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Search results for: STABILITY ANALYSIS, DISCRETE-TIME SYSTEMS, FRACTIONAL-ORDER SYSTEMS
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On the Structure of Time in Computational Semantics of a Variable-Step Solver for Hybrid Behavior Analysis
PublicationHybrid dynamic systems combine continuous and discrete behavior. Often, computational approaches are employed to derive behaviors that approximate the analytic solution. An important part of this is the approximation of differential equation behavior by numerical integration. The accuracy and computational efficiency of the integration usually depend on the complexity of the method and its implicated approximation errors, especially...
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Camera sabotage detection for surveillance systems
PublicationCamera dysfunction detection algorithms and their utilization in realtime video surveillance systems are described. The purpose of using the proposed analysis is explained. Regarding image tampering three algorithms for focus loss, scene obstruction and camera displacement detection are implemented and presented. Features of each module are described and certain scenarios for best performance are depicted. Implemented solutions...
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Analysis of temporary steel grandstand with different bracing systems exposed to crowd load
PublicationGrandstands are structures which are regularly subjected to dynamic loads generated by crowd motions. It is a dangerous situation when spectators induce rhythmic jumping, dancing, stamping, etc. If the synchronized movement of spectators excites a natural frequency of the structure, resonant response might occur. To avoid such situations, temporary steel grandstands are commonly strengthened using additional elements that create...
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Water hammer analysis in water supply systems
PublicationPrzedstawiono metodę analizy zjawiska uderzenia hydraulicznego w sieci pierścieniowej. Model matematyczny opisano za pomocą układu równań różniczkowych cząstkowych I stopnia, które przekształcono do układu równań zwyczajnych. Dla rozwiązania układu równań zastosowano metodę predykator-korektor. Podano odpowiednie równania różnicowe dla węzłów złożonych. Przedstawiono przykład obliczeniowy sieci wodociągowej pierścieniowej, składającej...
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An integrated analysis of protection layers in hazardous systems
PublicationGłównym tematem niniejszej publikacji jest dyskusja nad wybranymi zagadnieniami związanymi z analizą bezpieczeństwa funkcjonalnego infrastruktury krytycznej oraz obiektów podwyższonego ryzyka. Problematyka bezpieczeństwa funkcjonalnego związana jest z międzynarodowymi normami IEC 61508 oraz IEC 61511. W artykule przedstawiono problematykę zintegrowanej oceny bezpieczeństwa funkcjonalnego wraz z uwzględnieniem analizy warstw zabezpieczeń...
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Harmonic Analysis Of Electrochemical and Corrosion Systems - A Review
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Losses and energy efficiency of drive motors and systems
PublicationLosses and energy efficiency of every drive motor must be presented as functions of physical quantities independent of losses in the motor. Such quantities are speed and load required by the machine or device driven by the motor, changing in the drive operating field. Speed and load of the motor decide of the instantaneous useful power of the motor and also in a differentiated way of kinds and values of losses occurring in the...
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Losses and energy efficiency of drive motors and systems
PublicationLosses and energy efficiency of every drive motor must be presented as functions of physical quantities independent of losses in the motor. Such quantities are speed and load required by the machine or device driven by the motor, changing in the drive operating field. Speed and load of the motor decide of the instantaneous useful power of the motor and also in a differentiated way of kinds and values of losses occurring in the...
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Geotechnical Analysis and Stability Assessment of a Landslide Event in Gera Woreda, Ethiopia
PublicationThis study investigates the geotechnical factors influencing a recent landslide event in Gera Woreda, Ethiopia. The primary objective was to identify the soil properties contributing to landslide occurrence and understand the triggering mechanisms. Field investigations, soil sampling from both affected and unaffected areas, and subsequent laboratory characterization were conducted. The analysis revealed a dominance of fine-grained...
