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Search results for: dynamic-algebraic equations
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On some constitutive equations for micropolar plates
PublicationW pracy porównano równania konstytutywne dla płyt podane przez Altenbacha i Eremeyeva. Na podstawie ich wyprowadzeń określono zakres zmienności współczynnika momentów owinięcia i jego możliwy wpływ na wyniki otrzymane w rozwiązaniach MES w zakresie liniowym
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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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Systems of differential equations with a singular matrix
PublicationPraca dotyczy układów równań różniczkowych z macierzą osobliwą. Szczególnymi przypadkami takich układów są równania różniczkowo-algebraiczne. Korzystając z odpowiedniej nierówności różniczkowej dla układów równań i metody quasi linearyzacji pokazano, iż odpowiednie monotoniczne ciągi są zbieżne do rozwiązania naszego problemu i jest to zbieżność kwadratowa. O funkcji f występującej po prawej stronie zagadnienia zakładano...
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Differential equations with integral boundary conditions
PublicationStosuje się metodę iteracji monotonicznych opartą na dolnym i górnym rozwiązaniu. Przy jednostronnym warunku Lipschitza uzyskano pewne wyniki dotyczące rozwiązań zwyczajnych równań różniczkowych z całkowym warunkiem brzegowym. Sformułowano warunki dostateczne na istnienie jedynego rozwiązania (lub rozwiązań ekstremalnych) w pewnym segmencie. Podano przykłady ilustrujące przyjęte założenia.
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On integro-differential equations with delayed arguments
PublicationPraca dotyczy problemów różniczkowo-całkowych z warunkami początkowymi oraz brzegowymi typu okresowego. Podano warunki na istnienie i jednoznaczność rozwiązania. Badania dotyczyły również nierówności różniczkowo-całkowych z argumentami typu opóżnionego. Podano przykłady, które mogą mieć zastosowanie w problemach inżynierskich.
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Dynamic Compatibility Matching of Services for Distributed Workflow Execution
PublicationThe paper presents a concept and an implementation of dynamic learn-ing of compatibilities of services used in a workflow application. While services may have the same functionality, they may accept input and produce output in different formats. The proposed solution learns matching of outputs and inputs at runtime and uses this knowledge in subsequent runs of workflow applications. The presented solution was implemented in an...
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An Evaluation Engine for Dynamic Ranking of Cloud Providers
PublicationThe paper focuses on creation of an effective dynamic ranking service for IaaS, PaaS and SaaS cloud providers. It considers building a quality model for this purpose along with definition of quality measure- ment procedures. The paper discusses several techniques known from already existing price comparison engines that could be modified and adopted for comparison of cloud providers. A technique for filtering measured data is proposed,...
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Designing Particle Kalman Filter for Dynamic Positioning
PublicationThe article presents a comparative analysis of two variants of the Particle Kalman Filter designed by using two different ship motion models. The first filter bases only on the kinematic model of the ship and can be used in many types of vehicles, regardless of the vehicle dynamics model. The input value to the filter is the noisy position of the ship. The second filter makes use of the kinematic and dynamic models of the moving...
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Investigation of behaviour of metal structures with polymer dampers under dynamic loads
PublicationA large number of accidents concerning structures subjected to dynamic loads have been recently observed. One of the examples of such a structure is a temporary steel grandstand erected using scaffolding system. Dynamic load that is generated by crowd movement has a significant influence on the behaviour of the structure and may lead to excessive structural vibrations. The aim of the study is to consider the idea of using polymer...
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Effective highly accurate time integrators for linear Klein-Gordon equations across the scales
PublicationWe propose an efficient approach for time integration of Klein-Gordon equations with highly oscillatory in time input terms. The new methods are highly accurate in the entire range, from slowly varying up to highly oscillatory regimes. Our approach is based on splitting methods tailored to the structure of the input term which allows us to resolve the oscillations in the system uniformly in all frequencies, while the error constant...
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Effective highly accurate time integrators for linear Klein-Gordon equations across the scales
PublicationWe propose an efficient approach for time integration of Klein-Gordon equations with highly oscillatory in time input terms. The new methods are highly accurate in the entire range, from slowly varying up to highly oscillatory regimes. Our approach is based on splitting methods tailored to the structure of the input term which allows us to resolve the oscillations in the system uniformly in all frequencies, while the error constant...
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Dynamic Bankruptcy Prediction Models for European Enterprises
PublicationThis manuscript is devoted to the issue of forecasting corporate bankruptcy. Determining a firm’s bankruptcy risk is one of the most interesting topics for investors and decision-makers. The aim of the paper is to develop and to evaluate dynamic bankruptcy prediction models for European enterprises. To conduct this objective, four forecasting models are developed with the use of four different methods—fuzzy sets, recurrent and...
