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Termination functions for evolutionary path planning algorithm
PublicationIn this paper a study of termination functions (stop criterion) for evolutionary path planning algorithm is presented. Tested algorithm is used to determine close to optimal ship paths in collision avoidance situation. For this purpose a path planning problem is defined. A specific structure of the individual path and fitness function is presented. For the simulation purposes a close to real tested environment is created. Five...
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Teaching High Performance Computing Using BeesyCluster and Relevant Usage Statistics
PublicationThe paper presents motivations and experiences from using the BeesyCluster middleware for teaching high performance computing at the Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology. Features of BeesyCluster well suited for conducting courses are discussed including: easy-to-use WWW interface for application development and running hiding queuing systems, publishing applications as services...
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Three-objective antenna optimization by means of kriging surrogates and domain segmentation
PublicationIn this paper, an optimization framework for multi-objective design of antenna structures is discussed which exploits data-driven surrogates, a multi-objective evolutionary algorithm, response correction techniques for design refinement, as well as generalized domain segmentation. The last mechanism is introduced to constrain the design space region subjected to sampling, which permits reduction of the number of training data samples...
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Genotyping of clinical isolates of fluconazole-resistant Candida albicans
PublicationThe aim of the study was to compare the discriminatory power of RAPD-PCR method with using RSD10 primer and microsatellite analysis with using (GACA)4 primer for genotyping clinical isolates of fluconazole-resistant C. albicans. Isolates were received from patients of Children's Memorial Health Institute in Warsaw. However in the case of both tested methods low number of amplified fragments was generated, nine and six different...
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The Potential of Greed for Independence
PublicationThe well-known lower bound on the independence number of a graph due to Caro and Wei can be established as a performance guarantee of two natural and simple greedy algorithms or of a simple randomized algorithm. We study possible generalizations and improvements of these approaches using vertex weights and discuss conditions on so-called potential functions p(G) : V(G) -> N_0 defined on the vertex set of a graph G for which suitably...
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Performance of the very high-temperature heat pump with low GWP working fluids
PublicationTraditional heat pumps are a very attractive pro-ecological solutions for a number of applications, including providing of heating or heat recovery from industrial processes. The application range of heat pumps could be greatly enlarged when the operating temperature would be increased to 130-150°C and/or the temperature lift can be increased to 50-100 K. In the paper, the very high temperature vapour-compressor based single stage...
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Spectral measurement of birefringence using particle swarm optimization analysis
PublicationThe measurement of birefringence is useful for the examination of both technical and biological objects. One of the main problems is that the polarization state of light in birefringent media changes periodically. Without the knowledge of the period number, the birefringence of a given medium cannot be determined reliably. We propose to analyse the spectrum of light in order to determine the birefringence. We use a Particle Swarm...
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Application of chromogenic dye in biogenic amines determination using spectrophotometry
PublicationBiogenic amines content can be the source of information in the field of freshness and suitability of certain foods for consumption. However, most analytical methods for their determination require complicated sample preparation and expert knowledge. Because of that, a novel approach based on chromogenic dye application was proposed. After the SN1 reaction of an amine with S 0378 dye, the absorbance of the solution was measured...
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Chromatic cost coloring of weighted bipartite graphs
PublicationGiven a graph G and a sequence of color costs C, the Cost Coloring optimization problem consists in finding a coloring of G with the smallest total cost with respect to C. We present an analysis of this problem with respect to weighted bipartite graphs. We specify for which finite sequences of color costs the problem is NP-hard and we present an exact polynomial algorithm for the other finite sequences. These results are then extended...
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Employment of passive sampling in monitoring indoor air quality in selected residences in a Tri-city area in Poland
PublicationTime-weighted average concentrations of selected volatile compounds were measured in chosen residences in a Tri-City area of Poland by means of passive sampling. The results were compared to those obtained by dynamic technique – sorption tubes filled with Tenax TA sorbent. Results obtained by employing the two techniques were similar. Total volatile organic compound (TVOC) parameters were also determined. An attempt was also...
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Mercury in various components of the environment (Gulf of Gdańsk, southern Baltic Sea)
PublicationTotal mercury concentration was determined monthly form January 2012 to May 2013 in the water (microlayer and the surface), plankton, epilithon, epiphyton, benthos and sediment. The study was conducted in the coastal zone of the Gulf of Gdańsk. The abundance and biomass of plankton, benthos; the concentration of suspended particulate matter, particulate organic carbon and nitrogen; δ13C and δ15N in the suspended matter; sediment...
