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Search results for: Huygens source
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Reduction of road traffic noise by source measures — present and future strategies
PublicationThe current trend worldwide is less focused on reducing road traffic noise. This is in strong contrast to the severe impact of traffic noise to the general health and quality of life. A more holistic and combined strategy is needed. Current international rules and regulations regarding vehicles and tyres are not sufficient to reduce traffic noise levels in an effective way. Calculations show that these regulations will only yield...
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Perfect thermal contact of hyperbolic conduction semispaces with an interfacial heat source
PublicationThe problem of thermal contact between two bodies with a heat source at their interface presents great scientific and practical interest. On the time scale of a nanosecond or shorter, heat propagation should be considered in the form of thermal waves of finite speeds. This study investigated the thermal behaviour of hyperbolic conduction semispaces in perfect thermal contact subjected to the action of an interfacial heat source....
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Optimal Components Design for Modified Z-Source Based IPT Approach
PublicationThis paper describes components estimation process for IPT approach based on Z-source network. Proposed model covers main parameters of the system and gives efficient way to evaluate optimal parameters for fixed switching frequency and distance.
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Step-Up DC/DC Converters With Cascaded Quasi-Z-Source Network
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Coastal erosion as a source of mercury into the marine environment along the Polish Baltic shore
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Plug-in to Eclipse environment for VHDL source code editor with advanced formatting of text
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Coastal cliff erosion as a source of toxic, essential and nonessential metals in the marine environment
PublicationDue to the rising environmental awareness, emissions and releases of pollutants, including metals, have been considerably reduced in the last decades. Therefore, the remobiliza-tion of natural and anthropogenic contaminants is gaining importance in their biogeochemical cycle. In the marine coastal zone, this process occurs during the erosion of a shore, especially the most vulnerable cliffs. The research was conducted in the...
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Trans-Z-source-like inverter with built-in DC current blocking capacitors
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Callus of American ginseng (Panax quinquefolius) as a source of ginsenosides – medicinal secondary metabolites
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Open-transistor fault diagnostics in voltage-source inverters by analyzing the load current
PublicationPrzedstawiono nową metodę detekcji i lokalizacji uszkodzeń polegających na braku przewodzenia tranzystorów w falownikach napięcia zasilających silniki indukcyjne. Metoda jest rozszerzeniem, opracowanej wcześniej, metody wykorzystującej znormalizowane składowe stałe prądów obciążenia. Znormalizowane wartości średnie prądów powiązano z dodatkowymi wskaźnikami diagnostycznymi, które zawierają informacje o czasie trwania nieprzewodzenia...
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A new open-source software developed for numerical simulations usingdiscrete modeling methods
PublicationThe purpose of this work is to present the development of an open-source software based on a discrete description of matter applied to study the behavior of geomaterials. This software uses Object Oriented Programming techniques, and its methodology design uses three different methods, which are the Discrete Element Method (DEM) [F. Donzé, S.A. Magnier, Formulation of a three-dimensional numerical model of brittle behavior, Geophys....
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Coastal erosion—a “new” land-based source of labile mercury to the marine environment
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Liquefaction of alder wood as the source of renewable and sustainable polyols for preparation of polyurethane resins
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Open-transistor fault diagnostics in voltage-source inverters by analyzing the load current
PublicationA novel method is presented for the detection andisolation of open-transistor faults in voltage-source invertersfeeding low-power AC motors. The method is based onmonitoring two diagnostic signals, one indicating sustained nearzerovalues of output current and thus permitting fault detection,the other permitting the isolation of the particular transistorwhich went faulty. The latter signal is the ratio of the averagephase current...
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Monetary Incentives Increase Metacognitive Confidence in Source Memory Performance in Patients With Schizophrenia
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Edible Flowers Extracts as a Source of Bioactive Compounds with Antioxidant Properties—In Vitro Studies
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Human amniotic-fluid-derived stem cells: a unique source for regenerative medicine
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Vortex cavitation as a source of high level acoustic pressure generated by ship propellers
PublicationPraca przedstawia wyniki badań teoretycznych i eksperymentalnych nad mechanizmami fizycznymi generowania wysokiego ciśnienia akustycznego przez kawitujące wiry wierzchołkowe powstające na śrubach okrętowych
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Using open source LMS Moodle in postgraduate studies at Gdansk University of Technology.
PublicationW artykule zaprezentowano doświadczenia Centrum Edukacji Niestacjonarnej Politechniki Gdańskiej na polu wdrażania systemów zarządzania nauczaniem na odległość w edukacji i korzystania z oprogramowania z otwartym kodem źródłowym (ang. open source) na przykładzie projektów Leonardo da Vinci EMDEL i V Ramowy CURE.
