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Wyniki wyszukiwania dla: SMALL SIGNAL, GENERAL AVERAGE MODELING, DUAL-ACTIVE-BRIDGE CONVERTER, TRIPLE-PHASE-SHIFT CONTROL,
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Rola parków naukowo-technologicznych w modelu triple helix na przykładzie parków Polski Wschodniej
PublikacjaCelem artykułu jest omówienie roli parków naukowo-technologicznych w modelu triple helix, zarówno w aspekcie teoretycznym, jak i w oparciu o przeprowadzone badania empiryczne. Autorki zaprezentowały wyniki badańdotyczących powiązań wybranych parkówz pozostałymi grupami aktorów wyróżnionymi w modelu triple helix, ze szczególnym uwzględnieniem instytucji B+R, władz publicznych oraz innych instytucji pośredniczących. Badania przeprowadzono...
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Design and Implementation of a Dual-band Filtering Wil-kinson Power Divider Using Coupled T-shaped Dual-band Resonators
PublikacjaThe paper introduces a novel structure of a dual-band filtering Wilkinson power divider (WPD). Its essential component is a dual-band bandpass filter (BPF), implemented using coupling lines and two T-shaped resonators. The BPF is incorporated into the divider structure to suppress the unwanted harmonics within the circuit. The latter is achieved owing to a wide stopband of the filter. The deigned dual-band WPD can suppress third...
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Transient modeling in common DC link of power converters
PublikacjaПредмет исследования. Представлена математическая модель силовых преобразователей электропривода, питающихся от общего звена постоянного тока, на примере тяговых электроприводов карьерного самосвала БЕЛАЗ-90 мощностью 280 кВт. Модель выполнена в пакете MATLAB/Simulink. Новизна предложенной модели заключается в применении новой топологии силовой схемы для исследования работы двух инверторов, под- ключенных к одному звену постоянного...
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Intelligent Autonomous Robot Supporting Small Pets in Domestic Environment
PublikacjaIn this contribution, we present preliminary results of the student project aimed at the development of an intelligent autonomous robot supporting small pets in a domestic environment. The main task of this robot is to protect a freely moving small pets against accidental stepping on them by home residents. For this purpose, we have developed the mobile robot which follows a pet and makes an alarm signal when a human is approaching....
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Some aspects of vibration control. Part I: Active and passive correction.
PublikacjaPrzedstawiono ogólne podejście do modyfikacji układu mechanicznego w ruchu harmonicznym przy użyciu aktywnych i pasywnych metod. Zaproponowano metodę wyznaczania elementów macierzy układu lub struktury i nastaw regulatora, zapewniającą najefektywniejsze oddziaływanie na dynamikę ruchu.
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Some aspects of vibration control. Part II: An optimal active controller.
PublikacjaPrzedstawiono teoretyczną metodę optymalnego, z punktu widzenia przyjętego wskaźnika jakości, oddziaływania na drgania liniowego układu mechanicznego. Metoda ta może być stosowana do zmniejszenia drgań układów wirujących, np. drgań okrętowych układów napędowych z silnikami tłokowymi czy drgań wirników turbinowych wywołanych biciem filmu olejowego lub siłami aerodynamicznymi.
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Problems of Active Dynamic Thermography Measurement Standardization in Medicine
PublikacjaReliability of thermographic diagnostics in medicine is an important practical problem. In the field of static thermography, a great deal of effort has been made to define the conditions for thermographic measurements, which is now the golden standard for such research. In recent years, there are more and more reports on dynamic tests with external stimulation, such as Active Dynamic Thermography, Thermographic Signal Reconstruction...
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Small signal admittance spectroscopy applied for extraction of charge carrier mobility in thin organic layers
PublikacjaPraca przedstawia nowy sposób wyznaczania ruchliwości nośników ładunku w cienkich warstwach organicznych w oparciu o pomiary widm małosygnałowej admitancji.
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A non-quasi-static small-signal model of the four-terminal MOSFET for radio and microwave frequencies.
PublikacjaW pracy zaprezentowano nowy małosygnałowy model tranzystora MOS, w którymuwzględnia się efekt nasycenia prędkości nośników. Model jest spójny fizycznie i może być stosowany w analizie dowolnej konfiguracji włączenia tranzystora.
