2020 - Repozytorium publikacji - Politechnika Gdańska

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LONG-TERM RISK CLASS MIGRATIONS OF NON-BANKRUPT AND BANKRUPT ENTERPRISES
- Tomasz Korol
2020 Pełny tekst Journal of Business Economics and Management
This paper investigates how the process of going bankrupt can be recognized much earlier by enterprises than by traditional forecasting models. The presented studies focus on the assessment of credit risk classes and on determination of the differences in risk class migrations between non-bankrupt enterprises and future insolvent firms. For this purpose, the author has developed a model of a Kohonen artificial neural network to determine six different classes of risk. Long-term analysis horizon of 15 years before the enterprises went bankrupt was conducted. This long forecasting horizon allows one to identify, visualize and compare the intensity and pattern of changes in risk classes during the 15-year trajectory of development between two separate groups of companies (150 bankrupt and 150 non-bankrupt firms). The effectiveness of the forecast of the developed model was compared to three popular statistical models that predict the financial failure of companies. These studies represent one of the first attempts in the literature to identify the long-term behavioral pattern differences between future “good” and “bad” enterprises from the perspective of risk class migrations.
Looking for the Optimal Location of an Eco-District within a Metropolitan Area: The Case of Tricity Metropolitan Area
- Julia Kurek
- Justyna Martyniuk-Pęczek
2020 Pełny tekst Sustainability
Compact housing structures located in city centers are considered to be the most energy and environmentally eective, mainly due to the access to services, transport networks and municipal infrastructures. There is the question of why so many of the acknowledged ecological housing complexes are located on the outskirts of cities or suburbs. Numerous cities decide to introduce strategies either to densify city centers, hoping to improve energy eciency. The Tricity metropolitan area is a special case undergoing dynamic transformation, and its development overlaps with the processes of both planned densification of the center as well as uncontrolled suburbanization. The goal of this study was to find the correlation between optimal location of an eco-district from the functional center of the Tricity metropolitan area, allowing for the most favorable energy and environmental parameters related both to the architectural and urban scale. The research was conducted in four dierent scenarios, concerning present and future development. In these scenarios, specific locations were examined, and the following were compared: total energy consumption, ecological footprint and CO2 lifecycle emissions. This study shows the possibility for suburban housing complexes with appropriate parameters in an edge city model to have the same or better results than complexes situated closer to the functional center of the city. This is mainly due to the building’s energy eciency, sustainable mobility, municipal infrastructure and relevant service access. The research proves the importance of implementing sustainable energy-saving and environmentally oriented activities at both an architectural and urban scale planning process.
Love your mistakes!—they help you adapt to change. How do knowledge, collaboration and learning cultures foster organizational intelligence?
- Wioleta Kucharska
- Denise A. D. Bedford
2020 Pełny tekst JOURNAL OF ORGANIZATIONAL CHANGE MANAGEMENT
Purpose: The study aims to determine how the acceptance of mistakes is related to adaptability to change in a broad organizational context. Therefore it explores how knowledge, collaboration, and learning culture (including “acceptance of mistakes”) might help organizations overcome their resistance to change. Methodology: The study uses two sample groups: students aged 18–24 (330 cases) and employees aged >24 (326 cases) who work in knowledge-driven organizations. Structural equation models were developed, assessed, and compared. Findings: The effect of the “learning climate” on “adaptability to change” mediated by “acceptance of mistakes” has been detected for young students aged 18-24; however this relationship is not significant for business employees aged >24. This result suggests that organizations, unlike universities, do not use mistakes as a tool to support learning that is to lead to change. Limitations: Both samples used in the study come from Poland. The business sample is in the majority represented by small and medium-sized enterprises. Therefore the presented findings may only apply to Poland. Practical implications: Acceptance of mistakes is vital for developing a learning culture. Mistakes help employees adapt to change. Hence, a learning culture that excludes the acceptance of mistakes is somehow artificial and may be unproductive. Paradoxically, the findings reveal that the fact that employee intelligence (adaptability to change) improves via mistakes does not mean that organizational intelligence will also increase. Thus, organizations that do not develop mechanisms of learning from mistakes lose the learning potential of their employees. Scientific implications: The study presents mistakes as a valuable resource that enables the adaptation and development of intelligence. Hence, this study brings to attention a promising research area of “learning from organizational mistakes” in the context of adaptability to change. The study should be replicated for large Polish companies, international companies, and other countries to get a total picture of this phenomenon. Moreover, the acceptance of mistakes would be a significant step to advance learning technologies. Novelty: This study proposes a constant learning culture scale that includes the “acceptance of mistakes” and “learning climate” dimensions. Further, it empirically proves the value of mistakes for adaptability to change.
