Filtry
wszystkich: 685
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Wyniki wyszukiwania dla: numerical modelling
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Derivation of the scaling laws used in geotechnical centrifuge modelling-application of dimensional analysis and Buckingham Π theorem
PublikacjaGeotechnical centrifuge modelling has been a world-wide used technology in physical tests. In this paper a derivation of scaling laws by dimensional analysis for the centrifugal modelling is presented. Basic principles of centrifuge modelling are described. Scaling laws for slow events like consolidation and fast events like dynamic loads are shown. The differences in scale factors for both processes are noticed. The aim of this...
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Mode choice modelling for urban areas
PublikacjaThe article presents the question of mode choice modelling in a four-stage travel modelling process. The article indicates limitations of currently used simplified methods of mode choice modelling and presents the possibility of using a more detailed approach that accounts for additional, statistically significant factors with the use of advanced mathematical tools, discrete choice models. A need has also been identified to include...
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Biological processes modelling for MBR systems: A review of the state-of-the-art focusing on SMP and EPS
PublikacjaA mathematical correlation between biomass kinetic and membrane fouling can improve the understanding and spread of Membrane Bioreactor (MBR) technology, especially in solving the membrane fouling issues. On this behalf, this paper, produced by the International Water Association (IWA) Task Group on Membrane modelling and control, reviews the current state-of-the-art regarding the modelling of kinetic processes of biomass, focusing on...
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Mathematical modelling and computer simulation of activated sludge systems.Second edition
PublikacjaMathematical Modelling and Computer Simulation of Activated Sludge Systems – Second Edition, provides, from the process engineering perspective, a comprehensive and up-to-date overview regarding various aspects of the mechanistic (“white box”) modelling and simulation of advanced activated sludge systems performing biological nutrient removal. In the new edition of the book, a special focus is given to nitrogen removal and an overview...
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Port-Based Modelling of Distributed-Lumped Parameter Systems
PublikacjaThere in the paper is presented an uniform, port-based approach to modelling of both lumped and distributed parameter systems. Port-based model of the distributed system has been defined by application of bond graph methodology and distributed transfer function method (DTFM). The approach proposed combines versatility of port-based modelling and accuracy of distributed transfer function method. The concise representation of lumped-distributed...
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Modeling of Combined Phenomena Affecting an AUV Stealth Vehicle
PublikacjaIn the paper some results of research connected with modelling the basic stealth characteristics of an AUV vehicle are presented. First of all a general approach to design of the stealth AUV autonomous underwater vehicle under consideration is introduced. Then, the AUV stealth vehicle concept is briefly described. Next a method of modelling of the stealth characteristics is briefly described as well. As an example of the stealth...
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Application of spatial neural simulators of turbine blade rows to fluid flow diagnostics
PublikacjaThis chapter presents the results of neural modelling of fluid flow in steam turbine row. In modelling working conditions of the flow channel varied, thus the aim of the work was to reconstruct the reference state - distributions of velocity, pressure, and losses in flow channel - with high accuracy for fluid flow diagnostics.
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Modelling a 6-dof manipulator using Matlab software
PublikacjaThis paper presents an alternative approach to modelling a revolute robot. The manipulator in question is Kuka KR 16-2. The main problem in robot modelling is a kinematic analysis. The revolute robot consist of six rotary joints (6-DOF) with base, shoulder, elbow and wirst. The kinematics problem is defined as a transformation from the cartesian space to the joint space. The Denavit- Hartenberg (D-H) model of representation was...
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Designing Control and Protection Systems with Regard to Integrated Functional Safety and Cybersecurity Aspects
PublikacjaThis article addresses current problems of risk analysis and probabilistic modelling for functional safety management in the life cycle of safety-related systems. Two main stages in the lifecycle of these systems are distinguished, namely the design and operation. The risk analysis and probabilistic modelling differ in these stages in view of available knowledge and data. Due to the complexity and uncertainty involved, both qualitative...
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Between Descriptive Geometry and CAD 3D
PublikacjaDescriptive geometry provides methods to analyse three-dimensional space through two-dimensional drawings and prepares to create technical documentation. Geometric form of an engineering project is presented by the means of projection methods based on a 3D model, which is present in designer’s imagination. The forthcoming era of Building Information Modelling (BIM) brings changes in the way the engineer works, as the vision is...
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Mainstream shortcut N removal modeling current status and perspectives
PublikacjaThis work gives an overview of the state-of-the-art in modelling of short-cut processes for nitrogen removal in mainstream wastewater treatment and presents future perspectives for directing research efforts in line with the needs of practice. The modelling status for deammonification (i.e., anammox-based) and nitrite-shunt processes is presented with its challenges and limitations. The importance of mathematical models for considering...
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Quasi-discrete modelling of PMSM phase currents in drives with low switching-to-fundamental frequency ratio
PublikacjaThis study proposes a new quasi-discrete approach to modelling the permanent magnet synchronous motor (PMSM). The quasi-discrete modelling reflects the impact of continuous rotor movement, which takes place during a control cycle, on the shape of motor current waveforms. This provides much improvement in current modelling accuracy under inverter low switching-to-fundamental frequency operation. The proposed approach may be used...
