mobile phones, mobile phone base stations, cordless phones and power lines are among the main sources of our daily exposures to radiofrequency electromagnetic fields (rf-emf). today, a large proportion of children aged eight and under has used smart phones and tablets for media activities such as playing online games, watching videos or using different applications. over the past several years,...

The present study aims to investigate language learners’ cognitive processes in on-line ESP courses. Three modes of inquiry are used: think-aloud protocol analysis, screen capture analysis, and correlation analysis. The theoretical foundations for the evaluation of the cognitive aspect of Ferdowsi Univeristy of Mashhad E-learning System are drawn from cognitive load theory, cognitive apprentice...

Spectrum sensing is an essential functionality of cognitive radio networks. In the existing Cognitive Radio spectrum detection techniques secondary nodes base their channel access decisions solely on the outcome of the spectrum sensor without taking into consideration the possibility that those outcomes are incorrect. To alleviate these negative effects a combined design is proposed for the sec...

Oneof themost efficientmethods to reduce the dropping andblockingprobabilities of the secondary users (SUs) in cognitive radio networks is channel sub-banding strategy. This means that when all the channels are occupied by the primary and secondary users, then the SUs’ channels can be divided into two sub-bands, and two SUs can use a subband, simultaneously. In this paper, we propose an opportu...

This paper proposes an energy-efficient routing scheme that is based on a resource intensive traffic-aware approach, enabling for the maximization of the energy conservation in cognitive radio networks. The proposed approach interrelates the moments of the backward difference traffic, together with the sleep-time duration, towards tuning the activity periods of the network nodes. The effective ...

In wireless networks, context awareness and intelligence are capabilities that enable each host to observe, learn, and respond to its complex and dynamic operating environment in an efficient manner. These capabilities contrast with traditional approaches where each host adheres to a predefined set of rules, and responds accordingly. In recent years, context awareness and intelligence have gain...

Recently, both optimal and suboptimal spectrum sensing approaches have attracted extensive attention in wireless communications field. Thanks to opportunistic spectrum access schemes, different cognitive users can cooperatively search for and exploit instantaneous spectrum availability. In this paper, we address the analysis of spectrum sensing in opportunistic spectrum access models and then d...

background: cognitive impairment profoundly influences on older adults’ activities and quality of life. therefore, optimizing and remediating age-associated cognitive decline have great importance. objectives: to evaluate the effect of 8 weeks (3 day /week) computer based brain training on cognitive performance in old women with mild cognitive impairment (mci). materials and methods: this rando...