Search results for: TRAJECTORY COMPRESSION
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Modeling and control of a redundantly actuated variable mass 3RRR planar manipulator controlled by a model-based feedforward and a model-based-proportional-derivative feedforward–feedback controller
PublicationIn the paper, dynamics of a complex mechatronics system is considered. A redundantly actuated planar manipulator is the base of the mechanical part of it. It is a 3RRR 1 platform based parallel manipulator. To control its trajectory, a model-based feedforward controller is employed. Three aspects are fundamental in the presented investigations. The first focus is on development of an accurate numerical model used to solve the inverse...
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Analysis and assessment of the acoustic emission suitability for determination of the energy states of a tribological system in the form of a four-ball tester friction node
PublicationThe present operating safety and cost reduction requirements of the compression ignition engines make it necessary to search for new methods of detecting their defects, e.g. by the analysis of acoustic emission signals coming from the slide bearings. The paper presents non-destructive measurements of acoustic emission (AE) in order to obtain information on the processes taking place in a tribological system under the continuously...
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Paweł Szymon Dąbrowski dr inż.
PeopleDr. Eng. Paweł Szymon Dąbrowski studied geodesy and cartography at the University of Warmia and Mazury in Olsztyn from 2004-2009, where he obtained the title of Master of Science in Engineering. In the years 2009-2016, he worked as a land surveyor in Iława and Gdańsk. He gained professional experience during the construction of the Pomeranian Metropolitan Railway, which helped him obtain a national surveying license in 2015. In...
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Effect of temperature and ionic strength on volumetric and acoustic properties of solutions of urea alkil derivatives in aqueous NaCl
PublicationThe present work was undertaken to study volumetric and acoustic properties for diluted solutions of tetramethylurea in pure water and for urea, n-propylurea, n-butylurea and tetramethylurea in 0.5 or 1 moldm3 aqueous solutions of sodium chloride. This paper presents measured values of densities and sound velocities at T = (288.15, 298.15 and 308.15) K. From these data the apparent molar volumes, , adiabatic compressibilities,...
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Running characteristics of aerodynamic bearing with self-lifting capability at low rotational speed
PublicationAn aerodynamic journal bearing that is capable of self-generating squeeze-film pressure is presented and its dynamic characteristics investigated numerically and experimentally. A numerical method based on a time marching static model was applied to assess the orbit trajectory path of the rotor upon a perturbation. Experimental results were obtained to validate the effect of the self- generated squeeze-film pressure on the stability...
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LCF behavior of 2024AA under uni- and biaxial loading taking into account creep pre-deformation
PublicationThis study presents the results of experimental low-cycle fatigue (LCF) tests of aluminum 2024 alloy T3511 temper in uni- and biaxial loading states. Tests were carried out on both the as-received material (hardened extruded rods) and material with different pre-deformation histories. These deformations were carried out in the creep process at 200 °C and 300 °C for two different levels of at each temperature. The pre-deformed material’s...
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Influence of rhamnolipids and ionic cross-linking conditions on the mechanical properties of alginate hydrogels as a model bacterial biofilm
PublicationThe literature indicates the existence of a relationship between rhamnolipids and bacterial biofilm, as well as the ability of selected bacteria to produce rhamnolipids and alginate. However, the influence of biosurfactant molecules on the mechanical properties of biofilms are still not fully understood. The aim of this research is to determine the effect of rhamnolipids concentration, CaCl2 concentration, and ionic cross-linking...
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The evaluation of the vibration measurement usability of electronic indicator lemag "premet C"
PublicationThe measuring possibilities of modern compression and combustion pressure analyzers are extended with additional functions. One of them is parallel to the pressure measurement, the measurement of vibrations in the region of the cylinder head. The paper presents a general assessment of the vibration measurement function of the electronic indicator LEMAG "PREMET C". This feature is very rarely offered by manufacturers of these devices....
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Joanna Janczewska prof. dr hab.
PeopleJoanna Janczewska obtained her PhD degree at the University of Gdansk in 2002. From October 1999 to September 2004 she was an assistant at the University of Gdansk. Since October 2004 she has been an assistant professor at the Gdansk University of Technology. Moreover, from October 2008 to September 2010 she had a visiting position in the Institute of Mathematics of the Polish Academy of Sciences. Her mathematical interests...
