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Search results for: FRACTIONAL-ORDER SYSTEMS
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Rule-Based Model for Selecting Integration Technologies for Smart Cities Systems
PublicationThe aim of this article is to present the stages of development for an information technology integration model for the design of systems for smart cities. The Introduction explains the need for integration technologies and presents a model for selecting integration technologies and the conditions for its use in designing smart cities systems. Then two verification stages of the presented model are discussed. In the first stage,...
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Wideband Model Order Reduction for Macromodels in Finite Element Method
PublicationAbstract: This paper presents a novel algorithm for accelerating 3D Finite Element Method simulations by introducing macromodels created in local model order reduction in the selected subdomains of the computational domain. It generates the projection basis for a compact system of equations associated with a separate subdomain. Due to non-linear frequency dependency in the Right Hand Side (RHS), the standard reduction methods do...
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On weak solutions of boundary value problems within the surface elasticity of Nth order
PublicationA study of existence and uniqueness of weak solutions to boundary value problems describing an elastic body with weakly nonlocal surface elasticity is presented. The chosen model incorporates the surface strain energy as a quadratic function of the surface strain tensor and the surface deformation gradients up to Nth order. The virtual work principle, extended for higher‐order strain gradient media, serves as a basis for defining...
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Novel Nonlinear High Order Technologies for Damage Diagnosis of Complex Assets
PublicationFor the first time worldwide, innovative techniques, generic non-linear higher-order unnormalized cross-correlations of spectral moduli, for the diagnosis of complex assets, are proposed. The normalization of the proposed techniques is based on the absolute central moments, that have been proposed and widely investigated in mathematical works. The existing higher-order, crosscovariances of complex spectral components are not sufficiently...
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Real-time Operating Systems - Seminar 2023/4
e-Learning CoursesPage to support seminar clases of Real-time Operating Systems
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Identification of nonstationary multivariate autoregressive processes– Comparison of competitive and collaborative strategies for joint selection of estimation bandwidth and model order
PublicationThe problem of identification of multivariate autoregressive processes (systems or signals) with unknown and possibly time-varying model order and time-varying rate of parameter variation is considered and solved using parallel estimation approach. Under this approach, several local estimation algorithms, with different order and bandwidth settings, are run simultaneously and compared based on their predictive performance. First,...
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Database management systems - lecture 2024/2025
e-Learning CoursesKurs dedykowany do wykładów prowadzonych wspólnie dla przedmiotu Zarządzanie Systemami Baz Danych na kierunku Informatyka oraz Database management systems na kierunku inżynieria danych.
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Geometry Parametric Model Order Reduction with Randomly Generated Projection Bases
PublicationIn this work, a reduced-order model for geometry parameters and fast frequency sweep is proposed. The Finite Element Method is used to solve time-harmonic Maxwell’s equations. Taking into account the electromagnetic field does not arbitrarily vary as a function of frequency and geometry parameters, a low dimension system manifold is identified. Thus, the original Finite Element problem can be approximated by a model of reduced...
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Potential Application of Solar Energy Systems for Electrified Urban Transportation Systems
PublicationThe paper presents a novel approach toward the use of solar energy systems in public transportation. The concept of energy generation in PV systems for supplying a trolleybus transportation system is proposed for the city of Gdynia (Poland). The suggested way of energy production allows reducing the environmental harm impact of the municipal transportation system. Moreover, the proposed way of green energy use can be a more profitable...
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Periodic Solutions of Generalized Lagrangian Systems with Small Perturbations
PublicationIn this paper we study the generalized Lagrangian system with a small perturbation. We assume the main term in the system to have a maximum, but do not suppose any condition for perturbation term. Then we prove the existence of a periodic solution via Ekeland’s principle. Moreover, we prove a convergence theorem for periodic solutions of perturbed systems.
