Homework 1

Due October 4

Extend the simple database agents example to do brokering: The Simple Interface Agent should find (via the matchmaker) at least two simple database wrappers, and choose the "cheapest" one to answer the query.

Agent 1: Simple Interface Agent {SIA]. The simple interface agent should allow a user to query a remote database for the cheapest price. You may choose a VERY limited type a query (i.e., price of a stock given the ticker symbol, name of a movie given an actor, capital of a state given the state, etc.). Do not worry about elaborate query languages. You may either prompt the user for the queries on the command line, or in a window widget if you want to be elaborate. Your SIA and the SDBWs should find each other via the Matchmaker; they should not use hardcoded names and locations.

Enter a ticker symbol: IBM
Sending a remote query....the price of IBM is 158.
Enter a ticker symbol: MTZ
Sending a remote query...That symbol is unknown to the remote database.

Agent 2: Simple Database Wrapper [SDBW]. The simple database wrapper should accept two types of queries: a query meaning "how much would it cost to answer this domain query", and a domain query itself. You can simply encode a small database in a Java hashtable, although you may wrap a file or a web site if that's just too boring for you. The "cost" of answering a query should be randomly generated (so different agents will be chosen at different runs of the system).

Question 1: Are these "intelligent agents" (Chapter 1)? Why or why not? If not, what could you do to make them intelligent? If they are intelligent, do they compose a multi-agent system? What multi-agent interactions (from Chapter 2) would be useful in this application context?

Question 2: One important concept in multi-agent software engineering is robustness.
A multiagent system should be very robust to all kinds of serious and transient failures. How robust is your solution? Make a comprehensive list of robustness traits and indicate if your solution has these traits. A robust behavior is one that (1) does not result in a fatal error and (2) either reports the error or attempts to transparently recover from the error. For example:

SDBW robust to malformed queries?
SIA and SDBW robust to Matchmaker failure (at startup; later on)?
SIA robust to absence of an SDBW (at startup? after query is sent?)
Assume all the students use one matchmaker, and several produce SDBWs for your domain. Robust (at both ends)?

Also, indicate which traits could be handled by more complex task structures, and which would require some completely new support.

Homework Goals: To develop a basic familiarity with DECAF. Learn how to start up and shutdown agents, including the ANS and Matchmaker. Basic familiarity with the PlanEditor, and with writing Java Agent Actions. A feeling for the different types of thinking needed at the implementation level vs. the "theory" level.