Abstract: A system for trading media space includes a server node which receives requests for media space from buyers and offers of media space from sellers. The server node includes a set of rules for matching one of the requests and one of the offers to form a matched request and offer pair. A delivery system is connected to said server node for facilitating delivery of media content between the buyer and seller of the matched pair.

Abstract: A system for trading media space includes a server node which receives requests for media space from buyers and offers of media space from sellers. The server node includes a set of rules for matching one of the requests and one of the offers to form a matched request and offer pair. A delivery system is connected to said server node for facilitating delivery of media content between the buyer and seller of the matched pair.

Abstract: A system and method for time-stamping and signing a digital document by an authenticating party and returning the signed stamped document to the originator or his designated recipient. Messages may be received by a first “public” machine over a network, by fax, or through input mediums such as diskettes. The clock of the first machine is synchronized with Universal Coordinated Time (UTC) and can be checked for accuracy by anyone on the network. A second “private” machine, not connected to any network, receives the time-stamped message, applies a hashing procedure and provides a signature using a private key. The signed hashed time-stamped message is then returned. A verify procedure is made widely available to check the genuiness of a document by rehashing the document and applying a public key. The result should match the signed time-stamped message returned by the authenticating party.

Abstract: A device and method provide for an accurate output from a unit, such as an oscillator and/or clock providing an output indicative of frequency and/or time. The device includes a processing section having a microprocessor that develops a model characterizing the performance of the device, including establishing predicted accuracy variations, and the model is then used to correct the unit output. An external reference is used to provide a reference input for updating the model, including updating of predicted variations of the unit, by comparison of the reference input with the unit output. The ability of the model to accurately predict the performance of the unit improves as additional updates are carried out, and this allows the interval between the updates to be lengthened and/or the overall accuracy of the device to be improved. The accuracy of the output is thus adaptively optimized in the presence of systematic and random variations.