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Search results for: — COMPUTER-AIDED ENGINEERING, DESIGN AUTOMATION, FINITE-ELEMENT METHOD (FEM), PARAMETRIC MACROMODELS, PARAMETRIC MODEL-ORDER REDUCTION (PMORE).
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A FEM membrane model of human fascia-synthetic implant system in a case of a stiff ventral hernia orifice
PublicationPraca prezdstawia model matematyczny układu tkanka ludzka - implant syntetyczny w postaci tzw. siatki w leczeniu przepuklin brzusznych. Implant jest tu moelowany jako struktura membranowa. Ocena wpływu danych materiałowych oraz wstępnego napięcia na zachowanie pracującej membrany po implantacji została przedstawiona na podstawie analizy wrażliwości. Pracę podsumowują pewne wskazówki dla chirurgów implantujących siatki.
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Update a simple hypoplastic constitutive model
PublicationW artykule omówiono uproszczona formę hipoplastycznego konstytutywnego prawa materiałowego do opisu zachowania się materiałów granulowanych. Wykonano symulacje testów elementów i porównano wyniki z doświadczeniami.
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Macromodels in the frequency domain analysis of microwave resonators.
PublicationW artykule zaprezentowana jest technika włączania makromodeli do metod siatkowych sformułowanych w dziedzinie częstotliwości.W odróżnieniu do poprzednich, nowy schemat nie wprowadza zależności częstotliwościowej do macierzy systemowej i dzięki temu może być użyta w analizie rezonatorów. Testy numeryczne pokazują wzrost dokładności obliczeń w szerokim zakresie częstotliwości, przy czym właściwości zbieżności iteracyjnego algorytmu...
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Application of linear buckling sensitivity analysis to economic design of cylindrical steel silos composed of corrugated sheets and columns
PublicationThe paper deals with global stability of steel cylindrical silos composed of corrugated walls and vertical columns with loads imposed by a bulk solid following Eurocode 1. The optimum silo design with respect to the steel weight was based on a sensitivity analysis method. The changes of silo column profiles at each design step were performed by means of influence lines for the buckling load factor due to the unit column bending...
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A computer-based training program : Refrigerating Plant as an example of recent didactic means in maritime engineering education
PublicationW referacie przedstawiono możliwości kształcenia prowadzonego w oparciu o program komputerowy typu cbt - Chłodnia Prowiantowa. Omówiono jego strukturę i zawartość merytoryczną. Przedstawiono sposób oceny osoby szkolonej wykorzystującej ten program. Wskazano na korzyści płynące z zastosowania programów tego typu w kształceniu mechaników okrętowych. Materiał bogato ilustrowano przykładami ekranów z prezentowanego programu.
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Numerical tests of time-stepping schemes in the context of FEM for 6-field shell dynamics
PublicationThe paper deals with integration of dynamic equations of irregular shells performed with relatively long time steps. Numerical instability appearing often in this kind of analysis motivated the authors to present some studies based on numerical tests referring to convergence problems of finite element analysis as well the applied stability conditions. The analysis is carried out on simulations of shell dynamics with the where the...
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VARIANT DESIGNING IN the PRELIMINARY SMALL SHIP DESIGN PROCESS
PublicationShip designing is a complex process, as the ship itself is a complex, technical multi-level object which operates in the air/water boundary environment and is exposed to the action of many different external and internal factors resulting from the adopted technical solutions, type of operation, and environmental conditions. A traditional ship design process consists of a series of subsequent multistage iterations, which gradually...
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Fragmentation of Hydrographic Big Data Into Subsets During Reduction Process
PublicationThe article presented problems of fragmentation of hydrographic big data into smaller subsets during reduction process. Data reduction is a processing of reduce the value of the data set, in order to make them easier and more effective for the goals of the analysis. The main aim of authors is to create new reduction method. The article presented the first stage of this method – fragmentation of bathymetric data into subsets. It...
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The Principles of Model Building Concepts Which Are Applied to the Design Patterns for Smart Cities
PublicationThe involvement of citizens into decision-making processes is one of the main features of smart cities. Such commitment is reflected in the form of requirements towards the city, and the benefits which are expected from the city. Requirements and benefits are thus the primary language of communication between decision-makers and urban residents. To develop such a language, it becomes necessary to develop design patterns for Smart...
