Performance evaluation of the RPL Protocol in fixed and mobile sinks low-power and lossy networks.

Low-Power and Lossy-Network (LLN) are usually composed of static nodes, but the increase demand for mobility in mobile robotic and dynamic environment raises the question how a routing protocol for low-power and lossy-networks such as (RPL) would perform if a mobile sink is deployed. In this paper we investigate and evaluate the behaviour of the RPL protocol in fixed and mobile sink environments with respect to different network metrics such as latency, packet delivery ratio (PDR) and energy consumption. Extensive simulation using instant Contiki simulator show significant performance differences between fixed and mobile sink environments. Fixed sink LLNs performed better in terms of average power consumption, latency and packet delivery ratio. The results demonstrated also that RPL protocol is sensitive to mobility and it increases the number of isolated nodes.

Moodle on the Move.

Recent shifts in technology have seen some writers question the value of tablet computers as phones becomes bigger, more powerful and their battery life improves: (http://www.wired.com/2015/01/nobody-knows-ipad-good-anymore/ In trying to encourage greater student engagement with their studies, lecturers can be caught unsure of how to proceed. Moodle has improved since its introduction and now it adjusts the content to match the screen size. Does that matter? Results from a recent module survey suggests that 75% of students access Moodle from their phone which would suggest that when we design our Moodle pages we may need to think about the placement of information. What works on a 21" HD monitor in our office may not give the same result on a laptop, tablet or phone.