1,720,964 research outputs found
Model and simulation of a real water distribution network to support emergency plans
No full textThis paper presents a water distribution network model to evaluate the impact of adverse events, such as faults and/or cyber-attacks, on a real water distribution system in a wider context which involves the interdependency with the electrical grid, in the frame of the Horizon 2020 project ATENA. The model has been developed by using a commercial simulator, which can address both the electrical and the water domain. Specific features and modules have been added to the simulator, in order to calculate the water level in tanks an important and missing metric to support emergency plans. The interdependency among the electricity grid and the water network is considered throughout pumps, which are at the same time electrical loads and hydraulic devices. Two use cases, dealing with faults or cyber-attacks against the electrical grid affecting critical pumps or treatment stations, are investigated and the simulation results are reported. İ 2018 2018 Dime università di Genova, dimeg university of calabria
Joint control of bandwidth and playout-delay for streaming traffic over faded links (Best Paper Award)
No full textIn this paper we develop an optimized control strategy for the connection bandwidth maximization over a time varying wireless channel, by jointly controlling the adaptive source rate and the client/playout buffering policy with constraints on the maximum connection bandwidth allowed at the Application (APP) layer, the queue-capacities available at the Data-Link (DL) layer and the average and peak transmit energies sustained by the Physical (PHY) layer. The main feature of the approach we follow lies in the fact that the maximization of the throughput is performed with respect to the channel state information as well as the occupancies of the transmitter and receiver buffers, taking into account also for the need to optimize the playout buffer service so to reduce the stream-jitter provided to the final user. The resulting optimal controllers operate in a Cross-Layer (CL) fashion that involves the APP, DL and PHY layers of the underlying protocol stack. Via a parameter-depending optimization we are able to handle the jitter of the stream provided to the final user without significant impact on the bandwidth performances. The carried out numerical tests give insight into the tradeoff among average throughput, delay and jitter attained by the optimized controllers. ©2010 IEEE
Optimized joint bandwidth and playout control for streaming-traffic over wireless-channels
No full textCyber attacks on scada of critical infrastructures by an Hybrid Testbed
No full textWith the emergence of the Internet of Things, SCADA (Supervisory Control and Data Acquisition), which constitutes the nervous system of Critical Infrastructures (CI), are becoming geographically distributed and more vulnerable to cyber attacks. SCADA boundaries to be protected are going well beyond the single plants. In the paper, an hybrid test bed is used to conduct cyber attacks on SCADA and to analyze consequences on it and, in turn, on its physical CI. The hybrid test bed is constituted by hardware devices and simulative models. Hardware devices are in charge of representing actual SCADA devices, while simulative models represent interdependent physical CI. The test bed is completed by an open source platform which reproduces cyber attacks, includes typical SCADA cyber protections and monitors SCADA data flow. Simulative models represent an interdependent active electrical grid, a gas and a water network in an urban district. Continuity of supply of grid customers under cyber attacks is investigated
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
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