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Wyniki wyszukiwania dla: TIME-VARIANT RELIABILITY
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Effect of the Cooling Time in Annealing at 350°C on the Phase Transformation Temperatures of a Ni<sub>5</sub><sub>5</sub>Ti<sub>4</sub><sub>5</sub> wt. Alloy
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PROBLEMS OF EXPERIMENTAL DETERMINATION OF COEFFICIENTS OF THE WEAR OF SHIP PIPING SYSTEMS
PublikacjaThe article presents series of considerations relating to experimental evaluation of the reliability of ship piping systems. The aim of this study is to attempt to answer the following questions: What should be the tested element? How to choose the diameter of the tested item? What should be the result of measurements and calculations? How to measure? How to choose the duration of the test? How to choose the sample size and elaborate...
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Aspect-Oriented Management of Service Requests for Assurance of High Performance and Dependability
PublikacjaA new approach to service requests management in case of insufficient hardware resources is proposed. It is based on wide aspects of requests analysis and it assures reliable and fast access to priority services. Requests are analyzed for, among others, time of occurrence, category of user who made the request, type of service, current system load and hardware utilization. Deterministic but dynamic rules help to manage system load...
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Layer of protection analysis in industrial hazardous installations =n Analiza warstw zabezpieczeń w przemysłowych instalacjach podwyższonego ryzyka
PublikacjaIn the paper The Layer of Protection Analysis (LOPA) as a technique for the risk evaluation relating to the hazardous industriall installations performance is presented. The results of the analyses are important in the terms of the safety management process in such installations. Based on obtained estimations deccisions might be made which solutions to be applied in order to mitigate the risk of the hazardous installations performance...
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Rapid Variable-Resolution Parameter Tuning of Antenna Structures Using Frequency-Based Regularization and Sparse Sensitivity Updates
PublikacjaGeometry parameter tuning is an inherent part of antenna design process. While most often performed in a local sense, it still entails considerable computational expenses when carried out at the level of full-wave electromagnetic (EM) simulation models. Moreover, the optimization outcome may be impaired if good initial design is not available. This paper proposes a novel approach to fast and improved-reliability gradient-based...
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Machine Learning Algorithm-Based Tool and Digital Framework for Substituting Daylight Simulations In Early- Stage Architectural Design Evaluation
PublikacjaThe aim of this paper is to examine the new method of obtaining the simulation-based results using backpropagation of errors artificial neural networks. The primary motivation to conduct the research was to determine an alternative, more efficient and less timeconsuming method which would serve to achieve the results of daylight simulations. Three daylight metrics: Daylight Factor, Daylight Autonomy and Daylight Glare Probability have...
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Stationary underwater channel experiment: Acoustic measurements and characteristics in the Bornholm area for model validations
PublikacjaThe underwater acoustical channel is time-variant, and even on small time scales there is often existing no ‘acoustical frozen ocean’. Popular is the use of WSSUS-channel transmission modeling (Wide-Sense Stationary Uncorrelated Scattering) for the stochastic description of bandpass signals in GSM mobile phones with moving participants; since this results in a halved number of model parameters. For underwater sound applications...
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Navigational decision support system during approach manoeuvre in emergency STS transfer operation
PublikacjaThe paper is concerned with the problem of safe trajectory planning for approaching during emergency STS (Ship to Ship) transfer operation with oil spill. The safe trajectory means that the way points does not cross in the area of the environment with the static and dynamic obstacles and at the same time satisfies ship's stopping and speed deceleration performance. The evolutionary path planning algorithm is used to determine trajectory...
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Multiple-Input Multiple-Output Technique for Underwater Acoustic Communication System
PublikacjaThe performance of an underwater acoustic communication (UAC) system is limited due to tough propagation conditions in the UAC channel. Multiple-Input Multiple-Output (MIMO) technique can improve the reliability of the data transmission system, increase its speed, increase its range, and reduce the energy consumption. The paper presents an implementation method of MIMO technique in the form of coding the Space-Time Block Code and...
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Obyś cudze dzieci uczył! Magia zawodu czy przekleństwo wszech czasów? Na wstępie od redaktorki – bardzo osobiście [Teaching as such. A glamorous profession or a curse of all time? Some introductory remarks from the editor]
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Novel fast non-linear electrochemical impedance method for corrosion investigations
PublikacjaThe paper presents a novel approach to corrosion rate monitoring using non-linear electrochemical impedance spectroscopy. The authors propose a new variant of non-linear impedance measurement using amplitude-modulated multi-frequency ac perturbation signal. It allows shortening of measurement duration so it is possible to monitor corrosion rate of the systems experiencing rapid changes. In this way a limitation resulting from lack...
