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Monitorowanie regionalnych zmian jonosfery z godzinnych obserwacji GPS
PublicationW nowoczesnych metodach przestrzennego wyznaczania pozycji główną rolę odgrywają globalne systemy satelitarne, pozwalające na wyznaczenie pozycji obiektu niezależnie od czasu i położenia, w najbliższym sąsiedztwie Ziemi. Obecnie znanych jest kilka satelitarnych systemów pozycjonowania o zasięgu globalnym. Wśród nich wymienić należy: GPS, GLONASS, DORIS, PRARE, w niedalekiej przyszłości - GALILEO. Wykorzystanie poszczególnych systemów,...
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Ionospheric scintillations computation using real-time GPS observations
PublicationThe following paper presents the results of quasi-real-time determination of the values of phase scintillations indices at the period of ionospheric disturbances that occurred as a consequence of the Sun flares observed on March 7 and 9, 2012. Double-frequency observations with 1-second measurement interval from the EPN (EUREF Permanent Network) network sites located at high latitudes were used for the analysis. To determine the phase...
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GPS-derived height changes in diurnal and sub-diurnal timescales
PublicationThis paper describes the research concerning precise short-time GPS solutions conducted in the Centre of Applied Geomatics, Military University of Technology, Warsaw, Poland. The data from ASG-EUPOS (Polish Active Geodetic Network) was processed using Bernese 5.0 software and EPN (EUREF Permanent Network) standards and models. In this study, the adapted 3-hour observation window is shifted every hour for obtaining hourly geocentric...
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Accuracy of Differential Phase Delay Estimation for GPS Spoofing Detection
PublicationGPS spoofing is an attack based on transmission of false signals to target receivers, in order to force the computation of incorrect time, position or velocity information. It is a threat which is recently considered with continuously growing awareness. There is a need for effective way of GPS spoofing detection. Many groups of methods are proposed in the literature. Spatial processing methods are considered to be robust in a wide...
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Integration of inertial sensors and GPS system data for underwater navigation
PublicationThe Inertial Navigation System (INS) is usually employed to determine the position of an underwater vehicles, like Remotely Operated Vehicles (ROV) and, more recently, Autonomous Underwater Vehicle (AUV). The accuracy of the position provided by the INS, which uses accelerometers and gyroscopes, deteriorates with time. An external aiding sources such as the Global Positioning System (GPS) can be employed to reduce the error growth...
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Accuracy and coverage of the modernized Polish Maritime differential GPS system
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Efektywność filtracji przestrzennej sygnałów w przeciwdziałaniu spoofingowi GPS
PublicationPrzedstawiono metodę przeciwdziałania spoofingowi GPS poprzez formowanie minimum charakterystyki kierunkowej układu antenowego. Opisano metodykę i wyniki badań tłumienia sygnałów niepożądanych w obecności szumu. Zaprezentowano rezultaty statystycznej analizy wpływu filtracji przestrzennej na tłumienie prawdziwych sygnałów GPS. W podsumowaniu wykazano korzyści wynikające z użycia przyjętej metody, w...
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Performance assessment of OpenMP constructs and benchmarks using modern compilers and multi-core CPUs
PublicationConsidering ongoing developments of both modern CPUs, especially in the context of increasing numbers of cores, cache memory and architectures as well as compilers there is a constant need for benchmarking representative and frequently run workloads. The key metric is speed-up as the computational power of modern CPUs stems mainly from using multiple cores. In this paper, we show and discuss results from running codes such as:...
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Green TPUs from Prepolymer Mixtures Designed by Controlling the Chemical Structure of Flexible Segments
PublicationThis study concerns green thermoplastic polyurethanes (TPU) obtained by controlling the chemical structure of flexible segments. Two types of bio-based polyether polyols—poly(trimethylene glycol)s—with average molecular weights ca. 1000 and 2700 Da were used (PO3G1000 and PO3G2700, respectively). TPUs were prepared via a two-step method. Hard segments consisted of 4,4?- diphenylmethane diisocyanates and the bio-based 1,4-butanodiol...
