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Wyniki wyszukiwania dla: KNOWLEDGE GRID
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Charakterystyka środowiska Knowledge Grid
PublikacjaZorganizowanie wiedzy zgromadzonej w Internecie to współcześnie ważne zagadnienie badawcze. Artykuł opisuje środowisko Knowledge Grid i mechanizmy jego działania. Wiedza przechowywana w Knowledge Grid może zostać zorganizowana w trójwymiarową strukturę. Opracowany został również Knowledge Grid Operating Language, który jest językiem służącym do operowania na danych udostępnianych w tym środowisku. Za jego pomocą możliwe jest umieszczenia...
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Knowledge-Grid Modelling for Academic Purposes
PublikacjaNowadays, we face a huge amount of data and information sharing on the Web by different users worldwide. A multidimensional perspective in describing a university ontology seems to be very important for the modelling of higher education resources. This paper proposes a multi-dimensional knowledge model, designed to distribute and manage knowledge resources efficiently. We propose our model as the foundation of an advanced knowledge...
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Toward knowledge-grid model for academic purposes
PublikacjaNowadays we face a huge amount of data and information sharing on the Web by different users worldwide. For example, the academic environment is one of such places where teachers share and manage knowledge for groups of students. This paper proposes a multi-dimensional knowledge space model, designed to distribute and manage knowledge resources efficiently. We view our model as a foundation of a knowledge grid platform. Two crucial...
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Automatic evaluation of information credibility in Semantic Web and Knowledge Grid
PublikacjaThis article presents a novel algorithm for automatic estimation of information credibility. It concerns information collected in Knowledge Grid and Semantic Web. Possibilities to evaluate the credibility of information in such structures are much greater than those available for WWW sites which use natural language. The rating system presented in this paper estimates credibility automatically on the basis of the following metrics:...
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Quality Modeling in Grid and Volunteer-Computing Systems
PublikacjaA model of computational quality in large-scale computing systems was presented in the previous chapter of this book. This model describes three quality attributes: performance, reliability and energy efficiency. We assumed that all processes in the system are incessantly ready to perform calculations and that communication between the processes occurs immediately. These assumptions are not true for grid and volunteer computing...
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Engineering education for smart grid systems in the quasi-industrial environment of the LINTE^2 laboratory
PublikacjaSmart grid systems are revolutionising the electric power sector, integrating advanced technologies to enhance efficiency, reliability and sustainability. It is important for higher education to equip the prospective smart grid professional with the competencies enabling them to navigate through the related complexities and drive innovation. To achieve this, interdisciplinary education programmes are necessary, addressing inter...
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JUST CULTURE MATURITY QUESTIONNAIRE VALIDATION IN A POLISH HOSPITAL
PublikacjaPurpose: (To present the results of the statistical validation of just culture maturity questionnaire (JCMQ), used to recognize the maturity level of JC among nurses in the hospital in Poland. Methodology: (The case study and 5-stage research with the use of a 5-point Likert scale questionnaire with 28 statements, distributed among nurses. The results were statistically processed with Statistica 13.1 software. Findings: We confirmed...
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On-line Search in Two-Dimensional Environment
PublikacjaWe consider the following on-line pursuit-evasion problem. A team of mobile agents called searchers starts at an arbitrary node of an unknown network. Their goal is to execute a search strategy that guarantees capturing a fast and invisible intruder regardless of its movements using as few searchers as possible. We require that the strategy is connected and monotone, that is, at each point of the execution the part of the graph...
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Comparison of strain results at a laser weld notch obtained by numerical calculations and experimental measurements
PublikacjaIn the development of ship structures applying new materials and it’s purposeful placement play an important role. During the last years, especially in a construction of ro-ro type vessels, the usage of novel sandwich structures in cargo decks is profitable. Steel sandwich panel is an innovative solution which at a todays state of development can be used for the construction of any members not taking part in a global bending of...
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Experience based knowledge representation for Internet of Things and Cyber Physical Systems with case studies
PublikacjaCyber Physical Systems and Internet of Things have grown significant attention from industry and academia during the past decade. The main reason behind this interest is the capabilities of such technologies to revolutionize human life since they appear as seamlessly integrating classical networks, networked objects and people to create more efficient environments. However, enhancing these technologies with intelligent skills becomes...
