227,202 research outputs found
Modelling Chinese Smart Grid: A Stochastic Model Checking Case Study
Cyber-physical systems integrate information and communication technology
functions to the physical elements of a system for monitoring and controlling
purposes. The conversion of traditional power grid into a smart grid, a
fundamental example of a cyber-physical system, raises a number of issues that
require novel methods and applications. In this context, an important issue is
the verification of certain quantitative properties of the system. In this
technical report, we consider a specific Chinese Smart Grid implementation and
try to address the verification problem for certain quantitative properties
including performance and battery consumption. We employ stochastic model
checking approach and present our modelling and analysis study using PRISM
model checker
SzámĂtĂłhálĂł alkalmazások teljesĂtmĂ©nyanalĂzise Ă©s optimalizáciĂłja = Performance analysis and optimisation of grid applications
SzámĂtĂłhálĂłn (griden) futĂł alkalmazások, elsĹ‘sorban workflow-k hatĂ©kony vĂ©grehajtására kerestĂĽnk Ăşjszerű megoldásokat a grid teljesĂtmĂ©nyanalĂzis Ă©s optimalizáciĂł terĂĽletĂ©n. ElkĂ©szĂtettĂĽk a Mercury monitort a grid teljesĂtmĂ©nyanalĂzis követelmĂ©nyeit figyelembe vĂ©ve. A párhuzamos programok monitorozására alkalmas GRM monitort integráltuk a reláciĂłs adatmodell alapĂş R-GMA grid informáciĂłs rendszerrel, illetve a Mercury monitorral. ElkĂ©szĂĽlt a Pulse, Ă©s a Prove vizualizáciĂłs eszköz grid teljesĂtmĂ©nyanalĂzist támogatĂł verziĂłja. ElkĂ©szĂtettĂĽnk egy state-of-the-art felmĂ©rĂ©st grid teljesĂtmĂ©nyanalĂzis eszközökrĹ‘l. Kidolgoztuk a P-GRADE rendszer workflow absztrakciĂłs rĂ©tegĂ©t, melyhez kapcsolĂłdĂłan elkĂ©szĂĽlt a P-GRADE portál. Ennek segĂtsĂ©gĂ©vel a felhasználĂłk egy web böngĂ©szĹ‘n keresztĂĽl szerkeszthetnek Ă©s hajthatnak vĂ©gre workflow alkalmazásokat számĂtĂłhálĂłn. A portál kĂĽlönbözĹ‘ számĂtĂłhálĂł implementáciĂłkat támogat. LehetĹ‘sĂ©get biztosĂt informáciĂł gyűjtĂ©sĂ©re teljesĂtmĂ©nyanalĂzis cĂ©ljábĂłl. Megvizsgáltuk a portál erĹ‘forrás brĂłkerekkel valĂł egyĂĽttműködĂ©sĂ©t, felkĂ©szĂtettĂĽk a portált a sikertelen futások javĂtására. A vĂ©grehajtás optimalizálása megkövetelheti az alkalmazás egyes rĂ©szeinek áthelyezĂ©sĂ©t más erĹ‘forrásokra. Ennek támogatására továbbfejlesztettĂĽk a P-GRADE alkalmazások naplĂłzhatĂłságát, Ă©s illesztettĂĽk a Condor feladatĂĽtemezĹ‘jĂ©hez. Sikeresen kapcsoltunk a rendszerhez egy terhelĂ©s elosztĂł modult, mely kĂ©pes a terheltsĂ©gĂ©tĹ‘l fĂĽggĹ‘en áthelyezni a folyamatokat. | We investigated novel approaches for performance analysis and optimization for efficient execution of grid applications, especially workflows. We took into consideration the special requirements of grid performance analysis when elaborated Mercury, a grid monitoring infrastructure. GRM, a performance monitor for parallel applications, has been integrated with R-GMA, a relational grid information system and Mercury as well. We developed Pulse and Prove visualisation tools for supporting grid performance analysis. We wrote a comprehensive state-of-the art survey of grid performance tools. We designed a novel abstraction layer of P-GRADE supporting workflows, and a grid portal. Users can draft and execute workflow applications in the grid via a web browser using the portal. The portal supports multiple grid implementations and provides monitoring capabilities for performance analysis. We tested the integration of the portal with grid resource brokers and also augmented it with some degree of fault-tolerance. Optimization may require the migration of parts of the application to different resources and thus, it requires support for checkpointing. We enhanced the checkpointing facilities of P-GRADE and coupled it to Condor job scheduler. We also extended the system with a load balancer module that is able to migrate processes as part of the optimization
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A distributed analysis and monitoring framework for the compact Muon solenoid experiment and a pedestrian simulation
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The design of a parallel and distributed computing system is a very complicated task. It requires a detailed understanding of the design issues and of the theoretical and practical aspects of their solutions. Firstly, this thesis discusses in detail the major concepts and components required to make parallel and distributed computing a reality. A multithreaded and distributed framework capable of analysing the simulation data produced by a pedestrian simulation software was developed. Secondly, this thesis discusses the origins and fundamentals of Grid computing and the motivations for its use in High Energy Physics. Access to the data produced by the Large Hadron Collider (LHC) has to be provided for more than five thousand scientists all over the world. Users who run analysis jobs on the Grid do not necessarily have expertise in Grid computing. Simple, userfriendly and reliable monitoring of the analysis jobs is one of the key components of the operations of the distributed analysis; reliable monitoring is one of the crucial components of the Worldwide LHC Computing Grid for providing the functionality and performance that is required by the LHC experiments. The CMS Dashboard Task Monitoring and the CMS Dashboard Job Summary monitoring applications were developed to serve the needs of the CMS community
Characterization of non-intentional emissions from distributed energy resources up to 500 kHz: A case study in Spain
Narrow Band Power Line Communications (NB-PLC) systems are currently used for smart metering and power quality monitoring as a part of the Smart Grid (SG) concept. However, non-intentional emissions generated by the devices connected to the grid may sometimes disturb the communications and isolate metering equipment. Though some research works have been recently developed to characterize these emissions, most of them have been limited to frequencies below 150 kHz and they are mainly focused on in-house electronic appliances and lightning devices. As NB-PLC can also be allocated in higher frequencies up to 500 kHz, there is still a lack of analysis in this frequency range, especially for emissions from Distributed Energy Resources (DERs). The identification and characterization of the emissions is essential to develop solutions that avoid a negative impact on the proper performance of NB-PLC.
