OPTIMAL BACKWARD AND BACKUP POLICIES IN RELIABILITY THEORY

Optimal Backward and Backup Policies in Reliability Theory

Abstract We are sometimes faced with the problem of searching for the actual failure time of a unit when it has failed until time t0. This is called a backward time problem of how much time we go back to search for the failure time from time t0, and is solved by using the reversed failure rate. This paper proposes an extended model of multiple backward trials in which we find the actual failure...

Optimal Policies for a Database System with Two Backup Schemes

This paper considers two backup schemes for a database system: a database is updated at a nonhomogeneous Poisson process and an amount of updated files accumulates additively. To ensure the safety of data, full backups are performed at time NT or when the total updated files have exceeded a threshold level K, and between them, cumulative backups as one of incremental backups are made at periodi...

Optimal Backup Policies for a Database System with Periodic Incremental Backup

This paper considers the following backup scheme for a database system: a database is updated at a nonhomogeneous Poisson process and an amount of updated files accumulates additively. To ensure the safety of data, full backup are performed at time NT=L or when the database fails, whichever occurs first, and between them, incremental backups are made at periodic times iT (i=1, 2, ..., N-1) so a...

Optimality Of Monetary And Fiscal Policies In Iran: An Application Of The Stochastic Optimal Control Theory

Optimal Primary-Backup Protocols

One way to implement a fault-tolerant service is to employ multiple sites that fail independently. The state of the service is replicated and distributed among these sites, and updates are coordinated so that even when a subset of the sites fail, the service remains available. A common approach to structuring such replicated services is to designate one site as the primary and all the others as...