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Discrete Green's function approach to disjoint domain simulations in 3D FDTD method
PublicationA discrete Green’s function (DGF) approach to couple 3D FDTD subdomains is developed. The total-field/scattered-field subdomains are simulated using the explicit FDTD method whilst interaction between them is computed as a convolution of the DGF with equivalent current sources measured over Huygens surfaces. In the developed method, the DGF waveforms are truncated using the Hann’s window. The error varies in the range -65 to -40...
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Microstructure and residual stresses in surface coatings with PTFE reservoirs
PublicationThe paper presents the results of experimental study into the microstructure and changes in residual stresses resulting from sliding and rolling/sliding loaded interaction between metallic surface coatings with embedded PTFE reservoirs and various counter faces. It was found that before testing surface coatings had compressive residual stresses. Molybdenum coating with all types of PTFE reservoirs displayed, as a result of testing,...
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Tribological performance of PTFE-metal binary coatings in rolling/sliding contact
PublicationTribological performance of surface coatings with embedded PTFE reservoirs in rolling/sliding contact is reported. Using two different coating materials and two shapes and patterns of PTFE reservoirs test samples in the form of discs were prepared and tested in a four-ball contact configuration under loads corresponding to nominal contact pressure of 0.5 and 1.0 GPa. It was found that one coating, namely aluminium-bronze with embedded...
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Performance of lubricated sliding contact in magnetic field
PublicationResults of experimental studies concerning theinfluence of permanent magnetic field on wear of lubricatedsliding contact operating at short stroke and highfrequency are presented. It was found that horizontalmagnetic is affecting performance of the contact. Thejagged delamination regions produced in the presence of amagnetic field can be regarded as easily undergoing oxidisationbecause oxygen is readily adsorbed there. Magneticfield...
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Tautomerism, structure and properties of 1,1',1''-(2,4,6-trihydroxybenzene-1,3,5-triyl)triethanone
PublicationWedług teoretycznych przewidywań 1,3,5-triacetylo-2,4,6-trihydroksybenzen może występować w 5 formach tautomerycznych, z których dwie powinny wyróżniać się wysoką stabilnością. Teoretyczne przewidywania zostały skonfrontowane z rezultatami pomiarów spektralnych.
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Helicity Discrimination in Diaryl Dichalcogenides Generateded by Inclusion Complexation with Chiral Hosts
PublicationNiektóre z molekuł pozbawione centrum stereogenicznego mogą przyjmować chiralną konformację na skutek wewnętrznej rotacji wzdłuż odpowiedniego wiązania. Do grupy tej należą badane przez nas diarylodichalogenki; diarylodisiarczki, diarylodiselenki i diaryloditellurki. Niska bariera rotacji wokół wiązania chalogen-chalogen skutkuje szybką racemizacją molekuł tych związków w roztworze i uniemożliwia badanie czynności optycznej. Wykazaliśmy,...
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A study on the protection of methionine and the reduction of methionine sulfoxide in methionine-containing analogues of the growth-modeling factor Gly-His-Lys
PublicationThe protection of methionine and the reduction of methionine sulfoxide in methionine-containing analogues of Gly-His-Lys are described. The peptides were synthesized by a solid-phase method using the standard Fmoc procedure. Simultaneous deprotection of the peptide side chain and liberation from the resin were achieved using an appropriate TFA cocktail. The TFA cocktail was selected to minimize oxidation of the methionine residue....
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Quantum corections to SG equation solutions and applications
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Electrochemicalsynthesis of 3D nano-/micro-structured porous polypyrrole
PublicationIn this work, electrosynthesis of electroactive, 3D nano-/micro-structured porous polypyrrole film is presented. The PPy film was synthesized potentiostatically in a one-step process from aqueous solution of pyrrole and lithium perchlorate. The growth mechanism of such structure included: the formation of typical globular PPy film, followed by the formation of the PPy fibers, which then took part in the formation of 3D highly porous...
