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Circularly Polarized Antenna Array design with the Potential of Gain-Size Trade-off and Omnidirectional Radiation for Millimeter-Wave Small Base Station Applications
PublikacjaThis paper presents the design and validation of a slot-patch-hybrid circularly polarized antenna array for 28 GHz millimeter (mm) wave (mm-wave) applications. The proposed design has a simple geometry that facilitates the fabrication process, which is otherwise a challenging task due to the sub-mm dimensions of the circuit in the mm-wave band. In the proposed structure, aperture-coupled series slot-fed array is utilized to excite...
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Feedback Control of Doubly-Fed Generator Connected to Current Source Converter
PublikacjaDoubly-fed induction generator (DFIG) system supplied by current source converter (CSC) is considered in this article. The DFIG can work in two independent modes: AC grid connection and stand-alone mode. The DFIG is connected to the ac grid directly through its stator and the CSC links the rotor side. In this mode, the active and reactive powers of the DFIG must be controlled. This article proposes two control system structures...
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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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Acceleration of Electromagnetic Simulations on Reconfigurable FPGA Card
PublikacjaIn this contribution, the hardware acceleration of electromagnetic simulations on the reconfigurable field-programmable-gate-array (FPGA) card is presented. In the developed implementation of scientific computations, the matrix-assembly phase of the method of moments (MoM) is accelerated on the Xilinx Alveo U200 card. The computational method involves discretization of the frequency-domain mixed potential integral equation using...
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Prediction of the Mechanical Properties of P91 Steel by Means of Magneto-acoustic Emission and Acoustic Birefringence
PublikacjaThe paper describes an application of nondestructive volumetric magnetic and ultrasonic techniques for evaluation of the selected mechanical parameter variations of P91 steel having direct influence on its suitability for further use in critical components used in power plants. Two different types of deformation processes were carried out. First, a series of the P91 steel specimens was subjected to creep and second, one to plastic...
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Quality Evaluation of Speech Transmission via Two-way BPL-PLC Voice Communication System in an Underground Mine
PublikacjaIn order to design a stable and reliable voice communication system, it is essential to know how many resources are necessary for conveying quality content. These parameters may include objective quality of service (QoS) metrics, such as: available bandwidth, bit error rate (BER), delay, latency as well as subjective quality of experience (QoE) related to user expectations. QoE is expressed as clarity of speech and the ability...
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A dual-control strategy based on electrode material and electrolyte optimization to construct an asymmetric supercapacitor with high energy density
PublikacjaMetal-organic frames (MOFs) are regarded as excellent candidates for supercapacitors that have attracted much attention because of their diversity, adjustability and porosity. However, both poor structural stability in aqueous alkaline electrolytes and the low electrical conductivity of MOF materials constrain their practical implementation in supercapacitors. In this study, bimetallic CoNi-MOF were synthesized to enhance the electrical...
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SiC-based T-type modules for multi-pulse inverter with coupled inductors
PublikacjaThe paper presents SiC-based three-level T-type modules designed for a high-performance 30kVA DC/AC inverter operating at high frequency 85 kHz with low THD of the output voltage. This inverter system consists of two integrated parts. The first part is active and contains three parallelconnected three-phase T-type modules built with fast-switching SiC power transistors. The second, passive part of the system is a set of inductors...
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Contactless hearing aid designed for infants
PublikacjaIt is a well known fact that language development through home intervention for a hearing-impaired infant should start in the early months of a newborn baby's life. The aim of this paper is to present a concept of a contactless digital hearing aid designed especially for infants. In contrast to all typical wearable hearing aid solutions (ITC, ITE, BTE), the proposed device is mounted in the infant's bed with any parts of its set-up...
