Filters
total: 3444
filtered: 3102
-
Catalog
Chosen catalog filters
displaying 1000 best results Help
Search results for: FDTD SIMULATIONS
-
Probabilistic limit state analysis of framed structures. The Monte Carlo simulation.
PublicationW pracy opisano koncepcję rozkładu prawdopodobieństwa stanu granicznego konstrukcji. Koncepcja ta oparta jest na problemowo zorientowanej procedurze symulacyjnej Monte Carlo. Niezawodnosć lub prawdopodobieństwo awarii układu oblicza się na podstawie rozkładu prawdopodobieństwa stanu granicznego.
-
Probabilistic limit state analysis of framed structures. The Monte Carlo simulation.
PublicationW pracy opisana jest koncepcja rozkładu prawdopodobieństwa stanu granicznego konstrukcji, oparta na specjalnej procedurze symulacyjnej Monte Carlo. Główną ideę stanowi obliczenie mnożnika obciażenia granicznego w każdym kroku symulacyjnym. Niezawodnosć lub prawdopodobieństwo awarii konstrukcji sa charakterystykami rozkładu prawdopopdobieństwa stanu granicznego. Szczegółowo opisano dwa warianty symulacji.
-
Coarse-grained simulation - an efficient approach for studying motions of large proteins
PublicationOne of the most important challenges in performing Molecular Dynamics (MD) simulations of large protein complexes is to accommodate the model accuracy and the simulation timescale. Hitherto, for the most relevant dynamics of protein aggregates in an explicit aqueous environment, the timescale reachable for the all-atoms simulations is of hundreds of nanoseconds. This range is four to six orders of magnitude smaller than processes...
-
Possible uses of crisis situation aiding system in virtual world simulation
PublicationMany of the real world crisis situations like spreading fire, hostile units attack, flood, and etc. are commonly used in computer games where a simulation of extensive virtual world is crucial. This paper presents some ideas for possible uses of existing crisis situation aiding system in such environments. Moreover it shows how this kind of system can be taught during subsequent games with a large number of players.
-
Conditional random field simulation of ground motions for large shell structures.
PublicationZaprezentowano metodę stochastycznego modelowania efektu propagacji fali trzęsienia ziemi i analizowano wpływ tego efektu na konstrukcje powłokowe znacznych rozmiarów. Symulowane przy użyciu tej metody rejestry trzęsień ziemi w wybranych punktach podporowych mogą być wykorzystane do analizy dynamicznej zachowania się konstrukcji. Przykładem analizowanej konstrukcji budowlanej jest zbiornik cylindryczny o średnicy 100 m.
-
Numerical simulation of a thin-walled beam with warping stiffeners undergoing torsion
PublicationW pracy rozwinięto koncepcję zastosowania superelementów węzłowych do modelowania stężeń konstrukcyjnych w belkach cienkościennych. Przeprowadzono analizę pracy belek cienkościennych o bisymetrycznym przekroju otwartym ze stężeniami bimomentowymi w formie przepon i przewiązek.
-
Numerical simulation of behaviour of thin-walled frames subjected to static loads
PublicationArtykuł poświęcony jest problemowi zachowania się ramy, zbudowanej z elementów cienkościennych o przekroju bisymetrycznym obciążonej momentem skręcającym.
-
Simulation Model of IMS/NGN with Transport Stratum Based on MPLS Technology
PublicationIn 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...
-
A structure and simulation-driven design of compact CPW-fed UWB antenna
PublicationIn this letter, a structure of a miniaturized ultra-wideband CPW-fed antenna and its design proce-dure are presented. The antenna is a modified version of the design previously proposed in the literature, with additional degrees of freedom introduced in order to improve the structure flexibility. The small size is achieved by executing a rigorous optimization procedure that consists of two stages: (i) smart random search carried...
-
Hybrid Fuzzy-Ontological Project Framework of a Team Work Simulation System
PublicationThe aim of this article is to present the project framework for constructing a Software Process Simulation Modeling (SPSM) system. SPSM systems can be used as a virtual environment for the selection of methods and tools of project management in IT support organizations. The constructed system simulates the Scrum methodology, including the management processes and the project roles. For the implementation of Scrum processes, the...