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Implementation of didactic simulation models in Open Source and SCORM compliant LMS systems.
PublicationModele symulacyjne są cenną pomocą w procesie dydaktycznym. Ich zastosowanie w systemach komputerowego wspomagania nauczania znacząco podnosi ich efektywność oraz pozwala na przeprowadzanie wirtualnych ćwiczeń laboratoryjnych (na przykład podczas nauczania na odległość). Niestety stosowane obecnie systemy LMS (Lerning Management System) nie są zadowalająco przystosowane do obsługi symulacyjnej zawartości dydaktycznej. W artykule...
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Analiza porównawcza systemów zarządzania nauczaniem opartych na licencji open source.
PublicationReferat zawiera przegląd najbardziej znanych systemów LMS opartych na licencji Open Source. Systemy przeanalizowano pod względem jakości interfejsu użytkownika, wsparcia dla standardów zdalnego nauczania oraz dostępności w języku polskim. Określono również technologie wykorzystywane do budowy analizowanych systemów.
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Analiza porównawcza systemów zarządzania nauczaniem opartych na licencji Open Source
PublicationReferat zawiera przegląd najbardziej znanych systemów LMS opartych na licencji Open Source. Systemy przeanalizowano pod względem jakości interfejsu użytkownika, wsparcia dla standardów zdalnego nauczania oraz dostępności w języku polskim. Określono również technologie wykorzystywane do budowy analizowanych systemów.
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Open source solution LMS for supporting e-learning/blended learning engineers
PublicationW artykule zaprezentowano darmowe systemy zarządzania kształceniem na odległość wspomagające e-learningowe/mieszane nauczanie inżynierów. Pierwszy system TeleCAD został opracowany w ramach projektu Leonardo da Vinci (1998-2001). System TeleCAD był propozycją w projekcie V Ramowy CURE (2003-2006). W roku 2003 dzięki projektowi Leonardo da Vinci EMDEL (2001-2005) Centrum Edukacji Niestacjonarnej Politechniki Gdańskiej wybrało system...
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The PWM current source inverter with IGBT transistors and multiscalar model control system
PublicationW niniejszym artykule przedstawiono struktury układów sterowania maszyny indukcyjnej zasilanej z falownika prądu. Przedstawiono metodę modulacji szerokości impulsów dla falownika prądu. Pokazano modele matematyczne maszyny indukcyjnej klatkowej zasilanej z falownika prądu. Przedstawiono trzy układy regulacji sterowania multiskalarnego z czego dwa są nowe. Rozważania teoretyczne zweryfikowano za pomocą badań symulacyjnych.
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Photovoltaic solar cells and modules as the source of electricity in the world and its future in Poland
PublicationJedną z metod ograniczenia emisji CO2 na świecie i w Polsce jest zastępowanie paliw kopalnych odnawialnymi źródłami energii. Systemy fotowoltaiczne, generujące energie elektryczną, są uważane za technologię wpisująca się w politykę zrównoważonego rozwoju dzięki znacznemu postępowi technologicznemu w zakresie ich wytwarzania i znacznej redukcji kosztów tych systemów.W artykule naświetlono postęp, jaki dokonał się w tej dziedzinie...
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Dobre praktyki i narzędzia open source w zwinnym wytwarzaniu oprogramowania
PublicationZwinne wytwarzanie oprogramowania stało się bardzo popularne. Na podstawie projektu MOST Wiedzy przedstawiono procesy i narzędzia wspierające wytwarzanie oprogramowania na Politechnice Gdańskiej. Metodologia DDD (domain-driven design) wspierana przez repozytorium GIT oraz tzw. proces “cherry picking” powoduje, że proces wytwarzania oprogramowania jest elastyczny i efektywny. Dodatkowo wprowadzenie elementów CI (continuous integration),...
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Evaluation of Open Source SIEM for Situation Awareness Platform in the Smart Grid Environment
PublicationThe smart grid as a large-scale system of systems has an exceptionally large surface exposed to cyber-attacks, including highly evolved and sophisticated threats such as Advanced Persistent Threats (APT) or Botnets. When addressing this situation the usual cyber security technologies are prerequisite, but not sufficient. The smart grid requires developing and deploying an extensive ICT infrastructure that supports significantly...
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Application of atmospheric pressure microwave plasma source for hydrogen production from ethanol
PublicationIn contrast to conventional technologies of hydrogen production like water electrolysis or coal gasification we propose a method based on the atmospheric pressure microwave plasma. In this paper we present results of the experimental investigations of the hydrogen production from ethanol in the atmospheric pressure plasma generated in waveguidesupplied cylindrical type nozzleless microwave (915 MHz and 2.45 GHz) plasma source (MPS)....
