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Application of genetic algorithms in graph searching problem
PublikacjaGraph searching is a common approach to solving a problem of capturing a hostile intruder by a group of mobile agents. We assume that this task is performed in environment which we are able to model as a graph G. The question asked is how many agents are needed to capture an arbitrary fast, invisible and smart intruder. This number is called the (edge) search number of G. The strategy which must be performed by agents is called...
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On-line ranking of split graphs
PublikacjaA vertex ranking of a graph G is an assignment of positive integers (colors) to the vertices of G such that each path connecting two vertices of the same color contains a vertex of a higher color. Our main goal is to find a vertex ranking using as few colors as possible. Considering on-line algorithms for vertex ranking of split graphs, we prove that the worst case ratio of the number of colors used by any on-line ranking algorithm...
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Integration of brood units in game universe
PublikacjaAn access to a great number of various services allows for decomposition of complex problems Developing a game universe usually involves creation of various units which can be encountered by a player. Those can be lonely or organized in broods animals and monsters wandering around the game world. In order to provide natural gaming experience those units should behave variously depending on the world situation. Those behaviours...
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Universities as Part of the Urban Transport System—Analysis Using the Example of the Gdansk University of Technology and Medical University of Gdansk
PublikacjaMany cities perceive academic function as a distinctive feature, representing the rank and prestige of the city. Universities provide places for work and learning for a high number of people and represent a significant proportion compared to the total city population (even 22%). Many of Polish universities are located in the urban structure in the form of spatially concentrated campuses, where the number of people working and studying...
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A taxonomy of challenges to resilient message dissemination in VANETs
PublikacjaInter-vehicular communications is seen as a promising solution to a number of issues related with public road safety, road congestion management, and infotainment. However, Vehicular Ad-hoc NETworks (VANETs) characterized by high mobility of vehicles and facing a number of other issues related with high frequency wireless communications and network disconnections, encounter major challenges related with reliability of message delivery....
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Selektywne chłodzenie mózgu noworodka po niedotlenieniu okołoporodowym. Cześć 2. Koncepcja hybrydowego systemu selektywnego chłodzenia mózgu noworodka
PublikacjaMózg ludzki jest organem delikatnym, dlatego tak ważne jest zadbanie o to, aby już w momencie przyjścia na świat noworodek miał zapewnioną, w razie konieczności możliwość minimalizacji uszkodzeń neurologicznych, spowodowanych niedotlenieniem okołoporodowym. Niedotlenienie to w dramatyczny sposób zaburza homeostazę mózgu, który jako organ najbardziej energochłonny potrzebuje najwięcej tlenu. Zapoczątkowane brakiem tlenu procesy...
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A Simulative Comparison of Ship Domains and Their Polygonal Approximations
PublikacjaThe paper investigates the impact of a precise ship domain shape on the size of collision avoidance manoeuvres. The considered collision avoidance manoeuvres include both course and speed alterations. Various ship domains are compared with their polygonal approximations, which vary in the number of points of a domain contour and placement of these points. The best of all considered approximations is determined in the course of...
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EFFECT OF NANOFLUID CONCENTRATION ON TWO-PHASE THERMOSYPHON HEAT EXCHANGER PERFORMANCE
PublikacjaAn approach – relaying on application of nanofluid as a working fluid, to improve performance of the two-phase thermosyphon heat exchanger (TPTHEx) has been proposed. The prototype heat exchanger consists of two horizontal cylindrical vessels connected by two risers and a downcomer. Tube bundles placed in the lower and upper cylinders work as an evaporator and a condenser, respectively. Distilled water and nanofluid water-Al2O3...
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Frequency-Reconfigurable Hybrid SIW-Based Self-Diplexing Antenna Using Solid and Liquid Dielectric Loading
PublikacjaThis paper presents a novel frequencyreconfigurable self-diplexing antenna (SDA) utilizing a hybrid substrate-integrated waveguide (SIW). The antenna comprises a radiating slot, a feeding network, and a hybrid SIW cavity featuring half-mode circular and half-mode rectangular SIW structures. The unique feature of this antenna lies in its fine-tuning capability of each resonant frequency by inserting or injecting solid and liquid...
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Numerical Modelling of Connections Between Stones in Foundations of Historical Buildings
PublikacjaThe aim of this paper is to analyse the behaviour of old building foundations composed of stones (the main load-bearing elements) and mortar, based on numerical analysis. Some basic aspects of historical foundations are briefly discussed, with an emphasis on their development, techniques, and material. The behaviour of a foundation subjected to the loads transmitted from the upper parts of the structure is described...
