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Search results for: multi-equation models
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Expedited Yield Optimization of Narrow- and Multi-Band Antennas Using Performance-Driven Surrogates
PublicationUncertainty quantification is an important aspect of engineering design, also pertaining to the development and performance evaluation of antenna systems. Manufacturing tolerances as well as other types of uncertainties, related to material parameters (e.g., substrate permittivity) or operating conditions (e.g., bending) may affect the antenna characteristics. In the case of narrow- or multi-band antennas, this usually leads to...
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Empirical verification in industrial conditions of fracture mechanics models of cutting power prediction
PublicationA comparison of experimental results obtained in the industrial conditions at a sawmill located in the Baltic Natural Forest Region (PL) and theoretical cutting power consumption forecasted with the models which include work of separation (fracture toughness) in addition to plasticity and friction has been described. In computations of cutting power consumption during rip sawing of Scots pine wood (Pinus sylvestris L.) values of...
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Can we rely on the pulse transit time - pressure relationship - models comparison
PublicationAn unobtrusive, noninvasive and continuous pressure measurement is invaluable however, still being under research and development. There are many attempts proposing an appropriate relationship between pulse pressure velocity and pressure. Fifteen different formulas, both theoretical and experimental, describing relation between blood pressure and crosssectional area of the vessel were examined. Using these formulas the relation...
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Improving the Accuracy of Automatic Reconstruction of 3D Complex Buildings Models from Airborne Lidar Point Clouds
PublicationDue to high requirements of variety of 3D spatial data applications with respect to data amount and quality, automatized, effcient and reliable data acquisition and preprocessing methods are needed. The use of photogrammetry techniques—as well as the light detection and ranging (LiDAR) automatic scanners—are among attractive solutions. However, measurement data are in the form of unorganized point clouds, usually requiring transformation...
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Modelling of the High Speed Multi-Pole Synchronous Generator for Application in More Electric Aircraft Power Systems
PublicationIn 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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Multi-criteria Differential Evolution for Optimization of Virtual Machine Resources in Smart City Cloud
PublicationIn a smart city, artificial intelligence tools support citizens and urban services. From the user point of view, smart applications should bring computing to the edge of the cloud, closer to citizens with short latency. However, from the cloud designer point of view, the trade-off between cost, energy and time criteria requires the Pareto solutions. Therefore, the proposed multi-criteria differential evolution can optimize virtual...
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A Method for the Evaluation of Urban Freight Transport Models as a Tool for Improving the Delivery of Sustainable Urban Transport Policy
PublicationThe article presents a method which helps local authorities to evaluate urban freight transport models. Given the complex requirements for input data and the inability to supply them for most cities, a proper quantitative evaluation of model functionality may be quite difficult for local authorities. Freight transport models designed to support sustainable urban freight transport objectives are a particular example. To overcome...
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Multi-Beam Antenna for Ka-Band CubeSat Connectivity Using 3-D Printed Lens and Antenna Array
PublicationIn this paper, the design of a passive multi-beam lens antenna is proposed for the CubeSat space communication system as an alternative application of a 2-D microstrip antenna array that has originally been designed for a 39 GHz 5 G MU-MIMO system. The half-ellipsoid lens is 3-D printed using stereolithography (SLA) technology. The antenna prototype is capable of selecting the main beam between 16 different directions with a gain...
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Data set generation at novel test-rig for validation of numerical models for modeling granular flows
PublicationSignificant effort has been exerted on developing fast and reliable numerical models for modeling particulate flow; this is challenging owing to the complexity of such flows. To achieve this, reliable and high-quality experimental data are required for model development and validation. This study presents the design of a novel test-rig that allows the visualization and measurement of particle flow patterns during the collision...
