3,691 research outputs found

    PanDA Workload Management System Meta-data Segmentation

    Get PDF
    AbstractThe PanDA (Production and Distributed Analysis) workload management system (WMS) was developed to meet the scale and complexity of LHC distributed computing for the ATLAS experiment. PanDA currently distributes jobs among more than 100,000 cores at well over 120 Grid sites, supercomputing centers, commercial and academic clouds. ATLAS physicists submit more than 1.5M data processing, simulation and analysis PanDA jobs per day, and the system keeps all meta-information about job submissions and execution events in Oracle RDBMS. The above information is used for monitoring and accounting purposes. One of the most challenging monitoring issues is tracking errors that has occurred during the execution of the jobs. Current meta-data storage technology doesn‚Äôt support inner tools for data aggregation, needed to build error summary tables, charts and graphs. Delegating these tasks to the monitor slows down the execution of requests.We will describe a project aimed at optimizing interaction between PanDA front-end and back-end, by meta-data storage segmentation into two parts ‚Äď operational and archived. Active meta-data are remained in Oracle database (operational part), due to the high requirements for data integrity. Historical (read-only) meta-data used for the system analysis and accounting are exported to NoSQL storage (archived part). New data model based on usage of Cassandra as the NoSQL backend has been designed as a set of query-specific data structures. This allowed to remove most of data preparation workload from PanDA Monitor and improve its scalability and performance. Segmentation and synchronization between operational and archived parts of jobs meta-data is provided by a Hybrid Meta-data Storage Framework (HMSF). PanDA monitor was partly adopted to interact with HMSF. The operational data queries are forwarded to the primary SQL-based repository and the analytic data requests are processed by NoSQL database. The results of performance and scalability tests of HMSF-adopted part of PanDA Monitor shows that presented method of optimization, in conjunction with a properly configured NoSQL database and reasonable data model, provides performance improvements and scalability

    Plasmon channels in the electronic relaxation of diamond under high-order harmonics femtosecond irradiation

    Get PDF
    We used high order harmonics of a femtosecond titanium-doped sapphire system (pulse duration 25 fs) to realise Ultraviolet Photoelectron Spectroscopy (UPS) measurements on diamond. The UPS spectra were measured for harmonics in the range 13 to 27. We also made ab initio calculations of the electronic lifetime of conduction electrons in the energy range produced in the UPS experiment. Such calculations show that the lifetime suddenly diminishes when the conduction electron energy reaches the plasmon energy, whereas the UPS spectra show evidence in this range of a strong relaxation mechanism with an increased production of low energy secondary electrons. We propose that in this case the electronic relaxation proceeds in two steps : excitation of a plasmon by the high energy electron, the latter decaying into individual electron-hole pairs, as in the case of metals. This process is observed for the first time in an insulator and, on account of its high efficiency, should be introduced in the models of laser breakdown under high intensity

    The Tajik Civil War and Russia’s Islamist moment

    Get PDF
    Published online: 10 November 2022Contra the often-held assumption that the Islamist danger has been at the forefront of Moscow‚Äôs security agenda since the Soviet‚ÄďAfghan War, this article shows how different Russian decision-makers held different views of Islamism during the Tajik Civil War (1992‚Äď97). It argues that different relations to the Soviet past, especially to the Soviet‚ÄďAfghan War, explain the differences in assessing Islamism in Tajikistan between the security agencies and political elites. Unlike the reformers in the Kremlin, the legacy Soviet security elites and diplomats in Russia and the neo-communist leaders in Central Asia recalled the Islamist danger from Soviet times. They emphasized it to the Kremlin who came to embrace their view as the Tajik Civil War progressed and tensions rose in Chechnya

    In search of Islamic legitimacy : the USSR, the Afghan communists and the Muslim world

    Get PDF
    Published online: 02 October 2022During the Afghan War, the Mujahideen claimed that the Afghan communists were atheists who were subservient to Moscow and did not have the legitimacy to rule Afghanistan. The war became a contest for legitimacy in Afghanistan and internationally. The Soviets and the Afghan communists portrayed communist Afghanistan as Islamic and therefore legitimate in the international arena. The Soviets elaborated an information campaign emphasising Islam and strengthened Afghanistan’s contacts with Muslim countries to show that the Afghan communists were Muslims too. They hoped international recognition would reduce Muslim countries’ support to the Mujahideen and improve the Afghan communists’ acceptance at home

    Bringing the war home : the strategic logic of ‚ÄėNorth Caucasian terrorism‚Äô in Russia

    Get PDF
    Published online: 03 July 2020Terrorism connected to the North Caucasus has been pervasive in Russia between 1992 and 2018. Based on an original dataset, this article presents statistics on rates of terrorist attacks outside of the North Caucasus, their geography and targets, and the tactics used. It argues that terrorism by North Caucasian insurgents has long retained a strategic logic despite their conversion to radical Islamism. Accordingly, the end of North Caucasian terrorism was determined by the erosion of its strategic character as an increasingly vague ideological project replaced concrete political goals among the insurgents

    ‚ÄúCommunist Muslims‚ÄĚ : The USSR and the people's democratic party of Afghanistan's conversion to Islam, 1978‚Äď1988

    Get PDF
    Soviet leaders sent troops into Afghanistan in December 1979 to support a friendly Marxist-Leninist regime in its conflict against a popular insurgency and help it build a new society. When the Soviet troops withdrew nine years later, they left behind a state that had none of the nominal characteristics of a Soviet-type Communist country. During the war, the People's Democratic Party of Afghanistan had discarded Marxism-Leninism and turned to Islam. This article examines how, with Moscow's support, the Afghan Communists Islamicized their discourse and policies as they tried to gain support from the population and co-opt insurgent fighters

    The allure of Jihad : the de-territorialization of the war in the North Caucasus

    Get PDF
    Published online: 22 October 2020Insurgents in the North Caucasus switched from the al-Qaedaaffiliated Imarat Kavkaz to the Islamic State after 2014. Although this transition was partially the result of Imarat Kavkaz’s military defeat, it has also settled two decades of tension over ideology. It signalled the victory of Salafi-jihadism over a nationally rooted (radical) Islamism and led to a break between the insurgents and the Caucasian context. This de-territorialization of grievances for the war has in turn increased the threat of radical Islamist violence for Russia

    ATLAS Logical File Name and Directory Path Convention

    Get PDF
    The convention to form logical files entries in file's catalog used by ATLA

    ATLAS Distributed Data management Operations

    Get PDF
    ATLAS Distributed Data Management (DDM) service is developed for data transfer between ATLAS sites and for data cataloguing. The Data Management Software (SW) is based on DQ2 and end-users tools (aka dq2_get package). In this paper we address the issue of DDM day-by-day operation, DDM operations team organization, roles and responsibilities of Tier-1s and Tier-2s DDM coordinators
    • ‚Ķ