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Fracture surface topography measurements analysis of low-alloyed corrosion resistant steel after bending-torsion fatigue tests
PublikacjaIn this paper, an assessment of a topography measurement method for fracture surfaces of 10HNAP steel after bending-torsion fatigue tests was performed. Surface roughness was measured by using a non-contact Focus Variation Microscopy (FVM) technique in which the non-measured points (NMPs) and outliers (spikes) were removed by the application of general methods. The results revealed, that the optical measurement method introduced...
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Modelling and analysis of medium frequency transformers for power converters
PublikacjaThe evolutions in power systems and electric vehicles, related to the economic opportunities and the environmental issues, bring the need of high power galvanically isolated DC-DC converter. The medium frequency transformer (MFT) is one of its key components, enabled by the increasing switching frequency of modern power semiconductors like silicon carbide transistors or diodes. The increased operating frequency offers small...
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Dielectric Properties of BiNbO<sub>4</sub>-Based Ceramic-Polymer Composites with 0-3 Connectivity
PublikacjaIn the present study two-phase BiNbO4//PVDF composites with 0-3 connectivity were studied by impedance spectroscopy within the frequency range Δν=100Hz-1MHz at room temperature. Polyvinylidene fluoride (PVDF) acted as a matrix whereas bismuth niobate (BiNbO4) powder acted as a dispersed phase. The volume fraction of the ceramic phase was cV=2, 4, 6, 8, 10, 16 and 20vol%. Analysis of the impedance data registered for composites...
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Enhanced photocatalytic properties of lanthanide-TiO2 nanotubes: An experimental and theoretical study
PublikacjaA series of Er-, Yb-, Ho-, Tb-, Gd-, Pr-TiO2 nanotubes (RE-NTs) was prepared via an electrochemical method. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis absorption, scanning electron microscopy (SEM) and luminescent spectroscopy. The experiments demonstrated that toluene in the gas phase was successfully degraded under visible light (LEDs λmax = 465...
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Experimental Research on the Energy Efficiency of a Parallel Hybrid Drive for an Inland Ship
PublikacjaThe growing requirements for limiting the negative impact of all modes of transport on the natural environment mean that clean technologies are becoming more and more important. The global trend of e-mobility also applies to sea and inland water transport. This article presents the results of experimental tests carried out on a life-size, parallel diesel-electric hybrid propulsion system. The eciency of the propulsion system was...
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A distributed system for conducting chess games in parallel
PublikacjaThis paper proposes a distributed and scalable cloud based system designed to play chess games in parallel. Games can be played between chess engines alone or between clusters created by combined chess engines. The system has a built-in mechanism that compares engines, based on Elo ranking which finally presents the strength of each tested approach. If an approach needs more computational power, the design of the system allows...
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Assessment of the impact of jet impingement technique on the energy efficiency of air-cooled BIPV/T roof tile
PublikacjaThe paper concerns a numerical analysis of cooling of the hybrid photovoltaic (PV) modules dedicated to Building-Integrated Photovoltaic/Thermal (BIPV/T) systems. Attention was focused on the photovoltaic roof tiles, using a jet impingement technique, in which the intensification of heat transfer is ensured by streams of air hitting the heat exchange partition. A series of numerical simulations were carried out to assess an influence...
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Various cases of preservation and adaptive reuse Heritage Buildings in the Port of Gdynia
PublikacjaThe port of Gdynia contains a diverse range of heritage assets, starting with its spatial layout which is an urban concept designed in the first half of the 1920s. It is important to point out, this historically-shaped harbor space is preserved in its general idea and still functioning in port activities. Another significant element is the structural, technological solution which was the basis for constructing the entire port area...
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Influence of reactive oxygen species during deposition of iron oxide films by high power impulse magnetron sputtering.
PublikacjaIron oxide films were deposited using high power impulse magnetron sputtering (HiPIMS) of an iron cathode in an argon/oxygen gas mixture at different gas pressures (0.5~Pa, 1.5~Pa, and 5.0~Pa). The HiPIMS system was operated at a repetition frequency $f = 100$~Hz with a duty cycle of 1~\%. A main goal is a comparison of film growth during conventional and electron cyclotron wave resonance-assisted HiPIMS. The deposition plasma...