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Liquefaction of alder wood as the source of renewable and sustainable polyols for preparation of polyurethane resins
PublicationLiquefaction of wood-based biomass gives different polyol properties depending on the reagents used. In this article, alder wood sawdust was liquefied with glycerol and poly(ethylene glycol) solvents. Liquefaction reactions were carried out at temperatures of 120, 150 and 170 °C. The obtained bio-polyols were analyzed in order to establish the process efficiency, hydroxyl number, acid value, viscosity and structural characteristics...
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Automatic sound source localization in disturbing conditions using acoustic vector sensors
PublicationA concept, practical realization and applications of a passive acoustic radar to automatic localization and tracking of sound sources in disturbing conditions were presented in the paper. The device consists of the new kind of multichannel miniature sound intensity sensors and a group of digital signal processing algorithms. The sensitivity of the realized acoustic radar was examined in free sound field. Several kinds of sound...
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Modular high precision high current source for special applications — Simulation and verification
PublicationThis paper presents selected issues concerning realization of high precision high current source for special applications, where high demands of output parameters of such device are required. A new 80 kW prototype of modular high precision high current source is presented, where output current accuracy reaches 5x10-5. This paper presents also results of operation of the simulation model and of the prototype converter. In order...
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Non-isolated resonant quasi-Z-source network DC–DC converter
PublicationA novel non-isolated resonant quasi-impedance (quasi-Z)-source network DC–DC converter is proposed. The resonant impedance source network is derived from the quasi-Z-source network by including the autotransformer-based resonant cell instead of the second inductor of the quasi-Z-network. The leakage inductance of the autotransformer and two resonant capacitors connected in series with the autotransformer windings constitute a high-frequency...
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Boron doped Nanocrystalline Diamond-Carbon Nanospike Hybrid Electron Emission Source
PublicationElectron emission signifies an important mechanism facilitating the enlargement of devices that have modernized large parts of science and technology. Today, the search for innovative electron emission devices for imaging, sensing, electronics, and high-energy physics continues. Integrating two materials with dissimilar electronic properties into a hybrid material is an extremely sought-after synergistic approach envisioning a...
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Comparison of Impedance-Source Networks for Two and Multilevel Buck–Boost Inverter Applications
Publicationmpedance-source networks are an increasingly popular solution in power converter applications, especially in single-stage buck-boost power conversion to avoid additional front-end dc-dc power converters. In the survey papers published, no analytical comparisons of different topologies have been described, which makes it difficult to choose the best option. Thus, the aim of this paper is to present a comprehensive analytical comparison...
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Experimental investigations of commercial gas boiler as a heat source for the domestic micro-CHP
PublicationW pracy przedstawiono wyniki badań przeprowadzonych na prototypowym stanowisku mikrosiłowni domowej ORC z kotłem gazowym jako źródłem ciepła. Wykazano, iż jest możliwa adaptacja komercyjnego kotła gazowego dla potrzeb kogeneracji w skali mikro.
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Step-Up DC/DC Converters With Cascaded Quasi-Z-Source Network
PublicationW artykule zaprezentowano nowe rozwiązania dotyczące przekształtników energoelektronicznych DC-DC podwyższających napięcie z ogniw paliwowych. Istota rozwiązania zawiera się w zastosowaniu kaskadowo połączonych wejściowych obwodów pasywnych typu Quasi-Z, umozliwiających znaczne podwyższanie napięcia z wykorzystaniem stanu parcy zwarć gałęzi tranzystorowych przekształtnika.
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Dynamic variables limitation for backstepping control of induction machine and voltage source converter
PublicationDynamic variables limitation for backstepping control of induction machine and voltage source converter The paper presents the method of control of an induction squirrel-cage machine supplied by a voltage source converter. The presented idea is based on an innovative method of the voltage source converter control, consisting in direct joining of the motor control system with the voltage source rectifier control system. The combined...
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Diatoms Biomass as a Joint Source of Biosilica and Carbon for Lithium-Ion Battery Anodes
PublicationThe biomass of one type cultivated diatoms (Pseudostaurosira trainorii), being a source of 3D-stuctured biosilica and organic matter—the source of carbon, was thermally processed to become an electroactive material in a potential range adequate to become an anode in lithium ion batteries. Carbonized material was characterized by means of selected solid-state physics techniques (XRD, Raman, TGA). It was shown that the pyrolysis...
