Helen L Davis

US Patent:

6486861, Nov 26, 2002

Filed:

May 7, 1999

Appl. No.:

09/306752

Inventors:

Bryan T. Preas - Palo Alto CA
Helen M. Davis - Cupertino CA

Assignee:

Xerox Corporation - Stamford CT

International Classification:

G09G 336

US Classification:

345 87, 345 40, 345107, 345629, 345641, 359295, 359296, 428195

Abstract:

A method to greatly simplify and reduce the cost of displays when all of the images that need to be displayed are known beforehand. By precomputing the intersections of the images and addressing the intersections of the images, the number of drivers that are required becomes a function of the number of images rather than a function of the resolution. For example, four arbitrarily complex, overlapping images require, at most, 16 drivers. In general, n arbitrarily complex, overlapping images require, at most, 2 drivers. This result holds irrespective of the size of the display or the complexity resolution, or amount of overlap of the images. Further reduction of the number of drivers is possible if some of the images do not overlap some of the other images. For example, two images overlap each other in one area and two other images may overlap each other in a separate area while the two sets of images do not themselves overlap. In this case, at most eight drivers are needed instead of the 16 drivers that would be required if all four of the images overlapped each other.

US Patent:

20040056853, Mar 25, 2004

Filed:

Mar 25, 2003

Appl. No.:

10/396119

Inventors:

Bryan Preas - Palo Alto CA, US
Helen Davis - Cupertino CA, US
Franklin Vest - Santa Clara CA, US
Russel Martin - Menlo Park CA, US

International Classification:

G09G005/00

US Classification:

345/204000

Abstract:

An electronically controllable/programmable sign comprises a multi-layer display device, a display driver for applying at least one field across the image layer in accordance with a display signal, and a controller for providing the display signal to the display driver. The multilayer display device includes at least one image layer. The image layer has one or more regions of reflective media whose reflectivity changes in response to an applied fields. An electronically conductive layer is positioned on one side of the image layer; and a counterelectrode layer is positioned on the other side of the image layer.

US Patent:

58354913, Nov 10, 1998

Filed:

Nov 21, 1996

Appl. No.:

8/754726

Inventors:

Helen M. Davis - Palo Alto CA
Bryan T. Preas - Palo Alto CA
Alan G. Bell - Palo Alto CA
Joseph B. Lyles - Mountain View CA
Daniel H. Greene - Sunnyvale CA

Assignee:

Xerox Corporation - Stamford CT

International Classification:

H04L 1256

US Classification:

370386

Abstract:

A method controls multicast cell access to a switching network with a reservation ring in an ATM (Asynchronous Transfer Mode) switch. The switching network distributes the multicast cell in one or more passes from an input channel to one or more output channels of the switch during a switch cycle. An arbitration session for a multicast cell begins by submitting an arbitration request identifying a set of destination output channels to the reservation ring. During an arbitration cycle, the output channels in the set of destination output channels are arbitrated for over the reservation ring. The arbitration request is reissued during later arbitration cycles until access to each of the destination output channels in the set of output channels is granted.

US Patent:

59128895, Jun 15, 1999

Filed:

Nov 21, 1996

Appl. No.:

8/754727

Inventors:

Bryan T. Preas - Palo Alto CA
Helen M. Davis - Palo Alto CA
Alan G. Bell - Palo Alto CA
Joseph B. Lyles - Mountain View CA

Assignee:

Xerox Corporation - Stamford CT

International Classification:

H04L 1256

US Classification:

370359

Abstract:

Ports of an ATM (Asynchronous Transfer Mode) switch are consolidated into cluster modules to increase the aggregate throughput of the switch. Packets are routed between cluster modules using an intercluster switching network. The intercluster switching network includes a plurality of input channels and output channels. During a switch cycle, a maximum of "K" packets are delivered to each of the output channels of the intercluster switching network. This maximum of "K" packets is a speedup per cluster module that is shared between ports of each cluster module. Consequently, each output port of a cluster module operates with a peak speedup of up to "K" packets per switch cycle thereby increasing the aggregate throughput of the switch.

US Patent:

59497890, Sep 7, 1999

Filed:

Nov 21, 1996

Appl. No.:

8/754734

Inventors:

Helen M. Davis - Palo Alto CA
Bryan T. Preas - Palo Alto CA
Alan G. Bell - Palo Alto CA
Joseph B. Lyles - Mountain View CA
Daniel H. Greene - Sunnyvale CA

Assignee:

Xerox Corporation - Stamford CT

International Classification:

H04J 302

US Classification:

370452

Abstract:

Access to a limited bandwidth switching network of an ATM (Asynchronous Transfer Mode) switch is scheduled using a reservation ring. In general, a limited bandwidth switching network is unable to generate all possible one-to-one input to output channel mappings in a single switch cycle. The limited bandwidth switching network includes one or more routing channels for routing at most B data packets each switch cycle between the input channels and output channels, where the number of data packets B is less than the aggregate output bandwidth that can be directed at the routing channels. Arbitration requests make two passes around the reservation ring each arbitration cycle. Output channel contention is settled during the first pass around the reservation ring. Contention for limited switching network bandwidth is settled during the second pass around the reservation ring. Arbitration requests granted a reservation at the end of an arbitration cycle are issued into the limited bandwidth switching network during a subsequent switch cycle.

US Patent:

58838953, Mar 16, 1999

Filed:

Nov 21, 1996

Appl. No.:

8/754688

Inventors:

Helen M. Davis - Palo Alto CA
Daniel H. Greene - Sunnyvale CA
Alan G. Bell - Palo Alto CA

Assignee:

Xerox Corporation - Stamford CT

International Classification:

H04L 12403
H04J 302

US Classification:

370462

Abstract:

Access to a switching network of an ATM (Asynchronous Transfer Mode) switch is scheduled with a reservation ring that automatically determines the number of channels populating the switching network during a switch cycle. The reservation ring is a distributed arbiter that resolves conflicts arising among a plurality of input channels for access to a plurality of output channels of the switching network. Each input channel populating the switching network is coupled to an arbitration unit of the reservation ring. The arbitration units on the ring determine when an arbitration cycle is complete for each of the arbitration units populating the ring. This enables the number of channels populating the switching network to increase or decrease without having to reconfigure the reservation ring.