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Search results for: 3d printing , additive manufacturing , cubesat , fifth-generation (5 g) communication , internet-of-things , millimeter-wave antenna , passive multi-beam antennas , reconfigurable antennas , switched-beam antennas
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Truss imperfections in the design of bar and diaphragm bracing systems
PublicationIn the article three variants of roof bracing were considered: bar bracing, diaphragm bracing and the combination of bar and diaphragm bracing. Different analytical and numerical ways of taking into account the imperfections of the truss girder were compared. The entire 3D model of the roof (shell and beam elements with the eccentricities taken into account) was analysed numerically. Selected stressed-skin aspects were considered....
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Two- and three-dimensional elastic networks with rigid junctions: modeling within the theory of micropolar shells and solids
PublicationFor two- and three-dimensional elastic structures made of families of flexible elastic fibers undergoing finite deformations, we propose homogenized models within the micropolar elasticity. Here we restrict ourselves to networks with rigid connections between fibers. In other words, we assume that the fibers keep their orthogonality during deformation. Starting from a fiber as the basic structured element modeled by the Cosserat...
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Performance Analysis of Convolutional Neural Networks on Embedded Systems
PublicationMachine learning is no longer confined to cloud and high-end server systems and has been successfully deployed on devices that are part of Internet of Things. This paper presents the analysis of performance of convolutional neural networks deployed on an ARM microcontroller. Inference time is measured for different core frequencies, with and without DSP instructions and disabled access to cache. Networks use both real-valued and...
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Femtosecond Er-doped fiber laser source tunable from 872 to 1075 nm for two-photon vision studies in humans
PublicationWe report the development of a widely-tunable femtosecond fiber laser system and its application for two-photon vision studies. The source is based on an Er-doped fiber laser with spectral shift up to 2150 nm, followed by a second harmonic generation module to generate a frequency-doubled beam tunable from 872 to 1075 nm. The source delivers sub-230 fs pulses with nearly-constant duration over the entire tuning range, with output...
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A concept of measurement system based on the Z-Wave standard
PublicationIn the paper a new concept of measurement system based on the Z-Wave standard is presented. This standard is dedicated to use mainly in home automation systems, but its properties enable to use it in dispersed measurement systems and support wireless communication between measurement nodes in a mesh-type network. In the paper basic metrological aspects of the Z-Wave standard and an example of impedance measurement system are discussed.
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Recent Advances in Loop Heat Pipes with Flat Evaporator
PublicationThe focus of this review is to present the current advances in Loop Heat Pipes (LHP) with flat evaporators, which address the current challenges to the wide implementation of the technology. A recent advance in LHP is the design of flat-shaped evaporators, which is better suited to the geometry of discretely mounted electronics components (microprocessors) and therefore negate the need for an additional transfer surface (saddle)...
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5G/6G optical fronthaul modeling: cost and energy consumption assessment
PublicationIn fifth generation (5G) and the future beyond 5G (6G) radio access networks (RANs), the cost of fronthaul deployment is a main challenge for mobile network operators. Depending on different constraints, there are various solutions to deploy an efficient fronthaul. Fiber-optic-based fronthaul offers long-term support with regard to a rapid increase in capacity demands. When fiber connections, either point-to-point (P2P) or point-to-multipoint...
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Low-energy positron scattering from gas-phase pyrimidine: A quantum treatment of the dynamics and a comparison with experiments
PublicationWe are reporting detailed quantum scattering calculations that describe the diffusion of a beam of low-energy positrons interacting with the pyrimidine target as a gas-phase partner. The calculations have employed an essentially ab initio model for the short-range correlation interaction and for the electrostatic interaction of an impinging positron and the electron+nuclear structure of the target molecule at its equilibrium geometry.
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Evaluation of Response Amplitude Operator of Ship Roll Motions Based on the Experiments in White Noise Waves
PublicationEvaluation of the response amplitude operator (RAO) function for ship wave frequency motions by means of scale model tests in regular waves is a standard procedure conducted by hydrodynamic model testing institutions. The resulting RAO function allows for evaluating sufficiently reliable seakeeping predictions for low to moderate sea states. However, for standard hull forms, correct prediction of roll motion in irregular wave (and...
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Experience-Based Cognition for Driving Behavioral Fingerprint Extraction
PublicationABSTRACT With the rapid progress of information technologies, cars have been made increasingly intelligent. This allows cars to act as cognitive agents, i.e., to acquire knowledge and understanding of the driving habits and behavioral characteristics of drivers (i.e., driving behavioral fingerprint) through experience. Such knowledge can be then reused to facilitate the interaction between a car and its driver, and to develop better and...