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Influence of Humidity on Parameters of Amperometric Sensor with Nafion Membrane
PublicationPrzedstawiono wyniki badań wpływu umiarkowanych i wysokich wilgotności powietrza na sygnał, czułość i czas odpowiedzi prototypowego czujnika ditlenku siarki ze złotą elektrodą pracującą, próżniowo napyloną na powierzchnię membrany nafionowej. Zaprezentowano także wyniki badań impedancyjnych w zakresie potencjałów, w którym mechanizm utleniania ditlenku siarki jest kontrolowany aktywacyjnie i dyfuzyjnie. Parametry odpowiadające...
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Teaching of Analytical Chemistry in Polisch Universities
PublicationChemia Analityczna zajmuje się poszukiwaniem i opracowywaniem optymalnych strategii (metod i urządzeń) pozwalających na uzyskiwanie miarodajnych informacji dotyczących chemicznej natury różnych obiektów znajdujących się w naszym otoczeniu i przebiegających w nich procesach. Wykorzystanie informacji analitycznej jest bardzo szerokie. Otrzymany wynik jest towarem, tym droższym im jest bardziej miarodajny. Chemik analityk odpowiada...
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Nuclear Activation Methods in the Estimation of Environmental Pollution and the Assessment of the Industrial Plant Impact on the Citizens of Gdansk (Poland)
PublicationNeutronowa Analiza Aktywacyjna została wykorzystana do oceny stanu jakości powietrza atmosferycznego na podstawie badań analitycznych stopnia kumulacji zanieczyszczeń nieorganicznych w mchu torfowca, a także składu wód opadowych. Ponadto przedstawiono wyniki badań dotyczących szacowania ryzyka zawodowego pracowników zakładów przemysłowych na podstawie analizy próbek materiału biologicznego pobranego od osób narażonych.
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Comparison of different extraction techniques of polychlorinated biphenyls from sediments samples.
PublicationIn this work, problems that may occur during determination of trace levels of polychlorinated biphenyls in sediment samples are described. Main error sources are connected with extraction of analytes prior to final determination. During model studies, polychlorinated biphenyls have been extracted from sedimentreference material (METRANAL 2) with the use of different solvents (dichloromethane, hexsane, and toluene); the process...
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Analytical Study of Sliding Instability due to Velocity- and Temperature-Dependent Friction
PublicationThe instability of sliding causes deterioration of performance characteristics of tribosystems and is undesired. To predict its occurrence, the motion of a body of a one-degree-of-freedom system with friction is investigated about the steady sliding equilibrium position. The motion equation is formulated with the friction coefficient dependent on the sliding velocity and contact temperature changing due to transient heat conduction...
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Chitosan/poly(4-vinylpyridine) coatings formed on AgNPs-decorated titanium
PublicationElectrophoretic deposition (EPD) of chitosan/poly(4-vinylpyridine) (chit/P4VP) coatings on titanium substrates previously decorated with silver nanoparticles (AgNPs) was performed at different content of P4VP in the suspension and different voltage values. The results revealed that the composite coatings were formed, well-adjacent to the titanium substrate, of suitable roughness, hydrophilicity, and corrosion resistance. The voltage...
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Morphology of damage inflicted on brittle polymer in lubricated contact under cyclic static load
PublicationIn this article morphology of damage inflicted on the polymethylmethacrylate (PMMA) plate in static point lubricated contact with a ball made of five different materials under cyclic normal load has been presented. It is argued that the counterface material and lubricating film play an important role in the damage process and the extent of damage inflicted in the PMMA plate.
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Ultrasound assisted synthesis of 3-alkynyl substituted 2-chloroquinoxaline derivatives: Their in silico assessment as potential ligands for N-protein of SARS-CoV-2
PublicationIn view of recent global pandemic the 3-alkynyl substituted 2-chloroquinoxaline framework has been explored as a potential template for the design of molecules targeting COVID-19. Initial in silico studies of representative compounds to assess their binding affinities via docking into the N-terminal RNA-binding domain (NTD) of N-protein of SARS-CoV-2 prompted further study of these molecules. Thus building of a small library of...
