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 that integration.

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 info-emea@objectstore.net. www.objectstore.com

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