Panayotis Antoniadis

Comparing economic incentives in peer-to-peer networks

Users who join a peer-to-peer network have, in general, suboptimal incentives to contribute to the network, because of the externalities that exist between them. The result is an inefficient network where the overall levels of contribution are less than would be the case if each peer acted in the interests of the entire network of peers. Incentives provided in the form of prices or contribution rules that require no money transfers can play an important role in reducing these inefficiency effects. The problem in designing such incentive schemes is information: Designing an optimal incentive scheme requires complete knowledge of the types and preferences of the individual peers and their identities. In this paper we discuss the above issues in terms of a simple but representative example by introducing the basic economic concepts and models. We then investigate the practical issue of designing several simpler incentive schemes requiring less information and compare their efficiency loss to the optimal. We show using numerical analysis that these schemes converge to a fixed proportion of the full information optimal as the number of peers in the network becomes large. This result means that it is not necessary to collect large amounts of information, or to undertake complicated calculations, in order to implement the correct incentives in a large peer-to-peer network.

A survey on predicting the popularity of web content

Social media platforms have democratized the process of web content creation allowing mere consumers to become creators and distributors of content. But this has also contributed to an explosive growth of information and has intensified the online competition for users attention, since only a small number of items become popular while the rest remain unknown. Understanding what makes one item more popular than another, observing its popularity dynamics, and being able to predict its popularity has thus attracted a lot of interest in the past few years. Predicting the popularity of web content is useful in many areas such as network dimensioning (e.g., caching and replication), online marketing (e.g., recommendation systems and media advertising), or real-world outcome prediction (e.g., economical trends). In this survey, we review the current findings on web content popularity prediction. We describe the different popularity prediction models, present the features that have shown good predictive capabilities, and reveal factors known to influence web content popularity.

From popularity prediction to ranking online news

News articles are an engaging type of online content that captures the attention of a significant amount of Internet users. They are particularly enjoyed by mobile users and massively spread through online social platforms. As a result, there is an increased interest in discovering the articles that will become popular among users. This objective falls under the broad scope of content popularity prediction and has direct implications in the development of new services for online advertisement and content distribution. In this paper, we address the problem of predicting the popularity of news articles based on user comments. We formulate the prediction task as a ranking problem, where the goal is not to infer the precise attention that a content will receive but to accurately rank articles based on their predicted popularity. Using data obtained from two important news sites in France and Netherlands, we analyze the ranking effectiveness of two prediction models. Our results indicate that popularity prediction methods are adequate solutions for this ranking task and could be considered as a valuable alternative for automatic online news ranking.

Market models for P2P content distribution

The new p2p networking paradigms offer new possibilities for content distribution over the Internet. We propose a model that treats peers as independent economic agents buying and selling content and investigate the basic economic properties of such a market managed p2p content distribution network. Initially, we assume that no peer has the content, and there is a substantial initial cost to bring it within the peer group. The bargaining position and hence the price that can be posted by an agent having the content depends on the cost to transport the content to the requesting peer, its value, and the number of other agents providing the same content. We discuss the influence of parameters such as the maximum number of the competitive offers allowed by the system, content popularity, its value to the agents, and the transport costs, taking into account the risk of the first agent incurring the initial content cost.

Federation of virtualized infrastructures: sharing the value of diversity

By federating virtualized computing and network resources one can significantly increase their value thanks to gains from statistical multiplexing and increases in resource diversity (more distinct locations, technologies, etc.). Successful federation depends upon resource providers being able to agree on policies: how to share the profit generated by external customers and/or how to allocate the resources contributed by the federation participants to their affiliated users. This papers main contribution is a method that enables organizers of a federation to evaluate the relative importance of the resources contributed by each participant. We build on coalitional game theory concepts and formulate a generic economic model of federation that captures the notion of diversity, which is relevant for a variety of overlay services, and notably the networking research experiments that are running today on PlanetLab. Based on this model, we propose the Shapley value as a means for participants to share the value of federation. We show how this approach can help in the design of policies that encourage infrastructure owners to federate.

Incentives for resource sharing in self-organized communities: From economics to social psychology

In this position paper we analyze the benefits of enabling virtual communities to self-organize and introduce a novel research direction for providing incentives, required in this context, for resource sharing and cooperation. We argue that the social aspect, which is missing from today’s peer-to-peer (p2p) systems, should be seen both as a goal and a means for self-organized virtual communities to be built and fostered. Hence, we propose that the ongoing research efforts for designing effective incentive mechanisms in p2p systems, based on principles from game theory, should be directed towards a more sociological/psychological approach. We also provide some possible first steps towards this direction.

Self-organised virtual communities: bridging the gap between web-based communities and P2P systems

In this paper, we argue for the benefits of enabling the self-organisation of virtual online communities, which today are mainly formed and operated by centrally managed web servers. However, self-organisation requires community members themselves to contribute different types of resources (e.g., bandwidth, storage, etc.), as in the case of Peer-to-Peer (P2P) systems. Unfortunately, this cooperation cannot be taken for granted. To address this obstacle, we introduce the notion of a cross-layer incentive mechanism. The main idea is to encourage the contribution of low-level resources using social incentives generated at a higher (social) layer. We believe that this type of incentive mechanism will play a central role toward the realisation of self-organised virtual communities and enable users to take advantage of the attractiveness and value of web-based communities, on the one hand, and the externalities and flexibility of P2P networks, on the other hand. We make a first step toward this direction: a) we categorise the different types of social incentives applicable in this context and b) we provide insights for the design of the appropriate social software required to map the behaviour of the participants at the resource-sharing layer with suitable rewards at the social layer.

Enforcing efficient resource provisioning in peer-to-peer file sharing systems

In this paper we focus on content availability as the main good provided by a p2p file sharing system and consider peer availability, the amount of time peers stay connected sharing their files, as their main contribution. We wish to study the effectiveness of incentive mechanisms which enforce contribution by somehow relating it with consumption. Towards this end, we propose a mechanism who wishes to regulate the time required for peers to stay on-line sharing their files by dictating a fixed upload throughput used by uploading peers and thus a certain average time for a download to finish. We formulate and analyze a suitable economic model focusing on peer availability in order to understand the role of this important system parameter and provide the means to efficiently tune it.

Peer-to-peer wireless LAN consortia: economic modeling and architecture

We address the incentive issues that arise in a peer-to-peer WLAN consortium (P. Antoniadis et al., 2003). We explore the use of flexible rules on reciprocity to guide domain policies and develop a suitable economic model that demonstrates the basic characteristics of our system.

Flânerie between Net and Place Promises and Possibilities for Participation in Planning

The information and communication technology (or ICT) revolution adds new possibilities for providing information about places and communities that may be used in planning processes. In this article we introduce the practice of flânerie in the physical and virtual space as a method to produce representative images of contemporary social life. We suggest how planning may be instrumental in shaping a public good alternative in this emerging hybrid social space, where the practice of flânerie can stimulate engagement in deliberative planning practices. Finally, we discuss some of the trade-offs and design choices for eliciting information from citizens about their localities to understand how future development may lead to qualitative changes in community life.