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Refined theoretical study of radiative association: Cross sections and rate constants for the formation of SiN
PublikacjaRadiative 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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Carbon Dioxide and Water Vapour Fluxes of a Alkaline Fen and Their Dependence on Reflectance
PublikacjaThis study shows results of parallel measurements of greenhouse gases fluxes (carbon dioxide and water vapour) and canopy reflectance of alkaline fen. Fluxes were measured using eddy-covariance technique on micrometeorological station located in the Upper Biebrza Basin (NE Poland) in Rogożynek Village. Study site is located in the Biebrza National Park which was established to protect one of the biggest coherent lowland wetland...
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Rapid redesign of multiband antennas with respect to operating conditions and material parameters of substrate
PublikacjaThis work addresses geometry parameter scaling of multi-band antennas for Internet of Things applications. The presented approach is comprehensive and permits re-design of the structure with respect to both the operating frequencies and material parameters of the dielectric substrate. A two-step procedure is developed with the initial design obtained from an inverse surrogate model constructed using a set of appropriately prepared...
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Eqiuitable coloring of corona products of cubic graphs is harder than ordinary coloring
PublikacjaA graph is equitably k-colorable if its vertices can be partitioned into k independent sets in such a way that the number of vertices in any two sets differ by at most one. The smallest k for which such a coloring exists is known as the equitable chromatic number of G. In this paper the problem of determinig the equitable coloring number for coronas of cubic graphs is studied. Although the problem of ordinary coloring of coronas...
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Pipelined Two-Operand Modular Adders
PublikacjaPipelined two-operand modular adder (TOMA) is one of basic components used in digital signal processing (DSP) systems that use the residue number system (RNS). Such modular adders are used in binary/residue and residue/binary converters, residue multipliers and scalers as well as within residue processing channels. The structure of pipelined TOMAs is usually obtained by inserting an appropriate number of pipeline register layers within...
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Numerical Study of Turbulent Flow and Heat Transfer of Nanofluids in Pipes
PublikacjaIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (Reynolds number between 6000 and 12000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with experimental data. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO2 nanoparticles are used as nanofluid...
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Brushing with additional cleaning restrictions
PublikacjaIn graph cleaning problems, brushes clean a graph by traversing it subject to certain rules. We consider the process where at each time step, a vertex that has at least as many brushes as incident, contaminated edges, sends brushes down these edges to clean them. Various problems arise, such as determining the minimum number of brushes (called the brush number) that are required to clean the entire graph. Here, we study a new variant...
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Road safety analysis in Poland using time-series modelling techniques
PublikacjaA number of international studies argue that there is a correlation between the number of traffic fatalities and the degree of public activity. The studies use the unemployment rate to support that argument. As unemployment grows miles travelled fall, a factor known to affect road safety. This relationship seems to be true for Poland, as well. The model presented in the paper is intended to prove it. It is a structural time-series local...
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METHOD OF ROUTING SHIPS SAILING IN DEDICATED ENVIRONMENT
PublikacjaThe method for determining the suboptimal route of sailing vessels operating in a restricted area of the sea are proposed in the paper. The dynamics of the environment including weather conditions and speed characteristics of ships sailing are considered. As optimiza-tion criterion, measure sailing time T, and the number of maneuvers performed ω, are taken into account. An heuristic algorithm, and the appropriate application routing...
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Erratum to "Formulas and Theorems for the Special Functions of Mathematical Physics" by W. Magnus, F. Oberhettinger, R. P. Soni
PublikacjaWe correct a number of misprints in the handbook "Formulas and theorems for the special functions of mathematial physics" (3rd edition) by Magnus, Oberhettinger and Soni.
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Strategic balance in graphs
PublikacjaFor a given graph G, a nonempty subset S contained in V ( G ) is an alliance iff for each vertex v ∈ S there are at least as many vertices from the closed neighbourhood of v in S as in V ( G ) − S. An alliance is global if it is also a dominating set of G. The alliance partition number of G was defined in Hedetniemi et al. (2004) to be the maximum number of sets in a partition of V ( G ) such that each set is an alliance. Similarly,...
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Mathematical modeling and prediction of pit to crack transition under cyclic thermal load using artificial neural network
PublikacjaThe formation of pitting is a major problem in most metals, which is caused by extremely localized corrosion that creates small holes in metal and subsequently, it changes into cracks under mechanical load, thermo-mechanical stress, and corrosion process factors. This research aims to study pit to crack transition phenomenon of steel boiler heat tubes under cyclic thermal load, and mathematical modeling...
