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Expedited Metaheuristic-Based Antenna Optimization Using EM Model Resolution Management
PublikacjaDesign of modern antenna systems heavily relies on numerical opti-mization methods. Their primary purpose is performance improvement by tun-ing of geometry and material parameters of the antenna under study. For relia-bility, the process has to be conducted using full-wave electromagnetic (EM) simulation models, which are associated with sizable computational expendi-tures. The problem is aggravated in the case of global optimization,...
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Geographic Information System for Flood Hazard Analysis and Early Warning Using Numerical Weather Predictions
PublikacjaFloods are a phenomenon which causes significant losses of lives as well as property damage, which in turn severely impact the local economy. The nature of a flooding has been well researched, and several methods of flood hazard simulation have been established over the last decades. The current legislation in the European Union requires the Member States to create, maintain and update flood risk and hazard maps, as well as identify...
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Efficiency of the Use of LTE System Radio Resources in Highway Transport Enironment
PublikacjaThe paper describes the problem of analysis of throughput-coverage characteristics of the LTE system. Simulation results of the efficiency of the use of LTE radio resources are presented. Simulation studies on the basis of original model of the LTE network simulator were carried out. In addition, the evaluation of throughput for a single connection, and available capacity were evaluated in the context of the use of the same...
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Numerical solution analysis of fractional point kinetics and heat exchange in nuclear reactor
PublikacjaThe paper presents the neutron point kinetics and heat exchange models for the nuclear reactor. The models consist of a nonlinear system of fractional ordinary differential and algebraic equations. Two numerical algorithms are used to solve them. The first algorithm is application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. The second involves building an analog scheme in the FOMCON Toolbox...
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Cost-Efficient Surrogate Modeling of High-Frequency Structures Using Nested Kriging with Automated Adjustment of Model Domain Lateral Dimensions
PublikacjaSurrogate models are becoming popular tools of choice in mitigating issues related to the excessive cost of electromagnetic (EM)-driven design of high-frequency structures. Among available techniques, approximation modeling is by far the most popular due to its versatility. In particular, the surrogates are exclusively based on the sampled simulation data with no need to involve engineering insight or problem-specific knowledge....
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Combining Computational Fluid Dynamics with a Biokinetic Model for Predicting Ammonia and Phosphate Behavior in Aeration Tanks
PublikacjaThe aim of this study was to use computational fluid dynamics for predicting the behavior of reactive pollutants (ammonia and phosphate) in the aerobic zone of the bioreactor located at the Wschod wastewater treatment plant in Gdansk, Poland. The one-dimensional advection-dispersion equation was combined with simple biokinetic models incorporating the Monod-type expressions as source terms for the two pollutants. The problem was...
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Rapid dimension scaling of triple-band antennas by means of inverse surrogate modeling
PublikacjaGeometry scaling of antennas, i.e., finding optimum dimensions of the structure for given operating conditions and material parameters is an important yet challenging problem. In this paper, we discuss fast dimension scaling of triple-band antennas with respect to operating frequencies. We adopt the inverse surrogate modeling approach where the surrogate model is a function of the three operating frequencies of the antenna and...
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Computationally Efficient Design Optimization of Compact Microwave and Antenna Structures
PublikacjaMiniaturization is one of the important concerns of contemporary wireless communication systems, especially regarding their passive microwave components, such as filters, couplers, power dividers, etc., as well as antennas. It is also very challenging, because adequate performance evaluation of such components requires full-wave electromagnetic (EM) simulation, which is computationally expensive. Although high-fidelity EM analysis...
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Practical Approach to Large-Scale Electronic Structure Calculations in Electrolyte Solutions via Continuum-Embedded Linear-Scaling Density Functional Theory
PublikacjaWe present the implementation of a hybrid continuum-atomistic model for including the effects of a surrounding electrolyte in large-scale density functional theory (DFT) calculations within the Order-N Electronic Total Energy Package (ONETEP) linear-scaling DFT code, which allows the simulation of large complex systems such as electrochemical interfaces. The model represents the electrolyte ions as a scalar field and the solvent...
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Ocean mixed layer dynamics: high-resolution simulations of wind, wave and convective effects
Dane BadawczeThis dataset contains results of high-resolution numerical simulations of the ocean mixed layer (OML) forced by wind, waves and cooling from the atmosphere, i.e., under strongly turbulent, convective conditions. The goal is to provide detailed, three-dimensional information about OML circulation, turbulent kinetic energy, and temperature and salinity...
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Simulation and Experiments of High Speed Machining Vibration Monitoring with Variable Spindle Velocity
PublikacjaArtykuł poświęcony jest nadzorowaniu drgań wirujących narzędzi podczas obróbki szybkościowej na nowoczesnych centrach frezarskich. Przeprowadzono analizę dynamiki procesu skrawania smukłym frezem kulistym. W celu zredukowania drgań zastosowano, z powodzeniem, zmienną prędkość obrotową narzędzia. Badania symulacyjne dotyczące efektywności proponowanej metody zostały potwierdzone wynikami badań eksperymentlanych na frezarce Alcera...
