Browsing by Author "Tan, Yong"

Now showing 1 - 4 of 4

Analysis of scale effects in preer-to-peer networks
(2008-06-01)
Li, Yung-Ming
;
Tan, Yong
;
Zhou, Yong-Pin
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
In this paper, we study both positive and negative scale effects on the operations of peer-to-peer (P2P) file sharing networks and propose the optimal sizing (number of peers) and grouping (number of directory intermediary) decisions. Using analytical models and simulation, we evaluate various performance metrics to investigate the characteristics of a P2P network. Our results show that increasing network scale has a positive effect on the expected content availability and transmission cost, but a negative effect on the expected provision and search costs. We propose an explicit expression for the overall utility of a content sharing P2P community that incorporates tradeoffs among all of the performance measures. This utility function is maximized numerically to obtain the optimal network size (or scale). We also investigate the impact of various P2P network parameters on the performance measures as well as optimal scaling decisions. Furthermore, we extend the model to examine the grouping decision in networks with symmetric interconnection structures and compare the performance between random- and location-based grouping policies.
Contracting Models for P2P Content Distribution
(2018-11-01)
Ghasemkhani, Hossein
;
Li, Yung-Ming
;
Moinzadeh, Kamran
;
Tan, Yong
;
管理學院
In recent years, peer-to-peer (P2P) networks have become an increasingly popular method for distributing digital content. In this study, we consider the development of optimal contracts for a P2P network by a profit-seeking provider to support the operations of an online file exchange service. By utilizing the principal-agent model of incentive theory, we propose appropriate reward and pricing schemes for profit-seeking P2P content distribution networks. We show that when peers are homogeneous, upload compensation increases with propagation delay uncertainty, maximum uploading nodes allowed, peers' provision cost and disutility of download delay, but decreases with the network size and content availability. We also characterize a general contracting model where there are a countable number of peer classes which are heterogeneous in their provisioning costs. For the case of two peer classes where optimal delays are separable, we derive the optimal upload compensations under different scenarios and show that the impact of operational parameters is quite similar to the case of homogeneous peers, lending support to the robustness of our analysis.
Quality of Service Based Pricing Schemes for Content Sharing in Peer-to-Peer Networks
(2017-08-01)
De, Prabuddha
;
Hao, Lin
;
Li, Yung-Ming
;
Tan, Yong
;
電子工程學系及電子研究所
In this paper, we study quality-of-service (QoS) based pricing schemes that serve as incentive mechanisms to induce sharing behaviors in Peer-to-Peer (P2P) networks. We incorporate operational QoS metrics into users' utility functions and demonstrate how they affect individual users' content sharing decisions. Using a game-theoretic model, our study reveals how organizations respond to the changes of operational QoS metrics in their design of pricing schemes for various business objectives at different stages of network evolution. Our results show that a higher upload capacity can foster rational sharing to start when the network is small; however, it also discourages sharing behaviors when the network becomes large. In order to induce a socially optimal behavior, a pricing scheme will not charge users for requesting content while compensating them for sharing content. Such compensation is found to increase faster with the network size when the network is large. In order to maximize the profit of a monopolistic provider, however, a pricing scheme will charge content requests with a positive price while providing less compensation to sharing users compared to the socially optimal scheme. When the network size is small, such compensation can be even negative, which implies that a monopolistic provider discourages content sharing when the network is small, but encourages it when the network becomes larger. In addition, we find that more information about peer upload capacity discourages peers to share.
Self-Organized Formation and Evolution of Peer-to-Peer Networks
(2013-06-01)
Li, Yung-Ming
;
Tan, Yong
;
De, Prabuddha
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Peer-to-peer (P2P) networks are social networks for pooling network and information resources and are considered superior conduits for distributed computing and data management. In this paper, we utilize the theories of social networks and economic incentives to investigate the formation of P2P networks with rational participating agents (active peers). The paper proposes a framework for multilevel formation dynamics, including an individual level (content-sharing decision and group selection) and a group level (membership admission, splitting, and interconnection). It is found that if the network size (the number of peer nodes) is sufficiently large, the stable (self-selected equilibrium) free-riding ratio could be nonzero, contrary to the common belief that everybody should free ride. The efficient (welfare-maximizing) free-riding ratio is not necessarily zero; that is, a certain degree of free riding is beneficial and should be tolerated. The sharing level in a network increases (decreases) with the download (upload) capacities of its peer nodes. In addition, the heterogeneity of content availability and upload capacity discourages sharing activities. Although the sharing level of a stable group is typically lower than that of an efficient group, the self-formed network may have a larger or smaller group size than what is efficient, depending on the structure of the group admission decision process. It is also observed that self-organized interconnections among groups lead to network inefficiency because the network may be over- or underlinked. To recover the efficiency loss during the formation process, we propose internal transfer mechanisms to force stable networks to become efficient.