A novel tunnel structure is described that enables tunnel diode behavior to be exhibited even in material systems in which extremely heavy doping is impossible and only moderate or light doping levels may be achieved. In one embodiment, the device sends a \u201cblind\u201d registration message to an SIP server, with the private IP address of the device being translated to the public IP address by the NAT and with the SIP server registering the \u201coriginator\u201d address in the header. The transistor sizing and evaluating the combination of said transistor-level representation and standard-cell mapping are performed iteratively to meet delay, size and power constraints for CMOS. The main components of an example multi-level monitoring framework may include a probe runner component for probing the cloud service, a monitor component for generating alerts based on probe results, and a responder component for processing the alerts and taking appropriate actions to improve the cloud service performance. A plurality of intersections within the polygon is determined, and link weights between the intersections are assigned based on at least one condition factor. In addition, the thermal conductivity of the heat transfer fluid emulsion is greater than the thermal conductivity of the heat transfer fluid.