Peer Selection Mechanism Research Articles

Impartial Peer Selection: An Annotated Reading List

The study of peer selection mechanisms presents a unique opportunity to understand and improve the practice of a group selecting its best members, despite each member of that group wanting to be selected. A prime example of such a setting is academic peer review, for which peer selection offers a variety of improvement directions. We present an annotated reading list covering the foundations of peer selection as well as recent and emerging work within the field.

Peer Effects in the Scotch Whisky Industry: A Test of Three Selection Mechanisms

The question facing managers when confronted with irreversible investment decisions is what framework they should choose to assess risks? Research suggests that managers may forgo the cognitive effort of building predictive models in favour of doing what their industry peers do. There is extensive empirical support for this so-called “peer effect”. However, the peers in peer-effect studies are usually identified by the researchers before testing the effect. In this paper, we do not identify peers but focus on alternative criteria that firms in the same industry may use to select peers. We argue that the literature points to three possible peer selection mechanisms: Regional cluster identity, similar resource size, and product market rivalry. We test these mechanisms using data on capacity expansion decisions by 117 distilleries from the Scotch Whisky industry from 1950-2010. We find that regional cluster identity and resource size are used to identify peers, but not product market competition.

Peer selection in opinion dynamics on signed social networks with stubborn individuals

This paper examines the impact of local peer selection on global opinion dynamics evolving on signed social networks, where both cooperative and antagonistic ties coexist. Specifically, we focus on how opinions of stubborn individuals can be efficiently learned by a signed social network using peer selection mechanism. First, we examine the correlation between the selection of influence anchors of stubborn individuals and the opinion formation of the signed social network. Then, we proceed to examine an eigenvector-based peer selection strategy and show how the strategy can be beneficial in the spreading efficiency of stubborn individuals’ opinions. Finally, how the local observations of peers’ opinions can be employed for peer selection is investigated, enabling a global opinion spreading efficiency enhancement through only local decision-making amongst social individuals. The application of the proposed peer selection strategy to the Friedkin-Johnsen opinion dynamics model on signed networks is discussed. Numerical examples are provided to demonstrate the theoretical results.

Network selection and influence effects on children’s and adolescents’ internalizing behaviors and peer victimization: A systematic review

In interpersonal models of developmental psychopathology, friendships and affiliations with peers have been considered as both consequences and determinants of children’s and adolescents’ internalizing behaviors and peer victimization. Longitudinal stochastic actor-oriented models (SAOMs) allow developmental researchers to disentangle peer selection processes where children or adolescents choose friends who are similar to themselves in internalizing behaviors or peer victimization from peer influence processes where children or adolescents become more similar to their friends over time in internalizing behaviors or peer victimization. This paper highlights the methods and results from a systematic review that screened 1447 empirical articles and located 28 using SAOMs to understand the interplay between peer social networks and internalizing behaviors or peer victimization. The results provide some evidence for both peer selection and influence related to depression, social anxiety, and peer victimization. Additionally, the results provide insight into directions for additional substantive and methodological research. Based on the findings of this review, future research is recommended that considers specific tests of peer selection and influence mechanisms, developmental and gender differences, individual and contextual moderators, multiplex relationships, methodological quality, and direct replication of prior studies.

Peer Influence and Adolescent Substance Use: A Systematic Review of Dynamic Social Network Research

Peer influence is one of the most proximal risk factors for adolescent substance use, and decades of theoretical and empirical research point to the importance of disentangling two interrelated processes that often co-occur: (1) peer selection is the process whereby adolescents choose to interact with one another; and (2) peer socialization is the process whereby individual behavior is shaped over time. Recent advancements in social network analyses, including the application of stochastic actor based models to developmental studies, have helped to disentangle the contributions of peer selection and socialization to adolescent substance use. The current study is the first systematic review of this literature, aiming to identify the extent to which adolescent substance use is associated with peer selection and socialization and highlighting patterns in study design across studies. Forty studies that met inclusion criteria were identified and systematically coded for study design characteristics (e.g., number of time points; number of covariates) and significant peer selection and socialization effects by substance use outcome. This review found support for peer selection effects on adolescent alcohol and tobacco use. Additionally, most studies reported peer socialization effects for adolescent alcohol use. However, relatively few studies reported socialization effects for tobacco use. Few studies reported on the peer effects associated with adolescent drug use. Variations in study design, including variations in the bounds of the network and in the covariates included in modeling, helped to identify areas for future research. Future research that helps to further clarify the roles of specific peer selection and socialization mechanisms will help with the development and refinement of prevention and intervention programs focused on reducing adolescent substance use.