-
Fast simulation-driven design optimization of UWB band-notch antennas
PublicationIn this letter, a simple yet reliable and automated methodology for rapid design optimization of ultra-wideband (UWB) band-notch antennas is presented. Our approach is a two-stage procedure with the first stage focused on the design of the antenna itself, and the secondstage aiming at identification of the appropriate dimensions of the resonator with the purpose of allocating the band-notch in the desired frequency range. For the...
-
Simulation of influence of the air gap asymmetryon voltage waveforms of a synchronous machine
PublicationResults of simulation of a synchronous generator with the air gap asymmetry characterised by eccentricity are presented in the paper. The Lagrange's energy method has been used in derivation of the model equations. Analysis of influence of the air gap asymmetry on characteristics of self and mutual inductances of windings, as well as analysis of induced voltage waveforms as a function of the air gap asymmetry have been performed....
-
Simulation studies of process flow with in-line part inspection in machining cells
PublicationRozwinięto koncepcję zintegrowanego planowania i sterowania przebiegiem procesu w zrobotyzowanym elastycznym gnieździe obróbkowym (EGO)z maszyną współrzędnościową, realizującą funkcje pomiaru i kontroli wytwarzanych przedmiotów. Analizowano współzależności heurystycznych planów kontroli oraz stosowanych algorytmów szeregowania operacji procesów technologicznych wg określonych scenariuszy, z zastosowaniem programowalnych modeli...
-
Research of Emergency Modes of Wind Power Plants Using Computer Simulation
PublicationThe aim of this study is to investigate changes in the wind power plant energy production parameters under the conditions of sudden wind changes and voltage drop. To achieve these goals, a simulation of operation of wind power plants was performed. Twelve wind turbines with variable rotational speed equipped with a Fuhrländer FL 2500/104 asynchronous double-fed induction generator (DFIG) were used, each with an installed capacity...
-
The Simulation of Activated Sludge System for Optimization of Predictive Aeration at Large WWTP
PublicationEffective use of biodegradable substrates as an internal carbon sources (ICS) for denitrification and EBPR and predicting performance of aeration systems during nitrification in activated sludge bioreactors, may be useful in realization the sustainable development by potentially saving energy consumption at WWTPs. A large number of WWTPs use activated sludge systems with an integrated removal of carbon, nitrogen and phosphorus...
-
Knowledge-Based Virtual Modeling and Simulation of Manufacturing Processes for Industry 4.0
PublicationABSTRACT Industry 4.0 aims at providing a digital representation of a production landscape, but the challenges in building, maintaining, optimizing, and evolving digital models in inter-organizational production chains have not been identified yet in a systematic manner. In this paper, various Industry 4.0 research and technical challenges are addressed, and their present scenario is discussed. Moreover, in this article, the novel...
-
Simulation studies into quayside transport and storage yard operations in container terminals
PublicationThe focus of the paper is on quayside transport and storage yard operations in the sea container terminals. Developed algorithms for solving the issues of load handling and storage space allocation have been applied in the frame of adopted simulation model. The criteria chosen for decision making involved the total makespan of vessel unloading and the utilisation levels of the transportation trucks. Recommendations for unloading...
-
Simulation of shear localization in granular bodies within gradient-enhanced hypoplasticity.
PublicationW artykule przedstawiono wyniki numerycznej analizy ściskania w płaskim stanie odkształcenia dla materiałów granulowanych. Obliczenia przeprowadzono z modelem hipoplastycznym rozszerzonym o gradienty modułu przyrostu odkształceń. Obliczenia wykonano dla różnych długości charakterystycznych w próbce piasku zagęszczonego.
-
Economic and clinical evaluation of vagus nerve stimulation therapy
Publication -
Towards Temperature Dependent Coarse-grained Potential of Side-chain Interactions for Protein Folding Simulations
Publication -
UNRES server for physics-based coarse-grained simulations and prediction of protein structure, dynamics and thermodynamics
Publication -
The Effect of Sterols on Amphotericin B Self-Aggregation in a Lipid Bilayer as Revealed by Free Energy Simulations
PublicationAmphotericin B (AmB) is an effective but toxic antifungal drug, known to increase the permeability of the cell membrane, presumably by assembling into transmembrane pores in a sterol-dependent manner. The aggregation of AmB molecules in a phospholipid bilayer is, thus, crucial for the drug’s activity. To provide an insight into the molecular nature of this process, here, we report an atomistic molecular dynamics simulation study...
