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  • Assessment of Connectivity-based Resilience to Attacks Against Multiple Nodes in SDNs
    • Dorabella Santos
    • Amaro de Sousa
    • Carmen Mas-Machuca
    • Jacek Rak
    2021 Pełny tekst IEEE Access

    In Software Defined Networks (SDNs), the control plane of a network is decoupled from its data plane. For scalability and robustness, the logically centralized control plane is implemented by physically placing different controllers throughout the network. The determination of the number and placement of controllers is known as the Controller Placement Problem (CPP). In the regular (i.e., failure-free) state, the control plane must guarantee a given maximum delay between every switch and its primary controller and a given maximum delay between every pair of controllers. In general, these delay bounds allow multiple solutions and, so, other goals can be used to determine the best CPP solution. In this paper, we assess the connectivity-based resilience to malicious attacks against multiple network nodes of the CPP solutions obtained with three different aims: the regular state delay optimization without any concern about attacks, the regular state delay optimization taking into consideration the worst-case attacks and the resilience optimization to attacks against multiple nodes. We assess the CPP solutions considering attacks of targeted nature (when the attacker has complete knowledge of the data plane) and attacks of non-targeted nature (i.e., random and epidemic attacks). We present computational results providing an analysis of the CPP solutions to the different types of attacks. The main conclusion is that the connectivity-based resilience between the different CPP solutions strongly depends on the network topology, the regular state delay bounds and the type of attacks. Finally, we provide insights on how SDN operators can consider the conducted assessment when deciding the controller placements in their networks.

  • Assessment of Corrosive Behaviour and Microstructure Characterization of Hybrid Friction Stir Welded Martensitic Stainless Steel
    • Dhanesh G. Mohan
    • S Gopi
    • Jacek Tomków
    • Shabbir Memon
    2021 Pełny tekst Advances in Materials Science

    This study examined the effect of induction heating on the microstructure and corrosion characteristics of hybrid friction stir welded AISI 410 stainless steel. Five joints have been produced with different friction stir welding parameters like welding speed, spindle speed, plunge depth, and induction power. Their microstructures were evaluated using a scanning electron microscope, and chemical composition was examined using energydispersive X-ray spectroscopy (EDX). The rate of corrosion was found out via the weight loss method in a 1 M HCL solution. The hybrid friction stir welding method used for this work is induction assisted friction stir welding; the results show that this method could produce sound AISI 410 stainless steel Joints. The experiment results show that the joint made at a spindle speed of 1150 rpm, welding speed 40 mm/min, plunge depth 0.5 mm, and in-situ heat by induction 480°C show a better corrosion resistance property with a fine grain structure.

  • Assessment of diversity and composition of bacterial community in Sludge Treatment Reed Bed systems
    • Przemysław Kowal
    • Slawomir Ciesielski
    • Martyna Godzieba
    • Karolina Fitobór
    • Magdalena Gajewska
    • Katarzyna Kołecka
    2021 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT

    Due to their low emission of odours and lack of the need to apply additional chemical agents, sludge treatment reed beds (STRBs) constitute an economically feasible and eco-friendly approach to sewage sludge management. Correctly designed and operated STRBs ensure effective reduction of the dry matter content coupled with the mineralisation of organic compounds. Successful operation of STRBs relies on complex interactions between the plants and microorganisms responsible for the decomposition of organic matter and nutrient cycling. While the biocenoses of wetland systems dedicated to wastewater treatment have been intensively investigated, in the case of sludge treatment applications, there is a deficit of available microbial data. The aim of this study was to explore the diversity and spatial distribution of the bacteria in three distinct STRBs which differ in maturation and feeding patterns. Analyses of the dry mass and organic matter content showed the general trend of the sludge stabilisation processes advancing through the bed depth, with the best performance in the Matured Continuous Feed (MCF) bed being noted. Samples from the MCF bed showed the statistically greatest biodiversity in relation to the other beds. Moreover, increased biodiversity of microorganisms was observed on the surface of the STRBs and the bottom zone of the MCF equipped with a passive aeration system, which proves the application of such solutions in order to enhance the performance of the process. The results of 16S rRNA gene sequencing revealed that Bacteroidetes, Proteobacteria and Firmicutes contributed approximately 80% of all identified sequences read. Network analysis revealed dominant role of Bacteroidetes in the formation of interspecies coexistence patterns. Nitrospira was the most abundant organism responsible for nitrogen metabolism in the STRBs.

  • Assessment of Fuel Cells’ State of Health by Low-Frequency Noise Measurements
    • Arkadiusz Szewczyk
    • Łukasz Gaweł
    • Kazimierz Darowicki
    • Janusz Smulko
    2021 Pełny tekst ENERGIES

    We proposed applying low-frequency (flicker) noise in proton-exchange membrane fuel cells under selected loads to assess their state of health. The measurement set-up comprised a precise data acquisition board and was able to record the DC voltage and its random component at the output. The set-up estimated the voltage noise power spectral density at frequencies up to a few hundred mHz. We observed the evolution of the electrical parameters of selected cells of different qualities. We confirmed that flicker noise intensity varied the most (more than 10 times) and preceded changes in the impedance or a drop in the output DC voltage (less than 2 times). The data were observed for current loads (from 0.5 to 32 A) far from the permissible load. We deduce that the method can be utilised in industrial conditions to monitor the state of health of the selected cells by noise analysis. The method can be used in real-time when the flicker noise is measured within the range of a few Hz and requires a reasonable amount of averaging time to estimate its power spectral density. The presented method of flicker noise measurement has considerable potential for use in innovative ways of fuel cell quality monitoring.

  • Assessment of OpenMP Master–Slave Implementations for Selected Irregular Parallel Applications
    • Paweł Czarnul
    2021 Pełny tekst Electronics

    The paper investigates various implementations of a master–slave paradigm using the popular OpenMP API and relative performance of the former using modern multi-core workstation CPUs. It is assumed that a master partitions available input into a batch of predefined number of data chunks which are then processed in parallel by a set of slaves and the procedure is repeated until all input data has been processed. The paper experimentally assesses performance of six implementations using OpenMP locks, the tasking construct, dynamically partitioned for loop, without and with overlapping merging results and data generation, using the gcc compiler. Two distinct parallel applications are tested, each using the six aforementioned implementations, on two systems representing desktop and worstation environments: one with Intel i7-7700 3.60 GHz Kaby Lake CPU and eight logical processors and the other with two Intel Xeon E5-2620 v4 2.10 GHz Broadwell CPUs and 32 logical processors. From the application point of view, irregular adaptive quadrature numerical integration, as well as finding a region of interest within an irregular image is tested. Various compute intensities are investigated through setting various computing accuracy per subrange and number of image passes, respectively. Results allow programmers to assess which solution and configuration settings such as the numbers of threads and thread affinities shall be preferred.