MeNTor: A wireless-mesh-network-aware data dissemination overlay based on BitTorrent

IEEE 802.11s introduces MAC-layer extensions to enable vendor-independent and inter-operable WLAN mesh networks. Featuring automatic device interconnection and routing, 802.11s networks provide a higher scalability, flexibility, and robustness compared to common centralized WLAN infrastructures. As logical Peer-to-Peer (P2P) networks exhibit many of the characteristics of physical WLAN mesh networks on the application layer, it is obvious to consider solutions where both technologies interact to leverage robust distributed wireless applications, such as collaborative data distribution and synchronization in future smart cities. Envisioned scenarios include the administration and update deployment to specific device groups or the distributed caching and delivery of on-demand multi-media content to selected end points within a city-area wireless mesh network. Nevertheless, common P2P protocols, such as BitTorrent (BT), do not consider the structure of the physical underlay as they were primarily designed to be used over wired communication networks, such as large parts of the Internet. Hence, the default BT peer selection mechanism does not adapt to the network topology and varying medium utilization in wireless multi-hop networks. We present MeNTor, a set of optimizations to enable underlay-aware BT peer selection in WLAN mesh networks. It relies on cross-layer integration of default 802.11s information, only requiring minor extension of the BT application layer without introducing any MAC-layer modifications or traffic overhead. Our solution was evaluated in a 25-node real-world mesh test bed, using 10 different seed/leecher placements and comparing 18 parameter combination variants of MeNTor. Results show that average download times can be reduced by 30–40%, depending on the seed/leecher placement and parameter combination variant. Finally, we recommend the variant that performed best across all scenarios as prospective default configuration.

Priority-based scheduling scheme for live video streaming in peer-to-peer network

The P2P networks play a crucial role in communication and data transfer. During recent years the importance of P2P network is increasing due to its scalability and an easy cost-efficient model. From the last few years, a P2P network has also been playing a significant role in real-time data transmission. The features offered by P2P network for video on demand/ live video streaming are getting popular day by day. The key factors which affect the performance of the P2P network are Scheduling and Overlay. Scheduling schemes like push-based, pull-based scheduling schemes that can be further classified into FCFS, rarity based and deadline based scheduling schemes are not sufficient to fulfill the demand of P2P network. So in this paper, we have defined two new scheduling schemes which overcome the shortcomings of the existing schemes. These are priority based scheduling schemes which calculate the priority by combining the different factors which directly affect the performance of a network. This approach is a combination of priority based chunk selection and bandwidth aware peer selection mechanism, which improves the delay between the peers. A comparative analysis of the new priority-based scheduling scheme is done with previous approaches. The simulation results are shown in this paper verify the approach and depict that performance of network and quality of video receiver is improved with the use of priority based scheduling scheme. Performance analysis of scheduling schemes is evaluated using parameters like startup delay, end-to-end delay, playback delay, and frame redundancy, and for the quality of video the distortion, frame loss ratio of video parameter is used.

A Framework for Highly Reconfigurable P2P Trackers

The increasing use of Peer to Peer (P2P) applications,usually ruled by selfish behaviors, is posing new challengesto the research community. As contributions of this work we firstly devise a general framework underpinning the development of highly reconfigurable P2P trackers. Following that, a novel tracker architecture is proposed and several illustrative and enhanced tracker configurations are described. As result, the devised solution turns possible that flexible, programmable and adaptive peer selection mechanisms can be introduced at the P2P application level.The proposed solution assumes the general framework of one of the most popular P2P solutions, in this case a BitTorrent-like approach. As illustrative examples of the proposed framework capabilities, several straightforward and easy to deploy tracker configuration examples are presented, including methods for qualitative differentiation of swarm peers and advanced P2P Traffic Engineering mechanisms fostering the collaboration efforts between ISPs and P2P applications. Both the framework and the devised tracker configurations are validated resorting tosimulation experiments.

