4,280 research outputs found
Transfer Learning for Device Fingerprinting with Application to Cognitive Radio Networks
Primary user emulation (PUE) attacks are an emerging threat to cognitive
radio (CR) networks in which malicious users imitate the primary users (PUs)
signals to limit the access of secondary users (SUs). Ascertaining the identity
of the devices is a key technical challenge that must be overcome to thwart the
threat of PUE attacks. Typically, detection of PUE attacks is done by
inspecting the signals coming from all the devices in the system, and then
using these signals to form unique fingerprints for each device. Current
detection and fingerprinting approaches require certain conditions to hold in
order to effectively detect attackers. Such conditions include the need for a
sufficient amount of fingerprint data for users or the existence of both the
attacker and the victim PU within the same time frame. These conditions are
necessary because current methods lack the ability to learn the behavior of
both SUs and PUs with time. In this paper, a novel transfer learning (TL)
approach is proposed, in which abstract knowledge about PUs and SUs is
transferred from past time frames to improve the detection process at future
time frames. The proposed approach extracts a high level representation for the
environment at every time frame. This high level information is accumulated to
form an abstract knowledge database. The CR system then utilizes this database
to accurately detect PUE attacks even if an insufficient amount of fingerprint
data is available at the current time frame. The dynamic structure of the
proposed approach uses the final detection decisions to update the abstract
knowledge database for future runs. Simulation results show that the proposed
method can improve the performance with an average of 3.5% for only 10%
relevant information between the past knowledge and the current environment
signals.Comment: 6 pages, 3 figures, in Proceedings of IEEE 26th International
Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Hong
Kong, P.R. China, Aug. 201
Metrics and Algorithms for Processing Multiple Continuous Queries
Data streams processing is an emerging research area that is driven by the growing need for monitoring applications. A monitoring application continuously processes streams of data for interesting, significant, or anomalous events. Such applications include tracking the stock market, real-time detection of diseaseoutbreaks, and environmental monitoring via sensor networks.Efficient employment of those monitoring applications requires advanced data processing techniques that can support the continuous processing of unbounded rapid data streams. Such techniques go beyond the capabilities of the traditional store-then-query Data BaseManagement Systems. This need has led to a new data processing paradigm and created a new generation of data processing systems,supporting continuous queries (CQ) on data streams.Primary emphasis in the development of first generation Data Stream Management Systems (DSMSs) was given to basic functionality. However, in order to support large-scale heterogeneous applications that are envisioned for subsequent generations of DSMSs, greater attention willhave to be paid to performance issues. Towards this, this thesis introduces new algorithms and metrics to the current design of DSMSs.This thesis identifies a collection of quality ofservice (QoS) and quality of data (QoD) metrics that are suitable for a wide range of monitoring applications. The establishment of well-defined metrics aids in the development of novel algorithms that are optimal with respect to a particular metric. Our proposed algorithms exploit the valuable chances for optimization that arise in the presence of multiple applications. Additionally, they aim to balance the trade-off between the DSMS's overall performance and the performance perceived by individual applications. Furthermore, we provide efficient implementations of the proposed algorithms and we also extend them to exploit sharing in optimized multi-query plans and multi-stream CQs. Finally, we experimentally show that our algorithms consistently outperform the current state of the art
Places, Memories and Religious Identity: Muslim Places of Worship in Badakhshan Region of Tajikistan
This study examines the ways in which the Ismailis of the Badakhshan region of Tajikistan understand and relate to their sacred sites. It explores the sacred sites of Badakhshan within the framework of anthropological literature on space and place. Using the concept of chronotope, this study shows that the sacred sites disrupt the materialist and historiographic understanding of and relation to the spaces and places. Through the stories of the miracles of the saints, sacred sites validate and confirm the presence of the transcendent in the lived environment of the people. Beyond the legends about the miracles of the saints, sacred sites are chronotopes that evoke the memory of the Soviet campaigns against these places. Through the retrospective narratives about the Soviet past, people allocate the responsibility for the destruction and desecration of these sites at that period to members of their communities. Although these retrospective narratives are about recent events, they include transcendent intervention; that is, they show how these sites punished those that were involved in the Soviet campaigns against them. Moreover, through these discources and through their visitations to the sacred sites, people unconsciously attribute certain agency to them, which emerges in the relationship between people and these places. People seek the help of these sites to grant their wishes. In most cases, these wishes are about curing the seriously ill family member or curing infertility problems. In that sense, sacred sites help people to recapture the sense of agency in situations where they experience its loss. Therefore, sacred sites are chronotopes, the physical sites in the inhabited space of the community that incorporate and evoke the legends about the miracles of the saints, the stories about the recent Soviet past of these sites and the discourses about their current status in the life of the community. The stories and discources associated with the sacred sites affect and shape people’s perceptions and articulations of their inhabited spaces and places
Distributions of Stellar Systems Using Mathematica With Applications to Cataclysmic Variables and Planetary Nebulae
In this paper, Meisel's(2013) algorithm for the distribution of galaxies using Mathematica was used for the distributions of Cataclysmic Variables(CV) and Planetary Nebulae(PNe) . Data manipulationsare illustratedgenerally, through the Internet data sources and the implementation for Mathematica usage. The distributions are displayed in two dimensions ,the galactic longitude andgalactic latitude. The distributions of both CVs and the PNe are symmetric about the galactic plane, with high condensation of PNe towards the plane which supports the known fact that PNe are young. On the other hand ,the remarkable condensation the remarkable condensation at high galactic latitudes of CVs indicates that these objects are old
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