In order to ensure an optimal performance of the LHCb Distributed Computing, based on LHCbDIRAC, it is necessary to be able to inspect the behavior over time of many components: firstly the agents ...and services on which the infrastructure is built, but also all the computing tasks and data transfers that are managed by this infrastructure. This consists of recording and then analyzing time series of a large number of observables, for which the usage of SQL relational databases is far from optimal. Therefore within DIRAC we have been studying novel possibilities based on NoSQL databases (ElasticSearch, OpenTSDB and InfluxDB) as a result of this study we developed a new monitoring system based on ElasticSearch. It has been deployed on the LHCb Distributed Computing infrastructure for which it collects data from all the components (agents, services, jobs) and allows creating reports through Kibana and a web user interface, which is based on the DIRAC web framework. In this paper we describe this new implementation of the DIRAC monitoring system. We give details on the ElasticSearch implementation within the DIRAC general framework, as well as an overview of the advantages of the pipeline aggregation used for creating a dynamic bucketing of the time series. We present the advantages of using the ElasticSearch DSL high-level library for creating and running queries. Finally we shall present the performances of that system.
The LHCb collaboration is one of the four major experiments at the Large Hadron Collider at CERN. Many petabytes of data are produced by the detectors and Monte-Carlo simulations. The LHCb Grid ...interware LHCbDIRAC 1 is used to make data available to all collaboration members around the world. The data is replicated to the Grid sites in different locations. However the Grid disk storage is limited and does not allow keeping replicas of each file at all sites. Thus it is essential to optimize number of replicas to achieve a better Grid performance. In this study, we present a new approach of data replication and distribution strategy based on data popularity prediction. The popularity is performed based on the data access history and metadata, and uses machine learning techniques and time series analysis methods.
The LHCb experiment relies on the Online system, which includes a very large and heterogeneous computing cluster. Ensuring the proper behavior of the different tasks running on the more than 2000 ...servers represents a huge workload for the small operator team and is a 24/7 task. At CHEP 2012, we presented a prototype of a framework that we designed in order to support the experts. The main objective is to provide them with steadily improving diagnosis and recovery solutions in case of misbehavior of a service, without having to modify the original applications. Our framework is based on adapted principles of the Autonomic Computing model, on Reinforcement Learning algorithms, as well as innovative concepts such as Shared Experience. While the submission at CHEP 2012 showed the validity of our prototype on simulations, we here present an implementation with improved algorithms and manipulation tools, and report on the experience gained with running it in the LHCb Online system.
The LHCb online system relies on a large and heterogeneous IT infrastructure made from thousands of servers on which many different applications are running. They run a great variety of tasks: ...critical ones such as data taking and secondary ones like web servers. The administration of such a system and making sure it is working properly represents a very important workload for the small expert-operator team. Research has been performed to try to automatize (some) system administration tasks, starting in 2001 when IBM defined the so-called “self objectives” supposed to lead to “autonomic computing”. In this context, we present a framework that makes use of artificial intelligence and machine learning to monitor and diagnose at a low level and in a non intrusive way Linux-based systems and their interaction with software. Moreover, the multi agent approach we use, coupled with an “object oriented paradigm” architecture should increase our learning speed a lot and highlight relations between problems.
The LHCb Data Acquisition during LHC Run 1 Alessio, F; Brarda, L; Bonaccorsi, E ...
Journal of physics. Conference series,
01/2014, Letnik:
513, Številka:
1
Journal Article
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The LHCb Data Acquisition system reads data from over 300 read-out boards and distributes them to more than 1500 event-filter servers. It uses a simple push-protocol over Gigabit Ethernet. After ...filtering, the data is consolidated into files for permanent storage using a SAN-based storage system. Since the beginning of data-taking many lessons have been learned and the reliability and robustness of the system has been greatly improved. We report on these changes and improvements, their motivation and how we intend to develop the system for Run 2. We also will report on how we try to optimise the usage of CPU resources during the running of the LHC ("deferred triggering") and the implications on the data acquisition.