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Low cost real time UAV stereo photogrammetry modelling technique – accuracy considerations
PublikacjaThe paper presents accuracy considerations regarding three 3D modelling techniques. The tested new consumer type stereo camera (ZED 3D Stereolabs) has been implemented info an aerial mapping system, on board micro air vehicle MAV) and tested object has been mapped using a real-time photogrammetry with original real-time software application. The evaluated results has been compared with model gained with a state of art unmanned...
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A Review of Hyperelastic Constitutive Models for Dielectric Elastomers
PublikacjaDielectric elastomers are smart materials that are essential components in soft systems and structures. The core element of a dielectric elastomer is soft matter, which is mainly rubber-like and elastomeric. These soft materials show a nonlinear behaviour and have a nonlinear strain-stress curve. The best candidates for modelling the nonlinear behaviour of such materials are hyperelastic strain energy functions. Hyperelastic functions...
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Selected problems of decision making modelling in power engineering
PublikacjaThe paper presents the selected problems of decision making modelling in power engineering specially investment risk evaluation methods. The proposed model can be used in the range programming the development and investing process in power engineering. Decision making problems in power engineering and the evaluation of investment effectiveness in particular are closely related to modelling which relatively accurately reflects...
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Reduced order model of 2d system
PublikacjaA new method of modelling is developed for static and dynamic analysis of two-dimensional elastic bodies. In the analysis, an elastic body is divided into strips. For each one-dimensional strip the reduced modal model is build up. The modal model contains appropriate number of inputs and outputs to connect lumped interaction that occur between strips. Proposed method of modelling enables to obtain more accurate and more simple...
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Voiceless Stop Consonant Modelling and Synthesis Framework Based on MISO Dynamic System
PublikacjaA voiceless stop consonant phoneme modelling and synthesis framework based on a phoneme modelling in low-frequency range and high-frequency range separately is proposed. The phoneme signal is decomposed into the sums of simpler basic components and described as the output of a linear multiple-input and single-output (MISO) system. The impulse response of each channel is a third order quasi-polynomial. Using this framework, the...
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Simulation of the switched reluctance drive system
PublikacjaSwitched reluctance motors (SRM), unlike other types of motors, for their application require a control system and the supply from a power electronic converter. A method of modelling and mathematical model of an SRM in a switched reluctance drive (SRD) system is presented in the paper. Modelling is based on Lagrange's energy method. Coefficients of the Lagrange's equation have been calculated using the finite element method (FEM)....
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An enhanced method in predicting tensile behaviour of corroded thick steel plate specimens by using random field approach
PublikacjaThe present work investigates the possibility of using random field techniques in modelling the mechanical behaviour of corroded thick steel plate specimens. The nonlinear Finite Element method, employing the explicit dynamic solver, is used to analyse the mechanical properties of typical specimens. A material model considering full nonlinearity is used to evaluate the stress-strain response. The influence of major governing parameters...
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Polynomial Chaos Expansion in Bio-and Structural Mechanics
PublikacjaThis monograph presents a probabilistic approach to modelling the mechanics of materials and structures where the modelled performance is influenced by uncertainty in the input parameters. The work is interdisciplinary and the methods described are applied to medical and civil engineering problems. The motivation for this work was the necessity of mechanics-based approaches in the modelling and simulation of implants used in the...
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Polynomial Chaos Expansion in Bio- and Structural Mechanics
PublikacjaThis thesis presents a probabilistic approach to modelling the mechanics of materials and structures where the modelled performance is influenced by uncertainty in the input parameters. The work is interdisciplinary and the methods described are applied to medical and civil engineering problems. The motivation for this work was the necessity of mechanics-based approaches in the modelling and simulation of implants used in the repair...
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Novel Fault Identification for Electromechanical Systems via Spectral Technique and Electrical Data Processing
PublikacjaIt is proposed, developed, investigated, and validated by experiments and modelling for the first time in worldwide terms new data processing technologies, higher order spectral multiple correlation technologies for fault identification for electromechanical systems via electrical data processing. Investigation of the higher order spectral triple correlation technology via modelling has shown that the proposed data processing technology...
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On Applications of Fractional Derivatives in Circuit Theory
PublikacjaIn this paper, concepts of fractional-order (FO) derivatives are discussed from the point of view of applications in the circuit theory. The properties of FO derivatives required for the circuit-level modelling are formulated. Potential problems related to the generalization of transmission line equations with the use of FO derivatives are presented. It is demonstrated that some of formulations of the FO derivatives have limited...
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Development of models for nitrogen-removal processes in subsurface flow constructed wetlands
PublikacjaThis paper summarizes recent progress in modelling approach of subsurface flow constructed wetlands (SSF CWs), focusing on nitrogen removal processes.
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Integrated membrane bioreactors modelling: A review on new comprehensive modelling framework
PublikacjaIntegrated Membrane Bioreactor (MBR) models, combination of biological and physical models, have been representing powerful tools for the accomplishment of high environmental sustainability. This paper, produced by the International Water Association (IWA) Task Group on Membrane Modelling and Control, reviews the state-of-the-art, identifying gaps for future researches, and proposes a new integrated MBR modelling framework. In...
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Ocena zastosowania wybranych reguł wymiany narzędzi w systemie produkcyjnym
PublikacjaIn this paper, an integrated analytical and simulation modelling framework has been developed with the objective to explore total system planning and operational issues. It enables in particular structuring the alternative process flow in manufacturing systems and their extended investigation under different tool exchange rules with limited number of tool inventory. Simulation studies performed with the proposed rules in the environment...
