2020 - Repozytorium publikacji - Politechnika Gdańska

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A Subspace-Splitting Moment-Matching Model-Order Reduction Technique for Fast Wideband FEM Simulations of Microwave Structures
- Damian Szypulski
- Grzegorz Fotyga
- Valentin de la Rubia
- Michał Mrozowski
2020 Pełny tekst IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
This article describes a novel model-order reduction (MOR) approach for efficient wide frequency band finite-element method (FEM) simulations of microwave components. It relies on the splitting of the system transfer function into two components: a singular one that accounts for the in-band system poles and a regular part that has no in-band poles. In order to perform this splitting during the reduction process, the projection basis is formed of two sets of orthogonal vectors that must be computed in sequence. The first set to be computed consists of the in-band eigenvectors that are associated with the dynamics of the electromagnetic field, while the second set uses the block moments of the original system, which are computed in the orthogonal complement to the subspace spanned by the in-band eigenvectors. The advantage of this method is that it results in a more compact reduced-order model than a method that employs only moment matching for the projection basis computations.
A survey of neural networks usage for intrusion detection systems
- Anna Drewek-Ossowicka
- Mariusz Pietrołaj
- Jacek Rumiński
2020 Pełny tekst Journal of Ambient Intelligence and Humanized Computing
In recent years, advancements in the field of the artificial intelligence (AI) gained a huge momentum due to the worldwide appliance of this technology by the industry. One of the crucial areas of AI are neural networks (NN), which enable commer‐ cial utilization of functionalities previously not accessible by usage of computers. Intrusion detection system (IDS) presents one of the domains in which neural networks are widely tested for improving overall computer network security and data privacy. This article gives a thorough overview of recent literature regarding neural networks usage in intrusion detection system area, including surveys and new method proposals. Short tutorial descriptions of neural network architectures, intrusion detection system types and training datasets are also provided.
A Theoretical and Experimental Study of Moderate Temperature Alfa Type Stirling Engines
- Jacek Kropiwnicki
- Mariusz Furmanek
2020 Pełny tekst ENERGIES
The Stirling engine is a device that allows conversion of thermal energy into mechanical energy with relatively high efficiency. Existing commercial designs are mainly based on the usage of high temperature heat sources, whose availability from renewable or waste heat sources is significantly lower than that of moderate temperature sources. The paper presents the results of experimental research on a prototype alpha type Stirling engine powered by a moderate temperature source of heat. Obtained results enabled calibration of the evaluated theoretical model of the Stirling engine. The model of the engine has been subsequently used for the analysis of regenerator effectiveness influenced by the charge pressure and the heating temperature. Performed study allowed to determine further development directions of the prototype engine to improve its power and efficiency. As a result of optimization, worked out design will potentially increase the indicated efficiency up to 19.5% (5.5% prototype) and the indicated power up to 369 W (114 W prototype).
A Universal Theory of Wisdom . A Mind - oriented Approach
- Henryk Krawczyk
- Andrew Targowski
2020 DIALOGUE AND UNIVERSALISM
The purpose of the paper is to synthesize the issues of human wisdom in terms of minds which create knowledge-based judgment. We form a transdisciplinary, big-picture view of the wisdom of humans. Findings: Wisdom is the right judgment and choice in the context of the art of living. Practical implications: Wisdom can be developed within the set of minds. Social implications: To pursue wisdom in thinking and action, one must extend education to embrace more knowledge and practicing gaining better skills in decision-making. Originality: This approach offers a new understanding of the wisdom of humans, which cannot be identified as a synonym of knowledge.
