RFID and Complex Event Processing
Increasingly, RFID implementations are facing the need to translate raw
RFID event data into meaningful information that may be processed by enterprise
applications. Although the software action groups of the EPCglobal are
defining standard interfaces for enterprise applications, there has been
little discussion of exactly how such an EPCIS layer might be constructed,
and extended, and what tools and techniques will help developers answer
the questions that will be posed by real time applications. Complex Event
Processing (CEP) is a new technology that is precisely designed for this
kind of problem. CEP was developed to solve problems in other applications
that involve large numbers of real time events. For example, all areas
of financial services from fraud detection in credit cards and online
banking to tracking global electronic transactions between banks, stock
trading and SEC regulatory conformance, electronic supply chain negotiations,
autonomous control processes, and of course military command and control.
CEP is just now beginning to be applied to RFID.
What is CEP? CEP deals with the task of processing multiple streams of
simple events with the goal of identifying the meaningful events within
those streams. Examples of simple events include church bells ringing,
the appearance of a man in a tuxedo, a girl in a flowing white gown, and
rice flying through the air. A complex event is what one infers from the
simple events: a wedding is happening. CEP helps discover complex, inferred
events by analyzing other events: the bells, the man and girl in wedding
gear, and the rice flying through the air.
So the job of CEP is to consume simple event-oriented data, apply sets
of event processing rules to those events in real time, and, through that
processing, to separate the wheat from the chaff. This is exactly the
challenge at hand for RFID event applications: the data collected from
passive tags is, like the wedding example, simple. The business decisions
to be made on that data are not simple.
At the heart of CEP is an event query language, or EQL. The EQL uses events,
time, causality and event abstraction as its fundamental elements, rather
than data and a relational algebra, as SQL does. In The Power of Events,
an Introduction to Complex Event Processing in Distributed Enterprise
Systems, David Luckham of Stanford University defines CEP and proposes
an EQL. There are some commercial implementations of other CEP languages,
and there are emerging standards that are related to CEP, from the EPCIS
to WS-Eventing and WS-Notification. All these standards need CEP.
According to Gartner’s Roy Schulte, CEP will become a common computing
model within five to ten years. But developers aren’t sitting still
- you can build CEP systems today in languages like Java or C++, although
EQL techniques help simplify the job of writing event driven applications.
Another benefit of CEP is the use of dynamic architectures that are uniquely
designed to process multiple event streams in parallel, and in real time.
Typically, these architectures are networks of communicating event processing
agents called event processing networks (EPNs) that can capture multiple
streams of events, aggregate events, and query them, all at the same time.
As event volume and velocity grow, these EPN architectures will be critical
to scale RFID systems.
So keep an eye out for CEP as it grows in stature in the software industry.
As more and more applications move from a simple “slap and ship”
RFID deployment mentality, they will continue to rise in importance. As
adopters of RFID begin to see the need to integrate RFID tracking with
inventory control processes and other business processes in real time,
to improve those processes, CEP will be the technology needed to achieve
Mark Palmer has 15 years of experience in the operational
data management and middleware and is vice president of marketing and
RFID technical evangelist with ObjectStore, a division of Progress Software.
David Luckham is Professor Emeritus at Stanford University, USA.
ObjectStore® is a global provider of real-time data management products.
Its products enable corporate data caching and complex event processing,
and its leading object database is renowned for performance and scalability.
In the UK ObjectStore can be reached on 01753 216350 or at email@example.com.