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Simplified saturation modelling in three-leg power transformer for the system stability analisys
PublikacjaThe paper presents a simplified method for modelling non-linearity of the magnetic circuit of the power transformer. The saturation effect is implemented by describing the self and mutual inductances as a function of the magnetic flux. The most important element of this function is the saturation coefficient which is calculated based on transient state during the unloaded transformer switch on. The transformer model is described...
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Relevance of Urban Freight Transport Modelling Towards the Challenges of Urban Freight Policy
PublikacjaThe main objective of this paper is to investigate how recent trends in urban freight transport analysis and modelling are related to urban freight measures set out in Gdynia’s 2016 Sustainable Urban Mobility Plan. Building on the literature a review framework was defined including 1) stakeholders, 2) descriptors, 3) objectives and 4) solution approach applied in freight modelling efforts. It was clear that the implementation...
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Time-series analysis of road safety trends aggregated at national level in Europe for 2000-2010
PublikacjaThe reader will find in this study road safety modelling theory and time-series analysis techniques, applications to long period data of injury accidents and casualities, aggregared at national level
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On constitutive relations in the resultatnt non-linear theory of shells
PublikacjaThe authors summarize their current research in the field of constitutive modelling in the framework of non-linear 6-parameter shell theory. In particular the description of isotropic, multilayered composite and functionally graded shells is presented.
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Modelling and analysis of beam/bar structure by application of bond graphs
PublikacjaThe paper presents an uniform, port-based approach to modelling of beam/bar systems (trusses). Port-based model of such distributed parameter system has been defined by application of the bond graph methodology and the distributed transfer function method (DTFM). The proposed method of modelling enables to formulate input data for computer analysis by application of the DTFM. The constructed computational package enables the frequency...
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Modelling of Mechatronic Systems with Distributed Parameter Components
PublikacjaThe paper presents an uniform, port-based approach to modelling of both lumped and distributed parameter systems. Port-based model of distributed system has been defined by application of the bond graph methodology and the distributed transfer function method (DTFM). The proposed method of modelling enables to formulate input data for computer analysis by application of the DTFM. The computational package for the analysis of complex...
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Design-oriented computationally-efficient feature-based surrogate modelling of multi-band antennas with nested kriging
PublikacjaDesign of modern antenna structures heavily depends on electromagnetic (EM) simulation tools. EM analysis provides reliable evaluation of increasingly complex designs but tends to be CPU intensive. When multiple simulations are needed (e.g., for parameters tuning), the aggregated simulation cost may become a serious bottleneck. As one possible way of mitigating the issue, the recent literature fosters utilization of faster representations,...
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Chapter 2: Modelling and analysis of rotor with magnetic bearing system
PublikacjaThe paper is concerned with rotor magnetic bearing system modelling. Such system is a relatively complex electromechanical system and can be considered as typical mechatronic one. The port-based modelling of physical systems has been used to obtain discrete-continuous model of considered system. Proposed approach enables to obtain reduced low-order lumped parameter representation of the system including gyroscopic interactions....
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A Concept of Freight Traffic Flow Regulations in the City of Gdansk
PublikacjaThis paper presents a review of state-of-art efforts in urban freight transport modelling in the context of their requirements and applicability as a basis for evaluation of city's freight transport policy. Freight transport mirrors all aspects of the city's economic activity and for that reason its proper planning is of extreme importance. However, urban freight system may be considered as the most varied and fragmented element...
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Modelling of the High Speed Multi-Pole Synchronous Generator for Application in More Electric Aircraft Power Systems
PublikacjaIn this paper different models of the synchronous generator are presented. The simulation results compared with the measurements are shown. Certain physical phenomena are included in described models for the porpoise of adequate analysis of the more electric aircraft power system. For different modelling levels, such as functional level or behavioural level, different physical phenomena have been included. Simulation results for...
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A DISCRETE-CONTINUOUS METHOD OF MECHANICAL SYSTEM MODELLING
PublikacjaThe paper describes a discrete-continuous method of dynamic system modelling. The presented approach is hybrid in its nature, as it combines the advantages of spatial discretization methods with those of continuous system modelling methods. In the proposed method, a three-dimensional system is discretised in two directions only, with the third direction remaining continuous. The thus obtained discrete-continuous model is described...
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The Algorithm of Modelling and Analysis of Latent Semantic Relations: Linear Algebra vs. Probabilistic Topic Models
PublikacjaThis paper presents the algorithm of modelling and analysis of Latent Semantic Relations inside the argumentative type of documents collection. The novelty of the algorithm consists in using a systematic approach: in the combination of the probabilistic Latent Dirichlet Allocation (LDA) and Linear Algebra based Latent Semantic Analysis (LSA) methods; in considering each document as a complex of topics, defined on the basis of separate...
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Non-linear FEM analysis of pounding-involved response of buildings under non-uniform earthquake excitation
PublikacjaThe aim of the paper is to show the results of the study investigating the influence of non-uniform earthquake excitation, due to spatial seismic effects connected with the propagation of seismic wave, on the pounding-involved response of two buildings. The three-dimensional non-linear FEM analysis has been conducted using the detailed models of colliding structures. Acceleration records for different structural supports have been...