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Fractional Calculus Evaluation of Hyaluronic Acid Crosslinking in a Nanoscopic Part of Articular Cartilage Model System
PublicationThis work presents a study of the mechanism of physical crosslinking of hyaluronic acid in the presence of common phospholipids in synovial joint organ systems. Molecular dynamic simulations have been executed to understand the formation of hyaluronan networks at various phospholipid concentrations. The results of the simulations suggest that the mechanisms exhibit subdiffusion characteristics. Transportation quantities derive...
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A CONTEXT IN RECOMMENDER SYSTEMS
PublicationRecommender systems aim to propose potentially interesting items to a user based on his preferences or previous interaction with the system. In the last decade, researcher found out that known recommendation techniques are not sufficient to predict user decisions. It has been noticed that user preferences strongly depend on the context in which he currently is. This raises new challenges for the researchers such as how to obtain...
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From Knowledge based Vision Systems to Cognitive Vision Systems: A Review
PublicationComputer vision research and applications have their origins in 1960s. Limitations in computational resources inherent of that time, among other reasons, caused research to move away from artificial intelligence and generic recognition goals to accomplish simple tasks for constrained scenarios. In the past decades, the development in machine learning techniques has contributed to noteworthy progress in vision systems. However,...
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Communication Model Order Reduction in Hybrid Methods Involving Generalized Impedance Matrix
PublicationA novel strategy for the efficient analysis of frequency-domain scattering electromagnetic problems in open and closed domains is presented. A fully automatic model-order reduction technique, called the enhanced reduced-basis method, is applied to increase the efficiency of the hybrid approach, which combines the finite-element and mode-matching methods. Numerical tests show that the proposed algorithm yields reliable and highly...
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Hybrid, Approximate Models of Distributed-Parameter Systems
PublicationThe paper introduces the method of distributed-parameter systems modelling. It enables to obtain low order modal model of the system that experiences Coriolis acceleration component and gyroscopic effect. In such cases, corresponding system equations are non-self-adjoined. To solve this problem modal reduced model is built up for the system without Coriolis acceleration or gyroscopic effect terms. These phenomena are next included...
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Context-Aware Indexing and Retrieval for Cognitive Systems Using SOEKS and DDNA
PublicationVisual content searching, browsing and retrieval tools have been a focus area of interest as they are required by systems from many different domains. Context-based, Content-Based, and Semantic-based are different approaches utilized for indexing/retrieving, but have their drawbacks when applied to systems that aim to mimic the human capabilities. Such systems, also known as Cognitive Systems, are still limited in terms of processing...
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Perspectives of Transport Systems Development in the Light of Radio Communication Systems Evolution Towards 5G
PublicationIn the paper conditions of development and implementation of transport systems with reference to the development of radio communication networks towards 5G are presented. First, general properties of next generation systems are mentioned and their architecture. Moreover, planned characteristics of B4G and 5G systems are depicted which can significantly contribute to the promotion and development of transport systems. In particular...
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Simulation model for evaluation of packet sequence changed order of stream in DiffServ network
PublicationCurrent packet networks use a large variety of mechanisms which should support QoS (Quality of Service). One of those mechanisms is routing (calculating connection paths for incoming service requests). The most effective mechanism in QoS context is dynamic routing, which is based on the current network state described by the offered traffic matrix and link states. After switching between calculated available paths, connection...
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Losses and energy efficiency of drive motors and systems
PublicationLosses and energy efficiency of every drive motor must be presented as functions of physical quantities independent of losses in the motor. Such quantities are speed and load required by the machine or device driven by the motor, changing in the drive operating field. Speed and load of the motor decide of the instantaneous useful power of the motor and also in a differentiated way of kinds and values of losses occurring in the...
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Losses and energy efficiency of drive motors and systems
PublicationLosses and energy efficiency of every drive motor must be presented as functions of physical quantities independent of losses in the motor. Such quantities are speed and load required by the machine or device driven by the motor, changing in the drive operating field. Speed and load of the motor decide of the instantaneous useful power of the motor and also in a differentiated way of kinds and values of losses occurring in the...
