Piet Westendorp

Psychological backgrounds for inducing cooperation in peer-to-peer television

Television and the Internet have proven to be a popular combination for both broadcasters and viewers. Because of this popularity they are increasingly facing the consequences of central bottlenecks, which could be overcome by taking a different approach: Peer-to-Peer (P2P) technology. P2P systems can only be successful with as much cooperation among as many users as possible. We explain how this cooperation is hard to enforce, and how inducing it might be more successful. This paper lists relevant psychological backgrounds that can be used to induce this cooperation, along with possible applications for our system called Peer-to-Peer Television (P2P-TV).

Exploring the Acceptability of Delayed Reciprocity in Peer-to-Peer Networks

Using Peer-to-Peer (P2P) technology for distributing Television programs to many viewers simultaneously can only be successful if users cooperate voluntarily and massively. The current BitTorrent protocol only enforces instantaneous bandwidth exchange within the context of one video file. We explore ways to induce user cooperation flexible over time and over type of resources. Essential resources for a P2P system are: bandwidth, injections, moderations, and appreciations. Social exchange theory is taken as a background for addressing the inducement of cooperation in a P2P-TV system called Tribler. This theory helps to explain how the acceptability of delayed reciprocity can be influenced by the specificity of the exchangeable resources and by the relationship types between individuals. This paper presents the results from a study among 36 participants about the acceptability of delayed reciprocity in a P2P-TV system, under varying relationship types and specificity of exchangeable resources.

A questionnaire-based study on delayed reciprocity in a P2P-tv system

Using peer-to-peer (P2P) technology for distributing video files to many viewers simultaneously can only be successful if users cooperate voluntarily and massively. The current BitTorrent protocol enforces instantaneous bandwidth exchange within the context of one video file. To better exploit available resources for P2P-TV systems, such as our Tribler (www.tribler.org) software, we explore ways to induce user cooperation flexible over time and resources. The research is based on the social exchange theory and is done in two steps. First, the impact of social distance expressed in the degrees of separation (DoS) on the trust in reciprocity is investigated. Second, the DoS are combined with the kind of exchangeable resources typical for P2P-TV systems (i.e. injections and bandwidth) to find the influence of these variables on the accepted delay in reciprocity. The discussion will focus on the relation between trust in reciprocity and the accepted delay in reciprocity.

Learning Efficiency with Text, Pictures, and Animation in On-Line Help

To test the relative efficiency and learning effect of text, pictures, and animation in on-line help systems, six versions of an on-line help system for telephones were designed. The operational information was presented in either text, pictures, or animation and presented either with or without spatial information (in pictures). Subjects were asked to perform thirteen tasks, using these six versions of the instructions and to do the same tasks again, using the same version of the instructions, one week later. The results show that only presenting the operational information via text is the most efficient. Subjects using instructions in animation needed significantly more time than those using the text or picture versions. Adding spatial information (in pictures) was counterproductive: without this information subjects performed better in all versions. Performing the same tasks with identical instructions one week later produced the same results, but the differences were much smaller. Therefore, it has been concluded that text remains the most efficient medium as long as users have to apply the instructions immediately. If the time needed to read/see the instructions is deducted, animation turns out to be the most efficient medium. It is therefore concluded that animation could be the best medium for learning how to operate a device.