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Total Completion Time Minimization for Scheduling with Incompatibility Cliques
PublikacjaThis paper considers parallel machine scheduling with incompatibilities between jobs. The jobs form a graph equivalent to a collection of disjoint cliques. No two jobs in a clique are allowed to be assigned to the same machine. Scheduling with incompatibilities between jobs represents a well-established line of research in scheduling theory and the case of disjoint cliques has received increasing attention in recent...
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Scaling of numbers in residue arithmetic with the flexible selection of scaling factor
PublikacjaA scaling technique of numbers in resudue arithmetic with the flexible selection of the scaling factor is presented. The required scaling factor can be selected from the set of moduli products of the Residue Number System (RNS) base. By permutation of moduli of the number system base it is possible to create many auxilliary Mixed-Radix Systems associated with the given RNS with respect to the base, but they have different sets...
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The Use of an Autoencoder in the Problem of Shepherding
PublikacjaThis paper refers to the problem of shepherding clusters of passive agents consisting of a large number of objects by a team of active agents. The problem of shepherding and the difficulties that arise with the increasing number of data describing the location of agents have been described. Several methods for reducing the dimensionality of data are presented. Selected autoencoding method using a Restricted Boltzmann Machine is...
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Depth Determination Accuracy of the Modified Prony Method in a Swath Mapping Application
PublikacjaThis article presents the performance of the modified Prony method in a swath mapping application. Depth determination accuracy is assessed by processing raw signal acquired by an EdgeTech 6205 swath bathymetry system over flat seafloor. An updated version of the method, proposed previously by the authors, is used to determine the number of signal echoes. The number of signal echoes is essential for performing the low-rank approximation...
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POSSIBILITY OF ASSESSMENT OF OPERATION OF SLIDING BEARINGS IN PISTON-CRANK MECHANISMS OF DIESEL ENGINES WITH REGARD TO LOAD AND TIME OF CORRECT WORK OF THE BEARINGS BY APPLYING ACOUSTIC EMISSION AS A DIAGNOSTIC SIGNAL
PublikacjaAbstract: The paper presents a possibility of determining (assessing) operation of sliding bearings with multilayer bushings in crank-piston mechanisms of diesel engines. Properties of load and wear, particularly fatigue and abrasive, are characterized in general. Acoustic emission as a diagnostic signal was proved to be useful for detection of the wear of sliding and barrier layers. Results of measurements of acoustic emission...
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Turbulence model evaluation for numerical modelling of turbulent flow and heat transfer of nanofluids
PublikacjaIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (Reynolds number between 6000 and 12000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with experimental data. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO2 nanoparticles are used as nanofluid...
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New potential functions for greedy independence and coloring
PublikacjaA potential function $f_G$ of a finite, simple and undirected graph $G=(V,E)$ is an arbitrary function $f_G : V(G) \rightarrow \mathbb{N}_0$ that assigns a nonnegative integer to every vertex of a graph $G$. In this paper we define the iterative process of computing the step potential function $q_G$ such that $q_G(v)\leq d_G(v)$ for all $v\in V(G)$. We use this function in the development of new Caro-Wei-type and Brooks-type...
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On the Origin of Protein Superfamilies and Superfolds
PublikacjaDistributions of protein families and folds in genomes are highly skewed, having a small number of prevalent superfamiles/superfolds and a large number of families/folds of a small size. Why are the distributions of protein families and folds skewed? Why are there only a limited number of protein families? Here, we employ an information theoretic approach to investigate the protein sequence-structure relationship that leads to...
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Why is TASK Quarterly a Significant Journal to Publish Your Article? —A Bibliometric Analysis of a Scientific and Technical Journal
PublikacjaA bibliometric analysis of TASK Quarterly in the years 1997-2021 in terms of various bibliometric indicators was performed to celebrate the 25th anniversary of the publication of the first issue of the journal. The number of publications and citations increased over the mentioned span of years. The leading countries in terms of the greatest number of papers published in TASK Quarterly are Poland, Italy, Germany, Ukraine, USA and...
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Benefit of the doubt approach to assessing the research performance of Australian universities
PublikacjaThis paper proposes a benefit of the doubt (BoD) approach to assess the research performance of 37 public Australian universities based on data from 2015. The primary activities of Higher Education institutions are teaching and research, but the prestige of a university depends mainly on the results of its research activities. The BoD method is rooted in the data envelopment analysis methodology, which enables the flexible and...