  • Assessment of particular abdominal aorta section extraction from contrast-enhanced computed tomography angiography
    • Tomasz Dziubich
    • Artur Skrzynecki
    • Marcin Perdeusz
    2021

    The aim of this work is to improve the accuracy of extraction of a particular abdominal aorta section and to reduce the distortion in three-dimensional Computed Tomography Angiography (CTA) images. Imaging modality and quality plays crucial role in the medical diagnostic process, thus ensuring high quality of images is essential at every stage of acquisition and processing.Noise is defined as a disturbance of the image quality that characterized by the presence of pixels that are not desired in the image. Removing or reducing the occurrence of the noise is still a challenging problem in the image processing field. We selected denoising or smoothing methods, such as Gaussian, anisotropic, Taubin, and Laplace filter. This work was carried out as a part of the aorta segmentation software which can detect and display abdominal aorta ROI. We embedded the denoising methods in the system in order to smoothen and to enhance the detection of the contour and surface of the vasculature, which subsequently leads to more accurate segmentation results and extraction particular segment of aorta. We compare the performance of method by using the aortic segmentation result represented in the form of the Dice Similarity Coefficient. Gaussian smoothing is one noise reduction technique that obtained the best in segmentation (average Dice similarity coefficient 0.9103 ±0.04. The results showed that the segmentation results presented in this work are promising, although not all the visualization was well maintained.

  • Assessment of Tensile Strength Reserve of Asphalt Mixtures at Low Temperatures
    • Marek Pszczoła
    • Cezary Szydłowski
    2021 Pełny tekst

    During winter conditions, low-temperature cracks develop at the surface of the asphalt pavement when tensile thermal stress induced in the asphalt layer during cooling equals and exceeds the tensile strength of the material. The paper presents the results of tensile strength reserve assessment of asphalt mixtures with neat and SBS-polymer modified bitumen application. The tensile strength reservewas calculated as difference between the tensile strength βt(T) obtained from the uniaxial tension stress test (UTST) and the cryogenic (thermal) stress σcry(T) obtained from the thermal stress restrained specimen test (TSRST) at the same temperature T. It can be useful factor assessing the low-temperature properties of asphalt mixtures. It was found that the highest values of tensile strength reserve were obtained for the asphalt mixture with SBS-polymer modified bitumen.

  • Assessment of the devulcanization process of EPDM waste from roofing systems by combined thermomechanical/microwave procedures
    • Xavier Colom
    • Javier Cañavate
    • Krzysztof Formela
    • Alireza Shadman
    • Mohammad Saeb
    2021 Pełny tekst POLYMER DEGRADATION AND STABILITY

    Ethylene-propylene-diene rubber (EPDM) is a elastomer widely used in common industrial applications. EPDM can be shaped into sheets and employed as isolating material for roofing systems. In this study, scraps of EPDM from commercial, industrial and residential roofing systems were treated by combined thermo-mechanical and microwave devulcanization processes including peroxide of benzoyl (BPO). The devulcanized EPDM (Dev-EPDM) was characterized by cross-link density, Horikx plot, sol fraction content, SEM and TGA analysis. In order to assess the effect of the different factors implied (type of devulcanization process, temperature and amount of BPO), the Fractional Factorial Design (FFD) method has been applied. The obtained results show that, when thermo-mechanical and microwave methods are combined, produce an intense devulcanization effect. It was also found that the presence of BPO has significative influence in the devulcanization and that the effect of the temperature is related to the amount of BPO.

  • Assessment of the factors influencing on the formation of energy-oriented modes of electric power consumption by water-drainage installations of the mines
    • Oleg Sinchuk
    • Igor Sinchuk
    • Tetyana Beridze
    • Yulii Filipp
    • Kyrylo Budnikov
    • Oleg Dozorenko
    • Ryszard Strzelecki
    2021 Pełny tekst Mining of Mineral Deposits

    Purpose. Performing the analysis to determine energy-efficient modes and assess the characteristics of the main indicators of electric power consumption by mine water-drainage installations based on the developed research mathematical model. Methods. To achieve the purpose set, a methodology is used to develop the multiple multifactor correlation-regression modeling with respect to the modes of electric power consumption by electrical and mechanical complexes of mine waterdrainage installations. The amount of consumed electric power is found as an effective feature. The expediency of using the nonlinear multiple regression analytical ratios has been substantiated during the model development. A comparative analysis of a multiple multifactor regression model, presented in the form of a power and linear function, has been performed. Findings. The expediency of using a multiple multifactor regression model in the form of a power function has been substantiated. The elaborated quantitative values of the factors of electric power consumption by electrical and mechanical complexes of mine waterdrainage installations have become the basis for the introduction of innovative technological solutions at the relevant iron ore enterprises to optimize the cost characteristics of the electric power consumption. Originality. For the first time for the analysis and assessment of the operating modes of the main water-drainage installations of mines, the use of mathematical modeling based on the multiple correlation-regression method is proposed. The developed model takes into account a complex of technological parameters of influence on the water-pumping process. The analysis of the proposed model makes it possible to identify significant factors influencing the modes of electric power consumption by electrical and mechanical complexes for constructing an algorithm for optimal control of this process in the cost-target direction. Practical implications. The analysis of the obtained results of mathematical and statistical modeling makes it possible to take into account the complex of technological parameters of the influence on the water-pumping process, to identify and assess the modes of electric power consumption by the main waterdrainage installations, as well as to obtain the initial data for the development of the structure of the control algorithm for mine stationary installations of this type in the cost-target aspect.

  • Assessment of the ice jam potential on regulated rivers and reservoirs with the use of numerical model results
    • Tomasz Kolerski
    2021 Pełny tekst COLD REGIONS SCIENCE AND TECHNOLOGY

    This study presents an attempt at estimating the jam potential on rivers with significant anthropogenic intervention in the course or flow characteristics of the river. The DynaRiCE model was used for forecasting both the place and time of an ice jam occurrence. In this modified method, two ice parameters are subjected to analysis, namely the relative ice-to-water velocity (vi/vw),and the ice thickness to single floe thickness (ηi/η0). Both variables were analyzed at two locations; first spot is the Odra River near Słubice-Frankfurt bridge (between 581 and 586 km), and the second is the Vistula section between the existing Włocławek dam (674.75 river km) and the planned Siarzewo dam (706.38 river km), covering a 31.6 km reach. Once the model is implemented in the selected areas, the numerical simulations were processed and the obtained results were analyzed in terms of ice accumulation and jamming. The results on both rivers shown some potential of ice jamming, due to the planned engineering works. In the case of the Odra river, it was indicated that ice jam potential increased during the ice run of high concentration in the average flow conditions. For the Vistula river two locations for ice jamming were designated and for both of the points an increase of the ice thickness by about 60% from the initial, single flow thickness was observed. Also in this case, the area-averaged ice velocity in an initially specified location drops below 15% of the average water velocity in that area. According to the used methodology, both cases are classified as ‘ice jam probable’ type.

