I read the paper when it first came out. The arguments proposed in the paper are only applicable to rule engines that are object-oriented in design and not applicable to expert system shells like JESS, Clips or ART.
The limitations are the result of the design of the rule engine and not a limitation of the algorithm. Engines that use functional LISP/Prolog like design do not have these limittions. Claiming RETE is not good for CEP is a misunderstanding of RETE algorithm. Let's not confuse the limitations of a specific product(s) with the algorithm. There are many ways to solve the problem that do not require having 3600 facts. Trying to brute force a solution is neither elegant or efficient. On Mon, Mar 14, 2011 at 11:08 AM, Tromm, Martijn <martijn.tr...@ordina.nl> wrote: > In CEP you may need sliding time windows. If you want to check for > combinations of events or omissions of events in every time window that a > particular triggering event belongs to, let’s say we have a time-window of > one hour and need to update every second, then you have 3600 facts that > match just one event. With many events and many event-patterns that need to > be checked (subscriptions) you end up with a lot of nodes. This is > especially problematic in a real-time setting. > > Also you may need to consider (and thus store) a history of states of the > rete network. This is not natively supported. > > The following article > http://www.rn.inf.tu-dresden.de/uploads/pikm32-walzer.pdf describes the > problem pretty well and suggests an extension on the rete algorithm to deal > with a sliding time window operator. > > I am curious if there are other implementations or workarounds in Jess that > work well. > > Martijn > > > > But this is not a "Rete" issue. Rete is about managing facts for rules > containing patterns that result in boolean values. You can invent any number > of relational operators; they are just frontent syntactic sugar where > otherwise you have to use a call to a boolean function. > > -W > > On 14 March 2011 15:29, Tromm, Martijn <martijn.tr...@ordina.nl> wrote: > > Hi, > > Does anybody have any experience with complex event processing in Jess? > One of the shortcomings of Rete is that there is no native support for > temporal operators besides matching on timestamps and checking time > differences > > > > Disclaimer > Dit bericht met eventuele bijlagen is vertrouwelijk en uitsluitend bestemd > voor de geadresseerde. Indien u niet de bedoelde ontvanger bent, wordt u > verzocht de afzender te waarschuwen en dit bericht met eventuele bijlagen > direct te verwijderen en/of te vernietigen. Het is niet toegestaan dit > bericht en eventuele bijlagen te vermenigvuldigen, door te sturen, openbaar > te maken, op te slaan of op andere wijze te gebruiken. Ordina N.V. en/of > haar groepsmaatschappijen accepteren geen verantwoordelijkheid of > aansprakelijkheid voor schade die voortvloeit uit de inhoud en/of de > verzending van dit bericht. > > This e-mail and any attachments are confidential and are solely intended for > the addressee. If you are not the intended recipient, please notify the > sender and delete and/or destroy this message and any attachments > immediately. It is prohibited to copy, to distribute, to disclose or to use > this e-mail and any attachments in any other way. Ordina N.V. and/or its > group companies do not accept any responsibility nor liability for any > damage resulting from the content of and/or the transmission of this > message. -------------------------------------------------------------------- To unsubscribe, send the words 'unsubscribe jess-users y...@address.com' in the BODY of a message to majord...@sandia.gov, NOT to the list (use your own address!) List problems? Notify owner-jess-us...@sandia.gov. --------------------------------------------------------------------