A vector-enzymatic DNA fragment amplification-expression technology for construction of artificial, concatemeric DNA, RNA and proteins for novel biomaterials, biomedical and industrial applications
- Piotr Skowron
- Natalia Krawczun
- Joanna Żebrowska
- Daria Krefft
- Olga Żołnierkiewicz
- Marta Bielawa
- Joanna Jeżewska-Frąckowiak
- Łukasz Janus
- Małgorzata Witkowska
- Małgorzata Palczewska
- Adriana Schumacher
- Anna Wardowska
- Milena Deptuła
- Artur Czupryn
- Piotr Mucha
- Arkadiusz Piotrowski
- Paweł Sachadyn
- Sylwia Rodziewicz-Motowidło
- Michal Pikuła
- Agnieszka Zylicz-Stachula
2020 Materials Science & Engineering C-Materials for Biological Applications
A DNA fragment amplification/expression technology for the production of new generation biomaterials for scientific, industrial and biomedical applications is described. The technology enables the formation of artificial Open Reading Frames (ORFs) encoding concatemeric RNAs and proteins. It recruits the Type IIS SapI restriction endonuclease (REase) for an assembling of DNA fragments in an ordered head-to-tail-orientation. The technology employs a vector-enzymatic system, dedicated to the expression of newly formed, concatemeric ORFs from strong promoters. Four vector series were constructed to suit specialised needs. As a proof of concept, a model amplification of a 7-amino acid (aa) epitope from the S protein of HBV virus was performed, resulting in 500 copies of the epitope-coding DNA segment, consecutively linked and expressed in Escherichia coli (E. coli). Furthermore, a peptide with potential pro-regenerative properties (derived from an angiopoietin-related growth factor) was designed. Its aa sequence was back-translated, codon usage optimized and synthesized as a continuous ORF 10-mer. The 10-mer was cloned into the amplification vector, enabling the N-terminal fusion and multiplication of the encoded protein with MalE signal sequence. The obtained genes were expressed, and the proteins were purified. Conclusively, we show that the proteins are neither cytotoxic nor immunogenic and they have a very low allergic potential.
A Wind Energy Conversion System Based on a Generator with Modulated Magnetic Flux
- Michał Gwóźdź
- Michał Krystkowiak
- Łukasz Ciepliński
- Ryszard Strzelecki
2020 Pełny tekst ENERGIES
In this work, the concept of an energy conversion system for wind turbines based on the modified permanent magnet synchronous generator (PMSG) is presented. In the generator, a pair of three-phase windings is used, one of which is connected in a “star” and the second in a “delta” configuration. At the outputs of both windings, two six-pulse uncontrolled (diode) rectifiers are included. These rectifiers are mutually coupled by a specially designed pulse transformer, whose primary winding is powered by the power electronics converter—the so-called “current modulator”—which, in this case, operates as a magnetic flux modulator, in the generator. The modulator provides a quasi-sinusoidal magnetomotive force (mmf) in the stator of the machine. The whole system is connected to the power grid via a dedicated voltage source inverter (VSI) converter. The main objective of the elaborated solution is to provide high efficiency conversion of mechanical (wind) energy into electricity by means of a relatively simple electrical system.
Abdominal Aortic Aneurysm segmentation from contrast-enhanced computed tomography angiography using deep convolutional networks
- Tomasz Dziubich
- Paweł Białas
- Łukasz Znaniecki
- Joanna Halman
- Jakub Brzeziński
2020
One of the most common imaging methods for diagnosing an abdominal aortic aneurysm, and an endoleak detection is computed tomography angiography. In this paper, we address the problem of aorta and thrombus semantic segmentation, what is a mandatory step to estimate aortic aneurysm diameter. Three end-to-end convolutional neural networks were trained and evaluated. Finally, we proposed an ensemble of deep neural networks with underlying U-Net, ResNet, and VBNet frameworks. Our results show that we are able to outperform state-of-the-art methods by 3% on the Dice metric without any additional post-processing steps.
Absolute Photoabsorption Cross-Sections of Methanol for Terrestrial and Astrophysical Relevance
- Emanuele Lange
- Ana Lozano
- Nykola C. Jones
- Søren Hoffmann
- Sarvesh Kumar
- Małgorzata Śmiałek-Telega
- Denis Duflot
- Michael J. Brunger
- Paulo Limão-Vieira
2020 Pełny tekst JOURNAL OF PHYSICAL CHEMISTRY A
We investigate the methanol absorption spectrum in the range 5.5–10.8 eV to provide accurate and absolute cross-sections values. The main goal of this study is to provide a comprehensive analysis of methanol electronic-state spectroscopy by employing high-resolution vacuum ultraviolet (VUV) photoabsorption measurements together with state-of-the-art quantum chemical calculation methods. The VUV spectrum reveals several new features that are not previously reported in literature, for n > 3 in the transitions (nsσ(a′) ← (2a″)) (1A′ ← X̃1A′) and (nsσ, npσ, npσ′, ndσ ← (7a′)) (1A′ ← X̃1A′), and with particular relevance to vibrational progressions of the CH3 rocking mode, v11′(a″), mode in the (3pπ(a″) ← (2a″)) (21A′ ← X̃1A′) absorption band at 8.318 eV. The measured absolute photoabsorption cross-sections have subsequently been used to calculate the photolysis lifetime of methanol in the Earth’s atmosphere from the ground level up to the limit of the stratosphere (50 km altitude). This shows that solar photolysis plays a negligible role in the removal of methanol from the lower atmosphere compared with competing sink mechanisms. Torsional potential energy scans, as a function of the internal rotation angle for the ground and first Rydberg states, have also been calculated as part of this investigation.