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A Proposed Soft Computing Model for Ultimate Strength Estimation of FRP-Confined Concrete Cylinders
PublicationIn this paper, the feed-forward backpropagation neural network (FFBPNN) is used to propose a new formulation for predicting the compressive strength of fiber-reinforced polymer (FRP)-confined concrete cylinders. A set of experimental data has been considered in the analysis. The data include information about the dimensions of the concrete cylinders (diameter, length) and the total thickness of FRP layers, unconfined ultimate concrete...
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Automatic Analysis of Trajectories of Moving Objects
PublicationOngoing monitoring is essential to providing security and safety of maritime and air operations. This paper presents the research in the area of automatic analysis of movement of unrestricted vehicles like ships and air-planes. The analysis is aimed at extraction of trajectory information, and the results can be used to identify anomalous behaviour in archived and real-time data. In this paper we focus on data acquired using the...
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Mixed, quantum-classical description of electron density transfer in the collision process
PublicationIn this work, we investigate an ion-atom model describing the time-dependent evolution of electron density during the collision. For a S3+- H system, numerical simulations are based on classical trajectory calculations, and the electron density behaviour is described with the time-dependent Schrödinger equation. We apply the finite difference method to obtain quantitative insights into the charge transfer dynamics, providing detailed...
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Regularized Local Basis Function Approach to Identification of Nonstationary Processes
PublicationThe problem of identification of nonstationary stochastic processes (systems or signals) is considered and a new class of identification algorithms, combining the basis functions approach with local estimation technique, is described. Unlike the classical basis function estimation schemes, the proposed regularized local basis function estimators are not used to obtain interval approximations of the parameter trajectory, but provide...
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Akcelerator predykcji wewnątrzramkowej H.264 do kompresji obrazu w sensorach wizyjnych
PublicationW artykule przedstawiono konfigurowalny cyfrowy akcelerator predykcji wewnątrzramkowej przeznaczony dla enkodera wideo standardu H.264. Akcelerator realizuje predykcję typu „intra” dla makrobloków luminancji o wymiarach 4x4 i 16x16. Akcelerator wstępnie zaimplementowano w układzie FPGA, gdzie został on pomyślnie zweryfikowany, a następnie zaimplementowano go w układzie ASIC w technologii UMC 90 nm. Szczegółowe wyniki testów akceleratora...
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Akcelerator predykcji wewnątrzramkowej H.264 do kompresji obrazu w sensorach wizyjnych
PublicationW komunikacie przedstawiono konfigurowalny cyfrowy akcelerator predykcji wewnątrzramkowej przeznaczony dla enkodera wideo standardu H.264. Akcelerator realizuje predykcję typu „intra” dla makrobloków luminancji o wymiarach 4x4 i 16x16. Akcelerator wstępnie zaimplementowano w układzie FPGA, gdzie został on pomyślnie zweryfikowany, a następnie zaimplementowano go w układzie ASIC w technologii UMC 90 nm. Szczegółowe wyniki testów...
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Towards More Realistic Probabilistic Models for Data Structures: The External Path Length in Tries under the Markov Model
PublicationTries are among the most versatile and widely used data structures on words. They are pertinent to the (internal) structure of (stored) words and several splitting procedures used in diverse contexts ranging from document taxonomy to IP addresses lookup, from data compression (i.e., Lempel- Ziv'77 scheme) to dynamic hashing, from partial-match queries to speech recognition, from leader election algorithms to distributed hashing...
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Feasibility of combined diesel engine - steam turbine in power station operating in the maritime
PublicationCompression-ignition engines used in ship technology as main propulsion engines are large units reaching even to 50-60 MW. Currently, the efficiency of such engines amounts to 45-50%. With such a large power unit, exhaust gases leaving the engine contain very large quantities of heat available for further treatment. Exhaust gases from the piston engine contain about 25% of the heat supplied to the engine in the fuel. Using the...
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Experimental observations on the creep behaviour of frozen soil
PublicationConstitutive models in the literature for creep of frozen soil are based on the direct use of time counted from the onset of creep. An explicit time dependence in a constitutive equation violates the principles of rational mechanics. No change in stress or temperature is allowed for during creep, using the time-based formulations. Moreover, the existing descriptions need much verification and improvement on the experimental side...
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Compact and Integrated High-Power Pulse Generation and Forming System
PublicationThis paper presents comprehensive analytical, numerical and experimental research of the compact and integrated high-power pulse generation and forming system based on the flux compression generator and the electro-explosive forming fuse. The paper includes the analysis of the presented solution, starting from the individual components studies, i.e., the separate flux compression generator tests in field conditions and the forming...
