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Wyniki wyszukiwania dla: model samouczacy
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Time-frequency characteristics of chemical oscillations. Experimental and model studies.
PublikacjaW publikacji zaprezentowano wykorzystanie czasowo-częstotliwościowych metod analizy sygnałów niestacjonarnych do badania reakcji Biełousowa-Żabotyńskiego. Zastosowanie krótkoczasowej transformaty Fouriera (STFT) pozwoliło na uzyskanie spektrogramów przedstawiających zmiany energii i częstotliwości oscylacji w trakcie trwania reakcji chemicznej. Przedyskutowano podobieństwa i różnice pomiędzy spektrogramami wygenerowanych dla eksperymentalnych...
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Direct reduction of pellets through hydrogen: Experimental and model behaviour
PublikacjaThis paper presents the hydrogen reduction behaviour of industrial pellets designed for the efficient hydrogen based direct reduction. The pellets were provided with very low non ferrous oxides percentage (0.52 of basicity index) and with the absence on TiO2 oxides. The pellets measured diameters in the range 1.14–1.72 cm and were characterized in terms of porosity, pores size, tortuosity and compression strength. The pellets were...
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Static and dynamic concrete calculations: Breakable aggregates in DEM model
PublikacjaThe paper deals with the calculations of a 3-point bending beam under static and dynamic loads. The real microstructure was obtained from laboratory tests using micro-tomography images. The quasi-static results were compared directly with experimental data at both macro and micro levels. Subsequently, higher strain rates were applied to investigate dynamic effects. The study focused on the influence of dynamic loading on the macroscopic...
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Towards the Development of a Risk Model for Unmanned Vessels Design and Operations
PublikacjaAn unmanned merchant vessel seems to be escaping from the stage of idea exploration. Once the concept proofs its safety, it may become a part of maritime reality. Although the safety aspect of such a ship has been addressed by a handful of scholars, the problem remains open. This is mainly due to lack of knowledge regarding actual operational circumstances and design of unmanned ships, which are yet to be developed. In the...
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Global Surrogate Modeling by Neural Network-Based Model Uncertainty
PublikacjaThis work proposes a novel adaptive global surrogate modeling algorithm which uses two neural networks, one for prediction and the other for the model uncertainty. Specifically, the algorithm proceeds in cycles and adaptively enhances the neural network-based surrogate model by selecting the next sampling points guided by an auxiliary neural network approximation of the spatial error. The proposed algorithm is tested numerically...
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Ship Dynamic Positioning Based on Nonlinear Model Predictive Control
PublikacjaThe presented work explores the simulation test results of using nonlinear model predictive control algorithm for ship dynamic positioning. In the optimization task, a goal function with a penalty was proposed with a variable prediction step. The results of the proposed control algorithm were compared with backstepping and PID. The effect of estimation accuracy on the control quality with the implemented algorithms was investigated....
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System Loss Model for Body Area Networks in Room Scenarios
PublikacjaThis paper presents an analysis of system loss in Body Area Networks for room scenarios, based on a wideband measurement campaign at 5.8 GHz. The measurements were performed with a fixed antenna transmitting vertically and horizontally polarised signals, while the user wears dualpolarised antennas. The average system losses in co- and crosspolarised channels are 41.4 and 42.6 dB for vertically polarised transmitted signals and...
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Sustainable Waste Management for Implementation of a Circular Economy Model in a Port
PublikacjaThe manuscript presents the management of waste from marine vessels and cargo handling companies in a selected European Union port. The main objective of the paper is to analyse and evaluate the existing waste management model in the port of Szczecin in the context of circular economy. The expert research carried out is aimed, inter alia, at identifying which of the solutions currently in use need to be improved from an environmental...
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Activity-based payments: alternative (anonymous) online payment model
PublikacjaElectronic payments are the cornerstone of web-based commerce. A steady decrease in cash usage has been observed, while various digital payment technologies are taking over. They process sensitive personal information raising concerns about its potentially illicit usage. Several payment models that confront this challenge have been proposed. They offer varying levels of anonymity and readiness for adoption. The aim of this study...
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Impulsive lubrication of hip joint for hypo-elastic cartilage model
PublikacjaPraca rozwiązuje problem smarowania stawu biodrowego człowieka w warunkach niestacjonarnych z uwzględnieniem hypo-sprężystych (pod-sprężystych) właściwości odkształcalnej szkieletu chrząstki stawowej. Prezentowane są rozkłady wartości ciśnienia hydrodynamicznego oraz zmienne w czasie rozkłady wartości sił nośnych.
