Search results for "Distributed"

showing 10 items of 1260 documents

Optical frequency domain reflectometer distributed sensing using microstructured pure silica optical fibers under radiations

2016

International audience; We investigated the capability of micro-structured optical fibers to develop multi-functional, remotely-controlled, Optical Frequency Domain Reflectometry (OFDR) distributed fiber based sensors to monitor temperature in nuclear power plants or high energy physics facilities. As pure-silica-core fibers are amongst the most radiation resistant waveguides, we characterized the response of two fibers with the same microstructure, one possessing a core elaborated with F300 Heraeus rod representing the state-of-the art for such fiber technology and one innovative sample based on pure sol-gel silica. Our measurements reveal that the Xray radiations do not affect the capaci…

Nuclear and High Energy PhysicsMaterials scienceOptical fiberOptical time-domain reflectometerRayleigh scattering01 natural scienceslaw.invention010309 opticsOpticsZero-dispersion wavelengthlaw0103 physical sciencesRayleighElectrical and Electronic EngineeringNuclear and High Energy Physic[PHYS]Physics [physics]RadiationOptical fiber sensor010308 nuclear & particles physicsbusiness.industryOptical fiber sensorsOptique / photoniqueMicrostructured optical fiberDistributed acoustic sensingradiationNuclear Energy and EngineeringFiber optic sensor[SPI.OPTI]Engineering Sciences [physics]/Optics / PhotonicOptoelectronicsbusinessHard-clad silica optical fiberPhotonic-crystal fiber
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Evaluation of Distributed OFDR-Based Sensing Performance in Mixed Neutron/Gamma Radiation Environments

2017

We report the study of a radiation resistant single mode optical fiber doped with fluorine exposed to mixed neutron and $\gamma $ -radiation up to $10^{17}$ n/cm2 fluence and >2 MGy dose to evaluate its performances when used as the sensing element of a distributed Optical Frequency Domain Reflectometry (OFDR). The use of complementary spectroscopic techniques highlights some differences between the responses of solely $\gamma $ -radiation (10 MGy) or mixed neutron and $\gamma $ ( $10^{17}$ n/cm $^{2}+>2$ MGy) irradiated samples. Those differences are linked to the defect generation rather than to structural changes of the ${a}$ -SiO2 host matrix. We show that a modification of the refracti…

Nuclear and High Energy PhysicsOptical fiberMaterials scienceAstrophysics::High Energy Astrophysical Phenomena02 engineering and technologyRadiationRayleigh scattering01 natural sciencesFluencelaw.inventionsymbols.namesake020210 optoelectronics & photonicsOpticsNeutron fluxlaw0103 physical sciences0202 electrical engineering electronic engineering information engineeringNeutronIrradiationElectrical and Electronic EngineeringRayleigh scatteringOptical Frequency Domain Reflectometry Nuclear and High Energy PhysicsNeutronsRadiation010308 nuclear & particles physicsbusiness.industryOptical fiber sensorsSingle-mode optical fiberOptique / photoniqueneutrons gamma radiationNuclear Energy and Engineeringsymbols[SPI.OPTI]Engineering Sciences [physics]/Optics / PhotonicAtomic physicsbusinessoptical fiber distributed sensor
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A time-of-flight correction procedure for fast-timing data of recoils with varying implantation positions at a spectrometer focal plane

2019

Abstract Fast-timing measurements at the focal plane of a separator can suffer from poor timing resolution. This is due to the variations in time-of-flight (ToF) for photons travelling to a given detector, which arise from the changes in the implantation positions of the recoil nuclei emitting the γ rays of interest. In order to minimise these effects on timing measurements, a procedure is presented that improves fast-timing data by performing ToF corrections on an event-by-event basis. This method was used to correct data collected with an array of eight LaBr 3 detectors, which detected γ rays from spatially distributed 138Gd recoil-implants at the focal plane of the Recoil-Ion-Transport-U…

Nuclear and High Energy PhysicsPhotonGeneralised-centroid-difference methodtutkimuslaitteetspektrometritStandard deviation138GdRecoilgeneralised-centroid-difference methodDistributed sourceNuclear ExperimentNuclear-state lifetimesInstrumentationdetectorsPhysicsnuclear-state lifetimesta114Spectrometerfast-timingDetectorCentroidFast-timingLaBr3Computational physicsTime of flightCardinal pointdistributed sourceydinfysiikkaNuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
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Radiation Hardened Optical Frequency Domain Reflectometry Distributed Temperature Fiber-Based Sensors