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Numerical analysis and in situ tests of the Grot Rowecki Bridge in Warsaw
PublikacjaThe paper presents the FEM analysis of the reconstructed the Grot-Rowecki Bridge over Vistula river in Warsaw. The bridge has seven spans and consists of two independent structures with the longest spans of 120 m. After reconstruction the bridge is over 10 m wider. The numerical, nonlinear analysis has been con-ducted on a global and local FEM models. These models are defined so as they strictly comply with global structural bridge...
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A Simplified SPWM Scheme for a Compact 3-Level Dual-Output Inverter
PublikacjaSinusoidal Pulse-width modulation, SPWM, is inverter-leg-based, logical-operation-based, and lesscomputational-intensive. In this brief, these simplifying features of SPWM are extended to the control of the 10-switch, 3-level inverter. The control strategy is based on the single triangular carrier SPWM perspective. Procedures and details of the sharing of four-common power switches by the 3 inverter legs are given. Classically,...
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Stress analysis of the bridge hangers in terms of the fatigue verification
PublikacjaThe paper presents the results of numerical stress analysis of the bridge rod hangers. Two types of hangers were taken into account, i.e. the bolted hanger and the welded hanger. A detailed FEM shell models of the connection area between the hanger and the bridge span have been developed. Local stress concentration effects have been investigated in terms of fatigue verification.
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Baltic Journal of Road and Bridge Engineering
Czasopisma -
Histogram of Oriented Gradients with Cell Average Brightness for Human Detection
PublikacjaA modification of the descriptor in a human detector using Histogram of Oriented Gradients (HOG) and Support Vector Machine (SVM) is presented. The proposed modification requires inserting the values of average cell brightness resulting in the increase of the descriptor length from 3780 to 3908 values, but it is easy to compute and instantly gives ≈ 25% improvement of the miss rate at 10‒4 False Positives Per Window (FPPW). The...
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The Bridge of Data Project Objectives
PublikacjaOpen Research Data (ORD) is one of the emerging trends for researchers across the globe. However, it has to be stressed that the level of implementation and awareness of ORD varies between countries. Many initiatives have been created in Polish scientific institutions to support the process of opening publications. These are mainly Open Access (OA) repositories, implementing the so-called green road of OA. However, only a few universities...
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Application of wireless communication to small WECS with induction generator
PublikacjaWind energy conversion systems (WECS) seem to be self-evident elements of the future smart grids. Among many generator types the squirrel cage induction generator (SCIG) characterizes robustness and low cost. A full-scale power converter can perform smooth grid connection over wide speed range of multiple-stage geared SCIG. Increasing number of sensors can improve the WECS control and diagnostics but increasing number of thin wires...
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Suppression of Supply Current Harmonics of 18-Pulse Diode Rectifier by Series Active Power Filter with LC Coupling
PublikacjaThe reported research aims at improving the quality of three-phase rectifier supply currents. An effective method consists of adding properly formed booster voltages to the fundamental supply voltages using a series active filter. In the proposed solution, the booster voltages are generated by three single-phase systems consisting of inverters, LC filters, and single-phase transformers. The application of LC couplings ensures low...
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Starter for Voltage Boost Converter to Harvest Thermoelectric Energy for Body-Worn Sensors
PublikacjaThis paper examines the suitability of selected configurations of ultra-low voltage (ULV) oscilla-tors as starters for a voltage boost converter to harvest energy from a thermoelectric generator (TEG). Important properties of particularly promising configurations, suitable for on-chip imple-mentation are compared. On this basis, an improved oscillator with a low startup voltage and a high output voltage swing is proposed. The applicability...
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Design advantages and analysis of a novel five-phase doubly-fed induction generator
PublikacjaPurpose – The purpose of this paper is to provide an analysis of the performance of a new five-phase doubly fed induction generator (DFIG). Design/methodology/approach – This paper presents the results of a research work related to fivephase DFIG framing, including the development of an analytical model, FEM analysis as well as the results of laboratory tests of the prototype. The proposed behavioral level analytical model is based...
