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  • A spline-based FE approach to modelling of high frequency dynamics of 1-D structures
    • Arkadiusz Żak
    • Wiktor Waszkowiak
    2021 Pełny tekst COMPUTERS & MATHEMATICS WITH APPLICATIONS

    In this paper a computational methodology leading to the development of a new class of FEs, based on the application of continuous and smooth approximation polynomials, being splines, has been presented. Application of the splines as appropriately defined piecewise elemental shape functions led the authors to the formulation of a new approach for FEM, named as spFEM, where contrary to the well-known NURBS approach, the boundaries of spFEs are well-defined, exactly as it is in the case of the traditional FEM. The current approach has been computationally verified by the authors it terms of high frequency dynamics including such problems as: spectra of natural frequencies, modes of natural vibrations as well as wave propagation problems, especially in the aspect of high frequency responses, all in the case of selected problems involving one- and two-mode theories of 1-D structural elements. The applicability of the proposed approach has been evaluated and compared, in terms of calculated dynamic responses, with the results obtained by the use of well-established FEM approaches: classical FEM as well as TD-SFEM. In all cases investigated by the authors the proposed spFEM approach turned out to be the most accurate approach, free from the main drawback of the other tested FEM approaches thanks to the class of differentiability of approximation polynomials, which guarantees the absence of frequency band gaps in calculated spectra of natural frequencies. A direct consequence of this feature of the proposed approach is that a larger part of the calculated spectra of natural frequency, the same as modes of natural vibrations, can effectively be used for more accurate calculations of dynamic reposes even in the case of multi-mode theories. This in contrast to the other tested FEM approaches.

  • A study about daylighting knowledge and education in Europe. Results from the first phase of the DAYKE project
    • Federica Giuliani
    • Natalia Sokół
    • Valerio R.M. Lo Verso
    • Raquel Viula
    • Federica Caffaro
    • Bernard Paule
    • Aicha Diakite
    • Yannick Sutter
    2021 Pełny tekst Architectural Science Review

    This paper presents selected results from the first stage of DAYKE (Daylight Knowledge in Europe), a 3- phase project that investigates the knowledge on daylighting in buildings among architecture students and practitioners across Europe. Subjective judgements from 561 students from 8 architecture universities in the EU, collected through two surveys in 2018. The key findings are: (i) the spatial distribution of comfort and mood in the classrooms varied depending on sky conditions and distance from windows; (ii) the average daylight factor DFm showed a good agreement with subjective judgements on the amount of daylight in a space; (iii) experts and non-experts provided similar judgements on the perception of a daylit environment; (iv) a general lack of knowledge about daylighting metrics, regulations, assessment tools and software was highlighted. Furthermore a difficulty in implementing daylighting into the design practice is also identified.

  • A study of jet impingement cooling enhancement by concave and convex heat sink shape modifications
    • Marcin Froissart
    • Paweł Ziółkowski
    • Janusz Badur
    2021 Pełny tekst E3S Web of Conferences

    The rising demand for efficient cooling technologies is a strong driver of extensive research in this area. This trend is particularly strong in turbines and microprocessors technology. Presented study is focused on the jet impingement cooling concept, which is used in various configurations for many years. The potential of the heat sink shape modification is not yet fully explored. Available literature suggests that average Nusselt number can be improved by more than 10% by adding conical shape in the stagnation region. This refers to the axisymmetric case where cold-water jet impinges the surface of heated aluminium. Presented results are based on 2D axisymmetric thermal-FSI (Fluid-Solid Interaction) model, which was validated against the experiment. The objective of the presented analysis is to determine the correlation between cooling effectiveness (Nusselt number) and chosen examples of concave and convex shapes located in the jet stagnation area.

  • A study on diagnosing both isotropic and orthotropic, intentionally damaged laminates
    • Khadijeh Askaripour
    • Arkadiusz Żak
    2021 Nondestructive Testing and Evaluation

    Being the most detrimental mode in laminated structures, delamination initially degrades local structural strength, and lastly causes global structural failure, thus necessitating delamination identification at its incipient stages. For identification purposes, a comprehensive numerical and experimental study on delamination within both the laminated isotropic acrylic-glass and orthotropic epoxyglass plates is presented. As the first step, frequency variations in the acrylic-glass plate induced by different-sized delamination are examined at varying the in-plane or out-of-plane location as well as boundary conditions of delamination. Tiny delamination is identified by the use of processed signals of Lamb wave simulated by spectral finite element (SFE) technique in the next step when noticing the delamination-induced changes of frequency to be inefficient for detection purposes. While utilising absorbing layers with the obtained mechanical properties along the axis of symmetry, a quarter of the plate in the SFE domain is modelled. The study is concluded with finding the accurate location and shape of small delamination using A0 or S0 modes. The preference of A0 mode for the delamination identification compared to S0 mode is indicated. Finally, for verification purposes of Lamb wave patterns in real-life applications, a composite epoxy-glass plate is experimentally investigated via laser Doppler vibrometer (LDV).

  • A Survey of Fast-Recovery Mechanisms in Packet-Switched Networks
    • Marco Chiesa
    • Andrzej Kamisinski
    • Jacek Rak
    • Gabor Retvari
    • Stefan Schmid
    2021 Pełny tekst IEEE Communications Surveys and Tutorials

    In order to meet their stringent dependability requirements, most modern packet-switched communication networks support fast-recovery mechanisms in the data plane. While reactions to failures in the data plane can be significantly faster compared to control plane mechanisms, implementing fast recovery in the data plane is challenging, and has recently received much attention in the literature. This survey presents a systematic, tutorial-like overview of packet-based fast-recovery mechanisms in the data plane, focusing on concepts but structured around different networking technologies, from traditional link-layer and IP-based mechanisms, over BGP and MPLS to emerging software-defined networks and programmable data planes. We examine the evolution of fast-recovery standards and mechanisms over time, and identify and discuss the fundamental principles and algorithms underlying different mechanisms. We then present a taxonomy of the state of the art, summarize the main lessons learned, and propose a few concrete future directions.

  • A Systematic Literature Review on Implementing Non-functional Requirements in Agile Software Development: Issues and Facilitating Practices
    • Aleksander Jarzębowicz
    • Paweł Weichbroth
    2021 Pełny tekst Lecture Notes in Business Information Processing

    Agile Software Development methods have become a widespread approach used by the software industry. Non-functional requirements (NFRs) are often reported to be a problematic issue for such methods. We aimed to identify (within the context of Agile projects): (1) the issues (challenges and problems) reported as affecting the implementation of NFRs; and (2) practices that facilitate the successful implementation of NFRs. We conducted a systematic literature review and processed its results to obtain a comprehensive summary. We were able to present two lists, dedicated to issues and practices, respectively. Most items from both lists, but not all, are related to the requirements engineering area. We found out that the issues reported are mostly related to the common themes of: NFR documentation techniques, NFR traceability, elicitation and communication activities. The facilitating practices mostly cover similar topics and the recommendation is to start focusing on NFRs early in the project.

