Data Mobility as a Service

© 2016 IEEE. Cloud computing and cloud services provide an alternative IT infrastructure and service models for users. The users use cloud to store their data, delegate the management of the data, and deploy their services cost-effectively. This usage model, however, raised a number of concerns relating to data control, data protection and data mobility: 1) users may lose control of their resource, 2) data protection schemes are not adequate when data is moved to a new cloud, 3) tracking and tracing changes of data location as well as accountability of data operations are not well supported. To address these issues, this paper proposes a novel cloud service for data mobility from two aspects: data mobility and data protection. A data mobility service is designed and implemented to manage data mobility and data traceability. A Location Register Database (LRD) is also developed to support the service. Furthermore, data is protected by a data security service CPRBAC (Cloud-based Privacy-Aware Role Based Access Control) and an Auditing service that are capable of verifying data operations and triggering alarms on data violations in the Cloud environment

A novel Hash-Based File Clustering scheme for efficient distributing, storing and retrieving of large scale Health Records

Cloud computing has been adopted as an efficient computing infrastructure model for provisioning resources and providing services to users. Several distributed resource models such as Hadoop and parallel databases have been deployed in healthcare-related services to manage electronic health records (EHR). However, these models are inefficient for managing a large number of small files and hence they are not widely deployed in Healthcare Information Systems. This paper proposed a novel Hash-Based File Clustering Scheme (HBFC) to distribute, store and retrieve EHR efficiently in cloud environments. The HBFC possesses two distinctive features: it utilizes hashing to distribute files into clusters in a control way and it utilizes P2P structures for data management. HBFC scheme is demonstrated to be effective in handling big health data that comprises of a large number of small files in various formats. It allows users to retrieve and access data records efficiently. The initial implementation results demonstrate that the proposed scheme outperforms original P2P system in term of data lookup latency

On wall-ice accretion or melting in shear flow

A presentation given at the Isaac Newton Institute on 30th September 2022 by Frank Smith on new joint unpublished work with UCL PhD students T D Dang and Ellen Jolley

Data mobility management model for active data cubes

© 2015 IEEE. Cloud computing dramatically reduces the expense and complexity of managing IT systems. Business customers do not need to invest in their own costly IT infrastructure, but can delegate and deploy their services effectively to cloud vendors and service providers. A number of security and protection mechanisms have been proposed to prevent the disclosure of sensitive information or tempering with the data by employing various policy, encryption, and monitoring approaches. However, few efforts have been focused on data mobility issues in terms of protection of data when it is moved within a cloud or to and from a new cloud environment. To allay users' concern of data control, data ownership, security and privacy, we propose a novel data mobility management model which ensures continuity protecting data at new cloud hosts at new data locations. The model provides a mobility service to handle data moving operation that relies on a new location database service. The new model allows the establishment of a proxy supervisor in the new environment and the ability of the active data to record its own location. The experimental outcomes demonstrate the feasibility, proactivity, and efficiency by the full mobility management model

On the flow past ellipses in a Hele-Shaw cell

n this work we investigate the effect of vertical confinement and inertia on the flow past thin ellipses in a Hele-Shaw cell (with centre line velocity Uc and height 2 h ) with different aspect ratios for symmetrical flows and at an angle of attack, using asymptotic methods and numerical simulations. A Stokes region is identified at the ellipse vertices which results in flow different to flow past bluff bodies. Comparison with asymptotic analysis indicates close agreement over the ‘flat’ portion of the ellipse, for δ=(b/a)=0.05 , where a and b are the semi-major and -minor ellipse axes, respectively. Two flow conditions are investigated for ellipses at an angle of attack of 10 ∘ for a fixed δ=0.05 . Firstly, for Λ=(Uca/ν)(h/a)2≪1 , the effect of increasing the vertical confinement of the Hele-Shaw cell results in the rear stagnation point (RSP) moving from close to the potential-flow prediction when ϵ=h/a is very small to the two-dimensional Stokes-flow prediction when ϵ is large. Secondly, for a fixed ϵ≪1 , when inertia is increased past Λ=O(ϵ) the RSP moves towards the trailing edge and is located there for Λ=O(1) . Under these conditions an attached exponentially decaying shear layer or ‘viscous tail’ is formed. A modified Bernoulli equation of the depth-averaged flow, together with the Kutta–Joukowski theorem is used to predict the drag and lift coefficients on the ellipse, which include a linear and a nonlinear contribution, corresponding to a Hele-Shaw and circulation component, respectively. Close agreement is found up to Λ=O(1)

A facile technique to prepare MgO-biochar nanocomposites for cationic and anionic nutrient removal