ABSTRACT The co-planarity of solar system planets led Kant to suggest that they formed from an accretion disk, and the discovery of hundreds of such disks around young stars as well as hundreds of ...co-planar planetary systems by the Kepler satellite demonstrate that this formation mechanism is extremely widespread. Many moons in the solar system, such as the Galilean moons of Jupiter, also formed out of the accretion disks that coalesced into the giant planets. Here we report the discovery of an intermediate system, OGLE-2013-BLG-0723LB/Bb, composed of a Venus-mass planet orbiting a brown dwarf, which may be viewed either as a scaled-down version of a planet plus a star or as a scaled-up version of a moon plus a planet orbiting a star. The latter analogy can be further extended since they orbit in the potential of a larger, stellar body. For ice-rock companions formed in the outer parts of accretion disks, like Uranus and Callisto, the scaled masses and separations of the three types of systems are similar, leading us to suggest that the formation processes of companions within accretion disks around stars, brown dwarfs, and planets are similar.
ABSTRACT We present a combined analysis of the observations of the gravitational microlensing event OGLE-2015-BLG-0479 taken both from the ground and by the Spitzer Space Telescope. The light curves ...seen from the ground and from space exhibit a time offset of ∼13 days between the caustic spikes, indicating that the relative lens-source positions seen from the two places are displaced by parallax effects. From modeling the light curves, we measure the space-based microlens parallax. Combined with the angular Einstein radius measured by analyzing the caustic crossings, we determine the mass and distance of the lens. We find that the lens is a binary composed of two G-type stars with masses of ∼1.0 M and ∼0.9 M located at a distance of ∼3 kpc. In addition, we are able to constrain the complete orbital parameters of the lens thanks to the precise measurement of the microlens parallax derived from the joint analysis. In contrast to the binary event OGLE-2014-BLG-1050, which was also observed by Spitzer, we find that the interpretation of OGLE-2015-BLG-0479 does not suffer from the degeneracy between ( , ) and ( , ) solutions, confirming that the four-fold parallax degeneracy in single-lens events collapses into the two-fold degeneracy for the general case of binary-lens events. The location of the blend in the color-magnitude diagram is consistent with the lens properties, suggesting that the blend is the lens itself. The blend is bright enough for spectroscopy and thus this possibility can be checked from future follow-up observations.
Evaluation of the pharmacokinetic behavior of gadobenate dimeglumine, a new multipurpose parenteral contrast agent for magnetic resonance imaging.
The pharmacokinetics were evaluated in rats, ...rabbits, dogs and monkeys after intravenous injections of non-labelled gadobenate dimeglumine and, for biodistribution studies, 153Gd-labelled gadobenate dimeglumine. Assays were performed by high performance liquid chromatography, X-ray fluorescence and gamma spectrometry. The binding of gadobenate ion to animal and human serum albumin was studied by equilibrium dialysis.
After intravenous injection gadobenate dimeglumine distributes into plasma and extracellular fluid as well as into the intrahepatocytic space. Gadobenate ion is cleared from plasma by renal and biliary excretion. It does not accumulate in specific tissues, except temporarily in tissues related to its elimination. Gadobenate ion is not metabolized. Its binding to plasma proteins is too weak to be detected by equilibrium dialysis.
Gadobenate dimeglumine combines the properties of an extracellular-fluid agent with those of a hepatobiliary agent. Its complete elimination and biological stability satisfy the requirements for its safe use in humans.
This article examines group therapy with children and adolescents impacted by the September 11 terrorist attacks on the World Trade Center, with a focus on the role of metaphor, enactment, and the ...creative arts therapies in trauma treatment. Attention is given to the importance of fantasies, family structure, and culture in determining how the child constructs and processes the events. Examples are derived from ongoing, trauma-focused groups with traumatically bereaved children who lost parents, as well as from ongoing drama therapy groups in which traumatic themes emerged.
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