1,721,003 research outputs found
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
Towards Access Control for Machine Learning Embeddings
No full textIn this work, we explore the potential to make embeddings, which are becoming an integral part of machine-learning pipelines, shareable with the general public while providing self-contained access control. To this end, we apply attribute-based encryption and discuss a potential application for supply chain management
Demystifying and adjusting the promises of blockchain-based data management in the permissionless setting
No full textThe digital currency Bitcoin introduced the blockchain as a data structure that allows its users to establish consensus about who owns which coins in a decentralized manner. Since then, blockchain technology has evolved and now enables distrusting parties to engage in online interactions without the need for a trusted intermediary by immutably recording general events in transactions. This interaction model sparked a tremendous interest in blockchain technology, its potential, and applications.However, the identification of multiple shortcomings has since dampened this initial spirit of optimism. These shortcomings are especially apparent for permissionless blockchains, such as Bitcoin, which openly encourage participation by anybody. For instance, Bitcoin has to secure its blockchain against malicious actors by relying on energy-intensive computations, which further leads to scalability issues as only few payments can be accepted at a time. While prior work has extensively studied such technical challenges, it neglected the influence of the data stored on the blockchain so far. Yet, this influence becomes undeniable: On the one hand, unknown actors can irrevocably append new data without a designated removal process. On the other hand, the operation of a blockchain system depends on a massive replication of its full and growing history. Hence, the impact of blockchain-recorded data requires thorough investigation to ensure the security and longevity of blockchain systems.In this dissertation, we thus take a data-driven perspective to assess and improve the applicability of permissionless blockchains as building blocks for decentralized data management systems. We identify two core challenges of blockchain-based data management, i.e., the need for moderating what data is recorded and the need for alleviating the continually growing storage requirements stemming from the append-only nature of blockchains. Furthermore, we assess the potential of blockchains to enable additional applications by seizing their characteristic properties. We address these challenges on a technical level via the following contributions.As our first contribution, we systematically analyze the phenomenon of blockchain content insertion on a conceptual, technical, and empirical level. Our analysis reveals that content insertion is a common practice and offers benefits for higher-level applications, but inserting illicit content can potentially create devastating consequences for the participants. As our second contribution, we explore means to mitigate these consequences, both before and after the fact, by proposing strategies to prevent the insertion of unwanted content as well as a redactable blockchain that enables a swift and transparent removal of content. Our third contribution addresses the challenge of growing blockchain sizes by defining a gradually deployable block-pruning scheme that is retrofittable to Bitcoin and enables users to retroactively forget obsolete data and thereby reduce their storage requirements. Finally, our fourth contribution shows that permissionless blockchains still hold untapped potential for fueling novel applications despite their limitations; namely, we demonstrate how Bitcoin can help securely bootstrapping decentralized anonymity services. Overall, we shed new light on the potential impact of the data persisted on blockchains. Our analyses and technical contributions therefore widen the scope for resilient and durable blockchain designs for data management tasks
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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Get PDFWe 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
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