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Pasmo Gdańsk-Kartuzy a teoretyczny model urbanizacji funkcjonalno-przestrzennej
PublikacjaOpracowanie przypomina koncepcje tzw. "korytarzy osiedleńczych" tworzonych przez pasma zurbanizowane, w skład których wchodziły wyodrębnione strukturalne jednostki osadnicze. Pasma te były obsługiwane przez wiązki infrastruktury technicznej a dostępność do poszczególnych jednostek i ich wielkości wynikały z warunków i możliwości technicznych środków komunikacji masowej, oraz możliwości fizycznych człowieka określanych parametrami...
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A quasi-2D small-signal MOSFET model - main results
PublikacjaDynamic properties of the MOS transistor under small-signal excitation are determined by kinetic parameters of the carriers injected into the channel, i.e., the low-field mobility, velocity saturation, mobility at the quiescent-point (Q-point), longitudinal electric field in the channel, by dynamic properties of the channel, as well as by an electrical coupling between the perturbed carrier concentration in the channel and the...
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Estimation of blood pressure parameters using ex-Gaussian model
PublikacjaThe paper presents an example of model-based estimation of blood pressure parameters (onset, systolic and diastolic pressure) from continuous measurements. First, the signal was low pass filtered and its quality was estimated. Good quality periods were divided into beats using an electrocardiogram. Next, the beginning of each beat of the blood pressure signal was approximated basing on the function created from the sum of two independent...
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Model of the double-rotor induction motor in terms of electromagnetic differential
PublikacjaThe paper presents a concept, a construction, a circuit model and experimental results of the double-rotor induction motor. This type of a motor is to be implemented in the concept of the electromagnetic differential. At the same time it should fulfill the function of differential mechanism and the vehicle drive. One of the motor shafts is coupled to the direction changing mechanical transmission. The windings of the external rotor...
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An Empirical Model for the Polarisation Characteristics of Indoor Off-Body Channels
PublikacjaThis paper presents an analysis of the polarisation characteristics for the channel in dynamic off-body communications, and an empirical channel model, based on measurements performed at 2.45 GHz in an office environment. Body presence and propagation conditions have a strong influence on signal depolarisation. The model assumes three components for the total path loss: mean path loss, represented by a log-distance function with...
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A Quasi-2D MOSFET Model — 2D-to-Quasi-2D Transformation
PublikacjaA quasi-two-dimensional (quasi-2D) representation of the MOSFET channel is proposed in this work. The representation lays the foundations for a quasi 2D MOSFET model. The quasi 2D model is a result of a 2D into quasi 2D transformation. The basis for the transformation are an analysis of a current density vector field and such phenomena as Gradual Channel Detachment Effect (GCDE), Channel Thickness Modulation Effect (CTME), and...
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A Model-Driven Solution for Development of Multimedia Stream Processing Applications
PublikacjaThis paper presents results of action research related to model-driven solutions in the area of multimedia stream processing. The practical problem to be solved was the need to support application developers who make their multimedia stream processing applications in a supercomputer environment. The solution consists of a domain-specific visual language for composing complex services from simple services called Multimedia Stream...
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A quasi-2D small-signal MOSFET model - main results
PublikacjaMain results stemming from a new quasi 2D non-quasi-static small-signal four-terminal model of the MOSFET are presented in this work. The model is experimentally verified up to 30 GHz.
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A calibration model for gas sensor array in varying environmental conditions
PublikacjaAbstract: Gas-analyzing systems based on gas sensors, commonly referred to as electronic noses, are the systems which enable the recognition of volatile compounds in their working environment and provide the on-line results of analysis. The most commonly used type of sensors in such systems is semiconductor gas sensors. They are considered to be the most reliable in the long-term applications (more than 1 year), however,...
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Peculiarities associated with testing polyetheretherketone (PEEK) in a model rolling contact
PublikacjaPolyetheretherketone (PEEK) was investigated using a modified version of the four-ball tester in which the upper forth ball was replaced by a cone in such a way that kinematics of the four-ball configuration were fully preserved. Rotation of the cone enforced orbiting and rolling of the ceramic balls around the polymer cup. The results produced some unexpected peculiarities in the wear of ceramic balls which, in principle, should...