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Compact 4 × 4 butler matrix with non‐standard phase differences for IoT applications
PublicationButler matrices represent a popular class of feeding networks for antenna arrays. Large dimensions and the lack of flexibility in terms of achievable output phase difference make conventional Butler structures of limited use for modern communication devices. In this work, a compact planar 4 × 4 matrix with non-standard relative phase shifts of –30º, 150º, –120º, and 60º has been proposed. The structure is designed to operate at...
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Extended duration running and impulse loading characteristics of an acoustic bearing with enhanced geometry
PublicationThis paper presents performance during prolonged running of the acoustic bearing when PZTs are switched off and when they are switched on. The effect of active PZT on shaft’s displacements in X and Y directions is clearly demonstrated. Performance of the acoustic bearing was also assessed when an impulse force was applied to the running shaft at speed. Once again the benefits of having PZTs active are beyond doubt. The instability...
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Ab Initio Study of the Electronic Spectrum of 7-Hydroxyquinoline
PublicationThe electronic spectrum of 7-hydroxyquinoline has been studied by using ab initio Multi-State Multi-Reference Møller-Plesset Second-Order Perturbation Theory (MSMRMP2). The energy range up to 6.5 eV is taken into consideration. The lowest π–π* transition is calculated to have an energy of 3.65 eV in good agreement with experimental data. Several other π–π* transitions are predicted to have excitation energies of 4.93, 5.20, 5.47,...
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Effect of interconnect coating procedure on solid oxide fuel cell performance
PublicationChromium (Cr) species vaporizing from chromia-forming alloy interconnects is known as a source of degradation in solid oxide fuel cell (SOFC) stacks called “cathode poisoning”. (Mn,Co)3O4 spinel coatings offer good protection against Cr evaporation during operation. In this study, Crofer 22 APU steel interconnects were electrophoretically deposited in different mediums to obtain high packing of green coating layer. The optimized...
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Electrical conductivity of nanostructured acceptor-doped ceria fabricated by spark plasma sintering (SPS)
PublicationHigh purity nanoscale powders (~10–15 nm size) of two different compositions of ceria, doped with Gd3+ and Ca2+, have been consolidated by spark plasma sintering (SPS) at different temperatures. Fully-dense samples were observed only at a sintering temperature of 980 °C. The as-sintered samples showed rather fast grain growth with an average grain size below 300 nm. The electrical properties of the samples were evaluated by impedance...
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Recent advances on spinel-based protective coatings for solid oxide cell metallic interconnects produced by electrophoretic deposition
PublicationThe application of ceramic protective coatings to the metallic interconnects in solid oxide cells (SOCs) is a viable and effective method to limit interconnect degradation issues. This featured letter provides a critical overview of the main outcomes of current research on the use of the electrophoretic deposition (EPD) technique to produce protective coatings for SOC metallic interconnects, specifically focusing on different approaches...
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Biological properties of chitosan/Eudragit E 100 and chitosan/poly(4-vinylpyridine) coatings electrophoretically deposited on AgNPs-decorated titanium substrate
PublicationThe objective of the study was the determination of the response, in contact with human osteoblast-like MG-63 cells, of electrophoretically deposited coatings composed of chitosan (CS), Eudragit E 100 (EE100), or poly(4- vinylpyridine) (P4VP) on a silver nanoparticle (AgNPs)-decorated titanium substrate. Before deposition, the substrate was coated with silver by electro-reduction of silver nitrate. The coatings deposition was carried...
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InGaN trapered laser diodes
PublicationW pracy zaprezentowano rezultaty badan nad diodami laserowymi InGaN ze zwężającym się kanałem. Kąty kanałów zmieniane były w zakresie 2 -5 stopni, jak również zmieniana była długość kanału. Wykazano, że w przypadku optymalnych parametrów, parametr M2 (M kwadrat) opisujący odtępstwa wiązki od krzywej Gaussa, wynosił 2.1 przy mocy optycznej 200 mW.
