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Publikacje z roku 2022
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Nieświadome sieci neuronowe
- Stanisław Barański
Coraz większą popularność zyskuje usługa predykcji za pomocą sieci neuronowych. Model ten zakłada istnienie serwera, który za pomocą wyuczonej sieci neuronowej dokonuje predykcji na danych otrzymanych od klienta. Model ten jest wygodny, ponieważ obie strony mogą skupić się na rozwoju w swojej specjalizacji. Wystawia on jednak na ryzyko utraty prywatności zarówno klienta, wysyła- jącego wrażliwe dane wejściowe, jak i serwer, udostępniający wy- uczony model sieci neuronowej. Niniejszy rozdział opisuje proces dokonywania nieświadomej predykcji za pomocą sieci neuronowych. Nieświadomość pozwala na dokonanie predykcji za pomocą sieci neu- ronowych przy zachowaniu prywatności danych wejściowych klienta oraz modelu serwera. Umożliwia świadczenie usług, które dotych- czas blokowane były przez regulacje prawne lub brak wiarygodności przetwarzających je systemów.
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Niobate in silicate and phosphate glasses: Effect of glass basicity on crucible dissolution
- Natalia Wójcik
- Sharafat Ali
- Efstratios Kamitsos
- Doris Möncke
Using niobium crucibles for melting phosphate and silicate glasses of various modifier oxide contents, and therefore varying optical basicity (Λ), was found to result in varying dissolution rates of niobate during melting. Because of their high electronic polarizability, even small concentrations of niobates are detectable in the Raman spectra of glasses. Even less than 1 mol% Nb2O5 can be identified, as independently confirmed by SEM‐EDX analysis. Silica‐rich glasses (~60 % SiO2, Λ~0.6) did not show significant Nb dissolution from the crucible, while higher basicity metasilicate glasses (~ 50% SiO2, Λ~0.65) and pyrophosphate glasses (~30% P2O5, Λ~0.7) did show the typical niobate signature in the Raman spectra at 810‐840 cm‐1, depending on composition. While niobium is well dissolved throughout the pyrophosphate glass, metasilicate glasses showed a much more intense Raman signature of niobate units near the outer surface of the glass. Measurements along the cross section of a fractured metasilicate glass showed a steady decrease of the strength of the niobate signature from the surface toward the bulk of the material. Besides correlation with optical basicity, the tendency of melts to dissolve Nb crucible was discussed in terms of the connectivity or polymerization of the network and the corresponding melt viscosity.
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Nitrate and nitrite silver complexes with weakly coordinating nitriles
- Karolina Gutmańska
- Anna Ciborska
- Zbigniew Hnatejko
- Anna Dołęga
Simple system of weak nitrile ligands and silver nitrite/nitrate allowed the formation and isolation of coordination compounds of diverse nuclearity and dimensionality. The extension of the network does not enhance the luminescent properties of the ligands however it gives rise to the new MLCT bands in the visible region.
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NLITED - New Level of Integrated Techniques for Daylighting Education: Preliminary Data on the Use of an E-learning Platform
- Federica Giuliani
- Natalia Sokół
- Niko Gentile,
- Mandana Khanie, Sarey
- Valerio R.M. Lo Verso
- Federica Caffaro
Project NLITED – New Level of Integrated Techniques for Daylighting Education - is an educational project for students and professionals. The project's objective is to create and develop an online eLearning platform with 32 eModules dedicated to daylight knowledge. The project also offers e-learners two summer school training where the theory is put into practice. The platform was launched on January 31, 2022. The paper analyses the participation during the first four months of online activity until May 31, 2022. It discusses which eModules have received the highest participation rate and which have the lowest. These data are compared to the preferences on modules expressed by different panels of experts. The experts expressed their recommendations for specific educational content during workshops conducted in 2021, which led to the definition of the curriculum. Furthermore, participants also fill out an evaluation test on the quality and the usability of the eModule(s) they have taken. This information leads to the amendments of the ePlatform which are in the scope of action for the final year of the NLTED project.
