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Search results for: ABNORMAL RETURNS
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The Response of Selected Domestic Capital Markets on the Development of COVID-19 Pandemic – a Broader View
PublicationObjective: The study examines how the record of the first, hundredth, thousandth, ten-thousandth, one-hundred-thousandth, and millionth cases of COVID-19 affected investor behaviour in capital markets. It also looks at whether the month in which the first case was recorded in a given market affected the direction and strength of investor reactions. Lastly, it verifies whether the two announcements made by the WHO related to COVID-19...
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Rapid dimension scaling of triple-band antennas by means of inverse surrogate modeling
PublicationGeometry scaling of antennas, i.e., finding optimum dimensions of the structure for given operating conditions and material parameters is an important yet challenging problem. In this paper, we discuss fast dimension scaling of triple-band antennas with respect to operating frequencies. We adopt the inverse surrogate modeling approach where the surrogate model is a function of the three operating frequencies of the antenna and...
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Numerical Test for Stability Evaluation of Discrete-Time Systems
PublicationIn this paper, a new numerical test for stability evaluation of discrete-time systems is presented. It is based on modern root-finding techniques at the complex plane employing the Delaunay triangulation and Cauchy's Argument Principle. The method evaluates if a system is stable and returns possible values and multiplicities of unstable zeros of the characteristic equation. For state-space discrete-time models, the developed test...
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How to model ROC curves - a credit scoring perspective
PublicationROC curves, which derive from signal detection theory, are widely used to assess binary classifiers in various domains. The AUROC (area under the ROC curve) ratio or its transformations (the Gini coefficient) belong to the most widely used synthetic measures of the separation power of classification models, such as medical diagnostic tests or credit scoring. Frequently a need arises to model an ROC curve. In the biostatistical...
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Comparing Arbitrary Unrooted Phylogenetic Trees Using Generalized Matching Split Distance
PublicationIn the paper, we describe a method for comparing arbitrary, not necessary fully resolved, unrooted phylogenetic trees. Proposed method is based on finding a minimum weight matching in bipartite graphs and can be regarded as a generalization of well-known Robinson-Foulds distance. We present some properties and advantages of the new distance. We also investigate some properties of presented distance in a common biological problem...
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Inwestycja w złoto – bezpieczna przystań, zabezpieczenie czy źródło dywersyfikacji dla polskiego inwestora
PublicationW artykule scharakteryzowano pojęcie inwestycji zabezpieczającej, dywersyfikującej oraz inwestycji określanej jako bezpieczna przystań. Celem opracowania jest zbadanie, czy występują powiązania między stopami zwrotu osiąganymi na polskim rynku akcji a stopami zwrotu z inwestycji w złoto. W pracy zweryfikowano hipotezę: stopa zwrotu z inwestycji w złoto spełnia funkcję inwestycji zabezpieczającej w długim okresie w stosunku do inwestycji...
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Balkan Stock Exchanges – Consideration of the Length of the Estimation Window in Similar Markets
PublicationPurpose: We study if capital markets in the Balkan are closely and positively related in terms of rate of return, risk, efficiency, and maximum cumulative loss in relation to different lengths of the estimation window. Design/Methodology/Approach: The research was carried out for the period from 01/01/2017 to 31/12/2019 using portfolio analysis. It was divided into an estimation window (01/01/2019 to 31/12/2019) and another with...
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Novel structure and size-reduction-oriented design of microstrip compact rat-race coupler
PublicationIn this paper, a novel structure of a miniaturized microstrip rat-race coupler has been proposed. Surrogate-based optimization procedures are applied to explicitly reduce the coupler size while maintaining equal power split at the operating frequency of 1 GHz and sufficient bandwidth for return loss and isolation characteristics. The optimization is performed using the objective function with four penalty components. The footprint...
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Extended duration running and impulse loading characteristics of an acoustic bearing with enhanced geometry
PublicationThis paper presents performance during prolonged running of the acoustic bearing when PZTs are switched off and when they are switched on. The effect of active PZT on shaft’s displacements in X and Y directions is clearly demonstrated. Performance of the acoustic bearing was also assessed when an impulse force was applied to the running shaft at speed. Once again the benefits of having PZTs active are beyond doubt. The instability...
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Parallel implementation of the DGF-FDTD method on GPU Using the CUDA technology
PublicationThe discrete Green's function (DGF) formulation of the finite-difference time-domain method (FDTD) is accelerated on a graphics processing unit (GPU) by means of the Compute Unified Device Architecture (CUDA) technology. In the developed implementation of the DGF-FDTD method, a new analytic expression for dyadic DGF derived based on scalar DGF is employed in computations. The DGF-FDTD method on GPU returns solutions that are compatible...