Peer startup process and initial offset placement in peer-to-peer (P2P) live streaming systems

We measure and study the peer startup process in P2P live streaming systems and focus on a critical issue in this aspect: How a peer initializes its buffer status when it joins a channel, i.e., initial offset placement of the peer’s buffer in the startup stage. We build a general model of peer startup process in chunk-based P2P streaming systems and present two initial offset placement schemes we inferred from the measurement results of real systems: Fixed padding (FP) scheme and proportional placement (PP) scheme. With FP scheme, the initial buffer offset is simply set to the offset reported by the reference neighbor peer of the new peer plus a fixed padding. With PP scheme, the initial buffer offset is set to the offset of the reference neighbor peer plus an advance proportional to the reference neighbor peer’s offset lag or buffer width. We evaluate the performance of these two schemes, and find that the FP scheme, although simple, is not practical to be adopted in real P2P live streaming systems, and PP scheme is stable when the placement is based on offset lag, but will be unstable when it is based on buffer width if the chunk fetching strategy and neighbor peer selection mechanism are not properly designed. We then report our detailed measurement results of PPLive and UUSee, two popular commercial P2P streaming systems. The measurement results show that PPLive adopts the PP scheme based on buffer width and has good performance. UUSee, however, adopts FP scheme in its early version and has relatively low performance, and it later upgrades to use the PP scheme in its new version and consequently obtains better performance. These results show that initial offset placement is a critical design issue in P2P live streaming systems, and the PP scheme presented in this paper is a good algorithm for this purpose. Our analytical and measurement results could be useful for guiding the analysis and design of buffering protocols for P2P live streaming systems.

Online Learning in BitTorrent Systems

We propose a BitTorrent-like protocol based on an online learning (reinforcement learning) mechanism, which can replace the peer selection mechanisms in the regular BitTorrent protocol. We model the peers' interactions in the BitTorrent-like network as a repeated stochastic game, where the strategic behaviors of the peers are explicitly considered. A peer that applies the reinforcement learning (RL)-based mechanism uses the observations on the associated peers' statistical reciprocal behaviors to determine its best responses and estimate the corresponding impact on its expected utility. The policy determines the peer's resource reciprocations such that the peer can maximize its long-term performance. We have implemented the proposed mechanism and incorporated it into an existing BitTorrent client. Our experiments performed on a controlled Planetlab testbed confirm that the proposed protocol 1) promotes fairness and provides incentives to contributed resources, i.e., high capacity peers improve their download completion time by up to 33 percent, 2) improves the system stability and robustness, i.e., reduces the peer selection fluctuations by 57 percent, and (3) discourages free-riding, i.e., peers reduce their uploads to free-riders by 64 percent as compared to the regular BitTorrent protocol.

An Extension of Virtual Globe to Build On‐Demand Geospatial Data Sharing Capability Using Peer‐to‐Peer Technology

AbstractIn the virtual globe system, ever higher performance is demanded for high quality service, especially when requesting intensive data from large‐scale networks, such as large scene 3D city models with fine textures. Extending the virtual globe platform from the present centralized mode into a decentralized mode can significantly improve platform capacity and service quality without additional investment in hardware, but presents new challenges such as the time cost of finding a peer, unstable offering, and low service capacity. A GeoODP2P network is designed based on specific features of spatial data transmission. Next, we discuss peer selection mechanisms that relieve the negative influence of peers, and propose a pre‐fetch mechanism that takes advantage of the unique characteristics of the P2P environment. This article implements a simulation system for a GeoODP2P network and presents a prototype platform that incorporates P2P functionality. Peer selection and pre‐fetch mechanisms are studied and tested on this simulation system. The prototype platform run in a real scenario demonstrates the effectiveness of applying P2P to a virtual globe platform.

Testing multiple levels of influence in the intergenerational transmission of alcohol disorders from a developmental perspective: the example of alcohol use promoting peers and μ-opioid receptor M1 variation.

This study examined the interplay between the influence of peers who promote alcohol use and μ-opioid receptor M1 (OPRM1) genetic variation in the intergenerational transmission of alcohol use disorder (AUD) symptoms while separating the "traitlike" components of AUD symptoms from their age-specific manifestations at three ages from emerging adulthood (17-23 years) to adulthood (29-40 years). The results for males were consistent with genetically influenced peer selection mechanisms as mediators of parent alcoholism effects. Male children of alcoholics were less likely to be carriers of the G allele in single nucleotide polymorphism A118G (rs1799971), and those who were homozygous for the A allele were more likely to affiliate with alcohol use promoting peers who increased the risk for AUD symptoms at all ages. There was evidence for women of an interaction between OPRM1 variation and peer affiliations but only at the earliest age band. Peer influences had stronger effects among women who were G-carriers. These results illustrate the complex ways in which the interplay between influences at multiple levels of analysis can underlie the intergenerational transmission of alcohol disorders as well as the importance of considering age and gender differences in these pathways.