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Advanced coating of interior of tanks for rising environmental safety - numerical simulation of grounding
PublikacjaZwiększanie bezpieczeństwa środowiska naturalnego podczas transportu materiałów ropopochodnych stale stanowi ważny i aktualny problem badawczy. W pracy prezentowane są wyniki badań innowacyjnych powłok ochronnych zmniejszających ryzyko rozlewu olejowego podczas kolizji środków transportu - w szczególności statków. Prace badawcze prowadzone były w ramach programu Eureka E!3614 CORET.
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Numerical simulation of the quaternary aquifer groundwater flow of the northern Vistula delta plain
PublikacjaW pracy przedstawiono wyniki obliczeń krążenia wód podziemnych w czwartorzędowym poziomie wodonośnym rejonu Żuław Gdańskich. Czwartorzędowy poziom wodonośny odgrywa najważniejszą rolę w zaopatrzeniu w wodę aglomeracji gdańskiej. W obliczeniach wykorzystano programy Modflow i Modpath zawarte w pakiecie (GMS 3.1). Odtworzono warunki przed uruchomieniem ujecia Lipce wykorzystując obliczenia dla stanu ustalonego krążenia wody w warstwie...
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Half-order analytical modelling of ferromagnetic sheet. Validation with finite elements simulation
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Modelling and simulation analysis of process alternatives in the cellular manufacturing of axially symmetric parts
PublikacjaAnalizowano procesy technologiczne (PT) alternatywnego wytwarzania określonego spektrum przedmiotów (PO) w różnych systemach gniazdowych. Rozpatrzono warianty PT z operacjami zintegrowanej obróbki wiórowej kształtującej i obróbki wykańczającej poprzez nagniatanie, oraz wariantów z różnicowaniem operacji, w których obróbka wykańczająca realizowana jest w oddzielnych operacjach szlifowania. Dla potrzeb gniazdowej dekompozycji systemów...
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Simulation Results of Dynamic Capacity Reallocation in Hierarchical Cell Structure of UMTS Network
PublikacjaIn the paper simulation results of dynamic capacity reallocation between different layers of hierarchical cell structure of UMTS network has been described. This approach for load management seems to be useful for improving the resource utilization perfmorance.
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Simulation Method for Scheduling Linear Construction Projects Using the Learning– Forgetting Effect
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2D numerical simulation of tear film dynamics: Effects of shear-thinning properties
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Adsorption chiller in a combined heating and cooling system: simulation and optimization by neural networks
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Molecular simulation study of cooperativity in hydrophobic association: clusters of four hydrophobic particles
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Cost minimization of locating construction machinery park with the use of simulation and optimization algorithms
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Free Energies of the Disassembly of Viral Capsids from a Multiscale Molecular Simulation Approach
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Computer simulation of current voltage response of elektrocatalytic sensor.Optoelectronic and Electronic Sensors V.
PublikacjaW pracy przedstawiono wyniki symulacji komputerowej działania czujnika elektrokatalitycznego. Do badań wykorzystano program D. Gossera opierający się na metodzie różnic skończonych.
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Numerical simulation of damage detection in rectangular plate by two-dimensional wavelet transform.
PublikacjaW pracy przedstawiono metodę lokalizacji pęknięć w płytach przy zastosowaniu transformaty falkowej.
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Application of the Boundary Element Method for the Simulation of Two-dimensional Viscous Incompressible Flow
PublikacjaThe paper presents the application of an indirect variant of the boundary element method (BEM) to solve the two-dimensional steady flow of a Stokes liquid. In the BEM, a system of differential equations is transformed into integral equations. Thi smakes it possible to limit discretization to the border of the solution. Numerical discretization of the computational domain was performed with linear boundary elements, for which a...
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Coal-derived conductive pavement for winter de-icing: prototype, modeling, and simulation
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Simulation Tests of Working Press Loads under Pre-tensioned Body Conditions
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Numerical Modeling and Simulation of Vehicular Crashes into Three-Bar Metal Bridge Rail
PublikacjaAdvanced finite element (FE) modeling and simulations were performed on vehicular crashes into a three-bar metal bridge rail (TMBR). The FE models of a sedan, a pickup truck, and a TMBR section were adopted in the crash simulations subject to Manual for Assessing Safety Hardware (MASH) Test Level 2 (TL-2) and Test Level 3 (TL-3) requirements. The test vehicle models were first validated using full-scale physical crash tests conducted...