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Frequency Diagnostics of Transformer Insulating Parameters
PublikacjaIn the article is presented experimental analysis and diagnostics of insulating system oil-paper for power transformers, mainly by progressive frequency method – dielectric spectroscopy. In the 1-st part of the article is described base theory about measurement and diagnostics insulating part (oil and paper) of power transformers. In the 2-nd part of article is described measuring method of insulating frequency diagnostics - frequency...
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Validation of dynamic electrochemical impedance spectrograms using autocorrelation function
PublikacjaValidation of impedance data is essential for checking the reliability of experimental data. Kramers – Kronig transformation is used to verify data obtained from classical Electrochemical Impedance Spectroscopy (EIS) measurements. Data obtained from Dynamic Electrochemical Impedance Spectroscopy (DEIS) could be validated in the same way, but in this case, there is no information about internal consistency between every single spectrum...
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Preconditioners with Low Memory Requirements for Higher-Order Finite-Element Method Applied to Solving Maxwell’s Equations on Multicore CPUs and GPUs
PublikacjaThis paper discusses two fast implementations of the conjugate gradient iterative method using a hierarchical multilevel preconditioner to solve the complex-valued, sparse systems obtained using the higher order finite-element method applied to the solution of the time-harmonic Maxwell equations. In the first implementation, denoted PCG-V, a classical V-cycle is applied and the system of equations on the lowest level is solved...
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On geometry parameterization for simulation-driven design closure of antenna structures
PublikacjaFull-wave electromagnetic (EM) simulation tools have become ubiquitous in antenna design, especially final tuning of geometry parameters. From the reliability standpoint, the recommended realization of EM-driven design is through rigorous numerical optimization. It is a challenging endeavor with the major issues related to the high computational cost of the process, but also the necessity of handling several objectives and constraints...
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Application of response surface methodology to optimize solid-phase microextraction procedure for chromatographic determination of aroma-active monoterpenes in berries
PublikacjaMost of scientific papers concern the qualitative or semi-quantitative analysis of aroma-active terpenes in liquid food matrices. Therefore, the procedure based on solid-phase microextraction and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry for determination of monoterpenes in fresh berries was developed. The optimal extraction conditions using divinylbenzene-carboxen-polydimethylsiloxane fiber...
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Collision Risk-Informed Weather Routing for Sailboats
PublikacjaSelected COLREG rules, good seamanship and sheer common sense indicate that it is in a sailboat's interest to follow collision-free routes without relying on large power-driven ships to give way. Until now, however, no method has integrated a sailboat's weather routing with collision risk monitoring and collision avoidance. Therefore, a new deterministic approach to combine the above features within one method is introduced here....
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Secured wired BPL voice transmission system
PublikacjaDesigning a secured voice transmission system is not a trivial task. Wired media, thanks to their reliability and resistance to mechanical damage, seem an ideal solution. The BPL (Broadband over Power Line) cable is resistant to electricity stoppage and partial damage of phase conductors, ensuring continuity of transmission in case of an emergency. It seems an appropriate tool for delivering critical data, mostly clear and understandable...
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How proteins bind to DNA: target discrimination and dynamic sequence search by the telomeric protein TRF1
PublikacjaTarget search as performed by DNA-binding proteins is a complex process, in which multiple factors contribute to both thermodynamic discrimination of the target sequence from overwhelmingly abundant off-target sites and kinetic acceleration of dynamic sequence interrogation. TRF1, the protein that binds to telomeric tandem repeats, faces an intriguing variant of the search problem where target sites are clustered within short fragments...
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Two-Dimensional Gas Chromatography Coupled With Mass Spectrometry in Food Analysis
PublikacjaThe development of instrumental analytical techniques provided the opportunity for in-depth characterization of many food matrices. In particular, the use of gas chromatography coupled with mass spectrometry gives impressive results in terms of quality and authenticity testing, conducting food freshness evaluations and contamination assessments. A new variant of gas chromatography, namely two-dimensional gas chromatography (GC...
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A Review: Applications of the Spectral Finite Element Method
PublikacjaThe Spectral Finite Element Technique (SFEM) has Several Applications in the Sciences, Engineering, and Mathematics, which will be Covered in this Review Article. The Spectral Finite Element Method (SFEM) is a Variant of the Traditional Finite Element Method FEM that Makes use of Higher Order Basis Functions (FEM). One of the most Fundamental Numerical Techniques Employed in the Numerical Simulation is the SFEM, which Outperforms...