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Closer Look at the Uncertainty Estimation in Semantic Segmentation under Distributional Shift
PublikacjaWhile recent computer vision algorithms achieve impressive performance on many benchmarks, they lack robustness - presented with an image from a different distribution, (e.g. weather or lighting conditions not considered during training), they may produce an erroneous prediction. Therefore, it is desired that such a model will be able to reliably predict its confidence measure. In this work, uncertainty estimation for the task...
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The bridge over Regalia River in Szczecin - design and construction.
PublikacjaNowoclowa Route is the largest projekt in Szczecin, that consists of 11 km of roads 3,3 km bridges and viaducts, including three parallel bridges across Regalica River (the east arm of Odra River), 535 m long, with the spans: 59+90+90+116+116+64m. The bridge structure consist of two steel plate girders composite with reinforced concrete deck slab. The design and the construction of the bridge are described in the paper.
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Systems of General Grants for Local Governments in Selected EU Countries Against the Background of the General Theory of Fiscal Policy
PublikacjaFiscal policy, including its expenditure aspect, is often discussed and analysed from a variety of angles in the literature on public finances, undoubtedly due to the major importance of this topic. However, not all areas of the expenditure part of fiscal policy have been subjected to in-depth analysis. One of the less discussed tools of fiscal policy consists of general purpose transfers, which are a certain type of expenditure...
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Research on Linear Actuators for Active Foil Bearings
PublikacjaActive foil bearings are a kind of gas foil bearing. They contain actuators which allow for modification of the bearing sleeve size and the shape of the lubrication gap. Rotor vibrations can be actively controlled by these changes. It is possible, among other things, to reduce the starting torque, control the vibration amplitude at different speeds and improve operational safety. Prototypes of active foil bearings are being developed...
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Inverse surrogate models for fast geometry scaling of miniaturized dual-band couplers
PublikacjaRe-design of microwave structures for various sets of performance specifications is a challenging task, particularly for compact components where considerable electromagnetic (EM) cross-couplings make the relationships between geometry parameters and the structure responses complex. Here, we address geometry scaling of miniaturized dual-band couplers by means of inverse surrogate modeling. Our approach allows for fast estimation...
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Multi-transformer primary-side regulated flyback converter for supplying isolated IGBT and MOSFET drivers
PublikacjaThis paper presents primary-side voltage regulated multi-transformer quasi-resonant flyback converter (MTFC) for supplying isolated power switch drivers. The proposed topology offers distinct advantages over frequently used flyback converter possessing one high frequency transformer with isolated multiple outputs. Particularly, when a large number of separate dc supply units is required, then MTFC enables improved regular distribution...
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Application of guided wave propagation in diagnostics of steel bridge components
PublikacjaEarly detection of potential defects and identification of their location are necessary to ensure safe, reliable and long-term use of engineering structures. Non-destructive diagnostic tests based on guided wave propagation are becoming more popular because of the possibility to inspect large areas during a single measurement with a small number of sensors. The aim of this study is the application of guided wave propagation in...
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Accurate modeling of quasi-resonant inverter fed IM drive
PublikacjaIn this paper wide-band modeling methodology of a parallel quasi-resonant dc link inverter (PQRDCLI) fed induction machine (IM) is presented. The modeling objective is early-design stage prediction of conductive electromagnetic interference (EMI) emissions of the considered converter fed IM drive system. Operation principles of the selected topology of PQRDCLI feeding IM drive are given. Modeling of the converter drive system is...
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A New Geodetic Method of Examination of Geometrical Conditions of a Crane Bridge
PublikacjaSafety is one of the key aspects related to crane-based material transport. In order to ensure safe crane operation and material transport, it is necessary to meet certain geometrical conditions. The authors addressed the geometrical conditions of a crane bridge, a substantial crane component. The paper presents the method to compute displacement components of points on the top of a bridge crane relative to their design position....
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Prediction of ringing frequencies in DC-DC boost converter
PublikacjaIn the paper ringing phenomena in a DC-DC boost converter is presented. The ringing frequency is calculated using an analytical formula. The necessary wide band models of MOSFET transistor, passive and parasitics are described. The calculation results are verified in simulation and laboratory tests.
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Magdalena Gajewska prof. dr hab. inż.
