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Investigation of praseodymium and samarium co-doped ceria as an anode catalyst for DIR-SOFC fueled by biogas
PublicationThe Pr and Sm co-doped ceria (with up to 20 mol.% of dopants) compounds were examined as catalytic layers on the surface of SOFC anode directly fed by biogas to increase a lifetime and the efficiency of commercially available DIR-SOFC without the usage of an external reformer. The XRD, SEM and EDX methods were used to investigate the structural properties and the composition of fabricated materials. Furthermore, the electrical...
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Wojciech Litwin dr hab. inż.
People1992÷1996 - study on Mechanical Department at Gdansk University of Technology1996 – employed in the Faculty of Ocean Engineering and Ship Technology at the Gdansk University of Technology2004 – PhD2014 – habilitation2016 - vice dean for science at Faculty of Ocean Engineering2020 - dean of the Faculty of Ocean Engineering2021 - head of Institute of Naval Architecture He participated in a number of designing and research programs...
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Numerical Methods
e-Learning CoursesNumerical Methods: for Electronics and Telecommunications students, Master's level, semester 1 Instructor: Michał Rewieński, Piotr Sypek Course description: This course provides an introduction to computational techniques for the simulation and modeling of a broad range of engineering and physical systems. Concepts and methods discussed are widely illustrated by various applications including modeling of integrated circuits,...
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POLLUTANTS PRESENT IN DIFFERENT COMPONENTS OF THE SVALBARD ARCHIPELAGO ENVIRONMENT
PublicationDuring last years an interest in the processes of transport and fate of pollutants to the polar regions located distantly from industrial centers, has significantly increased. The current analytical techniques enabling conducting studies prove that the Arctic regions (in the past considered as a pollution free area) have become an area of highly intensive anthropopresion. Svalbard archipelago stands out from the other polar regions...
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Collagen Type II—Chitosan Interactions as Dependent on Hydroxylation and Acetylation Inferred from Molecular Dynamics Simulations
PublicationChitosan–collagen blends have been widely applied in tissue engineering, joints diseases treatment, and many other biomedical fields. Understanding the affinity between chitosan and collagen type II is particularly relevant in the context of mechanical properties modulation, which is closely associated with designing biomaterials suitable for cartilage and synovial fluid regeneration. However, many structural features influence...
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Emotional distress, burnout and sense of safety during the COVID-19 pandemic in teachers after the reopening of schools
PublicationThe COVID-19 pandemic is having a significant impact on people's psychological well-being and mental health. This study aimed to identify factors linked to emotional distress, burnout and sense of safety in teachers related to the reopening of Polish schools after lockdown, remote work, and the holiday period between March and August 2020. A total of 1,286 teachers from different educational institutions participated in the...
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Diffusible Hydrogen Control in Flux Cored Arc Welding Process
PublicationOne of the types of hydrogen degradation of steel welded joints is cold cracking. The direct cause of the formation of cold cracks is simultaneous presence of hydrogen, residual stresses and brittle structure. The way of preventing the occurring of degradation is to eliminate at least one of these factors. Practice has shown that the best solution is to control the amount of hydrogen in deposited metal. In this paper an experimental...
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Two-Step Model Based Adaptive Controller for Dissolved Oxygen Control in Sequencing Wastewater Batch Reactor
PublicationDissolved Oxygen (DO) concentration is a crucial parameter for efficient operation of biological processes taking place in the activated sludge Wastewater Treatment Plant (WWTP). High-quality DO control is difficult to achieve because of complex nonlinear behavior of the plant and substantial influent disturbances. A method to improve the Direct Model Reference Adaptive Control (DMRAC) technology in application to DO tracking for...
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Rough Set Based Modeling and Visualization of the Acoustic Field Around the Human Head
PublicationThe presented research aims at modeling acoustical wave propagation phenomena by applying rough set theory in a novel manner. In a typical listening environment sound intensity is determined by numerous factors: a distance from a sound source, signal levels and frequencies, obstacles’ locations and sizes. Contrarily, a free-field is characterized by direct, unimpeded propagation of the acoustical waves. The proposed approach is...