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Hybrid of Neural Networks and Hidden Markov Models as a modern approach to speech recognition systems
PublicationThe aim of this paper is to present a hybrid algorithm that combines the advantages ofartificial neural networks and hidden Markov models in speech recognition for control purpos-es. The scope of the paper includes review of currently used solutions, description and analysis of implementation of selected artificial neural network (NN) structures and hidden Markov mod-els (HMM). The main part of the paper consists of a description...
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Fast EM-driven optimization using variable-fidelity EM models and adjoint sensitivities
PublicationA robust and computationally efficient technique for microwave design optimization is presented. Our approach exploits variable-fidelity electromagnetic (EM) simulation models and adjoint sensitivities. The low-fidelity EM model correction is realized by means of space mapping (SM). In the optimization process, the SM parameters are optimized together with the design itself, which allows us to keep the number...
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A comparative analysis of the effectiveness of corporate bankruptcy prediction models based on financial ratios: Evidence from Colombia, 2008 to 2015
PublicationLogit and discriminant analyses have been used for corporate bankruptcy prediction in several studies since the last century. In recent years there have been dozens of studies comparing the several models available, including the ones mentioned above and also probit, artificial neural networks, support vector machines, among others. For the first time for Colombia, this paper presents a comparative analysis of the effectiveness...
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Mariusz Figurski prof. dr hab. inż.
PeopleMariusz Józef Figurski (born 27 April 1964 in Łasinie, Poland) - Polish geodesist, professor of technical sciences, professor at the Gdańsk University of Technology. Early life and education He passed the matriculation examination in 1983 after he had finished Jan III Sobieski High school in Grudziądz. He graduated the Military University of Technology on an individual mode at the Faculty of Electromechanics and Civil Engineering...
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On Nature-Inspired Design Optimization of Antenna Structures Using Variable-Resolution EM Models
PublicationNumerical optimization has been ubiquitous in antenna design for over a decade or so. It is indispensable in handling of multiple geometry/material parameters, performance goals, and constraints. It is also challenging as it incurs significant CPU expenses, especially when the underlying computational model involves full-wave electromagnetic (EM) analysis. In most practical cases, the latter is imperative to ensure evaluation reliability....
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Multi-region fuzzy logic controller with local PID controllers for U-tube steam generator in nuclear power plant
PublicationIn the paper, analysis of multi-region fuzzy logic controller with local PID controllers for steam generator of pressurized water reactor (PWR) working in wide range of thermal power changes is presented. The U-tube steam generator has a nonlinear dynamics depending on thermal power transferred from coolant of the primary loop of the PWR plant. Control of water level in the steam generator conducted by a traditional PID controller...
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Multiple jets impingement – numerical analysis by the ζ-f and hybrid VLES turbulence models
PublicationPresented paper summarizes the Authors findings referring to the numerical analyses of the jet impinging phenomena in the case of complex jets configurations in various applications e.g. in the heat exchangers. Multiple jets interference resulting in the cross-flow and the surface curvature are the factors which impose the need of advanced turbulence models utilization. The outcome of the research based on the ζ-f turbulence model...
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Multi-criteria Robot Selection Problem for an Automated Single-Sided Lapping System
PublicationFlat lapping is a crucial process in a number of precision manufacturing technologies. Its aim is to achieve extremely high flatness of the workpiece. Single-sided lapping machines have usually standard kinematic systems and are used in conjunction with conditioning rings, which are set properly be-tween the center and the periphery of the lapping plate. In this paper, instead of conventional single-side lapping machine, an automated...
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Global Value Chains and Wages: Multi-Country Evidence from Linked Worker-Industry Data
PublicationThis paper uses a multi-country microeconomic setting to contribute to the literature on the nexus between production fragmentation and wages. Exploiting a rich dataset on over 110,000 workers from nine Eastern and Western European countries and the United States, we study the relationship between individual workers’ wages and industry ties into global value chains (GVCs). We find an inverse (but weak) relationship between the...
