Welcome! Log In Create A New Profile


Assignment 4

Posted by PretoriaSux 
Announcements Last Post
Announcement SoC Curricula 09/30/2017 01:08PM
Announcement Demarcation or scoping of examinations and assessment 02/13/2017 07:59AM
Announcement School of Computing Short Learning Programmes 11/24/2014 08:37AM
Announcement Unisa contact information 07/28/2011 01:28PM
avatar Assignment 4
September 15, 2010 08:54AM

Anyone busy with Assignment 4? It seems substantially easier than assignment 3. I suspect most of the exam will be from assignment 3 as it is the most difficult one of the lot.

I've just finished question 1 and will be tackling question 2 during this week.
Re: Assignment 4
September 28, 2010 01:13PM
Most of Assignment 4 seems very easy. Only question 3, the planner seems to have a hugely long runtime. So far more than 8 CPU hours on a fast processor and counting. I'm going to go back and check for mistakes.
avatar Re: Assignment 4
September 28, 2010 03:30PM
Hi pvanheus,

I'm impressed you managed to write the state space out. I couldn't do this. I just guessed what the planner would do given how the text book described the planner. I'm stuck with question 3 at this point:

%   a
%  cb
% ====
% 1234

After I reach this state I'm not sure what the protected goal will be:
It must be one of the following:
Protected Goal: [clear(a)]
Protected Goal: [on(a,b)]
Protected Goal: [clear(a),on(a,b)]

Any ideas?
Re: Assignment 4
September 28, 2010 09:44PM
According to the textbook, the "protected goals" are the ones that have already been achieved *by actions in the plan*. So, looking at figure 17.4, there are a set of Goals, actions are chosen such that the action produces (at least one) Goal (Goal being a member of the set Goals). Actions, however, consume facts as well as producing them - so the thing about "protected goals" is that they are goals (i.e. facts) produced by an action.

So to answer your question - which of the facts in your example have been produced by an action (when that action has, itself, been chosen because it satisfies a goal)? Initially, no goals (facts) are on the "protected" list - however, as a goal is generated (and an action chosen), that goal enters the "protected" list until that list eventually is identical to the Goals list.

Does that make sense?
Sorry, only registered users may post in this forum.

Click here to login