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Search results for: underwater%20communications
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ECHOES REDUCTION DURING DIGITAL DATA TRANSMISSION IN HYDROACOUSTIC CHANNEL – LABORATORY EXPERIMENT
PublicationThe possibility of using a hydroacoustic channel for digital data transmission is very limited. This is due to the effect of multipath propagation of the emitted acoustic wave and the damping of the mechanical wave in this medium, which increase with frequency. The first of these phenomena results in inter-symbol interference disturbances in data transmission systems, including even hundreds of symbols. Due to the number of reflections...
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Offshore benthic habitat mapping based on object-based image analysis and geomorphometric approach. A case study from the Slupsk Bank, Southern Baltic Sea
PublicationBenthic habitat mapping is a rapidly growing field of underwater remote sensing studies. This study provides the first insight for high-resolution hydroacoustic surveys in the Slupsk Bank Natura 2000 site, one of the most valuable sites in the Polish Exclusive Zone of the Southern Baltic. This study developed a quick and transparent, automatic classification workflow based on multibeam echosounder and side-scan sonar surveys to...
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Substrate Integrated Waveguide-Based Frequency-Tunable Self-Octaplexing Antenna
PublicationThis communication presents the first-ever substrate integrated waveguide (SIW)-based frequency-tunable self-octaplexing antenna (SOA) for wireless communication. The structure is arranged by implementing eight distinct patches with planar 50-ohm feedlines at the top of the SIW cavity, which realize eight distinct resonant frequencies. Independent tuning of each resonant frequency is achieved by incorporating appropriately allocated...
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Wireless Link Selection Methods for Maritime Communication Access Networks—A Deep Learning Approach
PublicationIn recent years, we have been witnessing a growing interest in the subject of communication at sea. One of the promising solutions to enable widespread access to data transmission capabilities in coastal waters is the possibility of employing an on-shore wireless access infrastructure. However, such an infrastructure is a heterogeneous one, managed by many independent operators and utilizing a number of different communication...
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Code development of a DSP-FPGA based control platform for power electronics applications
PublicationThis paper focuses on the implementation of power electronics algorithms in control platforms based on DSP-FPGA. Today’s power electronics technology demands high power computation with high speed interfacing at the same time. The most popular configuration is a DSP for the former and a FPGA for the latter. The main goal of this work was to develop a generic control system for power electronics application, but it is explained...
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3D seafloor reconstruction using data from side scan and synthetic aperture sonar
PublicationSide scan and synthetic aperture sonars are widely used imaging systems in the underwater environment. They are relatively cheap and easy to deploy, in comparison with more powerful sensors, like multibeam echosounders. Although side scan and synthetic aperture sonars does not provide seafloor bathymetry directly, their records are finally related to seafloor images. Moreover, the analysis of such images performed by human eye...
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Simple empirical formula to estimate the main geomechanical parameters of preplaced aggregate concrete and conventional concrete
PublicationPreplaced aggregate concrete (PAC) or two-stage concrete is a specific type of concrete successfully employed in many projects including underwater concrete structures, massive concrete structures, structures made of reinforced concrete, and improvement of concrete structures. PAC is significantly different than the conventional concrete. In this type of concrete, aggregates are initially poured into the mold, the voids between...
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Raman investigation of the patina layers on Hungarian copper ingots from a fifteenth century shipwreck
PublicationWe report results of the patina study of underwater archeological finding ofmedieval copper objects performed by means of the Raman and complementary spectroscopic techniques. The objects were found submerged in the sea as cargo part of the ship which sunk in the Gulf of Gdańsk in 1408. The excavated collection consists of 230 oval ingots of the size and mass up to about 60 cm and 18 kg (total of 2 tons), respectively. In the Raman...
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Self-assembly of zinc and cobalt complexes mimicking active site of alcohol dehydrogenase
PublicationPo raz pierwszy zsyntetyzowano obojętne kompleksy cynku i kobaltu naśladujące strukturę centrum aktywnego dehydrogenazy alkoholowej z wodą jako dodatkowym ligandem. Jakość otrzymanych kryształów pozwoliła na szczegółową analizę wewnątrzcząsteczkowych wiązań wodorowych w kryształach tych związków. Wnioski potwierdzono za pomocą spektroskopii FT-IR w ciele stałym.
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Efficient parallel algorithms in global optimization of potential energy functions for peptides, proteins, and crystals
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First-order impulsive functional differential equations
PublicationPraca dotyczy problemów istnienia rozwiązań i kwazi-rozwiązań dla równań różniczkowych rzędu pierwszego z impulsami i nieliniowymi warunkami brzegowymi. Operator występujący w zagadnieniu jest typu opóźnionego. Badano również nierówności różniczkowe z impulsami związane z zagadnieniem wyjściowym. Otrzymane wyniki zilustrowano na przykładach.