  • A technique of experiment aided virtual prototyping to obtain the best spindle speed during face milling of large-size structures
    • Krzysztof Kaliński
    • Marek Galewski
    • Michał Mazur
    • Natalia Morawska
    2021 Pełny tekst MECCANICA

    The paper presents an original method concerning vibration suppression problem during milling of large-size and geometrically complicated workpieces with the use of novel way of selecting the spindle speed. This consists in repetitive simulations of the cutting process for subsequent values of the spindle speed, until the best vibration state of the workpiece is reached. An appropriate method of obtaining a computational model, called a modal approach, consists in identifying the parameters of the workpiece model created using the Finite Element Method (FEM). Thanks to the results of the identification of the modal subsystem obtained by the Experimental Modal Analysis (EMA) method, it can be stated that the parameters obtained from the experiment and delivered from the computational model have been correctly determined and constitute reliable process data for the simulation tests. The Root Mean Square (RMS) values of time domain displacements are evaluated. The efficiency of the proposed approach is evidenced by chosen technique of mechatronic design, called Experiment Aided Virtual Prototyping (EAVP). The proposed method is verified on the basis of the results of the experimental research of the relevant milling process.

  • A Universal Gains Selection Method for Speed Observers of Induction Machine
    • Daniel Wachowiak
    2021 Pełny tekst ENERGIES

    Properties of state observers depend on proper gains selection. Each method of state estimation may require the implementation of specific techniques of finding those gains. The aim of this study is to propose a universal method of automatic gains selection and perform its verification on an induction machine speed observer. The method utilizes a genetic algorithm with fitness function which is directly based on the impulse response of the observer. System identification using least-squares estimation is implemented to determine the dynamic properties of the observer based on the estimation error signal. The influence of sampling time as well as signal length on the system identification has been studied. The results of gains selection using the proposed method have been compared with results obtained using the approach based on the placement of the poles of linearized estimation error equations. The introduced method delivers results comparable with analytical methods and does not require prior preparation specific to the implemented speed observer, such as linearization.

  • A variational approach of homogenization of piezoelectric composites towards piezoelectric and flexoelectric effective media
    • Nagham Mawassy
    • Hilal Reda
    • Jean-François Ganghoffer
    • Victor Eremeev
    • Hassan Lakiss
    2021 Pełny tekst INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE

    The effective piezoelectric properties of heterogeneous materials are evaluated in the context of periodic homogenization, whereby a variational formulation is developed, articulated with the extended Hill macrohomogeneity condition. The entire set of homogenized piezoelectric moduli is obtained as the volumetric averages of the microscopic properties of the individual constituents weighted by the displacement and polarization localization operators. This framework is extended in a second part of the paper to the computation of the flexoelectric effective properties, thereby accounting for higher gradient effects that may be induced by a strong contrast of properties of the composite constituents. The effective properties of inclusion-based composites are evaluated numerically as an illustration of the general homogenization theory and the respective effect of the volume fraction and relative tensile modulus of the reinforcement is assessed numerically.

  • A Wideband Channel Model for Body Area Networks in Circular Metallic Indoor Environments
    • Filipe D. Cardoso
    • Manuel M. Ferreira
    • Sławomir Ambroziak
    • Luis M. Correia
    2021 Pełny tekst IEEE Access

    In this paper, the wideband characterization of the propagation channel in circular metallic indoor environments is addressed, regarding Body Area Networks and 5G small cells, an analytical model for the dependence of the mean delay and the average delay spread on the circle radius, the working frequency and the distance between the transmitter and the receiver being proposed. The derivation of the model is initially done analytically, based on optical physics, after which simulation results allow to obtain the values of the coefficients. The simulator was previously assessed with measurements at 2.45 GHz in a passenger ferry room with a circular shape. For a random positioning of the transmitter and the receiver, and a given distance between them, it is observed that the mean delay and the delay spread increase linearly with the radius; furthermore, the mean delay increases quadratically with the distance, while the delay spread has a concave parabolic behavior, with the maximum being at a distance equal to the radius. In a practical case, regarding the positioning of an Access Point inside the room, it is recommended that it is done at the circle center, in order to reduce delay spread.

  • A wireless network for off-shore marine research
    • Krzysztof Gierłowski
    • Michał Hoeft
    • Marcin Wichorowski
    2021 Bollettino di Geofisica Teorica ed Applicata

    This paper presents functionality, the most important technology developments and potential use cases of digital communication system, developed to facilitate selected tasks commonly required during off-shore operations and marine research, including: broadband information sharing between platforms isolated from an on-shore communication infrastructure, acquisition of large data-sets from variety of off-shore data sources (e.g. fleet of drones) as well as remote access and control to the research infrastructure exploited in environment with limited communication between neighboring devices.

  • Abilities, Motivations, and Opportunities of Furloughed Employees in the Context of Covid-19: Preliminary Evidence From the UK
    • Joanna Szulc
    • Rachael Smith
    2021 Pełny tekst Frontiers in Psychology

    The Covid-19 global pandemic is a crisis like no other, forcing governments to implement prolonged national lockdowns in an effort to limit the spread of the disease. As organizations aim to adapt and remain operational, employers can suspend or reduce work activity for events related to Covid-19 and claim government support to subsidize employee wages. In this way, some employees are placed on furlough (i.e., temporary unemployment) as opposed to being made redundant. While the impact of such schemes on global economy attracted much attention, their micro-level impact on individual employees is still unknown. Building on the ability-motivation-opportunity (AMO) framework, this pilot study explores how employees' perceptions of abilities, motivation, and opportunities are affected as a result of furlough. Rapid ethnography including interviews, observations, and document analysis in a British organization provided insights into the perceptions and experiences of employees put on furlough and highlighted that all three elements of AMO are affected by the current situation, either positively or negatively. We identify theoretical contributions and suggest a number of AMO enhancing practices in the context of furlough.

  • Accelerated Gradient-Based Optimization of Antenna Structures Using Multi-Fidelity Simulations and Convergence-Based Model Management Scheme
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2021 Pełny tekst IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    The importance of numerical optimization has been steadily growing in the design of contemporary antenna structures. The primary reason is the increasing complexity of antenna topologies, [ a typically large number of adjustable parameters that have to be simultaneously tuned. Design closure is no longer possible using traditional methods, including theoretical models or supervised parameter sweeping. To ensure reliability, optimization is normally carried out at the level of full-wave electromagnetic (EM) simulations, which incurs major computational expenses. The issue can be alleviated using a variety of methods such as the incorporation of adjoint sensitivities, sparse sensitivity updates (for local optimization), or the employment of surrogate modeling methods (in the context of global search). Another possibility is utilization of variable-fidelity simulation models, which, in practice, is most often restricted to two levels (coarse/fine or low-/high-fidelity models), and accompanied by appropriate low-fidelity model correction (e.g., space mapping). This paper proposes an accelerated version of a trust-region gradient-based procedure, which involves simulation model management by continuous adjustment of EM analysis fidelity throughout the optimization process. Decision making process is based on the convergence status of the algorithm. The initial stages of the optimization run are executed using the coarsest discretization of the structure at hand with the model being gradually refined towards the end of the process. This enables considerable computational savings without degrading the quality of the final design. The presented approach has been comprehensively validated using a benchmark set of four broadband antennas and compared to the reference trust-region procedure and two state-of-the-art accelerated algorithms. The average computational savings are almost sixty percent as compared to the reference.

  • Accelerated large scale test set-up design in natural corrosion marine environment
    • Krzysztof Wołoszyk
    • Yordan Garbatov
    2021

    The standards for conducting small-scale specimen tests are well developed, but there is a lack of direct guidelines for conducting corrosion tests for large-scale specimens. The objective here is to develop a methodology which may be used in designing an accelerated corrosion test of large-scale structural components subjected to a natural corrosion marine environment. Different factors influencing corrosion degradation of steel structures are analysed, including salinity and pH of the water, water velocity, oxygen content etc. The most important governing factors of corrosion degradation are identified, and the process of corrosion testing is defined in order to produce accelerated corrosion degradation in relatively short interval of time, developing a natural corrosion degradation mechanism, leading to irregular random corroded surfaces and material properties changes. Existing commercial testing equipment, that can be employed in creating accelerated corrosion conditions for testing large scale specimens, are investigated and the most efficient salt corrosion testing tank is identified. Several features of the corrosion test set-up are discussed.

