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Search results for: QUADRATIC STOCHASTIC OPERATORS
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Measurements of Dispersed Phase Velocity in Two-Phase Flows in Pipelines Using Gamma-Absorption Technique and Phase of the Cross-Spectral Density Function
PublicationThis paper concerns the application of the gamma radiation absorption method in the measurements of dispersed phase velocity in two-phase flows: liquid–gas flow in a horizontal pipe- line and liquid–solid particles in a vertical pipe. Radiometric sets containing two linear 241Am gamma radiation sources and two NaI(Tl) scintillation detectors were used in the research. Due to the stochastic nature of the signals obtained from the...
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Nonlinear generation of non-acoustic modes by low-frequency sound in a vibrationally relaxing gas
PublicationTwo dynamic equations referring to a weakly nonlinear and weakly dispersive flow of a gas in which molecular vibrational relaxation takes place. are derived. The first one governs an excess temperature associated with the thermal mode, and the second one describes variations in vibrational energy. Both quantities refer to non-wave types of gas motion. These variations are caused by the nonlinear transfer of acoustic energy into...
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The computational complexity of the backbone coloring problem for planar graphs with connected backbones
PublicationIn the paper we study the computational complexity of the backbone coloring problem for planar graphs with connected backbones. For every possible value of integer parameters λ≥2 and k≥1 we show that the following problem: Instance: A simple planar graph GG, its connected spanning subgraph (backbone) HH. Question: Is there a λ-backbone coloring c of G with backbone H such that maxc(V(G))≤k? is either NP-complete or polynomially...
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On simplification of residue scaling process in pipelined Radix-4 MQRNS FFT processor
PublicationResidue scaling is needed in pipelined FFT radix-4 processors based on the Modified Quadratic Residue Number System (MQRNS) at the output of each butterfly. Such processor uses serial connection of radix-4 butterflies. Each butterfly comprises n subunits, one for each modulus of the RNS base and generates four complex residue numbers. In order to prevent arithmetic overflow intermediate results after each butterfly have to be...
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On configuration of residue scaling process in pipelined radix-4 MQRNS FFT processor
PublicationResidue scaling is needed in pipelined FFT radix-4 processors based on the Modified Quadratic Residue Number System (MQRNS) at the output of each butterfly. Such processor uses serial connection of radix-4 butterflies. Each butterfly comprises n subunits, one for each modulus of the RNS base and outputs four complex residue numbers. In order to prevent the arithmetic overflow in the succesive stage, every number has to be scaled,...
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An Automatic Self-Tuning Control System Design for an Inverted Pendulum
PublicationA control problem of an inverted pendulum in the presence of parametric uncertainty has been investigated in this paper. In particular, synthesis and implementation of an automatic self-tuning regulator for a real inverted pendulum have been given. The main cores of the control system are a swing-up control method and a stabilisation regulator. The first one is based on the energy of an inverted pendulum, whereas the second one...
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Buckling and shape control of prestressable trusses using optimum number of actuators
PublicationThis paper describes a method to control the nodal displacement of prestressable truss structures within the desired domains. At the same time, the stress in all members is unleashed to take any value between the allowable tensile stress and critical buckling stress. The shape and stresses are controlled by actuating the most active members. The technique considers the members’ initial crookedness, residual stresses, and slenderness...
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A decision-making system supporting selection of commanded outputs for a ship's propulsion system with a controllable pitch propeller
PublicationThe ship's operators have to make decisions regarding the values of commanded outputs (commanded engine speed and pitch ratio) which ensure maximum vessel speed and minimum fuel consumption. Obviously, the presented decision problems are opposed. Therefore, there is a need for a compromise solution that enables more flexible vessel voyage planning. This paper deals with development of a computer-aided system supporting selection...
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The Dynamic Model of Magnetic Hysteresis
PublicationThis paper presents the scalar dynamic magnetic hysteresis model based on the Preisach theory. The important role in this theory played hysteresis operator states. The changes of these operators` states are not immediate in the dynamic model but they are a function of time and parameter k representing the magnetic properties of the material. In this paper the transient state of the hysteresis operator is defined by the nonlinear...
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Inlet air fogging of marine gas turbine in power output loss compensation
PublicationThe use of inlet air fogging installation to boost the power for gas turbine engines is widely applied in the power generation sector. The application of fogging to mechanical drive is rarely considered in the literature [1]. This paper will cover some considerations relating to its application to gas turbines in ship drive. There is an important evaporative cooling potential throughout the world when the dynamic data is evaluated,...