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Maszyny elektryczne wokół nas. Poszukiwanie dróg do nauczania na kierunku Elektrotechnika Politechniki Gdańskiej = Electrical machines around us. searching for teaching ways at electrical engineering of the Gdansk University of Technology
PublikacjaStreszczenie angielskie: This paper provides a summary of the didactic assumptions, goals and approach concerning the syllabus and description/modelling of electrical machines (EM) for teaching in the field of power electrical engineering at the Gdansk University of Technology. They have been used to write e-text book entitled "Electrical machines around us" that covered the lectures on electrical machines given for the second...
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Finite Element Method Applied in Electromagnetic NDTE: - A Review
PublikacjaThe paper contains an original comprehensive review of finite element analysis (FEA) applied by researchers to calibrate and improve existing and developing electromagnetic non-destructive testing and evaluation techniques, including but not limited to magnetic flux leakage (MFL), eddy current testing, electromagnetic-acoustic transducers (EMATs). Premium is put on the detection and modelling of magnetic field, as the vast majority...
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Mathematical modelling of implant in an operated hernia for estimation of the repair persistence
PublikacjaThis paper presents mathematical modelling of an implanted surgical mesh used in the repair process of the abdominal hernia. The synthetic implant is simulated by a membrane structure. The author provides a material modelling of the implant based on the dense net model appropriate for technical fabrics. The accuracy of the proposed solution is evaluated by comparing the simulations of the dynamic behaviour of the system with the...
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Modelling of dielectric properties of BiNbO4-based microwave ceramics
PublikacjaIn the present paper results of the studies devoted to computer simulations of dielectric response of electroceramics in a frequency domain as well as analysis of the experimental data are given. As an object of investigations BiNbO4-based microwave ceramics was taken. Simulations of the hypothetical impedance response of the ceramic system were performed under assumption of the brick-layer model. A strategy for analysis and modelling...
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Random field modelling of mechanical behaviour of corroded thin steel plate specimens
PublikacjaThe objective of this work is to explore the possibility of corrosion degradation modelling of thin steel plate specimens with the use of random field approach. The mechanical properties are obtained via the nonlinear Finite Element Analysis with the use of an explicit dynamic solver. The fully nonlinear material model is adopted to obtain the proper stress-strain response. Sensitivity analysis considering the main statistical...
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Parametric versus nonparametric modelling of dynamic susceptibility contrast enhanced MRI based data
PublikacjaDynamic tracking of a bolus of a paramagnetic agent (dynamic susceptibility contract - DSC) in MRI (magnetic resonance imaging) measurements is successfully used for assessment of the tissue perfusion and the other features and functions of the brain (i.e. cerebral blood flow - CBF, cerebral blood volume - CBV, mean transit time - MTT). The parametric and nonparametric approaches to the identification of MRI models are presented...
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Effect of vehicle motion stability after impact/crash on traffic safety
PublikacjaThe article presents the application of general stability theory to the study of road traffic stability immediately after an impact (crash, collision). It turns out that when modelling a collision, vehicles can be treated as colliding masses and dynamical systems can be assigned to this phenomenon.
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The Influence of COD Fraction Forms and Molecules Size on Hydrolysis Process Developed by Comparative OUR Studies in Activated Sludge Modelling
PublikacjaThe activated sludge models (ASMs) commonly used by the International Water Association (IWA) task group are based on chemical oxygen demand (COD) fractionations. However, the proper evaluation of COD fractions, which is crucial for modelling and especially oxygen uptake rate (OUR) predictions, is still under debate. The biodegradation of particulate COD is initiated by the hydrolysis process, which is an integral part of an ASM....
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Deterministic versus stochastic modelling of unsaturated flow in a sandy field soil based on dual tracer breakthrough data
PublikacjaThe 216 km2 Neuenhagen Millcreeck catchment can be characterized as a drought sensitive landscape in NE Germany. It is therefore a fundamental human interest to understand how water that fell as precipitation moves through the unsaturated soils and recharges groundwater. Additionally, a better knowledge of nutrient transport from soil to groundwater is important also, especially in landscapes with light sandy soils. For a better...
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Torsional buckling and post-buckling of columns made of aluminium alloy
PublikacjaThe paper concerns torsional buckling and the initial post-buckling of axially compressed thin-walled aluminium alloy columns with bisymmetrical cross-section. It is assumed that the column material behaviour is described by the Ramberg–Osgood constitutive equation in non-linear elastic range. The stationary total energy principle is used to derive the governing non-linear differential equation. An approximate solution of the equation...
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Road Safety Trends at National Level in Europe: A Review of Time-series Analysis Performed during the Period 2000–12
PublikacjaThis paper presents a review of time-series analysis of road safety trends, aggregatedat a national level, which has been performed in the period 2000 – 12 and applied to Europeannational data sets covering long time periods. It provides a guideline and set of best practices inthe area of time-series modelling and identifies the latest methods and applications of nationalroad safety trend analysis...
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Nonlinear Model of Synchronous Generator for Autonomous Electrical Power Systems Analysis
PublikacjaThis paper presents the nonlinear lookup table model for synchronous generator (SG) analysis. The saturation effects of the SG magnetic circuit have been considered. The saturated characteristic of the SG magnetic circuit are based on the open circuit saturation curve for magnetizing inductances. The model has been implemented into the Synopsys/Saber software using the MAST modelling language. To implement the no-load voltage characteristic...
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Model based evaluation of plant improvement at a large wastewater treatment plant (WWTP)
PublikacjaIn this work, the effect of the improvement carried out at a large-scale wastewater treatment plant (WWTP) was evaluated, by means of modelling works, with the aim to determine the influence of the modernization over the process performance. After modernization, the energy consumption due to the aeration decreased about a 20% maintaining the effluent quality. In order to double-check the good effluent quality, modelling works were...
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REVIEW OF CURRENT RESEARCH ON CHITOSAN AS A RAW MATERIAL IN THREE-DIMENSIONAL PRINTING TECHNOLOGY IN BIOMEDICAL APPLICATIONS
PublikacjaThree-dimensional (3D) biomaterial manufacturing strategies show an extraordinary driving force for the development of innovative solutions in the biomedical sector, including drug delivery systems, disease modelling and tissue and organ engineering. Due to its remarkable and promising biological and structural properties, chitosan has been widely studied for decades in several potential applications in the biomedical field. However,...
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Role patterns in IT projects teams - design of a selection module using fuzzy logic techniques
PublikacjaPresented paper introduces an approach based on usage of role patterns and modelling by the use of fuzzy logic tool for selection process with limitation to the area of IT projects environment. The article shows a concept of role patterns structures and their further usage in process of forming a fuzzy model dedicated to candidate assessment process support
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Modelling of blood flow: from macro to microscales
PublikacjaThe aim of this paper it to review various scale approaches to blood flow modelling. Blood motion may be described by three types of mathematical models according to the observed scales or resolutions, namely microscopic, mesoscopic and macroscopic description. The above approaches are discussed together with their advantages and disadvantages. Several results of mesoscopic simulations are presented.
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Respiratory system modelling and simulation basing on the forced oscilation technique
PublikacjaConventional methods of testing lung functioning demand a specific respiratory action of the patient. In contrast, the forced oscillation technique (fot) provides measurements obtained with a minimal cooperation of the subject. The aim of this study is to verify the usefulness of the forced oscillation technique modelling in respiratory system diagnosing. in order to do it two models of fot measurements have been considered: the...
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THE MODELLING OF ACCUMULATION AND DISSIPATION OF ENERGY IN MECHANICAL DRIVE SYSTEM
PublikacjaThis paper presents a modelling of accumulation and dissipation energy in simple drive system. The simple drive system is presented by laboratory stand designed for calculate fatigue life of material for bending and rotation tests pieces. The laboratory stand was prepared to diagnosis of fatigue life of material by use energetic methods. This idea was submitted as utility model to Polish Patent Office. This laboratory stand gives...
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Fractional Order Circuit Elements Derived from Electromagnetism
PublikacjaIn this paper, derivations of fractional-order (FO) circuit-element equations from electromagnetism are presented. Whilst many papers are devoted to FO modelling of electrical circuits, there are no strong foundations for such an approach. Therefore, we investigate relations between the FO electromagnetism and the FO circuit theory. Our derivations start from quasi-static (QS) approximations of Maxwell's equations in media with...
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Improved Uniform Sampling in Constrained Domains for Data-Driven Modelling of Antennas
PublikacjaData-driven surrogate modelling of antenna structures is an attractive way of accelerating the design process, in particular, parametric optimization. In practice, construction of surrogates is hindered by curse of dimensionality as well as wide ranges of geometry parameters that need to be covered in order to make the model useful. These difficulties can be alleviated by constrained performance-driven modelling with the surrogate...
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Selected aspects of customization of cognitive dimensions for evaluation of visual modeling languages.
PublikacjaFor the successful application of diagrams in software engineering, high quality visual modelling languages (VML) are required. There is a need for new effective methodologies of VML evaluation. This paper discusses selected aspects of applying cognitive dimensions as a basis of the evaluation. Then, it briefly presents CD-VML methodology which integrates the cognitive dimensions with a theory of visual modelling languages. Finally,...
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On Non-holonomic Boundary Conditions within the Nonlinear Cosserat Continuum
PublikacjaWithin the framework of the nonlinear micropolar elastic continuum we discuss non-holonomic kinematic boundary conditions. By non-holonomic boundary conditions we mean linear relations between virtual displacements and virtual rotations given on the boundary. Such boundary conditions can be used for modelling of complex material interactions in the vicinity of the boundaries and interfaces.
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Solving Boundary Value Problems for Second Order Singularly Perturbed Delay Differential Equations by ε-Approximate Fixed-Point Method
PublikacjaIn this paper, the boundary value problem for second order singularly perturbed delay differential equation is reduced to a fixed-point problem v = Av with a properly chosen (generally nonlinear) operator A. The unknown fixed-point v is approximated by cubic spline vh defined by its values vi = vh(ti) at grid points ti, i = 0, 1, ... ,N. The necessary for construction the cubic spline and missing the first derivatives at the boundary...
