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Full-Text Articles in Computer Engineering

Adaptive Multicast On Mobile Ad Hoc Networks Using Tree-Based Meshes With Variable Density Of Redundant Paths, Sangman Moh, Sang Jun Lee, Chansu Yu Nov 2009

Adaptive Multicast On Mobile Ad Hoc Networks Using Tree-Based Meshes With Variable Density Of Redundant Paths, Sangman Moh, Sang Jun Lee, Chansu Yu

Electrical and Computer Engineering Faculty Publications

Multicasting has been extensively studied for mobile ad hoc networks (MANETs) because it is fundamental to many ad hoc network applications requiring close collaboration of multiple nodes in a group. A general approach is to construct an overlay structure such as multicast tree or mesh and to deliver a multicast packet to multiple receivers over the overlay structure. However, it either incurs a lot of overhead (multicast mesh) or performs poorly in terms of delivery ratio (multicast tree). This paper proposes an adaptive multicast scheme, called tree-based mesh with k-hop redundant paths (TBM k ), …


Proactive Service Migration For Long-Running Byzantine Fault-Tolerant Systems, Wenbing Zhao, H. Zhang Apr 2009

Proactive Service Migration For Long-Running Byzantine Fault-Tolerant Systems, Wenbing Zhao, H. Zhang

Electrical and Computer Engineering Faculty Publications

A proactive recovery scheme based on service migration for long-running Byzantine fault-tolerant systems is described. Proactive recovery is an essential method for ensuring the long-term reliability of fault-tolerant systems that are under continuous threats from malicious adversaries. The primary benefit of our proactive recovery scheme is a reduced vulnerability window under normal operation. This is achieved in two ways. First, the time-consuming reboot step is removed from the critical path of proactive recovery. Second, the response time and the service migration latency are continuously profiled and an optimal service migration interval is dynamically determined during runtime based on the observed …


Minimizing Spatial And Time Reservation With Collision-Aware Dcf In Mobile Ad Hoc Networks, Lubo Song, Chansu Yu Jan 2009

Minimizing Spatial And Time Reservation With Collision-Aware Dcf In Mobile Ad Hoc Networks, Lubo Song, Chansu Yu

Electrical and Computer Engineering Faculty Publications

Carrier sensing is widely adopted in wireless communication to protect data transfers from collisions. For example, distributed coordination function (DCF) in IEEE 802.11 standard renders a node to defer its communication if it senses the medium busy. For the duration of deferment, each frame carries, in its MAC header, a 16-bit number in microseconds during which any overhearing node must defer. However, even if the carrier signal is detected, both ongoing and a new communication can be simultaneously successful depending on their relative positions in the network or equivalently, their mutual interference level. Supporting multiple concurrent communications is …