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seafloor characterisation combined approach using multibeam sonar echo signal processing and image analysis
PublicationThe authors propose the approach to seafloor characterisation which relies on the combined, concurrent use of two different techniques: (i) multibeam sonar image analysis and (ii) multibeam seabed echoes processing. The first technique is based on constructing the grey-level sonar images of the seabed extracted from the echoes received in the consecutive soundings. Then, the set of parameters describing the local region of sonar...
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Effects of laser pulse duration in two-photon vision threshold measurements
PublicationPulsed near-infrared (NIR) light sources can be successfully applied for both imaging and functional testing of the human eye, as published recently1. These two groups of applications have different requirements. For imaging applications, the most preferable is invisible scanning beam while efficiently visible stimulating beam is preferable for functional testing applications. The functional testing of human eye using NIR laser...
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Friction-Induced Oscillations of a Non-Asbestos Organic Pin Sliding on a Steel Disc
PublicationFriction-induced oscillations result in deterioration of performance of disc brakes and are generally undesired. We conduct experimental study of friction-induced oscillations in a non-asbestos organic material / steel pair used in disc brakes of motor vehicles. The tests are done by use of a pin-on-disc machine which has the pin sample supported on a deformable beam. The adjustable friction parameters are the disc velocity, contact...
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Experimental tests of lintel hybrid beams
PublicationThe results of experimental tests of lintel hybrid beams made of air concrete and prestressed concrete were presented in paper. Blocks of air concrete was a protective element for the construction one. The length of hybrid beams was 3.0 m, while total height 27 cm. It was assumed that hybrid beams will work in the simply-supported scheme (with a 10 cm support) loaded uniformly over the entire length. The object of the tests were...
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Methodology for Processing of 3D Multibeam Sonar Big Data for Comparative Navigation
PublicationAutonomous navigation is an important task for unmanned vehicles operating both on the surface and underwater. A sophisticated solution for autonomous non-global navigational satellite system navigation is comparative (terrain reference) navigation. We present a method for fast processing of 3D multibeam sonar data to make depth area comparable with depth areas from bathymetric electronic navigational charts as source maps during...
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Active Suppression of Nonstationary Narrowband Acoustic Disturbances
PublicationIn this chapter, a new approach to active narrowband noise control is presented. Narrowband acoustic noise may be generated, among others, by rotating parts of electro-mechanical devices, such as motors, turbines, compressors, or fans. Active noise control involves the generation of “antinoise”, i.e., the generation of a sound that has the same amplitude, but the opposite phase, as the unwanted noise, which causes them to interfere...
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Evaluation of citric acid corrosion inhibition efficiency and passivation kinetics for aluminium alloys in alkaline media by means of dynamic impedance monitoring
PublicationA novel approach is proposed for constructing the adsorption isotherm in corrosion studies, based on a well-known interaction between citric acid and aluminium in alkaline electrolytes. Our approach utilizes the instantaneous impedance measurements via Dynamic Electrochemical Impedance Spectroscopy in galvanostatic mode (g-DEIS). Unlike other common tools, g-DEIS delivers exact information about the concentration required for full...
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The Indonesian economy in 2005: An analysis using the input-output approach
PublicationThis study aims to analyze the economic conditions of Indonesia in 2005. This study employs Input-Output (IO) analysis as an analysis instrument. The data of this study is the Indonesian IO table for 2005. Thus, the Indonesian economy is represented by Indonesian industrial sectors mentioned in the data. There are nine industries used in the present study, namely (1) agriculture, livestock, forestry, and fishery, (2) mining and...
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Design optimization of novel compact circular polarization antenna
PublicationThe paper describes a structure and a design optimization procedure of a miniaturized circular polarization antenna with elliptical ground plane slots and feed line with stepped-impedance stubs. Constrained optimization of all antenna parameters is executed in order to explicitly reduce the antenna size while maintaining required impedance axial ratio bandwidth of 5 GHz to 7 GHz at the same time. The size of the optimized antenna...
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Experimental Designs of Mass Customized Passive Single-family Houses - Prospects and Limitations
PublicationAbstract The article deals with case studies of selected architectural designs of the past fifteen years the authors of which intended to rethink both the typology and the means of constructing single family houses. The analysis covers contemporary design issues such as variation, curvilinearity, customization, digital manufacturing and ecological concerns. The purpose behind the research was to establish in what way new design...