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Dual-band antenna with improved gain for WLAN and ISM applications
PublicationIn this Letter, a dual-band antenna with an improved gain is proposed. The structure features 9.7 and 10.4 dBi gain within 2.4 GHz to 2.5 GHz and 5 GHz to 6 GHz bands, respectively. This makes it suitable for WLAN and ISM applications. The structure comprises an asymmetrical pair of radiators and slots suspended over a reflector. The antenna is optimised in a two-stage process using a trust-region-based gradient search algorithm....
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Time travel without paradoxes: Ring resonator as a universal paradigm for looped quantum evolutions
PublicationA ring resonator involves a scattering process where a part of the output is fed again into the input. The same formal structure is encountered in the problem of time travel in a neighborhood of a closed timelike curve (CTC). We know how to describe quantum optics of ring resonators, and the resulting description agrees with experiment. We can apply the same formal strategy to any looped quantum evolution, in particular to the...
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Enhanced photocatalytic activity of transparent carbon nanowall/TiO2 heterostructures
PublicationThe synthesis of novel tunable carbon-based nanostructure represented a pivotal point to enhance the efficiency of existing photocatalysts and to extend their applicability to a wider number of sustainable processes. In this letter, we describe a transparent photocatalytic heterostructure by growing boron-doped carbon nanowalls (B-CNWs) on quartz, followed by a simple TiO2 sol-gel deposition. The effect on the thickness and boron-doping...
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States of light via reducible quantization.
PublicationRelatywistyczne sformułowanie kwantowania pola opartego o redukowalne reprezentacje kanonicznych związków komutacyjnych. Konstrukcja stanów fokowskich i koherentnych. Analiza automatycznej regularyzacji rozbieżności w podczerwieni. Twierdzenie o granicy termodynamicznej.
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Simultaneous detrmination of selected phenoxyacid herbicides and chlorophenols in surface and seawater by HPLC coupled to DAD.
PublicationDo badań wykorzystano metodę ekstrakcji do fazy stałej (SPE) w celu wzbogacenia analitów. Ekstrakty analizowano techniką wysokosprawnej chromatografii cieczowej (HPLC) z detekcją DAD. Opracowana metoda umożliwia oznaczenie 14 związków z grupy kwasów fenoksyoctowych i chlorofenoli w czasie 22 min. Odzysk analitów wynosił powyżej 60% dla fenoksykwasów i powyżej 70% w przypadku chlorofenoli. Granica oznaczalności dla oznaczania...
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Direct estimation of elements of algebra of quantum states and entanglement detection via linear contraction.
PublicationWykazano możliwość obliczenia elementów algebry generowanej przez macierze bez uprzedniej rekonstrukcji stanu. Ponadto wykazano, że pewne testy separowalności oparte o liniowe operacje zwężające można przeprowadzić bez uprzedniej rekonstrukcji badanych stanów.
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Piecewise continuous distribution function method in the theory of wave disturbances of inhomogeneous gas
PublicationUkład równań typu hydrodynamicznego dla warstwowych gazów w polu grawitacyjnym pochodzi od równania BGK metodą częściowej ciągłej funkcji dystrybucji. Otrzymany system równań uogólnia układ Naviera-Stokesa w dowolnych liczbach Knudsena.
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Sources of errors associated with the determination of PAH and PCB analytes in water samples
PublicationW pracy przedstawiono problemy związane z oznaczaniem analitów z grupy WWA i PCB w próbkach wody. Zidentyfikowano źródła błędów. Szczególną uwagę zwrócono na:- proces adsorpcji analitów na ściankach szklanych naczyń używanych w trakcie obróbki i przechowywania próbek,- wpływ etapu odparowywania nadmiaru rozpuszczalnika z ekstraktów na odzysk analitów,- wpływ materiału, z którego jest wykonana kolumienka ekstrakcyjna (szkła, polietylenu)...
