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

Shrinkage Function And Its Applications In Matrix Approximation

The shrinkage function is widely used in matrix low-rank approximation, compressive sensing, and statistical estimation. In this article, an elementary derivation of the shrinkage function is given. In addition, applications of the shrinkage function are demonstrated in solving several well-known problems, together with a new result in matrix approximation

Microvascular decompression for hemifacial spasm: Outcome on spasm and complications. A review

Over the last decades microvascular decompression (MVD) has been established as the curative treatment of the primary Hemifacial Spasm (HFS), proven to be linked in almost all cases to a neurovascular compression of the facial nerve. Because the disease is not life-threatening and MVD not totally innocuous, efficacy and safety have to be weighted before decision taken of indicating surgery. The authors have been charged by the French Speaking Society of Neurosurgery to conduct a detailed evaluation of the probability of relief of the spasm that MVD is able to obtain, together with its potential complications. For the review, the authors have gone through the reports available from the Pubmed system. Eighty-two publications have been read and analysed, totalizing more than 10,000 operated cases. In most series, the percentage of patients with total relief ranged between 85% and 90%. Relief was obtained after a certain delay in as many as in 33%±8% of the patients in many series. For those, delay lasted around one year in 12% of them. When effect of MVD was considered achieved, relief remained permanent in all but 1%-2% of the long-term followed patients. As regards to complications, risk of permanent cranial nerve deficit was evaluated at 1%-2% for facial palsy, 2%-3% for non-functional hearing loss, 0.5%-1% for lower cranial nerve dysfunction. Risk of stroke was at 0.1% and mortality at 0.1%. CSF leakage and related complications could be reduced at less than 2% in most series provided careful closing techniques be applied. Complications were at a higher rate in repeated MVD. MVD is an effective curative method for almost all the patients affected with primary HFS. Because MVD for HFS is functional surgery, scrupulous consideration of its potential risks, together with the ways to avoid complications are of paramount importance. When MVD is estimated to have failed, it is wise to wait one year before considering to repeat surgery, as number of patients may benefit from delayed effect. This is the more so as important as repeated surgery entails a higher rate of complications

When Both Transmitting and Receiving Energies Matter: An Application of Network Coding in Wireless Body Area Networks

A network coding scheme for practical implementations of wireless body area networks is presented, with the objective of providing reliability under low-energy constraints. We propose a simple network layer protocol for star networks, adapting redundancy based on both transmission and reception energies for data and control packets, as well as channel conditions. Our numerical results show that even for small networks, the amount of energy reduction achievable can range from 29% to 87%, as the receiving energy per control packet increases from equal to much larger than the transmitting energy per data packet. The achievable gains increase as a) more nodes are added to the network, and/or b) the channels seen by different sensor nodes become more asymmetric.Comment: 10 pages, 7 figures, submitted to the NC-Pro Workshop at IFIP Networking Conference 2011, and to appear in the conference proceedings, published by Springer-Verlag, in the Lecture Notes in Computer Science (LNCS) serie

Rapid Wireless Capacitor Charging Using a Multi-Tapped Inductively-Coupled Secondary Coil

This paper presents an inductive coupling system designed to wirelessly charge ultra-capacitors used as energy storage elements. Although ultra-capacitors offer the native ability to rapidly charge, it is shown that standard inductive coupling circuits only deliver maximal power for a specific load impedance which depends on coil geometries and separation distances. Since a charging ultra-capacitor can be modeled as an increasing instantaneous impedance, maximum power is thus delivered to the ultra-capacitor at only a single point in the charging interval, resulting in a longer than optimal charging time. Analysis of inductive coupling theory reveals that the optimal load impedance can be modified by adjusting the secondary coil inductance and resonant tuning capacitance. A three-tap secondary coil is proposed to dynamically modify the optimal load impedance throughout the capacitor charging interval. Measurement results show that the proposed architecture can expand its operational range by up to 2.5 × and charge a 2.5 F ultra-capacitor to 5 V upwards of 3.7 × faster than a conventional architecture.Semiconductor Research Corporation. Interconnect Focus Cente

Anatomie du nerf alvéolaire inférieur

International audienceLe nerf alvéolaire inférieur présente un trajet global commun, mais aussi une variabilité anatomique (type trifurqué, bifurqué, ou plexiforme, foramen men-tonnier unique ou double, rond ou ovale) qui doit tout de même inciter à la plus grande prudence, par une imagerie systématique de type scanner mandibulaire, avant tout geste à proximité du nerf pour détecter les éventuelles variation