Low energy differential elastic electron scattering from trichloromethane
- B Diaz
- G Tatreau
- Borna Hlousek
- Mateusz Zawadzki
- Murtadha Khakoo
2020 Pełny tekst Journal of Physics : Conference Series
Experimental differential cross sections for low energy electron scattering from trichloromethane is measured utilizing a crossed electron-molecular beam experiment via the relative flow method, for the incident electron energies in the range of E = 0.5 eV-30 eV and the scattering angles in the range of θ = 10◦ − 130◦ .
Low energy elastic electron scattering from benzonitrile (C6H5CN)
- G Tatreau
- B Diaz
- F Alharthi
- Mateusz Zawadzki
- Murtadha Khakoo
2020 Pełny tekst Journal of Physics : Conference Series
We present experimental differential elastic scattering cross sections (DCSs) for low energy electron scattering from benzonitrile along with integral and momentum-transfer cross sections that are determined from these DCSs. The measurements of DCSs are obtained using the relative flow method with helium as the standard gas, in a crossed electron-molecular gas beam arrangement. Our measurements are made at incident electron energies in the range of 1 − 30 eV and scattering angles in the range of (10◦ -130◦ ).
Low energy electron mass stopping power in H2
- Mateusz Zawadzki
- Murtadha Khakoo
2020 Pełny tekst Journal of Physics : Conference Series
We present experimental mass stopping powers of electrons in gaseous H2 obtained with a newly developed electron time-of-flight spectrometer, for the incident electron energy range of 10eV to 25eV. In our procedure the average energy loss is derived from our conversion of measured electron time-of-flight spectra into equivalent electron energy loss spectra so as to obtain the values of mass stopping power for electron scattering from H2.
Low energy inelastic electron scattering from carbon monoxide: I. excitation of the a3Π, a’3Σ+ and AΠ1 electronic states.
- Mateusz Zawadzki
- Morty Khakoo
- Logan Voorneman
- Luka Ratkovic
- Zdenek Masin
- Karel Houfek
- Amar Dora
- Russ Laher
- Jonathan Tennyson
2020 JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS
Differential scattering cross sections for electron excitation of the three lowest excited electron states of carbon monoxide are obtained experimentally using low-energy electron energy-loss spectroscopy and theoretically using the R-matrix method. The incident electron energies range from near-threshold of 6.3 eV to 20 eV. Experimental scattering angles range from 20◦ to 120◦. The normalization of the experimental cross sections is made to available experimental elastic scattering data (Gibson et al 1996 J. Phys. B: At. Mol. Opt. Phys. 29 3197). The R-matrix calculations use three distinct close-coupling models and their results are compared to available experimental and theoretical cross sections. The overall comparison leads to significantly improved description of the excitation cross sections for this target.
Low noise poroelastic road pavements based on modified asphalt binder
- Jerzy Ejsmont
- Beata Świeczko-Żurek
- Władysław Gardziejczyk
2020
Tire/road noise is one of the most important environmental problems related to road traffic. As the most effective way to fight noise is reduction of sound emission from the source, a lot of work is being done to improve tire and road surfaces construction. This paper describes the first “road” results obtained within the SEPOR project, which is focused on developing a low noise poroelastic road surface based on bituminous binder. It is also a continuation of the paper presented during NOISE-CON 2019 conference that described the preliminary results of laboratory tests and small scale experiments. The paper presents results of measurements performed on two road sections paved with poroelastic material in 2019. The technologies used on these test sections were aimed at eliminating the problems that occurred with poroelastic surfaces using polyurethane binder and in particular increasing the durability of the surface (especially in terms of adhesion to the base layer) as well as reducing rolling resistance. The paper describes the results of tire noise, sound absorption, drainage properties and rolling resistance tests. Experience to date indicates that bituminous binder has eliminated the most troublesome problems of poroelastic road surfaces, but at this stage of development the achieved noise reduction is not as high as expected so more trials will be performed in 2020.
