2018 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2018

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Internet Rzeczy - rozwiązania modelowe
- Krzysztof Nowicki
- Oskar Piechowski
2018 Automatyka Elektryka Zakłócenia
W pracy omówiono problemy projektowania i realizacji sieci typu internet rzeczy (IoT). Scharakteryzowano podstawowe cechy systemów, które pozwalają na zakwalifikowanie ich do kategorii internet rzeczy. Przedstawiono wyniki testowania małej sieci typu „zrób to sam” zaprojektowanej i wykonanej w duchu idei internetu rzeczy. Oceniono, czy udało się osiągnąć nową jakość i synergiczny efekt wynikający z wykorzystania wielu źródeł danych (zdalnych i lokalnych) w celu umożliwienia komunikującym się urządzeniom podejmowania lepszych decyzji. Zaproponowano, aby uzyskaną sieć testową wykorzystać jako model dydaktyczny sieci IoT, spełniającej rekomendacje ITU w tym zakresie.
Interpolator wykorzystujący filtr z maskowaniem charakterystyki częstotliwościowej
- Marek Blok
2018 Pełny tekst Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
Interpolator o dużej krotności wymaga stosowania dolnoprzepustowych filtrów cyfrowych o bardzo wąskim paśmie przejściowym. Przekłada się to na dużą złożoność obliczeniową i problemy z projektowaniem filtrów interpolacyjnych. W pracy zaproponowano użycie metody FRM rozbijającej filtr o wąskim paśmie przejściowym na grupę filtrów o obniżonych wymaganiach, co zmniejsza liczbę niezerowych współczynników. W rezultacie użycie tego rozwiązania pozwala na obniżenie złożoności obliczeniowej interpolatora.
Interwencjonizm czy liberalizm - jaka polityka podatkowa
- Wojciech Wyrzykowski
2018 Pełny tekst Przedsiębiorczość i Zarządzanie
W makroekonomii stale powraca spór między zwolennikami interwencjonizmu i zwolennikami polityki liberalnej, który w istocie dotyczy tego samego problemu – roli państwa w oddziaływaniu na procesy gospodarcze. Historycznie ukształtowaną rolą każdego rządu jest ochrona indywidualnych wolności i promowania dobrobytu społeczeństwa. Aby pokryć wydatki związane z takimi zadaniami rząd potrzebuje dochodów, które w decydującej części pochodzą z podatków. Skoro, zatem przyjmiemy prostą formułę zależnościową: potrzeby społeczne - finansowanie przez państwo - pobieranie podatków w odpowiedniej wysokości, to nie możliwym założenie braku wpływu państwa na podatników i gospodarkę.Celem artykułu jest wskazanie, w jak dużym stopniu w następstwie kryzysu koncepcji liberalnych, państwo powinno stosować narzędzia interwencjonizmu, wykorzystując narzędzia podatkowe, a przede wszystkim stymulacyjną funkcję podatków, oraz w jakim stopniu zależne jest to od posiadanej strategii podatkowej.
Intra-operative biopsy in chronic sinusitis detects pathogenic Escherichia coli that carry fimG/H, fyuA and agn43 genes coding biofilm formation
- Michał Michalik
- Alfred Samet
- Andrzej Marszałek
- Beata Krawczyk
- Roman Kotłowski
- Alex Nowicki
- Tomasz Anyszek
- Stella Nowicki
- Józef Kur
- Bogdan Nowicki
2018 Pełny tekst PLOS ONE
The aim of this study was to investigate whether or not surgical biopsy of sinus tissue in chronic sinusitis, not responsive to treatment, would detect E. coli. We intended to evaluate E. coli virulence genes, therefore dispute the causal role of such an unusual microorganism in chronic sinusitis, as well as consider effective pathogen-targeted therapy. Patients with E. coli isolated by intra-operative puncture biopsy were included in the study. Genetic analysis of E. coli isolates, including phylogenetic grouping and virulence factor characteristics, were done by multiplex PCR. We identified 26 patients with chronic sinusitis, in which 26 E. coli isolates were cultured. The E. coli isolates belonged mainly to pathogenic phylogenetic group B2, and carried multiple virulence genes. Three genes in particular were present in all (100%) of examined isolates, they were (1) marker agn43 gene for forming biofilm, (2) type 1 fimbriae (fimG/H gene) and (3) yersiniabactin receptor (fyuA). Furthermore, a pseudo-phylogenetic tree of virulence genes distribution revealed possible cooperation between agn43, fimG/H, and fyuA in the coding of biofilm formation. Intra-operative-biopsy and culture-based therapy, targeting the isolated E. coli, coincided with long-term resolution of symptoms. This is the first report demonstrating an association between a highly pathogenic E. coli, chronic sinus infection, and resolution of symptoms upon E. coli targeted therapy, a significant finding due to the fact that E. coli has not been considered to be a commensal organism of the oropharynx or sinuses. We postulate that the simultaneous presence of three genes, each coding biofilm formation, may in part account for the chronicity of E. coli sinusitis.