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Toward Mechanosynthesis of diamondoid structures: III. Quantum-chemical study of silylene molecule and silicon atom transfer mechanism from caped SWCNT tip to the reaction center on a hydrogenated Si(111) surface
PublikacjaOpublikowana wcześniej (Modelling Simul. Mater. Sci. Eng., Vol. 7, 1999, pp. 43-58) strategia mechanosyntezy struktur krzemu na uwodornionej płaszczyźnie Si(111) została poszerzona poprzez uwzględnienie ostrza w postaci zamkniętej SWCNT jako urządzenia kontrolującego położenie cząsteczki sililenu oraz atomu krzemu.
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Modelling of pipes conveying flowing liquid
PublikacjaThe paper introduces the method of modal reduction of system which consists of pipe with flowing liquid. The concept of hybrid model is proposed. The system model consists of two parts, the modal model and the finite elements model. The modal model represents linear, self-adjoined part of the system, while simple lumped technique is applied for modelling of Coriolis phenomena.
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Secure access control and information protection mechanisms in radio system for monitoring and acquisition of data from traffic enforcement cameras
PublikacjaThe 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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Computational algorithm for the analysis of mechatronic systems with distributed parameter elements
PublikacjaThe paper presents a systematic computational package for analysis of complex systems composed of multiple lumped and distributed parameter subsystems. The algorithm is based on the transfer function method (DTFM). With this algorithm, a bond graph technique for the modelling is developed to simplify computations. Analysis of different systems requires only changing the inputs data in the form of the bond graph diagram
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The particle method for simulation of self-organization phenomena
PublikacjaThe aim of the work was to design, implement, and use, in a number of experiments, an abstract software environment (an artificial world)suitable for modelling systems consisting of many moving and interactingobjects distributed in space. The environment, named DigiHive, is directed towards modeling of complex systems manifested by processes of self-organization, self-reproduction and self modifications. The environment is mainly...
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Linear viscoelastic modelling of damage-involved structural pounding during earthquakes
PublikacjaDamage-involved structural pounding during earthquakes has been recently intensively studied using different impact force models. The results of the previous studies indicate that the linear viscoelastic model is relatively simple yet accurate in modelling pounding-involved behaviour of structures during earthquakes. The only shortcoming of the model is a negative value of the pounding force occurring just before separation, which...
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The new investing effectiveness evaluation multi-criteria method in modern supply systems
PublikacjaThe important problem in the processes of modelling and programming the development of sustainable energy sector is the multi-criteria manner of assessing the effectiveness of investments. The goal of this paper is to show how to take into account the impact of investments in multidimensional modelling decision-making processes. This goal can be achieved through the development, presentation, and use of a new multi-criteria method...
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Using FreeFEM open software for modelling the vibrations of piezoelectric devices
PublikacjaModelling vibrations of piezoelectric transducers has been a topic discussed in the literature for many decades. The first models - so-called one-dimensional - describe the vibrations only near operating frequency and near its harmonics. Attempts to introduce two-dimensional models were related to the possibility of one transducer working at several frequencies, including both thickness vibrations and those resulting from the transducer...
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Modelling of Abdominal Wall Under Uncertainty of Material Properties
PublikacjaThe paper concerns abdominal wall modelling. The accurate prediction and simulation of abdominal wall mechanics are important in the context of optimization of ventral hernia repair. The shell Finite Element model is considered, as the one which can be used in patient-specific approach due to relatively easy geometry generation. However, there are uncertainties in this issue, e.g. related to mechanical properties since the properties...
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Influence of Added Water Mass on Ship Structure Vibration Parameters in Virtual and Real Conditions
PublikacjaModelling of ship structures in a virtual environment is now standard practice. Unfortunately, many engineers forget to consideri the influence of added water on the frequency values and the amplitude of natural vibrations. The article presents the effect of water damping on the frequency values of the individual natural vibration modes. The tests were carried out in two stages. First, the mentioned values were determined using...
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Adaptive Dynamical Systems Modelling of Transformational Organizational Change: with Focus on Organizational Culture and Organizational Learning
PublikacjaTransformative Organizational Change becomes more and more significant both practically and academically, especially in the context of organizational culture and learning. However computational modeling and a formalization of organizational change and learning processes are still largely unexplored. This paper aims to provide an adaptive network model of transformative organizational change and translate a selection of organizational...
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Adaptive Dynamical Systems Modelling of Transformational Organizational Change with Focus on Organizational Culture and Organizational Learning
PublikacjaTransformative Organizational Change becomes more and more significant both practically and academically, especially in the context of organizational culture and learning. However computational modeling and a formalization of organizational change and learning processes are still largely unexplored. This paper aims to provide an adaptive network model of transformative organizational change and translate a selection of organizational...
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On a Method of Efficiency Increasing in Kaplan Turbine
PublikacjaThis paper presents a method of increasing efficiency in Kaplan-type turbine. The method is based on blade profile optimisation together with modelling the interaction between rotor and stator blades. Loss coefficient was chosen as the optimisation criterion, which is related directly to efficiency. Global optimum was found by means of Genetic Algorithms, and Artificial Neural Networks were utilised for approximations to reduce...
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Modelling of Geared Multi-Rotor System
PublikacjaIn 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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How to model ROC curves - a credit scoring perspective
PublikacjaROC curves, which derive from signal detection theory, are widely used to assess binary classifiers in various domains. The AUROC (area under the ROC curve) ratio or its transformations (the Gini coefficient) belong to the most widely used synthetic measures of the separation power of classification models, such as medical diagnostic tests or credit scoring. Frequently a need arises to model an ROC curve. In the biostatistical...