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Designing efficient A-D-A1-D-A type fullerene free acceptor molecules with enhanced power conversion efficiency for solar cell applications
PublikacjaThe achievement of highly efficient power conversion efficiency (PCE) is a big concern for non-fullerene organic solar cells (NF-OSCs) because PCE can depend on numerous variables. Here, new five novel acceptor molecules without fullerenes were developed and investigated using DFT (density functional theory) and TD-DFT (time dependent-density functional theory). Compared to the recently synthesized molecule (PZ-dIDTC6), the developed...
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CLEANING METHODS FOR DUST DEPOSITED ON THE FRONT COVER OF PHOTOVOLTAIC MODULE
PublikacjaPhotovoltaic modules are one of the renewable energy sources with great potential for application in various regions of the world as well as for different terrain. They are, however, sensitive to external factors, affecting the overall amount of energy generated, such as solar irradiance, shading effects and any form of soil build-up on the front glass cover of solar device. The latter issue happens over a course of weeks, months...
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Comparative study on total nitrogen prediction in wastewater treatment 1 plant and effect of various feature selection methods on machine learning algorithms performance
PublikacjaWastewater characteristics prediction in wastewater treatment plants (WWTPs) is valuable and can reduce the number of sampling, energy, and cost. Feature Selection (FS) methods are used in the pre-processing section for enhancing the model performance. This study aims to evaluate the effect of seven different FS methods (filter, wrapper, and embedded methods) on enhancing the prediction accuracy for total nitrogen (TN) in the WWTP...
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Change of reaction quotients for SOFC fueled by biogas mixture at 750 C
Dane BadawczeThe dataset contains the Change of reaction quotients for SOFC fueled by biogas mixture at 750 C (60:40 CH4:CO2). The outlet concentration of the gases from SOFC were measured using novel FTIR-based unit.
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A novel concept of negative CO2 emission power plant for utilization of sewage sludge
PublikacjaCarbon Capture and Storage (CSS) technology is considered an important “bridge technology”, allowing effective abatement of CO2 emissions for power units using fossil fuels. However, if biomass is used in a power plant, equipped with CCS system, negative CO2 emissions can be achieved. In practice, wide development of such technologies would enable not only reduction of CO2 emissions, but also reversal of the harm done so far. In...
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Effect of asymmetric fluid flow distribution on flow boiling in a microchannel heat sink – An experimental investigation
PublikacjaFlow boiling in microchannels is emerging as an exclusive cooling solution for miniaturized high-power electronic devices alongside having other high heat flux applications. Size miniaturization at microscale strangely increases heat transfer performance as well as flow boiling instabilities. Many flow boiling instabilities are interrelated and result from imperfect hydrodynamic conditions. One of such problems is flow maldistribution among...
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Solar radiation (PAR, UV-B and UV-A) reaching the sea surface - Gdańsk Deep (2001-2005)
Dane BadawczeSolar radiation reaching the sea surface was measured in spring (2001, 2003, 2005) and autumn (2002, 2004). For measurements of the photosynthetic active radiation - PAR (400-700 nm), the Ejkelkamp SKP 210 / I 0896 13595 sensor was used, the UV-B radiation (280-315 nm) was measured with the Ejkelkamp SKU 430 0497 14854 sensor, while UV-A (315- 380 nm)...
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Impact of Propeller Emergence on Hull, Propeller, Engine, and Fuel Consumption Performance in Regular Head Waves
PublikacjaIn this study, the impact of propeller emergence on the performance of a ship (speed), propeller (thrust, torque, and RPM), a diesel engine (torque and RPM) and fuel consumption are analysed under severe sea conditions. The goal is to describe the variation in the system variables and fuel consumption rather than analysing the motion of the ship or the phenomenon of propeller ventilation in itself. A mathematical model of the...