  • Accumulation of volatile constituents in agar and bioreactor shoot cultures of Verbena officinalis L.
    • Adam Kokotkiewicz
    • Bożena Zabiegała
    • Pawel Kubica
    • Agnieszka Szopa
    • Adam Bucinski
    • Halina Ekiert
    • Maria Luczkiewicz
    2021 PLANT CELL TISSUE AND ORGAN CULTURE

    In vitro shoot cultures of common vervain (Verbena officinalis L., Verbenaceae) were established and evaluated for essential oil content. The shoots were maintained as stationary microshoot culture, grown on Schenk–Hildebrandt medium supplemented with 9.84 µM of 2-isopentenyladenine and 1.0 µM of thidiazuron. The shoots were further adapted to grow in two temporary immersion bioreactors (RITA and Plantform), using Schenk–Hildebrandt medium supplemented with 4.92 µM indole-3-butyric acid. The best growth, in terms of dry weight production, was recorded for agar culture (0.73 g l−1 day−1), followed by 35 days (day) Plantform (0.53 g l−1 day−1), 35 days RITA (0.42 g l−1 day−1) and 56 days Plantform culture (0.29 g l−1 day−1). The volatile fractions were obtained by simultaneous hydrodistillation-extraction of the plant materials using Likens–Nickerson apparatus. Aerial parts of V. officinalis intact plant and 56 d Plantform culture had the highest essential oil content (8.1 g kg−1) whereas the stationary agar culture excelled in essential oil productivity (5.0 mg l−1 day−1). The volatile oils isolated from in vitro shoots contained 1-octen-3-ol, benzyl alcohol, phenethyl alcohol, coumaran and hexadecenoic acid as major constituents. 1-Octen-3-ol was the predominant (> 50%) constituent of 35 day shoot cultures maintained in temporary immersion bioreactors whereas coumaran (19%) and hexadecanoid acid (21%) prevailed in stationary microshoot culture. The volatile fraction obtained from aerial parts of V. officinalis intact plant was composed mainly of hexadecanoic acid (> 20%), linalool (> 8%), anethole (> 5%) and carvone (> 3%).

  • Accuracy of Pretreatment Ultrasonography Assessment of Intra-Abdominal Spread in Epithelial Ovarian Cancer: A Prospective Study
    • Agnieszka Tomasińska
    • Maciej Stukan
    • Michał Badocha
    • Aleksandra Myszewska
    2021 Pełny tekst Diagnostics

    The aim of this study was to test the accuracy of ultrasonography performed by gynecological oncologists for the preoperative assessment of epithelial ovarian cancer (EOC) spread in the pelvis and abdominal cavity. A prospective, observational cohort study was performed at a single tertiary cancer care unit. Patients with suspected EOC were recruited and underwent comprehensive transvaginal and abdominal ultrasonography performed by a gynecological oncologist. Sixteen intra-abdominal localizations and parameters were assessed using ultrasonography and compared with surgical-pathological status (reference standard). Sensitivity, specificity, positive and negative predictive values, and overall accuracy were calculated. Differences were analyzed using Fisher’s exact and chi-square tests. Ultimately, we included 132 patients (median age 62 years), of whom 67% were in stage IIIC–IVB and 72% had serous cancer. Overall prediction accuracies for the involvement of the omentum, small bowel mesentery root, and frozen pelvis, and detecting ascites were >90%. Detecting the involvement of the pelvis peritoneum, liver and spleen hilum, and rectosigmoid colon, and predictions of disease stage and residual disease had overall accuracies of 80–90%. The lowest accuracy was for involvement of the abdominal peritoneum (69%) and diaphragm peritoneum (right 71%; left 75%) and surgical complexity prediction (77%). Stratification of results by presence or absence of ascites revealed significantly higher specificity of ultrasonography (clinically meaningful) for assessments of the abdominal/pelvic peritoneum, spleen hilum, and rectum wall, if there were ascites. A gynecological oncologist, experienced in surgery and sonology, performing comprehensive ultrasonography on patients with EOC can accurately detect intraperitoneal lesions and recognize critical disease manifestations and predict stage, surgical complexity, and residual disease, which allow accurate qualification of patients for primary debulking surgery or neoadjuvant chemotherapy.

  • Accurate Modeling of Frequency Selective Surfaces Using Fully-Connected Regression Model with Automated Architecture Determination and Parameter Selection Based on Bayesian Optimization
    • Nurullah Calik
    • Mehmet Belen
    • Peyman Mahouti
    • Sławomir Kozieł
    2021 Pełny tekst IEEE Access

    Surrogate modeling has become an important tool in the design of high-frequency structures. Although full-wave electromagnetic (EM) simulation tools provide an accurate account for the circuit characteristics and performance, they entail considerable computational expenditures. Replacing EM analysis by fast surrogates provides a way to accelerate the design procedures. Unfortunately, modeling of microwave passives is a challenging task due to their highly-nonlinear outputs. Frequency selective surfaces (FSSs) constitute a representative example with their multi-resonant reflection and transmission responses that need to be represented over broad frequency ranges. Deep neural networks (DNNs) seem to be the promising techniques for handling such cases. However, a serious practical issue associated with their employment is an appropriate selection of the model parameters, including its architecture. A common practice is experience-driven setup, heavily based on trial and error, which does not guarantee the optimum model determination and may lead to multiple problems such as poor generalization or high variance of the model predictive power with respect to the training data set selection. This paper proposes a novel modeling framework, referred to as a fully-connected regression model (FCRM), where the crucial role is played by Bayesian Optimization (BO), incorporated to determine the DNN-based model setup, including both its architecture and the hyperparameter values, in a fully automated manner. For validation, FCRM is applied to construct the model of a Minkowski Fractal-Based FSS. The efficacy of the methodology is demonstrated through comparisons with several benchmark techniques, including the DNN surrogates established using the traditional methods as well as conventional regression models. The numerical results indicate that FCRM exhibits considerably improved prediction power and reduced sensitivity to the training sample assignment.

  • Achieving Efficient and Stable Deammonification at Low Temperatures—Experimental and Modeling Studies
    • Hussein Al-Hazmi
    • Xi Lu
    • Dominika Grubba
    • Joanna Majtacz
    • Przemysław Kowal
    • Jacek Mąkinia
    2021 Pełny tekst ENERGIES

    The short-term effects of temperature on deammonification sludge were evaluated in a laboratory-scale sequencing batch reactor (SBR). Mathematical modeling was used for further evaluations of different intermittent aeration strategies for achieving high and stable deammonification performance at decreasing temperatures. As for the biomass cultivated at high temperatures (e.g., 30 C), a higher temperature dependency (the adjusted Arrhenius coefficient for 11–17 C = 1.71 vs. for 17–30 C = 1.12) on the specific anammox growth rates was found at lower temperatures (11–17 C) in comparison with higher temperatures (17–30 C). Further evaluations of recovering the nitrogen removal efficiency at decreasing temperatures with the mathematical model by modifying the intermittent aeration strategies (aeration frequency (F) and the ratio (R) between non-aerated (non-aer) phase and aerated (aer) phase durations) indicated that intermittent aeration with a prolonged non-aerated phase (e.g., R 4 regardless of F value) would help to maintain high and stable deammonification performance (~80%) at decreasing temperatures (14–22 C). Extending the non-aerated phases (increasing R) and reducing the frequency (F) of off/on phase changes have a positive effect on increasing energy savings, leading to increasing interest in this method.