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Noise profiling for speech enhancement employing machine learning models
- Krzysztof Kąkol
- Grazina Korvel
- Bożena Kostek
This paper aims to propose a noise profiling method that can be performed in near real-time based on machine learning (ML). To address challenges related to noise profiling effectively, we start with a critical review of the literature background. Then, we outline the experiment performed consisting of two parts. The first part concerns the noise recognition model built upon several baseline classifiers and noise signal features derived from the Aurora noise dataset. This is to select the best-performing classifier in the context of noise profiling. Therefore, a comparison of all classifier outcomes is shown based on effectiveness metrics. Also, confusion matrices prepared for all tested models are presented. The second part of the experiment consists of selecting the algorithm that scored the best, i.e., Naïve Bayes, resulting in an accuracy of 96.76%, and using it in a noise-type recognition model to demonstrate that it can perform in a stable way. Classification results are derived from the real-life recordings performed in momentary and averaging modes. The key contribution is discussed regarding speech intelligibility improvements in the presence of noise, where identifying the type of noise is crucial. Finally, conclusions deliver the overall findings and future work directions.
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Non-Adaptive Rotor Speed Estimation of Induction Machine in an Adaptive Full-Order Observer
- Marcin Morawiec
- Paweł Kroplewski
- Charles Ikechukwu Odeh
In the sensorless control system of an induction machine, the rotor speed value is not measured but reconstructed by an observer structure. The rotor speed value can be reconstructed by the classical adaptive law with the integrator. The second approach, which is the main contribution of this paper, is the non-adaptive structure without an integrator. The proposed method of the rotor speed reconstruction is based on an algebraic relationship – the rank of the mathematical model of the observer system is not increased. However, the problem with the stabilization of the observer structure does exist. For near to zero rotor speed or in the regenerating mode of an induction machine, the speed observer structure can be unstable. Therefore, in this paper, the new stabilization functions are proposed. The stability is provided by the Lyapunov theorem and the practical stability theorems in which the uncertainty of parameters is considered. In the proposed solution, the newly introduced stabilization functions guarantee observer stability during both the motoring and regenerating conditions at the chosen low rotor speed ranges and for different load torque values. All the theoretical considerations were confirmed by simulation and experimental tests during the chosen working modes and uncertainties of nominal parameters of the induction machine.
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Non-Adaptive Speed and Position Observer of Doubly-Fed Induction Generator
- Marcin Morawiec
- Krzysztof Blecharz
- Arkadiusz Lewicki
The non-adaptive speed and position estimation of a doubly-fed induction generator (DFIG) is presented in this paper. The speed observer is based on the mathematical model of DFIG and to stabilize the structure the Lyapunov method is used. The classic stator field-oriented control to active and reactive power control is used in the sensorless control system. The performance of the proposed algorithm of a speed observer is validated by simulation and experimental results using the 2 kW generator. The stability analysis of the presented solution is confirmed by using the Lyapunov method and practical stability theorems.
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Non-Contact Monitoring of ECG in the Home Environment—Selecting Optimal Electrode Configuration
- Adam Bujnowski
- Kamil Osiński
- Piotr Przystup
- Jerzy Wtorek
Capacitive electrocardiography (cECG) is most often used in wearable or embedded measurement systems. The latter is considered in the paper. An optimal electrocardiographic lead, as an individual feature, was determined based on model studies. It was defined as the possibly highest value of the R-wave amplitude measured on the back of the examined person. The lead configuration was also analyzed in terms of minimizing its susceptibility to creating motion artifacts. It was found that the direction of the optimal lead coincides with the electrical axis of the heart. Moreover, the electrodes should be placed in the areas preserving the greatest voltage and at the same time characterized by the lowest gradient of the potential. Experimental studies were conducted using the developed measurement system on a group of 14 people. The ratio of the R-wave amplitude (as measured on the back and chest, using optimal leads) was less than 1 while the SNR reached at least 20 dB. These parameters allowed for high-quality QRS complex detection with a PPV of 97%. For the “worst” configurations of the leads, the signals measured were practically uninterpretable.
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Non-Contact Temperature Measurements Dataset
- Aleksander Mroziński
The dataset titled The influence of the distance of the pyrometer from the surface of the radiating object on the accuracy of measurements contains temperature measurements using a selection of four commercially available pyrometers (CHY 314P, TM-F03B, TFA 31.1125 and AB-8855) as a function of the measuring distance. The dataset allows a comparison of the accuracy and measuring precision of the devices, which are very important features in the reliable non-contact prediction of COVID-19 symptoms without interference from external disturbances during fast patient recognition.