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The changes of groundwater quality of the ''Czarny Dwór'' intake as a result of the aquifer vulnerability
PublicationThe "Czarny Dwór" groundwater intake is one of the main sources of water for Gdańsk. It is situated on the Marine Terrace and exploits mainly Quaternary aquifer, but also Tertiary and Cretaceous. The water is generally of good quality although some undesirable changes were observed in the Quaternary aquifer during almost 40 years of exploitation. The changes are caused by developing urbanization, former high pumping rates and...
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Application of road map of operating condition for estimation of fuel and electric energy consumption from city transport
PublicationThe paper presents procedure of data collecting and generation of road map of operating condition in the selected urban area. This map allows forecasting the selected vehicle operating parameters for the assumed road. The main parameters calculated using the road maps of operating conditions are: total energy spent to drive the selected vehicle, consumed fuel, travel time, average speed of travel, CO2 emissions. Presented example...
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Modal Analysis of Planar Elliptical Resonator Deposited on Unshielded Dielectric Slab
PublicationModal analysis of isolated open planar elliptical patch placed on dielectric slab is presented in the paper. It applies concept of Illuminating Modes which is formulated for the case of two-side opened structure. The current on patch is expanded in basis functions in form of Mathieu radial and angular functions. The spectrum of excited modes for exemplary planar resonators is presented and discussed using the concept of power of...
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The Effect of University Campuses on the Modal Split of Polish Cities
PublicationThe article considers the effect Polish public universities have on the characteristics of urban traffic. The article describes how the public university community has changed over 25 years and its share in the urban population. The characteristics of the modal split in Polish university towns is given based on selected cases. The relation between the share of transport modes in the modal split and the size of towns or university...
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4-[(tert-Butyldimethylsilyl)oxy]-6-methoxy-7-methyl-5-(oxiran-2-ylmethyl)-2-benzofuran-3(1H)-one
PublicationThe title compound, C19H28O5Si, was obtained in the reaction of 1,3-dihydro-4-[(tert-butyldimethylsilyl)oxy]-6-methoxy-7-methyl-3-oxo-5-(prop-2-enyl)isobenzofuran with meta-chloroperbenzoic acid. This reaction is one of the stages of the total synthesis of mycophenolic acid, which we attempted to modify. The title compound forms crystals with only weak intermolecular interactions. The strongest stacking interaction is found between...
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Reducing income inequalities through government expenditures on education. Evidence for European countries Piotr PłatkowskiORCID Icon &Ewa LechmanORCID Icon
PublicationThis study examines the role of government spending on education in mitigating income inequalities. The study uses dynamic panel regressions to assess the evolution of education expenditures and income inequality in the sample of 30 European countries between 1995 and 2018. Our findings show that increases in government spending on education positively affect income inequality reduction. The impact was more substantial in case...
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A Novel Versatile Decoupling Structure and Expedited Inverse-Model-Based Re-Design Procedure for Compact Single-and Dual-Band MIMO Antennas
PublicationMultiple-input multiple-output (MIMO) antennas are considered to be the key components of fifth generation (5G) mobile communications. One of the challenges pertinent to the design of highly integrated MIMO structures is to minimize the mutual coupling among the antenna elements. The latter arises from two sources, the coupling in the free space and the coupling currents propagating on a ground plane. In this paper, an array of...
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SEDIMENT DEPOSITION IN RESERVOIRS IN URBAN BASIN
PublicationIn recent years Gdańsk had sustained economic and social losses due to severe flash floods coming down from moraine hills. The first flood occurred in July 2001 and the second in July 2016. Both events were caused by intense and long rainfall characterized by different from each other rain intensity in time. Among other Gdansk’s streams the Oliwski Stream has the most extended flood protection system consist of 15 small retention...
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Prowadzenie ruchu małego źródła kogeneracji gazowej według kryterium efektu ekonomicznego
PublicationCechą charakterystyczną źródeł gazowych jest ich duża elastyczność ruchowa, w porównaniu do większości źródeł konwencjonalnych i odnawialnych. Cecha ta może i powinna być wykorzystywana do poprawy wskaźników ekonomicznych obiektu. W tym celu należy przeanalizować możliwości jakie daje prowadzenie ruchu źródeł nie w standardzie pracy z wymuszeniem zapotrzebowania na ciepło, ale właśnie maksymalnie wykorzystując elastyczność ruchową...