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Estimation of zero buoyancy of the batyscaphe. Pneumatic buoyancy control of the bathyscaphe
PublicationThe subjects of this work are matters concerning the batyscaphe designed and constructed by the Scientific Circle of Young Constructors (SCoYC) acting at the Faculty of Technical Sciences of the Olsztyn University of Warmia and Mazury.The goal od the remote-controlled batyscaphe is an underwater exploration of water resorvoirs in Poland. Design and construction of the unmanned watercraft, also known as a batyscaphe, required the...
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Zaufanie w zespole projektowym a (kobiecy) model przywództwa
PublicationArtykuł prezentuje wyniki badań dotyczące znaczenia czynników kształtujących zaufanie w pracy zespołowej, do których należą: adekwatne nagradzanie, dzielenie się informacjami, ustalone cele i zasady pracy, przejrzystość środowiska i otwarta komunikacja. Wyniki koncentrują się na zachowaniach lidera/ przywódcy, które maja wpływ na kształtowanie zaufanie w zespole i pokazują różnice w zależności od płci.
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Lossless Compression of Binary Trees with Correlated Vertex Names
PublicationCompression schemes for advanced data structures have become the challenge of today. Information theory has traditionally dealt with conventional data such as text, image, or video. In contrast, most data available today is multitype and context-dependent. To meet this challenge, we have recently initiated a systematic study of advanced data structures such as unlabeled graphs [1]. In this paper, we continue this program by considering...
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Is Digital Government Advancing Sustainable Governance? A Study of OECD/EU Countries
PublicationInternational bodies and numerous authors advocate a key role for Digital Government (DG) in improving public governance and achieving other policy outcomes. Today, a particularly relevant outcome is advancing Sustainable Governance (SG), i.e., the capacity to steer and coordinate public action towards sustainable development. This article performs an empirical study of the relationship between DG and SG using data about 41 OECD/EU...
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User -friendly E-learning Platform: a Case Study of a Design Thinking Approach Use
PublicationE-learning systems are very popular means to support the teaching process today. These systems are mainly used by universities as well as by commercial training centres. We analysed several popular e-learning platforms used in Polish universities and find them very unfriendly for the users. For this reason, the authors began the work on the creation of a new system that would be not only useful, but also usable for students, teachers...
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Cost-efficient design optimization of compact patch antennas with improved bandwidth
PublicationIn this letter, a surrogate-assisted optimization procedure for fast design of compact patch antennas with enhanced bandwidth is presented. The procedure aims at addressing a fundamental challenge of the design of antenna structures with complex topologies, which is simultaneous adjustment of numerous geometry parameters. The latter is necessary in order to find a truly optimum design and cannot be executed-at the level of high-fidelity...
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Effect of pH on optical sensing with poly-L-lysine-modified nanodiamonds
PublicationNitrogen-vacancy (NV) centers are crystallographic defects which provide diamonds with unique physical properties. The centers are known for their intensive, time-stable fluorescence, and an electron spin, which exhibits long coherence time and may be manipulated using external stimuli. Nanodiamonds containing the NV centers are promising tools in biolabeling, biosensing, and drug delivery due to the aforementioned properties of...
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Infrared techniques for natural convection investigations in channels between two vertical, parallel, isothermal and symmetrically heated plates
PublicationThe effect of the gap width between two symmetrically heated vertical, parallel, isothermal plates on intensity of natural convective heat transfer in a gas (Pr = 0.71) was experimentally studied using the balance and gradient methods. In the former method heat fluxes were determined based on measurements of the voltage and electric current supplying the heaters placed inside the walls. In the latter, heat fluxes were calculated...