Absolwent Wydziału Mechanicznego Złotym Inżynierem "Przeglądu Technicznego"
- Adam Barylski
2020 Pismo PG
Przedstawiono sylwetke i dorobek mgr. inż. Janusza Ochocińskiego, tegorocznego laureata plebiscytu czasopima "Przegląd Techniczny", o tytuł Złotego Inżyniera 2019 w kategorii Menedżer. Pan Janusz Ochociński jest absolwentem Wydziału Mechanicznego Technologicznego Politechniki Gdańskiej z roku 1981.
Absorptive Desulfurization of Model Biogas Stream Using Choline Chloride-Based Deep Eutectic Solvents
- Edyta Słupek
- Patrycja Makoś
2020 Pełny tekst Sustainability
The paper presents a synthesis of deep eutectic solvents (DESs) based on choline chloride (ChCl) as hydrogen bond acceptor and phenol (Ph), glycol ethylene (EG), and levulinic acid (Lev) as hydrogen bond donors in 1:2 molar ratio. DESs were successfully used as absorption solvents for removal of dimethyl disulfide (DMDS) from model biogas steam. Several parameters affecting the absorption capacity and absorption rate have been optimized including kinds of DES, temperature, the volume of absorbent, model biogas flow rate, and initial concentration of DMDS. Furthermore, reusability and regeneration of DESs by means of adsorption and nitrogen barbotage followed by the mechanism of absorptive desulfurization by means of density functional theory (DFT) as well as FT-IR analysis were investigated. Experimental results indicate that the most promising DES for biogas purification is ChCl:Ph, due to high absorption capacity, relatively long absorption rate, and easy regeneration. The research on the absorption mechanism revealed that van der Waal interaction is the main driving force for DMDS removal from model biogas
Accelerated design optimization of miniaturized microwave passives by design reusing and Kriging interpolation surrogates
- Anna Pietrenko-Dąbrowska
- Sławomir Kozieł
2020 Pełny tekst AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
Electromagnetic (EM) analysis has become ubiquitous in the design of microwave components and systems. One of the reasons is the increasing topological complexity of the circuits. Their reliable evaluation—at least at the design closure stage—can no longer be carried out using analytical or equivalent network representations. This is especially pertinent to miniaturized structures, where considerable EM cross-coupling effects occurring in densely arranged layouts affect the performance in a non-negligible manner. Although mandatory, EM-driven design is normally associated with significant computational expenses. Consequently, expediting the procedures that require massive simulations, such as parametric optimization, is a practical necessity. In this paper, a framework for accelerated parameter tuning is proposed. The keystones of our methodology are a set of pre-existing designs optimized for various design objectives, as well as kriging interpolation surrogates. The latter are constructed to yield—for a given set of performance specifications—a reasonably good starting point and to enable rapid optimization by providing the initial approximation of the Jacobian matrix of the circuit outputs. The proposed approach is validated using two compact impedance matching transformers designed within the objective spaces defined by wide ranges of operating bandwidths. As demonstrated, the average tuning cost corresponds to a few EM simulations of the respective circuit despite large numbers of adjustable parameters.