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Voltage Conditions in Low Voltage Grid with Connected Mictogeneration
PublikacjaThe introduction of distributed generation into a low voltage grid may cause voltage problems in it. The paper discusses the effect of microgeneration on voltage levels in a low voltage grid. A real low voltage grid of considerable length was selected for the analysis. The grid primarily supplies residential buildings in a rural area. Results of tests that consider potential measures which could be applied in this grid to improve...
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Comprehensive compensation of grid current distortion by shunt active power filters
PublikacjaThe paper presents a comprehensive approach to the compensation of grid current distortion in shunt active power filter systems. Four sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, time delays in the evaluation of grid voltages and computation of compensating currents, fluctuations of the dc bus voltage, and the distortion of inverter output voltages due...
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Data Model Development for Security Information Sharing in Smart Grids
PublikacjaThe smart grid raises new security concerns which require novel solutions. It is commonly agreed that to protect the grid, the effective collaboration and information sharing between the relevant stakeholders is prerequisite. Developing a security information sharing platform for the smart grid is a new research direction which poses several challenges related to the highly distributed and heterogeneous character of the grid. In...
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Security information sharing for smart grids: Developing the right data model
PublikacjaThe smart grid raises new security concerns which require novel solutions. It is commonly agreed that to protect the grid the effective collaboration and information sharing between the relevant stakeholders is prerequisite. Developing a security information sharing platform for the smart grid is a new research direction which poses several challenges related to the highly distributed and heterogeneous character of the grid. In...
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Comprehensive distortion compensation of grid-connected inverter currents
PublikacjaThe paper presents a comprehensive approach to the compensation of phase current distortion of grid-connected power inverters. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, voltage fluctuations in the dc link, time delays in the estimation of grid voltages, and the distortion of inverter output voltages due to dead-time effects and related...
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High Frequency Conducted Emission in AC Motor Drives Fed By Frequency Converters: Sources and Propagation Paths
PublikacjaProvides a concise and thorough reference for designing electrical and electronic systems that employ adjustable speed drives Electrical and electronic systems that employ adjustable speed drives are being increasingly used in present-day automation applications. They are considered by many application engineers as one of the most interfering components, especially in a contemporarily faced industrial environment. This book fills...
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Compensation of Dead Time Effects for Shunt Active Power Filters
PublikacjaThe paper presents a comprehensive approach to the compensation of the grid current distortion for shunt active power filter systems. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, time delays in the estimation of compensating currents and grid voltages, fluctuations of the dc bus voltage, and the distortion of inverter output voltages due...
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Mersenne Number Finding and Collatz Hypothesis Verification in the Comcute Grid System
PublikacjaIn this chapter, some mathematic applications have been described to test scalability of the Comcute grid system. Especially, a verification of the Collatz hypothesis and finding Mersenne numbers were applied to prove the scalability and high performance of this grid system. Results were compared with outcomes obtained by the other grid systems.
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Simplified Distribution Grid Modelling for Connection Analyses
PublikacjaThis paper considers the modelling of medium and low voltage grids for the purpose of connection studies by distribution grid operators. Possible simplifications in grid modelling are discussed, which are acceptable from the viewpoint of the final result. The main driver of the modelling simplification is the MS Excel environment used as the computation platform, and the limitation of time for grid modelling.
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Volunteer Computing System Comcute with Smart Scheduler
PublikacjaIn this paper, a volunteer grid called Comcute is studied. Moreover, the harmony search scheduler is proposed. This scheduler has been designed for efficient using some resources of volunteer grid. The harmony search scheduler optimizes both a workload of a bottleneck computer and the cost of grid. Finally, some experiment outcomes have been discussed.
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Application of Doubly Connected Dominating Sets to Safe Rectangular Smart Grids
PublikacjaSmart grids, together with the Internet of Things, are considered to be the future of the electric energy world. This is possible through a two-way communication between nodes of the grids and computer processing. It is necessary that the communication is easy and safe, and the distance between a point of demand and supply is short, to reduce the electricity loss. All these requirements should be met at the lowest possible cost....
