4,593 research outputs found
Multi-Layer Cyber-Physical Security and Resilience for Smart Grid
The smart grid is a large-scale complex system that integrates communication
technologies with the physical layer operation of the energy systems. Security
and resilience mechanisms by design are important to provide guarantee
operations for the system. This chapter provides a layered perspective of the
smart grid security and discusses game and decision theory as a tool to model
the interactions among system components and the interaction between attackers
and the system. We discuss game-theoretic applications and challenges in the
design of cross-layer robust and resilient controller, secure network routing
protocol at the data communication and networking layers, and the challenges of
the information security at the management layer of the grid. The chapter will
discuss the future directions of using game-theoretic tools in addressing
multi-layer security issues in the smart grid.Comment: 16 page
Body mass index, abdominal fatness, fat mass and the risk of atrial fibrillation: a systematic review and doseâresponse meta-analysis of prospective studies
Different adiposity measures have been associ- ated with increased risk of atrial fibrillation, however, results have previously only been summarized for BMI. We therefore conducted a systematic review and meta- analysis of prospective studies to clarify the association between different adiposity measures and risk of atrial fibrillation. PubMed and Embase databases were searched up to October 24th 2016. Summary relative risks (RRs) were calculated using random effects models. Twenty-nine unique prospective studies (32 publications) were included. Twenty-five studies (83,006 cases, 2,405,381 participants) were included in the analysis of BMI and atrial fibrillation. The summary RR was 1.28 (95% confidence interval: 1.20â1.38, I 2 = 97%) per 5 unit increment in BMI, 1.18 (95% CI: 1.12â1.25, I 2 = 73%, n = 5) and 1.32 (95% CI: 1.16â1.51, I 2 = 91%, n = 3) per 10 cm increase in waist and hip circumference, respectively, 1.09 (95% CI: 1.02â1.16, I 2 = 44%, n = 4) per 0.1 unit increase in waist- to-hip ratio, 1.09 (95% CI: 1.02â1.16, I 2 = 94%, n = 4) per 5 kg increase in fat mass, 1.10 (95% CI: 0.92â1.33, I 2 = 90%, n = 3) per 10% increase in fat percentage, 1.10 (95% CI: 1.08â1.13, I 2 = 74%, n = 10) per 5 kg increase in weight, and 1.08 (95% CI: 0.97â1.19, I 2 = 86%, n = 2) per 5% increase in weight gain. The association between BMI and atrial fibrillation was non- linear, p nonlinearity \ 0.0001, with a stronger association at higher BMI levels, however, increased risk was observed even at a BMI of 22â24 compared to 20. In conclusion, general and abdominal adiposity and higher body fat mass increase the risk of atrial fibrillation
Systematic review and network meta-analysis on the efficacy of evolocumab and other therapies for the management of lipid levels in hyperlipidemia
Background: The proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors evolocumab and alirocumab substantially reduce lowâdensity lipoprotein cholesterol (LDLâC) when added to statin therapy in patients who need additional LDLâC reduction.
Methods and Results: We conducted a systematic review and network metaâanalysis of randomized trials of lipidâlowering therapies from database inception through August 2016 (45 058 records retrieved). We found 69 trials of lipidâlowering therapies that enrolled patients requiring further LDLâC reduction while on maximally tolerated mediumâ or highâintensity statin, of which 15 could be relevant for inclusion in LDLâC reduction networks with evolocumab, alirocumab, ezetimibe, and placebo as treatment arms. PCSK9 inhibitors significantly reduced LDLâC by 54% to 74% versus placebo and 26% to 46% versus ezetimibe. There were significant treatment differences for evolocumab 140 mg every 2 weeks at the mean of weeks 10 and 12 versus placebo (â74.1%; 95% credible interval â79.81% to â68.58%), alirocumab 75 mg (â20.03%; 95% credible interval â27.32% to â12.96%), and alirocumab 150 mg (â13.63%; 95% credible interval â22.43% to â5.33%) at â„12 weeks. Treatment differences were similar in direction and magnitude for PCSK9 inhibitor monthly dosing. Adverse events were similar between PCSK9 inhibitors and control. Rates of adverse events were similar between PCSK9 inhibitors versus placebo or ezetimibe.
Conclusions: PCSK9 inhibitors added to mediumâ to highâintensity statin therapy significantly reduce LDLâC in patients requiring further LDLâC reduction. The network metaâanalysis showed a significant treatment difference in LDLâC reduction for evolocumab versus alirocumab
Robust Decentralized Secondary Frequency Control in Power Systems: Merits and Trade-Offs
Frequency restoration in power systems is conventionally performed by
broadcasting a centralized signal to local controllers. As a result of the
energy transition, technological advances, and the scientific interest in
distributed control and optimization methods, a plethora of distributed
frequency control strategies have been proposed recently that rely on
communication amongst local controllers.
In this paper we propose a fully decentralized leaky integral controller for
frequency restoration that is derived from a classic lag element. We study
steady-state, asymptotic optimality, nominal stability, input-to-state
stability, noise rejection, transient performance, and robustness properties of
this controller in closed loop with a nonlinear and multivariable power system
model. We demonstrate that the leaky integral controller can strike an
acceptable trade-off between performance and robustness as well as between
asymptotic disturbance rejection and transient convergence rate by tuning its
DC gain and time constant. We compare our findings to conventional
decentralized integral control and distributed-averaging-based integral control
in theory and simulations
A Learning-Based Framework for Two-Dimensional Vehicle Maneuver Prediction over V2V Networks
Situational awareness in vehicular networks could be substantially improved
utilizing reliable trajectory prediction methods. More precise situational
awareness, in turn, results in notably better performance of critical safety
applications, such as Forward Collision Warning (FCW), as well as comfort
applications like Cooperative Adaptive Cruise Control (CACC). Therefore,
vehicle trajectory prediction problem needs to be deeply investigated in order
to come up with an end to end framework with enough precision required by the
safety applications' controllers. This problem has been tackled in the
literature using different methods. However, machine learning, which is a
promising and emerging field with remarkable potential for time series
prediction, has not been explored enough for this purpose. In this paper, a
two-layer neural network-based system is developed which predicts the future
values of vehicle parameters, such as velocity, acceleration, and yaw rate, in
the first layer and then predicts the two-dimensional, i.e. longitudinal and
lateral, trajectory points based on the first layer's outputs. The performance
of the proposed framework has been evaluated in realistic cut-in scenarios from
Safety Pilot Model Deployment (SPMD) dataset and the results show a noticeable
improvement in the prediction accuracy in comparison with the kinematics model
which is the dominant employed model by the automotive industry. Both ideal and
nonideal communication circumstances have been investigated for our system
evaluation. For non-ideal case, an estimation step is included in the framework
before the parameter prediction block to handle the drawbacks of packet drops
or sensor failures and reconstruct the time series of vehicle parameters at a
desirable frequency
DOC 2016-03 Master of Professional Accountancy (MPAcc), Full Proposal
Legislative Authorit
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