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Numerical Model of Surface and Quasi-Spherical Sea Noise and Its Application to Analysis of DIFAR Systems
PublicationVarious types of passive sonar systems are used to detect submarines. These activities are complex and demanding. Therefore, computer simulations are most often used at the design stage of these systems. For this reason, it is also necessary to simulate the acoustic ambient noise of the sea. The article proposes a new numerical model of surface and quasi-spherical sea noise and presents its statistical parameters. The results of...
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Research on GNSS satellite navigation systems
PublicationThis article contains results of research on two GNSS systems, i.e. GPS and GLONASS. Architectures, signal structures and navigation messages of both systems have been described. Some selected investigation results, concerning receiver performance in presence of interference, have been presented.
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Adaptive Dynamical Systems Modelling of Transformational Organizational Change with Focus on Organizational Culture and Organizational Learning
PublicationTransformative Organizational Change becomes more and more significant both practically and academically, especially in the context of organizational culture and learning. However computational modeling and a formalization of organizational change and learning processes are still largely unexplored. This paper aims to provide an adaptive network model of transformative organizational change and translate a selection of organizational...
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Nonnegative solutions to nonlocal boundary value problems for systems of second-order differential equations dependent on the first-order derivatives
PublicationStosując tw. Avery-Petersona o punkcie stałym, podano warunki dostateczne na istnienie nieujemnych rozwiązań dla układów równań różniczkowych rzędu drugiego z argumentami opóźnionymi i wyprzedzonymi oraz warunkami brzegowymi zawierającymi całki Stieltjesa. Praca zawiera wiele przykładów.
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METHOD OF TRAINING THE ENDOSCOPIC VIDEO ANALYSIS ALGORITHMS TO MAXIMIZE BOTH ACCURACY AND STABILITY
PublicationIn the article a new training and testing method of endoscopic video analysis algorithms is presented. Classical methods take into account only eciency of recognizing objects on single video frames. Proposed method additionally considers stability of classiers output for real video input. The method is simple and can be trained on data sets created for other solutions. Therefore, it is easily applicable to existing endoscopic video...
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A new look at the statistical identification of nonstationary systems
PublicationThe paper presents a new, two-stage approach to identification of linear time-varying stochastic systems, based on the concepts of preestimation and postfiltering. The proposed preestimated parameter trajectories are unbiased but have large variability. Hence, to obtain reliable estimates of system parameters, the preestimated trajectories must be further filtered (postfiltered). It is shown how one can design and optimize such...
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The guidelines and principles for planning and design of road restraint systems
PublicationThe project RID 3A Road Safety Equipment (RoSE) implemented by the Gdansk University of Technology within the RID programme, aims to conduct a comprehensive study and analyses of different vehicle containment systems (PN-EN 1317) and types of support structures (PN-EN 12767) and their performance. Within the project an analysis will be conducted of available research reports...
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Compact scheduling of zero–one time operations in multi-stage systems
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Designing optimal and safe control strategies for time-varying dynamical systems
PublicationPublikacja opisuje metodę projektowania optymalnej trajektorii punktu pracy w czasoprzestrzeni stanów przy wykorzystaniu algorytmów optymalizacji grafowej. Zakłada się deterministyczny charakter zmian dynamiki rozpatrywanego procesu. Przestrzeń robocza, będąca ograniczonym podzbiorem czasoprzestrzeni stanów, jest dzielona na zbiór segmentów, którym przypisywane są wielkości reprezentujące właściwości dynamiki własnej w obrębie...
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Computational Model of Time for Stiff Hybrid Systems Applied to Control Synthesis
PublicationComputational representation.
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Compact scheduling of zero-one time operations in multi-stage systems.
PublicationRozważamy szeregowanie zwarte na maszynach dedykowanych z zero-jedynkowymi operacjami w modelu otwartym, przepływowym i mieszanym. Harmonogramy zostały zmodelowane przy pomocy pokolorowań krawędzi grafu konfliktów z pewnymi dodatkowymi ograniczeniami. Dowodzimy NP-trudności problemów w przypadku ogólnym oraz prezentujemy przegląd znanych wielomianowych algorytmów szeregujących dla systemów o specyficznej budowie.