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Structural Assessment of Reinforced Concrete Beams Incorporating Waste Plastic Straws
PublicationThe behavior of reinforced concrete beams containing fibers made of waste plastic straws (WPSs) under the three point bending test is examined. The effect of WPS fiber addition on the compressive and split tensile strength is reported. Four concrete mixes were prepared. The control mix PS-0 had a proportion of 1 cement: 1 sand: 2 coarse aggregate and a water cement ratio of 0.4. In the other three mixes PS-0.5, PS-1.5 and PS-3,...
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Numerical simulation of screw displacement pile interaction with non-cohesive soil
PublicationA trial numerical simulation of screw displacement pile interaction with non-cohesive subsoil during the transfer of compression load. The simulation was carried out in an axisymmetric system. The technological phases of pile installation in the ground were numerically modelled using equivalent processes which provided similar effects to real technical actions. The results of the numerical calculations were verified by comparing...
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An algorithm for enhancing macromodeling in finite element analysis of waveguide components
PublicationAn algorithm for enhancing the finite element method with local model order reduction is presented. The proposed technique can be used in fast frequency domain simulation of waveguide components and resonators. The local reduction process applied to cylindrical subregions is preceded by compression of the number of variables on its boundary. As a result,the finite element large system is converted into a very compact set of linear...
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Numerical Modelling of Shear Localization in Granular Bodies using MPM and Non-local Hypoplasticity
PublicationThe paper deals with modelling of shear localization in granular bodies by means of an enhanced hypoplastic constitutive model and material point method (MPM). The calculations were carried out for plane strain compression of non-cohesive sand. In order to properly capture the width and inclination of shear zones, the constitutive model was enriched by a characteristic length of micro-structure by means of a non-local theory....
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Fuzzy rule-based dynamic gesture recognition employing camera & multimedia projector
PublicationIn the paper the system based on camera and multimedia projector enabling a user to control computer applications by dynamic hand gestures is presented. The main objective is to present the gesture recognition methodology which bases on representing hand movement trajectory by motion vectors analyzed using fuzzy rule-based inference. The approach was engineered in the system developed with J2SE and C++ / OpenCV technology. OpenCV...
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Some aspects of the constitutive modelling of natural fine grained soils
PublicationThe monograph deals with selected problems of the constitutive modelling of natural fine grained soils commonly known as clays. The main idea is not to propose a unified model which is capable of describing all known features of mechanical behaviour of fine grained soils. Instead, separate models are proposed describing the mechanical behaviour of heavily overconsolidated, lightly overconsolidated and normally consolidated clays....
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Combined cold supply system for ship application based on low GWP refrigerants - Thermo-economic and ecological analyses
PublicationThe withdrawal of popular high-GWP refrigerants will significantly affect maritime industry. Refrigeration and air conditioning systems currently used on ships are not ready to fulfil future limitations. Therefore, there is a need for system, which will operate with low-GWP refrigerants and at the same time will be efficient and reliable in difficult environmental conditions. This paper explains the concept of a cold supply system,...
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Analyses of Shear Angle in Orthogonal Cutting of Pine Wood
PublicationThe determination of energy effects for wood machining processes, such as cutting power and cutting forces, is very useful in designing of manufacture process of wooden products. A more accurate prediction of cutting forces requires a correct determination of the shear angle value, which can be determined using various models. In this article, shear angle values for an orthogonal linear cutting process of pine wood are determined. The...
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LEGAL ASPECTS OF ELECTRIC ENERGY GENERATION IN A FLOATING POWER PLANT
PublicationThis paper discusses the characteristics of pollution and legal regulations governing investment projects affecting the environment. It describes a combined system of a compression ignition engine and a steam turbine, whose aim, when placed on a floating platform, is to produce electric energy in a so-called distributed generation system. Such a system involves a reciprocating internal combustion engine and a connected steam turbine...
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Computations of critical load value of composite shell with random geometric imperfections
PublicationThe work presents the numerical analysis of composite shell with geometric imperfections subjected to compression along its generatrix. The imperfections are described as single indentations and random fields with random parameters of shape and correlation. The fields are generated with the use of the authors made program. Using the authors’ FEM software as well as commercial package Femap with NX Nastran, the critical load values...
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Model matematyczny strat objętościowych ściskania oleju hydraulicznego w pompie wyporowej o zmiennej wydajności
PublicationCelem pracy było stworzenie możliwości oceny strat objętościowych wynikających ze ściskania oleju hydraulicznego w komorach roboczych wysokociśnieniowej pompy wyporowej o zmiennej wydajności na obrót wału. Straty objętościowe ściskania oleju muszą być określone jako funkcje tych samych parametrów, w zależności od których ocenione są straty objętościowe przecieków oleju w komorach, wynikające z jakości rozwiązania konstrukcyjnego...
