Preventive Maintenance of a Multi-State Device Subject to Internal Failure and Damage Due to External Shocks

2014 ◽  
Vol 63 (2) ◽  
pp. 646-660 ◽  
Author(s):  
Juan Eloy Ruiz-Castro
Keyword(s):  
Preventive Maintenance ◽  
External Shocks ◽  
State Device

scholarly journals Optimizing a Multi-State Cold-Standby System with Multiple Vacations in the Repair and Loss of Units

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 913
Author(s):  
Juan Eloy Ruiz-Castro
Keyword(s):  
Preventive Maintenance ◽  
External Shocks ◽  
Matrix Analytic Methods ◽  
Multiple Vacation ◽  
Phase Type ◽  
Arrival Processes ◽  
Repair Facility ◽  
The Times ◽  
Set Up ◽  
Algorithmic Form

A complex multi-state redundant system with preventive maintenance subject to multiple events is considered. The online unit can undergo several types of failure: both internal and those provoked by external shocks. Multiple degradation levels are assumed as both internal and external. Degradation levels are observed by random inspections and, if they are major, the unit goes to a repair facility where preventive maintenance is carried out. This repair facility is composed of a single repairperson governed by a multiple vacation policy. This policy is set up according to the operational number of units. Two types of task can be performed by the repairperson, corrective repair and preventive maintenance. The times embedded in the system are phase type distributed and the model is built by using Markovian Arrival Processes with marked arrivals. Multiple performance measures besides the transient and stationary distribution are worked out through matrix-analytic methods. This methodology enables us to express the main results and the global development in a matrix-algorithmic form. To optimize the model, costs and rewards are included. A numerical example shows the versatility of the model.

Two Years after the Crisis: Do Risks of the Second Wave Become Stronger?

2011 ◽  
pp. 4-20
Author(s):  
M. Ershov
Keyword(s):  
High Risk ◽  
World Economy ◽  
External Shocks ◽  
Global Imbalances ◽  
Russian Economy ◽  
The World ◽  
The Future ◽  
Second Wave

With signs of normalization seemingly in place in the world economy, a number of problems show the possibility of aggravation in the future. The volume of derivatives in American banks grows significantly, high risk instruments are back in place and their use becomes more active, global imbalances increase. All of the above requires thorough approaches when creating mechanisms which can neutralize external shocks for the Russian economy and make it possible to develop in the new post-crisis environment.

Fiscal rules: Excessive limitation or indispensable instrument of fiscal sustainability?

2016 ◽  
pp. 5-29 ◽  
Author(s):  
E. Gurvich ◽  
I. Sokolov
Keyword(s):  
Historical Data ◽  
Federal Budget ◽  
Fiscal Sustainability ◽  
Fiscal Rules ◽  
External Shocks ◽  
Base Price ◽  
Depth Analysis ◽  
Fiscal Balance ◽  
Lower Size ◽  
Budget Expenditure

In-depth analysis of international and Russia’s experiences with implementing fiscal rules is presented. Theoretical and empirical evidences are suggested in favor of retaining the present fiscal rules with some modifications aimed at ensuring: a) a relatively stable level of federal budget expenditure with guaranteed full execution of all commitments; b) countercyclical fiscal policy, based on flexibleand proper reaction to revenue changes; and c) robustness of fiscal rules to internal and external shocks. The main new features suggested include modified calculation of the oil base price, different measurement of cyclical fiscal revenues, lower size of structural fiscal balance, and thorough specification of sources for each item of the balance. The modified rules envisage increased flexibility by relaxing to a pre-set extent and for a pre-set time spending limits in response to extreme shocks. The suggested version of fiscal rules has been tested by application to historical data for 2005-2015, and macro projections for 2015-2025.

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