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Search results for: DISCRETE-EVENT SIMULATION
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Szkoła letnia na WETI
EventsKatedra Algorytmów i Modelowania Systemów WETI organizuje szkołę letnią pt.: "Gdansk Summer School of Advanced Science on Algorithms for Discrete Optimization" dla osób zainteresowanych algorytmiką i teorią grafów.
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Safety assessment of a concrete viaduct damaged by vehicle impact and an evaluation of the repair
PublicationDamage to lower parts of viaducts caused by impact from under-passing high vehicles is relatively frequent. One such incident, in which a viaduct was damaged by the impact from a truck with an improperly assembled hydraulic crane, is considered in this work. The analysis is based on a detailed object damage evaluation, 3D laser scanning, and numerical simulations. The aim of the study is to accurately model the vehicle impact into...
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A Nyquist filter of fractional delay
PublicationIn the paper a novel discrete-time FIR fractonal delay specjal filter is investigated. This is a Nyquist filter which, besides the traditional its attribute (interymbol interference (ISI) free property), has the ability to compensate for subsample transmission delay involved, for example, in multipath propagation channel. The performance of the filter is analysed and illustrated.
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New Concept of Numerical Ship Motion Modelling for Total Ship Operability Analysis by Integrating Ship and Environment Under One Overall System
PublicationThe paper presents a new concept of overall ship motion modelling for application to total ship operability. The delivered model is a multi-phase and includes both submerged part of ship’s hull and the surrounding water as a unique body. The Discrete Finite Element Method is applied. The model is successfully examined and illustrated for a selected AHTS.
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Modeling the impact of discretizing rotor angular position on computation of field-oriented current components in high speed electric drives
PublicationModern drives consist of alternating current electric motors, and the field-oriented control (FOC) of such motors enables fast, precise, and robust regulation of a drive's mechanical variables such as torque, speed, and position. The control algorithm, implemented in a microprocessor, requires feedback from motor currents, and the quality of this feedback is essential to a drive's control properties. Motor phase currents are sampled...
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Modelling hydraulic and capillary-driven two-phase fluid flow in unsaturated concretes at the meso-scale with a unique coupled DEM-CFD technique
PublicationThe goal of the research was to demonstrate the impact of thin porous interfacial transition zones (ITZs) between aggregates and cement matrix on fluid flow in unsaturated concrete caused by hydraulic/capillary pressure. To demonstrate this impact, a novel coupled approach to simulate the two-phase (water and moist air) flow of hydraulically and capillary-driven fluid in unsaturated concrete was developed. By merging the discrete...
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On the Structure of Time in Computational Semantics of a Variable-Step Solver for Hybrid Behavior Analysis
PublicationHybrid dynamic systems combine continuous and discrete behavior. Often, computational approaches are employed to derive behaviors that approximate the analytic solution. An important part of this is the approximation of differential equation behavior by numerical integration. The accuracy and computational efficiency of the integration usually depend on the complexity of the method and its implicated approximation errors, especially...
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Periodic and chaotic dynamics in a map‐based neuron model
PublicationMap-based neuron models are an important tool in modeling neural dynamics and sometimes can be considered as an alternative to usually computationally costlier models based on continuous or hybrid dynamical systems. However, due to their discrete nature, rigorous mathematical analysis might be challenging. We study a discrete model of neuronal dynamics introduced by Chialvo in 1995. In particular, we show that its reduced one-dimensional...
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Analysis of compressive forces in CFGFT cylindrical pillars and their coatings using laboratory tests and metric spaces
PublicationThe article discusses compressive forces tests in composite-concrete pillars with the use of laboratory active experiment including the factors and properties of materials which have a significant impact on the test results and their repeatability. A polymer composite based on glass fiber reinforced resin with different fiber beam angles (20, 55 and 85) was used as a buffer/coat of the pole. Due to the problems with direct comparison...
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Frequency and time domain characteristics of digital control of electric vehicle in-wheel drives
PublicationIn-wheel electric drives are promising as actuators in active safety systems of electric and hybrid vehicles. This new function requires dedicated control algorithms, making it essential to deliver models that reflect better the wheel-torque control dynamics of electric drives. The timing of digital control events, whose importance is stressed in current research, still lacks an analytical description allowing for modeling its...
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Editorial, SI EATA2023
PublicationThe European Asphalt Technology Association (EATA) is an organisation of leading European engineers and scientists involved in the asphalt material research. Every two years, the EATA celebrates its international pavement conference, with the aim of disseminating the key advances in scientific knowledge related to asphalt materials and technologies, and to encourage the transfer and application of this knowledge worldwide. Since...