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Wpływ ekologicznych czynników roboczych na efektywność układu sprężarkowej pompy ciepła (The impact of environmentally friendly refrigerants on heat pump efficiency)
PublicationArtykuł poświęcony jest zagadnieniu symulacji pracy układu sprężarkowej pompy ciepła. Prawidłowe zaprojektowanie instalacji oraz jej właściwe użytkowanie pozwala na zmniejszenie kosztów eksploatacji. Dokładna analiza techniczno-ekonomiczna umożliwia natomiast dobór elementów systemu o możliwie największej sprawności, a zatem niskim zapotrzebowaniu na energię. Zastosowanie układów opartych o perspektywiczne, proekologiczne czynniki...
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Prowadzenie ruchu małej elektrociepłowni gazowej według kryterium efektu ekonomicznego
PublicationCechą charakterystyczną źródeł gazowych jest ich duża elastyczność ruchowa, w porównaniu do większości źródeł konwencjonalnych i odnawialnych. Cecha ta może i powinna być wykorzystywana do poprawy wskaźników ekonomicznych obiektu. W tym celu należy przeanalizować możliwości jakie daje prowadzenie ruchu źródeł nie w standardzie pracy z wymuszeniem zapotrzebowania na ciepło, ale właśnie maksymalnie wykorzystując elastyczność ruchową...
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Multi-objective optimization of the cavitation generation unit structure of an advanced rotational hydrodynamic cavitation reactor
PublicationHydrodynamic cavitation (HC) has been widely considered a promising technique for industrial-scale process intensifications. The effectiveness of HC is determined by the performance of hydrodynamic cavitation reactors (HCRs). The advanced rotational HCRs (ARHCRs) proposed recently have shown superior performance in various applications, while the research on the structural optimization is still absent. The present study, for the...
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The Influence of Drying Temperature on Color Change of Hornbeam and Maple Wood Used as Surface and Inner Layers of Wood Composites
PublicationThe thermal treatment of wood changes its structure due to the degradation of wood polymers (cellulose, hemicellulose and lignin), so the physical properties of wood are either improved or degraded. Color changes apply not only to natural wood, but also to such wood composites for which some amount of glue is used in their construction (e.g., plywood, blockboard or laminboard). This article is focused on the analysis of hornbeam...
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Effect of applied standard wood machining fluid on colour and chemical composition of the machined wood surface
PublicationAppropriate monitoring of wood machining processes is a key issue to ensure the expected quality of the processed wood, expected efficiency and minimize energy consumption of production processes. A new trend is the design of environmentally friendly machining fluids. In this paper, as a preliminary study in this field, the effect of applied standard wood machining fluid on changes in the colour and chemical composition of the...
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The chemistry of river–lake systems in the context of permafrost occurrence (Mongolia, Valley of the Lakes). Part I. Analysis of ion and trace metal concentrations
PublicationThis study provides a description of water chemistry in river–lake systems located in central Mongolia, at the borderline of permafrost occurrence. The analysis involved water samples collected from two river–lake systems: Baydrag River–Böön Tsagaan Lake system, and Shargalyuut/Tuyn Rivers–Orog Lake system. In the water samples, ions and trace elements were detected and quantified. Additionally, the parameters of pH, electrical...
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Long-term performance and microbial characteristics of the anammox-enriched granular sludge cultivated in a bench-scale sequencing batch reactor
PublicationThe anammox-enriched granular sludge was successfully formed during the long-term biogranulation experiment lasting over 330 days. The cultivation was conducted at 30 ◦C in a 10-L sequencing batch reactor (SBR) fed with synthetic medium containing ammonia, nitrite and trace elements. The properties of the developed granules were investigated in terms of the biomass activity (including the growth rate of anammox bacteria), size...
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Low to intermediate energy elastic electron scattering from dichloromethane (CH2Cl2)
PublicationWe report a theoretical-experimental investigation of electron scattering by dichloromethane (CH2Cl2) in the low- and intermediate energy ranges. Experimental elastic differential cross sections (DCS), in the incident electron energy range of 0.5-800 eV and scattering angle range of 10°–130°, were measured using a crossed beam relative flow technique. Integral and momentum- transfer cross sections were determined from the experimental...
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Assessment of the Bulgarian Wastewater Treatment Plants’ Impact on the Receiving Water Bodies
PublicationDeterioration of water quality is a major problem world widely according to many international non-governmental organizations (NGO). As one of the European Union (EU) countries, Bulgaria is also obliged by EU legislation to maintain best practices in assessing surface water quality and the efficiency of wastewater treatment processes. For these reasons studies were undertaken to utilize ecotoxicological (Microtox®, Phytotoxkit...
