2019 - Repozytorium publikacji - Politechnika Gdańska

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Mechanizmy mocowe na rynkach energii elektrycznej
- Paweł Bućko
2019 Pełny tekst Przegląd Elektrotechniczny
W artykule scharakteryzowano rozliczenia mocowe związane z dostawą energii elektrycznej. Opisano najważniejsze mechanizmy mocowe, skupiając się głównie na rozwiązaniach stosowanych w krajach europejskich. Na tym tle przedstawiono zasady funkcjonowania rynku mocy w Polsce. Omówiono wyniki pierwszych aukcji krajowych. Wskazano na możliwy wpływ funkcjonowania rynku mocy na rynek energii elektrycznej.
Mechatronics design, modelling and controlling of the Stewart-Gough platform
- Dawid Owoc
- Krzysztof Ludwiczak
- Robert Piotrowski
2019
This paper presents a mechatronics design of a low cost Stewart-Gough platform (SGP) with rotary actuators. The designed SGP is supposed to be applied in a ball & plate control system. The synthesis of the ball & plate control system is also within the subject of the paper. A mechatronics design process of the SGP was conducted with computer-aided design (CAD) software. Unique analytical solutions of an inverse kinematics problem (IKP) of the SGP were presented for both prismatic actuators and rotary actuators. Five geometry constants which affect the final range of movement of the SGP were defined. An interactive movable 3D model of the SGP was created. The 3D model was used to test a range of movement of the SGP and to detect a potential crossing of elements during their motion. A mathematical model of a ball & plate system was designed. A control synthesis was conducted with rapid control prototyping using the MATLAB environment. A prototyped and implemented control law was based on two proportional integral derivative (PID) controllers.
Medical-Grade PCL Based Polyurethane System for FDM 3D Printing—Characterization and Fabrication
- Agnieszka Haryńska
- Justyna Kucińska-Lipka
- Agnieszka Sulowska
- Iga Gubańska
- Marcin Kostrzewa
- Helena Janik
2019 Pełny tekst Materials
The widespread use of three-dimensional (3D) printing technologies in medicine has contributed to the increased demand for 3D printing materials. In addition, new printing materials that are appearing in the industry do not provide a detailed material characterization. In this paper, we present the synthesis and characterization of polycaprolactone (PCL) based medical-grade thermoplastic polyurethanes, which are suitable for forming in a filament that is dedicated to Fused Deposition Modeling 3D (FDM 3D)printers. For this purpose, we synthesized polyurethane that is based on PCL and 1,6-hexamethylene diisocyanate (HDI) with a different isocyanate index NCO:OH (0.9:1, 1.1:1). Particular characteristics of synthesized materials included, structural properties (FTIR, Raman), thermal (differential scanning calorimetry (DSC), thermogravimetric analysis (TGA)), mechanical and surfaces (contact angle) properties. Moreover, pre-biological tests in vitro and degradation studies were also performed. On the basis of the conducted tests, a material with more desirable properties S-TPU(PCL)0.9 was selected and the optimization of filament forming via melt-extrusion process was described. The initial biological test showed the biocompatibility of synthesized S-TPU(PCL)0.9 with respect to C2C12 cells. It was noticed that the process of thermoplastic polyurethanes (TPU) filaments forming by extrusion was significantly influenced by the appropriate ratio between the temperature profile, rotation speed, and dosage ratio.
