scholarly journals Maximization of availability of 1-out-of-2:G repairable dependent system

1989 ◽  
Vol 21 (03) ◽  
pp. 717-720
Author(s):  
B. H. Joshi ◽  
A. D. Dharmadhikari
Keyword(s):  
Stochastic Process ◽  
Steady State ◽  
Lower Bound ◽  
Upper Bounds ◽  
The Other ◽  
Expected Number ◽  
Component Failure ◽  
Component System ◽  
Component Failure Rates ◽  
Repair Facility

The IFR property of the stochastic process governing a one-component system supported by an inactive standby and a repair facility when the lifetime of one component and the repair time of the other component are dependent, is established. We solve the problem of selecting repair rates to maximize the steady-state availability for given component failure rates when a lower bound for the MTBF and upper bounds for the steady-state expected number of repairs of the components per unit time and expected number of failures of the system per unit time are given.

scholarly journals Maximization of availability of 1-out-of-2:G repairable dependent system

1989 ◽  
Vol 21 (3) ◽  
pp. 717-720 ◽  
Author(s):  
B. H. Joshi ◽  
A. D. Dharmadhikari
Keyword(s):  
Stochastic Process ◽  
Steady State ◽  
Lower Bound ◽  
Upper Bounds ◽  
The Other ◽  
Expected Number ◽  
Component Failure ◽  
Component System ◽  
Component Failure Rates ◽  
Repair Facility

The IFR property of the stochastic process governing a one-component system supported by an inactive standby and a repair facility when the lifetime of one component and the repair time of the other component are dependent, is established. We solve the problem of selecting repair rates to maximize the steady-state availability for given component failure rates when a lower bound for the MTBF and upper bounds for the steady-state expected number of repairs of the components per unit time and expected number of failures of the system per unit time are given.

scholarly journals A flow-map model for analyzing pseudothresholds in fault-tolerant quantum computing

2006 ◽  
Vol 6 (3) ◽  
pp. 193-212 ◽  
Author(s):  
K.M. Svore ◽  
A.W. Cross ◽  
I.L. Chuang ◽  
A.V. Aho
Keyword(s):  
Quantum Computing ◽  
Fault Tolerance ◽  
Quantum Computer ◽  
Fault Tolerant ◽  
Upper Bounds ◽  
Component Failure ◽  
Simulation Procedure ◽  
Component Failure Rates ◽  
Flow Map ◽  
Noise Models

An arbitrarily reliable quantum computer can be efficiently constructed from noisy components using a recursive simulation procedure, provided that those components fail with probability less than the fault-tolerance threshold. Recent estimates of the threshold are near some experimentally achieved gate fidelities. However, the landscape of threshold estimates includes pseudothresholds, threshold estimates based on a subset of components and a low level of the recursion. In this paper, we observe that pseudothresholds are a generic phenomenon in fault-tolerant computation. We define pseudothresholds and present classical and quantum fault-tolerant circuits exhibiting pseudothresholds that differ by a factor of $4$ from fault-tolerance thresholds for typical relationships between component failure rates. We develop tools for visualizing how reliability is influenced by recursive simulation in order to determine the asymptotic threshold. Finally, we conjecture that refinements of these methods may establish upper bounds on the fault-tolerance threshold for particular codes and noise models.

scholarly journals On the Information Ratio of Graphs with Many Leaves

2019 ◽  
Vol 73 (1) ◽  
pp. 97-108
Author(s):  
Máté Gyarmati ◽  
Péter Ligeti
Keyword(s):  
Lower Bound ◽  
Secret Sharing ◽  
Complete Graph ◽  
Upper Bounds ◽  
Entropy Method ◽  
The Other ◽  
Secret Sharing Schemes ◽  
Lower And Upper Bounds ◽  
Information Ratio ◽  
Recursive Constructions

Abstract We investigate the information ratio of graph-based secret sharing schemes. This ratio characterizes the efficiency of a scheme measured by the amount of information the participants must remember for each bits in the secret. We examine the information ratio of several systems based on graphs with many leaves, by proving non-trivial lower and upper bounds for the ratio. On one hand, we apply the so-called entropy method for proving that the lower bound for the information ratio of n-sunlet graphs composed of a 1-factor between the vertices of a cycle Cn and n independent vertices is 2. On the other hand, some symmetric and recursive constructions are given that yield the upper bounds. In particular, we show that the information ratio of every graph composed of a 1-factor between a complete graph Kn and at most 4 independent vertices is smaller than 2.

scholarly journals Markov Process in Varying Value in Production by Machinery with Two Components

2019 ◽  
Vol 8 (10) ◽  
pp. 3411-3414
Keyword(s):  
Steady State ◽  
Markov Process ◽  
The Other ◽  
Component Failure ◽  
Expected Cost ◽  
Paper Production ◽  
Cost Of Production ◽  
Steady State Probabilities

In this paper production and availability of machinery for production are considered. Here a machinery of production with two components is considered and that production is full when the machinery is working with both the components functioning well. But there is a chance that the whole machinery may dysfunction because of failure of both components in which case the production comes to a standstill and it is worst crisis. The other possibility is that one of the components may fail but still the machine continues functioning but with less efficiency. The production may continue and if the other component also fails the production completely stops and the situation is critical. When the machine is in one component failure, the failed part may be a repaired and machine can be made to work with full efficiency. But when both components fail, should be renewed as a package and then the production should start. Under such conditions found the steady state probabilities and the rate of crisis and the expected cost of production.