Low-Cost Automated Design of Compact Branch-Line Couplers
- Adrian Bekasiewicz
2020 Pełny tekst SENSORS
Branch-line couplers (BLCs) are important components of wireless communication systems. Conventional BLCs are often characterized by large footprints which make miniaturization an important prerequisite for their application in modern devices. State-of-the-art approaches to design of compact BLCs are largely based on the use of high-permittivity substrates and multi-layer topologies. Alternative methods involve replacement of transmission-line sections of the circuit with their composite counterparts referred to as compact cells (CCs). Owing to efficient use of available space, CC-based couplers are often characterized by small footprints. Design of compact BLCs is normally conducted based on engineering experience. The process is laborious and requires many adjustments of topology followed by manual or, semi-automatic tuning of design parameters. In this work, a framework for low-cost automated design of compact BLCs using pre-defined CCs is proposed. Low cost of the presented design technique is ensured using equivalent-circuit models, space mapping correction methods, and trust-region-based local optimization algorithms. Performance of the framework is demonstrated using three examples concerning design of unequal-power split coupler, comparison of automatically generated compact BLCs, as well as rapid re-design of the coupler for different substrates. Furthermore, the approach has been benchmarked against the state-of-the-art methods for low-cost design of circuits.
Low-cost data-driven modelling of microwave components using domain confinement and PCA-based dimensionality reduction
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
2020 IET Microwaves Antennas & Propagation
Fast data-driven surrogate models can be employed as replacements of computationally demanding full-wave electromagnetic simulations to facilitate the microwave design procedures. Unfortunately, practical application of surrogate modelling is often hindered by the curse of dimensionality and/or considerable nonlinearity of the component characteristics. This paper proposes a simple yet reliable approach to cost-efficient modelling of miniaturized microwave components which adopts two fundamental mechanisms to improve the computational efficiency of setting up the surrogate. Firstly, the model domain is confined-using a set of pre-optimized reference designs-to the region of the parameter space containing high-quality designs with respect to the relevant performance figures. Secondly, the domain is spanned by the selected principal components of the reference set for dimensionality reduction. Consequently, the surrogate model, covering wide ranges of the device parameters and operating conditions, can be established using a fraction of training data samples required by conventional approaches, without compromising its predictive power. The proposed technique is illustrated using two miniaturized microstrip components: a rat-race coupler (RRC) and an impedance matching transformer. The following accuracies of the PCA-based surrogates have been obtained: 0.9% for RRC and 2.1% for the transformer (for 800 training data samples).
Low-cost performance-driven modelling of compact microwave components with two-layer surrogates and gradient kriging
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
2020 Pełny tekst AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
Utilization of electromagnetic (EM) simulation tools has become indispensable for reliable evaluation of microwave components. As the cost of an individual analysis may already be considerable, the computational overhead associated with EM-driven tasks that require massive simulations (e.g., optimization) may turn prohibitive. One of mitigation methods is the employment of equivalent network models. Yet, they are incapable of accounting for cross-coupling effects that occur in devices of complex geometries. Another option are fast replacement models (surrogates), especially the data-driven ones: readily available, generic and problem independent. Unfortunately, due to the curse of dimensionality, their applicability is limited to low-dimensional parameter spaces and narrow parameter ranges. From the utility perspective, however, the surrogate has to be valid over broad ranges of parameters and operating conditions. The recently reported performance-modeling techniques (especially nested-kriging) allow for rendering such surrogates even for complex devices. Key concept is to carry out the modeling process within a confined domain, being a subset of the parameter space that encompasses the designs of high-quality regarding the performance figures of choice. The goal of this work is to reduce the cost of reference design acquisition, which adds up to the total cost of constructing the surrogate. Toward this end, gradient-enhanced kriging is incorporated into the performance-driven modeling framework. The predictive power of the surrogates rendered using our approach by far exceeds that of the conventional methods and is comparable to the original nested kriging technique while requiring a significantly smaller number of reference designs (thus, the CPU cost). These features are demonstrated using a three-section transformer and a rat-race coupler.
Low-Cost Surrogate Modeling of Miniaturized Microwave Components Using Nested Kriging
- Anna Pietrenko-Dąbrowska
- Sławomir Kozieł
2020 APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY JOURNAL
In the paper, a recently reported nested kriging methodology is employed for modeling of miniaturized microwave components. The approach is based on identifying the parameter space region that contains high-quality designs, and, subsequently, rendering the surrogate in this subset. The results obtained for a miniaturized unequal-power-split rat-race coupler and a compact three-section impedance transformer demonstrate reliability of the method even for highly-dimensional parameter spaces, as well as its superiority over conventional modeling methods.