Medium-sized cyclic bis(anisylphosphonothioyl)- disulfanes and their corresponding cyclic sulfane-structures and most characteristic reactions
- Witold Przychodzeń
- Jarosław Chojnacki
- Łukasz Nierzwicki
2019 NEW JOURNAL OF CHEMISTRY
Cyclic 8-, 9-, 10-, and 12-membered bis(anisylphosphonothioyl)disulfanes were synthesized. Next, structurally related 7 to 9-membered cis and trans sulfanes were isolated as a result of sulfur atom extrusion from the parent cyclic disulfanes. The results of the desulfurization of the disulfanes were compared to the results obtained for desulfurization of the respective bis(anisylphosphodithioates). Cyclic disulfanes predominantly provide trans-sulfanes, and the expansion of their ring sizes causes the cis/trans isomer ratio of the cyclic sulfanes to increase. Moreover, bis(anisylphosphodithioates) mainly afford cis-sulfanes, and the cis/trans isomer ratio is greater than 3 : 1. Mechanistic and stereochemical aspects of cyclic disulfane desulfurization have been presented. Although cis-sulfanes are more stable than their respective trans isomers, the cyclisation is a kinetically controlled reaction, which results in predominance of trans-sulfanes in the case of trans-disulfane desulfurization. Disulfanes exhibit thermal and solvolytic stability. A characteristic persistent deep-blue coloration of methanolic ammonia solutions is an unusual feature of cyclic disulfanes. The mechanism of their ammonolysis has been studied and has been compared to that of the respective reaction performed on acyclic disulfanes. Ammonia solution of an acyclic disulfane is colourless. Detailed X-ray analysis was performed for all trans-disulfanes and cis- and trans-sulfanes. They were compared to each other and to their acyclic or cyclic known analogs that comprise common subunits. 8-, 9-, 10-, and 12-membered disulfanes exist as trans isomers exclusively both in the solid state and in solution. They are more stable than their hypothetical cis isomers. The PSSP torsion angles of cyclic disulfanes lie in the range of 94 - 125o and increase with the size of the ring. The greater stability of the cis-sulfanes can be ascribed to the characteristic anisyl–anisyl stacking. Weak hydrogen bonds (CH. . .O/S) play a role in conformational stabilization and intermolecular interactions. The conformations of cyclic disulfanes and cyclic sulfanes were also preserved in solution. A Karplus relationship has been established between the dihedral angles and vicinal H–P coupling constants for all disulfanes and sulfanes. The effects of solvent on the 1H NMR chemical shifts (ASIS) were associated with the dipole moments of the sulfanes.
Meeting Modernisms in Gdynia
- Robert Hirsch
- Ana Maria Zachariade
- Karol Giełdon
2019 Pełny tekst Studies in History and Theory of Architecture-Studii de Istoria si Teoria Arhitecturii
The paper focused on the architectural heritage of the city of Gdynia, in Poland, built in 1920s and 1930s. The city was established (founded) on the seaside of the Baltic Sea as the only port of Poland – a country that regained independence after Versailles Treaty. The history of the city, built from scratch is outstanding in Europe. Modernist architecture of the city is represented by buildings built for different purposes: housing, public and industrial. The main part of the city is the City Centre, protected as the Monument of History (the highest distinction in Polish law) and inscribed in Tentative List of UNESCO in 2019. Due to the history, the urban layout of the City Centre, designed in 1920s, is the unique example of modernist ideas embodied in reality.
Meso‐scale analyses of size effect in brittle materials using DEM
- Jan Suchorzewski
- Andrzej Tejchman-Konarzewski
- Michał Nitka
- Jerzy Bobiński
2019 Pełny tekst GRANULAR MATTER
The paper describes numerical meso-scale results of a size effect on strength, brittleness and fracture in brittle materials like concrete. The discrete element method (DEM) was used to simulate the size effect during quasi-static splitting tension with the experimental-based meso-structure. The two-dimensional (2D) calculations were carried out on concrete cylindrical specimens with two diameters wherein two different failure modes occurred (quasi-brittle and very brittle with the snap-back instability). Concrete was modelled as a random heterogeneous 4-phase material composed of aggregate particles, cement matrix, interfacial transitional zones and macro-voids, based on x-ray micro-CT-images of the real concrete meso-structure. Attention was paid to the effect of the different specimen diameter on both the strength, brittleness and fracture pattern. Each internal energy component was analyzed in the fracture process zone and beyond it, and compared for the different post-peak behaviour of concrete. The evolutions of the number of broken contacts, coordination number, crack displace - ments and normal contact forces were also shown. Of specific interest was the fracture initiation and formation of two dif - ferent failure modes. Next, the 2D DEM results of a size effect for 4 different specimen diameters were directly compared with corresponding experiments from the research literature. The experimental size effect was realistically reproduced in numerical calculations, i.e. the concrete strength and ductility decreased with increasing concrete specimen diameter. The calculated decreasing strength approached an asymptote with increasing cylindrical specimen diameter within the considered specimen size range.
