scholarly journals Distributed optimisation and control of graph Laplacian eigenvalues for robust consensus via an adaptive multilayer strategy

2017 ◽  
Author(s):  
L. C. Kempton ◽  
G. Herrmann ◽  
M. di Bernardo
Keyword(s):  
Graph Laplacian ◽  
Laplacian Eigenvalues ◽  
And Control ◽  
Robust Consensus

Responsible Eigenvalue Approach for Stability Analysis and Control Design of a Single-Delay Large-Scale System With Random Coupling Strengths

2010 ◽  
Author(s):  
Wei Qiao ◽  
Rifat Sipahi
Keyword(s):  
Stability Problem ◽  
Large Scale ◽  
Linear Time ◽  
Mimo System ◽  
Single Agent ◽  
Graph Laplacian ◽  
Control Synthesis ◽  
Coupling Strengths ◽  
And Control ◽  
Delay Margin

A class of linear time-invariant (LTI) consensus system with multiple agents and communication delays among the agents is studied. The delay margin of this MIMO system, that is, the largest amount of the delay that the system can withstand without loosing stability, can be studied by the authors’ Responsible Eigenvalue (RE) concept. RE is able to compress the considered stability problem into the stability problem of a single agent system, from which RE captures the delay margin of the entire MIMO system. RE is used here to design controllers for the MIMO system for the objective of increasing the delay margin. Case studies demonstrate connections between coupling strengths, graph Laplacian, the delay margin of a large-scale consensus system, and control synthesis.

scholarly journals Natural Graph Wavelet Packet Dictionaries

2021 ◽  
Vol 27 (3) ◽  
Author(s):  
Alexander Cloninger ◽  
Haotian Li ◽  
Naoki Saito
Keyword(s):  
Wavelet Packet ◽  
Graph Laplacian ◽  
Laplacian Eigenvalues ◽  
Street Networks ◽  
Shannon Wavelet ◽  
Frequency Interpretation ◽  
Arbitrary Graphs

AbstractWe introduce a set of novel multiscale basis transforms for signals on graphs that utilize their “dual” domains by incorporating the “natural” distances between graph Laplacian eigenvectors, rather than simply using the eigenvalue ordering. These basis dictionaries can be seen as generalizations of the classical Shannon wavelet packet dictionary to arbitrary graphs, and do not rely on the frequency interpretation of Laplacian eigenvalues. We describe the algorithms (involving either vector rotations or orthogonalizations) to construct these basis dictionaries, use them to efficiently approximate graph signals through the best basis search, and demonstrate the strengths of these basis dictionaries for graph signals measured on sunflower graphs and street networks.

scholarly journals Statistical Inference Using GLEaM Model with Spatial Heterogeneity and Correlation between Regions

2022 ◽  
Author(s):  
Yixuan Tan ◽  
Yuan Zhang ◽  
Xiuyuan Cheng ◽  
Xiao-Hua Zhou
Keyword(s):  
Simulated Data ◽  
Graph Laplacian ◽  
Stochastic Dynamic ◽  
Real World Data ◽  
Transmission Parameters ◽  
Step Procedure ◽  
Proposed Model ◽  
Spatial And Temporal Heterogeneity ◽  
Laplacian Regularization ◽  
And Control

A better understanding of the various patterns in the coronavirus disease 2019 (COVID-19) spread in different parts of the world is crucial to its prevention and control. Motivated by the celebrated GLEaM model (Balcan et al., 2010 [1]), this paper proposes a stochastic dynamic model to depict the evolution of COVID-19. The model allows spatial and temporal heterogeneity of transmission parameters and involves transportation between regions. Based on the proposed model, this paper also designs a two-step procedure for parameter inference, which utilizes the correlation between regions through a prior distribution that imposes graph Laplacian regularization on transmission parameters. Experiments on simulated data and real-world data in China and Europe indicate that the proposed model achieves higher accuracy in predicting the newly confirmed cases than baseline models.