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Induction Generator with Direct Control and a Limited Number of Measurements on the Side of the Converter Connected to the Power Grid
PublikacjaThe article presents an induction generator connected to the power grid using the AC/DC/AC converter and LCL coupling filter. Three-level inverters were used in the converter, both from the generator side and the power grid side. The algorithm realizing Pulse Width Modulation (PWM) in inverters has been simplified to the maximum. Control of the induction generator was based on the Direct Field-Oriented Control (DFOC) method. At...
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Enhancing Security of Advanced Metering Infrastructure by Introducing Threshold Attendance Protocol
PublikacjaThe industry pushes towards smart grid systems in order to resolve current limitations of the unidirectional legacy power grid infrastructure. By introducing Advanced Metering Infrastructure (AMI) as an integral part of the smart grid solution, the utility company obtains an invaluable tool to optimize its network, lower the operational costs, and improve quality of service. Unfortunately, introducing two-way communication poses...
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Power converter interface for urban DC traction substations - solutions and functionality.
PublikacjaThis paper focuses on extending an urban DC traction substation functionality by means of an additional power converter interface (PCI). In particular, by enabling bidirectional energy exchange between LV DC traction grid, AC grid and V2G chargers. Among other things, the presented material compares general attributes of the most promising DC/DC converters that can be used in a PCI, meet the requirements of galvanic isolation and...
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MONITORING SYSTEM OF THE ROAD EMBANKMENT
PublikacjaThe paper presents the analysis of the monitoring system of the embankment supported on concrete columns and overlaid by a load transfer platform with the embedded steel grid. This field investigation was to study the complex interaction among the columns, the load transfer platform layer, and steel grid via in situ measurements during erection and live loading of the embankment. The study was focused on the behaviour of steel...
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Prof. Haitham Abu-Rub - A Visit to Poland's Gdansk University of Technology
PublikacjaReport on visit of Prof. Haitham Abu-Rub in Gdansk University of Technology. Speech on the Smart Grid Centre. Visit in the new smart grid laboratory of the GUT, the Laboratory for Innovative Power Technologies and Integration of Renewable Energy Sources (LINTE^2).
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Development of Domain-Specific Solutions within the Polish Infrastructure for Advanced Scientific Research
PublikacjaThe Polish Grid computing infrastructure was established during the PL-Grid project (2009-2012). The main purpose of this Project was to provide the Polish scientists with an IT basic platform, allowing them to conduct interdisciplinary research on a national scale, and giving them transparent access to international grid resources via international grid infrastructures. Currently, the infrastructure is maintained and extended...
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Standards on Cyber Security Assessment of Smart Grid
PublikacjaSecurity evaluation of communication systems in smart grid poses a great challenge to the developers and operators. In recent years many new smart grid standards were proposed, which paradoxically results in the difficulty in finding a relevant publication in this plethora of literature. This paper presents the results of a systematic analysis which aimed at addressing this issue by identifying standards that present sound security...
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A Point Set Connection Problem for Autonomous Mobile Robots in a Grid
PublikacjaConsider an orthogonal grid of streets and avenues in a Manhattan-like city populated by stationary sensor modules at some intersections and mobile robots that can serve as relays of information that the modules exchange, where both module-module and module-robot communication is limited to a straight line of sight within the grid. The robots are oblivious and move asynchronously. We present a distributed algorithm that, given...
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Genetic Programming with Negative Selection for Volunteer Computing System Optimization
PublikacjaVolunteer computing systems like BOINC or Comcute are strongly supported by a great number of volunteers who contribute resources of their computers via the Web. So, the high efficiency of such grid system is required, and that is why we have formulated a multi-criterion optimization problem for a volunteer grid system design. In that dilemma, both the cost of the host system and workload of a bottleneck host are minimized. On...
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Reactive Energy Billing in Operator Tariffs in Poland
PublikacjaThe paper describes the current method of reactive energy billing in the tariffs of distribution grid operators in Poland. The current solutions are subject to critical assessment. Issues related to the motivation effect of the current solutions on consumers are analysed. Problems that occur in relation with connecting distributed generators to the distribution grid and challenges related to prosumer billing are indicated.
