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Search results for: ELECTROMAGNETIC (EM) MODELING
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Ionosphere variability II: Advances in theory and modeling
PublicationThis paper aims to provide an overview on recent advances in ionospheric modeling capabilities, with the emphasis in the efforts relevant to electron density variability. The discussion spans a wide range of model formulations (e.g., from purely empirical to physics-based ones and data-driven approaches) seeking for advances or gaps with regard to present challenges. This discussion is further supported by consideration of the...
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Visual Dimensions of Modeling Languages in Interdisciplinary Perspective
PublicationUżyteczność języków modelowania wizualnego zależy od notacji. Notacja może być postrzegana jako zestaw wizualnych komponentów, które w określony sposób oddziałują na ludzkie oko i ludzki mózg. Referat przedstawia analizę interdyscyplinarną wykonaną w celu lepszego zrozumienia wizualnych wymiarów języków modelowania. Wizualne wymiary pochodzą z teorii opisujących percepcję wzrokową, wizualizację danych oraz reprezentacje poznawcze....
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Multimodal Particle Swarm Optimization with Phase Analysis to Solve Complex Equations of Electromagnetic Analysis
PublicationIn this paper, a new meta-heuristic method of finding roots and poles of a complex function of a complex variable is presented. The algorithm combines an efficient space exploration provided by the particle swarm optimization (PSO) and the classification of root and pole occurrences based on the phase analysis of the complex function. The method initially generates two uniformly distributed populations of particles on the complex...
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ENTERPRISE ACTIVITIES MODELING BY BPMN NOTATION
PublicationDepending on the process behavior, available know-how and organizational goals, different techniques and tools can be used for business process modeling. We concentrate on e-commerce, and try to find the best marketing strategy for the sales process improvement. In the paper we present the multilayer approach to define enterprise scenarios. This allows us to collect the suitable knowledge necessary for enterprise analysis and improvement....
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Modeling emotions for affect-aware applications
PublicationThe chapter concerns emotional states representation and modeling for software systems, that deal with human affect. A review of emotion representation models is provided, including discrete, dimensional and componential models. The paper provides also analysis of emotion models used in diverse types of affect-aware applications: games, mood trackers or tutoring systems. The analysis is supported with two design cases. The study...
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Modeling Parallel Applications in the MERPSYS Environment
PublicationThe chapter presents how to model parallel computational applications for which simulation of execution in a large-scale parallel or distributed environment is performed within the MERPSYS environment. Specifically, it is shown what approaches can be adopted to model key paradigms often used for parallel applications: master-slave, geometric parallelism (single program multiple data), pipelined and divide-and-conquer applications....
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GPU-Accelerated Finite-Element Matrix Generation for Lossless, Lossy, and Tensor Media [EM Programmer's Notebook]
PublicationThis paper presents an optimization approach for limiting memory requirements and enhancing the performance of GPU-accelerated finite-element matrix generation applied in the implementation of the higher-order finite-element method (FEM). It emphasizes the details of the implementation of the matrix-generation algorithm for the simulation of electromagnetic wave propagation in lossless, lossy, and tensor media. Moreover, the impact...
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Electromagnetic Field Associated With Dermoscope Magnets May Affect the Safety of Cardiac Implanted Electronic Devices Patients
PublicationDermoscopy is currently used as an auxiliary tool in general dermatology. Since some commercially available dermoscopes have built-in magnets, electromagnetic interference (EMI) may occur when examining cardiac implantable electronic devices (CIED) patients. The aim of the study was to create maps of electromagnetic fields defining a safe distance in terms of EMI. The study was performed in laboratory conditions using measuring...
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Design-Oriented Constrained Modeling of Antenna Structures
PublicationFast surrogate models are crucially important to reduce the cost of design process of antenna structures. Due to curse of dimensionality, standard (data-driven) modeling methods exhibit serious limitations concerning the number of independent geometry parameters that can be handled but also (and even more importantly) their parameter ranges. In this work, a design-oriented modeling framework is proposed in which the surrogate is...
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A Concept of Modeling and Optimization of Applications in Large Scale Systems
PublicationThe chapter presents the idea that includes modeling and subsequent optimization of application execution on large scale parallel and distributed systems. The model considers performance, reliability and power consumption. It should allow easy modeling of various classes of applications while reflecting key parameters of both the applications and two classes of target systems: clusters and volunteer based systems. The chapter presents...
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Modeling the application of steel slag in stabilizing expansive soil
PublicationThe objective of this study was to evaluate the suitability of steel slag as an additive to the engineering properties of weak clay soil. Different geotechnical laboratory tests were conducted on both stabilized and natural soils. Steel slag (SS) was added at a rate of 0, 5, 10, 15, 20, and 25% to the soil. Specific gravity, grain size analysis, Atterberg limit test, compaction test, free swell, California bearing ratio (CBR),...