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Microbiological Survey in Two Arctic Fjords: Total Bacterial Number and Biomass Comparison of Hornsund and Kongsfjorden
PublicationTwo microbiological parameters: total bacterial number (TBN) and biomass (BBM) were studied in two Arctic fjords: Hornsund and Kongsfjorden. Samples were collected from three sampling points in each fjord, from various water depth layers: from the surface to 75 m depth. Total bacterial number and biomass were examined using the DAPI staining and direct count method. The greater amount of bacteria, as well as highest bacterial biomass...
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Microbiological Survey in Two Arctic Fjords: Total Bacterial Number and Biomass Comparison of Hornsund and Kongsfjorden
PublicationTwo microbiological parameters: total bacterial number (TBN) and biomass (BBM) were studied in two Arctic fjords: Hornsund and Kongsfjorden. Samples were collected from three sampling points in each fjord, from various water depth layers: from the surface to 75 m depth. Total bacterial number and biomass were examined using the DAPI staining and direct count method. The greater amount of bacteria, as well as highest bacterial biomass...
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Method for universal detection of two-photon polarization entanglement
PublicationDetecting and quantifying quantum entanglement of a given unknown state poses problems that are fundamentally important for quantum information processing. Surprisingly, no direct (i.e., without quantum tomography) universal experimental implementation of a necessary and sufficient test of entanglement has been designed even for a general two-qubit state. Here we propose an experimental method for detecting a collective universal...
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Multivariate analysis of impedance data obtained for coating systems of varying thickness applied on steel
PublicationElectrochemical impedance spectroscopy (EIS) has proven to be a valuable test method for the electrochemical characterization of protective coatings on metals. The common way of analysis in impedance spectroscopy is to model the impedance spectrum by means of an equivalent circuit and to extract the quantity of interest using optimization techniques. A model, corresponding to the behavior of the sample under testing, is important...
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Coastline change-detection method using remote sensing satellite observation data
PublicationCoastal zones are not only the fundaments for local economics based on trade, shipping and transport services, but also a source of food, energy and resources. Apart from offering diverse opportunities for recreation and tourism, coastal zones provide protection against storms and other meteorological disturbances. Environmental information is also essential because of the direct influence on a country’s maritime zones, which are...
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Cyanogenic Compounds and Estrogen Disruptors
PublicationBalanced diet consists largely of plants containing cyanogenic compounds in the form of the more common cyanogenic glycosides and sometimes lipids. Maize, wheat, rye, apples, barley, oats, sugar cane and yet many other plants consumed by humans contain cyanogenic compounds. However the risk of poisoning is negligible as it is very easy to remove the toxic HCN by grinding and drying in air or soaking in water and an additional...
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CAUSALITY IN MODELS OF THERMAL PROCESSES IN SHIP ENGINE ROOMS WITH THE USE OF BOND GRAPH (BG) METHOD
PublicationWith a single approach to modeling elements of different physical nature, the method of Bond Graph (BG) is particularly well suited for modeling energy systems consisting of mechanical, thermal, electrical and hydraulic elements that operate in the power system engine room. The paper refers to the earlier presented new concept of thermal process modeling using the BG method. The authors own suggestions for determining causality...
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Harnessing digital technologies for poverty reduction. Evidence for low-income and lower-middle income countries
PublicationThis paper contributes to understanding the relationship between ICT deployment and poverty alleviation in developing countries. It assess the digital technologies contribution to poverty reduction, through different channels of impact, like education, labor market, income and ICTtrade related activities. Using the sample of 40 developing countries between 1990 and 2019, it relies on macro data extracted from the World Bank Development...