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Model dynamicznego balastowania małego morskiego obiektu typu stealth
PublikacjaW artykule przedstawiono podstawowe problemy związane z modelowaniem głównych cech decydujących o trudno-wykrywalności małego obiektu na etapie projektu koncepcyjnego. Metoda badawcza oparta jest na ocenie zachowania się obiektu i ocenie ryzyka wypadku. W artykule skupiono się głównie na przedstawieniu modelu matematycznego opisującego model dynamicznego balastowania małego morskiego obiektu typu stealth. Przedstawione w artykule...
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A Human Behaviour Model Agent for Testing of Voluntary Computing Systems
PublikacjaPaper presents a design and performance of a voluntary-based distributed computing system testing agent, implementing a human behaviour model. The agent, nicknamed iRobot, was designed and implemented to enable controlled, large scale testing of core algorithms of Comcute - a new voluntary distributed computing platform complementary to BOINC. The main agent design goals were: emulation of human behaviour when browsing web pages,...
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A calibration model for gas sensor array in varying environmental conditions
PublikacjaAbstract: Gas-analyzing systems based on gas sensors, commonly referred to as electronic noses, are the systems which enable the recognition of volatile compounds in their working environment and provide the on-line results of analysis. The most commonly used type of sensors in such systems is semiconductor gas sensors. They are considered to be the most reliable in the long-term applications (more than 1 year), however,...
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Model spirali płacowo-cenowej w warunkach gospodarki polskiej
PublikacjaCelem artykułu było przedstawienie koncepcji teoretycznej modelu spirali płacowo-cenowej oraz poddanie jej empirycznej weryfikacji. U podstaw modelu spirali inflacyjnej leży zwrotna zależność pomiędzy poziomem płac a poziomem cen w gospodarce narodowej. W części teoretycznej artykułu w pierwszej kolejności przedstawiono założenia do funkcjonowania przedsiębiorstw na rynku pracy w warunkach konkurencji monopsonistycznej, uznając...
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Delay induced oscillations in gene expression of Hes1 protein model
PublikacjaW pracy został omówiony model produkcji białka Hes1. Stężenie Hes1 jest kontrolowane przez ujemne sprzężenie zwrotne wbudowane w białko i jego mRNA. Przeprowadzona analiza potwierdziła znane wyniki numeryczne, że oscylacje wywołane są przez opóźnienie. Pokazaliśmy również, że jeśli współczynnik Hilla jest większy niż 1, to istnieje krytyczna wartość opóźnienia, dla której ma miejsce bifurkacja Hopfa i pojawiają się rozwiązania...
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Survival time prognosis under a Markov model of cancer development
PublikacjaIn this study we look at a breast cancer data set of women from Pomerania region collected in year 1987-1992 in the Medical University of Gdańsk. We analyze the clinical risk factors in conjunction with Markov model of cancer development. We evaluate Artificial Neural Network (ANN) survival time prediction via a simulation study.
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1D Model Callibration on the Basis on 3D calculations for Tesla Turbine
PublikacjaThe paper presents the system of equations for axisymmetriclaminar flow, after averaging, through the width of interdisk slit ofTesla turbine. Coefficients were introduced, as a result ofaveraging, that improve the efficiency of 1D model. The minimalnumber of such coefficients was determined. The 1D modelmakes it possible to attain analytical solutions to an accuracylimited by these coefficients. Calibration of 1D model depends...
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Frequency-dependent coupling model for microwave band-pass filter
PublikacjaThe goal of this work was to create a circuit model which represents frequency-dependent coupling between microwave resonators. Our models are designed for in-line filters. The frequency-dependent coupling enables one to realize a transmission zero which is not possible in classical approach with frequency independent inverters. In addition, the proposed model allows us to observe out-of-band behavior, e.g. spurious resonance....
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Modified linear viscoelastic model of earthquake-induced structural pounding
PublikacjaIn recent times, earthquake-induced structural pounding has been intensively studied through the use of different impact force models. The numerical results obtained from the previous studies indicate that the linear viscoelastic model is relatively simple and accurate in modeling pounding-involved behavior of structures during earthquakes. The only shortcoming of the model is a negative value of the pounding force occurring just...
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An evaluation of effectiveness of fuzzy logic model in predicting the business bankruptcy
PublikacjaW artykule sprawdzono skuteczność pojedynczego modelu logiki rozmytej w prognozowaniu ryzyka upadłości przedsiębiorstw w Polsce. W badaniach wykorzystano wartości 14 wskaźników finansowych oraz ich dynamikę zmiany między pierwszym a drugim, drugim a trzecim oraz trzecim a czwartym rokiem objętymi analizą. We wnioskach omówiono różnicę w skutecznościach modelu uzyskanego na wartościach statycznych oraz dynamicznych wskaźników finansowych....
