Certifying Services in Cloud: The Case for a Hybrid, Incremental and Multi-layer Approach

The use of clouds raises significant security concerns for the services they provide. Addressing these concerns requires novel models of cloud service certification based on multiple forms of evidence including testing and monitoring data, and trusted computing proofs. CUMULUS is a novel infrastructure for realising such certification models

Big Data Assurance Evaluation: An SLA-Based Approach.

The Big Data community has started noticing that there is the need to complete Big Data platforms with assurance techniques proving the correct behavior of Big Data analytics and management. In this paper, we propose a Big Data assurance solution based on Service-Level Agreements (SLAs), focusing on a platform providing Model-based Big Data Analytics-as-a-Service (MBDAaaS)

Solar particle effects on minor components of the Polar atmosphere

Abstract. Solar activity can influence the Earth's environment, and in particular the ozone layer, by direct modulation of the e.m. radiation or through variability of the incoming cosmic ray flux (solar and galactic particles). In particular, solar energetic particles (SEPs) provide additional external energy to the terrestrial environment; they are able to interact with the minor constituents of the atmospheric layer and produce ionizations, dissociations, dissociative ionizations and excitations. This paper highlights the SEP effects on the chemistry of the upper atmosphere by analysing some SEP events recorded during 2005 in the descending phase of the current solar cycle. It is shown that these events can lead to short- (hours) and medium- (days) term ozone variations through catalytic cycles (e.g. HOx and NOx increases). We focus attention on the relationship between ozone and OH data (retrieved from MLS EOS AURA) for four SEP events: 17 and 20 January, 15 May and 8 September. We confirm that SEP effects are different on the night and day hemispheres at high latitudes.</p

Evolution of angular-momentum-losing exoplanetary systems : Revisiting Darwin stability

We assess the importance of tidal evolution and its interplay with magnetic braking in the population of hot-Jupiter planetary systems. By minimizing the total mechanical energy of a given system under the constraint of stellar angular momentum loss, we rigorously find the conditions for the existence of dynamical equilibrium states. We estimate their duration, in particular when the wind torque spinning down the star is almost compensated by the tidal torque spinning it up. We introduce dimensionless variables to characterize the tidal evolution of observed hot Jupiter systems and discuss their spin and orbital states using generalized Darwin diagrams based on our new approach. We show that their orbital properties are related to the effective temperature of their host stars. The long-term evolution of planets orbiting F- and G-type stars is significantly different owing to the combined effect of magnetic braking and tidal dissipation. The existence of a quasi-stationary state, in the case of short-period planets, can significantly delay their tidal evolution that would otherwise bring the planet to fall into its host star. Most of the planets known to orbit F-type stars are presently found to be near this stationary state, probably in a configuration not too far from that they had when their host star settled on the zero-age main sequence. Considering the importance of angular momentum loss in the early stages of stellar evolution, our results indicate that it has to be taken into account also to properly test the migration scenarios of planetary system formation.Comment: 22 pages, 11 figures, accepted for publication in A&

A smart tablet application to quantitatively assess the dominant hand dexterity

Background and objective: The Nine-Hole Peg Test (NHPT) is the most used test to assess hand dexterity in clinical practice and is considered the gold standard but only evaluates the time needed to complete the task. The aim of this work is to describe a graphic test on a smart tablet to assess in a quantitative as well qualitative way the dominant hand dexterity and to validate it in a cohort of neurological subjects and healthy controls. Methods: The task consists in asking the subject to connect with a graphic line the start and the end point of a pre-defined path, with two different widths, in the most precise and fastest way possible. The path is constituted by a ‘meander’ and a ‘spiral’ part. The subjects perform the task on a smart tablet with a capacitive pen four times. The three parameters of interest considered at each trial are the execution time, length path, and number of interactions with the border. The app automatically computes these three parameters and stores the completed test files. The results of the digital graphic test are compared to the NHPT results. Healthy and pathological subjects are compared to each other, and performances obtained in different repetitions are compared to assess the learning effect in each population. Results: 53 subjects with a definitive diagnosis of neurodegenerative/genetic neurological disorders (34 men, mean age 59.1 ± 16.1) and 78 healthy controls (33 men, mean age 42.5 ± 16.3) were recruited. Among the pathological subjects, 31 also performed the NHPT. The graphic test clearly distinguish between the two populations for all parameters of interest. Moreover, compared to the gold standard NHPT, time has a moderate positive correlation (r = 0.57, p ≤ 0.001), whereas interactions and length have a strong positive correlation (r = 0.81, p ≤ 0.001) and (r = 0.69, p ≤ 0.001), respectively. Conclusions: The proposed digital test can measure in an accurate, quantitative and qualitative way dominant hand disability and can result more informative with respect to the gold standard NHPT. In homogeneous cohort of subjects (for example affected by multiple sclerosis or Parkinson disease), the digital test can be used as an outcome measure in clinical trials as well as a tool for monitoring disease progression at the dominant hand level