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Search results for: modele ekonometryczne
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Calculation of self and mutual inductances of the switched reluctance machine mathematical model.
PublicationA mathematical model of the switched reluctance machine (SRM) in a drive system obtained using Lagrange's energy method and a method of calculation of self and mutual inductances of the SRM are presented in the paper. The self and mutual inductances are elements of Lagrange's function in generalised coordinates and have been calculated using the finite element method (FEM). Selected calculation results for the particular machine...
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Modelling of fracture process in brittle materials using a lattice model
PublicationW artykule przedstawiono wyniki obliczeń propagacji rys w elementach betonowych przy zastosowaniu modelu dyskretnego opartego na ruszcie belkowym. Obliczenia wykonano dla różnych problemów brzegowych. Dla redukcji kruchości w obszarze pokrytycznym przyjęto model nielokalny obliczenia odkształceń.
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Comparative modelling of shear localization in granular bodies using a discrete and continuum approach
PublicationW artykule przedstawiono pierwsze wyniki symulacji rys w betonie przy zastosowaniu metody elementów dyskretnych. W obliczeniach wykorzystano program YADE. W symulacjach wykorzystano kulki o różnych średnicach. Przyjęto dodatkowo działanie momentu symulującego szorstkość ziaren.
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Modelling of fracture process in concrete using a novel lattice model.
PublicationArtykuł omawia wyniki modelowania procesu zarysowania w elementach betonowych przy zastosowaniu dyskretnego modelu kratownicowego. Beton był modelowany na poziomie mezoskali z uwzględnieniem 3 faz: kruszywa, zaczynu cementowego i stref kontaktu. Obliczenia wykonano dla rozciągania i ścinania połączonego z rozciąganiem.
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Reliability model of two-shaft turbine combustion engine with heat regenerator
PublicationW artykule przedstawiono możliwość zastosowania teorii procesów semimarkowskich do opisu niezawodności turbinowego silnika spalinowego. Opracowano model niezawodnościowy w formie siedmiostanowego procesu semimarkowskiego, umożliwiający określenie prawdopodobieństw przebywania silnika w stanie zdatności oraz wyróżnionych stanach niezdatności.
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General Active-RC filter model for computer-aided design
PublicationW pracy przedstawiono ogólną topologię filtru aktywnego RC czasu ciągłego. Proponowany model umożliwia zunifikowaną analizę wszystkich możliwych realizacji układowych filtrów aktywnych RC jako szczególnych przypadków danej struktury ogólnej. Poprawność modelu teoretycznego została zweryfikowana poprzez symulacje w programie SPICE.
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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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Hydrodynamic model experiments with pod propulsors. Oceanic Eng. Intern.**2001 vol. 5 nr 2 s. 95-103, 15 rys. bibliogr. 6 poz. Hydrodynamiczne badania modelowe pędników azymutalnych.
PublicationPraca przedstawia badania modelowe trzech wariantów pędnika azymutalnego.Celem badań było zmierzenie charakterystyk hydrodynamicznych pędników w za-leżności od parametrów pracy oraz przeprowadzenie obserwacji kawitacji.
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Mobile application technology in levelling
PublicationThe topic of this article is the use of mobile application technology in geodetic measurements with an emphasis on levelling. Reference points were registered as data from levelling benchmarks, performed with a traditional dumpy level. The created application allowed the recording of measurements on location, sending them to a remote server for processing and preparing a report to be saved in a database. The project was to decrease...
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Quality Expectations of Mobile Subscribers
PublicationMobile systems, by nature, have finite resources. Radio spectrum is limited, expensive and shared between many users and services. Mobile broadband networks must support multiple applications of voice, video and data on a single IP-based infrastructure. These converged services each have unique traffic holding and quality requirements. A positive user experience must be obtained through efficient partitioning of the available wireless...
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Wireless and mobile networking (Foreword)
PublicationArtykuł zawiera omówienie prac z zakresu technologii sieci bezprzewodowych zamieszczonych na konferencji IFIP WMNC 2009.
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Modern server virtualization technologies
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The trends in modern car wash
PublicationPrzedstawiono przegląd różnych technik mycia samochodów ze szczególnym uwzględnieniem zużycia wody. Podano także nowoczesne wykorzystanie odwróconej osmozy z polimerowymi membranami do oczyszczania wody w zamkniętym obiegu myjni samochodowych.
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Cooperative mobile guards in grids
PublicationPraca dotyczy problemu strzeżenia dwuwymiarowych krat ortogonalnych, przy założeniu, że obszar widoczności strażnika obejmuje jedną ulicę oraz wszystkie ulice ją przecinające. Rozważano wariant straży słabo współpracujących, w którym dodatkowo każdy strażnik musi widzieć przynajmniej jednego innego strażnika. Podano dowód NP-trudności problemu optymalizacyjnego w przypadku ogólnym, algorytm dokładny o złożoności O(n log n) dla...
