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Search results for: RADIO CHANNEL MEASUREMENTS
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Assessment of Wide-Sense Stationarity of an Underwater Acoustic Channel Based on a Pseudo-Random Binary Sequence Probe Signal
PublicationThe performances of Underwater Acoustic Communication (UAC) systems are strongly related to the specific propagation conditions of the underwater channel. Designing the physical layer of a reliable data transmission system requires a knowledge of channel characteristics in terms of the specific parameters of the stochastic model. The Wide-Sense Stationary Uncorrelated Scattering (WSSUS) assumption simplifies the stochastic description...
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Implementacja odbiornika RAKE w technologii SDR (Software Defined Radio)
PublicationRóżnorodność standardów systemów radiokomunikacyjnych, w tym telefonii komórkowej i bezprzewodowej, przy dużej ruchliwości ich abonentów, powoduje, że niezbędne jest skonstruowanie wielosystemowego terminala ruchomego, mającego techniczne możliwości współpracy z systemami radiokomunikacyjnymi działającymi w różnych standardach. W ten sposób zrodziła się idea radia definiowanego programowego SDR (Software Define Radio), bazująca...
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Spectrum Sensing Based on Hybrid Spectrum Handoff in Cognitive Radio Networks
PublicationThe rapid advancement of wireless communication combined with insufficient spectrum exploitation opens the door for the expansion of novel wireless services. Cognitive radio network (CRN) technology makes it possible to periodically access the open spectrum bands, which in turn improves the effectiveness of CRNs. Spectrum sensing (SS), which allows unauthorized users to locate open spectrum bands, plays a fundamental part in CRNs....
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A Method for Underwater Wireless Data Transmission in a Hydroacoustic Channel under NLOS Conditions
PublicationWireless data transmission in the hydroacoustic channel under non-line-of-sight (NLOS) propagation conditions, for example, during a wreck penetration, is difficult to implement reliably. This is mostly due to the multipath propagation, which causes a reduction in the quality of data reception. Therefore, in this work an attempt has been made to develop a reliable method of wireless underwater communication test it under the NLOS...
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Stability and limit load analysis of a cold-formed channel section column
PublicationThe paper presents stability and limit load analysis of a steel column 1440 mm high of a cold-formed channel section, subjected to a combination of compression and bending. Experimental results were compared to the resistance of a code procedure and to the outcome of numerical non-linear analysis. Comparison was made of numerical solutions by means of static (Riks) and dynamic (Explicit and Implicit) methods. Perfectly elastic...
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Probe signal processing for channel estimation in underwater acoustic communication system
PublicationUnderwater acoustic communication channels are characterized by a large variety of propagation conditions. Designing a reliable communication system requires knowledge of the transmission parameters of the channel, namely multipath delay spread, Doppler spread, coherence time, and coherence bandwidth. However, the possibilities of its estimation in a realtime underwater communication system are limited, mainly due to the computational...
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Overview of Fading Channel Modeling
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Improvement of impulse radio electromagnetic compatibility
PublicationPublikacja zawiera opis jednej z możliwych technik modyfikacji widma sygnału ultraszerokopasmowego radia impulsowego na przykładzie standardu IEEE 802.15.4a, opartą o zmianę struktury sekwencji generowanych impulsów o bardzo krótkim czasie trwania. Technika ta może zmniejszyć ryzyko wzajemnych zakłóceń pomiędzy nowymi urządzeniami ultraszerkopasmowymi a istniejącymi urządzeniami radiokomunikacji wąskopasmowej
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Measurements and Measurement Systems [WIMiO][2023/24]
e-Learning Courses -
Optoelectronic device for hematocrit measurements
PublicationAn optoelectronic system for measurements of hematocrit level (HCT) in the whole human blood is presented. Proposed system integrates a dedicated optoelectronic sensor, a microcontroller and a small LCD display in a low cost, battery-powered, handheld device. Chosen method for determining blood hematocrit level is based on optical properties of whole blood in visible and NIR wavelength range. Measurements with the use of proposed...
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Shaping the New Vistula Spit Channel: Political, Economic, and Environmental Aspects
PublicationIn September 2022, the new shipping channel in Poland was opened for service. It connects the Port of Elbląg and the Gdańsk Bay in Poland, cutting through the Vistula Spit and the Vistula Lagoon. It was intended to enable direct access to the Baltic Sea from the Port of Elbląg without crossing Russian territory. Originally conceptualized decades ago, it has taken its final shape only recently. Its construction was associated with...
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Channel Blockage and Flow Maldistribution during Unsteady Flow in a Model Microchannel Plate heat Exchanger
PublicationThis paper describes the problem of channel blockage as a result of flow maldistribution between the channels of a model mini channel plate heat exchanger consisting of one pass on each leg. Each leg of the heat exchanger contains 51 parallel and rectangular minichannels of four hydraulic diameters namely 461 μm, 571 μm, 750 μm and 823 μm. In addition, a more complex geometry has been investigated where for the sake of breaking...
