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Near-Zero-Power Temperature Sensing via Tunneling Currents Through Complementary Metal-Oxide-Semiconductor Transistors.
Temperature sensors are routinely found in devices used to monitor the environment, the human body, industrial equipment, and beyond. In many such applications, the energy available from batteries or the power available from energy harvesters is extremely limited due to limited available volume, and thus the power consumption of sensing should be minimized in order to maximize operational lifetime. Here we present a new method to transduce and digitize temperature at very low power levels. Specifically, two pA current references are generated via small tunneling-current metal-oxide-semiconductor field effect transistors (MOSFETs) that are independent and proportional to temperature, respectively, which are then used to charge digitally-controllable banks of metal-insulator-metal (MIM) capacitors that, via a discrete-time feedback loop that equalizes charging time, digitize temperature directly. The proposed temperature sensor was integrated into a silicon microchip and occupied 0.15 mm2 of area. Four tested microchips were measured to consume only 113 pW with a resolution of 0.21 °C and an inaccuracy of ±1.65 °C, which represents a 628× reduction in power compared to prior-art without a significant reduction in performance
Second-harmonic generation in graded metallic films
We study the effective second-harmonic generation (SHG) susceptibility in
graded metallic films by invoking the local field effects exactly, and further
numerically demonstrate that the graded metallic films can serve as a novel
optical material for producing a broad structure in both the linear and SHG
response and an enhancement in the SHG signal.Comment: 10 pages, 2 EPS figures. Minor revision
Social-aware Opportunistic Routing Protocol based on User's Interactions and Interests
Nowadays, routing proposals must deal with a panoply of heterogeneous
devices, intermittent connectivity, and the users' constant need for
communication, even in rather challenging networking scenarios. Thus, we
propose a Social-aware Content-based Opportunistic Routing Protocol, SCORP,
that considers the users' social interaction and their interests to improve
data delivery in urban, dense scenarios. Through simulations, using synthetic
mobility and human traces scenarios, we compare the performance of our solution
against other two social-aware solutions, dLife and Bubble Rap, and the
social-oblivious Spray and Wait, in order to show that the combination of
social awareness and content knowledge can be beneficial when disseminating
data in challenging networks
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