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Investigations on the influence CuO doping on elastic properties of Li2SO4–MgO–P2O5 glass system by means of acoustic wave propagation
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Effect of a characteristic length on crack spacing in a reinforced concrete bar under tension
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Chemical instability of the cobalt oxyhydrate superconductor under ambient conditions
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Superconductivity in three-layer Na0.3CoO2·1.3H2O
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The effect of Fe and Ru substitution on the superconductivity in MgCNi3
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Novel zinc complexes with acetyloacetonate, imidazole and thiolate ligands: Crystal structure of a zinc complex of relevance to farnesyl transferase
PublicationOtrzymano dwa nowe kompleksy cynku z ligandami S-,N- i O-donorowymi i scharakteryzowano je za pomocą rentgenowskiej analizy strukturalnej i spektroskopii w podczerwieni. Jeden z tych kompleksów jest pierwszym kompleksem modelującym centrum aktywne transferazy farnezylu.
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k-Penalty: A Novel Approach to Find k-Disjoint Paths with Differentiated Path Costs
PublicationW artykule rozpatrywany jest problem ochrony dedykowanej na wypadek awarii wielokrotnej elementów sieci teleinformatycznej. Wspomniana ochrona jest możliwa do zapewnienia poprzez wyznaczenie i zainstalowanie zbioru k rozłącznych ścieżek dla każdego żądania. W szczególności rozpatrywany jest problem wyznaczenia k rozłącznych ścieżek w sieciach typu ''multi-cost'', w przypadku których koszt dowolnego łącza może być różny dla każdej...
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In-situ synthesis and characterization of biocompatible magnetic ginger nanofiber composites for copper (II) removal from water
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Magnetic properties of charge ordered complex TCNQ salts with lattice distortions
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Networks 2010 Conference in Warsaw, Poland
PublicationArtykuł sprawozdawczy z konferencji.
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IEEE RNDM 2010 Workshop, Moscow, Russia
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Systems of differential equations with a singular matrix
PublicationPraca dotyczy układów równań różniczkowych z macierzą osobliwą. Szczególnymi przypadkami takich układów są równania różniczkowo-algebraiczne. Korzystając z odpowiedniej nierówności różniczkowej dla układów równań i metody quasi linearyzacji pokazano, iż odpowiednie monotoniczne ciągi są zbieżne do rozwiązania naszego problemu i jest to zbieżność kwadratowa. O funkcji f występującej po prawej stronie zagadnienia zakładano...
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Synthesis of parametric images in the medical active thermography
PublicationArtykuł przedstawia zastosowanie nowej metody syntezy obrazów w termografii dla potrzeb opisu ilościowego właściwości termicznych tkanek. opis taki umożliwia różnicowanie przypadków medycznych. Metodę zastosowania dla licznych pomiarów fantomowych oraz in vitro. Przedstawiono i omówiono rezultaty prac.
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Multiphase separated polyurethanes studied by micro Raman spectroscopy.
PublicationPrzedmiotem badań były poliuretany o zawartości 30% segmentów sztywnych,charakteryzujące się obecnością globul i sferolitów. Badania za pomocą mikro Ramana wykazały różny skład chemiczny w wymienionych mikroobszarach. W globulach stwierdzono zanik obecności segmentów giętkich lub ich bardzo znikomą ilość w porównaniu z matrycą i sferolitami.
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Structural and electrical transport studies of reduced in hydrogen surfaceof bismuth germanate glass
PublicationOtrzymano nanostruktury krystalicznego bizmutu w matrycy szkła germanowegooraz warstwę nanostruktur krystalicznego bizmutu na powierzchni redukowanegow atmosferze wodoru szkła Bi0.33Ge0.67O1.83. Zaproponowano prosty model bu-dowy zredukowanych szkieł bizmutowo-germanowych potwierdzony wynikami badańAFM i XRD. Zbadano wpływ czasu i temperatury redukcji oraz topnienia bizmu-tu na własności elektryczne badanych szkieł. Przeanalizowano...
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Chemical instability of the cobalt oxyhydrate superconductor under ambientconditions.
PublicationPrzedstawiono badania dyfrakcyjne i termograwimetryczne uwodnionego, sodowo-kobaltowego tlenku nadprzewodzącego: NaxCoO2 yH2O (y=1.4). Materiał ten jest niestabilny już w temperaturze pokojowej i przechodzi w nowo odkrytą fazę = 0.6.
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In silico study on the effects of carbonyl groups on chemical equilibrium of reactions with a polar product occurring under confinement in pores of activated carbons
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Influence of phonon-phonon coupling on superconducting state in honeycomb-type crystal lattice
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ARUZ — Large-scale, massively parallel FPGA-based analyzer of real complex systems
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Superconducting state in the atomic metallic hydrogen just above the pressure of the molecular dissociation
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The superconducting state in the B2H6 compound at 360GPa
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Description of the thermodynamic properties of BiH 5 and BiH 6 superconductors beyond the mean-field approximation
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Magnetic Molecularly Imprinted Polymer Particles Synthesized by Suspension Polymerization in Silicone Oil
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Synthesis and photochemical properties of unsymmetrical phthalocyanine bearing two 1-adamantylsulfanyl groups at adjacent peripheral positions
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The influence of of cross-linking process on the physicochemical properties of new copolyesters containing xylitol
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Synthesis, characterization, photochemical properties and cytotoxicity of the novel porphyrazine functionalized with nitroimidazolylbutylsulfanyl groups
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Synthesis, spectroscopic and photophysical properties of novel styryldiazepinoporphyrazine
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The exponential law for partial, local and proper maps and its application to otopy theory
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Erbium (III) molybdate as a new nanofiller for fabrication of antifouling polyethersulfone membranes
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Inspired by Nature: The Use of Plant-derived Substrate/Enzyme Combinations to Generate Antimicrobial Activity in situ
PublicationThe last decade has witnessed a renewed interest in antimicrobial agents. Plants have received particular attention and frequently rely on the spontaneous enzymatic conversion of an inactive precursor to an active agent. Such two-component substrate/enzyme defence systems can be reconstituted ex vivo. Here, the alliin/alliinase system from garlic seems to be rather effective against Saccharomyces cerevisiae, whilst the glucosinolate/myrosinase...
