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Search results for: COMPUTER SIMULAION
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Internal imaging of concrete fracture based on elastic waves and ultrasound computed tomography
PublicationThe condition assessment of concrete structures belongs to the greatest challenges of non-destructive testing. Monitoring the fracture process of concrete and detecting cracks at the earliest possible stage is a vital aspect to ensure the safety of civil engineering objects. The use of ultrasound tomography enables imaging the internal structure of a tested element. This study aims at the visualization of fracture damage in concrete...
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A New Classification of the Morphology of Complete Ponticulus Posticus on Cone Beam Computed Tomography
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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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Simulation of temperature field in cylindrical boiling heating section
PublicationW pracy przedstawiono wyniki obliczeń cylindrycznej sekcji grzejnej. Biorąc pod uwagę geometrię i konstrukcję sekcji grzejnej zaprezentowano rozwiązania pola temperatury dla cylindrycznej sekcji grzejenej. W uzyskaniu rozwiązania posłużono się metodą elementów skończonych.
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Conditional simulation of spatiotemporal random fields of environmental contamination
PublicationArtykuł przedstawia metodę warunkowego modelowania przestrzenno-czasowych pól losowych w zagadnieniach środowiska naturalnego. Metoda ta może być wykorzystana do prognozy zanieczyszczenia w wybranych punktach w danym czasie na podstawie pomiarów wykonanych w innych miejscach i/lub w innym czasie. Analizę przeprowadzono na przykładzie zanieczyszczenia gruntu metalami ciężkimi.
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Thermal simulation of building performance with different loadbearing materials
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Hardware-in-the-loop simulation of the synchronization process of power generators
PublicationPrzedstawiono nowoczesne urządzenia do badań synchronizatorów automatycznych w warunkach laboratoryjnych. Szczególną uwagę poświęcono systemowi wizualizacji tych urządzeń )przy ich pomocymożliwa jest ciągła kontrola, sterowanie i wizualizacja procesem synchronizacji w systemie elektroenergetycznym.
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Numerical simulation of extreme flooding in a built-up area
PublicationPrzedstawiono dwie numeryczne symulacje propagacji gwałtownej fali powodziowej przez schematyczny model obszaru zabudowanego. Do obliczeń wykorzystano równania przepływu wody płytkiej. Wyniki obliczeń porównano z dostępnymi pomiarami wykonanymi w laboratorium hydraulicznym ENEL-CESI w Mediolanie. Uzyskano zadowalającą zgodność symulacji z eksperymentami.
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Numerical simulation of water drainage in double-porosity soils
PublicationArtykuł dotyczy modelowania przepływu wody w warunkach nienasyconych w gruntach o podwójnej porowatości, które są złożone z dwóch materiałów porowatych o bardzo różnych parametrach. przepływ w takich ośrodkach często charakteryzuje się powstawaniem lokalnych gradientów ciśnienia między obszarami dobrze isłaboprzepuszczalnymi.Przedstawiono matematyczny model przepływu wody w gruncie w strefie nienasyconej. Przepływ odbywa się w...
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Modeling and Simulation of Electric Motors Using Lightweight Materials
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Tracing of dynamic objects in distributed interactive simulation systems
PublicationDistributed interactive simulation systems require integration of several areas of computer science and applied mathematics to enable each individual simulation object to visualize effectively dynamic states of other objects. Objects are unpredictable,i.e., controlled by their local operators, and are remote, i.e., must rely on some transmission media to visualize dynamic scene from their local perspectives. The paper...
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Informational entropy in simulation of one-dimensional random fields
PublicationEntropia ciągłego rozkładu prawdopodobieństwa jest zdefiniowana jako funkcja liczby węzłów skalarnego pola losowego. W przykładzie numerycznym przedstawiono propagacje entropii w zagadnieniu reakcji sprężystego wspornika przy losowym obciążeniu.
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Planning and simulation studies of cellular-type manufacturing processes
PublicationZaproponowano metodę i algorytmy projektowania struktur organizacyjnych systemów wytwarzania typu gniazdowego, z wykorzystaniem zdefiniowanych modeli zapisu wiedzy technologicznej i zasad grupowej obróbki przedmiotów. Wyznaczono wskaźniki efektywności procesu grupowego przebiegającego w systemach gniazdowych z rozmieszczeniem komórkowym oraz funkcjonalnym stanowisk wg przyjętych formuł analitycznych. Zawarto wyniki zrealizowanych...