Method for Clustering of Brain Activity Data Derived from EEG Signals
- Adam Kurowski
- Katarzyna Mrozik
- Bożena Kostek
- Andrzej Czyżewski
2019 Pełny tekst FUNDAMENTA INFORMATICAE
A method for assessing separability of EEG signals associated with three classes of brain activity is proposed. The EEG signals are acquired from 23 subjects, gathered from a headset consisting of 14 electrodes. Data are processed by applying Discrete Wavelet Transform (DWT) for the signal analysis and an autoencoder neural network for the brain activity separation. Processing involves 74 wavelets from 3 DWT families: Coiflets, Daubechies and Symlets. Euclidean distance between clusters normalized with respect to the standard deviation of the whole set of data are used to separate each task performed by participants. The results of this stage allow for an assessment of separability between subsets of data associated with each activity performed by experiment participants. The speed of convergence of the training process employing deep learning-based clustering is also measured.
Method of Decision-Making Logic Discovery in the Business Process Textual Data
- Nina Rizun
- Aleksandra Revina
- Vera Meister
2019 Pełny tekst
Growing amount of complexity and enterprise data creates a need for novel business process (BP) analysis methods to assess the process optimization opportunities. This paper proposes a method of BP analysis while extracting the knowledge about Decision-Making Logic (DML) in a form of taxonomy. In this taxonomy, researchers consider the routine, semi-cognitive and cognitive DML levels as functions of BP conceptual aspects of Resources, Techniques, Capacities, and Choices. Preliminary testing and evaluation of developed method using data set of entry ticket texts from the IT Helpdesk domain showed promising results in the identification and classification of the BP Decision-Making Logic.
Method of earth fault loop impedance measurement without nuisance tripping of RCDs in 3-phase low-voltage circuits
- Stanisław Czapp
2019 Pełny tekst Metrology and Measurement Systems
Verification of electrical safety in low-voltage power systems includes the measurement of earth fault loop impedance. This measurement is performed to verify the effectiveness of protection against indirect contact. The widespread classic methods and meters use a relatively high value of the measuring current (5–20) A, so that they are a source of nuisance tripping of residual current devices (RCDs). The meters dedicated to circuits with RCDs usually use an extremely low value of current (lower than 15 mA), which in many cases it is not acceptable in terms of the measurement accuracy. This paper presents a method of earth fault loop impedance measurement in 3-phase circuits, without nuisance tripping of RCDs – the concept of measurement, the meter structure and the experimental validation. The nuisance tripping is avoided in spite of the use of measuring current value many times higher than that of the rated residual current of RCDs. The main advantage of the proposed method is the possibility of creating values of measuring current in a very wide range, what is very important with regard to accuracy of the measurement.
Method of selecting programming practices for the safety-critical software development projects
- Katarzyna Łukasiewicz
2019 Pełny tekst
In recent years a plan-driven approach traditionally used in safety-critical software development has been put to a test by rapidly changing technologies, more diverse group of clients and volatile market requirements. The need to deliver good quality systems, faster and at lower cost in comparison to competitors encouraged companies to look for more efficient solutions. Agile methodologies are known to successfully address these issues for small, non-critical projects. Presumably agile practices can reduce both cost and time to market when applied to safety-critical projects as well. While benefits can be significant, the main concern are quality and safety assurance. Plan-driven methodologies provide tools for such purpose, which agile methodologies in their pure form lack. The challenge that arises is to elaborate a more easily available and ready-to-use solution that would help safety-critical organizations to streamline their processes with agile practices and to maintain accordance with safety standards and certifications. The goal of the research described in this work was to develop an approach aimed at facilitating the introduction of a more agile approach to the software development process, depending on the characteristics of the project, while maintaining compliance with the required safety standards and regulations, and the AgileSafe method presented in this thesis is the main result of this research. The information about project and about the regulatory context constraining the project and its product are the inputs to the method. User is guided through two main processes of AgileSafe: process which selects the specifications of software development practices to be applied in the Project and a process which results in the set of assurance arguments corresponding to the regulations included in the regulatory context. The two main processes of AgileSafe reflect the main objectives of AgileSafe: to support a hybrid approach to software development based on the tailored practices and to support continuous monitoring of conformance to the mandatory regulatory requirements. In order to further improve the method and tailor its advice to the User’s needs more accurately, the knowledge stored in the method should be reviewed and updated regularly. To validate the proposed AgileSafe method, in the course of the research, three case studies have been conducted in addition to interviews and questionnaires with participation of experts.