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Flock behavior and control
PublicationIn this paper we present the results of the Flock Behaviour and Control workshop cluster during “Shapes of Logic Conference 2015”. During the event, students got familiar with the techniques of both visual and sound real-time data processing. The second topic presented for students was behaviourbased approach of design process, mainly based on the mathematical rules set up by Craig Raynolds on the swarm behaviour. The aim of the...
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International Workshop on Modelling, Simulation, Verification and Validation of Enterprise Information Systems
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Active and Dynamic Graphical Code for Object Identification in Healthcare
PublicationA new approach for item marking using two dimensional discrete graphics markers. Proposed solution allow o change the code rapidly, upon request and in the case of thermal markers make the code invisible for unauthorized observers. Connecting the proposed codes with wearable multmedial platform such as eGlasses can create new possibilities in human-environment interaction.
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Application of non-classical operational calculus to indicate hazards in numerical solutions of engineering problems
PublicationThe article addresses the application of non- classical operational calculus to approximative solutions of engineering problems. The engineering-sound examples show that a continuous–discrete problem transformation from differential unequivocal problem to a differential wildcard problem, triggering a change in solution quality. A number of approximative methods are capable to alter both quantitative and qualitative...
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Ships Shore Service Optimization Using the Queueing Theory
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Non-regular, incomplete and singular dynamical systems: impasse points indynamical systems
PublicationRozważono nieregularne, niezupełne i osobliwe różniczkowe systemy dynamicznez zastosowaniem metod geometrii różniczkowej.
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Qualitative and quantitative mechanisms in managing IT projects in concur-rent engineering environment
PublicationW artykule przedstawiono wprowadzenie do twardych i miękkich moetod modelowania. Nastepnie wprowadzono czytelnika do obszaru inżynierii równoległej (współzadaniowej). Całość zaproponowano jakośrodowisko wspomagania decyzji w procesach zarządzania złożonymi międzynarodowymi projektami badawczymi w obszaru Information Technology.
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I-lossless factorisations for robust H-inf-control in delta-domain
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Robust pole placement in delta domain for SISO plans
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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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Robust design in delta domain for SISO plants: PI and PID controllers
PublicationW pracy przedstawiono zunifikowaną metodę numerycznie odpornej syntezy sterowników (regulatorów) działających w dyskretnym czasie w układach sterowania skalarnymi obiektami czasu ciągłego. Wykorzystano dyskretnoczasowe modele takich obiektów, oparte na tak zwanym operatorze delta, charakteryzującym się korzystnymi odpornościowymi cechami w przypadku stosowania dostatecznie małych wartości okresu próbkowania przetwarzanych sygnałów....
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Conceptual system development in a concurrent environment
PublicationW artykule omówiono możliwości wspomagania jednego z najważniejszych obszarów projektowania, a mianowicie projektowania koncepcyjnego. Rozważania te odniesiono do otoczenia inżynierii wspozadaniowej, co dodatkowo skomplikowano problemy decyzyjne podejmowane na tym etapie projektowania. Zaproponowano szereg elementów wspomagania projektowania koncepcyjnego ze szczególnym uwzględnieniem możliwości praktycznej implementacji takiego...
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Vehicle Suspension Design, W, TiL II st., sem. 03, letni 23/24 (PG_00062882)
e-Learning CoursesRole of the suspension. Suspension kinematics and compliances theoretical background and practical measuring schemes. Suspension design an overview of suspension design properties and review of current design philosophy. Review of typical designs. Current design trends. Practical implications. Case studies introduction to modelling and simulation software and discussion of practical case studies.
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Vehicle Suspension Design, W, MiBM II st., sem. 03, letni 23/24 (PG_00062882)
e-Learning CoursesRole of the suspension. Suspension kinematics and compliances theoretical background and practical measuring schemes. Suspension design an overview of suspension design properties and review of current design philosophy. Review of typical designs. Current design trends. Practical implications. Case studies introduction to modelling and simulation software and discussion of practical case studies.
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Simulations of Shear Zones and Cracks in Engineering Materials Using eXtended Finite Element Method
PublicationNumerical simulations of cracks and shear zones in quasi-brittle materials are presented. Extended Finite Element Method is used to describe both cracks and shear zones. In a description of tensile cracks, a Rankine criterion is assumed. A discrete Mohr-Coulomb law is adopted for simulations of shear zones. Results of simple numerical tests: unixial tension, bending and biaxial compression are demonstrated.