Introducing agile practices into development processes of safety critical software
- Katarzyna Łukasiewicz
- Janusz Górski
2018 Pełny tekst
In this paper we present AgileSafe - a method which supports introduction of agile practices into safety-critical software development processes. To represent safety assurance constraints resulting from the regulatory context, AgileSafe uses assurance case patterns. The knowledge base of AgileSafe helps the user to select the agile practices relevant for the considered software development project. The corresponding assurance case patterns define the scope of the evidence to be collected to demonstrate that the project meets its safety constraints. The overview of the method is presented with reference to a case study - a project for continuous glucose monitoring-enabled insulin pump system.
Introducing concurrent engineering to space and satellite technology undergraduate course
- Adam Dąbrowski
2018 Pełny tekst
In recent decade concurrent engineering has become a de facto leading methodology of work in space, aeronautics and sometimes even automotive industry. It has been used in designing ESA space missions for 20 years now, with rst Concurrent Design Facility (CDF) built in ESTEC in 1998. Still, it has not become a universal standard in engineering, and universities are specically reluctant to adopt it into their curricula. As a result, virtually no students are accustomed to the method at the time of their graduation. As a countermeasure, ESA Academy has decided to offer multiple hands-on courses in their Teaching and Learning Centre in Redu. The main aim is to broaden the gap between university courses and professional space industry requirements. Such courses include: Concurrent Engineering Workshops, CubeSat Concurrent Engineering and most recently Concurrent Engineering Challenge 2017 which the author of this paper is alumnus. Multiple students have beneted greatly from this courses and have been spreading the knowledge either running courses as tutors or implementing the principles in student organisations. Only a handful of European academia can afford building designated CDFs. However, as this paper shows, implementation of elements of concurrent engineering is possible with limited resources. This papier focuses on concurrent engineering implementation at Gdansk University of Technology. Their recently opened Master's course of Space and Satellite Technologies, backed up by Polish Space Agency is a response for demand for high qualied personnel from Poland's rapid growing space sector. Both tutor and student perspective on concurrent engineering implementation will be presented.
Inverse modeling for fast design optimization of small-size rat-race couplers incorporating compact cells
- Sławomir Kozieł
- Piotr Kurgan
2018 INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING
In the paper, a framework for computationally-efficient design optimization of compact rat-race couplers (RRCs) is discussed. A class of hybrid RRCs with variable operating conditions is investigated, whose size reduction is obtained by replacing ordinary transmission lines with compact microstrip resonant cells (CMRCs). Our approach employs a bottom-up design strategy leading to the development of compact RRCs through rapid design optimization of its building blocks and a subsequent fine tuning to account for parasitic cross-coupling effects. The fundamental component of the proposed method is an inverse CMRC surrogate model, covering a wide range of cell electrical parameters, and enabling a convenient adjustment of coupler bandwidth. Having the surrogate model established, it is possible to produce close-to-optimum CMRC dimensions at a negligible computational cost. The subsequent correction step requires only up to two electromagnetic simulations of the CMRC. The proposed method is demonstrated by designing an RRC for several operational bandwidths. Experimental results are also provided.
