the university of north carolina at chapel hill evaluating the effectiveness of automatic pvr...

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Evaluating the Effectiveness of Automatic PVR ManagementKetan Mayer-PatelWesley Miaw

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Personal Video Recorders• Time-shifted viewing• Show archiving• Hundreds of hours worth of storage• “TV Guide” integration• Recommendations

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

PVR Recommendation

• Pros:♦ Total awareness♦ Learned viewing preferences

• Cons:♦ Inaccurate

PVR: Total awareness + Errorvs.

Human: Limited awareness + No error

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Simulation

• 180 days• PVR capacity: 100 half-hour

shows• Each half hour, save show of

highest utility.• Delete programs of lowest utility

as necessary.• End of day, compute total utility

and delete consumed shows.• First week ignored.

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

PVR Model

• Number of Channels• Viewer Consumption Rate• Content Utility Distribution

[0,1]• Utility Decay Rate• Selection Policy (Automatic or

Manual)

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

The Tradeoff

• 200 channels• 8 half-hour shows

viewed each day

• CUD gaussian z=10• 0.975 decay factor

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Channels

• X channels• 8 half-hour shows

viewed each day

• CUD gaussian z=10• 0.975 decay factor

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Consumption Rate

• 200 channels• X half-hour shows

viewed each day

• CUD gaussian z=10• 0.975 decay factor

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Content Utility Distribution

• 200 channels• 8 half-hour shows

viewed each day

• CUD gaussian z=X• 0.975 decay factor

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Decay Rate

• 200 channels• 8 half-hour shows

viewed each day

• CUD gaussian z=10• X decay factor

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Conclusion

• Margin of error has very little effect on automatic policy performance.

• Even if the automatic policy has very small error, a human with sufficiently high awareness will beat it.

• The automatic policy is useful to very unaware or very picky people.

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Looking Ahead

• Available content is overwhelming♦ Hundreds of channels♦ Thousands of program hours each day

• Broadcast is necessary♦ Video requires ~1GB/hour

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Recommendation Silliness• “I recorded an episode of Oprah…it

started recording all kinds of BET and hip-hop shows.” – Rapunzel

• “I taped a few Spanish-language soccer games…a year later stuff in Spanish is constantly being suggested to me.” – Matt

http://www.pvrblog.com/pvr/2003/07/pvrs_and_the_ga.html

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL

Resources

• http://www.wesman.net/~wesley/presentations/pvr.ppt

• http://www.wesman.net/~wesley/papers/pvr.pdf

• wesley@wesman.net