enabling the recovery of the suspected elements and subsequent conservation of the
networked system with regards to its reliability, availability, and consequent
extension of RT applicability as a whole [1, 3–5].
When full recovery cannot be achieved, preventive measures can reduce the
level of danger, risk, and allows graceful degradation of services running on networked systems.
For networked systems the Process of Checking (PC) reliability and consequent
availability degradation, and the execution of Forward and Backward Tracing are
independent in principle. Therefore, they can be considered as sequential as well in
parallel. The PC (Process of Checking) which can also be regarded as Process of
Maintenance (PM), can be started any time when required, possible or convenient
[4, 5].
The aim is to perform PC well in advance when current mission reliability of
networked system is higher than threshold reliability defined and in such a manner
that when critical applications are running the networked system does not reach the
predefined threshold reliability. Note that the combination of processes of checking
and the recovery have an impact on the reliability of a networked system as a
whole. The gradient associated to the reliability change is a function of the quality
of checking, success of recovery and the quality of maintenance [4, 5].
The Process of Maintenance should also include the execution of both (Forward
and Backward) Tracing algorithms with harder conditions and reconfiguration of
networked systems if necessary. According to [4, 5] it would be interesting to shift
networked system in real-time maintenance with preventive measures against
threats. This approach enables to increase mission reliability and availability of
networked systems.
Recoverability could be measured using comparisons of standard networked
system against a system with RT maintenance implementation. For the analysis and
evaluation of the impact of recoverability implementation on networked system let
us follow the notation on [4, 5] and assume:
(a) A constant failure rates
(b) Maintenance is not ideal and coverage is less than 100%
(c) Minimum acceptable reliability threshold is introduced as before.
There are other assumptions related to checking process that need to be considered.
For instance, the mission reliability function with introduced recoverability and
online checking for networked systems is grounded on the following assumptions:
(a) The coverage is not 100%. The coverage is 100a%, 0 < a < 1, and this
parameter is assumed to be constant during al preventive maintenance actions.
(b) Preventive maintenance should be instantaneous and might not have a negative
impact on the networked system.
(c) The MR 0 which represents the threshold of acceptable mission reliability is
provided.
(d) T PM represents a function of several variables, such as a, k and MR 0 .
18.4 Recoverability Costs
263
networked system with regards to its reliability, availability, and consequent
extension of RT applicability as a whole [1, 3–5].
When full recovery cannot be achieved, preventive measures can reduce the
level of danger, risk, and allows graceful degradation of services running on networked systems.
For networked systems the Process of Checking (PC) reliability and consequent
availability degradation, and the execution of Forward and Backward Tracing are
independent in principle. Therefore, they can be considered as sequential as well in
parallel. The PC (Process of Checking) which can also be regarded as Process of
Maintenance (PM), can be started any time when required, possible or convenient
[4, 5].
The aim is to perform PC well in advance when current mission reliability of
networked system is higher than threshold reliability defined and in such a manner
that when critical applications are running the networked system does not reach the
predefined threshold reliability. Note that the combination of processes of checking
and the recovery have an impact on the reliability of a networked system as a
whole. The gradient associated to the reliability change is a function of the quality
of checking, success of recovery and the quality of maintenance [4, 5].
The Process of Maintenance should also include the execution of both (Forward
and Backward) Tracing algorithms with harder conditions and reconfiguration of
networked systems if necessary. According to [4, 5] it would be interesting to shift
networked system in real-time maintenance with preventive measures against
threats. This approach enables to increase mission reliability and availability of
networked systems.
Recoverability could be measured using comparisons of standard networked
system against a system with RT maintenance implementation. For the analysis and
evaluation of the impact of recoverability implementation on networked system let
us follow the notation on [4, 5] and assume:
(a) A constant failure rates
(b) Maintenance is not ideal and coverage is less than 100%
(c) Minimum acceptable reliability threshold is introduced as before.
There are other assumptions related to checking process that need to be considered.
For instance, the mission reliability function with introduced recoverability and
online checking for networked systems is grounded on the following assumptions:
(a) The coverage is not 100%. The coverage is 100a%, 0 < a < 1, and this
parameter is assumed to be constant during al preventive maintenance actions.
(b) Preventive maintenance should be instantaneous and might not have a negative
impact on the networked system.
(c) The MR 0 which represents the threshold of acceptable mission reliability is
provided.
(d) T PM represents a function of several variables, such as a, k and MR 0 .
18.4 Recoverability Costs
263