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Data gathering is one of the most important services provided by wireless sensor networks (WSNs). Since the predominant traffic pattern in data gathering services is many-to-one communication, it is critical to understand the limitations of many-to-one information flows and devise efficient data aggregation protocols to support prolonged operations in WSNs.(More)
Previous studies of Escherichia coli phosphofructo-1-kinase have shown that mutation of Asp 127 lowers kcat by 5 orders of magnitude. As shown here, introduction of a second mutation (R252Q) that neutralizes a positive charge in the active site increases activity of D127S by 100 fold, suggesting that part of the effect of the Asp mutation may be attributed(More)
In wireless systems, accurate location estimation facilitates a variety of applications such as emergency localization, intelligent transport systems, inventory tracking, intruder detection , tracking of fire-fighters and miners, and home automation [1, 2]. In addition, location information can help optimize resource allocation and improve cooperation in(More)
Escherichia coli 6-phosphofructo-1-kinase was inhibited by high concentrations of ATP at alkaline pH. The mechanism of the inhibition was studied with two mutants generated by site-directed mutagenesis; I126A, with a Km for fructose-6-P that was more than two orders of magnitude higher than that of wild type but with minimal changes in kcat and Km for ATP,(More)
— The predominate traffic patterns in a wireless sensor network are many-to-one and one-to-many communication. Hence, the performance of wireless sensor networks is characterized by the rate at which data can be disseminated from or aggregated to a data sink. In this paper, we consider the data aggregation problem. We demonstrate that a data aggrega-tion(More)
The predominate traffic patterns in a wireless sensor network are many-to-one and one-to-many communication. Hence, the performance of wireless sensor networks is characterized by the rate at which data can be disseminated from or aggregated to a data sink. In this paper, the problem of data aggregation at a single sink is considered. It is shown that a(More)
— The predominate traffic patterns in a wireless sensor network are many-to-one and one-to-many communication. Hence, the performance of wireless sensor networks is characterized by the rate at which data can be disseminated from or aggregated to a data sink. In this paper, we consider the data aggregation problem. We demonstrate that a data aggregation(More)
The activity of Escherichia coli phosphofructo-1-kinase depends upon the dissociation of a group with a pK of approximately 6.6. Mutation of the 2 active site residues most likely to be titrated in this range, Asp-127 and Asp-129, lowered activity but produced little change in the pH dependence, suggesting that these residues while important to activity(More)
Mutations of either of two highly conserved residues near the active site of Escherichia coli phosphofructokinase, Ile-126 or Asn-128, produce no changes in the Km for ATP, relatively small changes in kcat, and a large increase in the Km for fructose 6-P, despite the fact that these residues are not directly involved in substrate binding. A computer(More)
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