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Investigation of buckling resistance of columns using non-linear static and dynamic analysis
PublicationThe aim of this paper is to investigate the stability process in an axially compressed column using a static and dynamic finite element analysis by taking both the geometric and material non-linearity into account. The perfect column and column with geometric imperfections were analysed. The linear buckling analyses were used to obtain the lowest buckling load and shapes of buckled forms that were taken into account as initial...
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On–line Parameter and Delay Estimation of Continuous–Time Dynamic Systems
PublicationThe problem of on-line identification of non-stationary delay systems is considered. The dynamics of supervised industrial processes are usually modeled by ordinary differential equations. Discrete-time mechanizations of continuous-time process models are implemented with the use of dedicated finite-horizon integrating filters. Least-squares and instrumental variable procedures mechanized in recursive forms are applied for simultaneous...
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Successive Iterative Method for Higher-Order Fractional Differential Equations Involving Stieltjes Integral Boundary Conditions
PublicationIn this paper, the existence of positive solutions to fractional differential equations with delayed arguments and Stieltjes integral boundary conditions is discussed. The convergence of successive iterative method of solving such problems is investigated. This allows us to improve some recent works. Some numerical examples illustrate the results.
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The dynamic signature verification using population-based vertical partitioning
PublicationThe dynamic signature is an attribute used in behavioral biometrics for verifying the identity of an individual. This attribute, apart from the shape of the signature, also contains information about the dynamics of the signing process described by the signals which tend to change over time. It is possible to process those signals in order to obtain descriptors of the signature characteristic of an individual user. One of the methods...
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Description of the solution set of the von Karman equations for a circular plate in a small neighbourhood of a simple bifurcation point
PublicationW niniejszej pracy badamy równania von Karmana dla cienkiej, sprężystej, kołowej płyty na sprężystym podłożu, poddawanej działaniu sił ściskających wzdłuż brzegu. Są to równania różniczkowe cząstkowe IV rzędu. Stosując metody analizy nieliniowej, opisujemy zbiór rozwiązań równań von Karmana w małym otoczeniu jednokrotnego punktu bifurkacji.Badania były finansowane przez grant nr 1 P03A 042 29.
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Application of dynamic impedance spectroscopy to scanning probe microscopy.
PublicationDynamic impedance spectroscopy, designed for measuring nonstationary systems, was used in combination with scanning probe microscopy. Using this approach, impedance mapping could be carried-out simultaneously with topography scanning. Therefore, correlation of electrical properties with particular phases of an examined sample was possible. The sample used in this study was spheroidal graphite cast iron with clearly defined phases...
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Dynamic Signature Vertical Partitioning Using Selected Population-Based Algorithms
PublicationThe dynamic signature is a biometric attribute used for identity verification. It contains information on dynamics of the signing process. There are many approaches to the dynamic signature verification, including the one based on signature partitioning. Partitions are the regions created on the basis of signals describing the dynamics of the signature. They contain information on the shape of the signature characteristic of a...
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Joanna Janczewska prof. dr hab.
PeopleJoanna Janczewska obtained her PhD degree at the University of Gdansk in 2002. From October 1999 to September 2004 she was an assistant at the University of Gdansk. Since October 2004 she has been an assistant professor at the Gdansk University of Technology. Moreover, from October 2008 to September 2010 she had a visiting position in the Institute of Mathematics of the Polish Academy of Sciences. Her mathematical interests...
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Wideband Off-Body Channel Characteristics with Dynamic User
PublicationThis paper presents the preliminary results of a dynamic off-body channel characterisation study, based on wideband measurements at 5.8 GHz in an indoor environment. The Channel Impulse Response (CIR) was measured for a scenario with the user approaching and departing from the off-body antenna. A CIR deconvolution procedure was performed jointly in two polarisations, and the received signal power, Cross-Polarisation Discrimination...
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Effect of pavement roughness and vehicle dynamic loads on decrease of fatigue life of flexible pavements
PublicationDue to the fact that pavement surfaces are not ideally even, dynamic loads of vehicle axles deviate from static loads. Higher dynamic loads contribute to faster pavement distress. The distribution of dynamic loads is similar to normal distribution and can be described by static load and factors DI (dynamic impact) and DLC (dynamic load coefficient). With the deterioration of pavement condition its evenness decreases as well and...
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Performance evaluation of unified memory and dynamic parallelism for selected parallel CUDA applications
PublicationThe aim of this paper is to evaluate performance of new CUDA mechanisms—unified memory and dynamic parallelism for real parallel applications compared to standard CUDA API versions. In order to gain insight into performance of these mechanisms, we decided to implement three applications with control and data flow typical of SPMD, geometric SPMD and divide-and-conquer schemes, which were then used for tests and experiments. Specifically,...