Low-Power Receivers for Wireless Capacitive Coupling Transmission in 3-D-Integrated Massively Parallel CMOS Imager
- Grzegorz Blakiewicz
- Miron Kłosowski
- Waldemar Jendernalik
- Jacek Jakusz
- Stanisław Szczepański
2020 Pełny tekst IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
The paper presents pixel receivers for massively parallel transmission of video signal between capacitive coupled integrated circuits (ICs). The receivers meet the key requirements for massively parallel transmission, namely low-power consumption below a single μW, small area of less than 205 μm2, high sensitivity better than 160 mV, and good immunity to crosstalk. The receivers were implemented and measured in a 3-D IC (two face-to-face stacked chips fabricated in CMOS 180 nm process). The maximum throughput of 20 Mbps of single receiver has been achieved using a return-to-zero (RZ) code. The static and dynamic power consumption of the single receiver are below 0.2 μW and 0.3 μW/MHz, respectively. The design approach for cost-effective inter-chip massively parallel transmission of photosensor signals with pulse position modulation (PPM) has been also performed. With this approach and the developed receivers it is possible to transfer between chips 9-10 bit images at a speed of over 1k fps.
LSTM-based method for LOS/NLOS identification in an indoor environment
- Alicja Olejniczak
- Olga Błaszkiewicz
- Krzysztof Cwalina
- Piotr Rajchowski
- Jarosław Sadowski
2020
Due to the multipath propagation, harsh indoor environment significantly impacts transmitted signals which may adversely affect the quality of the radiocommunication services, with focus on the real-time ones. This negative effect may be significantly reduced (e.g. resources management and allocation) or compensated (e.g. correction of position estimation in radiolocalisation) by the LOS/NLOS identification algorithm. This paper investigates the idea of improving already existing method of LOS/NLOS classification, based on a deep feedforward neural network, by the LSTM-based model which allows extracting and analysing time-related dependencies occurring in a radio channel.
Machine Learning and Text Analysis in an Artificial Intelligent System for the Training of Air Traffic Controllers
- Tetiana Shmelova
- Yuliya Sikirda
- Nina Rizun
- Vitaliy Lazorenko
- Volodymyr Kharchenko
2020 Pełny tekst
This chapter presents the application of new information technology in education for the training of air traffic controllers (ATCs). Machine learning, multi-criteria decision analysis, and text analysis as the methods of artificial intelligence for ATCs training have been described. The authors have made an analysis of the International Civil Aviation Organization documents for modern principles of ATCs education. The prototype of the neural network for evaluating the timeliness and correctness of the decision making by ATCs has been developed. The new theoretical and practical tasks for simulation and pre-simulation training have been obtained using expert judgment method. The methodology for sentiment analyzing the airline customers' opinions has been proposed. In addition, the examples of artificial intelligence systems and expert systems by the authors, students and colleagues from National Aviation University, Ukraine and Gdansk University of Technology, Poland have been proposed.
Magnetic switching of Kerker scattering in spherical microresonators
- Grigorios P. Zouros
- Georgios D. Kolezas
- Evangelos Almpanis
- Konstantinos Baskourelos
- Tomasz Stefański
- Kosmas L. Tsakmakidis
2020 Pełny tekst Nanophotonics
Magneto-optical materials have become a key tool in functional nanophotonics, mainly due to their ability to offer active tuning between two different operational states in subwavelength structures. In the long-wavelength limit, such states may be considered as the directional forward- and back-scattering operations, due to the interplay between magnetic and electric dipolar modes, which act as equivalent Huygens sources. In this work, on the basis of full-wave electrodynamic calculations based on a rigorous volume integral equation (VIE) method, we demonstrate the feasibility of obtaining magnetically-tunable directionality inversion in spherical microresonators (THz antennas) coated by magneto-optical materials. In particular, our analysis reveals that when a high-index dielectric is coated with a magneto-optical material, we can switch the back-scattering of the whole particle to forward-scattering simply by turning off/on an external magnetic field bias. The validity of our calculations is confirmed by reproducing the above two-state operation, predicted by the VIE, with full-wave finite-element commercial software. Our results are of interest for the design of state-of-the-art active metasurfaces and metalenses, as well as for functional nanophotonic structures, and scattering and nanoantennas engineering.
Magnetoacoustic Heating of Plasma Caused by Periodic MagnetosoundPerturbations with Discontinuities in a Quasi-Isentropic Magnetic Gas
- Anna Perelomova
2020 Pełny tekst Archives of Acoustics
The magnetoacoustic heating of plasma by harmonic or periodic saw-tooth perturbations at a trans-ducer is theoretically studied. The planar fast and slow magnetosound waves are considered. The wavevector may form an arbitrary angleθwith the equilibrium straight magnetic field. In view of variableθand plasma-β, the description of magnetosound perturbations and appropriate magnetosound heatingis fairly difficult. The scenario of heating depends not only on plasma-βandθ, but also on a balancebetween nonlinear attenuation at the shock front and inflow of energy into a system. Under some condi-tions, the average over the magnetosound period force of heating may tend to a positive or negative limit,tend to zero, or may remain constant when the distance from a transducer tends to infinity. Dynamicsof temperature specifying heating differs in thermally stable and unstable cases and occurs unusually inthe isentropically unstable flows.
