Peer-to-Peer Information Systems Week 14: Assignment #6 Old Dominion University Department of Computer Science CS 495/595 Fall 2003 Michael L. Nelson <mln@cs.odu.edu> 11/25/03

Assignment #6 Implement a trust metric as discussed in the previous lecture Summary: continue to leave “friends” out of the register verb add 2 verbs: listFriends listBadFriends

Friends List <friends> <friend> <host>cirrus.cs.odu.edu</host> <port>3923</port> <user>mln@cs.odu.edu</user> <client>VTRULZ</client> <trust average=“0.95” total=“25.65” frequency=“27” /> <friendsTrust average=“0.90” total=“315” frequency=“350” contributors=“11” /> </friend> </friends>

BadFriends List <badFriends> … <friend> <host>riaa.cs.odu.edu</host> <port>4000</port> <user>badguy@cs.odu.edu</user> <client>VTRULZ</client> <trust average=“0.125” total=“0.5” frequency=“4” /> <friendsTrust average=“0.066” total=“1” frequency=“15” contributors=“6”/> </friend> </badFriends>

Notes <friendsTrust> is an aggregate metric -- must be updated <trust> must be updated too user interaction: after each transaction can use default values can use any value between 0 - 1 specify preferences for trading partners: trust level age (i.e., number of transactions) grace period for new comers trust and age

Notes someway to show a list of friends and bad friends to the user someway to show trust level must be able to specify weights for local and remote trust must have a button to allow for on-demand polling of all friends issue listFriends and listBadFriends to all known friends (good) friends that is, you don’t communicate with bad friends

Grading 1/6 of your total project grade You will be graded on: 10 % of your course grade You will be graded on: in class presentation appearance of the interface nice & creative display of the metadata is encouraged!!! whether or not it works practice before you show up for class! robustness of handling exceptional conditions these are end-user applications… they should behave like them