Abstract: A network construction method, a routing method and device of mobile ad-hoc networks are provided. The mobile ad-hoc network includes a plurality of nodes, each node communicating with its neighbors via communication links. The routing method comprises the following steps: each node identifying a link quality with each of its neighbors by providing marks based on a hysteresis-based link quality marking mechanism; each node identifying a link operationality with each of its neighbors by evaluating a score calculated from the marks; and each node reconstructing routes with its neighbors by filtering route construction messages related to the link operationality of the neighbors.

Abstract: A network construction method, a routing method and device of mobile ad-hoc networks are provided. The mobile ad-hoc network includes a plurality of nodes, each node communicating with its neighbors via communication links. The routing method comprises the following steps: each node identifying a link quality with each of its neighbors by providing marks based on a hysteresis-based link quality marking mechanism; each node identifying a link operationality with each of its neighbors by evaluating a score calculated from the marks; and each node reconstructing routes with its neighbors by filtering route construction messages related to the link operationality of the neighbors.

Abstract: A network construction method, a routing method and device of mobile ad-hoc networks are provided. The mobile ad-hoc network includes a plurality of nodes, each node communicating with its neighbors via communication links. The routing method comprises the following steps: each node identifying a link quality with each of its neighbors by providing marks based on a hysteresis-based link quality marking mechanism; each node identifying a link operationality with each of its neighbors by evaluating a score calculated from the marks; and each node reconstructing routes with its neighbors by filtering route construction messages related to the link operationality of the neighbors.

Abstract: A network construction method, a routing method and device of mobile ad-hoc networks are provided. The mobile ad-hoc network includes a plurality of nodes, each node communicating with its neighbors via communication links. The routing method comprises the following steps: each node identifying a link quality with each of its neighbors by providing marks based on a hysteresis-based link quality marking mechanism; each node identifying a link operationality with each of its neighbors by evaluating a score calculated from the marks; and each node reconstructing routes with its neighbors by filtering route construction messages related to the link operationality of the neighbors.

Abstract: The present invention relates generally to the field of wireless communication and, in particular, to the field of reducing shadowing and multipath fading over a wireless link. According to a broad aspect of this invention, there is provided a novel design of a passive reflector repeater and a set of methods to be used to configure a set of reflector repeaters to bend RF waves around obstacles along the direct path of a wireless link.

Abstract: A method of collecting data from wireless sensor units arranged in a network. The method may comprise the steps of initiating distribution of control signals to the wireless sensor units, acquiring data with the wireless sensor units by sensing one or more physical parameters, each of the wireless sensor units transmitting the acquired data in response to the control signals; and each of the wireless sensor units transmitting of at least a portion of the acquired data according to a prioritizing algorithm associated with each respective wireless sensor unit.

Abstract: System and method for retrieving data from distributed nodes using radio. Data is transmitted through a mesh of nodes to aggregators, and may be transmitted through a mesh of aggregators to higher level aggregators. High level aggregators are arranged in pipelines and configured to transmit and receive simultaneously to maximize information relaying capacity.

Abstract: A wireless network is provided, that may comprise wireless sensor units organized in chains of wireless sensor units. Each wireless sensor unit may comprise plural sensors and at least a wireless transceiver connected to communicate by wires or wirelessly with the plural sensors. Each chain of wireless sensor units may include a terminal wireless sensor unit and intermediate wireless sensor units, each intermediate wireless sensor unit being configured to relay data along the chain of intermediate wireless sensor units towards the terminal wireless sensor unit. The terminal wireless sensor unit in each chain of wireless sensor units is adapted to communicate wirelessly with at least one backhaul unit of plural backhaul units; and the backhaul units are adapted to communicate with a central computer.

Abstract: A method of collecting data from wireless sensor units arranged in a network. The method may comprise the steps of initiating distribution of control signals to the wireless sensor units, acquiring data with the wireless sensor units by sensing one or more physical parameters, each of the wireless sensor units transmitting the acquired data in response to the control signals; and each of the wireless sensor units transmitting of at least a portion of the acquired data according to a prioritizing algorithm associated with each respective wireless sensor unit.

Abstract: A wireless network is provided, that may comprise wireless sensor units organized in chains of wireless sensor units. Each wireless sensor unit may comprise plural sensors and at least a wireless transceiver connected to communicate by wires or wirelessly with the plural sensors. Each chain of wireless sensor units may include a terminal wireless sensor unit and intermediate wireless sensor units, each intermediate wireless sensor unit being configured to relay data along the chain of intermediate wireless sensor units towards the terminal wireless sensor unit. The terminal wireless sensor unit in each chain of wireless sensor units is adapted to communicate wirelessly with at least one backhaul unit of plural backhaul units; and the backhaul units are adapted to communicate with a central computer.

Abstract: A low noise imaging apparatus for producing Magnetic Resonance (MR) images of a subject and for substantially minimizing acoustic noise generated during imaging is provided. The imaging apparatus comprises a magnet assembly, a gradient coil assembly, and a rf coil assembly, wherein at least one of the magnet assembly, the gradient coil assembly and the rf coil assembly are configured to reduce the generation and transmission of acoustic noise.

