MAC Layer Misbehavior Effectiveness and Collective Aggressive Reaction Approach

Abstract-Current wireless MAC protocols are designed to provide an equal share of throughput to all nodes in the network. However, the presence of misbehaving nodes (selfish nodes which deviate from standard protocol behavior in order to get higher bandwidth) poses severe threats to the fairness aspects of MAC protocols. In this paper, we investigate various types of MAC layer misbehaviors, and evaluate their effectiveness in terms of their impact on important performance aspects including throughput, and fairness to other users. We observe that the effects of misbehavior are prominent only when the network traffic is sufficiently large and the extent of misbehavior is reasonably aggressive. In addition, we find that performance gains achieved using misbehavior exhibit diminishing returns with respect to its aggressiveness, for all types of misbehaviors considered. We identify crucial common characteristics among such misbehaviors, and employ our learning to design an effective measure to react towards such misbehaviors. Employing two of the most effective misbehaviors, we study the effect of collective aggressiveness of non-selfish nodes as a possible strategy to react towards selfish misbehavior. Particularly, we demonstrate that a collective aggressive reaction approach is able to ensure fairness in the network, however at the expense of overall network throughput degradation

Diphyllobothriasis in a nine-year-old child in India: a case report

<p>Abstract</p> <p>Introduction</p> <p>The <it>Diphyllobothrium </it>genus belongs to the <it>Diphyllobothridea </it>order of tapeworms. <it>Diphyllobothrium </it>spp., which is commonly known as fish tapeworm, is generally transmitted in humans, but also in other species, such as bears, dogs, cats, foxes, and other terrestrial carnivores. Although worldwide in distribution, the original heartland of <it>Diphyllobothrium </it>spp. spreads across Scandinavia, northern Russia, and western Serbia. We report a rare case that occurred in India.</p> <p>Case presentation</p> <p>A nine-year-old south Indian girl was brought to the casualty at the Prathima Institute of Medical Sciences with complaints of vomiting and loose stools that had started three days earlier. The vomit did not have a foul smell and contained no blood or mucus, but it did contain undigested food particles. The patient described a history of recurrent abdominal pain. She was a non-vegetarian and said she had a history of eating fish.</p> <p>Conclusion</p> <p>The incidence of <it>Diphyllobothrium </it>spp. infection is infrequent in India. Since this is only the fourth reported case in India, and since the previously reported cases also involved observed pediatric patients, we emphasize the need for clinical microbiologists and pediatricians to suspect fish tapeworm infection and recommend epidemiological study of <it>Diphyllobothrium </it>spp. infection.</p