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Model instalacji napowietrzającej dla celów sterowania - studium przypadku
PublikacjaBiologiczne oczyszczanie ścieków stanowi podstawową grupę procesów w oczyszczalni ścieków. Jednym z nich jest napowietrzanie ścieków realizowane z wykorzystaniem instalacji napowietrzającej. Powszechnie uważa się go za jeden z najważniejszych i najdroższych procesów w oczyszczalni ścieków. Model procesu jest potrzebny do szczegółowej jego analizy, zbadania możliwości modyfikacji istniejących lub zastosowania innych metod sterowania....
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Wysokopoziomowy model projektowania wskaźników KPI systemów inteligentnych miast
PublikacjaCelem pracy jest prezentacja etapów budowy wysokopoziomowych modeli projektowania wskaźników KPI (WPMPW) systemów inteligentnych miast. Dotychczasowy rozwój, badanie procesów miast i przyporządkowanie im miar może być kontrolowane za pomocą wskaźników KPI. Autorzy pracy w trakcie procesów projektowania zwrócili uwagę na ograniczoną użyteczność tak projektowanych wskaźników dla przedstawicieli miast. Stąd też zaproponowali koncepcję...
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Trigger-based Model to Assess the Readiness of IT Organizations to Agile Transformation
PublikacjaThe process of change the method of project management from waterfall to agile is called “agile transformation” (AT). The decision to agile transformation is undertaken based on many different factors. Many companies decide to abandon classic, waterfall methodology for agile without prior analysis. This approach makes the processes of agile transformation is hard to control and frequently the implementation of agile fails. The...
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Data Model Development for Security Information Sharing in Smart Grids
PublikacjaThe smart grid raises new security concerns which require novel solutions. It is commonly agreed that to protect the grid, the effective collaboration and information sharing between the relevant stakeholders is prerequisite. Developing a security information sharing platform for the smart grid is a new research direction which poses several challenges related to the highly distributed and heterogeneous character of the grid. In...
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Representation of magnetic hysteresis in a circuit model of a single-phase transformer
PublikacjaThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. The set of loop differential equations was developed for K-th winding transformer model where the flux linkages of each winding includes a flux common Φ to all windings as function of magneto motive force Θ of all windings. The first purpose of this paper is to determine a hysteresis nonlinearity involved...
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Static Model of Steam/Water Cycle for Thermal and Economic Analysis
PublikacjaThe thermodynamic efficiency of typical conventional and nuclear power plants is insufficient. A large amount of the generated heat is removed to the environment and regarded as a waste. A solution which is commonly used to increase the efficiency and profitability of the existing and planned power plants refers to cogeneration of heat and power. To prepare sophisticated thermodynamic and economic analyses, a precise static model...
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NUMERYCZNY MODEL OBLICZENIOWY OBIEGU TURBINY KLASY 300 MW
PublikacjaNiniejszy artykuł stanowi opis modelu obiegu cieplnego turbiny o mocy 360MW, utworzonego w preprocesorze numerycznego programu obliczeniowego onazwie DIAGAR. Zadaniem opisywanego modelu jest odtwarzanie zjawisk fizycznych zachodzących w poszczególnych urządzeniach składowych obiegu, zarówno podczas poprawnej (sprawnej) pracy bloku energetycznego, jak i w przypadku pojawienia się niesprawności. Utworzony...
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MACRO MODEL OF SEAT BELT USE BY CAR DRIVERS AND PASSENGERS
PublikacjaThe article presents some problems of seat belt use by car drivers and passengers. It looks in particular at seat belt use and effectiveness in selected countries. Next, factors of seat belt use are presented and methodology of model development. A macro model of seat belt use is presented based on data from around fifty countries from different continents.
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Wirtualny model zbiorników z wodą w sterowniku PLC
PublikacjaModele obiektów rzeczywistych otrzymuje się na różnorodne sposoby i wykorzystuje w różnorodnych celach. Do badania obiektów automatyki stosuje się najczęściej programy komputerowe, np.: Matlab-Simulink, Scilab, GNU Octave, itp. Można również stosować pamięć operacyjną sterowników [1, 2]. W referacie przedstawiono opis wirtualnego modelu dwóch połączonych zbiorników z wodą w sterowniku PLC. Proste przekształcenia matematyczne pozwalają...