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Simulation of the profile wear of the tool in double wheel lapping
PublicationPrzedstawiono założenia modelowe do wyznaczenia zużycia profilowego narzędzia w docieraniu dwutarczowym. Rozkłady istotnych czynników kinematycznych (prędkości docierania i przyspieszenia stycznego) wpływających na zużycie docieraka zaprezentowane zostały dla różnych typów zakreślanych trajektorii.
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Simulation of the conformational flexibility of the mycodextran under external forces
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Simulation of Force Spectroscopy Experiments on Galacturonic Acid Oligomers
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Simulation and discretization of random field in the slip line method.
PublicationW pracy rozpatrywany jest problem nośności granicznej podłoża o własnościach stochastycznych przy obciążeniu spoczywającym na nim ciężkim sztywnym bloku.Opisano sposób generacji wielowymiarowego pola losowego oparty na diagonalizacji macierzy kowariancji przy wykorzystaniu macierzy dolnotrójkątnej .Szczególną uwagę zwrócono na wpływ dyskretyzacji ośrodka na rozwiązanie oraz jego zbieżność.
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Shell with random geometric imperfections simulation-based approach
PublicationPrzedstawiono analizę powłok z losowymi imperfekcjami. Zastosowano nieliniowe geometrycznie i materiałowo modele. Geometryczne imperfekcje opisano za pomocą pojedynczych zmiennych oraz pól losowych. Wykorzystano metodę Monte Carlo i metodę elementów skończonych. Zbadano wpływ różnych rozkładów prawdopodobieństwa imperfekcji geometrycznych na probabilistyczny rozkład nośności granicznej powłok. Zastosowane rozkłady ekstremalne imperfekcji...
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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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Model and laboratory simulation of a induction motor for diagnostic purposes
PublicationStatistics say that bearings are this part of induction motors which is most susceptible to damage. The equipment employed for bearing diagnostics usually makes use of vibrations as the criterion for technical condition of the bearings. A faulty bearing results in additional motor vibrations. They are reflected in the harmonic content of stator currents. In certain operating conditions the current signal is the sole source of information...
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Three-dimensional conceptual model for service-oriented simulation
Publicationn this letter, we propose a novel three-dimensional conceptual model for an emerging service-oriented simulation paradigm. The model can be used as a guideline or an analytic means to find the potential and possible future directions of the current simulation frameworks. In particular, the model inspects the crossover between the disciplines of modeling and simulation, service-orientation, and software/systems engineering. Finally,...
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Experimental Verification of Storm Sewer Transient Flow Simulation
PublicationThe paper focuses mainly on laboratory investigations of transient and transcritical flow in a single pipe of a sewer system. The aim of this paper is to present a comparison between pressure values calculated by an improved McCormack scheme and those measured at the hydraulic laboratory of the Gdansk University of Technology, which were observed inside a pipe in an experiment for water flow with pressurization. The analysis proves...
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Simulation of Parallel Applications on Large-scale Distributed Systems
PublicationThis chapter has a form of a review article in the field of simulating High-Performance Computing systems. We justify the need for a new versatile simulator considering heterogeneity, energy efficiency and reliability of HPC systems. We sketch the problems that need to be solved by such simulator and rationalize using discrete-event simulation for this purpose. Based on a review of existing discrete-event HPC simulation solutions...
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Selected aspects of heat recovery simulation in houseboat installations
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Agents in Simulation of Cyberattacks to Evaluate Security of Critical Infrastructures
PublicationIn the last years critical infrastructures have become highly dependent on the information technologies and exposed to cyberattacks. Because the effects of the attacks can be detrimental, it is crucial to comprehensively asses the security of the infrastructures' information systems. This chapter describes MAlSim - the simulator of malicious software based on software agents, developed for the needs of a testbed for critical infrastructures...
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Evolutionary Sets of Safe Ship Trajectories: simulation results
PublicationThe Evolutionary Sets of Safe Ship Trajectories is a method solving multi-ship encounter situations. For given positions and motion parameters the method finds a near optimal set of safe trajectories of all ships involved in an encounter. The paper briefly presents foundations of the method and focuses on simulation results for selected test cases based on the Baltic Basin. The computer simulations cover both open waters and restricted...
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Agent-based social network as a simulation of a market behaviour
PublicationRecent years and the outbreak of world's economic crisis in 2008 proved the crucial importance of reliable analysis of market dynamics. However, werarely apply models of proper detail level (the global prosperity forecast of 2007 can be seen as a grim proof). The behaviour of individuals and companies is far from being ideal and rational. Many claims that the economic paradigm of rational expectations (coming from J. Muth and R....