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UNDECLARED WORK IN POLAND CHARACTERISTICS AND PREVALENCE
PublikacjaThis article aims to present the significance and prevalence of the phenomenon of undeclared work. First, we discuss the definitional issues of this phenomenon. Then, we present previous estimates on shadow economy and undeclared work in Poland, based on statistics provided by Central Statistical Office and other research entities. Our analysis covers the years 2000–2014. In the last part of the article, we use data from the Labour...
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Teaching civil engineering in English at Gdansk University of Technology
PublikacjaThe effects of globalization, as well as many possibilities of easy and cheap ways of travelling, have led to the increase in number of different types of university studies conducted in English. This paper describes advantages and disadvantages after seven years of experience of conducting three-semester MSc Studies in Civil Engineering in English at Gdansk University of Technology, Poland. The studies started in 2009 after a...
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Persulfates to degrade a mixture of dyes (rhodamine B, methylene blue) in the presence of glucose and visible light
PublikacjaA treatment process utilizing visible-light-activated (Vis) persulfates (PS) in the presence of an organic promoter (glucose) was developed for the simultaneous decolorization of a rhodamine B (RhB) and methylene blue (MB) mixture. Various doses of glucose, PS concentrations, pH values, initial dye concentrations and process time were tested to find out the most appropriate parameters for degrading the RhB/MB mixture in the...
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Noise Analysis of Continuous GPS Time Series of Selected EPN Stations to Investigate Variations in Stability of Monument Types
PublikacjaThe type of monument that a GPS antenna is placed on plays a significant role in noise estimation for each permanent GPS station. In this research 18 Polish permanent GPS stations that belong to the EPN (EUREF Permanent Network) were analyzed using Maximum Likelihood Estimation (MLE). The antennae of Polish EPN stations are placed on roofs of buildings or on concrete pillars. The analyzed data covers a period of 5 years from 2008...
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Modelling AOB-NOB competition in shortcut nitrification compared with conventional nitrification-denitrification process
PublikacjaIn particular, mainstream deammonification and/or shortened nitrificationdenitrification via nitrite (so-called “nitrite shunt”) is a promising new treatment concept that has the potential to revolutionise how nitrogen removal is achieved at WWTPs. Understanding the role of the AOB/NOB competition in the nitrogen cycle in wastewater treatment systems will change operational strategies of the novel nitrogen removal processes. The...
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Polycyclic aromatic hydrocarbons as test probes to investigate the retention behavior of 1,3-alternate calix[4]arene silica-bonded stationary phases
PublikacjaA series of polycyclic aromatic hydrocarbons (PAHs) of different size and shape has been used to characterize the chromatographic behavior of five calix[4]arene stationary phases in 1,3-alternate conformation synthesized in our laboratory. The selection of linear, fourring nonlinear, and five-ring PAHs gave data on selectivity changes across range of the calix[4]arene columns. Retention of the 12 aromatic solutes has been evaluated...
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Magneto-thermal convection of low concentration nanofluids
PublikacjaThe main aim of this paper was to analyze possible utilization of the low concentration nanofluids and the magnetic field to enhance heat transfer. The studied fluids were based on water with an addition of copper particles (40-60 nm diameter). They belonged to the diamagnetic group of materials. As a first attempt to stated target the analysis of enclosure placed in the maximal value of square magnetic induction gradient was carried...
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Physical properties and electronic structure of La3Co and La3Ni intermetallic superconductors
PublikacjaLa3Co and La3Ni are reported superconductors with transition temperatures of 4.5 and 6 K, respectively. Here, we reinvestigate the physical properties of these two intermetallic compounds with magnetic susceptibility χ, specific heat Cp and electrical resistivity ρ measurements down to 1.9 K. Although bulk superconductivity is confirmed in La3Co, as observed previously, only a trace of it is found in La3Ni, indicating that the...
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Experimental study on the behaviour of steel columns under seismic-induced axial impact load
PublikacjaIt has been observed during major earthquakes that the so called soft-storey failure of an upper floor of a structure results in large impact load acting on structural members of the lower storeys. It may further lead to progressive collapse of the whole structure substantially intensifying human and material losses. Therefore, the aim of this paper is to investigate experimentally the behaviour of columns under bending (observed...