Making full and immediate Open Access a reality through the repository route – the role of open repositories in implementation of Plan S.
- Anna Wałek
2020 Pełny tekst Przegląd Biblioteczny
Thesis/Objective: In 2018, research funding institutions associated in cOAlitionS issued PlanS document which aims to accelerate the transition to full and immediate Open Access to publications from publicly funded research until January 2021. Among the recommendations, which mainly relate to publishing in the Open Access model and its financing, there are also guidelines on the implementation of Plan S assumptions through the so-called “green route”, or “repository route”. These requirements are particularly important for libraries whose role in creating tools and platforms for Open Science is crucial. One of the Coalition S member organisations is the National Science Centre (NSC), which in May 2020 introduced an Open Access policy, thus implementing the Plan S assumptions in Poland. The article presents the requirements of Plan S concerning open repositories. It defines their role in implementing the vision of openness on the example of the Bridge of Knowledge repository, created by the Gdańsk University of Technology. Research methods: The critical literature review was used to analyse the content of foreign and Polish LIS literature published in the years 2018-2020. Also, official documents issued by the European Commission were analysed, as well as websites devoted to Open Access and PlanS implementation. Results and conclusions: For research financed by cOAlition S covered by the requirements of Plan S, all peer-reviewed scientific articles must be published in locations that meet specific needs. If such an article is published at the subscription site and then immediately submitted to the Open Access repository, the requirements for repositories must also be met. Although the primary attention of the institutions implementing Plan S is focused on financing publications, especially under the so-called transformation agreements, the repository option should also be monitored and developed. It is associated with lower costs, and at the same time provides immediate open access, even to articles in subscription journals. By analysing the requirements and comparing them with the existing solutions, the repositories can be checked for compliance with Plan S. Not all criteria are, however, entirely clear to interpret and possible to implement.
Manufacturing of Lightweight Aggregates as an Auspicious Method of Sewage Sludge Utilization
- Jerzy Korol
- Marcin Głodniok
- Aleksander Hejna
- Tomasz Pawlik
- Błażej Chmielnicki
- Jan Bondaruk
2020 Pełny tekst Materials
: Sewage sludge is a high-volume and low-cost waste commonly generated worldwide, so its utilization is a vital issue. The application of this waste in the manufacturing of lightweight aggregates was investigated. The process was performed using intensive mixers with volumes of 5 and 30 L, as well as the industrial 500 L mixer. Then, granulates were sintered in a tube furnace. The influence of composition and mixer size on the particle size, microstructure, mechanical performance, and stability of lightweight aggregates in different environments was analyzed. The best results were obtained for a 500 L mixer, enhancing the industrial potential of the presented process. Increasing the share of sewage sludge in the composition of aggregates enhanced their porosity and reduced the specific weight, which caused a drop in compressive strength. Nevertheless, for all analyzed materials, the mechanical performance was superior compared to many commercial products. Therefore, sewage sludge can be efficiently applied as a raw material for the manufacturing of lightweight aggregates. The presented results confirm that a proper adjustment of composition allows easy the tailoring of aggregates’ performance and cost.
Manufacturing Parameters, Materials, and Welds Properties of Butt Friction Stir Welded Joints–Overview
- Aleksandra Laska
- Marek Szkodo
2020 Pełny tekst Materials
The modern and eco-friendly friction stir welding (FSW) method allows the combination of even such materials that are considered to be non-weldable. The development of FSW technology in recent years has allowed a rapid increase in the understanding of the mechanism of this process and made it possible to perform the first welding trials of modern polymeric and composite materials, the joining of which was previously a challenge. The following review work focuses on presenting the current state of the art on applying this method to particular groups of materials. The paper has been divided into subchapters focusing on the most frequently used construction materials, with particular emphasis on their properties, applications, and usage of the FSW method for these materials. Mechanisms of joint creation are discussed, and the microstructure of joints and the influence of material characteristics on the welding process are described. The biggest problems observed during FSW of these materials and potential causes of their occurrence are quoted. The influence of particular parameters on the properties of manufactured joints for each group of materials is discussed on the basis of a wide literature review.