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Nonconventional 1,8-Diazafluoren-9-One Aggregates for Green Light Enhancement in Hybrid Biocompatible Media
- Aneta Lewkowicz
- Mattia Pierpaoli
- Katarzyna Walczewska-Szewc
- Martyna Czarnomska
- Piotr Bojarski
- Robert Bogdanowicz
- Stanisław Pogorzelski
- Leszek Kułak
- Jakub Karczewski
Organic aggregates currently play a prominent role, mainly for their unique optoelectronic properties in the aggregated state. Such properties can be related to the aggregates’ structure and the molecular packing mode. In the literature, we have well-established models of H and J aggregates defined based on the molecular exciton model. However, unconventional aggregates, the most unrecognized forms, have been generating interest among researchers recently. Within unconventional aggregation, aggregation-induced emission systems (AIE) are considered. In the present work, we discuss the effect of the forming of unconventional aggregation together with the change in dye concentration on the surface energy characteristics of the materials. All materials were prepared as hybrid biocompatible thin films where the matrix is TiO2 or TiO2/carbon nanowalls (CNWs) with the incorporated dye in the form of 1,8-diazafluoren-9-one (DFO). Using the time-resolved emission spectra and the determination of surface parameters from contact angle measurements, we indicated the correlation between the changes in such parameters and the concentration of DFO dye in two types of TiO2 and TiO2/CNW structures. To examine the propensity of DFO for aggregation, the internal energy of the dye was assessed in several aggregate structures using Quantum chemistry calculations. The results emphasize that DFO is an attractive structure in the design of new fluorophores due to its low molecular weight, the presence of a nitrogen atom that provides good coordination properties, and the ability to form hydrogen bonds. Our studies show that when using suitable matrices, i.e., rigid media, it forms the preferred forms of aggregates in the excited state, characterized by high emission efficiency in the band maximum of around 550 nm.
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Non-Isocyanate-Based Waterborne Polyurethanes
- Marcin Włoch
- Iga Carayon
Non-isocyanate polyurethanes (NIPUs) are a greener alternative for the conventional polyurethanes synthesized using toxic and moisture-sensitive di- or polyisocyanates. The most often described method of NIPU synthesis involves the reaction of five-membered cyclic carbonates with amines, and resulting polymers containing primary and secondary hydroxyl groups (so they are also known as polyhydroxyurethanes), which can be further used for the functionalization of such macromolecules. What cannot be omitted is an application of bio-based substrates in the synthesis of NIPUs, which presently may constitute more than 50 wt.% of such NIPU systems. Waterborne non-isocyanate polyurethanes (WNIPUs) can be prepared as solids, solutions, or dispersions by several different synthetic pathways. Broad-spectrum synthesis methods and used compounds may lead to sufficient molecular masses and mechanical properties on a laboratory scale. Some semi-products of such reactions can be further processed into thin films, coatings, hydrogels, or functionalized nanoparticles. Thus, careful selection of substrates, as in the case of isocyanate-based polyurethanes, provides many opportunities for valuable product fabrication. WNIPUs in the form of dispersions may find an application to cast films with great success, whereas the formation of latexes allows for coating formation. Coatings are the largest group of proposed WNIPU applications due to excellent adhesion, gloss, mechanical properties (flexibility and impact resistance), and thermal stability. Hydrogels are just after coatings because they are characterized by favorable mechanical properties and swelling capability. In this chapter, we describe the synthesis and properties of WNIPUs.
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Non-Least Square GNSS Positioning Algorithm for Densely Urbanized Areas
- Jerzy Demkowicz
The paper introduces an essentially new algorithm for calculating the GNSS position as an alternative to the least-square method. The proposed approach can be widely applied to any positioning method that uses multiple position lines for position calculation and is an example ofhow using a numerical solution can improve position accuracy without access to historical data. In essence, the method is based on the adaptation of the median filtering method widely used in the field of image processing, while at the same time applying a combinatorial approach and order statistics. The proposed solution makes it possible to improve on and assess the credibility of a single measurement. The article highlights the differences between the proposed and currently used approaches, as well as their advantages and disadvantages. The algorithm has been extensively tested under various environmental and weather conditions. The tests were carried out in typical and also in very demanding conditions, thus taking into account the real application context, i.e., pedestrian and car navigation in densely urbanized areas.
