chemical composition. In the case of the thermal paper surface, the procedure can be further improved by the addition of Au/Ag nanoparticles, which cause an enhancement of the fluorescence phenomenon from the surface of the fingerprint. The procedure requires the use of forensic illuminators and filters to reveal traces at the crime scene. Regarding the visualization of fingerprint prints in the forensic laboratory, the use of a stereo fluorescence microscope provides higher-resolution images when analyzing single patterns in the form of minutiae. The presented procedure is competitive with known, highly toxic current methods for revealing dactyloscopic traces using the DFO molecule. It also represents a key contribution to the development of methods for visualizing traces on thermal paper using fluorescent dyes and suitable control of their spectroscopic properties.

  • A prototype information system for managing and pricing e-waste
    • Krystian Jandy
    • Paweł Weichbroth
    2024 Full text

    There is no doubt that innovation drives development in all areas of human activity, including electrical and electronic equipment. However, the production of new equipment has a significant impact on the natural environment and a relatively high consumption of natural resources. To address these issues, the circular economy has been implemented in recent years by promoting and introducing numerous measures to facilitate the recycling of used goods. However, it has been found that there are many obstacles and difficulties currently faced by decision and policy makers. In this paper, we try to fill the research gap by presenting the prototype of an information system (IS) that could help not only these stakeholders, but also other interested parties, to move towards a circular economy through the efficient management of used electrical and electronic equipment (e-waste). In this context, we present the prototype of the system and elaborate on its two main components, namely functionality and user interface. Furthermore, we discuss the future research directions regarding the development of existing and new system features, followed by a comprehensive usability testing.

  • A Residential Building Extension Prototype to face Post-Pandemic Needs: Foreseen Challenges and Impacts
    • Anna Stefańska
    • Carlos C. Duarte
    • Katarzyna Zielonko-Jung
    • Nuno D. Cortiços
    • Daniel Mateus
    2024 Green Energy & Environment

    The COVID-19 pandemic highlighted the importance of outdoor spaces for maintaining physical and mental well-being. However, many urban residents lack private outdoor areas, which led to harmful health consequences during lockdowns. The research project aims to address and solve this issue by developing a physical/digital prototype called “X-TEND” that extends living space outdoors by attaching it to existing multi-story residential building facades. This prototype intends to promote healthier lifestyles, improving the well-being of individuals and positively impacts the urban surroundings aesthetics. X-TEND prototype uses a light, modular, and prefabricated approach for cost-effectiveness and environmental sustainability. It incorporates generative processes for structural and bioclimatic optimisation complemented by green building strategies to reduce environmental impact while maximising thermal and energy performance. Ultimately, X-TEND prototype contributes to a more sustainable built environment, fostering healthier and more liveable cities for current and future generations.

  • A review of explainable fashion compatibility modeling methods
    • Karolina Selwon
    • Julian Szymański
    2024 ACM COMPUTING SURVEYS

    The paper reviews methods used in the fashion compatibility recommendation domain. We select methods based on reproducibility, explainability, and novelty aspects and then organize them chronologically and thematically. We presented general characteristics of publicly available datasets that are related to the fashion compatibility recommendation task. Finally, we analyzed the representation bias of datasets, fashion-based algorithms’ sustainability, and explainable model assessment. The paper describes practical problem explanations, methodologies, and published datasets that may serve as an inspiration for further research. The proposed structure of the survey organizes knowledge in the fashion recommendation domain and will be beneficial for those who want to learn the topic from scratch, expand their knowledge, or find a new field for research. Furthermore, the information included in this paper could contribute to developing an effective and ethical fashion-based recommendation system.

  • A Review of Recent Advances in Human-Motion Energy Harvesting Nanogenerators, Self-Powering Smart Sensors and Self-Charging Electronics
    • Justyna Gołąbek
    • Michał Strankowski
    2024 Full text SENSORS

    In recent years, portable and wearable personal electronic devices have rapidly developed with increasing mass production and rising energy consumption, creating an energy crisis. Using batteries and supercapacitors with limited lifespans and environmental hazards drives the need to find new, environmentally friendly, and renewable sources. One idea is to harness the energy of human motion and convert it into electrical energy using energy harvesting devices—piezoelectric nanogenerators (PENGs), triboelectric nanogenerators (TENGs) and hybrids. They are characterized by a wide variety of features, such as lightness, flexibility, low cost, richness of materials, and many more. These devices offer the opportunity to use new technologies such as IoT, AI or HMI and create smart self-powered sensors, actuators, and self-powered implantable/wearable devices. This review focuses on recent examples of PENGs, TENGs and hybrid devices for wearable and implantable self-powered systems. The basic mechanisms of operation, micro/nano-scale material selection and manufacturing processes of selected examples are discussed. Current challenges and the outlook for the future of the nanogenerators are also discussed.

  • A review on analytical models of brushless permanent magnet machines
    • Ahmed Abbas
    • Atif Iqbal
    • Arkadiusz Lewicki
    • Reddy B. Prathap
    • M Mnzool
    2024 Full text INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS

    This study provides an in-depth investigation of the use of analytical and numerical methods in analyzing electrical machines. Although numerical models such as the finite-element method (FEM) can handle complex geometries and saturation effects, they have significant computational burdens, are time-consuming, and are inflexible when it comes to changing machine geometries or input values. Analytical models based on magnetic equivalent circuits (MEC) or solving Maxwell's equations can be faster and more flexible, but less accurate for complex machine structures. The paper focuses on the recent development of analytical models for brushless permanent-magnet (PM) machines that have become increasingly popular in low and medium- power applications. The literature review covers the recent developments in analytical models for PM machines with respect to various machine quantities such as magnetic flux density components, induced voltage, inductances, electromagnetic force/torque, efficiency, or unbalanced magnetic force (UMF). It outlines the advantages and disadvantages of different analytical models such as the zero-dimensional (0-D), one-dimensional (1-D), two-dimensional (2-D), and three-dimensional (3-D) analytical methods, as well as the Maxwell and basic mathematical analysis. Although the MEC models are faster than the numerical model, they are not as accurate for various structures of electrical machines including a great magnetic air gap. They also note that the analytical models based on the Maxwell equations are faster than the numerical ones and have the potential to obtain acceptable accuracy similar to the numerical models in electrical machines. Overall, this literature review provides valuable insights for researchers and engineers in selecting appropriate analytical models for PM machines. It highlights the trade-offs between accuracy and computational efficiency when choosing between numerical and analytical models, and the flexibility of analytical models to address changes in machine geometries or input values. Additionally, this helps researchers save time in determining appropriate references regarding the analytical models of brushless PM machines.

