Xiao Liu PhD Thesis.pdf - Faculty of Information and Communication ...

Table 3.2 Component 2: Temporal Consistency Monitoring
The first step is to select temporal checkpoints. Since it is normally too
expensive to conduct temporal verification at every activity point but insufficient to
conduct temporal verification only at a few pre-defined activity points, the target of
a checkpoint selection strategy (CSS) is to select only necessary and sufficient
activity points where potential temporal violations are detected. Therefore, the cost
of temporal verification will be minimised. In our framework, a minimum
probability time redundancy based checkpoint selection strategy is designed for
selecting only necessary and sufficient checkpoints given our probability based
temporal consistency model. Necessary and sufficient checkpoints serve as
important basis for all the subsequent steps. Details about the checkpoint selection
strategy will be presented in Chapter 6.
The second step is temporal verification. Temporal verification is to verify the
current temporal consistency state so as to determine whether a temporal violation
takes place and/or the level of current temporal violations. Given a specific temporal
consistency model which may define different types of temporal consistency states,
conventional temporal verification may need to be conducted for several times to
identify the current temporal consistency states. For example, in the conventional
multi-states based temporal consistency model, if the current temporal consistency
state is strong inconsistency, then the temporal verification process may be
30