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Editorial: Applied intelligence and knowledge based systems: approaches and case studies - part 2
PublicationWydanie Cybernetics and Systems poswiecone zagadnieniom zarzadzania wiedza.
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Cognitive memory for intelligent systems of decision-making, based on human psychology
PublicationA model of memory, which allows to expand the functionality of autonomous decision-making systems for robotic and human-system-interface purposes, is discussed. The model provides functions and features which make the prospective robotic and interfacing systems more human-like as well as more efficient in solving interactive issues.
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Optimization issues in distributed computing systems design
PublicationIn recent years, we observe a growing interest focused on distributed computing systems. Both industry and academia require increasing computational power to process and analyze large amount of data, including significant areas like analysis of medical data, earthquake, or weather forecast. Since distributed computing systems – similar to computer networks – are vulnerable to failures, survivability mechanisms are indispensable...
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FEW-BODY SYSTEMS
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Spurious Modes in Model Order Reduction in Variational Problems in Electromagnetics
PublicationIn this work, we address an everlasting issue in 2 model order reduction (MOR) in electromagnetics that has 3 remained unnoticed until now. Contrary to what has been 4 previously done, we identify for the very first time spurious 5 modes in MOR for time-harmonic Maxwell’s equations and 6 propose a methodology to remove their negative influence on the 7 reduced order model (ROM) response. These spurious modes 8 have nonzero resonance...
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Stripe order and magnetic anisotropy in the S=1 antiferromagnet BaMoP2O8
PublicationMagnetic behavior of yavapaiite-type BaMoP2O8 with the spatially anisotropic triangular arrangement of the S=1Mo4+ ions is explored using thermodynamic measurements, neutron diffraction, and density-functional band-structure calculations. A broad maximum in the magnetic susceptibility around 46 K is followed by the stripe antiferromagnetic order with the propagation vector k=(12,12,12) formed below TN≃21 K. This stripe phase is...
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Compressed Projection Bases for Model-Order Reduction of Multiport Microwave Components Using FEM
PublicationThis paper presents a projection basis compression technique for generating compact reduced-order models (ROM) in the FE analysis of microwave devices. In this approach redundancy is removed from the projection basis by means of the proper orthogonal decomposition technique applied to the projected system of linear equations. Compression allows for keeping the size of a reduced-order model as small as possible without compromising...
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Stability by linear approximation for time scale dynamical systems
PublicationWe study systems on time scales that are generalizations of classical differential or difference equations and appear in numerical methods. In this paper we consider linear systems and their small nonlinear perturbations. In terms of time scales and of eigenvalues of matrices we formulate conditions, sufficient for stability by linear approximation. For non-periodic time scales we use techniques of central upper Lyapunov exponents...
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Survey of Radio Navigation Systems
PublicationAt present, there is a growing demand for radio navigation systems, ranging from pedestrian navigation to consumer behavior analysis. These systems have been successfully used in many applications and have become very popular in recent years. In this paper we present a review of selected wireless positioning solutions operating in both indoor and outdoor environments. We describe different positioning techniques, methods, systems,...
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Methodology of Selecting the Hadoop Ecosystem Configuration in Order to Improve the Performance of a Plagiarism Detection System
PublicationThe plagiarism detection problem involves finding patterns in unstructured text documents. Similarity of documents in this approach means that the documents contain some identical phrases with defined minimal length. The typical methods used to find similar documents in dig- ital libraries are not suitable for this task (plagiarism detection) because found documents may contain similar content and we have not any war- ranty that...
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Multi-state multi-reference Møller-Plesset second-order perturbation theory for molecular calculations
PublicationThis work presents multi‐state multi‐reference Møller–Plesset second‐order perturbation theory as a variant of multi‐reference perturbation theory to treat electron correlation in molecules. An effective Hamiltonian is constructed from the first‐order wave operator to treat several strongly interacting electronic states simultaneously. The wave operator is obtained by solving the generalized Bloch equation within the first‐order...
