341 research outputs found
Power Imbalance Detection in Smart Grid via Grid Frequency Deviations: A Hidden Markov Model based Approach
We detect the deviation of the grid frequency from the nominal value (i.e.,
50 Hz), which itself is an indicator of the power imbalance (i.e., mismatch
between power generation and load demand). We first pass the noisy estimates of
grid frequency through a hypothesis test which decides whether there is no
deviation, positive deviation, or negative deviation from the nominal value.
The hypothesis testing incurs miss-classification errors---false alarms (i.e.,
there is no deviation but we declare a positive/negative deviation), and missed
detections (i.e., there is a positive/negative deviation but we declare no
deviation). Therefore, to improve further upon the performance of the
hypothesis test, we represent the grid frequency's fluctuations over time as a
discrete-time hidden Markov model (HMM). We note that the outcomes of the
hypothesis test are actually the emitted symbols, which are related to the true
states via emission probability matrix. We then estimate the hidden Markov
sequence (the true values of the grid frequency) via maximum likelihood method
by passing the observed/emitted symbols through the Viterbi decoder.
Simulations results show that the mean accuracy of Viterbi algorithm is at
least \% greater than that of hypothesis test.Comment: 5 pages, 6 figures, accepted by IEEE VTC conference, Fall 2018
editio
Exploiting Lack of Hardware Reciprocity for Sender-Node Authentication at the PHY Layer
This paper proposes to exploit the so-called reciprocity
parameters (modelling non-reciprocal communication
hardware) to use them as decision metric for binary hypothesis
testing based authentication framework at a receiver node Bob.
Specifically, Bob first learns the reciprocity parameters of the
legitimate sender Alice via initial training. Then, during the test
phase, Bob first obtains a measurement of reciprocity parameters
of channel occupier (Alice, or, the intruder Eve). Then, with
ground truth and current measurement both in hand, Bob
carries out the hypothesis testing to automatically accept (reject)
the packets sent by Alice (Eve). For the proposed scheme, we
provide its success rate (the detection probability of Eve), and
its performance comparison with other schemes
Coordination and Antenna Domain Formation in Cloud-RAN systems
We study here the problem of Antenna Domain Formation (ADF) in cloud RAN
systems, whereby multiple remote radio-heads (RRHs) are each to be assigned to
a set of antenna domains (ADs), such that the total interference between the
ADs is minimized. We formulate the corresponding optimization problem, by
introducing the concept of \emph{interference coupling coefficients} among
pairs of radio-heads. We then propose a low-overhead algorithm that allows the
problem to be solved in a distributed fashion, among the aggregation nodes
(ANs), and establish basic convergence results. Moreover, we also propose a
simple relaxation to the problem, thus enabling us to characterize its maximum
performance. We follow a layered coordination structure: after the ADs are
formed, radio-heads are clustered to perform coordinated beamforming using the
well known Weighted-MMSE algorithm. Finally, our simulations show that using
the proposed ADF mechanism would significantly increase the sum-rate of the
system (with respect to random assignment of radio-heads).Comment: 7 pages, IEEE International Conference on Communications 2016 (ICC
2016
Golimumab: A novel human anti-TNF-alpha monoclonal antibody for the treatment of rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis
INTRODUCTION: The introduction of tumor necrosis factor-alpha (TNF-alpha) inhibitors represented a significant advance in the management of rheumatoid arthritis (RA) and other chronic inflammatory diseases. Although three TNF-alpha inhibitors have been approved for the treatment of RA by the US Food and Drug Administration (FDA) and the European Medicinal Products Evaluation Agency (EMEA), not all patients achieve a satisfactory clinical improvement with these therapeutic agents. The mode of administration of these medications is inconvenient for some patients. AIMS: Golimumab is a novel anti-TNF-alpha monoclonal antibody that is in clinical development for the treatment of RA, psoriatic arthritis (PsA), and ankylosing spondylitis (AS), either as a first-line biologic therapy or an alternative after other TNF-alpha inhibitors have been discontinued. This review summarizes the development of, and clinical evidence achieved with, golimumab.
EVIDENCE REVIEW: Golimumab has demonstrated significant efficacy in randomized, double-blind, placebo-controlled trials when administered subcutaneously once every four weeks. It has been generally well tolerated in clinical trials and demonstrates a safety profile comparable with currently available TNF-alpha inhibitors.
OUTCOMES SUMMARY: Golimumab has been confirmed to be an effective treatment for patients with RA, PsA, and AS in phase III clinical trials as evaluated by traditional measures of disease activity, such as signs and symptoms, as well as measures of physical function, patient reported outcomes, and health economic measures. The efficacy and safety profile of golimumab in RA, PsA, and AS appears to be similar to other anti-TNF agents. However, golimumab has the potential advantage of once monthly subcutaneous administration and the possibility of both subcutaneous and intravenous administration
Distributed Beamforming with Wirelessly Powered Relay Nodes
This paper studies a system where a set of relay nodes harvest energy
from the signal received from a source to later utilize it when forwarding the
source's data to a destination node via distributed beamforming. To this end,
we derive (approximate) analytical expressions for the mean SNR at destination
node when relays employ: i) time-switching based energy harvesting policy, ii)
power-splitting based energy harvesting policy. The obtained results facilitate
the study of the interplay between the energy harvesting parameters and the
synchronization error, and their combined impact on mean SNR. Simulation
results indicate that i) the derived approximate expressions are very accurate
even for small (e.g., ), ii) time-switching policy by the relays
outperforms power-splitting policy by at least dB.Comment: 4 pages, 3 figures, accepted for presentation at IEEE VTC 2017 Spring
conferenc
Channel Impulse Response-based Distributed Physical Layer Authentication
In this preliminary work, we study the problem of {\it distributed}
authentication in wireless networks. Specifically, we consider a system where
multiple Bob (sensor) nodes listen to a channel and report their {\it
correlated} measurements to a Fusion Center (FC) which makes the ultimate
authentication decision. For the feature-based authentication at the FC,
channel impulse response has been utilized as the device fingerprint.
Additionally, the {\it correlated} measurements by the Bob nodes allow us to
invoke Compressed sensing to significantly reduce the reporting overhead to the
FC. Numerical results show that: i) the detection performance of the FC is
superior to that of a single Bob-node, ii) compressed sensing leads to at least
overhead reduction on the reporting channel at the expense of a small
( dB) SNR margin to achieve the same detection performance.Comment: 6 pages, 5 figures, accepted for presentation at IEEE VTC 2017 Sprin
Assessment of high sensitivity C-reactive protein in ETT positive patients with normal coronary angiogram
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