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Living and working beneath the sea – next approach
PublicationThe idea of living beneath the sea is very new if compared with millennia of shipping activity. In fact, ocean surface was considered mainly as medium suitable for transport of persons and goods as well as aggression and robbery. More practical attempts to live “on” the water surface are limited to well protected internal waters. The presented concept of “an underwater-above water accommodation, especially for residential purposes”...
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Fractional Order Dynamic Positioning Controller
PublicationImproving the performance of Dynamic Positioning System in such applications as station keeping, position mooring and slow speed references tracking requires improving the position and heading control precision. These goals can be achieved through the improvement of the ship control system. Fractional-order calculus is a very useful tool which extends classical, integer-order calculus and is used in contemporary modeling and control...
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Zastosowanie audytu wewnętrznego u operatorów produkcyjnych w zapobieganiu kryzysom-studium przypadku
PublicationGłównym tematem artykułu była analiza badań przeprowadzonych u producenta farb proszkowych przedsiębiorstwa X, w zakresie zastosowania audytu wewnętrznego, jako metody pozwalającej na zapobieganie pojawienia się kryzysu. Właściwa współpraca operatorów produkcyjnych z menedżerami ma kluczowe zna-czenie dla budowy właściwej pozycji audytu wewnętrznego w przedsiębiorstwie X. Brak należytej współpracy na etapie badań, przy braku...
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Multiresolution analysis and adaptive estimation on a sphere using stereographic wavelets
PublicationWe construct an adaptive estimator of a density function on d dimensional unit sphere Sd (d ≥ 2), using a new type of spherical frames. The frames, or as we call them, stereografic wavelets are obtained by transforming a wavelet system, namely Daubechies, using some stereographic operators. We prove that our estimator achieves an optimal rate of convergence on some Besov type class of functions by adapting to unknown smoothness....
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Applications of Tensor Analysis in Continuum Mechanics
PublicationA tensor field is a tensor-valued function of position in space. The use of tensor fields allows us to present physical laws in a clear, compact form. A byproduct is a set of simple and clear rules for the representation of vector differential operators such as gradient, divergence, and Laplacian in curvilinear coordinate systems. The tensorial nature of a quantity permits us to formulate transformation rules for its components...
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Carbon Dioxide and Water Vapour Fluxes of a Alkaline Fen and Their Dependence on Reflectance
PublicationThis study shows results of parallel measurements of greenhouse gases fluxes (carbon dioxide and water vapour) and canopy reflectance of alkaline fen. Fluxes were measured using eddy-covariance technique on micrometeorological station located in the Upper Biebrza Basin (NE Poland) in Rogożynek Village. Study site is located in the Biebrza National Park which was established to protect one of the biggest coherent lowland wetland...
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Measurement of Impulse Response of Shallow Water Communication Channel by Correlation Method
PublicationPerformances of underwater acoustic communication (UAC) systems are strongly related to specific propagation conditions of the underwater channel; conditions that can additionally change in time due to the movement of the acoustic system transmitter and receiver or to reflection by underwater objects of the transmitted signal. The time-varying impulse response is a comprehensive description of dynamically changing transmission...
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Theoretical Model of Acoustic Wave Propagation in Shallow Water
PublicationThe work is devoted to the propagation of low frequency waves in a shallow sea. As a source of acoustic waves, underwater disturbances generated by ships were adopted. A specific feature of the propagation of acoustic waves in shallow water is the proximity of boundaries of the limiting media characterised by different impedance properties, which affects the acoustic field coming from a source situated in the water layer “ deformed”...
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Effects of subfilter velocity modelling on dispersed phase in LES of heated channel flow
PublicationA non-isothermal turbulent flow with the dispersed phase is modelled using the Large Eddy Simulation (LES) approach for fluid, one-way coupled with the equations of point-particle evolution. The channel is heated at both walls and isoflux boundary conditions are applied for fluid. Particle velocity and thermal statistics are computed. Of particular interest are the r.m.s. profiles and the probability density function of particle...
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Application Isssues of the Semi-Markov Reliability Model
PublicationPredicting the reliability of marine internal combustion engines, for instance, is of particular importance, as it makes it possible to predict their future reliability states based on the information on the past states. Correct reliability prediction is a complex process which consists in processing empirical results obtained from operating practice, complemented by analytical considerations. The process of technical state changes...
