High contribution of cache access power in the total power consumption of embedded processors has made it a major concern in embedded system designs. By technology scaling, leakage power has created more stress on design constraint and power budget of embedded processors. Therefore; designers require a comprehensive design space exploration of cache architecture. In this paper we find out the optimum performance per power consumption points for cache sizes based on design space exploration using a new energy model considering dynamic and leakage energy of cache for embedded applications. Full exploration is performed based on different feature sizes to find out the effect of technology scale down on power parameters of cache. Results show that in different feature sizes 30% of static power and 43 % of total power of an embedded core is consumed in the cache hierarchy in average. It means based on this work in smaller feature sizes and for embedded application that can tolerate performance lose up to 3%, we should select smaller cache hierarchy to deliver better performance per power as the most important parameter in designing embedded systems.

Background: The next generation of learning called mobile learning (m-learning) provides education to people through mobile devices. The security of mobile systems is an important issue due to users' mobility and use of various devices and different ways of connecting to the network. Therefore, the current study aimed at providing a secure architecture as the basis for use in m-learning software to improve the security of such systems and investigate professors' satisfaction with this architecture. Methods: The current applied study was conducted in 2014. Statistical population included all professors using m-learning in Tabas, Firdaus, and Birjand cities, Southern Khorasan, Iran (26 participants). The purposive sampling method was used. The reliability of the questionnaire was measured using Cronbach's alpha (94%) and the validity based on factor validity (explained percentage of variance) was 63%. According to the use of the web-based e-learning service in Southern Khorasan Payam-e-Noor University (PNU), it was attempted to write a mobile application to provide the use of this service on mobile devices. The difference between the current study provided app and other mobile apps is based on using the proposed secure architecture. To measure the satisfaction of users with the study app, a researcher-made questionnaire was distributed among the professors using the app. Data analysis was performed with SPSS 16 by t test and the one-way analysis of variance (ANOVA). Results: Findings showed that the professors using m-learning application of Southern Khorasan PNU had a positive attitude towards it with the average satisfaction of 80%. The most important factor for this satisfaction was the safety of the presented architecture, while avoiding complex and time-consuming control mechanisms. Conclusions: In the current study a secure architecture was provided for mobile system that was simple, fast, and applicable on all mobile network operators. Given the positive perspectives of professors, this architecture can be a good solution to secure mlearning environments.