  • Acid Rider. Idea „komunizmu kwasowego” Marka Fishera a doświadczenie zewnętrzności
    • Andrzej Karalus
    2021 Pełny tekst Praktyka Teoretyczna

    Acid communism pozostaje intrygującym wstępem Marka Fishera do planowanej przezeń historycznej rekonstrukcji radykalnych projektów politycznych wyrosłych na gruncie kultury psychodelicznej. Idea ta nie narodziła się w próżni, lecz stanowi konsekwencję jego poszukiwań teoretycznych. Artykuł próbuje osadzić koncepcję „komunizmu kwasowego” w szerszym kontekście, skupiając się na refleksji poświęconej doświadczeniu psychodelicznemu jako kontakcie z Zewnętrzem. Twierdzę, że istnieje zbieżność między koncepcją komunizmu kwasowego a zagadnieniami poruszanym przez Fishera w książce The Weird And The Eerie, gdzie analizuje potencjalnie transformujący szok zetknięcia z tym, co radykalnie Inne. Omówię przy tym krótko dwa fenomeny muzyczno-kulturowe, które zaistniały już po epoce psychodelii lat sześćdziesiątych. Posłużą one za egzemplifikacje trybów weird oraz eerie, obietnic przyszłości pokapitalistycznej, które nie znalazły politycznej reprezentacji i osunęły się na poziom widma niezrealizowanej przyszłości modernizmu. W końcowej części artykułu spróbuję pokazać jak zagadnienie komunizmu kwasowego wiąże się z kwestią pragnienia postkapitalistycznego oraz z Fisherowską wersją futuro-akceleracjonizmu.

  • Acoustic Detector of Road Vehicles Based on Sound Intensity
    • Grzegorz Szwoch
    • Józef Kotus
    2021 Pełny tekst SENSORS

    A method of detecting and counting road vehicles using an acoustic sensor placed by the road is presented. The sensor measures sound intensity in two directions: parallel and perpendicular to the road. The sound intensity analysis performs acoustic event detection. A normalized position of the sound source is tracked and used to determine if the detected event is related to a moving vehicle and to establish the direction of movement. The algorithm was tested on a continuous 24-h recording made in real-world conditions. The overall results were: recall 0.95, precision 0.95, F-score 0.95. In the analysis of one-hour slots, the worst results obtained in dense traffic were: recall 0.9, precision 0.93, F-score 0.91. The proposed method is intended for application in a network of traffic monitoring sensors, such as a smart city system. Its advantages include using a small, low cost and passive sensor, low algorithm complexity, and satisfactory detection accuracy

  • Acoustic Sensing Analytics Applied to Speech in Reverberation Conditions
    • Piotr Odya
    • Józef Kotus
    • Adam Kurowski
    • Bożena Kostek
    2021 Pełny tekst SENSORS

    The paper aims to discuss a case study of sensing analytics and technology in acoustics when applied to reverberation conditions. Reverberation is one of the issues that makes speech in indoor spaces challenging to understand. This problem is particularly critical in large spaces with few absorbing or diffusing surfaces. One of the natural remedies to improve speech intelligibility in such conditions may be achieved through speaking slowly. It is possible to use algorithms that reduce the rate of speech (RoS) in real time. Therefore, the study aims to find recommended values of RoS in the context of STI (speech transmission index) in different acoustic environments. In the experiments, speech intelligibility for six impulse responses recorded in spaces with different STIs is investigated using a sentence test (for the Polish language). Fifteen subjects with normal hearing participated in these tests. The results of the analytical analysis enabled us to propose a curve specifying the maximum RoS values translating into understandable speech under given acoustic conditions. This curve can be used in speech processing control technology as well as compressive reverse acoustic sensing.

  • Action Plan “Women”
    • Marzena Grzesiak
    • Anita Richert-Kaźmierska
    2021

    Employees of a company are not the first alternative coming into one’s mind when searching suitable successor for the business. Those belonging to the company’s management group are in many cases asked for their interest in being a successor, but the lower level an employee is in the hierarchy, the less probably he/she is inquired of his/her interest in becoming a successor. The contemporary entrepreneur may have had conflicts with employees, he may underestimate their capacities or there might be suspects concerning their loyalty to the company. On the other hand, it can be also difficult for an employee to express his interests in acquiring the business. The social pressure against the colleague wishing to start a trip across the classes, i.e. from worker to capitalist, may be, epending to the country, area and culture, crushing. An employee’s own family may be very critic against plans like that too. Nevertheless, many aspects are in favor of employees as considerable successors. In this chapter, these will be further discussed.

  • Activation of endogenous regenerative potential in mammals using epigenetic inhibitor zebularine
    • Piotr Sass
    2021

    In this work, a nucleoside inhibitor of DNA methyltransferases, zebularine, was investigated as a wound healing and regeneration promoting agent. It was found that a high dose of intraperitoneally delivered zebularine improved punch wound closure in the ear pinna in mice. Both cytidine, a zebularine analogue, and uridine, a zebularine metabolite, did not promote ear pinna hole closure. The effect of zebularine on ear pinna healing was dose-dependent. Further experiments showed that zebularine administration should be carried out shortly after the injury as several-day delays resulted in decreased effectiveness. Transcriptional activity of genes related to stem cell development and maintenance and cell cycle progression regulation was evaluated in the ear pinna tissues regenerating in response to zebularine treatment. Two of the crucial cell pluripotency genes, Nanog and Sox2, were remarkably induced in zebularine-treated ear pinnae on day 7 after injury. Also, the Cdkn2a gene encoding an inhibitor of a cell cycle progression was significantly upregulated in zebularine-treated pinnae. These findings suggest that zebularine enhances wound repair by activating genes that are silenced in adult tissues in normal conditions. Preliminary trials to translate the zebularine regenerative therapy to other injury models were performed. Topically delivered zebularine moderately accelerated dorsal skin wound healing in mice and positively affected the tissue architecture in the restored skin. This observation suggests that zebularine might drive skin repair into a regenerative response. Besides, a pilot experiment was carried out to evaluate the zebularine treatment effect on sciatic nerve healing following a crush-injury. To my knowledge, the zebularine-induced ear pinna regeneration is the first example of regenerating a complex tissue by use of an epigenetic inhibitor in vivo. These findings indicate that epigenetic modulation might become an essential step in regenerative therapies.

  • Active Annotation in Evaluating the Credibility of Web-Based Medical Information: Guidelines for Creating Training Data Sets for Machine Learning
    • Aleksandra Nabożny
    • Bartłomiej Balcerzak
    • Adam Wierzbicki
    • Mikołaj Morzy
    • Małgorzata Chlabicz
    2021 Pełny tekst JMIR Medical Informatics

    Methods Results Discussion References Abbreviations Copyright Abstract Background: The spread of false medical information on the web is rapidly accelerating. Establishing the credibility of web-based medical information has become a pressing necessity. Machine learning offers a solution that, when properly deployed, can be an effective tool in fighting medical misinformation on the web. Objective: The aim of this study is to present a comprehensive framework for designing and curating machine learning training data sets for web-based medical information credibility assessment. We show how to construct the annotation process. Our main objective is to support researchers from the medical and computer science communities. We offer guidelines on the preparation of data sets for machine learning models that can fight medical misinformation. Methods: We begin by providing the annotation protocol for medical experts involved in medical sentence credibility evaluation. The protocol is based on a qualitative study of our experimental data. To address the problem of insufficient initial labels, we propose a preprocessing pipeline for the batch of sentences to be assessed. It consists of representation learning, clustering, and reranking. We call this process active annotation. Results: We collected more than 10,000 annotations of statements related to selected medical subjects (psychiatry, cholesterol, autism, antibiotics, vaccines, steroids, birth methods, and food allergy testing) for less than US $7000 by employing 9 highly qualified annotators (certified medical professionals), and we release this data set to the general public. We developed an active annotation framework for more efficient annotation of noncredible medical statements. The application of qualitative analysis resulted in a better annotation protocol for our future efforts in data set creation. Conclusions: The results of the qualitative analysis support our claims of the efficacy of the presented method.