  • A review on carbon storage via mineral carbonation: Bibliometric analysis, research advances, challenge, and perspectives
    • Xiaodan Lin
    • Xingyang Li
    • Hongwen Liu
    • Grzegorz Boczkaj
    • Yijun Cao
    • Chongqing Wang
    2024 SEPARATION AND PURIFICATION TECHNOLOGY

    Mineral carbonation as a way of carbon storage has received a particular attention in the reduction of carbon dioxide (CO2) emission . This work gives a comprehensive description of the research trends and hotspots in the field of mineral carbonation for carbon storage based on bibliometric analysis. A total of 1507 articles were collected from the Web of Science database from 2010 to 2022 and analyzed in details, using a Citepace and VOSviewer software. Keyword cluster analysis indicates that research on mineral carbonation mainly involves natural minerals, industrial wastes, and cement-based materials. Research advances on carbon storage via mineral carbonation are summarized from the aspects of magnesium-based feedstocks and calcium-based feedstocks. Direct aqueous carbonation and indirect carbonation are the most promising methods. Mining tailings and industrial wastes are promising feedstocks for mineral carbonation. The slow kinetics and low carbonation capacity of feedstocks are the main obstacles for industrial application. Finally, challenges and prospects in mineral carbonation are put forward, which is conducive to its rapid and balanced development. This work provides the basis for the future development of cheap, efficient, and green large-scale mineral carbonation processes for carbon storage.

  • A review on fungal-based biopesticides and biofertilizers production
    • Dante Ferreyra-Suarez
    • Octavio García-Depraect
    • Roberto Castro Munoz
    2024 ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

    The escalating use of inorganic fertilizers and pesticides to boost crop production has led to the depletion of natural resources, contamination of water sources, and environmental crises. In response, the scientific community is exploring eco-friendly alternatives, such as fungal-based biofertilizers and biopesticides, which have proven effectiveness in enhancing plant health and growth while sustainably managing plant diseases and pests. This review article examines the production methodologies of these bioproducts, highlighting their role in sustainable agriculture and advancing our understanding of soil microorganisms. Despite their increasing demand, their global market presence remains limited compared to traditional chemical counterparts. The article addresses: 1) the production of biofertilizers and biopesticides, 2) their contribution to crop productivity, 3) their environmental impact and regulations, and 4) current production technologies. This comprehensive approach aims to promote the transition towards more sustainable agricultural practices.

  • A review on homogeneous and heterogeneous catalytic microalgal lipid extraction and transesterification for biofuel production
    • Vinoth Kumar Ponnumsamy
    • Hussein Al-Hazmi
    • Sutha Shobana
    • Jeyaprakash Dharmaraja
    • Dipak Ashok Jadhav
    • Rajesh Banu J
    • Grzegorz Piechota
    • Bartłomiej Igliński
    • Vinod Kumar
    • Amit Bhatnagar
    • Kyu-Jung Chae
    • Gopalakrishnan Kumar
    2024 Full text CHINESE JOURNAL OF CATALYSIS

    Extracting lipids from microalgal biomass presents significant potential as a cost-effective approach for clean energy generation. This can be achieved through the chemical conversion of lipids to produce fatty acid methyl esters via transesterification. The extraction mainly involves free fatty acids, phospholipids, and triglycerides, and requires less energy, making it an attractive option for satisfying the growing demand for fossil-derived energies. Several approaches have been explored for sustainable bioenergy production from microalgal species via catalytic, non-catalytic, and enzymatic transesterification. This review discusses recent insights into microalgal lipid extraction via solvent, Soxhlet, Bligh and Dyer’s, supercritical CO2, and ionic liquids solvent methods and lipid conversion by transesterification and homo/heterogeneous acid/base catalyzed, enzymatic, non-catalytic, and mechanically/chemically catalyzed in-situ techniques towards algal bioenergy production. Technical advances in both extraction and conversion are necessary for the commercialization of renewable energy sources.

  • A Review on Machine Learning Deployment Patterns and Key Features in the Prediction of Preeclampsia
    • Louise Pedersen
    • Magdalena Mazur-Milecka
    • Jacek Rumiński
    • Stefan Rahr Wagner
    2024 Machine Learning and Knowledge Extraction

    Previous reviews have investigated machine learning (ML) models used to predict the risk of developing preeclampsia. However, they have not addressed the intended deployment of these models throughout pregnancy, nor have they detailed feature performance. This study aims to provide an overview of existing ML models and their intended deployment patterns and performance, along with identified features of high importance. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. The search was performed in January and February 2024. It included all papers published before March 2024 obtained from the scientific databases: PubMed, Engineering Village, the Association for Computing Machinery, Scopus, and Web of Science. Of a total of 198 identified studies, 18 met the inclusion criteria. Among these, 11 showed the intent to use the ML model as a single-use tool, two intended a dual-use, and two intended multiple-use. Ten studies listed the features of the highest importance, with systolic and diastolic blood pressure, mean arterial pressure, and hypertension frequently mentioned as critical predictors. Notably, three of the four studies proposing dual or multiple-use models were conducted in 2023 and 2024, while the remaining study is from 2009. No single ML model emerged as superior across the subgroups of PE. Incorporating body mass index alongside hypertension and either mean arterial pressure, diastolic blood pressure, or systolic blood pressure as features may enhance performance. The deployment patterns mainly focused on single use during gestational weeks 11+0 to 14+1.

  • A Review on Metal–Organic Framework as a Promising Catalyst for Biodiesel Production ENERGY & FUELS
    • Giao Van Nguyen
    • Prabhakar Sharma
    • Marek Dzida
    • Van Hung Bui
    • Huu Son Le
    • Ahmed Shabana El-Shafay
    • Huu Cuong Le
    • Duc Trong Nguyen Le
    • Viet Dung Tran
    2024 ENERGY & FUELS

    The rapid depletion of fossil-derived fuels along with rising environmental pollution have motivated academics and manufacturers to pursue more environmentally friendly and sustainable energy options in today’s globe. Biodiesel has developed as an ecologically favorable alternative. However, the mass manufacturing of biodiesel on an industrial scale confronts substantial cost and pricing challenges. To address this issue, high-efficiency catalysts with a large number of active sites are needed, resulting in increased biodiesel output and quality. Metal–organic frameworks (MOFs) have received a lot of interest as a catalyst for converting oils/fats or fatty acids into biodiesel. MOFs are polyporous materials that can alter pore size as well as topological structure. They serve as a versatile foundation for designing active sites to satisfy the unique needs of catalytic reactions and conversion pathways. The purpose of this current work is to shed light on the underlying mechanisms and essential properties of MOF-based catalysts used in biodiesel synthesis. In addition, several methods for connecting active sites inside MOFs are scrutinized, while the properties and usability of MOF-based catalysts for the biodiesel production process are completely compared to other catalysts. More importantly, limits and future research directions about the utilization of MOFs in the biodiesel synthesis route are also critically presented. In general, this review contributes to improved awareness about the potential of MOFs in the biodiesel production sector by investigating the primary mechanism and characteristics of MOF-based catalysts.