Investigating Feature Spaces for Isolated Word Recognition
- Grazina Korvel
- Gintautas Tamulevicus
- Povilas Treigys
- Jolita Bernataviciene
- Bożena Kostek
2018
Much attention is given by researchers to the speech processing task in automatic speech recognition (ASR) over the past decades. The study addresses the issue related to the investigation of the appropriateness of a two-dimensional representation of speech feature spaces for speech recognition tasks based on deep learning techniques. The approach combines Convolutional Neural Networks (CNNs) and timefrequency signal representation converted to the investigative feature spaces. In particular, fractal dimension features of the signal were chosen for the time domain, and two feature spaces were investigated for the frequency domain, namely: frequency tracks obtained from the frequencies and amplitudes of the detected spectral peaks and the modified chromagrams. Both are constructed from a series of short-time Fourier transforms, which were computed along the window speech signal in the time domain. Due to the fact that deep learning requires a sufficiently large training set as the size of the corpus may significantly influence the outcome, thus for the data augmentation purpose, the created dataset was extended by adding various noise levels and mixed with the speech signal. In order to evaluate the applicability of implemented feature spaces for isolated word recognition task, three experiments were conducted: a 10-word, a 70-word, and a 111-word cases were analyzed.
Investigation method and mathematical model of pressure losses in hydraulic rotary motor
- Agnieszka Maczyszyn
2018 Pełny tekst Polish Maritime Research
Tis paper presents a way of determining the coefcient k of the pressure losses Δp (fow drag) in internal ducts 8 Mp of SWSB-63 hydraulic motor. Te coefcient is determined at a fow rate equal to the theoretical capacity Q of the Pt pump feeding the motor , the losses are related to the nominal pressure p in the hydraulic system. Te investigations n followed a model of energy performance of hydraulic rotary motor, proposed by Z. Paszota.
Investigation of an elutable N-propylphosphonic acid chitosan derivative composition with a chitosan matrix prepared from carbonic acid solution
- Szymon Mania
- Robert Tylingo
- Ewa Augustin
- Katarzyna Magdalena Gucwa
- Jakub Szwacki
- Hanna Staroszczyk
2018 Pełny tekst CARBOHYDRATE POLYMERS
Porous chitosan composites using CO2 dissolution procedure and including water soluble N-propylphosphonic chitosan derivative (p-CHI) were obtained and characterized. In contrast to the control material, composites containing modified chitosan distinguished by a rapid moisture absorption and good adhesion to the skin. The FTIR analysis confirmed the presence of propylphosphonic group in the structure of the polymer. The porosity of the materials was in the range 55–77% and decreased with increasong amount of modified chitosan in materials. Solubility of composites was dependent on the content of p-CHI in scaffolds (40%, 25% and 15%) and reached values 11%, 9% and 6,5%, respectively. The values of other parameters like swelling degree (30 g/g) good antioxidant and antimicrobial properties (almost 100% reduction of S.aureus, E.coli and C. albicans growth) and low in vitro cytotoxicity against fibroblasts were highly advantageous for possible biomedical applications of the composites.
Investigation of continuous wave jamming in an IEEE 802.15.4 network
- Jakub Rewieński
- Mateusz Groth
- Łukasz Kulas
- Krzysztof Nyka
2018
This paper presents how continuous wave jamming affects IEEE 802.15.4 network. To this end, an office-based measurement setup has been proposed. Within the measurement area, 25 nodes have been set up in order to create a IEEE 802.15.4 tree-based test network structure. A dedicated jamming device that generates and transmits a continuous wave signal has been developed. Several tests have been conducted and presented to demonstrate the network's vulnerability to jamming attacks for different jammer power levels and its positions across the scene.
Investigation of MIEX® resin sedimentation in the aspect of particle sizes remaining in the supernatant
- Mariola Rajca
- Rafał Bray
- Aleksandra Sokołowska
- Eliza Kulbat
2018 Desalination and Water Treatment
The aim of the study was to evaluate the effectiveness of the MIEX® resin sedimentation process, both new and repeatedly used in hybrid water treatment MIEX®DOC + microfiltration (MF) or ultrafiltration (UF) processes (repeatedly regenerated). The tests consisted of performing 1 h sedimentation of the suspension resin in nonflow conditions and analysis of supernatant water at different process durations. The suspension weight analysis was performed on filters (of porosity 0.45 μm) and granulometric analysis (using a laser granulometer) was accomplished as well. Particles size measurements showed that the average particle size (d50) of the new MIEX® Resin was approximately 120 μm. The repeated use of resin in the water treatment caused significant reduction in suspension grain size (d50 = 31 μm), which could be the result of their abrasion or crumbling during exploitation. The sedimentation for both types of resin was a very effective process. For a new resin just after 5 min of sedimentation, the process efficiency was 99%. For the repeatedly used, regenerated resin the process went forward at much slower rate and 99% effectiveness was obtained scarcely after about 11–12 min of sedimentation. It was established that particles of the new resin, larger than 50 μm, settled much faster than the corresponding particles of the regenerated resin. The smallest particles (<50 μm) settled faster and more effectively in the case of regenerated resin. The obtained test results allowed to determine the optimal sedimentation process parameters as well as the selection of particles with specific, the most favorable sizes (e.g., the rejection of the smallest particles to limit phenomena of blocking membranes used in hybrid water purification system MIEX®DOC + MF/UF).