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Decoupled Kalman filter based identification of time-varying FIR systems
PublicationWhen system parameters vary at a fast rate, identification schemes based on model-free local estimation approaches do not yield satisfactory results. In cases like this, more sophisticated parameter tracking procedures must be used, based on explicit models of parameter variation (often referred to as hypermodels), either deterministic or stochastic. Kalman filter trackers, which belong to the second category, are seldom used in...
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Analysis of positioning methods using Global Navigation Satellite Systems (GNSS) in Polish State Railways (PKP)
PublicationEach year, global navigation satellite systems (GNSS) improve their accuracy, availability, continuity, integrity, and reliability. Due to these continual improvements, the systems are increasingly used in various modes of transport, including rail transport, the subject of this publication. GNSS are used for rail passenger information, rail traffic management, and rail traffic control. These applications differ in the positioning...
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A convergence result for mountain pass periodic solutions of perturbed Hamiltonian systems
PublicationIn this work, we study second-order Hamiltonian systems under small perturbations. We assume that the main term of the system has a mountain pass structure, but do not suppose any condition on the perturbation. We prove the existence of a periodic solution. Moreover, we show that periodic solutions of perturbed systems converge to periodic solutions of the unperturbed systems if the perturbation tends to zero. The assumption on...
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Origami Antennas for Wireless Communication Systems
PublicationThis book discusses the lightweight, reconfigurable, and deployable origami antennas for adaptive communication systems. Traditional antennas, with their fixed characteristics, struggle to meet the evolving needs of modern communication systems. Reconfigurable antennas, on the other hand, can dynamically adjust their operating parameters, offering significant advantages in terms of performance, size, and cost. Origami technology...
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On noncausal identification of nonstationary stochastic systems
PublicationIn this paper we consider the problem of noncausal identification of nonstationary,linear stochastic systems, i.e., identification based on prerecorded input/output data. We show how several competing weighted least squares parameter smoothers, differing in memory settings, can be combined together to yield a better and more reliable smoothing algorithm. The resulting parallel estimation scheme automatically adjusts its smoothing...
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Utilising IT-based systems in regatta management
PublicationThe development and increasing accessibility of new technologies has brought changes to the management of sailing regattas. Organisational and promotional difficulties faced by the organisers are now being tackled with software-based systems. This article considers various information technology (IT) systems, designed to support the organisation and presentation of sailing regattas and explores how they are perceived by regatta...
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On the existence of homoclinic type solutions of inhomogenous Lagrangian systems
PublicationWe study the existence of homoclinic type solutions for a class of inhomogenous Lagrangian systems with a potential satisfying the Ambrosetti-Rabinowitz superquadratic growth condition and a square integrable forcing term. A homoclinic type solution is obtained as a limit of periodic solutions of an approximative sequence of second order differential equations.
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Verification of a Novel Method of Detecting Faults in Medium-Voltage Systems with Covered Conductors
PublicationThis paper describes the use of new methods of detecting faults in medium-voltage overhead lines built of covered conductors. The methods mainly address such faults as falling of a conductor, contacting a conductor with a tree branch, or falling a tree branch across three phases of a medium-voltage conductor. These faults cannot be detected by current digital relay protection systems. Therefore, a new system that can detect the...
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Testbed for development and verification of hybrid localization systems
PublicationIn this paper a testbed for development and verification of hybrid localization systems is presented. It allows for systematic analysis of hybrid localization methods and speed up the development of new schemes. The proposed testbed platform is composed of subsystem for sequential data collection and testing infrastructure that can be used for investigating the localization mechanisms in controllable environment.
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Towards automation of IT systems repairs
PublicationMonitoring and repair are two sides of the on-the-fly maintenance of IT systems.Monitoring is well supported by automatic tools. In contrast, repairs involve much higherhuman intervention which negatively affects reliability and efficiency. The paper intro-duces a method of automating repairs of IT systems which can be integrated with any ofthe existing monitoring mechanisms. The method is described as a collection of modelsand...