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Towards Improving Optimised Ship Weather Routing
PublicationThe aim of the paper is to outline a project focusing on the development of a new type of ship weather routing solution with improved uncertainty handling, through better estimation of ship performance and responses to sea conditions. Ensemble forecasting is considered to take into account the uncertainty levels that are typical of operations in a stochastic environment. Increased accuracy of weather prediction is achieved through...
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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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Potential Application of Solar Energy Systems for Electrified Urban Transportation Systems
PublicationThe paper presents a novel approach toward the use of solar energy systems in public transportation. The concept of energy generation in PV systems for supplying a trolleybus transportation system is proposed for the city of Gdynia (Poland). The suggested way of energy production allows reducing the environmental harm impact of the municipal transportation system. Moreover, the proposed way of green energy use can be a more profitable...
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Inseparability criteria based on matrices of moments
PublicationInseparability criteria for continuous and discrete bipartite quantum states based on moments of annihilationand creation operators are studied by developing the idea of Shchukin-Vogel criterion Phys. Rev. Lett. 95,230502 2005. If a state is separable, then the corresponding matrix of moments is separable too. Thus, wederive generalized criteria based on the separability properties of the matrix of moments. In particular, acriterion...
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Comparison of reproduction strategies in genetic algorithm approach to graph searching
Publicationgenetic algorithms (ga) are a well-known tool used to obtain approximate solutions to optimization problems. successful application of genetic algorithm in solving given problem is largely dependant on selecting appropriate genetic operators. selection, mutation and crossover techniques play a fundamental role in both time needed to obtain results and their accuracy. in this paper we focus on applying genetic algorithms in calculating...
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Influence of Self-Similar Traffic Type on Performance of QoS Routing Algorithms
PublicationProviding a Quality of Services (QoS) into current telecommunication networks based on packet technology is a big challenge nowadays. Network operators have to support a number of new services like voice or video which generate new type of traffic. This traffic serviced with QoS in consequence requires access to appropriate network resources. Additionally, new traffic type is mixed with older one, like best-effort. Analysis of...
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HIGH LEVEL SYNTHESIS IN FPGA OF TCS/RNS CONVERTER
PublicationThe work presents the design process of the TCS/RNS (two's complement–to– residue) converter in Xilinx FPGA with the use of HLS approach. This new approach allows for the design of dedicated FPGA circuits using high level languages such as C++ language. Such approach replaces, to some extent, much more tedious design with VHDL or Verilog and facilitates the design process. The algorithm realized by the given hardware circuit is...
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Robustness of quantum-randomness expansion protocols in the presence of noise
PublicationIn this paper we investigate properties of several randomness generation protocols in the device independent framework. Using Bell-type inequalities it is possible to certify that the numbers generated by an untrusted device are indeed random. We present a selection of certificates which guarantee two bits of randomness for each run of the experiment in the noiseless case and require the parties to share a maximally entangled state....
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Evolutionary approach to ship's trajectory planning within Traffic Separation Schemes
PublicationThe paper presents the continuation of the author's research on evolutionary approach to ship trajectory planning. While the general problem of the evolutionary trajectory planning has already been solved, no one has yet touched one of its specific aspects: evolutionary trajectory planning within Traffic Separation Schemes. Traffic Separation Scheme (TSS) is a traffic-management route-system complying with rules of the International...
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Evolutionary Sets Of Safe Ship Trajectories: A New Approach To Collision Avoidance
PublicationThe paper introduces a new method of solving multi-ship encounter situations for both open waters and restricted water regions. The method, called evolutionary sets of safe trajectories combines some of the assumptions of game theory with evolutionary programming and aims to find optimal set of safe trajectories of all ships involved in an encounter situation. In a two-ship encounter situation it enables the operator of an on-board...
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Scalar and Vector acoustic fields and sources: a new look
PublicationA study of fundamental problems of the wavefields that are the reaction of fluid continuum on two kinds of primary actions in fluid, then on two kinds of elementary point sources, is presented in this paper, based on the assumption of the physical duality of linear fluid mechanics and the formal symmetry of mathematical description. The two fundamental wavefields generated in fluid by physical point sources are discussed in detail,...
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Knowledge-based functional safety and security management in hazardous industrial plants with emphasis on human factors
PublicationExisting and emerging new hazards have significant potential to impact destructively operation of technical systems, hazardous plants, and systems / networks of critical infrastructure. The programmable control and protection systems play nowadays an important role in reducing and controlling risk in the process of hazardous plant operation. It is outlined how to deal with security related hazards concerning such systems to be...