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Non-Linear Analysis of Structures Utilizing Load-Discretization of Stiffness Matrix Method with Coordinate Update
- Najmadeen Saeed
- Ahmed Manguri
- Marcin Szczepański
- Robert Jankowski
This paper proposes a stiffness method based structural analysis algorithm for geometrically non-linear structures. In this study, the applied load on the joints has been discretized to a sequence of a few loadings applied. Each loading step produces incremental external nodal displacements, which are added to the corresponding coordinates to get a new geometrical shape of the structure. This process is iteratively repeated until the sum of the loading of all iterations matches the total initial applied loading. The size of the increments affects the technique’s accuracy, subsequently affecting the number of iterations. The configuration of non-linear geometrical structures is vital in the work; a slight change of the coordinates makes a considerable variation of nodal displacements. In this paper, three pin-jointed assemblies and a cantilever beam have been examined using the proposed technique; significantly reasonable outcomes emerged, compared to the non-linear approaches, such as Dynamic Relaxation Method (DRM) and Non-linear approach by Kwan. In a numerical sense, the dissimilarity between the results of the conventional Stiffness Matrix (SM) method and the non-linear method is about 228%, while the maximum discrepancy between the proposed approach and the non-linear methods is just above 15%
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Nonlinear material identification of heterogeneous isogeometric Kirchhoff–Love shells
- Bartosz Borzeszkowski
- Izabela Lubowiecka
- Roger Sauer
This work presents a Finite Element Model Updating inverse methodology for reconstructing heterogeneous materialdistributions based on an efficient isogeometric shell formulation. It uses nonlinear hyperelastic material models suitable fordescribing incompressible material behavior as well as initially curved shells. The material distribution is discretized by bilinearelements such that the nodal values are the design variables to be identified. Independent FE analysis and material discretization,as well as flexible incorporation of experimental data, offer high robustness and control. Three elementary test cases and oneapplication example, which exhibit large deformations and different challenges, are considered: uniaxial tension, pure bending,sheet inflation, and abdominal wall pressurization. Experiment-like results are generated from high-resolution simulations withthe subsequent addition of up to 4% noise. Local optimization based on the trust-region approach is used. The results showthat with a sufficient number of experimental measurements, design variables and analysis elements, the algorithm is capableto reconstruct material distributions with high precision even in the presence of large noise. The proposed formulation isvery general, facilitating its extension to other material models, optimization algorithms and meshing approaches. Adaptedmaterial discretizations allow for an efficient and accurate reconstruction of material discontinuities by avoiding overfitting dueto superfluous design variables. For increased computational efficiency, the analytical sensitivities and Jacobians are provided.
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Nonlinear strain gradient and micromorphic one-dimensional elastic continua: Comparison through strong ellipticity conditions
- Victor Eremeev
- Emanuele Reccia
We discuss the strong ellipticity (SE) conditions for strain gradient and micromorphic continua considering them as an enhancement of a simple nonlinearly elastic material called in the following primary material. Recently both models are widely used for description of material behavior of beam-lattice metamaterials which may possess various types of material instabilities. We analyze how a possible loss of SE results in the behavior of enhanced models. We shown that SE conditions for a micromorphic medium is more restrictive than for its gradient counterpart. On the other hand we see that a violation of SE for a primary material affects solutions within enhanced models even if the SE conditions are fulfilled for them.
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NONLINEAR VIBRATION ANALYSIS OF BEAM AND PLATE WITH CLOSED CRACK: A REVIEW
- Samrawit Alemayehu Tewelde
- Marek Krawczuk
The effect of nonlinearity is high sensitivity in damage detection, especially for closed cracks and delamination. This review illustrates the results of several researchers dealing with nonlinear effects caused by the closure of cracks in the structure, i.e., beam and plate structures. Early detection of damage is an important aspect for the structure and, therefore, continuous progress is being made in developing new and effective methods that use nonlinear effects for early detection of damage and barely visible cracks, i.e., closed cracks and delamination, as well as for the determination of crack size and location. After analysing various methods, the merits, drawbacks and prospects of a number of nonlinear vibration methods for structural damage detection are discussed, and recommendations are made for future researchers
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Nonlocal Models of Plates and Shells with Applications in Micro- and Nanomechanics
- Mohammad Malikan
Nowadays, the use of small-scale structures in micro/nanomachines has become more and more widespread. The most important applications of such small-sized parts are in micro-electro-mechanical systems (MEMS) as well as nano-electro-mechanical systems (NEMS) as actuators, sensors, energy harvesters. For example, nanosensors are nanoscale devices that measure physical quantities and convert these to signals that can be detected and analyzed. On the applications of micro/nanosensors in civil engineering, one can state that nanosensors can be developed and used in construction to monitor and/or control the environmental conditions and the materials/structures' performance. As an example, nanosensors can be used to monitor concrete corrosion and micro-cracking. The smart sensor can also be employed for structural health monitoring in bridges and other structures. In this regard, understanding the mechanical response of such structures in various environmental and physical situations is seriously required. For the design and modelling of such a device, one can use various approaches. First, we mention straightforward experiments which need special equipment and result in high costs. Second, molecular dynamics could be used, which requires a lot of computational efforts, in general. Moreover, this method cannot be implemented for all types of nanostructures. Finally, the application of continuum models properly modified for modelling materials and structures at small scales is worth mentioning. Among various enhancements of classic mechanics of continua and structures, we mention the non-local approach related to the description of long-range interactions. In what follows, we apply the third technique based on non-local models and corresponding modelling to thin-walled structures as principal elements of MEMS and NEMS. Moreover, we consider the coupling between mechanical and electromagnetic fields. So this dissertation is based on this approach. Using it, the mechanical behavior of the MEMS and NEMS has been predicted.
