Selective and private access to outsourced data centers

The advancements in the Information Technology and the rapid diffusion of novel computing paradigms have accelerated the trend of moving data to the cloud. Public and private organizations are more often outsourcing their data centers to the cloud for economic and/or performance reasons, thus making data confidentiality an essential requirement. A basic technique for protecting data confidentiality relies on encryption: data are encrypted by the owner before their outsourcing. Encryption however complicates both the query evaluation and enforcement of access restrictions to outsourced data. In this chapter, we provide an overview of the issues and techniques related to the support of selective and private access to outsourced data in a scenario where the cloud provider is trusted for managing the data but not for reading their content. We therefore illustrate methods for enforcing access control and for efficiently and privately executing queries (at the server side) over encrypted data. We also show how the combined adoption of approaches supporting access control and for efficient query evaluation may cause novel privacy issues that need to be carefully handled

Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

Prediction of second neurological attack in patients with clinically isolated syndrome using support vector machines

The aim of this study is to predict the conversion from clinically isolated syndrome to clinically definite multiple sclerosis using support vector machines. The two groups of converters and non-converters are classified using features that were calculated from baseline data of 73 patients. The data consists of standard magnetic resonance images, binary lesion masks, and clinical and demographic information. 15 features were calculated and all combinations of them were iteratively tested for their predictive capacity using polynomial kernels and radial basis functions with leave-one-out cross-validation. The accuracy of this prediction is up to 86.4% with a sensitivity and specificity in the same range indicating that this is a feasible approach for the prediction of a second clinical attack in patients with clinically isolated syndromes, and that the chosen features are appropriate. The two features gender and location of onset lesions have been used in all feature combinations leading to a high accuracy suggesting that they are highly predictive. However, it is necessary to add supporting features to maximise the accuracy. © 2013 IEEE

Construction Monitoring And Back Analysis of Rock Mass Modulus of a Rock Cavern In Hong Kong

With the introduction of a new four-year degree program at The University of Hong Kong, a Centennial Campus is being developed at the western side of the existing Main Campus. The scope of this infrastructure project comprises the design, construction and commissioning of two new salt water and two new fresh water service reservoirs. Cavern was excavated in sandstone and tuff to accommodate the new salt water reservoir in a twin-cell tunnel system. The cavern was constructed inside a sloping ground due to the need to find adequate rock cover. Starting at the portal, an about 30 m long, 7.2 m span access tunnel was constructed and then separated into two reservoir tunnels. Two 10 m long transition zones were constructed and then the tunnels were enlarged from 7.2 m span to 17 m span to create the cavern for the new salt water reservoir. With the requirements of minimal damage and disturbance to the rock mass during the excavation, it provided an ample opportunity to study the convergence of the cavern as the excavation approached an undisturbed zone. This paper presents an evaluation of the magnitude of stresses acting on the crown of the large span tunnel at different stages of ground movement. Back analysis was carried out based on the observed stresses and deformation resulted from approximately 6 m high top heading tunnel excavation. Two-dimensional finite element analysis program was utilized for this back analysis. Different empirical equations such as Bieniawski, Serafim and Pereira, Barton and Hoek et al. have been used in the numerical analysis to simulate the rock mass behaviors. It revealed that the Serafim and Pereira estimation was generally applicable for this particular HKU cavern project with volcanic tuff bedrock of as-mapped Q-value higher than 2.3 or RMR value higher than 50. The observed monitoring records also demonstrated that approximately 2 mm of vertical deformation was mobilized to provide an efficient temporary support to the tunnel crown. Little stress relief and deformation was observed after the temporary rock support has been substantially mobilized. This paper presents a case-study of the rock behavior due to the underground opening. It also demonstrated the performance of immediate support to the tunnel crown in controlling the ground settlement and stress relaxation

Association of Streptococcus mutans Infection and Oral Developmental Nodules in Pre-dentate Infants

Since dental caries may present soon after tooth eruption, we hypothesized that colonization of Streptococcus mutans can occur in the predentate stages. In this study, we examined S. mutans colonization and its association with oral developmental nodules (Bohn's nodules) in 60 pre-term and 128 full-term, three-month-old infants. Overall, S. mutans was cultured from 30% (56/188) of the infants, and oral developmental nodules were noted in 55% (103/188). Compared with the pre-term, full-term infants showed a higher prevalence of S. mutans (34% vs. 20%, p < 0.02) as well as developmental nodules (61% vs. 42%, p < 0.05). In both groups, S. mutans was positively associated with numbers of developmental nodules in a dose-response relationship (p < 0,001), and with maternal salivary levels of the bacteria (p = 0.03). The permanence of S. mutans infection was confirmed by repeat saliva sampling at 6 months of age. Our results thus showed that many infants have already acquired S. mutans at 3 months of age, prior to tooth eruption

Improving health behaviours during pregnancy: A new direction for the pregnancy handheld record

Obstetric documentation processes may influence the clinical, behavioural, and psychological outcomes of pregnancy, although recent alterations to integrate obstetric documentation with pregnancy handheld records have been unsuccessful. Woman-held records as a companion to usual obstetric documentation have the potential to improve pregnancy-related health behaviours with a demonstrated association with maternal and infant health outcomes, and recommendations for their format and content are provided