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YADE - An extensible framework for the interactive simulation of multiscale, multiphase, and multiphysics particulate systems
PublikacjaThis contribution presents the key elements of YADE, an extensible open-source framework for dynamic simulations. During the past 19 years, YADE has evolved from "Yet Another Dynamic Engine"' to a versatile multiscale and multiphysics solver, counting a large, active, and growing community of users and developers. The computationally intense parts of the source code are written in C++, using flexible object models that allow for...
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Experiences with computer simulation at two large wastewater treatment plants in northern Poland
PublikacjaPrzedstawiono wyniki symulacji pracy wielofazowych komór osadu czynnego w stanie ustalonym, uzyskanych za pomocą programu GPS-X. Jako dane wejściowe wykorzystano wyniki oznaczeń konwencjonalnych parametrów wykonywanych w trakcie eksploatacji oczyszczalni ścieków "Dębogórze" w Gdyni i "Wschód" w Gdańsku. Jako parametry kontrolne, służące do porównania wyników pomiarów i obliczeń, wykorzystano stężenie ChZT, azotu amonowego, azotanów...
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Modelling and simulation of vibration surveillance during ball end milling of flexible details
PublikacjaPraca dotyczy nadzorowania drgań w procesie frezowania szybkościowego przedmiotów podatnych za pomocą doboru optymalnej prędkości obrotowej wrzeciona. W niestacjonarnym układzie drgającym modelowanym dyskretnie wyodrębniono podukład modalny, podukład strukturalny oraz podukład łączący. Dynamikę procesu skrawania opisano we współrzędnych hybrydowych, przez co uzyskano znacznie mniejszy rząd niż w przypadku modelu strukturalnego....
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Long-term simulation of the activated sludge process at the Hanover-Gümmerwald pilot WWTP
PublikacjaCelem badań było uzyskanie zweryfikowanego modelu ASM3P, który mógłby być wykorzystany jako narzędzie decyzyjne do wyznaczania maksymalnych przepływów w oczyszczalniach ścieków. Symulacje przeprowadzono w oparciu o wyniki badań obciążeń hydraulicznych w pilotowej oczyszczalni ścieków Hanower-Gummerwald. Wyniki symulacji zostały porównane z wynikami pomiarów on-line w komorach osadu czynnego (N-NH4, N-NO3) oraz w odpływie z osadnika...
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Influence of a Radio Frequency on RF Fingerprinting Accuracy Based on Ray Tracing Simulation
PublikacjaIn this paper the influence of a radio signal frequency on performance of Indoor Positioning System based on fingerprinting has been examined using ray-tracing simulations. It has been simulated how spatial distribution of an RF signal strength change with the signal’s frequency. The results were used to show its’ impact on the behavior of localization algorithms that are employing RSS measurements to determine node’s position...
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Rapid Simulation-Driven Multiobjective Design Optimization of Decomposable Compact Microwave Passives
PublikacjaIn this paper, a methodology for fast multiobjective optimization of the miniaturized microwave passives has been presented. Our approach is applicable to circuits that can be decomposed into individual cells [e.g., compact microstrip resonant cells (CMRCs)]. The structures are individually modeled using their corresponding equivalent circuits and aligned with their accurate, EM simulated...
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Molecular dynamics and verisimilitude - to what extent can one trust a computational simulation?
PublikacjaFor the last several tens of years, computer simulations have become of undeniable importance. Molecular Dynamics (MD) simulation techniques are used to examine the phenomena which occur at the level that cannot be observed directly. Thus, they can be successfully exploited in many different scientific fields such as: materials science, applied mathematics and theoretical physics, biochemistry, biophysics or drug design. Despite...
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Objective relaxation algorithm for reliable simulation-driven size reduction of antenna structure
PublikacjaThis letter investigates reliable size reduction of antennas through electromagnetic-driven optimization. It is demonstrated that conventional formulation of the design task by direct footprint miniaturization with imposing constraints on electrical performance parameters may not lead to optimum results. The reason is that—in a typical antenna structure—only a few geometry parameters explicitly determine the antenna footprint,...
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Applying molecular dynamics simulation to take the fracture fingerprint of polycrystalline SiC nanosheets
PublikacjaGraphene-like nanosheets are the key elements of advanced materials and systems. The mechanical behavior of the structurally perfect 2D nanostructures is well documented, but that of polycrystalline ones is less understood. Herein, we applied molecular dynamics simulation (MDS) to take the fracture fingerprint of polycrystalline SiC nanosheets (PSiCNS), where monocrystalline SiC nanosheets (MSiCNS) was the reference nanosheet....
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Analysis of hull, propeller and engine interactions in regular waves by a combination of experiment and simulation
PublikacjaAnalysis of hull, propeller and engine interactions in regular waves by a combination of experiment and simulation
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Nonlinear numerical simulation of earthquake-induced pounding between timber frame buildings
PublikacjaEarthquakes may induce serious dynamic loads acting on buildings, which can lead to damage or even destruction of the whole structure. In densely populated areas, it is quite common that buildings are located very close one to another which can result in pounding between them during ground motions. Due to the environmental awareness, multi-story timber frame buildings are gaining popularity and therefore there is a need to investigate...
