Robert Jackson Marks

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— We consider the problem of maximizing the time-to-first-failure, defined as the time till the first node in the network runs out of battery energy, in energy constrained broadcast wireless networks. We discuss a greedy algorithm and prove that it solves the problem optimally for a broadcast application , in polynomial time, provided the complete power(More)
In this paper, we address the minimum power broadcast problem in wireless networks. Assuming nodes are equipped with omni-directional antennas, the inherently broadcast nature of wireless networks can be exploited to compute power efficient routing trees. We propose a 2-stage cluster-merge algorithm for computing minimum power broadcast trees. The cluster(More)
— We consider the problem of minimum power bidi-rectional topology optimization in wireless networks with sectored antennas. We first develop a mixed integer linear programming model for optimal solution of the problem with sectored antennas. Subsequently, we discuss a centralized heuristic algorithm which is based on Kruskal's algorithm for the minimum(More)
Wireless multicast/broadcast sessions, unlike wired networks , inherently reaches several nodes with a single transmission. For omnidirectional wireless broadcast to a node, all nodes closer will also be reached. Heuristics for constructing minimum power trees in wireless networks have been proposed by Wieselthier et al [1] and Stojmenovic et al [2]. In(More)
Intra-operative dosimetry in prostate brachytherapy requires 3D coordinates of the implanted, radioactive seeds. Since CT is not readily available during the implant operation, projection x-rays are commonly used for intra-operative seed localization. Three x-ray projections are usually used. The requirement of the current seed reconstruction algorithms is(More)
— Broadcasting in wireless networks, unlike wired networks, inherently reaches several nodes with a single transmission. For omni-directional wireless broadcast to a node, all nodes closer will also be reached. This property can be used to compute routing trees which minimize the sum of the transmitter powers. It has been shown that this problem is(More)
For omnidirectional wireless broadcast, if a node has sufficient power to broadcast to another node, it also has the ability to broadcast to all closer nodes. This is the wireless advantage. For the broadcast problem, one node (the source) is required to communicate to all other nodes, by a single transmission to the farthest node or using intermediate hop(More)
—Conservation of information (COI) popularized by the no free lunch theorem is a great leveler of search algorithms, showing that on average no search outperforms any other. Yet in practice some searches appear to outperform others. In consequence, some have questioned the significance of COI to the performance of search algorithms. An underlying foundation(More)
The multileaf collimator (MLC) hardware constraints are usually neglected in the process of intensity-modulated beam optimization. Consequently, it is not always possible to deliver planned beam modulation using dynamic MLC. Beam optimization is significantly diminished if the results must be approximated due to limitations imposed by the delivery device.(More)