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Automatic road traffic safety management system in urban areas
PublikacjaTraffic incidents and accidents contribute to decreasing levels of transport system reliability and safety. Traffic management and emergency systems on the road, using, among others, automatic detection, video surveillance, communication technologies and institutional solutions improve the organization of the work of various departments involved in traffic and safety management. Automation of incident management helps to reduce...
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Expedited Design Closure of Antenna Input Characteristics by Trust Region Gradient Search and Principal Component Analysis
PublikacjaOptimization-based parameter tuning has become an inherent part of contemporary antenna design process. For the sake of reliability, it is typically conducted at the level of full-wave electromagnetic (EM) simulation models. This may incur considerable computational expenses depending on the cost of an individual EM analysis, the number of adjustable variables, the type of task (local, global, single-/multi-objective optimization),...
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Computational aspects of greedy partitioning of graphs
PublikacjaIn this paper we consider a variant of graph partitioning consisting in partitioning the vertex set of a graph into the minimum number of sets such that each of them induces a graph in hereditary class of graphs P (the problem is also known as P-coloring). We focus on the computational complexity of several problems related to greedy partitioning. In particular, we show that given a graph G and an integer k deciding if the greedy...
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Dynamic F-free Coloring of Graphs
PublikacjaA problem of graph F-free coloring consists in partitioning the vertex set of a graph such that none of the resulting sets induces a graph containing a fixed graph F as an induced subgraph. In this paper we consider dynamic F-free coloring in which, similarly as in online coloring, the graph to be colored is not known in advance; it is gradually revealed to the coloring algorithm that has to color each vertex upon request as well...
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PROBABILISTIC ANALYSIS OF A SPACE TRUSS BY MEANS OF A MULTIDIMENSIONAL VARIABLE DESCRIPTION
PublikacjaThe objective of this paper is to present a variant of the point estimate method (PEM) to determine mean values and standard deviations of limit loads of engineering structures. This approach is illustrated by limit state analysis of a space truss, considering geometric and material imperfections. The calculations were performed for different random models, so the influence of random parameters on the limit load of the truss can...
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Eigenfaces, Fisherfaces, Laplacianfaces, Marginfaces – How to Face the Face Verification Task
PublikacjaThis paper describes the exhaustive tests of four known methods of linear transformations (Eigenfaces, Fisherfaces, Laplacianfaces and Marginfaces) in the context of face verification task. Additionally, we introduce a new variant of the transformation (Laplacianface + LDA), and the specific interval-based decision rule. Both of them improve the performance of face verification, in general, however, our experiments show that the...
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Integrating heterogeneous systems with high-dependability requirements by means of web services
PublikacjaWeb services are commonly used on boundaries of heterogeneous components in Service Oriented Architecture (SOA) as they provide a universal communication channel not bound to any particular programming language or run-time platform. This paper describes how web services can be used to integrate heterogeneous systems which serve purposes requiring high dependability, reliability and availability. Examples of such systems include...
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The Concept of Accuracy Analysis of the Vertical Displacements Gained from the Hydrostatic Levelling Systems’ Measurements
PublikacjaAbstract: Nowadays, hydrostatic levelling is a widely used method for the vertical displacements’ determinations of objects such as bridges, viaducts, wharfs, tunnels, high buildings, historical buildings, special engineering objects (e.g., synchrotron), sports and entertainment halls. The measurements’ sensors implemented in the hydrostatic levelling systems (HLSs) consist of the reference sensor (RS) and sensors located on the...
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Wybrane metody przydatne w analizie niezawodności i bezpieczeństwa funkcjonalnego systemów technicznych.
PublikacjaPrzedstawiono wybrane metody przydatne w analizie niezawodności i bezpieczeństwa funkcjonalnego systemów technicznych takie jak: metoda FMECA (failure mode, effect and criticality analysis, FTA (fault tree analysis, RBD (reliability block diagram) RCM (reliability centered maintenance, LCC (life cycle cost) i PMO (preventive maintenance optimising.
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The Use of Big Data in Regenerative Planning
PublikacjaWith the increasing significance of Big Data sources and their reliability for studying current urban development processes, new possibilities have appeared for analyzing the urban planning of contemporary cities. At the same time, the new urban development paradigm related to regenerative sustainability requires a new approach and hence a better understanding of the processes changing cities today, which will allow more efficient...