Method-Dependent Epidemiological Cutoff Values for Detection of Triazole Resistance in Candida and Aspergillus Species for the Sensititre YeastOne Colorimetric Broth and Etest Agar Diffusion Methods
- A. Espinel-Ingroff
- J. Turnidge
- A. Alastruey-Izquierdo
- F. Botterel
- E. Canton
- C. Castro
- Y.-C. Chen
- Y. Chen
- E. Chryssanthou
- E. Dannaoui
- G. Garcia-Effron
- G. M. Gonzalez
- N. P. Govender
- J. Guinea
- S. Kidd
- M. Lackner
- C. Lass-Flörl
- M. J. Linares-Sicilia
- L. López-Soria
- R. Magobo
- T. Pelaez
- G. Quindós
- M. A. Rodriguez-Iglesia
- M. A. Ruiz
- F. Sánchez-Reus
- M. Sanguinetti
- R. Shields
- Piotr Szweda
- A. Tortorano
- N. L. Wengenack
- S. Bramati
- C. Cavanna
- C. DeLuca
- M. Gelmi
- A. Grancini
- G. Lombardi
- J. Meletiadis
- C. E. Negri
- M. Passera
- J. Peman
- A. Prigitano
- E. Sala
- M. Tejada
2019 ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
Although the Sensititre Yeast-One (SYO) and Etest methods are widely utilized, interpretive criteria are not available for triazole susceptibility testing of Candida or Aspergillus species. We collected fluconazole, itraconazole, posaconazole, and voriconazole SYO and Etest MICs from 39 laboratories representing all continents for (method/agent-dependent) 11,171 Candida albicans, 215 C. dubliniensis, 4,418 C. glabrata species complex, 157 C. guilliermondii (Meyerozyma guilliermondii), 676 C. krusei (Pichia kudriavzevii), 298 C. lusitaniae (Clavispora lusitaniae), 911 C. parapsilosis sensu stricto, 3,691 C. parapsilosis species complex, 36 C. metapsilosis, 110 C. orthopsilosis, 1,854 C. tropicalis, 244 Saccharomyces cerevisiae, 1,409 Aspergillus fumigatus, 389 A. flavus, 130 A. nidulans, 233 A. niger, and 302 A. terreus complex isolates. SYO/Etest MICs for 282 confirmed non-wild-type (non-WT) isolates were included: ERG11 (C. albicans), ERG11 and MRR1 (C. parapsilosis), cyp51A (A. fumigatus), and CDR2 and CDR1 overexpression (C. albicans and C. glabrata, respectively). Interlaboratory modal agreement was superior by SYO for yeast species and by the Etest for Aspergillus spp. Distributions fulfilling CLSI criteria for epidemiological cutoff value (ECV) definition were pooled, and we proposed SYO ECVs for S. cerevisiae and 9 yeast and 3 Aspergillus species and Etest ECVs for 5 yeast and 4 Aspergillus species. The posaconazole SYO ECV of 0.06 µg/ml for C. albicans and the Etest itraconazole ECV of 2 µg/ml for A. fumigatus were the best predictors of non-WT isolates. These findings support the need for method-dependent ECVs, as, overall, the SYO appears to perform better for susceptibility testing of yeast species and the Etest appears to perform better for susceptibility testing of Aspergillus spp. Further evaluations should be conducted with more Candida mutants.