-
Communication and Load Balancing Optimization for Finite Element Electromagnetic Simulations Using Multi-GPU Workstation
PublicationThis paper considers a method for accelerating finite-element simulations of electromagnetic problems on a workstation using graphics processing units (GPUs). The focus is on finite-element formulations using higher order elements and tetrahedral meshes that lead to sparse matrices too large to be dealt with on a typical workstation using direct methods. We discuss the problem of rapid matrix generation and assembly, as well as...
-
LS-DYNA simulations of the impacts of a 38-ton Heavy Goods Vehicle into a road cable barrier
PublicationNowadays, more and more attention is being paid to safety on roads and motorways. It is due to the continuous development of road and motorway network and a significant increase of the number of vehicles on roads. To meet the expectations of improving road safety in Poland, the Road Innovations Development (RID) research programme was implemented in 2016. The aim of the RID 3A - Road Safety Equipment (RoSE) project is a comprehensive...
-
Experimental and numerical simulations of flow and heat transfer in heatexchanger elements using liquid crystal thermography.
PublicationPrzedstawienie koncepcji badań eksperymentalnych i numerycznych oraz ich wyników podczas wymiany ciepła w modelach klasycznych i płytowych wymienników ciepła w warunków przepływów przejściowych i turbulentnych.
-
Measurements of glucose content in scattering media with time-of-flight technique: comparison with Monte Carlo simulations.
PublicationZbadano możliwości pomiaru koncentracji glukozy w materiale silnie rozpraszającym światło z wykorzystaniem techniki czasu przelotu. Badania przeprowadzono wykorzystując ''Intralipid'' będącym fantomem tkanki. Stężenie glukozy wynosiło 100, 200, 300, 500, 1000, 2000,4000 lub 8000 mg/dl. Wyniki pomiarów porównano z wynikami uzyskanymi na drodze modelowania matematycznego.
-
Experimental tests and numerical simulations of full scale composite sandwich segment of a foot- and cycle- bridge
PublicationIn the paper experimental tests and numerical simulations of a full cross-section segment of ultimately designed foot-and cycle-bridge are presented. The experimental tests were conducted on element with length reduced to 3 m and unchanged (target) cross-section dimensions. The external skin of structure is GFRP laminate while internal core is PET foam. Several quasi-static tests were performed using hydraulic cylinder to generate...
-
Anion–water interactions of weakly hydrated anions: molecular dynamics simulations of aqueous NaBF4 and NaPF6
PublicationIn aqueous ionic solutions, both the structure and the dynamics of water are altered dramatically with respect to the pure solvent. The emergence of novel experimental techniques makes these changes accessible to detailed investigations. At the same time, computational studies deliver unique possibilities for the interpretation of the experimental data at the molecular level. Here, using molecular dynamics simulations, we demonstrate...
-
Speed estimation of a car at impact with a W-beam guardrail using numerical simulations and machine learning
PublicationThis paper aimed at developing a new method of estimating the impact speed of a passenger car at the moment of a crash into a W-beam road safety barrier. The determination of such a speed based on the accident outcomes is demanding, because often there is no access to full accident data. However, accurate determination of the impact speed is one of the key elements in the reconstruction of road accidents. A machine learning algorithm...
-
Comparison of Absorbed and Intercepted Fractions of PAR for Individual Trees Based on Radiative Transfer Model Simulations
PublicationThe fraction of absorbed photosynthetically active radiation (fAPAR) is a key parameter for estimating the gross primary production (GPP) of trees. For continuous, dense forest canopies, fAPAR, is often equated with the intercepted fraction, fIPAR. This assumption is not valid for individual trees in urban environments or parkland settings where the canopy is sparse and there are well-defined tree crown boundaries. Here, the distinction...
-
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...