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Metaheuristic algorithms for optimization of resilient overlay computing systems
PublicationThe idea of distributed computing systems has been gaining much interest in recent years owing to the growing amount of data to be processed for both industrial and academic purposes. However, similar to other systems, also distributed computing systems are vulnerable to failures. Due to strict QoS requirements, survivability guarantees are necessary for provisioning of uninterrupted service. In this article, we focus on reliability...
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Alternative Energy: Photovoltaic Modules and Systems
PublicationUse of solar energy does not contribute to global warming. The light-to-current conversion (photovoltaic conversion) takes place within solar cells, which in most cases are made of silicon. Solar module consists of many solar cells, which are electrically connected and placed between glass or Tedlar® and framed by an aluminium frame. A number of solar modules and other components form photovoltaic systems. In this entry, a brief...
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Semantic Integration of Heterogeneous Recognition Systems
PublicationComputer perception of real-life situations is performed using a variety of recognition techniques, including video-based computer vision, biometric systems, RFID devices and others. The proliferation of recognition modules enables development of complex systems by integration of existing components, analogously to the Service Oriented Architecture technology. In the paper, we propose a method that enables integration of information...
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Studies of the Interaction Dynamics in Albumin-Chondroitin Sulfate Systems by Recurrence Method
PublicationThe physicochemical basis of lubrication of articular cartilage is still not fully understood. However, the synergy between components of the synovial fluid can be a crucial factor that could explain this phenomenon. This work presents a nonlinear data analysis technique named the recurrence method, applied to the system involving two components of synovial fluid: albumin and chondroitin sulfate (CS) immersed in a water environment....
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Hybrid, Approximate Models of Distributed-Parameter Systems
PublicationThe paper introduces the method of distributed-parameter systems modelling. It enables to obtain low order modal model of the system that experiences Coriolis acceleration component and gyroscopic effect. In such cases, corresponding system equations are non-self-adjoined. To solve this problem modal reduced model is built up for the system without Coriolis acceleration or gyroscopic effect terms. These phenomena are next included...
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Pawlak's flow graph extensions for video surveillance systems
PublicationThe idea of the Pawlak's flow graphs is applicable to many problems in various fields related to decision algorithms or data mining. The flow graphs can be used also in the video surveillance systems. Especially in distributed multi-camera systems which are problematic to be handled by human operators because of their limited perception. In such systems automated video analysis needs to be implemented. Important part of this analysis...
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Approaching Secure Industrial Control Systems
PublicationThis study presents a systematic approach to secure industrial control systems based on establishing a business case followed by the development of a security programme. To support these two fundamental activities the authors propose a new method for security cost estimation and a security assessment scheme. In this study they explain the cost evaluation technique and illustrate with a case study concerning the assessment of the...
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Application of BAN Network to Increase Security in Transport Systems
PublicationIn the article general characteristics of the BAN network with M2M communications are presented. These are networks that enable the implementation of wireless transmission of signals using special sensors located on the body or implanted subcutaneously. These sensors allow monitoring of different type life parameters of a human. In the next part of work there is proposed the implementation of BAN networks to transport systems as...
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EFFICIENCY OF HEALTHCARE SYSTEMS IN EUROPEAN COUNTRIES - THE DEA NETWORK APPROACH
PublicationHealthcare systems in Europe are constantly undergoing reforms which adapt them to social, economic and political requirements. The aim of this article is to examine the efficiency of healthcare systems in 30 European countries in 2014. The Network Data Envelopment Analysis (NDEA) model was used. The efficiency of the countries’ overall health systems and their two main components were examined: the public health system and the...
