1,720,964 research outputs found
Improving stability of PCA-based network anomaly detection by means of kernel-PCA
No full textIn the last years, the problem of detecting anomalies and attacks by statistically inspecting the network traffic has been attracting more and more research efforts. As a result, many different solutions have been proposed. Nonetheless, the poor performance offered by the proposed detection methods, as well as the difficulty of properly tuning and training these systems, make the detection of network anomalies still an open issue. In this paper, we face the problem by proposing a way to improve the performance of anomaly detection. In more detail, we propose a novel network anomaly detection method that, by means of kernel-PCA, is able to overcome the limitations of the 'classical' PCA-based methods, while retaining good performance in detecting network attacks and anomalies
A network control application enabling Software-Defined Quality of Service
No full textThe constant growth in IT as well as the increase of users and services requirements are making communication networking more and more complex to manage. This is why there has been the need to look for new approaches. One very promising solution is Software Defined Networking (SDN) that decouples the data and control planes, having one centralized controller for the network. This gives chances to control and manage the network as desired, thus opening many new possibilities. In this work we chose to exploit SDN to enable QoS control, starting from existing tools (Floodlight) and making modifications in order to better exploit their potential. A new network control application for end-to-end QoS provisioning is built on top of Floodlight and validated in an emulated SDN environment
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
Design and development of management functions for distributed monitoring based on SDN-based network
No full textIn the latest years, we have seen a fast evolution of Internet systems and a remarkable increase of the number and variety of services required. The need of new architectural solutions has led to the creation of new tools that allow to develop more flexible and dynamic networks. Software Defined Networking (SDN) goes in this direction, offering a new way to manage networks, based on programmability, virtualization of the network and centralization of decision processes. In this article we will analyse how it is possible to deploy these new tools to realize some fundamental network functions also for monitoring systems. We will also show a real testbed where we implemented the functions we describe, and we will show the experimental results obtained with it
Design and evaluation of SDN-based orchestration system for cloud data centers
No full textWe present an SDN-based orchestration system that enables automated and coordinated arrangement of both computing and network resources in virtualized DC environments. The orchestrator is validated through a set of simulations, as well as through experiments carried out in a real laboratory. Results show that the proposed orchestration system improves the service requests acceptance rate and the utilization of network resources, while minimizing degradations of the user experience. Thus, DC resources can be effectively exploited, and different management objectives (e.g., load balancing, energy saving) can be reached
Advances in LTE network monitoring: A step towards an SDN solution
No full textMonitoring operations in today's mobile networks is becoming a more and more challenging task due to the higher bandwidth and technological complexity brought by LTE. The paper summarizes some relevant problems that arose in the tests of LTE equipment carried out at Telecom Italia Lab (TILAB, the R&D center of Telecom Italia), and presents an ongoing project that aims at realizing a flexible hardware/software platform to cope with these problems at reasonable costs. The ultimate goal of this research is to develop a Software Defined Networking (SDN) measurements platform, which permits to easily and dynamically configure the measurement devices involved in the test and monitoring functions according to the requirements defined by the operator. Furthermore, the paper proposes the integration of the designed framework in a realistic lab environment, and discusses the improvements introduced to the actual architecture
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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