  • Active Suppression of Nonstationary Narrowband Acoustic Disturbances
    • Maciej Niedźwiecki
    • Michał Meller
    2021 Pełny tekst

    In this chapter, a new approach to active narrowband noise control is presented. Narrowband acoustic noise may be generated, among others, by rotating parts of electro-mechanical devices, such as motors, turbines, compressors, or fans. Active noise control involves the generation of “antinoise”, i.e., the generation of a sound that has the same amplitude, but the opposite phase, as the unwanted noise, which causes them to interfere destructively, rather than constructively. In the range of low frequencies (below 1 kHz), the active approach is more effective than passive methods that employ dampers, barriers, absorbers, and other forms of acoustic isolation.

  • Ad hoc prayer spaces – a challenge of the architecture of the 21th century
    • Agnieszka Szuta
    2021 Pełny tekst Studia oecumenica

    This article considers the problem of arranging places of prayer in the vicinity of universities and dormitories. A survey was conducted among students living in the dormitories of the Gdańsk University of Technology in order to determine if there was a real need to arrange such spaces. Subsequently, examples of temporary chapels designed in the last 20 years in Western European countries were presented. Analysis of the selected facilities and discussions based on literature studies made it possible to draw conclusions on the possibilities and ways of shaping temporary prayer spaces in the often historic and crowded university environments. The research included in situ investigations.

  • Adaptation of Architectural Heritage in the Era of Climate Change. Torpedo Platform in Babie Doły
    • Agnieszka Nyka
    • Jakub Szczepański
    2021

    The paper provides original insight into the problem of adap¬tation of historical objects in the era of climate change. It conveys a message that in times of climate crisis, there is a need to go beyond an anthropocentric perspective, specifically, that architec¬ture should not only be designed for people, but should also provide a framework for nature. As well as shaping spaces for human beings, the architect is also responsible for creating conditions for ecosys¬tem recovery and species protection. To illustrate this problem and as a critical reflection, the stunning example of the architecture of destruction was chosen – that is, the torpedo platform in Babie Doły built during WWII on the waters of Gdańsk Bay. The present¬ed project is a discussion on how to change this place of destruction into a place of both social and ecological regeneration, a laboratory that demonstrates, from a broader perspective, the opportunity of renaturalisation of urban areas through architecture.

  • Adaptive Method for Modeling of Temporal Dependencies between Fields of Vision in Multi-Camera Surveillance Systems
    • Karol Lisowski
    • Andrzej Czyżewski
    2021 Pełny tekst Electronics

    A method of modeling the time of object transition between given pairs of cameras based on the Gaussian Mixture Model (GMM) is proposed in this article. Temporal dependencies modeling is a part of object re-identification based on the multi-camera experimental framework. The previously utilized Expectation-Maximization (EM) approach, requiring setting the number of mixtures arbitrarily as an input parameter, was extended with the algorithm that automatically adapts the model to statistical data. The probabilistic model was obtained by matching to the histogram of transition times between a particular pair of cameras. The proposed matching procedure uses a modified particle swarm optimization (mPSO). A way of using models of transition time in object re-identification is also presented. Experiments with the proposed method of modeling the transition time were carried out, and a comparison between previous and novel approach results are also presented, revealing that added swarms approximate normalized histograms very effectively. Moreover, the proposed swarm-based algorithm allows for modelling the same statistical data with a lower number of summands in GMM.

  • ADAPTIVE METHOD FOR THE SOLUTION OF 1D AND 2D ADVECTION-DIFFUSION EQUATIONS USED IN ENVIRONMENTAL ENGINEERING
    • Romuald Szymkiewicz
    • Dariusz Gąsiorowski
    2021 Pełny tekst JOURNAL OF HYDROINFORMATICS

    The paper concerns the numerical solution of one-dimensional (1D) and two-dimensional (2D) advection-diffusion equations. For the numerical solution of the 1D advection-diffusion equation a method, originally proposed for solution of the 1D pure advection equation, has been developed. A modified equation analysis carried out for the proposed method allowed increasing of the resulting solution accuracy and consequently, to reduce the numerical dissipation and dispersion. This is achieved by proper choice of the involved weighting parameter being a function of the Courant number and the diffusive number. The method is adaptive because for uniform grid point and for uniform flow velocity the weighting parameter takes constant value whereas, for non-uniform grid and for varying flow velocity its value varies in the region of solution. For solution of the 2D transport equation the dimensional decomposition in the form of Strang splitting technique is used. Consequently, this equation is reduced to a series of the 1D equations with regard to x and y directions which next are solved using afore mentioned method. The results of computational experiments compared with the exact solutions confirmed that the proposed approaches ensure high solution accuracy of the transport equations.

  • Additive Effect of Bromides and Chlorides on the Performance of Perovskite Solar Cells Fabricated via Sequential Deposition
    • Jędrzej Szmytkowski
    • Damian Głowienka
    • Manon Verger
    • Harrie Gorter
    • Ilker Dogan
    • Wiljan Verhees
    • Mehrdad Najafi
    • Sjoerd Veenstra
    • Yulia Galagan
    2021 Pełny tekst JOURNAL OF POWER SOURCES

    A two-step sequential deposition method has been applied to prepare the solar cells with two types of perovskites Cs0.15FA0.85Pb(I0.95Cl0.05)3 and Cs0.15FA0.85Pb(I0.95Br0.05)3. In order to obtain the perovskite layers, the different sources of bromine and chlorine atoms were used for synthesis. The performance and time stability of chloride-based photocells are worse in comparison to the bromide-based devices. It can be explained by the effect of an accumulation of Cl atoms at the interfaces between the chloride-based perovskites and the layer of PCBM. Such a process causes an increasing of interface recombination. Also, the bulk density of states and, consequently, the bulk recombination of charge carriers seem to be higher for the perovskite layers obtained with chlorine atoms. The two-step technique applied to create the bromide perovskites less influences the photocells performance as in the case of one-step deposition. We can explain this observation by an existence of nucleation sites in the inorganic layer which improve the growth of a perovskite material.