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Expedited two-objective dimension scaling of compact microwave passives using surrogate models
PublicationGeometry scaling of compact microwave structures is a challenging problem because of complex relationships between the physical dimensions and electrical characteristics, mostly caused by considerable cross-couplings in densely arranged layouts. Here, a procedure for expedited dimension scaling of compact microwave couplers with respect to two independent criteria has been presented. Our approach involves inverse surrogate models...
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Domain segmentation for low-cost surrogate-assisted multi-objective design optimisation of antennas
PublicationAbstract: Information regarding the best possible design trade-offs of an antenna structure can be obtained through multiobjective optimisation (MO). Unfortunately, MO is extremely challenging if full-wave electromagnetic (EM) simulation models are used for performance evaluation. Yet, for the majority of contemporary antennas, EM analysis is the only tool that ensures reliability. This study introduces a procedure for accelerated...
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Constrained multi-objective optimization of compact microwave circuits by design triangulation and pareto front interpolation
PublicationDevelopment of microwave components is an inherently multi-objective task. This is especially pertinent to the design closure stage, i.e., final adjustment of geometry and/or material parameters carried out to improve the electrical performance of the system. The design goals are often conflicting so that the improvement of one normally leads to a degradation of others. Compact microwave passives constitute a representative case:...
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Torque Transmitted by Multi-plate Wet Clutches in Relation to Number of Friction Plates and Their Dimensions
PublicationIn the paper results of experimental tests on multi-plate wet clutch torque capacity for various diameters and numbers of friction plates are presented. Construction of an apparatus for laboratory tests of wet clutch engagement, drag torque and maximum torque is shown. Methodology of maximum torque capacity experiment and hydraulic circuit diagram, which supplies a motor and an actuator for the experiment are described. Analytically...
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Fast EM-Driven Nature-Inspired Optimization of Antenna Input Characteristics Using Response Features and Variable-Resolution Simulation Models
PublicationUtilization of optimization technique is a must in the design of contemporary antenna systems. Often, global search methods are necessary, which are associated with high computational costs when conducted at the level of full-wave electromagnetic (EM) models. In this study, we introduce an innovative method for globally optimizing reflection responses of multi-band antennas. Our approach uses surrogates constructed based on response...
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Methodology of research on the impact of ramp metering on the safety and efficiency of road traffic using transport models
PublicationThe methods currently used to assess the impact of Intelligent Transport Systems (ITS) services on traffic safety and efficiency are mainly based on expert assessments, statistical studies or traffic models that need further development. There is no structured, uniform evaluation method to compare the impact of different ITS services and their different configurations. The impact of ITS deployment on the road network adjacent to...
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Improved-Efficacy EM-Based Antenna Miniaturization by Multi-Fidelity Simulations and Objective Function Adaptation
PublicationThe growing demands for integration of surface mount design (SMD) antennas into miniatur-ized electronic devices have been continuously imposing limitations on the structure dimen-sions. Examples include embedded antennas in applications such as on-board devices, picosatel-lites, 5G communications, or implantable and wearable devices. The demands for size reduction while ensuring a satisfactory level of the electrical and field...
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Transplantable Melanomas in Hamsters and Gerbils as Models for Human Melanoma. Sensitization in Melanoma Radiotherapy—From Animal Models to Clinical Trials
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Enhancement of lift and drag performances of a NACA0012 airfoil by multi-DBD plasma actuator with additional floating interelectrodes
PublicationIt is clear that the improvement of aircraft aerodynamic performances is currently and will continue to be a significant area of research for the aeronautical industry. The current study is focused on theenhancement of aerodynamic airfoil performances by using a multi-DBD plasma actuator mounted around the model leading-edge. Experiments have been conducted at the University of Orleans, in the 2 m x 2 m test section of a large...
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Mathematical Models of Control Systems of Angular Speed of Steam Turbines for Diagnostic Tests of Automatic and Mechatronic Devices
PublicationAccurate modeling of physical processes of many automatics and mechatronics systems is often necessity. In power system such a process is control of angular velocity of power objects during connection to operation in parallel. This process is extremely dynamic. For this reason response of control system depends from changes of many physical parameters (temperature, pressure and flow of the medium, etc.). Precision modeling influences...
