1,721,018 research outputs found
Solving Linear Systems on High Performance Hardware with Resilience to Multiple Hard Faults
Full text linkAs large-scale linear equation systems are pervasive in many scientific fields, great efforts have been done over the last decade in realizing efficient techniques to solve such systems, possibly relying on High Performance Computing (HPC) infrastructures to boost the performance. In this framework, the ever-growing scale of supercomputers inevitably increases the frequency of faults, making it a crucial issue of HPC application development.A previous study [1] investigated the possibility to enhance the Inhibition Method (IMe) -a linear systems solver for dense unstructured matrices-with fault tolerance to single hard errors, i.e. failures causing one computing processor to stop.This article extends [1] by proposing an efficient technique to obtain fault tolerance to multiple hard errors, which may occur concurrently on different processors belonging to the same or different machines. An improved parallel implementation is also proposed, which is particularly suitable for HPC environments and moves towards the direction of a complete decentralization. The theoretical analysis suggests that the technique (which does not require check pointing, nor rollback) is able to provide fault tolerance to multiple faults at the price of a small overhead and a limited number of additional processors to store the checksums. Experimental results on a HPC architecture validate the theoretical study, showing promising performance improvements w.r.t. a popular fault-tolerant solving technique
Reporter: a straightforward web tool for collaborative document production
Full text linkLa produzione di report periodici sulle attività eseguite in grandi progetti che coinvolgono gruppi geograficamente distribuiti è solitamente un compito che richiede una grande quantità di tempo e, nonostante le moderne tecnologie, viene ancora frequentemente eseguito manualmente facendo un collage dei contributi necessari. Nonostante l’espansione delle soluzioni web in aree una volta dominate da applicazioni desktop abbia reso disponibili alcuni strumenti collaborativi online, è ancora difficile trovare semplici strumenti collaborativi web studiati per supportare la predisposizione di documenti comuni tra persone appartenenti a grandi comunità. È stato quindi sviluppato Reporter al fine di fornire un supporto alla produzione di report periodici nell’ambito del programma europeo JPNM (Joint Program on Nuclear Materials). Tale strumento, grazie alla sua flessibilità, si presta ad essere utilizzato anche per predisporre altri tipi di documenti in cui è richiesta la composizione di contributi provenienti da più persone.Producing periodic reports on activities carried out in large projects that involve teams geographically distributed is usually a really time consuming task that, despite modern technologies, often is still performed making a manual collage of all needed contributions. Even though web based solutions expansion into areas once dominated by desktop applications offers some online collaboration tools, it is still difficult to find simple to use collaborative web tools designed to support preparation of common documents among people belonging to large communities. In order to support periodic progress reports production in the frame of the European Joint Program on Nuclear Materials, it has thus developed Reporter which, thanks to its flexibility, can also be used to prepare other types of documents where a composition of contributions coming from several people is needed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Fractional derivatives, memory kernels and solution of a free electron laser volterra type equation
Full text linkThe high gain free electron laser (FEL) equation is a Volterra type integro-differential equation amenable for analytical solutions in a limited number of cases. In this note, a novel technique, based on an expansion employing a family of two variable Hermite polynomials, is shown to provide straightforward analytical solutions for cases hardly solvable with conventional means. The possibility of extending the method by the use of expansion using different polynomials (two variable Legendre like) expansion is also discussed
I tumori in Provincia di Modena nel biennio 1998-1999.
No full textMonografi a sui dati di incidenza e sopravvivenza delle neoplasie nella provincia di Moden
- …