  • Assessment of the Influence of Road Infrastructure Parameters on the Behaviour of Drivers and Pedestrians in Pedestrian Crossing Areas
    • Marcin Budzyński
    • Anna Gobis
    • Lucyna Gumińska
    • Łukasz Jeliński
    • Mariusz Kieć
    • Piotr Tomczuk
    2021 Pełny tekst ENERGIES

    Pedestrians are participants and, most likely, fatalities in every third road traffic accident in Poland. Over 30% of all fatalities on Polish roads are pedestrians. Accidents with pedestrians are very often the result of various factors related to the infrastructure and behaviour of pedestrians and drivers. The objective of the work was to assess driver and pedestrian behaviour in pedestrian crossing areas. The research also served as a pilot study for similar work to be conducted across Poland, and constituted the basis for monitoring the behaviour of road users in the area of pedestrian crossings. Parameters which must be analysed were identified on the basis of field studies. Principles of selecting test sites were adopted, and measurement methods for pedestrian crossing areas are presented. The influence of the location of the selected test cross-section infrastructure parameters on the behaviour of road users in pedestrian crossing areas is demonstrated. The results of the study will be used as a basis for new solutions involving pedestrian crossing infrastructure designed to improve pedestrian safety. The results were also used in formulating new regulations for the design and maintenance of pedestrian crossings and recommendations for road safety auditors.

  • Assessment of User Mobility’s Influence on System Loss in Several Body-to-Body Scenarios
    • Filipe D. Cardoso
    • Manuel M. Ferreira
    • Andrzej Ambroziak
    • Kenan Turbić
    • Luis M. Correia
    2021 Pełny tekst

    In this paper, Body-to-Body communications in indoor and outdoor environments for different on-body antenna configurations and different mobility scenarios were studied, based on system loss measurements at 2.45 GHz. The main objective is to properly characterise the influence of the Transmitter-Receiver configuration on system loss and fast fading behaviour, the latter being modelled by the Rice Distribution. Globally, it is observed that there is no significant difference on the measured average system loss between indoor and outdoor environments, but a strong dependence is seen on the configuration of the antennas and on the mobility scenario. Concerning the Rice Factor, as expected, higher values were obtained in outdoor environments, due to the lower level of multipath, the difference to the indoor case being below 4 dB, depending on the mobility environment and on the positioning of the antennas.

  • ASSESSMENT OF VOLATILE ORGANIC COMPOUNDS EMISSIONS FROM RECYCLED LOW-DENSITY POLYETHYLENE STREAMS
    • Jerzy Korol
    • Aleksander Hejna
    • Mariusz Marć
    2021 Pełny tekst

    The recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for the potential methods of their utilization. Nevertheless, it should not be forgotten that recycled plastics are not pure materials, and they still may show an unfavorable environmental impact. They may contain different contaminants accumulated during processing processes, as well as their use. Moreover, post-consumer plastics may be partially degraded due to the actions of stress, temperature, or environmental conditions. Therefore, it is imperative to investigate the actual environmental impact and eco-friendliness of recycled plastics. In the presented paper, we analyzed the volatile organic compounds emissions from recycled low-density polyethylene streams. Results indicated that the application of recycled plastics should not be indisputably considered the environmentally-friendly solution.

  • Assessment of wastewater quality indicators for wastewater treatment influent using an advanced logistic regression model
    • Bartosz Szeląg
    • Mohammad Javad Mehrani
    • Jakub Drewnowski
    • Monika Majewska
    • Grzegorz Łagód
    • Sheena Kumari
    • Faizal Bux
    2021 Desalination and Water Treatment

    Influent quality indicators play a significant role in wastewater treatment plant performance due to their correlation with reactor operations and effluent quality. However, selecting a specific/best parameter indicator for predicting influent wastewater quality is one of the challenges in wastewa- ter treatment. This study, therefore, focused on determining suitable variables as influent quality indicators. For this purpose, a logistic regression model involving different inflow parameters from two wastewater treatment plants in Poland was used to identify the best wastewater parameter as a suitable indicator for operational monitoring, process control and simulation purpose. The results showed that the model is flexible enough to simultaneously predict two or three effective waste- water quality indicators. Furthermore, the sensitivity analysis results showed a strong nonlinear relationship between the complex values of total nitrogen, total phosphorus and suspended solids.

  • Asymmetrical Modes in Polyphase Motors and Drives
    • Valentin Tomasov
    • A Usoltsev
    • Marcin Morawiec
    • Paweł Szczepankowski
    • Ryszard Strzelecki
    2021 Russian Electrical Engineering

    The effect of power supply and/or motor asymmetry on the phase-load distribution and the ripple of electromagnetic torque in a polyphase drive is studied by the method of symmetrical components. It is shown that the presence of asymmetry causes the mapping of all harmonics in the supply voltage into all planes of symmetrical components and eliminates the possibility of independent control of harmonics. The dynamic model of a five-phase squirrel-cage induction motor demonstrates that even minor phase or amplitude asymmetry causes asymmetry in the phase load and ripple of the electromagnetic torque. Their level eliminates the possibility of continuous operation of the motor in this mode and requires the use of control systems that provide load balance in the intact phases.

  • Atmospheric deposition of microplastics in the coastal zone: Characteristics and relationship with meteorological factors
    • Karolina Szewc
    • Bożena Graca
    • Anna Dołęga
    2021 SCIENCE OF THE TOTAL ENVIRONMENT

    The quantitative and qualitative compositions of microplastics (MPs) deposited from the atmosphere in the coastal zone were analysed. Moreover, links between MP deposition and meteorological factors (air humidity, wind speed, precipitation height, and air mass trajectories) were investigated

  • Atom-economic thiophosphoroselenenylations of C–H acid esters and amides
    • Arkadiusz Majewski
    • Witold Przychodzeń
    2021 Pełny tekst SYNTHETIC COMMUNICATIONS

    Three improved thiophosphoroselenenylation procedures of CHacids, including derivatives of malonic and acetyl-, phosphono-, 4-nitrophenyl- and 3-pyridylacetic acids, have been described and compared to previously reported thiophosphoroselenylation of diethyl malonate using bis(disopropoxyphosphinothioyl)diselenide alone or with the aid of methyl iodide. The use of iodine makes it possible to utilize both equivalents of the selenenylating agent. The procedures work well for the majority of nucleophiles in a pKa range between more acidic malononitrile or Meldrum acid and less acidic phenylacetates. The reaction carried out on diethyl malonate in boiling rectified ethanol yields selenoacetate, which cannot be obtained by direct phosphoroselenenylation. Crystal structure of one of the selenomalonamides confirms the stabilization effects of both carbonyl oxygens on selenium atom. The P-Se bond splitting, using TBAF in 3-molar excess in the presence of alkylating agent yields the respective C,Se-dialkyl derivatives.

