Search results for "grid"
showing 10 items of 792 documents
Distributed Data Collection for the ATLAS EventIndex
2015
The ATLAS EventIndex contains records of all events processed by ATLAS, in all processing stages. These records include the references to the files containing each event (the GUID of the file) and the internal “pointer” to each event in the file. This information is collected by all jobs that run at Tier-0 or on the Grid and process ATLAS events. Each job produces a snippet of information for each permanent output file. This information is packed and transferred to a central broker at CERN using an ActiveMQ messaging system, and then is unpacked, sorted and reformatted in order to be stored and catalogued into a central Hadoop server. This contribution describes in detail the Producer/Consu…
Challenges of the ATLAS Monte Carlo production during run 1 and beyond
2013
In this paper we will review the ATLAS Monte Carlo production setup including the different production steps involved in full and fast detector simulation. A report on the Monte Carlo production campaigns during run 1 and long shutdown 1 will be presented, including details on various performance aspects. Important improvements in the work flow and software will be highlighted. Besides standard Monte Carlo production for data analyses at 7 and 8 TeV, the production accommodates for various specialised activities. These ranges from extended Monte Carlo validation, Geant4 validation, pileup simulation using zero bias data and production for various upgrade studies. The challenges of these act…
Preliminary Tests On A Miniaturized Hybrid Pv-Pemfc System
2007
A regenerative hybrid PV-PEMFC low power system is a suitable solution to replace batteries and to supply small electric devices placed in remote areas with no grid connection. Such a system was designed and built including a PV array, electrolyzer, PEMFC stack (6We) and hydrogen storage tank. As well known a hybrid PV-PEMFC energy system may represent a reliable solution to the renewable energy storage problem. Hydrogen produced by such a system is a clean fuel, suitable to replace traditional fuels which contain carbon damaging the environment. The paper reports results of a preliminary, non-dynamic experimental analysis performed on the system in order to study the effects of the anode p…
A Flux Method for the Numerical Solution of the Stochastic Collection Equation
1998
Abstract A new mass conservative flux method is presented for the numerical solution of the stochastic collection equation. The method consists of a two-step procedure. In the first step the mass distribution of drops with mass x′ that have been newly formed in a collision process is entirely added to grid box k of the numerical grid mesh with xk ⩽ x′ ⩽ xk+1. In the second step a certain fraction of the water mass in grid box k is transported to k + 1. This transport is done by means of an advection procedure. Different numerical test runs are presented in which the proposed method is compared with the Berry–Reinhardt scheme. These tests show a very good agreement between the two approaches…
Effects of post-filtering in grid-synchronization algorithms under grid faults
2018
Abstract The spread of distributed generation systems has reinforced concerns and requirements on grid-tied power converters. The synchronization with the utility voltage vector is a major concern. In the literature, algorithms based on Phase Locked Loops are extensively presented. In spite of adequate performances under ideal and balanced grid conditions, under grid faults great inaccuracies arise. Shortcomings are overcome by advanced algorithms at the expenses of the complexity and computational cost. In this paper, grid synchronization algorithms are addressed. A solution is proposed by introducing a new post-filter stage in a Decoupled Double Synchronous Reference Frame not affecting, …
Off the grid. Touristische Idyllen der Entnetzung
2021
Abstract The article examines the relation of tourism and idyll in regard to the mediation of the tourist experience. Digital detox tourism and off grid tourism are two examples of contemporary tourism – including their respective practices and ways of promotion – that associate certain cultural stereotypes with the idyll. While digital detox tourism promises independence from the digital world, off grid tourism detaches the tourist from infrastructure and supplies. Paradoxically, the advertising of these types of ‘disconnection’ makes use of the same linked infrastructures that tourists are bound to leave behind. Thus, this article reveals the ways in which digital detox tourism and off gr…
Multifacet structure of observed reconstructed integral images.
2005
Three-dimensional images generated by an integral imaging system suffer from degradations in the form of grid of multiple facets. This multifacet structure breaks the continuity of the observed image and therefore reduces its visual quality. We perform an analysis of this effect and present the guidelines in the design of lenslet imaging parameters for optimization of viewing conditions with respect to the multifacet degradation. We consider the optimization of the system in terms of field of view, observer position and pupil function, lenslet parameters, and type of reconstruction. Numerical tests are presented to verify the theoretical analysis.
An assessment of the differences between spatial resolution and grid size for the SMAP enhanced soil moisture product over homogeneous sites
2018
Abstract Satellite-based passive microwave remote sensing typically involves a scanning antenna that makes measurements at irregularly spaced locations. These locations can change on a day to day basis. Soil moisture products derived from satellite-based passive microwave remote sensing are usually resampled to a fixed Earth grid that facilitates their use in applications. In many cases the grid size is finer than the actual spatial resolution of the observation, and often this difference is not well understood by the user. Here, this issue was examined for the Soil Moisture Active Passive (SMAP) enhanced version of the passive-based soil moisture product, which has a grid size of 9-km and …
System Stability of a Small Island's Network with Different Levels of Wind Power Penetration
2018
The reduction of the inertial response of the generation system has been one of the main obstacles to the penetration of high sharing of renewable energy sources in islanded systems. This issue can be solved thanks to innovative control that makes wind turbines able to provide the so-named synthetic inertia. The paper investigates some scenarios with different levels of wind power penetration in a small island whose grid is not supplied by the main grid, by the use of the software NEPLAN 360, simulating the wind power plants accordingly to the standard IEC 61400-27. The aim of the paper is to assess the maximum level of penetration in the island of wind generation, with traditional control …
An Analysis of the Intertial Response of Small Isolated Power Systems in Presence of Generation from Renewable Energy Sources
2018
Renewable Energy Sources are posing critical issues related to the mining of power systems stability, essentially due to a decrement of the inertial response during system's contingencies. As a consequence, to preserve the security and the reliability of the system, it is necessary to adopt new frequency adjustments mechanisms. This issue becomes particularly critical in isolated power systems, like those of small islands not supplied by the main grid, in the case of high shares of production from unpredictable renewabies such as photovoitaic and wind sources. In this framework, the present work deals with the analysis of the variation of the inertia time constant of a small island in vario…