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Weak forms of shadowing in topological dynamics
PublicationWe consider continuous maps of compact metric spaces. It is proved that every pseudotrajectory with sufficiently small errors contains a subsequence of positive density that is point-wise close to a subsequence of an exact trajectory with the same indices. Also, we study homeomor- phisms such that any pseudotrajectory can be shadowed by a finite number of exact orbits. In terms of numerical methods this property (we call it multishadowing)...
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Distribution of the displacement sequence of an orientation preserving circle homeomorphism
PublicationIn some applications not only the knowledge of the behaviour of trajectories of a map is important, but also their displacements. We describe in detail the distribution of elements of the displacement sequence along a trajectory of an orientation preserving circle homeomorphism ϕ with irrational rotation number ϱ(ϕ). The values of displacement are dense in a set which depends on the map γ (semi-)conjugating ϕ with the rotation...
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Thermodynamic Cycles of Air Microturbine Power Plants Working on Biomass Fuels
PublicationThe gas turbine engine is modified to work as an air turbine set which consists, in the simplest arrangement, of a compressor, a heat exchanger and a turbine. Air is a working medium for both: the compressor and the turbine. This kind of air turbine set can be applied in power plants working on biomass fuels. In this solution we can burn fuels of varying parameters in the external combustion chamber without any harmful effects...
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The forming and emission of high power electromagnetic pulses
PublicationAn impulse energy source, a power conditioning system and an electromagnetic field emitter are essential to generate an electromagnetic field pulse (EMFP) with a specific frequency bandwidth. Selected simulation results for a power conditioning system consisting of a fuse opening switch and a paraboloidal electromagnetic emitter have been presented in this article. The synthetic system examined in the simulation is powered by an...
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Load carrying capacity of the eccentric joint in the truss made of open cross-sections
PublicationThe influence of eccentricity at intersections of truss members on the load carrying capacity of the truss joint is presented in the paper. The research truss elements were designed as cold-formed open cross section. Analytical calculations, numerical analysis and experimental research were conducted to reveal how the eccentricity affects the effort of material in the joint area. The results of analysis and investigations are compared...
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Experimental investigation of joint with positive eccentricity in CFS truss
PublicationDue to technological restrictions, in the case of trusses made of CFS open cross-sections, positive eccentricities in the truss joints have become very frequent. Therefore studies concerning the load-bearing capacity of truss joints with positive eccentricity were undertaken. It was assumed that the resistance of cold-formed steel (CFS) open cross-section truss joints located on compression chords and with positive eccentricity...
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Wybrane zagadnienia przepływowe turbiny gazowej pracującej w tłoczni gazu ziemnego.
PublicationW niniejszym artykule przedstawiono cieplno-przepływowe obliczenia turbiny gazowej, stanowiącej napęd sprężarki w tłoczni gazu ziemnego. Wartości parametrów wejściowych niezbędnych do przeprowadzenia obliczeń przyjęto na podstawie danych technicznych tłoczni zasilających polski odcinek gazociągu tranzytowego Jamał-Europa, w których pracują turbiny gazowe SGT-600 firmy Siemens, o mocy 25,3 MW.
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A Time Delay Controller Included Terminal Sliding Mode and Fuzzy Gain Tuning for Underwater Vehicle-Manipulator Systems
PublicationAn improved Time Delay Control (TDC) method for an Underwater Vehicle-Manipulator System (UVMS) is proposed. The proposed controller consists of three terms: a time-delay-estimation term that cancels nonlinearities of the UVMS dynamics, a Terminal Sliding Mode (TSM) term that provides a fast response and a PID term that reduces the tracking error. In addition the proposed controller uses fuzzy rules to adaptively tune the gains...
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Influence of Toll Collection Method on Motorways on Traffic Safety and Efficiency
PublicationThe paper presents the results of the effectiveness analysis for various forms of toll collection on motorway gates and their impact on safety and efficiency of traffic. The results from field tests that were performed on the A1 motorway in Rusocin were used for the analysis. The research included the analysis of the video image of driver behaviour on the way to the toll booths and at toll booths. The PTV VISSIM tool was used to...