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Experiments on Preserving Pieces of Information in a Given Order in Holographic Reduced Representations and the Continuous Geometric Algebra Model
PublicationGeometric Analogues of Holographic Reduced Representations (GAc, which is the continuous version of the previously developed discrete GA model) employ role-filler binding based on geometric products.Atomic objects are real-valued vectors in n-dimensional Euclidean space and complex statements belong to a hierarchy of multivectors. The property of GAc and HRR studied here is the ability to store pieces of information in a given...
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On some properties of 2d spectral finite elements in problems of wave propagation
PublicationW pracy przedstawiono sformułowanie dwuwymiarowych elementów spektralnych stosowanych w symulacji propagacji fal prowadzonych. Zbadano własności tych elementów pod kątem występowania form pasożytniczych, odporności na dystorsję siatki oraz zbadano wpływ kształtu elementu na krzywe dyspersji
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Description Logic As A Common Software Engineering Artifacts Language
PublicationDescription logic is proposed as a powerful language able to support chosen software engineering process tasks like: requirements engineering, software architecture definition, software design and configuration management. To do this there is presented a correspondence between description logic and UML. Description logic based integrated software engineering process framework is proposed which owing to automatic knowledge inferring...
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On the convergence of a finite-difference discretization à la Mickens of the generalized Burgers–Huxley equation
PublicationIn this note, we establish the property of convergence for a finite-difference discretization of a diffusive partial differential equation with generalized Burgers convective law and generalized Hodgkin–Huxley reaction. The numerical method was previously investigated in the literature and, amongst other features of interest, it is a fast and nonlinear technique that is capable of preserving positivity, boundedness and monotonicity....
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High quality speech coding using combined parametric and perceptual modules. [Kodowanie sygnału mowy z zachowaniem wysokiej jakości przy wykorzystaniu modułu parametrycznego i perceptualnego]
PublicationW komunikacie zaprezentowano nową metodę hybrydowego kodowania sygnału mowy. Techniki kodowania parametrycznego oraz perceptualnego zostały wykorzystane w celu zapewnienia wysokiej jakości kodowania sygnału mowy. Przedstawiono wyniki badań dla dwóch architektur kodeka. Jedna z nich bazuje na algorytmie pozwalajacym wyodrębnić składowe dźwięczne, bezdźwięczne oraz transjenty. Składowe dźwięczne kodowane są metodą perceptualną, bezdźwięczne...
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3-D finite-difference time-domain modelling of ground penetrating radar for identification of rebars in complex reinforced concrete structures
PublicationThis paper presents numerical and experimental investigations to identify reinforcing bars using the ground penetrating radar (GPR) method. A novel element of the paper is the inspection of different arrangements of reinforcement bars. Two particular problems, i.e. detection of few adjacent transverse bars and detection of a longitudinal bar located over or under transverse reinforcement, have been raised. An attention was also...
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Projekt optymalnego łuku poziomego jako element nauczania kształtowania układów geometrycznych toru
PublicationAspekt geometryczny stanowi ważny element w nauczaniu projektowania dróg szynowych na studiach 1-go i 2-go stopnia na Wydziale Inżynierii Lądowej i Środowiska Politechniki Gdańskiej. Podstawowym, najczęściej spotykanym w praktyce elementem linii kolejowej w planie jest łuk poziomy z krzywymi przejściowymi. Z tego względu na Wydziale Inżynierii Lądowej i Środowiska Politechniki Gdańskiej wdrożono ćwiczenie projektowe ujmujące to...
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Multicriteria optymization method for yacht design
PublicationArtykuł dotyczy optymalizacji wielokryterialnej projektowania innowacyjnego systemu jachtowego w taki sposób by osiągnąć polepszone zachowanie dynamiczne w dowolnych warunkach nawigacji morskiej. W artykule skoncentrowano się na komputerowej symulacji, modelowaniu i optymalizacji matematycznego modelu jachtu w różnych warunkach żeglowania w celu poprawy zdolności manewrowania i zwiększenia szybkości. Przeprowadza się symulację...
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Tribological Properties of Ni-P/Si3N4 Nanocomposite Layers Deposited by Chemical Reduction Method on Aluminum Alloy AW-7075
PublicationThe article presents the results of tribological tests of Ni-P/Si3N4 nanocomposite and Ni-P nickel layers deposited on the AW-7075 aluminum alloy by chemical reduction method, and the AW-7075 alloy without coating. Nanocomposite layers were produced using Si3N4 siliconnitride in the form of a polydisperse powder whose particle sizes ranged from 20 to 25 nm. The influence of the content of the dispersion phase layer material on...