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Parseval Wavelet Frames on Riemannian Manifold
PublicationWe construct Parseval wavelet frames in L 2 (M) for a general Riemannian manifold M and we show the existence of wavelet unconditional frames in L p (M) for 1 < p < ∞. This is made possible thanks to smooth orthogonal projection decomposition of the identity operator on L 2 (M), which was recently proven by Bownik et al. (Potential Anal 54:41–94, 2021). We also show a characterization of Triebel–Lizorkin F sp,q (M) and Besov B...
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Analysis of Factors Influencing the Prices of Tourist Offers
PublicationTourism is a significant branch of many world economies. Many factors influence the volume of tourist traffic and the prices of trips. There are factors that clearly affect tourism, such as COVID-19. The paper describes the methods of machine learning and process mining that allow for assessing the impact of various factors (micro, mezzo and macro) on the prices of tourist offers. The methods were used on large sets of real data...
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Entangled Histories vs. the Two-State-Vector Formalism - Towards a Better Understanding of Quantum Temporal Correlations
PublicationThe Two-State-Vector formalism and the Entangled Histories formalism are attempts to betterunderstand quantum correlations in time. Both formalisms share some similarities, but they are notidentical, having subtle differences in their interpretation and manipulation of quantum temporalstructures. However, the main objective of this paper is to prove that, with appropriately definedscalar products, both formalisms can be...
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Latest Insights on Novel Deep Eutectic Solvents (DES) for Sustainable Extraction of Phenolic Compounds from Natural Sources
PublicationPhenolic compounds have long been of great importance in the pharmaceutical, food, and cosmetic industries. Unfortunately, conventional extraction procedures have a high cost and are time consuming, and the solvents used can represent a safety risk for operators, consumers, and the environment. Deep eutectic solvents (DESs) are green alternatives for extraction processes, given their low or non-toxicity, biodegradability, and reusability....
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Optimizing of target detection and tracking processes realized on consoles of passive sonar with linear towed antenna
PublicationThe long-range passive towed sonar was first modernised a few years ago. Building on operator experience over that period, a concept was developed of optimising the tasks performed by sonar operators, and improving forms of imaging to inform about object detection and support object tracking. The concept was implemented and successfully tested during ships’ manoeuvres. The optimisation of operator tasks was designed to keep listening...
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PROBABILISTYCZNE ASPEKTY ZUŻYCIA SKOJARZEŃ CIERNYCH UKŁADÓW KORBOWO-TŁOKOWYCH NA PRZYKŁADZIE OKRĘTOWYCH SILNIKÓW SPALINOWYCH DWUSUWOWYCH NAPĘDU GŁÓWNEGO
PublicationW artykule przestawiono propozycję rozpatrywania zarówno obciążenia jak i zużywania ślizgowych skojarzeń ciernych (łożysk głównych i korbowych) układów korbowo-tłokowych silników spalinowych, zwłaszcza głównych, a także skojarzeń „tłok-tuleja” tych silników, jako procesów stochastycznych. Propozycję tę uzasadniono tym, że deterministyczne podejście do badania zarówno obciążenia jak i zużycia wspomnianych skojarzeń uniemożliwia...
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Deformation mitigation and twisting moment control in space frames
PublicationOver the last five decades, space frames have centered on the modernization of touristic zones in view of architectural attractions. Although attempts to control joint movement and minimize axial force and bending moment in such structures were made sufficiently, twisting moments in space frames have been underestimated so far. In space frames, external load or restoring the misshapen shape may cause twisting in members. We herein...
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The Backbone Coloring Problem for Bipartite Backbones
PublicationLet G be a simple graph, H be its spanning subgraph and λ≥2 be an integer. By a λ -backbone coloring of G with backbone H we mean any function c that assigns positive integers to vertices of G in such a way that |c(u)−c(v)|≥1 for each edge uv∈E(G) and |c(u)−c(v)|≥λ for each edge uv∈E(H) . The λ -backbone chromatic number BBCλ(G,H) is the smallest integer k such that there exists a λ -backbone coloring c of G with backbone H satisfying...