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Modern Methods of Software Development
PublicationSoftware development methods consist of such activities like analysis, planning, development, testing, deployment, maintenance and retirement. All of them can be divided into two main categories - traditional and agile. The objective of this paper is to review some of the most popular traditional, agile and open source development methods. Special attention was paid to the common stages of all methods - testing and maintenance.
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Internet Rzeczy - rozwiązania modelowe
PublicationW pracy omówiono problemy projektowania i realizacji sieci typu internet rzeczy (IoT). Scharakteryzowano podstawowe cechy systemów, które pozwalają na zakwalifikowanie ich do kategorii internet rzeczy. Przedstawiono wyniki testowania małej sieci typu „zrób to sam” zaprojektowanej i wykonanej w duchu idei internetu rzeczy. Oceniono, czy udało się osiągnąć nową jakość i synergiczny efekt wynikający z wykorzystania wielu źródeł danych...
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Psychotherapy assisted with mobile applications
Publication.
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Modern GFRP Composite Footbridges
PublicationApplication of GFRP composites in civil engineering is still not large but already noticeable. Advantages of this material, such as: low volume weight, relatively high stiffness and strength, well fatigue resistance, easiness in shaping, high material damping and high environmental resistance, make it attractive for bridge and in particular foot-bridge designers. It is estimated that nowadays in the world there are realized hundreds...
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Niedoskonałości Moodle - ocena subiektywna
PublicationW pracy dokonano specyfikacji wymagań systemu zdalnego nauczania odpowiadającego charakterowi polskich uczelni. Skonfrontowano te wymagania z możliwościami i cechami bardzo popularnego, szczególnie w Polsce, systemu Moodle.
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A MULTI-MASS DISCRETE MODEL OF TRIBOMETER FOR THE RESEARCH ON DYNAMIC FRICTION CHARACTERISTICS = Wielomasowy dyskretny model tribometru do symulacyjnych badań dynamicznych charakterystyk tarcia
PublicationW artykule przedstawiono metodykę opracowaną w celu redukcji modelu fizycznego tribometru z ciągłym rozkładem masy (bezwładności), sztywności podparcia oraz tłumienia do modelu dyskretnego. W modelu dyskretnym zastosowano zastępcze masy skupione i elementy sprężysto - tłumiące, których właściwości są dobrane w taki sposób, że charakterystyka drgań własnych tego modelu odpowiada charakterystyce rzeczywistego układu fizycznego. Dzięki...
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Static and dynamic concrete calculations: Breakable aggregates in DEM model
PublicationThe 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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Model of an Integration Bus of Data and Ontologies of Smart Cities Processes
PublicationThis paper presents a model of an integration bus used in the design of Smart Cities system architectures. The model of such a bus becomes necessary when designing high-level architectures, within which the silo processes of the organization should be seen from the perspective of its ontology. For such a bus to be used by any city, a generic solution was proposed which can be implemented as a whole or in part depending on the requirements...
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Wideband Model Order Reduction for Macromodels in Finite Element Method
PublicationAbstract: This paper presents a novel algorithm for accelerating 3D Finite Element Method simulations by introducing macromodels created in local model order reduction in the selected subdomains of the computational domain. It generates the projection basis for a compact system of equations associated with a separate subdomain. Due to non-linear frequency dependency in the Right Hand Side (RHS), the standard reduction methods do...
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Trigger-based Model to Assess the Readiness of IT Organizations to Agile Transformation
PublicationThe 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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High-Level Model for the Design of KPIs for Smart Cities Systems
PublicationThe main goal of the paper is to build a high-level model for the design of KPIs. Currently, the development and processes of cities have been checked by KPI indicators. The authors realized that there is a limited usability of KPIs for both the users and IT specialists who are preparing them. Another observation was that the process of the implementation of Smart Cities systems is very complicated. Due to this the concept of a...
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Estimation of blood pressure parameters using ex-Gaussian model
PublicationThe 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
PublicationThe 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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A Human Behaviour Model Agent for Testing of Voluntary Computing Systems
PublicationPaper 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
PublicationAbstract: 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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Data Model Development for Security Information Sharing in Smart Grids
PublicationThe 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
PublicationThe 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
PublicationThe 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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Model dynamiki sprężarki wirnikowej z regulowanymi łopatkami kierownicy
PublicationPrzedstawiono model dynamiki sprężarki wirnikowej turbiny gazowej współpracującej z siecią elektroenergetyczną. Model symuluje charakterystyki statyczne i dynamiczne sprężarki wirnikowej z regulowanym kątem nastawienia łopatek kierowniczych wlotowych. Za pomocą przedstawionego modelu dynamiki bloku elektroenergetycznego turbiny gazowej symulowano charakterystyki statyczne układu oraz charakterystyki dynamiczne. Odpowiedzi skokowe...