OsobyMagdalena Gajewska (ur. 1.06.1968 r. w Gdańsku) ukończyła studia w 1993 roku na Wydziale Hydrotechniki Politechniki Gdańskiej. Jest adiunktem w Katedrze Technologii Wody i Ścieków na Wydziale Inżynierii Lądowej i Środowiska Politechniki Gdańskiej. Doktorat (2001) i habilitacja (2013) w dyscyplinie inżynierii środowiska. W kadencji 2016–2020 pełni funkcję prodziekana ds. nauki. Specjalizuję się w technologiach związanych z ekoinżynierią:...
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High Performance Control of AC Drives with Matlab/ Simulink
PublikacjaExplore this indispensable update to a popular graduate text on electric drive techniques and the latest converters used in industry. The Second Edition of High Performance Control of AC Drives with Matlab®/Simulink delivers an updated and thorough overview of topics central to the understanding of AC motor drive systems. The book includes new material on medium voltage drives, covering state-of-the-art technologies and challenges...
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Numerical Modeling of Hydrosystems 2022/2023 (summer)
Kursy OnlineKurs do przedmiotu NUMERICAL MODELING OF HYDROSYSTEMS Specjalność: Environmental Engineering (WILiŚ), II stopnia, stacjonarne dr hab. inż. Michał Szydłowski, prof. PG
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Numerical Modeling of Hydrosystems 2022/2023 (winter)
Kursy OnlineKurs do przedmiotu NUMERICAL MODELING OF HYDROSYSTEMS Specjalność: Environmental Engineering (WILiŚ), II stopnia, stacjonarne dr hab. inż. Michał Szydłowski, prof. PG
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Anna Witkowska dr hab.
OsobyAnnaWitkowska holds an M.Sc. in mathematics and computer science from the University of Gdańsk, Poland in 2001. She received her Ph.D. degree from the Technical University of Warsaw in 2011, and the D.Sc. (habilitation) degree in automation, electronic and electrical engineering from the Technical University of Gdańsk, in 2020. Currently she is a professor of the Gdańsk University of Technology, Faculty of Electrical and Control...
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Study of passive deck-flaps flutter control system on full bridge model. II: Results
PublikacjaZaprezentowano badania parametryczne systemu sterowania flatterem przy pomocy dołączonych stateczników na modelu wyprowadzonego w formalizmie metody elementów skończnych. Wyniki wskazują na efektywność systemu stosującego symetryczne sprzężenie ruchu stateczników z ruchem skrętnym mostu.
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Study of passive deck-flaps flutter control system on full bridge model. I: Theory
PublikacjaSformułowano modele matematyczne drgań mostu z zamontowanym pasywnym systemem sterowania flatterem w formalizmie metody elementów skończonych. System wykorzystuje stateczniki dołączone bezpośrednio do przęsła mostu. Siły aerodynamiczne działające bezpośrednio na most i stateczniki sformułowane są w przestrzeni czasu.
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Hybrid stepless distribution transformer with four-quadrant AC/DC/AC converter at low voltage side - simulation tests
PublikacjaThe article presents the work of the stepless hybrid distribution transformer (HT), as an alternative to the so far applied Automatic Voltage Regulator (AVR) solutions, used to control the voltage in the power system in terms of the fundamental harmonic. The HT is a combination of a conventional distribution transformer and an AC/DC/AC converter connected in series with the transformers secondary winding. In the work the basic...
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Modeling of production planning and control process consistent with theory of constraint
PublikacjaArtykuł dotyczy problematyki zastosowania metody werbel-bufor-lina do planowania produkcji w systemach produkcyjnych z wielokrotnymi buforami. W artykule przedstawiono algorytm - jego funkcje, dane wejściowe i wyjściowe - który może mieć zastosowanie do modelowania procesu planowania i sterowania produkcją. Algorytm umożliwia określenie wielkości czasowych buforów w systemie oraz terminów rozpoczęcia i zakończenia realizacji zadań....
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EMI attenuation in a DC-DC buck converter using GaN HEMT
PublikacjaA dc-dc buck converter using gallium nitride (GaN) high electron mobility transistors (HEMT) is experimentally investigated at the discontinuous current mode (DCM) and at the triangular current mode (TCM) operation. The paper objective is to specify the power conversion efficiency and attenuation of common mode (CM) and differential mode (DM) noise voltage, measured at the line impedance stabilization network (LISN) for compared...