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Residual K1 and K2 Oscillations in Precise GPS Solutions: Case Study
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Method and system for disciplining a local reference oscillator by GPS 1PPS signal
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Projektowanie układów geometrycznych toru w dostosowaniu do systemu GPS
PublicationW pracy zwrócono uwagę na fakt, że zastosowanie satelitarnej techniki pomiarowej (w wariancie pomiarów ciągłych) powoduje konieczność opracowania nowej metody projektowania układów geometrycznych toru. Ponieważ kształtowanie kierunków prostych trasy na podstawie pomiarów satelitarnych nie sprawia żadnych trudności, skupiono się na kwestii projektowania odcinków położonych w łuku. Założono, że projektowanie układu geometrycznego...
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Badania odbioru sygnałów systemu GPS w obecności sygnałów zakłócających
PublicationNiniejszy artykuł poświęcono opisowi badań możliwości odbioru - w obecności zakłóceń - sygnałów transmitowanych w systemie nawigacji satelitarnej GPS. Tytułem wstępu dokonano ogólnej charakterystyki tego systemu. W części drugiej wymieniono rodzaje zagrożeń stojących przed użytkownikami usługi lokalizacji. Następnie, przedstawiono schemat stanowiska badawczego do oceny wpływu zakłóceń na odbiór sygnałów nawigacyjnych. W punkcie...
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CFD ship squat determination method validation by GPS-RTK measurements
PublicationArtykuł zawiera porównanie numerycznych obliczeń osiadania statku z wynikami badań rzeczywistych z wykorzystaniem metody GPS-RTK.
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Parallel implementation of the DGF-FDTD method on GPU Using the CUDA technology
PublicationThe discrete Green's function (DGF) formulation of the finite-difference time-domain method (FDTD) is accelerated on a graphics processing unit (GPU) by means of the Compute Unified Device Architecture (CUDA) technology. In the developed implementation of the DGF-FDTD method, a new analytic expression for dyadic DGF derived based on scalar DGF is employed in computations. The DGF-FDTD method on GPU returns solutions that are compatible...
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Zastosowanie filtracji przestrzennej do eliminacji spoofingu w systemie GPS
PublicationArtykuł podejmuje problematykę przeciwdziałania atakowi elektronicznemu typu spoofing w systemie GPS, polegającemu na niepowołanej transmisji imitacji sygnałów odbieranych z satelitów nawigacyjnych tego systemu. Odbiór sygnałów imitujących powoduje wyznaczenie nieprawidłowych wskazań czasu, położenia i prędkości odbiornika GPS. Proponowaną w artykule metodą ochrony odbiornika przed działaniem sygnałów imitujących jest adaptacyjna...
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Parallelization of large vector similarity computations in a hybrid CPU+GPU environment
PublicationThe paper presents design, implementation and tuning of a hybrid parallel OpenMP+CUDA code for computation of similarity between pairs of a large number of multidimensional vectors. The problem has a wide range of applications, and consequently its optimization is of high importance, especially on currently widespread hybrid CPU+GPU systems targeted in the paper. The following are presented and tested for computation of all vector...
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Investigation of long-range dependencies in the stochastic part of daily GPS solutions
PublicationThe long-range dependence (LRD) of the stochastic part of GPS-derived topocentric coordinates change (North, East, Up) results with relatively high autocorrelation values with a focus on self-similarity. One of the reasons for such self-similarity in the GPS time series are noises that are commonly recognised to prevail in the form of the flicker noise model. To prove the self-similarity of the stochastic part of GPS time series...
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Możliwości wyznaczania kąta nachylenia drogi z wykorzystaniem systemu GPS
PublicationW pracy przedstawiona została metoda korekty sygnału wysokości pochodzącego z systemu GPS umożliwiająca wyeliminowanie nagłych zmian wysokości, które nie występują w rzeczywistości, a są następstwem odbić lub zaniku sygnału pochodzącego z nadajników satelitarnych. Parametrem charakteryzującym zakres korekty oryginalnego sygnału jest kąt dopuszczalnego pochylenia drogi, który powinien być dobierany ze względu na analizowany typ...
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TensorHive: Management of Exclusive GPU Access for Distributed Machine Learning Workloads
PublicationTensorHive is a tool for organizing work of research and engineering teams that use servers with GPUs for machine learning workloads. In a comprehensive web interface, it supports reservation of GPUs for exclusive usage, hardware monitoring, as well as configuring, executing and queuing distributed computational jobs. Focusing on easy installation and simple configuration, the tool automatically detects the available computing...
