Data processing: artificial intelligence – Knowledge processing system – Knowledge representation and reasoning technique
Reexamination Certificate
1999-12-27
2003-08-05
Follansbee, John (Department: 2121)
Data processing: artificial intelligence
Knowledge processing system
Knowledge representation and reasoning technique
C706S045000, C706S046000
Reexamination Certificate
active
06604093
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to computer systems and software, and specifically to tools and methods for programming the reaction of a computer system to specified events and conditions.
BACKGROUND OF THE INVENTION
Reactive systems is a term that is used generally to refer to computer applications that detect, evaluate and respond to events. Such events may include substantially any occurrence of interest that is detected by the computer, such as a change in the price of a stock, the beginning of a banking transaction, change of an entry in a database or a suspected fault in a computer or communication system. The timing, sequence and content of these events are generally not known in advance.
Various tools have been developed in order to allow events and their attendant reactions to be specified in a general, flexible way. Many of these tools are based on Event-Condition-Action (ECA) rules and provide a language of operators for specifying these rules. Some of these languages enable complex events to be defined as the composition of multiple simple events, for example, successive withdrawals from one or more bank accounts. Some languages also allow a complex event to be composed of a number of subsidiary complex events. In addition, a particular order or other timing constraints on the component events may be specified.
Once the complex event has been detected, there may be one or more conditions that qualify the event, for example, that the amounts of the withdrawals be greater than a specified threshold. If the conditions are satisfied, then an action is triggered, such as alerting the bank's security manager of a possible fraud. In the context of the present patent application, a specified composition of events together with the conditions attached to these events is referred to as a situation. Tools for specification of ECA rules generally make a clear separation between the event and condition portions of the rule. Thus when a computer evaluates a given situation on the basis of such tools, it first determines that an instance of the event has occurred, i.e., that all of the component events have occurred in the proper order, and only then evaluates the conditions associated with the event.
Gehani et al., in an article entitled “COMPOSE: A System for Composite Event Specification and Detection,” in Lecture Notes in Computer Science 759 (Springer-Verlag, 1993), pp. 3-15, which is incorporated herein by reference, describe a reactive system in which primitive events can have attributes. The attributes may be associated with the event itself, such as a transaction ID, or they may be determined by some external condition at the time the event occurs. In specifying a rule based on such an event, a predicate (or condition) can be defined on these attributes such that, when the predicate is false, the occurrence of the event is “masked” and does not trigger an action specified by the rule.
Processing of the events when they occur is performed using a finite state machine, wherein evaluation of the conditions is done in a separate phase, after event processing has been completed.
ECA rules have received substantial research attention in the field of active database management systems. In these systems, ECA rules are attached to a database in order to monitor situations of interest that may occur in the database (or beyond the database, as appropriate), and trigger timely responses when the situations occur, even without an explicit request from a user or application. A technical report by Zimmer et al., entitled “A General Model for Specification of the Semantics of Complex Events in Active Database Management Systems,” C-LAB Report March 1997 (Cooperative Computing & Communication Laboratory, Paderborn, Germany), which is incorporated herein by reference, provides a survey and critique of work in this field, including various languages that have been developed for the specification of events and ECA rules.
One such language is “Snoop,” which is described by Chakravarthy et al., in a report entitled “Snoop: An Expressive Event Specification Language for Active Databases” (Tech. Report UF-CIS-TR-93-007, Department of Computer and Information Sciences, University of Florida, Gainesville, March, 1993), which is incorporated herein by reference. Snoop, like other event specification languages, defines certain event operators used for constructing complex events. The operators provided by Snoop include conjunction, disjunction and sequence, as well as “aperiodic” and “periodic” event operators. Aperiodic operators are used to express the occurrence of a particular event within an interval bounded by two or more other events. Periodic operators express the occurrence of a particular event within a specified time interval of the occurrence of a preceding event. In either case, an action may be triggered on every occurrence of the particular event, or only on the first occurrence.
SUMMARY OF THE INVENTION
It is an object of some aspects of the present invention to provide improved tools and systems for situation management.
It is a further object of some aspects of the present invention to provide tools and methods for classifying and responding to temporal relationships among events.
It is still a further object of some aspects of the present invention to provide efficient methods for processing events and conditions that occur.
In preferred embodiments of the present invention, a situation management system provides tools for defining intervals during which a given situation is meaningful and for detecting and reacting to the occurrence of the situation during such intervals. In the context of the present patent application and in the claims, an interval of this sort is referred to as a “lifespan.” A lifespan begins with an initiating event, or initiator, and ends with a terminating event, or terminator. The situation management system enables manipulation of the initiator and terminator, such as by attachment of conditions to the initiating and terminating events. It also allows multiple, interrelated lifespans to run concurrently, with predefined relations between the lifespans. Thus, the situation management system enables temporal relations among events to be defined and detected simply and flexibly.
In some preferred embodiments of the present invention, composition filtering and content filtering are jointly applied to detected situations. Composition filtering refers to detection of complex events, as described hereinabove, while content filtering refers to evaluation of the conditions applied to detected events. The situation management system allows a timing relationship to be defined between composition and content filtering, unlike systems known in the art, in which event detection and condition evaluation are distinct and independent processing stages. Thus, in the present system, composition and content filtering may be performed concurrently or, alternatively, content filtering may deferred and applied to events only at the end of a lifespan in which they occur. Concurrent composition and content filtering enables the system to discard immediately events that do not meet the specified conditions, thereby reducing the computation and storage burden on the system relative to systems known in the art.
In further preferred embodiments of the present invention, quantifiers are provided so as to define how the situation management system is to respond to repeated occurrences of a given event. Preferably, the quantifiers indicate to the system whether it is to react to the first or last instance of the event in a given lifespan, or to each instance in the lifespan. The quantifiers may be applied to substantially any type of event or situation detected by the system, including both simple and complex events, as well as events that serve as lifespan initiators and terminators.
There is therefore provided, in accordance with a preferred embodiment of the present invention, a method for situation management, including:
specifying a composite
Adi Asaf
Etzion Opher
Follansbee John
Holmes Michael B.
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