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Accident susceptibility index for a passenger ship-a framework and case study
PublikacjaThe continuous monitoring and assessment of operational vulnerability and accident susceptibility of passenger ships is crucial from the perspective of ship and passenger safety. Despite the existing solutions for vulnerability monitoring, stemming mainly from watertight door operations, a comprehensive framework for accident susceptibility assessment and monitoring is missing in the literature. Therefore, this paper offers a...
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Magnetic properties of α-KCoPO4 compound with a chiral polar crystal structure
PublikacjaWe have obtained polycrystalline samples of a metastable α variant of KCoPO4 by low temperature (350–400 °C) solid state metathesis reaction of potassium oxalate and ammonium cobalt orthophosphate. The material crystallizes in a polar chiral structure (sg. P63, no. 173). Measurements of magnetic properties reveal antiferromagnetic interactions and no ordering observed down to T = 1.9 K, well below the Weiss temperature |Θcw| =...
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Building modernization located in the conservation protection zone in the aspect of technical conditions
PublikacjaThe paper presents a description of the technical condition of the building after many years of operation and analyzes the impact of the current use and the lack of regular periodic repairs on the technical efficiency of the building. The influence of the technical solutions applied during the construction of the building on the current limitations related to the planned, target change in the way of use was discussed. Variant conceptual...
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Towards a modification of a regulatory framework aiming at bunker oil spill prevention from ships - A design aspect of bunker tanks vents location guided by CFD simulations
PublikacjaAlthough accidental bunker oil spills at seaway are relatively rare events, they can be pose real threat to the natural marine environment. One of the reasons for the bunker spill to occur is a design failure; one of the ways it can demonstrate is an improper location or height of vent heads, leading to a bunker oil discharge during heavy rolling, due to sloshing phenomenon. Design of a ship and her systems is guided by various...
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Influence of Soft Soil Samples Quality on the Compressibility and Undrained Shear Strength – Seven Lessons Learned From the Vistula Marshlands
PublikacjaThis technical article presents the influence of sample quality on the compressibility parameters and undrained shear strength ( c u ) of soft soils from the Vistula Marshlands. The analysis covers: (1) quality of soft soil according to three criteria: void ratio (Δ e / e 0 index), volumetric strain (Δ ɛ v ) and C r / C c ratio; (2) influence of storage time on quality; (3) influence of sample quality on undrained shear strength...
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INFLUENCE OF INLET GEOMETRY ON THE EFFICIENCY OF 1MW STEAM TURBINE
PublikacjaThe process of the design of the 1MW steam turbine includes designing the stator and rotor blades, the steam turbine inlet and exit, the casing and the rotor. A turbine that operates at rotation speeds other than 3000 rpm requires a gear box and generator with complex electronic software. This paper analyses the efficiency of eight turbine variants, including seven inlet geometries and three stages of stator as well as an eight...
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Study of the Performance of DSSS UAC System Depending on the System Bandwidth and the Spreading Sequence
PublikacjaA signal transmitted in an Underwater Acoustic Communication (UAC) system operating in a shallow-water channel suffers from strong time dispersion due to multipath propagation. This causes the Inter-Symbol Interference (ISI) observed in the received signal, which significantly limits the communication system’s reliability and transmission rate. In such propagation conditions, the Direct-Sequence Spread Spectrum (DSSS) method is...
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Multi-Criterial Design of Antennas with Tolerance Analysis Using Response-Feature Predictors
PublikacjaImperfect manufacturing is one of the factors affecting the performance of antenna systems. It is particularly important when design specifications are strict and leave a minimum leeway for a degradation caused by geometry or material parameter deviations from their nominal values. At the same time, conventional antenna design procedures routinely neglect to take the fabrication tolerances into account, which is mainly a result...
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Classification of high-voltage varistors into groups of differentiated quality
PublikacjaThe research was aimed on defining a factor of quality for high-voltage varistors using Non-Destructive Testing (NDT) techniques, which could be applied during the production testing. The newly proposed parameter Q determined on the basis of the lowest resonant frequency fr measured within the preselected frequency range was taken into account. The parameter Q was defined for ZnO structures after firing, without metallized contacts....
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Methodology of semiconductor devices classification into groups of differentiated quality
PublikacjaZaproponowano klasyfikację przyrządów półprzewodnikowych do grup o zróżnicowanej jakości na podstawie ich szumów własnych z zakresu małych częstotliwości. Przedstawiono metodologię umożliwiającą stwierdzenie, czy zaproponowany parametr szumowy X dla danego typu przyrządu półprzewodnikowego może być stosowany do określenia jakości. Sprecyzowano przebieg badań wstępnych bazujących na ocenie wyników pomiarów szumów własnych z zakresu...