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Industry 4.0—Supporting Industry in Design Solutions—All-in-One Computer Cover
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The effects of graphical interface design characteristics on human–computer interaction task efficiency
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Nonlinear FEM 2D failure onset prediction of composite shells based on 6-parameter shell theory
PublicationWithin the framework of the nonlinear 6-parameter shell theory with the drilling rotation and asymmetric stress measures, the modifications of Tsai-Wu and Hashin laminate failure initiation criteria are proposed. These improvements enable to perform first ply failure estimations taking into account the non-symmetric stress measures. In order to check the validity of the proposed criteria, finite element analyses are performed with...
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The dynamic analysis of a cracked Timoshenko beam by the spectral element method
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Rigid ninite element method for dynamics of flexible multibody systems
PublicationW pracy przedstawiono metodę sztywnych elementów skończonych w nowym sformułowaniu bazującym na przekształceniach jednorodnych wraz ze złączowymi współrzędnymi. Omówiono klasyczną i zmodyfikowaną wersję metody, które różnią się nie tylko liczbą stopni swobody, ale także różniczkowaniem równań ruchu. Każda z wersji może być zastosowana do analizy liniowych i nieliniowych drgań, co pokazano na przykładzie belki wspornikowej.
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Expedited EM-Driven Design of Miniaturized Microwave Hybrid Couplers Using Surrogate-Based Optimization
PublicationMiniaturization of microwave hybrid couplers is important for contemporary wireless communication engineering. Using standard computer-aided design methods for development of compact structures is extremely challenging due to a general lack of computationally efficient and accurate simulation models. Poor accuracy of available equivalent circuits results from neglecting parasitic cross-couplings that greatly affect the performance...
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Book review: Simulation-Driven Design Optimisation and Modelling for Microwave Engineering
PublicationCelem książki jest przedstawienie aktualnego stanu badań dotyczących projektowania układów mikrofalowych poprzez modelowanie i optymalizacje wspomagane symulacjami elektromagnetycznymi. Grupa międzynarodowych ekspertów zajmujących się rożnymi aspektami komputerowo wspomaganego projektowania układów mikrofalowych, podsumowuje i dokonuje przeglądu ostatnich osiągnięć w tej dziedzinie oraz przedstawia szereg praktycznych zastosowań....
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Surface finite viscoelasticity and surface anti-plane waves
PublicationWe introduce the surface viscoelasticity under finite deformations. The theory is straightforward generalization of the Gurtin–Murdoch model to materials with fading memory. Surface viscoelasticity may reflect some surface related creep/stress relaxation phenomena observed at small scales. Discussed model could also describe thin inelastic coatings or thin interfacial layers. The constitutive equations for surface stresses are...
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Accelerated design optimization of miniaturized microwave passives by design reusing and Kriging interpolation surrogates
PublicationElectromagnetic (EM) analysis has become ubiquitous in the design of microwave components and systems. One of the reasons is the increasing topological complexity of the circuits. Their reliable evaluation—at least at the design closure stage—can no longer be carried out using analytical or equivalent network representations. This is especially pertinent to miniaturized structures, where considerable EM cross-coupling effects occurring...
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Design thinking (DT) for the design and planning education of engineer-architects
PublicationEngineers are facing new challenges connected with globalisation, digitisation and the increased complexity of the design process. This calls for new, more interdisciplinary and user-oriented approaches to problem- solving. In this article, the authors analyse design thinking (DT) as a method to support the education of engineers specialising in architecture and urban planning. Identified in this study are the opportunities this...
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Discussion on “Dynamic soil-structure interaction: A three-dimensional numerical approach and its application to the Lotung case study”. Poor performance of the HSS model
PublicationThe Hardening Soil Small (HSS) is a constitutive model being extension to the well established Hardening Soil Model (HS) accounting for the nonlinearity of small strain stiffness. It is implemented in commercial finite element computer codes for geotechnical analyses and used widely in research and design. The article deals with a problem known as overshooting after very small load reversals. It induces much higher stiffness than...
