1,720,962 research outputs found
Modern Data Storage Architectures for Managing Big Data: The Role of Semantically Enrichment Mechanisms in Data Management and Security
No full textΑυτή η διδακτορική διατριβή κινείται στο ευρύτερο πεδίο της Έξυπνης Επεξεργασίας Δεδομένων (Smart Data Processing - SDP) και των Συστημάτων Βαθέων Ενοράσεων (Systems of Deep Insights - SDI), εστιάζοντας στην αποθήκευση και διαχείριση Μεγάλων Δεδομένων (Big Data), αντιμετωπίζοντας σημαντικές προκλήσεις όπως η βελτιστοποίηση της πρόσβασης, της ασφάλειας και της ανάκτησης των δεδομένων. Εξετάζει σύγχρονες προσεγγίσεις για την αποδοτική διαχείριση πηγών δεδομένων, την οργάνωση και αποθήκευσή τους, εξασφαλίζοντας απρόσκοπτη πρόσβαση και ανάκτηση, ενώ ταυτόχρονα διαχειρίζεται ζητήματα που σχετίζονται με την ακεραιότητα των δεδομένων, την ιδιωτικότητα και τον έλεγχο πρόσβασης. Μια βασική συνεισφορά της έρευνας αυτής είναι η ανάπτυξη ενός εννοιολογικά εμπλουτισμένου πλαισίου Data Lake, το οποίο ενισχύει τη δομή, την προσβασιμότητα και τη διακυβέρνηση των δεδομένων μέσω της αξιοποίησης εννοιολογικών προτύπων δεδομένων καθοδηγούμενων από μεταδεδομένα (Semantic Data Blueprints - SDB), υποστηρίζοντας παράλληλα και την εξόρυξη διαδικασιών (process mining). Τα εμπειρικά ευρήματα δείχνουν ότι οι αρχιτεκτονικές Data Mesh υπερτερούν σημαντικά των παραδοσιακών Data Lakes, προσφέροντας αυξημένη επεκτασιμότητα, ευελιξία και ευκινησία στη λήψη αποφάσεων. Η διατριβή αποδεικνύει ότι η μετάβαση από κεντρικοποιημένα Data Lakes σε αποκεντρωμένες, εννοιολογικά εμπλουτισμένες αρχιτεκτονικές Data Mesh επιτρέπει την ενίσχυση της ανακαλυψιμότητας των δεδομένων, της άντλησης πληροφοριών σε πραγματικό χρόνο και της ασφαλούς διαλειτουργικότητας μεταξύ οργανισμών. Η εφαρμογή των παραπάνω εννοιών σε ένα περιβάλλον έξυπνης παραγωγής καταδεικνύει πώς τα Data Mesh που καθοδηγούνται από μεταδεδομένα μπορούν να βελτιώσουν την επιχειρησιακή αποδοτικότητα, την ιχνηλασιμότητα των δεδομένων και να υποστηρίξουν αποκεντρωμένους μηχανισμούς ελέγχου πρόσβασης. Η ενσωμάτωση τεχνολογίας Blockchain και Μη Ανταλλάξιμων Διακριτικών (Non-Fungible Tokens - NFTs) ενισχύει περαιτέρω την ιδιοκτησία, την ακεραιότητα και την ασφαλή διαχείριση πρόσβασης στα Data Lakes και τα Data Meshes. Μέσα από πειραματική αξιολόγηση με τη χρήση πραγματικών βιομηχανικών δεδομένων, η έρευνα αναδεικνύει την αποτελεσματικότητα του προτεινόμενου πλαισίου στη βελτιστοποίηση των ροών δεδομένων, στη μείωση καθυστερήσεων επεξεργασίας και στην ενίσχυση της ασφάλειας. Η παρούσα διατριβή παρέχει πολύτιμες μεθοδολογίες για επιχειρήσεις που επιδιώκουν να αξιοποιήσουν τη δύναμη των Μεγάλων Δεδομένων, προάγοντας ένα πιο έξυπνο, ασφαλές και προσαρμοστικό πρότυπο διαχείρισης δεδομένων.This PhD thesis moves in the broader area of Smart Data Processing (SDP) and Systems of Deep Insights (SDI) and focuses on Big Data storage and management, addressing significant challenges such as optimizing data access, security, and retrieval. It explores current approaches for efficiently managing data sources, their organization, and storage for seamless access and retrieval while addressing challenges related to data integrity, privacy, and access control. A key contribution of this research is the development of a semantically enriched Data Lake framework, which enhances data structuring, accessibility, and governance by leveraging metadata-driven semantic data blueprints (SDB) supporting also process mining. Empirical findings demonstrate that Data Mesh architectures significantly outperform traditional Data Lakes, offering improved scalability, flexibility, and decision-making agility. The thesis demonstrates how transitioning from centralized Data Lakes to decentralized, semantically enriched Data Meshes enables enhanced data discoverability, real-time insights, and secure cross-organizational collaboration. The application of the aforementioned concepts in a smart manufacturing environment showcases how metadata-driven Data Meshes streamline operational efficiency, improve data traceability, and facilitate decentralized access control mechanisms. The integration of Blockchain technology and Non-Fungible Tokens (NFTs) further strengthens data ownership, integrity, and secures access management in Data Lakes and Data Meshes. Through experimental evaluation using real-world industrial data, research conducted highlights the effectiveness of the proposed framework in optimizing data workflows, reducing processing delays and enhancing security. This research provides valuable methodologies for enterprises seeking to harness the power of Big Data, fostering a more intelligent, secure, and adaptive data management paradigm.Dr. Andreas S. Andreou, Professor
Dr. Herodotos Herodotou, Associate Professor
Dr. Willem-Jan van den Heuvel, ProfessorComplete
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
Exploiting Metadata Semantics in Data Lakes Using Blueprints
No full textSmart processing of Big Data has been recently emerged as a field that provides quite a few challenges related to how multiple heterogeneous data sources that produce massive amounts of structured, semi-structured and unstructured data may be handled. One solution to this problem is manage this fusion of disparate data sources through Data Lakes. The latter, though, suffers from the lack of a disciplined approach to collect, store and retrieve data to support predictive and prescriptive analytics. This chapter tackles this challenge by introducing a novel standardization framework for managing data in Data Lakes that combines mainly the 5Vs Big Data characteristics and blueprint ontologies. It organizes a Data Lake using a ponds architecture and describes a metadata semantic enrichment mechanism that enables fast storing to and efficient retrieval. The mechanism supports Visual Querying and offers increased security via Blockchain and Non-Fungible Tokens. The proposed approach is compared against other known metadata systems utilizing a set of functional properties with very encouraging results
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
A Data Lake Metadata Enrichment Mechanism via Semantic Blueprints
No full textOne of the greatest challenges in Smart Big Data Processing nowadays revolves around handling multiple heterogeneous data sources that produce massive amounts of structured, semi-structured and unstructured data through Data Lakes. The latter requires a disciplined approach to collect, store and retrieve/analyse data to enable efficient predictive and prescriptive modelling, as well as the development of other advanced analytics applications on top of it. The present paper addresses this highly complex problem and proposes a novel standardization framework that combines mainly the 5Vs Big Data characteristics, blueprint ontologies and Data Lakes with ponds architecture, to offer a metadata semantic enrichment mechanism that enables fast storing to and efficient retrieval from a Data Lake. The proposed mechanism is compared qualitatively against existing metadata systems using a set of functional characteristics or properties, with the results indicating that it is indeed a promising approach
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
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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