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Anticancer Properties of Amino Acid and Peptide Derivatives of Mycophenolic Acid
PublicationBackground: Although Mycophenolic Acid (MPA) is applied as prodrugs in clinic as an immunosuppressant, it also possesses anticancer activity. MPA acts as Inosine-5’-Monophosphate Dehydrogenase (IMPDH) inhibitor, where the carboxylic group at the end of the side chain interacts with Ser 276 of the enzyme via hydrogen bonds. Therefore, MPA derivatives with other polar groups indicated high inhibition too. On the other hand, potent...
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The Design Development of the Sliding Table Saw Towards Improving Its Dynamic Properties
PublicationCutting wood with circular saws is a popular machining operation in the woodworking and furniture industries. In the latter sliding table saws (panel saws) are commonly used for cutting of medium density fiberboards (MDF), high density fiberboards (HDF), laminate veneer lumber (LVL), plywood and chipboards of different structures. The most demanded requirements for machine tools are accuracy and precision, which mainly depend on...
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Automated Reduced Model Order Selection
PublicationThis letter proposes to automate generation of reduced-order models used for accelerated -parameter computation by applying a posteriori model error estimators. So far,a posteriori error estimators were used in Reduced Basis Method (RBM) and Proper Orthogonal Decomposition (POD) to select frequency points at which basis vectors are generated. This letter shows how a posteriori error estimators can be applied to automatically select...
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Synthesis of coupled lossy resonator filters.
PublicationA technique for fast synthesis of coupling matrix low-pass prototypes of generalized. Chebyshev bandpass filters with lossy resonators is presented in this letter. The coupling matrix is found by solving a nonlinear least squares problem based on zeros and poles of filter's transfer functions.
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ARIMA vs LSTM on NASDAQ stock exchange data
PublicationThis study compares the results of two completely different models: statistical one (ARIMA) and deep learning one (LSTM) based on a chosen set of NASDAQ data. Both models are used to predict daily or monthly average prices of chosen companies listed on the NASDAQ stock exchange. Research shows which model performs better in terms of the chosen input data, parameters and number of features. The chosen models were compared using...
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Auto-tuning methodology for configuration and application parameters of hybrid CPU + GPU parallel systems based on expert knowledge
PublicationAuto-tuning of configuration and application param- eters allows to achieve significant performance gains in many contemporary compute-intensive applications. Feasible search spaces of parameters tend to become too big to allow for exhaustive search in the auto-tuning process. Expert knowledge about the utilized computing systems becomes useful to prune the search space and new methodologies are needed in the face of emerging heterogeneous...
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Możliwości zamiany elektrycznych przepływomierzy powietrza stosowanych w silnikach spalinowych samochodów
PublicationW artykule przedstawiono podstawowe typy przepływomierzy powietrza, stosowane w silnikach spalinowych samochodów: z klapąspiętrzającą, HLM, HFM, Vortex i MAP. Przedstawiono wyniki badania tych przepływomierzy na specjalnie przygotowanym stanowisku pomiarowym. Przeanalizowano możliwość ich zamiany i zweryfikowano taką możliwość w praktyce.
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ZARZADZANIE ORGANIZACJĄ TYPU SMART
PublicationZaprezentowano organizacji, w której charakterystykę wpisano następujące cechy: strategiczne uwarunkowanie, maksymalną innowacyjność, atrakcyjność dla interesariuszy, rozwijanie osobowości pracowników oraz twórczość w działaniu. Te atrybuty, tworzą koncepcję organizacji SMART (akronim od pierwszych liter powyższych cech), która wyróżnia się dodatkowo strukturą opartą o dynamicznie kreowane zespoły oraz skutecznym wspomaganiem...
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Magnetically sensitive fiber probe with nitrogen-vacancy center nanodiamonds integrated in a suspended core
PublicationEfficient collection of photoluminescence arising from spin dynamics of nitrogen vacancy (NV) centers in diamond is important for practical applications involving precise magnetic field or temperature mapping. These goals may be realized by the integration of nanodiamond particles with optical fibers and volumetric doping of the particles alongside the fiber core. That approach combines the advantages of robust axial fixation of...