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Full-Text Articles in Physical Sciences and Mathematics

Vanet Applications Under Loss Scenarios & Evolving Wireless Technology, Adil Alsuhaim May 2023

Vanet Applications Under Loss Scenarios & Evolving Wireless Technology, Adil Alsuhaim

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In this work we study the impact of wireless network impairment on the performance of VANET applications such as Cooperative Adaptive Cruise Control (CACC), and other VANET applications that periodically broadcast messages. We also study the future of VANET application in light of the evolution of radio access technologies (RAT) that are used to exchange messages. Previous work in the literature proposed fallback strategies that utilizes on-board sensors to recover in case of wireless network impairment, those methods assume a fixed time headway value, and do not achieve string stability. In this work, we study the string stability of a …


Fast And Efficient Classification, Tracking, And Simulation In Wireless Sensor Networks, Hao Jiang Aug 2012

Fast And Efficient Classification, Tracking, And Simulation In Wireless Sensor Networks, Hao Jiang

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Wireless sensor networks are composed of large numbers of resource-lean sensors that collect low-level inputs from the physical world. The applications present challenges for programmers. On the one hand, lightweight algorithms are required given the limited capacity of the constituent devices. On the other, the algorithms must be scalable to accommodate large networks. In this thesis, we focus on the design and implementation of fast and lean (yet scalable) algorithms for classification, simulation, and target tracking in the context of wireless sensor networks. We briefly consider each of these challenges in turn.
The first challenge is to achieve high precision …


A Radio Link Quality Model And Simulation Framework For Improving The Design Of Embedded Wireless Systems, Sally Wahba May 2012

A Radio Link Quality Model And Simulation Framework For Improving The Design Of Embedded Wireless Systems, Sally Wahba

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Despite the increasing application of embedded wireless systems, developers face numerous challenges during the design phase of the application life cycle. One of the critical challenges is ensuring performance reliability with respect to radio link quality. Specifically, embedded links experience exaggerated link quality variation, which results in undesirable wireless performance characteristics. Unfortunately, the resulting post-deployment behaviors often necessitate network redeployment.
Another challenge is recovering from faults that commonly occur in embedded wireless systems, including node failure and state corruption. Self-stabilizing algorithms can provide recovery in the presence of such faults. These algorithms guarantee the eventual satisfaction of a given state …


Hybrid Bond-Order Potential For Silicon, Suleiman Oloriegbe Dec 2008

Hybrid Bond-Order Potential For Silicon, Suleiman Oloriegbe

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ABSTRACT
A new hybrid bond-order potential for silicon is developed. The functional form of the potential is derived from hybrid of expressions from empirical bond-order formalism and first principles approximations. The total energy is expressed as the sum of attractive, repulsive and promotion energies. By introducing a screening function derived from approximations to first principles expressions, the potential is made long-ranged by allowing covalent interactions beyond the first nearest neighbor shell of atoms in agreement with quantum mechanical descriptions of the bonding in silicon. Environment-dependent promotion energy is introduced that accurately accounts for energetic interactions due to changes in hybridization …


Adaptive Treatment Of Van Der Waals Interactions In Empirical Bond-Order Potentials With Application To Junction Formation In Carbon Nanotubes, Aibing Liu May 2007

Adaptive Treatment Of Van Der Waals Interactions In Empirical Bond-Order Potentials With Application To Junction Formation In Carbon Nanotubes, Aibing Liu

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Molecular dynamics (MD) simulation of reactive condensed-phase hydrocarbon systems is a challenging research area. The AIREBO potential is particularly useful in this area because it can simulate bond breaking and bond forming during chemical reactions. It also includes non-bonded interactions for systems with significant intermolecular interactions.

The first part of this dissertation describes a method to adaptively incorporate van der Waals interaction of carbon atoms into the AIREBO force field. In bond-order potentials, the covalent bonding interactions adapt to the local chemical environment, allowing bonded interactions to change in response to local chemical changes.
Non-bonded interactions should adjust to their …