Abstract: A system for restricting operation of wireless devices, for example cell phones, comprises a controller and a plurality of sensors. The system restricts device usage, while permitting emergency phone calls, for example 911 calls. The sensors receive transmissions from devices, and use the transmissions for identification and determining whether a device is within a restricted zone. One disclosed method is triangulation, using time of arrival of transmissions at the sensors. If the device is within the zone, the controller sends device identification, and possibly a customized restriction request, to a remote node, for example a control node of a cell phone network operator. The operator then uses its network resources to implement the requested restrictions. Communication between the controller and the remote node is secure, possibly encrypted, to minimize malicious interference. A wireless control can define vertices of the zone and exempt certain devices from restrictions. Jamming is not required.

Abstract: A system for restricting operation of wireless devices, for example cell phones, comprises a controller and a plurality of sensors. The system restricts device usage, while permitting emergency phone calls, for example 911 calls. The sensors receive transmissions from devices, and use the transmissions for identification and determining whether a device is within a restricted zone. One disclosed method is triangulation, using time of arrival of transmissions at the sensors. If the device is within the zone, the controller sends device identification, and possibly a customized restriction request, to a remote node, for example a control node of a cell phone network operator. The operator then uses its network resources to implement the requested restrictions. Communication between the controller and the remote node is secure, possibly encrypted, to minimize malicious interference. A wireless control can define vertices of the zone and exempt certain devices from restrictions. Jamming is not required.

Abstract: A system for restricting operation of wireless devices, for example cell phones, comprises a controller and a plurality of sensors. The system restricts device usage, while permitting emergency phone calls, for example 911 calls. The sensors receive transmissions from devices, and use the transmissions for identification and determining whether a device is within a restricted zone. One disclosed method is triangulation, using time of arrival of transmissions at the sensors. If the device is within the zone, the controller sends device identification, and possibly a customized restriction request, to a remote node, for example a control node of a cell phone network operator. The operator then uses its network resources to implement the requested restrictions. Communication between the controller and the remote node is secure, possibly encrypted, to minimize malicious interference. A wireless control can define vertices of the zone and exempt certain devices from restrictions. Jamming is not required.

Abstract: A system for restricting operation of wireless devices, for example cell phones, comprises a controller and a plurality of sensors. The system restricts device usage, while permitting emergency phone calls, for example 911 calls. The sensors receive transmissions from devices, and use the transmissions for identification and determining whether a device is within a restricted zone. One disclosed method is triangulation, using time of arrival of transmissions at the sensors. If the device is within the zone, the controller sends device identification, and possibly a customized restriction request, to a remote node, for example a control node of a cell phone network operator. The operator then uses its network resources to implement the requested restrictions. Communication between the controller and the remote node is secure, possibly encrypted, to minimize malicious interference. A wireless control can define vertices of the zone and exempt certain devices from restrictions. Jamming is not required.

Abstract: A system for restricting operation of wireless devices, for example cell phones, comprises a controller and a plurality of sensors. The system restricts device usage, while permitting emergency phone calls, for example 911 calls. The sensors receive transmissions from devices, and use the transmissions for identification and determining whether a device is within a restricted zone. One disclosed method is triangulation, using time of arrival of transmissions at the sensors. If the device is within the zone, the controller sends device identification, and possibly a customized restriction request, to a remote node, for example a control node of a cell phone network operator. The operator then uses its network resources to implement the requested restrictions. Communication between the controller and the remote node is secure, possibly encrypted, to minimize malicious interference. A wireless control can define vertices of the zone and exempt certain devices from restrictions. Jamming is not required.

Abstract: A system for restricting operation of wireless devices, for example cell phones, comprises a controller and a plurality of sensors. The system restricts device usage, while permitting emergency phone calls, for example 911 calls. The sensors receive transmissions from devices, and use the transmissions for identification and determining whether a device is within a restricted zone. One disclosed method is triangulation, using time of arrival of transmissions at the sensors. If the device is within the zone, the controller sends device identification, and possibly a customized restriction request, to a remote node, for example a control node of a cell phone network operator. The operator then uses its network resources to implement the requested restrictions. Communication between the controller and the remote node is secure, possibly encrypted, to minimize malicious interference. A wireless control can define vertices of the zone and exempt certain devices from restrictions. Jamming is not required.

Abstract: A system for restricting operation of wireless devices, for example cell phones, comprises a controller and a plurality of sensors. The system restricts device usage, while permitting emergency phone calls, for example 911 calls. The sensors receive transmissions from devices, and use the transmissions for identification and determining whether a device is within a restricted zone. One disclosed method is triangulation, using time of arrival of transmissions at the sensors. If the device is within the zone, the controller sends device identification, and possibly a customized restriction request, to a remote node, for example a control node of a cell phone network operator. The operator then uses its network resources to implement the requested restrictions. Communication between the controller and the remote node is secure, possibly encrypted, to minimize malicious interference. A wireless control can define vertices of the zone and exempt certain devices from restrictions. Jamming is not required.