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Characterization methods of nickel nano-particles obtained by the ex-solution process on the surface of Pr, Ni-doped SrTiO3 perovskite ceramics
PublicationIn this paper, a novel electrode material based on Pr, Ni co-doped strontium titanate ( Sr0.7Pr0.3)xTi1−yNiyO3 with constant amount of 30% praseodymium dopant, different amount of nickel (y = 0.06 and y = 0.10) and additional nonstoichiometry in Sr-site (x = 1; x = 0.9 and x = 0.8) was investigated as fuel electrode for SOEC devices. A porous ceramics were prepared by solid-state reaction method. X-ray diffraction measurements...
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Electrical properties of A-site Ca-doped LaNb1-xAsxO4-δ ceramics
PublicationThe electrical properties of A-site Ca-doped LaNbO4 with the addition of As in the B-site, have been investigated. Total, grain- and specific grain boundary electric conductivities in different oxygen partial pressure, and water vapour partial pressure were determined. Additional conductivity measurements were performed in nitrogen, to suppress the possible p-type conductivity, focusing on protonic conductivity. The maximum measured...
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Theoretical examination of the fracture behavior of BC3 polycrystalline nanosheets: Effect of crack size and temperature
Publication2D carbon graphene nanostructures are elements of advanced materials and systems. This theoretical survey provides explanation to the mechanical and fracture behavior of mono- and polycrystalline BC3 nanosheets (denoted as MC- and PCBC3NS, respectively) as a function of temperature and the type of crack defects. The mechanical performance of PCBC3NS at elevated temperatures was monitored varying the number of grain boundaries (the...
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Surface diffusion and cluster formation of gold on the silicon (111)
PublicationPurpose: Investigation of the gold atoms behaviour on the surface of silicon by molecular dynamics simulation method. The studies were performed for the case of one, two and four atoms, as well as incomplete and complete filling of gold atoms on the silicon surface. Design/methodology/approach: Investigations were performed by the method of molecular dynamics simulation using the Large-scale Atomic/Molecular Massively Parallel...
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Electromagnetic Control and Dynamics of Generalized Burgers’ Nanoliquid Flow Containing Motile Microorganisms with Cattaneo–Christov Relations: Galerkin Finite Element Mechanism
PublicationIn our research work, we have developed a model describing the characteristics of the bio-convection and moving microorganisms in the flows of a magnetized generalized Burgers’ nanoliquid with Fourier’s and Fick’s laws in a stretchable sheet. Considerations have been made to Cattaneo–Christov mass and heat diffusion theory. According to the Cattaneo–Christov relation, the Buongiorno phenomenon for the motion of a nanoliquid in...
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A Single-Carrier-Based Pulse-Width Modulation Template for Cascaded H-Bridge Multilevel Inverters
PublicationMultiplicity of the triangular carrier signals is a criterion for the extension of sinusoidal pulsewidth modulation, SPWM, to a number of output voltage levels per phase-leg in cascaded H-bridge (CHB) multilevel inverter (MLI). Considering medium and high voltage applications where appreciable number of output voltage levels from CHB MLI is needed, commensurate high number of carrier signals in either classical level- or phase-shifted...
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Technical and Economic Analysis of the Implementation of Selected Variants of Road Investment
PublicationThe aim of the article is to analyze three variants of modernization and reconstruction of a road intersection, which in practice is the cause of numerous collisions and accidents. Detailed design solutions are presented for them. The aim of the analyses is to indicate an effective solution that, taking into account technical modifications of the road system elements, will ensure the functionality of the road system to the highest...
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The concept of stream and system reliability on the example of the bakery industry
PublicationThis article presents a new concept of technological system reliability based on the analysis of the relationship of associations of elements of energy streams, matter, information, time and finance. The method of stream specification and the method of determining the reliability values of significant and supporting relationships are given. Relevant relationships between elements of system streams were defined as having one-time...
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The reliability of any-hop star networks with respect to failures of communication nodes.
PublicationThis paper investigated the reliability of any-hop star networks. The any-hop star topology is used in centralized computer networks. We will assume that the all nodes fail independently, links are failure-free. Following measures of network reliability are assumed: the expected number of nodes, which can communicate with the central node; the expected number of node pairs, which are connected by a path through the central node;...
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Rapid Design of 3D Reflectarray Antennas by Inverse Surrogate Modeling and Regularization
PublicationReflectarrays (RAs) exhibit important advantages over conventional antenna arrays, especially in terms of realizing pencil-beam patterns without the employment of the feeding networks. Unfortunately, microstrip RA implementations feature narrow bandwidths, and are severely affected by losses. A considerably improved performance can be achieved for RAs involving grounded dielectric layers, which are also easy to manufacture using...