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Akustyka
PublikacjaW artykule przedstawiono zadania realizowane w ramach projektu PL GRID Plus przez zespół wykonawców Katedry Systemów Multimedialnych. Zadanie te obejmują przygotowanie zestawu usług umożliwiających wykonywanie obliczeń map hałasu i wpływu hałasu na słuch z wykorzystaniem infrastruktury PL GRID.
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Evaluation of Open Source SIEM for Situation Awareness Platform in the Smart Grid Environment
PublikacjaThe smart grid as a large-scale system of systems has an exceptionally large surface exposed to cyber-attacks, including highly evolved and sophisticated threats such as Advanced Persistent Threats (APT) or Botnets. When addressing this situation the usual cyber security technologies are prerequisite, but not sufficient. The smart grid requires developing and deploying an extensive ICT infrastructure that supports significantly...
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Cybersecurity and Privacy in Standards for Smart Grids – a Comprehensive Survey
PublikacjaResilient information and communications technologies are a prerequisite for reliable operation of smart grid. In recent years, many standards for the new form of electricity network have been proposed, which results in operators and other smart grid stakeholders having difficulties in finding the documents which can be related to their particular problems. The purpose of this paper is to bring in all smart grid standards that...
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Modified sliding mode control for seamless integration of P.V. energy in A.C. grid
PublikacjaSolar energy is a potentially abundant and reliable source of renewable energy. While it can undoubtedly increase grid reliability and efficiency, the inverted voltage generated from PV. sources may introduce distortion into the AC. grid. The proposed control mechanism, modified sliding mode control (MSMC), can seamlessly integrate the inverter output generated by obtaining DC. voltage from the boost converter linked with the PV....
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Balancing energy consumption in limited power grid with active front-end and three phase dual active bridge system
PublikacjaPaper deals with simulation analysis of bidirectional power converters system for charging station of electric vehicle in condition of limited power source in city infrastructure. In case of incapability to provide additional power supply through the grid by virtue of historical, architectural and economic reasons it is possible to solve this issue by implementation of mobile battery-powered supply source. The proposed bidirectional...
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Multi-agent graph searching and exploration algorithms
PublikacjaA team of mobile entities, which we refer to as agents or searchers interchangeably, starting from homebases needs to complete a given task in a graph.The goal is to build a strategy, which allows agents to accomplish their task. We analyze strategies for their effectiveness (e.g., the number of used agents, the total number of performed moves by the agents or the completion time).Currently, the fields of on-line (i.e., agents...
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Frequently updated noise threat maps created with use of supercomputing grid
PublikacjaAn innovative supercomputing grid services devoted to noise threat evaluation were presented. The services described in this paper concern two issues, first is related to the noise mapping, while the second one focuses on assessment of the noise dose and its influence on the human hearing system. The discussed services were developed within the PL-Grid Plus Infrastructure which accumulates Polish academic supercomputer centers....
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An Overview of Bidirectional EV Chargers: Empowering Traction Grid-Powered Chargers
PublikacjaIn recent years, the number of electric vehicles has been at least doubling year after year. As a result, today electric vehicles already account for approximately 10% of the global automotive market, which positively affects environment in urbanized areas. However, to take full advantage of the EV integration it is necessary to use renewable sources for their charging; optimally place charging stations/terminals; optimally manage...
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A Paradigm for HV, MV, LV Distribution Grid Development Planning
PublikacjaIn the literature, including that relating to businesses in the energy (and power) sector, the concept of these organizations’ operating paradigm may be found. The paper discusses the concept of the paradigm, with a focus on the power grid development planning paradigm. Against this background, issues related to energy security and power systems development trends and problems are presented. A new paradigm is proposed for distribution...
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Efektywne zrównoleglanie obliczeń w systemie klasy grid na przykładzie hipotezy Collatza
PublikacjaZaprezentowano problem Collatza oraz sposób jego adaptacji, pozwalający na realizację obliczeń w systemie typu grid. Zidentyfikowano również pożądane cechy problemów obliczeniowych, dzięki którym mogą one zostać zrównoleglone w sposób efektywny w systemach typu grid i porównano je z cechami zadań realizowanych typowo przy użyciu klastrów obliczeniowych.
