1,697 research outputs found

    Autonomic computing meets SCADA security

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    © 2017 IEEE. National assets such as transportation networks, large manufacturing, business and health facilities, power generation, and distribution networks are critical infrastructures. The cyber threats to these infrastructures have increasingly become more sophisticated, extensive and numerous. Cyber security conventional measures have proved useful in the past but increasing sophistication of attacks dictates the need for newer measures. The autonomic computing paradigm mimics the autonomic nervous system and is promising to meet the latest challenges in the cyber threat landscape. This paper provides a brief review of autonomic computing applications for SCADA systems and proposes architecture for cyber security

    Autonomic computing architecture for SCADA cyber security

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    Cognitive computing relates to intelligent computing platforms that are based on the disciplines of artificial intelligence, machine learning, and other innovative technologies. These technologies can be used to design systems that mimic the human brain to learn about their environment and can autonomously predict an impending anomalous situation. IBM first used the term ‘Autonomic Computing’ in 2001 to combat the looming complexity crisis (Ganek and Corbi, 2003). The concept has been inspired by the human biological autonomic system. An autonomic system is self-healing, self-regulating, self-optimising and self-protecting (Ganek and Corbi, 2003). Therefore, the system should be able to protect itself against both malicious attacks and unintended mistakes by the operator

    Modelling exciton-phonon interactions in optically driven quantum dots

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    We provide a self-contained review of master equation approaches to modelling phonon effects in optically driven self-assembled quantum dots. Coupling of the (quasi) two-level excitonic system to phonons leads to dissipation and dephasing, the rates of which depend on the excitation conditions, intrinsic properties of the QD sample, and its temperature. We describe several techniques, which include weak-coupling master equations that are perturbative in the exciton-phonon coupling, as well as those based on the polaron transformation that can remain valid for strong phonon interactions. We additionally consider the role of phonons in altering the optical emission characteristics of quantum dot devices, outlining how we must modify standard quantum optics treatments to account for the presence of the solid-state environment.Comment: Invited Topical Review, 26 pages, 7 figures. V2 - close to published version, 28 pages, 9 figures. Minor changes to text, added a few new references and two new figure

    Model of the optical emission of a driven semiconductor quantum dot: phonon-enhanced coherent scattering and off-resonant sideband narrowing

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    We study the crucial role played by the solid-state environment in determining the photon emission characteristics of a driven quantum dot. For resonant driving, we predict a phonon-enhancement of the coherently emitted radiation field with increasing driving strength, in stark contrast to the conventional expectation of a rapidly decreasing fraction of coherent emission with stronger driving. This surprising behaviour results from thermalisation of the dot with respect to the phonon bath, and leads to a nonstandard regime of resonance fluorescence in which significant coherent scattering and the Mollow triplet coexist. Off-resonance, we show that despite the phonon influence, narrowing of dot spectral sideband widths can occur in certain regimes, consistent with an experimental trend.Comment: Published version. 5 pages, 2 figures, plus 4 page supplement. Title changed, figure 1 revised, various edits and additions to the tex

    Autonomous monitoring framework for resource-constrained environments

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    Acknowledgments The research described here is supported by the award made by the RCUK Digital Economy programme to the dot.rural Digital Economy Hub, reference: EP/G066051/1. URL: http://www.dotrural.ac.uk/RemoteStream/Peer reviewedPublisher PD

    Autoencoder based anomaly detection for SCADA networks

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    Supervisory control and data acquisition (SCADA) systems are industrial control systems that are used to monitor critical infrastructures such as airports, transport, health, and public services of national importance. These are cyber physical systems, which are increasingly integrated with networks and internet of things devices. However, this results in a larger attack surface for cyber threats, making it important to identify and thwart cyber-attacks by detecting anomalous network traffic patterns. Compared to other techniques, as well as detecting known attack patterns, machine learning can also detect new and evolving threats. Autoencoders are a type of neural network that generates a compressed representation of its input data and through reconstruction loss of inputs can help identify anomalous data. This paper proposes the use of autoencoders for unsupervised anomaly-based intrusion detection using an appropriate differentiating threshold from the loss distribution and demonstrate improvements in results compared to other techniques for SCADA gas pipeline dataset

    Colorectal Cancer Screening Behaviors among American Indians in the Midwest

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    Colorectal cancer is the second most diagnosed cancer among American Indians and is also the second leading cause of cancer death. We used a community-based participatory approach to conduct a mixed methods study to examine colorectal cancer screening behaviors. Here we report on the screening behaviors of our focus group participants (n=153). There were significant gender differences in the colorectal cancer screening rates for FOBT and colonoscopy. Although over 80% of participants reported having health insurance, only 35% of males over 50 years old and 57% of females reported ever having a colonoscopy. More research is needed to identify the causes of gender differences in colorectal cancer screening rates among American Indians. The results of the current study provide new information on the prevalence of colorectal cancer screening among American Indians living in the Midwestern (Kansas and Missouri) portion of the country

    A general approach to quantum dynamics using a variational master equation: Application to phonon-damped Rabi rotations in quantum dots

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    We develop a versatile master equation approach to describe the non-equilibrium dynamics of a two-level system in contact with a bosonic environment, which allows for the exploration of a wide range of parameter regimes within a single formalism. As an experimentally relevant example, we apply this technique to the study of excitonic Rabi rotations in a driven quantum dot, and compare its predictions to the numerical Feynman integral approach. We find excellent agreement between the two methods across a generally difficult range of parameters. In particular, the variational master equation technique captures effects usually considered to be non-perturbative, such as multi-phonon processes and bath-induced driving renormalisation, and can give reliable results even in regimes in which previous master equation approaches fail.Comment: 5 pages, 2 figures. Published version, revised title, minor changes to the tex
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