2021 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2021

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Implementation of Coprocessor for Integer Multiple Precision Arithmetic on Zynq Ultrascale+ MPSoC
- Tomasz Stefański
- Kamil Rudnicki
- Wojciech Żebrowski
2021
Recently, we have opened the source code of coprocessor for multiple-precision arithmetic (MPA). In this contribution, the implementation and benchmarking results for this MPA coprocessor are presented on modern Zynq Ultrascale+ multiprocessor system on chip, which combines field-programmable gate array with quad-core ARM Cortex-A53 64-bit central processing unit (CPU). In our benchmark, a single coprocessor can be up to 4.5 times faster than a single CPU core within the same chip emulating MPA using a software library.
Implementation of Extended Kalman Filter with Optimized Execution Time for Sensorless Control of a PMSM Using ARM Cortex-M3 Microcontroller
- Justas Dilys
- Voitech Stankevič
- Krzysztof Łuksza
2021 Pełny tekst ENERGIES
This paper addresses the implementation and optimization of an Extended Kalman Filter (EKF) for the Permanent Magnet Synchronous Motor (PMSM) sensorless control using an ARM Cortex-M3 microcontroller. A various optimization levels based on arithmetic calculation reduction was implemented in ARM Cortex-M3 microcontroller. The execution time of EKF estimator was reduced from 260.4 μs to 37.7 μs without loss of accuracy. To further reduce EKF execution time, the separation of a Kalman gain and covariance matrices calculation from prediction and measurement state update, a novel method was proposed, and the performance of it an EKF estimator with separation of a Kalman gain and covariance matrices calculation from prediction and measurement state update was analyzed. Simulation and experiments results validate that the proposed technique could provide the same accuracy with less computation time. A tendency of minimum Kalman gain and covariance matrices calculation frequency from rotor electrical frequency was analyzed and are presented in the paper.
Implementation of Haar wavelet, higher order Haar wavelet, and differential quadrature methods on buckling response of strain gradient nonlocal beam embedded in an elastic medium
- Subrat Kumar Jena
- S. Chakraverty
- Mohammad Malikan
2021 Pełny tekst ENGINEERING WITH COMPUTERS
The present investigation is focused on the buckling behavior of strain gradient nonlocal beam embedded in Winkler elastic foundation. The first-order strain gradient model has been combined with the Euler–Bernoulli beam theory to formulate the proposed model using Hamilton’s principle. Three numerically efficient methods, namely Haar wavelet method (HWM), higher order Haar wavelet method (HOHWM), and differential quadrature method (DQM) are employed to analyze the buckling characteristics of the strain gradient nonlocal beam. The impacts of several parameters such as nonlocal parameter, strain gradient parameter, and Winkler modulus parameter on critical buckling loads are studied effectively. The basic ideas of the numerical methods, viz. HWM, HOHWM, and DQM are presented comprehensively. Also, a comparative study has been conducted to explore the effectiveness and applicability of all the three numerical methods in terms of convergence study. Finally, the results, obtained by this investigation, are validated properly with other works published earlier.
Implementation of International Standards of Fiscal and Monetary Transparency - Case of Poland
- Maria Jastrzębska
2021
Research background: Financial managers, investors, lenders, counterparties and citizens should have useful, reliable, timely, complete, comparable, readable information on fiscal and monetary policy. The actions taken and instruments used by fiscal and monetary authorities have an important impact on economic conditions. Purpose of the article: The aim of the article is to assess Poland's compliance with international standards of fiscal transparency and central bank transparency. Research methods: qualitative and descriptive analysis and inductive, deductive reasoning were applied. Findings: Raising the level of fiscal and monetary transparency is supported by compliance with international standards. In Poland, the level of monetary transparency is higher than that of fiscal transparency, with a lack of transparent information about the effects of unconventional state financial policy instruments on the economy and society.
Implementation of Non-Probabilistic Methods for Stability Analysis of Nonlocal Beam with Structural Uncertainties
- Subrat Kumar Subrat
- S. Chakraverty
- Mohammad Malikan
2021 Pełny tekst ENGINEERING WITH COMPUTERS
In this study, a non-probabilistic approach based Navier’s Method (NM) and Galerkin Weighted Residual Method (GWRM) in term of double parametric form has been proposed to investigate the buckling behavior of Euler-Bernoulli nonlocal beam under the framework of the Eringen's nonlocal elasticity theory, considering the structural parameters as imprecise or uncertain. The uncertainties in Young’s modulus and diameter of the beam are modeled in terms of Triangular Fuzzy Numbers (TFN). The critical buckling loads are calculated for Hinged-Hinged (HH), Clamped-Hinged (CH), and Clamped-Clamped (CC) boundary conditions and these results are compared with the deterministic model in special cases, demonstrating robust agreement. Further, a random sampling technique based method namely, Monte Carlo Simulation Technique (MCST) has been implemented to compute the critical buckling loads of uncertain systems. Also, the critical buckling loads obtained from the uncertain model in terms of Lower Bound (LB) and Upper Bound (UB) by the non-probabilistic methods, viz. Navier’s Method (NM) and Galerkin Weighted Residual Method (GWRM), are again verified with the Monte Carlo Simulation Technique (MCST) with their time periods, demonstrating the efficacy, accuracy, and effectiveness of the proposed uncertain model. A comparative study is also carried out among the non-probabilistic methods and Monte Carlo Simulation Technique (MCST) to demonstrate the effectiveness of methods with respect to time. Additionally, a parametric study has been performed to display the propagation of uncertainties into the nonlocal system in the form of critical buckling loads.
Implementation of SiN thin film in fiber-optic sensor working in telecommunication range of wavelengths
- Sandra Pawłowska
- Jakub Gierowski
- Bartłomiej Stonio
- Marcin Juchniewicz
- Mateusz Ficek
- Michał Kruczkowski
- Małgorzata Szczerska
2021 Pełny tekst Scientific Reports
Mirrors are used in optical sensors and measurement setups. This creates a demand for mirrors made of new materials and having various properties tailored to specific applications. In this work, we propose silicon covered with a thin silicon nitride layer as a mirror for near-infrared measurements. SiN layer was deposited on a standard silicon wafer with a Low-Pressure Chemical Vapor Deposition furnace. Then, the created layer was investigated using ellipsometry and scanning electron microscope. Subsequently, the mirror was used as a reflecting surface in a Fabry–Perot fiber-optic interferometer. The mirror performance was investigated for wavelengths used in telecomunication (1310 nm and 1550 nm) and then compared with results obtained with the same measurement setup, with a silver mirror instead of silicon covered with SiN, as reference. Results showed that the proposed mirror can replace the silver one with satisfying results for investigated wavelengths.
Implementation of the Concept of Flexicurity in the Selected Countries of Central Eastern Europe
- Dagmara Nikulin
- Małgorzata Gawrycka
2021 Ekonomista
The CEE countries have to create their own flexicurity policies which would take into account the employment policy guidelines, cultural traditions and socio-economic development. The aim of this article is to examine and evaluate the implementation of the flexicurity concept on the basis of the adopted set of composite indicators. The study covers 9 countries of the CEE region, and the research period covers the years 2007 and 2013. A review of previous research has demonstrated that there are no studies which would take into account a wide range of indicators included in the composite index of flexicurity. Moreover, in the case of CEE countries there is a lack of publications which would compare the degree of flexibility and security of their labour markets or studies that would compare flexicurity indicators for two different moments in time. This article tries to fill this research gap. The analysis of a composite indicator of flexicurity and its component elements shows large differences in the implementation of the flexicurity concept in the individual CEE countries. The labour market in the CEE countries is still characterized by high strictness of Employment Protection Legislation, which adversely affects the outcomes of the labour market. On the other hand, CEE countries have made great efforts in increasing the role of active labour market policies and non-standard forms of work in the last decade. In most of the countries studied the problem is still related to a relatively small share of individuals engaged in life-long learning and to ensuring the security of those working on non-standard employment contracts.
Importance of Bile Composition for Diagnosis of Biliary Obstructions
- Łukasz Krupa
- Robert Staroń
- Dorota Dulko
- Natalia Łozińska
- Alan Mackie
- Neil Rigby
- Adam Macierzanka
- Aleksandra Markiewicz
- Christian Jungnickel
2021 Pełny tekst MOLECULES
Determination of the cause of a biliary obstruction is often inconclusive from serum analysis alone without further clinical tests. To this end, serum markers as well as the composition of bile of 74 patients with biliary obstructions were determined to improve the diagnoses. The samples were collected from the patients during an endoscopic retrograde cholangiopancreatography (ERCP). The concentration of eight bile salts, specifically sodium cholate, sodium glycocholate, sodium taurocholate, sodium glycodeoxycholate, sodium chenodeoxycholate, sodium glycochenodeoxycholate, sodium taurodeoxycholate, and sodium taurochenodeoxycholate as well as bile cholesterol were determined by HPLC-MS. Serum alanine aminotransferase (ALT), aspartate transaminase (AST), and bilirubin were measured before the ERCP. The aim was to determine a diagnostic factor and gain insights into the influence of serum bilirubin as well as bile salts on diseases. Ratios of conjugated/unconjugated, primary/secondary, and taurine/glycine conjugated bile salts were determined to facilitate the comparison to literature data. Receiver operating characteristic (ROC) curves were determined, and the cut-off values were calculated by determining the point closest to (0,1). It was found that serum bilirubin was a good indicator of the type of biliary obstruction; it was able to differentiate between benign obstructions such as choledocholithiasis (at the concentration of >11 µmol/L) and malignant changes such as pancreatic neoplasms or cholangiocarcinoma (at the concentration of >59 µmol/L). In addition, it was shown that conjugated/unconjugated bile salts confirm the presence of an obstruction. With lower levels of conjugated/unconjugated bile salts the possibility for inflammation and, thus, neoplasms increase.
Importance of Conjugation of the Bile Salt on the Mechanism of Lipolysis
- Natalia Łozińska
- Christian Jungnickel
2021 Pełny tekst MOLECULES
We aim to advance the discussion on the significance of the conjugation of bile salts (BS) in our organism. We hypothesize that conjugation influences the rate of lipolysis. Since the rate of lipolysis is a compound parameter, we compare the effect of conjugation on four surface parameters, which contribute to the rate. Since deconjugation is due to gut microbiota, we hypothesize that microbiota may affect the rate of lipolysis. A meta-analysis of literature data of critical micelle concentration, β, aggregation number, and molar solubilization ratio has been performed for the first time. In addition, critical micelle concentration (CMC), interfacial tension, and lipolysis rate measurements were performed. It was found that the unconjugated BS in mixed micelles increases the antagonism between the BS, therefore, increasing the CMC. This correlated with the effect of unconjugated BS on the solubilization capacity of mixed micelles. The collected literature information indicates that the role of the BS and its conjugation in our organism is a key factor influencing the functioning of our organism, where too high levels of unconjugated BS may lead to malabsorption of fat-soluble nutrients. The experimental lipolysis results irrevocably showed that conjugation is a significant factor influencing the rate.
Improved Design Closure of Compact Microwave Circuits by Means of Performance Requirement Adaptation
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
- Leifur Leifsson
2021
Numerical optimization procedures have been widely used in the design of microwave components and systems. Most often, optimization algorithms are applied at the later stages of the design process to tune the geometry and/or material parameter values. To ensure sufficient accuracy, parameter adjustment is realized at the level of full-wave electromagnetic (EM) analysis, which creates perhaps the most important bottleneck due to the entailed computational expenses. The cost issue hinders utilization of global search procedures, whereas local routines often fail when the initial design is of insufficient quality, especially in terms of the relationships between the current and the target operating frequencies. This paper proposes a procedure for automated adaptation of the performance requirements, which aims at improving the reliability of the parameter tuning process in the challenging situations as described above. The procedure temporarily relaxes the requirements to ensure that the existing solution can be improved, and gradually tightens them when close to terminating the optimization process. The amount and the timing of specification adjustment is governed by evaluating the design quality at the current design, and the convergence status of the algorithm. The proposed framework is validated using two examples of microstrip components (a coupler and a power divider), and shown to well handle design scenarios that turn infeasible for conventional approaches, in particular, when decent starting points are unavailable.