  • Adsorption onto zeolites: molecular perspective
    • Azam Salmankhani
    • Farzad Seidi
    • Amin Hamed Mashhadzadeh
    • Payam Zarrintaj
    • Sajjad Habibzadeh
    • Ahmad Mohaddespour
    • Navid Rabiee
    • Eder C. Lima
    • Mohammadreza Shokouhimehr
    • Rajender S. Varma
    • Mohammad Saeb
    2021 CHEMICAL PAPERS

    2D minerals are among key elements of advanced systems, but the need for understanding their interactions/reactions with materials and systems in which they are involved necessitates tracking their molecular and atomic monitoring. Zeolitic structures are microporous materials formed in the nature through volcanic activities or synthesis. Because of their outstanding physicochemical properties like cation exchange capacity and excellent adsorption properties, zeolites have found application in diverse chemical processes, e.g., gas adsorption, water purification, and wastewater treatment. Prediction of zeolite performance for a targeted application saves time and expense as such projection could lead to the synthesis of optimum zeolite with adjusted properties. This review paper aims at encapsulating the latest findings on the use of 2D zeolite adsorbents studying three eminent molecular simulation techniques, namely molecular dynamics simulation, density functional theory, and Monte Carlo. Zeolites with precision structures and cost-efficiency for adsorption together with their adsorption capacity were correspondingly discussed in this review. Information gleaned from published reports on simulating zeolites’ adsorption properties could bridge with a brief comparison between the techniques mentioned to pave the way for scientists and industries to find the ideal method to predict zeolites performance and select the appropriate zeolite structure for the on-demand application.

  • Advanced sensitivity analysis of the impact of the temporal distribution and intensity of rainfall on hydrograph parameters in urban catchments
    • Francesco Fatone
    • Bartosz Szeląg
    • Adam Kiczko
    • Dariusz Majerek
    • Monika Majewska
    • Jakub Drewnowski
    • Grzegorz Łagód
    2021 Pełny tekst HYDROLOGY AND EARTH SYSTEM SCIENCES

    Knowledge of the variability of the hydrograph of outflow from urban catchments is highly important for measurements and evaluation of the operation of sewer networks. Currently, hydrodynamic models are most frequently used for hydrograph modeling. Since a large number of their parameters have to be identified, there may be problems at the calibration stage. Hence, sensitivity analysis is used to limit the number of parameters. However, the current sensitivity analytical methods ignore the effect of the temporal distribution and intensity of precipitation in a rainfall event on the catchment outflow hydrograph. This article presents a methodology of constructing a simulator of catchment outflow hydrograph parameters (volume and maximum flow). For this purpose, uncertainty analytical results obtained with the use of the GLUE (generalized likelihood uncertainty estimation) method were used. A novel analysis of the sensitivity of the hydrodynamic catchment models was also developed, which can be used in the analysis of the operation of stormwater networks and underground infrastructure facilities. Using the logistic regression method, an innovative sensitivity coefficient was proposed to study the impact of the variability of the parameters of the hydrodynamic model depending on the distribution of rainfall, the origin of rainfall (on the Chomicz scale), and the uncertainty of the estimated simulator coefficients on the parameters of the outflow hydrograph. The developed model enables the analysis of the impact of the identified SWMM (Storm Water Management Model) parameters on the runoff hydrograph, taking into account local rainfall conditions, which have not been analyzed thus far. Compared with the currently developed methods, the analyses included the impact of the uncertainty of the identified coefficients in the logistic regression model on the results of the sensitivity coefficient calculation. This aspect has not been taken into account in the sensitivity analytical methods thus far, although this approach evaluates the reliability of the simulation results. The results indicated a considerable influence of rainfall distribution and intensity on the sensitivity factors. The greater the intensity and rainfall were, the lower the impact of the identified hydrodynamic model parameters on the hydrograph parameters.

  • Advanced Ship Control Methods
    • Roman Śmierzchalski
    • Agnieszka Witkowska
    2021

    The chapter presents two main streams of research in vessel control at sea: dynamic positioning (DP) of the vessel and decision support in case of collision at sea. The control structure and basic requirements for the DP system are defined. Selected issues of automatic control of a dynamically positioned vessel are discussed. A review of advanced methods of controlling a DP ship is carried out, taking into account the tasks of particular subsystems. In the scope of decision support, the issue of collision avoidance at sea is discussed. This problem is defined as a dynamic multi-criteria optimization task which consists in looking for effective solutions that meet specific criteria within a set of acceptable solutions. To solve this problem, the evolutionary method of path planning is used.

  • Advanced super-hydrophobic polymer-based porous absorbents for the treatment of oil-polluted water
    • Lech Rowiński
    2021 CHEMOSPHERE

    The threat of environmental pollution caused by spilled oil is rapidly increasing along with the expansion of oil exploration, the development of maritime activities and industrial growth. Oil spill incidents usually affect seriously the ecosystem and human life. Therefore, the treatment and recovery of the oil spill have been considered as an ultra-important issue to protect the environment and to minimize its negative impacts on socio-economic activities. Among methods of oil spill recovery, porous materials have emerged as potential absorbents possessing the capacity of absorbing spilled oil at a fast rate, high adsorption capacity, good selectivity, and high reusability. In this review paper, two types of polymer-based porous absorbents modified surface and structure were introduced for the treatment strategy of the oil-polluted water. In addition, the absorption mechanism and factors affecting the adsorption capacity for oils and organic solvents were thoroughly analyzed. More importantly, characteristics of polymer-based porous materials were discussed in detail based on microstructure analysis, absorption efficiency, and reusability. In general, this paper has provided an overview and a comprehensive assessment of the use of advanced polymer-based porous materials for the treatment of oil-polluted water, although the impacts of environmental factors such as wind, wave, and temperature should be further investigated in the future.

  • ADVANCES IN MATERIALS SCIENCE EDITORIAL ON THE JOURNAL'S 20th ANNIVERSARY
    • Jerzy Łabanowski
    • Dariusz Fydrych
    2021 Pełny tekst Advances in Materials Science

    Editorial on the occasion of the 20th anniversary of Advances in Materials Science journal.

  • Aiming at methods’ wider adoption: Applicability determinants and metrics
    • Rafał Leszczyna
    2021 Pełny tekst Computer Science Review

    Numerous computer science methods and techniques have been proposed by the scientific community. However, depending on the domain, only their minor fraction has met wider adoption. This paper brings attention to the concept of applicability - the notion that is well acknowledged in the scientific field but have not been analysed with respect to determinants, metrics and systematisation. The primary objective of the study was to identify applicability determinants and metrics and consolidate them into a taxonomy, based on a systematic process. To achieve the objective, a methodological literature review supported with operationalisation activities were applied. As a result, more than thirty descriptors of applicability were introduced in the proposed applicability taxonomy, and a similar number of metrics has been elicited. Based on them, a questionnaire for evaluation of the method's applicability was created and applied to the evaluation of a currently developed cybersecurity risk assessment method that aims at broader market uptake. The analysis provided indications on its further developments, but also findings of a more universal character.

  • Aktualne trendy i rekomendacje w zakresie usuwania mikrozanieczyszczeń należących do farmaceutyków i pestycydów ze ścieków komunalnych
    • Przemysław Kowal
    • Dominika Grubba
    • Jacek Mąkinia
    2021 Forum Eksploatatora

    Mikrozanieczyszczenia, przede wszystkim pestycydy oraz farmaceutyki, zyskują coraz większe zainteresowanie zarówno ze strony środowiska naukowego, administracji publicznej, jak również międzynarodowych organizacji rządowych i pozarządowych. W ostatnich latach jest obserwowany stały wzrost stężeń mikrozanieczyszczeń zarówno w glebie, jak i środowisku wodnym. Szczególne zagrożenie płynące ze strony pestycydów i farmaceutyków wynika z powszechności ich stosowania.

  • Aktualne wymagania w zakresie ochrony przeciwporażeniowej w instalacjach niskiego napięcia
    • Stanisław Czapp
    2021

    W referacie zaprezentowano główne zasady związane z projektowaniem ochrony przeciwporażeniowej w instalacjach niskiego napięcia oraz sprawdzaniem jej stanu. Przedstawiono również podstawy ochrony przeciwporażeniowej w instalacjach ładowania pojazdów elektrycznych oraz w instalacjach niskiego napięcia zlokalizowanych w strefie oddziaływania kolejowej sieci trakcyjnej.