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Development of an Advanced Control Algorithm for DAB DC/DC Converters: Inrush Current Limitation and Enhanced Operation in Transient States.
PublikacjaThe publication addresses the dynamic state challenges encountered during development of a dual active bridge (DAB) converter within DC microgrid systems. The conventional startup method is identified as instigating a cascade of unfavorable outcomes, encompassing elevated starting current, transformer current asymmetry, DC voltage distortions, EMI and heightened thermal stress on semiconductor components. Additionally, it necessitates...
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Hybridized SVPWM Algorithm for Multilevel CHB Inverter With DC-Link Voltage Control Capability
PublikacjaThe deployment of a space vector pulsewidth modulation (SVPWM) scheme in controlling cascaded H-bridge multilevel inverter (CHB MLI) is quite challenging; especially, when a substantial number of output voltage levels are involved and the dc-link voltages are out of balance. In this article, a simple SVPWM algorithm for CHB MLI is proposed. In the proposed algorithm, all the H-bridges in an inverter phase are treated as a single...
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Synthesis, Molecular Structure, Anticancer Activity, and QSAR Study of N-(aryl/heteroaryl)-4-(1H-pyrrol-1-yl)Benzenesulfonamide Derivatives
PublikacjaA series of N-(aryl/heteroaryl)-4-(1H-pyrrol-1-yl)benzenesulfonamides were synthesized from 4-amino-N-(aryl/heteroaryl)benzenesulfonamides and 2,5-dimethoxytetrahydrofuran. All the synthesized compounds were evaluated for their anticancer activity on HeLa, HCT-116, and MCF-7 human tumor cell lines. Compound 28, bearing 8-quinolinyl moiety, exhibited the most potent anticancer activity against the HCT-116, MCF-7, and HeLa cell lines,...
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High load capacity spur gears with conchoidal path of contact
PublikacjaThe present study is devoted to investigation of spur gears with a conchoidal path of contact and a convex-convex contact between teeth. The load capacity and energy efficiency were evaluated using both theoretical and experimental approaches. The theoretical analysis showed that the conchoidal gear pairs are 5–21% stronger in terms of contact stress and have similar energy efficiency as compared to the involute gear pairs of the...
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Surface Dielectric Barrier Discharge Plasma Actuators
PublikacjaThis paper presents a part of the works conducted in the Plasmaero European project (task 1.1) on surface dielectric barrier discharge actuators applied to airflow control. The study is divided into several parts. In the first part, the goal is to enhance the electric wind produced by a typical single DBD actuator by optimization of the active electrode shape. For instance, the use of a thin wire instead of a plate air-exposed...
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Partially Isolated Multi-Active Bridge DC-DC Converter with Bidirectional EV Charging Ports
PublikacjaThere is a growing interest in multiport converters due to their ability to interconnect various energy sources and loads using reduced number of components. Regarding electric vehicle (EV) chargers connection, existing multiport solutions either lack scalability, featuring only one isolated charging port or the operation of ports depend on each other, complicating the converter control algorithm. This article proposes a partially...
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Performance of the domestic micro ORC equipped with the shell-and-tube condenser with minichannels
PublikacjaIn this paper, the original compact shell-and-tube heat exchanger with circular minichannels of in-house design and manufacturing is presented as the condenser for the domestic micro heat and power plant investigations as well as other future technical applications. The heat exchanger is equipped with turbulizing baffles inside the shell. The shell itself is made of a tubular sleeve having an inner diameter of 0.067 m and the length...
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Treatment of landfill leachate by constructed wetlands: three case studies
PublikacjaThe performance of three CW systems treating landfill leachate, two located in northern Poland (Szadółki near Gdańsk and Gatka near Miastko) and one in southern Sweden (Örebro), is discussed. The CWs differ in size, hydraulic regime, type of hydrophytic plants and type of leachate pre-treatment before discharging to the CW. The CW in Szadółki consists of two parallel beds with sub-surface, horizontal flow of leachate (HSSF) planted...