  • Automatic Identification System (AIS) Dynamic Data Integrity Monitoring and Trajectory Tracking Based on the Simultaneous Localization and Mapping (SLAM) Process Model
    • Krzysztof Jaskólski
    • Łukasz Marchel
    • Andrzej Felski
    • Marcin Jaskólski
    • Mariusz Specht
    2021 Pełny tekst SENSORS

    To enhance the safety of marine navigation, one needs to consider the involvement of the automatic identification system (AIS), an existing system designed for ship-to-ship and shipto- shore communication. Previous research on the quality of AIS parameters revealed problems that the system experiences with sensor data exchange. In coastal areas, littoral AIS does not meet the expectations of operational continuity and system availability, and there are areas not covered by the system. Therefore, in this study, process models were designed to simulate the tracking of vessel trajectories, enabling system failure detection based on integrity monitoring. Three methods for system integrity monitoring, through hypotheses testing with regard to differences between model output and actual simulated vessel positions, were implemented, i.e., a Global Positioning System (GPS) ship position model, Dead Reckoning and RADAR Extended Kalman Filter (EKF)—Simultaneous localization and mapping (SLAM) based on distance and bearing to navigational aid. The designed process models were validated on simulated AIS dynamic data, i.e., in a simulated experiment in the area of Gda´nsk Bay. The integrity of AIS information was determined using stochastic methods based on Markov chains. The research outcomes confirmed the usefulness of the proposed methods. The results of the research prove the high level (~99%) of integrity of the dynamic information of the AIS system for Dead Reckoning and the GPS process model, while the level of accuracy and integrity of the position varied depending on the distance to the navigation aid for the RADAR EKF-SLAM process model.

  • Automation of the Road Gate Operations Process at the Container Terminal—A Case Study of DCT Gdańsk SA
    • Karol Moszyk
    • Mariusz Deja
    • Michał Dobrzyński
    2021 Pełny tekst Sustainability

    The future increased terminal capacity will result in more container movement through the road complex and rail siding, which are one of the most critical areas (potential bottlenecks) in the container terminal. Truck turnaround time is one of the major factors that customers take into account while deciding how many container volumes they will handle through the container terminal. To enable to optimize increased traffic with future container terminal development, as well as increase gates throughput, and as a consequence, encourage more volume and increase customer satisfaction, Deepwater Container Terminal Gdańsk SA plans to reorganize and automatize Gate Operation Process. Gate Automation includes supply, installation, commissioning, implementation, and maintenance of software and hardware that would allow automatizing the handling of trucks at container terminal gates by using OCR (Optical Camera Recognition) technology, LPR (License Plate Recognition) systems and self-service kiosk for truck drivers.

  • AUTOMATYCZNE GENEROWANIE KOLEJNOŚCI LIST UTWORÓW MUZYCZNYCH
    • Kamila Pietrusińska
    • Adam Kurowski
    • Bożena Kostek
    2021

    W niniejszym rozdziale przedstawiono przygotowanie algorytmu do automa-tycznego układania kolejności utworów muzycznych i zgrywającego je do postaci jednego, długiego miksu. Dzięki algorytmowi dobierane są utwory na podstawie analizy podobieństwa fragmentów końcowych i początkowych utworów. Podo-bieństwo to jest obliczane za pomocą odległości euklidesowej między wektorami parametrów wyznaczonymi przez autoenkoder oraz na podstawie analizy skupień (data clustering). Taki sposób ułożenia utworów umożliwia zapewnienie ciągłości listy. Jakość wyników jest weryfikowana z zastosowaniem testów odsłuchowych przez porównanie automatycznie generowanych list z listami ułożonymi w sposób losowy.

  • Automatyzacja procesów produkcji spiekanych kompozytów diamentowo-metalowych.
    • Andrzej Bakoń
    • Adam Barylski
    2021 Materiały & Maszyny Technologiczne

    Przedstawiono technologie produkcji narzędzi diamentowych o spoiwach metalowych spiekanych. Na podstawie własnych doświadczeń oraz kontaktów z wytwórcami takich narzędzi i firmami oferującymi urządzenia do ich produkcji dokonano przeglądu stosowanych technologii wytwarzania pod katem ich automatyzacji.

  • Axial capacity of steel built-up battened columns
    • Paweł Pieczka
    • Piotr Iwicki
    2021

    This paper deals with the numerical investigation aimed to study the axial capacity of pin-ended steel built-up columns. Three methods of calculating forces in chords and batten, taking into account the material and geometric imperfections specified in the Eurocode 3 are considered. The aim of this study was to compare different methods allowing the calculation of the column load capacity and determine a simpler and faster method than the present Eurocode 3 procedure related to design of built up members. In the paper, the method according to Eurocode 3 for uniform built-up compression member and the method according to PN-B-03200:1990 are compared with the code method for the structure modeled as separate members for column chords and battens. Calculations were carried out for the column modeled by 1D-beam elements and for a whole shell model of the column. Finite element (FE) models were established and verified against the built-up columns with similar configurations that were tested experimentally in the studies presented in the literature, and then compared with the calculations specified in Eurocode 3.

  • Bacteriophages as potential tools for use in antimicrobial therapy and vaccine development
    • Beata Zalewska-Piątek
    • Rafał Piątek
    2021 Pełny tekst Pharmaceuticals

    The constantly growing number of people suffering from bacterial, viral, or fungal infections, parasitic diseases, and cancers prompts the search for innovative methods of disease prevention and treatment, especially based on vaccines and targeted therapy. An additional problem is the global threat to humanity resulting from the increasing resistance of bacteria to commonly used antibiotics. Conventional vaccines based on bacteria or viruses are common and are generally effective in preventing and controlling various infectious diseases in humans. However, there are problems with the stability of these vaccines, their transport, targeted delivery, safe use, and side effects. In this context, experimental phage therapy based on viruses replicating in bacterial cells currently offers a chance for a breakthrough in the treatment of bacterial infections. Phages are not infectious and pathogenic to eukaryotic cells and do not cause diseases in human body. Furthermore, bacterial viruses are sufficient immuno-stimulators with potential adjuvant abilities, easy to transport, and store. They can also be produced on a large scale with cost reduction. In recent years, they have also provided an ideal platform for the design and production of phage-based vaccines to induce protective host immune responses. The most promising in this group are phage-displayed vaccines, allowing for the display of immunogenic peptides or proteins on the phage surfaces, or phage DNA vaccines responsible for expression of target genes (encoding protective antigens) incorporated into the phage genome. Phage vaccines inducing the production of specific antibodies may in the future protect us against infectious diseases and constitute an effective immune tool to fight cancer. Moreover, personalized phage therapy can represent the greatest medical achievement that saves lives. This review demonstrates the latest advances and developments in the use of phage vaccines to prevent human infectious diseases; phage-based therapy, including clinical trials; and personalized treatment adapted to the patient’s needs and the type of bacterial infection. It highlights the advantages and disadvantages of experimental phage therapy and, at the same time, indicates its great potential in the treatment of various diseases, especially those resistant to commonly used antibiotics. All the analyses performed look at the rich history and development of phage therapy over the past 100 years.

