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Comparison of order statistics in a random sequence to the same statistics with I.I.D. variables

Jean-Louis Bon, Eugen Păltănea (2006)

ESAIM: Probability and Statistics

The paper is motivated by the stochastic comparison of the reliability of non-repairable k -out-of- n systems. The lifetime of such a system with nonidentical components is compared with the lifetime of a system with identical components. Formally the problem is as follows. Let U i , i = 1 , . . . , n , be positive independent random variables with common distribution F . For λ i > 0 and μ > 0 , let consider X i = U i / λ i and Y i = U i / μ , i = 1 , . . . , n . Remark that this is no more than a change of scale for each term. For k { 1 , 2 , . . . , n } , let us define X k : n to be the k th order statistics...

Comparison of order statistics in a random sequence to the same statistics with i.i.d. variables

Jean-Louis Bon, Eugen Păltănea (2005)

ESAIM: Probability and Statistics

The paper is motivated by the stochastic comparison of the reliability of non-repairable k-out-of-n systems. The lifetime of such a system with nonidentical components is compared with the lifetime of a system with identical components. Formally the problem is as follows. Let Ui,i = 1,...,n, be positive independent random variables with common distribution F. For λi > 0 and µ > 0, let consider Xi = Ui/λi and Yi = Ui/µ, i = 1,...,n. Remark that this is no more than a change of scale for each...

Conditional Markov chains - construction and properties

Tomasz R. Bielecki, Jacek Jakubowski, Mariusz Niewęgłowski (2015)

Banach Center Publications

In this paper we study finite state conditional Markov chains (CMCs). We give two examples of CMCs, one which admits intensity, and another one, which does not admit an intensity. We also give a sufficient condition under which a doubly stochastic Markov chain is a CMC. In addition we provide a method for construction of conditional Markov chains via change of measure.

Conservation property of symmetric jump processes

Jun Masamune, Toshihiro Uemura (2011)

Annales de l'I.H.P. Probabilités et statistiques

Motivated by the recent development in the theory of jump processes, we investigate its conservation property. We will show that a jump process is conservative under certain conditions for the volume-growth of the underlying space and the jump rate of the process. We will also present examples of jump processes which satisfy these conditions.

Constrained optimality problem of Markov decision processes with Borel spaces and varying discount factors

Xiao Wu, Yanqiu Tang (2021)

Kybernetika

This paper focuses on the constrained optimality of discrete-time Markov decision processes (DTMDPs) with state-dependent discount factors, Borel state and compact Borel action spaces, and possibly unbounded costs. By means of the properties of so-called occupation measures of policies and the technique of transforming the original constrained optimality problem of DTMDPs into a convex program one, we prove the existence of an optimal randomized stationary policies under reasonable conditions.

Cut-off for large sums of graphs

Bernard Ycart (2007)

Annales de l’institut Fourier

If L is the combinatorial Laplacian of a graph, exp ( - L t ) converges to a matrix with identical coefficients. The speed of convergence is measured by the maximal entropy distance. When the graph is the sum of a large number of components, a cut-off phenomenon may occur: before some instant the distance to equilibrium tends to infinity; after that instant it tends to 0 . A sufficient condition for cut-off is given, and the cut-off instant is expressed as a function of the gap and eigenvectors of components....

Cutoff for samples of Markov chains

Bernard Ycart (2010)

ESAIM: Probability and Statistics

We study the convergence to equilibrium of n-samples of independent Markov chains in discrete and continuous time. They are defined as Markov chains on the n-fold Cartesian product of the initial state space by itself, and they converge to the direct product of n copies of the initial stationary distribution. Sharp estimates for the convergence speed are given in terms of the spectrum of the initial chain. A cutoff phenomenon occurs in the sense that as n tends to infinity, the total variation...

Dependent defaults and credit migrations

Tomasz R. Bielecki, Marek Rutkowski (2003)

Applicationes Mathematicae

The paper deals with the modelling of mutually dependent default times of several credit names through the intensity-based approach. We extend to the case of multiple ratings some previous results due to Schmidt (1998), Kusuoka (1999) and Jarrow and Yu (2001). The issue of the arbitrage valuation of simple basket credit derivatives is also briefly examined. We argue that our approach leads, in some cases, to a significant reduction of the dimensionality of the valuation problem at hand.

Directed forests with application to algorithms related to Markov chains

Piotr Pokarowski (1999)

Applicationes Mathematicae

This paper is devoted to computational problems related to Markov chains (MC) on a finite state space. We present formulas and bounds for characteristics of MCs using directed forest expansions given by the Matrix Tree Theorem. These results are applied to analysis of direct methods for solving systems of linear equations, aggregation algorithms for nearly completely decomposable MCs and the Markov chain Monte Carlo procedures.

Dynamic programming for an investment/consumption problem in illiquid markets with regime-switching

Paul Gassiat, Fausto Gozzi, Huyên Pham (2015)

Banach Center Publications

We consider an illiquid financial market with different regimes modeled by a continuous time finite-state Markov chain. The investor can trade a stock only at the discrete arrival times of a Cox process with intensity depending on the market regime. Moreover, the risky asset price is subject to liquidity shocks, which change its rate of return and volatility, and induce jumps on its dynamics. In this setting, we study the problem of an economic agent optimizing her expected utility from consumption...

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