1,720,973 research outputs found
Improving the dependability of distributed surveillance systems using diverse redundant detectors
No full textSensor networks nowadays employed in critical monitoring and surveillance applications represent a relevant case of complex information infrastructures whose dependability needs to be carefully assessed. Detection models based on Event Trees provide a simple and effective mean to correlate events in Physical Security Information Management (PSIM) systems. However, as a deterministic modeling approach, Event Trees are not able to address uncertainties in practical applications, like: 1) imperfect threat modelling; 2) sensor false alarms. Regarding point (1), it is quite obvious that real-world threat scenarios can be very variable and it is nearly impossible to consider all the possible combinations of events characterizing a threat. Point (2) addresses the possibility of missed detections due to sensor faults and the positive/nuisance false alarms that any real sensor can generate. In this chapter we describe two techniques that can be adopted to deal with those uncertainties. The first technique is based on Event Tree heuristic distance metrics. It allows to generate warnings whenever a threat scenario is detected and it is similar to the ones in the knowledge base repository. The second technique allows to measure in real-time the estimated trustworthiness of event detection based on: a) sensors false alarm rates; b) uncertainties indices associated to correlation operators. We apply those techniques to case-studies of physical security for metro railways. © Springer International Publishing Switzerland 201
Performance Evaluation of Video Analytics for Surveillance On-Board Trains
No full textReal-time video-surveillance systems are nowadays widespread in several applications, including public transportation. In those applications, the use of automatic video content analytics (VCA) is being increasingly adopted to support human operators in control rooms. However, VCA is only effective when its performances are such to reduce the number of false positive alarms below acceptability thresholds while still detecting events of interest. In this paper, we report the results of the evaluation of a VCA system installed on a rail transit vehicle. With respect to fixed installations, on-board ones feature specific constraints on camera installation, obstacles, environment, etc. Several VCA performance evaluation metrics have been considered, both frame-based and object-based, computed by a tool developed in Matlab. We compared the results obtained using a commercial VCA system with the ones produced by an open-source one, showing the higher performance of the former in all test conditions. © 2013 Springer-Verlag.</p
Ensuring Cyber-Security in Smart Railway Surveillance with SHIELD
Full text linkModern railways feature increasingly complex embedded computing systems for surveillance, that are moving towards fully wireless smart-sensors. Those systems are aimed at monitoring system status from a physical-security viewpoint, in order to detect intrusions and other environmental anomalies. However, the same systems used for physical-security surveillance are vulnerable to cyber-security threats, since they feature distributed hardware and software architectures often interconnected by ‘open networks’, like wireless channels and the Internet. In this paper, we show how the integrated approach to Security, Privacy and Dependability (SPD) in embedded systems provided by the SHIELD framework (developed within the EU funded pSHIELD and nSHIELD research projects) can be applied to railway surveillance systems in order to measure and improve their SPD level. SHIELD implements a layered architecture (node, network, middleware and overlay) and orchestrates SPD mechanisms based on ontology models, appropriate metrics and composability. The results of prototypical application to a real-world demonstrator show the effectiveness of SHIELD and justify its practical applicability in industrial settings
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
The METRIP Tool
No full textThis chapter describes the results of the work conducted within the METRIP project in order to define a tool-chain supporting the methodological approach to the protection of railway infrastructures. The proposed tool-chain allows for: (a) modelling the RIS infrastructure, attack scenarios and protection technologies, (b) generating quantitative models to perform vulnerability analyses, and (c) generating and solving integer linear programming covering models to determine the optimal design choice in the development of physical protection systems. The chapter illustrates the functional and logical architecture of the tool-chain and describes the realization of a prototype to demonstrate the feasibility and effectiveness of the proposed approach
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