Accelerated multi-objective design of miniaturized microwave components by means of nested kriging surrogates
- Anna Pietrenko-Dąbrowska
- Sławomir Kozieł
2020 Pełny tekst INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING
Design of microwave components is an inherently multiobjective task. Often, the objectives are at least partially conflicting and the designer has to work out a suitable compromise. In practice, generating the best possible trade‐off designs requires multiobjective optimization, which is a computationally demanding task. If the structure of interest is evaluated through full‐wave electromagnetic (EM) analysis, the employment of widely used population‐based metaheuristics algorithms may become prohibitive in computational terms. This is a common situation for miniaturized components, where considerable cross‐coupling effects make traditional representations (eg, network equivalents) grossly inaccurate. This article presents a framework for accelerated EM‐driven multiobjective design of compact microwave devices. It adopts a recently reported nested kriging methodology to identify the parameter space region containing the Pareto front and to render a fast surrogate, subsequently used to find the first approximation of the Pareto set. The final trade‐off designs are produced in a separate, surrogate‐assisted refinement process. Our approach is demonstrated using a three‐section impedance matching transformer designed for the best matching and the minimum footprint area. The Pareto set is generated at the cost of only a few hundred of high‐fidelity EM simulations of the transformer circuit despite a large number of geometry parameters involved.
Accelerated Re-Design of Antenna Structures Using Sensitivity-Based Inverse Surrogates
- Sławomir Kozieł
- Adrian Bekasiewicz
2020 Pełny tekst IEEE Access
The paper proposes a novel framework for accelerated re-design (dimension scaling) of antenna structures using inverse surrogates. The major contribution of the work is a sensitivity-based model identification procedure, which permits a significant reduction of the number of reference designs required to render the surrogate. Rigorous formulation of the approach is supplemented by its comprehensive numerical validation using a triple-band uniplanar dipole antenna and a dual-band monopole antenna re-designed with respect to operating frequencies as well as the substrate parameters (thickness and dielectric permittivity). It is demonstrated that—for the considered test cases—the reliable inverse model can be set up using a significantly smaller (by a factor of three) number of reference points as compared to the original version of the method, whereas the dimension scaling process itself requires up to four EM simulations of the antenna structure.
Accuracy of Trajectory Tracking Based on Nonlinear Guidance Logic for Hydrographic Unmanned Surface Vessels
- Andrzej Stateczny
- Paweł Burdziakowski
- Klaudia Najdecka
- Beata Domagalska-Stateczna
2020 Pełny tekst SENSORS
A new trend in recent years for hydrographic measurement in water bodies is the use of unmanned surface vehicles (USVs). In the process of navigation by USVs, it is particularly important to control position precisely on the measuring profile. Precise navigation with respect to the measuring profile avoids registration of redundant data and thus saves time and survey costs. This article addresses the issue of precise navigation of the hydrographic unit on the measuring profile with the use of a nonlinear adaptive autopilot. The results of experiments concerning hydrographic measurements performed in real conditions using an USV are discussed.
Accurate Computation of IGBT Junction Temperature in PLECS
- Paweł Górecki
- Daniel Wojciechowski
2020 IEEE TRANSACTIONS ON ELECTRON DEVICES
In the article, a new method to improve the accuracy of the insulated-gate bipolar transistor (IGBT) junction temperature computations in the piecewise linear electrical circuit simulation (PLECS) software is proposed and described in detail. This method allows computing the IGBT junction temperature using a nonlinear compact thermal model of this device in PLECS. In the method, a nonlinear compact thermal model of the IGBT is used, which considers the dependence of thermal resistance on the junction temperature. The usefulness of the method is experimentally verified, and it is confirmed that it increases the accuracy of the computations and shortens their time. The differences between the measured and computed characteristics are discussed. The application of the developed method for computations resulted in a significant reduction of their error to only a few percent. The developed method can be applied in the system-level simulations of the power electronics converters.
‘Acridines’ as New Horizons in Antifungal Treatment
- Iwona Gabriel
2020 Pełny tekst MOLECULES
Frequent fungal infections in immunocompromised patients and mortality due to invasive mycosis are important clinical problems. Opportunistic pathogenic Candida species remain one of the leading causes of systemic mycosis worldwide. The repertoire of antifungal chemotherapeutic agents is very limited. Although new antifungal drugs such as lanosterol 14α-demethylase and β-glucan synthase inhibitors have been introduced into clinical practice, the development of multidrug resistance has become increasingly significant. The urgency to expand the range of therapeutic options for the treatment of fungal infections has led researchers in recent decades to seek alternative antifungal targets to the conventional ones currently used. Among them, many compounds containing an acridine scaffold have been synthesized and tested. In this review, the applicability of acridines and their functional analogues acridones as antifungal agents is described. Acridine derivatives usage in photoantifungal chemotherapy, interactions with fungal transporters resulting in modulation of efflux/influx pumps and the effect of acridine derivatives on fungal topoisomerases are discussed. This article explores new perspectives on the mechanisms of antifungal acridine-peptide conjugates and acridine-based hybrid molecules to effectively combat fungal infections.