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Bandwidth Dependence of the Propagation Channel in Circular Metallic BAN Environments
PublicationIn this paper, the bandwidth dependence of the propagation channel for Body Area Networks (BANs) in circular metallic environments is addressed and models are proposed to evaluate the appropriate short-term fading margins that should be considered as a function of the system bandwidth. The deployment of BANs in metallic indoor environments, such as ships, factories, warehouses and other similar environments, involves additional...
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Architecture of security and application layer structure of radio system for monitoring and acquisition of data from traffic enforcement cameras
PublicationThe study presents architecture of security and application layer structure of Radio System for Monitoring and Acquisition of Data from Traffic Enforcement Cameras. It also provides general assumptions concerning the range of the system as well as its modules and application components.
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Impulse Impedance Measurements of Lightning Protection Earthings
PublicationLightning protection earthing systems should be tested at currents with time parameters similar to those of lightnings. A method and definition of a measured value of impulse impedance are introduced. The impulse impedance was determined by a quotient of voltage drop on the tested earthing to a value of current in measure circuit. The usefulness of the impulse method for lightning protection evaluation is tested on radio base stations...
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Measurements of the Hydraulic Fluids Compressibility
PublicationPerformance of the hydrostatic high-pressure drive systems is affected by the changes of working fluid’s volume. Presence of air bubbles in the fluid cause this problem to be even more serious. To study this phenomenon precise measurements of fluid’s bulk modulus are necessary. Differ-ent measurement methods are applied, but they are either limited to low pressure range or give inaccurate results. To solve the problem the new...
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Reliable OFDM Data Transmission with Pilot Tones and Error-Correction Coding in Shallow Underwater Acoustic Channel
PublicationThe performance of Underwater Acoustic Communication (UAC) systems are strongly related to the specific propagation conditions of the underwater channel. Horizontal, shallow-water channels are characterised by extremely disadvantageous transmission properties, due to strong multipath propagation and refraction phenomena. The paper presents the results of communication tests performed during a shallow, inland-water experiment with...
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A Study of Mutual Coupling Suppression between Two Closely Spaced Planar Monopole Antenna Elements for 5G New Radio Massive MIMO System Applications
Publication5G NR (new radio) introduces the concept of massive MIMO (multiple-input-multiple-output) technology, in which a larger number of antenna arrays are installed on the transceiver. Due to the increased number of antenna elements allocated close to each other (approximately at half-wavelength distance), mutual coupling becomes a serious problem leading to performance degradation of the MIMO communication system. In this communication,...
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Radio system for monitoring and acquisition of data from traffic enforcement cameras - features and assumptions of the system
PublicationThe study presents the architecture and selected functional assumptions of Radio System for Monitoring and Acquisition of Data from Traffic Enforcement Cameras (RSMAD). Ultimately, the system will be used for transmission and archiving image data of traffic offenses, but can also perform other duties related to traffic safety. Implementation of the RSMAD system will facilitate, inter alia, issuing the fine process and supervision...
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Photogrammetric and computerized report on site model in feasibility study of navigability channel on vistula spit
PublicationIn the report the authors present a course of geodesic and geo-computerized works upon realization of feasibility study of navigability channel on Vistula Spit. A procedure of acquiring verification and modeling of data for requirements of a numeric model of a bottom and site has been presented with construction of original software for 3D visualization of the Vistula Spit area. The activities described in the report can be...
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Local buckling and initial post-buckling behaviour of channel member flange - analytical approach
PublicationThe local buckling and initial post-buckling behaviour of the cold-formed channel member flange is investigated. The governing nonlinear differential equation for axially compressed columns and beams undergoing pure bending is derived using the stationary total potential energy principle. The critical stress and initial post-buckling equilibrium path is determined by means of a perturbation approach. The results obtained allow...
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Exhaust gas temperature measurements in diagnostics of turbocharged marine internal combustion engines. Part I. Standard measurements.
PublicationThe article discusses the problem of diagnostic informativeness of exhaust gas temperature measurements in turbocharged marine internal combustion engines. Theoretical principles of the process of exhaust gas flow in turbocharger inlet channels are analysed in its dynamic and energetic aspects. Diagnostic parameters are defined which enable to formulate general evaluation of technical condition of the engine based on standard...
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Local buckling of thin-walled channel member flange made of aluminum alloy
PublicationThe paper deals with local stability of the thin-walled compressed flange of channel columns and beams made of aluminum alloy. The aim of paper is to find critical stress of local buckling of the flange member taking into account the web-flange interaction in linear and nonlinear elastic range of the member material. The governing differential equation of the problem is derived with aid of the principle of stationary total potential...