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Nonlocalized thermal behavior of rotating micromachined beams under dynamic and thermodynamic loads
- Ahmed E. Abouelregal
- Hamid M. Sedighi
- Mohammad Malikan
- Victor Eremeev
Rotating micromachined beams are one of the most practical devices with several applications from power generation to aerospace industries. Moreover, recent advances in micromachining technology have led to huge interests in fabricating miniature turbines, gyroscopes and microsensors thanks to their high quality/reliability performances. To this end, this article is organized to examine the axial dynamic reaction of a rotating thermoelastic nanobeam under a constant-velocity moving load. Using Eringen’s nonlocal elasticity in conjunction with Euler–Bernoulli theory and Hamilton's principle, the governing equations are derived. It is assumed that the nanobeam is affected by thermal load and the boundary condition is simply supported. The Laplace transform approach is employed to solve the partial differential equations. A numerical example is presented to analyze the effects of the nonlocal parameter, rotation speed and velocity of the static moving load on the dynamic behavior of the system. The numerical results are graphically illustrated and analyzed to recognize the variations of field variables. Finally, in some special cases, our results are compared to those reported in the literature to demonstrate the reliability of the current model.
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Non-Perfect Propagation of Information to a Noisy Environment with Self-Evolution
- Piotr Mironowicz
- Paweł Horodecki
- Ryszard Horodecki
We study the non-perfect propagation of information for evolving a low-dimensional environment that includes self-evolution as well as noisy initial states and analyse the interrelations between the degree of objectivization and environment parameters. In particular, we consider an analytical model of three interacting qubits and derive its objectivity parameters. The numerical analysis shows that the quality of the spectrum broadcast structure formed during the interaction may exhibit non-monotonicity both in the speed of self-dynamics of the environment as well as its mixedness. The former effect is particularly strong, showing that—considering part of the environment as a measurement apparatus—an increase of the external magnetic field acting on the environment may turn the vague measurement into close to ideal. The above effects suggest that quantum objectivity may appear after increasing the dynamics of the environment, although not with respect to the pointer basis, but some other, which we call the generalized pointer or indicator basis. Furthermore, it seems also that, when the objectivity is poor, it may be improved, at least by some amount, by increasing the thermal noise. We provide further evidence of this by analysing the upper bounds on distance to the set of states representing perfect objectivity in the case of a higher number of qubits.
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Non-volatile molecular composition and discrimination of single grape white of chardonnay, riesling, sauvignon blanc and silvaner using untargeted GC–MS analysis
- Bekzod Khakimov
- Inal Bakhytkyzy
- Carsten Fauhl-Hassek,
- Søren Balling Engelsen
This study developed and applied a GC–MS method aiming at molecular fingerprinting of 120 commercial single grape white wines (Chardonnay, Riesling, Sauvignon Blanc and Silvaner) for possible authentication according to grape variety. The method allowed detection of 372 peaks and tentative identification of 146 metabolites including alcohols, organic acids, esters, amino acids and sugars. The grape variety effect explained 8.3% of the total metabolite variation. Univariate tests showed two-thirds of the metabolites being different between grape varieties. Partial least squares-discriminant analysis based classification models were developed for each grape variety and a panel of classifiers (42 metabolites) was established. All the classification models for grape variety showed a high certainty (>91%) for an independent test set. Riesling contained the highest relative concentrations of sugars and organic acids, while concentrations of hydroxytyrosol and gallic acid, common antioxidants in wine, decreased in the order of Chardonnay > Riesling > Sauvignon Blanc > Silvaner.