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Application of 3D- printed hydrogels in wound healing and regenerative medicine
PublicationHydrogels are three-dimensional polymer networks with hydrophilic properties. The modifiable properties of hydrogels and the structure resembling living tissue allow their versatile application. Therefore, increasing attention is focused on the use of hydrogels as bioinks for three-dimensional (3D) printing in tissue engineering. Bioprinting involves the fabrication of complex structures from several types of materials, cells,...
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Shallow Water Experiment of OFDM Underwater Acoustic Communications
PublicationThe large variability of communication properties of underwater acoustic channels, and especially the strongly varying instantaneous conditions in shallow waters, is a challenge for the designers of underwater acoustic communication (UAC) systems. The use of phase modulated signals does not allow reliable data transmission through such a tough communication channel. However, orthogonal frequency-division multiplexing (OFDM), being...
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Interdependence between Power Grids and Communication Networks: A Resilience Perspective
PublicationPower network resilience is increasingly dependent on communication networks. Besides traditional generation, power networks need to accommodate increasingly high penetration levels of dispersed micro generation, mostly based on renewable sources, and increasing and challenging demand, such as electric vehicles. At the same time the deployment of enabling technologies throughout the power grid makes available new demand resources...
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Design and optimization of a novel compact broadband linearly/circularly polarized wide-slot antenna for WLAN and Wi-MAX applications
PublicationA novel topologically modified structure of a compact low profile wide-slot antenna for broadband applications is presented. The antenna comprises a modified E-shaped slot with unequal arm lengths in the ground plane, and a parasitic quasi-rectangular loop placed coplanar with the feedline. For exciting orthogonal modes with equal amplitude, a single-point feeding technique with an asymmetrical geometry of the coplanar waveguide...
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Multi-state multi-reference Møller-Plesset second-order perturbation theory for molecular calculations
PublicationThis work presents multi‐state multi‐reference Møller–Plesset second‐order perturbation theory as a variant of multi‐reference perturbation theory to treat electron correlation in molecules. An effective Hamiltonian is constructed from the first‐order wave operator to treat several strongly interacting electronic states simultaneously. The wave operator is obtained by solving the generalized Bloch equation within the first‐order...
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Control design for slow speed positioning
PublicationThe problem under study is a synthesis of position and heading control system for low frequency model of surface vessel described by 3 DOF mathematical model. The recursive vectorial backstepping control design was used to keep fixed position and heading in presence of wave disturbances. The controller has been simulated on computer model of scaled supply vessel. It has been assumed that the actuators produce generalized forces...
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On local buckling of cold-formed channel members
PublicationThe paper deals with local buckling of the compressed flanges of cold-formed thin-walled channel beams subjected to pure bending or axially compressed columns. Arbitrarily shaped flanges of open cross-sections and the web-flange interactions are taken into account. Buckling deformation of a beam flange is described by displacement related to torsion of the flange about the line of its connection with the web. Total potential energy...
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BASICS OF THE MANAGEMENT SYSTEM FOR TRANSFORMATIONS OF PRODUCTION PLANNING AND CONTROL PROCESSES
PublicationIntensive development of technologies, in particular of the spinotronics, nanotechnology, robotics, and ICT, shapes the new generation production systems. Their distinctive feature is the flexi-bility associated with production intelligence. It is required from all processes, including the production planning and control processes (PPCP). The article is of conceptual character. It was prepared based on literature research. It encompasses...
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A Note on Reduced Strain Gradient Elasticity
PublicationWe discuss the particular class of strain-gradient elastic material models which we called the reduced or degenerated strain-gradient elasticity. For this class the strain energy density depends on functions which have different differential properties in different spatial directions. As an example of such media we consider the continual models of pantographic beam lattices and smectic and columnar liquid crystals.
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Modelling of Geared Multi-Rotor System
PublicationIn the paper the method of modelling a speed-varying geared rotor system is presented. The proposed approach enables us to obtain an accurate low-order lumped parameter representation of the investigated system. The final model consists of reduced modal models of an undamped beam/torsional shaft system as well as a spatially lumped model of other linear and nonlinear phenomena including gear mesh interaction.