  • Badania architektoniczne Twierdzy Wisłoujście w Gdańsku. Etap III: wnętrza Wieńca
    • Piotr Samól
    • Arkadiusz Woźniakowski
    • Robert Hirsch
    2021

    Badania architektoniczne dotyczyły Wieńca w Twierdzy Wisłoujście. Stanowiły uzupełnienie rozwarstwień Wieńca w zakresie planu budowli.

  • Badania nad docieraniem płaskich elementów ceramicznych z wymuszonym dawkowaniem zawiesiny ściernej
    • Adam Barylski
    • Maciej Gniot
    2021

    W pracy przedstawiono zagadnienia dotyczące obróbki wykończeniowej płaskich uszczelnień ceramicznych. Wymagania obróbkowe stawiane tego typu elementom sprawiają, że konieczne jest zastosowanie docierania w procesie technologicznym. Tego typu bardzo dokładna obróbka ścierna powierzchni płaskich wymaga użycia odpowiedniej zawiesiny lub pasty ściernej. Na wynik obróbki ma wpływ wiele czynników związanych z metalową tarczą docierającą, składnikami zawiesiny ściernej i warunkami technologicznymi obróbki. Decydujące znaczenie ma też sposób i intensywność dawkowania zawiesiny w strefę docierania. Standardowy swobodny sposób dawkowania - w sposób ciągły, najczęściej zalewowo lub kroplowo, powoduje duże straty ścierniwa. Część mikroziaren ściernych zostaje szybko usunięta z powierzchni roboczej tarczy docierającej przez obracające się pierścienie prowadzące separatory z obrabianymi elementami i nie bierze w ogóle udziału w skrawaniu. Opracowany innowacyjny układ jest przystosowany do pracy na docierarce Abralap 380. W artykule opisano zalety takiego systemu dawkowania zawiesiny ściernej oraz sposób postępowania podczas planowania badań docierania elementów płaskich z ceramiki technicznej na przykładzie Al2O3. Zaprezentowano wybrane wyniki badań ubytku elementów, które następnie poddano analizie statystycznej.

  • Badania skuteczności ochrony katodowej Nabrzeża Zachodniego odcinek nr 1 (południowy) oraz Pomostu A w Porcie Gdynia
    • Krzysztof Żakowski
    • Juliusz Orlikowski
    • Kazimierz Darowicki
    2021

    Zbadano skuteczność ochrony katodowej południowego odcinka nabrzeża zachodniego oraz pomostu A w Porcie Wojennym w Gdyni. Ochrona realizowana jest za pomocą aluminiowych anod galwanicznych spawanych do ścianki szczelnej oraz pali.

  • Badania skuteczności ochrony katodowej Nabrzeża Zachodniego odcinek nr 2 (północny) oraz Pirsu C w Porcie Gdynia
    • Krzysztof Żakowski
    • Juliusz Orlikowski
    • Kazimierz Darowicki
    2021

    Zbadano skuteczność ochrony katodowej północnego odcinka nabrzeża zachodniego oraz pomostu C w Porcie Wojennym w Gdyni. Ochrona realizowana jest za pomocą aluminiowych anod galwanicznych spawanych do ścianki szczelnej oraz pali.

  • Badania skuteczności ochrony katodowej Ostrogi Pilotowej w Porcie Gdynia
    • Krzysztof Żakowski
    • Kazimierz Darowicki
    2021

    Przedmiotem opracowania jest ocena skuteczności ochrony katodowej palościanki Ostrogi Pilotowej w Porcie Wojennym w Gdyni Oksywiu. Ochrona realizowana jest za pomocą aluminiowych anod galwanicznych spawanych do ścianki.

  • Badania wytrzymałościowe zgrzein łączących pręty zbrojeniowe o średnicy Ø30mm
    • Wojciech Kiełczyński
    • Ryszard Buza
    2021

    Zakres badań dotyczy oceny wytrzymałościowej zgrzein doczołowych, wykonanych metodą zwarciową. Elementami zgrzewanymi były pręty zbrojeniowe o średnicy Ø30mm. Badania związane są z okresową kontrolą stabilności parametrów zgrzewarki, szczególnie w odniesieniu do górnych, dopuszczalnych przez producenta zakresów parametrów zgrzewania oraz analizą wyników i porównaniu rezultatów prób wytrzymałościowych uzyskanych w 2019 i 2020 w trakcie wdrażania technologii.

  • BADANIE ZABEZPIECZEŃ MODUŁÓW WYTWARZANIA ENERGII ZGODNIE Z WYMAGANIAMI KODEKSU SIECI RfG
    • Mirosław Włas
    • Kacper Chyła
    2021 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Celem zapewnienia bezpieczeństwa systemu elektroenergetycznego w ramach systemu wzajemnie połączonego, niezbędnym jest ustalenie jednakowych wymogów mających zastosowanie do modułów wytwarzania energii. W tym celu ustanowiony został kodeks sieci RfG dotyczący wymogów w zakresie przyłączania jednostek wytwórczych do sieci. W pracy przedstawione zostały wymagania kodeksu sieci RfG wobec zabezpieczeń źródeł wytwórczych. Na stanowisku badawczym przeprowadzono próby działania zabezpieczeń z wykorzystaniem przekaźnika zabezpie-czeniowego REX 640 na modelu sieci oraz wykonana została komunikacja z nadrzędnym systemem SCADA wykorzystując protokół IEC 61850. Przeprowadzone badania są niezbędne do złożenia dokumentu PGMD zezwalającego na eksploatację modułu wytwarzania energii.

  • Badanie zdolności do odkształcenia plastycznego kątowych próbek spawanych o zmiennej geometrii połączenia i różnym wkładem ciepła (energii liniowej)
    • Wojciech Kiełczyński
    • Jacek Haras
    • Marek Chodnicki
    2021

    Przedmiotem badań były próbki dostarczone przez Zleceniodawcę wykonane w rożnych warunkach cieplnych i geometrycznych. W tej części pracy próbki poddano badaniom mającym stwierdzić ich zdolność do odkształceń plastycznych. 3. Przeprowadzone w tych samych warunkach próby badania zdolności spoin, a szczególnie grani do odkształcenia plastycznego ujawniły, że jakość połączeń zrealizowanych wg wariantu zmodyfikowanego jest wyższa niż w przypadku wariantu bez modyfikacji. Świadczą o tym badania wizualne rozciąganych powierzchni grani spoiny.

