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Wyniki wyszukiwania dla: COMPUTATIONAL EFFICIENCY

Considerations of Computational Efficiency in Volunteer and Cluster Computing
PublikacjaIn the paper we focus on analysis of performance and power consumption statistics for two modern environments used for computing – volunteer and cluster based systems. The former integrate computational power donated by volunteers from their own locations, often towards social oriented or targeted initiatives, be it of medical, mathematical or space nature. The latter is meant for high performance computing and is typically installed...

Modeling of Performance, Reliability and Energy Efficiency in LargeScale Computational Environments
PublikacjaLarge scale of complexity of distributed computational systems imposes special challenges for prediction of quality in such systems. Existing quality models for lowerscale systems include functionality, performance, reliability, flexibility and usability. Among these attributes, performance and reliability have a particular significance to the largescale systems computing quality modeling due to their strong dependence on the...

Modeling of Performance, Reliability and Energy Efficiency in LargeScale Computational Environment
PublikacjaLarge scale of complexity of distributed computational systems imposes special challanges for prediction of quality in such systems.Existing quality models for lowerscale systems include functionality,performance,reliability,flexibility and usability.Among these attributes,performance and reliability have a particular significance to the largescale systems computing quality modeling due to their strong dependence on the system...

ANALYSIS OF EFFECTIVENESS AND COMPUTATIONAL COMPLEXITY OF TREND REMOVAL METHODS
PublikacjaThe paper presents a method of processing measurement data due to remove slowly varying component of the trend occurring in the recorded waveforms. Comparison of computational complexity and trend removal efficiency between some commonly used methods is presented. The impact of these procedures on probability distribution and power spectral density is shown. Effectiveness and computational complexity of these methods depend essentially...

Reduction of Computational Complexity in Simulations of the Flow Process in Transmission Pipelines
PublikacjaThe paper addresses the problem of computational efficiency of the pipeflow model used in leak detection and identification systems. Analysis of the model brings attention to its specific structure, where all matrices are sparse. With certain rearrangements, the model can be reduced to a set of equations with tridiagonal matrices. Such equations can be solved using the Thomas algorithm. This method provides almost the same values...

Computationally Effcient Solution of a 2D Diffusive Wave Equation Used for Flood Inundation Problems
PublikacjaThis paper presents a study dealing with increasing the computational efficiency in modeling floodplain inundation using a twodimensional diffusive wave equation. To this end, the domain decomposition technique was used. The resulting onedimensional diffusion equations were approximated in space with the modified finite element scheme, whereas time integration was carried out using the implicit twolevel scheme. The proposed...

Design and computational fluid dynamics analysis of the last stage of innovative gassteam turbine
PublikacjaResearch regarding blade design and analysis of flow has been attracting interest for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics and computational flow mechanics. Currently a combination of mentioned methods is used for the design of turbine blades. These methods enabled us to improve flow efficiency...

The efficiency of turbomachinery in the zeroand threedimensional approaches
PublikacjaEfficiency of turbomachinery is usually defined using an isentropic process. This approach provides a reliable reference point only when pressure and temperature measurements are available, e.g. at the casing inlet and outlet. In the case of a single stage internal efficiency determination the reference point is difficult. Computational fluid dynamics allows for an exact calculation of values of losses occurring in a turbine...

On the Structure of Time in Computational Semantics of a VariableStep Solver for Hybrid Behavior Analysis
PublikacjaHybrid 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...

Effect of chemical structure on complexation efficiency of aromatic drugs with cyclodextrins: The example of dibenzazepine derivatives
PublikacjaIt is widely believed that the hydrophobic effect governs the binding of guest molecules to cyclodextrins (CDs). However, it is also known that high hydrophobicity of guest molecules does not always translate to the formation of stable inclusion complexes with CDs. Indeed, a plethora of other factors can play a role in the efficiency of guest–CD interactions, rendering structurebased prediction of the complexation efficiency with...

Experimental and Computational Fluid Dynamics Studies on Straight and UBend Double Tube Heat Exchangers with Active and Passive Enhancement Methods
PublikacjaIn this work, the authors wanted to demonstrate the possibility to increase the heat transfer efficiency by using simple wire coil inserts to create turbulent flow in the boundary layer as well as air blowing into the annulus of the pipe. Experimental investigations were carried out for four heat exchanger constructions, i.e., plain double tube, turbulized double tube, plain Ubend double tube, Utube with turbulator, plain double...