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Modelling of heat transfer in supercritical pressure recuperators
PublikacjaIn the paper presented is analysis of convective flow heat transfer at supercritical pressure in channels of heat exchanger working in the thermodynamic cycle. The modelling is based on the division of the flow into three regions, namely the heavy fluid, a two phase flow consisting of the heavy and light fluids and finally the light fluid flow. Modelling is concentrated on the region of simultaneous flow of two fluids divided into...
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Advances in analysis, quantification and modelling of N2O emission in SBRs under various DO set points
PublikacjaNitrous oxide (N2O), considered a major greenhouse gas (GHG) in wastewater treatment plants (WWTPs), is produced during both nitrification and denitrification processes; hence, it needs to be controlled by internal and external strategies. Various factors, such as DO, temperature, and pH, could be incorporated into the mitigation of emissions in WWTPs. In this research, potential operational strategies were investigated in order...
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Planning optimised multi-tasking operations under the capability for parallel machining
PublikacjaThe advent of advanced multi-tasking machines (MTMs) in the metalworking industry has provided the opportunity for more efficient parallel machining as compared to traditional sequential processing. It entailed the need for developing appropriate reasoning schemes for efficient process planning to take advantage of machining capabilities inherent in these machines. This paper addresses an adequate methodical approach for a non-linear...
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Business Process Modelling and Enterprise Improvement Analysis
PublikacjaThe main trends in developing an approach and tools for business process modelling are discussed. Business Process Management (BPM) and BPM Notation (BPMN) are presented. Moreover, the possibilities of C2NIWA in a wide range of these tools running on a supercomputer are suggested. Firstly, the company development strategy can be planned . Secondly, quick and flexible changes of its processes can be modelled, analysed and implemented....
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CPLFD-GDPT5: High-resolution gridded daily precipitation and temperature data set for two largest Polish river basins
PublikacjaThe CHASE-PL (Climate change impact assessment for selected sectors in Poland) Forcing Data–Gridded Daily Precipitation & Temperature Dataset–5 km (CPLFD-GDPT5) consists of 1951–2013 daily minimum and maximum air temperatures and precipitation totals interpolated onto a 5 km grid based on daily meteorological observations from the Institute of Meteorology and Water Management (IMGW-PIB; Polish stations), Deutscher Wetterdienst...
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Nonlocal Models of Plates and Shells with Applications in Micro- and Nanomechanics
PublikacjaNowadays, the use of small-scale structures in micro/nanomachines has become more and more widespread. The most important applications of such small-sized parts are in micro-electro-mechanical systems (MEMS) as well as nano-electro-mechanical systems (NEMS) as actuators, sensors, energy harvesters. For example, nanosensors are nanoscale devices that measure physical quantities and convert these to signals that can be detected and...
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G2DC-PL+: a gridded 2 km daily climate dataset for the union of the Polish territory and the Vistula and Odra basins
PublikacjaG2DC-PL+, a gridded 2 km daily climate dataset for the union of the Polish territory and the Vistula and Odra basins, is an update and extension of the CHASE-PL Forcing Data – Gridded Daily Precipitation and Temperature Dataset – 5 km (CPLFD-GDPT5). The latter was the first publicly available, high-resolution climate forcing dataset in Poland, used for a range of purposes including hydrological modelling and bias correction of...
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On various modelling approaches to real-time visualisation of blood flow
PublikacjaThis paper reviews various modelling approaches to real-time visualisation of blood flow. These include classic, macroscale approach based on the momentum conservation equation together with a proper constitutive equation. Moreover, modern micro- and mesoscale approaches, such as molecular dynamics and dissipative particle dynamics, are discussed. Advantages and disadvantages of the discussed methods are highlighted with particular...
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Control of nonlinear and linearized model of self-balancing electric motorcycle
PublikacjaSelf-Balancing Electric Motorcycle (SBEM) is a dynamic and nonlinear electro-mechanical system. In this paper, the process of mathematical modelling and line-arization of SBEM is presented. The model of the control system in Matlab envi-ronment is implemented. The control system using the PID controller is designed. The operation of particular structures of the PID controller on the simulation model is compared. Due to simulation...
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Modelling of Ship’s Heeling and Rolling for the Purpose of Gantry Control Improvement in the Course of Cargo Handling Operations in Sea Ports
PublikacjaThe paper presents two proposals of models of interaction between a ship and cargo being loaded or discharged by a gantry in port, in terms of heeling and rolling of the vessel. The main purpose of such modelling is the need for improvement of gantry control with regard to faster operations thanks to more accurate estimation of level and moment of cargo release from a gantry hook or spreader. The study may be the contribution to...
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[Komentarz do artykułu] Yin, W.-Y., Wu, B., Miao, M., Doi, L.B., Li, L.-W., and Kooi, P.-S.: Experimental characterisation and modelling of on-chip capacitors and resistors on GaAs substrates.
PublikacjaDokonano krytycznej oceny wartości elementów schematu zastępczego rezystorów monolitycznych wykonanych na podłożu GaAs przedstawionych w pracy: Yin, W.-Y., Wu, B., Miao, M., Doi, L.B., Li, L.-W., and Kooi, P.-S.: Experimental characterisation and modelling of on-chip capacitors and resistors on GaAs substrates, IEE Proc. Microw. Antennas and Propag., 2002,149, (1), pp.50-52.
