Crowdsourcing civility: A natural experiment examining the effects of distributed moderation in online forums

Participation in discussions about the public interest can be enhanced by technology, but can also create an environment in which participants are overwhelmed by the quantity, quality, and diversity of information and arguments. Political participation is at a greater disadvantage than non-political activities in that participants from different parties already start out with established differences, which requires them to reach some form of common ground before progress can be made. Those seeking authentic deliberation are discouraged to participate when confronted with uncivil and inflammatory rhetoric. These issues are often exacerbated in online discussions, where lack of identity cues and low barriers to entry can lead to heightened incivility between participants, often labeled as “flaming” and “trolling”. This paper explores the extent to which moderator systems, tools online discussion forums use to manage contributions, can reduce information overload and encourage civil conversations in virtual discussion spaces. Using the popular website Slashdot as an example of sound moderation in a public discourse setting, we found that users move toward consensus about which and how comments deserve to be moderated. Using these findings, we explore how transferable these systems are for participation in public matters specifically to the unique attributes of political discussion. Slashdot's political forum provides a comparison group that allowed us to find quantitative and qualitative differences in political posting, comments, and moderation. Our results show that large scale, civil participation is possible with a distributed moderation system that enables regularly lively debates to be conducted positively because the system provides tools for people to enforce norms of civility.     

RTP-based broadcast streaming of high definition H.264/AVC video: An error robustness evaluation

In this work, we present an evaluation of the performance and error robustness of RTP-based broadcast streaming of high-quality high-definition (HD) H.264/AVC video. Using a fully controlled IP test bed (Hillestad et al., 2005), we broadcast high-definition video over RTP/UDP, and use an IP network emulator to introduce a varying amount of randomly distributed packet loss. A high-performance network interface monitoring card is used to capture the video packets into a trace file. Purpose-built software parses the trace file, analyzes the RTP stream and assembles the correctly received NAL units into an H.264/AVC Annex B byte stream file, which is subsequently decoded by JVT JM 10.1 reference software. The proposed measurement setup is a novel, practical and intuitive approach to perform error resilience testing of real-world H.264/AVC broadcast applications. Through a series of experiments, we evaluate some of the error resilience features of the H.264/AVC standard, and see how they perform at packet loss rates from 0.01% to 5%. The results confirmed that an appropriate slice partitioning scheme is essential to have a graceful degradation in received quality in the case of packet loss. While flexible macroblock ordering reduces the compression efficiency about 1 dB for our test material, reconstructed video quality is improved for loss rates above 0.25%.