Diaryl Sulfide Derivatives as Potential Iron Corrosion Inhibitors: A Computational Study
PublikacjaThe present work aimed to assess six diaryl sulfide derivatives as potential corrosion inhibitors. These derivatives were compared with dapsone (4,4′diaminodiphenyl sulfone), a common leprosy antibiotic that has been shown to resist the corrosion of mild steel in acidic media with a corrosion efficiency exceeding 90%. Since all the studied compounds possess a common molecular backbone (diphenyl sulfide), dapsone was taken as the...

Increase of power and efficiency of the 900 MW supercritical power plant through incorporation of the ORC
PublikacjaThe objective of the paper is to analyse thermodynamical and operational parameters of the supercritical power plant with reference conditions as well as following the introduction of the hybrid system incorporating ORC. In ORC the upper heat source is a stream of hot water from the system of heat recovery having temperature of 90 °C, which is additionally aided by heat from the bleeds of the steam turbine. Thermodynamical analysis...

Computational methods for calculation of binding free energy for ligandreceptor complexes
PublikacjaAccurate description of the molecular complexes energetic influence is required for understanding of many biological functions carried out by proteins. Therefore, estimation of binding free energy for ligandreceptor complexes is of highest importance for structurebased ligand design and drug discovery approaches.Experimental methods of determination of difference in Gibbs'es free energy have many limitations. Thus, computational...

Direct spectrum detection based on Bayesian approach
PublikacjaThe paper investigates the Bayesian framework's performance for a direct detection of spectrum parameters from the compressive measurements. The reconstruction signal stage is eliminated in by the Bayesian Compressive Sensing algorithm, which causes that the computational complexity and processing time are extremely reduced. The computational efficiency of the presented procedure is significantly...

On design and analysis of flow characteristics of the last stage of gassteam turbine
PublikacjaResearch regarding blade design and analysis of flow have been conducted for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics (CFD) and computational flow mechanics (CFM). Currently a combination of mentioned methods is used for design of turbine blades. These methods enabled us to improve flow efficiency...

Expedited Design Closure of Antenna Input Characteristics by Trust Region Gradient Search and Principal Component Analysis
PublikacjaOptimizationbased parameter tuning has become an inherent part of contemporary antenna design process. For the sake of reliability, it is typically conducted at the level of fullwave electromagnetic (EM) simulation models. This may incur considerable computational expenses depending on the cost of an individual EM analysis, the number of adjustable variables, the type of task (local, global, single/multiobjective optimization),...

Influence of nonlinearities on the efficiency and accuracy of FEM calculations on the example of a steel buildup thinwalled column
PublikacjaDue to the increase of computing capabilities of standard processing units, it is possible to perform complex analyses, considering a number of nonlinearities, such as geometric, material and boundary (contact) even on personal computers. In the paper, the authors have analysed the efficiency and accuracy of standard PC’s FEM calculations performed in Abaqus CAE 2017 software on the example of a critical load assessment of a thinwalled...

Complexity analysis of the Pawlak’s flowgraph extension for reidentification in multicamera surveillance system
PublikacjaThe idea of Pawlak’s flowgraph turned out to be a useful and convenient container for a knowledge of objects’ behaviour and movements within the area observed with a multicamera surveillance system. Utilization of the flowgraph for modelling behaviour admittedly requires certain extensions and enhancements, but it allows for combining many rules into a one data structure and for obtaining parameters describing how objects tend...

CFD analysis of fluid flow through the labyrinth seal
PublikacjaSteam and gas turbines are some of the fundamental means of power generation. The energy efficiency of the turbines, however, is not satisfactory. Ever since the startup of the first turbine in the world, engineers have been striving for their increased efficiency. Multiple solutions to the problem of steam loss in an operating turbine are available. The use of seals is one of them. Empirical methods or numerical calculations...