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Quality Control of Bacterial Extracellular Vesicles with Total Protein Content Assay, Nanoparticles Tracking Analysis, and Capillary Electrophoresis
PublicationExtracellular vesicles (EVs) were isolated from Pectobacterium zantedeschiae culturing media using direct ultracentrifugation (UC), iodixanol cushion ultracentrifugation (ICUC), and iodixanol density gradient ultracentrifugation (IDGUC) techniques. The isolates were characterized with total protein content assay (bicinchoninic acid assay, BCA), nanoparticles tracking analysis (NTA), and capillary electrophoresis (CE). A satisfactory...
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Accelerated large scale test set-up design in natural corrosion marine environment
PublicationThe standards for conducting small-scale specimen tests are well developed, but there is a lack of direct guidelines for conducting corrosion tests for large-scale specimens. The objective here is to develop a methodology which may be used in designing an accelerated corrosion test of large-scale structural components subjected to a natural corrosion marine environment. Different factors influencing corrosion degradation of steel...
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Smart Specializations as Innovative Ecosystems
PublicationIn the article it is showed that regional smart specializations that are currently the most important tool of the European innovation policy may be perceived, and if effective should constitute, innovative ecosystems. The article presents the concepts of smart specializations and innovative ecosystems. The concept of innovative ecosystem is, in the article, presented from the perspective of its foundation and relations to other...
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Risks associated with the transportation of hazardous materials on public roads
PublicationA significant proportion of the transport of hazardous materials is carried out on public roads. Therefore, the safety of such transport is becoming increasingly important. Every catastrophe involving hazardous materials has a negative impact on direct road users and the surrounding environment, becauses its range is mostly not local. It follows that in the event of such catastrophe, its effects should be minimized. This is possible...
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The effects of perceived risk, brand value, and brand trust on eWOM
PublicationUnrestricted access to the Internet, mobile devices, social applications and offering shopping comment options via online stores and platforms, encourages customers to generate online reviews about brands. That is why it became important to learn about the factors that motivate customers to create electronic word of mouth (eWOM). The survey aimed to check if there are links between perceived brand value, perceived risk, brand trust...
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Widespread theta synchrony and high-frequency desynchronization underlies enhanced cognition
PublicationThe idea that synchronous neural activity underlies cognition has driven an extensive body of research in human and animal neuroscience. Yet, insufficient data on intracranial electrical connectivity has precluded a direct test of this hypothesis in a whole-brain setting. Through the lens of memory encoding and retrieval processes, we construct whole-brain connectivity maps of fast gamma (30-100 Hz) and slow theta (3-8 Hz) spectral...
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Refined theoretical study of radiative association: Cross sections and rate constants for the formation of SiN
PublicationRadiative association of silicon mononitride (SiN) in its two lowest molecular electronic states is studied through quantum and classical dynamics. Special attention is paid to the behavior of the cross section at high collision energies. A modified expression for the semiclassical cross section is presented which excludes transitions to continuum states. This gives improved agreement with quantum mechanical perturbation theory...
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Storing Matter’technique in SIMS depth profile analysis
PublicationSecondary ion mass spectrometry (SIMS) is a very useful technique for the analysis of layered systems. It is based on the primary ion beam sputtering of solids and mass analysis of the emitted secondary ions. A main limitation of this technique results from the direct quantitative analysis, since the ionization efficiency of a given atom is highly influenced by the neighbouring atoms at the surface. This phenomenon is known as...
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Optical and photoelectrochemical characterization of pulsed laser deposited Bi4V2O11, BICUVOX, and BIZNVOX
PublicationThin layers of three compounds from the BIMEVOX family (Bi4V2O11, Bi2V0.9Cu0.1O5.35, and Bi2V0.9Zn0.1O5.35) were prepared via pulsed laser deposition technique on quartz, silicon, and platinum foil and tested as photoanodes for water photooxidation. The film formation, as well as the crystallization upon heating, was characterized using X-ray diffraction and Raman spectroscopy. The optical properties were investigated using spectroscopic...