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A novel hybrid adaptive framework for support vector machine-based reliability analysis: A comparative study
PublikacjaThis study presents an innovative hybrid Adaptive Support Vector Machine - Monte Carlo Simulation (ASVM-MCS) framework for reliability analysis in complex engineering structures. These structures often involve highly nonlinear implicit functions, making traditional gradient-based first or second order reliability algorithms and Monte Carlo Simulation (MCS) time-consuming. The application of surrogate models has proven effective...
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Availability of UAV Fleet Evaluation Based on Multi-State System
PublikacjaUnmanned Aerial Vehicle (UAV) applications are extended extremely. Some applications need to use several UAVs for a general mission which can be considered a UAV fleet. One of the important characteristics for the evaluation of a UAV or UAV fleet is reliability. There are studies in which methods for analysis of their reliability are considered. Reliability analysis of UAV fleets is less frequently studied, although a single UAV...
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From Data to Decision: Interpretable Machine Learning for Predicting Flood Susceptibility in Gdańsk, Poland
PublikacjaFlood susceptibility prediction is complex due to the multifaceted interactions among hydrological, meteorological, and urbanisation factors, further exacerbated by climate change. This study addresses these complexities by investigating flood susceptibility in rapidly urbanising regions prone to extreme weather events, focusing on Gdańsk, Poland. Three popular ML techniques, Support Vector Machine (SVM), Random Forest (RF), and...
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Blowing Kinetics, Pressure Resistance, Thermal Stability, and Relaxation of the Amorphous Phase of the PET Container in the SBM Process with Hot and Cold Mold. Part II: Statistical Analysis and Interpretation of Tests
PublikacjaThe technology of filling drinks without preservatives (such as fresh juices, iced tea drinks, and vitaminized drinks) is carried out using hot filling. Mainly due to the production costs and lower carbon footprint, polyethylene terephthalate (PET) bottles are increasingly used in this technology. In this paper, the main aim is to describe and interpret the results of statistical analysis of the influence of the temperature of...
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Blowing Kinetics, Pressure Resistance, Thermal Stability, and Relaxation of the Amorphous Phase of the PET Container in the SBM Process with Hot and Cold Mold. Part I: Research Methodology and Results
PublikacjaThe technology of filling drinks without preservatives (such as fresh juices, iced tea drinks, vitaminized drinks) is carried out using hot filling. Mainly due to the production costs and lower carbon footprint, polyethylene terephthalate bottles, commonly called PET, are increasingly used in this technology. In this paper, the main aim is to describe the statistical analysis methodology of the influence of the temperature of the...
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Nutritional and Pharmaceutical Properties of Bioactive Compounds in Organic and Conventional Growing Kiwifruit
PublikacjaThe bioactivity of two kiwifruit’s cultivars growing under organic and conventional conditions were studied and compared. The bioactive compounds were extracted with water and ethanol using similar conditions which are applied in pharmaceutical applications and for daily fruit consumption such as tea drink. Antioxidant radical scavenging assays [ferric-reducing/antioxidant power (FRAP); cupric reducing antioxidant capacity (CUPRAC);...
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Active IR-Thermal Imaging in Medicine
PublikacjaIn this paper we summarize results of several research projects devoted to development of new diagnostic methods and procedures based on quantitative infrared thermography in medical applications. First, basics of active dynamic thermography are presented. Described are both, instrumentation and software comprising measurement procedures including collection of series of IR-images after external excitation, data treatment with...
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Modelling and simulation of GPU processing in the MERPSYS environment
PublikacjaIn this work, we evaluate an analytical GPU performance model based on Little's law, that expresses the kernel execution time in terms of latency bound, throughput bound, and achieved occupancy. We then combine it with the results of several research papers, introduce equations for data transfer time estimation, and finally incorporate it into the MERPSYS framework, which is a general-purpose simulator for parallel and distributed...