An Efficient Framework For Fast Computer Aided Design of Microwave Circuits Based on the HigherOrder 3D FiniteElement Method
PublikacjaIn this paper, an efficient computational framework for the fullwave design by optimization of complex microwave passive devices, such as antennas, filters, and multiplexers, is described. The framework consists of a computational engine, a 3D object modeler, and a graphical user interface. The computational engine, which is based on a finite element method with curvilinear higherorder tetrahedral elements, is coupled with builtin...

ResiduePole Methods for Variability Analysis of Sparameters of Microwave Devices with 3D FEM and Mesh Deformation
PublikacjaThis paper presents a new approach for variability analysis of microwave devices with a high dimension of uncertain parameters. The proposed technique is based on modeling an approximation of system by its poles and residues using several modeling methods, including ordinary kriging, Adaptive Polynomial Chaos (APCE), and Support Vector Machine Regression (SVM). The computational cost is compared with the traditional MonteCarlo...

Communication Model Order Reduction in Hybrid Methods Involving Generalized Impedance Matrix
PublikacjaA novel strategy for the efficient analysis of frequencydomain scattering electromagnetic problems in open and closed domains is presented. A fully automatic modelorder reduction technique, called the enhanced reducedbasis method, is applied to increase the efficiency of the hybrid approach, which combines the finiteelement and modematching methods. Numerical tests show that the proposed algorithm yields reliable and highly...

Application of advanced CFD simulations in seakeeping analysis of ships (case study)
PublikacjaThe novel design process of many types of ships needs estimation of seakeeping properties. Especially ships like Offshore Supply Vessels, Wind Farm Support Vessels, Research Vessels, ferries, military vessels, rescue vessels require extended analysis of ship behavior on rough sea. The main reason for improving ships operability in different sea conditions is need of rising efficiency of propulsion system, reducing hull added resistance,...

An Improvement of Global Complex Roots and Poles Finding Algorithm for Propagation and Radiation Problems
PublikacjaAn improvement of the recently developed global roots finding algorithm has been proposed. The modification allows to shorten the computational time by reducing the number of function calls. Moreover, both versions of the algorithms (standard and modified) have been tested for numerically defined functions obtained from spectral domain approach and field matching method. The tests have been performed for three simple microwave...

Exact modal absorbing boundary condition for waveguide simulations  discrete Green's function approach
PublikacjaA modal absorbing boundary condition (ABC) based on the discrete Green's function (DGF) is introduced and applied for termination of waveguides simulated by means of the finitedifference timedomain (FDTD) method. The differences between the developed approach and implementations already demonstrated in the literature are presented. By applying DGF, a consistent theoretical approach to modal ABC in the FDTD method is obtained....

Macromodeling techniques for accelerated finite element analysis
PublikacjaThis paper deals with the Model Order Reduction applied locally in the Finite Element Method (FEM) analysis. Due to the reduction process, blocks of FEM system matrices associated with selected subregions of the computational domain are projected onto the subspaces spanned by the vectors of suited orthogonal projection basis. In effect, large and sparse FEM matrices are replaced with small and dense ones, called macromodels. This...

FPGABased Implementation of Real Time Optical Flow Algorithm and Its Applications for Digital Image Stabilization
PublikacjaAn efficient simplification procedure of the optical flow (OF) algorithm as well as its hardware implementation using the field programmable gate array (FPGA) technology is presented. The modified algorithm is based on block matching of subsets of successive frames, and exploits onedimensional representation of subsets as well as the adaptive adjustments of their sizes. Also, an l1normbased correlation function requiring no...

MultiFidelity Local Surrogate Model for Computationally Efficient Microwave Component Design Optimization
PublikacjaIn order to minimize the number of evaluations of highfidelity (“fine”) model in the optimization process, to increase the optimization speed, and to improve optimal solution accuracy, a robust and computationalefficient multifidelity local surrogatemodel optimization method is proposed. Based on the principle of response surface approximation, the proposed method exploits the multifidelity coarse models and polynomial interpolation...

A technique of experiment aided virtual prototyping to obtain the best spindle speed during face milling of largesize structures
PublikacjaThe paper presents an original method concerning vibration suppression problem during milling of largesize and geometrically complicated workpieces with the use of novel way of selecting the spindle speed. This consists in repetitive simulations of the cutting process for subsequent values of the spindle speed, until the best vibration state of the workpiece is reached. An appropriate method of obtaining a computational model,...