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Cu supported on various oxides as a candidate catalyst for dry methane reforming in DIR-SOFCs systems
PublicationA series of Cu-support systems were tested as potential candidates for DIR-SOFC (Direct Internal Reforming SOFC) catalysts towards a dry reforming of methane (DRM). The various supports (-Al2O3, CeO2, ZrO2, SrTiO3) with comparable specific surface area (SSA), and additionally -Al2O3 with SSA an order of magnitude larger than that of the other supports has been applied. The obtained Cu-support systems were characterized in terms...
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THE ESSENCE OF THE TRANSFORMATION OF SOCIO-ECONOMIC RELATIONS IN THE NATIONAL ECONOMY: THEORETICAL AND METHODOLOGICAL ASPECT
PublicationThe article is devoted to a thorough study of the theoretical and methodological foundations of the essence of the transformation of socio-economic relations of the national economy. Based on the study of scientific sources, a proper definition of the concept of "transformation of socio-economic relations" was formed. It is proposed to consider transformational processes from the point of view of their direct or indirect impact...
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Brownian Motion in Optical Tweezers, a Comparison between MD Simulations and Experimental Data in the Ballistic Regime
PublicationThe four most popular water models in molecular dynamics were studied in large-scale simulations of Brownian motion of colloidal particles in optical tweezers and then compared with experimental measurements in the same time scale. We present the most direct comparison of colloidal polystyrene particle diffusion in molecular dynamics simulations and experimental data on the same time scales in the ballistic regime. The four most...
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Biological and antibacterial properties of chitosan-based coatings with AgNPs and CuNPs obtained on oxidized Ti13Zr13Nb titanium alloy
PublicationDespite numerous studies, the antibacterial efficiency and cytotoxicity of chitosan-based coatings with nanometals need further studies. The purpose of this research was to determine the biological properties of chitosan coatings implemented with either silver nanoparticles (AgNPs) or copper nanoparticles (CuNPs), that were electrophoretically deposited on electrochemically oxidized Ti13Zr13Nb alloy. The SEM tests were used to...
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Isolation and structure of a covalent cross-link adduct between mitomycin C and DNA
PublicationA DNA cross-link adduct of the antitumor agent mitomycin C (MC) to DNA has been isolated and characterized; the results provide direct proof for bifunctional alkylation of DNA by MC. Exposure of MC to Micrococcus luteus DNA under reductive conditions and subsequent nuclease digestion yielded adducts formed between MC and deoxyguanosine residues. In addition to the two known monoadducts, a bisadduct was obtained. Reductive MC activation...
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Selected concentration techniques for gas chromatographic analysis of environmental samples
PublicationThe paper describes the role and tasks of environmental analysis and monitoring. It emphasises the leading role played by gas chromatography, especially when coupled with suitable sample preparation. This is demonstrated by some literature evidence and mainly by the author's original work on the design of sample preparation apparatus and development of GC-based methods of determination of a wide variety of organic pollutants in...
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Research of electric drive systems with real time software configurable control
PublicationПредмет исследования. Представлен учебно-лабораторный стенд для исследования систем управления элек- троприводами. Стенд используется для обучения студентов системам управления электроприводами и предна- значен для повышения эффективности усвоения материала. Метод. В основу предлагаемого решения положен метод взаимного нагружения электрических машин, питаемых от силовых преобразователей с общим звеном постоянного тока. Это позволяет...
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Charge Distribution and Hyperfine Interactions in GdBa2Cu3O7 from First Principles
PublicationW rozdziale przedstawiono wyniki obliczeń "z zasad pierwszych" (''ab initio'') struktury elektronowej, rozkładu ładunku i struktury nadsubtelnej, w szczególności gradientu pola elektrycznego (EFG) i składnika kontaktowego pola nadsubtelnego (HFF), nadprzewodnika wysokotemperaturowego o wzorze GdBa2Cu3O7 (Gd123). Do obliczeń wykorzystano metodę FP-LAPW (full-potential linearized augmented plane wave). Efekty związane z oddziaływaniami...