The removal of NH4+ and PO43− from water using adsorbents produced from rice husk and corn cob byproducts was examined. The synthesis of MgO-biochar nanocomposites was conducted by magnesium activation under nitrogen atmosphere at 400 °C and 500 °C. The characterization of different materials was performed using various modern instruments such as XPS, SEM, EDS, XRD, FT-IR, BET…The comparison between modified and unmodified biochars for removing NH4+ and PO43− from water and the impact of different parameters on adsorption capacity of obtained materials were also performed. The results showed that the activation of biochar by magnesium led to changes in surface areas, pore volume, surface charge, and chemical properties of biochars and to increases in NH4+ and PO43− adsorption capacity. The adsorption of NH4+ and PO43− onto biochar-based nanocomposites followed both chemisorption and physisorption, were spontaneous, and endothermic. The NH4+ maximum uptake calculated according to Langmuir model were 21.32 mg/g for RMgN500 and 16.31 mg/g for CMgN500 while the PO43− maximum uptake were 117.77 mg/g and 52.24 mg/g for of RMgN500 and CMgN500, respectively. The desorption and recyclability of the RMgN500 and CMgN500 were very effective by using 0.5 M NaOH solution for PO43− and diluted HCl solutions for NH4+. This approach of synthesizing MgO nanoparticles impregnated in biochar matrix provided new opportunities in developing low-cost and highly efficient adsorbent to removal and recovery of NH4+ and PO43− from water

Effects of Post-Translational Modifications of Fibrinogen on Clot Formation, Clot Structure, and Fibrinolysis: A Systematic Review

OBJECTIVE: Post-translational modifications of fibrinogen influence the occurrence and progression of thrombotic diseases. In this systematic review, we assessed the current literature on post-translational modifications of fibrinogen and their effects on fibrin formation and clot characteristics. Approach and Results: A systematic search of Medline, Embase, Cochrane Library, and Web of Science was performed to find studies reporting post-translational modifications of fibrinogen and the effects on clot formation and structure. Both in vitro studies and ex vivo studies using patient material were included. One hundred five articles were included, describing 11 different modifications of fibrinogen. For the best known and studied modifications, conclusions could be drawn about their effect on clot formation and structure. Oxidation, high levels of nitration, and glycosylation inhibit the rate of polymerization, resulting in dense clots with thinner fibers, while low levels of nitration increase the rate of polymerization. Glycation showed different results for polymerization, but f

Effects of pesticide mixtures on host-pathogen dynamics of the amphibian chytrid fungus

Anthropogenic and natural stressors often interact to affect organisms. Amphibian populations are undergoing unprecedented declines and extinctions with pesticides and emerging infectious diseases implicated as causal factors. Although these factors often cooccur, their effects on amphibians are usually examined in isolation. We hypothesized that exposure of larval and metamorphic amphibians to ecologically relevant concentrations of pesticide mixtures would increase their post-metamorphic susceptibility to the fungus Batra-chochytrium dendrobatidis (Bd), a pathogen that has contributed to amphibian population declines worldwide. We exposed five anuran species (Pacific treefrog, Pseudacris regilla; spring peeper, Pseudacris crucifer; Cascades frog, Rana cascadae; northern leopard frog, Lithobates pipiens; and western toad, Anaxyrus boreas) from three families to mixtures of four common insecticides (chlorpyrifos, carbaryl, permethrin, and endosulfan) or herbicides (glyphosate, acetochlor, atrazine, and 2,4-D) or a control treatment, either as tadpoles or as newly metamorphic individuals (metamorphs). Subsequently, we exposed animals to Bd or a control inoculate after metamorphosis and compared survival and Bd load. Bd exposure significantly increased mortality in Pacific treefrogs, spring peepers, and western toads, but not in Cascades frogs or northern leopard frogs. However, the effects of pesticide exposure on mortality were negligible, regardless of the timing of exposure. Bd load varied considerably across species; Pacific treefrogs, spring peepers, and western toads had the highest loads, whereas Cascades frogs and northern leopard frogs had the lowest loads. The influence of pesticide exposure on Bd load depended on the amphibian species, timing of pesticide exposure, and the particular pesticide treatment. Our results suggest that exposure to realistic pesticide concentrations has minimal effects on Bd-induced mortality, but can alter Bd load. This result could have broad implications for risk assessment of amphibians; the outcome of exposure to multiple stressors may be unpredictable and can differ between species and life stages

Mapping Exoplanets

The varied surfaces and atmospheres of planets make them interesting places to live, explore, and study from afar. Unfortunately, the great distance to exoplanets makes it impossible to resolve their disk with current or near-term technology. It is still possible, however, to deduce spatial inhomogeneities in exoplanets provided that different regions are visible at different times---this can be due to rotation, orbital motion, and occultations by a star, planet, or moon. Astronomers have so far constructed maps of thermal emission and albedo for short period giant planets. These maps constrain atmospheric dynamics and cloud patterns in exotic atmospheres. In the future, exo-cartography could yield surface maps of terrestrial planets, hinting at the geophysical and geochemical processes that shape them.Comment: Updated chapter for Handbook of Exoplanets, eds. Deeg & Belmonte. 17 pages, including 6 figures and 4 pages of reference