  • Bariery i ograniczenia wdrażania technologii BIM- wyniki badań pilotażowych
    • Waldemar Kosiedowski
    • Marek Wirkus
    2021 Pełny tekst Builder

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  • Bariery rozwoju bioekonomii w Polsce
    • Roksana Bochniak
    • Aleksandra Gołąbek
    • Paweł Dąbrowski
    • Dariusz Mikielewicz
    2021 Przegląd Komunalny

    W Polsce sytuacja ponownego wykorzystania odpadu celem produkcji nowych produktów nie jest obecnie do końca uregulowana prawnie. Nie obserwuje się wielu dobrych praktyk w przedsiębiorstwach. Wartościowe odpady poprodukcyjne są wykorzystywane na cele energetyczne bądź jako nawóz dla roślin lub pasza dla zwierząt. W celu zlokalizowania barier w rozwoju bioekonomii przeprowadzono wywiady z osobami bezpośrednio związanymi z kwestiami dotyczącymi tego zagadnienia.

  • Baseline-free debonding detection in reinforced concrete structures by elastic wave propagation
    • Beata Zima
    • Rafał Kędra
    2021 Pełny tekst MEASUREMENT

    The article presents the results of the numerical and experimental analysis concerning wave propagation in reinforced concrete (RC) beams with various extent of debonding between the steel rod and concrete cover. The main aim of the paper was to consider the unsolved research gaps, which considerably limit the application of wave-based methods in practice. The propagation of the flexural wave modes excited and registered on the outer surface of the concrete cover in RC beams with various damage sizes were considered. The phenomenon of flexural wave propagation in a damaged beam was described theoretically and the relationship between damage size and wave velocity was proposed. Next, the theoretical predictions were examined experimentally. The research allows to observe the variability of the velocity of a wave propagating in various regions of the monitored specimen. The differences between times of flight allow to determine the localization of the debonded rod. The study indicates that the debonding size can be successfully determined if the velocities of flexural wave modes in the concrete specimen as well as in separated reinforcing rod are known.

  • Baza polityk wydawniczych i repozytorium Open Access – uzupełniające się elementy
    • Joanna Błasiok
    • Agnieszka Szymik
    2021 Pełny tekst

    Przedstawiono korzyści płynące z tworzenia i wykorzystywania bazy polityk wydawniczych polskich czasopism naukowych dla różnych interesariuszy, takich jak wydawcy, redaktorzy, naukowcy i bibliotekarze. Omówiono podstawowe zadania i funkcje bazy, tak aby ukazać ją jako kompleksowe źródło informacji o polityce wydawniczej polskich czasopism. Gromadzone w bazie informacje stanowią istotną pomoc w ustalaniu zasad samoarchiwizacji publikacji w repozytoriach naukowych. Na przykładzie deponowania materiałów w repozytorium MOST Wiedzy opisano wykorzystanie bazy w praktyce.

  • Bead-on-Plate Underwater Wet Welding on S700MC Steel
    • Jacek Tomków
    • Aleksandra Świerczyńska
    • Michał Landowski
    • Adrian Wolski
    • Grzegorz Rogalski
    2021 Pełny tekst Advances in Science and Technology Research Journal

    The participation of high strength steels in marine and offshore structures is increasing, which makes it necessary to develop recommendations for underwater repair welding works. The article presents the results of bead-on-plate welded specimens made of S700MC high strength steel in underwater wet welding conditions by covered elec- trodes. Three specimens with heat input values in the range 0.91-1.05 kJ/mm were made. The specimens were sub- jected to visual, metallographic, macro- and microscopic tests as well as hardness measurements using the Vickers method. It was found that the higher heat input leads to formation of mixed bainite-martensite microstructure in the heat-affected zone (HAZ). Lower heat input value results in presence of martensite in HAZ. It was shown that in the scope of the performed tests, the maximum hardness of HAZ did not exceed the critical value for the material group, and the increase in heat input caused the decrease of hardness by about 25 HV10 to a level 250-260 HV10.

  • Bee Bread Exhibits Higher Antimicrobial Potential Compared to Bee Pollen
    • Karolina Pełka
    • Olga Otłowska
    • Randy Worobo
    • Piotr Szweda
    2021 Pełny tekst Antibiotics-Basel

    This study aimed at investigation of the antimicrobial potential of ethanolic extracts of bee bread (BB) and bee pollen (BP) and suspensions of these products in MHB (Mueller Hinton Broth). We covered 30 samples of BP and 19 samples of BB harvested in Polish apiaries. Slightly lower activity was observed against Gram-negative bacteria compared to Gram-positive staphylococci. BB extracts exhibited higher inhibitory potential with minimum inhibitory concentration (MIC) values in the range from 2.5 to 10% (v/v) against Staphylococcus aureus ATCC 25923 and ATCC 29213. Most active BB extracts, namely, BB6, BB11 and BB19, effectively inhibited growth of clinical isolates of S. aureus (n = 9), including MRSA (methicillin resistant Staphylococcus aureus) strains (n = 3) at concentrations ranging from 2.5 to 5.0% (v/v). Minimal bactericidal concentration (MBC) values were in the same range of concentrations; however, a shift from 2.5 to 5.0% (v/v) was observed for some products. The most active BP extracts inhibited the growth of reference strains of S. aureus at a concentration of 5% (v/v). Up to the concentration of 20% (v/v) three and seven BP extracts were not able to inhibit the growth of S. aureus ATCC 29213 and S. aureus ATCC 25923 respectively. The growth of staphylococci was also importantly inhibited in suspensions of the products in MHB. No correlation between phenolic content and antimicrobial activity was observed

  • Bee Pollen and Bee Bread as a Source of Bacteria Producing Antimicrobials
    • Karolina Pełka
    • Randy Worobo
    • Justyna Walkusz
    • Piotr Szweda
    2021 Pełny tekst Antibiotics-Basel

    The principal objective of the study was the isolation and identification of bacteria that are present in mature bee bread (BB) and dried (ready for selling and consumption) bee pollen (BP). Obtained isolates were screened for their potential to inhibit select human pathogenic bacteria and their ability to produce enzymes of particular industrial importance. Four and five samples of BP and BB, respectively, were used for the study. In total, 81 strains of bacteria were isolated, and 34 (42%) of them exhibited antagonistic interactions with at least one reference strain of pathogenic bacteria, namely Staphylococcus aureus ATCC 25923, Staphylococcus aureus ATCC 29213, Staphylococcus epidermidis 12228, Pseudomonas aeruginosa ATCC 27857, and Escherichia coli ATCC 25922. The sequencing of the 16S rRNA gene revealed that all strains producing antimicrobials belong to the genus Bacillus spp., and among them, five species were identified: B. pumilus (n = 17), B. altitudinis (n = 9), B. licheniformis (n = 4), B. subtilis (n = 2), and B. safensis (n = 1). Furthermore, 69, 54, 39, and 29 of the strains exhibited lipolytic, proteolytic, cellulolytic, and esterolytic activity, respectively. Alpha amylase and beta galactosidase activity were rarely observed, and none of the strains produced laccase. The outcomes of the study revealed that BP and BB can be considered potential sources of bacteria producing antimicrobial agents and/or enzymes of particular industrial importance. Of course, additional research is required to verify this hypothesis, but the results of preliminary studies are promising.