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A methodology for ultimate strength assessment of ship hull girder accounting for enhanced corrosion degradation modelling
PublikacjaThe presented work shows a methodology for the ultimate strength assessment of a ship hull, considering enhanced corrosion modelling. The approach is based on the classical Smith method. However, the recent findings regarding the impact of corrosion degradation on ultimate strength are incorporated. To this end, the stress–strain relationships for particular elements composing ship hull cross-section are modified using a specially...
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Effectiveness of Random Field Approach in Serviceability Limit State Analysis of Strip Foundation
PublikacjaThis work conducts a probabilistic inquiry on how the variability of the parameter defining soil deformability affects the settlement of the foundation located on the soil. The analysis addresses the random foundation model to relevantly estimate the probability of allowable deflection exceedance. The constitutive model parameter is based either on a single random variable or a random field. The computations incorporate direct...
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High-Resolution Wind Wave Parameters in the Area of the Gulf of Gdańsk During 21 Extreme Storms
PublikacjaThis dataset contains the results of wind-wave parameter modelling in the area of the Gulf of Gdańsk (Southern Baltic). For the simulations, a high resolution SWAN model was used. The dataset consists of the significant wave height, the direction of the wave approaching the shore and the wave period during 21 historical, extreme storms. The storms were selected by an automatic search over the 44-year-long significant wave height...
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Simulation model of IPMSM drive with rotor position estimator
PublikacjaThe paper presents a simulation model of electric drive consisting of: IPMSM motor, inverter and digital controller. The model was designed in Mathlab/Simulink. By modelling of the controller its discrete operation was taken into account in order to simulate precisely a specific sensorless control algorithm. A method for estimation of angular rotor position was proposed. Its mathematical algorithm was explained and errors were...
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Modal Reduction and Analysis of Gyroscopic Systems
PublikacjaThe paper introduces the method of the modal reduction of systems that experience the Coriolis acceleration or gyroscopic effect component. In such cases corresponding system equations are non-self-adjoined. To solve the problem modal reduced model is built up for the system without Coriolis acceleration or gyroscopic effect terms. These phenomena are included by application of any lumping technique. Hence, the final reduced model...
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Simulation Model of IMS/NGN with Transport Stratum Based on MPLS Technology
PublikacjaIn the paper we continue our research on traffic modelling in the Next Generation Network (NGN) architecture, which includes the IP Multimedia Subsystem (IMS) elements. A simulation model of a single NGN domain with transport stratum based on the Multiprotocol Label Switching (MPLS) technology is proposed, which allows evaluation of mean response time of this stratum. The simulation model is applied to verify the results obtained...
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A SHORT REVIEW OF BLOOD FLOW MODELLING METHODS: FROM MACRO- TO MICROSCALES
PublikacjaThe aim of this paper it to review various scale approaches to the blood flow modelling. Blood motion may be described by three types of mathematical models according to the observed scales or resolutions, namely microscopic, mesoscopic and macroscopic descriptions. The above approaches are discussed together with their advantages and disadvantages. Several results of mesoscopic simulations are presented with particular attention...
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Intensification of thermal convection near electric devices using flat screens – computer modelling
PublikacjaIntensification of natural thermal convection near electric devices is possible by application of additional elements as screens creating convection canals close to the device. In the earlier authors paper the results of the analysis of thermal convection with the use of only one additional screen close to the electric device were presented. This paper presents computer modelling of thermal convection when two screens near the...
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Modelling Evolution of Knowledge-Based Information Technology Organization: The Concept and Perspective
PublikacjaIncreasing pressure on improving the efficiency of companies' operations leads to transformation of their Information Technology (IT) organizations from technology-oriented to service-oriented, based on the Information Technology Infrastructure Library (ITIL) model. The evolution of these IT organizations can be supported by the knowledge-based systems centered on the rules determined through agregation and refinement of existing...
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Modelling of two-component turbulent mass and heat transfer in air-fed pressurised suits
PublikacjaIn this paper the modelling of an important industrial problem is addressed, which involves the two-component turbulent flow with heat transfer that takes place inside protective clothing. The geometry of the flow boundaries is reconstructed in a CAD system from photogrammetry scan data. The overall model is sufficiently realistic to allow, after validation, design improvements to be tested. Those presented here allow the reduction...
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Performance evaulation of video object tracking algorithm in autonomous surveillance system
PublikacjaResults of performance evaluation of a video object tracking algorithm are presented. The method of moving objects detection and tracking is based on background modelling with mixtures of Gaussians and Kalman filters. An emphasis is put on algorithm's efficiency with regards to its settings. Utilized methods of performance evaluation based on comparison of algorithm output to manually prepared reference data are introduced. The...
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Performance evaluation of video object tracking algorithm in autonomous surveillance system
PublikacjaResults of performance evaluation of a video object tracking algorithm are presented. The method of moving objects detection and tracking is based on background modelling with mixtures of Gaussians and Kalman filters. An emphasis is put on algorithm's efficiency with regards to its settings. Utilized methods of performance evaluation based on comparison of algorithm output to manually prepared reference data are introduced. The...