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History-based dynamic weight voting for multi-agent systems
PublicationTaking decision in multi-agent systems may involve voting. Two basic voting protocols are surveyed in the paper. Then, a new history-based dynamic weight voting is proposed. This voting protocol allows for identification of the agents which contribute to the correct system decision. The proposed solution is contrasted with majority voting and with weighted average voting, to show its advantages
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Approximate solution for Euler equations of stratified water via numerical solution of coupled KdV system
PublicationWe consider Euler equations with stratified background state that is valid for internal water waves. The solution of the initial-boundary problem for Boussinesq approximation in the waveguide mode is presented in terms of the stream function. The orthogonal eigenfunctions describe a vertical shape of the internal wave modes and satisfy a Sturm-Liouville problem. The horizontal profile is defined by a coupled KdV system which is...
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Finite element modeling of plastic hinges based on ductility demand-capacity method using nonlinear material for dynamic analysis
PublicationThe article discusses modeling plastic hinges in reinforced concrete interme-diate supports using finite elements methods. The ductility demand-capacitymethod was used to determine the geometrical parameters of cross-section plas-ticization zones, their ability to move and rotate, as well as their ductility. Dueto the varied geometry and stiffness of the supports and their nonlinear behav-ior under dynamic load, this method was...
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Identification of diagnostic parameter sensitivity during dynamic processes of a marine engine
PublicationChanging some parameters of the engine structure alters the emission of harmful components in the exhaust gas. This applies in particular to the damage of charge exchange system as well as fuel system and engine supercharger. These changes are much greater during the dynamic states and their accompanying transitional processes. The different sensitivity of diagnostic parameters to the same force, coming from the engine structure, but...
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Fading Modelling in Dynamic Off-Body Channels
PublicationThis paper presents an off-body fading channel model for Body Area Networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in an indoor environment (a medium-size room with furniture, mostly consisting of wooden tables and chairs) have been measured:...
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Control System Design for Dynamic Positioning using Vectorial Backstepping
PublicationThe problem of synthesis a dynamic positioning system for low frequency model of surface vessel was considered in this paper. The recursive vectorial backstepping control design was used to keep a fixed position and heading in presence of wave disturbances. The passive observer was introduced to smooth the measurements and to estimate the velocities needed for the control algorithm. The computer simulation results were given to...
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Assessment of dynamic characteristics of thin cylindrical sandwich panels with magnetorheological core
PublicationBased on the equivalent single-layer linear theory for laminated shells, free and forced vibrations of thin cylindrical sandwich panels with magnetorheological core are studied. Five variants of available magnetorheological elastomers differing in their composition and physical properties are considered for smart viscoelastic core. Coupled differential equations in terms of displacements based on the generalized kinematic hypotheses...
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The consequences of dynamic BPM
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Development of dynamic method for evaluation of inhibition efficiency on the example of 8-hydroxyquinolin
PublicationSelection of a proper inhibitor should be based on the evaluation of its mechanism and effective concentrations. Mechanism of inhibition usually has dynamic character due to changing physicochemical conditions of the environment and corroding metal surface. Most of actually used methods are stationary or contain assumptions which highly influences obtained values. Development of new dynamic method, based on modified EIS, allows...
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Dynamic Analysis of the Turnout Diverging Track for HSR with Variable Curvature Sections
PublicationThe paper presents an analytical method of identifying the curvature of the turnout diverging track consisting of sections of varying curvature. Both linear and nonlinear (polynomial) curvatures of the turnout diverging track are identified and evaluated in the paper. The presented method is a universal one, it enables to assume curvature values at the beginning and end point of the geometrical layout of the turnout. The results...
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Composite sandwich footbridge - measured dynamic response vs. FEA
PublicationThe paper describes a process of in situ dynamic tests of a composite sandwich footbridge before its accepta-tion for exploitation in real traffic conditions. It is only a part of a big research task that includes design, manufacture and introduce practical application of the bridge. The in situ measured natural modes and fre-quencies are compared with numerically determined ones. Finite element analysis is established to estimate...
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The dataset of coupling coefficients for rotating receiver of multicoil dynamic wireless power transfer system
Open Research DataThe provided dataset is part of the simulation results shown in related journal paper "Optimal Rotating Receiver Angles Estimation for Multicoil Dynamic Wireless Power Transfer".
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Fracture mechanics model of cutting power versus widespread regression equations while wood sawing with circular saw blades
PublicationA comparison of the theoretical cutting power consumption results forecasted with the model (FM_CM model) which include work of separation (fracture toughness) in addition to plasticity and friction, and two widespread regression equations while wood sawing with circular saw blades has been described. in and cutting power consumption forecasted. In computations of the cutting power consumption during rip sawing of Scots pine wood...