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On rotary inertia of microstuctured beams and variations thereof
PublicationWe discuss the classic rotary inertia notion and extend it for microstructured beams introducing new microinertia parameters as an additional dynamic response to microstructure changes. Slender structures made of beam- or platelet-lattice metamaterials may exhibit not only large translations and rotations but also general deformations of inner structure. Here we considered a few examples of beam-like structures and derive their...
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On the Importance of Resilience Engineering for Networked Systems in a Changing World
PublicationResilience is featured increasingly often in the media, usually applied to society when faced, for example, with disasters such as flooding and the enormous challenges that the Covid-19 pandemic posed. There are now many resilience-related discussion groups worldwide, and some standards initiatives devoted in particular to city resilience. However, there is relatively little explicit interest in resilience engineering for communication...
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Characteristics of silver-dopped carbon nanotube coating destined for medical applications
PublicationCarbon nanotubes are materials demonstrating outstanding mechanical, chemical, and physical properties and are considered coatings of titanium implants. The present research is aimed to characterize the microstructure and properties of the multi-wall carbon nanotubes (MWCNTs) layer decorated with silver nanoparticles (Ag NPs) on the Ti13Nb13Zr alloy destined for long-term implants. The electrophoretic deposition of coatings...
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Enhanced cellulose extraction from agave plant (Agave americana Species) for synthesis of magnetic/cellulose nanocomposite for defluoridation of water
PublicationResearch on fluoride removal from water is currently focusing on the development of innovative materials for defluoridation water. The current study extracted and used enhanced cellulose from Agave americana species to synthesize a magnetic/cellulose nanocomposite for water defluoridation. Strong and light binary acids (H2SO4 and CH3COOH) were utilized to pretreat raw material to enhance cellulose extraction. Central composite...
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The first manganese trialkoxysilanethiolates: formation, properties and structure of solvent ligated complexes - [Mn{SSi(OBut)3}2(MeCN)] and [Mn{SSi(OBut)3}2(MeOH)4]
PublicationW pracy przedstawiono otrzymywanie i strukturę pierwszych trialkoksysilanotiolanowych kompleksów manganu(II). Syntezy prowadzone były reakcji 2≡SiSH+ MnCl2 + 2Et3N = (≡SiS)2Mn + 2Et3N.HCl doprowadziły do otrzymania nowych kompleksów: [Mn{SSi(OBut)3}2(MeOH)4] (gdy jako rozpuszczalnik zastosowano MeOH) oraz [Mn{SSi(OBut)3}2(NCCH3)], gdy w badaniach posłużono się acetonitrylem.
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LOS and NLOS identification in real indoor environment using deep learning approach
PublicationVisibility conditions between antennas, i.e. Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) can be crucial in the context of indoor localization, for which detecting the NLOS condition and further correcting constant position estimation errors or allocating resources can reduce the negative influence of multipath propagation on wireless communication and positioning. In this paper a deep learning (DL) model to classify LOS/NLOS...
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Path integrals formulations leading to propagator evaluation for coupled linear physics in large geometric models
PublicationReformulating linear physics using second kind Fredholm equations is very standard practice. One of the straightforward consequences is that the resulting integrals can be expanded (when the Neumann expansion converges) and probabilized, leading to path statistics and Monte Carlo estimations. An essential feature of these algorithms is that they also allow to estimate propagators for all types of sources, including initial conditions....
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Crystal structure and physical properties of AePd1-xP1+x (Ae = Ca, Sr)
PublicationWe report the discovery of two new compounds AePd1-xP1+x (Ae = Ca, Sr) crystallized in different hexagonal structures. Single crystals of AePd1-xP1+x (Ae = Ca, Sr) are obtained using the Bi-flux method. Crystallographic analysis by both powder and single crystal X-ray diffraction shows that CaPd1-xP1+x crystallizes in a non-centrosymmetric hexagonal structure with the space group P-6m2 (No.187) and lattice parameters a = b = 4.0391(9)...
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Enhanced trap-assisted recombination in organic semiconductors
PublicationAn analytical model to describe the interaction of excitons and charge transfer states with deep traps is formulated for the case of molecular materials. Here, we have considered the influence of a trap-assisted recombination on this phenomenon. The final expression for the effective recombination rate has been derived from the Shockley–Read–Hall theory and kinetic equations which characterize different photophysical processes....