Abstract: Described herein is an implantable device comprising a radiation-sensitive element (such as a transistor) configured to modulate a current as a function of radiation exposure to the transistor; and an ultrasonic device comprising an ultrasonic transducer configured to emit an ultrasonic backscatter that encodes the radiation exposure to the transistor. Further described herein is an implantable device comprising a radiation-sensitive element (such as a diode) configured to generate an electrical signal upon encountering radiation; an integrated circuit configured to receive the electrical signal and modulate a current based on the received electrical signal; and an ultrasonic transducer configured to emit an ultrasonic backscatter based on the modulated current encoding information relating to the encountered radiation.

Abstract: Described herein is an implantable device comprising a radiation-sensitive element (such as a transistor) configured to modulate a current as a function of radiation exposure to the transistor; and an ultrasonic device comprising an ultrasonic transducer configured to emit an ultrasonic backscatter that encodes the radiation exposure to the transistor. Further described herein is an implantable device comprising a radiation-sensitive element (such as a diode) configured to generate an electrical signal upon encountering radiation; an integrated circuit configured to receive the electrical signal and modulate a current based on the received electrical signal; and an ultrasonic transducer configured to emit an ultrasonic backscatter based on the modulated current encoding information relating to the encountered radiation.

Abstract: A crystal-free radio includes an antenna; a receiver configured to communicate with the antenna; a local radio frequency (RF) oscillator configured to communicate with the receiver; and a clock circuit configured to communicate with the receiver and the local RF oscillator, the clock circuit having an electronic circuit oscillator. The local RF oscillator is a free-running oscillator. The clock circuit is configured to receive a calibration signal via a wireless network and calibrate the electronic circuit oscillator based on the received calibration signal, and the clock circuit is a crystal-free clock circuit.

Abstract: A crystal-free radio includes an antenna; a receiver configured to communicate with the antenna; a local radio frequency (RF) oscillator configured to communicate with the receiver; and a clock circuit configured to communicate with the receiver and the local RF oscillator, the clock circuit having an electronic circuit oscillator. The local RF oscillator is a free-running oscillator. The clock circuit is configured to receive a calibration signal via a wireless network and calibrate the electronic circuit oscillator based on the received calibration signal, and the clock circuit is a crystal-free clock circuit.

Abstract: Described herein is an implantable device comprising a radiation-sensitive element (such as a transistor) configured to modulate a current as a function of radiation exposure to the transistor; and an ultrasonic device comprising an ultrasonic transducer configured to emit an ultrasonic backscatter that encodes the radiation exposure to the transistor. Further described herein is an implantable device comprising a radiation-sensitive element (such as a diode) configured to generate an electrical signal upon encountering radiation; an integrated circuit configured to receive the electrical signal and modulate a current based on the received electrical signal; and an ultrasonic transducer configured to emit an ultrasonic backscatter based on the modulated current encoding information relating to the encountered radiation.

Abstract: Self managing a low power network is disclosed. A packet is received which includes network information and it is determined if a management action is required based at least in part on information in the packet. In the event that management action is required, the management action is performed wherein the management action is determined based at least in part on information in the packet.

Abstract: In a packet communication network, a method of packet switched transport is provided using digraphs defining paths among nodes in which a graph identifier, instead of a literal destination address, is used to determine paths through the network. The nodes themselves implement a real-time mesh of connectivity. Packets flow along paths that are available to them, flowing around obstructions such as dead nodes and lost links without need for additional computation, route request messages, or dynamic routing tree construction.

Abstract: A method for synchronizing a digraph network is disclosed. The method comprises receiving timing information from a first node at a second node over a first connection specified by a first digraph link, wherein the first digraph link is a directional link specifying routing information at the first node in a network, and wherein the network includes a plurality of nodes each with a plurality of digraph links. The method further comprises calculating a synchronized time using the received timing information and a local time and sending timing information from the second node to a third node over a second connection specified by a second digraph link.