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Introduction to the special issue on intelligent systems to aid the handicapped.
PublicationWśród wielu zastosowań sztucznej inteligencji i technologii bazodanowych pojawiają się zastosowania wspierające osoby niepełnosprawne. Z chwilą pojawienia są każdej nowej technologii komputerowej świat naukowy proponuje zastosowania tej technologii do celu poprawy komunikacji z osobami niepełnosprawnymi bądź technologie wspierające te osoby bezpośrednio. Niniejsze wydanie specjalne czasopisma Journal of Intelligent Information...
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Geometric methods in dynamical systems modelling: electrical, mechanical and control systems
PublicationRozważono zagadnienia modelowania systemów dynamicznych z zastosowaniem metod geometrii różniczkowej. Równania dynamiczne otrzymano w postaci inkluzji różniczkowych. Przestrzenie konstytucyjne przyjęto w postaci subwiązek włóknistych. Rozważono przestrzenie konstytucyjne układów elektrycznych, układów mechanicznych i układów sterowania. Podstawowe wyniki pracy dotyczą struktury przestrzeni rozwiązań rozważanych systemów.
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ORDER-A JOURNAL ON THE THEORY OF ORDERED SETS AND ITS APPLICATIONS
Journals -
Jacek Stefański prof. dr hab. inż.
PeopleJJacek Stefański received M.Sc., Ph.D. and D.Sc. degrees in telecommunications engineering from Gdansk University of Technology (GUT), Poland, in 1993, 2000 and 2012, respectively. Awarded title of Professor by the President of Poland in 2020. Currently, he works as a professor at the Department of Radio Communication Systems and Networks (DRCSN) in GUT. From 2005 to 2009, he worked as an assistant professor in the National Institute...
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Dynamic Execution of Engineering Processes in Cyber-Physical Systems of Systems Toolchains
PublicationEngineering tools support the process of creating, operating, maintaining, and evolving systems throughout their lifecycle. Toolchains are sequences of tools that build on each others' output during this procedure. The complete chain of tools itself may not even be recognized by the humans who utilize them, people may just recognize the right tool being used at the right place in time. Modern engineering processes, however, do...
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Security and Anonymity in Agent Systems
PublicationMany agent systems have been developed and suggested for commercial application. However, in spite of the significant potential offered by the agent paradigm, the lack of such important properties as security, anonymity and untracebility especially in open dynamical environment, such as the Internet, has blocked the active implementation of agent technologies. Protecting agent systems poses a more demanding challenge comparing...
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Global Development and International Order Transition
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First-order advanced difference equations
PublicationBadano istnienie rozwiązań równań różnicowych rzędu pierwszego z wyprzedzonymi argumentami. Podano warunki na istnienie jedynego rozwiązania. Przedmiotem badań były też nierówności różnicowe związane z w/w równaniami różnicowymi. Otrzymane wyniki zilustrowano na przykładzie.
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Functional differential equations of second order.
PublicationPraca dotyczy problemu brzegowego dla równań różniczkowo-funkcyjnych 2-go rzędu. Stosując metodę kwasilinearyzacji pokazano, że odpowiednio skonstruowane ciągi monotoniczne są zbieżne do jedynego rozwiązania danego problemu i ustalono szybkość tej zbieżności. Pokazano również pewną relację pomiędzy rozwiązaniami odpowiednich liniowych równań różniczkowo-funkcyjnych z warunkami brzegowymi.
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High order of nongeminate recombination in organic bulk heterojunction solar cells
PublicationWe analyze high order of nongeminate recombination in organic donor–acceptor bulk heterojunction solar cells. The model of recombination where an exciton annihilates on an electron–hole Langevin bound pair near donor–acceptor interface has been applied in our studies. We obtained satisfactory agreement between experimental results and theoretical calculations for the concentration dependences of several parameters characterizing...