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Catheter-induced coronary artery and aortic dissections. A study of the mechanisms, risk factors, and propagation causes
PublicationBackground: Only the incidence, management, and prognosis of catheter-induced coronary artery and aortic dissections have been systematically studied until now. We sought to evaluate their mechanisms, risk factors, and propagation causes. Methods: Electronic databases containing 76,104 procedures and complication registries from 2000– –2020 were searched and relevant cineangiographic studies adjudicated. Results: Ninety-six dissections...
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On existence and uniqueness of weak solutions for linear pantographic beam lattices models
PublicationIn this paper, we discuss well-posedness of the boundary-value problems arising in some “gradientincomplete” strain-gradient elasticity models, which appear in the study of homogenized models for a large class ofmetamaterials whosemicrostructures can be regarded as beam lattices constrained with internal pivots. We use the attribute “gradient-incomplete” strain-gradient elasticity for a model in which the considered strain energy...
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Assessing the Effects of the Road Surface and Weather Conditions on Road Safety
PublicationWhen transport is analysed for its safe delivery the focus is mainly on assessing the safety of roads and the risk of undesired events. These include road accidents, an occurrence which is relatively rare and random. Randomness means that accidents depend on several factors which are partly deterministic (can be controlled) and partly stochastic (random and unpredictable). The set of crash contributing factors can be classified...
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A CONCEPT OF DETERMINING THE RELATION BETWEEN LOAD AND WEAR OF TRIBOLOGICAL SYSTEMS OF SHIP MAIN SELF-IGNITION ENGINES BY USING PROBABILISTIC APPROACH PROBABILISTIC APPROACH
PublicationThis paper presents a proposal of simultaneous consideration of load and wear associated with it , of tribological systems of ship main engines (intended for ship propulsion) . Based on results of investigations it was assumed that both the load Q (i.e. a cause of wear ) and the wear Z (i.e. an effect of load occurrence) considered in a given time t(0 ≤ t ≤ t) are random variables Qt and Zt, respectively. There was characterized...
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Method of managing drill cuttings from shale gas formations
PublicationProposed management method of drill cuttings involves recycling for the expanded clay production. A theoretical presentation of the possibility, choosing planning path based on similarity between the materials used in the manufacture of expanded clay and oily cuttings. Application for the main stages of manufacture of expanded clay production of drill cuttings from shale gas extraction. Introduced into circulation solid waste partly...
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Power Electronics Building Blocks for implementing Smart MV/LV Distribution Transformers for Smart Grid
PublicationWith an observed increase in the involvement of active consumers in activities aimed at improving energy efficiency and increasing interest in producing energy from renewable sources, there is a need for the development of new technologies enabling the distribution network operators to offer new services and functionalities. Smart MV/LV distribution transformers are characterized by a compact three-stage design, including an...
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COLREGS compliance in Evolutionary Sets of Cooperating Ship Trajectories
PublicationIn general, Evolutionary Sets of Cooperating Ship Trajectories combine some of the assumptions of game theory with evolutionary programming and aim to find optimal set of cooperating trajectoriesof all ships involved in an encounter situation. In a two-ship encounter situation the method enables the operator of an on-board collision-avoidance system to predict the most probable behaviour of atarget and to plan the own manoeuvres...
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Advancing Solar Energy: Machine Learning Approaches for Predicting Photovoltaic Power Output
PublicationThis research is primarily concentrated on predicting the output of photovoitaic power, an essential field in the study of renewable energy. The paper comprehensively reviews various forecasting methodologies, transitioning from conventional physical and statistical methods to advanced machine learning (ML) techniques. A significant shift has been observed from traditional point forecasting to machine learning-based forecasting...
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Planning a Cost-Effective Delay-Constrained Passive Optical Network for 5G Fronthaul
PublicationWith the rapid growth in the telecommunications industry moving towards 5G and beyond (5GB) and the emergence of data-hungry and time-sensitive applications, Mobile Network Operators (MNOs) are faced with a considerable challenge to keep up with these new demands. Cloud radio access network (CRAN) has emerged as a cost-effective architecture that improves 5GB performance. The fronthaul segment of the CRAN necessitates a high-capacity...
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Neural modelling of dynamic systems with time delays based on an adjusted NEAT algorithm
PublicationA problem related to the development of an algorithm designed to find an architecture of artificial neural network used for black-box modelling of dynamic systems with time delays has been addressed in this paper. The proposed algorithm is based on a well-known NeuroEvolution of Augmenting Topologies (NEAT) algorithm. The NEAT algorithm has been adjusted by allowing additional connections within an artificial neural network and...