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— The static spectrum allocation scheme used by the legacy wireless communication systems results in spectrum under-utilization. To make the best of the precious spectrum resource, any chunk of idle spectrum should be allowed to be used as a communication channel, subject to certain physical constraints, and this is the essence of the open spectrum(More)
This article introduces a sensor information networking architecture, called SINA, that facilitates querying, monitoring, and tasking of sensor networks. SINA plays the role of a middleware that abstracts a network of sensor nodes as a collection of massively distributed objects. The SINA's execution environment provides a set of configuration and(More)
A graph matching approach is proposed in this paper for solving the task assignment problem encountered in distributed computing systems. A cost function defined in terms of a single unit, time, is proposed for evaluating the effectiveness of task assignment. This cost function represents the maximum time for a task to complete module execution and(More)
— In a match-making system, sources (producers) advertise generated data without any particular destination in mind. Destinations (consumers) are determined based on their interests (via subscriptions) in receiving the produced data. Advertisements and subscriptions are matched by the underlying network service. We propose to facilitate match-making(More)
Existing work on placing additional relay nodes in wireless sensor networks to improve network connectivity typically assumes homogeneous wireless sensor nodes with an identical transmission radius. In contrast, this paper addresses the problem of deploying relay nodes to provide fault tolerance with higher network connectivity in heterogeneous wireless(More)
— In mobile wireless ad hoc networking environments , such as the Future Combat System (FCS), the shared wireless communication medium is an inherently limited resource and is collision prone. In this paper, we propose to adapt the Dual Busy Tone Multiple Access (DBTMA) protocol for use with directional antennas, which further increases effective channel(More)
The advent of technology has facilitated the development of networked systems of extremely small, low power devices that combine programmable general purpose computing with multiple sensing and wireless communication capability. This networked system of pro-grammable sensor nodes, together form a sensor network , poses unique challenges on how information(More)
—The topology of an ad hoc network has a significant impact on its performance in that a dense topology may induce high interference and low capacity, while a sparse topology is vulnerable to link failure and network partitioning. Topology control aims to maintain a topology that optimizes network performance while minimizing energy consumption. Existing(More)
— Traditional MAC protocols used in ad hoc networks employ omnidirectional antennas. Recently, directional antennas have emerged as an alternative due to their capability of spatial reuse, low probability of detection, robustness to jamming, and other beneficial features. In this paper, we conducted a comparison study of existing directional and(More)