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Evaluation of conductive-to-resistive layers interaction in thick-film resistors
PublikacjaSpektroskopia szumowa w zakresie małych częstotliwości jest używana do badania oddziaływania warstwy rezystywnej i przewodzącej w wytwarzanych rezystorach grubowarstwowych. Wprowadzono dwa parametry szumowe do określania stopnia tego oddziaływania. Opisano wyniki przeprowadzonych badań oddziaływania warstw z dwutlenku rutenu, rutenku bizmutu z kontaktami ze złota, platyna-złoto, pallad-srebro, od różnych producentów.
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Self-testing of fully differential multistage circuits using common-mode excitation
PublikacjaPrzedmiotem artykułu jest, zorientowane na uszkodzenia, testowanie wielostopniowych układów w pełni różnicowych. Zaproponowano metodę testowania z zastosowaniem pobudzenia układu testowanego sygnałem wspólnym. Rozważane są dwa warianty metody. Pierwszy wariant wykorzystuje do pobudzenia wejście każdego różnicowego stopnia. Drugi wariant wykorzystuje dodatkowe wejście wzmacniacza operacyjnego i testuje wielostopniowy układ bez jego...
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New trim configurations for laser trimmed thick-film resistors - theoretical analysis, numerical simulation and experimential verification
PublikacjaW pracy przedstawiono nowe podejście do korekcji rezystorów warstwowych polegające na wytwarzaniu dodatkowego kontaktu w celu rozszerzenia zakresu korekcji i uproszczenia projektowania. Ponadto zaprezentowano nową szybką metodę wyznaczania charakterystyk korekcyjnych a także weryfikację eksperymentalną. Przedstawiono wyniki w postaci zakresów korekcji i względnych przyrostów rezystancji w funkcji kształtu dodatkowego kontaktu oraz...
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Acoustic emission for detecting deterioration of capacitors under aging
PublikacjaW pracy przedstawiono wyniki pomiarów kondensatorów foliowych poddanych przyśpieszonemu procesowi starzenia na ramie trwałości. Stwierdzono, że w niektórych typach kondensatorów foliowych istnieje związek między intensywnością sygnału emisji akustycznej mierzonego w kondensatorach po ich wytworzeniu oraz rezystancji izolacji mierzonej po procesie ich starzenia.
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Quality assessment of ZnO-based varistors by 1/f noise
PublikacjaNoise has been used as a diagnostic tool of surge arrester varistor structures comprising of ZnO grains of various type and size. The physical and electrical properties of the measured samples have been described. In the experimental study, the applied measurement system and the results of noise measurements for the selected structures of varistors designed for the continuous working voltage 280 V, 440 V and 660 V have been presented....
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Diagnosis of fully differential circuits based on a fault dictionary implemented in the microcontroller systems
PublikacjaPrzedstawiono nową koncepcję testera wbudowanego bist przeznaczonego do diagnostyki w pełni różnicowych układów analogowych implementowanych w mikrosystemach mieszanych sygnałowo. w trakcie testowania mierzona jest amplituda i faza wyjściowego napięcia różnicowego. procedura detekcji i lokalizacji uszkodzeń bazuje na słowniku uszkodzeń przechowywanym w pamięci programu mikrokontrolera. korzystną cechą przestrzeni pomiarowej wyznaczonej...
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Quality testing methods of foil-based capacitors
PublikacjaKondensatory foliowe są powszechnie stosowanymi elementami pasywnymi w ukłądach zasilania. Dotychczasowe metody oceny ich jakości są długotrwałe oraz zużywają energię. W pracy przedstawiono propozycje szeregu nowych, bardziej efektywnych metod, które mogą być z sukcesem stosowane podczas ich produkcji.
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UAV IN TODAYS PHOTOGRAMMETRY – APPLICATION AREAS AND CHALLENGES
PublikacjaThere a few important factors, that nowadays, unmanned aerial vehicles (UAV) are used by wider community, and for cases and applications, that cannot be performed never before. Small UAVs, as a photogrammetry measurement tool provide flexibility, reliability, are safe and easy to use, can be deployed in minutes, initial measurement can be delivered yet on the field, and final accurate measurements are calculated in a very short...
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DUABI - Business Intelligence Architecture for Dual Perspective Analytics
PublikacjaA significant expansion of Big Data and NoSQL databases made it necessary to develop new architectures for Business Intelligence systems based on data organized in a non-relational way. There are many novel solutions combining Big Data technologies with Data Warehousing. However, the proposed solutions are often not sufficient enough to meet the increasing business demands, such as low data latency while still maintaining high...