Abstract: A quadrature coil suitable for use with an open frame MRI system provides crossing pairs of arrays of parallel conductor elements, respectively. Compact configuration is provided through use of an isolating circuit for incorporating parasitic capacitances at the resonance frequency of the coil into a blocking parallel resonance. Termination of the parallel conductor elements may be accomplished by equal impedance node connectors formed from branching pairs of conductors or a triangular least resistance connection form. RF shields are provided by pairs of conductive sheets containing eddy current reducing slots aligned with the parallel conductors elements of the coil.

Abstract: An MR magnet assembly includes a cylindrical vessel for housing a superconducting magnet and having a vacuum between its inner and outer walls. The vessel defines a magnet bore for receiving a patient to be imaged. A gradient coil assembly is mounted in the bore adjacent the inner wall of the magnet assembly. To reduce gradient coil noise, the inner wall is constructed of a non-conductive material which does not support eddy currents.

Abstract: An amalgam is accurately placed and retained in an optimized location in the exhaust tube of an electrodeless SEF lamp for operation at a mercury vapor pressure in the optimum range from approximately four to seven millitorr by forming a dimple in the exhaust tube and using a dose locating member to locate and retain the amalgam on the side of the dimple away from the core of the lamp after filling the lamp. As an alternative, two dimples may be situated on opposite sides of the exhaust tube for performing the same function as, but with less depth than, the single dimple. In another alternative embodiment, first and second dimple configurations are formed in the exhaust tube after tip-off thereof, each dimple configuration including either one or two dimples. The second dimple configuration is spaced apart from the first dimple configuration along the length of the exhaust tube.

Abstract: An electrically controllable variable capacitor includes the interelectrode capacitance of at least one power MOSFET, a capacitance connected in series with the MOSFET and having one terminal connected to the drain or source thereof (the series capacitance), and bias control circuitry for controlling the bias voltage applied to the MOSFET. The voltage rating of the MOSFET, the peak amplitude of the applied ac signal, and the value of the series capacitance determine the range of dc bias voltages over which the MOSFET can be operated, and hence the capacitance range of the variable capacitor. Such a variable capacitance is useful as a tuning capacitor in an electrodeless HID lamp ballast.

Abstract: Power semiconductor device structures and assemblies with improved heat dissipation characteristics and low impedance interconnections include a thermally-conductive dielectric layer, such as diamondlike carbon (DLC) overlying at least portions of the active major surface of a semiconductor chip, with vias formed in the dielectric layer in alignment with contact pads on the active major surface. A patterned metallization layer is formed over the thermally-conductive dielectric layer, with portions of the metallization layer extending through the vias into electrical contact with the chip contact pads. A metal structure is electrically and thermally coupled to selected areas of the patterned metallization, such as by solder bonding or by a eutectic bonding process. In different embodiments, the metal structure may comprise a metal conductor bonded to the opposite major surface of another power semiconductor device structure, a heat-dissipating device-mounting structure, or simply a low-impedance lead.

Abstract: A modified valley fill circuit, including a main ballasting inductor for supplying an electrolytic capacitor, has an additional charging winding on the main ballasting inductor for charging the electrolytic capacitor to a predetermined voltage which maximizes the power factor of the input current by optimizing the conduction angle of the input current. In a discharge lamp ballast, the modified valley fill circuit reduces the lamp current crest factor by controlling the frequency with a lamp current control loop.

Abstract: A multi-resonant boost power factor correction circuit includes a full-wave rectifier; a high frequency filter capacitance coupled across the input terminals of the full-wave rectifier; a series half-bridge converter; a diode connected between the output of the rectifier and the dc bus voltage such that its cathode is connected to a dc bus; a capacitance coupled between the output of the rectifier and the junction between the series-connected switching devices of the half-bridge converter; a resonant load circuit connected to the junction between the switching devices, including a resonant inductor, a resonant capacitor and a load, such as a fluorescent discharge lamp; and a driver circuit for alternately switching the switching devices via a dead time control for selecting a dead time after one of the devices switches off and the other device switches on.

Abstract: A fixed duty ratio, variable frequency, square wave generator includes an astable multivibrator having a pair of resistors coupled in series between a supply voltage terminal and a capacitor, such as of a type implemented with a 555 timer, and further includes a JFET connected between the capacitor and ground. In a current-controlled version, the anode of a diode is connected to the gate of the JFET, and the cathode of the diode is connected to a sensing resistor for sensing current in a load. The multivibrator generates a ramp voltage across the capacitor which varies between predetermined fractions of the supply voltage with a fixed duty ratio. The capacitor of the multivibrator charges and discharges through the series connection of the resistors and the JFET channel resistance with charging and discharging times that vary with the input voltage to the JFET, thereby varying the generator frequency.

Abstract: A simulated load circuit for measuring the impedance of the arc discharge of an electrodeless discharge lamp of the type having an arc tube and an excitation coil for exciting the arc discharge in an ionizable fill contained therein includes: a secondary coil spaced apart from the excitation coil by a distance which is varied in order to vary the coupling coefficient between the secondary coil and the excitation coil; a fixed load resistance coupled to the secondary coil; and a variable matching network coupled in series or parallel with the load resistance, the impedance of the matching network being varied in order to vary the ratio of reactance to resistance of the load circuit. The distance between the secondary coil and the excitation coil is varied, and the impedance of the matching network is varied, until the input impedance of the load circuit is substantially equivalent to the operating impedance of the lamp.