Abstract: A pixel for use in a visual matrix display including a frame having front and rear surfaces and defining an aperture; a light source oriented in the aperture; a first retroreflective surface borne by the frame and positioned adjacent to the aperture; a flap borne by the front surface and moveable along a given path of travel between a first position wherein the pixel is nonoperational, and the flap is disposed in covering relation relative to the light source, and a second operational position, wherein the flap has a second retroreflective surface which is exposed when the flap is in the second position; an assembly borne by the frame for moving the flap along the given path of travel; and an assembly for energizing the light source when the flap is in one of the given positions along the path of travel.

Abstract: A pixel for use in a visual matrix display including a frame having front and rear surfaces and defining an aperture; a light source oriented in the aperture; a first retroreflective surface borne by the frame and positioned adjacent to the aperture; a flap borne by the front surface and moveable along a given path of travel between a first position wherein the pixel is nonoperational, and the flap is disposed in covering relation relative to the light source, and a second operational position, wherein the flap has a second retroreflective surface which is exposed when the flap is in the second position; an assembly borne by the frame for moving the flap along the given path of travel; and an assembly for energizing the light source when the flap is in one of the given positions along the path of travel.

Abstract: A pixel for use in a visual matrix display including a frame having front and rear surfaces and defining an aperture; a light source oriented in the aperture; a first retroreflective surface borne by the frame and positioned adjacent to the aperture; a flap borne by the front surface and moveable along a given path of travel between a first position wherein the pixel is nonoperational, and the flap is disposed in covering relation relative to the light source, and a second operational position, wherein the flap has a second retroreflective surface which is exposed when the flap is in the second position; means borne by the frame for moving the flap along the given path of travel; and means for energizing the light source when the flap is in one of the given positions along the path of travel.

Abstract: A pixel for use in a visual matrix display including a frame having front and rear surfaces and defining an aperture; a light source oriented in the aperture; a first retroreflective surface borne by the frame and positioned adjacent to the aperture; a flap borne by the front surface and moveable along a given path of travel between a first position wherein the pixel is nonoperational, and the flap is disposed in covering relation relative to the light source, and a second operational position, wherein the flap has a second retroreflective surface which is exposed when the flap is in the second position; an assembly borne by the frame for moving the flap along the given path of travel; and an assembly for energizing the light source when the flap is in one of the given positions along the path of travel.

Abstract: A pixel for use in a visual matrix display including a frame having front and rear surfaces and defining an aperture; a light source oriented in the aperture; a first retroreflective surface borne by the frame and positioned adjacent to the aperture; a flap borne by the front surface and moveable along a given path of travel between a first position wherein the pixel is nonoperational, and the flap is disposed in covering relation relative to the light source, and a second operational position, wherein the flap has a second retroreflective surface which is exposed when the flap is in the second position; means borne by the frame for moving the flap along the given path of travel; and means for energizing the light source when the flap is in one of the given positions along the path of travel.

Abstract: An improved high current low voltage switching regulator power supply in which the major heat producing components of the power modules of the power supply are mounted on a pair of chill plates with a liquid cooled heat exchanger between the plates. The chill plates are electrically isolated from each other and the heat exchanger. One chill plate also serves as the positive power output bus and the other as the negative power output bus of the power supply which significantly reduces the parasitic inductance of the power supply.

Abstract: A fluid cooling system for electronic systems particularly adapted to cool large scale integrated circuit chips mounted on substrates. The system has one or more heat exchangers through which a liquid coolant is circulated. Each heat exchanger has a flexible wall and is mounted so that its flexible wall is in close proximity to a surface of the substrate to be cooled. A low thermal impedance contact is made through the flexible wall of the heat exchanger between the substrate to be cooled and the coolant flowing through the heat exchanger because of the pressure of the coolant in the heat exchanger. The heat exchangers are connected into the cooling system through flexible conduits so that a heat exchanger can readily be moved out of contact with a substrate without disrupting the flow of coolant through the cooling system.

Abstract: A fluid cooling system for electronic systems particularly adapted to cool large scale integrated circuit chips mounted on substrates. The system has one or more heat exchangers through which a liquid coolant is circulated. Each heat exchanger has a flexible wall and is mounted so that its flexible wall is in close proximity to a surface of the substrate to be cooled. A low thermal impedance contact is made through the flexible wall of the heat exchanger between the substrate to be cooled and the coolant flowing through the heat exchanger because of the pressure of the coolant in the heat exchanger. The heat exchangers are connected into the cooling system through flexible conduits so that a heat exchanger can readily be moved out of contact with a substrate without disrupting the flow of coolant through the cooling system.

Abstract: A liquid cooled heat exchanger particularly adapted to cool heat sinks of an electrical power supply for large electronic systems. The heat exchanger has thin flexible walls. Pressure of the coolant within the heat exchanger assures a positive mechanical contact between the heat exchanger and the heat sink, one that can accommodate changes in dimensions of the heat sink or heat exchanger and a lack of planarity of the surfaces of the heat sink without increasing the thermal impedance between the liquid in the heat exchanger and the heat sink. Fluid flow within the heat exchanger is controlled so that heat transfer efficiency between certain areas of the flexible walls and the coolant is maximized, which areas are proximate to the heat sources mounted on the heat sink.