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Wpływ tłumienia sygnałów GPS na dokładność wyznaczania współrzędnych pozycji
PublicationW artykule przedstawiono wyniki badań dotyczących wpływu tłumienia sygnałów GPS na dokładność wyznaczeń współrzędnych pozycji. Opisano stanowisko badań, przyjęte założenia oraz dokonano analizy uzyskanych rezultatów.
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Accuracy Of The GPS Positioning System In The Context Of Increasing The Number Of Satellites In The Constellation
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Runtime Visualization of Application Progress and Monitoring of a GPU-enabled Parallel Environment
PublicationThe paper presents design, implementation and real life uses of a visualization subsystem for a distributed framework for parallelization of workflow-based computations among clusters with nodes that feature both CPUs and GPUs. Firstly, the proposed system presents a graphical view of the infrastructure with clusters, nodes and compute devices along with parameters and runtime graphs of load, memory available, fan speeds etc. Secondly,...
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Parallel Background Subtraction in Video Streams Using OpenCL on GPU Platforms
PublicationImplementation of the background subtraction algorithm using OpenCL platform is presented. The algorithm processes live stream of video frames from the surveillance camera in on-line mode. Processing is performed using a host machine and a parallel computing device. The work focuses on optimizing an OpenCL algorithm implementation for GPU devices by taking into account specific features of the GPU architecture, such as memory access,...
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Parallelization of Selected Algorithms on Multi-core CPUs, a Cluster and in a Hybrid CPU+Xeon Phi Environment
PublicationIn the paper we present parallel implementations as well as execution times and speed-ups of three different algorithms run in various environments such as on a workstation with multi-core CPUs and a cluster. The parallel codes, implementing the master-slave model in C+MPI, differ in computation to communication ratios. The considered problems include: a genetic algorithm with various ratios of master processing time to communication...
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Uncertainties of geodetic velocities from permanent GPS observations:The Sudeten case study
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GPU Acceleration of Multilevel Solvers for Analysis of Microwave Components With Finite Element Method
PublicationThe letter discusses a fast implementation of the conjugate gradient iterative method with ${rm E}$-field multilevel preconditioner applied to solving real symmetric and sparse systems obtained with vector finite element method. In order to accelerate computations, a graphics processing unit (GPU) was used and significant speed-up (2.61 fold) was achieved comparing to a central processing unit (CPU) based approach. These results...
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Projekt i implementacja symulatora sygnałów GPS w technice radia programowalnego
PublicationPowszechność odbiorników systemów nawigacji satelitarnej, a zwłaszcza systemu GPS, stwarza zapotrzebowanie na symulatory sygnałów tych systemów, za pomocą których możliwe jest gruntowne testowanie wspomnianych odbiorników. W artykule przedstawiono sposób projektowania i implementacji symulatora sygnałów GPS z użyciem techniki radia programowalnego (SDR). W punkcie pierwszym zostały podane cele projektu, w punkcie drugim omówiono...
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Accuracy, Memory and Speed Strategies in GPU-based Finite-Element Matrix-Generation
PublicationThis paper presents strategies on how to optimize GPU-based finite-element matrix-generation that occurs in the finite-element method (FEM) using higher order curvilinear elements. The goal of the optimization is to increase the speed of evaluation and assembly of large finite-element matrices on a single GPU (Graphics Processing Unit) while maintaining the accuracy of numerical integration at the desired level. For this reason,...
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A Task-Scheduling Approach for Efficient Sparse Symmetric Matrix-Vector Multiplication on a GPU
PublicationIn this paper, a task-scheduling approach to efficiently calculating sparse symmetric matrix-vector products and designed to run on Graphics Processing Units (GPUs) is presented. The main premise is that, for many sparse symmetric matrices occurring in common applications, it is possible to obtain significant reductions in memory usage and improvements in performance when the matrix is prepared in certain ways prior to computation....
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GPU-Accelerated 3D Mesh Deformation for Optimization Based on the Finite Element Method
PublicationThis paper discusses a strategy for speeding up the mesh deformation process in the design-byoptimization of high-frequency components involving electromagnetic field simulations using the 3D finite element method (FEM). The mesh deformation is assumed to be described by a linear elasticity model of a rigid body; therefore, each time the shape of the device is changed, an auxiliary elasticity finite-element problem must be solved....