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Current divider-based nanosecond high current pulse measuring systems
PublicationThis paper presents the analysis of the new approach to the measurement methodology of significant values (in order of hundreds of kA) and huge steepness (in order of MA/μs) current pulses based on current dividers along with a comparison of the various types transducers suitability in measuring systems with such extreme parameters. Such dividers are used to extend the measurement ranges of current transducers with limited current...
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Modelling method for a class of distributed-lumped parameter systems
PublicationThe paper presents an alternative approach for modelling and order reduction of continuous system. The proposed methodology combines application of two methods: the modal decomposition method and the rigid finite element method. The given continuous structure is divided into 1D continuous substructures. For each 1D substructure modal decomposition and reduction procedure is applied. Interactions between substructures are described...
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Event driven MPC for networked control systems
PublicationBecause of variable delays and stochastic data packets loss networked control systems require suitable algorithms to ensure stability of the control system and guarantee desired control performance. This paper presents the idea of an event driven approach with MPC controller. In opposition to network compensation, where standard regulators are used, the presented solution integrates network with plant. A MPC based controller is...
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The use and development of e-learning systems in educational projects
PublicationThe article introduces the problem of usage and development of e-learning systems among Polish universities. Easily accessible internet and IT development led to changes in education. Through the use of IT tools, e-learning has become an increasingly popular form of education. Presently, majority of Polish universities use an e-learning system of their own choosing designed to support the didactic processes. The goal of the article...
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Knowledge processing methodologies in intelligent autonomous systems
PublicationPrzedstawiono najnowsze trendy oraz stan badań światowych w zakresie wspomagania procesów zarządzania wiedzą w inteligentnych systemach autonomicznych.
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Port-Based Modelling of Distributed-Lumped Parameter Systems
PublicationThere in the paper is presented an uniform, port-based approach to modelling of both lumped and distributed parameter systems. Port-based model of the distributed system has been defined by application of bond graph methodology and distributed transfer function method (DTFM). The approach proposed combines versatility of port-based modelling and accuracy of distributed transfer function method. The concise representation of lumped-distributed...
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Integration of natural and artificial intelligence in production systems
PublicationIntegration processes play an increasingly important role in modern economy, and seriously co-decide about the effectiveness of the company. Integration phase occurs in the system life cycle by preceding the final stages of its implementation and activation. In turn, used in software engineering (SE) iteration-evolutionary models, such as spiral model make that the integration activities can occur in varying degrees in all phases...
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Analytical modeling of electric drives for vehicle traction control systems
PublicationWheel-torque control bandwidth in vehicle dynamics model is crucial in evaluating optimal tracking ability of tire slip and in analysis of control system stability. Electric drives’ control dynamics are influenced by timing of digital control events, e.g. by sampling instant of motor currents. Reflecting this timing in drive analytical models is therefore important for analysis of vehicle traction systems. The paper considers five...
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Porous Phantoms Mimicking Tissues—Investigation of Optical Parameters Stability Over Time
PublicationOptical phantoms are used to validate optical measurement methods. The stability of their optical parameters over time allows them to be used and stored over long-term periods, while maintaining their optical parameters. The aim of the presented research was to investigate the stability of fabricated porous phantoms, which can be used as a lung phantom in optical system. Measurements were performed in multiple series with an interval...
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Fuel systems of high power stationary engine
PublicationThe use of alternative fuels and, in the future, synthetic fuels has forced changes in the design of fuel supply systems in internal combustion engines. When operating a stationary engine at constant load, the possibility of using lean fuel mixtures appears. The selection of a precise operating mixture ignition system requires changes in traditional fuel systems. The article presents the current designs of fuel supply systems and...
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ANALYSIS OF BRACE STIFFNESS INFLUENCE ON STABILITY OF THE TRUSS
PublicationThe paper is devoted to the numerical and experimental research of stability of a truss with side elastic supports at the top chord. The structure is a model of a real roof truss scaled by factor ¼. The linear buckling analysis and non-linear static analysis were carried out. The buckling length factor for the compressed top chord was calculated and the limit load for the imperfect truss shell model with respect to brace stiffness...