Methods and systems for a web crawler scheduler that utilizes sitemaps from websites are described. The active device array substrate includes scan lines, data lines, and pixel units. The primary switching circuit operates to turn on an energizing of the primary winding when the integrated sampled voltage indicates that the flux density of the transformer, after a transfer of energy between primary and secondary windings, lowers to a predetermined level. Decompression of the records from the block codes compressed above is also described. An annular V-shaped groove formed in the other side of the outer race is staked.