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New Method for Increasing Precision of Position Estimation of a Moving Person in Hybrid Inertial Navigation System
PublicationIn this article a new method for increasing precision of position estimation of inertial navigation in hybrid localization system with reduced number of reference nodes for radio distance measurements is presented. Measuring tests were carried out to verify precision of position estimation of moving person in indoor environment.
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Periodic points of latitudinal maps of the $m$-dimensional sphere
PublicationLet f be a smooth self-map of the m-dimensional sphere Sm. Under the assumption that f preserves latitudinal foliations with the fibres S1, we estimate from below the number of fixed points of the iterates of f. The paper generalizes the results obtained by Pugh and Shub and by Misiurewicz.
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Numerical single-phase modeling of turbulent flow and heat transfer of nanofluids
PublicationIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (6 000< Re < 12 000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with published experimental data.
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Nowe substancje psychoaktywne. Cz. I. Współczesna sytuacja narkotykowa
PublicationGwałtowny wzrost liczby substancji wprowadzanych na rynek narkotykowy został zaobserwowany już pod koniec lat dziewięćdziesiątych XX wieku. Każdego roku syntezowane są nowe substancje jako analogi już istniejących, a ich ilość systematycznie rośnie. Niejednokrotnie wprowadzenie niewielkiej zmiany w strukturze związku może spowodować znaczne zmiany ich właściwości fizykochemicznych oraz psychoaktywnych. Nowe substancje psychoaktywne...
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Cryptocurrencies as a speculative asset. How much uncertainty is included in cryptocurrency price?
PublicationThe aim of this paper is to examine the relationship between uncertainty indices (Geopolitical Uncertainty Index and Global Economic Policy Uncertainty Index) and cryptocurrencies. In order to conduct research, the authors collected the data on the major cryptocurrencies (Bitcoin, Ethereum, Tether, Dogecoin and USD coin) which account for 78% of the total market cap. Using panel OLS regression, this study finds that Bitcoin...
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Experimental analysis of wear resistance of compacts of fine-dispersed iron powder and tungsten monocarbide nanopowder produced by impulse pressing
PublicationThe paper presents the results of studying the structure and wear resistance of compacts produced from fine dispersed reduced iron powder (average particle size 3–mu m) with the addition of tungsten carbide (WC) nanopowder with the average particle size of 25–30 nm. The mass fraction of tungsten carbide (wolfram carbide) in the powder composition was 5% and 10% of the total mass. Impulse pressing was conducted using the modified...
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Intercomparison of TEC obtained from the IRI model to the one derived from GPS measurements
PublicationIRI (International Reference Ionosphere) is a well-known standard of the ionosphere, but nowadays GPS permanent observations are also the base of the regional and global ionosphere models. In this paper, comparison of TEC (Total Electron Content) derived from the IRI model to the global TEC parameters derived from GPS measurements is presented. Global TEC maps show, that GPS derived ionosphere models, in opposition to the IRI,...
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The Research of the Contamination Levels present in Samples of Precipitation and Surface Waters Collected from the Catchment Area Fuglebekken (Hornsund, Svalbard Archipelago)
PublicationPersistent organic pollutants (POPs) are contaminants that may appear in polar regions. In present work surface water was collected from the main stream water in the Fuglebekken basin. The precipitationsamples was collected from the near area by Polish Polar Station in Hornsund. The present investigationreveals the results of the analysis of these samples for their total phenols, formaldehyde, TOC, PAHs and PCBs content. The...
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System for tracking multiple trains on a test railway track
PublicationSeveral problems may arise when multiple trains are to be tracked using two IP camera streams. In this work, real-life conditions are simulated using a railway track model based on the Pomeranian Metropolitan Railway (PKM). Application of automatic clustering of optical flow is investigated. A complete tracking solution is developed using background subtraction, blob analysis, Kalman filtering, and a Hungarian algorithm. In total,...
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System for tracking multiple trains on a test railway track
PublicationSeveral problems may arise when multiple trains are to be tracked using two IP camera streams. In this work, real-life conditions are simulated using a railway track model based on the Pomeranian Metropolitan Railway (PKM). Application of automatic clustering of optical flow is investigated. A complete tracking solution is developed using background subtraction, blob analysis, Kalman filtering, and a Hungarian algorithm. In total,...
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Simulation studies into quayside transport and storage yard operations in container terminals
PublicationThe focus of the paper is on quayside transport and storage yard operations in the sea container terminals. Developed algorithms for solving the issues of load handling and storage space allocation have been applied in the frame of adopted simulation model. The criteria chosen for decision making involved the total makespan of vessel unloading and the utilisation levels of the transportation trucks. Recommendations for unloading...