Throughput Analysis of Primary and Secondary Networks in a Shared IEEE 802.11 System

In this paper, we analyze the coexistence of a primary and a secondary (cognitive) network when both networks use the IEEE 802.11 based distributed coordination function for medium access control. Specifically, we consider the problem of channel capture by a secondary network that uses spectrum sensing to determine the availability of the channel, and its impact on the primary throughput. We integrate the notion of transmission slots in Bianchi's Markov model with the physical time slots, to derive the transmission probability of the secondary network as a function of its scan duration. This is used to obtain analytical expressions for the throughput achievable by the primary and secondary networks. Our analysis considers both saturated and unsaturated networks. By performing a numerical search, the secondary network parameters are selected to maximize its throughput for a given level of protection of the primary network throughput. The theoretical expressions are validated using extensive simulations carried out in the Network Simulator 2. Our results provide critical insights into the performance and robustness of different schemes for medium access by the secondary network. In particular, we find that the channel captures by the secondary network does not significantly impact the primary throughput, and that simply increasing the secondary contention window size is only marginally inferior to silent-period based methods in terms of its throughput performance.Comment: To appear in IEEE Transactions on Wireless Communication

On the polar decomposition of right linear operators in quaternionic Hilbert spaces

In this article we prove the existence of the polar decomposition for densely defined closed right linear operators in quaternionic Hilbert spaces: If $T$ is a densely defined closed right linear operator in a quaternionic Hilbert space $H$, then there exists a partial isometry $U_{0}$ such that $T = U_{0}|T|$. In fact $U_{0}$ is unique if $N(U_{0}) = N(T)$. In particular, if $H$ is separable and $U$ is a partial isometry with $T = U|T|$, then we prove that $U = U_{0}$ if and only if either $N(T) = \{0\}$ or $R(T)^{\bot} = \{0\}$.Comment: 17 page

Formulation and Evaluation of Serratiopeptidase tablets

Serratiopeptidase is derived from bacteria belonging to genus Serratia. Serratiopeptidase tablets used in the treatment of viral diseases and hepatitis. In this study Serratiopeptidase enteric coated tablets were prepared by using HPMC phthalate, HPMC 15cps (Polymer). Several formulations were made with varying the concentrations of drug polymer and enteric coating tablets were done by wet granulation method. They were tested for normal quality control tests like disintegration, weight variation, hardness and friability. The drug release study is carried out for 2hrs in 0.1N HCl and followed with 1hr in 6.8 phosphate buffer. The present work of Serratiopeptidase was formulated as delayed release tablet which significantly increase the small intestinal absorption and the drug was targeted to small intestinal regions. This was achieved by enteric coating of tablets by simple standard pan coating method. Serratiopeptidase were formulated using HPMC phthalate as enteric coating polymer in different concentrations to optimize delayed drug release profile and to target the drug release in the small intestine regions. The present work was made to develop enteric coated tablets containing Serratiopeptidase tablets were made by direct compression method. While concluding the best formulation among the six F1 formulation shows 99.94% drug release than the all other formulations

Total edge irregularity strength of join of path and complement of a complete graph

An edge irregular total k-labeling of a graph G is a labeling of the vertices and edges of G with labels from the set {1, 2, ..., k} in such a way that any two different edges have distinct weights. The weight of an edge uv is the sum of the label of uv and the labels of vertices u and v. The minimum k for which the graph G has an edge irregular total k-labeling is called the total edge irregularity strength of G. In this paper, we determine the exact value of the total edge irregularity strength of Pn + Km.Publisher's Versio

Pharmacological and Clinical Importance of Integrin Antagonists in Treatment of Cancer

Integrins are heterodimeric molecules that are composed of 18 α -subunits and 8 β -subunits. They exist in 24 distinctive shapes based on combination of these sub-units and are mainly responsible for the adhesion of extracellular matrix (ECM) and immunoglobulin family molecules. Integrins mediate adhesion of epithelial cells to the basement membrane and also help in the migration, proliferation and survival of tumor cells. Studies also reveal that certain integrins act as markers for tumor cells and they also assist in both tumor progression and apoptosis. Studies reveal that unligated integrins in association with caspase 8 result in inhibition of ECM adhesion might result and integrin mediated death (IMD) on the other hand integrins in association with oncogenes or receptor tyrosine kinases can result in enhanced tumorigenesis. Among several types of integrins, αvβ 3 and α 5 β 1 have gained importance in anti-angiogenesis studie

Growth performance of the tea clone TRF-1 under Nilgiri conditions

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Small Carnivores of Biligiri Rangaswamy Temple Tiger Reserve, Karnataka, India

During the present study in Biligiri Rangaswamy Temple Tiger Reserve (BRT), nine species of small carnivores viz., Jungle Cat Felis chaus, Rusty-spotted Cat Prionalilurus rubiginosus, Leopard Cat Prionailurus bengalensis, Small Indian Civet Viverricula indica, Asian Palm Civet Paradoxurus hermaphroditus, Striped-necked Mongoose Herpestes vitticollis, Ruddy Mongoose Herpestes smithii, Common Mongoose Herpestes edwardsii and Smooth-coated Otter Lutrogale perspicillata, were recorded using camera-trapping technique, transect walks, and night surveys. Vegetation type strongly influences the presence and abundance of each species. The most sightings of small carnivores occurred in dry deciduous forests. Among all the species, the Asian Palm Civet was the most abundant and was followed by the small Indian Civet. Compared to many other forests or regions in India, the sight records of the Rusty-spotted Cat were relatively higher in BRT. Although we were unable to use statistical methods to search for higher levels of interdependencies between forest types and small carnivore abundance, our study sheds light on patterns of small carnivore distribution in this unique habitat which bridges the Western Ghats and the Eastern Ghats

Priority based energy efficient hybrid cluster routing protocol for underwater wireless sensor network

A little change in the environment that goes unnoticed in an underwater communication network might lead to calamity. A little alteration in the environment must also be adequately analyzed in order to deal with a potential crisis. A priority-based routing protocol is required to ensure that the vital data perceived by the sensor about the environment changes. The priority-based routing system guarantees that vital data packets are delivered at a quicker pace to the destination or base station for further processing. In this work, we present a priority-based routing protocol based on the energy efficient hybrid cluster routing protocol (EEHRCP) algorithm. The suggested approach keeps two distinct queues for lower and higher priority data packets. In order to ensure that these packets get at their destination without any information loss and at a quicker rate, all of the crucial sensed data is passed through a higher priority queue. Test findings show that the suggested technique increases throughput, delivery percentage, and reduces latency for the crucial data packets