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Analiza skuteczności wybranych strategii kontrariańskich na warszawskiej GPW w latach 2014–2018
PublicationCapital multiplication is the main goal of investors and for many years they have been looking for methods and strategies that would enable them to achieve it to the greatest possible extent. Due to the fact that the expectations and characteristics of investors, including those concerning the investment period, are diverse, multiple strategies have emerged. One of such strategies, mainly long-term in nature, is the so-called...
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Novel Tools as New Challenges to HRM Communicational Practices (and the Increasingly Important Social Role of the Manager)
PublicationEach communicational process consists inseparably of three aspects: the linguistic (which means the whole language content of the message), technical (which states the form of the message) and the social (meaning social relations, emotions, behaviours). The recent COVID-19 pandemic deeply influenced several layers of our lives. But the main aim of this chapter is to focus on the communicational processes that normally take place...
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Optimizing the parameters of a small standalone hybrid power system
PublicationA hybrid power plant consists of renewable energy resources, an energy storage, a discharge load and an emergency power supply. Power plant parameters are tailored to meet the requirements of continuity of supply, cost minimization, return on investment period and system capacity utilization. The papaer presents the methodology for selecting power plant parameters with a larger number of decision criteria. The task is solved...
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Abdominal epilepsy in patient of schizophrenia - a diagnostic dilemma
PublicationAbdominal epilepsy is a rare and uncomman cause of recurrent abdominal pain. It is commonly occuring in children, but rarely in adolescent and elderly. Paroxysmal episodes of abdominal pain with neurological symptoms like dizziness, lethargy, and abnormal electroencephalogram and remarkable response to anticonvulsant confirms the diagnosis. Here we present a case of schizophrenia, who has repoted with recurrent abdominal pain...
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Hybrid Technique Combining the FDTD Method and Its Convolution Formulation Based on the Discrete Green's Function
PublicationIn this letter, a technique combining the finite-difference time-domain (FDTD) method and its formulation based on the discrete Green's function (DGF) is presented. The hybrid method is applicable to inhomogeneous dielectric structures that are mutually coupled with wire antennas. The method employs the surface equivalence theorem in the discrete domain to separate the problem into a dielectric domain simulated using the FDTD method...
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Wavelet Transform Analysis of Heart Rate to Assess Recovery Time for Long Distance Runners
PublicationThe diagnostics of the condition of athletes has become a field of special scientific interest and activity. The aim of this study was to verify the effect of a long (100 km) run on a group of runners, as well as to assess the recovery time that is required for them to return to the pre-run state. The heart rate (HR) data presented were collected the day before the extreme physical effort, on the same day as, but after, the physical...
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Technical and economic analysis of energy storage in the compressed air technology with low capacity for the production plant
PublicationCompressed air energy storage (CAES) system is a promising technology due to its numerous advantages, including relatively low maintenance cost, a long lifespan and high operational flexibility. This article explores the possibility of designing a CAES power plant as a source of electricity and heat for an existing industrial plant. The study involves the technical analysis of the power plant parameters and the economic analysis...
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Elliptical slot UWB monopole antenna
PublicationThe UWB monopole antenna with elliptical radiating slot end and microstrip feeding line terminated with radial stub have been designed, fabricated and measured. The antenna show return loss less than -12 dB in the whole UWB bandwidth. Linearity of the reflection coefficient phase product have also been achieved. Radiation patterns of the antenna measured at three selected frequency points indicated regular, approximately omni directional...
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Extending transition curve in analytical design method
PublicationThe paper presents the problem of extending the transitional curves, using for this purpose an analytical design method. The basis for the analysis of numerical calculations were carried out for a wide set of parameters characterizing the standard geometric system. We considered an importance of the size of radius of the circular arc and return angle of route on the obtained results after the formulation of appropriate theoretical...
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Selection of energy storage units by genetic algorithm for mitigating voltage deviations
PublicationIn recent years, energy storage units have become very popular. They are applied both for economic and technical purposes. Unfortunately, the cost of such devices is still high and selecting their proper location and rated power have to be performed precisely. In this paper, a Genetic-Algorithm-based optimization method for selecting the best configuration of energy storage units in the power network is proposed. The presented...
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Parametric analysis of Istanbul's Ring Road viaduct for three levels of seismic load
PublicationThe paper presents a numerical analysis of the Istanbul's ring road viaduct that is currently under construction within the Northern Marmara Highway project. The structure, due to its location on seismic prone areas is exposed to seismic loads of different magnitude and different return periods. The study is fo-cused on concrete bridge supports that are design to work in nonlinear range. The study, conducted in SOFISTIK environment,...
