1,721,446 research outputs found
Growing Hierarchical Tree SOM: an Unsupervised Neural Network with Dynamic Topology
No full textIn this paper we introduce a tree structured self-organizing network, called the Growing Hierarchical Tree SOM (GHTSOM), that combines unsupervised learning with a dynamic topology for hierarchical classification of unlabelled data sets. The main feature of the proposed model is a SOM-like self-organizing process that allows the network to adapt the topology of each layer of the hierarchy to the characteristics of the training set. In particular the self-organization is obtained in two steps: the first one concerns the learning phase and is finalized with the creation of a tree of SOMs, while the second one is in regard to the clustering phase and provides the formation of classes for each level of the tree (hence self-organization not only for training but also for the creation of topological connections). As a result the network works without the need for user-defined parameters. Experimental results are proposed on both synthetic and real data sets. (c) 2006 Elsevier Ltd. All rights reserved
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
Digital Forensics in Vessel Transportation Systems
No full textLarge vessels are safety-critical systems where operations, performance and component availability are continuously monitored by means of multiple sensors producing large amount of data. Relevant information is preserved in Event Data Recorders that are fundamental for the reconstruction of scenarios related to serious malfunctions and incidents in technical and legal terms. By considering the state-of-the-art and two important naval accidents we evidence some issues related to the exploitation of recorded data in reconstructing the events timeline and the semantics of the scenarios. These studies motivate our proposal that aims to guarantee strong data integrity and availability of all information registered in Event Data Recorders. Our results are fundamental for the precise identification of the sequences of events and for the correct attribution of human and/or machine responsibilities
Adversarial fingerprinting of cyber attacks based on stateful honeypots
No full textThe cyber defenses of Critical Infrastructures require early detection of new threats and attacks. This includes defensive systems that are able to learn from novel attacks and to detect 0-day vulnerabilities as early as possible. Honeypots are not defensive systems based on prevention, but they still represent an effective way to gather information about attacks from the source. Nevertheless, most existing solutions operate in a stateless way. As a consequence, they are easily identified by expert attackers, and they are unable to track progress of individual attacks in large applications. We propose a novel approach that enables a so called stateful honeypot. The idea comes from the observation that a typical cyber attack to a Critical Infrastructure is carried out through multiple attempts and intrusions. Hence the main goal is to fingerprint each attacker by observing and registering his adopted methods, tools and actions. Once identified, the adversary is redirected to his specific environment that preserves the history of his previous operations including the installation of rootkits or backdoors. The proposed solution paves the way to a more effective generation of honeypots that are necessary to face the augmented complexity of cyber attacks
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
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