On Information and Energy Cooperation in Energy Harvesting Cognitive Radio

This paper considers the cooperation between primary and secondary users at information and energy levels when both users are energy harvesting nodes. In particular, a secondary transmitter helps relaying the primary message, and in turn, gains the spectrum access as a reward. Also, the primary transmitter supplies energy to the secondary transmitter if the latter is energy-constrained, which facilitates an uninterrupted cooperation. We address this two-level cooperation over a finite horizon with the finite battery constraint at the secondary transmitter. While promising the rate-guaranteed service to both primary and secondary users, we aim to maximize the primary rate. We develop an iterative algorithm that obtains the optimal offline power policies for primary and secondary users. To acquire insights about the structure of the optimal solution, we examine specific scenarios. Furthermore, we investigate the effects of the secondary rate constraint and finite battery on the primary rate and the probability of cooperation. We show that the joint information and energy cooperation increases the chances of cooperation and achieves significant rate gains over only information cooperation.Comment: 6 pages, 4 figures, to be presented in IEEE PIMRC 201

Prevalence of mandibular third molar impaction and agenesis: A radiographic South Indian study

Aims and objective: To evaluate the prevalence of (i) impaction of mandibular third molar, (ii) agenesis of mandibular third molar and (iii) angulation of impaction radiographically. Materials and methods: The sample size consists of 1,005 patients above 18 years. The orthopantomograph of the patients are interpreted for eruption/pattern of impaction/agenesis of mandibular third molar. Conclusion: Bilateral impaction of mandibular third molar is common than unilateral impaction. Agenesis of mandibular third molar is seen in 122 to 12.5% of patients. Mesioangular is the commonest pattern of impaction No sex predisposition is in prevalence of impaction. Agenesis is seen more commonly in females than males