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Wpływ ukształtowania zbrojenia na zarysowanie i nośność żelbetowego węzła tarczowego ze wspornikiem
PublicationPraca ma charakter eksperymentalno-teoretyczny i dotyczy zagadnień związanych z żelbetowymi tarczami pracującymi w przestrzennym układzie konstrukcji budynków. Celem niniejszej dysertacji było określenie wpływu głównych parametrów jakimi są sposób ukształtowania zbrojenia i smukłość ścinania na zarysowanie i nośność żelbetowego przestrzennego węzła tarczowego ze wspornikiem. Na podstawie aktualnego stanu wiedzy, opracowano program...
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Possibilities of applying standard tools of promotion in place marketing
PublicationThe purpose of this article is to present the tools of promotion that can be used by local government units in the developing and implementing of marketing strategies. The article evaluates a set of four basic tools of promotion comprising advertising, public relations and publicity, sales promotion and personal selling. This group was supplemented by direct marketing, presented from the point of view of communication via the Internet.
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Computational fluid dynamics simulation of heat transfer from densely packed gold nanoparticles to isotropic media
PublicationThis work aims to determine and compare heat generation and propagation of densely packed gold nanoparticles (Au NPs) induced by a resonant laser beam (532 nm) according to the Mie theory. The heat flux propagation is transferred into the materials, which here are: silica glass; soda-lime-silica glass; borosilicate glass; polymethyl methacrylate (PMMA); polycarbonate (PC); and polydimetylosiloxane (PDMS). This analysis aims to...
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THE APPLICATION EFFECTS OF CONTINUOUS SATELLITE MEASUREMENTS OF RAILWAY LINES
PublicationThe paper presents results of satel lite surveying of the railway's rout es, which have been conducted just after starting in Poland (in 2008) the Active Geodesy Network ASG-EU POS. Afterwards it was possible to effectively utilize the GNSS survey ing results for the inventory of the (exploring) railways in service. Already at the beginning of 2009, the research team from Gdansk University of Technology and Naval Academy in Gdynia,...
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Quality of Service in ASON/GMPLS Network with Hierarchical Control Plane Structure
PublicationThe paper presents the problem of quality of service for hierarchical control plane structure of Automatically Switched Optical Network (ASON) utilizing Generalized Multi-Protocol Label Switching (GMPLS). The approach is implemented to control the multidomain network with required quality of service, in a use case of incomplete domain network information. The authors examine different factors, including resource reservation algorithms...
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Performance Evaluation of Control Plane Functions in ASON/GMPLS Architecture
PublicationIt is assumed that demands of information society could be satisfied by architecture ASON/GMPLS comprehended as Automatically Switched Optical Network (ASON) with Generalized Multi-Protocol Label Switching (GMPLS) protocols. Introduction this solution must be preceded performance evaluation to guarantee society expectations. Practical realization is expensive and simulations models are necessary to examine standardized propositions....
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Practical Trial for Low-Energy Effective Jamming on Private Networks With 5G-NR and NB-IoT Radio Interfaces
PublicationFourth-generation (4G) mobile networks are successively replaced by fifth-generation (5G) ones, based on the new releases of the 3rd Generation Partnership Project (3GPP) standard. 5G generation is dedicated to civilian users and the conducted analytical work shows that it has numerous technological gaps that prevent its direct implementation in military communications systems. However, the recent armed world conflicts showed that...
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The shallow sea experiment with usage of linear hydrophone array
PublicationPurpose of this article is to present designed and made linear hydrophone array and the results obtained during in situ trails on Gulf of Gdańsk. The measuring system allowed to localize hydrophones in the selected points and perform measurements in both the horizontal antenna positioning and vertical. Made in this way recordings allow creating accurate 3D imaging of sound intensity/propagation. During research three floating objects...
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Control System Design for Dynamic Positioning using Vectorial Backstepping
PublicationThe problem of synthesis a dynamic positioning system for low frequency model of surface vessel was considered in this paper. The recursive vectorial backstepping control design was used to keep a fixed position and heading in presence of wave disturbances. The passive observer was introduced to smooth the measurements and to estimate the velocities needed for the control algorithm. The computer simulation results were given to...
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Effect of surface on the flexomagnetic response of ferroic composite nanostructures; nonlinear bending analysis
PublicationOur analysis incorporates the geometrically nonlinear bending of the Euler-Bernoulli ferromagnetic nanobeam accounting for a size-dependent model through assuming surface effects. In the framework of the flexomagnetic phenomenon, the large deflections are investigated referring to von-Kármán nonlinearity. Employing the nonlocal effects of stress coupled to the gradient of strain generates a scale-dependent Hookean stress-strain...