Understand traffic locality of peer-to-peer video file swarming

Peer-to-peer (P2P) file sharing systems, most notably BitTorrent (BT), have achieved tremendous success among Internet users. Although this communication paradigm does not need a dedicated server infrastructure, it is putting unprecedented traffic pressure to Internet Service Providers (ISPs) over inter-ISP links.P2P locality has therefore been examined to address this challenge. Such an approach explores the access to local resources to optimize the inter-ISP traffic. However, most of these approaches have focused on a global strategy, and attempted to change the peer selection mechanism, which potentially affect the random topology of BT and thus reduces its robustness. The content and the peer diversities are seldom discussed, particularly the video file swarms of distinct characteristics.In this paper, we for the first time examine the different BT contents and peer properties in regards to the locality issues through a large-scale measurement. We demonstrate the distinct characteristics of video file swarms, and find that the distribution of the AS clusters (a set of peers belonging to the same AS) follows the Mandelbrot–Zipf law. Our results also suggest that the peer in few ASes are more likely to form large AS clusters and most ASes on the Internet do not have enough potential for locality. Therefore, a global locality approach may not be our best choice. We then address the problem through a selective locality approach based on a novel peer prediction method.

ISP-friendly P2P live streaming

Peer-to-Peer (P2P) applications generate large amounts of Internet network traffic. The wide-reaching connectivity of P2P systems is creating resource inefficiencies for network providers. Recent studies have demonstrated that localizing cross-ISP (Internet service provider) traffic can mitigate this challenge. However, bandwidth sensitivity and display quality requirements complicate the ISP-friendly design for live streaming systems. To this date, although some prior techniques focusing on live streaming systems exist, the correlation between traffic localization and streaming quality guarantee has not been well explored. Additionally, the proposed solutions are often not easy to apply in practice. In our presented work, we demonstrate that the cross-ISP traffic of P2P live streaming systems can be significantly reduced with little impact on the streaming quality. First, we analytically investigate and quantify the tradeoff between traffic localization and streaming quality guarantee, determining the lower bound of the inter-AS (autonomous system) streaming rate below which streaming quality cannot be preserved. Based on the analysis, we further propose a practical ISP-friendly solution, termed IFPS , which requires only minor changes to the peer selection mechanism and can easily be integrated into both new and existing systems. Additionally, the significant opportunity for localizing traffic is underscored by our collected traces from PPLive, which also enabled us to derive realistic parameters to guide our simulations. The experimental results demonstrate that IFPS reduces cross-ISP traffic from 81% up to 98% while keeping streaming quality virtually unaffected.

Caching for BitTorrent-Like P2P Systems: A Simple Fluid Model and Its Implications

Peer-to-peer file-sharing systems are responsible for a significant share of the traffic between Internet service providers (ISPs) in the Internet. In order to decrease their peer-to-peer-related transit traffic costs, many ISPs have deployed caches for peer-to-peer traffic in recent years. We consider how the different types of peer-to-peer caches--caches already available on the market and caches expected to become available in the future--can possibly affect the amount of inter-ISP traffic. We develop a fluid model that captures the effects of the caches on the system dynamics of peer-to-peer networks and show that caches can have adverse effects on the system dynamics depending on the system parameters. We combine the fluid model with a simple model of inter-ISP traffic and show that the impact of caches cannot be accurately assessed without considering the effects of the caches on the system dynamics. We identify scenarios when caching actually leads to increased transit traffic. Motivated by our findings, we propose a proximity-aware peer-selection mechanism that avoids the increase of the transit traffic and improves the cache efficiency. We support the analytical results by extensive simulations and experiments with real BitTorrent clients.