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Boundary problems for differential equations with advanced arguments
PublicationDyskutowane są zagadnienia brzegowe dla równań różniczkowych z wyprzedzonymi argumentami. Przedstawione są warunki dostateczne istnienia quasirozwiązań i rozwiązań rozważanych zagadnień.
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Second-order differential equations with deviating arguments
PublicationPodane zostały warunki dostateczne na istnienie kwazi-rozwiązań oraz na istnienie jedynego rozwiązania dla równań różniczkowych rzędu drugiego z warunkami brzegowymi i odchylonymi argumentami. Otrzymane wyniki zilustrowano przykładami i wykresami.
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First-order impulsive functional differential equations
PublicationPraca dotyczy problemów istnienia rozwiązań i kwazi-rozwiązań dla równań różniczkowych rzędu pierwszego z impulsami i nieliniowymi warunkami brzegowymi. Operator występujący w zagadnieniu jest typu opóźnionego. Badano również nierówności różniczkowe z impulsami związane z zagadnieniem wyjściowym. Otrzymane wyniki zilustrowano na przykładach.
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Green function diagonal for a class of heat equations
PublicationA construction of the heat kernel diagonal is considered as element of generalized zeta function theory, which gradient at the origin defines determinant of a differential operator in a technique for regularizing quadratic path integral. Some classes of explicit expressions of the Green function in the case of finite-gap potential coefficient of the heat equation are constructed. An algorithm and program for Mathematica are presented...
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Inverse Integration of the Open Channel Flow Equations
PublicationW artykule przedstawiono metodę obliczeń umożliwiającą całkowanie równań przepływu nieustalonego w kanałach otwartych (równań de Saint Venanta) wstecz. Dyskutowano także przydatność równania retencji w zagadnieniu sterowania przepływem.
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Advanced differential equations with nonlinear boundary conditions.
PublicationBadano problemy istnienia rozwiązań dla równań różniczkowych z nielinowymi warunkami brzegowymi. Podano też warunki dostateczne na istnienie rozwiązań ekstremalnych. Przedmiotem badań były również nierówności różniczkowe z wyprzedzonym argumentem.
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On delay differential equations with nonlinear boundary conditions
PublicationStosując metodę iteracji monotonicznych podano warunki dostateczne na istnienie kwazirozwiązań lub ekstremalnych rozwiązań rozpatrywanego zagadnienia. Problem jednoznaczności rozwiązania był również przedmiotem badań. Zajmowano się również nierównościami różniczkowymi z opóżnionymi argumentami.
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Relaxation methods for first order differential equations
PublicationPodano warunki dostateczne przy których iteracje otrzymane za pomocą metody relaksacyjnej są zbieżne do jedynego rozwiązania układu równań różniczkowych z warunkiem okresowym. Przykłady ilustrują otrzymane wyniki.
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Minimal and maximal solutions of differential equations with a singularmatrix.
PublicationPraca dotyczy zagadnień początkowych dla układów równań różniczkowych z macierzą osobliwą. Równania różniczkowo-algebraiczne są szczególnym przypadkiem takich zagadnień.Stosując metodę iteracji monotonicznych pokazano, że przy pewnych założeniach problem wyjściowy ma ekstremalne rozwiązania w pewnym sektorze.Teoretyczne rozważania zilustrowano przykładem.
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Monotone and numerical analytic- methods for differential equations.
PublicationPraca dotyczy problemu różniczkowo-całkowego (typu Fredholma) z ogólnym warunkiem początkowo-brzegowo-całkowym. W pierwszej części pracy, stosując metodę iteracji monotonicznych, sformułowano warunki dostateczne które gwarantują, że dyskutowany problem ma rozwiązanie ekstremalne w zbiorze generowanym przez dolne i górne rozwiązania. Rozważania teoretyczne poparto przykładem i dyskusją. W drugiej części pracy zastosowano metodę...
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Approximation of extremal solutions for functional differential equations
PublicationDyskutowane są równania różniczkowe funkcyjne z liniowym warunkiem brzegowym. Podano warunki dostateczne dla istnienia ciągów monotonicznych, aproksymujących rozwiązania ekstremalne badanych zagadnień.
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Ordinar differential equations with nonlinear boundary conditions
PublicationPraca dotyczy zwyczajnych równań różniczkowych z nieliniowymi warunkami brzegowymi. Sformułowano warunki dostateczne na istnienie rozwiązania (jedynego lub ekstremalnych) zakładając pewną regularność na prawe strony równania i warunek brzegowy. Warunki brzegowe typu okresowego lub antyokresowego są szczególnymi przypadkami ogólnego warunku dyskutowanego w tej pracy.
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Darboux-intergrable equations with non-abelian nonlinearities
PublicationWprowadzono nowa klasę nieliniowych równań dających się reprezentować przez warunki Darboux-kowariantności.