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Surface effects of network materials based on strain gradient homogenized media
PublicationThe asymptotic homogenization of periodic network materials modeled as beam networks is pursued in this contribution, accounting for surface effects arising from the presence of a thin coating on the surface of the structural beam elements of the network. Cauchy and second gradient effective continua are considered and enhanced by the consideration of surface effects. The asymptotic homogenization technique is here extended to...
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Influence of the internet and electronic commerce growth on polish small and medium enterprises. PODAĆ POLSKI TYTUŁ.
PublicationTechnological development in communication creates new possibilities for commercial activity . Each new medium was changing business processes . Internet does the same - implies rapid changes in every stage of commercial activity.The aim of this paper is to show that the Internet and Electronic Commerce are influencing the Small and Medium Enterprises (SMEs) development in Poland. For achieving this another issue had to be under...
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Interval incidence coloring of subcubic graphs
PublicationIn this paper we study the problem of interval incidence coloring of subcubic graphs. In [14] the authors proved that the interval incidence 4-coloring problem is polynomially solvable and the interval incidence 5-coloring problem is N P-complete, and they asked if χii(G) ≤ 2∆(G) holds for an arbitrary graph G. In this paper, we prove that an interval incidence 6-coloring always exists for any subcubic graph G with ∆(G) = 3.
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BTEX concentration levels in urban air in the area of the Tri-City agglomeration (Gdansk, Gdynia, Sopot), Poland
PublicationThe paper presents and discusses the results of atmospheric air quality research conducted in 2012 with reference to the level of BTEX compounds in the Tri-City agglomeration—Gdansk, Gdynia, and Sopot (northern Poland). At the stage of BTEX sampling from the ambient air, Radiello® diffusive passive samplers were applied. The annual time-weighted average concentrations for benzene, toluene, ethylbenzene, and xylenes (BTEX) in the...
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Implementation of DIFAR Processing in ASW Dipping Sonar
PublicationThis paper presents the implementation of the signal processing algorithm used by buoy DIFAR (Directional Frequency Analysis and Recording), that is fully operational on Polish Navy anti-submarine warfare (ASW) helicopters and ships, applied to dipping sonars for detection and tracking of submarines. The development of the DSP algorithms was a part of the modernization of sonars conducted at the Gdansk University of Technology....
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Low-Cost Unattended Design of Miniaturized 4 × 4 Butler Matrices with Nonstandard Phase Differences
PublicationDesign of Butler matrices dedicated to Internet of Things and 5th generation (5G) mobile systems—where small size and high performance are of primary concern—is a challenging task that often exceeds capabilities of conventional techniques. Lack of appropriate, unified design approaches is a serious bottleneck for the development of Butler structures for contemporary applications. In this work, a low-cost bottom-up procedure for...
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Composite Beams with glass and reinforced or prestressed concrete - early stage of a theorethical and experimental analysis of a shear zone
PublicationThe aim of this article is to present a forgoing preparation for a theoretical and experimental analysis of a shear zone of a composite beams with glass and reinforced or prestressed concrete. Authors present their current knowledge, achievements and predicted challenges in later stages of the research. Properties of component materials are presented in the context of compensating weaknesses of one material with strengths of the...
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Benchmarking Scalability and Security Configuration Impact for A Distributed Sensors-Server IOT Use Case
PublicationInternet of Things has been getting more and more attention and found numerous practical applications. Especially important in this context are performance, security and ability to cope with failures. Especially crucial is to find good trade-off between these. In this article we present results of practical tests with multiple clients representing sensors sending notifications to an IoT middleware – DeviceHive. We investigate performance...
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Total domination in versus paired-domination in regular graphs
PublicationA subset S of vertices of a graph G is a dominating set of G if every vertex not in S has a neighbor in S, while S is a total dominating set of G if every vertex has a neighbor in S. If S is a dominating set with the additional property that the subgraph induced by S contains a perfect matching, then S is a paired-dominating set. The domination number, denoted γ(G), is the minimum cardinality of a dominating set of G, while the...
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Microfluidic SIW-Based Tunable Self-Diplexing Antenna for Sub-6 GHz Band Applications
PublicationThis work introduces a novel frequency tunable self-diplexing antenna (SDA) design based on substrate integrated waveguide (SIW) technology. A modified A-shaped slot is employed on the cavity’s top plane, which is excited by two independent 50 Ω microstrip feed lines to operate at each resonant frequency. The frequency flexibility of the proposed antenna allows for fine-tuning at each resonance frequency. The frequency flexibility...