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Tworzenie poligonu kierunków głównych trasy kolejowej z wykorzystaniem pomiarów GPS
PublicationW pracy przedstawiono kolejny moduł opracowywanego w Politechnice Gdańskiej programu komputerowego SATTRACK do wizualizacji, oceny i projektowania trasy kolejowej, dostosowanego do techniki ciągłych pomiarów satelitarnych. Jest to moduł TRACK_POL, służący do tworzenia poligonu kierunków głównych trasy kolejowej. Zapisane w pliku tekstowym współrzędne prostych wykorzystuje się do wyznaczenia ich równań w państwowym układzie odniesień...
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Selected problems of determining the course of railway routes by use of GPS network solution
PublicationW 2009 roku Politechnika Gdańska rozpoczęła prace nad wykorzystaniem ciągłych pomiarów pozycji systemów geodezji satelitarnej dla wyznaczania przebiegu trasy kolejowej z wykorzystaniem fazowych metod GPS opartych o serwis NAVGEO polskiej Aktywnej Sieci Geodezyjnej ASG-EUPOS. W celu eliminacji błędów przypadkowych wpływających na dokładność wyznaczenia trasy kolejowej w następnym roku zespół przeprowadził dwie kampanie pomiarowe...
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Integration of inertial sensors and GPS system data for the personal navigation in urban area
PublicationGPS and Inertial Navigation Systems (INS) have complementary properties and they are therefore well suited for integration. The integrated solution offers better long-term accuracy than a stand-alone INS and better integrity, availability and continuity or a stand-alone GPS receiver, making it suitable for demanding applications. The complementary features of INS and GPS are the main reasons why integrated GPS/INS systems are becoming...
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Data Integration from GPS and Inertial Navigation Systems for Pedestrians in Urban Area
PublicationThe GPS system is widely used in navigation and the GPS receiver can offer long-term stable absolute positioning information. The overall system performance depends largely on the signal environments. The position obtained from GPS is often degraded due to obstruction and multipath effect caused by buildings, city infrastructure and vegetation, whereas, the current performance achieved by inertial navigation systems (INS) is still...
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GPU based implementation of Temperature-Vegetation Dryness Index for AVHRR3 Satellite Data
PublicationPaper presents an implementation of TVDI (Temperature-Vegetation-Dryness Index) algorithm on GPU (Graphics Processing Unit). Calculation of this index is based on LST (Land Surface Temperature) and NDVI (Normalized Difference Vegetation Index). Discussed results are based on multi-spectral imagery retrieved from AVHRR3 sensors for area of Poland. All phases of TVDI implementation on GPU are modified in respect to CUDA platform....
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Performance evaluation of GPS anti-spoofing system based on antenna array processing
PublicationThis article concerns the problem of detection and mitigation of spoofing attacks in Global Navigation Satellite Systems. First, background information about spoofing and its possible countermeasures is provided. Next, concept of a novel GPS anti-spoofing system based on antenna array processing is presented and implementation of prototype of this system is described. The third section outlines the performance evaluation of proposed...
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A multithreaded CUDA and OpenMP based power‐aware programming framework for multi‐node GPU systems
PublicationIn the paper, we have proposed a framework that allows programming a parallel application for a multi-node system, with one or more GPUs per node, using an OpenMP+extended CUDA API. OpenMP is used for launching threads responsible for management of particular GPUs and extended CUDA calls allow to manage CUDA objects, data and launch kernels. The framework hides inter-node MPI communication from the programmer who can benefit from...
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Optimization of Data Assignment for Parallel Processing in a Hybrid Heterogeneous Environment Using Integer Linear Programming
PublicationIn the paper we investigate a practical approach to application of integer linear programming for optimization of data assignment to compute units in a multi-level heterogeneous environment with various compute devices, including CPUs, GPUs and Intel Xeon Phis. The model considers an application that processes a large number of data chunks in parallel on various compute units and takes into account computations, communication including...
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How to render FDTD computations more effective using agraphics accelerator.
PublicationGraphics processing units (GPUs) for years have been dedicated mostly to real time rendering. Recently leading GPU manufactures have extended their research area and decided to support also graphics computing. In this paper, we describe an impact of new GPU features on development process of an efficient finite difference time domain (FDTD) implementation.