  • Algorithmic Human Resources Management - Perspectives and Challenges
    • Łukasz Sienkiewicz
    2021 Pełny tekst Annales Universitatis Mariae Curie-Skłodowska, Sectio H Oeconomia

    Theoretical background: Technology – most notably processes of digitalisation, the use of artificial intelligence, machine learning, big data and prevalence of remote work due to pandemic – changes the way organizations manage human resources. One of the increasing trends is the use of so-called “algorithmic management”. It is notably different than previous e-HRM or HRIS (human resources information systems) applications, as it automates HR-related duties. Algorithms, being autonomous computational formulae, are considered objective and mathematically correct decision-making mechanisms. Limiting human involvement and oversight of the labour process might lead to serious ethical and managerial challenges. Many areas – previously being sole responsibility of managers (including HR managers), like employment relations, hiring, performance management, remuneration – are increasingly affected, or even taken over, by algorithmic management. Purpose of the article: The purpose of this article is to review the development, perspectives and challenges (including possible biases and ethical considerations) of algorithmic human resources management. This novel approach is fuelled by the speeding processes of digitalisation, the use of artificial intelligence, big data and increased analytical capabilities and applications used by contemporary companies. Algorithms are formulas that autonomously make decisions based on statistical models or decision rules without human intervention. Therefore, the use of algorithmic HRM automates decision-making processes and duties of human resources managers, thereby limiting human involvement and oversight, which can have negative consequences for the organization. Research methods: The article provides a critical literature review of theoretical sources and empirical evidence on the application of algorithmic human resources management practices. Scientific journals in the field of human resources management and technology applications have been reviewed, as well as research reports from academic institutions and renowned international organizations.

  • All-gather Algorithms Resilient to Imbalanced Process Arrival Patterns
    • Jerzy Proficz
    2021 Pełny tekst ACM Transactions on Architecture and Code Optimization

    Two novel algorithms for the all-gather operation resilient to imbalanced process arrival patterns (PATs) are presented. The first one, Background Disseminated Ring (BDR), is based on the regular parallel ring algorithm often supplied in MPI implementations and exploits an auxiliary background thread for early data exchange from faster processes to accelerate the performed all-gather operation. The other algorithm, Background Sorted Linear synchronized tree with Broadcast (BSLB), is built upon the already existing PAP-aware gather algorithm, that is, Background Sorted Linear Synchronized tree (BSLS), followed by a regular broadcast distributing gathered data to all participating processes. The background of the imbalanced PAP subject is described, along with the PAP monitoring and evaluation topics. An experimental evaluation of the algorithms based on a proposed mini-benchmark is presented. The mini-benchmark was performed over 2,000 times in a typical HPC cluster architecture with homogeneous compute nodes. The obtained results are analyzed according to different PATs, data sizes, and process numbers, showing that the proposed optimization works well for various configurations, is scalable, and can significantly reduce the all-gather elapsed times, in our case, up to factor 1.9 or 47% in comparison with the best state-of-the-art solution.

  • Amberlyst-15 catalysed synthesis of novel indole derivatives under ultrasound irradiation: Their evaluation as serotonin 5‑HT2C receptor agonists
    • Kazi Hossain
    • Manojit Pal
    2021 Pełny tekst BIOORGANIC CHEMISTRY

    A series of indole based novel Schiff bases was designed as potential agonists of 5‑HT2C receptor that was supported by docking studies in silico. These compounds were synthesized via Amberlyst-15 catalysed condensation of an appropriate pyrazole based primary amine with the corresponding indole-3-aldehyde under ultrasound irradiation at ambient temperature. A number of target Schiff bases were obtained in good yields (77-87%) under mild conditions within 1 h. Notably, the methodology afforded the corresponding pyrazolo[4,3-d]pyrimidin-7(4H)-one derivatives when the primary amine was replaced by a secondary amine. Several Schiff bases showed agonist activity when tested against human 5-HT2C using luciferase assay in HEK293T cells in vitro. The SAR (Structure-Activity-Relationship) studies suggested that the imine moiety was more favorable over its cyclic form i.e. the corresponding pyrazolopyrimidinone ring. The Schiff bases 3b (EC50 1.8 nM) and 3i (EC50 5.7 nM) were identified as the most active compounds and were comparable with Lorcaserin (EC50 8.5 nM). Also like Lorcaserin, none of these compounds were found to be PAM of 5-HT2C. With ~24 and ~150 fold selectivity towards 5-HT2C over 5-HT2A and 5-HT2B respectively the compound 3i that reduced locomotor activity in zebrafish (Danio rerio) larvae model emerged as a promising hit molecule for further study.

  • Ambisoniczna mapa wybranych miejsc w Trójmieście z obrazem 360°
    • Cezary Pietrzak
    • Piotr Odya
    2021

    W projekcie, który zostanie opisany w niniejszym rozdziale, założonym celem było stworzenie ambisonicznej mapy Trójmiasta w formie aplikacji internetowej. Materiały wideo w technologii 360° z dźwiękiem w postaci sygnału ambisonicznego zostały zarejestrowane w wybranych lokalizacjach uznanych za charakterystyczne dla tej aglomeracji. Celem badawczym projektu było porównanie dostępnych algorytmów miksowania sygnałów ambisonicznych przez przeprowadzenie testów odsłuchowych. Wykonano test porównań parami, aby uzyskać informacje o preferencjach odnośnie do występowania w nagraniach ambisonicznych dodatkowego podkładu stereo oraz jego poziomu głośności. W drugim z testów zbadano, jaki wpływ na odbiór nagrania ambisonicznego ma sposób oraz stopień jego przetwarzania. Wnioski z analizy wyników obu testów posłużyły jako wskazówki przy postprodukcji nagrań. Otrzymane materiały zostały zamieszczone na interaktywnej mapie w aplikacji internetowej.

  • Amino Acid and Peptide‐Based Antiviral Agents
    • Andrzej Skwarecki
    • Michał Nowak
    • Maria Milewska
    2021 CHEMMEDCHEM

    A significant number of antiviral agents used in clinical practice are amino acids, short peptides, or peptidomimetics. Among them, several HIV protease inhibitors (e. g. lopinavir, atazanavir), HCV protease inhibitors (e. g. grazoprevir, glecaprevir), and HCV NS5A protein inhibitors have contributed to a significant decrease in mortality from AIDS and hepatitis. However, there is an ongoing need for the discovery of new antiviral agents and the development of existing drugs; amino acids, both proteinogenic and non-proteinogenic in nature, serve as convenient building blocks for this purpose. The synthesis of nonproteinogenic amino acid components of antiviral agents could be challenging due to the need for enantiomerically or diastereomerically pure products. Herein, we present a concise review of antiviral agents whose structures are based on amino acids of both natural and unnatural origin. Special attention is paid to the synthetic aspects of non-proteinogenic amino acid components of those agents.

  • Amino Acid Based Antimicrobial Agents – Synthesis and Properties
    • Michał Nowak
    • Andrzej Skwarecki
    • Maria Milewska
    2021 Pełny tekst CHEMMEDCHEM

    Structures of several dozen of known antibacterial, antifungal or antiprotozoal agents are based on the amino acid scaffold. In most of them, the amino acid skeleton is of a crucial importance for their antimicrobial activity, since very often they are structural analogs of amino acid intermediates of different microbial biosynthetic pathways. Particularly, some aminophosphonate or aminoboronate analogs of protein amino acids are effective enzyme inhibitors, as structural mimics of tetrahedral transition state intermediates. Synthesis of amino acid antimicrobials is a particular challenge, especially in terms of the need for enantioselective methods, including the asymmetric synthesis. All these issues are addressed in this review, summing up the current state-of-the-art and presenting perspectives fur further progress.

