Here are some ideas for instructive or simply difficult exercises. I have
indicated the approximate difficulty and/or effort with 0 through 4. Notice,
though, that 4 may be difficult for novices, and that >=3 requires "fluent
Java".
*** Movie Database (1)
Given XML data on flicks, actors and roles:
<database>
<movie title="Casablanca"/>
...
<actor name="Humphrey Bogart"/>
<actor name="Ingrid Bergman"/>
...
<role actor="Humphrey Bogart" movie="Casablanca"/>
<role actor="Ingrid Bergman" movie="Casablanca"/>
...
</database>
load this into WM. Write rules such as
- all movies of some actor/actrice;
- all actors/actrices of a movie
. all movies where two given actors/actrices are in the cast
*** Shortest path (3)
Given XML data on cities and travel costs
<graph start="Indianapolis" goal="Columbus">
<nodes id="Atlanta"/>
<nodes id="Boston"/>
<nodes id="Columbus"/>
...
<edges nodeA="Atlanta" nodeB="Boston" cost="5"/>
...
<edges nodeA="Boston" nodeB="Columbus" cost="6"/>
...
</graph>
load this into WM. Study Dijkstra's Algorithm for finding the shortest path
and implement it using rules.
*** Polygons and Points (3)
Given XML data describing a polygon and some isolated points P1, P2,...
inside or outside of the polygon:
<database>
<polygon name="M">
<edge>
<p1 name="p1" x="0" y="0"/>
<p2 name="p2" x="10" y="0"/>
</edge>
...
<edge>
<p1 name="p5" x="0" y="10"/>
<p2 name="p1" x="0" y="0"/>
</edge>
</polygon>
<point name="P1" x="4" y="4" />
<point name="P2" x="20" y="5" />
...
</database>
load this data into WM. Write a rule determining, for each point, whether it
is inside or
outside. (The basic algorithm can be found in textbooks on geometry.)
*** Lexical Analysis
Implement a Lexical Analyzer.
(a) Write individual rules for all combinations of <state,token-class>,
doing the action on the RHS (2)
(b) Design a generic rule interpreting facts defining
<state,token-class,action>. (4)
*** Range Checking
(a) Write a rule checking whether some (numeric) slot s of fact F is in
[a,b], reporting out-of-bounds. (0)
(b) Design a system that will accept any number of facts of type R defining
<F,s,a,b>.
Write a rule matching an R-fact with F=F' if there are facts from F' present
in the WM
and create (programmatically) the corresponding range-checking rule. Add the
rules to the Engine and
run. (4)
*** Populating a Grid (2)
Given m x n (m,n >= 1) facts Cell<x,y,b> (x, y integer) representing an
m-by-n grid, write rules setting slot b
in the border cells, i.e. where x=1 or y=1 or x=m or y=n. Make sure you
achieve the minimum amount of
rule activations!
*** Battleships (2)
Given a quadrant of sea, represented by a 10x10 grid, where battleships may
be located in 1,2, 3 or
4 horizontal or vertical neighbouring cells, write rules ascertaining that
the situation is "safe":
no battleship may occupy a cell that this one of the 8 immediate neighbours
of a cell occupied
by another battleship. Report violations.
-W
On Sun, Aug 23, 2009 at 4:34 PM, Wolfgang Laun <[email protected]>wrote:
> The Jess wiki contains some interesting examples, I should mention, since
> you didn't.
>
> Also, you might look at other (public domain) RBS and theit examples.
> Sometimes you'd have to rewrite (Drools doesn't use CLIPS as a language),
> sometimes you might be able to take it with perhaps just minor adaptions
> (CLIPS).
>
> -W
>
>
> On Sun, Aug 23, 2009 at 12:17 PM, jarno niemelä <[email protected]> wrote:
>
> > Hello.
> >
> > I am planning a rule based programming course and we are using JESS
> > for programming assignments.
> > And being typical lazy teacher I would appreciate any material that
> > anyone is willing to share to get me started :)
> >
> > We are using "JESS in action" as a course book but I could use good
> > references on programming assignments and
> > other couse related materials.
> >
> > So if anyone has material they are willing to share or can suggest
> > good programming examples or excercises on top of
> > what comes with JESS and good, I would greatly appreciate that.
> >
> > The focus of the course is to give students enough experience so that
> > they could start using JESS and other rule engines
> > in their future work assignments and when they go out working for
> > companies.
> >
> > I am using rule based systems in my own work and have noticed that
> > they save a huge amount of work in complex real life
> > systems so I would like to train future generations of engineers that
> > they don't have to hard code business logic with Java or Python
> > and spend most of their time on constant re-factoring.
> >
> > Also I would appreciate any pointers on other good books to read on
> > rule based programming and using them in business environment.
> >
> > Jarno
> >
> >
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