Flockfs, a moderated group authoring system for wireless workgroups

Chandra, Surendar; Regola, Nathan

doi:10.4108/icst.mobiquitous2009.6814

Cited by 3 publications

(4 citation statements)

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“…Further work is required to capture availability traces from deployed applications. We are collecting such traces for our collaborative system [11,12] designed for wireless users.…”

Section: Session Durationmentioning

confidence: 99%

“…However, systems that required frequent update propagations did not benefit from history based prediction as much as systems that propagated updates less frequently. Our approach is practical; we used the policies developed to propagate updates in our moderated collaboration system called flockfs [11,12]. We incorporate the lessons learnt into our Yenta middleware.…”

Section: Introductionmentioning

confidence: 99%

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A Trace-Driven Analysis of Wireless Group Communication Mechanisms

Chandra¹,

Yu²

2012

ICST Trans Mobile Comm Appl

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Wireless access is increasingly ubiquitous while mobile devices that use them are resource rich. These trends allow wireless users to collaborate with each other. We investigate various group communication paradigms that underly collaboration applications. We synthesize durations when members collaborate using wireless device availability traces. Wireless users operate from a variety of locations. Hence, we analyzed the behavior of wireless users in universities, corporations, conference venues, and city-wide hotspots. We show that the availability durations are longer in corporations followed by university and then in hotspots. The number of simultaneously available wireless users is small in all the scenarios. The session lengths are becoming smaller while the durations between sessions are becoming larger. We observed user churn in all the scenarios. We show that synchronous mechanisms require less effort to maintain update synchronicity among the group members. However, distributed mechanisms require a large number of replicas in order to propagate updates among the users. For asynchronous mechanisms, we show that pull-based mechanisms naturally randomize the times when updates are propagated and thus achieve better performance than push based mechanisms. We develop an adaptive approach that customizes the update frequency using the last session duration and show that this mechanism exhibits good performance when the required update frequency intervals are large. We also show that for a given number of gossips, it is preferable to propagate updates to all available nodes rather than increasing the frequency while correspondingly reducing the number of nodes to propagate updates. We develop a middleware to illustrate the practicality of our approach.

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“…Further work is required to capture availability traces from deployed applications. We are collecting such traces for our collaborative system [11,12] designed for wireless users.…”

Section: Session Durationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Trace-Driven Analysis of Wireless Group Communication Mechanisms

Chandra¹,

Yu²

2012

ICST Trans Mobile Comm Appl

Self Cite

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“…To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. collaboration systems; results from this paper drives the propagation policies for the flockfs [4] collaboration system.…”

Section: Introductionmentioning

confidence: 99%

Designing an asynchronous group communication middleware for wireless users

Chandra²

2009

Proceedings of the 12th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems

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We evaluate an asynchronous gossiping middleware for wireless users that propagates messages from any group member to all the other group members. This propagation can either be implemented through distributed mechanisms or can be mediated through servers. Our analysis of asynchronous mechanisms using wireless user availability traces from an university, corporation and a hot spot federation shows that the fundamental impediment to the system performance is the wireless user availability patterns. We then investigate the relative performance for several distributed as well as server mediated approaches. We show that pull mechanisms effectively randomizes the times when messages are propagated and thus achieves better performance than push based mechanisms. We then develop an adaptive approach that customizes the propagation frequency using the last session duration and show that this mechanism exhibits good performance when the required propagation intervals are large. We also show that for a given number of gossips, it is preferable to propagate messages to all available nodes rather than increasing the frequency while correspondingly reducing the number of nodes to propagate messages. Our results allow middleware developers to choose the appropriate propagation model to satisfy their application constraints.

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“…The users also exhibited significant node churn. Further analysis of prior group collaboration systems [2] using wireless user availability traces from a variety of locales showed the practical limitations of prior collaboration systems. Systems such as Coda [3] and Ficus [4] had assumed fewer conflicting updates and better user availability than was observed among wireless users.…”

mentioning

confidence: 99%