  • Behavior of residual current devices at frequencies up to 50 kHz
    • Stanisław Czapp
    • Hanan Tariq
    2021 Pełny tekst ENERGIES

    The use of residual current devices (RCDs) is obligatory in many types of low-voltage circuits. They are devices that ensure protection against electric shock in the case of indirect contact and may ensure additional protection in the case of direct contact. For the latter purpose of protection, only RCDs of a rated residual operating current not exceeding 30 mA are suitable. Unfortunately, modem current-using equipment supplied via electronic converters with a pulse width modulation produces earth fault currents composed of high-frequency components. Frequency of these components may have even several dozen kHz. Such components negatively influence the RCDs’ tripping level and, hence, protection against electric shock may be ineffective. This paper presents the results of the RCDs’ tripping test for frequencies up to 50 kHz. The results of the test have shown that many RCDs offered on the market are not able to trip for such frequencies. Such behavior was also noted for F-type and B-type RCDs which are recommended for the circuits of high-frequency components. Results of the test have been related to the requirements of the standards concerning RCDs operation. The conclusion is that these requirements are not sufficient nowadays and should be modified. Proposals for their modification are presented.

  • Benchmarking Scalability and Security Configuration Impact for A Distributed Sensors-Server IOT Use Case
    • Robert Kałaska
    • Paweł Czarnul
    2021 Pełny tekst

    Internet of Things has been getting more and more attention and found numerous practical applications. Especially important in this context are performance, security and ability to cope with failures. Especially crucial is to find good trade-off between these. In this article we present results of practical tests with multiple clients representing sensors sending notifications to an IoT middleware – DeviceHive. We investigate performance under different loads by various numbers of IoT clients and show how various strengths of the hash algorithm affect the performance measured by the number of client requests handled within a predefined time frame.

  • Betaine and L-carnitine ester bromides: Synthesis and comparative study of their thermal behaviour and surface activity
    • Angelica Mero
    • Andrea Mezzetta
    • Janusz Nowicki
    • Justyna Łuczak
    • Lorenzo Guazzelli
    2021 JOURNAL OF MOLECULAR LIQUIDS

    Six esters of both betaine and L-carnitine bromides, featuring alkyl groups ranging from C8 to C18 in length, have been synthesized. The thermal behaviour of these twelve bio-based salts has been analyzed and compared by thermal gravimetric analysis and differential scanning calorimetry. The L-carnitine alkyl ester bromides melted below 100 C and can hence be considered ionic liquids (ILs) with full rights. Conversely, the betaine alkyl ester bromides, with the exception of the shortest member of the series, melted slightly above this upper limit. Also, they resulted less thermally stable when compared to their L-carnitine analogues. Moreover, the self-aggregation behavior of these structurally related betaine and L-carnitine alkyl ester bromides, inspected through surface tension, conductivity measurements and isothermal titration calorimetry, varied significantly. The critical micelle concentration (CMC) values for the L-carnitine series were lower than those of the betaine series, and the former ILs were also capable of adsorbing more efficiently at the air/water interface as well as of reducing surface tension. A potential use of these organic salts as components of deep eutectic solvents is envisaged, thus showcasing the applicability of this natural trimethylammonium cation.

  • Beyond the helium buffer: 12C−2 rotational cooling in cold traps with H2 as a partner gas: interaction forces and quantum dynamics
    • Barry P. Mant
    • Jan Franz
    • Roland Wester
    • Francesco Antonio Gianturco
    2021 Pełny tekst MOLECULAR PHYSICS

    abstract = { The scattering cross-sections and corresponding rate coefficients for rotationally inelastic collisions of $^{12}$C$_2$^-$ ($^2 \Sigma_g^+$) with H$_2$ ($^1 \Sigma_g^+$) are presented over a broad range of cold-trap temperatures. They have been calculated using quantum scattering theory that employs a new ab initio potential energy surface. The rate coefficients for the inelastic processes in the anionic partner are used to model the thermalisation dynamics of $^{12}$C$_2$^-$ using H$_2$ as a buffer gas, a trap partner which is found here to be far more efficient than the typical buffer gas He and even more so than when using Ar as a partner gas. The microscopic physics underlying these findings is discussed in some detail. We additionally compute and discuss $^{12}$C$_2$^-$ quadrupole transitions by spontaneous emission and use the newly computed rates to show that the anion's rotational levels should be in local thermal equilibrium at typical interstellar conditions.

  • Bez tytułu, obraz olejny, 95x80 cm
    • Jan Buczkowski
    2021

    Prezentacja obrazu na wystawie sztuki współczesnej

  • Bezczujnikowe sterowanie pięciofazową maszyną indukcyjną klatkową zasilaną z falownika prądu
    • Filip Wilczyński
    2021 Pełny tekst

    W rozprawie podjęto temat bezczujnikowego sterowania pięciofazową maszyną indukcyjną zasilaną z falownika prądu. Autor rozprawy zaproponował nowe struktury regulacji dla pięciofazowej maszyny indukcyjnej zasilanej z falownika prądu (w podwójnym układzie współrzędnych), które umożliwiają lepsze wykorzystanie obwodu magnetycznego maszyny, poprzez kontrolowaną iniekcję trzeciej harmonicznej prądu. W rozprawie przedstawiono algorytmy wektorowej modulacji szerokości impulsów dla pięciofazowego falownika prądu, pozwalające na niezależne kształtowanie dwóch wektorów prądu wyjściowego falownika. Autor przedstawił wyniki badań symulacyjnych i eksperymentalnych opracowanych struktur regulacji oraz algorytmów modulacji szerokości impulsów. Ponadto, przedstawiono bezczujnikową pracę badanego układu napędowego oraz analizę uzyskanych przebiegów prądu i napięcia stojana pięciofazowej maszyny indukcyjnej zasilanej z falownika prądu.

