IEEE 802.11ah brings in Restricted Access Window (RAW) to decrease contention, which is the grouping-based MAC protocol. The way to group a large number of devices and application of RAW size would have influence on the energy efficiency in the process of medium access and communications. In this paper, we study an efficient window control algorithm to improve the uplink energy efficiency with ...

This paper presents a protocol which improves on the power saving mechanism in the IEEE 802.11 Distributed Coordination Function (DCF). In the power saving mechanism (PSM) for DCF, all nodes are synchronized by beacons. In each beacon interval, there is a fixed time interval called the ATIM window where every node has to be awake. During the ATIM window, a source node informs a destination node...

We propose here an extended linear feedback model, taking the binary exponential backoff mechanism adopted in IEEE 802.15.4 CSMA/CA and analyze the energy consumption issues of the one hop sensor nodes. Numerical results show that the energy consumption in Wireless Sensor Networks (WSNs) can be reduced by applying CSMA protocol with fixed contention window size. Besides, an optimal contention w...

The numerical investigation of computing the rate of radiated solar-energy requires equations as a function of solar-time according to the radiation angle of the sun (β) in the latitude 37°N and the shape. This paper implements the Lagrange interpolation to obtain the equations of normal diagram of elements based on data obtained from surveying. Also the method of Hann-window equation ...

Simulations using Monte-Carlo packages are increasingly used in Nuclear Imaging, both for PET and SPECT applications. Either for modeling imaging systems or developing algorithms for analysis and improvement of image quantification. The aim of this work is the study of several scatter phenomena and the evaluation and improvement of two scatter correction compensation methods in pixelized scinti...

The azimuthal asymmetry of minijet system produced at the early stage of nucleon-nucleon and nuclear collisions in a central rapidity window is studied. We show that in pp collisions the minijet transverse energy production in a central rapidity window is essentially unbalanced in azimuth due to asymmetric contributions in which only one minijet hits the acceptance window. We further study the ...