108 research outputs found
Gap Acceptance Behavior at U - turn Median Openings – Case Study in Jordan
U-turns have been considered among the most hazardous locations on highways. The maneuvering of the driver at these locations is quite complex and risky. The behavior of the driver when turning is governed by the gap acceptance concept. In this study, the driver’s gap acceptance behavior at U-turn median openings was studied. 4 U-turn median openings in Irbid City were investigated. Data was collected by video recording. Two models were developed in this study. The first model estimated the time gap accepted by the driver. The second model calculated the turning function, which was used to estimate the probability of accepting gaps. Results showed that male drivers tended to accept shorter gaps than female drivers. Also, younger drivers were more likely to accept shorter gaps than older ones. The waiting time was also found to affect the gap acceptance behavior of the drivers. Drivers tended to accept shorter gaps after longer waiting times
Synchronization of multihop wireless sensor networks at the application layer
Time synchronization is a key issue in wireless
sensor networks; timestamping collected
data, tasks scheduling, and efficient communications
are just some applications. From all the
existing techniques to achieve synchronization,
those based on precisely time-stamping sync
messages are the most accurate. However, working
with standard protocols such as Bluetooth or
ZigBee usually prevents the user from accessing
lower layers and consequently reduces accuracy.
A receiver-to-receiver schema improves timestamping
performance because it eliminates the
largest non-deterministic error at the sender’s
side: the medium access time. Nevertheless, utilization
of existing methods in multihop networks
is not feasible since the amount of extra
traffic required is excessive. In this article, we
present a method that allows accurate synchronization
of large multihop networks, working at
the application layer while keeping the message
exchange to a minimum. Through an extensive
experimental study, we evaluate the protocol’s
performance and discuss the factors that influence
synchronization accuracy the most.Ministerio de Ciencia y Tecnología TIN2006-15617-C0
A Wildfire Prediction Based on Fuzzy Inference System for Wireless Sensor Networks
The study of forest fires has been traditionally considered as an important
application due to the inherent danger that this entails. This phenomenon
takes place in hostile regions of difficult access and large areas. Introduction of
new technologies such as Wireless Sensor Networks (WSNs) has allowed us to
monitor such areas. In this paper, an intelligent system for fire prediction based
on wireless sensor networks is presented. This system obtains the probability of
fire and fire behavior in a particular area. This information allows firefighters to
obtain escape paths and determine strategies to fight the fire. A firefighter can
access this information with a portable device on every node of the network. The
system has been evaluated by simulation analysis and its implementation is being
done in a real environment.Junta de Andalucía P07-TIC-02476Junta de Andalucía TIC-570
Multi-Hop Synchronization at the Application Layer of Wireless and Satellite Networks
Time synchronization is a key issue in wireless and
satellite networks; time-stamping collected data, tasks scheduling
or efficient communications are just some applications. From all
the existing techniques to achieve synchronization, those that
work at the MAC layer and can precisely timestamp sync
messages are the most accurate. However, working with standard
protocols, usually prevents the user from accessing lower layers
and consequently reduces accuracy. Receiver—receiver schema
improves time-stamping performance because it eliminates the
biggest non-deterministic error at the sender side; the medium
access time. Nevertheless, utilization of these methods in multihop
networks usually requires an extra amount of traffic. In this
paper we present a method which allows accurate
synchronization of large multi-hop networks such as satellite
networks working at the application layer while keeping the
message exchange to the minimum. Through an exhaustive
experimentation, we show the protocol’s performance and
analyze the factors that influence synchronization accuracy the
most.Ministerio de Ciencia y Tecnología TIN2006-15617-C03-0
Efficient and secure business model for content centric network using elliptic curve cryptography
https://onlinelibrary.wiley.com/doi/full/10.1002/dac.3839Initially, Internet has evolved as a resource sharing model where resources are identified by IP addresses. However, with rapid technological advancement, resources/hardware has become cheap and thus, the need of sharing hardware over Internet is reduced. Moreover, people are using Internet mainly for information exchange and hence, Internet has gradually shifted from resource sharing to information sharing model. To meet the recent growing demand of information exchange, Content Centric Network (CCN) is envisaged as a clean‐slate future network architecture which is specially destined for smooth content distribution over Internet. In CCN, content is easily made available using network caching mechanism which is misaligned with the existing business policy of content providers/publishers in IP‐based Internet. Hence, the transition from contemporary IP‐based Internet to CCN demands attention for redesigning the business policy of the content publishers/providers. In this paper, we have proposed efficient and secure communication protocols for flexible CCN business model to protect the existing business policies of the content publisher while maintaining the salient CCN features like in‐network content caching and Interest packet aggregation. To enhance the efficiency and security, the Elliptic Curve Cryptography (ECC) is used. The proposed ECC‐based scheme is analyzed to show that it is resilient to relevant existing cryptographic attacks. The performance analysis in terms of less computation and communication overheads and increased efficiency is given. Moreover, a formal security verification of the proposed scheme is done using widely used AVISPA simulator and BAN logic that shows our scheme is well secured
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