5,380 research outputs found
Distributed Time-Sensitive Task Selection in Mobile Crowdsensing
With the rich set of embedded sensors installed in smartphones and the large
number of mobile users, we witness the emergence of many innovative commercial
mobile crowdsensing applications that combine the power of mobile technology
with crowdsourcing to deliver time-sensitive and location-dependent information
to their customers. Motivated by these real-world applications, we consider the
task selection problem for heterogeneous users with different initial
locations, movement costs, movement speeds, and reputation levels. Computing
the social surplus maximization task allocation turns out to be an NP-hard
problem. Hence we focus on the distributed case, and propose an asynchronous
and distributed task selection (ADTS) algorithm to help the users plan their
task selections on their own. We prove the convergence of the algorithm, and
further characterize the computation time for users' updates in the algorithm.
Simulation results suggest that the ADTS scheme achieves the highest Jain's
fairness index and coverage comparing with several benchmark algorithms, while
yielding similar user payoff to a greedy centralized benchmark. Finally, we
illustrate how mobile users coordinate under the ADTS scheme based on some
practical movement time data derived from Google Maps
An Optimal Game Theoretical Framework for Mobility Aware Routing in Mobile Ad hoc Networks
Selfish behaviors are common in self-organized Mobile Ad hoc Networks
(MANETs) where nodes belong to different authorities. Since cooperation of
nodes is essential for routing protocols, various methods have been proposed to
stimulate cooperation among selfish nodes. In order to provide sufficient
incentives, most of these methods pay nodes a premium over their actual costs
of participation. However, they lead to considerably large overpayments.
Moreover, existing methods ignore mobility of nodes, for simplicity. However,
owing to the mobile nature of MANETs, this assumption seems unrealistic. In
this paper, we propose an optimal game theoretical framework to ensure the
proper cooperation in mobility aware routing for MANETs. The proposed method is
based on the multi-dimensional optimal auctions which allows us to consider
path durations, in addition to the route costs. Path duration is a metric that
best reflects changes in topology caused by mobility of nodes and, it is widely
used in mobility aware routing protocols. Furthermore, the proposed mechanism
is optimal in that it minimizes the total expected payments. We provide
theoretical analysis to support our claims. In addition, simulation results
show significant improvements in terms of payments compared to the most popular
existing methods
A Survey of Techniques for Improving Security of GPUs
Graphics processing unit (GPU), although a powerful performance-booster, also
has many security vulnerabilities. Due to these, the GPU can act as a
safe-haven for stealthy malware and the weakest `link' in the security `chain'.
In this paper, we present a survey of techniques for analyzing and improving
GPU security. We classify the works on key attributes to highlight their
similarities and differences. More than informing users and researchers about
GPU security techniques, this survey aims to increase their awareness about GPU
security vulnerabilities and potential countermeasures
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