Methodology for assessing end-user requirements in the Ella4Life project: elders’ perspectives about self-monitoring
- Mariusz Kaczmarek
- Magdalena Velciu
- Luiza Spiru
- Adam Bujnowski
- Aleksey Andrushevich
- Edith Birrer
2019
The purpose of this paper is to explore elders’ perspectives about self-monitoring and using specially developed sensor technology for measuring health indicators. The qualitative research method is focus-groups with guidelines that were designed for understanding elder’s requirements about monitoring health indicators. We present them two devices: the first sensor is a device for monitoring of cardiac action potential fixed into an armchair, the second sensor for monitoring vital signs is placed in a bathtub. The people express their needs and expectations regarding the idea of having sensors for monitoring health indicators and body movement in their own house.
Methodology for Processing of 3D Multibeam Sonar Big Data for Comparative Navigation
- Andrzej Stateczny
- Wioleta Błaszczak-bąk
- Anna Sobieraj-Żłobińska
- Weronika Motyl
- Marta Wiśniewska
2019 Pełny tekst Remote Sensing
Autonomous navigation is an important task for unmanned vehicles operating both on the surface and underwater. A sophisticated solution for autonomous non-global navigational satellite system navigation is comparative (terrain reference) navigation. We present a method for fast processing of 3D multibeam sonar data to make depth area comparable with depth areas from bathymetric electronic navigational charts as source maps during comparative navigation. Recording the bottom of a channel, river, or lake with a 3D multibeam sonar data produces a large number of measuring points. A big dataset from 3D multibeam sonar is reduced in steps in almost real time. Usually, the whole data set from the results of a multibeam echo sounder results are processed. In this work, new methodology for processing of 3D multibeam sonar big data is proposed. This new method is based on the stepwise processing of the dataset with 3D models and isoline maps generation. For faster products generation we used the optimum dataset method which has been modified for the purposes of bathymetric data processing. The approach enables detailed examination of the bottom of bodies of water and makes it possible to capture major changes. In addition, the method can detect objects on the bottom, which should be eliminated during the construction of the 3D model. We create and combine partial 3D models based on reduced sets to inspect the bottom of water reservoirs in detail. Analyses were conducted for original and reduced datasets. For both cases, 3D models were generated in variants with and without overlays between them. Tests show, that models generated from reduced dataset are more useful, due to the fact, that there are significant elements of the measured area that become much more visible, and they can be used in comparative navigation. In fragmentary processing of the data, the aspect of present or lack of the overlay between generated models did not relevantly influence the accuracy of its height, however, the time of models generation was shorter for variants without overlay.
Methodology of research on the impact of ramp metering on the safety and efficiency of road traffic using transport models
- Jacek Oskarbski
- Karol Żarski
2019
The methods currently used to assess the impact of Intelligent Transport Systems (ITS) services on traffic safety and efficiency are mainly based on expert assessments, statistical studies or traffic models that need further development. There is no structured, uniform evaluation method to compare the impact of different ITS services and their different configurations. The impact of ITS deployment on the road network adjacent to motorways or expressways is usually not taken into account for simulation studies. The approach presented in the paper takes into account the impact of ITS deployment on road traffic efficiency and safety in areas including major roads and alternative routes. The paper presents a methodology for testing the effectiveness of the implementation of a selected ITS service, which is ramp metering. An approach has been applied in which the impact of ITS services is analyzed with the use of a test road network in macro, meso and microscopic transport models. The evaluation of solutions was carried out on the basis of key traffic efficiency indicators. Surrogate measures were used for the assessment of the impact of ramp metering on road traffic safety.