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Non-Contact Temperature Measurements Dataset
PublicationThe dataset titled The influence of the distance of the pyrometer from the surface of the radiating object on the accuracy of measurements contains temperature measurements using a selection of four commercially available pyrometers (CHY 314P, TM-F03B, TFA 31.1125 and AB-8855) as a function of the measuring distance. The dataset allows a comparison of the accuracy and measuring precision of the devices, which are very important...
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Sylwester Kaczmarek dr hab. inż.
PeopleSylwester Kaczmarek received his M.Sc in electronics engineering, Ph.D. and D.Sc. in switching and teletraffic science from the Gdansk University of Technology, Gdansk, Poland, in 1972, 1981 and 1994, respectively. His research interests include: IP QoS and GMPLS and SDN networks, switching, QoS routing, teletraffic, multimedia services and quality of services. Currently, his research is focused on developing and applicability...
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Performance analysis of standard and modified EY-NPMA channel access algo-rithms
PublicationPodczas minionego 10-ciolecia notuje się szybki rozwój lokalnych sieci bezprzewodowych (WLANy). Proponowane rozwiązania dotyczą zarówno sieci opartych o przesył komórek (zgodnych z ATM), jak i sieci pakietowych (zgodnych z E-thernetem). Po rozważeniu drugiego z wymienionych typów sieci, wydaje się dzisiaj, iż pakietowe WLANy będą oparte głównie na dwóch standardach, mianowicie: IEEE 802.11 [6]) - wykorzystującym protokół dostępu...
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Next generation radio communication systems (2022)
e-Learning Courses -
Radio reception signals II 2023/2024
e-Learning CoursesKurs będzie narzędziem pomocniczym przy realizacji laboratorium z tego przedmiotu.
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Localization of Mobile Robot Using Radio Waves
PublicationOpisano systemy lokalizacji robotów mobilnych wykorzystujące metody triangulacji i trilateracji, w przestrzeniach dwuwymiarowych. Zaproponowano metodę pomiaru odległości drogą radiową oraz przedstawiono uzyskane wyniki badań.
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Relativistic runaway breakdown in low-frequency radio
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Speech Intelligibility Measurements in Auditorium
PublicationSpeech intelligibility was measured in Auditorium Novum on Technical University of Gdansk (seating capacity 408, volume 3300 m3). Articulation tests were conducted; STI and Early Decay Time EDT coefficients were measured. Negative noise contribution to speech intelligibility was taken into account. Subjective measurements and objective tests reveal high speech intelligibility at most seats in auditorium. Correlation was found between...
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Risk Modelling for Passages in Approach Channel
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Quantum channel capacities: multiparty communication
PublicationAnalizowane są różne aspekty wieloużytkownikowej komunikacji kwantowymi kanałami bez pamięci. Uogólnione zostały pewne znane rezultaty dotyczące komunikacji kwantowej w układzie jeden nadawca -jeden odbiorca. W szczególności pokazana została bezużyteczność komunikacji klasycznej ''w przód'' w procesie transmisji informacji kwantowej oraz równoważność definicji regionów pojemności opartych na różnych miarach wierności transmisji:...
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Transmission properties of a shallow hydroacoustic channel.
PublicationWielokrotne odbicia fali akustycznej od granic ośrodka są przyczyną poważnych ograniczeń możliwości transmisyjnych w płytkich kanałach hydroakustycznych. Zastosowanie modelu BNM kanału, należącego do rezultatów międzynarodowego projektu PROSIM tworzonego w ramach inicjatywy MAST-III, pozwoliło obliczyć funkcje odpowiedzi impulsowych kanału i przeprowadzić symulację transmisji sygnału cyfrowego. Artykuł prezentuje wyniki transmisji...
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Methods of Tire Rolling Resistance Measurements
PublicationTire rolling resistance is one of the factors related to tire/road interaction that has important influence on road vehicles performance. Raising fuel price and increased concern related to the environmental changes result in growing interest in reduction of tire rolling resistance that influences fuel consumption, especially in free-flowing highway traffic with moderate speeds. There are several methods of tire rolling resistance measurements....
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Comparison of commercial thermoluminescent readers regarding high-dose high-temperature measurements
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Journal of Radio & Audio Media
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Secure access control and information protection mechanisms in radio system for monitoring and acquisition of data from traffic enforcement cameras
PublicationThe study presents the architecture of the Radio System for Monitoring and Acquisition of Data from Traffic Enforcement Cameras (in short: RSMAD), particularly concerning access control and protection of confidential data. RSMAD security structure will be discussed in relation to network security issues. Additionally, the paper presents the results of the work associated with the modelling of potential threats to system security.