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Fault detection and diagnostics of complex dynamic systems using Gaussian Process Models - nuclear power plant case study
PublicationThe article examines the use of Gaussian Process Models to simulate the dynamic processes of a Pressurized Water nuclear Reactor for fault detection and diagnostics. The paper illustrates the potential of Gaussian Process Models as a tool for monitoring and predicting various fault conditions in Pressurized Water nuclear Reactor power plants, including reactor coolant flow and temperature variations, deviations from nominal working...
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Rapid Multi-band Patch Antenna Yield Estimation Using Polynomial Chaos-Kriging
PublicationYield estimation of antenna systems is important to check their robustness with respect to the uncertain sources. Since the Monte Carlo sampling-based real physics simulation model evaluations are computationally intensive, this work proposes the polynomial chaos-Kriging (PC-Kriging) metamodeling technique for fast yield estimation. PC-Kriging integrates the polynomial chaos expansion (PCE) as the trend function of Kriging metamodel...
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Chosen aspects of skeletal system modeling: Numerical solid and shell models of femur part
PublicationThe purpose of this paper is to present a new method of femur part modeling by using the finite element method. This method treats a femur part as a system composed of cortical and trabecular bone. For the purpose of determining a proper shape of femur part model there were created three models: a) the first one describes a femur part as a solid structure; b) the second one describes a femur part as a connection of cortical bone...
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Exploring governance among social co-operatives: three models from Poland
PublicationThere has been overly interest regarding social enterprise and social entrepreneurship in theory and practice. In this paper the author introduces the workings of governance of small social enterprises i.e. social co-operatives, acting in most cases for the purpose of work and social integration of the marginalized, at the bottom of the pyramid of socio-economic system. The aim of this paper is to provide insights into under researched...
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Multi-objective design optimization of antenna structures using sequential domain patching with automated patch size deter-mination
PublicationIn this paper, a simple yet efficient and reliable technique for fully automated multi-objective design optimization of antenna structures using sequential domain patching (SDP) is discussed. The optimization procedure according to SDP is a two-step process: (i) obtaining the initial set of Pareto-optimal designs representing the best possible trade-offs between considered conflicting objectives, and (ii) Pareto set refinement...
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Multi-stage magnetic-fluid seals for operating in water - life test procedure, test stand and research results. Part II Results of life tests of multi-stage magnetic - fluid seal operating in water
PublicationThe edge criteria for magnetic-fluid seals durability research were described in previous article [24] and now the tests results are presented. The tests were made with three magnetic fluids using various magnets quantity in magnetic assemblies. If values obtained in the repeated test deviated by more than 10 % from results of the first test an additional control test was made for final characteristics. The characteristics are:...
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The Application of a Multi-Criteria Decision-Making for Indication of Directions of the Development of Renewable Energy Sources in the Context of Energy Policy
PublicationThis paper presents the application of multi-criteria decision-making (MCDM) for evaluating what technologies using renewable energy sources (RES) for electricity production have the chance to develop in Poland under the current socio-economic conditions. First, the Analytical Hierarchy Process (AHP) method was used to determine the weights of the optimization criteria. Five main criteria and 30 sub-criteria were identified. Next,...
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A multi-criteria decision model for the introduction of electric storage multiple units on the partially electrified Gdynia-Hel railway
Publication: In this article a multi-criteria study of the use of independently powered electric multiple units on the partially electrified Gdynia Główna - Hel line was carried out. The use of (currently used) diesel and, as an alternative, electric and electric multiple units with an electric energy storage was considered. The analysis was carried out on the basis of three criteria for assessing the route service options, i.e. environmental,...
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Trust Models for Community- Aware Identity Managment. [....]