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Reduction of the Velocity Impact on the Magnetic Flux Leakage Signal
PublicationThe velocity effect on the magnetic flux leakage (MFL) signal was investigated in this paper. Experiments were performed for velocity of the MFL tool within the range of 0–2 m/s. The velocity was not constant during each measurement to imitate real operational conditions of the MFL tool. Two components of the leakage were measured, i.e. the tangential to the motion direction (x) and the normal to the investigated surface (z). In...
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Services Marketing Influence On Marketing Theory Evolution,
PublicationThe discovery of differences between tangible goods and services in the 1970s was one of the most landmark moments in the history of marketing with an emphasis being shifted to the need for using different/diversified marketing activities while dealing with various industries and types of products. The objective of this article is to briefly characterise the evolution of the marketing thought and to present the crucial influence...
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EFFECT OF ANTIOXIDANTS ON THE STABILITY OF PITCH- BASED POLYMER TO THERMO-OXIDATIVE ACTION
PublicationThe influence of stabilizers – hydrogen donors – on the processes of thermooxidative destruction of pitch-based polymer has been investigated. It is shown that Irganox has not stabilizing effect on pitch-based polymer and melamine slightly retards the destructive process. A mixture of melamine and Irganox exhibits synergetic stabilizing effect and at the optimum ratio it can be used to prevent unwanted thermooxidative processes...
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Parametric analysis of Istanbul's Ring Road viaduct for three levels of seismic load
PublicationThe paper presents a parametric analysis of the Istanbul's ring road viaduct that is currently under construction within the Northern Marmara Highway project. The structure, due to its location on seismic prone areas is exposed to seismic loads of different strengths and different return periods. The study is focused on concrete bridge supports that are design to work in nonlinear range. The parametric study, conducted in MATLAB...
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Method of identification of the slide tribological system top layer condition by assessment of the t-02 four-ball tester friction node operation
Publicationa method is proposed of the assessment of t-02 four-ball tester friction node operation during extreme unit loads on the tribological system for identification of the top layer condition in that system lubricated with the tested lubricating oil. by identification of the friction node with a thermodynamic system, that operation is treated as an energy generating process of the created servo-layer structure. the friction node operation...
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Bibliometric approach to tracking the concept of international competitiveness
PublicationThe main aim of paper is to identify the growth pattern in the international competitiveness literature, its core publications and key research domains on the basis of bibliometric data from the years 1945–2015. Citation data is collected from the ISI Web of Science Website, Scopus and Google Scholar, and analysed using HistCite, Pajek and VOSviewer software. Bibliometric indicators, network citation, key-route path methods and...
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EXCHANGE TRADED COMMODITIES AS A CATEGORY OF INNOVATIVE PRODUCTS ON EUROPEAN FINANCIAL MARKETS
PublicationThe article presents the main features of one category of innovative financial products – exchange traded commodities (ETCs) and results of the analysis of the European market for ETCs. ETCs are products listed and traded on the stock exchanges and they offer investors returns based on various assets (commodities or currencies). In contrast with the most widely recognized exchange traded funds (ETFs), ETCs are structured as debt...
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Analysis of dynamics of a map-based neuron model via Lorenz maps
PublicationModeling nerve cells can facilitate formulating hypotheses about their real behavior and improve understanding of their functioning. In this paper, we study a discrete neuron model introduced by Courbage et al. [Chaos 17, 043109 (2007)], where the originally piecewise linear function defining voltage dynamics is replaced by a cubic polynomial, with an additional parameter responsible for varying the slope. Showing that on a large...
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Funkcjonowanie zespołów napędu hydraulicznego maszyn w niskich temperaturach otoczenia
PublicationW pracy przedstawiono cztery warianty klasyfikacji rozruchów oziębionego napędu hydraulicznego. Pierwsza sytuacja dotyczy zagadnienia, w którym wszystkie zespoły układu napędowego wraz z olejem mają taką samą niską temperaturę podczas rozruchu. Pozostałe warianty odnoszą się do rozruchu w warunkach szoku termicznego wywołanych zasilaniem ciepłym czynnikiem roboczym oziębionych zespołów hydraulicznych. Rozruch zespołów...