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Modeling SPMD Application Execution Time
PublicationParallel applications in a Single Process Multiple Data paradigm assume splitting huge amounts of data to multiple processors working in parallel at small data packets. As the individual data packets are not independent, the processors must interact with each other to exchange results of the calculations with their adjacent partners and take these results into account in their own computations. An example of SPMD is geometric parallelism...
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Pareto Ranking Bisection Algorithm for EM-Driven Multi-Objective Design of Antennas in Highly-Dimensional Parameter Spaces
PublicationA deterministic technique for fast surrogate-assisted multi-objective design optimization of antennas in highly-dimensional parameters spaces has been discussed. In this two-stage approach, the initial approximation of the Pareto set representing the best compromise between conflicting objectives is obtained using a bisection algorithm which finds new Pareto-optimal designs by dividing the line segments interconnecting previously...
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Dynamic Bayesian Networks for Symbolic Polyphonic Pitch Modeling
PublicationSymbolic pitch modeling is a way of incorporating knowledge about relations between pitches into the process of an- alyzing musical information or signals. In this paper, we propose a family of probabilistic symbolic polyphonic pitch models, which account for both the “horizontal” and the “vertical” pitch struc- ture. These models are formulated as linear or log-linear interpo- lations of up to fi ve sub-models, each of which is...
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Toolchain Modeling: Comprehensive Engineering Plans for Industry 4.0
PublicationThe fourth industrial revolution (Industry 4.0) elevates the complexity and autonomy of industrial systems and engineering environments to levels not seen before. The novel challenges involve not only the software running on the partaking autonomous devices, but also architectural considerations and the technological infrastructure around the entire engineering process. In this paper, complementing the trends in industrial systems...
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Local response surface approximations and variable-fidelity electromagnetic simulations for computationally efficient microwave design optimisation
PublicationIn this study, the authors propose a robust and computationally efficient algorithm for simulation-driven design optimisation of microwave structures. Our technique exploits variable-fidelity electromagnetic models of the structure under consideration. The low-fidelity model is optimised using its local response surface approximation surrogates. The high-fidelity model is refined by space mapping with polynomial interpolation of...
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Electromagnetic compatibility tests of warship antitorpedo jamming system
PublicationW artykule przedstawiono zagadnienie interferencji elektromagnetycznych na okręcie wojennym spowodowanych pracą antytorpedowego systemu zakłócającego. W warunkach laboratoryjnych, dla wybranej konfiguracji systemu, zostały przeprowadzone badania kompatybilnościowe i na podstawie otrzymanych rezultatów zostały sformułowane wnioski praktyczne.
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Naval electromagnetic compatibility investigations by use of topological model
PublicationPublikacja przedstawia zagadnienie uwarunkowań kompatybilnościowych na statkach. Ze względu na trudności jakie stwarza analiza EMC dużych obiektów, środowisko elektromagnetyczne okrętów jest zwykle dzielone na fragmenty analizowane oddzielnie. Referat przedstawia topologiczny model środowiska elektromagnetycznego w formie macierzowej, który pozwala na kompleksową analizę zagadnień kompatybilnościowych wielu systemów pracujących...
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Electromagnetic Interference Issue in Safety Systems Applied at Airports
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Electromagnetic-based derivation of fractional-order circuit theory
PublicationIn this paper, foundations of the fractional-order circuit theory are revisited. Although many papers have been devoted to fractional-order modelling of electrical circuits, there are relatively few foundations for such an approach. Therefore, we derive fractional-order lumped-element equations for capacitors, inductors and resistors, as well as Kirchhoff’s voltage and current laws using quasi-static approximations of fractional-order...
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Modeling energy consumption of parallel applications
PublicationThe 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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Rapid Yield Estimation and Optimization of Microwave Structures Exploiting Feature-Based Statistical Analysis
PublicationIn this paper, we propose a simple, yet reliable methodology to expediteyield estimation and optimization of microwave structures. In our approach,the analysis of the entire response of the structure at hand (e.g., $S$-parameters asa function of frequency) is replaced by response surface modeling of suitablyselected feature points. On the one hand, this is sufficient to determinewhether a design satisfies given performance specifications....
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Modeling pragmatics for visual modeling language evaluation
PublicationPodczas oceny użyteczności języków modelowania wizualnego istnieje potrzeba uwzględnienia ich pragmatyki. Języki modelowania wizualnego mogą być stosowane w różnym kontekście, co powoduje różnice w wymaganiach, które są im stawiane. Jawny opis kontekstu użycia ułatwia precyzyjną ocenę. Pragmatyka składa się ze zbioru profili, które opisują konkretne konteksty użycia. W referacie podjęto próbę zastosowania modeli zadań do opisu...