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Laboratory Determination of Burger's Model Parameters for Visco-elastic Analysis of Road Pavement Materials
PublicationBurger's Model is one of those models that describes performance of asphalt mixtures. Its parameters can be used in road construction analysis based on visco-elastic properties in wide variety of temperatures using dedicated programs (e.g. Veroad) or in Finite Element Method (FEM). Parameters of Burger's Model can be used for example in prediction of low temperature cracking in low winter temperatures or permanent deformation...
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Prediction of metal deformation due to line heating; an alternative method of mechanical bending, based on artificial neural network approach
PublicationLine heating is one of the alternative methods of forming metals and this kind of forming uses the heating torch as a source of heat input. During the process, many parameters are considered like the size of the substrate, thickness, cooling method, source power intensity, the travel speed of the power source, the sequence of heating, and so on. It is important to analyze the factors affecting the...
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Silica nanospheres as a key process element in the Green engineering for the synthesis of carbon nanotubes as a supercapacitors additives
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The model of photovoltaic phenomenon in thin inhomogeneously organic film
PublicationW pracy przedstawiono model zjawiska fotowoltaicznego w obecności gradientu pułapek nośników ładunku. Zakładając, że długość dyfuzji ekscytonów związana jest z koncentracją pułapek, wykazano, że napięcie fotowoltaiczne silnie zależy od gradientu koncentracji pułapek.
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Analysis of Validation and Simplification of Timber-Frame Structure Design Stage with PU-Foam Insulation
PublicationThe transition from experimental studies to the realm of numerical simulations is often necessary for further studies, but very difficult at the same time. This is especially the case for extended seismic analysis and earthquake-resistant design. This paper describes an approach to moving from the experimental testing of an elementary part of a wood-frame building structure to a numerical model, with the use of a commercial engineering...
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Simulation model of IPMSM drive with rotor position estimator
PublicationThe paper presents a simulation model of electric drive consisting of: IPMSM motor, inverter and digital controller. The model was designed in Mathlab/Simulink. By modelling of the controller its discrete operation was taken into account in order to simulate precisely a specific sensorless control algorithm. A method for estimation of angular rotor position was proposed. Its mathematical algorithm was explained and errors were...
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Human Resource Management Digitalisation in Multidisciplinary Ship Design Companies
PublicationThe digitalisation in the ship design sector is currently applied to the design process itself and is well defined, partially standardised and practically implemented by both independent design companies and the design departments of shipyards. The situation is similar in other sectors of engineering. However, the requirements for the digitalisation of other processes in design and engineering companies have not previously been...
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Expedited simulation-driven design optimization of UWB antennas by means of response features
PublicationIn this work, a method for fast design optimization of broadband antennas is considered. The approach is based on a feature-based optimization (FBO) concept where reflection characteristics of the structure at hand are formulated in terms of suitably defined feature points. Redefinition of the design problem allows for reducing the design optimization cost, because the dependence of feature point coordinates on antenna dimensions...
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Investigations of size effect in concrete at aggregate level - experiments and calculations results using discrete element method
PublicationSize effect is a fundamental phenomenon in concrete. It is characterised by decreasing strength and increasing brittleness of concrete with increasing size. The thesis includes experimental and theoretical elements. The main goal of the thesis were investigations of a size effect at the aggregate level by taking fracture into account with the discrete element method (DEM) for various failure modes. Comprehensive experiments on...
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A Compact Basis for Reliable Fast Frequency Sweep via the Reduced-Basis Method
PublicationA reliable reduced-order model (ROM) for fast frequency sweep in time-harmonic Maxwell’s equations by means of the reduced-basis method is detailed. Taking frequency as a parameter, the electromagnetic field in microwave circuits does not arbitrarily vary as frequency changes, but evolves on a very low-dimensional manifold. Approximating this low-dimensional manifold by a low dimension subspace, namely, reduced-basis space, gives...
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Controlling computer by lip gestures employing neural network
PublicationResults of experiments regarding lip gesture recognition with an artificial neural network are discussed. The neural network module forms the core element of a multimodal human-computer interface called LipMouse. This solution allows a user to work on a computer using lip movements and gestures. A user face is detected in a video stream from a standard web camera using a cascade of boosted classifiers working with Haar-like features....
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Application of the ‘CPT 2012’model of AFNOR standard for column design in Poland–Jazowa case study
Publicationhis paper presents the ‘CPT 2012’ model incorporated into the AFNOR NF P94-262:2012-07, French standard for pile design fully compatible with Eurocode 7, to the wider Polish audience. The bearing capacity of three reference columns for Vistula Marshlands have been calculated according to ‘CPT 2012’ model and AFNOR recommendations. Then, the design resistances have been compared with ultimate column bearing capacity measured during...
