1,720,965 research outputs found
PHAST Library - A Productive Solution to Program Heterogeneity
Full text linkOggigiorno, le architetture parallele sono ovunque: computer desktop, dispositivi mobile, workstation ad alte prestazioni e server sono solo alcuni esempi. Oltre ai classici multi-core, anche GPU, FPGA, TPU e altri dispositivi vengono utilizzati in un ampio spettro di applicazioni. In questa era post-PC, i programmatori devono necessariamente sfruttare l'eterogeneità per utilizzare pienamente l'hardware e raggiungere prestazioni senza precedenti.
Scrivere codice eterogeneo può essere difficile: ogni dispositivo può avere i suoi linguaggi, i suoi framework e i suoi stili di programmazione. Pertanto, per essere produttivi, bisognerebbe preferire degli approcci eterogenei che consentano la scrittura di codice una volta sola. Questi approcci devono fornire come minimo la portabilità del codice tra dispositivi, ma anche la portabilità delle prestazioni, così da ridurre la necessità di programmare e ottimizzare diverse architetture in maniera specifica. Nonostante l'ampia diffusione di dispositivi eterogenei, tali framework sono ancora di là da venire.
Questa tesi di Dottorato presenta il mio contributo alla programmazione parallela ed eterogenea. In una prima parte viene discusso approfonditamente lo stato dell'arte dell'ambito di appartenenza. In seguito viene presentato un framework che mira a porsi come punto di riferimento, tentando di conciliare i punti forti delle diverse soluzioni concorrenti, limitandone le debolezze.
Questo framework, dal nome PHAST Library, è una libreria di programmazione single-source in C++ moderno che fornisce produttività e portabilità di codice e prestazioni tra dispositivi paralleli. In questo lavoro si discutono le caratteristiche in maniera approfondita e se ne valuta il valore tramite confronto con altri framework eterogenei ad alto livello di astrazione, sia da un punto di vista prestazionale che di produttività. Dal confronto, che annovera esempi semplici e applicazioni reali, emerge che il framework è maturo. Inoltre, PHAST Library rappresenta un miglioramento misurabile dello stato dell'arte e perciò può essere utilizzato per lo sviluppo di applicazioni parallele ed eterogenee in maniera produttiva e portabile. La tesi si conclude con la discussione delle sue possibili evoluzioni.Nowadays, parallel architectures are everywhere: desktop computers, mobile devices, high-performance workstations, and servers are just a few examples. Not only multi-core microprocessors, but also GPUs, FPGAs, TPUs, and other computing devices are widely used in a broad range of applications. Programmers willing to code in this post-PC era need to take advantage of heterogeneity in order to fully utilize these devices and reach unprecedented performance.
Programming heterogeneity can be difficult: each device can have its own languages, frameworks, and coding styles. Heterogeneous approaches that let programmers code once must be preferred for productivity reasons. They must provide portability as a minimum requirement, but also performance portability to reduce the need of device-specific coding and tuning. Despite the wide diffusion of heterogeneous computing devices, frameworks with these facilities are yet to come.
This Ph.D. thesis presents my contribution to parallel and heterogeneous programming. After presenting an in-depth study of the state-of-the-art programming approaches for heterogeneous devices, it presents a programming framework that aims at embodying their strengths while limiting their weaknesses.
This framework, called PHAST Library, is a modern C++ single-source programming library that provides near-native performance, productivity, portability, and performance portability across parallel computing devices. This thesis discusses it in-depth and evaluates it against other productive heterogeneous frameworks from both performance and productivity points of view. The comparison is done in the case of various toy and real-world applications, which shows that the framework is mature. It also improves the state-of-the-art in a measurable way, and thus its use can help programmers to write high-level, high-performance parallel heterogeneous code. In conclusion, a possible evolution of the framework is presented
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
Flexible task‐DAG management in PHAST library: Data‐parallel tasks and orchestration support for heterogeneous systems
No full textDispelling 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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