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Measurements and Simulations of Engineered Ultrasound Loudspeakers
PublicationSimulation and measurement results of the sound emitted from an ultrasound custom-made system with high spatial directivity are presented. The proposed system is using modulated ultrasound waves which demodulate in nonlinear medium resulting in audible sound. The system is aimed at enhancing the users’ personal audio space, therefore the measurements are performed using the Head and Torso Simulator which provides realistic reproduction...
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Local buckling of compressed flange of cold-formed channel members made of aluminum alloy
PublicationThe paper deals with local buckling of a compressed single flange of thin-walled channel cold- formed columns and beams made of aluminum alloy. Material is described by means of the Ramberg-Osgood constitutive equation. Axial compression of the columns and beams undergoing bending is taken into consid- eration. A simple model of the member flange in the form a long beam elastically connected to the web is used to find the critical...
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Buckling and initial post-local buckling behaviour of cold-formed channel member flange
PublicationThe initial post-buckling behaviour of a cold-formed channel member flange after its local buckling is investigated. An axially compressed column or beam subjected to pure bending is considered. The member material is assumed to follow a linear stress-strain relationship. The governing non-linear differential equation of the problem is derived using the minimum total potential energy principle. An approximate solution for the equation...
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Inertial Sensors Applications in Underwater Measurements
PublicationOver the past decades microelectromechanical systems (MEMS) researchers have demonstrated a number of microsensors for almost every possible sensing modality, including attitudes. Current MEMS inertial measurement units (IMU) come in many shapes, sizes, and costs — depending on the application, and performance required. MEMS sensors have proved and demonstrated performance exceeding those of their macroscale counterpart sensors. In...
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Leakage Current Measurements of Surge Arresters
PublicationThe paper presents the methods of assessing the technical condition of varistor surge arresters used in laboratory tests and in operation—performed without disconnecting the arresters from the network. The analysis of the diagnostic methods was supplemented with the results of the measurements of the leakage current of arresters coming directly from their production and used in the power industry. Among the available methods of...
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LABORATORY STAND FOR INVESTIGATIONS OF THE QUICK - CHANGING TEMPERATURE OF GAS FLOWING IN THE PISTON COMPRESSOR OUTLET CHANNEL
PublicationThis paper presents a laboratory stand, created as a part of work on the doctor dissertation, intended for investigation of heat and flow processes taking place in the Espholin H3S piston compressor outlet channel. The test stand elements and their configuration within the stand are described. Discussed are also problems connected with the quick-changing measurement technique, solutions which have been proposed so far in that technology...
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AC loss measurements in superconducting magnet
PublicationThis report contains ordered theoretical informations about AC loss in superconducting magnets and cables. A software program to evaluate data from AC loss measurements with V-I method was made and it is also described. Examples of measurement data and result data are shown here.
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Measurements of flicker noise in supercapacitor cells
PublicationFlicker noise (1/f-like noise) is often used to assess the quality of various materials and devices. This phenomenon has been observed in different electrochemical devices or reactions (e.g., smart windows, pitting corrosion events). In our exploratory studies we consider how to measure and utilize 1/f noise for the quality assessment of supercapacitors. This task requires special attention because of enormous capacitance of the...
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Degradation of reference tyres used for CPX measurements
PublicationMeasurements of tyre/road noise using the Close Proximity Method are based on reference tyres that are described in ISO/TS 11819-3. The standard specifies two tyres, namely "P1" and "H1" that should be used during measurements. To be used for measurements each tyre must fulfill certain conditions that are listed in the standard. The conditions are related to the tread pattern depth and rubber hardness. During experiments performed...
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Do Leonardo da Vinci’s drawings, room acoustics and radio astronomy have anything in common?
PublicationAfter introducing Leonardo da Vinci’s (LdV) predecessors in the field of light propagation research, his drawings on the topic of reflecting light by a spherical mirror are analysed. The discovery of LdV is presented, according to which, at an infinitely distant source of rays, a small fragment of the canopy is enough to generate a focus, while the rest of the mirror forms a caustic for which LdV did not indicate an application....
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Validation of a virtual test environment for C2X communication under radio jamming conditions
PublicationIn this paper, we propose a novel car-2-x communication security testing methodology in the physical layer of wireless systems. The approach is dedicated to automated testing of autonomous vehicles and it is essential for such complex systems operation, especially with regard to safety and security issues. It is based on scenario-driven testing in virtual and real test environments created from collected or simulated data. The...
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A method for testing the wide-sense stationary uncorrelated scattering assumption fulfillment for an underwater acoustic channel
PublicationWide-sense stationary and uncorrelated scattering (WSSUS) assumptions are often applied for the statistical description of wireless communication channels. However, in the case of underwater acoustic channels the WSSUS model is of limited value. The degree of similarity of in-phase and quadrature components of the channel impulse response, measured with the use of bandpass modulated signals, can be used as an indicator of WSSUS...