Methods of assaying volatile oxygenated organic compounds in effluent samples by gas chromatography—A review
- Patrycja Makoś
- Andrzej Przyjazny
- Grzegorz Boczkaj
2019 Pełny tekst JOURNAL OF CHROMATOGRAPHY A
The paper is a review of the procedures for the determination of volatile and semivolatile oxygenated organic compounds (O-VOCs) in effluent samples by gas chromatography. Current trends and outlook for individual steps of the procedure for the determination of O-VOCs in effluents are discussed. The available sample preparation techniques and their limitations are described along with GC capillary columns used for O-VOCs separation and selective and universal detectors used for their determination. The results of determination of O-VOC content in various types of real effluents are presented. The lack of legal regulations regarding the presence of the majority of O-VOCs is pointed out as well as the availability of just a few procedures allowing a comprehensive evaluation of the O-VOC content in effluents.
Methods of Assessing Degradation of Supercapacitors by Using Various Measurement Techniques
- Stanisław Galla
- Arkadiusz Szewczyk
- Janusz Smulko
- Patryk Przygocki
2019 Pełny tekst Applied Sciences-Basel
This article presents the qualitative analyses of the construction of supercapacitor samples. The analyses are based on the suggested thermographic measurements as well as the technique of testing the inherent noise of the investigated element. The indicated assessment methods have been referred to the currently used parameters for the qualitative evaluation of supercapacitors. The approach described in this paper, which introduces additional parameters assessing worn out of supercapacitors, can be included in the so-called non-invasive measurement methods, which allow the assessment of the condition of the sample under test. This article presents the applied measurement stands and verifies of the applicability of measurement methods in relation to the currently used parameters allowing for the qualitative assessment of supercapacitors. The measurement method presented in this article was used to study prototypes of supercapacitors. The measurement results allow for more accurate characterization of the observed element. Conducted tests revealed, at the same time, that one of the proposed evaluation methods, based on measurements of inherent noise of tested supercapacitors, is a method predicting their degradation.
Methods of Assessment of Metal Contamination in Bottom Sediments (Case Study: Straszyn Lake, Poland)
- Eliza Kulbat
- Aleksandra Sokołowska
2019 Pełny tekst ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY
The concentrations of six metals (Zn, Cu, Pb, Ni, Cr, and Cd) were investigated in bottom sediments of Straszyn Lake (North Poland). This study was designed to determine a total content of metals and to assess their mobility and bioavailability. The sequential extraction was used to fractionate metals into five fractions: exchangeable, bound to carbonates, bound to Fe–Mn oxides, bound to organic matter, and residual. The evaluation of sediments contamination degree by metals was performed by applying the geochemical quality guidelines, the pollution load index, and the geo-accumulation index (Igeo). The assessment based on these methods demonstrated that sediments were polluted with Cr and the sediments quality guidelines confirmed these results. Moreover, the average concentrations of Cu, Ni, and Cr were respectively 3.4, 3.9, and 21.2 times higher than their background values. According to ecological risk index and risk assessment code Cd was the most important factor affecting the ecological environment of the Straszyn Lake. The metal speciation analysis demonstrated that the mean percentage of metals in the exchangeable and carbonate fractions decreased in the following order: Cd (59.1%) > Zn (19.8%) = Ni (19.8%) > Pb (16.6%) > Cu (3.3%) > Cr (2.7%). The very strong correlation calculated between all the metals indicated their common origin.
Methods of trend removal in electrochemical noise data – overview
- Łukasz Lentka
- Janusz Smulko
2019 Pełny tekst MEASUREMENT
In this paper we shall review popular methods of trend removal from electrochemical noise time records. The basic principles of operation of the six most popular methods are explained. The proposed methods are: high - pass filtering, Moving Average Removal, polynomial detrending, wavelet detrending, Empirical Mode Decomposition and Variational Mode Decomposition. Estimation of trend removal quality is evaluated using statistical measures like a histogram of noise voltage, power spectral density, the correlati on coefficient and signal power. The advantages, disadvantages, limitations and applications of all of the methods mentioned are presented. Two examples of electrochemical noise data with a different nature of generation are used for assessing the efficien cy of the presented methods. The first set of measurement data concerning electrochemical noise with a thermal drift were observed during uniform corrosion. The second one refers to noise superimposed on a curve of the discharging current of a supercapacit or. This additive noise component is generated by charge redistribution or redox reactions within porous carbon electrodes. A comparison of these methods and an indication of the most suitable one for removing the drift component from the acquired electroc hemical data is summarized in this paper.