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The α-µ model of the multipath fading channel
Open Research DataThe dataset contains the results of simulations that are part of the research on modelling the multipath fading in the communication channel. The envelope of the α-µ fading process is generated using the Monte-Carlo simulation (MCS) in the LabVIEW programming environment.
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The Rayleigh model of the multipath fading channel
Open Research DataThe dataset contains the results of simulations that are part of the research on modelling the multipath fading in the communication channel. The Rayleigh fading envelope is generated using the Monte-Carlo simulation (MCS) in the LabVIEW programming environment.
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Automatic detection of abandoned luggage employing a dual camera system
PublicationA system for automatic detection of events using a system of fixed and PTZ (pan-tilt-zoom) cameras is described. Images from the fixed camera are analyzed by means of object detection and tracking. Event detection system uses a set of rules to analyze data on the tracked moving objects and to detect defined events. A PTZ camera is used to obtain a detailed view of a selected object. A procedure for conversion between the pixel...
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Public Perception of Intangible Benefits and Costs in the Valuation of Mega Sports Events: The Case of Euro 2012 in Poland
PublicationThis article estimates the intangible benefits and costs of Euro 2012 in Poland. Using the contingent valuation method (CVM), a study was conducted among residents of all four host regions of the event and one nonhost region. This provided the basis for determining the net intangible benefit arising from Poland’s hosting of the European football championships (Euro 2012), which was estimated at 5.3 billion PLN2012. The aggregate...
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Cartographic Representation of Route Reconstruction Results in Video Surveillance System
PublicationThe video streams available in a surveillance system distributed on the wide area may be accompanied by metadata are obtained as a result of video processing. Many algorithms applied to surveillance systems, e.g. event detection or object tracking, are strictly connected with localization of the object and reconstruction of its route. Drawing related information on a plan of a building or on a map of the city can facilitate the...
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Real-time simulator of agricultural biogas plant
PublicationThis article presents a real-time simulator of an agricultural biogas plant. The project contains biogas and biomass circuits simulation, as well as heating circuit simulation with a complete control system and visualization interface of the whole process. The software tool used to simulate the plant work is CFD (Computational Fluid Dynamics), which enables a user to create and test simulation objects based on fundamental physical...
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Short-Term Price Reaction to Filing for Bankruptcy and Restructuring Proceedings—The Case of Poland
PublicationThis study aims to check market reaction to filing for bankruptcy and restructuring proceedings and to verify the short-term effect of a price reversal in the Polish market in the years 2004–2019. The research was conducted by dividing the analysed companies according to the procedure (bankruptcy and restructuring) and market (the main market and the NewConnect market). The research methodology used in the study is the event analysis...
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Marine traffic risk modelling – an innovative approach and a case study
PublicationThis paper presents a model to analyse the risk of two common marine accidents: collision and grounding. Attention is focused on oil tankers since they pose the highest environmental risks. A case study in selected areas of the Gulf of Finland in ice-free conditions is presented. The model utilizes a formula for risk calculation that considers both the probability of an unwanted event and its consequences. The model can be decomposed...
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Paweł Rościszewski dr inż.
PeoplePaweł Rościszewski received his PhD in Computer Science at Gdańsk University of Technology in 2018 based on PhD thesis entitled: "Optimization of hybrid parallel application execution in heterogeneous high performance computing systems considering execution time and power consumption". Currently, he is an Assistant Professor at the Faculty of Electronics, Telecommunications and Informatics, Gdańsk University of Technology, Poland....
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Comments on “Closed Form Variable Fractional Time Delay Using FFT”
PublicationIn this letter drawbacks of the aforementioned paper are pointed out. The proposed approach is improved with minor modifications of the discrete frequency response. This allows for design of fractional delay filters which are close to optimal and can be efficiently implemented in the frequency domain using the sliding DFT based structure. Alternatively, the derived equivalent closed form formulae for offset windows can be used...
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A Stand for Measurement and Prediction of Scattering Properties of Diffusers
PublicationIn this paper we present a set of solutions which may be used for prototyping and simulation of acoustic scattering devices. A system proposed is capable of measuring sound field. Also a way to use an open source solution for simulation of scattering phenomena occurring in proximity of acoustic diffusers is shown. The result of our work are measurement procedure and a prototype of the simulation script based on FEniCS - an open source...
