No offense or bragging intended, but Jess is within a factor of 2 of
CLIPS performance in virtually every case (with a good JVM, of
course.) JNI is quite slow, so the CLIPS/Java combination is likely to
be substantially slower than Jess. Be sure to benchmark, and try not
to be influsneced by superstitions.
I think Satish boggavarapu wrote:
[Charset iso-8859-1 unsupported, filtering to ASCII...]
> Hi Fred,
>
> I am going to use Java irrespective of the inference engine. A collegue of
> mine wrote a JNI wrapper around CLIPS some time back through which he can
> register Java Objects and pass the commands as eval strings. Java methods
> can also be called on the LHS of the pattern just like Jess. Works well with
> (Name, Obj, Val) triplet representation. (Not the most convinient way, but
> serves the purpose). The idea behind his implementation is to use CLIPS till
> JESS achieves CLIPS efficiency levels(eagerly waiting for it to happen) and
> then migrate to JESS with out to many changes. Cant blame him, his manager
> wanted to see a big telecom application using JESS before going for it.
>
> Luckily i have my options open.
> -Satish.
>
> PS: Are there any good papers on model based problem solving paradigms other
> than MIT's Prof. Davis paper.
>
>
>
> -----Original Message-----
> From: Fred Freitas [mailto:[EMAIL PROTECTED]]
> Sent: Friday, April 06, 2001 1:28 PM
> To: Satish boggavarapu; ejfried
> Cc: jess-users
> Subject: RE: JESS: Representation Paradigm
>
>
> HI Satish
>
> No doubt you must use Jess! Not only is it well supported and many of the
> improvement decisions are voted (!) but also the popularity of Java and its
> better OO implementation are relevant pros: packages for multi-agent
> communication, networking, ontologies and many others are freely available
> and the number is growing each day.
>
> CLIPS advantages are efficiency and direct compatibility to Ontolingua,
> where you can reuse directly a lot of ontologies.
>
> Fred Freitas
> ----------------------------------------------------------
> PhD. student - Artificial Intelligence & Internet
> Universidade Federal de Santa Catarina - Brasil
> Currently at University of Karlsruhe - Germany
>
> -----Original Message-----
> From: Satish boggavarapu [mailto:[EMAIL PROTECTED]]
> Sent: Friday, April 06, 2001 7:17 PM
> To: 'Fred Freitas'; ejfried
> Cc: jess-users
> Subject: RE: JESS: Representation Paradigm
>
>
> Hi,
>
> I am working on a Network Fault Diagnosis System. Since it is going to be a
> real time system performance is an important issue even though i cant ignore
> expressiveness. As usal its a tradeoff mix and match and i have to find the
> right mix. The network topology consists of a large number of (say
> 20000-30000) network elements with considerable number of attributes say
> 5-10.
>
> Now coming to the representation issue. I have couple of choices as i
> mentioned in my previous mail. Either represent it as (Name, obj, val)
> triplets or as Objects (may not be java beans). I can use either CLIPS/COOL
> or JESS. Before deciding on any one technology i want to have an idea of the
> advantages and disadvantages on all sides.
>
> Fred thanks for your views on the use of an object systems. The network
> domain knowledge is more of a domain description than representing its
> functionalities. And i am looking at an object based frame work on which i
> can write rules for pattern matching. Some of the future work i am planning
> to do involves hooking up a knowledge base editor and explanation
> capability.
>
> Ernest, the explanation you provided regarding slot modification in an
> object system, is that a JESS specific statement? Or can that be applied in
> general? Say for COOL aswell.
>
> If i have java code (Normal java classes as opposed to beans) to represent
> the taxonomy of Network, what are the problems i might face in creating
> COOL/JESS objects out of them. Is it a good idea to store them in the
> inference engine memory and keep the references in a manager object outside
> and manipulate both from the inference engine and the java world?
>
> Ernest, are there any plans of introducing sliding window timers and
> counters to JESS which can be used on the LHS? Say i want to fire the rule
> when certain patterns match certain number of times in a given time window.
>
> I would appreciate if anyone can provide their insight in to these aspects.
>
> Ernest and fred thanks again for your views.
>
> -Satish.
