Methods and apparatus for adjusting transmission power in wireless networks are provided. The apparatus comprises a substrate having a planar surface and first and second electrodes located on the planar surface. A cost per unit flow is associated with each link of the directed graph. The method further includes performing, by a time-series-to-sequential-pattern converter, a time-series-to-sequential-pattern conversion by mining invariant relationships between the set of time series, and discovering sequential message patterns and association rules in the plurality of heterogeneous logs using the invariant relationships. Each database object to be protected is given an attribute of a security class.