2015

International audience; We study the performance of Optical Frequency Domain Reflectometry (OFDR) distributed temperature sensors using radiation resistant single-mode optical fibers. In situ experiments under 10 keV X-rays exposure up to 1 MGy( SiO 2 ) were carried out with an original setup that allows to investigate combined temperature and radiation effects on the sensors within a temperature range from 30 ° C to 250 ° C. Obtained results demonstrate that optical fiber sensors based on Rayleigh technique are almost unaffected by radiation up to the explored doses. We show that a pre-thermal treatment stabilize the sensor performance increasing the accuracy on temperature measurement fro…

Nuclear and High Energy Physicsoptical fiberOptical fiberMaterials scienceRadiation effectsRadiationRayleigh scatteringTemperature measurementlaw.inventionDistributed sensingsymbols.namesakeOpticslawOptical fibers[PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det]ElectroniqueRayleigh scatteringElectrical and Electronic EngineeringReflectometryNuclear and High Energy PhysicFiber sensorsradiation effectbusiness.industryfiber sensorAtmospheric temperature rangeDistributed acoustic sensingNuclear Energy and EngineeringFiber optic sensor[SPI.OPTI]Engineering Sciences [physics]/Optics / PhotonicsymbolsOptoelectronicsbusiness
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The laser and optical system for the RIBF-PALIS experiment

2017

Abstract This paper describes the laser and optical system for the Parasitic radioactive isotope (RI) beam production by Laser Ion-Source (PALIS) in the RIKEN fragment separator facility. This system requires an optical path length of 70 m for transporting the laser beam from the laser light source to the place for resonance ionization. To accomplish this, we designed and implemented a simple optical system consisting of several mirrors equipped with compact stepping motor actuators, lenses, beam spot screens and network cameras. The system enables multi-step laser resonance ionization in the gas cell and gas jet via overlap with a diameter of a few millimeters, between the laser photons an…

Nuclear and High Energy PhysicsspektroskopiaPhysics::Optics01 natural sciencesBeam parameter productlaw.inventionVertical-cavity surface-emitting laserLaser linewidthOpticslaw0103 physical sciencesPhysics::Atomic PhysicsLaser power scaling010306 general physicsInstrumentationPhysicsDistributed feedback laserta114010308 nuclear & particles physicsbusiness.industryFar-infrared lasergas cellLaserlasertekniikkaLaser Ion Sourcegas jetlaser spectroscopyPhysics::Accelerator PhysicsLaser beam qualitylaser resonance ionizationbusinessydinfysiikkaNuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
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IGISOL control system modernization

2016

Abstract Since 2010, the IGISOL research facility at the Accelerator laboratory of the University of Jyvaskyla has gone through major changes. Comparing the new IGISOL4 facility to the former IGISOL3 setup, the size of the facility has more than doubled, the length of the ion transport line has grown to about 50 m with several measurement setups and extension capabilities, and the accelerated ions can be fed to the facility from two different cyclotrons. The facility has evolved to a system comprising hundreds of manual, pneumatic and electronic devices. These changes have prompted the need to modernize also the facility control system taking care of monitoring and transporting the ion beam…

Nuclear and High Energy Physicsta114ta213010308 nuclear & particles physicsComputer sciencesoftwareMaintainabilityIndustrial control systemsystem architecture01 natural scienceslaw.inventionData acquisitionlawControl system0103 physical sciencesSystems engineeringSystems architecturehardwareElectronicsEPICScontrol system010306 general physicsDistributed control systemInstrumentationRemote controlNuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
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Partial differential equations governed by accretive operators

2012

The theory of nonlinear semigroups in Banach spaces generated by accretive operators has been very useful in the study of many nonlinear partial differential equations Such a theory is fundamentally based in the Crandall-Liggett Theorem and in the contributions of Ph. Benilan. In this paper, after outlining some of the main points of this theory, we present some of the applications to some nonlinear partial differential equations that appear in different fields of Science.

