Browsing by Author "Blum, Jeremy"

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    Effectiveness and Acceptance of Adaptive Intelligent Speed Adaptation Systems
    Arhin, Stephen; Eskandarian, Azim; Blum, Jeremy; Delaigue, Pierre; Soudbakhsh, Damoon (The National Academies of Sciences, Engineering, and Medicine, 2008)
    Intelligent speed adaptation (ISA) systems face significant consumer acceptance hurdles that limit the likelihood of widespread adoption, particularly in the United States. However, if these systems are designed as speed management systems rather than speed limiting systems, with adaptability to individual driving behavior, they may be more likely to meet with consumer acceptance. The results of a fixed-based driving simulator experiment that tested the acceptance and effectiveness of a new type of ISA, called an Advanced Vehicular Speed Adaptation System (AVSAS), are reported. The results of the experiment showed that AVSAS resulted in reductions in driver speeds across a range of roadway types. AVSAS is a speed management system that adapts to an individual driver’s speed behavior and the current driving situation. AVSAS resulted in an average reduction of 5% of the maximum speeds and 3% of the average speeds of the drivers on four road segments. As expected, AVSAS did not reduce driver speeds as much as the mandatory control ISA system, and the experiment confirmed the results of tests conducted on ISA systems largely in Europe. Conversely, the results revealed that more participants were willing to purchase AVSAS compared with the information or mandatory ISAs. Although these results show the promise of a trade-off between system effectiveness and acceptability that has been missing in mandatory and information ISA research, AVSAS suggests that a range of ISA system design requirements could encourage the adoption of ISA systems in the United States.
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    Synchronization challenges in media access coordination for vehicular ad hoc networks
    Blum, Jeremy; Natarajan, Rajesh; Eskandarian, Azim (Wiley, 2010-01-18)
    Vehicular ad hoc networks (VANETs) can support a wide range of future cooperative safety and efficiency applications. However, the node density and high demand for wireless media in these networks can lead to the Timeslot Boundary Synchronization Problem, in which increased transmission collisions occur due to back-off timer synchronization. This paper proposes an enhancement to the wireless access in vehicular environments (WAVE) communications architecture to address this problem, called RAndom Propagation Initiation Delay for the Distributed Coordination Function (RAPID DCF). The effectiveness of RAPID DCF is evaluated through simulations of both single-hop and multi-hop emergency messages. In these simulations, RAPID DCF was able to improve message delivery rates by as much as 35% and reduce multi-hop message latency by as much as 18%.