A technique for streaming digital video content to a client involves providing a new stream of digital video content to the client using forward error correction (FEC) for a limited initial period and then ending the use of FEC after the limited initial period has ended. In an embodiment, during the limited initial period, the digital video content is provided to the client at a rate that is slightly higher than the playout rate in order to allow a client buffer to accumulate digital video content. FEC continues to be used until the client buffer is sufficiently populated such that lost or damaged frames can be retransmitted to the client before the corresponding digital video content is needed for playout. Once the client buffer is sufficiently populated, FEC is ended and retransmission is used to maintain the quality of the streamed digital video content.

Method and system for streaming digital video content to a client in a digital video network

In accordance with one embodiment of the present invention, a Gap Diode is disclosed in which a tubular actuating element serves as both a housing for a pair of electrodes (92) and as a means for controlling the separation between the electrode pair. In a preferred embodiment, the tubular actuating element (90) is a quartz piezo-electric tube. In accordance with another embodiment of the present invention, a Gap Diode is disclosed which is fabricated by micromachining techniques in which the separation of the electrodes (202, 206) is controlled by piezo-electric, electrostrictive or magnetostrictive actuators. Preferred embodiments of Gap Diodes include Cool Chips, Power Chips, and photoelectric converters.

Thermionic vacuum diode device with adjustable electrodes

In a digital video network that is capable of distributing digital video content to a client via multicasting and unicasting, servicing a channel change request from a client involves switching from providing the digital video content to the client via multicasting to providing the digital video content to the client via unicasting and continuing to provide digital video content to the client via unicasting until a pre- established condition is met. Continuing to provide digital video content to the client via unicasting until a pre-established condition is met allows the network to opportunistically switch the client from unicasting back to multicasting.

Fast channel change with conditional return to multicasting

Towards Optimization of Automotive Waste Heat Recovery Using Thermoelectrics

A solar powered electricity generating system comprised of a concentrator assembly that concentrates solar flux into a thermal storage unit. The thermal storage unit converts solar energy into heat energy which is then provided to three cascaded converter stages which, in the preferred embodiment, are comprised of a thermionic electric converter (TEC), an alkaline metal thermal to electric converter (AMTEC) and a thermoelectric generator stage comprised of a plurality of thermal photovoltaic cells. A phase change material is positioned within the thermal receiver such that the solar flux converts the material from a solid phase into a liquid phase such that the thermal storage unit can continue to generate heat energy when the sun is no longer providing thermal flux to the receiver as a result of the heat energy produced as the phase change material changes back from a liquid phase to a solid phase.

Solar power system using thermal storage and cascaded thermal electric converters

Modern cars use more and more electric power due to more on-board electric systems. A modern car may be equipped with an electric generator (generally an alternator) with an output current of maximum 60-90 A at 12 V. A belt driven generator has a rather low total efficiency and so it is interesting to find alternative solutions for this electricity generation problem. One possible energy source for electricity generation is to use the waste heat from the car's engine, which generally is as much as much as 80% of the total energy from the combustion of the gasoline. Maybe the best location to tap the excess heat is the catalytic converter (Cat) in the exhaust system or perhaps at the exhaust pipes close to the engine. The Cat must be kept within a certain temperature interval. Large amounts of heat are dissipated through the walls of the Cat. A thermionic energy converter (TEC) in a coaxial form could conveniently be located around the ceramic cartridge of the Cat. Since the TEC is a rather good heat insulator before it reaches its working temperature, the Cat will reach working temperature faster and its final temperature can be controlled better when encapsulated in a concentric TEC arrangement. It is also possible to regulate the temperature of the Cat and the TEC by controlling the electrical load of the TEC. The possible working temperatures of present and future Cats appear very suitable for the authors' new low work function collector TEC, which has been demonstrated to work down to 470 K.

L. Holmlid

Papers

TEC as electric generator in an automobile catalytic converter