  • A Robust Random Forest Model for Classifying the Severity of Partial Discharges in Dielectrics
    • Sayed Mohammad Kameli
    • Abdelaziz Abuelrub
    • Mohammad AlShaikh Saleh
    • Shady S. Refaat
    • Marek Olesz
    • Jarosław Guziński
    2024

    Partial Discharges (PDs) are a common source of degradation in electrical assets. It is essential that the extent of the deterioration level of insulating medium is correctly identified, to optimize maintenance schedules and prevent abrupt power outages. Temporal PD signals received from damaged insulation, collected through the IEC-60270 method is the gold standard for PD detection. Temporal signals may be transformed to the frequency domain, introducing new spectral features that may be beneficial in certain circumstances. Consequently, time delays are introduced, due to the high utilization of computational resources within the signal processing pipeline. Moreover, some microprocessors struggle with the excess computational burden demanded by resource-heavy mathematical transformations. To rectify these issues, an alternative approach is utilized, where Machine learning (ML) algorithms are directly used for the classification of PD severity. Cylindrically-shaped air cavities with lengths ranging from 1mm–6mm are introduced to a resin-based polyethylene terephthalate (PET) insulation material. The cavities are partitioned based on size, to obtain different classes of PD severity. A comparative analysis is performed on various ML algorithms, to determine which algorithm correctly determined the severity of PDs, with highest efficacy. Random Forest was determined to be the most performant, with an accuracy of 98.33%. The high performance illustrates the model’s potential success in accurately determining the hazard level of PDs in real-time, based on merely time-domain signals.

  • A Selection of Starting Points for Iterative Position Estimation Algorithms Using Feedforward Neural Networks
    • Jarosław Sadowski
    • Jacek Stefański
    2024 Full text SENSORS

    This article proposes the use of a feedforward neural network (FNN) to select the starting point for the first iteration in well-known iterative location estimation algorithms, with the research objective of finding the minimum size of a neural network that allows iterative position estimation algorithms to converge in an example positioning network. The selected algorithms for iterative position estimation, the structure of the neural network and how the FNN is used in 2D and 3D position estimation process are presented. The most important results of the work are the parameters of various FNN network structures that resulted in a 100% probability of convergence of iterative position estimation algorithms in the exemplary TDoA positioning network, as well as the average and maximum number of iterations, which can give a general idea about the effectiveness of using neural networks to support the position estimation process. In all simulated scenarios, simple networks with a single hidden layer containing a dozen non-linear neurons turned out to be sufficient to solve the convergence problem.

  • A semiempirical model for low energy electron–atom transport cross sections: The case of noble gases
    • Felipe Arretche
    • Eliton Popovicz Seidel
    • Wagner Tenfen
    2024 JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA

    A semiempirical approach to describe low energy electron–atom transport cross sections of easy implementation and reproduction is presented. The heart of the model is an energy independent two-parameter potential that was adjusted to reproduce the accurate total cross sections for He, Ne, Ar and Kr, measured with a threshold photoelectron source technique from meV up to 20 eV. Once the potential was conceived, the model was validated by comparing the values obtained for the calculated scattering lengths and phase shifts with the respective quantities previously reported in the literature. We close the article by presenting the momentum transfer and viscosity cross sections. Good agreement is found when compared to the similar data obtained from swarm experiments, from phase shifts according to differential cross section measurements and to the cross sections reported by sophisticated ab initio relativistic many-body calculations. Tables for the phase shifts and cross sections are provided for direct use and applications.

  • A simple and efficient hybrid discretization approach to alleviate membrane locking in isogeometric thin shells
    • Roger Sauer
    • Zhihui Zou
    • T.j.r. Hughes
    2024 COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING

    This work presents a new hybrid discretization approach to alleviate membrane locking in isogeometric finite element formulations for Kirchhoff–Love shells. The approach is simple, and requires no additional dofs and no static condensation. It does not increase the bandwidth of the tangent matrix and is effective for both linear and nonlinear problems. It combines isogeometric surface discretizations with classical Lagrange-based surface discretizations, and can thus be run with existing isogeometric finite element codes. Also, the stresses can be recovered straightforwardly. The effectiveness of the proposed approach in alleviating, if not eliminating, membrane locking is demonstrated through the rigorous study of the convergence behavior of several classical benchmark problems. Accuracy gains are particularly large in the membrane stresses. The approach is formulated here for quadratic NURBS, but an extension to other discretization types can be anticipated. The same applies to other constraints and associated locking phenomena.

  • A simple route of providing a soft interface for PEDOT: PSS film metallic electrodes without loss of their electrical interface parameters
    • Karolina Cysewska
    • Sylwia Pawłowska
    2024 ELECTROCHIMICA ACTA

    The work presents the development of a soft interface at PEDOT:PSS film without changing its electrical interface parameters. In the first step, PEDOT:PSS is electrodeposited on the commercial platinum electrode under the state-of-the-art conditions desirable for different electrochemical electrodes. Secondly, a pure hydrogel layer is deposited on the top of the electrodeposited PEDOT:PSS film under conditions that provide desirable mechanical properties (Young's modulus ∼10–20 kPa) and high permeability to ions from the solution. As a result, a PEDOT:PSS electrode with a soft interface desirable for different electrode applications is fabricated. The electrode exhibits electrical parameters at the same level as the state-of-the-art PEDOT:PSS film applied already for electrode applications. Moreover, the hydrogel layer additionally supports the polymeric film's electrochemical stability by inhibiting its oxidative degradation. The thickness of PEDOT film does not affect the overall electrochemical properties of the hydrogel electrode. The work shows that the specific choice of the hydrogel type and fabrication conditions allows to synthesis of the hydrogel interface on a stiff polymeric film, which does not block the ionic and electrical transfer. Moreover, the fabricated PEDOT:PSS electrode with hydrogel interface reveals interfacial impedance and potential window comparable or even better to the already published studies on PEDOT:PSS hydrogels.

  • A simplified channel estimation procedure for NB-IoT downlink
    • Jarosław Magiera
    2024 Full text

    This paper presents a low-complexity channel estimation procedure which is suitable for use in energy-efficient NB-IoT user equipment devices. The procedure is based on the well-established least squares scheme, followed by linear interpolation in the time domain and averaging in the frequency domain. The quality of channel estimation vs. signal-to-noise ratio is evaluated for two channel models and compared with the performance of channel estimation function implemented in the Matlab LTE Toolbox. The computational complexities of both implementations are assessed by measuring the average processing times required to obtain channel estimates for a given number of consecutive downlink frames. The results indicate that the proposed method provides a similar quality of channel estimation with considerably shorter processing time compared to its counterpart.

  • A Simplified SPWM Scheme for a Compact 3-Level Dual-Output Inverter
    • Charles Odeh
    • Arkadiusz Lewicki
    • Marcin Morawiec
    2024 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS

    Sinusoidal Pulse-width modulation, SPWM, is inverter-leg-based, logical-operation-based, and lesscomputational-intensive. In this brief, these simplifying features of SPWM are extended to the control of the 10-switch, 3-level inverter. The control strategy is based on the single triangular carrier SPWM perspective. Procedures and details of the sharing of four-common power switches by the 3 inverter legs are given. Classically, a 2-wing, 20-switch dual-output inverter, DOI, is configured; which topologically provides flexibility of independent operation of the constituting inverter wings at reduced component-count. This independent operation entails each of the inverter retaining full modulation index operational range (0 to unity) for the same or different frequencies of operation. Experimental demonstrations of the proposed SPWM scheme in the control of the 2-wing, 20-switch DOI are adequately presented.