On tradeoffs between cross-ISP P2P traffic and P2P streaming performance

Peer-to-peer (P2P) technology greatly scales up traditional Internet streaming service. However, the philosophy that peers help one another distribute video content produces a large amount of cross-ISP P2P traffic. Newly proposed ISP-friendly P2P mechanisms reduce the cross-ISP P2P traffic by using locality-based peer selection mechanisms, in which the peers tend to connect to other peers in the same ISP domain. However, one unanswered question is how can we achieve the tradeoffs between the cross-ISP P2P traffic and the P2P streaming performance if there are conflicts between them. In this paper, we propose a rate allocation mechanism for achieving the tradeoffs between the cross-ISP P2P traffic and the P2P streaming performance. We model the tradeoffs as a multiobjective optimization problem and solve it using the Goal Attainment method. The evaluation result shows that our mechanism is able to achieve the tradeoffs between the conflicts and maintain good fairness among the peers and the streaming overlays.

Understanding Skype signaling

Skype is without a doubt today's VoIP application of choice. Its amazing success has drawn the attention of both telecom operators and the research community. There is a great interest in characterizing Skype's traffic, understanding its internal mechanisms, and learning about its users' behavior. One of the most interesting characteristics of Skype is that it relies on a P2P infrastructure for the exchange of signaling information that is distributed between peers. Leveraging the use of an accurate Skype classification engine that we recently designed, we now report the results of our experimental study of Skype signaling based on extensive passive measurements collected from our campus LAN. We avoid the need to reverse-engineer the Skype protocol, and we instead adopt a black-box approach. We focus on signaling traffic in order to infer certain interesting properties regarding overlay maintenance and, possibly, the overlay structure as well. Our results show that, even though the signaling bandwidth used by normal peers is exiguous, it may nonetheless account for a significant portion of the total traffic generated by a single Skype client. Skype performs peer discovery and refresh by using a large number of single packet probes. This may be as effective for the purpose of overlay maintenance as it is costly, at least from the viewpoint of layer-4 network devices. At the same time, single-packet probes account for only a minor fraction of all signaling traffic: therefore, we wish to explore more deeply the traffic that is exchanged among the more stable peers, in an attempt to learn how the peer selection mechanism actually operates. Measurements were collected during April and August 2007. In particular, during the second month of sampling, the Skype network suffered a worldwide service outage. We compare the results collected during the two time periods, and we demonstrate the striking impacts on the signaling network as a result of the outage.

Semantic social overlay networks

Peer selection for query routing is a core task in peer-to-peer networks. Unstructured peer-to-peer systems (like Gnutella) ignore this problem, leading to an abundance of network traffic. Structured peer-to-peer systems (like Chord) enforce a particular, global way of distributing data among the peers in order to solve this problem, but then encounter problems of network volatility and conflicts with the autonomy of the peer data management. In this paper, we propose a new mechanism, INGA, which is based on the observation that query routing in social networks is made possible by locally available knowledge about the expertise of neighbors and a semantics-based peer selection function. We validate INGA by simulation experiments with different data sets. We compare INGA with competing peer selection mechanisms on resulting parameters like recall, message gain or number of messages produced.

Service differentiated peer selection: an incentive mechanism for peer-to-peer media streaming

We propose a service differentiated peer selection mechanism for peer-to-peer media streaming systems. The mechanism provides flexibility and choice in peer selection to the contributors of the system, resulting in high quality streaming sessions. Free-riders are given limited options in peer selection,if any, and hence receive low quality streaming. The proposed incentive mechanism follows the characteristics of rank-order tournaments theory that considers only the relative performance of the players, and the top prizes are awarded to the winners of the tournament. Using rank-order tournaments, we analyze the behavior of utility maximizing users. Through simulation and wide-area measurement studies, we verify that the proposed incentive mechanism can provide near optimal streaming quality to the cooperative users until the bottleneck shifts from the streaming sources to the network.

Peer and adolescent substance use among 6th-9th graders: latent growth analyses of influence versus selection mechanisms.

This study analyzed peer-influence versus peer-selection mechanisms in adolescent tobacco, alcohol, and marijuana use. Participants were surveyed 3 times, with 1-year intervals, about peers' substance use and their own use; Sample 1 had 1,190 participants (initial mean age = 12.4 years), Sample 2 had 1,277 participants (initial mean age = 11.5 years). Latent growth analyses that were based on composite scores indicated that initial peer use was positively related to rate of change in adolescent use, supporting the influence mechanism; there was little evidence for a selection mechanism. Difficult temperament, poor self-control, and deviance-prone attitudes were related to initial levels for both peer and adolescent use. It is concluded that peer influence is the primary mechanism during middle adolescence. Temperament-related attributes may be predisposing to early experimentation and deviant-peer affiliations.