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Developing competences of IT project managers using simulation games
PublicationProject Management is a domain in which methodological approach is developing very rapidly. Project managers are required to present knowledge of the various methods of project management and apply them to the management of specific projects. It means that project managers must constantly develop their competence, mainly based on good practices from different formal methods of project management. The purpose of this article is...
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FEM simulation of laminate failure in the three point bending
PublicationThe paper presents a FEM simulation of failure of laminate subjected to the three point bending. The numeri-cal model is based on the equivalent single layer approach with 6-paramater non-linear shell theory kinematics. It is implemented in the non-commercial FEM code. The failure initiation is detected with the use of Tsai-Wu criterion. After the failure onset the progressive failure process is modelled through the appropriate...
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River flow simulation based on the HEC-RAS system
PublicationThis work considers the problem of river floods, and presents a computer solution that can be used to predict such a threat. The basic tool, called Hydrologic Engineering Centers for River Analysis System (HEC-RAS), and created by the US Army Corps of Engineering, is well developed; and the models created in the system HEC-RAS are quite realistic. For the purpose of solving practical national flood problems, simplified static and...
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River Flow Simulation Based on the HEC-RAS System
PublicationThis work considers the problem of river floods, and presents a computer solution that can be used to predict such a threat. The basic tool, called Hydrologic Engineering Centers for River Analysis System (HEC-RAS), and created by the US Army Corps of Engineering, is well developed; and the models created in the system HEC-RAS are quite realistic. For the purpose of solving practical national flood problems, simplified static and...
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Multi-objective optimization of expensive electromagnetic simulation models
PublicationVast majority of practical engineering design problems require simultaneous handling of several criteria. For the sake of simplicity and through a priori preference articulation one can turn many design tasks into single-objective problems that can be handled using conventional numerical optimization routines. However, in some situations, acquiring comprehensive knowledge about the system at hand, in particular, about possible...
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Simulation of the profile wear of the tool in double wheel lapping
PublicationW pracy przedstawiono model zużycia narzędzia w docieraniu dwutarczowym. Wyprowadzono równania opisujące kontakt przedmiotu z narzędziem. Przedstawiono wyniki analiz symulacyjnych dla różnych parametrów kinematycznych - dla układu współbieżnego i przeciwbieżnego.
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Multi-agent large-scale parallel crowd simulation
PublicationThis paper presents design, implementation and performance results of a new modular, parallel, agent-based and large scale crowd simulation environment. A parallel application, implemented with C and MPI, was implemented and run in this parallel environment for simulation and visualization of an evacuation scenario at Gdansk University of Technology, Poland and further in the area of districts of Gdansk. The application uses a...
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Real-time simulation in non real-time environment
PublicationSimulation in real-time is a very useful tool because of didactical and practical benefits. Very important benefit of real-time simulation is a fact that operator’s decision can be taken into account in the same time scale as the real system would work. This enables construction of simulators, and opportunity to test control algorithms in Hardware in The Loop scheme using target industrial equipment. Professional real-time environments...
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Simulation model of IMS/NGN call processing performance
PublicationIn current telecommunications it is assumed that demands of the information society for quickly delivered services will be satisfied by the Next Generation Network (NGN) architecture, which includes IP Multimedia Subsystem (IMS) elements. To guarantee Quality of Service (QoS), proper design and dimensioning of NGN is absolutely necessary, for which appropriate models have to be proposed. As the NGN architecture is very complicated,...
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Analysis of Agricultural and Engineering Systems using Simulation Decomposition
PublicationThis paper focuses on the analysis of agricultural and engineering processes using simulation decomposition (SD). SD is a technique that utilizes Monte Carlo simulations and distribution decomposition to visually evaluate the source and the outcome of different portions of data. Here, SD is applied to three distinct processes: a model problem, a nondestructive evaluation testing system, and an agricultural food-water energy system....
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INFOGEST static in vitro simulation of gastrointestinal food digestion
PublicationDeveloping a mechanistic understanding of the impact of food structure and composition on human health has increasingly involved simulating digestion in the upper gastrointestinal tract. These simulations have used a wide range of different conditions that often have very little physiological relevance, and this impedes the meaningful comparison of results. The standardized protocol presented here is based on an international consensus...
