Xerox Corporation

Michael J Spreitzer

Marvin Michael Theimer

Roy Want

William Noah Schilit

Douglas Brian Terry

Mark D Weiser

Richard J Goldstein

Alan J Demers

Karin Petersen

Daniel C Swinehart

Brent B Welch

Scott Alan Elrod

Robert Thomas Krivacic

The present invention describes a system of multiple devices and multiple users, wherein the identity and location of each device and user may be known to the system. A method is described for establishing media connections between at least a first user and a second user based on the context of the system and the environment of the particular device, computing devices, or users. The system receives a media connection request from the first user, including information indicating the first user preferences for media, and identifies the intended recipient user or users. The location and media devices in proximity to each of the users is determined, and the preset profiles and policies of the users involved are determined. Each user may specify acceptable media connections and contextual attributes. When the contextual attributes and acceptable media connections for each user are consistent, media device communications paths are established.

Specifying and establishing communication data paths between particular

Write operations for weakly consistent replicated database systems have application-specific embedded dependency queries and related descriptions of the results that are expected to be returned when the respective dependency queries are run against the database. The dependency queries are arbitrary queries that are provided by the application to satisfy the requirements of the application. Write operations that conflict with the current state of any given instance of such a database are detected by comparing (a) the results that are returned when the dependency queries for those writes are run against the given instance of the database with (b) the results that are expected to be returned.

Application-specific conflict detection for weakly consistent replicated

The present invention describes a method for superimposing prespecified locational, environmental, and contextual controls on user interactions, including interactions of mobile users, with computational resources. A system is described for electronically monitoring contextual information concerning users and machines, including state and locational information including proximity. Interaction policies, including user specified interaction policies, may be registered on an identifiable address path. Methods are described for detecting, selecting and controlling computercontrolled devices, based on the proximity of the device to the user, the current context of the user, the location of other nearby users and devices, and the current state of the devices. Temporary transfer of control, including exclusive control, of particular computers and computer controlled devices to individual users based on the context and environment in proximity to those computing devices is also described.

Method for selectively performing event on computer controlled device

Write operations for weakly consistent replicated database systems have embedded application-specific merge procedures that are invoked for resolving conflicts whenever it is found that the related write operation conflicts with the current state of a given instance of such a database. The effect of executing such a merge procedure is deterministic for any state of the given instance of the database happens to be in when the merge procedure is executed.

Application-specific conflict resolution for weakly consistent

Method for triggering selected machine event when the triggering

The present invention provides client-selected consistency guarantees to clients of a weakly consistent replicated database on a per 'session' basis. The clients have access to utilities which allow the clients to, individually or collectively, define a 'session' over which the selected guarantees are enforced. A 'session' is broadly defined as a sequence of logically related Reads and Writes to the database. Sessions are initiated and terminated substantially independently of other sessions which may exist concurrently. Clients are allowed, however, to clone sessions and/or merge sessions with other clients. Clients select a minimum relevant subset of guarantees from among a set of pre-defined consistency guarantees, where 'relevancy' is a client determined factor. At any given time, the system may be enforcing a number of different combinations of consistency guarantees. The guarantees ensure that all clients participating in a particular session view the database as having certain conditions of data consistency--the consistency of which is only provided with respect to the participants' Read and Write requests. Clients are allowed to downgrade their selected guarantees during the course of their sessions. One implementation of the present invention permits the selection of any one of four consistency guarantees.

Method for providing session consistency guarantees

Write operations for weakly consistent replicated database systems have embedded conflict detection and conflict resolution procedures for identifying and resolving, respectively conflicts between such write operations and the current state of any given instance of such a database. These write operations are committed to a firm execution order by the host for one instance of such a database, and this execution order propagates to the other instances of the database. Accordingly, a write log distinguishes between the writes that are known to be committed to a firm execution order (the 'tentative writes') is maintained for each instance of the database, thereby enabling the user to explicitly identifying the stable data and the potentially unstable data in any given instance of the database. Furthermore, provision is made for enabling users to select from a set of predefined consistency guarantees across all instances of such a database for any given session.

Methodology for managing weakly consistent replicated databases

A write log that distinguishes between write operations that are known to be in a stable write order ('committed writes') and write operations that still are in a potentially unstable write order ('tentative writes') are maintained for each instance of a weakly consistent replicated database so that the stable and the potentially unstable data in any given instance of such a database can be explicitly identified.

Identification of stable writes in weakly consistent replicated

Method for granting a user request having locational and contextual

System for granting ownership of device by user based on requested level

The present invention describes a method for selectively delivering electronic messages to an identified user or users in a system of mobile and fixed devices, including multiple display devices and multiple users, based on the context of the system and the environment of the identified user. Electronic messages intended for an identified user or users may be given a level of privacy and a level priority, and contextual attributes for its delivery may be specified. The system perceives contextual attributes for the recipient user or users, including display devices in close proximity to the identified users, and determines a display property for said electronic message based on the contextual attributes, the user profile properties of each user, and the level of privacy and level of priority of the electronic message. The display property may designate immediate delivery on a particular display device, a notification on a particular display device, or storage of the message until the contextual attributes of the recipient user is consistent with the specified contextual attributes of the electronic message.

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Tracy, CA, United States of America

Michael J Spreitzer