Abstract: A method for a digraph linked network to provide subnetwork communication is disclosed. The method running a first superframe in a digraph linked network containing at least one digraph link wherein a digraph link is a directional link specifying routing information between a first node and a second node in the digraph linked network. The method further comprises running a second superframe in a digraph linked network containing at least one digraph link.

Abstract: A device for a node in a digraph network comprising is disclosed. The device comprises an internal time reference, a radio receiver, a radio transmitter. The device further comprises a temperature sensor for stabilizing the internal time reference against drifting with respect to an internal time reference of another node in the network and a microprocessor for managing the reception and transmission of information.

Abstract: A method of assigning cells in a superframe using digraph link information in a network of nodes is disclosed. The method comprises determining a total number of desired digraph links in the network of nodes wherein a digraph link is a directional link specifying routing information at each node in the network between said node and a second node, and wherein the network of nodes includes a plurality of nodes each with a plurality of digraph links. The method further comprises selecting a superframe size at least large enough to accommodate the total number of desired digraph links and assigning each desired digraph link to a cell in the superframe wherein each cell in the superframe specifies a synchronized time and frequency communication plan.

Abstract: In a packet communication network, a method and apparatus for packet switched transport is provided among intelligent nodes wherein the duty cycling of the intelligent nodes is minimized in order to maximize power life using a synchronization algorithm that assures all nodes are able to propagate information through the network without undue use of transmission and reception power. Frequency hopping time-division multiple access supports packet communication between intelligent nodes via assigned directed links, each link being assigned to a time-channel offset (cell) in a superframe, so that a link carrying a packet string between any two intelligent nodes is active only during its assigned time slot. The result is efficient use of spectrum and minimal expenditure of power.

Abstract: A method of assigning cells in a superframe using digraph link information in a network of nodes is disclosed. The method comprises determining a total number of desired digraph links in the network of nodes wherein a digraph link is a directional link specifying routing information at each node in the network between said node and a second node, and wherein the network of nodes includes a plurality of nodes each with a plurality of digraph links. The method further comprises selecting a superframe size at least large enough to accommodate the total number of desired digraph links and assigning each desired digraph link to a cell in the superframe wherein each cell in the superframe specifies a synchronized time and frequency communication plan.

Abstract: A method of assigning cells in a superframe using digraph link information in a network of nodes is disclosed. The method comprises determining a total number of desired digraph links in the network of nodes wherein a digraph link is a directional link specifying routing information at each node in the network between said node and a second node, and wherein the network of nodes includes a plurality of nodes each with a plurality of digraph links. The method further comprises selecting a superframe size at least large enough to accommodate the total number of desired digraph links and assigning each desired digraph link to a cell in the superframe wherein each cell in the superframe specifies a synchronized time and frequency communication plan.

Abstract: What is described in the present specification are accelerometers using tiny proof masses and piezoresistive force detection. Conventional wisdom would indicate that this approach would not yield useful sensors. However, in fact, according to the invention, such devices are suitable in a wide range of applications. The devices may include deformable hinges to allow the fabrication of three dimensional structures. A new system has been developed which etches silicon highly selectively at moderate temperatures and without hydrodynamic forces potentially damaging to small structures and features. The system is based on the use of the gas phase etchant xenon diflouride, which is an unremarkable white solid at standard temperature and pressure.

Abstract: Improved microsensors are provided by combining surface micromachined substrates, including integrated CMOS circuitry, together with bulk micromachined wafer bonded substrates which include at least part of a microelectromechanical sensing element. In the case of an accelerometer, the proof mass is included within the wafer bonded bulk machined substrate, which is bonded to the CMOS surface machine substrate, which has corresponding etch pits defined therein over which the wafer bonded substrate is disposed, and in the case of accelerometer, the proof mass or thin film membranes in the case of other types of detectors such as acoustical detectors or infrared detectors. A differential sensor electrode is suspended over the etch pits so that the parasitic capacitance of the substrate is removed from the capacitance sensor, or in the case of a infrared sensor, to provide a low thermal conductance cavity under the pyroelectric refractory thin film.