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Rynek inwestowania w sztukę jako przykład inwestycji alternatywnej
PublicationW opracowaniu przedstawiono klasyfikację inwestycji emocjonalnych jako jednej z kategorii inwestycji alternatywnych. Ocenie poddano wpływ inwestorów chińskich na kondycję rynku sztuki. Zbadano zmienność stopy zwrotu dla wybranych krajowych rynków sztuki. Obliczono podstawowe miary statystyczne dla analizowanych inwestycji alternatywnych. Wskazano na potencjalne możliwości obniżenia ryzyka portfela inwestycyjnego poprzez odpowiednią...
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Discussion of “Stress-Displacement Response of Sand–Geosynthetic Interfaces under Different Volume Change Boundary Conditions” by Aliyeh Afzali-Nejad, Ali Lashkari, and Alejandro Martinez
PublicationThe influence of normal stiffness of interface on the interpretation of shear box tests
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Novel topology of compact coplanar waveguide resonant cell low-pass filter
PublicationIn this study, a novel pseudoelliptic function low-pass filter (LPF) constituted by a compact coplanar waveguide resonant cell has been designed and manufactured. The lumped-element seven-pole prototype has been adequately realized by using complementary perturbations located both in signal line and ground plane metallization. The fabricated uniplanar LPF offers a compact size of 5.6 x 9.8 mm2, return loss better than 26 dB over...
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Size Reduction of Microwave Couplers by EM-Driven Optimization
PublicationThis work addresses simulation-driven design optimization of compact microwave couplers that explicitly aims at circuit footprint area reduction. The penalty function approach allows us to minimize the area of the circuit while ensuring a proper power division between the output ports and providing a sufficient bandwidth with respect to return loss and isolation around the operating frequency. Computational cost of the optimization...
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High-Gain Compact Circularly Polarized X-Band Superstrate Antenna for CubeSat Applications
PublicationIn this letter, a concept of high-gain circularly polarized X-band antenna employing a partially reflecting surface (PRS) has been presented. In the initial antenna analysis, the influence of parasitic elements size in the PRS structure on antenna radiation pattern parameters has been investigated and the optimal arrangement of the elements has been identified. The proposed antenna provides wide bandwidth of return loss above 10...
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Evaluating Industry 4.0 Implementation Challenges Using Interpretive Structural Modeling and Fuzzy Analytic Hierarchy Process
PublicationThe fourth industrial revolution known as Industry 4.0 is reshaping and evolving the way industries produce products and individuals live and work therefore, gaining massive attraction from academia, business and politics. The manufacturing industries are optimistic regarding the opportunities Industry 4.0 may offer such as, improved efficiency, productivity and customization. The present research contributes to the Industry 4.0...
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Future Skills and Education in a Computerized World
PublicationAs computerization of Western economies has advanced, the supply of the demand for routine cognitive tasks and routine manual tasks has fallen. Computerization has increased labour input of nonroutine cognitive tasks which has favourized high educated workers. Similarly, there is clear evidence of an increase in demand for high skilled workforce which originates from poor machine performance of nonroutine...
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Constant-Factor Approximation Algorithm for Binary Search in Trees with Monotonic Query Times
PublicationWe consider a generalization of binary search in linear orders to the domain of weighted trees. The goal is to design an adaptive search strategy whose aim is to locate an unknown target vertex of a given tree. Each query to a vertex v incurs a non-negative cost ω(v) (that can be interpreted as the duration of the query) and returns a feedback that either v is the target or the edge incident to v is given that is on the path towards...
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Kształtowanie wartości wskaźników wspomagania finansowego przez przedsiębiorstwa z sektora MSP w zależności od osiąganej rentowności aktywów
PublicationW artykule przedstawiono różnice w sposobie kształtowania wartości wskaźników z obszaru wspomagania finansowego pomiędzy przedsiębiorstwami z sektora MSP w zależności od osiąganego przez nie poziomu rentowności aktywów. W trakcie przeprowadzonych badań uwzględniono 109 174 sprawozdania finansowe przedsiębiorstw, prowadzących działalność gospodarczą w 27 różnych działach gospodarki narodowej. Do potwierdzenia zróżnicowania wspomagania...
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Human Factors and Functional Safety Analysis in Designing the Control Rooms of Industrial Hazardous Plants
PublicationIn this work some aspects of human factors and functional safety analysis in designing the control rooms of industrial hazardous plants are presented. The “defence in depth” (D-in-D) concept is outlined. Some designing issues of the alarm system (AS) with regard to human factors to be supported using the human reliability analysis (HRA) are discussed. The AS and decision support system (DSS), when properly designed, would contribute...