Numerical AnalysisPure mathematicsConstant coefficientsControl and OptimizationApplied MathematicsMathematical analysisOperator theoryFourier integral operatorStochastic partial differential equationNonlinear systemDistributed parameter systemModeling and SimulationC0-semigroupNumerical partial differential equationsMathematicsSeMA Journal
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Unified Parallel C++

2018

Abstract Although MPI is commonly used for parallel programming on distributed-memory systems, Partitioned Global Address Space (PGAS) approaches are gaining attention for programming modern multi-core CPU clusters. They feature a hybrid memory abstraction: distributed memory is viewed as a shared memory that is partitioned among nodes in order to simplify programming. In this chapter you will learn about Unified Parallel C++ (UPC++), a library-based extension of C++ that gathers the advantages of both PGAS and Object Oriented paradigms. The examples included in this chapter will help you to understand the main features of PGAS languages and how they can simplify the task of programming par…

Object-oriented programmingSource codeComputer sciencemedia_common.quotation_subjectParallel computingSoftware_PROGRAMMINGTECHNIQUESShared memoryAsynchronous communicationUnified Parallel CDistributed memoryPartitioned global address spacecomputercomputer.programming_languageAbstraction (linguistics)media_common
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Cultural institutions as agents of urban and community regeneration in the (post-)pandemic city. The case of the «Laboratorio Zen Insieme» in Palermo

2022

Although all cities in the world have been affected by the COVID-19 pandemic, its impacts on the territories, yet to be understood, are unevenly distributed, revealing extremely varied imbalances depending on the places. However, it is clear that the virus and its variants have aggravated pre-existing socio-spatial inequalities, creating new ones and bringing attention back to those implications between space, planning, public health and citizenship that are at the origins of contemporary urbanism. In a reference framework in which the crisis is globalized but unequal and in the absence of a welfare system capable of responding to the urgencies of the most marginalized social contexts and g…

Olsen 2018Settore ICAR/21 - UrbanisticaSettore M-GGR/01 - GeografiaSacco and Blessi 2009). In the current (post-) pandemic context and through the lens of a southern European perspective the purpose of this article is to critically reflect about the role of culture as possible vehicle of urban and community regeneration. In particular we will focus on the activities of the no profit organization «Laboratorio Zen Insieme» in ZEN2 one of the last large popular and peripheral neighborhoods built in Palermo at the end of 80s in order to explore and understand how cultural practices work as agent of urban and social transformation capable of addressing emerging issues especially in the pandemic scenario we are experiencing. Thecasestudy has been conducted through analysis of documents participative observations (Honer and Hitzler 2015) and qualitative in-depth interviews with key actors involved in the conception organization and management of the activities carried out by Laboratorio Zen Insieme with representatives of local institutions and non-formal conversations with participants of the workshops heldin the neighborhood. The experience we narrate finds that cultural practices have re-conceptualized their design and functions as strategies of urban and community regeneration and at the same time have contributed to answer to emergent issues in developing proximity and local based strategies facing up to problems inherent civil rights educationalpoverty socio-spatial justice and have changed the image and identity of urban places they inhabit.In this sense the research provides a framework for development of strategies and legitimization for cultural practices and a point of discussionabouttheirrolein urban development.Although all cities in the world have been affected by the COVID-19 pandemic its impacts on the territories yet to be understood are unevenly distributed revealing extremely varied imbalances depending on the places. However it is clear that the virus and its variants have aggravated pre-existing socio-spatial inequalities creating new ones and bringing attention back to those implications between space planning public health and citizenship that are at the origins of contemporary urbanism. In a reference framework in which the crisis is globalized but unequal and in the absence of a welfare system capable of responding to the urgencies of the most marginalized social contexts and groups a response to the new social and individual needs has been offered by cultural institutions that play a role of territorial agency often independently or in the absence of political institutions. Far from the idea of entertainment and divertissement it is in fact increasingly clear how the practices of cultural innovation experimenting with various forms of action and participation can in some cases play a fundamental role in the processes of social cohesion and community building representing an antidote to the worsening of the phenomena of marginalization and socio-spatial inequalities within cities and territories (Colantonio and Dixon 2011
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Scheduling of Real-Time Networks with a Column Generation Approach

2013

We present an algorithm based on column generation for the real-time scheduling problem of allocating periodic tasks to electronic control units in multiple subsystems connected by a global bus. The allocation has to ensure that tasks can be scheduled, and messages between tasks in different subsystems can be transmitted over the global bus and meet their deadlines. Also tasks and messages occurring in a task chain must be scheduled in a way such that the sequence of execution meets their end-to-end deadline. We show that our approach computes the optimal allocation in our model and due to the column generation approach early provides lower bounds on the optimal value.

On columnRate-monotonic schedulingJob shop schedulingComputer scienceDistributed computingOptimal allocationColumn generationReal time networksDeadline-monotonic schedulingScheduling (computing)
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