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Implementation of algebraic procedures on the GPU using CUDA architecture on the example of generalized eigenvalue problem
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Wybrane problemy wyznaczania przebiegu trasy kolejowej z wykorzystaniem rozwiązań sieciowych GPS
PublicationW pracy zwrócono uwagę na niewystarczającą skuteczność stosowanych dotychczas na kolei metod kształtowania osi toru w płaszczyźnie poziomej. Sformułowano tezę, że możliwości radykalnej poprawy sytuacji stwarza metoda ciągłych pomiarów satelitarnych GPS, zastosowana przez zespół naukowy z Politechniki Gdańskiej. Przedstawiono ogólna charakterystykę pomiarów satelitarnych i opisano przebieg przeprowadzonych badań terenowych. Przeprowadzone...
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Block Conjugate Gradient Method with Multilevel Preconditioning and GPU Acceleration for FEM Problems in Electromagnetics
PublicationIn this paper a GPU-accelerated block conjugate gradient solver with multilevel preconditioning is presented for solving large system of sparse equations with multiple right hand-sides (RHSs) which arise in the finite-element analysis of electromagnetic problems. We demonstrate that blocking reduces the time to solution significantly and allows for better utilization of the computing power of GPUs, especially when the system matrix...
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A strategy for GPS data processing in a precise local network during high solar activity
PublicationThis paper presents the analyses connected with reduction of errors from ionospheric refraction using GPS data from local satellite networks. This is particularly essential during rising solar activity. The Bernese GPS Software v. 4.2 was used, as an analytical tool. The test data included measurements from a geodynamic network SUDETES situated in the Sudety Mountains across the border between the Czech Republic and Poland. A local...
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Intercomparison of TEC obtained from the IRI model to the one derived from GPS measurements
PublicationIRI (International Reference Ionosphere) is a well-known standard of the ionosphere, but nowadays GPS permanent observations are also the base of the regional and global ionosphere models. In this paper, comparison of TEC (Total Electron Content) derived from the IRI model to the global TEC parameters derived from GPS measurements is presented. Global TEC maps show, that GPS derived ionosphere models, in opposition to the IRI,...
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Performance Evaluation of Selected Parallel Object Detection and Tracking Algorithms on an Embedded GPU Platform
PublicationPerformance evaluation of selected complex video processing algorithms, implemented on a parallel, embedded GPU platform Tegra X1, is presented. Three algorithms were chosen for evaluation: a GMM-based object detection algorithm, a particle filter tracking algorithm and an optical flow based algorithm devoted to people counting in a crowd flow. The choice of these algorithms was based on their computational complexity and parallel...
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Analiza dokładności wyznaczania różnicowych opóźnień fazowych w systemie wykrywania spoofingu GPS
PublicationSpoofing GPS jest atakiem polegającym na nadawaniu fałszywych sygnałów do odbiornika GPS, w celu wyznaczenia przez niego nieprawidłowych informacji o położeniu, prędkości i czasie. Istnieje potrzeba opracowania skutecznych metod jego wykrywania. Niniejszy artykuł opisuje metodę opartą na pomiarach opóźnień fazowych w układzie wieloantenowym. Przedstawiono analizę dotyczącą dokładności i precyzji estymacji różnic fazy, ustalono...
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Implementation of FDTD-compatible Green's function on heterogeneous CPU-GPU parallel processing system
PublicationThis paper presents an implementation of the FDTD-compatible Green's function on a heterogeneous parallel processing system. The developed implementation simultaneously utilizes computational power of the central processing unit (CPU) and the graphics processing unit (GPU) to the computational tasks best suited to each architecture. Recently, closed-form expression for this discrete Green's function (DGF) was derived, which facilitates...
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Performance and Energy Aware Training of a Deep Neural Network in a Multi-GPU Environment with Power Capping
PublicationIn this paper we demonstrate that it is possible to obtain considerable improvement of performance and energy aware metrics for training of deep neural networks using a modern parallel multi-GPU system, by enforcing selected, non-default power caps on the GPUs. We measure the power and energy consumption of the whole node using a professional, certified hardware power meter. For a high performance workstation with 8 GPUs, we were...
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Communication and Load Balancing Optimization for Finite Element Electromagnetic Simulations Using Multi-GPU Workstation
PublicationThis paper considers a method for accelerating finite-element simulations of electromagnetic problems on a workstation using graphics processing units (GPUs). The focus is on finite-element formulations using higher order elements and tetrahedral meshes that lead to sparse matrices too large to be dealt with on a typical workstation using direct methods. We discuss the problem of rapid matrix generation and assembly, as well as...