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Previous research in wireless ad hoc networks typically assumes the use of omnidirectional antennas at all nodes. With omnidirectional antennas, while two nodes are communicating using a given channel, MAC protocols such as IEEE 802.11 require all other nodes in the vicinity to stay silent. With directional antennas, two pairs of nodes located in each(More)
This paper proposes a vehicle-to-vehicle communication protocol for cooperative collision warning. Emerging wireless technologies for vehicle-to-vehicle (V2V) and vehicle-to-roadside (V2R) communications such as DSRC are promising to dramatically reduce the number of fatal roadway accidents by providing early warnings. One major technical challenge(More)
Ad hoc networks formed without the aid of any established infrastructure are typically multi-hop networks. Location dependent contention and "hidden terminal" problem make priority scheduling in multi-hop networks significantly different from that in wireless LANs. Most of the prior work related to priority scheduling addresses issues in wireless LANs. In(More)
The aggregate throughput of a wireless ad hoc network depends on the channel capacity, channel utilization (i.e., the fraction of channel capacity used for generating good put), and the concurrent transmissions allowed in the network. While channel utilization is determined by MAC overhead, physical carrier sense has been used as an effective way to avoid(More)
We present the results, experiences and lessons learned from comparing a diverse set of technical approaches to indoor localization during the 2014 Microsoft Indoor Localization Competition. 22 different solutions to indoor localization from different teams around the world were put to test in the same unfamiliar space over the course of 2 days, allowing us(More)
We investigate the possibility of using directional antennas for medium access control in wireless ad hoc networks. Previous research in ad hoc networks typically assumes the use of omnidirectional antennas at all nodes. With omnidirectional antennas, while two nodes are communicating using a given channel, MAC protocols such as IEEE 802.11 require all(More)
In this paper, we study the emerging heterogeneous multi-radio network, focusing on interference issues due to simultaneous operation of multiple radios. A comprehensive review is given on the sources of coexistence interference, including transmitter noise, receiver blocking, and inter-modulation. We compare various coexistence techniques, and relevant(More)
Traditional medium access control (MAC) protocols utilize temporal mechanisms such as access probability or backoff interval adaptation for contention resolution. Temporal contention resolution aims to separate transmissions from different nodes in time to achieve successful transmissions. We explore an alternative approach for wireless networks - named(More)
Riboflavin (vitamin B(2)) participates in a variety of redox processes that affect plant defense responses. Previously we have shown that riboflavin induces pathogen resistance in the absence of hypersensitive cell death (HCD) in plants. Herein, we report that riboflavin induces priming of defense responses in Arabidopsis thaliana toward infection by(More)