  • A stochastic approach for the solution of single and multi – objective optimisation problems of biological processes in sequencing batch reactor
    • Tomasz Ujazdowski
    • Robert Piotrowski
    • Michał Banach
    2024 JOURNAL OF PROCESS CONTROL

    This paper investigates the impact of implementing single and multi-optimisation solutions on the biological treatment process in a sequencing batch reactor (SBR). The research is based on a case study of the water resource recovery facility (WRRF) in Swarzewo, Northern Poland. The paper introduces the adaptive extremum seeking control (ESC) method for dissolved oxygen (DO) concentration control and places it in a layered control structure. Further, it presents the introduction of an optimisation layer for the structure and parameters of the SBR cycle, through the synthesis of stochastic methods: single-objective optimisation (SOO) using a genetic algorithm (GA) and multi-objective optimisation (MOO) using the NSGA-II algorithm. The results were compared to a classical approach with fixed cycle parameters. The paper shows the advantages of optimising cycle parameters, including the number of phases as well as the DO value, on the process flow. These control structures underwent simulation tests in the MATLAB environment with the Simba package. The biochemical processes occurring in the reactor are based on the Activated Sludge Model No. 2d (ASM2d). The optimising control system demonstrates tangible improvements in operational efficiency and significant reductions in electrical energy consumption, highlighting the effectiveness of the proposed methodologies. © 2017 Elsevier Inc. All rights reserved.

  • A study of cavitation erosion resistance of an ion nitrided titanium alloy by means of the vibration and rotating disk methods
    • V.a. Safonov
    • Anna Zykova
    • Janusz Steller
    • Marek Szkodo
    • Grzegorz Gajowiec
    • Jarosław Chmiel
    • A. Varhoshkov
    2024 Full text Journal of Physics : Conference Series

    In this work, a comparative analysis of the cavitation erosion resistance of the Ti– 6.7Al–2.5Mo–1.8Cr–0.5Fe–0.25Si alloy (known as brand VT3-1) before and after lowtemperature ion nitriding is carried out. Two test methods were applied, using vibrative (ASTM G-32) and rotating disk rigs, respectively. The kinetic dependences of the erosive destruction of samples of titanium alloy VT3-1 in the initial state, after ion nitriding and stainless steel AISI 321 were obtained. A study of the microstructure, hardness and surface morphology was carried out. The samples were examined using optical and scanning electron microscopy. The relationship between mass loss and cavitation erosion duration was experimentally determined and analyzed. The erosion rate on a rotating disk stand is much higher than during vibration tests. A large cavitation load gradient provides additional opportunities for analyzing the durability of materials and coatings using this method.

  • A Study on the Effects of Cold Deformation on CMnSi Steel Structures Utilised in the Shipbuilding Industry
    • Van Nhanh Nguyen
    • Duong Nam Nguyen
    • Janusz Kozak
    • Xuan Phuong Nguyen
    • Dinh Tuyen Nguyen
    2024 Polish Maritime Research

    This article analyses the effects of deformation on the structure of CMnSi steel at various deformation levels. After hot forging, the structure of CMnSi steel comprises coarse-sized alpha and pearlite particles. The average grain size of steel after forging was 100 μm. After hot rolling, the grain size gradually decreases, with the average size of the ferrite and pearlite grains measured as 60 μm. After that, CMnSi steel was subjected to cold deformation at levels of 40%, 60%, and 80%. The grain size of the CMnSi steel sample after 80% cold deformation reached level 7, corresponding to about 25 μm. For a deformation level of 40%, the grain size was level 5, corresponding to 40 μm, while a deformation level of 60% produced a grain size of 35 μm, corresponding to level 6. In addition, scanning electron microscopy showed that after 80% deformation, smaller particles with a size of about 5 μm appear inside the parent particles. Moreover, energy-dispersive X-ray spectroscopy analysis revealed the carbide appearance in the form M23C6, with M being a mixture of Fe and Mn. These carbides have a fine size of about 1–2 μm and contribute to the prevention of particle growth during subsequent heat treatments.

  • A Survey on the Datasets and Algorithms for Satellite Data Applications
    • Michał Affek
    • Julian Szymanski
    2024 IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

    This survey compiles insights and describes datasets and algorithms for applications based on remote sensing. The goal of this review is twofold: datasets review for particular groups of tasks and high-level steps of data flow between satellite instruments and end applications from an implementation and development perspective. The article outlines the generalized data processing pipelines, taking into account the variations in data sources and intended use cases. It also provides an overview of the current satellite types, operational constellations, and the capabilities for onboard and ground processing. The review further compares popular datasets based on the specific objectives of their corresponding end applications. The comparison includes AI readiness information for the datasets. Particularly, between others, specification if they contain reproducible data splits or author's defined metrics. A study and explanation of the workflow are performed for the typical and experimental preprocessing pipelines and decision algorithms. These decision-making algorithms include artificial intelligence methods emphasizing deep learning algorithms for computer vision. A basic usage comparison of algorithms is performed for each defined task. In summary, the article presents the data flow from cameras and radars on satellite to end applications. It provides an in-depth analysis of selected scenarios that exemplify diverse approaches to extracting valuable information from data. These representative scenarios were picked to cover typical computational pipelines, for example, object detection or segmentation, and to list distinct approaches for obtaining versatile data-derived information.

  • A systematic review on cellular responses of Escherichia coli to nonthermal electromagnetic irradiation
    • Khadijeh Askaripour
    • Arkadiusz Żak
    2024 BIOELECTROMAGNETICS

    Investigation of Escherichia coli under electromagnetic fields is of significance in human studies owing to its short doubling time and human‐like DNA mechanisms. The present review aims to systematically evaluate the literature to conclude causality between 0 and 300 GHz electromagnetic fields and biological effects in E. coli. To that end, the OHAT methodology and risk of bias tool were employed. Exponentially growing cells exposed for over 30 min at temperatures up to 37C with fluctuations below 1C were included from the Web‐of‐Knowledge, PubMed, or EMF‐Portal databases. Out of 904 records identified, 25 articles satisfied the selection criteria, with four excluded during internal validation. These articles examined cell growth (11 studies), morphology (three studies), and gene regulation (11 studies). Most experiments (85%) in the included studies focused on the extremely low‐frequency (ELF) range, with 60% specifically at 50 Hz. Changes in growth rate were observed in 74% of ELF experiments and 71% of radio frequency (RF) experiments. Additionally, 80% of ELF experiments showed morphology changes, while gene expression changes were seen in 33% (ELF) and 50% (RF) experiments. Due to the limited number of studies, especially in the intermediate frequency and RF ranges, establishing correlations between EMF exposure and biological effects on E. coli is not possible.

  • A tool for designing water tanks for measuring hydroacoustic transducers
    • Roman Salamon
    • Jacek Marszal
    • Iwona Kochańska
    2024 Full text Vibrations in Physical Systems

    Special water tanks are commonly used to measure the parameters of underwater acoustic systems. They must meet specific requirements, the fulfilment of which ensures very small but acceptable measurement errors. These requirements define the size of the tank and its shape as well as the strong attenuation of reflected waves. At the design stage, it is necessary to determine the impact of the tank structure on the measurement errors and to adapt it to the expected measurement methodology. The article presents a mathematical tool for designing such water tanks using the impulse response method. Contrary to the use of this method in architectural design, the presented method is here used to determine the measurement signals emitted by ultrasonic transmitting transducers and received by receiving transducers. The relationships are given between the parameters of the impulse response and the design parameters of the tank and the measurement system, as well as its transfer functions and sample measurement signals.