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Application of PL-Grid Platform for Modeling of the Selected Acoustic Phenomena
PublikacjaDomain grids are specific computational environments, developed within the PLGrid Plus project. For the Acoustic domain grid two supercomputer grid based services were prepared. Dedicated software consists of the outdoor sound propagation module and psychoacoustical noise dosimeter. The results are presented in a form of maps of sound level and Temporary Threshold Shift (TTS) values, therefore the services may play an informative...
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The Application Of A Noise Mapping Tool Deployed In Grid Infrastructure For Creating Noise Maps Of Urban Areas
PublikacjaThe concept and implementation of the system for creating dynamic noise maps in PL-Grid infrastructure are presented. The methodology of dynamic acoustical maps creating is introduced. The concept of noise mapping, based on noise source and propagation models, was developed and employed in the system. The details of incorporation of the system to the PL-Grid infrastructure are presented. The results of simulations performed by...
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Scrutiny of power grids by penetrating PV energy in wind farms: a case study of the wind corridor of Jhampir, Pakistan
PublikacjaThis study examines the problems caused by intermittent renewable energy sources, especially wind farms, and suggests a different solar energy penetration strategy to improve their loading capacity. The study uses real-time data from a wind farm in Jhampir, Pakistan, to analyse and assess various aspects of grid stations connected to wind farms. Electrical Transient Analyzer Program is used to validate the results by linking...
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Solving Boundary Value Problems for Second Order Singularly Perturbed Delay Differential Equations by ε-Approximate Fixed-Point Method
PublikacjaIn this paper, the boundary value problem for second order singularly perturbed delay differential equation is reduced to a fixed-point problem v = Av with a properly chosen (generally nonlinear) operator A. The unknown fixed-point v is approximated by cubic spline vh defined by its values vi = vh(ti) at grid points ti, i = 0, 1, ... ,N. The necessary for construction the cubic spline and missing the first derivatives at the boundary...
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Power control system structure of doubly‐fed induction generator connected to current source converter
PublikacjaThe power control system structures for a doubly-fed generator (DFIG) are proposed. The classical field oriented control and the feedback control with the multi-scalar variables were considered. The generator is working in the AC grid connection mode. The rotor side of the generator is connected to the current source converter (CSC); the stator is directly related to the AC grid. The static feedback linearization using the multi-scalar...
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Estimation of the Maximum Permissible PV Power to be Connected to the MV Grid
PublikacjaIn recent decades, a significant increase in the share of renewable energy sources in power grids at various voltage levels has been observed. A number of articles have been published highlighting emerging problems in low-voltage grids with a large share of prosumers and in medium- and high-voltage grids to which photovoltaic (PV) plants are connected. The article analyzes the medium-voltage grid in terms of the possibility of...
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Scrutiny of power grids by penetrating PV energy in wind farms: a case study of the wind corridor of Jhampir, Pakistan
PublikacjaThis study examines the problems caused by intermittent renewable energy sources, especially wind farms, and suggests a different solar energy penetration strategy to improve their loading capacity. The study uses real-time data from a wind farm in Jhampir, Pakistan, to analyse and assess various aspects of grid stations connected to wind farms. Electrical Transient Analyzer Program is used to validate the results by linking these...
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Single-phase power electronics transformer with active functions for smart grid
PublikacjaThis paper presents the control of one cell of a modular single-phase power electronics transformer with active functions for meeting the smart grid concept. In this way, the converter could be used not only as a conventional transformer but also for grid such as reactive power, harmonic elimination and energy storage. The topology of the cell is composed by a bidirectional converter with three stages: a half bridge in the input...
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SMART GRID TECHNOLOGIES IN ELECTRIC POWER SUPPLY SYSTEMS OF PUBLIC TRANSPORT
PublikacjaNowadays the issue of electric energy saving in public transport is becoming a key area of interest which is connected both with a growth in environmental awareness of the society and an increase in the prices of fuel and electricity. It can be achieved by improving the usage of regenerative breaking. In 2016 the Przedsiębiorstwo Komunikacji Trolejbusowej (PKT, Trolleybus Transport Company) in Gdynia began practical implementation...