  • AMO perspectives on the well-being of neurodivergent human capital
    • Joanna Maria Szulc
    • Julie Davies
    • Michał Tomasz Tomczak
    • Frances Mcgregor
    2021 Pełny tekst Employee Relations

    Existing management research and management practices frequently overlook the relationship between the above-average human capital of highly functioning neurodivergent employees, their subjective well-being in the workplace and performance outcomes. This paper calls for greater attention to the hidden human capital associated with neurodiversity by mainstreaming implementation of neurodiversity-friendly policies and practices. Drawing on the ability, motivation and opportunity (AMO) framework, this conceptual paper integrates research on employee neurodiversity and well-being to provide a model of HR-systems level and human capital development policies, systems and practices for neurodivergent minorities in the workplace. This paper illustrates that workplace neurodiversity, like biodiversity, is a natural phenomenon. For subjective individual psychological and organisational well-being, neurodivergent employees require an empathetic culture and innovative talent management approaches that respect cognitive differences. The case is made for neurodivergent human capital development and policy-makers to promote inclusive employment and decent work in a context of relatively high unemployment for neurodivergent individuals. This paper extends current debates on organisational equality, diversity and inclusion to a consideration of workplace well-being for highly functioning neurodivergent workers. It calls for more equitable and empathetic approaches to investing in employees with neurodevelopmental and cognitive disabilities.

  • Among Friends: The Role of Friendship in Alternative Organizations
    • Monika Kostera
    • Marta Szeluga-Romańska
    2021 Pełny tekst Zarządzanie Mediami

    Friendship, a mutual and profound relationship, permeates history of human culture and occurs in all social situations, including professional and informal human activities. In organizations, it devel­ops through processes of communication and generates a communication culture of kindness and support. Organizational friendship enhances work engagement and satisfaction, as well as helps to promote individual ends. This article investigates the more vital significance of friendship in alter­native organizations. Such organizations, operating at the margins of the currently dominant profit-oriented business model, offer a plethora of insights of possible structures and practices. Our ethno­graphic qualitative research shows the implications of workplace friendship as organizing principle. It helps to make organizations more humane, and redressed the moral imbalance, so prevalent in contemporary organizing and management. This has important implications for any kind of com­munication, creating social awareness around important themes related to management and organ­izations. Patterns of friendship are meaningful for organizing and organizations and their most vi­tal significance concerns the area of social communication.

  • Amygdalin: Toxicity, Anticancer Activity and Analytical Procedures for Its Determination in Plant Seeds
    • Ewa Jaszczak-Wilke
    • Żaneta Polkowska
    • Marek Koprowski
    • Krzysztof Owsianik
    • Alyson E. Mitchell
    • Piotr Bałczewski
    2021 Pełny tekst MOLECULES

    Amygdalin (D-Mandelonitrile 6-O--D-glucosido--D-glucoside) is a natural cyanogenic glycoside occurring in the seeds of some edible plants, such as bitter almonds and peaches. It is a medically interesting but controversial compound as it has anticancer activity on one hand and can be toxic via enzymatic degradation and production of hydrogen cyanide on the other hand. Despite numerous contributions on cancer cell lines, the clinical evidence for the anticancer activity of amygdalin is not fully confirmed. Moreover, high dose exposures to amygdalin can produce cyanide toxicity. The aim of this review is to present the current state of knowledge on the sources, toxicity and anticancer properties of amygdalin, and analytical methods for its determination in plant seeds.

  • An analysis of wind conditions at pedestrian level in the selected types of multi-family housing developments
    • Marta Poćwierz
    • Katarzyna Zielonko-Jung
    2021 Pełny tekst ENVIRONMENTAL FLUID MECHANICS

    The following article addresses the issue of wind conditions around urban building development at pedestrian level. Factors that depend on those issues include wind comfort and air quality within urbanized spaces. The conditions specific of cities located in a temperate climate zone have been taken into account. The article is intended to identify aerodynamic phenomena characteristic of the three basic types of multi-family building development (section, linear, quarter). For each type of buildings, three different variants were considered on the basis of land use efficiency (low, medium, high) each type of buildings is characterised with. The models illustrate the patterns observed within European urban planning thought and have been developed in accordance with contemporary architectural and urban conditions, as well as with legal requirements and good practices in force in Poland. Experimental research in the wind tunnel has been conducted by means of two complementary field methods (visualization and erosion). The application of these two methods made it possible to obtain data on airflow direction layouts and on changes in airflow velocity. Subsequently, the results obtained in the study have been compared. Thus, more and less favourable geometrical layouts in respect to aerodynamic phenomena have been indicated.

  • An Automated Method for Biometric Handwritten Signature Authentication Employing Neural Networks
    • Mariusz Kurowski
    • Andrzej Sroczyński
    • Georgis Bogdanis
    • Andrzej Czyżewski
    2021 Pełny tekst Electronics

    Handwriting biometrics applications in e-Security and e-Health are addressed in the course of the conducted research. An automated graphomotor analysis method for the dynamic electronic representation of the handwritten signature authentication was researched. The developed algorithms are based on dynamic analysis of electronically handwritten signatures employing neural networks. The signatures were acquired with the use of the developed electronic pen described in the paper. The triplet loss method was used to train a neural network suitable for writer-invariant signature verification. The signatures represented by anchor and positive are master signatures from the same class, representing a single person, that should be close to each other in multidimensional output space. For each signature of the three, the same neural network calculates a fixed-length latent space representation. The hand-corrected dataset containing 10,622 was used in order to train and evaluate proposed network. After learning, the network was tested and achieved mean 5.77% EER. The use of the triplet loss algorithm to teach neural network generation of embeddings has proven to give good results in terms of grouping of similar signatures and separating them from signatures representing different people.

  • An Efficient Noisy Binary Search in Graphs via Median Approximation
    • Dariusz Dereniowski
    • Aleksander Łukasiewicz
    • Przemysław Uznański
    2021 LECTURE NOTES IN COMPUTER SCIENCE

    Consider a generalization of the classical binary search problem in linearly sorted data to the graph-theoretic setting. The goal is to design an adaptive query algorithm, called a strategy, that identifies an initially unknown target vertex in a graph by asking queries. Each query is conducted as follows: the strategy selects a vertex q and receives a reply v: if q is the target, then =, and if q is not the target, then v is a neighbor of q that lies on a shortest path to the target. Furthermore, there is a noise parameter 0≤<12 which means that each reply can be incorrect with probability p. The optimization criterion to be minimized is the overall number of queries asked by the strategy, called the query complexity. The query complexity is well understood to be O(ε−2log) for general graphs, where n is the order of the graph and ε=1/2−. However, implementing such a strategy is computationally expensive, with each query requiring possibly O(^2) operations. In this work we propose two efficient strategies that keep the optimal query complexity. The first strategy achieves the overall complexity of O(ε−1log) per a single query. The second strategy is dedicated to graphs of small diameter D and maximum degree Δ and has the average complexity of O(+ε−2Δlog) per query. We point out that we develop an algorithmic tool of graph median approximation that is of independent interest: the median can be efficiently approximated by finding a vertex minimizing the sum of distances to a randomly sampled vertex subset of size O(ε−2log).