Described herein are improved configurations for resonator for wireless power transfer that includes a magnetic material having at least one hollow section, and at least one electrical conductor wrapped around the magnetic material. A size of the set of candidate content descriptors may be optimized, for example, to reduce false positive matching errors, query latencies andor index tree traversal times, at least in part by determining a number of child nodes to traverse based at least in part on current traverse level andor traverse neighborhood thresholds. The transistor further includes a second tunneling structure disposed between the base and collector electrodes. Each de-duplication client can de-duplicate a digital sequence by breaking the sequence into blocks and identifying redundant blocks already stored in the shared architecture.