956 research outputs found

    CMS workflow execution using intelligent job scheduling and data access strategies

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    Complex scientific workflows can process large amounts of data using thousands of tasks. The turnaround times of these workflows are often affected by various latencies such as the resource discovery, scheduling and data access latencies for the individual workflow processes or actors. Minimizing these latencies will improve the overall execution time of a workflow and thus lead to a more efficient and robust processing environment. In this paper, we propose a pilot job concept that has intelligent data reuse and job execution strategies to minimize the scheduling, queuing, execution and data access latencies. The results have shown that significant improvements in the overall turnaround time of a workflow can be achieved with this approach. The proposed approach has been evaluated, first using the CMS Tier0 data processing workflow, and then simulating the workflows to evaluate its effectiveness in a controlled environment. © 2011 IEEE

    Sphenopalatine-sphenopalatine anastomosis: a unique cause of intractable epistaxis, safely treated with microcatheter embolization: a case report

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    Epistaxis is the most common emergency presenting to the ENT surgeon. Here we present a case of epistaxis arising from the sphenopalatine artery in a patient who had previously had the ipsilateral external carotid artery ligated due to previous epistaxis. On investigation the epistaxis was determined to arise from an anastamosis with the contralateral sphenopalatine artery. The anatomy was demonstrated with angiography and the epistaxis treated using microcatheter embolization. Anatomical variation can be a cause for failure of ligation as a permanent treatment for epistaxis. Embolization is used less frequently for epistaxis control due to concerns about the risks involved, but it can be a valuable treatment option in intractable epistaxis following a failure of arterial ligation

    Endoscopic Dacryocystorhinostomy: Creation of a Large Marsupialized Lacrimal Sac

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    This retrospective study describes and evaluates the effectiveness of a modified technique of conventional endoscopic dacryocystorhinostomy (DCR) that minimizes the obstruction of a neo-ostium by creating an enlarged marsupialized lacrimal sac using mucosal flaps. Forty-two patients who had undergone 46 endoscopic DCR at a tertiary medical center, from 2002 to 2004, for correction of lacrimal system obstruction were investigated. The surgical technique involves elevation of a nasal mucosal flap, full sac exposure using a power drill, and shaping of the mucosal flap to cover denuded bone and juxtapose exposed sac mucosa. Postoperative symptoms and endoscopic findings of the neo-ostium were evaluated. Mean duration of follow-up was 5.9 months. An eighty-three percent primary success rate was observed, without any serious complications. Obstruction of the neo-ostium with granulation tissue was observed in eight cases, among which six underwent revision with success in all cases. Overall, 44 (96%) of 46 cases experienced surgical successes. Endoscopic DCR, a procedure in which a large marsupialized lacrimal sac is created from mucosal flaps, yields a very satisfactory success rate with straightforward and highly successful revision available for those in whom the primary procedure yields a substandard result

    Job Life Cycle Management Libraries for CMS Workflow Management Projects

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    Scientific analysis and simulation requires the processing and generation of millions of data samples. These processing and generation tasks are often comprised of multiple smaller tasks divided over multiple (computing) sites. This paper discusses the Compact Muon Solenoid (CMS) workflow infrastructure, and specifically the Python based workflow library which is used for so called task lifecycle management. The CMS workflow infrastructure consists of three layers: high level specification of the various tasks based on input/output datasets, life cycle management of task instances derived from the high level specification and execution management. The workflow library is the result of a convergence of three CMS subprojects that respectively deal with scientific analysis, simulation and real time data aggregation from the experiment

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV