1,720,980 research outputs found
A Multilevel Scheduler for Batch Jobs on Grids
No full textThis paper proposes a two-level scheduler for dynamically scheduling a continuous stream of sequential and multi-threaded batch jobs on grids, made up of interconnected clusters of heterogeneous single-processor and/or symmetric multiprocessor machines. The scheduler aims to schedule arriving jobs respecting their computational and deadline requirements, and optimizing the hardware and software resource usage. At the top of the hierarchy a lightweight meta-scheduler (MS) classifies incoming jobs according to their requirements, and schedules them among the underlying resources balancing the workload. At cluster level a Flexible Backfilling algorithm carries out the job machine associations by exploiting dynamic information about the environment. Scheduling decisions at both levels are based on job priorities computed by using different sets of heuristics. The different proposals have been compared through simulations. Performance figures show the feasibility of our approach
A Priority-Based Multilevel Scheduler for Dynamic Scheduling a Continuous Stream of Batch Jobs in Grids
No full textDDT: A Distributed Data Structure for the Support of P2P Range Query
No full textThis paper defines and evaluates a hierarchical distributed data structure, distributed digest trie, supporting range queries in P2P systems. Providing efficient support for these queries is currently a challenging research issue in the P2P field, as classical approaches based on distributed hash tables (DHT) are often not suitable for this kind of queries, due to the loss of locality introduced by the hashing function. Distributed digest trie exploits the DHT only to define a uniform assignment of logical identifiers to peers while each key is managed by the peer publishing it. Each peer is paired with the leaf of the trie corresponding to its logical identifier. An internal node of the trie stores a digest summarizing the keys published by the peers paired with the leaves of the tree rooted at that node. A proper mapping function is defined to map the internal nodes of the trie to the peers. The digests stored at the internal nodes are exploited to guide the search process for the resolution of the range query. Different aggregation techniques are proposed. A set of experimental results compare these techniques, evaluate the cost of dynamic updates of the data structure and the network traffic generated by the method
A two level scheduler to dynamically a strean of batch jobs in large scale grids
No full textThis paper describes the study conducted to design and evaluate a two-level on-line scheduler to dynamically schedule a stream of sequential and multi-threaded batch jobs on large scale grids, made up of interconnected clusters of heterogeneous machines. The scheduler aims to schedule arriving jobs respecting their computational and deadline requirements, and optimizing the utilization of hardware resources as well as software resources
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Service and Resource Discovery Supports over P2P Overlays
No full textWe describe the main architecture and the
design principles of the Service/Resource Discovery System
(SRDS), a component of the XtreemOS Operating System.
XtreemOS is a Linux extension that enables management and exploitation as single platform of computational
resources provided by federated Virtual Organizations.
The SRDS provides scalable and fault-tolerant directory
services supporting many of the platform functionalities,
ranging from dynamic resource location and job control
to system and application-oriented directory services.
The key challenge of the SRDS design is to provide
the common metaphor of the directory service, meeting
the scalability requirements of a Grid-aware Operating
system, and at the same time enjoy extendability and
configurability, especially with respect to the quality of
service provided. The SRDS design combines different
peer to peer structured overlay networks, exploiting their
peculiar strengths. We describe the implementation and
our design of the namespace abstraction as implemented
on top of multiple overlay networks. Finally, we show test
results of the SRDS on top of a subset of the Grid5000
platform
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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