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Numerical simulation of natural convection of Glycol-Al2O3 nanofluids from a horizontal cylinder
PublikacjaThis paper deals with natural convection around a circular cylinder with constant heat flux in a cavity using computational fluid dynamics. As fluids ethylene glycol and a mixture of ethylene glycol with Al2O3 nanoparticles (mass concentrations of nanoparticles: 0.1% and 1%) are chosen. Rayleigh number ranges from 3104 to 3105. The nanofluids are modeled with single-phase approach. For the investigated range of nanoparticle concentration, the...
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Expedited simulation-driven design optimization of UWB antennas by means of response features
PublikacjaIn this work, a method for fast design optimization of broadband antennas is considered. The approach is based on a feature-based optimization (FBO) concept where reflection characteristics of the structure at hand are formulated in terms of suitably defined feature points. Redefinition of the design problem allows for reducing the design optimization cost, because the dependence of feature point coordinates on antenna dimensions...
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Simulation of ship turning circle test for ballast and full load conditions
Dane BadawczeThe data show the results of the turning circle spiral test for the simplified ship model, taking into account two states of loading: ballast and full load. During the circulation test, the manoeuvrability of the vessel is tested.
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Analysis of cyclone separator solutions depending on SEC outlet conditions in nCO2PP
PublikacjaUtilization of spray ejector condenser in order to carry out direct-contact condensation of vapour with inert gas (CO2) on a spray of subcooled liquid integrated with separator (to make pure CO2) has been proposed for the task of condensation and CO2 separation in the negative CO2 emission gas power plant. Condensation and separation has a significant impact on the thermodynamic efficiency of the entire negative CO2 emission gas...
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Modeling energy consumption of parallel applications
PublikacjaThe paper presents modeling and simulation of energy consumption of two types of parallel applications: geometric Single Program Multiple Data (SPMD) and divide-and-conquer (DAC). Simulation is performed in a new MERPSYS environment. Model of an application uses the Java language with extension representing message exchange between processes working in parallel. Simulation is performed by running threads representing distinct process...
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Mechatronic Design Towards Investigation of the Temporo-Mandibular Joint Behaviour
PublikacjaA significant problem of the temporo-mandibular joint (TMJ) research is lack of data concerning geometry and position of TMJ discs. It leads to necessity of developing a driving method of the process optimization, which is based on chosen techniques of mechatronic design. In particular, the latter concerns a technique of experimentally supported virtual prototyping. On this stage, the research is characterized by well-verified...
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Adjusted SpikeProp algorithm for recurrent spiking neural networks with LIF neurons
PublikacjaA problem related to the development of a supervised learning method for recurrent spiking neural networks is addressed in the paper. The widely used Leaky-Integrate-and-Fire model has been adopted as a spike neuron model. The proposed method is based on a known SpikeProp algorithm. In detail, the developed method enables gradient descent learning of recurrent or multi-layer feedforward spiking neural networks. The research included...
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Laboratory Load Model Based on 150 kVA Power Frequency Converter and Simulink Real-Time – Concept, mplementation, Experiments
PublikacjaFirst section of the paper provides technical specification of laboratory load model basing on 150 kVA power frequency converter and Simulink Real-Time platform. Assumptions, as well as control algorithm structure is presented. Theoretical considerations based on criteria which load types may be simulated using discussed laboratory setup, are described. As described model contains transformer with thyristor-controlled tap changer,...
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Analysis of IMS/NGN call processing performance using G/G/1 queuing systems approximations
PublikacjaThe paper concerns the Next Generation Network (NGN), which is standardized for distribution of multimedia services based on the IP Multimedia Subsystem (IMS). To guarantee quality, accurate traffic models of IMS/NGN should be proposed. In the paper we compare results obtained with our analytical and simulation model of a single IMS/NGN domain, where various queuing systems are used in the analytical model (M/G/1 and approximations...
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A comprehensive approach to double inverted pendulum modelling
PublikacjaThe problem of mathematical modelling and indication of properties of a DIP has been investigated in this paper. The aim of this work is to aggregate the knowledge on a DIP modelling using the Euler-Lagrange formalism in the presence of external forces and friction. To indicate the main properties important for simulation, model parameters identification and control system synthesis, analytical and numerical tools have been used....
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Designing acoustic scattering elements using machine learning methods
PublikacjaIn the process of the design and correction of room acoustic properties, it is often necessary to select the appropriate type of acoustic treatment devices and make decisions regarding their size, geometry, and location of the devices inside the room under the treatment process. The goal of this doctoral dissertation is to develop and validate a mathematical model that allows predicting the effects of the application of the scattering...