Electromagnetic Simulation with 3D FEM for Design Automation in 5G Era
PublikacjaElectromagnetic simulation and electronic design automation (EDA) play an important role in the design of 5G antennas and radio chips. The simulation challenges include electromagnetic effects and long simulation time and this paper focuses on simulation software based on finiteelement method (FEM). The stateoftheart EDA software using novel computational techniques based on FEM can not only accelerate numerical analysis, but...

Facet effect of TiO2 nanostructures from TiOF2 and their photocatalytic activity
PublikacjaIn this study, special attention is focused on the design of TiO2 morphology and microstructure in the twostep preparation procedure using TiOF2 as a precursor to study their photodegradation mineralization efficiency. Firstly, TiOF2 was synthesized by a simple solvothermal method using titanium(IV) tetrafluoride, which was further used as a precursor in preparation of anatase 2D nanosheets, octahedral, decahedral, and rectangular prisms...

Global Complex Roots and Poles Finding Algorithm Based on Phase Analysis for Propagation and Radiation Problems
PublikacjaA flexible and effective algorithm for complex roots and poles finding is presented. A wide class of analytic functions can be analyzed, and any arbitrarily shaped search region can be considered. The method is very simple and intuitive. It is based on sampling a function at the nodes of a regular mesh, and on the analysis of the function phase. As a result, a set of candidate regions is created and then the roots/poles are verified...

Local mesh morphing technique for parametrized macromodels in the finite element method
PublikacjaThis paper presents a novel approach for enhancing the efficiency of the design process of microwave devices by means of the finite element method. It combines mesh morphing with local model order reduction (MOR) and yields parametrized macromodels that can be used to significantly reduce the number of variables in the FEM system of equations and acceleration of computer simulation. A projection basis for local reduction is generated...

Lowcost multiobjective optimization of antennas using Pareto front exploration and response features
PublikacjaIn the paper, a procedure for lowcost multiobjective optimization of antenna structures is presented. Our approach is based on exploration of the Pareto front representing the best possible tradeoffs between conflicting objectives, here, the structure size and its electrical performance. Starting from the design representing the best inband reflection level, subsequent Paretooptimal designs are identified through local constrained...

Quality Modeling in Grid and VolunteerComputing Systems
PublikacjaA model of computational quality in largescale 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...

Impact of dyes isomerization effect on the charge transfer phenomenon occurring on the dye/nanosemiconductor interface
PublikacjaThe present work aimed to find the answer how does the isomerization of the Ru based dyes affect the overall photontocurrent efficiency of the DSSCs and to explain the charge transfer phenomenon occurring on the dye/ nanosemiconductor interface. Therefore, electronic and optical properties of three bipyridine derivatives anchored on the TiO2 electrode were investigated by computational simulations based on quantum chemistry codes...

Fast geometry scaling of miniaturized microwave couplers with power split correction
PublikacjaRedesigning a microwave circuit for various operating conditions is a practically important yet challenging problem. The purpose of this article is development and presentation of a technique for fast geometry scaling of miniaturized microwave couplers with respect to operating frequency. Our approach exploits an inverse surrogate model constructed using several reference designs that are optimized for a set of operating frequencies...

Numerically efficient algorithm for compact microwave device optimization with flexible sensitivity updating scheme
PublikacjaAn efficient trustregion algorithm with flexible sensitivity updating management scheme for electromagnetic (EM)driven design optimization of compact microwave components is proposed. During the optimization process, updating of selected columns of the circuit response Jacobian is performed using a rankone Broyden formula (BF) replacing finite differentiation (FD). The FD update is omitted for directions sufficiently well aligned...

Fast EMdriven size reduction of antenna structures by means of adjoint sensitivities and trust regions
PublikacjaIn this letter, a simple yet robust and computationally efficient optimization technique for explicit size reduction of antenna structures is presented. Our approach directly handles the antenna size as the main design objective, while ensuring satisfactory electrical performance by means of suitably defined penalty functions. For the sake of accuracy, the antenna structure is evaluated using highfidelity EM simulation. In order...

