where Tcurrent and Tlast synchronization denote the current time and the time of the last synchronization, respectively.
Once the last synchronization process expires, each node is able to estimate its current synchronization error with the objective of updating this value.
Timestamp transfer On a synchronization event, only the parts of the dataset changed since the last synchronization are transferred between the mobile device and the remote system using a last-changed timestamp.
Mathematical transfer On a synchronization event, only the parts of the dataset changed since the last synchronization are transferred between the mobile device and the remote system using a mathematical method.
For the second case (2), before delivering a message, our method estimates the synchronization error caused by the distance to the sink node, independently of the last synchronization process.
This estimation avoids performing complex operations in the sensor nodes, and considers two sources for the desynchronization: the clock drift since the last synchronization and the number of hops between source and destination.
In this equation, PSYNC ix, WI) includes the following two probabilities: (i) probability of an independent event of a synchronization process during the WI x triggered by a distant node to the sink, and (ii) probability of the non-independent events after a long time since the last synchronization.
When applying the changes, it also detects if there is any conflict, i.e., the same data has been changed on both stores since the last synchronization.
This web service accepts queries by either a period when the event happened, or by a date of last synchronization between the EMPRES-i and OpenFluDB databases.
Its main method takes as input either a period of the event date or the last synchronization date, as well as the serotype involved (all parameters are optional).
We distinguish two methods: short-lasting synchronization and long-lasting synchronization.