  • A total scoring system and software for complex modified GAPI (ComplexMoGAPI) application in the assessment of method greenness
    • Fotouh R. Mansour
    • Khalid M. Omer
    • Justyna Płotka-Wasylka
    2024 Full text Green Analytical Chemistry

    Evaluating analytical methods with innovative metrics is essential to ensure the effectiveness of analytical procedures. Various approaches have been proposed to assess the performance of an analytical method and its environmental consequences, as sustainable environment and green chemistry ideology are of high importance nowadays. Considering greenness evaluation of developed analytical procedures, Green Analytical Procedure Index (GAPI), one of these metrics, utilizes five distinct colored pentagons to evaluate the environmental foot- print of the analytical process at different stages. An additional tool named Complementary Green Analytical Procedure Index (ComplexGAPI) was introduced to expand on GAPI by adding additional fields pertaining to the processes performed prior to the analytical procedure itself. Nevertheless, the existing ComplexGAPI lacks a comprehensive scoring system for individual methods, which would allow for even easier comparison of pro- cedures using this tool. In response to queries from ComplexGAPI users, this study introduces a refined tool named ComplexMoGAPI, merging the visual appeal of ComplexGAPI with precise total scores. The accompa- nying software streamlines the application, facilitating quicker and simpler evaluations. This software is avail- able as an open source on bit.ly/ComplexMoGAPI. We believe that, following ComplexGAPI success, this ComplexMoGAPI tool will also gain attention and eventually trust and acceptance from the chemical community.

  • Absorbing Boundary Conditions Derived Based on Pauli Matrices Algebra
    • Tomasz Stefański
    • Jacek Gulgowski
    • Kosmas L. Tsakmakidis
    2024 IEEE Antennas and Wireless Propagation Letters

    In this letter, we demonstrate that a set of absorbing boundary conditions (ABCs) for numerical simulations of waves, proposed originally by Engquist and Majda and later generalized by Trefethen and Halpern, can alternatively be derived with the use of Pauli matrices algebra. Hence a novel approach to the derivation of one-way wave equations in electromagnetics is proposed. That is, the classical wave equation can be factorized into two two-dimensional wave equations with first-order time derivatives. Then, using suitable approximations, not only Engquist and Majda ABCs can be obtained, but also generalized ABCs proposed by Trefethen and Halpern, which are applicable to simulations of radiation problems.

  • Accelerated remyelination and immune modulation by the EBI2 agonist 7α,25-dihydroxycholesterol analogue in the cuprizone model
    • Klaudia Konieczna-Wolska
    • Fionä Caratis
    • Mikołaj Opiełka
    • Karol Biernacki
    • Krzysztof Urbanowicz
    • Joanna Klimaszewska
    • Piotr Pobiarzyn
    • Oliwier Krajewski
    • Sebastian Demkowicz
    • Ryszard T. Smoleński
    • Bartosz Karaszewski
    • Klaus Seuwen
    • Aleksandra Rutkowska
    2024 BIOMEDICINE & PHARMACOTHERAPY

    Research indicates a role for EBI2 receptor in remyelination, demonstrating that its deficiency or antagonism inhibits this process. However, activation of EBI2 with its endogenous ligand, oxysterol 7α,25-dihydroxycholesterol (7α,25OHC), does not enhance remyelination beyond the levels observed in spontaneously remyelinating tissue. We hypothesized that the short half-life of the natural ligand might explain this lack of beneficial effects and tested a synthetic analogue, CF3-7α,25OHC, in the cuprizone model. The data showed that extending the bioavailability of 7α,25OHC is sufficient to accelerate remyelination in vivo. Moreover, the analogue, in contrast to the endogenous ligand, upregulated brain expression of Ebi2 and the synthesis of 15 lipids in the mouse corpus callosum. Mechanistically, the increased concentration of oxysterol likely disrupted its gradient in demyelinated areas of the brain, leading to the dispersion of infiltrating EBI2-expressing immune cells rather than their accumulation in demyelinated regions. Remarkably, the analogue CF3-7α,25OHC markedly decreased the lymphocyte and monocyte counts mimicking the key mechanism of action of some of the most effective disease-modifying therapies for multiple sclerosis. Furthermore, the Cd4+ transcripts in the cerebellum and CD4+ cell number in the corpus callosum were reduced compared to vehicle-treated mice. These findings suggest a mechanism by which EBI2/7α,25OHC signalling modulates the immune response and accelerates remyelination in vivo.

  • Accessibility to urban green spaces: A critical review of WHO recommendations in the light of tree-covered areas assessment
    • Patrycja Przewoźna
    • Adam Inglot
    • Marcin Mielewczyk
    • Krzysztof Mączka
    • Piotr Matczak
    2024 ECOLOGICAL INDICATORS

    Easy accessibility of Urban Green Spaces (UGSs) is essential to the quality of life in urban areas. The World Health Organization (WHO) recommendations focus on spatial access to UGSs, define as accessible those larger than 0.5 ha situated up to 300 m of residential areas, and disregard the social significance of smaller green spaces. This paper assesses the extent to which the WHO recommendations permit the identification of locations for tree-covered UGSs that serve urban residents. The study uses geo-questionnaire to collect data on residents’ perception of the ecosystem services (ESs) provided by trees in both small-sized (<0.5 ha) and larger (≥0.5 ha) UGSs in two Polish cities, Poznań and Gdańsk. Three factors impacting the social perception of UGS accessibility were controlled: (a) distance to trees (influencing reaching it by walk), (b) age, (c) the ESs provided by trees in both sizes of UGSs. The minority, i.e. 26 % of respondents valued trees in the larger UGSs. Regulating ecosystem services appeared significant there (mainly impact on health and well-being) and cultural ecosystem services, such as recreation. Most of the treecovered areas residents’ identified as significant were small-sized UGSs within the median distance of 150 m and were related to trees in residential areas and along the roadsides. Cultural ecosystem service − a sense of intimacy, separating from the neighbors, was specifically valued there. Age does not appear to be a major determinant of social perspectives on trees in UGSs. The results suggest that smallsized tree-covered UGSs are essential to residents and should be included in policies on urban greenery. In addition, the research findings indicate that identifying UGSs that are valuable from residents’ perspectives requires a comprehensive methodological approach. Limiting the assessment of the accessibility of such sites only to analyses based on the criterion of area and distance can offer narrow policy guidelines.

  • Accuracy of marine gravimetric measurements in terms of geodetic coordinates of land reference benchmark
    • Krzysztof Pyrchla
    • Kamil Łapiński
    • Jakub Szulwic
    • Wojciech Jurczak
    • Marek Przyborski
    • Jerzy Pyrchla
    2024 Full text Eksploatacja i Niezawodność - Maintenance and Reliability

    The article presents how the values of (3D) coordinates of land reference points affect the results of gravimetric measurements made from the ship in sea areas. These measurements are the basis for 3D maritime inertial navigation, improving ships' operational safety. The campaign verifying the network absolute point coordinates used as a reference point for relative marine gravity measurements was described. The obtained values were compared with catalogue values. In verification of network points 3D position the satellite data Global Satellite Navigation System (GNSS) and ground supporting systems (GBAS) was used. In this example, the height difference of the land reference point was 0.32 m. As a consequence, the offset budget of the marine campaign was affected in the range of up to 0.35 mGal. The influence on gravity free-air anomaly was not constant over the entire area covered by the campaign.