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A modern approach to an unmanned vehicle navigation
PublicationA traditional approach to manned vehicles navigation uses a data combined form a variety of navigation sensors like satellite, inertial and time-of-flight. With support of operators perception, chart and sensor, data are analyzed and navigation decisions are made. An unmanned platforms navigation needs an operators support, who is supervising a platforms decision process, basing on navigation data obtained via variety of electronic...
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Hand gesture recognition supported by fuzzy rules and Kalman filters
PublicationThe paper presents a system based on camera and multimediaprojector enabling a user to control computer applications by dynamic hand gestures. Gesture recognition methodology based on representing hand movement trajectory by motion vectors analysed using fuzzy rule-based inference is first given. For effective hand position tracking Kalman filters are employed. The system engineered is developed using J2SE and C++/OpenCV technology....
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Comparison of Two Nonlinear Predictive Control Algorithms for Dissolved Oxygen Tracking Problem at WWTP
PublicationThe wastewater treatment plant is classified as a complex system, due to its nonlinear dynamics, large uncertainty of disturbance inputs, multiple time scales in the internal process dynamics, and multivariable structure. The aeration process, in turn, is an important and expensive part of wastewater treatment plant operation. All operating parameters of the aeration in biological processes are to be precisely controlled to provide...
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Receiver of Doppler multistatic system for moving target detection and tracking
PublicationThe article presents a method for solving major structural problems that occur in the receiver used in the multistatic Doppler system, aimed at determination of the trajectory and velocity of a moving target. In the system two transmitters emit acoustic continuous sinusoidal waves at different frequencies. The signals, scattered from a moving target are received by four hydrophones. Beside of the echoes, much larger signals coming...
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Impact of Volcanic Eruptions on the Occurrence of PAHs Compounds in the Aquatic Ecosystem of the Southern Part of West Spitsbergen (Hornsund Fjord, Svalbard)
PublicationThe paper presents changes in concentration levels of dioxin-like compounds that can be observed over the course of four study seasons in water samples collected from the Arctic watershed of Svalbard. The conducted analysis involved anthropogenic and natural factors that may affect the concentration of PAHs in the study samples of water. An attempt is made to indicate the emission source of the compounds being deposited and to...
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Mechanical properties of concrete mixes M0-M100 concrete mixes
Open Research DataDataset of hardneded properties of concretes containing different amount of magnetite aggregate (M0-M100) mixes.Excel file consists results of:
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Rzadka reprezentacja sygnału niestacjonarnego w technice oszczędnego próbkowania
PublicationPrzedstawiono zastosowanie techniki oszczędnego próbkowania do rekonstrukcji sygnału niestacjonarnego na podstawie skompresowanych próbek w dziedzinie czas-częstotliwość. Zastosowano nadmiarowy algorytm z różnymi słownikami aby znaleźć rzadką reprezentację sygnału. Wyniki symulacji potwierdzają, że zastosowanie oszczędnego próbkowania pozwala na rekonstrukcję sygnału niestacjonarnego z małej liczby losowo pobranych próbek, z niewielką...
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The forming and emission of high power electromagnetic pulses
PublicationAn impulse energy source, a power conditioning system and an electromagnetic field emitter are essential to generate an electromagnetic field pulse (EMFP) with a specific frequency bandwidth. Selected simulation results for a power conditioning system consisting of a fuse opening switch and a paraboloidal electromagnetic emitter have been presented in this article. The synthetic system examined in the simulation is powered by...
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Rigid polyurethane foams modified with selected flame retardants
PublicationThe flame retardants: expandable graphite, triethylphosphatehas been used in rigid polyurethane foams (PUFs). The influence of fillers amounts on processing parameters, physical-mechanical properties (compression strength, density, water absorption, brittleness)and thermal properties (thermal stability) of such foams has been analyzed.The gel, cram and rise time for PUFs modified with flame retardant has been observed during synthesis...
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Wireless intelligent audio-video surveillance prototyping system
PublicationThe presented system is based on the Virtex6 FPGA and several supporting devices like a fast DDR3 memory, small HD camera, microphone with A/D converter, WiFi radio communication module, etc. The system is controlled by the Linux operating system. The Linux drivers for devices implemented in the system have been prepared. The system has been successfully verified in a H.264 compression accelerator prototype in which the most demanding...
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Smaller Representation of Finite State Automata
PublicationThis paper is a follow-up to Jan Daciuk's experiments on space-effcient finite state automata representation that can be used directly for traversals in main memory. We investigate several techniques of reducing memory footprint of minimal automata, mainly exploiting the fact that transition labels and transition pointer offset values are not evenly distributed and so are suitable for compression. We achieve a gain of around 20-30%...