Methylmercury and total mercury content in soft tissues of two bird species wintering in the Baltic Sea near Gdansk, Poland
- Małgorzata Rutkowska
- Gabriela Bajger-Nowak
- Diana Kowalewska
- Szymon Bzoma
- Elżbieta Kalisińska
- Jacek Namieśnik
- Piotr Konieczka
2019 CHEMOSPHERE
Of the various forms of Hg occurring in nature, (mono) methylmercury (MeHg) is an especially toxic form and practically all forms of Hg can be converted into MeHg as a result of natural processes. Total mercury (THg) and MeHg were determined in tissues of two piscivorous birds: razorbill Alca torda and black-throated loon Gavia arctica to provide baseline data on current mercury concentrations for liver, kidneys and pectoral muscle mercury concentrations of birds which winter on the south Baltic Sea coast. Intra and inter-specific comparisons were carried out. The study is conducted between winter and autumn and the distributions of mercury in tissues were compared with data in other studies. The following paper contains discussion of the results based on the statistical analysis and ecology aspect. The highest average Hg content was in the liver (loon ≈ 3.86 mg kg−1 dw; razorbill ≈ 1.57 mg kg−1 dw), then in the kidneys (loon ≈ 3.14 mg kg−1 dw; razorbill ≈ 1.53 mg kg−1 dw) and the lowest concentrations were in pectoral muscles (loon ≈ 1.97 mg kg−1 dw; razorbill ≈ 0.67 mg kg−1 dw).
Metoda i system adaptacyjnego sterowania parametrami algorytmu syntezy niskich częstotliwości dźwięków muzycznych
- Piotr Hoffmann
2019 Pełny tekst
W ostatnich latach można zaobserwować bardzo wyraźny i systematyczny wzrost wykorzystywania urządzeń mobilnych jako środka do odtwarzania muzyki, czy odtwarzania filmów w dowolnych warunkach akustycznych. Ich użytkownicy oczekują przy tym jak najlepszych walorów brzmieniowych dźwięku. W niniejszej rozprawie zostały zaproponowane metody, mające na celu poprawę brzmienia urządzeń mobilnych w zakresie niskich częstotliwości i korekcji barwy sygnału muzycznego z uwzględnieniem gatunku muzycznego oraz warunków akustycznych panujących w pomieszczeniu. W pierwszej kolejności przeprowadzono przegląd sposobów korekcji niskich częstotliwości oraz korekcji barwy dźwięku. Przedstawiono przyczyny ograniczeń w zakresie przenoszenia niskich częstotliwości przez urządzenia mobilne i wprowadzanych zniekształceń w odtwarzanym dźwięku. Zaproponowano i przetestowano na kilku bazach muzycznych metodę automatycznego rozpoznawania gatunków muzycznych, której skuteczność w kontekście znanych w literaturze wyników można uznać za wysoką i wystarczającą dla celów przypisania utworu muzycznego do danego gatunku muzycznego. Wykorzystano szereg algorytmów uczących, oceniono ich skuteczność, a także możliwość ich zastosowania w zbudowanej aplikacji. W celu potwierdzenia skuteczności proponowanych algorytmów korekcji dźwięku przeprowadzono szereg testów odsłuchowych, w których słuchacze oceniali jakość zmian dokonanych w sygnale muzycznym. Przenalizowano warunki akustyczne panujące w przykładowych wnętrzach i zaproponowano metodę korekcji sygnału muzycznego za pomocą korektora graficznego uwzględniającego akustykę pomieszczenia, w którym muzyka jest odtwarzana. Otrzymane wyniki przeprowadzonych badań potwierdziły, że uwzględnienie klasyfikacji gatunków muzycznych i akustyki pomieszczeń w procesie poprawy brzmienia sygnałów muzycznych podnosi subiektywną jakość dźwięku, a zaproponowane metody poprawy brzmienia niskich częstotliwości i korekcji barwy są lepiej oceniane od dotychczas znanych i stosowanych algorytmów.