Yazhi Liu

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A VANET consists of vehicles equipped with on board units (OBUs) that can communicate with each other and the road side base stations. Due to the mobility and sparse distribution of vehicles, the delivery delay of messages in the VANET is mainly caused by the message transmissions between vehicles. The message delivery delay directly impacts the deployment(More)
With the increasing popularity of smart phones, a new collaborative sensing application, named participatory sensing, gradually appeared. The key idea of participatory sensing is to employ so many users to collect and share sensed data using their mobile phones. Current relevant applications are mainly focused on how to collect sensed data. Few methods have(More)
Vehicular Ad hoc Networks (VANETs) have been recently introduced to provide high-speed Internet access to vehicles by deploying 802.11 enhanced Roadside Units (RSUs) along roads. However, few file downloading oriented RSU deployment strategies have been proposed. In this paper, we propose a new RSU deployment strategy for file downloading in VANETs. The(More)
Widely distributed mobile vehicles wherein various sensing devices and wireless communication interfaces are installed bring vehicular participatory sensing into practice. However, the heterogeneity of vehicles in terms of sensing capability and mobility, and the participants' expectations on the incentives blackmake the collection of comprehensive sensing(More)
The wide distribution of mobile vehicles installed with various sensing devices and wireless communication interfaces has made vehicular mobile crowd sensing possible in practice. However, owing to the heterogeneity of vehicles in terms of sensing interfaces and mobilities, collecting comprehensive tempo-spatial sensing data with only one sensing vehicle is(More)
The ability of road vehicles to efficiently execute different sensing tasks varies because of the heterogeneity in their sensing ability and trajectories. Therefore, the data collection sensing task, which requires tempo-spatial sensing data, becomes a serious problem in vehicular sensing systems, particularly those with limited sensing capabilities. A(More)
Incentive strategy is important in participatory sensing, especially when the budget is limited, to decide how much and where the samples should be collected. Current auction-based incentive strategies purchase sensing data with lowest price requirements to maximize the amount of samples. However, such methods may lead to inaccurate sensing result after(More)
Opportunistic Network is a special kind of mobile Ad Hoc network in which communication nodes are sparsely distributed in the network area and the communicating opportunities between the nodes are created by the moving and encounter of the nodes. Achieving reliable data transmission in Opportunistic Networks is a great challenging task because there is no(More)