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Theoretical designing of selenium heterocyclic non-fullerene acceptors with enhanced power conversion efficiency for organic solar cells: a DFT/TD-DFT-based prediction and understanding
PublikacjaIn this study, we have designed and explored a new series of non-fullerene acceptors for possible applications in organic solar cells. We have designed four molecules named as APH1 to APH4 after end-capped modification of recently synthesized Y6-Se-4Cl molecule. Density functional theory and time dependent-density functional theory have been employed for computing geometric and photovoltaic parameters of the designed molecules....
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Water-mediated influence of a crowded environment on internal vibrations of a protein molecule
PublikacjaThe influence of crowding on the protein inner dynamics is examined by putting a single protein molecule close to one or two neighboring protein molecules. The presence of additional molecules influences the amplitudes of protein fluctuations. Also, a weak dynamical coupling of collective velocities of surface atoms of proteins separated by a layer of water is detected. The possible mechanisms of these phenomena are described....
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Collision Risk-Informed Weather Routing for Sailboats
PublikacjaSelected COLREG rules, good seamanship and sheer common sense indicate that it is in a sailboat's interest to follow collision-free routes without relying on large power-driven ships to give way. Until now, however, no method has integrated a sailboat's weather routing with collision risk monitoring and collision avoidance. Therefore, a new deterministic approach to combine the above features within one method is introduced here....
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Detection of Anomalies in the Operation of a Road Lighting System Based on Data from Smart Electricity Meters
PublikacjaSmart meters in road lighting systems create new opportunities for automatic diagnostics of undesirable phenomena such as lamp failures, schedule deviations, or energy theft from the power grid. Such a solution fits into the smart cities concept, where an adaptive lighting system creates new challenges with respect to the monitoring function. This article presents research results indicating the practical feasibility of real‐time...
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Behaviour of Asymmetric Structure with Base Isolation Made of Polymeric Bearings
PublikacjaEarthquake-induced ground motions are the most severe and unpredictable threats to the structures all around the world. Seismic excitations cause a lot of damage in a wide variety of ways, leaving thousands of casualties in their wake. Due to randomness of earthquake occurrence, lack of visible causes and their power of destructiveness, structural engineers need to develop new technical solutions and protection systems against...
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Fast GC as a useful tool for authenticity assessment of kiwifruit
PublikacjaKiwifruit is one of the healthiest fruits due to its high content of biologically active substances and nutrients. The most popular species of Actinidia (kiwifruit) are the Actinidia deliciosa fruits called kiwi and Actinidia chinensis commonly called golden kiwi, while the lesser known species is Actinidia arguta known as mini kiwi. Bioactivities and nutrients of Actinidia are influenced by species and cultivars. It is very important...
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Information retrieval with semantic memory model
PublikacjaPsycholinguistic theories of semantic memory form the basis of understanding of natural language concepts. These theories are used here as an inspiration for implementing a computational model of semantic memory in the form of semantic network. Combining this network with a vector-based object-relation-feature value representation of concepts that includes also weights for confidence and support, allows for recognition of concepts...
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Novel 2-alkythio-4-chloro-N-[imino(heteroaryl)methyl]benzenesulfonamide Derivatives: Synthesis, Molecular Structure, Anticancer Activity and Metabolic Stability
PublikacjaA series of novel 2-alkythio-4-chloro-N-[imino-(heteroaryl)methyl]benzenesulfonamide derivatives, 8–24, were synthesized in the reaction of the N-(benzenesulfonyl)cyanamide potassium salts 1–7 with the appropriate mercaptoheterocycles. All the synthesized compounds were evaluated for their anticancer activity in HeLa, HCT-116 and MCF-7 cell lines. The most promising compounds, 11–13, molecular hybrids containing benzenesulfonamide...