Control of Metal Alloy Oxidation with Electric Fields

1973 ◽  
Vol 31 ◽  
pp. 164-165
Author(s):  
R. R. Dils ◽  
P. S. Follansbee
Keyword(s):  
Electric Fields ◽  
Oxidation Process ◽  
Base Alloy ◽  
Oxide Surface ◽  
Platinum Electrodes ◽  
Insulating Layer ◽  
Iron Base Alloy ◽  
Alloy Oxidation ◽  
Aluminum Oxide Layer ◽  
And Control

Electric fields have been applied across oxides growing on a high temperature alloy and control of the oxidation of the material has been demonstrated. At present, three-fold increases in the oxidation rate have been measured in accelerating fields and the oxidation process has been completely stopped in a retarding field.The experiments have been conducted with an iron-base alloy, Pe 25Cr 5A1 0.1Y, although, in principle, any alloy capable of forming an adherent aluminum oxide layer during oxidation can be used. A specimen is polished and oxidized to produce a thin, uniform insulating layer on one surface. Three platinum electrodes are sputtered on the oxide surface and the specimen is reoxidized.

Evidence for a Blood Ganglion Barrier in the Superior Cervical Ganglion of the Rat

1982 ◽  
Vol 40 ◽  
pp. 204-204
Author(s):  
D. M. DePace
Keyword(s):  
Blood Vessels ◽  
Superior Cervical Ganglion ◽  
Peripheral Nerves ◽  
Time Schedule ◽  
Transmission Electron ◽  
Cervical Ganglion ◽  
The Central Nervous System ◽  
Cervical Ganglia ◽  
Capillary Circulation ◽  
And Control

The majority of blood vessels in the superior cervical ganglion possess a continuous endothelium with tight junctions. These same features have been associated with the blood brain barrier of the central nervous system and peripheral nerves. These vessels may perform a barrier function between the capillary circulation and the superior cervical ganglion. The permeability of the blood vessels in the superior cervical ganglion of the rat was tested by intravenous injection of horseradish peroxidase (HRP). Three experimental groups of four animals each were given intravenous HRP (Sigma Type II) in a dosage of.08 to.15 mg/gm body weight in.5 ml of.85% saline. The animals were sacrificed at five, ten or 15 minutes following administration of the tracer. Superior cervical ganglia were quickly removed and fixed by immersion in 2.5% glutaraldehyde in Sorenson's.1M phosphate buffer, pH 7.4. Three control animals received,5ml of saline without HRP. These were sacrificed on the same time schedule. Tissues from experimental and control animals were reacted for peroxidase activity and then processed for routine transmission electron microscopy.

Effects of renovascular hypertension on rat adrenal zona glomerulosa

1978 ◽  
Vol 36 (2) ◽  
pp. 582-583
Author(s):  
G. Mazzocchi ◽  
P. Rebuffat ◽  
C. Robba ◽  
P. Vassanelli ◽  
G. G. Nussdorfer
Keyword(s):  
Renovascular Hypertension ◽  
Left Kidney ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Zona Glomerulosa ◽  
Ultrastructural Changes ◽  
Albino Rats ◽  
Left Renal Artery ◽  
Angiotensin System ◽  
And Control

It is well known that the rat adrenal zona glomerulosa steroidogenic activity is controlled by the renin-angiotensin system. The ultrastructural changes in the rat zona glomerulosa cells induced by renovascular hypertension were described previously, but as far as we are aware no correlated biochemical and morphometric investigations were performed.Twenty adult male albino rats were divided into 2 experimental groups. One group was subjected to restriction of blood flow to the left kidney by the application of a silver clip about the left renal artery. The other group was sham-operated and served as a control. Renovascular hypertension developed in about 10 days: sistolic blood pressure averaged 165 ± 6. 4 mmHg, whereas it was about 110 ± 3. 8 mmHg in the control animals. The hypertensive and control rats were sacrificed 20 days after the operation. The blood was collected and plasma renin activity was determined by radioimmunological methods. The aldosterone concentration was radioimmunologically assayed both in the plasma and in the homogenate of the left capsular adrenal gland.

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