  • Accurate Post-processing of Spatially-Separated Antenna Measurements Realized in Non-Anechoic Environments
    • Adrian Bekasiewicz
    • Vorya Waladi
    • Tom Dhaene
    • Bartosz Czaplewski
    2024

    Antenna far-field performance is normally evaluated in expensive laboratories that maintain strict control over the propagation environment. Alternatively, the responses can be measured in non-anechoic conditions and then refined to extract the information on the structure field-related behavior. Here, a framework for correction of antenna measurements performed in non-anechoic test site has been proposed. The method involves automatic synchronization (in time-domain) of spatially separated measurements followed by their combination so as to augment the fraction of the signal that represents the antenna performance while suppressing the interferences. The method has been demonstrated based on six experiments performed in an office room. The performance improvement due to proposed post-processing amounts to 9.4 dB, which is represents up to over 5 dB improvement compared to the state-of-the-art methods.

  • Activated Tungsten Inert Gas Weld Characteristics of P91 Joint for Advanced Ultra Supercritical Power Plant Applications
    • Vishwa Bhanu
    • Dariusz Fydrych
    • Shailesh M. Pandey
    • Ankur Gupta
    • Chandan Pandey
    2024 JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE

    Activated Tungsten Inert Gas (A-TIG) welding, a variant of tungsten inert gas (TIG) welding, was used for welding P91. In Generation IV power plants, P91 welds are prone to premature failure due to the presence and formation of brittle phases and creep at high temperatures. When performing A-TIG welding, the flux composition plays a role in the reversal of the Marangoni flow in the weld pool, which ultimately determines the level of penetration achieved. A-TIG gave a complete penetration of 8 mm in the P91 weld. The weldment exhibited non-uniform growth of microstructures with varying grain sizes and precipitates, resulting in variation in mechanical properties. The weld fusion zone (WFZ) had a martensitic structure. The standard flat tensile test specimens were found to fail in the base metal and the fine-grain heat affected zone (FGHAZ) region. The sub-size flat tensile test specimen gave a high strength of 863 ± 10 MPa, failing in the WFZ. The high temperature tensile test specimens had the tensile strength of 512 ± 10 MPa (at 450 °C) and 469 ± 10 MPa (at 450 °C). In both the high temperature tensile test specimens, failure occurred in the base metal region. The impact toughness was recorded at 76 ± 15 Joules due to the presence of untempered martensite in the AW state, and in the PWHT state, the impact toughness increased up to 98 ± 15 Joules. In the AW state, the coarse grain heat affected zone (CGHAZ) region was observed with a maximum microhardness of 450 ± 5 HV and WFZ 460 ± 5 HV. The post-weld heat treatment (PWHT) was successfully performed to temper the martensite and impart some ductility to the weld. The A-TIG weld had sufficient benchmark strength, and the study successfully concluded its aim.

  • Active Diagnostic Experimentation on Wind Turbine Blades with Vibration Measurements and Analysis
    • Zbigniew Korczewski
    • Jacek Rudnicki
    2024 Full text Polish Maritime Research

    Paper deals with the key operational problems of wind turbosets, especially offshore, where vibrations are generated by rotor blades, as a consequence of erosive wear or icing. The primary causes of the imbalance of wind turbine rotors have been characterised, the observable symptoms of which include various forms of vibrations, transmitted from the turbine wheel to the bearing nodes of the power train components. Their identification was the result of an active diagnostic experiment, which actually entered the aerodynamic-mass imbalance of a turbine rotor into a wind power train, built as a small scale model. The recording of the observed monitoring parameters (vibration, aerodynamic, mechanical and electrical) made it possible to determine a set of symptoms (syndrome) of the deteriorated (entered) dynamic state of the entire wind turboset. This provides the basis for positive verification of the assumed concept and methodology of diagnostic testing, the constructed laboratory station and the measuring equipment used. For this reason, testing continued, taking into account the known and recognisable faults that most often occur during the operation of offshore wind turbosets. Transferring the results of this type of model research to full-size, real objects makes it possible to detect secondary (fatigue) damage to the elements transmitting torque from the wind turbine rotor to the generator early, especially the thrust bearings or gear wheel teeth.

  • Active Kriging-based conjugate first-order reliability method for highly efficient structural reliability analysis using resample strategy
    • Changqi Luo
    • Shun-Peng Zhu
    • Behrooz Keshtegar
    • Wojciech Macek
    • Ricardo Branco
    • Debiao Meng
    2024 COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING

    Efficient structural reliability analysis method is crucial to solving reliability analysis of complex structural problems. High-computational cost and low-failure probability problems greatly limit the efficiency in structural reliability analysis problems, causing the safety and reliability of the structure to be questioned. In this work, a highly efficient structural reliability analysis method coupling active Kriging algorithm with conjugate first order reliability method (AK-CFORM) is proposed. Specifically, the resample strategy is considered to reduce the number of samples evaluated in each active learning process; the uniform sampling is used to better balance global and local optimal problems; the conjugate map is used to improve the robustness of analytical first order reliability method; and the approximate numerical differential formula is proposed to solve the problems of non-convergence when solving the gradient of the Kriging surrogate model. Finally, three numerical cases and four engineering cases are used to illustrate the effectiveness and robustness of the proposed method. The results show that the proposed AK-CFORM has greater advantages in the number of calling system response and surrogate model with robust and accurate performance.

  • Active Learning on Ensemble Machine-Learning Model to Retrofit Buildings Under Seismic Mainshock-Aftershock Sequence
    • Neda Asgarkhani
    • Farzin Kazemi
    • Robert Jankowski
    2024

    This research presents an efficient computational method for retrofitting of buildings by employing an active learning-based ensemble machine learning (AL-Ensemble ML) approach developed in OpenSees, Python and MATLAB. The results of the study shows that the AL-Ensemble ML model provides the most accurate estimations of interstory drift (ID) and residual interstory drift (RID) for steel structures using a dataset of 2-, to 9-story steel structures considering four soil type effects. To prepare the dataset, 3584 incremental dynamic analysis (IDA) were performed on 64 structures. The research employs 6-, and 8-story structures to validate the AL-Ensemble ML model's effectiveness, showing it achieves the highest accuracy among conventional ML models, with an R2 of 98.4%. Specifically, it accurately predicts the RID of floor levels in a 6-story structure with an accuracy exceeding 96.6%. Additionally, the programming code identifies the specific damaged floor level in a building, facilitating targeted local retrofitting instead of retrofitting the entire structure promising a reduction in retrofitting costs while enhancing prediction accuracy.