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Gain deficit effect in the fractional delay filter design by the window method
PublicationMetoda okien jest sposobem szybkiego i skutecznego projektowania filtrów ułamkowoopóźniających. Jednakże wzmocnienie tak zaprojektowanego filtru różni się od zakładanej wartości idealnej. To zjawisko, nazywane deficytem wzmocnienia, negatywnie wpływa na jakoś projektowanego filtru. Artykuł poświęcono wynikom badań oraz metodom korekcji tego problemu. Omówiono wpływ współczynnika korekcji deficytu wzmocnienia na charakterystykę...
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Fractional delayor application in self-tuning sub-sample delay estimator
PublicationW artykule przedstawiono nowe rozwiązanie samonastrajalnego estymatora opóźnienia sygnału sinusoidalnego. Estymator działa w czasie dyskretnym. Proponowane rozwiązanie wykorzystuje kaskadowe połączenie cyfrowego filtru ułamkowo opóźniającego służącego do synchronizacji próbkowania i liniowo-fazowego cyfrowego filtru Hilberta. Oryginalność polega na zastosowaniu tu filtrów cyfrowych o bardzo małej złożoności numerycznej. Jest ona...
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Extracted window offsetting using maximally flat fractional delay filter
PublicationW pracy przedstawiono koncepcję projektowania filtru ułamkowoopóźniającego (FD) z wykorzystaniem metody okien offsetowanych. W zaproponowanym podejściu jako okna prototypowego, offsetowanego o opóźnienie ułamkowe projektowanego filtru, użyto okna wyodrębnionego z odpowiedzi impulsowej filtru optymalnego. Zaprojektowane w ten sposób filtry FD nie są optymalne jednak zapewniają lepszą jakość algorytmu zmiany szybkości próbkowania...
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Existence results to delay fractional differential equations with nonlinear boundary conditions
PublicationPraca dotyczy problemów brzegowych dla ułamkowych równań różniczkowych z opóźnionym argumentem. Podano warunki dostateczne na istnienie rozwiązań ekstremalnych takich zagadnień.
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Farrow structure implementation of fractional delay filter optimal in Chebyshev sense
PublicationW pracy omówiono problematykę implementacji filtrów ułamkowych opóźniających o zmiennym opóźnieniu w oparciu o strukturę Farrowa. Podejście to polega na obliczeniu próbek nowej odpowiedzi impulsowej filtru dla każdego wymaganego opóźnienia w opraciu o wielomiany o współczynnikach niezależnych od opóźnienia. Prowadzi to do znacznego zmniejszenia kosztów numerycznych implementacji w zastosowaniach wymagających częstej zmiany opóźnienia...
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DYNAMIC SYSTEMS AND APPLICATIONS
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Local material symmetry group for first- and second-order strain gradient fluids
PublicationUsing an unified approach based on the local material symmetry group introduced for general first- and second-order strain gradient elastic media, we analyze the constitutive equations of strain gradient fluids. For the strain gradient medium there exists a strain energy density dependent on first- and higher-order gradients of placement vector, whereas for fluids a strain energy depends on a current mass density and its gradients....
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Combined Heat & Power Generating Systems
PublicationSteam cycles in combined heat and power plants. Efficiency of combined heat and power systems. Characteristics of steam-turbine CHP plants. Choice of equipment in CHP generating systems. Economic effects of combined heat and power production. Costs and energy produced CHP generating systems. Future development trends in CHP generating systems.
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Method of lines for nonlinear first order partial functional differential equations.
PublicationClassical solutions of initial problems for nonlinear functional differential equations of Hamilton--Jacobi type are approximated by solutions of associated differential difference systems. A method of quasilinearization is adopted. Sufficient conditions for the convergence of the method of lines and error estimates for approximate solutions are given. Nonlinear estimates of the Perron type with respect to functional variables...