PublicationArtykuł przedstawia możliwości budowania zaufania pomiędzy członkami społecznych sieci współpracujacych w Internecie. Przedstawiono system informatyczne wykorzystującyna współczesą wiedzę z zakresu psychologi społecznej, umozliwiajacy tworzenie sieci społecznych w internecie.
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Reduced-order models in the finite element analysis
PublicationA novel technique of incorporating macromodels into finite element electromagnetic analysis of waveguide components is presented. Macromodels are generated by using a model order reduction algorithm (ENOR), which results in significant decrease of the number of variables, that describe the computational region. Proposed technique allows for using a few independent macromodels as well as to duplicating one macromodel in many subregions...
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Dressing method in matter + radiation quantum models
PublicationRozważane są modele typu Dicka i Jaynes-Cummings'a, i obliczono widmo zaburzonego modelu Dicka. Wyprowadzono równania łańcuchowe ubierania.
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A digital cartographic source for numerical models in hydrology
PublicationAutorzy prowadzą analizę wykorzystania i przydatności cyfrowych danych kartograficznych w rozwiązywaniu przestrzennych zagadnień hydrologicznych. Szczególne znaczenie dla prowadzonych analiz mają DTM i DEM. Są one źródłem bezpośrednich wielkości wejściowych modelu hydrologicznego i dodatkowo pozwalają na szersze możliwości prezentacji otrzymanego rozwiązania.
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Interpretation of Structural Parameters for Models with Spatial Autoregression
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Towards eddy-resolving models of the Arctic Ocean
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Workload Assessment Predictability for Digital Human Models
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Evolution of models for sorption of PAHs and PCBs on geosorbents.
PublicationWiedza o tym gdzie są zlokalizowane zanieczyszczenia obecne w osadzie oraz z jaką siłą związane są one z osadem jest niezbędna do oszacowania stopnia i skuteczności procesów remediacjyjnych oraz określenia dostępności, mobilności i toksyczności osadów. Dlatego, aby zrozumieć i poznać procesy zachodzące w tak skomplikowanej matrycy, jaką stanowią osady denne/gleby konstruowane są teoretyczne modele matematyczne opisujące prawdopodobny...
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Multiobjective Newsvendor Models with CVaR for Flower Industry
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Low-Cost Surrogate Models for Microwave Filters
PublicationA novel low-cost kriging-based multivariable parametric macromodeling technique for microwave filters is presented. Kriging is used to model both the residues and poles of a microwave filter's reflection coefficient, and the zeros of the transmission coefficient. The proposed residue-pole-zero (RPZ) technique is demonstrated to efficiently model a high dimensional (8D) microwave filter with pseudoelliptic characteristics.
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Coarse-Grained Models of Proteins: Theory and Applications
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Hierarchical random models in road transport safety
PublicationIn this paper multilevel approach to the issue of road safety level on the road network of European regions, classified as NUTS 2 in statistical databases of the EU, has been presented. The risk calculated as the number of death casualties in road accidents per 100,000 inhabitants of a given region has Poisson distribution. Therefore, generalized Poisson model has been assumed in the modelling process. Multilevel stochastic analysis...
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Method of lines for physiologically structured models with diffusion
PublicationWe deal with a size-structured model with diffusion. Partial differential equations are approximated by a large system of ordinary differential equations. Due to a maximum principle for this approximation method its solutions preserve positivity and boundedness. We formulate theorems on stability of the method of lines and provide suitable numerical experiments.
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Alcohol dehydrogenase and its simple inorganic models
PublicationW pierwszej części pracy przeglądowej przedstawiono aktualny stan wiedzy nt mechanizmu działania zależnej od cynku dehydrogenazy alkoholowej. Następnie omówiono dane strukturalne i spektroskopowe uzyskane przy pomocy prostych związków modelowych - na ogół tiolanów cynku i niektórych innych metali przejściowych. Opisano również próby zastosowania prostych kompleksów nieorganicznych naśladujących budowę miejsca aktywnego dehydrogenazy...