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Selected problems of high-power sonar sources
PublicationSpecyfika pracy współczesnych sonarów aktywnych wymaga cyklicznego wypełnienia energią szerokiego sektora sondowania. W przypadku użycia płaskich anten nadawczych oznacza to zwykle konieczność skupienia energii akustycznego impulsu nadawczego na stosunkowo małej powierzchni czynnej przetwornika elektroakustycznego (kluczowe znaczenie odgrywa tu częstotliwość pracy systemu). Zjawiska towarzyszące dużym poziomom źródła mogą powodować...
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New effective sources of lysostaphin Staphylococcus simulans
PublicationLizostafyna jest białkiem posiadającym zdolność lizowania ścian komórkowych bakterii z rodzaju Staphylococcus. W pracy przedstawiono konstrukcje dwóch kolejnych układów ekspresyjnych umożliwiających otrzymywanie rekombinantowej lizostafyny w komórkach bakterii Escherichia coli, metodykę oczyszczania białka oraz jego charakterystykę biochemiczną.
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Noise sources in Raman spectroscopy of biological objects
PublicationWe present an overview of noise sources deteriorating the quality of the recorded biological Raman spectra and the ability to determine the specimen composition. The acquired Raman spectra exhibit intense additive noise components or drifts because of low intensity of the scattered light. Therefore we have to apply expensive or bulky measurement setups to limit their inherent noise or to apply additional signal processing to reduce...
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Stirling engines powered by renewable energy sources
PublicationStirling engine is a device that produces mechanical energy using heat from any source of energy, without the need of combustion of any fuel inside the device. Renewable energy sources, which are mostly low-temperature energy sources, can be used to produce mechanical and electrical energy in Stirling engines. The paper presents an overview of the existing prototype Stirling engines designed for using of low-temperature energy...
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Identification of hydroacoustic wave sources of ship in motion
PublicationThis paper deals with results of identification tests of acoustic field spectrum of underwater noise generated by ship in motion. The field is connected with acoustic activity of ship mechanisms and devices in operation. Vibration energy generated by the mechanisms and devices is transferred through ship structural elements to surrounding water where it propagates in the form of acoustic waves of a broad band of frequencies. In...
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Average Redundancy of the Shannon Code for Markov Sources
PublicationIt is known that for memoryless sources, the average and maximal redundancy of fixed–to–variable length codes, such as the Shannon and Huffman codes, exhibit two modes of behavior for long blocks. It either converges to a limit or it has an oscillatory pattern, depending on the irrationality or rationality, respectively, of certain parameters that depend on the source. In this paper, we extend these findings, concerning the Shannon...
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Sources of investment risk in urban regeneration projects
PublicationThe scope of the article includes multidimensional risk analysis of urban regeneration projects, whose base is to identify areas of its occurrence. Authors thoroughly analyze the sources of potential threats and attempts to answer the question, what is their contribution into overall urban regeneration’ investment risk. The target concept will be used to assess the level of investment risk at the stage of initiation, preparation...
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Average Size of a Suffix Tree for Markov Sources
PublicationWe study a suffix tree built from a sequence generated by a Markovian source. Such sources are more realistic probabilistic models for text generation, data compression, molecular applications, and so forth. We prove that the average size of such a suffix tree is asymptotically equivalent to the average size of a trie built over n independentsequences from the same Markovian source. This equivalenceis only known for memoryless...
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Different sources of market information and product innovativeness
PublicationThe purpose of this study is to identify whether the gathering of market information from different sources – i.e. from customers, competitors and other entities – is related to product innovativeness. The relationships proposed so far have not been empirically investigated but they can have important theoretical and practical implications for product innovation. To achieve the purpose of the paper data concerning 287 new products...
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Identification of safety hazards and their sources in tram transport
PublicationBoth in Poland and in most countries of the European Union, the tram infrastructure is extensively expanding. Contemporary low-floor trams are constructed according to different technical assumptions than typical railway vehicles or high floor trams. In Poland such vehicles rides often on lines designed according to standards developed to the classical vehicles. At the same time, the intensity of road traffic and the number of...
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Amplifying the Randomness of Weak Sources Correlated With Devices
PublicationThe problem of device-independent randomness amplification against no-signaling adversaries has so far been studied under the assumption that the weak source of randomness is uncorrelated with the (quantum) devices used in the amplification procedure. In this paper, we relax this assumption, and reconsider the original protocol of Colbeck and Renner using a Santha-Vazirani (SV) source. To do so, we introduce an SV-like condition...
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Sources and Fate of PAHs and PCBs in the Marine Environment
PublicationThe assessment of a hazard resulting from the pollution of the environment by chemical compounds is in principle limited to the determination of their concentrations in its various compartments. But for solving many problems in this context, knowledge of the emission sources, transport pathways, and sites of deposition is of great benefit. By far the largest amounts of pollutants, regardless of where they were discharged, end up...