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Electron collisions with methyl-substituted ethylenes: Cross section measurements and calculations for 2-methyl–2-butene and 2,3-dimethyl–2-butene
PublicationWe report electron-scattering cross sections determined for 2-methyl–2-butene [(H3C)HC==C(CH3)2] and 2,3-dimethyl–2-butene [(H3C)2C=C(CH3)2] molecules. Absolute grand-total cross sections (TCSs) were measured for incident electron energies in the 0.5–300 eV range, using a linear electron-transmission technique. The experimental TCS energy dependences for the both targets appear to be very similar with respect to the shape. In each...
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Customer Assessment of Brand Valuation and Social Media
PublicationThe research problem engaged in this article is to determine whether contemporary consumers are able to assess brand equity in the overabundance of brands and products with similar features and qualities. The author argues that in the existing circumstances when differences between brands become insignificant the consumer is not capable of assessing their equity adequately. In order to verify the thesis the author has accepted...
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Modeling of medium flow processes in transportation pipelines - the synthesis of their state-space models and the analysis of the mathematical properties of the models for leak detection purposes
PublicationThe dissertation concerns the issue of modeling the pipeline flow process under incompressible and isothermal conditions, with a target application to the leak detection and isolation systems. First, an introduction to the model-based process diagnostics is provided, where its basic terminology, tools, and methods are described. In the following chapter, a review of the state of the art in the field of leak detection and isolation...
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Design-oriented modeling of antenna structures by means of two-level kriging with explicit dimensionality reduction
PublicationThe employment of full-wave electromagnetic (EM) analysis is a practical necessity in the design of contemporary antenna structures. This is because simpler models are generally not available or of limited accuracy. At the same time, EM-based design is computationally expensive. Consequently, the ways of accelerating tasks such as parametric optimization or uncertainty quantification have to be sought. A possible workaround that...
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Low-Cost Modeling of Microwave Components by Means of Two-Stage Inverse/Forward Surrogates and Domain Confinement
PublicationFull-wave electromagnetic (EM) analysis is one of the most important tools in the design of modern microwave components and systems. EM simulation permits reliable evaluation of circuits at the presence of cross-coupling effects or substrate anisotropy, as well as for accounting for interactions with the immediate environment. However, repetitive analyses required by EM-driven procedures, such as parametric optimization or statistical...
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Social convergence in Nordic countries at regional level
PublicationResearch background: Geographical proximity, common historical roots and collaboration within the Nordic Council cause the Nordic countries to be often wrongly treated as monoliths. However, in reality, Nordic regions differ in terms of broadly defined social and economic development. Issues concerning the standard of living are one of the priorities of the Helsinki Treaty signed by Nordic countries. Purpose of the article: The...
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Design-Oriented Two-Stage Surrogate Modeling of Miniaturized Microstrip Circuits with Dimensionality Reduction
PublicationContemporary microwave design heavily relies on full-wave electromagnetic (EM) simulation tools. This is especially the case for miniaturized devices where EM cross-coupling effects cannot be adequately accounted for using equivalent network models. Unfortunately, EM analysis incurs considerable computational expenses, which becomes a bottleneck whenever multiple evaluations are required. Common simulation-based design tasks include...
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Thermal-Resistant Polyurethane/Nanoclay Powder Coatings: Degradation Kinetics Study
PublicationIn the present study, thermal degradation kinetics of polyurethane (PU) powder coatings reinforced with organo-modified montmorillonite (OMMT) was investigated. PU nanocomposites were prepared in different concentrations of 1, 3, and 5 wt.% of OMMT via the extrusion method. The microstructure of the nanocomposites was observed by scanning electron microscope (SEM) illustrating uniform dispersion of OMMT nano-clay platelets in the...
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Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)2Pt(CN)4] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks
PublicationParamount spin-crossover properties of the 3D-Hoffman metalorganic framework (MOF) [Fe(pz)2Pt(CN)4] are generally described on the basis of the ligand field theory, which provides adequate insight into theoretical and simulation analysis of spintronic complexes. However, the ligand field approximation does not take into account the 3D periodicity of the actual complex lattice and surface effects and therefore cannot predict a full-scale...