Stirling engines  the state of technology development and computational models
PublikacjaStirling engines represent a technologically important solution in combined heat and power systems. Their use enables the achievement of over 90 percent efficiency in the management of the primary energy source with a very high durability of the device, mainly due to the lack of contact of the working gas with external factors and a very small number of mechanical components. The use of a Stirling engine may be equally important...

Comprehensive comparison of compact UWB antenna performance by means of multiobjective optimization
PublikacjaAn optimizationbased procedure for comprehensive performance comparison of alternative compact UWB antenna topologies is discussed. The assessment of the antenna performance is conducted with respect to the structure size and its reflection response. More specifically, the best possible tradeoffs between these two figures of merit are identified through multiobjective optimization at the level...

Multilevel model order reduction with generalized compression of boundaries for 3d FEM electromagnetic analysis
PublikacjaThis paper presents a multilevel Model Order Reduction technique for a 3D electromagnetic Finite Element Method analysis. The reduction process is carried out in a hierarchical way and involves several steps which are repeated at each level. This approach brings about versatility and allows one to efficiently analyze complex electromagnetic structures. In the proposed multilevel reduction the entire computational domain is covered...

Fast MultiObjective Antenna Optimization Using Sequential Patching and VariableFidelity EM Models
PublikacjaIn this work, a technique for fast multiobjective design optimization of antenna structures is presented. In our approach, the initial approximation of the Pareto set representing the best possible tradeoffs between conflicting design objectives is obtained by means of sequential patching of the design space. The latter is a stencilbased search that aims at creating a path that connects the extreme Paretooptimal designs (obtained...

Numerical modeling of exciton impact in two crystalographic phases of the organolead halide perovskite (CH3NH3PbI3) solar cell
PublikacjaTo improve the power conversion efficiency of solar cells based on organo–lead halide perovskites, a detailed understanding of the device physics is fundamental. Here, a computational analysis of excitons impact is reported for these types of photocell. Numerical calculations based on the model, which take into account electronic charge carriers (electrons and holes), excitons and ions, have been carried out. The role of excitons...

Optimization of the spindle speed during milling of largesized structures with the use of technique of ExperimentAided Virtual Prototyping
PublikacjaIn the paper are presented considerations concerning vibration suppression problems during milling of largesized workpieces with the use of innovative method of matching the spindle speed of cutting tool. It depends on repeatable change of the spindle speed value as soon as the optimal vibration state of the workpiece approaches. The values of dominant “peaks” in the frequency spectra and the Root Mean Square (RMS) values of time...

Fast simulationdriven design optimization of UWB bandnotch antennas
PublikacjaIn this letter, a simple yet reliable and automated methodology for rapid design optimization of ultrawideband (UWB) bandnotch antennas is presented. Our approach is a twostage procedure with the first stage focused on the design of the antenna itself, and the secondstage aiming at identification of the appropriate dimensions of the resonator with the purpose of allocating the bandnotch in the desired frequency range. For the...

Multiobjective antenna design by means of sequential domain patching
PublikacjaA simple yet robust methodology for rapid multiobjective design optimization of antenna structures has been presented. The key component of our approach is sequential domain patching of the design space which is a stencilbased search that aims at creating a path that connects the extreme Paretooptimal designs, obtained by means of singleobjective optimization runs. The patching process yields the initial approximation of the...

DESIGN ANALYSIS OF HYBRID GAS TURBINE  FUEL CELL POWER PLANT IN STATIONARY AND MARINE APPLICATIONS
PublikacjaThe paper concerns design analysis of a hybrid gas turbine power plant with a fuel cell (stack). The aim of this work was to find the most favorable variant of the medium capacity (approximately 50 MW) hybrid system. In the article, computational analysis of two variants of such a system was carried out. The analysis let to calculate capacity, efficiency of both variants and other parameters like flu gas temperature. The paper...

Reducedcost electromagneticdriven optimisation of antenna structures by means of trustregion gradientsearch with sparse Jacobian updates
PublikacjaNumerical optimisation plays more and more important role in the antenna design. Because of lack of designready theoretical models, electromagnetic (EM)simulationdriven adjustment of geometry parameters is a necessary step of the design process. At the same time, traditional parameter sweeping cannot handle complex topologies and large number of design variables. On the other hand, high computational cost of the conventional...