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Edge ranking and searching in partial orders
PublicationArtykuł jest poświęcony problemowi konstrukcji optymalnej (wymagającej minimalnej ilości porównań/zapytań) strategii wyszukiwania elementu w częściowym porządku. W pracy wskazano związki pomiędzy tym problemem oraz uporządkowanym kolorowaniem krawędzi grafów, co implikuje liniowy algorytm dla częściowych porządków o strukturze drzewa. Pokazano również, że znalezienie optymalnej strategii jest problemem obliczeniowo trudnym dla...
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Forwarding and optical indices of a graph
PublicationW pracy rozstrzygnięto dwa problemy dotyczące komunikacji wszyscy-do-wszystkich w grafach. Stwierdzono, że dla wersji skierowanej problemu parametry ''pi'' (maksymalne obciążenie krawędzi) i ''w'' (parametr chromatyczny) nie muszą być w ogólności sobie równe. Dla wersji nieskierowanej problemu pokazano, że wyznaczenie wartości zarówno ''pi'', jak i ''w'', jest w ogólności problemem NP-trudnym.
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Total outer-connected domination numbers of trees
PublicationNiech G=(V,E) będzie grafem bez wierzchołków izolowanych. Zbiór wierzchołków D nazywamy zbiorem dominującym totalnym zewnętrznie spójnym jeżli każdy wierzchołek grafu ma sąsiada w D oraz podgraf indukowany przez V-D jest grafem spójnym. Moc najmniejszego zbioru D o takich własnościach nazywamy liczbą dominowania totalnego zewnątrznie spójnego. Praca m.in. zawiera dolne ograniczenie na liczbę dominowania totalnego zewnętrznie spójnego...
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A graph coloring approach to scheduling of multiprocessor tasks on dedicated machines with availability constraints
PublicationWe address a generalization of the classical 1- and 2-processor unit execution time scheduling problem on dedicated machines. In our chromatic model of scheduling machines have non-simultaneous availability times and tasks have arbitrary release times and due dates. Also, the versatility of our approach makes it possible to generalize all known classical criteria of optimality. Under these stipulations we show that the problem...
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A note on the strength and minimum color sum of bipartite graphs
PublicationSiłą grafu G nazywamy najmniejszą liczbę całkowitą s, taką że istniej pokolorowanie grafu G, o minimalnej sumie przy użyciu kolorów {1,...,s}. W pracy pokazano, że w grafach dwudzielnych stopnia D zachodzi oszacowanie s <= ceil(D/2) + 1. Z obserwacji tej wynika algorytm wielomianowy do obliczania siły i sumy chromatycznej w grafach dwudzielnych stopnia co najwyżej 4.
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Approximating the maximum 2- and 3-edge-colorable subgraph problems
PublicationDla ustalonej wartości parametru k>=2, problem maksymalnego podgrafu krawędziowo k-kolorowalnego polega na wskazaniu k rozłącznych skojarzeń w grafie prostym, a kryterium optymalizacji jest maksymalizacja całkowitej liczby użytych krawędzi. W pracy podano algorytmy 5/6- i 4/5-przybliżone odpowiednio dla przypadków k=2 i k=3, poprawiając wyniki znane z literatury.
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A station strategy to deter backoff attacks in IEEE 802.11 LANs
PublicationDla konstrukcji strategii zapobiegającej atakom na mechanizm odczekania w sieciach lokalnych IEEE 802.11 zastosowano wybór konfiguracji MAC sterowany przez liczniki etapów gry z losowymi wartościami początkowymi. Wykazano, że przy pewnych warunkach nałożonych na rozkady prawdopodobieństwa liczników standardowe ustawienia parametrów MAC stają się punktem doskonałej równowagi strategicznej.
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Easy and hard instances of arc ranking in directed graphs
PublicationArtykuł dotyczy uporządkowanego kolorowania łuków grafów skierowanych. Problem polega na takim przyporządkowaniu liczb łukom digrafu, aby każda skierowana ścieżka łącząca dwa łuki o tej samej liczbie (kolorze) zawierała łuk o kolorze wyższym. Praca podaje liniowy optymalny algorytm dla pewnego szczególnego przypadku, oraz zawiera dowód, iż problem ten jest obliczeniowo trudny dla 3-dzielnych acyklicznych digrafów i stałej liczby...
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The complexity of the T-coloring problem for graphs with small degree
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Some results concerning the complexity of restricted colorings of graphs
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Compact scheduling of zero–one time operations in multi-stage systems
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Open shop problem with zero-one time operations and integer release date/deadline intervals
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On the deficiency of bipartite graphs
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