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Modeling the debonding process of osseointegrated implants due to coupled adhesion and friction
PublicationCementless implants have become widely used for total hip replacement surgery. The long-term stability of these implants is achieved by bone growing around and into the rough surface of the implant, a process called osseointegration. However, debonding of the bone–implant interface can still occur due to aseptic implant loosening and insufficient osseointegration, which may have dramatic consequences. The aim of this work is to...
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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...
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Energy Consumption Modeling in SPMD and DAC Applications
PublicationIn this chapter, we show a study of energy consumption during execution of SPMD and DAC application – the same applications which time of execution we modeled in the previous two chapters. We measured an average power usage at a single node of the GALERA+ cluster during application execution and then we modeled the total energy consumption by the application. Next we simulated the applications using MERPSYS and we compared the...
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Propagation Path Loss Modeling in Container Terminal Environment
PublicationThis paper describes novel method of path loss modeling for radio communication channels in container port area. Multi-variate empirical model is presented, based on multidimensional regression analysis of real path loss measurements from container terminal environment. The measurement instruments used in propagation studies in port area are also described.
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Global Surrogate Modeling by Neural Network-Based Model Uncertainty
PublicationThis work proposes a novel adaptive global surrogate modeling algorithm which uses two neural networks, one for prediction and the other for the model uncertainty. Specifically, the algorithm proceeds in cycles and adaptively enhances the neural network-based surrogate model by selecting the next sampling points guided by an auxiliary neural network approximation of the spatial error. The proposed algorithm is tested numerically...
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Semantic modeling of contextual augmented reality environments
PublicationDespite significant progress in the field of augmented reality (AR), regarding both hardware and software, there is still a lack of universal models and methods that would enable building ubiquitous AR systems that could be used anywhere and anytime, covering different application areas. This dissertation describes a new approach to building AR systems, called the Contextual Augmented Reality Environment (CARE). The CARE approach...
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Analysis of circular polarization antenna design trade‐offs using low‐cost EM‐driven multiobjective optimization
PublicationCircular polarization (CP) antennas are vital components of modern communication systems. Their design involves handling several requirements such as low reflection and axial ratio (AR) within the frequency range of interest. Small size is an important criterion for antenna mobility which is normally achieved as a by‐product of performance‐oriented modifications of the structure topology. In this work, multiobjective optimization...
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Modeling of multi-cavity Fabry-Perot optical fiber sensors
PublicationReflectance characteristics of a two-cavity extrinsic Fabry-Perot optical fiber sensor were investigated using computer modeling. Calculations were performed using a plane wave-based approach, selected for clarity of results. Based on the modeling results, it can be concluded that the two-cavity Fabry-Perot interferometer can be used to measure two different quantities, such as refractive index and temperature, independently. It...
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Improving performance of large thrust bearings through modeling and experimentation
PublicationLarge thrust bearings are highly loaded machine elements and their failures cause serious losses. Start ups and stoppages of the bearing under load are specially critical regimes of operation. Load carrying capacity depends on the profile of the oil gap. In transient states this profile is also changing. In the design of large thrust bearings minimizing thermo-elastic deformations is an important goal, which can be accomplished...
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Modeling and simulation of tool cycle in manufacturing cell
PublicationThe paper addresses issues concerning modeling and analysis of tool flow within a three-machine manufacturing cell used for small batch manufacturing of a definite spectrum of prismatic parts. The approach utilizes a method for job and tool allocation to work centers with limited number of machines and capacity of tool resources, based on the analysis of formalized relations: job - tool sets required. Selected tool flow control...
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Traffic Modeling in IMS-based NGN Networks
PublicationIn the modern world the need for accurate and quickly delivered information is becoming more and more essential. In order to fulfill these requirements, next generation telecommunication networks should be fast introduced and correctly dimensioned. For this reason proper traffic models must be identified, which is the subject of this paper. In the paper standardization of IMS (IP Multimedia Subsystem) concept and IMS-based NGN...
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Surrogate-assisted EM-driven miniaturization of wideband microwave couplers by means of co-simulation low-fidelity models
PublicationThis article proposes a methodology for rapid design optimization of miniaturized wideband couplers. More specifically, a class of circuits is considered, in which conventional transmission lines are replaced by their abbreviated counterparts referred to as slow-wave compact cells. Our focus is on explicit reduction of the structure size as well as on reducing the CPU cost of the design process. For the sake of computational feasibility,...