>
>
>
> -----Original Message-----
> From: Fred Freitas [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, April 05, 2001 2:48 PM
> To: ejfried; Satish boggavarapu
> Cc: jess-users
> Subject: RE: JESS: Representation Paradigm
>
>
> Hi Satish,
>
> For me,one important issue here is expressiveness. COOL (and now Jess
> integrated with ontology editor Protege using JessTab package) provides
> frame-based representation capabilities, what also brings some advantages:
>
> . Multiple inheritance
> . slots can be instances of other classes
> . easy declarative knowledge reuse (there are lots of "off-the-shelf"
> ontologies)
> . concepts can be translated to other knowledge representation formalisms
> . slots are usually more legible and trackable than methods (due to
> information hiding)
>
> * When i modify an attribute slot in Object representation, does it retract
> > all the attribute slots in that object and assert them again? Or just that
> > particular slot? (Sounds dumb?) :)
>
> This is a quite important question. I heard in a conference that any change
> in an object will fire the evaluation of ALL of its methods calls in any
> rule LHS. If this holds true, this is one advantage for declarative
> representations, which will only evaluate the LHSs referring to the
> particular slot.
>
> In my view, this choice must focus on what's important to your system -
> expressiveness or efficiency -, what must be represented - a domain
> description or its functionalities - and what is to be reused - frame-based
> ontologies or objects and beans.
>
> Fred Freitas
> ----------------------------------------------------------
> PhD. student - Artificial Intelligence & Internet
> Universidade Federal de Santa Catarina - Brasil
> Currently at University of Karlsruhe - Germany
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On
> Behalf Of [EMAIL PROTECTED]
> Sent: Thursday, April 05, 2001 7:33 PM
> To: Satish boggavarapu
> Cc: [EMAIL PROTECTED]
> Subject: Re: JESS: Representation Paradigm
>
>
> JavaBeans will have a little more performance overhead than plain
> facts, but not too terribly much. There is no per-match storage
> overhead. There is really no performance-related reason to avoid using
> Beans.
>
> If you modify a JavaBean property, a PropertyChangeEvent should be
> sent to Jess. Jess then responds to this event precisely as if a
> (modify) command were being executed on an ordinary fact: it retracts
> the "shadow fact" that represents that Bean, modifies the slot, then
> reasserts the shadow fact. If you call (modify) on a shadow fact
> directly, what happens is that Jess set the corresponding Bean
> property, anticipating that the PropertyChangeEvent will be received
> and lead to the shadow fact being modified as above. As a result, the
> performance overhead of using Beans amounts to basically one or two
> method calls and a few variable accesses -- a negligible contribution
> considering that this one modification may cause thousands of partial
> matches to be created or destroyed.
>
> Using pre-existing Beans is nice because it makes life easy if you're
> connecting Jess up to some larger system. I imagine you could also
> create fact types as Beans just for convenience sake, as you intimate
> below, but honestly the thought had never occurred to me before.
>
>
> I think Satish boggavarapu wrote:
> [Charset iso-8859-1 unsupported, filtering to ASCII...]
> >
> > Hi All,
> >
> > What are the advantages and disadvantages of representing a network
> taxonomy
> > using objects (COOL, JESS objects) VS as (SlotName, Object, Value)
> triplets
> > in CLIPS and JESS.
> >
> > Are there any performance hits using object representation instead of
> > triplet representation? Inheritence issues? Partial matches?
> >
> > When i modify an attribute slot in Object representation, does it retract
> > all the attribute slots in that object and assert them again? Or just that
> > particular slot? (Sounds dumb?) :)
> >
> > I think one known disadvantage of using triplets is readability
> >
> > For Ex: 10000 elements, each with 10 attributes.
> >
> > Any views?
> >
> > Thanks in Advance
> > Satish.
> >
> > ---------------------------------------------------------------------
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> [EMAIL PROTECTED]
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> >
>
>
>
> ---------------------------------------------------------
> Ernest Friedman-Hill
> Distributed Systems Research Phone: (925) 294-2154
> Sandia National Labs FAX: (925) 294-2234
> Org. 8920, MS 9012 [EMAIL PROTECTED]
> PO Box 969 http://herzberg.ca.sandia.gov
> Livermore, CA 94550
>
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>
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>
---------------------------------------------------------
Ernest Friedman-Hill
Distributed Systems Research Phone: (925) 294-2154
Sandia National Labs FAX: (925) 294-2234
Org. 8920, MS 9012 [EMAIL PROTECTED]
PO Box 969 http://herzberg.ca.sandia.gov
Livermore, CA 94550
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