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Numerical simulations of a triaxial test in granular bodies using discrete particle simulations with contact moments
PublicationW artykule przedstawiono wyniki symulacji badania trójosiowego dla materiałów granulowanych. Obliczenia wykonano przy zastosowaniu metody DEM. Pokazano wpływ momentów kontaktowych na wytrzymałość próbki. Zbadano wpływ parametrów mikroskopowych.
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Exploring the Phenomenon of the Additive Colour Process While Using a Computer Programme by 7–8-Year-Old Students
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Computer-Aided System for Layout of Fire Hydrants on Boards Designed Vessel Using the Particle Swarm Optimization Algorithm
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Computer-aided analysis of signals from a low-coherence Fabry-Perot interferometer used for measurements of biological samples
PublicationThe aim of the study was to develop an automated computer-aided system for analysis of spectrograms obtained from measurements of biological samples performed with a low-coherence Fabry-Pérot interferometer. Information necessary to determine dispersion characteristics of measured materials can be calculated from the positions of the maxima and minima that are present in their spectra. The main challenge faced during the development...
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Towards Computer-Aided Graphene Covered TiO2-Cu/(CuxOy) Composite Design for the Purpose of Photoinduced Hydrogen Evolution
PublicationIn search a hydrogen source, we synthesized TiO2-Cu-graphene composite photocatalyst for hydrogen evolution. The catalyst is a new and unique material as it consists of copper-decorated TiO2 particles covered tightly in graphene and obtained in a fluidized bed reactor. Both, reduction of copper from Cu(CH3COO) at the surface of TiO2 particles and covering of TiO2-Cu in graphene thin layer by Chemical Vapour Deposition (CVD) were...
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Parallel computations in the volunteer based Comcute system
PublicationThe paper presents Comcute which is a novel multi-level implemen- tation of the volunteer based computing paradigm. Comcute was designed to let users donate the computing power of their PCs in a simplified manner, requiring only pointing their web browser at a specific web address and clicking a mouse. The server side appoints several servers to be in charge of execution of particular tasks. Thanks to that the system can survive...
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Volunteer Computing System Comcute with Smart Scheduler
PublicationIn this paper, a volunteer grid called Comcute is studied. Moreover, the harmony search scheduler is proposed. This scheduler has been designed for efficient using some resources of volunteer grid. The harmony search scheduler optimizes both a workload of a bottleneck computer and the cost of grid. Finally, some experiment outcomes have been discussed.
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Foundations of Grid Processing Architecture for the Comcute System
PublicationFundamental system algorithms and structures implemented in the Comcute system are described and analysed in detail. Layered architecture of the system model is highlighted. System tasks of the layers are elaborated, presented and described. Operational details of communication interfaces among layers are worked out and examined. The focus is put onto implemented system components with regard to their operability and efficiency....
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Enhancing Renal Tumor Detection: Leveraging Artificial Neural Networks in Computed Tomography Analysis
PublicationRenal cell carcinoma is one of the most common cancers in Europe, with a total incidence rate of 18.4 cases per 100 000 population. There is currently significant overdiagnosis (11% to 30.9%) at times of planned surgery based on radiological studies. The purpose of this study was to create an artificial neural network (ANN) solution based on computed tomography (CT) images as an additional tool to improve the differentiation of...
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An Approach to Bass Enhancement in Portable Computers Employing Smart Virtual Bass Synthesis Algorithms
PublicationThe aim of this paper is to present a novel approach to the Virtual Bass Synthesis (VBS) algorithms applied to portable computers. The developed algorithms are related to intelligent, rule-based setting of synthesis parameters according to music genre of an audio excerpt and to the type of a portable device in use. To find optimum synthesis parameters of the VBS algorithms, subjective listening tests based on a parametric procedure...
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Computed vibrational excitation ofCF4by low-energy electrons and positrons: Comparing calculations and experiments
PublicationQuantum calculations for the excitation of the asymmetric modes of the CF4 target gas, ν3 and ν4, by impact of low-energy electrons and positrons are carried out in the energy range around 1 eV and are compared with recent experimental findings. The similarities and differences between the two types of projectiles, and the two different modes, are analyzed and discussed vis à vis the present accord with the experimental results.
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Imaging of Increasing Damage in Steel Plates Using Lamb Waves and Ultrasound Computed Tomography
PublicationThis paper concerns inspection of steel plates, with particular emphasis on the assessment of in-creasing damage. Non-destructive tests were performed on four plates, one of which was un-damaged, while the remaining three had a defects in the form of circular holes with a diameter of 2, 5, and 10 cm. Guided Lamb waves were used in the research, and the image reconstruction was performed using ultrasound computed tomography. The...