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Hybrid Technique for the EM Scattering Analysis with the Use of Ring Domain Decomposition
PublicationA hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open space is presented here. The main idea is based on impedance matrix descriptions of the boundary surrounding the discrete computational domain and combine it with external field described analytically. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity...
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Synchronizacja pomiarów z drezyny EM-120 w planowaniu napraw
PublicationW artykule zaprezentowano metodykę synchronizacji pomierzonych nierówności geometrycznych w różnych przedziałach czasowych. Tak opracowane pomiary umożliwiły dokonanie analizy trendu deformacji toru na kilku liniach kolejowych.
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A Stabilized Complex LOBPCG Eigensolver for the Analysis of Moderately Lossy EM Structures
PublicationThis letter proposes a stabilized locally optimal block preconditioned conjugate gradient method for computing selected eigenvalues for complex symmetric generalized non-Hermitian eigenproblems. Effectiveness of the presented approach is demonstrated for a moderately lossy dual-mode dielectric resonator, modeled using finite-element method with higher order elements
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Special Issue "Applications of Finite Element Modeling for Mechanical and Mechatronic Systems"
PublicationNumerical modeling is very important in today's engineering because, among other things, it reduces the costs associated with prototyping or predicting the occurrence of potentially dangerous situations during operation in certain defined conditions. Different methods have so far been used to implement the real structure into the numerical version. The most popular have been variations of the finite element method (FEM). The aim...
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Characterization of Defects Inside the Cable Dielectric With Partial Discharge Modeling
PublicationThe continuous monitoring of power system devices is an important step toward keeping such capital assets safe. Partial discharge (PD)-based measurement tools provide a reliable and accurate condition assessment of power system insulations. It is very common that voids or cavities exist in every solid dielectric insulation medium. In this article, different voids are modeled and analyzed using an advanced finite element (FE)-based...
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One-Dimensional Modeling of Flows in Open Channels
PublicationIn this chapter, modeling of the unsteady open channel flow using one-dimensional approach is considered. As this question belongs to the well-known and standard problems of open channel hydraulic engineering, comprehensively presented and described in many books and publications, our attention is focused on some selected aspects only. As far as the numerical solution of the governing equations is considered, one can find out that...
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Performance and Power-Aware Modeling of MPI Applications for Cluster Computing
PublicationThe paper presents modeling of performance and power consumption when running parallel applications on modern cluster-based systems. The model includes basic so-called blocks representing either computations or communication. The latter includes both point-to-point and collective communication. Real measurements were performed using MPI applications and routines run on three different clusters with both Infiniband and Gigabit Ethernet...
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A coarse‐grained approach to NMR ‐data‐assisted modeling of protein structures
PublicationThe ESCASA algorithm for analytical estimation of proton positions from coarse-grained geometry developed in our recent work has been implemented in modeling protein structures with the highly coarse-grained UNRES model of polypeptide chains (two sites per residue) and nuclear magnetic resonance (NMR) data. A penalty function with the shape of intersecting gorges was applied to treat ambiguous distance restraints, which automatically...
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Thermodynamic and electromagnetic properties of hard-core charged bosons on a lattice
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Nonlinear evolution of components of electromagnetic field of helicoidal wave in plasma
PublicationWyprowadzilismy model równań opisujących oddziaływanie pomiedzy kołowo spolaryzowanymi paczkami fal helikoidalnych w dwuwymiarowej plazmie. Dla quasi-jednowymiarowego przypadku otrzymaliśmy warunek nieliniowego rezonansu dla oddziaływania N-fal. Nowym ''osiągnięciem'' badań w kontekscie teorii solitonów, jest znalezienie rozwiązań dla przypadku asynchronizmu fal, które wydaje się być podstawowym dla paczek falowych nachylonych...
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Electromagnetic Field Measurements of Bow Thruster Drive with Frequency Converter
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Domain Reduction in Hybrid Technique for Electromagnetic Wave Scattering Problems
PublicationThis paper proposes a combination of the field matching technique, finite element method and generalized impedance matrix, the main idea of which is to reduce the computational domain by surrounding a scatterer with the smallest convex shape and applying the field matching technique. This approach can be applied for arbitrary shaped scatterers and types of materials and allows for the reduction of the computational domain. In order...
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Electromagnetic properties of a dielectric slab with an embedded silver nanowire grating
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Electromagnetic characterization of a silver nanowire grating embedded into a dielectric slab
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Electromagnetic curtain effect and tunneling properties of multilayered periodic structures
PublicationArtykuł przedstawia analizę rozpraszania fali elektromagnetycznej na wielowarstwowych strukturach periodycznych. W analizowanych strukturach zaobserwowano efekt tunelowania fali oraz efekt przestrajania pasm zaporowych/przepustowych (efekt kurtyny elektromagnetycznej)