Abstract: Methods and apparatus, including computer systems and program products, related to techniques for creating a chain of transfer for a digital document in which every transferor and transferee participates in the transfer. A first entity, e.g., an offeror with current control of the document, generates an offeror certificate associated with the digital document, and encrypts the offeror certificate with the offeror's private key. The offeror transmits the encrypted offeror certificate to a second entity, e.g., an offeree that will be the subsequent controller of the document. The offeree generates an offeree certificate from the offeror certificate, encrypts the offeree certificate with the offeree's private key, and transmits the encrypted offeree certificate to the offeror. When the offeror receives the offeree certificate, the offeror adds the offeree to a chain of transfer for the document and generates a transfer certificate for the offeree.

Abstract: The present invention comprises a system for delivering an interactive multimedia work from a storage device, for example a hard disk drive, a CD-ROM drive, a network server, etc. to a playback device, for example a personal computer, in a manner that provides improved performance regardless of the playback sequence selected by a user. In one embodiment of the present invention, for each segment of an interactive multimedia work, a probability factor is assigned to each possible alternative succeeding segment. In addition a retrieval and delivery time cost factor is also assigned to each possible succeeding segment. In one embodiment of the invention, the time cost factor for each resource is assigned a fixed value. In another embodiment, the time cost factor is recalculated periodically to reflect changes in location and status of resources. The probability and time cost factor for each possible succeeding segment are combined to produce a relative priority ranking.

Abstract: The present invention comprises a system for delivering an interactive multimedia work from a storage device, for example a hard disk drive, a CD-ROM drive, a network server, etc. to a playback device, for example a personal computer, in a manner that provides improved performance regardless of the playback sequence selected by a user. In one embodiment of the present invention, for each segment of an interactive multimedia work, a probability factor is assigned to each possible alternative succeeding segment. In addition a retrieval and delivery time cost factor is also assigned to each possible succeeding segment. In one embodiment of the invention, the time cost factor for each resource is assigned a fixed value. In another embodiment, the time cost factor is recalculated periodically to reflect changes in location and status of resources. The probability and time cost factor for each possible succeeding segment are combined to produce a relative priority ranking.

Abstract: A method and apparatus for generating bipolar pulses in a local area network is disclosed comprising a transmitter. In the transmitter there is provided a pair of transistors which are coupled together in a resistor network. A capacitor is provided for coupling the transistors and resistor network to a transmission line. In operation, the output impedance of the transmitter is low when either of the transistors is conducting and high when neither of the transistors is conducting. To generate Alternate Mark Inversion pulses, both transistors are turned on. Thereafter, and in response to a signal corresponding to a logical 1, one of the transistors is turned off and then turned on for generating a positive pulse on the transmission line. Upon the occurrence of a subsequent control signal corresponding to the next logical 1, the other of the transistors is turned off and then on for producing a negative pulse on the transmission line.

Abstract: In a data communications systems having a communications channel (3) for interconnecting a plurality of transceivers (1) and (2), each of said transceivers (1) and (2) including means (80) for transmitting a signal having transitions, there is provided a means (20) responsive to the presence and absence of a signal on said communications channel (3) during a transition of a signal transmitted by said transmitting means (80) for providing a collision detected (CD) signal if there is destructive interference with the transmitted signal on said communication channel (3) during a transition of said transmitted signal and means (48) responsive to said CD signal for terminating said transmitting of said signal.