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Superconductivity in the Cu(Ir1-xPtx)2Se4 spinel
PublikacjaWe report the observation of superconductivity in the CuIr2Se4 spinel induced by partial substitution of Pt for Ir. The optimal doping level for superconductivity in Cu(Ir1-xPtx )2Se4 is x = 0.2, where Tc is 1.76 K. A superconducting Tc vs composition dome is established between the metallic, normal conductor CuIr2Se4 and semiconducting CuIrPtSe4. Electronic structure calculations show that the optimal Tc occurs near the electron count...
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Bound on Bell inequalities by fraction of determinism and reverse triangle inequality
PublikacjaIt is an established fact that entanglement is a resource. Sharing an entangled state leads to nonlocal correlations and to violations of Bell inequalities. Such nonlocal correlations illustrate the advantage of quantum resources over classical resources. In this paper, we quantitatively study Bell inequalities with 2 × n inputs. As found in Gisin et al. [Int. J. Quantum. Inform. 05, 525 (2007)], quantum mechanical correlations...
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Algorytmy hybrydowe optymalizacji w zastosowaniu do problemu sterowania systemami dystrybucji wody
PublikacjaW pracy analizowany jest problem optymalizującego zintegrowanego sterowania ilością i jakością w systemach dystrybucji wody. Proponowane decyzje i sterowania powinny zapewniać optymalizację przyjętego wskaźnika jakości, przy spełnieniu ograniczeń właściwych tej klasie systemów. Ostatecznie do rozwiązania złożonych zadań optymalizacji dynamicznej zaproponowane zostało podejście hybrydowe, wspomagające predykcyjne algorytmy sterowania...
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ECONOMIC GROWTH AND FEMALE LABOR FORCE PARTICIPATION – VERIFYING THE U-FEMINIZATION HYPOTHESIS. NEW EVIDENCE FOR 162 COUNTRIES OVER THE PERIOD 1990-2012.
PublikacjaThe paper contributes by providing new insights into relationship between female labor force and economic growth in 162 world countries over the period 1990-2012. It is anticipated uncovering U-shaped relationship between female labor force participation and economic growth. The analysis is run in two different perspectives – first the relationship is examined for sample encompassing 162 countries; and second – the evidence is...
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Valence and Ionic Lowest-Lying Electronic States of Isobutyl Formate Studied by High-Resolution Vacuum Ultraviolet Photoabsorption, Photoelectron Spectroscopy, and Ab Initio Calculations
PublikacjaThe highest resolution vacuum ultraviolet photoabsorption spectrum of isobutyl formate, C5H10O2, yet reported is presented over the energy range 4.5−10.7 eV (275.5−118.0 nm) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series observed in the photoabsorption spectrum have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator...
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Levels of 13 multi-class pesticide residues in Polish honeys determined by LC-ESI-MS/MS
PublikacjaLevels of 13 pesticides in 40 honey samples form Poland are reported. A rapid and sensitive method was developed for the LC-ESI-MS/MS determination of multi-class pesticide residues in honey samples. Liquid-liquid extraction (LLE) on a diatomaceous earth support (requiring the use of small amounts of organic solvent), followed by chromatographic separation on a C18 column and gradient elution were employed. The method quantifies...
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Prediction of Wastewater Quality at a Wastewater Treatment Plant Inlet Using a System Based on Machine Learning Methods
PublikacjaOne of the important factors determining the biochemical processes in bioreactors is the quality of the wastewater inflow to the wastewater treatment plant (WWTP). Information on the quality of wastewater, sufficiently in advance, makes it possible to properly select bioreactor settings to obtain optimal process conditions. This paper presents the use of classification models to predict the variability of wastewater quality at...
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Mitigating Traffic Remapping Attacks in Autonomous Multi-hop Wireless Networks
PublikacjaMultihop wireless networks with autonomous nodes are susceptible to selfish traffic remapping attacks (TRAs). Nodes launching TRAs leverage the underlying channel access function to receive an unduly high Quality of Service (QoS) for packet flows traversing source-to-destination routes. TRAs are easy to execute, impossible to prevent, difficult to detect, and harmful to the QoS of honest nodes. Recognizing the need for providing...
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Comparison of Doppler Effect Estimation Methods for MFSK Transmission in Multipath Hydroacoustic Channel
PublikacjaUnderwater wireless communication remains a challenging topic, particularly for applications such as wreck penetration where multipath and Doppler effects are very intense. These effects are becoming even more difficult to mitigate for fast data transmission systems that utilize wideband signals. Due to the low propagation speed of acoustic wave in the water, there is a significant difference between the Doppler shift for lower...