  • Activity-based payments: alternative (anonymous) online payment model
    • Rafał Leszczyna
    2024 Full text International Journal of Information Security

    Electronic payments are the cornerstone of web-based commerce. A steady decrease in cash usage has been observed, while various digital payment technologies are taking over. They process sensitive personal information raising concerns about its potentially illicit usage. Several payment models that confront this challenge have been proposed. They offer varying levels of anonymity and readiness for adoption. The aim of this study was to broaden the portfolio with a solution that assures the highest level of anonymity and is well applicable. An empirical design research study with prototyping and conceptual research with a proposed construct were employed for this purpose. As a result, the Activity-Based Payment (ABP) model was proposed. It introduces a different mode of completing a payment transaction based on performing specific activities on a web location indicated by the payee. The anonymity properties of the solution, as well as its performance and applicability have been evaluated showing its particular suitability to micropayment and small payment scenarios.

  • Actual and reference evapotranspiration for a natural, temperate zone fen wetland – Upper Biebrza case study
    • Malgorzata Kleniewska
    • Tomasz Berezowski
    • Dorota Mitrowska
    • Sylwia Szporak-Wasilewska
    • Wojciech Ciezkowski
    2024 Full text Journal of Water and Land Development

    Evapotranspiration is the key and predominant component of the water balance in wetlands. Direct evapotranspiration measurements are challenging in wetlands due to their remoteness and high surface water level. This article describes the actual (ETa and reference evapotranspiration (ET0) from a cultivated wet meadow located in the Biebrza National Park – the largest national park in north-east Poland, Central Europe. The data were sourced from a micrometeorological station equipped with an eddy covariance system to measure heat and vapour fluxes and such meteorological elements as radiation balance components, air temperature and humidity. The values of directly measured ETa were presented daily in the context of available energy and ET0. Daily sums of ETa ranged from below 0.2 mm in winter to 6.5 mm in summer. The share of daily sums of ETa in the ET0 usually ranged from 50 to 60%, with extreme values from 10 to 170%. Aside from giving more insight into Biebrza wetlands’ functioning, the actual data produced in this study may be used instead of indirect methods, which were used the most in modelling wetlands areas.

  • Adapt Your Teacher: Improving Knowledge Distillation for Exemplar-free Continual Learning
    • Filip Szatkowski
    • Mateusz Pyła
    • Marcin Przewięźlikowski
    • Sebastian Cygert
    • Bartłomiej Twardowski
    • Tomasz Trzciński
    2024

    In this work, we investigate exemplar-free class incremental learning (CIL) with knowledge distillation (KD) as a regularization strategy, aiming to prevent forgetting. KDbased methods are successfully used in CIL, but they often struggle to regularize the model without access to exemplars of the training data from previous tasks. Our analysis reveals that this issue originates from substantial representation shifts in the teacher network when dealing with outof-distribution data. This causes large errors in the KD loss component, leading to performance degradation in CIL models. Inspired by recent test-time adaptation methods, we introduce Teacher Adaptation (TA), a method that concurrently updates the teacher and the main models during incremental training. Our method seamlessly integrates with KD-based CIL approaches and allows for consistent enhancement of their performance across multiple exemplar-free CIL benchmarks. The source code for our method is available at https://github.com/fszatkowski/cl-teacher-adaptation.

  • Adaptable management for cooling cyclic air in ship power plants by heat conversion – Part 1: Downsizing strategy for cogeneration plants
    • Roman Radchenko
    • Andrii Radchenko
    • Dariusz Mikielewicz
    • Mykola Radchenko
    • Anatoliy Pavlenko
    • Andrii Andreev
    2024 ENERGY

    The ship power plants (SPP) are generally based on Diesel engines. Their fuel efficiency is gradually sensible to cyclic air temperatures and drops with their rise. A sustainable performance of ship engines with high fuel efficiency is possible by cooling intake and charge air as two objects in waste heat conversion chillers. The peculiarities of marine engine application are associated with constrained space of machine room. Whereas, the chiller’s downsizing leads to inevitable lack of their cooling capacity and incomplete cooling air which results in reduction of fuel saving. The research objective is to develop the heat conversion management adaptable to balanced downsizing and fuel saving strategies due to flexible heat distribution between the chillers of different efficiencies (COP) in response to current thermal loads on engine cyclic air cooling system along the ship routes which enables to foresee a sustainable thermally stabilized and fuel saving operation of SPP. For the first time, such conflicting challenges are satisfied by flexible heat distribution between different chillers in response to intake and charge air cooling needs. The unique of such approach lies in unloading the high efficient but cumbersome chiller (absorption with COP about 0.7 as example) to boost the less efficient but easy to place in machine room ejector chiller (COP of about 0.2). The method of flexible heat distribution to minimize chiller sizes as constraints is realized in methodology based on step-by-step comparing the gap between heat demand and production to minimize shortage in fuel reduction simultaneously. It has been proved that cooling engine air by compact but less efficient ejector chiller (ECh) and high effective but cumbersome lithium bromide absorption chiller (ACh) of reduced capacity and sizes by about 30% accordingly provides a specific fuel consumption reduced by about 3%. The loss of route fuel saving by about 10% is considered as the "cost" for downsizing. These findings have been verified by the calculation results on current and summarized values of the cooling capacities lack, caused by the chiller’s downsizing, and fuel saving along the ship route. The novel strategy of heat conversion by combined chillers is especially useful for upgrading the existing engine air cooling system to implement it into the ship machine room.

  • Adaptacyjny system oświetlania dróg oraz inteligentnych miast
    • Tomasz Śmiałkowski
    2024 Full text

    Przedmiotem rozprawy jest zbadanie praktycznej możliwości wykrywania w czasie rzeczywistym anomalii w systemie oświetlenia drogowego w oparciu o analizę danych ze inteligentnych liczników energii. Zastosowanie inteligentnych liczników energii elektrycznej (Smart Meter) w systemach oświetlenia drogowego stwarza nowe możliwości w zakresie automatycznej diagnostyki takich niepożądanych zjawisk jak awarie lamp, odstępstwa od harmonogramu czy tez kradzieże energii z sieci zasilającej. Rozwiązanie takie wpisuje się w koncepcję inteligentnych miast (Smart City) gdzie zastosowanie adaptacyjnego systemu oświetlenia stwarza nowe wyzwania dla funkcji monitorowania. Zbadano metody uczenia maszynowego oparte o modele regresyjne oraz rekurencyjne sieci neuronowe. Zaproponowano praktyczne podejście oparte na zastosowaniu algorytmów czasu rzeczywistego, nienadzorowanych oraz używających ograniczonych zasobów obliczeniowych możliwych do implementacji w urządzeniach przemysłowych. Algorytmy przetestowano na rzeczywistych danych pochodzących z instalacji systemu oświetlenia i wykazano, że obie metody umożliwiają stworzenie samouczących algorytmów detekcji anomalii, działających w czasie rzeczywistym i że jest możliwa ich implementacja na urządzeniach warstwy Edge Computing. W rozprawie przedstawiono również architekturę uniwersalnej platformy sterowania elementami infrastruktury oświetleniowej opracowanej przy udziale autora, jako głównego konstruktora, w ramach projektu rozwojowego „INFOLIGHT - Chmurowa platforma oświetleniowa dla inteligentnych miast”.