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Using phase of short-term Fourier transform for evaluation of spectrogram performance
PublikacjaThe concept of spectrogram performance evaluation which exploits information on phase of short-term Fourier transform (STFT) is presented. A spectrograph which is time-frequency analyzing tool, is compared to a filter bank that demultiplexes a signal. Local group delay (LGD) and channelized instantaneous frequency (CIF) is obtained for each filtered component signal. In presented solution the performance is evaluated using so-called...
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Computer modeling and design of materials 2022/2023
Kursy OnlineComputer modeling and design of materials, kierunek: Nanotechnologia, specjalność: Mathematics for new materials design, II stopień, semestr 3
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Seismic Pounding Between Bridge Segments: A State-of-the-Art Review
PublikacjaEarthquake-induced structural pounding in bridge structures has been observed in several previous seismic events. Collisions occur at the expansion joints provided between adjacent decks or between the deck and abutment. Pounding between the structural elements may lead to severe damages and even to the unseating of the bridge in certain cases. Several investigations have been performed to study pounding in bridges under uniform...
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Research on methods for detecting respiratory rate from photoplethysmographic signal
Publikacja -
A General Synthesis of Diaryl Cyclic Diamidines
PublikacjaA convenient and general method has been developed for directly converting bis-nitriles, e.g., I, to cyclic diamidines, e.g., II, using reagents derived from diaminoalkanes, e.g., H2NCH2CH2NH2, satd. with hydrogen sulfide. A 1:1 mixt. of a diaminoalkane and Et alc. (or without) was effective in most cases (72-88%). The synthetic utility of this methodol. in the prepn. of tetrakis(cyclic amidino)pyrenes III (R = H, Me) from 1,3,6,8-tetracyanopyrene...
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Cascaded Buck Hybrid Interlink Converter for Multiple-Input / Multiple-Output Operation
PublikacjaThe provision of isolated- and non-isolated DC output voltages by Power electronics power-conditioning devices in the recent ‘green-energy-revolution’ era is on course. In this paper, a structure for multi-input multi-output(MIMO) DC–DC buck converter is proposed to generate output voltages of varying levels with fewer component-count. The DC output voltage of each of the constituting buck converters can be used independently or...
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Measurements of Dispersed Phase Velocity in Two-Phase Flows in Pipelines Using Gamma-Absorption Technique and Phase of the Cross-Spectral Density Function
PublikacjaThis paper concerns the application of the gamma radiation absorption method in the measurements of dispersed phase velocity in two-phase flows: liquid–gas flow in a horizontal pipe- line and liquid–solid particles in a vertical pipe. Radiometric sets containing two linear 241Am gamma radiation sources and two NaI(Tl) scintillation detectors were used in the research. Due to the stochastic nature of the signals obtained from the...
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General Genetics QUIZZ
Kursy OnlineCelem wykładu będzie zapoznanie Studentów z najważniejszymi odkryciami, prawami i terminami genetyki. Wykład będzie obejmował kluczowe zagadnienia genetyki: zasady dziedziczenia cech i chorób, mechanizmy regulacji ekspresji genów i mechanizmy zmienności genetycznej. Wykład będzie kładł duży nacisk na wyjaśnienie, szczególnie istotnego dla biotechnologów, molekularnego podłoża dziedziczności, zmienności genetycznej i regulacji...
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General Genetics webinarium_3.04.2020
Kursy OnlineWykład przybliżający studentom problemy Genetyki ogólnej, prowadzony w języku angielskim.
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On small signal capacitance spectra of organic diode formed by ITO-palladium phthalocyanine-Al sandwich system
PublikacjaPraca poświęcona jest widmom małosygnalowej pojemności w zakresie 25 Hz-1 MHz i charakterystyce prądowo-napięciowej planarnego układu utworzonego przez ITO/ftalocyanina palladu/Al.
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Dynamic analysis of the railway bridge span under moving loads
PublikacjaThe first part of this paper provides a review of the state of knowledge of the dynamic behaviour of railway bridges under moving loads. Particular attention is paid to developments in modelling railway bridge loading and dynamic vehicle-span (structure) interaction. The most important aspects determining the advancements in this area of knowledge are identified. The contemporary techniques for defining bridge span finite element...