Activated Carbon Produced by Pyrolysis of Waste Wood and Straw for PotentialWastewater Adsorption
- Katarzyna Januszewicz
- Paweł Kazimierski
- Maciej Klein
- Dariusz Kardaś
- Justyna Łuczak
2020 Pełny tekst Materials
Pyrolysis of straw pellets and wood strips was performed in a fixed bed reactor. The chars, solid products of thermal degradation, were used as potential materials for activated carbon production. Chemical and physical activation processes were used to compare properties of the products. The chemical activation agent KOH was chosen and the physical activation was conducted with steam and carbon dioxide as oxidising gases. The eect of the activation process on the surface area, pore volume, structure and composition of the biochar was examined. The samples with the highest surface area (1349.6 and 1194.4 m2/g for straw and wood activated carbons, respectively) were obtained when the chemical activation with KOH solution was applied. The sample with the highest surface area was used as an adsorbent for model wastewater contamination removal.
Activation of N2O and SO2 by the P–B Bond System. Reversible Binding of SO2 by the P–O–B Geminal Frustrated Lewis Pair
- Natalia Szynkiewicz
- Jarosław Chojnacki
- Rafał Grubba
2020 Pełny tekst INORGANIC CHEMISTRY
Herein, we present the first transformation of borylphosphine into borylphosphinite using nitrous oxide. Borylphosphine reacts with N2O via insertion of a single oxygen atom into the P−B bond and formation of a P−O−B bond system. Borylphosphine and borylphosphinite capture SO2 and activate it in an irreversible and reversible manner, respectively.
Activation of peroxymonosulfate using carbon black nano-spheres/calcium alginate hydrogel matrix for degradation of acetaminophen: Fe3O4 co-immobilization and microbial community response
- Reza Darvishi Cheshmeh Soltani
- Mansoureh Mahmoudi
- Grzegorz Boczkaj
- Alireza Khataee
2020 Pełny tekst JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
Herein, we focused on the degradation of acetaminophen (ACT) drug in liquid phase by peroxymonosulfate (PMS) activated by carbon black nano-spheres (CBNS). The nanostructured activator was immobilized into calcium alginate hydrogel matrix (CAHM) to avoid the washout of the fine nanostructures. The Langmuir modeling showed an insignificant contribution to the adsorption process in the removal of ACT. The basic pH conditions favored the decomposition of ACT. Among nutrients, the presence of nitrogenous compounds including nitrite, nitrate and ammonium caused a little decrease in the reactor performance, while the addition of phosphate ion improved the efficiency from 76.8 to 81.9%. The results demonstrated the involvement of both SO4•− and •OH radicals in the degradation of ACT and domination of SO4•− radicals in the degradation process. Co-immobilization of the CBNS with electro-synthesized magnetite nanoparticles resulted in not only the enhanced reusability potential but also improved the efficiency of the treatment process to 95.6%. Mineralization efficiency of the process was not remarkable; however, the process produced an effluent with lower toxicity toward the microbial community of the activated sludge.
Adapting Agile Practices to Security Context – Practitioners’ Perspective
- Katarzyna Łukasiewicz
- Sara Cygańska
2020
In this paper we explore the problem of introducing agile practices to projects dealing with systems with high security requirements. We also propose an approach based on AgileSafe method and OWASP ASVS guidelines, that could support such introduction. What is more, we present the results of two surveys aimed at analyzing IT practitioners’ views on applying agile methods to security reliant systems as well as evaluating the set of agile security-oriented practices which are a part of the proposed approach. This paper is an extended version of the paper “Security-oriented agile approach with AgileSafe and OWASP ASVS” that was published as a part of LASD 2019 conference proceedings