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THE INFLUENCE OF POLYMER STRIPS IN REDUCTION OF A STEEL GRANDSTAND VIBRATIONS
PublicationGrandstands are types of structures commonly used during sport events or music concerts. Dynamic loads generated by crowd movement may have significant influence on human perception as well as may lead to the destruction of a structure. Lighter and more slender structural steel members are more easily excitable by spectators. If the synchronized movement is tuned with the natural frequency of the affected part of the structure,...
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Modelling of in-plane wave propagation in a plate using spectral element method and Kane-Mindlin theory with application to damage detection
PublicationThis paper presents results of experimental and numerical analyses of in-plane waves propagatingin a 5 mm-thick steel plate in the frequency range of 120-300 kHz. For such a thickness/frequency ratio,extensional waves reveal dispersive character. To model in-plane wave propagation taking into account thethickness-stretch effect, a novel 2D spectral element, based on the Kane-Mindlin theory, was formulated. Anapplication of in-plane...
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Design of compound curves adapted to the satellite measurements
PublicationThe paper deals with a novelty related to the design of a region for an alternative railway track direction adequate for mobile satellite measurements. The new approach may become particularly useful in the design of the existing track axis control when the determination of both the main track directions becomes impossible. The only solution in that case is to apply to the geometrical system two circular arcs of a different radius,...
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Non-linear FEM analysis of pounding-involved response of buildings under non-uniform earthquake excitation
PublicationThe aim of the paper is to show the results of the study investigating the influence of non-uniform earthquake excitation, due to spatial seismic effects connected with the propagation of seismic wave, on the pounding-involved response of two buildings. The three-dimensional non-linear FEM analysis has been conducted using the detailed models of colliding structures. Acceleration records for different structural supports have been...
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Model of distributed learning objects repository for a heterogenic internet environment
PublicationW artykule wprowadzono pojęcie komponentu edukacyjnego jako rozszerzenie obiektu edukacyjnego o elementy zachowania (metody). Zaproponowane podejście jest zgodne z paradygmatem obiektowym. W oparciu o komponent edukacyjny zaprojektowano model budowy repozytorium materiałów edukacyjnych. Model ten jest oparty o usługi sieciowe i rejestry UDDI. Komponent edukacyjny oraz model repozytorium mogą znaleźć zastosowanie w konstrukcji zbiorów...
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Micromouse robot - technical design and construction
PublicationW ostatnich latach obserwuje się intensywny rozwój robotyki. Roboty znajdują zastosowanie w różnych gałęziach przemysłu i życiu codziennym. Ich projektowanie wymaga interdyscyplinarnej wiedzy obejmującej obszary mechaniki, elektroniki, metrologii, automatyki i informatyki. W artykule przedstawiono poszczególne etapy wykonania robota typu Micromouse. Jest to specyficzne urządzenie, którego zadaniem jest zbadanie labiryntu, dotarcie...
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A study of a reduction of a micro- and nanometric bismuth oxide in hydrogen atmosphere
PublicationA reduction of bismuth oxide in hydrogen atmosphere was investigated. The reaction was performed with a material in various structural forms: powder: with micrometric grains, powder with nanometric grains and powder pressed into pellets. The process was performed in both isothermal and non-isothermal conditions. An activation energy of the reaction calculated with Friedman method was found to be about 85 kJ/mol for the reduction...
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2D lattice model for fracture in brittle materials
PublicationW artykule przedstawiono wyniki obliczeń propagacji rys w elementach betonowych przy zastosowaniu modelu dyskretnego opartego na ruszcie belkowym. Obliczenia wykonano dla różnych problemów brzegowych.
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Heuristic scheduling algorithms for uniform load of computer system
PublicationW pracy zaprezentowano opracowany heurystyczny algorytm szeregowania zadań UNILO (ang. UNIform LOad - jednakowe obciążenie), umożliwiający redukcję całkowitego zapotrzebowania na moc obliczeniową systemu komputerowego bez pogarszania jego wydajności. Algorytm ten realizuje takie przydzielenie zadań obliczeniowych do poszczególnych jednostek (procesorów), aby zapewnić ich jednakowe obciążenie. Opracowany algorytm został zweryfikowany...