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A CNN based coronavirus disease prediction system for chest X-rays
PublicationCoronavirus disease (COVID-19) proliferated globally in early 2020, causing existential dread in the whole world. Radiography is crucial in the clinical staging and diagnosis of COVID-19 and offers high potential to improve healthcare plans for tackling the pandemic. However high variations in infection characteristics and low contrast between normal and infected regions pose great challenges in preparing radiological reports....
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Usability and relational factors in user-perceived quality of online services
PublicationThe purpose of this paper is to identify the key determinants of con-sumer-perceived usability of online service websites and their impact on e-loyalty potential, expressed by customer’s willingness to return and to recommend the website to others. In this experimental usability study fifteen video-recorded users performed specific tasks in financial, travel and health online service websites. After completing the tasks users filled...
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Wideband Highly-Selective Bandpass Filtering Branch-Line Coupler
PublicationThis paper presents a novel design of a wideband highly-selective bandpass filtering branch-line coupler (FBLC). By integrating a coupled microstrip line, and an open-ended stub at each port of a single-section BLC, bandpass filtering characteristics with excellent selectivity and broad operating bandwidth have been achieved. The proposed circuit has been verified through EM simulations and physical measurements of the fabricated...
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Position Estimation in Corridors Along the Coupled Mode of Radiating Cables
PublicationRadiating cables are mostly used to provide radio communication in tunnels or corridors, but they can also be used to estimate the position of a mobile terminal along the cable. In this paper, a measuring receiver’s position was estimated by measuring the difference in the direct signal’s reception time, which was generated by a transmitter connected to one end of the radiating cable, and the delayed signal retransmitted from another...
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Kształtowanie wartości wskaźników płynności finansowej przez przedsiębiorstwa z sektora MSP w zależności od osiąganej rentowności aktywów
PublicationW artykule przedstawiono różnice w sposobie kształtowania wartości wskaźników z obszaru płynności finansowej pomiędzy przedsiębiorstwami z sektora MSP w zależności od osiąganego przez nie poziomu rentowności aktywów. W trakcie przeprowadzonych badań uwzględniono 109 174 sprawozdania finansowe przedsiębiorstw, prowadzących działalność gospodarczą w 27 różnych działach gospodarki narodowej. Do potwierdzenia zróżnicowania płynności...
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O zbieżności rozwiązań w nieliniowym mikropolarnym ośrodku sprężysto-plastycznym - zastosowanie elementów skończonych wyższego rzędu.
PublicationEfekty lokalizacji w nieliniowym geometrycznie sprężysto-plastycznym mikropolarnym ośrodku z osłabieniem materiału. Hipotezy Hubera-Misesa-Hencky’ego i Druckera-Pragera. Rozwiązanie równań sprężysto-plastycznych przy użyciu algorytmu powrotnego. Opis zastosowanych elementów skończonych. Przykłady numeryczne obliczeń w geotechnice.
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Effect of vehicle motion stability after impact/crash on traffic safety
PublicationThe article presents the application of general stability theory to the study of road traffic stability immediately after an impact (crash, collision). It turns out that when modelling a collision, vehicles can be treated as colliding masses and dynamical systems can be assigned to this phenomenon.
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Multibody models for gait analysis
PublicationThe aim of this study was to create multibody biomechanical models to analyze a normal gait of the human. Proposed models can be used to identify joint moments of the lower limbs during normal gait in the single and double support phases. Applying Newton-Euler formulation, following planar models were developed: 1) a mathematical 6DOF model describing a gait in the sagittal plane of the body for single support phase and double...
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Ultra-Wideband Vivaldi Antenna with an Integrated Noise-Rejecting Parasitic Notch Filter for Online Partial Discharge Detection
PublicationPower transformers and gas-insulated switchgear (GIS) play crucial roles in electrical power grids. However, they may suffer from degradation of insulation material due to wear and tear, leading to their imminent failure. Partial discharges (PDs) are an initial sign of insulation materials degradation which emit signals spanning various physical domains, including electromagnetic. PDs are temporally narrow, high-frequency, stochastic...
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Kształtowanie poziomu wskaźników sprawności działania przez przedsiębiorstwa z sektora MSP w zależności od osiąganej rentowności aktywów
PublicationW artykule przedstawiono różnice w kształtowaniu poziomów wskaźników z obszaru sprawności działania pomiędzy przedsiębiorstwami z sektora MSP w zależności od osiąganej przez nie rentowności aktywów. W trakcie przeprowadzonych badań uwzględniono 34.820 sprawozdania finansowe przedsiębiorstw, prowadzących działalność gospodarczą w 22 różnych działach gospodarki narodowej. Do potwierdzenia zróżnicowania sprawności działania przedsiębiorstw...