Investigation of natural frequencies of axially loaded thin-walled columns
- Łukasz Żmuda-Trzebiatowski
2018 Pełny tekst MATEC Web of Conferences
The paper deals with correlation between natural frequencies of two steel thin-walled columns and the corresponding applied load. The structures are made of cold-formed lipped channel sections. The columns lengths were assumed to follow two buckling patterns – global flexural and flexural-torsional buckling. In the thicker structure two material models were considered – linearly-elastic and elastic-perfectly plastic. Numerical computations cover dynamic eigenvalue problem, linear buckling and geometrically (and materially) non-linear analysis. The correlation between squares of natural frequencies and the applied load is linear in both columns. The first natural frequencies drop to zero due to structural buckling. This method, called the Vibration Correlation Technique, allows to predict buckling loads on the basis of measured vibration frequencies of the structures. Plasticity does not act upon corresponding curves – the use of the presented technique is limited to the structures exhibiting elastic buckling behaviour.
Investigation of the Antifungal Activity and Mode of Action of Thymus vulgaris, Citrus limonum, Pelargonium graveolens, Cinnamomum cassia, Ocimum basilicum, and Eugenia caryophyllus Essential Oils
- Katarzyna Magdalena Gucwa
- Sławomir Milewski
- Tomasz Dymerski
- Piotr Szweda
2018 Pełny tekst MOLECULES
The antimicrobial activity of plant oils and extracts has been recognized for many years. In this study the activity of Thymus vulgaris, Citrus limonum, Pelargonium graveolens, Cinnamomum cassia, Ocimumbasilicum, and Eugenia caryophyllus essential oils (EOs) distributed by Pollena Aroma (Nowy Dwór Mazowiecki, Poland) was investigated against a group of 183 clinical isolates of C. albicans and 76 isolates of C. glabrata. All of the oils exhibited both fungistatic and fungicidal activity toward C. albicans and C. glabrata isolates. The highest activity was observed for cinnamon oil, with MIC (Minimum Inhibitory Concentration) values in the range 0.002⁻0.125% (v/v). The MIC values of the rest of the oils were in the range 0.005% (or less) to 2.5% (v/v). In most cases MFC (Minimum Fungicidal Concentration) values were equal to MIC or twice as high. Additionally, we examined the mode of action of selected EOs. The effect on cell wall components could not be clearly proved. Three of the tested EOs (thyme, lemon, and clove) affected cell membranes. At the same time, thyme, cinnamon, and clove oil influenced potassium ion efflux, which was not seen in the case of lemon oil. All of the tested oils demonstrated the ability to inhibit the transition of yeast to mycelium form, but the effect was the lowest in the case of cinnamon oil.
Investigations of local/global buckling of cylindrical metal silos with corrugated sheets and open-sectional column profiles
- Paweł Hajko
- Andrzej Tejchman-Konarzewski
- Michał Wójcik
2018 THIN-WALLED STRUCTURES
Artykuł zajmuje się problemem lokalnego/globalnego wyboczenia w cylindrycznych metalowych silosach z blachy falistej z otwartymi cienkościennymi profilami słupowymi. Obliczenia wykonano w ramach liniowej teorii bifurkacji stosując metodę elementów skończonych w programie ABAQUS. Zbadano obszernie wpływ różnych parametrów (średnica i wysokość silosów, grubość blachy falistej, wielkość fali blachy, rozstaw słupów, przekrój słupów) na występowanie wyboczenia lokalnego. Wyniki porównano z Eurokodem.
Investigations of the optical activity of nonlinear crystals by means of dual-wavelength polarimeter
- Mykola Shopa
- Nazar Ftomyn
2018 OPTICAL ENGINEERING
A dual-wavelength method in high accuracy polarimetry has been successfully tested and applied to measure optical activity (OA) of nonlinear crystals. In proposed polarimetric scheme two neighboring semiconductor laser wavelengths (635 and 650 nm) are used, which increases number of parameters measured simultaneously and improves the data processing. By neglecting dispersion of eigen wave ellipticity in crystals, more efficient elimination of the systematic errors, in comparison with the known HAUP technique, is possible. We have tested our experimental setup on optically inactive lithium niobate crystal and obtained OA in the perpendicular to the optical axis direction for quartz and DKDP crystals.