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Optimization of the Hardware Layer for IoT Systems using a Trust Region Method with Adaptive Forward Finite Differences
PublicationTrust-region (TR) algorithms represent a popular class of local optimization methods. Owing to straightforward setup and low computational cost, TR routines based on linear models determined using forward finite differences (FD) are often utilized for performance tuning of microwave and antenna components incorporated within the Internet of Things systems. Despite usefulness for design of complex structures, performance of TR methods...
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Computational analysis of power-law fluids for convective heat transfer in permeable enclosures using Darcy effects
PublicationNatural convection is a complex environmental phenomenon that typically occurs in engineering settings in porous structures. Shear thinning or shear thickening fuids are characteristics of power-law fuids, which are non-Newtonian in nature and fnd wide-ranging uses in various industrial processes. Non-Newtonian fuid fow in porous media is a difcult problem with important consequences for energy systems and heat transfer. In this...
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Synteza układu sterowania statkiem morskim dynamicznie pozycjonowanym w warunkach niepewności
PublicationNiniejsza monografia obejmuje zagadnienia związane z syntezą układu dynamicznego pozycjonowania statku w środowisku morskim z zastosowaniem wybranych nieliniowych metod sterowania. W ramach pracy autorka rozważała struktury sterowania z zastosowaniem wektorowej adaptacyjnej metody backstep oraz metod jej pokrewnych, takich jak regulatory MSS (ang. multiple surface sliding), DSC (ang. dynamic surface control), NB (ang. neural backstepping)....
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Pomiar ryzyka bankowego - propozycja typologii
PublicationW artykule zaproponowano typologię pomiaru ryzyk bankowych. Wyodrębnione kryteria podziału podejść do pomiaru ryzyka to: (1) pomiar bezpośredni/pośredni, (2) pomiar ex post/ex ante, (3) kryterium oparte o składnik ryzyka – częstotliwość, dotkliwość, ekspozycja, całościowa strata, (4) kryterium oparte o parametr rozkładu: pomiar wartości oczekiwanej/przeciętnej, pomiar rozproszenia, pomiar wartości skrajnych. Wśród motywów pomiaru...
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Peptydy penetrujące – rodzaje i mechanizmy przenikania przez błony komórkowe
PublicationPeptydy penetrujące z pewnością są wyjątkową i ciekawą grupą związków peptydowych. Zostały odkryte ponad dwadzieścia lat temu, ale wiedza na ich temat wciąż jest rozbudowywana. Liczne badania nad mechanizmami ich przenikania do wnętrza komórek pozwalają zrozumieć jakie cechy strukturalne warunkują ich zdolność do penetracji komórek. Wiedza ta pozwala na projektowanie nowych, bardziej efektywnych peptydów penetrujących., które mogą...
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Koncepcja analizy stanów emocjonalnych użytkowników w kontekście systemów zabezpieczeń transportowych
PublicationAutorzy, przywołując własne i światowe badania nad rozpoznawaniem emocji ludzkich z obrazu twarzy, wskazują na możliwość zastosowania algorytmów komputerowych i ich implementacji w komputerach osobistych (i innych urządzeniach personalnych wyposażonych w dostatecznie silny procesor obliczeniowy). Zastosowanie takiego rozwiązania może poprawić bezpieczeństwo użytkowania urządzeń, maszyn i pojazdów, których operatorzy muszą gwarantować...
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WYKORZYSTANIE TESTU MUSHRA W BADANIU KORZYŚCI UŻYTKOWANIA PROTEZ SŁUCHOWYCH
PublicationOcena jakości dopasowania aparatów słuchowych w kontekście korzyści, jakie może przy-nieść proteza jest złożonym zagadnieniem. Obiektywne parametry aparatów, które można wy-znaczyć (np. wzmocnienie czy pasmo przenoszenia) nie zawsze mają bezpośredni i decydujący wpływ w subiektywnej ocenie jakości dopasowania protezy słuchowej przez pacjenta. Pomiary efektywności aparatu słuchowego mogą dotyczyć wielu aspektów, między innymi kompensacji...