399 research outputs found
When Backpressure Meets Predictive Scheduling
Motivated by the increasing popularity of learning and predicting human user
behavior in communication and computing systems, in this paper, we investigate
the fundamental benefit of predictive scheduling, i.e., predicting and
pre-serving arrivals, in controlled queueing systems. Based on a lookahead
window prediction model, we first establish a novel equivalence between the
predictive queueing system with a \emph{fully-efficient} scheduling scheme and
an equivalent queueing system without prediction. This connection allows us to
analytically demonstrate that predictive scheduling necessarily improves system
delay performance and can drive it to zero with increasing prediction power. We
then propose the \textsf{Predictive Backpressure (PBP)} algorithm for achieving
optimal utility performance in such predictive systems. \textsf{PBP}
efficiently incorporates prediction into stochastic system control and avoids
the great complication due to the exponential state space growth in the
prediction window size. We show that \textsf{PBP} can achieve a utility
performance that is within of the optimal, for any ,
while guaranteeing that the system delay distribution is a
\emph{shifted-to-the-left} version of that under the original Backpressure
algorithm. Hence, the average packet delay under \textsf{PBP} is strictly
better than that under Backpressure, and vanishes with increasing prediction
window size. This implies that the resulting utility-delay tradeoff with
predictive scheduling beats the known optimal tradeoff for systems without prediction
Spin alignment of vector mesons from quark dynamics in a rotating medium
Vorticities in heavy-ion collisions (HICs) are supposed to induce spin
alignment and polarization phenomena of quarks and mesons. In this work, we
analyze the spin alignment of vector mesons and induced by
rotation from quark dynamics in the framework of the Nambu-Jona-Lasinio (NJL)
model. The rotating angular velocity induces mass splitting of spin components
for vector mesons . This behavior contributes to the spin
alignment of vector mesons in an equilibrium medium and naturally
explains the negative deviation of for vector mesons.
Incidentally, the positive deviation of under the magnetic
field can also be easily understood from quark dynamics.Comment: 12 pages, 8 figure
Ginkgetin aglycone exerts anti-osteoporotic effect via regulation of NOX4/Akt/PI3K pathway
Purpose: To investigate the protective effect of Ginkgetin aglycone (GA) on ovariectomy-induced osteoporosis in rats, as well as the mechanism of action involved.
Methods: Adult female Wistar rats (n = 40) were separated into four group: normal control, ovariectomy (OVR), 100 mg GA/kg dose, and 200 mg GA/kg dose. The rats were ovariectomized using standard procedures, except for those in normal control group. Rats in the two treatment groups received 100 or 200 mg GA/kg orally for a period of 12 weeks. Biochemical assays were performed on the urine and blood. Markers of bone formation and mediators of inflammation were assessed. Bone microarchitectural changes were examined using micro-CT scanner, while Western blotting was used to determine the expressions of NOX4, NF-κB p65, PI3K, Akt and JNK proteins in rat femurs.
Results: Phosphorus and calcium levels in the serum varied among different groups. Levels of calcium, phosphorus and creatinine decreased (p < 0.01) significantly to a greater extent in the urine of GA group than in that of OVR group (p < 0.05). Interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α) and osteocalcin (OC) levels and the activity of alkaline phosphatase (ALP) decreased more in GA group than in OVR group. In GA-treated group, bone mineral density (BMD) was enhanced in a dose dependent manner than OVR group (p < 0.05). Treatment with GA ameliorated altered bone microarchitecture in OVR rats. Treatment of osteoporotic rats with GA led to significant and dosedependent decrease in the expressions of JNK, NOX4, NF-κB p65 and PI3K, and (p < 0.05) increase in the expression of Akt in femur tissue.
Conclusion: In conclusion, result of study proves the anti-osteoporotic activity of GA is exerted via regulation of NOX4/PI3K/Akt pathway
Assessment of Long-Term Watershed Management on Reservoir Phosphorus Concentrations and Export Fluxes.
Source water nutrient management to prevent eutrophication requires critical strategies to reduce watershed phosphorus (P) loadings. Shanxi Drinking-Water Source Area (SDWSA) in eastern China experienced severe water quality deterioration before 2010, but showed considerable improvement following application of several watershed management actions to reduce P. This paper assessed the changes in total phosphorus (TP) concentrations and fluxes at the SDWSA outlet relative to watershed anthropogenic P sources during 2005⁻2016. Overall anthropogenic P inputs decreased by 21.5% over the study period. Domestic sewage, livestock, and fertilizer accounted for (mean ± SD) 18.4 ± 0.6%, 30.1 ± 1.9%, and 51.5 ± 1.5% of total anthropogenic P inputs during 2005⁻2010, compared to 24.3 ± 2.7%, 8.8 ± 10.7%, and 66.9 ± 8.0% for the 2011⁻2016 period, respectively. Annual average TP concentrations in SDWSA decreased from 0.041 ± 0.019 mg/L in 2009 to 0.025 ± 0.013 mg/L in 2016, a total decrease of 38.2%. Annual P flux exported from SDWSA decreased from 0.46 ± 0.04 kg P/(ha·a) in 2010 to 0.25 ± 0.02 kg P/(ha·a) in 2016, a decrease of 44.9%. The success in reducing TP concentrations was mainly due to the development of domestic sewage/refuse collection/treatment and improved livestock management. These P management practices have prevented harmful algal blooms, providing for safe drinking water
Decentralized Federated Learning with Asynchronous Parameter Sharing for Large-scale IoT Networks
Federated learning (FL) enables wireless terminals to collaboratively learn a
shared parameter model while keeping all the training data on devices per se.
Parameter sharing consists of synchronous and asynchronous ways: the former
transmits parameters as blocks or frames and waits until all transmissions
finish, whereas the latter provides messages about the status of pending and
failed parameter transmission requests. Whatever synchronous or asynchronous
parameter sharing is applied, the learning model shall adapt to distinct
network architectures as an improper learning model will deteriorate learning
performance and, even worse, lead to model divergence for the asynchronous
transmission in resource-limited large-scale Internet-of-Things (IoT) networks.
This paper proposes a decentralized learning model and develops an asynchronous
parameter-sharing algorithm for resource-limited distributed IoT networks. This
decentralized learning model approaches a convex function as the number of
nodes increases, and its learning process converges to a global stationary
point with a higher probability than the centralized FL model. Moreover, by
jointly accounting for the convergence bound of federated learning and the
transmission delay of wireless communications, we develop a node scheduling and
bandwidth allocation algorithm to minimize the transmission delay. Extensive
simulation results corroborate the effectiveness of the distributed algorithm
in terms of fast learning model convergence and low transmission delay.Comment: 17 pages, 8 figures, to appear in IEEE Internet of Things Journa
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