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Simple model of rain wind induced vibrations of stayed cables.
PublicationAnalizowano prosty, liniowy model drgań kabli mostów wantowych pod obciążeniem wiatrem i deszczem. Zakłada się, iż częstotliwość ruchu górnej kropli po powierzchni kabla i częstotliwość kabla są równe oraz iż amplituda ruchu kropli dla danej prędkości wiatru są stałe. Otrzymane rezultaty są porównane z istniejącymi w literaturze wynikami badań eksperymentalnych. Podaje się analityczne związki służące do oszacowania tłumienia...
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Efficient implementation of the Cauchy method for automated CAD-model construction.
PublicationW artykule przedstawiona została efektywna metoda konstrukcji wieloparametrycznych modeli układów mikrofalowych na podstawie wyników symulacji pełnofalowej. Algorytm wykorzystuje metodę najmniejszych kwadratów (TLS) do rozwiązania problemu interpolacyjnego i automatycznie dobiera rząd modelu.Przydatność i dokładność metody jest pokazana na przykładzie projektowania filtru z wykorzystaniem modeli trzech i pięciu zmiennych.
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Global Surrogate Modeling by Neural Network-Based Model Uncertainty
PublicationThis 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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Simplified Numerical Model for Transient Flow of Slurries at Low Concentration
PublicationRapid transients are particularly dangerous in industrial hydro-transport systems, where solid-liquid mixtures are transported via long pressure pipelines. A mathematical description of such flow is difficult due to the complexity of phenomena and difficulties in determining parameters. The main aim of the study was to examine the influence of the simplified mixture density and wave celerity description on satisfactory reproduction...
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Model systemu zarządzania usługami według metodologii design-thinking
PublicationW literaturze przedmiotu brakuje jednoznacznych wskazań odnośnie decyzji o wyborze najbardziej odpowiedniego modelu projektowania usług, szczególnie w kontekście różnych uwarunkowań dla poszczególnych sektorów rynku. Opracowany algorytm umożliwia samodzielne rozwiązanie problemu doboru modelu wewnątrz organizacji, bez konieczności zatrudniania zewnętrznego specjalisty. Algorytm skierowany jest do organizacji w fazie przygotowawczej...
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Ship Dynamic Positioning Based on Nonlinear Model Predictive Control
PublicationThe 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
PublicationThis 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
PublicationThe 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
PublicationElectronic 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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Direct reduction of pellets through hydrogen: Experimental and model behaviour
PublicationThis 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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A Simulation Model for Risk and Pricing Competition in the Retail Lending Market
PublicationWe propose a simulation model of the retail lending market with two types of agents: borrowers searching for low interest rates and lenders competing through risk-based pricing. We show that individual banks observe adverse selection, even if every lender applies the same pricing strategy and a credit scoring model of comparable discrimination power. Additionally, the model justifies the reverse-S shape of the response rate curve....
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Topological-numerical analysis of a two-dimensional discrete neuron model
PublicationWe conduct computer-assisted analysis of a two-dimensional model of a neuron introduced by Chialvo in 1995 [Chaos, Solitons Fractals 5, 461–479]. We apply the method of rigorous analysis of global dynamics based on a set-oriented topological approach, introduced by Arai et al. in 2009 [SIAM J. Appl. Dyn. Syst. 8, 757–789] and improved and expanded afterward. Additionally, we introduce a new algorithm to analyze the return times...
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Experimental Verification of the CFD Model of the Squeeze Film Lifting Effect
PublicationAbstract: The presented study shows the results of the research into the squeeze film levitation phenomena. The system introduced in the investigation is composed of a vibrating surface, air squeeze film, and the surface of the body freely suspended over the film. The use of the CFD (Computational Fluid Dynamics) model used in the system allows us to determine the steady state, periodic behavior of the air film (described by Navier–Stokes,...
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A Numerical Model Study on Grasse River Ice Control Structures
PublicationIce jams in the Grasse River have caused the erosion of capping material designed to prevent the resurfacing of the bed sediment in the PCB-contaminated area. Two in-stream ice-control structures are proposed to avoid the jam-induced erosion of the capping material. These two ice-control options are a pier-type ice-control structure and a reconstruction of a small hydropower dam upstream of the capping site. A numerical model study...
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Urban scene semantic segmentation using the U-Net model
PublicationVision-based semantic segmentation of complex urban street scenes is a very important function during autonomous driving (AD), which will become an important technology in industrialized countries in the near future. Today, advanced driver assistance systems (ADAS) improve traffic safety thanks to the application of solutions that enable detecting objects, recognising road signs, segmenting the road, etc. The basis for these functionalities...
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Extending the Shibboleth identity management model with a networked user profile
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Yeast as a Model to Characterize Anti-Aging Potential of Flavonoids (poster)
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