1,720,978 research outputs found
Precise Worst-case Blocking Time of Tasks under Priority Inheritance Protocol
Full text linkThe problem of precisely computing the worst-case blocking time that tasks may experience is one of the fundamental issues of schedulability analysis of real-time applications. While exact methods have been proposed for more sophisticated protocols, the problem is indeed complex in case of the Priority Inheritance Protocol, even restricting the attention to uniprocessor systems, non-nested resource accesses, and non-self-suspending tasks. Besides a very simple method leading in general to loose upper bounds, only one algorithm of exponential complexity has been so far reported in literature to tighten such bounds.
In this work, we describe a novel approach which, leveraging an operational research technique for modeling the problem, computes the same tight bounds in polynomial time. We then discuss the scenarios in which, assuming no conditional statements in the tasks’ code, the computed bounds derive from an actually impossible blocking chain, and we refine the initial model to more precisely compute the worst-case blocking times for any task set in any possible operating condition
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
Progetto e realizzazione di un modello di Hmi dinamicamente riconfigurabile per macchine automatiche multidosaggio
Full text linkObiettivo della tesi è stato quello di analizzare, progettare e realizzare un modello di interfaccia uomo-macchina per macchine automatiche multidosaggio che fosse dinamicamente riconfigurabile alla variazione della configurazione operativa
Progettazione e sviluppo del software di controllo di un sistema di trascinamento di matasse di filo guainato
Full text linkL’obiettivo della tesi è di implementare un’architettura software per controllare in modo automatico il posizionamento di una matassa di filo guinato e coordinare il funzionamento delle macchine dell’impianto con l’obiettivo di realizzare a partire da un avvolto di filo la legatura dello stesso.
Il progetto oltre a realizzare la logica di controllo del sistema di trasci-namento della matassa, si estende nella simulazione e visualizzazione dell’intero sistema tramite interfaccia grafica integrata nell’ambiente di sviluppo utilizzato. Inoltre, è stato gestito il comportamento del siste-ma, simulando le possibili anomalie che possono verificarsi durante il funzionamento dei dispositivi dell’impianto e durante l’ARRESTO DI EMERGENZA.
È stato presentato il modello CIM analizzando la funzione volta dai vari livelli e i relativi tipi di controllo, ponendo at-tenzione ai livelli e ai controlli d’interesse che sono stati trattati nell’elaborato.
viene mostrata una panoramica dell’ambiente di sviluppo del software per sistemi di automazione utilizzato, Codesys, presentando le applicazioni in cui viene utilizzato, il modello software standardizzato dalla norma IEC, gli oggetti del ‘browser di progetto’ necessari per im-plementare un’applicazione per PLC, i programmi principali che realiz-zano un’applicazione di controllo e l’interfaccia grafica resa disponibile dal tool di sviluppo.
Si presentano le caratteristiche dei dispositivi che compongono il sistema di trascinamento; descrive il funzionamento nominale e in ca-so di ARRESTO DI EMERGENZA o di FAULTS dei dispositivo, uti-lizzando sia il modello grafico, ‘automi a stati finiti’, che la relativa tra-duzione nel codice eseguibile corrispondente, scritto in linguaggio ‘testo strutturato’
Modelli ILP per la determinazione delle prestazioni conseguibili con il protocollo "Priority Inheritance" in applicazioni multitasking hard real-time
Full text linkRegole ed esempi pratici sulla costruzione di Modelli di Programmazione Lineare Intera per la rappresentazione di task periodici di Applicazioni Real-Time e delle loro interazioni bloccanti; utili per la determinazione del "massimo tempo di blocco" che i processi possono subire, nell'ipotesi: che siano schedulati con strategia "Rate Monotonic Priority Order"; che la politica di gestione degli accessi alle risorse condivise sia quella definita dal protocollo "Priority Inheritance"
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