MUTE: MUlti-Tier Edge Networks

Several Internet-of-Things (IoT) based use-cases require an increased amount of computation resources with extremely low latency. Cloud-based services may fail to provide such requirement given the high latency required to access their facilities. Therefore, an increasing number of resources are being deployed at the network "edge" as Edge Clouds. However, as the modeling of edge network is still in its early stages, the existing solutions for service placement and resource utilization are found to be quite inefficient. In this paper, we model a multi-tier edge network and propose a service placement algorithm, Mute. In our evaluation, performed on real network topologies, we show that Mute achieves 66% reduction in network cost and 50% reduction in service placement when compared to state-of-the-art solutions.Peer reviewe

Progress to extinction : increased specialisation causes the demise of animal clades

Animal clades tend to follow a predictable path of waxing and waning during their existence, regardless of their total species richness or geographic coverage. Clades begin small and undifferentiated, then expand to a peak in diversity and range, only to shift into a rarely broken decline towards extinction. While this trajectory is now well documented and broadly recognised, the reasons underlying it remain obscure. In particular, it is unknown why clade extinction is universal and occurs with such surprising regularity. Current explanations for paleontological extinctions call on the growing costs of biological interactions, geological accidents, evolutionary traps, and mass extinctions. While these are effective causes of extinction, they mainly apply to species, not clades. Although mass extinctions is the undeniable cause for the demise of a sizeable number of major taxa, we show here that clades escaping them go extinct because of the widespread tendency of evolution to produce increasingly specialised, sympatric, and geographically restricted species over time.Peer reviewe

Age-Related Modifications of Muscle Synergies and Spinal Cord Activity During Locomotion

Monaco V, Ghionzoli A, Micera S. Age-related modifications of muscle synergies and spinal cord activity during locomotion. J Neurophysiol 104: 2092-2102, 2010. First published August 4, 2010; doi:10.1152/jn.00525.2009. Recent findings have shown that neural circuits located in the spinal cord drive muscular activations during locomotion while intermediating between descending signals and peripheral sensory information. This relationship could be modified by the natural aging process. To address this issue, the activity of 12 ipsilateral leg muscles was analyzed in young and elderly people (7 subjects per group) while walking at six different cadences (40-140 steps/min). These signals were used to extract synergies underlying muscle activation and to map the motoneuronal activity of the pools belonging to the lumbosacral enlargement (L-2-S-2). The comparison between the two groups showed that neither temporal patterning of motor primitives nor muscles loading synergies seemed to be significantly affected by aging. Conversely, as the cadence increased, spinal maps differ significantly between the groups, showing higher and scattered activity during the whole gait cycle in elders and well-defined bursts in young subjects. The results suggested that motor primitives lead the synchronization of muscle activation mainly depending on the biomechanical demand of the locomotion; hence they are not significantly affected by aging. Nevertheless, at the spinal cord level, biomechanical requirements, peripheral afference, and descending inputs are differently integrated between the two groups, probably reflecting age-related changes of both nervous system and motor control strategies during locomotion

Visual Feedback of Bilateral Bite Force to Assess Motor Control of the Mandible in Isometric Condition

The assessment of the individual ability of modulating and coordinating the right and left bite force is poorly investigated. The present study describes a methodology for the assessment of the bilateral control of the biting force and evaluates the test-retest reliability in a sample of 13 healthy subjects. By modulating the intensity and the left/right balance of the biting force, the subject was able to drive a cursor on the screen in order to "reach and hold" targets, randomly generated within the physiological "range of force" of the subject. The average motor performance was evaluated by the Mean cursor-target Distance= 13 \ub15%, the Offset Error= 9 \ub15%and the Standard Deviation of the force vector = 17.7 \ub1 6.1% (expressed as % of the target). Mean Distance and Standard Deviation indices had acceptable reliability. This technique improves the characterization of the mandibular motor function and it may have a relevant role for the assessment and rehabilitation of the neuromusculoskeletal disorders affecting the orofacial system