Handbook of Multimedia for Digital Entertainment and Arts- P5: The advances in computer entertainment, multi-player and online games, technology-enabled art, culture and performance have created a new form of entertainment and art, which attracts and absorbs their participants. The fantastic success of this new field has influenced the development of the new digital entertainment industry and related products and services, which has impacted every aspect of our lives. | 4 Personalization on a Peer-to-Peer Television System 107 a b Programs on-air 1 time 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 0 c Wach Time Percentage Wach Time Percentage Programs on-air 5 times Programs on-air 9 times Fig. 9 Program on-air times during to Jan 30 2003 Fig. 8 Percentage of watching time for programs with different on-air times number of watching users dropped. This is because some users left the channel when commercials began and zapped back again when they had supposedly ended. Figure 8 shows the number of users with respect to their percentages of watching times WatchLenght k m l OnAirlength m for programs with different number of times that they are broadcast on-air times of 1 5 and 9 . This shows clearly two peaks the larger peak on the left indicates a large number of users who only watched small parts of a program. The second smaller peak on the right indicates that a large number of users watched the whole programs once regardless of the number of times that the program was broadcast. That is the right peak happens in 20 of the programs that are broadcast five times one fifth and in 11 of the programs that are broadcast nine times 1 ninth etc. There is a third peak which happens in 22 in the programs which are broadcast nine times. This indicates that there are still a few users who watched the entire program twice for example to follow a series. These observations motivated us to normalize the percentage of watching time by the number of broadcastings of a program as explained in Eq. 2 in order to arrive at the measure of interest within a TV program. This normalized percentage is shown in Fig. 10. Now all the second peaks are located at the 100 position. 108 J. Wang et al. Fig. 10 Normalized percentage of watching time Watch Learning the User Interest Threshold The threshold level T above which the normalized percentage of watching time is considered to express interest in a TV program Eq. 3 is determined by evaluating the .