Investigations on strength and fracture in RC beams scaled along height or length
- Jan Suchorzewski
- Ireneusz Marzec
- Ewelina Korol
- Andrzej Tejchman-Konarzewski
2018
The objective of the present paper is to identify experimentally and theoretically differing failure mechanisms in reinforced concrete beams subjected to four-point bending for a separate variation of the depth and length at the constant thickness. Experiments were performed on reinforced concrete beams under four-point bending. Different failure mechanisms included steel yielding, diagonal tension or shear- compression depending upon the ratio of the shear to the beam depth a/D. The shear strength of beams evidently decreased with increasing a/D-ratio. The experimental results were numerically simulated using two-dimensional finite element analyses under plane stress conditions, based on a coupled elasto-plastic- damage constitutive model for concrete that was enhanced by non-locality in the softening regime. The numerical calculation results satisfactorily captured both the experimental shear strength and failure mechanisms.
Investigations on the removal of hydrophobic odorous volatile organic compounds by biotrickling filtration monitored with electronic nose
- Piotr Rybarczyk
- Bartosz Szulczyński
- Jacek Gębicki
2018 Pełny tekst CHEMICAL ENGINEERING TRANSACTIONS
The presented paper presents the results of research on the removal of selected hydrophobic volatile organic compounds (VOCs) from their mixture with air by means of a trickled-bed biofiltration. The efficiency of the removal of toluene and α-pinene, as model VOCs, in a three-section biotrickling filter is evaluated using GCFID and additionally monitored with an electronic nose. The results show that the removal of the model mixture of VOCs occurs with a satisfactory efficiency i.e. exceeding 80% within 21 days after the system startup when ceramic Rashig rings inoculated with Candida species are packed in a biofilter and the trickling liquid is enriched with a surface active substance.
IP Core of Coprocessor for Multiple-Precision-Arithmetic Computations
- Kamil Rudnicki
- Tomasz Stefański
2018 Pełny tekst
In this paper, we present an IP core of coprocessor supporting computations requiring integer multiple-precision arithmetic (MPA). Whilst standard 32/64-bit arithmetic is sufficient to solve many computing problems, there are still applications that require higher numerical precision. Hence, the purpose of the developed coprocessor is to support and offload central processing unit (CPU) in such computations. The developed digital circuit of the coprocessor works with integer numbers of precision approaching maximally 32 kbits. Our IP core is developed using the very high speed integrated circuit hardware description language (VHDL) and simulated assuming implementation in field-programmable gate arrays (FPGAs). It exchanges data using three 64-bit data buses whereas a code for execution on the coprocessor is fetched from a dedicated 8-bit bus (all buses in AMBA standard - AXI Stream). An instruction set of the coprocessor currently consists of 7 instructions including multiplication, addition and subtraction. The computations can maximally employ 16 registers of the length 32k bits. Simulation results assuming implementation on Zynq system on chip (SoC) show that computations of the factorial (n!) for n=1000 take 326.4 μsec. Such a design currently requires 7982 look-up tables (LUTs), 10400 flip-flops (FFs), 33 block RAMs (BRAMs) and 28 DSP modules. The processor is aimed to provide scalability allowing one to use the developed IP core not only in scientific computing, but also in embedded systems employing encryption based on MPA.
IR and Raman study of oxy-nitride glasses
- Doris Möncke
- Sharafat Ali
- Natalia Wójcik
- Damitris Palles
- Efstratios Kamitsos
- Bo Jonson
2018
Various silicate and phosphate glasses with and without nitride addition were structurally characterized by IR and Raman spectroscopy. The studied glass systems include Na-Ca-P-O-N (1), AE-Si-O-N (with AE=Mg, Ca, Sr, Ba)(2), La-Si-O-N (3) as well as the Na-(Li)-Be-O-(N) (4,5) system. The samples were prepared by different techniques such as remelting of pre-prepared glass samples of the oxide systems with Mg and/or Si3N4 powders at 1000–1500 °C under an air or under nitrogen atmosphere or by using metal hydride as a source of modifier cations.