CFP: IJDSN - Special Issue (SCIE Indexed), Deadline: Friday, 10 July 2015

International Journal of Distributed Sensor Networks (IJDSN) invites paper for the special issue on -

"Applications of Cognitive Radio Networks: Recent Advances and Future Directions"

Call for Papers

The demand of spectrum increased tremendously due to the recent advancements in wireless communication technology. This dramatic requirement of spectrum has challenged the current spectrum licensing system and inspired authorities to legalize opportunistic spectrum access. Recently, many authorities, researchers, and hardware manufacturers are working to solve this virtual scarcity issue. Cognitive radio (CR) networks are suitable in this mitigation, by utilizing licensed spectrum opportunistically. CR is rapidly proliferating into many wireless communication fields. Spectrum sensing, spectrum sharing, coexistence, spread spectrum, and MIMO techniques have become areas of concern over the past decade. More recently, many researchers are working in various application areas of cognitive radio networks (CRNs) and cognitive radio wireless sensor networks (CR-WSNs).

Research Assistant (Nano-technology & Chemical Reaction Engineering)

Applications are invited for a Research Assistant (R/A) position at the Chemical and Petroleum Engineering Department of the UAE University (www.uaeu.ac.ae).

NS2 (Network Simulator) resources

A link that answers you all.

http://www.matlab.nitech.ac.jp/~khpoo/research/ns2.html

Some other links

http://hpds.ee.ncku.edu.tw/~smallko/ns2/ns2.htm

Advice to the graduate students

http://www.cse.psu.edu/~yuanxie/advice.htm

Why queue if λ/μ < 1 ?

In Poisson distribution, why there is a queue even though λ/μ < 1. Where λ is an arrival rate and μ is a service time?

Because λ and μ are the average (or expected) value of distribution. It doesn’t mean that in every t second a customer arrives into the system. Inter-arrival (the time between consecutive events) time are exponentially distributed and arrival rate is Poisson. It means the time between two consecutive arrivals are different.
In other words, even though λ/μ < 1, two or more customers may come to the system at the same time and system can serve only one customers at one time. So, we need queue. For example: average arrival rate (λ) = 10 customer per hour, average service rate (μ) is 15 customer per hour. It means λ/μ <1. However, it follows Poisson distribution, so, two customer (or in the worst case, all the 10 customers) may come at the same time. That’s why we need queue.