Improved Modeling of Microwave Structures Using Performance-Driven Fully-Connected Regression Surrogate
- Sławomir Kozieł
- Peyman Mahouti
- Nurullah Calik
- Mehmet Belen
- Stanisław Szczepański
2021 Pełny tekst IEEE Access
Fast replacement models (or surrogates) have been widely applied in the recent years to accelerate simulation-driven design procedures in microwave engineering. The fundamental reason is a considerable—and often prohibitive—CPU cost of massive full-wave electromagnetic (EM) analyses related to solving common tasks such as parametric optimization or uncertainty quantification. The most popular class of surrogates are data-driven models, which are fast to evaluate, versatile, and easy to handle. Notwithstanding, the curse of dimensionality as well as the utility demands (e.g., so that the model covers sufficiently broad ranges of the system operating conditions), limit the applicability of conventional methods. A performance-driven modeling paradigm allows for mitigating these issue by focusing the surrogate setup process in a constrained domain encapsulating designs being of high quality w.r.t. the assumed figures of interest. The nested kriging framework capitalizing on this idea, renders the constrained surrogate using kriging interpolation, and has been shown to surpass traditional approaches. In pursuit of further accuracy improvements, this work incorporates the performance-driven concept into the fully-connected regression model (FRCM). The latter has been recently introduced in the context of frequency selective surfaces, and combined deep neural networks with Bayesian optimization, the latter employed to determine the network architecture and hyper-parameters. Using two examples of miniaturized microstrip couplers, our methodology is demonstrated to outperform both conventional modeling techniques and nested kriging, with reliable models constructed over multi-dimensional parameters spaces using just a few hundreds of samples.
Improvement of Oxygen Electrode Performance of Intermediate Temperature Solid Oxide Cells by Spray Pyrolysis Deposited Active Layers
- Bartosz Kamecki
- Jakub Karczewski
- Piotr Jasiński
- Sebastian Molin
2021 Advanced Materials Interfaces
Intermediate temperature solid oxide fuel cells oxygen electrodes are modified by active interfacial layers. Spray pyrolysis is used to produce thin (≈500 nm) layers of mixed ionic and electronic conductors: Sm0.5Sr0.5CoO3−δ (SSC), La0.6Sr0.4CoO3−δ (LSC), La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF), and Pr6O11 (PrOx) on the electrode–electrolyte interface. The influence of the annealing temperature on the electrode polarization (area specific resistance—ASRpol) is investigated by impedance spectroscopy of symmetrical electrodes in the temperature range of 400–700 °C. The results show that the introduction of nanocrystalline interlayers promotes an oxygen reduction reaction by extending the active surface area and improved contact between the electrode and the electrolyte. Introducing LSCF, LSC, or SSC interlayer reduces ASRpol by a factor of 4 and PrOx by a factor of 2 against the reference, powder processed LSCF electrode. At 600 °C, the obtained ASRpol values for PrOx, LSCF, LSC, and SSC interlayer are 245, 137, 119, and 107 mΩ cm2, which can be considered very low in comparison to standard powder processed oxygen electrodes. Anode supported single cell with developed LSC/LSCF electrode reveals ≈1.2 W cm−2 power output at 600 °C and maintains stable cell voltage of 0.75 V under 1 A cm−2 during 60 h of the test.
Improvement of the Chimney Effect in Stack Ventilation
- Romana Antczak-Jarząbska
- Krzysztof Pawłowski
- Maciej Niedostatkiewicz
2021 Pełny tekst Applied Sciences-Basel
The article is focused on the airflow in a ventilation system in a building. The work examines the methods which enhance the chimney effect. In this paper, three cases with different chimneys were analyzed for the full-scale experiment. These cases were characterized by different geometrical and material parameters, leading to differences in the intensity of the ventilation airflow. The common denominator of the cases was the room with the air inlet and outlet to the ventilation system. The differences between the experimental cases concerned the chimney canal itself, and more precisely its part protruding above the roof slope. The first experimental case concerned a ventilation canal made in a traditional way, from solid ceramic brick. The second experimental case concerned the part that led out above the roof slope with a transparent barrier, called a solar chimney. In the third experimental case, a rotary type of chimney cap was installed on the chimney to improve the efficiency of stack ventilation. All these cases were used to determine the performance of natural ventilation—Air Change per Hour (CH). Additionally, the paper presents a technical and economic comparison of the solutions used.