Simulation of Normal Differentiable Stochastic Process of Ice Loads

2017 ◽  
Author(s):  
Petr Zvyagin
Keyword(s):  
Stochastic Process ◽  
Autocorrelation Function ◽  
Critical Level ◽  
Process Approach ◽  
The Other ◽  
Normal Process ◽  
Expected Number ◽  
Stationary Model ◽  
Tank Experiment ◽  
Ice Loads

Ice loads time series should be treated in the other way than separate independent ice loads observations. The stochastic process approach can provide information about such important characteristic as mean length of signal’s outcome beyond some critical level and expected number of such outcomes. The paper considers global ice loads registered in an ice tank experiment with a cylindrical indenter of 100 mm width. The autocorrelation function is fitted in a manner that the observed load process is differentiable. The study conducted in the paper demonstrates that characteristics, such as the number outcomes beyond some critical level and the time spent off this level, are governed in the same way as parameters of a stationary differentiable normal process. Normal stationary model of ice loads process allows its simulation, if autocorrelation function is given. In the paper, such simulation is performed.

scholarly journals Bounds for the electrical resistance for homogeneous conducting body of rotation

2021 ◽  
Vol 11 (5) ◽  
pp. 104-122
Author(s):  
István Ecsedi ◽  
Ákos József Lengyel ◽  
Attila Baksa ◽  
Dávid Gönczi
Keyword(s):  
Steady State ◽  
Lower Bound ◽  
Electric Current ◽  
Electrical Resistance ◽  
Current Flow ◽  
Electrical Conductance ◽  
Upper Bounds ◽  
The Body ◽  
Lower And Upper Bounds ◽  
Electric Current Flow

A mathematical model is developed for the steady-state electric current flow through in a homogeneous isotropic conductor whose shape is a body of rotation. The body of rotation considered is bounded by the coordinate surfaces of an orthogonal curvilinear coordinate system. The equations of the Maxwell’s theory of electric current flow in a homogeneous solid conductor body are used to formulate the corresponding electric boundary value problem. The studied steady-state conduction problem is axisymmetric. The determination of the steady motion of charges is based on the concept of the electrical conductance of the conductors the inverse of which is the electrical resistance. The exact (strict) value of the electrical resistance is known only for bodies with very simple shapes, therefore, the principles and the methods that can be used for creating lower and upper bounds to the numerical value of electrical resistance (electrical conductance) are important. The derivation of the upper and lower bound formulae for the electrical conductance of axisymmetric ring-like conductor is based on the two types of Cauchy–Schwarz inequality. The condition of equality of the derived lower and upper bounds is examined. Several examples illustrate the applications of the derived upper and lower bound formulae.

Fidelity of J1269 and J24523

2007 ◽  
Vol 35 (2) ◽  
pp. 94-117 ◽  
Author(s):  
James A. Popio ◽  
John R. Luchini
Keyword(s):  
Steady State ◽  
Rolling Resistance ◽  
Test Methods ◽  
The Other ◽  
Reference Condition ◽  
Test Standards

Abstract This study compares data from the two Society of Automotive Engineers test methods for rolling resistance: J-2452 (Stepwise Coast-Down) and J-1269 (Equilibrium) steady state. The ability of the two methods to evaluate tires was examined by collecting data for 12 tires. The data were analyzed and the data showed that the two methods ranked the tires the same after the data were regressed and the rolling resistance magnitude was calculated at the Standard Reference Condition. In addition, analysis of the two methods using this matched set of testing provided an opportunity to evaluate each of these test standards against the other. It was observed that each test has merits absent from the other.

scholarly journals Receptor-operated Ca2+ channels in gastric parietal cells: gastrin and carbachol induce Ca2+ influx in depleting intracellular Ca2+ stores

1993 ◽  
Vol 289 (1) ◽  
pp. 117-124 ◽  
Author(s):  
S Roche ◽  
J P Bali ◽  
R Magous
Keyword(s):  
Steady State ◽  
Receptor Activation ◽  
Parietal Cells ◽  
The Other ◽  
Bivalent Cation ◽  
Gtp Binding ◽  
Gastric Parietal Cells ◽  
Type Receptor ◽  
Ca2 Channels ◽  
Stimulation Of

The mechanism whereby gastrin-type receptor and muscarinic M3-type receptor regulate free intracellular Ca2+ concentration ([Ca2+]i) was studied in rabbit gastric parietal cells stimulated by either gastrin or carbachol. Both agonists induced a biphasic [Ca2+]i response: a transient [Ca2+]i rise, followed by a sustained steady state depending on extracellular Ca2+. Gastrin and carbachol also caused a rapid and transient increase in Mn2+ influx (a tracer for bivalent-cation entry). Pre-stimulation of cells with one agonist drastically decreased both [Ca2+]i increase and Mn2+ influx induced by the other. Neither diltiazem nor pertussistoxin treatment had any effect on agonist-stimulated Mn2+ entry. Thapsigargin, a Ca(2+)-pump inhibitor, induced a biphasic [Ca2+]i increase, and enhanced the rate of Mn2+ entry. Preincubation of cells with thapsigargin inhibits the [Ca2+]i increase as well as Mn2+ entry stimulated by gastrin or by carbachol. Thapsigargin induced a weak but significant increase in Ins(1,4,5)P3 content, but this agent had no effect on the agonist-evoked Ins(1,4,5)P3 response. In permeabilized parietal cells, Ins(1,4,5)P3 and caffeine caused an immediate Ca2+ release from intracellular pools, followed by a reloading of Ca2+ pools which can be prevented in the presence of thapsigargin. We conclude that (i) gastrin and carbachol mobilize common Ca2+ intracellular stores, (ii) Ca2+ permeability secondary to receptor activation involves neither a voltage-sensitive Ca2+ channel nor a GTP-binding protein from the G1 family, and (iii) agonists regulate common Ca2+ channels in depleting intracellular Ca2+ stores.

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