  • Adaptacyjny system sterowania ruchem drogowym
    • Andrzej Sroczyński
    2024 Full text

    Adaptacyjny system sterowania ruchem drogowym to rodzaj systemu sterowania, który dynamicznie, w czasie rzeczywistym, dostosowuje swoje parametry w oparciu o bieżące warunki ruchu drogowego. Celem niniejszej rozprawy jest sprawdzenie wpływu wybranych cech systemu, zbudowanego w oparciu o zaprojektowane i zbudowane z udziałem autora inteligentne znaki drogowe, na wybrane parametry mające wpływ na bezpieczeństwo i płynność ruchu. W pierwszej kolejności zbadany został, na podstawie eksperymentu symulacyjnego, wpływ metody stopniowania redukcji prędkości na płynność ruchu. Drugim przedmiotem badań był wpływ odległości pomiędzy kolejnymi znakami ograniczenia prędkości na wariancję prędkości pojazdów. Ostatnim badanym aspektem była weryfikacja możliwości testowania modeli uczenia maszynowego, wytrenowanych na danych rzeczywistych, za pomocą danych syntetycznych, uzyskanych w drodze symulacji. Wyniki badań posłużyły do udowodnienia trzech tez badawczych, sformułowanych w niniejszej pracy. Praca zawiera ponadto rozdział w całości poświęcony opisowi praktycznej realizacji demonstratora adaptacyjnego systemu sterowania ruchem drogowym. Przedstawione zostały instalacje eksperymentalne oraz niektóre rezultaty badań terenowych, zaś dodatkiem do rozprawy jest przegląd konstrukcji opracowanych demonstratorów inteligentnych znaków drogowych.

  • Adaptive Hounsfield Scale Windowing in Computed Tomography Liver Segmentation
    • Maciej Zakrzewski
    • Dominik Kwiatkowski
    • Jan Cychnerski
    2024

    In computed tomography (CT) imaging, the Hounsfield Unit (HU) scale quantifies radiodensity, but its nonlinear nature across organs and lesions complicates machine learning analysis. This paper introduces an automated method for adaptive HU scale windowing in deep learning-based CT liver segmentation. We propose a new neural network layer that optimizes HU scale window parameters during training. Experiments on the Liver Tumor Segmentation Benchmark show that the learned window parameters often converge to a range encompassing clinically used windows but wider, suggesting that adjacent data may contain useful information for machine learning. This layer may enhance model efficiency with just 2 additional parameters.

  • Adaptive Hyperparameter Tuning within Neural Network-based Efficient Global Optimization
    • Taeho Jeong
    • Leifur Leifsson
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2024

    In this paper, adaptive hyperparameter optimization (HPO) strategies within the efficient global optimization (EGO) with neural network (NN)-based prediction and uncertainty (EGONN) algorithm are proposed. These strategies utilize Bayesian optimization and multiarmed bandit optimization to tune HPs during the sequential sampling process either every iteration (HPO-1itr) or every five iterations (HPO-5itr). Through experiments using the three-dimensional Hartmann function and evaluating both full and partial sets of HPs, adaptive HPOs are compared to traditional static HPO (HPO-static) that keep HPs constant. The results reveal that adaptive HPO strategies outperform HPOstatic, and the frequency of tuning and number of tuning HPs impact both the optimization accuracy and computational efficiency. Specifically, adaptive HPOs demonstrate rapid convergence rates (HPO-1itr at 28 iterations, HPO-5itr at 26 for full HPs; HPO-1itr at 13, HPO-5itr at 28 iterations for selected HPs), while HPO-static fails to approximate the minimum within the allocated 45 iterations for both scenarios. Mainly, HPO-5itr is the most balanced approach, found to require 21% of the time taken by HPO-1itr for tuning full HPs and 29% for tuning a subset of HPs. This work demonstrates the importance of adaptive HPO and sets the stage for future research.

  • Adaptive Optimal Discrete-Time Output-Feedback Using an Internal Model Principle and Adaptive Dynamic Programming
    • Zhongyang Wang
    • Youqing Wang
    • Zdzisław Kowalczuk
    2024 IEEE-CAA Journal of Automatica Sinica

    In order to address the output feedback issue for linear discrete-time systems, this work suggests a brand-new adaptive dynamic programming (ADP) technique based on the internal model principle (IMP). The proposed method, termed as IMP-ADP, does not require complete state feedback, merely the measurement of input and output data. More specifically, based on the IMP, the output control problem can first be converted into a stabilization problem. We then design an observer to reproduce the full state of the system by measuring the inputs and outputs. Moreover, includes both a policy iteration algorithm and a value iteration algorithm to determine the optimal feedback gain without using a dynamic system model. It is important that in this concept you do not need to solve the regulator equation. Finally, this control method was tested on an inverter system of grid-connected LCLs to demonstrate that the proposed method provides the desired performance in terms of both tracking and disturbance rejection.

  • Adaptive Sampling for Non-intrusive Reduced Order Models Using Multi-Task Variance
    • Abhijnan Dikshit
    • Leifur Leifsson
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2024

    Non-intrusive reduced order modeling methods (ROMs) have become increasingly popular for science and engineering applications such as predicting the field-based solutions for aerodynamic flows. A large sample size is, however, required to train the models for global accuracy. In this paper, a novel adaptive sampling strategy is introduced for these models that uses field-based uncertainty as a sampling metric. The strategy uses Monte Carlo simulations to propagate the uncertainty in the prediction of the latent space of the ROM obtained using a multitask Gaussian process to the high-dimensional solution of the ROM. The high-dimensional uncertainty is used to discover new sampling locations to improve the global accuracy of the ROM with fewer samples. The performance of the proposed method is demonstrated on the environment model function and compared to one-shot sampling strategies. The results indicate that the proposed adaptive sampling strategies can reduce the mean relative error of the ROM to the order of 8 × 10−4 which is a 20% and 27% improvement over the Latin hypercube and Halton sequence sampling strategies, respectively at the same number of samples.

  • Additive manufacturing of Proton-Conducting Ceramics by robocasting with integrated laser postprocessing
    • Joanna Pośpiech
    • Małgorzata Nadolska-Dawidowska
    • Mateusz Cieślik
    • Tomasz Sobczyk
    • Marek Chmielewski
    • Aleksandra Mielewczyk-Gryń
    • Ragnar Strandbakke
    • José M Serra
    • Sebastian Wachowski
    2024 Full text Applied Materials Today

    A hybrid system combining robocasting and NIR laser postprocessing has been designed to fabricate layers of mixed proton-electron conducting Ba0.5La0.5Co1-xFexO3-δ ceramic. The proposed manufacturing technique allows for the control of the geometry and microstructure and shortens the fabrication time to a range of a few minutes. Using 5 W laser power and a scanning speed of 500 mm⋅s− 1, sintering of a round-shaped layer with an 8 mm radius was performed in less than 2 s. The single phase of the final product was confirmed by X-ray diffraction. Various ceramic-to-polymer weight ratios were tested, showing that various porosities of microstructures of ~30 - 35 % and ~19 % can be obtained with 2:1 and 4:1 loading respectively.