-
Surrogate modeling of impedance matching transformers by means of variable‐fidelity electromagnetic simulations and nested cokriging
PublicationAccurate performance evaluation of microwave components can be carried out using full‐wave electromagnetic (EM) simulation tools, routinely employed for circuit verification but also in the design process itself. Unfortunately, the computational cost of EM‐driven design may be high. This is especially pertinent to tasks entailing considerable number of simulations (eg, parametric optimization, statistical analysis). A possible...
-
Structural and dynamic insights on the EmrE protein with TPP+ and related substrates through molecular dynamics simulations
PublicationEmrE is a bacterial transporter protein that forms an anti-parallel homodimer with four transmembrane helices in each monomer. EmrE transports positively charged aromatic compounds, such as TPP+ and its derivatives. We performed molecular dynamics (MD) simulations of EmrE in complex with TPP+, MeTPP+, and MBTPP+ embedded in a membrane. The detailed molecular properties and interactions were analysed for all EmrE-ligand complexes....
-
Simulations of freshwater lens recharge and salt/freshwater interfaces using the HYDRUS and SWI2 packages for MODFLOW
PublicationThe paper presents an evaluation of the combined use of the HYDRUS and SWI2 packages for MODFLOW as a potential tool for modeling recharge in coastal aquife rs subject to saltwater intrusion. The HYDRUS package for MODFLOW solves numerically the one-dimensional form of the Richards equation describing water flow in variably- saturated media. The code computes groundwater recharge to or...
-
Pre‐exascale HPC approaches for molecular dynamics simulations. Covid‐19 research: A use case
PublicationExascale computing has been a dream for ages and is close to becoming a reality that will impact how molecular simulations are being performed, as well as the quantity and quality of the information derived for them. We review how the biomolecular simulations field is anticipating these new architectures, making emphasis on recent work from groups in the BioExcel Center of Excellence for High Performance Computing. We exemplified...
-
Solvent Exchange around Aqueous Zn(II) from Ab Initio Molecular Dynamics Simulations
PublicationHydrated zinc(II) cations, due to their importance in biological systems, are the subject of ongoing research concerning their hydration shell structure and dynamics. Here, ab initio molecular dynamics (AIMD) simulations are used to study solvent exchange events around aqueous Zn2+, for which observation in detail is possible owing to the considerable length of the generated trajectory. While the hexacoordinated Zn(H2O)62+ is the...
-
Rapid Yield Optimization of Miniaturized Microwave Passives by Response Features and Variable-Fidelity EM Simulations
PublicationThe operation of high-frequency devices, including microwave passive components, can be impaired by fabrication tolerances but also incomplete knowledge concerning operating conditions (temperature, input power levels) and material parameters (e.g., substrate permittivity). Although the accuracy of manufacturing processes is always limited, the effects of parameter deviations can be accounted for in advance at the design phase...
-
Long‐time scale simulations of virus‐like particles from three human‐norovirus strains
PublicationThe dynamics of the virus like particles (VLPs) corresponding to the GII.4 Houston, GII.2 SMV, and GI.1 Norwalk strains of human noroviruses (HuNoV) that cause gastroenteritis was investigated by means of long-time (about 30 μs in the laboratory timescale) molecular dynamics simulations with the coarse-grained UNRES force field. The main motion of VLP units turned out to be the bending at the junction between the P1 subdomain (that...
-
Mechanical Properties of Twisted Carbon Nanotube Bundles with Carbon Linkers from Molecular Dynamics Simulations
PublicationThe manufacturing of high-modulus, high-strength fibers is of paramount importance for real-world, high-end applications. In this respect, carbon nanotubes represent the ideal candidates for realizing such fibers. However, their remarkable mechanical performance is difficult to bring up to the macroscale, due to the low load transfer within the fiber. A strategy to increase such load transfer is the introduction of chemical linkers...
-
Brownian Motion in Optical Tweezers, a Comparison between MD Simulations and Experimental Data in the Ballistic Regime
PublicationThe four most popular water models in molecular dynamics were studied in large-scale simulations of Brownian motion of colloidal particles in optical tweezers and then compared with experimental measurements in the same time scale. We present the most direct comparison of colloidal polystyrene particle diffusion in molecular dynamics simulations and experimental data on the same time scales in the ballistic regime. The four most...