In this work, the non-intentional emissions of different types of DERs composing a representative microgrid have been measured in the 35–500 kHz frequency range and analyzed both in time and frequency domains. Different working conditions and coupling and commutation procedures to mains are considered in the analysis. Results are then compared to the limits recommended by regulatory bodies for spurious emissions from communication systems in this frequency band, as no specific limits for DERs have been established. Field measurements show clear differences in the characteristics of non-intentional emissions for different devices, working conditions and coupling procedures and for frequencies below and above 150 kHz. Results of this study demonstrate that a further characterization of the potential emissions from the different types of DERs connected to the grid is required in order to guarantee current and future applications based on NB-PLC.This work has been financially supported in part by the Basque
Government (Elkartek program)
Synchronized measurement data conditioning and real-time applications
Phasor measurement units (PMU), measuring voltage and current phasor with synchronized timestamps, is the fundamental component in wide-area monitoring systems (WAMS) and reveals complex dynamic behaviors of large power systems. The synchronized measurements collected from power grid may degrade due to many factors and impacts of the distorted synchronized measurement data are significant to WAMS. This dissertation focus on developing and improving applications with distorted synchronized measurements from power grid. The contributions of this dissertation are summarized below. In Chapter 2, synchronized frequency measurements of 13 power grids over the world, including both mainland and island systems, are retrieved from Frequency Monitoring Network (FNET/GridEye) and the statistical analysis of the typical power grids are presented. The probability functions of the power grid frequency based on the measurements are calculated and categorized. Developments of generation trip/load shedding and line outage events detection and localization based on high-density PMU measurements are investigated in Chapters 3 and 4 respectively. Four different types of abnormal synchronized measurements are identified from the PMU measurements of a power grid. The impacts of the abnormal synchronized measurements on generation trip/load shedding events detection and localization are evaluated. A line outage localization method based on power flow measurements is proposed to improve the accuracy of line outage events location estimation. A deep learning model is developed to detect abnormal synchronized measurements in Chapter 5. The performance of the model is evaluated with abnormal synchronized measurements from a power grid under normal operation status. Some types of abnormal synchronized measurements in the testing cases are recently observed and reported. An extensive study of hyper-parameters in the model is conducted and evaluation metrics of the model performance are presented. A non-contact synchronized measurements study using electric field strength is investigated in Chapter 6. The theoretical foundation and equation derivations are presented. The calculation process for a single circuit AC transmission line and a double circuit AC transmission line are derived. The derived method is implemented with Matlab and tested in simulation cases
Mobile Computing in Physics Analysis - An Indicator for eScience
This paper presents the design and implementation of a Grid-enabled physics
analysis environment for handheld and other resource-limited computing devices
as one example of the use of mobile devices in eScience. Handheld devices offer
great potential because they provide ubiquitous access to data and
round-the-clock connectivity over wireless links. Our solution aims to provide
users of handheld devices the capability to launch heavy computational tasks on
computational and data Grids, monitor the jobs status during execution, and
retrieve results after job completion. Users carry their jobs on their handheld
devices in the form of executables (and associated libraries). Users can
transparently view the status of their jobs and get back their outputs without
having to know where they are being executed. In this way, our system is able
to act as a high-throughput computing environment where devices ranging from
powerful desktop machines to small handhelds can employ the power of the Grid.
The results shown in this paper are readily applicable to the wider eScience
community.Comment: 8 pages, 7 figures. Presented at the 3rd Int Conf on Mobile Computing
& Ubiquitous Networking (ICMU06. London October 200
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