12274results about "Generating/distributing signals" patented technology

A peer-to-peer protocol is based on the use of global timestamps and client priorities in serializing modifications to a shared workspace of real-time collaboration. The method caters to dynamic clients wherein a client can leave or join an ongoing collaboration session as long as there is always at least one client present / remaining in the collaboration session. The method can support multiple definitions of a modification, including partitioning-based definitions, wherein the method provides full support for locking of partitions, and a full treatment of inter-partition synchronization via a modification definition over multiple partitions. The method is capable of utilizing the many standard methods of creating a global, distributed, synchronized clock for the global timestamps utilized by it. The method is rollback-based for correcting tentative but incorrect serializations, and provides additional backup in terms of checkpoints for additional safety and for the support of lightweight, pervasive clients. The method includes many optimizations for efficiency, and includes a method of switching to and back from distributed server-based serialization for the periods when the network response is better suited to a distributed server than the peer-to-peer protocol.

Nodes in a network include a pseudo-timestamp in messages or packets, derived from local pseudo-time clocks. When a packet is received, a first time is determined representing when the packet was sent and a second time is determined representing when the packet was received. If the difference between the second time and the first time is greater than a predetermined amount, the packet is considered to be stale and is rejected, thereby deterring replay. Because each node maintains its own clock and time, to keep the clocks relatively synchronized, if a time associated with a timestamp of a received packet is later than a certain amount with respect to the time at the receiver, the receiver's clock is set ahead by an amount that expected to synchronize the receiver's and the sender's clocks. However, a receiver never sets its clock back, to deter attacks.

An interval centroid-based watermark encoder encodes a watermark into a packet flow. Intervals are defined for the packet flow. Some of the intervals are selected as group A intervals while other intervals are selected as group B intervals. Group A and group B intervals are paired and assigned to watermark bits. A first or second value may be encoded by increasing the relative packet time between packets in either the group A (for the first bit value) or group B (for the second bit value) interval(s) of the interval pair(s) assigned to the watermark bits that are to represent the first or second bit value and the beginning of the same group interval(s). The relative packet times may be measured by a decoder and used to calculate a centroid difference for each interval pair. The centroid differences may be used to reconstruct the watermark.

A system and method for synchronizing devices which can couple to the Internet, or any network. In one aspect a system for synchronizing data between a first system and a second system is provided. The system includes a first sync engine on the first system interfacing with data on the first system to provide difference information. A data store is coupled to network and in communication with the first and second systems. A second sync engine is provided on the second system coupled to receive the difference information from the data store via the network, and interfacing with data on the second system to update said data on the second system with said difference information. Difference information is transmitted to the data store by the first sync engine and received from the data store from the second sync engine. The system may include a management server coupled to the network and in communication with the first sync engine, the second sync engine and the data store. The system may include a plurality of sync engines on a respective plurality of systems, each of said plurality of engines being coupled to receive difference information from each of said first, second and plurality of sync engines from the data store via the network. Each said engine interfaces with data on the system on which it resides to update said data on said system on which it resides with said difference information, and interfaces with data on said system on which it resides to provide difference data information from the system on which it resides to the data store. In a further embodiment, the invention comprises a method for synchronizing at least a first file and a second file resident on a first and a second systems, respectively, coupled to the Internet, respectively. The method includes the steps of: determining difference data resulting from changes to the first file on the first system; transmitting the difference data to a server via the Internet; querying the server from a second system to determine whether difference data exists for files on the second system; retrieving the difference data to the second system; and updating the second file on the second system with the difference data.