Exploiting programmable architectures for WiFi/ZigBee inter-technology cooperation

The increasing complexity of wireless standards has shown that protocols cannot be designed once for all possible deployments, especially when unpredictable and mutating interference situations are present due to the coexistence of heterogeneous technologies. As such, flexibility and (re)programmability of wireless devices is crucial in the emerging scenarios of technology proliferation and unpredictable interference conditions. In this paper, we focus on the possibility to improve coexistence performance of WiFi and ZigBee networks by exploiting novel programmable architectures of wireless devices able to support run-time modifications of medium access operations. Differently from software-defined radio (SDR) platforms, in which every function is programmed from scratch, our programmable architectures are based on a clear decoupling between elementary commands (hard-coded into the devices) and programmable protocol logic (injected into the devices) according to which the commands execution is scheduled. Our contribution is two-fold: first, we designed and implemented a cross-technology time division multiple access (TDMA) scheme devised to provide a global synchronization signal and allocate alternating channel intervals to WiFi and ZigBee programmable nodes; second, we used the OMF control framework to define an interference detection and adaptation strategy that in principle could work in independent and autonomous networks. Experimental results prove the benefits of the envisioned solution

The Effect of Members' Satisfaction with a Virtual Community on Member Participation

The authors develop a four-dimensional scale to measure members' satisfaction with virtual communities. The dimensions consist of members' satisfaction with member-member interactions, organizer-member interactions, organizer-community interactions, and the community's site. Using a sample of 3605 members of a virtual community the authors investigate the effect of each satisfaction dimension on member participation and the moderating effect of membership length on the links between the satisfaction dimensions and member particip ation. The results reveal that satisfaction with member-member interactions, organizer-member interactions and the community's site have positive effects on member participation. Satisfaction with organizer-community interactions has no effect on member participation. The findings also show that the linkages between the satisfaction dimensions and member participation are moderated by membership length

The Effect of Members' Satisfaction with a Virtual Community on Member Participation

International audienceThe authors develop a four-dimensional scale to measure members' satisfaction with virtual communities. The dimensions consist of members' satisfaction with member-member interactions, organizer-member interactions, organizer-community interactions, and the community's site. Using a sample of 3605 members of a virtual community the authors investigate the effect of each satisfaction dimension on member participation and the moderating effect of membership length on the links between the satisfaction dimensions and member particip ation. The results reveal that satisfaction with member-member interactions, organizer-member interactions and the community's site have positive effects on member participation. Satisfaction with organizer-community interactions has no effect on member participation. The findings also show that the linkages between the satisfaction dimensions and member participation are moderated by membership length

Satisfaction with virtual communities of interests : effect on members' visit frequency

The authors develop a four-dimensional scale to measure members' satisfaction with virtual communities of interest (VCIs). The dimensions consist of members' satisfaction with member-to-member interactions, organizer-to-member interactions and organizer-to-community interactions, all of which come together on the VCI's site. Using a sample of 3605 members of a VCI, the authors investigated the effect of each satisfaction dimension on members' visit frequency, and the moderating effect of membership duration on the links between the satisfaction dimensions and visit frequency. The results reveal that satisfaction with member-to-member interactions, organizer-to-member interactions and the community's site has positive effects on members' visit frequency. Members' satisfaction with organizer-to-community interactions has no effect on visit frequency. The findings also show that membership duration strengthens two, and weakens one of the linkages between the satisfaction dimensions and members' visit frequency

Satisfaction with virtual communities of interest:Effect on members' visit frequency

International audienceThe authors develop a four-dimensional scale to measure members' satisfaction with virtual communities of interest (VCIs). The dimensions consist of members' satisfaction with member-to-member interactions, organizer-to-member interactions and organizer-to-community interactions, all of which come together on the VCI's site. Using a sample of 3605 members of a VCI, the authors investigated the effect of each satisfaction dimension on members' visit frequency, and the moderating effect of membership duration on the links between the satisfaction dimensions and visit frequency. The results reveal that satisfaction with member-to-member interactions, organizer-to-member interactions and the community's site has positive effects on members' visit frequency. Members' satisfaction with organizer-to-community interactions has no effect on visit frequency. The findings also show that membership duration strengthens two, and weakens one of the linkages between the satisfaction dimensions and members' visit frequency