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A simple model for automated negotiations over collaboration agreements in ebXML
PublikacjaPoważnym ograniczeniem w upowszechnianiu standardu ebXML(elektronicznego obiegu dokumentów)jest możliwość występowania konfliktu pomiędzy partnerami transakcji. W artykule zaproponowano prosty mechanizm umożliwiający rozstrzyganie takich konfliktów w drodze automatycznie realizowanych negocjacji, którego wdrożenie pozwoli znacznie rozszerzyć zakres stosowania standardu ebXML.
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Conception of interactive information and decision support system - model and evaluation
PublikacjaThis article presents conception of interactive information and decision support system for urban and industrial air quality management. The emphasis of the project is on real-time analysis and multi-media information, and support of distributed and mobile clients through the Internet.
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Model of heat transfer in the stagnation point of rapidly evaporating microjet
PublikacjaThe paper presents investigation in the single water microjet surface cooling producing evaporating film. Reported tests were conducted under steady state conditions. It was proved that the phenomenon is similar to that of pool boiling. Results of experiments were compared with predictions by the model showing a good consistency.
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LABORATORYJNY MODEL ODBIORNIKA DUŻEJ MOCY. KONCEPCJA, WYKONANIE, EKSPERYMENTY
PublikacjaW referacie przedstawiono koncepcję oraz sposób realizacji laboratoryjnego modelu odbioru o mocy 150 kVA. Odbiornik zaprojektowano w taki sposób aby umożliwić emulację zmienności mocy dowolnego odbiorcy, jak również pracę transformatora zasilającego takiego odbiorcę. W referacie zaprezentowano też przykładowe wyniki prób eksperymentalnych potwierdzające słuszność przyjętej koncepcji sterowania.
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Model Order Reduction for Problems With Dispersive Surface Boundary Conditions
PublikacjaThis letter proposes a new scheme for reduced-order finite-element modeling of electromagnetic structures with nonlinear, dispersive surface boundary conditions, which optimally exploits the numerically stable and efficient MOR framework for second-order systems provided by SAPOR method. The presented results of numerical experiments for an example of a waveguide filter demonstrate the superior accuracy of the resulting reduced models...
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Experience-Driven Model of Decision-Making Processes in Project Teams
PublikacjaThis article presents a model of decision-making processes in project teams. Project teams constitute a specific type of organization appointed to implement a project. Decisions made by project teams result from the methods of project management and best management practices. The authors have undertaken the task of formalizing these processes using the classical method of constructing decision trees. It has been established that...
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Decisional-DNA Based Smart Production Performance Analysis Model
Publikacjan order to allocate resources effectively according to the production plan and to reduce disturbances, a framework for smart production performance analysis is proposed in this article. Decisional DNA based knowledge models of engineering objects, processes and factory are developed within the proposed framework. These models are the virtual representation of manufacturing resources, and with help of Internet of Things, are capable...
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On the Equations of the Surface Elasticity Model Based on the Theory of Polymeric Brushes
PublikacjaMotivating by theory of polymers, in particular, by the models of polymeric brushes we present here the homogenized (continual) two-dimensional (2D) model of surface elasticity. A polymeric brush consists of an system of almost aligned rigid polymeric chains. The interaction between chain links are described through Stockmayer potential, which take into account also dipole-dipole interactions. The presented 2D model can be treated...
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A material model of asphalt mixtures based on Monte Carlo simulations
PublikacjaThe paper aims to numerically reflect mineral-asphalt mixture structure by a standard FEM software. Laboratory test results are presented due to bending tests of circular notched elements. The result scatter is relatively high. An attempt was made to form a random aggregate distribution in order to obtain various results corresponding to laboratory tests. The material structure calibration, its homogenization and finite element...
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Importance of model tests in design and operation of watercraft for example CTO
PublikacjaShip Hydromechanics Division is a specialized research and development department of Ship Design and Research Centre conducting tests and research in the field of hydromechanics, connected with design and operation of ships and other floating structures, in scope of: predictions, numerical analyses, designs of - hull shape optimized with respect to the ship’s functions with the application of modern design tools, screw propellers...
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Positive Management of Universities: A Model of Motivation to Strive for Scientific Excellence
PublikacjaObjective: The aim of the article is to conceptualise a model of work motivation in the management of universities striving for scientific excellence. Research Design & Methods: The most relevant for our aim is the self-determina tion theory that is applied to the work and organisational domain. We used a nar rative literature review. Findings: The proposed model is derived from the self-determination theory. It includes three...