  • Bias-Dependent Dynamics of Degradation and Recovery in Perovskite Solar Cells
    • M. Prete
    • M. V. Khenkin
    • Damian Głowienka
    • B. R. Patil
    • J. S. Lissau
    • Ilker Dogan
    • Jennie Hansen
    • T. Leißner
    • J. Fiutowski
    • H.-G. Rubahn
    • B. Julsgaard
    • P. Balling
    • V. Turkovic
    • Yulia Galagan
    • E. A. Katz
    • M. Madsen
    2021 Pełny tekst ACS Applied Energy Materials

    Degradation of perovskite solar cells (PSCs) is often found to be partially or fully reversible when the cells are allowed to recover in the dark. Unlike the dynamics of degradation, knowledge about the dynamics of PSC cell recovery is very limited. Here, we demonstrate that the PSC recovery strongly depends on the electrical bias conditions during the light-induced degradation and that it can be manipulated by applying an external electrical bias during the recovery phase. Investigation of the recovery dynamics allows us to analyze the degradation mechanisms in detail. More specifically, we aged a mixed-cation mixed-halide PSC with a n-i-p structure under illumination in open-circuit (OC) or short-circuit (SC) conditions, and periodically measured their characteristics during the recovery. PSCs aged in SC degrade faster and fully recover after the light is switched off, while the performance of the cells aged in OC does not recover but instead further decreases after the light is switched off (“drop-in-dark” effect). With the use of transient photoluminescence, secondary ion mass spectrometry, and drift-diffusion-based simulations, we hypothesize that extrinsic ion migration causes the drop-in-dark effect, by forming an electron extraction barrier at the metal oxide electron transport layer. The applied bias alleviates this effect. Our results are relevant for gaining a deeper understanding of the multiple degradation mechanisms present in perovskite solar cells, and for finding a practical way to assist their recovery.

  • Bicycle Traffic Model for Sustainable Urban Mobility Planning
    • Jacek Oskarbski
    • Krystian Birr
    • Karol Żarski
    2021 Pełny tekst ENERGIES

    Modelling tools and transport models are required to assess the impact of measures for the effective planning of cycling routes in cities. This paper presents the methodology for developing a four-stage macroscopic model of bicycle traffic for the city of Gdynia, and its use in planning new bicycle routes, considering a modal shift. The model presented in this paper allows for the evaluation of the influence of the characteristics of the cycling infrastructure, along with the development of the cycling network based on the choice of cycling as an alternative to other modes of transport, by taking into account the modal shift. The model takes into account the influence of the longitudinal gradient, link, and surface type of cycling routes on the distribution and demand for bicycle traffic. The results of our research allow us to assess the impact of planned cycling routes on the reduction in the volume of car traffic, which is crucial for reducing energy consumption and negative environmental impacts. Experiences from the application of the model in Gdynia suggest that the model provides a strong basis to support mobility planning and monitoring processes in cities worldwide. Cities should take into account the methods proposed in this paper when planning the development of their transport systems.

  • Bifractal receiver operating characteristic curves: a formula for generating receiver operating characteristic curves in credit-scoring contexts
    • Błażej Kochański
    2021 Pełny tekst Journal of Risk Model Validation

    This paper formulates a mathematical model for generating receiver operating characteristic (ROC) curves without underlying data. Credit scoring practitioners know that the Gini coefficient usually drops if it is only calculated on cases above the cutoff. This fact is not a mathematical necessity, however, as it is theoretically possible to get an ROC curve that keeps the same Gini coefficient no matter how big a share of lowest score cases are excluded from the calculation (a “right-hand” fractal ROC curve). Analogously, a left-hand fractal ROC curve would be a curve that keeps its Gini coefficient constant below any cutoff point. The model proposed here is a linear combination of left- and right-hand ROC curves. A bifractal ROC curve is drawn with just two parameters: one responsible for the shape of the curve and the other responsible for the area under the curve (a Gini coefficient). As is shown in this paper, most real-life credit-scoring ROC curves lie between the two fractal curves. In consequence, the Gini coefficient will be consistently lower when computed only on approved loans.

  • Bifurcation of equilibrium forms of a gas column rotating with constant speed around its axis of symmetry
    • Joanna Janczewska
    • Anita Zgorzelska
    2021 Pełny tekst NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS

    We will be concerned with the problem of deformation of the lateral surface of a column that rotates with constant speed around its axis of symmetry. The column is filled by a gas and our goal is to investigate the deformation of the lateral surface depending on the pressure of the gas.

  • Big Data from Sensor Network via Internet of Things to Edge Deep Learning for Smart City
    • Jerzy Balicki
    • Honorata Balicka
    • Piotr Dryja
    2021

    Data from a physical world is sampled by sensor networks, and then streams of Big Data are sent to cloud hosts to support decision making by deep learning software. In a smart city, some tasks may be assigned to smart devices of the Internet of Things for performing edge computing. Besides, a part of workload of calculations can be transferred to the cloud hosts. This paper proposes benchmarks for division tasks between an edge layer and a cloud layer for deep learning. Results of some numerical experiments are presented, too.

  • Bilans energii i ślad węglowy w zrównoważonej gospodarce oczyszczalni ścieków
    • Ewa Zaborowska
    • Mojtaba Maktabifard
    • Jacek Mąkinia
    2021 Forum Eksploatatora

    Dążenie do osiągnięcia zrównoważonego rozwoju stawia przed oczyszczalniami ścieków (OŚ) nowe wyzwania. Oprócz dotrzymywania standardów jakościowych w odpływie, obserwuje się dążenie do samowystarczalności energetycznej. Nowym kryterium oceny jest ślad węglowy (CF) określający skumulowaną emisję gazów cieplarnianych generowanych przez OŚ. Celem artykułu było określenie relacji między bilansem energii a śladem węglowym w zrównoważonej gospodarce miejskich OŚ. Dla sześciu obiektów wyznaczono całkowity CF i jego komponenty oraz zidentyfikowano wrażliwe parametry mogące wpływać na niepewność wyników. W artykule przedstawiono metodę uproszczoną bazującą na współczynnikach emisji oraz pokazano możliwości, jakie daje zastosowanie modelowania komputerowego. Stwierdzono, że zarówno emisje bezpośrednie, jak i pośrednie mogą istotnie wpływać na CF OŚ. Bezpośrednie emisje procesowe dominują w OŚ stosujących odzysk energii z biogazu (62-74%), a emisje pośrednie związane z energią dominują CF w OŚ pokrywających zapotrzebowanie z sieci elektroenergetycznej (69-72%). Wykazano, że wskaźniki procesowych emisji podtlenku azotu są specyficzne dla danego obiektu i należą do najbardziej wrażliwych parametrów wpływających na oszacowanie całkowitego CF. Nie stwierdzono występowania korelacji pomiędzy poziomem samowystarczalności energetycznej a całkowitym CF OŚ. Natomiast silna zależność wiąże samowystarczalność energetyczną ze stosunkiem pośredniej do bezpośredniej emisji gazów cieplarnianych. CF OŚ można obniżyć dzięki zastosowaniu odnawialnych źródeł energii i odzysku energii na miejscu, rolniczemu zagospodarowaniu osadów ściekowych, a także poprzez odpowiednią manipulację parametrów operacyjnych.