Improvements and Spatial Dependencies in Energy Transition Measures
- Marta Kuc-Czarnecka
- Magdalena Olczyk
- Marek Zinecker
2021 Pełny tekst ENERGIES
This article aims to improve one of the newest energy transition measures—the WorldEconomic Forum WEF Energy Transition Index (ETI) and find its driving forces. This paper proposesa new approach to correct the ETI structure, i.e., sensitivity analysis, which allows assessing theaccuracy of variable weights. Moreover, the novelty of the paper is the use the spatial error modelsto estimate determinants of the energy transition on different continents. The results show thatETI is unbalanced and includes many variables of marginal importance for the shape of the finalranking. The variables with the highest weights in ETI did not turn out to be its most importantdeterminants, which means that they differentiate the analysed countries well; nonetheless, theydo not have sufficient properties of approximating the values of the ETI components. The mostimportant components of ETI (with the highest information load) belong to the CO2emissions percapita, the innovative business environment, household electricity prices, or renewable capacitybuildout. Moreover, we identified the clustering of both ETI and its two main pillars in Europe, whichis not observed in America and Asia. The identified positive spatial effects showing that Europeancountries need much deeper cooperation to reach a successful energy transitio
Improvements to the STEAM-based teaching of architectural drawing
- Mateusz Gerigk
2021 Pełny tekst World Transactions on Engineering and Technology Education
The author of this article presents a systemic approach to improving the teaching of architectural drawing courses for engineers in the 21st Century. In this era of rapid development of digital technologies, the traditional teaching structure should be redefined to a purpose-oriented dynamic model. The existing, generally accepted teaching models have already proved successfully based on the practice-oriented STEAM programme, which integrates science, technology, engineering, art and mathematics. The systemic approach proposed in the article is a step forward in the teaching model strongly focusing on the open structure of the model necessary for its future development in this changing environment. The usefulness of the proposed model for the improvement of teaching architectural drawing has been analysed along with the syllabus of the Architectural Drawing course in the Faculty of Architecture at Gdańsk University of Technology, Gdańsk, Poland. The results of on-line teaching during the Covid-19 pandemic restrictions were processed by data analysis. The usefulness of the proposed model in different areas of engineering education is discussed in this article.
Improving Accuracy of Respiratory Rate Estimation by Restoring High Resolution Features With Transformers and Recursive Convolutional Models
- Alicja Kwaśniewska
- Maciej Szankin
- Jacek Rumiński
- Anthony Sarah
- David Gamba
2021 Pełny tekst
Non-contact evaluation of vital signs has been becoming increasingly important, especially in light of the COVID- 19 pandemic, which is causing the whole world to examine people’s interactions in public places at a scale never seen before. However, evaluating one’s vital signs can be a relatively complex procedure, which requires both time and physical contact between examiner and examinee. These re- quirements limit the number of people who can be efficiently checked, either due to the medical station throughput, pa- tients’ remote locations or the need for social distancing. This study is a first step to increasing the accuracy of com- puter vision-based respiratory rate estimation by transfer- ring texture information from images acquired in different domains. Experiments conducted with two deep neural net- work topologies, a recursive convolutional model and trans- formers, proved their robustness in the analyzed scenario by reducing estimation error by 50% compared to low resolu- tion sequences. All resources used in this research, including links to the dataset and code, have been made publicly available.
Improving Clairvoyant: reduction algorithm resilient to imbalanced process arrival patterns
- Jerzy Proficz
- Krzysztof Ocetkiewicz
2021 Pełny tekst JOURNAL OF SUPERCOMPUTING
The Clairvoyant algorithm proposed in “A novel MPI reduction algorithm resilient to imbalances in process arrival times” was analyzed, commented and improved. The comments concern handling certain edge cases in the original pseudocode and description, i.e., adding another state of a process, improved cache friendliness more precise complexity estimations and some other issues improving the robustness of the algorithm implementation. The proposed improvements include skipping of idle loop rounds, simplifying generation of the ready set and management of the state array and an about 90-fold reduction in memory usage. Finally an extension enabling process arrival times (PATs) prediction was added: an additional background thread used to exchange the data with the PAT estimations. The performed tests, with a dedicated mini-benchmark executed in an HPC environment, showed correctness and improved performance of the solution, with comparison to the original or other state-of-the-art algorithms.