-
Homogeneous nucleation rate of methane hydrate formation under experimental conditions from seeding simulations
PublicationIn this work, we shall estimate via computer simulations the homogeneous nucleation rate for the methane hydrate at 400 bars for a supercooling of about 35 K. The TIP4P/ICE model and a Lennard-Jones center were used for water and methane, respectively. To estimate the nucleation rate, the seeding technique was employed. Clusters of the methane hydrate of different sizes were inserted into the aqueous phase of a two-phase gas–liquid...
-
FE-simulations of dynamic shear localization in granular bodies using an Arbitrary Lagrangian-Eulerian formulation.
PublicationW artykule przedstawiono wyniki symulacji lokalizacji odkształceń w materiałach granulowanych. Obliczenia wykonano przy zastosowaniu nielokalnego modelu hipoplastycznego dla 2 różnych problemów: sciskania dwuosiowego i przepływu silosowego. W obliczeniach wykorzystano sformułowanie ALE.
-
Effect of Soft Handover on the Capacity of WCMDA/FDD Interfece Using MRC RAKE Receiver in Uplink
PublicationIn the paper the mechanism of soft and hard hanover in UMTS is presented. Simulation tests for different services having various performance requirements and transmission rates have beeen made. Simulation results showing effect of soft handover in comparison with hard handover on the capacity of WCMDA/FDD radio interfaceare described, when the RAKE receiver with Maximal Ratio Combining has been implemented in RNC.
-
Charakterystyki jakościowe i pojemnościowe interfejsu radiowego WCDMA/FDD w łączu w dół
PublicationW referacie przedstawiono analizę charakterystyk jakościowych i pojemnościowych interfejsu WCDMA/FDD w łączu w dół. Określono wpływ otrogonalności odbieranych sygnałów oraz interferencji zewnętrznych na jakość i pojemność w różnych środowiskach propagacyjnych.
-
Kształtowanie pojemności interfejsu radiowego WCDMA/FDD w sieci UMTS o strukturze hierarchicznej
PublicationW artykule przedstawiono wyniki badań symulacyjnych mechanizmu przenoszenia pojemności pomiędzy komórkami w różnych warstwach hierarchicznej struktury komórek w sieci UMTS. Opisywana metoda zarządzania obciążeniem może być przydatna do zwiększenia efektywności wykorzystania zasobów radiowych. Sieć komórkowa została zaimplementowana na cyfrowej mapie Gdańska.
-
Wpływ makrodywersyfikacji na pojemność interfejsu radiowego WCDMA/FDD w łączu w górę
PublicationW referacie przedstawiono analizę wpływu makrodywersyfikacji na pojemność interfejsu radiowego WCDMA/FDD systemu UMTS w łączu w górę. Ponadto przedstawiono wyniki badań symulacyjnych potwierdzających słuszność przeprowadzonej analizy matematycznej.
-
Downlink Capacity-Coverage Trade-off Estimation Based on Measurement of WCDMA/FDD Interface Load
PublicationThe method of capacity-coverage trade-off determination by using of universal load characteristics and normalized coverage curves for the WCDMA/FDD radio interface has been presented. The practical applications of discussed method for UMTS radio network planning process and network exploitation has been mentioned.
-
Kształtowanie pojemności interfejsu radiowego WCDMA/FDD w sieci UMTS o strukturze hierarchicznej
PublicationW referacie przedstawiono wyniki badań symulacyjnych mechanizmu przenoszenia pojemności pomiędzy komórkami w różnych warstwach hierarchicznej struktury komórek w sieci UMTS. Sieć komórkowa została zaplanowana na cyfrowej mapie miasta Gdańska
-
Wspólnokanałowe interferencje zewnętrzne w interfejsie radiowym WCDMA/FDD w łączu w dół
PublicationW artykule przedstawiono analizę interferencji własnych i zewnętrznych w interfejsie radiowym WCDMA/FDD w łączu w dół.
-
Własności korelacyjne zespolonych ciągów Golda w interfejsie radiowym WCDMA/FDD systemu UMTS
PublicationW referacie przedstawiono dyskusję na temat własności korelacyjnych zespolonych ciągów rozpraszających stosowanych w interfejsie WCDMA/FDD systemu UMTS.