Improving methods to calculate the loss of ecosystem services provided by urban trees using LiDAR and aerial orthophotos
- Karolina Zięba-kulawik
- Paweł Hawryło
- Piotr Wężyk
- Piotr Matczak
- Patrycja Przewoźna
- Adam Inglot
- Krzysztof Mączka
2021 URBAN FORESTRY & URBAN GREENING
In this paper we propose a methodology for combining remotely sensed data with field measurements to assess selected tree parameters (diameter at breast height (DBH) and tree species) required by the i-Tree Eco model to estimate ecosystem services (ES) provided by urban trees. We determined values of ES provided by trees in 2017 in Racibórz (a city in South Poland) and estimated the loss of ES from January 1, 2017 to March 5, 2017, a period of changing legislation that temporarily allowed removal of trees on private property without any permission from city authorities. We applied Canopy Height Models (CHM; GSD 1.0 m) generated from two sets of ALS LiDAR point clouds (acquisitions on June 11, 2011 and March 5, 2017) and performed tree crown segmentations using the GEOBIA approach. Physical attributes were estimated for each tree using predictive models, developed based on field tree inventory . The reference areas for parameterizing the segmentation algorithm and assessing tree species composition were established in Racibórz, while reference data required for assessment of DBH were obtained from the MONIT-AIR project (from Municipality of Kraków). We found that in 2017, 988.79 ha of Racibórz (13.2 % of city area) was covered by the crowns of 264 471 trees, providing ES structural values worth over 384 mil €. The structural value of ES lost in the first months of 2017 (during which 5 075 trees were removed) was about 3.5 mil €. We concluded that in the face of information on tree crown cover that is often missing from city databases, tree inventories require application of a combination of multi-source and multi-resolution spatial analyses, including: administrative decisions for tree removal with exact location, predictive modelling of selected biometrical tree information, automatic crown segmentation on CHM and interpretation of regularly updated color infrared (CIR) aerial orthophotos.
Improving social competencies of architecture students through participatory design of marketplace regeneration
- Justyna Borucka
- Piotr Czyż
- Weronika Mazurkiewicz
- Łukasz Pancewicz
- Iga Perzyna
2021 Pełny tekst World Transactions on Engineering and Technology Education
The article discusses the involvement of architecture students in actual urban regeneration projects through participatory design and tray to respond question how it can improve students social competences, and benefit their future careers as architects and urban planners. By using the example of the student workshops conducted in 2019 at the Faculty of Architecture, GdanskTech, the article discusses the specific methods applied in the participatory process and their impact on the improvement of the social competence of students and the educational benefits of using this methodology in university courses. The student workshops were linked to an ongoing project concerned with regeneration of urban markets across Poland, conducted within the framework of the GOSPOSTRATEG program financed by the National Centre for Research and Development in Poland. Real-life experience of students during participation in enterprises like presented seems to be crucial at attaining high level of social competences. This is even more important in the context of the changing role of the architectural profession in the contemporary complex reality.
Improving the regulation of the derivatives market as an objective prerequisite for sustainable development of the global financial system
- Oksana Novak
- Oleksandr Melnychenko
- Oksana Oliinyk
2021 Pełny tekst E3S Web of Conferences
The development of financial markets is characterized by the emergence of new financial instruments, in particular derivatives, the risk level analysis of which is complicated. Counterparties are not always fully aware of and do not adequately assess the potential risks of derivatives, which may lead to large financial losses and sometimes bankruptcies. The purpose of the study is to generalize approaches to regulating derivative markets and analyse the adequacy of regulatory influence to ensure sustainable development of the global financial system. The article analyses the approaches of scientists and regulators of the USA and the EU to the regulation of the derivatives market before and after the financial crisis of 2007-2008. Prior to the crisis, most scholars took a liberal approach to derivatives market regulation and recommended monitoring new instruments and not restricting their circulation in any way, emphasizing that effective counterparty risk management and their propensity for self-preservation can prevent excessive risk-taking. The authors analyse the potential risks of derivatives and conclude that exchange-traded derivatives can cause similar processes of liquidity crisis, and, therefore, need additional regulatory tools to ensure the stability of the financial system